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// 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;
}
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