xref: /freebsd/sys/cddl/boot/zfs/gzip.c (revision 2e3f49888ec8851bafb22011533217487764fdb0)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 /*
28  * Portions Copyright 2022 Mikhail Zakharov <zmey20000@yahoo.com>
29  */
30 
31 #include <contrib/zlib/zlib.h>
32 #include <contrib/zlib/zutil.h>
33 
34 static void *
35 zfs_zcalloc(void *opaque __unused, uint_t items, uint_t size)
36 {
37 
38 	return (calloc(items, size));
39 }
40 
41 static void
42 zfs_zcfree(void *opaque __unused, void *ptr)
43 {
44 	free(ptr);
45 }
46 
47 /*
48  * Uncompress the buffer 'src' into the buffer 'dst'.  The caller must store
49  * the expected decompressed data size externally so it can be passed in.
50  * The resulting decompressed size is then returned through dstlen.  This
51  * function return Z_OK on success, or another error code on failure.
52  */
53 static inline int
54 z_uncompress(void *dst, size_t *dstlen, const void *src, size_t srclen)
55 {
56 	z_stream zs;
57 	int err;
58 
59 	bzero(&zs, sizeof (zs));
60 	zs.next_in = (unsigned char *)src;
61 	zs.avail_in = srclen;
62 	zs.next_out = dst;
63 	zs.avail_out = *dstlen;
64 	zs.zalloc = zfs_zcalloc;
65 	zs.zfree = zfs_zcfree;
66 
67 	/*
68 	 * Call inflateInit2() specifying a window size of DEF_WBITS
69 	 * with the 6th bit set to indicate that the compression format
70 	 * type (zlib or gzip) should be automatically detected.
71 	 */
72 	if ((err = inflateInit2(&zs, DEF_WBITS | 0x20)) != Z_OK)
73 		return (err);
74 
75 	if ((err = inflate(&zs, Z_FINISH)) != Z_STREAM_END) {
76 		(void) inflateEnd(&zs);
77 		return (err == Z_OK ? Z_BUF_ERROR : err);
78 	}
79 
80 	*dstlen = zs.total_out;
81 	return (inflateEnd(&zs));
82 }
83 
84 static int
85 gzip_decompress(void *s_start, void *d_start, size_t s_len, size_t d_len,
86     int n __unused)
87 {
88 	size_t dstlen = d_len;
89 
90 	ASSERT(d_len >= s_len);
91 
92 	if (z_uncompress(d_start, &dstlen, s_start, s_len) != Z_OK)
93 		return (-1);
94 
95 	return (0);
96 }
97