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 28 #include "mincrypt/sha.h" 29 #include "applypatch.h" 30 #include "mtdutils/mtdutils.h" 31 #include "edify/expr.h" 32 33 static int LoadPartitionContents(const char* filename, FileContents* file); 34 static ssize_t FileSink(unsigned char* data, ssize_t len, void* token); 35 static int GenerateTarget(FileContents* source_file, 36 const Value* source_patch_value, 37 FileContents* copy_file, 38 const Value* copy_patch_value, 39 const char* source_filename, 40 const char* target_filename, 41 const uint8_t target_sha1[SHA_DIGEST_SIZE], 42 size_t target_size, 43 const Value* bonus_data); 44 45 static int mtd_partitions_scanned = 0; 46 47 // Read a file into memory; optionally (retouch_flag == RETOUCH_DO_MASK) mask 48 // the retouched entries back to their original value (such that SHA-1 checks 49 // don't fail due to randomization); store the file contents and associated 50 // metadata in *file. 51 // 52 // Return 0 on success. 53 int LoadFileContents(const char* filename, FileContents* file, 54 int retouch_flag) { 55 file->data = NULL; 56 57 // A special 'filename' beginning with "MTD:" or "EMMC:" means to 58 // load the contents of a partition. 59 if (strncmp(filename, "MTD:", 4) == 0 || 60 strncmp(filename, "EMMC:", 5) == 0) { 61 return LoadPartitionContents(filename, file); 62 } 63 64 if (stat(filename, &file->st) != 0) { 65 printf("failed to stat \"%s\": %s\n", filename, strerror(errno)); 66 return -1; 67 } 68 69 file->size = file->st.st_size; 70 file->data = malloc(file->size); 71 72 FILE* f = fopen(filename, "rb"); 73 if (f == NULL) { 74 printf("failed to open \"%s\": %s\n", filename, strerror(errno)); 75 free(file->data); 76 file->data = NULL; 77 return -1; 78 } 79 80 ssize_t bytes_read = fread(file->data, 1, file->size, f); 81 if (bytes_read != file->size) { 82 printf("short read of \"%s\" (%ld bytes of %ld)\n", 83 filename, (long)bytes_read, (long)file->size); 84 free(file->data); 85 file->data = NULL; 86 return -1; 87 } 88 fclose(f); 89 90 // apply_patch[_check] functions are blind to randomization. Randomization 91 // is taken care of in [Undo]RetouchBinariesFn. If there is a mismatch 92 // within a file, this means the file is assumed "corrupt" for simplicity. 93 if (retouch_flag) { 94 int32_t desired_offset = 0; 95 if (retouch_mask_data(file->data, file->size, 96 &desired_offset, NULL) != RETOUCH_DATA_MATCHED) { 97 printf("error trying to mask retouch entries\n"); 98 free(file->data); 99 file->data = NULL; 100 return -1; 101 } 102 } 103 104 SHA(file->data, file->size, file->sha1); 105 return 0; 106 } 107 108 static size_t* size_array; 109 // comparison function for qsort()ing an int array of indexes into 110 // size_array[]. 111 static int compare_size_indices(const void* a, const void* b) { 112 int aa = *(int*)a; 113 int bb = *(int*)b; 114 if (size_array[aa] < size_array[bb]) { 115 return -1; 116 } else if (size_array[aa] > size_array[bb]) { 117 return 1; 118 } else { 119 return 0; 120 } 121 } 122 123 // Load the contents of an MTD or EMMC partition into the provided 124 // FileContents. filename should be a string of the form 125 // "MTD:<partition_name>:<size_1>:<sha1_1>:<size_2>:<sha1_2>:..." (or 126 // "EMMC:<partition_device>:..."). The smallest size_n bytes for 127 // which that prefix of the partition contents has the corresponding 128 // sha1 hash will be loaded. It is acceptable for a size value to be 129 // repeated with different sha1s. Will return 0 on success. 130 // 131 // This complexity is needed because if an OTA installation is 132 // interrupted, the partition might contain either the source or the 133 // target data, which might be of different lengths. We need to know 134 // the length in order to read from a partition (there is no 135 // "end-of-file" marker), so the caller must specify the possible 136 // lengths and the hash of the data, and we'll do the load expecting 137 // to find one of those hashes. 138 enum PartitionType { MTD, EMMC }; 139 140 static int LoadPartitionContents(const char* filename, FileContents* file) { 141 char* copy = strdup(filename); 142 const char* magic = strtok(copy, ":"); 143 144 enum PartitionType type; 145 146 if (strcmp(magic, "MTD") == 0) { 147 type = MTD; 148 } else if (strcmp(magic, "EMMC") == 0) { 149 type = EMMC; 150 } else { 151 printf("LoadPartitionContents called with bad filename (%s)\n", 152 filename); 153 return -1; 154 } 155 const char* partition = strtok(NULL, ":"); 156 157 int i; 158 int colons = 0; 159 for (i = 0; filename[i] != '\0'; ++i) { 160 if (filename[i] == ':') { 161 ++colons; 162 } 163 } 164 if (colons < 3 || colons%2 == 0) { 165 printf("LoadPartitionContents called with bad filename (%s)\n", 166 filename); 167 } 168 169 int pairs = (colons-1)/2; // # of (size,sha1) pairs in filename 170 int* index = malloc(pairs * sizeof(int)); 171 size_t* size = malloc(pairs * sizeof(size_t)); 172 char** sha1sum = malloc(pairs * sizeof(char*)); 173 174 for (i = 0; i < pairs; ++i) { 175 const char* size_str = strtok(NULL, ":"); 176 size[i] = strtol(size_str, NULL, 10); 177 if (size[i] == 0) { 178 printf("LoadPartitionContents called with bad size (%s)\n", filename); 179 return -1; 180 } 181 sha1sum[i] = strtok(NULL, ":"); 182 index[i] = i; 183 } 184 185 // sort the index[] array so it indexes the pairs in order of 186 // increasing size. 187 size_array = size; 188 qsort(index, pairs, sizeof(int), compare_size_indices); 189 190 MtdReadContext* ctx = NULL; 191 FILE* dev = NULL; 192 193 switch (type) { 194 case MTD: 195 if (!mtd_partitions_scanned) { 196 mtd_scan_partitions(); 197 mtd_partitions_scanned = 1; 198 } 199 200 const MtdPartition* mtd = mtd_find_partition_by_name(partition); 201 if (mtd == NULL) { 202 printf("mtd partition \"%s\" not found (loading %s)\n", 203 partition, filename); 204 return -1; 205 } 206 207 ctx = mtd_read_partition(mtd); 208 if (ctx == NULL) { 209 printf("failed to initialize read of mtd partition \"%s\"\n", 210 partition); 211 return -1; 212 } 213 break; 214 215 case EMMC: 216 dev = fopen(partition, "rb"); 217 if (dev == NULL) { 218 printf("failed to open emmc partition \"%s\": %s\n", 219 partition, strerror(errno)); 220 return -1; 221 } 222 } 223 224 SHA_CTX sha_ctx; 225 SHA_init(&sha_ctx); 226 uint8_t parsed_sha[SHA_DIGEST_SIZE]; 227 228 // allocate enough memory to hold the largest size. 229 file->data = malloc(size[index[pairs-1]]); 230 char* p = (char*)file->data; 231 file->size = 0; // # bytes read so far 232 233 for (i = 0; i < pairs; ++i) { 234 // Read enough additional bytes to get us up to the next size 235 // (again, we're trying the possibilities in order of increasing 236 // size). 237 size_t next = size[index[i]] - file->size; 238 size_t read = 0; 239 if (next > 0) { 240 switch (type) { 241 case MTD: 242 read = mtd_read_data(ctx, p, next); 243 break; 244 245 case EMMC: 246 read = fread(p, 1, next, dev); 247 break; 248 } 249 if (next != read) { 250 printf("short read (%d bytes of %d) for partition \"%s\"\n", 251 read, next, partition); 252 free(file->data); 253 file->data = NULL; 254 return -1; 255 } 256 SHA_update(&sha_ctx, p, read); 257 file->size += read; 258 } 259 260 // Duplicate the SHA context and finalize the duplicate so we can 261 // check it against this pair's expected hash. 262 SHA_CTX temp_ctx; 263 memcpy(&temp_ctx, &sha_ctx, sizeof(SHA_CTX)); 264 const uint8_t* sha_so_far = SHA_final(&temp_ctx); 265 266 if (ParseSha1(sha1sum[index[i]], parsed_sha) != 0) { 267 printf("failed to parse sha1 %s in %s\n", 268 sha1sum[index[i]], filename); 269 free(file->data); 270 file->data = NULL; 271 return -1; 272 } 273 274 if (memcmp(sha_so_far, parsed_sha, SHA_DIGEST_SIZE) == 0) { 275 // we have a match. stop reading the partition; we'll return 276 // the data we've read so far. 277 printf("partition read matched size %d sha %s\n", 278 size[index[i]], sha1sum[index[i]]); 279 break; 280 } 281 282 p += read; 283 } 284 285 switch (type) { 286 case MTD: 287 mtd_read_close(ctx); 288 break; 289 290 case EMMC: 291 fclose(dev); 292 break; 293 } 294 295 296 if (i == pairs) { 297 // Ran off the end of the list of (size,sha1) pairs without 298 // finding a match. 299 printf("contents of partition \"%s\" didn't match %s\n", 300 partition, filename); 301 free(file->data); 302 file->data = NULL; 303 return -1; 304 } 305 306 const uint8_t* sha_final = SHA_final(&sha_ctx); 307 for (i = 0; i < SHA_DIGEST_SIZE; ++i) { 308 file->sha1[i] = sha_final[i]; 309 } 310 311 // Fake some stat() info. 312 file->st.st_mode = 0644; 313 file->st.st_uid = 0; 314 file->st.st_gid = 0; 315 316 free(copy); 317 free(index); 318 free(size); 319 free(sha1sum); 320 321 return 0; 322 } 323 324 325 // Save the contents of the given FileContents object under the given 326 // filename. Return 0 on success. 327 int SaveFileContents(const char* filename, const FileContents* file) { 328 int fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, S_IRUSR | S_IWUSR); 329 if (fd < 0) { 330 printf("failed to open \"%s\" for write: %s\n", 331 filename, strerror(errno)); 332 return -1; 333 } 334 335 ssize_t bytes_written = FileSink(file->data, file->size, &fd); 336 if (bytes_written != file->size) { 337 printf("short write of \"%s\" (%ld bytes of %ld) (%s)\n", 338 filename, (long)bytes_written, (long)file->size, 339 strerror(errno)); 340 close(fd); 341 return -1; 342 } 343 fsync(fd); 344 close(fd); 345 346 if (chmod(filename, file->st.st_mode) != 0) { 347 printf("chmod of \"%s\" failed: %s\n", filename, strerror(errno)); 348 return -1; 349 } 350 if (chown(filename, file->st.st_uid, file->st.st_gid) != 0) { 351 printf("chown of \"%s\" failed: %s\n", filename, strerror(errno)); 352 return -1; 353 } 354 355 return 0; 356 } 357 358 // Write a memory buffer to 'target' partition, a string of the form 359 // "MTD:<partition>[:...]" or "EMMC:<partition_device>:". Return 0 on 360 // success. 361 int WriteToPartition(unsigned char* data, size_t len, 362 const char* target) { 363 char* copy = strdup(target); 364 const char* magic = strtok(copy, ":"); 365 366 enum PartitionType type; 367 if (strcmp(magic, "MTD") == 0) { 368 type = MTD; 369 } else if (strcmp(magic, "EMMC") == 0) { 370 type = EMMC; 371 } else { 372 printf("WriteToPartition called with bad target (%s)\n", target); 373 return -1; 374 } 375 const char* partition = strtok(NULL, ":"); 376 377 if (partition == NULL) { 378 printf("bad partition target name \"%s\"\n", target); 379 return -1; 380 } 381 382 switch (type) { 383 case MTD: 384 if (!mtd_partitions_scanned) { 385 mtd_scan_partitions(); 386 mtd_partitions_scanned = 1; 387 } 388 389 const MtdPartition* mtd = mtd_find_partition_by_name(partition); 390 if (mtd == NULL) { 391 printf("mtd partition \"%s\" not found for writing\n", 392 partition); 393 return -1; 394 } 395 396 MtdWriteContext* ctx = mtd_write_partition(mtd); 397 if (ctx == NULL) { 398 printf("failed to init mtd partition \"%s\" for writing\n", 399 partition); 400 return -1; 401 } 402 403 size_t written = mtd_write_data(ctx, (char*)data, len); 404 if (written != len) { 405 printf("only wrote %d of %d bytes to MTD %s\n", 406 written, len, partition); 407 mtd_write_close(ctx); 408 return -1; 409 } 410 411 if (mtd_erase_blocks(ctx, -1) < 0) { 412 printf("error finishing mtd write of %s\n", partition); 413 mtd_write_close(ctx); 414 return -1; 415 } 416 417 if (mtd_write_close(ctx)) { 418 printf("error closing mtd write of %s\n", partition); 419 return -1; 420 } 421 break; 422 423 case EMMC: 424 { 425 size_t start = 0; 426 int success = 0; 427 int fd = open(partition, O_RDWR | O_SYNC); 428 if (fd < 0) { 429 printf("failed to open %s: %s\n", partition, strerror(errno)); 430 return -1; 431 } 432 int attempt; 433 434 for (attempt = 0; attempt < 10; ++attempt) { 435 size_t next_sync = start + (1<<20); 436 printf("raw O_SYNC write %s attempt %d start at %d\n", partition, attempt+1, start); 437 lseek(fd, start, SEEK_SET); 438 while (start < len) { 439 size_t to_write = len - start; 440 if (to_write > 4096) to_write = 4096; 441 442 ssize_t written = write(fd, data+start, to_write); 443 if (written < 0) { 444 if (errno == EINTR) { 445 written = 0; 446 } else { 447 printf("failed write writing to %s (%s)\n", 448 partition, strerror(errno)); 449 return -1; 450 } 451 } 452 start += written; 453 if (start >= next_sync) { 454 fsync(fd); 455 next_sync = start + (1<<20); 456 } 457 } 458 fsync(fd); 459 460 // drop caches so our subsequent verification read 461 // won't just be reading the cache. 462 sync(); 463 int dc = open("/proc/sys/vm/drop_caches", O_WRONLY); 464 write(dc, "3\n", 2); 465 close(dc); 466 sleep(1); 467 printf(" caches dropped\n"); 468 469 // verify 470 lseek(fd, 0, SEEK_SET); 471 unsigned char buffer[4096]; 472 start = len; 473 size_t p; 474 for (p = 0; p < len; p += sizeof(buffer)) { 475 size_t to_read = len - p; 476 if (to_read > sizeof(buffer)) to_read = sizeof(buffer); 477 478 size_t so_far = 0; 479 while (so_far < to_read) { 480 ssize_t read_count = read(fd, buffer+so_far, to_read-so_far); 481 if (read_count < 0) { 482 if (errno == EINTR) { 483 read_count = 0; 484 } else { 485 printf("verify read error %s at %d: %s\n", 486 partition, p, strerror(errno)); 487 return -1; 488 } 489 } 490 if ((size_t)read_count < to_read) { 491 printf("short verify read %s at %d: %d %d %s\n", 492 partition, p, read_count, to_read, strerror(errno)); 493 } 494 so_far += read_count; 495 } 496 497 if (memcmp(buffer, data+p, to_read)) { 498 printf("verification failed starting at %d\n", p); 499 start = p; 500 break; 501 } 502 } 503 504 if (start == len) { 505 printf("verification read succeeded (attempt %d)\n", attempt+1); 506 success = true; 507 break; 508 } 509 510 sleep(2); 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 // hack: sync and sleep after closing in hopes of getting 523 // the data actually onto flash. 524 printf("sleeping after close\n"); 525 sync(); 526 sleep(5); 527 break; 528 } 529 } 530 531 free(copy); 532 return 0; 533 } 534 535 536 // Take a string 'str' of 40 hex digits and parse it into the 20 537 // byte array 'digest'. 'str' may contain only the digest or be of 538 // the form "<digest>:<anything>". Return 0 on success, -1 on any 539 // error. 540 int ParseSha1(const char* str, uint8_t* digest) { 541 int i; 542 const char* ps = str; 543 uint8_t* pd = digest; 544 for (i = 0; i < SHA_DIGEST_SIZE * 2; ++i, ++ps) { 545 int digit; 546 if (*ps >= '0' && *ps <= '9') { 547 digit = *ps - '0'; 548 } else if (*ps >= 'a' && *ps <= 'f') { 549 digit = *ps - 'a' + 10; 550 } else if (*ps >= 'A' && *ps <= 'F') { 551 digit = *ps - 'A' + 10; 552 } else { 553 return -1; 554 } 555 if (i % 2 == 0) { 556 *pd = digit << 4; 557 } else { 558 *pd |= digit; 559 ++pd; 560 } 561 } 562 if (*ps != '\0') return -1; 563 return 0; 564 } 565 566 // Search an array of sha1 strings for one matching the given sha1. 567 // Return the index of the match on success, or -1 if no match is 568 // found. 569 int FindMatchingPatch(uint8_t* sha1, char* const * const patch_sha1_str, 570 int num_patches) { 571 int i; 572 uint8_t patch_sha1[SHA_DIGEST_SIZE]; 573 for (i = 0; i < num_patches; ++i) { 574 if (ParseSha1(patch_sha1_str[i], patch_sha1) == 0 && 575 memcmp(patch_sha1, sha1, SHA_DIGEST_SIZE) == 0) { 576 return i; 577 } 578 } 579 return -1; 580 } 581 582 // Returns 0 if the contents of the file (argv[2]) or the cached file 583 // match any of the sha1's on the command line (argv[3:]). Returns 584 // nonzero otherwise. 585 int applypatch_check(const char* filename, 586 int num_patches, char** const patch_sha1_str) { 587 FileContents file; 588 file.data = NULL; 589 590 // It's okay to specify no sha1s; the check will pass if the 591 // LoadFileContents is successful. (Useful for reading 592 // partitions, where the filename encodes the sha1s; no need to 593 // check them twice.) 594 if (LoadFileContents(filename, &file, RETOUCH_DO_MASK) != 0 || 595 (num_patches > 0 && 596 FindMatchingPatch(file.sha1, patch_sha1_str, num_patches) < 0)) { 597 printf("file \"%s\" doesn't have any of expected " 598 "sha1 sums; checking cache\n", filename); 599 600 free(file.data); 601 file.data = NULL; 602 603 // If the source file is missing or corrupted, it might be because 604 // we were killed in the middle of patching it. A copy of it 605 // should have been made in CACHE_TEMP_SOURCE. If that file 606 // exists and matches the sha1 we're looking for, the check still 607 // passes. 608 609 if (LoadFileContents(CACHE_TEMP_SOURCE, &file, RETOUCH_DO_MASK) != 0) { 610 printf("failed to load cache file\n"); 611 return 1; 612 } 613 614 if (FindMatchingPatch(file.sha1, patch_sha1_str, num_patches) < 0) { 615 printf("cache bits don't match any sha1 for \"%s\"\n", filename); 616 free(file.data); 617 return 1; 618 } 619 } 620 621 free(file.data); 622 return 0; 623 } 624 625 int ShowLicenses() { 626 ShowBSDiffLicense(); 627 return 0; 628 } 629 630 ssize_t FileSink(unsigned char* data, ssize_t len, void* token) { 631 int fd = *(int *)token; 632 ssize_t done = 0; 633 ssize_t wrote; 634 while (done < (ssize_t) len) { 635 wrote = write(fd, data+done, len-done); 636 if (wrote <= 0) { 637 printf("error writing %d bytes: %s\n", (int)(len-done), strerror(errno)); 638 return done; 639 } 640 done += wrote; 641 } 642 return done; 643 } 644 645 typedef struct { 646 unsigned char* buffer; 647 ssize_t size; 648 ssize_t pos; 649 } MemorySinkInfo; 650 651 ssize_t MemorySink(unsigned char* data, ssize_t len, void* token) { 652 MemorySinkInfo* msi = (MemorySinkInfo*)token; 653 if (msi->size - msi->pos < len) { 654 return -1; 655 } 656 memcpy(msi->buffer + msi->pos, data, len); 657 msi->pos += len; 658 return len; 659 } 660 661 // Return the amount of free space (in bytes) on the filesystem 662 // containing filename. filename must exist. Return -1 on error. 663 size_t FreeSpaceForFile(const char* filename) { 664 struct statfs sf; 665 if (statfs(filename, &sf) != 0) { 666 printf("failed to statfs %s: %s\n", filename, strerror(errno)); 667 return -1; 668 } 669 return sf.f_bsize * sf.f_bfree; 670 } 671 672 int CacheSizeCheck(size_t bytes) { 673 if (MakeFreeSpaceOnCache(bytes) < 0) { 674 printf("unable to make %ld bytes available on /cache\n", (long)bytes); 675 return 1; 676 } else { 677 return 0; 678 } 679 } 680 681 static void print_short_sha1(const uint8_t sha1[SHA_DIGEST_SIZE]) { 682 int i; 683 const char* hex = "0123456789abcdef"; 684 for (i = 0; i < 4; ++i) { 685 putchar(hex[(sha1[i]>>4) & 0xf]); 686 putchar(hex[sha1[i] & 0xf]); 687 } 688 } 689 690 // This function applies binary patches to files in a way that is safe 691 // (the original file is not touched until we have the desired 692 // replacement for it) and idempotent (it's okay to run this program 693 // multiple times). 694 // 695 // - if the sha1 hash of <target_filename> is <target_sha1_string>, 696 // does nothing and exits successfully. 697 // 698 // - otherwise, if the sha1 hash of <source_filename> is one of the 699 // entries in <patch_sha1_str>, the corresponding patch from 700 // <patch_data> (which must be a VAL_BLOB) is applied to produce a 701 // new file (the type of patch is automatically detected from the 702 // blob daat). If that new file has sha1 hash <target_sha1_str>, 703 // moves it to replace <target_filename>, and exits successfully. 704 // Note that if <source_filename> and <target_filename> are not the 705 // same, <source_filename> is NOT deleted on success. 706 // <target_filename> may be the string "-" to mean "the same as 707 // source_filename". 708 // 709 // - otherwise, or if any error is encountered, exits with non-zero 710 // status. 711 // 712 // <source_filename> may refer to a partition to read the source data. 713 // See the comments for the LoadPartition Contents() function above 714 // for the format of such a filename. 715 716 int applypatch(const char* source_filename, 717 const char* target_filename, 718 const char* target_sha1_str, 719 size_t target_size, 720 int num_patches, 721 char** const patch_sha1_str, 722 Value** patch_data, 723 Value* bonus_data) { 724 printf("patch %s: ", source_filename); 725 726 if (target_filename[0] == '-' && 727 target_filename[1] == '\0') { 728 target_filename = source_filename; 729 } 730 731 uint8_t target_sha1[SHA_DIGEST_SIZE]; 732 if (ParseSha1(target_sha1_str, target_sha1) != 0) { 733 printf("failed to parse tgt-sha1 \"%s\"\n", target_sha1_str); 734 return 1; 735 } 736 737 FileContents copy_file; 738 FileContents source_file; 739 copy_file.data = NULL; 740 source_file.data = NULL; 741 const Value* source_patch_value = NULL; 742 const Value* copy_patch_value = NULL; 743 744 // We try to load the target file into the source_file object. 745 if (LoadFileContents(target_filename, &source_file, 746 RETOUCH_DO_MASK) == 0) { 747 if (memcmp(source_file.sha1, target_sha1, SHA_DIGEST_SIZE) == 0) { 748 // The early-exit case: the patch was already applied, this file 749 // has the desired hash, nothing for us to do. 750 printf("already "); 751 print_short_sha1(target_sha1); 752 putchar('\n'); 753 free(source_file.data); 754 return 0; 755 } 756 } 757 758 if (source_file.data == NULL || 759 (target_filename != source_filename && 760 strcmp(target_filename, source_filename) != 0)) { 761 // Need to load the source file: either we failed to load the 762 // target file, or we did but it's different from the source file. 763 free(source_file.data); 764 source_file.data = NULL; 765 LoadFileContents(source_filename, &source_file, 766 RETOUCH_DO_MASK); 767 } 768 769 if (source_file.data != NULL) { 770 int to_use = FindMatchingPatch(source_file.sha1, 771 patch_sha1_str, num_patches); 772 if (to_use >= 0) { 773 source_patch_value = patch_data[to_use]; 774 } 775 } 776 777 if (source_patch_value == NULL) { 778 free(source_file.data); 779 source_file.data = NULL; 780 printf("source file is bad; trying copy\n"); 781 782 if (LoadFileContents(CACHE_TEMP_SOURCE, ©_file, 783 RETOUCH_DO_MASK) < 0) { 784 // fail. 785 printf("failed to read copy file\n"); 786 return 1; 787 } 788 789 int to_use = FindMatchingPatch(copy_file.sha1, 790 patch_sha1_str, num_patches); 791 if (to_use >= 0) { 792 copy_patch_value = patch_data[to_use]; 793 } 794 795 if (copy_patch_value == NULL) { 796 // fail. 797 printf("copy file doesn't match source SHA-1s either\n"); 798 free(copy_file.data); 799 return 1; 800 } 801 } 802 803 int result = GenerateTarget(&source_file, source_patch_value, 804 ©_file, copy_patch_value, 805 source_filename, target_filename, 806 target_sha1, target_size, bonus_data); 807 free(source_file.data); 808 free(copy_file.data); 809 810 return result; 811 } 812 813 static int GenerateTarget(FileContents* source_file, 814 const Value* source_patch_value, 815 FileContents* copy_file, 816 const Value* copy_patch_value, 817 const char* source_filename, 818 const char* target_filename, 819 const uint8_t target_sha1[SHA_DIGEST_SIZE], 820 size_t target_size, 821 const Value* bonus_data) { 822 int retry = 1; 823 SHA_CTX ctx; 824 int output; 825 MemorySinkInfo msi; 826 FileContents* source_to_use; 827 char* outname; 828 int made_copy = 0; 829 830 // assume that target_filename (eg "/system/app/Foo.apk") is located 831 // on the same filesystem as its top-level directory ("/system"). 832 // We need something that exists for calling statfs(). 833 char target_fs[strlen(target_filename)+1]; 834 char* slash = strchr(target_filename+1, '/'); 835 if (slash != NULL) { 836 int count = slash - target_filename; 837 strncpy(target_fs, target_filename, count); 838 target_fs[count] = '\0'; 839 } else { 840 strcpy(target_fs, target_filename); 841 } 842 843 do { 844 // Is there enough room in the target filesystem to hold the patched 845 // file? 846 847 if (strncmp(target_filename, "MTD:", 4) == 0 || 848 strncmp(target_filename, "EMMC:", 5) == 0) { 849 // If the target is a partition, we're actually going to 850 // write the output to /tmp and then copy it to the 851 // partition. statfs() always returns 0 blocks free for 852 // /tmp, so instead we'll just assume that /tmp has enough 853 // space to hold the file. 854 855 // We still write the original source to cache, in case 856 // the partition write is interrupted. 857 if (MakeFreeSpaceOnCache(source_file->size) < 0) { 858 printf("not enough free space on /cache\n"); 859 return 1; 860 } 861 if (SaveFileContents(CACHE_TEMP_SOURCE, source_file) < 0) { 862 printf("failed to back up source file\n"); 863 return 1; 864 } 865 made_copy = 1; 866 retry = 0; 867 } else { 868 int enough_space = 0; 869 if (retry > 0) { 870 size_t free_space = FreeSpaceForFile(target_fs); 871 enough_space = 872 (free_space > (256 << 10)) && // 256k (two-block) minimum 873 (free_space > (target_size * 3 / 2)); // 50% margin of error 874 if (!enough_space) { 875 printf("target %ld bytes; free space %ld bytes; retry %d; enough %d\n", 876 (long)target_size, (long)free_space, retry, enough_space); 877 } 878 } 879 880 if (!enough_space) { 881 retry = 0; 882 } 883 884 if (!enough_space && source_patch_value != NULL) { 885 // Using the original source, but not enough free space. First 886 // copy the source file to cache, then delete it from the original 887 // location. 888 889 if (strncmp(source_filename, "MTD:", 4) == 0 || 890 strncmp(source_filename, "EMMC:", 5) == 0) { 891 // It's impossible to free space on the target filesystem by 892 // deleting the source if the source is a partition. If 893 // we're ever in a state where we need to do this, fail. 894 printf("not enough free space for target but source " 895 "is partition\n"); 896 return 1; 897 } 898 899 if (MakeFreeSpaceOnCache(source_file->size) < 0) { 900 printf("not enough free space on /cache\n"); 901 return 1; 902 } 903 904 if (SaveFileContents(CACHE_TEMP_SOURCE, source_file) < 0) { 905 printf("failed to back up source file\n"); 906 return 1; 907 } 908 made_copy = 1; 909 unlink(source_filename); 910 911 size_t free_space = FreeSpaceForFile(target_fs); 912 printf("(now %ld bytes free for target) ", (long)free_space); 913 } 914 } 915 916 const Value* patch; 917 if (source_patch_value != NULL) { 918 source_to_use = source_file; 919 patch = source_patch_value; 920 } else { 921 source_to_use = copy_file; 922 patch = copy_patch_value; 923 } 924 925 if (patch->type != VAL_BLOB) { 926 printf("patch is not a blob\n"); 927 return 1; 928 } 929 930 SinkFn sink = NULL; 931 void* token = NULL; 932 output = -1; 933 outname = NULL; 934 if (strncmp(target_filename, "MTD:", 4) == 0 || 935 strncmp(target_filename, "EMMC:", 5) == 0) { 936 // We store the decoded output in memory. 937 msi.buffer = malloc(target_size); 938 if (msi.buffer == NULL) { 939 printf("failed to alloc %ld bytes for output\n", 940 (long)target_size); 941 return 1; 942 } 943 msi.pos = 0; 944 msi.size = target_size; 945 sink = MemorySink; 946 token = &msi; 947 } else { 948 // We write the decoded output to "<tgt-file>.patch". 949 outname = (char*)malloc(strlen(target_filename) + 10); 950 strcpy(outname, target_filename); 951 strcat(outname, ".patch"); 952 953 output = open(outname, O_WRONLY | O_CREAT | O_TRUNC, S_IRUSR | S_IWUSR); 954 if (output < 0) { 955 printf("failed to open output file %s: %s\n", 956 outname, strerror(errno)); 957 return 1; 958 } 959 sink = FileSink; 960 token = &output; 961 } 962 963 char* header = patch->data; 964 ssize_t header_bytes_read = patch->size; 965 966 SHA_init(&ctx); 967 968 int result; 969 970 if (header_bytes_read >= 8 && 971 memcmp(header, "BSDIFF40", 8) == 0) { 972 result = ApplyBSDiffPatch(source_to_use->data, source_to_use->size, 973 patch, 0, sink, token, &ctx); 974 } else if (header_bytes_read >= 8 && 975 memcmp(header, "IMGDIFF2", 8) == 0) { 976 result = ApplyImagePatch(source_to_use->data, source_to_use->size, 977 patch, sink, token, &ctx, bonus_data); 978 } else { 979 printf("Unknown patch file format\n"); 980 return 1; 981 } 982 983 if (output >= 0) { 984 fsync(output); 985 close(output); 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
