142 lines · c
1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * Squashfs - a compressed read only filesystem for Linux4 *5 * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 20096 * Phillip Lougher <phillip@squashfs.org.uk>7 *8 * decompressor.c9 */10 11#include <linux/types.h>12#include <linux/mutex.h>13#include <linux/slab.h>14 15#include "squashfs_fs.h"16#include "squashfs_fs_sb.h"17#include "decompressor.h"18#include "squashfs.h"19#include "page_actor.h"20 21/*22 * This file (and decompressor.h) implements a decompressor framework for23 * Squashfs, allowing multiple decompressors to be easily supported24 */25 26static const struct squashfs_decompressor squashfs_lzma_unsupported_comp_ops = {27 NULL, NULL, NULL, NULL, LZMA_COMPRESSION, "lzma", 028};29 30#ifndef CONFIG_SQUASHFS_LZ431static const struct squashfs_decompressor squashfs_lz4_comp_ops = {32 NULL, NULL, NULL, NULL, LZ4_COMPRESSION, "lz4", 033};34#endif35 36#ifndef CONFIG_SQUASHFS_LZO37static const struct squashfs_decompressor squashfs_lzo_comp_ops = {38 NULL, NULL, NULL, NULL, LZO_COMPRESSION, "lzo", 039};40#endif41 42#ifndef CONFIG_SQUASHFS_XZ43static const struct squashfs_decompressor squashfs_xz_comp_ops = {44 NULL, NULL, NULL, NULL, XZ_COMPRESSION, "xz", 045};46#endif47 48#ifndef CONFIG_SQUASHFS_ZLIB49static const struct squashfs_decompressor squashfs_zlib_comp_ops = {50 NULL, NULL, NULL, NULL, ZLIB_COMPRESSION, "zlib", 051};52#endif53 54#ifndef CONFIG_SQUASHFS_ZSTD55static const struct squashfs_decompressor squashfs_zstd_comp_ops = {56 NULL, NULL, NULL, NULL, ZSTD_COMPRESSION, "zstd", 057};58#endif59 60static const struct squashfs_decompressor squashfs_unknown_comp_ops = {61 NULL, NULL, NULL, NULL, 0, "unknown", 062};63 64static const struct squashfs_decompressor *decompressor[] = {65 &squashfs_zlib_comp_ops,66 &squashfs_lz4_comp_ops,67 &squashfs_lzo_comp_ops,68 &squashfs_xz_comp_ops,69 &squashfs_lzma_unsupported_comp_ops,70 &squashfs_zstd_comp_ops,71 &squashfs_unknown_comp_ops72};73 74 75const struct squashfs_decompressor *squashfs_lookup_decompressor(int id)76{77 int i;78 79 for (i = 0; decompressor[i]->id; i++)80 if (id == decompressor[i]->id)81 break;82 83 return decompressor[i];84}85 86 87static void *get_comp_opts(struct super_block *sb, unsigned short flags)88{89 struct squashfs_sb_info *msblk = sb->s_fs_info;90 void *buffer = NULL, *comp_opts;91 struct squashfs_page_actor *actor = NULL;92 int length = 0;93 94 /*95 * Read decompressor specific options from file system if present96 */97 if (SQUASHFS_COMP_OPTS(flags)) {98 buffer = kmalloc(PAGE_SIZE, GFP_KERNEL);99 if (buffer == NULL) {100 comp_opts = ERR_PTR(-ENOMEM);101 goto out;102 }103 104 actor = squashfs_page_actor_init(&buffer, 1, 0);105 if (actor == NULL) {106 comp_opts = ERR_PTR(-ENOMEM);107 goto out;108 }109 110 length = squashfs_read_data(sb,111 sizeof(struct squashfs_super_block), 0, NULL, actor);112 113 if (length < 0) {114 comp_opts = ERR_PTR(length);115 goto out;116 }117 }118 119 comp_opts = squashfs_comp_opts(msblk, buffer, length);120 121out:122 kfree(actor);123 kfree(buffer);124 return comp_opts;125}126 127 128void *squashfs_decompressor_setup(struct super_block *sb, unsigned short flags)129{130 struct squashfs_sb_info *msblk = sb->s_fs_info;131 void *stream, *comp_opts = get_comp_opts(sb, flags);132 133 if (IS_ERR(comp_opts))134 return comp_opts;135 136 stream = msblk->thread_ops->create(msblk, comp_opts);137 if (IS_ERR(stream))138 kfree(comp_opts);139 140 return stream;141}142