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(error: -ENOMEM); |
101 | goto out; |
102 | } |
103 | |
104 | actor = squashfs_page_actor_init(buffer: &buffer, pages: 1, length: 0); |
105 | if (actor == NULL) { |
106 | comp_opts = ERR_PTR(error: -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(error: length); |
115 | goto out; |
116 | } |
117 | } |
118 | |
119 | comp_opts = squashfs_comp_opts(msblk, buff: buffer, length); |
120 | |
121 | out: |
122 | kfree(objp: actor); |
123 | kfree(objp: 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(ptr: comp_opts)) |
134 | return comp_opts; |
135 | |
136 | stream = msblk->thread_ops->create(msblk, comp_opts); |
137 | if (IS_ERR(ptr: stream)) |
138 | kfree(objp: comp_opts); |
139 | |
140 | return stream; |
141 | } |
142 | |