1 // 2 // Copyright (C) 2015 The Android Open Source Project 3 // 4 // Licensed under the Apache License, Version 2.0 (the "License"); 5 // you may not use this file except in compliance with the License. 6 // You may obtain a copy of the License at 7 // 8 // http://www.apache.org/licenses/LICENSE-2.0 9 // 10 // Unless required by applicable law or agreed to in writing, software 11 // distributed under the License is distributed on an "AS IS" BASIS, 12 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 // See the License for the specific language governing permissions and 14 // limitations under the License. 15 // 16 17 #include "update_engine/payload_generator/delta_diff_utils.h" 18 19 #include <algorithm> 20 #include <map> 21 22 #include <base/files/file_util.h> 23 #include <base/format_macros.h> 24 #include <base/strings/stringprintf.h> 25 26 #include "update_engine/common/hash_calculator.h" 27 #include "update_engine/common/subprocess.h" 28 #include "update_engine/common/utils.h" 29 #include "update_engine/payload_generator/block_mapping.h" 30 #include "update_engine/payload_generator/bzip.h" 31 #include "update_engine/payload_generator/delta_diff_generator.h" 32 #include "update_engine/payload_generator/extent_ranges.h" 33 #include "update_engine/payload_generator/extent_utils.h" 34 #include "update_engine/payload_generator/xz.h" 35 36 using std::map; 37 using std::string; 38 using std::vector; 39 40 namespace chromeos_update_engine { 41 namespace { 42 43 const char* const kBsdiffPath = "bsdiff"; 44 const char* const kImgdiffPath = "imgdiff"; 45 46 // The maximum destination size allowed for bsdiff. In general, bsdiff should 47 // work for arbitrary big files, but the payload generation and payload 48 // application requires a significant amount of RAM. We put a hard-limit of 49 // 200 MiB that should not affect any released board, but will limit the 50 // Chrome binary in ASan builders. 51 const uint64_t kMaxBsdiffDestinationSize = 200 * 1024 * 1024; // bytes 52 53 // The maximum destination size allowed for imgdiff. In general, imgdiff should 54 // work for arbitrary big files, but the payload application is quite memory 55 // intensive, so we limit these operations to 50 MiB. 56 const uint64_t kMaxImgdiffDestinationSize = 50 * 1024 * 1024; // bytes 57 58 // Process a range of blocks from |range_start| to |range_end| in the extent at 59 // position |*idx_p| of |extents|. If |do_remove| is true, this range will be 60 // removed, which may cause the extent to be trimmed, split or removed entirely. 61 // The value of |*idx_p| is updated to point to the next extent to be processed. 62 // Returns true iff the next extent to process is a new or updated one. 63 bool ProcessExtentBlockRange(vector<Extent>* extents, size_t* idx_p, 64 const bool do_remove, uint64_t range_start, 65 uint64_t range_end) { 66 size_t idx = *idx_p; 67 uint64_t start_block = (*extents)[idx].start_block(); 68 uint64_t num_blocks = (*extents)[idx].num_blocks(); 69 uint64_t range_size = range_end - range_start; 70 71 if (do_remove) { 72 if (range_size == num_blocks) { 73 // Remove the entire extent. 74 extents->erase(extents->begin() + idx); 75 } else if (range_end == num_blocks) { 76 // Trim the end of the extent. 77 (*extents)[idx].set_num_blocks(num_blocks - range_size); 78 idx++; 79 } else if (range_start == 0) { 80 // Trim the head of the extent. 81 (*extents)[idx].set_start_block(start_block + range_size); 82 (*extents)[idx].set_num_blocks(num_blocks - range_size); 83 } else { 84 // Trim the middle, splitting the remainder into two parts. 85 (*extents)[idx].set_num_blocks(range_start); 86 Extent e; 87 e.set_start_block(start_block + range_end); 88 e.set_num_blocks(num_blocks - range_end); 89 idx++; 90 extents->insert(extents->begin() + idx, e); 91 } 92 } else if (range_end == num_blocks) { 93 // Done with this extent. 94 idx++; 95 } else { 96 return false; 97 } 98 99 *idx_p = idx; 100 return true; 101 } 102 103 // Remove identical corresponding block ranges in |src_extents| and 104 // |dst_extents|. Used for preventing moving of blocks onto themselves during 105 // MOVE operations. The value of |total_bytes| indicates the actual length of 106 // content; this may be slightly less than the total size of blocks, in which 107 // case the last block is only partly occupied with data. Returns the total 108 // number of bytes removed. 109 size_t RemoveIdenticalBlockRanges(vector<Extent>* src_extents, 110 vector<Extent>* dst_extents, 111 const size_t total_bytes) { 112 size_t src_idx = 0; 113 size_t dst_idx = 0; 114 uint64_t src_offset = 0, dst_offset = 0; 115 bool new_src = true, new_dst = true; 116 size_t removed_bytes = 0, nonfull_block_bytes; 117 bool do_remove = false; 118 while (src_idx < src_extents->size() && dst_idx < dst_extents->size()) { 119 if (new_src) { 120 src_offset = 0; 121 new_src = false; 122 } 123 if (new_dst) { 124 dst_offset = 0; 125 new_dst = false; 126 } 127 128 do_remove = ((*src_extents)[src_idx].start_block() + src_offset == 129 (*dst_extents)[dst_idx].start_block() + dst_offset); 130 131 uint64_t src_num_blocks = (*src_extents)[src_idx].num_blocks(); 132 uint64_t dst_num_blocks = (*dst_extents)[dst_idx].num_blocks(); 133 uint64_t min_num_blocks = std::min(src_num_blocks - src_offset, 134 dst_num_blocks - dst_offset); 135 uint64_t prev_src_offset = src_offset; 136 uint64_t prev_dst_offset = dst_offset; 137 src_offset += min_num_blocks; 138 dst_offset += min_num_blocks; 139 140 new_src = ProcessExtentBlockRange(src_extents, &src_idx, do_remove, 141 prev_src_offset, src_offset); 142 new_dst = ProcessExtentBlockRange(dst_extents, &dst_idx, do_remove, 143 prev_dst_offset, dst_offset); 144 if (do_remove) 145 removed_bytes += min_num_blocks * kBlockSize; 146 } 147 148 // If we removed the last block and this block is only partly used by file 149 // content, deduct the unused portion from the total removed byte count. 150 if (do_remove && (nonfull_block_bytes = total_bytes % kBlockSize)) 151 removed_bytes -= kBlockSize - nonfull_block_bytes; 152 153 return removed_bytes; 154 } 155 156 // Returns true if the given blob |data| contains gzip header magic. 157 bool ContainsGZip(const brillo::Blob& data) { 158 const uint8_t kGZipMagic[] = {0x1f, 0x8b, 0x08, 0x00}; 159 return std::search(data.begin(), 160 data.end(), 161 std::begin(kGZipMagic), 162 std::end(kGZipMagic)) != data.end(); 163 } 164 165 } // namespace 166 167 namespace diff_utils { 168 169 bool DeltaReadPartition(vector<AnnotatedOperation>* aops, 170 const PartitionConfig& old_part, 171 const PartitionConfig& new_part, 172 ssize_t hard_chunk_blocks, 173 size_t soft_chunk_blocks, 174 const PayloadVersion& version, 175 BlobFileWriter* blob_file) { 176 ExtentRanges old_visited_blocks; 177 ExtentRanges new_visited_blocks; 178 179 TEST_AND_RETURN_FALSE(DeltaMovedAndZeroBlocks( 180 aops, 181 old_part.path, 182 new_part.path, 183 old_part.fs_interface ? old_part.fs_interface->GetBlockCount() : 0, 184 new_part.fs_interface->GetBlockCount(), 185 soft_chunk_blocks, 186 version, 187 blob_file, 188 &old_visited_blocks, 189 &new_visited_blocks)); 190 191 map<string, vector<Extent>> old_files_map; 192 if (old_part.fs_interface) { 193 vector<FilesystemInterface::File> old_files; 194 old_part.fs_interface->GetFiles(&old_files); 195 for (const FilesystemInterface::File& file : old_files) 196 old_files_map[file.name] = file.extents; 197 } 198 199 TEST_AND_RETURN_FALSE(new_part.fs_interface); 200 vector<FilesystemInterface::File> new_files; 201 new_part.fs_interface->GetFiles(&new_files); 202 203 // The processing is very straightforward here, we generate operations for 204 // every file (and pseudo-file such as the metadata) in the new filesystem 205 // based on the file with the same name in the old filesystem, if any. 206 // Files with overlapping data blocks (like hardlinks or filesystems with tail 207 // packing or compression where the blocks store more than one file) are only 208 // generated once in the new image, but are also used only once from the old 209 // image due to some simplifications (see below). 210 for (const FilesystemInterface::File& new_file : new_files) { 211 // Ignore the files in the new filesystem without blocks. Symlinks with 212 // data blocks (for example, symlinks bigger than 60 bytes in ext2) are 213 // handled as normal files. We also ignore blocks that were already 214 // processed by a previous file. 215 vector<Extent> new_file_extents = FilterExtentRanges( 216 new_file.extents, new_visited_blocks); 217 new_visited_blocks.AddExtents(new_file_extents); 218 219 if (new_file_extents.empty()) 220 continue; 221 222 LOG(INFO) << "Encoding file " << new_file.name << " (" 223 << BlocksInExtents(new_file_extents) << " blocks)"; 224 225 // We can't visit each dst image inode more than once, as that would 226 // duplicate work. Here, we avoid visiting each source image inode 227 // more than once. Technically, we could have multiple operations 228 // that read the same blocks from the source image for diffing, but 229 // we choose not to avoid complexity. Eventually we will move away 230 // from using a graph/cycle detection/etc to generate diffs, and at that 231 // time, it will be easy (non-complex) to have many operations read 232 // from the same source blocks. At that time, this code can die. -adlr 233 vector<Extent> old_file_extents = FilterExtentRanges( 234 old_files_map[new_file.name], old_visited_blocks); 235 old_visited_blocks.AddExtents(old_file_extents); 236 237 TEST_AND_RETURN_FALSE(DeltaReadFile(aops, 238 old_part.path, 239 new_part.path, 240 old_file_extents, 241 new_file_extents, 242 new_file.name, // operation name 243 hard_chunk_blocks, 244 version, 245 blob_file)); 246 } 247 // Process all the blocks not included in any file. We provided all the unused 248 // blocks in the old partition as available data. 249 vector<Extent> new_unvisited = { 250 ExtentForRange(0, new_part.size / kBlockSize)}; 251 new_unvisited = FilterExtentRanges(new_unvisited, new_visited_blocks); 252 if (new_unvisited.empty()) 253 return true; 254 255 vector<Extent> old_unvisited; 256 if (old_part.fs_interface) { 257 old_unvisited.push_back(ExtentForRange(0, old_part.size / kBlockSize)); 258 old_unvisited = FilterExtentRanges(old_unvisited, old_visited_blocks); 259 } 260 261 LOG(INFO) << "Scanning " << BlocksInExtents(new_unvisited) 262 << " unwritten blocks using chunk size of " 263 << soft_chunk_blocks << " blocks."; 264 // We use the soft_chunk_blocks limit for the <non-file-data> as we don't 265 // really know the structure of this data and we should not expect it to have 266 // redundancy between partitions. 267 TEST_AND_RETURN_FALSE(DeltaReadFile(aops, 268 old_part.path, 269 new_part.path, 270 old_unvisited, 271 new_unvisited, 272 "<non-file-data>", // operation name 273 soft_chunk_blocks, 274 version, 275 blob_file)); 276 277 return true; 278 } 279 280 bool DeltaMovedAndZeroBlocks(vector<AnnotatedOperation>* aops, 281 const string& old_part, 282 const string& new_part, 283 size_t old_num_blocks, 284 size_t new_num_blocks, 285 ssize_t chunk_blocks, 286 const PayloadVersion& version, 287 BlobFileWriter* blob_file, 288 ExtentRanges* old_visited_blocks, 289 ExtentRanges* new_visited_blocks) { 290 vector<BlockMapping::BlockId> old_block_ids; 291 vector<BlockMapping::BlockId> new_block_ids; 292 TEST_AND_RETURN_FALSE(MapPartitionBlocks(old_part, 293 new_part, 294 old_num_blocks * kBlockSize, 295 new_num_blocks * kBlockSize, 296 kBlockSize, 297 &old_block_ids, 298 &new_block_ids)); 299 300 // If the update is inplace, we map all the blocks that didn't move, 301 // regardless of the contents since they are already copied and no operation 302 // is required. 303 if (version.InplaceUpdate()) { 304 uint64_t num_blocks = std::min(old_num_blocks, new_num_blocks); 305 for (uint64_t block = 0; block < num_blocks; block++) { 306 if (old_block_ids[block] == new_block_ids[block] && 307 !old_visited_blocks->ContainsBlock(block) && 308 !new_visited_blocks->ContainsBlock(block)) { 309 old_visited_blocks->AddBlock(block); 310 new_visited_blocks->AddBlock(block); 311 } 312 } 313 } 314 315 // A mapping from the block_id to the list of block numbers with that block id 316 // in the old partition. This is used to lookup where in the old partition 317 // is a block from the new partition. 318 map<BlockMapping::BlockId, vector<uint64_t>> old_blocks_map; 319 320 for (uint64_t block = old_num_blocks; block-- > 0; ) { 321 if (old_block_ids[block] != 0 && !old_visited_blocks->ContainsBlock(block)) 322 old_blocks_map[old_block_ids[block]].push_back(block); 323 } 324 325 // The collection of blocks in the new partition with just zeros. This is a 326 // common case for free-space that's also problematic for bsdiff, so we want 327 // to optimize it using REPLACE_BZ operations. The blob for a REPLACE_BZ of 328 // just zeros is so small that it doesn't make sense to spend the I/O reading 329 // zeros from the old partition. 330 vector<Extent> new_zeros; 331 332 vector<Extent> old_identical_blocks; 333 vector<Extent> new_identical_blocks; 334 335 for (uint64_t block = 0; block < new_num_blocks; block++) { 336 // Only produce operations for blocks that were not yet visited. 337 if (new_visited_blocks->ContainsBlock(block)) 338 continue; 339 if (new_block_ids[block] == 0) { 340 AppendBlockToExtents(&new_zeros, block); 341 continue; 342 } 343 344 auto old_blocks_map_it = old_blocks_map.find(new_block_ids[block]); 345 // Check if the block exists in the old partition at all. 346 if (old_blocks_map_it == old_blocks_map.end() || 347 old_blocks_map_it->second.empty()) 348 continue; 349 350 AppendBlockToExtents(&old_identical_blocks, 351 old_blocks_map_it->second.back()); 352 AppendBlockToExtents(&new_identical_blocks, block); 353 // We can't reuse source blocks in minor version 1 because the cycle 354 // breaking algorithm used in the in-place update doesn't support that. 355 if (version.InplaceUpdate()) 356 old_blocks_map_it->second.pop_back(); 357 } 358 359 // Produce operations for the zero blocks split per output extent. 360 // TODO(deymo): Produce ZERO operations instead of calling DeltaReadFile(). 361 size_t num_ops = aops->size(); 362 new_visited_blocks->AddExtents(new_zeros); 363 for (Extent extent : new_zeros) { 364 TEST_AND_RETURN_FALSE(DeltaReadFile(aops, 365 "", 366 new_part, 367 vector<Extent>(), // old_extents 368 vector<Extent>{extent}, // new_extents 369 "<zeros>", 370 chunk_blocks, 371 version, 372 blob_file)); 373 } 374 LOG(INFO) << "Produced " << (aops->size() - num_ops) << " operations for " 375 << BlocksInExtents(new_zeros) << " zeroed blocks"; 376 377 // Produce MOVE/SOURCE_COPY operations for the moved blocks. 378 num_ops = aops->size(); 379 if (chunk_blocks == -1) 380 chunk_blocks = new_num_blocks; 381 uint64_t used_blocks = 0; 382 old_visited_blocks->AddExtents(old_identical_blocks); 383 new_visited_blocks->AddExtents(new_identical_blocks); 384 for (Extent extent : new_identical_blocks) { 385 // We split the operation at the extent boundary or when bigger than 386 // chunk_blocks. 387 for (uint64_t op_block_offset = 0; op_block_offset < extent.num_blocks(); 388 op_block_offset += chunk_blocks) { 389 aops->emplace_back(); 390 AnnotatedOperation* aop = &aops->back(); 391 aop->name = "<identical-blocks>"; 392 aop->op.set_type(version.OperationAllowed(InstallOperation::SOURCE_COPY) 393 ? InstallOperation::SOURCE_COPY 394 : InstallOperation::MOVE); 395 396 uint64_t chunk_num_blocks = 397 std::min(extent.num_blocks() - op_block_offset, 398 static_cast<uint64_t>(chunk_blocks)); 399 400 // The current operation represents the move/copy operation for the 401 // sublist starting at |used_blocks| of length |chunk_num_blocks| where 402 // the src and dst are from |old_identical_blocks| and 403 // |new_identical_blocks| respectively. 404 StoreExtents( 405 ExtentsSublist(old_identical_blocks, used_blocks, chunk_num_blocks), 406 aop->op.mutable_src_extents()); 407 408 Extent* op_dst_extent = aop->op.add_dst_extents(); 409 op_dst_extent->set_start_block(extent.start_block() + op_block_offset); 410 op_dst_extent->set_num_blocks(chunk_num_blocks); 411 CHECK( 412 vector<Extent>{*op_dst_extent} == // NOLINT(whitespace/braces) 413 ExtentsSublist(new_identical_blocks, used_blocks, chunk_num_blocks)); 414 415 used_blocks += chunk_num_blocks; 416 } 417 } 418 LOG(INFO) << "Produced " << (aops->size() - num_ops) << " operations for " 419 << used_blocks << " identical blocks moved"; 420 421 return true; 422 } 423 424 bool DeltaReadFile(vector<AnnotatedOperation>* aops, 425 const string& old_part, 426 const string& new_part, 427 const vector<Extent>& old_extents, 428 const vector<Extent>& new_extents, 429 const string& name, 430 ssize_t chunk_blocks, 431 const PayloadVersion& version, 432 BlobFileWriter* blob_file) { 433 brillo::Blob data; 434 InstallOperation operation; 435 436 uint64_t total_blocks = BlocksInExtents(new_extents); 437 if (chunk_blocks == -1) 438 chunk_blocks = total_blocks; 439 440 for (uint64_t block_offset = 0; block_offset < total_blocks; 441 block_offset += chunk_blocks) { 442 // Split the old/new file in the same chunks. Note that this could drop 443 // some information from the old file used for the new chunk. If the old 444 // file is smaller (or even empty when there's no old file) the chunk will 445 // also be empty. 446 vector<Extent> old_extents_chunk = ExtentsSublist( 447 old_extents, block_offset, chunk_blocks); 448 vector<Extent> new_extents_chunk = ExtentsSublist( 449 new_extents, block_offset, chunk_blocks); 450 NormalizeExtents(&old_extents_chunk); 451 NormalizeExtents(&new_extents_chunk); 452 453 TEST_AND_RETURN_FALSE(ReadExtentsToDiff(old_part, 454 new_part, 455 old_extents_chunk, 456 new_extents_chunk, 457 version, 458 &data, 459 &operation)); 460 461 // Check if the operation writes nothing. 462 if (operation.dst_extents_size() == 0) { 463 if (operation.type() == InstallOperation::MOVE) { 464 LOG(INFO) << "Empty MOVE operation (" 465 << name << "), skipping"; 466 continue; 467 } else { 468 LOG(ERROR) << "Empty non-MOVE operation"; 469 return false; 470 } 471 } 472 473 // Now, insert into the list of operations. 474 AnnotatedOperation aop; 475 aop.name = name; 476 if (static_cast<uint64_t>(chunk_blocks) < total_blocks) { 477 aop.name = base::StringPrintf("%s:%" PRIu64, 478 name.c_str(), block_offset / chunk_blocks); 479 } 480 aop.op = operation; 481 482 // Write the data 483 TEST_AND_RETURN_FALSE(aop.SetOperationBlob(data, blob_file)); 484 aops->emplace_back(aop); 485 } 486 return true; 487 } 488 489 bool GenerateBestFullOperation(const brillo::Blob& new_data, 490 const PayloadVersion& version, 491 brillo::Blob* out_blob, 492 InstallOperation_Type* out_type) { 493 if (new_data.empty()) 494 return false; 495 496 if (version.OperationAllowed(InstallOperation::ZERO) && 497 std::all_of( 498 new_data.begin(), new_data.end(), [](uint8_t x) { return x == 0; })) { 499 // The read buffer is all zeros, so produce a ZERO operation. No need to 500 // check other types of operations in this case. 501 *out_blob = brillo::Blob(); 502 *out_type = InstallOperation::ZERO; 503 return true; 504 } 505 506 bool out_blob_set = false; 507 508 // Try compressing |new_data| with xz first. 509 if (version.OperationAllowed(InstallOperation::REPLACE_XZ)) { 510 brillo::Blob new_data_xz; 511 if (XzCompress(new_data, &new_data_xz) && !new_data_xz.empty()) { 512 *out_type = InstallOperation::REPLACE_XZ; 513 *out_blob = std::move(new_data_xz); 514 out_blob_set = true; 515 } 516 } 517 518 // Try compressing it with bzip2. 519 if (version.OperationAllowed(InstallOperation::REPLACE_BZ)) { 520 brillo::Blob new_data_bz; 521 // TODO(deymo): Implement some heuristic to determine if it is worth trying 522 // to compress the blob with bzip2 if we already have a good REPLACE_XZ. 523 if (BzipCompress(new_data, &new_data_bz) && !new_data_bz.empty() && 524 (!out_blob_set || out_blob->size() > new_data_bz.size())) { 525 // A REPLACE_BZ is better or nothing else was set. 526 *out_type = InstallOperation::REPLACE_BZ; 527 *out_blob = std::move(new_data_bz); 528 out_blob_set = true; 529 } 530 } 531 532 // If nothing else worked or it was badly compressed we try a REPLACE. 533 if (!out_blob_set || out_blob->size() >= new_data.size()) { 534 *out_type = InstallOperation::REPLACE; 535 // This needs to make a copy of the data in the case bzip or xz didn't 536 // compress well, which is not the common case so the performance hit is 537 // low. 538 *out_blob = new_data; 539 } 540 return true; 541 } 542 543 bool ReadExtentsToDiff(const string& old_part, 544 const string& new_part, 545 const vector<Extent>& old_extents, 546 const vector<Extent>& new_extents, 547 const PayloadVersion& version, 548 brillo::Blob* out_data, 549 InstallOperation* out_op) { 550 InstallOperation operation; 551 552 // We read blocks from old_extents and write blocks to new_extents. 553 uint64_t blocks_to_read = BlocksInExtents(old_extents); 554 uint64_t blocks_to_write = BlocksInExtents(new_extents); 555 556 // Disable bsdiff and imgdiff when the data is too big. 557 bool bsdiff_allowed = 558 version.OperationAllowed(InstallOperation::SOURCE_BSDIFF) || 559 version.OperationAllowed(InstallOperation::BSDIFF); 560 if (bsdiff_allowed && 561 blocks_to_read * kBlockSize > kMaxBsdiffDestinationSize) { 562 LOG(INFO) << "bsdiff blacklisted, data too big: " 563 << blocks_to_read * kBlockSize << " bytes"; 564 bsdiff_allowed = false; 565 } 566 567 bool imgdiff_allowed = version.OperationAllowed(InstallOperation::IMGDIFF); 568 if (imgdiff_allowed && 569 blocks_to_read * kBlockSize > kMaxImgdiffDestinationSize) { 570 LOG(INFO) << "imgdiff blacklisted, data too big: " 571 << blocks_to_read * kBlockSize << " bytes"; 572 imgdiff_allowed = false; 573 } 574 575 // Make copies of the extents so we can modify them. 576 vector<Extent> src_extents = old_extents; 577 vector<Extent> dst_extents = new_extents; 578 579 // Read in bytes from new data. 580 brillo::Blob new_data; 581 TEST_AND_RETURN_FALSE(utils::ReadExtents(new_part, 582 new_extents, 583 &new_data, 584 kBlockSize * blocks_to_write, 585 kBlockSize)); 586 TEST_AND_RETURN_FALSE(!new_data.empty()); 587 588 // Data blob that will be written to delta file. 589 brillo::Blob data_blob; 590 591 // Try generating a full operation for the given new data, regardless of the 592 // old_data. 593 InstallOperation_Type op_type; 594 TEST_AND_RETURN_FALSE( 595 GenerateBestFullOperation(new_data, version, &data_blob, &op_type)); 596 operation.set_type(op_type); 597 598 brillo::Blob old_data; 599 if (blocks_to_read > 0) { 600 // Read old data. 601 TEST_AND_RETURN_FALSE( 602 utils::ReadExtents(old_part, src_extents, &old_data, 603 kBlockSize * blocks_to_read, kBlockSize)); 604 if (old_data == new_data) { 605 // No change in data. 606 operation.set_type(version.OperationAllowed(InstallOperation::SOURCE_COPY) 607 ? InstallOperation::SOURCE_COPY 608 : InstallOperation::MOVE); 609 data_blob = brillo::Blob(); 610 } else if (bsdiff_allowed || imgdiff_allowed) { 611 // If the source file is considered bsdiff safe (no bsdiff bugs 612 // triggered), see if BSDIFF encoding is smaller. 613 base::FilePath old_chunk; 614 TEST_AND_RETURN_FALSE(base::CreateTemporaryFile(&old_chunk)); 615 ScopedPathUnlinker old_unlinker(old_chunk.value()); 616 TEST_AND_RETURN_FALSE(utils::WriteFile( 617 old_chunk.value().c_str(), old_data.data(), old_data.size())); 618 base::FilePath new_chunk; 619 TEST_AND_RETURN_FALSE(base::CreateTemporaryFile(&new_chunk)); 620 ScopedPathUnlinker new_unlinker(new_chunk.value()); 621 TEST_AND_RETURN_FALSE(utils::WriteFile( 622 new_chunk.value().c_str(), new_data.data(), new_data.size())); 623 624 if (bsdiff_allowed) { 625 brillo::Blob bsdiff_delta; 626 TEST_AND_RETURN_FALSE(DiffFiles( 627 kBsdiffPath, old_chunk.value(), new_chunk.value(), &bsdiff_delta)); 628 CHECK_GT(bsdiff_delta.size(), static_cast<brillo::Blob::size_type>(0)); 629 if (bsdiff_delta.size() < data_blob.size()) { 630 operation.set_type( 631 version.OperationAllowed(InstallOperation::SOURCE_BSDIFF) 632 ? InstallOperation::SOURCE_BSDIFF 633 : InstallOperation::BSDIFF); 634 data_blob = std::move(bsdiff_delta); 635 } 636 } 637 if (imgdiff_allowed && ContainsGZip(old_data) && ContainsGZip(new_data)) { 638 brillo::Blob imgdiff_delta; 639 // Imgdiff might fail in some cases, only use the result if it succeed, 640 // otherwise print the extents to analyze. 641 if (DiffFiles(kImgdiffPath, 642 old_chunk.value(), 643 new_chunk.value(), 644 &imgdiff_delta) && 645 imgdiff_delta.size() > 0) { 646 if (imgdiff_delta.size() < data_blob.size()) { 647 operation.set_type(InstallOperation::IMGDIFF); 648 data_blob = std::move(imgdiff_delta); 649 } 650 } else { 651 LOG(ERROR) << "Imgdiff failed with source extents: " 652 << ExtentsToString(src_extents) 653 << ", destination extents: " 654 << ExtentsToString(dst_extents); 655 } 656 } 657 } 658 } 659 660 size_t removed_bytes = 0; 661 // Remove identical src/dst block ranges in MOVE operations. 662 if (operation.type() == InstallOperation::MOVE) { 663 removed_bytes = RemoveIdenticalBlockRanges( 664 &src_extents, &dst_extents, new_data.size()); 665 } 666 // Set legacy src_length and dst_length fields. 667 operation.set_src_length(old_data.size() - removed_bytes); 668 operation.set_dst_length(new_data.size() - removed_bytes); 669 670 // Embed extents in the operation. 671 StoreExtents(src_extents, operation.mutable_src_extents()); 672 StoreExtents(dst_extents, operation.mutable_dst_extents()); 673 674 // Replace operations should not have source extents. 675 if (IsAReplaceOperation(operation.type())) { 676 operation.clear_src_extents(); 677 operation.clear_src_length(); 678 } 679 680 *out_data = std::move(data_blob); 681 *out_op = operation; 682 683 return true; 684 } 685 686 // Runs the bsdiff or imgdiff tool in |diff_path| on two files and returns the 687 // resulting delta in |out|. Returns true on success. 688 bool DiffFiles(const string& diff_path, 689 const string& old_file, 690 const string& new_file, 691 brillo::Blob* out) { 692 const string kPatchFile = "delta.patchXXXXXX"; 693 string patch_file_path; 694 695 TEST_AND_RETURN_FALSE( 696 utils::MakeTempFile(kPatchFile, &patch_file_path, nullptr)); 697 698 vector<string> cmd; 699 cmd.push_back(diff_path); 700 cmd.push_back(old_file); 701 cmd.push_back(new_file); 702 cmd.push_back(patch_file_path); 703 704 int rc = 1; 705 brillo::Blob patch_file; 706 string stdout; 707 TEST_AND_RETURN_FALSE(Subprocess::SynchronousExec(cmd, &rc, &stdout)); 708 if (rc != 0) { 709 LOG(ERROR) << diff_path << " returned " << rc << std::endl << stdout; 710 return false; 711 } 712 TEST_AND_RETURN_FALSE(utils::ReadFile(patch_file_path, out)); 713 unlink(patch_file_path.c_str()); 714 return true; 715 } 716 717 bool IsAReplaceOperation(InstallOperation_Type op_type) { 718 return (op_type == InstallOperation::REPLACE || 719 op_type == InstallOperation::REPLACE_BZ || 720 op_type == InstallOperation::REPLACE_XZ); 721 } 722 723 // Returns true if |op| is a no-op operation that doesn't do any useful work 724 // (e.g., a move operation that copies blocks onto themselves). 725 bool IsNoopOperation(const InstallOperation& op) { 726 return (op.type() == InstallOperation::MOVE && 727 ExpandExtents(op.src_extents()) == ExpandExtents(op.dst_extents())); 728 } 729 730 void FilterNoopOperations(vector<AnnotatedOperation>* ops) { 731 ops->erase( 732 std::remove_if( 733 ops->begin(), ops->end(), 734 [](const AnnotatedOperation& aop){return IsNoopOperation(aop.op);}), 735 ops->end()); 736 } 737 738 bool InitializePartitionInfo(const PartitionConfig& part, PartitionInfo* info) { 739 info->set_size(part.size); 740 HashCalculator hasher; 741 TEST_AND_RETURN_FALSE(hasher.UpdateFile(part.path, part.size) == 742 static_cast<off_t>(part.size)); 743 TEST_AND_RETURN_FALSE(hasher.Finalize()); 744 const brillo::Blob& hash = hasher.raw_hash(); 745 info->set_hash(hash.data(), hash.size()); 746 LOG(INFO) << part.path << ": size=" << part.size << " hash=" << hasher.hash(); 747 return true; 748 } 749 750 bool CompareAopsByDestination(AnnotatedOperation first_aop, 751 AnnotatedOperation second_aop) { 752 // We want empty operations to be at the end of the payload. 753 if (!first_aop.op.dst_extents().size() || !second_aop.op.dst_extents().size()) 754 return ((!first_aop.op.dst_extents().size()) < 755 (!second_aop.op.dst_extents().size())); 756 uint32_t first_dst_start = first_aop.op.dst_extents(0).start_block(); 757 uint32_t second_dst_start = second_aop.op.dst_extents(0).start_block(); 758 return first_dst_start < second_dst_start; 759 } 760 761 } // namespace diff_utils 762 763 } // namespace chromeos_update_engine 764
