aboutsummaryrefslogtreecommitdiff
path: root/fs/squashfs/xz_wrapper.c
blob: c4eb400182564c13728fc88f95edf6db294eb2ac (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
/*
 * Squashfs - a compressed read only filesystem for Linux
 *
 * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
 * Phillip Lougher <phillip@lougher.demon.co.uk>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2,
 * or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * xz_wrapper.c
 */


#include <linux/mutex.h>
#include <linux/buffer_head.h>
#include <linux/slab.h>
#include <linux/xz.h>

#include "squashfs_fs.h"
#include "squashfs_fs_sb.h"
#include "squashfs_fs_i.h"
#include "squashfs.h"
#include "decompressor.h"

struct squashfs_xz {
	struct xz_dec *state;
	struct xz_buf buf;
};

static void *squashfs_xz_init(struct squashfs_sb_info *msblk)
{
	int block_size = max_t(int, msblk->block_size, SQUASHFS_METADATA_SIZE);

	struct squashfs_xz *stream = kmalloc(sizeof(*stream), GFP_KERNEL);
	if (stream == NULL)
		goto failed;

	stream->state = xz_dec_init(XZ_PREALLOC, block_size);
	if (stream->state == NULL)
		goto failed;

	return stream;

failed:
	ERROR("Failed to allocate xz workspace\n");
	kfree(stream);
	return NULL;
}


static void squashfs_xz_free(void *strm)
{
	struct squashfs_xz *stream = strm;

	if (stream) {
		xz_dec_end(stream->state);
		kfree(stream);
	}
}


static int squashfs_xz_uncompress(struct squashfs_sb_info *msblk, void **buffer,
	struct buffer_head **bh, int b, int offset, int length, int srclength,
	int pages)
{
	enum xz_ret xz_err;
	int avail, total = 0, k = 0, page = 0;
	struct squashfs_xz *stream = msblk->stream;

	mutex_lock(&msblk->read_data_mutex);

	xz_dec_reset(stream->state);
	stream->buf.in_pos = 0;
	stream->buf.in_size = 0;
	stream->buf.out_pos = 0;
	stream->buf.out_size = PAGE_CACHE_SIZE;
	stream->buf.out = buffer[page++];

	do {
		if (stream->buf.in_pos == stream->buf.in_size && k < b) {
			avail = min(length, msblk->devblksize - offset);
			length -= avail;
			wait_on_buffer(bh[k]);
			if (!buffer_uptodate(bh[k]))
				goto release_mutex;

			stream->buf.in = bh[k]->b_data + offset;
			stream->buf.in_size = avail;
			stream->buf.in_pos = 0;
			offset = 0;
		}

		if (stream->buf.out_pos == stream->buf.out_size
							&& page < pages) {
			stream->buf.out = buffer[page++];
			stream->buf.out_pos = 0;
			total += PAGE_CACHE_SIZE;
		}

		xz_err = xz_dec_run(stream->state, &stream->buf);

		if (stream->buf.in_pos == stream->buf.in_size && k < b)
			put_bh(bh[k++]);
	} while (xz_err == XZ_OK);

	if (xz_err != XZ_STREAM_END) {
		ERROR("xz_dec_run error, data probably corrupt\n");
		goto release_mutex;
	}

	if (k < b) {
		ERROR("xz_uncompress error, input remaining\n");
		goto release_mutex;
	}

	total += stream->buf.out_pos;
	mutex_unlock(&msblk->read_data_mutex);
	return total;

release_mutex:
	mutex_unlock(&msblk->read_data_mutex);

	for (; k < b; k++)
		put_bh(bh[k]);

	return -EIO;
}

const struct squashfs_decompressor squashfs_xz_comp_ops = {
	.init = squashfs_xz_init,
	.free = squashfs_xz_free,
	.decompress = squashfs_xz_uncompress,
	.id = XZ_COMPRESSION,
	.name = "xz",
	.supported = 1
};