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, 2010 |
6 | * Phillip Lougher <phillip@squashfs.org.uk> |
7 | * |
8 | * xz_wrapper.c |
9 | */ |
10 | |
11 | |
12 | #include <linux/mutex.h> |
13 | #include <linux/bio.h> |
14 | #include <linux/slab.h> |
15 | #include <linux/xz.h> |
16 | #include <linux/bitops.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 | struct squashfs_xz { |
25 | struct xz_dec *state; |
26 | struct xz_buf buf; |
27 | }; |
28 | |
29 | struct disk_comp_opts { |
30 | __le32 dictionary_size; |
31 | __le32 flags; |
32 | }; |
33 | |
34 | struct comp_opts { |
35 | int dict_size; |
36 | }; |
37 | |
38 | static void *squashfs_xz_comp_opts(struct squashfs_sb_info *msblk, |
39 | void *buff, int len) |
40 | { |
41 | struct disk_comp_opts *comp_opts = buff; |
42 | struct comp_opts *opts; |
43 | int err = 0, n; |
44 | |
45 | opts = kmalloc(size: sizeof(*opts), GFP_KERNEL); |
46 | if (opts == NULL) { |
47 | err = -ENOMEM; |
48 | goto out2; |
49 | } |
50 | |
51 | if (comp_opts) { |
52 | /* check compressor options are the expected length */ |
53 | if (len < sizeof(*comp_opts)) { |
54 | err = -EIO; |
55 | goto out; |
56 | } |
57 | |
58 | opts->dict_size = le32_to_cpu(comp_opts->dictionary_size); |
59 | |
60 | /* the dictionary size should be 2^n or 2^n+2^(n+1) */ |
61 | n = ffs(opts->dict_size) - 1; |
62 | if (opts->dict_size != (1 << n) && opts->dict_size != (1 << n) + |
63 | (1 << (n + 1))) { |
64 | err = -EIO; |
65 | goto out; |
66 | } |
67 | } else |
68 | /* use defaults */ |
69 | opts->dict_size = max_t(int, msblk->block_size, |
70 | SQUASHFS_METADATA_SIZE); |
71 | |
72 | return opts; |
73 | |
74 | out: |
75 | kfree(objp: opts); |
76 | out2: |
77 | return ERR_PTR(error: err); |
78 | } |
79 | |
80 | |
81 | static void *squashfs_xz_init(struct squashfs_sb_info *msblk, void *buff) |
82 | { |
83 | struct comp_opts *comp_opts = buff; |
84 | struct squashfs_xz *stream; |
85 | int err; |
86 | |
87 | stream = kmalloc(size: sizeof(*stream), GFP_KERNEL); |
88 | if (stream == NULL) { |
89 | err = -ENOMEM; |
90 | goto failed; |
91 | } |
92 | |
93 | stream->state = xz_dec_init(mode: XZ_PREALLOC, dict_max: comp_opts->dict_size); |
94 | if (stream->state == NULL) { |
95 | kfree(objp: stream); |
96 | err = -ENOMEM; |
97 | goto failed; |
98 | } |
99 | |
100 | return stream; |
101 | |
102 | failed: |
103 | ERROR("Failed to initialise xz decompressor\n" ); |
104 | return ERR_PTR(error: err); |
105 | } |
106 | |
107 | |
108 | static void squashfs_xz_free(void *strm) |
109 | { |
110 | struct squashfs_xz *stream = strm; |
111 | |
112 | if (stream) { |
113 | xz_dec_end(s: stream->state); |
114 | kfree(objp: stream); |
115 | } |
116 | } |
117 | |
118 | |
119 | static int squashfs_xz_uncompress(struct squashfs_sb_info *msblk, void *strm, |
120 | struct bio *bio, int offset, int length, |
121 | struct squashfs_page_actor *output) |
122 | { |
123 | struct bvec_iter_all iter_all = {}; |
124 | struct bio_vec *bvec = bvec_init_iter_all(iter_all: &iter_all); |
125 | int total = 0, error = 0; |
126 | struct squashfs_xz *stream = strm; |
127 | |
128 | xz_dec_reset(s: stream->state); |
129 | stream->buf.in_pos = 0; |
130 | stream->buf.in_size = 0; |
131 | stream->buf.out_pos = 0; |
132 | stream->buf.out_size = PAGE_SIZE; |
133 | stream->buf.out = squashfs_first_page(actor: output); |
134 | if (IS_ERR(ptr: stream->buf.out)) { |
135 | error = PTR_ERR(ptr: stream->buf.out); |
136 | goto finish; |
137 | } |
138 | |
139 | for (;;) { |
140 | enum xz_ret xz_err; |
141 | |
142 | if (stream->buf.in_pos == stream->buf.in_size) { |
143 | const void *data; |
144 | int avail; |
145 | |
146 | if (!bio_next_segment(bio, iter: &iter_all)) { |
147 | /* XZ_STREAM_END must be reached. */ |
148 | error = -EIO; |
149 | break; |
150 | } |
151 | |
152 | avail = min(length, ((int)bvec->bv_len) - offset); |
153 | data = bvec_virt(bvec); |
154 | length -= avail; |
155 | stream->buf.in = data + offset; |
156 | stream->buf.in_size = avail; |
157 | stream->buf.in_pos = 0; |
158 | offset = 0; |
159 | } |
160 | |
161 | if (stream->buf.out_pos == stream->buf.out_size) { |
162 | stream->buf.out = squashfs_next_page(actor: output); |
163 | if (IS_ERR(ptr: stream->buf.out)) { |
164 | error = PTR_ERR(ptr: stream->buf.out); |
165 | break; |
166 | } else if (stream->buf.out != NULL) { |
167 | stream->buf.out_pos = 0; |
168 | total += PAGE_SIZE; |
169 | } |
170 | } |
171 | |
172 | xz_err = xz_dec_run(s: stream->state, b: &stream->buf); |
173 | if (xz_err == XZ_STREAM_END) |
174 | break; |
175 | if (xz_err != XZ_OK) { |
176 | error = -EIO; |
177 | break; |
178 | } |
179 | } |
180 | |
181 | finish: |
182 | squashfs_finish_page(actor: output); |
183 | |
184 | return error ? error : total + stream->buf.out_pos; |
185 | } |
186 | |
187 | const struct squashfs_decompressor squashfs_xz_comp_ops = { |
188 | .init = squashfs_xz_init, |
189 | .comp_opts = squashfs_xz_comp_opts, |
190 | .free = squashfs_xz_free, |
191 | .decompress = squashfs_xz_uncompress, |
192 | .id = XZ_COMPRESSION, |
193 | .name = "xz" , |
194 | .alloc_buffer = 1, |
195 | .supported = 1 |
196 | }; |
197 | |