From 889c92d21db40be0b7d22a59395060237895bb85 Mon Sep 17 00:00:00 2001 From: "H. Peter Anvin" Date: Thu, 8 Jan 2009 15:14:17 -0800 Subject: [PATCH] bzip2/lzma: centralize format detection Centralize the compression format detection to a common routine in the lib directory, and use it for both initramfs and initrd. Signed-off-by: H. Peter Anvin --- include/linux/decompress/generic.h | 3 +++ init/do_mounts_rd.c | 38 ++++++----------------------- init/initramfs.c | 39 ++++++----------------------- lib/Makefile | 9 ++++--- lib/decompress.c | 50 ++++++++++++++++++++++++++++++++++++++ 5 files changed, 72 insertions(+), 67 deletions(-) create mode 100644 lib/decompress.c diff --git a/include/linux/decompress/generic.h b/include/linux/decompress/generic.h index f847f51..6dfb856 100644 --- a/include/linux/decompress/generic.h +++ b/include/linux/decompress/generic.h @@ -26,5 +26,8 @@ typedef int (*decompress_fn) (unsigned char *inbuf, int len, *fill should be called (repeatedly...) to read data, at most IOBUF_SIZE */ +/* Utility routine to detect the decompression method */ +decompress_fn decompress_method(const unsigned char *inbuf, int len, + const char **name); #endif diff --git a/init/do_mounts_rd.c b/init/do_mounts_rd.c index 9c9d7db..a06ed4f 100644 --- a/init/do_mounts_rd.c +++ b/init/do_mounts_rd.c @@ -12,9 +12,6 @@ #include -#include -#include -#include int __initdata rd_prompt = 1;/* 1 = prompt for RAM disk, 0 = don't prompt */ @@ -49,24 +46,6 @@ static int __init crd_load(int in_fd, int out_fd, decompress_fn deco); * cramfs * gzip */ -static const struct compress_format { - unsigned char magic[2]; - const char *name; - decompress_fn decompressor; -} compressed_formats[] = { -#ifdef CONFIG_RD_GZIP - { {037, 0213}, "gzip", gunzip }, - { {037, 0236}, "gzip", gunzip }, -#endif -#ifdef CONFIG_RD_BZIP2 - { {0x42, 0x5a}, "bzip2", bunzip2 }, -#endif -#ifdef CONFIG_RD_LZMA - { {0x5d, 0x00}, "lzma", unlzma }, -#endif - { {0, 0}, NULL, NULL } -}; - static int __init identify_ramdisk_image(int fd, int start_block, decompress_fn *decompressor) { @@ -77,7 +56,7 @@ identify_ramdisk_image(int fd, int start_block, decompress_fn *decompressor) struct cramfs_super *cramfsb; int nblocks = -1; unsigned char *buf; - const struct compress_format *cf; + const char *compress_name; buf = kmalloc(size, GFP_KERNEL); if (!buf) @@ -95,15 +74,12 @@ identify_ramdisk_image(int fd, int start_block, decompress_fn *decompressor) sys_lseek(fd, start_block * BLOCK_SIZE, 0); sys_read(fd, buf, size); - for (cf = compressed_formats; cf->decompressor; cf++) { - if (buf[0] == cf->magic[0] && buf[1] == cf->magic[1]) { - printk(KERN_NOTICE - "RAMDISK: %s image found at block %d\n", - cf->name, start_block); - *decompressor = cf->decompressor; - nblocks = 0; - goto done; - } + *decompressor = decompress_method(buf, size, &compress_name); + if (*decompressor) { + printk(KERN_NOTICE "RAMDISK: %s image found at block %d\n", + compress_name, start_block); + nblocks = 0; + goto done; } /* romfs is at block zero too */ diff --git a/init/initramfs.c b/init/initramfs.c index a3ba91c..2f42984 100644 --- a/init/initramfs.c +++ b/init/initramfs.c @@ -416,13 +416,13 @@ static int __init flush_buffer(void *bufv, unsigned len) static unsigned my_inptr; /* index of next byte to be processed in inbuf */ -#include -#include -#include +#include static char * __init unpack_to_rootfs(char *buf, unsigned len, int check_only) { int written; + decompress_fn decompress; + dry_run = check_only; header_buf = kmalloc(110, GFP_KERNEL); symlink_buf = kmalloc(PATH_MAX + N_ALIGN(PATH_MAX) + 1, GFP_KERNEL); @@ -450,35 +450,10 @@ static char * __init unpack_to_rootfs(char *buf, unsigned len, int check_only) continue; } this_header = 0; -#ifdef CONFIG_RD_GZIP - if (!gunzip(buf, len, NULL, flush_buffer, NULL, - &my_inptr, error) && - message == NULL) - goto ok; -#endif - -#ifdef CONFIG_RD_BZIP2 - message = NULL; /* Zero out message, or else cpio will - think an error has already occured */ - if (!bunzip2(buf, len, NULL, flush_buffer, NULL, - &my_inptr, error) && - message == NULL) { - goto ok; - } -#endif - -#ifdef CONFIG_RD_LZMA - message = NULL; /* Zero out message, or else cpio will - think an error has already occured */ - if (!unlzma(buf, len, NULL, flush_buffer, NULL, - &my_inptr, error) && - message == NULL) { - goto ok; - } -#endif -#if defined CONFIG_RD_GZIP || defined CONFIG_RD_BZIP2 || defined CONFIG_RD_LZMA -ok: -#endif + decompress = decompress_method(buf, len, NULL); + if (decompress) + decompress(buf, len, NULL, flush_buffer, NULL, + &my_inptr, error); if (state != Reset) error("junk in compressed archive"); this_header = saved_offset + my_inptr; diff --git a/lib/Makefile b/lib/Makefile index d9ac5a4..790de7c 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -11,7 +11,8 @@ lib-y := ctype.o string.o vsprintf.o cmdline.o \ rbtree.o radix-tree.o dump_stack.o \ idr.o int_sqrt.o extable.o prio_tree.o \ sha1.o irq_regs.o reciprocal_div.o argv_split.o \ - proportions.o prio_heap.o ratelimit.o show_mem.o is_single_threaded.o + proportions.o prio_heap.o ratelimit.o show_mem.o \ + is_single_threaded.o decompress.o lib-$(CONFIG_MMU) += ioremap.o lib-$(CONFIG_SMP) += cpumask.o @@ -65,9 +66,9 @@ obj-$(CONFIG_REED_SOLOMON) += reed_solomon/ obj-$(CONFIG_LZO_COMPRESS) += lzo/ obj-$(CONFIG_LZO_DECOMPRESS) += lzo/ -obj-$(CONFIG_DECOMPRESS_GZIP) += decompress_inflate.o -obj-$(CONFIG_DECOMPRESS_BZIP2) += decompress_bunzip2.o -obj-$(CONFIG_DECOMPRESS_LZMA) += decompress_unlzma.o +lib-$(CONFIG_DECOMPRESS_GZIP) += decompress_inflate.o +lib-$(CONFIG_DECOMPRESS_BZIP2) += decompress_bunzip2.o +lib-$(CONFIG_DECOMPRESS_LZMA) += decompress_unlzma.o obj-$(CONFIG_TEXTSEARCH) += textsearch.o obj-$(CONFIG_TEXTSEARCH_KMP) += ts_kmp.o diff --git a/lib/decompress.c b/lib/decompress.c new file mode 100644 index 0000000..edac55c --- /dev/null +++ b/lib/decompress.c @@ -0,0 +1,50 @@ +/* + * decompress.c + * + * Detect the decompression method based on magic number + */ + +#include + +#include +#include +#include + +#include +#include + +static const struct compress_format { + unsigned char magic[2]; + const char *name; + decompress_fn decompressor; +} compressed_formats[] = { +#ifdef CONFIG_DECOMPRESS_GZIP + { {037, 0213}, "gzip", gunzip }, + { {037, 0236}, "gzip", gunzip }, +#endif +#ifdef CONFIG_DECOMPRESS_BZIP2 + { {0x42, 0x5a}, "bzip2", bunzip2 }, +#endif +#ifdef CONFIG_DECOMPRESS_LZMA + { {0x5d, 0x00}, "lzma", unlzma }, +#endif + { {0, 0}, NULL, NULL } +}; + +decompress_fn decompress_method(const unsigned char *inbuf, int len, + const char **name) +{ + const struct compress_format *cf; + + if (len < 2) + return NULL; /* Need at least this much... */ + + for (cf = compressed_formats; cf->decompressor; cf++) { + if (!memcmp(inbuf, cf->magic, 2)) + break; + + } + if (name) + *name = cf->name; + return cf->decompressor; +} -- 1.8.2.3