1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Squashfs - a compressed read only filesystem for Linux
4 *
5 * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
6 * Phillip Lougher <phillip@squashfs.org.uk>
7 *
8 * zlib_wrapper.c
9 */
10
11
12 #include <linux/mutex.h>
13 #include <linux/buffer_head.h>
14 #include <linux/slab.h>
15 #include <linux/zlib.h>
16 #include <linux/vmalloc.h>
17
18 #include "squashfs_fs.h"
19 #include "squashfs_fs_sb.h"
20 #include "squashfs.h"
21 #include "decompressor.h"
22 #include "page_actor.h"
23
zlib_init(struct squashfs_sb_info * dummy,void * buff)24 static void *zlib_init(struct squashfs_sb_info *dummy, void *buff)
25 {
26 z_stream *stream = kmalloc(sizeof(z_stream), GFP_KERNEL);
27 if (stream == NULL)
28 goto failed;
29 stream->workspace = vmalloc(zlib_inflate_workspacesize());
30 if (stream->workspace == NULL)
31 goto failed;
32
33 return stream;
34
35 failed:
36 ERROR("Failed to allocate zlib workspace\n");
37 kfree(stream);
38 return ERR_PTR(-ENOMEM);
39 }
40
41
zlib_free(void * strm)42 static void zlib_free(void *strm)
43 {
44 z_stream *stream = strm;
45
46 if (stream)
47 vfree(stream->workspace);
48 kfree(stream);
49 }
50
51
zlib_uncompress(struct squashfs_sb_info * msblk,void * strm,struct buffer_head ** bh,int b,int offset,int length,struct squashfs_page_actor * output)52 static int zlib_uncompress(struct squashfs_sb_info *msblk, void *strm,
53 struct buffer_head **bh, int b, int offset, int length,
54 struct squashfs_page_actor *output)
55 {
56 int zlib_err, zlib_init = 0, k = 0;
57 z_stream *stream = strm;
58
59 stream->avail_out = PAGE_SIZE;
60 stream->next_out = squashfs_first_page(output);
61 stream->avail_in = 0;
62
63 do {
64 if (stream->avail_in == 0 && k < b) {
65 int avail = min(length, msblk->devblksize - offset);
66 length -= avail;
67 stream->next_in = bh[k]->b_data + offset;
68 stream->avail_in = avail;
69 offset = 0;
70 }
71
72 if (stream->avail_out == 0) {
73 stream->next_out = squashfs_next_page(output);
74 if (stream->next_out != NULL)
75 stream->avail_out = PAGE_SIZE;
76 }
77
78 if (!zlib_init) {
79 zlib_err = zlib_inflateInit(stream);
80 if (zlib_err != Z_OK) {
81 squashfs_finish_page(output);
82 goto out;
83 }
84 zlib_init = 1;
85 }
86
87 zlib_err = zlib_inflate(stream, Z_SYNC_FLUSH);
88
89 if (stream->avail_in == 0 && k < b)
90 put_bh(bh[k++]);
91 } while (zlib_err == Z_OK);
92
93 squashfs_finish_page(output);
94
95 if (zlib_err != Z_STREAM_END)
96 goto out;
97
98 zlib_err = zlib_inflateEnd(stream);
99 if (zlib_err != Z_OK)
100 goto out;
101
102 if (k < b)
103 goto out;
104
105 return stream->total_out;
106
107 out:
108 for (; k < b; k++)
109 put_bh(bh[k]);
110
111 return -EIO;
112 }
113
114 const struct squashfs_decompressor squashfs_zlib_comp_ops = {
115 .init = zlib_init,
116 .free = zlib_free,
117 .decompress = zlib_uncompress,
118 .id = ZLIB_COMPRESSION,
119 .name = "zlib",
120 .supported = 1
121 };
122
123