2 * LZO decompressor for the Linux kernel. Code borrowed from the lzo
3 * implementation by Markus Franz Xaver Johannes Oberhumer.
5 * Linux kernel adaptation:
7 * Albin Tonnerre, Free Electrons <albin.tonnerre@free-electrons.com>
10 * Copyright (C) 1996-2005 Markus Franz Xaver Johannes Oberhumer
11 * All Rights Reserved.
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.
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.
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.
28 * Markus F.X.J. Oberhumer
29 * <markus@oberhumer.com>
30 * http://www.oberhumer.com/opensource/lzop/
35 #include "lzo/lzo1x_decompress_safe.c"
37 #include <linux/decompress/unlzo.h>
40 #include <linux/types.h>
41 #include <linux/lzo.h>
42 #include <linux/decompress/mm.h>
44 #include <linux/compiler.h>
45 #include <asm/unaligned.h>
47 static const unsigned char lzop_magic[] = {
48 0x89, 0x4c, 0x5a, 0x4f, 0x00, 0x0d, 0x0a, 0x1a, 0x0a };
50 #define LZO_BLOCK_SIZE (256*1024l)
51 #define HEADER_HAS_FILTER 0x00000800L
52 #define HEADER_SIZE_MIN (9 + 7 + 4 + 8 + 1 + 4)
53 #define HEADER_SIZE_MAX (9 + 7 + 1 + 8 + 8 + 4 + 1 + 255 + 4)
55 STATIC inline long INIT parse_header(u8 *input, long *skip, long in_len)
59 u8 *end = input + in_len;
64 * Check that there's enough input to possibly have a valid header.
65 * Then it is possible to parse several fields until the minimum
66 * size may have been used.
68 if (in_len < HEADER_SIZE_MIN)
71 /* read magic: 9 first bits */
72 for (l = 0; l < 9; l++) {
73 if (*parse++ != lzop_magic[l])
76 /* get version (2bytes), skip library version (2),
77 * 'need to be extracted' version (2) and
79 version = get_unaligned_be16(parse);
81 if (version >= 0x0940)
83 if (get_unaligned_be32(parse) & HEADER_HAS_FILTER)
84 parse += 8; /* flags + filter info */
86 parse += 4; /* flags */
89 * At least mode, mtime_low, filename length, and checksum must
90 * be left to be parsed. If also mtime_high is present, it's OK
91 * because the next input buffer check is after reading the
94 if (end - parse < 8 + 1 + 4)
97 /* skip mode and mtime_low */
99 if (version >= 0x0940)
100 parse += 4; /* skip mtime_high */
103 /* don't care about the file name, and skip checksum */
104 if (end - parse < l + 4)
108 *skip = parse - input;
112 STATIC int INIT unlzo(u8 *input, long in_len,
113 long (*fill)(void *, unsigned long),
114 long (*flush)(void *, unsigned long),
115 u8 *output, long *posp,
116 void (*error) (char *x))
120 u32 src_len, dst_len;
122 u8 *in_buf, *in_buf_save, *out_buf;
128 error("NULL output pointer and no flush function provided");
131 out_buf = malloc(LZO_BLOCK_SIZE);
133 error("Could not allocate output buffer");
139 error("Both input pointer and fill function provided, don't know what to do");
144 error("NULL input pointer and missing fill function");
147 in_buf = malloc(lzo1x_worst_compress(LZO_BLOCK_SIZE));
149 error("Could not allocate input buffer");
153 in_buf_save = in_buf;
160 * Start from in_buf + HEADER_SIZE_MAX to make it possible
161 * to use memcpy() to copy the unused data to the beginning
162 * of the buffer. This way memmove() isn't needed which
163 * is missing from pre-boot environments of most archs.
165 in_buf += HEADER_SIZE_MAX;
166 in_len = fill(in_buf, HEADER_SIZE_MAX);
169 if (!parse_header(in_buf, &skip, in_len)) {
170 error("invalid header");
177 /* Move the unused data to the beginning of the buffer. */
178 memcpy(in_buf_save, in_buf, in_len);
179 in_buf = in_buf_save;
186 /* read uncompressed block size */
187 if (fill && in_len < 4) {
188 skip = fill(in_buf + in_len, 4 - in_len);
193 error("file corrupted");
196 dst_len = get_unaligned_be32(in_buf);
200 /* exit if last block */
207 if (dst_len > LZO_BLOCK_SIZE) {
208 error("dest len longer than block size");
212 /* read compressed block size, and skip block checksum info */
213 if (fill && in_len < 8) {
214 skip = fill(in_buf + in_len, 8 - in_len);
219 error("file corrupted");
222 src_len = get_unaligned_be32(in_buf);
226 if (src_len <= 0 || src_len > dst_len) {
227 error("file corrupted");
232 if (fill && in_len < src_len) {
233 skip = fill(in_buf + in_len, src_len - in_len);
237 if (in_len < src_len) {
238 error("file corrupted");
243 /* When the input data is not compressed at all,
244 * lzo1x_decompress_safe will fail, so call memcpy()
246 if (unlikely(dst_len == src_len))
247 memcpy(out_buf, in_buf, src_len);
249 r = lzo1x_decompress_safe((u8 *) in_buf, src_len,
252 if (r != LZO_E_OK || dst_len != tmp) {
253 error("Compressed data violation");
258 if (flush && flush(out_buf, dst_len) != dst_len)
263 *posp += src_len + 12;
269 * If there happens to still be unused data left in
270 * in_buf, move it to the beginning of the buffer.
271 * Use a loop to avoid memmove() dependency.
274 for (skip = 0; skip < in_len; ++skip)
275 in_buf_save[skip] = in_buf[skip];
276 in_buf = in_buf_save;
292 STATIC int INIT __decompress(unsigned char *buf, long len,
293 long (*fill)(void*, unsigned long),
294 long (*flush)(void*, unsigned long),
295 unsigned char *out_buf, long olen,
297 void (*error)(char *x))
299 return unlzo(buf, len, fill, flush, out_buf, pos, error);