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/osdep.h" 25 #include "qapi/error.h" 26 #include "block/block_int.h" 27 #include "qemu/bswap.h" 28 #include "qemu/error-report.h" 29 #include "qemu/module.h" 30 #include "qemu/memalign.h" 31 #include "dmg.h" 32 33 int (*dmg_uncompress_bz2)(char *next_in, unsigned int avail_in, 34 char *next_out, unsigned int avail_out); 35 36 int (*dmg_uncompress_lzfse)(char *next_in, unsigned int avail_in, 37 char *next_out, unsigned int avail_out); 38 39 enum { 40 /* Limit chunk sizes to prevent unreasonable amounts of memory being used 41 * or truncating when converting to 32-bit types 42 */ 43 DMG_LENGTHS_MAX = 64 * 1024 * 1024, /* 64 MB */ 44 DMG_SECTORCOUNTS_MAX = DMG_LENGTHS_MAX / 512, 45 }; 46 47 enum { 48 /* DMG Block Type */ 49 UDZE = 0, /* Zeroes */ 50 UDRW, /* RAW type */ 51 UDIG, /* Ignore */ 52 UDCO = 0x80000004, 53 UDZO, 54 UDBZ, 55 ULFO, 56 UDCM = 0x7ffffffe, /* Comments */ 57 UDLE = 0xffffffff /* Last Entry */ 58 }; 59 60 static int dmg_probe(const uint8_t *buf, int buf_size, const char *filename) 61 { 62 int len; 63 64 if (!filename) { 65 return 0; 66 } 67 68 len = strlen(filename); 69 if (len > 4 && !strcmp(filename + len - 4, ".dmg")) { 70 return 2; 71 } 72 return 0; 73 } 74 75 static int read_uint64(BlockDriverState *bs, int64_t offset, uint64_t *result) 76 { 77 uint64_t buffer; 78 int ret; 79 80 ret = bdrv_pread(bs->file, offset, 8, &buffer, 0); 81 if (ret < 0) { 82 return ret; 83 } 84 85 *result = be64_to_cpu(buffer); 86 return 0; 87 } 88 89 static int read_uint32(BlockDriverState *bs, int64_t offset, uint32_t *result) 90 { 91 uint32_t buffer; 92 int ret; 93 94 ret = bdrv_pread(bs->file, offset, 4, &buffer, 0); 95 if (ret < 0) { 96 return ret; 97 } 98 99 *result = be32_to_cpu(buffer); 100 return 0; 101 } 102 103 static inline uint64_t buff_read_uint64(const uint8_t *buffer, int64_t offset) 104 { 105 return be64_to_cpu(*(uint64_t *)&buffer[offset]); 106 } 107 108 static inline uint32_t buff_read_uint32(const uint8_t *buffer, int64_t offset) 109 { 110 return be32_to_cpu(*(uint32_t *)&buffer[offset]); 111 } 112 113 /* Increase max chunk sizes, if necessary. This function is used to calculate 114 * the buffer sizes needed for compressed/uncompressed chunk I/O. 115 */ 116 static void update_max_chunk_size(BDRVDMGState *s, uint32_t chunk, 117 uint32_t *max_compressed_size, 118 uint32_t *max_sectors_per_chunk) 119 { 120 uint32_t compressed_size = 0; 121 uint32_t uncompressed_sectors = 0; 122 123 switch (s->types[chunk]) { 124 case UDZO: /* zlib compressed */ 125 case UDBZ: /* bzip2 compressed */ 126 case ULFO: /* lzfse compressed */ 127 compressed_size = s->lengths[chunk]; 128 uncompressed_sectors = s->sectorcounts[chunk]; 129 break; 130 case UDRW: /* copy */ 131 uncompressed_sectors = DIV_ROUND_UP(s->lengths[chunk], 512); 132 break; 133 case UDZE: /* zero */ 134 case UDIG: /* ignore */ 135 /* as the all-zeroes block may be large, it is treated specially: the 136 * sector is not copied from a large buffer, a simple memset is used 137 * instead. Therefore uncompressed_sectors does not need to be set. */ 138 break; 139 } 140 141 if (compressed_size > *max_compressed_size) { 142 *max_compressed_size = compressed_size; 143 } 144 if (uncompressed_sectors > *max_sectors_per_chunk) { 145 *max_sectors_per_chunk = uncompressed_sectors; 146 } 147 } 148 149 static int64_t dmg_find_koly_offset(BdrvChild *file, Error **errp) 150 { 151 BlockDriverState *file_bs = file->bs; 152 int64_t length; 153 int64_t offset = 0; 154 uint8_t buffer[515]; 155 int i, ret; 156 157 /* bdrv_getlength returns a multiple of block size (512), rounded up. Since 158 * dmg images can have odd sizes, try to look for the "koly" magic which 159 * marks the begin of the UDIF trailer (512 bytes). This magic can be found 160 * in the last 511 bytes of the second-last sector or the first 4 bytes of 161 * the last sector (search space: 515 bytes) */ 162 length = bdrv_getlength(file_bs); 163 if (length < 0) { 164 error_setg_errno(errp, -length, 165 "Failed to get file size while reading UDIF trailer"); 166 return length; 167 } else if (length < 512) { 168 error_setg(errp, "dmg file must be at least 512 bytes long"); 169 return -EINVAL; 170 } 171 if (length > 511 + 512) { 172 offset = length - 511 - 512; 173 } 174 length = length < 515 ? length : 515; 175 ret = bdrv_pread(file, offset, length, buffer, 0); 176 if (ret < 0) { 177 error_setg_errno(errp, -ret, "Failed while reading UDIF trailer"); 178 return ret; 179 } 180 for (i = 0; i < length - 3; i++) { 181 if (buffer[i] == 'k' && buffer[i+1] == 'o' && 182 buffer[i+2] == 'l' && buffer[i+3] == 'y') { 183 return offset + i; 184 } 185 } 186 error_setg(errp, "Could not locate UDIF trailer in dmg file"); 187 return -EINVAL; 188 } 189 190 /* used when building the sector table */ 191 typedef struct DmgHeaderState { 192 /* used internally by dmg_read_mish_block to remember offsets of blocks 193 * across calls */ 194 uint64_t data_fork_offset; 195 /* exported for dmg_open */ 196 uint32_t max_compressed_size; 197 uint32_t max_sectors_per_chunk; 198 } DmgHeaderState; 199 200 static bool dmg_is_known_block_type(uint32_t entry_type) 201 { 202 switch (entry_type) { 203 case UDZE: /* zeros */ 204 case UDRW: /* uncompressed */ 205 case UDIG: /* ignore */ 206 case UDZO: /* zlib */ 207 return true; 208 case UDBZ: /* bzip2 */ 209 return !!dmg_uncompress_bz2; 210 case ULFO: /* lzfse */ 211 return !!dmg_uncompress_lzfse; 212 default: 213 return false; 214 } 215 } 216 217 static int dmg_read_mish_block(BDRVDMGState *s, DmgHeaderState *ds, 218 uint8_t *buffer, uint32_t count) 219 { 220 uint32_t type, i; 221 int ret; 222 size_t new_size; 223 uint32_t chunk_count; 224 int64_t offset = 0; 225 uint64_t data_offset; 226 uint64_t in_offset = ds->data_fork_offset; 227 uint64_t out_offset; 228 229 type = buff_read_uint32(buffer, offset); 230 /* skip data that is not a valid MISH block (invalid magic or too small) */ 231 if (type != 0x6d697368 || count < 244) { 232 /* assume success for now */ 233 return 0; 234 } 235 236 /* chunk offsets are relative to this sector number */ 237 out_offset = buff_read_uint64(buffer, offset + 8); 238 239 /* location in data fork for (compressed) blob (in bytes) */ 240 data_offset = buff_read_uint64(buffer, offset + 0x18); 241 in_offset += data_offset; 242 243 /* move to begin of chunk entries */ 244 offset += 204; 245 246 chunk_count = (count - 204) / 40; 247 new_size = sizeof(uint64_t) * (s->n_chunks + chunk_count); 248 s->types = g_realloc(s->types, new_size / 2); 249 s->offsets = g_realloc(s->offsets, new_size); 250 s->lengths = g_realloc(s->lengths, new_size); 251 s->sectors = g_realloc(s->sectors, new_size); 252 s->sectorcounts = g_realloc(s->sectorcounts, new_size); 253 254 for (i = s->n_chunks; i < s->n_chunks + chunk_count; i++) { 255 s->types[i] = buff_read_uint32(buffer, offset); 256 if (!dmg_is_known_block_type(s->types[i])) { 257 chunk_count--; 258 i--; 259 offset += 40; 260 continue; 261 } 262 263 /* sector number */ 264 s->sectors[i] = buff_read_uint64(buffer, offset + 8); 265 s->sectors[i] += out_offset; 266 267 /* sector count */ 268 s->sectorcounts[i] = buff_read_uint64(buffer, offset + 0x10); 269 270 /* all-zeroes sector (type UDZE and UDIG) does not need to be 271 * "uncompressed" and can therefore be unbounded. */ 272 if (s->types[i] != UDZE && s->types[i] != UDIG 273 && s->sectorcounts[i] > DMG_SECTORCOUNTS_MAX) { 274 error_report("sector count %" PRIu64 " for chunk %" PRIu32 275 " is larger than max (%u)", 276 s->sectorcounts[i], i, DMG_SECTORCOUNTS_MAX); 277 ret = -EINVAL; 278 goto fail; 279 } 280 281 /* offset in (compressed) data fork */ 282 s->offsets[i] = buff_read_uint64(buffer, offset + 0x18); 283 s->offsets[i] += in_offset; 284 285 /* length in (compressed) data fork */ 286 s->lengths[i] = buff_read_uint64(buffer, offset + 0x20); 287 288 if (s->lengths[i] > DMG_LENGTHS_MAX) { 289 error_report("length %" PRIu64 " for chunk %" PRIu32 290 " is larger than max (%u)", 291 s->lengths[i], i, DMG_LENGTHS_MAX); 292 ret = -EINVAL; 293 goto fail; 294 } 295 296 update_max_chunk_size(s, i, &ds->max_compressed_size, 297 &ds->max_sectors_per_chunk); 298 offset += 40; 299 } 300 s->n_chunks += chunk_count; 301 return 0; 302 303 fail: 304 return ret; 305 } 306 307 static int dmg_read_resource_fork(BlockDriverState *bs, DmgHeaderState *ds, 308 uint64_t info_begin, uint64_t info_length) 309 { 310 BDRVDMGState *s = bs->opaque; 311 int ret; 312 uint32_t count, rsrc_data_offset; 313 uint8_t *buffer = NULL; 314 uint64_t info_end; 315 uint64_t offset; 316 317 /* read offset from begin of resource fork (info_begin) to resource data */ 318 ret = read_uint32(bs, info_begin, &rsrc_data_offset); 319 if (ret < 0) { 320 goto fail; 321 } else if (rsrc_data_offset > info_length) { 322 ret = -EINVAL; 323 goto fail; 324 } 325 326 /* read length of resource data */ 327 ret = read_uint32(bs, info_begin + 8, &count); 328 if (ret < 0) { 329 goto fail; 330 } else if (count == 0 || rsrc_data_offset + count > info_length) { 331 ret = -EINVAL; 332 goto fail; 333 } 334 335 /* begin of resource data (consisting of one or more resources) */ 336 offset = info_begin + rsrc_data_offset; 337 338 /* end of resource data (there is possibly a following resource map 339 * which will be ignored). */ 340 info_end = offset + count; 341 342 /* read offsets (mish blocks) from one or more resources in resource data */ 343 while (offset < info_end) { 344 /* size of following resource */ 345 ret = read_uint32(bs, offset, &count); 346 if (ret < 0) { 347 goto fail; 348 } else if (count == 0 || count > info_end - offset) { 349 ret = -EINVAL; 350 goto fail; 351 } 352 offset += 4; 353 354 buffer = g_realloc(buffer, count); 355 ret = bdrv_pread(bs->file, offset, count, buffer, 0); 356 if (ret < 0) { 357 goto fail; 358 } 359 360 ret = dmg_read_mish_block(s, ds, buffer, count); 361 if (ret < 0) { 362 goto fail; 363 } 364 /* advance offset by size of resource */ 365 offset += count; 366 } 367 ret = 0; 368 369 fail: 370 g_free(buffer); 371 return ret; 372 } 373 374 static int dmg_read_plist_xml(BlockDriverState *bs, DmgHeaderState *ds, 375 uint64_t info_begin, uint64_t info_length) 376 { 377 BDRVDMGState *s = bs->opaque; 378 int ret; 379 uint8_t *buffer = NULL; 380 char *data_begin, *data_end; 381 382 /* Have at least some length to avoid NULL for g_malloc. Attempt to set a 383 * safe upper cap on the data length. A test sample had a XML length of 384 * about 1 MiB. */ 385 if (info_length == 0 || info_length > 16 * 1024 * 1024) { 386 ret = -EINVAL; 387 goto fail; 388 } 389 390 buffer = g_malloc(info_length + 1); 391 buffer[info_length] = '\0'; 392 ret = bdrv_pread(bs->file, info_begin, info_length, buffer, 0); 393 if (ret < 0) { 394 ret = -EINVAL; 395 goto fail; 396 } 397 398 /* look for <data>...</data>. The data is 284 (0x11c) bytes after base64 399 * decode. The actual data element has 431 (0x1af) bytes which includes tabs 400 * and line feeds. */ 401 data_end = (char *)buffer; 402 while ((data_begin = strstr(data_end, "<data>")) != NULL) { 403 guchar *mish; 404 gsize out_len = 0; 405 406 data_begin += 6; 407 data_end = strstr(data_begin, "</data>"); 408 /* malformed XML? */ 409 if (data_end == NULL) { 410 ret = -EINVAL; 411 goto fail; 412 } 413 *data_end++ = '\0'; 414 mish = g_base64_decode(data_begin, &out_len); 415 ret = dmg_read_mish_block(s, ds, mish, (uint32_t)out_len); 416 g_free(mish); 417 if (ret < 0) { 418 goto fail; 419 } 420 } 421 ret = 0; 422 423 fail: 424 g_free(buffer); 425 return ret; 426 } 427 428 static int dmg_open(BlockDriverState *bs, QDict *options, int flags, 429 Error **errp) 430 { 431 BDRVDMGState *s = bs->opaque; 432 DmgHeaderState ds; 433 uint64_t rsrc_fork_offset, rsrc_fork_length; 434 uint64_t plist_xml_offset, plist_xml_length; 435 int64_t offset; 436 int ret; 437 438 ret = bdrv_apply_auto_read_only(bs, NULL, errp); 439 if (ret < 0) { 440 return ret; 441 } 442 443 ret = bdrv_open_file_child(NULL, options, "file", bs, errp); 444 if (ret < 0) { 445 return ret; 446 } 447 448 block_module_load_one("dmg-bz2"); 449 block_module_load_one("dmg-lzfse"); 450 451 s->n_chunks = 0; 452 s->offsets = s->lengths = s->sectors = s->sectorcounts = NULL; 453 /* used by dmg_read_mish_block to keep track of the current I/O position */ 454 ds.data_fork_offset = 0; 455 ds.max_compressed_size = 1; 456 ds.max_sectors_per_chunk = 1; 457 458 /* locate the UDIF trailer */ 459 offset = dmg_find_koly_offset(bs->file, errp); 460 if (offset < 0) { 461 ret = offset; 462 goto fail; 463 } 464 465 /* offset of data fork (DataForkOffset) */ 466 ret = read_uint64(bs, offset + 0x18, &ds.data_fork_offset); 467 if (ret < 0) { 468 goto fail; 469 } else if (ds.data_fork_offset > offset) { 470 ret = -EINVAL; 471 goto fail; 472 } 473 474 /* offset of resource fork (RsrcForkOffset) */ 475 ret = read_uint64(bs, offset + 0x28, &rsrc_fork_offset); 476 if (ret < 0) { 477 goto fail; 478 } 479 ret = read_uint64(bs, offset + 0x30, &rsrc_fork_length); 480 if (ret < 0) { 481 goto fail; 482 } 483 if (rsrc_fork_offset >= offset || 484 rsrc_fork_length > offset - rsrc_fork_offset) { 485 ret = -EINVAL; 486 goto fail; 487 } 488 /* offset of property list (XMLOffset) */ 489 ret = read_uint64(bs, offset + 0xd8, &plist_xml_offset); 490 if (ret < 0) { 491 goto fail; 492 } 493 ret = read_uint64(bs, offset + 0xe0, &plist_xml_length); 494 if (ret < 0) { 495 goto fail; 496 } 497 if (plist_xml_offset >= offset || 498 plist_xml_length > offset - plist_xml_offset) { 499 ret = -EINVAL; 500 goto fail; 501 } 502 ret = read_uint64(bs, offset + 0x1ec, (uint64_t *)&bs->total_sectors); 503 if (ret < 0) { 504 goto fail; 505 } 506 if (bs->total_sectors < 0) { 507 ret = -EINVAL; 508 goto fail; 509 } 510 if (rsrc_fork_length != 0) { 511 ret = dmg_read_resource_fork(bs, &ds, 512 rsrc_fork_offset, rsrc_fork_length); 513 if (ret < 0) { 514 goto fail; 515 } 516 } else if (plist_xml_length != 0) { 517 ret = dmg_read_plist_xml(bs, &ds, plist_xml_offset, plist_xml_length); 518 if (ret < 0) { 519 goto fail; 520 } 521 } else { 522 ret = -EINVAL; 523 goto fail; 524 } 525 526 /* initialize zlib engine */ 527 s->compressed_chunk = qemu_try_blockalign(bs->file->bs, 528 ds.max_compressed_size + 1); 529 s->uncompressed_chunk = qemu_try_blockalign(bs->file->bs, 530 512 * ds.max_sectors_per_chunk); 531 if (s->compressed_chunk == NULL || s->uncompressed_chunk == NULL) { 532 ret = -ENOMEM; 533 goto fail; 534 } 535 536 if (inflateInit(&s->zstream) != Z_OK) { 537 ret = -EINVAL; 538 goto fail; 539 } 540 541 s->current_chunk = s->n_chunks; 542 543 qemu_co_mutex_init(&s->lock); 544 return 0; 545 546 fail: 547 g_free(s->types); 548 g_free(s->offsets); 549 g_free(s->lengths); 550 g_free(s->sectors); 551 g_free(s->sectorcounts); 552 qemu_vfree(s->compressed_chunk); 553 qemu_vfree(s->uncompressed_chunk); 554 return ret; 555 } 556 557 static void dmg_refresh_limits(BlockDriverState *bs, Error **errp) 558 { 559 bs->bl.request_alignment = BDRV_SECTOR_SIZE; /* No sub-sector I/O */ 560 } 561 562 static inline int is_sector_in_chunk(BDRVDMGState *s, 563 uint32_t chunk_num, uint64_t sector_num) 564 { 565 if (chunk_num >= s->n_chunks || s->sectors[chunk_num] > sector_num || 566 s->sectors[chunk_num] + s->sectorcounts[chunk_num] <= sector_num) { 567 return 0; 568 } else { 569 return -1; 570 } 571 } 572 573 static inline uint32_t search_chunk(BDRVDMGState *s, uint64_t sector_num) 574 { 575 /* binary search */ 576 uint32_t chunk1 = 0, chunk2 = s->n_chunks, chunk3; 577 while (chunk1 <= chunk2) { 578 chunk3 = (chunk1 + chunk2) / 2; 579 if (s->sectors[chunk3] > sector_num) { 580 if (chunk3 == 0) { 581 goto err; 582 } 583 chunk2 = chunk3 - 1; 584 } else if (s->sectors[chunk3] + s->sectorcounts[chunk3] > sector_num) { 585 return chunk3; 586 } else { 587 chunk1 = chunk3 + 1; 588 } 589 } 590 err: 591 return s->n_chunks; /* error */ 592 } 593 594 static inline int dmg_read_chunk(BlockDriverState *bs, uint64_t sector_num) 595 { 596 BDRVDMGState *s = bs->opaque; 597 598 if (!is_sector_in_chunk(s, s->current_chunk, sector_num)) { 599 int ret; 600 uint32_t chunk = search_chunk(s, sector_num); 601 602 if (chunk >= s->n_chunks) { 603 return -1; 604 } 605 606 s->current_chunk = s->n_chunks; 607 switch (s->types[chunk]) { /* block entry type */ 608 case UDZO: { /* zlib compressed */ 609 /* we need to buffer, because only the chunk as whole can be 610 * inflated. */ 611 ret = bdrv_pread(bs->file, s->offsets[chunk], s->lengths[chunk], 612 s->compressed_chunk, 0); 613 if (ret < 0) { 614 return -1; 615 } 616 617 s->zstream.next_in = s->compressed_chunk; 618 s->zstream.avail_in = s->lengths[chunk]; 619 s->zstream.next_out = s->uncompressed_chunk; 620 s->zstream.avail_out = 512 * s->sectorcounts[chunk]; 621 ret = inflateReset(&s->zstream); 622 if (ret != Z_OK) { 623 return -1; 624 } 625 ret = inflate(&s->zstream, Z_FINISH); 626 if (ret != Z_STREAM_END || 627 s->zstream.total_out != 512 * s->sectorcounts[chunk]) { 628 return -1; 629 } 630 break; } 631 case UDBZ: /* bzip2 compressed */ 632 if (!dmg_uncompress_bz2) { 633 break; 634 } 635 /* we need to buffer, because only the chunk as whole can be 636 * inflated. */ 637 ret = bdrv_pread(bs->file, s->offsets[chunk], s->lengths[chunk], 638 s->compressed_chunk, 0); 639 if (ret < 0) { 640 return -1; 641 } 642 643 ret = dmg_uncompress_bz2((char *)s->compressed_chunk, 644 (unsigned int) s->lengths[chunk], 645 (char *)s->uncompressed_chunk, 646 (unsigned int) 647 (512 * s->sectorcounts[chunk])); 648 if (ret < 0) { 649 return ret; 650 } 651 break; 652 case ULFO: 653 if (!dmg_uncompress_lzfse) { 654 break; 655 } 656 /* we need to buffer, because only the chunk as whole can be 657 * inflated. */ 658 ret = bdrv_pread(bs->file, s->offsets[chunk], s->lengths[chunk], 659 s->compressed_chunk, 0); 660 if (ret < 0) { 661 return -1; 662 } 663 664 ret = dmg_uncompress_lzfse((char *)s->compressed_chunk, 665 (unsigned int) s->lengths[chunk], 666 (char *)s->uncompressed_chunk, 667 (unsigned int) 668 (512 * s->sectorcounts[chunk])); 669 if (ret < 0) { 670 return ret; 671 } 672 break; 673 case UDRW: /* copy */ 674 ret = bdrv_pread(bs->file, s->offsets[chunk], s->lengths[chunk], 675 s->uncompressed_chunk, 0); 676 if (ret < 0) { 677 return -1; 678 } 679 break; 680 case UDZE: /* zeros */ 681 case UDIG: /* ignore */ 682 /* see dmg_read, it is treated specially. No buffer needs to be 683 * pre-filled, the zeroes can be set directly. */ 684 break; 685 } 686 s->current_chunk = chunk; 687 } 688 return 0; 689 } 690 691 static int coroutine_fn 692 dmg_co_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes, 693 QEMUIOVector *qiov, BdrvRequestFlags flags) 694 { 695 BDRVDMGState *s = bs->opaque; 696 uint64_t sector_num = offset >> BDRV_SECTOR_BITS; 697 int nb_sectors = bytes >> BDRV_SECTOR_BITS; 698 int ret, i; 699 700 assert(QEMU_IS_ALIGNED(offset, BDRV_SECTOR_SIZE)); 701 assert(QEMU_IS_ALIGNED(bytes, BDRV_SECTOR_SIZE)); 702 703 qemu_co_mutex_lock(&s->lock); 704 705 for (i = 0; i < nb_sectors; i++) { 706 uint32_t sector_offset_in_chunk; 707 void *data; 708 709 if (dmg_read_chunk(bs, sector_num + i) != 0) { 710 ret = -EIO; 711 goto fail; 712 } 713 /* Special case: current chunk is all zeroes. Do not perform a memcpy as 714 * s->uncompressed_chunk may be too small to cover the large all-zeroes 715 * section. dmg_read_chunk is called to find s->current_chunk */ 716 if (s->types[s->current_chunk] == UDZE 717 || s->types[s->current_chunk] == UDIG) { /* all zeroes block entry */ 718 qemu_iovec_memset(qiov, i * 512, 0, 512); 719 continue; 720 } 721 sector_offset_in_chunk = sector_num + i - s->sectors[s->current_chunk]; 722 data = s->uncompressed_chunk + sector_offset_in_chunk * 512; 723 qemu_iovec_from_buf(qiov, i * 512, data, 512); 724 } 725 726 ret = 0; 727 fail: 728 qemu_co_mutex_unlock(&s->lock); 729 return ret; 730 } 731 732 static void dmg_close(BlockDriverState *bs) 733 { 734 BDRVDMGState *s = bs->opaque; 735 736 g_free(s->types); 737 g_free(s->offsets); 738 g_free(s->lengths); 739 g_free(s->sectors); 740 g_free(s->sectorcounts); 741 qemu_vfree(s->compressed_chunk); 742 qemu_vfree(s->uncompressed_chunk); 743 744 inflateEnd(&s->zstream); 745 } 746 747 static BlockDriver bdrv_dmg = { 748 .format_name = "dmg", 749 .instance_size = sizeof(BDRVDMGState), 750 .bdrv_probe = dmg_probe, 751 .bdrv_open = dmg_open, 752 .bdrv_refresh_limits = dmg_refresh_limits, 753 .bdrv_child_perm = bdrv_default_perms, 754 .bdrv_co_preadv = dmg_co_preadv, 755 .bdrv_close = dmg_close, 756 .is_format = true, 757 }; 758 759 static void bdrv_dmg_init(void) 760 { 761 bdrv_register(&bdrv_dmg); 762 } 763 764 block_init(bdrv_dmg_init); 765