// 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 <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_LZ4 static const struct squashfs_decompressor squashfs_lz4_comp_ops = { NULL, NULL, NULL, NULL, LZ4_COMPRESSION, "lz4", 0 }; #endif #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 #ifndef CONFIG_SQUASHFS_ZSTD static 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 = squashfs_decompressor_create(msblk, comp_opts); if (IS_ERR(stream)) kfree(comp_opts); return stream; }