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Albin Tonnerre7dd65fe2010-01-08 14:42:42 -08001/*
2 * LZO decompressor for the Linux kernel. Code borrowed from the lzo
3 * implementation by Markus Franz Xaver Johannes Oberhumer.
4 *
5 * Linux kernel adaptation:
6 * Copyright (C) 2009
7 * Albin Tonnerre, Free Electrons <albin.tonnerre@free-electrons.com>
8 *
9 * Original code:
10 * Copyright (C) 1996-2005 Markus Franz Xaver Johannes Oberhumer
11 * All Rights Reserved.
12 *
13 * lzop and the LZO library are free software; you can redistribute them
14 * and/or modify them under the terms of the GNU General Public License as
15 * published by the Free Software Foundation; either version 2 of
16 * the License, or (at your option) any later version.
17 *
18 * This program is distributed in the hope that it will be useful,
19 * but WITHOUT ANY WARRANTY; without even the implied warranty of
20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
21 * GNU General Public License for more details.
22 *
23 * You should have received a copy of the GNU General Public License
24 * along with this program; see the file COPYING.
25 * If not, write to the Free Software Foundation, Inc.,
26 * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
27 *
28 * Markus F.X.J. Oberhumer
29 * <markus@oberhumer.com>
30 * http://www.oberhumer.com/opensource/lzop/
31 */
32
33#ifdef STATIC
34#include "lzo/lzo1x_decompress.c"
35#else
36#include <linux/slab.h>
37#include <linux/decompress/unlzo.h>
38#endif
39
40#include <linux/types.h>
41#include <linux/lzo.h>
42#include <linux/decompress/mm.h>
43
44#include <linux/compiler.h>
45#include <asm/unaligned.h>
46
47static const unsigned char lzop_magic[] = {
48 0x89, 0x4c, 0x5a, 0x4f, 0x00, 0x0d, 0x0a, 0x1a, 0x0a };
49
50#define LZO_BLOCK_SIZE (256*1024l)
51#define HEADER_HAS_FILTER 0x00000800L
52
53STATIC inline int INIT parse_header(u8 *input, u8 *skip)
54{
55 int l;
56 u8 *parse = input;
57 u8 level = 0;
58 u16 version;
59
60 /* read magic: 9 first bits */
61 for (l = 0; l < 9; l++) {
62 if (*parse++ != lzop_magic[l])
63 return 0;
64 }
65 /* get version (2bytes), skip library version (2),
66 * 'need to be extracted' version (2) and
67 * method (1) */
68 version = get_unaligned_be16(parse);
69 parse += 7;
70 if (version >= 0x0940)
71 level = *parse++;
72 if (get_unaligned_be32(parse) & HEADER_HAS_FILTER)
73 parse += 8; /* flags + filter info */
74 else
75 parse += 4; /* flags */
76
77 /* skip mode and mtime_low */
78 parse += 8;
79 if (version >= 0x0940)
80 parse += 4; /* skip mtime_high */
81
82 l = *parse++;
83 /* don't care about the file name, and skip checksum */
84 parse += l + 4;
85
86 *skip = parse - input;
87 return 1;
88}
89
90STATIC inline int INIT unlzo(u8 *input, int in_len,
91 int (*fill) (void *, unsigned int),
92 int (*flush) (void *, unsigned int),
93 u8 *output, int *posp,
94 void (*error_fn) (char *x))
95{
96 u8 skip = 0, r = 0;
97 u32 src_len, dst_len;
98 size_t tmp;
99 u8 *in_buf, *in_buf_save, *out_buf;
Albin Tonnerreccdb4002010-04-23 13:17:58 -0400100 int ret = -1;
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800101
102 set_error_fn(error_fn);
103
104 if (output) {
105 out_buf = output;
106 } else if (!flush) {
107 error("NULL output pointer and no flush function provided");
108 goto exit;
109 } else {
110 out_buf = malloc(LZO_BLOCK_SIZE);
111 if (!out_buf) {
112 error("Could not allocate output buffer");
113 goto exit;
114 }
115 }
116
117 if (input && fill) {
118 error("Both input pointer and fill function provided, don't know what to do");
119 goto exit_1;
120 } else if (input) {
121 in_buf = input;
122 } else if (!fill || !posp) {
123 error("NULL input pointer and missing position pointer or fill function");
124 goto exit_1;
125 } else {
126 in_buf = malloc(lzo1x_worst_compress(LZO_BLOCK_SIZE));
127 if (!in_buf) {
128 error("Could not allocate input buffer");
129 goto exit_1;
130 }
131 }
132 in_buf_save = in_buf;
133
134 if (posp)
135 *posp = 0;
136
137 if (fill)
138 fill(in_buf, lzo1x_worst_compress(LZO_BLOCK_SIZE));
139
140 if (!parse_header(input, &skip)) {
141 error("invalid header");
142 goto exit_2;
143 }
144 in_buf += skip;
145
146 if (posp)
147 *posp = skip;
148
149 for (;;) {
150 /* read uncompressed block size */
151 dst_len = get_unaligned_be32(in_buf);
152 in_buf += 4;
153
154 /* exit if last block */
155 if (dst_len == 0) {
156 if (posp)
157 *posp += 4;
158 break;
159 }
160
161 if (dst_len > LZO_BLOCK_SIZE) {
162 error("dest len longer than block size");
163 goto exit_2;
164 }
165
166 /* read compressed block size, and skip block checksum info */
167 src_len = get_unaligned_be32(in_buf);
168 in_buf += 8;
169
170 if (src_len <= 0 || src_len > dst_len) {
171 error("file corrupted");
172 goto exit_2;
173 }
174
175 /* decompress */
176 tmp = dst_len;
Albin Tonnerreccdb4002010-04-23 13:17:58 -0400177
178 /* When the input data is not compressed at all,
179 * lzo1x_decompress_safe will fail, so call memcpy()
180 * instead */
181 if (unlikely(dst_len == src_len))
182 memcpy(out_buf, in_buf, src_len);
183 else {
184 r = lzo1x_decompress_safe((u8 *) in_buf, src_len,
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800185 out_buf, &tmp);
186
Albin Tonnerreccdb4002010-04-23 13:17:58 -0400187 if (r != LZO_E_OK || dst_len != tmp) {
188 error("Compressed data violation");
189 goto exit_2;
190 }
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800191 }
192
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800193 if (flush)
194 flush(out_buf, dst_len);
195 if (output)
196 out_buf += dst_len;
197 if (posp)
198 *posp += src_len + 12;
199 if (fill) {
200 in_buf = in_buf_save;
201 fill(in_buf, lzo1x_worst_compress(LZO_BLOCK_SIZE));
202 } else
203 in_buf += src_len;
204 }
205
Albin Tonnerreccdb4002010-04-23 13:17:58 -0400206 ret = 0;
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800207exit_2:
208 if (!input)
209 free(in_buf);
210exit_1:
211 if (!output)
212 free(out_buf);
213exit:
Albin Tonnerreccdb4002010-04-23 13:17:58 -0400214 return ret;
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800215}
216
217#define decompress unlzo