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, 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; 915 916 /* 917 * The name of the submodule represented by this object, or 918 * the empty string if it represents the main repository's 919 * reference store: 920 */ 921 const char *submodule; 922 923 struct ref_entry *loose; 924 struct packed_ref_cache *packed; 925}; 926 927/* Lock used for the main packed-refs file: */ 928static struct lock_file packlock; 929 930/* 931 * Increment the reference count of *packed_refs. 932 */ 933static void acquire_packed_ref_cache(struct packed_ref_cache *packed_refs) 934{ 935 packed_refs->referrers++; 936} 937 938/* 939 * Decrease the reference count of *packed_refs. If it goes to zero, 940 * free *packed_refs and return true; otherwise return false. 941 */ 942static int release_packed_ref_cache(struct packed_ref_cache *packed_refs) 943{ 944 if (!--packed_refs->referrers) { 945 free_ref_entry(packed_refs->root); 946 stat_validity_clear(&packed_refs->validity); 947 free(packed_refs); 948 return 1; 949 } else { 950 return 0; 951 } 952} 953 954static void clear_packed_ref_cache(struct files_ref_store *refs) 955{ 956 if (refs->packed) { 957 struct packed_ref_cache *packed_refs = refs->packed; 958 959 if (packed_refs->lock) 960 die("internal error: packed-ref cache cleared while locked"); 961 refs->packed = NULL; 962 release_packed_ref_cache(packed_refs); 963 } 964} 965 966static void clear_loose_ref_cache(struct files_ref_store *refs) 967{ 968 if (refs->loose) { 969 free_ref_entry(refs->loose); 970 refs->loose = NULL; 971 } 972} 973 974/* 975 * Create a new submodule ref cache and add it to the internal 976 * set of caches. 977 */ 978static struct ref_store *files_ref_store_create(const char *submodule) 979{ 980 struct files_ref_store *refs = xcalloc(1, sizeof(*refs)); 981 struct ref_store *ref_store = (struct ref_store *)refs; 982 983 base_ref_store_init(ref_store, &refs_be_files); 984 985 refs->submodule = submodule ? xstrdup(submodule) : ""; 986 987 return ref_store; 988} 989 990/* 991 * Die if refs is for a submodule (i.e., not for the main repository). 992 * caller is used in any necessary error messages. 993 */ 994static void files_assert_main_repository(struct files_ref_store *refs, 995 const char *caller) 996{ 997 if (*refs->submodule) 998 die("BUG: %s called for a submodule", caller); 999}10001001/*1002 * Downcast ref_store to files_ref_store. Die if ref_store is not a1003 * files_ref_store. If submodule_allowed is not true, then also die if1004 * files_ref_store is for a submodule (i.e., not for the main1005 * repository). caller is used in any necessary error messages.1006 */1007static struct files_ref_store *files_downcast(1008 struct ref_store *ref_store, int submodule_allowed,1009 const char *caller)1010{1011 struct files_ref_store *refs;10121013 if (ref_store->be != &refs_be_files)1014 die("BUG: ref_store is type \"%s\" not \"files\" in %s",1015 ref_store->be->name, caller);10161017 refs = (struct files_ref_store *)ref_store;10181019 if (!submodule_allowed)1020 files_assert_main_repository(refs, caller);10211022 return refs;1023}10241025/* The length of a peeled reference line in packed-refs, including EOL: */1026#define PEELED_LINE_LENGTH 4210271028/*1029 * The packed-refs header line that we write out. Perhaps other1030 * traits will be added later. The trailing space is required.1031 */1032static const char PACKED_REFS_HEADER[] =1033 "# pack-refs with: peeled fully-peeled \n";10341035/*1036 * Parse one line from a packed-refs file. Write the SHA1 to sha1.1037 * Return a pointer to the refname within the line (null-terminated),1038 * or NULL if there was a problem.1039 */1040static const char *parse_ref_line(struct strbuf *line, unsigned char *sha1)1041{1042 const char *ref;10431044 /*1045 * 42: the answer to everything.1046 *1047 * In this case, it happens to be the answer to1048 * 40 (length of sha1 hex representation)1049 * +1 (space in between hex and name)1050 * +1 (newline at the end of the line)1051 */1052 if (line->len <= 42)1053 return NULL;10541055 if (get_sha1_hex(line->buf, sha1) < 0)1056 return NULL;1057 if (!isspace(line->buf[40]))1058 return NULL;10591060 ref = line->buf + 41;1061 if (isspace(*ref))1062 return NULL;10631064 if (line->buf[line->len - 1] != '\n')1065 return NULL;1066 line->buf[--line->len] = 0;10671068 return ref;1069}10701071/*1072 * Read f, which is a packed-refs file, into dir.1073 *1074 * A comment line of the form "# pack-refs with: " may contain zero or1075 * more traits. We interpret the traits as follows:1076 *1077 * No traits:1078 *1079 * Probably no references are peeled. But if the file contains a1080 * peeled value for a reference, we will use it.1081 *1082 * peeled:1083 *1084 * References under "refs/tags/", if they *can* be peeled, *are*1085 * peeled in this file. References outside of "refs/tags/" are1086 * probably not peeled even if they could have been, but if we find1087 * a peeled value for such a reference we will use it.1088 *1089 * fully-peeled:1090 *1091 * All references in the file that can be peeled are peeled.1092 * Inversely (and this is more important), any references in the1093 * file for which no peeled value is recorded is not peelable. This1094 * trait should typically be written alongside "peeled" for1095 * compatibility with older clients, but we do not require it1096 * (i.e., "peeled" is a no-op if "fully-peeled" is set).1097 */1098static void read_packed_refs(FILE *f, struct ref_dir *dir)1099{1100 struct ref_entry *last = NULL;1101 struct strbuf line = STRBUF_INIT;1102 enum { PEELED_NONE, PEELED_TAGS, PEELED_FULLY } peeled = PEELED_NONE;11031104 while (strbuf_getwholeline(&line, f, '\n') != EOF) {1105 unsigned char sha1[20];1106 const char *refname;1107 const char *traits;11081109 if (skip_prefix(line.buf, "# pack-refs with:", &traits)) {1110 if (strstr(traits, " fully-peeled "))1111 peeled = PEELED_FULLY;1112 else if (strstr(traits, " peeled "))1113 peeled = PEELED_TAGS;1114 /* perhaps other traits later as well */1115 continue;1116 }11171118 refname = parse_ref_line(&line, sha1);1119 if (refname) {1120 int flag = REF_ISPACKED;11211122 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {1123 if (!refname_is_safe(refname))1124 die("packed refname is dangerous: %s", refname);1125 hashclr(sha1);1126 flag |= REF_BAD_NAME | REF_ISBROKEN;1127 }1128 last = create_ref_entry(refname, sha1, flag, 0);1129 if (peeled == PEELED_FULLY ||1130 (peeled == PEELED_TAGS && starts_with(refname, "refs/tags/")))1131 last->flag |= REF_KNOWS_PEELED;1132 add_ref(dir, last);1133 continue;1134 }1135 if (last &&1136 line.buf[0] == '^' &&1137 line.len == PEELED_LINE_LENGTH &&1138 line.buf[PEELED_LINE_LENGTH - 1] == '\n' &&1139 !get_sha1_hex(line.buf + 1, sha1)) {1140 hashcpy(last->u.value.peeled.hash, sha1);1141 /*1142 * Regardless of what the file header said,1143 * we definitely know the value of *this*1144 * reference:1145 */1146 last->flag |= REF_KNOWS_PEELED;1147 }1148 }11491150 strbuf_release(&line);1151}11521153/*1154 * Get the packed_ref_cache for the specified files_ref_store,1155 * creating it if necessary.1156 */1157static struct packed_ref_cache *get_packed_ref_cache(struct files_ref_store *refs)1158{1159 char *packed_refs_file;11601161 if (*refs->submodule)1162 packed_refs_file = git_pathdup_submodule(refs->submodule,1163 "packed-refs");1164 else1165 packed_refs_file = git_pathdup("packed-refs");11661167 if (refs->packed &&1168 !stat_validity_check(&refs->packed->validity, packed_refs_file))1169 clear_packed_ref_cache(refs);11701171 if (!refs->packed) {1172 FILE *f;11731174 refs->packed = xcalloc(1, sizeof(*refs->packed));1175 acquire_packed_ref_cache(refs->packed);1176 refs->packed->root = create_dir_entry(refs, "", 0, 0);1177 f = fopen(packed_refs_file, "r");1178 if (f) {1179 stat_validity_update(&refs->packed->validity, fileno(f));1180 read_packed_refs(f, get_ref_dir(refs->packed->root));1181 fclose(f);1182 }1183 }1184 free(packed_refs_file);1185 return refs->packed;1186}11871188static struct ref_dir *get_packed_ref_dir(struct packed_ref_cache *packed_ref_cache)1189{1190 return get_ref_dir(packed_ref_cache->root);1191}11921193static struct ref_dir *get_packed_refs(struct files_ref_store *refs)1194{1195 return get_packed_ref_dir(get_packed_ref_cache(refs));1196}11971198/*1199 * Add a reference to the in-memory packed reference cache. This may1200 * only be called while the packed-refs file is locked (see1201 * lock_packed_refs()). To actually write the packed-refs file, call1202 * commit_packed_refs().1203 */1204static void add_packed_ref(struct files_ref_store *refs,1205 const char *refname, const unsigned char *sha1)1206{1207 struct packed_ref_cache *packed_ref_cache = get_packed_ref_cache(refs);12081209 if (!packed_ref_cache->lock)1210 die("internal error: packed refs not locked");1211 add_ref(get_packed_ref_dir(packed_ref_cache),1212 create_ref_entry(refname, sha1, REF_ISPACKED, 1));1213}12141215/*1216 * Read the loose references from the namespace dirname into dir1217 * (without recursing). dirname must end with '/'. dir must be the1218 * directory entry corresponding to dirname.1219 */1220static void read_loose_refs(const char *dirname, struct ref_dir *dir)1221{1222 struct files_ref_store *refs = dir->ref_store;1223 DIR *d;1224 struct dirent *de;1225 int dirnamelen = strlen(dirname);1226 struct strbuf refname;1227 struct strbuf path = STRBUF_INIT;1228 size_t path_baselen;1229 int err = 0;12301231 if (*refs->submodule)1232 err = strbuf_git_path_submodule(&path, refs->submodule, "%s", dirname);1233 else1234 strbuf_git_path(&path, "%s", dirname);1235 path_baselen = path.len;12361237 if (err) {1238 strbuf_release(&path);1239 return;1240 }12411242 d = opendir(path.buf);1243 if (!d) {1244 strbuf_release(&path);1245 return;1246 }12471248 strbuf_init(&refname, dirnamelen + 257);1249 strbuf_add(&refname, dirname, dirnamelen);12501251 while ((de = readdir(d)) != NULL) {1252 unsigned char sha1[20];1253 struct stat st;1254 int flag;12551256 if (de->d_name[0] == '.')1257 continue;1258 if (ends_with(de->d_name, ".lock"))1259 continue;1260 strbuf_addstr(&refname, de->d_name);1261 strbuf_addstr(&path, de->d_name);1262 if (stat(path.buf, &st) < 0) {1263 ; /* silently ignore */1264 } else if (S_ISDIR(st.st_mode)) {1265 strbuf_addch(&refname, '/');1266 add_entry_to_dir(dir,1267 create_dir_entry(refs, refname.buf,1268 refname.len, 1));1269 } else {1270 int read_ok;12711272 if (*refs->submodule) {1273 hashclr(sha1);1274 flag = 0;1275 read_ok = !resolve_gitlink_ref(refs->submodule,1276 refname.buf, sha1);1277 } else {1278 read_ok = !read_ref_full(refname.buf,1279 RESOLVE_REF_READING,1280 sha1, &flag);1281 }12821283 if (!read_ok) {1284 hashclr(sha1);1285 flag |= REF_ISBROKEN;1286 } else if (is_null_sha1(sha1)) {1287 /*1288 * It is so astronomically unlikely1289 * that NULL_SHA1 is the SHA-1 of an1290 * actual object that we consider its1291 * appearance in a loose reference1292 * file to be repo corruption1293 * (probably due to a software bug).1294 */1295 flag |= REF_ISBROKEN;1296 }12971298 if (check_refname_format(refname.buf,1299 REFNAME_ALLOW_ONELEVEL)) {1300 if (!refname_is_safe(refname.buf))1301 die("loose refname is dangerous: %s", refname.buf);1302 hashclr(sha1);1303 flag |= REF_BAD_NAME | REF_ISBROKEN;1304 }1305 add_entry_to_dir(dir,1306 create_ref_entry(refname.buf, sha1, flag, 0));1307 }1308 strbuf_setlen(&refname, dirnamelen);1309 strbuf_setlen(&path, path_baselen);1310 }1311 strbuf_release(&refname);1312 strbuf_release(&path);1313 closedir(d);1314}13151316static struct ref_dir *get_loose_refs(struct files_ref_store *refs)1317{1318 if (!refs->loose) {1319 /*1320 * Mark the top-level directory complete because we1321 * are about to read the only subdirectory that can1322 * hold references:1323 */1324 refs->loose = create_dir_entry(refs, "", 0, 0);1325 /*1326 * Create an incomplete entry for "refs/":1327 */1328 add_entry_to_dir(get_ref_dir(refs->loose),1329 create_dir_entry(refs, "refs/", 5, 1));1330 }1331 return get_ref_dir(refs->loose);1332}13331334/*1335 * Return the ref_entry for the given refname from the packed1336 * references. If it does not exist, return NULL.1337 */1338static struct ref_entry *get_packed_ref(struct files_ref_store *refs,1339 const char *refname)1340{1341 return find_ref(get_packed_refs(refs), refname);1342}13431344/*1345 * A loose ref file doesn't exist; check for a packed ref.1346 */1347static int resolve_packed_ref(struct files_ref_store *refs,1348 const char *refname,1349 unsigned char *sha1, unsigned int *flags)1350{1351 struct ref_entry *entry;13521353 /*1354 * The loose reference file does not exist; check for a packed1355 * reference.1356 */1357 entry = get_packed_ref(refs, refname);1358 if (entry) {1359 hashcpy(sha1, entry->u.value.oid.hash);1360 *flags |= REF_ISPACKED;1361 return 0;1362 }1363 /* refname is not a packed reference. */1364 return -1;1365}13661367static int files_read_raw_ref(struct ref_store *ref_store,1368 const char *refname, unsigned char *sha1,1369 struct strbuf *referent, unsigned int *type)1370{1371 struct files_ref_store *refs =1372 files_downcast(ref_store, 1, "read_raw_ref");1373 struct strbuf sb_contents = STRBUF_INIT;1374 struct strbuf sb_path = STRBUF_INIT;1375 const char *path;1376 const char *buf;1377 struct stat st;1378 int fd;1379 int ret = -1;1380 int save_errno;1381 int remaining_retries = 3;13821383 *type = 0;1384 strbuf_reset(&sb_path);13851386 if (*refs->submodule)1387 strbuf_git_path_submodule(&sb_path, refs->submodule, "%s", refname);1388 else1389 strbuf_git_path(&sb_path, "%s", refname);13901391 path = sb_path.buf;13921393stat_ref:1394 /*1395 * We might have to loop back here to avoid a race1396 * condition: first we lstat() the file, then we try1397 * to read it as a link or as a file. But if somebody1398 * changes the type of the file (file <-> directory1399 * <-> symlink) between the lstat() and reading, then1400 * we don't want to report that as an error but rather1401 * try again starting with the lstat().1402 *1403 * We'll keep a count of the retries, though, just to avoid1404 * any confusing situation sending us into an infinite loop.1405 */14061407 if (remaining_retries-- <= 0)1408 goto out;14091410 if (lstat(path, &st) < 0) {1411 if (errno != ENOENT)1412 goto out;1413 if (resolve_packed_ref(refs, refname, sha1, type)) {1414 errno = ENOENT;1415 goto out;1416 }1417 ret = 0;1418 goto out;1419 }14201421 /* Follow "normalized" - ie "refs/.." symlinks by hand */1422 if (S_ISLNK(st.st_mode)) {1423 strbuf_reset(&sb_contents);1424 if (strbuf_readlink(&sb_contents, path, 0) < 0) {1425 if (errno == ENOENT || errno == EINVAL)1426 /* inconsistent with lstat; retry */1427 goto stat_ref;1428 else1429 goto out;1430 }1431 if (starts_with(sb_contents.buf, "refs/") &&1432 !check_refname_format(sb_contents.buf, 0)) {1433 strbuf_swap(&sb_contents, referent);1434 *type |= REF_ISSYMREF;1435 ret = 0;1436 goto out;1437 }1438 /*1439 * It doesn't look like a refname; fall through to just1440 * treating it like a non-symlink, and reading whatever it1441 * points to.1442 */1443 }14441445 /* Is it a directory? */1446 if (S_ISDIR(st.st_mode)) {1447 /*1448 * Even though there is a directory where the loose1449 * ref is supposed to be, there could still be a1450 * packed ref:1451 */1452 if (resolve_packed_ref(refs, refname, sha1, type)) {1453 errno = EISDIR;1454 goto out;1455 }1456 ret = 0;1457 goto out;1458 }14591460 /*1461 * Anything else, just open it and try to use it as1462 * a ref1463 */1464 fd = open(path, O_RDONLY);1465 if (fd < 0) {1466 if (errno == ENOENT && !S_ISLNK(st.st_mode))1467 /* inconsistent with lstat; retry */1468 goto stat_ref;1469 else1470 goto out;1471 }1472 strbuf_reset(&sb_contents);1473 if (strbuf_read(&sb_contents, fd, 256) < 0) {1474 int save_errno = errno;1475 close(fd);1476 errno = save_errno;1477 goto out;1478 }1479 close(fd);1480 strbuf_rtrim(&sb_contents);1481 buf = sb_contents.buf;1482 if (starts_with(buf, "ref:")) {1483 buf += 4;1484 while (isspace(*buf))1485 buf++;14861487 strbuf_reset(referent);1488 strbuf_addstr(referent, buf);1489 *type |= REF_ISSYMREF;1490 ret = 0;1491 goto out;1492 }14931494 /*1495 * Please note that FETCH_HEAD has additional1496 * data after the sha.1497 */1498 if (get_sha1_hex(buf, sha1) ||1499 (buf[40] != '\0' && !isspace(buf[40]))) {1500 *type |= REF_ISBROKEN;1501 errno = EINVAL;1502 goto out;1503 }15041505 ret = 0;15061507out:1508 save_errno = errno;1509 strbuf_release(&sb_path);1510 strbuf_release(&sb_contents);1511 errno = save_errno;1512 return ret;1513}15141515static void unlock_ref(struct ref_lock *lock)1516{1517 /* Do not free lock->lk -- atexit() still looks at them */1518 if (lock->lk)1519 rollback_lock_file(lock->lk);1520 free(lock->ref_name);1521 free(lock);1522}15231524/*1525 * Lock refname, without following symrefs, and set *lock_p to point1526 * at a newly-allocated lock object. Fill in lock->old_oid, referent,1527 * and type similarly to read_raw_ref().1528 *1529 * The caller must verify that refname is a "safe" reference name (in1530 * the sense of refname_is_safe()) before calling this function.1531 *1532 * If the reference doesn't already exist, verify that refname doesn't1533 * have a D/F conflict with any existing references. extras and skip1534 * are passed to verify_refname_available_dir() for this check.1535 *1536 * If mustexist is not set and the reference is not found or is1537 * broken, lock the reference anyway but clear sha1.1538 *1539 * Return 0 on success. On failure, write an error message to err and1540 * return TRANSACTION_NAME_CONFLICT or TRANSACTION_GENERIC_ERROR.1541 *1542 * Implementation note: This function is basically1543 *1544 * lock reference1545 * read_raw_ref()1546 *1547 * but it includes a lot more code to1548 * - Deal with possible races with other processes1549 * - Avoid calling verify_refname_available_dir() when it can be1550 * avoided, namely if we were successfully able to read the ref1551 * - Generate informative error messages in the case of failure1552 */1553static int lock_raw_ref(struct files_ref_store *refs,1554 const char *refname, int mustexist,1555 const struct string_list *extras,1556 const struct string_list *skip,1557 struct ref_lock **lock_p,1558 struct strbuf *referent,1559 unsigned int *type,1560 struct strbuf *err)1561{1562 struct ref_lock *lock;1563 struct strbuf ref_file = STRBUF_INIT;1564 int attempts_remaining = 3;1565 int ret = TRANSACTION_GENERIC_ERROR;15661567 assert(err);1568 files_assert_main_repository(refs, "lock_raw_ref");15691570 *type = 0;15711572 /* First lock the file so it can't change out from under us. */15731574 *lock_p = lock = xcalloc(1, sizeof(*lock));15751576 lock->ref_name = xstrdup(refname);1577 strbuf_git_path(&ref_file, "%s", refname);15781579retry:1580 switch (safe_create_leading_directories(ref_file.buf)) {1581 case SCLD_OK:1582 break; /* success */1583 case SCLD_EXISTS:1584 /*1585 * Suppose refname is "refs/foo/bar". We just failed1586 * to create the containing directory, "refs/foo",1587 * because there was a non-directory in the way. This1588 * indicates a D/F conflict, probably because of1589 * another reference such as "refs/foo". There is no1590 * reason to expect this error to be transitory.1591 */1592 if (verify_refname_available(refname, extras, skip, err)) {1593 if (mustexist) {1594 /*1595 * To the user the relevant error is1596 * that the "mustexist" reference is1597 * missing:1598 */1599 strbuf_reset(err);1600 strbuf_addf(err, "unable to resolve reference '%s'",1601 refname);1602 } else {1603 /*1604 * The error message set by1605 * verify_refname_available_dir() is OK.1606 */1607 ret = TRANSACTION_NAME_CONFLICT;1608 }1609 } else {1610 /*1611 * The file that is in the way isn't a loose1612 * reference. Report it as a low-level1613 * failure.1614 */1615 strbuf_addf(err, "unable to create lock file %s.lock; "1616 "non-directory in the way",1617 ref_file.buf);1618 }1619 goto error_return;1620 case SCLD_VANISHED:1621 /* Maybe another process was tidying up. Try again. */1622 if (--attempts_remaining > 0)1623 goto retry;1624 /* fall through */1625 default:1626 strbuf_addf(err, "unable to create directory for %s",1627 ref_file.buf);1628 goto error_return;1629 }16301631 if (!lock->lk)1632 lock->lk = xcalloc(1, sizeof(struct lock_file));16331634 if (hold_lock_file_for_update(lock->lk, ref_file.buf, LOCK_NO_DEREF) < 0) {1635 if (errno == ENOENT && --attempts_remaining > 0) {1636 /*1637 * Maybe somebody just deleted one of the1638 * directories leading to ref_file. Try1639 * again:1640 */1641 goto retry;1642 } else {1643 unable_to_lock_message(ref_file.buf, errno, err);1644 goto error_return;1645 }1646 }16471648 /*1649 * Now we hold the lock and can read the reference without1650 * fear that its value will change.1651 */16521653 if (files_read_raw_ref(&refs->base, refname,1654 lock->old_oid.hash, referent, type)) {1655 if (errno == ENOENT) {1656 if (mustexist) {1657 /* Garden variety missing reference. */1658 strbuf_addf(err, "unable to resolve reference '%s'",1659 refname);1660 goto error_return;1661 } else {1662 /*1663 * Reference is missing, but that's OK. We1664 * know that there is not a conflict with1665 * another loose reference because1666 * (supposing that we are trying to lock1667 * reference "refs/foo/bar"):1668 *1669 * - We were successfully able to create1670 * the lockfile refs/foo/bar.lock, so we1671 * know there cannot be a loose reference1672 * named "refs/foo".1673 *1674 * - We got ENOENT and not EISDIR, so we1675 * know that there cannot be a loose1676 * reference named "refs/foo/bar/baz".1677 */1678 }1679 } else if (errno == EISDIR) {1680 /*1681 * There is a directory in the way. It might have1682 * contained references that have been deleted. If1683 * we don't require that the reference already1684 * exists, try to remove the directory so that it1685 * doesn't cause trouble when we want to rename the1686 * lockfile into place later.1687 */1688 if (mustexist) {1689 /* Garden variety missing reference. */1690 strbuf_addf(err, "unable to resolve reference '%s'",1691 refname);1692 goto error_return;1693 } else if (remove_dir_recursively(&ref_file,1694 REMOVE_DIR_EMPTY_ONLY)) {1695 if (verify_refname_available_dir(1696 refname, extras, skip,1697 get_loose_refs(refs),1698 err)) {1699 /*1700 * The error message set by1701 * verify_refname_available() is OK.1702 */1703 ret = TRANSACTION_NAME_CONFLICT;1704 goto error_return;1705 } else {1706 /*1707 * We can't delete the directory,1708 * but we also don't know of any1709 * references that it should1710 * contain.1711 */1712 strbuf_addf(err, "there is a non-empty directory '%s' "1713 "blocking reference '%s'",1714 ref_file.buf, refname);1715 goto error_return;1716 }1717 }1718 } else if (errno == EINVAL && (*type & REF_ISBROKEN)) {1719 strbuf_addf(err, "unable to resolve reference '%s': "1720 "reference broken", refname);1721 goto error_return;1722 } else {1723 strbuf_addf(err, "unable to resolve reference '%s': %s",1724 refname, strerror(errno));1725 goto error_return;1726 }17271728 /*1729 * If the ref did not exist and we are creating it,1730 * make sure there is no existing packed ref whose1731 * name begins with our refname, nor a packed ref1732 * whose name is a proper prefix of our refname.1733 */1734 if (verify_refname_available_dir(1735 refname, extras, skip,1736 get_packed_refs(refs),1737 err)) {1738 goto error_return;1739 }1740 }17411742 ret = 0;1743 goto out;17441745error_return:1746 unlock_ref(lock);1747 *lock_p = NULL;17481749out:1750 strbuf_release(&ref_file);1751 return ret;1752}17531754/*1755 * Peel the entry (if possible) and return its new peel_status. If1756 * repeel is true, re-peel the entry even if there is an old peeled1757 * value that is already stored in it.1758 *1759 * It is OK to call this function with a packed reference entry that1760 * might be stale and might even refer to an object that has since1761 * been garbage-collected. In such a case, if the entry has1762 * REF_KNOWS_PEELED then leave the status unchanged and return1763 * PEEL_PEELED or PEEL_NON_TAG; otherwise, return PEEL_INVALID.1764 */1765static enum peel_status peel_entry(struct ref_entry *entry, int repeel)1766{1767 enum peel_status status;17681769 if (entry->flag & REF_KNOWS_PEELED) {1770 if (repeel) {1771 entry->flag &= ~REF_KNOWS_PEELED;1772 oidclr(&entry->u.value.peeled);1773 } else {1774 return is_null_oid(&entry->u.value.peeled) ?1775 PEEL_NON_TAG : PEEL_PEELED;1776 }1777 }1778 if (entry->flag & REF_ISBROKEN)1779 return PEEL_BROKEN;1780 if (entry->flag & REF_ISSYMREF)1781 return PEEL_IS_SYMREF;17821783 status = peel_object(entry->u.value.oid.hash, entry->u.value.peeled.hash);1784 if (status == PEEL_PEELED || status == PEEL_NON_TAG)1785 entry->flag |= REF_KNOWS_PEELED;1786 return status;1787}17881789static int files_peel_ref(struct ref_store *ref_store,1790 const char *refname, unsigned char *sha1)1791{1792 struct files_ref_store *refs = files_downcast(ref_store, 0, "peel_ref");1793 int flag;1794 unsigned char base[20];17951796 if (current_ref_iter && current_ref_iter->refname == refname) {1797 struct object_id peeled;17981799 if (ref_iterator_peel(current_ref_iter, &peeled))1800 return -1;1801 hashcpy(sha1, peeled.hash);1802 return 0;1803 }18041805 if (read_ref_full(refname, RESOLVE_REF_READING, base, &flag))1806 return -1;18071808 /*1809 * If the reference is packed, read its ref_entry from the1810 * cache in the hope that we already know its peeled value.1811 * We only try this optimization on packed references because1812 * (a) forcing the filling of the loose reference cache could1813 * be expensive and (b) loose references anyway usually do not1814 * have REF_KNOWS_PEELED.1815 */1816 if (flag & REF_ISPACKED) {1817 struct ref_entry *r = get_packed_ref(refs, refname);1818 if (r) {1819 if (peel_entry(r, 0))1820 return -1;1821 hashcpy(sha1, r->u.value.peeled.hash);1822 return 0;1823 }1824 }18251826 return peel_object(base, sha1);1827}18281829struct files_ref_iterator {1830 struct ref_iterator base;18311832 struct packed_ref_cache *packed_ref_cache;1833 struct ref_iterator *iter0;1834 unsigned int flags;1835};18361837static int files_ref_iterator_advance(struct ref_iterator *ref_iterator)1838{1839 struct files_ref_iterator *iter =1840 (struct files_ref_iterator *)ref_iterator;1841 int ok;18421843 while ((ok = ref_iterator_advance(iter->iter0)) == ITER_OK) {1844 if (iter->flags & DO_FOR_EACH_PER_WORKTREE_ONLY &&1845 ref_type(iter->iter0->refname) != REF_TYPE_PER_WORKTREE)1846 continue;18471848 if (!(iter->flags & DO_FOR_EACH_INCLUDE_BROKEN) &&1849 !ref_resolves_to_object(iter->iter0->refname,1850 iter->iter0->oid,1851 iter->iter0->flags))1852 continue;18531854 iter->base.refname = iter->iter0->refname;1855 iter->base.oid = iter->iter0->oid;1856 iter->base.flags = iter->iter0->flags;1857 return ITER_OK;1858 }18591860 iter->iter0 = NULL;1861 if (ref_iterator_abort(ref_iterator) != ITER_DONE)1862 ok = ITER_ERROR;18631864 return ok;1865}18661867static int files_ref_iterator_peel(struct ref_iterator *ref_iterator,1868 struct object_id *peeled)1869{1870 struct files_ref_iterator *iter =1871 (struct files_ref_iterator *)ref_iterator;18721873 return ref_iterator_peel(iter->iter0, peeled);1874}18751876static int files_ref_iterator_abort(struct ref_iterator *ref_iterator)1877{1878 struct files_ref_iterator *iter =1879 (struct files_ref_iterator *)ref_iterator;1880 int ok = ITER_DONE;18811882 if (iter->iter0)1883 ok = ref_iterator_abort(iter->iter0);18841885 release_packed_ref_cache(iter->packed_ref_cache);1886 base_ref_iterator_free(ref_iterator);1887 return ok;1888}18891890static struct ref_iterator_vtable files_ref_iterator_vtable = {1891 files_ref_iterator_advance,1892 files_ref_iterator_peel,1893 files_ref_iterator_abort1894};18951896static struct ref_iterator *files_ref_iterator_begin(1897 struct ref_store *ref_store,1898 const char *prefix, unsigned int flags)1899{1900 struct files_ref_store *refs =1901 files_downcast(ref_store, 1, "ref_iterator_begin");1902 struct ref_dir *loose_dir, *packed_dir;1903 struct ref_iterator *loose_iter, *packed_iter;1904 struct files_ref_iterator *iter;1905 struct ref_iterator *ref_iterator;19061907 if (!refs)1908 return empty_ref_iterator_begin();19091910 if (ref_paranoia < 0)1911 ref_paranoia = git_env_bool("GIT_REF_PARANOIA", 0);1912 if (ref_paranoia)1913 flags |= DO_FOR_EACH_INCLUDE_BROKEN;19141915 iter = xcalloc(1, sizeof(*iter));1916 ref_iterator = &iter->base;1917 base_ref_iterator_init(ref_iterator, &files_ref_iterator_vtable);19181919 /*1920 * We must make sure that all loose refs are read before1921 * accessing the packed-refs file; this avoids a race1922 * condition if loose refs are migrated to the packed-refs1923 * file by a simultaneous process, but our in-memory view is1924 * from before the migration. We ensure this as follows:1925 * First, we call prime_ref_dir(), which pre-reads the loose1926 * references for the subtree into the cache. (If they've1927 * already been read, that's OK; we only need to guarantee1928 * that they're read before the packed refs, not *how much*1929 * before.) After that, we call get_packed_ref_cache(), which1930 * internally checks whether the packed-ref cache is up to1931 * date with what is on disk, and re-reads it if not.1932 */19331934 loose_dir = get_loose_refs(refs);19351936 if (prefix && *prefix)1937 loose_dir = find_containing_dir(loose_dir, prefix, 0);19381939 if (loose_dir) {1940 prime_ref_dir(loose_dir);1941 loose_iter = cache_ref_iterator_begin(loose_dir);1942 } else {1943 /* There's nothing to iterate over. */1944 loose_iter = empty_ref_iterator_begin();1945 }19461947 iter->packed_ref_cache = get_packed_ref_cache(refs);1948 acquire_packed_ref_cache(iter->packed_ref_cache);1949 packed_dir = get_packed_ref_dir(iter->packed_ref_cache);19501951 if (prefix && *prefix)1952 packed_dir = find_containing_dir(packed_dir, prefix, 0);19531954 if (packed_dir) {1955 packed_iter = cache_ref_iterator_begin(packed_dir);1956 } else {1957 /* There's nothing to iterate over. */1958 packed_iter = empty_ref_iterator_begin();1959 }19601961 iter->iter0 = overlay_ref_iterator_begin(loose_iter, packed_iter);1962 iter->flags = flags;19631964 return ref_iterator;1965}19661967/*1968 * Verify that the reference locked by lock has the value old_sha1.1969 * Fail if the reference doesn't exist and mustexist is set. Return 01970 * on success. On error, write an error message to err, set errno, and1971 * return a negative value.1972 */1973static int verify_lock(struct ref_lock *lock,1974 const unsigned char *old_sha1, int mustexist,1975 struct strbuf *err)1976{1977 assert(err);19781979 if (read_ref_full(lock->ref_name,1980 mustexist ? RESOLVE_REF_READING : 0,1981 lock->old_oid.hash, NULL)) {1982 if (old_sha1) {1983 int save_errno = errno;1984 strbuf_addf(err, "can't verify ref '%s'", lock->ref_name);1985 errno = save_errno;1986 return -1;1987 } else {1988 oidclr(&lock->old_oid);1989 return 0;1990 }1991 }1992 if (old_sha1 && hashcmp(lock->old_oid.hash, old_sha1)) {1993 strbuf_addf(err, "ref '%s' is at %s but expected %s",1994 lock->ref_name,1995 oid_to_hex(&lock->old_oid),1996 sha1_to_hex(old_sha1));1997 errno = EBUSY;1998 return -1;1999 }2000 return 0;2001}20022003static int remove_empty_directories(struct strbuf *path)2004{2005 /*2006 * we want to create a file but there is a directory there;2007 * if that is an empty directory (or a directory that contains2008 * only empty directories), remove them.2009 */2010 return remove_dir_recursively(path, REMOVE_DIR_EMPTY_ONLY);2011}20122013/*2014 * Locks a ref returning the lock on success and NULL on failure.2015 * On failure errno is set to something meaningful.2016 */2017static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs,2018 const char *refname,2019 const unsigned char *old_sha1,2020 const struct string_list *extras,2021 const struct string_list *skip,2022 unsigned int flags, int *type,2023 struct strbuf *err)2024{2025 struct strbuf ref_file = STRBUF_INIT;2026 struct ref_lock *lock;2027 int last_errno = 0;2028 int lflags = LOCK_NO_DEREF;2029 int mustexist = (old_sha1 && !is_null_sha1(old_sha1));2030 int resolve_flags = RESOLVE_REF_NO_RECURSE;2031 int attempts_remaining = 3;2032 int resolved;20332034 files_assert_main_repository(refs, "lock_ref_sha1_basic");2035 assert(err);20362037 lock = xcalloc(1, sizeof(struct ref_lock));20382039 if (mustexist)2040 resolve_flags |= RESOLVE_REF_READING;2041 if (flags & REF_DELETING)2042 resolve_flags |= RESOLVE_REF_ALLOW_BAD_NAME;20432044 strbuf_git_path(&ref_file, "%s", refname);2045 resolved = !!resolve_ref_unsafe(refname, resolve_flags,2046 lock->old_oid.hash, type);2047 if (!resolved && errno == EISDIR) {2048 /*2049 * we are trying to lock foo but we used to2050 * have foo/bar which now does not exist;2051 * it is normal for the empty directory 'foo'2052 * to remain.2053 */2054 if (remove_empty_directories(&ref_file)) {2055 last_errno = errno;2056 if (!verify_refname_available_dir(2057 refname, extras, skip,2058 get_loose_refs(refs), err))2059 strbuf_addf(err, "there are still refs under '%s'",2060 refname);2061 goto error_return;2062 }2063 resolved = !!resolve_ref_unsafe(refname, resolve_flags,2064 lock->old_oid.hash, type);2065 }2066 if (!resolved) {2067 last_errno = errno;2068 if (last_errno != ENOTDIR ||2069 !verify_refname_available_dir(2070 refname, extras, skip,2071 get_loose_refs(refs), err))2072 strbuf_addf(err, "unable to resolve reference '%s': %s",2073 refname, strerror(last_errno));20742075 goto error_return;2076 }20772078 /*2079 * If the ref did not exist and we are creating it, make sure2080 * there is no existing packed ref whose name begins with our2081 * refname, nor a packed ref whose name is a proper prefix of2082 * our refname.2083 */2084 if (is_null_oid(&lock->old_oid) &&2085 verify_refname_available_dir(refname, extras, skip,2086 get_packed_refs(refs),2087 err)) {2088 last_errno = ENOTDIR;2089 goto error_return;2090 }20912092 lock->lk = xcalloc(1, sizeof(struct lock_file));20932094 lock->ref_name = xstrdup(refname);20952096 retry:2097 switch (safe_create_leading_directories_const(ref_file.buf)) {2098 case SCLD_OK:2099 break; /* success */2100 case SCLD_VANISHED:2101 if (--attempts_remaining > 0)2102 goto retry;2103 /* fall through */2104 default:2105 last_errno = errno;2106 strbuf_addf(err, "unable to create directory for '%s'",2107 ref_file.buf);2108 goto error_return;2109 }21102111 if (hold_lock_file_for_update(lock->lk, ref_file.buf, lflags) < 0) {2112 last_errno = errno;2113 if (errno == ENOENT && --attempts_remaining > 0)2114 /*2115 * Maybe somebody just deleted one of the2116 * directories leading to ref_file. Try2117 * again:2118 */2119 goto retry;2120 else {2121 unable_to_lock_message(ref_file.buf, errno, err);2122 goto error_return;2123 }2124 }2125 if (verify_lock(lock, old_sha1, mustexist, err)) {2126 last_errno = errno;2127 goto error_return;2128 }2129 goto out;21302131 error_return:2132 unlock_ref(lock);2133 lock = NULL;21342135 out:2136 strbuf_release(&ref_file);2137 errno = last_errno;2138 return lock;2139}21402141/*2142 * Write an entry to the packed-refs file for the specified refname.2143 * If peeled is non-NULL, write it as the entry's peeled value.2144 */2145static void write_packed_entry(FILE *fh, char *refname, unsigned char *sha1,2146 unsigned char *peeled)2147{2148 fprintf_or_die(fh, "%s %s\n", sha1_to_hex(sha1), refname);2149 if (peeled)2150 fprintf_or_die(fh, "^%s\n", sha1_to_hex(peeled));2151}21522153/*2154 * An each_ref_entry_fn that writes the entry to a packed-refs file.2155 */2156static int write_packed_entry_fn(struct ref_entry *entry, void *cb_data)2157{2158 enum peel_status peel_status = peel_entry(entry, 0);21592160 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)2161 error("internal error: %s is not a valid packed reference!",2162 entry->name);2163 write_packed_entry(cb_data, entry->name, entry->u.value.oid.hash,2164 peel_status == PEEL_PEELED ?2165 entry->u.value.peeled.hash : NULL);2166 return 0;2167}21682169/*2170 * Lock the packed-refs file for writing. Flags is passed to2171 * hold_lock_file_for_update(). Return 0 on success. On errors, set2172 * errno appropriately and return a nonzero value.2173 */2174static int lock_packed_refs(struct files_ref_store *refs, int flags)2175{2176 static int timeout_configured = 0;2177 static int timeout_value = 1000;2178 struct packed_ref_cache *packed_ref_cache;21792180 files_assert_main_repository(refs, "lock_packed_refs");21812182 if (!timeout_configured) {2183 git_config_get_int("core.packedrefstimeout", &timeout_value);2184 timeout_configured = 1;2185 }21862187 if (hold_lock_file_for_update_timeout(2188 &packlock, git_path("packed-refs"),2189 flags, timeout_value) < 0)2190 return -1;2191 /*2192 * Get the current packed-refs while holding the lock. If the2193 * packed-refs file has been modified since we last read it,2194 * this will automatically invalidate the cache and re-read2195 * the packed-refs file.2196 */2197 packed_ref_cache = get_packed_ref_cache(refs);2198 packed_ref_cache->lock = &packlock;2199 /* Increment the reference count to prevent it from being freed: */2200 acquire_packed_ref_cache(packed_ref_cache);2201 return 0;2202}22032204/*2205 * Write the current version of the packed refs cache from memory to2206 * disk. The packed-refs file must already be locked for writing (see2207 * lock_packed_refs()). Return zero on success. On errors, set errno2208 * and return a nonzero value2209 */2210static int commit_packed_refs(struct files_ref_store *refs)2211{2212 struct packed_ref_cache *packed_ref_cache =2213 get_packed_ref_cache(refs);2214 int error = 0;2215 int save_errno = 0;2216 FILE *out;22172218 files_assert_main_repository(refs, "commit_packed_refs");22192220 if (!packed_ref_cache->lock)2221 die("internal error: packed-refs not locked");22222223 out = fdopen_lock_file(packed_ref_cache->lock, "w");2224 if (!out)2225 die_errno("unable to fdopen packed-refs descriptor");22262227 fprintf_or_die(out, "%s", PACKED_REFS_HEADER);2228 do_for_each_entry_in_dir(get_packed_ref_dir(packed_ref_cache),2229 0, write_packed_entry_fn, out);22302231 if (commit_lock_file(packed_ref_cache->lock)) {2232 save_errno = errno;2233 error = -1;2234 }2235 packed_ref_cache->lock = NULL;2236 release_packed_ref_cache(packed_ref_cache);2237 errno = save_errno;2238 return error;2239}22402241/*2242 * Rollback the lockfile for the packed-refs file, and discard the2243 * in-memory packed reference cache. (The packed-refs file will be2244 * read anew if it is needed again after this function is called.)2245 */2246static void rollback_packed_refs(struct files_ref_store *refs)2247{2248 struct packed_ref_cache *packed_ref_cache =2249 get_packed_ref_cache(refs);22502251 files_assert_main_repository(refs, "rollback_packed_refs");22522253 if (!packed_ref_cache->lock)2254 die("internal error: packed-refs not locked");2255 rollback_lock_file(packed_ref_cache->lock);2256 packed_ref_cache->lock = NULL;2257 release_packed_ref_cache(packed_ref_cache);2258 clear_packed_ref_cache(refs);2259}22602261struct ref_to_prune {2262 struct ref_to_prune *next;2263 unsigned char sha1[20];2264 char name[FLEX_ARRAY];2265};22662267struct pack_refs_cb_data {2268 unsigned int flags;2269 struct ref_dir *packed_refs;2270 struct ref_to_prune *ref_to_prune;2271};22722273/*2274 * An each_ref_entry_fn that is run over loose references only. If2275 * the loose reference can be packed, add an entry in the packed ref2276 * cache. If the reference should be pruned, also add it to2277 * ref_to_prune in the pack_refs_cb_data.2278 */2279static int pack_if_possible_fn(struct ref_entry *entry, void *cb_data)2280{2281 struct pack_refs_cb_data *cb = cb_data;2282 enum peel_status peel_status;2283 struct ref_entry *packed_entry;2284 int is_tag_ref = starts_with(entry->name, "refs/tags/");22852286 /* Do not pack per-worktree refs: */2287 if (ref_type(entry->name) != REF_TYPE_NORMAL)2288 return 0;22892290 /* ALWAYS pack tags */2291 if (!(cb->flags & PACK_REFS_ALL) && !is_tag_ref)2292 return 0;22932294 /* Do not pack symbolic or broken refs: */2295 if ((entry->flag & REF_ISSYMREF) || !entry_resolves_to_object(entry))2296 return 0;22972298 /* Add a packed ref cache entry equivalent to the loose entry. */2299 peel_status = peel_entry(entry, 1);2300 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)2301 die("internal error peeling reference %s (%s)",2302 entry->name, oid_to_hex(&entry->u.value.oid));2303 packed_entry = find_ref(cb->packed_refs, entry->name);2304 if (packed_entry) {2305 /* Overwrite existing packed entry with info from loose entry */2306 packed_entry->flag = REF_ISPACKED | REF_KNOWS_PEELED;2307 oidcpy(&packed_entry->u.value.oid, &entry->u.value.oid);2308 } else {2309 packed_entry = create_ref_entry(entry->name, entry->u.value.oid.hash,2310 REF_ISPACKED | REF_KNOWS_PEELED, 0);2311 add_ref(cb->packed_refs, packed_entry);2312 }2313 oidcpy(&packed_entry->u.value.peeled, &entry->u.value.peeled);23142315 /* Schedule the loose reference for pruning if requested. */2316 if ((cb->flags & PACK_REFS_PRUNE)) {2317 struct ref_to_prune *n;2318 FLEX_ALLOC_STR(n, name, entry->name);2319 hashcpy(n->sha1, entry->u.value.oid.hash);2320 n->next = cb->ref_to_prune;2321 cb->ref_to_prune = n;2322 }2323 return 0;2324}23252326/*2327 * Remove empty parents, but spare refs/ and immediate subdirs.2328 * Note: munges *name.2329 */2330static void try_remove_empty_parents(char *name)2331{2332 char *p, *q;2333 int i;2334 p = name;2335 for (i = 0; i < 2; i++) { /* refs/{heads,tags,...}/ */2336 while (*p && *p != '/')2337 p++;2338 /* tolerate duplicate slashes; see check_refname_format() */2339 while (*p == '/')2340 p++;2341 }2342 for (q = p; *q; q++)2343 ;2344 while (1) {2345 while (q > p && *q != '/')2346 q--;2347 while (q > p && *(q-1) == '/')2348 q--;2349 if (q == p)2350 break;2351 *q = '\0';2352 if (rmdir(git_path("%s", name)))2353 break;2354 }2355}23562357/* make sure nobody touched the ref, and unlink */2358static void prune_ref(struct ref_to_prune *r)2359{2360 struct ref_transaction *transaction;2361 struct strbuf err = STRBUF_INIT;23622363 if (check_refname_format(r->name, 0))2364 return;23652366 transaction = ref_transaction_begin(&err);2367 if (!transaction ||2368 ref_transaction_delete(transaction, r->name, r->sha1,2369 REF_ISPRUNING | REF_NODEREF, NULL, &err) ||2370 ref_transaction_commit(transaction, &err)) {2371 ref_transaction_free(transaction);2372 error("%s", err.buf);2373 strbuf_release(&err);2374 return;2375 }2376 ref_transaction_free(transaction);2377 strbuf_release(&err);2378 try_remove_empty_parents(r->name);2379}23802381static void prune_refs(struct ref_to_prune *r)2382{2383 while (r) {2384 prune_ref(r);2385 r = r->next;2386 }2387}23882389static int files_pack_refs(struct ref_store *ref_store, unsigned int flags)2390{2391 struct files_ref_store *refs =2392 files_downcast(ref_store, 0, "pack_refs");2393 struct pack_refs_cb_data cbdata;23942395 memset(&cbdata, 0, sizeof(cbdata));2396 cbdata.flags = flags;23972398 lock_packed_refs(refs, LOCK_DIE_ON_ERROR);2399 cbdata.packed_refs = get_packed_refs(refs);24002401 do_for_each_entry_in_dir(get_loose_refs(refs), 0,2402 pack_if_possible_fn, &cbdata);24032404 if (commit_packed_refs(refs))2405 die_errno("unable to overwrite old ref-pack file");24062407 prune_refs(cbdata.ref_to_prune);2408 return 0;2409}24102411/*2412 * Rewrite the packed-refs file, omitting any refs listed in2413 * 'refnames'. On error, leave packed-refs unchanged, write an error2414 * message to 'err', and return a nonzero value.2415 *2416 * The refs in 'refnames' needn't be sorted. `err` must not be NULL.2417 */2418static int repack_without_refs(struct files_ref_store *refs,2419 struct string_list *refnames, struct strbuf *err)2420{2421 struct ref_dir *packed;2422 struct string_list_item *refname;2423 int ret, needs_repacking = 0, removed = 0;24242425 files_assert_main_repository(refs, "repack_without_refs");2426 assert(err);24272428 /* Look for a packed ref */2429 for_each_string_list_item(refname, refnames) {2430 if (get_packed_ref(refs, refname->string)) {2431 needs_repacking = 1;2432 break;2433 }2434 }24352436 /* Avoid locking if we have nothing to do */2437 if (!needs_repacking)2438 return 0; /* no refname exists in packed refs */24392440 if (lock_packed_refs(refs, 0)) {2441 unable_to_lock_message(git_path("packed-refs"), errno, err);2442 return -1;2443 }2444 packed = get_packed_refs(refs);24452446 /* Remove refnames from the cache */2447 for_each_string_list_item(refname, refnames)2448 if (remove_entry(packed, refname->string) != -1)2449 removed = 1;2450 if (!removed) {2451 /*2452 * All packed entries disappeared while we were2453 * acquiring the lock.2454 */2455 rollback_packed_refs(refs);2456 return 0;2457 }24582459 /* Write what remains */2460 ret = commit_packed_refs(refs);2461 if (ret)2462 strbuf_addf(err, "unable to overwrite old ref-pack file: %s",2463 strerror(errno));2464 return ret;2465}24662467static int delete_ref_loose(struct ref_lock *lock, int flag, struct strbuf *err)2468{2469 assert(err);24702471 if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {2472 /*2473 * loose. The loose file name is the same as the2474 * lockfile name, minus ".lock":2475 */2476 char *loose_filename = get_locked_file_path(lock->lk);2477 int res = unlink_or_msg(loose_filename, err);2478 free(loose_filename);2479 if (res)2480 return 1;2481 }2482 return 0;2483}24842485static int files_delete_refs(struct ref_store *ref_store,2486 struct string_list *refnames, unsigned int flags)2487{2488 struct files_ref_store *refs =2489 files_downcast(ref_store, 0, "delete_refs");2490 struct strbuf err = STRBUF_INIT;2491 int i, result = 0;24922493 if (!refnames->nr)2494 return 0;24952496 result = repack_without_refs(refs, refnames, &err);2497 if (result) {2498 /*2499 * If we failed to rewrite the packed-refs file, then2500 * it is unsafe to try to remove loose refs, because2501 * doing so might expose an obsolete packed value for2502 * a reference that might even point at an object that2503 * has been garbage collected.2504 */2505 if (refnames->nr == 1)2506 error(_("could not delete reference %s: %s"),2507 refnames->items[0].string, err.buf);2508 else2509 error(_("could not delete references: %s"), err.buf);25102511 goto out;2512 }25132514 for (i = 0; i < refnames->nr; i++) {2515 const char *refname = refnames->items[i].string;25162517 if (delete_ref(refname, NULL, flags))2518 result |= error(_("could not remove reference %s"), refname);2519 }25202521out:2522 strbuf_release(&err);2523 return result;2524}25252526/*2527 * People using contrib's git-new-workdir have .git/logs/refs ->2528 * /some/other/path/.git/logs/refs, and that may live on another device.2529 *2530 * IOW, to avoid cross device rename errors, the temporary renamed log must2531 * live into logs/refs.2532 */2533#define TMP_RENAMED_LOG "logs/refs/.tmp-renamed-log"25342535static int rename_tmp_log(const char *newrefname)2536{2537 int attempts_remaining = 4;2538 struct strbuf path = STRBUF_INIT;2539 int ret = -1;25402541 retry:2542 strbuf_reset(&path);2543 strbuf_git_path(&path, "logs/%s", newrefname);2544 switch (safe_create_leading_directories_const(path.buf)) {2545 case SCLD_OK:2546 break; /* success */2547 case SCLD_VANISHED:2548 if (--attempts_remaining > 0)2549 goto retry;2550 /* fall through */2551 default:2552 error("unable to create directory for %s", newrefname);2553 goto out;2554 }25552556 if (rename(git_path(TMP_RENAMED_LOG), path.buf)) {2557 if ((errno==EISDIR || errno==ENOTDIR) && --attempts_remaining > 0) {2558 /*2559 * rename(a, b) when b is an existing2560 * directory ought to result in ISDIR, but2561 * Solaris 5.8 gives ENOTDIR. Sheesh.2562 */2563 if (remove_empty_directories(&path)) {2564 error("Directory not empty: logs/%s", newrefname);2565 goto out;2566 }2567 goto retry;2568 } else if (errno == ENOENT && --attempts_remaining > 0) {2569 /*2570 * Maybe another process just deleted one of2571 * the directories in the path to newrefname.2572 * Try again from the beginning.2573 */2574 goto retry;2575 } else {2576 error("unable to move logfile "TMP_RENAMED_LOG" to logs/%s: %s",2577 newrefname, strerror(errno));2578 goto out;2579 }2580 }2581 ret = 0;2582out:2583 strbuf_release(&path);2584 return ret;2585}25862587static int files_verify_refname_available(struct ref_store *ref_store,2588 const char *newname,2589 const struct string_list *extras,2590 const struct string_list *skip,2591 struct strbuf *err)2592{2593 struct files_ref_store *refs =2594 files_downcast(ref_store, 1, "verify_refname_available");2595 struct ref_dir *packed_refs = get_packed_refs(refs);2596 struct ref_dir *loose_refs = get_loose_refs(refs);25972598 if (verify_refname_available_dir(newname, extras, skip,2599 packed_refs, err) ||2600 verify_refname_available_dir(newname, extras, skip,2601 loose_refs, err))2602 return -1;26032604 return 0;2605}26062607static int write_ref_to_lockfile(struct ref_lock *lock,2608 const unsigned char *sha1, struct strbuf *err);2609static int commit_ref_update(struct files_ref_store *refs,2610 struct ref_lock *lock,2611 const unsigned char *sha1, const char *logmsg,2612 struct strbuf *err);26132614static int files_rename_ref(struct ref_store *ref_store,2615 const char *oldrefname, const char *newrefname,2616 const char *logmsg)2617{2618 struct files_ref_store *refs =2619 files_downcast(ref_store, 0, "rename_ref");2620 unsigned char sha1[20], orig_sha1[20];2621 int flag = 0, logmoved = 0;2622 struct ref_lock *lock;2623 struct stat loginfo;2624 int log = !lstat(git_path("logs/%s", oldrefname), &loginfo);2625 struct strbuf err = STRBUF_INIT;26262627 if (log && S_ISLNK(loginfo.st_mode))2628 return error("reflog for %s is a symlink", oldrefname);26292630 if (!resolve_ref_unsafe(oldrefname, RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,2631 orig_sha1, &flag))2632 return error("refname %s not found", oldrefname);26332634 if (flag & REF_ISSYMREF)2635 return error("refname %s is a symbolic ref, renaming it is not supported",2636 oldrefname);2637 if (!rename_ref_available(oldrefname, newrefname))2638 return 1;26392640 if (log && rename(git_path("logs/%s", oldrefname), git_path(TMP_RENAMED_LOG)))2641 return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",2642 oldrefname, strerror(errno));26432644 if (delete_ref(oldrefname, orig_sha1, REF_NODEREF)) {2645 error("unable to delete old %s", oldrefname);2646 goto rollback;2647 }26482649 /*2650 * Since we are doing a shallow lookup, sha1 is not the2651 * correct value to pass to delete_ref as old_sha1. But that2652 * doesn't matter, because an old_sha1 check wouldn't add to2653 * the safety anyway; we want to delete the reference whatever2654 * its current value.2655 */2656 if (!read_ref_full(newrefname, RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,2657 sha1, NULL) &&2658 delete_ref(newrefname, NULL, REF_NODEREF)) {2659 if (errno==EISDIR) {2660 struct strbuf path = STRBUF_INIT;2661 int result;26622663 strbuf_git_path(&path, "%s", newrefname);2664 result = remove_empty_directories(&path);2665 strbuf_release(&path);26662667 if (result) {2668 error("Directory not empty: %s", newrefname);2669 goto rollback;2670 }2671 } else {2672 error("unable to delete existing %s", newrefname);2673 goto rollback;2674 }2675 }26762677 if (log && rename_tmp_log(newrefname))2678 goto rollback;26792680 logmoved = log;26812682 lock = lock_ref_sha1_basic(refs, newrefname, NULL, NULL, NULL,2683 REF_NODEREF, NULL, &err);2684 if (!lock) {2685 error("unable to rename '%s' to '%s': %s", oldrefname, newrefname, err.buf);2686 strbuf_release(&err);2687 goto rollback;2688 }2689 hashcpy(lock->old_oid.hash, orig_sha1);26902691 if (write_ref_to_lockfile(lock, orig_sha1, &err) ||2692 commit_ref_update(refs, lock, orig_sha1, logmsg, &err)) {2693 error("unable to write current sha1 into %s: %s", newrefname, err.buf);2694 strbuf_release(&err);2695 goto rollback;2696 }26972698 return 0;26992700 rollback:2701 lock = lock_ref_sha1_basic(refs, oldrefname, NULL, NULL, NULL,2702 REF_NODEREF, NULL, &err);2703 if (!lock) {2704 error("unable to lock %s for rollback: %s", oldrefname, err.buf);2705 strbuf_release(&err);2706 goto rollbacklog;2707 }27082709 flag = log_all_ref_updates;2710 log_all_ref_updates = 0;2711 if (write_ref_to_lockfile(lock, orig_sha1, &err) ||2712 commit_ref_update(refs, lock, orig_sha1, NULL, &err)) {2713 error("unable to write current sha1 into %s: %s", oldrefname, err.buf);2714 strbuf_release(&err);2715 }2716 log_all_ref_updates = flag;27172718 rollbacklog:2719 if (logmoved && rename(git_path("logs/%s", newrefname), git_path("logs/%s", oldrefname)))2720 error("unable to restore logfile %s from %s: %s",2721 oldrefname, newrefname, strerror(errno));2722 if (!logmoved && log &&2723 rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", oldrefname)))2724 error("unable to restore logfile %s from "TMP_RENAMED_LOG": %s",2725 oldrefname, strerror(errno));27262727 return 1;2728}27292730static int close_ref(struct ref_lock *lock)2731{2732 if (close_lock_file(lock->lk))2733 return -1;2734 return 0;2735}27362737static int commit_ref(struct ref_lock *lock)2738{2739 char *path = get_locked_file_path(lock->lk);2740 struct stat st;27412742 if (!lstat(path, &st) && S_ISDIR(st.st_mode)) {2743 /*2744 * There is a directory at the path we want to rename2745 * the lockfile to. Hopefully it is empty; try to2746 * delete it.2747 */2748 size_t len = strlen(path);2749 struct strbuf sb_path = STRBUF_INIT;27502751 strbuf_attach(&sb_path, path, len, len);27522753 /*2754 * If this fails, commit_lock_file() will also fail2755 * and will report the problem.2756 */2757 remove_empty_directories(&sb_path);2758 strbuf_release(&sb_path);2759 } else {2760 free(path);2761 }27622763 if (commit_lock_file(lock->lk))2764 return -1;2765 return 0;2766}27672768/*2769 * Create a reflog for a ref. If force_create = 0, the reflog will2770 * only be created for certain refs (those for which2771 * should_autocreate_reflog returns non-zero. Otherwise, create it2772 * regardless of the ref name. Fill in *err and return -1 on failure.2773 */2774static int log_ref_setup(const char *refname, struct strbuf *logfile, struct strbuf *err, int force_create)2775{2776 int logfd, oflags = O_APPEND | O_WRONLY;27772778 strbuf_git_path(logfile, "logs/%s", refname);2779 if (force_create || should_autocreate_reflog(refname)) {2780 if (safe_create_leading_directories(logfile->buf) < 0) {2781 strbuf_addf(err, "unable to create directory for '%s': "2782 "%s", logfile->buf, strerror(errno));2783 return -1;2784 }2785 oflags |= O_CREAT;2786 }27872788 logfd = open(logfile->buf, oflags, 0666);2789 if (logfd < 0) {2790 if (!(oflags & O_CREAT) && (errno == ENOENT || errno == EISDIR))2791 return 0;27922793 if (errno == EISDIR) {2794 if (remove_empty_directories(logfile)) {2795 strbuf_addf(err, "there are still logs under "2796 "'%s'", logfile->buf);2797 return -1;2798 }2799 logfd = open(logfile->buf, oflags, 0666);2800 }28012802 if (logfd < 0) {2803 strbuf_addf(err, "unable to append to '%s': %s",2804 logfile->buf, strerror(errno));2805 return -1;2806 }2807 }28082809 adjust_shared_perm(logfile->buf);2810 close(logfd);2811 return 0;2812}281328142815static int files_create_reflog(struct ref_store *ref_store,2816 const char *refname, int force_create,2817 struct strbuf *err)2818{2819 int ret;2820 struct strbuf sb = STRBUF_INIT;28212822 /* Check validity (but we don't need the result): */2823 files_downcast(ref_store, 0, "create_reflog");28242825 ret = log_ref_setup(refname, &sb, err, force_create);2826 strbuf_release(&sb);2827 return ret;2828}28292830static int log_ref_write_fd(int fd, const unsigned char *old_sha1,2831 const unsigned char *new_sha1,2832 const char *committer, const char *msg)2833{2834 int msglen, written;2835 unsigned maxlen, len;2836 char *logrec;28372838 msglen = msg ? strlen(msg) : 0;2839 maxlen = strlen(committer) + msglen + 100;2840 logrec = xmalloc(maxlen);2841 len = xsnprintf(logrec, maxlen, "%s %s %s\n",2842 sha1_to_hex(old_sha1),2843 sha1_to_hex(new_sha1),2844 committer);2845 if (msglen)2846 len += copy_reflog_msg(logrec + len - 1, msg) - 1;28472848 written = len <= maxlen ? write_in_full(fd, logrec, len) : -1;2849 free(logrec);2850 if (written != len)2851 return -1;28522853 return 0;2854}28552856static int log_ref_write_1(const char *refname, const unsigned char *old_sha1,2857 const unsigned char *new_sha1, const char *msg,2858 struct strbuf *logfile, int flags,2859 struct strbuf *err)2860{2861 int logfd, result, oflags = O_APPEND | O_WRONLY;28622863 if (log_all_ref_updates < 0)2864 log_all_ref_updates = !is_bare_repository();28652866 result = log_ref_setup(refname, logfile, err, flags & REF_FORCE_CREATE_REFLOG);28672868 if (result)2869 return result;28702871 logfd = open(logfile->buf, oflags);2872 if (logfd < 0)2873 return 0;2874 result = log_ref_write_fd(logfd, old_sha1, new_sha1,2875 git_committer_info(0), msg);2876 if (result) {2877 strbuf_addf(err, "unable to append to '%s': %s", logfile->buf,2878 strerror(errno));2879 close(logfd);2880 return -1;2881 }2882 if (close(logfd)) {2883 strbuf_addf(err, "unable to append to '%s': %s", logfile->buf,2884 strerror(errno));2885 return -1;2886 }2887 return 0;2888}28892890static int log_ref_write(const char *refname, const unsigned char *old_sha1,2891 const unsigned char *new_sha1, const char *msg,2892 int flags, struct strbuf *err)2893{2894 return files_log_ref_write(refname, old_sha1, new_sha1, msg, flags,2895 err);2896}28972898int files_log_ref_write(const char *refname, const unsigned char *old_sha1,2899 const unsigned char *new_sha1, const char *msg,2900 int flags, struct strbuf *err)2901{2902 struct strbuf sb = STRBUF_INIT;2903 int ret = log_ref_write_1(refname, old_sha1, new_sha1, msg, &sb, flags,2904 err);2905 strbuf_release(&sb);2906 return ret;2907}29082909/*2910 * Write sha1 into the open lockfile, then close the lockfile. On2911 * errors, rollback the lockfile, fill in *err and2912 * return -1.2913 */2914static int write_ref_to_lockfile(struct ref_lock *lock,2915 const unsigned char *sha1, struct strbuf *err)2916{2917 static char term = '\n';2918 struct object *o;2919 int fd;29202921 o = parse_object(sha1);2922 if (!o) {2923 strbuf_addf(err,2924 "trying to write ref '%s' with nonexistent object %s",2925 lock->ref_name, sha1_to_hex(sha1));2926 unlock_ref(lock);2927 return -1;2928 }2929 if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {2930 strbuf_addf(err,2931 "trying to write non-commit object %s to branch '%s'",2932 sha1_to_hex(sha1), lock->ref_name);2933 unlock_ref(lock);2934 return -1;2935 }2936 fd = get_lock_file_fd(lock->lk);2937 if (write_in_full(fd, sha1_to_hex(sha1), 40) != 40 ||2938 write_in_full(fd, &term, 1) != 1 ||2939 close_ref(lock) < 0) {2940 strbuf_addf(err,2941 "couldn't write '%s'", get_lock_file_path(lock->lk));2942 unlock_ref(lock);2943 return -1;2944 }2945 return 0;2946}29472948/*2949 * Commit a change to a loose reference that has already been written2950 * to the loose reference lockfile. Also update the reflogs if2951 * necessary, using the specified lockmsg (which can be NULL).2952 */2953static int commit_ref_update(struct files_ref_store *refs,2954 struct ref_lock *lock,2955 const unsigned char *sha1, const char *logmsg,2956 struct strbuf *err)2957{2958 files_assert_main_repository(refs, "commit_ref_update");29592960 clear_loose_ref_cache(refs);2961 if (log_ref_write(lock->ref_name, lock->old_oid.hash, sha1, logmsg, 0, err)) {2962 char *old_msg = strbuf_detach(err, NULL);2963 strbuf_addf(err, "cannot update the ref '%s': %s",2964 lock->ref_name, old_msg);2965 free(old_msg);2966 unlock_ref(lock);2967 return -1;2968 }29692970 if (strcmp(lock->ref_name, "HEAD") != 0) {2971 /*2972 * Special hack: If a branch is updated directly and HEAD2973 * points to it (may happen on the remote side of a push2974 * for example) then logically the HEAD reflog should be2975 * updated too.2976 * A generic solution implies reverse symref information,2977 * but finding all symrefs pointing to the given branch2978 * would be rather costly for this rare event (the direct2979 * update of a branch) to be worth it. So let's cheat and2980 * check with HEAD only which should cover 99% of all usage2981 * scenarios (even 100% of the default ones).2982 */2983 unsigned char head_sha1[20];2984 int head_flag;2985 const char *head_ref;29862987 head_ref = resolve_ref_unsafe("HEAD", RESOLVE_REF_READING,2988 head_sha1, &head_flag);2989 if (head_ref && (head_flag & REF_ISSYMREF) &&2990 !strcmp(head_ref, lock->ref_name)) {2991 struct strbuf log_err = STRBUF_INIT;2992 if (log_ref_write("HEAD", lock->old_oid.hash, sha1,2993 logmsg, 0, &log_err)) {2994 error("%s", log_err.buf);2995 strbuf_release(&log_err);2996 }2997 }2998 }29993000 if (commit_ref(lock)) {3001 strbuf_addf(err, "couldn't set '%s'", lock->ref_name);3002 unlock_ref(lock);3003 return -1;3004 }30053006 unlock_ref(lock);3007 return 0;3008}30093010static int create_ref_symlink(struct ref_lock *lock, const char *target)3011{3012 int ret = -1;3013#ifndef NO_SYMLINK_HEAD3014 char *ref_path = get_locked_file_path(lock->lk);3015 unlink(ref_path);3016 ret = symlink(target, ref_path);3017 free(ref_path);30183019 if (ret)3020 fprintf(stderr, "no symlink - falling back to symbolic ref\n");3021#endif3022 return ret;3023}30243025static void update_symref_reflog(struct ref_lock *lock, const char *refname,3026 const char *target, const char *logmsg)3027{3028 struct strbuf err = STRBUF_INIT;3029 unsigned char new_sha1[20];3030 if (logmsg && !read_ref(target, new_sha1) &&3031 log_ref_write(refname, lock->old_oid.hash, new_sha1, logmsg, 0, &err)) {3032 error("%s", err.buf);3033 strbuf_release(&err);3034 }3035}30363037static int create_symref_locked(struct ref_lock *lock, const char *refname,3038 const char *target, const char *logmsg)3039{3040 if (prefer_symlink_refs && !create_ref_symlink(lock, target)) {3041 update_symref_reflog(lock, refname, target, logmsg);3042 return 0;3043 }30443045 if (!fdopen_lock_file(lock->lk, "w"))3046 return error("unable to fdopen %s: %s",3047 lock->lk->tempfile.filename.buf, strerror(errno));30483049 update_symref_reflog(lock, refname, target, logmsg);30503051 /* no error check; commit_ref will check ferror */3052 fprintf(lock->lk->tempfile.fp, "ref: %s\n", target);3053 if (commit_ref(lock) < 0)3054 return error("unable to write symref for %s: %s", refname,3055 strerror(errno));3056 return 0;3057}30583059static int files_create_symref(struct ref_store *ref_store,3060 const char *refname, const char *target,3061 const char *logmsg)3062{3063 struct files_ref_store *refs =3064 files_downcast(ref_store, 0, "create_symref");3065 struct strbuf err = STRBUF_INIT;3066 struct ref_lock *lock;3067 int ret;30683069 lock = lock_ref_sha1_basic(refs, refname, NULL,3070 NULL, NULL, REF_NODEREF, NULL,3071 &err);3072 if (!lock) {3073 error("%s", err.buf);3074 strbuf_release(&err);3075 return -1;3076 }30773078 ret = create_symref_locked(lock, refname, target, logmsg);3079 unlock_ref(lock);3080 return ret;3081}30823083int set_worktree_head_symref(const char *gitdir, const char *target)3084{3085 static struct lock_file head_lock;3086 struct ref_lock *lock;3087 struct strbuf head_path = STRBUF_INIT;3088 const char *head_rel;3089 int ret;30903091 strbuf_addf(&head_path, "%s/HEAD", absolute_path(gitdir));3092 if (hold_lock_file_for_update(&head_lock, head_path.buf,3093 LOCK_NO_DEREF) < 0) {3094 struct strbuf err = STRBUF_INIT;3095 unable_to_lock_message(head_path.buf, errno, &err);3096 error("%s", err.buf);3097 strbuf_release(&err);3098 strbuf_release(&head_path);3099 return -1;3100 }31013102 /* head_rel will be "HEAD" for the main tree, "worktrees/wt/HEAD" for3103 linked trees */3104 head_rel = remove_leading_path(head_path.buf,3105 absolute_path(get_git_common_dir()));3106 /* to make use of create_symref_locked(), initialize ref_lock */3107 lock = xcalloc(1, sizeof(struct ref_lock));3108 lock->lk = &head_lock;3109 lock->ref_name = xstrdup(head_rel);31103111 ret = create_symref_locked(lock, head_rel, target, NULL);31123113 unlock_ref(lock); /* will free lock */3114 strbuf_release(&head_path);3115 return ret;3116}31173118static int files_reflog_exists(struct ref_store *ref_store,3119 const char *refname)3120{3121 struct stat st;31223123 /* Check validity (but we don't need the result): */3124 files_downcast(ref_store, 0, "reflog_exists");31253126 return !lstat(git_path("logs/%s", refname), &st) &&3127 S_ISREG(st.st_mode);3128}31293130static int files_delete_reflog(struct ref_store *ref_store,3131 const char *refname)3132{3133 /* Check validity (but we don't need the result): */3134 files_downcast(ref_store, 0, "delete_reflog");31353136 return remove_path(git_path("logs/%s", refname));3137}31383139static int show_one_reflog_ent(struct strbuf *sb, each_reflog_ent_fn fn, void *cb_data)3140{3141 unsigned char osha1[20], nsha1[20];3142 char *email_end, *message;3143 unsigned long timestamp;3144 int tz;31453146 /* old SP new SP name <email> SP time TAB msg LF */3147 if (sb->len < 83 || sb->buf[sb->len - 1] != '\n' ||3148 get_sha1_hex(sb->buf, osha1) || sb->buf[40] != ' ' ||3149 get_sha1_hex(sb->buf + 41, nsha1) || sb->buf[81] != ' ' ||3150 !(email_end = strchr(sb->buf + 82, '>')) ||3151 email_end[1] != ' ' ||3152 !(timestamp = strtoul(email_end + 2, &message, 10)) ||3153 !message || message[0] != ' ' ||3154 (message[1] != '+' && message[1] != '-') ||3155 !isdigit(message[2]) || !isdigit(message[3]) ||3156 !isdigit(message[4]) || !isdigit(message[5]))3157 return 0; /* corrupt? */3158 email_end[1] = '\0';3159 tz = strtol(message + 1, NULL, 10);3160 if (message[6] != '\t')3161 message += 6;3162 else3163 message += 7;3164 return fn(osha1, nsha1, sb->buf + 82, timestamp, tz, message, cb_data);3165}31663167static char *find_beginning_of_line(char *bob, char *scan)3168{3169 while (bob < scan && *(--scan) != '\n')3170 ; /* keep scanning backwards */3171 /*3172 * Return either beginning of the buffer, or LF at the end of3173 * the previous line.3174 */3175 return scan;3176}31773178static int files_for_each_reflog_ent_reverse(struct ref_store *ref_store,3179 const char *refname,3180 each_reflog_ent_fn fn,3181 void *cb_data)3182{3183 struct strbuf sb = STRBUF_INIT;3184 FILE *logfp;3185 long pos;3186 int ret = 0, at_tail = 1;31873188 /* Check validity (but we don't need the result): */3189 files_downcast(ref_store, 0, "for_each_reflog_ent_reverse");31903191 logfp = fopen(git_path("logs/%s", refname), "r");3192 if (!logfp)3193 return -1;31943195 /* Jump to the end */3196 if (fseek(logfp, 0, SEEK_END) < 0)3197 return error("cannot seek back reflog for %s: %s",3198 refname, strerror(errno));3199 pos = ftell(logfp);3200 while (!ret && 0 < pos) {3201 int cnt;3202 size_t nread;3203 char buf[BUFSIZ];3204 char *endp, *scanp;32053206 /* Fill next block from the end */3207 cnt = (sizeof(buf) < pos) ? sizeof(buf) : pos;3208 if (fseek(logfp, pos - cnt, SEEK_SET))3209 return error("cannot seek back reflog for %s: %s",3210 refname, strerror(errno));3211 nread = fread(buf, cnt, 1, logfp);3212 if (nread != 1)3213 return error("cannot read %d bytes from reflog for %s: %s",3214 cnt, refname, strerror(errno));3215 pos -= cnt;32163217 scanp = endp = buf + cnt;3218 if (at_tail && scanp[-1] == '\n')3219 /* Looking at the final LF at the end of the file */3220 scanp--;3221 at_tail = 0;32223223 while (buf < scanp) {3224 /*3225 * terminating LF of the previous line, or the beginning3226 * of the buffer.3227 */3228 char *bp;32293230 bp = find_beginning_of_line(buf, scanp);32313232 if (*bp == '\n') {3233 /*3234 * The newline is the end of the previous line,3235 * so we know we have complete line starting3236 * at (bp + 1). Prefix it onto any prior data3237 * we collected for the line and process it.3238 */3239 strbuf_splice(&sb, 0, 0, bp + 1, endp - (bp + 1));3240 scanp = bp;3241 endp = bp + 1;3242 ret = show_one_reflog_ent(&sb, fn, cb_data);3243 strbuf_reset(&sb);3244 if (ret)3245 break;3246 } else if (!pos) {3247 /*3248 * We are at the start of the buffer, and the3249 * start of the file; there is no previous3250 * line, and we have everything for this one.3251 * Process it, and we can end the loop.3252 */3253 strbuf_splice(&sb, 0, 0, buf, endp - buf);3254 ret = show_one_reflog_ent(&sb, fn, cb_data);3255 strbuf_reset(&sb);3256 break;3257 }32583259 if (bp == buf) {3260 /*3261 * We are at the start of the buffer, and there3262 * is more file to read backwards. Which means3263 * we are in the middle of a line. Note that we3264 * may get here even if *bp was a newline; that3265 * just means we are at the exact end of the3266 * previous line, rather than some spot in the3267 * middle.3268 *3269 * Save away what we have to be combined with3270 * the data from the next read.3271 */3272 strbuf_splice(&sb, 0, 0, buf, endp - buf);3273 break;3274 }3275 }32763277 }3278 if (!ret && sb.len)3279 die("BUG: reverse reflog parser had leftover data");32803281 fclose(logfp);3282 strbuf_release(&sb);3283 return ret;3284}32853286static int files_for_each_reflog_ent(struct ref_store *ref_store,3287 const char *refname,3288 each_reflog_ent_fn fn, void *cb_data)3289{3290 FILE *logfp;3291 struct strbuf sb = STRBUF_INIT;3292 int ret = 0;32933294 /* Check validity (but we don't need the result): */3295 files_downcast(ref_store, 0, "for_each_reflog_ent");32963297 logfp = fopen(git_path("logs/%s", refname), "r");3298 if (!logfp)3299 return -1;33003301 while (!ret && !strbuf_getwholeline(&sb, logfp, '\n'))3302 ret = show_one_reflog_ent(&sb, fn, cb_data);3303 fclose(logfp);3304 strbuf_release(&sb);3305 return ret;3306}33073308struct files_reflog_iterator {3309 struct ref_iterator base;33103311 struct dir_iterator *dir_iterator;3312 struct object_id oid;3313};33143315static int files_reflog_iterator_advance(struct ref_iterator *ref_iterator)3316{3317 struct files_reflog_iterator *iter =3318 (struct files_reflog_iterator *)ref_iterator;3319 struct dir_iterator *diter = iter->dir_iterator;3320 int ok;33213322 while ((ok = dir_iterator_advance(diter)) == ITER_OK) {3323 int flags;33243325 if (!S_ISREG(diter->st.st_mode))3326 continue;3327 if (diter->basename[0] == '.')3328 continue;3329 if (ends_with(diter->basename, ".lock"))3330 continue;33313332 if (read_ref_full(diter->relative_path, 0,3333 iter->oid.hash, &flags)) {3334 error("bad ref for %s", diter->path.buf);3335 continue;3336 }33373338 iter->base.refname = diter->relative_path;3339 iter->base.oid = &iter->oid;3340 iter->base.flags = flags;3341 return ITER_OK;3342 }33433344 iter->dir_iterator = NULL;3345 if (ref_iterator_abort(ref_iterator) == ITER_ERROR)3346 ok = ITER_ERROR;3347 return ok;3348}33493350static int files_reflog_iterator_peel(struct ref_iterator *ref_iterator,3351 struct object_id *peeled)3352{3353 die("BUG: ref_iterator_peel() called for reflog_iterator");3354}33553356static int files_reflog_iterator_abort(struct ref_iterator *ref_iterator)3357{3358 struct files_reflog_iterator *iter =3359 (struct files_reflog_iterator *)ref_iterator;3360 int ok = ITER_DONE;33613362 if (iter->dir_iterator)3363 ok = dir_iterator_abort(iter->dir_iterator);33643365 base_ref_iterator_free(ref_iterator);3366 return ok;3367}33683369static struct ref_iterator_vtable files_reflog_iterator_vtable = {3370 files_reflog_iterator_advance,3371 files_reflog_iterator_peel,3372 files_reflog_iterator_abort3373};33743375static struct ref_iterator *files_reflog_iterator_begin(struct ref_store *ref_store)3376{3377 struct files_reflog_iterator *iter = xcalloc(1, sizeof(*iter));3378 struct ref_iterator *ref_iterator = &iter->base;33793380 /* Check validity (but we don't need the result): */3381 files_downcast(ref_store, 0, "reflog_iterator_begin");33823383 base_ref_iterator_init(ref_iterator, &files_reflog_iterator_vtable);3384 iter->dir_iterator = dir_iterator_begin(git_path("logs"));3385 return ref_iterator;3386}33873388static int ref_update_reject_duplicates(struct string_list *refnames,3389 struct strbuf *err)3390{3391 int i, n = refnames->nr;33923393 assert(err);33943395 for (i = 1; i < n; i++)3396 if (!strcmp(refnames->items[i - 1].string, refnames->items[i].string)) {3397 strbuf_addf(err,3398 "multiple updates for ref '%s' not allowed.",3399 refnames->items[i].string);3400 return 1;3401 }3402 return 0;3403}34043405/*3406 * If update is a direct update of head_ref (the reference pointed to3407 * by HEAD), then add an extra REF_LOG_ONLY update for HEAD.3408 */3409static int split_head_update(struct ref_update *update,3410 struct ref_transaction *transaction,3411 const char *head_ref,3412 struct string_list *affected_refnames,3413 struct strbuf *err)3414{3415 struct string_list_item *item;3416 struct ref_update *new_update;34173418 if ((update->flags & REF_LOG_ONLY) ||3419 (update->flags & REF_ISPRUNING) ||3420 (update->flags & REF_UPDATE_VIA_HEAD))3421 return 0;34223423 if (strcmp(update->refname, head_ref))3424 return 0;34253426 /*3427 * First make sure that HEAD is not already in the3428 * transaction. This insertion is O(N) in the transaction3429 * size, but it happens at most once per transaction.3430 */3431 item = string_list_insert(affected_refnames, "HEAD");3432 if (item->util) {3433 /* An entry already existed */3434 strbuf_addf(err,3435 "multiple updates for 'HEAD' (including one "3436 "via its referent '%s') are not allowed",3437 update->refname);3438 return TRANSACTION_NAME_CONFLICT;3439 }34403441 new_update = ref_transaction_add_update(3442 transaction, "HEAD",3443 update->flags | REF_LOG_ONLY | REF_NODEREF,3444 update->new_sha1, update->old_sha1,3445 update->msg);34463447 item->util = new_update;34483449 return 0;3450}34513452/*3453 * update is for a symref that points at referent and doesn't have3454 * REF_NODEREF set. Split it into two updates:3455 * - The original update, but with REF_LOG_ONLY and REF_NODEREF set3456 * - A new, separate update for the referent reference3457 * Note that the new update will itself be subject to splitting when3458 * the iteration gets to it.3459 */3460static int split_symref_update(struct files_ref_store *refs,3461 struct ref_update *update,3462 const char *referent,3463 struct ref_transaction *transaction,3464 struct string_list *affected_refnames,3465 struct strbuf *err)3466{3467 struct string_list_item *item;3468 struct ref_update *new_update;3469 unsigned int new_flags;34703471 /*3472 * First make sure that referent is not already in the3473 * transaction. This insertion is O(N) in the transaction3474 * size, but it happens at most once per symref in a3475 * transaction.3476 */3477 item = string_list_insert(affected_refnames, referent);3478 if (item->util) {3479 /* An entry already existed */3480 strbuf_addf(err,3481 "multiple updates for '%s' (including one "3482 "via symref '%s') are not allowed",3483 referent, update->refname);3484 return TRANSACTION_NAME_CONFLICT;3485 }34863487 new_flags = update->flags;3488 if (!strcmp(update->refname, "HEAD")) {3489 /*3490 * Record that the new update came via HEAD, so that3491 * when we process it, split_head_update() doesn't try3492 * to add another reflog update for HEAD. Note that3493 * this bit will be propagated if the new_update3494 * itself needs to be split.3495 */3496 new_flags |= REF_UPDATE_VIA_HEAD;3497 }34983499 new_update = ref_transaction_add_update(3500 transaction, referent, new_flags,3501 update->new_sha1, update->old_sha1,3502 update->msg);35033504 new_update->parent_update = update;35053506 /*3507 * Change the symbolic ref update to log only. Also, it3508 * doesn't need to check its old SHA-1 value, as that will be3509 * done when new_update is processed.3510 */3511 update->flags |= REF_LOG_ONLY | REF_NODEREF;3512 update->flags &= ~REF_HAVE_OLD;35133514 item->util = new_update;35153516 return 0;3517}35183519/*3520 * Return the refname under which update was originally requested.3521 */3522static const char *original_update_refname(struct ref_update *update)3523{3524 while (update->parent_update)3525 update = update->parent_update;35263527 return update->refname;3528}35293530/*3531 * Check whether the REF_HAVE_OLD and old_oid values stored in update3532 * are consistent with oid, which is the reference's current value. If3533 * everything is OK, return 0; otherwise, write an error message to3534 * err and return -1.3535 */3536static int check_old_oid(struct ref_update *update, struct object_id *oid,3537 struct strbuf *err)3538{3539 if (!(update->flags & REF_HAVE_OLD) ||3540 !hashcmp(oid->hash, update->old_sha1))3541 return 0;35423543 if (is_null_sha1(update->old_sha1))3544 strbuf_addf(err, "cannot lock ref '%s': "3545 "reference already exists",3546 original_update_refname(update));3547 else if (is_null_oid(oid))3548 strbuf_addf(err, "cannot lock ref '%s': "3549 "reference is missing but expected %s",3550 original_update_refname(update),3551 sha1_to_hex(update->old_sha1));3552 else3553 strbuf_addf(err, "cannot lock ref '%s': "3554 "is at %s but expected %s",3555 original_update_refname(update),3556 oid_to_hex(oid),3557 sha1_to_hex(update->old_sha1));35583559 return -1;3560}35613562/*3563 * Prepare for carrying out update:3564 * - Lock the reference referred to by update.3565 * - Read the reference under lock.3566 * - Check that its old SHA-1 value (if specified) is correct, and in3567 * any case record it in update->lock->old_oid for later use when3568 * writing the reflog.3569 * - If it is a symref update without REF_NODEREF, split it up into a3570 * REF_LOG_ONLY update of the symref and add a separate update for3571 * the referent to transaction.3572 * - If it is an update of head_ref, add a corresponding REF_LOG_ONLY3573 * update of HEAD.3574 */3575static int lock_ref_for_update(struct files_ref_store *refs,3576 struct ref_update *update,3577 struct ref_transaction *transaction,3578 const char *head_ref,3579 struct string_list *affected_refnames,3580 struct strbuf *err)3581{3582 struct strbuf referent = STRBUF_INIT;3583 int mustexist = (update->flags & REF_HAVE_OLD) &&3584 !is_null_sha1(update->old_sha1);3585 int ret;3586 struct ref_lock *lock;35873588 files_assert_main_repository(refs, "lock_ref_for_update");35893590 if ((update->flags & REF_HAVE_NEW) && is_null_sha1(update->new_sha1))3591 update->flags |= REF_DELETING;35923593 if (head_ref) {3594 ret = split_head_update(update, transaction, head_ref,3595 affected_refnames, err);3596 if (ret)3597 return ret;3598 }35993600 ret = lock_raw_ref(refs, update->refname, mustexist,3601 affected_refnames, NULL,3602 &lock, &referent,3603 &update->type, err);3604 if (ret) {3605 char *reason;36063607 reason = strbuf_detach(err, NULL);3608 strbuf_addf(err, "cannot lock ref '%s': %s",3609 original_update_refname(update), reason);3610 free(reason);3611 return ret;3612 }36133614 update->backend_data = lock;36153616 if (update->type & REF_ISSYMREF) {3617 if (update->flags & REF_NODEREF) {3618 /*3619 * We won't be reading the referent as part of3620 * the transaction, so we have to read it here3621 * to record and possibly check old_sha1:3622 */3623 if (read_ref_full(referent.buf, 0,3624 lock->old_oid.hash, NULL)) {3625 if (update->flags & REF_HAVE_OLD) {3626 strbuf_addf(err, "cannot lock ref '%s': "3627 "error reading reference",3628 original_update_refname(update));3629 return -1;3630 }3631 } else if (check_old_oid(update, &lock->old_oid, err)) {3632 return TRANSACTION_GENERIC_ERROR;3633 }3634 } else {3635 /*3636 * Create a new update for the reference this3637 * symref is pointing at. Also, we will record3638 * and verify old_sha1 for this update as part3639 * of processing the split-off update, so we3640 * don't have to do it here.3641 */3642 ret = split_symref_update(refs, update,3643 referent.buf, transaction,3644 affected_refnames, err);3645 if (ret)3646 return ret;3647 }3648 } else {3649 struct ref_update *parent_update;36503651 if (check_old_oid(update, &lock->old_oid, err))3652 return TRANSACTION_GENERIC_ERROR;36533654 /*3655 * If this update is happening indirectly because of a3656 * symref update, record the old SHA-1 in the parent3657 * update:3658 */3659 for (parent_update = update->parent_update;3660 parent_update;3661 parent_update = parent_update->parent_update) {3662 struct ref_lock *parent_lock = parent_update->backend_data;3663 oidcpy(&parent_lock->old_oid, &lock->old_oid);3664 }3665 }36663667 if ((update->flags & REF_HAVE_NEW) &&3668 !(update->flags & REF_DELETING) &&3669 !(update->flags & REF_LOG_ONLY)) {3670 if (!(update->type & REF_ISSYMREF) &&3671 !hashcmp(lock->old_oid.hash, update->new_sha1)) {3672 /*3673 * The reference already has the desired3674 * value, so we don't need to write it.3675 */3676 } else if (write_ref_to_lockfile(lock, update->new_sha1,3677 err)) {3678 char *write_err = strbuf_detach(err, NULL);36793680 /*3681 * The lock was freed upon failure of3682 * write_ref_to_lockfile():3683 */3684 update->backend_data = NULL;3685 strbuf_addf(err,3686 "cannot update ref '%s': %s",3687 update->refname, write_err);3688 free(write_err);3689 return TRANSACTION_GENERIC_ERROR;3690 } else {3691 update->flags |= REF_NEEDS_COMMIT;3692 }3693 }3694 if (!(update->flags & REF_NEEDS_COMMIT)) {3695 /*3696 * We didn't call write_ref_to_lockfile(), so3697 * the lockfile is still open. Close it to3698 * free up the file descriptor:3699 */3700 if (close_ref(lock)) {3701 strbuf_addf(err, "couldn't close '%s.lock'",3702 update->refname);3703 return TRANSACTION_GENERIC_ERROR;3704 }3705 }3706 return 0;3707}37083709static int files_transaction_commit(struct ref_store *ref_store,3710 struct ref_transaction *transaction,3711 struct strbuf *err)3712{3713 struct files_ref_store *refs =3714 files_downcast(ref_store, 0, "ref_transaction_commit");3715 int ret = 0, i;3716 struct string_list refs_to_delete = STRING_LIST_INIT_NODUP;3717 struct string_list_item *ref_to_delete;3718 struct string_list affected_refnames = STRING_LIST_INIT_NODUP;3719 char *head_ref = NULL;3720 int head_type;3721 struct object_id head_oid;37223723 assert(err);37243725 if (transaction->state != REF_TRANSACTION_OPEN)3726 die("BUG: commit called for transaction that is not open");37273728 if (!transaction->nr) {3729 transaction->state = REF_TRANSACTION_CLOSED;3730 return 0;3731 }37323733 /*3734 * Fail if a refname appears more than once in the3735 * transaction. (If we end up splitting up any updates using3736 * split_symref_update() or split_head_update(), those3737 * functions will check that the new updates don't have the3738 * same refname as any existing ones.)3739 */3740 for (i = 0; i < transaction->nr; i++) {3741 struct ref_update *update = transaction->updates[i];3742 struct string_list_item *item =3743 string_list_append(&affected_refnames, update->refname);37443745 /*3746 * We store a pointer to update in item->util, but at3747 * the moment we never use the value of this field3748 * except to check whether it is non-NULL.3749 */3750 item->util = update;3751 }3752 string_list_sort(&affected_refnames);3753 if (ref_update_reject_duplicates(&affected_refnames, err)) {3754 ret = TRANSACTION_GENERIC_ERROR;3755 goto cleanup;3756 }37573758 /*3759 * Special hack: If a branch is updated directly and HEAD3760 * points to it (may happen on the remote side of a push3761 * for example) then logically the HEAD reflog should be3762 * updated too.3763 *3764 * A generic solution would require reverse symref lookups,3765 * but finding all symrefs pointing to a given branch would be3766 * rather costly for this rare event (the direct update of a3767 * branch) to be worth it. So let's cheat and check with HEAD3768 * only, which should cover 99% of all usage scenarios (even3769 * 100% of the default ones).3770 *3771 * So if HEAD is a symbolic reference, then record the name of3772 * the reference that it points to. If we see an update of3773 * head_ref within the transaction, then split_head_update()3774 * arranges for the reflog of HEAD to be updated, too.3775 */3776 head_ref = resolve_refdup("HEAD", RESOLVE_REF_NO_RECURSE,3777 head_oid.hash, &head_type);37783779 if (head_ref && !(head_type & REF_ISSYMREF)) {3780 free(head_ref);3781 head_ref = NULL;3782 }37833784 /*3785 * Acquire all locks, verify old values if provided, check3786 * that new values are valid, and write new values to the3787 * lockfiles, ready to be activated. Only keep one lockfile3788 * open at a time to avoid running out of file descriptors.3789 */3790 for (i = 0; i < transaction->nr; i++) {3791 struct ref_update *update = transaction->updates[i];37923793 ret = lock_ref_for_update(refs, update, transaction,3794 head_ref, &affected_refnames, err);3795 if (ret)3796 goto cleanup;3797 }37983799 /* Perform updates first so live commits remain referenced */3800 for (i = 0; i < transaction->nr; i++) {3801 struct ref_update *update = transaction->updates[i];3802 struct ref_lock *lock = update->backend_data;38033804 if (update->flags & REF_NEEDS_COMMIT ||3805 update->flags & REF_LOG_ONLY) {3806 if (log_ref_write(lock->ref_name, lock->old_oid.hash,3807 update->new_sha1,3808 update->msg, update->flags, err)) {3809 char *old_msg = strbuf_detach(err, NULL);38103811 strbuf_addf(err, "cannot update the ref '%s': %s",3812 lock->ref_name, old_msg);3813 free(old_msg);3814 unlock_ref(lock);3815 update->backend_data = NULL;3816 ret = TRANSACTION_GENERIC_ERROR;3817 goto cleanup;3818 }3819 }3820 if (update->flags & REF_NEEDS_COMMIT) {3821 clear_loose_ref_cache(refs);3822 if (commit_ref(lock)) {3823 strbuf_addf(err, "couldn't set '%s'", lock->ref_name);3824 unlock_ref(lock);3825 update->backend_data = NULL;3826 ret = TRANSACTION_GENERIC_ERROR;3827 goto cleanup;3828 }3829 }3830 }3831 /* Perform deletes now that updates are safely completed */3832 for (i = 0; i < transaction->nr; i++) {3833 struct ref_update *update = transaction->updates[i];3834 struct ref_lock *lock = update->backend_data;38353836 if (update->flags & REF_DELETING &&3837 !(update->flags & REF_LOG_ONLY)) {3838 if (delete_ref_loose(lock, update->type, err)) {3839 ret = TRANSACTION_GENERIC_ERROR;3840 goto cleanup;3841 }38423843 if (!(update->flags & REF_ISPRUNING))3844 string_list_append(&refs_to_delete,3845 lock->ref_name);3846 }3847 }38483849 if (repack_without_refs(refs, &refs_to_delete, err)) {3850 ret = TRANSACTION_GENERIC_ERROR;3851 goto cleanup;3852 }3853 for_each_string_list_item(ref_to_delete, &refs_to_delete)3854 unlink_or_warn(git_path("logs/%s", ref_to_delete->string));3855 clear_loose_ref_cache(refs);38563857cleanup:3858 transaction->state = REF_TRANSACTION_CLOSED;38593860 for (i = 0; i < transaction->nr; i++)3861 if (transaction->updates[i]->backend_data)3862 unlock_ref(transaction->updates[i]->backend_data);3863 string_list_clear(&refs_to_delete, 0);3864 free(head_ref);3865 string_list_clear(&affected_refnames, 0);38663867 return ret;3868}38693870static int ref_present(const char *refname,3871 const struct object_id *oid, int flags, void *cb_data)3872{3873 struct string_list *affected_refnames = cb_data;38743875 return string_list_has_string(affected_refnames, refname);3876}38773878static int files_initial_transaction_commit(struct ref_store *ref_store,3879 struct ref_transaction *transaction,3880 struct strbuf *err)3881{3882 struct files_ref_store *refs =3883 files_downcast(ref_store, 0, "initial_ref_transaction_commit");3884 int ret = 0, i;3885 struct string_list affected_refnames = STRING_LIST_INIT_NODUP;38863887 assert(err);38883889 if (transaction->state != REF_TRANSACTION_OPEN)3890 die("BUG: commit called for transaction that is not open");38913892 /* Fail if a refname appears more than once in the transaction: */3893 for (i = 0; i < transaction->nr; i++)3894 string_list_append(&affected_refnames,3895 transaction->updates[i]->refname);3896 string_list_sort(&affected_refnames);3897 if (ref_update_reject_duplicates(&affected_refnames, err)) {3898 ret = TRANSACTION_GENERIC_ERROR;3899 goto cleanup;3900 }39013902 /*3903 * It's really undefined to call this function in an active3904 * repository or when there are existing references: we are3905 * only locking and changing packed-refs, so (1) any3906 * simultaneous processes might try to change a reference at3907 * the same time we do, and (2) any existing loose versions of3908 * the references that we are setting would have precedence3909 * over our values. But some remote helpers create the remote3910 * "HEAD" and "master" branches before calling this function,3911 * so here we really only check that none of the references3912 * that we are creating already exists.3913 */3914 if (for_each_rawref(ref_present, &affected_refnames))3915 die("BUG: initial ref transaction called with existing refs");39163917 for (i = 0; i < transaction->nr; i++) {3918 struct ref_update *update = transaction->updates[i];39193920 if ((update->flags & REF_HAVE_OLD) &&3921 !is_null_sha1(update->old_sha1))3922 die("BUG: initial ref transaction with old_sha1 set");3923 if (verify_refname_available(update->refname,3924 &affected_refnames, NULL,3925 err)) {3926 ret = TRANSACTION_NAME_CONFLICT;3927 goto cleanup;3928 }3929 }39303931 if (lock_packed_refs(refs, 0)) {3932 strbuf_addf(err, "unable to lock packed-refs file: %s",3933 strerror(errno));3934 ret = TRANSACTION_GENERIC_ERROR;3935 goto cleanup;3936 }39373938 for (i = 0; i < transaction->nr; i++) {3939 struct ref_update *update = transaction->updates[i];39403941 if ((update->flags & REF_HAVE_NEW) &&3942 !is_null_sha1(update->new_sha1))3943 add_packed_ref(refs, update->refname, update->new_sha1);3944 }39453946 if (commit_packed_refs(refs)) {3947 strbuf_addf(err, "unable to commit packed-refs file: %s",3948 strerror(errno));3949 ret = TRANSACTION_GENERIC_ERROR;3950 goto cleanup;3951 }39523953cleanup:3954 transaction->state = REF_TRANSACTION_CLOSED;3955 string_list_clear(&affected_refnames, 0);3956 return ret;3957}39583959struct expire_reflog_cb {3960 unsigned int flags;3961 reflog_expiry_should_prune_fn *should_prune_fn;3962 void *policy_cb;3963 FILE *newlog;3964 unsigned char last_kept_sha1[20];3965};39663967static int expire_reflog_ent(unsigned char *osha1, unsigned char *nsha1,3968 const char *email, unsigned long timestamp, int tz,3969 const char *message, void *cb_data)3970{3971 struct expire_reflog_cb *cb = cb_data;3972 struct expire_reflog_policy_cb *policy_cb = cb->policy_cb;39733974 if (cb->flags & EXPIRE_REFLOGS_REWRITE)3975 osha1 = cb->last_kept_sha1;39763977 if ((*cb->should_prune_fn)(osha1, nsha1, email, timestamp, tz,3978 message, policy_cb)) {3979 if (!cb->newlog)3980 printf("would prune %s", message);3981 else if (cb->flags & EXPIRE_REFLOGS_VERBOSE)3982 printf("prune %s", message);3983 } else {3984 if (cb->newlog) {3985 fprintf(cb->newlog, "%s %s %s %lu %+05d\t%s",3986 sha1_to_hex(osha1), sha1_to_hex(nsha1),3987 email, timestamp, tz, message);3988 hashcpy(cb->last_kept_sha1, nsha1);3989 }3990 if (cb->flags & EXPIRE_REFLOGS_VERBOSE)3991 printf("keep %s", message);3992 }3993 return 0;3994}39953996static int files_reflog_expire(struct ref_store *ref_store,3997 const char *refname, const unsigned char *sha1,3998 unsigned int flags,3999 reflog_expiry_prepare_fn prepare_fn,4000 reflog_expiry_should_prune_fn should_prune_fn,4001 reflog_expiry_cleanup_fn cleanup_fn,4002 void *policy_cb_data)4003{4004 struct files_ref_store *refs =4005 files_downcast(ref_store, 0, "reflog_expire");4006 static struct lock_file reflog_lock;4007 struct expire_reflog_cb cb;4008 struct ref_lock *lock;4009 char *log_file;4010 int status = 0;4011 int type;4012 struct strbuf err = STRBUF_INIT;40134014 memset(&cb, 0, sizeof(cb));4015 cb.flags = flags;4016 cb.policy_cb = policy_cb_data;4017 cb.should_prune_fn = should_prune_fn;40184019 /*4020 * The reflog file is locked by holding the lock on the4021 * reference itself, plus we might need to update the4022 * reference if --updateref was specified:4023 */4024 lock = lock_ref_sha1_basic(refs, refname, sha1,4025 NULL, NULL, REF_NODEREF,4026 &type, &err);4027 if (!lock) {4028 error("cannot lock ref '%s': %s", refname, err.buf);4029 strbuf_release(&err);4030 return -1;4031 }4032 if (!reflog_exists(refname)) {4033 unlock_ref(lock);4034 return 0;4035 }40364037 log_file = git_pathdup("logs/%s", refname);4038 if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {4039 /*4040 * Even though holding $GIT_DIR/logs/$reflog.lock has4041 * no locking implications, we use the lock_file4042 * machinery here anyway because it does a lot of the4043 * work we need, including cleaning up if the program4044 * exits unexpectedly.4045 */4046 if (hold_lock_file_for_update(&reflog_lock, log_file, 0) < 0) {4047 struct strbuf err = STRBUF_INIT;4048 unable_to_lock_message(log_file, errno, &err);4049 error("%s", err.buf);4050 strbuf_release(&err);4051 goto failure;4052 }4053 cb.newlog = fdopen_lock_file(&reflog_lock, "w");4054 if (!cb.newlog) {4055 error("cannot fdopen %s (%s)",4056 get_lock_file_path(&reflog_lock), strerror(errno));4057 goto failure;4058 }4059 }40604061 (*prepare_fn)(refname, sha1, cb.policy_cb);4062 for_each_reflog_ent(refname, expire_reflog_ent, &cb);4063 (*cleanup_fn)(cb.policy_cb);40644065 if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {4066 /*4067 * It doesn't make sense to adjust a reference pointed4068 * to by a symbolic ref based on expiring entries in4069 * the symbolic reference's reflog. Nor can we update4070 * a reference if there are no remaining reflog4071 * entries.4072 */4073 int update = (flags & EXPIRE_REFLOGS_UPDATE_REF) &&4074 !(type & REF_ISSYMREF) &&4075 !is_null_sha1(cb.last_kept_sha1);40764077 if (close_lock_file(&reflog_lock)) {4078 status |= error("couldn't write %s: %s", log_file,4079 strerror(errno));4080 } else if (update &&4081 (write_in_full(get_lock_file_fd(lock->lk),4082 sha1_to_hex(cb.last_kept_sha1), 40) != 40 ||4083 write_str_in_full(get_lock_file_fd(lock->lk), "\n") != 1 ||4084 close_ref(lock) < 0)) {4085 status |= error("couldn't write %s",4086 get_lock_file_path(lock->lk));4087 rollback_lock_file(&reflog_lock);4088 } else if (commit_lock_file(&reflog_lock)) {4089 status |= error("unable to write reflog '%s' (%s)",4090 log_file, strerror(errno));4091 } else if (update && commit_ref(lock)) {4092 status |= error("couldn't set %s", lock->ref_name);4093 }4094 }4095 free(log_file);4096 unlock_ref(lock);4097 return status;40984099 failure:4100 rollback_lock_file(&reflog_lock);4101 free(log_file);4102 unlock_ref(lock);4103 return -1;4104}41054106static int files_init_db(struct ref_store *ref_store, struct strbuf *err)4107{4108 /* Check validity (but we don't need the result): */4109 files_downcast(ref_store, 0, "init_db");41104111 /*4112 * Create .git/refs/{heads,tags}4113 */4114 safe_create_dir(git_path("refs/heads"), 1);4115 safe_create_dir(git_path("refs/tags"), 1);4116 if (get_shared_repository()) {4117 adjust_shared_perm(git_path("refs/heads"));4118 adjust_shared_perm(git_path("refs/tags"));4119 }4120 return 0;4121}41224123struct ref_storage_be refs_be_files = {4124 NULL,4125 "files",4126 files_ref_store_create,4127 files_init_db,4128 files_transaction_commit,4129 files_initial_transaction_commit,41304131 files_pack_refs,4132 files_peel_ref,4133 files_create_symref,4134 files_delete_refs,4135 files_rename_ref,41364137 files_ref_iterator_begin,4138 files_read_raw_ref,4139 files_verify_refname_available,41404141 files_reflog_iterator_begin,4142 files_for_each_reflog_ent,4143 files_for_each_reflog_ent_reverse,4144 files_reflog_exists,4145 files_create_reflog,4146 files_delete_reflog,4147 files_reflog_expire4148};