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Phillip Loughere6a6d372009-09-22 19:25:24 +01001/*
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>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090027#include <linux/slab.h>
Phillip Loughere6a6d372009-09-22 19:25:24 +010028#include <linux/zlib.h>
29
30#include "squashfs_fs.h"
31#include "squashfs_fs_sb.h"
32#include "squashfs_fs_i.h"
33#include "squashfs.h"
Phillip Lougher4c0f0bb2009-10-06 04:04:15 +010034#include "decompressor.h"
Phillip Loughere6a6d372009-09-22 19:25:24 +010035
Phillip Lougher4c0f0bb2009-10-06 04:04:15 +010036static void *zlib_init(struct squashfs_sb_info *dummy)
Phillip Lougherf1a40352009-09-23 19:04:49 +010037{
38 z_stream *stream = kmalloc(sizeof(z_stream), GFP_KERNEL);
39 if (stream == NULL)
40 goto failed;
41 stream->workspace = kmalloc(zlib_inflate_workspacesize(),
42 GFP_KERNEL);
43 if (stream->workspace == NULL)
44 goto failed;
45
46 return stream;
47
48failed:
49 ERROR("Failed to allocate zlib workspace\n");
50 kfree(stream);
51 return NULL;
52}
53
54
Phillip Lougher4c0f0bb2009-10-06 04:04:15 +010055static void zlib_free(void *strm)
Phillip Lougherf1a40352009-09-23 19:04:49 +010056{
57 z_stream *stream = strm;
58
59 if (stream)
60 kfree(stream->workspace);
61 kfree(stream);
62}
63
64
Phillip Lougher4c0f0bb2009-10-06 04:04:15 +010065static int zlib_uncompress(struct squashfs_sb_info *msblk, void **buffer,
Phillip Loughere6a6d372009-09-22 19:25:24 +010066 struct buffer_head **bh, int b, int offset, int length, int srclength,
67 int pages)
68{
69 int zlib_err = 0, zlib_init = 0;
70 int avail, bytes, k = 0, page = 0;
Phillip Lougherf1a40352009-09-23 19:04:49 +010071 z_stream *stream = msblk->stream;
Phillip Loughere6a6d372009-09-22 19:25:24 +010072
73 mutex_lock(&msblk->read_data_mutex);
74
Phillip Lougherf1a40352009-09-23 19:04:49 +010075 stream->avail_out = 0;
76 stream->avail_in = 0;
Phillip Loughere6a6d372009-09-22 19:25:24 +010077
78 bytes = length;
79 do {
Phillip Lougherf1a40352009-09-23 19:04:49 +010080 if (stream->avail_in == 0 && k < b) {
Phillip Loughere6a6d372009-09-22 19:25:24 +010081 avail = min(bytes, msblk->devblksize - offset);
82 bytes -= avail;
83 wait_on_buffer(bh[k]);
84 if (!buffer_uptodate(bh[k]))
85 goto release_mutex;
86
87 if (avail == 0) {
88 offset = 0;
89 put_bh(bh[k++]);
90 continue;
91 }
92
Phillip Lougherf1a40352009-09-23 19:04:49 +010093 stream->next_in = bh[k]->b_data + offset;
94 stream->avail_in = avail;
Phillip Loughere6a6d372009-09-22 19:25:24 +010095 offset = 0;
96 }
97
Phillip Lougherf1a40352009-09-23 19:04:49 +010098 if (stream->avail_out == 0 && page < pages) {
99 stream->next_out = buffer[page++];
100 stream->avail_out = PAGE_CACHE_SIZE;
Phillip Loughere6a6d372009-09-22 19:25:24 +0100101 }
102
103 if (!zlib_init) {
Phillip Lougherf1a40352009-09-23 19:04:49 +0100104 zlib_err = zlib_inflateInit(stream);
Phillip Loughere6a6d372009-09-22 19:25:24 +0100105 if (zlib_err != Z_OK) {
106 ERROR("zlib_inflateInit returned unexpected "
107 "result 0x%x, srclength %d\n",
108 zlib_err, srclength);
109 goto release_mutex;
110 }
111 zlib_init = 1;
112 }
113
Phillip Lougherf1a40352009-09-23 19:04:49 +0100114 zlib_err = zlib_inflate(stream, Z_SYNC_FLUSH);
Phillip Loughere6a6d372009-09-22 19:25:24 +0100115
Phillip Lougherf1a40352009-09-23 19:04:49 +0100116 if (stream->avail_in == 0 && k < b)
Phillip Loughere6a6d372009-09-22 19:25:24 +0100117 put_bh(bh[k++]);
118 } while (zlib_err == Z_OK);
119
120 if (zlib_err != Z_STREAM_END) {
121 ERROR("zlib_inflate error, data probably corrupt\n");
122 goto release_mutex;
123 }
124
Phillip Lougherf1a40352009-09-23 19:04:49 +0100125 zlib_err = zlib_inflateEnd(stream);
Phillip Loughere6a6d372009-09-22 19:25:24 +0100126 if (zlib_err != Z_OK) {
127 ERROR("zlib_inflate error, data probably corrupt\n");
128 goto release_mutex;
129 }
130
Phillip Lougher792590c2010-04-04 22:20:58 +0100131 length = stream->total_out;
Phillip Loughere6a6d372009-09-22 19:25:24 +0100132 mutex_unlock(&msblk->read_data_mutex);
Phillip Lougher792590c2010-04-04 22:20:58 +0100133 return length;
Phillip Loughere6a6d372009-09-22 19:25:24 +0100134
135release_mutex:
136 mutex_unlock(&msblk->read_data_mutex);
137
138 for (; k < b; k++)
139 put_bh(bh[k]);
140
141 return -EIO;
142}
Phillip Lougher4c0f0bb2009-10-06 04:04:15 +0100143
144const struct squashfs_decompressor squashfs_zlib_comp_ops = {
145 .init = zlib_init,
146 .free = zlib_free,
147 .decompress = zlib_uncompress,
148 .id = ZLIB_COMPRESSION,
149 .name = "zlib",
150 .supported = 1
151};
152