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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 <hpa@zytor.com>
This commit is contained in:
H. Peter Anvin 2009-01-08 15:14:17 -08:00
parent 6c11b12ac6
commit 889c92d21d
5 changed files with 72 additions and 67 deletions
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3
include/linux/decompress/generic.h
View File

@ -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

38
init/do_mounts_rd.c
View File

@ -12,9 +12,6 @@
#include <linux/decompress/generic.h>
#include <linux/decompress/bunzip2.h>
#include <linux/decompress/unlzma.h>
#include <linux/decompress/inflate.h>
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 */

39
init/initramfs.c
View File

@ -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 <linux/decompress/bunzip2.h>
#include <linux/decompress/unlzma.h>
#include <linux/decompress/inflate.h>
#include <linux/decompress/generic.h>
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;

9
lib/Makefile
View File

@ -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

50
lib/decompress.c Normal file
View File

@ -0,0 +1,50 @@
/*
* 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/inflate.h>
#include <linux/types.h>
#include <linux/string.h>
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;
}