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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" | |
33 | ||
34 | /* | |
35 | * This file (and decompressor.h) implements a decompressor framework for | |
36 | * Squashfs, allowing multiple decompressors to be easily supported | |
37 | */ | |
38 | ||
dc325678 PL |
39 | static const struct squashfs_decompressor squashfs_lzma_unsupported_comp_ops = { |
40 | NULL, NULL, NULL, LZMA_COMPRESSION, "lzma", 0 | |
41 | }; | |
42 | ||
79cb8ced | 43 | #ifndef CONFIG_SQUASHFS_LZO |
01a678c5 | 44 | static const struct squashfs_decompressor squashfs_lzo_comp_ops = { |
dc325678 PL |
45 | NULL, NULL, NULL, LZO_COMPRESSION, "lzo", 0 |
46 | }; | |
79cb8ced | 47 | #endif |
dc325678 | 48 | |
7a43ae52 PL |
49 | #ifndef CONFIG_SQUASHFS_XZ |
50 | static const struct squashfs_decompressor squashfs_xz_comp_ops = { | |
51 | NULL, NULL, NULL, XZ_COMPRESSION, "xz", 0 | |
52 | }; | |
53 | #endif | |
54 | ||
4c0f0bb2 PL |
55 | static const struct squashfs_decompressor squashfs_unknown_comp_ops = { |
56 | NULL, NULL, NULL, 0, "unknown", 0 | |
57 | }; | |
58 | ||
59 | static const struct squashfs_decompressor *decompressor[] = { | |
60 | &squashfs_zlib_comp_ops, | |
79cb8ced | 61 | &squashfs_lzo_comp_ops, |
7a43ae52 | 62 | &squashfs_xz_comp_ops, |
01a678c5 | 63 | &squashfs_lzma_unsupported_comp_ops, |
4c0f0bb2 PL |
64 | &squashfs_unknown_comp_ops |
65 | }; | |
66 | ||
67 | ||
68 | const struct squashfs_decompressor *squashfs_lookup_decompressor(int id) | |
69 | { | |
70 | int i; | |
71 | ||
72 | for (i = 0; decompressor[i]->id; i++) | |
73 | if (id == decompressor[i]->id) | |
74 | break; | |
75 | ||
76 | return decompressor[i]; | |
77 | } | |
b7fc0ff0 PL |
78 | |
79 | ||
80 | void *squashfs_decompressor_init(struct super_block *sb, unsigned short flags) | |
81 | { | |
82 | struct squashfs_sb_info *msblk = sb->s_fs_info; | |
83 | void *strm, *buffer = NULL; | |
84 | int length = 0; | |
85 | ||
86 | /* | |
87 | * Read decompressor specific options from file system if present | |
88 | */ | |
89 | if (SQUASHFS_COMP_OPTS(flags)) { | |
90 | buffer = kmalloc(PAGE_CACHE_SIZE, GFP_KERNEL); | |
91 | if (buffer == NULL) | |
92 | return ERR_PTR(-ENOMEM); | |
93 | ||
94 | length = squashfs_read_data(sb, &buffer, | |
95 | sizeof(struct squashfs_super_block), 0, NULL, | |
96 | PAGE_CACHE_SIZE, 1); | |
97 | ||
98 | if (length < 0) { | |
99 | strm = ERR_PTR(length); | |
100 | goto finished; | |
101 | } | |
102 | } | |
103 | ||
104 | strm = msblk->decompressor->init(msblk, buffer, length); | |
105 | ||
106 | finished: | |
107 | kfree(buffer); | |
108 | ||
109 | return strm; | |
110 | } |