lib/decompress_unlzo.c

   1 /*
   2  * LZO decompressor for barebox. 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 #include <common.h>
  34 #include <malloc.h>
  35 #include <linux/types.h>
  36 #include <lzo.h>
  37 #include <errno.h>
  38 #include <fs.h>
  39 #include <xfuncs.h>
  40
  41 #include <linux/compiler.h>
  42 #include <asm/unaligned.h>
  43
  44 static const unsigned char lzop_magic[] = {
  45         0x89, 0x4c, 0x5a, 0x4f, 0x00, 0x0d, 0x0a, 0x1a, 0x0a };
  46
  47 #define LZO_BLOCK_SIZE        (256*1024l)
  48 #define HEADER_HAS_FILTER      0x00000800L
  49
  50 static inline int parse_header(int in_fd)
  51 {
  52         u8 l;
  53         u16 version;
  54         int ret;
  55         unsigned char buf[256]; /* maximum filename length + 1 */
  56
  57         /* read magic (9), library version (2), 'need to be extracted'
  58          * version (2) and method (1)
  59          */
  60         ret = read(in_fd, buf, 9);
  61         if (ret < 0)
  62                 return ret;
  63
  64         /* check magic */
  65         for (l = 0; l < 9; l++) {
  66                 if (buf[l] != lzop_magic[l])
  67                         return -EINVAL;
  68         }
  69
  70         ret = read(in_fd, buf, 4); /* version, lib_version */
  71         if (ret < 0)
  72                 return ret;
  73         version = get_unaligned_be16(buf);
  74
  75         if (version >= 0x0940) {
  76                 ret = read(in_fd, buf, 2); /* version to extract */
  77                 if (ret < 0)
  78                         return ret;
  79         }
  80
  81         ret = read(in_fd, buf, 1); /* method */
  82         if (ret < 0)
  83                 return ret;
  84
  85         if (version >= 0x0940)
  86                 read(in_fd, buf, 1); /* level */
  87
  88         ret = read(in_fd, buf, 4); /* flags */
  89         if (ret < 0)
  90                 return ret;
  91
  92         if (get_unaligned_be32(buf) & HEADER_HAS_FILTER) {
  93                 ret = read(in_fd, buf, 4); /* skip filter info */
  94                 if (ret < 0)
  95                         return ret;
  96         }
  97
  98         /* skip mode and mtime_low */
  99         ret = read(in_fd, buf, 8);
 100         if (ret < 0)
 101                 return ret;
 102
 103         if (version >= 0x0940) {
 104                 ret = read(in_fd, buf, 4); /* skip mtime_high */
 105                 if (ret < 0)
 106                         return ret;
 107         }
 108
 109         ret = read(in_fd, &l, 1);
 110         if (ret < 0)
 111                 return ret;
 112         /* don't care about the file name, and skip checksum */
 113         ret = read(in_fd, buf, l + 4);
 114         if (ret < 0)
 115                 return ret;
 116
 117         return 0;
 118 }
 119
 120 int unlzo(int in_fd, int out_fd, int *dest_len)
 121 {
 122         u8 r = 0;
 123         u32 src_len, dst_len;
 124         size_t tmp;
 125         u8 *in_buf, *out_buf;
 126         int obytes_processed = 0;
 127         unsigned char buf[8];
 128         int ret;
 129
 130         if (parse_header(in_fd))
 131                 return -EINVAL;
 132
 133         out_buf = xmalloc(LZO_BLOCK_SIZE);
 134         in_buf = xmalloc(lzo1x_worst_compress(LZO_BLOCK_SIZE));
 135
 136         for (;;) {
 137                 /* read uncompressed block size */
 138                 ret = read(in_fd, buf, 4);
 139                 if (ret < 0)
 140                         goto exit_free;
 141                 dst_len = get_unaligned_be32(buf);
 142
 143                 /* exit if last block */
 144                 if (dst_len == 0)
 145                         break;
 146
 147                 if (dst_len > LZO_BLOCK_SIZE) {
 148                         printf("dest len longer than block size");
 149                         goto exit_free;
 150                 }
 151
 152                 /* read compressed block size, and skip block checksum info */
 153                 ret = read(in_fd, buf, 8);
 154                 if (ret < 0)
 155                         goto exit_free;
 156
 157                 src_len = get_unaligned_be32(buf);
 158
 159                 if (src_len <= 0 || src_len > dst_len) {
 160                         printf("file corrupted");
 161                         goto exit_free;
 162                 }
 163                 ret = read(in_fd, in_buf, src_len);
 164                 if (ret < 0)
 165                         goto exit_free;
 166
 167                 /* decompress */
 168                 tmp = dst_len;
 169                 if (src_len < dst_len) {
 170                         r = lzo1x_decompress_safe((u8 *) in_buf, src_len,
 171                                                 out_buf, &tmp);
 172                         if (r != LZO_E_OK || dst_len != tmp) {
 173                                 printf("Compressed data violation");
 174                                 goto exit_free;
 175                         }
 176                         ret = write(out_fd, out_buf, dst_len);
 177                         if (ret < 0)
 178                                 goto exit_free;
 179                 } else {
 180                         if (src_len != dst_len) {
 181                                 printf("Compressed data violation");
 182                                 goto exit_free;
 183                         }
 184                         ret = write(out_fd, in_buf, dst_len);
 185                         if (ret < 0)
 186                                 goto exit_free;
 187                 }
 188
 189                 obytes_processed += dst_len;
 190         }
 191
 192 exit_free:
 193         free(in_buf);
 194         free(out_buf);
 195
 196         *dest_len = obytes_processed;
 197         return 0;
 198 }
 199