Commit | Line | Data |
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81bb8deb PL |
1 | /* |
2 | * Squashfs - a compressed read only filesystem for Linux | |
3 | * | |
4 | * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 | |
d7f2ff67 | 5 | * Phillip Lougher <phillip@squashfs.org.uk> |
81bb8deb 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 | * xz_wrapper.c | |
22 | */ | |
23 | ||
24 | ||
25 | #include <linux/mutex.h> | |
26 | #include <linux/buffer_head.h> | |
27 | #include <linux/slab.h> | |
28 | #include <linux/xz.h> | |
ff750311 | 29 | #include <linux/bitops.h> |
81bb8deb PL |
30 | |
31 | #include "squashfs_fs.h" | |
32 | #include "squashfs_fs_sb.h" | |
81bb8deb PL |
33 | #include "squashfs.h" |
34 | #include "decompressor.h" | |
35 | ||
36 | struct squashfs_xz { | |
37 | struct xz_dec *state; | |
38 | struct xz_buf buf; | |
39 | }; | |
40 | ||
ff750311 PL |
41 | struct comp_opts { |
42 | __le32 dictionary_size; | |
43 | __le32 flags; | |
44 | }; | |
45 | ||
b7fc0ff0 PL |
46 | static void *squashfs_xz_init(struct squashfs_sb_info *msblk, void *buff, |
47 | int len) | |
81bb8deb | 48 | { |
ff750311 PL |
49 | struct comp_opts *comp_opts = buff; |
50 | struct squashfs_xz *stream; | |
51 | int dict_size = msblk->block_size; | |
52 | int err, n; | |
53 | ||
54 | if (comp_opts) { | |
55 | /* check compressor options are the expected length */ | |
56 | if (len < sizeof(*comp_opts)) { | |
57 | err = -EIO; | |
58 | goto failed; | |
59 | } | |
60 | ||
61 | dict_size = le32_to_cpu(comp_opts->dictionary_size); | |
62 | ||
63 | /* the dictionary size should be 2^n or 2^n+2^(n+1) */ | |
64 | n = ffs(dict_size) - 1; | |
65 | if (dict_size != (1 << n) && dict_size != (1 << n) + | |
66 | (1 << (n + 1))) { | |
67 | err = -EIO; | |
68 | goto failed; | |
69 | } | |
70 | } | |
71 | ||
72 | dict_size = max_t(int, dict_size, SQUASHFS_METADATA_SIZE); | |
81bb8deb | 73 | |
ff750311 PL |
74 | stream = kmalloc(sizeof(*stream), GFP_KERNEL); |
75 | if (stream == NULL) { | |
76 | err = -ENOMEM; | |
81bb8deb | 77 | goto failed; |
ff750311 | 78 | } |
81bb8deb | 79 | |
ff750311 PL |
80 | stream->state = xz_dec_init(XZ_PREALLOC, dict_size); |
81 | if (stream->state == NULL) { | |
82 | kfree(stream); | |
83 | err = -ENOMEM; | |
81bb8deb | 84 | goto failed; |
ff750311 | 85 | } |
81bb8deb PL |
86 | |
87 | return stream; | |
88 | ||
89 | failed: | |
ff750311 PL |
90 | ERROR("Failed to initialise xz decompressor\n"); |
91 | return ERR_PTR(err); | |
81bb8deb PL |
92 | } |
93 | ||
94 | ||
95 | static void squashfs_xz_free(void *strm) | |
96 | { | |
97 | struct squashfs_xz *stream = strm; | |
98 | ||
99 | if (stream) { | |
100 | xz_dec_end(stream->state); | |
101 | kfree(stream); | |
102 | } | |
103 | } | |
104 | ||
105 | ||
106 | static int squashfs_xz_uncompress(struct squashfs_sb_info *msblk, void **buffer, | |
107 | struct buffer_head **bh, int b, int offset, int length, int srclength, | |
108 | int pages) | |
109 | { | |
110 | enum xz_ret xz_err; | |
111 | int avail, total = 0, k = 0, page = 0; | |
112 | struct squashfs_xz *stream = msblk->stream; | |
113 | ||
114 | mutex_lock(&msblk->read_data_mutex); | |
115 | ||
116 | xz_dec_reset(stream->state); | |
117 | stream->buf.in_pos = 0; | |
118 | stream->buf.in_size = 0; | |
119 | stream->buf.out_pos = 0; | |
120 | stream->buf.out_size = PAGE_CACHE_SIZE; | |
121 | stream->buf.out = buffer[page++]; | |
122 | ||
123 | do { | |
124 | if (stream->buf.in_pos == stream->buf.in_size && k < b) { | |
125 | avail = min(length, msblk->devblksize - offset); | |
126 | length -= avail; | |
127 | wait_on_buffer(bh[k]); | |
128 | if (!buffer_uptodate(bh[k])) | |
129 | goto release_mutex; | |
130 | ||
81bb8deb PL |
131 | stream->buf.in = bh[k]->b_data + offset; |
132 | stream->buf.in_size = avail; | |
133 | stream->buf.in_pos = 0; | |
134 | offset = 0; | |
135 | } | |
136 | ||
137 | if (stream->buf.out_pos == stream->buf.out_size | |
138 | && page < pages) { | |
139 | stream->buf.out = buffer[page++]; | |
140 | stream->buf.out_pos = 0; | |
141 | total += PAGE_CACHE_SIZE; | |
142 | } | |
143 | ||
144 | xz_err = xz_dec_run(stream->state, &stream->buf); | |
145 | ||
146 | if (stream->buf.in_pos == stream->buf.in_size && k < b) | |
147 | put_bh(bh[k++]); | |
148 | } while (xz_err == XZ_OK); | |
149 | ||
150 | if (xz_err != XZ_STREAM_END) { | |
151 | ERROR("xz_dec_run error, data probably corrupt\n"); | |
152 | goto release_mutex; | |
153 | } | |
154 | ||
155 | if (k < b) { | |
156 | ERROR("xz_uncompress error, input remaining\n"); | |
157 | goto release_mutex; | |
158 | } | |
159 | ||
160 | total += stream->buf.out_pos; | |
161 | mutex_unlock(&msblk->read_data_mutex); | |
162 | return total; | |
163 | ||
164 | release_mutex: | |
165 | mutex_unlock(&msblk->read_data_mutex); | |
166 | ||
167 | for (; k < b; k++) | |
168 | put_bh(bh[k]); | |
169 | ||
170 | return -EIO; | |
171 | } | |
172 | ||
173 | const struct squashfs_decompressor squashfs_xz_comp_ops = { | |
174 | .init = squashfs_xz_init, | |
175 | .free = squashfs_xz_free, | |
176 | .decompress = squashfs_xz_uncompress, | |
177 | .id = XZ_COMPRESSION, | |
178 | .name = "xz", | |
179 | .supported = 1 | |
180 | }; |