1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (c) 2013, 2014
4 * Phillip Lougher <phillip@squashfs.org.uk>
5 */
6
7 #include <linux/bio.h>
8 #include <linux/mutex.h>
9 #include <linux/slab.h>
10 #include <linux/vmalloc.h>
11 #include <linux/lz4.h>
12
13 #include "squashfs_fs.h"
14 #include "squashfs_fs_sb.h"
15 #include "squashfs.h"
16 #include "decompressor.h"
17 #include "page_actor.h"
18
19 #define LZ4_LEGACY 1
20
21 struct lz4_comp_opts {
22 __le32 version;
23 __le32 flags;
24 };
25
26 struct squashfs_lz4 {
27 void *input;
28 void *output;
29 };
30
31
32 static void *lz4_comp_opts(struct squashfs_sb_info *msblk,
33 void *buff, int len)
34 {
35 struct lz4_comp_opts *comp_opts = buff;
36
37 /* LZ4 compressed filesystems always have compression options */
38 if (comp_opts == NULL || len < sizeof(*comp_opts))
39 return ERR_PTR(-EIO);
40
41 if (le32_to_cpu(comp_opts->version) != LZ4_LEGACY) {
42 /* LZ4 format currently used by the kernel is the 'legacy'
43 * format */
44 ERROR("Unknown LZ4 version\n");
45 return ERR_PTR(-EINVAL);
46 }
47
48 return NULL;
49 }
50
51
52 static void *lz4_init(struct squashfs_sb_info *msblk, void *buff)
53 {
54 int block_size = max_t(int, msblk->block_size, SQUASHFS_METADATA_SIZE);
55 struct squashfs_lz4 *stream;
56
57 stream = kzalloc(sizeof(*stream), GFP_KERNEL);
58 if (stream == NULL)
59 goto failed;
60 stream->input = vmalloc(block_size);
61 if (stream->input == NULL)
62 goto failed2;
63 stream->output = vmalloc(block_size);
64 if (stream->output == NULL)
65 goto failed3;
66
67 return stream;
68
69 failed3:
70 vfree(stream->input);
71 failed2:
72 kfree(stream);
73 failed:
74 ERROR("Failed to initialise LZ4 decompressor\n");
75 return ERR_PTR(-ENOMEM);
76 }
77
78
79 static void lz4_free(void *strm)
80 {
81 struct squashfs_lz4 *stream = strm;
82
83 if (stream) {
84 vfree(stream->input);
85 vfree(stream->output);
86 }
87 kfree(stream);
88 }
89
90
91 static int lz4_uncompress(struct squashfs_sb_info *msblk, void *strm,
92 struct bio *bio, int offset, int length,
93 struct squashfs_page_actor *output)
94 {
95 struct bvec_iter_all iter_all = {};
96 struct bio_vec *bvec = bvec_init_iter_all(&iter_all);
97 struct squashfs_lz4 *stream = strm;
98 void *buff = stream->input, *data;
99 int bytes = length, res;
100
101 while (bio_next_segment(bio, &iter_all)) {
102 int avail = min(bytes, ((int)bvec->bv_len) - offset);
103
104 data = bvec_virt(bvec);
105 memcpy(buff, data + offset, avail);
106 buff += avail;
107 bytes -= avail;
108 offset = 0;
109 }
110
111 res = LZ4_decompress_safe(stream->input, stream->output,
112 length, output->length);
113
114 if (res < 0)
115 return -EIO;
116
117 bytes = res;
118 data = squashfs_first_page(output);
119 buff = stream->output;
120 while (data) {
121 if (bytes <= PAGE_SIZE) {
122 if (!IS_ERR(data))
123 memcpy(data, buff, bytes);
124 break;
125 }
126 if (!IS_ERR(data))
127 memcpy(data, buff, PAGE_SIZE);
128 buff += PAGE_SIZE;
129 bytes -= PAGE_SIZE;
130 data = squashfs_next_page(output);
131 }
132 squashfs_finish_page(output);
133
134 return res;
135 }
136
137 const struct squashfs_decompressor squashfs_lz4_comp_ops = {
138 .init = lz4_init,
139 .comp_opts = lz4_comp_opts,
140 .free = lz4_free,
141 .decompress = lz4_uncompress,
142 .id = LZ4_COMPRESSION,
143 .name = "lz4",
144 .alloc_buffer = 0,
145 .supported = 1
146 };
147
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