60f4fa5e7a5f22e9d47acd9600d85d8e4f09ec85
[git/git.git] / refs / files-backend.c
1 #include "../cache.h"
2 #include "../refs.h"
3 #include "refs-internal.h"
4 #include "ref-cache.h"
5 #include "packed-backend.h"
6 #include "../iterator.h"
7 #include "../dir-iterator.h"
8 #include "../lockfile.h"
9 #include "../object.h"
10 #include "../dir.h"
11
12 struct ref_lock {
13 char *ref_name;
14 struct lock_file *lk;
15 struct object_id old_oid;
16 };
17
18 /*
19 * Future: need to be in "struct repository"
20 * when doing a full libification.
21 */
22 struct files_ref_store {
23 struct ref_store base;
24 unsigned int store_flags;
25
26 char *gitdir;
27 char *gitcommondir;
28
29 struct ref_cache *loose;
30
31 struct ref_store *packed_ref_store;
32 };
33
34 static void clear_loose_ref_cache(struct files_ref_store *refs)
35 {
36 if (refs->loose) {
37 free_ref_cache(refs->loose);
38 refs->loose = NULL;
39 }
40 }
41
42 /*
43 * Create a new submodule ref cache and add it to the internal
44 * set of caches.
45 */
46 static struct ref_store *files_ref_store_create(const char *gitdir,
47 unsigned int flags)
48 {
49 struct files_ref_store *refs = xcalloc(1, sizeof(*refs));
50 struct ref_store *ref_store = (struct ref_store *)refs;
51 struct strbuf sb = STRBUF_INIT;
52
53 base_ref_store_init(ref_store, &refs_be_files);
54 refs->store_flags = flags;
55
56 refs->gitdir = xstrdup(gitdir);
57 get_common_dir_noenv(&sb, gitdir);
58 refs->gitcommondir = strbuf_detach(&sb, NULL);
59 strbuf_addf(&sb, "%s/packed-refs", refs->gitcommondir);
60 refs->packed_ref_store = packed_ref_store_create(sb.buf, flags);
61 strbuf_release(&sb);
62
63 return ref_store;
64 }
65
66 /*
67 * Die if refs is not the main ref store. caller is used in any
68 * necessary error messages.
69 */
70 static void files_assert_main_repository(struct files_ref_store *refs,
71 const char *caller)
72 {
73 if (refs->store_flags & REF_STORE_MAIN)
74 return;
75
76 die("BUG: operation %s only allowed for main ref store", caller);
77 }
78
79 /*
80 * Downcast ref_store to files_ref_store. Die if ref_store is not a
81 * files_ref_store. required_flags is compared with ref_store's
82 * store_flags to ensure the ref_store has all required capabilities.
83 * "caller" is used in any necessary error messages.
84 */
85 static struct files_ref_store *files_downcast(struct ref_store *ref_store,
86 unsigned int required_flags,
87 const char *caller)
88 {
89 struct files_ref_store *refs;
90
91 if (ref_store->be != &refs_be_files)
92 die("BUG: ref_store is type \"%s\" not \"files\" in %s",
93 ref_store->be->name, caller);
94
95 refs = (struct files_ref_store *)ref_store;
96
97 if ((refs->store_flags & required_flags) != required_flags)
98 die("BUG: operation %s requires abilities 0x%x, but only have 0x%x",
99 caller, required_flags, refs->store_flags);
100
101 return refs;
102 }
103
104 static void files_reflog_path(struct files_ref_store *refs,
105 struct strbuf *sb,
106 const char *refname)
107 {
108 if (!refname) {
109 /*
110 * FIXME: of course this is wrong in multi worktree
111 * setting. To be fixed real soon.
112 */
113 strbuf_addf(sb, "%s/logs", refs->gitcommondir);
114 return;
115 }
116
117 switch (ref_type(refname)) {
118 case REF_TYPE_PER_WORKTREE:
119 case REF_TYPE_PSEUDOREF:
120 strbuf_addf(sb, "%s/logs/%s", refs->gitdir, refname);
121 break;
122 case REF_TYPE_NORMAL:
123 strbuf_addf(sb, "%s/logs/%s", refs->gitcommondir, refname);
124 break;
125 default:
126 die("BUG: unknown ref type %d of ref %s",
127 ref_type(refname), refname);
128 }
129 }
130
131 static void files_ref_path(struct files_ref_store *refs,
132 struct strbuf *sb,
133 const char *refname)
134 {
135 switch (ref_type(refname)) {
136 case REF_TYPE_PER_WORKTREE:
137 case REF_TYPE_PSEUDOREF:
138 strbuf_addf(sb, "%s/%s", refs->gitdir, refname);
139 break;
140 case REF_TYPE_NORMAL:
141 strbuf_addf(sb, "%s/%s", refs->gitcommondir, refname);
142 break;
143 default:
144 die("BUG: unknown ref type %d of ref %s",
145 ref_type(refname), refname);
146 }
147 }
148
149 /*
150 * Read the loose references from the namespace dirname into dir
151 * (without recursing). dirname must end with '/'. dir must be the
152 * directory entry corresponding to dirname.
153 */
154 static void loose_fill_ref_dir(struct ref_store *ref_store,
155 struct ref_dir *dir, const char *dirname)
156 {
157 struct files_ref_store *refs =
158 files_downcast(ref_store, REF_STORE_READ, "fill_ref_dir");
159 DIR *d;
160 struct dirent *de;
161 int dirnamelen = strlen(dirname);
162 struct strbuf refname;
163 struct strbuf path = STRBUF_INIT;
164 size_t path_baselen;
165
166 files_ref_path(refs, &path, dirname);
167 path_baselen = path.len;
168
169 d = opendir(path.buf);
170 if (!d) {
171 strbuf_release(&path);
172 return;
173 }
174
175 strbuf_init(&refname, dirnamelen + 257);
176 strbuf_add(&refname, dirname, dirnamelen);
177
178 while ((de = readdir(d)) != NULL) {
179 struct object_id oid;
180 struct stat st;
181 int flag;
182
183 if (de->d_name[0] == '.')
184 continue;
185 if (ends_with(de->d_name, ".lock"))
186 continue;
187 strbuf_addstr(&refname, de->d_name);
188 strbuf_addstr(&path, de->d_name);
189 if (stat(path.buf, &st) < 0) {
190 ; /* silently ignore */
191 } else if (S_ISDIR(st.st_mode)) {
192 strbuf_addch(&refname, '/');
193 add_entry_to_dir(dir,
194 create_dir_entry(dir->cache, refname.buf,
195 refname.len, 1));
196 } else {
197 if (!refs_resolve_ref_unsafe(&refs->base,
198 refname.buf,
199 RESOLVE_REF_READING,
200 oid.hash, &flag)) {
201 oidclr(&oid);
202 flag |= REF_ISBROKEN;
203 } else if (is_null_oid(&oid)) {
204 /*
205 * It is so astronomically unlikely
206 * that NULL_SHA1 is the SHA-1 of an
207 * actual object that we consider its
208 * appearance in a loose reference
209 * file to be repo corruption
210 * (probably due to a software bug).
211 */
212 flag |= REF_ISBROKEN;
213 }
214
215 if (check_refname_format(refname.buf,
216 REFNAME_ALLOW_ONELEVEL)) {
217 if (!refname_is_safe(refname.buf))
218 die("loose refname is dangerous: %s", refname.buf);
219 oidclr(&oid);
220 flag |= REF_BAD_NAME | REF_ISBROKEN;
221 }
222 add_entry_to_dir(dir,
223 create_ref_entry(refname.buf, &oid, flag));
224 }
225 strbuf_setlen(&refname, dirnamelen);
226 strbuf_setlen(&path, path_baselen);
227 }
228 strbuf_release(&refname);
229 strbuf_release(&path);
230 closedir(d);
231
232 /*
233 * Manually add refs/bisect, which, being per-worktree, might
234 * not appear in the directory listing for refs/ in the main
235 * repo.
236 */
237 if (!strcmp(dirname, "refs/")) {
238 int pos = search_ref_dir(dir, "refs/bisect/", 12);
239
240 if (pos < 0) {
241 struct ref_entry *child_entry = create_dir_entry(
242 dir->cache, "refs/bisect/", 12, 1);
243 add_entry_to_dir(dir, child_entry);
244 }
245 }
246 }
247
248 static struct ref_cache *get_loose_ref_cache(struct files_ref_store *refs)
249 {
250 if (!refs->loose) {
251 /*
252 * Mark the top-level directory complete because we
253 * are about to read the only subdirectory that can
254 * hold references:
255 */
256 refs->loose = create_ref_cache(&refs->base, loose_fill_ref_dir);
257
258 /* We're going to fill the top level ourselves: */
259 refs->loose->root->flag &= ~REF_INCOMPLETE;
260
261 /*
262 * Add an incomplete entry for "refs/" (to be filled
263 * lazily):
264 */
265 add_entry_to_dir(get_ref_dir(refs->loose->root),
266 create_dir_entry(refs->loose, "refs/", 5, 1));
267 }
268 return refs->loose;
269 }
270
271 static int files_read_raw_ref(struct ref_store *ref_store,
272 const char *refname, unsigned char *sha1,
273 struct strbuf *referent, unsigned int *type)
274 {
275 struct files_ref_store *refs =
276 files_downcast(ref_store, REF_STORE_READ, "read_raw_ref");
277 struct strbuf sb_contents = STRBUF_INIT;
278 struct strbuf sb_path = STRBUF_INIT;
279 const char *path;
280 const char *buf;
281 struct stat st;
282 int fd;
283 int ret = -1;
284 int save_errno;
285 int remaining_retries = 3;
286
287 *type = 0;
288 strbuf_reset(&sb_path);
289
290 files_ref_path(refs, &sb_path, refname);
291
292 path = sb_path.buf;
293
294 stat_ref:
295 /*
296 * We might have to loop back here to avoid a race
297 * condition: first we lstat() the file, then we try
298 * to read it as a link or as a file. But if somebody
299 * changes the type of the file (file <-> directory
300 * <-> symlink) between the lstat() and reading, then
301 * we don't want to report that as an error but rather
302 * try again starting with the lstat().
303 *
304 * We'll keep a count of the retries, though, just to avoid
305 * any confusing situation sending us into an infinite loop.
306 */
307
308 if (remaining_retries-- <= 0)
309 goto out;
310
311 if (lstat(path, &st) < 0) {
312 if (errno != ENOENT)
313 goto out;
314 if (refs_read_raw_ref(refs->packed_ref_store, refname,
315 sha1, referent, type)) {
316 errno = ENOENT;
317 goto out;
318 }
319 ret = 0;
320 goto out;
321 }
322
323 /* Follow "normalized" - ie "refs/.." symlinks by hand */
324 if (S_ISLNK(st.st_mode)) {
325 strbuf_reset(&sb_contents);
326 if (strbuf_readlink(&sb_contents, path, 0) < 0) {
327 if (errno == ENOENT || errno == EINVAL)
328 /* inconsistent with lstat; retry */
329 goto stat_ref;
330 else
331 goto out;
332 }
333 if (starts_with(sb_contents.buf, "refs/") &&
334 !check_refname_format(sb_contents.buf, 0)) {
335 strbuf_swap(&sb_contents, referent);
336 *type |= REF_ISSYMREF;
337 ret = 0;
338 goto out;
339 }
340 /*
341 * It doesn't look like a refname; fall through to just
342 * treating it like a non-symlink, and reading whatever it
343 * points to.
344 */
345 }
346
347 /* Is it a directory? */
348 if (S_ISDIR(st.st_mode)) {
349 /*
350 * Even though there is a directory where the loose
351 * ref is supposed to be, there could still be a
352 * packed ref:
353 */
354 if (refs_read_raw_ref(refs->packed_ref_store, refname,
355 sha1, referent, type)) {
356 errno = EISDIR;
357 goto out;
358 }
359 ret = 0;
360 goto out;
361 }
362
363 /*
364 * Anything else, just open it and try to use it as
365 * a ref
366 */
367 fd = open(path, O_RDONLY);
368 if (fd < 0) {
369 if (errno == ENOENT && !S_ISLNK(st.st_mode))
370 /* inconsistent with lstat; retry */
371 goto stat_ref;
372 else
373 goto out;
374 }
375 strbuf_reset(&sb_contents);
376 if (strbuf_read(&sb_contents, fd, 256) < 0) {
377 int save_errno = errno;
378 close(fd);
379 errno = save_errno;
380 goto out;
381 }
382 close(fd);
383 strbuf_rtrim(&sb_contents);
384 buf = sb_contents.buf;
385 if (starts_with(buf, "ref:")) {
386 buf += 4;
387 while (isspace(*buf))
388 buf++;
389
390 strbuf_reset(referent);
391 strbuf_addstr(referent, buf);
392 *type |= REF_ISSYMREF;
393 ret = 0;
394 goto out;
395 }
396
397 /*
398 * Please note that FETCH_HEAD has additional
399 * data after the sha.
400 */
401 if (get_sha1_hex(buf, sha1) ||
402 (buf[40] != '\0' && !isspace(buf[40]))) {
403 *type |= REF_ISBROKEN;
404 errno = EINVAL;
405 goto out;
406 }
407
408 ret = 0;
409
410 out:
411 save_errno = errno;
412 strbuf_release(&sb_path);
413 strbuf_release(&sb_contents);
414 errno = save_errno;
415 return ret;
416 }
417
418 static void unlock_ref(struct ref_lock *lock)
419 {
420 /* Do not free lock->lk -- atexit() still looks at them */
421 if (lock->lk)
422 rollback_lock_file(lock->lk);
423 free(lock->ref_name);
424 free(lock);
425 }
426
427 /*
428 * Lock refname, without following symrefs, and set *lock_p to point
429 * at a newly-allocated lock object. Fill in lock->old_oid, referent,
430 * and type similarly to read_raw_ref().
431 *
432 * The caller must verify that refname is a "safe" reference name (in
433 * the sense of refname_is_safe()) before calling this function.
434 *
435 * If the reference doesn't already exist, verify that refname doesn't
436 * have a D/F conflict with any existing references. extras and skip
437 * are passed to refs_verify_refname_available() for this check.
438 *
439 * If mustexist is not set and the reference is not found or is
440 * broken, lock the reference anyway but clear sha1.
441 *
442 * Return 0 on success. On failure, write an error message to err and
443 * return TRANSACTION_NAME_CONFLICT or TRANSACTION_GENERIC_ERROR.
444 *
445 * Implementation note: This function is basically
446 *
447 * lock reference
448 * read_raw_ref()
449 *
450 * but it includes a lot more code to
451 * - Deal with possible races with other processes
452 * - Avoid calling refs_verify_refname_available() when it can be
453 * avoided, namely if we were successfully able to read the ref
454 * - Generate informative error messages in the case of failure
455 */
456 static int lock_raw_ref(struct files_ref_store *refs,
457 const char *refname, int mustexist,
458 const struct string_list *extras,
459 const struct string_list *skip,
460 struct ref_lock **lock_p,
461 struct strbuf *referent,
462 unsigned int *type,
463 struct strbuf *err)
464 {
465 struct ref_lock *lock;
466 struct strbuf ref_file = STRBUF_INIT;
467 int attempts_remaining = 3;
468 int ret = TRANSACTION_GENERIC_ERROR;
469
470 assert(err);
471 files_assert_main_repository(refs, "lock_raw_ref");
472
473 *type = 0;
474
475 /* First lock the file so it can't change out from under us. */
476
477 *lock_p = lock = xcalloc(1, sizeof(*lock));
478
479 lock->ref_name = xstrdup(refname);
480 files_ref_path(refs, &ref_file, refname);
481
482 retry:
483 switch (safe_create_leading_directories(ref_file.buf)) {
484 case SCLD_OK:
485 break; /* success */
486 case SCLD_EXISTS:
487 /*
488 * Suppose refname is "refs/foo/bar". We just failed
489 * to create the containing directory, "refs/foo",
490 * because there was a non-directory in the way. This
491 * indicates a D/F conflict, probably because of
492 * another reference such as "refs/foo". There is no
493 * reason to expect this error to be transitory.
494 */
495 if (refs_verify_refname_available(&refs->base, refname,
496 extras, skip, err)) {
497 if (mustexist) {
498 /*
499 * To the user the relevant error is
500 * that the "mustexist" reference is
501 * missing:
502 */
503 strbuf_reset(err);
504 strbuf_addf(err, "unable to resolve reference '%s'",
505 refname);
506 } else {
507 /*
508 * The error message set by
509 * refs_verify_refname_available() is
510 * OK.
511 */
512 ret = TRANSACTION_NAME_CONFLICT;
513 }
514 } else {
515 /*
516 * The file that is in the way isn't a loose
517 * reference. Report it as a low-level
518 * failure.
519 */
520 strbuf_addf(err, "unable to create lock file %s.lock; "
521 "non-directory in the way",
522 ref_file.buf);
523 }
524 goto error_return;
525 case SCLD_VANISHED:
526 /* Maybe another process was tidying up. Try again. */
527 if (--attempts_remaining > 0)
528 goto retry;
529 /* fall through */
530 default:
531 strbuf_addf(err, "unable to create directory for %s",
532 ref_file.buf);
533 goto error_return;
534 }
535
536 if (!lock->lk)
537 lock->lk = xcalloc(1, sizeof(struct lock_file));
538
539 if (hold_lock_file_for_update(lock->lk, ref_file.buf, LOCK_NO_DEREF) < 0) {
540 if (errno == ENOENT && --attempts_remaining > 0) {
541 /*
542 * Maybe somebody just deleted one of the
543 * directories leading to ref_file. Try
544 * again:
545 */
546 goto retry;
547 } else {
548 unable_to_lock_message(ref_file.buf, errno, err);
549 goto error_return;
550 }
551 }
552
553 /*
554 * Now we hold the lock and can read the reference without
555 * fear that its value will change.
556 */
557
558 if (files_read_raw_ref(&refs->base, refname,
559 lock->old_oid.hash, referent, type)) {
560 if (errno == ENOENT) {
561 if (mustexist) {
562 /* Garden variety missing reference. */
563 strbuf_addf(err, "unable to resolve reference '%s'",
564 refname);
565 goto error_return;
566 } else {
567 /*
568 * Reference is missing, but that's OK. We
569 * know that there is not a conflict with
570 * another loose reference because
571 * (supposing that we are trying to lock
572 * reference "refs/foo/bar"):
573 *
574 * - We were successfully able to create
575 * the lockfile refs/foo/bar.lock, so we
576 * know there cannot be a loose reference
577 * named "refs/foo".
578 *
579 * - We got ENOENT and not EISDIR, so we
580 * know that there cannot be a loose
581 * reference named "refs/foo/bar/baz".
582 */
583 }
584 } else if (errno == EISDIR) {
585 /*
586 * There is a directory in the way. It might have
587 * contained references that have been deleted. If
588 * we don't require that the reference already
589 * exists, try to remove the directory so that it
590 * doesn't cause trouble when we want to rename the
591 * lockfile into place later.
592 */
593 if (mustexist) {
594 /* Garden variety missing reference. */
595 strbuf_addf(err, "unable to resolve reference '%s'",
596 refname);
597 goto error_return;
598 } else if (remove_dir_recursively(&ref_file,
599 REMOVE_DIR_EMPTY_ONLY)) {
600 if (refs_verify_refname_available(
601 &refs->base, refname,
602 extras, skip, err)) {
603 /*
604 * The error message set by
605 * verify_refname_available() is OK.
606 */
607 ret = TRANSACTION_NAME_CONFLICT;
608 goto error_return;
609 } else {
610 /*
611 * We can't delete the directory,
612 * but we also don't know of any
613 * references that it should
614 * contain.
615 */
616 strbuf_addf(err, "there is a non-empty directory '%s' "
617 "blocking reference '%s'",
618 ref_file.buf, refname);
619 goto error_return;
620 }
621 }
622 } else if (errno == EINVAL && (*type & REF_ISBROKEN)) {
623 strbuf_addf(err, "unable to resolve reference '%s': "
624 "reference broken", refname);
625 goto error_return;
626 } else {
627 strbuf_addf(err, "unable to resolve reference '%s': %s",
628 refname, strerror(errno));
629 goto error_return;
630 }
631
632 /*
633 * If the ref did not exist and we are creating it,
634 * make sure there is no existing ref that conflicts
635 * with refname:
636 */
637 if (refs_verify_refname_available(
638 &refs->base, refname,
639 extras, skip, err))
640 goto error_return;
641 }
642
643 ret = 0;
644 goto out;
645
646 error_return:
647 unlock_ref(lock);
648 *lock_p = NULL;
649
650 out:
651 strbuf_release(&ref_file);
652 return ret;
653 }
654
655 static int files_peel_ref(struct ref_store *ref_store,
656 const char *refname, unsigned char *sha1)
657 {
658 struct files_ref_store *refs =
659 files_downcast(ref_store, REF_STORE_READ | REF_STORE_ODB,
660 "peel_ref");
661 int flag;
662 unsigned char base[20];
663
664 if (current_ref_iter && current_ref_iter->refname == refname) {
665 struct object_id peeled;
666
667 if (ref_iterator_peel(current_ref_iter, &peeled))
668 return -1;
669 hashcpy(sha1, peeled.hash);
670 return 0;
671 }
672
673 if (refs_read_ref_full(ref_store, refname,
674 RESOLVE_REF_READING, base, &flag))
675 return -1;
676
677 /*
678 * If the reference is packed, read its ref_entry from the
679 * cache in the hope that we already know its peeled value.
680 * We only try this optimization on packed references because
681 * (a) forcing the filling of the loose reference cache could
682 * be expensive and (b) loose references anyway usually do not
683 * have REF_KNOWS_PEELED.
684 */
685 if (flag & REF_ISPACKED &&
686 !refs_peel_ref(refs->packed_ref_store, refname, sha1))
687 return 0;
688
689 return peel_object(base, sha1);
690 }
691
692 struct files_ref_iterator {
693 struct ref_iterator base;
694
695 struct ref_iterator *iter0;
696 unsigned int flags;
697 };
698
699 static int files_ref_iterator_advance(struct ref_iterator *ref_iterator)
700 {
701 struct files_ref_iterator *iter =
702 (struct files_ref_iterator *)ref_iterator;
703 int ok;
704
705 while ((ok = ref_iterator_advance(iter->iter0)) == ITER_OK) {
706 if (iter->flags & DO_FOR_EACH_PER_WORKTREE_ONLY &&
707 ref_type(iter->iter0->refname) != REF_TYPE_PER_WORKTREE)
708 continue;
709
710 if (!(iter->flags & DO_FOR_EACH_INCLUDE_BROKEN) &&
711 !ref_resolves_to_object(iter->iter0->refname,
712 iter->iter0->oid,
713 iter->iter0->flags))
714 continue;
715
716 iter->base.refname = iter->iter0->refname;
717 iter->base.oid = iter->iter0->oid;
718 iter->base.flags = iter->iter0->flags;
719 return ITER_OK;
720 }
721
722 iter->iter0 = NULL;
723 if (ref_iterator_abort(ref_iterator) != ITER_DONE)
724 ok = ITER_ERROR;
725
726 return ok;
727 }
728
729 static int files_ref_iterator_peel(struct ref_iterator *ref_iterator,
730 struct object_id *peeled)
731 {
732 struct files_ref_iterator *iter =
733 (struct files_ref_iterator *)ref_iterator;
734
735 return ref_iterator_peel(iter->iter0, peeled);
736 }
737
738 static int files_ref_iterator_abort(struct ref_iterator *ref_iterator)
739 {
740 struct files_ref_iterator *iter =
741 (struct files_ref_iterator *)ref_iterator;
742 int ok = ITER_DONE;
743
744 if (iter->iter0)
745 ok = ref_iterator_abort(iter->iter0);
746
747 base_ref_iterator_free(ref_iterator);
748 return ok;
749 }
750
751 static struct ref_iterator_vtable files_ref_iterator_vtable = {
752 files_ref_iterator_advance,
753 files_ref_iterator_peel,
754 files_ref_iterator_abort
755 };
756
757 static struct ref_iterator *files_ref_iterator_begin(
758 struct ref_store *ref_store,
759 const char *prefix, unsigned int flags)
760 {
761 struct files_ref_store *refs;
762 struct ref_iterator *loose_iter, *packed_iter;
763 struct files_ref_iterator *iter;
764 struct ref_iterator *ref_iterator;
765 unsigned int required_flags = REF_STORE_READ;
766
767 if (!(flags & DO_FOR_EACH_INCLUDE_BROKEN))
768 required_flags |= REF_STORE_ODB;
769
770 refs = files_downcast(ref_store, required_flags, "ref_iterator_begin");
771
772 iter = xcalloc(1, sizeof(*iter));
773 ref_iterator = &iter->base;
774 base_ref_iterator_init(ref_iterator, &files_ref_iterator_vtable);
775
776 /*
777 * We must make sure that all loose refs are read before
778 * accessing the packed-refs file; this avoids a race
779 * condition if loose refs are migrated to the packed-refs
780 * file by a simultaneous process, but our in-memory view is
781 * from before the migration. We ensure this as follows:
782 * First, we call start the loose refs iteration with its
783 * `prime_ref` argument set to true. This causes the loose
784 * references in the subtree to be pre-read into the cache.
785 * (If they've already been read, that's OK; we only need to
786 * guarantee that they're read before the packed refs, not
787 * *how much* before.) After that, we call
788 * packed_ref_iterator_begin(), which internally checks
789 * whether the packed-ref cache is up to date with what is on
790 * disk, and re-reads it if not.
791 */
792
793 loose_iter = cache_ref_iterator_begin(get_loose_ref_cache(refs),
794 prefix, 1);
795
796 /*
797 * The packed-refs file might contain broken references, for
798 * example an old version of a reference that points at an
799 * object that has since been garbage-collected. This is OK as
800 * long as there is a corresponding loose reference that
801 * overrides it, and we don't want to emit an error message in
802 * this case. So ask the packed_ref_store for all of its
803 * references, and (if needed) do our own check for broken
804 * ones in files_ref_iterator_advance(), after we have merged
805 * the packed and loose references.
806 */
807 packed_iter = refs_ref_iterator_begin(
808 refs->packed_ref_store, prefix, 0,
809 DO_FOR_EACH_INCLUDE_BROKEN);
810
811 iter->iter0 = overlay_ref_iterator_begin(loose_iter, packed_iter);
812 iter->flags = flags;
813
814 return ref_iterator;
815 }
816
817 /*
818 * Verify that the reference locked by lock has the value old_sha1.
819 * Fail if the reference doesn't exist and mustexist is set. Return 0
820 * on success. On error, write an error message to err, set errno, and
821 * return a negative value.
822 */
823 static int verify_lock(struct ref_store *ref_store, struct ref_lock *lock,
824 const unsigned char *old_sha1, int mustexist,
825 struct strbuf *err)
826 {
827 assert(err);
828
829 if (refs_read_ref_full(ref_store, lock->ref_name,
830 mustexist ? RESOLVE_REF_READING : 0,
831 lock->old_oid.hash, NULL)) {
832 if (old_sha1) {
833 int save_errno = errno;
834 strbuf_addf(err, "can't verify ref '%s'", lock->ref_name);
835 errno = save_errno;
836 return -1;
837 } else {
838 oidclr(&lock->old_oid);
839 return 0;
840 }
841 }
842 if (old_sha1 && hashcmp(lock->old_oid.hash, old_sha1)) {
843 strbuf_addf(err, "ref '%s' is at %s but expected %s",
844 lock->ref_name,
845 oid_to_hex(&lock->old_oid),
846 sha1_to_hex(old_sha1));
847 errno = EBUSY;
848 return -1;
849 }
850 return 0;
851 }
852
853 static int remove_empty_directories(struct strbuf *path)
854 {
855 /*
856 * we want to create a file but there is a directory there;
857 * if that is an empty directory (or a directory that contains
858 * only empty directories), remove them.
859 */
860 return remove_dir_recursively(path, REMOVE_DIR_EMPTY_ONLY);
861 }
862
863 static int create_reflock(const char *path, void *cb)
864 {
865 struct lock_file *lk = cb;
866
867 return hold_lock_file_for_update(lk, path, LOCK_NO_DEREF) < 0 ? -1 : 0;
868 }
869
870 /*
871 * Locks a ref returning the lock on success and NULL on failure.
872 * On failure errno is set to something meaningful.
873 */
874 static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs,
875 const char *refname,
876 const unsigned char *old_sha1,
877 const struct string_list *extras,
878 const struct string_list *skip,
879 unsigned int flags, int *type,
880 struct strbuf *err)
881 {
882 struct strbuf ref_file = STRBUF_INIT;
883 struct ref_lock *lock;
884 int last_errno = 0;
885 int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
886 int resolve_flags = RESOLVE_REF_NO_RECURSE;
887 int resolved;
888
889 files_assert_main_repository(refs, "lock_ref_sha1_basic");
890 assert(err);
891
892 lock = xcalloc(1, sizeof(struct ref_lock));
893
894 if (mustexist)
895 resolve_flags |= RESOLVE_REF_READING;
896 if (flags & REF_DELETING)
897 resolve_flags |= RESOLVE_REF_ALLOW_BAD_NAME;
898
899 files_ref_path(refs, &ref_file, refname);
900 resolved = !!refs_resolve_ref_unsafe(&refs->base,
901 refname, resolve_flags,
902 lock->old_oid.hash, type);
903 if (!resolved && errno == EISDIR) {
904 /*
905 * we are trying to lock foo but we used to
906 * have foo/bar which now does not exist;
907 * it is normal for the empty directory 'foo'
908 * to remain.
909 */
910 if (remove_empty_directories(&ref_file)) {
911 last_errno = errno;
912 if (!refs_verify_refname_available(
913 &refs->base,
914 refname, extras, skip, err))
915 strbuf_addf(err, "there are still refs under '%s'",
916 refname);
917 goto error_return;
918 }
919 resolved = !!refs_resolve_ref_unsafe(&refs->base,
920 refname, resolve_flags,
921 lock->old_oid.hash, type);
922 }
923 if (!resolved) {
924 last_errno = errno;
925 if (last_errno != ENOTDIR ||
926 !refs_verify_refname_available(&refs->base, refname,
927 extras, skip, err))
928 strbuf_addf(err, "unable to resolve reference '%s': %s",
929 refname, strerror(last_errno));
930
931 goto error_return;
932 }
933
934 /*
935 * If the ref did not exist and we are creating it, make sure
936 * there is no existing packed ref whose name begins with our
937 * refname, nor a packed ref whose name is a proper prefix of
938 * our refname.
939 */
940 if (is_null_oid(&lock->old_oid) &&
941 refs_verify_refname_available(&refs->base, refname,
942 extras, skip, err)) {
943 last_errno = ENOTDIR;
944 goto error_return;
945 }
946
947 lock->lk = xcalloc(1, sizeof(struct lock_file));
948
949 lock->ref_name = xstrdup(refname);
950
951 if (raceproof_create_file(ref_file.buf, create_reflock, lock->lk)) {
952 last_errno = errno;
953 unable_to_lock_message(ref_file.buf, errno, err);
954 goto error_return;
955 }
956
957 if (verify_lock(&refs->base, lock, old_sha1, mustexist, err)) {
958 last_errno = errno;
959 goto error_return;
960 }
961 goto out;
962
963 error_return:
964 unlock_ref(lock);
965 lock = NULL;
966
967 out:
968 strbuf_release(&ref_file);
969 errno = last_errno;
970 return lock;
971 }
972
973 struct ref_to_prune {
974 struct ref_to_prune *next;
975 unsigned char sha1[20];
976 char name[FLEX_ARRAY];
977 };
978
979 enum {
980 REMOVE_EMPTY_PARENTS_REF = 0x01,
981 REMOVE_EMPTY_PARENTS_REFLOG = 0x02
982 };
983
984 /*
985 * Remove empty parent directories associated with the specified
986 * reference and/or its reflog, but spare [logs/]refs/ and immediate
987 * subdirs. flags is a combination of REMOVE_EMPTY_PARENTS_REF and/or
988 * REMOVE_EMPTY_PARENTS_REFLOG.
989 */
990 static void try_remove_empty_parents(struct files_ref_store *refs,
991 const char *refname,
992 unsigned int flags)
993 {
994 struct strbuf buf = STRBUF_INIT;
995 struct strbuf sb = STRBUF_INIT;
996 char *p, *q;
997 int i;
998
999 strbuf_addstr(&buf, refname);
1000 p = buf.buf;
1001 for (i = 0; i < 2; i++) { /* refs/{heads,tags,...}/ */
1002 while (*p && *p != '/')
1003 p++;
1004 /* tolerate duplicate slashes; see check_refname_format() */
1005 while (*p == '/')
1006 p++;
1007 }
1008 q = buf.buf + buf.len;
1009 while (flags & (REMOVE_EMPTY_PARENTS_REF | REMOVE_EMPTY_PARENTS_REFLOG)) {
1010 while (q > p && *q != '/')
1011 q--;
1012 while (q > p && *(q-1) == '/')
1013 q--;
1014 if (q == p)
1015 break;
1016 strbuf_setlen(&buf, q - buf.buf);
1017
1018 strbuf_reset(&sb);
1019 files_ref_path(refs, &sb, buf.buf);
1020 if ((flags & REMOVE_EMPTY_PARENTS_REF) && rmdir(sb.buf))
1021 flags &= ~REMOVE_EMPTY_PARENTS_REF;
1022
1023 strbuf_reset(&sb);
1024 files_reflog_path(refs, &sb, buf.buf);
1025 if ((flags & REMOVE_EMPTY_PARENTS_REFLOG) && rmdir(sb.buf))
1026 flags &= ~REMOVE_EMPTY_PARENTS_REFLOG;
1027 }
1028 strbuf_release(&buf);
1029 strbuf_release(&sb);
1030 }
1031
1032 /* make sure nobody touched the ref, and unlink */
1033 static void prune_ref(struct files_ref_store *refs, struct ref_to_prune *r)
1034 {
1035 struct ref_transaction *transaction;
1036 struct strbuf err = STRBUF_INIT;
1037
1038 if (check_refname_format(r->name, 0))
1039 return;
1040
1041 transaction = ref_store_transaction_begin(&refs->base, &err);
1042 if (!transaction ||
1043 ref_transaction_delete(transaction, r->name, r->sha1,
1044 REF_ISPRUNING | REF_NODEREF, NULL, &err) ||
1045 ref_transaction_commit(transaction, &err)) {
1046 ref_transaction_free(transaction);
1047 error("%s", err.buf);
1048 strbuf_release(&err);
1049 return;
1050 }
1051 ref_transaction_free(transaction);
1052 strbuf_release(&err);
1053 }
1054
1055 static void prune_refs(struct files_ref_store *refs, struct ref_to_prune *r)
1056 {
1057 while (r) {
1058 prune_ref(refs, r);
1059 r = r->next;
1060 }
1061 }
1062
1063 /*
1064 * Return true if the specified reference should be packed.
1065 */
1066 static int should_pack_ref(const char *refname,
1067 const struct object_id *oid, unsigned int ref_flags,
1068 unsigned int pack_flags)
1069 {
1070 /* Do not pack per-worktree refs: */
1071 if (ref_type(refname) != REF_TYPE_NORMAL)
1072 return 0;
1073
1074 /* Do not pack non-tags unless PACK_REFS_ALL is set: */
1075 if (!(pack_flags & PACK_REFS_ALL) && !starts_with(refname, "refs/tags/"))
1076 return 0;
1077
1078 /* Do not pack symbolic refs: */
1079 if (ref_flags & REF_ISSYMREF)
1080 return 0;
1081
1082 /* Do not pack broken refs: */
1083 if (!ref_resolves_to_object(refname, oid, ref_flags))
1084 return 0;
1085
1086 return 1;
1087 }
1088
1089 static int files_pack_refs(struct ref_store *ref_store, unsigned int flags)
1090 {
1091 struct files_ref_store *refs =
1092 files_downcast(ref_store, REF_STORE_WRITE | REF_STORE_ODB,
1093 "pack_refs");
1094 struct ref_iterator *iter;
1095 int ok;
1096 struct ref_to_prune *refs_to_prune = NULL;
1097
1098 lock_packed_refs(refs->packed_ref_store, LOCK_DIE_ON_ERROR);
1099
1100 iter = cache_ref_iterator_begin(get_loose_ref_cache(refs), NULL, 0);
1101 while ((ok = ref_iterator_advance(iter)) == ITER_OK) {
1102 /*
1103 * If the loose reference can be packed, add an entry
1104 * in the packed ref cache. If the reference should be
1105 * pruned, also add it to refs_to_prune.
1106 */
1107 if (!should_pack_ref(iter->refname, iter->oid, iter->flags,
1108 flags))
1109 continue;
1110
1111 /*
1112 * Create an entry in the packed-refs cache equivalent
1113 * to the one from the loose ref cache, except that
1114 * we don't copy the peeled status, because we want it
1115 * to be re-peeled.
1116 */
1117 add_packed_ref(refs->packed_ref_store, iter->refname, iter->oid);
1118
1119 /* Schedule the loose reference for pruning if requested. */
1120 if ((flags & PACK_REFS_PRUNE)) {
1121 struct ref_to_prune *n;
1122 FLEX_ALLOC_STR(n, name, iter->refname);
1123 hashcpy(n->sha1, iter->oid->hash);
1124 n->next = refs_to_prune;
1125 refs_to_prune = n;
1126 }
1127 }
1128 if (ok != ITER_DONE)
1129 die("error while iterating over references");
1130
1131 if (commit_packed_refs(refs->packed_ref_store))
1132 die_errno("unable to overwrite old ref-pack file");
1133
1134 prune_refs(refs, refs_to_prune);
1135 return 0;
1136 }
1137
1138 static int files_delete_refs(struct ref_store *ref_store, const char *msg,
1139 struct string_list *refnames, unsigned int flags)
1140 {
1141 struct files_ref_store *refs =
1142 files_downcast(ref_store, REF_STORE_WRITE, "delete_refs");
1143 struct strbuf err = STRBUF_INIT;
1144 int i, result = 0;
1145
1146 if (!refnames->nr)
1147 return 0;
1148
1149 result = repack_without_refs(refs->packed_ref_store, refnames, &err);
1150 if (result) {
1151 /*
1152 * If we failed to rewrite the packed-refs file, then
1153 * it is unsafe to try to remove loose refs, because
1154 * doing so might expose an obsolete packed value for
1155 * a reference that might even point at an object that
1156 * has been garbage collected.
1157 */
1158 if (refnames->nr == 1)
1159 error(_("could not delete reference %s: %s"),
1160 refnames->items[0].string, err.buf);
1161 else
1162 error(_("could not delete references: %s"), err.buf);
1163
1164 goto out;
1165 }
1166
1167 for (i = 0; i < refnames->nr; i++) {
1168 const char *refname = refnames->items[i].string;
1169
1170 if (refs_delete_ref(&refs->base, msg, refname, NULL, flags))
1171 result |= error(_("could not remove reference %s"), refname);
1172 }
1173
1174 out:
1175 strbuf_release(&err);
1176 return result;
1177 }
1178
1179 /*
1180 * People using contrib's git-new-workdir have .git/logs/refs ->
1181 * /some/other/path/.git/logs/refs, and that may live on another device.
1182 *
1183 * IOW, to avoid cross device rename errors, the temporary renamed log must
1184 * live into logs/refs.
1185 */
1186 #define TMP_RENAMED_LOG "refs/.tmp-renamed-log"
1187
1188 struct rename_cb {
1189 const char *tmp_renamed_log;
1190 int true_errno;
1191 };
1192
1193 static int rename_tmp_log_callback(const char *path, void *cb_data)
1194 {
1195 struct rename_cb *cb = cb_data;
1196
1197 if (rename(cb->tmp_renamed_log, path)) {
1198 /*
1199 * rename(a, b) when b is an existing directory ought
1200 * to result in ISDIR, but Solaris 5.8 gives ENOTDIR.
1201 * Sheesh. Record the true errno for error reporting,
1202 * but report EISDIR to raceproof_create_file() so
1203 * that it knows to retry.
1204 */
1205 cb->true_errno = errno;
1206 if (errno == ENOTDIR)
1207 errno = EISDIR;
1208 return -1;
1209 } else {
1210 return 0;
1211 }
1212 }
1213
1214 static int rename_tmp_log(struct files_ref_store *refs, const char *newrefname)
1215 {
1216 struct strbuf path = STRBUF_INIT;
1217 struct strbuf tmp = STRBUF_INIT;
1218 struct rename_cb cb;
1219 int ret;
1220
1221 files_reflog_path(refs, &path, newrefname);
1222 files_reflog_path(refs, &tmp, TMP_RENAMED_LOG);
1223 cb.tmp_renamed_log = tmp.buf;
1224 ret = raceproof_create_file(path.buf, rename_tmp_log_callback, &cb);
1225 if (ret) {
1226 if (errno == EISDIR)
1227 error("directory not empty: %s", path.buf);
1228 else
1229 error("unable to move logfile %s to %s: %s",
1230 tmp.buf, path.buf,
1231 strerror(cb.true_errno));
1232 }
1233
1234 strbuf_release(&path);
1235 strbuf_release(&tmp);
1236 return ret;
1237 }
1238
1239 static int write_ref_to_lockfile(struct ref_lock *lock,
1240 const struct object_id *oid, struct strbuf *err);
1241 static int commit_ref_update(struct files_ref_store *refs,
1242 struct ref_lock *lock,
1243 const struct object_id *oid, const char *logmsg,
1244 struct strbuf *err);
1245
1246 static int files_rename_ref(struct ref_store *ref_store,
1247 const char *oldrefname, const char *newrefname,
1248 const char *logmsg)
1249 {
1250 struct files_ref_store *refs =
1251 files_downcast(ref_store, REF_STORE_WRITE, "rename_ref");
1252 struct object_id oid, orig_oid;
1253 int flag = 0, logmoved = 0;
1254 struct ref_lock *lock;
1255 struct stat loginfo;
1256 struct strbuf sb_oldref = STRBUF_INIT;
1257 struct strbuf sb_newref = STRBUF_INIT;
1258 struct strbuf tmp_renamed_log = STRBUF_INIT;
1259 int log, ret;
1260 struct strbuf err = STRBUF_INIT;
1261
1262 files_reflog_path(refs, &sb_oldref, oldrefname);
1263 files_reflog_path(refs, &sb_newref, newrefname);
1264 files_reflog_path(refs, &tmp_renamed_log, TMP_RENAMED_LOG);
1265
1266 log = !lstat(sb_oldref.buf, &loginfo);
1267 if (log && S_ISLNK(loginfo.st_mode)) {
1268 ret = error("reflog for %s is a symlink", oldrefname);
1269 goto out;
1270 }
1271
1272 if (!refs_resolve_ref_unsafe(&refs->base, oldrefname,
1273 RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
1274 orig_oid.hash, &flag)) {
1275 ret = error("refname %s not found", oldrefname);
1276 goto out;
1277 }
1278
1279 if (flag & REF_ISSYMREF) {
1280 ret = error("refname %s is a symbolic ref, renaming it is not supported",
1281 oldrefname);
1282 goto out;
1283 }
1284 if (!refs_rename_ref_available(&refs->base, oldrefname, newrefname)) {
1285 ret = 1;
1286 goto out;
1287 }
1288
1289 if (log && rename(sb_oldref.buf, tmp_renamed_log.buf)) {
1290 ret = error("unable to move logfile logs/%s to logs/"TMP_RENAMED_LOG": %s",
1291 oldrefname, strerror(errno));
1292 goto out;
1293 }
1294
1295 if (refs_delete_ref(&refs->base, logmsg, oldrefname,
1296 orig_oid.hash, REF_NODEREF)) {
1297 error("unable to delete old %s", oldrefname);
1298 goto rollback;
1299 }
1300
1301 /*
1302 * Since we are doing a shallow lookup, oid is not the
1303 * correct value to pass to delete_ref as old_oid. But that
1304 * doesn't matter, because an old_oid check wouldn't add to
1305 * the safety anyway; we want to delete the reference whatever
1306 * its current value.
1307 */
1308 if (!refs_read_ref_full(&refs->base, newrefname,
1309 RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
1310 oid.hash, NULL) &&
1311 refs_delete_ref(&refs->base, NULL, newrefname,
1312 NULL, REF_NODEREF)) {
1313 if (errno == EISDIR) {
1314 struct strbuf path = STRBUF_INIT;
1315 int result;
1316
1317 files_ref_path(refs, &path, newrefname);
1318 result = remove_empty_directories(&path);
1319 strbuf_release(&path);
1320
1321 if (result) {
1322 error("Directory not empty: %s", newrefname);
1323 goto rollback;
1324 }
1325 } else {
1326 error("unable to delete existing %s", newrefname);
1327 goto rollback;
1328 }
1329 }
1330
1331 if (log && rename_tmp_log(refs, newrefname))
1332 goto rollback;
1333
1334 logmoved = log;
1335
1336 lock = lock_ref_sha1_basic(refs, newrefname, NULL, NULL, NULL,
1337 REF_NODEREF, NULL, &err);
1338 if (!lock) {
1339 error("unable to rename '%s' to '%s': %s", oldrefname, newrefname, err.buf);
1340 strbuf_release(&err);
1341 goto rollback;
1342 }
1343 oidcpy(&lock->old_oid, &orig_oid);
1344
1345 if (write_ref_to_lockfile(lock, &orig_oid, &err) ||
1346 commit_ref_update(refs, lock, &orig_oid, logmsg, &err)) {
1347 error("unable to write current sha1 into %s: %s", newrefname, err.buf);
1348 strbuf_release(&err);
1349 goto rollback;
1350 }
1351
1352 ret = 0;
1353 goto out;
1354
1355 rollback:
1356 lock = lock_ref_sha1_basic(refs, oldrefname, NULL, NULL, NULL,
1357 REF_NODEREF, NULL, &err);
1358 if (!lock) {
1359 error("unable to lock %s for rollback: %s", oldrefname, err.buf);
1360 strbuf_release(&err);
1361 goto rollbacklog;
1362 }
1363
1364 flag = log_all_ref_updates;
1365 log_all_ref_updates = LOG_REFS_NONE;
1366 if (write_ref_to_lockfile(lock, &orig_oid, &err) ||
1367 commit_ref_update(refs, lock, &orig_oid, NULL, &err)) {
1368 error("unable to write current sha1 into %s: %s", oldrefname, err.buf);
1369 strbuf_release(&err);
1370 }
1371 log_all_ref_updates = flag;
1372
1373 rollbacklog:
1374 if (logmoved && rename(sb_newref.buf, sb_oldref.buf))
1375 error("unable to restore logfile %s from %s: %s",
1376 oldrefname, newrefname, strerror(errno));
1377 if (!logmoved && log &&
1378 rename(tmp_renamed_log.buf, sb_oldref.buf))
1379 error("unable to restore logfile %s from logs/"TMP_RENAMED_LOG": %s",
1380 oldrefname, strerror(errno));
1381 ret = 1;
1382 out:
1383 strbuf_release(&sb_newref);
1384 strbuf_release(&sb_oldref);
1385 strbuf_release(&tmp_renamed_log);
1386
1387 return ret;
1388 }
1389
1390 static int close_ref(struct ref_lock *lock)
1391 {
1392 if (close_lock_file(lock->lk))
1393 return -1;
1394 return 0;
1395 }
1396
1397 static int commit_ref(struct ref_lock *lock)
1398 {
1399 char *path = get_locked_file_path(lock->lk);
1400 struct stat st;
1401
1402 if (!lstat(path, &st) && S_ISDIR(st.st_mode)) {
1403 /*
1404 * There is a directory at the path we want to rename
1405 * the lockfile to. Hopefully it is empty; try to
1406 * delete it.
1407 */
1408 size_t len = strlen(path);
1409 struct strbuf sb_path = STRBUF_INIT;
1410
1411 strbuf_attach(&sb_path, path, len, len);
1412
1413 /*
1414 * If this fails, commit_lock_file() will also fail
1415 * and will report the problem.
1416 */
1417 remove_empty_directories(&sb_path);
1418 strbuf_release(&sb_path);
1419 } else {
1420 free(path);
1421 }
1422
1423 if (commit_lock_file(lock->lk))
1424 return -1;
1425 return 0;
1426 }
1427
1428 static int open_or_create_logfile(const char *path, void *cb)
1429 {
1430 int *fd = cb;
1431
1432 *fd = open(path, O_APPEND | O_WRONLY | O_CREAT, 0666);
1433 return (*fd < 0) ? -1 : 0;
1434 }
1435
1436 /*
1437 * Create a reflog for a ref. If force_create = 0, only create the
1438 * reflog for certain refs (those for which should_autocreate_reflog
1439 * returns non-zero). Otherwise, create it regardless of the reference
1440 * name. If the logfile already existed or was created, return 0 and
1441 * set *logfd to the file descriptor opened for appending to the file.
1442 * If no logfile exists and we decided not to create one, return 0 and
1443 * set *logfd to -1. On failure, fill in *err, set *logfd to -1, and
1444 * return -1.
1445 */
1446 static int log_ref_setup(struct files_ref_store *refs,
1447 const char *refname, int force_create,
1448 int *logfd, struct strbuf *err)
1449 {
1450 struct strbuf logfile_sb = STRBUF_INIT;
1451 char *logfile;
1452
1453 files_reflog_path(refs, &logfile_sb, refname);
1454 logfile = strbuf_detach(&logfile_sb, NULL);
1455
1456 if (force_create || should_autocreate_reflog(refname)) {
1457 if (raceproof_create_file(logfile, open_or_create_logfile, logfd)) {
1458 if (errno == ENOENT)
1459 strbuf_addf(err, "unable to create directory for '%s': "
1460 "%s", logfile, strerror(errno));
1461 else if (errno == EISDIR)
1462 strbuf_addf(err, "there are still logs under '%s'",
1463 logfile);
1464 else
1465 strbuf_addf(err, "unable to append to '%s': %s",
1466 logfile, strerror(errno));
1467
1468 goto error;
1469 }
1470 } else {
1471 *logfd = open(logfile, O_APPEND | O_WRONLY, 0666);
1472 if (*logfd < 0) {
1473 if (errno == ENOENT || errno == EISDIR) {
1474 /*
1475 * The logfile doesn't already exist,
1476 * but that is not an error; it only
1477 * means that we won't write log
1478 * entries to it.
1479 */
1480 ;
1481 } else {
1482 strbuf_addf(err, "unable to append to '%s': %s",
1483 logfile, strerror(errno));
1484 goto error;
1485 }
1486 }
1487 }
1488
1489 if (*logfd >= 0)
1490 adjust_shared_perm(logfile);
1491
1492 free(logfile);
1493 return 0;
1494
1495 error:
1496 free(logfile);
1497 return -1;
1498 }
1499
1500 static int files_create_reflog(struct ref_store *ref_store,
1501 const char *refname, int force_create,
1502 struct strbuf *err)
1503 {
1504 struct files_ref_store *refs =
1505 files_downcast(ref_store, REF_STORE_WRITE, "create_reflog");
1506 int fd;
1507
1508 if (log_ref_setup(refs, refname, force_create, &fd, err))
1509 return -1;
1510
1511 if (fd >= 0)
1512 close(fd);
1513
1514 return 0;
1515 }
1516
1517 static int log_ref_write_fd(int fd, const struct object_id *old_oid,
1518 const struct object_id *new_oid,
1519 const char *committer, const char *msg)
1520 {
1521 int msglen, written;
1522 unsigned maxlen, len;
1523 char *logrec;
1524
1525 msglen = msg ? strlen(msg) : 0;
1526 maxlen = strlen(committer) + msglen + 100;
1527 logrec = xmalloc(maxlen);
1528 len = xsnprintf(logrec, maxlen, "%s %s %s\n",
1529 oid_to_hex(old_oid),
1530 oid_to_hex(new_oid),
1531 committer);
1532 if (msglen)
1533 len += copy_reflog_msg(logrec + len - 1, msg) - 1;
1534
1535 written = len <= maxlen ? write_in_full(fd, logrec, len) : -1;
1536 free(logrec);
1537 if (written != len)
1538 return -1;
1539
1540 return 0;
1541 }
1542
1543 static int files_log_ref_write(struct files_ref_store *refs,
1544 const char *refname, const struct object_id *old_oid,
1545 const struct object_id *new_oid, const char *msg,
1546 int flags, struct strbuf *err)
1547 {
1548 int logfd, result;
1549
1550 if (log_all_ref_updates == LOG_REFS_UNSET)
1551 log_all_ref_updates = is_bare_repository() ? LOG_REFS_NONE : LOG_REFS_NORMAL;
1552
1553 result = log_ref_setup(refs, refname,
1554 flags & REF_FORCE_CREATE_REFLOG,
1555 &logfd, err);
1556
1557 if (result)
1558 return result;
1559
1560 if (logfd < 0)
1561 return 0;
1562 result = log_ref_write_fd(logfd, old_oid, new_oid,
1563 git_committer_info(0), msg);
1564 if (result) {
1565 struct strbuf sb = STRBUF_INIT;
1566 int save_errno = errno;
1567
1568 files_reflog_path(refs, &sb, refname);
1569 strbuf_addf(err, "unable to append to '%s': %s",
1570 sb.buf, strerror(save_errno));
1571 strbuf_release(&sb);
1572 close(logfd);
1573 return -1;
1574 }
1575 if (close(logfd)) {
1576 struct strbuf sb = STRBUF_INIT;
1577 int save_errno = errno;
1578
1579 files_reflog_path(refs, &sb, refname);
1580 strbuf_addf(err, "unable to append to '%s': %s",
1581 sb.buf, strerror(save_errno));
1582 strbuf_release(&sb);
1583 return -1;
1584 }
1585 return 0;
1586 }
1587
1588 /*
1589 * Write sha1 into the open lockfile, then close the lockfile. On
1590 * errors, rollback the lockfile, fill in *err and
1591 * return -1.
1592 */
1593 static int write_ref_to_lockfile(struct ref_lock *lock,
1594 const struct object_id *oid, struct strbuf *err)
1595 {
1596 static char term = '\n';
1597 struct object *o;
1598 int fd;
1599
1600 o = parse_object(oid);
1601 if (!o) {
1602 strbuf_addf(err,
1603 "trying to write ref '%s' with nonexistent object %s",
1604 lock->ref_name, oid_to_hex(oid));
1605 unlock_ref(lock);
1606 return -1;
1607 }
1608 if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
1609 strbuf_addf(err,
1610 "trying to write non-commit object %s to branch '%s'",
1611 oid_to_hex(oid), lock->ref_name);
1612 unlock_ref(lock);
1613 return -1;
1614 }
1615 fd = get_lock_file_fd(lock->lk);
1616 if (write_in_full(fd, oid_to_hex(oid), GIT_SHA1_HEXSZ) != GIT_SHA1_HEXSZ ||
1617 write_in_full(fd, &term, 1) != 1 ||
1618 close_ref(lock) < 0) {
1619 strbuf_addf(err,
1620 "couldn't write '%s'", get_lock_file_path(lock->lk));
1621 unlock_ref(lock);
1622 return -1;
1623 }
1624 return 0;
1625 }
1626
1627 /*
1628 * Commit a change to a loose reference that has already been written
1629 * to the loose reference lockfile. Also update the reflogs if
1630 * necessary, using the specified lockmsg (which can be NULL).
1631 */
1632 static int commit_ref_update(struct files_ref_store *refs,
1633 struct ref_lock *lock,
1634 const struct object_id *oid, const char *logmsg,
1635 struct strbuf *err)
1636 {
1637 files_assert_main_repository(refs, "commit_ref_update");
1638
1639 clear_loose_ref_cache(refs);
1640 if (files_log_ref_write(refs, lock->ref_name,
1641 &lock->old_oid, oid,
1642 logmsg, 0, err)) {
1643 char *old_msg = strbuf_detach(err, NULL);
1644 strbuf_addf(err, "cannot update the ref '%s': %s",
1645 lock->ref_name, old_msg);
1646 free(old_msg);
1647 unlock_ref(lock);
1648 return -1;
1649 }
1650
1651 if (strcmp(lock->ref_name, "HEAD") != 0) {
1652 /*
1653 * Special hack: If a branch is updated directly and HEAD
1654 * points to it (may happen on the remote side of a push
1655 * for example) then logically the HEAD reflog should be
1656 * updated too.
1657 * A generic solution implies reverse symref information,
1658 * but finding all symrefs pointing to the given branch
1659 * would be rather costly for this rare event (the direct
1660 * update of a branch) to be worth it. So let's cheat and
1661 * check with HEAD only which should cover 99% of all usage
1662 * scenarios (even 100% of the default ones).
1663 */
1664 struct object_id head_oid;
1665 int head_flag;
1666 const char *head_ref;
1667
1668 head_ref = refs_resolve_ref_unsafe(&refs->base, "HEAD",
1669 RESOLVE_REF_READING,
1670 head_oid.hash, &head_flag);
1671 if (head_ref && (head_flag & REF_ISSYMREF) &&
1672 !strcmp(head_ref, lock->ref_name)) {
1673 struct strbuf log_err = STRBUF_INIT;
1674 if (files_log_ref_write(refs, "HEAD",
1675 &lock->old_oid, oid,
1676 logmsg, 0, &log_err)) {
1677 error("%s", log_err.buf);
1678 strbuf_release(&log_err);
1679 }
1680 }
1681 }
1682
1683 if (commit_ref(lock)) {
1684 strbuf_addf(err, "couldn't set '%s'", lock->ref_name);
1685 unlock_ref(lock);
1686 return -1;
1687 }
1688
1689 unlock_ref(lock);
1690 return 0;
1691 }
1692
1693 static int create_ref_symlink(struct ref_lock *lock, const char *target)
1694 {
1695 int ret = -1;
1696 #ifndef NO_SYMLINK_HEAD
1697 char *ref_path = get_locked_file_path(lock->lk);
1698 unlink(ref_path);
1699 ret = symlink(target, ref_path);
1700 free(ref_path);
1701
1702 if (ret)
1703 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
1704 #endif
1705 return ret;
1706 }
1707
1708 static void update_symref_reflog(struct files_ref_store *refs,
1709 struct ref_lock *lock, const char *refname,
1710 const char *target, const char *logmsg)
1711 {
1712 struct strbuf err = STRBUF_INIT;
1713 struct object_id new_oid;
1714 if (logmsg &&
1715 !refs_read_ref_full(&refs->base, target,
1716 RESOLVE_REF_READING, new_oid.hash, NULL) &&
1717 files_log_ref_write(refs, refname, &lock->old_oid,
1718 &new_oid, logmsg, 0, &err)) {
1719 error("%s", err.buf);
1720 strbuf_release(&err);
1721 }
1722 }
1723
1724 static int create_symref_locked(struct files_ref_store *refs,
1725 struct ref_lock *lock, const char *refname,
1726 const char *target, const char *logmsg)
1727 {
1728 if (prefer_symlink_refs && !create_ref_symlink(lock, target)) {
1729 update_symref_reflog(refs, lock, refname, target, logmsg);
1730 return 0;
1731 }
1732
1733 if (!fdopen_lock_file(lock->lk, "w"))
1734 return error("unable to fdopen %s: %s",
1735 lock->lk->tempfile.filename.buf, strerror(errno));
1736
1737 update_symref_reflog(refs, lock, refname, target, logmsg);
1738
1739 /* no error check; commit_ref will check ferror */
1740 fprintf(lock->lk->tempfile.fp, "ref: %s\n", target);
1741 if (commit_ref(lock) < 0)
1742 return error("unable to write symref for %s: %s", refname,
1743 strerror(errno));
1744 return 0;
1745 }
1746
1747 static int files_create_symref(struct ref_store *ref_store,
1748 const char *refname, const char *target,
1749 const char *logmsg)
1750 {
1751 struct files_ref_store *refs =
1752 files_downcast(ref_store, REF_STORE_WRITE, "create_symref");
1753 struct strbuf err = STRBUF_INIT;
1754 struct ref_lock *lock;
1755 int ret;
1756
1757 lock = lock_ref_sha1_basic(refs, refname, NULL,
1758 NULL, NULL, REF_NODEREF, NULL,
1759 &err);
1760 if (!lock) {
1761 error("%s", err.buf);
1762 strbuf_release(&err);
1763 return -1;
1764 }
1765
1766 ret = create_symref_locked(refs, lock, refname, target, logmsg);
1767 unlock_ref(lock);
1768 return ret;
1769 }
1770
1771 static int files_reflog_exists(struct ref_store *ref_store,
1772 const char *refname)
1773 {
1774 struct files_ref_store *refs =
1775 files_downcast(ref_store, REF_STORE_READ, "reflog_exists");
1776 struct strbuf sb = STRBUF_INIT;
1777 struct stat st;
1778 int ret;
1779
1780 files_reflog_path(refs, &sb, refname);
1781 ret = !lstat(sb.buf, &st) && S_ISREG(st.st_mode);
1782 strbuf_release(&sb);
1783 return ret;
1784 }
1785
1786 static int files_delete_reflog(struct ref_store *ref_store,
1787 const char *refname)
1788 {
1789 struct files_ref_store *refs =
1790 files_downcast(ref_store, REF_STORE_WRITE, "delete_reflog");
1791 struct strbuf sb = STRBUF_INIT;
1792 int ret;
1793
1794 files_reflog_path(refs, &sb, refname);
1795 ret = remove_path(sb.buf);
1796 strbuf_release(&sb);
1797 return ret;
1798 }
1799
1800 static int show_one_reflog_ent(struct strbuf *sb, each_reflog_ent_fn fn, void *cb_data)
1801 {
1802 struct object_id ooid, noid;
1803 char *email_end, *message;
1804 timestamp_t timestamp;
1805 int tz;
1806 const char *p = sb->buf;
1807
1808 /* old SP new SP name <email> SP time TAB msg LF */
1809 if (!sb->len || sb->buf[sb->len - 1] != '\n' ||
1810 parse_oid_hex(p, &ooid, &p) || *p++ != ' ' ||
1811 parse_oid_hex(p, &noid, &p) || *p++ != ' ' ||
1812 !(email_end = strchr(p, '>')) ||
1813 email_end[1] != ' ' ||
1814 !(timestamp = parse_timestamp(email_end + 2, &message, 10)) ||
1815 !message || message[0] != ' ' ||
1816 (message[1] != '+' && message[1] != '-') ||
1817 !isdigit(message[2]) || !isdigit(message[3]) ||
1818 !isdigit(message[4]) || !isdigit(message[5]))
1819 return 0; /* corrupt? */
1820 email_end[1] = '\0';
1821 tz = strtol(message + 1, NULL, 10);
1822 if (message[6] != '\t')
1823 message += 6;
1824 else
1825 message += 7;
1826 return fn(&ooid, &noid, p, timestamp, tz, message, cb_data);
1827 }
1828
1829 static char *find_beginning_of_line(char *bob, char *scan)
1830 {
1831 while (bob < scan && *(--scan) != '\n')
1832 ; /* keep scanning backwards */
1833 /*
1834 * Return either beginning of the buffer, or LF at the end of
1835 * the previous line.
1836 */
1837 return scan;
1838 }
1839
1840 static int files_for_each_reflog_ent_reverse(struct ref_store *ref_store,
1841 const char *refname,
1842 each_reflog_ent_fn fn,
1843 void *cb_data)
1844 {
1845 struct files_ref_store *refs =
1846 files_downcast(ref_store, REF_STORE_READ,
1847 "for_each_reflog_ent_reverse");
1848 struct strbuf sb = STRBUF_INIT;
1849 FILE *logfp;
1850 long pos;
1851 int ret = 0, at_tail = 1;
1852
1853 files_reflog_path(refs, &sb, refname);
1854 logfp = fopen(sb.buf, "r");
1855 strbuf_release(&sb);
1856 if (!logfp)
1857 return -1;
1858
1859 /* Jump to the end */
1860 if (fseek(logfp, 0, SEEK_END) < 0)
1861 ret = error("cannot seek back reflog for %s: %s",
1862 refname, strerror(errno));
1863 pos = ftell(logfp);
1864 while (!ret && 0 < pos) {
1865 int cnt;
1866 size_t nread;
1867 char buf[BUFSIZ];
1868 char *endp, *scanp;
1869
1870 /* Fill next block from the end */
1871 cnt = (sizeof(buf) < pos) ? sizeof(buf) : pos;
1872 if (fseek(logfp, pos - cnt, SEEK_SET)) {
1873 ret = error("cannot seek back reflog for %s: %s",
1874 refname, strerror(errno));
1875 break;
1876 }
1877 nread = fread(buf, cnt, 1, logfp);
1878 if (nread != 1) {
1879 ret = error("cannot read %d bytes from reflog for %s: %s",
1880 cnt, refname, strerror(errno));
1881 break;
1882 }
1883 pos -= cnt;
1884
1885 scanp = endp = buf + cnt;
1886 if (at_tail && scanp[-1] == '\n')
1887 /* Looking at the final LF at the end of the file */
1888 scanp--;
1889 at_tail = 0;
1890
1891 while (buf < scanp) {
1892 /*
1893 * terminating LF of the previous line, or the beginning
1894 * of the buffer.
1895 */
1896 char *bp;
1897
1898 bp = find_beginning_of_line(buf, scanp);
1899
1900 if (*bp == '\n') {
1901 /*
1902 * The newline is the end of the previous line,
1903 * so we know we have complete line starting
1904 * at (bp + 1). Prefix it onto any prior data
1905 * we collected for the line and process it.
1906 */
1907 strbuf_splice(&sb, 0, 0, bp + 1, endp - (bp + 1));
1908 scanp = bp;
1909 endp = bp + 1;
1910 ret = show_one_reflog_ent(&sb, fn, cb_data);
1911 strbuf_reset(&sb);
1912 if (ret)
1913 break;
1914 } else if (!pos) {
1915 /*
1916 * We are at the start of the buffer, and the
1917 * start of the file; there is no previous
1918 * line, and we have everything for this one.
1919 * Process it, and we can end the loop.
1920 */
1921 strbuf_splice(&sb, 0, 0, buf, endp - buf);
1922 ret = show_one_reflog_ent(&sb, fn, cb_data);
1923 strbuf_reset(&sb);
1924 break;
1925 }
1926
1927 if (bp == buf) {
1928 /*
1929 * We are at the start of the buffer, and there
1930 * is more file to read backwards. Which means
1931 * we are in the middle of a line. Note that we
1932 * may get here even if *bp was a newline; that
1933 * just means we are at the exact end of the
1934 * previous line, rather than some spot in the
1935 * middle.
1936 *
1937 * Save away what we have to be combined with
1938 * the data from the next read.
1939 */
1940 strbuf_splice(&sb, 0, 0, buf, endp - buf);
1941 break;
1942 }
1943 }
1944
1945 }
1946 if (!ret && sb.len)
1947 die("BUG: reverse reflog parser had leftover data");
1948
1949 fclose(logfp);
1950 strbuf_release(&sb);
1951 return ret;
1952 }
1953
1954 static int files_for_each_reflog_ent(struct ref_store *ref_store,
1955 const char *refname,
1956 each_reflog_ent_fn fn, void *cb_data)
1957 {
1958 struct files_ref_store *refs =
1959 files_downcast(ref_store, REF_STORE_READ,
1960 "for_each_reflog_ent");
1961 FILE *logfp;
1962 struct strbuf sb = STRBUF_INIT;
1963 int ret = 0;
1964
1965 files_reflog_path(refs, &sb, refname);
1966 logfp = fopen(sb.buf, "r");
1967 strbuf_release(&sb);
1968 if (!logfp)
1969 return -1;
1970
1971 while (!ret && !strbuf_getwholeline(&sb, logfp, '\n'))
1972 ret = show_one_reflog_ent(&sb, fn, cb_data);
1973 fclose(logfp);
1974 strbuf_release(&sb);
1975 return ret;
1976 }
1977
1978 struct files_reflog_iterator {
1979 struct ref_iterator base;
1980
1981 struct ref_store *ref_store;
1982 struct dir_iterator *dir_iterator;
1983 struct object_id oid;
1984 };
1985
1986 static int files_reflog_iterator_advance(struct ref_iterator *ref_iterator)
1987 {
1988 struct files_reflog_iterator *iter =
1989 (struct files_reflog_iterator *)ref_iterator;
1990 struct dir_iterator *diter = iter->dir_iterator;
1991 int ok;
1992
1993 while ((ok = dir_iterator_advance(diter)) == ITER_OK) {
1994 int flags;
1995
1996 if (!S_ISREG(diter->st.st_mode))
1997 continue;
1998 if (diter->basename[0] == '.')
1999 continue;
2000 if (ends_with(diter->basename, ".lock"))
2001 continue;
2002
2003 if (refs_read_ref_full(iter->ref_store,
2004 diter->relative_path, 0,
2005 iter->oid.hash, &flags)) {
2006 error("bad ref for %s", diter->path.buf);
2007 continue;
2008 }
2009
2010 iter->base.refname = diter->relative_path;
2011 iter->base.oid = &iter->oid;
2012 iter->base.flags = flags;
2013 return ITER_OK;
2014 }
2015
2016 iter->dir_iterator = NULL;
2017 if (ref_iterator_abort(ref_iterator) == ITER_ERROR)
2018 ok = ITER_ERROR;
2019 return ok;
2020 }
2021
2022 static int files_reflog_iterator_peel(struct ref_iterator *ref_iterator,
2023 struct object_id *peeled)
2024 {
2025 die("BUG: ref_iterator_peel() called for reflog_iterator");
2026 }
2027
2028 static int files_reflog_iterator_abort(struct ref_iterator *ref_iterator)
2029 {
2030 struct files_reflog_iterator *iter =
2031 (struct files_reflog_iterator *)ref_iterator;
2032 int ok = ITER_DONE;
2033
2034 if (iter->dir_iterator)
2035 ok = dir_iterator_abort(iter->dir_iterator);
2036
2037 base_ref_iterator_free(ref_iterator);
2038 return ok;
2039 }
2040
2041 static struct ref_iterator_vtable files_reflog_iterator_vtable = {
2042 files_reflog_iterator_advance,
2043 files_reflog_iterator_peel,
2044 files_reflog_iterator_abort
2045 };
2046
2047 static struct ref_iterator *files_reflog_iterator_begin(struct ref_store *ref_store)
2048 {
2049 struct files_ref_store *refs =
2050 files_downcast(ref_store, REF_STORE_READ,
2051 "reflog_iterator_begin");
2052 struct files_reflog_iterator *iter = xcalloc(1, sizeof(*iter));
2053 struct ref_iterator *ref_iterator = &iter->base;
2054 struct strbuf sb = STRBUF_INIT;
2055
2056 base_ref_iterator_init(ref_iterator, &files_reflog_iterator_vtable);
2057 files_reflog_path(refs, &sb, NULL);
2058 iter->dir_iterator = dir_iterator_begin(sb.buf);
2059 iter->ref_store = ref_store;
2060 strbuf_release(&sb);
2061 return ref_iterator;
2062 }
2063
2064 /*
2065 * If update is a direct update of head_ref (the reference pointed to
2066 * by HEAD), then add an extra REF_LOG_ONLY update for HEAD.
2067 */
2068 static int split_head_update(struct ref_update *update,
2069 struct ref_transaction *transaction,
2070 const char *head_ref,
2071 struct string_list *affected_refnames,
2072 struct strbuf *err)
2073 {
2074 struct string_list_item *item;
2075 struct ref_update *new_update;
2076
2077 if ((update->flags & REF_LOG_ONLY) ||
2078 (update->flags & REF_ISPRUNING) ||
2079 (update->flags & REF_UPDATE_VIA_HEAD))
2080 return 0;
2081
2082 if (strcmp(update->refname, head_ref))
2083 return 0;
2084
2085 /*
2086 * First make sure that HEAD is not already in the
2087 * transaction. This insertion is O(N) in the transaction
2088 * size, but it happens at most once per transaction.
2089 */
2090 item = string_list_insert(affected_refnames, "HEAD");
2091 if (item->util) {
2092 /* An entry already existed */
2093 strbuf_addf(err,
2094 "multiple updates for 'HEAD' (including one "
2095 "via its referent '%s') are not allowed",
2096 update->refname);
2097 return TRANSACTION_NAME_CONFLICT;
2098 }
2099
2100 new_update = ref_transaction_add_update(
2101 transaction, "HEAD",
2102 update->flags | REF_LOG_ONLY | REF_NODEREF,
2103 update->new_oid.hash, update->old_oid.hash,
2104 update->msg);
2105
2106 item->util = new_update;
2107
2108 return 0;
2109 }
2110
2111 /*
2112 * update is for a symref that points at referent and doesn't have
2113 * REF_NODEREF set. Split it into two updates:
2114 * - The original update, but with REF_LOG_ONLY and REF_NODEREF set
2115 * - A new, separate update for the referent reference
2116 * Note that the new update will itself be subject to splitting when
2117 * the iteration gets to it.
2118 */
2119 static int split_symref_update(struct files_ref_store *refs,
2120 struct ref_update *update,
2121 const char *referent,
2122 struct ref_transaction *transaction,
2123 struct string_list *affected_refnames,
2124 struct strbuf *err)
2125 {
2126 struct string_list_item *item;
2127 struct ref_update *new_update;
2128 unsigned int new_flags;
2129
2130 /*
2131 * First make sure that referent is not already in the
2132 * transaction. This insertion is O(N) in the transaction
2133 * size, but it happens at most once per symref in a
2134 * transaction.
2135 */
2136 item = string_list_insert(affected_refnames, referent);
2137 if (item->util) {
2138 /* An entry already existed */
2139 strbuf_addf(err,
2140 "multiple updates for '%s' (including one "
2141 "via symref '%s') are not allowed",
2142 referent, update->refname);
2143 return TRANSACTION_NAME_CONFLICT;
2144 }
2145
2146 new_flags = update->flags;
2147 if (!strcmp(update->refname, "HEAD")) {
2148 /*
2149 * Record that the new update came via HEAD, so that
2150 * when we process it, split_head_update() doesn't try
2151 * to add another reflog update for HEAD. Note that
2152 * this bit will be propagated if the new_update
2153 * itself needs to be split.
2154 */
2155 new_flags |= REF_UPDATE_VIA_HEAD;
2156 }
2157
2158 new_update = ref_transaction_add_update(
2159 transaction, referent, new_flags,
2160 update->new_oid.hash, update->old_oid.hash,
2161 update->msg);
2162
2163 new_update->parent_update = update;
2164
2165 /*
2166 * Change the symbolic ref update to log only. Also, it
2167 * doesn't need to check its old SHA-1 value, as that will be
2168 * done when new_update is processed.
2169 */
2170 update->flags |= REF_LOG_ONLY | REF_NODEREF;
2171 update->flags &= ~REF_HAVE_OLD;
2172
2173 item->util = new_update;
2174
2175 return 0;
2176 }
2177
2178 /*
2179 * Return the refname under which update was originally requested.
2180 */
2181 static const char *original_update_refname(struct ref_update *update)
2182 {
2183 while (update->parent_update)
2184 update = update->parent_update;
2185
2186 return update->refname;
2187 }
2188
2189 /*
2190 * Check whether the REF_HAVE_OLD and old_oid values stored in update
2191 * are consistent with oid, which is the reference's current value. If
2192 * everything is OK, return 0; otherwise, write an error message to
2193 * err and return -1.
2194 */
2195 static int check_old_oid(struct ref_update *update, struct object_id *oid,
2196 struct strbuf *err)
2197 {
2198 if (!(update->flags & REF_HAVE_OLD) ||
2199 !oidcmp(oid, &update->old_oid))
2200 return 0;
2201
2202 if (is_null_oid(&update->old_oid))
2203 strbuf_addf(err, "cannot lock ref '%s': "
2204 "reference already exists",
2205 original_update_refname(update));
2206 else if (is_null_oid(oid))
2207 strbuf_addf(err, "cannot lock ref '%s': "
2208 "reference is missing but expected %s",
2209 original_update_refname(update),
2210 oid_to_hex(&update->old_oid));
2211 else
2212 strbuf_addf(err, "cannot lock ref '%s': "
2213 "is at %s but expected %s",
2214 original_update_refname(update),
2215 oid_to_hex(oid),
2216 oid_to_hex(&update->old_oid));
2217
2218 return -1;
2219 }
2220
2221 /*
2222 * Prepare for carrying out update:
2223 * - Lock the reference referred to by update.
2224 * - Read the reference under lock.
2225 * - Check that its old SHA-1 value (if specified) is correct, and in
2226 * any case record it in update->lock->old_oid for later use when
2227 * writing the reflog.
2228 * - If it is a symref update without REF_NODEREF, split it up into a
2229 * REF_LOG_ONLY update of the symref and add a separate update for
2230 * the referent to transaction.
2231 * - If it is an update of head_ref, add a corresponding REF_LOG_ONLY
2232 * update of HEAD.
2233 */
2234 static int lock_ref_for_update(struct files_ref_store *refs,
2235 struct ref_update *update,
2236 struct ref_transaction *transaction,
2237 const char *head_ref,
2238 struct string_list *affected_refnames,
2239 struct strbuf *err)
2240 {
2241 struct strbuf referent = STRBUF_INIT;
2242 int mustexist = (update->flags & REF_HAVE_OLD) &&
2243 !is_null_oid(&update->old_oid);
2244 int ret;
2245 struct ref_lock *lock;
2246
2247 files_assert_main_repository(refs, "lock_ref_for_update");
2248
2249 if ((update->flags & REF_HAVE_NEW) && is_null_oid(&update->new_oid))
2250 update->flags |= REF_DELETING;
2251
2252 if (head_ref) {
2253 ret = split_head_update(update, transaction, head_ref,
2254 affected_refnames, err);
2255 if (ret)
2256 return ret;
2257 }
2258
2259 ret = lock_raw_ref(refs, update->refname, mustexist,
2260 affected_refnames, NULL,
2261 &lock, &referent,
2262 &update->type, err);
2263 if (ret) {
2264 char *reason;
2265
2266 reason = strbuf_detach(err, NULL);
2267 strbuf_addf(err, "cannot lock ref '%s': %s",
2268 original_update_refname(update), reason);
2269 free(reason);
2270 return ret;
2271 }
2272
2273 update->backend_data = lock;
2274
2275 if (update->type & REF_ISSYMREF) {
2276 if (update->flags & REF_NODEREF) {
2277 /*
2278 * We won't be reading the referent as part of
2279 * the transaction, so we have to read it here
2280 * to record and possibly check old_sha1:
2281 */
2282 if (refs_read_ref_full(&refs->base,
2283 referent.buf, 0,
2284 lock->old_oid.hash, NULL)) {
2285 if (update->flags & REF_HAVE_OLD) {
2286 strbuf_addf(err, "cannot lock ref '%s': "
2287 "error reading reference",
2288 original_update_refname(update));
2289 return -1;
2290 }
2291 } else if (check_old_oid(update, &lock->old_oid, err)) {
2292 return TRANSACTION_GENERIC_ERROR;
2293 }
2294 } else {
2295 /*
2296 * Create a new update for the reference this
2297 * symref is pointing at. Also, we will record
2298 * and verify old_sha1 for this update as part
2299 * of processing the split-off update, so we
2300 * don't have to do it here.
2301 */
2302 ret = split_symref_update(refs, update,
2303 referent.buf, transaction,
2304 affected_refnames, err);
2305 if (ret)
2306 return ret;
2307 }
2308 } else {
2309 struct ref_update *parent_update;
2310
2311 if (check_old_oid(update, &lock->old_oid, err))
2312 return TRANSACTION_GENERIC_ERROR;
2313
2314 /*
2315 * If this update is happening indirectly because of a
2316 * symref update, record the old SHA-1 in the parent
2317 * update:
2318 */
2319 for (parent_update = update->parent_update;
2320 parent_update;
2321 parent_update = parent_update->parent_update) {
2322 struct ref_lock *parent_lock = parent_update->backend_data;
2323 oidcpy(&parent_lock->old_oid, &lock->old_oid);
2324 }
2325 }
2326
2327 if ((update->flags & REF_HAVE_NEW) &&
2328 !(update->flags & REF_DELETING) &&
2329 !(update->flags & REF_LOG_ONLY)) {
2330 if (!(update->type & REF_ISSYMREF) &&
2331 !oidcmp(&lock->old_oid, &update->new_oid)) {
2332 /*
2333 * The reference already has the desired
2334 * value, so we don't need to write it.
2335 */
2336 } else if (write_ref_to_lockfile(lock, &update->new_oid,
2337 err)) {
2338 char *write_err = strbuf_detach(err, NULL);
2339
2340 /*
2341 * The lock was freed upon failure of
2342 * write_ref_to_lockfile():
2343 */
2344 update->backend_data = NULL;
2345 strbuf_addf(err,
2346 "cannot update ref '%s': %s",
2347 update->refname, write_err);
2348 free(write_err);
2349 return TRANSACTION_GENERIC_ERROR;
2350 } else {
2351 update->flags |= REF_NEEDS_COMMIT;
2352 }
2353 }
2354 if (!(update->flags & REF_NEEDS_COMMIT)) {
2355 /*
2356 * We didn't call write_ref_to_lockfile(), so
2357 * the lockfile is still open. Close it to
2358 * free up the file descriptor:
2359 */
2360 if (close_ref(lock)) {
2361 strbuf_addf(err, "couldn't close '%s.lock'",
2362 update->refname);
2363 return TRANSACTION_GENERIC_ERROR;
2364 }
2365 }
2366 return 0;
2367 }
2368
2369 /*
2370 * Unlock any references in `transaction` that are still locked, and
2371 * mark the transaction closed.
2372 */
2373 static void files_transaction_cleanup(struct ref_transaction *transaction)
2374 {
2375 size_t i;
2376
2377 for (i = 0; i < transaction->nr; i++) {
2378 struct ref_update *update = transaction->updates[i];
2379 struct ref_lock *lock = update->backend_data;
2380
2381 if (lock) {
2382 unlock_ref(lock);
2383 update->backend_data = NULL;
2384 }
2385 }
2386
2387 transaction->state = REF_TRANSACTION_CLOSED;
2388 }
2389
2390 static int files_transaction_prepare(struct ref_store *ref_store,
2391 struct ref_transaction *transaction,
2392 struct strbuf *err)
2393 {
2394 struct files_ref_store *refs =
2395 files_downcast(ref_store, REF_STORE_WRITE,
2396 "ref_transaction_prepare");
2397 size_t i;
2398 int ret = 0;
2399 struct string_list affected_refnames = STRING_LIST_INIT_NODUP;
2400 char *head_ref = NULL;
2401 int head_type;
2402 struct object_id head_oid;
2403
2404 assert(err);
2405
2406 if (!transaction->nr)
2407 goto cleanup;
2408
2409 /*
2410 * Fail if a refname appears more than once in the
2411 * transaction. (If we end up splitting up any updates using
2412 * split_symref_update() or split_head_update(), those
2413 * functions will check that the new updates don't have the
2414 * same refname as any existing ones.)
2415 */
2416 for (i = 0; i < transaction->nr; i++) {
2417 struct ref_update *update = transaction->updates[i];
2418 struct string_list_item *item =
2419 string_list_append(&affected_refnames, update->refname);
2420
2421 /*
2422 * We store a pointer to update in item->util, but at
2423 * the moment we never use the value of this field
2424 * except to check whether it is non-NULL.
2425 */
2426 item->util = update;
2427 }
2428 string_list_sort(&affected_refnames);
2429 if (ref_update_reject_duplicates(&affected_refnames, err)) {
2430 ret = TRANSACTION_GENERIC_ERROR;
2431 goto cleanup;
2432 }
2433
2434 /*
2435 * Special hack: If a branch is updated directly and HEAD
2436 * points to it (may happen on the remote side of a push
2437 * for example) then logically the HEAD reflog should be
2438 * updated too.
2439 *
2440 * A generic solution would require reverse symref lookups,
2441 * but finding all symrefs pointing to a given branch would be
2442 * rather costly for this rare event (the direct update of a
2443 * branch) to be worth it. So let's cheat and check with HEAD
2444 * only, which should cover 99% of all usage scenarios (even
2445 * 100% of the default ones).
2446 *
2447 * So if HEAD is a symbolic reference, then record the name of
2448 * the reference that it points to. If we see an update of
2449 * head_ref within the transaction, then split_head_update()
2450 * arranges for the reflog of HEAD to be updated, too.
2451 */
2452 head_ref = refs_resolve_refdup(ref_store, "HEAD",
2453 RESOLVE_REF_NO_RECURSE,
2454 head_oid.hash, &head_type);
2455
2456 if (head_ref && !(head_type & REF_ISSYMREF)) {
2457 free(head_ref);
2458 head_ref = NULL;
2459 }
2460
2461 /*
2462 * Acquire all locks, verify old values if provided, check
2463 * that new values are valid, and write new values to the
2464 * lockfiles, ready to be activated. Only keep one lockfile
2465 * open at a time to avoid running out of file descriptors.
2466 * Note that lock_ref_for_update() might append more updates
2467 * to the transaction.
2468 */
2469 for (i = 0; i < transaction->nr; i++) {
2470 struct ref_update *update = transaction->updates[i];
2471
2472 ret = lock_ref_for_update(refs, update, transaction,
2473 head_ref, &affected_refnames, err);
2474 if (ret)
2475 break;
2476 }
2477
2478 cleanup:
2479 free(head_ref);
2480 string_list_clear(&affected_refnames, 0);
2481
2482 if (ret)
2483 files_transaction_cleanup(transaction);
2484 else
2485 transaction->state = REF_TRANSACTION_PREPARED;
2486
2487 return ret;
2488 }
2489
2490 static int files_transaction_finish(struct ref_store *ref_store,
2491 struct ref_transaction *transaction,
2492 struct strbuf *err)
2493 {
2494 struct files_ref_store *refs =
2495 files_downcast(ref_store, 0, "ref_transaction_finish");
2496 size_t i;
2497 int ret = 0;
2498 struct string_list refs_to_delete = STRING_LIST_INIT_NODUP;
2499 struct string_list_item *ref_to_delete;
2500 struct strbuf sb = STRBUF_INIT;
2501
2502 assert(err);
2503
2504 if (!transaction->nr) {
2505 transaction->state = REF_TRANSACTION_CLOSED;
2506 return 0;
2507 }
2508
2509 /* Perform updates first so live commits remain referenced */
2510 for (i = 0; i < transaction->nr; i++) {
2511 struct ref_update *update = transaction->updates[i];
2512 struct ref_lock *lock = update->backend_data;
2513
2514 if (update->flags & REF_NEEDS_COMMIT ||
2515 update->flags & REF_LOG_ONLY) {
2516 if (files_log_ref_write(refs,
2517 lock->ref_name,
2518 &lock->old_oid,
2519 &update->new_oid,
2520 update->msg, update->flags,
2521 err)) {
2522 char *old_msg = strbuf_detach(err, NULL);
2523
2524 strbuf_addf(err, "cannot update the ref '%s': %s",
2525 lock->ref_name, old_msg);
2526 free(old_msg);
2527 unlock_ref(lock);
2528 update->backend_data = NULL;
2529 ret = TRANSACTION_GENERIC_ERROR;
2530 goto cleanup;
2531 }
2532 }
2533 if (update->flags & REF_NEEDS_COMMIT) {
2534 clear_loose_ref_cache(refs);
2535 if (commit_ref(lock)) {
2536 strbuf_addf(err, "couldn't set '%s'", lock->ref_name);
2537 unlock_ref(lock);
2538 update->backend_data = NULL;
2539 ret = TRANSACTION_GENERIC_ERROR;
2540 goto cleanup;
2541 }
2542 }
2543 }
2544 /* Perform deletes now that updates are safely completed */
2545 for (i = 0; i < transaction->nr; i++) {
2546 struct ref_update *update = transaction->updates[i];
2547 struct ref_lock *lock = update->backend_data;
2548
2549 if (update->flags & REF_DELETING &&
2550 !(update->flags & REF_LOG_ONLY)) {
2551 if (!(update->type & REF_ISPACKED) ||
2552 update->type & REF_ISSYMREF) {
2553 /* It is a loose reference. */
2554 strbuf_reset(&sb);
2555 files_ref_path(refs, &sb, lock->ref_name);
2556 if (unlink_or_msg(sb.buf, err)) {
2557 ret = TRANSACTION_GENERIC_ERROR;
2558 goto cleanup;
2559 }
2560 update->flags |= REF_DELETED_LOOSE;
2561 }
2562
2563 if (!(update->flags & REF_ISPRUNING))
2564 string_list_append(&refs_to_delete,
2565 lock->ref_name);
2566 }
2567 }
2568
2569 if (repack_without_refs(refs->packed_ref_store, &refs_to_delete, err)) {
2570 ret = TRANSACTION_GENERIC_ERROR;
2571 goto cleanup;
2572 }
2573
2574 /* Delete the reflogs of any references that were deleted: */
2575 for_each_string_list_item(ref_to_delete, &refs_to_delete) {
2576 strbuf_reset(&sb);
2577 files_reflog_path(refs, &sb, ref_to_delete->string);
2578 if (!unlink_or_warn(sb.buf))
2579 try_remove_empty_parents(refs, ref_to_delete->string,
2580 REMOVE_EMPTY_PARENTS_REFLOG);
2581 }
2582
2583 clear_loose_ref_cache(refs);
2584
2585 cleanup:
2586 files_transaction_cleanup(transaction);
2587
2588 for (i = 0; i < transaction->nr; i++) {
2589 struct ref_update *update = transaction->updates[i];
2590
2591 if (update->flags & REF_DELETED_LOOSE) {
2592 /*
2593 * The loose reference was deleted. Delete any
2594 * empty parent directories. (Note that this
2595 * can only work because we have already
2596 * removed the lockfile.)
2597 */
2598 try_remove_empty_parents(refs, update->refname,
2599 REMOVE_EMPTY_PARENTS_REF);
2600 }
2601 }
2602
2603 strbuf_release(&sb);
2604 string_list_clear(&refs_to_delete, 0);
2605 return ret;
2606 }
2607
2608 static int files_transaction_abort(struct ref_store *ref_store,
2609 struct ref_transaction *transaction,
2610 struct strbuf *err)
2611 {
2612 files_transaction_cleanup(transaction);
2613 return 0;
2614 }
2615
2616 static int ref_present(const char *refname,
2617 const struct object_id *oid, int flags, void *cb_data)
2618 {
2619 struct string_list *affected_refnames = cb_data;
2620
2621 return string_list_has_string(affected_refnames, refname);
2622 }
2623
2624 static int files_initial_transaction_commit(struct ref_store *ref_store,
2625 struct ref_transaction *transaction,
2626 struct strbuf *err)
2627 {
2628 struct files_ref_store *refs =
2629 files_downcast(ref_store, REF_STORE_WRITE,
2630 "initial_ref_transaction_commit");
2631 size_t i;
2632 int ret = 0;
2633 struct string_list affected_refnames = STRING_LIST_INIT_NODUP;
2634
2635 assert(err);
2636
2637 if (transaction->state != REF_TRANSACTION_OPEN)
2638 die("BUG: commit called for transaction that is not open");
2639
2640 /* Fail if a refname appears more than once in the transaction: */
2641 for (i = 0; i < transaction->nr; i++)
2642 string_list_append(&affected_refnames,
2643 transaction->updates[i]->refname);
2644 string_list_sort(&affected_refnames);
2645 if (ref_update_reject_duplicates(&affected_refnames, err)) {
2646 ret = TRANSACTION_GENERIC_ERROR;
2647 goto cleanup;
2648 }
2649
2650 /*
2651 * It's really undefined to call this function in an active
2652 * repository or when there are existing references: we are
2653 * only locking and changing packed-refs, so (1) any
2654 * simultaneous processes might try to change a reference at
2655 * the same time we do, and (2) any existing loose versions of
2656 * the references that we are setting would have precedence
2657 * over our values. But some remote helpers create the remote
2658 * "HEAD" and "master" branches before calling this function,
2659 * so here we really only check that none of the references
2660 * that we are creating already exists.
2661 */
2662 if (refs_for_each_rawref(&refs->base, ref_present,
2663 &affected_refnames))
2664 die("BUG: initial ref transaction called with existing refs");
2665
2666 for (i = 0; i < transaction->nr; i++) {
2667 struct ref_update *update = transaction->updates[i];
2668
2669 if ((update->flags & REF_HAVE_OLD) &&
2670 !is_null_oid(&update->old_oid))
2671 die("BUG: initial ref transaction with old_sha1 set");
2672 if (refs_verify_refname_available(&refs->base, update->refname,
2673 &affected_refnames, NULL,
2674 err)) {
2675 ret = TRANSACTION_NAME_CONFLICT;
2676 goto cleanup;
2677 }
2678 }
2679
2680 if (lock_packed_refs(refs->packed_ref_store, 0)) {
2681 strbuf_addf(err, "unable to lock packed-refs file: %s",
2682 strerror(errno));
2683 ret = TRANSACTION_GENERIC_ERROR;
2684 goto cleanup;
2685 }
2686
2687 for (i = 0; i < transaction->nr; i++) {
2688 struct ref_update *update = transaction->updates[i];
2689
2690 if ((update->flags & REF_HAVE_NEW) &&
2691 !is_null_oid(&update->new_oid))
2692 add_packed_ref(refs->packed_ref_store, update->refname,
2693 &update->new_oid);
2694 }
2695
2696 if (commit_packed_refs(refs->packed_ref_store)) {
2697 strbuf_addf(err, "unable to commit packed-refs file: %s",
2698 strerror(errno));
2699 ret = TRANSACTION_GENERIC_ERROR;
2700 goto cleanup;
2701 }
2702
2703 cleanup:
2704 transaction->state = REF_TRANSACTION_CLOSED;
2705 string_list_clear(&affected_refnames, 0);
2706 return ret;
2707 }
2708
2709 struct expire_reflog_cb {
2710 unsigned int flags;
2711 reflog_expiry_should_prune_fn *should_prune_fn;
2712 void *policy_cb;
2713 FILE *newlog;
2714 struct object_id last_kept_oid;
2715 };
2716
2717 static int expire_reflog_ent(struct object_id *ooid, struct object_id *noid,
2718 const char *email, timestamp_t timestamp, int tz,
2719 const char *message, void *cb_data)
2720 {
2721 struct expire_reflog_cb *cb = cb_data;
2722 struct expire_reflog_policy_cb *policy_cb = cb->policy_cb;
2723
2724 if (cb->flags & EXPIRE_REFLOGS_REWRITE)
2725 ooid = &cb->last_kept_oid;
2726
2727 if ((*cb->should_prune_fn)(ooid, noid, email, timestamp, tz,
2728 message, policy_cb)) {
2729 if (!cb->newlog)
2730 printf("would prune %s", message);
2731 else if (cb->flags & EXPIRE_REFLOGS_VERBOSE)
2732 printf("prune %s", message);
2733 } else {
2734 if (cb->newlog) {
2735 fprintf(cb->newlog, "%s %s %s %"PRItime" %+05d\t%s",
2736 oid_to_hex(ooid), oid_to_hex(noid),
2737 email, timestamp, tz, message);
2738 oidcpy(&cb->last_kept_oid, noid);
2739 }
2740 if (cb->flags & EXPIRE_REFLOGS_VERBOSE)
2741 printf("keep %s", message);
2742 }
2743 return 0;
2744 }
2745
2746 static int files_reflog_expire(struct ref_store *ref_store,
2747 const char *refname, const unsigned char *sha1,
2748 unsigned int flags,
2749 reflog_expiry_prepare_fn prepare_fn,
2750 reflog_expiry_should_prune_fn should_prune_fn,
2751 reflog_expiry_cleanup_fn cleanup_fn,
2752 void *policy_cb_data)
2753 {
2754 struct files_ref_store *refs =
2755 files_downcast(ref_store, REF_STORE_WRITE, "reflog_expire");
2756 static struct lock_file reflog_lock;
2757 struct expire_reflog_cb cb;
2758 struct ref_lock *lock;
2759 struct strbuf log_file_sb = STRBUF_INIT;
2760 char *log_file;
2761 int status = 0;
2762 int type;
2763 struct strbuf err = STRBUF_INIT;
2764 struct object_id oid;
2765
2766 memset(&cb, 0, sizeof(cb));
2767 cb.flags = flags;
2768 cb.policy_cb = policy_cb_data;
2769 cb.should_prune_fn = should_prune_fn;
2770
2771 /*
2772 * The reflog file is locked by holding the lock on the
2773 * reference itself, plus we might need to update the
2774 * reference if --updateref was specified:
2775 */
2776 lock = lock_ref_sha1_basic(refs, refname, sha1,
2777 NULL, NULL, REF_NODEREF,
2778 &type, &err);
2779 if (!lock) {
2780 error("cannot lock ref '%s': %s", refname, err.buf);
2781 strbuf_release(&err);
2782 return -1;
2783 }
2784 if (!refs_reflog_exists(ref_store, refname)) {
2785 unlock_ref(lock);
2786 return 0;
2787 }
2788
2789 files_reflog_path(refs, &log_file_sb, refname);
2790 log_file = strbuf_detach(&log_file_sb, NULL);
2791 if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {
2792 /*
2793 * Even though holding $GIT_DIR/logs/$reflog.lock has
2794 * no locking implications, we use the lock_file
2795 * machinery here anyway because it does a lot of the
2796 * work we need, including cleaning up if the program
2797 * exits unexpectedly.
2798 */
2799 if (hold_lock_file_for_update(&reflog_lock, log_file, 0) < 0) {
2800 struct strbuf err = STRBUF_INIT;
2801 unable_to_lock_message(log_file, errno, &err);
2802 error("%s", err.buf);
2803 strbuf_release(&err);
2804 goto failure;
2805 }
2806 cb.newlog = fdopen_lock_file(&reflog_lock, "w");
2807 if (!cb.newlog) {
2808 error("cannot fdopen %s (%s)",
2809 get_lock_file_path(&reflog_lock), strerror(errno));
2810 goto failure;
2811 }
2812 }
2813
2814 hashcpy(oid.hash, sha1);
2815
2816 (*prepare_fn)(refname, &oid, cb.policy_cb);
2817 refs_for_each_reflog_ent(ref_store, refname, expire_reflog_ent, &cb);
2818 (*cleanup_fn)(cb.policy_cb);
2819
2820 if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {
2821 /*
2822 * It doesn't make sense to adjust a reference pointed
2823 * to by a symbolic ref based on expiring entries in
2824 * the symbolic reference's reflog. Nor can we update
2825 * a reference if there are no remaining reflog
2826 * entries.
2827 */
2828 int update = (flags & EXPIRE_REFLOGS_UPDATE_REF) &&
2829 !(type & REF_ISSYMREF) &&
2830 !is_null_oid(&cb.last_kept_oid);
2831
2832 if (close_lock_file(&reflog_lock)) {
2833 status |= error("couldn't write %s: %s", log_file,
2834 strerror(errno));
2835 } else if (update &&
2836 (write_in_full(get_lock_file_fd(lock->lk),
2837 oid_to_hex(&cb.last_kept_oid), GIT_SHA1_HEXSZ) != GIT_SHA1_HEXSZ ||
2838 write_str_in_full(get_lock_file_fd(lock->lk), "\n") != 1 ||
2839 close_ref(lock) < 0)) {
2840 status |= error("couldn't write %s",
2841 get_lock_file_path(lock->lk));
2842 rollback_lock_file(&reflog_lock);
2843 } else if (commit_lock_file(&reflog_lock)) {
2844 status |= error("unable to write reflog '%s' (%s)",
2845 log_file, strerror(errno));
2846 } else if (update && commit_ref(lock)) {
2847 status |= error("couldn't set %s", lock->ref_name);
2848 }
2849 }
2850 free(log_file);
2851 unlock_ref(lock);
2852 return status;
2853
2854 failure:
2855 rollback_lock_file(&reflog_lock);
2856 free(log_file);
2857 unlock_ref(lock);
2858 return -1;
2859 }
2860
2861 static int files_init_db(struct ref_store *ref_store, struct strbuf *err)
2862 {
2863 struct files_ref_store *refs =
2864 files_downcast(ref_store, REF_STORE_WRITE, "init_db");
2865 struct strbuf sb = STRBUF_INIT;
2866
2867 /*
2868 * Create .git/refs/{heads,tags}
2869 */
2870 files_ref_path(refs, &sb, "refs/heads");
2871 safe_create_dir(sb.buf, 1);
2872
2873 strbuf_reset(&sb);
2874 files_ref_path(refs, &sb, "refs/tags");
2875 safe_create_dir(sb.buf, 1);
2876
2877 strbuf_release(&sb);
2878 return 0;
2879 }
2880
2881 struct ref_storage_be refs_be_files = {
2882 NULL,
2883 "files",
2884 files_ref_store_create,
2885 files_init_db,
2886 files_transaction_prepare,
2887 files_transaction_finish,
2888 files_transaction_abort,
2889 files_initial_transaction_commit,
2890
2891 files_pack_refs,
2892 files_peel_ref,
2893 files_create_symref,
2894 files_delete_refs,
2895 files_rename_ref,
2896
2897 files_ref_iterator_begin,
2898 files_read_raw_ref,
2899
2900 files_reflog_iterator_begin,
2901 files_for_each_reflog_ent,
2902 files_for_each_reflog_ent_reverse,
2903 files_reflog_exists,
2904 files_create_reflog,
2905 files_delete_reflog,
2906 files_reflog_expire
2907 };