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
24static 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
35failed:
36	ERROR("Failed to allocate zlib workspace\n");
37	kfree(stream);
38	return ERR_PTR(-ENOMEM);
39}
40
41
42static 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
52static 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
118finish:
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
128const 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