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Commit 889c92d2 authored by H. Peter Anvin's avatar H. Peter Anvin
Browse files

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: default avatarH. Peter Anvin <hpa@zytor.com>
parent 6c11b12a

include/linux/decompress/generic.h

+3 −0
Original line number Diff line number Diff line
@@ -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

init/do_mounts_rd.c

+7 −31
Original line number Diff line number Diff line
@@ -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)
@@ -95,16 +74,13 @@ 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;

	*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 */

	if (romfsb->word0 == ROMSB_WORD0 &&

init/initramfs.c

+7 −32
Original line number Diff line number Diff line
@@ -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;

lib/Makefile

+5 −4
Original line number Diff line number Diff line
@@ -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

lib/decompress.c

0 → 100644
+50 −0
Original line number Diff line number Diff line 
/*

 * 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;

}