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e6a6d379 PL |
1 | /* |
2 | * Squashfs - a compressed read only filesystem for Linux | |
3 | * | |
4 | * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 | |
5 | * Phillip Lougher <phillip@lougher.demon.co.uk> | |
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 | * zlib_wrapper.c | |
22 | */ | |
23 | ||
24 | ||
25 | #include <linux/mutex.h> | |
26 | #include <linux/buffer_head.h> | |
27 | #include <linux/zlib.h> | |
28 | ||
29 | #include "squashfs_fs.h" | |
30 | #include "squashfs_fs_sb.h" | |
31 | #include "squashfs_fs_i.h" | |
32 | #include "squashfs.h" | |
4c0f0bb2 | 33 | #include "decompressor.h" |
e6a6d379 | 34 | |
4c0f0bb2 | 35 | static void *zlib_init(struct squashfs_sb_info *dummy) |
f1a40359 PL |
36 | { |
37 | z_stream *stream = kmalloc(sizeof(z_stream), GFP_KERNEL); | |
38 | if (stream == NULL) | |
39 | goto failed; | |
40 | stream->workspace = kmalloc(zlib_inflate_workspacesize(), | |
41 | GFP_KERNEL); | |
42 | if (stream->workspace == NULL) | |
43 | goto failed; | |
44 | ||
45 | return stream; | |
46 | ||
47 | failed: | |
48 | ERROR("Failed to allocate zlib workspace\n"); | |
49 | kfree(stream); | |
50 | return NULL; | |
51 | } | |
52 | ||
53 | ||
4c0f0bb2 | 54 | static void zlib_free(void *strm) |
f1a40359 PL |
55 | { |
56 | z_stream *stream = strm; | |
57 | ||
58 | if (stream) | |
59 | kfree(stream->workspace); | |
60 | kfree(stream); | |
61 | } | |
62 | ||
63 | ||
4c0f0bb2 | 64 | static int zlib_uncompress(struct squashfs_sb_info *msblk, void **buffer, |
e6a6d379 PL |
65 | struct buffer_head **bh, int b, int offset, int length, int srclength, |
66 | int pages) | |
67 | { | |
68 | int zlib_err = 0, zlib_init = 0; | |
69 | int avail, bytes, k = 0, page = 0; | |
f1a40359 | 70 | z_stream *stream = msblk->stream; |
e6a6d379 PL |
71 | |
72 | mutex_lock(&msblk->read_data_mutex); | |
73 | ||
f1a40359 PL |
74 | stream->avail_out = 0; |
75 | stream->avail_in = 0; | |
e6a6d379 PL |
76 | |
77 | bytes = length; | |
78 | do { | |
f1a40359 | 79 | if (stream->avail_in == 0 && k < b) { |
e6a6d379 PL |
80 | avail = min(bytes, msblk->devblksize - offset); |
81 | bytes -= avail; | |
82 | wait_on_buffer(bh[k]); | |
83 | if (!buffer_uptodate(bh[k])) | |
84 | goto release_mutex; | |
85 | ||
86 | if (avail == 0) { | |
87 | offset = 0; | |
88 | put_bh(bh[k++]); | |
89 | continue; | |
90 | } | |
91 | ||
f1a40359 PL |
92 | stream->next_in = bh[k]->b_data + offset; |
93 | stream->avail_in = avail; | |
e6a6d379 PL |
94 | offset = 0; |
95 | } | |
96 | ||
f1a40359 PL |
97 | if (stream->avail_out == 0 && page < pages) { |
98 | stream->next_out = buffer[page++]; | |
99 | stream->avail_out = PAGE_CACHE_SIZE; | |
e6a6d379 PL |
100 | } |
101 | ||
102 | if (!zlib_init) { | |
f1a40359 | 103 | zlib_err = zlib_inflateInit(stream); |
e6a6d379 PL |
104 | if (zlib_err != Z_OK) { |
105 | ERROR("zlib_inflateInit returned unexpected " | |
106 | "result 0x%x, srclength %d\n", | |
107 | zlib_err, srclength); | |
108 | goto release_mutex; | |
109 | } | |
110 | zlib_init = 1; | |
111 | } | |
112 | ||
f1a40359 | 113 | zlib_err = zlib_inflate(stream, Z_SYNC_FLUSH); |
e6a6d379 | 114 | |
f1a40359 | 115 | if (stream->avail_in == 0 && k < b) |
e6a6d379 PL |
116 | put_bh(bh[k++]); |
117 | } while (zlib_err == Z_OK); | |
118 | ||
119 | if (zlib_err != Z_STREAM_END) { | |
120 | ERROR("zlib_inflate error, data probably corrupt\n"); | |
121 | goto release_mutex; | |
122 | } | |
123 | ||
f1a40359 | 124 | zlib_err = zlib_inflateEnd(stream); |
e6a6d379 PL |
125 | if (zlib_err != Z_OK) { |
126 | ERROR("zlib_inflate error, data probably corrupt\n"); | |
127 | goto release_mutex; | |
128 | } | |
129 | ||
130 | mutex_unlock(&msblk->read_data_mutex); | |
f1a40359 | 131 | return stream->total_out; |
e6a6d379 PL |
132 | |
133 | release_mutex: | |
134 | mutex_unlock(&msblk->read_data_mutex); | |
135 | ||
136 | for (; k < b; k++) | |
137 | put_bh(bh[k]); | |
138 | ||
139 | return -EIO; | |
140 | } | |
4c0f0bb2 PL |
141 | |
142 | const struct squashfs_decompressor squashfs_zlib_comp_ops = { | |
143 | .init = zlib_init, | |
144 | .free = zlib_free, | |
145 | .decompress = zlib_uncompress, | |
146 | .id = ZLIB_COMPRESSION, | |
147 | .name = "zlib", | |
148 | .supported = 1 | |
149 | }; | |
150 |