// SPDX-License-Identifier: GPL-2.0-or-later/* * Squashfs - a compressed read only filesystem for Linux * * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 * Phillip Lougher <phillip@squashfs.org.uk> * * decompressor.c */ #include <linux/types.h>#include <linux/mutex.h>#include <linux/slab.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_LZ4static const struct squashfs_decompressor squashfs_lz4_comp_ops = {	NULL, NULL, NULL, NULL, LZ4_COMPRESSION, "lz4", 0};#endif #ifndef CONFIG_SQUASHFS_LZOstatic const struct squashfs_decompressor squashfs_lzo_comp_ops = {	NULL, NULL, NULL, NULL, LZO_COMPRESSION, "lzo", 0};#endif #ifndef CONFIG_SQUASHFS_XZstatic const struct squashfs_decompressor squashfs_xz_comp_ops = {	NULL, NULL, NULL, NULL, XZ_COMPRESSION, "xz", 0};#endif #ifndef CONFIG_SQUASHFS_ZLIBstatic const struct squashfs_decompressor squashfs_zlib_comp_ops = {	NULL, NULL, NULL, NULL, ZLIB_COMPRESSION, "zlib", 0};#endif #ifndef CONFIG_SQUASHFS_ZSTDstatic const struct squashfs_decompressor squashfs_zstd_comp_ops = {	NULL, NULL, NULL, NULL, ZSTD_COMPRESSION, "zstd", 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_lz4_comp_ops,	&squashfs_lzo_comp_ops,	&squashfs_xz_comp_ops,	&squashfs_lzma_unsupported_comp_ops,	&squashfs_zstd_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_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 = msblk->thread_ops->create(msblk, comp_opts);	if (IS_ERR(stream))		kfree(comp_opts); 	return stream;}