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4c0f0bb2 PL |
1 | /* |
2 | * Squashfs - a compressed read only filesystem for Linux | |
3 | * | |
4 | * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 | |
d7f2ff67 | 5 | * Phillip Lougher <phillip@squashfs.org.uk> |
4c0f0bb2 PL |
6 | * |
7 | * This program is free software; you can redistribute it and/or | |
8 | * modify it under the terms of the GNU General Public License | |
9 | * as published by the Free Software Foundation; either version 2, | |
10 | * or (at your option) any later version. | |
11 | * | |
12 | * This program is distributed in the hope that it will be useful, | |
13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | * GNU General Public License for more details. | |
16 | * | |
17 | * You should have received a copy of the GNU General Public License | |
18 | * along with this program; if not, write to the Free Software | |
19 | * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. | |
20 | * | |
21 | * decompressor.c | |
22 | */ | |
23 | ||
24 | #include <linux/types.h> | |
25 | #include <linux/mutex.h> | |
b7fc0ff0 | 26 | #include <linux/slab.h> |
4c0f0bb2 PL |
27 | #include <linux/buffer_head.h> |
28 | ||
29 | #include "squashfs_fs.h" | |
30 | #include "squashfs_fs_sb.h" | |
4c0f0bb2 PL |
31 | #include "decompressor.h" |
32 | #include "squashfs.h" | |
846b730e | 33 | #include "page_actor.h" |
4c0f0bb2 PL |
34 | |
35 | /* | |
36 | * This file (and decompressor.h) implements a decompressor framework for | |
37 | * Squashfs, allowing multiple decompressors to be easily supported | |
38 | */ | |
39 | ||
dc325678 | 40 | static const struct squashfs_decompressor squashfs_lzma_unsupported_comp_ops = { |
9508c6b9 | 41 | NULL, NULL, NULL, NULL, LZMA_COMPRESSION, "lzma", 0 |
dc325678 PL |
42 | }; |
43 | ||
62421645 PL |
44 | #ifndef CONFIG_SQUASHFS_LZ4 |
45 | static const struct squashfs_decompressor squashfs_lz4_comp_ops = { | |
46 | NULL, NULL, NULL, NULL, LZ4_COMPRESSION, "lz4", 0 | |
47 | }; | |
48 | #endif | |
49 | ||
79cb8ced | 50 | #ifndef CONFIG_SQUASHFS_LZO |
01a678c5 | 51 | static const struct squashfs_decompressor squashfs_lzo_comp_ops = { |
9508c6b9 | 52 | NULL, NULL, NULL, NULL, LZO_COMPRESSION, "lzo", 0 |
dc325678 | 53 | }; |
79cb8ced | 54 | #endif |
dc325678 | 55 | |
7a43ae52 PL |
56 | #ifndef CONFIG_SQUASHFS_XZ |
57 | static const struct squashfs_decompressor squashfs_xz_comp_ops = { | |
9508c6b9 | 58 | NULL, NULL, NULL, NULL, XZ_COMPRESSION, "xz", 0 |
7a43ae52 PL |
59 | }; |
60 | #endif | |
61 | ||
cc6d3497 PL |
62 | #ifndef CONFIG_SQUASHFS_ZLIB |
63 | static const struct squashfs_decompressor squashfs_zlib_comp_ops = { | |
9508c6b9 | 64 | NULL, NULL, NULL, NULL, ZLIB_COMPRESSION, "zlib", 0 |
cc6d3497 PL |
65 | }; |
66 | #endif | |
67 | ||
87bf54bb SP |
68 | #ifndef CONFIG_SQUASHFS_ZSTD |
69 | static const struct squashfs_decompressor squashfs_zstd_comp_ops = { | |
70 | NULL, NULL, NULL, NULL, ZSTD_COMPRESSION, "zstd", 0 | |
71 | }; | |
72 | #endif | |
73 | ||
4c0f0bb2 | 74 | static const struct squashfs_decompressor squashfs_unknown_comp_ops = { |
9508c6b9 | 75 | NULL, NULL, NULL, NULL, 0, "unknown", 0 |
4c0f0bb2 PL |
76 | }; |
77 | ||
78 | static const struct squashfs_decompressor *decompressor[] = { | |
79 | &squashfs_zlib_comp_ops, | |
62421645 | 80 | &squashfs_lz4_comp_ops, |
79cb8ced | 81 | &squashfs_lzo_comp_ops, |
7a43ae52 | 82 | &squashfs_xz_comp_ops, |
01a678c5 | 83 | &squashfs_lzma_unsupported_comp_ops, |
87bf54bb | 84 | &squashfs_zstd_comp_ops, |
4c0f0bb2 PL |
85 | &squashfs_unknown_comp_ops |
86 | }; | |
87 | ||
88 | ||
89 | const struct squashfs_decompressor *squashfs_lookup_decompressor(int id) | |
90 | { | |
91 | int i; | |
92 | ||
93 | for (i = 0; decompressor[i]->id; i++) | |
94 | if (id == decompressor[i]->id) | |
95 | break; | |
96 | ||
97 | return decompressor[i]; | |
98 | } | |
b7fc0ff0 PL |
99 | |
100 | ||
9508c6b9 | 101 | static void *get_comp_opts(struct super_block *sb, unsigned short flags) |
b7fc0ff0 PL |
102 | { |
103 | struct squashfs_sb_info *msblk = sb->s_fs_info; | |
9508c6b9 | 104 | void *buffer = NULL, *comp_opts; |
846b730e | 105 | struct squashfs_page_actor *actor = NULL; |
b7fc0ff0 PL |
106 | int length = 0; |
107 | ||
108 | /* | |
109 | * Read decompressor specific options from file system if present | |
110 | */ | |
111 | if (SQUASHFS_COMP_OPTS(flags)) { | |
09cbfeaf | 112 | buffer = kmalloc(PAGE_SIZE, GFP_KERNEL); |
9508c6b9 PL |
113 | if (buffer == NULL) { |
114 | comp_opts = ERR_PTR(-ENOMEM); | |
115 | goto out; | |
116 | } | |
b7fc0ff0 | 117 | |
846b730e PL |
118 | actor = squashfs_page_actor_init(&buffer, 1, 0); |
119 | if (actor == NULL) { | |
120 | comp_opts = ERR_PTR(-ENOMEM); | |
121 | goto out; | |
122 | } | |
123 | ||
124 | length = squashfs_read_data(sb, | |
125 | sizeof(struct squashfs_super_block), 0, NULL, actor); | |
b7fc0ff0 PL |
126 | |
127 | if (length < 0) { | |
9508c6b9 PL |
128 | comp_opts = ERR_PTR(length); |
129 | goto out; | |
b7fc0ff0 PL |
130 | } |
131 | } | |
132 | ||
9508c6b9 | 133 | comp_opts = squashfs_comp_opts(msblk, buffer, length); |
b7fc0ff0 | 134 | |
9508c6b9 | 135 | out: |
846b730e | 136 | kfree(actor); |
b7fc0ff0 | 137 | kfree(buffer); |
9508c6b9 PL |
138 | return comp_opts; |
139 | } | |
140 | ||
141 | ||
142 | void *squashfs_decompressor_setup(struct super_block *sb, unsigned short flags) | |
143 | { | |
144 | struct squashfs_sb_info *msblk = sb->s_fs_info; | |
145 | void *stream, *comp_opts = get_comp_opts(sb, flags); | |
146 | ||
147 | if (IS_ERR(comp_opts)) | |
148 | return comp_opts; | |
149 | ||
150 | stream = squashfs_decompressor_create(msblk, comp_opts); | |
151 | if (IS_ERR(stream)) | |
152 | kfree(comp_opts); | |
b7fc0ff0 | 153 | |
9508c6b9 | 154 | return stream; |
b7fc0ff0 | 155 | } |