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/bio.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
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
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
52 static int zlib_uncompress(struct squashfs_sb_info *msblk, void *strm,
53 struct bio *bio, int offset, int length,
54 struct squashfs_page_actor *output)
55 {
56 struct bvec_iter_all iter_all = {};
57 struct bio_vec *bvec = bvec_init_iter_all(&iter_all);
58 int zlib_init = 0, error = 0;
59 z_stream *stream = strm;
60
61 stream->avail_out = PAGE_SIZE;
62 stream->next_out = squashfs_first_page(output);
63 stream->avail_in = 0;
64
65 if (IS_ERR(stream->next_out)) {
66 error = PTR_ERR(stream->next_out);
67 goto finish;
68 }
69
70 for (;;) {
71 int zlib_err;
72
73 if (stream->avail_in == 0) {
74 const void *data;
75 int avail;
76
77 if (!bio_next_segment(bio, &iter_all)) {
78 /* Z_STREAM_END must be reached. */
79 error = -EIO;
80 break;
81 }
82
83 avail = min(length, ((int)bvec->bv_len) - offset);
84 data = bvec_virt(bvec);
85 length -= avail;
86 stream->next_in = data + offset;
87 stream->avail_in = avail;
88 offset = 0;
89 }
90
91 if (stream->avail_out == 0) {
92 stream->next_out = squashfs_next_page(output);
93 if (IS_ERR(stream->next_out)) {
94 error = PTR_ERR(stream->next_out);
95 break;
96 } else if (stream->next_out != NULL)
97 stream->avail_out = PAGE_SIZE;
98 }
99
100 if (!zlib_init) {
101 zlib_err = zlib_inflateInit(stream);
102 if (zlib_err != Z_OK) {
103 error = -EIO;
104 break;
105 }
106 zlib_init = 1;
107 }
108
109 zlib_err = zlib_inflate(stream, Z_SYNC_FLUSH);
110 if (zlib_err == Z_STREAM_END)
111 break;
112 if (zlib_err != Z_OK) {
113 error = -EIO;
114 break;
115 }
116 }
117
118 finish:
119 squashfs_finish_page(output);
120
121 if (!error)
122 if (zlib_inflateEnd(stream) != Z_OK)
123 error = -EIO;
124
125 return error ? error : stream->total_out;
126 }
127
128 const struct squashfs_decompressor squashfs_zlib_comp_ops = {
129 .init = zlib_init,
130 .free = zlib_free,
131 .decompress = zlib_uncompress,
132 .id = ZLIB_COMPRESSION,
133 .name = "zlib",
134 .alloc_buffer = 1,
135 .supported = 1
136 };
137
138
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.