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	for (;;) {
66		int zlib_err;
67
68		if (stream->avail_in == 0) {
69			const void *data;
70			int avail;
71
72			if (!bio_next_segment(bio, &iter_all)) {
73				/* Z_STREAM_END must be reached. */
74				error = -EIO;
75				break;
76			}
77
78			avail = min(length, ((int)bvec->bv_len) - offset);
79			data = page_address(bvec->bv_page) + bvec->bv_offset;
80			length -= avail;
81			stream->next_in = data + offset;
82			stream->avail_in = avail;
83			offset = 0;
84		}
85
86		if (stream->avail_out == 0) {
87			stream->next_out = squashfs_next_page(output);
88			if (stream->next_out != NULL)
89				stream->avail_out = PAGE_SIZE;
90		}
91
92		if (!zlib_init) {
93			zlib_err = zlib_inflateInit(stream);
94			if (zlib_err != Z_OK) {
95				error = -EIO;
96				break;
97			}
98			zlib_init = 1;
99		}
100
101		zlib_err = zlib_inflate(stream, Z_SYNC_FLUSH);
102		if (zlib_err == Z_STREAM_END)
103			break;
104		if (zlib_err != Z_OK) {
105			error = -EIO;
106			break;
107		}
108	}
109
110	squashfs_finish_page(output);
111
112	if (!error)
113		if (zlib_inflateEnd(stream) != Z_OK)
114			error = -EIO;
115
116	return error ? error : stream->total_out;
117}
118
119const struct squashfs_decompressor squashfs_zlib_comp_ops = {
120	.init = zlib_init,
121	.free = zlib_free,
122	.decompress = zlib_uncompress,
123	.id = ZLIB_COMPRESSION,
124	.name = "zlib",
125	.supported = 1
126};
127
128