cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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decompress.c (1869B)

      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#include <linux/decompress/unzstd.h>
     17
     18#include <linux/types.h>
     19#include <linux/string.h>
     20#include <linux/init.h>
     21#include <linux/printk.h>
     22
     23#ifndef CONFIG_DECOMPRESS_GZIP
     24# define gunzip NULL
     25#endif
     26#ifndef CONFIG_DECOMPRESS_BZIP2
     27# define bunzip2 NULL
     28#endif
     29#ifndef CONFIG_DECOMPRESS_LZMA
     30# define unlzma NULL
     31#endif
     32#ifndef CONFIG_DECOMPRESS_XZ
     33# define unxz NULL
     34#endif
     35#ifndef CONFIG_DECOMPRESS_LZO
     36# define unlzo NULL
     37#endif
     38#ifndef CONFIG_DECOMPRESS_LZ4
     39# define unlz4 NULL
     40#endif
     41#ifndef CONFIG_DECOMPRESS_ZSTD
     42# define unzstd NULL
     43#endif
     44
     45struct compress_format {
     46	unsigned char magic[2];
     47	const char *name;
     48	decompress_fn decompressor;
     49};
     50
     51static const struct compress_format compressed_formats[] __initconst = {
     52	{ {0x1f, 0x8b}, "gzip", gunzip },
     53	{ {0x1f, 0x9e}, "gzip", gunzip },
     54	{ {0x42, 0x5a}, "bzip2", bunzip2 },
     55	{ {0x5d, 0x00}, "lzma", unlzma },
     56	{ {0xfd, 0x37}, "xz", unxz },
     57	{ {0x89, 0x4c}, "lzo", unlzo },
     58	{ {0x02, 0x21}, "lz4", unlz4 },
     59	{ {0x28, 0xb5}, "zstd", unzstd },
     60	{ {0, 0}, NULL, NULL }
     61};
     62
     63decompress_fn __init decompress_method(const unsigned char *inbuf, long len,
     64				const char **name)
     65{
     66	const struct compress_format *cf;
     67
     68	if (len < 2) {
     69		if (name)
     70			*name = NULL;
     71		return NULL;	/* Need at least this much... */
     72	}
     73
     74	pr_debug("Compressed data magic: %#.2x %#.2x\n", inbuf[0], inbuf[1]);
     75
     76	for (cf = compressed_formats; cf->name; cf++) {
     77		if (!memcmp(inbuf, cf->magic, 2))
     78			break;
     79
     80	}
     81	if (name)
     82		*name = cf->name;
     83	return cf->decompressor;
     84}