1#include "../cache.h" 2#include "../refs.h" 3#include "refs-internal.h" 4#include "../lockfile.h" 5#include "../object.h" 6#include "../dir.h" 7 8struct ref_lock { 9 char *ref_name; 10 char *orig_ref_name; 11 struct lock_file *lk; 12 struct object_id old_oid; 13}; 14 15struct ref_entry; 16 17/* 18 * Information used (along with the information in ref_entry) to 19 * describe a single cached reference. This data structure only 20 * occurs embedded in a union in struct ref_entry, and only when 21 * (ref_entry->flag & REF_DIR) is zero. 22 */ 23struct ref_value { 24 /* 25 * The name of the object to which this reference resolves 26 * (which may be a tag object). If REF_ISBROKEN, this is 27 * null. If REF_ISSYMREF, then this is the name of the object 28 * referred to by the last reference in the symlink chain. 29 */ 30 struct object_id oid; 31 32 /* 33 * If REF_KNOWS_PEELED, then this field holds the peeled value 34 * of this reference, or null if the reference is known not to 35 * be peelable. See the documentation for peel_ref() for an 36 * exact definition of "peelable". 37 */ 38 struct object_id peeled; 39}; 40 41struct ref_cache; 42 43/* 44 * Information used (along with the information in ref_entry) to 45 * describe a level in the hierarchy of references. This data 46 * structure only occurs embedded in a union in struct ref_entry, and 47 * only when (ref_entry.flag & REF_DIR) is set. In that case, 48 * (ref_entry.flag & REF_INCOMPLETE) determines whether the references 49 * in the directory have already been read: 50 * 51 * (ref_entry.flag & REF_INCOMPLETE) unset -- a directory of loose 52 * or packed references, already read. 53 * 54 * (ref_entry.flag & REF_INCOMPLETE) set -- a directory of loose 55 * references that hasn't been read yet (nor has any of its 56 * subdirectories). 57 * 58 * Entries within a directory are stored within a growable array of 59 * pointers to ref_entries (entries, nr, alloc). Entries 0 <= i < 60 * sorted are sorted by their component name in strcmp() order and the 61 * remaining entries are unsorted. 62 * 63 * Loose references are read lazily, one directory at a time. When a 64 * directory of loose references is read, then all of the references 65 * in that directory are stored, and REF_INCOMPLETE stubs are created 66 * for any subdirectories, but the subdirectories themselves are not 67 * read. The reading is triggered by get_ref_dir(). 68 */ 69struct ref_dir { 70 int nr, alloc; 71 72 /* 73 * Entries with index 0 <= i < sorted are sorted by name. New 74 * entries are appended to the list unsorted, and are sorted 75 * only when required; thus we avoid the need to sort the list 76 * after the addition of every reference. 77 */ 78 int sorted; 79 80 /* A pointer to the ref_cache that contains this ref_dir. */ 81 struct ref_cache *ref_cache; 82 83 struct ref_entry **entries; 84}; 85 86/* 87 * Bit values for ref_entry::flag. REF_ISSYMREF=0x01, 88 * REF_ISPACKED=0x02, REF_ISBROKEN=0x04 and REF_BAD_NAME=0x08 are 89 * public values; see refs.h. 90 */ 91 92/* 93 * The field ref_entry->u.value.peeled of this value entry contains 94 * the correct peeled value for the reference, which might be 95 * null_sha1 if the reference is not a tag or if it is broken. 96 */ 97#define REF_KNOWS_PEELED 0x10 98 99/* ref_entry represents a directory of references */ 100#define REF_DIR 0x20 101 102/* 103 * Entry has not yet been read from disk (used only for REF_DIR 104 * entries representing loose references) 105 */ 106#define REF_INCOMPLETE 0x40 107 108/* 109 * A ref_entry represents either a reference or a "subdirectory" of 110 * references. 111 * 112 * Each directory in the reference namespace is represented by a 113 * ref_entry with (flags & REF_DIR) set and containing a subdir member 114 * that holds the entries in that directory that have been read so 115 * far. If (flags & REF_INCOMPLETE) is set, then the directory and 116 * its subdirectories haven't been read yet. REF_INCOMPLETE is only 117 * used for loose reference directories. 118 * 119 * References are represented by a ref_entry with (flags & REF_DIR) 120 * unset and a value member that describes the reference's value. The 121 * flag member is at the ref_entry level, but it is also needed to 122 * interpret the contents of the value field (in other words, a 123 * ref_value object is not very much use without the enclosing 124 * ref_entry). 125 * 126 * Reference names cannot end with slash and directories' names are 127 * always stored with a trailing slash (except for the top-level 128 * directory, which is always denoted by ""). This has two nice 129 * consequences: (1) when the entries in each subdir are sorted 130 * lexicographically by name (as they usually are), the references in 131 * a whole tree can be generated in lexicographic order by traversing 132 * the tree in left-to-right, depth-first order; (2) the names of 133 * references and subdirectories cannot conflict, and therefore the 134 * presence of an empty subdirectory does not block the creation of a 135 * similarly-named reference. (The fact that reference names with the 136 * same leading components can conflict *with each other* is a 137 * separate issue that is regulated by verify_refname_available().) 138 * 139 * Please note that the name field contains the fully-qualified 140 * reference (or subdirectory) name. Space could be saved by only 141 * storing the relative names. But that would require the full names 142 * to be generated on the fly when iterating in do_for_each_ref(), and 143 * would break callback functions, who have always been able to assume 144 * that the name strings that they are passed will not be freed during 145 * the iteration. 146 */ 147struct ref_entry { 148 unsigned char flag; /* ISSYMREF? ISPACKED? */ 149 union { 150 struct ref_value value; /* if not (flags&REF_DIR) */ 151 struct ref_dir subdir; /* if (flags&REF_DIR) */ 152 } u; 153 /* 154 * The full name of the reference (e.g., "refs/heads/master") 155 * or the full name of the directory with a trailing slash 156 * (e.g., "refs/heads/"): 157 */ 158 char name[FLEX_ARRAY]; 159}; 160 161static void read_loose_refs(const char *dirname, struct ref_dir *dir); 162static int search_ref_dir(struct ref_dir *dir, const char *refname, size_t len); 163static struct ref_entry *create_dir_entry(struct ref_cache *ref_cache, 164 const char *dirname, size_t len, 165 int incomplete); 166static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry); 167 168static struct ref_dir *get_ref_dir(struct ref_entry *entry) 169{ 170 struct ref_dir *dir; 171 assert(entry->flag & REF_DIR); 172 dir = &entry->u.subdir; 173 if (entry->flag & REF_INCOMPLETE) { 174 read_loose_refs(entry->name, dir); 175 176 /* 177 * Manually add refs/bisect, which, being 178 * per-worktree, might not appear in the directory 179 * listing for refs/ in the main repo. 180 */ 181 if (!strcmp(entry->name, "refs/")) { 182 int pos = search_ref_dir(dir, "refs/bisect/", 12); 183 if (pos < 0) { 184 struct ref_entry *child_entry; 185 child_entry = create_dir_entry(dir->ref_cache, 186 "refs/bisect/", 187 12, 1); 188 add_entry_to_dir(dir, child_entry); 189 read_loose_refs("refs/bisect", 190 &child_entry->u.subdir); 191 } 192 } 193 entry->flag &= ~REF_INCOMPLETE; 194 } 195 return dir; 196} 197 198static struct ref_entry *create_ref_entry(const char *refname, 199 const unsigned char *sha1, int flag, 200 int check_name) 201{ 202 struct ref_entry *ref; 203 204 if (check_name && 205 check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) 206 die("Reference has invalid format: '%s'", refname); 207 FLEX_ALLOC_STR(ref, name, refname); 208 hashcpy(ref->u.value.oid.hash, sha1); 209 oidclr(&ref->u.value.peeled); 210 ref->flag = flag; 211 return ref; 212} 213 214static void clear_ref_dir(struct ref_dir *dir); 215 216static void free_ref_entry(struct ref_entry *entry) 217{ 218 if (entry->flag & REF_DIR) { 219 /* 220 * Do not use get_ref_dir() here, as that might 221 * trigger the reading of loose refs. 222 */ 223 clear_ref_dir(&entry->u.subdir); 224 } 225 free(entry); 226} 227 228/* 229 * Add a ref_entry to the end of dir (unsorted). Entry is always 230 * stored directly in dir; no recursion into subdirectories is 231 * done. 232 */ 233static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry) 234{ 235 ALLOC_GROW(dir->entries, dir->nr + 1, dir->alloc); 236 dir->entries[dir->nr++] = entry; 237 /* optimize for the case that entries are added in order */ 238 if (dir->nr == 1 || 239 (dir->nr == dir->sorted + 1 && 240 strcmp(dir->entries[dir->nr - 2]->name, 241 dir->entries[dir->nr - 1]->name) < 0)) 242 dir->sorted = dir->nr; 243} 244 245/* 246 * Clear and free all entries in dir, recursively. 247 */ 248static void clear_ref_dir(struct ref_dir *dir) 249{ 250 int i; 251 for (i = 0; i < dir->nr; i++) 252 free_ref_entry(dir->entries[i]); 253 free(dir->entries); 254 dir->sorted = dir->nr = dir->alloc = 0; 255 dir->entries = NULL; 256} 257 258/* 259 * Create a struct ref_entry object for the specified dirname. 260 * dirname is the name of the directory with a trailing slash (e.g., 261 * "refs/heads/") or "" for the top-level directory. 262 */ 263static struct ref_entry *create_dir_entry(struct ref_cache *ref_cache, 264 const char *dirname, size_t len, 265 int incomplete) 266{ 267 struct ref_entry *direntry; 268 FLEX_ALLOC_MEM(direntry, name, dirname, len); 269 direntry->u.subdir.ref_cache = ref_cache; 270 direntry->flag = REF_DIR | (incomplete ? REF_INCOMPLETE : 0); 271 return direntry; 272} 273 274static int ref_entry_cmp(const void *a, const void *b) 275{ 276 struct ref_entry *one = *(struct ref_entry **)a; 277 struct ref_entry *two = *(struct ref_entry **)b; 278 return strcmp(one->name, two->name); 279} 280 281static void sort_ref_dir(struct ref_dir *dir); 282 283struct string_slice { 284 size_t len; 285 const char *str; 286}; 287 288static int ref_entry_cmp_sslice(const void *key_, const void *ent_) 289{ 290 const struct string_slice *key = key_; 291 const struct ref_entry *ent = *(const struct ref_entry * const *)ent_; 292 int cmp = strncmp(key->str, ent->name, key->len); 293 if (cmp) 294 return cmp; 295 return '\0' - (unsigned char)ent->name[key->len]; 296} 297 298/* 299 * Return the index of the entry with the given refname from the 300 * ref_dir (non-recursively), sorting dir if necessary. Return -1 if 301 * no such entry is found. dir must already be complete. 302 */ 303static int search_ref_dir(struct ref_dir *dir, const char *refname, size_t len) 304{ 305 struct ref_entry **r; 306 struct string_slice key; 307 308 if (refname == NULL || !dir->nr) 309 return -1; 310 311 sort_ref_dir(dir); 312 key.len = len; 313 key.str = refname; 314 r = bsearch(&key, dir->entries, dir->nr, sizeof(*dir->entries), 315 ref_entry_cmp_sslice); 316 317 if (r == NULL) 318 return -1; 319 320 return r - dir->entries; 321} 322 323/* 324 * Search for a directory entry directly within dir (without 325 * recursing). Sort dir if necessary. subdirname must be a directory 326 * name (i.e., end in '/'). If mkdir is set, then create the 327 * directory if it is missing; otherwise, return NULL if the desired 328 * directory cannot be found. dir must already be complete. 329 */ 330static struct ref_dir *search_for_subdir(struct ref_dir *dir, 331 const char *subdirname, size_t len, 332 int mkdir) 333{ 334 int entry_index = search_ref_dir(dir, subdirname, len); 335 struct ref_entry *entry; 336 if (entry_index == -1) { 337 if (!mkdir) 338 return NULL; 339 /* 340 * Since dir is complete, the absence of a subdir 341 * means that the subdir really doesn't exist; 342 * therefore, create an empty record for it but mark 343 * the record complete. 344 */ 345 entry = create_dir_entry(dir->ref_cache, subdirname, len, 0); 346 add_entry_to_dir(dir, entry); 347 } else { 348 entry = dir->entries[entry_index]; 349 } 350 return get_ref_dir(entry); 351} 352 353/* 354 * If refname is a reference name, find the ref_dir within the dir 355 * tree that should hold refname. If refname is a directory name 356 * (i.e., ends in '/'), then return that ref_dir itself. dir must 357 * represent the top-level directory and must already be complete. 358 * Sort ref_dirs and recurse into subdirectories as necessary. If 359 * mkdir is set, then create any missing directories; otherwise, 360 * return NULL if the desired directory cannot be found. 361 */ 362static struct ref_dir *find_containing_dir(struct ref_dir *dir, 363 const char *refname, int mkdir) 364{ 365 const char *slash; 366 for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) { 367 size_t dirnamelen = slash - refname + 1; 368 struct ref_dir *subdir; 369 subdir = search_for_subdir(dir, refname, dirnamelen, mkdir); 370 if (!subdir) { 371 dir = NULL; 372 break; 373 } 374 dir = subdir; 375 } 376 377 return dir; 378} 379 380/* 381 * Find the value entry with the given name in dir, sorting ref_dirs 382 * and recursing into subdirectories as necessary. If the name is not 383 * found or it corresponds to a directory entry, return NULL. 384 */ 385static struct ref_entry *find_ref(struct ref_dir *dir, const char *refname) 386{ 387 int entry_index; 388 struct ref_entry *entry; 389 dir = find_containing_dir(dir, refname, 0); 390 if (!dir) 391 return NULL; 392 entry_index = search_ref_dir(dir, refname, strlen(refname)); 393 if (entry_index == -1) 394 return NULL; 395 entry = dir->entries[entry_index]; 396 return (entry->flag & REF_DIR) ? NULL : entry; 397} 398 399/* 400 * Remove the entry with the given name from dir, recursing into 401 * subdirectories as necessary. If refname is the name of a directory 402 * (i.e., ends with '/'), then remove the directory and its contents. 403 * If the removal was successful, return the number of entries 404 * remaining in the directory entry that contained the deleted entry. 405 * If the name was not found, return -1. Please note that this 406 * function only deletes the entry from the cache; it does not delete 407 * it from the filesystem or ensure that other cache entries (which 408 * might be symbolic references to the removed entry) are updated. 409 * Nor does it remove any containing dir entries that might be made 410 * empty by the removal. dir must represent the top-level directory 411 * and must already be complete. 412 */ 413static int remove_entry(struct ref_dir *dir, const char *refname) 414{ 415 int refname_len = strlen(refname); 416 int entry_index; 417 struct ref_entry *entry; 418 int is_dir = refname[refname_len - 1] == '/'; 419 if (is_dir) { 420 /* 421 * refname represents a reference directory. Remove 422 * the trailing slash; otherwise we will get the 423 * directory *representing* refname rather than the 424 * one *containing* it. 425 */ 426 char *dirname = xmemdupz(refname, refname_len - 1); 427 dir = find_containing_dir(dir, dirname, 0); 428 free(dirname); 429 } else { 430 dir = find_containing_dir(dir, refname, 0); 431 } 432 if (!dir) 433 return -1; 434 entry_index = search_ref_dir(dir, refname, refname_len); 435 if (entry_index == -1) 436 return -1; 437 entry = dir->entries[entry_index]; 438 439 memmove(&dir->entries[entry_index], 440 &dir->entries[entry_index + 1], 441 (dir->nr - entry_index - 1) * sizeof(*dir->entries) 442 ); 443 dir->nr--; 444 if (dir->sorted > entry_index) 445 dir->sorted--; 446 free_ref_entry(entry); 447 return dir->nr; 448} 449 450/* 451 * Add a ref_entry to the ref_dir (unsorted), recursing into 452 * subdirectories as necessary. dir must represent the top-level 453 * directory. Return 0 on success. 454 */ 455static int add_ref(struct ref_dir *dir, struct ref_entry *ref) 456{ 457 dir = find_containing_dir(dir, ref->name, 1); 458 if (!dir) 459 return -1; 460 add_entry_to_dir(dir, ref); 461 return 0; 462} 463 464/* 465 * Emit a warning and return true iff ref1 and ref2 have the same name 466 * and the same sha1. Die if they have the same name but different 467 * sha1s. 468 */ 469static int is_dup_ref(const struct ref_entry *ref1, const struct ref_entry *ref2) 470{ 471 if (strcmp(ref1->name, ref2->name)) 472 return 0; 473 474 /* Duplicate name; make sure that they don't conflict: */ 475 476 if ((ref1->flag & REF_DIR) || (ref2->flag & REF_DIR)) 477 /* This is impossible by construction */ 478 die("Reference directory conflict: %s", ref1->name); 479 480 if (oidcmp(&ref1->u.value.oid, &ref2->u.value.oid)) 481 die("Duplicated ref, and SHA1s don't match: %s", ref1->name); 482 483 warning("Duplicated ref: %s", ref1->name); 484 return 1; 485} 486 487/* 488 * Sort the entries in dir non-recursively (if they are not already 489 * sorted) and remove any duplicate entries. 490 */ 491static void sort_ref_dir(struct ref_dir *dir) 492{ 493 int i, j; 494 struct ref_entry *last = NULL; 495 496 /* 497 * This check also prevents passing a zero-length array to qsort(), 498 * which is a problem on some platforms. 499 */ 500 if (dir->sorted == dir->nr) 501 return; 502 503 qsort(dir->entries, dir->nr, sizeof(*dir->entries), ref_entry_cmp); 504 505 /* Remove any duplicates: */ 506 for (i = 0, j = 0; j < dir->nr; j++) { 507 struct ref_entry *entry = dir->entries[j]; 508 if (last && is_dup_ref(last, entry)) 509 free_ref_entry(entry); 510 else 511 last = dir->entries[i++] = entry; 512 } 513 dir->sorted = dir->nr = i; 514} 515 516/* 517 * Return true iff the reference described by entry can be resolved to 518 * an object in the database. Emit a warning if the referred-to 519 * object does not exist. 520 */ 521static int ref_resolves_to_object(struct ref_entry *entry) 522{ 523 if (entry->flag & REF_ISBROKEN) 524 return 0; 525 if (!has_sha1_file(entry->u.value.oid.hash)) { 526 error("%s does not point to a valid object!", entry->name); 527 return 0; 528 } 529 return 1; 530} 531 532/* 533 * current_ref is a performance hack: when iterating over references 534 * using the for_each_ref*() functions, current_ref is set to the 535 * current reference's entry before calling the callback function. If 536 * the callback function calls peel_ref(), then peel_ref() first 537 * checks whether the reference to be peeled is the current reference 538 * (it usually is) and if so, returns that reference's peeled version 539 * if it is available. This avoids a refname lookup in a common case. 540 */ 541static struct ref_entry *current_ref; 542 543typedef int each_ref_entry_fn(struct ref_entry *entry, void *cb_data); 544 545struct ref_entry_cb { 546 const char *base; 547 int trim; 548 int flags; 549 each_ref_fn *fn; 550 void *cb_data; 551}; 552 553/* 554 * Handle one reference in a do_for_each_ref*()-style iteration, 555 * calling an each_ref_fn for each entry. 556 */ 557static int do_one_ref(struct ref_entry *entry, void *cb_data) 558{ 559 struct ref_entry_cb *data = cb_data; 560 struct ref_entry *old_current_ref; 561 int retval; 562 563 if (!starts_with(entry->name, data->base)) 564 return 0; 565 566 if (!(data->flags & DO_FOR_EACH_INCLUDE_BROKEN) && 567 !ref_resolves_to_object(entry)) 568 return 0; 569 570 /* Store the old value, in case this is a recursive call: */ 571 old_current_ref = current_ref; 572 current_ref = entry; 573 retval = data->fn(entry->name + data->trim, &entry->u.value.oid, 574 entry->flag, data->cb_data); 575 current_ref = old_current_ref; 576 return retval; 577} 578 579/* 580 * Call fn for each reference in dir that has index in the range 581 * offset <= index < dir->nr. Recurse into subdirectories that are in 582 * that index range, sorting them before iterating. This function 583 * does not sort dir itself; it should be sorted beforehand. fn is 584 * called for all references, including broken ones. 585 */ 586static int do_for_each_entry_in_dir(struct ref_dir *dir, int offset, 587 each_ref_entry_fn fn, void *cb_data) 588{ 589 int i; 590 assert(dir->sorted == dir->nr); 591 for (i = offset; i < dir->nr; i++) { 592 struct ref_entry *entry = dir->entries[i]; 593 int retval; 594 if (entry->flag & REF_DIR) { 595 struct ref_dir *subdir = get_ref_dir(entry); 596 sort_ref_dir(subdir); 597 retval = do_for_each_entry_in_dir(subdir, 0, fn, cb_data); 598 } else { 599 retval = fn(entry, cb_data); 600 } 601 if (retval) 602 return retval; 603 } 604 return 0; 605} 606 607/* 608 * Call fn for each reference in the union of dir1 and dir2, in order 609 * by refname. Recurse into subdirectories. If a value entry appears 610 * in both dir1 and dir2, then only process the version that is in 611 * dir2. The input dirs must already be sorted, but subdirs will be 612 * sorted as needed. fn is called for all references, including 613 * broken ones. 614 */ 615static int do_for_each_entry_in_dirs(struct ref_dir *dir1, 616 struct ref_dir *dir2, 617 each_ref_entry_fn fn, void *cb_data) 618{ 619 int retval; 620 int i1 = 0, i2 = 0; 621 622 assert(dir1->sorted == dir1->nr); 623 assert(dir2->sorted == dir2->nr); 624 while (1) { 625 struct ref_entry *e1, *e2; 626 int cmp; 627 if (i1 == dir1->nr) { 628 return do_for_each_entry_in_dir(dir2, i2, fn, cb_data); 629 } 630 if (i2 == dir2->nr) { 631 return do_for_each_entry_in_dir(dir1, i1, fn, cb_data); 632 } 633 e1 = dir1->entries[i1]; 634 e2 = dir2->entries[i2]; 635 cmp = strcmp(e1->name, e2->name); 636 if (cmp == 0) { 637 if ((e1->flag & REF_DIR) && (e2->flag & REF_DIR)) { 638 /* Both are directories; descend them in parallel. */ 639 struct ref_dir *subdir1 = get_ref_dir(e1); 640 struct ref_dir *subdir2 = get_ref_dir(e2); 641 sort_ref_dir(subdir1); 642 sort_ref_dir(subdir2); 643 retval = do_for_each_entry_in_dirs( 644 subdir1, subdir2, fn, cb_data); 645 i1++; 646 i2++; 647 } else if (!(e1->flag & REF_DIR) && !(e2->flag & REF_DIR)) { 648 /* Both are references; ignore the one from dir1. */ 649 retval = fn(e2, cb_data); 650 i1++; 651 i2++; 652 } else { 653 die("conflict between reference and directory: %s", 654 e1->name); 655 } 656 } else { 657 struct ref_entry *e; 658 if (cmp < 0) { 659 e = e1; 660 i1++; 661 } else { 662 e = e2; 663 i2++; 664 } 665 if (e->flag & REF_DIR) { 666 struct ref_dir *subdir = get_ref_dir(e); 667 sort_ref_dir(subdir); 668 retval = do_for_each_entry_in_dir( 669 subdir, 0, fn, cb_data); 670 } else { 671 retval = fn(e, cb_data); 672 } 673 } 674 if (retval) 675 return retval; 676 } 677} 678 679/* 680 * Load all of the refs from the dir into our in-memory cache. The hard work 681 * of loading loose refs is done by get_ref_dir(), so we just need to recurse 682 * through all of the sub-directories. We do not even need to care about 683 * sorting, as traversal order does not matter to us. 684 */ 685static void prime_ref_dir(struct ref_dir *dir) 686{ 687 int i; 688 for (i = 0; i < dir->nr; i++) { 689 struct ref_entry *entry = dir->entries[i]; 690 if (entry->flag & REF_DIR) 691 prime_ref_dir(get_ref_dir(entry)); 692 } 693} 694 695struct nonmatching_ref_data { 696 const struct string_list *skip; 697 const char *conflicting_refname; 698}; 699 700static int nonmatching_ref_fn(struct ref_entry *entry, void *vdata) 701{ 702 struct nonmatching_ref_data *data = vdata; 703 704 if (data->skip && string_list_has_string(data->skip, entry->name)) 705 return 0; 706 707 data->conflicting_refname = entry->name; 708 return 1; 709} 710 711/* 712 * Return 0 if a reference named refname could be created without 713 * conflicting with the name of an existing reference in dir. 714 * See verify_refname_available for more information. 715 */ 716static int verify_refname_available_dir(const char *refname, 717 const struct string_list *extras, 718 const struct string_list *skip, 719 struct ref_dir *dir, 720 struct strbuf *err) 721{ 722 const char *slash; 723 const char *extra_refname; 724 int pos; 725 struct strbuf dirname = STRBUF_INIT; 726 int ret = -1; 727 728 /* 729 * For the sake of comments in this function, suppose that 730 * refname is "refs/foo/bar". 731 */ 732 733 assert(err); 734 735 strbuf_grow(&dirname, strlen(refname) + 1); 736 for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) { 737 /* Expand dirname to the new prefix, not including the trailing slash: */ 738 strbuf_add(&dirname, refname + dirname.len, slash - refname - dirname.len); 739 740 /* 741 * We are still at a leading dir of the refname (e.g., 742 * "refs/foo"; if there is a reference with that name, 743 * it is a conflict, *unless* it is in skip. 744 */ 745 if (dir) { 746 pos = search_ref_dir(dir, dirname.buf, dirname.len); 747 if (pos >= 0 && 748 (!skip || !string_list_has_string(skip, dirname.buf))) { 749 /* 750 * We found a reference whose name is 751 * a proper prefix of refname; e.g., 752 * "refs/foo", and is not in skip. 753 */ 754 strbuf_addf(err, "'%s' exists; cannot create '%s'", 755 dirname.buf, refname); 756 goto cleanup; 757 } 758 } 759 760 if (extras && string_list_has_string(extras, dirname.buf) && 761 (!skip || !string_list_has_string(skip, dirname.buf))) { 762 strbuf_addf(err, "cannot process '%s' and '%s' at the same time", 763 refname, dirname.buf); 764 goto cleanup; 765 } 766 767 /* 768 * Otherwise, we can try to continue our search with 769 * the next component. So try to look up the 770 * directory, e.g., "refs/foo/". If we come up empty, 771 * we know there is nothing under this whole prefix, 772 * but even in that case we still have to continue the 773 * search for conflicts with extras. 774 */ 775 strbuf_addch(&dirname, '/'); 776 if (dir) { 777 pos = search_ref_dir(dir, dirname.buf, dirname.len); 778 if (pos < 0) { 779 /* 780 * There was no directory "refs/foo/", 781 * so there is nothing under this 782 * whole prefix. So there is no need 783 * to continue looking for conflicting 784 * references. But we need to continue 785 * looking for conflicting extras. 786 */ 787 dir = NULL; 788 } else { 789 dir = get_ref_dir(dir->entries[pos]); 790 } 791 } 792 } 793 794 /* 795 * We are at the leaf of our refname (e.g., "refs/foo/bar"). 796 * There is no point in searching for a reference with that 797 * name, because a refname isn't considered to conflict with 798 * itself. But we still need to check for references whose 799 * names are in the "refs/foo/bar/" namespace, because they 800 * *do* conflict. 801 */ 802 strbuf_addstr(&dirname, refname + dirname.len); 803 strbuf_addch(&dirname, '/'); 804 805 if (dir) { 806 pos = search_ref_dir(dir, dirname.buf, dirname.len); 807 808 if (pos >= 0) { 809 /* 810 * We found a directory named "$refname/" 811 * (e.g., "refs/foo/bar/"). It is a problem 812 * iff it contains any ref that is not in 813 * "skip". 814 */ 815 struct nonmatching_ref_data data; 816 817 data.skip = skip; 818 data.conflicting_refname = NULL; 819 dir = get_ref_dir(dir->entries[pos]); 820 sort_ref_dir(dir); 821 if (do_for_each_entry_in_dir(dir, 0, nonmatching_ref_fn, &data)) { 822 strbuf_addf(err, "'%s' exists; cannot create '%s'", 823 data.conflicting_refname, refname); 824 goto cleanup; 825 } 826 } 827 } 828 829 extra_refname = find_descendant_ref(dirname.buf, extras, skip); 830 if (extra_refname) 831 strbuf_addf(err, "cannot process '%s' and '%s' at the same time", 832 refname, extra_refname); 833 else 834 ret = 0; 835 836cleanup: 837 strbuf_release(&dirname); 838 return ret; 839} 840 841struct packed_ref_cache { 842 struct ref_entry *root; 843 844 /* 845 * Count of references to the data structure in this instance, 846 * including the pointer from ref_cache::packed if any. The 847 * data will not be freed as long as the reference count is 848 * nonzero. 849 */ 850 unsigned int referrers; 851 852 /* 853 * Iff the packed-refs file associated with this instance is 854 * currently locked for writing, this points at the associated 855 * lock (which is owned by somebody else). The referrer count 856 * is also incremented when the file is locked and decremented 857 * when it is unlocked. 858 */ 859 struct lock_file *lock; 860 861 /* The metadata from when this packed-refs cache was read */ 862 struct stat_validity validity; 863}; 864 865/* 866 * Future: need to be in "struct repository" 867 * when doing a full libification. 868 */ 869static struct ref_cache { 870 struct ref_cache *next; 871 struct ref_entry *loose; 872 struct packed_ref_cache *packed; 873 /* 874 * The submodule name, or "" for the main repo. We allocate 875 * length 1 rather than FLEX_ARRAY so that the main ref_cache 876 * is initialized correctly. 877 */ 878 char name[1]; 879} ref_cache, *submodule_ref_caches; 880 881/* Lock used for the main packed-refs file: */ 882static struct lock_file packlock; 883 884/* 885 * Increment the reference count of *packed_refs. 886 */ 887static void acquire_packed_ref_cache(struct packed_ref_cache *packed_refs) 888{ 889 packed_refs->referrers++; 890} 891 892/* 893 * Decrease the reference count of *packed_refs. If it goes to zero, 894 * free *packed_refs and return true; otherwise return false. 895 */ 896static int release_packed_ref_cache(struct packed_ref_cache *packed_refs) 897{ 898 if (!--packed_refs->referrers) { 899 free_ref_entry(packed_refs->root); 900 stat_validity_clear(&packed_refs->validity); 901 free(packed_refs); 902 return 1; 903 } else { 904 return 0; 905 } 906} 907 908static void clear_packed_ref_cache(struct ref_cache *refs) 909{ 910 if (refs->packed) { 911 struct packed_ref_cache *packed_refs = refs->packed; 912 913 if (packed_refs->lock) 914 die("internal error: packed-ref cache cleared while locked"); 915 refs->packed = NULL; 916 release_packed_ref_cache(packed_refs); 917 } 918} 919 920static void clear_loose_ref_cache(struct ref_cache *refs) 921{ 922 if (refs->loose) { 923 free_ref_entry(refs->loose); 924 refs->loose = NULL; 925 } 926} 927 928/* 929 * Create a new submodule ref cache and add it to the internal 930 * set of caches. 931 */ 932static struct ref_cache *create_ref_cache(const char *submodule) 933{ 934 struct ref_cache *refs; 935 if (!submodule) 936 submodule = ""; 937 FLEX_ALLOC_STR(refs, name, submodule); 938 refs->next = submodule_ref_caches; 939 submodule_ref_caches = refs; 940 return refs; 941} 942 943static struct ref_cache *lookup_ref_cache(const char *submodule) 944{ 945 struct ref_cache *refs; 946 947 if (!submodule || !*submodule) 948 return &ref_cache; 949 950 for (refs = submodule_ref_caches; refs; refs = refs->next) 951 if (!strcmp(submodule, refs->name)) 952 return refs; 953 return NULL; 954} 955 956/* 957 * Return a pointer to a ref_cache for the specified submodule. For 958 * the main repository, use submodule==NULL. The returned structure 959 * will be allocated and initialized but not necessarily populated; it 960 * should not be freed. 961 */ 962static struct ref_cache *get_ref_cache(const char *submodule) 963{ 964 struct ref_cache *refs = lookup_ref_cache(submodule); 965 if (!refs) 966 refs = create_ref_cache(submodule); 967 return refs; 968} 969 970/* The length of a peeled reference line in packed-refs, including EOL: */ 971#define PEELED_LINE_LENGTH 42 972 973/* 974 * The packed-refs header line that we write out. Perhaps other 975 * traits will be added later. The trailing space is required. 976 */ 977static const char PACKED_REFS_HEADER[] = 978 "# pack-refs with: peeled fully-peeled \n"; 979 980/* 981 * Parse one line from a packed-refs file. Write the SHA1 to sha1. 982 * Return a pointer to the refname within the line (null-terminated), 983 * or NULL if there was a problem. 984 */ 985static const char *parse_ref_line(struct strbuf *line, unsigned char *sha1) 986{ 987 const char *ref; 988 989 /* 990 * 42: the answer to everything. 991 * 992 * In this case, it happens to be the answer to 993 * 40 (length of sha1 hex representation) 994 * +1 (space in between hex and name) 995 * +1 (newline at the end of the line) 996 */ 997 if (line->len <= 42) 998 return NULL; 9991000 if (get_sha1_hex(line->buf, sha1) < 0)1001 return NULL;1002 if (!isspace(line->buf[40]))1003 return NULL;10041005 ref = line->buf + 41;1006 if (isspace(*ref))1007 return NULL;10081009 if (line->buf[line->len - 1] != '\n')1010 return NULL;1011 line->buf[--line->len] = 0;10121013 return ref;1014}10151016/*1017 * Read f, which is a packed-refs file, into dir.1018 *1019 * A comment line of the form "# pack-refs with: " may contain zero or1020 * more traits. We interpret the traits as follows:1021 *1022 * No traits:1023 *1024 * Probably no references are peeled. But if the file contains a1025 * peeled value for a reference, we will use it.1026 *1027 * peeled:1028 *1029 * References under "refs/tags/", if they *can* be peeled, *are*1030 * peeled in this file. References outside of "refs/tags/" are1031 * probably not peeled even if they could have been, but if we find1032 * a peeled value for such a reference we will use it.1033 *1034 * fully-peeled:1035 *1036 * All references in the file that can be peeled are peeled.1037 * Inversely (and this is more important), any references in the1038 * file for which no peeled value is recorded is not peelable. This1039 * trait should typically be written alongside "peeled" for1040 * compatibility with older clients, but we do not require it1041 * (i.e., "peeled" is a no-op if "fully-peeled" is set).1042 */1043static void read_packed_refs(FILE *f, struct ref_dir *dir)1044{1045 struct ref_entry *last = NULL;1046 struct strbuf line = STRBUF_INIT;1047 enum { PEELED_NONE, PEELED_TAGS, PEELED_FULLY } peeled = PEELED_NONE;10481049 while (strbuf_getwholeline(&line, f, '\n') != EOF) {1050 unsigned char sha1[20];1051 const char *refname;1052 const char *traits;10531054 if (skip_prefix(line.buf, "# pack-refs with:", &traits)) {1055 if (strstr(traits, " fully-peeled "))1056 peeled = PEELED_FULLY;1057 else if (strstr(traits, " peeled "))1058 peeled = PEELED_TAGS;1059 /* perhaps other traits later as well */1060 continue;1061 }10621063 refname = parse_ref_line(&line, sha1);1064 if (refname) {1065 int flag = REF_ISPACKED;10661067 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {1068 if (!refname_is_safe(refname))1069 die("packed refname is dangerous: %s", refname);1070 hashclr(sha1);1071 flag |= REF_BAD_NAME | REF_ISBROKEN;1072 }1073 last = create_ref_entry(refname, sha1, flag, 0);1074 if (peeled == PEELED_FULLY ||1075 (peeled == PEELED_TAGS && starts_with(refname, "refs/tags/")))1076 last->flag |= REF_KNOWS_PEELED;1077 add_ref(dir, last);1078 continue;1079 }1080 if (last &&1081 line.buf[0] == '^' &&1082 line.len == PEELED_LINE_LENGTH &&1083 line.buf[PEELED_LINE_LENGTH - 1] == '\n' &&1084 !get_sha1_hex(line.buf + 1, sha1)) {1085 hashcpy(last->u.value.peeled.hash, sha1);1086 /*1087 * Regardless of what the file header said,1088 * we definitely know the value of *this*1089 * reference:1090 */1091 last->flag |= REF_KNOWS_PEELED;1092 }1093 }10941095 strbuf_release(&line);1096}10971098/*1099 * Get the packed_ref_cache for the specified ref_cache, creating it1100 * if necessary.1101 */1102static struct packed_ref_cache *get_packed_ref_cache(struct ref_cache *refs)1103{1104 char *packed_refs_file;11051106 if (*refs->name)1107 packed_refs_file = git_pathdup_submodule(refs->name, "packed-refs");1108 else1109 packed_refs_file = git_pathdup("packed-refs");11101111 if (refs->packed &&1112 !stat_validity_check(&refs->packed->validity, packed_refs_file))1113 clear_packed_ref_cache(refs);11141115 if (!refs->packed) {1116 FILE *f;11171118 refs->packed = xcalloc(1, sizeof(*refs->packed));1119 acquire_packed_ref_cache(refs->packed);1120 refs->packed->root = create_dir_entry(refs, "", 0, 0);1121 f = fopen(packed_refs_file, "r");1122 if (f) {1123 stat_validity_update(&refs->packed->validity, fileno(f));1124 read_packed_refs(f, get_ref_dir(refs->packed->root));1125 fclose(f);1126 }1127 }1128 free(packed_refs_file);1129 return refs->packed;1130}11311132static struct ref_dir *get_packed_ref_dir(struct packed_ref_cache *packed_ref_cache)1133{1134 return get_ref_dir(packed_ref_cache->root);1135}11361137static struct ref_dir *get_packed_refs(struct ref_cache *refs)1138{1139 return get_packed_ref_dir(get_packed_ref_cache(refs));1140}11411142/*1143 * Add a reference to the in-memory packed reference cache. This may1144 * only be called while the packed-refs file is locked (see1145 * lock_packed_refs()). To actually write the packed-refs file, call1146 * commit_packed_refs().1147 */1148static void add_packed_ref(const char *refname, const unsigned char *sha1)1149{1150 struct packed_ref_cache *packed_ref_cache =1151 get_packed_ref_cache(&ref_cache);11521153 if (!packed_ref_cache->lock)1154 die("internal error: packed refs not locked");1155 add_ref(get_packed_ref_dir(packed_ref_cache),1156 create_ref_entry(refname, sha1, REF_ISPACKED, 1));1157}11581159/*1160 * Read the loose references from the namespace dirname into dir1161 * (without recursing). dirname must end with '/'. dir must be the1162 * directory entry corresponding to dirname.1163 */1164static void read_loose_refs(const char *dirname, struct ref_dir *dir)1165{1166 struct ref_cache *refs = dir->ref_cache;1167 DIR *d;1168 struct dirent *de;1169 int dirnamelen = strlen(dirname);1170 struct strbuf refname;1171 struct strbuf path = STRBUF_INIT;1172 size_t path_baselen;11731174 if (*refs->name)1175 strbuf_git_path_submodule(&path, refs->name, "%s", dirname);1176 else1177 strbuf_git_path(&path, "%s", dirname);1178 path_baselen = path.len;11791180 d = opendir(path.buf);1181 if (!d) {1182 strbuf_release(&path);1183 return;1184 }11851186 strbuf_init(&refname, dirnamelen + 257);1187 strbuf_add(&refname, dirname, dirnamelen);11881189 while ((de = readdir(d)) != NULL) {1190 unsigned char sha1[20];1191 struct stat st;1192 int flag;11931194 if (de->d_name[0] == '.')1195 continue;1196 if (ends_with(de->d_name, ".lock"))1197 continue;1198 strbuf_addstr(&refname, de->d_name);1199 strbuf_addstr(&path, de->d_name);1200 if (stat(path.buf, &st) < 0) {1201 ; /* silently ignore */1202 } else if (S_ISDIR(st.st_mode)) {1203 strbuf_addch(&refname, '/');1204 add_entry_to_dir(dir,1205 create_dir_entry(refs, refname.buf,1206 refname.len, 1));1207 } else {1208 int read_ok;12091210 if (*refs->name) {1211 hashclr(sha1);1212 flag = 0;1213 read_ok = !resolve_gitlink_ref(refs->name,1214 refname.buf, sha1);1215 } else {1216 read_ok = !read_ref_full(refname.buf,1217 RESOLVE_REF_READING,1218 sha1, &flag);1219 }12201221 if (!read_ok) {1222 hashclr(sha1);1223 flag |= REF_ISBROKEN;1224 } else if (is_null_sha1(sha1)) {1225 /*1226 * It is so astronomically unlikely1227 * that NULL_SHA1 is the SHA-1 of an1228 * actual object that we consider its1229 * appearance in a loose reference1230 * file to be repo corruption1231 * (probably due to a software bug).1232 */1233 flag |= REF_ISBROKEN;1234 }12351236 if (check_refname_format(refname.buf,1237 REFNAME_ALLOW_ONELEVEL)) {1238 if (!refname_is_safe(refname.buf))1239 die("loose refname is dangerous: %s", refname.buf);1240 hashclr(sha1);1241 flag |= REF_BAD_NAME | REF_ISBROKEN;1242 }1243 add_entry_to_dir(dir,1244 create_ref_entry(refname.buf, sha1, flag, 0));1245 }1246 strbuf_setlen(&refname, dirnamelen);1247 strbuf_setlen(&path, path_baselen);1248 }1249 strbuf_release(&refname);1250 strbuf_release(&path);1251 closedir(d);1252}12531254static struct ref_dir *get_loose_refs(struct ref_cache *refs)1255{1256 if (!refs->loose) {1257 /*1258 * Mark the top-level directory complete because we1259 * are about to read the only subdirectory that can1260 * hold references:1261 */1262 refs->loose = create_dir_entry(refs, "", 0, 0);1263 /*1264 * Create an incomplete entry for "refs/":1265 */1266 add_entry_to_dir(get_ref_dir(refs->loose),1267 create_dir_entry(refs, "refs/", 5, 1));1268 }1269 return get_ref_dir(refs->loose);1270}12711272#define MAXREFLEN (1024)12731274/*1275 * Called by resolve_gitlink_ref_recursive() after it failed to read1276 * from the loose refs in ref_cache refs. Find <refname> in the1277 * packed-refs file for the submodule.1278 */1279static int resolve_gitlink_packed_ref(struct ref_cache *refs,1280 const char *refname, unsigned char *sha1)1281{1282 struct ref_entry *ref;1283 struct ref_dir *dir = get_packed_refs(refs);12841285 ref = find_ref(dir, refname);1286 if (ref == NULL)1287 return -1;12881289 hashcpy(sha1, ref->u.value.oid.hash);1290 return 0;1291}12921293static int resolve_gitlink_ref_recursive(struct ref_cache *refs,1294 const char *refname, unsigned char *sha1,1295 int recursion)1296{1297 int fd, len;1298 char buffer[128], *p;1299 char *path;13001301 if (recursion > SYMREF_MAXDEPTH || strlen(refname) > MAXREFLEN)1302 return -1;1303 path = *refs->name1304 ? git_pathdup_submodule(refs->name, "%s", refname)1305 : git_pathdup("%s", refname);1306 fd = open(path, O_RDONLY);1307 free(path);1308 if (fd < 0)1309 return resolve_gitlink_packed_ref(refs, refname, sha1);13101311 len = read(fd, buffer, sizeof(buffer)-1);1312 close(fd);1313 if (len < 0)1314 return -1;1315 while (len && isspace(buffer[len-1]))1316 len--;1317 buffer[len] = 0;13181319 /* Was it a detached head or an old-fashioned symlink? */1320 if (!get_sha1_hex(buffer, sha1))1321 return 0;13221323 /* Symref? */1324 if (strncmp(buffer, "ref:", 4))1325 return -1;1326 p = buffer + 4;1327 while (isspace(*p))1328 p++;13291330 return resolve_gitlink_ref_recursive(refs, p, sha1, recursion+1);1331}13321333int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *sha1)1334{1335 int len = strlen(path), retval;1336 struct strbuf submodule = STRBUF_INIT;1337 struct ref_cache *refs;13381339 while (len && path[len-1] == '/')1340 len--;1341 if (!len)1342 return -1;13431344 strbuf_add(&submodule, path, len);1345 refs = lookup_ref_cache(submodule.buf);1346 if (!refs) {1347 if (!is_nonbare_repository_dir(&submodule)) {1348 strbuf_release(&submodule);1349 return -1;1350 }1351 refs = create_ref_cache(submodule.buf);1352 }1353 strbuf_release(&submodule);13541355 retval = resolve_gitlink_ref_recursive(refs, refname, sha1, 0);1356 return retval;1357}13581359/*1360 * Return the ref_entry for the given refname from the packed1361 * references. If it does not exist, return NULL.1362 */1363static struct ref_entry *get_packed_ref(const char *refname)1364{1365 return find_ref(get_packed_refs(&ref_cache), refname);1366}13671368/*1369 * A loose ref file doesn't exist; check for a packed ref.1370 */1371static int resolve_missing_loose_ref(const char *refname,1372 unsigned char *sha1,1373 unsigned int *flags)1374{1375 struct ref_entry *entry;13761377 /*1378 * The loose reference file does not exist; check for a packed1379 * reference.1380 */1381 entry = get_packed_ref(refname);1382 if (entry) {1383 hashcpy(sha1, entry->u.value.oid.hash);1384 *flags |= REF_ISPACKED;1385 return 0;1386 }1387 /* refname is not a packed reference. */1388 return -1;1389}13901391/*1392 * Read the specified reference from the filesystem or packed refs1393 * file, non-recursively. Set type to describe the reference, and:1394 *1395 * - If refname is the name of a normal reference, fill in sha11396 * (leaving referent unchanged).1397 *1398 * - If refname is the name of a symbolic reference, write the full1399 * name of the reference to which it refers (e.g.1400 * "refs/heads/master") to referent and set the REF_ISSYMREF bit in1401 * type (leaving sha1 unchanged). The caller is responsible for1402 * validating that referent is a valid reference name.1403 *1404 * WARNING: refname might be used as part of a filename, so it is1405 * important from a security standpoint that it be safe in the sense1406 * of refname_is_safe(). Moreover, for symrefs this function sets1407 * referent to whatever the repository says, which might not be a1408 * properly-formatted or even safe reference name. NEITHER INPUT NOR1409 * OUTPUT REFERENCE NAMES ARE VALIDATED WITHIN THIS FUNCTION.1410 *1411 * Return 0 on success. If the ref doesn't exist, set errno to ENOENT1412 * and return -1. If the ref exists but is neither a symbolic ref nor1413 * a sha1, it is broken; set REF_ISBROKEN in type, set errno to1414 * EINVAL, and return -1. If there is another error reading the ref,1415 * set errno appropriately and return -1.1416 *1417 * Backend-specific flags might be set in type as well, regardless of1418 * outcome.1419 *1420 * It is OK for refname to point into referent. If so:1421 *1422 * - if the function succeeds with REF_ISSYMREF, referent will be1423 * overwritten and the memory formerly pointed to by it might be1424 * changed or even freed.1425 *1426 * - in all other cases, referent will be untouched, and therefore1427 * refname will still be valid and unchanged.1428 */1429int read_raw_ref(const char *refname, unsigned char *sha1,1430 struct strbuf *referent, unsigned int *type)1431{1432 struct strbuf sb_contents = STRBUF_INIT;1433 struct strbuf sb_path = STRBUF_INIT;1434 const char *path;1435 const char *buf;1436 struct stat st;1437 int fd;1438 int ret = -1;1439 int save_errno;14401441 *type = 0;1442 strbuf_reset(&sb_path);1443 strbuf_git_path(&sb_path, "%s", refname);1444 path = sb_path.buf;14451446stat_ref:1447 /*1448 * We might have to loop back here to avoid a race1449 * condition: first we lstat() the file, then we try1450 * to read it as a link or as a file. But if somebody1451 * changes the type of the file (file <-> directory1452 * <-> symlink) between the lstat() and reading, then1453 * we don't want to report that as an error but rather1454 * try again starting with the lstat().1455 */14561457 if (lstat(path, &st) < 0) {1458 if (errno != ENOENT)1459 goto out;1460 if (resolve_missing_loose_ref(refname, sha1, type)) {1461 errno = ENOENT;1462 goto out;1463 }1464 ret = 0;1465 goto out;1466 }14671468 /* Follow "normalized" - ie "refs/.." symlinks by hand */1469 if (S_ISLNK(st.st_mode)) {1470 strbuf_reset(&sb_contents);1471 if (strbuf_readlink(&sb_contents, path, 0) < 0) {1472 if (errno == ENOENT || errno == EINVAL)1473 /* inconsistent with lstat; retry */1474 goto stat_ref;1475 else1476 goto out;1477 }1478 if (starts_with(sb_contents.buf, "refs/") &&1479 !check_refname_format(sb_contents.buf, 0)) {1480 strbuf_swap(&sb_contents, referent);1481 *type |= REF_ISSYMREF;1482 ret = 0;1483 goto out;1484 }1485 }14861487 /* Is it a directory? */1488 if (S_ISDIR(st.st_mode)) {1489 /*1490 * Even though there is a directory where the loose1491 * ref is supposed to be, there could still be a1492 * packed ref:1493 */1494 if (resolve_missing_loose_ref(refname, sha1, type)) {1495 errno = EISDIR;1496 goto out;1497 }1498 ret = 0;1499 goto out;1500 }15011502 /*1503 * Anything else, just open it and try to use it as1504 * a ref1505 */1506 fd = open(path, O_RDONLY);1507 if (fd < 0) {1508 if (errno == ENOENT)1509 /* inconsistent with lstat; retry */1510 goto stat_ref;1511 else1512 goto out;1513 }1514 strbuf_reset(&sb_contents);1515 if (strbuf_read(&sb_contents, fd, 256) < 0) {1516 int save_errno = errno;1517 close(fd);1518 errno = save_errno;1519 goto out;1520 }1521 close(fd);1522 strbuf_rtrim(&sb_contents);1523 buf = sb_contents.buf;1524 if (starts_with(buf, "ref:")) {1525 buf += 4;1526 while (isspace(*buf))1527 buf++;15281529 strbuf_reset(referent);1530 strbuf_addstr(referent, buf);1531 *type |= REF_ISSYMREF;1532 ret = 0;1533 goto out;1534 }15351536 /*1537 * Please note that FETCH_HEAD has additional1538 * data after the sha.1539 */1540 if (get_sha1_hex(buf, sha1) ||1541 (buf[40] != '\0' && !isspace(buf[40]))) {1542 *type |= REF_ISBROKEN;1543 errno = EINVAL;1544 goto out;1545 }15461547 ret = 0;15481549out:1550 save_errno = errno;1551 strbuf_release(&sb_path);1552 strbuf_release(&sb_contents);1553 errno = save_errno;1554 return ret;1555}15561557/*1558 * Peel the entry (if possible) and return its new peel_status. If1559 * repeel is true, re-peel the entry even if there is an old peeled1560 * value that is already stored in it.1561 *1562 * It is OK to call this function with a packed reference entry that1563 * might be stale and might even refer to an object that has since1564 * been garbage-collected. In such a case, if the entry has1565 * REF_KNOWS_PEELED then leave the status unchanged and return1566 * PEEL_PEELED or PEEL_NON_TAG; otherwise, return PEEL_INVALID.1567 */1568static enum peel_status peel_entry(struct ref_entry *entry, int repeel)1569{1570 enum peel_status status;15711572 if (entry->flag & REF_KNOWS_PEELED) {1573 if (repeel) {1574 entry->flag &= ~REF_KNOWS_PEELED;1575 oidclr(&entry->u.value.peeled);1576 } else {1577 return is_null_oid(&entry->u.value.peeled) ?1578 PEEL_NON_TAG : PEEL_PEELED;1579 }1580 }1581 if (entry->flag & REF_ISBROKEN)1582 return PEEL_BROKEN;1583 if (entry->flag & REF_ISSYMREF)1584 return PEEL_IS_SYMREF;15851586 status = peel_object(entry->u.value.oid.hash, entry->u.value.peeled.hash);1587 if (status == PEEL_PEELED || status == PEEL_NON_TAG)1588 entry->flag |= REF_KNOWS_PEELED;1589 return status;1590}15911592int peel_ref(const char *refname, unsigned char *sha1)1593{1594 int flag;1595 unsigned char base[20];15961597 if (current_ref && (current_ref->name == refname1598 || !strcmp(current_ref->name, refname))) {1599 if (peel_entry(current_ref, 0))1600 return -1;1601 hashcpy(sha1, current_ref->u.value.peeled.hash);1602 return 0;1603 }16041605 if (read_ref_full(refname, RESOLVE_REF_READING, base, &flag))1606 return -1;16071608 /*1609 * If the reference is packed, read its ref_entry from the1610 * cache in the hope that we already know its peeled value.1611 * We only try this optimization on packed references because1612 * (a) forcing the filling of the loose reference cache could1613 * be expensive and (b) loose references anyway usually do not1614 * have REF_KNOWS_PEELED.1615 */1616 if (flag & REF_ISPACKED) {1617 struct ref_entry *r = get_packed_ref(refname);1618 if (r) {1619 if (peel_entry(r, 0))1620 return -1;1621 hashcpy(sha1, r->u.value.peeled.hash);1622 return 0;1623 }1624 }16251626 return peel_object(base, sha1);1627}16281629/*1630 * Call fn for each reference in the specified ref_cache, omitting1631 * references not in the containing_dir of base. fn is called for all1632 * references, including broken ones. If fn ever returns a non-zero1633 * value, stop the iteration and return that value; otherwise, return1634 * 0.1635 */1636static int do_for_each_entry(struct ref_cache *refs, const char *base,1637 each_ref_entry_fn fn, void *cb_data)1638{1639 struct packed_ref_cache *packed_ref_cache;1640 struct ref_dir *loose_dir;1641 struct ref_dir *packed_dir;1642 int retval = 0;16431644 /*1645 * We must make sure that all loose refs are read before accessing the1646 * packed-refs file; this avoids a race condition in which loose refs1647 * are migrated to the packed-refs file by a simultaneous process, but1648 * our in-memory view is from before the migration. get_packed_ref_cache()1649 * takes care of making sure our view is up to date with what is on1650 * disk.1651 */1652 loose_dir = get_loose_refs(refs);1653 if (base && *base) {1654 loose_dir = find_containing_dir(loose_dir, base, 0);1655 }1656 if (loose_dir)1657 prime_ref_dir(loose_dir);16581659 packed_ref_cache = get_packed_ref_cache(refs);1660 acquire_packed_ref_cache(packed_ref_cache);1661 packed_dir = get_packed_ref_dir(packed_ref_cache);1662 if (base && *base) {1663 packed_dir = find_containing_dir(packed_dir, base, 0);1664 }16651666 if (packed_dir && loose_dir) {1667 sort_ref_dir(packed_dir);1668 sort_ref_dir(loose_dir);1669 retval = do_for_each_entry_in_dirs(1670 packed_dir, loose_dir, fn, cb_data);1671 } else if (packed_dir) {1672 sort_ref_dir(packed_dir);1673 retval = do_for_each_entry_in_dir(1674 packed_dir, 0, fn, cb_data);1675 } else if (loose_dir) {1676 sort_ref_dir(loose_dir);1677 retval = do_for_each_entry_in_dir(1678 loose_dir, 0, fn, cb_data);1679 }16801681 release_packed_ref_cache(packed_ref_cache);1682 return retval;1683}16841685/*1686 * Call fn for each reference in the specified ref_cache for which the1687 * refname begins with base. If trim is non-zero, then trim that many1688 * characters off the beginning of each refname before passing the1689 * refname to fn. flags can be DO_FOR_EACH_INCLUDE_BROKEN to include1690 * broken references in the iteration. If fn ever returns a non-zero1691 * value, stop the iteration and return that value; otherwise, return1692 * 0.1693 */1694int do_for_each_ref(const char *submodule, const char *base,1695 each_ref_fn fn, int trim, int flags, void *cb_data)1696{1697 struct ref_entry_cb data;1698 struct ref_cache *refs;16991700 refs = get_ref_cache(submodule);1701 data.base = base;1702 data.trim = trim;1703 data.flags = flags;1704 data.fn = fn;1705 data.cb_data = cb_data;17061707 if (ref_paranoia < 0)1708 ref_paranoia = git_env_bool("GIT_REF_PARANOIA", 0);1709 if (ref_paranoia)1710 data.flags |= DO_FOR_EACH_INCLUDE_BROKEN;17111712 return do_for_each_entry(refs, base, do_one_ref, &data);1713}17141715static void unlock_ref(struct ref_lock *lock)1716{1717 /* Do not free lock->lk -- atexit() still looks at them */1718 if (lock->lk)1719 rollback_lock_file(lock->lk);1720 free(lock->ref_name);1721 free(lock->orig_ref_name);1722 free(lock);1723}17241725/*1726 * Verify that the reference locked by lock has the value old_sha1.1727 * Fail if the reference doesn't exist and mustexist is set. Return 01728 * on success. On error, write an error message to err, set errno, and1729 * return a negative value.1730 */1731static int verify_lock(struct ref_lock *lock,1732 const unsigned char *old_sha1, int mustexist,1733 struct strbuf *err)1734{1735 assert(err);17361737 if (read_ref_full(lock->ref_name,1738 mustexist ? RESOLVE_REF_READING : 0,1739 lock->old_oid.hash, NULL)) {1740 if (old_sha1) {1741 int save_errno = errno;1742 strbuf_addf(err, "can't verify ref %s", lock->ref_name);1743 errno = save_errno;1744 return -1;1745 } else {1746 hashclr(lock->old_oid.hash);1747 return 0;1748 }1749 }1750 if (old_sha1 && hashcmp(lock->old_oid.hash, old_sha1)) {1751 strbuf_addf(err, "ref %s is at %s but expected %s",1752 lock->ref_name,1753 sha1_to_hex(lock->old_oid.hash),1754 sha1_to_hex(old_sha1));1755 errno = EBUSY;1756 return -1;1757 }1758 return 0;1759}17601761static int remove_empty_directories(struct strbuf *path)1762{1763 /*1764 * we want to create a file but there is a directory there;1765 * if that is an empty directory (or a directory that contains1766 * only empty directories), remove them.1767 */1768 return remove_dir_recursively(path, REMOVE_DIR_EMPTY_ONLY);1769}17701771/*1772 * Locks a ref returning the lock on success and NULL on failure.1773 * On failure errno is set to something meaningful.1774 */1775static struct ref_lock *lock_ref_sha1_basic(const char *refname,1776 const unsigned char *old_sha1,1777 const struct string_list *extras,1778 const struct string_list *skip,1779 unsigned int flags, int *type_p,1780 struct strbuf *err)1781{1782 struct strbuf ref_file = STRBUF_INIT;1783 struct strbuf orig_ref_file = STRBUF_INIT;1784 const char *orig_refname = refname;1785 struct ref_lock *lock;1786 int last_errno = 0;1787 int type;1788 int lflags = 0;1789 int mustexist = (old_sha1 && !is_null_sha1(old_sha1));1790 int resolve_flags = 0;1791 int attempts_remaining = 3;17921793 assert(err);17941795 lock = xcalloc(1, sizeof(struct ref_lock));17961797 if (mustexist)1798 resolve_flags |= RESOLVE_REF_READING;1799 if (flags & REF_DELETING)1800 resolve_flags |= RESOLVE_REF_ALLOW_BAD_NAME;1801 if (flags & REF_NODEREF) {1802 resolve_flags |= RESOLVE_REF_NO_RECURSE;1803 lflags |= LOCK_NO_DEREF;1804 }18051806 refname = resolve_ref_unsafe(refname, resolve_flags,1807 lock->old_oid.hash, &type);1808 if (!refname && errno == EISDIR) {1809 /*1810 * we are trying to lock foo but we used to1811 * have foo/bar which now does not exist;1812 * it is normal for the empty directory 'foo'1813 * to remain.1814 */1815 strbuf_git_path(&orig_ref_file, "%s", orig_refname);1816 if (remove_empty_directories(&orig_ref_file)) {1817 last_errno = errno;1818 if (!verify_refname_available_dir(orig_refname, extras, skip,1819 get_loose_refs(&ref_cache), err))1820 strbuf_addf(err, "there are still refs under '%s'",1821 orig_refname);1822 goto error_return;1823 }1824 refname = resolve_ref_unsafe(orig_refname, resolve_flags,1825 lock->old_oid.hash, &type);1826 }1827 if (type_p)1828 *type_p = type;1829 if (!refname) {1830 last_errno = errno;1831 if (last_errno != ENOTDIR ||1832 !verify_refname_available_dir(orig_refname, extras, skip,1833 get_loose_refs(&ref_cache), err))1834 strbuf_addf(err, "unable to resolve reference %s: %s",1835 orig_refname, strerror(last_errno));18361837 goto error_return;1838 }18391840 if (flags & REF_NODEREF)1841 refname = orig_refname;18421843 /*1844 * If the ref did not exist and we are creating it, make sure1845 * there is no existing packed ref whose name begins with our1846 * refname, nor a packed ref whose name is a proper prefix of1847 * our refname.1848 */1849 if (is_null_oid(&lock->old_oid) &&1850 verify_refname_available_dir(refname, extras, skip,1851 get_packed_refs(&ref_cache), err)) {1852 last_errno = ENOTDIR;1853 goto error_return;1854 }18551856 lock->lk = xcalloc(1, sizeof(struct lock_file));18571858 lock->ref_name = xstrdup(refname);1859 lock->orig_ref_name = xstrdup(orig_refname);1860 strbuf_git_path(&ref_file, "%s", refname);18611862 retry:1863 switch (safe_create_leading_directories_const(ref_file.buf)) {1864 case SCLD_OK:1865 break; /* success */1866 case SCLD_VANISHED:1867 if (--attempts_remaining > 0)1868 goto retry;1869 /* fall through */1870 default:1871 last_errno = errno;1872 strbuf_addf(err, "unable to create directory for %s",1873 ref_file.buf);1874 goto error_return;1875 }18761877 if (hold_lock_file_for_update(lock->lk, ref_file.buf, lflags) < 0) {1878 last_errno = errno;1879 if (errno == ENOENT && --attempts_remaining > 0)1880 /*1881 * Maybe somebody just deleted one of the1882 * directories leading to ref_file. Try1883 * again:1884 */1885 goto retry;1886 else {1887 unable_to_lock_message(ref_file.buf, errno, err);1888 goto error_return;1889 }1890 }1891 if (verify_lock(lock, old_sha1, mustexist, err)) {1892 last_errno = errno;1893 goto error_return;1894 }1895 goto out;18961897 error_return:1898 unlock_ref(lock);1899 lock = NULL;19001901 out:1902 strbuf_release(&ref_file);1903 strbuf_release(&orig_ref_file);1904 errno = last_errno;1905 return lock;1906}19071908/*1909 * Write an entry to the packed-refs file for the specified refname.1910 * If peeled is non-NULL, write it as the entry's peeled value.1911 */1912static void write_packed_entry(FILE *fh, char *refname, unsigned char *sha1,1913 unsigned char *peeled)1914{1915 fprintf_or_die(fh, "%s %s\n", sha1_to_hex(sha1), refname);1916 if (peeled)1917 fprintf_or_die(fh, "^%s\n", sha1_to_hex(peeled));1918}19191920/*1921 * An each_ref_entry_fn that writes the entry to a packed-refs file.1922 */1923static int write_packed_entry_fn(struct ref_entry *entry, void *cb_data)1924{1925 enum peel_status peel_status = peel_entry(entry, 0);19261927 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)1928 error("internal error: %s is not a valid packed reference!",1929 entry->name);1930 write_packed_entry(cb_data, entry->name, entry->u.value.oid.hash,1931 peel_status == PEEL_PEELED ?1932 entry->u.value.peeled.hash : NULL);1933 return 0;1934}19351936/*1937 * Lock the packed-refs file for writing. Flags is passed to1938 * hold_lock_file_for_update(). Return 0 on success. On errors, set1939 * errno appropriately and return a nonzero value.1940 */1941static int lock_packed_refs(int flags)1942{1943 static int timeout_configured = 0;1944 static int timeout_value = 1000;19451946 struct packed_ref_cache *packed_ref_cache;19471948 if (!timeout_configured) {1949 git_config_get_int("core.packedrefstimeout", &timeout_value);1950 timeout_configured = 1;1951 }19521953 if (hold_lock_file_for_update_timeout(1954 &packlock, git_path("packed-refs"),1955 flags, timeout_value) < 0)1956 return -1;1957 /*1958 * Get the current packed-refs while holding the lock. If the1959 * packed-refs file has been modified since we last read it,1960 * this will automatically invalidate the cache and re-read1961 * the packed-refs file.1962 */1963 packed_ref_cache = get_packed_ref_cache(&ref_cache);1964 packed_ref_cache->lock = &packlock;1965 /* Increment the reference count to prevent it from being freed: */1966 acquire_packed_ref_cache(packed_ref_cache);1967 return 0;1968}19691970/*1971 * Write the current version of the packed refs cache from memory to1972 * disk. The packed-refs file must already be locked for writing (see1973 * lock_packed_refs()). Return zero on success. On errors, set errno1974 * and return a nonzero value1975 */1976static int commit_packed_refs(void)1977{1978 struct packed_ref_cache *packed_ref_cache =1979 get_packed_ref_cache(&ref_cache);1980 int error = 0;1981 int save_errno = 0;1982 FILE *out;19831984 if (!packed_ref_cache->lock)1985 die("internal error: packed-refs not locked");19861987 out = fdopen_lock_file(packed_ref_cache->lock, "w");1988 if (!out)1989 die_errno("unable to fdopen packed-refs descriptor");19901991 fprintf_or_die(out, "%s", PACKED_REFS_HEADER);1992 do_for_each_entry_in_dir(get_packed_ref_dir(packed_ref_cache),1993 0, write_packed_entry_fn, out);19941995 if (commit_lock_file(packed_ref_cache->lock)) {1996 save_errno = errno;1997 error = -1;1998 }1999 packed_ref_cache->lock = NULL;2000 release_packed_ref_cache(packed_ref_cache);2001 errno = save_errno;2002 return error;2003}20042005/*2006 * Rollback the lockfile for the packed-refs file, and discard the2007 * in-memory packed reference cache. (The packed-refs file will be2008 * read anew if it is needed again after this function is called.)2009 */2010static void rollback_packed_refs(void)2011{2012 struct packed_ref_cache *packed_ref_cache =2013 get_packed_ref_cache(&ref_cache);20142015 if (!packed_ref_cache->lock)2016 die("internal error: packed-refs not locked");2017 rollback_lock_file(packed_ref_cache->lock);2018 packed_ref_cache->lock = NULL;2019 release_packed_ref_cache(packed_ref_cache);2020 clear_packed_ref_cache(&ref_cache);2021}20222023struct ref_to_prune {2024 struct ref_to_prune *next;2025 unsigned char sha1[20];2026 char name[FLEX_ARRAY];2027};20282029struct pack_refs_cb_data {2030 unsigned int flags;2031 struct ref_dir *packed_refs;2032 struct ref_to_prune *ref_to_prune;2033};20342035/*2036 * An each_ref_entry_fn that is run over loose references only. If2037 * the loose reference can be packed, add an entry in the packed ref2038 * cache. If the reference should be pruned, also add it to2039 * ref_to_prune in the pack_refs_cb_data.2040 */2041static int pack_if_possible_fn(struct ref_entry *entry, void *cb_data)2042{2043 struct pack_refs_cb_data *cb = cb_data;2044 enum peel_status peel_status;2045 struct ref_entry *packed_entry;2046 int is_tag_ref = starts_with(entry->name, "refs/tags/");20472048 /* Do not pack per-worktree refs: */2049 if (ref_type(entry->name) != REF_TYPE_NORMAL)2050 return 0;20512052 /* ALWAYS pack tags */2053 if (!(cb->flags & PACK_REFS_ALL) && !is_tag_ref)2054 return 0;20552056 /* Do not pack symbolic or broken refs: */2057 if ((entry->flag & REF_ISSYMREF) || !ref_resolves_to_object(entry))2058 return 0;20592060 /* Add a packed ref cache entry equivalent to the loose entry. */2061 peel_status = peel_entry(entry, 1);2062 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)2063 die("internal error peeling reference %s (%s)",2064 entry->name, oid_to_hex(&entry->u.value.oid));2065 packed_entry = find_ref(cb->packed_refs, entry->name);2066 if (packed_entry) {2067 /* Overwrite existing packed entry with info from loose entry */2068 packed_entry->flag = REF_ISPACKED | REF_KNOWS_PEELED;2069 oidcpy(&packed_entry->u.value.oid, &entry->u.value.oid);2070 } else {2071 packed_entry = create_ref_entry(entry->name, entry->u.value.oid.hash,2072 REF_ISPACKED | REF_KNOWS_PEELED, 0);2073 add_ref(cb->packed_refs, packed_entry);2074 }2075 oidcpy(&packed_entry->u.value.peeled, &entry->u.value.peeled);20762077 /* Schedule the loose reference for pruning if requested. */2078 if ((cb->flags & PACK_REFS_PRUNE)) {2079 struct ref_to_prune *n;2080 FLEX_ALLOC_STR(n, name, entry->name);2081 hashcpy(n->sha1, entry->u.value.oid.hash);2082 n->next = cb->ref_to_prune;2083 cb->ref_to_prune = n;2084 }2085 return 0;2086}20872088/*2089 * Remove empty parents, but spare refs/ and immediate subdirs.2090 * Note: munges *name.2091 */2092static void try_remove_empty_parents(char *name)2093{2094 char *p, *q;2095 int i;2096 p = name;2097 for (i = 0; i < 2; i++) { /* refs/{heads,tags,...}/ */2098 while (*p && *p != '/')2099 p++;2100 /* tolerate duplicate slashes; see check_refname_format() */2101 while (*p == '/')2102 p++;2103 }2104 for (q = p; *q; q++)2105 ;2106 while (1) {2107 while (q > p && *q != '/')2108 q--;2109 while (q > p && *(q-1) == '/')2110 q--;2111 if (q == p)2112 break;2113 *q = '\0';2114 if (rmdir(git_path("%s", name)))2115 break;2116 }2117}21182119/* make sure nobody touched the ref, and unlink */2120static void prune_ref(struct ref_to_prune *r)2121{2122 struct ref_transaction *transaction;2123 struct strbuf err = STRBUF_INIT;21242125 if (check_refname_format(r->name, 0))2126 return;21272128 transaction = ref_transaction_begin(&err);2129 if (!transaction ||2130 ref_transaction_delete(transaction, r->name, r->sha1,2131 REF_ISPRUNING, NULL, &err) ||2132 ref_transaction_commit(transaction, &err)) {2133 ref_transaction_free(transaction);2134 error("%s", err.buf);2135 strbuf_release(&err);2136 return;2137 }2138 ref_transaction_free(transaction);2139 strbuf_release(&err);2140 try_remove_empty_parents(r->name);2141}21422143static void prune_refs(struct ref_to_prune *r)2144{2145 while (r) {2146 prune_ref(r);2147 r = r->next;2148 }2149}21502151int pack_refs(unsigned int flags)2152{2153 struct pack_refs_cb_data cbdata;21542155 memset(&cbdata, 0, sizeof(cbdata));2156 cbdata.flags = flags;21572158 lock_packed_refs(LOCK_DIE_ON_ERROR);2159 cbdata.packed_refs = get_packed_refs(&ref_cache);21602161 do_for_each_entry_in_dir(get_loose_refs(&ref_cache), 0,2162 pack_if_possible_fn, &cbdata);21632164 if (commit_packed_refs())2165 die_errno("unable to overwrite old ref-pack file");21662167 prune_refs(cbdata.ref_to_prune);2168 return 0;2169}21702171/*2172 * Rewrite the packed-refs file, omitting any refs listed in2173 * 'refnames'. On error, leave packed-refs unchanged, write an error2174 * message to 'err', and return a nonzero value.2175 *2176 * The refs in 'refnames' needn't be sorted. `err` must not be NULL.2177 */2178static int repack_without_refs(struct string_list *refnames, struct strbuf *err)2179{2180 struct ref_dir *packed;2181 struct string_list_item *refname;2182 int ret, needs_repacking = 0, removed = 0;21832184 assert(err);21852186 /* Look for a packed ref */2187 for_each_string_list_item(refname, refnames) {2188 if (get_packed_ref(refname->string)) {2189 needs_repacking = 1;2190 break;2191 }2192 }21932194 /* Avoid locking if we have nothing to do */2195 if (!needs_repacking)2196 return 0; /* no refname exists in packed refs */21972198 if (lock_packed_refs(0)) {2199 unable_to_lock_message(git_path("packed-refs"), errno, err);2200 return -1;2201 }2202 packed = get_packed_refs(&ref_cache);22032204 /* Remove refnames from the cache */2205 for_each_string_list_item(refname, refnames)2206 if (remove_entry(packed, refname->string) != -1)2207 removed = 1;2208 if (!removed) {2209 /*2210 * All packed entries disappeared while we were2211 * acquiring the lock.2212 */2213 rollback_packed_refs();2214 return 0;2215 }22162217 /* Write what remains */2218 ret = commit_packed_refs();2219 if (ret)2220 strbuf_addf(err, "unable to overwrite old ref-pack file: %s",2221 strerror(errno));2222 return ret;2223}22242225static int delete_ref_loose(struct ref_lock *lock, int flag, struct strbuf *err)2226{2227 assert(err);22282229 if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {2230 /*2231 * loose. The loose file name is the same as the2232 * lockfile name, minus ".lock":2233 */2234 char *loose_filename = get_locked_file_path(lock->lk);2235 int res = unlink_or_msg(loose_filename, err);2236 free(loose_filename);2237 if (res)2238 return 1;2239 }2240 return 0;2241}22422243int delete_refs(struct string_list *refnames)2244{2245 struct strbuf err = STRBUF_INIT;2246 int i, result = 0;22472248 if (!refnames->nr)2249 return 0;22502251 result = repack_without_refs(refnames, &err);2252 if (result) {2253 /*2254 * If we failed to rewrite the packed-refs file, then2255 * it is unsafe to try to remove loose refs, because2256 * doing so might expose an obsolete packed value for2257 * a reference that might even point at an object that2258 * has been garbage collected.2259 */2260 if (refnames->nr == 1)2261 error(_("could not delete reference %s: %s"),2262 refnames->items[0].string, err.buf);2263 else2264 error(_("could not delete references: %s"), err.buf);22652266 goto out;2267 }22682269 for (i = 0; i < refnames->nr; i++) {2270 const char *refname = refnames->items[i].string;22712272 if (delete_ref(refname, NULL, 0))2273 result |= error(_("could not remove reference %s"), refname);2274 }22752276out:2277 strbuf_release(&err);2278 return result;2279}22802281/*2282 * People using contrib's git-new-workdir have .git/logs/refs ->2283 * /some/other/path/.git/logs/refs, and that may live on another device.2284 *2285 * IOW, to avoid cross device rename errors, the temporary renamed log must2286 * live into logs/refs.2287 */2288#define TMP_RENAMED_LOG "logs/refs/.tmp-renamed-log"22892290static int rename_tmp_log(const char *newrefname)2291{2292 int attempts_remaining = 4;2293 struct strbuf path = STRBUF_INIT;2294 int ret = -1;22952296 retry:2297 strbuf_reset(&path);2298 strbuf_git_path(&path, "logs/%s", newrefname);2299 switch (safe_create_leading_directories_const(path.buf)) {2300 case SCLD_OK:2301 break; /* success */2302 case SCLD_VANISHED:2303 if (--attempts_remaining > 0)2304 goto retry;2305 /* fall through */2306 default:2307 error("unable to create directory for %s", newrefname);2308 goto out;2309 }23102311 if (rename(git_path(TMP_RENAMED_LOG), path.buf)) {2312 if ((errno==EISDIR || errno==ENOTDIR) && --attempts_remaining > 0) {2313 /*2314 * rename(a, b) when b is an existing2315 * directory ought to result in ISDIR, but2316 * Solaris 5.8 gives ENOTDIR. Sheesh.2317 */2318 if (remove_empty_directories(&path)) {2319 error("Directory not empty: logs/%s", newrefname);2320 goto out;2321 }2322 goto retry;2323 } else if (errno == ENOENT && --attempts_remaining > 0) {2324 /*2325 * Maybe another process just deleted one of2326 * the directories in the path to newrefname.2327 * Try again from the beginning.2328 */2329 goto retry;2330 } else {2331 error("unable to move logfile "TMP_RENAMED_LOG" to logs/%s: %s",2332 newrefname, strerror(errno));2333 goto out;2334 }2335 }2336 ret = 0;2337out:2338 strbuf_release(&path);2339 return ret;2340}23412342int verify_refname_available(const char *newname,2343 struct string_list *extras,2344 struct string_list *skip,2345 struct strbuf *err)2346{2347 struct ref_dir *packed_refs = get_packed_refs(&ref_cache);2348 struct ref_dir *loose_refs = get_loose_refs(&ref_cache);23492350 if (verify_refname_available_dir(newname, extras, skip,2351 packed_refs, err) ||2352 verify_refname_available_dir(newname, extras, skip,2353 loose_refs, err))2354 return -1;23552356 return 0;2357}23582359static int write_ref_to_lockfile(struct ref_lock *lock,2360 const unsigned char *sha1, struct strbuf *err);2361static int commit_ref_update(struct ref_lock *lock,2362 const unsigned char *sha1, const char *logmsg,2363 int flags, struct strbuf *err);23642365int rename_ref(const char *oldrefname, const char *newrefname, const char *logmsg)2366{2367 unsigned char sha1[20], orig_sha1[20];2368 int flag = 0, logmoved = 0;2369 struct ref_lock *lock;2370 struct stat loginfo;2371 int log = !lstat(git_path("logs/%s", oldrefname), &loginfo);2372 struct strbuf err = STRBUF_INIT;23732374 if (log && S_ISLNK(loginfo.st_mode))2375 return error("reflog for %s is a symlink", oldrefname);23762377 if (!resolve_ref_unsafe(oldrefname, RESOLVE_REF_READING, orig_sha1, &flag))2378 return error("refname %s not found", oldrefname);23792380 if (flag & REF_ISSYMREF)2381 return error("refname %s is a symbolic ref, renaming it is not supported",2382 oldrefname);2383 if (!rename_ref_available(oldrefname, newrefname))2384 return 1;23852386 if (log && rename(git_path("logs/%s", oldrefname), git_path(TMP_RENAMED_LOG)))2387 return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",2388 oldrefname, strerror(errno));23892390 if (delete_ref(oldrefname, orig_sha1, REF_NODEREF)) {2391 error("unable to delete old %s", oldrefname);2392 goto rollback;2393 }23942395 if (!read_ref_full(newrefname, RESOLVE_REF_READING, sha1, NULL) &&2396 delete_ref(newrefname, sha1, REF_NODEREF)) {2397 if (errno==EISDIR) {2398 struct strbuf path = STRBUF_INIT;2399 int result;24002401 strbuf_git_path(&path, "%s", newrefname);2402 result = remove_empty_directories(&path);2403 strbuf_release(&path);24042405 if (result) {2406 error("Directory not empty: %s", newrefname);2407 goto rollback;2408 }2409 } else {2410 error("unable to delete existing %s", newrefname);2411 goto rollback;2412 }2413 }24142415 if (log && rename_tmp_log(newrefname))2416 goto rollback;24172418 logmoved = log;24192420 lock = lock_ref_sha1_basic(newrefname, NULL, NULL, NULL, 0, NULL, &err);2421 if (!lock) {2422 error("unable to rename '%s' to '%s': %s", oldrefname, newrefname, err.buf);2423 strbuf_release(&err);2424 goto rollback;2425 }2426 hashcpy(lock->old_oid.hash, orig_sha1);24272428 if (write_ref_to_lockfile(lock, orig_sha1, &err) ||2429 commit_ref_update(lock, orig_sha1, logmsg, 0, &err)) {2430 error("unable to write current sha1 into %s: %s", newrefname, err.buf);2431 strbuf_release(&err);2432 goto rollback;2433 }24342435 return 0;24362437 rollback:2438 lock = lock_ref_sha1_basic(oldrefname, NULL, NULL, NULL, 0, NULL, &err);2439 if (!lock) {2440 error("unable to lock %s for rollback: %s", oldrefname, err.buf);2441 strbuf_release(&err);2442 goto rollbacklog;2443 }24442445 flag = log_all_ref_updates;2446 log_all_ref_updates = 0;2447 if (write_ref_to_lockfile(lock, orig_sha1, &err) ||2448 commit_ref_update(lock, orig_sha1, NULL, 0, &err)) {2449 error("unable to write current sha1 into %s: %s", oldrefname, err.buf);2450 strbuf_release(&err);2451 }2452 log_all_ref_updates = flag;24532454 rollbacklog:2455 if (logmoved && rename(git_path("logs/%s", newrefname), git_path("logs/%s", oldrefname)))2456 error("unable to restore logfile %s from %s: %s",2457 oldrefname, newrefname, strerror(errno));2458 if (!logmoved && log &&2459 rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", oldrefname)))2460 error("unable to restore logfile %s from "TMP_RENAMED_LOG": %s",2461 oldrefname, strerror(errno));24622463 return 1;2464}24652466static int close_ref(struct ref_lock *lock)2467{2468 if (close_lock_file(lock->lk))2469 return -1;2470 return 0;2471}24722473static int commit_ref(struct ref_lock *lock)2474{2475 char *path = get_locked_file_path(lock->lk);2476 struct stat st;24772478 if (!lstat(path, &st) && S_ISDIR(st.st_mode)) {2479 /*2480 * There is a directory at the path we want to rename2481 * the lockfile to. Hopefully it is empty; try to2482 * delete it.2483 */2484 size_t len = strlen(path);2485 struct strbuf sb_path = STRBUF_INIT;24862487 strbuf_attach(&sb_path, path, len, len);24882489 /*2490 * If this fails, commit_lock_file() will also fail2491 * and will report the problem.2492 */2493 remove_empty_directories(&sb_path);2494 strbuf_release(&sb_path);2495 } else {2496 free(path);2497 }24982499 if (commit_lock_file(lock->lk))2500 return -1;2501 return 0;2502}25032504/*2505 * Create a reflog for a ref. If force_create = 0, the reflog will2506 * only be created for certain refs (those for which2507 * should_autocreate_reflog returns non-zero. Otherwise, create it2508 * regardless of the ref name. Fill in *err and return -1 on failure.2509 */2510static int log_ref_setup(const char *refname, struct strbuf *logfile, struct strbuf *err, int force_create)2511{2512 int logfd, oflags = O_APPEND | O_WRONLY;25132514 strbuf_git_path(logfile, "logs/%s", refname);2515 if (force_create || should_autocreate_reflog(refname)) {2516 if (safe_create_leading_directories(logfile->buf) < 0) {2517 strbuf_addf(err, "unable to create directory for %s: "2518 "%s", logfile->buf, strerror(errno));2519 return -1;2520 }2521 oflags |= O_CREAT;2522 }25232524 logfd = open(logfile->buf, oflags, 0666);2525 if (logfd < 0) {2526 if (!(oflags & O_CREAT) && (errno == ENOENT || errno == EISDIR))2527 return 0;25282529 if (errno == EISDIR) {2530 if (remove_empty_directories(logfile)) {2531 strbuf_addf(err, "There are still logs under "2532 "'%s'", logfile->buf);2533 return -1;2534 }2535 logfd = open(logfile->buf, oflags, 0666);2536 }25372538 if (logfd < 0) {2539 strbuf_addf(err, "unable to append to %s: %s",2540 logfile->buf, strerror(errno));2541 return -1;2542 }2543 }25442545 adjust_shared_perm(logfile->buf);2546 close(logfd);2547 return 0;2548}254925502551int safe_create_reflog(const char *refname, int force_create, struct strbuf *err)2552{2553 int ret;2554 struct strbuf sb = STRBUF_INIT;25552556 ret = log_ref_setup(refname, &sb, err, force_create);2557 strbuf_release(&sb);2558 return ret;2559}25602561static int log_ref_write_fd(int fd, const unsigned char *old_sha1,2562 const unsigned char *new_sha1,2563 const char *committer, const char *msg)2564{2565 int msglen, written;2566 unsigned maxlen, len;2567 char *logrec;25682569 msglen = msg ? strlen(msg) : 0;2570 maxlen = strlen(committer) + msglen + 100;2571 logrec = xmalloc(maxlen);2572 len = xsnprintf(logrec, maxlen, "%s %s %s\n",2573 sha1_to_hex(old_sha1),2574 sha1_to_hex(new_sha1),2575 committer);2576 if (msglen)2577 len += copy_reflog_msg(logrec + len - 1, msg) - 1;25782579 written = len <= maxlen ? write_in_full(fd, logrec, len) : -1;2580 free(logrec);2581 if (written != len)2582 return -1;25832584 return 0;2585}25862587static int log_ref_write_1(const char *refname, const unsigned char *old_sha1,2588 const unsigned char *new_sha1, const char *msg,2589 struct strbuf *logfile, int flags,2590 struct strbuf *err)2591{2592 int logfd, result, oflags = O_APPEND | O_WRONLY;25932594 if (log_all_ref_updates < 0)2595 log_all_ref_updates = !is_bare_repository();25962597 result = log_ref_setup(refname, logfile, err, flags & REF_FORCE_CREATE_REFLOG);25982599 if (result)2600 return result;26012602 logfd = open(logfile->buf, oflags);2603 if (logfd < 0)2604 return 0;2605 result = log_ref_write_fd(logfd, old_sha1, new_sha1,2606 git_committer_info(0), msg);2607 if (result) {2608 strbuf_addf(err, "unable to append to %s: %s", logfile->buf,2609 strerror(errno));2610 close(logfd);2611 return -1;2612 }2613 if (close(logfd)) {2614 strbuf_addf(err, "unable to append to %s: %s", logfile->buf,2615 strerror(errno));2616 return -1;2617 }2618 return 0;2619}26202621static int log_ref_write(const char *refname, const unsigned char *old_sha1,2622 const unsigned char *new_sha1, const char *msg,2623 int flags, struct strbuf *err)2624{2625 return files_log_ref_write(refname, old_sha1, new_sha1, msg, flags,2626 err);2627}26282629int files_log_ref_write(const char *refname, const unsigned char *old_sha1,2630 const unsigned char *new_sha1, const char *msg,2631 int flags, struct strbuf *err)2632{2633 struct strbuf sb = STRBUF_INIT;2634 int ret = log_ref_write_1(refname, old_sha1, new_sha1, msg, &sb, flags,2635 err);2636 strbuf_release(&sb);2637 return ret;2638}26392640/*2641 * Write sha1 into the open lockfile, then close the lockfile. On2642 * errors, rollback the lockfile, fill in *err and2643 * return -1.2644 */2645static int write_ref_to_lockfile(struct ref_lock *lock,2646 const unsigned char *sha1, struct strbuf *err)2647{2648 static char term = '\n';2649 struct object *o;2650 int fd;26512652 o = parse_object(sha1);2653 if (!o) {2654 strbuf_addf(err,2655 "Trying to write ref %s with nonexistent object %s",2656 lock->ref_name, sha1_to_hex(sha1));2657 unlock_ref(lock);2658 return -1;2659 }2660 if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {2661 strbuf_addf(err,2662 "Trying to write non-commit object %s to branch %s",2663 sha1_to_hex(sha1), lock->ref_name);2664 unlock_ref(lock);2665 return -1;2666 }2667 fd = get_lock_file_fd(lock->lk);2668 if (write_in_full(fd, sha1_to_hex(sha1), 40) != 40 ||2669 write_in_full(fd, &term, 1) != 1 ||2670 close_ref(lock) < 0) {2671 strbuf_addf(err,2672 "Couldn't write %s", get_lock_file_path(lock->lk));2673 unlock_ref(lock);2674 return -1;2675 }2676 return 0;2677}26782679/*2680 * Commit a change to a loose reference that has already been written2681 * to the loose reference lockfile. Also update the reflogs if2682 * necessary, using the specified lockmsg (which can be NULL).2683 */2684static int commit_ref_update(struct ref_lock *lock,2685 const unsigned char *sha1, const char *logmsg,2686 int flags, struct strbuf *err)2687{2688 clear_loose_ref_cache(&ref_cache);2689 if (log_ref_write(lock->ref_name, lock->old_oid.hash, sha1, logmsg, flags, err) < 0 ||2690 (strcmp(lock->ref_name, lock->orig_ref_name) &&2691 log_ref_write(lock->orig_ref_name, lock->old_oid.hash, sha1, logmsg, flags, err) < 0)) {2692 char *old_msg = strbuf_detach(err, NULL);2693 strbuf_addf(err, "Cannot update the ref '%s': %s",2694 lock->ref_name, old_msg);2695 free(old_msg);2696 unlock_ref(lock);2697 return -1;2698 }2699 if (strcmp(lock->orig_ref_name, "HEAD") != 0) {2700 /*2701 * Special hack: If a branch is updated directly and HEAD2702 * points to it (may happen on the remote side of a push2703 * for example) then logically the HEAD reflog should be2704 * updated too.2705 * A generic solution implies reverse symref information,2706 * but finding all symrefs pointing to the given branch2707 * would be rather costly for this rare event (the direct2708 * update of a branch) to be worth it. So let's cheat and2709 * check with HEAD only which should cover 99% of all usage2710 * scenarios (even 100% of the default ones).2711 */2712 unsigned char head_sha1[20];2713 int head_flag;2714 const char *head_ref;2715 head_ref = resolve_ref_unsafe("HEAD", RESOLVE_REF_READING,2716 head_sha1, &head_flag);2717 if (head_ref && (head_flag & REF_ISSYMREF) &&2718 !strcmp(head_ref, lock->ref_name)) {2719 struct strbuf log_err = STRBUF_INIT;2720 if (log_ref_write("HEAD", lock->old_oid.hash, sha1,2721 logmsg, 0, &log_err)) {2722 error("%s", log_err.buf);2723 strbuf_release(&log_err);2724 }2725 }2726 }2727 if (commit_ref(lock)) {2728 strbuf_addf(err, "Couldn't set %s", lock->ref_name);2729 unlock_ref(lock);2730 return -1;2731 }27322733 unlock_ref(lock);2734 return 0;2735}27362737static int create_ref_symlink(struct ref_lock *lock, const char *target)2738{2739 int ret = -1;2740#ifndef NO_SYMLINK_HEAD2741 char *ref_path = get_locked_file_path(lock->lk);2742 unlink(ref_path);2743 ret = symlink(target, ref_path);2744 free(ref_path);27452746 if (ret)2747 fprintf(stderr, "no symlink - falling back to symbolic ref\n");2748#endif2749 return ret;2750}27512752static void update_symref_reflog(struct ref_lock *lock, const char *refname,2753 const char *target, const char *logmsg)2754{2755 struct strbuf err = STRBUF_INIT;2756 unsigned char new_sha1[20];2757 if (logmsg && !read_ref(target, new_sha1) &&2758 log_ref_write(refname, lock->old_oid.hash, new_sha1, logmsg, 0, &err)) {2759 error("%s", err.buf);2760 strbuf_release(&err);2761 }2762}27632764static int create_symref_locked(struct ref_lock *lock, const char *refname,2765 const char *target, const char *logmsg)2766{2767 if (prefer_symlink_refs && !create_ref_symlink(lock, target)) {2768 update_symref_reflog(lock, refname, target, logmsg);2769 return 0;2770 }27712772 if (!fdopen_lock_file(lock->lk, "w"))2773 return error("unable to fdopen %s: %s",2774 lock->lk->tempfile.filename.buf, strerror(errno));27752776 update_symref_reflog(lock, refname, target, logmsg);27772778 /* no error check; commit_ref will check ferror */2779 fprintf(lock->lk->tempfile.fp, "ref: %s\n", target);2780 if (commit_ref(lock) < 0)2781 return error("unable to write symref for %s: %s", refname,2782 strerror(errno));2783 return 0;2784}27852786int create_symref(const char *refname, const char *target, const char *logmsg)2787{2788 struct strbuf err = STRBUF_INIT;2789 struct ref_lock *lock;2790 int ret;27912792 lock = lock_ref_sha1_basic(refname, NULL, NULL, NULL, REF_NODEREF, NULL,2793 &err);2794 if (!lock) {2795 error("%s", err.buf);2796 strbuf_release(&err);2797 return -1;2798 }27992800 ret = create_symref_locked(lock, refname, target, logmsg);2801 unlock_ref(lock);2802 return ret;2803}28042805int set_worktree_head_symref(const char *gitdir, const char *target)2806{2807 static struct lock_file head_lock;2808 struct ref_lock *lock;2809 struct strbuf head_path = STRBUF_INIT;2810 const char *head_rel;2811 int ret;28122813 strbuf_addf(&head_path, "%s/HEAD", absolute_path(gitdir));2814 if (hold_lock_file_for_update(&head_lock, head_path.buf,2815 LOCK_NO_DEREF) < 0) {2816 struct strbuf err = STRBUF_INIT;2817 unable_to_lock_message(head_path.buf, errno, &err);2818 error("%s", err.buf);2819 strbuf_release(&err);2820 strbuf_release(&head_path);2821 return -1;2822 }28232824 /* head_rel will be "HEAD" for the main tree, "worktrees/wt/HEAD" for2825 linked trees */2826 head_rel = remove_leading_path(head_path.buf,2827 absolute_path(get_git_common_dir()));2828 /* to make use of create_symref_locked(), initialize ref_lock */2829 lock = xcalloc(1, sizeof(struct ref_lock));2830 lock->lk = &head_lock;2831 lock->ref_name = xstrdup(head_rel);2832 lock->orig_ref_name = xstrdup(head_rel);28332834 ret = create_symref_locked(lock, head_rel, target, NULL);28352836 unlock_ref(lock); /* will free lock */2837 strbuf_release(&head_path);2838 return ret;2839}28402841int reflog_exists(const char *refname)2842{2843 struct stat st;28442845 return !lstat(git_path("logs/%s", refname), &st) &&2846 S_ISREG(st.st_mode);2847}28482849int delete_reflog(const char *refname)2850{2851 return remove_path(git_path("logs/%s", refname));2852}28532854static int show_one_reflog_ent(struct strbuf *sb, each_reflog_ent_fn fn, void *cb_data)2855{2856 unsigned char osha1[20], nsha1[20];2857 char *email_end, *message;2858 unsigned long timestamp;2859 int tz;28602861 /* old SP new SP name <email> SP time TAB msg LF */2862 if (sb->len < 83 || sb->buf[sb->len - 1] != '\n' ||2863 get_sha1_hex(sb->buf, osha1) || sb->buf[40] != ' ' ||2864 get_sha1_hex(sb->buf + 41, nsha1) || sb->buf[81] != ' ' ||2865 !(email_end = strchr(sb->buf + 82, '>')) ||2866 email_end[1] != ' ' ||2867 !(timestamp = strtoul(email_end + 2, &message, 10)) ||2868 !message || message[0] != ' ' ||2869 (message[1] != '+' && message[1] != '-') ||2870 !isdigit(message[2]) || !isdigit(message[3]) ||2871 !isdigit(message[4]) || !isdigit(message[5]))2872 return 0; /* corrupt? */2873 email_end[1] = '\0';2874 tz = strtol(message + 1, NULL, 10);2875 if (message[6] != '\t')2876 message += 6;2877 else2878 message += 7;2879 return fn(osha1, nsha1, sb->buf + 82, timestamp, tz, message, cb_data);2880}28812882static char *find_beginning_of_line(char *bob, char *scan)2883{2884 while (bob < scan && *(--scan) != '\n')2885 ; /* keep scanning backwards */2886 /*2887 * Return either beginning of the buffer, or LF at the end of2888 * the previous line.2889 */2890 return scan;2891}28922893int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn, void *cb_data)2894{2895 struct strbuf sb = STRBUF_INIT;2896 FILE *logfp;2897 long pos;2898 int ret = 0, at_tail = 1;28992900 logfp = fopen(git_path("logs/%s", refname), "r");2901 if (!logfp)2902 return -1;29032904 /* Jump to the end */2905 if (fseek(logfp, 0, SEEK_END) < 0)2906 return error("cannot seek back reflog for %s: %s",2907 refname, strerror(errno));2908 pos = ftell(logfp);2909 while (!ret && 0 < pos) {2910 int cnt;2911 size_t nread;2912 char buf[BUFSIZ];2913 char *endp, *scanp;29142915 /* Fill next block from the end */2916 cnt = (sizeof(buf) < pos) ? sizeof(buf) : pos;2917 if (fseek(logfp, pos - cnt, SEEK_SET))2918 return error("cannot seek back reflog for %s: %s",2919 refname, strerror(errno));2920 nread = fread(buf, cnt, 1, logfp);2921 if (nread != 1)2922 return error("cannot read %d bytes from reflog for %s: %s",2923 cnt, refname, strerror(errno));2924 pos -= cnt;29252926 scanp = endp = buf + cnt;2927 if (at_tail && scanp[-1] == '\n')2928 /* Looking at the final LF at the end of the file */2929 scanp--;2930 at_tail = 0;29312932 while (buf < scanp) {2933 /*2934 * terminating LF of the previous line, or the beginning2935 * of the buffer.2936 */2937 char *bp;29382939 bp = find_beginning_of_line(buf, scanp);29402941 if (*bp == '\n') {2942 /*2943 * The newline is the end of the previous line,2944 * so we know we have complete line starting2945 * at (bp + 1). Prefix it onto any prior data2946 * we collected for the line and process it.2947 */2948 strbuf_splice(&sb, 0, 0, bp + 1, endp - (bp + 1));2949 scanp = bp;2950 endp = bp + 1;2951 ret = show_one_reflog_ent(&sb, fn, cb_data);2952 strbuf_reset(&sb);2953 if (ret)2954 break;2955 } else if (!pos) {2956 /*2957 * We are at the start of the buffer, and the2958 * start of the file; there is no previous2959 * line, and we have everything for this one.2960 * Process it, and we can end the loop.2961 */2962 strbuf_splice(&sb, 0, 0, buf, endp - buf);2963 ret = show_one_reflog_ent(&sb, fn, cb_data);2964 strbuf_reset(&sb);2965 break;2966 }29672968 if (bp == buf) {2969 /*2970 * We are at the start of the buffer, and there2971 * is more file to read backwards. Which means2972 * we are in the middle of a line. Note that we2973 * may get here even if *bp was a newline; that2974 * just means we are at the exact end of the2975 * previous line, rather than some spot in the2976 * middle.2977 *2978 * Save away what we have to be combined with2979 * the data from the next read.2980 */2981 strbuf_splice(&sb, 0, 0, buf, endp - buf);2982 break;2983 }2984 }29852986 }2987 if (!ret && sb.len)2988 die("BUG: reverse reflog parser had leftover data");29892990 fclose(logfp);2991 strbuf_release(&sb);2992 return ret;2993}29942995int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn, void *cb_data)2996{2997 FILE *logfp;2998 struct strbuf sb = STRBUF_INIT;2999 int ret = 0;30003001 logfp = fopen(git_path("logs/%s", refname), "r");3002 if (!logfp)3003 return -1;30043005 while (!ret && !strbuf_getwholeline(&sb, logfp, '\n'))3006 ret = show_one_reflog_ent(&sb, fn, cb_data);3007 fclose(logfp);3008 strbuf_release(&sb);3009 return ret;3010}3011/*3012 * Call fn for each reflog in the namespace indicated by name. name3013 * must be empty or end with '/'. Name will be used as a scratch3014 * space, but its contents will be restored before return.3015 */3016static int do_for_each_reflog(struct strbuf *name, each_ref_fn fn, void *cb_data)3017{3018 DIR *d = opendir(git_path("logs/%s", name->buf));3019 int retval = 0;3020 struct dirent *de;3021 int oldlen = name->len;30223023 if (!d)3024 return name->len ? errno : 0;30253026 while ((de = readdir(d)) != NULL) {3027 struct stat st;30283029 if (de->d_name[0] == '.')3030 continue;3031 if (ends_with(de->d_name, ".lock"))3032 continue;3033 strbuf_addstr(name, de->d_name);3034 if (stat(git_path("logs/%s", name->buf), &st) < 0) {3035 ; /* silently ignore */3036 } else {3037 if (S_ISDIR(st.st_mode)) {3038 strbuf_addch(name, '/');3039 retval = do_for_each_reflog(name, fn, cb_data);3040 } else {3041 struct object_id oid;30423043 if (read_ref_full(name->buf, 0, oid.hash, NULL))3044 retval = error("bad ref for %s", name->buf);3045 else3046 retval = fn(name->buf, &oid, 0, cb_data);3047 }3048 if (retval)3049 break;3050 }3051 strbuf_setlen(name, oldlen);3052 }3053 closedir(d);3054 return retval;3055}30563057int for_each_reflog(each_ref_fn fn, void *cb_data)3058{3059 int retval;3060 struct strbuf name;3061 strbuf_init(&name, PATH_MAX);3062 retval = do_for_each_reflog(&name, fn, cb_data);3063 strbuf_release(&name);3064 return retval;3065}30663067static int ref_update_reject_duplicates(struct string_list *refnames,3068 struct strbuf *err)3069{3070 int i, n = refnames->nr;30713072 assert(err);30733074 for (i = 1; i < n; i++)3075 if (!strcmp(refnames->items[i - 1].string, refnames->items[i].string)) {3076 strbuf_addf(err,3077 "Multiple updates for ref '%s' not allowed.",3078 refnames->items[i].string);3079 return 1;3080 }3081 return 0;3082}30833084int ref_transaction_commit(struct ref_transaction *transaction,3085 struct strbuf *err)3086{3087 int ret = 0, i;3088 struct string_list refs_to_delete = STRING_LIST_INIT_NODUP;3089 struct string_list_item *ref_to_delete;3090 struct string_list affected_refnames = STRING_LIST_INIT_NODUP;30913092 assert(err);30933094 if (transaction->state != REF_TRANSACTION_OPEN)3095 die("BUG: commit called for transaction that is not open");30963097 if (!transaction->nr) {3098 transaction->state = REF_TRANSACTION_CLOSED;3099 return 0;3100 }31013102 /* Fail if a refname appears more than once in the transaction: */3103 for (i = 0; i < transaction->nr; i++)3104 string_list_append(&affected_refnames,3105 transaction->updates[i]->refname);3106 string_list_sort(&affected_refnames);3107 if (ref_update_reject_duplicates(&affected_refnames, err)) {3108 ret = TRANSACTION_GENERIC_ERROR;3109 goto cleanup;3110 }31113112 /*3113 * Acquire all locks, verify old values if provided, check3114 * that new values are valid, and write new values to the3115 * lockfiles, ready to be activated. Only keep one lockfile3116 * open at a time to avoid running out of file descriptors.3117 */3118 for (i = 0; i < transaction->nr; i++) {3119 struct ref_update *update = transaction->updates[i];31203121 if ((update->flags & REF_HAVE_NEW) &&3122 is_null_sha1(update->new_sha1))3123 update->flags |= REF_DELETING;3124 update->lock = lock_ref_sha1_basic(3125 update->refname,3126 ((update->flags & REF_HAVE_OLD) ?3127 update->old_sha1 : NULL),3128 &affected_refnames, NULL,3129 update->flags,3130 &update->type,3131 err);3132 if (!update->lock) {3133 char *reason;31343135 ret = (errno == ENOTDIR)3136 ? TRANSACTION_NAME_CONFLICT3137 : TRANSACTION_GENERIC_ERROR;3138 reason = strbuf_detach(err, NULL);3139 strbuf_addf(err, "cannot lock ref '%s': %s",3140 update->refname, reason);3141 free(reason);3142 goto cleanup;3143 }3144 if ((update->flags & REF_HAVE_NEW) &&3145 !(update->flags & REF_DELETING)) {3146 int overwriting_symref = ((update->type & REF_ISSYMREF) &&3147 (update->flags & REF_NODEREF));31483149 if (!overwriting_symref &&3150 !hashcmp(update->lock->old_oid.hash, update->new_sha1)) {3151 /*3152 * The reference already has the desired3153 * value, so we don't need to write it.3154 */3155 } else if (write_ref_to_lockfile(update->lock,3156 update->new_sha1,3157 err)) {3158 char *write_err = strbuf_detach(err, NULL);31593160 /*3161 * The lock was freed upon failure of3162 * write_ref_to_lockfile():3163 */3164 update->lock = NULL;3165 strbuf_addf(err,3166 "cannot update the ref '%s': %s",3167 update->refname, write_err);3168 free(write_err);3169 ret = TRANSACTION_GENERIC_ERROR;3170 goto cleanup;3171 } else {3172 update->flags |= REF_NEEDS_COMMIT;3173 }3174 }3175 if (!(update->flags & REF_NEEDS_COMMIT)) {3176 /*3177 * We didn't have to write anything to the lockfile.3178 * Close it to free up the file descriptor:3179 */3180 if (close_ref(update->lock)) {3181 strbuf_addf(err, "Couldn't close %s.lock",3182 update->refname);3183 goto cleanup;3184 }3185 }3186 }31873188 /* Perform updates first so live commits remain referenced */3189 for (i = 0; i < transaction->nr; i++) {3190 struct ref_update *update = transaction->updates[i];31913192 if (update->flags & REF_NEEDS_COMMIT) {3193 if (commit_ref_update(update->lock,3194 update->new_sha1, update->msg,3195 update->flags, err)) {3196 /* freed by commit_ref_update(): */3197 update->lock = NULL;3198 ret = TRANSACTION_GENERIC_ERROR;3199 goto cleanup;3200 } else {3201 /* freed by commit_ref_update(): */3202 update->lock = NULL;3203 }3204 }3205 }32063207 /* Perform deletes now that updates are safely completed */3208 for (i = 0; i < transaction->nr; i++) {3209 struct ref_update *update = transaction->updates[i];32103211 if (update->flags & REF_DELETING) {3212 if (delete_ref_loose(update->lock, update->type, err)) {3213 ret = TRANSACTION_GENERIC_ERROR;3214 goto cleanup;3215 }32163217 if (!(update->flags & REF_ISPRUNING))3218 string_list_append(&refs_to_delete,3219 update->lock->ref_name);3220 }3221 }32223223 if (repack_without_refs(&refs_to_delete, err)) {3224 ret = TRANSACTION_GENERIC_ERROR;3225 goto cleanup;3226 }3227 for_each_string_list_item(ref_to_delete, &refs_to_delete)3228 unlink_or_warn(git_path("logs/%s", ref_to_delete->string));3229 clear_loose_ref_cache(&ref_cache);32303231cleanup:3232 transaction->state = REF_TRANSACTION_CLOSED;32333234 for (i = 0; i < transaction->nr; i++)3235 if (transaction->updates[i]->lock)3236 unlock_ref(transaction->updates[i]->lock);3237 string_list_clear(&refs_to_delete, 0);3238 string_list_clear(&affected_refnames, 0);3239 return ret;3240}32413242static int ref_present(const char *refname,3243 const struct object_id *oid, int flags, void *cb_data)3244{3245 struct string_list *affected_refnames = cb_data;32463247 return string_list_has_string(affected_refnames, refname);3248}32493250int initial_ref_transaction_commit(struct ref_transaction *transaction,3251 struct strbuf *err)3252{3253 int ret = 0, i;3254 struct string_list affected_refnames = STRING_LIST_INIT_NODUP;32553256 assert(err);32573258 if (transaction->state != REF_TRANSACTION_OPEN)3259 die("BUG: commit called for transaction that is not open");32603261 /* Fail if a refname appears more than once in the transaction: */3262 for (i = 0; i < transaction->nr; i++)3263 string_list_append(&affected_refnames,3264 transaction->updates[i]->refname);3265 string_list_sort(&affected_refnames);3266 if (ref_update_reject_duplicates(&affected_refnames, err)) {3267 ret = TRANSACTION_GENERIC_ERROR;3268 goto cleanup;3269 }32703271 /*3272 * It's really undefined to call this function in an active3273 * repository or when there are existing references: we are3274 * only locking and changing packed-refs, so (1) any3275 * simultaneous processes might try to change a reference at3276 * the same time we do, and (2) any existing loose versions of3277 * the references that we are setting would have precedence3278 * over our values. But some remote helpers create the remote3279 * "HEAD" and "master" branches before calling this function,3280 * so here we really only check that none of the references3281 * that we are creating already exists.3282 */3283 if (for_each_rawref(ref_present, &affected_refnames))3284 die("BUG: initial ref transaction called with existing refs");32853286 for (i = 0; i < transaction->nr; i++) {3287 struct ref_update *update = transaction->updates[i];32883289 if ((update->flags & REF_HAVE_OLD) &&3290 !is_null_sha1(update->old_sha1))3291 die("BUG: initial ref transaction with old_sha1 set");3292 if (verify_refname_available(update->refname,3293 &affected_refnames, NULL,3294 err)) {3295 ret = TRANSACTION_NAME_CONFLICT;3296 goto cleanup;3297 }3298 }32993300 if (lock_packed_refs(0)) {3301 strbuf_addf(err, "unable to lock packed-refs file: %s",3302 strerror(errno));3303 ret = TRANSACTION_GENERIC_ERROR;3304 goto cleanup;3305 }33063307 for (i = 0; i < transaction->nr; i++) {3308 struct ref_update *update = transaction->updates[i];33093310 if ((update->flags & REF_HAVE_NEW) &&3311 !is_null_sha1(update->new_sha1))3312 add_packed_ref(update->refname, update->new_sha1);3313 }33143315 if (commit_packed_refs()) {3316 strbuf_addf(err, "unable to commit packed-refs file: %s",3317 strerror(errno));3318 ret = TRANSACTION_GENERIC_ERROR;3319 goto cleanup;3320 }33213322cleanup:3323 transaction->state = REF_TRANSACTION_CLOSED;3324 string_list_clear(&affected_refnames, 0);3325 return ret;3326}33273328struct expire_reflog_cb {3329 unsigned int flags;3330 reflog_expiry_should_prune_fn *should_prune_fn;3331 void *policy_cb;3332 FILE *newlog;3333 unsigned char last_kept_sha1[20];3334};33353336static int expire_reflog_ent(unsigned char *osha1, unsigned char *nsha1,3337 const char *email, unsigned long timestamp, int tz,3338 const char *message, void *cb_data)3339{3340 struct expire_reflog_cb *cb = cb_data;3341 struct expire_reflog_policy_cb *policy_cb = cb->policy_cb;33423343 if (cb->flags & EXPIRE_REFLOGS_REWRITE)3344 osha1 = cb->last_kept_sha1;33453346 if ((*cb->should_prune_fn)(osha1, nsha1, email, timestamp, tz,3347 message, policy_cb)) {3348 if (!cb->newlog)3349 printf("would prune %s", message);3350 else if (cb->flags & EXPIRE_REFLOGS_VERBOSE)3351 printf("prune %s", message);3352 } else {3353 if (cb->newlog) {3354 fprintf(cb->newlog, "%s %s %s %lu %+05d\t%s",3355 sha1_to_hex(osha1), sha1_to_hex(nsha1),3356 email, timestamp, tz, message);3357 hashcpy(cb->last_kept_sha1, nsha1);3358 }3359 if (cb->flags & EXPIRE_REFLOGS_VERBOSE)3360 printf("keep %s", message);3361 }3362 return 0;3363}33643365int reflog_expire(const char *refname, const unsigned char *sha1,3366 unsigned int flags,3367 reflog_expiry_prepare_fn prepare_fn,3368 reflog_expiry_should_prune_fn should_prune_fn,3369 reflog_expiry_cleanup_fn cleanup_fn,3370 void *policy_cb_data)3371{3372 static struct lock_file reflog_lock;3373 struct expire_reflog_cb cb;3374 struct ref_lock *lock;3375 char *log_file;3376 int status = 0;3377 int type;3378 struct strbuf err = STRBUF_INIT;33793380 memset(&cb, 0, sizeof(cb));3381 cb.flags = flags;3382 cb.policy_cb = policy_cb_data;3383 cb.should_prune_fn = should_prune_fn;33843385 /*3386 * The reflog file is locked by holding the lock on the3387 * reference itself, plus we might need to update the3388 * reference if --updateref was specified:3389 */3390 lock = lock_ref_sha1_basic(refname, sha1, NULL, NULL, REF_NODEREF,3391 &type, &err);3392 if (!lock) {3393 error("cannot lock ref '%s': %s", refname, err.buf);3394 strbuf_release(&err);3395 return -1;3396 }3397 if (!reflog_exists(refname)) {3398 unlock_ref(lock);3399 return 0;3400 }34013402 log_file = git_pathdup("logs/%s", refname);3403 if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {3404 /*3405 * Even though holding $GIT_DIR/logs/$reflog.lock has3406 * no locking implications, we use the lock_file3407 * machinery here anyway because it does a lot of the3408 * work we need, including cleaning up if the program3409 * exits unexpectedly.3410 */3411 if (hold_lock_file_for_update(&reflog_lock, log_file, 0) < 0) {3412 struct strbuf err = STRBUF_INIT;3413 unable_to_lock_message(log_file, errno, &err);3414 error("%s", err.buf);3415 strbuf_release(&err);3416 goto failure;3417 }3418 cb.newlog = fdopen_lock_file(&reflog_lock, "w");3419 if (!cb.newlog) {3420 error("cannot fdopen %s (%s)",3421 get_lock_file_path(&reflog_lock), strerror(errno));3422 goto failure;3423 }3424 }34253426 (*prepare_fn)(refname, sha1, cb.policy_cb);3427 for_each_reflog_ent(refname, expire_reflog_ent, &cb);3428 (*cleanup_fn)(cb.policy_cb);34293430 if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {3431 /*3432 * It doesn't make sense to adjust a reference pointed3433 * to by a symbolic ref based on expiring entries in3434 * the symbolic reference's reflog. Nor can we update3435 * a reference if there are no remaining reflog3436 * entries.3437 */3438 int update = (flags & EXPIRE_REFLOGS_UPDATE_REF) &&3439 !(type & REF_ISSYMREF) &&3440 !is_null_sha1(cb.last_kept_sha1);34413442 if (close_lock_file(&reflog_lock)) {3443 status |= error("couldn't write %s: %s", log_file,3444 strerror(errno));3445 } else if (update &&3446 (write_in_full(get_lock_file_fd(lock->lk),3447 sha1_to_hex(cb.last_kept_sha1), 40) != 40 ||3448 write_str_in_full(get_lock_file_fd(lock->lk), "\n") != 1 ||3449 close_ref(lock) < 0)) {3450 status |= error("couldn't write %s",3451 get_lock_file_path(lock->lk));3452 rollback_lock_file(&reflog_lock);3453 } else if (commit_lock_file(&reflog_lock)) {3454 status |= error("unable to write reflog '%s' (%s)",3455 log_file, strerror(errno));3456 } else if (update && commit_ref(lock)) {3457 status |= error("couldn't set %s", lock->ref_name);3458 }3459 }3460 free(log_file);3461 unlock_ref(lock);3462 return status;34633464 failure:3465 rollback_lock_file(&reflog_lock);3466 free(log_file);3467 unlock_ref(lock);3468 return -1;3469}