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(error: -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(error: -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(size: sizeof(*stream), GFP_KERNEL); |
58 | if (stream == NULL) |
59 | goto failed; |
60 | stream->input = vmalloc(size: block_size); |
61 | if (stream->input == NULL) |
62 | goto failed2; |
63 | stream->output = vmalloc(size: block_size); |
64 | if (stream->output == NULL) |
65 | goto failed3; |
66 | |
67 | return stream; |
68 | |
69 | failed3: |
70 | vfree(addr: stream->input); |
71 | failed2: |
72 | kfree(objp: stream); |
73 | failed: |
74 | ERROR("Failed to initialise LZ4 decompressor\n" ); |
75 | return ERR_PTR(error: -ENOMEM); |
76 | } |
77 | |
78 | |
79 | static void lz4_free(void *strm) |
80 | { |
81 | struct squashfs_lz4 *stream = strm; |
82 | |
83 | if (stream) { |
84 | vfree(addr: stream->input); |
85 | vfree(addr: stream->output); |
86 | } |
87 | kfree(objp: 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: &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: &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(source: stream->input, dest: stream->output, |
112 | compressedSize: length, maxDecompressedSize: output->length); |
113 | |
114 | if (res < 0) |
115 | return -EIO; |
116 | |
117 | bytes = res; |
118 | data = squashfs_first_page(actor: output); |
119 | buff = stream->output; |
120 | while (data) { |
121 | if (bytes <= PAGE_SIZE) { |
122 | if (!IS_ERR(ptr: data)) |
123 | memcpy(data, buff, bytes); |
124 | break; |
125 | } |
126 | if (!IS_ERR(ptr: data)) |
127 | memcpy(data, buff, PAGE_SIZE); |
128 | buff += PAGE_SIZE; |
129 | bytes -= PAGE_SIZE; |
130 | data = squashfs_next_page(actor: output); |
131 | } |
132 | squashfs_finish_page(actor: 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 | |