1 /* 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 47 static 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 53 STATIC 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 90 STATIC 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; 100 int obytes_processed = 0; 101 102 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; 177 r = lzo1x_decompress_safe((u8 *) in_buf, src_len, 178 out_buf, &tmp); 179 180 if (r != LZO_E_OK || dst_len != tmp) { 181 error("Compressed data violation"); 182 goto exit_2; 183 } 184 185 obytes_processed += dst_len; 186 if (flush) 187 flush(out_buf, dst_len); 188 if (output) 189 out_buf += dst_len; 190 if (posp) 191 *posp += src_len + 12; 192 if (fill) { 193 in_buf = in_buf_save; 194 fill(in_buf, lzo1x_worst_compress(LZO_BLOCK_SIZE)); 195 } else 196 in_buf += src_len; 197 } 198 199 exit_2: 200 if (!input) 201 free(in_buf); 202 exit_1: 203 if (!output) 204 free(out_buf); 205 exit: 206 return obytes_processed; 207 } 208 209 #define decompress unlzo 210