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); 168 169static struct ref_dir *get_ref_dir(struct ref_entry *entry) 170{ 171 struct ref_dir *dir; 172 assert(entry->flag & REF_DIR); 173 dir = &entry->u.subdir; 174 if (entry->flag & REF_INCOMPLETE) { 175 read_loose_refs(entry->name, dir); 176 177 /* 178 * Manually add refs/bisect, which, being 179 * per-worktree, might not appear in the directory 180 * listing for refs/ in the main repo. 181 */ 182 if (!strcmp(entry->name, "refs/")) { 183 int pos = search_ref_dir(dir, "refs/bisect/", 12); 184 if (pos < 0) { 185 struct ref_entry *child_entry; 186 child_entry = create_dir_entry(dir->ref_store, 187 "refs/bisect/", 188 12, 1); 189 add_entry_to_dir(dir, child_entry); 190 read_loose_refs("refs/bisect", 191 &child_entry->u.subdir); 192 } 193 } 194 entry->flag &= ~REF_INCOMPLETE; 195 } 196 return dir; 197} 198 199static struct ref_entry *create_ref_entry(const char *refname, 200 const unsigned char *sha1, int flag, 201 int check_name) 202{ 203 struct ref_entry *ref; 204 205 if (check_name && 206 check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) 207 die("Reference has invalid format: '%s'", refname); 208 FLEX_ALLOC_STR(ref, name, refname); 209 hashcpy(ref->u.value.oid.hash, sha1); 210 oidclr(&ref->u.value.peeled); 211 ref->flag = flag; 212 return ref; 213} 214 215static void clear_ref_dir(struct ref_dir *dir); 216 217static void free_ref_entry(struct ref_entry *entry) 218{ 219 if (entry->flag & REF_DIR) { 220 /* 221 * Do not use get_ref_dir() here, as that might 222 * trigger the reading of loose refs. 223 */ 224 clear_ref_dir(&entry->u.subdir); 225 } 226 free(entry); 227} 228 229/* 230 * Add a ref_entry to the end of dir (unsorted). Entry is always 231 * stored directly in dir; no recursion into subdirectories is 232 * done. 233 */ 234static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry) 235{ 236 ALLOC_GROW(dir->entries, dir->nr + 1, dir->alloc); 237 dir->entries[dir->nr++] = entry; 238 /* optimize for the case that entries are added in order */ 239 if (dir->nr == 1 || 240 (dir->nr == dir->sorted + 1 && 241 strcmp(dir->entries[dir->nr - 2]->name, 242 dir->entries[dir->nr - 1]->name) < 0)) 243 dir->sorted = dir->nr; 244} 245 246/* 247 * Clear and free all entries in dir, recursively. 248 */ 249static void clear_ref_dir(struct ref_dir *dir) 250{ 251 int i; 252 for (i = 0; i < dir->nr; i++) 253 free_ref_entry(dir->entries[i]); 254 free(dir->entries); 255 dir->sorted = dir->nr = dir->alloc = 0; 256 dir->entries = NULL; 257} 258 259/* 260 * Create a struct ref_entry object for the specified dirname. 261 * dirname is the name of the directory with a trailing slash (e.g., 262 * "refs/heads/") or "" for the top-level directory. 263 */ 264static struct ref_entry *create_dir_entry(struct files_ref_store *ref_store, 265 const char *dirname, size_t len, 266 int incomplete) 267{ 268 struct ref_entry *direntry; 269 FLEX_ALLOC_MEM(direntry, name, dirname, len); 270 direntry->u.subdir.ref_store = ref_store; 271 direntry->flag = REF_DIR | (incomplete ? REF_INCOMPLETE : 0); 272 return direntry; 273} 274 275static int ref_entry_cmp(const void *a, const void *b) 276{ 277 struct ref_entry *one = *(struct ref_entry **)a; 278 struct ref_entry *two = *(struct ref_entry **)b; 279 return strcmp(one->name, two->name); 280} 281 282static void sort_ref_dir(struct ref_dir *dir); 283 284struct string_slice { 285 size_t len; 286 const char *str; 287}; 288 289static int ref_entry_cmp_sslice(const void *key_, const void *ent_) 290{ 291 const struct string_slice *key = key_; 292 const struct ref_entry *ent = *(const struct ref_entry * const *)ent_; 293 int cmp = strncmp(key->str, ent->name, key->len); 294 if (cmp) 295 return cmp; 296 return '\0' - (unsigned char)ent->name[key->len]; 297} 298 299/* 300 * Return the index of the entry with the given refname from the 301 * ref_dir (non-recursively), sorting dir if necessary. Return -1 if 302 * no such entry is found. dir must already be complete. 303 */ 304static int search_ref_dir(struct ref_dir *dir, const char *refname, size_t len) 305{ 306 struct ref_entry **r; 307 struct string_slice key; 308 309 if (refname == NULL || !dir->nr) 310 return -1; 311 312 sort_ref_dir(dir); 313 key.len = len; 314 key.str = refname; 315 r = bsearch(&key, dir->entries, dir->nr, sizeof(*dir->entries), 316 ref_entry_cmp_sslice); 317 318 if (r == NULL) 319 return -1; 320 321 return r - dir->entries; 322} 323 324/* 325 * Search for a directory entry directly within dir (without 326 * recursing). Sort dir if necessary. subdirname must be a directory 327 * name (i.e., end in '/'). If mkdir is set, then create the 328 * directory if it is missing; otherwise, return NULL if the desired 329 * directory cannot be found. dir must already be complete. 330 */ 331static struct ref_dir *search_for_subdir(struct ref_dir *dir, 332 const char *subdirname, size_t len, 333 int mkdir) 334{ 335 int entry_index = search_ref_dir(dir, subdirname, len); 336 struct ref_entry *entry; 337 if (entry_index == -1) { 338 if (!mkdir) 339 return NULL; 340 /* 341 * Since dir is complete, the absence of a subdir 342 * means that the subdir really doesn't exist; 343 * therefore, create an empty record for it but mark 344 * the record complete. 345 */ 346 entry = create_dir_entry(dir->ref_store, subdirname, len, 0); 347 add_entry_to_dir(dir, entry); 348 } else { 349 entry = dir->entries[entry_index]; 350 } 351 return get_ref_dir(entry); 352} 353 354/* 355 * If refname is a reference name, find the ref_dir within the dir 356 * tree that should hold refname. If refname is a directory name 357 * (i.e., ends in '/'), then return that ref_dir itself. dir must 358 * represent the top-level directory and must already be complete. 359 * Sort ref_dirs and recurse into subdirectories as necessary. If 360 * mkdir is set, then create any missing directories; otherwise, 361 * return NULL if the desired directory cannot be found. 362 */ 363static struct ref_dir *find_containing_dir(struct ref_dir *dir, 364 const char *refname, int mkdir) 365{ 366 const char *slash; 367 for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) { 368 size_t dirnamelen = slash - refname + 1; 369 struct ref_dir *subdir; 370 subdir = search_for_subdir(dir, refname, dirnamelen, mkdir); 371 if (!subdir) { 372 dir = NULL; 373 break; 374 } 375 dir = subdir; 376 } 377 378 return dir; 379} 380 381/* 382 * Find the value entry with the given name in dir, sorting ref_dirs 383 * and recursing into subdirectories as necessary. If the name is not 384 * found or it corresponds to a directory entry, return NULL. 385 */ 386static struct ref_entry *find_ref(struct ref_dir *dir, const char *refname) 387{ 388 int entry_index; 389 struct ref_entry *entry; 390 dir = find_containing_dir(dir, refname, 0); 391 if (!dir) 392 return NULL; 393 entry_index = search_ref_dir(dir, refname, strlen(refname)); 394 if (entry_index == -1) 395 return NULL; 396 entry = dir->entries[entry_index]; 397 return (entry->flag & REF_DIR) ? NULL : entry; 398} 399 400/* 401 * Remove the entry with the given name from dir, recursing into 402 * subdirectories as necessary. If refname is the name of a directory 403 * (i.e., ends with '/'), then remove the directory and its contents. 404 * If the removal was successful, return the number of entries 405 * remaining in the directory entry that contained the deleted entry. 406 * If the name was not found, return -1. Please note that this 407 * function only deletes the entry from the cache; it does not delete 408 * it from the filesystem or ensure that other cache entries (which 409 * might be symbolic references to the removed entry) are updated. 410 * Nor does it remove any containing dir entries that might be made 411 * empty by the removal. dir must represent the top-level directory 412 * and must already be complete. 413 */ 414static int remove_entry(struct ref_dir *dir, const char *refname) 415{ 416 int refname_len = strlen(refname); 417 int entry_index; 418 struct ref_entry *entry; 419 int is_dir = refname[refname_len - 1] == '/'; 420 if (is_dir) { 421 /* 422 * refname represents a reference directory. Remove 423 * the trailing slash; otherwise we will get the 424 * directory *representing* refname rather than the 425 * one *containing* it. 426 */ 427 char *dirname = xmemdupz(refname, refname_len - 1); 428 dir = find_containing_dir(dir, dirname, 0); 429 free(dirname); 430 } else { 431 dir = find_containing_dir(dir, refname, 0); 432 } 433 if (!dir) 434 return -1; 435 entry_index = search_ref_dir(dir, refname, refname_len); 436 if (entry_index == -1) 437 return -1; 438 entry = dir->entries[entry_index]; 439 440 memmove(&dir->entries[entry_index], 441 &dir->entries[entry_index + 1], 442 (dir->nr - entry_index - 1) * sizeof(*dir->entries) 443 ); 444 dir->nr--; 445 if (dir->sorted > entry_index) 446 dir->sorted--; 447 free_ref_entry(entry); 448 return dir->nr; 449} 450 451/* 452 * Add a ref_entry to the ref_dir (unsorted), recursing into 453 * subdirectories as necessary. dir must represent the top-level 454 * directory. Return 0 on success. 455 */ 456static int add_ref(struct ref_dir *dir, struct ref_entry *ref) 457{ 458 dir = find_containing_dir(dir, ref->name, 1); 459 if (!dir) 460 return -1; 461 add_entry_to_dir(dir, ref); 462 return 0; 463} 464 465/* 466 * Emit a warning and return true iff ref1 and ref2 have the same name 467 * and the same sha1. Die if they have the same name but different 468 * sha1s. 469 */ 470static int is_dup_ref(const struct ref_entry *ref1, const struct ref_entry *ref2) 471{ 472 if (strcmp(ref1->name, ref2->name)) 473 return 0; 474 475 /* Duplicate name; make sure that they don't conflict: */ 476 477 if ((ref1->flag & REF_DIR) || (ref2->flag & REF_DIR)) 478 /* This is impossible by construction */ 479 die("Reference directory conflict: %s", ref1->name); 480 481 if (oidcmp(&ref1->u.value.oid, &ref2->u.value.oid)) 482 die("Duplicated ref, and SHA1s don't match: %s", ref1->name); 483 484 warning("Duplicated ref: %s", ref1->name); 485 return 1; 486} 487 488/* 489 * Sort the entries in dir non-recursively (if they are not already 490 * sorted) and remove any duplicate entries. 491 */ 492static void sort_ref_dir(struct ref_dir *dir) 493{ 494 int i, j; 495 struct ref_entry *last = NULL; 496 497 /* 498 * This check also prevents passing a zero-length array to qsort(), 499 * which is a problem on some platforms. 500 */ 501 if (dir->sorted == dir->nr) 502 return; 503 504 qsort(dir->entries, dir->nr, sizeof(*dir->entries), ref_entry_cmp); 505 506 /* Remove any duplicates: */ 507 for (i = 0, j = 0; j < dir->nr; j++) { 508 struct ref_entry *entry = dir->entries[j]; 509 if (last && is_dup_ref(last, entry)) 510 free_ref_entry(entry); 511 else 512 last = dir->entries[i++] = entry; 513 } 514 dir->sorted = dir->nr = i; 515} 516 517/* 518 * Return true if refname, which has the specified oid and flags, can 519 * be resolved to an object in the database. If the referred-to object 520 * does not exist, emit a warning and return false. 521 */ 522static int ref_resolves_to_object(const char *refname, 523 const struct object_id *oid, 524 unsigned int flags) 525{ 526 if (flags & REF_ISBROKEN) 527 return 0; 528 if (!has_sha1_file(oid->hash)) { 529 error("%s does not point to a valid object!", refname); 530 return 0; 531 } 532 return 1; 533} 534 535/* 536 * Return true if the reference described by entry can be resolved to 537 * an object in the database; otherwise, emit a warning and return 538 * false. 539 */ 540static int entry_resolves_to_object(struct ref_entry *entry) 541{ 542 return ref_resolves_to_object(entry->name, 543 &entry->u.value.oid, entry->flag); 544} 545 546typedef int each_ref_entry_fn(struct ref_entry *entry, void *cb_data); 547 548/* 549 * Call fn for each reference in dir that has index in the range 550 * offset <= index < dir->nr. Recurse into subdirectories that are in 551 * that index range, sorting them before iterating. This function 552 * does not sort dir itself; it should be sorted beforehand. fn is 553 * called for all references, including broken ones. 554 */ 555static int do_for_each_entry_in_dir(struct ref_dir *dir, int offset, 556 each_ref_entry_fn fn, void *cb_data) 557{ 558 int i; 559 assert(dir->sorted == dir->nr); 560 for (i = offset; i < dir->nr; i++) { 561 struct ref_entry *entry = dir->entries[i]; 562 int retval; 563 if (entry->flag & REF_DIR) { 564 struct ref_dir *subdir = get_ref_dir(entry); 565 sort_ref_dir(subdir); 566 retval = do_for_each_entry_in_dir(subdir, 0, fn, cb_data); 567 } else { 568 retval = fn(entry, cb_data); 569 } 570 if (retval) 571 return retval; 572 } 573 return 0; 574} 575 576/* 577 * Load all of the refs from the dir into our in-memory cache. The hard work 578 * of loading loose refs is done by get_ref_dir(), so we just need to recurse 579 * through all of the sub-directories. We do not even need to care about 580 * sorting, as traversal order does not matter to us. 581 */ 582static void prime_ref_dir(struct ref_dir *dir) 583{ 584 int i; 585 for (i = 0; i < dir->nr; i++) { 586 struct ref_entry *entry = dir->entries[i]; 587 if (entry->flag & REF_DIR) 588 prime_ref_dir(get_ref_dir(entry)); 589 } 590} 591 592/* 593 * A level in the reference hierarchy that is currently being iterated 594 * through. 595 */ 596struct cache_ref_iterator_level { 597 /* 598 * The ref_dir being iterated over at this level. The ref_dir 599 * is sorted before being stored here. 600 */ 601 struct ref_dir *dir; 602 603 /* 604 * The index of the current entry within dir (which might 605 * itself be a directory). If index == -1, then the iteration 606 * hasn't yet begun. If index == dir->nr, then the iteration 607 * through this level is over. 608 */ 609 int index; 610}; 611 612/* 613 * Represent an iteration through a ref_dir in the memory cache. The 614 * iteration recurses through subdirectories. 615 */ 616struct cache_ref_iterator { 617 struct ref_iterator base; 618 619 /* 620 * The number of levels currently on the stack. This is always 621 * at least 1, because when it becomes zero the iteration is 622 * ended and this struct is freed. 623 */ 624 size_t levels_nr; 625 626 /* The number of levels that have been allocated on the stack */ 627 size_t levels_alloc; 628 629 /* 630 * A stack of levels. levels[0] is the uppermost level that is 631 * being iterated over in this iteration. (This is not 632 * necessary the top level in the references hierarchy. If we 633 * are iterating through a subtree, then levels[0] will hold 634 * the ref_dir for that subtree, and subsequent levels will go 635 * on from there.) 636 */ 637 struct cache_ref_iterator_level *levels; 638}; 639 640static int cache_ref_iterator_advance(struct ref_iterator *ref_iterator) 641{ 642 struct cache_ref_iterator *iter = 643 (struct cache_ref_iterator *)ref_iterator; 644 645 while (1) { 646 struct cache_ref_iterator_level *level = 647 &iter->levels[iter->levels_nr - 1]; 648 struct ref_dir *dir = level->dir; 649 struct ref_entry *entry; 650 651 if (level->index == -1) 652 sort_ref_dir(dir); 653 654 if (++level->index == level->dir->nr) { 655 /* This level is exhausted; pop up a level */ 656 if (--iter->levels_nr == 0) 657 return ref_iterator_abort(ref_iterator); 658 659 continue; 660 } 661 662 entry = dir->entries[level->index]; 663 664 if (entry->flag & REF_DIR) { 665 /* push down a level */ 666 ALLOC_GROW(iter->levels, iter->levels_nr + 1, 667 iter->levels_alloc); 668 669 level = &iter->levels[iter->levels_nr++]; 670 level->dir = get_ref_dir(entry); 671 level->index = -1; 672 } else { 673 iter->base.refname = entry->name; 674 iter->base.oid = &entry->u.value.oid; 675 iter->base.flags = entry->flag; 676 return ITER_OK; 677 } 678 } 679} 680 681static enum peel_status peel_entry(struct ref_entry *entry, int repeel); 682 683static int cache_ref_iterator_peel(struct ref_iterator *ref_iterator, 684 struct object_id *peeled) 685{ 686 struct cache_ref_iterator *iter = 687 (struct cache_ref_iterator *)ref_iterator; 688 struct cache_ref_iterator_level *level; 689 struct ref_entry *entry; 690 691 level = &iter->levels[iter->levels_nr - 1]; 692 693 if (level->index == -1) 694 die("BUG: peel called before advance for cache iterator"); 695 696 entry = level->dir->entries[level->index]; 697 698 if (peel_entry(entry, 0)) 699 return -1; 700 hashcpy(peeled->hash, entry->u.value.peeled.hash); 701 return 0; 702} 703 704static int cache_ref_iterator_abort(struct ref_iterator *ref_iterator) 705{ 706 struct cache_ref_iterator *iter = 707 (struct cache_ref_iterator *)ref_iterator; 708 709 free(iter->levels); 710 base_ref_iterator_free(ref_iterator); 711 return ITER_DONE; 712} 713 714static struct ref_iterator_vtable cache_ref_iterator_vtable = { 715 cache_ref_iterator_advance, 716 cache_ref_iterator_peel, 717 cache_ref_iterator_abort 718}; 719 720static struct ref_iterator *cache_ref_iterator_begin(struct ref_dir *dir) 721{ 722 struct cache_ref_iterator *iter; 723 struct ref_iterator *ref_iterator; 724 struct cache_ref_iterator_level *level; 725 726 iter = xcalloc(1, sizeof(*iter)); 727 ref_iterator = &iter->base; 728 base_ref_iterator_init(ref_iterator, &cache_ref_iterator_vtable); 729 ALLOC_GROW(iter->levels, 10, iter->levels_alloc); 730 731 iter->levels_nr = 1; 732 level = &iter->levels[0]; 733 level->index = -1; 734 level->dir = dir; 735 736 return ref_iterator; 737} 738 739struct nonmatching_ref_data { 740 const struct string_list *skip; 741 const char *conflicting_refname; 742}; 743 744static int nonmatching_ref_fn(struct ref_entry *entry, void *vdata) 745{ 746 struct nonmatching_ref_data *data = vdata; 747 748 if (data->skip && string_list_has_string(data->skip, entry->name)) 749 return 0; 750 751 data->conflicting_refname = entry->name; 752 return 1; 753} 754 755/* 756 * Return 0 if a reference named refname could be created without 757 * conflicting with the name of an existing reference in dir. 758 * See verify_refname_available for more information. 759 */ 760static int verify_refname_available_dir(const char *refname, 761 const struct string_list *extras, 762 const struct string_list *skip, 763 struct ref_dir *dir, 764 struct strbuf *err) 765{ 766 const char *slash; 767 const char *extra_refname; 768 int pos; 769 struct strbuf dirname = STRBUF_INIT; 770 int ret = -1; 771 772 /* 773 * For the sake of comments in this function, suppose that 774 * refname is "refs/foo/bar". 775 */ 776 777 assert(err); 778 779 strbuf_grow(&dirname, strlen(refname) + 1); 780 for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) { 781 /* Expand dirname to the new prefix, not including the trailing slash: */ 782 strbuf_add(&dirname, refname + dirname.len, slash - refname - dirname.len); 783 784 /* 785 * We are still at a leading dir of the refname (e.g., 786 * "refs/foo"; if there is a reference with that name, 787 * it is a conflict, *unless* it is in skip. 788 */ 789 if (dir) { 790 pos = search_ref_dir(dir, dirname.buf, dirname.len); 791 if (pos >= 0 && 792 (!skip || !string_list_has_string(skip, dirname.buf))) { 793 /* 794 * We found a reference whose name is 795 * a proper prefix of refname; e.g., 796 * "refs/foo", and is not in skip. 797 */ 798 strbuf_addf(err, "'%s' exists; cannot create '%s'", 799 dirname.buf, refname); 800 goto cleanup; 801 } 802 } 803 804 if (extras && string_list_has_string(extras, dirname.buf) && 805 (!skip || !string_list_has_string(skip, dirname.buf))) { 806 strbuf_addf(err, "cannot process '%s' and '%s' at the same time", 807 refname, dirname.buf); 808 goto cleanup; 809 } 810 811 /* 812 * Otherwise, we can try to continue our search with 813 * the next component. So try to look up the 814 * directory, e.g., "refs/foo/". If we come up empty, 815 * we know there is nothing under this whole prefix, 816 * but even in that case we still have to continue the 817 * search for conflicts with extras. 818 */ 819 strbuf_addch(&dirname, '/'); 820 if (dir) { 821 pos = search_ref_dir(dir, dirname.buf, dirname.len); 822 if (pos < 0) { 823 /* 824 * There was no directory "refs/foo/", 825 * so there is nothing under this 826 * whole prefix. So there is no need 827 * to continue looking for conflicting 828 * references. But we need to continue 829 * looking for conflicting extras. 830 */ 831 dir = NULL; 832 } else { 833 dir = get_ref_dir(dir->entries[pos]); 834 } 835 } 836 } 837 838 /* 839 * We are at the leaf of our refname (e.g., "refs/foo/bar"). 840 * There is no point in searching for a reference with that 841 * name, because a refname isn't considered to conflict with 842 * itself. But we still need to check for references whose 843 * names are in the "refs/foo/bar/" namespace, because they 844 * *do* conflict. 845 */ 846 strbuf_addstr(&dirname, refname + dirname.len); 847 strbuf_addch(&dirname, '/'); 848 849 if (dir) { 850 pos = search_ref_dir(dir, dirname.buf, dirname.len); 851 852 if (pos >= 0) { 853 /* 854 * We found a directory named "$refname/" 855 * (e.g., "refs/foo/bar/"). It is a problem 856 * iff it contains any ref that is not in 857 * "skip". 858 */ 859 struct nonmatching_ref_data data; 860 861 data.skip = skip; 862 data.conflicting_refname = NULL; 863 dir = get_ref_dir(dir->entries[pos]); 864 sort_ref_dir(dir); 865 if (do_for_each_entry_in_dir(dir, 0, nonmatching_ref_fn, &data)) { 866 strbuf_addf(err, "'%s' exists; cannot create '%s'", 867 data.conflicting_refname, refname); 868 goto cleanup; 869 } 870 } 871 } 872 873 extra_refname = find_descendant_ref(dirname.buf, extras, skip); 874 if (extra_refname) 875 strbuf_addf(err, "cannot process '%s' and '%s' at the same time", 876 refname, extra_refname); 877 else 878 ret = 0; 879 880cleanup: 881 strbuf_release(&dirname); 882 return ret; 883} 884 885struct packed_ref_cache { 886 struct ref_entry *root; 887 888 /* 889 * Count of references to the data structure in this instance, 890 * including the pointer from files_ref_store::packed if any. 891 * The data will not be freed as long as the reference count 892 * is nonzero. 893 */ 894 unsigned int referrers; 895 896 /* 897 * Iff the packed-refs file associated with this instance is 898 * currently locked for writing, this points at the associated 899 * lock (which is owned by somebody else). The referrer count 900 * is also incremented when the file is locked and decremented 901 * when it is unlocked. 902 */ 903 struct lock_file *lock; 904 905 /* The metadata from when this packed-refs cache was read */ 906 struct stat_validity validity; 907}; 908 909/* 910 * Future: need to be in "struct repository" 911 * when doing a full libification. 912 */ 913struct files_ref_store { 914 struct ref_store base; 915 struct ref_entry *loose; 916 struct packed_ref_cache *packed; 917}; 918 919/* Lock used for the main packed-refs file: */ 920static struct lock_file packlock; 921 922/* 923 * Increment the reference count of *packed_refs. 924 */ 925static void acquire_packed_ref_cache(struct packed_ref_cache *packed_refs) 926{ 927 packed_refs->referrers++; 928} 929 930/* 931 * Decrease the reference count of *packed_refs. If it goes to zero, 932 * free *packed_refs and return true; otherwise return false. 933 */ 934static int release_packed_ref_cache(struct packed_ref_cache *packed_refs) 935{ 936 if (!--packed_refs->referrers) { 937 free_ref_entry(packed_refs->root); 938 stat_validity_clear(&packed_refs->validity); 939 free(packed_refs); 940 return 1; 941 } else { 942 return 0; 943 } 944} 945 946static void clear_packed_ref_cache(struct files_ref_store *refs) 947{ 948 if (refs->packed) { 949 struct packed_ref_cache *packed_refs = refs->packed; 950 951 if (packed_refs->lock) 952 die("internal error: packed-ref cache cleared while locked"); 953 refs->packed = NULL; 954 release_packed_ref_cache(packed_refs); 955 } 956} 957 958static void clear_loose_ref_cache(struct files_ref_store *refs) 959{ 960 if (refs->loose) { 961 free_ref_entry(refs->loose); 962 refs->loose = NULL; 963 } 964} 965 966/* 967 * Create a new submodule ref cache and add it to the internal 968 * set of caches. 969 */ 970static struct ref_store *files_ref_store_create(const char *submodule) 971{ 972 struct files_ref_store *refs = xcalloc(1, sizeof(*refs)); 973 struct ref_store *ref_store = (struct ref_store *)refs; 974 975 base_ref_store_init(ref_store, &refs_be_files, submodule); 976 977 return ref_store; 978} 979 980/* 981 * Downcast ref_store to files_ref_store. Die if ref_store is not a 982 * files_ref_store. If submodule_allowed is not true, then also die if 983 * files_ref_store is for a submodule (i.e., not for the main 984 * repository). caller is used in any necessary error messages. 985 */ 986static struct files_ref_store *files_downcast( 987 struct ref_store *ref_store, int submodule_allowed, 988 const char *caller) 989{ 990 if (ref_store->be != &refs_be_files) 991 die("BUG: ref_store is type \"%s\" not \"files\" in %s", 992 ref_store->be->name, caller); 993 994 if (!submodule_allowed) 995 assert_main_repository(ref_store, caller); 996 997 return (struct files_ref_store *)ref_store; 998} 9991000/*1001 * Return a pointer to the reference store for the specified1002 * submodule. For the main repository, use submodule==NULL; such a1003 * call cannot fail. For a submodule, the submodule must exist and be1004 * a nonbare repository, otherwise return NULL. Verify that the1005 * reference store is a files_ref_store, and cast it to that type1006 * before returning it.1007 */1008static struct files_ref_store *get_files_ref_store(const char *submodule,1009 const char *caller)1010{1011 struct ref_store *refs = get_ref_store(submodule);10121013 return refs ? files_downcast(refs, 1, caller) : NULL;1014}10151016/* The length of a peeled reference line in packed-refs, including EOL: */1017#define PEELED_LINE_LENGTH 4210181019/*1020 * The packed-refs header line that we write out. Perhaps other1021 * traits will be added later. The trailing space is required.1022 */1023static const char PACKED_REFS_HEADER[] =1024 "# pack-refs with: peeled fully-peeled \n";10251026/*1027 * Parse one line from a packed-refs file. Write the SHA1 to sha1.1028 * Return a pointer to the refname within the line (null-terminated),1029 * or NULL if there was a problem.1030 */1031static const char *parse_ref_line(struct strbuf *line, unsigned char *sha1)1032{1033 const char *ref;10341035 /*1036 * 42: the answer to everything.1037 *1038 * In this case, it happens to be the answer to1039 * 40 (length of sha1 hex representation)1040 * +1 (space in between hex and name)1041 * +1 (newline at the end of the line)1042 */1043 if (line->len <= 42)1044 return NULL;10451046 if (get_sha1_hex(line->buf, sha1) < 0)1047 return NULL;1048 if (!isspace(line->buf[40]))1049 return NULL;10501051 ref = line->buf + 41;1052 if (isspace(*ref))1053 return NULL;10541055 if (line->buf[line->len - 1] != '\n')1056 return NULL;1057 line->buf[--line->len] = 0;10581059 return ref;1060}10611062/*1063 * Read f, which is a packed-refs file, into dir.1064 *1065 * A comment line of the form "# pack-refs with: " may contain zero or1066 * more traits. We interpret the traits as follows:1067 *1068 * No traits:1069 *1070 * Probably no references are peeled. But if the file contains a1071 * peeled value for a reference, we will use it.1072 *1073 * peeled:1074 *1075 * References under "refs/tags/", if they *can* be peeled, *are*1076 * peeled in this file. References outside of "refs/tags/" are1077 * probably not peeled even if they could have been, but if we find1078 * a peeled value for such a reference we will use it.1079 *1080 * fully-peeled:1081 *1082 * All references in the file that can be peeled are peeled.1083 * Inversely (and this is more important), any references in the1084 * file for which no peeled value is recorded is not peelable. This1085 * trait should typically be written alongside "peeled" for1086 * compatibility with older clients, but we do not require it1087 * (i.e., "peeled" is a no-op if "fully-peeled" is set).1088 */1089static void read_packed_refs(FILE *f, struct ref_dir *dir)1090{1091 struct ref_entry *last = NULL;1092 struct strbuf line = STRBUF_INIT;1093 enum { PEELED_NONE, PEELED_TAGS, PEELED_FULLY } peeled = PEELED_NONE;10941095 while (strbuf_getwholeline(&line, f, '\n') != EOF) {1096 unsigned char sha1[20];1097 const char *refname;1098 const char *traits;10991100 if (skip_prefix(line.buf, "# pack-refs with:", &traits)) {1101 if (strstr(traits, " fully-peeled "))1102 peeled = PEELED_FULLY;1103 else if (strstr(traits, " peeled "))1104 peeled = PEELED_TAGS;1105 /* perhaps other traits later as well */1106 continue;1107 }11081109 refname = parse_ref_line(&line, sha1);1110 if (refname) {1111 int flag = REF_ISPACKED;11121113 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {1114 if (!refname_is_safe(refname))1115 die("packed refname is dangerous: %s", refname);1116 hashclr(sha1);1117 flag |= REF_BAD_NAME | REF_ISBROKEN;1118 }1119 last = create_ref_entry(refname, sha1, flag, 0);1120 if (peeled == PEELED_FULLY ||1121 (peeled == PEELED_TAGS && starts_with(refname, "refs/tags/")))1122 last->flag |= REF_KNOWS_PEELED;1123 add_ref(dir, last);1124 continue;1125 }1126 if (last &&1127 line.buf[0] == '^' &&1128 line.len == PEELED_LINE_LENGTH &&1129 line.buf[PEELED_LINE_LENGTH - 1] == '\n' &&1130 !get_sha1_hex(line.buf + 1, sha1)) {1131 hashcpy(last->u.value.peeled.hash, sha1);1132 /*1133 * Regardless of what the file header said,1134 * we definitely know the value of *this*1135 * reference:1136 */1137 last->flag |= REF_KNOWS_PEELED;1138 }1139 }11401141 strbuf_release(&line);1142}11431144/*1145 * Get the packed_ref_cache for the specified files_ref_store,1146 * creating it if necessary.1147 */1148static struct packed_ref_cache *get_packed_ref_cache(struct files_ref_store *refs)1149{1150 char *packed_refs_file;11511152 if (*refs->base.submodule)1153 packed_refs_file = git_pathdup_submodule(refs->base.submodule,1154 "packed-refs");1155 else1156 packed_refs_file = git_pathdup("packed-refs");11571158 if (refs->packed &&1159 !stat_validity_check(&refs->packed->validity, packed_refs_file))1160 clear_packed_ref_cache(refs);11611162 if (!refs->packed) {1163 FILE *f;11641165 refs->packed = xcalloc(1, sizeof(*refs->packed));1166 acquire_packed_ref_cache(refs->packed);1167 refs->packed->root = create_dir_entry(refs, "", 0, 0);1168 f = fopen(packed_refs_file, "r");1169 if (f) {1170 stat_validity_update(&refs->packed->validity, fileno(f));1171 read_packed_refs(f, get_ref_dir(refs->packed->root));1172 fclose(f);1173 }1174 }1175 free(packed_refs_file);1176 return refs->packed;1177}11781179static struct ref_dir *get_packed_ref_dir(struct packed_ref_cache *packed_ref_cache)1180{1181 return get_ref_dir(packed_ref_cache->root);1182}11831184static struct ref_dir *get_packed_refs(struct files_ref_store *refs)1185{1186 return get_packed_ref_dir(get_packed_ref_cache(refs));1187}11881189/*1190 * Add a reference to the in-memory packed reference cache. This may1191 * only be called while the packed-refs file is locked (see1192 * lock_packed_refs()). To actually write the packed-refs file, call1193 * commit_packed_refs().1194 */1195static void add_packed_ref(struct files_ref_store *refs,1196 const char *refname, const unsigned char *sha1)1197{1198 struct packed_ref_cache *packed_ref_cache = get_packed_ref_cache(refs);11991200 if (!packed_ref_cache->lock)1201 die("internal error: packed refs not locked");1202 add_ref(get_packed_ref_dir(packed_ref_cache),1203 create_ref_entry(refname, sha1, REF_ISPACKED, 1));1204}12051206/*1207 * Read the loose references from the namespace dirname into dir1208 * (without recursing). dirname must end with '/'. dir must be the1209 * directory entry corresponding to dirname.1210 */1211static void read_loose_refs(const char *dirname, struct ref_dir *dir)1212{1213 struct files_ref_store *refs = dir->ref_store;1214 DIR *d;1215 struct dirent *de;1216 int dirnamelen = strlen(dirname);1217 struct strbuf refname;1218 struct strbuf path = STRBUF_INIT;1219 size_t path_baselen;12201221 if (*refs->base.submodule)1222 strbuf_git_path_submodule(&path, refs->base.submodule, "%s", dirname);1223 else1224 strbuf_git_path(&path, "%s", dirname);1225 path_baselen = path.len;12261227 d = opendir(path.buf);1228 if (!d) {1229 strbuf_release(&path);1230 return;1231 }12321233 strbuf_init(&refname, dirnamelen + 257);1234 strbuf_add(&refname, dirname, dirnamelen);12351236 while ((de = readdir(d)) != NULL) {1237 unsigned char sha1[20];1238 struct stat st;1239 int flag;12401241 if (de->d_name[0] == '.')1242 continue;1243 if (ends_with(de->d_name, ".lock"))1244 continue;1245 strbuf_addstr(&refname, de->d_name);1246 strbuf_addstr(&path, de->d_name);1247 if (stat(path.buf, &st) < 0) {1248 ; /* silently ignore */1249 } else if (S_ISDIR(st.st_mode)) {1250 strbuf_addch(&refname, '/');1251 add_entry_to_dir(dir,1252 create_dir_entry(refs, refname.buf,1253 refname.len, 1));1254 } else {1255 int read_ok;12561257 if (*refs->base.submodule) {1258 hashclr(sha1);1259 flag = 0;1260 read_ok = !resolve_gitlink_ref(refs->base.submodule,1261 refname.buf, sha1);1262 } else {1263 read_ok = !read_ref_full(refname.buf,1264 RESOLVE_REF_READING,1265 sha1, &flag);1266 }12671268 if (!read_ok) {1269 hashclr(sha1);1270 flag |= REF_ISBROKEN;1271 } else if (is_null_sha1(sha1)) {1272 /*1273 * It is so astronomically unlikely1274 * that NULL_SHA1 is the SHA-1 of an1275 * actual object that we consider its1276 * appearance in a loose reference1277 * file to be repo corruption1278 * (probably due to a software bug).1279 */1280 flag |= REF_ISBROKEN;1281 }12821283 if (check_refname_format(refname.buf,1284 REFNAME_ALLOW_ONELEVEL)) {1285 if (!refname_is_safe(refname.buf))1286 die("loose refname is dangerous: %s", refname.buf);1287 hashclr(sha1);1288 flag |= REF_BAD_NAME | REF_ISBROKEN;1289 }1290 add_entry_to_dir(dir,1291 create_ref_entry(refname.buf, sha1, flag, 0));1292 }1293 strbuf_setlen(&refname, dirnamelen);1294 strbuf_setlen(&path, path_baselen);1295 }1296 strbuf_release(&refname);1297 strbuf_release(&path);1298 closedir(d);1299}13001301static struct ref_dir *get_loose_refs(struct files_ref_store *refs)1302{1303 if (!refs->loose) {1304 /*1305 * Mark the top-level directory complete because we1306 * are about to read the only subdirectory that can1307 * hold references:1308 */1309 refs->loose = create_dir_entry(refs, "", 0, 0);1310 /*1311 * Create an incomplete entry for "refs/":1312 */1313 add_entry_to_dir(get_ref_dir(refs->loose),1314 create_dir_entry(refs, "refs/", 5, 1));1315 }1316 return get_ref_dir(refs->loose);1317}13181319#define MAXREFLEN (1024)13201321/*1322 * Called by resolve_gitlink_ref_recursive() after it failed to read1323 * from the loose refs in refs. Find <refname> in the packed-refs file1324 * for the submodule.1325 */1326static int resolve_gitlink_packed_ref(struct files_ref_store *refs,1327 const char *refname, unsigned char *sha1)1328{1329 struct ref_entry *ref;1330 struct ref_dir *dir = get_packed_refs(refs);13311332 ref = find_ref(dir, refname);1333 if (ref == NULL)1334 return -1;13351336 hashcpy(sha1, ref->u.value.oid.hash);1337 return 0;1338}13391340static int resolve_gitlink_ref_recursive(struct files_ref_store *refs,1341 const char *refname, unsigned char *sha1,1342 int recursion)1343{1344 int fd, len;1345 char buffer[128], *p;1346 char *path;13471348 if (recursion > SYMREF_MAXDEPTH || strlen(refname) > MAXREFLEN)1349 return -1;1350 path = *refs->base.submodule1351 ? git_pathdup_submodule(refs->base.submodule, "%s", refname)1352 : git_pathdup("%s", refname);1353 fd = open(path, O_RDONLY);1354 free(path);1355 if (fd < 0)1356 return resolve_gitlink_packed_ref(refs, refname, sha1);13571358 len = read(fd, buffer, sizeof(buffer)-1);1359 close(fd);1360 if (len < 0)1361 return -1;1362 while (len && isspace(buffer[len-1]))1363 len--;1364 buffer[len] = 0;13651366 /* Was it a detached head or an old-fashioned symlink? */1367 if (!get_sha1_hex(buffer, sha1))1368 return 0;13691370 /* Symref? */1371 if (strncmp(buffer, "ref:", 4))1372 return -1;1373 p = buffer + 4;1374 while (isspace(*p))1375 p++;13761377 return resolve_gitlink_ref_recursive(refs, p, sha1, recursion+1);1378}13791380int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *sha1)1381{1382 int len = strlen(path);1383 struct strbuf submodule = STRBUF_INIT;1384 struct files_ref_store *refs;13851386 while (len && path[len-1] == '/')1387 len--;1388 if (!len)1389 return -1;13901391 strbuf_add(&submodule, path, len);1392 refs = get_files_ref_store(submodule.buf, "resolve_gitlink_ref");1393 if (!refs) {1394 strbuf_release(&submodule);1395 return -1;1396 }1397 strbuf_release(&submodule);13981399 return resolve_gitlink_ref_recursive(refs, refname, sha1, 0);1400}14011402/*1403 * Return the ref_entry for the given refname from the packed1404 * references. If it does not exist, return NULL.1405 */1406static struct ref_entry *get_packed_ref(struct files_ref_store *refs,1407 const char *refname)1408{1409 return find_ref(get_packed_refs(refs), refname);1410}14111412/*1413 * A loose ref file doesn't exist; check for a packed ref.1414 */1415static int resolve_missing_loose_ref(const char *refname,1416 unsigned char *sha1,1417 unsigned int *flags)1418{1419 struct files_ref_store *refs =1420 get_files_ref_store(NULL, "resolve_missing_loose_ref");14211422 struct ref_entry *entry;14231424 /*1425 * The loose reference file does not exist; check for a packed1426 * reference.1427 */1428 entry = get_packed_ref(refs, refname);1429 if (entry) {1430 hashcpy(sha1, entry->u.value.oid.hash);1431 *flags |= REF_ISPACKED;1432 return 0;1433 }1434 /* refname is not a packed reference. */1435 return -1;1436}14371438int read_raw_ref(const char *refname, unsigned char *sha1,1439 struct strbuf *referent, unsigned int *type)1440{1441 struct strbuf sb_contents = STRBUF_INIT;1442 struct strbuf sb_path = STRBUF_INIT;1443 const char *path;1444 const char *buf;1445 struct stat st;1446 int fd;1447 int ret = -1;1448 int save_errno;14491450 *type = 0;1451 strbuf_reset(&sb_path);1452 strbuf_git_path(&sb_path, "%s", refname);1453 path = sb_path.buf;14541455stat_ref:1456 /*1457 * We might have to loop back here to avoid a race1458 * condition: first we lstat() the file, then we try1459 * to read it as a link or as a file. But if somebody1460 * changes the type of the file (file <-> directory1461 * <-> symlink) between the lstat() and reading, then1462 * we don't want to report that as an error but rather1463 * try again starting with the lstat().1464 */14651466 if (lstat(path, &st) < 0) {1467 if (errno != ENOENT)1468 goto out;1469 if (resolve_missing_loose_ref(refname, sha1, type)) {1470 errno = ENOENT;1471 goto out;1472 }1473 ret = 0;1474 goto out;1475 }14761477 /* Follow "normalized" - ie "refs/.." symlinks by hand */1478 if (S_ISLNK(st.st_mode)) {1479 strbuf_reset(&sb_contents);1480 if (strbuf_readlink(&sb_contents, path, 0) < 0) {1481 if (errno == ENOENT || errno == EINVAL)1482 /* inconsistent with lstat; retry */1483 goto stat_ref;1484 else1485 goto out;1486 }1487 if (starts_with(sb_contents.buf, "refs/") &&1488 !check_refname_format(sb_contents.buf, 0)) {1489 strbuf_swap(&sb_contents, referent);1490 *type |= REF_ISSYMREF;1491 ret = 0;1492 goto out;1493 }1494 }14951496 /* Is it a directory? */1497 if (S_ISDIR(st.st_mode)) {1498 /*1499 * Even though there is a directory where the loose1500 * ref is supposed to be, there could still be a1501 * packed ref:1502 */1503 if (resolve_missing_loose_ref(refname, sha1, type)) {1504 errno = EISDIR;1505 goto out;1506 }1507 ret = 0;1508 goto out;1509 }15101511 /*1512 * Anything else, just open it and try to use it as1513 * a ref1514 */1515 fd = open(path, O_RDONLY);1516 if (fd < 0) {1517 if (errno == ENOENT)1518 /* inconsistent with lstat; retry */1519 goto stat_ref;1520 else1521 goto out;1522 }1523 strbuf_reset(&sb_contents);1524 if (strbuf_read(&sb_contents, fd, 256) < 0) {1525 int save_errno = errno;1526 close(fd);1527 errno = save_errno;1528 goto out;1529 }1530 close(fd);1531 strbuf_rtrim(&sb_contents);1532 buf = sb_contents.buf;1533 if (starts_with(buf, "ref:")) {1534 buf += 4;1535 while (isspace(*buf))1536 buf++;15371538 strbuf_reset(referent);1539 strbuf_addstr(referent, buf);1540 *type |= REF_ISSYMREF;1541 ret = 0;1542 goto out;1543 }15441545 /*1546 * Please note that FETCH_HEAD has additional1547 * data after the sha.1548 */1549 if (get_sha1_hex(buf, sha1) ||1550 (buf[40] != '\0' && !isspace(buf[40]))) {1551 *type |= REF_ISBROKEN;1552 errno = EINVAL;1553 goto out;1554 }15551556 ret = 0;15571558out:1559 save_errno = errno;1560 strbuf_release(&sb_path);1561 strbuf_release(&sb_contents);1562 errno = save_errno;1563 return ret;1564}15651566static void unlock_ref(struct ref_lock *lock)1567{1568 /* Do not free lock->lk -- atexit() still looks at them */1569 if (lock->lk)1570 rollback_lock_file(lock->lk);1571 free(lock->ref_name);1572 free(lock);1573}15741575/*1576 * Lock refname, without following symrefs, and set *lock_p to point1577 * at a newly-allocated lock object. Fill in lock->old_oid, referent,1578 * and type similarly to read_raw_ref().1579 *1580 * The caller must verify that refname is a "safe" reference name (in1581 * the sense of refname_is_safe()) before calling this function.1582 *1583 * If the reference doesn't already exist, verify that refname doesn't1584 * have a D/F conflict with any existing references. extras and skip1585 * are passed to verify_refname_available_dir() for this check.1586 *1587 * If mustexist is not set and the reference is not found or is1588 * broken, lock the reference anyway but clear sha1.1589 *1590 * Return 0 on success. On failure, write an error message to err and1591 * return TRANSACTION_NAME_CONFLICT or TRANSACTION_GENERIC_ERROR.1592 *1593 * Implementation note: This function is basically1594 *1595 * lock reference1596 * read_raw_ref()1597 *1598 * but it includes a lot more code to1599 * - Deal with possible races with other processes1600 * - Avoid calling verify_refname_available_dir() when it can be1601 * avoided, namely if we were successfully able to read the ref1602 * - Generate informative error messages in the case of failure1603 */1604static int lock_raw_ref(const char *refname, int mustexist,1605 const struct string_list *extras,1606 const struct string_list *skip,1607 struct ref_lock **lock_p,1608 struct strbuf *referent,1609 unsigned int *type,1610 struct strbuf *err)1611{1612 struct files_ref_store *refs =1613 get_files_ref_store(NULL, "lock_raw_ref");1614 struct ref_lock *lock;1615 struct strbuf ref_file = STRBUF_INIT;1616 int attempts_remaining = 3;1617 int ret = TRANSACTION_GENERIC_ERROR;16181619 assert(err);1620 *type = 0;16211622 /* First lock the file so it can't change out from under us. */16231624 *lock_p = lock = xcalloc(1, sizeof(*lock));16251626 lock->ref_name = xstrdup(refname);1627 strbuf_git_path(&ref_file, "%s", refname);16281629retry:1630 switch (safe_create_leading_directories(ref_file.buf)) {1631 case SCLD_OK:1632 break; /* success */1633 case SCLD_EXISTS:1634 /*1635 * Suppose refname is "refs/foo/bar". We just failed1636 * to create the containing directory, "refs/foo",1637 * because there was a non-directory in the way. This1638 * indicates a D/F conflict, probably because of1639 * another reference such as "refs/foo". There is no1640 * reason to expect this error to be transitory.1641 */1642 if (verify_refname_available(refname, extras, skip, err)) {1643 if (mustexist) {1644 /*1645 * To the user the relevant error is1646 * that the "mustexist" reference is1647 * missing:1648 */1649 strbuf_reset(err);1650 strbuf_addf(err, "unable to resolve reference '%s'",1651 refname);1652 } else {1653 /*1654 * The error message set by1655 * verify_refname_available_dir() is OK.1656 */1657 ret = TRANSACTION_NAME_CONFLICT;1658 }1659 } else {1660 /*1661 * The file that is in the way isn't a loose1662 * reference. Report it as a low-level1663 * failure.1664 */1665 strbuf_addf(err, "unable to create lock file %s.lock; "1666 "non-directory in the way",1667 ref_file.buf);1668 }1669 goto error_return;1670 case SCLD_VANISHED:1671 /* Maybe another process was tidying up. Try again. */1672 if (--attempts_remaining > 0)1673 goto retry;1674 /* fall through */1675 default:1676 strbuf_addf(err, "unable to create directory for %s",1677 ref_file.buf);1678 goto error_return;1679 }16801681 if (!lock->lk)1682 lock->lk = xcalloc(1, sizeof(struct lock_file));16831684 if (hold_lock_file_for_update(lock->lk, ref_file.buf, LOCK_NO_DEREF) < 0) {1685 if (errno == ENOENT && --attempts_remaining > 0) {1686 /*1687 * Maybe somebody just deleted one of the1688 * directories leading to ref_file. Try1689 * again:1690 */1691 goto retry;1692 } else {1693 unable_to_lock_message(ref_file.buf, errno, err);1694 goto error_return;1695 }1696 }16971698 /*1699 * Now we hold the lock and can read the reference without1700 * fear that its value will change.1701 */17021703 if (read_raw_ref(refname, lock->old_oid.hash, referent, type)) {1704 if (errno == ENOENT) {1705 if (mustexist) {1706 /* Garden variety missing reference. */1707 strbuf_addf(err, "unable to resolve reference '%s'",1708 refname);1709 goto error_return;1710 } else {1711 /*1712 * Reference is missing, but that's OK. We1713 * know that there is not a conflict with1714 * another loose reference because1715 * (supposing that we are trying to lock1716 * reference "refs/foo/bar"):1717 *1718 * - We were successfully able to create1719 * the lockfile refs/foo/bar.lock, so we1720 * know there cannot be a loose reference1721 * named "refs/foo".1722 *1723 * - We got ENOENT and not EISDIR, so we1724 * know that there cannot be a loose1725 * reference named "refs/foo/bar/baz".1726 */1727 }1728 } else if (errno == EISDIR) {1729 /*1730 * There is a directory in the way. It might have1731 * contained references that have been deleted. If1732 * we don't require that the reference already1733 * exists, try to remove the directory so that it1734 * doesn't cause trouble when we want to rename the1735 * lockfile into place later.1736 */1737 if (mustexist) {1738 /* Garden variety missing reference. */1739 strbuf_addf(err, "unable to resolve reference '%s'",1740 refname);1741 goto error_return;1742 } else if (remove_dir_recursively(&ref_file,1743 REMOVE_DIR_EMPTY_ONLY)) {1744 if (verify_refname_available_dir(1745 refname, extras, skip,1746 get_loose_refs(refs),1747 err)) {1748 /*1749 * The error message set by1750 * verify_refname_available() is OK.1751 */1752 ret = TRANSACTION_NAME_CONFLICT;1753 goto error_return;1754 } else {1755 /*1756 * We can't delete the directory,1757 * but we also don't know of any1758 * references that it should1759 * contain.1760 */1761 strbuf_addf(err, "there is a non-empty directory '%s' "1762 "blocking reference '%s'",1763 ref_file.buf, refname);1764 goto error_return;1765 }1766 }1767 } else if (errno == EINVAL && (*type & REF_ISBROKEN)) {1768 strbuf_addf(err, "unable to resolve reference '%s': "1769 "reference broken", refname);1770 goto error_return;1771 } else {1772 strbuf_addf(err, "unable to resolve reference '%s': %s",1773 refname, strerror(errno));1774 goto error_return;1775 }17761777 /*1778 * If the ref did not exist and we are creating it,1779 * make sure there is no existing packed ref whose1780 * name begins with our refname, nor a packed ref1781 * whose name is a proper prefix of our refname.1782 */1783 if (verify_refname_available_dir(1784 refname, extras, skip,1785 get_packed_refs(refs),1786 err)) {1787 goto error_return;1788 }1789 }17901791 ret = 0;1792 goto out;17931794error_return:1795 unlock_ref(lock);1796 *lock_p = NULL;17971798out:1799 strbuf_release(&ref_file);1800 return ret;1801}18021803/*1804 * Peel the entry (if possible) and return its new peel_status. If1805 * repeel is true, re-peel the entry even if there is an old peeled1806 * value that is already stored in it.1807 *1808 * It is OK to call this function with a packed reference entry that1809 * might be stale and might even refer to an object that has since1810 * been garbage-collected. In such a case, if the entry has1811 * REF_KNOWS_PEELED then leave the status unchanged and return1812 * PEEL_PEELED or PEEL_NON_TAG; otherwise, return PEEL_INVALID.1813 */1814static enum peel_status peel_entry(struct ref_entry *entry, int repeel)1815{1816 enum peel_status status;18171818 if (entry->flag & REF_KNOWS_PEELED) {1819 if (repeel) {1820 entry->flag &= ~REF_KNOWS_PEELED;1821 oidclr(&entry->u.value.peeled);1822 } else {1823 return is_null_oid(&entry->u.value.peeled) ?1824 PEEL_NON_TAG : PEEL_PEELED;1825 }1826 }1827 if (entry->flag & REF_ISBROKEN)1828 return PEEL_BROKEN;1829 if (entry->flag & REF_ISSYMREF)1830 return PEEL_IS_SYMREF;18311832 status = peel_object(entry->u.value.oid.hash, entry->u.value.peeled.hash);1833 if (status == PEEL_PEELED || status == PEEL_NON_TAG)1834 entry->flag |= REF_KNOWS_PEELED;1835 return status;1836}18371838int peel_ref(const char *refname, unsigned char *sha1)1839{1840 struct files_ref_store *refs = get_files_ref_store(NULL, "peel_ref");1841 int flag;1842 unsigned char base[20];18431844 if (current_ref_iter && current_ref_iter->refname == refname) {1845 struct object_id peeled;18461847 if (ref_iterator_peel(current_ref_iter, &peeled))1848 return -1;1849 hashcpy(sha1, peeled.hash);1850 return 0;1851 }18521853 if (read_ref_full(refname, RESOLVE_REF_READING, base, &flag))1854 return -1;18551856 /*1857 * If the reference is packed, read its ref_entry from the1858 * cache in the hope that we already know its peeled value.1859 * We only try this optimization on packed references because1860 * (a) forcing the filling of the loose reference cache could1861 * be expensive and (b) loose references anyway usually do not1862 * have REF_KNOWS_PEELED.1863 */1864 if (flag & REF_ISPACKED) {1865 struct ref_entry *r = get_packed_ref(refs, refname);1866 if (r) {1867 if (peel_entry(r, 0))1868 return -1;1869 hashcpy(sha1, r->u.value.peeled.hash);1870 return 0;1871 }1872 }18731874 return peel_object(base, sha1);1875}18761877struct files_ref_iterator {1878 struct ref_iterator base;18791880 struct packed_ref_cache *packed_ref_cache;1881 struct ref_iterator *iter0;1882 unsigned int flags;1883};18841885static int files_ref_iterator_advance(struct ref_iterator *ref_iterator)1886{1887 struct files_ref_iterator *iter =1888 (struct files_ref_iterator *)ref_iterator;1889 int ok;18901891 while ((ok = ref_iterator_advance(iter->iter0)) == ITER_OK) {1892 if (!(iter->flags & DO_FOR_EACH_INCLUDE_BROKEN) &&1893 !ref_resolves_to_object(iter->iter0->refname,1894 iter->iter0->oid,1895 iter->iter0->flags))1896 continue;18971898 iter->base.refname = iter->iter0->refname;1899 iter->base.oid = iter->iter0->oid;1900 iter->base.flags = iter->iter0->flags;1901 return ITER_OK;1902 }19031904 iter->iter0 = NULL;1905 if (ref_iterator_abort(ref_iterator) != ITER_DONE)1906 ok = ITER_ERROR;19071908 return ok;1909}19101911static int files_ref_iterator_peel(struct ref_iterator *ref_iterator,1912 struct object_id *peeled)1913{1914 struct files_ref_iterator *iter =1915 (struct files_ref_iterator *)ref_iterator;19161917 return ref_iterator_peel(iter->iter0, peeled);1918}19191920static int files_ref_iterator_abort(struct ref_iterator *ref_iterator)1921{1922 struct files_ref_iterator *iter =1923 (struct files_ref_iterator *)ref_iterator;1924 int ok = ITER_DONE;19251926 if (iter->iter0)1927 ok = ref_iterator_abort(iter->iter0);19281929 release_packed_ref_cache(iter->packed_ref_cache);1930 base_ref_iterator_free(ref_iterator);1931 return ok;1932}19331934static struct ref_iterator_vtable files_ref_iterator_vtable = {1935 files_ref_iterator_advance,1936 files_ref_iterator_peel,1937 files_ref_iterator_abort1938};19391940struct ref_iterator *files_ref_iterator_begin(1941 const char *submodule,1942 const char *prefix, unsigned int flags)1943{1944 struct files_ref_store *refs =1945 get_files_ref_store(submodule, "ref_iterator_begin");1946 struct ref_dir *loose_dir, *packed_dir;1947 struct ref_iterator *loose_iter, *packed_iter;1948 struct files_ref_iterator *iter;1949 struct ref_iterator *ref_iterator;19501951 if (!refs)1952 return empty_ref_iterator_begin();19531954 if (ref_paranoia < 0)1955 ref_paranoia = git_env_bool("GIT_REF_PARANOIA", 0);1956 if (ref_paranoia)1957 flags |= DO_FOR_EACH_INCLUDE_BROKEN;19581959 iter = xcalloc(1, sizeof(*iter));1960 ref_iterator = &iter->base;1961 base_ref_iterator_init(ref_iterator, &files_ref_iterator_vtable);19621963 /*1964 * We must make sure that all loose refs are read before1965 * accessing the packed-refs file; this avoids a race1966 * condition if loose refs are migrated to the packed-refs1967 * file by a simultaneous process, but our in-memory view is1968 * from before the migration. We ensure this as follows:1969 * First, we call prime_ref_dir(), which pre-reads the loose1970 * references for the subtree into the cache. (If they've1971 * already been read, that's OK; we only need to guarantee1972 * that they're read before the packed refs, not *how much*1973 * before.) After that, we call get_packed_ref_cache(), which1974 * internally checks whether the packed-ref cache is up to1975 * date with what is on disk, and re-reads it if not.1976 */19771978 loose_dir = get_loose_refs(refs);19791980 if (prefix && *prefix)1981 loose_dir = find_containing_dir(loose_dir, prefix, 0);19821983 if (loose_dir) {1984 prime_ref_dir(loose_dir);1985 loose_iter = cache_ref_iterator_begin(loose_dir);1986 } else {1987 /* There's nothing to iterate over. */1988 loose_iter = empty_ref_iterator_begin();1989 }19901991 iter->packed_ref_cache = get_packed_ref_cache(refs);1992 acquire_packed_ref_cache(iter->packed_ref_cache);1993 packed_dir = get_packed_ref_dir(iter->packed_ref_cache);19941995 if (prefix && *prefix)1996 packed_dir = find_containing_dir(packed_dir, prefix, 0);19971998 if (packed_dir) {1999 packed_iter = cache_ref_iterator_begin(packed_dir);2000 } else {2001 /* There's nothing to iterate over. */2002 packed_iter = empty_ref_iterator_begin();2003 }20042005 iter->iter0 = overlay_ref_iterator_begin(loose_iter, packed_iter);2006 iter->flags = flags;20072008 return ref_iterator;2009}20102011/*2012 * Verify that the reference locked by lock has the value old_sha1.2013 * Fail if the reference doesn't exist and mustexist is set. Return 02014 * on success. On error, write an error message to err, set errno, and2015 * return a negative value.2016 */2017static int verify_lock(struct ref_lock *lock,2018 const unsigned char *old_sha1, int mustexist,2019 struct strbuf *err)2020{2021 assert(err);20222023 if (read_ref_full(lock->ref_name,2024 mustexist ? RESOLVE_REF_READING : 0,2025 lock->old_oid.hash, NULL)) {2026 if (old_sha1) {2027 int save_errno = errno;2028 strbuf_addf(err, "can't verify ref '%s'", lock->ref_name);2029 errno = save_errno;2030 return -1;2031 } else {2032 hashclr(lock->old_oid.hash);2033 return 0;2034 }2035 }2036 if (old_sha1 && hashcmp(lock->old_oid.hash, old_sha1)) {2037 strbuf_addf(err, "ref '%s' is at %s but expected %s",2038 lock->ref_name,2039 sha1_to_hex(lock->old_oid.hash),2040 sha1_to_hex(old_sha1));2041 errno = EBUSY;2042 return -1;2043 }2044 return 0;2045}20462047static int remove_empty_directories(struct strbuf *path)2048{2049 /*2050 * we want to create a file but there is a directory there;2051 * if that is an empty directory (or a directory that contains2052 * only empty directories), remove them.2053 */2054 return remove_dir_recursively(path, REMOVE_DIR_EMPTY_ONLY);2055}20562057/*2058 * Locks a ref returning the lock on success and NULL on failure.2059 * On failure errno is set to something meaningful.2060 */2061static struct ref_lock *lock_ref_sha1_basic(const char *refname,2062 const unsigned char *old_sha1,2063 const struct string_list *extras,2064 const struct string_list *skip,2065 unsigned int flags, int *type,2066 struct strbuf *err)2067{2068 struct files_ref_store *refs =2069 get_files_ref_store(NULL, "lock_ref_sha1_basic");2070 struct strbuf ref_file = STRBUF_INIT;2071 struct ref_lock *lock;2072 int last_errno = 0;2073 int lflags = LOCK_NO_DEREF;2074 int mustexist = (old_sha1 && !is_null_sha1(old_sha1));2075 int resolve_flags = RESOLVE_REF_NO_RECURSE;2076 int attempts_remaining = 3;2077 int resolved;20782079 assert(err);20802081 lock = xcalloc(1, sizeof(struct ref_lock));20822083 if (mustexist)2084 resolve_flags |= RESOLVE_REF_READING;2085 if (flags & REF_DELETING)2086 resolve_flags |= RESOLVE_REF_ALLOW_BAD_NAME;20872088 strbuf_git_path(&ref_file, "%s", refname);2089 resolved = !!resolve_ref_unsafe(refname, resolve_flags,2090 lock->old_oid.hash, type);2091 if (!resolved && errno == EISDIR) {2092 /*2093 * we are trying to lock foo but we used to2094 * have foo/bar which now does not exist;2095 * it is normal for the empty directory 'foo'2096 * to remain.2097 */2098 if (remove_empty_directories(&ref_file)) {2099 last_errno = errno;2100 if (!verify_refname_available_dir(2101 refname, extras, skip,2102 get_loose_refs(refs), err))2103 strbuf_addf(err, "there are still refs under '%s'",2104 refname);2105 goto error_return;2106 }2107 resolved = !!resolve_ref_unsafe(refname, resolve_flags,2108 lock->old_oid.hash, type);2109 }2110 if (!resolved) {2111 last_errno = errno;2112 if (last_errno != ENOTDIR ||2113 !verify_refname_available_dir(2114 refname, extras, skip,2115 get_loose_refs(refs), err))2116 strbuf_addf(err, "unable to resolve reference '%s': %s",2117 refname, strerror(last_errno));21182119 goto error_return;2120 }21212122 /*2123 * If the ref did not exist and we are creating it, make sure2124 * there is no existing packed ref whose name begins with our2125 * refname, nor a packed ref whose name is a proper prefix of2126 * our refname.2127 */2128 if (is_null_oid(&lock->old_oid) &&2129 verify_refname_available_dir(refname, extras, skip,2130 get_packed_refs(refs),2131 err)) {2132 last_errno = ENOTDIR;2133 goto error_return;2134 }21352136 lock->lk = xcalloc(1, sizeof(struct lock_file));21372138 lock->ref_name = xstrdup(refname);21392140 retry:2141 switch (safe_create_leading_directories_const(ref_file.buf)) {2142 case SCLD_OK:2143 break; /* success */2144 case SCLD_VANISHED:2145 if (--attempts_remaining > 0)2146 goto retry;2147 /* fall through */2148 default:2149 last_errno = errno;2150 strbuf_addf(err, "unable to create directory for '%s'",2151 ref_file.buf);2152 goto error_return;2153 }21542155 if (hold_lock_file_for_update(lock->lk, ref_file.buf, lflags) < 0) {2156 last_errno = errno;2157 if (errno == ENOENT && --attempts_remaining > 0)2158 /*2159 * Maybe somebody just deleted one of the2160 * directories leading to ref_file. Try2161 * again:2162 */2163 goto retry;2164 else {2165 unable_to_lock_message(ref_file.buf, errno, err);2166 goto error_return;2167 }2168 }2169 if (verify_lock(lock, old_sha1, mustexist, err)) {2170 last_errno = errno;2171 goto error_return;2172 }2173 goto out;21742175 error_return:2176 unlock_ref(lock);2177 lock = NULL;21782179 out:2180 strbuf_release(&ref_file);2181 errno = last_errno;2182 return lock;2183}21842185/*2186 * Write an entry to the packed-refs file for the specified refname.2187 * If peeled is non-NULL, write it as the entry's peeled value.2188 */2189static void write_packed_entry(FILE *fh, char *refname, unsigned char *sha1,2190 unsigned char *peeled)2191{2192 fprintf_or_die(fh, "%s %s\n", sha1_to_hex(sha1), refname);2193 if (peeled)2194 fprintf_or_die(fh, "^%s\n", sha1_to_hex(peeled));2195}21962197/*2198 * An each_ref_entry_fn that writes the entry to a packed-refs file.2199 */2200static int write_packed_entry_fn(struct ref_entry *entry, void *cb_data)2201{2202 enum peel_status peel_status = peel_entry(entry, 0);22032204 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)2205 error("internal error: %s is not a valid packed reference!",2206 entry->name);2207 write_packed_entry(cb_data, entry->name, entry->u.value.oid.hash,2208 peel_status == PEEL_PEELED ?2209 entry->u.value.peeled.hash : NULL);2210 return 0;2211}22122213/*2214 * Lock the packed-refs file for writing. Flags is passed to2215 * hold_lock_file_for_update(). Return 0 on success. On errors, set2216 * errno appropriately and return a nonzero value.2217 */2218static int lock_packed_refs(int flags)2219{2220 struct files_ref_store *refs =2221 get_files_ref_store(NULL, "lock_packed_refs");2222 static int timeout_configured = 0;2223 static int timeout_value = 1000;2224 struct packed_ref_cache *packed_ref_cache;22252226 if (!timeout_configured) {2227 git_config_get_int("core.packedrefstimeout", &timeout_value);2228 timeout_configured = 1;2229 }22302231 if (hold_lock_file_for_update_timeout(2232 &packlock, git_path("packed-refs"),2233 flags, timeout_value) < 0)2234 return -1;2235 /*2236 * Get the current packed-refs while holding the lock. If the2237 * packed-refs file has been modified since we last read it,2238 * this will automatically invalidate the cache and re-read2239 * the packed-refs file.2240 */2241 packed_ref_cache = get_packed_ref_cache(refs);2242 packed_ref_cache->lock = &packlock;2243 /* Increment the reference count to prevent it from being freed: */2244 acquire_packed_ref_cache(packed_ref_cache);2245 return 0;2246}22472248/*2249 * Write the current version of the packed refs cache from memory to2250 * disk. The packed-refs file must already be locked for writing (see2251 * lock_packed_refs()). Return zero on success. On errors, set errno2252 * and return a nonzero value2253 */2254static int commit_packed_refs(void)2255{2256 struct files_ref_store *refs =2257 get_files_ref_store(NULL, "commit_packed_refs");2258 struct packed_ref_cache *packed_ref_cache =2259 get_packed_ref_cache(refs);2260 int error = 0;2261 int save_errno = 0;2262 FILE *out;22632264 if (!packed_ref_cache->lock)2265 die("internal error: packed-refs not locked");22662267 out = fdopen_lock_file(packed_ref_cache->lock, "w");2268 if (!out)2269 die_errno("unable to fdopen packed-refs descriptor");22702271 fprintf_or_die(out, "%s", PACKED_REFS_HEADER);2272 do_for_each_entry_in_dir(get_packed_ref_dir(packed_ref_cache),2273 0, write_packed_entry_fn, out);22742275 if (commit_lock_file(packed_ref_cache->lock)) {2276 save_errno = errno;2277 error = -1;2278 }2279 packed_ref_cache->lock = NULL;2280 release_packed_ref_cache(packed_ref_cache);2281 errno = save_errno;2282 return error;2283}22842285/*2286 * Rollback the lockfile for the packed-refs file, and discard the2287 * in-memory packed reference cache. (The packed-refs file will be2288 * read anew if it is needed again after this function is called.)2289 */2290static void rollback_packed_refs(void)2291{2292 struct files_ref_store *refs =2293 get_files_ref_store(NULL, "rollback_packed_refs");2294 struct packed_ref_cache *packed_ref_cache =2295 get_packed_ref_cache(refs);22962297 if (!packed_ref_cache->lock)2298 die("internal error: packed-refs not locked");2299 rollback_lock_file(packed_ref_cache->lock);2300 packed_ref_cache->lock = NULL;2301 release_packed_ref_cache(packed_ref_cache);2302 clear_packed_ref_cache(refs);2303}23042305struct ref_to_prune {2306 struct ref_to_prune *next;2307 unsigned char sha1[20];2308 char name[FLEX_ARRAY];2309};23102311struct pack_refs_cb_data {2312 unsigned int flags;2313 struct ref_dir *packed_refs;2314 struct ref_to_prune *ref_to_prune;2315};23162317/*2318 * An each_ref_entry_fn that is run over loose references only. If2319 * the loose reference can be packed, add an entry in the packed ref2320 * cache. If the reference should be pruned, also add it to2321 * ref_to_prune in the pack_refs_cb_data.2322 */2323static int pack_if_possible_fn(struct ref_entry *entry, void *cb_data)2324{2325 struct pack_refs_cb_data *cb = cb_data;2326 enum peel_status peel_status;2327 struct ref_entry *packed_entry;2328 int is_tag_ref = starts_with(entry->name, "refs/tags/");23292330 /* Do not pack per-worktree refs: */2331 if (ref_type(entry->name) != REF_TYPE_NORMAL)2332 return 0;23332334 /* ALWAYS pack tags */2335 if (!(cb->flags & PACK_REFS_ALL) && !is_tag_ref)2336 return 0;23372338 /* Do not pack symbolic or broken refs: */2339 if ((entry->flag & REF_ISSYMREF) || !entry_resolves_to_object(entry))2340 return 0;23412342 /* Add a packed ref cache entry equivalent to the loose entry. */2343 peel_status = peel_entry(entry, 1);2344 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)2345 die("internal error peeling reference %s (%s)",2346 entry->name, oid_to_hex(&entry->u.value.oid));2347 packed_entry = find_ref(cb->packed_refs, entry->name);2348 if (packed_entry) {2349 /* Overwrite existing packed entry with info from loose entry */2350 packed_entry->flag = REF_ISPACKED | REF_KNOWS_PEELED;2351 oidcpy(&packed_entry->u.value.oid, &entry->u.value.oid);2352 } else {2353 packed_entry = create_ref_entry(entry->name, entry->u.value.oid.hash,2354 REF_ISPACKED | REF_KNOWS_PEELED, 0);2355 add_ref(cb->packed_refs, packed_entry);2356 }2357 oidcpy(&packed_entry->u.value.peeled, &entry->u.value.peeled);23582359 /* Schedule the loose reference for pruning if requested. */2360 if ((cb->flags & PACK_REFS_PRUNE)) {2361 struct ref_to_prune *n;2362 FLEX_ALLOC_STR(n, name, entry->name);2363 hashcpy(n->sha1, entry->u.value.oid.hash);2364 n->next = cb->ref_to_prune;2365 cb->ref_to_prune = n;2366 }2367 return 0;2368}23692370/*2371 * Remove empty parents, but spare refs/ and immediate subdirs.2372 * Note: munges *name.2373 */2374static void try_remove_empty_parents(char *name)2375{2376 char *p, *q;2377 int i;2378 p = name;2379 for (i = 0; i < 2; i++) { /* refs/{heads,tags,...}/ */2380 while (*p && *p != '/')2381 p++;2382 /* tolerate duplicate slashes; see check_refname_format() */2383 while (*p == '/')2384 p++;2385 }2386 for (q = p; *q; q++)2387 ;2388 while (1) {2389 while (q > p && *q != '/')2390 q--;2391 while (q > p && *(q-1) == '/')2392 q--;2393 if (q == p)2394 break;2395 *q = '\0';2396 if (rmdir(git_path("%s", name)))2397 break;2398 }2399}24002401/* make sure nobody touched the ref, and unlink */2402static void prune_ref(struct ref_to_prune *r)2403{2404 struct ref_transaction *transaction;2405 struct strbuf err = STRBUF_INIT;24062407 if (check_refname_format(r->name, 0))2408 return;24092410 transaction = ref_transaction_begin(&err);2411 if (!transaction ||2412 ref_transaction_delete(transaction, r->name, r->sha1,2413 REF_ISPRUNING | REF_NODEREF, NULL, &err) ||2414 ref_transaction_commit(transaction, &err)) {2415 ref_transaction_free(transaction);2416 error("%s", err.buf);2417 strbuf_release(&err);2418 return;2419 }2420 ref_transaction_free(transaction);2421 strbuf_release(&err);2422 try_remove_empty_parents(r->name);2423}24242425static void prune_refs(struct ref_to_prune *r)2426{2427 while (r) {2428 prune_ref(r);2429 r = r->next;2430 }2431}24322433int pack_refs(unsigned int flags)2434{2435 struct files_ref_store *refs =2436 get_files_ref_store(NULL, "pack_refs");2437 struct pack_refs_cb_data cbdata;24382439 memset(&cbdata, 0, sizeof(cbdata));2440 cbdata.flags = flags;24412442 lock_packed_refs(LOCK_DIE_ON_ERROR);2443 cbdata.packed_refs = get_packed_refs(refs);24442445 do_for_each_entry_in_dir(get_loose_refs(refs), 0,2446 pack_if_possible_fn, &cbdata);24472448 if (commit_packed_refs())2449 die_errno("unable to overwrite old ref-pack file");24502451 prune_refs(cbdata.ref_to_prune);2452 return 0;2453}24542455/*2456 * Rewrite the packed-refs file, omitting any refs listed in2457 * 'refnames'. On error, leave packed-refs unchanged, write an error2458 * message to 'err', and return a nonzero value.2459 *2460 * The refs in 'refnames' needn't be sorted. `err` must not be NULL.2461 */2462static int repack_without_refs(struct string_list *refnames, struct strbuf *err)2463{2464 struct files_ref_store *refs =2465 get_files_ref_store(NULL, "repack_without_refs");2466 struct ref_dir *packed;2467 struct string_list_item *refname;2468 int ret, needs_repacking = 0, removed = 0;24692470 assert(err);24712472 /* Look for a packed ref */2473 for_each_string_list_item(refname, refnames) {2474 if (get_packed_ref(refs, refname->string)) {2475 needs_repacking = 1;2476 break;2477 }2478 }24792480 /* Avoid locking if we have nothing to do */2481 if (!needs_repacking)2482 return 0; /* no refname exists in packed refs */24832484 if (lock_packed_refs(0)) {2485 unable_to_lock_message(git_path("packed-refs"), errno, err);2486 return -1;2487 }2488 packed = get_packed_refs(refs);24892490 /* Remove refnames from the cache */2491 for_each_string_list_item(refname, refnames)2492 if (remove_entry(packed, refname->string) != -1)2493 removed = 1;2494 if (!removed) {2495 /*2496 * All packed entries disappeared while we were2497 * acquiring the lock.2498 */2499 rollback_packed_refs();2500 return 0;2501 }25022503 /* Write what remains */2504 ret = commit_packed_refs();2505 if (ret)2506 strbuf_addf(err, "unable to overwrite old ref-pack file: %s",2507 strerror(errno));2508 return ret;2509}25102511static int delete_ref_loose(struct ref_lock *lock, int flag, struct strbuf *err)2512{2513 assert(err);25142515 if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {2516 /*2517 * loose. The loose file name is the same as the2518 * lockfile name, minus ".lock":2519 */2520 char *loose_filename = get_locked_file_path(lock->lk);2521 int res = unlink_or_msg(loose_filename, err);2522 free(loose_filename);2523 if (res)2524 return 1;2525 }2526 return 0;2527}25282529int delete_refs(struct string_list *refnames, unsigned int flags)2530{2531 struct strbuf err = STRBUF_INIT;2532 int i, result = 0;25332534 if (!refnames->nr)2535 return 0;25362537 result = repack_without_refs(refnames, &err);2538 if (result) {2539 /*2540 * If we failed to rewrite the packed-refs file, then2541 * it is unsafe to try to remove loose refs, because2542 * doing so might expose an obsolete packed value for2543 * a reference that might even point at an object that2544 * has been garbage collected.2545 */2546 if (refnames->nr == 1)2547 error(_("could not delete reference %s: %s"),2548 refnames->items[0].string, err.buf);2549 else2550 error(_("could not delete references: %s"), err.buf);25512552 goto out;2553 }25542555 for (i = 0; i < refnames->nr; i++) {2556 const char *refname = refnames->items[i].string;25572558 if (delete_ref(refname, NULL, flags))2559 result |= error(_("could not remove reference %s"), refname);2560 }25612562out:2563 strbuf_release(&err);2564 return result;2565}25662567/*2568 * People using contrib's git-new-workdir have .git/logs/refs ->2569 * /some/other/path/.git/logs/refs, and that may live on another device.2570 *2571 * IOW, to avoid cross device rename errors, the temporary renamed log must2572 * live into logs/refs.2573 */2574#define TMP_RENAMED_LOG "logs/refs/.tmp-renamed-log"25752576static int rename_tmp_log(const char *newrefname)2577{2578 int attempts_remaining = 4;2579 struct strbuf path = STRBUF_INIT;2580 int ret = -1;25812582 retry:2583 strbuf_reset(&path);2584 strbuf_git_path(&path, "logs/%s", newrefname);2585 switch (safe_create_leading_directories_const(path.buf)) {2586 case SCLD_OK:2587 break; /* success */2588 case SCLD_VANISHED:2589 if (--attempts_remaining > 0)2590 goto retry;2591 /* fall through */2592 default:2593 error("unable to create directory for %s", newrefname);2594 goto out;2595 }25962597 if (rename(git_path(TMP_RENAMED_LOG), path.buf)) {2598 if ((errno==EISDIR || errno==ENOTDIR) && --attempts_remaining > 0) {2599 /*2600 * rename(a, b) when b is an existing2601 * directory ought to result in ISDIR, but2602 * Solaris 5.8 gives ENOTDIR. Sheesh.2603 */2604 if (remove_empty_directories(&path)) {2605 error("Directory not empty: logs/%s", newrefname);2606 goto out;2607 }2608 goto retry;2609 } else if (errno == ENOENT && --attempts_remaining > 0) {2610 /*2611 * Maybe another process just deleted one of2612 * the directories in the path to newrefname.2613 * Try again from the beginning.2614 */2615 goto retry;2616 } else {2617 error("unable to move logfile "TMP_RENAMED_LOG" to logs/%s: %s",2618 newrefname, strerror(errno));2619 goto out;2620 }2621 }2622 ret = 0;2623out:2624 strbuf_release(&path);2625 return ret;2626}26272628int verify_refname_available(const char *newname,2629 const struct string_list *extras,2630 const struct string_list *skip,2631 struct strbuf *err)2632{2633 struct files_ref_store *refs =2634 get_files_ref_store(NULL, "verify_refname_available");2635 struct ref_dir *packed_refs = get_packed_refs(refs);2636 struct ref_dir *loose_refs = get_loose_refs(refs);26372638 if (verify_refname_available_dir(newname, extras, skip,2639 packed_refs, err) ||2640 verify_refname_available_dir(newname, extras, skip,2641 loose_refs, err))2642 return -1;26432644 return 0;2645}26462647static int write_ref_to_lockfile(struct ref_lock *lock,2648 const unsigned char *sha1, struct strbuf *err);2649static int commit_ref_update(struct ref_lock *lock,2650 const unsigned char *sha1, const char *logmsg,2651 struct strbuf *err);26522653int rename_ref(const char *oldrefname, const char *newrefname, const char *logmsg)2654{2655 unsigned char sha1[20], orig_sha1[20];2656 int flag = 0, logmoved = 0;2657 struct ref_lock *lock;2658 struct stat loginfo;2659 int log = !lstat(git_path("logs/%s", oldrefname), &loginfo);2660 struct strbuf err = STRBUF_INIT;26612662 if (log && S_ISLNK(loginfo.st_mode))2663 return error("reflog for %s is a symlink", oldrefname);26642665 if (!resolve_ref_unsafe(oldrefname, RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,2666 orig_sha1, &flag))2667 return error("refname %s not found", oldrefname);26682669 if (flag & REF_ISSYMREF)2670 return error("refname %s is a symbolic ref, renaming it is not supported",2671 oldrefname);2672 if (!rename_ref_available(oldrefname, newrefname))2673 return 1;26742675 if (log && rename(git_path("logs/%s", oldrefname), git_path(TMP_RENAMED_LOG)))2676 return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",2677 oldrefname, strerror(errno));26782679 if (delete_ref(oldrefname, orig_sha1, REF_NODEREF)) {2680 error("unable to delete old %s", oldrefname);2681 goto rollback;2682 }26832684 /*2685 * Since we are doing a shallow lookup, sha1 is not the2686 * correct value to pass to delete_ref as old_sha1. But that2687 * doesn't matter, because an old_sha1 check wouldn't add to2688 * the safety anyway; we want to delete the reference whatever2689 * its current value.2690 */2691 if (!read_ref_full(newrefname, RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,2692 sha1, NULL) &&2693 delete_ref(newrefname, NULL, REF_NODEREF)) {2694 if (errno==EISDIR) {2695 struct strbuf path = STRBUF_INIT;2696 int result;26972698 strbuf_git_path(&path, "%s", newrefname);2699 result = remove_empty_directories(&path);2700 strbuf_release(&path);27012702 if (result) {2703 error("Directory not empty: %s", newrefname);2704 goto rollback;2705 }2706 } else {2707 error("unable to delete existing %s", newrefname);2708 goto rollback;2709 }2710 }27112712 if (log && rename_tmp_log(newrefname))2713 goto rollback;27142715 logmoved = log;27162717 lock = lock_ref_sha1_basic(newrefname, NULL, NULL, NULL, REF_NODEREF,2718 NULL, &err);2719 if (!lock) {2720 error("unable to rename '%s' to '%s': %s", oldrefname, newrefname, err.buf);2721 strbuf_release(&err);2722 goto rollback;2723 }2724 hashcpy(lock->old_oid.hash, orig_sha1);27252726 if (write_ref_to_lockfile(lock, orig_sha1, &err) ||2727 commit_ref_update(lock, orig_sha1, logmsg, &err)) {2728 error("unable to write current sha1 into %s: %s", newrefname, err.buf);2729 strbuf_release(&err);2730 goto rollback;2731 }27322733 return 0;27342735 rollback:2736 lock = lock_ref_sha1_basic(oldrefname, NULL, NULL, NULL, REF_NODEREF,2737 NULL, &err);2738 if (!lock) {2739 error("unable to lock %s for rollback: %s", oldrefname, err.buf);2740 strbuf_release(&err);2741 goto rollbacklog;2742 }27432744 flag = log_all_ref_updates;2745 log_all_ref_updates = 0;2746 if (write_ref_to_lockfile(lock, orig_sha1, &err) ||2747 commit_ref_update(lock, orig_sha1, NULL, &err)) {2748 error("unable to write current sha1 into %s: %s", oldrefname, err.buf);2749 strbuf_release(&err);2750 }2751 log_all_ref_updates = flag;27522753 rollbacklog:2754 if (logmoved && rename(git_path("logs/%s", newrefname), git_path("logs/%s", oldrefname)))2755 error("unable to restore logfile %s from %s: %s",2756 oldrefname, newrefname, strerror(errno));2757 if (!logmoved && log &&2758 rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", oldrefname)))2759 error("unable to restore logfile %s from "TMP_RENAMED_LOG": %s",2760 oldrefname, strerror(errno));27612762 return 1;2763}27642765static int close_ref(struct ref_lock *lock)2766{2767 if (close_lock_file(lock->lk))2768 return -1;2769 return 0;2770}27712772static int commit_ref(struct ref_lock *lock)2773{2774 char *path = get_locked_file_path(lock->lk);2775 struct stat st;27762777 if (!lstat(path, &st) && S_ISDIR(st.st_mode)) {2778 /*2779 * There is a directory at the path we want to rename2780 * the lockfile to. Hopefully it is empty; try to2781 * delete it.2782 */2783 size_t len = strlen(path);2784 struct strbuf sb_path = STRBUF_INIT;27852786 strbuf_attach(&sb_path, path, len, len);27872788 /*2789 * If this fails, commit_lock_file() will also fail2790 * and will report the problem.2791 */2792 remove_empty_directories(&sb_path);2793 strbuf_release(&sb_path);2794 } else {2795 free(path);2796 }27972798 if (commit_lock_file(lock->lk))2799 return -1;2800 return 0;2801}28022803/*2804 * Create a reflog for a ref. If force_create = 0, the reflog will2805 * only be created for certain refs (those for which2806 * should_autocreate_reflog returns non-zero. Otherwise, create it2807 * regardless of the ref name. Fill in *err and return -1 on failure.2808 */2809static int log_ref_setup(const char *refname, struct strbuf *logfile, struct strbuf *err, int force_create)2810{2811 int logfd, oflags = O_APPEND | O_WRONLY;28122813 strbuf_git_path(logfile, "logs/%s", refname);2814 if (force_create || should_autocreate_reflog(refname)) {2815 if (safe_create_leading_directories(logfile->buf) < 0) {2816 strbuf_addf(err, "unable to create directory for '%s': "2817 "%s", logfile->buf, strerror(errno));2818 return -1;2819 }2820 oflags |= O_CREAT;2821 }28222823 logfd = open(logfile->buf, oflags, 0666);2824 if (logfd < 0) {2825 if (!(oflags & O_CREAT) && (errno == ENOENT || errno == EISDIR))2826 return 0;28272828 if (errno == EISDIR) {2829 if (remove_empty_directories(logfile)) {2830 strbuf_addf(err, "there are still logs under "2831 "'%s'", logfile->buf);2832 return -1;2833 }2834 logfd = open(logfile->buf, oflags, 0666);2835 }28362837 if (logfd < 0) {2838 strbuf_addf(err, "unable to append to '%s': %s",2839 logfile->buf, strerror(errno));2840 return -1;2841 }2842 }28432844 adjust_shared_perm(logfile->buf);2845 close(logfd);2846 return 0;2847}284828492850int safe_create_reflog(const char *refname, int force_create, struct strbuf *err)2851{2852 int ret;2853 struct strbuf sb = STRBUF_INIT;28542855 ret = log_ref_setup(refname, &sb, err, force_create);2856 strbuf_release(&sb);2857 return ret;2858}28592860static int log_ref_write_fd(int fd, const unsigned char *old_sha1,2861 const unsigned char *new_sha1,2862 const char *committer, const char *msg)2863{2864 int msglen, written;2865 unsigned maxlen, len;2866 char *logrec;28672868 msglen = msg ? strlen(msg) : 0;2869 maxlen = strlen(committer) + msglen + 100;2870 logrec = xmalloc(maxlen);2871 len = xsnprintf(logrec, maxlen, "%s %s %s\n",2872 sha1_to_hex(old_sha1),2873 sha1_to_hex(new_sha1),2874 committer);2875 if (msglen)2876 len += copy_reflog_msg(logrec + len - 1, msg) - 1;28772878 written = len <= maxlen ? write_in_full(fd, logrec, len) : -1;2879 free(logrec);2880 if (written != len)2881 return -1;28822883 return 0;2884}28852886static int log_ref_write_1(const char *refname, const unsigned char *old_sha1,2887 const unsigned char *new_sha1, const char *msg,2888 struct strbuf *logfile, int flags,2889 struct strbuf *err)2890{2891 int logfd, result, oflags = O_APPEND | O_WRONLY;28922893 if (log_all_ref_updates < 0)2894 log_all_ref_updates = !is_bare_repository();28952896 result = log_ref_setup(refname, logfile, err, flags & REF_FORCE_CREATE_REFLOG);28972898 if (result)2899 return result;29002901 logfd = open(logfile->buf, oflags);2902 if (logfd < 0)2903 return 0;2904 result = log_ref_write_fd(logfd, old_sha1, new_sha1,2905 git_committer_info(0), msg);2906 if (result) {2907 strbuf_addf(err, "unable to append to '%s': %s", logfile->buf,2908 strerror(errno));2909 close(logfd);2910 return -1;2911 }2912 if (close(logfd)) {2913 strbuf_addf(err, "unable to append to '%s': %s", logfile->buf,2914 strerror(errno));2915 return -1;2916 }2917 return 0;2918}29192920static int log_ref_write(const char *refname, const unsigned char *old_sha1,2921 const unsigned char *new_sha1, const char *msg,2922 int flags, struct strbuf *err)2923{2924 return files_log_ref_write(refname, old_sha1, new_sha1, msg, flags,2925 err);2926}29272928int files_log_ref_write(const char *refname, const unsigned char *old_sha1,2929 const unsigned char *new_sha1, const char *msg,2930 int flags, struct strbuf *err)2931{2932 struct strbuf sb = STRBUF_INIT;2933 int ret = log_ref_write_1(refname, old_sha1, new_sha1, msg, &sb, flags,2934 err);2935 strbuf_release(&sb);2936 return ret;2937}29382939/*2940 * Write sha1 into the open lockfile, then close the lockfile. On2941 * errors, rollback the lockfile, fill in *err and2942 * return -1.2943 */2944static int write_ref_to_lockfile(struct ref_lock *lock,2945 const unsigned char *sha1, struct strbuf *err)2946{2947 static char term = '\n';2948 struct object *o;2949 int fd;29502951 o = parse_object(sha1);2952 if (!o) {2953 strbuf_addf(err,2954 "trying to write ref '%s' with nonexistent object %s",2955 lock->ref_name, sha1_to_hex(sha1));2956 unlock_ref(lock);2957 return -1;2958 }2959 if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {2960 strbuf_addf(err,2961 "trying to write non-commit object %s to branch '%s'",2962 sha1_to_hex(sha1), lock->ref_name);2963 unlock_ref(lock);2964 return -1;2965 }2966 fd = get_lock_file_fd(lock->lk);2967 if (write_in_full(fd, sha1_to_hex(sha1), 40) != 40 ||2968 write_in_full(fd, &term, 1) != 1 ||2969 close_ref(lock) < 0) {2970 strbuf_addf(err,2971 "couldn't write '%s'", get_lock_file_path(lock->lk));2972 unlock_ref(lock);2973 return -1;2974 }2975 return 0;2976}29772978/*2979 * Commit a change to a loose reference that has already been written2980 * to the loose reference lockfile. Also update the reflogs if2981 * necessary, using the specified lockmsg (which can be NULL).2982 */2983static int commit_ref_update(struct ref_lock *lock,2984 const unsigned char *sha1, const char *logmsg,2985 struct strbuf *err)2986{2987 struct files_ref_store *refs =2988 get_files_ref_store(NULL, "commit_ref_update");29892990 clear_loose_ref_cache(refs);2991 if (log_ref_write(lock->ref_name, lock->old_oid.hash, sha1, logmsg, 0, err)) {2992 char *old_msg = strbuf_detach(err, NULL);2993 strbuf_addf(err, "cannot update the ref '%s': %s",2994 lock->ref_name, old_msg);2995 free(old_msg);2996 unlock_ref(lock);2997 return -1;2998 }29993000 if (strcmp(lock->ref_name, "HEAD") != 0) {3001 /*3002 * Special hack: If a branch is updated directly and HEAD3003 * points to it (may happen on the remote side of a push3004 * for example) then logically the HEAD reflog should be3005 * updated too.3006 * A generic solution implies reverse symref information,3007 * but finding all symrefs pointing to the given branch3008 * would be rather costly for this rare event (the direct3009 * update of a branch) to be worth it. So let's cheat and3010 * check with HEAD only which should cover 99% of all usage3011 * scenarios (even 100% of the default ones).3012 */3013 unsigned char head_sha1[20];3014 int head_flag;3015 const char *head_ref;30163017 head_ref = resolve_ref_unsafe("HEAD", RESOLVE_REF_READING,3018 head_sha1, &head_flag);3019 if (head_ref && (head_flag & REF_ISSYMREF) &&3020 !strcmp(head_ref, lock->ref_name)) {3021 struct strbuf log_err = STRBUF_INIT;3022 if (log_ref_write("HEAD", lock->old_oid.hash, sha1,3023 logmsg, 0, &log_err)) {3024 error("%s", log_err.buf);3025 strbuf_release(&log_err);3026 }3027 }3028 }30293030 if (commit_ref(lock)) {3031 strbuf_addf(err, "couldn't set '%s'", lock->ref_name);3032 unlock_ref(lock);3033 return -1;3034 }30353036 unlock_ref(lock);3037 return 0;3038}30393040static int create_ref_symlink(struct ref_lock *lock, const char *target)3041{3042 int ret = -1;3043#ifndef NO_SYMLINK_HEAD3044 char *ref_path = get_locked_file_path(lock->lk);3045 unlink(ref_path);3046 ret = symlink(target, ref_path);3047 free(ref_path);30483049 if (ret)3050 fprintf(stderr, "no symlink - falling back to symbolic ref\n");3051#endif3052 return ret;3053}30543055static void update_symref_reflog(struct ref_lock *lock, const char *refname,3056 const char *target, const char *logmsg)3057{3058 struct strbuf err = STRBUF_INIT;3059 unsigned char new_sha1[20];3060 if (logmsg && !read_ref(target, new_sha1) &&3061 log_ref_write(refname, lock->old_oid.hash, new_sha1, logmsg, 0, &err)) {3062 error("%s", err.buf);3063 strbuf_release(&err);3064 }3065}30663067static int create_symref_locked(struct ref_lock *lock, const char *refname,3068 const char *target, const char *logmsg)3069{3070 if (prefer_symlink_refs && !create_ref_symlink(lock, target)) {3071 update_symref_reflog(lock, refname, target, logmsg);3072 return 0;3073 }30743075 if (!fdopen_lock_file(lock->lk, "w"))3076 return error("unable to fdopen %s: %s",3077 lock->lk->tempfile.filename.buf, strerror(errno));30783079 update_symref_reflog(lock, refname, target, logmsg);30803081 /* no error check; commit_ref will check ferror */3082 fprintf(lock->lk->tempfile.fp, "ref: %s\n", target);3083 if (commit_ref(lock) < 0)3084 return error("unable to write symref for %s: %s", refname,3085 strerror(errno));3086 return 0;3087}30883089int create_symref(const char *refname, const char *target, const char *logmsg)3090{3091 struct strbuf err = STRBUF_INIT;3092 struct ref_lock *lock;3093 int ret;30943095 lock = lock_ref_sha1_basic(refname, NULL, NULL, NULL, REF_NODEREF, NULL,3096 &err);3097 if (!lock) {3098 error("%s", err.buf);3099 strbuf_release(&err);3100 return -1;3101 }31023103 ret = create_symref_locked(lock, refname, target, logmsg);3104 unlock_ref(lock);3105 return ret;3106}31073108int set_worktree_head_symref(const char *gitdir, const char *target)3109{3110 static struct lock_file head_lock;3111 struct ref_lock *lock;3112 struct strbuf head_path = STRBUF_INIT;3113 const char *head_rel;3114 int ret;31153116 strbuf_addf(&head_path, "%s/HEAD", absolute_path(gitdir));3117 if (hold_lock_file_for_update(&head_lock, head_path.buf,3118 LOCK_NO_DEREF) < 0) {3119 struct strbuf err = STRBUF_INIT;3120 unable_to_lock_message(head_path.buf, errno, &err);3121 error("%s", err.buf);3122 strbuf_release(&err);3123 strbuf_release(&head_path);3124 return -1;3125 }31263127 /* head_rel will be "HEAD" for the main tree, "worktrees/wt/HEAD" for3128 linked trees */3129 head_rel = remove_leading_path(head_path.buf,3130 absolute_path(get_git_common_dir()));3131 /* to make use of create_symref_locked(), initialize ref_lock */3132 lock = xcalloc(1, sizeof(struct ref_lock));3133 lock->lk = &head_lock;3134 lock->ref_name = xstrdup(head_rel);31353136 ret = create_symref_locked(lock, head_rel, target, NULL);31373138 unlock_ref(lock); /* will free lock */3139 strbuf_release(&head_path);3140 return ret;3141}31423143int reflog_exists(const char *refname)3144{3145 struct stat st;31463147 return !lstat(git_path("logs/%s", refname), &st) &&3148 S_ISREG(st.st_mode);3149}31503151int delete_reflog(const char *refname)3152{3153 return remove_path(git_path("logs/%s", refname));3154}31553156static int show_one_reflog_ent(struct strbuf *sb, each_reflog_ent_fn fn, void *cb_data)3157{3158 unsigned char osha1[20], nsha1[20];3159 char *email_end, *message;3160 unsigned long timestamp;3161 int tz;31623163 /* old SP new SP name <email> SP time TAB msg LF */3164 if (sb->len < 83 || sb->buf[sb->len - 1] != '\n' ||3165 get_sha1_hex(sb->buf, osha1) || sb->buf[40] != ' ' ||3166 get_sha1_hex(sb->buf + 41, nsha1) || sb->buf[81] != ' ' ||3167 !(email_end = strchr(sb->buf + 82, '>')) ||3168 email_end[1] != ' ' ||3169 !(timestamp = strtoul(email_end + 2, &message, 10)) ||3170 !message || message[0] != ' ' ||3171 (message[1] != '+' && message[1] != '-') ||3172 !isdigit(message[2]) || !isdigit(message[3]) ||3173 !isdigit(message[4]) || !isdigit(message[5]))3174 return 0; /* corrupt? */3175 email_end[1] = '\0';3176 tz = strtol(message + 1, NULL, 10);3177 if (message[6] != '\t')3178 message += 6;3179 else3180 message += 7;3181 return fn(osha1, nsha1, sb->buf + 82, timestamp, tz, message, cb_data);3182}31833184static char *find_beginning_of_line(char *bob, char *scan)3185{3186 while (bob < scan && *(--scan) != '\n')3187 ; /* keep scanning backwards */3188 /*3189 * Return either beginning of the buffer, or LF at the end of3190 * the previous line.3191 */3192 return scan;3193}31943195int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn, void *cb_data)3196{3197 struct strbuf sb = STRBUF_INIT;3198 FILE *logfp;3199 long pos;3200 int ret = 0, at_tail = 1;32013202 logfp = fopen(git_path("logs/%s", refname), "r");3203 if (!logfp)3204 return -1;32053206 /* Jump to the end */3207 if (fseek(logfp, 0, SEEK_END) < 0)3208 return error("cannot seek back reflog for %s: %s",3209 refname, strerror(errno));3210 pos = ftell(logfp);3211 while (!ret && 0 < pos) {3212 int cnt;3213 size_t nread;3214 char buf[BUFSIZ];3215 char *endp, *scanp;32163217 /* Fill next block from the end */3218 cnt = (sizeof(buf) < pos) ? sizeof(buf) : pos;3219 if (fseek(logfp, pos - cnt, SEEK_SET))3220 return error("cannot seek back reflog for %s: %s",3221 refname, strerror(errno));3222 nread = fread(buf, cnt, 1, logfp);3223 if (nread != 1)3224 return error("cannot read %d bytes from reflog for %s: %s",3225 cnt, refname, strerror(errno));3226 pos -= cnt;32273228 scanp = endp = buf + cnt;3229 if (at_tail && scanp[-1] == '\n')3230 /* Looking at the final LF at the end of the file */3231 scanp--;3232 at_tail = 0;32333234 while (buf < scanp) {3235 /*3236 * terminating LF of the previous line, or the beginning3237 * of the buffer.3238 */3239 char *bp;32403241 bp = find_beginning_of_line(buf, scanp);32423243 if (*bp == '\n') {3244 /*3245 * The newline is the end of the previous line,3246 * so we know we have complete line starting3247 * at (bp + 1). Prefix it onto any prior data3248 * we collected for the line and process it.3249 */3250 strbuf_splice(&sb, 0, 0, bp + 1, endp - (bp + 1));3251 scanp = bp;3252 endp = bp + 1;3253 ret = show_one_reflog_ent(&sb, fn, cb_data);3254 strbuf_reset(&sb);3255 if (ret)3256 break;3257 } else if (!pos) {3258 /*3259 * We are at the start of the buffer, and the3260 * start of the file; there is no previous3261 * line, and we have everything for this one.3262 * Process it, and we can end the loop.3263 */3264 strbuf_splice(&sb, 0, 0, buf, endp - buf);3265 ret = show_one_reflog_ent(&sb, fn, cb_data);3266 strbuf_reset(&sb);3267 break;3268 }32693270 if (bp == buf) {3271 /*3272 * We are at the start of the buffer, and there3273 * is more file to read backwards. Which means3274 * we are in the middle of a line. Note that we3275 * may get here even if *bp was a newline; that3276 * just means we are at the exact end of the3277 * previous line, rather than some spot in the3278 * middle.3279 *3280 * Save away what we have to be combined with3281 * the data from the next read.3282 */3283 strbuf_splice(&sb, 0, 0, buf, endp - buf);3284 break;3285 }3286 }32873288 }3289 if (!ret && sb.len)3290 die("BUG: reverse reflog parser had leftover data");32913292 fclose(logfp);3293 strbuf_release(&sb);3294 return ret;3295}32963297int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn, void *cb_data)3298{3299 FILE *logfp;3300 struct strbuf sb = STRBUF_INIT;3301 int ret = 0;33023303 logfp = fopen(git_path("logs/%s", refname), "r");3304 if (!logfp)3305 return -1;33063307 while (!ret && !strbuf_getwholeline(&sb, logfp, '\n'))3308 ret = show_one_reflog_ent(&sb, fn, cb_data);3309 fclose(logfp);3310 strbuf_release(&sb);3311 return ret;3312}33133314struct files_reflog_iterator {3315 struct ref_iterator base;33163317 struct dir_iterator *dir_iterator;3318 struct object_id oid;3319};33203321static int files_reflog_iterator_advance(struct ref_iterator *ref_iterator)3322{3323 struct files_reflog_iterator *iter =3324 (struct files_reflog_iterator *)ref_iterator;3325 struct dir_iterator *diter = iter->dir_iterator;3326 int ok;33273328 while ((ok = dir_iterator_advance(diter)) == ITER_OK) {3329 int flags;33303331 if (!S_ISREG(diter->st.st_mode))3332 continue;3333 if (diter->basename[0] == '.')3334 continue;3335 if (ends_with(diter->basename, ".lock"))3336 continue;33373338 if (read_ref_full(diter->relative_path, 0,3339 iter->oid.hash, &flags)) {3340 error("bad ref for %s", diter->path.buf);3341 continue;3342 }33433344 iter->base.refname = diter->relative_path;3345 iter->base.oid = &iter->oid;3346 iter->base.flags = flags;3347 return ITER_OK;3348 }33493350 iter->dir_iterator = NULL;3351 if (ref_iterator_abort(ref_iterator) == ITER_ERROR)3352 ok = ITER_ERROR;3353 return ok;3354}33553356static int files_reflog_iterator_peel(struct ref_iterator *ref_iterator,3357 struct object_id *peeled)3358{3359 die("BUG: ref_iterator_peel() called for reflog_iterator");3360}33613362static int files_reflog_iterator_abort(struct ref_iterator *ref_iterator)3363{3364 struct files_reflog_iterator *iter =3365 (struct files_reflog_iterator *)ref_iterator;3366 int ok = ITER_DONE;33673368 if (iter->dir_iterator)3369 ok = dir_iterator_abort(iter->dir_iterator);33703371 base_ref_iterator_free(ref_iterator);3372 return ok;3373}33743375static struct ref_iterator_vtable files_reflog_iterator_vtable = {3376 files_reflog_iterator_advance,3377 files_reflog_iterator_peel,3378 files_reflog_iterator_abort3379};33803381struct ref_iterator *files_reflog_iterator_begin(void)3382{3383 struct files_reflog_iterator *iter = xcalloc(1, sizeof(*iter));3384 struct ref_iterator *ref_iterator = &iter->base;33853386 base_ref_iterator_init(ref_iterator, &files_reflog_iterator_vtable);3387 iter->dir_iterator = dir_iterator_begin(git_path("logs"));3388 return ref_iterator;3389}33903391int for_each_reflog(each_ref_fn fn, void *cb_data)3392{3393 return do_for_each_ref_iterator(files_reflog_iterator_begin(),3394 fn, cb_data);3395}33963397static int ref_update_reject_duplicates(struct string_list *refnames,3398 struct strbuf *err)3399{3400 int i, n = refnames->nr;34013402 assert(err);34033404 for (i = 1; i < n; i++)3405 if (!strcmp(refnames->items[i - 1].string, refnames->items[i].string)) {3406 strbuf_addf(err,3407 "multiple updates for ref '%s' not allowed.",3408 refnames->items[i].string);3409 return 1;3410 }3411 return 0;3412}34133414/*3415 * If update is a direct update of head_ref (the reference pointed to3416 * by HEAD), then add an extra REF_LOG_ONLY update for HEAD.3417 */3418static int split_head_update(struct ref_update *update,3419 struct ref_transaction *transaction,3420 const char *head_ref,3421 struct string_list *affected_refnames,3422 struct strbuf *err)3423{3424 struct string_list_item *item;3425 struct ref_update *new_update;34263427 if ((update->flags & REF_LOG_ONLY) ||3428 (update->flags & REF_ISPRUNING) ||3429 (update->flags & REF_UPDATE_VIA_HEAD))3430 return 0;34313432 if (strcmp(update->refname, head_ref))3433 return 0;34343435 /*3436 * First make sure that HEAD is not already in the3437 * transaction. This insertion is O(N) in the transaction3438 * size, but it happens at most once per transaction.3439 */3440 item = string_list_insert(affected_refnames, "HEAD");3441 if (item->util) {3442 /* An entry already existed */3443 strbuf_addf(err,3444 "multiple updates for 'HEAD' (including one "3445 "via its referent '%s') are not allowed",3446 update->refname);3447 return TRANSACTION_NAME_CONFLICT;3448 }34493450 new_update = ref_transaction_add_update(3451 transaction, "HEAD",3452 update->flags | REF_LOG_ONLY | REF_NODEREF,3453 update->new_sha1, update->old_sha1,3454 update->msg);34553456 item->util = new_update;34573458 return 0;3459}34603461/*3462 * update is for a symref that points at referent and doesn't have3463 * REF_NODEREF set. Split it into two updates:3464 * - The original update, but with REF_LOG_ONLY and REF_NODEREF set3465 * - A new, separate update for the referent reference3466 * Note that the new update will itself be subject to splitting when3467 * the iteration gets to it.3468 */3469static int split_symref_update(struct ref_update *update,3470 const char *referent,3471 struct ref_transaction *transaction,3472 struct string_list *affected_refnames,3473 struct strbuf *err)3474{3475 struct string_list_item *item;3476 struct ref_update *new_update;3477 unsigned int new_flags;34783479 /*3480 * First make sure that referent is not already in the3481 * transaction. This insertion is O(N) in the transaction3482 * size, but it happens at most once per symref in a3483 * transaction.3484 */3485 item = string_list_insert(affected_refnames, referent);3486 if (item->util) {3487 /* An entry already existed */3488 strbuf_addf(err,3489 "multiple updates for '%s' (including one "3490 "via symref '%s') are not allowed",3491 referent, update->refname);3492 return TRANSACTION_NAME_CONFLICT;3493 }34943495 new_flags = update->flags;3496 if (!strcmp(update->refname, "HEAD")) {3497 /*3498 * Record that the new update came via HEAD, so that3499 * when we process it, split_head_update() doesn't try3500 * to add another reflog update for HEAD. Note that3501 * this bit will be propagated if the new_update3502 * itself needs to be split.3503 */3504 new_flags |= REF_UPDATE_VIA_HEAD;3505 }35063507 new_update = ref_transaction_add_update(3508 transaction, referent, new_flags,3509 update->new_sha1, update->old_sha1,3510 update->msg);35113512 new_update->parent_update = update;35133514 /*3515 * Change the symbolic ref update to log only. Also, it3516 * doesn't need to check its old SHA-1 value, as that will be3517 * done when new_update is processed.3518 */3519 update->flags |= REF_LOG_ONLY | REF_NODEREF;3520 update->flags &= ~REF_HAVE_OLD;35213522 item->util = new_update;35233524 return 0;3525}35263527/*3528 * Return the refname under which update was originally requested.3529 */3530static const char *original_update_refname(struct ref_update *update)3531{3532 while (update->parent_update)3533 update = update->parent_update;35343535 return update->refname;3536}35373538/*3539 * Prepare for carrying out update:3540 * - Lock the reference referred to by update.3541 * - Read the reference under lock.3542 * - Check that its old SHA-1 value (if specified) is correct, and in3543 * any case record it in update->lock->old_oid for later use when3544 * writing the reflog.3545 * - If it is a symref update without REF_NODEREF, split it up into a3546 * REF_LOG_ONLY update of the symref and add a separate update for3547 * the referent to transaction.3548 * - If it is an update of head_ref, add a corresponding REF_LOG_ONLY3549 * update of HEAD.3550 */3551static int lock_ref_for_update(struct ref_update *update,3552 struct ref_transaction *transaction,3553 const char *head_ref,3554 struct string_list *affected_refnames,3555 struct strbuf *err)3556{3557 struct strbuf referent = STRBUF_INIT;3558 int mustexist = (update->flags & REF_HAVE_OLD) &&3559 !is_null_sha1(update->old_sha1);3560 int ret;3561 struct ref_lock *lock;35623563 if ((update->flags & REF_HAVE_NEW) && is_null_sha1(update->new_sha1))3564 update->flags |= REF_DELETING;35653566 if (head_ref) {3567 ret = split_head_update(update, transaction, head_ref,3568 affected_refnames, err);3569 if (ret)3570 return ret;3571 }35723573 ret = lock_raw_ref(update->refname, mustexist,3574 affected_refnames, NULL,3575 &update->lock, &referent,3576 &update->type, err);35773578 if (ret) {3579 char *reason;35803581 reason = strbuf_detach(err, NULL);3582 strbuf_addf(err, "cannot lock ref '%s': %s",3583 update->refname, reason);3584 free(reason);3585 return ret;3586 }35873588 lock = update->lock;35893590 if (update->type & REF_ISSYMREF) {3591 if (update->flags & REF_NODEREF) {3592 /*3593 * We won't be reading the referent as part of3594 * the transaction, so we have to read it here3595 * to record and possibly check old_sha1:3596 */3597 if (read_ref_full(update->refname,3598 mustexist ? RESOLVE_REF_READING : 0,3599 lock->old_oid.hash, NULL)) {3600 if (update->flags & REF_HAVE_OLD) {3601 strbuf_addf(err, "cannot lock ref '%s': "3602 "can't resolve old value",3603 update->refname);3604 return TRANSACTION_GENERIC_ERROR;3605 } else {3606 hashclr(lock->old_oid.hash);3607 }3608 }3609 if ((update->flags & REF_HAVE_OLD) &&3610 hashcmp(lock->old_oid.hash, update->old_sha1)) {3611 strbuf_addf(err, "cannot lock ref '%s': "3612 "is at %s but expected %s",3613 update->refname,3614 sha1_to_hex(lock->old_oid.hash),3615 sha1_to_hex(update->old_sha1));3616 return TRANSACTION_GENERIC_ERROR;3617 }36183619 } else {3620 /*3621 * Create a new update for the reference this3622 * symref is pointing at. Also, we will record3623 * and verify old_sha1 for this update as part3624 * of processing the split-off update, so we3625 * don't have to do it here.3626 */3627 ret = split_symref_update(update, referent.buf, transaction,3628 affected_refnames, err);3629 if (ret)3630 return ret;3631 }3632 } else {3633 struct ref_update *parent_update;36343635 /*3636 * If this update is happening indirectly because of a3637 * symref update, record the old SHA-1 in the parent3638 * update:3639 */3640 for (parent_update = update->parent_update;3641 parent_update;3642 parent_update = parent_update->parent_update) {3643 oidcpy(&parent_update->lock->old_oid, &lock->old_oid);3644 }36453646 if ((update->flags & REF_HAVE_OLD) &&3647 hashcmp(lock->old_oid.hash, update->old_sha1)) {3648 if (is_null_sha1(update->old_sha1))3649 strbuf_addf(err, "cannot lock ref '%s': reference already exists",3650 original_update_refname(update));3651 else3652 strbuf_addf(err, "cannot lock ref '%s': is at %s but expected %s",3653 original_update_refname(update),3654 sha1_to_hex(lock->old_oid.hash),3655 sha1_to_hex(update->old_sha1));36563657 return TRANSACTION_GENERIC_ERROR;3658 }3659 }36603661 if ((update->flags & REF_HAVE_NEW) &&3662 !(update->flags & REF_DELETING) &&3663 !(update->flags & REF_LOG_ONLY)) {3664 if (!(update->type & REF_ISSYMREF) &&3665 !hashcmp(lock->old_oid.hash, update->new_sha1)) {3666 /*3667 * The reference already has the desired3668 * value, so we don't need to write it.3669 */3670 } else if (write_ref_to_lockfile(lock, update->new_sha1,3671 err)) {3672 char *write_err = strbuf_detach(err, NULL);36733674 /*3675 * The lock was freed upon failure of3676 * write_ref_to_lockfile():3677 */3678 update->lock = NULL;3679 strbuf_addf(err,3680 "cannot update the ref '%s': %s",3681 update->refname, write_err);3682 free(write_err);3683 return TRANSACTION_GENERIC_ERROR;3684 } else {3685 update->flags |= REF_NEEDS_COMMIT;3686 }3687 }3688 if (!(update->flags & REF_NEEDS_COMMIT)) {3689 /*3690 * We didn't call write_ref_to_lockfile(), so3691 * the lockfile is still open. Close it to3692 * free up the file descriptor:3693 */3694 if (close_ref(lock)) {3695 strbuf_addf(err, "couldn't close '%s.lock'",3696 update->refname);3697 return TRANSACTION_GENERIC_ERROR;3698 }3699 }3700 return 0;3701}37023703int ref_transaction_commit(struct ref_transaction *transaction,3704 struct strbuf *err)3705{3706 struct files_ref_store *refs =3707 get_files_ref_store(NULL, "ref_transaction_commit");3708 int ret = 0, i;3709 struct string_list refs_to_delete = STRING_LIST_INIT_NODUP;3710 struct string_list_item *ref_to_delete;3711 struct string_list affected_refnames = STRING_LIST_INIT_NODUP;3712 char *head_ref = NULL;3713 int head_type;3714 struct object_id head_oid;37153716 assert(err);37173718 if (transaction->state != REF_TRANSACTION_OPEN)3719 die("BUG: commit called for transaction that is not open");37203721 if (!transaction->nr) {3722 transaction->state = REF_TRANSACTION_CLOSED;3723 return 0;3724 }37253726 /*3727 * Fail if a refname appears more than once in the3728 * transaction. (If we end up splitting up any updates using3729 * split_symref_update() or split_head_update(), those3730 * functions will check that the new updates don't have the3731 * same refname as any existing ones.)3732 */3733 for (i = 0; i < transaction->nr; i++) {3734 struct ref_update *update = transaction->updates[i];3735 struct string_list_item *item =3736 string_list_append(&affected_refnames, update->refname);37373738 /*3739 * We store a pointer to update in item->util, but at3740 * the moment we never use the value of this field3741 * except to check whether it is non-NULL.3742 */3743 item->util = update;3744 }3745 string_list_sort(&affected_refnames);3746 if (ref_update_reject_duplicates(&affected_refnames, err)) {3747 ret = TRANSACTION_GENERIC_ERROR;3748 goto cleanup;3749 }37503751 /*3752 * Special hack: If a branch is updated directly and HEAD3753 * points to it (may happen on the remote side of a push3754 * for example) then logically the HEAD reflog should be3755 * updated too.3756 *3757 * A generic solution would require reverse symref lookups,3758 * but finding all symrefs pointing to a given branch would be3759 * rather costly for this rare event (the direct update of a3760 * branch) to be worth it. So let's cheat and check with HEAD3761 * only, which should cover 99% of all usage scenarios (even3762 * 100% of the default ones).3763 *3764 * So if HEAD is a symbolic reference, then record the name of3765 * the reference that it points to. If we see an update of3766 * head_ref within the transaction, then split_head_update()3767 * arranges for the reflog of HEAD to be updated, too.3768 */3769 head_ref = resolve_refdup("HEAD", RESOLVE_REF_NO_RECURSE,3770 head_oid.hash, &head_type);37713772 if (head_ref && !(head_type & REF_ISSYMREF)) {3773 free(head_ref);3774 head_ref = NULL;3775 }37763777 /*3778 * Acquire all locks, verify old values if provided, check3779 * that new values are valid, and write new values to the3780 * lockfiles, ready to be activated. Only keep one lockfile3781 * open at a time to avoid running out of file descriptors.3782 */3783 for (i = 0; i < transaction->nr; i++) {3784 struct ref_update *update = transaction->updates[i];37853786 ret = lock_ref_for_update(update, transaction, head_ref,3787 &affected_refnames, err);3788 if (ret)3789 goto cleanup;3790 }37913792 /* Perform updates first so live commits remain referenced */3793 for (i = 0; i < transaction->nr; i++) {3794 struct ref_update *update = transaction->updates[i];3795 struct ref_lock *lock = update->lock;37963797 if (update->flags & REF_NEEDS_COMMIT ||3798 update->flags & REF_LOG_ONLY) {3799 if (log_ref_write(lock->ref_name, lock->old_oid.hash,3800 update->new_sha1,3801 update->msg, update->flags, err)) {3802 char *old_msg = strbuf_detach(err, NULL);38033804 strbuf_addf(err, "cannot update the ref '%s': %s",3805 lock->ref_name, old_msg);3806 free(old_msg);3807 unlock_ref(lock);3808 update->lock = NULL;3809 ret = TRANSACTION_GENERIC_ERROR;3810 goto cleanup;3811 }3812 }3813 if (update->flags & REF_NEEDS_COMMIT) {3814 clear_loose_ref_cache(refs);3815 if (commit_ref(lock)) {3816 strbuf_addf(err, "couldn't set '%s'", lock->ref_name);3817 unlock_ref(lock);3818 update->lock = NULL;3819 ret = TRANSACTION_GENERIC_ERROR;3820 goto cleanup;3821 }3822 }3823 }3824 /* Perform deletes now that updates are safely completed */3825 for (i = 0; i < transaction->nr; i++) {3826 struct ref_update *update = transaction->updates[i];38273828 if (update->flags & REF_DELETING &&3829 !(update->flags & REF_LOG_ONLY)) {3830 if (delete_ref_loose(update->lock, update->type, err)) {3831 ret = TRANSACTION_GENERIC_ERROR;3832 goto cleanup;3833 }38343835 if (!(update->flags & REF_ISPRUNING))3836 string_list_append(&refs_to_delete,3837 update->lock->ref_name);3838 }3839 }38403841 if (repack_without_refs(&refs_to_delete, err)) {3842 ret = TRANSACTION_GENERIC_ERROR;3843 goto cleanup;3844 }3845 for_each_string_list_item(ref_to_delete, &refs_to_delete)3846 unlink_or_warn(git_path("logs/%s", ref_to_delete->string));3847 clear_loose_ref_cache(refs);38483849cleanup:3850 transaction->state = REF_TRANSACTION_CLOSED;38513852 for (i = 0; i < transaction->nr; i++)3853 if (transaction->updates[i]->lock)3854 unlock_ref(transaction->updates[i]->lock);3855 string_list_clear(&refs_to_delete, 0);3856 free(head_ref);3857 string_list_clear(&affected_refnames, 0);38583859 return ret;3860}38613862static int ref_present(const char *refname,3863 const struct object_id *oid, int flags, void *cb_data)3864{3865 struct string_list *affected_refnames = cb_data;38663867 return string_list_has_string(affected_refnames, refname);3868}38693870int initial_ref_transaction_commit(struct ref_transaction *transaction,3871 struct strbuf *err)3872{3873 struct files_ref_store *refs =3874 get_files_ref_store(NULL, "initial_ref_transaction_commit");3875 int ret = 0, i;3876 struct string_list affected_refnames = STRING_LIST_INIT_NODUP;38773878 assert(err);38793880 if (transaction->state != REF_TRANSACTION_OPEN)3881 die("BUG: commit called for transaction that is not open");38823883 /* Fail if a refname appears more than once in the transaction: */3884 for (i = 0; i < transaction->nr; i++)3885 string_list_append(&affected_refnames,3886 transaction->updates[i]->refname);3887 string_list_sort(&affected_refnames);3888 if (ref_update_reject_duplicates(&affected_refnames, err)) {3889 ret = TRANSACTION_GENERIC_ERROR;3890 goto cleanup;3891 }38923893 /*3894 * It's really undefined to call this function in an active3895 * repository or when there are existing references: we are3896 * only locking and changing packed-refs, so (1) any3897 * simultaneous processes might try to change a reference at3898 * the same time we do, and (2) any existing loose versions of3899 * the references that we are setting would have precedence3900 * over our values. But some remote helpers create the remote3901 * "HEAD" and "master" branches before calling this function,3902 * so here we really only check that none of the references3903 * that we are creating already exists.3904 */3905 if (for_each_rawref(ref_present, &affected_refnames))3906 die("BUG: initial ref transaction called with existing refs");39073908 for (i = 0; i < transaction->nr; i++) {3909 struct ref_update *update = transaction->updates[i];39103911 if ((update->flags & REF_HAVE_OLD) &&3912 !is_null_sha1(update->old_sha1))3913 die("BUG: initial ref transaction with old_sha1 set");3914 if (verify_refname_available(update->refname,3915 &affected_refnames, NULL,3916 err)) {3917 ret = TRANSACTION_NAME_CONFLICT;3918 goto cleanup;3919 }3920 }39213922 if (lock_packed_refs(0)) {3923 strbuf_addf(err, "unable to lock packed-refs file: %s",3924 strerror(errno));3925 ret = TRANSACTION_GENERIC_ERROR;3926 goto cleanup;3927 }39283929 for (i = 0; i < transaction->nr; i++) {3930 struct ref_update *update = transaction->updates[i];39313932 if ((update->flags & REF_HAVE_NEW) &&3933 !is_null_sha1(update->new_sha1))3934 add_packed_ref(refs, update->refname, update->new_sha1);3935 }39363937 if (commit_packed_refs()) {3938 strbuf_addf(err, "unable to commit packed-refs file: %s",3939 strerror(errno));3940 ret = TRANSACTION_GENERIC_ERROR;3941 goto cleanup;3942 }39433944cleanup:3945 transaction->state = REF_TRANSACTION_CLOSED;3946 string_list_clear(&affected_refnames, 0);3947 return ret;3948}39493950struct expire_reflog_cb {3951 unsigned int flags;3952 reflog_expiry_should_prune_fn *should_prune_fn;3953 void *policy_cb;3954 FILE *newlog;3955 unsigned char last_kept_sha1[20];3956};39573958static int expire_reflog_ent(unsigned char *osha1, unsigned char *nsha1,3959 const char *email, unsigned long timestamp, int tz,3960 const char *message, void *cb_data)3961{3962 struct expire_reflog_cb *cb = cb_data;3963 struct expire_reflog_policy_cb *policy_cb = cb->policy_cb;39643965 if (cb->flags & EXPIRE_REFLOGS_REWRITE)3966 osha1 = cb->last_kept_sha1;39673968 if ((*cb->should_prune_fn)(osha1, nsha1, email, timestamp, tz,3969 message, policy_cb)) {3970 if (!cb->newlog)3971 printf("would prune %s", message);3972 else if (cb->flags & EXPIRE_REFLOGS_VERBOSE)3973 printf("prune %s", message);3974 } else {3975 if (cb->newlog) {3976 fprintf(cb->newlog, "%s %s %s %lu %+05d\t%s",3977 sha1_to_hex(osha1), sha1_to_hex(nsha1),3978 email, timestamp, tz, message);3979 hashcpy(cb->last_kept_sha1, nsha1);3980 }3981 if (cb->flags & EXPIRE_REFLOGS_VERBOSE)3982 printf("keep %s", message);3983 }3984 return 0;3985}39863987int reflog_expire(const char *refname, const unsigned char *sha1,3988 unsigned int flags,3989 reflog_expiry_prepare_fn prepare_fn,3990 reflog_expiry_should_prune_fn should_prune_fn,3991 reflog_expiry_cleanup_fn cleanup_fn,3992 void *policy_cb_data)3993{3994 static struct lock_file reflog_lock;3995 struct expire_reflog_cb cb;3996 struct ref_lock *lock;3997 char *log_file;3998 int status = 0;3999 int type;4000 struct strbuf err = STRBUF_INIT;40014002 memset(&cb, 0, sizeof(cb));4003 cb.flags = flags;4004 cb.policy_cb = policy_cb_data;4005 cb.should_prune_fn = should_prune_fn;40064007 /*4008 * The reflog file is locked by holding the lock on the4009 * reference itself, plus we might need to update the4010 * reference if --updateref was specified:4011 */4012 lock = lock_ref_sha1_basic(refname, sha1, NULL, NULL, REF_NODEREF,4013 &type, &err);4014 if (!lock) {4015 error("cannot lock ref '%s': %s", refname, err.buf);4016 strbuf_release(&err);4017 return -1;4018 }4019 if (!reflog_exists(refname)) {4020 unlock_ref(lock);4021 return 0;4022 }40234024 log_file = git_pathdup("logs/%s", refname);4025 if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {4026 /*4027 * Even though holding $GIT_DIR/logs/$reflog.lock has4028 * no locking implications, we use the lock_file4029 * machinery here anyway because it does a lot of the4030 * work we need, including cleaning up if the program4031 * exits unexpectedly.4032 */4033 if (hold_lock_file_for_update(&reflog_lock, log_file, 0) < 0) {4034 struct strbuf err = STRBUF_INIT;4035 unable_to_lock_message(log_file, errno, &err);4036 error("%s", err.buf);4037 strbuf_release(&err);4038 goto failure;4039 }4040 cb.newlog = fdopen_lock_file(&reflog_lock, "w");4041 if (!cb.newlog) {4042 error("cannot fdopen %s (%s)",4043 get_lock_file_path(&reflog_lock), strerror(errno));4044 goto failure;4045 }4046 }40474048 (*prepare_fn)(refname, sha1, cb.policy_cb);4049 for_each_reflog_ent(refname, expire_reflog_ent, &cb);4050 (*cleanup_fn)(cb.policy_cb);40514052 if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {4053 /*4054 * It doesn't make sense to adjust a reference pointed4055 * to by a symbolic ref based on expiring entries in4056 * the symbolic reference's reflog. Nor can we update4057 * a reference if there are no remaining reflog4058 * entries.4059 */4060 int update = (flags & EXPIRE_REFLOGS_UPDATE_REF) &&4061 !(type & REF_ISSYMREF) &&4062 !is_null_sha1(cb.last_kept_sha1);40634064 if (close_lock_file(&reflog_lock)) {4065 status |= error("couldn't write %s: %s", log_file,4066 strerror(errno));4067 } else if (update &&4068 (write_in_full(get_lock_file_fd(lock->lk),4069 sha1_to_hex(cb.last_kept_sha1), 40) != 40 ||4070 write_str_in_full(get_lock_file_fd(lock->lk), "\n") != 1 ||4071 close_ref(lock) < 0)) {4072 status |= error("couldn't write %s",4073 get_lock_file_path(lock->lk));4074 rollback_lock_file(&reflog_lock);4075 } else if (commit_lock_file(&reflog_lock)) {4076 status |= error("unable to write reflog '%s' (%s)",4077 log_file, strerror(errno));4078 } else if (update && commit_ref(lock)) {4079 status |= error("couldn't set %s", lock->ref_name);4080 }4081 }4082 free(log_file);4083 unlock_ref(lock);4084 return status;40854086 failure:4087 rollback_lock_file(&reflog_lock);4088 free(log_file);4089 unlock_ref(lock);4090 return -1;4091}40924093struct ref_storage_be refs_be_files = {4094 NULL,4095 "files",4096 files_ref_store_create4097};