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/*
* Squashfs - a compressed read only filesystem for Linux
*
* Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
* Phillip Lougher <phillip@lougher.demon.co.uk>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2,
* or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* lzma_wrapper.c
*/
#include <asm/unaligned.h>
#include <linux/buffer_head.h>
#include <linux/mutex.h>
#include <linux/vmalloc.h>
#include <linux/decompress/unlzma.h>
#include "squashfs_fs.h"
#include "squashfs_fs_sb.h"
#include "squashfs_fs_i.h"
#include "squashfs.h"
#include "decompressor.h"
struct squashfs_lzma {
void *input;
void *output;
};
/* decompress_unlzma.c is currently non re-entrant... */
DEFINE_MUTEX(lzma_mutex);
/* decompress_unlzma.c doesn't provide any context in its callbacks... */
static int lzma_error;
static void error(char *m)
{
ERROR("unlzma error: %s\n", m);
lzma_error = 1;
}
static void *lzma_init(struct squashfs_sb_info *msblk)
{
struct squashfs_lzma *stream = kzalloc(sizeof(*stream), GFP_KERNEL);
if (stream == NULL)
goto failed;
stream->input = vmalloc(msblk->block_size);
if (stream->input == NULL)
goto failed;
stream->output = vmalloc(msblk->block_size);
if (stream->output == NULL)
goto failed2;
return stream;
failed2:
vfree(stream->input);
failed:
ERROR("failed to allocate lzma workspace\n");
kfree(stream);
return NULL;
}
static void lzma_free(void *strm)
{
struct squashfs_lzma *stream = strm;
if (stream) {
vfree(stream->input);
vfree(stream->output);
}
kfree(stream);
}
static int lzma_uncompress(struct squashfs_sb_info *msblk, void **buffer,
struct buffer_head **bh, int b, int offset, int length, int srclength,
int pages)
{
struct squashfs_lzma *stream = msblk->stream;
void *buff = stream->input;
int avail, i, bytes = length, res;
mutex_lock(&lzma_mutex);
for (i = 0; i < b; i++) {
wait_on_buffer(bh[i]);
if (!buffer_uptodate(bh[i]))
goto block_release;
avail = min(bytes, msblk->devblksize - offset);
memcpy(buff, bh[i]->b_data + offset, avail);
buff += avail;
bytes -= avail;
offset = 0;
put_bh(bh[i]);
}
lzma_error = 0;
res = unlzma(stream->input, length, NULL, NULL, stream->output, NULL,
error);
if (res || lzma_error)
goto failed;
/* uncompressed size is stored in the LZMA header (5 byte offset) */
res = bytes = get_unaligned_le32(stream->input + 5);
for (i = 0, buff = stream->output; bytes && i < pages; i++) {
avail = min_t(int, bytes, PAGE_CACHE_SIZE);
memcpy(buffer[i], buff, avail);
buff += avail;
bytes -= avail;
}
if (bytes)
goto failed;
mutex_unlock(&lzma_mutex);
return res;
block_release:
for (; i < b; i++)
put_bh(bh[i]);
failed:
mutex_unlock(&lzma_mutex);
ERROR("lzma decompression failed, data probably corrupt\n");
return -EIO;
}
const struct squashfs_decompressor squashfs_lzma_comp_ops = {
.init = lzma_init,
.free = lzma_free,
.decompress = lzma_uncompress,
.id = LZMA_COMPRESSION,
.name = "lzma",
.supported = 1
};
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