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 int SaveFileContents(const char* filename, FileContents file); 34 static int LoadPartitionContents(const char* filename, FileContents* file); 35 int ParseSha1(const char* str, uint8_t* digest); 36 static ssize_t FileSink(unsigned char* data, ssize_t len, void* token); 37 38 static int mtd_partitions_scanned = 0; 39 40 // Read a file into memory; optionally (retouch_flag == RETOUCH_DO_MASK) mask 41 // the retouched entries back to their original value (such that SHA-1 checks 42 // don't fail due to randomization); store the file contents and associated 43 // metadata in *file. 44 // 45 // Return 0 on success. 46 int LoadFileContents(const char* filename, FileContents* file, 47 int retouch_flag) { 48 file->data = NULL; 49 50 // A special 'filename' beginning with "MTD:" or "EMMC:" means to 51 // load the contents of a partition. 52 if (strncmp(filename, "MTD:", 4) == 0 || 53 strncmp(filename, "EMMC:", 5) == 0) { 54 return LoadPartitionContents(filename, file); 55 } 56 57 if (stat(filename, &file->st) != 0) { 58 printf("failed to stat \"%s\": %s\n", filename, strerror(errno)); 59 return -1; 60 } 61 62 file->size = file->st.st_size; 63 file->data = malloc(file->size); 64 65 FILE* f = fopen(filename, "rb"); 66 if (f == NULL) { 67 printf("failed to open \"%s\": %s\n", filename, strerror(errno)); 68 free(file->data); 69 file->data = NULL; 70 return -1; 71 } 72 73 ssize_t bytes_read = fread(file->data, 1, file->size, f); 74 if (bytes_read != file->size) { 75 printf("short read of \"%s\" (%ld bytes of %ld)\n", 76 filename, (long)bytes_read, (long)file->size); 77 free(file->data); 78 file->data = NULL; 79 return -1; 80 } 81 fclose(f); 82 83 // apply_patch[_check] functions are blind to randomization. Randomization 84 // is taken care of in [Undo]RetouchBinariesFn. If there is a mismatch 85 // within a file, this means the file is assumed "corrupt" for simplicity. 86 if (retouch_flag) { 87 int32_t desired_offset = 0; 88 if (retouch_mask_data(file->data, file->size, 89 &desired_offset, NULL) != RETOUCH_DATA_MATCHED) { 90 printf("error trying to mask retouch entries\n"); 91 free(file->data); 92 file->data = NULL; 93 return -1; 94 } 95 } 96 97 SHA(file->data, file->size, file->sha1); 98 return 0; 99 } 100 101 static size_t* size_array; 102 // comparison function for qsort()ing an int array of indexes into 103 // size_array[]. 104 static int compare_size_indices(const void* a, const void* b) { 105 int aa = *(int*)a; 106 int bb = *(int*)b; 107 if (size_array[aa] < size_array[bb]) { 108 return -1; 109 } else if (size_array[aa] > size_array[bb]) { 110 return 1; 111 } else { 112 return 0; 113 } 114 } 115 116 void FreeFileContents(FileContents* file) { 117 if (file) free(file->data); 118 free(file); 119 } 120 121 // Load the contents of an MTD or EMMC partition into the provided 122 // FileContents. filename should be a string of the form 123 // "MTD:<partition_name>:<size_1>:<sha1_1>:<size_2>:<sha1_2>:..." (or 124 // "EMMC:<partition_device>:..."). The smallest size_n bytes for 125 // which that prefix of the partition contents has the corresponding 126 // sha1 hash will be loaded. It is acceptable for a size value to be 127 // repeated with different sha1s. Will return 0 on success. 128 // 129 // This complexity is needed because if an OTA installation is 130 // interrupted, the partition might contain either the source or the 131 // target data, which might be of different lengths. We need to know 132 // the length in order to read from a partition (there is no 133 // "end-of-file" marker), so the caller must specify the possible 134 // lengths and the hash of the data, and we'll do the load expecting 135 // to find one of those hashes. 136 enum PartitionType { MTD, EMMC }; 137 138 static int LoadPartitionContents(const char* filename, FileContents* file) { 139 char* copy = strdup(filename); 140 const char* magic = strtok(copy, ":"); 141 142 enum PartitionType type; 143 144 if (strcmp(magic, "MTD") == 0) { 145 type = MTD; 146 } else if (strcmp(magic, "EMMC") == 0) { 147 type = EMMC; 148 } else { 149 printf("LoadPartitionContents called with bad filename (%s)\n", 150 filename); 151 return -1; 152 } 153 const char* partition = strtok(NULL, ":"); 154 155 int i; 156 int colons = 0; 157 for (i = 0; filename[i] != '\0'; ++i) { 158 if (filename[i] == ':') { 159 ++colons; 160 } 161 } 162 if (colons < 3 || colons%2 == 0) { 163 printf("LoadPartitionContents called with bad filename (%s)\n", 164 filename); 165 } 166 167 int pairs = (colons-1)/2; // # of (size,sha1) pairs in filename 168 int* index = malloc(pairs * sizeof(int)); 169 size_t* size = malloc(pairs * sizeof(size_t)); 170 char** sha1sum = malloc(pairs * sizeof(char*)); 171 172 for (i = 0; i < pairs; ++i) { 173 const char* size_str = strtok(NULL, ":"); 174 size[i] = strtol(size_str, NULL, 10); 175 if (size[i] == 0) { 176 printf("LoadPartitionContents called with bad size (%s)\n", filename); 177 return -1; 178 } 179 sha1sum[i] = strtok(NULL, ":"); 180 index[i] = i; 181 } 182 183 // sort the index[] array so it indexes the pairs in order of 184 // increasing size. 185 size_array = size; 186 qsort(index, pairs, sizeof(int), compare_size_indices); 187 188 MtdReadContext* ctx = NULL; 189 FILE* dev = NULL; 190 191 switch (type) { 192 case MTD: 193 if (!mtd_partitions_scanned) { 194 mtd_scan_partitions(); 195 mtd_partitions_scanned = 1; 196 } 197 198 const MtdPartition* mtd = mtd_find_partition_by_name(partition); 199 if (mtd == NULL) { 200 printf("mtd partition \"%s\" not found (loading %s)\n", 201 partition, filename); 202 return -1; 203 } 204 205 ctx = mtd_read_partition(mtd); 206 if (ctx == NULL) { 207 printf("failed to initialize read of mtd partition \"%s\"\n", 208 partition); 209 return -1; 210 } 211 break; 212 213 case EMMC: 214 dev = fopen(partition, "rb"); 215 if (dev == NULL) { 216 printf("failed to open emmc partition \"%s\": %s\n", 217 partition, strerror(errno)); 218 return -1; 219 } 220 } 221 222 SHA_CTX sha_ctx; 223 SHA_init(&sha_ctx); 224 uint8_t parsed_sha[SHA_DIGEST_SIZE]; 225 226 // allocate enough memory to hold the largest size. 227 file->data = malloc(size[index[pairs-1]]); 228 char* p = (char*)file->data; 229 file->size = 0; // # bytes read so far 230 231 for (i = 0; i < pairs; ++i) { 232 // Read enough additional bytes to get us up to the next size 233 // (again, we're trying the possibilities in order of increasing 234 // size). 235 size_t next = size[index[i]] - file->size; 236 size_t read = 0; 237 if (next > 0) { 238 switch (type) { 239 case MTD: 240 read = mtd_read_data(ctx, p, next); 241 break; 242 243 case EMMC: 244 read = fread(p, 1, next, dev); 245 break; 246 } 247 if (next != read) { 248 printf("short read (%d bytes of %d) for partition \"%s\"\n", 249 read, next, partition); 250 free(file->data); 251 file->data = NULL; 252 return -1; 253 } 254 SHA_update(&sha_ctx, p, read); 255 file->size += read; 256 } 257 258 // Duplicate the SHA context and finalize the duplicate so we can 259 // check it against this pair's expected hash. 260 SHA_CTX temp_ctx; 261 memcpy(&temp_ctx, &sha_ctx, sizeof(SHA_CTX)); 262 const uint8_t* sha_so_far = SHA_final(&temp_ctx); 263 264 if (ParseSha1(sha1sum[index[i]], parsed_sha) != 0) { 265 printf("failed to parse sha1 %s in %s\n", 266 sha1sum[index[i]], filename); 267 free(file->data); 268 file->data = NULL; 269 return -1; 270 } 271 272 if (memcmp(sha_so_far, parsed_sha, SHA_DIGEST_SIZE) == 0) { 273 // we have a match. stop reading the partition; we'll return 274 // the data we've read so far. 275 printf("partition read matched size %d sha %s\n", 276 size[index[i]], sha1sum[index[i]]); 277 break; 278 } 279 280 p += read; 281 } 282 283 switch (type) { 284 case MTD: 285 mtd_read_close(ctx); 286 break; 287 288 case EMMC: 289 fclose(dev); 290 break; 291 } 292 293 294 if (i == pairs) { 295 // Ran off the end of the list of (size,sha1) pairs without 296 // finding a match. 297 printf("contents of partition \"%s\" didn't match %s\n", 298 partition, filename); 299 free(file->data); 300 file->data = NULL; 301 return -1; 302 } 303 304 const uint8_t* sha_final = SHA_final(&sha_ctx); 305 for (i = 0; i < SHA_DIGEST_SIZE; ++i) { 306 file->sha1[i] = sha_final[i]; 307 } 308 309 // Fake some stat() info. 310 file->st.st_mode = 0644; 311 file->st.st_uid = 0; 312 file->st.st_gid = 0; 313 314 free(copy); 315 free(index); 316 free(size); 317 free(sha1sum); 318 319 return 0; 320 } 321 322 323 // Save the contents of the given FileContents object under the given 324 // filename. Return 0 on success. 325 int SaveFileContents(const char* filename, FileContents file) { 326 int fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC); 327 if (fd < 0) { 328 printf("failed to open \"%s\" for write: %s\n", 329 filename, strerror(errno)); 330 return -1; 331 } 332 333 ssize_t bytes_written = FileSink(file.data, file.size, &fd); 334 if (bytes_written != file.size) { 335 printf("short write of \"%s\" (%ld bytes of %ld) (%s)\n", 336 filename, (long)bytes_written, (long)file.size, 337 strerror(errno)); 338 close(fd); 339 return -1; 340 } 341 fsync(fd); 342 close(fd); 343 344 if (chmod(filename, file.st.st_mode) != 0) { 345 printf("chmod of \"%s\" failed: %s\n", filename, strerror(errno)); 346 return -1; 347 } 348 if (chown(filename, file.st.st_uid, file.st.st_gid) != 0) { 349 printf("chown of \"%s\" failed: %s\n", filename, strerror(errno)); 350 return -1; 351 } 352 353 return 0; 354 } 355 356 // Write a memory buffer to 'target' partition, a string of the form 357 // "MTD:<partition>[:...]" or "EMMC:<partition_device>:". Return 0 on 358 // success. 359 int WriteToPartition(unsigned char* data, size_t len, 360 const char* target) { 361 char* copy = strdup(target); 362 const char* magic = strtok(copy, ":"); 363 364 enum PartitionType type; 365 if (strcmp(magic, "MTD") == 0) { 366 type = MTD; 367 } else if (strcmp(magic, "EMMC") == 0) { 368 type = EMMC; 369 } else { 370 printf("WriteToPartition called with bad target (%s)\n", target); 371 return -1; 372 } 373 const char* partition = strtok(NULL, ":"); 374 375 if (partition == NULL) { 376 printf("bad partition target name \"%s\"\n", target); 377 return -1; 378 } 379 380 switch (type) { 381 case MTD: 382 if (!mtd_partitions_scanned) { 383 mtd_scan_partitions(); 384 mtd_partitions_scanned = 1; 385 } 386 387 const MtdPartition* mtd = mtd_find_partition_by_name(partition); 388 if (mtd == NULL) { 389 printf("mtd partition \"%s\" not found for writing\n", 390 partition); 391 return -1; 392 } 393 394 MtdWriteContext* ctx = mtd_write_partition(mtd); 395 if (ctx == NULL) { 396 printf("failed to init mtd partition \"%s\" for writing\n", 397 partition); 398 return -1; 399 } 400 401 size_t written = mtd_write_data(ctx, (char*)data, len); 402 if (written != len) { 403 printf("only wrote %d of %d bytes to MTD %s\n", 404 written, len, partition); 405 mtd_write_close(ctx); 406 return -1; 407 } 408 409 if (mtd_erase_blocks(ctx, -1) < 0) { 410 printf("error finishing mtd write of %s\n", partition); 411 mtd_write_close(ctx); 412 return -1; 413 } 414 415 if (mtd_write_close(ctx)) { 416 printf("error closing mtd write of %s\n", partition); 417 return -1; 418 } 419 break; 420 421 case EMMC: 422 ; 423 FILE* f = fopen(partition, "wb"); 424 if (fwrite(data, 1, len, f) != len) { 425 printf("short write writing to %s (%s)\n", 426 partition, strerror(errno)); 427 return -1; 428 } 429 if (fclose(f) != 0) { 430 printf("error closing %s (%s)\n", partition, strerror(errno)); 431 return -1; 432 } 433 break; 434 } 435 436 free(copy); 437 return 0; 438 } 439 440 441 // Take a string 'str' of 40 hex digits and parse it into the 20 442 // byte array 'digest'. 'str' may contain only the digest or be of 443 // the form "<digest>:<anything>". Return 0 on success, -1 on any 444 // error. 445 int ParseSha1(const char* str, uint8_t* digest) { 446 int i; 447 const char* ps = str; 448 uint8_t* pd = digest; 449 for (i = 0; i < SHA_DIGEST_SIZE * 2; ++i, ++ps) { 450 int digit; 451 if (*ps >= '0' && *ps <= '9') { 452 digit = *ps - '0'; 453 } else if (*ps >= 'a' && *ps <= 'f') { 454 digit = *ps - 'a' + 10; 455 } else if (*ps >= 'A' && *ps <= 'F') { 456 digit = *ps - 'A' + 10; 457 } else { 458 return -1; 459 } 460 if (i % 2 == 0) { 461 *pd = digit << 4; 462 } else { 463 *pd |= digit; 464 ++pd; 465 } 466 } 467 if (*ps != '\0') return -1; 468 return 0; 469 } 470 471 // Search an array of sha1 strings for one matching the given sha1. 472 // Return the index of the match on success, or -1 if no match is 473 // found. 474 int FindMatchingPatch(uint8_t* sha1, char** const patch_sha1_str, 475 int num_patches) { 476 int i; 477 uint8_t patch_sha1[SHA_DIGEST_SIZE]; 478 for (i = 0; i < num_patches; ++i) { 479 if (ParseSha1(patch_sha1_str[i], patch_sha1) == 0 && 480 memcmp(patch_sha1, sha1, SHA_DIGEST_SIZE) == 0) { 481 return i; 482 } 483 } 484 return -1; 485 } 486 487 // Returns 0 if the contents of the file (argv[2]) or the cached file 488 // match any of the sha1's on the command line (argv[3:]). Returns 489 // nonzero otherwise. 490 int applypatch_check(const char* filename, 491 int num_patches, char** const patch_sha1_str) { 492 FileContents file; 493 file.data = NULL; 494 495 // It's okay to specify no sha1s; the check will pass if the 496 // LoadFileContents is successful. (Useful for reading 497 // partitions, where the filename encodes the sha1s; no need to 498 // check them twice.) 499 if (LoadFileContents(filename, &file, RETOUCH_DO_MASK) != 0 || 500 (num_patches > 0 && 501 FindMatchingPatch(file.sha1, patch_sha1_str, num_patches) < 0)) { 502 printf("file \"%s\" doesn't have any of expected " 503 "sha1 sums; checking cache\n", filename); 504 505 free(file.data); 506 507 // If the source file is missing or corrupted, it might be because 508 // we were killed in the middle of patching it. A copy of it 509 // should have been made in CACHE_TEMP_SOURCE. If that file 510 // exists and matches the sha1 we're looking for, the check still 511 // passes. 512 513 if (LoadFileContents(CACHE_TEMP_SOURCE, &file, RETOUCH_DO_MASK) != 0) { 514 printf("failed to load cache file\n"); 515 return 1; 516 } 517 518 if (FindMatchingPatch(file.sha1, patch_sha1_str, num_patches) < 0) { 519 printf("cache bits don't match any sha1 for \"%s\"\n", filename); 520 free(file.data); 521 return 1; 522 } 523 } 524 525 free(file.data); 526 return 0; 527 } 528 529 int ShowLicenses() { 530 ShowBSDiffLicense(); 531 return 0; 532 } 533 534 ssize_t FileSink(unsigned char* data, ssize_t len, void* token) { 535 int fd = *(int *)token; 536 ssize_t done = 0; 537 ssize_t wrote; 538 while (done < (ssize_t) len) { 539 wrote = write(fd, data+done, len-done); 540 if (wrote <= 0) { 541 printf("error writing %d bytes: %s\n", (int)(len-done), strerror(errno)); 542 return done; 543 } 544 done += wrote; 545 } 546 return done; 547 } 548 549 typedef struct { 550 unsigned char* buffer; 551 ssize_t size; 552 ssize_t pos; 553 } MemorySinkInfo; 554 555 ssize_t MemorySink(unsigned char* data, ssize_t len, void* token) { 556 MemorySinkInfo* msi = (MemorySinkInfo*)token; 557 if (msi->size - msi->pos < len) { 558 return -1; 559 } 560 memcpy(msi->buffer + msi->pos, data, len); 561 msi->pos += len; 562 return len; 563 } 564 565 // Return the amount of free space (in bytes) on the filesystem 566 // containing filename. filename must exist. Return -1 on error. 567 size_t FreeSpaceForFile(const char* filename) { 568 struct statfs sf; 569 if (statfs(filename, &sf) != 0) { 570 printf("failed to statfs %s: %s\n", filename, strerror(errno)); 571 return -1; 572 } 573 return sf.f_bsize * sf.f_bfree; 574 } 575 576 int CacheSizeCheck(size_t bytes) { 577 if (MakeFreeSpaceOnCache(bytes) < 0) { 578 printf("unable to make %ld bytes available on /cache\n", (long)bytes); 579 return 1; 580 } else { 581 return 0; 582 } 583 } 584 585 586 // This function applies binary patches to files in a way that is safe 587 // (the original file is not touched until we have the desired 588 // replacement for it) and idempotent (it's okay to run this program 589 // multiple times). 590 // 591 // - if the sha1 hash of <target_filename> is <target_sha1_string>, 592 // does nothing and exits successfully. 593 // 594 // - otherwise, if the sha1 hash of <source_filename> is one of the 595 // entries in <patch_sha1_str>, the corresponding patch from 596 // <patch_data> (which must be a VAL_BLOB) is applied to produce a 597 // new file (the type of patch is automatically detected from the 598 // blob daat). If that new file has sha1 hash <target_sha1_str>, 599 // moves it to replace <target_filename>, and exits successfully. 600 // Note that if <source_filename> and <target_filename> are not the 601 // same, <source_filename> is NOT deleted on success. 602 // <target_filename> may be the string "-" to mean "the same as 603 // source_filename". 604 // 605 // - otherwise, or if any error is encountered, exits with non-zero 606 // status. 607 // 608 // <source_filename> may refer to a partition to read the source data. 609 // See the comments for the LoadPartition Contents() function above 610 // for the format of such a filename. 611 612 int applypatch(const char* source_filename, 613 const char* target_filename, 614 const char* target_sha1_str, 615 size_t target_size, 616 int num_patches, 617 char** const patch_sha1_str, 618 Value** patch_data) { 619 printf("\napplying patch to %s\n", source_filename); 620 621 if (target_filename[0] == '-' && 622 target_filename[1] == '\0') { 623 target_filename = source_filename; 624 } 625 626 uint8_t target_sha1[SHA_DIGEST_SIZE]; 627 if (ParseSha1(target_sha1_str, target_sha1) != 0) { 628 printf("failed to parse tgt-sha1 \"%s\"\n", target_sha1_str); 629 return 1; 630 } 631 632 FileContents copy_file; 633 FileContents source_file; 634 const Value* source_patch_value = NULL; 635 const Value* copy_patch_value = NULL; 636 int made_copy = 0; 637 638 // We try to load the target file into the source_file object. 639 if (LoadFileContents(target_filename, &source_file, 640 RETOUCH_DO_MASK) == 0) { 641 if (memcmp(source_file.sha1, target_sha1, SHA_DIGEST_SIZE) == 0) { 642 // The early-exit case: the patch was already applied, this file 643 // has the desired hash, nothing for us to do. 644 printf("\"%s\" is already target; no patch needed\n", 645 target_filename); 646 return 0; 647 } 648 } 649 650 if (source_file.data == NULL || 651 (target_filename != source_filename && 652 strcmp(target_filename, source_filename) != 0)) { 653 // Need to load the source file: either we failed to load the 654 // target file, or we did but it's different from the source file. 655 free(source_file.data); 656 LoadFileContents(source_filename, &source_file, 657 RETOUCH_DO_MASK); 658 } 659 660 if (source_file.data != NULL) { 661 int to_use = FindMatchingPatch(source_file.sha1, 662 patch_sha1_str, num_patches); 663 if (to_use >= 0) { 664 source_patch_value = patch_data[to_use]; 665 } 666 } 667 668 if (source_patch_value == NULL) { 669 free(source_file.data); 670 printf("source file is bad; trying copy\n"); 671 672 if (LoadFileContents(CACHE_TEMP_SOURCE, ©_file, 673 RETOUCH_DO_MASK) < 0) { 674 // fail. 675 printf("failed to read copy file\n"); 676 return 1; 677 } 678 679 int to_use = FindMatchingPatch(copy_file.sha1, 680 patch_sha1_str, num_patches); 681 if (to_use >= 0) { 682 copy_patch_value = patch_data[to_use]; 683 } 684 685 if (copy_patch_value == NULL) { 686 // fail. 687 printf("copy file doesn't match source SHA-1s either\n"); 688 return 1; 689 } 690 } 691 692 int retry = 1; 693 SHA_CTX ctx; 694 int output; 695 MemorySinkInfo msi; 696 FileContents* source_to_use; 697 char* outname; 698 699 // assume that target_filename (eg "/system/app/Foo.apk") is located 700 // on the same filesystem as its top-level directory ("/system"). 701 // We need something that exists for calling statfs(). 702 char target_fs[strlen(target_filename)+1]; 703 char* slash = strchr(target_filename+1, '/'); 704 if (slash != NULL) { 705 int count = slash - target_filename; 706 strncpy(target_fs, target_filename, count); 707 target_fs[count] = '\0'; 708 } else { 709 strcpy(target_fs, target_filename); 710 } 711 712 do { 713 // Is there enough room in the target filesystem to hold the patched 714 // file? 715 716 if (strncmp(target_filename, "MTD:", 4) == 0 || 717 strncmp(target_filename, "EMMC:", 5) == 0) { 718 // If the target is a partition, we're actually going to 719 // write the output to /tmp and then copy it to the 720 // partition. statfs() always returns 0 blocks free for 721 // /tmp, so instead we'll just assume that /tmp has enough 722 // space to hold the file. 723 724 // We still write the original source to cache, in case 725 // the partition write is interrupted. 726 if (MakeFreeSpaceOnCache(source_file.size) < 0) { 727 printf("not enough free space on /cache\n"); 728 return 1; 729 } 730 if (SaveFileContents(CACHE_TEMP_SOURCE, source_file) < 0) { 731 printf("failed to back up source file\n"); 732 return 1; 733 } 734 made_copy = 1; 735 retry = 0; 736 } else { 737 int enough_space = 0; 738 if (retry > 0) { 739 size_t free_space = FreeSpaceForFile(target_fs); 740 enough_space = 741 (free_space > (256 << 10)) && // 256k (two-block) minimum 742 (free_space > (target_size * 3 / 2)); // 50% margin of error 743 printf("target %ld bytes; free space %ld bytes; retry %d; enough %d\n", 744 (long)target_size, (long)free_space, retry, enough_space); 745 } 746 747 if (!enough_space) { 748 retry = 0; 749 } 750 751 if (!enough_space && source_patch_value != NULL) { 752 // Using the original source, but not enough free space. First 753 // copy the source file to cache, then delete it from the original 754 // location. 755 756 if (strncmp(source_filename, "MTD:", 4) == 0 || 757 strncmp(source_filename, "EMMC:", 5) == 0) { 758 // It's impossible to free space on the target filesystem by 759 // deleting the source if the source is a partition. If 760 // we're ever in a state where we need to do this, fail. 761 printf("not enough free space for target but source " 762 "is partition\n"); 763 return 1; 764 } 765 766 if (MakeFreeSpaceOnCache(source_file.size) < 0) { 767 printf("not enough free space on /cache\n"); 768 return 1; 769 } 770 771 if (SaveFileContents(CACHE_TEMP_SOURCE, source_file) < 0) { 772 printf("failed to back up source file\n"); 773 return 1; 774 } 775 made_copy = 1; 776 unlink(source_filename); 777 778 size_t free_space = FreeSpaceForFile(target_fs); 779 printf("(now %ld bytes free for target)\n", (long)free_space); 780 } 781 } 782 783 const Value* patch; 784 if (source_patch_value != NULL) { 785 source_to_use = &source_file; 786 patch = source_patch_value; 787 } else { 788 source_to_use = ©_file; 789 patch = copy_patch_value; 790 } 791 792 if (patch->type != VAL_BLOB) { 793 printf("patch is not a blob\n"); 794 return 1; 795 } 796 797 SinkFn sink = NULL; 798 void* token = NULL; 799 output = -1; 800 outname = NULL; 801 if (strncmp(target_filename, "MTD:", 4) == 0 || 802 strncmp(target_filename, "EMMC:", 5) == 0) { 803 // We store the decoded output in memory. 804 msi.buffer = malloc(target_size); 805 if (msi.buffer == NULL) { 806 printf("failed to alloc %ld bytes for output\n", 807 (long)target_size); 808 return 1; 809 } 810 msi.pos = 0; 811 msi.size = target_size; 812 sink = MemorySink; 813 token = &msi; 814 } else { 815 // We write the decoded output to "<tgt-file>.patch". 816 outname = (char*)malloc(strlen(target_filename) + 10); 817 strcpy(outname, target_filename); 818 strcat(outname, ".patch"); 819 820 output = open(outname, O_WRONLY | O_CREAT | O_TRUNC); 821 if (output < 0) { 822 printf("failed to open output file %s: %s\n", 823 outname, strerror(errno)); 824 return 1; 825 } 826 sink = FileSink; 827 token = &output; 828 } 829 830 char* header = patch->data; 831 ssize_t header_bytes_read = patch->size; 832 833 SHA_init(&ctx); 834 835 int result; 836 837 if (header_bytes_read >= 8 && 838 memcmp(header, "BSDIFF40", 8) == 0) { 839 result = ApplyBSDiffPatch(source_to_use->data, source_to_use->size, 840 patch, 0, sink, token, &ctx); 841 } else if (header_bytes_read >= 8 && 842 memcmp(header, "IMGDIFF2", 8) == 0) { 843 result = ApplyImagePatch(source_to_use->data, source_to_use->size, 844 patch, sink, token, &ctx); 845 } else { 846 printf("Unknown patch file format\n"); 847 return 1; 848 } 849 850 if (output >= 0) { 851 fsync(output); 852 close(output); 853 } 854 855 if (result != 0) { 856 if (retry == 0) { 857 printf("applying patch failed\n"); 858 return result != 0; 859 } else { 860 printf("applying patch failed; retrying\n"); 861 } 862 if (outname != NULL) { 863 unlink(outname); 864 } 865 } else { 866 // succeeded; no need to retry 867 break; 868 } 869 } while (retry-- > 0); 870 871 const uint8_t* current_target_sha1 = SHA_final(&ctx); 872 if (memcmp(current_target_sha1, target_sha1, SHA_DIGEST_SIZE) != 0) { 873 printf("patch did not produce expected sha1\n"); 874 return 1; 875 } 876 877 if (output < 0) { 878 // Copy the temp file to the partition. 879 if (WriteToPartition(msi.buffer, msi.pos, target_filename) != 0) { 880 printf("write of patched data to %s failed\n", target_filename); 881 return 1; 882 } 883 free(msi.buffer); 884 } else { 885 // Give the .patch file the same owner, group, and mode of the 886 // original source file. 887 if (chmod(outname, source_to_use->st.st_mode) != 0) { 888 printf("chmod of \"%s\" failed: %s\n", outname, strerror(errno)); 889 return 1; 890 } 891 if (chown(outname, source_to_use->st.st_uid, 892 source_to_use->st.st_gid) != 0) { 893 printf("chown of \"%s\" failed: %s\n", outname, strerror(errno)); 894 return 1; 895 } 896 897 // Finally, rename the .patch file to replace the target file. 898 if (rename(outname, target_filename) != 0) { 899 printf("rename of .patch to \"%s\" failed: %s\n", 900 target_filename, strerror(errno)); 901 return 1; 902 } 903 } 904 905 // If this run of applypatch created the copy, and we're here, we 906 // can delete it. 907 if (made_copy) unlink(CACHE_TEMP_SOURCE); 908 909 // Success! 910 return 0; 911 } 912
