1#include "../cache.h" 2#include "../refs.h" 3#include "refs-internal.h" 4#include "../iterator.h" 5#include "../dir-iterator.h" 6#include "../lockfile.h" 7#include "../object.h" 8#include "../dir.h" 9 10struct ref_lock { 11 char *ref_name; 12 struct lock_file *lk; 13 struct object_id old_oid; 14}; 15 16struct ref_entry; 17 18/* 19 * Information used (along with the information in ref_entry) to 20 * describe a single cached reference. This data structure only 21 * occurs embedded in a union in struct ref_entry, and only when 22 * (ref_entry->flag & REF_DIR) is zero. 23 */ 24struct ref_value { 25 /* 26 * The name of the object to which this reference resolves 27 * (which may be a tag object). If REF_ISBROKEN, this is 28 * null. If REF_ISSYMREF, then this is the name of the object 29 * referred to by the last reference in the symlink chain. 30 */ 31 struct object_id oid; 32 33 /* 34 * If REF_KNOWS_PEELED, then this field holds the peeled value 35 * of this reference, or null if the reference is known not to 36 * be peelable. See the documentation for peel_ref() for an 37 * exact definition of "peelable". 38 */ 39 struct object_id peeled; 40}; 41 42struct files_ref_store; 43 44/* 45 * Information used (along with the information in ref_entry) to 46 * describe a level in the hierarchy of references. This data 47 * structure only occurs embedded in a union in struct ref_entry, and 48 * only when (ref_entry.flag & REF_DIR) is set. In that case, 49 * (ref_entry.flag & REF_INCOMPLETE) determines whether the references 50 * in the directory have already been read: 51 * 52 * (ref_entry.flag & REF_INCOMPLETE) unset -- a directory of loose 53 * or packed references, already read. 54 * 55 * (ref_entry.flag & REF_INCOMPLETE) set -- a directory of loose 56 * references that hasn't been read yet (nor has any of its 57 * subdirectories). 58 * 59 * Entries within a directory are stored within a growable array of 60 * pointers to ref_entries (entries, nr, alloc). Entries 0 <= i < 61 * sorted are sorted by their component name in strcmp() order and the 62 * remaining entries are unsorted. 63 * 64 * Loose references are read lazily, one directory at a time. When a 65 * directory of loose references is read, then all of the references 66 * in that directory are stored, and REF_INCOMPLETE stubs are created 67 * for any subdirectories, but the subdirectories themselves are not 68 * read. The reading is triggered by get_ref_dir(). 69 */ 70struct ref_dir { 71 int nr, alloc; 72 73 /* 74 * Entries with index 0 <= i < sorted are sorted by name. New 75 * entries are appended to the list unsorted, and are sorted 76 * only when required; thus we avoid the need to sort the list 77 * after the addition of every reference. 78 */ 79 int sorted; 80 81 /* A pointer to the files_ref_store that contains this ref_dir. */ 82 struct files_ref_store *ref_store; 83 84 struct ref_entry **entries; 85}; 86 87/* 88 * Bit values for ref_entry::flag. REF_ISSYMREF=0x01, 89 * REF_ISPACKED=0x02, REF_ISBROKEN=0x04 and REF_BAD_NAME=0x08 are 90 * public values; see refs.h. 91 */ 92 93/* 94 * The field ref_entry->u.value.peeled of this value entry contains 95 * the correct peeled value for the reference, which might be 96 * null_sha1 if the reference is not a tag or if it is broken. 97 */ 98#define REF_KNOWS_PEELED 0x10 99 100/* ref_entry represents a directory of references */ 101#define REF_DIR 0x20 102 103/* 104 * Entry has not yet been read from disk (used only for REF_DIR 105 * entries representing loose references) 106 */ 107#define REF_INCOMPLETE 0x40 108 109/* 110 * A ref_entry represents either a reference or a "subdirectory" of 111 * references. 112 * 113 * Each directory in the reference namespace is represented by a 114 * ref_entry with (flags & REF_DIR) set and containing a subdir member 115 * that holds the entries in that directory that have been read so 116 * far. If (flags & REF_INCOMPLETE) is set, then the directory and 117 * its subdirectories haven't been read yet. REF_INCOMPLETE is only 118 * used for loose reference directories. 119 * 120 * References are represented by a ref_entry with (flags & REF_DIR) 121 * unset and a value member that describes the reference's value. The 122 * flag member is at the ref_entry level, but it is also needed to 123 * interpret the contents of the value field (in other words, a 124 * ref_value object is not very much use without the enclosing 125 * ref_entry). 126 * 127 * Reference names cannot end with slash and directories' names are 128 * always stored with a trailing slash (except for the top-level 129 * directory, which is always denoted by ""). This has two nice 130 * consequences: (1) when the entries in each subdir are sorted 131 * lexicographically by name (as they usually are), the references in 132 * a whole tree can be generated in lexicographic order by traversing 133 * the tree in left-to-right, depth-first order; (2) the names of 134 * references and subdirectories cannot conflict, and therefore the 135 * presence of an empty subdirectory does not block the creation of a 136 * similarly-named reference. (The fact that reference names with the 137 * same leading components can conflict *with each other* is a 138 * separate issue that is regulated by verify_refname_available().) 139 * 140 * Please note that the name field contains the fully-qualified 141 * reference (or subdirectory) name. Space could be saved by only 142 * storing the relative names. But that would require the full names 143 * to be generated on the fly when iterating in do_for_each_ref(), and 144 * would break callback functions, who have always been able to assume 145 * that the name strings that they are passed will not be freed during 146 * the iteration. 147 */ 148struct ref_entry { 149 unsigned char flag; /* ISSYMREF? ISPACKED? */ 150 union { 151 struct ref_value value; /* if not (flags&REF_DIR) */ 152 struct ref_dir subdir; /* if (flags&REF_DIR) */ 153 } u; 154 /* 155 * The full name of the reference (e.g., "refs/heads/master") 156 * or the full name of the directory with a trailing slash 157 * (e.g., "refs/heads/"): 158 */ 159 char name[FLEX_ARRAY]; 160}; 161 162static void read_loose_refs(const char *dirname, struct ref_dir *dir); 163static int search_ref_dir(struct ref_dir *dir, const char *refname, size_t len); 164static struct ref_entry *create_dir_entry(struct files_ref_store *ref_store, 165 const char *dirname, size_t len, 166 int incomplete); 167static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry); 168static int files_log_ref_write(struct files_ref_store *refs, 169 const char *refname, const unsigned char *old_sha1, 170 const unsigned char *new_sha1, const char *msg, 171 int flags, struct strbuf *err); 172 173static struct ref_dir *get_ref_dir(struct ref_entry *entry) 174{ 175 struct ref_dir *dir; 176 assert(entry->flag & REF_DIR); 177 dir = &entry->u.subdir; 178 if (entry->flag & REF_INCOMPLETE) { 179 read_loose_refs(entry->name, dir); 180 181 /* 182 * Manually add refs/bisect, which, being 183 * per-worktree, might not appear in the directory 184 * listing for refs/ in the main repo. 185 */ 186 if (!strcmp(entry->name, "refs/")) { 187 int pos = search_ref_dir(dir, "refs/bisect/", 12); 188 if (pos < 0) { 189 struct ref_entry *child_entry; 190 child_entry = create_dir_entry(dir->ref_store, 191 "refs/bisect/", 192 12, 1); 193 add_entry_to_dir(dir, child_entry); 194 read_loose_refs("refs/bisect", 195 &child_entry->u.subdir); 196 } 197 } 198 entry->flag &= ~REF_INCOMPLETE; 199 } 200 return dir; 201} 202 203static struct ref_entry *create_ref_entry(const char *refname, 204 const unsigned char *sha1, int flag, 205 int check_name) 206{ 207 struct ref_entry *ref; 208 209 if (check_name && 210 check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) 211 die("Reference has invalid format: '%s'", refname); 212 FLEX_ALLOC_STR(ref, name, refname); 213 hashcpy(ref->u.value.oid.hash, sha1); 214 oidclr(&ref->u.value.peeled); 215 ref->flag = flag; 216 return ref; 217} 218 219static void clear_ref_dir(struct ref_dir *dir); 220 221static void free_ref_entry(struct ref_entry *entry) 222{ 223 if (entry->flag & REF_DIR) { 224 /* 225 * Do not use get_ref_dir() here, as that might 226 * trigger the reading of loose refs. 227 */ 228 clear_ref_dir(&entry->u.subdir); 229 } 230 free(entry); 231} 232 233/* 234 * Add a ref_entry to the end of dir (unsorted). Entry is always 235 * stored directly in dir; no recursion into subdirectories is 236 * done. 237 */ 238static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry) 239{ 240 ALLOC_GROW(dir->entries, dir->nr + 1, dir->alloc); 241 dir->entries[dir->nr++] = entry; 242 /* optimize for the case that entries are added in order */ 243 if (dir->nr == 1 || 244 (dir->nr == dir->sorted + 1 && 245 strcmp(dir->entries[dir->nr - 2]->name, 246 dir->entries[dir->nr - 1]->name) < 0)) 247 dir->sorted = dir->nr; 248} 249 250/* 251 * Clear and free all entries in dir, recursively. 252 */ 253static void clear_ref_dir(struct ref_dir *dir) 254{ 255 int i; 256 for (i = 0; i < dir->nr; i++) 257 free_ref_entry(dir->entries[i]); 258 free(dir->entries); 259 dir->sorted = dir->nr = dir->alloc = 0; 260 dir->entries = NULL; 261} 262 263/* 264 * Create a struct ref_entry object for the specified dirname. 265 * dirname is the name of the directory with a trailing slash (e.g., 266 * "refs/heads/") or "" for the top-level directory. 267 */ 268static struct ref_entry *create_dir_entry(struct files_ref_store *ref_store, 269 const char *dirname, size_t len, 270 int incomplete) 271{ 272 struct ref_entry *direntry; 273 FLEX_ALLOC_MEM(direntry, name, dirname, len); 274 direntry->u.subdir.ref_store = ref_store; 275 direntry->flag = REF_DIR | (incomplete ? REF_INCOMPLETE : 0); 276 return direntry; 277} 278 279static int ref_entry_cmp(const void *a, const void *b) 280{ 281 struct ref_entry *one = *(struct ref_entry **)a; 282 struct ref_entry *two = *(struct ref_entry **)b; 283 return strcmp(one->name, two->name); 284} 285 286static void sort_ref_dir(struct ref_dir *dir); 287 288struct string_slice { 289 size_t len; 290 const char *str; 291}; 292 293static int ref_entry_cmp_sslice(const void *key_, const void *ent_) 294{ 295 const struct string_slice *key = key_; 296 const struct ref_entry *ent = *(const struct ref_entry * const *)ent_; 297 int cmp = strncmp(key->str, ent->name, key->len); 298 if (cmp) 299 return cmp; 300 return '\0' - (unsigned char)ent->name[key->len]; 301} 302 303/* 304 * Return the index of the entry with the given refname from the 305 * ref_dir (non-recursively), sorting dir if necessary. Return -1 if 306 * no such entry is found. dir must already be complete. 307 */ 308static int search_ref_dir(struct ref_dir *dir, const char *refname, size_t len) 309{ 310 struct ref_entry **r; 311 struct string_slice key; 312 313 if (refname == NULL || !dir->nr) 314 return -1; 315 316 sort_ref_dir(dir); 317 key.len = len; 318 key.str = refname; 319 r = bsearch(&key, dir->entries, dir->nr, sizeof(*dir->entries), 320 ref_entry_cmp_sslice); 321 322 if (r == NULL) 323 return -1; 324 325 return r - dir->entries; 326} 327 328/* 329 * Search for a directory entry directly within dir (without 330 * recursing). Sort dir if necessary. subdirname must be a directory 331 * name (i.e., end in '/'). If mkdir is set, then create the 332 * directory if it is missing; otherwise, return NULL if the desired 333 * directory cannot be found. dir must already be complete. 334 */ 335static struct ref_dir *search_for_subdir(struct ref_dir *dir, 336 const char *subdirname, size_t len, 337 int mkdir) 338{ 339 int entry_index = search_ref_dir(dir, subdirname, len); 340 struct ref_entry *entry; 341 if (entry_index == -1) { 342 if (!mkdir) 343 return NULL; 344 /* 345 * Since dir is complete, the absence of a subdir 346 * means that the subdir really doesn't exist; 347 * therefore, create an empty record for it but mark 348 * the record complete. 349 */ 350 entry = create_dir_entry(dir->ref_store, subdirname, len, 0); 351 add_entry_to_dir(dir, entry); 352 } else { 353 entry = dir->entries[entry_index]; 354 } 355 return get_ref_dir(entry); 356} 357 358/* 359 * If refname is a reference name, find the ref_dir within the dir 360 * tree that should hold refname. If refname is a directory name 361 * (i.e., ends in '/'), then return that ref_dir itself. dir must 362 * represent the top-level directory and must already be complete. 363 * Sort ref_dirs and recurse into subdirectories as necessary. If 364 * mkdir is set, then create any missing directories; otherwise, 365 * return NULL if the desired directory cannot be found. 366 */ 367static struct ref_dir *find_containing_dir(struct ref_dir *dir, 368 const char *refname, int mkdir) 369{ 370 const char *slash; 371 for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) { 372 size_t dirnamelen = slash - refname + 1; 373 struct ref_dir *subdir; 374 subdir = search_for_subdir(dir, refname, dirnamelen, mkdir); 375 if (!subdir) { 376 dir = NULL; 377 break; 378 } 379 dir = subdir; 380 } 381 382 return dir; 383} 384 385/* 386 * Find the value entry with the given name in dir, sorting ref_dirs 387 * and recursing into subdirectories as necessary. If the name is not 388 * found or it corresponds to a directory entry, return NULL. 389 */ 390static struct ref_entry *find_ref(struct ref_dir *dir, const char *refname) 391{ 392 int entry_index; 393 struct ref_entry *entry; 394 dir = find_containing_dir(dir, refname, 0); 395 if (!dir) 396 return NULL; 397 entry_index = search_ref_dir(dir, refname, strlen(refname)); 398 if (entry_index == -1) 399 return NULL; 400 entry = dir->entries[entry_index]; 401 return (entry->flag & REF_DIR) ? NULL : entry; 402} 403 404/* 405 * Remove the entry with the given name from dir, recursing into 406 * subdirectories as necessary. If refname is the name of a directory 407 * (i.e., ends with '/'), then remove the directory and its contents. 408 * If the removal was successful, return the number of entries 409 * remaining in the directory entry that contained the deleted entry. 410 * If the name was not found, return -1. Please note that this 411 * function only deletes the entry from the cache; it does not delete 412 * it from the filesystem or ensure that other cache entries (which 413 * might be symbolic references to the removed entry) are updated. 414 * Nor does it remove any containing dir entries that might be made 415 * empty by the removal. dir must represent the top-level directory 416 * and must already be complete. 417 */ 418static int remove_entry(struct ref_dir *dir, const char *refname) 419{ 420 int refname_len = strlen(refname); 421 int entry_index; 422 struct ref_entry *entry; 423 int is_dir = refname[refname_len - 1] == '/'; 424 if (is_dir) { 425 /* 426 * refname represents a reference directory. Remove 427 * the trailing slash; otherwise we will get the 428 * directory *representing* refname rather than the 429 * one *containing* it. 430 */ 431 char *dirname = xmemdupz(refname, refname_len - 1); 432 dir = find_containing_dir(dir, dirname, 0); 433 free(dirname); 434 } else { 435 dir = find_containing_dir(dir, refname, 0); 436 } 437 if (!dir) 438 return -1; 439 entry_index = search_ref_dir(dir, refname, refname_len); 440 if (entry_index == -1) 441 return -1; 442 entry = dir->entries[entry_index]; 443 444 memmove(&dir->entries[entry_index], 445 &dir->entries[entry_index + 1], 446 (dir->nr - entry_index - 1) * sizeof(*dir->entries) 447 ); 448 dir->nr--; 449 if (dir->sorted > entry_index) 450 dir->sorted--; 451 free_ref_entry(entry); 452 return dir->nr; 453} 454 455/* 456 * Add a ref_entry to the ref_dir (unsorted), recursing into 457 * subdirectories as necessary. dir must represent the top-level 458 * directory. Return 0 on success. 459 */ 460static int add_ref(struct ref_dir *dir, struct ref_entry *ref) 461{ 462 dir = find_containing_dir(dir, ref->name, 1); 463 if (!dir) 464 return -1; 465 add_entry_to_dir(dir, ref); 466 return 0; 467} 468 469/* 470 * Emit a warning and return true iff ref1 and ref2 have the same name 471 * and the same sha1. Die if they have the same name but different 472 * sha1s. 473 */ 474static int is_dup_ref(const struct ref_entry *ref1, const struct ref_entry *ref2) 475{ 476 if (strcmp(ref1->name, ref2->name)) 477 return 0; 478 479 /* Duplicate name; make sure that they don't conflict: */ 480 481 if ((ref1->flag & REF_DIR) || (ref2->flag & REF_DIR)) 482 /* This is impossible by construction */ 483 die("Reference directory conflict: %s", ref1->name); 484 485 if (oidcmp(&ref1->u.value.oid, &ref2->u.value.oid)) 486 die("Duplicated ref, and SHA1s don't match: %s", ref1->name); 487 488 warning("Duplicated ref: %s", ref1->name); 489 return 1; 490} 491 492/* 493 * Sort the entries in dir non-recursively (if they are not already 494 * sorted) and remove any duplicate entries. 495 */ 496static void sort_ref_dir(struct ref_dir *dir) 497{ 498 int i, j; 499 struct ref_entry *last = NULL; 500 501 /* 502 * This check also prevents passing a zero-length array to qsort(), 503 * which is a problem on some platforms. 504 */ 505 if (dir->sorted == dir->nr) 506 return; 507 508 QSORT(dir->entries, dir->nr, ref_entry_cmp); 509 510 /* Remove any duplicates: */ 511 for (i = 0, j = 0; j < dir->nr; j++) { 512 struct ref_entry *entry = dir->entries[j]; 513 if (last && is_dup_ref(last, entry)) 514 free_ref_entry(entry); 515 else 516 last = dir->entries[i++] = entry; 517 } 518 dir->sorted = dir->nr = i; 519} 520 521/* 522 * Return true if refname, which has the specified oid and flags, can 523 * be resolved to an object in the database. If the referred-to object 524 * does not exist, emit a warning and return false. 525 */ 526static int ref_resolves_to_object(const char *refname, 527 const struct object_id *oid, 528 unsigned int flags) 529{ 530 if (flags & REF_ISBROKEN) 531 return 0; 532 if (!has_sha1_file(oid->hash)) { 533 error("%s does not point to a valid object!", refname); 534 return 0; 535 } 536 return 1; 537} 538 539/* 540 * Return true if the reference described by entry can be resolved to 541 * an object in the database; otherwise, emit a warning and return 542 * false. 543 */ 544static int entry_resolves_to_object(struct ref_entry *entry) 545{ 546 return ref_resolves_to_object(entry->name, 547 &entry->u.value.oid, entry->flag); 548} 549 550typedef int each_ref_entry_fn(struct ref_entry *entry, void *cb_data); 551 552/* 553 * Call fn for each reference in dir that has index in the range 554 * offset <= index < dir->nr. Recurse into subdirectories that are in 555 * that index range, sorting them before iterating. This function 556 * does not sort dir itself; it should be sorted beforehand. fn is 557 * called for all references, including broken ones. 558 */ 559static int do_for_each_entry_in_dir(struct ref_dir *dir, int offset, 560 each_ref_entry_fn fn, void *cb_data) 561{ 562 int i; 563 assert(dir->sorted == dir->nr); 564 for (i = offset; i < dir->nr; i++) { 565 struct ref_entry *entry = dir->entries[i]; 566 int retval; 567 if (entry->flag & REF_DIR) { 568 struct ref_dir *subdir = get_ref_dir(entry); 569 sort_ref_dir(subdir); 570 retval = do_for_each_entry_in_dir(subdir, 0, fn, cb_data); 571 } else { 572 retval = fn(entry, cb_data); 573 } 574 if (retval) 575 return retval; 576 } 577 return 0; 578} 579 580/* 581 * Load all of the refs from the dir into our in-memory cache. The hard work 582 * of loading loose refs is done by get_ref_dir(), so we just need to recurse 583 * through all of the sub-directories. We do not even need to care about 584 * sorting, as traversal order does not matter to us. 585 */ 586static void prime_ref_dir(struct ref_dir *dir) 587{ 588 int i; 589 for (i = 0; i < dir->nr; i++) { 590 struct ref_entry *entry = dir->entries[i]; 591 if (entry->flag & REF_DIR) 592 prime_ref_dir(get_ref_dir(entry)); 593 } 594} 595 596/* 597 * A level in the reference hierarchy that is currently being iterated 598 * through. 599 */ 600struct cache_ref_iterator_level { 601 /* 602 * The ref_dir being iterated over at this level. The ref_dir 603 * is sorted before being stored here. 604 */ 605 struct ref_dir *dir; 606 607 /* 608 * The index of the current entry within dir (which might 609 * itself be a directory). If index == -1, then the iteration 610 * hasn't yet begun. If index == dir->nr, then the iteration 611 * through this level is over. 612 */ 613 int index; 614}; 615 616/* 617 * Represent an iteration through a ref_dir in the memory cache. The 618 * iteration recurses through subdirectories. 619 */ 620struct cache_ref_iterator { 621 struct ref_iterator base; 622 623 /* 624 * The number of levels currently on the stack. This is always 625 * at least 1, because when it becomes zero the iteration is 626 * ended and this struct is freed. 627 */ 628 size_t levels_nr; 629 630 /* The number of levels that have been allocated on the stack */ 631 size_t levels_alloc; 632 633 /* 634 * A stack of levels. levels[0] is the uppermost level that is 635 * being iterated over in this iteration. (This is not 636 * necessary the top level in the references hierarchy. If we 637 * are iterating through a subtree, then levels[0] will hold 638 * the ref_dir for that subtree, and subsequent levels will go 639 * on from there.) 640 */ 641 struct cache_ref_iterator_level *levels; 642}; 643 644static int cache_ref_iterator_advance(struct ref_iterator *ref_iterator) 645{ 646 struct cache_ref_iterator *iter = 647 (struct cache_ref_iterator *)ref_iterator; 648 649 while (1) { 650 struct cache_ref_iterator_level *level = 651 &iter->levels[iter->levels_nr - 1]; 652 struct ref_dir *dir = level->dir; 653 struct ref_entry *entry; 654 655 if (level->index == -1) 656 sort_ref_dir(dir); 657 658 if (++level->index == level->dir->nr) { 659 /* This level is exhausted; pop up a level */ 660 if (--iter->levels_nr == 0) 661 return ref_iterator_abort(ref_iterator); 662 663 continue; 664 } 665 666 entry = dir->entries[level->index]; 667 668 if (entry->flag & REF_DIR) { 669 /* push down a level */ 670 ALLOC_GROW(iter->levels, iter->levels_nr + 1, 671 iter->levels_alloc); 672 673 level = &iter->levels[iter->levels_nr++]; 674 level->dir = get_ref_dir(entry); 675 level->index = -1; 676 } else { 677 iter->base.refname = entry->name; 678 iter->base.oid = &entry->u.value.oid; 679 iter->base.flags = entry->flag; 680 return ITER_OK; 681 } 682 } 683} 684 685static enum peel_status peel_entry(struct ref_entry *entry, int repeel); 686 687static int cache_ref_iterator_peel(struct ref_iterator *ref_iterator, 688 struct object_id *peeled) 689{ 690 struct cache_ref_iterator *iter = 691 (struct cache_ref_iterator *)ref_iterator; 692 struct cache_ref_iterator_level *level; 693 struct ref_entry *entry; 694 695 level = &iter->levels[iter->levels_nr - 1]; 696 697 if (level->index == -1) 698 die("BUG: peel called before advance for cache iterator"); 699 700 entry = level->dir->entries[level->index]; 701 702 if (peel_entry(entry, 0)) 703 return -1; 704 oidcpy(peeled, &entry->u.value.peeled); 705 return 0; 706} 707 708static int cache_ref_iterator_abort(struct ref_iterator *ref_iterator) 709{ 710 struct cache_ref_iterator *iter = 711 (struct cache_ref_iterator *)ref_iterator; 712 713 free(iter->levels); 714 base_ref_iterator_free(ref_iterator); 715 return ITER_DONE; 716} 717 718static struct ref_iterator_vtable cache_ref_iterator_vtable = { 719 cache_ref_iterator_advance, 720 cache_ref_iterator_peel, 721 cache_ref_iterator_abort 722}; 723 724static struct ref_iterator *cache_ref_iterator_begin(struct ref_dir *dir) 725{ 726 struct cache_ref_iterator *iter; 727 struct ref_iterator *ref_iterator; 728 struct cache_ref_iterator_level *level; 729 730 iter = xcalloc(1, sizeof(*iter)); 731 ref_iterator = &iter->base; 732 base_ref_iterator_init(ref_iterator, &cache_ref_iterator_vtable); 733 ALLOC_GROW(iter->levels, 10, iter->levels_alloc); 734 735 iter->levels_nr = 1; 736 level = &iter->levels[0]; 737 level->index = -1; 738 level->dir = dir; 739 740 return ref_iterator; 741} 742 743struct nonmatching_ref_data { 744 const struct string_list *skip; 745 const char *conflicting_refname; 746}; 747 748static int nonmatching_ref_fn(struct ref_entry *entry, void *vdata) 749{ 750 struct nonmatching_ref_data *data = vdata; 751 752 if (data->skip && string_list_has_string(data->skip, entry->name)) 753 return 0; 754 755 data->conflicting_refname = entry->name; 756 return 1; 757} 758 759/* 760 * Return 0 if a reference named refname could be created without 761 * conflicting with the name of an existing reference in dir. 762 * See verify_refname_available for more information. 763 */ 764static int verify_refname_available_dir(const char *refname, 765 const struct string_list *extras, 766 const struct string_list *skip, 767 struct ref_dir *dir, 768 struct strbuf *err) 769{ 770 const char *slash; 771 const char *extra_refname; 772 int pos; 773 struct strbuf dirname = STRBUF_INIT; 774 int ret = -1; 775 776 /* 777 * For the sake of comments in this function, suppose that 778 * refname is "refs/foo/bar". 779 */ 780 781 assert(err); 782 783 strbuf_grow(&dirname, strlen(refname) + 1); 784 for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) { 785 /* Expand dirname to the new prefix, not including the trailing slash: */ 786 strbuf_add(&dirname, refname + dirname.len, slash - refname - dirname.len); 787 788 /* 789 * We are still at a leading dir of the refname (e.g., 790 * "refs/foo"; if there is a reference with that name, 791 * it is a conflict, *unless* it is in skip. 792 */ 793 if (dir) { 794 pos = search_ref_dir(dir, dirname.buf, dirname.len); 795 if (pos >= 0 && 796 (!skip || !string_list_has_string(skip, dirname.buf))) { 797 /* 798 * We found a reference whose name is 799 * a proper prefix of refname; e.g., 800 * "refs/foo", and is not in skip. 801 */ 802 strbuf_addf(err, "'%s' exists; cannot create '%s'", 803 dirname.buf, refname); 804 goto cleanup; 805 } 806 } 807 808 if (extras && string_list_has_string(extras, dirname.buf) && 809 (!skip || !string_list_has_string(skip, dirname.buf))) { 810 strbuf_addf(err, "cannot process '%s' and '%s' at the same time", 811 refname, dirname.buf); 812 goto cleanup; 813 } 814 815 /* 816 * Otherwise, we can try to continue our search with 817 * the next component. So try to look up the 818 * directory, e.g., "refs/foo/". If we come up empty, 819 * we know there is nothing under this whole prefix, 820 * but even in that case we still have to continue the 821 * search for conflicts with extras. 822 */ 823 strbuf_addch(&dirname, '/'); 824 if (dir) { 825 pos = search_ref_dir(dir, dirname.buf, dirname.len); 826 if (pos < 0) { 827 /* 828 * There was no directory "refs/foo/", 829 * so there is nothing under this 830 * whole prefix. So there is no need 831 * to continue looking for conflicting 832 * references. But we need to continue 833 * looking for conflicting extras. 834 */ 835 dir = NULL; 836 } else { 837 dir = get_ref_dir(dir->entries[pos]); 838 } 839 } 840 } 841 842 /* 843 * We are at the leaf of our refname (e.g., "refs/foo/bar"). 844 * There is no point in searching for a reference with that 845 * name, because a refname isn't considered to conflict with 846 * itself. But we still need to check for references whose 847 * names are in the "refs/foo/bar/" namespace, because they 848 * *do* conflict. 849 */ 850 strbuf_addstr(&dirname, refname + dirname.len); 851 strbuf_addch(&dirname, '/'); 852 853 if (dir) { 854 pos = search_ref_dir(dir, dirname.buf, dirname.len); 855 856 if (pos >= 0) { 857 /* 858 * We found a directory named "$refname/" 859 * (e.g., "refs/foo/bar/"). It is a problem 860 * iff it contains any ref that is not in 861 * "skip". 862 */ 863 struct nonmatching_ref_data data; 864 865 data.skip = skip; 866 data.conflicting_refname = NULL; 867 dir = get_ref_dir(dir->entries[pos]); 868 sort_ref_dir(dir); 869 if (do_for_each_entry_in_dir(dir, 0, nonmatching_ref_fn, &data)) { 870 strbuf_addf(err, "'%s' exists; cannot create '%s'", 871 data.conflicting_refname, refname); 872 goto cleanup; 873 } 874 } 875 } 876 877 extra_refname = find_descendant_ref(dirname.buf, extras, skip); 878 if (extra_refname) 879 strbuf_addf(err, "cannot process '%s' and '%s' at the same time", 880 refname, extra_refname); 881 else 882 ret = 0; 883 884cleanup: 885 strbuf_release(&dirname); 886 return ret; 887} 888 889struct packed_ref_cache { 890 struct ref_entry *root; 891 892 /* 893 * Count of references to the data structure in this instance, 894 * including the pointer from files_ref_store::packed if any. 895 * The data will not be freed as long as the reference count 896 * is nonzero. 897 */ 898 unsigned int referrers; 899 900 /* 901 * Iff the packed-refs file associated with this instance is 902 * currently locked for writing, this points at the associated 903 * lock (which is owned by somebody else). The referrer count 904 * is also incremented when the file is locked and decremented 905 * when it is unlocked. 906 */ 907 struct lock_file *lock; 908 909 /* The metadata from when this packed-refs cache was read */ 910 struct stat_validity validity; 911}; 912 913/* 914 * Future: need to be in "struct repository" 915 * when doing a full libification. 916 */ 917struct files_ref_store { 918 struct ref_store base; 919 unsigned int store_flags; 920 921 char *gitdir; 922 char *gitcommondir; 923 char *packed_refs_path; 924 925 struct ref_entry *loose; 926 struct packed_ref_cache *packed; 927}; 928 929/* Lock used for the main packed-refs file: */ 930static struct lock_file packlock; 931 932/* 933 * Increment the reference count of *packed_refs. 934 */ 935static void acquire_packed_ref_cache(struct packed_ref_cache *packed_refs) 936{ 937 packed_refs->referrers++; 938} 939 940/* 941 * Decrease the reference count of *packed_refs. If it goes to zero, 942 * free *packed_refs and return true; otherwise return false. 943 */ 944static int release_packed_ref_cache(struct packed_ref_cache *packed_refs) 945{ 946 if (!--packed_refs->referrers) { 947 free_ref_entry(packed_refs->root); 948 stat_validity_clear(&packed_refs->validity); 949 free(packed_refs); 950 return 1; 951 } else { 952 return 0; 953 } 954} 955 956static void clear_packed_ref_cache(struct files_ref_store *refs) 957{ 958 if (refs->packed) { 959 struct packed_ref_cache *packed_refs = refs->packed; 960 961 if (packed_refs->lock) 962 die("internal error: packed-ref cache cleared while locked"); 963 refs->packed = NULL; 964 release_packed_ref_cache(packed_refs); 965 } 966} 967 968static void clear_loose_ref_cache(struct files_ref_store *refs) 969{ 970 if (refs->loose) { 971 free_ref_entry(refs->loose); 972 refs->loose = NULL; 973 } 974} 975 976/* 977 * Create a new submodule ref cache and add it to the internal 978 * set of caches. 979 */ 980static struct ref_store *files_ref_store_create(const char *gitdir, 981 unsigned int flags) 982{ 983 struct files_ref_store *refs = xcalloc(1, sizeof(*refs)); 984 struct ref_store *ref_store = (struct ref_store *)refs; 985 struct strbuf sb = STRBUF_INIT; 986 987 base_ref_store_init(ref_store, &refs_be_files); 988 refs->store_flags = flags; 989 990 refs->gitdir = xstrdup(gitdir); 991 get_common_dir_noenv(&sb, gitdir); 992 refs->gitcommondir = strbuf_detach(&sb, NULL); 993 strbuf_addf(&sb, "%s/packed-refs", refs->gitcommondir); 994 refs->packed_refs_path = strbuf_detach(&sb, NULL); 995 996 return ref_store; 997} 998 999/*1000 * Die if refs is not the main ref store. caller is used in any1001 * necessary error messages.1002 */1003static void files_assert_main_repository(struct files_ref_store *refs,1004 const char *caller)1005{1006 if (refs->store_flags & REF_STORE_MAIN)1007 return;10081009 die("BUG: operation %s only allowed for main ref store", caller);1010}10111012/*1013 * Downcast ref_store to files_ref_store. Die if ref_store is not a1014 * files_ref_store. required_flags is compared with ref_store's1015 * store_flags to ensure the ref_store has all required capabilities.1016 * "caller" is used in any necessary error messages.1017 */1018static struct files_ref_store *files_downcast(struct ref_store *ref_store,1019 unsigned int required_flags,1020 const char *caller)1021{1022 struct files_ref_store *refs;10231024 if (ref_store->be != &refs_be_files)1025 die("BUG: ref_store is type \"%s\" not \"files\" in %s",1026 ref_store->be->name, caller);10271028 refs = (struct files_ref_store *)ref_store;10291030 if ((refs->store_flags & required_flags) != required_flags)1031 die("BUG: operation %s requires abilities 0x%x, but only have 0x%x",1032 caller, required_flags, refs->store_flags);10331034 return refs;1035}10361037/* The length of a peeled reference line in packed-refs, including EOL: */1038#define PEELED_LINE_LENGTH 4210391040/*1041 * The packed-refs header line that we write out. Perhaps other1042 * traits will be added later. The trailing space is required.1043 */1044static const char PACKED_REFS_HEADER[] =1045 "# pack-refs with: peeled fully-peeled \n";10461047/*1048 * Parse one line from a packed-refs file. Write the SHA1 to sha1.1049 * Return a pointer to the refname within the line (null-terminated),1050 * or NULL if there was a problem.1051 */1052static const char *parse_ref_line(struct strbuf *line, unsigned char *sha1)1053{1054 const char *ref;10551056 /*1057 * 42: the answer to everything.1058 *1059 * In this case, it happens to be the answer to1060 * 40 (length of sha1 hex representation)1061 * +1 (space in between hex and name)1062 * +1 (newline at the end of the line)1063 */1064 if (line->len <= 42)1065 return NULL;10661067 if (get_sha1_hex(line->buf, sha1) < 0)1068 return NULL;1069 if (!isspace(line->buf[40]))1070 return NULL;10711072 ref = line->buf + 41;1073 if (isspace(*ref))1074 return NULL;10751076 if (line->buf[line->len - 1] != '\n')1077 return NULL;1078 line->buf[--line->len] = 0;10791080 return ref;1081}10821083/*1084 * Read f, which is a packed-refs file, into dir.1085 *1086 * A comment line of the form "# pack-refs with: " may contain zero or1087 * more traits. We interpret the traits as follows:1088 *1089 * No traits:1090 *1091 * Probably no references are peeled. But if the file contains a1092 * peeled value for a reference, we will use it.1093 *1094 * peeled:1095 *1096 * References under "refs/tags/", if they *can* be peeled, *are*1097 * peeled in this file. References outside of "refs/tags/" are1098 * probably not peeled even if they could have been, but if we find1099 * a peeled value for such a reference we will use it.1100 *1101 * fully-peeled:1102 *1103 * All references in the file that can be peeled are peeled.1104 * Inversely (and this is more important), any references in the1105 * file for which no peeled value is recorded is not peelable. This1106 * trait should typically be written alongside "peeled" for1107 * compatibility with older clients, but we do not require it1108 * (i.e., "peeled" is a no-op if "fully-peeled" is set).1109 */1110static void read_packed_refs(FILE *f, struct ref_dir *dir)1111{1112 struct ref_entry *last = NULL;1113 struct strbuf line = STRBUF_INIT;1114 enum { PEELED_NONE, PEELED_TAGS, PEELED_FULLY } peeled = PEELED_NONE;11151116 while (strbuf_getwholeline(&line, f, '\n') != EOF) {1117 unsigned char sha1[20];1118 const char *refname;1119 const char *traits;11201121 if (skip_prefix(line.buf, "# pack-refs with:", &traits)) {1122 if (strstr(traits, " fully-peeled "))1123 peeled = PEELED_FULLY;1124 else if (strstr(traits, " peeled "))1125 peeled = PEELED_TAGS;1126 /* perhaps other traits later as well */1127 continue;1128 }11291130 refname = parse_ref_line(&line, sha1);1131 if (refname) {1132 int flag = REF_ISPACKED;11331134 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {1135 if (!refname_is_safe(refname))1136 die("packed refname is dangerous: %s", refname);1137 hashclr(sha1);1138 flag |= REF_BAD_NAME | REF_ISBROKEN;1139 }1140 last = create_ref_entry(refname, sha1, flag, 0);1141 if (peeled == PEELED_FULLY ||1142 (peeled == PEELED_TAGS && starts_with(refname, "refs/tags/")))1143 last->flag |= REF_KNOWS_PEELED;1144 add_ref(dir, last);1145 continue;1146 }1147 if (last &&1148 line.buf[0] == '^' &&1149 line.len == PEELED_LINE_LENGTH &&1150 line.buf[PEELED_LINE_LENGTH - 1] == '\n' &&1151 !get_sha1_hex(line.buf + 1, sha1)) {1152 hashcpy(last->u.value.peeled.hash, sha1);1153 /*1154 * Regardless of what the file header said,1155 * we definitely know the value of *this*1156 * reference:1157 */1158 last->flag |= REF_KNOWS_PEELED;1159 }1160 }11611162 strbuf_release(&line);1163}11641165static const char *files_packed_refs_path(struct files_ref_store *refs)1166{1167 return refs->packed_refs_path;1168}11691170static void files_reflog_path(struct files_ref_store *refs,1171 struct strbuf *sb,1172 const char *refname)1173{1174 if (!refname) {1175 /*1176 * FIXME: of course this is wrong in multi worktree1177 * setting. To be fixed real soon.1178 */1179 strbuf_addf(sb, "%s/logs", refs->gitcommondir);1180 return;1181 }11821183 switch (ref_type(refname)) {1184 case REF_TYPE_PER_WORKTREE:1185 case REF_TYPE_PSEUDOREF:1186 strbuf_addf(sb, "%s/logs/%s", refs->gitdir, refname);1187 break;1188 case REF_TYPE_NORMAL:1189 strbuf_addf(sb, "%s/logs/%s", refs->gitcommondir, refname);1190 break;1191 default:1192 die("BUG: unknown ref type %d of ref %s",1193 ref_type(refname), refname);1194 }1195}11961197static void files_ref_path(struct files_ref_store *refs,1198 struct strbuf *sb,1199 const char *refname)1200{1201 switch (ref_type(refname)) {1202 case REF_TYPE_PER_WORKTREE:1203 case REF_TYPE_PSEUDOREF:1204 strbuf_addf(sb, "%s/%s", refs->gitdir, refname);1205 break;1206 case REF_TYPE_NORMAL:1207 strbuf_addf(sb, "%s/%s", refs->gitcommondir, refname);1208 break;1209 default:1210 die("BUG: unknown ref type %d of ref %s",1211 ref_type(refname), refname);1212 }1213}12141215/*1216 * Get the packed_ref_cache for the specified files_ref_store,1217 * creating it if necessary.1218 */1219static struct packed_ref_cache *get_packed_ref_cache(struct files_ref_store *refs)1220{1221 const char *packed_refs_file = files_packed_refs_path(refs);12221223 if (refs->packed &&1224 !stat_validity_check(&refs->packed->validity, packed_refs_file))1225 clear_packed_ref_cache(refs);12261227 if (!refs->packed) {1228 FILE *f;12291230 refs->packed = xcalloc(1, sizeof(*refs->packed));1231 acquire_packed_ref_cache(refs->packed);1232 refs->packed->root = create_dir_entry(refs, "", 0, 0);1233 f = fopen(packed_refs_file, "r");1234 if (f) {1235 stat_validity_update(&refs->packed->validity, fileno(f));1236 read_packed_refs(f, get_ref_dir(refs->packed->root));1237 fclose(f);1238 }1239 }1240 return refs->packed;1241}12421243static struct ref_dir *get_packed_ref_dir(struct packed_ref_cache *packed_ref_cache)1244{1245 return get_ref_dir(packed_ref_cache->root);1246}12471248static struct ref_dir *get_packed_refs(struct files_ref_store *refs)1249{1250 return get_packed_ref_dir(get_packed_ref_cache(refs));1251}12521253/*1254 * Add a reference to the in-memory packed reference cache. This may1255 * only be called while the packed-refs file is locked (see1256 * lock_packed_refs()). To actually write the packed-refs file, call1257 * commit_packed_refs().1258 */1259static void add_packed_ref(struct files_ref_store *refs,1260 const char *refname, const unsigned char *sha1)1261{1262 struct packed_ref_cache *packed_ref_cache = get_packed_ref_cache(refs);12631264 if (!packed_ref_cache->lock)1265 die("internal error: packed refs not locked");1266 add_ref(get_packed_ref_dir(packed_ref_cache),1267 create_ref_entry(refname, sha1, REF_ISPACKED, 1));1268}12691270/*1271 * Read the loose references from the namespace dirname into dir1272 * (without recursing). dirname must end with '/'. dir must be the1273 * directory entry corresponding to dirname.1274 */1275static void read_loose_refs(const char *dirname, struct ref_dir *dir)1276{1277 struct files_ref_store *refs = dir->ref_store;1278 DIR *d;1279 struct dirent *de;1280 int dirnamelen = strlen(dirname);1281 struct strbuf refname;1282 struct strbuf path = STRBUF_INIT;1283 size_t path_baselen;12841285 files_ref_path(refs, &path, dirname);1286 path_baselen = path.len;12871288 d = opendir(path.buf);1289 if (!d) {1290 strbuf_release(&path);1291 return;1292 }12931294 strbuf_init(&refname, dirnamelen + 257);1295 strbuf_add(&refname, dirname, dirnamelen);12961297 while ((de = readdir(d)) != NULL) {1298 unsigned char sha1[20];1299 struct stat st;1300 int flag;13011302 if (de->d_name[0] == '.')1303 continue;1304 if (ends_with(de->d_name, ".lock"))1305 continue;1306 strbuf_addstr(&refname, de->d_name);1307 strbuf_addstr(&path, de->d_name);1308 if (stat(path.buf, &st) < 0) {1309 ; /* silently ignore */1310 } else if (S_ISDIR(st.st_mode)) {1311 strbuf_addch(&refname, '/');1312 add_entry_to_dir(dir,1313 create_dir_entry(refs, refname.buf,1314 refname.len, 1));1315 } else {1316 if (!refs_resolve_ref_unsafe(&refs->base,1317 refname.buf,1318 RESOLVE_REF_READING,1319 sha1, &flag)) {1320 hashclr(sha1);1321 flag |= REF_ISBROKEN;1322 } else if (is_null_sha1(sha1)) {1323 /*1324 * It is so astronomically unlikely1325 * that NULL_SHA1 is the SHA-1 of an1326 * actual object that we consider its1327 * appearance in a loose reference1328 * file to be repo corruption1329 * (probably due to a software bug).1330 */1331 flag |= REF_ISBROKEN;1332 }13331334 if (check_refname_format(refname.buf,1335 REFNAME_ALLOW_ONELEVEL)) {1336 if (!refname_is_safe(refname.buf))1337 die("loose refname is dangerous: %s", refname.buf);1338 hashclr(sha1);1339 flag |= REF_BAD_NAME | REF_ISBROKEN;1340 }1341 add_entry_to_dir(dir,1342 create_ref_entry(refname.buf, sha1, flag, 0));1343 }1344 strbuf_setlen(&refname, dirnamelen);1345 strbuf_setlen(&path, path_baselen);1346 }1347 strbuf_release(&refname);1348 strbuf_release(&path);1349 closedir(d);1350}13511352static struct ref_dir *get_loose_refs(struct files_ref_store *refs)1353{1354 if (!refs->loose) {1355 /*1356 * Mark the top-level directory complete because we1357 * are about to read the only subdirectory that can1358 * hold references:1359 */1360 refs->loose = create_dir_entry(refs, "", 0, 0);1361 /*1362 * Create an incomplete entry for "refs/":1363 */1364 add_entry_to_dir(get_ref_dir(refs->loose),1365 create_dir_entry(refs, "refs/", 5, 1));1366 }1367 return get_ref_dir(refs->loose);1368}13691370/*1371 * Return the ref_entry for the given refname from the packed1372 * references. If it does not exist, return NULL.1373 */1374static struct ref_entry *get_packed_ref(struct files_ref_store *refs,1375 const char *refname)1376{1377 return find_ref(get_packed_refs(refs), refname);1378}13791380/*1381 * A loose ref file doesn't exist; check for a packed ref.1382 */1383static int resolve_packed_ref(struct files_ref_store *refs,1384 const char *refname,1385 unsigned char *sha1, unsigned int *flags)1386{1387 struct ref_entry *entry;13881389 /*1390 * The loose reference file does not exist; check for a packed1391 * reference.1392 */1393 entry = get_packed_ref(refs, refname);1394 if (entry) {1395 hashcpy(sha1, entry->u.value.oid.hash);1396 *flags |= REF_ISPACKED;1397 return 0;1398 }1399 /* refname is not a packed reference. */1400 return -1;1401}14021403static int files_read_raw_ref(struct ref_store *ref_store,1404 const char *refname, unsigned char *sha1,1405 struct strbuf *referent, unsigned int *type)1406{1407 struct files_ref_store *refs =1408 files_downcast(ref_store, REF_STORE_READ, "read_raw_ref");1409 struct strbuf sb_contents = STRBUF_INIT;1410 struct strbuf sb_path = STRBUF_INIT;1411 const char *path;1412 const char *buf;1413 struct stat st;1414 int fd;1415 int ret = -1;1416 int save_errno;1417 int remaining_retries = 3;14181419 *type = 0;1420 strbuf_reset(&sb_path);14211422 files_ref_path(refs, &sb_path, refname);14231424 path = sb_path.buf;14251426stat_ref:1427 /*1428 * We might have to loop back here to avoid a race1429 * condition: first we lstat() the file, then we try1430 * to read it as a link or as a file. But if somebody1431 * changes the type of the file (file <-> directory1432 * <-> symlink) between the lstat() and reading, then1433 * we don't want to report that as an error but rather1434 * try again starting with the lstat().1435 *1436 * We'll keep a count of the retries, though, just to avoid1437 * any confusing situation sending us into an infinite loop.1438 */14391440 if (remaining_retries-- <= 0)1441 goto out;14421443 if (lstat(path, &st) < 0) {1444 if (errno != ENOENT)1445 goto out;1446 if (resolve_packed_ref(refs, refname, sha1, type)) {1447 errno = ENOENT;1448 goto out;1449 }1450 ret = 0;1451 goto out;1452 }14531454 /* Follow "normalized" - ie "refs/.." symlinks by hand */1455 if (S_ISLNK(st.st_mode)) {1456 strbuf_reset(&sb_contents);1457 if (strbuf_readlink(&sb_contents, path, 0) < 0) {1458 if (errno == ENOENT || errno == EINVAL)1459 /* inconsistent with lstat; retry */1460 goto stat_ref;1461 else1462 goto out;1463 }1464 if (starts_with(sb_contents.buf, "refs/") &&1465 !check_refname_format(sb_contents.buf, 0)) {1466 strbuf_swap(&sb_contents, referent);1467 *type |= REF_ISSYMREF;1468 ret = 0;1469 goto out;1470 }1471 /*1472 * It doesn't look like a refname; fall through to just1473 * treating it like a non-symlink, and reading whatever it1474 * points to.1475 */1476 }14771478 /* Is it a directory? */1479 if (S_ISDIR(st.st_mode)) {1480 /*1481 * Even though there is a directory where the loose1482 * ref is supposed to be, there could still be a1483 * packed ref:1484 */1485 if (resolve_packed_ref(refs, refname, sha1, type)) {1486 errno = EISDIR;1487 goto out;1488 }1489 ret = 0;1490 goto out;1491 }14921493 /*1494 * Anything else, just open it and try to use it as1495 * a ref1496 */1497 fd = open(path, O_RDONLY);1498 if (fd < 0) {1499 if (errno == ENOENT && !S_ISLNK(st.st_mode))1500 /* inconsistent with lstat; retry */1501 goto stat_ref;1502 else1503 goto out;1504 }1505 strbuf_reset(&sb_contents);1506 if (strbuf_read(&sb_contents, fd, 256) < 0) {1507 int save_errno = errno;1508 close(fd);1509 errno = save_errno;1510 goto out;1511 }1512 close(fd);1513 strbuf_rtrim(&sb_contents);1514 buf = sb_contents.buf;1515 if (starts_with(buf, "ref:")) {1516 buf += 4;1517 while (isspace(*buf))1518 buf++;15191520 strbuf_reset(referent);1521 strbuf_addstr(referent, buf);1522 *type |= REF_ISSYMREF;1523 ret = 0;1524 goto out;1525 }15261527 /*1528 * Please note that FETCH_HEAD has additional1529 * data after the sha.1530 */1531 if (get_sha1_hex(buf, sha1) ||1532 (buf[40] != '\0' && !isspace(buf[40]))) {1533 *type |= REF_ISBROKEN;1534 errno = EINVAL;1535 goto out;1536 }15371538 ret = 0;15391540out:1541 save_errno = errno;1542 strbuf_release(&sb_path);1543 strbuf_release(&sb_contents);1544 errno = save_errno;1545 return ret;1546}15471548static void unlock_ref(struct ref_lock *lock)1549{1550 /* Do not free lock->lk -- atexit() still looks at them */1551 if (lock->lk)1552 rollback_lock_file(lock->lk);1553 free(lock->ref_name);1554 free(lock);1555}15561557/*1558 * Lock refname, without following symrefs, and set *lock_p to point1559 * at a newly-allocated lock object. Fill in lock->old_oid, referent,1560 * and type similarly to read_raw_ref().1561 *1562 * The caller must verify that refname is a "safe" reference name (in1563 * the sense of refname_is_safe()) before calling this function.1564 *1565 * If the reference doesn't already exist, verify that refname doesn't1566 * have a D/F conflict with any existing references. extras and skip1567 * are passed to verify_refname_available_dir() for this check.1568 *1569 * If mustexist is not set and the reference is not found or is1570 * broken, lock the reference anyway but clear sha1.1571 *1572 * Return 0 on success. On failure, write an error message to err and1573 * return TRANSACTION_NAME_CONFLICT or TRANSACTION_GENERIC_ERROR.1574 *1575 * Implementation note: This function is basically1576 *1577 * lock reference1578 * read_raw_ref()1579 *1580 * but it includes a lot more code to1581 * - Deal with possible races with other processes1582 * - Avoid calling verify_refname_available_dir() when it can be1583 * avoided, namely if we were successfully able to read the ref1584 * - Generate informative error messages in the case of failure1585 */1586static int lock_raw_ref(struct files_ref_store *refs,1587 const char *refname, int mustexist,1588 const struct string_list *extras,1589 const struct string_list *skip,1590 struct ref_lock **lock_p,1591 struct strbuf *referent,1592 unsigned int *type,1593 struct strbuf *err)1594{1595 struct ref_lock *lock;1596 struct strbuf ref_file = STRBUF_INIT;1597 int attempts_remaining = 3;1598 int ret = TRANSACTION_GENERIC_ERROR;15991600 assert(err);1601 files_assert_main_repository(refs, "lock_raw_ref");16021603 *type = 0;16041605 /* First lock the file so it can't change out from under us. */16061607 *lock_p = lock = xcalloc(1, sizeof(*lock));16081609 lock->ref_name = xstrdup(refname);1610 files_ref_path(refs, &ref_file, refname);16111612retry:1613 switch (safe_create_leading_directories(ref_file.buf)) {1614 case SCLD_OK:1615 break; /* success */1616 case SCLD_EXISTS:1617 /*1618 * Suppose refname is "refs/foo/bar". We just failed1619 * to create the containing directory, "refs/foo",1620 * because there was a non-directory in the way. This1621 * indicates a D/F conflict, probably because of1622 * another reference such as "refs/foo". There is no1623 * reason to expect this error to be transitory.1624 */1625 if (refs_verify_refname_available(&refs->base, refname,1626 extras, skip, err)) {1627 if (mustexist) {1628 /*1629 * To the user the relevant error is1630 * that the "mustexist" reference is1631 * missing:1632 */1633 strbuf_reset(err);1634 strbuf_addf(err, "unable to resolve reference '%s'",1635 refname);1636 } else {1637 /*1638 * The error message set by1639 * verify_refname_available_dir() is OK.1640 */1641 ret = TRANSACTION_NAME_CONFLICT;1642 }1643 } else {1644 /*1645 * The file that is in the way isn't a loose1646 * reference. Report it as a low-level1647 * failure.1648 */1649 strbuf_addf(err, "unable to create lock file %s.lock; "1650 "non-directory in the way",1651 ref_file.buf);1652 }1653 goto error_return;1654 case SCLD_VANISHED:1655 /* Maybe another process was tidying up. Try again. */1656 if (--attempts_remaining > 0)1657 goto retry;1658 /* fall through */1659 default:1660 strbuf_addf(err, "unable to create directory for %s",1661 ref_file.buf);1662 goto error_return;1663 }16641665 if (!lock->lk)1666 lock->lk = xcalloc(1, sizeof(struct lock_file));16671668 if (hold_lock_file_for_update(lock->lk, ref_file.buf, LOCK_NO_DEREF) < 0) {1669 if (errno == ENOENT && --attempts_remaining > 0) {1670 /*1671 * Maybe somebody just deleted one of the1672 * directories leading to ref_file. Try1673 * again:1674 */1675 goto retry;1676 } else {1677 unable_to_lock_message(ref_file.buf, errno, err);1678 goto error_return;1679 }1680 }16811682 /*1683 * Now we hold the lock and can read the reference without1684 * fear that its value will change.1685 */16861687 if (files_read_raw_ref(&refs->base, refname,1688 lock->old_oid.hash, referent, type)) {1689 if (errno == ENOENT) {1690 if (mustexist) {1691 /* Garden variety missing reference. */1692 strbuf_addf(err, "unable to resolve reference '%s'",1693 refname);1694 goto error_return;1695 } else {1696 /*1697 * Reference is missing, but that's OK. We1698 * know that there is not a conflict with1699 * another loose reference because1700 * (supposing that we are trying to lock1701 * reference "refs/foo/bar"):1702 *1703 * - We were successfully able to create1704 * the lockfile refs/foo/bar.lock, so we1705 * know there cannot be a loose reference1706 * named "refs/foo".1707 *1708 * - We got ENOENT and not EISDIR, so we1709 * know that there cannot be a loose1710 * reference named "refs/foo/bar/baz".1711 */1712 }1713 } else if (errno == EISDIR) {1714 /*1715 * There is a directory in the way. It might have1716 * contained references that have been deleted. If1717 * we don't require that the reference already1718 * exists, try to remove the directory so that it1719 * doesn't cause trouble when we want to rename the1720 * lockfile into place later.1721 */1722 if (mustexist) {1723 /* Garden variety missing reference. */1724 strbuf_addf(err, "unable to resolve reference '%s'",1725 refname);1726 goto error_return;1727 } else if (remove_dir_recursively(&ref_file,1728 REMOVE_DIR_EMPTY_ONLY)) {1729 if (verify_refname_available_dir(1730 refname, extras, skip,1731 get_loose_refs(refs),1732 err)) {1733 /*1734 * The error message set by1735 * verify_refname_available() is OK.1736 */1737 ret = TRANSACTION_NAME_CONFLICT;1738 goto error_return;1739 } else {1740 /*1741 * We can't delete the directory,1742 * but we also don't know of any1743 * references that it should1744 * contain.1745 */1746 strbuf_addf(err, "there is a non-empty directory '%s' "1747 "blocking reference '%s'",1748 ref_file.buf, refname);1749 goto error_return;1750 }1751 }1752 } else if (errno == EINVAL && (*type & REF_ISBROKEN)) {1753 strbuf_addf(err, "unable to resolve reference '%s': "1754 "reference broken", refname);1755 goto error_return;1756 } else {1757 strbuf_addf(err, "unable to resolve reference '%s': %s",1758 refname, strerror(errno));1759 goto error_return;1760 }17611762 /*1763 * If the ref did not exist and we are creating it,1764 * make sure there is no existing packed ref whose1765 * name begins with our refname, nor a packed ref1766 * whose name is a proper prefix of our refname.1767 */1768 if (verify_refname_available_dir(1769 refname, extras, skip,1770 get_packed_refs(refs),1771 err)) {1772 goto error_return;1773 }1774 }17751776 ret = 0;1777 goto out;17781779error_return:1780 unlock_ref(lock);1781 *lock_p = NULL;17821783out:1784 strbuf_release(&ref_file);1785 return ret;1786}17871788/*1789 * Peel the entry (if possible) and return its new peel_status. If1790 * repeel is true, re-peel the entry even if there is an old peeled1791 * value that is already stored in it.1792 *1793 * It is OK to call this function with a packed reference entry that1794 * might be stale and might even refer to an object that has since1795 * been garbage-collected. In such a case, if the entry has1796 * REF_KNOWS_PEELED then leave the status unchanged and return1797 * PEEL_PEELED or PEEL_NON_TAG; otherwise, return PEEL_INVALID.1798 */1799static enum peel_status peel_entry(struct ref_entry *entry, int repeel)1800{1801 enum peel_status status;18021803 if (entry->flag & REF_KNOWS_PEELED) {1804 if (repeel) {1805 entry->flag &= ~REF_KNOWS_PEELED;1806 oidclr(&entry->u.value.peeled);1807 } else {1808 return is_null_oid(&entry->u.value.peeled) ?1809 PEEL_NON_TAG : PEEL_PEELED;1810 }1811 }1812 if (entry->flag & REF_ISBROKEN)1813 return PEEL_BROKEN;1814 if (entry->flag & REF_ISSYMREF)1815 return PEEL_IS_SYMREF;18161817 status = peel_object(entry->u.value.oid.hash, entry->u.value.peeled.hash);1818 if (status == PEEL_PEELED || status == PEEL_NON_TAG)1819 entry->flag |= REF_KNOWS_PEELED;1820 return status;1821}18221823static int files_peel_ref(struct ref_store *ref_store,1824 const char *refname, unsigned char *sha1)1825{1826 struct files_ref_store *refs =1827 files_downcast(ref_store, REF_STORE_READ | REF_STORE_ODB,1828 "peel_ref");1829 int flag;1830 unsigned char base[20];18311832 files_assert_main_repository(refs, "peel_ref");18331834 if (current_ref_iter && current_ref_iter->refname == refname) {1835 struct object_id peeled;18361837 if (ref_iterator_peel(current_ref_iter, &peeled))1838 return -1;1839 hashcpy(sha1, peeled.hash);1840 return 0;1841 }18421843 if (read_ref_full(refname, RESOLVE_REF_READING, base, &flag))1844 return -1;18451846 /*1847 * If the reference is packed, read its ref_entry from the1848 * cache in the hope that we already know its peeled value.1849 * We only try this optimization on packed references because1850 * (a) forcing the filling of the loose reference cache could1851 * be expensive and (b) loose references anyway usually do not1852 * have REF_KNOWS_PEELED.1853 */1854 if (flag & REF_ISPACKED) {1855 struct ref_entry *r = get_packed_ref(refs, refname);1856 if (r) {1857 if (peel_entry(r, 0))1858 return -1;1859 hashcpy(sha1, r->u.value.peeled.hash);1860 return 0;1861 }1862 }18631864 return peel_object(base, sha1);1865}18661867struct files_ref_iterator {1868 struct ref_iterator base;18691870 struct packed_ref_cache *packed_ref_cache;1871 struct ref_iterator *iter0;1872 unsigned int flags;1873};18741875static int files_ref_iterator_advance(struct ref_iterator *ref_iterator)1876{1877 struct files_ref_iterator *iter =1878 (struct files_ref_iterator *)ref_iterator;1879 int ok;18801881 while ((ok = ref_iterator_advance(iter->iter0)) == ITER_OK) {1882 if (iter->flags & DO_FOR_EACH_PER_WORKTREE_ONLY &&1883 ref_type(iter->iter0->refname) != REF_TYPE_PER_WORKTREE)1884 continue;18851886 if (!(iter->flags & DO_FOR_EACH_INCLUDE_BROKEN) &&1887 !ref_resolves_to_object(iter->iter0->refname,1888 iter->iter0->oid,1889 iter->iter0->flags))1890 continue;18911892 iter->base.refname = iter->iter0->refname;1893 iter->base.oid = iter->iter0->oid;1894 iter->base.flags = iter->iter0->flags;1895 return ITER_OK;1896 }18971898 iter->iter0 = NULL;1899 if (ref_iterator_abort(ref_iterator) != ITER_DONE)1900 ok = ITER_ERROR;19011902 return ok;1903}19041905static int files_ref_iterator_peel(struct ref_iterator *ref_iterator,1906 struct object_id *peeled)1907{1908 struct files_ref_iterator *iter =1909 (struct files_ref_iterator *)ref_iterator;19101911 return ref_iterator_peel(iter->iter0, peeled);1912}19131914static int files_ref_iterator_abort(struct ref_iterator *ref_iterator)1915{1916 struct files_ref_iterator *iter =1917 (struct files_ref_iterator *)ref_iterator;1918 int ok = ITER_DONE;19191920 if (iter->iter0)1921 ok = ref_iterator_abort(iter->iter0);19221923 release_packed_ref_cache(iter->packed_ref_cache);1924 base_ref_iterator_free(ref_iterator);1925 return ok;1926}19271928static struct ref_iterator_vtable files_ref_iterator_vtable = {1929 files_ref_iterator_advance,1930 files_ref_iterator_peel,1931 files_ref_iterator_abort1932};19331934static struct ref_iterator *files_ref_iterator_begin(1935 struct ref_store *ref_store,1936 const char *prefix, unsigned int flags)1937{1938 struct files_ref_store *refs;1939 struct ref_dir *loose_dir, *packed_dir;1940 struct ref_iterator *loose_iter, *packed_iter;1941 struct files_ref_iterator *iter;1942 struct ref_iterator *ref_iterator;19431944 if (ref_paranoia < 0)1945 ref_paranoia = git_env_bool("GIT_REF_PARANOIA", 0);1946 if (ref_paranoia)1947 flags |= DO_FOR_EACH_INCLUDE_BROKEN;19481949 refs = files_downcast(ref_store,1950 REF_STORE_READ | (ref_paranoia ? 0 : REF_STORE_ODB),1951 "ref_iterator_begin");19521953 iter = xcalloc(1, sizeof(*iter));1954 ref_iterator = &iter->base;1955 base_ref_iterator_init(ref_iterator, &files_ref_iterator_vtable);19561957 /*1958 * We must make sure that all loose refs are read before1959 * accessing the packed-refs file; this avoids a race1960 * condition if loose refs are migrated to the packed-refs1961 * file by a simultaneous process, but our in-memory view is1962 * from before the migration. We ensure this as follows:1963 * First, we call prime_ref_dir(), which pre-reads the loose1964 * references for the subtree into the cache. (If they've1965 * already been read, that's OK; we only need to guarantee1966 * that they're read before the packed refs, not *how much*1967 * before.) After that, we call get_packed_ref_cache(), which1968 * internally checks whether the packed-ref cache is up to1969 * date with what is on disk, and re-reads it if not.1970 */19711972 loose_dir = get_loose_refs(refs);19731974 if (prefix && *prefix)1975 loose_dir = find_containing_dir(loose_dir, prefix, 0);19761977 if (loose_dir) {1978 prime_ref_dir(loose_dir);1979 loose_iter = cache_ref_iterator_begin(loose_dir);1980 } else {1981 /* There's nothing to iterate over. */1982 loose_iter = empty_ref_iterator_begin();1983 }19841985 iter->packed_ref_cache = get_packed_ref_cache(refs);1986 acquire_packed_ref_cache(iter->packed_ref_cache);1987 packed_dir = get_packed_ref_dir(iter->packed_ref_cache);19881989 if (prefix && *prefix)1990 packed_dir = find_containing_dir(packed_dir, prefix, 0);19911992 if (packed_dir) {1993 packed_iter = cache_ref_iterator_begin(packed_dir);1994 } else {1995 /* There's nothing to iterate over. */1996 packed_iter = empty_ref_iterator_begin();1997 }19981999 iter->iter0 = overlay_ref_iterator_begin(loose_iter, packed_iter);2000 iter->flags = flags;20012002 return ref_iterator;2003}20042005/*2006 * Verify that the reference locked by lock has the value old_sha1.2007 * Fail if the reference doesn't exist and mustexist is set. Return 02008 * on success. On error, write an error message to err, set errno, and2009 * return a negative value.2010 */2011static int verify_lock(struct ref_lock *lock,2012 const unsigned char *old_sha1, int mustexist,2013 struct strbuf *err)2014{2015 assert(err);20162017 if (read_ref_full(lock->ref_name,2018 mustexist ? RESOLVE_REF_READING : 0,2019 lock->old_oid.hash, NULL)) {2020 if (old_sha1) {2021 int save_errno = errno;2022 strbuf_addf(err, "can't verify ref '%s'", lock->ref_name);2023 errno = save_errno;2024 return -1;2025 } else {2026 oidclr(&lock->old_oid);2027 return 0;2028 }2029 }2030 if (old_sha1 && hashcmp(lock->old_oid.hash, old_sha1)) {2031 strbuf_addf(err, "ref '%s' is at %s but expected %s",2032 lock->ref_name,2033 oid_to_hex(&lock->old_oid),2034 sha1_to_hex(old_sha1));2035 errno = EBUSY;2036 return -1;2037 }2038 return 0;2039}20402041static int remove_empty_directories(struct strbuf *path)2042{2043 /*2044 * we want to create a file but there is a directory there;2045 * if that is an empty directory (or a directory that contains2046 * only empty directories), remove them.2047 */2048 return remove_dir_recursively(path, REMOVE_DIR_EMPTY_ONLY);2049}20502051static int create_reflock(const char *path, void *cb)2052{2053 struct lock_file *lk = cb;20542055 return hold_lock_file_for_update(lk, path, LOCK_NO_DEREF) < 0 ? -1 : 0;2056}20572058/*2059 * Locks a ref returning the lock on success and NULL on failure.2060 * On failure errno is set to something meaningful.2061 */2062static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs,2063 const char *refname,2064 const unsigned char *old_sha1,2065 const struct string_list *extras,2066 const struct string_list *skip,2067 unsigned int flags, int *type,2068 struct strbuf *err)2069{2070 struct strbuf ref_file = STRBUF_INIT;2071 struct ref_lock *lock;2072 int last_errno = 0;2073 int mustexist = (old_sha1 && !is_null_sha1(old_sha1));2074 int resolve_flags = RESOLVE_REF_NO_RECURSE;2075 int resolved;20762077 files_assert_main_repository(refs, "lock_ref_sha1_basic");2078 assert(err);20792080 lock = xcalloc(1, sizeof(struct ref_lock));20812082 if (mustexist)2083 resolve_flags |= RESOLVE_REF_READING;2084 if (flags & REF_DELETING)2085 resolve_flags |= RESOLVE_REF_ALLOW_BAD_NAME;20862087 files_ref_path(refs, &ref_file, refname);2088 resolved = !!resolve_ref_unsafe(refname, resolve_flags,2089 lock->old_oid.hash, type);2090 if (!resolved && errno == EISDIR) {2091 /*2092 * we are trying to lock foo but we used to2093 * have foo/bar which now does not exist;2094 * it is normal for the empty directory 'foo'2095 * to remain.2096 */2097 if (remove_empty_directories(&ref_file)) {2098 last_errno = errno;2099 if (!verify_refname_available_dir(2100 refname, extras, skip,2101 get_loose_refs(refs), err))2102 strbuf_addf(err, "there are still refs under '%s'",2103 refname);2104 goto error_return;2105 }2106 resolved = !!resolve_ref_unsafe(refname, resolve_flags,2107 lock->old_oid.hash, type);2108 }2109 if (!resolved) {2110 last_errno = errno;2111 if (last_errno != ENOTDIR ||2112 !verify_refname_available_dir(2113 refname, extras, skip,2114 get_loose_refs(refs), err))2115 strbuf_addf(err, "unable to resolve reference '%s': %s",2116 refname, strerror(last_errno));21172118 goto error_return;2119 }21202121 /*2122 * If the ref did not exist and we are creating it, make sure2123 * there is no existing packed ref whose name begins with our2124 * refname, nor a packed ref whose name is a proper prefix of2125 * our refname.2126 */2127 if (is_null_oid(&lock->old_oid) &&2128 verify_refname_available_dir(refname, extras, skip,2129 get_packed_refs(refs),2130 err)) {2131 last_errno = ENOTDIR;2132 goto error_return;2133 }21342135 lock->lk = xcalloc(1, sizeof(struct lock_file));21362137 lock->ref_name = xstrdup(refname);21382139 if (raceproof_create_file(ref_file.buf, create_reflock, lock->lk)) {2140 last_errno = errno;2141 unable_to_lock_message(ref_file.buf, errno, err);2142 goto error_return;2143 }21442145 if (verify_lock(lock, old_sha1, mustexist, err)) {2146 last_errno = errno;2147 goto error_return;2148 }2149 goto out;21502151 error_return:2152 unlock_ref(lock);2153 lock = NULL;21542155 out:2156 strbuf_release(&ref_file);2157 errno = last_errno;2158 return lock;2159}21602161/*2162 * Write an entry to the packed-refs file for the specified refname.2163 * If peeled is non-NULL, write it as the entry's peeled value.2164 */2165static void write_packed_entry(FILE *fh, char *refname, unsigned char *sha1,2166 unsigned char *peeled)2167{2168 fprintf_or_die(fh, "%s %s\n", sha1_to_hex(sha1), refname);2169 if (peeled)2170 fprintf_or_die(fh, "^%s\n", sha1_to_hex(peeled));2171}21722173/*2174 * An each_ref_entry_fn that writes the entry to a packed-refs file.2175 */2176static int write_packed_entry_fn(struct ref_entry *entry, void *cb_data)2177{2178 enum peel_status peel_status = peel_entry(entry, 0);21792180 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)2181 error("internal error: %s is not a valid packed reference!",2182 entry->name);2183 write_packed_entry(cb_data, entry->name, entry->u.value.oid.hash,2184 peel_status == PEEL_PEELED ?2185 entry->u.value.peeled.hash : NULL);2186 return 0;2187}21882189/*2190 * Lock the packed-refs file for writing. Flags is passed to2191 * hold_lock_file_for_update(). Return 0 on success. On errors, set2192 * errno appropriately and return a nonzero value.2193 */2194static int lock_packed_refs(struct files_ref_store *refs, int flags)2195{2196 static int timeout_configured = 0;2197 static int timeout_value = 1000;2198 struct packed_ref_cache *packed_ref_cache;21992200 files_assert_main_repository(refs, "lock_packed_refs");22012202 if (!timeout_configured) {2203 git_config_get_int("core.packedrefstimeout", &timeout_value);2204 timeout_configured = 1;2205 }22062207 if (hold_lock_file_for_update_timeout(2208 &packlock, files_packed_refs_path(refs),2209 flags, timeout_value) < 0)2210 return -1;2211 /*2212 * Get the current packed-refs while holding the lock. If the2213 * packed-refs file has been modified since we last read it,2214 * this will automatically invalidate the cache and re-read2215 * the packed-refs file.2216 */2217 packed_ref_cache = get_packed_ref_cache(refs);2218 packed_ref_cache->lock = &packlock;2219 /* Increment the reference count to prevent it from being freed: */2220 acquire_packed_ref_cache(packed_ref_cache);2221 return 0;2222}22232224/*2225 * Write the current version of the packed refs cache from memory to2226 * disk. The packed-refs file must already be locked for writing (see2227 * lock_packed_refs()). Return zero on success. On errors, set errno2228 * and return a nonzero value2229 */2230static int commit_packed_refs(struct files_ref_store *refs)2231{2232 struct packed_ref_cache *packed_ref_cache =2233 get_packed_ref_cache(refs);2234 int error = 0;2235 int save_errno = 0;2236 FILE *out;22372238 files_assert_main_repository(refs, "commit_packed_refs");22392240 if (!packed_ref_cache->lock)2241 die("internal error: packed-refs not locked");22422243 out = fdopen_lock_file(packed_ref_cache->lock, "w");2244 if (!out)2245 die_errno("unable to fdopen packed-refs descriptor");22462247 fprintf_or_die(out, "%s", PACKED_REFS_HEADER);2248 do_for_each_entry_in_dir(get_packed_ref_dir(packed_ref_cache),2249 0, write_packed_entry_fn, out);22502251 if (commit_lock_file(packed_ref_cache->lock)) {2252 save_errno = errno;2253 error = -1;2254 }2255 packed_ref_cache->lock = NULL;2256 release_packed_ref_cache(packed_ref_cache);2257 errno = save_errno;2258 return error;2259}22602261/*2262 * Rollback the lockfile for the packed-refs file, and discard the2263 * in-memory packed reference cache. (The packed-refs file will be2264 * read anew if it is needed again after this function is called.)2265 */2266static void rollback_packed_refs(struct files_ref_store *refs)2267{2268 struct packed_ref_cache *packed_ref_cache =2269 get_packed_ref_cache(refs);22702271 files_assert_main_repository(refs, "rollback_packed_refs");22722273 if (!packed_ref_cache->lock)2274 die("internal error: packed-refs not locked");2275 rollback_lock_file(packed_ref_cache->lock);2276 packed_ref_cache->lock = NULL;2277 release_packed_ref_cache(packed_ref_cache);2278 clear_packed_ref_cache(refs);2279}22802281struct ref_to_prune {2282 struct ref_to_prune *next;2283 unsigned char sha1[20];2284 char name[FLEX_ARRAY];2285};22862287struct pack_refs_cb_data {2288 unsigned int flags;2289 struct ref_dir *packed_refs;2290 struct ref_to_prune *ref_to_prune;2291};22922293/*2294 * An each_ref_entry_fn that is run over loose references only. If2295 * the loose reference can be packed, add an entry in the packed ref2296 * cache. If the reference should be pruned, also add it to2297 * ref_to_prune in the pack_refs_cb_data.2298 */2299static int pack_if_possible_fn(struct ref_entry *entry, void *cb_data)2300{2301 struct pack_refs_cb_data *cb = cb_data;2302 enum peel_status peel_status;2303 struct ref_entry *packed_entry;2304 int is_tag_ref = starts_with(entry->name, "refs/tags/");23052306 /* Do not pack per-worktree refs: */2307 if (ref_type(entry->name) != REF_TYPE_NORMAL)2308 return 0;23092310 /* ALWAYS pack tags */2311 if (!(cb->flags & PACK_REFS_ALL) && !is_tag_ref)2312 return 0;23132314 /* Do not pack symbolic or broken refs: */2315 if ((entry->flag & REF_ISSYMREF) || !entry_resolves_to_object(entry))2316 return 0;23172318 /* Add a packed ref cache entry equivalent to the loose entry. */2319 peel_status = peel_entry(entry, 1);2320 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)2321 die("internal error peeling reference %s (%s)",2322 entry->name, oid_to_hex(&entry->u.value.oid));2323 packed_entry = find_ref(cb->packed_refs, entry->name);2324 if (packed_entry) {2325 /* Overwrite existing packed entry with info from loose entry */2326 packed_entry->flag = REF_ISPACKED | REF_KNOWS_PEELED;2327 oidcpy(&packed_entry->u.value.oid, &entry->u.value.oid);2328 } else {2329 packed_entry = create_ref_entry(entry->name, entry->u.value.oid.hash,2330 REF_ISPACKED | REF_KNOWS_PEELED, 0);2331 add_ref(cb->packed_refs, packed_entry);2332 }2333 oidcpy(&packed_entry->u.value.peeled, &entry->u.value.peeled);23342335 /* Schedule the loose reference for pruning if requested. */2336 if ((cb->flags & PACK_REFS_PRUNE)) {2337 struct ref_to_prune *n;2338 FLEX_ALLOC_STR(n, name, entry->name);2339 hashcpy(n->sha1, entry->u.value.oid.hash);2340 n->next = cb->ref_to_prune;2341 cb->ref_to_prune = n;2342 }2343 return 0;2344}23452346enum {2347 REMOVE_EMPTY_PARENTS_REF = 0x01,2348 REMOVE_EMPTY_PARENTS_REFLOG = 0x022349};23502351/*2352 * Remove empty parent directories associated with the specified2353 * reference and/or its reflog, but spare [logs/]refs/ and immediate2354 * subdirs. flags is a combination of REMOVE_EMPTY_PARENTS_REF and/or2355 * REMOVE_EMPTY_PARENTS_REFLOG.2356 */2357static void try_remove_empty_parents(struct files_ref_store *refs,2358 const char *refname,2359 unsigned int flags)2360{2361 struct strbuf buf = STRBUF_INIT;2362 struct strbuf sb = STRBUF_INIT;2363 char *p, *q;2364 int i;23652366 strbuf_addstr(&buf, refname);2367 p = buf.buf;2368 for (i = 0; i < 2; i++) { /* refs/{heads,tags,...}/ */2369 while (*p && *p != '/')2370 p++;2371 /* tolerate duplicate slashes; see check_refname_format() */2372 while (*p == '/')2373 p++;2374 }2375 q = buf.buf + buf.len;2376 while (flags & (REMOVE_EMPTY_PARENTS_REF | REMOVE_EMPTY_PARENTS_REFLOG)) {2377 while (q > p && *q != '/')2378 q--;2379 while (q > p && *(q-1) == '/')2380 q--;2381 if (q == p)2382 break;2383 strbuf_setlen(&buf, q - buf.buf);23842385 strbuf_reset(&sb);2386 files_ref_path(refs, &sb, buf.buf);2387 if ((flags & REMOVE_EMPTY_PARENTS_REF) && rmdir(sb.buf))2388 flags &= ~REMOVE_EMPTY_PARENTS_REF;23892390 strbuf_reset(&sb);2391 files_reflog_path(refs, &sb, buf.buf);2392 if ((flags & REMOVE_EMPTY_PARENTS_REFLOG) && rmdir(sb.buf))2393 flags &= ~REMOVE_EMPTY_PARENTS_REFLOG;2394 }2395 strbuf_release(&buf);2396 strbuf_release(&sb);2397}23982399/* make sure nobody touched the ref, and unlink */2400static void prune_ref(struct ref_to_prune *r)2401{2402 struct ref_transaction *transaction;2403 struct strbuf err = STRBUF_INIT;24042405 if (check_refname_format(r->name, 0))2406 return;24072408 transaction = ref_transaction_begin(&err);2409 if (!transaction ||2410 ref_transaction_delete(transaction, r->name, r->sha1,2411 REF_ISPRUNING | REF_NODEREF, NULL, &err) ||2412 ref_transaction_commit(transaction, &err)) {2413 ref_transaction_free(transaction);2414 error("%s", err.buf);2415 strbuf_release(&err);2416 return;2417 }2418 ref_transaction_free(transaction);2419 strbuf_release(&err);2420}24212422static void prune_refs(struct ref_to_prune *r)2423{2424 while (r) {2425 prune_ref(r);2426 r = r->next;2427 }2428}24292430static int files_pack_refs(struct ref_store *ref_store, unsigned int flags)2431{2432 struct files_ref_store *refs =2433 files_downcast(ref_store, REF_STORE_WRITE | REF_STORE_ODB,2434 "pack_refs");2435 struct pack_refs_cb_data cbdata;24362437 memset(&cbdata, 0, sizeof(cbdata));2438 cbdata.flags = flags;24392440 lock_packed_refs(refs, LOCK_DIE_ON_ERROR);2441 cbdata.packed_refs = get_packed_refs(refs);24422443 do_for_each_entry_in_dir(get_loose_refs(refs), 0,2444 pack_if_possible_fn, &cbdata);24452446 if (commit_packed_refs(refs))2447 die_errno("unable to overwrite old ref-pack file");24482449 prune_refs(cbdata.ref_to_prune);2450 return 0;2451}24522453/*2454 * Rewrite the packed-refs file, omitting any refs listed in2455 * 'refnames'. On error, leave packed-refs unchanged, write an error2456 * message to 'err', and return a nonzero value.2457 *2458 * The refs in 'refnames' needn't be sorted. `err` must not be NULL.2459 */2460static int repack_without_refs(struct files_ref_store *refs,2461 struct string_list *refnames, struct strbuf *err)2462{2463 struct ref_dir *packed;2464 struct string_list_item *refname;2465 int ret, needs_repacking = 0, removed = 0;24662467 files_assert_main_repository(refs, "repack_without_refs");2468 assert(err);24692470 /* Look for a packed ref */2471 for_each_string_list_item(refname, refnames) {2472 if (get_packed_ref(refs, refname->string)) {2473 needs_repacking = 1;2474 break;2475 }2476 }24772478 /* Avoid locking if we have nothing to do */2479 if (!needs_repacking)2480 return 0; /* no refname exists in packed refs */24812482 if (lock_packed_refs(refs, 0)) {2483 unable_to_lock_message(files_packed_refs_path(refs), errno, err);2484 return -1;2485 }2486 packed = get_packed_refs(refs);24872488 /* Remove refnames from the cache */2489 for_each_string_list_item(refname, refnames)2490 if (remove_entry(packed, refname->string) != -1)2491 removed = 1;2492 if (!removed) {2493 /*2494 * All packed entries disappeared while we were2495 * acquiring the lock.2496 */2497 rollback_packed_refs(refs);2498 return 0;2499 }25002501 /* Write what remains */2502 ret = commit_packed_refs(refs);2503 if (ret)2504 strbuf_addf(err, "unable to overwrite old ref-pack file: %s",2505 strerror(errno));2506 return ret;2507}25082509static int files_delete_refs(struct ref_store *ref_store,2510 struct string_list *refnames, unsigned int flags)2511{2512 struct files_ref_store *refs =2513 files_downcast(ref_store, REF_STORE_WRITE, "delete_refs");2514 struct strbuf err = STRBUF_INIT;2515 int i, result = 0;25162517 if (!refnames->nr)2518 return 0;25192520 result = repack_without_refs(refs, refnames, &err);2521 if (result) {2522 /*2523 * If we failed to rewrite the packed-refs file, then2524 * it is unsafe to try to remove loose refs, because2525 * doing so might expose an obsolete packed value for2526 * a reference that might even point at an object that2527 * has been garbage collected.2528 */2529 if (refnames->nr == 1)2530 error(_("could not delete reference %s: %s"),2531 refnames->items[0].string, err.buf);2532 else2533 error(_("could not delete references: %s"), err.buf);25342535 goto out;2536 }25372538 for (i = 0; i < refnames->nr; i++) {2539 const char *refname = refnames->items[i].string;25402541 if (delete_ref(NULL, refname, NULL, flags))2542 result |= error(_("could not remove reference %s"), refname);2543 }25442545out:2546 strbuf_release(&err);2547 return result;2548}25492550/*2551 * People using contrib's git-new-workdir have .git/logs/refs ->2552 * /some/other/path/.git/logs/refs, and that may live on another device.2553 *2554 * IOW, to avoid cross device rename errors, the temporary renamed log must2555 * live into logs/refs.2556 */2557#define TMP_RENAMED_LOG "refs/.tmp-renamed-log"25582559struct rename_cb {2560 const char *tmp_renamed_log;2561 int true_errno;2562};25632564static int rename_tmp_log_callback(const char *path, void *cb_data)2565{2566 struct rename_cb *cb = cb_data;25672568 if (rename(cb->tmp_renamed_log, path)) {2569 /*2570 * rename(a, b) when b is an existing directory ought2571 * to result in ISDIR, but Solaris 5.8 gives ENOTDIR.2572 * Sheesh. Record the true errno for error reporting,2573 * but report EISDIR to raceproof_create_file() so2574 * that it knows to retry.2575 */2576 cb->true_errno = errno;2577 if (errno == ENOTDIR)2578 errno = EISDIR;2579 return -1;2580 } else {2581 return 0;2582 }2583}25842585static int rename_tmp_log(struct files_ref_store *refs, const char *newrefname)2586{2587 struct strbuf path = STRBUF_INIT;2588 struct strbuf tmp = STRBUF_INIT;2589 struct rename_cb cb;2590 int ret;25912592 files_reflog_path(refs, &path, newrefname);2593 files_reflog_path(refs, &tmp, TMP_RENAMED_LOG);2594 cb.tmp_renamed_log = tmp.buf;2595 ret = raceproof_create_file(path.buf, rename_tmp_log_callback, &cb);2596 if (ret) {2597 if (errno == EISDIR)2598 error("directory not empty: %s", path.buf);2599 else2600 error("unable to move logfile %s to %s: %s",2601 tmp.buf, path.buf,2602 strerror(cb.true_errno));2603 }26042605 strbuf_release(&path);2606 strbuf_release(&tmp);2607 return ret;2608}26092610static int files_verify_refname_available(struct ref_store *ref_store,2611 const char *newname,2612 const struct string_list *extras,2613 const struct string_list *skip,2614 struct strbuf *err)2615{2616 struct files_ref_store *refs =2617 files_downcast(ref_store, REF_STORE_READ, "verify_refname_available");2618 struct ref_dir *packed_refs = get_packed_refs(refs);2619 struct ref_dir *loose_refs = get_loose_refs(refs);26202621 if (verify_refname_available_dir(newname, extras, skip,2622 packed_refs, err) ||2623 verify_refname_available_dir(newname, extras, skip,2624 loose_refs, err))2625 return -1;26262627 return 0;2628}26292630static int write_ref_to_lockfile(struct ref_lock *lock,2631 const unsigned char *sha1, struct strbuf *err);2632static int commit_ref_update(struct files_ref_store *refs,2633 struct ref_lock *lock,2634 const unsigned char *sha1, const char *logmsg,2635 struct strbuf *err);26362637static int files_rename_ref(struct ref_store *ref_store,2638 const char *oldrefname, const char *newrefname,2639 const char *logmsg)2640{2641 struct files_ref_store *refs =2642 files_downcast(ref_store, REF_STORE_WRITE, "rename_ref");2643 unsigned char sha1[20], orig_sha1[20];2644 int flag = 0, logmoved = 0;2645 struct ref_lock *lock;2646 struct stat loginfo;2647 struct strbuf sb_oldref = STRBUF_INIT;2648 struct strbuf sb_newref = STRBUF_INIT;2649 struct strbuf tmp_renamed_log = STRBUF_INIT;2650 int log, ret;2651 struct strbuf err = STRBUF_INIT;26522653 files_reflog_path(refs, &sb_oldref, oldrefname);2654 files_reflog_path(refs, &sb_newref, newrefname);2655 files_reflog_path(refs, &tmp_renamed_log, TMP_RENAMED_LOG);26562657 log = !lstat(sb_oldref.buf, &loginfo);2658 if (log && S_ISLNK(loginfo.st_mode)) {2659 ret = error("reflog for %s is a symlink", oldrefname);2660 goto out;2661 }26622663 if (!resolve_ref_unsafe(oldrefname, RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,2664 orig_sha1, &flag)) {2665 ret = error("refname %s not found", oldrefname);2666 goto out;2667 }26682669 if (flag & REF_ISSYMREF) {2670 ret = error("refname %s is a symbolic ref, renaming it is not supported",2671 oldrefname);2672 goto out;2673 }2674 if (!refs_rename_ref_available(&refs->base, oldrefname, newrefname)) {2675 ret = 1;2676 goto out;2677 }26782679 if (log && rename(sb_oldref.buf, tmp_renamed_log.buf)) {2680 ret = error("unable to move logfile logs/%s to logs/"TMP_RENAMED_LOG": %s",2681 oldrefname, strerror(errno));2682 goto out;2683 }26842685 if (delete_ref(logmsg, oldrefname, orig_sha1, REF_NODEREF)) {2686 error("unable to delete old %s", oldrefname);2687 goto rollback;2688 }26892690 /*2691 * Since we are doing a shallow lookup, sha1 is not the2692 * correct value to pass to delete_ref as old_sha1. But that2693 * doesn't matter, because an old_sha1 check wouldn't add to2694 * the safety anyway; we want to delete the reference whatever2695 * its current value.2696 */2697 if (!read_ref_full(newrefname, RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,2698 sha1, NULL) &&2699 delete_ref(NULL, newrefname, NULL, REF_NODEREF)) {2700 if (errno == EISDIR) {2701 struct strbuf path = STRBUF_INIT;2702 int result;27032704 files_ref_path(refs, &path, newrefname);2705 result = remove_empty_directories(&path);2706 strbuf_release(&path);27072708 if (result) {2709 error("Directory not empty: %s", newrefname);2710 goto rollback;2711 }2712 } else {2713 error("unable to delete existing %s", newrefname);2714 goto rollback;2715 }2716 }27172718 if (log && rename_tmp_log(refs, newrefname))2719 goto rollback;27202721 logmoved = log;27222723 lock = lock_ref_sha1_basic(refs, newrefname, NULL, NULL, NULL,2724 REF_NODEREF, NULL, &err);2725 if (!lock) {2726 error("unable to rename '%s' to '%s': %s", oldrefname, newrefname, err.buf);2727 strbuf_release(&err);2728 goto rollback;2729 }2730 hashcpy(lock->old_oid.hash, orig_sha1);27312732 if (write_ref_to_lockfile(lock, orig_sha1, &err) ||2733 commit_ref_update(refs, lock, orig_sha1, logmsg, &err)) {2734 error("unable to write current sha1 into %s: %s", newrefname, err.buf);2735 strbuf_release(&err);2736 goto rollback;2737 }27382739 ret = 0;2740 goto out;27412742 rollback:2743 lock = lock_ref_sha1_basic(refs, oldrefname, NULL, NULL, NULL,2744 REF_NODEREF, NULL, &err);2745 if (!lock) {2746 error("unable to lock %s for rollback: %s", oldrefname, err.buf);2747 strbuf_release(&err);2748 goto rollbacklog;2749 }27502751 flag = log_all_ref_updates;2752 log_all_ref_updates = LOG_REFS_NONE;2753 if (write_ref_to_lockfile(lock, orig_sha1, &err) ||2754 commit_ref_update(refs, lock, orig_sha1, NULL, &err)) {2755 error("unable to write current sha1 into %s: %s", oldrefname, err.buf);2756 strbuf_release(&err);2757 }2758 log_all_ref_updates = flag;27592760 rollbacklog:2761 if (logmoved && rename(sb_newref.buf, sb_oldref.buf))2762 error("unable to restore logfile %s from %s: %s",2763 oldrefname, newrefname, strerror(errno));2764 if (!logmoved && log &&2765 rename(tmp_renamed_log.buf, sb_oldref.buf))2766 error("unable to restore logfile %s from logs/"TMP_RENAMED_LOG": %s",2767 oldrefname, strerror(errno));2768 ret = 1;2769 out:2770 strbuf_release(&sb_newref);2771 strbuf_release(&sb_oldref);2772 strbuf_release(&tmp_renamed_log);27732774 return ret;2775}27762777static int close_ref(struct ref_lock *lock)2778{2779 if (close_lock_file(lock->lk))2780 return -1;2781 return 0;2782}27832784static int commit_ref(struct ref_lock *lock)2785{2786 char *path = get_locked_file_path(lock->lk);2787 struct stat st;27882789 if (!lstat(path, &st) && S_ISDIR(st.st_mode)) {2790 /*2791 * There is a directory at the path we want to rename2792 * the lockfile to. Hopefully it is empty; try to2793 * delete it.2794 */2795 size_t len = strlen(path);2796 struct strbuf sb_path = STRBUF_INIT;27972798 strbuf_attach(&sb_path, path, len, len);27992800 /*2801 * If this fails, commit_lock_file() will also fail2802 * and will report the problem.2803 */2804 remove_empty_directories(&sb_path);2805 strbuf_release(&sb_path);2806 } else {2807 free(path);2808 }28092810 if (commit_lock_file(lock->lk))2811 return -1;2812 return 0;2813}28142815static int open_or_create_logfile(const char *path, void *cb)2816{2817 int *fd = cb;28182819 *fd = open(path, O_APPEND | O_WRONLY | O_CREAT, 0666);2820 return (*fd < 0) ? -1 : 0;2821}28222823/*2824 * Create a reflog for a ref. If force_create = 0, only create the2825 * reflog for certain refs (those for which should_autocreate_reflog2826 * returns non-zero). Otherwise, create it regardless of the reference2827 * name. If the logfile already existed or was created, return 0 and2828 * set *logfd to the file descriptor opened for appending to the file.2829 * If no logfile exists and we decided not to create one, return 0 and2830 * set *logfd to -1. On failure, fill in *err, set *logfd to -1, and2831 * return -1.2832 */2833static int log_ref_setup(struct files_ref_store *refs,2834 const char *refname, int force_create,2835 int *logfd, struct strbuf *err)2836{2837 struct strbuf logfile_sb = STRBUF_INIT;2838 char *logfile;28392840 files_reflog_path(refs, &logfile_sb, refname);2841 logfile = strbuf_detach(&logfile_sb, NULL);28422843 if (force_create || should_autocreate_reflog(refname)) {2844 if (raceproof_create_file(logfile, open_or_create_logfile, logfd)) {2845 if (errno == ENOENT)2846 strbuf_addf(err, "unable to create directory for '%s': "2847 "%s", logfile, strerror(errno));2848 else if (errno == EISDIR)2849 strbuf_addf(err, "there are still logs under '%s'",2850 logfile);2851 else2852 strbuf_addf(err, "unable to append to '%s': %s",2853 logfile, strerror(errno));28542855 goto error;2856 }2857 } else {2858 *logfd = open(logfile, O_APPEND | O_WRONLY, 0666);2859 if (*logfd < 0) {2860 if (errno == ENOENT || errno == EISDIR) {2861 /*2862 * The logfile doesn't already exist,2863 * but that is not an error; it only2864 * means that we won't write log2865 * entries to it.2866 */2867 ;2868 } else {2869 strbuf_addf(err, "unable to append to '%s': %s",2870 logfile, strerror(errno));2871 goto error;2872 }2873 }2874 }28752876 if (*logfd >= 0)2877 adjust_shared_perm(logfile);28782879 free(logfile);2880 return 0;28812882error:2883 free(logfile);2884 return -1;2885}28862887static int files_create_reflog(struct ref_store *ref_store,2888 const char *refname, int force_create,2889 struct strbuf *err)2890{2891 struct files_ref_store *refs =2892 files_downcast(ref_store, REF_STORE_WRITE, "create_reflog");2893 int fd;28942895 if (log_ref_setup(refs, refname, force_create, &fd, err))2896 return -1;28972898 if (fd >= 0)2899 close(fd);29002901 return 0;2902}29032904static int log_ref_write_fd(int fd, const unsigned char *old_sha1,2905 const unsigned char *new_sha1,2906 const char *committer, const char *msg)2907{2908 int msglen, written;2909 unsigned maxlen, len;2910 char *logrec;29112912 msglen = msg ? strlen(msg) : 0;2913 maxlen = strlen(committer) + msglen + 100;2914 logrec = xmalloc(maxlen);2915 len = xsnprintf(logrec, maxlen, "%s %s %s\n",2916 sha1_to_hex(old_sha1),2917 sha1_to_hex(new_sha1),2918 committer);2919 if (msglen)2920 len += copy_reflog_msg(logrec + len - 1, msg) - 1;29212922 written = len <= maxlen ? write_in_full(fd, logrec, len) : -1;2923 free(logrec);2924 if (written != len)2925 return -1;29262927 return 0;2928}29292930static int files_log_ref_write(struct files_ref_store *refs,2931 const char *refname, const unsigned char *old_sha1,2932 const unsigned char *new_sha1, const char *msg,2933 int flags, struct strbuf *err)2934{2935 int logfd, result;29362937 if (log_all_ref_updates == LOG_REFS_UNSET)2938 log_all_ref_updates = is_bare_repository() ? LOG_REFS_NONE : LOG_REFS_NORMAL;29392940 result = log_ref_setup(refs, refname,2941 flags & REF_FORCE_CREATE_REFLOG,2942 &logfd, err);29432944 if (result)2945 return result;29462947 if (logfd < 0)2948 return 0;2949 result = log_ref_write_fd(logfd, old_sha1, new_sha1,2950 git_committer_info(0), msg);2951 if (result) {2952 struct strbuf sb = STRBUF_INIT;2953 int save_errno = errno;29542955 files_reflog_path(refs, &sb, refname);2956 strbuf_addf(err, "unable to append to '%s': %s",2957 sb.buf, strerror(save_errno));2958 strbuf_release(&sb);2959 close(logfd);2960 return -1;2961 }2962 if (close(logfd)) {2963 struct strbuf sb = STRBUF_INIT;2964 int save_errno = errno;29652966 files_reflog_path(refs, &sb, refname);2967 strbuf_addf(err, "unable to append to '%s': %s",2968 sb.buf, strerror(save_errno));2969 strbuf_release(&sb);2970 return -1;2971 }2972 return 0;2973}29742975/*2976 * Write sha1 into the open lockfile, then close the lockfile. On2977 * errors, rollback the lockfile, fill in *err and2978 * return -1.2979 */2980static int write_ref_to_lockfile(struct ref_lock *lock,2981 const unsigned char *sha1, struct strbuf *err)2982{2983 static char term = '\n';2984 struct object *o;2985 int fd;29862987 o = parse_object(sha1);2988 if (!o) {2989 strbuf_addf(err,2990 "trying to write ref '%s' with nonexistent object %s",2991 lock->ref_name, sha1_to_hex(sha1));2992 unlock_ref(lock);2993 return -1;2994 }2995 if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {2996 strbuf_addf(err,2997 "trying to write non-commit object %s to branch '%s'",2998 sha1_to_hex(sha1), lock->ref_name);2999 unlock_ref(lock);3000 return -1;3001 }3002 fd = get_lock_file_fd(lock->lk);3003 if (write_in_full(fd, sha1_to_hex(sha1), 40) != 40 ||3004 write_in_full(fd, &term, 1) != 1 ||3005 close_ref(lock) < 0) {3006 strbuf_addf(err,3007 "couldn't write '%s'", get_lock_file_path(lock->lk));3008 unlock_ref(lock);3009 return -1;3010 }3011 return 0;3012}30133014/*3015 * Commit a change to a loose reference that has already been written3016 * to the loose reference lockfile. Also update the reflogs if3017 * necessary, using the specified lockmsg (which can be NULL).3018 */3019static int commit_ref_update(struct files_ref_store *refs,3020 struct ref_lock *lock,3021 const unsigned char *sha1, const char *logmsg,3022 struct strbuf *err)3023{3024 files_assert_main_repository(refs, "commit_ref_update");30253026 clear_loose_ref_cache(refs);3027 if (files_log_ref_write(refs, lock->ref_name,3028 lock->old_oid.hash, sha1,3029 logmsg, 0, err)) {3030 char *old_msg = strbuf_detach(err, NULL);3031 strbuf_addf(err, "cannot update the ref '%s': %s",3032 lock->ref_name, old_msg);3033 free(old_msg);3034 unlock_ref(lock);3035 return -1;3036 }30373038 if (strcmp(lock->ref_name, "HEAD") != 0) {3039 /*3040 * Special hack: If a branch is updated directly and HEAD3041 * points to it (may happen on the remote side of a push3042 * for example) then logically the HEAD reflog should be3043 * updated too.3044 * A generic solution implies reverse symref information,3045 * but finding all symrefs pointing to the given branch3046 * would be rather costly for this rare event (the direct3047 * update of a branch) to be worth it. So let's cheat and3048 * check with HEAD only which should cover 99% of all usage3049 * scenarios (even 100% of the default ones).3050 */3051 unsigned char head_sha1[20];3052 int head_flag;3053 const char *head_ref;30543055 head_ref = resolve_ref_unsafe("HEAD", RESOLVE_REF_READING,3056 head_sha1, &head_flag);3057 if (head_ref && (head_flag & REF_ISSYMREF) &&3058 !strcmp(head_ref, lock->ref_name)) {3059 struct strbuf log_err = STRBUF_INIT;3060 if (files_log_ref_write(refs, "HEAD",3061 lock->old_oid.hash, sha1,3062 logmsg, 0, &log_err)) {3063 error("%s", log_err.buf);3064 strbuf_release(&log_err);3065 }3066 }3067 }30683069 if (commit_ref(lock)) {3070 strbuf_addf(err, "couldn't set '%s'", lock->ref_name);3071 unlock_ref(lock);3072 return -1;3073 }30743075 unlock_ref(lock);3076 return 0;3077}30783079static int create_ref_symlink(struct ref_lock *lock, const char *target)3080{3081 int ret = -1;3082#ifndef NO_SYMLINK_HEAD3083 char *ref_path = get_locked_file_path(lock->lk);3084 unlink(ref_path);3085 ret = symlink(target, ref_path);3086 free(ref_path);30873088 if (ret)3089 fprintf(stderr, "no symlink - falling back to symbolic ref\n");3090#endif3091 return ret;3092}30933094static void update_symref_reflog(struct files_ref_store *refs,3095 struct ref_lock *lock, const char *refname,3096 const char *target, const char *logmsg)3097{3098 struct strbuf err = STRBUF_INIT;3099 unsigned char new_sha1[20];3100 if (logmsg && !read_ref(target, new_sha1) &&3101 files_log_ref_write(refs, refname, lock->old_oid.hash,3102 new_sha1, logmsg, 0, &err)) {3103 error("%s", err.buf);3104 strbuf_release(&err);3105 }3106}31073108static int create_symref_locked(struct files_ref_store *refs,3109 struct ref_lock *lock, const char *refname,3110 const char *target, const char *logmsg)3111{3112 if (prefer_symlink_refs && !create_ref_symlink(lock, target)) {3113 update_symref_reflog(refs, lock, refname, target, logmsg);3114 return 0;3115 }31163117 if (!fdopen_lock_file(lock->lk, "w"))3118 return error("unable to fdopen %s: %s",3119 lock->lk->tempfile.filename.buf, strerror(errno));31203121 update_symref_reflog(refs, lock, refname, target, logmsg);31223123 /* no error check; commit_ref will check ferror */3124 fprintf(lock->lk->tempfile.fp, "ref: %s\n", target);3125 if (commit_ref(lock) < 0)3126 return error("unable to write symref for %s: %s", refname,3127 strerror(errno));3128 return 0;3129}31303131static int files_create_symref(struct ref_store *ref_store,3132 const char *refname, const char *target,3133 const char *logmsg)3134{3135 struct files_ref_store *refs =3136 files_downcast(ref_store, REF_STORE_WRITE, "create_symref");3137 struct strbuf err = STRBUF_INIT;3138 struct ref_lock *lock;3139 int ret;31403141 lock = lock_ref_sha1_basic(refs, refname, NULL,3142 NULL, NULL, REF_NODEREF, NULL,3143 &err);3144 if (!lock) {3145 error("%s", err.buf);3146 strbuf_release(&err);3147 return -1;3148 }31493150 ret = create_symref_locked(refs, lock, refname, target, logmsg);3151 unlock_ref(lock);3152 return ret;3153}31543155int set_worktree_head_symref(const char *gitdir, const char *target, const char *logmsg)3156{3157 /*3158 * FIXME: this obviously will not work well for future refs3159 * backends. This function needs to die.3160 */3161 struct files_ref_store *refs =3162 files_downcast(get_main_ref_store(),3163 REF_STORE_WRITE,3164 "set_head_symref");31653166 static struct lock_file head_lock;3167 struct ref_lock *lock;3168 struct strbuf head_path = STRBUF_INIT;3169 const char *head_rel;3170 int ret;31713172 strbuf_addf(&head_path, "%s/HEAD", absolute_path(gitdir));3173 if (hold_lock_file_for_update(&head_lock, head_path.buf,3174 LOCK_NO_DEREF) < 0) {3175 struct strbuf err = STRBUF_INIT;3176 unable_to_lock_message(head_path.buf, errno, &err);3177 error("%s", err.buf);3178 strbuf_release(&err);3179 strbuf_release(&head_path);3180 return -1;3181 }31823183 /* head_rel will be "HEAD" for the main tree, "worktrees/wt/HEAD" for3184 linked trees */3185 head_rel = remove_leading_path(head_path.buf,3186 absolute_path(get_git_common_dir()));3187 /* to make use of create_symref_locked(), initialize ref_lock */3188 lock = xcalloc(1, sizeof(struct ref_lock));3189 lock->lk = &head_lock;3190 lock->ref_name = xstrdup(head_rel);31913192 ret = create_symref_locked(refs, lock, head_rel, target, logmsg);31933194 unlock_ref(lock); /* will free lock */3195 strbuf_release(&head_path);3196 return ret;3197}31983199static int files_reflog_exists(struct ref_store *ref_store,3200 const char *refname)3201{3202 struct files_ref_store *refs =3203 files_downcast(ref_store, REF_STORE_READ, "reflog_exists");3204 struct strbuf sb = STRBUF_INIT;3205 struct stat st;3206 int ret;32073208 files_reflog_path(refs, &sb, refname);3209 ret = !lstat(sb.buf, &st) && S_ISREG(st.st_mode);3210 strbuf_release(&sb);3211 return ret;3212}32133214static int files_delete_reflog(struct ref_store *ref_store,3215 const char *refname)3216{3217 struct files_ref_store *refs =3218 files_downcast(ref_store, REF_STORE_WRITE, "delete_reflog");3219 struct strbuf sb = STRBUF_INIT;3220 int ret;32213222 files_reflog_path(refs, &sb, refname);3223 ret = remove_path(sb.buf);3224 strbuf_release(&sb);3225 return ret;3226}32273228static int show_one_reflog_ent(struct strbuf *sb, each_reflog_ent_fn fn, void *cb_data)3229{3230 struct object_id ooid, noid;3231 char *email_end, *message;3232 unsigned long timestamp;3233 int tz;3234 const char *p = sb->buf;32353236 /* old SP new SP name <email> SP time TAB msg LF */3237 if (!sb->len || sb->buf[sb->len - 1] != '\n' ||3238 parse_oid_hex(p, &ooid, &p) || *p++ != ' ' ||3239 parse_oid_hex(p, &noid, &p) || *p++ != ' ' ||3240 !(email_end = strchr(p, '>')) ||3241 email_end[1] != ' ' ||3242 !(timestamp = strtoul(email_end + 2, &message, 10)) ||3243 !message || message[0] != ' ' ||3244 (message[1] != '+' && message[1] != '-') ||3245 !isdigit(message[2]) || !isdigit(message[3]) ||3246 !isdigit(message[4]) || !isdigit(message[5]))3247 return 0; /* corrupt? */3248 email_end[1] = '\0';3249 tz = strtol(message + 1, NULL, 10);3250 if (message[6] != '\t')3251 message += 6;3252 else3253 message += 7;3254 return fn(&ooid, &noid, p, timestamp, tz, message, cb_data);3255}32563257static char *find_beginning_of_line(char *bob, char *scan)3258{3259 while (bob < scan && *(--scan) != '\n')3260 ; /* keep scanning backwards */3261 /*3262 * Return either beginning of the buffer, or LF at the end of3263 * the previous line.3264 */3265 return scan;3266}32673268static int files_for_each_reflog_ent_reverse(struct ref_store *ref_store,3269 const char *refname,3270 each_reflog_ent_fn fn,3271 void *cb_data)3272{3273 struct files_ref_store *refs =3274 files_downcast(ref_store, REF_STORE_READ,3275 "for_each_reflog_ent_reverse");3276 struct strbuf sb = STRBUF_INIT;3277 FILE *logfp;3278 long pos;3279 int ret = 0, at_tail = 1;32803281 files_reflog_path(refs, &sb, refname);3282 logfp = fopen(sb.buf, "r");3283 strbuf_release(&sb);3284 if (!logfp)3285 return -1;32863287 /* Jump to the end */3288 if (fseek(logfp, 0, SEEK_END) < 0)3289 return error("cannot seek back reflog for %s: %s",3290 refname, strerror(errno));3291 pos = ftell(logfp);3292 while (!ret && 0 < pos) {3293 int cnt;3294 size_t nread;3295 char buf[BUFSIZ];3296 char *endp, *scanp;32973298 /* Fill next block from the end */3299 cnt = (sizeof(buf) < pos) ? sizeof(buf) : pos;3300 if (fseek(logfp, pos - cnt, SEEK_SET))3301 return error("cannot seek back reflog for %s: %s",3302 refname, strerror(errno));3303 nread = fread(buf, cnt, 1, logfp);3304 if (nread != 1)3305 return error("cannot read %d bytes from reflog for %s: %s",3306 cnt, refname, strerror(errno));3307 pos -= cnt;33083309 scanp = endp = buf + cnt;3310 if (at_tail && scanp[-1] == '\n')3311 /* Looking at the final LF at the end of the file */3312 scanp--;3313 at_tail = 0;33143315 while (buf < scanp) {3316 /*3317 * terminating LF of the previous line, or the beginning3318 * of the buffer.3319 */3320 char *bp;33213322 bp = find_beginning_of_line(buf, scanp);33233324 if (*bp == '\n') {3325 /*3326 * The newline is the end of the previous line,3327 * so we know we have complete line starting3328 * at (bp + 1). Prefix it onto any prior data3329 * we collected for the line and process it.3330 */3331 strbuf_splice(&sb, 0, 0, bp + 1, endp - (bp + 1));3332 scanp = bp;3333 endp = bp + 1;3334 ret = show_one_reflog_ent(&sb, fn, cb_data);3335 strbuf_reset(&sb);3336 if (ret)3337 break;3338 } else if (!pos) {3339 /*3340 * We are at the start of the buffer, and the3341 * start of the file; there is no previous3342 * line, and we have everything for this one.3343 * Process it, and we can end the loop.3344 */3345 strbuf_splice(&sb, 0, 0, buf, endp - buf);3346 ret = show_one_reflog_ent(&sb, fn, cb_data);3347 strbuf_reset(&sb);3348 break;3349 }33503351 if (bp == buf) {3352 /*3353 * We are at the start of the buffer, and there3354 * is more file to read backwards. Which means3355 * we are in the middle of a line. Note that we3356 * may get here even if *bp was a newline; that3357 * just means we are at the exact end of the3358 * previous line, rather than some spot in the3359 * middle.3360 *3361 * Save away what we have to be combined with3362 * the data from the next read.3363 */3364 strbuf_splice(&sb, 0, 0, buf, endp - buf);3365 break;3366 }3367 }33683369 }3370 if (!ret && sb.len)3371 die("BUG: reverse reflog parser had leftover data");33723373 fclose(logfp);3374 strbuf_release(&sb);3375 return ret;3376}33773378static int files_for_each_reflog_ent(struct ref_store *ref_store,3379 const char *refname,3380 each_reflog_ent_fn fn, void *cb_data)3381{3382 struct files_ref_store *refs =3383 files_downcast(ref_store, REF_STORE_READ,3384 "for_each_reflog_ent");3385 FILE *logfp;3386 struct strbuf sb = STRBUF_INIT;3387 int ret = 0;33883389 files_reflog_path(refs, &sb, refname);3390 logfp = fopen(sb.buf, "r");3391 strbuf_release(&sb);3392 if (!logfp)3393 return -1;33943395 while (!ret && !strbuf_getwholeline(&sb, logfp, '\n'))3396 ret = show_one_reflog_ent(&sb, fn, cb_data);3397 fclose(logfp);3398 strbuf_release(&sb);3399 return ret;3400}34013402struct files_reflog_iterator {3403 struct ref_iterator base;34043405 struct dir_iterator *dir_iterator;3406 struct object_id oid;3407};34083409static int files_reflog_iterator_advance(struct ref_iterator *ref_iterator)3410{3411 struct files_reflog_iterator *iter =3412 (struct files_reflog_iterator *)ref_iterator;3413 struct dir_iterator *diter = iter->dir_iterator;3414 int ok;34153416 while ((ok = dir_iterator_advance(diter)) == ITER_OK) {3417 int flags;34183419 if (!S_ISREG(diter->st.st_mode))3420 continue;3421 if (diter->basename[0] == '.')3422 continue;3423 if (ends_with(diter->basename, ".lock"))3424 continue;34253426 if (read_ref_full(diter->relative_path, 0,3427 iter->oid.hash, &flags)) {3428 error("bad ref for %s", diter->path.buf);3429 continue;3430 }34313432 iter->base.refname = diter->relative_path;3433 iter->base.oid = &iter->oid;3434 iter->base.flags = flags;3435 return ITER_OK;3436 }34373438 iter->dir_iterator = NULL;3439 if (ref_iterator_abort(ref_iterator) == ITER_ERROR)3440 ok = ITER_ERROR;3441 return ok;3442}34433444static int files_reflog_iterator_peel(struct ref_iterator *ref_iterator,3445 struct object_id *peeled)3446{3447 die("BUG: ref_iterator_peel() called for reflog_iterator");3448}34493450static int files_reflog_iterator_abort(struct ref_iterator *ref_iterator)3451{3452 struct files_reflog_iterator *iter =3453 (struct files_reflog_iterator *)ref_iterator;3454 int ok = ITER_DONE;34553456 if (iter->dir_iterator)3457 ok = dir_iterator_abort(iter->dir_iterator);34583459 base_ref_iterator_free(ref_iterator);3460 return ok;3461}34623463static struct ref_iterator_vtable files_reflog_iterator_vtable = {3464 files_reflog_iterator_advance,3465 files_reflog_iterator_peel,3466 files_reflog_iterator_abort3467};34683469static struct ref_iterator *files_reflog_iterator_begin(struct ref_store *ref_store)3470{3471 struct files_ref_store *refs =3472 files_downcast(ref_store, REF_STORE_READ,3473 "reflog_iterator_begin");3474 struct files_reflog_iterator *iter = xcalloc(1, sizeof(*iter));3475 struct ref_iterator *ref_iterator = &iter->base;3476 struct strbuf sb = STRBUF_INIT;34773478 base_ref_iterator_init(ref_iterator, &files_reflog_iterator_vtable);3479 files_reflog_path(refs, &sb, NULL);3480 iter->dir_iterator = dir_iterator_begin(sb.buf);3481 strbuf_release(&sb);3482 return ref_iterator;3483}34843485static int ref_update_reject_duplicates(struct string_list *refnames,3486 struct strbuf *err)3487{3488 int i, n = refnames->nr;34893490 assert(err);34913492 for (i = 1; i < n; i++)3493 if (!strcmp(refnames->items[i - 1].string, refnames->items[i].string)) {3494 strbuf_addf(err,3495 "multiple updates for ref '%s' not allowed.",3496 refnames->items[i].string);3497 return 1;3498 }3499 return 0;3500}35013502/*3503 * If update is a direct update of head_ref (the reference pointed to3504 * by HEAD), then add an extra REF_LOG_ONLY update for HEAD.3505 */3506static int split_head_update(struct ref_update *update,3507 struct ref_transaction *transaction,3508 const char *head_ref,3509 struct string_list *affected_refnames,3510 struct strbuf *err)3511{3512 struct string_list_item *item;3513 struct ref_update *new_update;35143515 if ((update->flags & REF_LOG_ONLY) ||3516 (update->flags & REF_ISPRUNING) ||3517 (update->flags & REF_UPDATE_VIA_HEAD))3518 return 0;35193520 if (strcmp(update->refname, head_ref))3521 return 0;35223523 /*3524 * First make sure that HEAD is not already in the3525 * transaction. This insertion is O(N) in the transaction3526 * size, but it happens at most once per transaction.3527 */3528 item = string_list_insert(affected_refnames, "HEAD");3529 if (item->util) {3530 /* An entry already existed */3531 strbuf_addf(err,3532 "multiple updates for 'HEAD' (including one "3533 "via its referent '%s') are not allowed",3534 update->refname);3535 return TRANSACTION_NAME_CONFLICT;3536 }35373538 new_update = ref_transaction_add_update(3539 transaction, "HEAD",3540 update->flags | REF_LOG_ONLY | REF_NODEREF,3541 update->new_sha1, update->old_sha1,3542 update->msg);35433544 item->util = new_update;35453546 return 0;3547}35483549/*3550 * update is for a symref that points at referent and doesn't have3551 * REF_NODEREF set. Split it into two updates:3552 * - The original update, but with REF_LOG_ONLY and REF_NODEREF set3553 * - A new, separate update for the referent reference3554 * Note that the new update will itself be subject to splitting when3555 * the iteration gets to it.3556 */3557static int split_symref_update(struct files_ref_store *refs,3558 struct ref_update *update,3559 const char *referent,3560 struct ref_transaction *transaction,3561 struct string_list *affected_refnames,3562 struct strbuf *err)3563{3564 struct string_list_item *item;3565 struct ref_update *new_update;3566 unsigned int new_flags;35673568 /*3569 * First make sure that referent is not already in the3570 * transaction. This insertion is O(N) in the transaction3571 * size, but it happens at most once per symref in a3572 * transaction.3573 */3574 item = string_list_insert(affected_refnames, referent);3575 if (item->util) {3576 /* An entry already existed */3577 strbuf_addf(err,3578 "multiple updates for '%s' (including one "3579 "via symref '%s') are not allowed",3580 referent, update->refname);3581 return TRANSACTION_NAME_CONFLICT;3582 }35833584 new_flags = update->flags;3585 if (!strcmp(update->refname, "HEAD")) {3586 /*3587 * Record that the new update came via HEAD, so that3588 * when we process it, split_head_update() doesn't try3589 * to add another reflog update for HEAD. Note that3590 * this bit will be propagated if the new_update3591 * itself needs to be split.3592 */3593 new_flags |= REF_UPDATE_VIA_HEAD;3594 }35953596 new_update = ref_transaction_add_update(3597 transaction, referent, new_flags,3598 update->new_sha1, update->old_sha1,3599 update->msg);36003601 new_update->parent_update = update;36023603 /*3604 * Change the symbolic ref update to log only. Also, it3605 * doesn't need to check its old SHA-1 value, as that will be3606 * done when new_update is processed.3607 */3608 update->flags |= REF_LOG_ONLY | REF_NODEREF;3609 update->flags &= ~REF_HAVE_OLD;36103611 item->util = new_update;36123613 return 0;3614}36153616/*3617 * Return the refname under which update was originally requested.3618 */3619static const char *original_update_refname(struct ref_update *update)3620{3621 while (update->parent_update)3622 update = update->parent_update;36233624 return update->refname;3625}36263627/*3628 * Check whether the REF_HAVE_OLD and old_oid values stored in update3629 * are consistent with oid, which is the reference's current value. If3630 * everything is OK, return 0; otherwise, write an error message to3631 * err and return -1.3632 */3633static int check_old_oid(struct ref_update *update, struct object_id *oid,3634 struct strbuf *err)3635{3636 if (!(update->flags & REF_HAVE_OLD) ||3637 !hashcmp(oid->hash, update->old_sha1))3638 return 0;36393640 if (is_null_sha1(update->old_sha1))3641 strbuf_addf(err, "cannot lock ref '%s': "3642 "reference already exists",3643 original_update_refname(update));3644 else if (is_null_oid(oid))3645 strbuf_addf(err, "cannot lock ref '%s': "3646 "reference is missing but expected %s",3647 original_update_refname(update),3648 sha1_to_hex(update->old_sha1));3649 else3650 strbuf_addf(err, "cannot lock ref '%s': "3651 "is at %s but expected %s",3652 original_update_refname(update),3653 oid_to_hex(oid),3654 sha1_to_hex(update->old_sha1));36553656 return -1;3657}36583659/*3660 * Prepare for carrying out update:3661 * - Lock the reference referred to by update.3662 * - Read the reference under lock.3663 * - Check that its old SHA-1 value (if specified) is correct, and in3664 * any case record it in update->lock->old_oid for later use when3665 * writing the reflog.3666 * - If it is a symref update without REF_NODEREF, split it up into a3667 * REF_LOG_ONLY update of the symref and add a separate update for3668 * the referent to transaction.3669 * - If it is an update of head_ref, add a corresponding REF_LOG_ONLY3670 * update of HEAD.3671 */3672static int lock_ref_for_update(struct files_ref_store *refs,3673 struct ref_update *update,3674 struct ref_transaction *transaction,3675 const char *head_ref,3676 struct string_list *affected_refnames,3677 struct strbuf *err)3678{3679 struct strbuf referent = STRBUF_INIT;3680 int mustexist = (update->flags & REF_HAVE_OLD) &&3681 !is_null_sha1(update->old_sha1);3682 int ret;3683 struct ref_lock *lock;36843685 files_assert_main_repository(refs, "lock_ref_for_update");36863687 if ((update->flags & REF_HAVE_NEW) && is_null_sha1(update->new_sha1))3688 update->flags |= REF_DELETING;36893690 if (head_ref) {3691 ret = split_head_update(update, transaction, head_ref,3692 affected_refnames, err);3693 if (ret)3694 return ret;3695 }36963697 ret = lock_raw_ref(refs, update->refname, mustexist,3698 affected_refnames, NULL,3699 &lock, &referent,3700 &update->type, err);3701 if (ret) {3702 char *reason;37033704 reason = strbuf_detach(err, NULL);3705 strbuf_addf(err, "cannot lock ref '%s': %s",3706 original_update_refname(update), reason);3707 free(reason);3708 return ret;3709 }37103711 update->backend_data = lock;37123713 if (update->type & REF_ISSYMREF) {3714 if (update->flags & REF_NODEREF) {3715 /*3716 * We won't be reading the referent as part of3717 * the transaction, so we have to read it here3718 * to record and possibly check old_sha1:3719 */3720 if (read_ref_full(referent.buf, 0,3721 lock->old_oid.hash, NULL)) {3722 if (update->flags & REF_HAVE_OLD) {3723 strbuf_addf(err, "cannot lock ref '%s': "3724 "error reading reference",3725 original_update_refname(update));3726 return -1;3727 }3728 } else if (check_old_oid(update, &lock->old_oid, err)) {3729 return TRANSACTION_GENERIC_ERROR;3730 }3731 } else {3732 /*3733 * Create a new update for the reference this3734 * symref is pointing at. Also, we will record3735 * and verify old_sha1 for this update as part3736 * of processing the split-off update, so we3737 * don't have to do it here.3738 */3739 ret = split_symref_update(refs, update,3740 referent.buf, transaction,3741 affected_refnames, err);3742 if (ret)3743 return ret;3744 }3745 } else {3746 struct ref_update *parent_update;37473748 if (check_old_oid(update, &lock->old_oid, err))3749 return TRANSACTION_GENERIC_ERROR;37503751 /*3752 * If this update is happening indirectly because of a3753 * symref update, record the old SHA-1 in the parent3754 * update:3755 */3756 for (parent_update = update->parent_update;3757 parent_update;3758 parent_update = parent_update->parent_update) {3759 struct ref_lock *parent_lock = parent_update->backend_data;3760 oidcpy(&parent_lock->old_oid, &lock->old_oid);3761 }3762 }37633764 if ((update->flags & REF_HAVE_NEW) &&3765 !(update->flags & REF_DELETING) &&3766 !(update->flags & REF_LOG_ONLY)) {3767 if (!(update->type & REF_ISSYMREF) &&3768 !hashcmp(lock->old_oid.hash, update->new_sha1)) {3769 /*3770 * The reference already has the desired3771 * value, so we don't need to write it.3772 */3773 } else if (write_ref_to_lockfile(lock, update->new_sha1,3774 err)) {3775 char *write_err = strbuf_detach(err, NULL);37763777 /*3778 * The lock was freed upon failure of3779 * write_ref_to_lockfile():3780 */3781 update->backend_data = NULL;3782 strbuf_addf(err,3783 "cannot update ref '%s': %s",3784 update->refname, write_err);3785 free(write_err);3786 return TRANSACTION_GENERIC_ERROR;3787 } else {3788 update->flags |= REF_NEEDS_COMMIT;3789 }3790 }3791 if (!(update->flags & REF_NEEDS_COMMIT)) {3792 /*3793 * We didn't call write_ref_to_lockfile(), so3794 * the lockfile is still open. Close it to3795 * free up the file descriptor:3796 */3797 if (close_ref(lock)) {3798 strbuf_addf(err, "couldn't close '%s.lock'",3799 update->refname);3800 return TRANSACTION_GENERIC_ERROR;3801 }3802 }3803 return 0;3804}38053806static int files_transaction_commit(struct ref_store *ref_store,3807 struct ref_transaction *transaction,3808 struct strbuf *err)3809{3810 struct files_ref_store *refs =3811 files_downcast(ref_store, REF_STORE_WRITE,3812 "ref_transaction_commit");3813 int ret = 0, i;3814 struct string_list refs_to_delete = STRING_LIST_INIT_NODUP;3815 struct string_list_item *ref_to_delete;3816 struct string_list affected_refnames = STRING_LIST_INIT_NODUP;3817 char *head_ref = NULL;3818 int head_type;3819 struct object_id head_oid;3820 struct strbuf sb = STRBUF_INIT;38213822 assert(err);38233824 if (transaction->state != REF_TRANSACTION_OPEN)3825 die("BUG: commit called for transaction that is not open");38263827 if (!transaction->nr) {3828 transaction->state = REF_TRANSACTION_CLOSED;3829 return 0;3830 }38313832 /*3833 * Fail if a refname appears more than once in the3834 * transaction. (If we end up splitting up any updates using3835 * split_symref_update() or split_head_update(), those3836 * functions will check that the new updates don't have the3837 * same refname as any existing ones.)3838 */3839 for (i = 0; i < transaction->nr; i++) {3840 struct ref_update *update = transaction->updates[i];3841 struct string_list_item *item =3842 string_list_append(&affected_refnames, update->refname);38433844 /*3845 * We store a pointer to update in item->util, but at3846 * the moment we never use the value of this field3847 * except to check whether it is non-NULL.3848 */3849 item->util = update;3850 }3851 string_list_sort(&affected_refnames);3852 if (ref_update_reject_duplicates(&affected_refnames, err)) {3853 ret = TRANSACTION_GENERIC_ERROR;3854 goto cleanup;3855 }38563857 /*3858 * Special hack: If a branch is updated directly and HEAD3859 * points to it (may happen on the remote side of a push3860 * for example) then logically the HEAD reflog should be3861 * updated too.3862 *3863 * A generic solution would require reverse symref lookups,3864 * but finding all symrefs pointing to a given branch would be3865 * rather costly for this rare event (the direct update of a3866 * branch) to be worth it. So let's cheat and check with HEAD3867 * only, which should cover 99% of all usage scenarios (even3868 * 100% of the default ones).3869 *3870 * So if HEAD is a symbolic reference, then record the name of3871 * the reference that it points to. If we see an update of3872 * head_ref within the transaction, then split_head_update()3873 * arranges for the reflog of HEAD to be updated, too.3874 */3875 head_ref = resolve_refdup("HEAD", RESOLVE_REF_NO_RECURSE,3876 head_oid.hash, &head_type);38773878 if (head_ref && !(head_type & REF_ISSYMREF)) {3879 free(head_ref);3880 head_ref = NULL;3881 }38823883 /*3884 * Acquire all locks, verify old values if provided, check3885 * that new values are valid, and write new values to the3886 * lockfiles, ready to be activated. Only keep one lockfile3887 * open at a time to avoid running out of file descriptors.3888 */3889 for (i = 0; i < transaction->nr; i++) {3890 struct ref_update *update = transaction->updates[i];38913892 ret = lock_ref_for_update(refs, update, transaction,3893 head_ref, &affected_refnames, err);3894 if (ret)3895 goto cleanup;3896 }38973898 /* Perform updates first so live commits remain referenced */3899 for (i = 0; i < transaction->nr; i++) {3900 struct ref_update *update = transaction->updates[i];3901 struct ref_lock *lock = update->backend_data;39023903 if (update->flags & REF_NEEDS_COMMIT ||3904 update->flags & REF_LOG_ONLY) {3905 if (files_log_ref_write(refs,3906 lock->ref_name,3907 lock->old_oid.hash,3908 update->new_sha1,3909 update->msg, update->flags,3910 err)) {3911 char *old_msg = strbuf_detach(err, NULL);39123913 strbuf_addf(err, "cannot update the ref '%s': %s",3914 lock->ref_name, old_msg);3915 free(old_msg);3916 unlock_ref(lock);3917 update->backend_data = NULL;3918 ret = TRANSACTION_GENERIC_ERROR;3919 goto cleanup;3920 }3921 }3922 if (update->flags & REF_NEEDS_COMMIT) {3923 clear_loose_ref_cache(refs);3924 if (commit_ref(lock)) {3925 strbuf_addf(err, "couldn't set '%s'", lock->ref_name);3926 unlock_ref(lock);3927 update->backend_data = NULL;3928 ret = TRANSACTION_GENERIC_ERROR;3929 goto cleanup;3930 }3931 }3932 }3933 /* Perform deletes now that updates are safely completed */3934 for (i = 0; i < transaction->nr; i++) {3935 struct ref_update *update = transaction->updates[i];3936 struct ref_lock *lock = update->backend_data;39373938 if (update->flags & REF_DELETING &&3939 !(update->flags & REF_LOG_ONLY)) {3940 if (!(update->type & REF_ISPACKED) ||3941 update->type & REF_ISSYMREF) {3942 /* It is a loose reference. */3943 strbuf_reset(&sb);3944 files_ref_path(refs, &sb, lock->ref_name);3945 if (unlink_or_msg(sb.buf, err)) {3946 ret = TRANSACTION_GENERIC_ERROR;3947 goto cleanup;3948 }3949 update->flags |= REF_DELETED_LOOSE;3950 }39513952 if (!(update->flags & REF_ISPRUNING))3953 string_list_append(&refs_to_delete,3954 lock->ref_name);3955 }3956 }39573958 if (repack_without_refs(refs, &refs_to_delete, err)) {3959 ret = TRANSACTION_GENERIC_ERROR;3960 goto cleanup;3961 }39623963 /* Delete the reflogs of any references that were deleted: */3964 for_each_string_list_item(ref_to_delete, &refs_to_delete) {3965 strbuf_reset(&sb);3966 files_reflog_path(refs, &sb, ref_to_delete->string);3967 if (!unlink_or_warn(sb.buf))3968 try_remove_empty_parents(refs, ref_to_delete->string,3969 REMOVE_EMPTY_PARENTS_REFLOG);3970 }39713972 clear_loose_ref_cache(refs);39733974cleanup:3975 strbuf_release(&sb);3976 transaction->state = REF_TRANSACTION_CLOSED;39773978 for (i = 0; i < transaction->nr; i++) {3979 struct ref_update *update = transaction->updates[i];3980 struct ref_lock *lock = update->backend_data;39813982 if (lock)3983 unlock_ref(lock);39843985 if (update->flags & REF_DELETED_LOOSE) {3986 /*3987 * The loose reference was deleted. Delete any3988 * empty parent directories. (Note that this3989 * can only work because we have already3990 * removed the lockfile.)3991 */3992 try_remove_empty_parents(refs, update->refname,3993 REMOVE_EMPTY_PARENTS_REF);3994 }3995 }39963997 string_list_clear(&refs_to_delete, 0);3998 free(head_ref);3999 string_list_clear(&affected_refnames, 0);40004001 return ret;4002}40034004static int ref_present(const char *refname,4005 const struct object_id *oid, int flags, void *cb_data)4006{4007 struct string_list *affected_refnames = cb_data;40084009 return string_list_has_string(affected_refnames, refname);4010}40114012static int files_initial_transaction_commit(struct ref_store *ref_store,4013 struct ref_transaction *transaction,4014 struct strbuf *err)4015{4016 struct files_ref_store *refs =4017 files_downcast(ref_store, REF_STORE_WRITE,4018 "initial_ref_transaction_commit");4019 int ret = 0, i;4020 struct string_list affected_refnames = STRING_LIST_INIT_NODUP;40214022 assert(err);40234024 if (transaction->state != REF_TRANSACTION_OPEN)4025 die("BUG: commit called for transaction that is not open");40264027 /* Fail if a refname appears more than once in the transaction: */4028 for (i = 0; i < transaction->nr; i++)4029 string_list_append(&affected_refnames,4030 transaction->updates[i]->refname);4031 string_list_sort(&affected_refnames);4032 if (ref_update_reject_duplicates(&affected_refnames, err)) {4033 ret = TRANSACTION_GENERIC_ERROR;4034 goto cleanup;4035 }40364037 /*4038 * It's really undefined to call this function in an active4039 * repository or when there are existing references: we are4040 * only locking and changing packed-refs, so (1) any4041 * simultaneous processes might try to change a reference at4042 * the same time we do, and (2) any existing loose versions of4043 * the references that we are setting would have precedence4044 * over our values. But some remote helpers create the remote4045 * "HEAD" and "master" branches before calling this function,4046 * so here we really only check that none of the references4047 * that we are creating already exists.4048 */4049 if (for_each_rawref(ref_present, &affected_refnames))4050 die("BUG: initial ref transaction called with existing refs");40514052 for (i = 0; i < transaction->nr; i++) {4053 struct ref_update *update = transaction->updates[i];40544055 if ((update->flags & REF_HAVE_OLD) &&4056 !is_null_sha1(update->old_sha1))4057 die("BUG: initial ref transaction with old_sha1 set");4058 if (refs_verify_refname_available(&refs->base, update->refname,4059 &affected_refnames, NULL,4060 err)) {4061 ret = TRANSACTION_NAME_CONFLICT;4062 goto cleanup;4063 }4064 }40654066 if (lock_packed_refs(refs, 0)) {4067 strbuf_addf(err, "unable to lock packed-refs file: %s",4068 strerror(errno));4069 ret = TRANSACTION_GENERIC_ERROR;4070 goto cleanup;4071 }40724073 for (i = 0; i < transaction->nr; i++) {4074 struct ref_update *update = transaction->updates[i];40754076 if ((update->flags & REF_HAVE_NEW) &&4077 !is_null_sha1(update->new_sha1))4078 add_packed_ref(refs, update->refname, update->new_sha1);4079 }40804081 if (commit_packed_refs(refs)) {4082 strbuf_addf(err, "unable to commit packed-refs file: %s",4083 strerror(errno));4084 ret = TRANSACTION_GENERIC_ERROR;4085 goto cleanup;4086 }40874088cleanup:4089 transaction->state = REF_TRANSACTION_CLOSED;4090 string_list_clear(&affected_refnames, 0);4091 return ret;4092}40934094struct expire_reflog_cb {4095 unsigned int flags;4096 reflog_expiry_should_prune_fn *should_prune_fn;4097 void *policy_cb;4098 FILE *newlog;4099 struct object_id last_kept_oid;4100};41014102static int expire_reflog_ent(struct object_id *ooid, struct object_id *noid,4103 const char *email, unsigned long timestamp, int tz,4104 const char *message, void *cb_data)4105{4106 struct expire_reflog_cb *cb = cb_data;4107 struct expire_reflog_policy_cb *policy_cb = cb->policy_cb;41084109 if (cb->flags & EXPIRE_REFLOGS_REWRITE)4110 ooid = &cb->last_kept_oid;41114112 if ((*cb->should_prune_fn)(ooid->hash, noid->hash, email, timestamp, tz,4113 message, policy_cb)) {4114 if (!cb->newlog)4115 printf("would prune %s", message);4116 else if (cb->flags & EXPIRE_REFLOGS_VERBOSE)4117 printf("prune %s", message);4118 } else {4119 if (cb->newlog) {4120 fprintf(cb->newlog, "%s %s %s %lu %+05d\t%s",4121 oid_to_hex(ooid), oid_to_hex(noid),4122 email, timestamp, tz, message);4123 oidcpy(&cb->last_kept_oid, noid);4124 }4125 if (cb->flags & EXPIRE_REFLOGS_VERBOSE)4126 printf("keep %s", message);4127 }4128 return 0;4129}41304131static int files_reflog_expire(struct ref_store *ref_store,4132 const char *refname, const unsigned char *sha1,4133 unsigned int flags,4134 reflog_expiry_prepare_fn prepare_fn,4135 reflog_expiry_should_prune_fn should_prune_fn,4136 reflog_expiry_cleanup_fn cleanup_fn,4137 void *policy_cb_data)4138{4139 struct files_ref_store *refs =4140 files_downcast(ref_store, REF_STORE_WRITE, "reflog_expire");4141 static struct lock_file reflog_lock;4142 struct expire_reflog_cb cb;4143 struct ref_lock *lock;4144 struct strbuf log_file_sb = STRBUF_INIT;4145 char *log_file;4146 int status = 0;4147 int type;4148 struct strbuf err = STRBUF_INIT;41494150 memset(&cb, 0, sizeof(cb));4151 cb.flags = flags;4152 cb.policy_cb = policy_cb_data;4153 cb.should_prune_fn = should_prune_fn;41544155 /*4156 * The reflog file is locked by holding the lock on the4157 * reference itself, plus we might need to update the4158 * reference if --updateref was specified:4159 */4160 lock = lock_ref_sha1_basic(refs, refname, sha1,4161 NULL, NULL, REF_NODEREF,4162 &type, &err);4163 if (!lock) {4164 error("cannot lock ref '%s': %s", refname, err.buf);4165 strbuf_release(&err);4166 return -1;4167 }4168 if (!reflog_exists(refname)) {4169 unlock_ref(lock);4170 return 0;4171 }41724173 files_reflog_path(refs, &log_file_sb, refname);4174 log_file = strbuf_detach(&log_file_sb, NULL);4175 if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {4176 /*4177 * Even though holding $GIT_DIR/logs/$reflog.lock has4178 * no locking implications, we use the lock_file4179 * machinery here anyway because it does a lot of the4180 * work we need, including cleaning up if the program4181 * exits unexpectedly.4182 */4183 if (hold_lock_file_for_update(&reflog_lock, log_file, 0) < 0) {4184 struct strbuf err = STRBUF_INIT;4185 unable_to_lock_message(log_file, errno, &err);4186 error("%s", err.buf);4187 strbuf_release(&err);4188 goto failure;4189 }4190 cb.newlog = fdopen_lock_file(&reflog_lock, "w");4191 if (!cb.newlog) {4192 error("cannot fdopen %s (%s)",4193 get_lock_file_path(&reflog_lock), strerror(errno));4194 goto failure;4195 }4196 }41974198 (*prepare_fn)(refname, sha1, cb.policy_cb);4199 for_each_reflog_ent(refname, expire_reflog_ent, &cb);4200 (*cleanup_fn)(cb.policy_cb);42014202 if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {4203 /*4204 * It doesn't make sense to adjust a reference pointed4205 * to by a symbolic ref based on expiring entries in4206 * the symbolic reference's reflog. Nor can we update4207 * a reference if there are no remaining reflog4208 * entries.4209 */4210 int update = (flags & EXPIRE_REFLOGS_UPDATE_REF) &&4211 !(type & REF_ISSYMREF) &&4212 !is_null_oid(&cb.last_kept_oid);42134214 if (close_lock_file(&reflog_lock)) {4215 status |= error("couldn't write %s: %s", log_file,4216 strerror(errno));4217 } else if (update &&4218 (write_in_full(get_lock_file_fd(lock->lk),4219 oid_to_hex(&cb.last_kept_oid), GIT_SHA1_HEXSZ) != GIT_SHA1_HEXSZ ||4220 write_str_in_full(get_lock_file_fd(lock->lk), "\n") != 1 ||4221 close_ref(lock) < 0)) {4222 status |= error("couldn't write %s",4223 get_lock_file_path(lock->lk));4224 rollback_lock_file(&reflog_lock);4225 } else if (commit_lock_file(&reflog_lock)) {4226 status |= error("unable to write reflog '%s' (%s)",4227 log_file, strerror(errno));4228 } else if (update && commit_ref(lock)) {4229 status |= error("couldn't set %s", lock->ref_name);4230 }4231 }4232 free(log_file);4233 unlock_ref(lock);4234 return status;42354236 failure:4237 rollback_lock_file(&reflog_lock);4238 free(log_file);4239 unlock_ref(lock);4240 return -1;4241}42424243static int files_init_db(struct ref_store *ref_store, struct strbuf *err)4244{4245 struct files_ref_store *refs =4246 files_downcast(ref_store, REF_STORE_WRITE, "init_db");4247 struct strbuf sb = STRBUF_INIT;42484249 /*4250 * Create .git/refs/{heads,tags}4251 */4252 files_ref_path(refs, &sb, "refs/heads");4253 safe_create_dir(sb.buf, 1);42544255 strbuf_reset(&sb);4256 files_ref_path(refs, &sb, "refs/tags");4257 safe_create_dir(sb.buf, 1);42584259 strbuf_release(&sb);4260 return 0;4261}42624263struct ref_storage_be refs_be_files = {4264 NULL,4265 "files",4266 files_ref_store_create,4267 files_init_db,4268 files_transaction_commit,4269 files_initial_transaction_commit,42704271 files_pack_refs,4272 files_peel_ref,4273 files_create_symref,4274 files_delete_refs,4275 files_rename_ref,42764277 files_ref_iterator_begin,4278 files_read_raw_ref,4279 files_verify_refname_available,42804281 files_reflog_iterator_begin,4282 files_for_each_reflog_ent,4283 files_for_each_reflog_ent_reverse,4284 files_reflog_exists,4285 files_create_reflog,4286 files_delete_reflog,4287 files_reflog_expire4288};