MFV f83ac37f1e66: libbsdxml (expat) 2.4.3.

85 files changed, 4183 insertions, 1503 deletions

diff --git a/contrib/expat/COPYING b/contrib/expat/COPYING
index 8d288f0f28fd..3c0142e71c8d 100644
--- a/contrib/expat/COPYING
+++ b/contrib/expat/COPYING
@@ -1,5 +1,5 @@
 Copyright (c) 1998-2000 Thai Open Source Software Center Ltd and Clark Cooper
-Copyright (c) 2001-2017 Expat maintainers
+Copyright (c) 2001-2019 Expat maintainers
 
 Permission is hereby granted, free of charge, to any person obtaining
 a copy of this software and associated documentation files (the
diff --git a/contrib/expat/Changes b/contrib/expat/Changes
index 340947118a3f..7540d38ca822 100644
--- a/contrib/expat/Changes
+++ b/contrib/expat/Changes
@@ -2,7 +2,283 @@ NOTE: We are looking for help with a few things:
       https://github.com/libexpat/libexpat/labels/help%20wanted
       If you can help, please get in touch.  Thanks!
 
-Release 2.2.9 Wed Septemper 25 2019
+Release 2.4.3 Sun January 16 2022
+        Security fixes:
+       #531 #534  CVE-2021-45960 -- Fix issues with left shifts by >=29 places
+                    resulting in
+                      a) realloc acting as free
+                      b) realloc allocating too few bytes
+                      c) undefined behavior
+                    depending on architecture and precise value
+                    for XML documents with >=2^27+1 prefixed attributes
+                    on a single XML tag a la
+                    "<r xmlns:a='[..]' a:a123='[..]' [..] />"
+                    where XML_ParserCreateNS is used to create the parser
+                    (which needs argument "-n" when running xmlwf).
+                    Impact is denial of service, or more.
+       #532 #538  CVE-2021-46143 (ZDI-CAN-16157) -- Fix integer overflow
+                    on variable m_groupSize in function doProlog leading
+                    to realloc acting as free.
+                    Impact is denial of service or more.
+            #539  CVE-2022-22822 to CVE-2022-22827 -- Prevent integer overflows
+                    near memory allocation at multiple places.  Mitre assigned
+                    a dedicated CVE for each involved internal C function:
+                    - CVE-2022-22822 for function addBinding
+                    - CVE-2022-22823 for function build_model
+                    - CVE-2022-22824 for function defineAttribute
+                    - CVE-2022-22825 for function lookup
+                    - CVE-2022-22826 for function nextScaffoldPart
+                    - CVE-2022-22827 for function storeAtts
+                    Impact is denial of service or more.
+
+        Other changes:
+            #535  CMake: Make call to file(GENERATE [..]) work for CMake <3.19
+            #541  Autotools|CMake: MinGW: Make run.sh(.in) work for Cygwin
+                    and MSYS2 by not going through Wine on these platforms
+       #527 #528  Address compiler warnings
+       #533 #543  Version info bumped from 9:2:8 to 9:3:8;
+                    see https://verbump.de/ for what these numbers do
+
+        Infrastructure:
+            #536  CI: Check for realistic minimum CMake version
+       #529 #539  CI: Cover compilation with -m32
+            #529  CI: Store coverage reports as artifacts for download
+            #528  CI: Upgrade Clang from 11 to 13
+
+        Special thanks to:
+            An anonymous whitehat
+            Christopher Degawa
+            J. Peter Mugaas
+            Tyson Smith
+                 and
+            GCC Farm Project
+            Trend Micro Zero Day Initiative
+
+Release 2.4.2 Sun December 19 2021
+        Other changes:
+       #509 #510  Link againgst libm for function "isnan"
+       #513 #514  Include expat_config.h as early as possible
+            #498  Autotools: Include files with release archives:
+                    - buildconf.sh
+                    - fuzz/*.c
+       #507 #519  Autotools: Sync CMake templates
+       #495 #524  CMake: MinGW: Fix pkg-config section "Libs" for
+                    - non-release build types (e.g. -DCMAKE_BUILD_TYPE=Debug)
+                    - multi-config CMake generators (e.g. Ninja Multi-Config)
+       #502 #503  docs: Document that function XML_GetBuffer may return NULL
+                    when asking for a buffer of 0 (zero) bytes size
+       #522 #523  docs: Fix return value docs for both
+                    XML_SetBillionLaughsAttackProtection* functions
+       #525 #526  Version info bumped from 9:1:8 to 9:2:8;
+                    see https://verbump.de/ for what these numbers do
+
+        Special thanks to:
+            Dong-hee Na
+            Joergen Ibsen
+            Kai Pastor
+
+Release 2.4.1 Sun May 23 2021
+        Bug fixes:
+       #488 #490  Autotools: Fix installed header expat_config.h for multilib
+                    systems; regression introduced in 2.4.0 by pull request #486
+
+        Other changes:
+       #491 #492  Version info bumped from 9:0:8 to 9:1:8;
+                    see https://verbump.de/ for what these numbers do
+
+        Special thanks to:
+            Gentoo's QA check "multilib_check_headers"
+
+Release 2.4.0 Sun May 23 2021
+        Security fixes:
+   #34 #466 #484  CVE-2013-0340/CWE-776 -- Protect against billion laughs attacks
+                    (denial-of-service; flavors targeting CPU time or RAM or both,
+                    leveraging general entities or parameter entities or both)
+                    by tracking and limiting the input amplification factor
+                    (<amplification> := (<direct> + <indirect>) / <direct>).
+                    By conservative default, amplification up to a factor of 100.0
+                    is tolerated and rejection only starts after 8 MiB of output bytes
+                    (=<direct> + <indirect>) have been processed.
+                    The fix adds the following to the API:
+                    - A new error code XML_ERROR_AMPLIFICATION_LIMIT_BREACH to
+                      signals this specific condition.
+                    - Two new API functions ..
+                      - XML_SetBillionLaughsAttackProtectionMaximumAmplification and
+                      - XML_SetBillionLaughsAttackProtectionActivationThreshold
+                      .. to further tighten billion laughs protection parameters
+                      when desired.  Please see file "doc/reference.html" for details.
+                      If you ever need to increase the defaults for non-attack XML
+                      payload, please file a bug report with libexpat.
+                    - Two new XML_FEATURE_* constants ..
+                      - that can be queried using the XML_GetFeatureList function, and
+                      - that are shown in "xmlwf -v" output.
+                    - Two new environment variable switches ..
+                      - EXPAT_ACCOUNTING_DEBUG=(0|1|2|3) and
+                      - EXPAT_ENTITY_DEBUG=(0|1)
+                      .. for runtime debugging of accounting and entity processing.
+                      Specific behavior of these values may change in the future.
+                    - Two new command line arguments "-a FACTOR" and "-b BYTES"
+                      for xmlwf to further tighten billion laughs protection
+                      parameters when desired.
+                      If you ever need to increase the defaults for non-attack XML
+                      payload, please file a bug report with libexpat.
+
+        Bug fixes:
+       #332 #470  For (non-default) compilation with -DEXPAT_MIN_SIZE=ON (CMake)
+                    or CPPFLAGS=-DXML_MIN_SIZE (GNU Autotools): Fix segfault
+                    for UTF-16 payloads containing CDATA sections.
+       #485 #486  Autotools: Fix generated CMake files for non-64bit and
+                    non-Linux platforms (e.g. macOS and MinGW in particular)
+                    that were introduced with release 2.3.0
+
+        Other changes:
+       #468 #469  xmlwf: Improve help output and the xmlwf man page
+            #463  xmlwf: Improve maintainability through some refactoring
+            #477  xmlwf: Fix man page DocBook validity
+       #458 #459  CMake: Support absolute paths for both CMAKE_INSTALL_LIBDIR
+                    and CMAKE_INSTALL_INCLUDEDIR
+       #471 #481  CMake: Add support for standard variable BUILD_SHARED_LIBS
+            #457  Unexpose symbol _INTERNAL_trim_to_complete_utf8_characters
+            #467  Resolve macro HAVE_EXPAT_CONFIG_H
+            #472  Delete unused legacy helper file "conftools/PrintPath"
+       #473 #483  Improve attribution
+  #464 #465 #477  doc/reference.html: Fix XHTML validity
+       #475 #478  doc/reference.html: Replace the 90s look by OK.css
+            #479  Version info bumped from 8:0:7 to 9:0:8
+                    due to addition of new symbols and error codes;
+                    see https://verbump.de/ for what these numbers do
+
+        Infrastructure:
+            #456  CI: Enable periodic runs
+            #457  CI: Start covering the list of exported symbols
+            #474  CI: Isolate coverage task
+       #476 #482  CI: Adapt to breaking changes in image "ubuntu-18.04"
+            #477  CI: Cover well-formedness and DocBook/XHTML validity
+                    of doc/reference.html and doc/xmlwf.xml
+
+        Special thanks to:
+            Dimitry Andric
+            Eero Helenius
+            Nick Wellnhofer
+            Rhodri James
+            Tomas Korbar
+            Yury Gribov
+                 and
+            Clang LeakSan
+            JetBrains
+            OSS-Fuzz
+
+Release 2.3.0 Thu March 25 2021
+        Bug fixes:
+            #438  When calling XML_ParseBuffer without a prior successful call to
+                    XML_GetBuffer as a user, no longer trigger undefined behavior
+                    (by adding an integer to a NULL pointer) but rather return
+                    XML_STATUS_ERROR and set the error code to (new) code
+                    XML_ERROR_NO_BUFFER. Found by UBSan (UndefinedBehaviorSanitizer)
+                    of Clang 11 (but not Clang 9).
+            #444  xmlwf: Exit status 2 was used for both:
+                    - malformed input files (documented) and
+                    - invalid command-line arguments (undocumented).
+                    The case of invalid command-line arguments now
+                    has its own exit status 4, resolving the ambiguity.
+
+        Other changes:
+            #439  xmlwf: Add argument -k to allow continuing after
+                    non-fatal errors
+            #439  xmlwf: Add section about exit status to the -h help output
+  #422 #426 #447  Windows: Drop support for Visual Studio <=14.0/2015
+            #434  Windows: CMake: Detect unsupported Visual Studio at
+                    configure time (rather than at compile time)
+       #382 #428  testrunner: Make verbose mode (argument "-v") report
+                    about passed tests, and make default mode report about
+                    failures, as well.
+            #442  CMake: Call "enable_language(CXX)" prior to tinkering
+                    with CMAKE_CXX_* variables
+            #448  Document use of libexpat from a CMake-based project
+            #451  Autotools: Install CMake files as generated by CMake 3.19.6
+                    so that users with "find_package(expat [..] CONFIG [..])"
+                    are served on distributions that are *not* using the CMake
+                    build system inside for libexpat packaging
+       #436 #437  Autotools: Drop obsolescent macro AC_HEADER_STDC
+       #450 #452  Autotools: Resolve use of obsolete macro AC_CONFIG_HEADER
+            #441  Address compiler warnings
+            #443  Version info bumped from 7:12:6 to 8:0:7
+                    due to addition of error code XML_ERROR_NO_BUFFER
+                    (see https://verbump.de/ for what these numbers do)
+
+        Infrastructure:
+       #435 #446  Replace Travis CI by GitHub Actions
+
+        Special thanks to:
+            Alexander Richardson
+            Oleksandr Popovych
+            Thomas Beutlich
+            Tim Bray
+                 and
+            Clang LeakSan, Clang 11 UBSan and the Clang team
+
+Release 2.2.10 Sat October 3 2020
+        Bug fixes:
+  #390 #395 #398  Fix undefined behavior during parsing caused by
+                    pointer arithmetic with NULL pointers
+       #404 #405  Fix reading uninitialized variable during parsing
+            #406  xmlwf: Add missing check for malloc NULL return
+
+        Other changes:
+            #396  Windows: Drop support for Visual Studio <=8.0/2005
+            #409  Windows: Add missing file "Changes" to the installer
+                    to fix compilation with CMake from installed sources
+            #403  xmlwf: Document exit codes in xmlwf manpage and
+                    exit with code 3 (rather than code 1) for output errors
+                    when used with "-d DIRECTORY"
+       #356 #359  MinGW: Provide declaration of rand_s for mingwrt <5.3.0
+       #383 #392  Autotools: Use -Werror while configure tests the compiler
+                    for supported compile flags to avoid false positives
+  #383 #393 #394  Autotools: Improve handling of user (C|CPP|CXX|LD)FLAGS,
+                    e.g. ensure that they have the last word over flags added
+                    while running ./configure
+            #360  CMake: Create libexpatw.{dll,so} and expatw.pc (with emphasis
+                    on suffix "w") with -DEXPAT_CHAR_TYPE=(ushort|wchar_t)
+            #360  CMake: Detect and deny unsupported build combinations
+                    involving -DEXPAT_CHAR_TYPE=(ushort|wchar_t)
+            #360  CMake: Install pre-compiled shipped xmlwf.1 manpage in case
+                    of -DEXPAT_BUILD_DOCS=OFF
+  #375 #380 #419  CMake: Fix use of Expat by means of add_subdirectory
+       #407 #408  CMake: Keep expat target name constant at "expat"
+                    (i.e. refrain from using the target name to control
+                    build artifact filenames)
+            #385  CMake: Fix compilation with -DEXPAT_SHARED_LIBS=OFF for
+                    Windows
+                  CMake: Expose man page compilation as target "xmlwf-manpage"
+       #413 #414  CMake: Introduce option EXPAT_BUILD_PKGCONFIG
+                    to control generation of pkg-config file "expat.pc"
+            #424  CMake: Add minimalistic support for building binary packages
+                    with CMake target "package"; based on CPack
+            #366  CMake: Add option -DEXPAT_OSSFUZZ_BUILD=(ON|OFF) with
+                    default OFF to build fuzzer code against OSS-Fuzz and
+                    related environment variable LIB_FUZZING_ENGINE
+            #354  Fix testsuite for -DEXPAT_DTD=OFF and -DEXPAT_NS=OFF, each
+    #354 #355 ..
+       #356 #412  Address compiler warnings
+       #368 #369  Address pngcheck warnings with doc/*.png images
+            #425  Version info bumped from 7:11:6 to 7:12:6
+
+        Special thanks to:
+            asavah
+            Ben Wagner
+            Bhargava Shastry
+            Frank Landgraf
+            Jeffrey Walton
+            Joe Orton
+            Kleber Tarcísio
+            Ma Lin
+            Maciej Sroczyński
+            Mohammed Khajapasha
+            Vadim Zeitlin
+                 and
+            Cppcheck 2.0 and the Cppcheck team
+
+Release 2.2.9 Wed September 25 2019
         Other changes:
                   examples: Drop executable bits from elements.c
             #349  Windows: Change the name of the Windows DLLs from expat*.dll
@@ -17,7 +293,7 @@ Release 2.2.9 Wed Septemper 25 2019
         Special thanks to:
             Ben Wagner
 
-Release 2.2.8 Fri Septemper 13 2019
+Release 2.2.8 Fri September 13 2019
         Security fixes:
        #317 #318  CVE-2019-15903 -- Fix heap overflow triggered by
                     XML_GetCurrentLineNumber (or XML_GetCurrentColumnNumber),
@@ -115,10 +391,10 @@ Release 2.2.8 Fri Septemper 13 2019
         Special thanks to:
             David Loffredo
             Joonun Jang
-            Khajapasha Mohammed
             Kishore Kunche
             Marco Maggi
             Mitch Phillips
+            Mohammed Khajapasha
             Rolf Ade
             xantares
             Zhongyuan Zhou
diff --git a/contrib/expat/Makefile.am b/contrib/expat/Makefile.am
index 5e1d37dd1a83..e6e7971ec8b5 100644
--- a/contrib/expat/Makefile.am
+++ b/contrib/expat/Makefile.am
@@ -6,7 +6,8 @@
 #                      \___/_/\_\ .__/ \__,_|\__|
 #                               |_| XML parser
 #
-# Copyright (c) 2017 Expat development team
+# Copyright (c) 2017-2021 Sebastian Pipping <sebastian@pipping.org>
+# Copyright (c) 2018      KangLin <kl222@126.com>
 # Licensed under the MIT license:
 #
 # Permission is  hereby granted,  free of charge,  to any  person obtaining
@@ -53,13 +54,28 @@ pkgconfig_DATA = expat.pc
 pkgconfigdir = $(libdir)/pkgconfig
 
 
+dist_cmake_DATA = \
+    cmake/autotools/expat.cmake
+
+nodist_cmake_DATA = \
+    cmake/autotools/expat-config-version.cmake \
+    cmake/autotools/expat-noconfig.cmake \
+    cmake/expat-config.cmake
+
+cmakedir = $(libdir)/cmake/expat-@PACKAGE_VERSION@
+
+
 _EXTRA_DIST_CMAKE = \
-    cmake/expat-config.cmake.in \
+    cmake/autotools/expat-noconfig__linux.cmake.in \
+    cmake/autotools/expat-noconfig__macos.cmake.in \
+    cmake/autotools/expat-noconfig__windows.cmake.in \
+    cmake/autotools/expat-package-init.cmake \
     cmake/mingw-toolchain.cmake \
     \
     CMakeLists.txt \
     CMake.README \
     ConfigureChecks.cmake \
+    expat.pc.cmake \
     expat_config.h.cmake
 
 _EXTRA_DIST_WINDOWS = \
@@ -74,11 +90,14 @@ EXTRA_DIST = \
     \
     conftools/expat.m4 \
     conftools/get-version.sh \
-    conftools/PrintPath \
+    \
+    fuzz/xml_parsebuffer_fuzzer.c \
+    fuzz/xml_parse_fuzzer.c \
     \
     xmlwf/xmlwf_helpgen.py \
     xmlwf/xmlwf_helpgen.sh \
     \
+    buildconf.sh \
     Changes \
     README.md \
     \
diff --git a/contrib/expat/Makefile.in b/contrib/expat/Makefile.in
index 89bf68febc48..34f900a61630 100644
--- a/contrib/expat/Makefile.in
+++ b/contrib/expat/Makefile.in
@@ -1,7 +1,7 @@
-# Makefile.in generated by automake 1.16.1 from Makefile.am.
+# Makefile.in generated by automake 1.16.5 from Makefile.am.
 # @configure_input@
 
-# Copyright (C) 1994-2018 Free Software Foundation, Inc.
+# Copyright (C) 1994-2021 Free Software Foundation, Inc.
 
 # This Makefile.in is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
@@ -22,7 +22,8 @@
 #                      \___/_/\_\ .__/ \__,_|\__|
 #                               |_| XML parser
 #
-# Copyright (c) 2017 Expat development team
+# Copyright (c) 2017-2021 Sebastian Pipping <sebastian@pipping.org>
+# Copyright (c) 2018      KangLin <kl222@126.com>
 # Licensed under the MIT license:
 #
 # Permission is  hereby granted,  free of charge,  to any  person obtaining
@@ -138,12 +139,14 @@ am__aclocal_m4_deps = $(top_srcdir)/m4/libtool.m4 \
 am__configure_deps = $(am__aclocal_m4_deps) $(CONFIGURE_DEPENDENCIES) \
 	$(ACLOCAL_M4)
 DIST_COMMON = $(srcdir)/Makefile.am $(top_srcdir)/configure \
-	$(am__configure_deps) $(am__DIST_COMMON)
+	$(am__configure_deps) $(dist_cmake_DATA) $(am__DIST_COMMON)
 am__CONFIG_DISTCLEAN_FILES = config.status config.cache config.log \
  configure.lineno config.status.lineno
 mkinstalldirs = $(install_sh) -d
 CONFIG_HEADER = expat_config.h
-CONFIG_CLEAN_FILES = expat.pc run.sh
+CONFIG_CLEAN_FILES = expat.pc cmake/expat-config.cmake \
+	cmake/autotools/expat-config-version.cmake \
+	cmake/autotools/expat-noconfig.cmake run.sh
 CONFIG_CLEAN_VPATH_FILES =
 AM_V_P = $(am__v_P_@AM_V@)
 am__v_P_ = $(am__v_P_@AM_DEFAULT_V@)
@@ -199,8 +202,9 @@ am__uninstall_files_from_dir = { \
     || { echo " ( cd '$$dir' && rm -f" $$files ")"; \
          $(am__cd) "$$dir" && rm -f $$files; }; \
   }
-am__installdirs = "$(DESTDIR)$(pkgconfigdir)"
-DATA = $(pkgconfig_DATA)
+am__installdirs = "$(DESTDIR)$(cmakedir)" "$(DESTDIR)$(cmakedir)" \
+	"$(DESTDIR)$(pkgconfigdir)"
+DATA = $(dist_cmake_DATA) $(nodist_cmake_DATA) $(pkgconfig_DATA)
 RECURSIVE_CLEAN_TARGETS = mostlyclean-recursive clean-recursive	\
   distclean-recursive maintainer-clean-recursive
 am__recursive_targets = \
@@ -209,8 +213,8 @@ am__recursive_targets = \
   $(am__extra_recursive_targets)
 AM_RECURSIVE_TARGETS = $(am__recursive_targets:-recursive=) TAGS CTAGS \
 	cscope distdir distdir-am dist dist-all distcheck
-am__tagged_files = $(HEADERS) $(SOURCES) $(TAGS_FILES) \
-	$(LISP)expat_config.h.in
+am__tagged_files = $(HEADERS) $(SOURCES) $(TAGS_FILES) $(LISP) \
+	expat_config.h.in
 # Read a list of newline-separated strings from the standard input,
 # and print each of them once, without duplicates.  Input order is
 # *not* preserved.
@@ -227,18 +231,17 @@ am__define_uniq_tagged_files = \
   unique=`for i in $$list; do \
     if test -f "$$i"; then echo $$i; else echo $(srcdir)/$$i; fi; \
   done | $(am__uniquify_input)`
-ETAGS = etags
-CTAGS = ctags
-CSCOPE = cscope
 DIST_SUBDIRS = lib examples tests xmlwf doc
 am__DIST_COMMON = $(srcdir)/Makefile.in $(srcdir)/expat.pc.in \
 	$(srcdir)/expat_config.h.in $(srcdir)/run.sh.in \
+	$(top_srcdir)/cmake/autotools/expat-config-version.cmake.in \
+	$(top_srcdir)/cmake/expat-config.cmake.in \
 	$(top_srcdir)/conftools/ar-lib $(top_srcdir)/conftools/compile \
 	$(top_srcdir)/conftools/config.guess \
 	$(top_srcdir)/conftools/config.sub \
 	$(top_srcdir)/conftools/install-sh \
 	$(top_srcdir)/conftools/ltmain.sh \
-	$(top_srcdir)/conftools/missing AUTHORS COPYING \
+	$(top_srcdir)/conftools/missing AUTHORS COPYING README.md \
 	conftools/ar-lib conftools/compile conftools/config.guess \
 	conftools/config.sub conftools/depcomp conftools/install-sh \
 	conftools/ltmain.sh conftools/missing
@@ -281,13 +284,19 @@ DIST_ARCHIVES = $(distdir).tar.gz $(distdir).tar.bz2 $(distdir).tar.lz \
 	$(distdir).tar.xz
 GZIP_ENV = --best
 DIST_TARGETS = dist-lzip dist-xz dist-bzip2 dist-gzip
+# Exists only to be overridden by the user if desired.
+AM_DISTCHECK_DVI_TARGET = dvi
 distuninstallcheck_listfiles = find . -type f -print
 am__distuninstallcheck_listfiles = $(distuninstallcheck_listfiles) \
   | sed 's|^\./|$(prefix)/|' | grep -v '$(infodir)/dir$$'
 distcleancheck_listfiles = find . -type f -print
 ACLOCAL = @ACLOCAL@
 AMTAR = @AMTAR@
+AM_CFLAGS = @AM_CFLAGS@
+AM_CPPFLAGS = @AM_CPPFLAGS@
+AM_CXXFLAGS = @AM_CXXFLAGS@
 AM_DEFAULT_VERBOSITY = @AM_DEFAULT_VERBOSITY@
+AM_LDFLAGS = @AM_LDFLAGS@
 AR = @AR@
 AS = @AS@
 AUTOCONF = @AUTOCONF@
@@ -297,8 +306,9 @@ AWK = @AWK@
 CC = @CC@
 CCDEPMODE = @CCDEPMODE@
 CFLAGS = @CFLAGS@
-CPP = @CPP@
 CPPFLAGS = @CPPFLAGS@
+CSCOPE = @CSCOPE@
+CTAGS = @CTAGS@
 CXX = @CXX@
 CXXCPP = @CXXCPP@
 CXXDEPMODE = @CXXDEPMODE@
@@ -314,7 +324,15 @@ ECHO_C = @ECHO_C@
 ECHO_N = @ECHO_N@
 ECHO_T = @ECHO_T@
 EGREP = @EGREP@
+ETAGS = @ETAGS@
 EXEEXT = @EXEEXT@
+EXPAT_ATTR_INFO = @EXPAT_ATTR_INFO@
+EXPAT_CHAR_TYPE = @EXPAT_CHAR_TYPE@
+EXPAT_CONTEXT_BYTES = @EXPAT_CONTEXT_BYTES@
+EXPAT_DTD = @EXPAT_DTD@
+EXPAT_LARGE_SIZE = @EXPAT_LARGE_SIZE@
+EXPAT_MIN_SIZE = @EXPAT_MIN_SIZE@
+EXPAT_NS = @EXPAT_NS@
 FGREP = @FGREP@
 FILEMAP = @FILEMAP@
 GREP = @GREP@
@@ -327,6 +345,8 @@ LD = @LD@
 LDFLAGS = @LDFLAGS@
 LIBAGE = @LIBAGE@
 LIBCURRENT = @LIBCURRENT@
+LIBDIR_BASENAME = @LIBDIR_BASENAME@
+LIBM = @LIBM@
 LIBOBJS = @LIBOBJS@
 LIBREVISION = @LIBREVISION@
 LIBS = @LIBS@
@@ -356,6 +376,9 @@ RANLIB = @RANLIB@
 SED = @SED@
 SET_MAKE = @SET_MAKE@
 SHELL = @SHELL@
+SO_MAJOR = @SO_MAJOR@
+SO_MINOR = @SO_MINOR@
+SO_PATCH = @SO_PATCH@
 STRIP = @STRIP@
 VERSION = @VERSION@
 abs_builddir = @abs_builddir@
@@ -366,6 +389,7 @@ ac_ct_AR = @ac_ct_AR@
 ac_ct_CC = @ac_ct_CC@
 ac_ct_CXX = @ac_ct_CXX@
 ac_ct_DUMPBIN = @ac_ct_DUMPBIN@
+ac_cv_sizeof_void_p = @ac_cv_sizeof_void_p@
 am__include = @am__include@
 am__leading_dot = @am__leading_dot@
 am__quote = @am__quote@
@@ -403,6 +427,7 @@ pdfdir = @pdfdir@
 prefix = @prefix@
 program_transform_name = @program_transform_name@
 psdir = @psdir@
+runstatedir = @runstatedir@
 sbindir = @sbindir@
 sharedstatedir = @sharedstatedir@
 srcdir = @srcdir@
@@ -423,13 +448,26 @@ LIBTOOLFLAGS = --verbose
 SUBDIRS = lib $(am__append_1) $(am__append_2) $(am__append_3)
 pkgconfig_DATA = expat.pc
 pkgconfigdir = $(libdir)/pkgconfig
+dist_cmake_DATA = \
+    cmake/autotools/expat.cmake
+
+nodist_cmake_DATA = \
+    cmake/autotools/expat-config-version.cmake \
+    cmake/autotools/expat-noconfig.cmake \
+    cmake/expat-config.cmake
+
+cmakedir = $(libdir)/cmake/expat-@PACKAGE_VERSION@
 _EXTRA_DIST_CMAKE = \
-    cmake/expat-config.cmake.in \
+    cmake/autotools/expat-noconfig__linux.cmake.in \
+    cmake/autotools/expat-noconfig__macos.cmake.in \
+    cmake/autotools/expat-noconfig__windows.cmake.in \
+    cmake/autotools/expat-package-init.cmake \
     cmake/mingw-toolchain.cmake \
     \
     CMakeLists.txt \
     CMake.README \
     ConfigureChecks.cmake \
+    expat.pc.cmake \
     expat_config.h.cmake
 
 _EXTRA_DIST_WINDOWS = \
@@ -444,11 +482,14 @@ EXTRA_DIST = \
     \
     conftools/expat.m4 \
     conftools/get-version.sh \
-    conftools/PrintPath \
+    \
+    fuzz/xml_parsebuffer_fuzzer.c \
+    fuzz/xml_parse_fuzzer.c \
     \
     xmlwf/xmlwf_helpgen.py \
     xmlwf/xmlwf_helpgen.sh \
     \
+    buildconf.sh \
     Changes \
     README.md \
     \
@@ -509,6 +550,12 @@ distclean-hdr:
 	-rm -f expat_config.h stamp-h1
 expat.pc: $(top_builddir)/config.status $(srcdir)/expat.pc.in
 	cd $(top_builddir) && $(SHELL) ./config.status $@
+cmake/expat-config.cmake: $(top_builddir)/config.status $(top_srcdir)/cmake/expat-config.cmake.in
+	cd $(top_builddir) && $(SHELL) ./config.status $@
+cmake/autotools/expat-config-version.cmake: $(top_builddir)/config.status $(top_srcdir)/cmake/autotools/expat-config-version.cmake.in
+	cd $(top_builddir) && $(SHELL) ./config.status $@
+cmake/autotools/expat-noconfig.cmake: $(top_builddir)/config.status 
+	cd $(top_builddir) && $(SHELL) ./config.status $@
 run.sh: $(top_builddir)/config.status $(srcdir)/run.sh.in
 	cd $(top_builddir) && $(SHELL) ./config.status $@
 
@@ -520,6 +567,48 @@ clean-libtool:
 
 distclean-libtool:
 	-rm -f libtool config.lt
+install-dist_cmakeDATA: $(dist_cmake_DATA)
+	@$(NORMAL_INSTALL)
+	@list='$(dist_cmake_DATA)'; test -n "$(cmakedir)" || list=; \
+	if test -n "$$list"; then \
+	  echo " $(MKDIR_P) '$(DESTDIR)$(cmakedir)'"; \
+	  $(MKDIR_P) "$(DESTDIR)$(cmakedir)" || exit 1; \
+	fi; \
+	for p in $$list; do \
+	  if test -f "$$p"; then d=; else d="$(srcdir)/"; fi; \
+	  echo "$$d$$p"; \
+	done | $(am__base_list) | \
+	while read files; do \
+	  echo " $(INSTALL_DATA) $$files '$(DESTDIR)$(cmakedir)'"; \
+	  $(INSTALL_DATA) $$files "$(DESTDIR)$(cmakedir)" || exit $$?; \
+	done
+
+uninstall-dist_cmakeDATA:
+	@$(NORMAL_UNINSTALL)
+	@list='$(dist_cmake_DATA)'; test -n "$(cmakedir)" || list=; \
+	files=`for p in $$list; do echo $$p; done | sed -e 's|^.*/||'`; \
+	dir='$(DESTDIR)$(cmakedir)'; $(am__uninstall_files_from_dir)
+install-nodist_cmakeDATA: $(nodist_cmake_DATA)
+	@$(NORMAL_INSTALL)
+	@list='$(nodist_cmake_DATA)'; test -n "$(cmakedir)" || list=; \
+	if test -n "$$list"; then \
+	  echo " $(MKDIR_P) '$(DESTDIR)$(cmakedir)'"; \
+	  $(MKDIR_P) "$(DESTDIR)$(cmakedir)" || exit 1; \
+	fi; \
+	for p in $$list; do \
+	  if test -f "$$p"; then d=; else d="$(srcdir)/"; fi; \
+	  echo "$$d$$p"; \
+	done | $(am__base_list) | \
+	while read files; do \
+	  echo " $(INSTALL_DATA) $$files '$(DESTDIR)$(cmakedir)'"; \
+	  $(INSTALL_DATA) $$files "$(DESTDIR)$(cmakedir)" || exit $$?; \
+	done
+
+uninstall-nodist_cmakeDATA:
+	@$(NORMAL_UNINSTALL)
+	@list='$(nodist_cmake_DATA)'; test -n "$(cmakedir)" || list=; \
+	files=`for p in $$list; do echo $$p; done | sed -e 's|^.*/||'`; \
+	dir='$(DESTDIR)$(cmakedir)'; $(am__uninstall_files_from_dir)
 install-pkgconfigDATA: $(pkgconfig_DATA)
 	@$(NORMAL_INSTALL)
 	@list='$(pkgconfig_DATA)'; test -n "$(pkgconfigdir)" || list=; \
@@ -647,7 +736,6 @@ cscopelist-am: $(am__tagged_files)
 distclean-tags:
 	-rm -f TAGS ID GTAGS GRTAGS GSYMS GPATH tags
 	-rm -f cscope.out cscope.in.out cscope.po.out cscope.files
-
 distdir: $(BUILT_SOURCES)
 	$(MAKE) $(AM_MAKEFLAGS) distdir-am
 
@@ -728,6 +816,10 @@ dist-xz: distdir
 	tardir=$(distdir) && $(am__tar) | XZ_OPT=$${XZ_OPT--e} xz -c >$(distdir).tar.xz
 	$(am__post_remove_distdir)
 
+dist-zstd: distdir
+	tardir=$(distdir) && $(am__tar) | zstd -c $${ZSTD_CLEVEL-$${ZSTD_OPT--19}} >$(distdir).tar.zst
+	$(am__post_remove_distdir)
+
 dist-tarZ: distdir
 	@echo WARNING: "Support for distribution archives compressed with" \
 		       "legacy program 'compress' is deprecated." >&2
@@ -770,6 +862,8 @@ distcheck: dist
 	  eval GZIP= gzip $(GZIP_ENV) -dc $(distdir).shar.gz | unshar ;;\
 	*.zip*) \
 	  unzip $(distdir).zip ;;\
+	*.tar.zst*) \
+	  zstd -dc $(distdir).tar.zst | $(am__untar) ;;\
 	esac
 	chmod -R a-w $(distdir)
 	chmod u+w $(distdir)
@@ -785,7 +879,7 @@ distcheck: dist
 	    $(DISTCHECK_CONFIGURE_FLAGS) \
 	    --srcdir=../.. --prefix="$$dc_install_base" \
 	  && $(MAKE) $(AM_MAKEFLAGS) \
-	  && $(MAKE) $(AM_MAKEFLAGS) dvi \
+	  && $(MAKE) $(AM_MAKEFLAGS) $(AM_DISTCHECK_DVI_TARGET) \
 	  && $(MAKE) $(AM_MAKEFLAGS) check \
 	  && $(MAKE) $(AM_MAKEFLAGS) install \
 	  && $(MAKE) $(AM_MAKEFLAGS) installcheck \
@@ -841,7 +935,7 @@ check: check-recursive
 all-am: Makefile $(DATA) expat_config.h
 installdirs: installdirs-recursive
 installdirs-am:
-	for dir in "$(DESTDIR)$(pkgconfigdir)"; do \
+	for dir in "$(DESTDIR)$(cmakedir)" "$(DESTDIR)$(cmakedir)" "$(DESTDIR)$(pkgconfigdir)"; do \
 	  test -z "$$dir" || $(MKDIR_P) "$$dir"; \
 	done
 install: install-recursive
@@ -896,7 +990,8 @@ info: info-recursive
 
 info-am:
 
-install-data-am: install-pkgconfigDATA
+install-data-am: install-dist_cmakeDATA install-nodist_cmakeDATA \
+	install-pkgconfigDATA
 
 install-dvi: install-dvi-recursive
 
@@ -942,7 +1037,8 @@ ps: ps-recursive
 
 ps-am:
 
-uninstall-am: uninstall-pkgconfigDATA
+uninstall-am: uninstall-dist_cmakeDATA uninstall-nodist_cmakeDATA \
+	uninstall-pkgconfigDATA
 
 .MAKE: $(am__recursive_targets) all install-am install-strip
 
@@ -950,18 +1046,21 @@ uninstall-am: uninstall-pkgconfigDATA
 	am--refresh check check-am clean clean-cscope clean-generic \
 	clean-libtool cscope cscopelist-am ctags ctags-am dist \
 	dist-all dist-bzip2 dist-gzip dist-lzip dist-shar dist-tarZ \
-	dist-xz dist-zip distcheck distclean distclean-generic \
-	distclean-hdr distclean-libtool distclean-tags distcleancheck \
-	distdir distuninstallcheck dvi dvi-am html html-am info \
-	info-am install install-am install-data install-data-am \
+	dist-xz dist-zip dist-zstd distcheck distclean \
+	distclean-generic distclean-hdr distclean-libtool \
+	distclean-tags distcleancheck distdir distuninstallcheck dvi \
+	dvi-am html html-am info info-am install install-am \
+	install-data install-data-am install-dist_cmakeDATA \
 	install-dvi install-dvi-am install-exec install-exec-am \
 	install-html install-html-am install-info install-info-am \
-	install-man install-pdf install-pdf-am install-pkgconfigDATA \
-	install-ps install-ps-am install-strip installcheck \
-	installcheck-am installdirs installdirs-am maintainer-clean \
-	maintainer-clean-generic mostlyclean mostlyclean-generic \
-	mostlyclean-libtool pdf pdf-am ps ps-am tags tags-am uninstall \
-	uninstall-am uninstall-pkgconfigDATA
+	install-man install-nodist_cmakeDATA install-pdf \
+	install-pdf-am install-pkgconfigDATA install-ps install-ps-am \
+	install-strip installcheck installcheck-am installdirs \
+	installdirs-am maintainer-clean maintainer-clean-generic \
+	mostlyclean mostlyclean-generic mostlyclean-libtool pdf pdf-am \
+	ps ps-am tags tags-am uninstall uninstall-am \
+	uninstall-dist_cmakeDATA uninstall-nodist_cmakeDATA \
+	uninstall-pkgconfigDATA
 
 .PRECIOUS: Makefile
 
diff --git a/contrib/expat/README.md b/contrib/expat/README.md
index 1cc52b014489..6fdd6148714b 100644
--- a/contrib/expat/README.md
+++ b/contrib/expat/README.md
@@ -1,12 +1,14 @@
-[![Travis CI Build Status](https://travis-ci.org/libexpat/libexpat.svg?branch=master)](https://travis-ci.org/libexpat/libexpat)
+[![Run Linux Travis CI tasks](https://github.com/libexpat/libexpat/actions/workflows/linux.yml/badge.svg)](https://github.com/libexpat/libexpat/actions/workflows/linux.yml)
 [![AppVeyor Build Status](https://ci.appveyor.com/api/projects/status/github/libexpat/libexpat?svg=true)](https://ci.appveyor.com/project/libexpat/libexpat)
 [![Packaging status](https://repology.org/badge/tiny-repos/expat.svg)](https://repology.org/metapackage/expat/versions)
+[![Downloads SourceForge](https://img.shields.io/sourceforge/dt/expat?label=Downloads%20SourceForge)](https://sourceforge.net/projects/expat/files/)
+[![Downloads GitHub](https://img.shields.io/github/downloads/libexpat/libexpat/total?label=Downloads%20GitHub)](https://github.com/libexpat/libexpat/releases)
 
 
-# Expat, Release 2.2.9
+# Expat, Release 2.4.3
 
 This is Expat, a C library for parsing XML, started by
-[James Clark](https://en.wikipedia.org/wiki/James_Clark_(programmer)) in 1997.
+[James Clark](https://en.wikipedia.org/wiki/James_Clark_%28programmer%29) in 1997.
 Expat is a stream-oriented XML parser.  This means that you register
 handlers with the parser before starting the parse.  These handlers
 are called when the parser discovers the associated structures in the
@@ -14,13 +16,14 @@ document being parsed.  A start tag is an example of the kind of
 structures for which you may register handlers.
 
 Expat supports the following compilers:
+
 - GNU GCC >=4.5
 - LLVM Clang >=3.5
-- Microsoft Visual Studio >=8.0/2005
+- Microsoft Visual Studio >=15.0/2017 (rolling `${today} minus 5 years`)
 
-Windows users should use the
-[`expat_win32` package](https://sourceforge.net/projects/expat/files/expat_win32/),
-which includes both precompiled libraries and executables, and source code for
+Windows users can use the
+[`expat-win32bin-*.*.*.{exe,zip}` download](https://github.com/libexpat/libexpat/releases),
+which includes both pre-compiled libraries and executables, and source code for
 developers.
 
 Expat is [free software](https://www.gnu.org/philosophy/free-sw.en.html).
@@ -30,6 +33,67 @@ contained in the file
 distributed with this package.
 This license is the same as the MIT/X Consortium license.
 
+
+## Using libexpat in your CMake-Based Project
+
+There are two ways of using libexpat with CMake:
+
+### a) Module Mode
+
+This approach leverages CMake's own [module `FindEXPAT`](https://cmake.org/cmake/help/latest/module/FindEXPAT.html).
+
+Notice the *uppercase* `EXPAT` in the following example:
+
+```cmake
+cmake_minimum_required(VERSION 3.0)  # or 3.10, see below
+
+project(hello VERSION 1.0.0)
+
+find_package(EXPAT 2.2.8 MODULE REQUIRED)
+
+add_executable(hello
+    hello.c
+)
+
+# a) for CMake >=3.10 (see CMake's FindEXPAT docs)
+target_link_libraries(hello PUBLIC EXPAT::EXPAT)
+
+# b) for CMake >=3.0
+target_include_directories(hello PRIVATE ${EXPAT_INCLUDE_DIRS})
+target_link_libraries(hello PUBLIC ${EXPAT_LIBRARIES})
+```
+
+### b) Config Mode
+
+This approach requires files from…
+
+- libexpat >=2.2.8 where packaging uses the CMake build system
+or
+- libexpat >=2.3.0 where packaging uses the GNU Autotools build system
+  on Linux
+or
+- libexpat >=2.4.0 where packaging uses the GNU Autotools build system
+  on macOS or MinGW.
+
+Notice the *lowercase* `expat` in the following example:
+
+```cmake
+cmake_minimum_required(VERSION 3.0)
+
+project(hello VERSION 1.0.0)
+
+find_package(expat 2.2.8 CONFIG REQUIRED char dtd ns)
+
+add_executable(hello
+    hello.c
+)
+
+target_link_libraries(hello PUBLIC expat::expat)
+```
+
+
+## Building from a Git Clone
+
 If you are building Expat from a check-out from the
 [Git repository](https://github.com/libexpat/libexpat/),
 you need to run a script that generates the configure script using the
@@ -43,6 +107,11 @@ autoconf 2.58 or newer. Run the script like this:
 Once this has been done, follow the same instructions as for building
 from a source distribution.
 
+
+## Building from a Source Distribution
+
+### a) Building with the configure script (i.e. GNU Autotools)
+
 To build Expat from a source distribution, you first run the
 configuration shell script in the top level distribution directory:
 
@@ -132,8 +201,14 @@ A reference manual is available in the file `doc/reference.html` in this
 distribution.
 
 
-The CMake build system is still *experimental* and will replace the primary
+### b) Building with CMake
+
+The CMake build system is still *experimental* and may replace the primary
 build system based on GNU Autotools at some point when it is ready.
+
+
+#### Available Options
+
 For an idea of the available (non-advanced) options for building with CMake:
 
 ```console
@@ -156,6 +231,9 @@ EXPAT_BUILD_EXAMPLES:BOOL=ON
 // build fuzzers for the expat library
 EXPAT_BUILD_FUZZERS:BOOL=OFF
 
+// build pkg-config file
+EXPAT_BUILD_PKGCONFIG:BOOL=ON
+
 // build the tests for expat library
 EXPAT_BUILD_TESTS:BOOL=ON
 
@@ -171,6 +249,9 @@ EXPAT_ENABLE_INSTALL:BOOL=ON
 // Use /MT flag (static CRT) when compiling in MSVC
 EXPAT_MSVC_STATIC_CRT:BOOL=OFF
 
+// build fuzzers via ossfuzz for the expat library
+EXPAT_OSSFUZZ_BUILD:BOOL=OFF
+
 // build a shared expat library
 EXPAT_SHARED_LIBS:BOOL=ON
 
diff --git a/contrib/expat/buildconf.sh b/contrib/expat/buildconf.sh
new file mode 100755
index 000000000000..5edbc565bc27
--- /dev/null
+++ b/contrib/expat/buildconf.sh
@@ -0,0 +1,55 @@
+#! /usr/bin/env bash
+#                          __  __            _
+#                       ___\ \/ /_ __   __ _| |_
+#                      / _ \\  /| '_ \ / _` | __|
+#                     |  __//  \| |_) | (_| | |_
+#                      \___/_/\_\ .__/ \__,_|\__|
+#                               |_| XML parser
+#
+# Copyright (c) 2017-2021 Sebastian Pipping <sebastian@pipping.org>
+# Copyright (c) 2018      Marco Maggi <marco.maggi-ipsu@poste.it>
+# Licensed under the MIT license:
+#
+# Permission is  hereby granted,  free of charge,  to any  person obtaining
+# a  copy  of  this  software   and  associated  documentation  files  (the
+# "Software"),  to  deal in  the  Software  without restriction,  including
+# without  limitation the  rights  to use,  copy,  modify, merge,  publish,
+# distribute, sublicense, and/or sell copies of the Software, and to permit
+# persons  to whom  the Software  is  furnished to  do so,  subject to  the
+# following conditions:
+#
+# The above copyright  notice and this permission notice  shall be included
+# in all copies or substantial portions of the Software.
+#
+# THE  SOFTWARE  IS  PROVIDED  "AS  IS",  WITHOUT  WARRANTY  OF  ANY  KIND,
+# EXPRESS  OR IMPLIED,  INCLUDING  BUT  NOT LIMITED  TO  THE WARRANTIES  OF
+# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+# NO EVENT SHALL THE AUTHORS OR  COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+# DAMAGES OR  OTHER LIABILITY, WHETHER  IN AN  ACTION OF CONTRACT,  TORT OR
+# OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+# USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+set -e
+
+# File expat_config.h.in (as generated by autoheader by autoreconf) contains
+# macro SIZEOF_VOID_P which is (1) not really needed by Expat as of today and
+# (2) a problem to "multilib" systems with one shared installed
+# /usr/include/expat_config.h for two Expats with different "void *" sizes
+# installed in e.g. /usr/lib32 and /usr/lib64.  Hence we patch macro
+# SIZEOF_VOID_P out of template expat_config.h.in so that configure will
+# not put SIZEOF_VOID_P in the eventual expat_config.h.
+patch_expat_config_h_in() {
+    local filename="$1"
+    local sizeof_void_p_line_number="$(fgrep -n SIZEOF_VOID_P "${filename}" | awk -F: '{print $1}')"
+    [[ ${sizeof_void_p_line_number} =~ ^[0-9]+$ ]]  # cheap assert
+    local first_line_to_delete=$(( sizeof_void_p_line_number - 1 ))
+    local last_line_to_delete=$(( sizeof_void_p_line_number + 1 ))
+    # Note: Avoiding "sed -i" only for macOS portability.
+    local tempfile="$(mktemp)"
+    sed "${first_line_to_delete},${last_line_to_delete}d" "${filename}" > "${tempfile}"
+    mv "${tempfile}" "${filename}"
+}
+
+autoreconf --warnings=all --install --verbose "$@"
+
+patch_expat_config_h_in expat_config.h.in
diff --git a/contrib/expat/configure.ac b/contrib/expat/configure.ac
index e2b9a1146286..c285a2b60ed7 100644
--- a/contrib/expat/configure.ac
+++ b/contrib/expat/configure.ac
@@ -1,21 +1,54 @@
 dnl   configuration script for expat
 dnl   Process this file with autoconf to produce a configure script.
+dnl                            __  __            _
+dnl                         ___\ \/ /_ __   __ _| |_
+dnl                        / _ \\  /| '_ \ / _` | __|
+dnl                       |  __//  \| |_) | (_| | |_
+dnl                        \___/_/\_\ .__/ \__,_|\__|
+dnl                                 |_| XML parser
 dnl
-dnl   Copyright 2000 Clark Cooper
+dnl   Copyright (c) 2000      Clark Cooper <coopercc@users.sourceforge.net>
+dnl   Copyright (c) 2000-2005 Fred L. Drake, Jr. <fdrake@users.sourceforge.net>
+dnl   Copyright (c) 2001-2003 Greg Stein <gstein@users.sourceforge.net>
+dnl   Copyright (c) 2006-2012 Karl Waclawek <karl@waclawek.net>
+dnl   Copyright (c) 2016-2022 Sebastian Pipping <sebastian@pipping.org>
+dnl   Copyright (c) 2017      S. P. Zeidler <spz@netbsd.org>
+dnl   Copyright (c) 2017      Stephen Groat <stephen@groat.us>
+dnl   Copyright (c) 2017-2020 Joe Orton <jorton@redhat.com>
+dnl   Copyright (c) 2018      Yury Gribov <tetra2005@gmail.com>
+dnl   Copyright (c) 2018      Benjamin Peterson <benjamin@python.org>
+dnl   Copyright (c) 2018      Marco Maggi <marco.maggi-ipsu@poste.it>
+dnl   Copyright (c) 2018      KangLin <kl222@126.com>
+dnl   Copyright (c) 2019      Mohammed Khajapasha <mohammed.khajapasha@intel.com>
+dnl   Copyright (c) 2019      Kishore Kunche <kishore.kunche@intel.com>
+dnl   Copyright (c) 2020      Jeffrey Walton <noloader@gmail.com>
+dnl   Licensed under the MIT license:
 dnl
-dnl   This file is part of EXPAT.
+dnl   Permission is  hereby granted,  free of charge,  to any  person obtaining
+dnl   a  copy  of  this  software   and  associated  documentation  files  (the
+dnl   "Software"),  to  deal in  the  Software  without restriction,  including
+dnl   without  limitation the  rights  to use,  copy,  modify, merge,  publish,
+dnl   distribute, sublicense, and/or sell copies of the Software, and to permit
+dnl   persons  to whom  the Software  is  furnished to  do so,  subject to  the
+dnl   following conditions:
 dnl
-dnl   EXPAT is free software; you can redistribute it and/or modify it
-dnl   under the terms of the License (based on the MIT/X license) contained
-dnl   in the file COPYING that comes with this distribution.
+dnl   The above copyright  notice and this permission notice  shall be included
+dnl   in all copies or substantial portions of the Software.
 dnl
+dnl   THE  SOFTWARE  IS  PROVIDED  "AS  IS",  WITHOUT  WARRANTY  OF  ANY  KIND,
+dnl   EXPRESS  OR IMPLIED,  INCLUDING  BUT  NOT LIMITED  TO  THE WARRANTIES  OF
+dnl   MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+dnl   NO EVENT SHALL THE AUTHORS OR  COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+dnl   DAMAGES OR  OTHER LIABILITY, WHETHER  IN AN  ACTION OF CONTRACT,  TORT OR
+dnl   OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+dnl   USE OR OTHER DEALINGS IN THE SOFTWARE.
 
 dnl Ensure that Expat is configured with autoconf 2.69 or newer.
-AC_PREREQ(2.69)
+AC_PREREQ([2.69])
 
 dnl Get the version number of Expat, using m4's esyscmd() command to run
 dnl the command at m4-generation time. This allows us to create an m4
-dnl symbol holding the correct version number. AC_INIT() requires the
+dnl symbol holding the correct version number. AC_INIT requires the
 dnl version number at m4-time, rather than when ./configure is run, so
 dnl all this must happen as part of m4, not as part of the shell code
 dnl contained in ./configure.
@@ -27,7 +60,7 @@ m4_define([expat_version],
   m4_ifdef([__gnu__],
            [esyscmd(conftools/get-version.sh lib/expat.h)],
            [2.2.x]))
-AC_INIT(expat, expat_version, expat-bugs@libexpat.org)
+AC_INIT([expat], expat_version, [expat-bugs@libexpat.org])
 m4_undefine([expat_version])
 
 AC_CONFIG_SRCDIR([Makefile.in])
@@ -48,12 +81,11 @@ dnl
 dnl If the API changes incompatibly set LIBAGE back to 0
 dnl
 
-LIBCURRENT=7    # sync
-LIBREVISION=11  # with
-LIBAGE=6        # CMakeLists.txt!
+LIBCURRENT=9   # sync
+LIBREVISION=3  # with
+LIBAGE=8       # CMakeLists.txt!
 
-AX_APPEND_FLAG([-DHAVE_EXPAT_CONFIG_H], [CPPFLAGS])
-AC_CONFIG_HEADER([expat_config.h])
+AC_CONFIG_HEADERS([expat_config.h])
 
 AM_PROG_AR
 AC_PROG_INSTALL
@@ -69,30 +101,32 @@ AC_SUBST(LIBAGE)
 
 AC_LANG([C])
 AC_PROG_CC_C99
+
 AS_IF([test "$GCC" = yes],
-  [AX_APPEND_COMPILE_FLAGS([-Wall -Wextra], [CFLAGS])
+  [AX_APPEND_COMPILE_FLAGS([-Wall -Wextra], [AM_CFLAGS])
    dnl Be careful about adding the -fexceptions option; some versions of
    dnl GCC don't support it and it causes extra warnings that are only
    dnl distracting; avoid.
-   AX_APPEND_COMPILE_FLAGS([-fexceptions], [CFLAGS])
-   AX_APPEND_COMPILE_FLAGS([-fno-strict-aliasing -Wmissing-prototypes -Wstrict-prototypes], [CFLAGS])
-   AX_APPEND_COMPILE_FLAGS([-pedantic -Wduplicated-cond -Wduplicated-branches -Wlogical-op], [CFLAGS])
-   AX_APPEND_COMPILE_FLAGS([-Wrestrict -Wnull-dereference -Wjump-misses-init -Wdouble-promotion], [CFLAGS])
-   AX_APPEND_COMPILE_FLAGS([-Wshadow -Wformat=2 -Wmisleading-indentation], [CFLAGS])])
+   AX_APPEND_COMPILE_FLAGS([-fexceptions], [AM_CFLAGS])
+   AX_APPEND_COMPILE_FLAGS([-fno-strict-aliasing -Wmissing-prototypes -Wstrict-prototypes], [AM_CFLAGS])
+   AX_APPEND_COMPILE_FLAGS([-pedantic -Wduplicated-cond -Wduplicated-branches -Wlogical-op], [AM_CFLAGS])
+   AX_APPEND_COMPILE_FLAGS([-Wrestrict -Wnull-dereference -Wjump-misses-init -Wdouble-promotion], [AM_CFLAGS])
+   AX_APPEND_COMPILE_FLAGS([-Wshadow -Wformat=2 -Wno-pedantic-ms-format -Wmisleading-indentation], [AM_CFLAGS])])
 
 AC_LANG_PUSH([C++])
 AC_PROG_CXX
+
 AS_IF([test "$GCC" = yes],
-  [AX_APPEND_COMPILE_FLAGS([-Wall -Wextra], [CXXFLAGS])
+  [AX_APPEND_COMPILE_FLAGS([-Wall -Wextra], [AM_CXXFLAGS])
    dnl Be careful about adding the -fexceptions option; some versions of
    dnl GCC don't support it and it causes extra warnings that are only
    dnl distracting; avoid.
-   AX_APPEND_COMPILE_FLAGS([-fexceptions], [CXXFLAGS])
-   AX_APPEND_COMPILE_FLAGS([-fno-strict-aliasing], [CXXFLAGS])])
+   AX_APPEND_COMPILE_FLAGS([-fexceptions], [AM_CXXFLAGS])
+   AX_APPEND_COMPILE_FLAGS([-fno-strict-aliasing], [AM_CXXFLAGS])])
 AC_LANG_POP([C++])
 
 AS_IF([test "$GCC" = yes],
-  [AX_APPEND_LINK_FLAGS([-fno-strict-aliasing],[LDFLAGS])])
+  [AX_APPEND_LINK_FLAGS([-fno-strict-aliasing],[AM_LDFLAGS])])
 
 dnl patching ${archive_cmds} to affect generation of file "libtool" to fix linking with clang (issue #312)
 AS_CASE(["$LD"],[*clang*],
@@ -100,11 +134,8 @@ AS_CASE(["$LD"],[*clang*],
      [*linux*],[archive_cmds='$CC -shared $pic_flag $libobjs $deplibs $compiler_flags $wl-soname $wl$soname -o $lib'])])
 
 EXPATCFG_COMPILER_SUPPORTS_VISIBILITY([
-  AX_APPEND_FLAG([-fvisibility=hidden],       [CFLAGS])
-  AX_APPEND_FLAG([-DXML_ENABLE_VISIBILITY=1], [CFLAGS])])
-
-dnl Checks for header files.
-AC_HEADER_STDC
+  AX_APPEND_FLAG([-fvisibility=hidden],       [AM_CFLAGS])
+  AX_APPEND_FLAG([-DXML_ENABLE_VISIBILITY=1], [AM_CPPFLAGS])])
 
 dnl Checks for typedefs, structures, and compiler characteristics.
 
@@ -149,8 +180,13 @@ AS_CASE("${host_os}",
    AC_MSG_NOTICE([detected OS: MinGW])])
 AM_CONDITIONAL([MINGW], [test x${EXPATCFG_ON_MINGW} = xyes])
 
+dnl Note: Prefix "_INTERNAL_" here means exclusive use inside of file configure.ac
 AM_CONDITIONAL([UNICODE], [echo -- "${CPPFLAGS}${CFLAGS}" | ${FGREP} XML_UNICODE >/dev/null])
+AM_CONDITIONAL([_INTERNAL_UNICODE_WCHAR_T], [echo -- "${CPPFLAGS}${CFLAGS}" | ${FGREP} XML_UNICODE_WCHAR_T >/dev/null])
+AM_CONDITIONAL([_INTERNAL_MIN_SIZE], [echo -- "${CPPFLAGS}${CFLAGS}" | ${FGREP} XML_MIN_SIZE >/dev/null])
+AM_CONDITIONAL([_INTERNAL_LARGE_SIZE], [echo -- "${CPPFLAGS}${CFLAGS}" | ${FGREP} XML_LARGE_SIZE >/dev/null])
 
+LT_LIB_M
 
 AC_ARG_WITH([libbsd],
   [AS_HELP_STRING([--with-libbsd], [utilize libbsd (for arc4random_buf)])],
@@ -307,8 +343,67 @@ AS_IF([test "x${DOCBOOK_TO_MAN}" != x -a "x$with_docbook" != xno],
 
 AM_CONDITIONAL(WITH_DOCBOOK, [test "x${DOCBOOK_TO_MAN}" != x])
 
+
+dnl Configure CMake file templates
+dnl NOTE: The *_TRUE variables read here are Automake conditionals
+dnl       that are either set to "" when enabled or to "#" when disabled
+dnl       (because they are used to dynamically comment out certain things)
+AS_IF([test "x${enable_xml_attr_info}" = xyes],
+  [EXPAT_ATTR_INFO=ON],
+  [EXPAT_ATTR_INFO=OFF])
+EXPAT_DTD=ON
+AS_IF([test "x${_INTERNAL_LARGE_SIZE_TRUE}" = x],
+  [EXPAT_LARGE_SIZE=ON],
+  [EXPAT_LARGE_SIZE=OFF])
+AS_IF([test "x${_INTERNAL_MIN_SIZE_TRUE}" = x],
+  [EXPAT_MIN_SIZE=ON],
+  [EXPAT_MIN_SIZE=OFF])
+EXPAT_NS=ON
+AS_IF([test "x${enable_xml_context}" != xno],
+  [EXPAT_CONTEXT_BYTES=${enable_xml_context}],
+  [EXPAT_CONTEXT_BYTES=OFF])
+AS_IF([test "x${UNICODE_TRUE}" = x],
+  [AS_IF(
+     [test "x${_INTERNAL_UNICODE_WCHAR_T_TRUE}" = x],
+        [EXPAT_CHAR_TYPE=wchar_t],
+        [EXPAT_CHAR_TYPE=ushort])],
+  [EXPAT_CHAR_TYPE=char])
+PACKAGE_INIT="${srcdir}"/cmake/autotools/expat-package-init.cmake
+LIBDIR_BASENAME="$(basename "${libdir}")"
+SO_MAJOR="$(expr "${LIBCURRENT}" - "${LIBAGE}")"
+SO_MINOR="${LIBAGE}"
+SO_PATCH="${LIBREVISION}"
+AC_CHECK_SIZEOF([void *])  # sets ac_cv_sizeof_void_p
+AC_SUBST([EXPAT_ATTR_INFO])
+AC_SUBST([EXPAT_DTD])
+AC_SUBST([EXPAT_LARGE_SIZE])
+AC_SUBST([EXPAT_MIN_SIZE])
+AC_SUBST([EXPAT_NS])
+AC_SUBST([EXPAT_CONTEXT_BYTES])
+AC_SUBST([EXPAT_CHAR_TYPE])
+AC_SUBST_FILE([PACKAGE_INIT])
+AC_SUBST([LIBDIR_BASENAME])
+AC_SUBST([SO_MAJOR])
+AC_SUBST([SO_MINOR])
+AC_SUBST([SO_PATCH])
+AC_SUBST([ac_cv_sizeof_void_p])
+
+
+dnl write the Automake flags we set
+AC_SUBST([AM_CPPFLAGS])
+AC_SUBST([AM_CFLAGS])
+AC_SUBST([AM_CXXFLAGS])
+AC_SUBST([AM_LDFLAGS])
+
+AS_CASE("${host_os}",
+  [darwin*], [CMAKE_NOCONFIG_SOURCE=cmake/autotools/expat-noconfig__macos.cmake.in],
+  [mingw*], [CMAKE_NOCONFIG_SOURCE=cmake/autotools/expat-noconfig__windows.cmake.in],
+  [CMAKE_NOCONFIG_SOURCE=cmake/autotools/expat-noconfig__linux.cmake.in])
 AC_CONFIG_FILES([Makefile]
   [expat.pc]
+  [cmake/expat-config.cmake]
+  [cmake/autotools/expat-config-version.cmake]
+  [cmake/autotools/expat-noconfig.cmake:${CMAKE_NOCONFIG_SOURCE}]
   [doc/Makefile]
   [examples/Makefile]
   [lib/Makefile]
@@ -317,3 +412,18 @@ AC_CONFIG_FILES([Makefile]
   [xmlwf/Makefile])
 AC_CONFIG_FILES([run.sh], [chmod +x run.sh])
 AC_OUTPUT
+
+
+AC_MSG_NOTICE([
+
+Automake flags (can be overridden by user flags):
+  [AM_CPPFLAGS]: ${AM_CPPFLAGS}
+    [AM_CFLAGS]: ${AM_CFLAGS}
+  [AM_CXXFLAGS]: ${AM_CXXFLAGS}
+   [AM_LDFLAGS]: ${AM_LDFLAGS}
+
+User flags (override Automake flags on conflict):
+     CPPFLAGS: ${CPPFLAGS}
+       CFLAGS: ${CFLAGS}
+     CXXFLAGS: ${CXXFLAGS}
+      LDFLAGS: ${LDFLAGS}])
diff --git a/contrib/expat/doc/Makefile.am b/contrib/expat/doc/Makefile.am
index e2f029837a41..16987e8dec40 100644
--- a/contrib/expat/doc/Makefile.am
+++ b/contrib/expat/doc/Makefile.am
@@ -6,7 +6,9 @@
 #                      \___/_/\_\ .__/ \__,_|\__|
 #                               |_| XML parser
 #
-# Copyright (c) 2017 Expat development team
+# Copyright (c) 2017-2021 Sebastian Pipping <sebastian@pipping.org>
+# Copyright (c) 2017      Stephen Groat <stephen@groat.us>
+# Copyright (c) 2017      Joe Orton <jorton@redhat.com>
 # Licensed under the MIT license:
 #
 # Permission is  hereby granted,  free of charge,  to any  person obtaining
@@ -52,7 +54,7 @@ clean-local-check:
 	$(RM) xmlwf.1
 
 EXTRA_DIST = \
-    expat.png \
+    ok.min.css \
     reference.html \
     style.css \
     valid-xhtml10.png \
diff --git a/contrib/expat/doc/Makefile.in b/contrib/expat/doc/Makefile.in
index e021e8c675fe..c48834052935 100644
--- a/contrib/expat/doc/Makefile.in
+++ b/contrib/expat/doc/Makefile.in
@@ -1,7 +1,7 @@
-# Makefile.in generated by automake 1.16.1 from Makefile.am.
+# Makefile.in generated by automake 1.16.5 from Makefile.am.
 # @configure_input@
 
-# Copyright (C) 1994-2018 Free Software Foundation, Inc.
+# Copyright (C) 1994-2021 Free Software Foundation, Inc.
 
 # This Makefile.in is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
@@ -22,7 +22,9 @@
 #                      \___/_/\_\ .__/ \__,_|\__|
 #                               |_| XML parser
 #
-# Copyright (c) 2017 Expat development team
+# Copyright (c) 2017-2021 Sebastian Pipping <sebastian@pipping.org>
+# Copyright (c) 2017      Stephen Groat <stephen@groat.us>
+# Copyright (c) 2017      Joe Orton <jorton@redhat.com>
 # Licensed under the MIT license:
 #
 # Permission is  hereby granted,  free of charge,  to any  person obtaining
@@ -193,7 +195,11 @@ am__DIST_COMMON = $(dist_man_MANS) $(srcdir)/Makefile.in
 DISTFILES = $(DIST_COMMON) $(DIST_SOURCES) $(TEXINFOS) $(EXTRA_DIST)
 ACLOCAL = @ACLOCAL@
 AMTAR = @AMTAR@
+AM_CFLAGS = @AM_CFLAGS@
+AM_CPPFLAGS = @AM_CPPFLAGS@
+AM_CXXFLAGS = @AM_CXXFLAGS@
 AM_DEFAULT_VERBOSITY = @AM_DEFAULT_VERBOSITY@
+AM_LDFLAGS = @AM_LDFLAGS@
 AR = @AR@
 AS = @AS@
 AUTOCONF = @AUTOCONF@
@@ -203,8 +209,9 @@ AWK = @AWK@
 CC = @CC@
 CCDEPMODE = @CCDEPMODE@
 CFLAGS = @CFLAGS@
-CPP = @CPP@
 CPPFLAGS = @CPPFLAGS@
+CSCOPE = @CSCOPE@
+CTAGS = @CTAGS@
 CXX = @CXX@
 CXXCPP = @CXXCPP@
 CXXDEPMODE = @CXXDEPMODE@
@@ -220,7 +227,15 @@ ECHO_C = @ECHO_C@
 ECHO_N = @ECHO_N@
 ECHO_T = @ECHO_T@
 EGREP = @EGREP@
+ETAGS = @ETAGS@
 EXEEXT = @EXEEXT@
+EXPAT_ATTR_INFO = @EXPAT_ATTR_INFO@
+EXPAT_CHAR_TYPE = @EXPAT_CHAR_TYPE@
+EXPAT_CONTEXT_BYTES = @EXPAT_CONTEXT_BYTES@
+EXPAT_DTD = @EXPAT_DTD@
+EXPAT_LARGE_SIZE = @EXPAT_LARGE_SIZE@
+EXPAT_MIN_SIZE = @EXPAT_MIN_SIZE@
+EXPAT_NS = @EXPAT_NS@
 FGREP = @FGREP@
 FILEMAP = @FILEMAP@
 GREP = @GREP@
@@ -233,6 +248,8 @@ LD = @LD@
 LDFLAGS = @LDFLAGS@
 LIBAGE = @LIBAGE@
 LIBCURRENT = @LIBCURRENT@
+LIBDIR_BASENAME = @LIBDIR_BASENAME@
+LIBM = @LIBM@
 LIBOBJS = @LIBOBJS@
 LIBREVISION = @LIBREVISION@
 LIBS = @LIBS@
@@ -262,6 +279,9 @@ RANLIB = @RANLIB@
 SED = @SED@
 SET_MAKE = @SET_MAKE@
 SHELL = @SHELL@
+SO_MAJOR = @SO_MAJOR@
+SO_MINOR = @SO_MINOR@
+SO_PATCH = @SO_PATCH@
 STRIP = @STRIP@
 VERSION = @VERSION@
 abs_builddir = @abs_builddir@
@@ -272,6 +292,7 @@ ac_ct_AR = @ac_ct_AR@
 ac_ct_CC = @ac_ct_CC@
 ac_ct_CXX = @ac_ct_CXX@
 ac_ct_DUMPBIN = @ac_ct_DUMPBIN@
+ac_cv_sizeof_void_p = @ac_cv_sizeof_void_p@
 am__include = @am__include@
 am__leading_dot = @am__leading_dot@
 am__quote = @am__quote@
@@ -309,6 +330,7 @@ pdfdir = @pdfdir@
 prefix = @prefix@
 program_transform_name = @program_transform_name@
 psdir = @psdir@
+runstatedir = @runstatedir@
 sbindir = @sbindir@
 sharedstatedir = @sharedstatedir@
 srcdir = @srcdir@
@@ -319,7 +341,7 @@ top_builddir = @top_builddir@
 top_srcdir = @top_srcdir@
 @WITH_DOCBOOK_TRUE@dist_man_MANS = xmlwf.1
 EXTRA_DIST = \
-    expat.png \
+    ok.min.css \
     reference.html \
     style.css \
     valid-xhtml10.png \
@@ -413,7 +435,6 @@ ctags CTAGS:
 cscope cscopelist:
 
 @WITH_DOCBOOK_TRUE@dist-hook:
-
 distdir: $(BUILT_SOURCES)
 	$(MAKE) $(AM_MAKEFLAGS) distdir-am
 
diff --git a/contrib/expat/doc/expat.png b/contrib/expat/doc/expat.png
deleted file mode 100644
index 3d88eac4a133..000000000000
--- a/contrib/expat/doc/expat.png
+++ /dev/null
diff --git a/contrib/expat/doc/ok.min.css b/contrib/expat/doc/ok.min.css
new file mode 100644
index 000000000000..8b5f86e7042c
--- /dev/null
+++ b/contrib/expat/doc/ok.min.css
@@ -0,0 +1,2 @@
+/*! OK.css v1.0.3 | MIT License | github.com/andrewh0/okcss */@import url("https://rsms.me/inter/inter.css");
+/*! normalize.css v8.0.1 | MIT License | github.com/necolas/normalize.css */html{line-height:1.15}body{margin:0}main{display:block}h1{font-size:2em;margin:.67em 0}hr{box-sizing:content-box;height:0;overflow:visible}pre{font-family:monospace,monospace;font-size:1em}a{background-color:transparent}abbr[title]{border-bottom:none;text-decoration:underline;-webkit-text-decoration:underline dotted;text-decoration:underline dotted}b,strong{font-weight:bolder}code,kbd,samp{font-family:monospace,monospace;font-size:1em}small{font-size:80%}sub,sup{font-size:75%;line-height:0;position:relative;vertical-align:baseline}sub{bottom:-.25em}sup{top:-.5em}img{border-style:none}button,input,optgroup,select,textarea{font-size:100%;line-height:1.15;margin:0}button,input{overflow:visible}button,select{text-transform:none}[type=button],[type=reset],[type=submit],button{-webkit-appearance:button}[type=button]::-moz-focus-inner,[type=reset]::-moz-focus-inner,[type=submit]::-moz-focus-inner,button::-moz-focus-inner{border-style:none;padding:0}[type=button]:-moz-focusring,[type=reset]:-moz-focusring,[type=submit]:-moz-focusring,button:-moz-focusring{outline:1px dotted ButtonText}fieldset{padding:.35em .75em .625em}legend{box-sizing:border-box;color:inherit;display:table;max-width:100%;padding:0;white-space:normal}progress{vertical-align:baseline}textarea{overflow:auto}[type=checkbox],[type=radio]{box-sizing:border-box;padding:0}[type=number]::-webkit-inner-spin-button,[type=number]::-webkit-outer-spin-button{height:auto}[type=search]{-webkit-appearance:textfield;outline-offset:-2px}[type=search]::-webkit-search-decoration{-webkit-appearance:none}::-webkit-file-upload-button{-webkit-appearance:button;font:inherit}details{display:block}summary{display:list-item}[hidden],template{display:none}:root{--ok-sans:"Inter",system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Oxygen,Ubuntu,Cantarell,"Open Sans","Helvetica Neue","Noto Sans",sans-serif,"Apple Color Emoji","Segoe UI Emoji","Segoe UI Symbol","Noto Color Emoji";--ok-mono:SFMono-Regular,Menlo,Monaco,Consolas,"Ubuntu Mono","Liberation Mono","Courier New",Courier,monospace;--ok-fw-0:400;--ok-fw-1:600;--ok-fw-2:700;--ok-fw-3:700;--ok-fs-0:2.5rem;--ok-fs-1:2rem;--ok-fs-2:1.5rem;--ok-fs-3:1.25rem;--ok-fs-4:1rem;--ok-fs-5:0.75rem;--ok-br:0.25rem;--ok-s-0:0;--ok-s-1:0.25rem;--ok-s-2:0.5rem;--ok-s-3:1rem;--ok-s-4:1.5rem;--ok-s-5:2rem;--ok-s-6:2.5rem;--ok-lh-body:1.5;--ok-lh-heading:1.25;--ok-t-hl:#ffcf30;--ok-accent-0:#3e67fa;--ok-accent-1:#4788ff;--ok-tc-accent:#3173de;--ok-tc-code:#c23a30;--ok-tc-0:#000;--ok-tc-1:#747474;--ok-tc-2:#848484;--ok-bg-0:#fff;--ok-bg-1:#f0f0f0;--ok-bg-2:#ccc;--ok-b-0:1px solid #cbcbcb;--ok-b-1:1px solid #848484;--ok-down-0:url("data:image/svg+xml;charset=utf-8,%3Csvg xmlns='http://www.w3.org/2000/svg' height='8' viewBox='0 0 12 8' width='24' fill='none'%3E%3Cpath d='M6 6l4-4h1v1-1L6 7 1 2h1l4 4z' fill='%23747474'/%3E%3C/svg%3E");--ok-down-1:url("data:image/svg+xml;charset=utf-8,%3Csvg xmlns='http://www.w3.org/2000/svg' height='8' viewBox='0 0 12 8' width='24' fill='none'%3E%3Cpath d='M6 6l4-4h1v1-1L6 7 1 2h1l4 4z' fill='%23848484'/%3E%3C/svg%3E")}@media (prefers-color-scheme:dark){:root{--ok-tc-accent:#5c9aff;--ok-tc-code:#ed5853;--ok-tc-0:#fff;--ok-tc-1:#ababab;--ok-tc-2:#929292;--ok-bg-0:#000;--ok-bg-1:#212121;--ok-bg-2:#3e3e3e;--ok-b-0:1px solid #747474;--ok-b-1:1px solid #929292;--ok-down-0:url("data:image/svg+xml;charset=utf-8,%3Csvg xmlns='http://www.w3.org/2000/svg' height='8' viewBox='0 0 12 8' width='24' fill='none'%3E%3Cpath d='M6 6l4-4h1v1-1L6 7 1 2h1l4 4z' fill='%23ababab'/%3E%3C/svg%3E");--ok-down-1:url("data:image/svg+xml;charset=utf-8,%3Csvg xmlns='http://www.w3.org/2000/svg' height='8' viewBox='0 0 12 8' width='24' fill='none'%3E%3Cpath d='M6 6l4-4h1v1-1L6 7 1 2h1l4 4z' fill='%23929292'/%3E%3C/svg%3E")}}*,:after,:before{box-sizing:border-box}*{margin:0;padding:0}html{font-family:var(--ok-sans);line-sizing:normal;line-height:var(--ok-lh-body);font-weight:var(--ok-fw-0);color:var(--ok-tc-0);background-color:var(--ok-bg-0);-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale;-webkit-text-size-adjust:100%;-moz-text-size-adjust:100%;-ms-text-size-adjust:100%;text-size-adjust:100%;text-rendering:optimizeLegibility}@supports (font-variation-settings:normal){html{font-family:Inter var,var(--ok-sans)}}button,input,optgroup,select,textarea{font-family:inherit;line-height:var(--ok-lh-body)}[role=button],button{cursor:pointer}audio,canvas,embed,iframe,img,input,object,select,svg,textarea,video{display:block}img,video{max-width:100%;height:auto}body{padding:var(--ok-s-3);max-width:80ch;margin:auto}h1{font-size:var(--ok-fs-0);margin:0}h2{font-size:var(--ok-fs-1)}h3{font-size:var(--ok-fs-2)}h4{font-size:var(--ok-fs-3)}h5{font-size:var(--ok-fs-4)}h6{font-size:var(--ok-fs-5);text-transform:uppercase;font-weight:var(--ok-fw-1)}h1,h2,h3,h4,h5,h6{line-height:var(--ok-lh-heading);font-weight:var(--ok-fw-3)}p{font-size:var(--ok-fs-4)}small{font-size:var(--ok-fs-5)}b,dt,strong{font-weight:var(--ok-fw-2)}address,article,aside,audio,blockquote,button,canvas,dd,details,dialog,div,dl,embed,fieldset,figcaption,figure,footer,form,h1,h2,h3,h4,h5,h6,header,hgroup,hr,iframe,img,input,main,nav,object,ol,p,pre,section,select,summary,svg,table,textarea,ul,video{margin-bottom:var(--ok-s-4)}address:last-child,article:last-child,aside:last-child,blockquote:last-child,dd:last-child,details:last-child,dialog:last-child,div:last-child,dl:last-child,dt:last-child,fieldset:last-child,figcaption:last-child,figure:last-child,footer:last-child,form:last-child,h1:last-child,h2:last-child,h3:last-child,h4:last-child,h5:last-child,h6:last-child,header:last-child,hgroup:last-child,hr:last-child,input[type=checkbox],input[type=radio],main:last-child,nav:last-child,ol:last-child,p:last-child,pre:last-child,section:last-child,table:last-child,ul:last-child{margin-bottom:0}fieldset{padding:var(--ok-s-3);border:var(--ok-b-0);border-radius:var(--ok-br)}legend{font-weight:var(--ok-fw-1);text-transform:uppercase;font-size:var(--ok-fs-5)}input,select{padding:var(--ok-s-2);background:var(--ok-bg-0);border:var(--ok-b-0);border-radius:var(--ok-br);color:var(--ok-tc-0);min-width:25ch}input:disabled,select:disabled,textarea:disabled{color:var(--ok-tc-2)}input::placeholder,textarea::placeholder{color:var(--ok-tc-2)}input::-webkit-input-placeholder,textarea::-webkit-input-placeholder{color:var(--ok-tc-2)}input::-moz-placeholder,textarea::-moz-placeholder{color:var(--ok-tc-2)}input:-ms-input-placeholder,textarea:-ms-input-placeholder{color:var(--ok-tc-2)}input::-ms-input-placeholder,textarea::-ms-input-placeholder{color:var(--ok-tc-2)}input::-webkit-clear-button,input::-webkit-inner-spin-button,input::-webkit-search-cancel-button,input::-webkit-search-results-button{display:none}input::-ms-clear,input::-ms-reveal{display:none}input:disabled,textarea:disabled{background-color:var(--ok-bg-1)}input[type=search]{-webkit-appearance:none;-moz-appearance:none;appearance:none}input[type=file]{max-width:300px}input[type=number]{-moz-appearance:textfield}input[type=checkbox],input[type=radio]{display:inline;min-width:auto}input[type=color]{height:2.5rem}input[type=date],input[type=datetime-local],input[type=month],input[type=time],input[type=week]{height:2.5rem;-webkit-appearance:none;-moz-appearance:none;appearance:none;position:relative}input[type=date]:before,input[type=datetime-local]:before,input[type=month]:before,input[type=time]:before,input[type=week]:before{position:absolute;right:0;top:0;background-image:var(--ok-down-0);background-repeat:no-repeat;background-position:right .2em top 50%;background-size:2em auto;width:2.5rem;height:calc(2.5rem - 2px);content:""}input[type=date]:disabled:before,input[type=datetime-local]:disabled:before,input[type=month]:disabled:before,input[type=time]:disabled:before,input[type=week]:disabled:before{background-image:var(--ok-down-1)}input::-webkit-calendar-picker-indicator{position:absolute;top:0;right:0;background-color:transparent;cursor:pointer;padding:0;width:2.5rem;height:calc(2.5rem - 2px);content:"";opacity:0}input[type=range]{overflow:visible;line-height:inherit;font-family:inherit;-webkit-appearance:none;-moz-appearance:none;appearance:none;margin:0;outline:none;cursor:pointer;padding:0;vertical-align:middle;border:none;min-height:2rem;background-color:transparent}input[type=range]::-webkit-slider-runnable-track{cursor:pointer;-webkit-appearance:none;border-radius:var(--ok-br);border:var(--ok-b-0);background-color:var(--ok-bg-1);background-image:linear-gradient(var(--ok-bg-1),var(--ok-bg-1));width:100%;height:.5rem;color:transparent;box-sizing:border-box;position:relative}input[type=range]::-moz-range-track{cursor:pointer;-moz-appearance:none;border-radius:var(--ok-br);border:var(--ok-b-0);background-color:var(--ok-bg-1);background-image:linear-gradient(var(--ok-bg-1),var(--ok-bg-1));width:100%;height:.5rem;color:transparent;box-sizing:border-box}input[type=range]::-ms-track{cursor:pointer;-ms-appearance:none;border-radius:var(--ok-br);border:var(--ok-b-0);background-color:var(--ok-bg-1);background-image:linear-gradient(var(--ok-bg-1),var(--ok-bg-1));width:100%;height:.5rem;color:transparent;box-sizing:border-box}input[type=range]::-ms-fill-lower{background:transparent}input[type=range]::-webkit-slider-thumb{cursor:pointer;-webkit-appearance:none;border-radius:50%;background-color:var(--ok-accent-0);width:1.5rem;height:1.5rem;margin-top:calc(-.5rem - 1px)}input[type=range]::-moz-range-thumb{cursor:pointer;-moz-appearance:none;border:none;border-radius:50%;background-color:var(--ok-accent-0);width:1.5rem;height:1.5rem}input[type=range]::-ms-thumb{cursor:pointer;-ms-appearance:none;border-radius:50%;background-color:var(--ok-accent-0);width:1.5rem;height:1.5rem;transform:translateY(.25rem)}input[type=range]:focus:not(:disabled)::-webkit-slider-thumb{background-color:var(--ok-accent-1)}input[type=range]:focus:not(:disabled)::-moz-range-thumb{background-color:var(--ok-accent-1)}input[type=range]:focus:not(:disabled)::-ms-thumb{background-color:var(--ok-accent-1)}input[type=range]:disabled{cursor:default}input[type=range]:disabled::-webkit-slider-runnable-track{cursor:default}input[type=range]:disabled::-moz-range-track{cursor:default}input[type=range]:disabled::-ms-track{cursor:default}input[type=range]:disabled::-webkit-slider-thumb{background-color:var(--ok-bg-2);cursor:default}input[type=range]:disabled::-moz-range-thumb{background-color:var(--ok-bg-2);cursor:default}input[type=range]:disabled::-ms-thumb{background-color:var(--ok-bg-2);cursor:default}select{-webkit-appearance:none;-moz-appearance:none;appearance:none;border:var(--ok-b-0);border-radius:var(--ok-br);background-color:var(--ok-bg-0);min-height:2.5rem;color:var(--ok-tc-0)}select:not([multiple]){background-image:var(--ok-down-0);background-repeat:no-repeat,repeat;background-position:right .2em top 50%;background-size:2em auto;padding-right:2.5em;height:2.5rem}select::-ms-expand{display:none}select:not([multiple]):disabled{background-image:var(--ok-down-1);background-color:var(--ok-bg-1);cursor:default}select[multiple]{border-radius:var(--ok-br)}select[multiple]:disabled{background-color:var(--ok-bg-1)}select[multiple] option{color:var(--ok-t-)}select[multiple]:disabled option{color:var(--ok-tc-2)}textarea{padding:var(--ok-s-2);resize:vertical;background:var(--ok-bg-0);border:var(--ok-b-0);border-radius:var(--ok-br);color:var(--ok-tc-0);min-height:calc(2.5rem - 2px);min-width:25ch}button,input[type=button],input[type=reset],input[type=submit]{display:inline-block;background-color:var(--ok-accent-0);border-radius:var(--ok-br);color:#fff;font-weight:var(--ok-fw-1);height:2.5rem;border:none;padding:var(--ok-s-2) 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tr{background-color:var(--ok-bg-1);font-size:var(--ok-fs-5);text-transform:uppercase;color:var(--ok-tc-0)}td,th{border:var(--ok-b-0) 0;text-align:left;padding:.5rem}td{white-space:normal;max-width:20ch}tr{border:var(--ok-b-0)}table caption{font-size:var(--ok-fs-4);font-weight:var(--ok-fw-3);padding:.5rem}code,samp{padding:.2em .4em;color:var(--ok-tc-code)}code,pre,samp{font-family:var(--ok-mono);line-height:var(--ok-lh-body);background-color:var(--ok-bg-1);border-radius:var(--ok-br);text-transform:none}pre{padding:var(--ok-s-3);white-space:pre;overflow-x:auto}pre,var{color:var(--ok-tc-0)}var{font-family:var(--ok-mono);font-style:normal}code pre,pre code{background:inherit;font-size:inherit;color:inherit;border:0;padding:0;margin:0}code pre{display:inline}kbd{background-color:var(--ok-bg-1);border:var(--ok-b-0);border-radius:var(--ok-br);border-bottom:2px solid 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\ No newline at end of file
diff --git a/contrib/expat/doc/reference.html b/contrib/expat/doc/reference.html
index 23e9a979707b..1629413e541e 100644
--- a/contrib/expat/doc/reference.html
+++ b/contrib/expat/doc/reference.html
@@ -3,26 +3,55 @@
                       "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
 <html>
 <head>
-<!-- Copyright 1999,2000 Clark Cooper <coopercc@netheaven.com>
-     All rights reserved.
-     This is free software. You may distribute or modify according to
-     the terms of the MIT/X License -->
+<!--
+                            __  __            _
+                         ___\ \/ /_ __   __ _| |_
+                        / _ \\  /| '_ \ / _` | __|
+                       |  __//  \| |_) | (_| | |_
+                        \___/_/\_\ .__/ \__,_|\__|
+                                 |_| XML parser
+
+   Copyright (c) 2000      Clark Cooper <coopercc@users.sourceforge.net>
+   Copyright (c) 2000-2004 Fred L. Drake, Jr. <fdrake@users.sourceforge.net>
+   Copyright (c) 2002-2012 Karl Waclawek <karl@waclawek.net>
+   Copyright (c) 2017-2022 Sebastian Pipping <sebastian@pipping.org>
+   Copyright (c) 2017      Jakub Wilk <jwilk@jwilk.net>
+   Copyright (c) 2021      Tomas Korbar <tkorbar@redhat.com>
+   Copyright (c) 2021      Nicolas Cavallari <nicolas.cavallari@green-communications.fr>
+   Licensed under the MIT license:
+
+   Permission is  hereby granted,  free of charge,  to any  person obtaining
+   a  copy  of  this  software   and  associated  documentation  files  (the
+   "Software"),  to  deal in  the  Software  without restriction,  including
+   without  limitation the  rights  to use,  copy,  modify, merge,  publish,
+   distribute, sublicense, and/or sell copies of the Software, and to permit
+   persons  to whom  the Software  is  furnished to  do so,  subject to  the
+   following conditions:
+
+   The above copyright  notice and this permission notice  shall be included
+   in all copies or substantial portions of the Software.
+
+   THE  SOFTWARE  IS  PROVIDED  "AS  IS",  WITHOUT  WARRANTY  OF  ANY  KIND,
+   EXPRESS  OR IMPLIED,  INCLUDING  BUT  NOT LIMITED  TO  THE WARRANTIES  OF
+   MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+   NO EVENT SHALL THE AUTHORS OR  COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+   DAMAGES OR  OTHER LIABILITY, WHETHER  IN AN  ACTION OF CONTRACT,  TORT OR
+   OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+   USE OR OTHER DEALINGS IN THE SOFTWARE.
+-->
   <title>Expat XML Parser</title>
   <meta name="author" content="Clark Cooper, coopercc@netheaven.com" />
   <meta http-equiv="Content-Style-Type" content="text/css" />
+  <link href="ok.min.css" rel="stylesheet" type="text/css" />
   <link href="style.css" rel="stylesheet" type="text/css" />
 </head>
 <body>
-  <table cellspacing="0" cellpadding="0" width="100%">
-    <tr>
-      <td class="corner"><img src="expat.png" alt="(Expat logo)" /></td>
-      <td class="banner"><h1>The Expat XML Parser</h1></td>
-    </tr>
-    <tr>
-      <td class="releaseno">Release 2.0.1</td>
-      <td></td>
-    </tr>
-  </table>
+  <div>
+    <h1>
+      The Expat XML Parser
+      <small>Release 2.4.3</small>
+    </h1>
+  </div>
 <div class="content">
 
 <p>Expat is a library, written in C, for parsing XML documents. It's
@@ -120,6 +149,13 @@ interface.</p>
       <li><a href="#XML_GetInputContext">XML_GetInputContext</a></li>
     </ul>
     </li>
+    <li>
+      <a href="#billion-laughs">Billion Laughs Attack Protection</a>
+      <ul>
+        <li><a href="#XML_SetBillionLaughsAttackProtectionMaximumAmplification">XML_SetBillionLaughsAttackProtectionMaximumAmplification</a></li>
+        <li><a href="#XML_SetBillionLaughsAttackProtectionActivationThreshold">XML_SetBillionLaughsAttackProtectionActivationThreshold</a></li>
+      </ul>
+    </li>
     <li><a href="#miscellaneous">Miscellaneous Functions</a>
     <ul>
       <li><a href="#XML_SetUserData">XML_SetUserData</a></li>
@@ -900,7 +936,8 @@ whether the parse can be resumed in the future.</p>
 
 <h3><a name="creation">Parser Creation</a></h3>
 
-<pre class="fcndec" id="XML_ParserCreate">
+<h4 id="XML_ParserCreate">XML_ParserCreate</h4>
+<pre class="fcndec">
 XML_Parser XMLCALL
 XML_ParserCreate(const XML_Char *encoding);
 </pre>
@@ -917,7 +954,8 @@ encoding declaration. There are four built-in encodings:
 Any other value will invoke a call to the UnknownEncodingHandler.
 </div>
 
-<pre class="fcndec" id="XML_ParserCreateNS">
+<h4 id="XML_ParserCreateNS">XML_ParserCreateNS</h4>
+<pre class="fcndec">
 XML_Parser XMLCALL
 XML_ParserCreateNS(const XML_Char *encoding,
                    XML_Char sep);
@@ -936,7 +974,8 @@ the local part will be concatenated without any separator - this is intended
 to support RDF processors. It is a programming error to use the null separator
 with <a href= "#XML_SetReturnNSTriplet">namespace triplets</a>.</div>
 
-<pre class="fcndec" id="XML_ParserCreate_MM">
+<h4 id="XML_ParserCreate_MM">XML_ParserCreate_MM</h4>
+<pre class="fcndec">
 XML_Parser XMLCALL
 XML_ParserCreate_MM(const XML_Char *encoding,
                     const XML_Memory_Handling_Suite *ms,
@@ -958,7 +997,8 @@ and the character pointed at by sep is used as the separator between
 the namespace URI and the local part of the name.</p>
 </div>
 
-<pre class="fcndec" id="XML_ExternalEntityParserCreate">
+<h4 id="XML_ExternalEntityParserCreate">XML_ExternalEntityParserCreate</h4>
+<pre class="fcndec">
 XML_Parser XMLCALL
 XML_ExternalEntityParserCreate(XML_Parser p,
                                const XML_Char *context,
@@ -974,7 +1014,8 @@ changing functions on this parser (unless you want it to act
 differently than the parent parser).
 </div>
 
-<pre class="fcndec" id="XML_ParserFree">
+<h4 id="XML_ParserFree">XML_ParserFree</h4>
+<pre class="fcndec">
 void XMLCALL
 XML_ParserFree(XML_Parser p);
 </pre>
@@ -983,7 +1024,8 @@ Free memory used by the parser. Your application is responsible for
 freeing any memory associated with <a href="#userdata">user data</a>.
 </div>
 
-<pre class="fcndec" id="XML_ParserReset">
+<h4 id="XML_ParserReset">XML_ParserReset</h4>
+<pre class="fcndec">
 XML_Bool XMLCALL
 XML_ParserReset(XML_Parser p,
                 const XML_Char *encoding);
@@ -1014,7 +1056,7 @@ if they apply to the parser created by
 <code><a href= "#XML_ExternalEntityParserCreate"
 >XML_ExternalEntityParserCreate</a></code>.</p>
 
-<p>Note: the <code>len</code> argument passed to these functions
+<p>Note: The <code>len</code> argument passed to these functions
 should be considerably less than the maximum value for an integer,
 as it could create an integer overflow situation if the added
 lengths of a buffer and the unprocessed portion of the previous buffer
@@ -1022,7 +1064,8 @@ exceed the maximum integer value. Input data at the end of a buffer
 will remain unprocessed if it is part of an XML token for which the
 end is not part of that buffer.</p>
 
-<pre class="fcndec" id="XML_Parse">
+<h4 id="XML_Parse">XML_Parse</h4>
+<pre class="fcndec">
 enum XML_Status XMLCALL
 XML_Parse(XML_Parser p,
           const char *s,
@@ -1049,7 +1092,8 @@ If a parse error occurred, it returns <code>XML_STATUS_ERROR</code>.
 Otherwise it returns <code>XML_STATUS_OK</code> value.
 </div>
 
-<pre class="fcndec" id="XML_ParseBuffer">
+<h4 id="XML_ParseBuffer">XML_ParseBuffer</h4>
+<pre class="fcndec">
 enum XML_Status XMLCALL
 XML_ParseBuffer(XML_Parser p,
                 int len,
@@ -1063,7 +1107,8 @@ buffer from Expat with the <code><a href= "#XML_GetBuffer"
 copying of the input.
 </div>
 
-<pre class="fcndec" id="XML_GetBuffer">
+<h4 id="XML_GetBuffer">XML_GetBuffer</h4>
+<pre class="fcndec">
 void * XMLCALL
 XML_GetBuffer(XML_Parser p,
               int len);
@@ -1071,7 +1116,8 @@ XML_GetBuffer(XML_Parser p,
 <div class="fcndef">
 Obtain a buffer of size <code>len</code> to read a piece of the document
 into. A NULL value is returned if Expat can't allocate enough memory for
-this buffer. This has to be called prior to every call to
+this buffer. A NULL value may also be returned if <code>len</code> is zero.
+This has to be called prior to every call to
 <code><a href= "#XML_ParseBuffer" >XML_ParseBuffer</a></code>. A
 typical use would look like this:
 
@@ -1098,7 +1144,8 @@ for (;;) {
 </pre>
 </div>
 
-<pre class="fcndec" id="XML_StopParser">
+<h4 id="XML_StopParser">XML_StopParser</h4>
+<pre class="fcndec">
 enum XML_Status XMLCALL
 XML_StopParser(XML_Parser p,
                XML_Bool resumable);
@@ -1111,7 +1158,7 @@ XML_StopParser(XML_Parser p,
 call-back handler, except when aborting (when <code>resumable</code>
 is <code>XML_FALSE</code>) an already suspended parser.  Some
 call-backs may still follow because they would otherwise get
-lost, including
+lost, including</p>
 <ul>
   <li> the end element handler for empty elements when stopped in the
        start element handler,</li>
@@ -1120,7 +1167,7 @@ lost, including
   <li> the character data handler when stopped in the character data handler
        while making multiple call-backs on a contiguous chunk of characters,</li>
 </ul>
-and possibly others.</p>
+<p>and possibly others.</p>
 
 <p>This can be called from most handlers, including DTD related
 call-backs, except when parsing an external parameter entity and
@@ -1166,7 +1213,8 @@ implementation of that handler to call <code><a href=
 <p>New in Expat 1.95.8.</p>
 </div>
 
-<pre class="fcndec" id="XML_ResumeParser">
+<h4 id="XML_ResumeParser">XML_ResumeParser</h4>
+<pre class="fcndec">
 enum XML_Status XMLCALL
 XML_ResumeParser(XML_Parser p);
 </pre>
@@ -1191,7 +1239,8 @@ appropriate moment.</p>
 <p>New in Expat 1.95.8.</p>
 </div>
 
-<pre class="fcndec" id="XML_GetParsingStatus">
+<h4 id="XML_GetParsingStatus">XML_GetParsingStatus</h4>
+<pre class="fcndec">
 void XMLCALL
 XML_GetParsingStatus(XML_Parser p,
                      XML_ParsingStatus *status);
@@ -1240,7 +1289,8 @@ Note that you'll receive them in this form independent of the original
 encoding of the document.</p>
 
 <div class="handler">
-<pre class="setter" id="XML_SetStartElementHandler">
+<h4 id="XML_SetStartElementHandler">XML_SetStartElementHandler</h4>
+<pre class="setter">
 void XMLCALL
 XML_SetStartElementHandler(XML_Parser p,
                            XML_StartElementHandler start);
@@ -1261,7 +1311,8 @@ by a null pointer.</p>
 </div>
 
 <div class="handler">
-<pre class="setter" id="XML_SetEndElementHandler">
+<h4 id="XML_SetEndElementHandler">XML_SetEndElementHandler</h4>
+<pre class="setter">
 void XMLCALL
 XML_SetEndElementHandler(XML_Parser p,
                          XML_EndElementHandler);
@@ -1276,7 +1327,8 @@ generates a call to both start and end handlers.</p>
 </div>
 
 <div class="handler">
-<pre class="setter" id="XML_SetElementHandler">
+<h4 id="XML_SetElementHandler">XML_SetElementHandler</h4>
+<pre class="setter">
 void XMLCALL
 XML_SetElementHandler(XML_Parser p,
                       XML_StartElementHandler start,
@@ -1286,7 +1338,8 @@ XML_SetElementHandler(XML_Parser p,
 </div>
 
 <div class="handler">
-<pre class="setter" id="XML_SetCharacterDataHandler">
+<h4 id="XML_SetCharacterDataHandler">XML_SetCharacterDataHandler</h4>
+<pre class="setter">
 void XMLCALL
 XML_SetCharacterDataHandler(XML_Parser p,
                             XML_CharacterDataHandler charhndl)
@@ -1298,7 +1351,7 @@ typedef void
                                     int len);
 </pre>
 <p>Set a text handler. The string your handler receives
-is <em>NOT nul-terminated</em>. You have to use the length argument
+is <em>NOT null-terminated</em>. You have to use the length argument
 to deal with the end of the string. A single block of contiguous text
 free of markup may still result in a sequence of calls to this handler.
 In other words, if you're searching for a pattern in the text, it may
@@ -1309,7 +1362,8 @@ will continue calling back until the end of the block is reached.</p>
 </div>
 
 <div class="handler">
-<pre class="setter" id="XML_SetProcessingInstructionHandler">
+<h4 id="XML_SetProcessingInstructionHandler">XML_SetProcessingInstructionHandler</h4>
+<pre class="setter">
 void XMLCALL
 XML_SetProcessingInstructionHandler(XML_Parser p,
                                     XML_ProcessingInstructionHandler proc)
@@ -1327,7 +1381,8 @@ it after skipping all whitespace after the initial word.</p>
 </div>
 
 <div class="handler">
-<pre class="setter" id="XML_SetCommentHandler">
+<h4 id="XML_SetCommentHandler">XML_SetCommentHandler</h4>
+<pre class="setter">
 void XMLCALL
 XML_SetCommentHandler(XML_Parser p,
                       XML_CommentHandler cmnt)
@@ -1342,7 +1397,8 @@ delimiters.</p>
 </div>
 
 <div class="handler">
-<pre class="setter" id="XML_SetStartCdataSectionHandler">
+<h4 id="XML_SetStartCdataSectionHandler">XML_SetStartCdataSectionHandler</h4>
+<pre class="setter">
 void XMLCALL
 XML_SetStartCdataSectionHandler(XML_Parser p,
                                 XML_StartCdataSectionHandler start);
@@ -1355,7 +1411,8 @@ typedef void
 </div>
 
 <div class="handler">
-<pre class="setter" id="XML_SetEndCdataSectionHandler">
+<h4 id="XML_SetEndCdataSectionHandler">XML_SetEndCdataSectionHandler</h4>
+<pre class="setter">
 void XMLCALL
 XML_SetEndCdataSectionHandler(XML_Parser p,
                               XML_EndCdataSectionHandler end);
@@ -1368,7 +1425,8 @@ typedef void
 </div>
 
 <div class="handler">
-<pre class="setter" id="XML_SetCdataSectionHandler">
+<h4 id="XML_SetCdataSectionHandler">XML_SetCdataSectionHandler</h4>
+<pre class="setter">
 void XMLCALL
 XML_SetCdataSectionHandler(XML_Parser p,
                            XML_StartCdataSectionHandler start,
@@ -1378,7 +1436,8 @@ XML_SetCdataSectionHandler(XML_Parser p,
 </div>
 
 <div class="handler">
-<pre class="setter" id="XML_SetDefaultHandler">
+<h4 id="XML_SetDefaultHandler">XML_SetDefaultHandler</h4>
+<pre class="setter">
 void XMLCALL
 XML_SetDefaultHandler(XML_Parser p,
                       XML_DefaultHandler hndl)
@@ -1409,7 +1468,8 @@ href="#XML_DefaultCurrent">XML_DefaultCurrent</a></code>.</p>
 </div>
 
 <div class="handler">
-<pre class="setter" id="XML_SetDefaultHandlerExpand">
+<h4 id="XML_SetDefaultHandlerExpand">XML_SetDefaultHandlerExpand</h4>
+<pre class="setter">
 void XMLCALL
 XML_SetDefaultHandlerExpand(XML_Parser p,
                             XML_DefaultHandler hndl)
@@ -1429,7 +1489,8 @@ href="#XML_DefaultCurrent">XML_DefaultCurrent</a></code>.</p>
 </div>
 
 <div class="handler">
-<pre class="setter" id="XML_SetExternalEntityRefHandler">
+<h4 id="XML_SetExternalEntityRefHandler">XML_SetExternalEntityRefHandler</h4>
+<pre class="setter">
 void XMLCALL
 XML_SetExternalEntityRefHandler(XML_Parser p,
                                 XML_ExternalEntityRefHandler hndl)
@@ -1482,7 +1543,8 @@ parser, the body of the external entity can be recursively parsed.</p>
 information into global or static variables.</p>
 </div>
 
-<pre class="fcndec" id="XML_SetExternalEntityRefHandlerArg">
+<h4 id="XML_SetExternalEntityRefHandlerArg">XML_SetExternalEntityRefHandlerArg</h4>
+<pre class="fcndec">
 void XMLCALL
 XML_SetExternalEntityRefHandlerArg(XML_Parser p,
                                    void *arg)
@@ -1508,7 +1570,8 @@ properly.</p>
 </div>
 
 <div class="handler">
-<pre class="setter" id="XML_SetSkippedEntityHandler">
+<h4 id="XML_SetSkippedEntityHandler">XML_SetSkippedEntityHandler</h4>
+<pre class="setter">
 void XMLCALL
 XML_SetSkippedEntityHandler(XML_Parser p,
                             XML_SkippedEntityHandler handler)
@@ -1528,14 +1591,15 @@ typedef void
 	   has been called.</li>
 </ol>
 <p>The <code>is_parameter_entity</code> argument will be non-zero for
-a parameter entity and zero for a general entity.</p> <p>Note: skipped
+a parameter entity and zero for a general entity.</p> <p>Note: Skipped
 parameter entities in declarations and skipped general entities in
 attribute values cannot be reported, because the event would be out of
 sync with the reporting of the declarations or attribute values</p>
 </div>
 
 <div class="handler">
-<pre class="setter" id="XML_SetUnknownEncodingHandler">
+<h4 id="XML_SetUnknownEncodingHandler">XML_SetUnknownEncodingHandler</h4>
+<pre class="setter">
 void XMLCALL
 XML_SetUnknownEncodingHandler(XML_Parser p,
                               XML_UnknownEncodingHandler enchandler,
@@ -1576,7 +1640,7 @@ call to the function pointed at by convert. This function may return -1
 if the sequence itself is invalid. The convert pointer may be null if
 there are only single byte codes. The data parameter passed to the convert
 function is the data pointer from <code>XML_Encoding</code>. The
-string s is <em>NOT</em> nul-terminated and points at the sequence of
+string s is <em>NOT</em> null-terminated and points at the sequence of
 bytes to be converted.</p>
 
 <p>The function pointed at by <code>release</code> is called by the
@@ -1584,7 +1648,8 @@ parser when it is finished with the encoding. It may be NULL.</p>
 </div>
 
 <div class="handler">
-<pre class="setter" id="XML_SetStartNamespaceDeclHandler">
+<h4 id="XML_SetStartNamespaceDeclHandler">XML_SetStartNamespaceDeclHandler</h4>
+<pre class="setter">
 void XMLCALL
 XML_SetStartNamespaceDeclHandler(XML_Parser p,
 			         XML_StartNamespaceDeclHandler start);
@@ -1602,7 +1667,8 @@ in that start tag.</p>
 </div>
 
 <div class="handler">
-<pre class="setter" id="XML_SetEndNamespaceDeclHandler">
+<h4 id="XML_SetEndNamespaceDeclHandler">XML_SetEndNamespaceDeclHandler</h4>
+<pre class="setter">
 void XMLCALL
 XML_SetEndNamespaceDeclHandler(XML_Parser p,
 			       XML_EndNamespaceDeclHandler end);
@@ -1619,7 +1685,8 @@ namespace was declared.</p>
 </div>
 
 <div class="handler">
-<pre class="setter" id="XML_SetNamespaceDeclHandler">
+<h4 id="XML_SetNamespaceDeclHandler">XML_SetNamespaceDeclHandler</h4>
+<pre class="setter">
 void XMLCALL
 XML_SetNamespaceDeclHandler(XML_Parser p,
                             XML_StartNamespaceDeclHandler start,
@@ -1629,7 +1696,8 @@ XML_SetNamespaceDeclHandler(XML_Parser p,
 </div>
 
 <div class="handler">
-<pre class="setter" id="XML_SetXmlDeclHandler">
+<h4 id="XML_SetXmlDeclHandler">XML_SetXmlDeclHandler</h4>
+<pre class="setter">
 void XMLCALL
 XML_SetXmlDeclHandler(XML_Parser p,
 		      XML_XmlDeclHandler xmldecl);
@@ -1652,7 +1720,8 @@ that it was given as yes.</p>
 </div>
 
 <div class="handler">
-<pre class="setter" id="XML_SetStartDoctypeDeclHandler">
+<h4 id="XML_SetStartDoctypeDeclHandler">XML_SetStartDoctypeDeclHandler</h4>
+<pre class="setter">
 void XMLCALL
 XML_SetStartDoctypeDeclHandler(XML_Parser p,
 			       XML_StartDoctypeDeclHandler start);
@@ -1672,7 +1741,8 @@ will be non-zero if the DOCTYPE declaration has an internal subset.</p>
 </div>
 
 <div class="handler">
-<pre class="setter" id="XML_SetEndDoctypeDeclHandler">
+<h4 id="XML_SetEndDoctypeDeclHandler">XML_SetEndDoctypeDeclHandler</h4>
+<pre class="setter">
 void XMLCALL
 XML_SetEndDoctypeDeclHandler(XML_Parser p,
 			     XML_EndDoctypeDeclHandler end);
@@ -1686,7 +1756,8 @@ after parsing any external subset.</p>
 </div>
 
 <div class="handler">
-<pre class="setter" id="XML_SetDoctypeDeclHandler">
+<h4 id="XML_SetDoctypeDeclHandler">XML_SetDoctypeDeclHandler</h4>
+<pre class="setter">
 void XMLCALL
 XML_SetDoctypeDeclHandler(XML_Parser p,
 			  XML_StartDoctypeDeclHandler start,
@@ -1696,7 +1767,8 @@ XML_SetDoctypeDeclHandler(XML_Parser p,
 </div>
 
 <div class="handler">
-<pre class="setter" id="XML_SetElementDeclHandler">
+<h4 id="XML_SetElementDeclHandler">XML_SetElementDeclHandler</h4>
+<pre class="setter">
 void XMLCALL
 XML_SetElementDeclHandler(XML_Parser p,
 			  XML_ElementDeclHandler eldecl);
@@ -1768,7 +1840,8 @@ or sequence and <code>children</code> points to the nodes.</p>
 </div>
 
 <div class="handler">
-<pre class="setter" id="XML_SetAttlistDeclHandler">
+<h4 id="XML_SetAttlistDeclHandler">XML_SetAttlistDeclHandler</h4>
+<pre class="setter">
 void XMLCALL
 XML_SetAttlistDeclHandler(XML_Parser p,
                           XML_AttlistDeclHandler attdecl);
@@ -1801,7 +1874,8 @@ in the <code>dflt</code> parameter.</p>
 </div>
 
 <div class="handler">
-<pre class="setter" id="XML_SetEntityDeclHandler">
+<h4 id="XML_SetEntityDeclHandler">XML_SetEntityDeclHandler</h4>
+<pre class="setter">
 void XMLCALL
 XML_SetEntityDeclHandler(XML_Parser p,
 			 XML_EntityDeclHandler handler);
@@ -1835,7 +1909,8 @@ declarations.</p>
 </div>
 
 <div class="handler">
-<pre class="setter" id="XML_SetUnparsedEntityDeclHandler">
+<h4 id="XML_SetUnparsedEntityDeclHandler">XML_SetUnparsedEntityDeclHandler</h4>
+<pre class="setter">
 void XMLCALL
 XML_SetUnparsedEntityDeclHandler(XML_Parser p,
                                  XML_UnparsedEntityDeclHandler h)
@@ -1861,7 +1936,8 @@ compatibility.  Use instead <a href= "#XML_SetEntityDeclHandler"
 </div>
 
 <div class="handler">
-<pre class="setter" id="XML_SetNotationDeclHandler">
+<h4 id="XML_SetNotationDeclHandler">XML_SetNotationDeclHandler</h4>
+<pre class="setter">
 void XMLCALL
 XML_SetNotationDeclHandler(XML_Parser p,
                            XML_NotationDeclHandler h)
@@ -1878,7 +1954,8 @@ typedef void
 </div>
 
 <div class="handler">
-<pre class="setter" id="XML_SetNotStandaloneHandler">
+<h4 id="XML_SetNotStandaloneHandler">XML_SetNotStandaloneHandler</h4>
+<pre class="setter">
 void XMLCALL
 XML_SetNotStandaloneHandler(XML_Parser p,
                             XML_NotStandaloneHandler h)
@@ -1904,7 +1981,7 @@ of errors. The position reported is the byte position (in the original
 document or entity encoding) of the first of the sequence of
 characters that generated the current event (or the error that caused
 the parse functions to return <code>XML_STATUS_ERROR</code>.)  The
-exceptions are callbacks trigged by declarations in the document
+exceptions are callbacks triggered by declarations in the document
 prologue, in which case they exact position reported is somewhere in the
 relevant markup, but not necessarily as meaningful as for other
 events.</p>
@@ -1913,7 +1990,8 @@ events.</p>
 DTD.  In other words, they usually return bogus information when
 called from within a DTD declaration handler.</p>
 
-<pre class="fcndec" id="XML_GetErrorCode">
+<h4 id="XML_GetErrorCode">XML_GetErrorCode</h4>
+<pre class="fcndec">
 enum XML_Error XMLCALL
 XML_GetErrorCode(XML_Parser p);
 </pre>
@@ -1921,7 +1999,8 @@ XML_GetErrorCode(XML_Parser p);
 Return what type of error has occurred.
 </div>
 
-<pre class="fcndec" id="XML_ErrorString">
+<h4 id="XML_ErrorString">XML_ErrorString</h4>
+<pre class="fcndec">
 const XML_LChar * XMLCALL
 XML_ErrorString(enum XML_Error code);
 </pre>
@@ -1931,7 +2010,8 @@ The code should be one of the enums that can be returned from
 <code><a href= "#XML_GetErrorCode" >XML_GetErrorCode</a></code>.
 </div>
 
-<pre class="fcndec" id="XML_GetCurrentByteIndex">
+<h4 id="XML_GetCurrentByteIndex">XML_GetCurrentByteIndex</h4>
+<pre class="fcndec">
 XML_Index XMLCALL
 XML_GetCurrentByteIndex(XML_Parser p);
 </pre>
@@ -1942,7 +2022,8 @@ the values returned by <code><a href= "#XML_GetCurrentLineNumber"
 "#XML_GetCurrentColumnNumber" >XML_GetCurrentColumnNumber</a></code>.
 </div>
 
-<pre class="fcndec" id="XML_GetCurrentLineNumber">
+<h4 id="XML_GetCurrentLineNumber">XML_GetCurrentLineNumber</h4>
+<pre class="fcndec">
 XML_Size XMLCALL
 XML_GetCurrentLineNumber(XML_Parser p);
 </pre>
@@ -1951,7 +2032,8 @@ Return the line number of the position.  The first line is reported as
 <code>1</code>.
 </div>
 
-<pre class="fcndec" id="XML_GetCurrentColumnNumber">
+<h4 id="XML_GetCurrentColumnNumber">XML_GetCurrentColumnNumber</h4>
+<pre class="fcndec">
 XML_Size XMLCALL
 XML_GetCurrentColumnNumber(XML_Parser p);
 </pre>
@@ -1960,7 +2042,8 @@ Return the offset, from the beginning of the current line, of
 the position.
 </div>
 
-<pre class="fcndec" id="XML_GetCurrentByteCount">
+<h4 id="XML_GetCurrentByteCount">XML_GetCurrentByteCount</h4>
+<pre class="fcndec">
 int XMLCALL
 XML_GetCurrentByteCount(XML_Parser p);
 </pre>
@@ -1972,7 +2055,8 @@ be used to distinguish empty-element tags from empty elements using
 separate start and end tags).
 </div>
 
-<pre class="fcndec" id="XML_GetInputContext">
+<h4 id="XML_GetInputContext">XML_GetInputContext</h4>
+<pre class="fcndec">
 const char * XMLCALL
 XML_GetInputContext(XML_Parser p,
                     int *offset,
@@ -1998,12 +2082,105 @@ parse position may be before the beginning of the buffer.</p>
 return NULL.</p>
 </div>
 
+<h3><a name="billion-laughs">Billion Laughs Attack Protection</a></h3>
+
+<p>The functions in this section configure the built-in
+  protection against various forms of
+  <a href="https://en.wikipedia.org/wiki/Billion_laughs_attack">billion laughs attacks</a>.</p>
+
+<h4 id="XML_SetBillionLaughsAttackProtectionMaximumAmplification">XML_SetBillionLaughsAttackProtectionMaximumAmplification</h4>
+<pre class="fcndec">
+/* Added in Expat 2.4.0. */
+XML_Bool XMLCALL
+XML_SetBillionLaughsAttackProtectionMaximumAmplification(XML_Parser p,
+                                                         float maximumAmplificationFactor);
+</pre>
+<div class="fcndef">
+  <p>
+    Sets the maximum tolerated amplification factor
+    for protection against
+    <a href="https://en.wikipedia.org/wiki/Billion_laughs_attack">billion laughs attacks</a>
+    (default: <code>100.0</code>)
+    of parser <code>p</code> to <code>maximumAmplificationFactor</code>, and
+    returns <code>XML_TRUE</code> upon success and <code>XML_FALSE</code> upon error.
+  </p>
+
+  The amplification factor is calculated as ..
+  <pre>
+    amplification := (direct + indirect) / direct
+  </pre>
+  .. while parsing, whereas
+  <code>direct</code> is the number of bytes read from the primary document in parsing and
+  <code>indirect</code> is the number of bytes added by expanding entities and reading of external DTD files, combined.
+
+  <p>For a call to <code>XML_SetBillionLaughsAttackProtectionMaximumAmplification</code> to succeed:</p>
+  <ul>
+    <li>parser <code>p</code> must be a non-<code>NULL</code> root parser (without any parent parsers) and</li>
+    <li><code>maximumAmplificationFactor</code> must be non-<code>NaN</code> and greater than or equal to <code>1.0</code>.</li>
+  </ul>
+
+  <p>
+    <strong>Note:</strong>
+    If you ever need to increase this value for non-attack payload,
+    please <a href="https://github.com/libexpat/libexpat/issues">file a bug report</a>.
+  </p>
+
+  <p>
+    <strong>Note:</strong>
+    Peak amplifications
+    of factor 15,000 for the entire payload and
+    of factor 30,000 in the middle of parsing
+    have been observed with small benign files in practice.
+
+    So if you do reduce the maximum allowed amplification,
+    please make sure that the activation threshold is still big enough
+    to not end up with undesired false positives (i.e. benign files being rejected).
+  </p>
+</div>
+
+<h4 id="XML_SetBillionLaughsAttackProtectionActivationThreshold">XML_SetBillionLaughsAttackProtectionActivationThreshold</h4>
+<pre class="fcndec">
+/* Added in Expat 2.4.0. */
+XML_Bool XMLCALL
+XML_SetBillionLaughsAttackProtectionActivationThreshold(XML_Parser p,
+                                                        unsigned long long activationThresholdBytes);
+</pre>
+<div class="fcndef">
+  <p>
+    Sets number of output bytes (including amplification from entity expansion and reading DTD files)
+    needed to activate protection against
+    <a href="https://en.wikipedia.org/wiki/Billion_laughs_attack">billion laughs attacks</a>
+    (default: <code>8 MiB</code>)
+    of parser <code>p</code> to <code>activationThresholdBytes</code>, and
+    returns <code>XML_TRUE</code> upon success and <code>XML_FALSE</code> upon error.
+  </p>
+
+  <p>For a call to <code>XML_SetBillionLaughsAttackProtectionActivationThreshold</code> to succeed:</p>
+  <ul>
+    <li>parser <code>p</code> must be a non-<code>NULL</code> root parser (without any parent parsers).</li>
+  </ul>
+
+  <p>
+    <strong>Note:</strong>
+    If you ever need to increase this value for non-attack payload,
+    please <a href="https://github.com/libexpat/libexpat/issues">file a bug report</a>.
+  </p>
+
+  <p>
+    <strong>Note:</strong>
+    Activation thresholds below 4 MiB are known to break support for
+    <a href="https://en.wikipedia.org/wiki/Darwin_Information_Typing_Architecture">DITA</a> 1.3 payload
+    and are hence not recommended.
+  </p>
+</div>
+
 <h3><a name="miscellaneous">Miscellaneous functions</a></h3>
 
 <p>The functions in this section either obtain state information from
 the parser or can be used to dynamically set parser options.</p>
 
-<pre class="fcndec" id="XML_SetUserData">
+<h4 id="XML_SetUserData">XML_SetUserData</h4>
+<pre class="fcndec">
 void XMLCALL
 XML_SetUserData(XML_Parser p,
                 void *userData);
@@ -2018,7 +2195,8 @@ the memory associated with it, then you've probably just leaked
 memory.
 </div>
 
-<pre class="fcndec" id="XML_GetUserData">
+<h4 id="XML_GetUserData">XML_GetUserData</h4>
+<pre class="fcndec">
 void * XMLCALL
 XML_GetUserData(XML_Parser p);
 </pre>
@@ -2027,7 +2205,8 @@ This returns the user data pointer that gets passed to handlers.
 It is actually implemented as a macro.
 </div>
 
-<pre class="fcndec" id="XML_UseParserAsHandlerArg">
+<h4 id="XML_UseParserAsHandlerArg">XML_UseParserAsHandlerArg</h4>
+<pre class="fcndec">
 void XMLCALL
 XML_UseParserAsHandlerArg(XML_Parser p);
 </pre>
@@ -2038,7 +2217,8 @@ using the <code><a href= "#XML_GetUserData"
 >XML_GetUserData</a></code> function.
 </div>
 
-<pre class="fcndec" id="XML_SetBase">
+<h4 id="XML_SetBase">XML_SetBase</h4>
+<pre class="fcndec">
 enum XML_Status XMLCALL
 XML_SetBase(XML_Parser p,
             const XML_Char *base);
@@ -2050,7 +2230,8 @@ there's no memory to store base, otherwise it's
 <code>XML_STATUS_OK</code>.
 </div>
 
-<pre class="fcndec" id="XML_GetBase">
+<h4 id="XML_GetBase">XML_GetBase</h4>
+<pre class="fcndec">
 const XML_Char * XMLCALL
 XML_GetBase(XML_Parser p);
 </pre>
@@ -2058,7 +2239,8 @@ XML_GetBase(XML_Parser p);
 Return the base for resolving relative URIs.
 </div>
 
-<pre class="fcndec" id="XML_GetSpecifiedAttributeCount">
+<h4 id="XML_GetSpecifiedAttributeCount">XML_GetSpecifiedAttributeCount</h4>
+<pre class="fcndec">
 int XMLCALL
 XML_GetSpecifiedAttributeCount(XML_Parser p);
 </pre>
@@ -2074,7 +2256,8 @@ call to a start handler. If called inside a start handler, then that
 means the current call.
 </div>
 
-<pre class="fcndec" id="XML_GetIdAttributeIndex">
+<h4 id="XML_GetIdAttributeIndex">XML_GetIdAttributeIndex</h4>
+<pre class="fcndec">
 int XMLCALL
 XML_GetIdAttributeIndex(XML_Parser p);
 </pre>
@@ -2086,7 +2269,8 @@ attribute. If called inside a start handler, then that means the
 current call.
 </div>
 
-<pre class="fcndec" id="XML_GetAttributeInfo">
+<h4 id="XML_GetAttributeInfo">XML_GetAttributeInfo</h4>
+<pre class="fcndec">
 const XML_AttrInfo * XMLCALL
 XML_GetAttributeInfo(XML_Parser parser);
 </pre>
@@ -2107,7 +2291,8 @@ as 1; thus the number of entries in the array is
 <code>XML_GetSpecifiedAttributeCount(parser) / 2</code>.
 </div>
 
-<pre class="fcndec" id="XML_SetEncoding">
+<h4 id="XML_SetEncoding">XML_SetEncoding</h4>
+<pre class="fcndec">
 enum XML_Status XMLCALL
 XML_SetEncoding(XML_Parser p,
                 const XML_Char *encoding);
@@ -2122,7 +2307,8 @@ Returns <code>XML_STATUS_OK</code> on success or
 <code>XML_STATUS_ERROR</code> on error.
 </div>
 
-<pre class="fcndec" id="XML_SetParamEntityParsing">
+<h4 id="XML_SetParamEntityParsing">XML_SetParamEntityParsing</h4>
+<pre class="fcndec">
 int XMLCALL
 XML_SetParamEntityParsing(XML_Parser p,
                           enum XML_ParamEntityParsing code);
@@ -2142,7 +2328,8 @@ The choices for <code>code</code> are:
 no effect and will always return 0.
 </div>
 
-<pre class="fcndec" id="XML_SetHashSalt">
+<h4 id="XML_SetHashSalt">XML_SetHashSalt</h4>
+<pre class="fcndec">
 int XMLCALL
 XML_SetHashSalt(XML_Parser p,
                 unsigned long hash_salt);
@@ -2153,15 +2340,16 @@ Helps in preventing DoS attacks based on predicting hash
 function behavior. In order to have an effect this must be called
 before parsing has started. Returns 1 if successful, 0 when called
 after <code>XML_Parse</code> or <code>XML_ParseBuffer</code>.
-<p><b>Note:</b>This call is optional, as the parser will auto-generate 
+<p><b>Note:</b> This call is optional, as the parser will auto-generate
 a new random salt value if no value has been set at the start of parsing.</p>
-<p><b>Note:</b>One should not call <code>XML_SetHashSalt</code> with a
+<p><b>Note:</b> One should not call <code>XML_SetHashSalt</code> with a
 hash salt value of 0, as this value is used as sentinel value to indicate
 that <code>XML_SetHashSalt</code> has <b>not</b> been called. Consequently
 such a call will have no effect, even if it returns 1.</p>
 </div>
 
-<pre class="fcndec" id="XML_UseForeignDTD">
+<h4 id="XML_UseForeignDTD">XML_UseForeignDTD</h4>
+<pre class="fcndec">
 enum XML_Error XMLCALL
 XML_UseForeignDTD(XML_Parser parser, XML_Bool useDTD);
 </pre>
@@ -2198,7 +2386,8 @@ the document had a DTD with an external subset. This holds true even if
 the external entity reference handler returns without action.</p>
 </div>
 
-<pre class="fcndec" id="XML_SetReturnNSTriplet">
+<h4 id="XML_SetReturnNSTriplet">XML_SetReturnNSTriplet</h4>
+<pre class="fcndec">
 void XMLCALL
 XML_SetReturnNSTriplet(XML_Parser parser,
                        int        do_nst);
@@ -2220,7 +2409,8 @@ default manner, URI then local_name separated by the namespace
 separator.</p>
 </div>
 
-<pre class="fcndec" id="XML_DefaultCurrent">
+<h4 id="XML_DefaultCurrent">XML_DefaultCurrent</h4>
+<pre class="fcndec">
 void XMLCALL
 XML_DefaultCurrent(XML_Parser parser);
 </pre>
@@ -2234,7 +2424,8 @@ href="#XML_SetDefaultHandler" >XML_SetDefaultHandler</a></code> or
 not a default handler.
 </div>
 
-<pre class="fcndec" id="XML_ExpatVersion">
+<h4 id="XML_ExpatVersion">XML_ExpatVersion</h4>
+<pre class="fcndec">
 XML_LChar * XMLCALL
 XML_ExpatVersion();
 </pre>
@@ -2242,7 +2433,8 @@ XML_ExpatVersion();
 Return the library version as a string (e.g. <code>"expat_1.95.1"</code>).
 </div>
 
-<pre class="fcndec" id="XML_ExpatVersionInfo">
+<h4 id="XML_ExpatVersionInfo">XML_ExpatVersionInfo</h4>
+<pre class="fcndec">
 struct XML_Expat_Version XMLCALL
 XML_ExpatVersionInfo();
 </pre>
@@ -2266,7 +2458,8 @@ Testing these constants is currently the best way to determine if
 particular parts of the Expat API are available.
 </div>
 
-<pre class="fcndec" id="XML_GetFeatureList">
+<h4 id="XML_GetFeatureList">XML_GetFeatureList</h4>
+<pre class="fcndec">
 const XML_Feature * XMLCALL
 XML_GetFeatureList();
 </pre>
@@ -2327,7 +2520,8 @@ time, the following features have been defined to have values:</p>
 </dl>
 </div>
 
-<pre class="fcndec" id="XML_FreeContentModel">
+<h4 id="XML_FreeContentModel">XML_FreeContentModel</h4>
+<pre class="fcndec">
 void XMLCALL
 XML_FreeContentModel(XML_Parser parser, XML_Content *model);
 </pre>
@@ -2346,7 +2540,8 @@ applications.  This can be essential when using dynamically loaded
 libraries which use different C standard libraries (this can happen on
 Windows, at least).</p>
 
-<pre class="fcndec" id="XML_MemMalloc">
+<h4 id="XML_MemMalloc">XML_MemMalloc</h4>
+<pre class="fcndec">
 void * XMLCALL
 XML_MemMalloc(XML_Parser parser, size_t size);
 </pre>
@@ -2358,7 +2553,8 @@ way must be freed using <code><a href="#XML_MemFree"
 >XML_MemFree</a></code>.
 </div>
 
-<pre class="fcndec" id="XML_MemRealloc">
+<h4 id="XML_MemRealloc">XML_MemRealloc</h4>
+<pre class="fcndec">
 void * XMLCALL
 XML_MemRealloc(XML_Parser parser, void *ptr, size_t size);
 </pre>
@@ -2377,7 +2573,8 @@ original block.  Memory allocated in this way must be freed using
 >XML_MemFree</a></code>.
 </div>
 
-<pre class="fcndec" id="XML_MemFree">
+<h4 id="XML_MemFree">XML_MemFree</h4>
+<pre class="fcndec">
 void XMLCALL
 XML_MemFree(XML_Parser parser, void *ptr);
 </pre>
@@ -2388,9 +2585,12 @@ have been allocated by <code><a href="#XML_MemMalloc"
 </div>
 
 <hr />
-<p><a href="http://validator.w3.org/check/referer"><img
-        src="valid-xhtml10.png" alt="Valid XHTML 1.0!"
-        height="31" width="88" class="noborder" /></a></p>
+
+  <div class="footer">
+    Found a bug in the documentation?
+    <a href="https://github.com/libexpat/libexpat/issues">Please file a bug report.</a>
+  </div>
+
 </div>
 </body>
 </html>
diff --git a/contrib/expat/doc/style.css b/contrib/expat/doc/style.css
index 69df30bcecb2..1b8cd10dffa4 100644
--- a/contrib/expat/doc/style.css
+++ b/contrib/expat/doc/style.css
@@ -1,101 +1,47 @@
+/*
+                            __  __            _
+                         ___\ \/ /_ __   __ _| |_
+                        / _ \\  /| '_ \ / _` | __|
+                       |  __//  \| |_) | (_| | |_
+                        \___/_/\_\ .__/ \__,_|\__|
+                                 |_| XML parser
+
+   Copyright (c) 2000      Clark Cooper <coopercc@users.sourceforge.net>
+   Copyright (c) 2000-2004 Fred L. Drake, Jr. <fdrake@users.sourceforge.net>
+   Copyright (c) 2021      Sebastian Pipping <sebastian@pipping.org>
+   Licensed under the MIT license:
+
+   Permission is  hereby granted,  free of charge,  to any  person obtaining
+   a  copy  of  this  software   and  associated  documentation  files  (the
+   "Software"),  to  deal in  the  Software  without restriction,  including
+   without  limitation the  rights  to use,  copy,  modify, merge,  publish,
+   distribute, sublicense, and/or sell copies of the Software, and to permit
+   persons  to whom  the Software  is  furnished to  do so,  subject to  the
+   following conditions:
+
+   The above copyright  notice and this permission notice  shall be included
+   in all copies or substantial portions of the Software.
+
+   THE  SOFTWARE  IS  PROVIDED  "AS  IS",  WITHOUT  WARRANTY  OF  ANY  KIND,
+   EXPRESS  OR IMPLIED,  INCLUDING  BUT  NOT LIMITED  TO  THE WARRANTIES  OF
+   MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+   NO EVENT SHALL THE AUTHORS OR  COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+   DAMAGES OR  OTHER LIABILITY, WHETHER  IN AN  ACTION OF CONTRACT,  TORT OR
+   OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+   USE OR OTHER DEALINGS IN THE SOFTWARE.
+*/
+
+/* Stop not using half the screen */
 body {
-  background-color: white;
-  border: 0px;
-  margin: 0px;
-  padding: 0px;
-}
-
-.corner {
-  width: 200px;
-  height: 80px;
-  text-align: center;
-}
-
-.banner {
-  background-color: rgb(110,139,61);
-  color: rgb(255,236,176);
-  padding-left: 2em;
-}
-
-.banner h1 {
-  font-size: 200%;
-}
-
-.content {
-  padding: 0em 2em 1em 2em;
-}
-
-.releaseno {
-  background-color: rgb(110,139,61);
-  color: rgb(255,236,176);
-  padding-bottom: 0.3em;
-  padding-top: 0.5em;
-  text-align: center;
-  font-weight: bold;
-}
-
-.noborder {
-  border-width: 0px;
-}
-
-.eg {
-  padding-left: 1em;
-  padding-top: .5em;
-  padding-bottom: .5em;
-  border: solid thin;
-  margin: 1em 0;
-  background-color: tan;
-  margin-left: 2em;
-  margin-right: 10%;
-}
-
-.pseudocode {
-  padding-left: 1em;
-  padding-top: .5em;
-  padding-bottom: .5em;
-  border: solid thin;
-  margin: 1em 0;
-  background-color: rgb(250,220,180);
-  margin-left: 2em;
-  margin-right: 10%;
-}
-
-.handler {
-  width: 100%;
-  border-top-width: thin;  
-  margin-bottom: 1em;
-}
-
-.handler p {
-  margin-left: 2em;
-}
-
-.setter {
-  font-weight: bold;
-}
-
-.signature {
-  color: navy;
-}
-
-.fcndec {
-  width: 100%;
-  border-top-width: thin;
-  font-weight: bold;
-}
-
-.fcndef {
-  margin-left: 2em;
-  margin-bottom: 2em;
-}
-
-dd {
-  margin-bottom: 2em;
+  max-width: none; /* was: 80ch */
 }
 
 .cpp-symbols dt {
   font-family: monospace;
 }
-.cpp-symbols dd {
-  margin-bottom: 1em;
+
+/* Resemble style of <footer> which is not part of xhtml1-strict */
+.footer {
+  font-size: var(--ok-fs-5);
+  color: var(--ok-tc-1);
 }
diff --git a/contrib/expat/doc/xmlwf.1 b/contrib/expat/doc/xmlwf.1
index 57230689ef23..f76353173f62 100644
--- a/contrib/expat/doc/xmlwf.1
+++ b/contrib/expat/doc/xmlwf.1
@@ -5,7 +5,7 @@
 \\$2 \(la\\$1\(ra\\$3
 ..
 .if \n(.g .mso www.tmac
-.TH XMLWF 1 "March 11, 2016" "" ""
+.TH XMLWF 1 "January 16, 2022" "" ""
 .SH NAME
 xmlwf \- Determines if an XML document is well-formed
 .SH SYNOPSIS
@@ -15,7 +15,27 @@ xmlwf \- Determines if an XML document is well-formed
 \fBxmlwf\fR \kx
 .if (\nx>(\n(.l/2)) .nr x (\n(.l/5)
 'in \n(.iu+\nxu
-[\fB-s\fR] [\fB-n\fR] [\fB-p\fR] [\fB-x\fR] [\fB-e \fIencoding\fB\fR] [\fB-w\fR] [\fB-d \fIoutput-dir\fB\fR] [\fB-c\fR] [\fB-m\fR] [\fB-r\fR] [\fB-t\fR] [\fB-N\fR] [\fB-v\fR] [file ...]
+[\fIOPTIONS\fR] [\fIFILE\fR ...]
+'in \n(.iu-\nxu
+.ad b
+'hy
+'nh
+.fi
+.ad l
+\fBxmlwf\fR \kx
+.if (\nx>(\n(.l/2)) .nr x (\n(.l/5)
+'in \n(.iu+\nxu
+\fB-h\fR 
+'in \n(.iu-\nxu
+.ad b
+'hy
+'nh
+.fi
+.ad l
+\fBxmlwf\fR \kx
+.if (\nx>(\n(.l/2)) .nr x (\n(.l/5)
+'in \n(.iu+\nxu
+\fB-v\fR 
 'in \n(.iu-\nxu
 .ad b
 'hy
@@ -34,7 +54,7 @@ following rules:
 \(bu
 The file begins with an XML declaration. For instance,
 \*(T<<?xml version="1.0" standalone="yes"?>\*(T>.
-\fINOTE:\fR
+\fINOTE\fR:
 \fBxmlwf\fR does not currently
 check for a valid XML declaration.
 .TP 0.2i
@@ -62,10 +82,42 @@ it does not check the DTD. However, it does support
 external entities (see the \*(T<\fB\-x\fR\*(T> option).
 .SH OPTIONS
 When an option includes an argument, you may specify the argument either
-separately ("\*(T<\fB\-d\fR\*(T> output") or concatenated with the
-option ("\*(T<\fB\-d\fR\*(T>output"). \fBxmlwf\fR
+separately ("\*(T<\fB\-d\fR\*(T> \fIoutput\fR") or concatenated with the
+option ("\*(T<\fB\-d\fR\*(T>\fIoutput\fR"). \fBxmlwf\fR
 supports both.
 .TP 
+\*(T<\fB\-a\fR\*(T> \fIfactor\fR
+Sets the maximum tolerated amplification factor
+for protection against billion laughs attacks (default: 100.0).
+The amplification factor is calculated as ..
+
+.nf
+
+            amplification := (direct + indirect) / direct
+          
+.fi
+
+\&.. while parsing, whereas
+<direct> is the number of bytes read
+from the primary document in parsing and
+<indirect> is the number of bytes
+added by expanding entities and reading of external DTD files,
+combined.
+
+\fINOTE\fR:
+If you ever need to increase this value for non-attack payload,
+please file a bug report.
+.TP 
+\*(T<\fB\-b\fR\*(T> \fIbytes\fR
+Sets the number of output bytes (including amplification)
+needed to activate protection against billion laughs attacks
+(default: 8 MiB).
+This can be thought of as an "activation threshold".
+
+\fINOTE\fR:
+If you ever need to increase this value for non-attack payload,
+please file a bug report.
+.TP 
 \*(T<\fB\-c\fR\*(T>
 If the input file is well-formed and \fBxmlwf\fR
 doesn't encounter any errors, the input file is simply copied to
@@ -73,7 +125,7 @@ the output directory unchanged.
 This implies no namespaces (turns off \*(T<\fB\-n\fR\*(T>) and
 requires \*(T<\fB\-d\fR\*(T> to specify an output directory.
 .TP 
-\*(T<\fB\-d output\-dir\fR\*(T>
+\*(T<\fB\-d\fR\*(T> \fIoutput-dir\fR
 Specifies a directory to contain transformed
 representations of the input files.
 By default, \*(T<\fB\-d\fR\*(T> outputs a canonical representation
@@ -96,7 +148,7 @@ is treated equivalently to data.
 More on canonical XML can be found at
 http://www.jclark.com/xml/canonxml.html .
 .TP 
-\*(T<\fB\-e encoding\fR\*(T>
+\*(T<\fB\-e\fR\*(T> \fIencoding\fR
 Specifies the character encoding for the document, overriding
 any document encoding declaration. \fBxmlwf\fR
 supports four built-in encodings:
@@ -106,6 +158,15 @@ supports four built-in encodings:
 \*(T<ISO\-8859\-1\*(T>.
 Also see the \*(T<\fB\-w\fR\*(T> option.
 .TP 
+\*(T<\fB\-k\fR\*(T>
+When processing multiple files, \fBxmlwf\fR
+by default halts after the the first file with an error.
+This tells \fBxmlwf\fR to report the error
+but to keep processing.
+This can be useful, for example, when testing a filter that converts
+many files to XML and you want to quickly find out which conversions
+failed.
+.TP 
 \*(T<\fB\-m\fR\*(T>
 Outputs some strange sort of XML file that completely
 describes the input file, including character positions.
@@ -121,7 +182,7 @@ This matches the example output used by the formal XML test cases.
 Requires \*(T<\fB\-d\fR\*(T> to specify an output file.
 .TP 
 \*(T<\fB\-p\fR\*(T>
-Tells xmlwf to process external DTDs and parameter
+Tells \fBxmlwf\fR to process external DTDs and parameter
 entities.
 
 Normally \fBxmlwf\fR never parses parameter
@@ -165,7 +226,7 @@ then exits.
 Enables support for Windows code pages.
 Normally, \fBxmlwf\fR will throw an error if it
 runs across an encoding that it is not equipped to handle itself. With
-\*(T<\fB\-w\fR\*(T>, xmlwf will try to use a Windows code
+\*(T<\fB\-w\fR\*(T>, \fBxmlwf\fR will try to use a Windows code
 page. See also \*(T<\fB\-e\fR\*(T>.
 .TP 
 \*(T<\fB\-x\fR\*(T>
@@ -210,18 +271,33 @@ will run \fBxmlwf\fR on the file
 Older versions of \fBxmlwf\fR do not support
 reading from standard input.
 .SH OUTPUT
-If an input file is not well-formed,
-\fBxmlwf\fR prints a single line describing
-the problem to standard output. If a file is well formed,
-\fBxmlwf\fR outputs nothing.
-Note that the result code is \fInot\fR set.
-.SH BUGS
-\fBxmlwf\fR returns a 0 - noerr result,
-even if the file is not well-formed. There is no good way for
-a program to use \fBxmlwf\fR to quickly
-check a file -- it must parse \fBxmlwf\fR's
-standard output.
+\fBxmlwf\fR outputs nothing for files which are problem-free.
+If any input file is not well-formed, or if the output for any
+input file cannot be opened, \fBxmlwf\fR prints a single
+line describing the problem to standard output.
 .PP
+If the \*(T<\fB\-k\fR\*(T> option is not provided, \fBxmlwf\fR
+halts upon encountering a well-formedness or output-file error. 
+If \*(T<\fB\-k\fR\*(T> is provided, \fBxmlwf\fR continues
+processing the remaining input files, describing problems found with any of them.
+.SH "EXIT STATUS"
+For option \*(T<\fB\-v\fR\*(T> or \*(T<\fB\-h\fR\*(T>, \fBxmlwf\fR always exits with status code 0. For other cases, the following exit status codes are returned:
+.TP 
+\*(T<\fB0\fR\*(T>
+The input files are well-formed and the output (if requested) was written successfully.
+.TP 
+\*(T<\fB1\fR\*(T>
+An internal error occurred.
+.TP 
+\*(T<\fB2\fR\*(T>
+One or more input files were not well-formed or could not be parsed.
+.TP 
+\*(T<\fB3\fR\*(T>
+If using the \*(T<\fB\-d\fR\*(T> option, an error occurred opening an output file.
+.TP 
+\*(T<\fB4\fR\*(T>
+There was a command-line argument error in how \fBxmlwf\fR was invoked.
+.SH BUGS
 The errors should go to standard error, not standard output.
 .PP
 There should be a way to get \*(T<\fB\-d\fR\*(T> to send its
@@ -232,24 +308,16 @@ I have no idea why anyone would want to use the
 \*(T<\fB\-d\fR\*(T>, \*(T<\fB\-c\fR\*(T>, and
 \*(T<\fB\-m\fR\*(T> options. If someone could explain it to
 me, I'd like to add this information to this manpage.
-.SH ALTERNATIVES
-Here are some XML validators on the web:
-
-.nf
-
-http://www.hcrc.ed.ac.uk/~richard/xml\-check.html
-http://www.stg.brown.edu/service/xmlvalid/
-http://www.scripting.com/frontier5/xml/code/xmlValidator.html
-http://www.xml.com/pub/a/tools/ruwf/check.html
-.fi
 .SH "SEE ALSO"
 .nf
 
-The Expat home page:        http://www.libexpat.org/
-The W3 XML specification:   http://www.w3.org/TR/REC\-xml
+The Expat home page:                            https://libexpat.github.io/
+The W3 XML 1.0 specification (fourth edition):  https://www.w3.org/TR/2006/REC\-xml\-20060816/
+Billion laughs attack:                          https://en.wikipedia.org/wiki/Billion_laughs_attack
 .fi
 .SH AUTHOR
-This manual page was written by Scott Bronson <\*(T<bronson@rinspin.com\*(T>> for
+This manual page was originally written by Scott Bronson <\*(T<bronson@rinspin.com\*(T>>
+in December 2001 for
 the Debian GNU/Linux system (but may be used by others). Permission is
 granted to copy, distribute and/or modify this document under
 the terms of the GNU Free Documentation
diff --git a/contrib/expat/doc/xmlwf.xml b/contrib/expat/doc/xmlwf.xml
index 5e2a4ae94ab3..804fc5620eda 100644
--- a/contrib/expat/doc/xmlwf.xml
+++ b/contrib/expat/doc/xmlwf.xml
@@ -1,11 +1,28 @@
-<!DOCTYPE refentry [
-  <!-- Fill in your name for FIRSTNAME and SURNAME. -->
+<!--
+                            __  __            _
+                         ___\ \/ /_ __   __ _| |_
+                        / _ \\  /| '_ \ / _` | __|
+                       |  __//  \| |_) | (_| | |_
+                        \___/_/\_\ .__/ \__,_|\__|
+                                 |_| XML parser
+
+   Copyright (c) 2001      Scott Bronson <bronson@rinspin.com>
+   Copyright (c) 2002-2003 Fred L. Drake, Jr. <fdrake@users.sourceforge.net>
+   Copyright (c) 2009      Karl Waclawek <karl@waclawek.net>
+   Copyright (c) 2016-2022 Sebastian Pipping <sebastian@pipping.org>
+   Copyright (c) 2016      Ardo van Rangelrooij <ardo@debian.org>
+   Copyright (c) 2017      Rhodri James <rhodri@wildebeest.org.uk>
+   Copyright (c) 2020      Joe Orton <jorton@redhat.com>
+   Copyright (c) 2021      Tim Bray <tbray@textuality.com>
+   Unlike most of Expat,
+   this file is copyrighted under the GNU Free Documentation License 1.1.
+-->
+<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
+          "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd" [
   <!ENTITY dhfirstname "<firstname>Scott</firstname>">
   <!ENTITY dhsurname   "<surname>Bronson</surname>">
   <!-- Please adjust the date whenever revising the manpage. -->
-  <!ENTITY dhdate      "<date>March 11, 2016</date>">
-  <!-- SECTION should be 1-8, maybe w/ subsection other parameters are
-       allowed: see man(7), man(1). -->
+  <!ENTITY dhdate      "<date>January 16, 2022</date>">
   <!ENTITY dhsection   "<manvolnum>1</manvolnum>">
   <!ENTITY dhemail     "<email>bronson@rinspin.com</email>">
   <!ENTITY dhusername  "Scott Bronson">
@@ -44,25 +61,16 @@
   <refsynopsisdiv>
     <cmdsynopsis>
       <command>&dhpackage;</command>
-	  <arg><option>-s</option></arg>
-	  <arg><option>-n</option></arg>
-	  <arg><option>-p</option></arg>
-	  <arg><option>-x</option></arg>
-
-	  <arg><option>-e <replaceable>encoding</replaceable></option></arg>
-	  <arg><option>-w</option></arg>
-
-	  <arg><option>-d <replaceable>output-dir</replaceable></option></arg>
-	  <arg><option>-c</option></arg>
-	  <arg><option>-m</option></arg>
-
-	  <arg><option>-r</option></arg>
-	  <arg><option>-t</option></arg>
-          <arg><option>-N</option></arg>
-
-	  <arg><option>-v</option></arg>
-
-	  <arg>file ...</arg>
+      <arg><replaceable>OPTIONS</replaceable></arg>
+      <arg><replaceable>FILE</replaceable> ...</arg>
+    </cmdsynopsis>
+    <cmdsynopsis>
+      <command>&dhpackage;</command>
+      <arg choice="plain"><option>-h</option></arg>
+    </cmdsynopsis>
+    <cmdsynopsis>
+      <command>&dhpackage;</command>
+      <arg choice="plain"><option>-v</option></arg>
     </cmdsynopsis>
   </refsynopsisdiv>
  
@@ -95,7 +103,7 @@
       <listitem><para>
 	    The file begins with an XML declaration.  For instance,
 		<literal>&lt;?xml version="1.0" standalone="yes"?&gt;</literal>.
-		<emphasis>NOTE:</emphasis>
+		<emphasis>NOTE</emphasis>:
 		<command>&dhpackage;</command> does not currently
 		check for a valid XML declaration.
       </para></listitem>
@@ -132,14 +140,58 @@
 
 <para>
 When an option includes an argument, you may specify the argument either
-separately ("<option>-d</option> output") or concatenated with the
-option ("<option>-d</option>output").  <command>&dhpackage;</command>
+separately ("<option>-d</option> <replaceable>output</replaceable>") or concatenated with the
+option ("<option>-d</option><replaceable>output</replaceable>").  <command>&dhpackage;</command>
 supports both.
 </para>
 
     <variablelist>
 
       <varlistentry>
+        <term><option>-a</option> <replaceable>factor</replaceable></term>
+        <listitem>
+          <para>
+            Sets the maximum tolerated amplification factor
+            for protection against billion laughs attacks (default: 100.0).
+            The amplification factor is calculated as ..
+          </para>
+          <literallayout>
+            amplification := (direct + indirect) / direct
+          </literallayout>
+          <para>
+            .. while parsing, whereas
+            &lt;direct&gt; is the number of bytes read
+              from the primary document in parsing and
+            &lt;indirect&gt; is the number of bytes
+              added by expanding entities and reading of external DTD files,
+              combined.
+          </para>
+          <para>
+            <emphasis>NOTE</emphasis>:
+            If you ever need to increase this value for non-attack payload,
+            please file a bug report.
+          </para>
+        </listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><option>-b</option> <replaceable>bytes</replaceable></term>
+        <listitem>
+          <para>
+            Sets the number of output bytes (including amplification)
+            needed to activate protection against billion laughs attacks
+            (default: 8 MiB).
+            This can be thought of as an &quot;activation threshold&quot;.
+          </para>
+          <para>
+            <emphasis>NOTE</emphasis>:
+            If you ever need to increase this value for non-attack payload,
+            please file a bug report.
+          </para>
+        </listitem>
+      </varlistentry>
+
+      <varlistentry>
         <term><option>-c</option></term>
         <listitem>
 		<para>
@@ -153,7 +205,7 @@ supports both.
       </varlistentry>
 
       <varlistentry>
-        <term><option>-d output-dir</option></term>
+        <term><option>-d</option> <replaceable>output-dir</replaceable></term>
         <listitem>
 		<para>
   Specifies a directory to contain transformed
@@ -184,7 +236,7 @@ supports both.
       </varlistentry>
 
       <varlistentry>
-        <term><option>-e encoding</option></term>
+        <term><option>-e</option> <replaceable>encoding</replaceable></term>
         <listitem>
 		<para>
    Specifies the character encoding for the document, overriding
@@ -200,6 +252,21 @@ supports both.
       </varlistentry>
 
       <varlistentry>
+        <term><option>-k</option></term>
+        <listitem>
+          <para>
+            When processing multiple files, <command>&dhpackage;</command>
+            by default halts after the the first file with an error.
+            This tells <command>&dhpackage;</command> to report the error
+            but to keep processing.
+            This can be useful, for example, when testing a filter that converts
+            many files to XML and you want to quickly find out which conversions
+            failed.
+          </para>
+        </listitem>
+      </varlistentry>
+
+      <varlistentry>
         <term><option>-m</option></term>
         <listitem>
 		<para>
@@ -235,7 +302,7 @@ supports both.
         <term><option>-p</option></term>
         <listitem>
 		<para>
-    Tells xmlwf to process external DTDs and parameter
+    Tells <command>&dhpackage;</command> to process external DTDs and parameter
     entities.
 	 </para>
 	 <para>
@@ -292,7 +359,7 @@ supports both.
 	   </para>
         </listitem>
       </varlistentry>
-
+      
       <varlistentry>
         <term><option>-v</option></term>
         <listitem>
@@ -311,7 +378,7 @@ supports both.
   Enables support for Windows code pages.
   Normally, <command>&dhpackage;</command> will throw an error if it
   runs across an encoding that it is not equipped to handle itself.  With
-  <option>-w</option>, &dhpackage; will try to use a Windows code
+  <option>-w</option>, <command>&dhpackage;</command> will try to use a Windows code
   page.  See also <option>-e</option>.
 	   </para>
         </listitem>
@@ -379,24 +446,56 @@ supports both.
   <refsect1>
   <title>OUTPUT</title>
     <para>
-	If an input file is not well-formed,
-	<command>&dhpackage;</command> prints a single line describing
-	the problem to standard output.  If a file is well formed,
-	<command>&dhpackage;</command> outputs nothing.
-	Note that the result code is <emphasis>not</emphasis> set.
+	<command>&dhpackage;</command> outputs nothing for files which are problem-free.
+        If any input file is not well-formed, or if the output for any
+	input file cannot be opened, <command>&dhpackage;</command> prints a single
+	line describing	the problem to standard output.
+    </para>
+    <para>
+        If the <option>-k</option> option is not provided, <command>&dhpackage;</command>
+	halts upon encountering a well-formedness or output-file error. 
+	If <option>-k</option> is provided, <command>&dhpackage;</command> continues
+	processing the remaining input files, describing problems found with any of them.
+    </para>
+  </refsect1>
+
+  <refsect1>
+  <title>EXIT STATUS</title>
+    <para>For option <option>-v</option> or <option>-h</option>, <command>&dhpackage;</command> always exits with status code 0.  For other cases, the following exit status codes are returned:
+    <variablelist>
+      <varlistentry>
+        <term><option>0</option></term>
+        <listitem><para>The input files are well-formed and the output (if requested) was written successfully.</para>
+        </listitem>
+      </varlistentry>
+      <varlistentry>
+        <term><option>1</option></term>
+        <listitem><para>An internal error occurred.</para>
+        </listitem>
+      </varlistentry>
+      <varlistentry>
+        <term><option>2</option></term>
+        <listitem><para>One or more input files were not well-formed or could not be parsed.</para>
+        </listitem>
+      </varlistentry>
+      <varlistentry>
+        <term><option>3</option></term>
+        <listitem><para>If using the <option>-d</option> option, an error occurred opening an output file.</para>
+        </listitem>
+      </varlistentry>
+      <varlistentry>
+        <term><option>4</option></term>
+        <listitem><para>There was a command-line argument error in how <command>&dhpackage;</command> was invoked.</para>
+        </listitem>
+      </varlistentry>
+    </variablelist>
 	</para>
   </refsect1>
+
   
   <refsect1>
     <title>BUGS</title>
 	<para>
-	<command>&dhpackage;</command> returns a 0 - noerr result,
-	even if the file is not well-formed.  There is no good way for
-	a program to use <command>&dhpackage;</command> to quickly
-	check a file -- it must parse <command>&dhpackage;</command>'s
-	standard output.
-	</para>
-	<para>
 	The errors should go to standard error, not standard output.
 	</para>
 	<para>
@@ -413,27 +512,13 @@ supports both.
   </refsect1>
 
   <refsect1>
-    <title>ALTERNATIVES</title>
-	<para>
-	  Here are some XML validators on the web:
-
-<literallayout>
-http://www.hcrc.ed.ac.uk/~richard/xml-check.html
-http://www.stg.brown.edu/service/xmlvalid/
-http://www.scripting.com/frontier5/xml/code/xmlValidator.html
-http://www.xml.com/pub/a/tools/ruwf/check.html
-</literallayout>
-
-		 </para>
-  </refsect1>
-
-  <refsect1>
     <title>SEE ALSO</title>
 	<para>
 
 <literallayout>
-The Expat home page:        http://www.libexpat.org/
-The W3 XML specification:   http://www.w3.org/TR/REC-xml
+The Expat home page:                            https://libexpat.github.io/
+The W3 XML 1.0 specification (fourth edition):  https://www.w3.org/TR/2006/REC-xml-20060816/
+Billion laughs attack:                          https://en.wikipedia.org/wiki/Billion_laughs_attack
 </literallayout>
 
 	</para>
@@ -442,7 +527,8 @@ The W3 XML specification:   http://www.w3.org/TR/REC-xml
   <refsect1>
     <title>AUTHOR</title>
     <para>
-	  This manual page was written by &dhusername; &dhemail; for
+      This manual page was originally written by &dhusername; &dhemail;
+      in December 2001 for
       the &debian; system (but may be used by others).  Permission is
       granted to copy, distribute and/or modify this document under
       the terms of the <acronym>GNU</acronym> Free Documentation
diff --git a/contrib/expat/examples/Makefile.am b/contrib/expat/examples/Makefile.am
index 99edf21227c9..d386b59297cd 100644
--- a/contrib/expat/examples/Makefile.am
+++ b/contrib/expat/examples/Makefile.am
@@ -6,7 +6,8 @@
 #                      \___/_/\_\ .__/ \__,_|\__|
 #                               |_| XML parser
 #
-# Copyright (c) 2017 Expat development team
+# Copyright (c) 2017 Sebastian Pipping <sebastian@pipping.org>
+# Copyright (c) 2020 Jeffrey Walton <noloader@gmail.com>
 # Licensed under the MIT license:
 #
 # Permission is  hereby granted,  free of charge,  to any  person obtaining
@@ -28,7 +29,7 @@
 # OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 # USE OR OTHER DEALINGS IN THE SOFTWARE.
 
-AM_CPPFLAGS = -I$(srcdir)/../lib
+AM_CPPFLAGS = @AM_CPPFLAGS@ -I$(srcdir)/../lib
 
 noinst_PROGRAMS = elements outline
 
diff --git a/contrib/expat/examples/Makefile.in b/contrib/expat/examples/Makefile.in
index 391c71ee93e2..d476e53526bd 100644
--- a/contrib/expat/examples/Makefile.in
+++ b/contrib/expat/examples/Makefile.in
@@ -1,7 +1,7 @@
-# Makefile.in generated by automake 1.16.1 from Makefile.am.
+# Makefile.in generated by automake 1.16.5 from Makefile.am.
 # @configure_input@
 
-# Copyright (C) 1994-2018 Free Software Foundation, Inc.
+# Copyright (C) 1994-2021 Free Software Foundation, Inc.
 
 # This Makefile.in is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
@@ -22,7 +22,8 @@
 #                      \___/_/\_\ .__/ \__,_|\__|
 #                               |_| XML parser
 #
-# Copyright (c) 2017 Expat development team
+# Copyright (c) 2017 Sebastian Pipping <sebastian@pipping.org>
+# Copyright (c) 2020 Jeffrey Walton <noloader@gmail.com>
 # Licensed under the MIT license:
 #
 # Permission is  hereby granted,  free of charge,  to any  person obtaining
@@ -210,14 +211,16 @@ am__define_uniq_tagged_files = \
   unique=`for i in $$list; do \
     if test -f "$$i"; then echo $$i; else echo $(srcdir)/$$i; fi; \
   done | $(am__uniquify_input)`
-ETAGS = etags
-CTAGS = ctags
 am__DIST_COMMON = $(srcdir)/Makefile.in \
 	$(top_srcdir)/conftools/depcomp
 DISTFILES = $(DIST_COMMON) $(DIST_SOURCES) $(TEXINFOS) $(EXTRA_DIST)
 ACLOCAL = @ACLOCAL@
 AMTAR = @AMTAR@
+AM_CFLAGS = @AM_CFLAGS@
+AM_CPPFLAGS = @AM_CPPFLAGS@ -I$(srcdir)/../lib
+AM_CXXFLAGS = @AM_CXXFLAGS@
 AM_DEFAULT_VERBOSITY = @AM_DEFAULT_VERBOSITY@
+AM_LDFLAGS = @AM_LDFLAGS@
 AR = @AR@
 AS = @AS@
 AUTOCONF = @AUTOCONF@
@@ -227,8 +230,9 @@ AWK = @AWK@
 CC = @CC@
 CCDEPMODE = @CCDEPMODE@
 CFLAGS = @CFLAGS@
-CPP = @CPP@
 CPPFLAGS = @CPPFLAGS@
+CSCOPE = @CSCOPE@
+CTAGS = @CTAGS@
 CXX = @CXX@
 CXXCPP = @CXXCPP@
 CXXDEPMODE = @CXXDEPMODE@
@@ -244,7 +248,15 @@ ECHO_C = @ECHO_C@
 ECHO_N = @ECHO_N@
 ECHO_T = @ECHO_T@
 EGREP = @EGREP@
+ETAGS = @ETAGS@
 EXEEXT = @EXEEXT@
+EXPAT_ATTR_INFO = @EXPAT_ATTR_INFO@
+EXPAT_CHAR_TYPE = @EXPAT_CHAR_TYPE@
+EXPAT_CONTEXT_BYTES = @EXPAT_CONTEXT_BYTES@
+EXPAT_DTD = @EXPAT_DTD@
+EXPAT_LARGE_SIZE = @EXPAT_LARGE_SIZE@
+EXPAT_MIN_SIZE = @EXPAT_MIN_SIZE@
+EXPAT_NS = @EXPAT_NS@
 FGREP = @FGREP@
 FILEMAP = @FILEMAP@
 GREP = @GREP@
@@ -257,6 +269,8 @@ LD = @LD@
 LDFLAGS = @LDFLAGS@
 LIBAGE = @LIBAGE@
 LIBCURRENT = @LIBCURRENT@
+LIBDIR_BASENAME = @LIBDIR_BASENAME@
+LIBM = @LIBM@
 LIBOBJS = @LIBOBJS@
 LIBREVISION = @LIBREVISION@
 LIBS = @LIBS@
@@ -286,6 +300,9 @@ RANLIB = @RANLIB@
 SED = @SED@
 SET_MAKE = @SET_MAKE@
 SHELL = @SHELL@
+SO_MAJOR = @SO_MAJOR@
+SO_MINOR = @SO_MINOR@
+SO_PATCH = @SO_PATCH@
 STRIP = @STRIP@
 VERSION = @VERSION@
 abs_builddir = @abs_builddir@
@@ -296,6 +313,7 @@ ac_ct_AR = @ac_ct_AR@
 ac_ct_CC = @ac_ct_CC@
 ac_ct_CXX = @ac_ct_CXX@
 ac_ct_DUMPBIN = @ac_ct_DUMPBIN@
+ac_cv_sizeof_void_p = @ac_cv_sizeof_void_p@
 am__include = @am__include@
 am__leading_dot = @am__leading_dot@
 am__quote = @am__quote@
@@ -333,6 +351,7 @@ pdfdir = @pdfdir@
 prefix = @prefix@
 program_transform_name = @program_transform_name@
 psdir = @psdir@
+runstatedir = @runstatedir@
 sbindir = @sbindir@
 sharedstatedir = @sharedstatedir@
 srcdir = @srcdir@
@@ -341,7 +360,6 @@ target_alias = @target_alias@
 top_build_prefix = @top_build_prefix@
 top_builddir = @top_builddir@
 top_srcdir = @top_srcdir@
-AM_CPPFLAGS = -I$(srcdir)/../lib
 elements_SOURCES = elements.c
 elements_LDADD = ../lib/libexpat.la
 outline_SOURCES = outline.c
@@ -490,7 +508,6 @@ cscopelist-am: $(am__tagged_files)
 
 distclean-tags:
 	-rm -f TAGS ID GTAGS GRTAGS GSYMS GPATH tags
-
 distdir: $(BUILT_SOURCES)
 	$(MAKE) $(AM_MAKEFLAGS) distdir-am
 
diff --git a/contrib/expat/examples/elements.c b/contrib/expat/examples/elements.c
index eb0c729bff15..2b6645610771 100644
--- a/contrib/expat/examples/elements.c
+++ b/contrib/expat/examples/elements.c
@@ -11,7 +11,12 @@
                                  |_| XML parser
 
    Copyright (c) 1997-2000 Thai Open Source Software Center Ltd
-   Copyright (c) 2000-2017 Expat development team
+   Copyright (c) 2001-2003 Fred L. Drake, Jr. <fdrake@users.sourceforge.net>
+   Copyright (c) 2004-2006 Karl Waclawek <karl@waclawek.net>
+   Copyright (c) 2005-2007 Steven Solie <ssolie@users.sourceforge.net>
+   Copyright (c) 2016-2019 Sebastian Pipping <sebastian@pipping.org>
+   Copyright (c) 2017      Rhodri James <rhodri@wildebeest.org.uk>
+   Copyright (c) 2019      Zhongyuan Zhou <zhouzhongyuan@huawei.com>
    Licensed under the MIT license:
 
    Permission is  hereby granted,  free of charge,  to any  person obtaining
diff --git a/contrib/expat/examples/outline.c b/contrib/expat/examples/outline.c
index d996b8e3a8d3..4ed041febb37 100644
--- a/contrib/expat/examples/outline.c
+++ b/contrib/expat/examples/outline.c
@@ -8,8 +8,12 @@
                         \___/_/\_\ .__/ \__,_|\__|
                                  |_| XML parser
 
-   Copyright (c) 1997-2000 Thai Open Source Software Center Ltd
-   Copyright (c) 2000-2017 Expat development team
+   Copyright (c) 2000      Clark Cooper <coopercc@users.sourceforge.net>
+   Copyright (c) 2001-2003 Fred L. Drake, Jr. <fdrake@users.sourceforge.net>
+   Copyright (c) 2005-2007 Steven Solie <ssolie@users.sourceforge.net>
+   Copyright (c) 2005-2006 Karl Waclawek <karl@waclawek.net>
+   Copyright (c) 2016-2019 Sebastian Pipping <sebastian@pipping.org>
+   Copyright (c) 2017      Rhodri James <rhodri@wildebeest.org.uk>
    Licensed under the MIT license:
 
    Permission is  hereby granted,  free of charge,  to any  person obtaining
diff --git a/contrib/expat/expat_config.h.in b/contrib/expat/expat_config.h.in
index 59207b42e41d..ec068caab89c 100644
--- a/contrib/expat/expat_config.h.in
+++ b/contrib/expat/expat_config.h.in
@@ -30,15 +30,15 @@
 /* Define to 1 if you have the `bsd' library (-lbsd). */
 #undef HAVE_LIBBSD
 
-/* Define to 1 if you have the <memory.h> header file. */
-#undef HAVE_MEMORY_H
-
 /* Define to 1 if you have a working `mmap' system call. */
 #undef HAVE_MMAP
 
 /* Define to 1 if you have the <stdint.h> header file. */
 #undef HAVE_STDINT_H
 
+/* Define to 1 if you have the <stdio.h> header file. */
+#undef HAVE_STDIO_H
+
 /* Define to 1 if you have the <stdlib.h> header file. */
 #undef HAVE_STDLIB_H
 
@@ -87,7 +87,9 @@
 /* Define to the version of this package. */
 #undef PACKAGE_VERSION
 
-/* Define to 1 if you have the ANSI C header files. */
+/* Define to 1 if all of the C90 standard headers exist (not just the ones
+   required in a freestanding environment). This macro is provided for
+   backward compatibility; new code need not use it. */
 #undef STDC_HEADERS
 
 /* Version number of package */
diff --git a/contrib/expat/fix-xmltest-log.sh b/contrib/expat/fix-xmltest-log.sh
index c143e93cf20a..164ea4e3597f 100755
--- a/contrib/expat/fix-xmltest-log.sh
+++ b/contrib/expat/fix-xmltest-log.sh
@@ -6,7 +6,7 @@
 #                      \___/_/\_\ .__/ \__,_|\__|
 #                               |_| XML parser
 #
-# Copyright (c) 2019 Expat development team
+# Copyright (c) 2019 Sebastian Pipping <sebastian@pipping.org>
 # Licensed under the MIT license:
 #
 # Permission is  hereby granted,  free of charge,  to any  person obtaining
diff --git a/contrib/expat/fuzz/xml_parse_fuzzer.c b/contrib/expat/fuzz/xml_parse_fuzzer.c
new file mode 100644
index 000000000000..48b50212fa62
--- /dev/null
+++ b/contrib/expat/fuzz/xml_parse_fuzzer.c
@@ -0,0 +1,64 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <assert.h>
+#include <stdint.h>
+
+#include "expat.h"
+#include "siphash.h"
+
+// Macros to convert preprocessor macros to string literals. See
+// https://gcc.gnu.org/onlinedocs/gcc-3.4.3/cpp/Stringification.html
+#define xstr(s) str(s)
+#define str(s) #s
+
+// The encoder type that we wish to fuzz should come from the compile-time
+// definition `ENCODING_FOR_FUZZING`. This allows us to have a separate fuzzer
+// binary for
+#ifndef ENCODING_FOR_FUZZING
+#  error "ENCODING_FOR_FUZZING was not provided to this fuzz target."
+#endif
+
+// 16-byte deterministic hash key.
+static unsigned char hash_key[16] = "FUZZING IS FUN!";
+
+static void XMLCALL
+start(void *userData, const XML_Char *name, const XML_Char **atts) {
+  (void)userData;
+  (void)name;
+  (void)atts;
+}
+static void XMLCALL
+end(void *userData, const XML_Char *name) {
+  (void)userData;
+  (void)name;
+}
+
+int
+LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
+  XML_Parser p = XML_ParserCreate(xstr(ENCODING_FOR_FUZZING));
+  assert(p);
+
+  // Set the hash salt using siphash to generate a deterministic hash.
+  struct sipkey *key = sip_keyof(hash_key);
+  XML_SetHashSalt(p, (unsigned long)siphash24(data, size, key));
+
+  XML_SetElementHandler(p, start, end);
+  XML_Parse(p, (const XML_Char *)data, size, 0);
+  XML_Parse(p, (const XML_Char *)data, size, 1);
+  XML_ParserFree(p);
+  return 0;
+}
diff --git a/contrib/expat/fuzz/xml_parsebuffer_fuzzer.c b/contrib/expat/fuzz/xml_parsebuffer_fuzzer.c
new file mode 100644
index 000000000000..0c7a8f2bf4fc
--- /dev/null
+++ b/contrib/expat/fuzz/xml_parsebuffer_fuzzer.c
@@ -0,0 +1,71 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <assert.h>
+#include <stdint.h>
+#include <string.h>
+
+#include "expat.h"
+#include "siphash.h"
+
+// Macros to convert preprocessor macros to string literals. See
+// https://gcc.gnu.org/onlinedocs/gcc-3.4.3/cpp/Stringification.html
+#define xstr(s) str(s)
+#define str(s) #s
+
+// The encoder type that we wish to fuzz should come from the compile-time
+// definition `ENCODING_FOR_FUZZING`. This allows us to have a separate fuzzer
+// binary for
+#ifndef ENCODING_FOR_FUZZING
+#  error "ENCODING_FOR_FUZZING was not provided to this fuzz target."
+#endif
+
+// 16-byte deterministic hash key.
+static unsigned char hash_key[16] = "FUZZING IS FUN!";
+
+static void XMLCALL
+start(void *userData, const XML_Char *name, const XML_Char **atts) {
+  (void)userData;
+  (void)name;
+  (void)atts;
+}
+static void XMLCALL
+end(void *userData, const XML_Char *name) {
+  (void)userData;
+  (void)name;
+}
+
+int
+LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
+  if (size == 0)
+    return 0;
+
+  XML_Parser p = XML_ParserCreate(xstr(ENCODING_FOR_FUZZING));
+  assert(p);
+  XML_SetElementHandler(p, start, end);
+
+  // Set the hash salt using siphash to generate a deterministic hash.
+  struct sipkey *key = sip_keyof(hash_key);
+  XML_SetHashSalt(p, (unsigned long)siphash24(data, size, key));
+
+  void *buf = XML_GetBuffer(p, size);
+  assert(buf);
+
+  memcpy(buf, data, size);
+  XML_ParseBuffer(p, size, size == 0);
+  XML_ParserFree(p);
+  return 0;
+}
diff --git a/contrib/expat/lib/Makefile.am b/contrib/expat/lib/Makefile.am
index 8cb451ed4647..d5402496a299 100644
--- a/contrib/expat/lib/Makefile.am
+++ b/contrib/expat/lib/Makefile.am
@@ -6,7 +6,9 @@
 #                      \___/_/\_\ .__/ \__,_|\__|
 #                               |_| XML parser
 #
-# Copyright (c) 2017 Expat development team
+# Copyright (c) 2017-2021 Sebastian Pipping <sebastian@pipping.org>
+# Copyright (c) 2017      Tomasz Kłoczko <kloczek@fedoraproject.org>
+# Copyright (c) 2019      David Loffredo <loffredo@steptools.com>
 # Licensed under the MIT license:
 #
 # Permission is  hereby granted,  free of charge,  to any  person obtaining
@@ -34,16 +36,26 @@ include_HEADERS = \
     expat_external.h
 
 lib_LTLIBRARIES = libexpat.la
+noinst_LTLIBRARIES = libexpatinternal.la
 
 libexpat_la_LDFLAGS = \
+    @AM_LDFLAGS@ \
+    @LIBM@ \
     -no-undefined \
     -version-info @LIBCURRENT@:@LIBREVISION@:@LIBAGE@
 
-libexpat_la_SOURCES = \
+libexpat_la_SOURCES =
+
+# This layer of indirection allows
+# the test suite to access internal symbols
+# despite compiling with -fvisibility=hidden
+libexpatinternal_la_SOURCES = \
     xmlparse.c \
     xmltok.c \
     xmlrole.c
 
+libexpat_la_LIBADD = libexpatinternal.la
+
 doc_DATA = \
     ../AUTHORS \
     ../Changes
diff --git a/contrib/expat/lib/Makefile.in b/contrib/expat/lib/Makefile.in
index bbd6a1885fc8..d4069ebe983d 100644
--- a/contrib/expat/lib/Makefile.in
+++ b/contrib/expat/lib/Makefile.in
@@ -1,7 +1,7 @@
-# Makefile.in generated by automake 1.16.1 from Makefile.am.
+# Makefile.in generated by automake 1.16.5 from Makefile.am.
 # @configure_input@
 
-# Copyright (C) 1994-2018 Free Software Foundation, Inc.
+# Copyright (C) 1994-2021 Free Software Foundation, Inc.
 
 # This Makefile.in is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
@@ -22,7 +22,9 @@
 #                      \___/_/\_\ .__/ \__,_|\__|
 #                               |_| XML parser
 #
-# Copyright (c) 2017 Expat development team
+# Copyright (c) 2017-2021 Sebastian Pipping <sebastian@pipping.org>
+# Copyright (c) 2017      Tomasz Kłoczko <kloczek@fedoraproject.org>
+# Copyright (c) 2019      David Loffredo <loffredo@steptools.com>
 # Licensed under the MIT license:
 #
 # Permission is  hereby granted,  free of charge,  to any  person obtaining
@@ -171,9 +173,9 @@ am__uninstall_files_from_dir = { \
   }
 am__installdirs = "$(DESTDIR)$(libdir)" "$(DESTDIR)$(docdir)" \
 	"$(DESTDIR)$(includedir)"
-LTLIBRARIES = $(lib_LTLIBRARIES)
-libexpat_la_LIBADD =
-am_libexpat_la_OBJECTS = xmlparse.lo xmltok.lo xmlrole.lo
+LTLIBRARIES = $(lib_LTLIBRARIES) $(noinst_LTLIBRARIES)
+libexpat_la_DEPENDENCIES = libexpatinternal.la
+am_libexpat_la_OBJECTS =
 libexpat_la_OBJECTS = $(am_libexpat_la_OBJECTS)
 AM_V_lt = $(am__v_lt_@AM_V@)
 am__v_lt_ = $(am__v_lt_@AM_DEFAULT_V@)
@@ -182,6 +184,9 @@ am__v_lt_1 =
 libexpat_la_LINK = $(LIBTOOL) $(AM_V_lt) --tag=CC $(AM_LIBTOOLFLAGS) \
 	$(LIBTOOLFLAGS) --mode=link $(CCLD) $(AM_CFLAGS) $(CFLAGS) \
 	$(libexpat_la_LDFLAGS) $(LDFLAGS) -o $@
+libexpatinternal_la_LIBADD =
+am_libexpatinternal_la_OBJECTS = xmlparse.lo xmltok.lo xmlrole.lo
+libexpatinternal_la_OBJECTS = $(am_libexpatinternal_la_OBJECTS)
 AM_V_P = $(am__v_P_@AM_V@)
 am__v_P_ = $(am__v_P_@AM_DEFAULT_V@)
 am__v_P_0 = false
@@ -218,8 +223,8 @@ AM_V_CCLD = $(am__v_CCLD_@AM_V@)
 am__v_CCLD_ = $(am__v_CCLD_@AM_DEFAULT_V@)
 am__v_CCLD_0 = @echo "  CCLD    " $@;
 am__v_CCLD_1 = 
-SOURCES = $(libexpat_la_SOURCES)
-DIST_SOURCES = $(libexpat_la_SOURCES)
+SOURCES = $(libexpat_la_SOURCES) $(libexpatinternal_la_SOURCES)
+DIST_SOURCES = $(libexpat_la_SOURCES) $(libexpatinternal_la_SOURCES)
 am__can_run_installinfo = \
   case $$AM_UPDATE_INFO_DIR in \
     n|no|NO) false;; \
@@ -244,14 +249,16 @@ am__define_uniq_tagged_files = \
   unique=`for i in $$list; do \
     if test -f "$$i"; then echo $$i; else echo $(srcdir)/$$i; fi; \
   done | $(am__uniquify_input)`
-ETAGS = etags
-CTAGS = ctags
 am__DIST_COMMON = $(srcdir)/Makefile.in \
 	$(top_srcdir)/conftools/depcomp
 DISTFILES = $(DIST_COMMON) $(DIST_SOURCES) $(TEXINFOS) $(EXTRA_DIST)
 ACLOCAL = @ACLOCAL@
 AMTAR = @AMTAR@
+AM_CFLAGS = @AM_CFLAGS@
+AM_CPPFLAGS = @AM_CPPFLAGS@
+AM_CXXFLAGS = @AM_CXXFLAGS@
 AM_DEFAULT_VERBOSITY = @AM_DEFAULT_VERBOSITY@
+AM_LDFLAGS = @AM_LDFLAGS@
 AR = @AR@
 AS = @AS@
 AUTOCONF = @AUTOCONF@
@@ -261,8 +268,9 @@ AWK = @AWK@
 CC = @CC@
 CCDEPMODE = @CCDEPMODE@
 CFLAGS = @CFLAGS@
-CPP = @CPP@
 CPPFLAGS = @CPPFLAGS@
+CSCOPE = @CSCOPE@
+CTAGS = @CTAGS@
 CXX = @CXX@
 CXXCPP = @CXXCPP@
 CXXDEPMODE = @CXXDEPMODE@
@@ -278,7 +286,15 @@ ECHO_C = @ECHO_C@
 ECHO_N = @ECHO_N@
 ECHO_T = @ECHO_T@
 EGREP = @EGREP@
+ETAGS = @ETAGS@
 EXEEXT = @EXEEXT@
+EXPAT_ATTR_INFO = @EXPAT_ATTR_INFO@
+EXPAT_CHAR_TYPE = @EXPAT_CHAR_TYPE@
+EXPAT_CONTEXT_BYTES = @EXPAT_CONTEXT_BYTES@
+EXPAT_DTD = @EXPAT_DTD@
+EXPAT_LARGE_SIZE = @EXPAT_LARGE_SIZE@
+EXPAT_MIN_SIZE = @EXPAT_MIN_SIZE@
+EXPAT_NS = @EXPAT_NS@
 FGREP = @FGREP@
 FILEMAP = @FILEMAP@
 GREP = @GREP@
@@ -291,6 +307,8 @@ LD = @LD@
 LDFLAGS = @LDFLAGS@
 LIBAGE = @LIBAGE@
 LIBCURRENT = @LIBCURRENT@
+LIBDIR_BASENAME = @LIBDIR_BASENAME@
+LIBM = @LIBM@
 LIBOBJS = @LIBOBJS@
 LIBREVISION = @LIBREVISION@
 LIBS = @LIBS@
@@ -320,6 +338,9 @@ RANLIB = @RANLIB@
 SED = @SED@
 SET_MAKE = @SET_MAKE@
 SHELL = @SHELL@
+SO_MAJOR = @SO_MAJOR@
+SO_MINOR = @SO_MINOR@
+SO_PATCH = @SO_PATCH@
 STRIP = @STRIP@
 VERSION = @VERSION@
 abs_builddir = @abs_builddir@
@@ -330,6 +351,7 @@ ac_ct_AR = @ac_ct_AR@
 ac_ct_CC = @ac_ct_CC@
 ac_ct_CXX = @ac_ct_CXX@
 ac_ct_DUMPBIN = @ac_ct_DUMPBIN@
+ac_cv_sizeof_void_p = @ac_cv_sizeof_void_p@
 am__include = @am__include@
 am__leading_dot = @am__leading_dot@
 am__quote = @am__quote@
@@ -367,6 +389,7 @@ pdfdir = @pdfdir@
 prefix = @prefix@
 program_transform_name = @program_transform_name@
 psdir = @psdir@
+runstatedir = @runstatedir@
 sbindir = @sbindir@
 sharedstatedir = @sharedstatedir@
 srcdir = @srcdir@
@@ -381,15 +404,24 @@ include_HEADERS = \
     expat_external.h
 
 lib_LTLIBRARIES = libexpat.la
+noinst_LTLIBRARIES = libexpatinternal.la
 libexpat_la_LDFLAGS = \
+    @AM_LDFLAGS@ \
+    @LIBM@ \
     -no-undefined \
     -version-info @LIBCURRENT@:@LIBREVISION@:@LIBAGE@
 
-libexpat_la_SOURCES = \
+libexpat_la_SOURCES = 
+
+# This layer of indirection allows
+# the test suite to access internal symbols
+# despite compiling with -fvisibility=hidden
+libexpatinternal_la_SOURCES = \
     xmlparse.c \
     xmltok.c \
     xmlrole.c
 
+libexpat_la_LIBADD = libexpatinternal.la
 doc_DATA = \
     ../AUTHORS \
     ../Changes
@@ -483,9 +515,23 @@ clean-libLTLIBRARIES:
 	  rm -f $${locs}; \
 	}
 
+clean-noinstLTLIBRARIES:
+	-test -z "$(noinst_LTLIBRARIES)" || rm -f $(noinst_LTLIBRARIES)
+	@list='$(noinst_LTLIBRARIES)'; \
+	locs=`for p in $$list; do echo $$p; done | \
+	      sed 's|^[^/]*$$|.|; s|/[^/]*$$||; s|$$|/so_locations|' | \
+	      sort -u`; \
+	test -z "$$locs" || { \
+	  echo rm -f $${locs}; \
+	  rm -f $${locs}; \
+	}
+
 libexpat.la: $(libexpat_la_OBJECTS) $(libexpat_la_DEPENDENCIES) $(EXTRA_libexpat_la_DEPENDENCIES) 
 	$(AM_V_CCLD)$(libexpat_la_LINK) -rpath $(libdir) $(libexpat_la_OBJECTS) $(libexpat_la_LIBADD) $(LIBS)
 
+libexpatinternal.la: $(libexpatinternal_la_OBJECTS) $(libexpatinternal_la_DEPENDENCIES) $(EXTRA_libexpatinternal_la_DEPENDENCIES) 
+	$(AM_V_CCLD)$(LINK)  $(libexpatinternal_la_OBJECTS) $(libexpatinternal_la_LIBADD) $(LIBS)
+
 mostlyclean-compile:
 	-rm -f *.$(OBJEXT)
 
@@ -622,7 +668,6 @@ cscopelist-am: $(am__tagged_files)
 
 distclean-tags:
 	-rm -f TAGS ID GTAGS GRTAGS GSYMS GPATH tags
-
 distdir: $(BUILT_SOURCES)
 	$(MAKE) $(AM_MAKEFLAGS) distdir-am
 
@@ -696,7 +741,7 @@ maintainer-clean-generic:
 clean: clean-am
 
 clean-am: clean-generic clean-libLTLIBRARIES clean-libtool \
-	mostlyclean-am
+	clean-noinstLTLIBRARIES mostlyclean-am
 
 distclean: distclean-am
 		-rm -f ./$(DEPDIR)/xmlparse.Plo
@@ -773,16 +818,17 @@ uninstall-am: uninstall-docDATA uninstall-includeHEADERS \
 .MAKE: install-am install-data-am install-strip
 
 .PHONY: CTAGS GTAGS TAGS all all-am am--depfiles check check-am clean \
-	clean-generic clean-libLTLIBRARIES clean-libtool cscopelist-am \
-	ctags ctags-am distclean distclean-compile distclean-generic \
-	distclean-libtool distclean-tags distdir dvi dvi-am html \
-	html-am info info-am install install-am install-data \
-	install-data-am install-data-hook install-docDATA install-dvi \
-	install-dvi-am install-exec install-exec-am install-html \
-	install-html-am install-includeHEADERS install-info \
-	install-info-am install-libLTLIBRARIES install-man install-pdf \
-	install-pdf-am install-ps install-ps-am install-strip \
-	installcheck installcheck-am installdirs maintainer-clean \
+	clean-generic clean-libLTLIBRARIES clean-libtool \
+	clean-noinstLTLIBRARIES cscopelist-am ctags ctags-am distclean \
+	distclean-compile distclean-generic distclean-libtool \
+	distclean-tags distdir dvi dvi-am html html-am info info-am \
+	install install-am install-data install-data-am \
+	install-data-hook install-docDATA install-dvi install-dvi-am \
+	install-exec install-exec-am install-html install-html-am \
+	install-includeHEADERS install-info install-info-am \
+	install-libLTLIBRARIES install-man install-pdf install-pdf-am \
+	install-ps install-ps-am install-strip installcheck \
+	installcheck-am installdirs maintainer-clean \
 	maintainer-clean-generic mostlyclean mostlyclean-compile \
 	mostlyclean-generic mostlyclean-libtool pdf pdf-am ps ps-am \
 	tags tags-am uninstall uninstall-am uninstall-docDATA \
diff --git a/contrib/expat/lib/ascii.h b/contrib/expat/lib/ascii.h
index c3587e57332b..1f594d2e54b4 100644
--- a/contrib/expat/lib/ascii.h
+++ b/contrib/expat/lib/ascii.h
@@ -6,8 +6,11 @@
                         \___/_/\_\ .__/ \__,_|\__|
                                  |_| XML parser
 
-   Copyright (c) 1997-2000 Thai Open Source Software Center Ltd
-   Copyright (c) 2000-2017 Expat development team
+   Copyright (c) 1999-2000 Thai Open Source Software Center Ltd
+   Copyright (c) 2000      Clark Cooper <coopercc@users.sourceforge.net>
+   Copyright (c) 2002      Fred L. Drake, Jr. <fdrake@users.sourceforge.net>
+   Copyright (c) 2007      Karl Waclawek <karl@waclawek.net>
+   Copyright (c) 2017      Sebastian Pipping <sebastian@pipping.org>
    Licensed under the MIT license:
 
    Permission is  hereby granted,  free of charge,  to any  person obtaining
diff --git a/contrib/expat/lib/asciitab.h b/contrib/expat/lib/asciitab.h
index 63b1d1b4482e..af766fb24785 100644
--- a/contrib/expat/lib/asciitab.h
+++ b/contrib/expat/lib/asciitab.h
@@ -7,7 +7,9 @@
                                  |_| XML parser
 
    Copyright (c) 1997-2000 Thai Open Source Software Center Ltd
-   Copyright (c) 2000-2017 Expat development team
+   Copyright (c) 2000      Clark Cooper <coopercc@users.sourceforge.net>
+   Copyright (c) 2002      Fred L. Drake, Jr. <fdrake@users.sourceforge.net>
+   Copyright (c) 2017      Sebastian Pipping <sebastian@pipping.org>
    Licensed under the MIT license:
 
    Permission is  hereby granted,  free of charge,  to any  person obtaining
diff --git a/contrib/expat/lib/expat.h b/contrib/expat/lib/expat.h
index 48a6e2a32917..0f021e25def1 100644
--- a/contrib/expat/lib/expat.h
+++ b/contrib/expat/lib/expat.h
@@ -7,7 +7,14 @@
                                  |_| XML parser
 
    Copyright (c) 1997-2000 Thai Open Source Software Center Ltd
-   Copyright (c) 2000-2017 Expat development team
+   Copyright (c) 2000      Clark Cooper <coopercc@users.sourceforge.net>
+   Copyright (c) 2000-2005 Fred L. Drake, Jr. <fdrake@users.sourceforge.net>
+   Copyright (c) 2001-2002 Greg Stein <gstein@users.sourceforge.net>
+   Copyright (c) 2002-2016 Karl Waclawek <karl@waclawek.net>
+   Copyright (c) 2016-2022 Sebastian Pipping <sebastian@pipping.org>
+   Copyright (c) 2016      Cristian Rodríguez <crrodriguez@opensuse.org>
+   Copyright (c) 2016      Thomas Beutlich <tc@tbeu.de>
+   Copyright (c) 2017      Rhodri James <rhodri@wildebeest.org.uk>
    Licensed under the MIT license:
 
    Permission is  hereby granted,  free of charge,  to any  person obtaining
@@ -115,7 +122,11 @@ enum XML_Error {
   XML_ERROR_RESERVED_PREFIX_XMLNS,
   XML_ERROR_RESERVED_NAMESPACE_URI,
   /* Added in 2.2.1. */
-  XML_ERROR_INVALID_ARGUMENT
+  XML_ERROR_INVALID_ARGUMENT,
+  /* Added in 2.3.0. */
+  XML_ERROR_NO_BUFFER,
+  /* Added in 2.4.0. */
+  XML_ERROR_AMPLIFICATION_LIMIT_BREACH
 };
 
 enum XML_Content_Type {
@@ -318,7 +329,7 @@ typedef void(XMLCALL *XML_EndDoctypeDeclHandler)(void *userData);
 
    For internal entities (<!ENTITY foo "bar">), value will
    be non-NULL and systemId, publicID, and notationName will be NULL.
-   The value string is NOT nul-terminated; the length is provided in
+   The value string is NOT null-terminated; the length is provided in
    the value_length argument. Since it is legal to have zero-length
    values, do not use this argument to test for internal entities.
 
@@ -513,7 +524,7 @@ typedef struct {
    Otherwise it must return XML_STATUS_ERROR.
 
    If info does not describe a suitable encoding, then the parser will
-   return an XML_UNKNOWN_ENCODING error.
+   return an XML_ERROR_UNKNOWN_ENCODING error.
 */
 typedef int(XMLCALL *XML_UnknownEncodingHandler)(void *encodingHandlerData,
                                                  const XML_Char *name,
@@ -707,7 +718,7 @@ XML_GetBase(XML_Parser parser);
 /* Returns the number of the attribute/value pairs passed in last call
    to the XML_StartElementHandler that were specified in the start-tag
    rather than defaulted. Each attribute/value pair counts as 2; thus
-   this correspondds to an index into the atts array passed to the
+   this corresponds to an index into the atts array passed to the
    XML_StartElementHandler.  Returns -1 if parser == NULL.
 */
 XMLPARSEAPI(int)
@@ -716,7 +727,7 @@ XML_GetSpecifiedAttributeCount(XML_Parser parser);
 /* Returns the index of the ID attribute passed in the last call to
    XML_StartElementHandler, or -1 if there is no ID attribute or
    parser == NULL.  Each attribute/value pair counts as 2; thus this
-   correspondds to an index into the atts array passed to the
+   corresponds to an index into the atts array passed to the
    XML_StartElementHandler.
 */
 XMLPARSEAPI(int)
@@ -997,7 +1008,10 @@ enum XML_FeatureEnum {
   XML_FEATURE_SIZEOF_XML_LCHAR,
   XML_FEATURE_NS,
   XML_FEATURE_LARGE_SIZE,
-  XML_FEATURE_ATTR_INFO
+  XML_FEATURE_ATTR_INFO,
+  /* Added in Expat 2.4.0. */
+  XML_FEATURE_BILLION_LAUGHS_ATTACK_PROTECTION_MAXIMUM_AMPLIFICATION_DEFAULT,
+  XML_FEATURE_BILLION_LAUGHS_ATTACK_PROTECTION_ACTIVATION_THRESHOLD_DEFAULT
   /* Additional features must be added to the end of this enum. */
 };
 
@@ -1010,12 +1024,24 @@ typedef struct {
 XMLPARSEAPI(const XML_Feature *)
 XML_GetFeatureList(void);
 
+#ifdef XML_DTD
+/* Added in Expat 2.4.0. */
+XMLPARSEAPI(XML_Bool)
+XML_SetBillionLaughsAttackProtectionMaximumAmplification(
+    XML_Parser parser, float maximumAmplificationFactor);
+
+/* Added in Expat 2.4.0. */
+XMLPARSEAPI(XML_Bool)
+XML_SetBillionLaughsAttackProtectionActivationThreshold(
+    XML_Parser parser, unsigned long long activationThresholdBytes);
+#endif
+
 /* Expat follows the semantic versioning convention.
    See http://semver.org.
 */
 #define XML_MAJOR_VERSION 2
-#define XML_MINOR_VERSION 2
-#define XML_MICRO_VERSION 9
+#define XML_MINOR_VERSION 4
+#define XML_MICRO_VERSION 3
 
 #ifdef __cplusplus
 }
diff --git a/contrib/expat/lib/expat_external.h b/contrib/expat/lib/expat_external.h
index b3b6e74d9d20..8829f7709104 100644
--- a/contrib/expat/lib/expat_external.h
+++ b/contrib/expat/lib/expat_external.h
@@ -7,7 +7,14 @@
                                  |_| XML parser
 
    Copyright (c) 1997-2000 Thai Open Source Software Center Ltd
-   Copyright (c) 2000-2017 Expat development team
+   Copyright (c) 2000      Clark Cooper <coopercc@users.sourceforge.net>
+   Copyright (c) 2000-2004 Fred L. Drake, Jr. <fdrake@users.sourceforge.net>
+   Copyright (c) 2001-2002 Greg Stein <gstein@users.sourceforge.net>
+   Copyright (c) 2002-2006 Karl Waclawek <karl@waclawek.net>
+   Copyright (c) 2016      Cristian Rodríguez <crrodriguez@opensuse.org>
+   Copyright (c) 2016-2019 Sebastian Pipping <sebastian@pipping.org>
+   Copyright (c) 2017      Rhodri James <rhodri@wildebeest.org.uk>
+   Copyright (c) 2018      Yury Gribov <tetra2005@gmail.com>
    Licensed under the MIT license:
 
    Permission is  hereby granted,  free of charge,  to any  person obtaining
diff --git a/contrib/expat/lib/iasciitab.h b/contrib/expat/lib/iasciitab.h
index ea97cfcf678e..5d8646f2a318 100644
--- a/contrib/expat/lib/iasciitab.h
+++ b/contrib/expat/lib/iasciitab.h
@@ -7,7 +7,9 @@
                                  |_| XML parser
 
    Copyright (c) 1997-2000 Thai Open Source Software Center Ltd
-   Copyright (c) 2000-2017 Expat development team
+   Copyright (c) 2000      Clark Cooper <coopercc@users.sourceforge.net>
+   Copyright (c) 2002      Fred L. Drake, Jr. <fdrake@users.sourceforge.net>
+   Copyright (c) 2017      Sebastian Pipping <sebastian@pipping.org>
    Licensed under the MIT license:
 
    Permission is  hereby granted,  free of charge,  to any  person obtaining
diff --git a/contrib/expat/lib/internal.h b/contrib/expat/lib/internal.h
index 60913dab762f..444eba0fb031 100644
--- a/contrib/expat/lib/internal.h
+++ b/contrib/expat/lib/internal.h
@@ -25,8 +25,12 @@
                         \___/_/\_\ .__/ \__,_|\__|
                                  |_| XML parser
 
-   Copyright (c) 1997-2000 Thai Open Source Software Center Ltd
-   Copyright (c) 2000-2017 Expat development team
+   Copyright (c) 2002-2003 Fred L. Drake, Jr. <fdrake@users.sourceforge.net>
+   Copyright (c) 2002-2006 Karl Waclawek <karl@waclawek.net>
+   Copyright (c) 2003      Greg Stein <gstein@users.sourceforge.net>
+   Copyright (c) 2016-2021 Sebastian Pipping <sebastian@pipping.org>
+   Copyright (c) 2018      Yury Gribov <tetra2005@gmail.com>
+   Copyright (c) 2019      David Loffredo <loffredo@steptools.com>
    Licensed under the MIT license:
 
    Permission is  hereby granted,  free of charge,  to any  person obtaining
@@ -101,22 +105,58 @@
 #  endif
 #endif
 
+#include <limits.h> // ULONG_MAX
+
+#if defined(_WIN32) && ! defined(__USE_MINGW_ANSI_STDIO)
+#  define EXPAT_FMT_ULL(midpart) "%" midpart "I64u"
+#  if defined(_WIN64) // Note: modifiers "td" and "zu" do not work for MinGW
+#    define EXPAT_FMT_PTRDIFF_T(midpart) "%" midpart "I64d"
+#    define EXPAT_FMT_SIZE_T(midpart) "%" midpart "I64u"
+#  else
+#    define EXPAT_FMT_PTRDIFF_T(midpart) "%" midpart "d"
+#    define EXPAT_FMT_SIZE_T(midpart) "%" midpart "u"
+#  endif
+#else
+#  define EXPAT_FMT_ULL(midpart) "%" midpart "llu"
+#  if ! defined(ULONG_MAX)
+#    error Compiler did not define ULONG_MAX for us
+#  elif ULONG_MAX == 18446744073709551615u // 2^64-1
+#    define EXPAT_FMT_PTRDIFF_T(midpart) "%" midpart "ld"
+#    define EXPAT_FMT_SIZE_T(midpart) "%" midpart "lu"
+#  else
+#    define EXPAT_FMT_PTRDIFF_T(midpart) "%" midpart "d"
+#    define EXPAT_FMT_SIZE_T(midpart) "%" midpart "u"
+#  endif
+#endif
+
 #ifndef UNUSED_P
 #  define UNUSED_P(p) (void)p
 #endif
 
+/* NOTE BEGIN If you ever patch these defaults to greater values
+              for non-attack XML payload in your environment,
+              please file a bug report with libexpat.  Thank you!
+*/
+#define EXPAT_BILLION_LAUGHS_ATTACK_PROTECTION_MAXIMUM_AMPLIFICATION_DEFAULT   \
+  100.0f
+#define EXPAT_BILLION_LAUGHS_ATTACK_PROTECTION_ACTIVATION_THRESHOLD_DEFAULT    \
+  8388608 // 8 MiB, 2^23
+/* NOTE END */
+
+#include "expat.h" // so we can use type XML_Parser below
+
 #ifdef __cplusplus
 extern "C" {
 #endif
 
-#ifdef XML_ENABLE_VISIBILITY
-#  if XML_ENABLE_VISIBILITY
-__attribute__((visibility("default")))
-#  endif
+void _INTERNAL_trim_to_complete_utf8_characters(const char *from,
+                                                const char **fromLimRef);
+
+#if defined(XML_DTD)
+unsigned long long testingAccountingGetCountBytesDirect(XML_Parser parser);
+unsigned long long testingAccountingGetCountBytesIndirect(XML_Parser parser);
+const char *unsignedCharToPrintable(unsigned char c);
 #endif
-void
-_INTERNAL_trim_to_complete_utf8_characters(const char *from,
-                                           const char **fromLimRef);
 
 #ifdef __cplusplus
 }
diff --git a/contrib/expat/lib/latin1tab.h b/contrib/expat/lib/latin1tab.h
index 6f916041355a..b681d278af65 100644
--- a/contrib/expat/lib/latin1tab.h
+++ b/contrib/expat/lib/latin1tab.h
@@ -7,7 +7,9 @@
                                  |_| XML parser
 
    Copyright (c) 1997-2000 Thai Open Source Software Center Ltd
-   Copyright (c) 2000-2017 Expat development team
+   Copyright (c) 2000      Clark Cooper <coopercc@users.sourceforge.net>
+   Copyright (c) 2002      Fred L. Drake, Jr. <fdrake@users.sourceforge.net>
+   Copyright (c) 2017      Sebastian Pipping <sebastian@pipping.org>
    Licensed under the MIT license:
 
    Permission is  hereby granted,  free of charge,  to any  person obtaining
diff --git a/contrib/expat/lib/loadlibrary.c b/contrib/expat/lib/loadlibrary.c
deleted file mode 100644
index 35fdf98bce6c..000000000000
--- a/contrib/expat/lib/loadlibrary.c
+++ /dev/null
@@ -1,143 +0,0 @@
-/***************************************************************************
- *                                  _   _ ____  _
- *  Project                     ___| | | |  _ \| |
- *                             / __| | | | |_) | |
- *                            | (__| |_| |  _ <| |___
- *                             \___|\___/|_| \_\_____|
- *
- * Copyright (C) 2016 - 2017, Steve Holme, <steve_holme@hotmail.com>.
- * Copyright (C) 2017, Expat development team
- *
- * All rights reserved.
- * Licensed under the MIT license:
- *
- * Permission to  use, copy,  modify, and distribute  this software  for any
- * purpose with  or without fee is  hereby granted, provided that  the above
- * copyright notice and this permission notice appear in all copies.
- *
- * THE  SOFTWARE  IS  PROVIDED  "AS  IS",  WITHOUT  WARRANTY  OF  ANY  KIND,
- * EXPRESS  OR IMPLIED,  INCLUDING  BUT  NOT LIMITED  TO  THE WARRANTIES  OF
- * MERCHANTABILITY, FITNESS FOR A  PARTICULAR PURPOSE AND NONINFRINGEMENT OF
- * THIRD PARTY RIGHTS. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
- * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
- * CONTRACT, TORT OR  OTHERWISE, ARISING FROM, OUT OF OR  IN CONNECTION WITH
- * THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
- *
- * Except as contained in this notice,  the name of a copyright holder shall
- * not be used in advertising or otherwise to promote the sale, use or other
- * dealings  in this  Software without  prior written  authorization of  the
- * copyright holder.
- *
- ***************************************************************************/
-
-#if defined(_WIN32)
-
-#include <windows.h>
-#include <tchar.h>
-
-
-HMODULE _Expat_LoadLibrary(LPCTSTR filename);
-
-
-#if !defined(LOAD_WITH_ALTERED_SEARCH_PATH)
-#define LOAD_WITH_ALTERED_SEARCH_PATH  0x00000008
-#endif
-
-#if !defined(LOAD_LIBRARY_SEARCH_SYSTEM32)
-#define LOAD_LIBRARY_SEARCH_SYSTEM32   0x00000800
-#endif
-
-/* We use our own typedef here since some headers might lack these */
-typedef HMODULE (APIENTRY *LOADLIBRARYEX_FN)(LPCTSTR, HANDLE, DWORD);
-
-/* See function definitions in winbase.h */
-#ifdef UNICODE
-#  ifdef _WIN32_WCE
-#    define LOADLIBARYEX  L"LoadLibraryExW"
-#  else
-#    define LOADLIBARYEX  "LoadLibraryExW"
-#  endif
-#else
-#  define LOADLIBARYEX    "LoadLibraryExA"
-#endif
-
-
-/*
- * _Expat_LoadLibrary()
- *
- * This is used to dynamically load DLLs using the most secure method available
- * for the version of Windows that we are running on.
- *
- * Parameters:
- *
- * filename  [in] - The filename or full path of the DLL to load. If only the
- *                  filename is passed then the DLL will be loaded from the
- *                  Windows system directory.
- *
- * Returns the handle of the module on success; otherwise NULL.
- */
-HMODULE _Expat_LoadLibrary(LPCTSTR filename)
-{
-  HMODULE hModule = NULL;
-  LOADLIBRARYEX_FN pLoadLibraryEx = NULL;
-
-  /* Get a handle to kernel32 so we can access it's functions at runtime */
-  HMODULE hKernel32 = GetModuleHandle(TEXT("kernel32"));
-  if(!hKernel32)
-    return NULL;  /* LCOV_EXCL_LINE */
-
-  /* Attempt to find LoadLibraryEx() which is only available on Windows 2000
-     and above */
-  pLoadLibraryEx = (LOADLIBRARYEX_FN) GetProcAddress(hKernel32, LOADLIBARYEX);
-
-  /* Detect if there's already a path in the filename and load the library if
-     there is. Note: Both back slashes and forward slashes have been supported
-     since the earlier days of DOS at an API level although they are not
-     supported by command prompt */
-  if(_tcspbrk(filename, TEXT("\\/"))) {
-    /** !checksrc! disable BANNEDFUNC 1 **/
-    hModule = pLoadLibraryEx ?
-      pLoadLibraryEx(filename, NULL, LOAD_WITH_ALTERED_SEARCH_PATH) :
-      LoadLibrary(filename);
-  }
-  /* Detect if KB2533623 is installed, as LOAD_LIBARY_SEARCH_SYSTEM32 is only
-     supported on Windows Vista, Windows Server 2008, Windows 7 and Windows
-     Server 2008 R2 with this patch or natively on Windows 8 and above */
-  else if(pLoadLibraryEx && GetProcAddress(hKernel32, "AddDllDirectory")) {
-    /* Load the DLL from the Windows system directory */
-    hModule = pLoadLibraryEx(filename, NULL, LOAD_LIBRARY_SEARCH_SYSTEM32);
-  }
-  else {
-    /* Attempt to get the Windows system path */
-    UINT systemdirlen = GetSystemDirectory(NULL, 0);
-    if(systemdirlen) {
-      /* Allocate space for the full DLL path (Room for the null terminator
-         is included in systemdirlen) */
-      size_t filenamelen = _tcslen(filename);
-      TCHAR *path = malloc(sizeof(TCHAR) * (systemdirlen + 1 + filenamelen));
-      if(path && GetSystemDirectory(path, systemdirlen)) {
-        /* Calculate the full DLL path */
-        _tcscpy(path + _tcslen(path), TEXT("\\"));
-        _tcscpy(path + _tcslen(path), filename);
-
-        /* Load the DLL from the Windows system directory */
-        /** !checksrc! disable BANNEDFUNC 1 **/
-        hModule = pLoadLibraryEx ?
-          pLoadLibraryEx(path, NULL, LOAD_WITH_ALTERED_SEARCH_PATH) :
-          LoadLibrary(path);
-
-      }
-      free(path);
-    }
-  }
-
-  return hModule;
-}
-
-#else /* defined(_WIN32) */
-
-/* ISO C requires a translation unit to contain at least one declaration
-   [-Wempty-translation-unit] */
-typedef int _TRANSLATION_UNIT_LOAD_LIBRARY_C_NOT_EMTPY;
-
-#endif /* defined(_WIN32) */
diff --git a/contrib/expat/lib/nametab.h b/contrib/expat/lib/nametab.h
index 3681df348eeb..63485446b967 100644
--- a/contrib/expat/lib/nametab.h
+++ b/contrib/expat/lib/nametab.h
@@ -6,8 +6,8 @@
                         \___/_/\_\ .__/ \__,_|\__|
                                  |_| XML parser
 
-   Copyright (c) 1997-2000 Thai Open Source Software Center Ltd
-   Copyright (c) 2000-2017 Expat development team
+   Copyright (c) 2000 Clark Cooper <coopercc@users.sourceforge.net>
+   Copyright (c) 2017 Sebastian Pipping <sebastian@pipping.org>
    Licensed under the MIT license:
 
    Permission is  hereby granted,  free of charge,  to any  person obtaining
diff --git a/contrib/expat/lib/siphash.h b/contrib/expat/lib/siphash.h
index bfee65a332f1..e5406d7ee9eb 100644
--- a/contrib/expat/lib/siphash.h
+++ b/contrib/expat/lib/siphash.h
@@ -11,6 +11,9 @@
  * --------------------------------------------------------------------------
  * HISTORY:
  *
+ * 2020-10-03  (Sebastian Pipping)
+ *   - Drop support for Visual Studio 9.0/2008 and earlier
+ *
  * 2019-08-03  (Sebastian Pipping)
  *   - Mark part of sip24_valid as to be excluded from clang-format
  *   - Re-format code using clang-format 9
@@ -96,15 +99,7 @@
 #define SIPHASH_H
 
 #include <stddef.h> /* size_t */
-
-#if defined(_WIN32) && defined(_MSC_VER) && (_MSC_VER < 1600)
-/* For vs2003/7.1 up to vs2008/9.0; _MSC_VER 1600 is vs2010/10.0 */
-typedef unsigned __int8 uint8_t;
-typedef unsigned __int32 uint32_t;
-typedef unsigned __int64 uint64_t;
-#else
-#  include <stdint.h> /* uint64_t uint32_t uint8_t */
-#endif
+#include <stdint.h> /* uint64_t uint32_t uint8_t */
 
 /*
  * Workaround to not require a C++11 compiler for using ULL suffix
diff --git a/contrib/expat/lib/utf8tab.h b/contrib/expat/lib/utf8tab.h
index a22986acbb95..88efcf91cc16 100644
--- a/contrib/expat/lib/utf8tab.h
+++ b/contrib/expat/lib/utf8tab.h
@@ -7,7 +7,9 @@
                                  |_| XML parser
 
    Copyright (c) 1997-2000 Thai Open Source Software Center Ltd
-   Copyright (c) 2000-2017 Expat development team
+   Copyright (c) 2000      Clark Cooper <coopercc@users.sourceforge.net>
+   Copyright (c) 2002      Fred L. Drake, Jr. <fdrake@users.sourceforge.net>
+   Copyright (c) 2017      Sebastian Pipping <sebastian@pipping.org>
    Licensed under the MIT license:
 
    Permission is  hereby granted,  free of charge,  to any  person obtaining
diff --git a/contrib/expat/lib/xmlparse.c b/contrib/expat/lib/xmlparse.c
index 3aaf35b94b1d..b2f5fc6bee77 100644
--- a/contrib/expat/lib/xmlparse.c
+++ b/contrib/expat/lib/xmlparse.c
@@ -1,4 +1,4 @@
-/* f519f27c7c3b79fee55aeb8b1e53b7384b079d9118bf3a62eb3a60986a6742f2 (2.2.9+)
+/* 9ca2a2fedc35bcb13ba9a134ba5e173020bc2ff5f5a311abf742cec7da1ff26a (2.4.3+)
                             __  __            _
                          ___\ \/ /_ __   __ _| |_
                         / _ \\  /| '_ \ / _` | __|
@@ -7,7 +7,32 @@
                                  |_| XML parser
 
    Copyright (c) 1997-2000 Thai Open Source Software Center Ltd
-   Copyright (c) 2000-2017 Expat development team
+   Copyright (c) 2000      Clark Cooper <coopercc@users.sourceforge.net>
+   Copyright (c) 2000-2006 Fred L. Drake, Jr. <fdrake@users.sourceforge.net>
+   Copyright (c) 2001-2002 Greg Stein <gstein@users.sourceforge.net>
+   Copyright (c) 2002-2016 Karl Waclawek <karl@waclawek.net>
+   Copyright (c) 2005-2009 Steven Solie <ssolie@users.sourceforge.net>
+   Copyright (c) 2016      Eric Rahm <erahm@mozilla.com>
+   Copyright (c) 2016-2022 Sebastian Pipping <sebastian@pipping.org>
+   Copyright (c) 2016      Gaurav <g.gupta@samsung.com>
+   Copyright (c) 2016      Thomas Beutlich <tc@tbeu.de>
+   Copyright (c) 2016      Gustavo Grieco <gustavo.grieco@imag.fr>
+   Copyright (c) 2016      Pascal Cuoq <cuoq@trust-in-soft.com>
+   Copyright (c) 2016      Ed Schouten <ed@nuxi.nl>
+   Copyright (c) 2017-2018 Rhodri James <rhodri@wildebeest.org.uk>
+   Copyright (c) 2017      Václav Slavík <vaclav@slavik.io>
+   Copyright (c) 2017      Viktor Szakats <commit@vsz.me>
+   Copyright (c) 2017      Chanho Park <chanho61.park@samsung.com>
+   Copyright (c) 2017      Rolf Eike Beer <eike@sf-mail.de>
+   Copyright (c) 2017      Hans Wennborg <hans@chromium.org>
+   Copyright (c) 2018      Anton Maklakov <antmak.pub@gmail.com>
+   Copyright (c) 2018      Benjamin Peterson <benjamin@python.org>
+   Copyright (c) 2018      Marco Maggi <marco.maggi-ipsu@poste.it>
+   Copyright (c) 2018      Mariusz Zaborski <oshogbo@vexillium.org>
+   Copyright (c) 2019      David Loffredo <loffredo@steptools.com>
+   Copyright (c) 2019-2020 Ben Wagner <bungeman@chromium.org>
+   Copyright (c) 2019      Vadim Zeitlin <vadim@zeitlins.org>
+   Copyright (c) 2021      Dong-hee Na <donghee.na@python.org>
    Licensed under the MIT license:
 
    Permission is  hereby granted,  free of charge,  to any  person obtaining
@@ -30,6 +55,10 @@
    USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
 
+#define XML_BUILDING_EXPAT 1
+
+#include <expat_config.h>
+
 #if ! defined(_GNU_SOURCE)
 #  define _GNU_SOURCE 1 /* syscall prototype */
 #endif
@@ -47,6 +76,8 @@
 #include <limits.h> /* UINT_MAX */
 #include <stdio.h>  /* fprintf */
 #include <stdlib.h> /* getenv, rand_s */
+#include <stdint.h> /* uintptr_t */
+#include <math.h>   /* isnan */
 
 #ifdef _WIN32
 #  define getpid GetCurrentProcessId
@@ -58,13 +89,9 @@
 #  include <errno.h>
 #endif
 
-#define XML_BUILDING_EXPAT 1
-
 #ifdef _WIN32
 #  include "winconfig.h"
-#elif defined(HAVE_EXPAT_CONFIG_H)
-#  include <expat_config.h>
-#endif /* ndef _WIN32 */
+#endif
 
 #include "ascii.h"
 #include "expat.h"
@@ -99,14 +126,14 @@
     enabled.  For end user security, that is probably not what you want. \
     \
     Your options include: \
-      * Linux + glibc >=2.25 (getrandom): HAVE_GETRANDOM, \
-      * Linux + glibc <2.25 (syscall SYS_getrandom): HAVE_SYSCALL_GETRANDOM, \
+      * Linux >=3.17 + glibc >=2.25 (getrandom): HAVE_GETRANDOM, \
+      * Linux >=3.17 + glibc (including <2.25) (syscall SYS_getrandom): HAVE_SYSCALL_GETRANDOM, \
       * BSD / macOS >=10.7 (arc4random_buf): HAVE_ARC4RANDOM_BUF, \
-      * BSD / macOS <10.7 (arc4random): HAVE_ARC4RANDOM, \
+      * BSD / macOS (including <10.7) (arc4random): HAVE_ARC4RANDOM, \
       * libbsd (arc4random_buf): HAVE_ARC4RANDOM_BUF + HAVE_LIBBSD, \
       * libbsd (arc4random): HAVE_ARC4RANDOM + HAVE_LIBBSD, \
-      * Linux / BSD / macOS (/dev/urandom): XML_DEV_URANDOM \
-      * Windows (rand_s): _WIN32. \
+      * Linux (including <3.17) / BSD / macOS (including <10.7) (/dev/urandom): XML_DEV_URANDOM, \
+      * Windows >=Vista (rand_s): _WIN32. \
     \
     If insist on not using any of these, bypass this error by defining \
     XML_POOR_ENTROPY; you have been warned. \
@@ -121,9 +148,7 @@
 #  define XmlGetInternalEncoding XmlGetUtf16InternalEncoding
 #  define XmlGetInternalEncodingNS XmlGetUtf16InternalEncodingNS
 #  define XmlEncode XmlUtf16Encode
-/* Using pointer subtraction to convert to integer type. */
-#  define MUST_CONVERT(enc, s)                                                 \
-    (! (enc)->isUtf16 || (((char *)(s) - (char *)NULL) & 1))
+#  define MUST_CONVERT(enc, s) (! (enc)->isUtf16 || (((uintptr_t)(s)) & 1))
 typedef unsigned short ICHAR;
 #else
 #  define XML_ENCODE_MAX XML_UTF8_ENCODE_MAX
@@ -373,6 +398,31 @@ typedef struct open_internal_entity {
   XML_Bool betweenDecl; /* WFC: PE Between Declarations */
 } OPEN_INTERNAL_ENTITY;
 
+enum XML_Account {
+  XML_ACCOUNT_DIRECT,           /* bytes directly passed to the Expat parser */
+  XML_ACCOUNT_ENTITY_EXPANSION, /* intermediate bytes produced during entity
+                                   expansion */
+  XML_ACCOUNT_NONE              /* i.e. do not account, was accounted already */
+};
+
+#ifdef XML_DTD
+typedef unsigned long long XmlBigCount;
+typedef struct accounting {
+  XmlBigCount countBytesDirect;
+  XmlBigCount countBytesIndirect;
+  int debugLevel;
+  float maximumAmplificationFactor; // >=1.0
+  unsigned long long activationThresholdBytes;
+} ACCOUNTING;
+
+typedef struct entity_stats {
+  unsigned int countEverOpened;
+  unsigned int currentDepth;
+  unsigned int maximumDepthSeen;
+  int debugLevel;
+} ENTITY_STATS;
+#endif /* XML_DTD */
+
 typedef enum XML_Error PTRCALL Processor(XML_Parser parser, const char *start,
                                          const char *end, const char **endPtr);
 
@@ -403,16 +453,18 @@ static enum XML_Error initializeEncoding(XML_Parser parser);
 static enum XML_Error doProlog(XML_Parser parser, const ENCODING *enc,
                                const char *s, const char *end, int tok,
                                const char *next, const char **nextPtr,
-                               XML_Bool haveMore, XML_Bool allowClosingDoctype);
+                               XML_Bool haveMore, XML_Bool allowClosingDoctype,
+                               enum XML_Account account);
 static enum XML_Error processInternalEntity(XML_Parser parser, ENTITY *entity,
                                             XML_Bool betweenDecl);
 static enum XML_Error doContent(XML_Parser parser, int startTagLevel,
                                 const ENCODING *enc, const char *start,
                                 const char *end, const char **endPtr,
-                                XML_Bool haveMore);
+                                XML_Bool haveMore, enum XML_Account account);
 static enum XML_Error doCdataSection(XML_Parser parser, const ENCODING *,
                                      const char **startPtr, const char *end,
-                                     const char **nextPtr, XML_Bool haveMore);
+                                     const char **nextPtr, XML_Bool haveMore,
+                                     enum XML_Account account);
 #ifdef XML_DTD
 static enum XML_Error doIgnoreSection(XML_Parser parser, const ENCODING *,
                                       const char **startPtr, const char *end,
@@ -422,7 +474,8 @@ static enum XML_Error doIgnoreSection(XML_Parser parser, const ENCODING *,
 static void freeBindings(XML_Parser parser, BINDING *bindings);
 static enum XML_Error storeAtts(XML_Parser parser, const ENCODING *,
                                 const char *s, TAG_NAME *tagNamePtr,
-                                BINDING **bindingsPtr);
+                                BINDING **bindingsPtr,
+                                enum XML_Account account);
 static enum XML_Error addBinding(XML_Parser parser, PREFIX *prefix,
                                  const ATTRIBUTE_ID *attId, const XML_Char *uri,
                                  BINDING **bindingsPtr);
@@ -431,15 +484,18 @@ static int defineAttribute(ELEMENT_TYPE *type, ATTRIBUTE_ID *, XML_Bool isCdata,
                            XML_Parser parser);
 static enum XML_Error storeAttributeValue(XML_Parser parser, const ENCODING *,
                                           XML_Bool isCdata, const char *,
-                                          const char *, STRING_POOL *);
+                                          const char *, STRING_POOL *,
+                                          enum XML_Account account);
 static enum XML_Error appendAttributeValue(XML_Parser parser, const ENCODING *,
                                            XML_Bool isCdata, const char *,
-                                           const char *, STRING_POOL *);
+                                           const char *, STRING_POOL *,
+                                           enum XML_Account account);
 static ATTRIBUTE_ID *getAttributeId(XML_Parser parser, const ENCODING *enc,
                                     const char *start, const char *end);
 static int setElementTypePrefix(XML_Parser parser, ELEMENT_TYPE *);
 static enum XML_Error storeEntityValue(XML_Parser parser, const ENCODING *enc,
-                                       const char *start, const char *end);
+                                       const char *start, const char *end,
+                                       enum XML_Account account);
 static int reportProcessingInstruction(XML_Parser parser, const ENCODING *enc,
                                        const char *start, const char *end);
 static int reportComment(XML_Parser parser, const ENCODING *enc,
@@ -503,6 +559,34 @@ static XML_Parser parserCreate(const XML_Char *encodingName,
 
 static void parserInit(XML_Parser parser, const XML_Char *encodingName);
 
+#ifdef XML_DTD
+static float accountingGetCurrentAmplification(XML_Parser rootParser);
+static void accountingReportStats(XML_Parser originParser, const char *epilog);
+static void accountingOnAbort(XML_Parser originParser);
+static void accountingReportDiff(XML_Parser rootParser,
+                                 unsigned int levelsAwayFromRootParser,
+                                 const char *before, const char *after,
+                                 ptrdiff_t bytesMore, int source_line,
+                                 enum XML_Account account);
+static XML_Bool accountingDiffTolerated(XML_Parser originParser, int tok,
+                                        const char *before, const char *after,
+                                        int source_line,
+                                        enum XML_Account account);
+
+static void entityTrackingReportStats(XML_Parser parser, ENTITY *entity,
+                                      const char *action, int sourceLine);
+static void entityTrackingOnOpen(XML_Parser parser, ENTITY *entity,
+                                 int sourceLine);
+static void entityTrackingOnClose(XML_Parser parser, ENTITY *entity,
+                                  int sourceLine);
+
+static XML_Parser getRootParserOf(XML_Parser parser,
+                                  unsigned int *outLevelDiff);
+#endif /* XML_DTD */
+
+static unsigned long getDebugLevel(const char *variableName,
+                                   unsigned long defaultDebugLevel);
+
 #define poolStart(pool) ((pool)->start)
 #define poolEnd(pool) ((pool)->ptr)
 #define poolLength(pool) ((pool)->ptr - (pool)->start)
@@ -616,6 +700,10 @@ struct XML_ParserStruct {
   enum XML_ParamEntityParsing m_paramEntityParsing;
 #endif
   unsigned long m_hash_secret_salt;
+#ifdef XML_DTD
+  ACCOUNTING m_accounting;
+  ENTITY_STATS m_entity_stats;
+#endif
 };
 
 #define MALLOC(parser, s) (parser->m_mem.malloc_fcn((s)))
@@ -736,6 +824,15 @@ writeRandomBytes_arc4random(void *target, size_t count) {
 
 #ifdef _WIN32
 
+/* Provide declaration of rand_s() for MinGW-32 (not 64, which has it),
+   as it didn't declare it in its header prior to version 5.3.0 of its
+   runtime package (mingwrt, containing stdlib.h).  The upstream fix
+   was introduced at https://osdn.net/projects/mingw/ticket/39658 . */
+#  if defined(__MINGW32__) && defined(__MINGW32_VERSION)                       \
+      && __MINGW32_VERSION < 5003000L && ! defined(__MINGW64_VERSION_MAJOR)
+__declspec(dllimport) int rand_s(unsigned int *);
+#  endif
+
 /* Obtain entropy on Windows using the rand_s() function which
  * generates cryptographically secure random numbers.  Internally it
  * uses RtlGenRandom API which is present in Windows XP and later.
@@ -791,9 +888,8 @@ gather_time_entropy(void) {
 
 static unsigned long
 ENTROPY_DEBUG(const char *label, unsigned long entropy) {
-  const char *const EXPAT_ENTROPY_DEBUG = getenv("EXPAT_ENTROPY_DEBUG");
-  if (EXPAT_ENTROPY_DEBUG && ! strcmp(EXPAT_ENTROPY_DEBUG, "1")) {
-    fprintf(stderr, "Entropy: %s --> 0x%0*lx (%lu bytes)\n", label,
+  if (getDebugLevel("EXPAT_ENTROPY_DEBUG", 0) >= 1u) {
+    fprintf(stderr, "expat: Entropy: %s --> 0x%0*lx (%lu bytes)\n", label,
             (int)sizeof(entropy) * 2, entropy, (unsigned long)sizeof(entropy));
   }
   return entropy;
@@ -1055,6 +1151,18 @@ parserInit(XML_Parser parser, const XML_Char *encodingName) {
   parser->m_paramEntityParsing = XML_PARAM_ENTITY_PARSING_NEVER;
 #endif
   parser->m_hash_secret_salt = 0;
+
+#ifdef XML_DTD
+  memset(&parser->m_accounting, 0, sizeof(ACCOUNTING));
+  parser->m_accounting.debugLevel = getDebugLevel("EXPAT_ACCOUNTING_DEBUG", 0u);
+  parser->m_accounting.maximumAmplificationFactor
+      = EXPAT_BILLION_LAUGHS_ATTACK_PROTECTION_MAXIMUM_AMPLIFICATION_DEFAULT;
+  parser->m_accounting.activationThresholdBytes
+      = EXPAT_BILLION_LAUGHS_ATTACK_PROTECTION_ACTIVATION_THRESHOLD_DEFAULT;
+
+  memset(&parser->m_entity_stats, 0, sizeof(ENTITY_STATS));
+  parser->m_entity_stats.debugLevel = getDebugLevel("EXPAT_ENTITY_DEBUG", 0u);
+#endif
 }
 
 /* moves list of bindings to m_freeBindingList */
@@ -1401,6 +1509,7 @@ XML_UseForeignDTD(XML_Parser parser, XML_Bool useDTD) {
   parser->m_useForeignDTD = useDTD;
   return XML_ERROR_NONE;
 #else
+  UNUSED_P(useDTD);
   return XML_ERROR_FEATURE_REQUIRES_XML_DTD;
 #endif
 }
@@ -1782,7 +1891,7 @@ XML_Parse(XML_Parser parser, const char *s, int len, int isFinal) {
     int nLeftOver;
     enum XML_Status result;
     /* Detect overflow (a+b > MAX <==> b > MAX-a) */
-    if (len > ((XML_Size)-1) / 2 - parser->m_parseEndByteIndex) {
+    if ((XML_Size)len > ((XML_Size)-1) / 2 - parser->m_parseEndByteIndex) {
       parser->m_errorCode = XML_ERROR_NO_MEMORY;
       parser->m_eventPtr = parser->m_eventEndPtr = NULL;
       parser->m_processor = errorProcessor;
@@ -1874,6 +1983,12 @@ XML_ParseBuffer(XML_Parser parser, int len, int isFinal) {
     parser->m_errorCode = XML_ERROR_FINISHED;
     return XML_STATUS_ERROR;
   case XML_INITIALIZED:
+    /* Has someone called XML_GetBuffer successfully before? */
+    if (! parser->m_bufferPtr) {
+      parser->m_errorCode = XML_ERROR_NO_BUFFER;
+      return XML_STATUS_ERROR;
+    }
+
     if (parser->m_parentParser == NULL && ! startParsing(parser)) {
       parser->m_errorCode = XML_ERROR_NO_MEMORY;
       return XML_STATUS_ERROR;
@@ -2157,7 +2272,7 @@ XML_GetInputContext(XML_Parser parser, int *offset, int *size) {
   (void)offset;
   (void)size;
 #endif /* defined XML_CONTEXT_BYTES */
-  return (char *)0;
+  return (const char *)0;
 }
 
 XML_Size XMLCALL
@@ -2318,6 +2433,14 @@ XML_ErrorString(enum XML_Error code) {
   /* Added in 2.2.5. */
   case XML_ERROR_INVALID_ARGUMENT: /* Constant added in 2.2.1, already */
     return XML_L("invalid argument");
+    /* Added in 2.3.0. */
+  case XML_ERROR_NO_BUFFER:
+    return XML_L(
+        "a successful prior call to function XML_GetBuffer is required");
+  /* Added in 2.4.0. */
+  case XML_ERROR_AMPLIFICATION_LIMIT_BREACH:
+    return XML_L(
+        "limit on input amplification factor (from DTD and entities) breached");
   }
   return NULL;
 }
@@ -2354,41 +2477,75 @@ XML_ExpatVersionInfo(void) {
 
 const XML_Feature *XMLCALL
 XML_GetFeatureList(void) {
-  static const XML_Feature features[]
-      = {{XML_FEATURE_SIZEOF_XML_CHAR, XML_L("sizeof(XML_Char)"),
-          sizeof(XML_Char)},
-         {XML_FEATURE_SIZEOF_XML_LCHAR, XML_L("sizeof(XML_LChar)"),
-          sizeof(XML_LChar)},
+  static const XML_Feature features[] = {
+      {XML_FEATURE_SIZEOF_XML_CHAR, XML_L("sizeof(XML_Char)"),
+       sizeof(XML_Char)},
+      {XML_FEATURE_SIZEOF_XML_LCHAR, XML_L("sizeof(XML_LChar)"),
+       sizeof(XML_LChar)},
 #ifdef XML_UNICODE
-         {XML_FEATURE_UNICODE, XML_L("XML_UNICODE"), 0},
+      {XML_FEATURE_UNICODE, XML_L("XML_UNICODE"), 0},
 #endif
 #ifdef XML_UNICODE_WCHAR_T
-         {XML_FEATURE_UNICODE_WCHAR_T, XML_L("XML_UNICODE_WCHAR_T"), 0},
+      {XML_FEATURE_UNICODE_WCHAR_T, XML_L("XML_UNICODE_WCHAR_T"), 0},
 #endif
 #ifdef XML_DTD
-         {XML_FEATURE_DTD, XML_L("XML_DTD"), 0},
+      {XML_FEATURE_DTD, XML_L("XML_DTD"), 0},
 #endif
 #ifdef XML_CONTEXT_BYTES
-         {XML_FEATURE_CONTEXT_BYTES, XML_L("XML_CONTEXT_BYTES"),
-          XML_CONTEXT_BYTES},
+      {XML_FEATURE_CONTEXT_BYTES, XML_L("XML_CONTEXT_BYTES"),
+       XML_CONTEXT_BYTES},
 #endif
 #ifdef XML_MIN_SIZE
-         {XML_FEATURE_MIN_SIZE, XML_L("XML_MIN_SIZE"), 0},
+      {XML_FEATURE_MIN_SIZE, XML_L("XML_MIN_SIZE"), 0},
 #endif
 #ifdef XML_NS
-         {XML_FEATURE_NS, XML_L("XML_NS"), 0},
+      {XML_FEATURE_NS, XML_L("XML_NS"), 0},
 #endif
 #ifdef XML_LARGE_SIZE
-         {XML_FEATURE_LARGE_SIZE, XML_L("XML_LARGE_SIZE"), 0},
+      {XML_FEATURE_LARGE_SIZE, XML_L("XML_LARGE_SIZE"), 0},
 #endif
 #ifdef XML_ATTR_INFO
-         {XML_FEATURE_ATTR_INFO, XML_L("XML_ATTR_INFO"), 0},
+      {XML_FEATURE_ATTR_INFO, XML_L("XML_ATTR_INFO"), 0},
 #endif
-         {XML_FEATURE_END, NULL, 0}};
+#ifdef XML_DTD
+      /* Added in Expat 2.4.0. */
+      {XML_FEATURE_BILLION_LAUGHS_ATTACK_PROTECTION_MAXIMUM_AMPLIFICATION_DEFAULT,
+       XML_L("XML_BLAP_MAX_AMP"),
+       (long int)
+           EXPAT_BILLION_LAUGHS_ATTACK_PROTECTION_MAXIMUM_AMPLIFICATION_DEFAULT},
+      {XML_FEATURE_BILLION_LAUGHS_ATTACK_PROTECTION_ACTIVATION_THRESHOLD_DEFAULT,
+       XML_L("XML_BLAP_ACT_THRES"),
+       EXPAT_BILLION_LAUGHS_ATTACK_PROTECTION_ACTIVATION_THRESHOLD_DEFAULT},
+#endif
+      {XML_FEATURE_END, NULL, 0}};
 
   return features;
 }
 
+#ifdef XML_DTD
+XML_Bool XMLCALL
+XML_SetBillionLaughsAttackProtectionMaximumAmplification(
+    XML_Parser parser, float maximumAmplificationFactor) {
+  if ((parser == NULL) || (parser->m_parentParser != NULL)
+      || isnan(maximumAmplificationFactor)
+      || (maximumAmplificationFactor < 1.0f)) {
+    return XML_FALSE;
+  }
+  parser->m_accounting.maximumAmplificationFactor = maximumAmplificationFactor;
+  return XML_TRUE;
+}
+
+XML_Bool XMLCALL
+XML_SetBillionLaughsAttackProtectionActivationThreshold(
+    XML_Parser parser, unsigned long long activationThresholdBytes) {
+  if ((parser == NULL) || (parser->m_parentParser != NULL)) {
+    return XML_FALSE;
+  }
+  parser->m_accounting.activationThresholdBytes = activationThresholdBytes;
+  return XML_TRUE;
+}
+#endif /* XML_DTD */
+
 /* Initially tag->rawName always points into the parse buffer;
    for those TAG instances opened while the current parse buffer was
    processed, and not yet closed, we need to store tag->rawName in a more
@@ -2441,9 +2598,9 @@ storeRawNames(XML_Parser parser) {
 static enum XML_Error PTRCALL
 contentProcessor(XML_Parser parser, const char *start, const char *end,
                  const char **endPtr) {
-  enum XML_Error result
-      = doContent(parser, 0, parser->m_encoding, start, end, endPtr,
-                  (XML_Bool)! parser->m_parsingStatus.finalBuffer);
+  enum XML_Error result = doContent(
+      parser, 0, parser->m_encoding, start, end, endPtr,
+      (XML_Bool)! parser->m_parsingStatus.finalBuffer, XML_ACCOUNT_DIRECT);
   if (result == XML_ERROR_NONE) {
     if (! storeRawNames(parser))
       return XML_ERROR_NO_MEMORY;
@@ -2468,6 +2625,14 @@ externalEntityInitProcessor2(XML_Parser parser, const char *start,
   int tok = XmlContentTok(parser->m_encoding, start, end, &next);
   switch (tok) {
   case XML_TOK_BOM:
+#ifdef XML_DTD
+    if (! accountingDiffTolerated(parser, tok, start, next, __LINE__,
+                                  XML_ACCOUNT_DIRECT)) {
+      accountingOnAbort(parser);
+      return XML_ERROR_AMPLIFICATION_LIMIT_BREACH;
+    }
+#endif /* XML_DTD */
+
     /* If we are at the end of the buffer, this would cause the next stage,
        i.e. externalEntityInitProcessor3, to pass control directly to
        doContent (by detecting XML_TOK_NONE) without processing any xml text
@@ -2505,6 +2670,10 @@ externalEntityInitProcessor3(XML_Parser parser, const char *start,
   const char *next = start; /* XmlContentTok doesn't always set the last arg */
   parser->m_eventPtr = start;
   tok = XmlContentTok(parser->m_encoding, start, end, &next);
+  /* Note: These bytes are accounted later in:
+           - processXmlDecl
+           - externalEntityContentProcessor
+  */
   parser->m_eventEndPtr = next;
 
   switch (tok) {
@@ -2546,7 +2715,8 @@ externalEntityContentProcessor(XML_Parser parser, const char *start,
                                const char *end, const char **endPtr) {
   enum XML_Error result
       = doContent(parser, 1, parser->m_encoding, start, end, endPtr,
-                  (XML_Bool)! parser->m_parsingStatus.finalBuffer);
+                  (XML_Bool)! parser->m_parsingStatus.finalBuffer,
+                  XML_ACCOUNT_ENTITY_EXPANSION);
   if (result == XML_ERROR_NONE) {
     if (! storeRawNames(parser))
       return XML_ERROR_NO_MEMORY;
@@ -2557,7 +2727,7 @@ externalEntityContentProcessor(XML_Parser parser, const char *start,
 static enum XML_Error
 doContent(XML_Parser parser, int startTagLevel, const ENCODING *enc,
           const char *s, const char *end, const char **nextPtr,
-          XML_Bool haveMore) {
+          XML_Bool haveMore, enum XML_Account account) {
   /* save one level of indirection */
   DTD *const dtd = parser->m_dtd;
 
@@ -2575,6 +2745,17 @@ doContent(XML_Parser parser, int startTagLevel, const ENCODING *enc,
   for (;;) {
     const char *next = s; /* XmlContentTok doesn't always set the last arg */
     int tok = XmlContentTok(enc, s, end, &next);
+#ifdef XML_DTD
+    const char *accountAfter
+        = ((tok == XML_TOK_TRAILING_RSQB) || (tok == XML_TOK_TRAILING_CR))
+              ? (haveMore ? s /* i.e. 0 bytes */ : end)
+              : next;
+    if (! accountingDiffTolerated(parser, tok, s, accountAfter, __LINE__,
+                                  account)) {
+      accountingOnAbort(parser);
+      return XML_ERROR_AMPLIFICATION_LIMIT_BREACH;
+    }
+#endif
     *eventEndPP = next;
     switch (tok) {
     case XML_TOK_TRAILING_CR:
@@ -2630,6 +2811,14 @@ doContent(XML_Parser parser, int startTagLevel, const ENCODING *enc,
       XML_Char ch = (XML_Char)XmlPredefinedEntityName(
           enc, s + enc->minBytesPerChar, next - enc->minBytesPerChar);
       if (ch) {
+#ifdef XML_DTD
+        /* NOTE: We are replacing 4-6 characters original input for 1 character
+         *       so there is no amplification and hence recording without
+         *       protection. */
+        accountingDiffTolerated(parser, tok, (char *)&ch,
+                                ((char *)&ch) + sizeof(XML_Char), __LINE__,
+                                XML_ACCOUNT_ENTITY_EXPANSION);
+#endif /* XML_DTD */
         if (parser->m_characterDataHandler)
           parser->m_characterDataHandler(parser->m_handlerArg, &ch, 1);
         else if (parser->m_defaultHandler)
@@ -2748,7 +2937,8 @@ doContent(XML_Parser parser, int startTagLevel, const ENCODING *enc,
       }
       tag->name.str = (XML_Char *)tag->buf;
       *toPtr = XML_T('\0');
-      result = storeAtts(parser, enc, s, &(tag->name), &(tag->bindings));
+      result
+          = storeAtts(parser, enc, s, &(tag->name), &(tag->bindings), account);
       if (result)
         return result;
       if (parser->m_startElementHandler)
@@ -2772,7 +2962,8 @@ doContent(XML_Parser parser, int startTagLevel, const ENCODING *enc,
       if (! name.str)
         return XML_ERROR_NO_MEMORY;
       poolFinish(&parser->m_tempPool);
-      result = storeAtts(parser, enc, s, &name, &bindings);
+      result = storeAtts(parser, enc, s, &name, &bindings,
+                         XML_ACCOUNT_NONE /* token spans whole start tag */);
       if (result != XML_ERROR_NONE) {
         freeBindings(parser, bindings);
         return result;
@@ -2907,7 +3098,8 @@ doContent(XML_Parser parser, int startTagLevel, const ENCODING *enc,
       /* END disabled code */
       else if (parser->m_defaultHandler)
         reportDefault(parser, enc, s, next);
-      result = doCdataSection(parser, enc, &next, end, nextPtr, haveMore);
+      result
+          = doCdataSection(parser, enc, &next, end, nextPtr, haveMore, account);
       if (result != XML_ERROR_NONE)
         return result;
       else if (! next) {
@@ -3036,7 +3228,8 @@ freeBindings(XML_Parser parser, BINDING *bindings) {
 */
 static enum XML_Error
 storeAtts(XML_Parser parser, const ENCODING *enc, const char *attStr,
-          TAG_NAME *tagNamePtr, BINDING **bindingsPtr) {
+          TAG_NAME *tagNamePtr, BINDING **bindingsPtr,
+          enum XML_Account account) {
   DTD *const dtd = parser->m_dtd; /* save one level of indirection */
   ELEMENT_TYPE *elementType;
   int nDefaultAtts;
@@ -3068,13 +3261,38 @@ storeAtts(XML_Parser parser, const ENCODING *enc, const char *attStr,
 
   /* get the attributes from the tokenizer */
   n = XmlGetAttributes(enc, attStr, parser->m_attsSize, parser->m_atts);
+
+  /* Detect and prevent integer overflow */
+  if (n > INT_MAX - nDefaultAtts) {
+    return XML_ERROR_NO_MEMORY;
+  }
+
   if (n + nDefaultAtts > parser->m_attsSize) {
     int oldAttsSize = parser->m_attsSize;
     ATTRIBUTE *temp;
 #ifdef XML_ATTR_INFO
     XML_AttrInfo *temp2;
 #endif
+
+    /* Detect and prevent integer overflow */
+    if ((nDefaultAtts > INT_MAX - INIT_ATTS_SIZE)
+        || (n > INT_MAX - (nDefaultAtts + INIT_ATTS_SIZE))) {
+      return XML_ERROR_NO_MEMORY;
+    }
+
     parser->m_attsSize = n + nDefaultAtts + INIT_ATTS_SIZE;
+
+    /* Detect and prevent integer overflow.
+     * The preprocessor guard addresses the "always false" warning
+     * from -Wtype-limits on platforms where
+     * sizeof(unsigned int) < sizeof(size_t), e.g. on x86_64. */
+#if UINT_MAX >= SIZE_MAX
+    if ((unsigned)parser->m_attsSize > (size_t)(-1) / sizeof(ATTRIBUTE)) {
+      parser->m_attsSize = oldAttsSize;
+      return XML_ERROR_NO_MEMORY;
+    }
+#endif
+
     temp = (ATTRIBUTE *)REALLOC(parser, (void *)parser->m_atts,
                                 parser->m_attsSize * sizeof(ATTRIBUTE));
     if (temp == NULL) {
@@ -3083,6 +3301,17 @@ storeAtts(XML_Parser parser, const ENCODING *enc, const char *attStr,
     }
     parser->m_atts = temp;
 #ifdef XML_ATTR_INFO
+    /* Detect and prevent integer overflow.
+     * The preprocessor guard addresses the "always false" warning
+     * from -Wtype-limits on platforms where
+     * sizeof(unsigned int) < sizeof(size_t), e.g. on x86_64. */
+#  if UINT_MAX >= SIZE_MAX
+    if ((unsigned)parser->m_attsSize > (size_t)(-1) / sizeof(XML_AttrInfo)) {
+      parser->m_attsSize = oldAttsSize;
+      return XML_ERROR_NO_MEMORY;
+    }
+#  endif
+
     temp2 = (XML_AttrInfo *)REALLOC(parser, (void *)parser->m_attInfo,
                                     parser->m_attsSize * sizeof(XML_AttrInfo));
     if (temp2 == NULL) {
@@ -3146,7 +3375,7 @@ storeAtts(XML_Parser parser, const ENCODING *enc, const char *attStr,
       /* normalize the attribute value */
       result = storeAttributeValue(
           parser, enc, isCdata, parser->m_atts[i].valuePtr,
-          parser->m_atts[i].valueEnd, &parser->m_tempPool);
+          parser->m_atts[i].valueEnd, &parser->m_tempPool, account);
       if (result)
         return result;
       appAtts[attIndex] = poolStart(&parser->m_tempPool);
@@ -3221,7 +3450,13 @@ storeAtts(XML_Parser parser, const ENCODING *enc, const char *attStr,
   if (nPrefixes) {
     int j; /* hash table index */
     unsigned long version = parser->m_nsAttsVersion;
-    int nsAttsSize = (int)1 << parser->m_nsAttsPower;
+
+    /* Detect and prevent invalid shift */
+    if (parser->m_nsAttsPower >= sizeof(unsigned int) * 8 /* bits per byte */) {
+      return XML_ERROR_NO_MEMORY;
+    }
+
+    unsigned int nsAttsSize = 1u << parser->m_nsAttsPower;
     unsigned char oldNsAttsPower = parser->m_nsAttsPower;
     /* size of hash table must be at least 2 * (# of prefixed attributes) */
     if ((nPrefixes << 1)
@@ -3232,7 +3467,28 @@ storeAtts(XML_Parser parser, const ENCODING *enc, const char *attStr,
         ;
       if (parser->m_nsAttsPower < 3)
         parser->m_nsAttsPower = 3;
-      nsAttsSize = (int)1 << parser->m_nsAttsPower;
+
+      /* Detect and prevent invalid shift */
+      if (parser->m_nsAttsPower >= sizeof(nsAttsSize) * 8 /* bits per byte */) {
+        /* Restore actual size of memory in m_nsAtts */
+        parser->m_nsAttsPower = oldNsAttsPower;
+        return XML_ERROR_NO_MEMORY;
+      }
+
+      nsAttsSize = 1u << parser->m_nsAttsPower;
+
+      /* Detect and prevent integer overflow.
+       * The preprocessor guard addresses the "always false" warning
+       * from -Wtype-limits on platforms where
+       * sizeof(unsigned int) < sizeof(size_t), e.g. on x86_64. */
+#if UINT_MAX >= SIZE_MAX
+      if (nsAttsSize > (size_t)(-1) / sizeof(NS_ATT)) {
+        /* Restore actual size of memory in m_nsAtts */
+        parser->m_nsAttsPower = oldNsAttsPower;
+        return XML_ERROR_NO_MEMORY;
+      }
+#endif
+
       temp = (NS_ATT *)REALLOC(parser, parser->m_nsAtts,
                                nsAttsSize * sizeof(NS_ATT));
       if (! temp) {
@@ -3390,9 +3646,31 @@ storeAtts(XML_Parser parser, const ENCODING *enc, const char *attStr,
   tagNamePtr->prefixLen = prefixLen;
   for (i = 0; localPart[i++];)
     ; /* i includes null terminator */
+
+  /* Detect and prevent integer overflow */
+  if (binding->uriLen > INT_MAX - prefixLen
+      || i > INT_MAX - (binding->uriLen + prefixLen)) {
+    return XML_ERROR_NO_MEMORY;
+  }
+
   n = i + binding->uriLen + prefixLen;
   if (n > binding->uriAlloc) {
     TAG *p;
+
+    /* Detect and prevent integer overflow */
+    if (n > INT_MAX - EXPAND_SPARE) {
+      return XML_ERROR_NO_MEMORY;
+    }
+    /* Detect and prevent integer overflow.
+     * The preprocessor guard addresses the "always false" warning
+     * from -Wtype-limits on platforms where
+     * sizeof(unsigned int) < sizeof(size_t), e.g. on x86_64. */
+#if UINT_MAX >= SIZE_MAX
+    if ((unsigned)(n + EXPAND_SPARE) > (size_t)(-1) / sizeof(XML_Char)) {
+      return XML_ERROR_NO_MEMORY;
+    }
+#endif
+
     uri = (XML_Char *)MALLOC(parser, (n + EXPAND_SPARE) * sizeof(XML_Char));
     if (! uri)
       return XML_ERROR_NO_MEMORY;
@@ -3488,6 +3766,21 @@ addBinding(XML_Parser parser, PREFIX *prefix, const ATTRIBUTE_ID *attId,
   if (parser->m_freeBindingList) {
     b = parser->m_freeBindingList;
     if (len > b->uriAlloc) {
+      /* Detect and prevent integer overflow */
+      if (len > INT_MAX - EXPAND_SPARE) {
+        return XML_ERROR_NO_MEMORY;
+      }
+
+      /* Detect and prevent integer overflow.
+       * The preprocessor guard addresses the "always false" warning
+       * from -Wtype-limits on platforms where
+       * sizeof(unsigned int) < sizeof(size_t), e.g. on x86_64. */
+#if UINT_MAX >= SIZE_MAX
+      if ((unsigned)(len + EXPAND_SPARE) > (size_t)(-1) / sizeof(XML_Char)) {
+        return XML_ERROR_NO_MEMORY;
+      }
+#endif
+
       XML_Char *temp = (XML_Char *)REALLOC(
           parser, b->uri, sizeof(XML_Char) * (len + EXPAND_SPARE));
       if (temp == NULL)
@@ -3500,6 +3793,21 @@ addBinding(XML_Parser parser, PREFIX *prefix, const ATTRIBUTE_ID *attId,
     b = (BINDING *)MALLOC(parser, sizeof(BINDING));
     if (! b)
       return XML_ERROR_NO_MEMORY;
+
+    /* Detect and prevent integer overflow */
+    if (len > INT_MAX - EXPAND_SPARE) {
+      return XML_ERROR_NO_MEMORY;
+    }
+    /* Detect and prevent integer overflow.
+     * The preprocessor guard addresses the "always false" warning
+     * from -Wtype-limits on platforms where
+     * sizeof(unsigned int) < sizeof(size_t), e.g. on x86_64. */
+#if UINT_MAX >= SIZE_MAX
+    if ((unsigned)(len + EXPAND_SPARE) > (size_t)(-1) / sizeof(XML_Char)) {
+      return XML_ERROR_NO_MEMORY;
+    }
+#endif
+
     b->uri
         = (XML_Char *)MALLOC(parser, sizeof(XML_Char) * (len + EXPAND_SPARE));
     if (! b->uri) {
@@ -3535,9 +3843,9 @@ addBinding(XML_Parser parser, PREFIX *prefix, const ATTRIBUTE_ID *attId,
 static enum XML_Error PTRCALL
 cdataSectionProcessor(XML_Parser parser, const char *start, const char *end,
                       const char **endPtr) {
-  enum XML_Error result
-      = doCdataSection(parser, parser->m_encoding, &start, end, endPtr,
-                       (XML_Bool)! parser->m_parsingStatus.finalBuffer);
+  enum XML_Error result = doCdataSection(
+      parser, parser->m_encoding, &start, end, endPtr,
+      (XML_Bool)! parser->m_parsingStatus.finalBuffer, XML_ACCOUNT_DIRECT);
   if (result != XML_ERROR_NONE)
     return result;
   if (start) {
@@ -3557,7 +3865,8 @@ cdataSectionProcessor(XML_Parser parser, const char *start, const char *end,
 */
 static enum XML_Error
 doCdataSection(XML_Parser parser, const ENCODING *enc, const char **startPtr,
-               const char *end, const char **nextPtr, XML_Bool haveMore) {
+               const char *end, const char **nextPtr, XML_Bool haveMore,
+               enum XML_Account account) {
   const char *s = *startPtr;
   const char **eventPP;
   const char **eventEndPP;
@@ -3573,8 +3882,16 @@ doCdataSection(XML_Parser parser, const ENCODING *enc, const char **startPtr,
   *startPtr = NULL;
 
   for (;;) {
-    const char *next;
+    const char *next = s; /* in case of XML_TOK_NONE or XML_TOK_PARTIAL */
     int tok = XmlCdataSectionTok(enc, s, end, &next);
+#ifdef XML_DTD
+    if (! accountingDiffTolerated(parser, tok, s, next, __LINE__, account)) {
+      accountingOnAbort(parser);
+      return XML_ERROR_AMPLIFICATION_LIMIT_BREACH;
+    }
+#else
+    UNUSED_P(account);
+#endif
     *eventEndPP = next;
     switch (tok) {
     case XML_TOK_CDATA_SECT_CLOSE:
@@ -3691,7 +4008,7 @@ ignoreSectionProcessor(XML_Parser parser, const char *start, const char *end,
 static enum XML_Error
 doIgnoreSection(XML_Parser parser, const ENCODING *enc, const char **startPtr,
                 const char *end, const char **nextPtr, XML_Bool haveMore) {
-  const char *next;
+  const char *next = *startPtr; /* in case of XML_TOK_NONE or XML_TOK_PARTIAL */
   int tok;
   const char *s = *startPtr;
   const char **eventPP;
@@ -3719,6 +4036,13 @@ doIgnoreSection(XML_Parser parser, const ENCODING *enc, const char **startPtr,
   *eventPP = s;
   *startPtr = NULL;
   tok = XmlIgnoreSectionTok(enc, s, end, &next);
+#  ifdef XML_DTD
+  if (! accountingDiffTolerated(parser, tok, s, next, __LINE__,
+                                XML_ACCOUNT_DIRECT)) {
+    accountingOnAbort(parser);
+    return XML_ERROR_AMPLIFICATION_LIMIT_BREACH;
+  }
+#  endif
   *eventEndPP = next;
   switch (tok) {
   case XML_TOK_IGNORE_SECT:
@@ -3803,6 +4127,15 @@ processXmlDecl(XML_Parser parser, int isGeneralTextEntity, const char *s,
   const char *versionend;
   const XML_Char *storedversion = NULL;
   int standalone = -1;
+
+#ifdef XML_DTD
+  if (! accountingDiffTolerated(parser, XML_TOK_XML_DECL, s, next, __LINE__,
+                                XML_ACCOUNT_DIRECT)) {
+    accountingOnAbort(parser);
+    return XML_ERROR_AMPLIFICATION_LIMIT_BREACH;
+  }
+#endif
+
   if (! (parser->m_ns ? XmlParseXmlDeclNS : XmlParseXmlDecl)(
           isGeneralTextEntity, parser->m_encoding, s, next, &parser->m_eventPtr,
           &version, &versionend, &encodingName, &newEncoding, &standalone)) {
@@ -3952,6 +4285,10 @@ entityValueInitProcessor(XML_Parser parser, const char *s, const char *end,
 
   for (;;) {
     tok = XmlPrologTok(parser->m_encoding, start, end, &next);
+    /* Note: Except for XML_TOK_BOM below, these bytes are accounted later in:
+             - storeEntityValue
+             - processXmlDecl
+    */
     parser->m_eventEndPtr = next;
     if (tok <= 0) {
       if (! parser->m_parsingStatus.finalBuffer && tok != XML_TOK_INVALID) {
@@ -3970,7 +4307,8 @@ entityValueInitProcessor(XML_Parser parser, const char *s, const char *end,
         break;
       }
       /* found end of entity value - can store it now */
-      return storeEntityValue(parser, parser->m_encoding, s, end);
+      return storeEntityValue(parser, parser->m_encoding, s, end,
+                              XML_ACCOUNT_DIRECT);
     } else if (tok == XML_TOK_XML_DECL) {
       enum XML_Error result;
       result = processXmlDecl(parser, 0, start, next);
@@ -3997,6 +4335,14 @@ entityValueInitProcessor(XML_Parser parser, const char *s, const char *end,
     */
     else if (tok == XML_TOK_BOM && next == end
              && ! parser->m_parsingStatus.finalBuffer) {
+#  ifdef XML_DTD
+      if (! accountingDiffTolerated(parser, tok, s, next, __LINE__,
+                                    XML_ACCOUNT_DIRECT)) {
+        accountingOnAbort(parser);
+        return XML_ERROR_AMPLIFICATION_LIMIT_BREACH;
+      }
+#  endif
+
       *nextPtr = next;
       return XML_ERROR_NONE;
     }
@@ -4039,16 +4385,24 @@ externalParEntProcessor(XML_Parser parser, const char *s, const char *end,
   }
   /* This would cause the next stage, i.e. doProlog to be passed XML_TOK_BOM.
      However, when parsing an external subset, doProlog will not accept a BOM
-     as valid, and report a syntax error, so we have to skip the BOM
+     as valid, and report a syntax error, so we have to skip the BOM, and
+     account for the BOM bytes.
   */
   else if (tok == XML_TOK_BOM) {
+    if (! accountingDiffTolerated(parser, tok, s, next, __LINE__,
+                                  XML_ACCOUNT_DIRECT)) {
+      accountingOnAbort(parser);
+      return XML_ERROR_AMPLIFICATION_LIMIT_BREACH;
+    }
+
     s = next;
     tok = XmlPrologTok(parser->m_encoding, s, end, &next);
   }
 
   parser->m_processor = prologProcessor;
   return doProlog(parser, parser->m_encoding, s, end, tok, next, nextPtr,
-                  (XML_Bool)! parser->m_parsingStatus.finalBuffer, XML_TRUE);
+                  (XML_Bool)! parser->m_parsingStatus.finalBuffer, XML_TRUE,
+                  XML_ACCOUNT_DIRECT);
 }
 
 static enum XML_Error PTRCALL
@@ -4061,6 +4415,9 @@ entityValueProcessor(XML_Parser parser, const char *s, const char *end,
 
   for (;;) {
     tok = XmlPrologTok(enc, start, end, &next);
+    /* Note: These bytes are accounted later in:
+             - storeEntityValue
+    */
     if (tok <= 0) {
       if (! parser->m_parsingStatus.finalBuffer && tok != XML_TOK_INVALID) {
         *nextPtr = s;
@@ -4078,7 +4435,7 @@ entityValueProcessor(XML_Parser parser, const char *s, const char *end,
         break;
       }
       /* found end of entity value - can store it now */
-      return storeEntityValue(parser, enc, s, end);
+      return storeEntityValue(parser, enc, s, end, XML_ACCOUNT_DIRECT);
     }
     start = next;
   }
@@ -4092,13 +4449,14 @@ prologProcessor(XML_Parser parser, const char *s, const char *end,
   const char *next = s;
   int tok = XmlPrologTok(parser->m_encoding, s, end, &next);
   return doProlog(parser, parser->m_encoding, s, end, tok, next, nextPtr,
-                  (XML_Bool)! parser->m_parsingStatus.finalBuffer, XML_TRUE);
+                  (XML_Bool)! parser->m_parsingStatus.finalBuffer, XML_TRUE,
+                  XML_ACCOUNT_DIRECT);
 }
 
 static enum XML_Error
 doProlog(XML_Parser parser, const ENCODING *enc, const char *s, const char *end,
          int tok, const char *next, const char **nextPtr, XML_Bool haveMore,
-         XML_Bool allowClosingDoctype) {
+         XML_Bool allowClosingDoctype, enum XML_Account account) {
 #ifdef XML_DTD
   static const XML_Char externalSubsetName[] = {ASCII_HASH, '\0'};
 #endif /* XML_DTD */
@@ -4125,6 +4483,10 @@ doProlog(XML_Parser parser, const ENCODING *enc, const char *s, const char *end,
   static const XML_Char enumValueSep[] = {ASCII_PIPE, '\0'};
   static const XML_Char enumValueStart[] = {ASCII_LPAREN, '\0'};
 
+#ifndef XML_DTD
+  UNUSED_P(account);
+#endif
+
   /* save one level of indirection */
   DTD *const dtd = parser->m_dtd;
 
@@ -4189,6 +4551,19 @@ doProlog(XML_Parser parser, const ENCODING *enc, const char *s, const char *end,
       }
     }
     role = XmlTokenRole(&parser->m_prologState, tok, s, next, enc);
+#ifdef XML_DTD
+    switch (role) {
+    case XML_ROLE_INSTANCE_START: // bytes accounted in contentProcessor
+    case XML_ROLE_XML_DECL:       // bytes accounted in processXmlDecl
+    case XML_ROLE_TEXT_DECL:      // bytes accounted in processXmlDecl
+      break;
+    default:
+      if (! accountingDiffTolerated(parser, tok, s, next, __LINE__, account)) {
+        accountingOnAbort(parser);
+        return XML_ERROR_AMPLIFICATION_LIMIT_BREACH;
+      }
+    }
+#endif
     switch (role) {
     case XML_ROLE_XML_DECL: {
       enum XML_Error result = processXmlDecl(parser, 0, s, next);
@@ -4464,7 +4839,8 @@ doProlog(XML_Parser parser, const ENCODING *enc, const char *s, const char *end,
         const XML_Char *attVal;
         enum XML_Error result = storeAttributeValue(
             parser, enc, parser->m_declAttributeIsCdata,
-            s + enc->minBytesPerChar, next - enc->minBytesPerChar, &dtd->pool);
+            s + enc->minBytesPerChar, next - enc->minBytesPerChar, &dtd->pool,
+            XML_ACCOUNT_NONE);
         if (result)
           return result;
         attVal = poolStart(&dtd->pool);
@@ -4497,8 +4873,9 @@ doProlog(XML_Parser parser, const ENCODING *enc, const char *s, const char *end,
       break;
     case XML_ROLE_ENTITY_VALUE:
       if (dtd->keepProcessing) {
-        enum XML_Error result = storeEntityValue(
-            parser, enc, s + enc->minBytesPerChar, next - enc->minBytesPerChar);
+        enum XML_Error result
+            = storeEntityValue(parser, enc, s + enc->minBytesPerChar,
+                               next - enc->minBytesPerChar, XML_ACCOUNT_NONE);
         if (parser->m_declEntity) {
           parser->m_declEntity->textPtr = poolStart(&dtd->entityValuePool);
           parser->m_declEntity->textLen
@@ -4757,6 +5134,11 @@ doProlog(XML_Parser parser, const ENCODING *enc, const char *s, const char *end,
       if (parser->m_prologState.level >= parser->m_groupSize) {
         if (parser->m_groupSize) {
           {
+            /* Detect and prevent integer overflow */
+            if (parser->m_groupSize > (unsigned int)(-1) / 2u) {
+              return XML_ERROR_NO_MEMORY;
+            }
+
             char *const new_connector = (char *)REALLOC(
                 parser, parser->m_groupConnector, parser->m_groupSize *= 2);
             if (new_connector == NULL) {
@@ -4767,6 +5149,16 @@ doProlog(XML_Parser parser, const ENCODING *enc, const char *s, const char *end,
           }
 
           if (dtd->scaffIndex) {
+            /* Detect and prevent integer overflow.
+             * The preprocessor guard addresses the "always false" warning
+             * from -Wtype-limits on platforms where
+             * sizeof(unsigned int) < sizeof(size_t), e.g. on x86_64. */
+#if UINT_MAX >= SIZE_MAX
+            if (parser->m_groupSize > (size_t)(-1) / sizeof(int)) {
+              return XML_ERROR_NO_MEMORY;
+            }
+#endif
+
             int *const new_scaff_index = (int *)REALLOC(
                 parser, dtd->scaffIndex, parser->m_groupSize * sizeof(int));
             if (new_scaff_index == NULL)
@@ -4888,12 +5280,15 @@ doProlog(XML_Parser parser, const ENCODING *enc, const char *s, const char *end,
         if (parser->m_externalEntityRefHandler) {
           dtd->paramEntityRead = XML_FALSE;
           entity->open = XML_TRUE;
+          entityTrackingOnOpen(parser, entity, __LINE__);
           if (! parser->m_externalEntityRefHandler(
                   parser->m_externalEntityRefHandlerArg, 0, entity->base,
                   entity->systemId, entity->publicId)) {
+            entityTrackingOnClose(parser, entity, __LINE__);
             entity->open = XML_FALSE;
             return XML_ERROR_EXTERNAL_ENTITY_HANDLING;
           }
+          entityTrackingOnClose(parser, entity, __LINE__);
           entity->open = XML_FALSE;
           handleDefault = XML_FALSE;
           if (! dtd->paramEntityRead) {
@@ -5091,6 +5486,13 @@ epilogProcessor(XML_Parser parser, const char *s, const char *end,
   for (;;) {
     const char *next = NULL;
     int tok = XmlPrologTok(parser->m_encoding, s, end, &next);
+#ifdef XML_DTD
+    if (! accountingDiffTolerated(parser, tok, s, next, __LINE__,
+                                  XML_ACCOUNT_DIRECT)) {
+      accountingOnAbort(parser);
+      return XML_ERROR_AMPLIFICATION_LIMIT_BREACH;
+    }
+#endif
     parser->m_eventEndPtr = next;
     switch (tok) {
     /* report partial linebreak - it might be the last token */
@@ -5164,6 +5566,9 @@ processInternalEntity(XML_Parser parser, ENTITY *entity, XML_Bool betweenDecl) {
       return XML_ERROR_NO_MEMORY;
   }
   entity->open = XML_TRUE;
+#ifdef XML_DTD
+  entityTrackingOnOpen(parser, entity, __LINE__);
+#endif
   entity->processed = 0;
   openEntity->next = parser->m_openInternalEntities;
   parser->m_openInternalEntities = openEntity;
@@ -5172,8 +5577,8 @@ processInternalEntity(XML_Parser parser, ENTITY *entity, XML_Bool betweenDecl) {
   openEntity->betweenDecl = betweenDecl;
   openEntity->internalEventPtr = NULL;
   openEntity->internalEventEndPtr = NULL;
-  textStart = (char *)entity->textPtr;
-  textEnd = (char *)(entity->textPtr + entity->textLen);
+  textStart = (const char *)entity->textPtr;
+  textEnd = (const char *)(entity->textPtr + entity->textLen);
   /* Set a safe default value in case 'next' does not get set */
   next = textStart;
 
@@ -5182,17 +5587,22 @@ processInternalEntity(XML_Parser parser, ENTITY *entity, XML_Bool betweenDecl) {
     int tok
         = XmlPrologTok(parser->m_internalEncoding, textStart, textEnd, &next);
     result = doProlog(parser, parser->m_internalEncoding, textStart, textEnd,
-                      tok, next, &next, XML_FALSE, XML_FALSE);
+                      tok, next, &next, XML_FALSE, XML_FALSE,
+                      XML_ACCOUNT_ENTITY_EXPANSION);
   } else
 #endif /* XML_DTD */
     result = doContent(parser, parser->m_tagLevel, parser->m_internalEncoding,
-                       textStart, textEnd, &next, XML_FALSE);
+                       textStart, textEnd, &next, XML_FALSE,
+                       XML_ACCOUNT_ENTITY_EXPANSION);
 
   if (result == XML_ERROR_NONE) {
     if (textEnd != next && parser->m_parsingStatus.parsing == XML_SUSPENDED) {
       entity->processed = (int)(next - textStart);
       parser->m_processor = internalEntityProcessor;
     } else {
+#ifdef XML_DTD
+      entityTrackingOnClose(parser, entity, __LINE__);
+#endif /* XML_DTD */
       entity->open = XML_FALSE;
       parser->m_openInternalEntities = openEntity->next;
       /* put openEntity back in list of free instances */
@@ -5215,8 +5625,8 @@ internalEntityProcessor(XML_Parser parser, const char *s, const char *end,
     return XML_ERROR_UNEXPECTED_STATE;
 
   entity = openEntity->entity;
-  textStart = ((char *)entity->textPtr) + entity->processed;
-  textEnd = (char *)(entity->textPtr + entity->textLen);
+  textStart = ((const char *)entity->textPtr) + entity->processed;
+  textEnd = (const char *)(entity->textPtr + entity->textLen);
   /* Set a safe default value in case 'next' does not get set */
   next = textStart;
 
@@ -5225,20 +5635,24 @@ internalEntityProcessor(XML_Parser parser, const char *s, const char *end,
     int tok
         = XmlPrologTok(parser->m_internalEncoding, textStart, textEnd, &next);
     result = doProlog(parser, parser->m_internalEncoding, textStart, textEnd,
-                      tok, next, &next, XML_FALSE, XML_TRUE);
+                      tok, next, &next, XML_FALSE, XML_TRUE,
+                      XML_ACCOUNT_ENTITY_EXPANSION);
   } else
 #endif /* XML_DTD */
     result = doContent(parser, openEntity->startTagLevel,
                        parser->m_internalEncoding, textStart, textEnd, &next,
-                       XML_FALSE);
+                       XML_FALSE, XML_ACCOUNT_ENTITY_EXPANSION);
 
   if (result != XML_ERROR_NONE)
     return result;
   else if (textEnd != next
            && parser->m_parsingStatus.parsing == XML_SUSPENDED) {
-    entity->processed = (int)(next - (char *)entity->textPtr);
+    entity->processed = (int)(next - (const char *)entity->textPtr);
     return result;
   } else {
+#ifdef XML_DTD
+    entityTrackingOnClose(parser, entity, __LINE__);
+#endif
     entity->open = XML_FALSE;
     parser->m_openInternalEntities = openEntity->next;
     /* put openEntity back in list of free instances */
@@ -5252,7 +5666,8 @@ internalEntityProcessor(XML_Parser parser, const char *s, const char *end,
     parser->m_processor = prologProcessor;
     tok = XmlPrologTok(parser->m_encoding, s, end, &next);
     return doProlog(parser, parser->m_encoding, s, end, tok, next, nextPtr,
-                    (XML_Bool)! parser->m_parsingStatus.finalBuffer, XML_TRUE);
+                    (XML_Bool)! parser->m_parsingStatus.finalBuffer, XML_TRUE,
+                    XML_ACCOUNT_DIRECT);
   } else
 #endif /* XML_DTD */
   {
@@ -5260,7 +5675,8 @@ internalEntityProcessor(XML_Parser parser, const char *s, const char *end,
     /* see externalEntityContentProcessor vs contentProcessor */
     return doContent(parser, parser->m_parentParser ? 1 : 0, parser->m_encoding,
                      s, end, nextPtr,
-                     (XML_Bool)! parser->m_parsingStatus.finalBuffer);
+                     (XML_Bool)! parser->m_parsingStatus.finalBuffer,
+                     XML_ACCOUNT_DIRECT);
   }
 }
 
@@ -5275,9 +5691,10 @@ errorProcessor(XML_Parser parser, const char *s, const char *end,
 
 static enum XML_Error
 storeAttributeValue(XML_Parser parser, const ENCODING *enc, XML_Bool isCdata,
-                    const char *ptr, const char *end, STRING_POOL *pool) {
+                    const char *ptr, const char *end, STRING_POOL *pool,
+                    enum XML_Account account) {
   enum XML_Error result
-      = appendAttributeValue(parser, enc, isCdata, ptr, end, pool);
+      = appendAttributeValue(parser, enc, isCdata, ptr, end, pool, account);
   if (result)
     return result;
   if (! isCdata && poolLength(pool) && poolLastChar(pool) == 0x20)
@@ -5289,11 +5706,23 @@ storeAttributeValue(XML_Parser parser, const ENCODING *enc, XML_Bool isCdata,
 
 static enum XML_Error
 appendAttributeValue(XML_Parser parser, const ENCODING *enc, XML_Bool isCdata,
-                     const char *ptr, const char *end, STRING_POOL *pool) {
+                     const char *ptr, const char *end, STRING_POOL *pool,
+                     enum XML_Account account) {
   DTD *const dtd = parser->m_dtd; /* save one level of indirection */
+#ifndef XML_DTD
+  UNUSED_P(account);
+#endif
+
   for (;;) {
-    const char *next;
+    const char *next
+        = ptr; /* XmlAttributeValueTok doesn't always set the last arg */
     int tok = XmlAttributeValueTok(enc, ptr, end, &next);
+#ifdef XML_DTD
+    if (! accountingDiffTolerated(parser, tok, ptr, next, __LINE__, account)) {
+      accountingOnAbort(parser);
+      return XML_ERROR_AMPLIFICATION_LIMIT_BREACH;
+    }
+#endif
     switch (tok) {
     case XML_TOK_NONE:
       return XML_ERROR_NONE;
@@ -5353,6 +5782,14 @@ appendAttributeValue(XML_Parser parser, const ENCODING *enc, XML_Bool isCdata,
       XML_Char ch = (XML_Char)XmlPredefinedEntityName(
           enc, ptr + enc->minBytesPerChar, next - enc->minBytesPerChar);
       if (ch) {
+#ifdef XML_DTD
+        /* NOTE: We are replacing 4-6 characters original input for 1 character
+         *       so there is no amplification and hence recording without
+         *       protection. */
+        accountingDiffTolerated(parser, tok, (char *)&ch,
+                                ((char *)&ch) + sizeof(XML_Char), __LINE__,
+                                XML_ACCOUNT_ENTITY_EXPANSION);
+#endif /* XML_DTD */
         if (! poolAppendChar(pool, ch))
           return XML_ERROR_NO_MEMORY;
         break;
@@ -5430,9 +5867,16 @@ appendAttributeValue(XML_Parser parser, const ENCODING *enc, XML_Bool isCdata,
         enum XML_Error result;
         const XML_Char *textEnd = entity->textPtr + entity->textLen;
         entity->open = XML_TRUE;
+#ifdef XML_DTD
+        entityTrackingOnOpen(parser, entity, __LINE__);
+#endif
         result = appendAttributeValue(parser, parser->m_internalEncoding,
-                                      isCdata, (char *)entity->textPtr,
-                                      (char *)textEnd, pool);
+                                      isCdata, (const char *)entity->textPtr,
+                                      (const char *)textEnd, pool,
+                                      XML_ACCOUNT_ENTITY_EXPANSION);
+#ifdef XML_DTD
+        entityTrackingOnClose(parser, entity, __LINE__);
+#endif
         entity->open = XML_FALSE;
         if (result)
           return result;
@@ -5462,13 +5906,16 @@ appendAttributeValue(XML_Parser parser, const ENCODING *enc, XML_Bool isCdata,
 
 static enum XML_Error
 storeEntityValue(XML_Parser parser, const ENCODING *enc,
-                 const char *entityTextPtr, const char *entityTextEnd) {
+                 const char *entityTextPtr, const char *entityTextEnd,
+                 enum XML_Account account) {
   DTD *const dtd = parser->m_dtd; /* save one level of indirection */
   STRING_POOL *pool = &(dtd->entityValuePool);
   enum XML_Error result = XML_ERROR_NONE;
 #ifdef XML_DTD
   int oldInEntityValue = parser->m_prologState.inEntityValue;
   parser->m_prologState.inEntityValue = 1;
+#else
+  UNUSED_P(account);
 #endif /* XML_DTD */
   /* never return Null for the value argument in EntityDeclHandler,
      since this would indicate an external entity; therefore we
@@ -5479,8 +5926,19 @@ storeEntityValue(XML_Parser parser, const ENCODING *enc,
   }
 
   for (;;) {
-    const char *next;
+    const char *next
+        = entityTextPtr; /* XmlEntityValueTok doesn't always set the last arg */
     int tok = XmlEntityValueTok(enc, entityTextPtr, entityTextEnd, &next);
+
+#ifdef XML_DTD
+    if (! accountingDiffTolerated(parser, tok, entityTextPtr, next, __LINE__,
+                                  account)) {
+      accountingOnAbort(parser);
+      result = XML_ERROR_AMPLIFICATION_LIMIT_BREACH;
+      goto endEntityValue;
+    }
+#endif
+
     switch (tok) {
     case XML_TOK_PARAM_ENTITY_REF:
 #ifdef XML_DTD
@@ -5516,13 +5974,16 @@ storeEntityValue(XML_Parser parser, const ENCODING *enc,
           if (parser->m_externalEntityRefHandler) {
             dtd->paramEntityRead = XML_FALSE;
             entity->open = XML_TRUE;
+            entityTrackingOnOpen(parser, entity, __LINE__);
             if (! parser->m_externalEntityRefHandler(
                     parser->m_externalEntityRefHandlerArg, 0, entity->base,
                     entity->systemId, entity->publicId)) {
+              entityTrackingOnClose(parser, entity, __LINE__);
               entity->open = XML_FALSE;
               result = XML_ERROR_EXTERNAL_ENTITY_HANDLING;
               goto endEntityValue;
             }
+            entityTrackingOnClose(parser, entity, __LINE__);
             entity->open = XML_FALSE;
             if (! dtd->paramEntityRead)
               dtd->keepProcessing = dtd->standalone;
@@ -5530,9 +5991,12 @@ storeEntityValue(XML_Parser parser, const ENCODING *enc,
             dtd->keepProcessing = dtd->standalone;
         } else {
           entity->open = XML_TRUE;
+          entityTrackingOnOpen(parser, entity, __LINE__);
           result = storeEntityValue(
-              parser, parser->m_internalEncoding, (char *)entity->textPtr,
-              (char *)(entity->textPtr + entity->textLen));
+              parser, parser->m_internalEncoding, (const char *)entity->textPtr,
+              (const char *)(entity->textPtr + entity->textLen),
+              XML_ACCOUNT_ENTITY_EXPANSION);
+          entityTrackingOnClose(parser, entity, __LINE__);
           entity->open = XML_FALSE;
           if (result)
             goto endEntityValue;
@@ -5765,7 +6229,24 @@ defineAttribute(ELEMENT_TYPE *type, ATTRIBUTE_ID *attId, XML_Bool isCdata,
       }
     } else {
       DEFAULT_ATTRIBUTE *temp;
+
+      /* Detect and prevent integer overflow */
+      if (type->allocDefaultAtts > INT_MAX / 2) {
+        return 0;
+      }
+
       int count = type->allocDefaultAtts * 2;
+
+      /* Detect and prevent integer overflow.
+       * The preprocessor guard addresses the "always false" warning
+       * from -Wtype-limits on platforms where
+       * sizeof(unsigned int) < sizeof(size_t), e.g. on x86_64. */
+#if UINT_MAX >= SIZE_MAX
+      if ((unsigned)count > (size_t)(-1) / sizeof(DEFAULT_ATTRIBUTE)) {
+        return 0;
+      }
+#endif
+
       temp = (DEFAULT_ATTRIBUTE *)REALLOC(parser, type->defaultAtts,
                                           (count * sizeof(DEFAULT_ATTRIBUTE)));
       if (temp == NULL)
@@ -6416,8 +6897,20 @@ lookup(XML_Parser parser, HASH_TABLE *table, KEY name, size_t createSize) {
     /* check for overflow (table is half full) */
     if (table->used >> (table->power - 1)) {
       unsigned char newPower = table->power + 1;
+
+      /* Detect and prevent invalid shift */
+      if (newPower >= sizeof(unsigned long) * 8 /* bits per byte */) {
+        return NULL;
+      }
+
       size_t newSize = (size_t)1 << newPower;
       unsigned long newMask = (unsigned long)newSize - 1;
+
+      /* Detect and prevent integer overflow */
+      if (newSize > (size_t)(-1) / sizeof(NAMED *)) {
+        return NULL;
+      }
+
       size_t tsize = newSize * sizeof(NAMED *);
       NAMED **newV = (NAMED **)table->mem->malloc_fcn(tsize);
       if (! newV)
@@ -6487,7 +6980,7 @@ hashTableInit(HASH_TABLE *p, const XML_Memory_Handling_Suite *ms) {
 static void FASTCALL
 hashTableIterInit(HASH_TABLE_ITER *iter, const HASH_TABLE *table) {
   iter->p = table->v;
-  iter->end = iter->p + table->size;
+  iter->end = iter->p ? iter->p + table->size : NULL;
 }
 
 static NAMED *FASTCALL
@@ -6767,6 +7260,20 @@ nextScaffoldPart(XML_Parser parser) {
   if (dtd->scaffCount >= dtd->scaffSize) {
     CONTENT_SCAFFOLD *temp;
     if (dtd->scaffold) {
+      /* Detect and prevent integer overflow */
+      if (dtd->scaffSize > UINT_MAX / 2u) {
+        return -1;
+      }
+      /* Detect and prevent integer overflow.
+       * The preprocessor guard addresses the "always false" warning
+       * from -Wtype-limits on platforms where
+       * sizeof(unsigned int) < sizeof(size_t), e.g. on x86_64. */
+#if UINT_MAX >= SIZE_MAX
+      if (dtd->scaffSize > (size_t)(-1) / 2u / sizeof(CONTENT_SCAFFOLD)) {
+        return -1;
+      }
+#endif
+
       temp = (CONTENT_SCAFFOLD *)REALLOC(
           parser, dtd->scaffold, dtd->scaffSize * 2 * sizeof(CONTENT_SCAFFOLD));
       if (temp == NULL)
@@ -6836,8 +7343,26 @@ build_model(XML_Parser parser) {
   XML_Content *ret;
   XML_Content *cpos;
   XML_Char *str;
-  int allocsize = (dtd->scaffCount * sizeof(XML_Content)
-                   + (dtd->contentStringLen * sizeof(XML_Char)));
+
+  /* Detect and prevent integer overflow.
+   * The preprocessor guard addresses the "always false" warning
+   * from -Wtype-limits on platforms where
+   * sizeof(unsigned int) < sizeof(size_t), e.g. on x86_64. */
+#if UINT_MAX >= SIZE_MAX
+  if (dtd->scaffCount > (size_t)(-1) / sizeof(XML_Content)) {
+    return NULL;
+  }
+  if (dtd->contentStringLen > (size_t)(-1) / sizeof(XML_Char)) {
+    return NULL;
+  }
+#endif
+  if (dtd->scaffCount * sizeof(XML_Content)
+      > (size_t)(-1) - dtd->contentStringLen * sizeof(XML_Char)) {
+    return NULL;
+  }
+
+  const size_t allocsize = (dtd->scaffCount * sizeof(XML_Content)
+                            + (dtd->contentStringLen * sizeof(XML_Char)));
 
   ret = (XML_Content *)MALLOC(parser, allocsize);
   if (! ret)
@@ -6893,3 +7418,755 @@ copyString(const XML_Char *s, const XML_Memory_Handling_Suite *memsuite) {
   memcpy(result, s, charsRequired * sizeof(XML_Char));
   return result;
 }
+
+#ifdef XML_DTD
+
+static float
+accountingGetCurrentAmplification(XML_Parser rootParser) {
+  const XmlBigCount countBytesOutput
+      = rootParser->m_accounting.countBytesDirect
+        + rootParser->m_accounting.countBytesIndirect;
+  const float amplificationFactor
+      = rootParser->m_accounting.countBytesDirect
+            ? (countBytesOutput
+               / (float)(rootParser->m_accounting.countBytesDirect))
+            : 1.0f;
+  assert(! rootParser->m_parentParser);
+  return amplificationFactor;
+}
+
+static void
+accountingReportStats(XML_Parser originParser, const char *epilog) {
+  const XML_Parser rootParser = getRootParserOf(originParser, NULL);
+  assert(! rootParser->m_parentParser);
+
+  if (rootParser->m_accounting.debugLevel < 1) {
+    return;
+  }
+
+  const float amplificationFactor
+      = accountingGetCurrentAmplification(rootParser);
+  fprintf(stderr,
+          "expat: Accounting(%p): Direct " EXPAT_FMT_ULL(
+              "10") ", indirect " EXPAT_FMT_ULL("10") ", amplification %8.2f%s",
+          (void *)rootParser, rootParser->m_accounting.countBytesDirect,
+          rootParser->m_accounting.countBytesIndirect,
+          (double)amplificationFactor, epilog);
+}
+
+static void
+accountingOnAbort(XML_Parser originParser) {
+  accountingReportStats(originParser, " ABORTING\n");
+}
+
+static void
+accountingReportDiff(XML_Parser rootParser,
+                     unsigned int levelsAwayFromRootParser, const char *before,
+                     const char *after, ptrdiff_t bytesMore, int source_line,
+                     enum XML_Account account) {
+  assert(! rootParser->m_parentParser);
+
+  fprintf(stderr,
+          " (+" EXPAT_FMT_PTRDIFF_T("6") " bytes %s|%d, xmlparse.c:%d) %*s\"",
+          bytesMore, (account == XML_ACCOUNT_DIRECT) ? "DIR" : "EXP",
+          levelsAwayFromRootParser, source_line, 10, "");
+
+  const char ellipis[] = "[..]";
+  const size_t ellipsisLength = sizeof(ellipis) /* because compile-time */ - 1;
+  const unsigned int contextLength = 10;
+
+  /* Note: Performance is of no concern here */
+  const char *walker = before;
+  if ((rootParser->m_accounting.debugLevel >= 3)
+      || (after - before)
+             <= (ptrdiff_t)(contextLength + ellipsisLength + contextLength)) {
+    for (; walker < after; walker++) {
+      fprintf(stderr, "%s", unsignedCharToPrintable(walker[0]));
+    }
+  } else {
+    for (; walker < before + contextLength; walker++) {
+      fprintf(stderr, "%s", unsignedCharToPrintable(walker[0]));
+    }
+    fprintf(stderr, ellipis);
+    walker = after - contextLength;
+    for (; walker < after; walker++) {
+      fprintf(stderr, "%s", unsignedCharToPrintable(walker[0]));
+    }
+  }
+  fprintf(stderr, "\"\n");
+}
+
+static XML_Bool
+accountingDiffTolerated(XML_Parser originParser, int tok, const char *before,
+                        const char *after, int source_line,
+                        enum XML_Account account) {
+  /* Note: We need to check the token type *first* to be sure that
+   *       we can even access variable <after>, safely.
+   *       E.g. for XML_TOK_NONE <after> may hold an invalid pointer. */
+  switch (tok) {
+  case XML_TOK_INVALID:
+  case XML_TOK_PARTIAL:
+  case XML_TOK_PARTIAL_CHAR:
+  case XML_TOK_NONE:
+    return XML_TRUE;
+  }
+
+  if (account == XML_ACCOUNT_NONE)
+    return XML_TRUE; /* because these bytes have been accounted for, already */
+
+  unsigned int levelsAwayFromRootParser;
+  const XML_Parser rootParser
+      = getRootParserOf(originParser, &levelsAwayFromRootParser);
+  assert(! rootParser->m_parentParser);
+
+  const int isDirect
+      = (account == XML_ACCOUNT_DIRECT) && (originParser == rootParser);
+  const ptrdiff_t bytesMore = after - before;
+
+  XmlBigCount *const additionTarget
+      = isDirect ? &rootParser->m_accounting.countBytesDirect
+                 : &rootParser->m_accounting.countBytesIndirect;
+
+  /* Detect and avoid integer overflow */
+  if (*additionTarget > (XmlBigCount)(-1) - (XmlBigCount)bytesMore)
+    return XML_FALSE;
+  *additionTarget += bytesMore;
+
+  const XmlBigCount countBytesOutput
+      = rootParser->m_accounting.countBytesDirect
+        + rootParser->m_accounting.countBytesIndirect;
+  const float amplificationFactor
+      = accountingGetCurrentAmplification(rootParser);
+  const XML_Bool tolerated
+      = (countBytesOutput < rootParser->m_accounting.activationThresholdBytes)
+        || (amplificationFactor
+            <= rootParser->m_accounting.maximumAmplificationFactor);
+
+  if (rootParser->m_accounting.debugLevel >= 2) {
+    accountingReportStats(rootParser, "");
+    accountingReportDiff(rootParser, levelsAwayFromRootParser, before, after,
+                         bytesMore, source_line, account);
+  }
+
+  return tolerated;
+}
+
+unsigned long long
+testingAccountingGetCountBytesDirect(XML_Parser parser) {
+  if (! parser)
+    return 0;
+  return parser->m_accounting.countBytesDirect;
+}
+
+unsigned long long
+testingAccountingGetCountBytesIndirect(XML_Parser parser) {
+  if (! parser)
+    return 0;
+  return parser->m_accounting.countBytesIndirect;
+}
+
+static void
+entityTrackingReportStats(XML_Parser rootParser, ENTITY *entity,
+                          const char *action, int sourceLine) {
+  assert(! rootParser->m_parentParser);
+  if (rootParser->m_entity_stats.debugLevel < 1)
+    return;
+
+#  if defined(XML_UNICODE)
+  const char *const entityName = "[..]";
+#  else
+  const char *const entityName = entity->name;
+#  endif
+
+  fprintf(
+      stderr,
+      "expat: Entities(%p): Count %9d, depth %2d/%2d %*s%s%s; %s length %d (xmlparse.c:%d)\n",
+      (void *)rootParser, rootParser->m_entity_stats.countEverOpened,
+      rootParser->m_entity_stats.currentDepth,
+      rootParser->m_entity_stats.maximumDepthSeen,
+      (rootParser->m_entity_stats.currentDepth - 1) * 2, "",
+      entity->is_param ? "%" : "&", entityName, action, entity->textLen,
+      sourceLine);
+}
+
+static void
+entityTrackingOnOpen(XML_Parser originParser, ENTITY *entity, int sourceLine) {
+  const XML_Parser rootParser = getRootParserOf(originParser, NULL);
+  assert(! rootParser->m_parentParser);
+
+  rootParser->m_entity_stats.countEverOpened++;
+  rootParser->m_entity_stats.currentDepth++;
+  if (rootParser->m_entity_stats.currentDepth
+      > rootParser->m_entity_stats.maximumDepthSeen) {
+    rootParser->m_entity_stats.maximumDepthSeen++;
+  }
+
+  entityTrackingReportStats(rootParser, entity, "OPEN ", sourceLine);
+}
+
+static void
+entityTrackingOnClose(XML_Parser originParser, ENTITY *entity, int sourceLine) {
+  const XML_Parser rootParser = getRootParserOf(originParser, NULL);
+  assert(! rootParser->m_parentParser);
+
+  entityTrackingReportStats(rootParser, entity, "CLOSE", sourceLine);
+  rootParser->m_entity_stats.currentDepth--;
+}
+
+static XML_Parser
+getRootParserOf(XML_Parser parser, unsigned int *outLevelDiff) {
+  XML_Parser rootParser = parser;
+  unsigned int stepsTakenUpwards = 0;
+  while (rootParser->m_parentParser) {
+    rootParser = rootParser->m_parentParser;
+    stepsTakenUpwards++;
+  }
+  assert(! rootParser->m_parentParser);
+  if (outLevelDiff != NULL) {
+    *outLevelDiff = stepsTakenUpwards;
+  }
+  return rootParser;
+}
+
+const char *
+unsignedCharToPrintable(unsigned char c) {
+  switch (c) {
+  case 0:
+    return "\\0";
+  case 1:
+    return "\\x1";
+  case 2:
+    return "\\x2";
+  case 3:
+    return "\\x3";
+  case 4:
+    return "\\x4";
+  case 5:
+    return "\\x5";
+  case 6:
+    return "\\x6";
+  case 7:
+    return "\\x7";
+  case 8:
+    return "\\x8";
+  case 9:
+    return "\\t";
+  case 10:
+    return "\\n";
+  case 11:
+    return "\\xB";
+  case 12:
+    return "\\xC";
+  case 13:
+    return "\\r";
+  case 14:
+    return "\\xE";
+  case 15:
+    return "\\xF";
+  case 16:
+    return "\\x10";
+  case 17:
+    return "\\x11";
+  case 18:
+    return "\\x12";
+  case 19:
+    return "\\x13";
+  case 20:
+    return "\\x14";
+  case 21:
+    return "\\x15";
+  case 22:
+    return "\\x16";
+  case 23:
+    return "\\x17";
+  case 24:
+    return "\\x18";
+  case 25:
+    return "\\x19";
+  case 26:
+    return "\\x1A";
+  case 27:
+    return "\\x1B";
+  case 28:
+    return "\\x1C";
+  case 29:
+    return "\\x1D";
+  case 30:
+    return "\\x1E";
+  case 31:
+    return "\\x1F";
+  case 32:
+    return " ";
+  case 33:
+    return "!";
+  case 34:
+    return "\\\"";
+  case 35:
+    return "#";
+  case 36:
+    return "$";
+  case 37:
+    return "%";
+  case 38:
+    return "&";
+  case 39:
+    return "'";
+  case 40:
+    return "(";
+  case 41:
+    return ")";
+  case 42:
+    return "*";
+  case 43:
+    return "+";
+  case 44:
+    return ",";
+  case 45:
+    return "-";
+  case 46:
+    return ".";
+  case 47:
+    return "/";
+  case 48:
+    return "0";
+  case 49:
+    return "1";
+  case 50:
+    return "2";
+  case 51:
+    return "3";
+  case 52:
+    return "4";
+  case 53:
+    return "5";
+  case 54:
+    return "6";
+  case 55:
+    return "7";
+  case 56:
+    return "8";
+  case 57:
+    return "9";
+  case 58:
+    return ":";
+  case 59:
+    return ";";
+  case 60:
+    return "<";
+  case 61:
+    return "=";
+  case 62:
+    return ">";
+  case 63:
+    return "?";
+  case 64:
+    return "@";
+  case 65:
+    return "A";
+  case 66:
+    return "B";
+  case 67:
+    return "C";
+  case 68:
+    return "D";
+  case 69:
+    return "E";
+  case 70:
+    return "F";
+  case 71:
+    return "G";
+  case 72:
+    return "H";
+  case 73:
+    return "I";
+  case 74:
+    return "J";
+  case 75:
+    return "K";
+  case 76:
+    return "L";
+  case 77:
+    return "M";
+  case 78:
+    return "N";
+  case 79:
+    return "O";
+  case 80:
+    return "P";
+  case 81:
+    return "Q";
+  case 82:
+    return "R";
+  case 83:
+    return "S";
+  case 84:
+    return "T";
+  case 85:
+    return "U";
+  case 86:
+    return "V";
+  case 87:
+    return "W";
+  case 88:
+    return "X";
+  case 89:
+    return "Y";
+  case 90:
+    return "Z";
+  case 91:
+    return "[";
+  case 92:
+    return "\\\\";
+  case 93:
+    return "]";
+  case 94:
+    return "^";
+  case 95:
+    return "_";
+  case 96:
+    return "`";
+  case 97:
+    return "a";
+  case 98:
+    return "b";
+  case 99:
+    return "c";
+  case 100:
+    return "d";
+  case 101:
+    return "e";
+  case 102:
+    return "f";
+  case 103:
+    return "g";
+  case 104:
+    return "h";
+  case 105:
+    return "i";
+  case 106:
+    return "j";
+  case 107:
+    return "k";
+  case 108:
+    return "l";
+  case 109:
+    return "m";
+  case 110:
+    return "n";
+  case 111:
+    return "o";
+  case 112:
+    return "p";
+  case 113:
+    return "q";
+  case 114:
+    return "r";
+  case 115:
+    return "s";
+  case 116:
+    return "t";
+  case 117:
+    return "u";
+  case 118:
+    return "v";
+  case 119:
+    return "w";
+  case 120:
+    return "x";
+  case 121:
+    return "y";
+  case 122:
+    return "z";
+  case 123:
+    return "{";
+  case 124:
+    return "|";
+  case 125:
+    return "}";
+  case 126:
+    return "~";
+  case 127:
+    return "\\x7F";
+  case 128:
+    return "\\x80";
+  case 129:
+    return "\\x81";
+  case 130:
+    return "\\x82";
+  case 131:
+    return "\\x83";
+  case 132:
+    return "\\x84";
+  case 133:
+    return "\\x85";
+  case 134:
+    return "\\x86";
+  case 135:
+    return "\\x87";
+  case 136:
+    return "\\x88";
+  case 137:
+    return "\\x89";
+  case 138:
+    return "\\x8A";
+  case 139:
+    return "\\x8B";
+  case 140:
+    return "\\x8C";
+  case 141:
+    return "\\x8D";
+  case 142:
+    return "\\x8E";
+  case 143:
+    return "\\x8F";
+  case 144:
+    return "\\x90";
+  case 145:
+    return "\\x91";
+  case 146:
+    return "\\x92";
+  case 147:
+    return "\\x93";
+  case 148:
+    return "\\x94";
+  case 149:
+    return "\\x95";
+  case 150:
+    return "\\x96";
+  case 151:
+    return "\\x97";
+  case 152:
+    return "\\x98";
+  case 153:
+    return "\\x99";
+  case 154:
+    return "\\x9A";
+  case 155:
+    return "\\x9B";
+  case 156:
+    return "\\x9C";
+  case 157:
+    return "\\x9D";
+  case 158:
+    return "\\x9E";
+  case 159:
+    return "\\x9F";
+  case 160:
+    return "\\xA0";
+  case 161:
+    return "\\xA1";
+  case 162:
+    return "\\xA2";
+  case 163:
+    return "\\xA3";
+  case 164:
+    return "\\xA4";
+  case 165:
+    return "\\xA5";
+  case 166:
+    return "\\xA6";
+  case 167:
+    return "\\xA7";
+  case 168:
+    return "\\xA8";
+  case 169:
+    return "\\xA9";
+  case 170:
+    return "\\xAA";
+  case 171:
+    return "\\xAB";
+  case 172:
+    return "\\xAC";
+  case 173:
+    return "\\xAD";
+  case 174:
+    return "\\xAE";
+  case 175:
+    return "\\xAF";
+  case 176:
+    return "\\xB0";
+  case 177:
+    return "\\xB1";
+  case 178:
+    return "\\xB2";
+  case 179:
+    return "\\xB3";
+  case 180:
+    return "\\xB4";
+  case 181:
+    return "\\xB5";
+  case 182:
+    return "\\xB6";
+  case 183:
+    return "\\xB7";
+  case 184:
+    return "\\xB8";
+  case 185:
+    return "\\xB9";
+  case 186:
+    return "\\xBA";
+  case 187:
+    return "\\xBB";
+  case 188:
+    return "\\xBC";
+  case 189:
+    return "\\xBD";
+  case 190:
+    return "\\xBE";
+  case 191:
+    return "\\xBF";
+  case 192:
+    return "\\xC0";
+  case 193:
+    return "\\xC1";
+  case 194:
+    return "\\xC2";
+  case 195:
+    return "\\xC3";
+  case 196:
+    return "\\xC4";
+  case 197:
+    return "\\xC5";
+  case 198:
+    return "\\xC6";
+  case 199:
+    return "\\xC7";
+  case 200:
+    return "\\xC8";
+  case 201:
+    return "\\xC9";
+  case 202:
+    return "\\xCA";
+  case 203:
+    return "\\xCB";
+  case 204:
+    return "\\xCC";
+  case 205:
+    return "\\xCD";
+  case 206:
+    return "\\xCE";
+  case 207:
+    return "\\xCF";
+  case 208:
+    return "\\xD0";
+  case 209:
+    return "\\xD1";
+  case 210:
+    return "\\xD2";
+  case 211:
+    return "\\xD3";
+  case 212:
+    return "\\xD4";
+  case 213:
+    return "\\xD5";
+  case 214:
+    return "\\xD6";
+  case 215:
+    return "\\xD7";
+  case 216:
+    return "\\xD8";
+  case 217:
+    return "\\xD9";
+  case 218:
+    return "\\xDA";
+  case 219:
+    return "\\xDB";
+  case 220:
+    return "\\xDC";
+  case 221:
+    return "\\xDD";
+  case 222:
+    return "\\xDE";
+  case 223:
+    return "\\xDF";
+  case 224:
+    return "\\xE0";
+  case 225:
+    return "\\xE1";
+  case 226:
+    return "\\xE2";
+  case 227:
+    return "\\xE3";
+  case 228:
+    return "\\xE4";
+  case 229:
+    return "\\xE5";
+  case 230:
+    return "\\xE6";
+  case 231:
+    return "\\xE7";
+  case 232:
+    return "\\xE8";
+  case 233:
+    return "\\xE9";
+  case 234:
+    return "\\xEA";
+  case 235:
+    return "\\xEB";
+  case 236:
+    return "\\xEC";
+  case 237:
+    return "\\xED";
+  case 238:
+    return "\\xEE";
+  case 239:
+    return "\\xEF";
+  case 240:
+    return "\\xF0";
+  case 241:
+    return "\\xF1";
+  case 242:
+    return "\\xF2";
+  case 243:
+    return "\\xF3";
+  case 244:
+    return "\\xF4";
+  case 245:
+    return "\\xF5";
+  case 246:
+    return "\\xF6";
+  case 247:
+    return "\\xF7";
+  case 248:
+    return "\\xF8";
+  case 249:
+    return "\\xF9";
+  case 250:
+    return "\\xFA";
+  case 251:
+    return "\\xFB";
+  case 252:
+    return "\\xFC";
+  case 253:
+    return "\\xFD";
+  case 254:
+    return "\\xFE";
+  case 255:
+    return "\\xFF";
+  default:
+    assert(0); /* never gets here */
+    return "dead code";
+  }
+  assert(0); /* never gets here */
+}
+
+#endif /* XML_DTD */
+
+static unsigned long
+getDebugLevel(const char *variableName, unsigned long defaultDebugLevel) {
+  const char *const valueOrNull = getenv(variableName);
+  if (valueOrNull == NULL) {
+    return defaultDebugLevel;
+  }
+  const char *const value = valueOrNull;
+
+  errno = 0;
+  char *afterValue = (char *)value;
+  unsigned long debugLevel = strtoul(value, &afterValue, 10);
+  if ((errno != 0) || (afterValue[0] != '\0')) {
+    errno = 0;
+    return defaultDebugLevel;
+  }
+
+  return debugLevel;
+}
diff --git a/contrib/expat/lib/xmlrole.c b/contrib/expat/lib/xmlrole.c
index 4d3e3e86e9e8..77746ee42d10 100644
--- a/contrib/expat/lib/xmlrole.c
+++ b/contrib/expat/lib/xmlrole.c
@@ -7,7 +7,15 @@
                                  |_| XML parser
 
    Copyright (c) 1997-2000 Thai Open Source Software Center Ltd
-   Copyright (c) 2000-2017 Expat development team
+   Copyright (c) 2000      Clark Cooper <coopercc@users.sourceforge.net>
+   Copyright (c) 2002      Greg Stein <gstein@users.sourceforge.net>
+   Copyright (c) 2002-2006 Karl Waclawek <karl@waclawek.net>
+   Copyright (c) 2002-2003 Fred L. Drake, Jr. <fdrake@users.sourceforge.net>
+   Copyright (c) 2005-2009 Steven Solie <ssolie@users.sourceforge.net>
+   Copyright (c) 2016-2021 Sebastian Pipping <sebastian@pipping.org>
+   Copyright (c) 2017      Rhodri James <rhodri@wildebeest.org.uk>
+   Copyright (c) 2019      David Loffredo <loffredo@steptools.com>
+   Copyright (c) 2021      Dong-hee Na <donghee.na@python.org>
    Licensed under the MIT license:
 
    Permission is  hereby granted,  free of charge,  to any  person obtaining
@@ -30,15 +38,13 @@
    USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
 
+#include <expat_config.h>
+
 #include <stddef.h>
 
 #ifdef _WIN32
 #  include "winconfig.h"
-#else
-#  ifdef HAVE_EXPAT_CONFIG_H
-#    include <expat_config.h>
-#  endif
-#endif /* ndef _WIN32 */
+#endif
 
 #include "expat_external.h"
 #include "internal.h"
@@ -1220,6 +1226,8 @@ common(PROLOG_STATE *state, int tok) {
 #ifdef XML_DTD
   if (! state->documentEntity && tok == XML_TOK_PARAM_ENTITY_REF)
     return XML_ROLE_INNER_PARAM_ENTITY_REF;
+#else
+  UNUSED_P(tok);
 #endif
   state->handler = error;
   return XML_ROLE_ERROR;
diff --git a/contrib/expat/lib/xmlrole.h b/contrib/expat/lib/xmlrole.h
index 036aba64fd29..d6e1fa150a10 100644
--- a/contrib/expat/lib/xmlrole.h
+++ b/contrib/expat/lib/xmlrole.h
@@ -7,7 +7,10 @@
                                  |_| XML parser
 
    Copyright (c) 1997-2000 Thai Open Source Software Center Ltd
-   Copyright (c) 2000-2017 Expat development team
+   Copyright (c) 2000      Clark Cooper <coopercc@users.sourceforge.net>
+   Copyright (c) 2002      Karl Waclawek <karl@waclawek.net>
+   Copyright (c) 2002      Fred L. Drake, Jr. <fdrake@users.sourceforge.net>
+   Copyright (c) 2017      Sebastian Pipping <sebastian@pipping.org>
    Licensed under the MIT license:
 
    Permission is  hereby granted,  free of charge,  to any  person obtaining
diff --git a/contrib/expat/lib/xmltok.c b/contrib/expat/lib/xmltok.c
index 11e9d1ccdad4..502ca1adc33b 100644
--- a/contrib/expat/lib/xmltok.c
+++ b/contrib/expat/lib/xmltok.c
@@ -7,7 +7,20 @@
                                  |_| XML parser
 
    Copyright (c) 1997-2000 Thai Open Source Software Center Ltd
-   Copyright (c) 2000-2017 Expat development team
+   Copyright (c) 2000      Clark Cooper <coopercc@users.sourceforge.net>
+   Copyright (c) 2001-2003 Fred L. Drake, Jr. <fdrake@users.sourceforge.net>
+   Copyright (c) 2002      Greg Stein <gstein@users.sourceforge.net>
+   Copyright (c) 2002-2016 Karl Waclawek <karl@waclawek.net>
+   Copyright (c) 2005-2009 Steven Solie <ssolie@users.sourceforge.net>
+   Copyright (c) 2016-2021 Sebastian Pipping <sebastian@pipping.org>
+   Copyright (c) 2016      Pascal Cuoq <cuoq@trust-in-soft.com>
+   Copyright (c) 2016      Don Lewis <truckman@apache.org>
+   Copyright (c) 2017      Rhodri James <rhodri@wildebeest.org.uk>
+   Copyright (c) 2017      Alexander Bluhm <alexander.bluhm@gmx.net>
+   Copyright (c) 2017      Benbuck Nason <bnason@netflix.com>
+   Copyright (c) 2017      José Gutiérrez de la Concha <jose@zeroc.com>
+   Copyright (c) 2019      David Loffredo <loffredo@steptools.com>
+   Copyright (c) 2021      Dong-hee Na <donghee.na@python.org>
    Licensed under the MIT license:
 
    Permission is  hereby granted,  free of charge,  to any  person obtaining
@@ -30,25 +43,15 @@
    USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
 
+#include <expat_config.h>
+
 #include <stddef.h>
 #include <string.h> /* memcpy */
-
-#if defined(_MSC_VER) && (_MSC_VER <= 1700)
-/* for vs2012/11.0/1700 and earlier Visual Studio compilers */
-#  define bool int
-#  define false 0
-#  define true 1
-#else
-#  include <stdbool.h>
-#endif
+#include <stdbool.h>
 
 #ifdef _WIN32
 #  include "winconfig.h"
-#else
-#  ifdef HAVE_EXPAT_CONFIG_H
-#    include <expat_config.h>
-#  endif
-#endif /* ndef _WIN32 */
+#endif
 
 #include "expat_external.h"
 #include "internal.h"
@@ -269,8 +272,14 @@ sb_byteToAscii(const ENCODING *enc, const char *p) {
 
 #define IS_NAME_CHAR(enc, p, n) (AS_NORMAL_ENCODING(enc)->isName##n(enc, p))
 #define IS_NMSTRT_CHAR(enc, p, n) (AS_NORMAL_ENCODING(enc)->isNmstrt##n(enc, p))
-#define IS_INVALID_CHAR(enc, p, n)                                             \
-  (AS_NORMAL_ENCODING(enc)->isInvalid##n(enc, p))
+#ifdef XML_MIN_SIZE
+#  define IS_INVALID_CHAR(enc, p, n)                                           \
+    (AS_NORMAL_ENCODING(enc)->isInvalid##n                                     \
+     && AS_NORMAL_ENCODING(enc)->isInvalid##n(enc, p))
+#else
+#  define IS_INVALID_CHAR(enc, p, n)                                           \
+    (AS_NORMAL_ENCODING(enc)->isInvalid##n(enc, p))
+#endif
 
 #ifdef XML_MIN_SIZE
 #  define IS_NAME_CHAR_MINBPC(enc, p)                                          \
@@ -589,13 +598,13 @@ static const struct normal_encoding ascii_encoding
 static int PTRFASTCALL
 unicode_byte_type(char hi, char lo) {
   switch ((unsigned char)hi) {
-  /* 0xD800–0xDBFF first 16-bit code unit or high surrogate (W1) */
+  /* 0xD800-0xDBFF first 16-bit code unit or high surrogate (W1) */
   case 0xD8:
   case 0xD9:
   case 0xDA:
   case 0xDB:
     return BT_LEAD4;
-  /* 0xDC00–0xDFFF second 16-bit code unit or low surrogate (W2) */
+  /* 0xDC00-0xDFFF second 16-bit code unit or low surrogate (W2) */
   case 0xDC:
   case 0xDD:
   case 0xDE:
diff --git a/contrib/expat/lib/xmltok.h b/contrib/expat/lib/xmltok.h
index 2adbf5307bef..6f630c2f9ba9 100644
--- a/contrib/expat/lib/xmltok.h
+++ b/contrib/expat/lib/xmltok.h
@@ -7,7 +7,11 @@
                                  |_| XML parser
 
    Copyright (c) 1997-2000 Thai Open Source Software Center Ltd
-   Copyright (c) 2000-2017 Expat development team
+   Copyright (c) 2000      Clark Cooper <coopercc@users.sourceforge.net>
+   Copyright (c) 2002      Fred L. Drake, Jr. <fdrake@users.sourceforge.net>
+   Copyright (c) 2002-2005 Karl Waclawek <karl@waclawek.net>
+   Copyright (c) 2016-2017 Sebastian Pipping <sebastian@pipping.org>
+   Copyright (c) 2017      Rhodri James <rhodri@wildebeest.org.uk>
    Licensed under the MIT license:
 
    Permission is  hereby granted,  free of charge,  to any  person obtaining
diff --git a/contrib/expat/lib/xmltok_impl.c b/contrib/expat/lib/xmltok_impl.c
index c209221cd79d..0430591b4263 100644
--- a/contrib/expat/lib/xmltok_impl.c
+++ b/contrib/expat/lib/xmltok_impl.c
@@ -1,4 +1,4 @@
-/* This file is included!
+/* This file is included (from xmltok.c, 1-3 times depending on XML_MIN_SIZE)!
                             __  __            _
                          ___\ \/ /_ __   __ _| |_
                         / _ \\  /| '_ \ / _` | __|
@@ -7,7 +7,15 @@
                                  |_| XML parser
 
    Copyright (c) 1997-2000 Thai Open Source Software Center Ltd
-   Copyright (c) 2000-2017 Expat development team
+   Copyright (c) 2000      Clark Cooper <coopercc@users.sourceforge.net>
+   Copyright (c) 2002      Fred L. Drake, Jr. <fdrake@users.sourceforge.net>
+   Copyright (c) 2002-2016 Karl Waclawek <karl@waclawek.net>
+   Copyright (c) 2016-2021 Sebastian Pipping <sebastian@pipping.org>
+   Copyright (c) 2017      Rhodri James <rhodri@wildebeest.org.uk>
+   Copyright (c) 2018      Benjamin Peterson <benjamin@python.org>
+   Copyright (c) 2018      Anton Maklakov <antmak.pub@gmail.com>
+   Copyright (c) 2019      David Loffredo <loffredo@steptools.com>
+   Copyright (c) 2020      Boris Kolpackov <boris@codesynthesis.com>
    Licensed under the MIT license:
 
    Permission is  hereby granted,  free of charge,  to any  person obtaining
@@ -32,7 +40,7 @@
 
 #ifdef XML_TOK_IMPL_C
 
-#  ifndef IS_INVALID_CHAR
+#  ifndef IS_INVALID_CHAR // i.e. for UTF-16 and XML_MIN_SIZE not defined
 #    define IS_INVALID_CHAR(enc, ptr, n) (0)
 #  endif
 
@@ -1768,13 +1776,14 @@ PREFIX(updatePosition)(const ENCODING *enc, const char *ptr, const char *end,
 #  define LEAD_CASE(n)                                                         \
   case BT_LEAD##n:                                                             \
     ptr += n;                                                                  \
+    pos->columnNumber++;                                                       \
     break;
       LEAD_CASE(2)
       LEAD_CASE(3)
       LEAD_CASE(4)
 #  undef LEAD_CASE
     case BT_LF:
-      pos->columnNumber = (XML_Size)-1;
+      pos->columnNumber = 0;
       pos->lineNumber++;
       ptr += MINBPC(enc);
       break;
@@ -1783,13 +1792,13 @@ PREFIX(updatePosition)(const ENCODING *enc, const char *ptr, const char *end,
       ptr += MINBPC(enc);
       if (HAS_CHAR(enc, ptr, end) && BYTE_TYPE(enc, ptr) == BT_LF)
         ptr += MINBPC(enc);
-      pos->columnNumber = (XML_Size)-1;
+      pos->columnNumber = 0;
       break;
     default:
       ptr += MINBPC(enc);
+      pos->columnNumber++;
       break;
     }
-    pos->columnNumber++;
   }
 }
 
diff --git a/contrib/expat/lib/xmltok_impl.h b/contrib/expat/lib/xmltok_impl.h
index e925dbc7e2c8..c518aada013d 100644
--- a/contrib/expat/lib/xmltok_impl.h
+++ b/contrib/expat/lib/xmltok_impl.h
@@ -7,7 +7,8 @@
                                  |_| XML parser
 
    Copyright (c) 1997-2000 Thai Open Source Software Center Ltd
-   Copyright (c) 2000-2017 Expat development team
+   Copyright (c) 2000      Clark Cooper <coopercc@users.sourceforge.net>
+   Copyright (c) 2017-2019 Sebastian Pipping <sebastian@pipping.org>
    Licensed under the MIT license:
 
    Permission is  hereby granted,  free of charge,  to any  person obtaining
diff --git a/contrib/expat/lib/xmltok_ns.c b/contrib/expat/lib/xmltok_ns.c
index 919c74e9f97f..fbdd3e3c7b79 100644
--- a/contrib/expat/lib/xmltok_ns.c
+++ b/contrib/expat/lib/xmltok_ns.c
@@ -7,7 +7,11 @@
                                  |_| XML parser
 
    Copyright (c) 1997-2000 Thai Open Source Software Center Ltd
-   Copyright (c) 2000-2017 Expat development team
+   Copyright (c) 2000      Clark Cooper <coopercc@users.sourceforge.net>
+   Copyright (c) 2002      Greg Stein <gstein@users.sourceforge.net>
+   Copyright (c) 2002      Fred L. Drake, Jr. <fdrake@users.sourceforge.net>
+   Copyright (c) 2002-2006 Karl Waclawek <karl@waclawek.net>
+   Copyright (c) 2017-2021 Sebastian Pipping <sebastian@pipping.org>
    Licensed under the MIT license:
 
    Permission is  hereby granted,  free of charge,  to any  person obtaining
@@ -89,7 +93,7 @@ NS(XmlInitEncoding)(INIT_ENCODING *p, const ENCODING **encPtr,
 static const ENCODING *
 NS(findEncoding)(const ENCODING *enc, const char *ptr, const char *end) {
 #  define ENCODING_MAX 128
-  char buf[ENCODING_MAX];
+  char buf[ENCODING_MAX] = "";
   char *p = buf;
   int i;
   XmlUtf8Convert(enc, &ptr, end, &p, p + ENCODING_MAX - 1);
diff --git a/contrib/expat/run.sh.in b/contrib/expat/run.sh.in
index ff3fb36447ca..72f86b6dcc48 100644
--- a/contrib/expat/run.sh.in
+++ b/contrib/expat/run.sh.in
@@ -1,10 +1,45 @@
 #! /usr/bin/env bash
-# Copyright (C) 2017 Expat development team
-# Licensed under the MIT license
+#                          __  __            _
+#                       ___\ \/ /_ __   __ _| |_
+#                      / _ \\  /| '_ \ / _` | __|
+#                     |  __//  \| |_) | (_| | |_
+#                      \___/_/\_\ .__/ \__,_|\__|
+#                               |_| XML parser
+#
+# Copyright (c) 2017-2022 Sebastian Pipping <sebastian@pipping.org>
+# Licensed under the MIT license:
+#
+# Permission is  hereby granted,  free of charge,  to any  person obtaining
+# a  copy  of  this  software   and  associated  documentation  files  (the
+# "Software"),  to  deal in  the  Software  without restriction,  including
+# without  limitation the  rights  to use,  copy,  modify, merge,  publish,
+# distribute, sublicense, and/or sell copies of the Software, and to permit
+# persons  to whom  the Software  is  furnished to  do so,  subject to  the
+# following conditions:
+#
+# The above copyright  notice and this permission notice  shall be included
+# in all copies or substantial portions of the Software.
+#
+# THE  SOFTWARE  IS  PROVIDED  "AS  IS",  WITHOUT  WARRANTY  OF  ANY  KIND,
+# EXPRESS  OR IMPLIED,  INCLUDING  BUT  NOT LIMITED  TO  THE WARRANTIES  OF
+# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+# NO EVENT SHALL THE AUTHORS OR  COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+# DAMAGES OR  OTHER LIABILITY, WHETHER  IN AN  ACTION OF CONTRACT,  TORT OR
+# OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+# USE OR OTHER DEALINGS IN THE SOFTWARE.
 
 case "@host@" in
 *-mingw*)
-    exec wine "$@"
+    case "$(uname -o)" in
+    Cygwin|Msys)
+        # Windows binary on Windows host
+        exec "$@"
+        ;;
+    *)
+        # Windows binary on non-Windows host
+        exec wine "$@"
+        ;;
+    esac
     ;;
 *)
     exec "$@"
diff --git a/contrib/expat/test-driver-wrapper.sh b/contrib/expat/test-driver-wrapper.sh
index 36a185266c68..305c6f5f606b 100755
--- a/contrib/expat/test-driver-wrapper.sh
+++ b/contrib/expat/test-driver-wrapper.sh
@@ -6,7 +6,8 @@
 #                      \___/_/\_\ .__/ \__,_|\__|
 #                               |_| XML parser
 #
-# Copyright (c) 2017 Expat development team
+# Copyright (c) 2017 Sebastian Pipping <sebastian@pipping.org>
+# Copyright (c) 2019 Jeffrey Walton <noloader@gmail.com>
 # Licensed under the MIT license:
 #
 # Permission is  hereby granted,  free of charge,  to any  person obtaining
diff --git a/contrib/expat/tests/Makefile.am b/contrib/expat/tests/Makefile.am
index 742ed437dbde..cb68e11eb4ea 100644
--- a/contrib/expat/tests/Makefile.am
+++ b/contrib/expat/tests/Makefile.am
@@ -6,7 +6,9 @@
 #                      \___/_/\_\ .__/ \__,_|\__|
 #                               |_| XML parser
 #
-# Copyright (c) 2017 Expat development team
+# Copyright (c) 2017-2021 Sebastian Pipping <sebastian@pipping.org>
+# Copyright (c) 2017      Rhodri James <rhodri@wildebeest.org.uk>
+# Copyright (c) 2020      Jeffrey Walton <noloader@gmail.com>
 # Licensed under the MIT license:
 #
 # Permission is  hereby granted,  free of charge,  to any  person obtaining
@@ -30,7 +32,7 @@
 
 SUBDIRS = . benchmark
 
-AM_CPPFLAGS = -I$(srcdir)/../lib
+AM_CPPFLAGS = @AM_CPPFLAGS@ -I$(srcdir)/../lib
 
 noinst_LIBRARIES = libruntests.a
 
@@ -52,8 +54,11 @@ runtests_SOURCES = \
 runtestspp_SOURCES = \
     runtestspp.cpp
 
-runtests_LDADD = libruntests.a ../lib/libexpat.la
-runtestspp_LDADD = libruntests.a ../lib/libexpat.la
+runtests_LDADD = libruntests.a ../lib/libexpatinternal.la
+runtestspp_LDADD = libruntests.a ../lib/libexpatinternal.la
+
+runtests_LDFLAGS = @AM_LDFLAGS@ @LIBM@
+runtestspp_LDFLAGS = @AM_LDFLAGS@ @LIBM@
 
 EXTRA_DIST = \
     chardata.h \
diff --git a/contrib/expat/tests/Makefile.in b/contrib/expat/tests/Makefile.in
index b64e43b80b9c..1d382c34b5bb 100644
--- a/contrib/expat/tests/Makefile.in
+++ b/contrib/expat/tests/Makefile.in
@@ -1,7 +1,7 @@
-# Makefile.in generated by automake 1.16.1 from Makefile.am.
+# Makefile.in generated by automake 1.16.5 from Makefile.am.
 # @configure_input@
 
-# Copyright (C) 1994-2018 Free Software Foundation, Inc.
+# Copyright (C) 1994-2021 Free Software Foundation, Inc.
 
 # This Makefile.in is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
@@ -22,7 +22,9 @@
 #                      \___/_/\_\ .__/ \__,_|\__|
 #                               |_| XML parser
 #
-# Copyright (c) 2017 Expat development team
+# Copyright (c) 2017-2021 Sebastian Pipping <sebastian@pipping.org>
+# Copyright (c) 2017      Rhodri James <rhodri@wildebeest.org.uk>
+# Copyright (c) 2020      Jeffrey Walton <noloader@gmail.com>
 # Licensed under the MIT license:
 #
 # Permission is  hereby granted,  free of charge,  to any  person obtaining
@@ -154,14 +156,20 @@ am_libruntests_a_OBJECTS = chardata.$(OBJEXT) structdata.$(OBJEXT) \
 libruntests_a_OBJECTS = $(am_libruntests_a_OBJECTS)
 am_runtests_OBJECTS = runtests.$(OBJEXT)
 runtests_OBJECTS = $(am_runtests_OBJECTS)
-runtests_DEPENDENCIES = libruntests.a ../lib/libexpat.la
+runtests_DEPENDENCIES = libruntests.a ../lib/libexpatinternal.la
 AM_V_lt = $(am__v_lt_@AM_V@)
 am__v_lt_ = $(am__v_lt_@AM_DEFAULT_V@)
 am__v_lt_0 = --silent
 am__v_lt_1 = 
+runtests_LINK = $(LIBTOOL) $(AM_V_lt) --tag=CC $(AM_LIBTOOLFLAGS) \
+	$(LIBTOOLFLAGS) --mode=link $(CCLD) $(AM_CFLAGS) $(CFLAGS) \
+	$(runtests_LDFLAGS) $(LDFLAGS) -o $@
 am_runtestspp_OBJECTS = runtestspp.$(OBJEXT)
 runtestspp_OBJECTS = $(am_runtestspp_OBJECTS)
-runtestspp_DEPENDENCIES = libruntests.a ../lib/libexpat.la
+runtestspp_DEPENDENCIES = libruntests.a ../lib/libexpatinternal.la
+runtestspp_LINK = $(LIBTOOL) $(AM_V_lt) --tag=CXX $(AM_LIBTOOLFLAGS) \
+	$(LIBTOOLFLAGS) --mode=link $(CXXLD) $(AM_CXXFLAGS) \
+	$(CXXFLAGS) $(runtestspp_LDFLAGS) $(LDFLAGS) -o $@
 AM_V_P = $(am__v_P_@AM_V@)
 am__v_P_ = $(am__v_P_@AM_DEFAULT_V@)
 am__v_P_0 = false
@@ -259,8 +267,6 @@ am__define_uniq_tagged_files = \
   unique=`for i in $$list; do \
     if test -f "$$i"; then echo $$i; else echo $(srcdir)/$$i; fi; \
   done | $(am__uniquify_input)`
-ETAGS = etags
-CTAGS = ctags
 am__tty_colors_dummy = \
   mgn= red= grn= lgn= blu= brg= std=; \
   am__color_tests=no
@@ -443,6 +449,7 @@ am__set_TESTS_bases = \
   bases='$(TEST_LOGS)'; \
   bases=`for i in $$bases; do echo $$i; done | sed 's/\.log$$//'`; \
   bases=`echo $$bases`
+AM_TESTSUITE_SUMMARY_HEADER = ' for $(PACKAGE_STRING)'
 RECHECK_LOGS = $(TEST_LOGS)
 TEST_SUITE_LOG = test-suite.log
 TEST_EXTENSIONS = @EXEEXT@ .test
@@ -495,7 +502,11 @@ am__relativize = \
   reldir="$$dir2"
 ACLOCAL = @ACLOCAL@
 AMTAR = @AMTAR@
+AM_CFLAGS = @AM_CFLAGS@
+AM_CPPFLAGS = @AM_CPPFLAGS@ -I$(srcdir)/../lib
+AM_CXXFLAGS = @AM_CXXFLAGS@
 AM_DEFAULT_VERBOSITY = @AM_DEFAULT_VERBOSITY@
+AM_LDFLAGS = @AM_LDFLAGS@
 AR = @AR@
 AS = @AS@
 AUTOCONF = @AUTOCONF@
@@ -505,8 +516,9 @@ AWK = @AWK@
 CC = @CC@
 CCDEPMODE = @CCDEPMODE@
 CFLAGS = @CFLAGS@
-CPP = @CPP@
 CPPFLAGS = @CPPFLAGS@
+CSCOPE = @CSCOPE@
+CTAGS = @CTAGS@
 CXX = @CXX@
 CXXCPP = @CXXCPP@
 CXXDEPMODE = @CXXDEPMODE@
@@ -522,7 +534,15 @@ ECHO_C = @ECHO_C@
 ECHO_N = @ECHO_N@
 ECHO_T = @ECHO_T@
 EGREP = @EGREP@
+ETAGS = @ETAGS@
 EXEEXT = @EXEEXT@
+EXPAT_ATTR_INFO = @EXPAT_ATTR_INFO@
+EXPAT_CHAR_TYPE = @EXPAT_CHAR_TYPE@
+EXPAT_CONTEXT_BYTES = @EXPAT_CONTEXT_BYTES@
+EXPAT_DTD = @EXPAT_DTD@
+EXPAT_LARGE_SIZE = @EXPAT_LARGE_SIZE@
+EXPAT_MIN_SIZE = @EXPAT_MIN_SIZE@
+EXPAT_NS = @EXPAT_NS@
 FGREP = @FGREP@
 FILEMAP = @FILEMAP@
 GREP = @GREP@
@@ -535,6 +555,8 @@ LD = @LD@
 LDFLAGS = @LDFLAGS@
 LIBAGE = @LIBAGE@
 LIBCURRENT = @LIBCURRENT@
+LIBDIR_BASENAME = @LIBDIR_BASENAME@
+LIBM = @LIBM@
 LIBOBJS = @LIBOBJS@
 LIBREVISION = @LIBREVISION@
 LIBS = @LIBS@
@@ -564,6 +586,9 @@ RANLIB = @RANLIB@
 SED = @SED@
 SET_MAKE = @SET_MAKE@
 SHELL = @SHELL@
+SO_MAJOR = @SO_MAJOR@
+SO_MINOR = @SO_MINOR@
+SO_PATCH = @SO_PATCH@
 STRIP = @STRIP@
 VERSION = @VERSION@
 abs_builddir = @abs_builddir@
@@ -574,6 +599,7 @@ ac_ct_AR = @ac_ct_AR@
 ac_ct_CC = @ac_ct_CC@
 ac_ct_CXX = @ac_ct_CXX@
 ac_ct_DUMPBIN = @ac_ct_DUMPBIN@
+ac_cv_sizeof_void_p = @ac_cv_sizeof_void_p@
 am__include = @am__include@
 am__leading_dot = @am__leading_dot@
 am__quote = @am__quote@
@@ -611,6 +637,7 @@ pdfdir = @pdfdir@
 prefix = @prefix@
 program_transform_name = @program_transform_name@
 psdir = @psdir@
+runstatedir = @runstatedir@
 sbindir = @sbindir@
 sharedstatedir = @sharedstatedir@
 srcdir = @srcdir@
@@ -620,7 +647,6 @@ top_build_prefix = @top_build_prefix@
 top_builddir = @top_builddir@
 top_srcdir = @top_srcdir@
 SUBDIRS = . benchmark
-AM_CPPFLAGS = -I$(srcdir)/../lib
 noinst_LIBRARIES = libruntests.a
 
 # To support MinGW and Non-MinGW at the same time:
@@ -637,8 +663,10 @@ runtests_SOURCES = \
 runtestspp_SOURCES = \
     runtestspp.cpp
 
-runtests_LDADD = libruntests.a ../lib/libexpat.la
-runtestspp_LDADD = libruntests.a ../lib/libexpat.la
+runtests_LDADD = libruntests.a ../lib/libexpatinternal.la
+runtestspp_LDADD = libruntests.a ../lib/libexpatinternal.la
+runtests_LDFLAGS = @AM_LDFLAGS@ @LIBM@
+runtestspp_LDFLAGS = @AM_LDFLAGS@ @LIBM@
 EXTRA_DIST = \
     chardata.h \
     structdata.h \
@@ -702,11 +730,11 @@ libruntests.a: $(libruntests_a_OBJECTS) $(libruntests_a_DEPENDENCIES) $(EXTRA_li
 
 runtests$(EXEEXT): $(runtests_OBJECTS) $(runtests_DEPENDENCIES) $(EXTRA_runtests_DEPENDENCIES) 
 	@rm -f runtests$(EXEEXT)
-	$(AM_V_CCLD)$(LINK) $(runtests_OBJECTS) $(runtests_LDADD) $(LIBS)
+	$(AM_V_CCLD)$(runtests_LINK) $(runtests_OBJECTS) $(runtests_LDADD) $(LIBS)
 
 runtestspp$(EXEEXT): $(runtestspp_OBJECTS) $(runtestspp_DEPENDENCIES) $(EXTRA_runtestspp_DEPENDENCIES) 
 	@rm -f runtestspp$(EXEEXT)
-	$(AM_V_CXXLD)$(CXXLINK) $(runtestspp_OBJECTS) $(runtestspp_LDADD) $(LIBS)
+	$(AM_V_CXXLD)$(runtestspp_LINK) $(runtestspp_OBJECTS) $(runtestspp_LDADD) $(LIBS)
 
 mostlyclean-compile:
 	-rm -f *.$(OBJEXT)
@@ -981,7 +1009,7 @@ $(TEST_SUITE_LOG): $(TEST_LOGS)
 	  test x"$$VERBOSE" = x || cat $(TEST_SUITE_LOG);		\
 	fi;								\
 	echo "$${col}$$br$${std}"; 					\
-	echo "$${col}Testsuite summary for $(PACKAGE_STRING)$${std}";	\
+	echo "$${col}Testsuite summary"$(AM_TESTSUITE_SUMMARY_HEADER)"$${std}";	\
 	echo "$${col}$$br$${std}"; 					\
 	create_testsuite_report --maybe-color;				\
 	echo "$$col$$br$$std";						\
@@ -1043,7 +1071,6 @@ runtestspp.log: runtestspp$(EXEEXT)
 @am__EXEEXT_TRUE@	--log-file $$b.log --trs-file $$b.trs \
 @am__EXEEXT_TRUE@	$(am__common_driver_flags) $(AM_TEST_LOG_DRIVER_FLAGS) $(TEST_LOG_DRIVER_FLAGS) -- $(TEST_LOG_COMPILE) \
 @am__EXEEXT_TRUE@	"$$tst" $(AM_TESTS_FD_REDIRECT)
-
 distdir: $(BUILT_SOURCES)
 	$(MAKE) $(AM_MAKEFLAGS) distdir-am
 
diff --git a/contrib/expat/tests/benchmark/Makefile.am b/contrib/expat/tests/benchmark/Makefile.am
index f4d7a8e2c3eb..f1bf3365f63c 100644
--- a/contrib/expat/tests/benchmark/Makefile.am
+++ b/contrib/expat/tests/benchmark/Makefile.am
@@ -6,7 +6,8 @@
 #                      \___/_/\_\ .__/ \__,_|\__|
 #                               |_| XML parser
 #
-# Copyright (c) 2017 Expat development team
+# Copyright (c) 2017 Sebastian Pipping <sebastian@pipping.org>
+# Copyright (c) 2020 Jeffrey Walton <noloader@gmail.com>
 # Licensed under the MIT license:
 #
 # Permission is  hereby granted,  free of charge,  to any  person obtaining
@@ -28,7 +29,7 @@
 # OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 # USE OR OTHER DEALINGS IN THE SOFTWARE.
 
-AM_CPPFLAGS = -I$(srcdir)/../../lib
+AM_CPPFLAGS = @AM_CPPFLAGS@ -I$(srcdir)/../../lib
 
 noinst_PROGRAMS = benchmark
 
diff --git a/contrib/expat/tests/benchmark/Makefile.in b/contrib/expat/tests/benchmark/Makefile.in
index 410ee04106d2..7bf8068b1942 100644
--- a/contrib/expat/tests/benchmark/Makefile.in
+++ b/contrib/expat/tests/benchmark/Makefile.in
@@ -1,7 +1,7 @@
-# Makefile.in generated by automake 1.16.1 from Makefile.am.
+# Makefile.in generated by automake 1.16.5 from Makefile.am.
 # @configure_input@
 
-# Copyright (C) 1994-2018 Free Software Foundation, Inc.
+# Copyright (C) 1994-2021 Free Software Foundation, Inc.
 
 # This Makefile.in is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
@@ -22,7 +22,8 @@
 #                      \___/_/\_\ .__/ \__,_|\__|
 #                               |_| XML parser
 #
-# Copyright (c) 2017 Expat development team
+# Copyright (c) 2017 Sebastian Pipping <sebastian@pipping.org>
+# Copyright (c) 2020 Jeffrey Walton <noloader@gmail.com>
 # Licensed under the MIT license:
 #
 # Permission is  hereby granted,  free of charge,  to any  person obtaining
@@ -207,14 +208,16 @@ am__define_uniq_tagged_files = \
   unique=`for i in $$list; do \
     if test -f "$$i"; then echo $$i; else echo $(srcdir)/$$i; fi; \
   done | $(am__uniquify_input)`
-ETAGS = etags
-CTAGS = ctags
 am__DIST_COMMON = $(srcdir)/Makefile.in \
 	$(top_srcdir)/conftools/depcomp
 DISTFILES = $(DIST_COMMON) $(DIST_SOURCES) $(TEXINFOS) $(EXTRA_DIST)
 ACLOCAL = @ACLOCAL@
 AMTAR = @AMTAR@
+AM_CFLAGS = @AM_CFLAGS@
+AM_CPPFLAGS = @AM_CPPFLAGS@ -I$(srcdir)/../../lib
+AM_CXXFLAGS = @AM_CXXFLAGS@
 AM_DEFAULT_VERBOSITY = @AM_DEFAULT_VERBOSITY@
+AM_LDFLAGS = @AM_LDFLAGS@
 AR = @AR@
 AS = @AS@
 AUTOCONF = @AUTOCONF@
@@ -224,8 +227,9 @@ AWK = @AWK@
 CC = @CC@
 CCDEPMODE = @CCDEPMODE@
 CFLAGS = @CFLAGS@
-CPP = @CPP@
 CPPFLAGS = @CPPFLAGS@
+CSCOPE = @CSCOPE@
+CTAGS = @CTAGS@
 CXX = @CXX@
 CXXCPP = @CXXCPP@
 CXXDEPMODE = @CXXDEPMODE@
@@ -241,7 +245,15 @@ ECHO_C = @ECHO_C@
 ECHO_N = @ECHO_N@
 ECHO_T = @ECHO_T@
 EGREP = @EGREP@
+ETAGS = @ETAGS@
 EXEEXT = @EXEEXT@
+EXPAT_ATTR_INFO = @EXPAT_ATTR_INFO@
+EXPAT_CHAR_TYPE = @EXPAT_CHAR_TYPE@
+EXPAT_CONTEXT_BYTES = @EXPAT_CONTEXT_BYTES@
+EXPAT_DTD = @EXPAT_DTD@
+EXPAT_LARGE_SIZE = @EXPAT_LARGE_SIZE@
+EXPAT_MIN_SIZE = @EXPAT_MIN_SIZE@
+EXPAT_NS = @EXPAT_NS@
 FGREP = @FGREP@
 FILEMAP = @FILEMAP@
 GREP = @GREP@
@@ -254,6 +266,8 @@ LD = @LD@
 LDFLAGS = @LDFLAGS@
 LIBAGE = @LIBAGE@
 LIBCURRENT = @LIBCURRENT@
+LIBDIR_BASENAME = @LIBDIR_BASENAME@
+LIBM = @LIBM@
 LIBOBJS = @LIBOBJS@
 LIBREVISION = @LIBREVISION@
 LIBS = @LIBS@
@@ -283,6 +297,9 @@ RANLIB = @RANLIB@
 SED = @SED@
 SET_MAKE = @SET_MAKE@
 SHELL = @SHELL@
+SO_MAJOR = @SO_MAJOR@
+SO_MINOR = @SO_MINOR@
+SO_PATCH = @SO_PATCH@
 STRIP = @STRIP@
 VERSION = @VERSION@
 abs_builddir = @abs_builddir@
@@ -293,6 +310,7 @@ ac_ct_AR = @ac_ct_AR@
 ac_ct_CC = @ac_ct_CC@
 ac_ct_CXX = @ac_ct_CXX@
 ac_ct_DUMPBIN = @ac_ct_DUMPBIN@
+ac_cv_sizeof_void_p = @ac_cv_sizeof_void_p@
 am__include = @am__include@
 am__leading_dot = @am__leading_dot@
 am__quote = @am__quote@
@@ -330,6 +348,7 @@ pdfdir = @pdfdir@
 prefix = @prefix@
 program_transform_name = @program_transform_name@
 psdir = @psdir@
+runstatedir = @runstatedir@
 sbindir = @sbindir@
 sharedstatedir = @sharedstatedir@
 srcdir = @srcdir@
@@ -338,7 +357,6 @@ target_alias = @target_alias@
 top_build_prefix = @top_build_prefix@
 top_builddir = @top_builddir@
 top_srcdir = @top_srcdir@
-AM_CPPFLAGS = -I$(srcdir)/../../lib
 benchmark_SOURCES = benchmark.c
 benchmark_LDADD = ../../lib/libexpat.la
 EXTRA_DIST = \
@@ -483,7 +501,6 @@ cscopelist-am: $(am__tagged_files)
 
 distclean-tags:
 	-rm -f TAGS ID GTAGS GRTAGS GSYMS GPATH tags
-
 distdir: $(BUILT_SOURCES)
 	$(MAKE) $(AM_MAKEFLAGS) distdir-am
 
diff --git a/contrib/expat/tests/benchmark/benchmark.c b/contrib/expat/tests/benchmark/benchmark.c
index fda8268f189f..ba2bc6e1fa22 100644
--- a/contrib/expat/tests/benchmark/benchmark.c
+++ b/contrib/expat/tests/benchmark/benchmark.c
@@ -6,8 +6,10 @@
                         \___/_/\_\ .__/ \__,_|\__|
                                  |_| XML parser
 
-   Copyright (c) 1997-2000 Thai Open Source Software Center Ltd
-   Copyright (c) 2000-2017 Expat development team
+   Copyright (c) 2003-2006 Karl Waclawek <karl@waclawek.net>
+   Copyright (c) 2005-2007 Steven Solie <ssolie@users.sourceforge.net>
+   Copyright (c) 2017      Sebastian Pipping <sebastian@pipping.org>
+   Copyright (c) 2017      Rhodri James <rhodri@wildebeest.org.uk>
    Licensed under the MIT license:
 
    Permission is  hereby granted,  free of charge,  to any  person obtaining
diff --git a/contrib/expat/tests/benchmark/benchmark.sln b/contrib/expat/tests/benchmark/benchmark.sln
deleted file mode 100644
index bc790bc0c59b..000000000000
--- a/contrib/expat/tests/benchmark/benchmark.sln
+++ /dev/null
@@ -1,25 +0,0 @@
-
-Microsoft Visual Studio Solution File, Format Version 12.00
-# Visual Studio 2013
-VisualStudioVersion = 12.0.40629.0
-MinimumVisualStudioVersion = 10.0.40219.1
-Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "benchmark", "benchmark.vcxproj", "{FF89BA66-62C4-49EC-9189-1E7B603A1FD6}"
-EndProject
-Global
-	GlobalSection(SolutionConfigurationPlatforms) = preSolution
-		Debug|Win32 = Debug|Win32
-		Release|Win32 = Release|Win32
-		Template|Win32 = Template|Win32
-	EndGlobalSection
-	GlobalSection(ProjectConfigurationPlatforms) = postSolution
-		{FF89BA66-62C4-49EC-9189-1E7B603A1FD6}.Debug|Win32.ActiveCfg = Debug|Win32
-		{FF89BA66-62C4-49EC-9189-1E7B603A1FD6}.Debug|Win32.Build.0 = Debug|Win32
-		{FF89BA66-62C4-49EC-9189-1E7B603A1FD6}.Release|Win32.ActiveCfg = Release|Win32
-		{FF89BA66-62C4-49EC-9189-1E7B603A1FD6}.Release|Win32.Build.0 = Release|Win32
-		{FF89BA66-62C4-49EC-9189-1E7B603A1FD6}.Template|Win32.ActiveCfg = Template|Win32
-		{FF89BA66-62C4-49EC-9189-1E7B603A1FD6}.Template|Win32.Build.0 = Template|Win32
-	EndGlobalSection
-	GlobalSection(SolutionProperties) = preSolution
-		HideSolutionNode = FALSE
-	EndGlobalSection
-EndGlobal
diff --git a/contrib/expat/tests/chardata.c b/contrib/expat/tests/chardata.c
index 75a50166ec52..d1989a840034 100644
--- a/contrib/expat/tests/chardata.c
+++ b/contrib/expat/tests/chardata.c
@@ -6,8 +6,12 @@
                         \___/_/\_\ .__/ \__,_|\__|
                                  |_| XML parser
 
-   Copyright (c) 1997-2000 Thai Open Source Software Center Ltd
-   Copyright (c) 2000-2017 Expat development team
+   Copyright (c) 2002-2004 Fred L. Drake, Jr. <fdrake@users.sourceforge.net>
+   Copyright (c) 2003      Greg Stein <gstein@users.sourceforge.net>
+   Copyright (c) 2016      Gilles Espinasse <g.esp@free.fr>
+   Copyright (c) 2016-2021 Sebastian Pipping <sebastian@pipping.org>
+   Copyright (c) 2017      Joe Orton <jorton@redhat.com>
+   Copyright (c) 2017      Rhodri James <rhodri@wildebeest.org.uk>
    Licensed under the MIT license:
 
    Permission is  hereby granted,  free of charge,  to any  person obtaining
@@ -30,9 +34,7 @@
    USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
 
-#ifdef HAVE_EXPAT_CONFIG_H
-#  include <expat_config.h>
-#endif
+#include <expat_config.h>
 #include "minicheck.h"
 
 #include <assert.h>
diff --git a/contrib/expat/tests/chardata.h b/contrib/expat/tests/chardata.h
index 4001b9b9d157..ccb631f64b22 100644
--- a/contrib/expat/tests/chardata.h
+++ b/contrib/expat/tests/chardata.h
@@ -7,8 +7,9 @@
                         \___/_/\_\ .__/ \__,_|\__|
                                  |_| XML parser
 
-   Copyright (c) 1997-2000 Thai Open Source Software Center Ltd
-   Copyright (c) 2000-2017 Expat development team
+   Copyright (c) 2002-2004 Fred L. Drake, Jr. <fdrake@users.sourceforge.net>
+   Copyright (c) 2017      Rhodri James <rhodri@wildebeest.org.uk>
+   Copyright (c) 2017      Sebastian Pipping <sebastian@pipping.org>
    Licensed under the MIT license:
 
    Permission is  hereby granted,  free of charge,  to any  person obtaining
diff --git a/contrib/expat/tests/memcheck.c b/contrib/expat/tests/memcheck.c
index 41355f6c8d91..48822e5dbdf1 100644
--- a/contrib/expat/tests/memcheck.c
+++ b/contrib/expat/tests/memcheck.c
@@ -6,8 +6,8 @@
                         \___/_/\_\ .__/ \__,_|\__|
                                  |_| XML parser
 
-   Copyright (c) 1997-2000 Thai Open Source Software Center Ltd
-   Copyright (c) 2000-2017 Expat development team
+   Copyright (c) 2017 Rhodri James <rhodri@wildebeest.org.uk>
+   Copyright (c) 2017 Sebastian Pipping <sebastian@pipping.org>
    Licensed under the MIT license:
 
    Permission is  hereby granted,  free of charge,  to any  person obtaining
diff --git a/contrib/expat/tests/memcheck.h b/contrib/expat/tests/memcheck.h
index 4d20f4bb972d..4c0cb7281b91 100644
--- a/contrib/expat/tests/memcheck.h
+++ b/contrib/expat/tests/memcheck.h
@@ -7,8 +7,8 @@
                         \___/_/\_\ .__/ \__,_|\__|
                                  |_| XML parser
 
-   Copyright (c) 1997-2000 Thai Open Source Software Center Ltd
-   Copyright (c) 2000-2017 Expat development team
+   Copyright (c) 2017 Rhodri James <rhodri@wildebeest.org.uk>
+   Copyright (c) 2017 Sebastian Pipping <sebastian@pipping.org>
    Licensed under the MIT license:
 
    Permission is  hereby granted,  free of charge,  to any  person obtaining
diff --git a/contrib/expat/tests/minicheck.c b/contrib/expat/tests/minicheck.c
index a5a1efb159f5..1c657481f7fd 100644
--- a/contrib/expat/tests/minicheck.c
+++ b/contrib/expat/tests/minicheck.c
@@ -10,8 +10,11 @@
                         \___/_/\_\ .__/ \__,_|\__|
                                  |_| XML parser
 
-   Copyright (c) 1997-2000 Thai Open Source Software Center Ltd
-   Copyright (c) 2000-2017 Expat development team
+   Copyright (c) 2004-2006 Fred L. Drake, Jr. <fdrake@users.sourceforge.net>
+   Copyright (c) 2016-2020 Sebastian Pipping <sebastian@pipping.org>
+   Copyright (c) 2017      Rhodri James <rhodri@wildebeest.org.uk>
+   Copyright (c) 2018      Marco Maggi <marco.maggi-ipsu@poste.it>
+   Copyright (c) 2019      David Loffredo <loffredo@steptools.com>
    Licensed under the MIT license:
 
    Permission is  hereby granted,  free of charge,  to any  person obtaining
@@ -141,11 +144,18 @@ _check_set_test_info(char const *function, char const *filename, int lineno) {
 }
 
 static void
-add_failure(SRunner *runner, int verbosity) {
-  runner->nfailures++;
+handle_success(int verbosity) {
   if (verbosity >= CK_VERBOSE) {
-    printf("%s:%d: %s\n", _check_current_filename, _check_current_lineno,
-           _check_current_function);
+    printf("PASS: %s\n", _check_current_function);
+  }
+}
+
+static void
+handle_failure(SRunner *runner, int verbosity, const char *phase_info) {
+  runner->nfailures++;
+  if (verbosity != CK_SILENT) {
+    printf("FAIL: %s (%s at %s:%d)\n", _check_current_function, phase_info,
+           _check_current_filename, _check_current_lineno);
   }
 }
 
@@ -164,14 +174,14 @@ srunner_run_all(SRunner *runner, int verbosity) {
       if (tc->setup != NULL) {
         /* setup */
         if (setjmp(env)) {
-          add_failure(runner, verbosity);
+          handle_failure(runner, verbosity, "during setup");
           continue;
         }
         tc->setup();
       }
       /* test */
       if (setjmp(env)) {
-        add_failure(runner, verbosity);
+        handle_failure(runner, verbosity, "during actual test");
         continue;
       }
       (tc->tests[i])();
@@ -179,15 +189,17 @@ srunner_run_all(SRunner *runner, int verbosity) {
       /* teardown */
       if (tc->teardown != NULL) {
         if (setjmp(env)) {
-          add_failure(runner, verbosity);
+          handle_failure(runner, verbosity, "during teardown");
           continue;
         }
         tc->teardown();
       }
+
+      handle_success(verbosity);
     }
     tc = tc->next_tcase;
   }
-  if (verbosity) {
+  if (verbosity != CK_SILENT) {
     int passed = runner->nchecks - runner->nfailures;
     double percentage = ((double)passed) / runner->nchecks;
     int display = (int)(percentage * 100);
@@ -203,8 +215,8 @@ _fail_unless(int condition, const char *file, int line, const char *msg) {
      it is.
   */
   UNUSED_P(condition);
-  UNUSED_P(file);
-  UNUSED_P(line);
+  _check_current_filename = file;
+  _check_current_lineno = line;
   if (msg != NULL) {
     const int has_newline = (msg[strlen(msg) - 1] == '\n');
     fprintf(stderr, "ERROR: %s%s", msg, has_newline ? "" : "\n");
diff --git a/contrib/expat/tests/minicheck.h b/contrib/expat/tests/minicheck.h
index 88a16584fb5b..cc1f835340fe 100644
--- a/contrib/expat/tests/minicheck.h
+++ b/contrib/expat/tests/minicheck.h
@@ -12,8 +12,9 @@
                         \___/_/\_\ .__/ \__,_|\__|
                                  |_| XML parser
 
-   Copyright (c) 1997-2000 Thai Open Source Software Center Ltd
-   Copyright (c) 2000-2017 Expat development team
+   Copyright (c) 2004-2006 Fred L. Drake, Jr. <fdrake@users.sourceforge.net>
+   Copyright (c) 2006-2012 Karl Waclawek <karl@waclawek.net>
+   Copyright (c) 2016-2017 Sebastian Pipping <sebastian@pipping.org>
    Licensed under the MIT license:
 
    Permission is  hereby granted,  free of charge,  to any  person obtaining
diff --git a/contrib/expat/tests/runtests.c b/contrib/expat/tests/runtests.c
index b7411e925900..d2923ac1fd58 100644
--- a/contrib/expat/tests/runtests.c
+++ b/contrib/expat/tests/runtests.c
@@ -6,8 +6,18 @@
                         \___/_/\_\ .__/ \__,_|\__|
                                  |_| XML parser
 
-   Copyright (c) 1997-2000 Thai Open Source Software Center Ltd
-   Copyright (c) 2000-2017 Expat development team
+   Copyright (c) 2001-2006 Fred L. Drake, Jr. <fdrake@users.sourceforge.net>
+   Copyright (c) 2003      Greg Stein <gstein@users.sourceforge.net>
+   Copyright (c) 2005-2007 Steven Solie <ssolie@users.sourceforge.net>
+   Copyright (c) 2005-2012 Karl Waclawek <karl@waclawek.net>
+   Copyright (c) 2016-2022 Sebastian Pipping <sebastian@pipping.org>
+   Copyright (c) 2017-2018 Rhodri James <rhodri@wildebeest.org.uk>
+   Copyright (c) 2017      Joe Orton <jorton@redhat.com>
+   Copyright (c) 2017      José Gutiérrez de la Concha <jose@zeroc.com>
+   Copyright (c) 2018      Marco Maggi <marco.maggi-ipsu@poste.it>
+   Copyright (c) 2019      David Loffredo <loffredo@steptools.com>
+   Copyright (c) 2020      Tim Gates <tim.gates@iress.com>
+   Copyright (c) 2021      Dong-hee Na <donghee.na@python.org>
    Licensed under the MIT license:
 
    Permission is  hereby granted,  free of charge,  to any  person obtaining
@@ -30,14 +40,12 @@
    USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
 
+#include <expat_config.h>
+
 #if defined(NDEBUG)
 #  undef NDEBUG /* because test suite relies on assert(...) at the moment */
 #endif
 
-#ifdef HAVE_EXPAT_CONFIG_H
-#  include <expat_config.h>
-#endif
-
 #include <assert.h>
 #include <stdlib.h>
 #include <stdio.h>
@@ -45,34 +53,17 @@
 #include <stddef.h> /* ptrdiff_t */
 #include <ctype.h>
 #include <limits.h>
-
-#if defined(_WIN32) && defined(_MSC_VER) && (_MSC_VER < 1600)
-/* For vs2003/7.1 up to vs2008/9.0; _MSC_VER 1600 is vs2010/10.0 */
-#  if defined(_WIN64)
-typedef __int64 intptr_t;
-#  else
-typedef __int32 intptr_t;
-#  endif
-typedef unsigned __int64 uint64_t;
-#else
-#  include <stdint.h> /* intptr_t uint64_t */
-#endif
+#include <stdint.h> /* intptr_t uint64_t */
+#include <math.h>   /* NAN, INFINITY, isnan */
 
 #if ! defined(__cplusplus)
-#  if defined(_MSC_VER) && (_MSC_VER <= 1700)
-/* for vs2012/11.0/1700 and earlier Visual Studio compilers */
-#    define bool int
-#    define false 0
-#    define true 1
-#  else
-#    include <stdbool.h>
-#  endif
+#  include <stdbool.h>
 #endif
 
 #include "expat.h"
 #include "chardata.h"
 #include "structdata.h"
-#include "internal.h" /* for UNUSED_P only */
+#include "internal.h"
 #include "minicheck.h"
 #include "memcheck.h"
 #include "siphash.h"
@@ -109,6 +100,16 @@ typedef unsigned __int64 uint64_t;
 static XML_Parser g_parser = NULL;
 
 static void
+tcase_add_test__ifdef_xml_dtd(TCase *tc, tcase_test_function test) {
+#ifdef XML_DTD
+  tcase_add_test(tc, test);
+#else
+  UNUSED_P(tc);
+  UNUSED_P(test);
+#endif
+}
+
+static void
 basic_setup(void) {
   g_parser = XML_ParserCreate(NULL);
   if (g_parser == NULL)
@@ -1769,7 +1770,7 @@ START_TEST(test_not_standalone_handler_accept) {
   XML_SetNotStandaloneHandler(g_parser, accept_not_standalone_handler);
   run_ext_character_check(text, &test_data, XCS(""));
 
-  /* Repeat wtihout the external entity handler */
+  /* Repeat without the external entity handler */
   XML_ParserReset(g_parser, NULL);
   XML_SetNotStandaloneHandler(g_parser, accept_not_standalone_handler);
   run_character_check(text, XCS(""));
@@ -7049,17 +7050,39 @@ END_TEST
 /* Test that too many colons are rejected */
 START_TEST(test_ns_double_colon) {
   const char *text = "<foo:e xmlns:foo='http://example.org/' foo:a:b='bar' />";
-
-  expect_failure(text, XML_ERROR_INVALID_TOKEN,
-                 "Double colon in attribute name not faulted");
+  const enum XML_Status status
+      = _XML_Parse_SINGLE_BYTES(g_parser, text, (int)strlen(text), XML_TRUE);
+#ifdef XML_NS
+  if ((status == XML_STATUS_OK)
+      || (XML_GetErrorCode(g_parser) != XML_ERROR_INVALID_TOKEN)) {
+    fail("Double colon in attribute name not faulted"
+         " (despite active namespace support)");
+  }
+#else
+  if (status != XML_STATUS_OK) {
+    fail("Double colon in attribute name faulted"
+         " (despite inactive namespace support");
+  }
+#endif
 }
 END_TEST
 
 START_TEST(test_ns_double_colon_element) {
   const char *text = "<foo:bar:e xmlns:foo='http://example.org/' />";
-
-  expect_failure(text, XML_ERROR_INVALID_TOKEN,
-                 "Double colon in element name not faulted");
+  const enum XML_Status status
+      = _XML_Parse_SINGLE_BYTES(g_parser, text, (int)strlen(text), XML_TRUE);
+#ifdef XML_NS
+  if ((status == XML_STATUS_OK)
+      || (XML_GetErrorCode(g_parser) != XML_ERROR_INVALID_TOKEN)) {
+    fail("Double colon in element name not faulted"
+         " (despite active namespace support)");
+  }
+#else
+  if (status != XML_STATUS_OK) {
+    fail("Double colon in element name faulted"
+         " (despite inactive namespace support");
+  }
+#endif
 }
 END_TEST
 
@@ -7329,7 +7352,7 @@ START_TEST(test_misc_version) {
     fail("Version mismatch");
 
 #if ! defined(XML_UNICODE) || defined(XML_UNICODE_WCHAR_T)
-  if (xcstrcmp(version_text, XCS("expat_2.2.9"))) /* needs bump on releases */
+  if (xcstrcmp(version_text, XCS("expat_2.4.3"))) /* needs bump on releases */
     fail("XML_*_VERSION in expat.h out of sync?\n");
 #else
   /* If we have XML_UNICODE defined but not XML_UNICODE_WCHAR_T
@@ -7480,7 +7503,6 @@ START_TEST(test_misc_stop_during_end_handler_issue_240_2) {
 }
 END_TEST
 
-#ifdef XML_DTD
 START_TEST(test_misc_deny_internal_entity_closing_doctype_issue_317) {
   const char *const inputOne = "<!DOCTYPE d [\n"
                                "<!ENTITY % e ']><d/>'>\n"
@@ -7541,7 +7563,6 @@ START_TEST(test_misc_deny_internal_entity_closing_doctype_issue_317) {
   }
 }
 END_TEST
-#endif
 
 static void
 alloc_setup(void) {
@@ -9817,6 +9838,15 @@ START_TEST(test_nsalloc_parse_buffer) {
 
   /* Try a parse before the start of the world */
   /* (Exercises new code path) */
+  if (XML_ParseBuffer(g_parser, 0, XML_FALSE) != XML_STATUS_ERROR)
+    fail("Pre-init XML_ParseBuffer not faulted");
+  if (XML_GetErrorCode(g_parser) != XML_ERROR_NO_BUFFER)
+    fail("Pre-init XML_ParseBuffer faulted for wrong reason");
+
+  buffer = XML_GetBuffer(g_parser, 1 /* any small number greater than 0 */);
+  if (buffer == NULL)
+    fail("Could not acquire parse buffer");
+
   allocation_count = 0;
   if (XML_ParseBuffer(g_parser, 0, XML_FALSE) != XML_STATUS_ERROR)
     fail("Pre-init XML_ParseBuffer not faulted");
@@ -11197,6 +11227,389 @@ START_TEST(test_nsalloc_prefixed_element) {
 }
 END_TEST
 
+#if defined(XML_DTD)
+typedef enum XML_Status (*XmlParseFunction)(XML_Parser, const char *, int, int);
+
+struct AccountingTestCase {
+  const char *primaryText;
+  const char *firstExternalText;  /* often NULL */
+  const char *secondExternalText; /* often NULL */
+  const unsigned long long expectedCountBytesIndirectExtra;
+  XML_Bool singleBytesWanted;
+};
+
+static int
+accounting_external_entity_ref_handler(XML_Parser parser,
+                                       const XML_Char *context,
+                                       const XML_Char *base,
+                                       const XML_Char *systemId,
+                                       const XML_Char *publicId) {
+  UNUSED_P(context);
+  UNUSED_P(base);
+  UNUSED_P(publicId);
+
+  const struct AccountingTestCase *const testCase
+      = (const struct AccountingTestCase *)XML_GetUserData(parser);
+
+  const char *externalText = NULL;
+  if (xcstrcmp(systemId, XCS("first.ent")) == 0) {
+    externalText = testCase->firstExternalText;
+  } else if (xcstrcmp(systemId, XCS("second.ent")) == 0) {
+    externalText = testCase->secondExternalText;
+  } else {
+    assert(! "systemId is neither \"first.ent\" nor \"second.ent\"");
+  }
+  assert(externalText);
+
+  XML_Parser entParser = XML_ExternalEntityParserCreate(parser, context, 0);
+  assert(entParser);
+
+  const XmlParseFunction xmlParseFunction
+      = testCase->singleBytesWanted ? _XML_Parse_SINGLE_BYTES : XML_Parse;
+
+  const enum XML_Status status = xmlParseFunction(
+      entParser, externalText, (int)strlen(externalText), XML_TRUE);
+
+  XML_ParserFree(entParser);
+  return status;
+}
+
+START_TEST(test_accounting_precision) {
+  const XML_Bool filled_later = XML_TRUE; /* value is arbitrary */
+  struct AccountingTestCase cases[] = {
+      {"<e/>", NULL, NULL, 0, 0},
+      {"<e></e>", NULL, NULL, 0, 0},
+
+      /* Attributes */
+      {"<e k1=\"v2\" k2=\"v2\"/>", NULL, NULL, 0, filled_later},
+      {"<e k1=\"v2\" k2=\"v2\"></e>", NULL, NULL, 0, 0},
+      {"<p:e xmlns:p=\"https://domain.invalid/\" />", NULL, NULL, 0,
+       filled_later},
+      {"<e k=\"&amp;&apos;&gt;&lt;&quot;\" />", NULL, NULL,
+       sizeof(XML_Char) * 5 /* number of predefined entites */, filled_later},
+      {"<e1 xmlns='https://example.org/'>\n"
+       "  <e2 xmlns=''/>\n"
+       "</e1>",
+       NULL, NULL, 0, filled_later},
+
+      /* Text */
+      {"<e>text</e>", NULL, NULL, 0, filled_later},
+      {"<e1><e2>text1<e3/>text2</e2></e1>", NULL, NULL, 0, filled_later},
+      {"<e>&amp;&apos;&gt;&lt;&quot;</e>", NULL, NULL,
+       sizeof(XML_Char) * 5 /* number of predefined entites */, filled_later},
+      {"<e>&#65;&#41;</e>", NULL, NULL, 0, filled_later},
+
+      /* Prolog */
+      {"<?xml version=\"1.0\"?><root/>", NULL, NULL, 0, filled_later},
+
+      /* Whitespace */
+      {"  <e1>  <e2>  </e2>  </e1>  ", NULL, NULL, 0, filled_later},
+      {"<e1  ><e2  /></e1  >", NULL, NULL, 0, filled_later},
+      {"<e1><e2 k = \"v\"/><e3 k = 'v'/></e1>", NULL, NULL, 0, filled_later},
+
+      /* Comments */
+      {"<!-- Comment --><e><!-- Comment --></e>", NULL, NULL, 0, filled_later},
+
+      /* Processing instructions */
+      {"<?xml-stylesheet type=\"text/xsl\" href=\"https://domain.invalid/\" media=\"all\"?><e/>",
+       NULL, NULL, 0, filled_later},
+      {"<?pi0?><?pi1 ?><?pi2  ?><!DOCTYPE r SYSTEM 'first.ent'><r/>",
+       "<?pi3?><!ENTITY % e1 SYSTEM 'second.ent'><?pi4?>%e1;<?pi5?>", "<?pi6?>",
+       0, filled_later},
+
+      /* CDATA */
+      {"<e><![CDATA[one two three]]></e>", NULL, NULL, 0, filled_later},
+      /* The following is the essence of this OSS-Fuzz finding:
+         https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=34302
+         https://oss-fuzz.com/testcase-detail/4860575394955264
+      */
+      {"<!DOCTYPE r [\n"
+       "<!ENTITY e \"111<![CDATA[2 <= 2]]>333\">\n"
+       "]>\n"
+       "<r>&e;</r>\n",
+       NULL, NULL, sizeof(XML_Char) * strlen("111<![CDATA[2 <= 2]]>333"),
+       filled_later},
+
+      /* Conditional sections */
+      {"<!DOCTYPE r [\n"
+       "<!ENTITY % draft 'INCLUDE'>\n"
+       "<!ENTITY % final 'IGNORE'>\n"
+       "<!ENTITY % import SYSTEM \"first.ent\">\n"
+       "%import;\n"
+       "]>\n"
+       "<r/>\n",
+       "<![%draft;[<!--1-->]]>\n"
+       "<![%final;[<!--22-->]]>",
+       NULL, sizeof(XML_Char) * (strlen("INCLUDE") + strlen("IGNORE")),
+       filled_later},
+
+      /* General entities */
+      {"<!DOCTYPE root [\n"
+       "<!ENTITY nine \"123456789\">\n"
+       "]>\n"
+       "<root>&nine;</root>",
+       NULL, NULL, sizeof(XML_Char) * strlen("123456789"), filled_later},
+      {"<!DOCTYPE root [\n"
+       "<!ENTITY nine \"123456789\">\n"
+       "]>\n"
+       "<root k1=\"&nine;\"/>",
+       NULL, NULL, sizeof(XML_Char) * strlen("123456789"), filled_later},
+      {"<!DOCTYPE root [\n"
+       "<!ENTITY nine \"123456789\">\n"
+       "<!ENTITY nine2 \"&nine;&nine;\">\n"
+       "]>\n"
+       "<root>&nine2;&nine2;&nine2;</root>",
+       NULL, NULL,
+       sizeof(XML_Char) * 3 /* calls to &nine2; */ * 2 /* calls to &nine; */
+           * (strlen("&nine;") + strlen("123456789")),
+       filled_later},
+      {"<!DOCTYPE r [\n"
+       "  <!ENTITY five SYSTEM 'first.ent'>\n"
+       "]>\n"
+       "<r>&five;</r>",
+       "12345", NULL, 0, filled_later},
+
+      /* Parameter entities */
+      {"<!DOCTYPE r [\n"
+       "<!ENTITY % comment \"<!---->\">\n"
+       "%comment;\n"
+       "]>\n"
+       "<r/>",
+       NULL, NULL, sizeof(XML_Char) * strlen("<!---->"), filled_later},
+      {"<!DOCTYPE r [\n"
+       "<!ENTITY % ninedef \"&#60;!ENTITY nine &#34;123456789&#34;&#62;\">\n"
+       "%ninedef;\n"
+       "]>\n"
+       "<r>&nine;</r>",
+       NULL, NULL,
+       sizeof(XML_Char)
+           * (strlen("<!ENTITY nine \"123456789\">") + strlen("123456789")),
+       filled_later},
+      {"<!DOCTYPE r [\n"
+       "<!ENTITY % comment \"<!--1-->\">\n"
+       "<!ENTITY % comment2 \"&#37;comment;<!--22-->&#37;comment;\">\n"
+       "%comment2;\n"
+       "]>\n"
+       "<r/>\n",
+       NULL, NULL,
+       sizeof(XML_Char)
+           * (strlen("%comment;<!--22-->%comment;") + 2 * strlen("<!--1-->")),
+       filled_later},
+      {"<!DOCTYPE r [\n"
+       "  <!ENTITY % five \"12345\">\n"
+       "  <!ENTITY % five2def \"&#60;!ENTITY five2 &#34;[&#37;five;][&#37;five;]]]]&#34;&#62;\">\n"
+       "  %five2def;\n"
+       "]>\n"
+       "<r>&five2;</r>",
+       NULL, NULL, /* from "%five2def;": */
+       sizeof(XML_Char)
+           * (strlen("<!ENTITY five2 \"[%five;][%five;]]]]\">")
+              + 2 /* calls to "%five;" */ * strlen("12345")
+              + /* from "&five2;": */ strlen("[12345][12345]]]]")),
+       filled_later},
+      {"<!DOCTYPE r SYSTEM \"first.ent\">\n"
+       "<r/>",
+       "<!ENTITY % comment '<!--1-->'>\n"
+       "<!ENTITY % comment2 '<!--22-->%comment;<!--22-->%comment;<!--22-->'>\n"
+       "%comment2;",
+       NULL,
+       sizeof(XML_Char)
+           * (strlen("<!--22-->%comment;<!--22-->%comment;<!--22-->")
+              + 2 /* calls to "%comment;" */ * strlen("<!---->")),
+       filled_later},
+      {"<!DOCTYPE r SYSTEM 'first.ent'>\n"
+       "<r/>",
+       "<!ENTITY % e1 PUBLIC 'foo' 'second.ent'>\n"
+       "<!ENTITY % e2 '<!--22-->%e1;<!--22-->'>\n"
+       "%e2;\n",
+       "<!--1-->", sizeof(XML_Char) * strlen("<!--22--><!--1--><!--22-->"),
+       filled_later},
+      {
+          "<!DOCTYPE r SYSTEM 'first.ent'>\n"
+          "<r/>",
+          "<!ENTITY % e1 SYSTEM 'second.ent'>\n"
+          "<!ENTITY % e2 '%e1;'>",
+          "<?xml version='1.0' encoding='utf-8'?>\n"
+          "hello\n"
+          "xml" /* without trailing newline! */,
+          0,
+          filled_later,
+      },
+      {
+          "<!DOCTYPE r SYSTEM 'first.ent'>\n"
+          "<r/>",
+          "<!ENTITY % e1 SYSTEM 'second.ent'>\n"
+          "<!ENTITY % e2 '%e1;'>",
+          "<?xml version='1.0' encoding='utf-8'?>\n"
+          "hello\n"
+          "xml\n" /* with trailing newline! */,
+          0,
+          filled_later,
+      },
+      {"<!DOCTYPE doc SYSTEM 'first.ent'>\n"
+       "<doc></doc>\n",
+       "<!ELEMENT doc EMPTY>\n"
+       "<!ENTITY % e1 SYSTEM 'second.ent'>\n"
+       "<!ENTITY % e2 '%e1;'>\n"
+       "%e1;\n",
+       "\xEF\xBB\xBF<!ATTLIST doc a1 CDATA 'value'>" /* UTF-8 BOM */,
+       strlen("\xEF\xBB\xBF<!ATTLIST doc a1 CDATA 'value'>"), filled_later},
+      {"<!DOCTYPE r [\n"
+       "  <!ENTITY five SYSTEM 'first.ent'>\n"
+       "]>\n"
+       "<r>&five;</r>",
+       "\xEF\xBB\xBF" /* UTF-8 BOM */, NULL, 0, filled_later},
+  };
+
+  const size_t countCases = sizeof(cases) / sizeof(cases[0]);
+  size_t u = 0;
+  for (; u < countCases; u++) {
+    size_t v = 0;
+    for (; v < 2; v++) {
+      const XML_Bool singleBytesWanted = (v == 0) ? XML_FALSE : XML_TRUE;
+      const unsigned long long expectedCountBytesDirect
+          = strlen(cases[u].primaryText);
+      const unsigned long long expectedCountBytesIndirect
+          = (cases[u].firstExternalText ? strlen(cases[u].firstExternalText)
+                                        : 0)
+            + (cases[u].secondExternalText ? strlen(cases[u].secondExternalText)
+                                           : 0)
+            + cases[u].expectedCountBytesIndirectExtra;
+
+      XML_Parser parser = XML_ParserCreate(NULL);
+      XML_SetParamEntityParsing(parser, XML_PARAM_ENTITY_PARSING_ALWAYS);
+      if (cases[u].firstExternalText) {
+        XML_SetExternalEntityRefHandler(parser,
+                                        accounting_external_entity_ref_handler);
+        XML_SetUserData(parser, (void *)&cases[u]);
+        cases[u].singleBytesWanted = singleBytesWanted;
+      }
+
+      const XmlParseFunction xmlParseFunction
+          = singleBytesWanted ? _XML_Parse_SINGLE_BYTES : XML_Parse;
+
+      enum XML_Status status
+          = xmlParseFunction(parser, cases[u].primaryText,
+                             (int)strlen(cases[u].primaryText), XML_TRUE);
+      if (status != XML_STATUS_OK) {
+        _xml_failure(parser, __FILE__, __LINE__);
+      }
+
+      const unsigned long long actualCountBytesDirect
+          = testingAccountingGetCountBytesDirect(parser);
+      const unsigned long long actualCountBytesIndirect
+          = testingAccountingGetCountBytesIndirect(parser);
+
+      XML_ParserFree(parser);
+
+      if (actualCountBytesDirect != expectedCountBytesDirect) {
+        fprintf(
+            stderr,
+            "Document " EXPAT_FMT_SIZE_T("") " of " EXPAT_FMT_SIZE_T("") ", %s: Expected " EXPAT_FMT_ULL(
+                "") " count direct bytes, got " EXPAT_FMT_ULL("") " instead.\n",
+            u + 1, countCases, singleBytesWanted ? "single bytes" : "chunks",
+            expectedCountBytesDirect, actualCountBytesDirect);
+        fail("Count of direct bytes is off");
+      }
+
+      if (actualCountBytesIndirect != expectedCountBytesIndirect) {
+        fprintf(
+            stderr,
+            "Document " EXPAT_FMT_SIZE_T("") " of " EXPAT_FMT_SIZE_T("") ", %s: Expected " EXPAT_FMT_ULL(
+                "") " count indirect bytes, got " EXPAT_FMT_ULL("") " instead.\n",
+            u + 1, countCases, singleBytesWanted ? "single bytes" : "chunks",
+            expectedCountBytesIndirect, actualCountBytesIndirect);
+        fail("Count of indirect bytes is off");
+      }
+    }
+  }
+}
+END_TEST
+
+START_TEST(test_billion_laughs_attack_protection_api) {
+  XML_Parser parserWithoutParent = XML_ParserCreate(NULL);
+  XML_Parser parserWithParent
+      = XML_ExternalEntityParserCreate(parserWithoutParent, NULL, NULL);
+  if (parserWithoutParent == NULL)
+    fail("parserWithoutParent is NULL");
+  if (parserWithParent == NULL)
+    fail("parserWithParent is NULL");
+
+  // XML_SetBillionLaughsAttackProtectionMaximumAmplification, error cases
+  if (XML_SetBillionLaughsAttackProtectionMaximumAmplification(NULL, 123.0f)
+      == XML_TRUE)
+    fail("Call with NULL parser is NOT supposed to succeed");
+  if (XML_SetBillionLaughsAttackProtectionMaximumAmplification(parserWithParent,
+                                                               123.0f)
+      == XML_TRUE)
+    fail("Call with non-root parser is NOT supposed to succeed");
+  if (XML_SetBillionLaughsAttackProtectionMaximumAmplification(
+          parserWithoutParent, NAN)
+      == XML_TRUE)
+    fail("Call with NaN limit is NOT supposed to succeed");
+  if (XML_SetBillionLaughsAttackProtectionMaximumAmplification(
+          parserWithoutParent, -1.0f)
+      == XML_TRUE)
+    fail("Call with negative limit is NOT supposed to succeed");
+  if (XML_SetBillionLaughsAttackProtectionMaximumAmplification(
+          parserWithoutParent, 0.9f)
+      == XML_TRUE)
+    fail("Call with positive limit <1.0 is NOT supposed to succeed");
+
+  // XML_SetBillionLaughsAttackProtectionMaximumAmplification, success cases
+  if (XML_SetBillionLaughsAttackProtectionMaximumAmplification(
+          parserWithoutParent, 1.0f)
+      == XML_FALSE)
+    fail("Call with positive limit >=1.0 is supposed to succeed");
+  if (XML_SetBillionLaughsAttackProtectionMaximumAmplification(
+          parserWithoutParent, 123456.789f)
+      == XML_FALSE)
+    fail("Call with positive limit >=1.0 is supposed to succeed");
+  if (XML_SetBillionLaughsAttackProtectionMaximumAmplification(
+          parserWithoutParent, INFINITY)
+      == XML_FALSE)
+    fail("Call with positive limit >=1.0 is supposed to succeed");
+
+  // XML_SetBillionLaughsAttackProtectionActivationThreshold, error cases
+  if (XML_SetBillionLaughsAttackProtectionActivationThreshold(NULL, 123)
+      == XML_TRUE)
+    fail("Call with NULL parser is NOT supposed to succeed");
+  if (XML_SetBillionLaughsAttackProtectionActivationThreshold(parserWithParent,
+                                                              123)
+      == XML_TRUE)
+    fail("Call with non-root parser is NOT supposed to succeed");
+
+  // XML_SetBillionLaughsAttackProtectionActivationThreshold, success cases
+  if (XML_SetBillionLaughsAttackProtectionActivationThreshold(
+          parserWithoutParent, 123)
+      == XML_FALSE)
+    fail("Call with non-NULL parentless parser is supposed to succeed");
+
+  XML_ParserFree(parserWithParent);
+  XML_ParserFree(parserWithoutParent);
+}
+END_TEST
+
+START_TEST(test_helper_unsigned_char_to_printable) {
+  // Smoke test
+  unsigned char uc = 0;
+  for (; uc < (unsigned char)-1; uc++) {
+    const char *const printable = unsignedCharToPrintable(uc);
+    if (printable == NULL)
+      fail("unsignedCharToPrintable returned NULL");
+    if (strlen(printable) < (size_t)1)
+      fail("unsignedCharToPrintable returned empty string");
+  }
+
+  // Two concrete samples
+  if (strcmp(unsignedCharToPrintable('A'), "A") != 0)
+    fail("unsignedCharToPrintable result mistaken");
+  if (strcmp(unsignedCharToPrintable('\\'), "\\\\") != 0)
+    fail("unsignedCharToPrintable result mistaken");
+}
+END_TEST
+#endif // defined(XML_DTD)
+
 static Suite *
 make_suite(void) {
   Suite *s = suite_create("basic");
@@ -11205,6 +11618,9 @@ make_suite(void) {
   TCase *tc_misc = tcase_create("miscellaneous tests");
   TCase *tc_alloc = tcase_create("allocation tests");
   TCase *tc_nsalloc = tcase_create("namespace allocation tests");
+#if defined(XML_DTD)
+  TCase *tc_accounting = tcase_create("accounting tests");
+#endif
 
   suite_add_tcase(s, tc_basic);
   tcase_add_checked_fixture(tc_basic, basic_setup, basic_teardown);
@@ -11259,13 +11675,14 @@ make_suite(void) {
                  test_wfc_undeclared_entity_with_external_subset_standalone);
   tcase_add_test(tc_basic, test_entity_with_external_subset_unless_standalone);
   tcase_add_test(tc_basic, test_wfc_no_recursive_entity_refs);
-  tcase_add_test(tc_basic, test_ext_entity_set_encoding);
-  tcase_add_test(tc_basic, test_ext_entity_no_handler);
-  tcase_add_test(tc_basic, test_ext_entity_set_bom);
-  tcase_add_test(tc_basic, test_ext_entity_bad_encoding);
-  tcase_add_test(tc_basic, test_ext_entity_bad_encoding_2);
-  tcase_add_test(tc_basic, test_ext_entity_invalid_parse);
-  tcase_add_test(tc_basic, test_ext_entity_invalid_suspended_parse);
+  tcase_add_test__ifdef_xml_dtd(tc_basic, test_ext_entity_set_encoding);
+  tcase_add_test__ifdef_xml_dtd(tc_basic, test_ext_entity_no_handler);
+  tcase_add_test__ifdef_xml_dtd(tc_basic, test_ext_entity_set_bom);
+  tcase_add_test__ifdef_xml_dtd(tc_basic, test_ext_entity_bad_encoding);
+  tcase_add_test__ifdef_xml_dtd(tc_basic, test_ext_entity_bad_encoding_2);
+  tcase_add_test__ifdef_xml_dtd(tc_basic, test_ext_entity_invalid_parse);
+  tcase_add_test__ifdef_xml_dtd(tc_basic,
+                                test_ext_entity_invalid_suspended_parse);
   tcase_add_test(tc_basic, test_dtd_default_handling);
   tcase_add_test(tc_basic, test_dtd_attr_handling);
   tcase_add_test(tc_basic, test_empty_ns_without_namespaces);
@@ -11277,25 +11694,22 @@ make_suite(void) {
   tcase_add_test(tc_basic, test_good_cdata_utf16);
   tcase_add_test(tc_basic, test_good_cdata_utf16_le);
   tcase_add_test(tc_basic, test_long_cdata_utf16);
-#ifndef XML_MIN_SIZE /* FIXME workaround -DXML_MIN_SIZE + ASan (issue #332) */
   tcase_add_test(tc_basic, test_multichar_cdata_utf16);
-#endif
   tcase_add_test(tc_basic, test_utf16_bad_surrogate_pair);
   tcase_add_test(tc_basic, test_bad_cdata);
-#ifndef XML_MIN_SIZE /* FIXME workaround -DXML_MIN_SIZE + ASan (issue #332) */
   tcase_add_test(tc_basic, test_bad_cdata_utf16);
-#endif
   tcase_add_test(tc_basic, test_stop_parser_between_cdata_calls);
   tcase_add_test(tc_basic, test_suspend_parser_between_cdata_calls);
   tcase_add_test(tc_basic, test_memory_allocation);
   tcase_add_test(tc_basic, test_default_current);
   tcase_add_test(tc_basic, test_dtd_elements);
-  tcase_add_test(tc_basic, test_set_foreign_dtd);
-  tcase_add_test(tc_basic, test_foreign_dtd_not_standalone);
-  tcase_add_test(tc_basic, test_invalid_foreign_dtd);
-  tcase_add_test(tc_basic, test_foreign_dtd_with_doctype);
-  tcase_add_test(tc_basic, test_foreign_dtd_without_external_subset);
-  tcase_add_test(tc_basic, test_empty_foreign_dtd);
+  tcase_add_test__ifdef_xml_dtd(tc_basic, test_set_foreign_dtd);
+  tcase_add_test__ifdef_xml_dtd(tc_basic, test_foreign_dtd_not_standalone);
+  tcase_add_test__ifdef_xml_dtd(tc_basic, test_invalid_foreign_dtd);
+  tcase_add_test__ifdef_xml_dtd(tc_basic, test_foreign_dtd_with_doctype);
+  tcase_add_test__ifdef_xml_dtd(tc_basic,
+                                test_foreign_dtd_without_external_subset);
+  tcase_add_test__ifdef_xml_dtd(tc_basic, test_empty_foreign_dtd);
   tcase_add_test(tc_basic, test_set_base);
   tcase_add_test(tc_basic, test_attributes);
   tcase_add_test(tc_basic, test_reset_in_entity);
@@ -11312,8 +11726,8 @@ make_suite(void) {
   tcase_add_test(tc_basic, test_trailing_rsqb);
   tcase_add_test(tc_basic, test_ext_entity_trailing_rsqb);
   tcase_add_test(tc_basic, test_ext_entity_good_cdata);
-  tcase_add_test(tc_basic, test_user_parameters);
-  tcase_add_test(tc_basic, test_ext_entity_ref_parameter);
+  tcase_add_test__ifdef_xml_dtd(tc_basic, test_user_parameters);
+  tcase_add_test__ifdef_xml_dtd(tc_basic, test_ext_entity_ref_parameter);
   tcase_add_test(tc_basic, test_empty_parse);
   tcase_add_test(tc_basic, test_get_buffer_1);
   tcase_add_test(tc_basic, test_get_buffer_2);
@@ -11321,25 +11735,26 @@ make_suite(void) {
   tcase_add_test(tc_basic, test_byte_info_at_error);
   tcase_add_test(tc_basic, test_byte_info_at_cdata);
   tcase_add_test(tc_basic, test_predefined_entities);
-  tcase_add_test(tc_basic, test_invalid_tag_in_dtd);
+  tcase_add_test__ifdef_xml_dtd(tc_basic, test_invalid_tag_in_dtd);
   tcase_add_test(tc_basic, test_not_predefined_entities);
-  tcase_add_test(tc_basic, test_ignore_section);
-  tcase_add_test(tc_basic, test_ignore_section_utf16);
-  tcase_add_test(tc_basic, test_ignore_section_utf16_be);
-  tcase_add_test(tc_basic, test_bad_ignore_section);
-  tcase_add_test(tc_basic, test_external_entity_values);
-  tcase_add_test(tc_basic, test_ext_entity_not_standalone);
-  tcase_add_test(tc_basic, test_ext_entity_value_abort);
+  tcase_add_test__ifdef_xml_dtd(tc_basic, test_ignore_section);
+  tcase_add_test__ifdef_xml_dtd(tc_basic, test_ignore_section_utf16);
+  tcase_add_test__ifdef_xml_dtd(tc_basic, test_ignore_section_utf16_be);
+  tcase_add_test__ifdef_xml_dtd(tc_basic, test_bad_ignore_section);
+  tcase_add_test__ifdef_xml_dtd(tc_basic, test_external_entity_values);
+  tcase_add_test__ifdef_xml_dtd(tc_basic, test_ext_entity_not_standalone);
+  tcase_add_test__ifdef_xml_dtd(tc_basic, test_ext_entity_value_abort);
   tcase_add_test(tc_basic, test_bad_public_doctype);
   tcase_add_test(tc_basic, test_attribute_enum_value);
   tcase_add_test(tc_basic, test_predefined_entity_redefinition);
-  tcase_add_test(tc_basic, test_dtd_stop_processing);
+  tcase_add_test__ifdef_xml_dtd(tc_basic, test_dtd_stop_processing);
   tcase_add_test(tc_basic, test_public_notation_no_sysid);
   tcase_add_test(tc_basic, test_nested_groups);
   tcase_add_test(tc_basic, test_group_choice);
   tcase_add_test(tc_basic, test_standalone_parameter_entity);
-  tcase_add_test(tc_basic, test_skipped_parameter_entity);
-  tcase_add_test(tc_basic, test_recursive_external_parameter_entity);
+  tcase_add_test__ifdef_xml_dtd(tc_basic, test_skipped_parameter_entity);
+  tcase_add_test__ifdef_xml_dtd(tc_basic,
+                                test_recursive_external_parameter_entity);
   tcase_add_test(tc_basic, test_undefined_ext_entity_in_external_dtd);
   tcase_add_test(tc_basic, test_suspend_xdecl);
   tcase_add_test(tc_basic, test_abort_epilog);
@@ -11349,9 +11764,9 @@ make_suite(void) {
   tcase_add_test(tc_basic, test_unfinished_epilog);
   tcase_add_test(tc_basic, test_partial_char_in_epilog);
   tcase_add_test(tc_basic, test_hash_collision);
-  tcase_add_test(tc_basic, test_suspend_resume_internal_entity);
-  tcase_add_test(tc_basic, test_resume_entity_with_syntax_error);
-  tcase_add_test(tc_basic, test_suspend_resume_parameter_entity);
+  tcase_add_test__ifdef_xml_dtd(tc_basic, test_suspend_resume_internal_entity);
+  tcase_add_test__ifdef_xml_dtd(tc_basic, test_resume_entity_with_syntax_error);
+  tcase_add_test__ifdef_xml_dtd(tc_basic, test_suspend_resume_parameter_entity);
   tcase_add_test(tc_basic, test_restart_on_error);
   tcase_add_test(tc_basic, test_reject_lt_in_attribute_value);
   tcase_add_test(tc_basic, test_reject_unfinished_param_in_att_value);
@@ -11360,7 +11775,7 @@ make_suite(void) {
   tcase_add_test(tc_basic, test_skipped_external_entity);
   tcase_add_test(tc_basic, test_skipped_null_loaded_ext_entity);
   tcase_add_test(tc_basic, test_skipped_unloaded_ext_entity);
-  tcase_add_test(tc_basic, test_param_entity_with_trailing_cr);
+  tcase_add_test__ifdef_xml_dtd(tc_basic, test_param_entity_with_trailing_cr);
   tcase_add_test(tc_basic, test_invalid_character_entity);
   tcase_add_test(tc_basic, test_invalid_character_entity_2);
   tcase_add_test(tc_basic, test_invalid_character_entity_3);
@@ -11403,7 +11818,7 @@ make_suite(void) {
   tcase_add_test(tc_basic, test_utf16_attribute);
   tcase_add_test(tc_basic, test_utf16_second_attr);
   tcase_add_test(tc_basic, test_attr_after_solidus);
-  tcase_add_test(tc_basic, test_utf16_pe);
+  tcase_add_test__ifdef_xml_dtd(tc_basic, test_utf16_pe);
   tcase_add_test(tc_basic, test_bad_attr_desc_keyword);
   tcase_add_test(tc_basic, test_bad_attr_desc_keyword_utf16);
   tcase_add_test(tc_basic, test_bad_doctype);
@@ -11411,11 +11826,11 @@ make_suite(void) {
   tcase_add_test(tc_basic, test_bad_doctype_plus);
   tcase_add_test(tc_basic, test_bad_doctype_star);
   tcase_add_test(tc_basic, test_bad_doctype_query);
-  tcase_add_test(tc_basic, test_unknown_encoding_bad_ignore);
+  tcase_add_test__ifdef_xml_dtd(tc_basic, test_unknown_encoding_bad_ignore);
   tcase_add_test(tc_basic, test_entity_in_utf16_be_attr);
   tcase_add_test(tc_basic, test_entity_in_utf16_le_attr);
-  tcase_add_test(tc_basic, test_entity_public_utf16_be);
-  tcase_add_test(tc_basic, test_entity_public_utf16_le);
+  tcase_add_test__ifdef_xml_dtd(tc_basic, test_entity_public_utf16_be);
+  tcase_add_test__ifdef_xml_dtd(tc_basic, test_entity_public_utf16_le);
   tcase_add_test(tc_basic, test_short_doctype);
   tcase_add_test(tc_basic, test_short_doctype_2);
   tcase_add_test(tc_basic, test_short_doctype_3);
@@ -11434,7 +11849,8 @@ make_suite(void) {
   tcase_add_test(tc_namespace, test_ns_tagname_overwrite);
   tcase_add_test(tc_namespace, test_ns_tagname_overwrite_triplet);
   tcase_add_test(tc_namespace, test_start_ns_clears_start_element);
-  tcase_add_test(tc_namespace, test_default_ns_from_ext_subset_and_ext_ge);
+  tcase_add_test__ifdef_xml_dtd(tc_namespace,
+                                test_default_ns_from_ext_subset_and_ext_ge);
   tcase_add_test(tc_namespace, test_ns_prefix_with_empty_uri_1);
   tcase_add_test(tc_namespace, test_ns_prefix_with_empty_uri_2);
   tcase_add_test(tc_namespace, test_ns_prefix_with_empty_uri_3);
@@ -11475,10 +11891,8 @@ make_suite(void) {
   tcase_add_test(tc_misc, test_misc_utf16le);
   tcase_add_test(tc_misc, test_misc_stop_during_end_handler_issue_240_1);
   tcase_add_test(tc_misc, test_misc_stop_during_end_handler_issue_240_2);
-#ifdef XML_DTD
-  tcase_add_test(tc_misc,
-                 test_misc_deny_internal_entity_closing_doctype_issue_317);
-#endif
+  tcase_add_test__ifdef_xml_dtd(
+      tc_misc, test_misc_deny_internal_entity_closing_doctype_issue_317);
 
   suite_add_tcase(s, tc_alloc);
   tcase_add_checked_fixture(tc_alloc, alloc_setup, alloc_teardown);
@@ -11489,45 +11903,49 @@ make_suite(void) {
   tcase_add_test(tc_alloc, test_alloc_parse_pi_3);
   tcase_add_test(tc_alloc, test_alloc_parse_comment);
   tcase_add_test(tc_alloc, test_alloc_parse_comment_2);
-  tcase_add_test(tc_alloc, test_alloc_create_external_parser);
-  tcase_add_test(tc_alloc, test_alloc_run_external_parser);
-  tcase_add_test(tc_alloc, test_alloc_dtd_copy_default_atts);
-  tcase_add_test(tc_alloc, test_alloc_external_entity);
-  tcase_add_test(tc_alloc, test_alloc_ext_entity_set_encoding);
-  tcase_add_test(tc_alloc, test_alloc_internal_entity);
-  tcase_add_test(tc_alloc, test_alloc_dtd_default_handling);
+  tcase_add_test__ifdef_xml_dtd(tc_alloc, test_alloc_create_external_parser);
+  tcase_add_test__ifdef_xml_dtd(tc_alloc, test_alloc_run_external_parser);
+  tcase_add_test__ifdef_xml_dtd(tc_alloc, test_alloc_dtd_copy_default_atts);
+  tcase_add_test__ifdef_xml_dtd(tc_alloc, test_alloc_external_entity);
+  tcase_add_test__ifdef_xml_dtd(tc_alloc, test_alloc_ext_entity_set_encoding);
+  tcase_add_test__ifdef_xml_dtd(tc_alloc, test_alloc_internal_entity);
+  tcase_add_test__ifdef_xml_dtd(tc_alloc, test_alloc_dtd_default_handling);
   tcase_add_test(tc_alloc, test_alloc_explicit_encoding);
   tcase_add_test(tc_alloc, test_alloc_set_base);
   tcase_add_test(tc_alloc, test_alloc_realloc_buffer);
   tcase_add_test(tc_alloc, test_alloc_ext_entity_realloc_buffer);
   tcase_add_test(tc_alloc, test_alloc_realloc_many_attributes);
-  tcase_add_test(tc_alloc, test_alloc_public_entity_value);
-  tcase_add_test(tc_alloc, test_alloc_realloc_subst_public_entity_value);
+  tcase_add_test__ifdef_xml_dtd(tc_alloc, test_alloc_public_entity_value);
+  tcase_add_test__ifdef_xml_dtd(tc_alloc,
+                                test_alloc_realloc_subst_public_entity_value);
   tcase_add_test(tc_alloc, test_alloc_parse_public_doctype);
   tcase_add_test(tc_alloc, test_alloc_parse_public_doctype_long_name);
-  tcase_add_test(tc_alloc, test_alloc_set_foreign_dtd);
-  tcase_add_test(tc_alloc, test_alloc_attribute_enum_value);
-  tcase_add_test(tc_alloc, test_alloc_realloc_attribute_enum_value);
-  tcase_add_test(tc_alloc, test_alloc_realloc_implied_attribute);
-  tcase_add_test(tc_alloc, test_alloc_realloc_default_attribute);
+  tcase_add_test__ifdef_xml_dtd(tc_alloc, test_alloc_set_foreign_dtd);
+  tcase_add_test__ifdef_xml_dtd(tc_alloc, test_alloc_attribute_enum_value);
+  tcase_add_test__ifdef_xml_dtd(tc_alloc,
+                                test_alloc_realloc_attribute_enum_value);
+  tcase_add_test__ifdef_xml_dtd(tc_alloc, test_alloc_realloc_implied_attribute);
+  tcase_add_test__ifdef_xml_dtd(tc_alloc, test_alloc_realloc_default_attribute);
   tcase_add_test(tc_alloc, test_alloc_notation);
   tcase_add_test(tc_alloc, test_alloc_public_notation);
   tcase_add_test(tc_alloc, test_alloc_system_notation);
-  tcase_add_test(tc_alloc, test_alloc_nested_groups);
-  tcase_add_test(tc_alloc, test_alloc_realloc_nested_groups);
+  tcase_add_test__ifdef_xml_dtd(tc_alloc, test_alloc_nested_groups);
+  tcase_add_test__ifdef_xml_dtd(tc_alloc, test_alloc_realloc_nested_groups);
   tcase_add_test(tc_alloc, test_alloc_large_group);
-  tcase_add_test(tc_alloc, test_alloc_realloc_group_choice);
+  tcase_add_test__ifdef_xml_dtd(tc_alloc, test_alloc_realloc_group_choice);
   tcase_add_test(tc_alloc, test_alloc_pi_in_epilog);
   tcase_add_test(tc_alloc, test_alloc_comment_in_epilog);
-  tcase_add_test(tc_alloc, test_alloc_realloc_long_attribute_value);
+  tcase_add_test__ifdef_xml_dtd(tc_alloc,
+                                test_alloc_realloc_long_attribute_value);
   tcase_add_test(tc_alloc, test_alloc_attribute_whitespace);
   tcase_add_test(tc_alloc, test_alloc_attribute_predefined_entity);
   tcase_add_test(tc_alloc, test_alloc_long_attr_default_with_char_ref);
   tcase_add_test(tc_alloc, test_alloc_long_attr_value);
-  tcase_add_test(tc_alloc, test_alloc_nested_entities);
-  tcase_add_test(tc_alloc, test_alloc_realloc_param_entity_newline);
-  tcase_add_test(tc_alloc, test_alloc_realloc_ce_extends_pe);
-  tcase_add_test(tc_alloc, test_alloc_realloc_attributes);
+  tcase_add_test__ifdef_xml_dtd(tc_alloc, test_alloc_nested_entities);
+  tcase_add_test__ifdef_xml_dtd(tc_alloc,
+                                test_alloc_realloc_param_entity_newline);
+  tcase_add_test__ifdef_xml_dtd(tc_alloc, test_alloc_realloc_ce_extends_pe);
+  tcase_add_test__ifdef_xml_dtd(tc_alloc, test_alloc_realloc_attributes);
   tcase_add_test(tc_alloc, test_alloc_long_doc_name);
   tcase_add_test(tc_alloc, test_alloc_long_base);
   tcase_add_test(tc_alloc, test_alloc_long_public_id);
@@ -11563,6 +11981,13 @@ make_suite(void) {
   tcase_add_test(tc_nsalloc, test_nsalloc_long_systemid_in_ext);
   tcase_add_test(tc_nsalloc, test_nsalloc_prefixed_element);
 
+#if defined(XML_DTD)
+  suite_add_tcase(s, tc_accounting);
+  tcase_add_test(tc_accounting, test_accounting_precision);
+  tcase_add_test(tc_accounting, test_billion_laughs_attack_protection_api);
+  tcase_add_test(tc_accounting, test_helper_unsigned_char_to_printable);
+#endif
+
   return s;
 }
 
diff --git a/contrib/expat/tests/runtests.sln b/contrib/expat/tests/runtests.sln
deleted file mode 100644
index 6e07293f580c..000000000000
--- a/contrib/expat/tests/runtests.sln
+++ /dev/null
@@ -1,24 +0,0 @@
-
-Microsoft Visual Studio Solution File, Format Version 12.00
-# Visual Studio 2013
-VisualStudioVersion = 12.0.40629.0
-MinimumVisualStudioVersion = 10.0.40219.1
-Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "runtests", "runtests.vcxproj", "{63D6D820-B526-4A5F-9605-9B8551FAC591}"
-EndProject
-Global
-	GlobalSection(SolutionConfigurationPlatforms) = preSolution
-		Debug|Win32 = Debug|Win32
-		Release|Win32 = Release|Win32
-		Template|Win32 = Template|Win32
-	EndGlobalSection
-	GlobalSection(ProjectConfigurationPlatforms) = postSolution
-		{63D6D820-B526-4A5F-9605-9B8551FAC591}.Debug|Win32.ActiveCfg = Debug|Win32
-		{63D6D820-B526-4A5F-9605-9B8551FAC591}.Debug|Win32.Build.0 = Debug|Win32
-		{63D6D820-B526-4A5F-9605-9B8551FAC591}.Release|Win32.ActiveCfg = Release|Win32
-		{63D6D820-B526-4A5F-9605-9B8551FAC591}.Release|Win32.Build.0 = Release|Win32
-		{63D6D820-B526-4A5F-9605-9B8551FAC591}.Template|Win32.ActiveCfg = Release|Win32
-	EndGlobalSection
-	GlobalSection(SolutionProperties) = preSolution
-		HideSolutionNode = FALSE
-	EndGlobalSection
-EndGlobal
diff --git a/contrib/expat/tests/runtestspp.cpp b/contrib/expat/tests/runtestspp.cpp
index fd3ceaa97a39..52f530529ea1 100644
--- a/contrib/expat/tests/runtestspp.cpp
+++ b/contrib/expat/tests/runtestspp.cpp
@@ -9,8 +9,8 @@
                         \___/_/\_\ .__/ \__,_|\__|
                                  |_| XML parser
 
-   Copyright (c) 1997-2000 Thai Open Source Software Center Ltd
-   Copyright (c) 2000-2017 Expat development team
+   Copyright (c) 2005 Fred L. Drake, Jr. <fdrake@users.sourceforge.net>
+   Copyright (c) 2017 Sebastian Pipping <sebastian@pipping.org>
    Licensed under the MIT license:
 
    Permission is  hereby granted,  free of charge,  to any  person obtaining
diff --git a/contrib/expat/tests/structdata.c b/contrib/expat/tests/structdata.c
index e81b7b184601..d40e6c4b7e4b 100644
--- a/contrib/expat/tests/structdata.c
+++ b/contrib/expat/tests/structdata.c
@@ -6,8 +6,8 @@
                         \___/_/\_\ .__/ \__,_|\__|
                                  |_| XML parser
 
-   Copyright (c) 1997-2000 Thai Open Source Software Center Ltd
-   Copyright (c) 2000-2017 Expat development team
+   Copyright (c) 2017      Rhodri James <rhodri@wildebeest.org.uk>
+   Copyright (c) 2017-2021 Sebastian Pipping <sebastian@pipping.org>
    Licensed under the MIT license:
 
    Permission is  hereby granted,  free of charge,  to any  person obtaining
@@ -30,9 +30,7 @@
    USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
 
-#ifdef HAVE_EXPAT_CONFIG_H
-#  include "expat_config.h"
-#endif
+#include "expat_config.h"
 
 #include <assert.h>
 #include <stdlib.h>
diff --git a/contrib/expat/tests/structdata.h b/contrib/expat/tests/structdata.h
index 870ffaf2af05..09881b175f75 100644
--- a/contrib/expat/tests/structdata.h
+++ b/contrib/expat/tests/structdata.h
@@ -7,8 +7,7 @@
                         \___/_/\_\ .__/ \__,_|\__|
                                  |_| XML parser
 
-   Copyright (c) 1997-2000 Thai Open Source Software Center Ltd
-   Copyright (c) 2000-2017 Expat development team
+   Copyright (c) 2017 Rhodri James <rhodri@wildebeest.org.uk>
    Licensed under the MIT license:
 
    Permission is  hereby granted,  free of charge,  to any  person obtaining
diff --git a/contrib/expat/tests/udiffer.py b/contrib/expat/tests/udiffer.py
index 6fb91be7e3d0..2b58a4c34860 100755
--- a/contrib/expat/tests/udiffer.py
+++ b/contrib/expat/tests/udiffer.py
@@ -6,7 +6,8 @@
 #                      \___/_/\_\ .__/ \__,_|\__|
 #                               |_| XML parser
 #
-# Copyright (c) 2017 Expat development team
+# Copyright (c) 2017 Rhodri James <rhodri@wildebeest.org.uk>
+# Copyright (c) 2017 Sebastian Pipping <sebastian@pipping.org>
 # Licensed under the MIT license:
 #
 # Permission is  hereby granted,  free of charge,  to any  person obtaining
diff --git a/contrib/expat/tests/xmltest.sh b/contrib/expat/tests/xmltest.sh
index 9b5003511430..dc409d01e456 100755
--- a/contrib/expat/tests/xmltest.sh
+++ b/contrib/expat/tests/xmltest.sh
@@ -1,24 +1,55 @@
 #! /usr/bin/env bash
-
-#   EXPAT TEST SCRIPT FOR W3C XML TEST SUITE
-
+# EXPAT TEST SCRIPT FOR W3C XML TEST SUITE
+#
 # This script can be used to exercise Expat against the
 # w3c.org xml test suite, available from
 # http://www.w3.org/XML/Test/xmlts20020606.zip.
-
+#
 # To run this script, first set XMLWF below so that xmlwf can be
 # found, then set the output directory with OUTPUT.
-
+#
 # The script lists all test cases where Expat shows a discrepancy
 # from the expected result. Test cases where only the canonical
 # output differs are prefixed with "Output differs:", and a diff file
 # is generated in the appropriate subdirectory under $OUTPUT.
-
+#
 # If there are output files provided, the script will use
 # output from xmlwf and compare the desired output against it.
 # However, one has to take into account that the canonical output
 # produced by xmlwf conforms to an older definition of canonical XML
 # and does not generate notation declarations.
+#
+#                          __  __            _
+#                       ___\ \/ /_ __   __ _| |_
+#                      / _ \\  /| '_ \ / _` | __|
+#                     |  __//  \| |_) | (_| | |_
+#                      \___/_/\_\ .__/ \__,_|\__|
+#                               |_| XML parser
+#
+# Copyright (c) 2002-2004 Fred L. Drake, Jr. <fdrake@users.sourceforge.net>
+# Copyright (c) 2002      Karl Waclawek <karl@waclawek.net>
+# Copyright (c) 2008-2019 Sebastian Pipping <sebastian@pipping.org>
+# Copyright (c) 2017      Rhodri James <rhodri@wildebeest.org.uk>
+# Licensed under the MIT license:
+#
+# Permission is  hereby granted,  free of charge,  to any  person obtaining
+# a  copy  of  this  software   and  associated  documentation  files  (the
+# "Software"),  to  deal in  the  Software  without restriction,  including
+# without  limitation the  rights  to use,  copy,  modify, merge,  publish,
+# distribute, sublicense, and/or sell copies of the Software, and to permit
+# persons  to whom  the Software  is  furnished to  do so,  subject to  the
+# following conditions:
+#
+# The above copyright  notice and this permission notice  shall be included
+# in all copies or substantial portions of the Software.
+#
+# THE  SOFTWARE  IS  PROVIDED  "AS  IS",  WITHOUT  WARRANTY  OF  ANY  KIND,
+# EXPRESS  OR IMPLIED,  INCLUDING  BUT  NOT LIMITED  TO  THE WARRANTIES  OF
+# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+# NO EVENT SHALL THE AUTHORS OR  COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+# DAMAGES OR  OTHER LIABILITY, WHETHER  IN AN  ACTION OF CONTRACT,  TORT OR
+# OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+# USE OR OTHER DEALINGS IN THE SOFTWARE.
 
 shopt -s nullglob
 
diff --git a/contrib/expat/xmlwf/Makefile.am b/contrib/expat/xmlwf/Makefile.am
index 4b41c2cbdab8..c7eebd1eeec2 100644
--- a/contrib/expat/xmlwf/Makefile.am
+++ b/contrib/expat/xmlwf/Makefile.am
@@ -6,7 +6,7 @@
 #                      \___/_/\_\ .__/ \__,_|\__|
 #                               |_| XML parser
 #
-# Copyright (c) 2017 Expat development team
+# Copyright (c) 2017-2021 Sebastian Pipping <sebastian@pipping.org>
 # Licensed under the MIT license:
 #
 # Permission is  hereby granted,  free of charge,  to any  person obtaining
@@ -37,12 +37,13 @@ xmlwf_SOURCES = \
     codepage.c \
     @FILEMAP@.c
 
-xmlwf_CPPFLAGS = -I$(srcdir)/../lib
+xmlwf_CPPFLAGS = @AM_CPPFLAGS@ -I$(srcdir)/../lib
+xmlwf_LDFLAGS = @AM_LDFLAGS@ @LIBM@
 
 if MINGW
 if UNICODE
 xmlwf_CPPFLAGS += -mwindows
-xmlwf_LDFLAGS = -municode
+xmlwf_LDFLAGS += -municode
 endif
 endif
 
diff --git a/contrib/expat/xmlwf/Makefile.in b/contrib/expat/xmlwf/Makefile.in
index 368d3777431d..bcb36c2c2b9f 100644
--- a/contrib/expat/xmlwf/Makefile.in
+++ b/contrib/expat/xmlwf/Makefile.in
@@ -1,7 +1,7 @@
-# Makefile.in generated by automake 1.16.1 from Makefile.am.
+# Makefile.in generated by automake 1.16.5 from Makefile.am.
 # @configure_input@
 
-# Copyright (C) 1994-2018 Free Software Foundation, Inc.
+# Copyright (C) 1994-2021 Free Software Foundation, Inc.
 
 # This Makefile.in is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
@@ -22,7 +22,7 @@
 #                      \___/_/\_\ .__/ \__,_|\__|
 #                               |_| XML parser
 #
-# Copyright (c) 2017 Expat development team
+# Copyright (c) 2017-2021 Sebastian Pipping <sebastian@pipping.org>
 # Licensed under the MIT license:
 #
 # Permission is  hereby granted,  free of charge,  to any  person obtaining
@@ -120,6 +120,7 @@ build_triplet = @build@
 host_triplet = @host@
 bin_PROGRAMS = xmlwf$(EXEEXT)
 @MINGW_TRUE@@UNICODE_TRUE@am__append_1 = -mwindows
+@MINGW_TRUE@@UNICODE_TRUE@am__append_2 = -municode
 subdir = xmlwf
 ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
 am__aclocal_m4_deps = $(top_srcdir)/m4/libtool.m4 \
@@ -215,14 +216,16 @@ am__define_uniq_tagged_files = \
   unique=`for i in $$list; do \
     if test -f "$$i"; then echo $$i; else echo $(srcdir)/$$i; fi; \
   done | $(am__uniquify_input)`
-ETAGS = etags
-CTAGS = ctags
 am__DIST_COMMON = $(srcdir)/Makefile.in \
 	$(top_srcdir)/conftools/depcomp
 DISTFILES = $(DIST_COMMON) $(DIST_SOURCES) $(TEXINFOS) $(EXTRA_DIST)
 ACLOCAL = @ACLOCAL@
 AMTAR = @AMTAR@
+AM_CFLAGS = @AM_CFLAGS@
+AM_CPPFLAGS = @AM_CPPFLAGS@
+AM_CXXFLAGS = @AM_CXXFLAGS@
 AM_DEFAULT_VERBOSITY = @AM_DEFAULT_VERBOSITY@
+AM_LDFLAGS = @AM_LDFLAGS@
 AR = @AR@
 AS = @AS@
 AUTOCONF = @AUTOCONF@
@@ -232,8 +235,9 @@ AWK = @AWK@
 CC = @CC@
 CCDEPMODE = @CCDEPMODE@
 CFLAGS = @CFLAGS@
-CPP = @CPP@
 CPPFLAGS = @CPPFLAGS@
+CSCOPE = @CSCOPE@
+CTAGS = @CTAGS@
 CXX = @CXX@
 CXXCPP = @CXXCPP@
 CXXDEPMODE = @CXXDEPMODE@
@@ -249,7 +253,15 @@ ECHO_C = @ECHO_C@
 ECHO_N = @ECHO_N@
 ECHO_T = @ECHO_T@
 EGREP = @EGREP@
+ETAGS = @ETAGS@
 EXEEXT = @EXEEXT@
+EXPAT_ATTR_INFO = @EXPAT_ATTR_INFO@
+EXPAT_CHAR_TYPE = @EXPAT_CHAR_TYPE@
+EXPAT_CONTEXT_BYTES = @EXPAT_CONTEXT_BYTES@
+EXPAT_DTD = @EXPAT_DTD@
+EXPAT_LARGE_SIZE = @EXPAT_LARGE_SIZE@
+EXPAT_MIN_SIZE = @EXPAT_MIN_SIZE@
+EXPAT_NS = @EXPAT_NS@
 FGREP = @FGREP@
 FILEMAP = @FILEMAP@
 GREP = @GREP@
@@ -262,6 +274,8 @@ LD = @LD@
 LDFLAGS = @LDFLAGS@
 LIBAGE = @LIBAGE@
 LIBCURRENT = @LIBCURRENT@
+LIBDIR_BASENAME = @LIBDIR_BASENAME@
+LIBM = @LIBM@
 LIBOBJS = @LIBOBJS@
 LIBREVISION = @LIBREVISION@
 LIBS = @LIBS@
@@ -291,6 +305,9 @@ RANLIB = @RANLIB@
 SED = @SED@
 SET_MAKE = @SET_MAKE@
 SHELL = @SHELL@
+SO_MAJOR = @SO_MAJOR@
+SO_MINOR = @SO_MINOR@
+SO_PATCH = @SO_PATCH@
 STRIP = @STRIP@
 VERSION = @VERSION@
 abs_builddir = @abs_builddir@
@@ -301,6 +318,7 @@ ac_ct_AR = @ac_ct_AR@
 ac_ct_CC = @ac_ct_CC@
 ac_ct_CXX = @ac_ct_CXX@
 ac_ct_DUMPBIN = @ac_ct_DUMPBIN@
+ac_cv_sizeof_void_p = @ac_cv_sizeof_void_p@
 am__include = @am__include@
 am__leading_dot = @am__leading_dot@
 am__quote = @am__quote@
@@ -338,6 +356,7 @@ pdfdir = @pdfdir@
 prefix = @prefix@
 program_transform_name = @program_transform_name@
 psdir = @psdir@
+runstatedir = @runstatedir@
 sbindir = @sbindir@
 sharedstatedir = @sharedstatedir@
 srcdir = @srcdir@
@@ -353,8 +372,8 @@ xmlwf_SOURCES = \
     codepage.c \
     @FILEMAP@.c
 
-xmlwf_CPPFLAGS = -I$(srcdir)/../lib $(am__append_1)
-@MINGW_TRUE@@UNICODE_TRUE@xmlwf_LDFLAGS = -municode
+xmlwf_CPPFLAGS = @AM_CPPFLAGS@ -I$(srcdir)/../lib $(am__append_1)
+xmlwf_LDFLAGS = @AM_LDFLAGS@ @LIBM@ $(am__append_2)
 EXTRA_DIST = \
     codepage.h \
     ct.c \
@@ -605,7 +624,6 @@ cscopelist-am: $(am__tagged_files)
 
 distclean-tags:
 	-rm -f TAGS ID GTAGS GRTAGS GSYMS GPATH tags
-
 distdir: $(BUILT_SOURCES)
 	$(MAKE) $(AM_MAKEFLAGS) distdir-am
 
diff --git a/contrib/expat/xmlwf/codepage.c b/contrib/expat/xmlwf/codepage.c
index 1095adf63eb2..8e0b5d199cdd 100644
--- a/contrib/expat/xmlwf/codepage.c
+++ b/contrib/expat/xmlwf/codepage.c
@@ -7,7 +7,11 @@
                                  |_| XML parser
 
    Copyright (c) 1997-2000 Thai Open Source Software Center Ltd
-   Copyright (c) 2000-2017 Expat development team
+   Copyright (c) 2000      Clark Cooper <coopercc@users.sourceforge.net>
+   Copyright (c) 2002      Fred L. Drake, Jr. <fdrake@users.sourceforge.net>
+   Copyright (c) 2005-2006 Karl Waclawek <karl@waclawek.net>
+   Copyright (c) 2016-2019 Sebastian Pipping <sebastian@pipping.org>
+   Copyright (c) 2019      David Loffredo <loffredo@steptools.com>
    Licensed under the MIT license:
 
    Permission is  hereby granted,  free of charge,  to any  person obtaining
@@ -38,9 +42,11 @@
 #  define WIN32_LEAN_AND_MEAN 1
 
 #  include <windows.h>
+#endif /* defined(_WIN32) */
 
 int
 codepageMap(int cp, int *map) {
+#if defined(_WIN32)
   int i;
   CPINFO info;
   if (! GetCPInfo(cp, &info) || info.MaxCharSize > 2)
@@ -68,32 +74,25 @@ codepageMap(int cp, int *map) {
     }
   }
   return 1;
+#else
+  UNUSED_P(cp);
+  UNUSED_P(map);
+  return 0;
+#endif
 }
 
 int
 codepageConvert(int cp, const char *p) {
+#if defined(_WIN32)
   unsigned short c;
   if (MultiByteToWideChar(cp, MB_PRECOMPOSED | MB_ERR_INVALID_CHARS, p, 2, &c,
                           1)
       == 1)
     return c;
   return -1;
-}
-
-#else /* not _WIN32 */
-
-int
-codepageMap(int cp, int *map) {
-  UNUSED_P(cp);
-  UNUSED_P(map);
-  return 0;
-}
-
-int
-codepageConvert(int cp, const char *p) {
+#else
   UNUSED_P(cp);
   UNUSED_P(p);
   return -1;
+#endif
 }
-
-#endif /* not _WIN32 */
diff --git a/contrib/expat/xmlwf/codepage.h b/contrib/expat/xmlwf/codepage.h
index 1b75d58365f4..75ddbce4a456 100644
--- a/contrib/expat/xmlwf/codepage.h
+++ b/contrib/expat/xmlwf/codepage.h
@@ -7,7 +7,9 @@
                                  |_| XML parser
 
    Copyright (c) 1997-2000 Thai Open Source Software Center Ltd
-   Copyright (c) 2000-2017 Expat development team
+   Copyright (c) 2000      Clark Cooper <coopercc@users.sourceforge.net>
+   Copyright (c) 2002      Fred L. Drake, Jr. <fdrake@users.sourceforge.net>
+   Copyright (c) 2016-2017 Sebastian Pipping <sebastian@pipping.org>
    Licensed under the MIT license:
 
    Permission is  hereby granted,  free of charge,  to any  person obtaining
diff --git a/contrib/expat/xmlwf/ct.c b/contrib/expat/xmlwf/ct.c
index dcf92bab568b..d4c0e7a0a95d 100644
--- a/contrib/expat/xmlwf/ct.c
+++ b/contrib/expat/xmlwf/ct.c
@@ -7,7 +7,8 @@
                                  |_| XML parser
 
    Copyright (c) 1997-2000 Thai Open Source Software Center Ltd
-   Copyright (c) 2000-2017 Expat development team
+   Copyright (c) 2002      Fred L. Drake, Jr. <fdrake@users.sourceforge.net>
+   Copyright (c) 2016-2017 Sebastian Pipping <sebastian@pipping.org>
    Licensed under the MIT license:
 
    Permission is  hereby granted,  free of charge,  to any  person obtaining
diff --git a/contrib/expat/xmlwf/filemap.h b/contrib/expat/xmlwf/filemap.h
index ef66114422f3..5e0c70fa99b6 100644
--- a/contrib/expat/xmlwf/filemap.h
+++ b/contrib/expat/xmlwf/filemap.h
@@ -7,7 +7,9 @@
                                  |_| XML parser
 
    Copyright (c) 1997-2000 Thai Open Source Software Center Ltd
-   Copyright (c) 2000-2017 Expat development team
+   Copyright (c) 2000      Clark Cooper <coopercc@users.sourceforge.net>
+   Copyright (c) 2002      Fred L. Drake, Jr. <fdrake@users.sourceforge.net>
+   Copyright (c) 2016-2017 Sebastian Pipping <sebastian@pipping.org>
    Licensed under the MIT license:
 
    Permission is  hereby granted,  free of charge,  to any  person obtaining
diff --git a/contrib/expat/xmlwf/readfilemap.c b/contrib/expat/xmlwf/readfilemap.c
index d5b84f995ad4..59121f5b4dfe 100644
--- a/contrib/expat/xmlwf/readfilemap.c
+++ b/contrib/expat/xmlwf/readfilemap.c
@@ -7,7 +7,12 @@
                                  |_| XML parser
 
    Copyright (c) 1997-2000 Thai Open Source Software Center Ltd
-   Copyright (c) 2000-2017 Expat development team
+   Copyright (c) 2000      Clark Cooper <coopercc@users.sourceforge.net>
+   Copyright (c) 2001-2004 Fred L. Drake, Jr. <fdrake@users.sourceforge.net>
+   Copyright (c) 2002-2009 Karl Waclawek <karl@waclawek.net>
+   Copyright (c) 2016-2017 Sebastian Pipping <sebastian@pipping.org>
+   Copyright (c) 2017      Rhodri James <rhodri@wildebeest.org.uk>
+   Copyright (c) 2017      Franek Korta <fkorta@gmail.com>
    Licensed under the MIT license:
 
    Permission is  hereby granted,  free of charge,  to any  person obtaining
diff --git a/contrib/expat/xmlwf/unixfilemap.c b/contrib/expat/xmlwf/unixfilemap.c
index 0d0dc0424dc0..d0ce9cc60a8a 100644
--- a/contrib/expat/xmlwf/unixfilemap.c
+++ b/contrib/expat/xmlwf/unixfilemap.c
@@ -7,7 +7,11 @@
                                  |_| XML parser
 
    Copyright (c) 1997-2000 Thai Open Source Software Center Ltd
-   Copyright (c) 2000-2017 Expat development team
+   Copyright (c) 2000      Clark Cooper <coopercc@users.sourceforge.net>
+   Copyright (c) 2001-2002 Fred L. Drake, Jr. <fdrake@users.sourceforge.net>
+   Copyright (c) 2006      Karl Waclawek <karl@waclawek.net>
+   Copyright (c) 2016-2017 Sebastian Pipping <sebastian@pipping.org>
+   Copyright (c) 2017      Rhodri James <rhodri@wildebeest.org.uk>
    Licensed under the MIT license:
 
    Permission is  hereby granted,  free of charge,  to any  person obtaining
diff --git a/contrib/expat/xmlwf/win32filemap.c b/contrib/expat/xmlwf/win32filemap.c
index 0c9b7ecc5ffb..bde477772cb0 100644
--- a/contrib/expat/xmlwf/win32filemap.c
+++ b/contrib/expat/xmlwf/win32filemap.c
@@ -7,7 +7,9 @@
                                  |_| XML parser
 
    Copyright (c) 1997-2000 Thai Open Source Software Center Ltd
-   Copyright (c) 2000-2017 Expat development team
+   Copyright (c) 2000      Clark Cooper <coopercc@users.sourceforge.net>
+   Copyright (c) 2002      Fred L. Drake, Jr. <fdrake@users.sourceforge.net>
+   Copyright (c) 2016-2017 Sebastian Pipping <sebastian@pipping.org>
    Licensed under the MIT license:
 
    Permission is  hereby granted,  free of charge,  to any  person obtaining
diff --git a/contrib/expat/xmlwf/xmlfile.c b/contrib/expat/xmlwf/xmlfile.c
index 922e18b0b7e2..e3d6259a55fa 100644
--- a/contrib/expat/xmlwf/xmlfile.c
+++ b/contrib/expat/xmlwf/xmlfile.c
@@ -7,7 +7,14 @@
                                  |_| XML parser
 
    Copyright (c) 1997-2000 Thai Open Source Software Center Ltd
-   Copyright (c) 2000-2017 Expat development team
+   Copyright (c) 2000      Clark Cooper <coopercc@users.sourceforge.net>
+   Copyright (c) 2002-2003 Fred L. Drake, Jr. <fdrake@users.sourceforge.net>
+   Copyright (c) 2004-2006 Karl Waclawek <karl@waclawek.net>
+   Copyright (c) 2005-2007 Steven Solie <ssolie@users.sourceforge.net>
+   Copyright (c) 2016-2021 Sebastian Pipping <sebastian@pipping.org>
+   Copyright (c) 2017      Rhodri James <rhodri@wildebeest.org.uk>
+   Copyright (c) 2019      David Loffredo <loffredo@steptools.com>
+   Copyright (c) 2021      Dong-hee Na <donghee.na@python.org>
    Licensed under the MIT license:
 
    Permission is  hereby granted,  free of charge,  to any  person obtaining
@@ -30,6 +37,8 @@
    USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
 
+#include <expat_config.h>
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <stddef.h>
@@ -38,9 +47,7 @@
 
 #ifdef _WIN32
 #  include "winconfig.h"
-#elif defined(HAVE_EXPAT_CONFIG_H)
-#  include <expat_config.h>
-#endif /* ndef _WIN32 */
+#endif
 
 #include "expat.h"
 #include "internal.h" /* for UNUSED_P only */
@@ -176,7 +183,7 @@ externalEntityRefFilemap(XML_Parser parser, const XML_Char *context,
 
 static int
 processStream(const XML_Char *filename, XML_Parser parser) {
-  /* passing NULL for filename means read intput from stdin */
+  /* passing NULL for filename means read input from stdin */
   int fd = 0; /* 0 is the fileno for stdin */
 
   if (filename != NULL) {
diff --git a/contrib/expat/xmlwf/xmlfile.h b/contrib/expat/xmlwf/xmlfile.h
index 6e5d5b49eb78..d75dda222792 100644
--- a/contrib/expat/xmlwf/xmlfile.h
+++ b/contrib/expat/xmlwf/xmlfile.h
@@ -7,7 +7,10 @@
                                  |_| XML parser
 
    Copyright (c) 1997-2000 Thai Open Source Software Center Ltd
-   Copyright (c) 2000-2017 Expat development team
+   Copyright (c) 2000      Clark Cooper <coopercc@users.sourceforge.net>
+   Copyright (c) 2002      Fred L. Drake, Jr. <fdrake@users.sourceforge.net>
+   Copyright (c) 2005      Karl Waclawek <karl@waclawek.net>
+   Copyright (c) 2016-2019 Sebastian Pipping <sebastian@pipping.org>
    Licensed under the MIT license:
 
    Permission is  hereby granted,  free of charge,  to any  person obtaining
diff --git a/contrib/expat/xmlwf/xmlmime.c b/contrib/expat/xmlwf/xmlmime.c
index 39160d7198ce..883e293dac4f 100644
--- a/contrib/expat/xmlwf/xmlmime.c
+++ b/contrib/expat/xmlwf/xmlmime.c
@@ -7,7 +7,9 @@
                                  |_| XML parser
 
    Copyright (c) 1997-2000 Thai Open Source Software Center Ltd
-   Copyright (c) 2000-2017 Expat development team
+   Copyright (c) 2002      Fred L. Drake, Jr. <fdrake@users.sourceforge.net>
+   Copyright (c) 2016-2018 Sebastian Pipping <sebastian@pipping.org>
+   Copyright (c) 2018      Marco Maggi <marco.maggi-ipsu@poste.it>
    Licensed under the MIT license:
 
    Permission is  hereby granted,  free of charge,  to any  person obtaining
diff --git a/contrib/expat/xmlwf/xmlmime.h b/contrib/expat/xmlwf/xmlmime.h
index 0471286234a1..591a8847760c 100644
--- a/contrib/expat/xmlwf/xmlmime.h
+++ b/contrib/expat/xmlwf/xmlmime.h
@@ -7,7 +7,8 @@
                                  |_| XML parser
 
    Copyright (c) 1997-2000 Thai Open Source Software Center Ltd
-   Copyright (c) 2000-2017 Expat development team
+   Copyright (c) 2002      Fred L. Drake, Jr. <fdrake@users.sourceforge.net>
+   Copyright (c) 2016-2017 Sebastian Pipping <sebastian@pipping.org>
    Licensed under the MIT license:
 
    Permission is  hereby granted,  free of charge,  to any  person obtaining
diff --git a/contrib/expat/xmlwf/xmltchar.h b/contrib/expat/xmlwf/xmltchar.h
index d7e7b411b44b..30283d086dde 100644
--- a/contrib/expat/xmlwf/xmltchar.h
+++ b/contrib/expat/xmlwf/xmltchar.h
@@ -7,7 +7,8 @@
                                  |_| XML parser
 
    Copyright (c) 1997-2000 Thai Open Source Software Center Ltd
-   Copyright (c) 2000-2017 Expat development team
+   Copyright (c) 2016-2021 Sebastian Pipping <sebastian@pipping.org>
+   Copyright (c) 2017      Rhodri James <rhodri@wildebeest.org.uk>
    Licensed under the MIT license:
 
    Permission is  hereby granted,  free of charge,  to any  person obtaining
@@ -54,6 +55,8 @@
 #  define tmain wmain
 #  define tremove _wremove
 #  define tchar wchar_t
+#  define tcstof wcstof
+#  define tcstoull wcstoull
 #else /* not XML_UNICODE */
 #  define T(x) x
 #  define ftprintf fprintf
@@ -71,4 +74,6 @@
 #  define tmain main
 #  define tremove remove
 #  define tchar char
+#  define tcstof strtof
+#  define tcstoull strtoull
 #endif /* not XML_UNICODE */
diff --git a/contrib/expat/xmlwf/xmlurl.h b/contrib/expat/xmlwf/xmlurl.h
deleted file mode 100644
index f2cff093e2ea..000000000000
--- a/contrib/expat/xmlwf/xmlurl.h
+++ /dev/null
@@ -1,45 +0,0 @@
-/*
-                            __  __            _
-                         ___\ \/ /_ __   __ _| |_
-                        / _ \\  /| '_ \ / _` | __|
-                       |  __//  \| |_) | (_| | |_
-                        \___/_/\_\ .__/ \__,_|\__|
-                                 |_| XML parser
-
-   Copyright (c) 1997-2000 Thai Open Source Software Center Ltd
-   Copyright (c) 2000-2017 Expat development team
-   Licensed under the MIT license:
-
-   Permission is  hereby granted,  free of charge,  to any  person obtaining
-   a  copy  of  this  software   and  associated  documentation  files  (the
-   "Software"),  to  deal in  the  Software  without restriction,  including
-   without  limitation the  rights  to use,  copy,  modify, merge,  publish,
-   distribute, sublicense, and/or sell copies of the Software, and to permit
-   persons  to whom  the Software  is  furnished to  do so,  subject to  the
-   following conditions:
-
-   The above copyright  notice and this permission notice  shall be included
-   in all copies or substantial portions of the Software.
-
-   THE  SOFTWARE  IS  PROVIDED  "AS  IS",  WITHOUT  WARRANTY  OF  ANY  KIND,
-   EXPRESS  OR IMPLIED,  INCLUDING  BUT  NOT LIMITED  TO  THE WARRANTIES  OF
-   MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
-   NO EVENT SHALL THE AUTHORS OR  COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
-   DAMAGES OR  OTHER LIABILITY, WHETHER  IN AN  ACTION OF CONTRACT,  TORT OR
-   OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
-   USE OR OTHER DEALINGS IN THE SOFTWARE.
-*/
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-int XML_URLInit();
-void XML_URLUninit();
-int XML_ProcessURL(XML_Parser parser,
-                   const XML_Char *url,
-                   unsigned flags);
-
-#ifdef __cplusplus
-}
-#endif
diff --git a/contrib/expat/xmlwf/xmlwf.c b/contrib/expat/xmlwf/xmlwf.c
index 2d5a87e7d99d..29118bb64620 100644
--- a/contrib/expat/xmlwf/xmlwf.c
+++ b/contrib/expat/xmlwf/xmlwf.c
@@ -7,7 +7,16 @@
                                  |_| XML parser
 
    Copyright (c) 1997-2000 Thai Open Source Software Center Ltd
-   Copyright (c) 2000-2017 Expat development team
+   Copyright (c) 2000      Clark Cooper <coopercc@users.sourceforge.net>
+   Copyright (c) 2001-2003 Fred L. Drake, Jr. <fdrake@users.sourceforge.net>
+   Copyright (c) 2004-2009 Karl Waclawek <karl@waclawek.net>
+   Copyright (c) 2005-2007 Steven Solie <ssolie@users.sourceforge.net>
+   Copyright (c) 2016-2021 Sebastian Pipping <sebastian@pipping.org>
+   Copyright (c) 2017      Rhodri James <rhodri@wildebeest.org.uk>
+   Copyright (c) 2019      David Loffredo <loffredo@steptools.com>
+   Copyright (c) 2020      Joe Orton <jorton@redhat.com>
+   Copyright (c) 2020      Kleber Tarcísio <klebertarcisio@yahoo.com.br>
+   Copyright (c) 2021      Tim Bray <tbray@textuality.com>
    Licensed under the MIT license:
 
    Permission is  hereby granted,  free of charge,  to any  person obtaining
@@ -30,11 +39,15 @@
    USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
 
+#include <expat_config.h>
+
 #include <assert.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <stddef.h>
 #include <string.h>
+#include <math.h> /* for isnan */
+#include <errno.h>
 
 #include "expat.h"
 #include "codepage.h"
@@ -50,6 +63,14 @@
 #  include <wchar.h>
 #endif
 
+enum ExitCode {
+  XMLWF_EXIT_SUCCESS = 0,
+  XMLWF_EXIT_INTERNAL_ERROR = 1,
+  XMLWF_EXIT_NOT_WELLFORMED = 2,
+  XMLWF_EXIT_OUTPUT_ERROR = 3,
+  XMLWF_EXIT_USAGE_ERROR = 4,
+};
+
 /* Structures for handler user data */
 typedef struct NotationList {
   struct NotationList *next;
@@ -322,6 +343,13 @@ freeNotations(XmlwfUserData *data) {
   data->notationListHead = NULL;
 }
 
+static void
+cleanupUserData(XmlwfUserData *userData) {
+  free((void *)userData->currentDoctypeName);
+  userData->currentDoctypeName = NULL;
+  freeNotations(userData);
+}
+
 static int
 xcscmp(const XML_Char *xs, const XML_Char *xt) {
   while (*xs != 0 && *xt != 0) {
@@ -848,16 +876,19 @@ usage(const XML_Char *prog, int rc) {
       stderr,
       /* Generated with:
        * $ xmlwf/xmlwf_helpgen.sh
+       * To update, change xmlwf/xmlwf_helpgen.py, then paste the output of
+       * xmlwf/xmlwf_helpgen.sh in here.
        */
       /* clang-format off */
-      T("usage: %s [-s] [-n] [-p] [-x] [-e ENCODING] [-w] [-r] [-d DIRECTORY]\n")
-      T("             [-c | -m | -t] [-N]\n")
-      T("             [FILE [FILE ...]]\n")
+      T("usage:\n")
+      T("  %s [OPTIONS] [FILE ...]\n")
+      T("  %s -h\n")
+      T("  %s -v\n")
       T("\n")
       T("xmlwf - Determines if an XML document is well-formed\n")
       T("\n")
       T("positional arguments:\n")
-      T("  FILE          files to process (default: STDIN)\n")
+      T("  FILE          file to process (default: STDIN)\n")
       T("\n")
       T("input control arguments:\n")
       T("  -s            print an error if the document is not [s]tandalone\n")
@@ -867,6 +898,7 @@ usage(const XML_Char *prog, int rc) {
       T("  -e ENCODING   override any in-document [e]ncoding declaration\n")
       T("  -w            enable support for [W]indows code pages\n")
       T("  -r            disable memory-mapping and use normal file [r]ead IO calls instead\n")
+      T("  -k            when processing multiple files, [k]eep processing after first file with error\n")
       T("\n")
       T("output control arguments:\n")
       T("  -d DIRECTORY  output [d]estination directory\n")
@@ -875,14 +907,27 @@ usage(const XML_Char *prog, int rc) {
       T("  -t            write no XML output for [t]iming of plain parsing\n")
       T("  -N            enable adding doctype and [n]otation declarations\n")
       T("\n")
+      T("billion laughs attack protection:\n")
+      T("  NOTE: If you ever need to increase these values for non-attack payload, please file a bug report.\n")
+      T("\n")
+      T("  -a FACTOR     set maximum tolerated [a]mplification factor (default: 100.0)\n")
+      T("  -b BYTES      set number of output [b]ytes needed to activate (default: 8 MiB)\n")
+      T("\n")
       T("info arguments:\n")
       T("  -h            show this [h]elp message and exit\n")
       T("  -v            show program's [v]ersion number and exit\n")
       T("\n")
-      T("libexpat is software libre, licensed under the MIT license.\n")
+      T("exit status:\n")
+      T("  0             the input files are well-formed and the output (if requested) was written successfully\n")
+      T("  1             could not allocate data structures, signals a serious problem with execution environment\n")
+      T("  2             one or more input files were not well-formed\n")
+      T("  3             could not create an output file\n")
+      T("  4             command-line argument error\n")
+      T("\n")
+      T("xmlwf of libexpat is software libre, licensed under the MIT license.\n")
       T("Please report bugs at https://github.com/libexpat/libexpat/issues.  Thank you!\n")
       , /* clang-format on */
-      prog);
+      prog, prog, prog);
   exit(rc);
 }
 
@@ -891,6 +936,19 @@ usage(const XML_Char *prog, int rc) {
 int wmain(int argc, XML_Char **argv);
 #endif
 
+#define XMLWF_SHIFT_ARG_INTO(constCharStarTarget, argc, argv, i, j)            \
+  {                                                                            \
+    if (argv[i][j + 1] == T('\0')) {                                           \
+      if (++i == argc)                                                         \
+        usage(argv[0], XMLWF_EXIT_USAGE_ERROR);                                \
+      constCharStarTarget = argv[i];                                           \
+    } else {                                                                   \
+      constCharStarTarget = argv[i] + j + 1;                                   \
+    }                                                                          \
+    i++;                                                                       \
+    j = 0;                                                                     \
+  }
+
 int
 tmain(int argc, XML_Char **argv) {
   int i, j;
@@ -902,6 +960,13 @@ tmain(int argc, XML_Char **argv) {
   int useNamespaces = 0;
   int requireStandalone = 0;
   int requiresNotations = 0;
+  int continueOnError = 0;
+
+  float attackMaximumAmplification = -1.0f; /* signaling "not set" */
+  unsigned long long attackThresholdBytes;
+  XML_Bool attackThresholdGiven = XML_FALSE;
+
+  int exitCode = XMLWF_EXIT_SUCCESS;
   enum XML_ParamEntityParsing paramEntityParsing
       = XML_PARAM_ENTITY_PARSING_NEVER;
   int useStdin = 0;
@@ -965,31 +1030,64 @@ tmain(int argc, XML_Char **argv) {
       j++;
       break;
     case T('d'):
-      if (argv[i][j + 1] == T('\0')) {
-        if (++i == argc)
-          usage(argv[0], 2);
-        outputDir = argv[i];
-      } else
-        outputDir = argv[i] + j + 1;
-      i++;
-      j = 0;
+      XMLWF_SHIFT_ARG_INTO(outputDir, argc, argv, i, j);
       break;
     case T('e'):
-      if (argv[i][j + 1] == T('\0')) {
-        if (++i == argc)
-          usage(argv[0], 2);
-        encoding = argv[i];
-      } else
-        encoding = argv[i] + j + 1;
-      i++;
-      j = 0;
+      XMLWF_SHIFT_ARG_INTO(encoding, argc, argv, i, j);
       break;
     case T('h'):
-      usage(argv[0], 0);
+      usage(argv[0], XMLWF_EXIT_SUCCESS);
       return 0;
     case T('v'):
       showVersion(argv[0]);
       return 0;
+    case T('k'):
+      continueOnError = 1;
+      j++;
+      break;
+    case T('a'): {
+      const XML_Char *valueText = NULL;
+      XMLWF_SHIFT_ARG_INTO(valueText, argc, argv, i, j);
+
+      errno = 0;
+      XML_Char *afterValueText = (XML_Char *)valueText;
+      attackMaximumAmplification = tcstof(valueText, &afterValueText);
+      if ((errno != 0) || (afterValueText[0] != T('\0'))
+          || isnan(attackMaximumAmplification)
+          || (attackMaximumAmplification < 1.0f)) {
+        // This prevents tperror(..) from reporting misleading "[..]: Success"
+        errno = ERANGE;
+        tperror(T("invalid amplification limit") T(
+            " (needs a floating point number greater or equal than 1.0)"));
+        exit(XMLWF_EXIT_USAGE_ERROR);
+      }
+#ifndef XML_DTD
+      ftprintf(stderr, T("Warning: Given amplification limit ignored") T(
+                           ", xmlwf has been compiled without DTD support.\n"));
+#endif
+      break;
+    }
+    case T('b'): {
+      const XML_Char *valueText = NULL;
+      XMLWF_SHIFT_ARG_INTO(valueText, argc, argv, i, j);
+
+      errno = 0;
+      XML_Char *afterValueText = (XML_Char *)valueText;
+      attackThresholdBytes = tcstoull(valueText, &afterValueText, 10);
+      if ((errno != 0) || (afterValueText[0] != T('\0'))) {
+        // This prevents tperror(..) from reporting misleading "[..]: Success"
+        errno = ERANGE;
+        tperror(T("invalid ignore threshold")
+                    T(" (needs an integer from 0 to 2^64-1)"));
+        exit(XMLWF_EXIT_USAGE_ERROR);
+      }
+      attackThresholdGiven = XML_TRUE;
+#ifndef XML_DTD
+      ftprintf(stderr, T("Warning: Given attack threshold ignored") T(
+                           ", xmlwf has been compiled without DTD support.\n"));
+#endif
+      break;
+    }
     case T('\0'):
       if (j > 1) {
         i++;
@@ -998,7 +1096,7 @@ tmain(int argc, XML_Char **argv) {
       }
       /* fall through */
     default:
-      usage(argv[0], 2);
+      usage(argv[0], XMLWF_EXIT_USAGE_ERROR);
     }
   }
   if (i == argc) {
@@ -1017,7 +1115,22 @@ tmain(int argc, XML_Char **argv) {
 
     if (! parser) {
       tperror(T("Could not instantiate parser"));
-      exit(1);
+      exit(XMLWF_EXIT_INTERNAL_ERROR);
+    }
+
+    if (attackMaximumAmplification != -1.0f) {
+#ifdef XML_DTD
+      XML_SetBillionLaughsAttackProtectionMaximumAmplification(
+          parser, attackMaximumAmplification);
+#endif
+    }
+    if (attackThresholdGiven) {
+#ifdef XML_DTD
+      XML_SetBillionLaughsAttackProtectionActivationThreshold(
+          parser, attackThresholdBytes);
+#else
+      (void)attackThresholdBytes; // silence -Wunused-but-set-variable
+#endif
     }
 
     if (requireStandalone)
@@ -1051,13 +1164,24 @@ tmain(int argc, XML_Char **argv) {
       }
       outName = (XML_Char *)malloc((tcslen(outputDir) + tcslen(file) + 2)
                                    * sizeof(XML_Char));
+      if (! outName) {
+        tperror(T("Could not allocate memory"));
+        exit(XMLWF_EXIT_INTERNAL_ERROR);
+      }
       tcscpy(outName, outputDir);
       tcscat(outName, delim);
       tcscat(outName, file);
       userData.fp = tfopen(outName, T("wb"));
       if (! userData.fp) {
         tperror(outName);
-        exit(1);
+        exitCode = XMLWF_EXIT_OUTPUT_ERROR;
+        if (continueOnError) {
+          free(outName);
+          cleanupUserData(&userData);
+          continue;
+        } else {
+          break;
+        }
       }
       setvbuf(userData.fp, NULL, _IOFBF, 16384);
 #ifdef XML_UNICODE
@@ -1119,8 +1243,12 @@ tmain(int argc, XML_Char **argv) {
     }
     XML_ParserFree(parser);
     if (! result) {
-      exit(2);
+      exitCode = XMLWF_EXIT_NOT_WELLFORMED;
+      cleanupUserData(&userData);
+      if (! continueOnError) {
+        break;
+      }
     }
   }
-  return 0;
+  return exitCode;
 }
diff --git a/contrib/expat/xmlwf/xmlwf_helpgen.py b/contrib/expat/xmlwf/xmlwf_helpgen.py
index 0dcb6d34e37c..c2a527fde27d 100755
--- a/contrib/expat/xmlwf/xmlwf_helpgen.py
+++ b/contrib/expat/xmlwf/xmlwf_helpgen.py
@@ -6,7 +6,8 @@
 #                      \___/_/\_\ .__/ \__,_|\__|
 #                               |_| XML parser
 #
-# Copyright (c) 2019 Expat development team
+# Copyright (c) 2019-2021 Sebastian Pipping <sebastian@pipping.org>
+# Copyright (c) 2021      Tim Bray <tbray@textuality.com>
 # Licensed under the MIT license:
 #
 # Permission is  hereby granted,  free of charge,  to any  person obtaining
@@ -31,11 +32,25 @@
 import argparse
 
 epilog = """
-libexpat is software libre, licensed under the MIT license.
+exit status:
+  0             the input files are well-formed and the output (if requested) was written successfully
+  1             could not allocate data structures, signals a serious problem with execution environment
+  2             one or more input files were not well-formed
+  3             could not create an output file
+  4             command-line argument error
+
+xmlwf of libexpat is software libre, licensed under the MIT license.
 Please report bugs at https://github.com/libexpat/libexpat/issues.  Thank you!
 """
 
+usage = """
+  %(prog)s [OPTIONS] [FILE ...]
+  %(prog)s -h
+  %(prog)s -v
+"""
+
 parser = argparse.ArgumentParser(prog='xmlwf', add_help=False,
+                                 usage=usage,
                                  description='xmlwf - Determines if an XML document is well-formed',
                                  formatter_class=argparse.RawTextHelpFormatter,
                                  epilog=epilog)
@@ -48,6 +63,7 @@ input_related.add_argument('-x', action='store_true', help='enable processing of
 input_related.add_argument('-e', action='store', metavar='ENCODING', help='override any in-document [e]ncoding declaration')
 input_related.add_argument('-w', action='store_true', help='enable support for [W]indows code pages')
 input_related.add_argument('-r', action='store_true', help='disable memory-mapping and use normal file [r]ead IO calls instead')
+input_related.add_argument('-k', action='store_true', help='when processing multiple files, [k]eep processing after first file with error')
 
 output_related = parser.add_argument_group('output control arguments')
 output_related.add_argument('-d', action='store', metavar='DIRECTORY', help='output [d]estination directory')
@@ -57,7 +73,15 @@ output_mode.add_argument('-m', action='store_true', help='write [m]eta XML, not
 output_mode.add_argument('-t', action='store_true', help='write no XML output for [t]iming of plain parsing')
 output_related.add_argument('-N', action='store_true', help='enable adding doctype and [n]otation declarations')
 
-parser.add_argument('files', metavar='FILE', nargs='*', help='files to process (default: STDIN)')
+billion_laughs = parser.add_argument_group('billion laughs attack protection',
+                                           description='NOTE: '
+                                                       'If you ever need to increase these values '
+                                                       'for non-attack payload, please file a bug report.')
+billion_laughs.add_argument('-a', metavar='FACTOR',
+                            help='set maximum tolerated [a]mplification factor (default: 100.0)')
+billion_laughs.add_argument('-b', metavar='BYTES', help='set number of output [b]ytes needed to activate (default: 8 MiB)')
+
+parser.add_argument('files', metavar='FILE', nargs='*', help='file to process (default: STDIN)')
 
 info = parser.add_argument_group('info arguments')
 info = info.add_mutually_exclusive_group()
diff --git a/contrib/expat/xmlwf/xmlwf_helpgen.sh b/contrib/expat/xmlwf/xmlwf_helpgen.sh
index 6b0fbf929a09..864e47086d15 100755
--- a/contrib/expat/xmlwf/xmlwf_helpgen.sh
+++ b/contrib/expat/xmlwf/xmlwf_helpgen.sh
@@ -6,7 +6,7 @@
 #                      \___/_/\_\ .__/ \__,_|\__|
 #                               |_| XML parser
 #
-# Copyright (c) 2019 Expat development team
+# Copyright (c) 2019-2021 Sebastian Pipping <sebastian@pipping.org>
 # Licensed under the MIT license:
 #
 # Permission is  hereby granted,  free of charge,  to any  person obtaining
@@ -29,7 +29,8 @@
 # USE OR OTHER DEALINGS IN THE SOFTWARE.
 
 ./xmlwf/xmlwf_helpgen.py | sed \
-        -e 's,usage: xmlwf,usage: %s,' \
+        -e 's,usage: ,usage:,' \
+        -e 's,  xmlwf,  %s,' \
         -e 's, \[-h | -v\],,' \
         -e 's,^,      T(",' \
         -e 's,$,\\n"),'
diff --git a/contrib/expat/xmlwf/xmlwin32url.cxx b/contrib/expat/xmlwf/xmlwin32url.cxx
deleted file mode 100644
index ef2a137452e7..000000000000
--- a/contrib/expat/xmlwf/xmlwin32url.cxx
+++ /dev/null
@@ -1,427 +0,0 @@
-/*
-                            __  __            _
-                         ___\ \/ /_ __   __ _| |_
-                        / _ \\  /| '_ \ / _` | __|
-                       |  __//  \| |_) | (_| | |_
-                        \___/_/\_\ .__/ \__,_|\__|
-                                 |_| XML parser
-
-   Copyright (c) 1997-2000 Thai Open Source Software Center Ltd
-   Copyright (c) 2000-2017 Expat development team
-   Licensed under the MIT license:
-
-   Permission is  hereby granted,  free of charge,  to any  person obtaining
-   a  copy  of  this  software   and  associated  documentation  files  (the
-   "Software"),  to  deal in  the  Software  without restriction,  including
-   without  limitation the  rights  to use,  copy,  modify, merge,  publish,
-   distribute, sublicense, and/or sell copies of the Software, and to permit
-   persons  to whom  the Software  is  furnished to  do so,  subject to  the
-   following conditions:
-
-   The above copyright  notice and this permission notice  shall be included
-   in all copies or substantial portions of the Software.
-
-   THE  SOFTWARE  IS  PROVIDED  "AS  IS",  WITHOUT  WARRANTY  OF  ANY  KIND,
-   EXPRESS  OR IMPLIED,  INCLUDING  BUT  NOT LIMITED  TO  THE WARRANTIES  OF
-   MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
-   NO EVENT SHALL THE AUTHORS OR  COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
-   DAMAGES OR  OTHER LIABILITY, WHETHER  IN AN  ACTION OF CONTRACT,  TORT OR
-   OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
-   USE OR OTHER DEALINGS IN THE SOFTWARE.
-*/
-
-#include "expat.h"
-#ifdef XML_UNICODE
-#define UNICODE
-#endif
-#include <windows.h>
-#include <urlmon.h>
-#include <wininet.h>
-#include <stdio.h>
-#include <tchar.h>
-#include "xmlurl.h"
-#include "xmlmime.h"
-
-static int
-processURL(XML_Parser parser, IMoniker *baseMoniker, const XML_Char *url);
-
-typedef void (*StopHandler)(void *, HRESULT);
-
-class Callback : public IBindStatusCallback {
-public:
-  // IUnknown methods
-  STDMETHODIMP QueryInterface(REFIID,void **);
-  STDMETHODIMP_(ULONG) AddRef();
-  STDMETHODIMP_(ULONG) Release();
-  // IBindStatusCallback methods
-  STDMETHODIMP OnStartBinding(DWORD, IBinding *);
-  STDMETHODIMP GetPriority(LONG *);
-  STDMETHODIMP OnLowResource(DWORD);
-  STDMETHODIMP OnProgress(ULONG, ULONG, ULONG, LPCWSTR);
-  STDMETHODIMP OnStopBinding(HRESULT, LPCWSTR);
-  STDMETHODIMP GetBindInfo(DWORD *, BINDINFO *);
-  STDMETHODIMP OnDataAvailable(DWORD, DWORD, FORMATETC *, STGMEDIUM *);
-  STDMETHODIMP OnObjectAvailable(REFIID, IUnknown *);
-  Callback(XML_Parser, IMoniker *, StopHandler, void *);
-  ~Callback();
-  int externalEntityRef(const XML_Char *context,
-                        const XML_Char *systemId, const XML_Char *publicId);
-private:
-  XML_Parser parser_;
-  IMoniker *baseMoniker_;
-  DWORD totalRead_;
-  ULONG ref_;
-  IBinding *pBinding_;
-  StopHandler stopHandler_;
-  void *stopArg_;
-};
-
-STDMETHODIMP_(ULONG)
-Callback::AddRef()
-{ 
-  return ref_++;
-}
-
-STDMETHODIMP_(ULONG)
-Callback::Release()
-{ 
-  if (--ref_ == 0) {
-    delete this;
-    return 0;
-  }
-  return ref_;
-}
-
-STDMETHODIMP
-Callback::QueryInterface(REFIID riid, void** ppv)
-{ 
-  if (IsEqualGUID(riid, IID_IUnknown))
-    *ppv = (IUnknown *)this;
-  else if (IsEqualGUID(riid, IID_IBindStatusCallback))
-    *ppv = (IBindStatusCallback *)this;
-  else
-    return E_NOINTERFACE;
-  ((LPUNKNOWN)*ppv)->AddRef();
-  return S_OK;
-}
-
-STDMETHODIMP
-Callback::OnStartBinding(DWORD, IBinding* pBinding)
-{
-  pBinding_ = pBinding;
-  pBinding->AddRef();
-  return S_OK;
-}
-
-STDMETHODIMP
-Callback::GetPriority(LONG *)
-{
-  return E_NOTIMPL;
-}
-
-STDMETHODIMP
-Callback::OnLowResource(DWORD)
-{
-  return E_NOTIMPL;
-}
-
-STDMETHODIMP
-Callback::OnProgress(ULONG, ULONG, ULONG, LPCWSTR)
-{
-  return S_OK;
-}
-
-STDMETHODIMP
-Callback::OnStopBinding(HRESULT hr, LPCWSTR szError)
-{
-  if (pBinding_) {
-    pBinding_->Release();
-    pBinding_ = 0;
-  }
-  if (baseMoniker_) {
-    baseMoniker_->Release();
-    baseMoniker_ = 0;
-  }
-  stopHandler_(stopArg_, hr);
-  return S_OK;
-}
-
-STDMETHODIMP
-Callback::GetBindInfo(DWORD* pgrfBINDF, BINDINFO* pbindinfo)
-{
-  *pgrfBINDF = BINDF_ASYNCHRONOUS;
-  return S_OK;
-}
-
-static void
-reportError(XML_Parser parser)
-{
-  int code = XML_GetErrorCode(parser);
-  const XML_Char *message = XML_ErrorString(code);
-  if (message)
-    _ftprintf(stderr, _T("%s:%d:%ld: %s\n"),
-	     XML_GetBase(parser),
-	     XML_GetErrorLineNumber(parser),
-	     XML_GetErrorColumnNumber(parser),
-	     message);
-  else
-    _ftprintf(stderr, _T("%s: (unknown message %d)\n"),
-              XML_GetBase(parser), code);
-}
-
-STDMETHODIMP
-Callback::OnDataAvailable(DWORD grfBSCF,
-                          DWORD dwSize,
-                          FORMATETC *pfmtetc,
-                          STGMEDIUM* pstgmed)
-{
-  if (grfBSCF & BSCF_FIRSTDATANOTIFICATION) {
-    IWinInetHttpInfo *hp;
-    HRESULT hr = pBinding_->QueryInterface(IID_IWinInetHttpInfo,
-                                           (void **)&hp);
-    if (SUCCEEDED(hr)) {
-      char contentType[1024];
-      DWORD bufSize = sizeof(contentType);
-      DWORD flags = 0;
-      contentType[0] = 0;
-      hr = hp->QueryInfo(HTTP_QUERY_CONTENT_TYPE, contentType,
-                         &bufSize, 0, NULL);
-      if (SUCCEEDED(hr)) {
-	char charset[CHARSET_MAX];
-	getXMLCharset(contentType, charset);
-	if (charset[0]) {
-#ifdef XML_UNICODE
-	  XML_Char wcharset[CHARSET_MAX];
-	  XML_Char *p1 = wcharset;
-	  const char *p2 = charset;
-	  while ((*p1++ = (unsigned char)*p2++) != 0)
-	    ;
-	  XML_SetEncoding(parser_, wcharset);
-#else
-	  XML_SetEncoding(parser_, charset);
-#endif
-	}
-      }
-      hp->Release();
-    }
-  }
-  if (!parser_)
-    return E_ABORT;
-  if (pstgmed->tymed == TYMED_ISTREAM) {
-    while (totalRead_ < dwSize) {
-#define READ_MAX (64*1024)
-      DWORD nToRead = dwSize - totalRead_;
-      if (nToRead > READ_MAX)
-	nToRead = READ_MAX;
-      void *buf = XML_GetBuffer(parser_, nToRead);
-      if (!buf) {
-	_ftprintf(stderr, _T("out of memory\n"));
-	return E_ABORT;
-      }
-      DWORD nRead;
-      HRESULT hr = pstgmed->pstm->Read(buf, nToRead, &nRead);
-      if (SUCCEEDED(hr)) {
-	totalRead_ += nRead;
-	if (!XML_ParseBuffer(parser_,
-			     nRead,
-			     (grfBSCF & BSCF_LASTDATANOTIFICATION) != 0
-			     && totalRead_ == dwSize)) {
-	  reportError(parser_);
-	  return E_ABORT;
-	}
-      }
-    }
-  }
-  return S_OK;
-}
-
-STDMETHODIMP
-Callback::OnObjectAvailable(REFIID, IUnknown *)
-{
-  return S_OK;
-}
-
-int
-Callback::externalEntityRef(const XML_Char *context,
-                            const XML_Char *systemId,
-                            const XML_Char *publicId)
-{
-  XML_Parser entParser = XML_ExternalEntityParserCreate(parser_, context, 0);
-  XML_SetBase(entParser, systemId);
-  int ret = processURL(entParser, baseMoniker_, systemId);
-  XML_ParserFree(entParser);
-  return ret;
-}
-
-Callback::Callback(XML_Parser parser, IMoniker *baseMoniker,
-                   StopHandler stopHandler, void *stopArg)
-: parser_(parser),
-  baseMoniker_(baseMoniker),
-  ref_(0),
-  pBinding_(0),
-  totalRead_(0),
-  stopHandler_(stopHandler),
-  stopArg_(stopArg)
-{
-  if (baseMoniker_)
-    baseMoniker_->AddRef();
-}
-
-Callback::~Callback()
-{
-  if (pBinding_)
-    pBinding_->Release();
-  if (baseMoniker_)
-    baseMoniker_->Release();
-}
-
-static int
-externalEntityRef(void *arg,
-                  const XML_Char *context,
-                  const XML_Char *base,
-                  const XML_Char *systemId,
-                  const XML_Char *publicId)
-{
-  return ((Callback *)arg)->externalEntityRef(context, systemId, publicId);
-}
-
-
-static HRESULT
-openStream(XML_Parser parser,
-           IMoniker *baseMoniker,
-           const XML_Char *uri,
-           StopHandler stopHandler, void *stopArg)
-{
-  if (!XML_SetBase(parser, uri))
-    return E_OUTOFMEMORY;
-  HRESULT hr;
-  IMoniker *m;
-#ifdef XML_UNICODE
-  hr = CreateURLMoniker(0, uri, &m);
-#else
-  LPWSTR uriw = new wchar_t[strlen(uri) + 1];
-  for (int i = 0;; i++) {
-    uriw[i] = uri[i];
-    if (uriw[i] == 0)
-      break;
-  }
-  hr = CreateURLMoniker(baseMoniker, uriw, &m);
-  delete [] uriw;
-#endif
-  if (FAILED(hr))
-    return hr;
-  IBindStatusCallback *cb = new Callback(parser, m, stopHandler, stopArg);
-  XML_SetExternalEntityRefHandler(parser, externalEntityRef);
-  XML_SetExternalEntityRefHandlerArg(parser, cb);
-  cb->AddRef();
-  IBindCtx *b;
-  if (FAILED(hr = CreateAsyncBindCtx(0, cb, 0, &b))) {
-    cb->Release();
-    m->Release();
-    return hr;
-  }
-  cb->Release();
-  IStream *pStream;
-  hr = m->BindToStorage(b, 0, IID_IStream, (void **)&pStream);
-  if (SUCCEEDED(hr)) {
-    if (pStream)
-      pStream->Release();
-  }
-  if (hr == MK_S_ASYNCHRONOUS)
-    hr = S_OK;
-  m->Release();
-  b->Release();
-  return hr;
-}
-
-struct QuitInfo {
-  const XML_Char *url;
-  HRESULT hr;
-  int stop;
-};
-
-static void
-winPerror(const XML_Char *url, HRESULT hr)
-{
-  LPVOID buf;
-  if (FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER
-		    | FORMAT_MESSAGE_FROM_HMODULE,
-		    GetModuleHandleA("urlmon.dll"),
-		    hr,
-		    MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
-		    (LPTSTR) &buf,
-		    0,
-		    NULL)
-      || FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER
-		      | FORMAT_MESSAGE_FROM_SYSTEM,
-		      0,
-		      hr,
-		      MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
-		      (LPTSTR) &buf,
-		      0,
-		      NULL)) {
-    /* The system error messages seem to end with a newline. */
-    _ftprintf(stderr, _T("%s: %s"), url, buf);
-    fflush(stderr);
-    LocalFree(buf);
-  }
-  else
-    _ftprintf(stderr, _T("%s: error %x\n"), url, hr);
-}
-
-static void
-threadQuit(void *p, HRESULT hr)
-{
-  QuitInfo *qi = (QuitInfo *)p;
-  qi->hr = hr;
-  qi->stop = 1;
-}
-
-extern "C"
-int
-XML_URLInit(void)
-{
-  return SUCCEEDED(CoInitialize(0));
-}
-
-extern "C"
-void
-XML_URLUninit(void)
-{
-  CoUninitialize();
-}
-
-static int
-processURL(XML_Parser parser, IMoniker *baseMoniker,
-           const XML_Char *url)
-{
-  QuitInfo qi;
-  qi.stop = 0;
-  qi.url = url;
-
-  XML_SetBase(parser, url);
-  HRESULT hr = openStream(parser, baseMoniker, url, threadQuit, &qi);
-  if (FAILED(hr)) {
-    winPerror(url, hr);
-    return 0;
-  }
-  else if (FAILED(qi.hr)) {
-    winPerror(url, qi.hr);
-    return 0;
-  }
-  MSG msg;
-  while (!qi.stop && GetMessage (&msg, NULL, 0, 0)) {
-    TranslateMessage (&msg);
-    DispatchMessage (&msg);
-  }
-  return 1;
-}
-
-extern "C"
-int
-XML_ProcessURL(XML_Parser parser,
-               const XML_Char *url,
-               unsigned flags)
-{
-  return processURL(parser, 0, url);
-}
diff --git a/lib/libexpat/expat_config.h b/lib/libexpat/expat_config.h
index d4cb92cafdb5..e2ffcb15c7ef 100644
--- a/lib/libexpat/expat_config.h
+++ b/lib/libexpat/expat_config.h
@@ -1,5 +1,3 @@
-/* $FreeBSD$ */
-
 /* expat_config.h.  Generated from expat_config.h.in by configure.  */
 /* expat_config.h.in.  Generated from configure.ac by autoheader.  */
 
@@ -39,15 +37,15 @@
 /* Define to 1 if you have the `bsd' library (-lbsd). */
 /* #undef HAVE_LIBBSD */
 
-/* Define to 1 if you have the <memory.h> header file. */
-#define HAVE_MEMORY_H 1
-
 /* Define to 1 if you have a working `mmap' system call. */
 #define HAVE_MMAP 1
 
 /* Define to 1 if you have the <stdint.h> header file. */
 #define HAVE_STDINT_H 1
 
+/* Define to 1 if you have the <stdio.h> header file. */
+#define HAVE_STDIO_H 1
+
 /* Define to 1 if you have the <stdlib.h> header file. */
 #define HAVE_STDLIB_H 1
 
@@ -85,7 +83,7 @@
 #define PACKAGE_NAME "expat"
 
 /* Define to the full name and version of this package. */
-#define PACKAGE_STRING "expat 2.2.9"
+#define PACKAGE_STRING "expat 2.4.3"
 
 /* Define to the one symbol short name of this package. */
 #define PACKAGE_TARNAME "expat"
@@ -94,13 +92,15 @@
 #define PACKAGE_URL ""
 
 /* Define to the version of this package. */
-#define PACKAGE_VERSION "2.2.9"
+#define PACKAGE_VERSION "2.4.3"
 
-/* Define to 1 if you have the ANSI C header files. */
+/* Define to 1 if all of the C90 standard headers exist (not just the ones
+   required in a freestanding environment). This macro is provided for
+   backward compatibility; new code need not use it. */
 #define STDC_HEADERS 1
 
 /* Version number of package */
-#define VERSION "2.2.9"
+#define VERSION "2.4.3"
 
 /* Define WORDS_BIGENDIAN to 1 if your processor stores words with the most
    significant byte first (like Motorola and SPARC, unlike Intel). */