loader: add support for gzip compression

As we do have zlib code in loader, we should also support gzip
compression in zfs.

PR:		153173
Submitted by:	Mikhail Zakharov <zmey20000@yahoo.com>
Reviewed by:	imp, markj, delphij
Differential Revision: https://reviews.freebsd.org/D35320
MFC after:	1 month

3 files changed, 107 insertions, 9 deletions

diff --git a/sys/cddl/boot/zfs/README b/sys/cddl/boot/zfs/README
index 5f16d5cddf26..0c2006096c99 100644
--- a/sys/cddl/boot/zfs/README
+++ b/sys/cddl/boot/zfs/README
@@ -5,6 +5,7 @@ are used by the ZFS bootstrap:
 
     fletcher.c			checksum support
     sha256.c			checksum support
+    gzip.c			compression support
     lz4.c			compression support
     lzjb.c			compression support
     blkptr.c			ZFS embedded-data block pointers support
diff --git a/sys/cddl/boot/zfs/gzip.c b/sys/cddl/boot/zfs/gzip.c
new file mode 100644
index 000000000000..35b5a3241dc0
--- /dev/null
+++ b/sys/cddl/boot/zfs/gzip.c
@@ -0,0 +1,96 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+
+/*
+ * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
+ * Use is subject to license terms.
+ */
+
+/*
+ * Portions Copyright 2022 Mikhail Zakharov <zmey20000@yahoo.com>
+ */
+
+#include <contrib/zlib/zlib.h>
+#include <contrib/zlib/zutil.h>
+
+static void *
+zfs_zcalloc(void *opaque __unused, uint_t items, uint_t size)
+{
+
+	return (calloc(items, size));
+}
+
+static void
+zfs_zcfree(void *opaque __unused, void *ptr)
+{
+	free(ptr);
+}
+
+/*
+ * Uncompress the buffer 'src' into the buffer 'dst'.  The caller must store
+ * the expected decompressed data size externally so it can be passed in.
+ * The resulting decompressed size is then returned through dstlen.  This
+ * function return Z_OK on success, or another error code on failure.
+ */
+static inline int
+z_uncompress(void *dst, size_t *dstlen, const void *src, size_t srclen)
+{
+	z_stream zs;
+	int err;
+
+	bzero(&zs, sizeof (zs));
+	zs.next_in = (unsigned char *)src;
+	zs.avail_in = srclen;
+	zs.next_out = dst;
+	zs.avail_out = *dstlen;
+	zs.zalloc = zfs_zcalloc;
+	zs.zfree = zfs_zcfree;
+
+	/*
+	 * Call inflateInit2() specifying a window size of DEF_WBITS
+	 * with the 6th bit set to indicate that the compression format
+	 * type (zlib or gzip) should be automatically detected.
+	 */
+	if ((err = inflateInit2(&zs, DEF_WBITS | 0x20)) != Z_OK)
+		return (err);
+
+	if ((err = inflate(&zs, Z_FINISH)) != Z_STREAM_END) {
+		(void) inflateEnd(&zs);
+		return (err == Z_OK ? Z_BUF_ERROR : err);
+	}
+
+	*dstlen = zs.total_out;
+	return (inflateEnd(&zs));
+}
+
+static int
+gzip_decompress(void *s_start, void *d_start, size_t s_len, size_t d_len,
+    int n __unused)
+{
+	size_t dstlen = d_len;
+
+	ASSERT(d_len >= s_len);
+
+	if (z_uncompress(d_start, &dstlen, s_start, s_len) != Z_OK)
+		return (-1);
+
+	return (0);
+}
diff --git a/sys/cddl/boot/zfs/zfssubr.c b/sys/cddl/boot/zfs/zfssubr.c
index 2603a69d6f9f..2e309fc10be4 100644
--- a/sys/cddl/boot/zfs/zfssubr.c
+++ b/sys/cddl/boot/zfs/zfssubr.c
@@ -163,6 +163,7 @@ typedef struct zio_compress_info {
 
 #include "lzjb.c"
 #include "zle.c"
+#include "gzip.c"
 
 /*
  * Compression vectors.
@@ -173,15 +174,15 @@ static zio_compress_info_t zio_compress_table[ZIO_COMPRESS_FUNCTIONS] = {
 	{NULL,			NULL,			0,	"uncompressed"},
 	{NULL,			lzjb_decompress,	0,	"lzjb"},
 	{NULL,			NULL,			0,	"empty"},
-	{NULL,			NULL,			1,	"gzip-1"},
-	{NULL,			NULL,			2,	"gzip-2"},
-	{NULL,			NULL,			3,	"gzip-3"},
-	{NULL,			NULL,			4,	"gzip-4"},
-	{NULL,			NULL,			5,	"gzip-5"},
-	{NULL,			NULL,			6,	"gzip-6"},
-	{NULL,			NULL,			7,	"gzip-7"},
-	{NULL,			NULL,			8,	"gzip-8"},
-	{NULL,			NULL,			9,	"gzip-9"},
+	{NULL,			gzip_decompress,	1,	"gzip-1"},
+	{NULL,			gzip_decompress,	2,	"gzip-2"},
+	{NULL,			gzip_decompress,	3,	"gzip-3"},
+	{NULL,			gzip_decompress,	4,	"gzip-4"},
+	{NULL,			gzip_decompress,	5,	"gzip-5"},
+	{NULL,			gzip_decompress,	6,	"gzip-6"},
+	{NULL,			gzip_decompress,	7,	"gzip-7"},
+	{NULL,			gzip_decompress,	8,	"gzip-8"},
+	{NULL,			gzip_decompress,	9,	"gzip-9"},
 	{NULL,			zle_decompress,		64,	"zle"},
 	{NULL,			lz4_decompress,		0,	"lz4"},
 #ifdef HAS_ZSTD_ZFS