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 44 static int mtd_partitions_scanned = 0; 45 46 // Read a file into memory; optionally (retouch_flag == RETOUCH_DO_MASK) mask 47 // the retouched entries back to their original value (such that SHA-1 checks 48 // don't fail due to randomization); 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 int retouch_flag) { 54 file->data = NULL; 55 56 // A special 'filename' beginning with "MTD:" or "EMMC:" means to 57 // load the contents of a partition. 58 if (strncmp(filename, "MTD:", 4) == 0 || 59 strncmp(filename, "EMMC:", 5) == 0) { 60 return LoadPartitionContents(filename, file); 61 } 62 63 if (stat(filename, &file->st) != 0) { 64 printf("failed to stat \"%s\": %s\n", filename, strerror(errno)); 65 return -1; 66 } 67 68 file->size = file->st.st_size; 69 file->data = malloc(file->size); 70 71 FILE* f = fopen(filename, "rb"); 72 if (f == NULL) { 73 printf("failed to open \"%s\": %s\n", filename, strerror(errno)); 74 free(file->data); 75 file->data = NULL; 76 return -1; 77 } 78 79 ssize_t bytes_read = fread(file->data, 1, file->size, f); 80 if (bytes_read != file->size) { 81 printf("short read of \"%s\" (%ld bytes of %ld)\n", 82 filename, (long)bytes_read, (long)file->size); 83 free(file->data); 84 file->data = NULL; 85 return -1; 86 } 87 fclose(f); 88 89 // apply_patch[_check] functions are blind to randomization. Randomization 90 // is taken care of in [Undo]RetouchBinariesFn. If there is a mismatch 91 // within a file, this means the file is assumed "corrupt" for simplicity. 92 if (retouch_flag) { 93 int32_t desired_offset = 0; 94 if (retouch_mask_data(file->data, file->size, 95 &desired_offset, NULL) != RETOUCH_DATA_MATCHED) { 96 printf("error trying to mask retouch entries\n"); 97 free(file->data); 98 file->data = NULL; 99 return -1; 100 } 101 } 102 103 SHA(file->data, file->size, file->sha1); 104 return 0; 105 } 106 107 static size_t* size_array; 108 // comparison function for qsort()ing an int array of indexes into 109 // size_array[]. 110 static int compare_size_indices(const void* a, const void* b) { 111 int aa = *(int*)a; 112 int bb = *(int*)b; 113 if (size_array[aa] < size_array[bb]) { 114 return -1; 115 } else if (size_array[aa] > size_array[bb]) { 116 return 1; 117 } else { 118 return 0; 119 } 120 } 121 122 // Load the contents of an MTD or EMMC partition into the provided 123 // FileContents. filename should be a string of the form 124 // "MTD:<partition_name>:<size_1>:<sha1_1>:<size_2>:<sha1_2>:..." (or 125 // "EMMC:<partition_device>:..."). The smallest size_n bytes for 126 // which that prefix of the partition contents has the corresponding 127 // sha1 hash will be loaded. It is acceptable for a size value to be 128 // repeated with different sha1s. Will return 0 on success. 129 // 130 // This complexity is needed because if an OTA installation is 131 // interrupted, the partition might contain either the source or the 132 // target data, which might be of different lengths. We need to know 133 // the length in order to read from a partition (there is no 134 // "end-of-file" marker), so the caller must specify the possible 135 // lengths and the hash of the data, and we'll do the load expecting 136 // to find one of those hashes. 137 enum PartitionType { MTD, EMMC }; 138 139 static int LoadPartitionContents(const char* filename, FileContents* file) { 140 char* copy = strdup(filename); 141 const char* magic = strtok(copy, ":"); 142 143 enum PartitionType type; 144 145 if (strcmp(magic, "MTD") == 0) { 146 type = MTD; 147 } else if (strcmp(magic, "EMMC") == 0) { 148 type = EMMC; 149 } else { 150 printf("LoadPartitionContents called with bad filename (%s)\n", 151 filename); 152 return -1; 153 } 154 const char* partition = strtok(NULL, ":"); 155 156 int i; 157 int colons = 0; 158 for (i = 0; filename[i] != '\0'; ++i) { 159 if (filename[i] == ':') { 160 ++colons; 161 } 162 } 163 if (colons < 3 || colons%2 == 0) { 164 printf("LoadPartitionContents called with bad filename (%s)\n", 165 filename); 166 } 167 168 int pairs = (colons-1)/2; // # of (size,sha1) pairs in filename 169 int* index = malloc(pairs * sizeof(int)); 170 size_t* size = malloc(pairs * sizeof(size_t)); 171 char** sha1sum = malloc(pairs * sizeof(char*)); 172 173 for (i = 0; i < pairs; ++i) { 174 const char* size_str = strtok(NULL, ":"); 175 size[i] = strtol(size_str, NULL, 10); 176 if (size[i] == 0) { 177 printf("LoadPartitionContents called with bad size (%s)\n", filename); 178 return -1; 179 } 180 sha1sum[i] = strtok(NULL, ":"); 181 index[i] = i; 182 } 183 184 // sort the index[] array so it indexes the pairs in order of 185 // increasing size. 186 size_array = size; 187 qsort(index, pairs, sizeof(int), compare_size_indices); 188 189 MtdReadContext* ctx = NULL; 190 FILE* dev = NULL; 191 192 switch (type) { 193 case MTD: 194 if (!mtd_partitions_scanned) { 195 mtd_scan_partitions(); 196 mtd_partitions_scanned = 1; 197 } 198 199 const MtdPartition* mtd = mtd_find_partition_by_name(partition); 200 if (mtd == NULL) { 201 printf("mtd partition \"%s\" not found (loading %s)\n", 202 partition, filename); 203 return -1; 204 } 205 206 ctx = mtd_read_partition(mtd); 207 if (ctx == NULL) { 208 printf("failed to initialize read of mtd partition \"%s\"\n", 209 partition); 210 return -1; 211 } 212 break; 213 214 case EMMC: 215 dev = fopen(partition, "rb"); 216 if (dev == NULL) { 217 printf("failed to open emmc partition \"%s\": %s\n", 218 partition, strerror(errno)); 219 return -1; 220 } 221 } 222 223 SHA_CTX sha_ctx; 224 SHA_init(&sha_ctx); 225 uint8_t parsed_sha[SHA_DIGEST_SIZE]; 226 227 // allocate enough memory to hold the largest size. 228 file->data = malloc(size[index[pairs-1]]); 229 char* p = (char*)file->data; 230 file->size = 0; // # bytes read so far 231 232 for (i = 0; i < pairs; ++i) { 233 // Read enough additional bytes to get us up to the next size 234 // (again, we're trying the possibilities in order of increasing 235 // size). 236 size_t next = size[index[i]] - file->size; 237 size_t read = 0; 238 if (next > 0) { 239 switch (type) { 240 case MTD: 241 read = mtd_read_data(ctx, p, next); 242 break; 243 244 case EMMC: 245 read = fread(p, 1, next, dev); 246 break; 247 } 248 if (next != read) { 249 printf("short read (%d bytes of %d) for partition \"%s\"\n", 250 read, next, partition); 251 free(file->data); 252 file->data = NULL; 253 return -1; 254 } 255 SHA_update(&sha_ctx, p, read); 256 file->size += read; 257 } 258 259 // Duplicate the SHA context and finalize the duplicate so we can 260 // check it against this pair's expected hash. 261 SHA_CTX temp_ctx; 262 memcpy(&temp_ctx, &sha_ctx, sizeof(SHA_CTX)); 263 const uint8_t* sha_so_far = SHA_final(&temp_ctx); 264 265 if (ParseSha1(sha1sum[index[i]], parsed_sha) != 0) { 266 printf("failed to parse sha1 %s in %s\n", 267 sha1sum[index[i]], filename); 268 free(file->data); 269 file->data = NULL; 270 return -1; 271 } 272 273 if (memcmp(sha_so_far, parsed_sha, SHA_DIGEST_SIZE) == 0) { 274 // we have a match. stop reading the partition; we'll return 275 // the data we've read so far. 276 printf("partition read matched size %d sha %s\n", 277 size[index[i]], sha1sum[index[i]]); 278 break; 279 } 280 281 p += read; 282 } 283 284 switch (type) { 285 case MTD: 286 mtd_read_close(ctx); 287 break; 288 289 case EMMC: 290 fclose(dev); 291 break; 292 } 293 294 295 if (i == pairs) { 296 // Ran off the end of the list of (size,sha1) pairs without 297 // finding a match. 298 printf("contents of partition \"%s\" didn't match %s\n", 299 partition, filename); 300 free(file->data); 301 file->data = NULL; 302 return -1; 303 } 304 305 const uint8_t* sha_final = SHA_final(&sha_ctx); 306 for (i = 0; i < SHA_DIGEST_SIZE; ++i) { 307 file->sha1[i] = sha_final[i]; 308 } 309 310 // Fake some stat() info. 311 file->st.st_mode = 0644; 312 file->st.st_uid = 0; 313 file->st.st_gid = 0; 314 315 free(copy); 316 free(index); 317 free(size); 318 free(sha1sum); 319 320 return 0; 321 } 322 323 324 // Save the contents of the given FileContents object under the given 325 // filename. Return 0 on success. 326 int SaveFileContents(const char* filename, const FileContents* file) { 327 int fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC); 328 if (fd < 0) { 329 printf("failed to open \"%s\" for write: %s\n", 330 filename, strerror(errno)); 331 return -1; 332 } 333 334 ssize_t bytes_written = FileSink(file->data, file->size, &fd); 335 if (bytes_written != file->size) { 336 printf("short write of \"%s\" (%ld bytes of %ld) (%s)\n", 337 filename, (long)bytes_written, (long)file->size, 338 strerror(errno)); 339 close(fd); 340 return -1; 341 } 342 fsync(fd); 343 close(fd); 344 345 if (chmod(filename, file->st.st_mode) != 0) { 346 printf("chmod of \"%s\" failed: %s\n", filename, strerror(errno)); 347 return -1; 348 } 349 if (chown(filename, file->st.st_uid, file->st.st_gid) != 0) { 350 printf("chown of \"%s\" failed: %s\n", filename, strerror(errno)); 351 return -1; 352 } 353 354 return 0; 355 } 356 357 // Write a memory buffer to 'target' partition, a string of the form 358 // "MTD:<partition>[:...]" or "EMMC:<partition_device>:". Return 0 on 359 // success. 360 int WriteToPartition(unsigned char* data, size_t len, 361 const char* target) { 362 char* copy = strdup(target); 363 const char* magic = strtok(copy, ":"); 364 365 enum PartitionType type; 366 if (strcmp(magic, "MTD") == 0) { 367 type = MTD; 368 } else if (strcmp(magic, "EMMC") == 0) { 369 type = EMMC; 370 } else { 371 printf("WriteToPartition called with bad target (%s)\n", target); 372 return -1; 373 } 374 const char* partition = strtok(NULL, ":"); 375 376 if (partition == NULL) { 377 printf("bad partition target name \"%s\"\n", target); 378 return -1; 379 } 380 381 switch (type) { 382 case MTD: 383 if (!mtd_partitions_scanned) { 384 mtd_scan_partitions(); 385 mtd_partitions_scanned = 1; 386 } 387 388 const MtdPartition* mtd = mtd_find_partition_by_name(partition); 389 if (mtd == NULL) { 390 printf("mtd partition \"%s\" not found for writing\n", 391 partition); 392 return -1; 393 } 394 395 MtdWriteContext* ctx = mtd_write_partition(mtd); 396 if (ctx == NULL) { 397 printf("failed to init mtd partition \"%s\" for writing\n", 398 partition); 399 return -1; 400 } 401 402 size_t written = mtd_write_data(ctx, (char*)data, len); 403 if (written != len) { 404 printf("only wrote %d of %d bytes to MTD %s\n", 405 written, len, partition); 406 mtd_write_close(ctx); 407 return -1; 408 } 409 410 if (mtd_erase_blocks(ctx, -1) < 0) { 411 printf("error finishing mtd write of %s\n", partition); 412 mtd_write_close(ctx); 413 return -1; 414 } 415 416 if (mtd_write_close(ctx)) { 417 printf("error closing mtd write of %s\n", partition); 418 return -1; 419 } 420 break; 421 422 case EMMC: 423 ; 424 FILE* f = fopen(partition, "wb"); 425 if (fwrite(data, 1, len, f) != len) { 426 printf("short write writing to %s (%s)\n", 427 partition, strerror(errno)); 428 return -1; 429 } 430 if (fclose(f) != 0) { 431 printf("error closing %s (%s)\n", partition, strerror(errno)); 432 return -1; 433 } 434 break; 435 } 436 437 free(copy); 438 return 0; 439 } 440 441 442 // Take a string 'str' of 40 hex digits and parse it into the 20 443 // byte array 'digest'. 'str' may contain only the digest or be of 444 // the form "<digest>:<anything>". Return 0 on success, -1 on any 445 // error. 446 int ParseSha1(const char* str, uint8_t* digest) { 447 int i; 448 const char* ps = str; 449 uint8_t* pd = digest; 450 for (i = 0; i < SHA_DIGEST_SIZE * 2; ++i, ++ps) { 451 int digit; 452 if (*ps >= '0' && *ps <= '9') { 453 digit = *ps - '0'; 454 } else if (*ps >= 'a' && *ps <= 'f') { 455 digit = *ps - 'a' + 10; 456 } else if (*ps >= 'A' && *ps <= 'F') { 457 digit = *ps - 'A' + 10; 458 } else { 459 return -1; 460 } 461 if (i % 2 == 0) { 462 *pd = digit << 4; 463 } else { 464 *pd |= digit; 465 ++pd; 466 } 467 } 468 if (*ps != '\0') return -1; 469 return 0; 470 } 471 472 // Search an array of sha1 strings for one matching the given sha1. 473 // Return the index of the match on success, or -1 if no match is 474 // found. 475 int FindMatchingPatch(uint8_t* sha1, const char** patch_sha1_str, 476 int num_patches) { 477 int i; 478 uint8_t patch_sha1[SHA_DIGEST_SIZE]; 479 for (i = 0; i < num_patches; ++i) { 480 if (ParseSha1(patch_sha1_str[i], patch_sha1) == 0 && 481 memcmp(patch_sha1, sha1, SHA_DIGEST_SIZE) == 0) { 482 return i; 483 } 484 } 485 return -1; 486 } 487 488 // Returns 0 if the contents of the file (argv[2]) or the cached file 489 // match any of the sha1's on the command line (argv[3:]). Returns 490 // nonzero otherwise. 491 int applypatch_check(const char* filename, 492 int num_patches, char** const patch_sha1_str) { 493 FileContents file; 494 file.data = NULL; 495 496 // It's okay to specify no sha1s; the check will pass if the 497 // LoadFileContents is successful. (Useful for reading 498 // partitions, where the filename encodes the sha1s; no need to 499 // check them twice.) 500 if (LoadFileContents(filename, &file, RETOUCH_DO_MASK) != 0 || 501 (num_patches > 0 && 502 FindMatchingPatch(file.sha1, patch_sha1_str, num_patches) < 0)) { 503 printf("file \"%s\" doesn't have any of expected " 504 "sha1 sums; checking cache\n", filename); 505 506 free(file.data); 507 file.data = NULL; 508 509 // If the source file is missing or corrupted, it might be because 510 // we were killed in the middle of patching it. A copy of it 511 // should have been made in CACHE_TEMP_SOURCE. If that file 512 // exists and matches the sha1 we're looking for, the check still 513 // passes. 514 515 if (LoadFileContents(CACHE_TEMP_SOURCE, &file, RETOUCH_DO_MASK) != 0) { 516 printf("failed to load cache file\n"); 517 return 1; 518 } 519 520 if (FindMatchingPatch(file.sha1, patch_sha1_str, num_patches) < 0) { 521 printf("cache bits don't match any sha1 for \"%s\"\n", filename); 522 free(file.data); 523 return 1; 524 } 525 } 526 527 free(file.data); 528 return 0; 529 } 530 531 int ShowLicenses() { 532 ShowBSDiffLicense(); 533 return 0; 534 } 535 536 ssize_t FileSink(unsigned char* data, ssize_t len, void* token) { 537 int fd = *(int *)token; 538 ssize_t done = 0; 539 ssize_t wrote; 540 while (done < (ssize_t) len) { 541 wrote = write(fd, data+done, len-done); 542 if (wrote <= 0) { 543 printf("error writing %d bytes: %s\n", (int)(len-done), strerror(errno)); 544 return done; 545 } 546 done += wrote; 547 } 548 return done; 549 } 550 551 typedef struct { 552 unsigned char* buffer; 553 ssize_t size; 554 ssize_t pos; 555 } MemorySinkInfo; 556 557 ssize_t MemorySink(unsigned char* data, ssize_t len, void* token) { 558 MemorySinkInfo* msi = (MemorySinkInfo*)token; 559 if (msi->size - msi->pos < len) { 560 return -1; 561 } 562 memcpy(msi->buffer + msi->pos, data, len); 563 msi->pos += len; 564 return len; 565 } 566 567 // Return the amount of free space (in bytes) on the filesystem 568 // containing filename. filename must exist. Return -1 on error. 569 size_t FreeSpaceForFile(const char* filename) { 570 struct statfs sf; 571 if (statfs(filename, &sf) != 0) { 572 printf("failed to statfs %s: %s\n", filename, strerror(errno)); 573 return -1; 574 } 575 return sf.f_bsize * sf.f_bfree; 576 } 577 578 int CacheSizeCheck(size_t bytes) { 579 if (MakeFreeSpaceOnCache(bytes) < 0) { 580 printf("unable to make %ld bytes available on /cache\n", (long)bytes); 581 return 1; 582 } else { 583 return 0; 584 } 585 } 586 587 588 // This function applies binary patches to files in a way that is safe 589 // (the original file is not touched until we have the desired 590 // replacement for it) and idempotent (it's okay to run this program 591 // multiple times). 592 // 593 // - if the sha1 hash of <target_filename> is <target_sha1_string>, 594 // does nothing and exits successfully. 595 // 596 // - otherwise, if the sha1 hash of <source_filename> is one of the 597 // entries in <patch_sha1_str>, the corresponding patch from 598 // <patch_data> (which must be a VAL_BLOB) is applied to produce a 599 // new file (the type of patch is automatically detected from the 600 // blob daat). If that new file has sha1 hash <target_sha1_str>, 601 // moves it to replace <target_filename>, and exits successfully. 602 // Note that if <source_filename> and <target_filename> are not the 603 // same, <source_filename> is NOT deleted on success. 604 // <target_filename> may be the string "-" to mean "the same as 605 // source_filename". 606 // 607 // - otherwise, or if any error is encountered, exits with non-zero 608 // status. 609 // 610 // <source_filename> may refer to a partition to read the source data. 611 // See the comments for the LoadPartition Contents() function above 612 // for the format of such a filename. 613 614 int applypatch(const char* source_filename, 615 const char* target_filename, 616 const char* target_sha1_str, 617 size_t target_size, 618 int num_patches, 619 char** const patch_sha1_str, 620 Value** patch_data) { 621 printf("\napplying patch to %s\n", source_filename); 622 623 if (target_filename[0] == '-' && 624 target_filename[1] == '\0') { 625 target_filename = source_filename; 626 } 627 628 uint8_t target_sha1[SHA_DIGEST_SIZE]; 629 if (ParseSha1(target_sha1_str, target_sha1) != 0) { 630 printf("failed to parse tgt-sha1 \"%s\"\n", target_sha1_str); 631 return 1; 632 } 633 634 FileContents copy_file; 635 FileContents source_file; 636 copy_file.data = NULL; 637 source_file.data = NULL; 638 const Value* source_patch_value = NULL; 639 const Value* copy_patch_value = NULL; 640 641 // We try to load the target file into the source_file object. 642 if (LoadFileContents(target_filename, &source_file, 643 RETOUCH_DO_MASK) == 0) { 644 if (memcmp(source_file.sha1, target_sha1, SHA_DIGEST_SIZE) == 0) { 645 // The early-exit case: the patch was already applied, this file 646 // has the desired hash, nothing for us to do. 647 printf("\"%s\" is already target; no patch needed\n", 648 target_filename); 649 free(source_file.data); 650 return 0; 651 } 652 } 653 654 if (source_file.data == NULL || 655 (target_filename != source_filename && 656 strcmp(target_filename, source_filename) != 0)) { 657 // Need to load the source file: either we failed to load the 658 // target file, or we did but it's different from the source file. 659 free(source_file.data); 660 source_file.data = NULL; 661 LoadFileContents(source_filename, &source_file, 662 RETOUCH_DO_MASK); 663 } 664 665 if (source_file.data != NULL) { 666 int to_use = FindMatchingPatch(source_file.sha1, 667 patch_sha1_str, num_patches); 668 if (to_use >= 0) { 669 source_patch_value = patch_data[to_use]; 670 } 671 } 672 673 if (source_patch_value == NULL) { 674 free(source_file.data); 675 source_file.data = NULL; 676 printf("source file is bad; trying copy\n"); 677 678 if (LoadFileContents(CACHE_TEMP_SOURCE, ©_file, 679 RETOUCH_DO_MASK) < 0) { 680 // fail. 681 printf("failed to read copy file\n"); 682 return 1; 683 } 684 685 int to_use = FindMatchingPatch(copy_file.sha1, 686 patch_sha1_str, num_patches); 687 if (to_use >= 0) { 688 copy_patch_value = patch_data[to_use]; 689 } 690 691 if (copy_patch_value == NULL) { 692 // fail. 693 printf("copy file doesn't match source SHA-1s either\n"); 694 free(copy_file.data); 695 return 1; 696 } 697 } 698 699 int result = GenerateTarget(&source_file, source_patch_value, 700 ©_file, copy_patch_value, 701 source_filename, target_filename, 702 target_sha1, target_size); 703 free(source_file.data); 704 free(copy_file.data); 705 706 return result; 707 } 708 709 static int GenerateTarget(FileContents* source_file, 710 const Value* source_patch_value, 711 FileContents* copy_file, 712 const Value* copy_patch_value, 713 const char* source_filename, 714 const char* target_filename, 715 const uint8_t target_sha1[SHA_DIGEST_SIZE], 716 size_t target_size) { 717 int retry = 1; 718 SHA_CTX ctx; 719 int output; 720 MemorySinkInfo msi; 721 FileContents* source_to_use; 722 char* outname; 723 int made_copy = 0; 724 725 // assume that target_filename (eg "/system/app/Foo.apk") is located 726 // on the same filesystem as its top-level directory ("/system"). 727 // We need something that exists for calling statfs(). 728 char target_fs[strlen(target_filename)+1]; 729 char* slash = strchr(target_filename+1, '/'); 730 if (slash != NULL) { 731 int count = slash - target_filename; 732 strncpy(target_fs, target_filename, count); 733 target_fs[count] = '\0'; 734 } else { 735 strcpy(target_fs, target_filename); 736 } 737 738 do { 739 // Is there enough room in the target filesystem to hold the patched 740 // file? 741 742 if (strncmp(target_filename, "MTD:", 4) == 0 || 743 strncmp(target_filename, "EMMC:", 5) == 0) { 744 // If the target is a partition, we're actually going to 745 // write the output to /tmp and then copy it to the 746 // partition. statfs() always returns 0 blocks free for 747 // /tmp, so instead we'll just assume that /tmp has enough 748 // space to hold the file. 749 750 // We still write the original source to cache, in case 751 // the partition write is interrupted. 752 if (MakeFreeSpaceOnCache(source_file->size) < 0) { 753 printf("not enough free space on /cache\n"); 754 return 1; 755 } 756 if (SaveFileContents(CACHE_TEMP_SOURCE, source_file) < 0) { 757 printf("failed to back up source file\n"); 758 return 1; 759 } 760 made_copy = 1; 761 retry = 0; 762 } else { 763 int enough_space = 0; 764 if (retry > 0) { 765 size_t free_space = FreeSpaceForFile(target_fs); 766 enough_space = 767 (free_space > (256 << 10)) && // 256k (two-block) minimum 768 (free_space > (target_size * 3 / 2)); // 50% margin of error 769 printf("target %ld bytes; free space %ld bytes; retry %d; enough %d\n", 770 (long)target_size, (long)free_space, retry, enough_space); 771 } 772 773 if (!enough_space) { 774 retry = 0; 775 } 776 777 if (!enough_space && source_patch_value != NULL) { 778 // Using the original source, but not enough free space. First 779 // copy the source file to cache, then delete it from the original 780 // location. 781 782 if (strncmp(source_filename, "MTD:", 4) == 0 || 783 strncmp(source_filename, "EMMC:", 5) == 0) { 784 // It's impossible to free space on the target filesystem by 785 // deleting the source if the source is a partition. If 786 // we're ever in a state where we need to do this, fail. 787 printf("not enough free space for target but source " 788 "is partition\n"); 789 return 1; 790 } 791 792 if (MakeFreeSpaceOnCache(source_file->size) < 0) { 793 printf("not enough free space on /cache\n"); 794 return 1; 795 } 796 797 if (SaveFileContents(CACHE_TEMP_SOURCE, source_file) < 0) { 798 printf("failed to back up source file\n"); 799 return 1; 800 } 801 made_copy = 1; 802 unlink(source_filename); 803 804 size_t free_space = FreeSpaceForFile(target_fs); 805 printf("(now %ld bytes free for target)\n", (long)free_space); 806 } 807 } 808 809 const Value* patch; 810 if (source_patch_value != NULL) { 811 source_to_use = source_file; 812 patch = source_patch_value; 813 } else { 814 source_to_use = copy_file; 815 patch = copy_patch_value; 816 } 817 818 if (patch->type != VAL_BLOB) { 819 printf("patch is not a blob\n"); 820 return 1; 821 } 822 823 SinkFn sink = NULL; 824 void* token = NULL; 825 output = -1; 826 outname = NULL; 827 if (strncmp(target_filename, "MTD:", 4) == 0 || 828 strncmp(target_filename, "EMMC:", 5) == 0) { 829 // We store the decoded output in memory. 830 msi.buffer = malloc(target_size); 831 if (msi.buffer == NULL) { 832 printf("failed to alloc %ld bytes for output\n", 833 (long)target_size); 834 return 1; 835 } 836 msi.pos = 0; 837 msi.size = target_size; 838 sink = MemorySink; 839 token = &msi; 840 } else { 841 // We write the decoded output to "<tgt-file>.patch". 842 outname = (char*)malloc(strlen(target_filename) + 10); 843 strcpy(outname, target_filename); 844 strcat(outname, ".patch"); 845 846 output = open(outname, O_WRONLY | O_CREAT | O_TRUNC); 847 if (output < 0) { 848 printf("failed to open output file %s: %s\n", 849 outname, strerror(errno)); 850 return 1; 851 } 852 sink = FileSink; 853 token = &output; 854 } 855 856 char* header = patch->data; 857 ssize_t header_bytes_read = patch->size; 858 859 SHA_init(&ctx); 860 861 int result; 862 863 if (header_bytes_read >= 8 && 864 memcmp(header, "BSDIFF40", 8) == 0) { 865 result = ApplyBSDiffPatch(source_to_use->data, source_to_use->size, 866 patch, 0, sink, token, &ctx); 867 } else if (header_bytes_read >= 8 && 868 memcmp(header, "IMGDIFF2", 8) == 0) { 869 result = ApplyImagePatch(source_to_use->data, source_to_use->size, 870 patch, sink, token, &ctx); 871 } else { 872 printf("Unknown patch file format\n"); 873 return 1; 874 } 875 876 if (output >= 0) { 877 fsync(output); 878 close(output); 879 } 880 881 if (result != 0) { 882 if (retry == 0) { 883 printf("applying patch failed\n"); 884 return result != 0; 885 } else { 886 printf("applying patch failed; retrying\n"); 887 } 888 if (outname != NULL) { 889 unlink(outname); 890 } 891 } else { 892 // succeeded; no need to retry 893 break; 894 } 895 } while (retry-- > 0); 896 897 const uint8_t* current_target_sha1 = SHA_final(&ctx); 898 if (memcmp(current_target_sha1, target_sha1, SHA_DIGEST_SIZE) != 0) { 899 printf("patch did not produce expected sha1\n"); 900 return 1; 901 } 902 903 if (output < 0) { 904 // Copy the temp file to the partition. 905 if (WriteToPartition(msi.buffer, msi.pos, target_filename) != 0) { 906 printf("write of patched data to %s failed\n", target_filename); 907 return 1; 908 } 909 free(msi.buffer); 910 } else { 911 // Give the .patch file the same owner, group, and mode of the 912 // original source file. 913 if (chmod(outname, source_to_use->st.st_mode) != 0) { 914 printf("chmod of \"%s\" failed: %s\n", outname, strerror(errno)); 915 return 1; 916 } 917 if (chown(outname, source_to_use->st.st_uid, 918 source_to_use->st.st_gid) != 0) { 919 printf("chown of \"%s\" failed: %s\n", outname, strerror(errno)); 920 return 1; 921 } 922 923 // Finally, rename the .patch file to replace the target file. 924 if (rename(outname, target_filename) != 0) { 925 printf("rename of .patch to \"%s\" failed: %s\n", 926 target_filename, strerror(errno)); 927 return 1; 928 } 929 } 930 931 // If this run of applypatch created the copy, and we're here, we 932 // can delete it. 933 if (made_copy) unlink(CACHE_TEMP_SOURCE); 934 935 // Success! 936 return 0; 937 } 938
