/* * 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_LZOstatic const struct squashfs_decompressor squashfs_lzo_comp_ops = {	NULL, NULL, NULL, LZO_COMPRESSION, "lzo", 0};#endif #ifndef CONFIG_SQUASHFS_XZstatic const struct squashfs_decompressor squashfs_xz_comp_ops = {	NULL, NULL, NULL, XZ_COMPRESSION, "xz", 0};#endif #ifndef CONFIG_SQUASHFS_ZLIBstatic const struct squashfs_decompressor squashfs_zlib_comp_ops = {	NULL, NULL, NULL, ZLIB_COMPRESSION, "zlib", 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;}