mirror of https://gitee.com/openkylin/linux.git
142 lines
3.5 KiB
C
142 lines
3.5 KiB
C
/*
|
|
* 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"
|
|
#include "page_actor.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, NULL, LZMA_COMPRESSION, "lzma", 0
|
|
};
|
|
|
|
#ifndef CONFIG_SQUASHFS_LZO
|
|
static const struct squashfs_decompressor squashfs_lzo_comp_ops = {
|
|
NULL, NULL, NULL, NULL, LZO_COMPRESSION, "lzo", 0
|
|
};
|
|
#endif
|
|
|
|
#ifndef CONFIG_SQUASHFS_XZ
|
|
static const struct squashfs_decompressor squashfs_xz_comp_ops = {
|
|
NULL, NULL, NULL, NULL, XZ_COMPRESSION, "xz", 0
|
|
};
|
|
#endif
|
|
|
|
#ifndef CONFIG_SQUASHFS_ZLIB
|
|
static const struct squashfs_decompressor squashfs_zlib_comp_ops = {
|
|
NULL, NULL, NULL, NULL, ZLIB_COMPRESSION, "zlib", 0
|
|
};
|
|
#endif
|
|
|
|
static const struct squashfs_decompressor squashfs_unknown_comp_ops = {
|
|
NULL, 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];
|
|
}
|
|
|
|
|
|
static void *get_comp_opts(struct super_block *sb, unsigned short flags)
|
|
{
|
|
struct squashfs_sb_info *msblk = sb->s_fs_info;
|
|
void *buffer = NULL, *comp_opts;
|
|
struct squashfs_page_actor *actor = 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) {
|
|
comp_opts = ERR_PTR(-ENOMEM);
|
|
goto out;
|
|
}
|
|
|
|
actor = squashfs_page_actor_init(&buffer, 1, 0);
|
|
if (actor == NULL) {
|
|
comp_opts = ERR_PTR(-ENOMEM);
|
|
goto out;
|
|
}
|
|
|
|
length = squashfs_read_data(sb,
|
|
sizeof(struct squashfs_super_block), 0, NULL, actor);
|
|
|
|
if (length < 0) {
|
|
comp_opts = ERR_PTR(length);
|
|
goto out;
|
|
}
|
|
}
|
|
|
|
comp_opts = squashfs_comp_opts(msblk, buffer, length);
|
|
|
|
out:
|
|
kfree(actor);
|
|
kfree(buffer);
|
|
return comp_opts;
|
|
}
|
|
|
|
|
|
void *squashfs_decompressor_setup(struct super_block *sb, unsigned short flags)
|
|
{
|
|
struct squashfs_sb_info *msblk = sb->s_fs_info;
|
|
void *stream, *comp_opts = get_comp_opts(sb, flags);
|
|
|
|
if (IS_ERR(comp_opts))
|
|
return comp_opts;
|
|
|
|
stream = squashfs_decompressor_create(msblk, comp_opts);
|
|
if (IS_ERR(stream))
|
|
kfree(comp_opts);
|
|
|
|
return stream;
|
|
}
|