// 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/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 struct compress_format { unsigned char magic[2]; const char *name; decompress_fn decompressor; }; static const struct compress_format compressed_formats[] __initconst = { { {0x1f, 0x8b}, "gzip", gunzip }, { {0x1f, 0x9e}, "gzip", gunzip }, { {0x42, 0x5a}, "bzip2", bunzip2 }, { {0x5d, 0x00}, "lzma", unlzma }, { {0xfd, 0x37}, "xz", unxz }, { {0x89, 0x4c}, "lzo", unlzo }, { {0x02, 0x21}, "lz4", unlz4 }, { {0, 0}, NULL, NULL } }; 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; }