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
37static 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
48failed:
49	ERROR("Failed to allocate zlib workspace\n");
50	kfree(stream);
51	return ERR_PTR(-ENOMEM);
52}
53
54
55static 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
65static 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
120out:
121	for (; k < b; k++)
122		put_bh(bh[k]);
123
124	return -EIO;
125}
126
127const 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
136