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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384// SPDX-License-Identifier: GPL-2.0/* * decompress.c * * Detect the decompression method based on magic number */
#include <linux/decompress/generic.h>
#include <linux/decompress/bunzip2.h>#include <linux/decompress/unlzma.h>#include <linux/decompress/unxz.h>#include <linux/decompress/inflate.h>#include <linux/decompress/unlzo.h>#include <linux/decompress/unlz4.h>#include <linux/decompress/unzstd.h>
#include <linux/types.h>#include <linux/string.h>#include <linux/init.h>#include <linux/printk.h>
#ifndef CONFIG_DECOMPRESS_GZIP# define gunzip NULL#endif#ifndef CONFIG_DECOMPRESS_BZIP2# define bunzip2 NULL#endif#ifndef CONFIG_DECOMPRESS_LZMA# define unlzma NULL#endif#ifndef CONFIG_DECOMPRESS_XZ# define unxz NULL#endif#ifndef CONFIG_DECOMPRESS_LZO# define unlzo NULL#endif#ifndef CONFIG_DECOMPRESS_LZ4# define unlz4 NULL#endif#ifndef CONFIG_DECOMPRESS_ZSTD# define unzstd NULL#endif
struct compress_format { unsigned char magic[2]; const char *name; decompress_fn decompressor;};
static const struct compress_format compressed_formats[] __initconst = { { .magic = {0x1f, 0x8b}, .name = "gzip", .decompressor = gunzip }, { .magic = {0x1f, 0x9e}, .name = "gzip", .decompressor = gunzip }, { .magic = {0x42, 0x5a}, .name = "bzip2", .decompressor = bunzip2 }, { .magic = {0x5d, 0x00}, .name = "lzma", .decompressor = unlzma }, { .magic = {0xfd, 0x37}, .name = "xz", .decompressor = unxz }, { .magic = {0x89, 0x4c}, .name = "lzo", .decompressor = unlzo }, { .magic = {0x02, 0x21}, .name = "lz4", .decompressor = unlz4 }, { .magic = {0x28, 0xb5}, .name = "zstd", .decompressor = unzstd }, { /* sentinel */ }};
decompress_fn __init decompress_method(const unsigned char *inbuf, long len, const char **name){ const struct compress_format *cf;
if (len < 2) { if (name) *name = NULL; return NULL; /* Need at least this much... */ }
pr_debug("Compressed data magic: %#.2x %#.2x\n", inbuf[0], inbuf[1]);
for (cf = compressed_formats; cf->name; cf++) if (!memcmp(inbuf, cf->magic, 2)) break;
if (name) *name = cf->name; return cf->decompressor;}