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@squashfs.org.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/slab.h>
28 #include <linux/zlib.h>
29 #include <linux/vmalloc.h>
30
31 #include "squashfs_fs.h"
32 #include "squashfs_fs_sb.h"
33 #include "squashfs.h"
34 #include "decompressor.h"
35 #include "page_actor.h"
36
zlib_init(struct squashfs_sb_info * dummy,void * buff)37 static void *zlib_init(struct squashfs_sb_info *dummy, void *buff)
38 {
39 z_stream *stream = kmalloc(sizeof(z_stream), GFP_KERNEL);
40 if (stream == NULL)
41 goto failed;
42 stream->workspace = vmalloc(zlib_inflate_workspacesize());
43 if (stream->workspace == NULL)
44 goto failed;
45
46 return stream;
47
48 failed:
49 ERROR("Failed to allocate zlib workspace\n");
50 kfree(stream);
51 return ERR_PTR(-ENOMEM);
52 }
53
54
zlib_free(void * strm)55 static void zlib_free(void *strm)
56 {
57 z_stream *stream = strm;
58
59 if (stream)
60 vfree(stream->workspace);
61 kfree(stream);
62 }
63
64
zlib_uncompress(struct squashfs_sb_info * msblk,void * strm,struct buffer_head ** bh,int b,int offset,int length,struct squashfs_page_actor * output)65 static int zlib_uncompress(struct squashfs_sb_info *msblk, void *strm,
66 struct buffer_head **bh, int b, int offset, int length,
67 struct squashfs_page_actor *output)
68 {
69 void *buf = NULL;
70 int zlib_err, zlib_init = 0, k = 0;
71 z_stream *stream = strm;
72
73 stream->avail_out = PAGE_SIZE;
74 stream->next_out = squashfs_first_page(output);
75 stream->avail_in = 0;
76
77 do {
78 if (stream->avail_in == 0 && k < b) {
79 int avail = min(length, msblk->devblksize - offset);
80 length -= avail;
81 stream->next_in = bh[k]->b_data + offset;
82 stream->avail_in = avail;
83 offset = 0;
84 }
85
86 if (stream->avail_out == 0) {
87 stream->next_out = squashfs_next_page(output);
88 if (!IS_ERR(stream->next_out))
89 stream->avail_out = PAGE_SIZE;
90 }
91
92 if (!stream->next_out) {
93 if (!buf) {
94 buf = kmalloc(PAGE_SIZE, GFP_ATOMIC);
95 if (!buf)
96 goto out;
97 }
98 stream->next_out = buf;
99 }
100
101 if (!zlib_init) {
102 zlib_err = zlib_inflateInit(stream);
103 if (zlib_err != Z_OK) {
104 squashfs_finish_page(output);
105 goto out;
106 }
107 zlib_init = 1;
108 }
109
110 zlib_err = zlib_inflate(stream, Z_SYNC_FLUSH);
111
112 if (stream->avail_in == 0 && k < b)
113 put_bh(bh[k++]);
114 } while (zlib_err == Z_OK);
115
116 squashfs_finish_page(output);
117
118 if (zlib_err != Z_STREAM_END)
119 goto out;
120
121 zlib_err = zlib_inflateEnd(stream);
122 if (zlib_err != Z_OK)
123 goto out;
124
125 if (k < b)
126 goto out;
127
128 kfree(buf);
129 return stream->total_out;
130
131 out:
132 for (; k < b; k++)
133 put_bh(bh[k]);
134 kfree(buf);
135
136 return -EIO;
137 }
138
139 const struct squashfs_decompressor squashfs_zlib_comp_ops = {
140 .init = zlib_init,
141 .free = zlib_free,
142 .decompress = zlib_uncompress,
143 .id = ZLIB_COMPRESSION,
144 .name = "zlib",
145 .supported = 1
146 };
147
148