1 /* 2 * QEMU Block driver for DMG images 3 * 4 * Copyright (c) 2004 Johannes E. Schindelin 5 * 6 * Permission is hereby granted, free of charge, to any person obtaining a copy 7 * of this software and associated documentation files (the "Software"), to deal 8 * in the Software without restriction, including without limitation the rights 9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 10 * copies of the Software, and to permit persons to whom the Software is 11 * furnished to do so, subject to the following conditions: 12 * 13 * The above copyright notice and this permission notice shall be included in 14 * all copies or substantial portions of the Software. 15 * 16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 22 * THE SOFTWARE. 23 */ 24 #include "qemu-common.h" 25 #include "block/block_int.h" 26 #include "qemu/bswap.h" 27 #include "qemu/module.h" 28 #include <zlib.h> 29 30 typedef struct BDRVDMGState { 31 CoMutex lock; 32 /* each chunk contains a certain number of sectors, 33 * offsets[i] is the offset in the .dmg file, 34 * lengths[i] is the length of the compressed chunk, 35 * sectors[i] is the sector beginning at offsets[i], 36 * sectorcounts[i] is the number of sectors in that chunk, 37 * the sectors array is ordered 38 * 0<=i<n_chunks */ 39 40 uint32_t n_chunks; 41 uint32_t* types; 42 uint64_t* offsets; 43 uint64_t* lengths; 44 uint64_t* sectors; 45 uint64_t* sectorcounts; 46 uint32_t current_chunk; 47 uint8_t *compressed_chunk; 48 uint8_t *uncompressed_chunk; 49 z_stream zstream; 50 } BDRVDMGState; 51 52 static int dmg_probe(const uint8_t *buf, int buf_size, const char *filename) 53 { 54 int len=strlen(filename); 55 if(len>4 && !strcmp(filename+len-4,".dmg")) 56 return 2; 57 return 0; 58 } 59 60 static int read_uint64(BlockDriverState *bs, int64_t offset, uint64_t *result) 61 { 62 uint64_t buffer; 63 int ret; 64 65 ret = bdrv_pread(bs->file, offset, &buffer, 8); 66 if (ret < 0) { 67 return ret; 68 } 69 70 *result = be64_to_cpu(buffer); 71 return 0; 72 } 73 74 static int read_uint32(BlockDriverState *bs, int64_t offset, uint32_t *result) 75 { 76 uint32_t buffer; 77 int ret; 78 79 ret = bdrv_pread(bs->file, offset, &buffer, 4); 80 if (ret < 0) { 81 return ret; 82 } 83 84 *result = be32_to_cpu(buffer); 85 return 0; 86 } 87 88 static int dmg_open(BlockDriverState *bs, int flags) 89 { 90 BDRVDMGState *s = bs->opaque; 91 uint64_t info_begin,info_end,last_in_offset,last_out_offset; 92 uint32_t count, tmp; 93 uint32_t max_compressed_size=1,max_sectors_per_chunk=1,i; 94 int64_t offset; 95 int ret; 96 97 bs->read_only = 1; 98 s->n_chunks = 0; 99 s->offsets = s->lengths = s->sectors = s->sectorcounts = NULL; 100 101 /* read offset of info blocks */ 102 offset = bdrv_getlength(bs->file); 103 if (offset < 0) { 104 ret = offset; 105 goto fail; 106 } 107 offset -= 0x1d8; 108 109 ret = read_uint64(bs, offset, &info_begin); 110 if (ret < 0) { 111 goto fail; 112 } else if (info_begin == 0) { 113 ret = -EINVAL; 114 goto fail; 115 } 116 117 ret = read_uint32(bs, info_begin, &tmp); 118 if (ret < 0) { 119 goto fail; 120 } else if (tmp != 0x100) { 121 ret = -EINVAL; 122 goto fail; 123 } 124 125 ret = read_uint32(bs, info_begin + 4, &count); 126 if (ret < 0) { 127 goto fail; 128 } else if (count == 0) { 129 ret = -EINVAL; 130 goto fail; 131 } 132 info_end = info_begin + count; 133 134 offset = info_begin + 0x100; 135 136 /* read offsets */ 137 last_in_offset = last_out_offset = 0; 138 while (offset < info_end) { 139 uint32_t type; 140 141 ret = read_uint32(bs, offset, &count); 142 if (ret < 0) { 143 goto fail; 144 } else if (count == 0) { 145 ret = -EINVAL; 146 goto fail; 147 } 148 offset += 4; 149 150 ret = read_uint32(bs, offset, &type); 151 if (ret < 0) { 152 goto fail; 153 } 154 155 if (type == 0x6d697368 && count >= 244) { 156 int new_size, chunk_count; 157 158 offset += 4; 159 offset += 200; 160 161 chunk_count = (count-204)/40; 162 new_size = sizeof(uint64_t) * (s->n_chunks + chunk_count); 163 s->types = g_realloc(s->types, new_size/2); 164 s->offsets = g_realloc(s->offsets, new_size); 165 s->lengths = g_realloc(s->lengths, new_size); 166 s->sectors = g_realloc(s->sectors, new_size); 167 s->sectorcounts = g_realloc(s->sectorcounts, new_size); 168 169 for (i = s->n_chunks; i < s->n_chunks + chunk_count; i++) { 170 ret = read_uint32(bs, offset, &s->types[i]); 171 if (ret < 0) { 172 goto fail; 173 } 174 offset += 4; 175 if(s->types[i]!=0x80000005 && s->types[i]!=1 && s->types[i]!=2) { 176 if(s->types[i]==0xffffffff) { 177 last_in_offset = s->offsets[i-1]+s->lengths[i-1]; 178 last_out_offset = s->sectors[i-1]+s->sectorcounts[i-1]; 179 } 180 chunk_count--; 181 i--; 182 offset += 36; 183 continue; 184 } 185 offset += 4; 186 187 ret = read_uint64(bs, offset, &s->sectors[i]); 188 if (ret < 0) { 189 goto fail; 190 } 191 s->sectors[i] += last_out_offset; 192 offset += 8; 193 194 ret = read_uint64(bs, offset, &s->sectorcounts[i]); 195 if (ret < 0) { 196 goto fail; 197 } 198 offset += 8; 199 200 ret = read_uint64(bs, offset, &s->offsets[i]); 201 if (ret < 0) { 202 goto fail; 203 } 204 s->offsets[i] += last_in_offset; 205 offset += 8; 206 207 ret = read_uint64(bs, offset, &s->lengths[i]); 208 if (ret < 0) { 209 goto fail; 210 } 211 offset += 8; 212 213 if(s->lengths[i]>max_compressed_size) 214 max_compressed_size = s->lengths[i]; 215 if(s->sectorcounts[i]>max_sectors_per_chunk) 216 max_sectors_per_chunk = s->sectorcounts[i]; 217 } 218 s->n_chunks+=chunk_count; 219 } 220 } 221 222 /* initialize zlib engine */ 223 s->compressed_chunk = g_malloc(max_compressed_size+1); 224 s->uncompressed_chunk = g_malloc(512*max_sectors_per_chunk); 225 if(inflateInit(&s->zstream) != Z_OK) { 226 ret = -EINVAL; 227 goto fail; 228 } 229 230 s->current_chunk = s->n_chunks; 231 232 qemu_co_mutex_init(&s->lock); 233 return 0; 234 235 fail: 236 g_free(s->types); 237 g_free(s->offsets); 238 g_free(s->lengths); 239 g_free(s->sectors); 240 g_free(s->sectorcounts); 241 g_free(s->compressed_chunk); 242 g_free(s->uncompressed_chunk); 243 return ret; 244 } 245 246 static inline int is_sector_in_chunk(BDRVDMGState* s, 247 uint32_t chunk_num,int sector_num) 248 { 249 if(chunk_num>=s->n_chunks || s->sectors[chunk_num]>sector_num || 250 s->sectors[chunk_num]+s->sectorcounts[chunk_num]<=sector_num) 251 return 0; 252 else 253 return -1; 254 } 255 256 static inline uint32_t search_chunk(BDRVDMGState* s,int sector_num) 257 { 258 /* binary search */ 259 uint32_t chunk1=0,chunk2=s->n_chunks,chunk3; 260 while(chunk1!=chunk2) { 261 chunk3 = (chunk1+chunk2)/2; 262 if(s->sectors[chunk3]>sector_num) 263 chunk2 = chunk3; 264 else if(s->sectors[chunk3]+s->sectorcounts[chunk3]>sector_num) 265 return chunk3; 266 else 267 chunk1 = chunk3; 268 } 269 return s->n_chunks; /* error */ 270 } 271 272 static inline int dmg_read_chunk(BlockDriverState *bs, int sector_num) 273 { 274 BDRVDMGState *s = bs->opaque; 275 276 if(!is_sector_in_chunk(s,s->current_chunk,sector_num)) { 277 int ret; 278 uint32_t chunk = search_chunk(s,sector_num); 279 280 if(chunk>=s->n_chunks) 281 return -1; 282 283 s->current_chunk = s->n_chunks; 284 switch(s->types[chunk]) { 285 case 0x80000005: { /* zlib compressed */ 286 int i; 287 288 /* we need to buffer, because only the chunk as whole can be 289 * inflated. */ 290 i=0; 291 do { 292 ret = bdrv_pread(bs->file, s->offsets[chunk] + i, 293 s->compressed_chunk+i, s->lengths[chunk]-i); 294 if(ret<0 && errno==EINTR) 295 ret=0; 296 i+=ret; 297 } while(ret>=0 && ret+i<s->lengths[chunk]); 298 299 if (ret != s->lengths[chunk]) 300 return -1; 301 302 s->zstream.next_in = s->compressed_chunk; 303 s->zstream.avail_in = s->lengths[chunk]; 304 s->zstream.next_out = s->uncompressed_chunk; 305 s->zstream.avail_out = 512*s->sectorcounts[chunk]; 306 ret = inflateReset(&s->zstream); 307 if(ret != Z_OK) 308 return -1; 309 ret = inflate(&s->zstream, Z_FINISH); 310 if(ret != Z_STREAM_END || s->zstream.total_out != 512*s->sectorcounts[chunk]) 311 return -1; 312 break; } 313 case 1: /* copy */ 314 ret = bdrv_pread(bs->file, s->offsets[chunk], 315 s->uncompressed_chunk, s->lengths[chunk]); 316 if (ret != s->lengths[chunk]) 317 return -1; 318 break; 319 case 2: /* zero */ 320 memset(s->uncompressed_chunk, 0, 512*s->sectorcounts[chunk]); 321 break; 322 } 323 s->current_chunk = chunk; 324 } 325 return 0; 326 } 327 328 static int dmg_read(BlockDriverState *bs, int64_t sector_num, 329 uint8_t *buf, int nb_sectors) 330 { 331 BDRVDMGState *s = bs->opaque; 332 int i; 333 334 for(i=0;i<nb_sectors;i++) { 335 uint32_t sector_offset_in_chunk; 336 if(dmg_read_chunk(bs, sector_num+i) != 0) 337 return -1; 338 sector_offset_in_chunk = sector_num+i-s->sectors[s->current_chunk]; 339 memcpy(buf+i*512,s->uncompressed_chunk+sector_offset_in_chunk*512,512); 340 } 341 return 0; 342 } 343 344 static coroutine_fn int dmg_co_read(BlockDriverState *bs, int64_t sector_num, 345 uint8_t *buf, int nb_sectors) 346 { 347 int ret; 348 BDRVDMGState *s = bs->opaque; 349 qemu_co_mutex_lock(&s->lock); 350 ret = dmg_read(bs, sector_num, buf, nb_sectors); 351 qemu_co_mutex_unlock(&s->lock); 352 return ret; 353 } 354 355 static void dmg_close(BlockDriverState *bs) 356 { 357 BDRVDMGState *s = bs->opaque; 358 359 g_free(s->types); 360 g_free(s->offsets); 361 g_free(s->lengths); 362 g_free(s->sectors); 363 g_free(s->sectorcounts); 364 g_free(s->compressed_chunk); 365 g_free(s->uncompressed_chunk); 366 367 inflateEnd(&s->zstream); 368 } 369 370 static BlockDriver bdrv_dmg = { 371 .format_name = "dmg", 372 .instance_size = sizeof(BDRVDMGState), 373 .bdrv_probe = dmg_probe, 374 .bdrv_open = dmg_open, 375 .bdrv_read = dmg_co_read, 376 .bdrv_close = dmg_close, 377 }; 378 379 static void bdrv_dmg_init(void) 380 { 381 bdrv_register(&bdrv_dmg); 382 } 383 384 block_init(bdrv_dmg_init); 385