4 * Detect the decompression method based on magic number
7 #include <linux/decompress/generic.h>
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>
16 #include <linux/types.h>
17 #include <linux/string.h>
18 #include <linux/init.h>
19 #include <linux/printk.h>
21 #ifndef CONFIG_DECOMPRESS_GZIP
24 #ifndef CONFIG_DECOMPRESS_BZIP2
27 #ifndef CONFIG_DECOMPRESS_LZMA
30 #ifndef CONFIG_DECOMPRESS_XZ
33 #ifndef CONFIG_DECOMPRESS_LZO
36 #ifndef CONFIG_DECOMPRESS_LZ4
40 struct compress_format {
41 unsigned char magic[2];
43 decompress_fn decompressor;
46 static const struct compress_format compressed_formats[] __initconst = {
47 { {0x1f, 0x8b}, "gzip", gunzip },
48 { {0x1f, 0x9e}, "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 }
57 decompress_fn __init decompress_method(const unsigned char *inbuf, long len,
60 const struct compress_format *cf;
65 return NULL; /* Need at least this much... */
68 pr_debug("Compressed data magic: %#.2x %#.2x\n", inbuf[0], inbuf[1]);
70 for (cf = compressed_formats; cf->name; cf++) {
71 if (!memcmp(inbuf, cf->magic, 2))
77 return cf->decompressor;