source: src/linux/universal/linux-4.9/fs/squashfs/zlib_wrapper.c @ 31630

Last change on this file since 31630 was 31630, checked in by brainslayer, 12 days ago

new fs is compatible with standard squashfs, just smaller

File size: 3.1 KB
Line 
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_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_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
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