struct ref_transaction: add a place for backends to store data
[git/git.git] / refs / files-backend.c
1 #include "../cache.h"
2 #include "../config.h"
3 #include "../refs.h"
4 #include "refs-internal.h"
5 #include "ref-cache.h"
6 #include "packed-backend.h"
7 #include "../iterator.h"
8 #include "../dir-iterator.h"
9 #include "../lockfile.h"
10 #include "../object.h"
11 #include "../dir.h"
12
13 struct ref_lock {
14 char *ref_name;
15 struct lock_file *lk;
16 struct object_id old_oid;
17 };
18
19 /*
20 * Future: need to be in "struct repository"
21 * when doing a full libification.
22 */
23 struct files_ref_store {
24 struct ref_store base;
25 unsigned int store_flags;
26
27 char *gitdir;
28 char *gitcommondir;
29
30 struct ref_cache *loose;
31
32 struct ref_store *packed_ref_store;
33 };
34
35 static void clear_loose_ref_cache(struct files_ref_store *refs)
36 {
37 if (refs->loose) {
38 free_ref_cache(refs->loose);
39 refs->loose = NULL;
40 }
41 }
42
43 /*
44 * Create a new submodule ref cache and add it to the internal
45 * set of caches.
46 */
47 static struct ref_store *files_ref_store_create(const char *gitdir,
48 unsigned int flags)
49 {
50 struct files_ref_store *refs = xcalloc(1, sizeof(*refs));
51 struct ref_store *ref_store = (struct ref_store *)refs;
52 struct strbuf sb = STRBUF_INIT;
53
54 base_ref_store_init(ref_store, &refs_be_files);
55 refs->store_flags = flags;
56
57 refs->gitdir = xstrdup(gitdir);
58 get_common_dir_noenv(&sb, gitdir);
59 refs->gitcommondir = strbuf_detach(&sb, NULL);
60 strbuf_addf(&sb, "%s/packed-refs", refs->gitcommondir);
61 refs->packed_ref_store = packed_ref_store_create(sb.buf, flags);
62 strbuf_release(&sb);
63
64 return ref_store;
65 }
66
67 /*
68 * Die if refs is not the main ref store. caller is used in any
69 * necessary error messages.
70 */
71 static void files_assert_main_repository(struct files_ref_store *refs,
72 const char *caller)
73 {
74 if (refs->store_flags & REF_STORE_MAIN)
75 return;
76
77 die("BUG: operation %s only allowed for main ref store", caller);
78 }
79
80 /*
81 * Downcast ref_store to files_ref_store. Die if ref_store is not a
82 * files_ref_store. required_flags is compared with ref_store's
83 * store_flags to ensure the ref_store has all required capabilities.
84 * "caller" is used in any necessary error messages.
85 */
86 static struct files_ref_store *files_downcast(struct ref_store *ref_store,
87 unsigned int required_flags,
88 const char *caller)
89 {
90 struct files_ref_store *refs;
91
92 if (ref_store->be != &refs_be_files)
93 die("BUG: ref_store is type \"%s\" not \"files\" in %s",
94 ref_store->be->name, caller);
95
96 refs = (struct files_ref_store *)ref_store;
97
98 if ((refs->store_flags & required_flags) != required_flags)
99 die("BUG: operation %s requires abilities 0x%x, but only have 0x%x",
100 caller, required_flags, refs->store_flags);
101
102 return refs;
103 }
104
105 static void files_reflog_path(struct files_ref_store *refs,
106 struct strbuf *sb,
107 const char *refname)
108 {
109 if (!refname) {
110 /*
111 * FIXME: of course this is wrong in multi worktree
112 * setting. To be fixed real soon.
113 */
114 strbuf_addf(sb, "%s/logs", refs->gitcommondir);
115 return;
116 }
117
118 switch (ref_type(refname)) {
119 case REF_TYPE_PER_WORKTREE:
120 case REF_TYPE_PSEUDOREF:
121 strbuf_addf(sb, "%s/logs/%s", refs->gitdir, refname);
122 break;
123 case REF_TYPE_NORMAL:
124 strbuf_addf(sb, "%s/logs/%s", refs->gitcommondir, refname);
125 break;
126 default:
127 die("BUG: unknown ref type %d of ref %s",
128 ref_type(refname), refname);
129 }
130 }
131
132 static void files_ref_path(struct files_ref_store *refs,
133 struct strbuf *sb,
134 const char *refname)
135 {
136 switch (ref_type(refname)) {
137 case REF_TYPE_PER_WORKTREE:
138 case REF_TYPE_PSEUDOREF:
139 strbuf_addf(sb, "%s/%s", refs->gitdir, refname);
140 break;
141 case REF_TYPE_NORMAL:
142 strbuf_addf(sb, "%s/%s", refs->gitcommondir, refname);
143 break;
144 default:
145 die("BUG: unknown ref type %d of ref %s",
146 ref_type(refname), refname);
147 }
148 }
149
150 /*
151 * Read the loose references from the namespace dirname into dir
152 * (without recursing). dirname must end with '/'. dir must be the
153 * directory entry corresponding to dirname.
154 */
155 static void loose_fill_ref_dir(struct ref_store *ref_store,
156 struct ref_dir *dir, const char *dirname)
157 {
158 struct files_ref_store *refs =
159 files_downcast(ref_store, REF_STORE_READ, "fill_ref_dir");
160 DIR *d;
161 struct dirent *de;
162 int dirnamelen = strlen(dirname);
163 struct strbuf refname;
164 struct strbuf path = STRBUF_INIT;
165 size_t path_baselen;
166
167 files_ref_path(refs, &path, dirname);
168 path_baselen = path.len;
169
170 d = opendir(path.buf);
171 if (!d) {
172 strbuf_release(&path);
173 return;
174 }
175
176 strbuf_init(&refname, dirnamelen + 257);
177 strbuf_add(&refname, dirname, dirnamelen);
178
179 while ((de = readdir(d)) != NULL) {
180 struct object_id oid;
181 struct stat st;
182 int flag;
183
184 if (de->d_name[0] == '.')
185 continue;
186 if (ends_with(de->d_name, ".lock"))
187 continue;
188 strbuf_addstr(&refname, de->d_name);
189 strbuf_addstr(&path, de->d_name);
190 if (stat(path.buf, &st) < 0) {
191 ; /* silently ignore */
192 } else if (S_ISDIR(st.st_mode)) {
193 strbuf_addch(&refname, '/');
194 add_entry_to_dir(dir,
195 create_dir_entry(dir->cache, refname.buf,
196 refname.len, 1));
197 } else {
198 if (!refs_resolve_ref_unsafe(&refs->base,
199 refname.buf,
200 RESOLVE_REF_READING,
201 oid.hash, &flag)) {
202 oidclr(&oid);
203 flag |= REF_ISBROKEN;
204 } else if (is_null_oid(&oid)) {
205 /*
206 * It is so astronomically unlikely
207 * that NULL_SHA1 is the SHA-1 of an
208 * actual object that we consider its
209 * appearance in a loose reference
210 * file to be repo corruption
211 * (probably due to a software bug).
212 */
213 flag |= REF_ISBROKEN;
214 }
215
216 if (check_refname_format(refname.buf,
217 REFNAME_ALLOW_ONELEVEL)) {
218 if (!refname_is_safe(refname.buf))
219 die("loose refname is dangerous: %s", refname.buf);
220 oidclr(&oid);
221 flag |= REF_BAD_NAME | REF_ISBROKEN;
222 }
223 add_entry_to_dir(dir,
224 create_ref_entry(refname.buf, &oid, flag));
225 }
226 strbuf_setlen(&refname, dirnamelen);
227 strbuf_setlen(&path, path_baselen);
228 }
229 strbuf_release(&refname);
230 strbuf_release(&path);
231 closedir(d);
232
233 /*
234 * Manually add refs/bisect, which, being per-worktree, might
235 * not appear in the directory listing for refs/ in the main
236 * repo.
237 */
238 if (!strcmp(dirname, "refs/")) {
239 int pos = search_ref_dir(dir, "refs/bisect/", 12);
240
241 if (pos < 0) {
242 struct ref_entry *child_entry = create_dir_entry(
243 dir->cache, "refs/bisect/", 12, 1);
244 add_entry_to_dir(dir, child_entry);
245 }
246 }
247 }
248
249 static struct ref_cache *get_loose_ref_cache(struct files_ref_store *refs)
250 {
251 if (!refs->loose) {
252 /*
253 * Mark the top-level directory complete because we
254 * are about to read the only subdirectory that can
255 * hold references:
256 */
257 refs->loose = create_ref_cache(&refs->base, loose_fill_ref_dir);
258
259 /* We're going to fill the top level ourselves: */
260 refs->loose->root->flag &= ~REF_INCOMPLETE;
261
262 /*
263 * Add an incomplete entry for "refs/" (to be filled
264 * lazily):
265 */
266 add_entry_to_dir(get_ref_dir(refs->loose->root),
267 create_dir_entry(refs->loose, "refs/", 5, 1));
268 }
269 return refs->loose;
270 }
271
272 static int files_read_raw_ref(struct ref_store *ref_store,
273 const char *refname, unsigned char *sha1,
274 struct strbuf *referent, unsigned int *type)
275 {
276 struct files_ref_store *refs =
277 files_downcast(ref_store, REF_STORE_READ, "read_raw_ref");
278 struct strbuf sb_contents = STRBUF_INIT;
279 struct strbuf sb_path = STRBUF_INIT;
280 const char *path;
281 const char *buf;
282 struct stat st;
283 int fd;
284 int ret = -1;
285 int save_errno;
286 int remaining_retries = 3;
287
288 *type = 0;
289 strbuf_reset(&sb_path);
290
291 files_ref_path(refs, &sb_path, refname);
292
293 path = sb_path.buf;
294
295 stat_ref:
296 /*
297 * We might have to loop back here to avoid a race
298 * condition: first we lstat() the file, then we try
299 * to read it as a link or as a file. But if somebody
300 * changes the type of the file (file <-> directory
301 * <-> symlink) between the lstat() and reading, then
302 * we don't want to report that as an error but rather
303 * try again starting with the lstat().
304 *
305 * We'll keep a count of the retries, though, just to avoid
306 * any confusing situation sending us into an infinite loop.
307 */
308
309 if (remaining_retries-- <= 0)
310 goto out;
311
312 if (lstat(path, &st) < 0) {
313 if (errno != ENOENT)
314 goto out;
315 if (refs_read_raw_ref(refs->packed_ref_store, refname,
316 sha1, referent, type)) {
317 errno = ENOENT;
318 goto out;
319 }
320 ret = 0;
321 goto out;
322 }
323
324 /* Follow "normalized" - ie "refs/.." symlinks by hand */
325 if (S_ISLNK(st.st_mode)) {
326 strbuf_reset(&sb_contents);
327 if (strbuf_readlink(&sb_contents, path, 0) < 0) {
328 if (errno == ENOENT || errno == EINVAL)
329 /* inconsistent with lstat; retry */
330 goto stat_ref;
331 else
332 goto out;
333 }
334 if (starts_with(sb_contents.buf, "refs/") &&
335 !check_refname_format(sb_contents.buf, 0)) {
336 strbuf_swap(&sb_contents, referent);
337 *type |= REF_ISSYMREF;
338 ret = 0;
339 goto out;
340 }
341 /*
342 * It doesn't look like a refname; fall through to just
343 * treating it like a non-symlink, and reading whatever it
344 * points to.
345 */
346 }
347
348 /* Is it a directory? */
349 if (S_ISDIR(st.st_mode)) {
350 /*
351 * Even though there is a directory where the loose
352 * ref is supposed to be, there could still be a
353 * packed ref:
354 */
355 if (refs_read_raw_ref(refs->packed_ref_store, refname,
356 sha1, referent, type)) {
357 errno = EISDIR;
358 goto out;
359 }
360 ret = 0;
361 goto out;
362 }
363
364 /*
365 * Anything else, just open it and try to use it as
366 * a ref
367 */
368 fd = open(path, O_RDONLY);
369 if (fd < 0) {
370 if (errno == ENOENT && !S_ISLNK(st.st_mode))
371 /* inconsistent with lstat; retry */
372 goto stat_ref;
373 else
374 goto out;
375 }
376 strbuf_reset(&sb_contents);
377 if (strbuf_read(&sb_contents, fd, 256) < 0) {
378 int save_errno = errno;
379 close(fd);
380 errno = save_errno;
381 goto out;
382 }
383 close(fd);
384 strbuf_rtrim(&sb_contents);
385 buf = sb_contents.buf;
386 if (starts_with(buf, "ref:")) {
387 buf += 4;
388 while (isspace(*buf))
389 buf++;
390
391 strbuf_reset(referent);
392 strbuf_addstr(referent, buf);
393 *type |= REF_ISSYMREF;
394 ret = 0;
395 goto out;
396 }
397
398 /*
399 * Please note that FETCH_HEAD has additional
400 * data after the sha.
401 */
402 if (get_sha1_hex(buf, sha1) ||
403 (buf[40] != '\0' && !isspace(buf[40]))) {
404 *type |= REF_ISBROKEN;
405 errno = EINVAL;
406 goto out;
407 }
408
409 ret = 0;
410
411 out:
412 save_errno = errno;
413 strbuf_release(&sb_path);
414 strbuf_release(&sb_contents);
415 errno = save_errno;
416 return ret;
417 }
418
419 static void unlock_ref(struct ref_lock *lock)
420 {
421 /* Do not free lock->lk -- atexit() still looks at them */
422 if (lock->lk)
423 rollback_lock_file(lock->lk);
424 free(lock->ref_name);
425 free(lock);
426 }
427
428 /*
429 * Lock refname, without following symrefs, and set *lock_p to point
430 * at a newly-allocated lock object. Fill in lock->old_oid, referent,
431 * and type similarly to read_raw_ref().
432 *
433 * The caller must verify that refname is a "safe" reference name (in
434 * the sense of refname_is_safe()) before calling this function.
435 *
436 * If the reference doesn't already exist, verify that refname doesn't
437 * have a D/F conflict with any existing references. extras and skip
438 * are passed to refs_verify_refname_available() for this check.
439 *
440 * If mustexist is not set and the reference is not found or is
441 * broken, lock the reference anyway but clear sha1.
442 *
443 * Return 0 on success. On failure, write an error message to err and
444 * return TRANSACTION_NAME_CONFLICT or TRANSACTION_GENERIC_ERROR.
445 *
446 * Implementation note: This function is basically
447 *
448 * lock reference
449 * read_raw_ref()
450 *
451 * but it includes a lot more code to
452 * - Deal with possible races with other processes
453 * - Avoid calling refs_verify_refname_available() when it can be
454 * avoided, namely if we were successfully able to read the ref
455 * - Generate informative error messages in the case of failure
456 */
457 static int lock_raw_ref(struct files_ref_store *refs,
458 const char *refname, int mustexist,
459 const struct string_list *extras,
460 const struct string_list *skip,
461 struct ref_lock **lock_p,
462 struct strbuf *referent,
463 unsigned int *type,
464 struct strbuf *err)
465 {
466 struct ref_lock *lock;
467 struct strbuf ref_file = STRBUF_INIT;
468 int attempts_remaining = 3;
469 int ret = TRANSACTION_GENERIC_ERROR;
470
471 assert(err);
472 files_assert_main_repository(refs, "lock_raw_ref");
473
474 *type = 0;
475
476 /* First lock the file so it can't change out from under us. */
477
478 *lock_p = lock = xcalloc(1, sizeof(*lock));
479
480 lock->ref_name = xstrdup(refname);
481 files_ref_path(refs, &ref_file, refname);
482
483 retry:
484 switch (safe_create_leading_directories(ref_file.buf)) {
485 case SCLD_OK:
486 break; /* success */
487 case SCLD_EXISTS:
488 /*
489 * Suppose refname is "refs/foo/bar". We just failed
490 * to create the containing directory, "refs/foo",
491 * because there was a non-directory in the way. This
492 * indicates a D/F conflict, probably because of
493 * another reference such as "refs/foo". There is no
494 * reason to expect this error to be transitory.
495 */
496 if (refs_verify_refname_available(&refs->base, refname,
497 extras, skip, err)) {
498 if (mustexist) {
499 /*
500 * To the user the relevant error is
501 * that the "mustexist" reference is
502 * missing:
503 */
504 strbuf_reset(err);
505 strbuf_addf(err, "unable to resolve reference '%s'",
506 refname);
507 } else {
508 /*
509 * The error message set by
510 * refs_verify_refname_available() is
511 * OK.
512 */
513 ret = TRANSACTION_NAME_CONFLICT;
514 }
515 } else {
516 /*
517 * The file that is in the way isn't a loose
518 * reference. Report it as a low-level
519 * failure.
520 */
521 strbuf_addf(err, "unable to create lock file %s.lock; "
522 "non-directory in the way",
523 ref_file.buf);
524 }
525 goto error_return;
526 case SCLD_VANISHED:
527 /* Maybe another process was tidying up. Try again. */
528 if (--attempts_remaining > 0)
529 goto retry;
530 /* fall through */
531 default:
532 strbuf_addf(err, "unable to create directory for %s",
533 ref_file.buf);
534 goto error_return;
535 }
536
537 if (!lock->lk)
538 lock->lk = xcalloc(1, sizeof(struct lock_file));
539
540 if (hold_lock_file_for_update_timeout(
541 lock->lk, ref_file.buf, LOCK_NO_DEREF,
542 get_files_ref_lock_timeout_ms()) < 0) {
543 if (errno == ENOENT && --attempts_remaining > 0) {
544 /*
545 * Maybe somebody just deleted one of the
546 * directories leading to ref_file. Try
547 * again:
548 */
549 goto retry;
550 } else {
551 unable_to_lock_message(ref_file.buf, errno, err);
552 goto error_return;
553 }
554 }
555
556 /*
557 * Now we hold the lock and can read the reference without
558 * fear that its value will change.
559 */
560
561 if (files_read_raw_ref(&refs->base, refname,
562 lock->old_oid.hash, referent, type)) {
563 if (errno == ENOENT) {
564 if (mustexist) {
565 /* Garden variety missing reference. */
566 strbuf_addf(err, "unable to resolve reference '%s'",
567 refname);
568 goto error_return;
569 } else {
570 /*
571 * Reference is missing, but that's OK. We
572 * know that there is not a conflict with
573 * another loose reference because
574 * (supposing that we are trying to lock
575 * reference "refs/foo/bar"):
576 *
577 * - We were successfully able to create
578 * the lockfile refs/foo/bar.lock, so we
579 * know there cannot be a loose reference
580 * named "refs/foo".
581 *
582 * - We got ENOENT and not EISDIR, so we
583 * know that there cannot be a loose
584 * reference named "refs/foo/bar/baz".
585 */
586 }
587 } else if (errno == EISDIR) {
588 /*
589 * There is a directory in the way. It might have
590 * contained references that have been deleted. If
591 * we don't require that the reference already
592 * exists, try to remove the directory so that it
593 * doesn't cause trouble when we want to rename the
594 * lockfile into place later.
595 */
596 if (mustexist) {
597 /* Garden variety missing reference. */
598 strbuf_addf(err, "unable to resolve reference '%s'",
599 refname);
600 goto error_return;
601 } else if (remove_dir_recursively(&ref_file,
602 REMOVE_DIR_EMPTY_ONLY)) {
603 if (refs_verify_refname_available(
604 &refs->base, refname,
605 extras, skip, err)) {
606 /*
607 * The error message set by
608 * verify_refname_available() is OK.
609 */
610 ret = TRANSACTION_NAME_CONFLICT;
611 goto error_return;
612 } else {
613 /*
614 * We can't delete the directory,
615 * but we also don't know of any
616 * references that it should
617 * contain.
618 */
619 strbuf_addf(err, "there is a non-empty directory '%s' "
620 "blocking reference '%s'",
621 ref_file.buf, refname);
622 goto error_return;
623 }
624 }
625 } else if (errno == EINVAL && (*type & REF_ISBROKEN)) {
626 strbuf_addf(err, "unable to resolve reference '%s': "
627 "reference broken", refname);
628 goto error_return;
629 } else {
630 strbuf_addf(err, "unable to resolve reference '%s': %s",
631 refname, strerror(errno));
632 goto error_return;
633 }
634
635 /*
636 * If the ref did not exist and we are creating it,
637 * make sure there is no existing packed ref that
638 * conflicts with refname:
639 */
640 if (refs_verify_refname_available(
641 refs->packed_ref_store, refname,
642 extras, skip, err))
643 goto error_return;
644 }
645
646 ret = 0;
647 goto out;
648
649 error_return:
650 unlock_ref(lock);
651 *lock_p = NULL;
652
653 out:
654 strbuf_release(&ref_file);
655 return ret;
656 }
657
658 static int files_peel_ref(struct ref_store *ref_store,
659 const char *refname, unsigned char *sha1)
660 {
661 struct files_ref_store *refs =
662 files_downcast(ref_store, REF_STORE_READ | REF_STORE_ODB,
663 "peel_ref");
664 int flag;
665 unsigned char base[20];
666
667 if (current_ref_iter && current_ref_iter->refname == refname) {
668 struct object_id peeled;
669
670 if (ref_iterator_peel(current_ref_iter, &peeled))
671 return -1;
672 hashcpy(sha1, peeled.hash);
673 return 0;
674 }
675
676 if (refs_read_ref_full(ref_store, refname,
677 RESOLVE_REF_READING, base, &flag))
678 return -1;
679
680 /*
681 * If the reference is packed, read its ref_entry from the
682 * cache in the hope that we already know its peeled value.
683 * We only try this optimization on packed references because
684 * (a) forcing the filling of the loose reference cache could
685 * be expensive and (b) loose references anyway usually do not
686 * have REF_KNOWS_PEELED.
687 */
688 if (flag & REF_ISPACKED &&
689 !refs_peel_ref(refs->packed_ref_store, refname, sha1))
690 return 0;
691
692 return peel_object(base, sha1);
693 }
694
695 struct files_ref_iterator {
696 struct ref_iterator base;
697
698 struct ref_iterator *iter0;
699 unsigned int flags;
700 };
701
702 static int files_ref_iterator_advance(struct ref_iterator *ref_iterator)
703 {
704 struct files_ref_iterator *iter =
705 (struct files_ref_iterator *)ref_iterator;
706 int ok;
707
708 while ((ok = ref_iterator_advance(iter->iter0)) == ITER_OK) {
709 if (iter->flags & DO_FOR_EACH_PER_WORKTREE_ONLY &&
710 ref_type(iter->iter0->refname) != REF_TYPE_PER_WORKTREE)
711 continue;
712
713 if (!(iter->flags & DO_FOR_EACH_INCLUDE_BROKEN) &&
714 !ref_resolves_to_object(iter->iter0->refname,
715 iter->iter0->oid,
716 iter->iter0->flags))
717 continue;
718
719 iter->base.refname = iter->iter0->refname;
720 iter->base.oid = iter->iter0->oid;
721 iter->base.flags = iter->iter0->flags;
722 return ITER_OK;
723 }
724
725 iter->iter0 = NULL;
726 if (ref_iterator_abort(ref_iterator) != ITER_DONE)
727 ok = ITER_ERROR;
728
729 return ok;
730 }
731
732 static int files_ref_iterator_peel(struct ref_iterator *ref_iterator,
733 struct object_id *peeled)
734 {
735 struct files_ref_iterator *iter =
736 (struct files_ref_iterator *)ref_iterator;
737
738 return ref_iterator_peel(iter->iter0, peeled);
739 }
740
741 static int files_ref_iterator_abort(struct ref_iterator *ref_iterator)
742 {
743 struct files_ref_iterator *iter =
744 (struct files_ref_iterator *)ref_iterator;
745 int ok = ITER_DONE;
746
747 if (iter->iter0)
748 ok = ref_iterator_abort(iter->iter0);
749
750 base_ref_iterator_free(ref_iterator);
751 return ok;
752 }
753
754 static struct ref_iterator_vtable files_ref_iterator_vtable = {
755 files_ref_iterator_advance,
756 files_ref_iterator_peel,
757 files_ref_iterator_abort
758 };
759
760 static struct ref_iterator *files_ref_iterator_begin(
761 struct ref_store *ref_store,
762 const char *prefix, unsigned int flags)
763 {
764 struct files_ref_store *refs;
765 struct ref_iterator *loose_iter, *packed_iter;
766 struct files_ref_iterator *iter;
767 struct ref_iterator *ref_iterator;
768 unsigned int required_flags = REF_STORE_READ;
769
770 if (!(flags & DO_FOR_EACH_INCLUDE_BROKEN))
771 required_flags |= REF_STORE_ODB;
772
773 refs = files_downcast(ref_store, required_flags, "ref_iterator_begin");
774
775 iter = xcalloc(1, sizeof(*iter));
776 ref_iterator = &iter->base;
777 base_ref_iterator_init(ref_iterator, &files_ref_iterator_vtable);
778
779 /*
780 * We must make sure that all loose refs are read before
781 * accessing the packed-refs file; this avoids a race
782 * condition if loose refs are migrated to the packed-refs
783 * file by a simultaneous process, but our in-memory view is
784 * from before the migration. We ensure this as follows:
785 * First, we call start the loose refs iteration with its
786 * `prime_ref` argument set to true. This causes the loose
787 * references in the subtree to be pre-read into the cache.
788 * (If they've already been read, that's OK; we only need to
789 * guarantee that they're read before the packed refs, not
790 * *how much* before.) After that, we call
791 * packed_ref_iterator_begin(), which internally checks
792 * whether the packed-ref cache is up to date with what is on
793 * disk, and re-reads it if not.
794 */
795
796 loose_iter = cache_ref_iterator_begin(get_loose_ref_cache(refs),
797 prefix, 1);
798
799 /*
800 * The packed-refs file might contain broken references, for
801 * example an old version of a reference that points at an
802 * object that has since been garbage-collected. This is OK as
803 * long as there is a corresponding loose reference that
804 * overrides it, and we don't want to emit an error message in
805 * this case. So ask the packed_ref_store for all of its
806 * references, and (if needed) do our own check for broken
807 * ones in files_ref_iterator_advance(), after we have merged
808 * the packed and loose references.
809 */
810 packed_iter = refs_ref_iterator_begin(
811 refs->packed_ref_store, prefix, 0,
812 DO_FOR_EACH_INCLUDE_BROKEN);
813
814 iter->iter0 = overlay_ref_iterator_begin(loose_iter, packed_iter);
815 iter->flags = flags;
816
817 return ref_iterator;
818 }
819
820 /*
821 * Verify that the reference locked by lock has the value old_sha1.
822 * Fail if the reference doesn't exist and mustexist is set. Return 0
823 * on success. On error, write an error message to err, set errno, and
824 * return a negative value.
825 */
826 static int verify_lock(struct ref_store *ref_store, struct ref_lock *lock,
827 const unsigned char *old_sha1, int mustexist,
828 struct strbuf *err)
829 {
830 assert(err);
831
832 if (refs_read_ref_full(ref_store, lock->ref_name,
833 mustexist ? RESOLVE_REF_READING : 0,
834 lock->old_oid.hash, NULL)) {
835 if (old_sha1) {
836 int save_errno = errno;
837 strbuf_addf(err, "can't verify ref '%s'", lock->ref_name);
838 errno = save_errno;
839 return -1;
840 } else {
841 oidclr(&lock->old_oid);
842 return 0;
843 }
844 }
845 if (old_sha1 && hashcmp(lock->old_oid.hash, old_sha1)) {
846 strbuf_addf(err, "ref '%s' is at %s but expected %s",
847 lock->ref_name,
848 oid_to_hex(&lock->old_oid),
849 sha1_to_hex(old_sha1));
850 errno = EBUSY;
851 return -1;
852 }
853 return 0;
854 }
855
856 static int remove_empty_directories(struct strbuf *path)
857 {
858 /*
859 * we want to create a file but there is a directory there;
860 * if that is an empty directory (or a directory that contains
861 * only empty directories), remove them.
862 */
863 return remove_dir_recursively(path, REMOVE_DIR_EMPTY_ONLY);
864 }
865
866 static int create_reflock(const char *path, void *cb)
867 {
868 struct lock_file *lk = cb;
869
870 return hold_lock_file_for_update_timeout(
871 lk, path, LOCK_NO_DEREF,
872 get_files_ref_lock_timeout_ms()) < 0 ? -1 : 0;
873 }
874
875 /*
876 * Locks a ref returning the lock on success and NULL on failure.
877 * On failure errno is set to something meaningful.
878 */
879 static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs,
880 const char *refname,
881 const unsigned char *old_sha1,
882 const struct string_list *extras,
883 const struct string_list *skip,
884 unsigned int flags, int *type,
885 struct strbuf *err)
886 {
887 struct strbuf ref_file = STRBUF_INIT;
888 struct ref_lock *lock;
889 int last_errno = 0;
890 int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
891 int resolve_flags = RESOLVE_REF_NO_RECURSE;
892 int resolved;
893
894 files_assert_main_repository(refs, "lock_ref_sha1_basic");
895 assert(err);
896
897 lock = xcalloc(1, sizeof(struct ref_lock));
898
899 if (mustexist)
900 resolve_flags |= RESOLVE_REF_READING;
901 if (flags & REF_DELETING)
902 resolve_flags |= RESOLVE_REF_ALLOW_BAD_NAME;
903
904 files_ref_path(refs, &ref_file, refname);
905 resolved = !!refs_resolve_ref_unsafe(&refs->base,
906 refname, resolve_flags,
907 lock->old_oid.hash, type);
908 if (!resolved && errno == EISDIR) {
909 /*
910 * we are trying to lock foo but we used to
911 * have foo/bar which now does not exist;
912 * it is normal for the empty directory 'foo'
913 * to remain.
914 */
915 if (remove_empty_directories(&ref_file)) {
916 last_errno = errno;
917 if (!refs_verify_refname_available(
918 &refs->base,
919 refname, extras, skip, err))
920 strbuf_addf(err, "there are still refs under '%s'",
921 refname);
922 goto error_return;
923 }
924 resolved = !!refs_resolve_ref_unsafe(&refs->base,
925 refname, resolve_flags,
926 lock->old_oid.hash, type);
927 }
928 if (!resolved) {
929 last_errno = errno;
930 if (last_errno != ENOTDIR ||
931 !refs_verify_refname_available(&refs->base, refname,
932 extras, skip, err))
933 strbuf_addf(err, "unable to resolve reference '%s': %s",
934 refname, strerror(last_errno));
935
936 goto error_return;
937 }
938
939 /*
940 * If the ref did not exist and we are creating it, make sure
941 * there is no existing packed ref whose name begins with our
942 * refname, nor a packed ref whose name is a proper prefix of
943 * our refname.
944 */
945 if (is_null_oid(&lock->old_oid) &&
946 refs_verify_refname_available(refs->packed_ref_store, refname,
947 extras, skip, err)) {
948 last_errno = ENOTDIR;
949 goto error_return;
950 }
951
952 lock->lk = xcalloc(1, sizeof(struct lock_file));
953
954 lock->ref_name = xstrdup(refname);
955
956 if (raceproof_create_file(ref_file.buf, create_reflock, lock->lk)) {
957 last_errno = errno;
958 unable_to_lock_message(ref_file.buf, errno, err);
959 goto error_return;
960 }
961
962 if (verify_lock(&refs->base, lock, old_sha1, mustexist, err)) {
963 last_errno = errno;
964 goto error_return;
965 }
966 goto out;
967
968 error_return:
969 unlock_ref(lock);
970 lock = NULL;
971
972 out:
973 strbuf_release(&ref_file);
974 errno = last_errno;
975 return lock;
976 }
977
978 struct ref_to_prune {
979 struct ref_to_prune *next;
980 unsigned char sha1[20];
981 char name[FLEX_ARRAY];
982 };
983
984 enum {
985 REMOVE_EMPTY_PARENTS_REF = 0x01,
986 REMOVE_EMPTY_PARENTS_REFLOG = 0x02
987 };
988
989 /*
990 * Remove empty parent directories associated with the specified
991 * reference and/or its reflog, but spare [logs/]refs/ and immediate
992 * subdirs. flags is a combination of REMOVE_EMPTY_PARENTS_REF and/or
993 * REMOVE_EMPTY_PARENTS_REFLOG.
994 */
995 static void try_remove_empty_parents(struct files_ref_store *refs,
996 const char *refname,
997 unsigned int flags)
998 {
999 struct strbuf buf = STRBUF_INIT;
1000 struct strbuf sb = STRBUF_INIT;
1001 char *p, *q;
1002 int i;
1003
1004 strbuf_addstr(&buf, refname);
1005 p = buf.buf;
1006 for (i = 0; i < 2; i++) { /* refs/{heads,tags,...}/ */
1007 while (*p && *p != '/')
1008 p++;
1009 /* tolerate duplicate slashes; see check_refname_format() */
1010 while (*p == '/')
1011 p++;
1012 }
1013 q = buf.buf + buf.len;
1014 while (flags & (REMOVE_EMPTY_PARENTS_REF | REMOVE_EMPTY_PARENTS_REFLOG)) {
1015 while (q > p && *q != '/')
1016 q--;
1017 while (q > p && *(q-1) == '/')
1018 q--;
1019 if (q == p)
1020 break;
1021 strbuf_setlen(&buf, q - buf.buf);
1022
1023 strbuf_reset(&sb);
1024 files_ref_path(refs, &sb, buf.buf);
1025 if ((flags & REMOVE_EMPTY_PARENTS_REF) && rmdir(sb.buf))
1026 flags &= ~REMOVE_EMPTY_PARENTS_REF;
1027
1028 strbuf_reset(&sb);
1029 files_reflog_path(refs, &sb, buf.buf);
1030 if ((flags & REMOVE_EMPTY_PARENTS_REFLOG) && rmdir(sb.buf))
1031 flags &= ~REMOVE_EMPTY_PARENTS_REFLOG;
1032 }
1033 strbuf_release(&buf);
1034 strbuf_release(&sb);
1035 }
1036
1037 /* make sure nobody touched the ref, and unlink */
1038 static void prune_ref(struct files_ref_store *refs, struct ref_to_prune *r)
1039 {
1040 struct ref_transaction *transaction;
1041 struct strbuf err = STRBUF_INIT;
1042
1043 if (check_refname_format(r->name, 0))
1044 return;
1045
1046 transaction = ref_store_transaction_begin(&refs->base, &err);
1047 if (!transaction ||
1048 ref_transaction_delete(transaction, r->name, r->sha1,
1049 REF_ISPRUNING | REF_NODEREF, NULL, &err) ||
1050 ref_transaction_commit(transaction, &err)) {
1051 ref_transaction_free(transaction);
1052 error("%s", err.buf);
1053 strbuf_release(&err);
1054 return;
1055 }
1056 ref_transaction_free(transaction);
1057 strbuf_release(&err);
1058 }
1059
1060 static void prune_refs(struct files_ref_store *refs, struct ref_to_prune *r)
1061 {
1062 while (r) {
1063 prune_ref(refs, r);
1064 r = r->next;
1065 }
1066 }
1067
1068 /*
1069 * Return true if the specified reference should be packed.
1070 */
1071 static int should_pack_ref(const char *refname,
1072 const struct object_id *oid, unsigned int ref_flags,
1073 unsigned int pack_flags)
1074 {
1075 /* Do not pack per-worktree refs: */
1076 if (ref_type(refname) != REF_TYPE_NORMAL)
1077 return 0;
1078
1079 /* Do not pack non-tags unless PACK_REFS_ALL is set: */
1080 if (!(pack_flags & PACK_REFS_ALL) && !starts_with(refname, "refs/tags/"))
1081 return 0;
1082
1083 /* Do not pack symbolic refs: */
1084 if (ref_flags & REF_ISSYMREF)
1085 return 0;
1086
1087 /* Do not pack broken refs: */
1088 if (!ref_resolves_to_object(refname, oid, ref_flags))
1089 return 0;
1090
1091 return 1;
1092 }
1093
1094 static int files_pack_refs(struct ref_store *ref_store, unsigned int flags)
1095 {
1096 struct files_ref_store *refs =
1097 files_downcast(ref_store, REF_STORE_WRITE | REF_STORE_ODB,
1098 "pack_refs");
1099 struct ref_iterator *iter;
1100 int ok;
1101 struct ref_to_prune *refs_to_prune = NULL;
1102 struct strbuf err = STRBUF_INIT;
1103
1104 packed_refs_lock(refs->packed_ref_store, LOCK_DIE_ON_ERROR, &err);
1105
1106 iter = cache_ref_iterator_begin(get_loose_ref_cache(refs), NULL, 0);
1107 while ((ok = ref_iterator_advance(iter)) == ITER_OK) {
1108 /*
1109 * If the loose reference can be packed, add an entry
1110 * in the packed ref cache. If the reference should be
1111 * pruned, also add it to refs_to_prune.
1112 */
1113 if (!should_pack_ref(iter->refname, iter->oid, iter->flags,
1114 flags))
1115 continue;
1116
1117 /*
1118 * Create an entry in the packed-refs cache equivalent
1119 * to the one from the loose ref cache, except that
1120 * we don't copy the peeled status, because we want it
1121 * to be re-peeled.
1122 */
1123 add_packed_ref(refs->packed_ref_store, iter->refname, iter->oid);
1124
1125 /* Schedule the loose reference for pruning if requested. */
1126 if ((flags & PACK_REFS_PRUNE)) {
1127 struct ref_to_prune *n;
1128 FLEX_ALLOC_STR(n, name, iter->refname);
1129 hashcpy(n->sha1, iter->oid->hash);
1130 n->next = refs_to_prune;
1131 refs_to_prune = n;
1132 }
1133 }
1134 if (ok != ITER_DONE)
1135 die("error while iterating over references");
1136
1137 if (commit_packed_refs(refs->packed_ref_store, &err))
1138 die("unable to overwrite old ref-pack file: %s", err.buf);
1139 packed_refs_unlock(refs->packed_ref_store);
1140
1141 prune_refs(refs, refs_to_prune);
1142 strbuf_release(&err);
1143 return 0;
1144 }
1145
1146 static int files_delete_refs(struct ref_store *ref_store, const char *msg,
1147 struct string_list *refnames, unsigned int flags)
1148 {
1149 struct files_ref_store *refs =
1150 files_downcast(ref_store, REF_STORE_WRITE, "delete_refs");
1151 struct strbuf err = STRBUF_INIT;
1152 int i, result = 0;
1153
1154 if (!refnames->nr)
1155 return 0;
1156
1157 if (packed_refs_lock(refs->packed_ref_store, 0, &err))
1158 goto error;
1159
1160 if (repack_without_refs(refs->packed_ref_store, refnames, &err)) {
1161 packed_refs_unlock(refs->packed_ref_store);
1162 goto error;
1163 }
1164
1165 packed_refs_unlock(refs->packed_ref_store);
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 strbuf_release(&err);
1175 return result;
1176
1177 error:
1178 /*
1179 * If we failed to rewrite the packed-refs file, then it is
1180 * unsafe to try to remove loose refs, because doing so might
1181 * expose an obsolete packed value for a reference that might
1182 * even point at an object that has been garbage collected.
1183 */
1184 if (refnames->nr == 1)
1185 error(_("could not delete reference %s: %s"),
1186 refnames->items[0].string, err.buf);
1187 else
1188 error(_("could not delete references: %s"), err.buf);
1189
1190 strbuf_release(&err);
1191 return -1;
1192 }
1193
1194 /*
1195 * People using contrib's git-new-workdir have .git/logs/refs ->
1196 * /some/other/path/.git/logs/refs, and that may live on another device.
1197 *
1198 * IOW, to avoid cross device rename errors, the temporary renamed log must
1199 * live into logs/refs.
1200 */
1201 #define TMP_RENAMED_LOG "refs/.tmp-renamed-log"
1202
1203 struct rename_cb {
1204 const char *tmp_renamed_log;
1205 int true_errno;
1206 };
1207
1208 static int rename_tmp_log_callback(const char *path, void *cb_data)
1209 {
1210 struct rename_cb *cb = cb_data;
1211
1212 if (rename(cb->tmp_renamed_log, path)) {
1213 /*
1214 * rename(a, b) when b is an existing directory ought
1215 * to result in ISDIR, but Solaris 5.8 gives ENOTDIR.
1216 * Sheesh. Record the true errno for error reporting,
1217 * but report EISDIR to raceproof_create_file() so
1218 * that it knows to retry.
1219 */
1220 cb->true_errno = errno;
1221 if (errno == ENOTDIR)
1222 errno = EISDIR;
1223 return -1;
1224 } else {
1225 return 0;
1226 }
1227 }
1228
1229 static int rename_tmp_log(struct files_ref_store *refs, const char *newrefname)
1230 {
1231 struct strbuf path = STRBUF_INIT;
1232 struct strbuf tmp = STRBUF_INIT;
1233 struct rename_cb cb;
1234 int ret;
1235
1236 files_reflog_path(refs, &path, newrefname);
1237 files_reflog_path(refs, &tmp, TMP_RENAMED_LOG);
1238 cb.tmp_renamed_log = tmp.buf;
1239 ret = raceproof_create_file(path.buf, rename_tmp_log_callback, &cb);
1240 if (ret) {
1241 if (errno == EISDIR)
1242 error("directory not empty: %s", path.buf);
1243 else
1244 error("unable to move logfile %s to %s: %s",
1245 tmp.buf, path.buf,
1246 strerror(cb.true_errno));
1247 }
1248
1249 strbuf_release(&path);
1250 strbuf_release(&tmp);
1251 return ret;
1252 }
1253
1254 static int write_ref_to_lockfile(struct ref_lock *lock,
1255 const struct object_id *oid, struct strbuf *err);
1256 static int commit_ref_update(struct files_ref_store *refs,
1257 struct ref_lock *lock,
1258 const struct object_id *oid, const char *logmsg,
1259 struct strbuf *err);
1260
1261 static int files_rename_ref(struct ref_store *ref_store,
1262 const char *oldrefname, const char *newrefname,
1263 const char *logmsg)
1264 {
1265 struct files_ref_store *refs =
1266 files_downcast(ref_store, REF_STORE_WRITE, "rename_ref");
1267 struct object_id oid, orig_oid;
1268 int flag = 0, logmoved = 0;
1269 struct ref_lock *lock;
1270 struct stat loginfo;
1271 struct strbuf sb_oldref = STRBUF_INIT;
1272 struct strbuf sb_newref = STRBUF_INIT;
1273 struct strbuf tmp_renamed_log = STRBUF_INIT;
1274 int log, ret;
1275 struct strbuf err = STRBUF_INIT;
1276
1277 files_reflog_path(refs, &sb_oldref, oldrefname);
1278 files_reflog_path(refs, &sb_newref, newrefname);
1279 files_reflog_path(refs, &tmp_renamed_log, TMP_RENAMED_LOG);
1280
1281 log = !lstat(sb_oldref.buf, &loginfo);
1282 if (log && S_ISLNK(loginfo.st_mode)) {
1283 ret = error("reflog for %s is a symlink", oldrefname);
1284 goto out;
1285 }
1286
1287 if (!refs_resolve_ref_unsafe(&refs->base, oldrefname,
1288 RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
1289 orig_oid.hash, &flag)) {
1290 ret = error("refname %s not found", oldrefname);
1291 goto out;
1292 }
1293
1294 if (flag & REF_ISSYMREF) {
1295 ret = error("refname %s is a symbolic ref, renaming it is not supported",
1296 oldrefname);
1297 goto out;
1298 }
1299 if (!refs_rename_ref_available(&refs->base, oldrefname, newrefname)) {
1300 ret = 1;
1301 goto out;
1302 }
1303
1304 if (log && rename(sb_oldref.buf, tmp_renamed_log.buf)) {
1305 ret = error("unable to move logfile logs/%s to logs/"TMP_RENAMED_LOG": %s",
1306 oldrefname, strerror(errno));
1307 goto out;
1308 }
1309
1310 if (refs_delete_ref(&refs->base, logmsg, oldrefname,
1311 orig_oid.hash, REF_NODEREF)) {
1312 error("unable to delete old %s", oldrefname);
1313 goto rollback;
1314 }
1315
1316 /*
1317 * Since we are doing a shallow lookup, oid is not the
1318 * correct value to pass to delete_ref as old_oid. But that
1319 * doesn't matter, because an old_oid check wouldn't add to
1320 * the safety anyway; we want to delete the reference whatever
1321 * its current value.
1322 */
1323 if (!refs_read_ref_full(&refs->base, newrefname,
1324 RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
1325 oid.hash, NULL) &&
1326 refs_delete_ref(&refs->base, NULL, newrefname,
1327 NULL, REF_NODEREF)) {
1328 if (errno == EISDIR) {
1329 struct strbuf path = STRBUF_INIT;
1330 int result;
1331
1332 files_ref_path(refs, &path, newrefname);
1333 result = remove_empty_directories(&path);
1334 strbuf_release(&path);
1335
1336 if (result) {
1337 error("Directory not empty: %s", newrefname);
1338 goto rollback;
1339 }
1340 } else {
1341 error("unable to delete existing %s", newrefname);
1342 goto rollback;
1343 }
1344 }
1345
1346 if (log && rename_tmp_log(refs, newrefname))
1347 goto rollback;
1348
1349 logmoved = log;
1350
1351 lock = lock_ref_sha1_basic(refs, newrefname, NULL, NULL, NULL,
1352 REF_NODEREF, NULL, &err);
1353 if (!lock) {
1354 error("unable to rename '%s' to '%s': %s", oldrefname, newrefname, err.buf);
1355 strbuf_release(&err);
1356 goto rollback;
1357 }
1358 oidcpy(&lock->old_oid, &orig_oid);
1359
1360 if (write_ref_to_lockfile(lock, &orig_oid, &err) ||
1361 commit_ref_update(refs, lock, &orig_oid, logmsg, &err)) {
1362 error("unable to write current sha1 into %s: %s", newrefname, err.buf);
1363 strbuf_release(&err);
1364 goto rollback;
1365 }
1366
1367 ret = 0;
1368 goto out;
1369
1370 rollback:
1371 lock = lock_ref_sha1_basic(refs, oldrefname, NULL, NULL, NULL,
1372 REF_NODEREF, NULL, &err);
1373 if (!lock) {
1374 error("unable to lock %s for rollback: %s", oldrefname, err.buf);
1375 strbuf_release(&err);
1376 goto rollbacklog;
1377 }
1378
1379 flag = log_all_ref_updates;
1380 log_all_ref_updates = LOG_REFS_NONE;
1381 if (write_ref_to_lockfile(lock, &orig_oid, &err) ||
1382 commit_ref_update(refs, lock, &orig_oid, NULL, &err)) {
1383 error("unable to write current sha1 into %s: %s", oldrefname, err.buf);
1384 strbuf_release(&err);
1385 }
1386 log_all_ref_updates = flag;
1387
1388 rollbacklog:
1389 if (logmoved && rename(sb_newref.buf, sb_oldref.buf))
1390 error("unable to restore logfile %s from %s: %s",
1391 oldrefname, newrefname, strerror(errno));
1392 if (!logmoved && log &&
1393 rename(tmp_renamed_log.buf, sb_oldref.buf))
1394 error("unable to restore logfile %s from logs/"TMP_RENAMED_LOG": %s",
1395 oldrefname, strerror(errno));
1396 ret = 1;
1397 out:
1398 strbuf_release(&sb_newref);
1399 strbuf_release(&sb_oldref);
1400 strbuf_release(&tmp_renamed_log);
1401
1402 return ret;
1403 }
1404
1405 static int close_ref(struct ref_lock *lock)
1406 {
1407 if (close_lock_file(lock->lk))
1408 return -1;
1409 return 0;
1410 }
1411
1412 static int commit_ref(struct ref_lock *lock)
1413 {
1414 char *path = get_locked_file_path(lock->lk);
1415 struct stat st;
1416
1417 if (!lstat(path, &st) && S_ISDIR(st.st_mode)) {
1418 /*
1419 * There is a directory at the path we want to rename
1420 * the lockfile to. Hopefully it is empty; try to
1421 * delete it.
1422 */
1423 size_t len = strlen(path);
1424 struct strbuf sb_path = STRBUF_INIT;
1425
1426 strbuf_attach(&sb_path, path, len, len);
1427
1428 /*
1429 * If this fails, commit_lock_file() will also fail
1430 * and will report the problem.
1431 */
1432 remove_empty_directories(&sb_path);
1433 strbuf_release(&sb_path);
1434 } else {
1435 free(path);
1436 }
1437
1438 if (commit_lock_file(lock->lk))
1439 return -1;
1440 return 0;
1441 }
1442
1443 static int open_or_create_logfile(const char *path, void *cb)
1444 {
1445 int *fd = cb;
1446
1447 *fd = open(path, O_APPEND | O_WRONLY | O_CREAT, 0666);
1448 return (*fd < 0) ? -1 : 0;
1449 }
1450
1451 /*
1452 * Create a reflog for a ref. If force_create = 0, only create the
1453 * reflog for certain refs (those for which should_autocreate_reflog
1454 * returns non-zero). Otherwise, create it regardless of the reference
1455 * name. If the logfile already existed or was created, return 0 and
1456 * set *logfd to the file descriptor opened for appending to the file.
1457 * If no logfile exists and we decided not to create one, return 0 and
1458 * set *logfd to -1. On failure, fill in *err, set *logfd to -1, and
1459 * return -1.
1460 */
1461 static int log_ref_setup(struct files_ref_store *refs,
1462 const char *refname, int force_create,
1463 int *logfd, struct strbuf *err)
1464 {
1465 struct strbuf logfile_sb = STRBUF_INIT;
1466 char *logfile;
1467
1468 files_reflog_path(refs, &logfile_sb, refname);
1469 logfile = strbuf_detach(&logfile_sb, NULL);
1470
1471 if (force_create || should_autocreate_reflog(refname)) {
1472 if (raceproof_create_file(logfile, open_or_create_logfile, logfd)) {
1473 if (errno == ENOENT)
1474 strbuf_addf(err, "unable to create directory for '%s': "
1475 "%s", logfile, strerror(errno));
1476 else if (errno == EISDIR)
1477 strbuf_addf(err, "there are still logs under '%s'",
1478 logfile);
1479 else
1480 strbuf_addf(err, "unable to append to '%s': %s",
1481 logfile, strerror(errno));
1482
1483 goto error;
1484 }
1485 } else {
1486 *logfd = open(logfile, O_APPEND | O_WRONLY, 0666);
1487 if (*logfd < 0) {
1488 if (errno == ENOENT || errno == EISDIR) {
1489 /*
1490 * The logfile doesn't already exist,
1491 * but that is not an error; it only
1492 * means that we won't write log
1493 * entries to it.
1494 */
1495 ;
1496 } else {
1497 strbuf_addf(err, "unable to append to '%s': %s",
1498 logfile, strerror(errno));
1499 goto error;
1500 }
1501 }
1502 }
1503
1504 if (*logfd >= 0)
1505 adjust_shared_perm(logfile);
1506
1507 free(logfile);
1508 return 0;
1509
1510 error:
1511 free(logfile);
1512 return -1;
1513 }
1514
1515 static int files_create_reflog(struct ref_store *ref_store,
1516 const char *refname, int force_create,
1517 struct strbuf *err)
1518 {
1519 struct files_ref_store *refs =
1520 files_downcast(ref_store, REF_STORE_WRITE, "create_reflog");
1521 int fd;
1522
1523 if (log_ref_setup(refs, refname, force_create, &fd, err))
1524 return -1;
1525
1526 if (fd >= 0)
1527 close(fd);
1528
1529 return 0;
1530 }
1531
1532 static int log_ref_write_fd(int fd, const struct object_id *old_oid,
1533 const struct object_id *new_oid,
1534 const char *committer, const char *msg)
1535 {
1536 int msglen, written;
1537 unsigned maxlen, len;
1538 char *logrec;
1539
1540 msglen = msg ? strlen(msg) : 0;
1541 maxlen = strlen(committer) + msglen + 100;
1542 logrec = xmalloc(maxlen);
1543 len = xsnprintf(logrec, maxlen, "%s %s %s\n",
1544 oid_to_hex(old_oid),
1545 oid_to_hex(new_oid),
1546 committer);
1547 if (msglen)
1548 len += copy_reflog_msg(logrec + len - 1, msg) - 1;
1549
1550 written = len <= maxlen ? write_in_full(fd, logrec, len) : -1;
1551 free(logrec);
1552 if (written != len)
1553 return -1;
1554
1555 return 0;
1556 }
1557
1558 static int files_log_ref_write(struct files_ref_store *refs,
1559 const char *refname, const struct object_id *old_oid,
1560 const struct object_id *new_oid, const char *msg,
1561 int flags, struct strbuf *err)
1562 {
1563 int logfd, result;
1564
1565 if (log_all_ref_updates == LOG_REFS_UNSET)
1566 log_all_ref_updates = is_bare_repository() ? LOG_REFS_NONE : LOG_REFS_NORMAL;
1567
1568 result = log_ref_setup(refs, refname,
1569 flags & REF_FORCE_CREATE_REFLOG,
1570 &logfd, err);
1571
1572 if (result)
1573 return result;
1574
1575 if (logfd < 0)
1576 return 0;
1577 result = log_ref_write_fd(logfd, old_oid, new_oid,
1578 git_committer_info(0), msg);
1579 if (result) {
1580 struct strbuf sb = STRBUF_INIT;
1581 int save_errno = errno;
1582
1583 files_reflog_path(refs, &sb, refname);
1584 strbuf_addf(err, "unable to append to '%s': %s",
1585 sb.buf, strerror(save_errno));
1586 strbuf_release(&sb);
1587 close(logfd);
1588 return -1;
1589 }
1590 if (close(logfd)) {
1591 struct strbuf sb = STRBUF_INIT;
1592 int save_errno = errno;
1593
1594 files_reflog_path(refs, &sb, refname);
1595 strbuf_addf(err, "unable to append to '%s': %s",
1596 sb.buf, strerror(save_errno));
1597 strbuf_release(&sb);
1598 return -1;
1599 }
1600 return 0;
1601 }
1602
1603 /*
1604 * Write sha1 into the open lockfile, then close the lockfile. On
1605 * errors, rollback the lockfile, fill in *err and
1606 * return -1.
1607 */
1608 static int write_ref_to_lockfile(struct ref_lock *lock,
1609 const struct object_id *oid, struct strbuf *err)
1610 {
1611 static char term = '\n';
1612 struct object *o;
1613 int fd;
1614
1615 o = parse_object(oid);
1616 if (!o) {
1617 strbuf_addf(err,
1618 "trying to write ref '%s' with nonexistent object %s",
1619 lock->ref_name, oid_to_hex(oid));
1620 unlock_ref(lock);
1621 return -1;
1622 }
1623 if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
1624 strbuf_addf(err,
1625 "trying to write non-commit object %s to branch '%s'",
1626 oid_to_hex(oid), lock->ref_name);
1627 unlock_ref(lock);
1628 return -1;
1629 }
1630 fd = get_lock_file_fd(lock->lk);
1631 if (write_in_full(fd, oid_to_hex(oid), GIT_SHA1_HEXSZ) != GIT_SHA1_HEXSZ ||
1632 write_in_full(fd, &term, 1) != 1 ||
1633 close_ref(lock) < 0) {
1634 strbuf_addf(err,
1635 "couldn't write '%s'", get_lock_file_path(lock->lk));
1636 unlock_ref(lock);
1637 return -1;
1638 }
1639 return 0;
1640 }
1641
1642 /*
1643 * Commit a change to a loose reference that has already been written
1644 * to the loose reference lockfile. Also update the reflogs if
1645 * necessary, using the specified lockmsg (which can be NULL).
1646 */
1647 static int commit_ref_update(struct files_ref_store *refs,
1648 struct ref_lock *lock,
1649 const struct object_id *oid, const char *logmsg,
1650 struct strbuf *err)
1651 {
1652 files_assert_main_repository(refs, "commit_ref_update");
1653
1654 clear_loose_ref_cache(refs);
1655 if (files_log_ref_write(refs, lock->ref_name,
1656 &lock->old_oid, oid,
1657 logmsg, 0, err)) {
1658 char *old_msg = strbuf_detach(err, NULL);
1659 strbuf_addf(err, "cannot update the ref '%s': %s",
1660 lock->ref_name, old_msg);
1661 free(old_msg);
1662 unlock_ref(lock);
1663 return -1;
1664 }
1665
1666 if (strcmp(lock->ref_name, "HEAD") != 0) {
1667 /*
1668 * Special hack: If a branch is updated directly and HEAD
1669 * points to it (may happen on the remote side of a push
1670 * for example) then logically the HEAD reflog should be
1671 * updated too.
1672 * A generic solution implies reverse symref information,
1673 * but finding all symrefs pointing to the given branch
1674 * would be rather costly for this rare event (the direct
1675 * update of a branch) to be worth it. So let's cheat and
1676 * check with HEAD only which should cover 99% of all usage
1677 * scenarios (even 100% of the default ones).
1678 */
1679 struct object_id head_oid;
1680 int head_flag;
1681 const char *head_ref;
1682
1683 head_ref = refs_resolve_ref_unsafe(&refs->base, "HEAD",
1684 RESOLVE_REF_READING,
1685 head_oid.hash, &head_flag);
1686 if (head_ref && (head_flag & REF_ISSYMREF) &&
1687 !strcmp(head_ref, lock->ref_name)) {
1688 struct strbuf log_err = STRBUF_INIT;
1689 if (files_log_ref_write(refs, "HEAD",
1690 &lock->old_oid, oid,
1691 logmsg, 0, &log_err)) {
1692 error("%s", log_err.buf);
1693 strbuf_release(&log_err);
1694 }
1695 }
1696 }
1697
1698 if (commit_ref(lock)) {
1699 strbuf_addf(err, "couldn't set '%s'", lock->ref_name);
1700 unlock_ref(lock);
1701 return -1;
1702 }
1703
1704 unlock_ref(lock);
1705 return 0;
1706 }
1707
1708 static int create_ref_symlink(struct ref_lock *lock, const char *target)
1709 {
1710 int ret = -1;
1711 #ifndef NO_SYMLINK_HEAD
1712 char *ref_path = get_locked_file_path(lock->lk);
1713 unlink(ref_path);
1714 ret = symlink(target, ref_path);
1715 free(ref_path);
1716
1717 if (ret)
1718 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
1719 #endif
1720 return ret;
1721 }
1722
1723 static void update_symref_reflog(struct files_ref_store *refs,
1724 struct ref_lock *lock, const char *refname,
1725 const char *target, const char *logmsg)
1726 {
1727 struct strbuf err = STRBUF_INIT;
1728 struct object_id new_oid;
1729 if (logmsg &&
1730 !refs_read_ref_full(&refs->base, target,
1731 RESOLVE_REF_READING, new_oid.hash, NULL) &&
1732 files_log_ref_write(refs, refname, &lock->old_oid,
1733 &new_oid, logmsg, 0, &err)) {
1734 error("%s", err.buf);
1735 strbuf_release(&err);
1736 }
1737 }
1738
1739 static int create_symref_locked(struct files_ref_store *refs,
1740 struct ref_lock *lock, const char *refname,
1741 const char *target, const char *logmsg)
1742 {
1743 if (prefer_symlink_refs && !create_ref_symlink(lock, target)) {
1744 update_symref_reflog(refs, lock, refname, target, logmsg);
1745 return 0;
1746 }
1747
1748 if (!fdopen_lock_file(lock->lk, "w"))
1749 return error("unable to fdopen %s: %s",
1750 lock->lk->tempfile.filename.buf, strerror(errno));
1751
1752 update_symref_reflog(refs, lock, refname, target, logmsg);
1753
1754 /* no error check; commit_ref will check ferror */
1755 fprintf(lock->lk->tempfile.fp, "ref: %s\n", target);
1756 if (commit_ref(lock) < 0)
1757 return error("unable to write symref for %s: %s", refname,
1758 strerror(errno));
1759 return 0;
1760 }
1761
1762 static int files_create_symref(struct ref_store *ref_store,
1763 const char *refname, const char *target,
1764 const char *logmsg)
1765 {
1766 struct files_ref_store *refs =
1767 files_downcast(ref_store, REF_STORE_WRITE, "create_symref");
1768 struct strbuf err = STRBUF_INIT;
1769 struct ref_lock *lock;
1770 int ret;
1771
1772 lock = lock_ref_sha1_basic(refs, refname, NULL,
1773 NULL, NULL, REF_NODEREF, NULL,
1774 &err);
1775 if (!lock) {
1776 error("%s", err.buf);
1777 strbuf_release(&err);
1778 return -1;
1779 }
1780
1781 ret = create_symref_locked(refs, lock, refname, target, logmsg);
1782 unlock_ref(lock);
1783 return ret;
1784 }
1785
1786 static int files_reflog_exists(struct ref_store *ref_store,
1787 const char *refname)
1788 {
1789 struct files_ref_store *refs =
1790 files_downcast(ref_store, REF_STORE_READ, "reflog_exists");
1791 struct strbuf sb = STRBUF_INIT;
1792 struct stat st;
1793 int ret;
1794
1795 files_reflog_path(refs, &sb, refname);
1796 ret = !lstat(sb.buf, &st) && S_ISREG(st.st_mode);
1797 strbuf_release(&sb);
1798 return ret;
1799 }
1800
1801 static int files_delete_reflog(struct ref_store *ref_store,
1802 const char *refname)
1803 {
1804 struct files_ref_store *refs =
1805 files_downcast(ref_store, REF_STORE_WRITE, "delete_reflog");
1806 struct strbuf sb = STRBUF_INIT;
1807 int ret;
1808
1809 files_reflog_path(refs, &sb, refname);
1810 ret = remove_path(sb.buf);
1811 strbuf_release(&sb);
1812 return ret;
1813 }
1814
1815 static int show_one_reflog_ent(struct strbuf *sb, each_reflog_ent_fn fn, void *cb_data)
1816 {
1817 struct object_id ooid, noid;
1818 char *email_end, *message;
1819 timestamp_t timestamp;
1820 int tz;
1821 const char *p = sb->buf;
1822
1823 /* old SP new SP name <email> SP time TAB msg LF */
1824 if (!sb->len || sb->buf[sb->len - 1] != '\n' ||
1825 parse_oid_hex(p, &ooid, &p) || *p++ != ' ' ||
1826 parse_oid_hex(p, &noid, &p) || *p++ != ' ' ||
1827 !(email_end = strchr(p, '>')) ||
1828 email_end[1] != ' ' ||
1829 !(timestamp = parse_timestamp(email_end + 2, &message, 10)) ||
1830 !message || message[0] != ' ' ||
1831 (message[1] != '+' && message[1] != '-') ||
1832 !isdigit(message[2]) || !isdigit(message[3]) ||
1833 !isdigit(message[4]) || !isdigit(message[5]))
1834 return 0; /* corrupt? */
1835 email_end[1] = '\0';
1836 tz = strtol(message + 1, NULL, 10);
1837 if (message[6] != '\t')
1838 message += 6;
1839 else
1840 message += 7;
1841 return fn(&ooid, &noid, p, timestamp, tz, message, cb_data);
1842 }
1843
1844 static char *find_beginning_of_line(char *bob, char *scan)
1845 {
1846 while (bob < scan && *(--scan) != '\n')
1847 ; /* keep scanning backwards */
1848 /*
1849 * Return either beginning of the buffer, or LF at the end of
1850 * the previous line.
1851 */
1852 return scan;
1853 }
1854
1855 static int files_for_each_reflog_ent_reverse(struct ref_store *ref_store,
1856 const char *refname,
1857 each_reflog_ent_fn fn,
1858 void *cb_data)
1859 {
1860 struct files_ref_store *refs =
1861 files_downcast(ref_store, REF_STORE_READ,
1862 "for_each_reflog_ent_reverse");
1863 struct strbuf sb = STRBUF_INIT;
1864 FILE *logfp;
1865 long pos;
1866 int ret = 0, at_tail = 1;
1867
1868 files_reflog_path(refs, &sb, refname);
1869 logfp = fopen(sb.buf, "r");
1870 strbuf_release(&sb);
1871 if (!logfp)
1872 return -1;
1873
1874 /* Jump to the end */
1875 if (fseek(logfp, 0, SEEK_END) < 0)
1876 ret = error("cannot seek back reflog for %s: %s",
1877 refname, strerror(errno));
1878 pos = ftell(logfp);
1879 while (!ret && 0 < pos) {
1880 int cnt;
1881 size_t nread;
1882 char buf[BUFSIZ];
1883 char *endp, *scanp;
1884
1885 /* Fill next block from the end */
1886 cnt = (sizeof(buf) < pos) ? sizeof(buf) : pos;
1887 if (fseek(logfp, pos - cnt, SEEK_SET)) {
1888 ret = error("cannot seek back reflog for %s: %s",
1889 refname, strerror(errno));
1890 break;
1891 }
1892 nread = fread(buf, cnt, 1, logfp);
1893 if (nread != 1) {
1894 ret = error("cannot read %d bytes from reflog for %s: %s",
1895 cnt, refname, strerror(errno));
1896 break;
1897 }
1898 pos -= cnt;
1899
1900 scanp = endp = buf + cnt;
1901 if (at_tail && scanp[-1] == '\n')
1902 /* Looking at the final LF at the end of the file */
1903 scanp--;
1904 at_tail = 0;
1905
1906 while (buf < scanp) {
1907 /*
1908 * terminating LF of the previous line, or the beginning
1909 * of the buffer.
1910 */
1911 char *bp;
1912
1913 bp = find_beginning_of_line(buf, scanp);
1914
1915 if (*bp == '\n') {
1916 /*
1917 * The newline is the end of the previous line,
1918 * so we know we have complete line starting
1919 * at (bp + 1). Prefix it onto any prior data
1920 * we collected for the line and process it.
1921 */
1922 strbuf_splice(&sb, 0, 0, bp + 1, endp - (bp + 1));
1923 scanp = bp;
1924 endp = bp + 1;
1925 ret = show_one_reflog_ent(&sb, fn, cb_data);
1926 strbuf_reset(&sb);
1927 if (ret)
1928 break;
1929 } else if (!pos) {
1930 /*
1931 * We are at the start of the buffer, and the
1932 * start of the file; there is no previous
1933 * line, and we have everything for this one.
1934 * Process it, and we can end the loop.
1935 */
1936 strbuf_splice(&sb, 0, 0, buf, endp - buf);
1937 ret = show_one_reflog_ent(&sb, fn, cb_data);
1938 strbuf_reset(&sb);
1939 break;
1940 }
1941
1942 if (bp == buf) {
1943 /*
1944 * We are at the start of the buffer, and there
1945 * is more file to read backwards. Which means
1946 * we are in the middle of a line. Note that we
1947 * may get here even if *bp was a newline; that
1948 * just means we are at the exact end of the
1949 * previous line, rather than some spot in the
1950 * middle.
1951 *
1952 * Save away what we have to be combined with
1953 * the data from the next read.
1954 */
1955 strbuf_splice(&sb, 0, 0, buf, endp - buf);
1956 break;
1957 }
1958 }
1959
1960 }
1961 if (!ret && sb.len)
1962 die("BUG: reverse reflog parser had leftover data");
1963
1964 fclose(logfp);
1965 strbuf_release(&sb);
1966 return ret;
1967 }
1968
1969 static int files_for_each_reflog_ent(struct ref_store *ref_store,
1970 const char *refname,
1971 each_reflog_ent_fn fn, void *cb_data)
1972 {
1973 struct files_ref_store *refs =
1974 files_downcast(ref_store, REF_STORE_READ,
1975 "for_each_reflog_ent");
1976 FILE *logfp;
1977 struct strbuf sb = STRBUF_INIT;
1978 int ret = 0;
1979
1980 files_reflog_path(refs, &sb, refname);
1981 logfp = fopen(sb.buf, "r");
1982 strbuf_release(&sb);
1983 if (!logfp)
1984 return -1;
1985
1986 while (!ret && !strbuf_getwholeline(&sb, logfp, '\n'))
1987 ret = show_one_reflog_ent(&sb, fn, cb_data);
1988 fclose(logfp);
1989 strbuf_release(&sb);
1990 return ret;
1991 }
1992
1993 struct files_reflog_iterator {
1994 struct ref_iterator base;
1995
1996 struct ref_store *ref_store;
1997 struct dir_iterator *dir_iterator;
1998 struct object_id oid;
1999 };
2000
2001 static int files_reflog_iterator_advance(struct ref_iterator *ref_iterator)
2002 {
2003 struct files_reflog_iterator *iter =
2004 (struct files_reflog_iterator *)ref_iterator;
2005 struct dir_iterator *diter = iter->dir_iterator;
2006 int ok;
2007
2008 while ((ok = dir_iterator_advance(diter)) == ITER_OK) {
2009 int flags;
2010
2011 if (!S_ISREG(diter->st.st_mode))
2012 continue;
2013 if (diter->basename[0] == '.')
2014 continue;
2015 if (ends_with(diter->basename, ".lock"))
2016 continue;
2017
2018 if (refs_read_ref_full(iter->ref_store,
2019 diter->relative_path, 0,
2020 iter->oid.hash, &flags)) {
2021 error("bad ref for %s", diter->path.buf);
2022 continue;
2023 }
2024
2025 iter->base.refname = diter->relative_path;
2026 iter->base.oid = &iter->oid;
2027 iter->base.flags = flags;
2028 return ITER_OK;
2029 }
2030
2031 iter->dir_iterator = NULL;
2032 if (ref_iterator_abort(ref_iterator) == ITER_ERROR)
2033 ok = ITER_ERROR;
2034 return ok;
2035 }
2036
2037 static int files_reflog_iterator_peel(struct ref_iterator *ref_iterator,
2038 struct object_id *peeled)
2039 {
2040 die("BUG: ref_iterator_peel() called for reflog_iterator");
2041 }
2042
2043 static int files_reflog_iterator_abort(struct ref_iterator *ref_iterator)
2044 {
2045 struct files_reflog_iterator *iter =
2046 (struct files_reflog_iterator *)ref_iterator;
2047 int ok = ITER_DONE;
2048
2049 if (iter->dir_iterator)
2050 ok = dir_iterator_abort(iter->dir_iterator);
2051
2052 base_ref_iterator_free(ref_iterator);
2053 return ok;
2054 }
2055
2056 static struct ref_iterator_vtable files_reflog_iterator_vtable = {
2057 files_reflog_iterator_advance,
2058 files_reflog_iterator_peel,
2059 files_reflog_iterator_abort
2060 };
2061
2062 static struct ref_iterator *files_reflog_iterator_begin(struct ref_store *ref_store)
2063 {
2064 struct files_ref_store *refs =
2065 files_downcast(ref_store, REF_STORE_READ,
2066 "reflog_iterator_begin");
2067 struct files_reflog_iterator *iter = xcalloc(1, sizeof(*iter));
2068 struct ref_iterator *ref_iterator = &iter->base;
2069 struct strbuf sb = STRBUF_INIT;
2070
2071 base_ref_iterator_init(ref_iterator, &files_reflog_iterator_vtable);
2072 files_reflog_path(refs, &sb, NULL);
2073 iter->dir_iterator = dir_iterator_begin(sb.buf);
2074 iter->ref_store = ref_store;
2075 strbuf_release(&sb);
2076 return ref_iterator;
2077 }
2078
2079 /*
2080 * If update is a direct update of head_ref (the reference pointed to
2081 * by HEAD), then add an extra REF_LOG_ONLY update for HEAD.
2082 */
2083 static int split_head_update(struct ref_update *update,
2084 struct ref_transaction *transaction,
2085 const char *head_ref,
2086 struct string_list *affected_refnames,
2087 struct strbuf *err)
2088 {
2089 struct string_list_item *item;
2090 struct ref_update *new_update;
2091
2092 if ((update->flags & REF_LOG_ONLY) ||
2093 (update->flags & REF_ISPRUNING) ||
2094 (update->flags & REF_UPDATE_VIA_HEAD))
2095 return 0;
2096
2097 if (strcmp(update->refname, head_ref))
2098 return 0;
2099
2100 /*
2101 * First make sure that HEAD is not already in the
2102 * transaction. This insertion is O(N) in the transaction
2103 * size, but it happens at most once per transaction.
2104 */
2105 item = string_list_insert(affected_refnames, "HEAD");
2106 if (item->util) {
2107 /* An entry already existed */
2108 strbuf_addf(err,
2109 "multiple updates for 'HEAD' (including one "
2110 "via its referent '%s') are not allowed",
2111 update->refname);
2112 return TRANSACTION_NAME_CONFLICT;
2113 }
2114
2115 new_update = ref_transaction_add_update(
2116 transaction, "HEAD",
2117 update->flags | REF_LOG_ONLY | REF_NODEREF,
2118 update->new_oid.hash, update->old_oid.hash,
2119 update->msg);
2120
2121 item->util = new_update;
2122
2123 return 0;
2124 }
2125
2126 /*
2127 * update is for a symref that points at referent and doesn't have
2128 * REF_NODEREF set. Split it into two updates:
2129 * - The original update, but with REF_LOG_ONLY and REF_NODEREF set
2130 * - A new, separate update for the referent reference
2131 * Note that the new update will itself be subject to splitting when
2132 * the iteration gets to it.
2133 */
2134 static int split_symref_update(struct files_ref_store *refs,
2135 struct ref_update *update,
2136 const char *referent,
2137 struct ref_transaction *transaction,
2138 struct string_list *affected_refnames,
2139 struct strbuf *err)
2140 {
2141 struct string_list_item *item;
2142 struct ref_update *new_update;
2143 unsigned int new_flags;
2144
2145 /*
2146 * First make sure that referent is not already in the
2147 * transaction. This insertion is O(N) in the transaction
2148 * size, but it happens at most once per symref in a
2149 * transaction.
2150 */
2151 item = string_list_insert(affected_refnames, referent);
2152 if (item->util) {
2153 /* An entry already existed */
2154 strbuf_addf(err,
2155 "multiple updates for '%s' (including one "
2156 "via symref '%s') are not allowed",
2157 referent, update->refname);
2158 return TRANSACTION_NAME_CONFLICT;
2159 }
2160
2161 new_flags = update->flags;
2162 if (!strcmp(update->refname, "HEAD")) {
2163 /*
2164 * Record that the new update came via HEAD, so that
2165 * when we process it, split_head_update() doesn't try
2166 * to add another reflog update for HEAD. Note that
2167 * this bit will be propagated if the new_update
2168 * itself needs to be split.
2169 */
2170 new_flags |= REF_UPDATE_VIA_HEAD;
2171 }
2172
2173 new_update = ref_transaction_add_update(
2174 transaction, referent, new_flags,
2175 update->new_oid.hash, update->old_oid.hash,
2176 update->msg);
2177
2178 new_update->parent_update = update;
2179
2180 /*
2181 * Change the symbolic ref update to log only. Also, it
2182 * doesn't need to check its old SHA-1 value, as that will be
2183 * done when new_update is processed.
2184 */
2185 update->flags |= REF_LOG_ONLY | REF_NODEREF;
2186 update->flags &= ~REF_HAVE_OLD;
2187
2188 item->util = new_update;
2189
2190 return 0;
2191 }
2192
2193 /*
2194 * Return the refname under which update was originally requested.
2195 */
2196 static const char *original_update_refname(struct ref_update *update)
2197 {
2198 while (update->parent_update)
2199 update = update->parent_update;
2200
2201 return update->refname;
2202 }
2203
2204 /*
2205 * Check whether the REF_HAVE_OLD and old_oid values stored in update
2206 * are consistent with oid, which is the reference's current value. If
2207 * everything is OK, return 0; otherwise, write an error message to
2208 * err and return -1.
2209 */
2210 static int check_old_oid(struct ref_update *update, struct object_id *oid,
2211 struct strbuf *err)
2212 {
2213 if (!(update->flags & REF_HAVE_OLD) ||
2214 !oidcmp(oid, &update->old_oid))
2215 return 0;
2216
2217 if (is_null_oid(&update->old_oid))
2218 strbuf_addf(err, "cannot lock ref '%s': "
2219 "reference already exists",
2220 original_update_refname(update));
2221 else if (is_null_oid(oid))
2222 strbuf_addf(err, "cannot lock ref '%s': "
2223 "reference is missing but expected %s",
2224 original_update_refname(update),
2225 oid_to_hex(&update->old_oid));
2226 else
2227 strbuf_addf(err, "cannot lock ref '%s': "
2228 "is at %s but expected %s",
2229 original_update_refname(update),
2230 oid_to_hex(oid),
2231 oid_to_hex(&update->old_oid));
2232
2233 return -1;
2234 }
2235
2236 /*
2237 * Prepare for carrying out update:
2238 * - Lock the reference referred to by update.
2239 * - Read the reference under lock.
2240 * - Check that its old SHA-1 value (if specified) is correct, and in
2241 * any case record it in update->lock->old_oid for later use when
2242 * writing the reflog.
2243 * - If it is a symref update without REF_NODEREF, split it up into a
2244 * REF_LOG_ONLY update of the symref and add a separate update for
2245 * the referent to transaction.
2246 * - If it is an update of head_ref, add a corresponding REF_LOG_ONLY
2247 * update of HEAD.
2248 */
2249 static int lock_ref_for_update(struct files_ref_store *refs,
2250 struct ref_update *update,
2251 struct ref_transaction *transaction,
2252 const char *head_ref,
2253 struct string_list *affected_refnames,
2254 struct strbuf *err)
2255 {
2256 struct strbuf referent = STRBUF_INIT;
2257 int mustexist = (update->flags & REF_HAVE_OLD) &&
2258 !is_null_oid(&update->old_oid);
2259 int ret;
2260 struct ref_lock *lock;
2261
2262 files_assert_main_repository(refs, "lock_ref_for_update");
2263
2264 if ((update->flags & REF_HAVE_NEW) && is_null_oid(&update->new_oid))
2265 update->flags |= REF_DELETING;
2266
2267 if (head_ref) {
2268 ret = split_head_update(update, transaction, head_ref,
2269 affected_refnames, err);
2270 if (ret)
2271 return ret;
2272 }
2273
2274 ret = lock_raw_ref(refs, update->refname, mustexist,
2275 affected_refnames, NULL,
2276 &lock, &referent,
2277 &update->type, err);
2278 if (ret) {
2279 char *reason;
2280
2281 reason = strbuf_detach(err, NULL);
2282 strbuf_addf(err, "cannot lock ref '%s': %s",
2283 original_update_refname(update), reason);
2284 free(reason);
2285 return ret;
2286 }
2287
2288 update->backend_data = lock;
2289
2290 if (update->type & REF_ISSYMREF) {
2291 if (update->flags & REF_NODEREF) {
2292 /*
2293 * We won't be reading the referent as part of
2294 * the transaction, so we have to read it here
2295 * to record and possibly check old_sha1:
2296 */
2297 if (refs_read_ref_full(&refs->base,
2298 referent.buf, 0,
2299 lock->old_oid.hash, NULL)) {
2300 if (update->flags & REF_HAVE_OLD) {
2301 strbuf_addf(err, "cannot lock ref '%s': "
2302 "error reading reference",
2303 original_update_refname(update));
2304 return -1;
2305 }
2306 } else if (check_old_oid(update, &lock->old_oid, err)) {
2307 return TRANSACTION_GENERIC_ERROR;
2308 }
2309 } else {
2310 /*
2311 * Create a new update for the reference this
2312 * symref is pointing at. Also, we will record
2313 * and verify old_sha1 for this update as part
2314 * of processing the split-off update, so we
2315 * don't have to do it here.
2316 */
2317 ret = split_symref_update(refs, update,
2318 referent.buf, transaction,
2319 affected_refnames, err);
2320 if (ret)
2321 return ret;
2322 }
2323 } else {
2324 struct ref_update *parent_update;
2325
2326 if (check_old_oid(update, &lock->old_oid, err))
2327 return TRANSACTION_GENERIC_ERROR;
2328
2329 /*
2330 * If this update is happening indirectly because of a
2331 * symref update, record the old SHA-1 in the parent
2332 * update:
2333 */
2334 for (parent_update = update->parent_update;
2335 parent_update;
2336 parent_update = parent_update->parent_update) {
2337 struct ref_lock *parent_lock = parent_update->backend_data;
2338 oidcpy(&parent_lock->old_oid, &lock->old_oid);
2339 }
2340 }
2341
2342 if ((update->flags & REF_HAVE_NEW) &&
2343 !(update->flags & REF_DELETING) &&
2344 !(update->flags & REF_LOG_ONLY)) {
2345 if (!(update->type & REF_ISSYMREF) &&
2346 !oidcmp(&lock->old_oid, &update->new_oid)) {
2347 /*
2348 * The reference already has the desired
2349 * value, so we don't need to write it.
2350 */
2351 } else if (write_ref_to_lockfile(lock, &update->new_oid,
2352 err)) {
2353 char *write_err = strbuf_detach(err, NULL);
2354
2355 /*
2356 * The lock was freed upon failure of
2357 * write_ref_to_lockfile():
2358 */
2359 update->backend_data = NULL;
2360 strbuf_addf(err,
2361 "cannot update ref '%s': %s",
2362 update->refname, write_err);
2363 free(write_err);
2364 return TRANSACTION_GENERIC_ERROR;
2365 } else {
2366 update->flags |= REF_NEEDS_COMMIT;
2367 }
2368 }
2369 if (!(update->flags & REF_NEEDS_COMMIT)) {
2370 /*
2371 * We didn't call write_ref_to_lockfile(), so
2372 * the lockfile is still open. Close it to
2373 * free up the file descriptor:
2374 */
2375 if (close_ref(lock)) {
2376 strbuf_addf(err, "couldn't close '%s.lock'",
2377 update->refname);
2378 return TRANSACTION_GENERIC_ERROR;
2379 }
2380 }
2381 return 0;
2382 }
2383
2384 /*
2385 * Unlock any references in `transaction` that are still locked, and
2386 * mark the transaction closed.
2387 */
2388 static void files_transaction_cleanup(struct ref_transaction *transaction)
2389 {
2390 size_t i;
2391
2392 for (i = 0; i < transaction->nr; i++) {
2393 struct ref_update *update = transaction->updates[i];
2394 struct ref_lock *lock = update->backend_data;
2395
2396 if (lock) {
2397 unlock_ref(lock);
2398 update->backend_data = NULL;
2399 }
2400 }
2401
2402 transaction->state = REF_TRANSACTION_CLOSED;
2403 }
2404
2405 static int files_transaction_prepare(struct ref_store *ref_store,
2406 struct ref_transaction *transaction,
2407 struct strbuf *err)
2408 {
2409 struct files_ref_store *refs =
2410 files_downcast(ref_store, REF_STORE_WRITE,
2411 "ref_transaction_prepare");
2412 size_t i;
2413 int ret = 0;
2414 struct string_list affected_refnames = STRING_LIST_INIT_NODUP;
2415 char *head_ref = NULL;
2416 int head_type;
2417 struct object_id head_oid;
2418
2419 assert(err);
2420
2421 if (!transaction->nr)
2422 goto cleanup;
2423
2424 /*
2425 * Fail if a refname appears more than once in the
2426 * transaction. (If we end up splitting up any updates using
2427 * split_symref_update() or split_head_update(), those
2428 * functions will check that the new updates don't have the
2429 * same refname as any existing ones.)
2430 */
2431 for (i = 0; i < transaction->nr; i++) {
2432 struct ref_update *update = transaction->updates[i];
2433 struct string_list_item *item =
2434 string_list_append(&affected_refnames, update->refname);
2435
2436 /*
2437 * We store a pointer to update in item->util, but at
2438 * the moment we never use the value of this field
2439 * except to check whether it is non-NULL.
2440 */
2441 item->util = update;
2442 }
2443 string_list_sort(&affected_refnames);
2444 if (ref_update_reject_duplicates(&affected_refnames, err)) {
2445 ret = TRANSACTION_GENERIC_ERROR;
2446 goto cleanup;
2447 }
2448
2449 /*
2450 * Special hack: If a branch is updated directly and HEAD
2451 * points to it (may happen on the remote side of a push
2452 * for example) then logically the HEAD reflog should be
2453 * updated too.
2454 *
2455 * A generic solution would require reverse symref lookups,
2456 * but finding all symrefs pointing to a given branch would be
2457 * rather costly for this rare event (the direct update of a
2458 * branch) to be worth it. So let's cheat and check with HEAD
2459 * only, which should cover 99% of all usage scenarios (even
2460 * 100% of the default ones).
2461 *
2462 * So if HEAD is a symbolic reference, then record the name of
2463 * the reference that it points to. If we see an update of
2464 * head_ref within the transaction, then split_head_update()
2465 * arranges for the reflog of HEAD to be updated, too.
2466 */
2467 head_ref = refs_resolve_refdup(ref_store, "HEAD",
2468 RESOLVE_REF_NO_RECURSE,
2469 head_oid.hash, &head_type);
2470
2471 if (head_ref && !(head_type & REF_ISSYMREF)) {
2472 FREE_AND_NULL(head_ref);
2473 }
2474
2475 /*
2476 * Acquire all locks, verify old values if provided, check
2477 * that new values are valid, and write new values to the
2478 * lockfiles, ready to be activated. Only keep one lockfile
2479 * open at a time to avoid running out of file descriptors.
2480 * Note that lock_ref_for_update() might append more updates
2481 * to the transaction.
2482 */
2483 for (i = 0; i < transaction->nr; i++) {
2484 struct ref_update *update = transaction->updates[i];
2485
2486 ret = lock_ref_for_update(refs, update, transaction,
2487 head_ref, &affected_refnames, err);
2488 if (ret)
2489 break;
2490 }
2491
2492 cleanup:
2493 free(head_ref);
2494 string_list_clear(&affected_refnames, 0);
2495
2496 if (ret)
2497 files_transaction_cleanup(transaction);
2498 else
2499 transaction->state = REF_TRANSACTION_PREPARED;
2500
2501 return ret;
2502 }
2503
2504 static int files_transaction_finish(struct ref_store *ref_store,
2505 struct ref_transaction *transaction,
2506 struct strbuf *err)
2507 {
2508 struct files_ref_store *refs =
2509 files_downcast(ref_store, 0, "ref_transaction_finish");
2510 size_t i;
2511 int ret = 0;
2512 struct string_list refs_to_delete = STRING_LIST_INIT_NODUP;
2513 struct string_list_item *ref_to_delete;
2514 struct strbuf sb = STRBUF_INIT;
2515
2516 assert(err);
2517
2518 if (!transaction->nr) {
2519 transaction->state = REF_TRANSACTION_CLOSED;
2520 return 0;
2521 }
2522
2523 /* Perform updates first so live commits remain referenced */
2524 for (i = 0; i < transaction->nr; i++) {
2525 struct ref_update *update = transaction->updates[i];
2526 struct ref_lock *lock = update->backend_data;
2527
2528 if (update->flags & REF_NEEDS_COMMIT ||
2529 update->flags & REF_LOG_ONLY) {
2530 if (files_log_ref_write(refs,
2531 lock->ref_name,
2532 &lock->old_oid,
2533 &update->new_oid,
2534 update->msg, update->flags,
2535 err)) {
2536 char *old_msg = strbuf_detach(err, NULL);
2537
2538 strbuf_addf(err, "cannot update the ref '%s': %s",
2539 lock->ref_name, old_msg);
2540 free(old_msg);
2541 unlock_ref(lock);
2542 update->backend_data = NULL;
2543 ret = TRANSACTION_GENERIC_ERROR;
2544 goto cleanup;
2545 }
2546 }
2547 if (update->flags & REF_NEEDS_COMMIT) {
2548 clear_loose_ref_cache(refs);
2549 if (commit_ref(lock)) {
2550 strbuf_addf(err, "couldn't set '%s'", lock->ref_name);
2551 unlock_ref(lock);
2552 update->backend_data = NULL;
2553 ret = TRANSACTION_GENERIC_ERROR;
2554 goto cleanup;
2555 }
2556 }
2557 }
2558 /* Perform deletes now that updates are safely completed */
2559 for (i = 0; i < transaction->nr; i++) {
2560 struct ref_update *update = transaction->updates[i];
2561 struct ref_lock *lock = update->backend_data;
2562
2563 if (update->flags & REF_DELETING &&
2564 !(update->flags & REF_LOG_ONLY)) {
2565 if (!(update->type & REF_ISPACKED) ||
2566 update->type & REF_ISSYMREF) {
2567 /* It is a loose reference. */
2568 strbuf_reset(&sb);
2569 files_ref_path(refs, &sb, lock->ref_name);
2570 if (unlink_or_msg(sb.buf, err)) {
2571 ret = TRANSACTION_GENERIC_ERROR;
2572 goto cleanup;
2573 }
2574 update->flags |= REF_DELETED_LOOSE;
2575 }
2576
2577 if (!(update->flags & REF_ISPRUNING))
2578 string_list_append(&refs_to_delete,
2579 lock->ref_name);
2580 }
2581 }
2582
2583 if (packed_refs_lock(refs->packed_ref_store, 0, err)) {
2584 ret = TRANSACTION_GENERIC_ERROR;
2585 goto cleanup;
2586 }
2587
2588 if (repack_without_refs(refs->packed_ref_store, &refs_to_delete, err)) {
2589 ret = TRANSACTION_GENERIC_ERROR;
2590 packed_refs_unlock(refs->packed_ref_store);
2591 goto cleanup;
2592 }
2593
2594 packed_refs_unlock(refs->packed_ref_store);
2595
2596 /* Delete the reflogs of any references that were deleted: */
2597 for_each_string_list_item(ref_to_delete, &refs_to_delete) {
2598 strbuf_reset(&sb);
2599 files_reflog_path(refs, &sb, ref_to_delete->string);
2600 if (!unlink_or_warn(sb.buf))
2601 try_remove_empty_parents(refs, ref_to_delete->string,
2602 REMOVE_EMPTY_PARENTS_REFLOG);
2603 }
2604
2605 clear_loose_ref_cache(refs);
2606
2607 cleanup:
2608 files_transaction_cleanup(transaction);
2609
2610 for (i = 0; i < transaction->nr; i++) {
2611 struct ref_update *update = transaction->updates[i];
2612
2613 if (update->flags & REF_DELETED_LOOSE) {
2614 /*
2615 * The loose reference was deleted. Delete any
2616 * empty parent directories. (Note that this
2617 * can only work because we have already
2618 * removed the lockfile.)
2619 */
2620 try_remove_empty_parents(refs, update->refname,
2621 REMOVE_EMPTY_PARENTS_REF);
2622 }
2623 }
2624
2625 strbuf_release(&sb);
2626 string_list_clear(&refs_to_delete, 0);
2627 return ret;
2628 }
2629
2630 static int files_transaction_abort(struct ref_store *ref_store,
2631 struct ref_transaction *transaction,
2632 struct strbuf *err)
2633 {
2634 files_transaction_cleanup(transaction);
2635 return 0;
2636 }
2637
2638 static int ref_present(const char *refname,
2639 const struct object_id *oid, int flags, void *cb_data)
2640 {
2641 struct string_list *affected_refnames = cb_data;
2642
2643 return string_list_has_string(affected_refnames, refname);
2644 }
2645
2646 static int files_initial_transaction_commit(struct ref_store *ref_store,
2647 struct ref_transaction *transaction,
2648 struct strbuf *err)
2649 {
2650 struct files_ref_store *refs =
2651 files_downcast(ref_store, REF_STORE_WRITE,
2652 "initial_ref_transaction_commit");
2653 size_t i;
2654 int ret = 0;
2655 struct string_list affected_refnames = STRING_LIST_INIT_NODUP;
2656
2657 assert(err);
2658
2659 if (transaction->state != REF_TRANSACTION_OPEN)
2660 die("BUG: commit called for transaction that is not open");
2661
2662 /* Fail if a refname appears more than once in the transaction: */
2663 for (i = 0; i < transaction->nr; i++)
2664 string_list_append(&affected_refnames,
2665 transaction->updates[i]->refname);
2666 string_list_sort(&affected_refnames);
2667 if (ref_update_reject_duplicates(&affected_refnames, err)) {
2668 ret = TRANSACTION_GENERIC_ERROR;
2669 goto cleanup;
2670 }
2671
2672 /*
2673 * It's really undefined to call this function in an active
2674 * repository or when there are existing references: we are
2675 * only locking and changing packed-refs, so (1) any
2676 * simultaneous processes might try to change a reference at
2677 * the same time we do, and (2) any existing loose versions of
2678 * the references that we are setting would have precedence
2679 * over our values. But some remote helpers create the remote
2680 * "HEAD" and "master" branches before calling this function,
2681 * so here we really only check that none of the references
2682 * that we are creating already exists.
2683 */
2684 if (refs_for_each_rawref(&refs->base, ref_present,
2685 &affected_refnames))
2686 die("BUG: initial ref transaction called with existing refs");
2687
2688 for (i = 0; i < transaction->nr; i++) {
2689 struct ref_update *update = transaction->updates[i];
2690
2691 if ((update->flags & REF_HAVE_OLD) &&
2692 !is_null_oid(&update->old_oid))
2693 die("BUG: initial ref transaction with old_sha1 set");
2694 if (refs_verify_refname_available(&refs->base, update->refname,
2695 &affected_refnames, NULL,
2696 err)) {
2697 ret = TRANSACTION_NAME_CONFLICT;
2698 goto cleanup;
2699 }
2700 }
2701
2702 if (packed_refs_lock(refs->packed_ref_store, 0, err)) {
2703 ret = TRANSACTION_GENERIC_ERROR;
2704 goto cleanup;
2705 }
2706
2707 for (i = 0; i < transaction->nr; i++) {
2708 struct ref_update *update = transaction->updates[i];
2709
2710 if ((update->flags & REF_HAVE_NEW) &&
2711 !is_null_oid(&update->new_oid))
2712 add_packed_ref(refs->packed_ref_store, update->refname,
2713 &update->new_oid);
2714 }
2715
2716 if (commit_packed_refs(refs->packed_ref_store, err)) {
2717 ret = TRANSACTION_GENERIC_ERROR;
2718 goto cleanup;
2719 }
2720
2721 cleanup:
2722 packed_refs_unlock(refs->packed_ref_store);
2723 transaction->state = REF_TRANSACTION_CLOSED;
2724 string_list_clear(&affected_refnames, 0);
2725 return ret;
2726 }
2727
2728 struct expire_reflog_cb {
2729 unsigned int flags;
2730 reflog_expiry_should_prune_fn *should_prune_fn;
2731 void *policy_cb;
2732 FILE *newlog;
2733 struct object_id last_kept_oid;
2734 };
2735
2736 static int expire_reflog_ent(struct object_id *ooid, struct object_id *noid,
2737 const char *email, timestamp_t timestamp, int tz,
2738 const char *message, void *cb_data)
2739 {
2740 struct expire_reflog_cb *cb = cb_data;
2741 struct expire_reflog_policy_cb *policy_cb = cb->policy_cb;
2742
2743 if (cb->flags & EXPIRE_REFLOGS_REWRITE)
2744 ooid = &cb->last_kept_oid;
2745
2746 if ((*cb->should_prune_fn)(ooid, noid, email, timestamp, tz,
2747 message, policy_cb)) {
2748 if (!cb->newlog)
2749 printf("would prune %s", message);
2750 else if (cb->flags & EXPIRE_REFLOGS_VERBOSE)
2751 printf("prune %s", message);
2752 } else {
2753 if (cb->newlog) {
2754 fprintf(cb->newlog, "%s %s %s %"PRItime" %+05d\t%s",
2755 oid_to_hex(ooid), oid_to_hex(noid),
2756 email, timestamp, tz, message);
2757 oidcpy(&cb->last_kept_oid, noid);
2758 }
2759 if (cb->flags & EXPIRE_REFLOGS_VERBOSE)
2760 printf("keep %s", message);
2761 }
2762 return 0;
2763 }
2764
2765 static int files_reflog_expire(struct ref_store *ref_store,
2766 const char *refname, const unsigned char *sha1,
2767 unsigned int flags,
2768 reflog_expiry_prepare_fn prepare_fn,
2769 reflog_expiry_should_prune_fn should_prune_fn,
2770 reflog_expiry_cleanup_fn cleanup_fn,
2771 void *policy_cb_data)
2772 {
2773 struct files_ref_store *refs =
2774 files_downcast(ref_store, REF_STORE_WRITE, "reflog_expire");
2775 static struct lock_file reflog_lock;
2776 struct expire_reflog_cb cb;
2777 struct ref_lock *lock;
2778 struct strbuf log_file_sb = STRBUF_INIT;
2779 char *log_file;
2780 int status = 0;
2781 int type;
2782 struct strbuf err = STRBUF_INIT;
2783 struct object_id oid;
2784
2785 memset(&cb, 0, sizeof(cb));
2786 cb.flags = flags;
2787 cb.policy_cb = policy_cb_data;
2788 cb.should_prune_fn = should_prune_fn;
2789
2790 /*
2791 * The reflog file is locked by holding the lock on the
2792 * reference itself, plus we might need to update the
2793 * reference if --updateref was specified:
2794 */
2795 lock = lock_ref_sha1_basic(refs, refname, sha1,
2796 NULL, NULL, REF_NODEREF,
2797 &type, &err);
2798 if (!lock) {
2799 error("cannot lock ref '%s': %s", refname, err.buf);
2800 strbuf_release(&err);
2801 return -1;
2802 }
2803 if (!refs_reflog_exists(ref_store, refname)) {
2804 unlock_ref(lock);
2805 return 0;
2806 }
2807
2808 files_reflog_path(refs, &log_file_sb, refname);
2809 log_file = strbuf_detach(&log_file_sb, NULL);
2810 if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {
2811 /*
2812 * Even though holding $GIT_DIR/logs/$reflog.lock has
2813 * no locking implications, we use the lock_file
2814 * machinery here anyway because it does a lot of the
2815 * work we need, including cleaning up if the program
2816 * exits unexpectedly.
2817 */
2818 if (hold_lock_file_for_update(&reflog_lock, log_file, 0) < 0) {
2819 struct strbuf err = STRBUF_INIT;
2820 unable_to_lock_message(log_file, errno, &err);
2821 error("%s", err.buf);
2822 strbuf_release(&err);
2823 goto failure;
2824 }
2825 cb.newlog = fdopen_lock_file(&reflog_lock, "w");
2826 if (!cb.newlog) {
2827 error("cannot fdopen %s (%s)",
2828 get_lock_file_path(&reflog_lock), strerror(errno));
2829 goto failure;
2830 }
2831 }
2832
2833 hashcpy(oid.hash, sha1);
2834
2835 (*prepare_fn)(refname, &oid, cb.policy_cb);
2836 refs_for_each_reflog_ent(ref_store, refname, expire_reflog_ent, &cb);
2837 (*cleanup_fn)(cb.policy_cb);
2838
2839 if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {
2840 /*
2841 * It doesn't make sense to adjust a reference pointed
2842 * to by a symbolic ref based on expiring entries in
2843 * the symbolic reference's reflog. Nor can we update
2844 * a reference if there are no remaining reflog
2845 * entries.
2846 */
2847 int update = (flags & EXPIRE_REFLOGS_UPDATE_REF) &&
2848 !(type & REF_ISSYMREF) &&
2849 !is_null_oid(&cb.last_kept_oid);
2850
2851 if (close_lock_file(&reflog_lock)) {
2852 status |= error("couldn't write %s: %s", log_file,
2853 strerror(errno));
2854 } else if (update &&
2855 (write_in_full(get_lock_file_fd(lock->lk),
2856 oid_to_hex(&cb.last_kept_oid), GIT_SHA1_HEXSZ) != GIT_SHA1_HEXSZ ||
2857 write_str_in_full(get_lock_file_fd(lock->lk), "\n") != 1 ||
2858 close_ref(lock) < 0)) {
2859 status |= error("couldn't write %s",
2860 get_lock_file_path(lock->lk));
2861 rollback_lock_file(&reflog_lock);
2862 } else if (commit_lock_file(&reflog_lock)) {
2863 status |= error("unable to write reflog '%s' (%s)",
2864 log_file, strerror(errno));
2865 } else if (update && commit_ref(lock)) {
2866 status |= error("couldn't set %s", lock->ref_name);
2867 }
2868 }
2869 free(log_file);
2870 unlock_ref(lock);
2871 return status;
2872
2873 failure:
2874 rollback_lock_file(&reflog_lock);
2875 free(log_file);
2876 unlock_ref(lock);
2877 return -1;
2878 }
2879
2880 static int files_init_db(struct ref_store *ref_store, struct strbuf *err)
2881 {
2882 struct files_ref_store *refs =
2883 files_downcast(ref_store, REF_STORE_WRITE, "init_db");
2884 struct strbuf sb = STRBUF_INIT;
2885
2886 /*
2887 * Create .git/refs/{heads,tags}
2888 */
2889 files_ref_path(refs, &sb, "refs/heads");
2890 safe_create_dir(sb.buf, 1);
2891
2892 strbuf_reset(&sb);
2893 files_ref_path(refs, &sb, "refs/tags");
2894 safe_create_dir(sb.buf, 1);
2895
2896 strbuf_release(&sb);
2897 return 0;
2898 }
2899
2900 struct ref_storage_be refs_be_files = {
2901 NULL,
2902 "files",
2903 files_ref_store_create,
2904 files_init_db,
2905 files_transaction_prepare,
2906 files_transaction_finish,
2907 files_transaction_abort,
2908 files_initial_transaction_commit,
2909
2910 files_pack_refs,
2911 files_peel_ref,
2912 files_create_symref,
2913 files_delete_refs,
2914 files_rename_ref,
2915
2916 files_ref_iterator_begin,
2917 files_read_raw_ref,
2918
2919 files_reflog_iterator_begin,
2920 files_for_each_reflog_ent,
2921 files_for_each_reflog_ent_reverse,
2922 files_reflog_exists,
2923 files_create_reflog,
2924 files_delete_reflog,
2925 files_reflog_expire
2926 };