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 lseek(fd, start, SEEK_SET); 426 while (start < len) { 427 size_t to_write = len - start; 428 if (to_write > 1<<20) to_write = 1<<20; 429 430 ssize_t written = write(fd, data+start, to_write); 431 if (written < 0) { 432 if (errno == EINTR) { 433 written = 0; 434 } else { 435 printf("failed write writing to %s (%s)\n", 436 partition, strerror(errno)); 437 return -1; 438 } 439 } 440 start += written; 441 } 442 if (fsync(fd) != 0) { 443 printf("failed to sync to %s (%s)\n", 444 partition, strerror(errno)); 445 return -1; 446 } 447 if (close(fd) != 0) { 448 printf("failed to close %s (%s)\n", 449 partition, strerror(errno)); 450 return -1; 451 } 452 fd = open(partition, O_RDONLY); 453 if (fd < 0) { 454 printf("failed to reopen %s for verify (%s)\n", 455 partition, strerror(errno)); 456 return -1; 457 } 458 459 // drop caches so our subsequent verification read 460 // won't just be reading the cache. 461 sync(); 462 int dc = open("/proc/sys/vm/drop_caches", O_WRONLY); 463 write(dc, "3\n", 2); 464 close(dc); 465 sleep(1); 466 printf(" caches dropped\n"); 467 468 // verify 469 lseek(fd, 0, SEEK_SET); 470 unsigned char buffer[4096]; 471 start = len; 472 size_t p; 473 for (p = 0; p < len; p += sizeof(buffer)) { 474 size_t to_read = len - p; 475 if (to_read > sizeof(buffer)) to_read = sizeof(buffer); 476 477 size_t so_far = 0; 478 while (so_far < to_read) { 479 ssize_t read_count = read(fd, buffer+so_far, to_read-so_far); 480 if (read_count < 0) { 481 if (errno == EINTR) { 482 read_count = 0; 483 } else { 484 printf("verify read error %s at %zu: %s\n", 485 partition, p, strerror(errno)); 486 return -1; 487 } 488 } 489 if ((size_t)read_count < to_read) { 490 printf("short verify read %s at %zu: %zd %zu %s\n", 491 partition, p, read_count, to_read, strerror(errno)); 492 } 493 so_far += read_count; 494 } 495 496 if (memcmp(buffer, data+p, to_read)) { 497 printf("verification failed starting at %zu\n", p); 498 start = p; 499 break; 500 } 501 } 502 503 if (start == len) { 504 printf("verification read succeeded (attempt %d)\n", attempt+1); 505 success = true; 506 break; 507 } 508 } 509 510 if (!success) { 511 printf("failed to verify after all attempts\n"); 512 return -1; 513 } 514 515 if (close(fd) != 0) { 516 printf("error closing %s (%s)\n", partition, strerror(errno)); 517 return -1; 518 } 519 sync(); 520 break; 521 } 522 } 523 524 free(copy); 525 return 0; 526 } 527 528 529 // Take a string 'str' of 40 hex digits and parse it into the 20 530 // byte array 'digest'. 'str' may contain only the digest or be of 531 // the form "<digest>:<anything>". Return 0 on success, -1 on any 532 // error. 533 int ParseSha1(const char* str, uint8_t* digest) { 534 int i; 535 const char* ps = str; 536 uint8_t* pd = digest; 537 for (i = 0; i < SHA_DIGEST_SIZE * 2; ++i, ++ps) { 538 int digit; 539 if (*ps >= '0' && *ps <= '9') { 540 digit = *ps - '0'; 541 } else if (*ps >= 'a' && *ps <= 'f') { 542 digit = *ps - 'a' + 10; 543 } else if (*ps >= 'A' && *ps <= 'F') { 544 digit = *ps - 'A' + 10; 545 } else { 546 return -1; 547 } 548 if (i % 2 == 0) { 549 *pd = digit << 4; 550 } else { 551 *pd |= digit; 552 ++pd; 553 } 554 } 555 if (*ps != '\0') return -1; 556 return 0; 557 } 558 559 // Search an array of sha1 strings for one matching the given sha1. 560 // Return the index of the match on success, or -1 if no match is 561 // found. 562 int FindMatchingPatch(uint8_t* sha1, char* const * const patch_sha1_str, 563 int num_patches) { 564 int i; 565 uint8_t patch_sha1[SHA_DIGEST_SIZE]; 566 for (i = 0; i < num_patches; ++i) { 567 if (ParseSha1(patch_sha1_str[i], patch_sha1) == 0 && 568 memcmp(patch_sha1, sha1, SHA_DIGEST_SIZE) == 0) { 569 return i; 570 } 571 } 572 return -1; 573 } 574 575 // Returns 0 if the contents of the file (argv[2]) or the cached file 576 // match any of the sha1's on the command line (argv[3:]). Returns 577 // nonzero otherwise. 578 int applypatch_check(const char* filename, 579 int num_patches, char** const patch_sha1_str) { 580 FileContents file; 581 file.data = NULL; 582 583 // It's okay to specify no sha1s; the check will pass if the 584 // LoadFileContents is successful. (Useful for reading 585 // partitions, where the filename encodes the sha1s; no need to 586 // check them twice.) 587 if (LoadFileContents(filename, &file) != 0 || 588 (num_patches > 0 && 589 FindMatchingPatch(file.sha1, patch_sha1_str, num_patches) < 0)) { 590 printf("file \"%s\" doesn't have any of expected " 591 "sha1 sums; checking cache\n", filename); 592 593 free(file.data); 594 file.data = NULL; 595 596 // If the source file is missing or corrupted, it might be because 597 // we were killed in the middle of patching it. A copy of it 598 // should have been made in CACHE_TEMP_SOURCE. If that file 599 // exists and matches the sha1 we're looking for, the check still 600 // passes. 601 602 if (LoadFileContents(CACHE_TEMP_SOURCE, &file) != 0) { 603 printf("failed to load cache file\n"); 604 return 1; 605 } 606 607 if (FindMatchingPatch(file.sha1, patch_sha1_str, num_patches) < 0) { 608 printf("cache bits don't match any sha1 for \"%s\"\n", filename); 609 free(file.data); 610 return 1; 611 } 612 } 613 614 free(file.data); 615 return 0; 616 } 617 618 int ShowLicenses() { 619 ShowBSDiffLicense(); 620 return 0; 621 } 622 623 ssize_t FileSink(const unsigned char* data, ssize_t len, void* token) { 624 int fd = *(int *)token; 625 ssize_t done = 0; 626 ssize_t wrote; 627 while (done < (ssize_t) len) { 628 wrote = write(fd, data+done, len-done); 629 if (wrote <= 0) { 630 printf("error writing %d bytes: %s\n", (int)(len-done), strerror(errno)); 631 return done; 632 } 633 done += wrote; 634 } 635 return done; 636 } 637 638 typedef struct { 639 unsigned char* buffer; 640 ssize_t size; 641 ssize_t pos; 642 } MemorySinkInfo; 643 644 ssize_t MemorySink(const unsigned char* data, ssize_t len, void* token) { 645 MemorySinkInfo* msi = (MemorySinkInfo*)token; 646 if (msi->size - msi->pos < len) { 647 return -1; 648 } 649 memcpy(msi->buffer + msi->pos, data, len); 650 msi->pos += len; 651 return len; 652 } 653 654 // Return the amount of free space (in bytes) on the filesystem 655 // containing filename. filename must exist. Return -1 on error. 656 size_t FreeSpaceForFile(const char* filename) { 657 struct statfs sf; 658 if (statfs(filename, &sf) != 0) { 659 printf("failed to statfs %s: %s\n", filename, strerror(errno)); 660 return -1; 661 } 662 return sf.f_bsize * sf.f_bfree; 663 } 664 665 int CacheSizeCheck(size_t bytes) { 666 if (MakeFreeSpaceOnCache(bytes) < 0) { 667 printf("unable to make %ld bytes available on /cache\n", (long)bytes); 668 return 1; 669 } else { 670 return 0; 671 } 672 } 673 674 static void print_short_sha1(const uint8_t sha1[SHA_DIGEST_SIZE]) { 675 int i; 676 const char* hex = "0123456789abcdef"; 677 for (i = 0; i < 4; ++i) { 678 putchar(hex[(sha1[i]>>4) & 0xf]); 679 putchar(hex[sha1[i] & 0xf]); 680 } 681 } 682 683 // This function applies binary patches to files in a way that is safe 684 // (the original file is not touched until we have the desired 685 // replacement for it) and idempotent (it's okay to run this program 686 // multiple times). 687 // 688 // - if the sha1 hash of <target_filename> is <target_sha1_string>, 689 // does nothing and exits successfully. 690 // 691 // - otherwise, if the sha1 hash of <source_filename> is one of the 692 // entries in <patch_sha1_str>, the corresponding patch from 693 // <patch_data> (which must be a VAL_BLOB) is applied to produce a 694 // new file (the type of patch is automatically detected from the 695 // blob daat). If that new file has sha1 hash <target_sha1_str>, 696 // moves it to replace <target_filename>, and exits successfully. 697 // Note that if <source_filename> and <target_filename> are not the 698 // same, <source_filename> is NOT deleted on success. 699 // <target_filename> may be the string "-" to mean "the same as 700 // source_filename". 701 // 702 // - otherwise, or if any error is encountered, exits with non-zero 703 // status. 704 // 705 // <source_filename> may refer to a partition to read the source data. 706 // See the comments for the LoadPartition Contents() function above 707 // for the format of such a filename. 708 709 int applypatch(const char* source_filename, 710 const char* target_filename, 711 const char* target_sha1_str, 712 size_t target_size, 713 int num_patches, 714 char** const patch_sha1_str, 715 Value** patch_data, 716 Value* bonus_data) { 717 printf("patch %s: ", source_filename); 718 719 if (target_filename[0] == '-' && 720 target_filename[1] == '\0') { 721 target_filename = source_filename; 722 } 723 724 uint8_t target_sha1[SHA_DIGEST_SIZE]; 725 if (ParseSha1(target_sha1_str, target_sha1) != 0) { 726 printf("failed to parse tgt-sha1 \"%s\"\n", target_sha1_str); 727 return 1; 728 } 729 730 FileContents copy_file; 731 FileContents source_file; 732 copy_file.data = NULL; 733 source_file.data = NULL; 734 const Value* source_patch_value = NULL; 735 const Value* copy_patch_value = NULL; 736 737 // We try to load the target file into the source_file object. 738 if (LoadFileContents(target_filename, &source_file) == 0) { 739 if (memcmp(source_file.sha1, target_sha1, SHA_DIGEST_SIZE) == 0) { 740 // The early-exit case: the patch was already applied, this file 741 // has the desired hash, nothing for us to do. 742 printf("already "); 743 print_short_sha1(target_sha1); 744 putchar('\n'); 745 free(source_file.data); 746 return 0; 747 } 748 } 749 750 if (source_file.data == NULL || 751 (target_filename != source_filename && 752 strcmp(target_filename, source_filename) != 0)) { 753 // Need to load the source file: either we failed to load the 754 // target file, or we did but it's different from the source file. 755 free(source_file.data); 756 source_file.data = NULL; 757 LoadFileContents(source_filename, &source_file); 758 } 759 760 if (source_file.data != NULL) { 761 int to_use = FindMatchingPatch(source_file.sha1, 762 patch_sha1_str, num_patches); 763 if (to_use >= 0) { 764 source_patch_value = patch_data[to_use]; 765 } 766 } 767 768 if (source_patch_value == NULL) { 769 free(source_file.data); 770 source_file.data = NULL; 771 printf("source file is bad; trying copy\n"); 772 773 if (LoadFileContents(CACHE_TEMP_SOURCE, ©_file) < 0) { 774 // fail. 775 printf("failed to read copy file\n"); 776 return 1; 777 } 778 779 int to_use = FindMatchingPatch(copy_file.sha1, 780 patch_sha1_str, num_patches); 781 if (to_use >= 0) { 782 copy_patch_value = patch_data[to_use]; 783 } 784 785 if (copy_patch_value == NULL) { 786 // fail. 787 printf("copy file doesn't match source SHA-1s either\n"); 788 free(copy_file.data); 789 return 1; 790 } 791 } 792 793 int result = GenerateTarget(&source_file, source_patch_value, 794 ©_file, copy_patch_value, 795 source_filename, target_filename, 796 target_sha1, target_size, bonus_data); 797 free(source_file.data); 798 free(copy_file.data); 799 800 return result; 801 } 802 803 static int GenerateTarget(FileContents* source_file, 804 const Value* source_patch_value, 805 FileContents* copy_file, 806 const Value* copy_patch_value, 807 const char* source_filename, 808 const char* target_filename, 809 const uint8_t target_sha1[SHA_DIGEST_SIZE], 810 size_t target_size, 811 const Value* bonus_data) { 812 int retry = 1; 813 SHA_CTX ctx; 814 int output; 815 MemorySinkInfo msi; 816 FileContents* source_to_use; 817 char* outname; 818 int made_copy = 0; 819 820 // assume that target_filename (eg "/system/app/Foo.apk") is located 821 // on the same filesystem as its top-level directory ("/system"). 822 // We need something that exists for calling statfs(). 823 char target_fs[strlen(target_filename)+1]; 824 char* slash = strchr(target_filename+1, '/'); 825 if (slash != NULL) { 826 int count = slash - target_filename; 827 strncpy(target_fs, target_filename, count); 828 target_fs[count] = '\0'; 829 } else { 830 strcpy(target_fs, target_filename); 831 } 832 833 do { 834 // Is there enough room in the target filesystem to hold the patched 835 // file? 836 837 if (strncmp(target_filename, "MTD:", 4) == 0 || 838 strncmp(target_filename, "EMMC:", 5) == 0) { 839 // If the target is a partition, we're actually going to 840 // write the output to /tmp and then copy it to the 841 // partition. statfs() always returns 0 blocks free for 842 // /tmp, so instead we'll just assume that /tmp has enough 843 // space to hold the file. 844 845 // We still write the original source to cache, in case 846 // the partition write is interrupted. 847 if (MakeFreeSpaceOnCache(source_file->size) < 0) { 848 printf("not enough free space on /cache\n"); 849 return 1; 850 } 851 if (SaveFileContents(CACHE_TEMP_SOURCE, source_file) < 0) { 852 printf("failed to back up source file\n"); 853 return 1; 854 } 855 made_copy = 1; 856 retry = 0; 857 } else { 858 int enough_space = 0; 859 if (retry > 0) { 860 size_t free_space = FreeSpaceForFile(target_fs); 861 enough_space = 862 (free_space > (256 << 10)) && // 256k (two-block) minimum 863 (free_space > (target_size * 3 / 2)); // 50% margin of error 864 if (!enough_space) { 865 printf("target %ld bytes; free space %ld bytes; retry %d; enough %d\n", 866 (long)target_size, (long)free_space, retry, enough_space); 867 } 868 } 869 870 if (!enough_space) { 871 retry = 0; 872 } 873 874 if (!enough_space && source_patch_value != NULL) { 875 // Using the original source, but not enough free space. First 876 // copy the source file to cache, then delete it from the original 877 // location. 878 879 if (strncmp(source_filename, "MTD:", 4) == 0 || 880 strncmp(source_filename, "EMMC:", 5) == 0) { 881 // It's impossible to free space on the target filesystem by 882 // deleting the source if the source is a partition. If 883 // we're ever in a state where we need to do this, fail. 884 printf("not enough free space for target but source " 885 "is partition\n"); 886 return 1; 887 } 888 889 if (MakeFreeSpaceOnCache(source_file->size) < 0) { 890 printf("not enough free space on /cache\n"); 891 return 1; 892 } 893 894 if (SaveFileContents(CACHE_TEMP_SOURCE, source_file) < 0) { 895 printf("failed to back up source file\n"); 896 return 1; 897 } 898 made_copy = 1; 899 unlink(source_filename); 900 901 size_t free_space = FreeSpaceForFile(target_fs); 902 printf("(now %ld bytes free for target) ", (long)free_space); 903 } 904 } 905 906 const Value* patch; 907 if (source_patch_value != NULL) { 908 source_to_use = source_file; 909 patch = source_patch_value; 910 } else { 911 source_to_use = copy_file; 912 patch = copy_patch_value; 913 } 914 915 if (patch->type != VAL_BLOB) { 916 printf("patch is not a blob\n"); 917 return 1; 918 } 919 920 SinkFn sink = NULL; 921 void* token = NULL; 922 output = -1; 923 outname = NULL; 924 if (strncmp(target_filename, "MTD:", 4) == 0 || 925 strncmp(target_filename, "EMMC:", 5) == 0) { 926 // We store the decoded output in memory. 927 msi.buffer = malloc(target_size); 928 if (msi.buffer == NULL) { 929 printf("failed to alloc %ld bytes for output\n", 930 (long)target_size); 931 return 1; 932 } 933 msi.pos = 0; 934 msi.size = target_size; 935 sink = MemorySink; 936 token = &msi; 937 } else { 938 // We write the decoded output to "<tgt-file>.patch". 939 outname = (char*)malloc(strlen(target_filename) + 10); 940 strcpy(outname, target_filename); 941 strcat(outname, ".patch"); 942 943 output = open(outname, O_WRONLY | O_CREAT | O_TRUNC | O_SYNC, 944 S_IRUSR | S_IWUSR); 945 if (output < 0) { 946 printf("failed to open output file %s: %s\n", 947 outname, strerror(errno)); 948 return 1; 949 } 950 sink = FileSink; 951 token = &output; 952 } 953 954 char* header = patch->data; 955 ssize_t header_bytes_read = patch->size; 956 957 SHA_init(&ctx); 958 959 int result; 960 961 if (header_bytes_read >= 8 && 962 memcmp(header, "BSDIFF40", 8) == 0) { 963 result = ApplyBSDiffPatch(source_to_use->data, source_to_use->size, 964 patch, 0, sink, token, &ctx); 965 } else if (header_bytes_read >= 8 && 966 memcmp(header, "IMGDIFF2", 8) == 0) { 967 result = ApplyImagePatch(source_to_use->data, source_to_use->size, 968 patch, sink, token, &ctx, bonus_data); 969 } else { 970 printf("Unknown patch file format\n"); 971 return 1; 972 } 973 974 if (output >= 0) { 975 if (fsync(output) != 0) { 976 printf("failed to fsync file \"%s\" (%s)\n", outname, strerror(errno)); 977 result = 1; 978 } 979 if (close(output) != 0) { 980 printf("failed to close file \"%s\" (%s)\n", outname, strerror(errno)); 981 result = 1; 982 } 983 } 984 985 if (result != 0) { 986 if (retry == 0) { 987 printf("applying patch failed\n"); 988 return result != 0; 989 } else { 990 printf("applying patch failed; retrying\n"); 991 } 992 if (outname != NULL) { 993 unlink(outname); 994 } 995 } else { 996 // succeeded; no need to retry 997 break; 998 } 999 } while (retry-- > 0); 1000 1001 const uint8_t* current_target_sha1 = SHA_final(&ctx); 1002 if (memcmp(current_target_sha1, target_sha1, SHA_DIGEST_SIZE) != 0) { 1003 printf("patch did not produce expected sha1\n"); 1004 return 1; 1005 } else { 1006 printf("now "); 1007 print_short_sha1(target_sha1); 1008 putchar('\n'); 1009 } 1010 1011 if (output < 0) { 1012 // Copy the temp file to the partition. 1013 if (WriteToPartition(msi.buffer, msi.pos, target_filename) != 0) { 1014 printf("write of patched data to %s failed\n", target_filename); 1015 return 1; 1016 } 1017 free(msi.buffer); 1018 } else { 1019 // Give the .patch file the same owner, group, and mode of the 1020 // original source file. 1021 if (chmod(outname, source_to_use->st.st_mode) != 0) { 1022 printf("chmod of \"%s\" failed: %s\n", outname, strerror(errno)); 1023 return 1; 1024 } 1025 if (chown(outname, source_to_use->st.st_uid, 1026 source_to_use->st.st_gid) != 0) { 1027 printf("chown of \"%s\" failed: %s\n", outname, strerror(errno)); 1028 return 1; 1029 } 1030 1031 // Finally, rename the .patch file to replace the target file. 1032 if (rename(outname, target_filename) != 0) { 1033 printf("rename of .patch to \"%s\" failed: %s\n", 1034 target_filename, strerror(errno)); 1035 return 1; 1036 } 1037 } 1038 1039 // If this run of applypatch created the copy, and we're here, we 1040 // can delete it. 1041 if (made_copy) unlink(CACHE_TEMP_SOURCE); 1042 1043 // Success! 1044 return 0; 1045 } 1046
