contrib/subtree: ensure only one rev is provided
[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 #include "../chdir-notify.h"
13 #include "worktree.h"
14
15 /*
16 * This backend uses the following flags in `ref_update::flags` for
17 * internal bookkeeping purposes. Their numerical values must not
18 * conflict with REF_NO_DEREF, REF_FORCE_CREATE_REFLOG, REF_HAVE_NEW,
19 * REF_HAVE_OLD, or REF_IS_PRUNING, which are also stored in
20 * `ref_update::flags`.
21 */
22
23 /*
24 * Used as a flag in ref_update::flags when a loose ref is being
25 * pruned. This flag must only be used when REF_NO_DEREF is set.
26 */
27 #define REF_IS_PRUNING (1 << 4)
28
29 /*
30 * Flag passed to lock_ref_sha1_basic() telling it to tolerate broken
31 * refs (i.e., because the reference is about to be deleted anyway).
32 */
33 #define REF_DELETING (1 << 5)
34
35 /*
36 * Used as a flag in ref_update::flags when the lockfile needs to be
37 * committed.
38 */
39 #define REF_NEEDS_COMMIT (1 << 6)
40
41 /*
42 * Used as a flag in ref_update::flags when we want to log a ref
43 * update but not actually perform it. This is used when a symbolic
44 * ref update is split up.
45 */
46 #define REF_LOG_ONLY (1 << 7)
47
48 /*
49 * Used as a flag in ref_update::flags when the ref_update was via an
50 * update to HEAD.
51 */
52 #define REF_UPDATE_VIA_HEAD (1 << 8)
53
54 /*
55 * Used as a flag in ref_update::flags when the loose reference has
56 * been deleted.
57 */
58 #define REF_DELETED_LOOSE (1 << 9)
59
60 struct ref_lock {
61 char *ref_name;
62 struct lock_file lk;
63 struct object_id old_oid;
64 };
65
66 struct files_ref_store {
67 struct ref_store base;
68 unsigned int store_flags;
69
70 char *gitdir;
71 char *gitcommondir;
72
73 struct ref_cache *loose;
74
75 struct ref_store *packed_ref_store;
76 };
77
78 static void clear_loose_ref_cache(struct files_ref_store *refs)
79 {
80 if (refs->loose) {
81 free_ref_cache(refs->loose);
82 refs->loose = NULL;
83 }
84 }
85
86 /*
87 * Create a new submodule ref cache and add it to the internal
88 * set of caches.
89 */
90 static struct ref_store *files_ref_store_create(const char *gitdir,
91 unsigned int flags)
92 {
93 struct files_ref_store *refs = xcalloc(1, sizeof(*refs));
94 struct ref_store *ref_store = (struct ref_store *)refs;
95 struct strbuf sb = STRBUF_INIT;
96
97 base_ref_store_init(ref_store, &refs_be_files);
98 refs->store_flags = flags;
99
100 refs->gitdir = xstrdup(gitdir);
101 get_common_dir_noenv(&sb, gitdir);
102 refs->gitcommondir = strbuf_detach(&sb, NULL);
103 strbuf_addf(&sb, "%s/packed-refs", refs->gitcommondir);
104 refs->packed_ref_store = packed_ref_store_create(sb.buf, flags);
105 strbuf_release(&sb);
106
107 chdir_notify_reparent("files-backend $GIT_DIR",
108 &refs->gitdir);
109 chdir_notify_reparent("files-backend $GIT_COMMONDIR",
110 &refs->gitcommondir);
111
112 return ref_store;
113 }
114
115 /*
116 * Die if refs is not the main ref store. caller is used in any
117 * necessary error messages.
118 */
119 static void files_assert_main_repository(struct files_ref_store *refs,
120 const char *caller)
121 {
122 if (refs->store_flags & REF_STORE_MAIN)
123 return;
124
125 BUG("operation %s only allowed for main ref store", caller);
126 }
127
128 /*
129 * Downcast ref_store to files_ref_store. Die if ref_store is not a
130 * files_ref_store. required_flags is compared with ref_store's
131 * store_flags to ensure the ref_store has all required capabilities.
132 * "caller" is used in any necessary error messages.
133 */
134 static struct files_ref_store *files_downcast(struct ref_store *ref_store,
135 unsigned int required_flags,
136 const char *caller)
137 {
138 struct files_ref_store *refs;
139
140 if (ref_store->be != &refs_be_files)
141 BUG("ref_store is type \"%s\" not \"files\" in %s",
142 ref_store->be->name, caller);
143
144 refs = (struct files_ref_store *)ref_store;
145
146 if ((refs->store_flags & required_flags) != required_flags)
147 BUG("operation %s requires abilities 0x%x, but only have 0x%x",
148 caller, required_flags, refs->store_flags);
149
150 return refs;
151 }
152
153 static void files_reflog_path_other_worktrees(struct files_ref_store *refs,
154 struct strbuf *sb,
155 const char *refname)
156 {
157 const char *real_ref;
158 const char *worktree_name;
159 int length;
160
161 if (parse_worktree_ref(refname, &worktree_name, &length, &real_ref))
162 BUG("refname %s is not a other-worktree ref", refname);
163
164 if (worktree_name)
165 strbuf_addf(sb, "%s/worktrees/%.*s/logs/%s", refs->gitcommondir,
166 length, worktree_name, real_ref);
167 else
168 strbuf_addf(sb, "%s/logs/%s", refs->gitcommondir,
169 real_ref);
170 }
171
172 static void files_reflog_path(struct files_ref_store *refs,
173 struct strbuf *sb,
174 const char *refname)
175 {
176 switch (ref_type(refname)) {
177 case REF_TYPE_PER_WORKTREE:
178 case REF_TYPE_PSEUDOREF:
179 strbuf_addf(sb, "%s/logs/%s", refs->gitdir, refname);
180 break;
181 case REF_TYPE_OTHER_PSEUDOREF:
182 case REF_TYPE_MAIN_PSEUDOREF:
183 files_reflog_path_other_worktrees(refs, sb, refname);
184 break;
185 case REF_TYPE_NORMAL:
186 strbuf_addf(sb, "%s/logs/%s", refs->gitcommondir, refname);
187 break;
188 default:
189 BUG("unknown ref type %d of ref %s",
190 ref_type(refname), refname);
191 }
192 }
193
194 static void files_ref_path(struct files_ref_store *refs,
195 struct strbuf *sb,
196 const char *refname)
197 {
198 switch (ref_type(refname)) {
199 case REF_TYPE_PER_WORKTREE:
200 case REF_TYPE_PSEUDOREF:
201 strbuf_addf(sb, "%s/%s", refs->gitdir, refname);
202 break;
203 case REF_TYPE_MAIN_PSEUDOREF:
204 if (!skip_prefix(refname, "main-worktree/", &refname))
205 BUG("ref %s is not a main pseudoref", refname);
206 /* fallthrough */
207 case REF_TYPE_OTHER_PSEUDOREF:
208 case REF_TYPE_NORMAL:
209 strbuf_addf(sb, "%s/%s", refs->gitcommondir, refname);
210 break;
211 default:
212 BUG("unknown ref type %d of ref %s",
213 ref_type(refname), refname);
214 }
215 }
216
217 /*
218 * Read the loose references from the namespace dirname into dir
219 * (without recursing). dirname must end with '/'. dir must be the
220 * directory entry corresponding to dirname.
221 */
222 static void loose_fill_ref_dir(struct ref_store *ref_store,
223 struct ref_dir *dir, const char *dirname)
224 {
225 struct files_ref_store *refs =
226 files_downcast(ref_store, REF_STORE_READ, "fill_ref_dir");
227 DIR *d;
228 struct dirent *de;
229 int dirnamelen = strlen(dirname);
230 struct strbuf refname;
231 struct strbuf path = STRBUF_INIT;
232 size_t path_baselen;
233
234 files_ref_path(refs, &path, dirname);
235 path_baselen = path.len;
236
237 d = opendir(path.buf);
238 if (!d) {
239 strbuf_release(&path);
240 return;
241 }
242
243 strbuf_init(&refname, dirnamelen + 257);
244 strbuf_add(&refname, dirname, dirnamelen);
245
246 while ((de = readdir(d)) != NULL) {
247 struct object_id oid;
248 struct stat st;
249 int flag;
250
251 if (de->d_name[0] == '.')
252 continue;
253 if (ends_with(de->d_name, ".lock"))
254 continue;
255 strbuf_addstr(&refname, de->d_name);
256 strbuf_addstr(&path, de->d_name);
257 if (stat(path.buf, &st) < 0) {
258 ; /* silently ignore */
259 } else if (S_ISDIR(st.st_mode)) {
260 strbuf_addch(&refname, '/');
261 add_entry_to_dir(dir,
262 create_dir_entry(dir->cache, refname.buf,
263 refname.len, 1));
264 } else {
265 if (!refs_resolve_ref_unsafe(&refs->base,
266 refname.buf,
267 RESOLVE_REF_READING,
268 &oid, &flag)) {
269 oidclr(&oid);
270 flag |= REF_ISBROKEN;
271 } else if (is_null_oid(&oid)) {
272 /*
273 * It is so astronomically unlikely
274 * that null_oid is the OID of an
275 * actual object that we consider its
276 * appearance in a loose reference
277 * file to be repo corruption
278 * (probably due to a software bug).
279 */
280 flag |= REF_ISBROKEN;
281 }
282
283 if (check_refname_format(refname.buf,
284 REFNAME_ALLOW_ONELEVEL)) {
285 if (!refname_is_safe(refname.buf))
286 die("loose refname is dangerous: %s", refname.buf);
287 oidclr(&oid);
288 flag |= REF_BAD_NAME | REF_ISBROKEN;
289 }
290 add_entry_to_dir(dir,
291 create_ref_entry(refname.buf, &oid, flag));
292 }
293 strbuf_setlen(&refname, dirnamelen);
294 strbuf_setlen(&path, path_baselen);
295 }
296 strbuf_release(&refname);
297 strbuf_release(&path);
298 closedir(d);
299
300 /*
301 * Manually add refs/bisect and refs/worktree, which, being
302 * per-worktree, might not appear in the directory listing for
303 * refs/ in the main repo.
304 */
305 if (!strcmp(dirname, "refs/")) {
306 int pos = search_ref_dir(dir, "refs/bisect/", 12);
307
308 if (pos < 0) {
309 struct ref_entry *child_entry = create_dir_entry(
310 dir->cache, "refs/bisect/", 12, 1);
311 add_entry_to_dir(dir, child_entry);
312 }
313
314 pos = search_ref_dir(dir, "refs/worktree/", 11);
315
316 if (pos < 0) {
317 struct ref_entry *child_entry = create_dir_entry(
318 dir->cache, "refs/worktree/", 11, 1);
319 add_entry_to_dir(dir, child_entry);
320 }
321 }
322 }
323
324 static struct ref_cache *get_loose_ref_cache(struct files_ref_store *refs)
325 {
326 if (!refs->loose) {
327 /*
328 * Mark the top-level directory complete because we
329 * are about to read the only subdirectory that can
330 * hold references:
331 */
332 refs->loose = create_ref_cache(&refs->base, loose_fill_ref_dir);
333
334 /* We're going to fill the top level ourselves: */
335 refs->loose->root->flag &= ~REF_INCOMPLETE;
336
337 /*
338 * Add an incomplete entry for "refs/" (to be filled
339 * lazily):
340 */
341 add_entry_to_dir(get_ref_dir(refs->loose->root),
342 create_dir_entry(refs->loose, "refs/", 5, 1));
343 }
344 return refs->loose;
345 }
346
347 static int files_read_raw_ref(struct ref_store *ref_store,
348 const char *refname, struct object_id *oid,
349 struct strbuf *referent, unsigned int *type)
350 {
351 struct files_ref_store *refs =
352 files_downcast(ref_store, REF_STORE_READ, "read_raw_ref");
353 struct strbuf sb_contents = STRBUF_INIT;
354 struct strbuf sb_path = STRBUF_INIT;
355 const char *path;
356 const char *buf;
357 const char *p;
358 struct stat st;
359 int fd;
360 int ret = -1;
361 int save_errno;
362 int remaining_retries = 3;
363
364 *type = 0;
365 strbuf_reset(&sb_path);
366
367 files_ref_path(refs, &sb_path, refname);
368
369 path = sb_path.buf;
370
371 stat_ref:
372 /*
373 * We might have to loop back here to avoid a race
374 * condition: first we lstat() the file, then we try
375 * to read it as a link or as a file. But if somebody
376 * changes the type of the file (file <-> directory
377 * <-> symlink) between the lstat() and reading, then
378 * we don't want to report that as an error but rather
379 * try again starting with the lstat().
380 *
381 * We'll keep a count of the retries, though, just to avoid
382 * any confusing situation sending us into an infinite loop.
383 */
384
385 if (remaining_retries-- <= 0)
386 goto out;
387
388 if (lstat(path, &st) < 0) {
389 if (errno != ENOENT)
390 goto out;
391 if (refs_read_raw_ref(refs->packed_ref_store, refname,
392 oid, referent, type)) {
393 errno = ENOENT;
394 goto out;
395 }
396 ret = 0;
397 goto out;
398 }
399
400 /* Follow "normalized" - ie "refs/.." symlinks by hand */
401 if (S_ISLNK(st.st_mode)) {
402 strbuf_reset(&sb_contents);
403 if (strbuf_readlink(&sb_contents, path, st.st_size) < 0) {
404 if (errno == ENOENT || errno == EINVAL)
405 /* inconsistent with lstat; retry */
406 goto stat_ref;
407 else
408 goto out;
409 }
410 if (starts_with(sb_contents.buf, "refs/") &&
411 !check_refname_format(sb_contents.buf, 0)) {
412 strbuf_swap(&sb_contents, referent);
413 *type |= REF_ISSYMREF;
414 ret = 0;
415 goto out;
416 }
417 /*
418 * It doesn't look like a refname; fall through to just
419 * treating it like a non-symlink, and reading whatever it
420 * points to.
421 */
422 }
423
424 /* Is it a directory? */
425 if (S_ISDIR(st.st_mode)) {
426 /*
427 * Even though there is a directory where the loose
428 * ref is supposed to be, there could still be a
429 * packed ref:
430 */
431 if (refs_read_raw_ref(refs->packed_ref_store, refname,
432 oid, referent, type)) {
433 errno = EISDIR;
434 goto out;
435 }
436 ret = 0;
437 goto out;
438 }
439
440 /*
441 * Anything else, just open it and try to use it as
442 * a ref
443 */
444 fd = open(path, O_RDONLY);
445 if (fd < 0) {
446 if (errno == ENOENT && !S_ISLNK(st.st_mode))
447 /* inconsistent with lstat; retry */
448 goto stat_ref;
449 else
450 goto out;
451 }
452 strbuf_reset(&sb_contents);
453 if (strbuf_read(&sb_contents, fd, 256) < 0) {
454 int save_errno = errno;
455 close(fd);
456 errno = save_errno;
457 goto out;
458 }
459 close(fd);
460 strbuf_rtrim(&sb_contents);
461 buf = sb_contents.buf;
462 if (starts_with(buf, "ref:")) {
463 buf += 4;
464 while (isspace(*buf))
465 buf++;
466
467 strbuf_reset(referent);
468 strbuf_addstr(referent, buf);
469 *type |= REF_ISSYMREF;
470 ret = 0;
471 goto out;
472 }
473
474 /*
475 * Please note that FETCH_HEAD has additional
476 * data after the sha.
477 */
478 if (parse_oid_hex(buf, oid, &p) ||
479 (*p != '\0' && !isspace(*p))) {
480 *type |= REF_ISBROKEN;
481 errno = EINVAL;
482 goto out;
483 }
484
485 ret = 0;
486
487 out:
488 save_errno = errno;
489 strbuf_release(&sb_path);
490 strbuf_release(&sb_contents);
491 errno = save_errno;
492 return ret;
493 }
494
495 static void unlock_ref(struct ref_lock *lock)
496 {
497 rollback_lock_file(&lock->lk);
498 free(lock->ref_name);
499 free(lock);
500 }
501
502 /*
503 * Lock refname, without following symrefs, and set *lock_p to point
504 * at a newly-allocated lock object. Fill in lock->old_oid, referent,
505 * and type similarly to read_raw_ref().
506 *
507 * The caller must verify that refname is a "safe" reference name (in
508 * the sense of refname_is_safe()) before calling this function.
509 *
510 * If the reference doesn't already exist, verify that refname doesn't
511 * have a D/F conflict with any existing references. extras and skip
512 * are passed to refs_verify_refname_available() for this check.
513 *
514 * If mustexist is not set and the reference is not found or is
515 * broken, lock the reference anyway but clear old_oid.
516 *
517 * Return 0 on success. On failure, write an error message to err and
518 * return TRANSACTION_NAME_CONFLICT or TRANSACTION_GENERIC_ERROR.
519 *
520 * Implementation note: This function is basically
521 *
522 * lock reference
523 * read_raw_ref()
524 *
525 * but it includes a lot more code to
526 * - Deal with possible races with other processes
527 * - Avoid calling refs_verify_refname_available() when it can be
528 * avoided, namely if we were successfully able to read the ref
529 * - Generate informative error messages in the case of failure
530 */
531 static int lock_raw_ref(struct files_ref_store *refs,
532 const char *refname, int mustexist,
533 const struct string_list *extras,
534 const struct string_list *skip,
535 struct ref_lock **lock_p,
536 struct strbuf *referent,
537 unsigned int *type,
538 struct strbuf *err)
539 {
540 struct ref_lock *lock;
541 struct strbuf ref_file = STRBUF_INIT;
542 int attempts_remaining = 3;
543 int ret = TRANSACTION_GENERIC_ERROR;
544
545 assert(err);
546 files_assert_main_repository(refs, "lock_raw_ref");
547
548 *type = 0;
549
550 /* First lock the file so it can't change out from under us. */
551
552 *lock_p = lock = xcalloc(1, sizeof(*lock));
553
554 lock->ref_name = xstrdup(refname);
555 files_ref_path(refs, &ref_file, refname);
556
557 retry:
558 switch (safe_create_leading_directories(ref_file.buf)) {
559 case SCLD_OK:
560 break; /* success */
561 case SCLD_EXISTS:
562 /*
563 * Suppose refname is "refs/foo/bar". We just failed
564 * to create the containing directory, "refs/foo",
565 * because there was a non-directory in the way. This
566 * indicates a D/F conflict, probably because of
567 * another reference such as "refs/foo". There is no
568 * reason to expect this error to be transitory.
569 */
570 if (refs_verify_refname_available(&refs->base, refname,
571 extras, skip, err)) {
572 if (mustexist) {
573 /*
574 * To the user the relevant error is
575 * that the "mustexist" reference is
576 * missing:
577 */
578 strbuf_reset(err);
579 strbuf_addf(err, "unable to resolve reference '%s'",
580 refname);
581 } else {
582 /*
583 * The error message set by
584 * refs_verify_refname_available() is
585 * OK.
586 */
587 ret = TRANSACTION_NAME_CONFLICT;
588 }
589 } else {
590 /*
591 * The file that is in the way isn't a loose
592 * reference. Report it as a low-level
593 * failure.
594 */
595 strbuf_addf(err, "unable to create lock file %s.lock; "
596 "non-directory in the way",
597 ref_file.buf);
598 }
599 goto error_return;
600 case SCLD_VANISHED:
601 /* Maybe another process was tidying up. Try again. */
602 if (--attempts_remaining > 0)
603 goto retry;
604 /* fall through */
605 default:
606 strbuf_addf(err, "unable to create directory for %s",
607 ref_file.buf);
608 goto error_return;
609 }
610
611 if (hold_lock_file_for_update_timeout(
612 &lock->lk, ref_file.buf, LOCK_NO_DEREF,
613 get_files_ref_lock_timeout_ms()) < 0) {
614 if (errno == ENOENT && --attempts_remaining > 0) {
615 /*
616 * Maybe somebody just deleted one of the
617 * directories leading to ref_file. Try
618 * again:
619 */
620 goto retry;
621 } else {
622 unable_to_lock_message(ref_file.buf, errno, err);
623 goto error_return;
624 }
625 }
626
627 /*
628 * Now we hold the lock and can read the reference without
629 * fear that its value will change.
630 */
631
632 if (files_read_raw_ref(&refs->base, refname,
633 &lock->old_oid, referent, type)) {
634 if (errno == ENOENT) {
635 if (mustexist) {
636 /* Garden variety missing reference. */
637 strbuf_addf(err, "unable to resolve reference '%s'",
638 refname);
639 goto error_return;
640 } else {
641 /*
642 * Reference is missing, but that's OK. We
643 * know that there is not a conflict with
644 * another loose reference because
645 * (supposing that we are trying to lock
646 * reference "refs/foo/bar"):
647 *
648 * - We were successfully able to create
649 * the lockfile refs/foo/bar.lock, so we
650 * know there cannot be a loose reference
651 * named "refs/foo".
652 *
653 * - We got ENOENT and not EISDIR, so we
654 * know that there cannot be a loose
655 * reference named "refs/foo/bar/baz".
656 */
657 }
658 } else if (errno == EISDIR) {
659 /*
660 * There is a directory in the way. It might have
661 * contained references that have been deleted. If
662 * we don't require that the reference already
663 * exists, try to remove the directory so that it
664 * doesn't cause trouble when we want to rename the
665 * lockfile into place later.
666 */
667 if (mustexist) {
668 /* Garden variety missing reference. */
669 strbuf_addf(err, "unable to resolve reference '%s'",
670 refname);
671 goto error_return;
672 } else if (remove_dir_recursively(&ref_file,
673 REMOVE_DIR_EMPTY_ONLY)) {
674 if (refs_verify_refname_available(
675 &refs->base, refname,
676 extras, skip, err)) {
677 /*
678 * The error message set by
679 * verify_refname_available() is OK.
680 */
681 ret = TRANSACTION_NAME_CONFLICT;
682 goto error_return;
683 } else {
684 /*
685 * We can't delete the directory,
686 * but we also don't know of any
687 * references that it should
688 * contain.
689 */
690 strbuf_addf(err, "there is a non-empty directory '%s' "
691 "blocking reference '%s'",
692 ref_file.buf, refname);
693 goto error_return;
694 }
695 }
696 } else if (errno == EINVAL && (*type & REF_ISBROKEN)) {
697 strbuf_addf(err, "unable to resolve reference '%s': "
698 "reference broken", refname);
699 goto error_return;
700 } else {
701 strbuf_addf(err, "unable to resolve reference '%s': %s",
702 refname, strerror(errno));
703 goto error_return;
704 }
705
706 /*
707 * If the ref did not exist and we are creating it,
708 * make sure there is no existing packed ref that
709 * conflicts with refname:
710 */
711 if (refs_verify_refname_available(
712 refs->packed_ref_store, refname,
713 extras, skip, err))
714 goto error_return;
715 }
716
717 ret = 0;
718 goto out;
719
720 error_return:
721 unlock_ref(lock);
722 *lock_p = NULL;
723
724 out:
725 strbuf_release(&ref_file);
726 return ret;
727 }
728
729 struct files_ref_iterator {
730 struct ref_iterator base;
731
732 struct ref_iterator *iter0;
733 unsigned int flags;
734 };
735
736 static int files_ref_iterator_advance(struct ref_iterator *ref_iterator)
737 {
738 struct files_ref_iterator *iter =
739 (struct files_ref_iterator *)ref_iterator;
740 int ok;
741
742 while ((ok = ref_iterator_advance(iter->iter0)) == ITER_OK) {
743 if (iter->flags & DO_FOR_EACH_PER_WORKTREE_ONLY &&
744 ref_type(iter->iter0->refname) != REF_TYPE_PER_WORKTREE)
745 continue;
746
747 if (!(iter->flags & DO_FOR_EACH_INCLUDE_BROKEN) &&
748 !ref_resolves_to_object(iter->iter0->refname,
749 iter->iter0->oid,
750 iter->iter0->flags))
751 continue;
752
753 iter->base.refname = iter->iter0->refname;
754 iter->base.oid = iter->iter0->oid;
755 iter->base.flags = iter->iter0->flags;
756 return ITER_OK;
757 }
758
759 iter->iter0 = NULL;
760 if (ref_iterator_abort(ref_iterator) != ITER_DONE)
761 ok = ITER_ERROR;
762
763 return ok;
764 }
765
766 static int files_ref_iterator_peel(struct ref_iterator *ref_iterator,
767 struct object_id *peeled)
768 {
769 struct files_ref_iterator *iter =
770 (struct files_ref_iterator *)ref_iterator;
771
772 return ref_iterator_peel(iter->iter0, peeled);
773 }
774
775 static int files_ref_iterator_abort(struct ref_iterator *ref_iterator)
776 {
777 struct files_ref_iterator *iter =
778 (struct files_ref_iterator *)ref_iterator;
779 int ok = ITER_DONE;
780
781 if (iter->iter0)
782 ok = ref_iterator_abort(iter->iter0);
783
784 base_ref_iterator_free(ref_iterator);
785 return ok;
786 }
787
788 static struct ref_iterator_vtable files_ref_iterator_vtable = {
789 files_ref_iterator_advance,
790 files_ref_iterator_peel,
791 files_ref_iterator_abort
792 };
793
794 static struct ref_iterator *files_ref_iterator_begin(
795 struct ref_store *ref_store,
796 const char *prefix, unsigned int flags)
797 {
798 struct files_ref_store *refs;
799 struct ref_iterator *loose_iter, *packed_iter, *overlay_iter;
800 struct files_ref_iterator *iter;
801 struct ref_iterator *ref_iterator;
802 unsigned int required_flags = REF_STORE_READ;
803
804 if (!(flags & DO_FOR_EACH_INCLUDE_BROKEN))
805 required_flags |= REF_STORE_ODB;
806
807 refs = files_downcast(ref_store, required_flags, "ref_iterator_begin");
808
809 /*
810 * We must make sure that all loose refs are read before
811 * accessing the packed-refs file; this avoids a race
812 * condition if loose refs are migrated to the packed-refs
813 * file by a simultaneous process, but our in-memory view is
814 * from before the migration. We ensure this as follows:
815 * First, we call start the loose refs iteration with its
816 * `prime_ref` argument set to true. This causes the loose
817 * references in the subtree to be pre-read into the cache.
818 * (If they've already been read, that's OK; we only need to
819 * guarantee that they're read before the packed refs, not
820 * *how much* before.) After that, we call
821 * packed_ref_iterator_begin(), which internally checks
822 * whether the packed-ref cache is up to date with what is on
823 * disk, and re-reads it if not.
824 */
825
826 loose_iter = cache_ref_iterator_begin(get_loose_ref_cache(refs),
827 prefix, 1);
828
829 /*
830 * The packed-refs file might contain broken references, for
831 * example an old version of a reference that points at an
832 * object that has since been garbage-collected. This is OK as
833 * long as there is a corresponding loose reference that
834 * overrides it, and we don't want to emit an error message in
835 * this case. So ask the packed_ref_store for all of its
836 * references, and (if needed) do our own check for broken
837 * ones in files_ref_iterator_advance(), after we have merged
838 * the packed and loose references.
839 */
840 packed_iter = refs_ref_iterator_begin(
841 refs->packed_ref_store, prefix, 0,
842 DO_FOR_EACH_INCLUDE_BROKEN);
843
844 overlay_iter = overlay_ref_iterator_begin(loose_iter, packed_iter);
845
846 iter = xcalloc(1, sizeof(*iter));
847 ref_iterator = &iter->base;
848 base_ref_iterator_init(ref_iterator, &files_ref_iterator_vtable,
849 overlay_iter->ordered);
850 iter->iter0 = overlay_iter;
851 iter->flags = flags;
852
853 return ref_iterator;
854 }
855
856 /*
857 * Verify that the reference locked by lock has the value old_oid
858 * (unless it is NULL). Fail if the reference doesn't exist and
859 * mustexist is set. Return 0 on success. On error, write an error
860 * message to err, set errno, and return a negative value.
861 */
862 static int verify_lock(struct ref_store *ref_store, struct ref_lock *lock,
863 const struct object_id *old_oid, int mustexist,
864 struct strbuf *err)
865 {
866 assert(err);
867
868 if (refs_read_ref_full(ref_store, lock->ref_name,
869 mustexist ? RESOLVE_REF_READING : 0,
870 &lock->old_oid, NULL)) {
871 if (old_oid) {
872 int save_errno = errno;
873 strbuf_addf(err, "can't verify ref '%s'", lock->ref_name);
874 errno = save_errno;
875 return -1;
876 } else {
877 oidclr(&lock->old_oid);
878 return 0;
879 }
880 }
881 if (old_oid && !oideq(&lock->old_oid, old_oid)) {
882 strbuf_addf(err, "ref '%s' is at %s but expected %s",
883 lock->ref_name,
884 oid_to_hex(&lock->old_oid),
885 oid_to_hex(old_oid));
886 errno = EBUSY;
887 return -1;
888 }
889 return 0;
890 }
891
892 static int remove_empty_directories(struct strbuf *path)
893 {
894 /*
895 * we want to create a file but there is a directory there;
896 * if that is an empty directory (or a directory that contains
897 * only empty directories), remove them.
898 */
899 return remove_dir_recursively(path, REMOVE_DIR_EMPTY_ONLY);
900 }
901
902 static int create_reflock(const char *path, void *cb)
903 {
904 struct lock_file *lk = cb;
905
906 return hold_lock_file_for_update_timeout(
907 lk, path, LOCK_NO_DEREF,
908 get_files_ref_lock_timeout_ms()) < 0 ? -1 : 0;
909 }
910
911 /*
912 * Locks a ref returning the lock on success and NULL on failure.
913 * On failure errno is set to something meaningful.
914 */
915 static struct ref_lock *lock_ref_oid_basic(struct files_ref_store *refs,
916 const char *refname,
917 const struct object_id *old_oid,
918 const struct string_list *extras,
919 const struct string_list *skip,
920 unsigned int flags, int *type,
921 struct strbuf *err)
922 {
923 struct strbuf ref_file = STRBUF_INIT;
924 struct ref_lock *lock;
925 int last_errno = 0;
926 int mustexist = (old_oid && !is_null_oid(old_oid));
927 int resolve_flags = RESOLVE_REF_NO_RECURSE;
928 int resolved;
929
930 files_assert_main_repository(refs, "lock_ref_oid_basic");
931 assert(err);
932
933 lock = xcalloc(1, sizeof(struct ref_lock));
934
935 if (mustexist)
936 resolve_flags |= RESOLVE_REF_READING;
937 if (flags & REF_DELETING)
938 resolve_flags |= RESOLVE_REF_ALLOW_BAD_NAME;
939
940 files_ref_path(refs, &ref_file, refname);
941 resolved = !!refs_resolve_ref_unsafe(&refs->base,
942 refname, resolve_flags,
943 &lock->old_oid, type);
944 if (!resolved && errno == EISDIR) {
945 /*
946 * we are trying to lock foo but we used to
947 * have foo/bar which now does not exist;
948 * it is normal for the empty directory 'foo'
949 * to remain.
950 */
951 if (remove_empty_directories(&ref_file)) {
952 last_errno = errno;
953 if (!refs_verify_refname_available(
954 &refs->base,
955 refname, extras, skip, err))
956 strbuf_addf(err, "there are still refs under '%s'",
957 refname);
958 goto error_return;
959 }
960 resolved = !!refs_resolve_ref_unsafe(&refs->base,
961 refname, resolve_flags,
962 &lock->old_oid, type);
963 }
964 if (!resolved) {
965 last_errno = errno;
966 if (last_errno != ENOTDIR ||
967 !refs_verify_refname_available(&refs->base, refname,
968 extras, skip, err))
969 strbuf_addf(err, "unable to resolve reference '%s': %s",
970 refname, strerror(last_errno));
971
972 goto error_return;
973 }
974
975 /*
976 * If the ref did not exist and we are creating it, make sure
977 * there is no existing packed ref whose name begins with our
978 * refname, nor a packed ref whose name is a proper prefix of
979 * our refname.
980 */
981 if (is_null_oid(&lock->old_oid) &&
982 refs_verify_refname_available(refs->packed_ref_store, refname,
983 extras, skip, err)) {
984 last_errno = ENOTDIR;
985 goto error_return;
986 }
987
988 lock->ref_name = xstrdup(refname);
989
990 if (raceproof_create_file(ref_file.buf, create_reflock, &lock->lk)) {
991 last_errno = errno;
992 unable_to_lock_message(ref_file.buf, errno, err);
993 goto error_return;
994 }
995
996 if (verify_lock(&refs->base, lock, old_oid, mustexist, err)) {
997 last_errno = errno;
998 goto error_return;
999 }
1000 goto out;
1001
1002 error_return:
1003 unlock_ref(lock);
1004 lock = NULL;
1005
1006 out:
1007 strbuf_release(&ref_file);
1008 errno = last_errno;
1009 return lock;
1010 }
1011
1012 struct ref_to_prune {
1013 struct ref_to_prune *next;
1014 struct object_id oid;
1015 char name[FLEX_ARRAY];
1016 };
1017
1018 enum {
1019 REMOVE_EMPTY_PARENTS_REF = 0x01,
1020 REMOVE_EMPTY_PARENTS_REFLOG = 0x02
1021 };
1022
1023 /*
1024 * Remove empty parent directories associated with the specified
1025 * reference and/or its reflog, but spare [logs/]refs/ and immediate
1026 * subdirs. flags is a combination of REMOVE_EMPTY_PARENTS_REF and/or
1027 * REMOVE_EMPTY_PARENTS_REFLOG.
1028 */
1029 static void try_remove_empty_parents(struct files_ref_store *refs,
1030 const char *refname,
1031 unsigned int flags)
1032 {
1033 struct strbuf buf = STRBUF_INIT;
1034 struct strbuf sb = STRBUF_INIT;
1035 char *p, *q;
1036 int i;
1037
1038 strbuf_addstr(&buf, refname);
1039 p = buf.buf;
1040 for (i = 0; i < 2; i++) { /* refs/{heads,tags,...}/ */
1041 while (*p && *p != '/')
1042 p++;
1043 /* tolerate duplicate slashes; see check_refname_format() */
1044 while (*p == '/')
1045 p++;
1046 }
1047 q = buf.buf + buf.len;
1048 while (flags & (REMOVE_EMPTY_PARENTS_REF | REMOVE_EMPTY_PARENTS_REFLOG)) {
1049 while (q > p && *q != '/')
1050 q--;
1051 while (q > p && *(q-1) == '/')
1052 q--;
1053 if (q == p)
1054 break;
1055 strbuf_setlen(&buf, q - buf.buf);
1056
1057 strbuf_reset(&sb);
1058 files_ref_path(refs, &sb, buf.buf);
1059 if ((flags & REMOVE_EMPTY_PARENTS_REF) && rmdir(sb.buf))
1060 flags &= ~REMOVE_EMPTY_PARENTS_REF;
1061
1062 strbuf_reset(&sb);
1063 files_reflog_path(refs, &sb, buf.buf);
1064 if ((flags & REMOVE_EMPTY_PARENTS_REFLOG) && rmdir(sb.buf))
1065 flags &= ~REMOVE_EMPTY_PARENTS_REFLOG;
1066 }
1067 strbuf_release(&buf);
1068 strbuf_release(&sb);
1069 }
1070
1071 /* make sure nobody touched the ref, and unlink */
1072 static void prune_ref(struct files_ref_store *refs, struct ref_to_prune *r)
1073 {
1074 struct ref_transaction *transaction;
1075 struct strbuf err = STRBUF_INIT;
1076 int ret = -1;
1077
1078 if (check_refname_format(r->name, 0))
1079 return;
1080
1081 transaction = ref_store_transaction_begin(&refs->base, &err);
1082 if (!transaction)
1083 goto cleanup;
1084 ref_transaction_add_update(
1085 transaction, r->name,
1086 REF_NO_DEREF | REF_HAVE_NEW | REF_HAVE_OLD | REF_IS_PRUNING,
1087 &null_oid, &r->oid, NULL);
1088 if (ref_transaction_commit(transaction, &err))
1089 goto cleanup;
1090
1091 ret = 0;
1092
1093 cleanup:
1094 if (ret)
1095 error("%s", err.buf);
1096 strbuf_release(&err);
1097 ref_transaction_free(transaction);
1098 return;
1099 }
1100
1101 /*
1102 * Prune the loose versions of the references in the linked list
1103 * `*refs_to_prune`, freeing the entries in the list as we go.
1104 */
1105 static void prune_refs(struct files_ref_store *refs, struct ref_to_prune **refs_to_prune)
1106 {
1107 while (*refs_to_prune) {
1108 struct ref_to_prune *r = *refs_to_prune;
1109 *refs_to_prune = r->next;
1110 prune_ref(refs, r);
1111 free(r);
1112 }
1113 }
1114
1115 /*
1116 * Return true if the specified reference should be packed.
1117 */
1118 static int should_pack_ref(const char *refname,
1119 const struct object_id *oid, unsigned int ref_flags,
1120 unsigned int pack_flags)
1121 {
1122 /* Do not pack per-worktree refs: */
1123 if (ref_type(refname) != REF_TYPE_NORMAL)
1124 return 0;
1125
1126 /* Do not pack non-tags unless PACK_REFS_ALL is set: */
1127 if (!(pack_flags & PACK_REFS_ALL) && !starts_with(refname, "refs/tags/"))
1128 return 0;
1129
1130 /* Do not pack symbolic refs: */
1131 if (ref_flags & REF_ISSYMREF)
1132 return 0;
1133
1134 /* Do not pack broken refs: */
1135 if (!ref_resolves_to_object(refname, oid, ref_flags))
1136 return 0;
1137
1138 return 1;
1139 }
1140
1141 static int files_pack_refs(struct ref_store *ref_store, unsigned int flags)
1142 {
1143 struct files_ref_store *refs =
1144 files_downcast(ref_store, REF_STORE_WRITE | REF_STORE_ODB,
1145 "pack_refs");
1146 struct ref_iterator *iter;
1147 int ok;
1148 struct ref_to_prune *refs_to_prune = NULL;
1149 struct strbuf err = STRBUF_INIT;
1150 struct ref_transaction *transaction;
1151
1152 transaction = ref_store_transaction_begin(refs->packed_ref_store, &err);
1153 if (!transaction)
1154 return -1;
1155
1156 packed_refs_lock(refs->packed_ref_store, LOCK_DIE_ON_ERROR, &err);
1157
1158 iter = cache_ref_iterator_begin(get_loose_ref_cache(refs), NULL, 0);
1159 while ((ok = ref_iterator_advance(iter)) == ITER_OK) {
1160 /*
1161 * If the loose reference can be packed, add an entry
1162 * in the packed ref cache. If the reference should be
1163 * pruned, also add it to refs_to_prune.
1164 */
1165 if (!should_pack_ref(iter->refname, iter->oid, iter->flags,
1166 flags))
1167 continue;
1168
1169 /*
1170 * Add a reference creation for this reference to the
1171 * packed-refs transaction:
1172 */
1173 if (ref_transaction_update(transaction, iter->refname,
1174 iter->oid, NULL,
1175 REF_NO_DEREF, NULL, &err))
1176 die("failure preparing to create packed reference %s: %s",
1177 iter->refname, err.buf);
1178
1179 /* Schedule the loose reference for pruning if requested. */
1180 if ((flags & PACK_REFS_PRUNE)) {
1181 struct ref_to_prune *n;
1182 FLEX_ALLOC_STR(n, name, iter->refname);
1183 oidcpy(&n->oid, iter->oid);
1184 n->next = refs_to_prune;
1185 refs_to_prune = n;
1186 }
1187 }
1188 if (ok != ITER_DONE)
1189 die("error while iterating over references");
1190
1191 if (ref_transaction_commit(transaction, &err))
1192 die("unable to write new packed-refs: %s", err.buf);
1193
1194 ref_transaction_free(transaction);
1195
1196 packed_refs_unlock(refs->packed_ref_store);
1197
1198 prune_refs(refs, &refs_to_prune);
1199 strbuf_release(&err);
1200 return 0;
1201 }
1202
1203 static int files_delete_refs(struct ref_store *ref_store, const char *msg,
1204 struct string_list *refnames, unsigned int flags)
1205 {
1206 struct files_ref_store *refs =
1207 files_downcast(ref_store, REF_STORE_WRITE, "delete_refs");
1208 struct strbuf err = STRBUF_INIT;
1209 int i, result = 0;
1210
1211 if (!refnames->nr)
1212 return 0;
1213
1214 if (packed_refs_lock(refs->packed_ref_store, 0, &err))
1215 goto error;
1216
1217 if (refs_delete_refs(refs->packed_ref_store, msg, refnames, flags)) {
1218 packed_refs_unlock(refs->packed_ref_store);
1219 goto error;
1220 }
1221
1222 packed_refs_unlock(refs->packed_ref_store);
1223
1224 for (i = 0; i < refnames->nr; i++) {
1225 const char *refname = refnames->items[i].string;
1226
1227 if (refs_delete_ref(&refs->base, msg, refname, NULL, flags))
1228 result |= error(_("could not remove reference %s"), refname);
1229 }
1230
1231 strbuf_release(&err);
1232 return result;
1233
1234 error:
1235 /*
1236 * If we failed to rewrite the packed-refs file, then it is
1237 * unsafe to try to remove loose refs, because doing so might
1238 * expose an obsolete packed value for a reference that might
1239 * even point at an object that has been garbage collected.
1240 */
1241 if (refnames->nr == 1)
1242 error(_("could not delete reference %s: %s"),
1243 refnames->items[0].string, err.buf);
1244 else
1245 error(_("could not delete references: %s"), err.buf);
1246
1247 strbuf_release(&err);
1248 return -1;
1249 }
1250
1251 /*
1252 * People using contrib's git-new-workdir have .git/logs/refs ->
1253 * /some/other/path/.git/logs/refs, and that may live on another device.
1254 *
1255 * IOW, to avoid cross device rename errors, the temporary renamed log must
1256 * live into logs/refs.
1257 */
1258 #define TMP_RENAMED_LOG "refs/.tmp-renamed-log"
1259
1260 struct rename_cb {
1261 const char *tmp_renamed_log;
1262 int true_errno;
1263 };
1264
1265 static int rename_tmp_log_callback(const char *path, void *cb_data)
1266 {
1267 struct rename_cb *cb = cb_data;
1268
1269 if (rename(cb->tmp_renamed_log, path)) {
1270 /*
1271 * rename(a, b) when b is an existing directory ought
1272 * to result in ISDIR, but Solaris 5.8 gives ENOTDIR.
1273 * Sheesh. Record the true errno for error reporting,
1274 * but report EISDIR to raceproof_create_file() so
1275 * that it knows to retry.
1276 */
1277 cb->true_errno = errno;
1278 if (errno == ENOTDIR)
1279 errno = EISDIR;
1280 return -1;
1281 } else {
1282 return 0;
1283 }
1284 }
1285
1286 static int rename_tmp_log(struct files_ref_store *refs, const char *newrefname)
1287 {
1288 struct strbuf path = STRBUF_INIT;
1289 struct strbuf tmp = STRBUF_INIT;
1290 struct rename_cb cb;
1291 int ret;
1292
1293 files_reflog_path(refs, &path, newrefname);
1294 files_reflog_path(refs, &tmp, TMP_RENAMED_LOG);
1295 cb.tmp_renamed_log = tmp.buf;
1296 ret = raceproof_create_file(path.buf, rename_tmp_log_callback, &cb);
1297 if (ret) {
1298 if (errno == EISDIR)
1299 error("directory not empty: %s", path.buf);
1300 else
1301 error("unable to move logfile %s to %s: %s",
1302 tmp.buf, path.buf,
1303 strerror(cb.true_errno));
1304 }
1305
1306 strbuf_release(&path);
1307 strbuf_release(&tmp);
1308 return ret;
1309 }
1310
1311 static int write_ref_to_lockfile(struct ref_lock *lock,
1312 const struct object_id *oid, struct strbuf *err);
1313 static int commit_ref_update(struct files_ref_store *refs,
1314 struct ref_lock *lock,
1315 const struct object_id *oid, const char *logmsg,
1316 struct strbuf *err);
1317
1318 static int files_copy_or_rename_ref(struct ref_store *ref_store,
1319 const char *oldrefname, const char *newrefname,
1320 const char *logmsg, int copy)
1321 {
1322 struct files_ref_store *refs =
1323 files_downcast(ref_store, REF_STORE_WRITE, "rename_ref");
1324 struct object_id oid, orig_oid;
1325 int flag = 0, logmoved = 0;
1326 struct ref_lock *lock;
1327 struct stat loginfo;
1328 struct strbuf sb_oldref = STRBUF_INIT;
1329 struct strbuf sb_newref = STRBUF_INIT;
1330 struct strbuf tmp_renamed_log = STRBUF_INIT;
1331 int log, ret;
1332 struct strbuf err = STRBUF_INIT;
1333
1334 files_reflog_path(refs, &sb_oldref, oldrefname);
1335 files_reflog_path(refs, &sb_newref, newrefname);
1336 files_reflog_path(refs, &tmp_renamed_log, TMP_RENAMED_LOG);
1337
1338 log = !lstat(sb_oldref.buf, &loginfo);
1339 if (log && S_ISLNK(loginfo.st_mode)) {
1340 ret = error("reflog for %s is a symlink", oldrefname);
1341 goto out;
1342 }
1343
1344 if (!refs_resolve_ref_unsafe(&refs->base, oldrefname,
1345 RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
1346 &orig_oid, &flag)) {
1347 ret = error("refname %s not found", oldrefname);
1348 goto out;
1349 }
1350
1351 if (flag & REF_ISSYMREF) {
1352 if (copy)
1353 ret = error("refname %s is a symbolic ref, copying it is not supported",
1354 oldrefname);
1355 else
1356 ret = error("refname %s is a symbolic ref, renaming it is not supported",
1357 oldrefname);
1358 goto out;
1359 }
1360 if (!refs_rename_ref_available(&refs->base, oldrefname, newrefname)) {
1361 ret = 1;
1362 goto out;
1363 }
1364
1365 if (!copy && log && rename(sb_oldref.buf, tmp_renamed_log.buf)) {
1366 ret = error("unable to move logfile logs/%s to logs/"TMP_RENAMED_LOG": %s",
1367 oldrefname, strerror(errno));
1368 goto out;
1369 }
1370
1371 if (copy && log && copy_file(tmp_renamed_log.buf, sb_oldref.buf, 0644)) {
1372 ret = error("unable to copy logfile logs/%s to logs/"TMP_RENAMED_LOG": %s",
1373 oldrefname, strerror(errno));
1374 goto out;
1375 }
1376
1377 if (!copy && refs_delete_ref(&refs->base, logmsg, oldrefname,
1378 &orig_oid, REF_NO_DEREF)) {
1379 error("unable to delete old %s", oldrefname);
1380 goto rollback;
1381 }
1382
1383 /*
1384 * Since we are doing a shallow lookup, oid is not the
1385 * correct value to pass to delete_ref as old_oid. But that
1386 * doesn't matter, because an old_oid check wouldn't add to
1387 * the safety anyway; we want to delete the reference whatever
1388 * its current value.
1389 */
1390 if (!copy && !refs_read_ref_full(&refs->base, newrefname,
1391 RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
1392 &oid, NULL) &&
1393 refs_delete_ref(&refs->base, NULL, newrefname,
1394 NULL, REF_NO_DEREF)) {
1395 if (errno == EISDIR) {
1396 struct strbuf path = STRBUF_INIT;
1397 int result;
1398
1399 files_ref_path(refs, &path, newrefname);
1400 result = remove_empty_directories(&path);
1401 strbuf_release(&path);
1402
1403 if (result) {
1404 error("Directory not empty: %s", newrefname);
1405 goto rollback;
1406 }
1407 } else {
1408 error("unable to delete existing %s", newrefname);
1409 goto rollback;
1410 }
1411 }
1412
1413 if (log && rename_tmp_log(refs, newrefname))
1414 goto rollback;
1415
1416 logmoved = log;
1417
1418 lock = lock_ref_oid_basic(refs, newrefname, NULL, NULL, NULL,
1419 REF_NO_DEREF, NULL, &err);
1420 if (!lock) {
1421 if (copy)
1422 error("unable to copy '%s' to '%s': %s", oldrefname, newrefname, err.buf);
1423 else
1424 error("unable to rename '%s' to '%s': %s", oldrefname, newrefname, err.buf);
1425 strbuf_release(&err);
1426 goto rollback;
1427 }
1428 oidcpy(&lock->old_oid, &orig_oid);
1429
1430 if (write_ref_to_lockfile(lock, &orig_oid, &err) ||
1431 commit_ref_update(refs, lock, &orig_oid, logmsg, &err)) {
1432 error("unable to write current sha1 into %s: %s", newrefname, err.buf);
1433 strbuf_release(&err);
1434 goto rollback;
1435 }
1436
1437 ret = 0;
1438 goto out;
1439
1440 rollback:
1441 lock = lock_ref_oid_basic(refs, oldrefname, NULL, NULL, NULL,
1442 REF_NO_DEREF, NULL, &err);
1443 if (!lock) {
1444 error("unable to lock %s for rollback: %s", oldrefname, err.buf);
1445 strbuf_release(&err);
1446 goto rollbacklog;
1447 }
1448
1449 flag = log_all_ref_updates;
1450 log_all_ref_updates = LOG_REFS_NONE;
1451 if (write_ref_to_lockfile(lock, &orig_oid, &err) ||
1452 commit_ref_update(refs, lock, &orig_oid, NULL, &err)) {
1453 error("unable to write current sha1 into %s: %s", oldrefname, err.buf);
1454 strbuf_release(&err);
1455 }
1456 log_all_ref_updates = flag;
1457
1458 rollbacklog:
1459 if (logmoved && rename(sb_newref.buf, sb_oldref.buf))
1460 error("unable to restore logfile %s from %s: %s",
1461 oldrefname, newrefname, strerror(errno));
1462 if (!logmoved && log &&
1463 rename(tmp_renamed_log.buf, sb_oldref.buf))
1464 error("unable to restore logfile %s from logs/"TMP_RENAMED_LOG": %s",
1465 oldrefname, strerror(errno));
1466 ret = 1;
1467 out:
1468 strbuf_release(&sb_newref);
1469 strbuf_release(&sb_oldref);
1470 strbuf_release(&tmp_renamed_log);
1471
1472 return ret;
1473 }
1474
1475 static int files_rename_ref(struct ref_store *ref_store,
1476 const char *oldrefname, const char *newrefname,
1477 const char *logmsg)
1478 {
1479 return files_copy_or_rename_ref(ref_store, oldrefname,
1480 newrefname, logmsg, 0);
1481 }
1482
1483 static int files_copy_ref(struct ref_store *ref_store,
1484 const char *oldrefname, const char *newrefname,
1485 const char *logmsg)
1486 {
1487 return files_copy_or_rename_ref(ref_store, oldrefname,
1488 newrefname, logmsg, 1);
1489 }
1490
1491 static int close_ref_gently(struct ref_lock *lock)
1492 {
1493 if (close_lock_file_gently(&lock->lk))
1494 return -1;
1495 return 0;
1496 }
1497
1498 static int commit_ref(struct ref_lock *lock)
1499 {
1500 char *path = get_locked_file_path(&lock->lk);
1501 struct stat st;
1502
1503 if (!lstat(path, &st) && S_ISDIR(st.st_mode)) {
1504 /*
1505 * There is a directory at the path we want to rename
1506 * the lockfile to. Hopefully it is empty; try to
1507 * delete it.
1508 */
1509 size_t len = strlen(path);
1510 struct strbuf sb_path = STRBUF_INIT;
1511
1512 strbuf_attach(&sb_path, path, len, len);
1513
1514 /*
1515 * If this fails, commit_lock_file() will also fail
1516 * and will report the problem.
1517 */
1518 remove_empty_directories(&sb_path);
1519 strbuf_release(&sb_path);
1520 } else {
1521 free(path);
1522 }
1523
1524 if (commit_lock_file(&lock->lk))
1525 return -1;
1526 return 0;
1527 }
1528
1529 static int open_or_create_logfile(const char *path, void *cb)
1530 {
1531 int *fd = cb;
1532
1533 *fd = open(path, O_APPEND | O_WRONLY | O_CREAT, 0666);
1534 return (*fd < 0) ? -1 : 0;
1535 }
1536
1537 /*
1538 * Create a reflog for a ref. If force_create = 0, only create the
1539 * reflog for certain refs (those for which should_autocreate_reflog
1540 * returns non-zero). Otherwise, create it regardless of the reference
1541 * name. If the logfile already existed or was created, return 0 and
1542 * set *logfd to the file descriptor opened for appending to the file.
1543 * If no logfile exists and we decided not to create one, return 0 and
1544 * set *logfd to -1. On failure, fill in *err, set *logfd to -1, and
1545 * return -1.
1546 */
1547 static int log_ref_setup(struct files_ref_store *refs,
1548 const char *refname, int force_create,
1549 int *logfd, struct strbuf *err)
1550 {
1551 struct strbuf logfile_sb = STRBUF_INIT;
1552 char *logfile;
1553
1554 files_reflog_path(refs, &logfile_sb, refname);
1555 logfile = strbuf_detach(&logfile_sb, NULL);
1556
1557 if (force_create || should_autocreate_reflog(refname)) {
1558 if (raceproof_create_file(logfile, open_or_create_logfile, logfd)) {
1559 if (errno == ENOENT)
1560 strbuf_addf(err, "unable to create directory for '%s': "
1561 "%s", logfile, strerror(errno));
1562 else if (errno == EISDIR)
1563 strbuf_addf(err, "there are still logs under '%s'",
1564 logfile);
1565 else
1566 strbuf_addf(err, "unable to append to '%s': %s",
1567 logfile, strerror(errno));
1568
1569 goto error;
1570 }
1571 } else {
1572 *logfd = open(logfile, O_APPEND | O_WRONLY, 0666);
1573 if (*logfd < 0) {
1574 if (errno == ENOENT || errno == EISDIR) {
1575 /*
1576 * The logfile doesn't already exist,
1577 * but that is not an error; it only
1578 * means that we won't write log
1579 * entries to it.
1580 */
1581 ;
1582 } else {
1583 strbuf_addf(err, "unable to append to '%s': %s",
1584 logfile, strerror(errno));
1585 goto error;
1586 }
1587 }
1588 }
1589
1590 if (*logfd >= 0)
1591 adjust_shared_perm(logfile);
1592
1593 free(logfile);
1594 return 0;
1595
1596 error:
1597 free(logfile);
1598 return -1;
1599 }
1600
1601 static int files_create_reflog(struct ref_store *ref_store,
1602 const char *refname, int force_create,
1603 struct strbuf *err)
1604 {
1605 struct files_ref_store *refs =
1606 files_downcast(ref_store, REF_STORE_WRITE, "create_reflog");
1607 int fd;
1608
1609 if (log_ref_setup(refs, refname, force_create, &fd, err))
1610 return -1;
1611
1612 if (fd >= 0)
1613 close(fd);
1614
1615 return 0;
1616 }
1617
1618 static int log_ref_write_fd(int fd, const struct object_id *old_oid,
1619 const struct object_id *new_oid,
1620 const char *committer, const char *msg)
1621 {
1622 struct strbuf sb = STRBUF_INIT;
1623 int ret = 0;
1624
1625 strbuf_addf(&sb, "%s %s %s", oid_to_hex(old_oid), oid_to_hex(new_oid), committer);
1626 if (msg && *msg)
1627 copy_reflog_msg(&sb, msg);
1628 strbuf_addch(&sb, '\n');
1629 if (write_in_full(fd, sb.buf, sb.len) < 0)
1630 ret = -1;
1631 strbuf_release(&sb);
1632 return ret;
1633 }
1634
1635 static int files_log_ref_write(struct files_ref_store *refs,
1636 const char *refname, const struct object_id *old_oid,
1637 const struct object_id *new_oid, const char *msg,
1638 int flags, struct strbuf *err)
1639 {
1640 int logfd, result;
1641
1642 if (log_all_ref_updates == LOG_REFS_UNSET)
1643 log_all_ref_updates = is_bare_repository() ? LOG_REFS_NONE : LOG_REFS_NORMAL;
1644
1645 result = log_ref_setup(refs, refname,
1646 flags & REF_FORCE_CREATE_REFLOG,
1647 &logfd, err);
1648
1649 if (result)
1650 return result;
1651
1652 if (logfd < 0)
1653 return 0;
1654 result = log_ref_write_fd(logfd, old_oid, new_oid,
1655 git_committer_info(0), msg);
1656 if (result) {
1657 struct strbuf sb = STRBUF_INIT;
1658 int save_errno = errno;
1659
1660 files_reflog_path(refs, &sb, refname);
1661 strbuf_addf(err, "unable to append to '%s': %s",
1662 sb.buf, strerror(save_errno));
1663 strbuf_release(&sb);
1664 close(logfd);
1665 return -1;
1666 }
1667 if (close(logfd)) {
1668 struct strbuf sb = STRBUF_INIT;
1669 int save_errno = errno;
1670
1671 files_reflog_path(refs, &sb, refname);
1672 strbuf_addf(err, "unable to append to '%s': %s",
1673 sb.buf, strerror(save_errno));
1674 strbuf_release(&sb);
1675 return -1;
1676 }
1677 return 0;
1678 }
1679
1680 /*
1681 * Write oid into the open lockfile, then close the lockfile. On
1682 * errors, rollback the lockfile, fill in *err and return -1.
1683 */
1684 static int write_ref_to_lockfile(struct ref_lock *lock,
1685 const struct object_id *oid, struct strbuf *err)
1686 {
1687 static char term = '\n';
1688 struct object *o;
1689 int fd;
1690
1691 o = parse_object(the_repository, oid);
1692 if (!o) {
1693 strbuf_addf(err,
1694 "trying to write ref '%s' with nonexistent object %s",
1695 lock->ref_name, oid_to_hex(oid));
1696 unlock_ref(lock);
1697 return -1;
1698 }
1699 if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
1700 strbuf_addf(err,
1701 "trying to write non-commit object %s to branch '%s'",
1702 oid_to_hex(oid), lock->ref_name);
1703 unlock_ref(lock);
1704 return -1;
1705 }
1706 fd = get_lock_file_fd(&lock->lk);
1707 if (write_in_full(fd, oid_to_hex(oid), the_hash_algo->hexsz) < 0 ||
1708 write_in_full(fd, &term, 1) < 0 ||
1709 close_ref_gently(lock) < 0) {
1710 strbuf_addf(err,
1711 "couldn't write '%s'", get_lock_file_path(&lock->lk));
1712 unlock_ref(lock);
1713 return -1;
1714 }
1715 return 0;
1716 }
1717
1718 /*
1719 * Commit a change to a loose reference that has already been written
1720 * to the loose reference lockfile. Also update the reflogs if
1721 * necessary, using the specified lockmsg (which can be NULL).
1722 */
1723 static int commit_ref_update(struct files_ref_store *refs,
1724 struct ref_lock *lock,
1725 const struct object_id *oid, const char *logmsg,
1726 struct strbuf *err)
1727 {
1728 files_assert_main_repository(refs, "commit_ref_update");
1729
1730 clear_loose_ref_cache(refs);
1731 if (files_log_ref_write(refs, lock->ref_name,
1732 &lock->old_oid, oid,
1733 logmsg, 0, err)) {
1734 char *old_msg = strbuf_detach(err, NULL);
1735 strbuf_addf(err, "cannot update the ref '%s': %s",
1736 lock->ref_name, old_msg);
1737 free(old_msg);
1738 unlock_ref(lock);
1739 return -1;
1740 }
1741
1742 if (strcmp(lock->ref_name, "HEAD") != 0) {
1743 /*
1744 * Special hack: If a branch is updated directly and HEAD
1745 * points to it (may happen on the remote side of a push
1746 * for example) then logically the HEAD reflog should be
1747 * updated too.
1748 * A generic solution implies reverse symref information,
1749 * but finding all symrefs pointing to the given branch
1750 * would be rather costly for this rare event (the direct
1751 * update of a branch) to be worth it. So let's cheat and
1752 * check with HEAD only which should cover 99% of all usage
1753 * scenarios (even 100% of the default ones).
1754 */
1755 int head_flag;
1756 const char *head_ref;
1757
1758 head_ref = refs_resolve_ref_unsafe(&refs->base, "HEAD",
1759 RESOLVE_REF_READING,
1760 NULL, &head_flag);
1761 if (head_ref && (head_flag & REF_ISSYMREF) &&
1762 !strcmp(head_ref, lock->ref_name)) {
1763 struct strbuf log_err = STRBUF_INIT;
1764 if (files_log_ref_write(refs, "HEAD",
1765 &lock->old_oid, oid,
1766 logmsg, 0, &log_err)) {
1767 error("%s", log_err.buf);
1768 strbuf_release(&log_err);
1769 }
1770 }
1771 }
1772
1773 if (commit_ref(lock)) {
1774 strbuf_addf(err, "couldn't set '%s'", lock->ref_name);
1775 unlock_ref(lock);
1776 return -1;
1777 }
1778
1779 unlock_ref(lock);
1780 return 0;
1781 }
1782
1783 static int create_ref_symlink(struct ref_lock *lock, const char *target)
1784 {
1785 int ret = -1;
1786 #ifndef NO_SYMLINK_HEAD
1787 char *ref_path = get_locked_file_path(&lock->lk);
1788 unlink(ref_path);
1789 ret = symlink(target, ref_path);
1790 free(ref_path);
1791
1792 if (ret)
1793 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
1794 #endif
1795 return ret;
1796 }
1797
1798 static void update_symref_reflog(struct files_ref_store *refs,
1799 struct ref_lock *lock, const char *refname,
1800 const char *target, const char *logmsg)
1801 {
1802 struct strbuf err = STRBUF_INIT;
1803 struct object_id new_oid;
1804 if (logmsg &&
1805 !refs_read_ref_full(&refs->base, target,
1806 RESOLVE_REF_READING, &new_oid, NULL) &&
1807 files_log_ref_write(refs, refname, &lock->old_oid,
1808 &new_oid, logmsg, 0, &err)) {
1809 error("%s", err.buf);
1810 strbuf_release(&err);
1811 }
1812 }
1813
1814 static int create_symref_locked(struct files_ref_store *refs,
1815 struct ref_lock *lock, const char *refname,
1816 const char *target, const char *logmsg)
1817 {
1818 if (prefer_symlink_refs && !create_ref_symlink(lock, target)) {
1819 update_symref_reflog(refs, lock, refname, target, logmsg);
1820 return 0;
1821 }
1822
1823 if (!fdopen_lock_file(&lock->lk, "w"))
1824 return error("unable to fdopen %s: %s",
1825 lock->lk.tempfile->filename.buf, strerror(errno));
1826
1827 update_symref_reflog(refs, lock, refname, target, logmsg);
1828
1829 /* no error check; commit_ref will check ferror */
1830 fprintf(lock->lk.tempfile->fp, "ref: %s\n", target);
1831 if (commit_ref(lock) < 0)
1832 return error("unable to write symref for %s: %s", refname,
1833 strerror(errno));
1834 return 0;
1835 }
1836
1837 static int files_create_symref(struct ref_store *ref_store,
1838 const char *refname, const char *target,
1839 const char *logmsg)
1840 {
1841 struct files_ref_store *refs =
1842 files_downcast(ref_store, REF_STORE_WRITE, "create_symref");
1843 struct strbuf err = STRBUF_INIT;
1844 struct ref_lock *lock;
1845 int ret;
1846
1847 lock = lock_ref_oid_basic(refs, refname, NULL,
1848 NULL, NULL, REF_NO_DEREF, NULL,
1849 &err);
1850 if (!lock) {
1851 error("%s", err.buf);
1852 strbuf_release(&err);
1853 return -1;
1854 }
1855
1856 ret = create_symref_locked(refs, lock, refname, target, logmsg);
1857 unlock_ref(lock);
1858 return ret;
1859 }
1860
1861 static int files_reflog_exists(struct ref_store *ref_store,
1862 const char *refname)
1863 {
1864 struct files_ref_store *refs =
1865 files_downcast(ref_store, REF_STORE_READ, "reflog_exists");
1866 struct strbuf sb = STRBUF_INIT;
1867 struct stat st;
1868 int ret;
1869
1870 files_reflog_path(refs, &sb, refname);
1871 ret = !lstat(sb.buf, &st) && S_ISREG(st.st_mode);
1872 strbuf_release(&sb);
1873 return ret;
1874 }
1875
1876 static int files_delete_reflog(struct ref_store *ref_store,
1877 const char *refname)
1878 {
1879 struct files_ref_store *refs =
1880 files_downcast(ref_store, REF_STORE_WRITE, "delete_reflog");
1881 struct strbuf sb = STRBUF_INIT;
1882 int ret;
1883
1884 files_reflog_path(refs, &sb, refname);
1885 ret = remove_path(sb.buf);
1886 strbuf_release(&sb);
1887 return ret;
1888 }
1889
1890 static int show_one_reflog_ent(struct strbuf *sb, each_reflog_ent_fn fn, void *cb_data)
1891 {
1892 struct object_id ooid, noid;
1893 char *email_end, *message;
1894 timestamp_t timestamp;
1895 int tz;
1896 const char *p = sb->buf;
1897
1898 /* old SP new SP name <email> SP time TAB msg LF */
1899 if (!sb->len || sb->buf[sb->len - 1] != '\n' ||
1900 parse_oid_hex(p, &ooid, &p) || *p++ != ' ' ||
1901 parse_oid_hex(p, &noid, &p) || *p++ != ' ' ||
1902 !(email_end = strchr(p, '>')) ||
1903 email_end[1] != ' ' ||
1904 !(timestamp = parse_timestamp(email_end + 2, &message, 10)) ||
1905 !message || message[0] != ' ' ||
1906 (message[1] != '+' && message[1] != '-') ||
1907 !isdigit(message[2]) || !isdigit(message[3]) ||
1908 !isdigit(message[4]) || !isdigit(message[5]))
1909 return 0; /* corrupt? */
1910 email_end[1] = '\0';
1911 tz = strtol(message + 1, NULL, 10);
1912 if (message[6] != '\t')
1913 message += 6;
1914 else
1915 message += 7;
1916 return fn(&ooid, &noid, p, timestamp, tz, message, cb_data);
1917 }
1918
1919 static char *find_beginning_of_line(char *bob, char *scan)
1920 {
1921 while (bob < scan && *(--scan) != '\n')
1922 ; /* keep scanning backwards */
1923 /*
1924 * Return either beginning of the buffer, or LF at the end of
1925 * the previous line.
1926 */
1927 return scan;
1928 }
1929
1930 static int files_for_each_reflog_ent_reverse(struct ref_store *ref_store,
1931 const char *refname,
1932 each_reflog_ent_fn fn,
1933 void *cb_data)
1934 {
1935 struct files_ref_store *refs =
1936 files_downcast(ref_store, REF_STORE_READ,
1937 "for_each_reflog_ent_reverse");
1938 struct strbuf sb = STRBUF_INIT;
1939 FILE *logfp;
1940 long pos;
1941 int ret = 0, at_tail = 1;
1942
1943 files_reflog_path(refs, &sb, refname);
1944 logfp = fopen(sb.buf, "r");
1945 strbuf_release(&sb);
1946 if (!logfp)
1947 return -1;
1948
1949 /* Jump to the end */
1950 if (fseek(logfp, 0, SEEK_END) < 0)
1951 ret = error("cannot seek back reflog for %s: %s",
1952 refname, strerror(errno));
1953 pos = ftell(logfp);
1954 while (!ret && 0 < pos) {
1955 int cnt;
1956 size_t nread;
1957 char buf[BUFSIZ];
1958 char *endp, *scanp;
1959
1960 /* Fill next block from the end */
1961 cnt = (sizeof(buf) < pos) ? sizeof(buf) : pos;
1962 if (fseek(logfp, pos - cnt, SEEK_SET)) {
1963 ret = error("cannot seek back reflog for %s: %s",
1964 refname, strerror(errno));
1965 break;
1966 }
1967 nread = fread(buf, cnt, 1, logfp);
1968 if (nread != 1) {
1969 ret = error("cannot read %d bytes from reflog for %s: %s",
1970 cnt, refname, strerror(errno));
1971 break;
1972 }
1973 pos -= cnt;
1974
1975 scanp = endp = buf + cnt;
1976 if (at_tail && scanp[-1] == '\n')
1977 /* Looking at the final LF at the end of the file */
1978 scanp--;
1979 at_tail = 0;
1980
1981 while (buf < scanp) {
1982 /*
1983 * terminating LF of the previous line, or the beginning
1984 * of the buffer.
1985 */
1986 char *bp;
1987
1988 bp = find_beginning_of_line(buf, scanp);
1989
1990 if (*bp == '\n') {
1991 /*
1992 * The newline is the end of the previous line,
1993 * so we know we have complete line starting
1994 * at (bp + 1). Prefix it onto any prior data
1995 * we collected for the line and process it.
1996 */
1997 strbuf_splice(&sb, 0, 0, bp + 1, endp - (bp + 1));
1998 scanp = bp;
1999 endp = bp + 1;
2000 ret = show_one_reflog_ent(&sb, fn, cb_data);
2001 strbuf_reset(&sb);
2002 if (ret)
2003 break;
2004 } else if (!pos) {
2005 /*
2006 * We are at the start of the buffer, and the
2007 * start of the file; there is no previous
2008 * line, and we have everything for this one.
2009 * Process it, and we can end the loop.
2010 */
2011 strbuf_splice(&sb, 0, 0, buf, endp - buf);
2012 ret = show_one_reflog_ent(&sb, fn, cb_data);
2013 strbuf_reset(&sb);
2014 break;
2015 }
2016
2017 if (bp == buf) {
2018 /*
2019 * We are at the start of the buffer, and there
2020 * is more file to read backwards. Which means
2021 * we are in the middle of a line. Note that we
2022 * may get here even if *bp was a newline; that
2023 * just means we are at the exact end of the
2024 * previous line, rather than some spot in the
2025 * middle.
2026 *
2027 * Save away what we have to be combined with
2028 * the data from the next read.
2029 */
2030 strbuf_splice(&sb, 0, 0, buf, endp - buf);
2031 break;
2032 }
2033 }
2034
2035 }
2036 if (!ret && sb.len)
2037 BUG("reverse reflog parser had leftover data");
2038
2039 fclose(logfp);
2040 strbuf_release(&sb);
2041 return ret;
2042 }
2043
2044 static int files_for_each_reflog_ent(struct ref_store *ref_store,
2045 const char *refname,
2046 each_reflog_ent_fn fn, void *cb_data)
2047 {
2048 struct files_ref_store *refs =
2049 files_downcast(ref_store, REF_STORE_READ,
2050 "for_each_reflog_ent");
2051 FILE *logfp;
2052 struct strbuf sb = STRBUF_INIT;
2053 int ret = 0;
2054
2055 files_reflog_path(refs, &sb, refname);
2056 logfp = fopen(sb.buf, "r");
2057 strbuf_release(&sb);
2058 if (!logfp)
2059 return -1;
2060
2061 while (!ret && !strbuf_getwholeline(&sb, logfp, '\n'))
2062 ret = show_one_reflog_ent(&sb, fn, cb_data);
2063 fclose(logfp);
2064 strbuf_release(&sb);
2065 return ret;
2066 }
2067
2068 struct files_reflog_iterator {
2069 struct ref_iterator base;
2070
2071 struct ref_store *ref_store;
2072 struct dir_iterator *dir_iterator;
2073 struct object_id oid;
2074 };
2075
2076 static int files_reflog_iterator_advance(struct ref_iterator *ref_iterator)
2077 {
2078 struct files_reflog_iterator *iter =
2079 (struct files_reflog_iterator *)ref_iterator;
2080 struct dir_iterator *diter = iter->dir_iterator;
2081 int ok;
2082
2083 while ((ok = dir_iterator_advance(diter)) == ITER_OK) {
2084 int flags;
2085
2086 if (!S_ISREG(diter->st.st_mode))
2087 continue;
2088 if (diter->basename[0] == '.')
2089 continue;
2090 if (ends_with(diter->basename, ".lock"))
2091 continue;
2092
2093 if (refs_read_ref_full(iter->ref_store,
2094 diter->relative_path, 0,
2095 &iter->oid, &flags)) {
2096 error("bad ref for %s", diter->path.buf);
2097 continue;
2098 }
2099
2100 iter->base.refname = diter->relative_path;
2101 iter->base.oid = &iter->oid;
2102 iter->base.flags = flags;
2103 return ITER_OK;
2104 }
2105
2106 iter->dir_iterator = NULL;
2107 if (ref_iterator_abort(ref_iterator) == ITER_ERROR)
2108 ok = ITER_ERROR;
2109 return ok;
2110 }
2111
2112 static int files_reflog_iterator_peel(struct ref_iterator *ref_iterator,
2113 struct object_id *peeled)
2114 {
2115 BUG("ref_iterator_peel() called for reflog_iterator");
2116 }
2117
2118 static int files_reflog_iterator_abort(struct ref_iterator *ref_iterator)
2119 {
2120 struct files_reflog_iterator *iter =
2121 (struct files_reflog_iterator *)ref_iterator;
2122 int ok = ITER_DONE;
2123
2124 if (iter->dir_iterator)
2125 ok = dir_iterator_abort(iter->dir_iterator);
2126
2127 base_ref_iterator_free(ref_iterator);
2128 return ok;
2129 }
2130
2131 static struct ref_iterator_vtable files_reflog_iterator_vtable = {
2132 files_reflog_iterator_advance,
2133 files_reflog_iterator_peel,
2134 files_reflog_iterator_abort
2135 };
2136
2137 static struct ref_iterator *reflog_iterator_begin(struct ref_store *ref_store,
2138 const char *gitdir)
2139 {
2140 struct files_reflog_iterator *iter = xcalloc(1, sizeof(*iter));
2141 struct ref_iterator *ref_iterator = &iter->base;
2142 struct strbuf sb = STRBUF_INIT;
2143
2144 base_ref_iterator_init(ref_iterator, &files_reflog_iterator_vtable, 0);
2145 strbuf_addf(&sb, "%s/logs", gitdir);
2146 iter->dir_iterator = dir_iterator_begin(sb.buf);
2147 iter->ref_store = ref_store;
2148 strbuf_release(&sb);
2149
2150 return ref_iterator;
2151 }
2152
2153 static enum iterator_selection reflog_iterator_select(
2154 struct ref_iterator *iter_worktree,
2155 struct ref_iterator *iter_common,
2156 void *cb_data)
2157 {
2158 if (iter_worktree) {
2159 /*
2160 * We're a bit loose here. We probably should ignore
2161 * common refs if they are accidentally added as
2162 * per-worktree refs.
2163 */
2164 return ITER_SELECT_0;
2165 } else if (iter_common) {
2166 if (ref_type(iter_common->refname) == REF_TYPE_NORMAL)
2167 return ITER_SELECT_1;
2168
2169 /*
2170 * The main ref store may contain main worktree's
2171 * per-worktree refs, which should be ignored
2172 */
2173 return ITER_SKIP_1;
2174 } else
2175 return ITER_DONE;
2176 }
2177
2178 static struct ref_iterator *files_reflog_iterator_begin(struct ref_store *ref_store)
2179 {
2180 struct files_ref_store *refs =
2181 files_downcast(ref_store, REF_STORE_READ,
2182 "reflog_iterator_begin");
2183
2184 if (!strcmp(refs->gitdir, refs->gitcommondir)) {
2185 return reflog_iterator_begin(ref_store, refs->gitcommondir);
2186 } else {
2187 return merge_ref_iterator_begin(
2188 0,
2189 reflog_iterator_begin(ref_store, refs->gitdir),
2190 reflog_iterator_begin(ref_store, refs->gitcommondir),
2191 reflog_iterator_select, refs);
2192 }
2193 }
2194
2195 /*
2196 * If update is a direct update of head_ref (the reference pointed to
2197 * by HEAD), then add an extra REF_LOG_ONLY update for HEAD.
2198 */
2199 static int split_head_update(struct ref_update *update,
2200 struct ref_transaction *transaction,
2201 const char *head_ref,
2202 struct string_list *affected_refnames,
2203 struct strbuf *err)
2204 {
2205 struct string_list_item *item;
2206 struct ref_update *new_update;
2207
2208 if ((update->flags & REF_LOG_ONLY) ||
2209 (update->flags & REF_IS_PRUNING) ||
2210 (update->flags & REF_UPDATE_VIA_HEAD))
2211 return 0;
2212
2213 if (strcmp(update->refname, head_ref))
2214 return 0;
2215
2216 /*
2217 * First make sure that HEAD is not already in the
2218 * transaction. This check is O(lg N) in the transaction
2219 * size, but it happens at most once per transaction.
2220 */
2221 if (string_list_has_string(affected_refnames, "HEAD")) {
2222 /* An entry already existed */
2223 strbuf_addf(err,
2224 "multiple updates for 'HEAD' (including one "
2225 "via its referent '%s') are not allowed",
2226 update->refname);
2227 return TRANSACTION_NAME_CONFLICT;
2228 }
2229
2230 new_update = ref_transaction_add_update(
2231 transaction, "HEAD",
2232 update->flags | REF_LOG_ONLY | REF_NO_DEREF,
2233 &update->new_oid, &update->old_oid,
2234 update->msg);
2235
2236 /*
2237 * Add "HEAD". This insertion is O(N) in the transaction
2238 * size, but it happens at most once per transaction.
2239 * Add new_update->refname instead of a literal "HEAD".
2240 */
2241 if (strcmp(new_update->refname, "HEAD"))
2242 BUG("%s unexpectedly not 'HEAD'", new_update->refname);
2243 item = string_list_insert(affected_refnames, new_update->refname);
2244 item->util = new_update;
2245
2246 return 0;
2247 }
2248
2249 /*
2250 * update is for a symref that points at referent and doesn't have
2251 * REF_NO_DEREF set. Split it into two updates:
2252 * - The original update, but with REF_LOG_ONLY and REF_NO_DEREF set
2253 * - A new, separate update for the referent reference
2254 * Note that the new update will itself be subject to splitting when
2255 * the iteration gets to it.
2256 */
2257 static int split_symref_update(struct ref_update *update,
2258 const char *referent,
2259 struct ref_transaction *transaction,
2260 struct string_list *affected_refnames,
2261 struct strbuf *err)
2262 {
2263 struct string_list_item *item;
2264 struct ref_update *new_update;
2265 unsigned int new_flags;
2266
2267 /*
2268 * First make sure that referent is not already in the
2269 * transaction. This check is O(lg N) in the transaction
2270 * size, but it happens at most once per symref in a
2271 * transaction.
2272 */
2273 if (string_list_has_string(affected_refnames, referent)) {
2274 /* An entry already exists */
2275 strbuf_addf(err,
2276 "multiple updates for '%s' (including one "
2277 "via symref '%s') are not allowed",
2278 referent, update->refname);
2279 return TRANSACTION_NAME_CONFLICT;
2280 }
2281
2282 new_flags = update->flags;
2283 if (!strcmp(update->refname, "HEAD")) {
2284 /*
2285 * Record that the new update came via HEAD, so that
2286 * when we process it, split_head_update() doesn't try
2287 * to add another reflog update for HEAD. Note that
2288 * this bit will be propagated if the new_update
2289 * itself needs to be split.
2290 */
2291 new_flags |= REF_UPDATE_VIA_HEAD;
2292 }
2293
2294 new_update = ref_transaction_add_update(
2295 transaction, referent, new_flags,
2296 &update->new_oid, &update->old_oid,
2297 update->msg);
2298
2299 new_update->parent_update = update;
2300
2301 /*
2302 * Change the symbolic ref update to log only. Also, it
2303 * doesn't need to check its old OID value, as that will be
2304 * done when new_update is processed.
2305 */
2306 update->flags |= REF_LOG_ONLY | REF_NO_DEREF;
2307 update->flags &= ~REF_HAVE_OLD;
2308
2309 /*
2310 * Add the referent. This insertion is O(N) in the transaction
2311 * size, but it happens at most once per symref in a
2312 * transaction. Make sure to add new_update->refname, which will
2313 * be valid as long as affected_refnames is in use, and NOT
2314 * referent, which might soon be freed by our caller.
2315 */
2316 item = string_list_insert(affected_refnames, new_update->refname);
2317 if (item->util)
2318 BUG("%s unexpectedly found in affected_refnames",
2319 new_update->refname);
2320 item->util = new_update;
2321
2322 return 0;
2323 }
2324
2325 /*
2326 * Return the refname under which update was originally requested.
2327 */
2328 static const char *original_update_refname(struct ref_update *update)
2329 {
2330 while (update->parent_update)
2331 update = update->parent_update;
2332
2333 return update->refname;
2334 }
2335
2336 /*
2337 * Check whether the REF_HAVE_OLD and old_oid values stored in update
2338 * are consistent with oid, which is the reference's current value. If
2339 * everything is OK, return 0; otherwise, write an error message to
2340 * err and return -1.
2341 */
2342 static int check_old_oid(struct ref_update *update, struct object_id *oid,
2343 struct strbuf *err)
2344 {
2345 if (!(update->flags & REF_HAVE_OLD) ||
2346 oideq(oid, &update->old_oid))
2347 return 0;
2348
2349 if (is_null_oid(&update->old_oid))
2350 strbuf_addf(err, "cannot lock ref '%s': "
2351 "reference already exists",
2352 original_update_refname(update));
2353 else if (is_null_oid(oid))
2354 strbuf_addf(err, "cannot lock ref '%s': "
2355 "reference is missing but expected %s",
2356 original_update_refname(update),
2357 oid_to_hex(&update->old_oid));
2358 else
2359 strbuf_addf(err, "cannot lock ref '%s': "
2360 "is at %s but expected %s",
2361 original_update_refname(update),
2362 oid_to_hex(oid),
2363 oid_to_hex(&update->old_oid));
2364
2365 return -1;
2366 }
2367
2368 /*
2369 * Prepare for carrying out update:
2370 * - Lock the reference referred to by update.
2371 * - Read the reference under lock.
2372 * - Check that its old OID value (if specified) is correct, and in
2373 * any case record it in update->lock->old_oid for later use when
2374 * writing the reflog.
2375 * - If it is a symref update without REF_NO_DEREF, split it up into a
2376 * REF_LOG_ONLY update of the symref and add a separate update for
2377 * the referent to transaction.
2378 * - If it is an update of head_ref, add a corresponding REF_LOG_ONLY
2379 * update of HEAD.
2380 */
2381 static int lock_ref_for_update(struct files_ref_store *refs,
2382 struct ref_update *update,
2383 struct ref_transaction *transaction,
2384 const char *head_ref,
2385 struct string_list *affected_refnames,
2386 struct strbuf *err)
2387 {
2388 struct strbuf referent = STRBUF_INIT;
2389 int mustexist = (update->flags & REF_HAVE_OLD) &&
2390 !is_null_oid(&update->old_oid);
2391 int ret = 0;
2392 struct ref_lock *lock;
2393
2394 files_assert_main_repository(refs, "lock_ref_for_update");
2395
2396 if ((update->flags & REF_HAVE_NEW) && is_null_oid(&update->new_oid))
2397 update->flags |= REF_DELETING;
2398
2399 if (head_ref) {
2400 ret = split_head_update(update, transaction, head_ref,
2401 affected_refnames, err);
2402 if (ret)
2403 goto out;
2404 }
2405
2406 ret = lock_raw_ref(refs, update->refname, mustexist,
2407 affected_refnames, NULL,
2408 &lock, &referent,
2409 &update->type, err);
2410 if (ret) {
2411 char *reason;
2412
2413 reason = strbuf_detach(err, NULL);
2414 strbuf_addf(err, "cannot lock ref '%s': %s",
2415 original_update_refname(update), reason);
2416 free(reason);
2417 goto out;
2418 }
2419
2420 update->backend_data = lock;
2421
2422 if (update->type & REF_ISSYMREF) {
2423 if (update->flags & REF_NO_DEREF) {
2424 /*
2425 * We won't be reading the referent as part of
2426 * the transaction, so we have to read it here
2427 * to record and possibly check old_oid:
2428 */
2429 if (refs_read_ref_full(&refs->base,
2430 referent.buf, 0,
2431 &lock->old_oid, NULL)) {
2432 if (update->flags & REF_HAVE_OLD) {
2433 strbuf_addf(err, "cannot lock ref '%s': "
2434 "error reading reference",
2435 original_update_refname(update));
2436 ret = TRANSACTION_GENERIC_ERROR;
2437 goto out;
2438 }
2439 } else if (check_old_oid(update, &lock->old_oid, err)) {
2440 ret = TRANSACTION_GENERIC_ERROR;
2441 goto out;
2442 }
2443 } else {
2444 /*
2445 * Create a new update for the reference this
2446 * symref is pointing at. Also, we will record
2447 * and verify old_oid for this update as part
2448 * of processing the split-off update, so we
2449 * don't have to do it here.
2450 */
2451 ret = split_symref_update(update,
2452 referent.buf, transaction,
2453 affected_refnames, err);
2454 if (ret)
2455 goto out;
2456 }
2457 } else {
2458 struct ref_update *parent_update;
2459
2460 if (check_old_oid(update, &lock->old_oid, err)) {
2461 ret = TRANSACTION_GENERIC_ERROR;
2462 goto out;
2463 }
2464
2465 /*
2466 * If this update is happening indirectly because of a
2467 * symref update, record the old OID in the parent
2468 * update:
2469 */
2470 for (parent_update = update->parent_update;
2471 parent_update;
2472 parent_update = parent_update->parent_update) {
2473 struct ref_lock *parent_lock = parent_update->backend_data;
2474 oidcpy(&parent_lock->old_oid, &lock->old_oid);
2475 }
2476 }
2477
2478 if ((update->flags & REF_HAVE_NEW) &&
2479 !(update->flags & REF_DELETING) &&
2480 !(update->flags & REF_LOG_ONLY)) {
2481 if (!(update->type & REF_ISSYMREF) &&
2482 oideq(&lock->old_oid, &update->new_oid)) {
2483 /*
2484 * The reference already has the desired
2485 * value, so we don't need to write it.
2486 */
2487 } else if (write_ref_to_lockfile(lock, &update->new_oid,
2488 err)) {
2489 char *write_err = strbuf_detach(err, NULL);
2490
2491 /*
2492 * The lock was freed upon failure of
2493 * write_ref_to_lockfile():
2494 */
2495 update->backend_data = NULL;
2496 strbuf_addf(err,
2497 "cannot update ref '%s': %s",
2498 update->refname, write_err);
2499 free(write_err);
2500 ret = TRANSACTION_GENERIC_ERROR;
2501 goto out;
2502 } else {
2503 update->flags |= REF_NEEDS_COMMIT;
2504 }
2505 }
2506 if (!(update->flags & REF_NEEDS_COMMIT)) {
2507 /*
2508 * We didn't call write_ref_to_lockfile(), so
2509 * the lockfile is still open. Close it to
2510 * free up the file descriptor:
2511 */
2512 if (close_ref_gently(lock)) {
2513 strbuf_addf(err, "couldn't close '%s.lock'",
2514 update->refname);
2515 ret = TRANSACTION_GENERIC_ERROR;
2516 goto out;
2517 }
2518 }
2519
2520 out:
2521 strbuf_release(&referent);
2522 return ret;
2523 }
2524
2525 struct files_transaction_backend_data {
2526 struct ref_transaction *packed_transaction;
2527 int packed_refs_locked;
2528 };
2529
2530 /*
2531 * Unlock any references in `transaction` that are still locked, and
2532 * mark the transaction closed.
2533 */
2534 static void files_transaction_cleanup(struct files_ref_store *refs,
2535 struct ref_transaction *transaction)
2536 {
2537 size_t i;
2538 struct files_transaction_backend_data *backend_data =
2539 transaction->backend_data;
2540 struct strbuf err = STRBUF_INIT;
2541
2542 for (i = 0; i < transaction->nr; i++) {
2543 struct ref_update *update = transaction->updates[i];
2544 struct ref_lock *lock = update->backend_data;
2545
2546 if (lock) {
2547 unlock_ref(lock);
2548 update->backend_data = NULL;
2549 }
2550 }
2551
2552 if (backend_data->packed_transaction &&
2553 ref_transaction_abort(backend_data->packed_transaction, &err)) {
2554 error("error aborting transaction: %s", err.buf);
2555 strbuf_release(&err);
2556 }
2557
2558 if (backend_data->packed_refs_locked)
2559 packed_refs_unlock(refs->packed_ref_store);
2560
2561 free(backend_data);
2562
2563 transaction->state = REF_TRANSACTION_CLOSED;
2564 }
2565
2566 static int files_transaction_prepare(struct ref_store *ref_store,
2567 struct ref_transaction *transaction,
2568 struct strbuf *err)
2569 {
2570 struct files_ref_store *refs =
2571 files_downcast(ref_store, REF_STORE_WRITE,
2572 "ref_transaction_prepare");
2573 size_t i;
2574 int ret = 0;
2575 struct string_list affected_refnames = STRING_LIST_INIT_NODUP;
2576 char *head_ref = NULL;
2577 int head_type;
2578 struct files_transaction_backend_data *backend_data;
2579 struct ref_transaction *packed_transaction = NULL;
2580
2581 assert(err);
2582
2583 if (!transaction->nr)
2584 goto cleanup;
2585
2586 backend_data = xcalloc(1, sizeof(*backend_data));
2587 transaction->backend_data = backend_data;
2588
2589 /*
2590 * Fail if a refname appears more than once in the
2591 * transaction. (If we end up splitting up any updates using
2592 * split_symref_update() or split_head_update(), those
2593 * functions will check that the new updates don't have the
2594 * same refname as any existing ones.) Also fail if any of the
2595 * updates use REF_IS_PRUNING without REF_NO_DEREF.
2596 */
2597 for (i = 0; i < transaction->nr; i++) {
2598 struct ref_update *update = transaction->updates[i];
2599 struct string_list_item *item =
2600 string_list_append(&affected_refnames, update->refname);
2601
2602 if ((update->flags & REF_IS_PRUNING) &&
2603 !(update->flags & REF_NO_DEREF))
2604 BUG("REF_IS_PRUNING set without REF_NO_DEREF");
2605
2606 /*
2607 * We store a pointer to update in item->util, but at
2608 * the moment we never use the value of this field
2609 * except to check whether it is non-NULL.
2610 */
2611 item->util = update;
2612 }
2613 string_list_sort(&affected_refnames);
2614 if (ref_update_reject_duplicates(&affected_refnames, err)) {
2615 ret = TRANSACTION_GENERIC_ERROR;
2616 goto cleanup;
2617 }
2618
2619 /*
2620 * Special hack: If a branch is updated directly and HEAD
2621 * points to it (may happen on the remote side of a push
2622 * for example) then logically the HEAD reflog should be
2623 * updated too.
2624 *
2625 * A generic solution would require reverse symref lookups,
2626 * but finding all symrefs pointing to a given branch would be
2627 * rather costly for this rare event (the direct update of a
2628 * branch) to be worth it. So let's cheat and check with HEAD
2629 * only, which should cover 99% of all usage scenarios (even
2630 * 100% of the default ones).
2631 *
2632 * So if HEAD is a symbolic reference, then record the name of
2633 * the reference that it points to. If we see an update of
2634 * head_ref within the transaction, then split_head_update()
2635 * arranges for the reflog of HEAD to be updated, too.
2636 */
2637 head_ref = refs_resolve_refdup(ref_store, "HEAD",
2638 RESOLVE_REF_NO_RECURSE,
2639 NULL, &head_type);
2640
2641 if (head_ref && !(head_type & REF_ISSYMREF)) {
2642 FREE_AND_NULL(head_ref);
2643 }
2644
2645 /*
2646 * Acquire all locks, verify old values if provided, check
2647 * that new values are valid, and write new values to the
2648 * lockfiles, ready to be activated. Only keep one lockfile
2649 * open at a time to avoid running out of file descriptors.
2650 * Note that lock_ref_for_update() might append more updates
2651 * to the transaction.
2652 */
2653 for (i = 0; i < transaction->nr; i++) {
2654 struct ref_update *update = transaction->updates[i];
2655
2656 ret = lock_ref_for_update(refs, update, transaction,
2657 head_ref, &affected_refnames, err);
2658 if (ret)
2659 goto cleanup;
2660
2661 if (update->flags & REF_DELETING &&
2662 !(update->flags & REF_LOG_ONLY) &&
2663 !(update->flags & REF_IS_PRUNING)) {
2664 /*
2665 * This reference has to be deleted from
2666 * packed-refs if it exists there.
2667 */
2668 if (!packed_transaction) {
2669 packed_transaction = ref_store_transaction_begin(
2670 refs->packed_ref_store, err);
2671 if (!packed_transaction) {
2672 ret = TRANSACTION_GENERIC_ERROR;
2673 goto cleanup;
2674 }
2675
2676 backend_data->packed_transaction =
2677 packed_transaction;
2678 }
2679
2680 ref_transaction_add_update(
2681 packed_transaction, update->refname,
2682 REF_HAVE_NEW | REF_NO_DEREF,
2683 &update->new_oid, NULL,
2684 NULL);
2685 }
2686 }
2687
2688 if (packed_transaction) {
2689 if (packed_refs_lock(refs->packed_ref_store, 0, err)) {
2690 ret = TRANSACTION_GENERIC_ERROR;
2691 goto cleanup;
2692 }
2693 backend_data->packed_refs_locked = 1;
2694
2695 if (is_packed_transaction_needed(refs->packed_ref_store,
2696 packed_transaction)) {
2697 ret = ref_transaction_prepare(packed_transaction, err);
2698 } else {
2699 /*
2700 * We can skip rewriting the `packed-refs`
2701 * file. But we do need to leave it locked, so
2702 * that somebody else doesn't pack a reference
2703 * that we are trying to delete.
2704 */
2705 if (ref_transaction_abort(packed_transaction, err)) {
2706 ret = TRANSACTION_GENERIC_ERROR;
2707 goto cleanup;
2708 }
2709 backend_data->packed_transaction = NULL;
2710 }
2711 }
2712
2713 cleanup:
2714 free(head_ref);
2715 string_list_clear(&affected_refnames, 0);
2716
2717 if (ret)
2718 files_transaction_cleanup(refs, transaction);
2719 else
2720 transaction->state = REF_TRANSACTION_PREPARED;
2721
2722 return ret;
2723 }
2724
2725 static int files_transaction_finish(struct ref_store *ref_store,
2726 struct ref_transaction *transaction,
2727 struct strbuf *err)
2728 {
2729 struct files_ref_store *refs =
2730 files_downcast(ref_store, 0, "ref_transaction_finish");
2731 size_t i;
2732 int ret = 0;
2733 struct strbuf sb = STRBUF_INIT;
2734 struct files_transaction_backend_data *backend_data;
2735 struct ref_transaction *packed_transaction;
2736
2737
2738 assert(err);
2739
2740 if (!transaction->nr) {
2741 transaction->state = REF_TRANSACTION_CLOSED;
2742 return 0;
2743 }
2744
2745 backend_data = transaction->backend_data;
2746 packed_transaction = backend_data->packed_transaction;
2747
2748 /* Perform updates first so live commits remain referenced */
2749 for (i = 0; i < transaction->nr; i++) {
2750 struct ref_update *update = transaction->updates[i];
2751 struct ref_lock *lock = update->backend_data;
2752
2753 if (update->flags & REF_NEEDS_COMMIT ||
2754 update->flags & REF_LOG_ONLY) {
2755 if (files_log_ref_write(refs,
2756 lock->ref_name,
2757 &lock->old_oid,
2758 &update->new_oid,
2759 update->msg, update->flags,
2760 err)) {
2761 char *old_msg = strbuf_detach(err, NULL);
2762
2763 strbuf_addf(err, "cannot update the ref '%s': %s",
2764 lock->ref_name, old_msg);
2765 free(old_msg);
2766 unlock_ref(lock);
2767 update->backend_data = NULL;
2768 ret = TRANSACTION_GENERIC_ERROR;
2769 goto cleanup;
2770 }
2771 }
2772 if (update->flags & REF_NEEDS_COMMIT) {
2773 clear_loose_ref_cache(refs);
2774 if (commit_ref(lock)) {
2775 strbuf_addf(err, "couldn't set '%s'", lock->ref_name);
2776 unlock_ref(lock);
2777 update->backend_data = NULL;
2778 ret = TRANSACTION_GENERIC_ERROR;
2779 goto cleanup;
2780 }
2781 }
2782 }
2783
2784 /*
2785 * Now that updates are safely completed, we can perform
2786 * deletes. First delete the reflogs of any references that
2787 * will be deleted, since (in the unexpected event of an
2788 * error) leaving a reference without a reflog is less bad
2789 * than leaving a reflog without a reference (the latter is a
2790 * mildly invalid repository state):
2791 */
2792 for (i = 0; i < transaction->nr; i++) {
2793 struct ref_update *update = transaction->updates[i];
2794 if (update->flags & REF_DELETING &&
2795 !(update->flags & REF_LOG_ONLY) &&
2796 !(update->flags & REF_IS_PRUNING)) {
2797 strbuf_reset(&sb);
2798 files_reflog_path(refs, &sb, update->refname);
2799 if (!unlink_or_warn(sb.buf))
2800 try_remove_empty_parents(refs, update->refname,
2801 REMOVE_EMPTY_PARENTS_REFLOG);
2802 }
2803 }
2804
2805 /*
2806 * Perform deletes now that updates are safely completed.
2807 *
2808 * First delete any packed versions of the references, while
2809 * retaining the packed-refs lock:
2810 */
2811 if (packed_transaction) {
2812 ret = ref_transaction_commit(packed_transaction, err);
2813 ref_transaction_free(packed_transaction);
2814 packed_transaction = NULL;
2815 backend_data->packed_transaction = NULL;
2816 if (ret)
2817 goto cleanup;
2818 }
2819
2820 /* Now delete the loose versions of the references: */
2821 for (i = 0; i < transaction->nr; i++) {
2822 struct ref_update *update = transaction->updates[i];
2823 struct ref_lock *lock = update->backend_data;
2824
2825 if (update->flags & REF_DELETING &&
2826 !(update->flags & REF_LOG_ONLY)) {
2827 if (!(update->type & REF_ISPACKED) ||
2828 update->type & REF_ISSYMREF) {
2829 /* It is a loose reference. */
2830 strbuf_reset(&sb);
2831 files_ref_path(refs, &sb, lock->ref_name);
2832 if (unlink_or_msg(sb.buf, err)) {
2833 ret = TRANSACTION_GENERIC_ERROR;
2834 goto cleanup;
2835 }
2836 update->flags |= REF_DELETED_LOOSE;
2837 }
2838 }
2839 }
2840
2841 clear_loose_ref_cache(refs);
2842
2843 cleanup:
2844 files_transaction_cleanup(refs, transaction);
2845
2846 for (i = 0; i < transaction->nr; i++) {
2847 struct ref_update *update = transaction->updates[i];
2848
2849 if (update->flags & REF_DELETED_LOOSE) {
2850 /*
2851 * The loose reference was deleted. Delete any
2852 * empty parent directories. (Note that this
2853 * can only work because we have already
2854 * removed the lockfile.)
2855 */
2856 try_remove_empty_parents(refs, update->refname,
2857 REMOVE_EMPTY_PARENTS_REF);
2858 }
2859 }
2860
2861 strbuf_release(&sb);
2862 return ret;
2863 }
2864
2865 static int files_transaction_abort(struct ref_store *ref_store,
2866 struct ref_transaction *transaction,
2867 struct strbuf *err)
2868 {
2869 struct files_ref_store *refs =
2870 files_downcast(ref_store, 0, "ref_transaction_abort");
2871
2872 files_transaction_cleanup(refs, transaction);
2873 return 0;
2874 }
2875
2876 static int ref_present(const char *refname,
2877 const struct object_id *oid, int flags, void *cb_data)
2878 {
2879 struct string_list *affected_refnames = cb_data;
2880
2881 return string_list_has_string(affected_refnames, refname);
2882 }
2883
2884 static int files_initial_transaction_commit(struct ref_store *ref_store,
2885 struct ref_transaction *transaction,
2886 struct strbuf *err)
2887 {
2888 struct files_ref_store *refs =
2889 files_downcast(ref_store, REF_STORE_WRITE,
2890 "initial_ref_transaction_commit");
2891 size_t i;
2892 int ret = 0;
2893 struct string_list affected_refnames = STRING_LIST_INIT_NODUP;
2894 struct ref_transaction *packed_transaction = NULL;
2895
2896 assert(err);
2897
2898 if (transaction->state != REF_TRANSACTION_OPEN)
2899 BUG("commit called for transaction that is not open");
2900
2901 /* Fail if a refname appears more than once in the transaction: */
2902 for (i = 0; i < transaction->nr; i++)
2903 string_list_append(&affected_refnames,
2904 transaction->updates[i]->refname);
2905 string_list_sort(&affected_refnames);
2906 if (ref_update_reject_duplicates(&affected_refnames, err)) {
2907 ret = TRANSACTION_GENERIC_ERROR;
2908 goto cleanup;
2909 }
2910
2911 /*
2912 * It's really undefined to call this function in an active
2913 * repository or when there are existing references: we are
2914 * only locking and changing packed-refs, so (1) any
2915 * simultaneous processes might try to change a reference at
2916 * the same time we do, and (2) any existing loose versions of
2917 * the references that we are setting would have precedence
2918 * over our values. But some remote helpers create the remote
2919 * "HEAD" and "master" branches before calling this function,
2920 * so here we really only check that none of the references
2921 * that we are creating already exists.
2922 */
2923 if (refs_for_each_rawref(&refs->base, ref_present,
2924 &affected_refnames))
2925 BUG("initial ref transaction called with existing refs");
2926
2927 packed_transaction = ref_store_transaction_begin(refs->packed_ref_store, err);
2928 if (!packed_transaction) {
2929 ret = TRANSACTION_GENERIC_ERROR;
2930 goto cleanup;
2931 }
2932
2933 for (i = 0; i < transaction->nr; i++) {
2934 struct ref_update *update = transaction->updates[i];
2935
2936 if ((update->flags & REF_HAVE_OLD) &&
2937 !is_null_oid(&update->old_oid))
2938 BUG("initial ref transaction with old_sha1 set");
2939 if (refs_verify_refname_available(&refs->base, update->refname,
2940 &affected_refnames, NULL,
2941 err)) {
2942 ret = TRANSACTION_NAME_CONFLICT;
2943 goto cleanup;
2944 }
2945
2946 /*
2947 * Add a reference creation for this reference to the
2948 * packed-refs transaction:
2949 */
2950 ref_transaction_add_update(packed_transaction, update->refname,
2951 update->flags & ~REF_HAVE_OLD,
2952 &update->new_oid, &update->old_oid,
2953 NULL);
2954 }
2955
2956 if (packed_refs_lock(refs->packed_ref_store, 0, err)) {
2957 ret = TRANSACTION_GENERIC_ERROR;
2958 goto cleanup;
2959 }
2960
2961 if (initial_ref_transaction_commit(packed_transaction, err)) {
2962 ret = TRANSACTION_GENERIC_ERROR;
2963 }
2964
2965 packed_refs_unlock(refs->packed_ref_store);
2966 cleanup:
2967 if (packed_transaction)
2968 ref_transaction_free(packed_transaction);
2969 transaction->state = REF_TRANSACTION_CLOSED;
2970 string_list_clear(&affected_refnames, 0);
2971 return ret;
2972 }
2973
2974 struct expire_reflog_cb {
2975 unsigned int flags;
2976 reflog_expiry_should_prune_fn *should_prune_fn;
2977 void *policy_cb;
2978 FILE *newlog;
2979 struct object_id last_kept_oid;
2980 };
2981
2982 static int expire_reflog_ent(struct object_id *ooid, struct object_id *noid,
2983 const char *email, timestamp_t timestamp, int tz,
2984 const char *message, void *cb_data)
2985 {
2986 struct expire_reflog_cb *cb = cb_data;
2987 struct expire_reflog_policy_cb *policy_cb = cb->policy_cb;
2988
2989 if (cb->flags & EXPIRE_REFLOGS_REWRITE)
2990 ooid = &cb->last_kept_oid;
2991
2992 if ((*cb->should_prune_fn)(ooid, noid, email, timestamp, tz,
2993 message, policy_cb)) {
2994 if (!cb->newlog)
2995 printf("would prune %s", message);
2996 else if (cb->flags & EXPIRE_REFLOGS_VERBOSE)
2997 printf("prune %s", message);
2998 } else {
2999 if (cb->newlog) {
3000 fprintf(cb->newlog, "%s %s %s %"PRItime" %+05d\t%s",
3001 oid_to_hex(ooid), oid_to_hex(noid),
3002 email, timestamp, tz, message);
3003 oidcpy(&cb->last_kept_oid, noid);
3004 }
3005 if (cb->flags & EXPIRE_REFLOGS_VERBOSE)
3006 printf("keep %s", message);
3007 }
3008 return 0;
3009 }
3010
3011 static int files_reflog_expire(struct ref_store *ref_store,
3012 const char *refname, const struct object_id *oid,
3013 unsigned int flags,
3014 reflog_expiry_prepare_fn prepare_fn,
3015 reflog_expiry_should_prune_fn should_prune_fn,
3016 reflog_expiry_cleanup_fn cleanup_fn,
3017 void *policy_cb_data)
3018 {
3019 struct files_ref_store *refs =
3020 files_downcast(ref_store, REF_STORE_WRITE, "reflog_expire");
3021 struct lock_file reflog_lock = LOCK_INIT;
3022 struct expire_reflog_cb cb;
3023 struct ref_lock *lock;
3024 struct strbuf log_file_sb = STRBUF_INIT;
3025 char *log_file;
3026 int status = 0;
3027 int type;
3028 struct strbuf err = STRBUF_INIT;
3029
3030 memset(&cb, 0, sizeof(cb));
3031 cb.flags = flags;
3032 cb.policy_cb = policy_cb_data;
3033 cb.should_prune_fn = should_prune_fn;
3034
3035 /*
3036 * The reflog file is locked by holding the lock on the
3037 * reference itself, plus we might need to update the
3038 * reference if --updateref was specified:
3039 */
3040 lock = lock_ref_oid_basic(refs, refname, oid,
3041 NULL, NULL, REF_NO_DEREF,
3042 &type, &err);
3043 if (!lock) {
3044 error("cannot lock ref '%s': %s", refname, err.buf);
3045 strbuf_release(&err);
3046 return -1;
3047 }
3048 if (!refs_reflog_exists(ref_store, refname)) {
3049 unlock_ref(lock);
3050 return 0;
3051 }
3052
3053 files_reflog_path(refs, &log_file_sb, refname);
3054 log_file = strbuf_detach(&log_file_sb, NULL);
3055 if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {
3056 /*
3057 * Even though holding $GIT_DIR/logs/$reflog.lock has
3058 * no locking implications, we use the lock_file
3059 * machinery here anyway because it does a lot of the
3060 * work we need, including cleaning up if the program
3061 * exits unexpectedly.
3062 */
3063 if (hold_lock_file_for_update(&reflog_lock, log_file, 0) < 0) {
3064 struct strbuf err = STRBUF_INIT;
3065 unable_to_lock_message(log_file, errno, &err);
3066 error("%s", err.buf);
3067 strbuf_release(&err);
3068 goto failure;
3069 }
3070 cb.newlog = fdopen_lock_file(&reflog_lock, "w");
3071 if (!cb.newlog) {
3072 error("cannot fdopen %s (%s)",
3073 get_lock_file_path(&reflog_lock), strerror(errno));
3074 goto failure;
3075 }
3076 }
3077
3078 (*prepare_fn)(refname, oid, cb.policy_cb);
3079 refs_for_each_reflog_ent(ref_store, refname, expire_reflog_ent, &cb);
3080 (*cleanup_fn)(cb.policy_cb);
3081
3082 if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {
3083 /*
3084 * It doesn't make sense to adjust a reference pointed
3085 * to by a symbolic ref based on expiring entries in
3086 * the symbolic reference's reflog. Nor can we update
3087 * a reference if there are no remaining reflog
3088 * entries.
3089 */
3090 int update = (flags & EXPIRE_REFLOGS_UPDATE_REF) &&
3091 !(type & REF_ISSYMREF) &&
3092 !is_null_oid(&cb.last_kept_oid);
3093
3094 if (close_lock_file_gently(&reflog_lock)) {
3095 status |= error("couldn't write %s: %s", log_file,
3096 strerror(errno));
3097 rollback_lock_file(&reflog_lock);
3098 } else if (update &&
3099 (write_in_full(get_lock_file_fd(&lock->lk),
3100 oid_to_hex(&cb.last_kept_oid), the_hash_algo->hexsz) < 0 ||
3101 write_str_in_full(get_lock_file_fd(&lock->lk), "\n") < 0 ||
3102 close_ref_gently(lock) < 0)) {
3103 status |= error("couldn't write %s",
3104 get_lock_file_path(&lock->lk));
3105 rollback_lock_file(&reflog_lock);
3106 } else if (commit_lock_file(&reflog_lock)) {
3107 status |= error("unable to write reflog '%s' (%s)",
3108 log_file, strerror(errno));
3109 } else if (update && commit_ref(lock)) {
3110 status |= error("couldn't set %s", lock->ref_name);
3111 }
3112 }
3113 free(log_file);
3114 unlock_ref(lock);
3115 return status;
3116
3117 failure:
3118 rollback_lock_file(&reflog_lock);
3119 free(log_file);
3120 unlock_ref(lock);
3121 return -1;
3122 }
3123
3124 static int files_init_db(struct ref_store *ref_store, struct strbuf *err)
3125 {
3126 struct files_ref_store *refs =
3127 files_downcast(ref_store, REF_STORE_WRITE, "init_db");
3128 struct strbuf sb = STRBUF_INIT;
3129
3130 /*
3131 * Create .git/refs/{heads,tags}
3132 */
3133 files_ref_path(refs, &sb, "refs/heads");
3134 safe_create_dir(sb.buf, 1);
3135
3136 strbuf_reset(&sb);
3137 files_ref_path(refs, &sb, "refs/tags");
3138 safe_create_dir(sb.buf, 1);
3139
3140 strbuf_release(&sb);
3141 return 0;
3142 }
3143
3144 struct ref_storage_be refs_be_files = {
3145 NULL,
3146 "files",
3147 files_ref_store_create,
3148 files_init_db,
3149 files_transaction_prepare,
3150 files_transaction_finish,
3151 files_transaction_abort,
3152 files_initial_transaction_commit,
3153
3154 files_pack_refs,
3155 files_create_symref,
3156 files_delete_refs,
3157 files_rename_ref,
3158 files_copy_ref,
3159
3160 files_ref_iterator_begin,
3161 files_read_raw_ref,
3162
3163 files_reflog_iterator_begin,
3164 files_for_each_reflog_ent,
3165 files_for_each_reflog_ent_reverse,
3166 files_reflog_exists,
3167 files_create_reflog,
3168 files_delete_reflog,
3169 files_reflog_expire
3170 };