1 /* 2 * Copyright (C) 2008 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 <errno.h> 18 #include <fcntl.h> 19 #include <libgen.h> 20 #include <stdio.h> 21 #include <stdlib.h> 22 #include <string.h> 23 #include <sys/stat.h> 24 #include <sys/statfs.h> 25 #include <sys/types.h> 26 #include <unistd.h> 27 28 #include <memory> 29 #include <string> 30 31 #include <android-base/strings.h> 32 33 #include "openssl/sha.h" 34 #include "applypatch.h" 35 #include "mtdutils/mtdutils.h" 36 #include "edify/expr.h" 37 #include "ota_io.h" 38 #include "print_sha1.h" 39 40 static int LoadPartitionContents(const char* filename, FileContents* file); 41 static ssize_t FileSink(const unsigned char* data, ssize_t len, void* token); 42 static int GenerateTarget(FileContents* source_file, 43 const Value* source_patch_value, 44 FileContents* copy_file, 45 const Value* copy_patch_value, 46 const char* source_filename, 47 const char* target_filename, 48 const uint8_t target_sha1[SHA_DIGEST_LENGTH], 49 size_t target_size, 50 const Value* bonus_data); 51 52 static bool mtd_partitions_scanned = false; 53 54 // Read a file into memory; store the file contents and associated 55 // metadata in *file. 56 // 57 // Return 0 on success. 58 int LoadFileContents(const char* filename, FileContents* file) { 59 // A special 'filename' beginning with "MTD:" or "EMMC:" means to 60 // load the contents of a partition. 61 if (strncmp(filename, "MTD:", 4) == 0 || 62 strncmp(filename, "EMMC:", 5) == 0) { 63 return LoadPartitionContents(filename, file); 64 } 65 66 if (stat(filename, &file->st) != 0) { 67 printf("failed to stat \"%s\": %s\n", filename, strerror(errno)); 68 return -1; 69 } 70 71 std::vector<unsigned char> data(file->st.st_size); 72 FILE* f = ota_fopen(filename, "rb"); 73 if (f == NULL) { 74 printf("failed to open \"%s\": %s\n", filename, strerror(errno)); 75 return -1; 76 } 77 78 size_t bytes_read = ota_fread(data.data(), 1, data.size(), f); 79 if (bytes_read != data.size()) { 80 printf("short read of \"%s\" (%zu bytes of %zd)\n", filename, bytes_read, data.size()); 81 ota_fclose(f); 82 return -1; 83 } 84 ota_fclose(f); 85 file->data = std::move(data); 86 SHA1(file->data.data(), file->data.size(), file->sha1); 87 return 0; 88 } 89 90 // Load the contents of an MTD or EMMC partition into the provided 91 // FileContents. filename should be a string of the form 92 // "MTD:<partition_name>:<size_1>:<sha1_1>:<size_2>:<sha1_2>:..." (or 93 // "EMMC:<partition_device>:..."). The smallest size_n bytes for 94 // which that prefix of the partition contents has the corresponding 95 // sha1 hash will be loaded. It is acceptable for a size value to be 96 // repeated with different sha1s. Will return 0 on success. 97 // 98 // This complexity is needed because if an OTA installation is 99 // interrupted, the partition might contain either the source or the 100 // target data, which might be of different lengths. We need to know 101 // the length in order to read from a partition (there is no 102 // "end-of-file" marker), so the caller must specify the possible 103 // lengths and the hash of the data, and we'll do the load expecting 104 // to find one of those hashes. 105 enum PartitionType { MTD, EMMC }; 106 107 static int LoadPartitionContents(const char* filename, FileContents* file) { 108 std::string copy(filename); 109 std::vector<std::string> pieces = android::base::Split(copy, ":"); 110 if (pieces.size() < 4 || pieces.size() % 2 != 0) { 111 printf("LoadPartitionContents called with bad filename (%s)\n", filename); 112 return -1; 113 } 114 115 enum PartitionType type; 116 if (pieces[0] == "MTD") { 117 type = MTD; 118 } else if (pieces[0] == "EMMC") { 119 type = EMMC; 120 } else { 121 printf("LoadPartitionContents called with bad filename (%s)\n", filename); 122 return -1; 123 } 124 const char* partition = pieces[1].c_str(); 125 126 size_t pairs = (pieces.size() - 2) / 2; // # of (size, sha1) pairs in filename 127 std::vector<size_t> index(pairs); 128 std::vector<size_t> size(pairs); 129 std::vector<std::string> sha1sum(pairs); 130 131 for (size_t i = 0; i < pairs; ++i) { 132 size[i] = strtol(pieces[i*2+2].c_str(), NULL, 10); 133 if (size[i] == 0) { 134 printf("LoadPartitionContents called with bad size (%s)\n", filename); 135 return -1; 136 } 137 sha1sum[i] = pieces[i*2+3].c_str(); 138 index[i] = i; 139 } 140 141 // Sort the index[] array so it indexes the pairs in order of increasing size. 142 sort(index.begin(), index.end(), 143 [&](const size_t& i, const size_t& j) { 144 return (size[i] < size[j]); 145 } 146 ); 147 148 MtdReadContext* ctx = NULL; 149 FILE* dev = NULL; 150 151 switch (type) { 152 case MTD: { 153 if (!mtd_partitions_scanned) { 154 mtd_scan_partitions(); 155 mtd_partitions_scanned = true; 156 } 157 158 const MtdPartition* mtd = mtd_find_partition_by_name(partition); 159 if (mtd == NULL) { 160 printf("mtd partition \"%s\" not found (loading %s)\n", partition, filename); 161 return -1; 162 } 163 164 ctx = mtd_read_partition(mtd); 165 if (ctx == NULL) { 166 printf("failed to initialize read of mtd partition \"%s\"\n", partition); 167 return -1; 168 } 169 break; 170 } 171 172 case EMMC: 173 dev = ota_fopen(partition, "rb"); 174 if (dev == NULL) { 175 printf("failed to open emmc partition \"%s\": %s\n", partition, strerror(errno)); 176 return -1; 177 } 178 } 179 180 SHA_CTX sha_ctx; 181 SHA1_Init(&sha_ctx); 182 uint8_t parsed_sha[SHA_DIGEST_LENGTH]; 183 184 // Allocate enough memory to hold the largest size. 185 std::vector<unsigned char> data(size[index[pairs-1]]); 186 char* p = reinterpret_cast<char*>(data.data()); 187 size_t data_size = 0; // # bytes read so far 188 bool found = false; 189 190 for (size_t i = 0; i < pairs; ++i) { 191 // Read enough additional bytes to get us up to the next size. (Again, 192 // we're trying the possibilities in order of increasing size). 193 size_t next = size[index[i]] - data_size; 194 if (next > 0) { 195 size_t read = 0; 196 switch (type) { 197 case MTD: 198 read = mtd_read_data(ctx, p, next); 199 break; 200 201 case EMMC: 202 read = ota_fread(p, 1, next, dev); 203 break; 204 } 205 if (next != read) { 206 printf("short read (%zu bytes of %zu) for partition \"%s\"\n", 207 read, next, partition); 208 return -1; 209 } 210 SHA1_Update(&sha_ctx, p, read); 211 data_size += read; 212 p += read; 213 } 214 215 // Duplicate the SHA context and finalize the duplicate so we can 216 // check it against this pair's expected hash. 217 SHA_CTX temp_ctx; 218 memcpy(&temp_ctx, &sha_ctx, sizeof(SHA_CTX)); 219 uint8_t sha_so_far[SHA_DIGEST_LENGTH]; 220 SHA1_Final(sha_so_far, &temp_ctx); 221 222 if (ParseSha1(sha1sum[index[i]].c_str(), parsed_sha) != 0) { 223 printf("failed to parse sha1 %s in %s\n", sha1sum[index[i]].c_str(), filename); 224 return -1; 225 } 226 227 if (memcmp(sha_so_far, parsed_sha, SHA_DIGEST_LENGTH) == 0) { 228 // we have a match. stop reading the partition; we'll return 229 // the data we've read so far. 230 printf("partition read matched size %zu sha %s\n", 231 size[index[i]], sha1sum[index[i]].c_str()); 232 found = true; 233 break; 234 } 235 } 236 237 switch (type) { 238 case MTD: 239 mtd_read_close(ctx); 240 break; 241 242 case EMMC: 243 ota_fclose(dev); 244 break; 245 } 246 247 248 if (!found) { 249 // Ran off the end of the list of (size,sha1) pairs without finding a match. 250 printf("contents of partition \"%s\" didn't match %s\n", partition, filename); 251 return -1; 252 } 253 254 SHA1_Final(file->sha1, &sha_ctx); 255 256 data.resize(data_size); 257 file->data = std::move(data); 258 // Fake some stat() info. 259 file->st.st_mode = 0644; 260 file->st.st_uid = 0; 261 file->st.st_gid = 0; 262 263 return 0; 264 } 265 266 267 // Save the contents of the given FileContents object under the given 268 // filename. Return 0 on success. 269 int SaveFileContents(const char* filename, const FileContents* file) { 270 int fd = ota_open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_SYNC, S_IRUSR | S_IWUSR); 271 if (fd < 0) { 272 printf("failed to open \"%s\" for write: %s\n", filename, strerror(errno)); 273 return -1; 274 } 275 276 ssize_t bytes_written = FileSink(file->data.data(), file->data.size(), &fd); 277 if (bytes_written != static_cast<ssize_t>(file->data.size())) { 278 printf("short write of \"%s\" (%zd bytes of %zu) (%s)\n", 279 filename, bytes_written, file->data.size(), strerror(errno)); 280 ota_close(fd); 281 return -1; 282 } 283 if (ota_fsync(fd) != 0) { 284 printf("fsync of \"%s\" failed: %s\n", filename, strerror(errno)); 285 return -1; 286 } 287 if (ota_close(fd) != 0) { 288 printf("close of \"%s\" failed: %s\n", filename, strerror(errno)); 289 return -1; 290 } 291 292 if (chmod(filename, file->st.st_mode) != 0) { 293 printf("chmod of \"%s\" failed: %s\n", filename, strerror(errno)); 294 return -1; 295 } 296 if (chown(filename, file->st.st_uid, file->st.st_gid) != 0) { 297 printf("chown of \"%s\" failed: %s\n", filename, strerror(errno)); 298 return -1; 299 } 300 301 return 0; 302 } 303 304 // Write a memory buffer to 'target' partition, a string of the form 305 // "MTD:<partition>[:...]" or "EMMC:<partition_device>[:...]". The target name 306 // might contain multiple colons, but WriteToPartition() only uses the first 307 // two and ignores the rest. Return 0 on success. 308 int WriteToPartition(const unsigned char* data, size_t len, const char* target) { 309 std::string copy(target); 310 std::vector<std::string> pieces = android::base::Split(copy, ":"); 311 312 if (pieces.size() < 2) { 313 printf("WriteToPartition called with bad target (%s)\n", target); 314 return -1; 315 } 316 317 enum PartitionType type; 318 if (pieces[0] == "MTD") { 319 type = MTD; 320 } else if (pieces[0] == "EMMC") { 321 type = EMMC; 322 } else { 323 printf("WriteToPartition called with bad target (%s)\n", target); 324 return -1; 325 } 326 const char* partition = pieces[1].c_str(); 327 328 switch (type) { 329 case MTD: { 330 if (!mtd_partitions_scanned) { 331 mtd_scan_partitions(); 332 mtd_partitions_scanned = true; 333 } 334 335 const MtdPartition* mtd = mtd_find_partition_by_name(partition); 336 if (mtd == NULL) { 337 printf("mtd partition \"%s\" not found for writing\n", partition); 338 return -1; 339 } 340 341 MtdWriteContext* ctx = mtd_write_partition(mtd); 342 if (ctx == NULL) { 343 printf("failed to init mtd partition \"%s\" for writing\n", partition); 344 return -1; 345 } 346 347 size_t written = mtd_write_data(ctx, reinterpret_cast<const char*>(data), len); 348 if (written != len) { 349 printf("only wrote %zu of %zu bytes to MTD %s\n", written, len, partition); 350 mtd_write_close(ctx); 351 return -1; 352 } 353 354 if (mtd_erase_blocks(ctx, -1) < 0) { 355 printf("error finishing mtd write of %s\n", partition); 356 mtd_write_close(ctx); 357 return -1; 358 } 359 360 if (mtd_write_close(ctx)) { 361 printf("error closing mtd write of %s\n", partition); 362 return -1; 363 } 364 break; 365 } 366 367 case EMMC: { 368 size_t start = 0; 369 bool success = false; 370 int fd = ota_open(partition, O_RDWR | O_SYNC); 371 if (fd < 0) { 372 printf("failed to open %s: %s\n", partition, strerror(errno)); 373 return -1; 374 } 375 376 for (size_t attempt = 0; attempt < 2; ++attempt) { 377 if (TEMP_FAILURE_RETRY(lseek(fd, start, SEEK_SET)) == -1) { 378 printf("failed seek on %s: %s\n", partition, strerror(errno)); 379 return -1; 380 } 381 while (start < len) { 382 size_t to_write = len - start; 383 if (to_write > 1<<20) to_write = 1<<20; 384 385 ssize_t written = TEMP_FAILURE_RETRY(ota_write(fd, data+start, to_write)); 386 if (written == -1) { 387 printf("failed write writing to %s: %s\n", partition, strerror(errno)); 388 return -1; 389 } 390 start += written; 391 } 392 if (ota_fsync(fd) != 0) { 393 printf("failed to sync to %s (%s)\n", partition, strerror(errno)); 394 return -1; 395 } 396 if (ota_close(fd) != 0) { 397 printf("failed to close %s (%s)\n", partition, strerror(errno)); 398 return -1; 399 } 400 fd = ota_open(partition, O_RDONLY); 401 if (fd < 0) { 402 printf("failed to reopen %s for verify (%s)\n", partition, strerror(errno)); 403 return -1; 404 } 405 406 // Drop caches so our subsequent verification read 407 // won't just be reading the cache. 408 sync(); 409 int dc = ota_open("/proc/sys/vm/drop_caches", O_WRONLY); 410 if (TEMP_FAILURE_RETRY(ota_write(dc, "3\n", 2)) == -1) { 411 printf("write to /proc/sys/vm/drop_caches failed: %s\n", strerror(errno)); 412 } else { 413 printf(" caches dropped\n"); 414 } 415 ota_close(dc); 416 sleep(1); 417 418 // verify 419 if (TEMP_FAILURE_RETRY(lseek(fd, 0, SEEK_SET)) == -1) { 420 printf("failed to seek back to beginning of %s: %s\n", 421 partition, strerror(errno)); 422 return -1; 423 } 424 unsigned char buffer[4096]; 425 start = len; 426 for (size_t p = 0; p < len; p += sizeof(buffer)) { 427 size_t to_read = len - p; 428 if (to_read > sizeof(buffer)) { 429 to_read = sizeof(buffer); 430 } 431 432 size_t so_far = 0; 433 while (so_far < to_read) { 434 ssize_t read_count = 435 TEMP_FAILURE_RETRY(ota_read(fd, buffer+so_far, to_read-so_far)); 436 if (read_count == -1) { 437 printf("verify read error %s at %zu: %s\n", 438 partition, p, strerror(errno)); 439 return -1; 440 } 441 if (static_cast<size_t>(read_count) < to_read) { 442 printf("short verify read %s at %zu: %zd %zu %s\n", 443 partition, p, read_count, to_read, strerror(errno)); 444 } 445 so_far += read_count; 446 } 447 448 if (memcmp(buffer, data+p, to_read) != 0) { 449 printf("verification failed starting at %zu\n", p); 450 start = p; 451 break; 452 } 453 } 454 455 if (start == len) { 456 printf("verification read succeeded (attempt %zu)\n", attempt+1); 457 success = true; 458 break; 459 } 460 } 461 462 if (!success) { 463 printf("failed to verify after all attempts\n"); 464 return -1; 465 } 466 467 if (ota_close(fd) != 0) { 468 printf("error closing %s (%s)\n", partition, strerror(errno)); 469 return -1; 470 } 471 sync(); 472 break; 473 } 474 } 475 476 return 0; 477 } 478 479 480 // Take a string 'str' of 40 hex digits and parse it into the 20 481 // byte array 'digest'. 'str' may contain only the digest or be of 482 // the form "<digest>:<anything>". Return 0 on success, -1 on any 483 // error. 484 int ParseSha1(const char* str, uint8_t* digest) { 485 const char* ps = str; 486 uint8_t* pd = digest; 487 for (int i = 0; i < SHA_DIGEST_LENGTH * 2; ++i, ++ps) { 488 int digit; 489 if (*ps >= '0' && *ps <= '9') { 490 digit = *ps - '0'; 491 } else if (*ps >= 'a' && *ps <= 'f') { 492 digit = *ps - 'a' + 10; 493 } else if (*ps >= 'A' && *ps <= 'F') { 494 digit = *ps - 'A' + 10; 495 } else { 496 return -1; 497 } 498 if (i % 2 == 0) { 499 *pd = digit << 4; 500 } else { 501 *pd |= digit; 502 ++pd; 503 } 504 } 505 if (*ps != '\0') return -1; 506 return 0; 507 } 508 509 // Search an array of sha1 strings for one matching the given sha1. 510 // Return the index of the match on success, or -1 if no match is 511 // found. 512 int FindMatchingPatch(uint8_t* sha1, char* const * const patch_sha1_str, 513 int num_patches) { 514 uint8_t patch_sha1[SHA_DIGEST_LENGTH]; 515 for (int i = 0; i < num_patches; ++i) { 516 if (ParseSha1(patch_sha1_str[i], patch_sha1) == 0 && 517 memcmp(patch_sha1, sha1, SHA_DIGEST_LENGTH) == 0) { 518 return i; 519 } 520 } 521 return -1; 522 } 523 524 // Returns 0 if the contents of the file (argv[2]) or the cached file 525 // match any of the sha1's on the command line (argv[3:]). Returns 526 // nonzero otherwise. 527 int applypatch_check(const char* filename, int num_patches, 528 char** const patch_sha1_str) { 529 FileContents file; 530 531 // It's okay to specify no sha1s; the check will pass if the 532 // LoadFileContents is successful. (Useful for reading 533 // partitions, where the filename encodes the sha1s; no need to 534 // check them twice.) 535 if (LoadFileContents(filename, &file) != 0 || 536 (num_patches > 0 && 537 FindMatchingPatch(file.sha1, patch_sha1_str, num_patches) < 0)) { 538 printf("file \"%s\" doesn't have any of expected " 539 "sha1 sums; checking cache\n", filename); 540 541 // If the source file is missing or corrupted, it might be because 542 // we were killed in the middle of patching it. A copy of it 543 // should have been made in CACHE_TEMP_SOURCE. If that file 544 // exists and matches the sha1 we're looking for, the check still 545 // passes. 546 547 if (LoadFileContents(CACHE_TEMP_SOURCE, &file) != 0) { 548 printf("failed to load cache file\n"); 549 return 1; 550 } 551 552 if (FindMatchingPatch(file.sha1, patch_sha1_str, num_patches) < 0) { 553 printf("cache bits don't match any sha1 for \"%s\"\n", filename); 554 return 1; 555 } 556 } 557 return 0; 558 } 559 560 int ShowLicenses() { 561 ShowBSDiffLicense(); 562 return 0; 563 } 564 565 ssize_t FileSink(const unsigned char* data, ssize_t len, void* token) { 566 int fd = *static_cast<int*>(token); 567 ssize_t done = 0; 568 ssize_t wrote; 569 while (done < len) { 570 wrote = TEMP_FAILURE_RETRY(ota_write(fd, data+done, len-done)); 571 if (wrote == -1) { 572 printf("error writing %zd bytes: %s\n", (len-done), strerror(errno)); 573 return done; 574 } 575 done += wrote; 576 } 577 return done; 578 } 579 580 ssize_t MemorySink(const unsigned char* data, ssize_t len, void* token) { 581 std::string* s = static_cast<std::string*>(token); 582 s->append(reinterpret_cast<const char*>(data), len); 583 return len; 584 } 585 586 // Return the amount of free space (in bytes) on the filesystem 587 // containing filename. filename must exist. Return -1 on error. 588 size_t FreeSpaceForFile(const char* filename) { 589 struct statfs sf; 590 if (statfs(filename, &sf) != 0) { 591 printf("failed to statfs %s: %s\n", filename, strerror(errno)); 592 return -1; 593 } 594 return sf.f_bsize * sf.f_bavail; 595 } 596 597 int CacheSizeCheck(size_t bytes) { 598 if (MakeFreeSpaceOnCache(bytes) < 0) { 599 printf("unable to make %ld bytes available on /cache\n", (long)bytes); 600 return 1; 601 } else { 602 return 0; 603 } 604 } 605 606 // This function applies binary patches to files in a way that is safe 607 // (the original file is not touched until we have the desired 608 // replacement for it) and idempotent (it's okay to run this program 609 // multiple times). 610 // 611 // - if the sha1 hash of <target_filename> is <target_sha1_string>, 612 // does nothing and exits successfully. 613 // 614 // - otherwise, if the sha1 hash of <source_filename> is one of the 615 // entries in <patch_sha1_str>, the corresponding patch from 616 // <patch_data> (which must be a VAL_BLOB) is applied to produce a 617 // new file (the type of patch is automatically detected from the 618 // blob data). If that new file has sha1 hash <target_sha1_str>, 619 // moves it to replace <target_filename>, and exits successfully. 620 // Note that if <source_filename> and <target_filename> are not the 621 // same, <source_filename> is NOT deleted on success. 622 // <target_filename> may be the string "-" to mean "the same as 623 // source_filename". 624 // 625 // - otherwise, or if any error is encountered, exits with non-zero 626 // status. 627 // 628 // <source_filename> may refer to a partition to read the source data. 629 // See the comments for the LoadPartitionContents() function above 630 // for the format of such a filename. 631 632 int applypatch(const char* source_filename, 633 const char* target_filename, 634 const char* target_sha1_str, 635 size_t target_size, 636 int num_patches, 637 char** const patch_sha1_str, 638 Value** patch_data, 639 Value* bonus_data) { 640 printf("patch %s: ", source_filename); 641 642 if (target_filename[0] == '-' && target_filename[1] == '\0') { 643 target_filename = source_filename; 644 } 645 646 uint8_t target_sha1[SHA_DIGEST_LENGTH]; 647 if (ParseSha1(target_sha1_str, target_sha1) != 0) { 648 printf("failed to parse tgt-sha1 \"%s\"\n", target_sha1_str); 649 return 1; 650 } 651 652 FileContents copy_file; 653 FileContents source_file; 654 const Value* source_patch_value = NULL; 655 const Value* copy_patch_value = NULL; 656 657 // We try to load the target file into the source_file object. 658 if (LoadFileContents(target_filename, &source_file) == 0) { 659 if (memcmp(source_file.sha1, target_sha1, SHA_DIGEST_LENGTH) == 0) { 660 // The early-exit case: the patch was already applied, this file 661 // has the desired hash, nothing for us to do. 662 printf("already %s\n", short_sha1(target_sha1).c_str()); 663 return 0; 664 } 665 } 666 667 if (source_file.data.empty() || 668 (target_filename != source_filename && 669 strcmp(target_filename, source_filename) != 0)) { 670 // Need to load the source file: either we failed to load the 671 // target file, or we did but it's different from the source file. 672 source_file.data.clear(); 673 LoadFileContents(source_filename, &source_file); 674 } 675 676 if (!source_file.data.empty()) { 677 int to_use = FindMatchingPatch(source_file.sha1, patch_sha1_str, num_patches); 678 if (to_use >= 0) { 679 source_patch_value = patch_data[to_use]; 680 } 681 } 682 683 if (source_patch_value == NULL) { 684 source_file.data.clear(); 685 printf("source file is bad; trying copy\n"); 686 687 if (LoadFileContents(CACHE_TEMP_SOURCE, ©_file) < 0) { 688 // fail. 689 printf("failed to read copy file\n"); 690 return 1; 691 } 692 693 int to_use = FindMatchingPatch(copy_file.sha1, patch_sha1_str, num_patches); 694 if (to_use >= 0) { 695 copy_patch_value = patch_data[to_use]; 696 } 697 698 if (copy_patch_value == NULL) { 699 // fail. 700 printf("copy file doesn't match source SHA-1s either\n"); 701 return 1; 702 } 703 } 704 705 return GenerateTarget(&source_file, source_patch_value, 706 ©_file, copy_patch_value, 707 source_filename, target_filename, 708 target_sha1, target_size, bonus_data); 709 } 710 711 /* 712 * This function flashes a given image to the target partition. It verifies 713 * the target cheksum first, and will return if target has the desired hash. 714 * It checks the checksum of the given source image before flashing, and 715 * verifies the target partition afterwards. The function is idempotent. 716 * Returns zero on success. 717 */ 718 int applypatch_flash(const char* source_filename, const char* target_filename, 719 const char* target_sha1_str, size_t target_size) { 720 printf("flash %s: ", target_filename); 721 722 uint8_t target_sha1[SHA_DIGEST_LENGTH]; 723 if (ParseSha1(target_sha1_str, target_sha1) != 0) { 724 printf("failed to parse tgt-sha1 \"%s\"\n", target_sha1_str); 725 return 1; 726 } 727 728 FileContents source_file; 729 std::string target_str(target_filename); 730 731 std::vector<std::string> pieces = android::base::Split(target_str, ":"); 732 if (pieces.size() != 2 || (pieces[0] != "MTD" && pieces[0] != "EMMC")) { 733 printf("invalid target name \"%s\"", target_filename); 734 return 1; 735 } 736 737 // Load the target into the source_file object to see if already applied. 738 pieces.push_back(std::to_string(target_size)); 739 pieces.push_back(target_sha1_str); 740 std::string fullname = android::base::Join(pieces, ':'); 741 if (LoadPartitionContents(fullname.c_str(), &source_file) == 0 && 742 memcmp(source_file.sha1, target_sha1, SHA_DIGEST_LENGTH) == 0) { 743 // The early-exit case: the image was already applied, this partition 744 // has the desired hash, nothing for us to do. 745 printf("already %s\n", short_sha1(target_sha1).c_str()); 746 return 0; 747 } 748 749 if (LoadFileContents(source_filename, &source_file) == 0) { 750 if (memcmp(source_file.sha1, target_sha1, SHA_DIGEST_LENGTH) != 0) { 751 // The source doesn't have desired checksum. 752 printf("source \"%s\" doesn't have expected sha1 sum\n", source_filename); 753 printf("expected: %s, found: %s\n", short_sha1(target_sha1).c_str(), 754 short_sha1(source_file.sha1).c_str()); 755 return 1; 756 } 757 } 758 759 if (WriteToPartition(source_file.data.data(), target_size, target_filename) != 0) { 760 printf("write of copied data to %s failed\n", target_filename); 761 return 1; 762 } 763 return 0; 764 } 765 766 static int GenerateTarget(FileContents* source_file, 767 const Value* source_patch_value, 768 FileContents* copy_file, 769 const Value* copy_patch_value, 770 const char* source_filename, 771 const char* target_filename, 772 const uint8_t target_sha1[SHA_DIGEST_LENGTH], 773 size_t target_size, 774 const Value* bonus_data) { 775 int retry = 1; 776 SHA_CTX ctx; 777 std::string memory_sink_str; 778 FileContents* source_to_use; 779 int made_copy = 0; 780 781 bool target_is_partition = (strncmp(target_filename, "MTD:", 4) == 0 || 782 strncmp(target_filename, "EMMC:", 5) == 0); 783 const std::string tmp_target_filename = std::string(target_filename) + ".patch"; 784 785 // assume that target_filename (eg "/system/app/Foo.apk") is located 786 // on the same filesystem as its top-level directory ("/system"). 787 // We need something that exists for calling statfs(). 788 std::string target_fs = target_filename; 789 auto slash_pos = target_fs.find('/', 1); 790 if (slash_pos != std::string::npos) { 791 target_fs.resize(slash_pos); 792 } 793 794 const Value* patch; 795 if (source_patch_value != NULL) { 796 source_to_use = source_file; 797 patch = source_patch_value; 798 } else { 799 source_to_use = copy_file; 800 patch = copy_patch_value; 801 } 802 if (patch->type != VAL_BLOB) { 803 printf("patch is not a blob\n"); 804 return 1; 805 } 806 char* header = patch->data; 807 ssize_t header_bytes_read = patch->size; 808 bool use_bsdiff = false; 809 if (header_bytes_read >= 8 && memcmp(header, "BSDIFF40", 8) == 0) { 810 use_bsdiff = true; 811 } else if (header_bytes_read >= 8 && memcmp(header, "IMGDIFF2", 8) == 0) { 812 use_bsdiff = false; 813 } else { 814 printf("Unknown patch file format\n"); 815 return 1; 816 } 817 818 do { 819 // Is there enough room in the target filesystem to hold the patched 820 // file? 821 822 if (target_is_partition) { 823 // If the target is a partition, we're actually going to 824 // write the output to /tmp and then copy it to the 825 // partition. statfs() always returns 0 blocks free for 826 // /tmp, so instead we'll just assume that /tmp has enough 827 // space to hold the file. 828 829 // We still write the original source to cache, in case 830 // the partition write is interrupted. 831 if (MakeFreeSpaceOnCache(source_file->data.size()) < 0) { 832 printf("not enough free space on /cache\n"); 833 return 1; 834 } 835 if (SaveFileContents(CACHE_TEMP_SOURCE, source_file) < 0) { 836 printf("failed to back up source file\n"); 837 return 1; 838 } 839 made_copy = 1; 840 retry = 0; 841 } else { 842 int enough_space = 0; 843 if (retry > 0) { 844 size_t free_space = FreeSpaceForFile(target_fs.c_str()); 845 enough_space = 846 (free_space > (256 << 10)) && // 256k (two-block) minimum 847 (free_space > (target_size * 3 / 2)); // 50% margin of error 848 if (!enough_space) { 849 printf("target %zu bytes; free space %zu bytes; retry %d; enough %d\n", 850 target_size, free_space, retry, enough_space); 851 } 852 } 853 854 if (!enough_space) { 855 retry = 0; 856 } 857 858 if (!enough_space && source_patch_value != NULL) { 859 // Using the original source, but not enough free space. First 860 // copy the source file to cache, then delete it from the original 861 // location. 862 863 if (strncmp(source_filename, "MTD:", 4) == 0 || 864 strncmp(source_filename, "EMMC:", 5) == 0) { 865 // It's impossible to free space on the target filesystem by 866 // deleting the source if the source is a partition. If 867 // we're ever in a state where we need to do this, fail. 868 printf("not enough free space for target but source is partition\n"); 869 return 1; 870 } 871 872 if (MakeFreeSpaceOnCache(source_file->data.size()) < 0) { 873 printf("not enough free space on /cache\n"); 874 return 1; 875 } 876 877 if (SaveFileContents(CACHE_TEMP_SOURCE, source_file) < 0) { 878 printf("failed to back up source file\n"); 879 return 1; 880 } 881 made_copy = 1; 882 unlink(source_filename); 883 884 size_t free_space = FreeSpaceForFile(target_fs.c_str()); 885 printf("(now %zu bytes free for target) ", free_space); 886 } 887 } 888 889 890 SinkFn sink = NULL; 891 void* token = NULL; 892 int output_fd = -1; 893 if (target_is_partition) { 894 // We store the decoded output in memory. 895 sink = MemorySink; 896 token = &memory_sink_str; 897 } else { 898 // We write the decoded output to "<tgt-file>.patch". 899 output_fd = ota_open(tmp_target_filename.c_str(), O_WRONLY | O_CREAT | O_TRUNC | O_SYNC, 900 S_IRUSR | S_IWUSR); 901 if (output_fd < 0) { 902 printf("failed to open output file %s: %s\n", tmp_target_filename.c_str(), 903 strerror(errno)); 904 return 1; 905 } 906 sink = FileSink; 907 token = &output_fd; 908 } 909 910 911 SHA1_Init(&ctx); 912 913 int result; 914 if (use_bsdiff) { 915 result = ApplyBSDiffPatch(source_to_use->data.data(), source_to_use->data.size(), 916 patch, 0, sink, token, &ctx); 917 } else { 918 result = ApplyImagePatch(source_to_use->data.data(), source_to_use->data.size(), 919 patch, sink, token, &ctx, bonus_data); 920 } 921 922 if (!target_is_partition) { 923 if (ota_fsync(output_fd) != 0) { 924 printf("failed to fsync file \"%s\" (%s)\n", tmp_target_filename.c_str(), 925 strerror(errno)); 926 result = 1; 927 } 928 if (ota_close(output_fd) != 0) { 929 printf("failed to close file \"%s\" (%s)\n", tmp_target_filename.c_str(), 930 strerror(errno)); 931 result = 1; 932 } 933 } 934 935 if (result != 0) { 936 if (retry == 0) { 937 printf("applying patch failed\n"); 938 return result != 0; 939 } else { 940 printf("applying patch failed; retrying\n"); 941 } 942 if (!target_is_partition) { 943 unlink(tmp_target_filename.c_str()); 944 } 945 } else { 946 // succeeded; no need to retry 947 break; 948 } 949 } while (retry-- > 0); 950 951 uint8_t current_target_sha1[SHA_DIGEST_LENGTH]; 952 SHA1_Final(current_target_sha1, &ctx); 953 if (memcmp(current_target_sha1, target_sha1, SHA_DIGEST_LENGTH) != 0) { 954 printf("patch did not produce expected sha1\n"); 955 return 1; 956 } else { 957 printf("now %s\n", short_sha1(target_sha1).c_str()); 958 } 959 960 if (target_is_partition) { 961 // Copy the temp file to the partition. 962 if (WriteToPartition(reinterpret_cast<const unsigned char*>(memory_sink_str.c_str()), 963 memory_sink_str.size(), target_filename) != 0) { 964 printf("write of patched data to %s failed\n", target_filename); 965 return 1; 966 } 967 } else { 968 // Give the .patch file the same owner, group, and mode of the 969 // original source file. 970 if (chmod(tmp_target_filename.c_str(), source_to_use->st.st_mode) != 0) { 971 printf("chmod of \"%s\" failed: %s\n", tmp_target_filename.c_str(), strerror(errno)); 972 return 1; 973 } 974 if (chown(tmp_target_filename.c_str(), source_to_use->st.st_uid, source_to_use->st.st_gid) != 0) { 975 printf("chown of \"%s\" failed: %s\n", tmp_target_filename.c_str(), strerror(errno)); 976 return 1; 977 } 978 979 // Finally, rename the .patch file to replace the target file. 980 if (rename(tmp_target_filename.c_str(), target_filename) != 0) { 981 printf("rename of .patch to \"%s\" failed: %s\n", target_filename, strerror(errno)); 982 return 1; 983 } 984 } 985 986 // If this run of applypatch created the copy, and we're here, we 987 // can delete it. 988 if (made_copy) { 989 unlink(CACHE_TEMP_SOURCE); 990 } 991 992 // Success! 993 return 0; 994 } 995