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 "dmg.h" 31 32 int (*dmg_uncompress_bz2)(char *next_in, unsigned int avail_in, 33 char *next_out, unsigned int avail_out); 34 35 int (*dmg_uncompress_lzfse)(char *next_in, unsigned int avail_in, 36 char *next_out, unsigned int avail_out); 37 38 enum { 39 /* Limit chunk sizes to prevent unreasonable amounts of memory being used 40 * or truncating when converting to 32-bit types 41 */ 42 DMG_LENGTHS_MAX = 64 * 1024 * 1024, /* 64 MB */ 43 DMG_SECTORCOUNTS_MAX = DMG_LENGTHS_MAX / 512, 44 }; 45 46 enum { 47 /* DMG Block Type */ 48 UDZE = 0, /* Zeroes */ 49 UDRW, /* RAW type */ 50 UDIG, /* Ignore */ 51 UDCO = 0x80000004, 52 UDZO, 53 UDBZ, 54 ULFO, 55 UDCM = 0x7ffffffe, /* Comments */ 56 UDLE = 0xffffffff /* Last Entry */ 57 }; 58 59 static int dmg_probe(const uint8_t *buf, int buf_size, const char *filename) 60 { 61 int len; 62 63 if (!filename) { 64 return 0; 65 } 66 67 len = strlen(filename); 68 if (len > 4 && !strcmp(filename + len - 4, ".dmg")) { 69 return 2; 70 } 71 return 0; 72 } 73 74 static int read_uint64(BlockDriverState *bs, int64_t offset, uint64_t *result) 75 { 76 uint64_t buffer; 77 int ret; 78 79 ret = bdrv_pread(bs->file, offset, &buffer, 8); 80 if (ret < 0) { 81 return ret; 82 } 83 84 *result = be64_to_cpu(buffer); 85 return 0; 86 } 87 88 static int read_uint32(BlockDriverState *bs, int64_t offset, uint32_t *result) 89 { 90 uint32_t buffer; 91 int ret; 92 93 ret = bdrv_pread(bs->file, offset, &buffer, 4); 94 if (ret < 0) { 95 return ret; 96 } 97 98 *result = be32_to_cpu(buffer); 99 return 0; 100 } 101 102 static inline uint64_t buff_read_uint64(const uint8_t *buffer, int64_t offset) 103 { 104 return be64_to_cpu(*(uint64_t *)&buffer[offset]); 105 } 106 107 static inline uint32_t buff_read_uint32(const uint8_t *buffer, int64_t offset) 108 { 109 return be32_to_cpu(*(uint32_t *)&buffer[offset]); 110 } 111 112 /* Increase max chunk sizes, if necessary. This function is used to calculate 113 * the buffer sizes needed for compressed/uncompressed chunk I/O. 114 */ 115 static void update_max_chunk_size(BDRVDMGState *s, uint32_t chunk, 116 uint32_t *max_compressed_size, 117 uint32_t *max_sectors_per_chunk) 118 { 119 uint32_t compressed_size = 0; 120 uint32_t uncompressed_sectors = 0; 121 122 switch (s->types[chunk]) { 123 case UDZO: /* zlib compressed */ 124 case UDBZ: /* bzip2 compressed */ 125 case ULFO: /* lzfse compressed */ 126 compressed_size = s->lengths[chunk]; 127 uncompressed_sectors = s->sectorcounts[chunk]; 128 break; 129 case UDRW: /* copy */ 130 uncompressed_sectors = DIV_ROUND_UP(s->lengths[chunk], 512); 131 break; 132 case UDZE: /* zero */ 133 case UDIG: /* ignore */ 134 /* as the all-zeroes block may be large, it is treated specially: the 135 * sector is not copied from a large buffer, a simple memset is used 136 * instead. Therefore uncompressed_sectors does not need to be set. */ 137 break; 138 } 139 140 if (compressed_size > *max_compressed_size) { 141 *max_compressed_size = compressed_size; 142 } 143 if (uncompressed_sectors > *max_sectors_per_chunk) { 144 *max_sectors_per_chunk = uncompressed_sectors; 145 } 146 } 147 148 static int64_t dmg_find_koly_offset(BdrvChild *file, Error **errp) 149 { 150 BlockDriverState *file_bs = file->bs; 151 int64_t length; 152 int64_t offset = 0; 153 uint8_t buffer[515]; 154 int i, ret; 155 156 /* bdrv_getlength returns a multiple of block size (512), rounded up. Since 157 * dmg images can have odd sizes, try to look for the "koly" magic which 158 * marks the begin of the UDIF trailer (512 bytes). This magic can be found 159 * in the last 511 bytes of the second-last sector or the first 4 bytes of 160 * the last sector (search space: 515 bytes) */ 161 length = bdrv_getlength(file_bs); 162 if (length < 0) { 163 error_setg_errno(errp, -length, 164 "Failed to get file size while reading UDIF trailer"); 165 return length; 166 } else if (length < 512) { 167 error_setg(errp, "dmg file must be at least 512 bytes long"); 168 return -EINVAL; 169 } 170 if (length > 511 + 512) { 171 offset = length - 511 - 512; 172 } 173 length = length < 515 ? length : 515; 174 ret = bdrv_pread(file, offset, buffer, length); 175 if (ret < 0) { 176 error_setg_errno(errp, -ret, "Failed while reading UDIF trailer"); 177 return ret; 178 } 179 for (i = 0; i < length - 3; i++) { 180 if (buffer[i] == 'k' && buffer[i+1] == 'o' && 181 buffer[i+2] == 'l' && buffer[i+3] == 'y') { 182 return offset + i; 183 } 184 } 185 error_setg(errp, "Could not locate UDIF trailer in dmg file"); 186 return -EINVAL; 187 } 188 189 /* used when building the sector table */ 190 typedef struct DmgHeaderState { 191 /* used internally by dmg_read_mish_block to remember offsets of blocks 192 * across calls */ 193 uint64_t data_fork_offset; 194 /* exported for dmg_open */ 195 uint32_t max_compressed_size; 196 uint32_t max_sectors_per_chunk; 197 } DmgHeaderState; 198 199 static bool dmg_is_known_block_type(uint32_t entry_type) 200 { 201 switch (entry_type) { 202 case UDZE: /* zeros */ 203 case UDRW: /* uncompressed */ 204 case UDIG: /* ignore */ 205 case UDZO: /* zlib */ 206 return true; 207 case UDBZ: /* bzip2 */ 208 return !!dmg_uncompress_bz2; 209 case ULFO: /* lzfse */ 210 return !!dmg_uncompress_lzfse; 211 default: 212 return false; 213 } 214 } 215 216 static int dmg_read_mish_block(BDRVDMGState *s, DmgHeaderState *ds, 217 uint8_t *buffer, uint32_t count) 218 { 219 uint32_t type, i; 220 int ret; 221 size_t new_size; 222 uint32_t chunk_count; 223 int64_t offset = 0; 224 uint64_t data_offset; 225 uint64_t in_offset = ds->data_fork_offset; 226 uint64_t out_offset; 227 228 type = buff_read_uint32(buffer, offset); 229 /* skip data that is not a valid MISH block (invalid magic or too small) */ 230 if (type != 0x6d697368 || count < 244) { 231 /* assume success for now */ 232 return 0; 233 } 234 235 /* chunk offsets are relative to this sector number */ 236 out_offset = buff_read_uint64(buffer, offset + 8); 237 238 /* location in data fork for (compressed) blob (in bytes) */ 239 data_offset = buff_read_uint64(buffer, offset + 0x18); 240 in_offset += data_offset; 241 242 /* move to begin of chunk entries */ 243 offset += 204; 244 245 chunk_count = (count - 204) / 40; 246 new_size = sizeof(uint64_t) * (s->n_chunks + chunk_count); 247 s->types = g_realloc(s->types, new_size / 2); 248 s->offsets = g_realloc(s->offsets, new_size); 249 s->lengths = g_realloc(s->lengths, new_size); 250 s->sectors = g_realloc(s->sectors, new_size); 251 s->sectorcounts = g_realloc(s->sectorcounts, new_size); 252 253 for (i = s->n_chunks; i < s->n_chunks + chunk_count; i++) { 254 s->types[i] = buff_read_uint32(buffer, offset); 255 if (!dmg_is_known_block_type(s->types[i])) { 256 chunk_count--; 257 i--; 258 offset += 40; 259 continue; 260 } 261 262 /* sector number */ 263 s->sectors[i] = buff_read_uint64(buffer, offset + 8); 264 s->sectors[i] += out_offset; 265 266 /* sector count */ 267 s->sectorcounts[i] = buff_read_uint64(buffer, offset + 0x10); 268 269 /* all-zeroes sector (type UDZE and UDIG) does not need to be 270 * "uncompressed" and can therefore be unbounded. */ 271 if (s->types[i] != UDZE && s->types[i] != UDIG 272 && s->sectorcounts[i] > DMG_SECTORCOUNTS_MAX) { 273 error_report("sector count %" PRIu64 " for chunk %" PRIu32 274 " is larger than max (%u)", 275 s->sectorcounts[i], i, DMG_SECTORCOUNTS_MAX); 276 ret = -EINVAL; 277 goto fail; 278 } 279 280 /* offset in (compressed) data fork */ 281 s->offsets[i] = buff_read_uint64(buffer, offset + 0x18); 282 s->offsets[i] += in_offset; 283 284 /* length in (compressed) data fork */ 285 s->lengths[i] = buff_read_uint64(buffer, offset + 0x20); 286 287 if (s->lengths[i] > DMG_LENGTHS_MAX) { 288 error_report("length %" PRIu64 " for chunk %" PRIu32 289 " is larger than max (%u)", 290 s->lengths[i], i, DMG_LENGTHS_MAX); 291 ret = -EINVAL; 292 goto fail; 293 } 294 295 update_max_chunk_size(s, i, &ds->max_compressed_size, 296 &ds->max_sectors_per_chunk); 297 offset += 40; 298 } 299 s->n_chunks += chunk_count; 300 return 0; 301 302 fail: 303 return ret; 304 } 305 306 static int dmg_read_resource_fork(BlockDriverState *bs, DmgHeaderState *ds, 307 uint64_t info_begin, uint64_t info_length) 308 { 309 BDRVDMGState *s = bs->opaque; 310 int ret; 311 uint32_t count, rsrc_data_offset; 312 uint8_t *buffer = NULL; 313 uint64_t info_end; 314 uint64_t offset; 315 316 /* read offset from begin of resource fork (info_begin) to resource data */ 317 ret = read_uint32(bs, info_begin, &rsrc_data_offset); 318 if (ret < 0) { 319 goto fail; 320 } else if (rsrc_data_offset > info_length) { 321 ret = -EINVAL; 322 goto fail; 323 } 324 325 /* read length of resource data */ 326 ret = read_uint32(bs, info_begin + 8, &count); 327 if (ret < 0) { 328 goto fail; 329 } else if (count == 0 || rsrc_data_offset + count > info_length) { 330 ret = -EINVAL; 331 goto fail; 332 } 333 334 /* begin of resource data (consisting of one or more resources) */ 335 offset = info_begin + rsrc_data_offset; 336 337 /* end of resource data (there is possibly a following resource map 338 * which will be ignored). */ 339 info_end = offset + count; 340 341 /* read offsets (mish blocks) from one or more resources in resource data */ 342 while (offset < info_end) { 343 /* size of following resource */ 344 ret = read_uint32(bs, offset, &count); 345 if (ret < 0) { 346 goto fail; 347 } else if (count == 0 || count > info_end - offset) { 348 ret = -EINVAL; 349 goto fail; 350 } 351 offset += 4; 352 353 buffer = g_realloc(buffer, count); 354 ret = bdrv_pread(bs->file, offset, buffer, count); 355 if (ret < 0) { 356 goto fail; 357 } 358 359 ret = dmg_read_mish_block(s, ds, buffer, count); 360 if (ret < 0) { 361 goto fail; 362 } 363 /* advance offset by size of resource */ 364 offset += count; 365 } 366 ret = 0; 367 368 fail: 369 g_free(buffer); 370 return ret; 371 } 372 373 static int dmg_read_plist_xml(BlockDriverState *bs, DmgHeaderState *ds, 374 uint64_t info_begin, uint64_t info_length) 375 { 376 BDRVDMGState *s = bs->opaque; 377 int ret; 378 uint8_t *buffer = NULL; 379 char *data_begin, *data_end; 380 381 /* Have at least some length to avoid NULL for g_malloc. Attempt to set a 382 * safe upper cap on the data length. A test sample had a XML length of 383 * about 1 MiB. */ 384 if (info_length == 0 || info_length > 16 * 1024 * 1024) { 385 ret = -EINVAL; 386 goto fail; 387 } 388 389 buffer = g_malloc(info_length + 1); 390 buffer[info_length] = '\0'; 391 ret = bdrv_pread(bs->file, info_begin, buffer, info_length); 392 if (ret != info_length) { 393 ret = -EINVAL; 394 goto fail; 395 } 396 397 /* look for <data>...</data>. The data is 284 (0x11c) bytes after base64 398 * decode. The actual data element has 431 (0x1af) bytes which includes tabs 399 * and line feeds. */ 400 data_end = (char *)buffer; 401 while ((data_begin = strstr(data_end, "<data>")) != NULL) { 402 guchar *mish; 403 gsize out_len = 0; 404 405 data_begin += 6; 406 data_end = strstr(data_begin, "</data>"); 407 /* malformed XML? */ 408 if (data_end == NULL) { 409 ret = -EINVAL; 410 goto fail; 411 } 412 *data_end++ = '\0'; 413 mish = g_base64_decode(data_begin, &out_len); 414 ret = dmg_read_mish_block(s, ds, mish, (uint32_t)out_len); 415 g_free(mish); 416 if (ret < 0) { 417 goto fail; 418 } 419 } 420 ret = 0; 421 422 fail: 423 g_free(buffer); 424 return ret; 425 } 426 427 static int dmg_open(BlockDriverState *bs, QDict *options, int flags, 428 Error **errp) 429 { 430 BDRVDMGState *s = bs->opaque; 431 DmgHeaderState ds; 432 uint64_t rsrc_fork_offset, rsrc_fork_length; 433 uint64_t plist_xml_offset, plist_xml_length; 434 int64_t offset; 435 int ret; 436 437 ret = bdrv_apply_auto_read_only(bs, NULL, errp); 438 if (ret < 0) { 439 return ret; 440 } 441 442 bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds, 443 BDRV_CHILD_IMAGE, false, errp); 444 if (!bs->file) { 445 return -EINVAL; 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], 612 s->compressed_chunk, s->lengths[chunk]); 613 if (ret != s->lengths[chunk]) { 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], 638 s->compressed_chunk, s->lengths[chunk]); 639 if (ret != s->lengths[chunk]) { 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], 659 s->compressed_chunk, s->lengths[chunk]); 660 if (ret != s->lengths[chunk]) { 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], 675 s->uncompressed_chunk, s->lengths[chunk]); 676 if (ret != s->lengths[chunk]) { 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, uint64_t offset, uint64_t bytes, 693 QEMUIOVector *qiov, int 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