1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Squashfs - a compressed read only filesystem for Linux 4 * 5 * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 6 * Phillip Lougher <phillip@squashfs.org.uk> 7 * 8 * decompressor.c 9 */ 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 for 23 * Squashfs, allowing multiple decompressors to be easily supported 24 */ 25 26 static const struct squashfs_decompressor squashfs_lzma_unsupported_comp_ops = { 27 NULL, NULL, NULL, NULL, LZMA_COMPRESSION, "lzma", 0 28 }; 29 30 #ifndef CONFIG_SQUASHFS_LZ4 31 static const struct squashfs_decompressor squashfs_lz4_comp_ops = { 32 NULL, NULL, NULL, NULL, LZ4_COMPRESSION, "lz4", 0 33 }; 34 #endif 35 36 #ifndef CONFIG_SQUASHFS_LZO 37 static const struct squashfs_decompressor squashfs_lzo_comp_ops = { 38 NULL, NULL, NULL, NULL, LZO_COMPRESSION, "lzo", 0 39 }; 40 #endif 41 42 #ifndef CONFIG_SQUASHFS_XZ 43 static const struct squashfs_decompressor squashfs_xz_comp_ops = { 44 NULL, NULL, NULL, NULL, XZ_COMPRESSION, "xz", 0 45 }; 46 #endif 47 48 #ifndef CONFIG_SQUASHFS_ZLIB 49 static const struct squashfs_decompressor squashfs_zlib_comp_ops = { 50 NULL, NULL, NULL, NULL, ZLIB_COMPRESSION, "zlib", 0 51 }; 52 #endif 53 54 #ifndef CONFIG_SQUASHFS_ZSTD 55 static const struct squashfs_decompressor squashfs_zstd_comp_ops = { 56 NULL, NULL, NULL, NULL, ZSTD_COMPRESSION, "zstd", 0 57 }; 58 #endif 59 60 static const struct squashfs_decompressor squashfs_unknown_comp_ops = { 61 NULL, NULL, NULL, NULL, 0, "unknown", 0 62 }; 63 64 static 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_ops 72 }; 73 74 75 const 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 87 static 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 present 96 */ 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); 120 121 out: 122 kfree(actor); 123 kfree(buffer); 124 return comp_opts; 125 } 126 127 128 void *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