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linux-next/fs/cramfs/uncompress.c
David VomLehn 98310e581e cramfs: propagate uncompression errors
Decompression errors can arise due to corruption of compressed blocks on
flash or in memory.  This patch propagates errors detected during
decompression back to the block layer.

Signed-off-by: David VomLehn <dvomlehn@cisco.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:05:07 -07:00

78 lines
1.7 KiB
C

/*
* uncompress.c
*
* (C) Copyright 1999 Linus Torvalds
*
* cramfs interfaces to the uncompression library. There's really just
* three entrypoints:
*
* - cramfs_uncompress_init() - called to initialize the thing.
* - cramfs_uncompress_exit() - tell me when you're done
* - cramfs_uncompress_block() - uncompress a block.
*
* NOTE NOTE NOTE! The uncompression is entirely single-threaded. We
* only have one stream, and we'll initialize it only once even if it
* then is used by multiple filesystems.
*/
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/vmalloc.h>
#include <linux/zlib.h>
#include <linux/cramfs_fs.h>
static z_stream stream;
static int initialized;
/* Returns length of decompressed data. */
int cramfs_uncompress_block(void *dst, int dstlen, void *src, int srclen)
{
int err;
stream.next_in = src;
stream.avail_in = srclen;
stream.next_out = dst;
stream.avail_out = dstlen;
err = zlib_inflateReset(&stream);
if (err != Z_OK) {
printk("zlib_inflateReset error %d\n", err);
zlib_inflateEnd(&stream);
zlib_inflateInit(&stream);
}
err = zlib_inflate(&stream, Z_FINISH);
if (err != Z_STREAM_END)
goto err;
return stream.total_out;
err:
printk("Error %d while decompressing!\n", err);
printk("%p(%d)->%p(%d)\n", src, srclen, dst, dstlen);
return -EIO;
}
int cramfs_uncompress_init(void)
{
if (!initialized++) {
stream.workspace = vmalloc(zlib_inflate_workspacesize());
if ( !stream.workspace ) {
initialized = 0;
return -ENOMEM;
}
stream.next_in = NULL;
stream.avail_in = 0;
zlib_inflateInit(&stream);
}
return 0;
}
void cramfs_uncompress_exit(void)
{
if (!--initialized) {
zlib_inflateEnd(&stream);
vfree(stream.workspace);
}
}