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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 | ||
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 | ||
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 | ||
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 | int zlib_err, zlib_init = 0, k = 0; | |
70 | z_stream *stream = strm; | |
71 | ||
72 | stream->avail_out = PAGE_CACHE_SIZE; | |
73 | stream->next_out = squashfs_first_page(output); | |
74 | stream->avail_in = 0; | |
75 | ||
76 | do { | |
77 | if (stream->avail_in == 0 && k < b) { | |
78 | int avail = min(length, msblk->devblksize - offset); | |
79 | length -= avail; | |
80 | stream->next_in = bh[k]->b_data + offset; | |
81 | stream->avail_in = avail; | |
82 | offset = 0; | |
83 | } | |
84 | ||
85 | if (stream->avail_out == 0) { | |
86 | stream->next_out = squashfs_next_page(output); | |
87 | if (stream->next_out != NULL) | |
88 | stream->avail_out = PAGE_CACHE_SIZE; | |
89 | } | |
90 | ||
91 | if (!zlib_init) { | |
92 | zlib_err = zlib_inflateInit(stream); | |
93 | if (zlib_err != Z_OK) { | |
94 | squashfs_finish_page(output); | |
95 | goto out; | |
96 | } | |
97 | zlib_init = 1; | |
98 | } | |
99 | ||
100 | zlib_err = zlib_inflate(stream, Z_SYNC_FLUSH); | |
101 | ||
102 | if (stream->avail_in == 0 && k < b) | |
103 | put_bh(bh[k++]); | |
104 | } while (zlib_err == Z_OK); | |
105 | ||
106 | squashfs_finish_page(output); | |
107 | ||
108 | if (zlib_err != Z_STREAM_END) | |
109 | goto out; | |
110 | ||
111 | zlib_err = zlib_inflateEnd(stream); | |
112 | if (zlib_err != Z_OK) | |
113 | goto out; | |
114 | ||
115 | if (k < b) | |
116 | goto out; | |
117 | ||
118 | return stream->total_out; | |
119 | ||
120 | out: | |
121 | for (; k < b; k++) | |
122 | put_bh(bh[k]); | |
123 | ||
124 | return -EIO; | |
125 | } | |
126 | ||
127 | const struct squashfs_decompressor squashfs_zlib_comp_ops = { | |
128 | .init = zlib_init, | |
129 | .free = zlib_free, | |
130 | .decompress = zlib_uncompress, | |
131 | .id = ZLIB_COMPRESSION, | |
132 | .name = "zlib", | |
133 | .supported = 1 | |
134 | }; | |
135 |