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 <libgen.h> 19 #include <stdio.h> 20 #include <stdlib.h> 21 #include <string.h> 22 #include <sys/stat.h> 23 #include <sys/statfs.h> 24 #include <sys/types.h> 25 #include <fcntl.h> 26 #include <unistd.h> 27 #include <stdbool.h> 28 29 #include "mincrypt/sha.h" 30 #include "applypatch.h" 31 #include "mtdutils/mtdutils.h" 32 #include "edify/expr.h" 33 34 static int LoadPartitionContents(const char* filename, FileContents* file); 35 static ssize_t FileSink(const unsigned char* data, ssize_t len, void* token); 36 static int GenerateTarget(FileContents* source_file, 37 const Value* source_patch_value, 38 FileContents* copy_file, 39 const Value* copy_patch_value, 40 const char* source_filename, 41 const char* target_filename, 42 const uint8_t target_sha1[SHA_DIGEST_SIZE], 43 size_t target_size, 44 const Value* bonus_data); 45 46 static int mtd_partitions_scanned = 0; 47 48 // Read a file into memory; store the file contents and associated 49 // metadata in *file. 50 // 51 // Return 0 on success. 52 int LoadFileContents(const char* filename, FileContents* file) { 53 file->data = NULL; 54 55 // A special 'filename' beginning with "MTD:" or "EMMC:" means to 56 // load the contents of a partition. 57 if (strncmp(filename, "MTD:", 4) == 0 || 58 strncmp(filename, "EMMC:", 5) == 0) { 59 return LoadPartitionContents(filename, file); 60 } 61 62 if (stat(filename, &file->st) != 0) { 63 printf("failed to stat \"%s\": %s\n", filename, strerror(errno)); 64 return -1; 65 } 66 67 file->size = file->st.st_size; 68 file->data = malloc(file->size); 69 70 FILE* f = fopen(filename, "rb"); 71 if (f == NULL) { 72 printf("failed to open \"%s\": %s\n", filename, strerror(errno)); 73 free(file->data); 74 file->data = NULL; 75 return -1; 76 } 77 78 ssize_t bytes_read = fread(file->data, 1, file->size, f); 79 if (bytes_read != file->size) { 80 printf("short read of \"%s\" (%ld bytes of %ld)\n", 81 filename, (long)bytes_read, (long)file->size); 82 free(file->data); 83 file->data = NULL; 84 return -1; 85 } 86 fclose(f); 87 88 SHA_hash(file->data, file->size, file->sha1); 89 return 0; 90 } 91 92 static size_t* size_array; 93 // comparison function for qsort()ing an int array of indexes into 94 // size_array[]. 95 static int compare_size_indices(const void* a, const void* b) { 96 int aa = *(int*)a; 97 int bb = *(int*)b; 98 if (size_array[aa] < size_array[bb]) { 99 return -1; 100 } else if (size_array[aa] > size_array[bb]) { 101 return 1; 102 } else { 103 return 0; 104 } 105 } 106 107 // Load the contents of an MTD or EMMC partition into the provided 108 // FileContents. filename should be a string of the form 109 // "MTD:<partition_name>:<size_1>:<sha1_1>:<size_2>:<sha1_2>:..." (or 110 // "EMMC:<partition_device>:..."). The smallest size_n bytes for 111 // which that prefix of the partition contents has the corresponding 112 // sha1 hash will be loaded. It is acceptable for a size value to be 113 // repeated with different sha1s. Will return 0 on success. 114 // 115 // This complexity is needed because if an OTA installation is 116 // interrupted, the partition might contain either the source or the 117 // target data, which might be of different lengths. We need to know 118 // the length in order to read from a partition (there is no 119 // "end-of-file" marker), so the caller must specify the possible 120 // lengths and the hash of the data, and we'll do the load expecting 121 // to find one of those hashes. 122 enum PartitionType { MTD, EMMC }; 123 124 static int LoadPartitionContents(const char* filename, FileContents* file) { 125 char* copy = strdup(filename); 126 const char* magic = strtok(copy, ":"); 127 128 enum PartitionType type; 129 130 if (strcmp(magic, "MTD") == 0) { 131 type = MTD; 132 } else if (strcmp(magic, "EMMC") == 0) { 133 type = EMMC; 134 } else { 135 printf("LoadPartitionContents called with bad filename (%s)\n", 136 filename); 137 return -1; 138 } 139 const char* partition = strtok(NULL, ":"); 140 141 int i; 142 int colons = 0; 143 for (i = 0; filename[i] != '\0'; ++i) { 144 if (filename[i] == ':') { 145 ++colons; 146 } 147 } 148 if (colons < 3 || colons%2 == 0) { 149 printf("LoadPartitionContents called with bad filename (%s)\n", 150 filename); 151 } 152 153 int pairs = (colons-1)/2; // # of (size,sha1) pairs in filename 154 int* index = malloc(pairs * sizeof(int)); 155 size_t* size = malloc(pairs * sizeof(size_t)); 156 char** sha1sum = malloc(pairs * sizeof(char*)); 157 158 for (i = 0; i < pairs; ++i) { 159 const char* size_str = strtok(NULL, ":"); 160 size[i] = strtol(size_str, NULL, 10); 161 if (size[i] == 0) { 162 printf("LoadPartitionContents called with bad size (%s)\n", filename); 163 return -1; 164 } 165 sha1sum[i] = strtok(NULL, ":"); 166 index[i] = i; 167 } 168 169 // sort the index[] array so it indexes the pairs in order of 170 // increasing size. 171 size_array = size; 172 qsort(index, pairs, sizeof(int), compare_size_indices); 173 174 MtdReadContext* ctx = NULL; 175 FILE* dev = NULL; 176 177 switch (type) { 178 case MTD: 179 if (!mtd_partitions_scanned) { 180 mtd_scan_partitions(); 181 mtd_partitions_scanned = 1; 182 } 183 184 const MtdPartition* mtd = mtd_find_partition_by_name(partition); 185 if (mtd == NULL) { 186 printf("mtd partition \"%s\" not found (loading %s)\n", 187 partition, filename); 188 return -1; 189 } 190 191 ctx = mtd_read_partition(mtd); 192 if (ctx == NULL) { 193 printf("failed to initialize read of mtd partition \"%s\"\n", 194 partition); 195 return -1; 196 } 197 break; 198 199 case EMMC: 200 dev = fopen(partition, "rb"); 201 if (dev == NULL) { 202 printf("failed to open emmc partition \"%s\": %s\n", 203 partition, strerror(errno)); 204 return -1; 205 } 206 } 207 208 SHA_CTX sha_ctx; 209 SHA_init(&sha_ctx); 210 uint8_t parsed_sha[SHA_DIGEST_SIZE]; 211 212 // allocate enough memory to hold the largest size. 213 file->data = malloc(size[index[pairs-1]]); 214 char* p = (char*)file->data; 215 file->size = 0; // # bytes read so far 216 217 for (i = 0; i < pairs; ++i) { 218 // Read enough additional bytes to get us up to the next size 219 // (again, we're trying the possibilities in order of increasing 220 // size). 221 size_t next = size[index[i]] - file->size; 222 size_t read = 0; 223 if (next > 0) { 224 switch (type) { 225 case MTD: 226 read = mtd_read_data(ctx, p, next); 227 break; 228 229 case EMMC: 230 read = fread(p, 1, next, dev); 231 break; 232 } 233 if (next != read) { 234 printf("short read (%zu bytes of %zu) for partition \"%s\"\n", 235 read, next, partition); 236 free(file->data); 237 file->data = NULL; 238 return -1; 239 } 240 SHA_update(&sha_ctx, p, read); 241 file->size += read; 242 } 243 244 // Duplicate the SHA context and finalize the duplicate so we can 245 // check it against this pair's expected hash. 246 SHA_CTX temp_ctx; 247 memcpy(&temp_ctx, &sha_ctx, sizeof(SHA_CTX)); 248 const uint8_t* sha_so_far = SHA_final(&temp_ctx); 249 250 if (ParseSha1(sha1sum[index[i]], parsed_sha) != 0) { 251 printf("failed to parse sha1 %s in %s\n", 252 sha1sum[index[i]], filename); 253 free(file->data); 254 file->data = NULL; 255 return -1; 256 } 257 258 if (memcmp(sha_so_far, parsed_sha, SHA_DIGEST_SIZE) == 0) { 259 // we have a match. stop reading the partition; we'll return 260 // the data we've read so far. 261 printf("partition read matched size %zu sha %s\n", 262 size[index[i]], sha1sum[index[i]]); 263 break; 264 } 265 266 p += read; 267 } 268 269 switch (type) { 270 case MTD: 271 mtd_read_close(ctx); 272 break; 273 274 case EMMC: 275 fclose(dev); 276 break; 277 } 278 279 280 if (i == pairs) { 281 // Ran off the end of the list of (size,sha1) pairs without 282 // finding a match. 283 printf("contents of partition \"%s\" didn't match %s\n", 284 partition, filename); 285 free(file->data); 286 file->data = NULL; 287 return -1; 288 } 289 290 const uint8_t* sha_final = SHA_final(&sha_ctx); 291 for (i = 0; i < SHA_DIGEST_SIZE; ++i) { 292 file->sha1[i] = sha_final[i]; 293 } 294 295 // Fake some stat() info. 296 file->st.st_mode = 0644; 297 file->st.st_uid = 0; 298 file->st.st_gid = 0; 299 300 free(copy); 301 free(index); 302 free(size); 303 free(sha1sum); 304 305 return 0; 306 } 307 308 309 // Save the contents of the given FileContents object under the given 310 // filename. Return 0 on success. 311 int SaveFileContents(const char* filename, const FileContents* file) { 312 int fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_SYNC, S_IRUSR | S_IWUSR); 313 if (fd < 0) { 314 printf("failed to open \"%s\" for write: %s\n", 315 filename, strerror(errno)); 316 return -1; 317 } 318 319 ssize_t bytes_written = FileSink(file->data, file->size, &fd); 320 if (bytes_written != file->size) { 321 printf("short write of \"%s\" (%ld bytes of %ld) (%s)\n", 322 filename, (long)bytes_written, (long)file->size, 323 strerror(errno)); 324 close(fd); 325 return -1; 326 } 327 if (fsync(fd) != 0) { 328 printf("fsync of \"%s\" failed: %s\n", filename, strerror(errno)); 329 return -1; 330 } 331 if (close(fd) != 0) { 332 printf("close of \"%s\" failed: %s\n", filename, strerror(errno)); 333 return -1; 334 } 335 336 if (chmod(filename, file->st.st_mode) != 0) { 337 printf("chmod of \"%s\" failed: %s\n", filename, strerror(errno)); 338 return -1; 339 } 340 if (chown(filename, file->st.st_uid, file->st.st_gid) != 0) { 341 printf("chown of \"%s\" failed: %s\n", filename, strerror(errno)); 342 return -1; 343 } 344 345 return 0; 346 } 347 348 // Write a memory buffer to 'target' partition, a string of the form 349 // "MTD:<partition>[:...]" or "EMMC:<partition_device>:". Return 0 on 350 // success. 351 int WriteToPartition(unsigned char* data, size_t len, 352 const char* target) { 353 char* copy = strdup(target); 354 const char* magic = strtok(copy, ":"); 355 356 enum PartitionType type; 357 if (strcmp(magic, "MTD") == 0) { 358 type = MTD; 359 } else if (strcmp(magic, "EMMC") == 0) { 360 type = EMMC; 361 } else { 362 printf("WriteToPartition called with bad target (%s)\n", target); 363 return -1; 364 } 365 const char* partition = strtok(NULL, ":"); 366 367 if (partition == NULL) { 368 printf("bad partition target name \"%s\"\n", target); 369 return -1; 370 } 371 372 switch (type) { 373 case MTD: 374 if (!mtd_partitions_scanned) { 375 mtd_scan_partitions(); 376 mtd_partitions_scanned = 1; 377 } 378 379 const MtdPartition* mtd = mtd_find_partition_by_name(partition); 380 if (mtd == NULL) { 381 printf("mtd partition \"%s\" not found for writing\n", 382 partition); 383 return -1; 384 } 385 386 MtdWriteContext* ctx = mtd_write_partition(mtd); 387 if (ctx == NULL) { 388 printf("failed to init mtd partition \"%s\" for writing\n", 389 partition); 390 return -1; 391 } 392 393 size_t written = mtd_write_data(ctx, (char*)data, len); 394 if (written != len) { 395 printf("only wrote %zu of %zu bytes to MTD %s\n", 396 written, len, partition); 397 mtd_write_close(ctx); 398 return -1; 399 } 400 401 if (mtd_erase_blocks(ctx, -1) < 0) { 402 printf("error finishing mtd write of %s\n", partition); 403 mtd_write_close(ctx); 404 return -1; 405 } 406 407 if (mtd_write_close(ctx)) { 408 printf("error closing mtd write of %s\n", partition); 409 return -1; 410 } 411 break; 412 413 case EMMC: 414 { 415 size_t start = 0; 416 int success = 0; 417 int fd = open(partition, O_RDWR | O_SYNC); 418 if (fd < 0) { 419 printf("failed to open %s: %s\n", partition, strerror(errno)); 420 return -1; 421 } 422 int attempt; 423 424 for (attempt = 0; attempt < 2; ++attempt) { 425 if (TEMP_FAILURE_RETRY(lseek(fd, start, SEEK_SET)) == -1) { 426 printf("failed seek on %s: %s\n", 427 partition, strerror(errno)); 428 return -1; 429 } 430 while (start < len) { 431 size_t to_write = len - start; 432 if (to_write > 1<<20) to_write = 1<<20; 433 434 ssize_t written = TEMP_FAILURE_RETRY(write(fd, data+start, to_write)); 435 if (written == -1) { 436 printf("failed write writing to %s: %s\n", partition, strerror(errno)); 437 return -1; 438 } 439 start += written; 440 } 441 if (fsync(fd) != 0) { 442 printf("failed to sync to %s (%s)\n", 443 partition, strerror(errno)); 444 return -1; 445 } 446 if (close(fd) != 0) { 447 printf("failed to close %s (%s)\n", 448 partition, strerror(errno)); 449 return -1; 450 } 451 fd = open(partition, O_RDONLY); 452 if (fd < 0) { 453 printf("failed to reopen %s for verify (%s)\n", 454 partition, strerror(errno)); 455 return -1; 456 } 457 458 // drop caches so our subsequent verification read 459 // won't just be reading the cache. 460 sync(); 461 int dc = open("/proc/sys/vm/drop_caches", O_WRONLY); 462 if (TEMP_FAILURE_RETRY(write(dc, "3\n", 2)) == -1) { 463 printf("write to /proc/sys/vm/drop_caches failed: %s\n", strerror(errno)); 464 } else { 465 printf(" caches dropped\n"); 466 } 467 close(dc); 468 sleep(1); 469 470 // verify 471 if (TEMP_FAILURE_RETRY(lseek(fd, 0, SEEK_SET)) == -1) { 472 printf("failed to seek back to beginning of %s: %s\n", 473 partition, strerror(errno)); 474 return -1; 475 } 476 unsigned char buffer[4096]; 477 start = len; 478 size_t p; 479 for (p = 0; p < len; p += sizeof(buffer)) { 480 size_t to_read = len - p; 481 if (to_read > sizeof(buffer)) to_read = sizeof(buffer); 482 483 size_t so_far = 0; 484 while (so_far < to_read) { 485 ssize_t read_count = 486 TEMP_FAILURE_RETRY(read(fd, buffer+so_far, to_read-so_far)); 487 if (read_count == -1) { 488 printf("verify read error %s at %zu: %s\n", 489 partition, p, strerror(errno)); 490 return -1; 491 } 492 if ((size_t)read_count < to_read) { 493 printf("short verify read %s at %zu: %zd %zu %s\n", 494 partition, p, read_count, to_read, strerror(errno)); 495 } 496 so_far += read_count; 497 } 498 499 if (memcmp(buffer, data+p, to_read)) { 500 printf("verification failed starting at %zu\n", p); 501 start = p; 502 break; 503 } 504 } 505 506 if (start == len) { 507 printf("verification read succeeded (attempt %d)\n", attempt+1); 508 success = true; 509 break; 510 } 511 } 512 513 if (!success) { 514 printf("failed to verify after all attempts\n"); 515 return -1; 516 } 517 518 if (close(fd) != 0) { 519 printf("error closing %s (%s)\n", partition, strerror(errno)); 520 return -1; 521 } 522 sync(); 523 break; 524 } 525 } 526 527 free(copy); 528 return 0; 529 } 530 531 532 // Take a string 'str' of 40 hex digits and parse it into the 20 533 // byte array 'digest'. 'str' may contain only the digest or be of 534 // the form "<digest>:<anything>". Return 0 on success, -1 on any 535 // error. 536 int ParseSha1(const char* str, uint8_t* digest) { 537 int i; 538 const char* ps = str; 539 uint8_t* pd = digest; 540 for (i = 0; i < SHA_DIGEST_SIZE * 2; ++i, ++ps) { 541 int digit; 542 if (*ps >= '0' && *ps <= '9') { 543 digit = *ps - '0'; 544 } else if (*ps >= 'a' && *ps <= 'f') { 545 digit = *ps - 'a' + 10; 546 } else if (*ps >= 'A' && *ps <= 'F') { 547 digit = *ps - 'A' + 10; 548 } else { 549 return -1; 550 } 551 if (i % 2 == 0) { 552 *pd = digit << 4; 553 } else { 554 *pd |= digit; 555 ++pd; 556 } 557 } 558 if (*ps != '\0') return -1; 559 return 0; 560 } 561 562 // Search an array of sha1 strings for one matching the given sha1. 563 // Return the index of the match on success, or -1 if no match is 564 // found. 565 int FindMatchingPatch(uint8_t* sha1, char* const * const patch_sha1_str, 566 int num_patches) { 567 int i; 568 uint8_t patch_sha1[SHA_DIGEST_SIZE]; 569 for (i = 0; i < num_patches; ++i) { 570 if (ParseSha1(patch_sha1_str[i], patch_sha1) == 0 && 571 memcmp(patch_sha1, sha1, SHA_DIGEST_SIZE) == 0) { 572 return i; 573 } 574 } 575 return -1; 576 } 577 578 // Returns 0 if the contents of the file (argv[2]) or the cached file 579 // match any of the sha1's on the command line (argv[3:]). Returns 580 // nonzero otherwise. 581 int applypatch_check(const char* filename, 582 int num_patches, char** const patch_sha1_str) { 583 FileContents file; 584 file.data = NULL; 585 586 // It's okay to specify no sha1s; the check will pass if the 587 // LoadFileContents is successful. (Useful for reading 588 // partitions, where the filename encodes the sha1s; no need to 589 // check them twice.) 590 if (LoadFileContents(filename, &file) != 0 || 591 (num_patches > 0 && 592 FindMatchingPatch(file.sha1, patch_sha1_str, num_patches) < 0)) { 593 printf("file \"%s\" doesn't have any of expected " 594 "sha1 sums; checking cache\n", filename); 595 596 free(file.data); 597 file.data = NULL; 598 599 // If the source file is missing or corrupted, it might be because 600 // we were killed in the middle of patching it. A copy of it 601 // should have been made in CACHE_TEMP_SOURCE. If that file 602 // exists and matches the sha1 we're looking for, the check still 603 // passes. 604 605 if (LoadFileContents(CACHE_TEMP_SOURCE, &file) != 0) { 606 printf("failed to load cache file\n"); 607 return 1; 608 } 609 610 if (FindMatchingPatch(file.sha1, patch_sha1_str, num_patches) < 0) { 611 printf("cache bits don't match any sha1 for \"%s\"\n", filename); 612 free(file.data); 613 return 1; 614 } 615 } 616 617 free(file.data); 618 return 0; 619 } 620 621 int ShowLicenses() { 622 ShowBSDiffLicense(); 623 return 0; 624 } 625 626 ssize_t FileSink(const unsigned char* data, ssize_t len, void* token) { 627 int fd = *(int *)token; 628 ssize_t done = 0; 629 ssize_t wrote; 630 while (done < (ssize_t) len) { 631 wrote = TEMP_FAILURE_RETRY(write(fd, data+done, len-done)); 632 if (wrote == -1) { 633 printf("error writing %d bytes: %s\n", (int)(len-done), strerror(errno)); 634 return done; 635 } 636 done += wrote; 637 } 638 return done; 639 } 640 641 typedef struct { 642 unsigned char* buffer; 643 ssize_t size; 644 ssize_t pos; 645 } MemorySinkInfo; 646 647 ssize_t MemorySink(const unsigned char* data, ssize_t len, void* token) { 648 MemorySinkInfo* msi = (MemorySinkInfo*)token; 649 if (msi->size - msi->pos < len) { 650 return -1; 651 } 652 memcpy(msi->buffer + msi->pos, data, len); 653 msi->pos += len; 654 return len; 655 } 656 657 // Return the amount of free space (in bytes) on the filesystem 658 // containing filename. filename must exist. Return -1 on error. 659 size_t FreeSpaceForFile(const char* filename) { 660 struct statfs sf; 661 if (statfs(filename, &sf) != 0) { 662 printf("failed to statfs %s: %s\n", filename, strerror(errno)); 663 return -1; 664 } 665 return sf.f_bsize * sf.f_bavail; 666 } 667 668 int CacheSizeCheck(size_t bytes) { 669 if (MakeFreeSpaceOnCache(bytes) < 0) { 670 printf("unable to make %ld bytes available on /cache\n", (long)bytes); 671 return 1; 672 } else { 673 return 0; 674 } 675 } 676 677 static void print_short_sha1(const uint8_t sha1[SHA_DIGEST_SIZE]) { 678 int i; 679 const char* hex = "0123456789abcdef"; 680 for (i = 0; i < 4; ++i) { 681 putchar(hex[(sha1[i]>>4) & 0xf]); 682 putchar(hex[sha1[i] & 0xf]); 683 } 684 } 685 686 // This function applies binary patches to files in a way that is safe 687 // (the original file is not touched until we have the desired 688 // replacement for it) and idempotent (it's okay to run this program 689 // multiple times). 690 // 691 // - if the sha1 hash of <target_filename> is <target_sha1_string>, 692 // does nothing and exits successfully. 693 // 694 // - otherwise, if the sha1 hash of <source_filename> is one of the 695 // entries in <patch_sha1_str>, the corresponding patch from 696 // <patch_data> (which must be a VAL_BLOB) is applied to produce a 697 // new file (the type of patch is automatically detected from the 698 // blob daat). If that new file has sha1 hash <target_sha1_str>, 699 // moves it to replace <target_filename>, and exits successfully. 700 // Note that if <source_filename> and <target_filename> are not the 701 // same, <source_filename> is NOT deleted on success. 702 // <target_filename> may be the string "-" to mean "the same as 703 // source_filename". 704 // 705 // - otherwise, or if any error is encountered, exits with non-zero 706 // status. 707 // 708 // <source_filename> may refer to a partition to read the source data. 709 // See the comments for the LoadPartition Contents() function above 710 // for the format of such a filename. 711 712 int applypatch(const char* source_filename, 713 const char* target_filename, 714 const char* target_sha1_str, 715 size_t target_size, 716 int num_patches, 717 char** const patch_sha1_str, 718 Value** patch_data, 719 Value* bonus_data) { 720 printf("patch %s: ", source_filename); 721 722 if (target_filename[0] == '-' && 723 target_filename[1] == '\0') { 724 target_filename = source_filename; 725 } 726 727 uint8_t target_sha1[SHA_DIGEST_SIZE]; 728 if (ParseSha1(target_sha1_str, target_sha1) != 0) { 729 printf("failed to parse tgt-sha1 \"%s\"\n", target_sha1_str); 730 return 1; 731 } 732 733 FileContents copy_file; 734 FileContents source_file; 735 copy_file.data = NULL; 736 source_file.data = NULL; 737 const Value* source_patch_value = NULL; 738 const Value* copy_patch_value = NULL; 739 740 // We try to load the target file into the source_file object. 741 if (LoadFileContents(target_filename, &source_file) == 0) { 742 if (memcmp(source_file.sha1, target_sha1, SHA_DIGEST_SIZE) == 0) { 743 // The early-exit case: the patch was already applied, this file 744 // has the desired hash, nothing for us to do. 745 printf("already "); 746 print_short_sha1(target_sha1); 747 putchar('\n'); 748 free(source_file.data); 749 return 0; 750 } 751 } 752 753 if (source_file.data == NULL || 754 (target_filename != source_filename && 755 strcmp(target_filename, source_filename) != 0)) { 756 // Need to load the source file: either we failed to load the 757 // target file, or we did but it's different from the source file. 758 free(source_file.data); 759 source_file.data = NULL; 760 LoadFileContents(source_filename, &source_file); 761 } 762 763 if (source_file.data != NULL) { 764 int to_use = FindMatchingPatch(source_file.sha1, 765 patch_sha1_str, num_patches); 766 if (to_use >= 0) { 767 source_patch_value = patch_data[to_use]; 768 } 769 } 770 771 if (source_patch_value == NULL) { 772 free(source_file.data); 773 source_file.data = NULL; 774 printf("source file is bad; trying copy\n"); 775 776 if (LoadFileContents(CACHE_TEMP_SOURCE, ©_file) < 0) { 777 // fail. 778 printf("failed to read copy file\n"); 779 return 1; 780 } 781 782 int to_use = FindMatchingPatch(copy_file.sha1, 783 patch_sha1_str, num_patches); 784 if (to_use >= 0) { 785 copy_patch_value = patch_data[to_use]; 786 } 787 788 if (copy_patch_value == NULL) { 789 // fail. 790 printf("copy file doesn't match source SHA-1s either\n"); 791 free(copy_file.data); 792 return 1; 793 } 794 } 795 796 int result = GenerateTarget(&source_file, source_patch_value, 797 ©_file, copy_patch_value, 798 source_filename, target_filename, 799 target_sha1, target_size, bonus_data); 800 free(source_file.data); 801 free(copy_file.data); 802 803 return result; 804 } 805 806 static int GenerateTarget(FileContents* source_file, 807 const Value* source_patch_value, 808 FileContents* copy_file, 809 const Value* copy_patch_value, 810 const char* source_filename, 811 const char* target_filename, 812 const uint8_t target_sha1[SHA_DIGEST_SIZE], 813 size_t target_size, 814 const Value* bonus_data) { 815 int retry = 1; 816 SHA_CTX ctx; 817 int output; 818 MemorySinkInfo msi; 819 FileContents* source_to_use; 820 char* outname; 821 int made_copy = 0; 822 823 // assume that target_filename (eg "/system/app/Foo.apk") is located 824 // on the same filesystem as its top-level directory ("/system"). 825 // We need something that exists for calling statfs(). 826 char target_fs[strlen(target_filename)+1]; 827 char* slash = strchr(target_filename+1, '/'); 828 if (slash != NULL) { 829 int count = slash - target_filename; 830 strncpy(target_fs, target_filename, count); 831 target_fs[count] = '\0'; 832 } else { 833 strcpy(target_fs, target_filename); 834 } 835 836 do { 837 // Is there enough room in the target filesystem to hold the patched 838 // file? 839 840 if (strncmp(target_filename, "MTD:", 4) == 0 || 841 strncmp(target_filename, "EMMC:", 5) == 0) { 842 // If the target is a partition, we're actually going to 843 // write the output to /tmp and then copy it to the 844 // partition. statfs() always returns 0 blocks free for 845 // /tmp, so instead we'll just assume that /tmp has enough 846 // space to hold the file. 847 848 // We still write the original source to cache, in case 849 // the partition write is interrupted. 850 if (MakeFreeSpaceOnCache(source_file->size) < 0) { 851 printf("not enough free space on /cache\n"); 852 return 1; 853 } 854 if (SaveFileContents(CACHE_TEMP_SOURCE, source_file) < 0) { 855 printf("failed to back up source file\n"); 856 return 1; 857 } 858 made_copy = 1; 859 retry = 0; 860 } else { 861 int enough_space = 0; 862 if (retry > 0) { 863 size_t free_space = FreeSpaceForFile(target_fs); 864 enough_space = 865 (free_space > (256 << 10)) && // 256k (two-block) minimum 866 (free_space > (target_size * 3 / 2)); // 50% margin of error 867 if (!enough_space) { 868 printf("target %ld bytes; free space %ld bytes; retry %d; enough %d\n", 869 (long)target_size, (long)free_space, retry, enough_space); 870 } 871 } 872 873 if (!enough_space) { 874 retry = 0; 875 } 876 877 if (!enough_space && source_patch_value != NULL) { 878 // Using the original source, but not enough free space. First 879 // copy the source file to cache, then delete it from the original 880 // location. 881 882 if (strncmp(source_filename, "MTD:", 4) == 0 || 883 strncmp(source_filename, "EMMC:", 5) == 0) { 884 // It's impossible to free space on the target filesystem by 885 // deleting the source if the source is a partition. If 886 // we're ever in a state where we need to do this, fail. 887 printf("not enough free space for target but source " 888 "is partition\n"); 889 return 1; 890 } 891 892 if (MakeFreeSpaceOnCache(source_file->size) < 0) { 893 printf("not enough free space on /cache\n"); 894 return 1; 895 } 896 897 if (SaveFileContents(CACHE_TEMP_SOURCE, source_file) < 0) { 898 printf("failed to back up source file\n"); 899 return 1; 900 } 901 made_copy = 1; 902 unlink(source_filename); 903 904 size_t free_space = FreeSpaceForFile(target_fs); 905 printf("(now %ld bytes free for target) ", (long)free_space); 906 } 907 } 908 909 const Value* patch; 910 if (source_patch_value != NULL) { 911 source_to_use = source_file; 912 patch = source_patch_value; 913 } else { 914 source_to_use = copy_file; 915 patch = copy_patch_value; 916 } 917 918 if (patch->type != VAL_BLOB) { 919 printf("patch is not a blob\n"); 920 return 1; 921 } 922 923 SinkFn sink = NULL; 924 void* token = NULL; 925 output = -1; 926 outname = NULL; 927 if (strncmp(target_filename, "MTD:", 4) == 0 || 928 strncmp(target_filename, "EMMC:", 5) == 0) { 929 // We store the decoded output in memory. 930 msi.buffer = malloc(target_size); 931 if (msi.buffer == NULL) { 932 printf("failed to alloc %ld bytes for output\n", 933 (long)target_size); 934 return 1; 935 } 936 msi.pos = 0; 937 msi.size = target_size; 938 sink = MemorySink; 939 token = &msi; 940 } else { 941 // We write the decoded output to "<tgt-file>.patch". 942 outname = (char*)malloc(strlen(target_filename) + 10); 943 strcpy(outname, target_filename); 944 strcat(outname, ".patch"); 945 946 output = open(outname, O_WRONLY | O_CREAT | O_TRUNC | O_SYNC, 947 S_IRUSR | S_IWUSR); 948 if (output < 0) { 949 printf("failed to open output file %s: %s\n", 950 outname, strerror(errno)); 951 return 1; 952 } 953 sink = FileSink; 954 token = &output; 955 } 956 957 char* header = patch->data; 958 ssize_t header_bytes_read = patch->size; 959 960 SHA_init(&ctx); 961 962 int result; 963 964 if (header_bytes_read >= 8 && 965 memcmp(header, "BSDIFF40", 8) == 0) { 966 result = ApplyBSDiffPatch(source_to_use->data, source_to_use->size, 967 patch, 0, sink, token, &ctx); 968 } else if (header_bytes_read >= 8 && 969 memcmp(header, "IMGDIFF2", 8) == 0) { 970 result = ApplyImagePatch(source_to_use->data, source_to_use->size, 971 patch, sink, token, &ctx, bonus_data); 972 } else { 973 printf("Unknown patch file format\n"); 974 return 1; 975 } 976 977 if (output >= 0) { 978 if (fsync(output) != 0) { 979 printf("failed to fsync file \"%s\" (%s)\n", outname, strerror(errno)); 980 result = 1; 981 } 982 if (close(output) != 0) { 983 printf("failed to close file \"%s\" (%s)\n", outname, strerror(errno)); 984 result = 1; 985 } 986 } 987 988 if (result != 0) { 989 if (retry == 0) { 990 printf("applying patch failed\n"); 991 return result != 0; 992 } else { 993 printf("applying patch failed; retrying\n"); 994 } 995 if (outname != NULL) { 996 unlink(outname); 997 } 998 } else { 999 // succeeded; no need to retry 1000 break; 1001 } 1002 } while (retry-- > 0); 1003 1004 const uint8_t* current_target_sha1 = SHA_final(&ctx); 1005 if (memcmp(current_target_sha1, target_sha1, SHA_DIGEST_SIZE) != 0) { 1006 printf("patch did not produce expected sha1\n"); 1007 return 1; 1008 } else { 1009 printf("now "); 1010 print_short_sha1(target_sha1); 1011 putchar('\n'); 1012 } 1013 1014 if (output < 0) { 1015 // Copy the temp file to the partition. 1016 if (WriteToPartition(msi.buffer, msi.pos, target_filename) != 0) { 1017 printf("write of patched data to %s failed\n", target_filename); 1018 return 1; 1019 } 1020 free(msi.buffer); 1021 } else { 1022 // Give the .patch file the same owner, group, and mode of the 1023 // original source file. 1024 if (chmod(outname, source_to_use->st.st_mode) != 0) { 1025 printf("chmod of \"%s\" failed: %s\n", outname, strerror(errno)); 1026 return 1; 1027 } 1028 if (chown(outname, source_to_use->st.st_uid, 1029 source_to_use->st.st_gid) != 0) { 1030 printf("chown of \"%s\" failed: %s\n", outname, strerror(errno)); 1031 return 1; 1032 } 1033 1034 // Finally, rename the .patch file to replace the target file. 1035 if (rename(outname, target_filename) != 0) { 1036 printf("rename of .patch to \"%s\" failed: %s\n", 1037 target_filename, strerror(errno)); 1038 return 1; 1039 } 1040 } 1041 1042 // If this run of applypatch created the copy, and we're here, we 1043 // can delete it. 1044 if (made_copy) unlink(CACHE_TEMP_SOURCE); 1045 1046 // Success! 1047 return 0; 1048 } 1049