1#include "../cache.h" 2#include "../refs.h" 3#include "refs-internal.h" 4#include "../iterator.h" 5#include "../dir-iterator.h" 6#include "../lockfile.h" 7#include "../object.h" 8#include "../dir.h" 9 10struct ref_lock { 11 char *ref_name; 12 struct lock_file *lk; 13 struct object_id old_oid; 14}; 15 16struct ref_entry; 17 18/* 19 * Information used (along with the information in ref_entry) to 20 * describe a single cached reference. This data structure only 21 * occurs embedded in a union in struct ref_entry, and only when 22 * (ref_entry->flag & REF_DIR) is zero. 23 */ 24struct ref_value { 25 /* 26 * The name of the object to which this reference resolves 27 * (which may be a tag object). If REF_ISBROKEN, this is 28 * null. If REF_ISSYMREF, then this is the name of the object 29 * referred to by the last reference in the symlink chain. 30 */ 31 struct object_id oid; 32 33 /* 34 * If REF_KNOWS_PEELED, then this field holds the peeled value 35 * of this reference, or null if the reference is known not to 36 * be peelable. See the documentation for peel_ref() for an 37 * exact definition of "peelable". 38 */ 39 struct object_id peeled; 40}; 41 42struct files_ref_store; 43 44/* 45 * Information used (along with the information in ref_entry) to 46 * describe a level in the hierarchy of references. This data 47 * structure only occurs embedded in a union in struct ref_entry, and 48 * only when (ref_entry.flag & REF_DIR) is set. In that case, 49 * (ref_entry.flag & REF_INCOMPLETE) determines whether the references 50 * in the directory have already been read: 51 * 52 * (ref_entry.flag & REF_INCOMPLETE) unset -- a directory of loose 53 * or packed references, already read. 54 * 55 * (ref_entry.flag & REF_INCOMPLETE) set -- a directory of loose 56 * references that hasn't been read yet (nor has any of its 57 * subdirectories). 58 * 59 * Entries within a directory are stored within a growable array of 60 * pointers to ref_entries (entries, nr, alloc). Entries 0 <= i < 61 * sorted are sorted by their component name in strcmp() order and the 62 * remaining entries are unsorted. 63 * 64 * Loose references are read lazily, one directory at a time. When a 65 * directory of loose references is read, then all of the references 66 * in that directory are stored, and REF_INCOMPLETE stubs are created 67 * for any subdirectories, but the subdirectories themselves are not 68 * read. The reading is triggered by get_ref_dir(). 69 */ 70struct ref_dir { 71 int nr, alloc; 72 73 /* 74 * Entries with index 0 <= i < sorted are sorted by name. New 75 * entries are appended to the list unsorted, and are sorted 76 * only when required; thus we avoid the need to sort the list 77 * after the addition of every reference. 78 */ 79 int sorted; 80 81 /* A pointer to the files_ref_store that contains this ref_dir. */ 82 struct files_ref_store *ref_store; 83 84 struct ref_entry **entries; 85}; 86 87/* 88 * Bit values for ref_entry::flag. REF_ISSYMREF=0x01, 89 * REF_ISPACKED=0x02, REF_ISBROKEN=0x04 and REF_BAD_NAME=0x08 are 90 * public values; see refs.h. 91 */ 92 93/* 94 * The field ref_entry->u.value.peeled of this value entry contains 95 * the correct peeled value for the reference, which might be 96 * null_sha1 if the reference is not a tag or if it is broken. 97 */ 98#define REF_KNOWS_PEELED 0x10 99 100/* ref_entry represents a directory of references */ 101#define REF_DIR 0x20 102 103/* 104 * Entry has not yet been read from disk (used only for REF_DIR 105 * entries representing loose references) 106 */ 107#define REF_INCOMPLETE 0x40 108 109/* 110 * A ref_entry represents either a reference or a "subdirectory" of 111 * references. 112 * 113 * Each directory in the reference namespace is represented by a 114 * ref_entry with (flags & REF_DIR) set and containing a subdir member 115 * that holds the entries in that directory that have been read so 116 * far. If (flags & REF_INCOMPLETE) is set, then the directory and 117 * its subdirectories haven't been read yet. REF_INCOMPLETE is only 118 * used for loose reference directories. 119 * 120 * References are represented by a ref_entry with (flags & REF_DIR) 121 * unset and a value member that describes the reference's value. The 122 * flag member is at the ref_entry level, but it is also needed to 123 * interpret the contents of the value field (in other words, a 124 * ref_value object is not very much use without the enclosing 125 * ref_entry). 126 * 127 * Reference names cannot end with slash and directories' names are 128 * always stored with a trailing slash (except for the top-level 129 * directory, which is always denoted by ""). This has two nice 130 * consequences: (1) when the entries in each subdir are sorted 131 * lexicographically by name (as they usually are), the references in 132 * a whole tree can be generated in lexicographic order by traversing 133 * the tree in left-to-right, depth-first order; (2) the names of 134 * references and subdirectories cannot conflict, and therefore the 135 * presence of an empty subdirectory does not block the creation of a 136 * similarly-named reference. (The fact that reference names with the 137 * same leading components can conflict *with each other* is a 138 * separate issue that is regulated by verify_refname_available().) 139 * 140 * Please note that the name field contains the fully-qualified 141 * reference (or subdirectory) name. Space could be saved by only 142 * storing the relative names. But that would require the full names 143 * to be generated on the fly when iterating in do_for_each_ref(), and 144 * would break callback functions, who have always been able to assume 145 * that the name strings that they are passed will not be freed during 146 * the iteration. 147 */ 148struct ref_entry { 149 unsigned char flag; /* ISSYMREF? ISPACKED? */ 150 union { 151 struct ref_value value; /* if not (flags&REF_DIR) */ 152 struct ref_dir subdir; /* if (flags&REF_DIR) */ 153 } u; 154 /* 155 * The full name of the reference (e.g., "refs/heads/master") 156 * or the full name of the directory with a trailing slash 157 * (e.g., "refs/heads/"): 158 */ 159 char name[FLEX_ARRAY]; 160}; 161 162static void read_loose_refs(const char *dirname, struct ref_dir *dir); 163static int search_ref_dir(struct ref_dir *dir, const char *refname, size_t len); 164static struct ref_entry *create_dir_entry(struct files_ref_store *ref_store, 165 const char *dirname, size_t len, 166 int incomplete); 167static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry); 168static int files_log_ref_write(const char *refname, const unsigned char *old_sha1, 169 const unsigned char *new_sha1, const char *msg, 170 int flags, struct strbuf *err); 171 172static struct ref_dir *get_ref_dir(struct ref_entry *entry) 173{ 174 struct ref_dir *dir; 175 assert(entry->flag & REF_DIR); 176 dir = &entry->u.subdir; 177 if (entry->flag & REF_INCOMPLETE) { 178 read_loose_refs(entry->name, dir); 179 180 /* 181 * Manually add refs/bisect, which, being 182 * per-worktree, might not appear in the directory 183 * listing for refs/ in the main repo. 184 */ 185 if (!strcmp(entry->name, "refs/")) { 186 int pos = search_ref_dir(dir, "refs/bisect/", 12); 187 if (pos < 0) { 188 struct ref_entry *child_entry; 189 child_entry = create_dir_entry(dir->ref_store, 190 "refs/bisect/", 191 12, 1); 192 add_entry_to_dir(dir, child_entry); 193 read_loose_refs("refs/bisect", 194 &child_entry->u.subdir); 195 } 196 } 197 entry->flag &= ~REF_INCOMPLETE; 198 } 199 return dir; 200} 201 202static struct ref_entry *create_ref_entry(const char *refname, 203 const unsigned char *sha1, int flag, 204 int check_name) 205{ 206 struct ref_entry *ref; 207 208 if (check_name && 209 check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) 210 die("Reference has invalid format: '%s'", refname); 211 FLEX_ALLOC_STR(ref, name, refname); 212 hashcpy(ref->u.value.oid.hash, sha1); 213 oidclr(&ref->u.value.peeled); 214 ref->flag = flag; 215 return ref; 216} 217 218static void clear_ref_dir(struct ref_dir *dir); 219 220static void free_ref_entry(struct ref_entry *entry) 221{ 222 if (entry->flag & REF_DIR) { 223 /* 224 * Do not use get_ref_dir() here, as that might 225 * trigger the reading of loose refs. 226 */ 227 clear_ref_dir(&entry->u.subdir); 228 } 229 free(entry); 230} 231 232/* 233 * Add a ref_entry to the end of dir (unsorted). Entry is always 234 * stored directly in dir; no recursion into subdirectories is 235 * done. 236 */ 237static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry) 238{ 239 ALLOC_GROW(dir->entries, dir->nr + 1, dir->alloc); 240 dir->entries[dir->nr++] = entry; 241 /* optimize for the case that entries are added in order */ 242 if (dir->nr == 1 || 243 (dir->nr == dir->sorted + 1 && 244 strcmp(dir->entries[dir->nr - 2]->name, 245 dir->entries[dir->nr - 1]->name) < 0)) 246 dir->sorted = dir->nr; 247} 248 249/* 250 * Clear and free all entries in dir, recursively. 251 */ 252static void clear_ref_dir(struct ref_dir *dir) 253{ 254 int i; 255 for (i = 0; i < dir->nr; i++) 256 free_ref_entry(dir->entries[i]); 257 free(dir->entries); 258 dir->sorted = dir->nr = dir->alloc = 0; 259 dir->entries = NULL; 260} 261 262/* 263 * Create a struct ref_entry object for the specified dirname. 264 * dirname is the name of the directory with a trailing slash (e.g., 265 * "refs/heads/") or "" for the top-level directory. 266 */ 267static struct ref_entry *create_dir_entry(struct files_ref_store *ref_store, 268 const char *dirname, size_t len, 269 int incomplete) 270{ 271 struct ref_entry *direntry; 272 FLEX_ALLOC_MEM(direntry, name, dirname, len); 273 direntry->u.subdir.ref_store = ref_store; 274 direntry->flag = REF_DIR | (incomplete ? REF_INCOMPLETE : 0); 275 return direntry; 276} 277 278static int ref_entry_cmp(const void *a, const void *b) 279{ 280 struct ref_entry *one = *(struct ref_entry **)a; 281 struct ref_entry *two = *(struct ref_entry **)b; 282 return strcmp(one->name, two->name); 283} 284 285static void sort_ref_dir(struct ref_dir *dir); 286 287struct string_slice { 288 size_t len; 289 const char *str; 290}; 291 292static int ref_entry_cmp_sslice(const void *key_, const void *ent_) 293{ 294 const struct string_slice *key = key_; 295 const struct ref_entry *ent = *(const struct ref_entry * const *)ent_; 296 int cmp = strncmp(key->str, ent->name, key->len); 297 if (cmp) 298 return cmp; 299 return '\0' - (unsigned char)ent->name[key->len]; 300} 301 302/* 303 * Return the index of the entry with the given refname from the 304 * ref_dir (non-recursively), sorting dir if necessary. Return -1 if 305 * no such entry is found. dir must already be complete. 306 */ 307static int search_ref_dir(struct ref_dir *dir, const char *refname, size_t len) 308{ 309 struct ref_entry **r; 310 struct string_slice key; 311 312 if (refname == NULL || !dir->nr) 313 return -1; 314 315 sort_ref_dir(dir); 316 key.len = len; 317 key.str = refname; 318 r = bsearch(&key, dir->entries, dir->nr, sizeof(*dir->entries), 319 ref_entry_cmp_sslice); 320 321 if (r == NULL) 322 return -1; 323 324 return r - dir->entries; 325} 326 327/* 328 * Search for a directory entry directly within dir (without 329 * recursing). Sort dir if necessary. subdirname must be a directory 330 * name (i.e., end in '/'). If mkdir is set, then create the 331 * directory if it is missing; otherwise, return NULL if the desired 332 * directory cannot be found. dir must already be complete. 333 */ 334static struct ref_dir *search_for_subdir(struct ref_dir *dir, 335 const char *subdirname, size_t len, 336 int mkdir) 337{ 338 int entry_index = search_ref_dir(dir, subdirname, len); 339 struct ref_entry *entry; 340 if (entry_index == -1) { 341 if (!mkdir) 342 return NULL; 343 /* 344 * Since dir is complete, the absence of a subdir 345 * means that the subdir really doesn't exist; 346 * therefore, create an empty record for it but mark 347 * the record complete. 348 */ 349 entry = create_dir_entry(dir->ref_store, subdirname, len, 0); 350 add_entry_to_dir(dir, entry); 351 } else { 352 entry = dir->entries[entry_index]; 353 } 354 return get_ref_dir(entry); 355} 356 357/* 358 * If refname is a reference name, find the ref_dir within the dir 359 * tree that should hold refname. If refname is a directory name 360 * (i.e., ends in '/'), then return that ref_dir itself. dir must 361 * represent the top-level directory and must already be complete. 362 * Sort ref_dirs and recurse into subdirectories as necessary. If 363 * mkdir is set, then create any missing directories; otherwise, 364 * return NULL if the desired directory cannot be found. 365 */ 366static struct ref_dir *find_containing_dir(struct ref_dir *dir, 367 const char *refname, int mkdir) 368{ 369 const char *slash; 370 for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) { 371 size_t dirnamelen = slash - refname + 1; 372 struct ref_dir *subdir; 373 subdir = search_for_subdir(dir, refname, dirnamelen, mkdir); 374 if (!subdir) { 375 dir = NULL; 376 break; 377 } 378 dir = subdir; 379 } 380 381 return dir; 382} 383 384/* 385 * Find the value entry with the given name in dir, sorting ref_dirs 386 * and recursing into subdirectories as necessary. If the name is not 387 * found or it corresponds to a directory entry, return NULL. 388 */ 389static struct ref_entry *find_ref(struct ref_dir *dir, const char *refname) 390{ 391 int entry_index; 392 struct ref_entry *entry; 393 dir = find_containing_dir(dir, refname, 0); 394 if (!dir) 395 return NULL; 396 entry_index = search_ref_dir(dir, refname, strlen(refname)); 397 if (entry_index == -1) 398 return NULL; 399 entry = dir->entries[entry_index]; 400 return (entry->flag & REF_DIR) ? NULL : entry; 401} 402 403/* 404 * Remove the entry with the given name from dir, recursing into 405 * subdirectories as necessary. If refname is the name of a directory 406 * (i.e., ends with '/'), then remove the directory and its contents. 407 * If the removal was successful, return the number of entries 408 * remaining in the directory entry that contained the deleted entry. 409 * If the name was not found, return -1. Please note that this 410 * function only deletes the entry from the cache; it does not delete 411 * it from the filesystem or ensure that other cache entries (which 412 * might be symbolic references to the removed entry) are updated. 413 * Nor does it remove any containing dir entries that might be made 414 * empty by the removal. dir must represent the top-level directory 415 * and must already be complete. 416 */ 417static int remove_entry(struct ref_dir *dir, const char *refname) 418{ 419 int refname_len = strlen(refname); 420 int entry_index; 421 struct ref_entry *entry; 422 int is_dir = refname[refname_len - 1] == '/'; 423 if (is_dir) { 424 /* 425 * refname represents a reference directory. Remove 426 * the trailing slash; otherwise we will get the 427 * directory *representing* refname rather than the 428 * one *containing* it. 429 */ 430 char *dirname = xmemdupz(refname, refname_len - 1); 431 dir = find_containing_dir(dir, dirname, 0); 432 free(dirname); 433 } else { 434 dir = find_containing_dir(dir, refname, 0); 435 } 436 if (!dir) 437 return -1; 438 entry_index = search_ref_dir(dir, refname, refname_len); 439 if (entry_index == -1) 440 return -1; 441 entry = dir->entries[entry_index]; 442 443 memmove(&dir->entries[entry_index], 444 &dir->entries[entry_index + 1], 445 (dir->nr - entry_index - 1) * sizeof(*dir->entries) 446 ); 447 dir->nr--; 448 if (dir->sorted > entry_index) 449 dir->sorted--; 450 free_ref_entry(entry); 451 return dir->nr; 452} 453 454/* 455 * Add a ref_entry to the ref_dir (unsorted), recursing into 456 * subdirectories as necessary. dir must represent the top-level 457 * directory. Return 0 on success. 458 */ 459static int add_ref(struct ref_dir *dir, struct ref_entry *ref) 460{ 461 dir = find_containing_dir(dir, ref->name, 1); 462 if (!dir) 463 return -1; 464 add_entry_to_dir(dir, ref); 465 return 0; 466} 467 468/* 469 * Emit a warning and return true iff ref1 and ref2 have the same name 470 * and the same sha1. Die if they have the same name but different 471 * sha1s. 472 */ 473static int is_dup_ref(const struct ref_entry *ref1, const struct ref_entry *ref2) 474{ 475 if (strcmp(ref1->name, ref2->name)) 476 return 0; 477 478 /* Duplicate name; make sure that they don't conflict: */ 479 480 if ((ref1->flag & REF_DIR) || (ref2->flag & REF_DIR)) 481 /* This is impossible by construction */ 482 die("Reference directory conflict: %s", ref1->name); 483 484 if (oidcmp(&ref1->u.value.oid, &ref2->u.value.oid)) 485 die("Duplicated ref, and SHA1s don't match: %s", ref1->name); 486 487 warning("Duplicated ref: %s", ref1->name); 488 return 1; 489} 490 491/* 492 * Sort the entries in dir non-recursively (if they are not already 493 * sorted) and remove any duplicate entries. 494 */ 495static void sort_ref_dir(struct ref_dir *dir) 496{ 497 int i, j; 498 struct ref_entry *last = NULL; 499 500 /* 501 * This check also prevents passing a zero-length array to qsort(), 502 * which is a problem on some platforms. 503 */ 504 if (dir->sorted == dir->nr) 505 return; 506 507 QSORT(dir->entries, dir->nr, ref_entry_cmp); 508 509 /* Remove any duplicates: */ 510 for (i = 0, j = 0; j < dir->nr; j++) { 511 struct ref_entry *entry = dir->entries[j]; 512 if (last && is_dup_ref(last, entry)) 513 free_ref_entry(entry); 514 else 515 last = dir->entries[i++] = entry; 516 } 517 dir->sorted = dir->nr = i; 518} 519 520/* 521 * Return true if refname, which has the specified oid and flags, can 522 * be resolved to an object in the database. If the referred-to object 523 * does not exist, emit a warning and return false. 524 */ 525static int ref_resolves_to_object(const char *refname, 526 const struct object_id *oid, 527 unsigned int flags) 528{ 529 if (flags & REF_ISBROKEN) 530 return 0; 531 if (!has_sha1_file(oid->hash)) { 532 error("%s does not point to a valid object!", refname); 533 return 0; 534 } 535 return 1; 536} 537 538/* 539 * Return true if the reference described by entry can be resolved to 540 * an object in the database; otherwise, emit a warning and return 541 * false. 542 */ 543static int entry_resolves_to_object(struct ref_entry *entry) 544{ 545 return ref_resolves_to_object(entry->name, 546 &entry->u.value.oid, entry->flag); 547} 548 549typedef int each_ref_entry_fn(struct ref_entry *entry, void *cb_data); 550 551/* 552 * Call fn for each reference in dir that has index in the range 553 * offset <= index < dir->nr. Recurse into subdirectories that are in 554 * that index range, sorting them before iterating. This function 555 * does not sort dir itself; it should be sorted beforehand. fn is 556 * called for all references, including broken ones. 557 */ 558static int do_for_each_entry_in_dir(struct ref_dir *dir, int offset, 559 each_ref_entry_fn fn, void *cb_data) 560{ 561 int i; 562 assert(dir->sorted == dir->nr); 563 for (i = offset; i < dir->nr; i++) { 564 struct ref_entry *entry = dir->entries[i]; 565 int retval; 566 if (entry->flag & REF_DIR) { 567 struct ref_dir *subdir = get_ref_dir(entry); 568 sort_ref_dir(subdir); 569 retval = do_for_each_entry_in_dir(subdir, 0, fn, cb_data); 570 } else { 571 retval = fn(entry, cb_data); 572 } 573 if (retval) 574 return retval; 575 } 576 return 0; 577} 578 579/* 580 * Load all of the refs from the dir into our in-memory cache. The hard work 581 * of loading loose refs is done by get_ref_dir(), so we just need to recurse 582 * through all of the sub-directories. We do not even need to care about 583 * sorting, as traversal order does not matter to us. 584 */ 585static void prime_ref_dir(struct ref_dir *dir) 586{ 587 int i; 588 for (i = 0; i < dir->nr; i++) { 589 struct ref_entry *entry = dir->entries[i]; 590 if (entry->flag & REF_DIR) 591 prime_ref_dir(get_ref_dir(entry)); 592 } 593} 594 595/* 596 * A level in the reference hierarchy that is currently being iterated 597 * through. 598 */ 599struct cache_ref_iterator_level { 600 /* 601 * The ref_dir being iterated over at this level. The ref_dir 602 * is sorted before being stored here. 603 */ 604 struct ref_dir *dir; 605 606 /* 607 * The index of the current entry within dir (which might 608 * itself be a directory). If index == -1, then the iteration 609 * hasn't yet begun. If index == dir->nr, then the iteration 610 * through this level is over. 611 */ 612 int index; 613}; 614 615/* 616 * Represent an iteration through a ref_dir in the memory cache. The 617 * iteration recurses through subdirectories. 618 */ 619struct cache_ref_iterator { 620 struct ref_iterator base; 621 622 /* 623 * The number of levels currently on the stack. This is always 624 * at least 1, because when it becomes zero the iteration is 625 * ended and this struct is freed. 626 */ 627 size_t levels_nr; 628 629 /* The number of levels that have been allocated on the stack */ 630 size_t levels_alloc; 631 632 /* 633 * A stack of levels. levels[0] is the uppermost level that is 634 * being iterated over in this iteration. (This is not 635 * necessary the top level in the references hierarchy. If we 636 * are iterating through a subtree, then levels[0] will hold 637 * the ref_dir for that subtree, and subsequent levels will go 638 * on from there.) 639 */ 640 struct cache_ref_iterator_level *levels; 641}; 642 643static int cache_ref_iterator_advance(struct ref_iterator *ref_iterator) 644{ 645 struct cache_ref_iterator *iter = 646 (struct cache_ref_iterator *)ref_iterator; 647 648 while (1) { 649 struct cache_ref_iterator_level *level = 650 &iter->levels[iter->levels_nr - 1]; 651 struct ref_dir *dir = level->dir; 652 struct ref_entry *entry; 653 654 if (level->index == -1) 655 sort_ref_dir(dir); 656 657 if (++level->index == level->dir->nr) { 658 /* This level is exhausted; pop up a level */ 659 if (--iter->levels_nr == 0) 660 return ref_iterator_abort(ref_iterator); 661 662 continue; 663 } 664 665 entry = dir->entries[level->index]; 666 667 if (entry->flag & REF_DIR) { 668 /* push down a level */ 669 ALLOC_GROW(iter->levels, iter->levels_nr + 1, 670 iter->levels_alloc); 671 672 level = &iter->levels[iter->levels_nr++]; 673 level->dir = get_ref_dir(entry); 674 level->index = -1; 675 } else { 676 iter->base.refname = entry->name; 677 iter->base.oid = &entry->u.value.oid; 678 iter->base.flags = entry->flag; 679 return ITER_OK; 680 } 681 } 682} 683 684static enum peel_status peel_entry(struct ref_entry *entry, int repeel); 685 686static int cache_ref_iterator_peel(struct ref_iterator *ref_iterator, 687 struct object_id *peeled) 688{ 689 struct cache_ref_iterator *iter = 690 (struct cache_ref_iterator *)ref_iterator; 691 struct cache_ref_iterator_level *level; 692 struct ref_entry *entry; 693 694 level = &iter->levels[iter->levels_nr - 1]; 695 696 if (level->index == -1) 697 die("BUG: peel called before advance for cache iterator"); 698 699 entry = level->dir->entries[level->index]; 700 701 if (peel_entry(entry, 0)) 702 return -1; 703 oidcpy(peeled, &entry->u.value.peeled); 704 return 0; 705} 706 707static int cache_ref_iterator_abort(struct ref_iterator *ref_iterator) 708{ 709 struct cache_ref_iterator *iter = 710 (struct cache_ref_iterator *)ref_iterator; 711 712 free(iter->levels); 713 base_ref_iterator_free(ref_iterator); 714 return ITER_DONE; 715} 716 717static struct ref_iterator_vtable cache_ref_iterator_vtable = { 718 cache_ref_iterator_advance, 719 cache_ref_iterator_peel, 720 cache_ref_iterator_abort 721}; 722 723static struct ref_iterator *cache_ref_iterator_begin(struct ref_dir *dir) 724{ 725 struct cache_ref_iterator *iter; 726 struct ref_iterator *ref_iterator; 727 struct cache_ref_iterator_level *level; 728 729 iter = xcalloc(1, sizeof(*iter)); 730 ref_iterator = &iter->base; 731 base_ref_iterator_init(ref_iterator, &cache_ref_iterator_vtable); 732 ALLOC_GROW(iter->levels, 10, iter->levels_alloc); 733 734 iter->levels_nr = 1; 735 level = &iter->levels[0]; 736 level->index = -1; 737 level->dir = dir; 738 739 return ref_iterator; 740} 741 742struct nonmatching_ref_data { 743 const struct string_list *skip; 744 const char *conflicting_refname; 745}; 746 747static int nonmatching_ref_fn(struct ref_entry *entry, void *vdata) 748{ 749 struct nonmatching_ref_data *data = vdata; 750 751 if (data->skip && string_list_has_string(data->skip, entry->name)) 752 return 0; 753 754 data->conflicting_refname = entry->name; 755 return 1; 756} 757 758/* 759 * Return 0 if a reference named refname could be created without 760 * conflicting with the name of an existing reference in dir. 761 * See verify_refname_available for more information. 762 */ 763static int verify_refname_available_dir(const char *refname, 764 const struct string_list *extras, 765 const struct string_list *skip, 766 struct ref_dir *dir, 767 struct strbuf *err) 768{ 769 const char *slash; 770 const char *extra_refname; 771 int pos; 772 struct strbuf dirname = STRBUF_INIT; 773 int ret = -1; 774 775 /* 776 * For the sake of comments in this function, suppose that 777 * refname is "refs/foo/bar". 778 */ 779 780 assert(err); 781 782 strbuf_grow(&dirname, strlen(refname) + 1); 783 for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) { 784 /* Expand dirname to the new prefix, not including the trailing slash: */ 785 strbuf_add(&dirname, refname + dirname.len, slash - refname - dirname.len); 786 787 /* 788 * We are still at a leading dir of the refname (e.g., 789 * "refs/foo"; if there is a reference with that name, 790 * it is a conflict, *unless* it is in skip. 791 */ 792 if (dir) { 793 pos = search_ref_dir(dir, dirname.buf, dirname.len); 794 if (pos >= 0 && 795 (!skip || !string_list_has_string(skip, dirname.buf))) { 796 /* 797 * We found a reference whose name is 798 * a proper prefix of refname; e.g., 799 * "refs/foo", and is not in skip. 800 */ 801 strbuf_addf(err, "'%s' exists; cannot create '%s'", 802 dirname.buf, refname); 803 goto cleanup; 804 } 805 } 806 807 if (extras && string_list_has_string(extras, dirname.buf) && 808 (!skip || !string_list_has_string(skip, dirname.buf))) { 809 strbuf_addf(err, "cannot process '%s' and '%s' at the same time", 810 refname, dirname.buf); 811 goto cleanup; 812 } 813 814 /* 815 * Otherwise, we can try to continue our search with 816 * the next component. So try to look up the 817 * directory, e.g., "refs/foo/". If we come up empty, 818 * we know there is nothing under this whole prefix, 819 * but even in that case we still have to continue the 820 * search for conflicts with extras. 821 */ 822 strbuf_addch(&dirname, '/'); 823 if (dir) { 824 pos = search_ref_dir(dir, dirname.buf, dirname.len); 825 if (pos < 0) { 826 /* 827 * There was no directory "refs/foo/", 828 * so there is nothing under this 829 * whole prefix. So there is no need 830 * to continue looking for conflicting 831 * references. But we need to continue 832 * looking for conflicting extras. 833 */ 834 dir = NULL; 835 } else { 836 dir = get_ref_dir(dir->entries[pos]); 837 } 838 } 839 } 840 841 /* 842 * We are at the leaf of our refname (e.g., "refs/foo/bar"). 843 * There is no point in searching for a reference with that 844 * name, because a refname isn't considered to conflict with 845 * itself. But we still need to check for references whose 846 * names are in the "refs/foo/bar/" namespace, because they 847 * *do* conflict. 848 */ 849 strbuf_addstr(&dirname, refname + dirname.len); 850 strbuf_addch(&dirname, '/'); 851 852 if (dir) { 853 pos = search_ref_dir(dir, dirname.buf, dirname.len); 854 855 if (pos >= 0) { 856 /* 857 * We found a directory named "$refname/" 858 * (e.g., "refs/foo/bar/"). It is a problem 859 * iff it contains any ref that is not in 860 * "skip". 861 */ 862 struct nonmatching_ref_data data; 863 864 data.skip = skip; 865 data.conflicting_refname = NULL; 866 dir = get_ref_dir(dir->entries[pos]); 867 sort_ref_dir(dir); 868 if (do_for_each_entry_in_dir(dir, 0, nonmatching_ref_fn, &data)) { 869 strbuf_addf(err, "'%s' exists; cannot create '%s'", 870 data.conflicting_refname, refname); 871 goto cleanup; 872 } 873 } 874 } 875 876 extra_refname = find_descendant_ref(dirname.buf, extras, skip); 877 if (extra_refname) 878 strbuf_addf(err, "cannot process '%s' and '%s' at the same time", 879 refname, extra_refname); 880 else 881 ret = 0; 882 883cleanup: 884 strbuf_release(&dirname); 885 return ret; 886} 887 888struct packed_ref_cache { 889 struct ref_entry *root; 890 891 /* 892 * Count of references to the data structure in this instance, 893 * including the pointer from files_ref_store::packed if any. 894 * The data will not be freed as long as the reference count 895 * is nonzero. 896 */ 897 unsigned int referrers; 898 899 /* 900 * Iff the packed-refs file associated with this instance is 901 * currently locked for writing, this points at the associated 902 * lock (which is owned by somebody else). The referrer count 903 * is also incremented when the file is locked and decremented 904 * when it is unlocked. 905 */ 906 struct lock_file *lock; 907 908 /* The metadata from when this packed-refs cache was read */ 909 struct stat_validity validity; 910}; 911 912/* 913 * Future: need to be in "struct repository" 914 * when doing a full libification. 915 */ 916struct files_ref_store { 917 struct ref_store base; 918 919 /* 920 * The name of the submodule represented by this object, or 921 * NULL if it represents the main repository's reference 922 * store: 923 */ 924 const char *submodule; 925 926 struct ref_entry *loose; 927 struct packed_ref_cache *packed; 928}; 929 930/* Lock used for the main packed-refs file: */ 931static struct lock_file packlock; 932 933/* 934 * Increment the reference count of *packed_refs. 935 */ 936static void acquire_packed_ref_cache(struct packed_ref_cache *packed_refs) 937{ 938 packed_refs->referrers++; 939} 940 941/* 942 * Decrease the reference count of *packed_refs. If it goes to zero, 943 * free *packed_refs and return true; otherwise return false. 944 */ 945static int release_packed_ref_cache(struct packed_ref_cache *packed_refs) 946{ 947 if (!--packed_refs->referrers) { 948 free_ref_entry(packed_refs->root); 949 stat_validity_clear(&packed_refs->validity); 950 free(packed_refs); 951 return 1; 952 } else { 953 return 0; 954 } 955} 956 957static void clear_packed_ref_cache(struct files_ref_store *refs) 958{ 959 if (refs->packed) { 960 struct packed_ref_cache *packed_refs = refs->packed; 961 962 if (packed_refs->lock) 963 die("internal error: packed-ref cache cleared while locked"); 964 refs->packed = NULL; 965 release_packed_ref_cache(packed_refs); 966 } 967} 968 969static void clear_loose_ref_cache(struct files_ref_store *refs) 970{ 971 if (refs->loose) { 972 free_ref_entry(refs->loose); 973 refs->loose = NULL; 974 } 975} 976 977/* 978 * Create a new submodule ref cache and add it to the internal 979 * set of caches. 980 */ 981static struct ref_store *files_ref_store_create(const char *submodule) 982{ 983 struct files_ref_store *refs = xcalloc(1, sizeof(*refs)); 984 struct ref_store *ref_store = (struct ref_store *)refs; 985 986 base_ref_store_init(ref_store, &refs_be_files); 987 988 refs->submodule = xstrdup_or_null(submodule); 989 990 return ref_store; 991} 992 993/* 994 * Die if refs is for a submodule (i.e., not for the main repository). 995 * caller is used in any necessary error messages. 996 */ 997static void files_assert_main_repository(struct files_ref_store *refs, 998 const char *caller) 999{1000 if (refs->submodule)1001 die("BUG: %s called for a submodule", caller);1002}10031004/*1005 * Downcast ref_store to files_ref_store. Die if ref_store is not a1006 * files_ref_store. If submodule_allowed is not true, then also die if1007 * files_ref_store is for a submodule (i.e., not for the main1008 * repository). caller is used in any necessary error messages.1009 */1010static struct files_ref_store *files_downcast(1011 struct ref_store *ref_store, int submodule_allowed,1012 const char *caller)1013{1014 struct files_ref_store *refs;10151016 if (ref_store->be != &refs_be_files)1017 die("BUG: ref_store is type \"%s\" not \"files\" in %s",1018 ref_store->be->name, caller);10191020 refs = (struct files_ref_store *)ref_store;10211022 if (!submodule_allowed)1023 files_assert_main_repository(refs, caller);10241025 return refs;1026}10271028/* The length of a peeled reference line in packed-refs, including EOL: */1029#define PEELED_LINE_LENGTH 4210301031/*1032 * The packed-refs header line that we write out. Perhaps other1033 * traits will be added later. The trailing space is required.1034 */1035static const char PACKED_REFS_HEADER[] =1036 "# pack-refs with: peeled fully-peeled \n";10371038/*1039 * Parse one line from a packed-refs file. Write the SHA1 to sha1.1040 * Return a pointer to the refname within the line (null-terminated),1041 * or NULL if there was a problem.1042 */1043static const char *parse_ref_line(struct strbuf *line, unsigned char *sha1)1044{1045 const char *ref;10461047 /*1048 * 42: the answer to everything.1049 *1050 * In this case, it happens to be the answer to1051 * 40 (length of sha1 hex representation)1052 * +1 (space in between hex and name)1053 * +1 (newline at the end of the line)1054 */1055 if (line->len <= 42)1056 return NULL;10571058 if (get_sha1_hex(line->buf, sha1) < 0)1059 return NULL;1060 if (!isspace(line->buf[40]))1061 return NULL;10621063 ref = line->buf + 41;1064 if (isspace(*ref))1065 return NULL;10661067 if (line->buf[line->len - 1] != '\n')1068 return NULL;1069 line->buf[--line->len] = 0;10701071 return ref;1072}10731074/*1075 * Read f, which is a packed-refs file, into dir.1076 *1077 * A comment line of the form "# pack-refs with: " may contain zero or1078 * more traits. We interpret the traits as follows:1079 *1080 * No traits:1081 *1082 * Probably no references are peeled. But if the file contains a1083 * peeled value for a reference, we will use it.1084 *1085 * peeled:1086 *1087 * References under "refs/tags/", if they *can* be peeled, *are*1088 * peeled in this file. References outside of "refs/tags/" are1089 * probably not peeled even if they could have been, but if we find1090 * a peeled value for such a reference we will use it.1091 *1092 * fully-peeled:1093 *1094 * All references in the file that can be peeled are peeled.1095 * Inversely (and this is more important), any references in the1096 * file for which no peeled value is recorded is not peelable. This1097 * trait should typically be written alongside "peeled" for1098 * compatibility with older clients, but we do not require it1099 * (i.e., "peeled" is a no-op if "fully-peeled" is set).1100 */1101static void read_packed_refs(FILE *f, struct ref_dir *dir)1102{1103 struct ref_entry *last = NULL;1104 struct strbuf line = STRBUF_INIT;1105 enum { PEELED_NONE, PEELED_TAGS, PEELED_FULLY } peeled = PEELED_NONE;11061107 while (strbuf_getwholeline(&line, f, '\n') != EOF) {1108 unsigned char sha1[20];1109 const char *refname;1110 const char *traits;11111112 if (skip_prefix(line.buf, "# pack-refs with:", &traits)) {1113 if (strstr(traits, " fully-peeled "))1114 peeled = PEELED_FULLY;1115 else if (strstr(traits, " peeled "))1116 peeled = PEELED_TAGS;1117 /* perhaps other traits later as well */1118 continue;1119 }11201121 refname = parse_ref_line(&line, sha1);1122 if (refname) {1123 int flag = REF_ISPACKED;11241125 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {1126 if (!refname_is_safe(refname))1127 die("packed refname is dangerous: %s", refname);1128 hashclr(sha1);1129 flag |= REF_BAD_NAME | REF_ISBROKEN;1130 }1131 last = create_ref_entry(refname, sha1, flag, 0);1132 if (peeled == PEELED_FULLY ||1133 (peeled == PEELED_TAGS && starts_with(refname, "refs/tags/")))1134 last->flag |= REF_KNOWS_PEELED;1135 add_ref(dir, last);1136 continue;1137 }1138 if (last &&1139 line.buf[0] == '^' &&1140 line.len == PEELED_LINE_LENGTH &&1141 line.buf[PEELED_LINE_LENGTH - 1] == '\n' &&1142 !get_sha1_hex(line.buf + 1, sha1)) {1143 hashcpy(last->u.value.peeled.hash, sha1);1144 /*1145 * Regardless of what the file header said,1146 * we definitely know the value of *this*1147 * reference:1148 */1149 last->flag |= REF_KNOWS_PEELED;1150 }1151 }11521153 strbuf_release(&line);1154}11551156/*1157 * Get the packed_ref_cache for the specified files_ref_store,1158 * creating it if necessary.1159 */1160static struct packed_ref_cache *get_packed_ref_cache(struct files_ref_store *refs)1161{1162 char *packed_refs_file;11631164 if (refs->submodule)1165 packed_refs_file = git_pathdup_submodule(refs->submodule,1166 "packed-refs");1167 else1168 packed_refs_file = git_pathdup("packed-refs");11691170 if (refs->packed &&1171 !stat_validity_check(&refs->packed->validity, packed_refs_file))1172 clear_packed_ref_cache(refs);11731174 if (!refs->packed) {1175 FILE *f;11761177 refs->packed = xcalloc(1, sizeof(*refs->packed));1178 acquire_packed_ref_cache(refs->packed);1179 refs->packed->root = create_dir_entry(refs, "", 0, 0);1180 f = fopen(packed_refs_file, "r");1181 if (f) {1182 stat_validity_update(&refs->packed->validity, fileno(f));1183 read_packed_refs(f, get_ref_dir(refs->packed->root));1184 fclose(f);1185 }1186 }1187 free(packed_refs_file);1188 return refs->packed;1189}11901191static struct ref_dir *get_packed_ref_dir(struct packed_ref_cache *packed_ref_cache)1192{1193 return get_ref_dir(packed_ref_cache->root);1194}11951196static struct ref_dir *get_packed_refs(struct files_ref_store *refs)1197{1198 return get_packed_ref_dir(get_packed_ref_cache(refs));1199}12001201/*1202 * Add a reference to the in-memory packed reference cache. This may1203 * only be called while the packed-refs file is locked (see1204 * lock_packed_refs()). To actually write the packed-refs file, call1205 * commit_packed_refs().1206 */1207static void add_packed_ref(struct files_ref_store *refs,1208 const char *refname, const unsigned char *sha1)1209{1210 struct packed_ref_cache *packed_ref_cache = get_packed_ref_cache(refs);12111212 if (!packed_ref_cache->lock)1213 die("internal error: packed refs not locked");1214 add_ref(get_packed_ref_dir(packed_ref_cache),1215 create_ref_entry(refname, sha1, REF_ISPACKED, 1));1216}12171218/*1219 * Read the loose references from the namespace dirname into dir1220 * (without recursing). dirname must end with '/'. dir must be the1221 * directory entry corresponding to dirname.1222 */1223static void read_loose_refs(const char *dirname, struct ref_dir *dir)1224{1225 struct files_ref_store *refs = dir->ref_store;1226 DIR *d;1227 struct dirent *de;1228 int dirnamelen = strlen(dirname);1229 struct strbuf refname;1230 struct strbuf path = STRBUF_INIT;1231 size_t path_baselen;1232 int err = 0;12331234 if (refs->submodule)1235 err = strbuf_git_path_submodule(&path, refs->submodule, "%s", dirname);1236 else1237 strbuf_git_path(&path, "%s", dirname);1238 path_baselen = path.len;12391240 if (err) {1241 strbuf_release(&path);1242 return;1243 }12441245 d = opendir(path.buf);1246 if (!d) {1247 strbuf_release(&path);1248 return;1249 }12501251 strbuf_init(&refname, dirnamelen + 257);1252 strbuf_add(&refname, dirname, dirnamelen);12531254 while ((de = readdir(d)) != NULL) {1255 unsigned char sha1[20];1256 struct stat st;1257 int flag;12581259 if (de->d_name[0] == '.')1260 continue;1261 if (ends_with(de->d_name, ".lock"))1262 continue;1263 strbuf_addstr(&refname, de->d_name);1264 strbuf_addstr(&path, de->d_name);1265 if (stat(path.buf, &st) < 0) {1266 ; /* silently ignore */1267 } else if (S_ISDIR(st.st_mode)) {1268 strbuf_addch(&refname, '/');1269 add_entry_to_dir(dir,1270 create_dir_entry(refs, refname.buf,1271 refname.len, 1));1272 } else {1273 if (!resolve_ref_recursively(&refs->base,1274 refname.buf,1275 RESOLVE_REF_READING,1276 sha1, &flag)) {1277 hashclr(sha1);1278 flag |= REF_ISBROKEN;1279 } else if (is_null_sha1(sha1)) {1280 /*1281 * It is so astronomically unlikely1282 * that NULL_SHA1 is the SHA-1 of an1283 * actual object that we consider its1284 * appearance in a loose reference1285 * file to be repo corruption1286 * (probably due to a software bug).1287 */1288 flag |= REF_ISBROKEN;1289 }12901291 if (check_refname_format(refname.buf,1292 REFNAME_ALLOW_ONELEVEL)) {1293 if (!refname_is_safe(refname.buf))1294 die("loose refname is dangerous: %s", refname.buf);1295 hashclr(sha1);1296 flag |= REF_BAD_NAME | REF_ISBROKEN;1297 }1298 add_entry_to_dir(dir,1299 create_ref_entry(refname.buf, sha1, flag, 0));1300 }1301 strbuf_setlen(&refname, dirnamelen);1302 strbuf_setlen(&path, path_baselen);1303 }1304 strbuf_release(&refname);1305 strbuf_release(&path);1306 closedir(d);1307}13081309static struct ref_dir *get_loose_refs(struct files_ref_store *refs)1310{1311 if (!refs->loose) {1312 /*1313 * Mark the top-level directory complete because we1314 * are about to read the only subdirectory that can1315 * hold references:1316 */1317 refs->loose = create_dir_entry(refs, "", 0, 0);1318 /*1319 * Create an incomplete entry for "refs/":1320 */1321 add_entry_to_dir(get_ref_dir(refs->loose),1322 create_dir_entry(refs, "refs/", 5, 1));1323 }1324 return get_ref_dir(refs->loose);1325}13261327/*1328 * Return the ref_entry for the given refname from the packed1329 * references. If it does not exist, return NULL.1330 */1331static struct ref_entry *get_packed_ref(struct files_ref_store *refs,1332 const char *refname)1333{1334 return find_ref(get_packed_refs(refs), refname);1335}13361337/*1338 * A loose ref file doesn't exist; check for a packed ref.1339 */1340static int resolve_packed_ref(struct files_ref_store *refs,1341 const char *refname,1342 unsigned char *sha1, unsigned int *flags)1343{1344 struct ref_entry *entry;13451346 /*1347 * The loose reference file does not exist; check for a packed1348 * reference.1349 */1350 entry = get_packed_ref(refs, refname);1351 if (entry) {1352 hashcpy(sha1, entry->u.value.oid.hash);1353 *flags |= REF_ISPACKED;1354 return 0;1355 }1356 /* refname is not a packed reference. */1357 return -1;1358}13591360static int files_read_raw_ref(struct ref_store *ref_store,1361 const char *refname, unsigned char *sha1,1362 struct strbuf *referent, unsigned int *type)1363{1364 struct files_ref_store *refs =1365 files_downcast(ref_store, 1, "read_raw_ref");1366 struct strbuf sb_contents = STRBUF_INIT;1367 struct strbuf sb_path = STRBUF_INIT;1368 const char *path;1369 const char *buf;1370 struct stat st;1371 int fd;1372 int ret = -1;1373 int save_errno;1374 int remaining_retries = 3;13751376 *type = 0;1377 strbuf_reset(&sb_path);13781379 if (refs->submodule)1380 strbuf_git_path_submodule(&sb_path, refs->submodule, "%s", refname);1381 else1382 strbuf_git_path(&sb_path, "%s", refname);13831384 path = sb_path.buf;13851386stat_ref:1387 /*1388 * We might have to loop back here to avoid a race1389 * condition: first we lstat() the file, then we try1390 * to read it as a link or as a file. But if somebody1391 * changes the type of the file (file <-> directory1392 * <-> symlink) between the lstat() and reading, then1393 * we don't want to report that as an error but rather1394 * try again starting with the lstat().1395 *1396 * We'll keep a count of the retries, though, just to avoid1397 * any confusing situation sending us into an infinite loop.1398 */13991400 if (remaining_retries-- <= 0)1401 goto out;14021403 if (lstat(path, &st) < 0) {1404 if (errno != ENOENT)1405 goto out;1406 if (resolve_packed_ref(refs, refname, sha1, type)) {1407 errno = ENOENT;1408 goto out;1409 }1410 ret = 0;1411 goto out;1412 }14131414 /* Follow "normalized" - ie "refs/.." symlinks by hand */1415 if (S_ISLNK(st.st_mode)) {1416 strbuf_reset(&sb_contents);1417 if (strbuf_readlink(&sb_contents, path, 0) < 0) {1418 if (errno == ENOENT || errno == EINVAL)1419 /* inconsistent with lstat; retry */1420 goto stat_ref;1421 else1422 goto out;1423 }1424 if (starts_with(sb_contents.buf, "refs/") &&1425 !check_refname_format(sb_contents.buf, 0)) {1426 strbuf_swap(&sb_contents, referent);1427 *type |= REF_ISSYMREF;1428 ret = 0;1429 goto out;1430 }1431 /*1432 * It doesn't look like a refname; fall through to just1433 * treating it like a non-symlink, and reading whatever it1434 * points to.1435 */1436 }14371438 /* Is it a directory? */1439 if (S_ISDIR(st.st_mode)) {1440 /*1441 * Even though there is a directory where the loose1442 * ref is supposed to be, there could still be a1443 * packed ref:1444 */1445 if (resolve_packed_ref(refs, refname, sha1, type)) {1446 errno = EISDIR;1447 goto out;1448 }1449 ret = 0;1450 goto out;1451 }14521453 /*1454 * Anything else, just open it and try to use it as1455 * a ref1456 */1457 fd = open(path, O_RDONLY);1458 if (fd < 0) {1459 if (errno == ENOENT && !S_ISLNK(st.st_mode))1460 /* inconsistent with lstat; retry */1461 goto stat_ref;1462 else1463 goto out;1464 }1465 strbuf_reset(&sb_contents);1466 if (strbuf_read(&sb_contents, fd, 256) < 0) {1467 int save_errno = errno;1468 close(fd);1469 errno = save_errno;1470 goto out;1471 }1472 close(fd);1473 strbuf_rtrim(&sb_contents);1474 buf = sb_contents.buf;1475 if (starts_with(buf, "ref:")) {1476 buf += 4;1477 while (isspace(*buf))1478 buf++;14791480 strbuf_reset(referent);1481 strbuf_addstr(referent, buf);1482 *type |= REF_ISSYMREF;1483 ret = 0;1484 goto out;1485 }14861487 /*1488 * Please note that FETCH_HEAD has additional1489 * data after the sha.1490 */1491 if (get_sha1_hex(buf, sha1) ||1492 (buf[40] != '\0' && !isspace(buf[40]))) {1493 *type |= REF_ISBROKEN;1494 errno = EINVAL;1495 goto out;1496 }14971498 ret = 0;14991500out:1501 save_errno = errno;1502 strbuf_release(&sb_path);1503 strbuf_release(&sb_contents);1504 errno = save_errno;1505 return ret;1506}15071508static void unlock_ref(struct ref_lock *lock)1509{1510 /* Do not free lock->lk -- atexit() still looks at them */1511 if (lock->lk)1512 rollback_lock_file(lock->lk);1513 free(lock->ref_name);1514 free(lock);1515}15161517/*1518 * Lock refname, without following symrefs, and set *lock_p to point1519 * at a newly-allocated lock object. Fill in lock->old_oid, referent,1520 * and type similarly to read_raw_ref().1521 *1522 * The caller must verify that refname is a "safe" reference name (in1523 * the sense of refname_is_safe()) before calling this function.1524 *1525 * If the reference doesn't already exist, verify that refname doesn't1526 * have a D/F conflict with any existing references. extras and skip1527 * are passed to verify_refname_available_dir() for this check.1528 *1529 * If mustexist is not set and the reference is not found or is1530 * broken, lock the reference anyway but clear sha1.1531 *1532 * Return 0 on success. On failure, write an error message to err and1533 * return TRANSACTION_NAME_CONFLICT or TRANSACTION_GENERIC_ERROR.1534 *1535 * Implementation note: This function is basically1536 *1537 * lock reference1538 * read_raw_ref()1539 *1540 * but it includes a lot more code to1541 * - Deal with possible races with other processes1542 * - Avoid calling verify_refname_available_dir() when it can be1543 * avoided, namely if we were successfully able to read the ref1544 * - Generate informative error messages in the case of failure1545 */1546static int lock_raw_ref(struct files_ref_store *refs,1547 const char *refname, int mustexist,1548 const struct string_list *extras,1549 const struct string_list *skip,1550 struct ref_lock **lock_p,1551 struct strbuf *referent,1552 unsigned int *type,1553 struct strbuf *err)1554{1555 struct ref_lock *lock;1556 struct strbuf ref_file = STRBUF_INIT;1557 int attempts_remaining = 3;1558 int ret = TRANSACTION_GENERIC_ERROR;15591560 assert(err);1561 files_assert_main_repository(refs, "lock_raw_ref");15621563 *type = 0;15641565 /* First lock the file so it can't change out from under us. */15661567 *lock_p = lock = xcalloc(1, sizeof(*lock));15681569 lock->ref_name = xstrdup(refname);1570 strbuf_git_path(&ref_file, "%s", refname);15711572retry:1573 switch (safe_create_leading_directories(ref_file.buf)) {1574 case SCLD_OK:1575 break; /* success */1576 case SCLD_EXISTS:1577 /*1578 * Suppose refname is "refs/foo/bar". We just failed1579 * to create the containing directory, "refs/foo",1580 * because there was a non-directory in the way. This1581 * indicates a D/F conflict, probably because of1582 * another reference such as "refs/foo". There is no1583 * reason to expect this error to be transitory.1584 */1585 if (verify_refname_available(refname, extras, skip, err)) {1586 if (mustexist) {1587 /*1588 * To the user the relevant error is1589 * that the "mustexist" reference is1590 * missing:1591 */1592 strbuf_reset(err);1593 strbuf_addf(err, "unable to resolve reference '%s'",1594 refname);1595 } else {1596 /*1597 * The error message set by1598 * verify_refname_available_dir() is OK.1599 */1600 ret = TRANSACTION_NAME_CONFLICT;1601 }1602 } else {1603 /*1604 * The file that is in the way isn't a loose1605 * reference. Report it as a low-level1606 * failure.1607 */1608 strbuf_addf(err, "unable to create lock file %s.lock; "1609 "non-directory in the way",1610 ref_file.buf);1611 }1612 goto error_return;1613 case SCLD_VANISHED:1614 /* Maybe another process was tidying up. Try again. */1615 if (--attempts_remaining > 0)1616 goto retry;1617 /* fall through */1618 default:1619 strbuf_addf(err, "unable to create directory for %s",1620 ref_file.buf);1621 goto error_return;1622 }16231624 if (!lock->lk)1625 lock->lk = xcalloc(1, sizeof(struct lock_file));16261627 if (hold_lock_file_for_update(lock->lk, ref_file.buf, LOCK_NO_DEREF) < 0) {1628 if (errno == ENOENT && --attempts_remaining > 0) {1629 /*1630 * Maybe somebody just deleted one of the1631 * directories leading to ref_file. Try1632 * again:1633 */1634 goto retry;1635 } else {1636 unable_to_lock_message(ref_file.buf, errno, err);1637 goto error_return;1638 }1639 }16401641 /*1642 * Now we hold the lock and can read the reference without1643 * fear that its value will change.1644 */16451646 if (files_read_raw_ref(&refs->base, refname,1647 lock->old_oid.hash, referent, type)) {1648 if (errno == ENOENT) {1649 if (mustexist) {1650 /* Garden variety missing reference. */1651 strbuf_addf(err, "unable to resolve reference '%s'",1652 refname);1653 goto error_return;1654 } else {1655 /*1656 * Reference is missing, but that's OK. We1657 * know that there is not a conflict with1658 * another loose reference because1659 * (supposing that we are trying to lock1660 * reference "refs/foo/bar"):1661 *1662 * - We were successfully able to create1663 * the lockfile refs/foo/bar.lock, so we1664 * know there cannot be a loose reference1665 * named "refs/foo".1666 *1667 * - We got ENOENT and not EISDIR, so we1668 * know that there cannot be a loose1669 * reference named "refs/foo/bar/baz".1670 */1671 }1672 } else if (errno == EISDIR) {1673 /*1674 * There is a directory in the way. It might have1675 * contained references that have been deleted. If1676 * we don't require that the reference already1677 * exists, try to remove the directory so that it1678 * doesn't cause trouble when we want to rename the1679 * lockfile into place later.1680 */1681 if (mustexist) {1682 /* Garden variety missing reference. */1683 strbuf_addf(err, "unable to resolve reference '%s'",1684 refname);1685 goto error_return;1686 } else if (remove_dir_recursively(&ref_file,1687 REMOVE_DIR_EMPTY_ONLY)) {1688 if (verify_refname_available_dir(1689 refname, extras, skip,1690 get_loose_refs(refs),1691 err)) {1692 /*1693 * The error message set by1694 * verify_refname_available() is OK.1695 */1696 ret = TRANSACTION_NAME_CONFLICT;1697 goto error_return;1698 } else {1699 /*1700 * We can't delete the directory,1701 * but we also don't know of any1702 * references that it should1703 * contain.1704 */1705 strbuf_addf(err, "there is a non-empty directory '%s' "1706 "blocking reference '%s'",1707 ref_file.buf, refname);1708 goto error_return;1709 }1710 }1711 } else if (errno == EINVAL && (*type & REF_ISBROKEN)) {1712 strbuf_addf(err, "unable to resolve reference '%s': "1713 "reference broken", refname);1714 goto error_return;1715 } else {1716 strbuf_addf(err, "unable to resolve reference '%s': %s",1717 refname, strerror(errno));1718 goto error_return;1719 }17201721 /*1722 * If the ref did not exist and we are creating it,1723 * make sure there is no existing packed ref whose1724 * name begins with our refname, nor a packed ref1725 * whose name is a proper prefix of our refname.1726 */1727 if (verify_refname_available_dir(1728 refname, extras, skip,1729 get_packed_refs(refs),1730 err)) {1731 goto error_return;1732 }1733 }17341735 ret = 0;1736 goto out;17371738error_return:1739 unlock_ref(lock);1740 *lock_p = NULL;17411742out:1743 strbuf_release(&ref_file);1744 return ret;1745}17461747/*1748 * Peel the entry (if possible) and return its new peel_status. If1749 * repeel is true, re-peel the entry even if there is an old peeled1750 * value that is already stored in it.1751 *1752 * It is OK to call this function with a packed reference entry that1753 * might be stale and might even refer to an object that has since1754 * been garbage-collected. In such a case, if the entry has1755 * REF_KNOWS_PEELED then leave the status unchanged and return1756 * PEEL_PEELED or PEEL_NON_TAG; otherwise, return PEEL_INVALID.1757 */1758static enum peel_status peel_entry(struct ref_entry *entry, int repeel)1759{1760 enum peel_status status;17611762 if (entry->flag & REF_KNOWS_PEELED) {1763 if (repeel) {1764 entry->flag &= ~REF_KNOWS_PEELED;1765 oidclr(&entry->u.value.peeled);1766 } else {1767 return is_null_oid(&entry->u.value.peeled) ?1768 PEEL_NON_TAG : PEEL_PEELED;1769 }1770 }1771 if (entry->flag & REF_ISBROKEN)1772 return PEEL_BROKEN;1773 if (entry->flag & REF_ISSYMREF)1774 return PEEL_IS_SYMREF;17751776 status = peel_object(entry->u.value.oid.hash, entry->u.value.peeled.hash);1777 if (status == PEEL_PEELED || status == PEEL_NON_TAG)1778 entry->flag |= REF_KNOWS_PEELED;1779 return status;1780}17811782static int files_peel_ref(struct ref_store *ref_store,1783 const char *refname, unsigned char *sha1)1784{1785 struct files_ref_store *refs = files_downcast(ref_store, 0, "peel_ref");1786 int flag;1787 unsigned char base[20];17881789 if (current_ref_iter && current_ref_iter->refname == refname) {1790 struct object_id peeled;17911792 if (ref_iterator_peel(current_ref_iter, &peeled))1793 return -1;1794 hashcpy(sha1, peeled.hash);1795 return 0;1796 }17971798 if (read_ref_full(refname, RESOLVE_REF_READING, base, &flag))1799 return -1;18001801 /*1802 * If the reference is packed, read its ref_entry from the1803 * cache in the hope that we already know its peeled value.1804 * We only try this optimization on packed references because1805 * (a) forcing the filling of the loose reference cache could1806 * be expensive and (b) loose references anyway usually do not1807 * have REF_KNOWS_PEELED.1808 */1809 if (flag & REF_ISPACKED) {1810 struct ref_entry *r = get_packed_ref(refs, refname);1811 if (r) {1812 if (peel_entry(r, 0))1813 return -1;1814 hashcpy(sha1, r->u.value.peeled.hash);1815 return 0;1816 }1817 }18181819 return peel_object(base, sha1);1820}18211822struct files_ref_iterator {1823 struct ref_iterator base;18241825 struct packed_ref_cache *packed_ref_cache;1826 struct ref_iterator *iter0;1827 unsigned int flags;1828};18291830static int files_ref_iterator_advance(struct ref_iterator *ref_iterator)1831{1832 struct files_ref_iterator *iter =1833 (struct files_ref_iterator *)ref_iterator;1834 int ok;18351836 while ((ok = ref_iterator_advance(iter->iter0)) == ITER_OK) {1837 if (iter->flags & DO_FOR_EACH_PER_WORKTREE_ONLY &&1838 ref_type(iter->iter0->refname) != REF_TYPE_PER_WORKTREE)1839 continue;18401841 if (!(iter->flags & DO_FOR_EACH_INCLUDE_BROKEN) &&1842 !ref_resolves_to_object(iter->iter0->refname,1843 iter->iter0->oid,1844 iter->iter0->flags))1845 continue;18461847 iter->base.refname = iter->iter0->refname;1848 iter->base.oid = iter->iter0->oid;1849 iter->base.flags = iter->iter0->flags;1850 return ITER_OK;1851 }18521853 iter->iter0 = NULL;1854 if (ref_iterator_abort(ref_iterator) != ITER_DONE)1855 ok = ITER_ERROR;18561857 return ok;1858}18591860static int files_ref_iterator_peel(struct ref_iterator *ref_iterator,1861 struct object_id *peeled)1862{1863 struct files_ref_iterator *iter =1864 (struct files_ref_iterator *)ref_iterator;18651866 return ref_iterator_peel(iter->iter0, peeled);1867}18681869static int files_ref_iterator_abort(struct ref_iterator *ref_iterator)1870{1871 struct files_ref_iterator *iter =1872 (struct files_ref_iterator *)ref_iterator;1873 int ok = ITER_DONE;18741875 if (iter->iter0)1876 ok = ref_iterator_abort(iter->iter0);18771878 release_packed_ref_cache(iter->packed_ref_cache);1879 base_ref_iterator_free(ref_iterator);1880 return ok;1881}18821883static struct ref_iterator_vtable files_ref_iterator_vtable = {1884 files_ref_iterator_advance,1885 files_ref_iterator_peel,1886 files_ref_iterator_abort1887};18881889static struct ref_iterator *files_ref_iterator_begin(1890 struct ref_store *ref_store,1891 const char *prefix, unsigned int flags)1892{1893 struct files_ref_store *refs =1894 files_downcast(ref_store, 1, "ref_iterator_begin");1895 struct ref_dir *loose_dir, *packed_dir;1896 struct ref_iterator *loose_iter, *packed_iter;1897 struct files_ref_iterator *iter;1898 struct ref_iterator *ref_iterator;18991900 if (!refs)1901 return empty_ref_iterator_begin();19021903 if (ref_paranoia < 0)1904 ref_paranoia = git_env_bool("GIT_REF_PARANOIA", 0);1905 if (ref_paranoia)1906 flags |= DO_FOR_EACH_INCLUDE_BROKEN;19071908 iter = xcalloc(1, sizeof(*iter));1909 ref_iterator = &iter->base;1910 base_ref_iterator_init(ref_iterator, &files_ref_iterator_vtable);19111912 /*1913 * We must make sure that all loose refs are read before1914 * accessing the packed-refs file; this avoids a race1915 * condition if loose refs are migrated to the packed-refs1916 * file by a simultaneous process, but our in-memory view is1917 * from before the migration. We ensure this as follows:1918 * First, we call prime_ref_dir(), which pre-reads the loose1919 * references for the subtree into the cache. (If they've1920 * already been read, that's OK; we only need to guarantee1921 * that they're read before the packed refs, not *how much*1922 * before.) After that, we call get_packed_ref_cache(), which1923 * internally checks whether the packed-ref cache is up to1924 * date with what is on disk, and re-reads it if not.1925 */19261927 loose_dir = get_loose_refs(refs);19281929 if (prefix && *prefix)1930 loose_dir = find_containing_dir(loose_dir, prefix, 0);19311932 if (loose_dir) {1933 prime_ref_dir(loose_dir);1934 loose_iter = cache_ref_iterator_begin(loose_dir);1935 } else {1936 /* There's nothing to iterate over. */1937 loose_iter = empty_ref_iterator_begin();1938 }19391940 iter->packed_ref_cache = get_packed_ref_cache(refs);1941 acquire_packed_ref_cache(iter->packed_ref_cache);1942 packed_dir = get_packed_ref_dir(iter->packed_ref_cache);19431944 if (prefix && *prefix)1945 packed_dir = find_containing_dir(packed_dir, prefix, 0);19461947 if (packed_dir) {1948 packed_iter = cache_ref_iterator_begin(packed_dir);1949 } else {1950 /* There's nothing to iterate over. */1951 packed_iter = empty_ref_iterator_begin();1952 }19531954 iter->iter0 = overlay_ref_iterator_begin(loose_iter, packed_iter);1955 iter->flags = flags;19561957 return ref_iterator;1958}19591960/*1961 * Verify that the reference locked by lock has the value old_sha1.1962 * Fail if the reference doesn't exist and mustexist is set. Return 01963 * on success. On error, write an error message to err, set errno, and1964 * return a negative value.1965 */1966static int verify_lock(struct ref_lock *lock,1967 const unsigned char *old_sha1, int mustexist,1968 struct strbuf *err)1969{1970 assert(err);19711972 if (read_ref_full(lock->ref_name,1973 mustexist ? RESOLVE_REF_READING : 0,1974 lock->old_oid.hash, NULL)) {1975 if (old_sha1) {1976 int save_errno = errno;1977 strbuf_addf(err, "can't verify ref '%s'", lock->ref_name);1978 errno = save_errno;1979 return -1;1980 } else {1981 oidclr(&lock->old_oid);1982 return 0;1983 }1984 }1985 if (old_sha1 && hashcmp(lock->old_oid.hash, old_sha1)) {1986 strbuf_addf(err, "ref '%s' is at %s but expected %s",1987 lock->ref_name,1988 oid_to_hex(&lock->old_oid),1989 sha1_to_hex(old_sha1));1990 errno = EBUSY;1991 return -1;1992 }1993 return 0;1994}19951996static int remove_empty_directories(struct strbuf *path)1997{1998 /*1999 * we want to create a file but there is a directory there;2000 * if that is an empty directory (or a directory that contains2001 * only empty directories), remove them.2002 */2003 return remove_dir_recursively(path, REMOVE_DIR_EMPTY_ONLY);2004}20052006static int create_reflock(const char *path, void *cb)2007{2008 struct lock_file *lk = cb;20092010 return hold_lock_file_for_update(lk, path, LOCK_NO_DEREF) < 0 ? -1 : 0;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 mustexist = (old_sha1 && !is_null_sha1(old_sha1));2029 int resolve_flags = RESOLVE_REF_NO_RECURSE;2030 int resolved;20312032 files_assert_main_repository(refs, "lock_ref_sha1_basic");2033 assert(err);20342035 lock = xcalloc(1, sizeof(struct ref_lock));20362037 if (mustexist)2038 resolve_flags |= RESOLVE_REF_READING;2039 if (flags & REF_DELETING)2040 resolve_flags |= RESOLVE_REF_ALLOW_BAD_NAME;20412042 strbuf_git_path(&ref_file, "%s", refname);2043 resolved = !!resolve_ref_unsafe(refname, resolve_flags,2044 lock->old_oid.hash, type);2045 if (!resolved && errno == EISDIR) {2046 /*2047 * we are trying to lock foo but we used to2048 * have foo/bar which now does not exist;2049 * it is normal for the empty directory 'foo'2050 * to remain.2051 */2052 if (remove_empty_directories(&ref_file)) {2053 last_errno = errno;2054 if (!verify_refname_available_dir(2055 refname, extras, skip,2056 get_loose_refs(refs), err))2057 strbuf_addf(err, "there are still refs under '%s'",2058 refname);2059 goto error_return;2060 }2061 resolved = !!resolve_ref_unsafe(refname, resolve_flags,2062 lock->old_oid.hash, type);2063 }2064 if (!resolved) {2065 last_errno = errno;2066 if (last_errno != ENOTDIR ||2067 !verify_refname_available_dir(2068 refname, extras, skip,2069 get_loose_refs(refs), err))2070 strbuf_addf(err, "unable to resolve reference '%s': %s",2071 refname, strerror(last_errno));20722073 goto error_return;2074 }20752076 /*2077 * If the ref did not exist and we are creating it, make sure2078 * there is no existing packed ref whose name begins with our2079 * refname, nor a packed ref whose name is a proper prefix of2080 * our refname.2081 */2082 if (is_null_oid(&lock->old_oid) &&2083 verify_refname_available_dir(refname, extras, skip,2084 get_packed_refs(refs),2085 err)) {2086 last_errno = ENOTDIR;2087 goto error_return;2088 }20892090 lock->lk = xcalloc(1, sizeof(struct lock_file));20912092 lock->ref_name = xstrdup(refname);20932094 if (raceproof_create_file(ref_file.buf, create_reflock, lock->lk)) {2095 last_errno = errno;2096 unable_to_lock_message(ref_file.buf, errno, err);2097 goto error_return;2098 }20992100 if (verify_lock(lock, old_sha1, mustexist, err)) {2101 last_errno = errno;2102 goto error_return;2103 }2104 goto out;21052106 error_return:2107 unlock_ref(lock);2108 lock = NULL;21092110 out:2111 strbuf_release(&ref_file);2112 errno = last_errno;2113 return lock;2114}21152116/*2117 * Write an entry to the packed-refs file for the specified refname.2118 * If peeled is non-NULL, write it as the entry's peeled value.2119 */2120static void write_packed_entry(FILE *fh, char *refname, unsigned char *sha1,2121 unsigned char *peeled)2122{2123 fprintf_or_die(fh, "%s %s\n", sha1_to_hex(sha1), refname);2124 if (peeled)2125 fprintf_or_die(fh, "^%s\n", sha1_to_hex(peeled));2126}21272128/*2129 * An each_ref_entry_fn that writes the entry to a packed-refs file.2130 */2131static int write_packed_entry_fn(struct ref_entry *entry, void *cb_data)2132{2133 enum peel_status peel_status = peel_entry(entry, 0);21342135 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)2136 error("internal error: %s is not a valid packed reference!",2137 entry->name);2138 write_packed_entry(cb_data, entry->name, entry->u.value.oid.hash,2139 peel_status == PEEL_PEELED ?2140 entry->u.value.peeled.hash : NULL);2141 return 0;2142}21432144/*2145 * Lock the packed-refs file for writing. Flags is passed to2146 * hold_lock_file_for_update(). Return 0 on success. On errors, set2147 * errno appropriately and return a nonzero value.2148 */2149static int lock_packed_refs(struct files_ref_store *refs, int flags)2150{2151 static int timeout_configured = 0;2152 static int timeout_value = 1000;2153 struct packed_ref_cache *packed_ref_cache;21542155 files_assert_main_repository(refs, "lock_packed_refs");21562157 if (!timeout_configured) {2158 git_config_get_int("core.packedrefstimeout", &timeout_value);2159 timeout_configured = 1;2160 }21612162 if (hold_lock_file_for_update_timeout(2163 &packlock, git_path("packed-refs"),2164 flags, timeout_value) < 0)2165 return -1;2166 /*2167 * Get the current packed-refs while holding the lock. If the2168 * packed-refs file has been modified since we last read it,2169 * this will automatically invalidate the cache and re-read2170 * the packed-refs file.2171 */2172 packed_ref_cache = get_packed_ref_cache(refs);2173 packed_ref_cache->lock = &packlock;2174 /* Increment the reference count to prevent it from being freed: */2175 acquire_packed_ref_cache(packed_ref_cache);2176 return 0;2177}21782179/*2180 * Write the current version of the packed refs cache from memory to2181 * disk. The packed-refs file must already be locked for writing (see2182 * lock_packed_refs()). Return zero on success. On errors, set errno2183 * and return a nonzero value2184 */2185static int commit_packed_refs(struct files_ref_store *refs)2186{2187 struct packed_ref_cache *packed_ref_cache =2188 get_packed_ref_cache(refs);2189 int error = 0;2190 int save_errno = 0;2191 FILE *out;21922193 files_assert_main_repository(refs, "commit_packed_refs");21942195 if (!packed_ref_cache->lock)2196 die("internal error: packed-refs not locked");21972198 out = fdopen_lock_file(packed_ref_cache->lock, "w");2199 if (!out)2200 die_errno("unable to fdopen packed-refs descriptor");22012202 fprintf_or_die(out, "%s", PACKED_REFS_HEADER);2203 do_for_each_entry_in_dir(get_packed_ref_dir(packed_ref_cache),2204 0, write_packed_entry_fn, out);22052206 if (commit_lock_file(packed_ref_cache->lock)) {2207 save_errno = errno;2208 error = -1;2209 }2210 packed_ref_cache->lock = NULL;2211 release_packed_ref_cache(packed_ref_cache);2212 errno = save_errno;2213 return error;2214}22152216/*2217 * Rollback the lockfile for the packed-refs file, and discard the2218 * in-memory packed reference cache. (The packed-refs file will be2219 * read anew if it is needed again after this function is called.)2220 */2221static void rollback_packed_refs(struct files_ref_store *refs)2222{2223 struct packed_ref_cache *packed_ref_cache =2224 get_packed_ref_cache(refs);22252226 files_assert_main_repository(refs, "rollback_packed_refs");22272228 if (!packed_ref_cache->lock)2229 die("internal error: packed-refs not locked");2230 rollback_lock_file(packed_ref_cache->lock);2231 packed_ref_cache->lock = NULL;2232 release_packed_ref_cache(packed_ref_cache);2233 clear_packed_ref_cache(refs);2234}22352236struct ref_to_prune {2237 struct ref_to_prune *next;2238 unsigned char sha1[20];2239 char name[FLEX_ARRAY];2240};22412242struct pack_refs_cb_data {2243 unsigned int flags;2244 struct ref_dir *packed_refs;2245 struct ref_to_prune *ref_to_prune;2246};22472248/*2249 * An each_ref_entry_fn that is run over loose references only. If2250 * the loose reference can be packed, add an entry in the packed ref2251 * cache. If the reference should be pruned, also add it to2252 * ref_to_prune in the pack_refs_cb_data.2253 */2254static int pack_if_possible_fn(struct ref_entry *entry, void *cb_data)2255{2256 struct pack_refs_cb_data *cb = cb_data;2257 enum peel_status peel_status;2258 struct ref_entry *packed_entry;2259 int is_tag_ref = starts_with(entry->name, "refs/tags/");22602261 /* Do not pack per-worktree refs: */2262 if (ref_type(entry->name) != REF_TYPE_NORMAL)2263 return 0;22642265 /* ALWAYS pack tags */2266 if (!(cb->flags & PACK_REFS_ALL) && !is_tag_ref)2267 return 0;22682269 /* Do not pack symbolic or broken refs: */2270 if ((entry->flag & REF_ISSYMREF) || !entry_resolves_to_object(entry))2271 return 0;22722273 /* Add a packed ref cache entry equivalent to the loose entry. */2274 peel_status = peel_entry(entry, 1);2275 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)2276 die("internal error peeling reference %s (%s)",2277 entry->name, oid_to_hex(&entry->u.value.oid));2278 packed_entry = find_ref(cb->packed_refs, entry->name);2279 if (packed_entry) {2280 /* Overwrite existing packed entry with info from loose entry */2281 packed_entry->flag = REF_ISPACKED | REF_KNOWS_PEELED;2282 oidcpy(&packed_entry->u.value.oid, &entry->u.value.oid);2283 } else {2284 packed_entry = create_ref_entry(entry->name, entry->u.value.oid.hash,2285 REF_ISPACKED | REF_KNOWS_PEELED, 0);2286 add_ref(cb->packed_refs, packed_entry);2287 }2288 oidcpy(&packed_entry->u.value.peeled, &entry->u.value.peeled);22892290 /* Schedule the loose reference for pruning if requested. */2291 if ((cb->flags & PACK_REFS_PRUNE)) {2292 struct ref_to_prune *n;2293 FLEX_ALLOC_STR(n, name, entry->name);2294 hashcpy(n->sha1, entry->u.value.oid.hash);2295 n->next = cb->ref_to_prune;2296 cb->ref_to_prune = n;2297 }2298 return 0;2299}23002301enum {2302 REMOVE_EMPTY_PARENTS_REF = 0x01,2303 REMOVE_EMPTY_PARENTS_REFLOG = 0x022304};23052306/*2307 * Remove empty parent directories associated with the specified2308 * reference and/or its reflog, but spare [logs/]refs/ and immediate2309 * subdirs. flags is a combination of REMOVE_EMPTY_PARENTS_REF and/or2310 * REMOVE_EMPTY_PARENTS_REFLOG.2311 */2312static void try_remove_empty_parents(const char *refname, unsigned int flags)2313{2314 struct strbuf buf = STRBUF_INIT;2315 char *p, *q;2316 int i;23172318 strbuf_addstr(&buf, refname);2319 p = buf.buf;2320 for (i = 0; i < 2; i++) { /* refs/{heads,tags,...}/ */2321 while (*p && *p != '/')2322 p++;2323 /* tolerate duplicate slashes; see check_refname_format() */2324 while (*p == '/')2325 p++;2326 }2327 q = buf.buf + buf.len;2328 while (flags & (REMOVE_EMPTY_PARENTS_REF | REMOVE_EMPTY_PARENTS_REFLOG)) {2329 while (q > p && *q != '/')2330 q--;2331 while (q > p && *(q-1) == '/')2332 q--;2333 if (q == p)2334 break;2335 strbuf_setlen(&buf, q - buf.buf);2336 if ((flags & REMOVE_EMPTY_PARENTS_REF) &&2337 rmdir(git_path("%s", buf.buf)))2338 flags &= ~REMOVE_EMPTY_PARENTS_REF;2339 if ((flags & REMOVE_EMPTY_PARENTS_REFLOG) &&2340 rmdir(git_path("logs/%s", buf.buf)))2341 flags &= ~REMOVE_EMPTY_PARENTS_REFLOG;2342 }2343 strbuf_release(&buf);2344}23452346/* make sure nobody touched the ref, and unlink */2347static void prune_ref(struct ref_to_prune *r)2348{2349 struct ref_transaction *transaction;2350 struct strbuf err = STRBUF_INIT;23512352 if (check_refname_format(r->name, 0))2353 return;23542355 transaction = ref_transaction_begin(&err);2356 if (!transaction ||2357 ref_transaction_delete(transaction, r->name, r->sha1,2358 REF_ISPRUNING | REF_NODEREF, NULL, &err) ||2359 ref_transaction_commit(transaction, &err)) {2360 ref_transaction_free(transaction);2361 error("%s", err.buf);2362 strbuf_release(&err);2363 return;2364 }2365 ref_transaction_free(transaction);2366 strbuf_release(&err);2367}23682369static void prune_refs(struct ref_to_prune *r)2370{2371 while (r) {2372 prune_ref(r);2373 r = r->next;2374 }2375}23762377static int files_pack_refs(struct ref_store *ref_store, unsigned int flags)2378{2379 struct files_ref_store *refs =2380 files_downcast(ref_store, 0, "pack_refs");2381 struct pack_refs_cb_data cbdata;23822383 memset(&cbdata, 0, sizeof(cbdata));2384 cbdata.flags = flags;23852386 lock_packed_refs(refs, LOCK_DIE_ON_ERROR);2387 cbdata.packed_refs = get_packed_refs(refs);23882389 do_for_each_entry_in_dir(get_loose_refs(refs), 0,2390 pack_if_possible_fn, &cbdata);23912392 if (commit_packed_refs(refs))2393 die_errno("unable to overwrite old ref-pack file");23942395 prune_refs(cbdata.ref_to_prune);2396 return 0;2397}23982399/*2400 * Rewrite the packed-refs file, omitting any refs listed in2401 * 'refnames'. On error, leave packed-refs unchanged, write an error2402 * message to 'err', and return a nonzero value.2403 *2404 * The refs in 'refnames' needn't be sorted. `err` must not be NULL.2405 */2406static int repack_without_refs(struct files_ref_store *refs,2407 struct string_list *refnames, struct strbuf *err)2408{2409 struct ref_dir *packed;2410 struct string_list_item *refname;2411 int ret, needs_repacking = 0, removed = 0;24122413 files_assert_main_repository(refs, "repack_without_refs");2414 assert(err);24152416 /* Look for a packed ref */2417 for_each_string_list_item(refname, refnames) {2418 if (get_packed_ref(refs, refname->string)) {2419 needs_repacking = 1;2420 break;2421 }2422 }24232424 /* Avoid locking if we have nothing to do */2425 if (!needs_repacking)2426 return 0; /* no refname exists in packed refs */24272428 if (lock_packed_refs(refs, 0)) {2429 unable_to_lock_message(git_path("packed-refs"), errno, err);2430 return -1;2431 }2432 packed = get_packed_refs(refs);24332434 /* Remove refnames from the cache */2435 for_each_string_list_item(refname, refnames)2436 if (remove_entry(packed, refname->string) != -1)2437 removed = 1;2438 if (!removed) {2439 /*2440 * All packed entries disappeared while we were2441 * acquiring the lock.2442 */2443 rollback_packed_refs(refs);2444 return 0;2445 }24462447 /* Write what remains */2448 ret = commit_packed_refs(refs);2449 if (ret)2450 strbuf_addf(err, "unable to overwrite old ref-pack file: %s",2451 strerror(errno));2452 return ret;2453}24542455static int files_delete_refs(struct ref_store *ref_store,2456 struct string_list *refnames, unsigned int flags)2457{2458 struct files_ref_store *refs =2459 files_downcast(ref_store, 0, "delete_refs");2460 struct strbuf err = STRBUF_INIT;2461 int i, result = 0;24622463 if (!refnames->nr)2464 return 0;24652466 result = repack_without_refs(refs, refnames, &err);2467 if (result) {2468 /*2469 * If we failed to rewrite the packed-refs file, then2470 * it is unsafe to try to remove loose refs, because2471 * doing so might expose an obsolete packed value for2472 * a reference that might even point at an object that2473 * has been garbage collected.2474 */2475 if (refnames->nr == 1)2476 error(_("could not delete reference %s: %s"),2477 refnames->items[0].string, err.buf);2478 else2479 error(_("could not delete references: %s"), err.buf);24802481 goto out;2482 }24832484 for (i = 0; i < refnames->nr; i++) {2485 const char *refname = refnames->items[i].string;24862487 if (delete_ref(NULL, refname, NULL, flags))2488 result |= error(_("could not remove reference %s"), refname);2489 }24902491out:2492 strbuf_release(&err);2493 return result;2494}24952496/*2497 * People using contrib's git-new-workdir have .git/logs/refs ->2498 * /some/other/path/.git/logs/refs, and that may live on another device.2499 *2500 * IOW, to avoid cross device rename errors, the temporary renamed log must2501 * live into logs/refs.2502 */2503#define TMP_RENAMED_LOG "logs/refs/.tmp-renamed-log"25042505static int rename_tmp_log_callback(const char *path, void *cb)2506{2507 int *true_errno = cb;25082509 if (rename(git_path(TMP_RENAMED_LOG), path)) {2510 /*2511 * rename(a, b) when b is an existing directory ought2512 * to result in ISDIR, but Solaris 5.8 gives ENOTDIR.2513 * Sheesh. Record the true errno for error reporting,2514 * but report EISDIR to raceproof_create_file() so2515 * that it knows to retry.2516 */2517 *true_errno = errno;2518 if (errno == ENOTDIR)2519 errno = EISDIR;2520 return -1;2521 } else {2522 return 0;2523 }2524}25252526static int rename_tmp_log(const char *newrefname)2527{2528 char *path = git_pathdup("logs/%s", newrefname);2529 int ret, true_errno;25302531 ret = raceproof_create_file(path, rename_tmp_log_callback, &true_errno);2532 if (ret) {2533 if (errno == EISDIR)2534 error("directory not empty: %s", path);2535 else2536 error("unable to move logfile %s to %s: %s",2537 git_path(TMP_RENAMED_LOG), path,2538 strerror(true_errno));2539 }25402541 free(path);2542 return ret;2543}25442545static int files_verify_refname_available(struct ref_store *ref_store,2546 const char *newname,2547 const struct string_list *extras,2548 const struct string_list *skip,2549 struct strbuf *err)2550{2551 struct files_ref_store *refs =2552 files_downcast(ref_store, 1, "verify_refname_available");2553 struct ref_dir *packed_refs = get_packed_refs(refs);2554 struct ref_dir *loose_refs = get_loose_refs(refs);25552556 if (verify_refname_available_dir(newname, extras, skip,2557 packed_refs, err) ||2558 verify_refname_available_dir(newname, extras, skip,2559 loose_refs, err))2560 return -1;25612562 return 0;2563}25642565static int write_ref_to_lockfile(struct ref_lock *lock,2566 const unsigned char *sha1, struct strbuf *err);2567static int commit_ref_update(struct files_ref_store *refs,2568 struct ref_lock *lock,2569 const unsigned char *sha1, const char *logmsg,2570 struct strbuf *err);25712572static int files_rename_ref(struct ref_store *ref_store,2573 const char *oldrefname, const char *newrefname,2574 const char *logmsg)2575{2576 struct files_ref_store *refs =2577 files_downcast(ref_store, 0, "rename_ref");2578 unsigned char sha1[20], orig_sha1[20];2579 int flag = 0, logmoved = 0;2580 struct ref_lock *lock;2581 struct stat loginfo;2582 int log = !lstat(git_path("logs/%s", oldrefname), &loginfo);2583 struct strbuf err = STRBUF_INIT;25842585 if (log && S_ISLNK(loginfo.st_mode))2586 return error("reflog for %s is a symlink", oldrefname);25872588 if (!resolve_ref_unsafe(oldrefname, RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,2589 orig_sha1, &flag))2590 return error("refname %s not found", oldrefname);25912592 if (flag & REF_ISSYMREF)2593 return error("refname %s is a symbolic ref, renaming it is not supported",2594 oldrefname);2595 if (!rename_ref_available(oldrefname, newrefname))2596 return 1;25972598 if (log && rename(git_path("logs/%s", oldrefname), git_path(TMP_RENAMED_LOG)))2599 return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",2600 oldrefname, strerror(errno));26012602 if (delete_ref(logmsg, oldrefname, orig_sha1, REF_NODEREF)) {2603 error("unable to delete old %s", oldrefname);2604 goto rollback;2605 }26062607 /*2608 * Since we are doing a shallow lookup, sha1 is not the2609 * correct value to pass to delete_ref as old_sha1. But that2610 * doesn't matter, because an old_sha1 check wouldn't add to2611 * the safety anyway; we want to delete the reference whatever2612 * its current value.2613 */2614 if (!read_ref_full(newrefname, RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,2615 sha1, NULL) &&2616 delete_ref(NULL, newrefname, NULL, REF_NODEREF)) {2617 if (errno == EISDIR) {2618 struct strbuf path = STRBUF_INIT;2619 int result;26202621 strbuf_git_path(&path, "%s", newrefname);2622 result = remove_empty_directories(&path);2623 strbuf_release(&path);26242625 if (result) {2626 error("Directory not empty: %s", newrefname);2627 goto rollback;2628 }2629 } else {2630 error("unable to delete existing %s", newrefname);2631 goto rollback;2632 }2633 }26342635 if (log && rename_tmp_log(newrefname))2636 goto rollback;26372638 logmoved = log;26392640 lock = lock_ref_sha1_basic(refs, newrefname, NULL, NULL, NULL,2641 REF_NODEREF, NULL, &err);2642 if (!lock) {2643 error("unable to rename '%s' to '%s': %s", oldrefname, newrefname, err.buf);2644 strbuf_release(&err);2645 goto rollback;2646 }2647 hashcpy(lock->old_oid.hash, orig_sha1);26482649 if (write_ref_to_lockfile(lock, orig_sha1, &err) ||2650 commit_ref_update(refs, lock, orig_sha1, logmsg, &err)) {2651 error("unable to write current sha1 into %s: %s", newrefname, err.buf);2652 strbuf_release(&err);2653 goto rollback;2654 }26552656 return 0;26572658 rollback:2659 lock = lock_ref_sha1_basic(refs, oldrefname, NULL, NULL, NULL,2660 REF_NODEREF, NULL, &err);2661 if (!lock) {2662 error("unable to lock %s for rollback: %s", oldrefname, err.buf);2663 strbuf_release(&err);2664 goto rollbacklog;2665 }26662667 flag = log_all_ref_updates;2668 log_all_ref_updates = LOG_REFS_NONE;2669 if (write_ref_to_lockfile(lock, orig_sha1, &err) ||2670 commit_ref_update(refs, lock, orig_sha1, NULL, &err)) {2671 error("unable to write current sha1 into %s: %s", oldrefname, err.buf);2672 strbuf_release(&err);2673 }2674 log_all_ref_updates = flag;26752676 rollbacklog:2677 if (logmoved && rename(git_path("logs/%s", newrefname), git_path("logs/%s", oldrefname)))2678 error("unable to restore logfile %s from %s: %s",2679 oldrefname, newrefname, strerror(errno));2680 if (!logmoved && log &&2681 rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", oldrefname)))2682 error("unable to restore logfile %s from "TMP_RENAMED_LOG": %s",2683 oldrefname, strerror(errno));26842685 return 1;2686}26872688static int close_ref(struct ref_lock *lock)2689{2690 if (close_lock_file(lock->lk))2691 return -1;2692 return 0;2693}26942695static int commit_ref(struct ref_lock *lock)2696{2697 char *path = get_locked_file_path(lock->lk);2698 struct stat st;26992700 if (!lstat(path, &st) && S_ISDIR(st.st_mode)) {2701 /*2702 * There is a directory at the path we want to rename2703 * the lockfile to. Hopefully it is empty; try to2704 * delete it.2705 */2706 size_t len = strlen(path);2707 struct strbuf sb_path = STRBUF_INIT;27082709 strbuf_attach(&sb_path, path, len, len);27102711 /*2712 * If this fails, commit_lock_file() will also fail2713 * and will report the problem.2714 */2715 remove_empty_directories(&sb_path);2716 strbuf_release(&sb_path);2717 } else {2718 free(path);2719 }27202721 if (commit_lock_file(lock->lk))2722 return -1;2723 return 0;2724}27252726static int open_or_create_logfile(const char *path, void *cb)2727{2728 int *fd = cb;27292730 *fd = open(path, O_APPEND | O_WRONLY | O_CREAT, 0666);2731 return (*fd < 0) ? -1 : 0;2732}27332734/*2735 * Create a reflog for a ref. If force_create = 0, only create the2736 * reflog for certain refs (those for which should_autocreate_reflog2737 * returns non-zero). Otherwise, create it regardless of the reference2738 * name. If the logfile already existed or was created, return 0 and2739 * set *logfd to the file descriptor opened for appending to the file.2740 * If no logfile exists and we decided not to create one, return 0 and2741 * set *logfd to -1. On failure, fill in *err, set *logfd to -1, and2742 * return -1.2743 */2744static int log_ref_setup(const char *refname, int force_create,2745 int *logfd, struct strbuf *err)2746{2747 char *logfile = git_pathdup("logs/%s", refname);27482749 if (force_create || should_autocreate_reflog(refname)) {2750 if (raceproof_create_file(logfile, open_or_create_logfile, logfd)) {2751 if (errno == ENOENT)2752 strbuf_addf(err, "unable to create directory for '%s': "2753 "%s", logfile, strerror(errno));2754 else if (errno == EISDIR)2755 strbuf_addf(err, "there are still logs under '%s'",2756 logfile);2757 else2758 strbuf_addf(err, "unable to append to '%s': %s",2759 logfile, strerror(errno));27602761 goto error;2762 }2763 } else {2764 *logfd = open(logfile, O_APPEND | O_WRONLY, 0666);2765 if (*logfd < 0) {2766 if (errno == ENOENT || errno == EISDIR) {2767 /*2768 * The logfile doesn't already exist,2769 * but that is not an error; it only2770 * means that we won't write log2771 * entries to it.2772 */2773 ;2774 } else {2775 strbuf_addf(err, "unable to append to '%s': %s",2776 logfile, strerror(errno));2777 goto error;2778 }2779 }2780 }27812782 if (*logfd >= 0)2783 adjust_shared_perm(logfile);27842785 free(logfile);2786 return 0;27872788error:2789 free(logfile);2790 return -1;2791}27922793static int files_create_reflog(struct ref_store *ref_store,2794 const char *refname, int force_create,2795 struct strbuf *err)2796{2797 int fd;27982799 /* Check validity (but we don't need the result): */2800 files_downcast(ref_store, 0, "create_reflog");28012802 if (log_ref_setup(refname, force_create, &fd, err))2803 return -1;28042805 if (fd >= 0)2806 close(fd);28072808 return 0;2809}28102811static int log_ref_write_fd(int fd, const unsigned char *old_sha1,2812 const unsigned char *new_sha1,2813 const char *committer, const char *msg)2814{2815 int msglen, written;2816 unsigned maxlen, len;2817 char *logrec;28182819 msglen = msg ? strlen(msg) : 0;2820 maxlen = strlen(committer) + msglen + 100;2821 logrec = xmalloc(maxlen);2822 len = xsnprintf(logrec, maxlen, "%s %s %s\n",2823 sha1_to_hex(old_sha1),2824 sha1_to_hex(new_sha1),2825 committer);2826 if (msglen)2827 len += copy_reflog_msg(logrec + len - 1, msg) - 1;28282829 written = len <= maxlen ? write_in_full(fd, logrec, len) : -1;2830 free(logrec);2831 if (written != len)2832 return -1;28332834 return 0;2835}28362837static int files_log_ref_write(const char *refname, const unsigned char *old_sha1,2838 const unsigned char *new_sha1, const char *msg,2839 int flags, struct strbuf *err)2840{2841 int logfd, result;28422843 if (log_all_ref_updates == LOG_REFS_UNSET)2844 log_all_ref_updates = is_bare_repository() ? LOG_REFS_NONE : LOG_REFS_NORMAL;28452846 result = log_ref_setup(refname, flags & REF_FORCE_CREATE_REFLOG,2847 &logfd, err);28482849 if (result)2850 return result;28512852 if (logfd < 0)2853 return 0;2854 result = log_ref_write_fd(logfd, old_sha1, new_sha1,2855 git_committer_info(0), msg);2856 if (result) {2857 int save_errno = errno;28582859 strbuf_addf(err, "unable to append to '%s': %s",2860 git_path("logs/%s", refname), strerror(save_errno));2861 close(logfd);2862 return -1;2863 }2864 if (close(logfd)) {2865 int save_errno = errno;28662867 strbuf_addf(err, "unable to append to '%s': %s",2868 git_path("logs/%s", refname), strerror(save_errno));2869 return -1;2870 }2871 return 0;2872}28732874/*2875 * Write sha1 into the open lockfile, then close the lockfile. On2876 * errors, rollback the lockfile, fill in *err and2877 * return -1.2878 */2879static int write_ref_to_lockfile(struct ref_lock *lock,2880 const unsigned char *sha1, struct strbuf *err)2881{2882 static char term = '\n';2883 struct object *o;2884 int fd;28852886 o = parse_object(sha1);2887 if (!o) {2888 strbuf_addf(err,2889 "trying to write ref '%s' with nonexistent object %s",2890 lock->ref_name, sha1_to_hex(sha1));2891 unlock_ref(lock);2892 return -1;2893 }2894 if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {2895 strbuf_addf(err,2896 "trying to write non-commit object %s to branch '%s'",2897 sha1_to_hex(sha1), lock->ref_name);2898 unlock_ref(lock);2899 return -1;2900 }2901 fd = get_lock_file_fd(lock->lk);2902 if (write_in_full(fd, sha1_to_hex(sha1), 40) != 40 ||2903 write_in_full(fd, &term, 1) != 1 ||2904 close_ref(lock) < 0) {2905 strbuf_addf(err,2906 "couldn't write '%s'", get_lock_file_path(lock->lk));2907 unlock_ref(lock);2908 return -1;2909 }2910 return 0;2911}29122913/*2914 * Commit a change to a loose reference that has already been written2915 * to the loose reference lockfile. Also update the reflogs if2916 * necessary, using the specified lockmsg (which can be NULL).2917 */2918static int commit_ref_update(struct files_ref_store *refs,2919 struct ref_lock *lock,2920 const unsigned char *sha1, const char *logmsg,2921 struct strbuf *err)2922{2923 files_assert_main_repository(refs, "commit_ref_update");29242925 clear_loose_ref_cache(refs);2926 if (files_log_ref_write(lock->ref_name, lock->old_oid.hash, sha1,2927 logmsg, 0, err)) {2928 char *old_msg = strbuf_detach(err, NULL);2929 strbuf_addf(err, "cannot update the ref '%s': %s",2930 lock->ref_name, old_msg);2931 free(old_msg);2932 unlock_ref(lock);2933 return -1;2934 }29352936 if (strcmp(lock->ref_name, "HEAD") != 0) {2937 /*2938 * Special hack: If a branch is updated directly and HEAD2939 * points to it (may happen on the remote side of a push2940 * for example) then logically the HEAD reflog should be2941 * updated too.2942 * A generic solution implies reverse symref information,2943 * but finding all symrefs pointing to the given branch2944 * would be rather costly for this rare event (the direct2945 * update of a branch) to be worth it. So let's cheat and2946 * check with HEAD only which should cover 99% of all usage2947 * scenarios (even 100% of the default ones).2948 */2949 unsigned char head_sha1[20];2950 int head_flag;2951 const char *head_ref;29522953 head_ref = resolve_ref_unsafe("HEAD", RESOLVE_REF_READING,2954 head_sha1, &head_flag);2955 if (head_ref && (head_flag & REF_ISSYMREF) &&2956 !strcmp(head_ref, lock->ref_name)) {2957 struct strbuf log_err = STRBUF_INIT;2958 if (files_log_ref_write("HEAD", lock->old_oid.hash, sha1,2959 logmsg, 0, &log_err)) {2960 error("%s", log_err.buf);2961 strbuf_release(&log_err);2962 }2963 }2964 }29652966 if (commit_ref(lock)) {2967 strbuf_addf(err, "couldn't set '%s'", lock->ref_name);2968 unlock_ref(lock);2969 return -1;2970 }29712972 unlock_ref(lock);2973 return 0;2974}29752976static int create_ref_symlink(struct ref_lock *lock, const char *target)2977{2978 int ret = -1;2979#ifndef NO_SYMLINK_HEAD2980 char *ref_path = get_locked_file_path(lock->lk);2981 unlink(ref_path);2982 ret = symlink(target, ref_path);2983 free(ref_path);29842985 if (ret)2986 fprintf(stderr, "no symlink - falling back to symbolic ref\n");2987#endif2988 return ret;2989}29902991static void update_symref_reflog(struct ref_lock *lock, const char *refname,2992 const char *target, const char *logmsg)2993{2994 struct strbuf err = STRBUF_INIT;2995 unsigned char new_sha1[20];2996 if (logmsg && !read_ref(target, new_sha1) &&2997 files_log_ref_write(refname, lock->old_oid.hash, new_sha1,2998 logmsg, 0, &err)) {2999 error("%s", err.buf);3000 strbuf_release(&err);3001 }3002}30033004static int create_symref_locked(struct ref_lock *lock, const char *refname,3005 const char *target, const char *logmsg)3006{3007 if (prefer_symlink_refs && !create_ref_symlink(lock, target)) {3008 update_symref_reflog(lock, refname, target, logmsg);3009 return 0;3010 }30113012 if (!fdopen_lock_file(lock->lk, "w"))3013 return error("unable to fdopen %s: %s",3014 lock->lk->tempfile.filename.buf, strerror(errno));30153016 update_symref_reflog(lock, refname, target, logmsg);30173018 /* no error check; commit_ref will check ferror */3019 fprintf(lock->lk->tempfile.fp, "ref: %s\n", target);3020 if (commit_ref(lock) < 0)3021 return error("unable to write symref for %s: %s", refname,3022 strerror(errno));3023 return 0;3024}30253026static int files_create_symref(struct ref_store *ref_store,3027 const char *refname, const char *target,3028 const char *logmsg)3029{3030 struct files_ref_store *refs =3031 files_downcast(ref_store, 0, "create_symref");3032 struct strbuf err = STRBUF_INIT;3033 struct ref_lock *lock;3034 int ret;30353036 lock = lock_ref_sha1_basic(refs, refname, NULL,3037 NULL, NULL, REF_NODEREF, NULL,3038 &err);3039 if (!lock) {3040 error("%s", err.buf);3041 strbuf_release(&err);3042 return -1;3043 }30443045 ret = create_symref_locked(lock, refname, target, logmsg);3046 unlock_ref(lock);3047 return ret;3048}30493050int set_worktree_head_symref(const char *gitdir, const char *target, const char *logmsg)3051{3052 static struct lock_file head_lock;3053 struct ref_lock *lock;3054 struct strbuf head_path = STRBUF_INIT;3055 const char *head_rel;3056 int ret;30573058 strbuf_addf(&head_path, "%s/HEAD", absolute_path(gitdir));3059 if (hold_lock_file_for_update(&head_lock, head_path.buf,3060 LOCK_NO_DEREF) < 0) {3061 struct strbuf err = STRBUF_INIT;3062 unable_to_lock_message(head_path.buf, errno, &err);3063 error("%s", err.buf);3064 strbuf_release(&err);3065 strbuf_release(&head_path);3066 return -1;3067 }30683069 /* head_rel will be "HEAD" for the main tree, "worktrees/wt/HEAD" for3070 linked trees */3071 head_rel = remove_leading_path(head_path.buf,3072 absolute_path(get_git_common_dir()));3073 /* to make use of create_symref_locked(), initialize ref_lock */3074 lock = xcalloc(1, sizeof(struct ref_lock));3075 lock->lk = &head_lock;3076 lock->ref_name = xstrdup(head_rel);30773078 ret = create_symref_locked(lock, head_rel, target, logmsg);30793080 unlock_ref(lock); /* will free lock */3081 strbuf_release(&head_path);3082 return ret;3083}30843085static int files_reflog_exists(struct ref_store *ref_store,3086 const char *refname)3087{3088 struct stat st;30893090 /* Check validity (but we don't need the result): */3091 files_downcast(ref_store, 0, "reflog_exists");30923093 return !lstat(git_path("logs/%s", refname), &st) &&3094 S_ISREG(st.st_mode);3095}30963097static int files_delete_reflog(struct ref_store *ref_store,3098 const char *refname)3099{3100 /* Check validity (but we don't need the result): */3101 files_downcast(ref_store, 0, "delete_reflog");31023103 return remove_path(git_path("logs/%s", refname));3104}31053106static int show_one_reflog_ent(struct strbuf *sb, each_reflog_ent_fn fn, void *cb_data)3107{3108 struct object_id ooid, noid;3109 char *email_end, *message;3110 unsigned long timestamp;3111 int tz;3112 const char *p = sb->buf;31133114 /* old SP new SP name <email> SP time TAB msg LF */3115 if (!sb->len || sb->buf[sb->len - 1] != '\n' ||3116 parse_oid_hex(p, &ooid, &p) || *p++ != ' ' ||3117 parse_oid_hex(p, &noid, &p) || *p++ != ' ' ||3118 !(email_end = strchr(p, '>')) ||3119 email_end[1] != ' ' ||3120 !(timestamp = strtoul(email_end + 2, &message, 10)) ||3121 !message || message[0] != ' ' ||3122 (message[1] != '+' && message[1] != '-') ||3123 !isdigit(message[2]) || !isdigit(message[3]) ||3124 !isdigit(message[4]) || !isdigit(message[5]))3125 return 0; /* corrupt? */3126 email_end[1] = '\0';3127 tz = strtol(message + 1, NULL, 10);3128 if (message[6] != '\t')3129 message += 6;3130 else3131 message += 7;3132 return fn(&ooid, &noid, p, timestamp, tz, message, cb_data);3133}31343135static char *find_beginning_of_line(char *bob, char *scan)3136{3137 while (bob < scan && *(--scan) != '\n')3138 ; /* keep scanning backwards */3139 /*3140 * Return either beginning of the buffer, or LF at the end of3141 * the previous line.3142 */3143 return scan;3144}31453146static int files_for_each_reflog_ent_reverse(struct ref_store *ref_store,3147 const char *refname,3148 each_reflog_ent_fn fn,3149 void *cb_data)3150{3151 struct strbuf sb = STRBUF_INIT;3152 FILE *logfp;3153 long pos;3154 int ret = 0, at_tail = 1;31553156 /* Check validity (but we don't need the result): */3157 files_downcast(ref_store, 0, "for_each_reflog_ent_reverse");31583159 logfp = fopen(git_path("logs/%s", refname), "r");3160 if (!logfp)3161 return -1;31623163 /* Jump to the end */3164 if (fseek(logfp, 0, SEEK_END) < 0)3165 return error("cannot seek back reflog for %s: %s",3166 refname, strerror(errno));3167 pos = ftell(logfp);3168 while (!ret && 0 < pos) {3169 int cnt;3170 size_t nread;3171 char buf[BUFSIZ];3172 char *endp, *scanp;31733174 /* Fill next block from the end */3175 cnt = (sizeof(buf) < pos) ? sizeof(buf) : pos;3176 if (fseek(logfp, pos - cnt, SEEK_SET))3177 return error("cannot seek back reflog for %s: %s",3178 refname, strerror(errno));3179 nread = fread(buf, cnt, 1, logfp);3180 if (nread != 1)3181 return error("cannot read %d bytes from reflog for %s: %s",3182 cnt, refname, strerror(errno));3183 pos -= cnt;31843185 scanp = endp = buf + cnt;3186 if (at_tail && scanp[-1] == '\n')3187 /* Looking at the final LF at the end of the file */3188 scanp--;3189 at_tail = 0;31903191 while (buf < scanp) {3192 /*3193 * terminating LF of the previous line, or the beginning3194 * of the buffer.3195 */3196 char *bp;31973198 bp = find_beginning_of_line(buf, scanp);31993200 if (*bp == '\n') {3201 /*3202 * The newline is the end of the previous line,3203 * so we know we have complete line starting3204 * at (bp + 1). Prefix it onto any prior data3205 * we collected for the line and process it.3206 */3207 strbuf_splice(&sb, 0, 0, bp + 1, endp - (bp + 1));3208 scanp = bp;3209 endp = bp + 1;3210 ret = show_one_reflog_ent(&sb, fn, cb_data);3211 strbuf_reset(&sb);3212 if (ret)3213 break;3214 } else if (!pos) {3215 /*3216 * We are at the start of the buffer, and the3217 * start of the file; there is no previous3218 * line, and we have everything for this one.3219 * Process it, and we can end the loop.3220 */3221 strbuf_splice(&sb, 0, 0, buf, endp - buf);3222 ret = show_one_reflog_ent(&sb, fn, cb_data);3223 strbuf_reset(&sb);3224 break;3225 }32263227 if (bp == buf) {3228 /*3229 * We are at the start of the buffer, and there3230 * is more file to read backwards. Which means3231 * we are in the middle of a line. Note that we3232 * may get here even if *bp was a newline; that3233 * just means we are at the exact end of the3234 * previous line, rather than some spot in the3235 * middle.3236 *3237 * Save away what we have to be combined with3238 * the data from the next read.3239 */3240 strbuf_splice(&sb, 0, 0, buf, endp - buf);3241 break;3242 }3243 }32443245 }3246 if (!ret && sb.len)3247 die("BUG: reverse reflog parser had leftover data");32483249 fclose(logfp);3250 strbuf_release(&sb);3251 return ret;3252}32533254static int files_for_each_reflog_ent(struct ref_store *ref_store,3255 const char *refname,3256 each_reflog_ent_fn fn, void *cb_data)3257{3258 FILE *logfp;3259 struct strbuf sb = STRBUF_INIT;3260 int ret = 0;32613262 /* Check validity (but we don't need the result): */3263 files_downcast(ref_store, 0, "for_each_reflog_ent");32643265 logfp = fopen(git_path("logs/%s", refname), "r");3266 if (!logfp)3267 return -1;32683269 while (!ret && !strbuf_getwholeline(&sb, logfp, '\n'))3270 ret = show_one_reflog_ent(&sb, fn, cb_data);3271 fclose(logfp);3272 strbuf_release(&sb);3273 return ret;3274}32753276struct files_reflog_iterator {3277 struct ref_iterator base;32783279 struct dir_iterator *dir_iterator;3280 struct object_id oid;3281};32823283static int files_reflog_iterator_advance(struct ref_iterator *ref_iterator)3284{3285 struct files_reflog_iterator *iter =3286 (struct files_reflog_iterator *)ref_iterator;3287 struct dir_iterator *diter = iter->dir_iterator;3288 int ok;32893290 while ((ok = dir_iterator_advance(diter)) == ITER_OK) {3291 int flags;32923293 if (!S_ISREG(diter->st.st_mode))3294 continue;3295 if (diter->basename[0] == '.')3296 continue;3297 if (ends_with(diter->basename, ".lock"))3298 continue;32993300 if (read_ref_full(diter->relative_path, 0,3301 iter->oid.hash, &flags)) {3302 error("bad ref for %s", diter->path.buf);3303 continue;3304 }33053306 iter->base.refname = diter->relative_path;3307 iter->base.oid = &iter->oid;3308 iter->base.flags = flags;3309 return ITER_OK;3310 }33113312 iter->dir_iterator = NULL;3313 if (ref_iterator_abort(ref_iterator) == ITER_ERROR)3314 ok = ITER_ERROR;3315 return ok;3316}33173318static int files_reflog_iterator_peel(struct ref_iterator *ref_iterator,3319 struct object_id *peeled)3320{3321 die("BUG: ref_iterator_peel() called for reflog_iterator");3322}33233324static int files_reflog_iterator_abort(struct ref_iterator *ref_iterator)3325{3326 struct files_reflog_iterator *iter =3327 (struct files_reflog_iterator *)ref_iterator;3328 int ok = ITER_DONE;33293330 if (iter->dir_iterator)3331 ok = dir_iterator_abort(iter->dir_iterator);33323333 base_ref_iterator_free(ref_iterator);3334 return ok;3335}33363337static struct ref_iterator_vtable files_reflog_iterator_vtable = {3338 files_reflog_iterator_advance,3339 files_reflog_iterator_peel,3340 files_reflog_iterator_abort3341};33423343static struct ref_iterator *files_reflog_iterator_begin(struct ref_store *ref_store)3344{3345 struct files_reflog_iterator *iter = xcalloc(1, sizeof(*iter));3346 struct ref_iterator *ref_iterator = &iter->base;33473348 /* Check validity (but we don't need the result): */3349 files_downcast(ref_store, 0, "reflog_iterator_begin");33503351 base_ref_iterator_init(ref_iterator, &files_reflog_iterator_vtable);3352 iter->dir_iterator = dir_iterator_begin(git_path("logs"));3353 return ref_iterator;3354}33553356static int ref_update_reject_duplicates(struct string_list *refnames,3357 struct strbuf *err)3358{3359 int i, n = refnames->nr;33603361 assert(err);33623363 for (i = 1; i < n; i++)3364 if (!strcmp(refnames->items[i - 1].string, refnames->items[i].string)) {3365 strbuf_addf(err,3366 "multiple updates for ref '%s' not allowed.",3367 refnames->items[i].string);3368 return 1;3369 }3370 return 0;3371}33723373/*3374 * If update is a direct update of head_ref (the reference pointed to3375 * by HEAD), then add an extra REF_LOG_ONLY update for HEAD.3376 */3377static int split_head_update(struct ref_update *update,3378 struct ref_transaction *transaction,3379 const char *head_ref,3380 struct string_list *affected_refnames,3381 struct strbuf *err)3382{3383 struct string_list_item *item;3384 struct ref_update *new_update;33853386 if ((update->flags & REF_LOG_ONLY) ||3387 (update->flags & REF_ISPRUNING) ||3388 (update->flags & REF_UPDATE_VIA_HEAD))3389 return 0;33903391 if (strcmp(update->refname, head_ref))3392 return 0;33933394 /*3395 * First make sure that HEAD is not already in the3396 * transaction. This insertion is O(N) in the transaction3397 * size, but it happens at most once per transaction.3398 */3399 item = string_list_insert(affected_refnames, "HEAD");3400 if (item->util) {3401 /* An entry already existed */3402 strbuf_addf(err,3403 "multiple updates for 'HEAD' (including one "3404 "via its referent '%s') are not allowed",3405 update->refname);3406 return TRANSACTION_NAME_CONFLICT;3407 }34083409 new_update = ref_transaction_add_update(3410 transaction, "HEAD",3411 update->flags | REF_LOG_ONLY | REF_NODEREF,3412 update->new_sha1, update->old_sha1,3413 update->msg);34143415 item->util = new_update;34163417 return 0;3418}34193420/*3421 * update is for a symref that points at referent and doesn't have3422 * REF_NODEREF set. Split it into two updates:3423 * - The original update, but with REF_LOG_ONLY and REF_NODEREF set3424 * - A new, separate update for the referent reference3425 * Note that the new update will itself be subject to splitting when3426 * the iteration gets to it.3427 */3428static int split_symref_update(struct files_ref_store *refs,3429 struct ref_update *update,3430 const char *referent,3431 struct ref_transaction *transaction,3432 struct string_list *affected_refnames,3433 struct strbuf *err)3434{3435 struct string_list_item *item;3436 struct ref_update *new_update;3437 unsigned int new_flags;34383439 /*3440 * First make sure that referent is not already in the3441 * transaction. This insertion is O(N) in the transaction3442 * size, but it happens at most once per symref in a3443 * transaction.3444 */3445 item = string_list_insert(affected_refnames, referent);3446 if (item->util) {3447 /* An entry already existed */3448 strbuf_addf(err,3449 "multiple updates for '%s' (including one "3450 "via symref '%s') are not allowed",3451 referent, update->refname);3452 return TRANSACTION_NAME_CONFLICT;3453 }34543455 new_flags = update->flags;3456 if (!strcmp(update->refname, "HEAD")) {3457 /*3458 * Record that the new update came via HEAD, so that3459 * when we process it, split_head_update() doesn't try3460 * to add another reflog update for HEAD. Note that3461 * this bit will be propagated if the new_update3462 * itself needs to be split.3463 */3464 new_flags |= REF_UPDATE_VIA_HEAD;3465 }34663467 new_update = ref_transaction_add_update(3468 transaction, referent, new_flags,3469 update->new_sha1, update->old_sha1,3470 update->msg);34713472 new_update->parent_update = update;34733474 /*3475 * Change the symbolic ref update to log only. Also, it3476 * doesn't need to check its old SHA-1 value, as that will be3477 * done when new_update is processed.3478 */3479 update->flags |= REF_LOG_ONLY | REF_NODEREF;3480 update->flags &= ~REF_HAVE_OLD;34813482 item->util = new_update;34833484 return 0;3485}34863487/*3488 * Return the refname under which update was originally requested.3489 */3490static const char *original_update_refname(struct ref_update *update)3491{3492 while (update->parent_update)3493 update = update->parent_update;34943495 return update->refname;3496}34973498/*3499 * Check whether the REF_HAVE_OLD and old_oid values stored in update3500 * are consistent with oid, which is the reference's current value. If3501 * everything is OK, return 0; otherwise, write an error message to3502 * err and return -1.3503 */3504static int check_old_oid(struct ref_update *update, struct object_id *oid,3505 struct strbuf *err)3506{3507 if (!(update->flags & REF_HAVE_OLD) ||3508 !hashcmp(oid->hash, update->old_sha1))3509 return 0;35103511 if (is_null_sha1(update->old_sha1))3512 strbuf_addf(err, "cannot lock ref '%s': "3513 "reference already exists",3514 original_update_refname(update));3515 else if (is_null_oid(oid))3516 strbuf_addf(err, "cannot lock ref '%s': "3517 "reference is missing but expected %s",3518 original_update_refname(update),3519 sha1_to_hex(update->old_sha1));3520 else3521 strbuf_addf(err, "cannot lock ref '%s': "3522 "is at %s but expected %s",3523 original_update_refname(update),3524 oid_to_hex(oid),3525 sha1_to_hex(update->old_sha1));35263527 return -1;3528}35293530/*3531 * Prepare for carrying out update:3532 * - Lock the reference referred to by update.3533 * - Read the reference under lock.3534 * - Check that its old SHA-1 value (if specified) is correct, and in3535 * any case record it in update->lock->old_oid for later use when3536 * writing the reflog.3537 * - If it is a symref update without REF_NODEREF, split it up into a3538 * REF_LOG_ONLY update of the symref and add a separate update for3539 * the referent to transaction.3540 * - If it is an update of head_ref, add a corresponding REF_LOG_ONLY3541 * update of HEAD.3542 */3543static int lock_ref_for_update(struct files_ref_store *refs,3544 struct ref_update *update,3545 struct ref_transaction *transaction,3546 const char *head_ref,3547 struct string_list *affected_refnames,3548 struct strbuf *err)3549{3550 struct strbuf referent = STRBUF_INIT;3551 int mustexist = (update->flags & REF_HAVE_OLD) &&3552 !is_null_sha1(update->old_sha1);3553 int ret;3554 struct ref_lock *lock;35553556 files_assert_main_repository(refs, "lock_ref_for_update");35573558 if ((update->flags & REF_HAVE_NEW) && is_null_sha1(update->new_sha1))3559 update->flags |= REF_DELETING;35603561 if (head_ref) {3562 ret = split_head_update(update, transaction, head_ref,3563 affected_refnames, err);3564 if (ret)3565 return ret;3566 }35673568 ret = lock_raw_ref(refs, update->refname, mustexist,3569 affected_refnames, NULL,3570 &lock, &referent,3571 &update->type, err);3572 if (ret) {3573 char *reason;35743575 reason = strbuf_detach(err, NULL);3576 strbuf_addf(err, "cannot lock ref '%s': %s",3577 original_update_refname(update), reason);3578 free(reason);3579 return ret;3580 }35813582 update->backend_data = lock;35833584 if (update->type & REF_ISSYMREF) {3585 if (update->flags & REF_NODEREF) {3586 /*3587 * We won't be reading the referent as part of3588 * the transaction, so we have to read it here3589 * to record and possibly check old_sha1:3590 */3591 if (read_ref_full(referent.buf, 0,3592 lock->old_oid.hash, NULL)) {3593 if (update->flags & REF_HAVE_OLD) {3594 strbuf_addf(err, "cannot lock ref '%s': "3595 "error reading reference",3596 original_update_refname(update));3597 return -1;3598 }3599 } else if (check_old_oid(update, &lock->old_oid, err)) {3600 return TRANSACTION_GENERIC_ERROR;3601 }3602 } else {3603 /*3604 * Create a new update for the reference this3605 * symref is pointing at. Also, we will record3606 * and verify old_sha1 for this update as part3607 * of processing the split-off update, so we3608 * don't have to do it here.3609 */3610 ret = split_symref_update(refs, update,3611 referent.buf, transaction,3612 affected_refnames, err);3613 if (ret)3614 return ret;3615 }3616 } else {3617 struct ref_update *parent_update;36183619 if (check_old_oid(update, &lock->old_oid, err))3620 return TRANSACTION_GENERIC_ERROR;36213622 /*3623 * If this update is happening indirectly because of a3624 * symref update, record the old SHA-1 in the parent3625 * update:3626 */3627 for (parent_update = update->parent_update;3628 parent_update;3629 parent_update = parent_update->parent_update) {3630 struct ref_lock *parent_lock = parent_update->backend_data;3631 oidcpy(&parent_lock->old_oid, &lock->old_oid);3632 }3633 }36343635 if ((update->flags & REF_HAVE_NEW) &&3636 !(update->flags & REF_DELETING) &&3637 !(update->flags & REF_LOG_ONLY)) {3638 if (!(update->type & REF_ISSYMREF) &&3639 !hashcmp(lock->old_oid.hash, update->new_sha1)) {3640 /*3641 * The reference already has the desired3642 * value, so we don't need to write it.3643 */3644 } else if (write_ref_to_lockfile(lock, update->new_sha1,3645 err)) {3646 char *write_err = strbuf_detach(err, NULL);36473648 /*3649 * The lock was freed upon failure of3650 * write_ref_to_lockfile():3651 */3652 update->backend_data = NULL;3653 strbuf_addf(err,3654 "cannot update ref '%s': %s",3655 update->refname, write_err);3656 free(write_err);3657 return TRANSACTION_GENERIC_ERROR;3658 } else {3659 update->flags |= REF_NEEDS_COMMIT;3660 }3661 }3662 if (!(update->flags & REF_NEEDS_COMMIT)) {3663 /*3664 * We didn't call write_ref_to_lockfile(), so3665 * the lockfile is still open. Close it to3666 * free up the file descriptor:3667 */3668 if (close_ref(lock)) {3669 strbuf_addf(err, "couldn't close '%s.lock'",3670 update->refname);3671 return TRANSACTION_GENERIC_ERROR;3672 }3673 }3674 return 0;3675}36763677static int files_transaction_commit(struct ref_store *ref_store,3678 struct ref_transaction *transaction,3679 struct strbuf *err)3680{3681 struct files_ref_store *refs =3682 files_downcast(ref_store, 0, "ref_transaction_commit");3683 int ret = 0, i;3684 struct string_list refs_to_delete = STRING_LIST_INIT_NODUP;3685 struct string_list_item *ref_to_delete;3686 struct string_list affected_refnames = STRING_LIST_INIT_NODUP;3687 char *head_ref = NULL;3688 int head_type;3689 struct object_id head_oid;36903691 assert(err);36923693 if (transaction->state != REF_TRANSACTION_OPEN)3694 die("BUG: commit called for transaction that is not open");36953696 if (!transaction->nr) {3697 transaction->state = REF_TRANSACTION_CLOSED;3698 return 0;3699 }37003701 /*3702 * Fail if a refname appears more than once in the3703 * transaction. (If we end up splitting up any updates using3704 * split_symref_update() or split_head_update(), those3705 * functions will check that the new updates don't have the3706 * same refname as any existing ones.)3707 */3708 for (i = 0; i < transaction->nr; i++) {3709 struct ref_update *update = transaction->updates[i];3710 struct string_list_item *item =3711 string_list_append(&affected_refnames, update->refname);37123713 /*3714 * We store a pointer to update in item->util, but at3715 * the moment we never use the value of this field3716 * except to check whether it is non-NULL.3717 */3718 item->util = update;3719 }3720 string_list_sort(&affected_refnames);3721 if (ref_update_reject_duplicates(&affected_refnames, err)) {3722 ret = TRANSACTION_GENERIC_ERROR;3723 goto cleanup;3724 }37253726 /*3727 * Special hack: If a branch is updated directly and HEAD3728 * points to it (may happen on the remote side of a push3729 * for example) then logically the HEAD reflog should be3730 * updated too.3731 *3732 * A generic solution would require reverse symref lookups,3733 * but finding all symrefs pointing to a given branch would be3734 * rather costly for this rare event (the direct update of a3735 * branch) to be worth it. So let's cheat and check with HEAD3736 * only, which should cover 99% of all usage scenarios (even3737 * 100% of the default ones).3738 *3739 * So if HEAD is a symbolic reference, then record the name of3740 * the reference that it points to. If we see an update of3741 * head_ref within the transaction, then split_head_update()3742 * arranges for the reflog of HEAD to be updated, too.3743 */3744 head_ref = resolve_refdup("HEAD", RESOLVE_REF_NO_RECURSE,3745 head_oid.hash, &head_type);37463747 if (head_ref && !(head_type & REF_ISSYMREF)) {3748 free(head_ref);3749 head_ref = NULL;3750 }37513752 /*3753 * Acquire all locks, verify old values if provided, check3754 * that new values are valid, and write new values to the3755 * lockfiles, ready to be activated. Only keep one lockfile3756 * open at a time to avoid running out of file descriptors.3757 */3758 for (i = 0; i < transaction->nr; i++) {3759 struct ref_update *update = transaction->updates[i];37603761 ret = lock_ref_for_update(refs, update, transaction,3762 head_ref, &affected_refnames, err);3763 if (ret)3764 goto cleanup;3765 }37663767 /* Perform updates first so live commits remain referenced */3768 for (i = 0; i < transaction->nr; i++) {3769 struct ref_update *update = transaction->updates[i];3770 struct ref_lock *lock = update->backend_data;37713772 if (update->flags & REF_NEEDS_COMMIT ||3773 update->flags & REF_LOG_ONLY) {3774 if (files_log_ref_write(lock->ref_name,3775 lock->old_oid.hash,3776 update->new_sha1,3777 update->msg, update->flags,3778 err)) {3779 char *old_msg = strbuf_detach(err, NULL);37803781 strbuf_addf(err, "cannot update the ref '%s': %s",3782 lock->ref_name, old_msg);3783 free(old_msg);3784 unlock_ref(lock);3785 update->backend_data = NULL;3786 ret = TRANSACTION_GENERIC_ERROR;3787 goto cleanup;3788 }3789 }3790 if (update->flags & REF_NEEDS_COMMIT) {3791 clear_loose_ref_cache(refs);3792 if (commit_ref(lock)) {3793 strbuf_addf(err, "couldn't set '%s'", lock->ref_name);3794 unlock_ref(lock);3795 update->backend_data = NULL;3796 ret = TRANSACTION_GENERIC_ERROR;3797 goto cleanup;3798 }3799 }3800 }3801 /* Perform deletes now that updates are safely completed */3802 for (i = 0; i < transaction->nr; i++) {3803 struct ref_update *update = transaction->updates[i];3804 struct ref_lock *lock = update->backend_data;38053806 if (update->flags & REF_DELETING &&3807 !(update->flags & REF_LOG_ONLY)) {3808 if (!(update->type & REF_ISPACKED) ||3809 update->type & REF_ISSYMREF) {3810 /* It is a loose reference. */3811 if (unlink_or_msg(git_path("%s", lock->ref_name), err)) {3812 ret = TRANSACTION_GENERIC_ERROR;3813 goto cleanup;3814 }3815 update->flags |= REF_DELETED_LOOSE;3816 }38173818 if (!(update->flags & REF_ISPRUNING))3819 string_list_append(&refs_to_delete,3820 lock->ref_name);3821 }3822 }38233824 if (repack_without_refs(refs, &refs_to_delete, err)) {3825 ret = TRANSACTION_GENERIC_ERROR;3826 goto cleanup;3827 }38283829 /* Delete the reflogs of any references that were deleted: */3830 for_each_string_list_item(ref_to_delete, &refs_to_delete) {3831 if (!unlink_or_warn(git_path("logs/%s", ref_to_delete->string)))3832 try_remove_empty_parents(ref_to_delete->string,3833 REMOVE_EMPTY_PARENTS_REFLOG);3834 }38353836 clear_loose_ref_cache(refs);38373838cleanup:3839 transaction->state = REF_TRANSACTION_CLOSED;38403841 for (i = 0; i < transaction->nr; i++) {3842 struct ref_update *update = transaction->updates[i];3843 struct ref_lock *lock = update->backend_data;38443845 if (lock)3846 unlock_ref(lock);38473848 if (update->flags & REF_DELETED_LOOSE) {3849 /*3850 * The loose reference was deleted. Delete any3851 * empty parent directories. (Note that this3852 * can only work because we have already3853 * removed the lockfile.)3854 */3855 try_remove_empty_parents(update->refname,3856 REMOVE_EMPTY_PARENTS_REF);3857 }3858 }38593860 string_list_clear(&refs_to_delete, 0);3861 free(head_ref);3862 string_list_clear(&affected_refnames, 0);38633864 return ret;3865}38663867static int ref_present(const char *refname,3868 const struct object_id *oid, int flags, void *cb_data)3869{3870 struct string_list *affected_refnames = cb_data;38713872 return string_list_has_string(affected_refnames, refname);3873}38743875static int files_initial_transaction_commit(struct ref_store *ref_store,3876 struct ref_transaction *transaction,3877 struct strbuf *err)3878{3879 struct files_ref_store *refs =3880 files_downcast(ref_store, 0, "initial_ref_transaction_commit");3881 int ret = 0, i;3882 struct string_list affected_refnames = STRING_LIST_INIT_NODUP;38833884 assert(err);38853886 if (transaction->state != REF_TRANSACTION_OPEN)3887 die("BUG: commit called for transaction that is not open");38883889 /* Fail if a refname appears more than once in the transaction: */3890 for (i = 0; i < transaction->nr; i++)3891 string_list_append(&affected_refnames,3892 transaction->updates[i]->refname);3893 string_list_sort(&affected_refnames);3894 if (ref_update_reject_duplicates(&affected_refnames, err)) {3895 ret = TRANSACTION_GENERIC_ERROR;3896 goto cleanup;3897 }38983899 /*3900 * It's really undefined to call this function in an active3901 * repository or when there are existing references: we are3902 * only locking and changing packed-refs, so (1) any3903 * simultaneous processes might try to change a reference at3904 * the same time we do, and (2) any existing loose versions of3905 * the references that we are setting would have precedence3906 * over our values. But some remote helpers create the remote3907 * "HEAD" and "master" branches before calling this function,3908 * so here we really only check that none of the references3909 * that we are creating already exists.3910 */3911 if (for_each_rawref(ref_present, &affected_refnames))3912 die("BUG: initial ref transaction called with existing refs");39133914 for (i = 0; i < transaction->nr; i++) {3915 struct ref_update *update = transaction->updates[i];39163917 if ((update->flags & REF_HAVE_OLD) &&3918 !is_null_sha1(update->old_sha1))3919 die("BUG: initial ref transaction with old_sha1 set");3920 if (verify_refname_available(update->refname,3921 &affected_refnames, NULL,3922 err)) {3923 ret = TRANSACTION_NAME_CONFLICT;3924 goto cleanup;3925 }3926 }39273928 if (lock_packed_refs(refs, 0)) {3929 strbuf_addf(err, "unable to lock packed-refs file: %s",3930 strerror(errno));3931 ret = TRANSACTION_GENERIC_ERROR;3932 goto cleanup;3933 }39343935 for (i = 0; i < transaction->nr; i++) {3936 struct ref_update *update = transaction->updates[i];39373938 if ((update->flags & REF_HAVE_NEW) &&3939 !is_null_sha1(update->new_sha1))3940 add_packed_ref(refs, update->refname, update->new_sha1);3941 }39423943 if (commit_packed_refs(refs)) {3944 strbuf_addf(err, "unable to commit packed-refs file: %s",3945 strerror(errno));3946 ret = TRANSACTION_GENERIC_ERROR;3947 goto cleanup;3948 }39493950cleanup:3951 transaction->state = REF_TRANSACTION_CLOSED;3952 string_list_clear(&affected_refnames, 0);3953 return ret;3954}39553956struct expire_reflog_cb {3957 unsigned int flags;3958 reflog_expiry_should_prune_fn *should_prune_fn;3959 void *policy_cb;3960 FILE *newlog;3961 struct object_id last_kept_oid;3962};39633964static int expire_reflog_ent(struct object_id *ooid, struct object_id *noid,3965 const char *email, unsigned long timestamp, int tz,3966 const char *message, void *cb_data)3967{3968 struct expire_reflog_cb *cb = cb_data;3969 struct expire_reflog_policy_cb *policy_cb = cb->policy_cb;39703971 if (cb->flags & EXPIRE_REFLOGS_REWRITE)3972 ooid = &cb->last_kept_oid;39733974 if ((*cb->should_prune_fn)(ooid->hash, noid->hash, email, timestamp, tz,3975 message, policy_cb)) {3976 if (!cb->newlog)3977 printf("would prune %s", message);3978 else if (cb->flags & EXPIRE_REFLOGS_VERBOSE)3979 printf("prune %s", message);3980 } else {3981 if (cb->newlog) {3982 fprintf(cb->newlog, "%s %s %s %lu %+05d\t%s",3983 oid_to_hex(ooid), oid_to_hex(noid),3984 email, timestamp, tz, message);3985 oidcpy(&cb->last_kept_oid, noid);3986 }3987 if (cb->flags & EXPIRE_REFLOGS_VERBOSE)3988 printf("keep %s", message);3989 }3990 return 0;3991}39923993static int files_reflog_expire(struct ref_store *ref_store,3994 const char *refname, const unsigned char *sha1,3995 unsigned int flags,3996 reflog_expiry_prepare_fn prepare_fn,3997 reflog_expiry_should_prune_fn should_prune_fn,3998 reflog_expiry_cleanup_fn cleanup_fn,3999 void *policy_cb_data)4000{4001 struct files_ref_store *refs =4002 files_downcast(ref_store, 0, "reflog_expire");4003 static struct lock_file reflog_lock;4004 struct expire_reflog_cb cb;4005 struct ref_lock *lock;4006 char *log_file;4007 int status = 0;4008 int type;4009 struct strbuf err = STRBUF_INIT;40104011 memset(&cb, 0, sizeof(cb));4012 cb.flags = flags;4013 cb.policy_cb = policy_cb_data;4014 cb.should_prune_fn = should_prune_fn;40154016 /*4017 * The reflog file is locked by holding the lock on the4018 * reference itself, plus we might need to update the4019 * reference if --updateref was specified:4020 */4021 lock = lock_ref_sha1_basic(refs, refname, sha1,4022 NULL, NULL, REF_NODEREF,4023 &type, &err);4024 if (!lock) {4025 error("cannot lock ref '%s': %s", refname, err.buf);4026 strbuf_release(&err);4027 return -1;4028 }4029 if (!reflog_exists(refname)) {4030 unlock_ref(lock);4031 return 0;4032 }40334034 log_file = git_pathdup("logs/%s", refname);4035 if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {4036 /*4037 * Even though holding $GIT_DIR/logs/$reflog.lock has4038 * no locking implications, we use the lock_file4039 * machinery here anyway because it does a lot of the4040 * work we need, including cleaning up if the program4041 * exits unexpectedly.4042 */4043 if (hold_lock_file_for_update(&reflog_lock, log_file, 0) < 0) {4044 struct strbuf err = STRBUF_INIT;4045 unable_to_lock_message(log_file, errno, &err);4046 error("%s", err.buf);4047 strbuf_release(&err);4048 goto failure;4049 }4050 cb.newlog = fdopen_lock_file(&reflog_lock, "w");4051 if (!cb.newlog) {4052 error("cannot fdopen %s (%s)",4053 get_lock_file_path(&reflog_lock), strerror(errno));4054 goto failure;4055 }4056 }40574058 (*prepare_fn)(refname, sha1, cb.policy_cb);4059 for_each_reflog_ent(refname, expire_reflog_ent, &cb);4060 (*cleanup_fn)(cb.policy_cb);40614062 if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {4063 /*4064 * It doesn't make sense to adjust a reference pointed4065 * to by a symbolic ref based on expiring entries in4066 * the symbolic reference's reflog. Nor can we update4067 * a reference if there are no remaining reflog4068 * entries.4069 */4070 int update = (flags & EXPIRE_REFLOGS_UPDATE_REF) &&4071 !(type & REF_ISSYMREF) &&4072 !is_null_oid(&cb.last_kept_oid);40734074 if (close_lock_file(&reflog_lock)) {4075 status |= error("couldn't write %s: %s", log_file,4076 strerror(errno));4077 } else if (update &&4078 (write_in_full(get_lock_file_fd(lock->lk),4079 oid_to_hex(&cb.last_kept_oid), GIT_SHA1_HEXSZ) != GIT_SHA1_HEXSZ ||4080 write_str_in_full(get_lock_file_fd(lock->lk), "\n") != 1 ||4081 close_ref(lock) < 0)) {4082 status |= error("couldn't write %s",4083 get_lock_file_path(lock->lk));4084 rollback_lock_file(&reflog_lock);4085 } else if (commit_lock_file(&reflog_lock)) {4086 status |= error("unable to write reflog '%s' (%s)",4087 log_file, strerror(errno));4088 } else if (update && commit_ref(lock)) {4089 status |= error("couldn't set %s", lock->ref_name);4090 }4091 }4092 free(log_file);4093 unlock_ref(lock);4094 return status;40954096 failure:4097 rollback_lock_file(&reflog_lock);4098 free(log_file);4099 unlock_ref(lock);4100 return -1;4101}41024103static int files_init_db(struct ref_store *ref_store, struct strbuf *err)4104{4105 /* Check validity (but we don't need the result): */4106 files_downcast(ref_store, 0, "init_db");41074108 /*4109 * Create .git/refs/{heads,tags}4110 */4111 safe_create_dir(git_path("refs/heads"), 1);4112 safe_create_dir(git_path("refs/tags"), 1);4113 if (get_shared_repository()) {4114 adjust_shared_perm(git_path("refs/heads"));4115 adjust_shared_perm(git_path("refs/tags"));4116 }4117 return 0;4118}41194120struct ref_storage_be refs_be_files = {4121 NULL,4122 "files",4123 files_ref_store_create,4124 files_init_db,4125 files_transaction_commit,4126 files_initial_transaction_commit,41274128 files_pack_refs,4129 files_peel_ref,4130 files_create_symref,4131 files_delete_refs,4132 files_rename_ref,41334134 files_ref_iterator_begin,4135 files_read_raw_ref,4136 files_verify_refname_available,41374138 files_reflog_iterator_begin,4139 files_for_each_reflog_ent,4140 files_for_each_reflog_ent_reverse,4141 files_reflog_exists,4142 files_create_reflog,4143 files_delete_reflog,4144 files_reflog_expire4145};