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author | Ka Ho Ng <khng@FreeBSD.org> | 2024-10-08 04:24:07 +0000 |
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committer | Ka Ho Ng <khng@FreeBSD.org> | 2024-10-08 04:24:07 +0000 |
commit | 0a2cfd653e86ac41c4e6e32a449d133c0ee6d677 (patch) | |
tree | 500d6a02aeb037c735bfe39fecb5cac9763d012b /lib/libkldelf/ef_i386.c | |
parent | 6c711019f289320f38eda47dcb55b188342a4476 (diff) | |
download | src-0a2cfd653e86ac41c4e6e32a449d133c0ee6d677.tar.gz src-0a2cfd653e86ac41c4e6e32a449d133c0ee6d677.zip |
libkldelf: add a private library for kernel/kld-related ELF parsing
The libkldelf library was originally a part of kldxref(8). It exposed
ELF parsing helpers specialized in parsing KLDs and the kernel
executable. The library can be used to read metadata such as linker_set,
mod_depend, mod_version and PNP match info, and raw data from the ELF.
To promote the reuse of the facilities the ELF parsing code is separated
from kldxref(8) into a new private library.
kldxref(8) is modified to link against the libkldelf library.
Sponsored by: Juniper Networks, Inc.
Reviewed by: markj
Differential Revision: https://reviews.freebsd.org/D46719
Diffstat (limited to 'lib/libkldelf/ef_i386.c')
-rw-r--r-- | lib/libkldelf/ef_i386.c | 97 |
1 files changed, 97 insertions, 0 deletions
diff --git a/lib/libkldelf/ef_i386.c b/lib/libkldelf/ef_i386.c new file mode 100644 index 000000000000..ae571e2d50f2 --- /dev/null +++ b/lib/libkldelf/ef_i386.c @@ -0,0 +1,97 @@ +/*- + * SPDX-License-Identifier: BSD-2-Clause + * + * Copyright (c) 2003 Jake Burkholder. + * Copyright 1996-1998 John D. Polstra. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#include <sys/endian.h> + +#include <err.h> +#include <errno.h> +#include <gelf.h> + +#include "kldelf.h" + +/* + * Apply relocations to the values obtained from the file. `relbase' is the + * target relocation address of the section, and `dataoff/len' is the region + * that is to be relocated, and has been copied to *dest + */ +static int +ef_i386_reloc(struct elf_file *ef, const void *reldata, Elf_Type reltype, + GElf_Addr relbase, GElf_Addr dataoff, size_t len, void *dest) +{ + char *where; + GElf_Addr addr, addend; + GElf_Size rtype, symidx; + const GElf_Rel *rel; + const GElf_Rela *rela; + + switch (reltype) { + case ELF_T_REL: + rel = (const GElf_Rel *)reldata; + where = (char *)dest + (relbase + rel->r_offset - dataoff); + addend = 0; + rtype = GELF_R_TYPE(rel->r_info); + symidx = GELF_R_SYM(rel->r_info); + break; + case ELF_T_RELA: + rela = (const GElf_Rela *)reldata; + where = (char *)dest + (relbase + rela->r_offset - dataoff); + addend = rela->r_addend; + rtype = GELF_R_TYPE(rela->r_info); + symidx = GELF_R_SYM(rela->r_info); + break; + default: + return (EINVAL); + } + + if (where < (char *)dest || where >= (char *)dest + len) + return (0); + + if (reltype == ELF_T_REL) + addend = le32dec(where); + + switch (rtype) { + case R_386_RELATIVE: /* B + A */ + addr = relbase + addend; + le32enc(where, addr); + break; + case R_386_32: /* S + A - P */ + addr = EF_SYMADDR(ef, symidx) + addend; + le32enc(where, addr); + break; + case R_386_GLOB_DAT: /* S */ + addr = EF_SYMADDR(ef, symidx); + le32enc(where, addr); + break; + default: + warnx("unhandled relocation type %d", (int)rtype); + } + return (0); +} + +ELF_RELOC(ELFCLASS32, ELFDATA2LSB, EM_386, ef_i386_reloc); |