Commit | Line | Data |
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9c06a46f PL |
1 | /* |
2 | * Copyright (c) 2013, 2014 | |
3 | * Phillip Lougher <phillip@squashfs.org.uk> | |
4 | * | |
5 | * This work is licensed under the terms of the GNU GPL, version 2. See | |
6 | * the COPYING file in the top-level directory. | |
7 | */ | |
8 | ||
9 | #include <linux/buffer_head.h> | |
10 | #include <linux/mutex.h> | |
11 | #include <linux/slab.h> | |
12 | #include <linux/vmalloc.h> | |
13 | #include <linux/lz4.h> | |
14 | ||
15 | #include "squashfs_fs.h" | |
16 | #include "squashfs_fs_sb.h" | |
17 | #include "squashfs.h" | |
18 | #include "decompressor.h" | |
19 | #include "page_actor.h" | |
20 | ||
21 | #define LZ4_LEGACY 1 | |
22 | ||
23 | struct lz4_comp_opts { | |
24 | __le32 version; | |
25 | __le32 flags; | |
26 | }; | |
27 | ||
28 | struct squashfs_lz4 { | |
29 | void *input; | |
30 | void *output; | |
31 | }; | |
32 | ||
33 | ||
34 | static void *lz4_comp_opts(struct squashfs_sb_info *msblk, | |
35 | void *buff, int len) | |
36 | { | |
37 | struct lz4_comp_opts *comp_opts = buff; | |
38 | ||
39 | /* LZ4 compressed filesystems always have compression options */ | |
40 | if (comp_opts == NULL || len < sizeof(*comp_opts)) | |
41 | return ERR_PTR(-EIO); | |
42 | ||
43 | if (le32_to_cpu(comp_opts->version) != LZ4_LEGACY) { | |
44 | /* LZ4 format currently used by the kernel is the 'legacy' | |
45 | * format */ | |
46 | ERROR("Unknown LZ4 version\n"); | |
47 | return ERR_PTR(-EINVAL); | |
48 | } | |
49 | ||
50 | return NULL; | |
51 | } | |
52 | ||
53 | ||
54 | static void *lz4_init(struct squashfs_sb_info *msblk, void *buff) | |
55 | { | |
56 | int block_size = max_t(int, msblk->block_size, SQUASHFS_METADATA_SIZE); | |
57 | struct squashfs_lz4 *stream; | |
58 | ||
59 | stream = kzalloc(sizeof(*stream), GFP_KERNEL); | |
60 | if (stream == NULL) | |
61 | goto failed; | |
62 | stream->input = vmalloc(block_size); | |
63 | if (stream->input == NULL) | |
64 | goto failed2; | |
65 | stream->output = vmalloc(block_size); | |
66 | if (stream->output == NULL) | |
67 | goto failed3; | |
68 | ||
69 | return stream; | |
70 | ||
71 | failed3: | |
72 | vfree(stream->input); | |
73 | failed2: | |
74 | kfree(stream); | |
75 | failed: | |
76 | ERROR("Failed to initialise LZ4 decompressor\n"); | |
77 | return ERR_PTR(-ENOMEM); | |
78 | } | |
79 | ||
80 | ||
81 | static void lz4_free(void *strm) | |
82 | { | |
83 | struct squashfs_lz4 *stream = strm; | |
84 | ||
85 | if (stream) { | |
86 | vfree(stream->input); | |
87 | vfree(stream->output); | |
88 | } | |
89 | kfree(stream); | |
90 | } | |
91 | ||
92 | ||
93 | static int lz4_uncompress(struct squashfs_sb_info *msblk, void *strm, | |
94 | struct buffer_head **bh, int b, int offset, int length, | |
95 | struct squashfs_page_actor *output) | |
96 | { | |
97 | struct squashfs_lz4 *stream = strm; | |
98 | void *buff = stream->input, *data; | |
99 | int avail, i, bytes = length, res; | |
100 | size_t dest_len = output->length; | |
101 | ||
102 | for (i = 0; i < b; i++) { | |
103 | avail = min(bytes, msblk->devblksize - offset); | |
104 | memcpy(buff, bh[i]->b_data + offset, avail); | |
105 | buff += avail; | |
106 | bytes -= avail; | |
107 | offset = 0; | |
108 | put_bh(bh[i]); | |
109 | } | |
110 | ||
111 | res = lz4_decompress_unknownoutputsize(stream->input, length, | |
112 | stream->output, &dest_len); | |
113 | if (res) | |
114 | return -EIO; | |
115 | ||
116 | bytes = dest_len; | |
117 | data = squashfs_first_page(output); | |
118 | buff = stream->output; | |
119 | while (data) { | |
120 | if (bytes <= PAGE_CACHE_SIZE) { | |
121 | memcpy(data, buff, bytes); | |
122 | break; | |
123 | } | |
124 | memcpy(data, buff, PAGE_CACHE_SIZE); | |
125 | buff += PAGE_CACHE_SIZE; | |
126 | bytes -= PAGE_CACHE_SIZE; | |
127 | data = squashfs_next_page(output); | |
128 | } | |
129 | squashfs_finish_page(output); | |
130 | ||
131 | return dest_len; | |
132 | } | |
133 | ||
134 | const struct squashfs_decompressor squashfs_lz4_comp_ops = { | |
135 | .init = lz4_init, | |
136 | .comp_opts = lz4_comp_opts, | |
137 | .free = lz4_free, | |
138 | .decompress = lz4_uncompress, | |
139 | .id = LZ4_COMPRESSION, | |
140 | .name = "lz4", | |
141 | .supported = 1 | |
142 | }; |