1/*
 2 * decompress.c
 3 *
 4 * Detect the decompression method based on magic number
 5 */
 6
 7#include <linux/decompress/generic.h>
 8
 9#include <linux/decompress/bunzip2.h>
10#include <linux/decompress/unlzma.h>
11#include <linux/decompress/unxz.h>
12#include <linux/decompress/inflate.h>
13#include <linux/decompress/unlzo.h>
14#include <linux/decompress/unlz4.h>
15
16#include <linux/types.h>
17#include <linux/string.h>
18#include <linux/init.h>
19#include <linux/printk.h>
20
21#ifndef CONFIG_DECOMPRESS_GZIP
22# define gunzip NULL
23#endif
24#ifndef CONFIG_DECOMPRESS_BZIP2
25# define bunzip2 NULL
26#endif
27#ifndef CONFIG_DECOMPRESS_LZMA
28# define unlzma NULL
29#endif
30#ifndef CONFIG_DECOMPRESS_XZ
31# define unxz NULL
32#endif
33#ifndef CONFIG_DECOMPRESS_LZO
34# define unlzo NULL
35#endif
36#ifndef CONFIG_DECOMPRESS_LZ4
37# define unlz4 NULL
38#endif
39
40struct compress_format {
41	unsigned char magic[2];
42	const char *name;
43	decompress_fn decompressor;
44};
45
46static const struct compress_format compressed_formats[] __initconst = {
47	{ {037, 0213}, "gzip", gunzip },
48	{ {037, 0236}, "gzip", gunzip },
49	{ {0x42, 0x5a}, "bzip2", bunzip2 },
50	{ {0x5d, 0x00}, "lzma", unlzma },
51	{ {0xfd, 0x37}, "xz", unxz },
52	{ {0x89, 0x4c}, "lzo", unlzo },
53	{ {0x02, 0x21}, "lz4", unlz4 },
54	{ {0, 0}, NULL, NULL }
55};
56
57decompress_fn __init decompress_method(const unsigned char *inbuf, int len,
58				const char **name)
59{
60	const struct compress_format *cf;
61
62	if (len < 2)
 
 
63		return NULL;	/* Need at least this much... */
 
64
65	pr_debug("Compressed data magic: %#.2x %#.2x\n", inbuf[0], inbuf[1]);
66
67	for (cf = compressed_formats; cf->name; cf++) {
68		if (!memcmp(inbuf, cf->magic, 2))
69			break;
70
71	}
72	if (name)
73		*name = cf->name;
74	return cf->decompressor;
75}

 1// SPDX-License-Identifier: GPL-2.0
 2/*
 3 * decompress.c
 4 *
 5 * Detect the decompression method based on magic number
 6 */
 7
 8#include <linux/decompress/generic.h>
 9
10#include <linux/decompress/bunzip2.h>
11#include <linux/decompress/unlzma.h>
12#include <linux/decompress/unxz.h>
13#include <linux/decompress/inflate.h>
14#include <linux/decompress/unlzo.h>
15#include <linux/decompress/unlz4.h>
16
17#include <linux/types.h>
18#include <linux/string.h>
19#include <linux/init.h>
20#include <linux/printk.h>
21
22#ifndef CONFIG_DECOMPRESS_GZIP
23# define gunzip NULL
24#endif
25#ifndef CONFIG_DECOMPRESS_BZIP2
26# define bunzip2 NULL
27#endif
28#ifndef CONFIG_DECOMPRESS_LZMA
29# define unlzma NULL
30#endif
31#ifndef CONFIG_DECOMPRESS_XZ
32# define unxz NULL
33#endif
34#ifndef CONFIG_DECOMPRESS_LZO
35# define unlzo NULL
36#endif
37#ifndef CONFIG_DECOMPRESS_LZ4
38# define unlz4 NULL
39#endif
40
41struct compress_format {
42	unsigned char magic[2];
43	const char *name;
44	decompress_fn decompressor;
45};
46
47static const struct compress_format compressed_formats[] __initconst = {
48	{ {0x1f, 0x8b}, "gzip", gunzip },
49	{ {0x1f, 0x9e}, "gzip", gunzip },
50	{ {0x42, 0x5a}, "bzip2", bunzip2 },
51	{ {0x5d, 0x00}, "lzma", unlzma },
52	{ {0xfd, 0x37}, "xz", unxz },
53	{ {0x89, 0x4c}, "lzo", unlzo },
54	{ {0x02, 0x21}, "lz4", unlz4 },
55	{ {0, 0}, NULL, NULL }
56};
57
58decompress_fn __init decompress_method(const unsigned char *inbuf, long len,
59				const char **name)
60{
61	const struct compress_format *cf;
62
63	if (len < 2) {
64		if (name)
65			*name = NULL;
66		return NULL;	/* Need at least this much... */
67	}
68
69	pr_debug("Compressed data magic: %#.2x %#.2x\n", inbuf[0], inbuf[1]);
70
71	for (cf = compressed_formats; cf->name; cf++) {
72		if (!memcmp(inbuf, cf->magic, 2))
73			break;
74
75	}
76	if (name)
77		*name = cf->name;
78	return cf->decompressor;
79}