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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@squashfs.org.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.
*
* decompressor.c
*/
#include <linux/types.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/buffer_head.h>
#include "squashfs_fs.h"
#include "squashfs_fs_sb.h"
#include "decompressor.h"
#include "squashfs.h"
/*
* This file (and decompressor.h) implements a decompressor framework for
* Squashfs, allowing multiple decompressors to be easily supported
*/
static const struct squashfs_decompressor squashfs_lzma_unsupported_comp_ops = {
NULL, NULL, NULL, LZMA_COMPRESSION, "lzma", 0
};
#ifndef CONFIG_SQUASHFS_LZO
static const struct squashfs_decompressor squashfs_lzo_comp_ops = {
NULL, NULL, NULL, LZO_COMPRESSION, "lzo", 0
};
#endif
#ifndef CONFIG_SQUASHFS_XZ
static const struct squashfs_decompressor squashfs_xz_comp_ops = {
NULL, NULL, NULL, XZ_COMPRESSION, "xz", 0
};
#endif
static const struct squashfs_decompressor squashfs_unknown_comp_ops = {
NULL, NULL, NULL, 0, "unknown", 0
};
static const struct squashfs_decompressor *decompressor[] = {
&squashfs_zlib_comp_ops,
&squashfs_lzo_comp_ops,
&squashfs_xz_comp_ops,
&squashfs_lzma_unsupported_comp_ops,
&squashfs_unknown_comp_ops
};
const struct squashfs_decompressor *squashfs_lookup_decompressor(int id)
{
int i;
for (i = 0; decompressor[i]->id; i++)
if (id == decompressor[i]->id)
break;
return decompressor[i];
}
void *squashfs_decompressor_init(struct super_block *sb, unsigned short flags)
{
struct squashfs_sb_info *msblk = sb->s_fs_info;
void *strm, *buffer = NULL;
int length = 0;
/*
* Read decompressor specific options from file system if present
*/
if (SQUASHFS_COMP_OPTS(flags)) {
buffer = kmalloc(PAGE_CACHE_SIZE, GFP_KERNEL);
if (buffer == NULL)
return ERR_PTR(-ENOMEM);
length = squashfs_read_data(sb, &buffer,
sizeof(struct squashfs_super_block), 0, NULL,
PAGE_CACHE_SIZE, 1);
if (length < 0) {
strm = ERR_PTR(length);
goto finished;
}
}
strm = msblk->decompressor->init(msblk, buffer, length);
finished:
kfree(buffer);
return strm;
}
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