Merge branch 'dl/config-alias-doc' into maint
[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 * Manually add refs/bisect, refs/rewritten and refs/worktree, which, being
219 * per-worktree, might not appear in the directory listing for
220 * refs/ in the main repo.
221 */
222 static void add_per_worktree_entries_to_dir(struct ref_dir *dir, const char *dirname)
223 {
224 const char *prefixes[] = { "refs/bisect/", "refs/worktree/", "refs/rewritten/" };
225 int ip;
226
227 if (strcmp(dirname, "refs/"))
228 return;
229
230 for (ip = 0; ip < ARRAY_SIZE(prefixes); ip++) {
231 const char *prefix = prefixes[ip];
232 int prefix_len = strlen(prefix);
233 struct ref_entry *child_entry;
234 int pos;
235
236 pos = search_ref_dir(dir, prefix, prefix_len);
237 if (pos >= 0)
238 continue;
239 child_entry = create_dir_entry(dir->cache, prefix, prefix_len, 1);
240 add_entry_to_dir(dir, child_entry);
241 }
242 }
243
244 /*
245 * Read the loose references from the namespace dirname into dir
246 * (without recursing). dirname must end with '/'. dir must be the
247 * directory entry corresponding to dirname.
248 */
249 static void loose_fill_ref_dir(struct ref_store *ref_store,
250 struct ref_dir *dir, const char *dirname)
251 {
252 struct files_ref_store *refs =
253 files_downcast(ref_store, REF_STORE_READ, "fill_ref_dir");
254 DIR *d;
255 struct dirent *de;
256 int dirnamelen = strlen(dirname);
257 struct strbuf refname;
258 struct strbuf path = STRBUF_INIT;
259 size_t path_baselen;
260
261 files_ref_path(refs, &path, dirname);
262 path_baselen = path.len;
263
264 d = opendir(path.buf);
265 if (!d) {
266 strbuf_release(&path);
267 return;
268 }
269
270 strbuf_init(&refname, dirnamelen + 257);
271 strbuf_add(&refname, dirname, dirnamelen);
272
273 while ((de = readdir(d)) != NULL) {
274 struct object_id oid;
275 struct stat st;
276 int flag;
277
278 if (de->d_name[0] == '.')
279 continue;
280 if (ends_with(de->d_name, ".lock"))
281 continue;
282 strbuf_addstr(&refname, de->d_name);
283 strbuf_addstr(&path, de->d_name);
284 if (stat(path.buf, &st) < 0) {
285 ; /* silently ignore */
286 } else if (S_ISDIR(st.st_mode)) {
287 strbuf_addch(&refname, '/');
288 add_entry_to_dir(dir,
289 create_dir_entry(dir->cache, refname.buf,
290 refname.len, 1));
291 } else {
292 if (!refs_resolve_ref_unsafe(&refs->base,
293 refname.buf,
294 RESOLVE_REF_READING,
295 &oid, &flag)) {
296 oidclr(&oid);
297 flag |= REF_ISBROKEN;
298 } else if (is_null_oid(&oid)) {
299 /*
300 * It is so astronomically unlikely
301 * that null_oid is the OID of an
302 * actual object that we consider its
303 * appearance in a loose reference
304 * file to be repo corruption
305 * (probably due to a software bug).
306 */
307 flag |= REF_ISBROKEN;
308 }
309
310 if (check_refname_format(refname.buf,
311 REFNAME_ALLOW_ONELEVEL)) {
312 if (!refname_is_safe(refname.buf))
313 die("loose refname is dangerous: %s", refname.buf);
314 oidclr(&oid);
315 flag |= REF_BAD_NAME | REF_ISBROKEN;
316 }
317 add_entry_to_dir(dir,
318 create_ref_entry(refname.buf, &oid, flag));
319 }
320 strbuf_setlen(&refname, dirnamelen);
321 strbuf_setlen(&path, path_baselen);
322 }
323 strbuf_release(&refname);
324 strbuf_release(&path);
325 closedir(d);
326
327 add_per_worktree_entries_to_dir(dir, dirname);
328 }
329
330 static struct ref_cache *get_loose_ref_cache(struct files_ref_store *refs)
331 {
332 if (!refs->loose) {
333 /*
334 * Mark the top-level directory complete because we
335 * are about to read the only subdirectory that can
336 * hold references:
337 */
338 refs->loose = create_ref_cache(&refs->base, loose_fill_ref_dir);
339
340 /* We're going to fill the top level ourselves: */
341 refs->loose->root->flag &= ~REF_INCOMPLETE;
342
343 /*
344 * Add an incomplete entry for "refs/" (to be filled
345 * lazily):
346 */
347 add_entry_to_dir(get_ref_dir(refs->loose->root),
348 create_dir_entry(refs->loose, "refs/", 5, 1));
349 }
350 return refs->loose;
351 }
352
353 static int files_read_raw_ref(struct ref_store *ref_store,
354 const char *refname, struct object_id *oid,
355 struct strbuf *referent, unsigned int *type)
356 {
357 struct files_ref_store *refs =
358 files_downcast(ref_store, REF_STORE_READ, "read_raw_ref");
359 struct strbuf sb_contents = STRBUF_INIT;
360 struct strbuf sb_path = STRBUF_INIT;
361 const char *path;
362 const char *buf;
363 const char *p;
364 struct stat st;
365 int fd;
366 int ret = -1;
367 int save_errno;
368 int remaining_retries = 3;
369
370 *type = 0;
371 strbuf_reset(&sb_path);
372
373 files_ref_path(refs, &sb_path, refname);
374
375 path = sb_path.buf;
376
377 stat_ref:
378 /*
379 * We might have to loop back here to avoid a race
380 * condition: first we lstat() the file, then we try
381 * to read it as a link or as a file. But if somebody
382 * changes the type of the file (file <-> directory
383 * <-> symlink) between the lstat() and reading, then
384 * we don't want to report that as an error but rather
385 * try again starting with the lstat().
386 *
387 * We'll keep a count of the retries, though, just to avoid
388 * any confusing situation sending us into an infinite loop.
389 */
390
391 if (remaining_retries-- <= 0)
392 goto out;
393
394 if (lstat(path, &st) < 0) {
395 if (errno != ENOENT)
396 goto out;
397 if (refs_read_raw_ref(refs->packed_ref_store, refname,
398 oid, referent, type)) {
399 errno = ENOENT;
400 goto out;
401 }
402 ret = 0;
403 goto out;
404 }
405
406 /* Follow "normalized" - ie "refs/.." symlinks by hand */
407 if (S_ISLNK(st.st_mode)) {
408 strbuf_reset(&sb_contents);
409 if (strbuf_readlink(&sb_contents, path, st.st_size) < 0) {
410 if (errno == ENOENT || errno == EINVAL)
411 /* inconsistent with lstat; retry */
412 goto stat_ref;
413 else
414 goto out;
415 }
416 if (starts_with(sb_contents.buf, "refs/") &&
417 !check_refname_format(sb_contents.buf, 0)) {
418 strbuf_swap(&sb_contents, referent);
419 *type |= REF_ISSYMREF;
420 ret = 0;
421 goto out;
422 }
423 /*
424 * It doesn't look like a refname; fall through to just
425 * treating it like a non-symlink, and reading whatever it
426 * points to.
427 */
428 }
429
430 /* Is it a directory? */
431 if (S_ISDIR(st.st_mode)) {
432 /*
433 * Even though there is a directory where the loose
434 * ref is supposed to be, there could still be a
435 * packed ref:
436 */
437 if (refs_read_raw_ref(refs->packed_ref_store, refname,
438 oid, referent, type)) {
439 errno = EISDIR;
440 goto out;
441 }
442 ret = 0;
443 goto out;
444 }
445
446 /*
447 * Anything else, just open it and try to use it as
448 * a ref
449 */
450 fd = open(path, O_RDONLY);
451 if (fd < 0) {
452 if (errno == ENOENT && !S_ISLNK(st.st_mode))
453 /* inconsistent with lstat; retry */
454 goto stat_ref;
455 else
456 goto out;
457 }
458 strbuf_reset(&sb_contents);
459 if (strbuf_read(&sb_contents, fd, 256) < 0) {
460 int save_errno = errno;
461 close(fd);
462 errno = save_errno;
463 goto out;
464 }
465 close(fd);
466 strbuf_rtrim(&sb_contents);
467 buf = sb_contents.buf;
468 if (starts_with(buf, "ref:")) {
469 buf += 4;
470 while (isspace(*buf))
471 buf++;
472
473 strbuf_reset(referent);
474 strbuf_addstr(referent, buf);
475 *type |= REF_ISSYMREF;
476 ret = 0;
477 goto out;
478 }
479
480 /*
481 * Please note that FETCH_HEAD has additional
482 * data after the sha.
483 */
484 if (parse_oid_hex(buf, oid, &p) ||
485 (*p != '\0' && !isspace(*p))) {
486 *type |= REF_ISBROKEN;
487 errno = EINVAL;
488 goto out;
489 }
490
491 ret = 0;
492
493 out:
494 save_errno = errno;
495 strbuf_release(&sb_path);
496 strbuf_release(&sb_contents);
497 errno = save_errno;
498 return ret;
499 }
500
501 static void unlock_ref(struct ref_lock *lock)
502 {
503 rollback_lock_file(&lock->lk);
504 free(lock->ref_name);
505 free(lock);
506 }
507
508 /*
509 * Lock refname, without following symrefs, and set *lock_p to point
510 * at a newly-allocated lock object. Fill in lock->old_oid, referent,
511 * and type similarly to read_raw_ref().
512 *
513 * The caller must verify that refname is a "safe" reference name (in
514 * the sense of refname_is_safe()) before calling this function.
515 *
516 * If the reference doesn't already exist, verify that refname doesn't
517 * have a D/F conflict with any existing references. extras and skip
518 * are passed to refs_verify_refname_available() for this check.
519 *
520 * If mustexist is not set and the reference is not found or is
521 * broken, lock the reference anyway but clear old_oid.
522 *
523 * Return 0 on success. On failure, write an error message to err and
524 * return TRANSACTION_NAME_CONFLICT or TRANSACTION_GENERIC_ERROR.
525 *
526 * Implementation note: This function is basically
527 *
528 * lock reference
529 * read_raw_ref()
530 *
531 * but it includes a lot more code to
532 * - Deal with possible races with other processes
533 * - Avoid calling refs_verify_refname_available() when it can be
534 * avoided, namely if we were successfully able to read the ref
535 * - Generate informative error messages in the case of failure
536 */
537 static int lock_raw_ref(struct files_ref_store *refs,
538 const char *refname, int mustexist,
539 const struct string_list *extras,
540 const struct string_list *skip,
541 struct ref_lock **lock_p,
542 struct strbuf *referent,
543 unsigned int *type,
544 struct strbuf *err)
545 {
546 struct ref_lock *lock;
547 struct strbuf ref_file = STRBUF_INIT;
548 int attempts_remaining = 3;
549 int ret = TRANSACTION_GENERIC_ERROR;
550
551 assert(err);
552 files_assert_main_repository(refs, "lock_raw_ref");
553
554 *type = 0;
555
556 /* First lock the file so it can't change out from under us. */
557
558 *lock_p = lock = xcalloc(1, sizeof(*lock));
559
560 lock->ref_name = xstrdup(refname);
561 files_ref_path(refs, &ref_file, refname);
562
563 retry:
564 switch (safe_create_leading_directories(ref_file.buf)) {
565 case SCLD_OK:
566 break; /* success */
567 case SCLD_EXISTS:
568 /*
569 * Suppose refname is "refs/foo/bar". We just failed
570 * to create the containing directory, "refs/foo",
571 * because there was a non-directory in the way. This
572 * indicates a D/F conflict, probably because of
573 * another reference such as "refs/foo". There is no
574 * reason to expect this error to be transitory.
575 */
576 if (refs_verify_refname_available(&refs->base, refname,
577 extras, skip, err)) {
578 if (mustexist) {
579 /*
580 * To the user the relevant error is
581 * that the "mustexist" reference is
582 * missing:
583 */
584 strbuf_reset(err);
585 strbuf_addf(err, "unable to resolve reference '%s'",
586 refname);
587 } else {
588 /*
589 * The error message set by
590 * refs_verify_refname_available() is
591 * OK.
592 */
593 ret = TRANSACTION_NAME_CONFLICT;
594 }
595 } else {
596 /*
597 * The file that is in the way isn't a loose
598 * reference. Report it as a low-level
599 * failure.
600 */
601 strbuf_addf(err, "unable to create lock file %s.lock; "
602 "non-directory in the way",
603 ref_file.buf);
604 }
605 goto error_return;
606 case SCLD_VANISHED:
607 /* Maybe another process was tidying up. Try again. */
608 if (--attempts_remaining > 0)
609 goto retry;
610 /* fall through */
611 default:
612 strbuf_addf(err, "unable to create directory for %s",
613 ref_file.buf);
614 goto error_return;
615 }
616
617 if (hold_lock_file_for_update_timeout(
618 &lock->lk, ref_file.buf, LOCK_NO_DEREF,
619 get_files_ref_lock_timeout_ms()) < 0) {
620 if (errno == ENOENT && --attempts_remaining > 0) {
621 /*
622 * Maybe somebody just deleted one of the
623 * directories leading to ref_file. Try
624 * again:
625 */
626 goto retry;
627 } else {
628 unable_to_lock_message(ref_file.buf, errno, err);
629 goto error_return;
630 }
631 }
632
633 /*
634 * Now we hold the lock and can read the reference without
635 * fear that its value will change.
636 */
637
638 if (files_read_raw_ref(&refs->base, refname,
639 &lock->old_oid, referent, type)) {
640 if (errno == ENOENT) {
641 if (mustexist) {
642 /* Garden variety missing reference. */
643 strbuf_addf(err, "unable to resolve reference '%s'",
644 refname);
645 goto error_return;
646 } else {
647 /*
648 * Reference is missing, but that's OK. We
649 * know that there is not a conflict with
650 * another loose reference because
651 * (supposing that we are trying to lock
652 * reference "refs/foo/bar"):
653 *
654 * - We were successfully able to create
655 * the lockfile refs/foo/bar.lock, so we
656 * know there cannot be a loose reference
657 * named "refs/foo".
658 *
659 * - We got ENOENT and not EISDIR, so we
660 * know that there cannot be a loose
661 * reference named "refs/foo/bar/baz".
662 */
663 }
664 } else if (errno == EISDIR) {
665 /*
666 * There is a directory in the way. It might have
667 * contained references that have been deleted. If
668 * we don't require that the reference already
669 * exists, try to remove the directory so that it
670 * doesn't cause trouble when we want to rename the
671 * lockfile into place later.
672 */
673 if (mustexist) {
674 /* Garden variety missing reference. */
675 strbuf_addf(err, "unable to resolve reference '%s'",
676 refname);
677 goto error_return;
678 } else if (remove_dir_recursively(&ref_file,
679 REMOVE_DIR_EMPTY_ONLY)) {
680 if (refs_verify_refname_available(
681 &refs->base, refname,
682 extras, skip, err)) {
683 /*
684 * The error message set by
685 * verify_refname_available() is OK.
686 */
687 ret = TRANSACTION_NAME_CONFLICT;
688 goto error_return;
689 } else {
690 /*
691 * We can't delete the directory,
692 * but we also don't know of any
693 * references that it should
694 * contain.
695 */
696 strbuf_addf(err, "there is a non-empty directory '%s' "
697 "blocking reference '%s'",
698 ref_file.buf, refname);
699 goto error_return;
700 }
701 }
702 } else if (errno == EINVAL && (*type & REF_ISBROKEN)) {
703 strbuf_addf(err, "unable to resolve reference '%s': "
704 "reference broken", refname);
705 goto error_return;
706 } else {
707 strbuf_addf(err, "unable to resolve reference '%s': %s",
708 refname, strerror(errno));
709 goto error_return;
710 }
711
712 /*
713 * If the ref did not exist and we are creating it,
714 * make sure there is no existing packed ref that
715 * conflicts with refname:
716 */
717 if (refs_verify_refname_available(
718 refs->packed_ref_store, refname,
719 extras, skip, err))
720 goto error_return;
721 }
722
723 ret = 0;
724 goto out;
725
726 error_return:
727 unlock_ref(lock);
728 *lock_p = NULL;
729
730 out:
731 strbuf_release(&ref_file);
732 return ret;
733 }
734
735 struct files_ref_iterator {
736 struct ref_iterator base;
737
738 struct ref_iterator *iter0;
739 unsigned int flags;
740 };
741
742 static int files_ref_iterator_advance(struct ref_iterator *ref_iterator)
743 {
744 struct files_ref_iterator *iter =
745 (struct files_ref_iterator *)ref_iterator;
746 int ok;
747
748 while ((ok = ref_iterator_advance(iter->iter0)) == ITER_OK) {
749 if (iter->flags & DO_FOR_EACH_PER_WORKTREE_ONLY &&
750 ref_type(iter->iter0->refname) != REF_TYPE_PER_WORKTREE)
751 continue;
752
753 if (!(iter->flags & DO_FOR_EACH_INCLUDE_BROKEN) &&
754 !ref_resolves_to_object(iter->iter0->refname,
755 iter->iter0->oid,
756 iter->iter0->flags))
757 continue;
758
759 iter->base.refname = iter->iter0->refname;
760 iter->base.oid = iter->iter0->oid;
761 iter->base.flags = iter->iter0->flags;
762 return ITER_OK;
763 }
764
765 iter->iter0 = NULL;
766 if (ref_iterator_abort(ref_iterator) != ITER_DONE)
767 ok = ITER_ERROR;
768
769 return ok;
770 }
771
772 static int files_ref_iterator_peel(struct ref_iterator *ref_iterator,
773 struct object_id *peeled)
774 {
775 struct files_ref_iterator *iter =
776 (struct files_ref_iterator *)ref_iterator;
777
778 return ref_iterator_peel(iter->iter0, peeled);
779 }
780
781 static int files_ref_iterator_abort(struct ref_iterator *ref_iterator)
782 {
783 struct files_ref_iterator *iter =
784 (struct files_ref_iterator *)ref_iterator;
785 int ok = ITER_DONE;
786
787 if (iter->iter0)
788 ok = ref_iterator_abort(iter->iter0);
789
790 base_ref_iterator_free(ref_iterator);
791 return ok;
792 }
793
794 static struct ref_iterator_vtable files_ref_iterator_vtable = {
795 files_ref_iterator_advance,
796 files_ref_iterator_peel,
797 files_ref_iterator_abort
798 };
799
800 static struct ref_iterator *files_ref_iterator_begin(
801 struct ref_store *ref_store,
802 const char *prefix, unsigned int flags)
803 {
804 struct files_ref_store *refs;
805 struct ref_iterator *loose_iter, *packed_iter, *overlay_iter;
806 struct files_ref_iterator *iter;
807 struct ref_iterator *ref_iterator;
808 unsigned int required_flags = REF_STORE_READ;
809
810 if (!(flags & DO_FOR_EACH_INCLUDE_BROKEN))
811 required_flags |= REF_STORE_ODB;
812
813 refs = files_downcast(ref_store, required_flags, "ref_iterator_begin");
814
815 /*
816 * We must make sure that all loose refs are read before
817 * accessing the packed-refs file; this avoids a race
818 * condition if loose refs are migrated to the packed-refs
819 * file by a simultaneous process, but our in-memory view is
820 * from before the migration. We ensure this as follows:
821 * First, we call start the loose refs iteration with its
822 * `prime_ref` argument set to true. This causes the loose
823 * references in the subtree to be pre-read into the cache.
824 * (If they've already been read, that's OK; we only need to
825 * guarantee that they're read before the packed refs, not
826 * *how much* before.) After that, we call
827 * packed_ref_iterator_begin(), which internally checks
828 * whether the packed-ref cache is up to date with what is on
829 * disk, and re-reads it if not.
830 */
831
832 loose_iter = cache_ref_iterator_begin(get_loose_ref_cache(refs),
833 prefix, 1);
834
835 /*
836 * The packed-refs file might contain broken references, for
837 * example an old version of a reference that points at an
838 * object that has since been garbage-collected. This is OK as
839 * long as there is a corresponding loose reference that
840 * overrides it, and we don't want to emit an error message in
841 * this case. So ask the packed_ref_store for all of its
842 * references, and (if needed) do our own check for broken
843 * ones in files_ref_iterator_advance(), after we have merged
844 * the packed and loose references.
845 */
846 packed_iter = refs_ref_iterator_begin(
847 refs->packed_ref_store, prefix, 0,
848 DO_FOR_EACH_INCLUDE_BROKEN);
849
850 overlay_iter = overlay_ref_iterator_begin(loose_iter, packed_iter);
851
852 iter = xcalloc(1, sizeof(*iter));
853 ref_iterator = &iter->base;
854 base_ref_iterator_init(ref_iterator, &files_ref_iterator_vtable,
855 overlay_iter->ordered);
856 iter->iter0 = overlay_iter;
857 iter->flags = flags;
858
859 return ref_iterator;
860 }
861
862 /*
863 * Verify that the reference locked by lock has the value old_oid
864 * (unless it is NULL). Fail if the reference doesn't exist and
865 * mustexist is set. Return 0 on success. On error, write an error
866 * message to err, set errno, and return a negative value.
867 */
868 static int verify_lock(struct ref_store *ref_store, struct ref_lock *lock,
869 const struct object_id *old_oid, int mustexist,
870 struct strbuf *err)
871 {
872 assert(err);
873
874 if (refs_read_ref_full(ref_store, lock->ref_name,
875 mustexist ? RESOLVE_REF_READING : 0,
876 &lock->old_oid, NULL)) {
877 if (old_oid) {
878 int save_errno = errno;
879 strbuf_addf(err, "can't verify ref '%s'", lock->ref_name);
880 errno = save_errno;
881 return -1;
882 } else {
883 oidclr(&lock->old_oid);
884 return 0;
885 }
886 }
887 if (old_oid && !oideq(&lock->old_oid, old_oid)) {
888 strbuf_addf(err, "ref '%s' is at %s but expected %s",
889 lock->ref_name,
890 oid_to_hex(&lock->old_oid),
891 oid_to_hex(old_oid));
892 errno = EBUSY;
893 return -1;
894 }
895 return 0;
896 }
897
898 static int remove_empty_directories(struct strbuf *path)
899 {
900 /*
901 * we want to create a file but there is a directory there;
902 * if that is an empty directory (or a directory that contains
903 * only empty directories), remove them.
904 */
905 return remove_dir_recursively(path, REMOVE_DIR_EMPTY_ONLY);
906 }
907
908 static int create_reflock(const char *path, void *cb)
909 {
910 struct lock_file *lk = cb;
911
912 return hold_lock_file_for_update_timeout(
913 lk, path, LOCK_NO_DEREF,
914 get_files_ref_lock_timeout_ms()) < 0 ? -1 : 0;
915 }
916
917 /*
918 * Locks a ref returning the lock on success and NULL on failure.
919 * On failure errno is set to something meaningful.
920 */
921 static struct ref_lock *lock_ref_oid_basic(struct files_ref_store *refs,
922 const char *refname,
923 const struct object_id *old_oid,
924 const struct string_list *extras,
925 const struct string_list *skip,
926 unsigned int flags, int *type,
927 struct strbuf *err)
928 {
929 struct strbuf ref_file = STRBUF_INIT;
930 struct ref_lock *lock;
931 int last_errno = 0;
932 int mustexist = (old_oid && !is_null_oid(old_oid));
933 int resolve_flags = RESOLVE_REF_NO_RECURSE;
934 int resolved;
935
936 files_assert_main_repository(refs, "lock_ref_oid_basic");
937 assert(err);
938
939 lock = xcalloc(1, sizeof(struct ref_lock));
940
941 if (mustexist)
942 resolve_flags |= RESOLVE_REF_READING;
943 if (flags & REF_DELETING)
944 resolve_flags |= RESOLVE_REF_ALLOW_BAD_NAME;
945
946 files_ref_path(refs, &ref_file, refname);
947 resolved = !!refs_resolve_ref_unsafe(&refs->base,
948 refname, resolve_flags,
949 &lock->old_oid, type);
950 if (!resolved && errno == EISDIR) {
951 /*
952 * we are trying to lock foo but we used to
953 * have foo/bar which now does not exist;
954 * it is normal for the empty directory 'foo'
955 * to remain.
956 */
957 if (remove_empty_directories(&ref_file)) {
958 last_errno = errno;
959 if (!refs_verify_refname_available(
960 &refs->base,
961 refname, extras, skip, err))
962 strbuf_addf(err, "there are still refs under '%s'",
963 refname);
964 goto error_return;
965 }
966 resolved = !!refs_resolve_ref_unsafe(&refs->base,
967 refname, resolve_flags,
968 &lock->old_oid, type);
969 }
970 if (!resolved) {
971 last_errno = errno;
972 if (last_errno != ENOTDIR ||
973 !refs_verify_refname_available(&refs->base, refname,
974 extras, skip, err))
975 strbuf_addf(err, "unable to resolve reference '%s': %s",
976 refname, strerror(last_errno));
977
978 goto error_return;
979 }
980
981 /*
982 * If the ref did not exist and we are creating it, make sure
983 * there is no existing packed ref whose name begins with our
984 * refname, nor a packed ref whose name is a proper prefix of
985 * our refname.
986 */
987 if (is_null_oid(&lock->old_oid) &&
988 refs_verify_refname_available(refs->packed_ref_store, refname,
989 extras, skip, err)) {
990 last_errno = ENOTDIR;
991 goto error_return;
992 }
993
994 lock->ref_name = xstrdup(refname);
995
996 if (raceproof_create_file(ref_file.buf, create_reflock, &lock->lk)) {
997 last_errno = errno;
998 unable_to_lock_message(ref_file.buf, errno, err);
999 goto error_return;
1000 }
1001
1002 if (verify_lock(&refs->base, lock, old_oid, mustexist, err)) {
1003 last_errno = errno;
1004 goto error_return;
1005 }
1006 goto out;
1007
1008 error_return:
1009 unlock_ref(lock);
1010 lock = NULL;
1011
1012 out:
1013 strbuf_release(&ref_file);
1014 errno = last_errno;
1015 return lock;
1016 }
1017
1018 struct ref_to_prune {
1019 struct ref_to_prune *next;
1020 struct object_id oid;
1021 char name[FLEX_ARRAY];
1022 };
1023
1024 enum {
1025 REMOVE_EMPTY_PARENTS_REF = 0x01,
1026 REMOVE_EMPTY_PARENTS_REFLOG = 0x02
1027 };
1028
1029 /*
1030 * Remove empty parent directories associated with the specified
1031 * reference and/or its reflog, but spare [logs/]refs/ and immediate
1032 * subdirs. flags is a combination of REMOVE_EMPTY_PARENTS_REF and/or
1033 * REMOVE_EMPTY_PARENTS_REFLOG.
1034 */
1035 static void try_remove_empty_parents(struct files_ref_store *refs,
1036 const char *refname,
1037 unsigned int flags)
1038 {
1039 struct strbuf buf = STRBUF_INIT;
1040 struct strbuf sb = STRBUF_INIT;
1041 char *p, *q;
1042 int i;
1043
1044 strbuf_addstr(&buf, refname);
1045 p = buf.buf;
1046 for (i = 0; i < 2; i++) { /* refs/{heads,tags,...}/ */
1047 while (*p && *p != '/')
1048 p++;
1049 /* tolerate duplicate slashes; see check_refname_format() */
1050 while (*p == '/')
1051 p++;
1052 }
1053 q = buf.buf + buf.len;
1054 while (flags & (REMOVE_EMPTY_PARENTS_REF | REMOVE_EMPTY_PARENTS_REFLOG)) {
1055 while (q > p && *q != '/')
1056 q--;
1057 while (q > p && *(q-1) == '/')
1058 q--;
1059 if (q == p)
1060 break;
1061 strbuf_setlen(&buf, q - buf.buf);
1062
1063 strbuf_reset(&sb);
1064 files_ref_path(refs, &sb, buf.buf);
1065 if ((flags & REMOVE_EMPTY_PARENTS_REF) && rmdir(sb.buf))
1066 flags &= ~REMOVE_EMPTY_PARENTS_REF;
1067
1068 strbuf_reset(&sb);
1069 files_reflog_path(refs, &sb, buf.buf);
1070 if ((flags & REMOVE_EMPTY_PARENTS_REFLOG) && rmdir(sb.buf))
1071 flags &= ~REMOVE_EMPTY_PARENTS_REFLOG;
1072 }
1073 strbuf_release(&buf);
1074 strbuf_release(&sb);
1075 }
1076
1077 /* make sure nobody touched the ref, and unlink */
1078 static void prune_ref(struct files_ref_store *refs, struct ref_to_prune *r)
1079 {
1080 struct ref_transaction *transaction;
1081 struct strbuf err = STRBUF_INIT;
1082 int ret = -1;
1083
1084 if (check_refname_format(r->name, 0))
1085 return;
1086
1087 transaction = ref_store_transaction_begin(&refs->base, &err);
1088 if (!transaction)
1089 goto cleanup;
1090 ref_transaction_add_update(
1091 transaction, r->name,
1092 REF_NO_DEREF | REF_HAVE_NEW | REF_HAVE_OLD | REF_IS_PRUNING,
1093 &null_oid, &r->oid, NULL);
1094 if (ref_transaction_commit(transaction, &err))
1095 goto cleanup;
1096
1097 ret = 0;
1098
1099 cleanup:
1100 if (ret)
1101 error("%s", err.buf);
1102 strbuf_release(&err);
1103 ref_transaction_free(transaction);
1104 return;
1105 }
1106
1107 /*
1108 * Prune the loose versions of the references in the linked list
1109 * `*refs_to_prune`, freeing the entries in the list as we go.
1110 */
1111 static void prune_refs(struct files_ref_store *refs, struct ref_to_prune **refs_to_prune)
1112 {
1113 while (*refs_to_prune) {
1114 struct ref_to_prune *r = *refs_to_prune;
1115 *refs_to_prune = r->next;
1116 prune_ref(refs, r);
1117 free(r);
1118 }
1119 }
1120
1121 /*
1122 * Return true if the specified reference should be packed.
1123 */
1124 static int should_pack_ref(const char *refname,
1125 const struct object_id *oid, unsigned int ref_flags,
1126 unsigned int pack_flags)
1127 {
1128 /* Do not pack per-worktree refs: */
1129 if (ref_type(refname) != REF_TYPE_NORMAL)
1130 return 0;
1131
1132 /* Do not pack non-tags unless PACK_REFS_ALL is set: */
1133 if (!(pack_flags & PACK_REFS_ALL) && !starts_with(refname, "refs/tags/"))
1134 return 0;
1135
1136 /* Do not pack symbolic refs: */
1137 if (ref_flags & REF_ISSYMREF)
1138 return 0;
1139
1140 /* Do not pack broken refs: */
1141 if (!ref_resolves_to_object(refname, oid, ref_flags))
1142 return 0;
1143
1144 return 1;
1145 }
1146
1147 static int files_pack_refs(struct ref_store *ref_store, unsigned int flags)
1148 {
1149 struct files_ref_store *refs =
1150 files_downcast(ref_store, REF_STORE_WRITE | REF_STORE_ODB,
1151 "pack_refs");
1152 struct ref_iterator *iter;
1153 int ok;
1154 struct ref_to_prune *refs_to_prune = NULL;
1155 struct strbuf err = STRBUF_INIT;
1156 struct ref_transaction *transaction;
1157
1158 transaction = ref_store_transaction_begin(refs->packed_ref_store, &err);
1159 if (!transaction)
1160 return -1;
1161
1162 packed_refs_lock(refs->packed_ref_store, LOCK_DIE_ON_ERROR, &err);
1163
1164 iter = cache_ref_iterator_begin(get_loose_ref_cache(refs), NULL, 0);
1165 while ((ok = ref_iterator_advance(iter)) == ITER_OK) {
1166 /*
1167 * If the loose reference can be packed, add an entry
1168 * in the packed ref cache. If the reference should be
1169 * pruned, also add it to refs_to_prune.
1170 */
1171 if (!should_pack_ref(iter->refname, iter->oid, iter->flags,
1172 flags))
1173 continue;
1174
1175 /*
1176 * Add a reference creation for this reference to the
1177 * packed-refs transaction:
1178 */
1179 if (ref_transaction_update(transaction, iter->refname,
1180 iter->oid, NULL,
1181 REF_NO_DEREF, NULL, &err))
1182 die("failure preparing to create packed reference %s: %s",
1183 iter->refname, err.buf);
1184
1185 /* Schedule the loose reference for pruning if requested. */
1186 if ((flags & PACK_REFS_PRUNE)) {
1187 struct ref_to_prune *n;
1188 FLEX_ALLOC_STR(n, name, iter->refname);
1189 oidcpy(&n->oid, iter->oid);
1190 n->next = refs_to_prune;
1191 refs_to_prune = n;
1192 }
1193 }
1194 if (ok != ITER_DONE)
1195 die("error while iterating over references");
1196
1197 if (ref_transaction_commit(transaction, &err))
1198 die("unable to write new packed-refs: %s", err.buf);
1199
1200 ref_transaction_free(transaction);
1201
1202 packed_refs_unlock(refs->packed_ref_store);
1203
1204 prune_refs(refs, &refs_to_prune);
1205 strbuf_release(&err);
1206 return 0;
1207 }
1208
1209 static int files_delete_refs(struct ref_store *ref_store, const char *msg,
1210 struct string_list *refnames, unsigned int flags)
1211 {
1212 struct files_ref_store *refs =
1213 files_downcast(ref_store, REF_STORE_WRITE, "delete_refs");
1214 struct strbuf err = STRBUF_INIT;
1215 int i, result = 0;
1216
1217 if (!refnames->nr)
1218 return 0;
1219
1220 if (packed_refs_lock(refs->packed_ref_store, 0, &err))
1221 goto error;
1222
1223 if (refs_delete_refs(refs->packed_ref_store, msg, refnames, flags)) {
1224 packed_refs_unlock(refs->packed_ref_store);
1225 goto error;
1226 }
1227
1228 packed_refs_unlock(refs->packed_ref_store);
1229
1230 for (i = 0; i < refnames->nr; i++) {
1231 const char *refname = refnames->items[i].string;
1232
1233 if (refs_delete_ref(&refs->base, msg, refname, NULL, flags))
1234 result |= error(_("could not remove reference %s"), refname);
1235 }
1236
1237 strbuf_release(&err);
1238 return result;
1239
1240 error:
1241 /*
1242 * If we failed to rewrite the packed-refs file, then it is
1243 * unsafe to try to remove loose refs, because doing so might
1244 * expose an obsolete packed value for a reference that might
1245 * even point at an object that has been garbage collected.
1246 */
1247 if (refnames->nr == 1)
1248 error(_("could not delete reference %s: %s"),
1249 refnames->items[0].string, err.buf);
1250 else
1251 error(_("could not delete references: %s"), err.buf);
1252
1253 strbuf_release(&err);
1254 return -1;
1255 }
1256
1257 /*
1258 * People using contrib's git-new-workdir have .git/logs/refs ->
1259 * /some/other/path/.git/logs/refs, and that may live on another device.
1260 *
1261 * IOW, to avoid cross device rename errors, the temporary renamed log must
1262 * live into logs/refs.
1263 */
1264 #define TMP_RENAMED_LOG "refs/.tmp-renamed-log"
1265
1266 struct rename_cb {
1267 const char *tmp_renamed_log;
1268 int true_errno;
1269 };
1270
1271 static int rename_tmp_log_callback(const char *path, void *cb_data)
1272 {
1273 struct rename_cb *cb = cb_data;
1274
1275 if (rename(cb->tmp_renamed_log, path)) {
1276 /*
1277 * rename(a, b) when b is an existing directory ought
1278 * to result in ISDIR, but Solaris 5.8 gives ENOTDIR.
1279 * Sheesh. Record the true errno for error reporting,
1280 * but report EISDIR to raceproof_create_file() so
1281 * that it knows to retry.
1282 */
1283 cb->true_errno = errno;
1284 if (errno == ENOTDIR)
1285 errno = EISDIR;
1286 return -1;
1287 } else {
1288 return 0;
1289 }
1290 }
1291
1292 static int rename_tmp_log(struct files_ref_store *refs, const char *newrefname)
1293 {
1294 struct strbuf path = STRBUF_INIT;
1295 struct strbuf tmp = STRBUF_INIT;
1296 struct rename_cb cb;
1297 int ret;
1298
1299 files_reflog_path(refs, &path, newrefname);
1300 files_reflog_path(refs, &tmp, TMP_RENAMED_LOG);
1301 cb.tmp_renamed_log = tmp.buf;
1302 ret = raceproof_create_file(path.buf, rename_tmp_log_callback, &cb);
1303 if (ret) {
1304 if (errno == EISDIR)
1305 error("directory not empty: %s", path.buf);
1306 else
1307 error("unable to move logfile %s to %s: %s",
1308 tmp.buf, path.buf,
1309 strerror(cb.true_errno));
1310 }
1311
1312 strbuf_release(&path);
1313 strbuf_release(&tmp);
1314 return ret;
1315 }
1316
1317 static int write_ref_to_lockfile(struct ref_lock *lock,
1318 const struct object_id *oid, struct strbuf *err);
1319 static int commit_ref_update(struct files_ref_store *refs,
1320 struct ref_lock *lock,
1321 const struct object_id *oid, const char *logmsg,
1322 struct strbuf *err);
1323
1324 static int files_copy_or_rename_ref(struct ref_store *ref_store,
1325 const char *oldrefname, const char *newrefname,
1326 const char *logmsg, int copy)
1327 {
1328 struct files_ref_store *refs =
1329 files_downcast(ref_store, REF_STORE_WRITE, "rename_ref");
1330 struct object_id oid, orig_oid;
1331 int flag = 0, logmoved = 0;
1332 struct ref_lock *lock;
1333 struct stat loginfo;
1334 struct strbuf sb_oldref = STRBUF_INIT;
1335 struct strbuf sb_newref = STRBUF_INIT;
1336 struct strbuf tmp_renamed_log = STRBUF_INIT;
1337 int log, ret;
1338 struct strbuf err = STRBUF_INIT;
1339
1340 files_reflog_path(refs, &sb_oldref, oldrefname);
1341 files_reflog_path(refs, &sb_newref, newrefname);
1342 files_reflog_path(refs, &tmp_renamed_log, TMP_RENAMED_LOG);
1343
1344 log = !lstat(sb_oldref.buf, &loginfo);
1345 if (log && S_ISLNK(loginfo.st_mode)) {
1346 ret = error("reflog for %s is a symlink", oldrefname);
1347 goto out;
1348 }
1349
1350 if (!refs_resolve_ref_unsafe(&refs->base, oldrefname,
1351 RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
1352 &orig_oid, &flag)) {
1353 ret = error("refname %s not found", oldrefname);
1354 goto out;
1355 }
1356
1357 if (flag & REF_ISSYMREF) {
1358 if (copy)
1359 ret = error("refname %s is a symbolic ref, copying it is not supported",
1360 oldrefname);
1361 else
1362 ret = error("refname %s is a symbolic ref, renaming it is not supported",
1363 oldrefname);
1364 goto out;
1365 }
1366 if (!refs_rename_ref_available(&refs->base, oldrefname, newrefname)) {
1367 ret = 1;
1368 goto out;
1369 }
1370
1371 if (!copy && log && rename(sb_oldref.buf, tmp_renamed_log.buf)) {
1372 ret = error("unable to move logfile logs/%s to logs/"TMP_RENAMED_LOG": %s",
1373 oldrefname, strerror(errno));
1374 goto out;
1375 }
1376
1377 if (copy && log && copy_file(tmp_renamed_log.buf, sb_oldref.buf, 0644)) {
1378 ret = error("unable to copy logfile logs/%s to logs/"TMP_RENAMED_LOG": %s",
1379 oldrefname, strerror(errno));
1380 goto out;
1381 }
1382
1383 if (!copy && refs_delete_ref(&refs->base, logmsg, oldrefname,
1384 &orig_oid, REF_NO_DEREF)) {
1385 error("unable to delete old %s", oldrefname);
1386 goto rollback;
1387 }
1388
1389 /*
1390 * Since we are doing a shallow lookup, oid is not the
1391 * correct value to pass to delete_ref as old_oid. But that
1392 * doesn't matter, because an old_oid check wouldn't add to
1393 * the safety anyway; we want to delete the reference whatever
1394 * its current value.
1395 */
1396 if (!copy && !refs_read_ref_full(&refs->base, newrefname,
1397 RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
1398 &oid, NULL) &&
1399 refs_delete_ref(&refs->base, NULL, newrefname,
1400 NULL, REF_NO_DEREF)) {
1401 if (errno == EISDIR) {
1402 struct strbuf path = STRBUF_INIT;
1403 int result;
1404
1405 files_ref_path(refs, &path, newrefname);
1406 result = remove_empty_directories(&path);
1407 strbuf_release(&path);
1408
1409 if (result) {
1410 error("Directory not empty: %s", newrefname);
1411 goto rollback;
1412 }
1413 } else {
1414 error("unable to delete existing %s", newrefname);
1415 goto rollback;
1416 }
1417 }
1418
1419 if (log && rename_tmp_log(refs, newrefname))
1420 goto rollback;
1421
1422 logmoved = log;
1423
1424 lock = lock_ref_oid_basic(refs, newrefname, NULL, NULL, NULL,
1425 REF_NO_DEREF, NULL, &err);
1426 if (!lock) {
1427 if (copy)
1428 error("unable to copy '%s' to '%s': %s", oldrefname, newrefname, err.buf);
1429 else
1430 error("unable to rename '%s' to '%s': %s", oldrefname, newrefname, err.buf);
1431 strbuf_release(&err);
1432 goto rollback;
1433 }
1434 oidcpy(&lock->old_oid, &orig_oid);
1435
1436 if (write_ref_to_lockfile(lock, &orig_oid, &err) ||
1437 commit_ref_update(refs, lock, &orig_oid, logmsg, &err)) {
1438 error("unable to write current sha1 into %s: %s", newrefname, err.buf);
1439 strbuf_release(&err);
1440 goto rollback;
1441 }
1442
1443 ret = 0;
1444 goto out;
1445
1446 rollback:
1447 lock = lock_ref_oid_basic(refs, oldrefname, NULL, NULL, NULL,
1448 REF_NO_DEREF, NULL, &err);
1449 if (!lock) {
1450 error("unable to lock %s for rollback: %s", oldrefname, err.buf);
1451 strbuf_release(&err);
1452 goto rollbacklog;
1453 }
1454
1455 flag = log_all_ref_updates;
1456 log_all_ref_updates = LOG_REFS_NONE;
1457 if (write_ref_to_lockfile(lock, &orig_oid, &err) ||
1458 commit_ref_update(refs, lock, &orig_oid, NULL, &err)) {
1459 error("unable to write current sha1 into %s: %s", oldrefname, err.buf);
1460 strbuf_release(&err);
1461 }
1462 log_all_ref_updates = flag;
1463
1464 rollbacklog:
1465 if (logmoved && rename(sb_newref.buf, sb_oldref.buf))
1466 error("unable to restore logfile %s from %s: %s",
1467 oldrefname, newrefname, strerror(errno));
1468 if (!logmoved && log &&
1469 rename(tmp_renamed_log.buf, sb_oldref.buf))
1470 error("unable to restore logfile %s from logs/"TMP_RENAMED_LOG": %s",
1471 oldrefname, strerror(errno));
1472 ret = 1;
1473 out:
1474 strbuf_release(&sb_newref);
1475 strbuf_release(&sb_oldref);
1476 strbuf_release(&tmp_renamed_log);
1477
1478 return ret;
1479 }
1480
1481 static int files_rename_ref(struct ref_store *ref_store,
1482 const char *oldrefname, const char *newrefname,
1483 const char *logmsg)
1484 {
1485 return files_copy_or_rename_ref(ref_store, oldrefname,
1486 newrefname, logmsg, 0);
1487 }
1488
1489 static int files_copy_ref(struct ref_store *ref_store,
1490 const char *oldrefname, const char *newrefname,
1491 const char *logmsg)
1492 {
1493 return files_copy_or_rename_ref(ref_store, oldrefname,
1494 newrefname, logmsg, 1);
1495 }
1496
1497 static int close_ref_gently(struct ref_lock *lock)
1498 {
1499 if (close_lock_file_gently(&lock->lk))
1500 return -1;
1501 return 0;
1502 }
1503
1504 static int commit_ref(struct ref_lock *lock)
1505 {
1506 char *path = get_locked_file_path(&lock->lk);
1507 struct stat st;
1508
1509 if (!lstat(path, &st) && S_ISDIR(st.st_mode)) {
1510 /*
1511 * There is a directory at the path we want to rename
1512 * the lockfile to. Hopefully it is empty; try to
1513 * delete it.
1514 */
1515 size_t len = strlen(path);
1516 struct strbuf sb_path = STRBUF_INIT;
1517
1518 strbuf_attach(&sb_path, path, len, len);
1519
1520 /*
1521 * If this fails, commit_lock_file() will also fail
1522 * and will report the problem.
1523 */
1524 remove_empty_directories(&sb_path);
1525 strbuf_release(&sb_path);
1526 } else {
1527 free(path);
1528 }
1529
1530 if (commit_lock_file(&lock->lk))
1531 return -1;
1532 return 0;
1533 }
1534
1535 static int open_or_create_logfile(const char *path, void *cb)
1536 {
1537 int *fd = cb;
1538
1539 *fd = open(path, O_APPEND | O_WRONLY | O_CREAT, 0666);
1540 return (*fd < 0) ? -1 : 0;
1541 }
1542
1543 /*
1544 * Create a reflog for a ref. If force_create = 0, only create the
1545 * reflog for certain refs (those for which should_autocreate_reflog
1546 * returns non-zero). Otherwise, create it regardless of the reference
1547 * name. If the logfile already existed or was created, return 0 and
1548 * set *logfd to the file descriptor opened for appending to the file.
1549 * If no logfile exists and we decided not to create one, return 0 and
1550 * set *logfd to -1. On failure, fill in *err, set *logfd to -1, and
1551 * return -1.
1552 */
1553 static int log_ref_setup(struct files_ref_store *refs,
1554 const char *refname, int force_create,
1555 int *logfd, struct strbuf *err)
1556 {
1557 struct strbuf logfile_sb = STRBUF_INIT;
1558 char *logfile;
1559
1560 files_reflog_path(refs, &logfile_sb, refname);
1561 logfile = strbuf_detach(&logfile_sb, NULL);
1562
1563 if (force_create || should_autocreate_reflog(refname)) {
1564 if (raceproof_create_file(logfile, open_or_create_logfile, logfd)) {
1565 if (errno == ENOENT)
1566 strbuf_addf(err, "unable to create directory for '%s': "
1567 "%s", logfile, strerror(errno));
1568 else if (errno == EISDIR)
1569 strbuf_addf(err, "there are still logs under '%s'",
1570 logfile);
1571 else
1572 strbuf_addf(err, "unable to append to '%s': %s",
1573 logfile, strerror(errno));
1574
1575 goto error;
1576 }
1577 } else {
1578 *logfd = open(logfile, O_APPEND | O_WRONLY, 0666);
1579 if (*logfd < 0) {
1580 if (errno == ENOENT || errno == EISDIR) {
1581 /*
1582 * The logfile doesn't already exist,
1583 * but that is not an error; it only
1584 * means that we won't write log
1585 * entries to it.
1586 */
1587 ;
1588 } else {
1589 strbuf_addf(err, "unable to append to '%s': %s",
1590 logfile, strerror(errno));
1591 goto error;
1592 }
1593 }
1594 }
1595
1596 if (*logfd >= 0)
1597 adjust_shared_perm(logfile);
1598
1599 free(logfile);
1600 return 0;
1601
1602 error:
1603 free(logfile);
1604 return -1;
1605 }
1606
1607 static int files_create_reflog(struct ref_store *ref_store,
1608 const char *refname, int force_create,
1609 struct strbuf *err)
1610 {
1611 struct files_ref_store *refs =
1612 files_downcast(ref_store, REF_STORE_WRITE, "create_reflog");
1613 int fd;
1614
1615 if (log_ref_setup(refs, refname, force_create, &fd, err))
1616 return -1;
1617
1618 if (fd >= 0)
1619 close(fd);
1620
1621 return 0;
1622 }
1623
1624 static int log_ref_write_fd(int fd, const struct object_id *old_oid,
1625 const struct object_id *new_oid,
1626 const char *committer, const char *msg)
1627 {
1628 struct strbuf sb = STRBUF_INIT;
1629 int ret = 0;
1630
1631 strbuf_addf(&sb, "%s %s %s", oid_to_hex(old_oid), oid_to_hex(new_oid), committer);
1632 if (msg && *msg)
1633 copy_reflog_msg(&sb, msg);
1634 strbuf_addch(&sb, '\n');
1635 if (write_in_full(fd, sb.buf, sb.len) < 0)
1636 ret = -1;
1637 strbuf_release(&sb);
1638 return ret;
1639 }
1640
1641 static int files_log_ref_write(struct files_ref_store *refs,
1642 const char *refname, const struct object_id *old_oid,
1643 const struct object_id *new_oid, const char *msg,
1644 int flags, struct strbuf *err)
1645 {
1646 int logfd, result;
1647
1648 if (log_all_ref_updates == LOG_REFS_UNSET)
1649 log_all_ref_updates = is_bare_repository() ? LOG_REFS_NONE : LOG_REFS_NORMAL;
1650
1651 result = log_ref_setup(refs, refname,
1652 flags & REF_FORCE_CREATE_REFLOG,
1653 &logfd, err);
1654
1655 if (result)
1656 return result;
1657
1658 if (logfd < 0)
1659 return 0;
1660 result = log_ref_write_fd(logfd, old_oid, new_oid,
1661 git_committer_info(0), msg);
1662 if (result) {
1663 struct strbuf sb = STRBUF_INIT;
1664 int save_errno = errno;
1665
1666 files_reflog_path(refs, &sb, refname);
1667 strbuf_addf(err, "unable to append to '%s': %s",
1668 sb.buf, strerror(save_errno));
1669 strbuf_release(&sb);
1670 close(logfd);
1671 return -1;
1672 }
1673 if (close(logfd)) {
1674 struct strbuf sb = STRBUF_INIT;
1675 int save_errno = errno;
1676
1677 files_reflog_path(refs, &sb, refname);
1678 strbuf_addf(err, "unable to append to '%s': %s",
1679 sb.buf, strerror(save_errno));
1680 strbuf_release(&sb);
1681 return -1;
1682 }
1683 return 0;
1684 }
1685
1686 /*
1687 * Write oid into the open lockfile, then close the lockfile. On
1688 * errors, rollback the lockfile, fill in *err and return -1.
1689 */
1690 static int write_ref_to_lockfile(struct ref_lock *lock,
1691 const struct object_id *oid, struct strbuf *err)
1692 {
1693 static char term = '\n';
1694 struct object *o;
1695 int fd;
1696
1697 o = parse_object(the_repository, oid);
1698 if (!o) {
1699 strbuf_addf(err,
1700 "trying to write ref '%s' with nonexistent object %s",
1701 lock->ref_name, oid_to_hex(oid));
1702 unlock_ref(lock);
1703 return -1;
1704 }
1705 if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
1706 strbuf_addf(err,
1707 "trying to write non-commit object %s to branch '%s'",
1708 oid_to_hex(oid), lock->ref_name);
1709 unlock_ref(lock);
1710 return -1;
1711 }
1712 fd = get_lock_file_fd(&lock->lk);
1713 if (write_in_full(fd, oid_to_hex(oid), the_hash_algo->hexsz) < 0 ||
1714 write_in_full(fd, &term, 1) < 0 ||
1715 close_ref_gently(lock) < 0) {
1716 strbuf_addf(err,
1717 "couldn't write '%s'", get_lock_file_path(&lock->lk));
1718 unlock_ref(lock);
1719 return -1;
1720 }
1721 return 0;
1722 }
1723
1724 /*
1725 * Commit a change to a loose reference that has already been written
1726 * to the loose reference lockfile. Also update the reflogs if
1727 * necessary, using the specified lockmsg (which can be NULL).
1728 */
1729 static int commit_ref_update(struct files_ref_store *refs,
1730 struct ref_lock *lock,
1731 const struct object_id *oid, const char *logmsg,
1732 struct strbuf *err)
1733 {
1734 files_assert_main_repository(refs, "commit_ref_update");
1735
1736 clear_loose_ref_cache(refs);
1737 if (files_log_ref_write(refs, lock->ref_name,
1738 &lock->old_oid, oid,
1739 logmsg, 0, err)) {
1740 char *old_msg = strbuf_detach(err, NULL);
1741 strbuf_addf(err, "cannot update the ref '%s': %s",
1742 lock->ref_name, old_msg);
1743 free(old_msg);
1744 unlock_ref(lock);
1745 return -1;
1746 }
1747
1748 if (strcmp(lock->ref_name, "HEAD") != 0) {
1749 /*
1750 * Special hack: If a branch is updated directly and HEAD
1751 * points to it (may happen on the remote side of a push
1752 * for example) then logically the HEAD reflog should be
1753 * updated too.
1754 * A generic solution implies reverse symref information,
1755 * but finding all symrefs pointing to the given branch
1756 * would be rather costly for this rare event (the direct
1757 * update of a branch) to be worth it. So let's cheat and
1758 * check with HEAD only which should cover 99% of all usage
1759 * scenarios (even 100% of the default ones).
1760 */
1761 int head_flag;
1762 const char *head_ref;
1763
1764 head_ref = refs_resolve_ref_unsafe(&refs->base, "HEAD",
1765 RESOLVE_REF_READING,
1766 NULL, &head_flag);
1767 if (head_ref && (head_flag & REF_ISSYMREF) &&
1768 !strcmp(head_ref, lock->ref_name)) {
1769 struct strbuf log_err = STRBUF_INIT;
1770 if (files_log_ref_write(refs, "HEAD",
1771 &lock->old_oid, oid,
1772 logmsg, 0, &log_err)) {
1773 error("%s", log_err.buf);
1774 strbuf_release(&log_err);
1775 }
1776 }
1777 }
1778
1779 if (commit_ref(lock)) {
1780 strbuf_addf(err, "couldn't set '%s'", lock->ref_name);
1781 unlock_ref(lock);
1782 return -1;
1783 }
1784
1785 unlock_ref(lock);
1786 return 0;
1787 }
1788
1789 static int create_ref_symlink(struct ref_lock *lock, const char *target)
1790 {
1791 int ret = -1;
1792 #ifndef NO_SYMLINK_HEAD
1793 char *ref_path = get_locked_file_path(&lock->lk);
1794 unlink(ref_path);
1795 ret = symlink(target, ref_path);
1796 free(ref_path);
1797
1798 if (ret)
1799 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
1800 #endif
1801 return ret;
1802 }
1803
1804 static void update_symref_reflog(struct files_ref_store *refs,
1805 struct ref_lock *lock, const char *refname,
1806 const char *target, const char *logmsg)
1807 {
1808 struct strbuf err = STRBUF_INIT;
1809 struct object_id new_oid;
1810 if (logmsg &&
1811 !refs_read_ref_full(&refs->base, target,
1812 RESOLVE_REF_READING, &new_oid, NULL) &&
1813 files_log_ref_write(refs, refname, &lock->old_oid,
1814 &new_oid, logmsg, 0, &err)) {
1815 error("%s", err.buf);
1816 strbuf_release(&err);
1817 }
1818 }
1819
1820 static int create_symref_locked(struct files_ref_store *refs,
1821 struct ref_lock *lock, const char *refname,
1822 const char *target, const char *logmsg)
1823 {
1824 if (prefer_symlink_refs && !create_ref_symlink(lock, target)) {
1825 update_symref_reflog(refs, lock, refname, target, logmsg);
1826 return 0;
1827 }
1828
1829 if (!fdopen_lock_file(&lock->lk, "w"))
1830 return error("unable to fdopen %s: %s",
1831 lock->lk.tempfile->filename.buf, strerror(errno));
1832
1833 update_symref_reflog(refs, lock, refname, target, logmsg);
1834
1835 /* no error check; commit_ref will check ferror */
1836 fprintf(lock->lk.tempfile->fp, "ref: %s\n", target);
1837 if (commit_ref(lock) < 0)
1838 return error("unable to write symref for %s: %s", refname,
1839 strerror(errno));
1840 return 0;
1841 }
1842
1843 static int files_create_symref(struct ref_store *ref_store,
1844 const char *refname, const char *target,
1845 const char *logmsg)
1846 {
1847 struct files_ref_store *refs =
1848 files_downcast(ref_store, REF_STORE_WRITE, "create_symref");
1849 struct strbuf err = STRBUF_INIT;
1850 struct ref_lock *lock;
1851 int ret;
1852
1853 lock = lock_ref_oid_basic(refs, refname, NULL,
1854 NULL, NULL, REF_NO_DEREF, NULL,
1855 &err);
1856 if (!lock) {
1857 error("%s", err.buf);
1858 strbuf_release(&err);
1859 return -1;
1860 }
1861
1862 ret = create_symref_locked(refs, lock, refname, target, logmsg);
1863 unlock_ref(lock);
1864 return ret;
1865 }
1866
1867 static int files_reflog_exists(struct ref_store *ref_store,
1868 const char *refname)
1869 {
1870 struct files_ref_store *refs =
1871 files_downcast(ref_store, REF_STORE_READ, "reflog_exists");
1872 struct strbuf sb = STRBUF_INIT;
1873 struct stat st;
1874 int ret;
1875
1876 files_reflog_path(refs, &sb, refname);
1877 ret = !lstat(sb.buf, &st) && S_ISREG(st.st_mode);
1878 strbuf_release(&sb);
1879 return ret;
1880 }
1881
1882 static int files_delete_reflog(struct ref_store *ref_store,
1883 const char *refname)
1884 {
1885 struct files_ref_store *refs =
1886 files_downcast(ref_store, REF_STORE_WRITE, "delete_reflog");
1887 struct strbuf sb = STRBUF_INIT;
1888 int ret;
1889
1890 files_reflog_path(refs, &sb, refname);
1891 ret = remove_path(sb.buf);
1892 strbuf_release(&sb);
1893 return ret;
1894 }
1895
1896 static int show_one_reflog_ent(struct strbuf *sb, each_reflog_ent_fn fn, void *cb_data)
1897 {
1898 struct object_id ooid, noid;
1899 char *email_end, *message;
1900 timestamp_t timestamp;
1901 int tz;
1902 const char *p = sb->buf;
1903
1904 /* old SP new SP name <email> SP time TAB msg LF */
1905 if (!sb->len || sb->buf[sb->len - 1] != '\n' ||
1906 parse_oid_hex(p, &ooid, &p) || *p++ != ' ' ||
1907 parse_oid_hex(p, &noid, &p) || *p++ != ' ' ||
1908 !(email_end = strchr(p, '>')) ||
1909 email_end[1] != ' ' ||
1910 !(timestamp = parse_timestamp(email_end + 2, &message, 10)) ||
1911 !message || message[0] != ' ' ||
1912 (message[1] != '+' && message[1] != '-') ||
1913 !isdigit(message[2]) || !isdigit(message[3]) ||
1914 !isdigit(message[4]) || !isdigit(message[5]))
1915 return 0; /* corrupt? */
1916 email_end[1] = '\0';
1917 tz = strtol(message + 1, NULL, 10);
1918 if (message[6] != '\t')
1919 message += 6;
1920 else
1921 message += 7;
1922 return fn(&ooid, &noid, p, timestamp, tz, message, cb_data);
1923 }
1924
1925 static char *find_beginning_of_line(char *bob, char *scan)
1926 {
1927 while (bob < scan && *(--scan) != '\n')
1928 ; /* keep scanning backwards */
1929 /*
1930 * Return either beginning of the buffer, or LF at the end of
1931 * the previous line.
1932 */
1933 return scan;
1934 }
1935
1936 static int files_for_each_reflog_ent_reverse(struct ref_store *ref_store,
1937 const char *refname,
1938 each_reflog_ent_fn fn,
1939 void *cb_data)
1940 {
1941 struct files_ref_store *refs =
1942 files_downcast(ref_store, REF_STORE_READ,
1943 "for_each_reflog_ent_reverse");
1944 struct strbuf sb = STRBUF_INIT;
1945 FILE *logfp;
1946 long pos;
1947 int ret = 0, at_tail = 1;
1948
1949 files_reflog_path(refs, &sb, refname);
1950 logfp = fopen(sb.buf, "r");
1951 strbuf_release(&sb);
1952 if (!logfp)
1953 return -1;
1954
1955 /* Jump to the end */
1956 if (fseek(logfp, 0, SEEK_END) < 0)
1957 ret = error("cannot seek back reflog for %s: %s",
1958 refname, strerror(errno));
1959 pos = ftell(logfp);
1960 while (!ret && 0 < pos) {
1961 int cnt;
1962 size_t nread;
1963 char buf[BUFSIZ];
1964 char *endp, *scanp;
1965
1966 /* Fill next block from the end */
1967 cnt = (sizeof(buf) < pos) ? sizeof(buf) : pos;
1968 if (fseek(logfp, pos - cnt, SEEK_SET)) {
1969 ret = error("cannot seek back reflog for %s: %s",
1970 refname, strerror(errno));
1971 break;
1972 }
1973 nread = fread(buf, cnt, 1, logfp);
1974 if (nread != 1) {
1975 ret = error("cannot read %d bytes from reflog for %s: %s",
1976 cnt, refname, strerror(errno));
1977 break;
1978 }
1979 pos -= cnt;
1980
1981 scanp = endp = buf + cnt;
1982 if (at_tail && scanp[-1] == '\n')
1983 /* Looking at the final LF at the end of the file */
1984 scanp--;
1985 at_tail = 0;
1986
1987 while (buf < scanp) {
1988 /*
1989 * terminating LF of the previous line, or the beginning
1990 * of the buffer.
1991 */
1992 char *bp;
1993
1994 bp = find_beginning_of_line(buf, scanp);
1995
1996 if (*bp == '\n') {
1997 /*
1998 * The newline is the end of the previous line,
1999 * so we know we have complete line starting
2000 * at (bp + 1). Prefix it onto any prior data
2001 * we collected for the line and process it.
2002 */
2003 strbuf_splice(&sb, 0, 0, bp + 1, endp - (bp + 1));
2004 scanp = bp;
2005 endp = bp + 1;
2006 ret = show_one_reflog_ent(&sb, fn, cb_data);
2007 strbuf_reset(&sb);
2008 if (ret)
2009 break;
2010 } else if (!pos) {
2011 /*
2012 * We are at the start of the buffer, and the
2013 * start of the file; there is no previous
2014 * line, and we have everything for this one.
2015 * Process it, and we can end the loop.
2016 */
2017 strbuf_splice(&sb, 0, 0, buf, endp - buf);
2018 ret = show_one_reflog_ent(&sb, fn, cb_data);
2019 strbuf_reset(&sb);
2020 break;
2021 }
2022
2023 if (bp == buf) {
2024 /*
2025 * We are at the start of the buffer, and there
2026 * is more file to read backwards. Which means
2027 * we are in the middle of a line. Note that we
2028 * may get here even if *bp was a newline; that
2029 * just means we are at the exact end of the
2030 * previous line, rather than some spot in the
2031 * middle.
2032 *
2033 * Save away what we have to be combined with
2034 * the data from the next read.
2035 */
2036 strbuf_splice(&sb, 0, 0, buf, endp - buf);
2037 break;
2038 }
2039 }
2040
2041 }
2042 if (!ret && sb.len)
2043 BUG("reverse reflog parser had leftover data");
2044
2045 fclose(logfp);
2046 strbuf_release(&sb);
2047 return ret;
2048 }
2049
2050 static int files_for_each_reflog_ent(struct ref_store *ref_store,
2051 const char *refname,
2052 each_reflog_ent_fn fn, void *cb_data)
2053 {
2054 struct files_ref_store *refs =
2055 files_downcast(ref_store, REF_STORE_READ,
2056 "for_each_reflog_ent");
2057 FILE *logfp;
2058 struct strbuf sb = STRBUF_INIT;
2059 int ret = 0;
2060
2061 files_reflog_path(refs, &sb, refname);
2062 logfp = fopen(sb.buf, "r");
2063 strbuf_release(&sb);
2064 if (!logfp)
2065 return -1;
2066
2067 while (!ret && !strbuf_getwholeline(&sb, logfp, '\n'))
2068 ret = show_one_reflog_ent(&sb, fn, cb_data);
2069 fclose(logfp);
2070 strbuf_release(&sb);
2071 return ret;
2072 }
2073
2074 struct files_reflog_iterator {
2075 struct ref_iterator base;
2076
2077 struct ref_store *ref_store;
2078 struct dir_iterator *dir_iterator;
2079 struct object_id oid;
2080 };
2081
2082 static int files_reflog_iterator_advance(struct ref_iterator *ref_iterator)
2083 {
2084 struct files_reflog_iterator *iter =
2085 (struct files_reflog_iterator *)ref_iterator;
2086 struct dir_iterator *diter = iter->dir_iterator;
2087 int ok;
2088
2089 while ((ok = dir_iterator_advance(diter)) == ITER_OK) {
2090 int flags;
2091
2092 if (!S_ISREG(diter->st.st_mode))
2093 continue;
2094 if (diter->basename[0] == '.')
2095 continue;
2096 if (ends_with(diter->basename, ".lock"))
2097 continue;
2098
2099 if (refs_read_ref_full(iter->ref_store,
2100 diter->relative_path, 0,
2101 &iter->oid, &flags)) {
2102 error("bad ref for %s", diter->path.buf);
2103 continue;
2104 }
2105
2106 iter->base.refname = diter->relative_path;
2107 iter->base.oid = &iter->oid;
2108 iter->base.flags = flags;
2109 return ITER_OK;
2110 }
2111
2112 iter->dir_iterator = NULL;
2113 if (ref_iterator_abort(ref_iterator) == ITER_ERROR)
2114 ok = ITER_ERROR;
2115 return ok;
2116 }
2117
2118 static int files_reflog_iterator_peel(struct ref_iterator *ref_iterator,
2119 struct object_id *peeled)
2120 {
2121 BUG("ref_iterator_peel() called for reflog_iterator");
2122 }
2123
2124 static int files_reflog_iterator_abort(struct ref_iterator *ref_iterator)
2125 {
2126 struct files_reflog_iterator *iter =
2127 (struct files_reflog_iterator *)ref_iterator;
2128 int ok = ITER_DONE;
2129
2130 if (iter->dir_iterator)
2131 ok = dir_iterator_abort(iter->dir_iterator);
2132
2133 base_ref_iterator_free(ref_iterator);
2134 return ok;
2135 }
2136
2137 static struct ref_iterator_vtable files_reflog_iterator_vtable = {
2138 files_reflog_iterator_advance,
2139 files_reflog_iterator_peel,
2140 files_reflog_iterator_abort
2141 };
2142
2143 static struct ref_iterator *reflog_iterator_begin(struct ref_store *ref_store,
2144 const char *gitdir)
2145 {
2146 struct files_reflog_iterator *iter = xcalloc(1, sizeof(*iter));
2147 struct ref_iterator *ref_iterator = &iter->base;
2148 struct strbuf sb = STRBUF_INIT;
2149
2150 base_ref_iterator_init(ref_iterator, &files_reflog_iterator_vtable, 0);
2151 strbuf_addf(&sb, "%s/logs", gitdir);
2152 iter->dir_iterator = dir_iterator_begin(sb.buf);
2153 iter->ref_store = ref_store;
2154 strbuf_release(&sb);
2155
2156 return ref_iterator;
2157 }
2158
2159 static enum iterator_selection reflog_iterator_select(
2160 struct ref_iterator *iter_worktree,
2161 struct ref_iterator *iter_common,
2162 void *cb_data)
2163 {
2164 if (iter_worktree) {
2165 /*
2166 * We're a bit loose here. We probably should ignore
2167 * common refs if they are accidentally added as
2168 * per-worktree refs.
2169 */
2170 return ITER_SELECT_0;
2171 } else if (iter_common) {
2172 if (ref_type(iter_common->refname) == REF_TYPE_NORMAL)
2173 return ITER_SELECT_1;
2174
2175 /*
2176 * The main ref store may contain main worktree's
2177 * per-worktree refs, which should be ignored
2178 */
2179 return ITER_SKIP_1;
2180 } else
2181 return ITER_DONE;
2182 }
2183
2184 static struct ref_iterator *files_reflog_iterator_begin(struct ref_store *ref_store)
2185 {
2186 struct files_ref_store *refs =
2187 files_downcast(ref_store, REF_STORE_READ,
2188 "reflog_iterator_begin");
2189
2190 if (!strcmp(refs->gitdir, refs->gitcommondir)) {
2191 return reflog_iterator_begin(ref_store, refs->gitcommondir);
2192 } else {
2193 return merge_ref_iterator_begin(
2194 0,
2195 reflog_iterator_begin(ref_store, refs->gitdir),
2196 reflog_iterator_begin(ref_store, refs->gitcommondir),
2197 reflog_iterator_select, refs);
2198 }
2199 }
2200
2201 /*
2202 * If update is a direct update of head_ref (the reference pointed to
2203 * by HEAD), then add an extra REF_LOG_ONLY update for HEAD.
2204 */
2205 static int split_head_update(struct ref_update *update,
2206 struct ref_transaction *transaction,
2207 const char *head_ref,
2208 struct string_list *affected_refnames,
2209 struct strbuf *err)
2210 {
2211 struct string_list_item *item;
2212 struct ref_update *new_update;
2213
2214 if ((update->flags & REF_LOG_ONLY) ||
2215 (update->flags & REF_IS_PRUNING) ||
2216 (update->flags & REF_UPDATE_VIA_HEAD))
2217 return 0;
2218
2219 if (strcmp(update->refname, head_ref))
2220 return 0;
2221
2222 /*
2223 * First make sure that HEAD is not already in the
2224 * transaction. This check is O(lg N) in the transaction
2225 * size, but it happens at most once per transaction.
2226 */
2227 if (string_list_has_string(affected_refnames, "HEAD")) {
2228 /* An entry already existed */
2229 strbuf_addf(err,
2230 "multiple updates for 'HEAD' (including one "
2231 "via its referent '%s') are not allowed",
2232 update->refname);
2233 return TRANSACTION_NAME_CONFLICT;
2234 }
2235
2236 new_update = ref_transaction_add_update(
2237 transaction, "HEAD",
2238 update->flags | REF_LOG_ONLY | REF_NO_DEREF,
2239 &update->new_oid, &update->old_oid,
2240 update->msg);
2241
2242 /*
2243 * Add "HEAD". This insertion is O(N) in the transaction
2244 * size, but it happens at most once per transaction.
2245 * Add new_update->refname instead of a literal "HEAD".
2246 */
2247 if (strcmp(new_update->refname, "HEAD"))
2248 BUG("%s unexpectedly not 'HEAD'", new_update->refname);
2249 item = string_list_insert(affected_refnames, new_update->refname);
2250 item->util = new_update;
2251
2252 return 0;
2253 }
2254
2255 /*
2256 * update is for a symref that points at referent and doesn't have
2257 * REF_NO_DEREF set. Split it into two updates:
2258 * - The original update, but with REF_LOG_ONLY and REF_NO_DEREF set
2259 * - A new, separate update for the referent reference
2260 * Note that the new update will itself be subject to splitting when
2261 * the iteration gets to it.
2262 */
2263 static int split_symref_update(struct ref_update *update,
2264 const char *referent,
2265 struct ref_transaction *transaction,
2266 struct string_list *affected_refnames,
2267 struct strbuf *err)
2268 {
2269 struct string_list_item *item;
2270 struct ref_update *new_update;
2271 unsigned int new_flags;
2272
2273 /*
2274 * First make sure that referent is not already in the
2275 * transaction. This check is O(lg N) in the transaction
2276 * size, but it happens at most once per symref in a
2277 * transaction.
2278 */
2279 if (string_list_has_string(affected_refnames, referent)) {
2280 /* An entry already exists */
2281 strbuf_addf(err,
2282 "multiple updates for '%s' (including one "
2283 "via symref '%s') are not allowed",
2284 referent, update->refname);
2285 return TRANSACTION_NAME_CONFLICT;
2286 }
2287
2288 new_flags = update->flags;
2289 if (!strcmp(update->refname, "HEAD")) {
2290 /*
2291 * Record that the new update came via HEAD, so that
2292 * when we process it, split_head_update() doesn't try
2293 * to add another reflog update for HEAD. Note that
2294 * this bit will be propagated if the new_update
2295 * itself needs to be split.
2296 */
2297 new_flags |= REF_UPDATE_VIA_HEAD;
2298 }
2299
2300 new_update = ref_transaction_add_update(
2301 transaction, referent, new_flags,
2302 &update->new_oid, &update->old_oid,
2303 update->msg);
2304
2305 new_update->parent_update = update;
2306
2307 /*
2308 * Change the symbolic ref update to log only. Also, it
2309 * doesn't need to check its old OID value, as that will be
2310 * done when new_update is processed.
2311 */
2312 update->flags |= REF_LOG_ONLY | REF_NO_DEREF;
2313 update->flags &= ~REF_HAVE_OLD;
2314
2315 /*
2316 * Add the referent. This insertion is O(N) in the transaction
2317 * size, but it happens at most once per symref in a
2318 * transaction. Make sure to add new_update->refname, which will
2319 * be valid as long as affected_refnames is in use, and NOT
2320 * referent, which might soon be freed by our caller.
2321 */
2322 item = string_list_insert(affected_refnames, new_update->refname);
2323 if (item->util)
2324 BUG("%s unexpectedly found in affected_refnames",
2325 new_update->refname);
2326 item->util = new_update;
2327
2328 return 0;
2329 }
2330
2331 /*
2332 * Return the refname under which update was originally requested.
2333 */
2334 static const char *original_update_refname(struct ref_update *update)
2335 {
2336 while (update->parent_update)
2337 update = update->parent_update;
2338
2339 return update->refname;
2340 }
2341
2342 /*
2343 * Check whether the REF_HAVE_OLD and old_oid values stored in update
2344 * are consistent with oid, which is the reference's current value. If
2345 * everything is OK, return 0; otherwise, write an error message to
2346 * err and return -1.
2347 */
2348 static int check_old_oid(struct ref_update *update, struct object_id *oid,
2349 struct strbuf *err)
2350 {
2351 if (!(update->flags & REF_HAVE_OLD) ||
2352 oideq(oid, &update->old_oid))
2353 return 0;
2354
2355 if (is_null_oid(&update->old_oid))
2356 strbuf_addf(err, "cannot lock ref '%s': "
2357 "reference already exists",
2358 original_update_refname(update));
2359 else if (is_null_oid(oid))
2360 strbuf_addf(err, "cannot lock ref '%s': "
2361 "reference is missing but expected %s",
2362 original_update_refname(update),
2363 oid_to_hex(&update->old_oid));
2364 else
2365 strbuf_addf(err, "cannot lock ref '%s': "
2366 "is at %s but expected %s",
2367 original_update_refname(update),
2368 oid_to_hex(oid),
2369 oid_to_hex(&update->old_oid));
2370
2371 return -1;
2372 }
2373
2374 /*
2375 * Prepare for carrying out update:
2376 * - Lock the reference referred to by update.
2377 * - Read the reference under lock.
2378 * - Check that its old OID value (if specified) is correct, and in
2379 * any case record it in update->lock->old_oid for later use when
2380 * writing the reflog.
2381 * - If it is a symref update without REF_NO_DEREF, split it up into a
2382 * REF_LOG_ONLY update of the symref and add a separate update for
2383 * the referent to transaction.
2384 * - If it is an update of head_ref, add a corresponding REF_LOG_ONLY
2385 * update of HEAD.
2386 */
2387 static int lock_ref_for_update(struct files_ref_store *refs,
2388 struct ref_update *update,
2389 struct ref_transaction *transaction,
2390 const char *head_ref,
2391 struct string_list *affected_refnames,
2392 struct strbuf *err)
2393 {
2394 struct strbuf referent = STRBUF_INIT;
2395 int mustexist = (update->flags & REF_HAVE_OLD) &&
2396 !is_null_oid(&update->old_oid);
2397 int ret = 0;
2398 struct ref_lock *lock;
2399
2400 files_assert_main_repository(refs, "lock_ref_for_update");
2401
2402 if ((update->flags & REF_HAVE_NEW) && is_null_oid(&update->new_oid))
2403 update->flags |= REF_DELETING;
2404
2405 if (head_ref) {
2406 ret = split_head_update(update, transaction, head_ref,
2407 affected_refnames, err);
2408 if (ret)
2409 goto out;
2410 }
2411
2412 ret = lock_raw_ref(refs, update->refname, mustexist,
2413 affected_refnames, NULL,
2414 &lock, &referent,
2415 &update->type, err);
2416 if (ret) {
2417 char *reason;
2418
2419 reason = strbuf_detach(err, NULL);
2420 strbuf_addf(err, "cannot lock ref '%s': %s",
2421 original_update_refname(update), reason);
2422 free(reason);
2423 goto out;
2424 }
2425
2426 update->backend_data = lock;
2427
2428 if (update->type & REF_ISSYMREF) {
2429 if (update->flags & REF_NO_DEREF) {
2430 /*
2431 * We won't be reading the referent as part of
2432 * the transaction, so we have to read it here
2433 * to record and possibly check old_oid:
2434 */
2435 if (refs_read_ref_full(&refs->base,
2436 referent.buf, 0,
2437 &lock->old_oid, NULL)) {
2438 if (update->flags & REF_HAVE_OLD) {
2439 strbuf_addf(err, "cannot lock ref '%s': "
2440 "error reading reference",
2441 original_update_refname(update));
2442 ret = TRANSACTION_GENERIC_ERROR;
2443 goto out;
2444 }
2445 } else if (check_old_oid(update, &lock->old_oid, err)) {
2446 ret = TRANSACTION_GENERIC_ERROR;
2447 goto out;
2448 }
2449 } else {
2450 /*
2451 * Create a new update for the reference this
2452 * symref is pointing at. Also, we will record
2453 * and verify old_oid for this update as part
2454 * of processing the split-off update, so we
2455 * don't have to do it here.
2456 */
2457 ret = split_symref_update(update,
2458 referent.buf, transaction,
2459 affected_refnames, err);
2460 if (ret)
2461 goto out;
2462 }
2463 } else {
2464 struct ref_update *parent_update;
2465
2466 if (check_old_oid(update, &lock->old_oid, err)) {
2467 ret = TRANSACTION_GENERIC_ERROR;
2468 goto out;
2469 }
2470
2471 /*
2472 * If this update is happening indirectly because of a
2473 * symref update, record the old OID in the parent
2474 * update:
2475 */
2476 for (parent_update = update->parent_update;
2477 parent_update;
2478 parent_update = parent_update->parent_update) {
2479 struct ref_lock *parent_lock = parent_update->backend_data;
2480 oidcpy(&parent_lock->old_oid, &lock->old_oid);
2481 }
2482 }
2483
2484 if ((update->flags & REF_HAVE_NEW) &&
2485 !(update->flags & REF_DELETING) &&
2486 !(update->flags & REF_LOG_ONLY)) {
2487 if (!(update->type & REF_ISSYMREF) &&
2488 oideq(&lock->old_oid, &update->new_oid)) {
2489 /*
2490 * The reference already has the desired
2491 * value, so we don't need to write it.
2492 */
2493 } else if (write_ref_to_lockfile(lock, &update->new_oid,
2494 err)) {
2495 char *write_err = strbuf_detach(err, NULL);
2496
2497 /*
2498 * The lock was freed upon failure of
2499 * write_ref_to_lockfile():
2500 */
2501 update->backend_data = NULL;
2502 strbuf_addf(err,
2503 "cannot update ref '%s': %s",
2504 update->refname, write_err);
2505 free(write_err);
2506 ret = TRANSACTION_GENERIC_ERROR;
2507 goto out;
2508 } else {
2509 update->flags |= REF_NEEDS_COMMIT;
2510 }
2511 }
2512 if (!(update->flags & REF_NEEDS_COMMIT)) {
2513 /*
2514 * We didn't call write_ref_to_lockfile(), so
2515 * the lockfile is still open. Close it to
2516 * free up the file descriptor:
2517 */
2518 if (close_ref_gently(lock)) {
2519 strbuf_addf(err, "couldn't close '%s.lock'",
2520 update->refname);
2521 ret = TRANSACTION_GENERIC_ERROR;
2522 goto out;
2523 }
2524 }
2525
2526 out:
2527 strbuf_release(&referent);
2528 return ret;
2529 }
2530
2531 struct files_transaction_backend_data {
2532 struct ref_transaction *packed_transaction;
2533 int packed_refs_locked;
2534 };
2535
2536 /*
2537 * Unlock any references in `transaction` that are still locked, and
2538 * mark the transaction closed.
2539 */
2540 static void files_transaction_cleanup(struct files_ref_store *refs,
2541 struct ref_transaction *transaction)
2542 {
2543 size_t i;
2544 struct files_transaction_backend_data *backend_data =
2545 transaction->backend_data;
2546 struct strbuf err = STRBUF_INIT;
2547
2548 for (i = 0; i < transaction->nr; i++) {
2549 struct ref_update *update = transaction->updates[i];
2550 struct ref_lock *lock = update->backend_data;
2551
2552 if (lock) {
2553 unlock_ref(lock);
2554 update->backend_data = NULL;
2555 }
2556 }
2557
2558 if (backend_data->packed_transaction &&
2559 ref_transaction_abort(backend_data->packed_transaction, &err)) {
2560 error("error aborting transaction: %s", err.buf);
2561 strbuf_release(&err);
2562 }
2563
2564 if (backend_data->packed_refs_locked)
2565 packed_refs_unlock(refs->packed_ref_store);
2566
2567 free(backend_data);
2568
2569 transaction->state = REF_TRANSACTION_CLOSED;
2570 }
2571
2572 static int files_transaction_prepare(struct ref_store *ref_store,
2573 struct ref_transaction *transaction,
2574 struct strbuf *err)
2575 {
2576 struct files_ref_store *refs =
2577 files_downcast(ref_store, REF_STORE_WRITE,
2578 "ref_transaction_prepare");
2579 size_t i;
2580 int ret = 0;
2581 struct string_list affected_refnames = STRING_LIST_INIT_NODUP;
2582 char *head_ref = NULL;
2583 int head_type;
2584 struct files_transaction_backend_data *backend_data;
2585 struct ref_transaction *packed_transaction = NULL;
2586
2587 assert(err);
2588
2589 if (!transaction->nr)
2590 goto cleanup;
2591
2592 backend_data = xcalloc(1, sizeof(*backend_data));
2593 transaction->backend_data = backend_data;
2594
2595 /*
2596 * Fail if a refname appears more than once in the
2597 * transaction. (If we end up splitting up any updates using
2598 * split_symref_update() or split_head_update(), those
2599 * functions will check that the new updates don't have the
2600 * same refname as any existing ones.) Also fail if any of the
2601 * updates use REF_IS_PRUNING without REF_NO_DEREF.
2602 */
2603 for (i = 0; i < transaction->nr; i++) {
2604 struct ref_update *update = transaction->updates[i];
2605 struct string_list_item *item =
2606 string_list_append(&affected_refnames, update->refname);
2607
2608 if ((update->flags & REF_IS_PRUNING) &&
2609 !(update->flags & REF_NO_DEREF))
2610 BUG("REF_IS_PRUNING set without REF_NO_DEREF");
2611
2612 /*
2613 * We store a pointer to update in item->util, but at
2614 * the moment we never use the value of this field
2615 * except to check whether it is non-NULL.
2616 */
2617 item->util = update;
2618 }
2619 string_list_sort(&affected_refnames);
2620 if (ref_update_reject_duplicates(&affected_refnames, err)) {
2621 ret = TRANSACTION_GENERIC_ERROR;
2622 goto cleanup;
2623 }
2624
2625 /*
2626 * Special hack: If a branch is updated directly and HEAD
2627 * points to it (may happen on the remote side of a push
2628 * for example) then logically the HEAD reflog should be
2629 * updated too.
2630 *
2631 * A generic solution would require reverse symref lookups,
2632 * but finding all symrefs pointing to a given branch would be
2633 * rather costly for this rare event (the direct update of a
2634 * branch) to be worth it. So let's cheat and check with HEAD
2635 * only, which should cover 99% of all usage scenarios (even
2636 * 100% of the default ones).
2637 *
2638 * So if HEAD is a symbolic reference, then record the name of
2639 * the reference that it points to. If we see an update of
2640 * head_ref within the transaction, then split_head_update()
2641 * arranges for the reflog of HEAD to be updated, too.
2642 */
2643 head_ref = refs_resolve_refdup(ref_store, "HEAD",
2644 RESOLVE_REF_NO_RECURSE,
2645 NULL, &head_type);
2646
2647 if (head_ref && !(head_type & REF_ISSYMREF)) {
2648 FREE_AND_NULL(head_ref);
2649 }
2650
2651 /*
2652 * Acquire all locks, verify old values if provided, check
2653 * that new values are valid, and write new values to the
2654 * lockfiles, ready to be activated. Only keep one lockfile
2655 * open at a time to avoid running out of file descriptors.
2656 * Note that lock_ref_for_update() might append more updates
2657 * to the transaction.
2658 */
2659 for (i = 0; i < transaction->nr; i++) {
2660 struct ref_update *update = transaction->updates[i];
2661
2662 ret = lock_ref_for_update(refs, update, transaction,
2663 head_ref, &affected_refnames, err);
2664 if (ret)
2665 goto cleanup;
2666
2667 if (update->flags & REF_DELETING &&
2668 !(update->flags & REF_LOG_ONLY) &&
2669 !(update->flags & REF_IS_PRUNING)) {
2670 /*
2671 * This reference has to be deleted from
2672 * packed-refs if it exists there.
2673 */
2674 if (!packed_transaction) {
2675 packed_transaction = ref_store_transaction_begin(
2676 refs->packed_ref_store, err);
2677 if (!packed_transaction) {
2678 ret = TRANSACTION_GENERIC_ERROR;
2679 goto cleanup;
2680 }
2681
2682 backend_data->packed_transaction =
2683 packed_transaction;
2684 }
2685
2686 ref_transaction_add_update(
2687 packed_transaction, update->refname,
2688 REF_HAVE_NEW | REF_NO_DEREF,
2689 &update->new_oid, NULL,
2690 NULL);
2691 }
2692 }
2693
2694 if (packed_transaction) {
2695 if (packed_refs_lock(refs->packed_ref_store, 0, err)) {
2696 ret = TRANSACTION_GENERIC_ERROR;
2697 goto cleanup;
2698 }
2699 backend_data->packed_refs_locked = 1;
2700
2701 if (is_packed_transaction_needed(refs->packed_ref_store,
2702 packed_transaction)) {
2703 ret = ref_transaction_prepare(packed_transaction, err);
2704 /*
2705 * A failure during the prepare step will abort
2706 * itself, but not free. Do that now, and disconnect
2707 * from the files_transaction so it does not try to
2708 * abort us when we hit the cleanup code below.
2709 */
2710 if (ret) {
2711 ref_transaction_free(packed_transaction);
2712 backend_data->packed_transaction = NULL;
2713 }
2714 } else {
2715 /*
2716 * We can skip rewriting the `packed-refs`
2717 * file. But we do need to leave it locked, so
2718 * that somebody else doesn't pack a reference
2719 * that we are trying to delete.
2720 *
2721 * We need to disconnect our transaction from
2722 * backend_data, since the abort (whether successful or
2723 * not) will free it.
2724 */
2725 backend_data->packed_transaction = NULL;
2726 if (ref_transaction_abort(packed_transaction, err)) {
2727 ret = TRANSACTION_GENERIC_ERROR;
2728 goto cleanup;
2729 }
2730 }
2731 }
2732
2733 cleanup:
2734 free(head_ref);
2735 string_list_clear(&affected_refnames, 0);
2736
2737 if (ret)
2738 files_transaction_cleanup(refs, transaction);
2739 else
2740 transaction->state = REF_TRANSACTION_PREPARED;
2741
2742 return ret;
2743 }
2744
2745 static int files_transaction_finish(struct ref_store *ref_store,
2746 struct ref_transaction *transaction,
2747 struct strbuf *err)
2748 {
2749 struct files_ref_store *refs =
2750 files_downcast(ref_store, 0, "ref_transaction_finish");
2751 size_t i;
2752 int ret = 0;
2753 struct strbuf sb = STRBUF_INIT;
2754 struct files_transaction_backend_data *backend_data;
2755 struct ref_transaction *packed_transaction;
2756
2757
2758 assert(err);
2759
2760 if (!transaction->nr) {
2761 transaction->state = REF_TRANSACTION_CLOSED;
2762 return 0;
2763 }
2764
2765 backend_data = transaction->backend_data;
2766 packed_transaction = backend_data->packed_transaction;
2767
2768 /* Perform updates first so live commits remain referenced */
2769 for (i = 0; i < transaction->nr; i++) {
2770 struct ref_update *update = transaction->updates[i];
2771 struct ref_lock *lock = update->backend_data;
2772
2773 if (update->flags & REF_NEEDS_COMMIT ||
2774 update->flags & REF_LOG_ONLY) {
2775 if (files_log_ref_write(refs,
2776 lock->ref_name,
2777 &lock->old_oid,
2778 &update->new_oid,
2779 update->msg, update->flags,
2780 err)) {
2781 char *old_msg = strbuf_detach(err, NULL);
2782
2783 strbuf_addf(err, "cannot update the ref '%s': %s",
2784 lock->ref_name, old_msg);
2785 free(old_msg);
2786 unlock_ref(lock);
2787 update->backend_data = NULL;
2788 ret = TRANSACTION_GENERIC_ERROR;
2789 goto cleanup;
2790 }
2791 }
2792 if (update->flags & REF_NEEDS_COMMIT) {
2793 clear_loose_ref_cache(refs);
2794 if (commit_ref(lock)) {
2795 strbuf_addf(err, "couldn't set '%s'", lock->ref_name);
2796 unlock_ref(lock);
2797 update->backend_data = NULL;
2798 ret = TRANSACTION_GENERIC_ERROR;
2799 goto cleanup;
2800 }
2801 }
2802 }
2803
2804 /*
2805 * Now that updates are safely completed, we can perform
2806 * deletes. First delete the reflogs of any references that
2807 * will be deleted, since (in the unexpected event of an
2808 * error) leaving a reference without a reflog is less bad
2809 * than leaving a reflog without a reference (the latter is a
2810 * mildly invalid repository state):
2811 */
2812 for (i = 0; i < transaction->nr; i++) {
2813 struct ref_update *update = transaction->updates[i];
2814 if (update->flags & REF_DELETING &&
2815 !(update->flags & REF_LOG_ONLY) &&
2816 !(update->flags & REF_IS_PRUNING)) {
2817 strbuf_reset(&sb);
2818 files_reflog_path(refs, &sb, update->refname);
2819 if (!unlink_or_warn(sb.buf))
2820 try_remove_empty_parents(refs, update->refname,
2821 REMOVE_EMPTY_PARENTS_REFLOG);
2822 }
2823 }
2824
2825 /*
2826 * Perform deletes now that updates are safely completed.
2827 *
2828 * First delete any packed versions of the references, while
2829 * retaining the packed-refs lock:
2830 */
2831 if (packed_transaction) {
2832 ret = ref_transaction_commit(packed_transaction, err);
2833 ref_transaction_free(packed_transaction);
2834 packed_transaction = NULL;
2835 backend_data->packed_transaction = NULL;
2836 if (ret)
2837 goto cleanup;
2838 }
2839
2840 /* Now delete the loose versions of the references: */
2841 for (i = 0; i < transaction->nr; i++) {
2842 struct ref_update *update = transaction->updates[i];
2843 struct ref_lock *lock = update->backend_data;
2844
2845 if (update->flags & REF_DELETING &&
2846 !(update->flags & REF_LOG_ONLY)) {
2847 if (!(update->type & REF_ISPACKED) ||
2848 update->type & REF_ISSYMREF) {
2849 /* It is a loose reference. */
2850 strbuf_reset(&sb);
2851 files_ref_path(refs, &sb, lock->ref_name);
2852 if (unlink_or_msg(sb.buf, err)) {
2853 ret = TRANSACTION_GENERIC_ERROR;
2854 goto cleanup;
2855 }
2856 update->flags |= REF_DELETED_LOOSE;
2857 }
2858 }
2859 }
2860
2861 clear_loose_ref_cache(refs);
2862
2863 cleanup:
2864 files_transaction_cleanup(refs, transaction);
2865
2866 for (i = 0; i < transaction->nr; i++) {
2867 struct ref_update *update = transaction->updates[i];
2868
2869 if (update->flags & REF_DELETED_LOOSE) {
2870 /*
2871 * The loose reference was deleted. Delete any
2872 * empty parent directories. (Note that this
2873 * can only work because we have already
2874 * removed the lockfile.)
2875 */
2876 try_remove_empty_parents(refs, update->refname,
2877 REMOVE_EMPTY_PARENTS_REF);
2878 }
2879 }
2880
2881 strbuf_release(&sb);
2882 return ret;
2883 }
2884
2885 static int files_transaction_abort(struct ref_store *ref_store,
2886 struct ref_transaction *transaction,
2887 struct strbuf *err)
2888 {
2889 struct files_ref_store *refs =
2890 files_downcast(ref_store, 0, "ref_transaction_abort");
2891
2892 files_transaction_cleanup(refs, transaction);
2893 return 0;
2894 }
2895
2896 static int ref_present(const char *refname,
2897 const struct object_id *oid, int flags, void *cb_data)
2898 {
2899 struct string_list *affected_refnames = cb_data;
2900
2901 return string_list_has_string(affected_refnames, refname);
2902 }
2903
2904 static int files_initial_transaction_commit(struct ref_store *ref_store,
2905 struct ref_transaction *transaction,
2906 struct strbuf *err)
2907 {
2908 struct files_ref_store *refs =
2909 files_downcast(ref_store, REF_STORE_WRITE,
2910 "initial_ref_transaction_commit");
2911 size_t i;
2912 int ret = 0;
2913 struct string_list affected_refnames = STRING_LIST_INIT_NODUP;
2914 struct ref_transaction *packed_transaction = NULL;
2915
2916 assert(err);
2917
2918 if (transaction->state != REF_TRANSACTION_OPEN)
2919 BUG("commit called for transaction that is not open");
2920
2921 /* Fail if a refname appears more than once in the transaction: */
2922 for (i = 0; i < transaction->nr; i++)
2923 string_list_append(&affected_refnames,
2924 transaction->updates[i]->refname);
2925 string_list_sort(&affected_refnames);
2926 if (ref_update_reject_duplicates(&affected_refnames, err)) {
2927 ret = TRANSACTION_GENERIC_ERROR;
2928 goto cleanup;
2929 }
2930
2931 /*
2932 * It's really undefined to call this function in an active
2933 * repository or when there are existing references: we are
2934 * only locking and changing packed-refs, so (1) any
2935 * simultaneous processes might try to change a reference at
2936 * the same time we do, and (2) any existing loose versions of
2937 * the references that we are setting would have precedence
2938 * over our values. But some remote helpers create the remote
2939 * "HEAD" and "master" branches before calling this function,
2940 * so here we really only check that none of the references
2941 * that we are creating already exists.
2942 */
2943 if (refs_for_each_rawref(&refs->base, ref_present,
2944 &affected_refnames))
2945 BUG("initial ref transaction called with existing refs");
2946
2947 packed_transaction = ref_store_transaction_begin(refs->packed_ref_store, err);
2948 if (!packed_transaction) {
2949 ret = TRANSACTION_GENERIC_ERROR;
2950 goto cleanup;
2951 }
2952
2953 for (i = 0; i < transaction->nr; i++) {
2954 struct ref_update *update = transaction->updates[i];
2955
2956 if ((update->flags & REF_HAVE_OLD) &&
2957 !is_null_oid(&update->old_oid))
2958 BUG("initial ref transaction with old_sha1 set");
2959 if (refs_verify_refname_available(&refs->base, update->refname,
2960 &affected_refnames, NULL,
2961 err)) {
2962 ret = TRANSACTION_NAME_CONFLICT;
2963 goto cleanup;
2964 }
2965
2966 /*
2967 * Add a reference creation for this reference to the
2968 * packed-refs transaction:
2969 */
2970 ref_transaction_add_update(packed_transaction, update->refname,
2971 update->flags & ~REF_HAVE_OLD,
2972 &update->new_oid, &update->old_oid,
2973 NULL);
2974 }
2975
2976 if (packed_refs_lock(refs->packed_ref_store, 0, err)) {
2977 ret = TRANSACTION_GENERIC_ERROR;
2978 goto cleanup;
2979 }
2980
2981 if (initial_ref_transaction_commit(packed_transaction, err)) {
2982 ret = TRANSACTION_GENERIC_ERROR;
2983 }
2984
2985 packed_refs_unlock(refs->packed_ref_store);
2986 cleanup:
2987 if (packed_transaction)
2988 ref_transaction_free(packed_transaction);
2989 transaction->state = REF_TRANSACTION_CLOSED;
2990 string_list_clear(&affected_refnames, 0);
2991 return ret;
2992 }
2993
2994 struct expire_reflog_cb {
2995 unsigned int flags;
2996 reflog_expiry_should_prune_fn *should_prune_fn;
2997 void *policy_cb;
2998 FILE *newlog;
2999 struct object_id last_kept_oid;
3000 };
3001
3002 static int expire_reflog_ent(struct object_id *ooid, struct object_id *noid,
3003 const char *email, timestamp_t timestamp, int tz,
3004 const char *message, void *cb_data)
3005 {
3006 struct expire_reflog_cb *cb = cb_data;
3007 struct expire_reflog_policy_cb *policy_cb = cb->policy_cb;
3008
3009 if (cb->flags & EXPIRE_REFLOGS_REWRITE)
3010 ooid = &cb->last_kept_oid;
3011
3012 if ((*cb->should_prune_fn)(ooid, noid, email, timestamp, tz,
3013 message, policy_cb)) {
3014 if (!cb->newlog)
3015 printf("would prune %s", message);
3016 else if (cb->flags & EXPIRE_REFLOGS_VERBOSE)
3017 printf("prune %s", message);
3018 } else {
3019 if (cb->newlog) {
3020 fprintf(cb->newlog, "%s %s %s %"PRItime" %+05d\t%s",
3021 oid_to_hex(ooid), oid_to_hex(noid),
3022 email, timestamp, tz, message);
3023 oidcpy(&cb->last_kept_oid, noid);
3024 }
3025 if (cb->flags & EXPIRE_REFLOGS_VERBOSE)
3026 printf("keep %s", message);
3027 }
3028 return 0;
3029 }
3030
3031 static int files_reflog_expire(struct ref_store *ref_store,
3032 const char *refname, const struct object_id *oid,
3033 unsigned int flags,
3034 reflog_expiry_prepare_fn prepare_fn,
3035 reflog_expiry_should_prune_fn should_prune_fn,
3036 reflog_expiry_cleanup_fn cleanup_fn,
3037 void *policy_cb_data)
3038 {
3039 struct files_ref_store *refs =
3040 files_downcast(ref_store, REF_STORE_WRITE, "reflog_expire");
3041 struct lock_file reflog_lock = LOCK_INIT;
3042 struct expire_reflog_cb cb;
3043 struct ref_lock *lock;
3044 struct strbuf log_file_sb = STRBUF_INIT;
3045 char *log_file;
3046 int status = 0;
3047 int type;
3048 struct strbuf err = STRBUF_INIT;
3049
3050 memset(&cb, 0, sizeof(cb));
3051 cb.flags = flags;
3052 cb.policy_cb = policy_cb_data;
3053 cb.should_prune_fn = should_prune_fn;
3054
3055 /*
3056 * The reflog file is locked by holding the lock on the
3057 * reference itself, plus we might need to update the
3058 * reference if --updateref was specified:
3059 */
3060 lock = lock_ref_oid_basic(refs, refname, oid,
3061 NULL, NULL, REF_NO_DEREF,
3062 &type, &err);
3063 if (!lock) {
3064 error("cannot lock ref '%s': %s", refname, err.buf);
3065 strbuf_release(&err);
3066 return -1;
3067 }
3068 if (!refs_reflog_exists(ref_store, refname)) {
3069 unlock_ref(lock);
3070 return 0;
3071 }
3072
3073 files_reflog_path(refs, &log_file_sb, refname);
3074 log_file = strbuf_detach(&log_file_sb, NULL);
3075 if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {
3076 /*
3077 * Even though holding $GIT_DIR/logs/$reflog.lock has
3078 * no locking implications, we use the lock_file
3079 * machinery here anyway because it does a lot of the
3080 * work we need, including cleaning up if the program
3081 * exits unexpectedly.
3082 */
3083 if (hold_lock_file_for_update(&reflog_lock, log_file, 0) < 0) {
3084 struct strbuf err = STRBUF_INIT;
3085 unable_to_lock_message(log_file, errno, &err);
3086 error("%s", err.buf);
3087 strbuf_release(&err);
3088 goto failure;
3089 }
3090 cb.newlog = fdopen_lock_file(&reflog_lock, "w");
3091 if (!cb.newlog) {
3092 error("cannot fdopen %s (%s)",
3093 get_lock_file_path(&reflog_lock), strerror(errno));
3094 goto failure;
3095 }
3096 }
3097
3098 (*prepare_fn)(refname, oid, cb.policy_cb);
3099 refs_for_each_reflog_ent(ref_store, refname, expire_reflog_ent, &cb);
3100 (*cleanup_fn)(cb.policy_cb);
3101
3102 if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {
3103 /*
3104 * It doesn't make sense to adjust a reference pointed
3105 * to by a symbolic ref based on expiring entries in
3106 * the symbolic reference's reflog. Nor can we update
3107 * a reference if there are no remaining reflog
3108 * entries.
3109 */
3110 int update = (flags & EXPIRE_REFLOGS_UPDATE_REF) &&
3111 !(type & REF_ISSYMREF) &&
3112 !is_null_oid(&cb.last_kept_oid);
3113
3114 if (close_lock_file_gently(&reflog_lock)) {
3115 status |= error("couldn't write %s: %s", log_file,
3116 strerror(errno));
3117 rollback_lock_file(&reflog_lock);
3118 } else if (update &&
3119 (write_in_full(get_lock_file_fd(&lock->lk),
3120 oid_to_hex(&cb.last_kept_oid), the_hash_algo->hexsz) < 0 ||
3121 write_str_in_full(get_lock_file_fd(&lock->lk), "\n") < 0 ||
3122 close_ref_gently(lock) < 0)) {
3123 status |= error("couldn't write %s",
3124 get_lock_file_path(&lock->lk));
3125 rollback_lock_file(&reflog_lock);
3126 } else if (commit_lock_file(&reflog_lock)) {
3127 status |= error("unable to write reflog '%s' (%s)",
3128 log_file, strerror(errno));
3129 } else if (update && commit_ref(lock)) {
3130 status |= error("couldn't set %s", lock->ref_name);
3131 }
3132 }
3133 free(log_file);
3134 unlock_ref(lock);
3135 return status;
3136
3137 failure:
3138 rollback_lock_file(&reflog_lock);
3139 free(log_file);
3140 unlock_ref(lock);
3141 return -1;
3142 }
3143
3144 static int files_init_db(struct ref_store *ref_store, struct strbuf *err)
3145 {
3146 struct files_ref_store *refs =
3147 files_downcast(ref_store, REF_STORE_WRITE, "init_db");
3148 struct strbuf sb = STRBUF_INIT;
3149
3150 /*
3151 * Create .git/refs/{heads,tags}
3152 */
3153 files_ref_path(refs, &sb, "refs/heads");
3154 safe_create_dir(sb.buf, 1);
3155
3156 strbuf_reset(&sb);
3157 files_ref_path(refs, &sb, "refs/tags");
3158 safe_create_dir(sb.buf, 1);
3159
3160 strbuf_release(&sb);
3161 return 0;
3162 }
3163
3164 struct ref_storage_be refs_be_files = {
3165 NULL,
3166 "files",
3167 files_ref_store_create,
3168 files_init_db,
3169 files_transaction_prepare,
3170 files_transaction_finish,
3171 files_transaction_abort,
3172 files_initial_transaction_commit,
3173
3174 files_pack_refs,
3175 files_create_symref,
3176 files_delete_refs,
3177 files_rename_ref,
3178 files_copy_ref,
3179
3180 files_ref_iterator_begin,
3181 files_read_raw_ref,
3182
3183 files_reflog_iterator_begin,
3184 files_for_each_reflog_ent,
3185 files_for_each_reflog_ent_reverse,
3186 files_reflog_exists,
3187 files_create_reflog,
3188 files_delete_reflog,
3189 files_reflog_expire
3190 };