1/* 2 * GIT - The information manager from hell 3 * 4 * Copyright (C) Linus Torvalds, 2005 5 */ 6#define NO_THE_INDEX_COMPATIBILITY_MACROS 7#include "cache.h" 8#include "cache-tree.h" 9#include "refs.h" 10#include "dir.h" 11 12/* Index extensions. 13 * 14 * The first letter should be 'A'..'Z' for extensions that are not 15 * necessary for a correct operation (i.e. optimization data). 16 * When new extensions are added that _needs_ to be understood in 17 * order to correctly interpret the index file, pick character that 18 * is outside the range, to cause the reader to abort. 19 */ 20 21#define CACHE_EXT(s) ( (s[0]<<24)|(s[1]<<16)|(s[2]<<8)|(s[3]) ) 22#define CACHE_EXT_TREE 0x54524545 /* "TREE" */ 23 24struct index_state the_index; 25 26/* 27 * This only updates the "non-critical" parts of the directory 28 * cache, ie the parts that aren't tracked by GIT, and only used 29 * to validate the cache. 30 */ 31void fill_stat_cache_info(struct cache_entry *ce, struct stat *st) 32{ 33 ce->ce_ctime.sec = htonl(st->st_ctime); 34 ce->ce_mtime.sec = htonl(st->st_mtime); 35#ifdef USE_NSEC 36 ce->ce_ctime.nsec = htonl(st->st_ctim.tv_nsec); 37 ce->ce_mtime.nsec = htonl(st->st_mtim.tv_nsec); 38#endif 39 ce->ce_dev = htonl(st->st_dev); 40 ce->ce_ino = htonl(st->st_ino); 41 ce->ce_uid = htonl(st->st_uid); 42 ce->ce_gid = htonl(st->st_gid); 43 ce->ce_size = htonl(st->st_size); 44 45 if (assume_unchanged) 46 ce->ce_flags |= htons(CE_VALID); 47} 48 49static int ce_compare_data(struct cache_entry *ce, struct stat *st) 50{ 51 int match = -1; 52 int fd = open(ce->name, O_RDONLY); 53 54 if (fd >= 0) { 55 unsigned char sha1[20]; 56 if (!index_fd(sha1, fd, st, 0, OBJ_BLOB, ce->name)) 57 match = hashcmp(sha1, ce->sha1); 58 /* index_fd() closed the file descriptor already */ 59 } 60 return match; 61} 62 63static int ce_compare_link(struct cache_entry *ce, size_t expected_size) 64{ 65 int match = -1; 66 char *target; 67 void *buffer; 68 unsigned long size; 69 enum object_type type; 70 int len; 71 72 target = xmalloc(expected_size); 73 len = readlink(ce->name, target, expected_size); 74 if (len != expected_size) { 75 free(target); 76 return -1; 77 } 78 buffer = read_sha1_file(ce->sha1, &type, &size); 79 if (!buffer) { 80 free(target); 81 return -1; 82 } 83 if (size == expected_size) 84 match = memcmp(buffer, target, size); 85 free(buffer); 86 free(target); 87 return match; 88} 89 90static int ce_compare_gitlink(struct cache_entry *ce) 91{ 92 unsigned char sha1[20]; 93 94 /* 95 * We don't actually require that the .git directory 96 * under GITLINK directory be a valid git directory. It 97 * might even be missing (in case nobody populated that 98 * sub-project). 99 * 100 * If so, we consider it always to match. 101 */ 102 if (resolve_gitlink_ref(ce->name, "HEAD", sha1) < 0) 103 return 0; 104 return hashcmp(sha1, ce->sha1); 105} 106 107static int ce_modified_check_fs(struct cache_entry *ce, struct stat *st) 108{ 109 switch (st->st_mode & S_IFMT) { 110 case S_IFREG: 111 if (ce_compare_data(ce, st)) 112 return DATA_CHANGED; 113 break; 114 case S_IFLNK: 115 if (ce_compare_link(ce, xsize_t(st->st_size))) 116 return DATA_CHANGED; 117 break; 118 case S_IFDIR: 119 if (S_ISGITLINK(ntohl(ce->ce_mode))) 120 return 0; 121 default: 122 return TYPE_CHANGED; 123 } 124 return 0; 125} 126 127static int ce_match_stat_basic(struct cache_entry *ce, struct stat *st) 128{ 129 unsigned int changed = 0; 130 131 switch (ntohl(ce->ce_mode) & S_IFMT) { 132 case S_IFREG: 133 changed |= !S_ISREG(st->st_mode) ? TYPE_CHANGED : 0; 134 /* We consider only the owner x bit to be relevant for 135 * "mode changes" 136 */ 137 if (trust_executable_bit && 138 (0100 & (ntohl(ce->ce_mode) ^ st->st_mode))) 139 changed |= MODE_CHANGED; 140 break; 141 case S_IFLNK: 142 if (!S_ISLNK(st->st_mode) && 143 (has_symlinks || !S_ISREG(st->st_mode))) 144 changed |= TYPE_CHANGED; 145 break; 146 case S_IFGITLINK: 147 if (!S_ISDIR(st->st_mode)) 148 changed |= TYPE_CHANGED; 149 else if (ce_compare_gitlink(ce)) 150 changed |= DATA_CHANGED; 151 return changed; 152 case 0: /* Special case: unmerged file in index */ 153 return MODE_CHANGED | DATA_CHANGED | TYPE_CHANGED; 154 default: 155 die("internal error: ce_mode is %o", ntohl(ce->ce_mode)); 156 } 157 if (ce->ce_mtime.sec != htonl(st->st_mtime)) 158 changed |= MTIME_CHANGED; 159 if (ce->ce_ctime.sec != htonl(st->st_ctime)) 160 changed |= CTIME_CHANGED; 161 162#ifdef USE_NSEC 163 /* 164 * nsec seems unreliable - not all filesystems support it, so 165 * as long as it is in the inode cache you get right nsec 166 * but after it gets flushed, you get zero nsec. 167 */ 168 if (ce->ce_mtime.nsec != htonl(st->st_mtim.tv_nsec)) 169 changed |= MTIME_CHANGED; 170 if (ce->ce_ctime.nsec != htonl(st->st_ctim.tv_nsec)) 171 changed |= CTIME_CHANGED; 172#endif 173 174 if (ce->ce_uid != htonl(st->st_uid) || 175 ce->ce_gid != htonl(st->st_gid)) 176 changed |= OWNER_CHANGED; 177 if (ce->ce_ino != htonl(st->st_ino)) 178 changed |= INODE_CHANGED; 179 180#ifdef USE_STDEV 181 /* 182 * st_dev breaks on network filesystems where different 183 * clients will have different views of what "device" 184 * the filesystem is on 185 */ 186 if (ce->ce_dev != htonl(st->st_dev)) 187 changed |= INODE_CHANGED; 188#endif 189 190 if (ce->ce_size != htonl(st->st_size)) 191 changed |= DATA_CHANGED; 192 193 return changed; 194} 195 196int ie_match_stat(struct index_state *istate, 197 struct cache_entry *ce, struct stat *st, 198 unsigned int options) 199{ 200 unsigned int changed; 201 int ignore_valid = options & CE_MATCH_IGNORE_VALID; 202 int assume_racy_is_modified = options & CE_MATCH_RACY_IS_DIRTY; 203 204 /* 205 * If it's marked as always valid in the index, it's 206 * valid whatever the checked-out copy says. 207 */ 208 if (!ignore_valid && (ce->ce_flags & htons(CE_VALID))) 209 return 0; 210 211 changed = ce_match_stat_basic(ce, st); 212 213 /* 214 * Within 1 second of this sequence: 215 * echo xyzzy >file && git-update-index --add file 216 * running this command: 217 * echo frotz >file 218 * would give a falsely clean cache entry. The mtime and 219 * length match the cache, and other stat fields do not change. 220 * 221 * We could detect this at update-index time (the cache entry 222 * being registered/updated records the same time as "now") 223 * and delay the return from git-update-index, but that would 224 * effectively mean we can make at most one commit per second, 225 * which is not acceptable. Instead, we check cache entries 226 * whose mtime are the same as the index file timestamp more 227 * carefully than others. 228 */ 229 if (!changed && 230 istate->timestamp && 231 istate->timestamp <= ntohl(ce->ce_mtime.sec)) { 232 if (assume_racy_is_modified) 233 changed |= DATA_CHANGED; 234 else 235 changed |= ce_modified_check_fs(ce, st); 236 } 237 238 return changed; 239} 240 241int ie_modified(struct index_state *istate, 242 struct cache_entry *ce, struct stat *st, unsigned int options) 243{ 244 int changed, changed_fs; 245 246 changed = ie_match_stat(istate, ce, st, options); 247 if (!changed) 248 return 0; 249 /* 250 * If the mode or type has changed, there's no point in trying 251 * to refresh the entry - it's not going to match 252 */ 253 if (changed & (MODE_CHANGED | TYPE_CHANGED)) 254 return changed; 255 256 /* Immediately after read-tree or update-index --cacheinfo, 257 * the length field is zero. For other cases the ce_size 258 * should match the SHA1 recorded in the index entry. 259 */ 260 if ((changed & DATA_CHANGED) && ce->ce_size != htonl(0)) 261 return changed; 262 263 changed_fs = ce_modified_check_fs(ce, st); 264 if (changed_fs) 265 return changed | changed_fs; 266 return 0; 267} 268 269int base_name_compare(const char *name1, int len1, int mode1, 270 const char *name2, int len2, int mode2) 271{ 272 unsigned char c1, c2; 273 int len = len1 < len2 ? len1 : len2; 274 int cmp; 275 276 cmp = memcmp(name1, name2, len); 277 if (cmp) 278 return cmp; 279 c1 = name1[len]; 280 c2 = name2[len]; 281 if (!c1 && S_ISDIR(mode1)) 282 c1 = '/'; 283 if (!c2 && S_ISDIR(mode2)) 284 c2 = '/'; 285 return (c1 < c2) ? -1 : (c1 > c2) ? 1 : 0; 286} 287 288int cache_name_compare(const char *name1, int flags1, const char *name2, int flags2) 289{ 290 int len1 = flags1 & CE_NAMEMASK; 291 int len2 = flags2 & CE_NAMEMASK; 292 int len = len1 < len2 ? len1 : len2; 293 int cmp; 294 295 cmp = memcmp(name1, name2, len); 296 if (cmp) 297 return cmp; 298 if (len1 < len2) 299 return -1; 300 if (len1 > len2) 301 return 1; 302 303 /* Compare stages */ 304 flags1 &= CE_STAGEMASK; 305 flags2 &= CE_STAGEMASK; 306 307 if (flags1 < flags2) 308 return -1; 309 if (flags1 > flags2) 310 return 1; 311 return 0; 312} 313 314int index_name_pos(struct index_state *istate, const char *name, int namelen) 315{ 316 int first, last; 317 318 first = 0; 319 last = istate->cache_nr; 320 while (last > first) { 321 int next = (last + first) >> 1; 322 struct cache_entry *ce = istate->cache[next]; 323 int cmp = cache_name_compare(name, namelen, ce->name, ntohs(ce->ce_flags)); 324 if (!cmp) 325 return next; 326 if (cmp < 0) { 327 last = next; 328 continue; 329 } 330 first = next+1; 331 } 332 return -first-1; 333} 334 335/* Remove entry, return true if there are more entries to go.. */ 336int remove_index_entry_at(struct index_state *istate, int pos) 337{ 338 istate->cache_changed = 1; 339 istate->cache_nr--; 340 if (pos >= istate->cache_nr) 341 return 0; 342 memmove(istate->cache + pos, 343 istate->cache + pos + 1, 344 (istate->cache_nr - pos) * sizeof(struct cache_entry *)); 345 return 1; 346} 347 348int remove_file_from_index(struct index_state *istate, const char *path) 349{ 350 int pos = index_name_pos(istate, path, strlen(path)); 351 if (pos < 0) 352 pos = -pos-1; 353 cache_tree_invalidate_path(istate->cache_tree, path); 354 while (pos < istate->cache_nr && !strcmp(istate->cache[pos]->name, path)) 355 remove_index_entry_at(istate, pos); 356 return 0; 357} 358 359static int compare_name(struct cache_entry *ce, const char *path, int namelen) 360{ 361 return namelen != ce_namelen(ce) || memcmp(path, ce->name, namelen); 362} 363 364static int index_name_pos_also_unmerged(struct index_state *istate, 365 const char *path, int namelen) 366{ 367 int pos = index_name_pos(istate, path, namelen); 368 struct cache_entry *ce; 369 370 if (pos >= 0) 371 return pos; 372 373 /* maybe unmerged? */ 374 pos = -1 - pos; 375 if (pos >= istate->cache_nr || 376 compare_name((ce = istate->cache[pos]), path, namelen)) 377 return -1; 378 379 /* order of preference: stage 2, 1, 3 */ 380 if (ce_stage(ce) == 1 && pos + 1 < istate->cache_nr && 381 ce_stage((ce = istate->cache[pos + 1])) == 2 && 382 !compare_name(ce, path, namelen)) 383 pos++; 384 return pos; 385} 386 387int add_file_to_index(struct index_state *istate, const char *path, int verbose) 388{ 389 int size, namelen, pos; 390 struct stat st; 391 struct cache_entry *ce; 392 unsigned ce_option = CE_MATCH_IGNORE_VALID|CE_MATCH_RACY_IS_DIRTY; 393 394 if (lstat(path, &st)) 395 die("%s: unable to stat (%s)", path, strerror(errno)); 396 397 if (!S_ISREG(st.st_mode) && !S_ISLNK(st.st_mode) && !S_ISDIR(st.st_mode)) 398 die("%s: can only add regular files, symbolic links or git-directories", path); 399 400 namelen = strlen(path); 401 if (S_ISDIR(st.st_mode)) { 402 while (namelen && path[namelen-1] == '/') 403 namelen--; 404 } 405 size = cache_entry_size(namelen); 406 ce = xcalloc(1, size); 407 memcpy(ce->name, path, namelen); 408 ce->ce_flags = htons(namelen); 409 fill_stat_cache_info(ce, &st); 410 411 if (trust_executable_bit && has_symlinks) 412 ce->ce_mode = create_ce_mode(st.st_mode); 413 else { 414 /* If there is an existing entry, pick the mode bits and type 415 * from it, otherwise assume unexecutable regular file. 416 */ 417 struct cache_entry *ent; 418 int pos = index_name_pos_also_unmerged(istate, path, namelen); 419 420 ent = (0 <= pos) ? istate->cache[pos] : NULL; 421 ce->ce_mode = ce_mode_from_stat(ent, st.st_mode); 422 } 423 424 pos = index_name_pos(istate, ce->name, namelen); 425 if (0 <= pos && 426 !ce_stage(istate->cache[pos]) && 427 !ie_match_stat(istate, istate->cache[pos], &st, ce_option)) { 428 /* Nothing changed, really */ 429 free(ce); 430 return 0; 431 } 432 433 if (index_path(ce->sha1, path, &st, 1)) 434 die("unable to index file %s", path); 435 if (add_index_entry(istate, ce, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE)) 436 die("unable to add %s to index",path); 437 if (verbose) 438 printf("add '%s'\n", path); 439 return 0; 440} 441 442struct cache_entry *make_cache_entry(unsigned int mode, 443 const unsigned char *sha1, const char *path, int stage, 444 int refresh) 445{ 446 int size, len; 447 struct cache_entry *ce; 448 449 if (!verify_path(path)) 450 return NULL; 451 452 len = strlen(path); 453 size = cache_entry_size(len); 454 ce = xcalloc(1, size); 455 456 hashcpy(ce->sha1, sha1); 457 memcpy(ce->name, path, len); 458 ce->ce_flags = create_ce_flags(len, stage); 459 ce->ce_mode = create_ce_mode(mode); 460 461 if (refresh) 462 return refresh_cache_entry(ce, 0); 463 464 return ce; 465} 466 467int ce_same_name(struct cache_entry *a, struct cache_entry *b) 468{ 469 int len = ce_namelen(a); 470 return ce_namelen(b) == len && !memcmp(a->name, b->name, len); 471} 472 473int ce_path_match(const struct cache_entry *ce, const char **pathspec) 474{ 475 const char *match, *name; 476 int len; 477 478 if (!pathspec) 479 return 1; 480 481 len = ce_namelen(ce); 482 name = ce->name; 483 while ((match = *pathspec++) != NULL) { 484 int matchlen = strlen(match); 485 if (matchlen > len) 486 continue; 487 if (memcmp(name, match, matchlen)) 488 continue; 489 if (matchlen && name[matchlen-1] == '/') 490 return 1; 491 if (name[matchlen] == '/' || !name[matchlen]) 492 return 1; 493 if (!matchlen) 494 return 1; 495 } 496 return 0; 497} 498 499/* 500 * We fundamentally don't like some paths: we don't want 501 * dot or dot-dot anywhere, and for obvious reasons don't 502 * want to recurse into ".git" either. 503 * 504 * Also, we don't want double slashes or slashes at the 505 * end that can make pathnames ambiguous. 506 */ 507static int verify_dotfile(const char *rest) 508{ 509 /* 510 * The first character was '.', but that 511 * has already been discarded, we now test 512 * the rest. 513 */ 514 switch (*rest) { 515 /* "." is not allowed */ 516 case '\0': case '/': 517 return 0; 518 519 /* 520 * ".git" followed by NUL or slash is bad. This 521 * shares the path end test with the ".." case. 522 */ 523 case 'g': 524 if (rest[1] != 'i') 525 break; 526 if (rest[2] != 't') 527 break; 528 rest += 2; 529 /* fallthrough */ 530 case '.': 531 if (rest[1] == '\0' || rest[1] == '/') 532 return 0; 533 } 534 return 1; 535} 536 537int verify_path(const char *path) 538{ 539 char c; 540 541 goto inside; 542 for (;;) { 543 if (!c) 544 return 1; 545 if (c == '/') { 546inside: 547 c = *path++; 548 switch (c) { 549 default: 550 continue; 551 case '/': case '\0': 552 break; 553 case '.': 554 if (verify_dotfile(path)) 555 continue; 556 } 557 return 0; 558 } 559 c = *path++; 560 } 561} 562 563/* 564 * Do we have another file that has the beginning components being a 565 * proper superset of the name we're trying to add? 566 */ 567static int has_file_name(struct index_state *istate, 568 const struct cache_entry *ce, int pos, int ok_to_replace) 569{ 570 int retval = 0; 571 int len = ce_namelen(ce); 572 int stage = ce_stage(ce); 573 const char *name = ce->name; 574 575 while (pos < istate->cache_nr) { 576 struct cache_entry *p = istate->cache[pos++]; 577 578 if (len >= ce_namelen(p)) 579 break; 580 if (memcmp(name, p->name, len)) 581 break; 582 if (ce_stage(p) != stage) 583 continue; 584 if (p->name[len] != '/') 585 continue; 586 if (!ce_stage(p) && !p->ce_mode) 587 continue; 588 retval = -1; 589 if (!ok_to_replace) 590 break; 591 remove_index_entry_at(istate, --pos); 592 } 593 return retval; 594} 595 596/* 597 * Do we have another file with a pathname that is a proper 598 * subset of the name we're trying to add? 599 */ 600static int has_dir_name(struct index_state *istate, 601 const struct cache_entry *ce, int pos, int ok_to_replace) 602{ 603 int retval = 0; 604 int stage = ce_stage(ce); 605 const char *name = ce->name; 606 const char *slash = name + ce_namelen(ce); 607 608 for (;;) { 609 int len; 610 611 for (;;) { 612 if (*--slash == '/') 613 break; 614 if (slash <= ce->name) 615 return retval; 616 } 617 len = slash - name; 618 619 pos = index_name_pos(istate, name, ntohs(create_ce_flags(len, stage))); 620 if (pos >= 0) { 621 /* 622 * Found one, but not so fast. This could 623 * be a marker that says "I was here, but 624 * I am being removed". Such an entry is 625 * not a part of the resulting tree, and 626 * it is Ok to have a directory at the same 627 * path. 628 */ 629 if (stage || istate->cache[pos]->ce_mode) { 630 retval = -1; 631 if (!ok_to_replace) 632 break; 633 remove_index_entry_at(istate, pos); 634 continue; 635 } 636 } 637 else 638 pos = -pos-1; 639 640 /* 641 * Trivial optimization: if we find an entry that 642 * already matches the sub-directory, then we know 643 * we're ok, and we can exit. 644 */ 645 while (pos < istate->cache_nr) { 646 struct cache_entry *p = istate->cache[pos]; 647 if ((ce_namelen(p) <= len) || 648 (p->name[len] != '/') || 649 memcmp(p->name, name, len)) 650 break; /* not our subdirectory */ 651 if (ce_stage(p) == stage && (stage || p->ce_mode)) 652 /* p is at the same stage as our entry, and 653 * is a subdirectory of what we are looking 654 * at, so we cannot have conflicts at our 655 * level or anything shorter. 656 */ 657 return retval; 658 pos++; 659 } 660 } 661 return retval; 662} 663 664/* We may be in a situation where we already have path/file and path 665 * is being added, or we already have path and path/file is being 666 * added. Either one would result in a nonsense tree that has path 667 * twice when git-write-tree tries to write it out. Prevent it. 668 * 669 * If ok-to-replace is specified, we remove the conflicting entries 670 * from the cache so the caller should recompute the insert position. 671 * When this happens, we return non-zero. 672 */ 673static int check_file_directory_conflict(struct index_state *istate, 674 const struct cache_entry *ce, 675 int pos, int ok_to_replace) 676{ 677 int retval; 678 679 /* 680 * When ce is an "I am going away" entry, we allow it to be added 681 */ 682 if (!ce_stage(ce) && !ce->ce_mode) 683 return 0; 684 685 /* 686 * We check if the path is a sub-path of a subsequent pathname 687 * first, since removing those will not change the position 688 * in the array. 689 */ 690 retval = has_file_name(istate, ce, pos, ok_to_replace); 691 692 /* 693 * Then check if the path might have a clashing sub-directory 694 * before it. 695 */ 696 return retval + has_dir_name(istate, ce, pos, ok_to_replace); 697} 698 699static int add_index_entry_with_check(struct index_state *istate, struct cache_entry *ce, int option) 700{ 701 int pos; 702 int ok_to_add = option & ADD_CACHE_OK_TO_ADD; 703 int ok_to_replace = option & ADD_CACHE_OK_TO_REPLACE; 704 int skip_df_check = option & ADD_CACHE_SKIP_DFCHECK; 705 706 cache_tree_invalidate_path(istate->cache_tree, ce->name); 707 pos = index_name_pos(istate, ce->name, ntohs(ce->ce_flags)); 708 709 /* existing match? Just replace it. */ 710 if (pos >= 0) { 711 istate->cache_changed = 1; 712 istate->cache[pos] = ce; 713 return 0; 714 } 715 pos = -pos-1; 716 717 /* 718 * Inserting a merged entry ("stage 0") into the index 719 * will always replace all non-merged entries.. 720 */ 721 if (pos < istate->cache_nr && ce_stage(ce) == 0) { 722 while (ce_same_name(istate->cache[pos], ce)) { 723 ok_to_add = 1; 724 if (!remove_index_entry_at(istate, pos)) 725 break; 726 } 727 } 728 729 if (!ok_to_add) 730 return -1; 731 if (!verify_path(ce->name)) 732 return -1; 733 734 if (!skip_df_check && 735 check_file_directory_conflict(istate, ce, pos, ok_to_replace)) { 736 if (!ok_to_replace) 737 return error("'%s' appears as both a file and as a directory", 738 ce->name); 739 pos = index_name_pos(istate, ce->name, ntohs(ce->ce_flags)); 740 pos = -pos-1; 741 } 742 return pos + 1; 743} 744 745int add_index_entry(struct index_state *istate, struct cache_entry *ce, int option) 746{ 747 int pos; 748 749 if (option & ADD_CACHE_JUST_APPEND) 750 pos = istate->cache_nr; 751 else { 752 int ret; 753 ret = add_index_entry_with_check(istate, ce, option); 754 if (ret <= 0) 755 return ret; 756 pos = ret - 1; 757 } 758 759 /* Make sure the array is big enough .. */ 760 if (istate->cache_nr == istate->cache_alloc) { 761 istate->cache_alloc = alloc_nr(istate->cache_alloc); 762 istate->cache = xrealloc(istate->cache, 763 istate->cache_alloc * sizeof(struct cache_entry *)); 764 } 765 766 /* Add it in.. */ 767 istate->cache_nr++; 768 if (istate->cache_nr > pos + 1) 769 memmove(istate->cache + pos + 1, 770 istate->cache + pos, 771 (istate->cache_nr - pos - 1) * sizeof(ce)); 772 istate->cache[pos] = ce; 773 istate->cache_changed = 1; 774 return 0; 775} 776 777/* 778 * "refresh" does not calculate a new sha1 file or bring the 779 * cache up-to-date for mode/content changes. But what it 780 * _does_ do is to "re-match" the stat information of a file 781 * with the cache, so that you can refresh the cache for a 782 * file that hasn't been changed but where the stat entry is 783 * out of date. 784 * 785 * For example, you'd want to do this after doing a "git-read-tree", 786 * to link up the stat cache details with the proper files. 787 */ 788static struct cache_entry *refresh_cache_ent(struct index_state *istate, 789 struct cache_entry *ce, 790 unsigned int options, int *err) 791{ 792 struct stat st; 793 struct cache_entry *updated; 794 int changed, size; 795 int ignore_valid = options & CE_MATCH_IGNORE_VALID; 796 797 if (lstat(ce->name, &st) < 0) { 798 if (err) 799 *err = errno; 800 return NULL; 801 } 802 803 changed = ie_match_stat(istate, ce, &st, options); 804 if (!changed) { 805 /* 806 * The path is unchanged. If we were told to ignore 807 * valid bit, then we did the actual stat check and 808 * found that the entry is unmodified. If the entry 809 * is not marked VALID, this is the place to mark it 810 * valid again, under "assume unchanged" mode. 811 */ 812 if (ignore_valid && assume_unchanged && 813 !(ce->ce_flags & htons(CE_VALID))) 814 ; /* mark this one VALID again */ 815 else 816 return ce; 817 } 818 819 if (ie_modified(istate, ce, &st, options)) { 820 if (err) 821 *err = EINVAL; 822 return NULL; 823 } 824 825 size = ce_size(ce); 826 updated = xmalloc(size); 827 memcpy(updated, ce, size); 828 fill_stat_cache_info(updated, &st); 829 830 /* 831 * If ignore_valid is not set, we should leave CE_VALID bit 832 * alone. Otherwise, paths marked with --no-assume-unchanged 833 * (i.e. things to be edited) will reacquire CE_VALID bit 834 * automatically, which is not really what we want. 835 */ 836 if (!ignore_valid && assume_unchanged && 837 !(ce->ce_flags & htons(CE_VALID))) 838 updated->ce_flags &= ~htons(CE_VALID); 839 840 return updated; 841} 842 843int refresh_index(struct index_state *istate, unsigned int flags, const char **pathspec, char *seen) 844{ 845 int i; 846 int has_errors = 0; 847 int really = (flags & REFRESH_REALLY) != 0; 848 int allow_unmerged = (flags & REFRESH_UNMERGED) != 0; 849 int quiet = (flags & REFRESH_QUIET) != 0; 850 int not_new = (flags & REFRESH_IGNORE_MISSING) != 0; 851 unsigned int options = really ? CE_MATCH_IGNORE_VALID : 0; 852 853 for (i = 0; i < istate->cache_nr; i++) { 854 struct cache_entry *ce, *new; 855 int cache_errno = 0; 856 857 ce = istate->cache[i]; 858 if (ce_stage(ce)) { 859 while ((i < istate->cache_nr) && 860 ! strcmp(istate->cache[i]->name, ce->name)) 861 i++; 862 i--; 863 if (allow_unmerged) 864 continue; 865 printf("%s: needs merge\n", ce->name); 866 has_errors = 1; 867 continue; 868 } 869 870 if (pathspec && !match_pathspec(pathspec, ce->name, strlen(ce->name), 0, seen)) 871 continue; 872 873 new = refresh_cache_ent(istate, ce, options, &cache_errno); 874 if (new == ce) 875 continue; 876 if (!new) { 877 if (not_new && cache_errno == ENOENT) 878 continue; 879 if (really && cache_errno == EINVAL) { 880 /* If we are doing --really-refresh that 881 * means the index is not valid anymore. 882 */ 883 ce->ce_flags &= ~htons(CE_VALID); 884 istate->cache_changed = 1; 885 } 886 if (quiet) 887 continue; 888 printf("%s: needs update\n", ce->name); 889 has_errors = 1; 890 continue; 891 } 892 istate->cache_changed = 1; 893 /* You can NOT just free istate->cache[i] here, since it 894 * might not be necessarily malloc()ed but can also come 895 * from mmap(). */ 896 istate->cache[i] = new; 897 } 898 return has_errors; 899} 900 901struct cache_entry *refresh_cache_entry(struct cache_entry *ce, int really) 902{ 903 return refresh_cache_ent(&the_index, ce, really, NULL); 904} 905 906static int verify_hdr(struct cache_header *hdr, unsigned long size) 907{ 908 SHA_CTX c; 909 unsigned char sha1[20]; 910 911 if (hdr->hdr_signature != htonl(CACHE_SIGNATURE)) 912 return error("bad signature"); 913 if (hdr->hdr_version != htonl(2)) 914 return error("bad index version"); 915 SHA1_Init(&c); 916 SHA1_Update(&c, hdr, size - 20); 917 SHA1_Final(sha1, &c); 918 if (hashcmp(sha1, (unsigned char *)hdr + size - 20)) 919 return error("bad index file sha1 signature"); 920 return 0; 921} 922 923static int read_index_extension(struct index_state *istate, 924 const char *ext, void *data, unsigned long sz) 925{ 926 switch (CACHE_EXT(ext)) { 927 case CACHE_EXT_TREE: 928 istate->cache_tree = cache_tree_read(data, sz); 929 break; 930 default: 931 if (*ext < 'A' || 'Z' < *ext) 932 return error("index uses %.4s extension, which we do not understand", 933 ext); 934 fprintf(stderr, "ignoring %.4s extension\n", ext); 935 break; 936 } 937 return 0; 938} 939 940int read_index(struct index_state *istate) 941{ 942 return read_index_from(istate, get_index_file()); 943} 944 945/* remember to discard_cache() before reading a different cache! */ 946int read_index_from(struct index_state *istate, const char *path) 947{ 948 int fd, i; 949 struct stat st; 950 unsigned long offset; 951 struct cache_header *hdr; 952 953 errno = EBUSY; 954 if (istate->mmap) 955 return istate->cache_nr; 956 957 errno = ENOENT; 958 istate->timestamp = 0; 959 fd = open(path, O_RDONLY); 960 if (fd < 0) { 961 if (errno == ENOENT) 962 return 0; 963 die("index file open failed (%s)", strerror(errno)); 964 } 965 966 if (fstat(fd, &st)) 967 die("cannot stat the open index (%s)", strerror(errno)); 968 969 errno = EINVAL; 970 istate->mmap_size = xsize_t(st.st_size); 971 if (istate->mmap_size < sizeof(struct cache_header) + 20) 972 die("index file smaller than expected"); 973 974 istate->mmap = xmmap(NULL, istate->mmap_size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0); 975 close(fd); 976 977 hdr = istate->mmap; 978 if (verify_hdr(hdr, istate->mmap_size) < 0) 979 goto unmap; 980 981 istate->cache_nr = ntohl(hdr->hdr_entries); 982 istate->cache_alloc = alloc_nr(istate->cache_nr); 983 istate->cache = xcalloc(istate->cache_alloc, sizeof(struct cache_entry *)); 984 985 offset = sizeof(*hdr); 986 for (i = 0; i < istate->cache_nr; i++) { 987 struct cache_entry *ce; 988 989 ce = (struct cache_entry *)((char *)(istate->mmap) + offset); 990 offset = offset + ce_size(ce); 991 istate->cache[i] = ce; 992 } 993 istate->timestamp = st.st_mtime; 994 while (offset <= istate->mmap_size - 20 - 8) { 995 /* After an array of active_nr index entries, 996 * there can be arbitrary number of extended 997 * sections, each of which is prefixed with 998 * extension name (4-byte) and section length 999 * in 4-byte network byte order.1000 */1001 unsigned long extsize;1002 memcpy(&extsize, (char *)(istate->mmap) + offset + 4, 4);1003 extsize = ntohl(extsize);1004 if (read_index_extension(istate,1005 ((const char *) (istate->mmap)) + offset,1006 (char *) (istate->mmap) + offset + 8,1007 extsize) < 0)1008 goto unmap;1009 offset += 8;1010 offset += extsize;1011 }1012 return istate->cache_nr;10131014unmap:1015 munmap(istate->mmap, istate->mmap_size);1016 errno = EINVAL;1017 die("index file corrupt");1018}10191020int discard_index(struct index_state *istate)1021{1022 int ret;10231024 istate->cache_nr = 0;1025 istate->cache_changed = 0;1026 istate->timestamp = 0;1027 cache_tree_free(&(istate->cache_tree));1028 if (istate->mmap == NULL)1029 return 0;1030 ret = munmap(istate->mmap, istate->mmap_size);1031 istate->mmap = NULL;1032 istate->mmap_size = 0;10331034 /* no need to throw away allocated active_cache */1035 return ret;1036}10371038#define WRITE_BUFFER_SIZE 81921039static unsigned char write_buffer[WRITE_BUFFER_SIZE];1040static unsigned long write_buffer_len;10411042static int ce_write_flush(SHA_CTX *context, int fd)1043{1044 unsigned int buffered = write_buffer_len;1045 if (buffered) {1046 SHA1_Update(context, write_buffer, buffered);1047 if (write_in_full(fd, write_buffer, buffered) != buffered)1048 return -1;1049 write_buffer_len = 0;1050 }1051 return 0;1052}10531054static int ce_write(SHA_CTX *context, int fd, void *data, unsigned int len)1055{1056 while (len) {1057 unsigned int buffered = write_buffer_len;1058 unsigned int partial = WRITE_BUFFER_SIZE - buffered;1059 if (partial > len)1060 partial = len;1061 memcpy(write_buffer + buffered, data, partial);1062 buffered += partial;1063 if (buffered == WRITE_BUFFER_SIZE) {1064 write_buffer_len = buffered;1065 if (ce_write_flush(context, fd))1066 return -1;1067 buffered = 0;1068 }1069 write_buffer_len = buffered;1070 len -= partial;1071 data = (char *) data + partial;1072 }1073 return 0;1074}10751076static int write_index_ext_header(SHA_CTX *context, int fd,1077 unsigned int ext, unsigned int sz)1078{1079 ext = htonl(ext);1080 sz = htonl(sz);1081 return ((ce_write(context, fd, &ext, 4) < 0) ||1082 (ce_write(context, fd, &sz, 4) < 0)) ? -1 : 0;1083}10841085static int ce_flush(SHA_CTX *context, int fd)1086{1087 unsigned int left = write_buffer_len;10881089 if (left) {1090 write_buffer_len = 0;1091 SHA1_Update(context, write_buffer, left);1092 }10931094 /* Flush first if not enough space for SHA1 signature */1095 if (left + 20 > WRITE_BUFFER_SIZE) {1096 if (write_in_full(fd, write_buffer, left) != left)1097 return -1;1098 left = 0;1099 }11001101 /* Append the SHA1 signature at the end */1102 SHA1_Final(write_buffer + left, context);1103 left += 20;1104 return (write_in_full(fd, write_buffer, left) != left) ? -1 : 0;1105}11061107static void ce_smudge_racily_clean_entry(struct cache_entry *ce)1108{1109 /*1110 * The only thing we care about in this function is to smudge the1111 * falsely clean entry due to touch-update-touch race, so we leave1112 * everything else as they are. We are called for entries whose1113 * ce_mtime match the index file mtime.1114 */1115 struct stat st;11161117 if (lstat(ce->name, &st) < 0)1118 return;1119 if (ce_match_stat_basic(ce, &st))1120 return;1121 if (ce_modified_check_fs(ce, &st)) {1122 /* This is "racily clean"; smudge it. Note that this1123 * is a tricky code. At first glance, it may appear1124 * that it can break with this sequence:1125 *1126 * $ echo xyzzy >frotz1127 * $ git-update-index --add frotz1128 * $ : >frotz1129 * $ sleep 31130 * $ echo filfre >nitfol1131 * $ git-update-index --add nitfol1132 *1133 * but it does not. When the second update-index runs,1134 * it notices that the entry "frotz" has the same timestamp1135 * as index, and if we were to smudge it by resetting its1136 * size to zero here, then the object name recorded1137 * in index is the 6-byte file but the cached stat information1138 * becomes zero --- which would then match what we would1139 * obtain from the filesystem next time we stat("frotz").1140 *1141 * However, the second update-index, before calling1142 * this function, notices that the cached size is 61143 * bytes and what is on the filesystem is an empty1144 * file, and never calls us, so the cached size information1145 * for "frotz" stays 6 which does not match the filesystem.1146 */1147 ce->ce_size = htonl(0);1148 }1149}11501151int write_index(struct index_state *istate, int newfd)1152{1153 SHA_CTX c;1154 struct cache_header hdr;1155 int i, err, removed;1156 struct cache_entry **cache = istate->cache;1157 int entries = istate->cache_nr;11581159 for (i = removed = 0; i < entries; i++)1160 if (!cache[i]->ce_mode)1161 removed++;11621163 hdr.hdr_signature = htonl(CACHE_SIGNATURE);1164 hdr.hdr_version = htonl(2);1165 hdr.hdr_entries = htonl(entries - removed);11661167 SHA1_Init(&c);1168 if (ce_write(&c, newfd, &hdr, sizeof(hdr)) < 0)1169 return -1;11701171 for (i = 0; i < entries; i++) {1172 struct cache_entry *ce = cache[i];1173 if (!ce->ce_mode)1174 continue;1175 if (istate->timestamp &&1176 istate->timestamp <= ntohl(ce->ce_mtime.sec))1177 ce_smudge_racily_clean_entry(ce);1178 if (ce_write(&c, newfd, ce, ce_size(ce)) < 0)1179 return -1;1180 }11811182 /* Write extension data here */1183 if (istate->cache_tree) {1184 struct strbuf sb;11851186 strbuf_init(&sb, 0);1187 cache_tree_write(&sb, istate->cache_tree);1188 err = write_index_ext_header(&c, newfd, CACHE_EXT_TREE, sb.len) < 01189 || ce_write(&c, newfd, sb.buf, sb.len) < 0;1190 strbuf_release(&sb);1191 if (err)1192 return -1;1193 }1194 return ce_flush(&c, newfd);1195}