Commit | Line | Data |
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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> |
417aca47 AS |
27 | #include <linux/highmem.h> |
28 | #include <linux/fs.h> | |
4c0f0bb2 PL |
29 | |
30 | #include "squashfs_fs.h" | |
31 | #include "squashfs_fs_sb.h" | |
4c0f0bb2 PL |
32 | #include "decompressor.h" |
33 | #include "squashfs.h" | |
846b730e | 34 | #include "page_actor.h" |
4c0f0bb2 PL |
35 | |
36 | /* | |
37 | * This file (and decompressor.h) implements a decompressor framework for | |
38 | * Squashfs, allowing multiple decompressors to be easily supported | |
39 | */ | |
40 | ||
dc325678 | 41 | static const struct squashfs_decompressor squashfs_lzma_unsupported_comp_ops = { |
9508c6b9 | 42 | NULL, NULL, NULL, NULL, LZMA_COMPRESSION, "lzma", 0 |
dc325678 PL |
43 | }; |
44 | ||
62421645 PL |
45 | #ifndef CONFIG_SQUASHFS_LZ4 |
46 | static const struct squashfs_decompressor squashfs_lz4_comp_ops = { | |
47 | NULL, NULL, NULL, NULL, LZ4_COMPRESSION, "lz4", 0 | |
48 | }; | |
49 | #endif | |
50 | ||
79cb8ced | 51 | #ifndef CONFIG_SQUASHFS_LZO |
01a678c5 | 52 | static const struct squashfs_decompressor squashfs_lzo_comp_ops = { |
9508c6b9 | 53 | NULL, NULL, NULL, NULL, LZO_COMPRESSION, "lzo", 0 |
dc325678 | 54 | }; |
79cb8ced | 55 | #endif |
dc325678 | 56 | |
7a43ae52 PL |
57 | #ifndef CONFIG_SQUASHFS_XZ |
58 | static const struct squashfs_decompressor squashfs_xz_comp_ops = { | |
9508c6b9 | 59 | NULL, NULL, NULL, NULL, XZ_COMPRESSION, "xz", 0 |
7a43ae52 PL |
60 | }; |
61 | #endif | |
62 | ||
cc6d3497 PL |
63 | #ifndef CONFIG_SQUASHFS_ZLIB |
64 | static const struct squashfs_decompressor squashfs_zlib_comp_ops = { | |
9508c6b9 | 65 | NULL, NULL, NULL, NULL, ZLIB_COMPRESSION, "zlib", 0 |
cc6d3497 PL |
66 | }; |
67 | #endif | |
68 | ||
4c0f0bb2 | 69 | static const struct squashfs_decompressor squashfs_unknown_comp_ops = { |
9508c6b9 | 70 | NULL, NULL, NULL, NULL, 0, "unknown", 0 |
4c0f0bb2 PL |
71 | }; |
72 | ||
73 | static const struct squashfs_decompressor *decompressor[] = { | |
74 | &squashfs_zlib_comp_ops, | |
62421645 | 75 | &squashfs_lz4_comp_ops, |
79cb8ced | 76 | &squashfs_lzo_comp_ops, |
7a43ae52 | 77 | &squashfs_xz_comp_ops, |
01a678c5 | 78 | &squashfs_lzma_unsupported_comp_ops, |
4c0f0bb2 PL |
79 | &squashfs_unknown_comp_ops |
80 | }; | |
81 | ||
82 | ||
83 | const struct squashfs_decompressor *squashfs_lookup_decompressor(int id) | |
84 | { | |
85 | int i; | |
86 | ||
87 | for (i = 0; decompressor[i]->id; i++) | |
88 | if (id == decompressor[i]->id) | |
89 | break; | |
90 | ||
91 | return decompressor[i]; | |
92 | } | |
b7fc0ff0 PL |
93 | |
94 | ||
9508c6b9 | 95 | static void *get_comp_opts(struct super_block *sb, unsigned short flags) |
b7fc0ff0 PL |
96 | { |
97 | struct squashfs_sb_info *msblk = sb->s_fs_info; | |
417aca47 AS |
98 | void *comp_opts, *buffer = NULL; |
99 | struct page *page; | |
846b730e | 100 | struct squashfs_page_actor *actor = NULL; |
b7fc0ff0 PL |
101 | int length = 0; |
102 | ||
417aca47 AS |
103 | if (!SQUASHFS_COMP_OPTS(flags)) |
104 | return squashfs_comp_opts(msblk, buffer, length); | |
105 | ||
b7fc0ff0 PL |
106 | /* |
107 | * Read decompressor specific options from file system if present | |
108 | */ | |
417aca47 AS |
109 | |
110 | page = alloc_page(GFP_KERNEL); | |
111 | if (!page) | |
112 | return ERR_PTR(-ENOMEM); | |
113 | ||
114 | actor = squashfs_page_actor_init(&page, 1, 0, NULL); | |
115 | if (actor == NULL) { | |
116 | comp_opts = ERR_PTR(-ENOMEM); | |
117 | goto actor_error; | |
118 | } | |
119 | ||
120 | length = squashfs_read_data(sb, | |
121 | sizeof(struct squashfs_super_block), 0, NULL, actor); | |
122 | ||
123 | if (length < 0) { | |
124 | comp_opts = ERR_PTR(length); | |
125 | goto read_error; | |
b7fc0ff0 PL |
126 | } |
127 | ||
417aca47 | 128 | buffer = kmap_atomic(page); |
9508c6b9 | 129 | comp_opts = squashfs_comp_opts(msblk, buffer, length); |
417aca47 | 130 | kunmap_atomic(buffer); |
b7fc0ff0 | 131 | |
417aca47 AS |
132 | read_error: |
133 | squashfs_page_actor_free(actor, 0); | |
134 | actor_error: | |
135 | __free_page(page); | |
9508c6b9 PL |
136 | return comp_opts; |
137 | } | |
138 | ||
139 | ||
140 | void *squashfs_decompressor_setup(struct super_block *sb, unsigned short flags) | |
141 | { | |
142 | struct squashfs_sb_info *msblk = sb->s_fs_info; | |
143 | void *stream, *comp_opts = get_comp_opts(sb, flags); | |
144 | ||
145 | if (IS_ERR(comp_opts)) | |
146 | return comp_opts; | |
147 | ||
148 | stream = squashfs_decompressor_create(msblk, comp_opts); | |
149 | if (IS_ERR(stream)) | |
150 | kfree(comp_opts); | |
b7fc0ff0 | 151 | |
9508c6b9 | 152 | return stream; |
b7fc0ff0 | 153 | } |