]> git.ipfire.org Git - thirdparty/git.git/blob - refs/files-backend.c
credential: update description for credential_from_url_gently
[thirdparty/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 (skip_prefix(buf, "ref:", &buf)) {
469 while (isspace(*buf))
470 buf++;
471
472 strbuf_reset(referent);
473 strbuf_addstr(referent, buf);
474 *type |= REF_ISSYMREF;
475 ret = 0;
476 goto out;
477 }
478
479 /*
480 * Please note that FETCH_HEAD has additional
481 * data after the sha.
482 */
483 if (parse_oid_hex(buf, oid, &p) ||
484 (*p != '\0' && !isspace(*p))) {
485 *type |= REF_ISBROKEN;
486 errno = EINVAL;
487 goto out;
488 }
489
490 ret = 0;
491
492 out:
493 save_errno = errno;
494 strbuf_release(&sb_path);
495 strbuf_release(&sb_contents);
496 errno = save_errno;
497 return ret;
498 }
499
500 static void unlock_ref(struct ref_lock *lock)
501 {
502 rollback_lock_file(&lock->lk);
503 free(lock->ref_name);
504 free(lock);
505 }
506
507 /*
508 * Lock refname, without following symrefs, and set *lock_p to point
509 * at a newly-allocated lock object. Fill in lock->old_oid, referent,
510 * and type similarly to read_raw_ref().
511 *
512 * The caller must verify that refname is a "safe" reference name (in
513 * the sense of refname_is_safe()) before calling this function.
514 *
515 * If the reference doesn't already exist, verify that refname doesn't
516 * have a D/F conflict with any existing references. extras and skip
517 * are passed to refs_verify_refname_available() for this check.
518 *
519 * If mustexist is not set and the reference is not found or is
520 * broken, lock the reference anyway but clear old_oid.
521 *
522 * Return 0 on success. On failure, write an error message to err and
523 * return TRANSACTION_NAME_CONFLICT or TRANSACTION_GENERIC_ERROR.
524 *
525 * Implementation note: This function is basically
526 *
527 * lock reference
528 * read_raw_ref()
529 *
530 * but it includes a lot more code to
531 * - Deal with possible races with other processes
532 * - Avoid calling refs_verify_refname_available() when it can be
533 * avoided, namely if we were successfully able to read the ref
534 * - Generate informative error messages in the case of failure
535 */
536 static int lock_raw_ref(struct files_ref_store *refs,
537 const char *refname, int mustexist,
538 const struct string_list *extras,
539 const struct string_list *skip,
540 struct ref_lock **lock_p,
541 struct strbuf *referent,
542 unsigned int *type,
543 struct strbuf *err)
544 {
545 struct ref_lock *lock;
546 struct strbuf ref_file = STRBUF_INIT;
547 int attempts_remaining = 3;
548 int ret = TRANSACTION_GENERIC_ERROR;
549
550 assert(err);
551 files_assert_main_repository(refs, "lock_raw_ref");
552
553 *type = 0;
554
555 /* First lock the file so it can't change out from under us. */
556
557 *lock_p = lock = xcalloc(1, sizeof(*lock));
558
559 lock->ref_name = xstrdup(refname);
560 files_ref_path(refs, &ref_file, refname);
561
562 retry:
563 switch (safe_create_leading_directories(ref_file.buf)) {
564 case SCLD_OK:
565 break; /* success */
566 case SCLD_EXISTS:
567 /*
568 * Suppose refname is "refs/foo/bar". We just failed
569 * to create the containing directory, "refs/foo",
570 * because there was a non-directory in the way. This
571 * indicates a D/F conflict, probably because of
572 * another reference such as "refs/foo". There is no
573 * reason to expect this error to be transitory.
574 */
575 if (refs_verify_refname_available(&refs->base, refname,
576 extras, skip, err)) {
577 if (mustexist) {
578 /*
579 * To the user the relevant error is
580 * that the "mustexist" reference is
581 * missing:
582 */
583 strbuf_reset(err);
584 strbuf_addf(err, "unable to resolve reference '%s'",
585 refname);
586 } else {
587 /*
588 * The error message set by
589 * refs_verify_refname_available() is
590 * OK.
591 */
592 ret = TRANSACTION_NAME_CONFLICT;
593 }
594 } else {
595 /*
596 * The file that is in the way isn't a loose
597 * reference. Report it as a low-level
598 * failure.
599 */
600 strbuf_addf(err, "unable to create lock file %s.lock; "
601 "non-directory in the way",
602 ref_file.buf);
603 }
604 goto error_return;
605 case SCLD_VANISHED:
606 /* Maybe another process was tidying up. Try again. */
607 if (--attempts_remaining > 0)
608 goto retry;
609 /* fall through */
610 default:
611 strbuf_addf(err, "unable to create directory for %s",
612 ref_file.buf);
613 goto error_return;
614 }
615
616 if (hold_lock_file_for_update_timeout(
617 &lock->lk, ref_file.buf, LOCK_NO_DEREF,
618 get_files_ref_lock_timeout_ms()) < 0) {
619 if (errno == ENOENT && --attempts_remaining > 0) {
620 /*
621 * Maybe somebody just deleted one of the
622 * directories leading to ref_file. Try
623 * again:
624 */
625 goto retry;
626 } else {
627 unable_to_lock_message(ref_file.buf, errno, err);
628 goto error_return;
629 }
630 }
631
632 /*
633 * Now we hold the lock and can read the reference without
634 * fear that its value will change.
635 */
636
637 if (files_read_raw_ref(&refs->base, refname,
638 &lock->old_oid, referent, type)) {
639 if (errno == ENOENT) {
640 if (mustexist) {
641 /* Garden variety missing reference. */
642 strbuf_addf(err, "unable to resolve reference '%s'",
643 refname);
644 goto error_return;
645 } else {
646 /*
647 * Reference is missing, but that's OK. We
648 * know that there is not a conflict with
649 * another loose reference because
650 * (supposing that we are trying to lock
651 * reference "refs/foo/bar"):
652 *
653 * - We were successfully able to create
654 * the lockfile refs/foo/bar.lock, so we
655 * know there cannot be a loose reference
656 * named "refs/foo".
657 *
658 * - We got ENOENT and not EISDIR, so we
659 * know that there cannot be a loose
660 * reference named "refs/foo/bar/baz".
661 */
662 }
663 } else if (errno == EISDIR) {
664 /*
665 * There is a directory in the way. It might have
666 * contained references that have been deleted. If
667 * we don't require that the reference already
668 * exists, try to remove the directory so that it
669 * doesn't cause trouble when we want to rename the
670 * lockfile into place later.
671 */
672 if (mustexist) {
673 /* Garden variety missing reference. */
674 strbuf_addf(err, "unable to resolve reference '%s'",
675 refname);
676 goto error_return;
677 } else if (remove_dir_recursively(&ref_file,
678 REMOVE_DIR_EMPTY_ONLY)) {
679 if (refs_verify_refname_available(
680 &refs->base, refname,
681 extras, skip, err)) {
682 /*
683 * The error message set by
684 * verify_refname_available() is OK.
685 */
686 ret = TRANSACTION_NAME_CONFLICT;
687 goto error_return;
688 } else {
689 /*
690 * We can't delete the directory,
691 * but we also don't know of any
692 * references that it should
693 * contain.
694 */
695 strbuf_addf(err, "there is a non-empty directory '%s' "
696 "blocking reference '%s'",
697 ref_file.buf, refname);
698 goto error_return;
699 }
700 }
701 } else if (errno == EINVAL && (*type & REF_ISBROKEN)) {
702 strbuf_addf(err, "unable to resolve reference '%s': "
703 "reference broken", refname);
704 goto error_return;
705 } else {
706 strbuf_addf(err, "unable to resolve reference '%s': %s",
707 refname, strerror(errno));
708 goto error_return;
709 }
710
711 /*
712 * If the ref did not exist and we are creating it,
713 * make sure there is no existing packed ref that
714 * conflicts with refname:
715 */
716 if (refs_verify_refname_available(
717 refs->packed_ref_store, refname,
718 extras, skip, err))
719 goto error_return;
720 }
721
722 ret = 0;
723 goto out;
724
725 error_return:
726 unlock_ref(lock);
727 *lock_p = NULL;
728
729 out:
730 strbuf_release(&ref_file);
731 return ret;
732 }
733
734 struct files_ref_iterator {
735 struct ref_iterator base;
736
737 struct ref_iterator *iter0;
738 unsigned int flags;
739 };
740
741 static int files_ref_iterator_advance(struct ref_iterator *ref_iterator)
742 {
743 struct files_ref_iterator *iter =
744 (struct files_ref_iterator *)ref_iterator;
745 int ok;
746
747 while ((ok = ref_iterator_advance(iter->iter0)) == ITER_OK) {
748 if (iter->flags & DO_FOR_EACH_PER_WORKTREE_ONLY &&
749 ref_type(iter->iter0->refname) != REF_TYPE_PER_WORKTREE)
750 continue;
751
752 if (!(iter->flags & DO_FOR_EACH_INCLUDE_BROKEN) &&
753 !ref_resolves_to_object(iter->iter0->refname,
754 iter->iter0->oid,
755 iter->iter0->flags))
756 continue;
757
758 iter->base.refname = iter->iter0->refname;
759 iter->base.oid = iter->iter0->oid;
760 iter->base.flags = iter->iter0->flags;
761 return ITER_OK;
762 }
763
764 iter->iter0 = NULL;
765 if (ref_iterator_abort(ref_iterator) != ITER_DONE)
766 ok = ITER_ERROR;
767
768 return ok;
769 }
770
771 static int files_ref_iterator_peel(struct ref_iterator *ref_iterator,
772 struct object_id *peeled)
773 {
774 struct files_ref_iterator *iter =
775 (struct files_ref_iterator *)ref_iterator;
776
777 return ref_iterator_peel(iter->iter0, peeled);
778 }
779
780 static int files_ref_iterator_abort(struct ref_iterator *ref_iterator)
781 {
782 struct files_ref_iterator *iter =
783 (struct files_ref_iterator *)ref_iterator;
784 int ok = ITER_DONE;
785
786 if (iter->iter0)
787 ok = ref_iterator_abort(iter->iter0);
788
789 base_ref_iterator_free(ref_iterator);
790 return ok;
791 }
792
793 static struct ref_iterator_vtable files_ref_iterator_vtable = {
794 files_ref_iterator_advance,
795 files_ref_iterator_peel,
796 files_ref_iterator_abort
797 };
798
799 static struct ref_iterator *files_ref_iterator_begin(
800 struct ref_store *ref_store,
801 const char *prefix, unsigned int flags)
802 {
803 struct files_ref_store *refs;
804 struct ref_iterator *loose_iter, *packed_iter, *overlay_iter;
805 struct files_ref_iterator *iter;
806 struct ref_iterator *ref_iterator;
807 unsigned int required_flags = REF_STORE_READ;
808
809 if (!(flags & DO_FOR_EACH_INCLUDE_BROKEN))
810 required_flags |= REF_STORE_ODB;
811
812 refs = files_downcast(ref_store, required_flags, "ref_iterator_begin");
813
814 /*
815 * We must make sure that all loose refs are read before
816 * accessing the packed-refs file; this avoids a race
817 * condition if loose refs are migrated to the packed-refs
818 * file by a simultaneous process, but our in-memory view is
819 * from before the migration. We ensure this as follows:
820 * First, we call start the loose refs iteration with its
821 * `prime_ref` argument set to true. This causes the loose
822 * references in the subtree to be pre-read into the cache.
823 * (If they've already been read, that's OK; we only need to
824 * guarantee that they're read before the packed refs, not
825 * *how much* before.) After that, we call
826 * packed_ref_iterator_begin(), which internally checks
827 * whether the packed-ref cache is up to date with what is on
828 * disk, and re-reads it if not.
829 */
830
831 loose_iter = cache_ref_iterator_begin(get_loose_ref_cache(refs),
832 prefix, 1);
833
834 /*
835 * The packed-refs file might contain broken references, for
836 * example an old version of a reference that points at an
837 * object that has since been garbage-collected. This is OK as
838 * long as there is a corresponding loose reference that
839 * overrides it, and we don't want to emit an error message in
840 * this case. So ask the packed_ref_store for all of its
841 * references, and (if needed) do our own check for broken
842 * ones in files_ref_iterator_advance(), after we have merged
843 * the packed and loose references.
844 */
845 packed_iter = refs_ref_iterator_begin(
846 refs->packed_ref_store, prefix, 0,
847 DO_FOR_EACH_INCLUDE_BROKEN);
848
849 overlay_iter = overlay_ref_iterator_begin(loose_iter, packed_iter);
850
851 iter = xcalloc(1, sizeof(*iter));
852 ref_iterator = &iter->base;
853 base_ref_iterator_init(ref_iterator, &files_ref_iterator_vtable,
854 overlay_iter->ordered);
855 iter->iter0 = overlay_iter;
856 iter->flags = flags;
857
858 return ref_iterator;
859 }
860
861 /*
862 * Verify that the reference locked by lock has the value old_oid
863 * (unless it is NULL). Fail if the reference doesn't exist and
864 * mustexist is set. Return 0 on success. On error, write an error
865 * message to err, set errno, and return a negative value.
866 */
867 static int verify_lock(struct ref_store *ref_store, struct ref_lock *lock,
868 const struct object_id *old_oid, int mustexist,
869 struct strbuf *err)
870 {
871 assert(err);
872
873 if (refs_read_ref_full(ref_store, lock->ref_name,
874 mustexist ? RESOLVE_REF_READING : 0,
875 &lock->old_oid, NULL)) {
876 if (old_oid) {
877 int save_errno = errno;
878 strbuf_addf(err, "can't verify ref '%s'", lock->ref_name);
879 errno = save_errno;
880 return -1;
881 } else {
882 oidclr(&lock->old_oid);
883 return 0;
884 }
885 }
886 if (old_oid && !oideq(&lock->old_oid, old_oid)) {
887 strbuf_addf(err, "ref '%s' is at %s but expected %s",
888 lock->ref_name,
889 oid_to_hex(&lock->old_oid),
890 oid_to_hex(old_oid));
891 errno = EBUSY;
892 return -1;
893 }
894 return 0;
895 }
896
897 static int remove_empty_directories(struct strbuf *path)
898 {
899 /*
900 * we want to create a file but there is a directory there;
901 * if that is an empty directory (or a directory that contains
902 * only empty directories), remove them.
903 */
904 return remove_dir_recursively(path, REMOVE_DIR_EMPTY_ONLY);
905 }
906
907 static int create_reflock(const char *path, void *cb)
908 {
909 struct lock_file *lk = cb;
910
911 return hold_lock_file_for_update_timeout(
912 lk, path, LOCK_NO_DEREF,
913 get_files_ref_lock_timeout_ms()) < 0 ? -1 : 0;
914 }
915
916 /*
917 * Locks a ref returning the lock on success and NULL on failure.
918 * On failure errno is set to something meaningful.
919 */
920 static struct ref_lock *lock_ref_oid_basic(struct files_ref_store *refs,
921 const char *refname,
922 const struct object_id *old_oid,
923 const struct string_list *extras,
924 const struct string_list *skip,
925 unsigned int flags, int *type,
926 struct strbuf *err)
927 {
928 struct strbuf ref_file = STRBUF_INIT;
929 struct ref_lock *lock;
930 int last_errno = 0;
931 int mustexist = (old_oid && !is_null_oid(old_oid));
932 int resolve_flags = RESOLVE_REF_NO_RECURSE;
933 int resolved;
934
935 files_assert_main_repository(refs, "lock_ref_oid_basic");
936 assert(err);
937
938 lock = xcalloc(1, sizeof(struct ref_lock));
939
940 if (mustexist)
941 resolve_flags |= RESOLVE_REF_READING;
942 if (flags & REF_DELETING)
943 resolve_flags |= RESOLVE_REF_ALLOW_BAD_NAME;
944
945 files_ref_path(refs, &ref_file, refname);
946 resolved = !!refs_resolve_ref_unsafe(&refs->base,
947 refname, resolve_flags,
948 &lock->old_oid, type);
949 if (!resolved && errno == EISDIR) {
950 /*
951 * we are trying to lock foo but we used to
952 * have foo/bar which now does not exist;
953 * it is normal for the empty directory 'foo'
954 * to remain.
955 */
956 if (remove_empty_directories(&ref_file)) {
957 last_errno = errno;
958 if (!refs_verify_refname_available(
959 &refs->base,
960 refname, extras, skip, err))
961 strbuf_addf(err, "there are still refs under '%s'",
962 refname);
963 goto error_return;
964 }
965 resolved = !!refs_resolve_ref_unsafe(&refs->base,
966 refname, resolve_flags,
967 &lock->old_oid, type);
968 }
969 if (!resolved) {
970 last_errno = errno;
971 if (last_errno != ENOTDIR ||
972 !refs_verify_refname_available(&refs->base, refname,
973 extras, skip, err))
974 strbuf_addf(err, "unable to resolve reference '%s': %s",
975 refname, strerror(last_errno));
976
977 goto error_return;
978 }
979
980 /*
981 * If the ref did not exist and we are creating it, make sure
982 * there is no existing packed ref whose name begins with our
983 * refname, nor a packed ref whose name is a proper prefix of
984 * our refname.
985 */
986 if (is_null_oid(&lock->old_oid) &&
987 refs_verify_refname_available(refs->packed_ref_store, refname,
988 extras, skip, err)) {
989 last_errno = ENOTDIR;
990 goto error_return;
991 }
992
993 lock->ref_name = xstrdup(refname);
994
995 if (raceproof_create_file(ref_file.buf, create_reflock, &lock->lk)) {
996 last_errno = errno;
997 unable_to_lock_message(ref_file.buf, errno, err);
998 goto error_return;
999 }
1000
1001 if (verify_lock(&refs->base, lock, old_oid, mustexist, err)) {
1002 last_errno = errno;
1003 goto error_return;
1004 }
1005 goto out;
1006
1007 error_return:
1008 unlock_ref(lock);
1009 lock = NULL;
1010
1011 out:
1012 strbuf_release(&ref_file);
1013 errno = last_errno;
1014 return lock;
1015 }
1016
1017 struct ref_to_prune {
1018 struct ref_to_prune *next;
1019 struct object_id oid;
1020 char name[FLEX_ARRAY];
1021 };
1022
1023 enum {
1024 REMOVE_EMPTY_PARENTS_REF = 0x01,
1025 REMOVE_EMPTY_PARENTS_REFLOG = 0x02
1026 };
1027
1028 /*
1029 * Remove empty parent directories associated with the specified
1030 * reference and/or its reflog, but spare [logs/]refs/ and immediate
1031 * subdirs. flags is a combination of REMOVE_EMPTY_PARENTS_REF and/or
1032 * REMOVE_EMPTY_PARENTS_REFLOG.
1033 */
1034 static void try_remove_empty_parents(struct files_ref_store *refs,
1035 const char *refname,
1036 unsigned int flags)
1037 {
1038 struct strbuf buf = STRBUF_INIT;
1039 struct strbuf sb = STRBUF_INIT;
1040 char *p, *q;
1041 int i;
1042
1043 strbuf_addstr(&buf, refname);
1044 p = buf.buf;
1045 for (i = 0; i < 2; i++) { /* refs/{heads,tags,...}/ */
1046 while (*p && *p != '/')
1047 p++;
1048 /* tolerate duplicate slashes; see check_refname_format() */
1049 while (*p == '/')
1050 p++;
1051 }
1052 q = buf.buf + buf.len;
1053 while (flags & (REMOVE_EMPTY_PARENTS_REF | REMOVE_EMPTY_PARENTS_REFLOG)) {
1054 while (q > p && *q != '/')
1055 q--;
1056 while (q > p && *(q-1) == '/')
1057 q--;
1058 if (q == p)
1059 break;
1060 strbuf_setlen(&buf, q - buf.buf);
1061
1062 strbuf_reset(&sb);
1063 files_ref_path(refs, &sb, buf.buf);
1064 if ((flags & REMOVE_EMPTY_PARENTS_REF) && rmdir(sb.buf))
1065 flags &= ~REMOVE_EMPTY_PARENTS_REF;
1066
1067 strbuf_reset(&sb);
1068 files_reflog_path(refs, &sb, buf.buf);
1069 if ((flags & REMOVE_EMPTY_PARENTS_REFLOG) && rmdir(sb.buf))
1070 flags &= ~REMOVE_EMPTY_PARENTS_REFLOG;
1071 }
1072 strbuf_release(&buf);
1073 strbuf_release(&sb);
1074 }
1075
1076 /* make sure nobody touched the ref, and unlink */
1077 static void prune_ref(struct files_ref_store *refs, struct ref_to_prune *r)
1078 {
1079 struct ref_transaction *transaction;
1080 struct strbuf err = STRBUF_INIT;
1081 int ret = -1;
1082
1083 if (check_refname_format(r->name, 0))
1084 return;
1085
1086 transaction = ref_store_transaction_begin(&refs->base, &err);
1087 if (!transaction)
1088 goto cleanup;
1089 ref_transaction_add_update(
1090 transaction, r->name,
1091 REF_NO_DEREF | REF_HAVE_NEW | REF_HAVE_OLD | REF_IS_PRUNING,
1092 &null_oid, &r->oid, NULL);
1093 if (ref_transaction_commit(transaction, &err))
1094 goto cleanup;
1095
1096 ret = 0;
1097
1098 cleanup:
1099 if (ret)
1100 error("%s", err.buf);
1101 strbuf_release(&err);
1102 ref_transaction_free(transaction);
1103 return;
1104 }
1105
1106 /*
1107 * Prune the loose versions of the references in the linked list
1108 * `*refs_to_prune`, freeing the entries in the list as we go.
1109 */
1110 static void prune_refs(struct files_ref_store *refs, struct ref_to_prune **refs_to_prune)
1111 {
1112 while (*refs_to_prune) {
1113 struct ref_to_prune *r = *refs_to_prune;
1114 *refs_to_prune = r->next;
1115 prune_ref(refs, r);
1116 free(r);
1117 }
1118 }
1119
1120 /*
1121 * Return true if the specified reference should be packed.
1122 */
1123 static int should_pack_ref(const char *refname,
1124 const struct object_id *oid, unsigned int ref_flags,
1125 unsigned int pack_flags)
1126 {
1127 /* Do not pack per-worktree refs: */
1128 if (ref_type(refname) != REF_TYPE_NORMAL)
1129 return 0;
1130
1131 /* Do not pack non-tags unless PACK_REFS_ALL is set: */
1132 if (!(pack_flags & PACK_REFS_ALL) && !starts_with(refname, "refs/tags/"))
1133 return 0;
1134
1135 /* Do not pack symbolic refs: */
1136 if (ref_flags & REF_ISSYMREF)
1137 return 0;
1138
1139 /* Do not pack broken refs: */
1140 if (!ref_resolves_to_object(refname, oid, ref_flags))
1141 return 0;
1142
1143 return 1;
1144 }
1145
1146 static int files_pack_refs(struct ref_store *ref_store, unsigned int flags)
1147 {
1148 struct files_ref_store *refs =
1149 files_downcast(ref_store, REF_STORE_WRITE | REF_STORE_ODB,
1150 "pack_refs");
1151 struct ref_iterator *iter;
1152 int ok;
1153 struct ref_to_prune *refs_to_prune = NULL;
1154 struct strbuf err = STRBUF_INIT;
1155 struct ref_transaction *transaction;
1156
1157 transaction = ref_store_transaction_begin(refs->packed_ref_store, &err);
1158 if (!transaction)
1159 return -1;
1160
1161 packed_refs_lock(refs->packed_ref_store, LOCK_DIE_ON_ERROR, &err);
1162
1163 iter = cache_ref_iterator_begin(get_loose_ref_cache(refs), NULL, 0);
1164 while ((ok = ref_iterator_advance(iter)) == ITER_OK) {
1165 /*
1166 * If the loose reference can be packed, add an entry
1167 * in the packed ref cache. If the reference should be
1168 * pruned, also add it to refs_to_prune.
1169 */
1170 if (!should_pack_ref(iter->refname, iter->oid, iter->flags,
1171 flags))
1172 continue;
1173
1174 /*
1175 * Add a reference creation for this reference to the
1176 * packed-refs transaction:
1177 */
1178 if (ref_transaction_update(transaction, iter->refname,
1179 iter->oid, NULL,
1180 REF_NO_DEREF, NULL, &err))
1181 die("failure preparing to create packed reference %s: %s",
1182 iter->refname, err.buf);
1183
1184 /* Schedule the loose reference for pruning if requested. */
1185 if ((flags & PACK_REFS_PRUNE)) {
1186 struct ref_to_prune *n;
1187 FLEX_ALLOC_STR(n, name, iter->refname);
1188 oidcpy(&n->oid, iter->oid);
1189 n->next = refs_to_prune;
1190 refs_to_prune = n;
1191 }
1192 }
1193 if (ok != ITER_DONE)
1194 die("error while iterating over references");
1195
1196 if (ref_transaction_commit(transaction, &err))
1197 die("unable to write new packed-refs: %s", err.buf);
1198
1199 ref_transaction_free(transaction);
1200
1201 packed_refs_unlock(refs->packed_ref_store);
1202
1203 prune_refs(refs, &refs_to_prune);
1204 strbuf_release(&err);
1205 return 0;
1206 }
1207
1208 static int files_delete_refs(struct ref_store *ref_store, const char *msg,
1209 struct string_list *refnames, unsigned int flags)
1210 {
1211 struct files_ref_store *refs =
1212 files_downcast(ref_store, REF_STORE_WRITE, "delete_refs");
1213 struct strbuf err = STRBUF_INIT;
1214 int i, result = 0;
1215
1216 if (!refnames->nr)
1217 return 0;
1218
1219 if (packed_refs_lock(refs->packed_ref_store, 0, &err))
1220 goto error;
1221
1222 if (refs_delete_refs(refs->packed_ref_store, msg, refnames, flags)) {
1223 packed_refs_unlock(refs->packed_ref_store);
1224 goto error;
1225 }
1226
1227 packed_refs_unlock(refs->packed_ref_store);
1228
1229 for (i = 0; i < refnames->nr; i++) {
1230 const char *refname = refnames->items[i].string;
1231
1232 if (refs_delete_ref(&refs->base, msg, refname, NULL, flags))
1233 result |= error(_("could not remove reference %s"), refname);
1234 }
1235
1236 strbuf_release(&err);
1237 return result;
1238
1239 error:
1240 /*
1241 * If we failed to rewrite the packed-refs file, then it is
1242 * unsafe to try to remove loose refs, because doing so might
1243 * expose an obsolete packed value for a reference that might
1244 * even point at an object that has been garbage collected.
1245 */
1246 if (refnames->nr == 1)
1247 error(_("could not delete reference %s: %s"),
1248 refnames->items[0].string, err.buf);
1249 else
1250 error(_("could not delete references: %s"), err.buf);
1251
1252 strbuf_release(&err);
1253 return -1;
1254 }
1255
1256 /*
1257 * People using contrib's git-new-workdir have .git/logs/refs ->
1258 * /some/other/path/.git/logs/refs, and that may live on another device.
1259 *
1260 * IOW, to avoid cross device rename errors, the temporary renamed log must
1261 * live into logs/refs.
1262 */
1263 #define TMP_RENAMED_LOG "refs/.tmp-renamed-log"
1264
1265 struct rename_cb {
1266 const char *tmp_renamed_log;
1267 int true_errno;
1268 };
1269
1270 static int rename_tmp_log_callback(const char *path, void *cb_data)
1271 {
1272 struct rename_cb *cb = cb_data;
1273
1274 if (rename(cb->tmp_renamed_log, path)) {
1275 /*
1276 * rename(a, b) when b is an existing directory ought
1277 * to result in ISDIR, but Solaris 5.8 gives ENOTDIR.
1278 * Sheesh. Record the true errno for error reporting,
1279 * but report EISDIR to raceproof_create_file() so
1280 * that it knows to retry.
1281 */
1282 cb->true_errno = errno;
1283 if (errno == ENOTDIR)
1284 errno = EISDIR;
1285 return -1;
1286 } else {
1287 return 0;
1288 }
1289 }
1290
1291 static int rename_tmp_log(struct files_ref_store *refs, const char *newrefname)
1292 {
1293 struct strbuf path = STRBUF_INIT;
1294 struct strbuf tmp = STRBUF_INIT;
1295 struct rename_cb cb;
1296 int ret;
1297
1298 files_reflog_path(refs, &path, newrefname);
1299 files_reflog_path(refs, &tmp, TMP_RENAMED_LOG);
1300 cb.tmp_renamed_log = tmp.buf;
1301 ret = raceproof_create_file(path.buf, rename_tmp_log_callback, &cb);
1302 if (ret) {
1303 if (errno == EISDIR)
1304 error("directory not empty: %s", path.buf);
1305 else
1306 error("unable to move logfile %s to %s: %s",
1307 tmp.buf, path.buf,
1308 strerror(cb.true_errno));
1309 }
1310
1311 strbuf_release(&path);
1312 strbuf_release(&tmp);
1313 return ret;
1314 }
1315
1316 static int write_ref_to_lockfile(struct ref_lock *lock,
1317 const struct object_id *oid, struct strbuf *err);
1318 static int commit_ref_update(struct files_ref_store *refs,
1319 struct ref_lock *lock,
1320 const struct object_id *oid, const char *logmsg,
1321 struct strbuf *err);
1322
1323 static int files_copy_or_rename_ref(struct ref_store *ref_store,
1324 const char *oldrefname, const char *newrefname,
1325 const char *logmsg, int copy)
1326 {
1327 struct files_ref_store *refs =
1328 files_downcast(ref_store, REF_STORE_WRITE, "rename_ref");
1329 struct object_id orig_oid;
1330 int flag = 0, logmoved = 0;
1331 struct ref_lock *lock;
1332 struct stat loginfo;
1333 struct strbuf sb_oldref = STRBUF_INIT;
1334 struct strbuf sb_newref = STRBUF_INIT;
1335 struct strbuf tmp_renamed_log = STRBUF_INIT;
1336 int log, ret;
1337 struct strbuf err = STRBUF_INIT;
1338
1339 files_reflog_path(refs, &sb_oldref, oldrefname);
1340 files_reflog_path(refs, &sb_newref, newrefname);
1341 files_reflog_path(refs, &tmp_renamed_log, TMP_RENAMED_LOG);
1342
1343 log = !lstat(sb_oldref.buf, &loginfo);
1344 if (log && S_ISLNK(loginfo.st_mode)) {
1345 ret = error("reflog for %s is a symlink", oldrefname);
1346 goto out;
1347 }
1348
1349 if (!refs_resolve_ref_unsafe(&refs->base, oldrefname,
1350 RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
1351 &orig_oid, &flag)) {
1352 ret = error("refname %s not found", oldrefname);
1353 goto out;
1354 }
1355
1356 if (flag & REF_ISSYMREF) {
1357 if (copy)
1358 ret = error("refname %s is a symbolic ref, copying it is not supported",
1359 oldrefname);
1360 else
1361 ret = error("refname %s is a symbolic ref, renaming it is not supported",
1362 oldrefname);
1363 goto out;
1364 }
1365 if (!refs_rename_ref_available(&refs->base, oldrefname, newrefname)) {
1366 ret = 1;
1367 goto out;
1368 }
1369
1370 if (!copy && log && rename(sb_oldref.buf, tmp_renamed_log.buf)) {
1371 ret = error("unable to move logfile logs/%s to logs/"TMP_RENAMED_LOG": %s",
1372 oldrefname, strerror(errno));
1373 goto out;
1374 }
1375
1376 if (copy && log && copy_file(tmp_renamed_log.buf, sb_oldref.buf, 0644)) {
1377 ret = error("unable to copy logfile logs/%s to logs/"TMP_RENAMED_LOG": %s",
1378 oldrefname, strerror(errno));
1379 goto out;
1380 }
1381
1382 if (!copy && refs_delete_ref(&refs->base, logmsg, oldrefname,
1383 &orig_oid, REF_NO_DEREF)) {
1384 error("unable to delete old %s", oldrefname);
1385 goto rollback;
1386 }
1387
1388 /*
1389 * Since we are doing a shallow lookup, oid is not the
1390 * correct value to pass to delete_ref as old_oid. But that
1391 * doesn't matter, because an old_oid check wouldn't add to
1392 * the safety anyway; we want to delete the reference whatever
1393 * its current value.
1394 */
1395 if (!copy && !refs_read_ref_full(&refs->base, newrefname,
1396 RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
1397 NULL, NULL) &&
1398 refs_delete_ref(&refs->base, NULL, newrefname,
1399 NULL, REF_NO_DEREF)) {
1400 if (errno == EISDIR) {
1401 struct strbuf path = STRBUF_INIT;
1402 int result;
1403
1404 files_ref_path(refs, &path, newrefname);
1405 result = remove_empty_directories(&path);
1406 strbuf_release(&path);
1407
1408 if (result) {
1409 error("Directory not empty: %s", newrefname);
1410 goto rollback;
1411 }
1412 } else {
1413 error("unable to delete existing %s", newrefname);
1414 goto rollback;
1415 }
1416 }
1417
1418 if (log && rename_tmp_log(refs, newrefname))
1419 goto rollback;
1420
1421 logmoved = log;
1422
1423 lock = lock_ref_oid_basic(refs, newrefname, NULL, NULL, NULL,
1424 REF_NO_DEREF, NULL, &err);
1425 if (!lock) {
1426 if (copy)
1427 error("unable to copy '%s' to '%s': %s", oldrefname, newrefname, err.buf);
1428 else
1429 error("unable to rename '%s' to '%s': %s", oldrefname, newrefname, err.buf);
1430 strbuf_release(&err);
1431 goto rollback;
1432 }
1433 oidcpy(&lock->old_oid, &orig_oid);
1434
1435 if (write_ref_to_lockfile(lock, &orig_oid, &err) ||
1436 commit_ref_update(refs, lock, &orig_oid, logmsg, &err)) {
1437 error("unable to write current sha1 into %s: %s", newrefname, err.buf);
1438 strbuf_release(&err);
1439 goto rollback;
1440 }
1441
1442 ret = 0;
1443 goto out;
1444
1445 rollback:
1446 lock = lock_ref_oid_basic(refs, oldrefname, NULL, NULL, NULL,
1447 REF_NO_DEREF, NULL, &err);
1448 if (!lock) {
1449 error("unable to lock %s for rollback: %s", oldrefname, err.buf);
1450 strbuf_release(&err);
1451 goto rollbacklog;
1452 }
1453
1454 flag = log_all_ref_updates;
1455 log_all_ref_updates = LOG_REFS_NONE;
1456 if (write_ref_to_lockfile(lock, &orig_oid, &err) ||
1457 commit_ref_update(refs, lock, &orig_oid, NULL, &err)) {
1458 error("unable to write current sha1 into %s: %s", oldrefname, err.buf);
1459 strbuf_release(&err);
1460 }
1461 log_all_ref_updates = flag;
1462
1463 rollbacklog:
1464 if (logmoved && rename(sb_newref.buf, sb_oldref.buf))
1465 error("unable to restore logfile %s from %s: %s",
1466 oldrefname, newrefname, strerror(errno));
1467 if (!logmoved && log &&
1468 rename(tmp_renamed_log.buf, sb_oldref.buf))
1469 error("unable to restore logfile %s from logs/"TMP_RENAMED_LOG": %s",
1470 oldrefname, strerror(errno));
1471 ret = 1;
1472 out:
1473 strbuf_release(&sb_newref);
1474 strbuf_release(&sb_oldref);
1475 strbuf_release(&tmp_renamed_log);
1476
1477 return ret;
1478 }
1479
1480 static int files_rename_ref(struct ref_store *ref_store,
1481 const char *oldrefname, const char *newrefname,
1482 const char *logmsg)
1483 {
1484 return files_copy_or_rename_ref(ref_store, oldrefname,
1485 newrefname, logmsg, 0);
1486 }
1487
1488 static int files_copy_ref(struct ref_store *ref_store,
1489 const char *oldrefname, const char *newrefname,
1490 const char *logmsg)
1491 {
1492 return files_copy_or_rename_ref(ref_store, oldrefname,
1493 newrefname, logmsg, 1);
1494 }
1495
1496 static int close_ref_gently(struct ref_lock *lock)
1497 {
1498 if (close_lock_file_gently(&lock->lk))
1499 return -1;
1500 return 0;
1501 }
1502
1503 static int commit_ref(struct ref_lock *lock)
1504 {
1505 char *path = get_locked_file_path(&lock->lk);
1506 struct stat st;
1507
1508 if (!lstat(path, &st) && S_ISDIR(st.st_mode)) {
1509 /*
1510 * There is a directory at the path we want to rename
1511 * the lockfile to. Hopefully it is empty; try to
1512 * delete it.
1513 */
1514 size_t len = strlen(path);
1515 struct strbuf sb_path = STRBUF_INIT;
1516
1517 strbuf_attach(&sb_path, path, len, len);
1518
1519 /*
1520 * If this fails, commit_lock_file() will also fail
1521 * and will report the problem.
1522 */
1523 remove_empty_directories(&sb_path);
1524 strbuf_release(&sb_path);
1525 } else {
1526 free(path);
1527 }
1528
1529 if (commit_lock_file(&lock->lk))
1530 return -1;
1531 return 0;
1532 }
1533
1534 static int open_or_create_logfile(const char *path, void *cb)
1535 {
1536 int *fd = cb;
1537
1538 *fd = open(path, O_APPEND | O_WRONLY | O_CREAT, 0666);
1539 return (*fd < 0) ? -1 : 0;
1540 }
1541
1542 /*
1543 * Create a reflog for a ref. If force_create = 0, only create the
1544 * reflog for certain refs (those for which should_autocreate_reflog
1545 * returns non-zero). Otherwise, create it regardless of the reference
1546 * name. If the logfile already existed or was created, return 0 and
1547 * set *logfd to the file descriptor opened for appending to the file.
1548 * If no logfile exists and we decided not to create one, return 0 and
1549 * set *logfd to -1. On failure, fill in *err, set *logfd to -1, and
1550 * return -1.
1551 */
1552 static int log_ref_setup(struct files_ref_store *refs,
1553 const char *refname, int force_create,
1554 int *logfd, struct strbuf *err)
1555 {
1556 struct strbuf logfile_sb = STRBUF_INIT;
1557 char *logfile;
1558
1559 files_reflog_path(refs, &logfile_sb, refname);
1560 logfile = strbuf_detach(&logfile_sb, NULL);
1561
1562 if (force_create || should_autocreate_reflog(refname)) {
1563 if (raceproof_create_file(logfile, open_or_create_logfile, logfd)) {
1564 if (errno == ENOENT)
1565 strbuf_addf(err, "unable to create directory for '%s': "
1566 "%s", logfile, strerror(errno));
1567 else if (errno == EISDIR)
1568 strbuf_addf(err, "there are still logs under '%s'",
1569 logfile);
1570 else
1571 strbuf_addf(err, "unable to append to '%s': %s",
1572 logfile, strerror(errno));
1573
1574 goto error;
1575 }
1576 } else {
1577 *logfd = open(logfile, O_APPEND | O_WRONLY, 0666);
1578 if (*logfd < 0) {
1579 if (errno == ENOENT || errno == EISDIR) {
1580 /*
1581 * The logfile doesn't already exist,
1582 * but that is not an error; it only
1583 * means that we won't write log
1584 * entries to it.
1585 */
1586 ;
1587 } else {
1588 strbuf_addf(err, "unable to append to '%s': %s",
1589 logfile, strerror(errno));
1590 goto error;
1591 }
1592 }
1593 }
1594
1595 if (*logfd >= 0)
1596 adjust_shared_perm(logfile);
1597
1598 free(logfile);
1599 return 0;
1600
1601 error:
1602 free(logfile);
1603 return -1;
1604 }
1605
1606 static int files_create_reflog(struct ref_store *ref_store,
1607 const char *refname, int force_create,
1608 struct strbuf *err)
1609 {
1610 struct files_ref_store *refs =
1611 files_downcast(ref_store, REF_STORE_WRITE, "create_reflog");
1612 int fd;
1613
1614 if (log_ref_setup(refs, refname, force_create, &fd, err))
1615 return -1;
1616
1617 if (fd >= 0)
1618 close(fd);
1619
1620 return 0;
1621 }
1622
1623 static int log_ref_write_fd(int fd, const struct object_id *old_oid,
1624 const struct object_id *new_oid,
1625 const char *committer, const char *msg)
1626 {
1627 struct strbuf sb = STRBUF_INIT;
1628 int ret = 0;
1629
1630 strbuf_addf(&sb, "%s %s %s", oid_to_hex(old_oid), oid_to_hex(new_oid), committer);
1631 if (msg && *msg)
1632 copy_reflog_msg(&sb, msg);
1633 strbuf_addch(&sb, '\n');
1634 if (write_in_full(fd, sb.buf, sb.len) < 0)
1635 ret = -1;
1636 strbuf_release(&sb);
1637 return ret;
1638 }
1639
1640 static int files_log_ref_write(struct files_ref_store *refs,
1641 const char *refname, const struct object_id *old_oid,
1642 const struct object_id *new_oid, const char *msg,
1643 int flags, struct strbuf *err)
1644 {
1645 int logfd, result;
1646
1647 if (log_all_ref_updates == LOG_REFS_UNSET)
1648 log_all_ref_updates = is_bare_repository() ? LOG_REFS_NONE : LOG_REFS_NORMAL;
1649
1650 result = log_ref_setup(refs, refname,
1651 flags & REF_FORCE_CREATE_REFLOG,
1652 &logfd, err);
1653
1654 if (result)
1655 return result;
1656
1657 if (logfd < 0)
1658 return 0;
1659 result = log_ref_write_fd(logfd, old_oid, new_oid,
1660 git_committer_info(0), msg);
1661 if (result) {
1662 struct strbuf sb = STRBUF_INIT;
1663 int save_errno = errno;
1664
1665 files_reflog_path(refs, &sb, refname);
1666 strbuf_addf(err, "unable to append to '%s': %s",
1667 sb.buf, strerror(save_errno));
1668 strbuf_release(&sb);
1669 close(logfd);
1670 return -1;
1671 }
1672 if (close(logfd)) {
1673 struct strbuf sb = STRBUF_INIT;
1674 int save_errno = errno;
1675
1676 files_reflog_path(refs, &sb, refname);
1677 strbuf_addf(err, "unable to append to '%s': %s",
1678 sb.buf, strerror(save_errno));
1679 strbuf_release(&sb);
1680 return -1;
1681 }
1682 return 0;
1683 }
1684
1685 /*
1686 * Write oid into the open lockfile, then close the lockfile. On
1687 * errors, rollback the lockfile, fill in *err and return -1.
1688 */
1689 static int write_ref_to_lockfile(struct ref_lock *lock,
1690 const struct object_id *oid, struct strbuf *err)
1691 {
1692 static char term = '\n';
1693 struct object *o;
1694 int fd;
1695
1696 o = parse_object(the_repository, oid);
1697 if (!o) {
1698 strbuf_addf(err,
1699 "trying to write ref '%s' with nonexistent object %s",
1700 lock->ref_name, oid_to_hex(oid));
1701 unlock_ref(lock);
1702 return -1;
1703 }
1704 if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
1705 strbuf_addf(err,
1706 "trying to write non-commit object %s to branch '%s'",
1707 oid_to_hex(oid), lock->ref_name);
1708 unlock_ref(lock);
1709 return -1;
1710 }
1711 fd = get_lock_file_fd(&lock->lk);
1712 if (write_in_full(fd, oid_to_hex(oid), the_hash_algo->hexsz) < 0 ||
1713 write_in_full(fd, &term, 1) < 0 ||
1714 close_ref_gently(lock) < 0) {
1715 strbuf_addf(err,
1716 "couldn't write '%s'", get_lock_file_path(&lock->lk));
1717 unlock_ref(lock);
1718 return -1;
1719 }
1720 return 0;
1721 }
1722
1723 /*
1724 * Commit a change to a loose reference that has already been written
1725 * to the loose reference lockfile. Also update the reflogs if
1726 * necessary, using the specified lockmsg (which can be NULL).
1727 */
1728 static int commit_ref_update(struct files_ref_store *refs,
1729 struct ref_lock *lock,
1730 const struct object_id *oid, const char *logmsg,
1731 struct strbuf *err)
1732 {
1733 files_assert_main_repository(refs, "commit_ref_update");
1734
1735 clear_loose_ref_cache(refs);
1736 if (files_log_ref_write(refs, lock->ref_name,
1737 &lock->old_oid, oid,
1738 logmsg, 0, err)) {
1739 char *old_msg = strbuf_detach(err, NULL);
1740 strbuf_addf(err, "cannot update the ref '%s': %s",
1741 lock->ref_name, old_msg);
1742 free(old_msg);
1743 unlock_ref(lock);
1744 return -1;
1745 }
1746
1747 if (strcmp(lock->ref_name, "HEAD") != 0) {
1748 /*
1749 * Special hack: If a branch is updated directly and HEAD
1750 * points to it (may happen on the remote side of a push
1751 * for example) then logically the HEAD reflog should be
1752 * updated too.
1753 * A generic solution implies reverse symref information,
1754 * but finding all symrefs pointing to the given branch
1755 * would be rather costly for this rare event (the direct
1756 * update of a branch) to be worth it. So let's cheat and
1757 * check with HEAD only which should cover 99% of all usage
1758 * scenarios (even 100% of the default ones).
1759 */
1760 int head_flag;
1761 const char *head_ref;
1762
1763 head_ref = refs_resolve_ref_unsafe(&refs->base, "HEAD",
1764 RESOLVE_REF_READING,
1765 NULL, &head_flag);
1766 if (head_ref && (head_flag & REF_ISSYMREF) &&
1767 !strcmp(head_ref, lock->ref_name)) {
1768 struct strbuf log_err = STRBUF_INIT;
1769 if (files_log_ref_write(refs, "HEAD",
1770 &lock->old_oid, oid,
1771 logmsg, 0, &log_err)) {
1772 error("%s", log_err.buf);
1773 strbuf_release(&log_err);
1774 }
1775 }
1776 }
1777
1778 if (commit_ref(lock)) {
1779 strbuf_addf(err, "couldn't set '%s'", lock->ref_name);
1780 unlock_ref(lock);
1781 return -1;
1782 }
1783
1784 unlock_ref(lock);
1785 return 0;
1786 }
1787
1788 static int create_ref_symlink(struct ref_lock *lock, const char *target)
1789 {
1790 int ret = -1;
1791 #ifndef NO_SYMLINK_HEAD
1792 char *ref_path = get_locked_file_path(&lock->lk);
1793 unlink(ref_path);
1794 ret = symlink(target, ref_path);
1795 free(ref_path);
1796
1797 if (ret)
1798 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
1799 #endif
1800 return ret;
1801 }
1802
1803 static void update_symref_reflog(struct files_ref_store *refs,
1804 struct ref_lock *lock, const char *refname,
1805 const char *target, const char *logmsg)
1806 {
1807 struct strbuf err = STRBUF_INIT;
1808 struct object_id new_oid;
1809 if (logmsg &&
1810 !refs_read_ref_full(&refs->base, target,
1811 RESOLVE_REF_READING, &new_oid, NULL) &&
1812 files_log_ref_write(refs, refname, &lock->old_oid,
1813 &new_oid, logmsg, 0, &err)) {
1814 error("%s", err.buf);
1815 strbuf_release(&err);
1816 }
1817 }
1818
1819 static int create_symref_locked(struct files_ref_store *refs,
1820 struct ref_lock *lock, const char *refname,
1821 const char *target, const char *logmsg)
1822 {
1823 if (prefer_symlink_refs && !create_ref_symlink(lock, target)) {
1824 update_symref_reflog(refs, lock, refname, target, logmsg);
1825 return 0;
1826 }
1827
1828 if (!fdopen_lock_file(&lock->lk, "w"))
1829 return error("unable to fdopen %s: %s",
1830 lock->lk.tempfile->filename.buf, strerror(errno));
1831
1832 update_symref_reflog(refs, lock, refname, target, logmsg);
1833
1834 /* no error check; commit_ref will check ferror */
1835 fprintf(lock->lk.tempfile->fp, "ref: %s\n", target);
1836 if (commit_ref(lock) < 0)
1837 return error("unable to write symref for %s: %s", refname,
1838 strerror(errno));
1839 return 0;
1840 }
1841
1842 static int files_create_symref(struct ref_store *ref_store,
1843 const char *refname, const char *target,
1844 const char *logmsg)
1845 {
1846 struct files_ref_store *refs =
1847 files_downcast(ref_store, REF_STORE_WRITE, "create_symref");
1848 struct strbuf err = STRBUF_INIT;
1849 struct ref_lock *lock;
1850 int ret;
1851
1852 lock = lock_ref_oid_basic(refs, refname, NULL,
1853 NULL, NULL, REF_NO_DEREF, NULL,
1854 &err);
1855 if (!lock) {
1856 error("%s", err.buf);
1857 strbuf_release(&err);
1858 return -1;
1859 }
1860
1861 ret = create_symref_locked(refs, lock, refname, target, logmsg);
1862 unlock_ref(lock);
1863 return ret;
1864 }
1865
1866 static int files_reflog_exists(struct ref_store *ref_store,
1867 const char *refname)
1868 {
1869 struct files_ref_store *refs =
1870 files_downcast(ref_store, REF_STORE_READ, "reflog_exists");
1871 struct strbuf sb = STRBUF_INIT;
1872 struct stat st;
1873 int ret;
1874
1875 files_reflog_path(refs, &sb, refname);
1876 ret = !lstat(sb.buf, &st) && S_ISREG(st.st_mode);
1877 strbuf_release(&sb);
1878 return ret;
1879 }
1880
1881 static int files_delete_reflog(struct ref_store *ref_store,
1882 const char *refname)
1883 {
1884 struct files_ref_store *refs =
1885 files_downcast(ref_store, REF_STORE_WRITE, "delete_reflog");
1886 struct strbuf sb = STRBUF_INIT;
1887 int ret;
1888
1889 files_reflog_path(refs, &sb, refname);
1890 ret = remove_path(sb.buf);
1891 strbuf_release(&sb);
1892 return ret;
1893 }
1894
1895 static int show_one_reflog_ent(struct strbuf *sb, each_reflog_ent_fn fn, void *cb_data)
1896 {
1897 struct object_id ooid, noid;
1898 char *email_end, *message;
1899 timestamp_t timestamp;
1900 int tz;
1901 const char *p = sb->buf;
1902
1903 /* old SP new SP name <email> SP time TAB msg LF */
1904 if (!sb->len || sb->buf[sb->len - 1] != '\n' ||
1905 parse_oid_hex(p, &ooid, &p) || *p++ != ' ' ||
1906 parse_oid_hex(p, &noid, &p) || *p++ != ' ' ||
1907 !(email_end = strchr(p, '>')) ||
1908 email_end[1] != ' ' ||
1909 !(timestamp = parse_timestamp(email_end + 2, &message, 10)) ||
1910 !message || message[0] != ' ' ||
1911 (message[1] != '+' && message[1] != '-') ||
1912 !isdigit(message[2]) || !isdigit(message[3]) ||
1913 !isdigit(message[4]) || !isdigit(message[5]))
1914 return 0; /* corrupt? */
1915 email_end[1] = '\0';
1916 tz = strtol(message + 1, NULL, 10);
1917 if (message[6] != '\t')
1918 message += 6;
1919 else
1920 message += 7;
1921 return fn(&ooid, &noid, p, timestamp, tz, message, cb_data);
1922 }
1923
1924 static char *find_beginning_of_line(char *bob, char *scan)
1925 {
1926 while (bob < scan && *(--scan) != '\n')
1927 ; /* keep scanning backwards */
1928 /*
1929 * Return either beginning of the buffer, or LF at the end of
1930 * the previous line.
1931 */
1932 return scan;
1933 }
1934
1935 static int files_for_each_reflog_ent_reverse(struct ref_store *ref_store,
1936 const char *refname,
1937 each_reflog_ent_fn fn,
1938 void *cb_data)
1939 {
1940 struct files_ref_store *refs =
1941 files_downcast(ref_store, REF_STORE_READ,
1942 "for_each_reflog_ent_reverse");
1943 struct strbuf sb = STRBUF_INIT;
1944 FILE *logfp;
1945 long pos;
1946 int ret = 0, at_tail = 1;
1947
1948 files_reflog_path(refs, &sb, refname);
1949 logfp = fopen(sb.buf, "r");
1950 strbuf_release(&sb);
1951 if (!logfp)
1952 return -1;
1953
1954 /* Jump to the end */
1955 if (fseek(logfp, 0, SEEK_END) < 0)
1956 ret = error("cannot seek back reflog for %s: %s",
1957 refname, strerror(errno));
1958 pos = ftell(logfp);
1959 while (!ret && 0 < pos) {
1960 int cnt;
1961 size_t nread;
1962 char buf[BUFSIZ];
1963 char *endp, *scanp;
1964
1965 /* Fill next block from the end */
1966 cnt = (sizeof(buf) < pos) ? sizeof(buf) : pos;
1967 if (fseek(logfp, pos - cnt, SEEK_SET)) {
1968 ret = error("cannot seek back reflog for %s: %s",
1969 refname, strerror(errno));
1970 break;
1971 }
1972 nread = fread(buf, cnt, 1, logfp);
1973 if (nread != 1) {
1974 ret = error("cannot read %d bytes from reflog for %s: %s",
1975 cnt, refname, strerror(errno));
1976 break;
1977 }
1978 pos -= cnt;
1979
1980 scanp = endp = buf + cnt;
1981 if (at_tail && scanp[-1] == '\n')
1982 /* Looking at the final LF at the end of the file */
1983 scanp--;
1984 at_tail = 0;
1985
1986 while (buf < scanp) {
1987 /*
1988 * terminating LF of the previous line, or the beginning
1989 * of the buffer.
1990 */
1991 char *bp;
1992
1993 bp = find_beginning_of_line(buf, scanp);
1994
1995 if (*bp == '\n') {
1996 /*
1997 * The newline is the end of the previous line,
1998 * so we know we have complete line starting
1999 * at (bp + 1). Prefix it onto any prior data
2000 * we collected for the line and process it.
2001 */
2002 strbuf_splice(&sb, 0, 0, bp + 1, endp - (bp + 1));
2003 scanp = bp;
2004 endp = bp + 1;
2005 ret = show_one_reflog_ent(&sb, fn, cb_data);
2006 strbuf_reset(&sb);
2007 if (ret)
2008 break;
2009 } else if (!pos) {
2010 /*
2011 * We are at the start of the buffer, and the
2012 * start of the file; there is no previous
2013 * line, and we have everything for this one.
2014 * Process it, and we can end the loop.
2015 */
2016 strbuf_splice(&sb, 0, 0, buf, endp - buf);
2017 ret = show_one_reflog_ent(&sb, fn, cb_data);
2018 strbuf_reset(&sb);
2019 break;
2020 }
2021
2022 if (bp == buf) {
2023 /*
2024 * We are at the start of the buffer, and there
2025 * is more file to read backwards. Which means
2026 * we are in the middle of a line. Note that we
2027 * may get here even if *bp was a newline; that
2028 * just means we are at the exact end of the
2029 * previous line, rather than some spot in the
2030 * middle.
2031 *
2032 * Save away what we have to be combined with
2033 * the data from the next read.
2034 */
2035 strbuf_splice(&sb, 0, 0, buf, endp - buf);
2036 break;
2037 }
2038 }
2039
2040 }
2041 if (!ret && sb.len)
2042 BUG("reverse reflog parser had leftover data");
2043
2044 fclose(logfp);
2045 strbuf_release(&sb);
2046 return ret;
2047 }
2048
2049 static int files_for_each_reflog_ent(struct ref_store *ref_store,
2050 const char *refname,
2051 each_reflog_ent_fn fn, void *cb_data)
2052 {
2053 struct files_ref_store *refs =
2054 files_downcast(ref_store, REF_STORE_READ,
2055 "for_each_reflog_ent");
2056 FILE *logfp;
2057 struct strbuf sb = STRBUF_INIT;
2058 int ret = 0;
2059
2060 files_reflog_path(refs, &sb, refname);
2061 logfp = fopen(sb.buf, "r");
2062 strbuf_release(&sb);
2063 if (!logfp)
2064 return -1;
2065
2066 while (!ret && !strbuf_getwholeline(&sb, logfp, '\n'))
2067 ret = show_one_reflog_ent(&sb, fn, cb_data);
2068 fclose(logfp);
2069 strbuf_release(&sb);
2070 return ret;
2071 }
2072
2073 struct files_reflog_iterator {
2074 struct ref_iterator base;
2075
2076 struct ref_store *ref_store;
2077 struct dir_iterator *dir_iterator;
2078 struct object_id oid;
2079 };
2080
2081 static int files_reflog_iterator_advance(struct ref_iterator *ref_iterator)
2082 {
2083 struct files_reflog_iterator *iter =
2084 (struct files_reflog_iterator *)ref_iterator;
2085 struct dir_iterator *diter = iter->dir_iterator;
2086 int ok;
2087
2088 while ((ok = dir_iterator_advance(diter)) == ITER_OK) {
2089 int flags;
2090
2091 if (!S_ISREG(diter->st.st_mode))
2092 continue;
2093 if (diter->basename[0] == '.')
2094 continue;
2095 if (ends_with(diter->basename, ".lock"))
2096 continue;
2097
2098 if (refs_read_ref_full(iter->ref_store,
2099 diter->relative_path, 0,
2100 &iter->oid, &flags)) {
2101 error("bad ref for %s", diter->path.buf);
2102 continue;
2103 }
2104
2105 iter->base.refname = diter->relative_path;
2106 iter->base.oid = &iter->oid;
2107 iter->base.flags = flags;
2108 return ITER_OK;
2109 }
2110
2111 iter->dir_iterator = NULL;
2112 if (ref_iterator_abort(ref_iterator) == ITER_ERROR)
2113 ok = ITER_ERROR;
2114 return ok;
2115 }
2116
2117 static int files_reflog_iterator_peel(struct ref_iterator *ref_iterator,
2118 struct object_id *peeled)
2119 {
2120 BUG("ref_iterator_peel() called for reflog_iterator");
2121 }
2122
2123 static int files_reflog_iterator_abort(struct ref_iterator *ref_iterator)
2124 {
2125 struct files_reflog_iterator *iter =
2126 (struct files_reflog_iterator *)ref_iterator;
2127 int ok = ITER_DONE;
2128
2129 if (iter->dir_iterator)
2130 ok = dir_iterator_abort(iter->dir_iterator);
2131
2132 base_ref_iterator_free(ref_iterator);
2133 return ok;
2134 }
2135
2136 static struct ref_iterator_vtable files_reflog_iterator_vtable = {
2137 files_reflog_iterator_advance,
2138 files_reflog_iterator_peel,
2139 files_reflog_iterator_abort
2140 };
2141
2142 static struct ref_iterator *reflog_iterator_begin(struct ref_store *ref_store,
2143 const char *gitdir)
2144 {
2145 struct dir_iterator *diter;
2146 struct files_reflog_iterator *iter;
2147 struct ref_iterator *ref_iterator;
2148 struct strbuf sb = STRBUF_INIT;
2149
2150 strbuf_addf(&sb, "%s/logs", gitdir);
2151
2152 diter = dir_iterator_begin(sb.buf, 0);
2153 if (!diter) {
2154 strbuf_release(&sb);
2155 return empty_ref_iterator_begin();
2156 }
2157
2158 iter = xcalloc(1, sizeof(*iter));
2159 ref_iterator = &iter->base;
2160
2161 base_ref_iterator_init(ref_iterator, &files_reflog_iterator_vtable, 0);
2162 iter->dir_iterator = diter;
2163 iter->ref_store = ref_store;
2164 strbuf_release(&sb);
2165
2166 return ref_iterator;
2167 }
2168
2169 static enum iterator_selection reflog_iterator_select(
2170 struct ref_iterator *iter_worktree,
2171 struct ref_iterator *iter_common,
2172 void *cb_data)
2173 {
2174 if (iter_worktree) {
2175 /*
2176 * We're a bit loose here. We probably should ignore
2177 * common refs if they are accidentally added as
2178 * per-worktree refs.
2179 */
2180 return ITER_SELECT_0;
2181 } else if (iter_common) {
2182 if (ref_type(iter_common->refname) == REF_TYPE_NORMAL)
2183 return ITER_SELECT_1;
2184
2185 /*
2186 * The main ref store may contain main worktree's
2187 * per-worktree refs, which should be ignored
2188 */
2189 return ITER_SKIP_1;
2190 } else
2191 return ITER_DONE;
2192 }
2193
2194 static struct ref_iterator *files_reflog_iterator_begin(struct ref_store *ref_store)
2195 {
2196 struct files_ref_store *refs =
2197 files_downcast(ref_store, REF_STORE_READ,
2198 "reflog_iterator_begin");
2199
2200 if (!strcmp(refs->gitdir, refs->gitcommondir)) {
2201 return reflog_iterator_begin(ref_store, refs->gitcommondir);
2202 } else {
2203 return merge_ref_iterator_begin(
2204 0,
2205 reflog_iterator_begin(ref_store, refs->gitdir),
2206 reflog_iterator_begin(ref_store, refs->gitcommondir),
2207 reflog_iterator_select, refs);
2208 }
2209 }
2210
2211 /*
2212 * If update is a direct update of head_ref (the reference pointed to
2213 * by HEAD), then add an extra REF_LOG_ONLY update for HEAD.
2214 */
2215 static int split_head_update(struct ref_update *update,
2216 struct ref_transaction *transaction,
2217 const char *head_ref,
2218 struct string_list *affected_refnames,
2219 struct strbuf *err)
2220 {
2221 struct string_list_item *item;
2222 struct ref_update *new_update;
2223
2224 if ((update->flags & REF_LOG_ONLY) ||
2225 (update->flags & REF_IS_PRUNING) ||
2226 (update->flags & REF_UPDATE_VIA_HEAD))
2227 return 0;
2228
2229 if (strcmp(update->refname, head_ref))
2230 return 0;
2231
2232 /*
2233 * First make sure that HEAD is not already in the
2234 * transaction. This check is O(lg N) in the transaction
2235 * size, but it happens at most once per transaction.
2236 */
2237 if (string_list_has_string(affected_refnames, "HEAD")) {
2238 /* An entry already existed */
2239 strbuf_addf(err,
2240 "multiple updates for 'HEAD' (including one "
2241 "via its referent '%s') are not allowed",
2242 update->refname);
2243 return TRANSACTION_NAME_CONFLICT;
2244 }
2245
2246 new_update = ref_transaction_add_update(
2247 transaction, "HEAD",
2248 update->flags | REF_LOG_ONLY | REF_NO_DEREF,
2249 &update->new_oid, &update->old_oid,
2250 update->msg);
2251
2252 /*
2253 * Add "HEAD". This insertion is O(N) in the transaction
2254 * size, but it happens at most once per transaction.
2255 * Add new_update->refname instead of a literal "HEAD".
2256 */
2257 if (strcmp(new_update->refname, "HEAD"))
2258 BUG("%s unexpectedly not 'HEAD'", new_update->refname);
2259 item = string_list_insert(affected_refnames, new_update->refname);
2260 item->util = new_update;
2261
2262 return 0;
2263 }
2264
2265 /*
2266 * update is for a symref that points at referent and doesn't have
2267 * REF_NO_DEREF set. Split it into two updates:
2268 * - The original update, but with REF_LOG_ONLY and REF_NO_DEREF set
2269 * - A new, separate update for the referent reference
2270 * Note that the new update will itself be subject to splitting when
2271 * the iteration gets to it.
2272 */
2273 static int split_symref_update(struct ref_update *update,
2274 const char *referent,
2275 struct ref_transaction *transaction,
2276 struct string_list *affected_refnames,
2277 struct strbuf *err)
2278 {
2279 struct string_list_item *item;
2280 struct ref_update *new_update;
2281 unsigned int new_flags;
2282
2283 /*
2284 * First make sure that referent is not already in the
2285 * transaction. This check is O(lg N) in the transaction
2286 * size, but it happens at most once per symref in a
2287 * transaction.
2288 */
2289 if (string_list_has_string(affected_refnames, referent)) {
2290 /* An entry already exists */
2291 strbuf_addf(err,
2292 "multiple updates for '%s' (including one "
2293 "via symref '%s') are not allowed",
2294 referent, update->refname);
2295 return TRANSACTION_NAME_CONFLICT;
2296 }
2297
2298 new_flags = update->flags;
2299 if (!strcmp(update->refname, "HEAD")) {
2300 /*
2301 * Record that the new update came via HEAD, so that
2302 * when we process it, split_head_update() doesn't try
2303 * to add another reflog update for HEAD. Note that
2304 * this bit will be propagated if the new_update
2305 * itself needs to be split.
2306 */
2307 new_flags |= REF_UPDATE_VIA_HEAD;
2308 }
2309
2310 new_update = ref_transaction_add_update(
2311 transaction, referent, new_flags,
2312 &update->new_oid, &update->old_oid,
2313 update->msg);
2314
2315 new_update->parent_update = update;
2316
2317 /*
2318 * Change the symbolic ref update to log only. Also, it
2319 * doesn't need to check its old OID value, as that will be
2320 * done when new_update is processed.
2321 */
2322 update->flags |= REF_LOG_ONLY | REF_NO_DEREF;
2323 update->flags &= ~REF_HAVE_OLD;
2324
2325 /*
2326 * Add the referent. This insertion is O(N) in the transaction
2327 * size, but it happens at most once per symref in a
2328 * transaction. Make sure to add new_update->refname, which will
2329 * be valid as long as affected_refnames is in use, and NOT
2330 * referent, which might soon be freed by our caller.
2331 */
2332 item = string_list_insert(affected_refnames, new_update->refname);
2333 if (item->util)
2334 BUG("%s unexpectedly found in affected_refnames",
2335 new_update->refname);
2336 item->util = new_update;
2337
2338 return 0;
2339 }
2340
2341 /*
2342 * Return the refname under which update was originally requested.
2343 */
2344 static const char *original_update_refname(struct ref_update *update)
2345 {
2346 while (update->parent_update)
2347 update = update->parent_update;
2348
2349 return update->refname;
2350 }
2351
2352 /*
2353 * Check whether the REF_HAVE_OLD and old_oid values stored in update
2354 * are consistent with oid, which is the reference's current value. If
2355 * everything is OK, return 0; otherwise, write an error message to
2356 * err and return -1.
2357 */
2358 static int check_old_oid(struct ref_update *update, struct object_id *oid,
2359 struct strbuf *err)
2360 {
2361 if (!(update->flags & REF_HAVE_OLD) ||
2362 oideq(oid, &update->old_oid))
2363 return 0;
2364
2365 if (is_null_oid(&update->old_oid))
2366 strbuf_addf(err, "cannot lock ref '%s': "
2367 "reference already exists",
2368 original_update_refname(update));
2369 else if (is_null_oid(oid))
2370 strbuf_addf(err, "cannot lock ref '%s': "
2371 "reference is missing but expected %s",
2372 original_update_refname(update),
2373 oid_to_hex(&update->old_oid));
2374 else
2375 strbuf_addf(err, "cannot lock ref '%s': "
2376 "is at %s but expected %s",
2377 original_update_refname(update),
2378 oid_to_hex(oid),
2379 oid_to_hex(&update->old_oid));
2380
2381 return -1;
2382 }
2383
2384 /*
2385 * Prepare for carrying out update:
2386 * - Lock the reference referred to by update.
2387 * - Read the reference under lock.
2388 * - Check that its old OID value (if specified) is correct, and in
2389 * any case record it in update->lock->old_oid for later use when
2390 * writing the reflog.
2391 * - If it is a symref update without REF_NO_DEREF, split it up into a
2392 * REF_LOG_ONLY update of the symref and add a separate update for
2393 * the referent to transaction.
2394 * - If it is an update of head_ref, add a corresponding REF_LOG_ONLY
2395 * update of HEAD.
2396 */
2397 static int lock_ref_for_update(struct files_ref_store *refs,
2398 struct ref_update *update,
2399 struct ref_transaction *transaction,
2400 const char *head_ref,
2401 struct string_list *affected_refnames,
2402 struct strbuf *err)
2403 {
2404 struct strbuf referent = STRBUF_INIT;
2405 int mustexist = (update->flags & REF_HAVE_OLD) &&
2406 !is_null_oid(&update->old_oid);
2407 int ret = 0;
2408 struct ref_lock *lock;
2409
2410 files_assert_main_repository(refs, "lock_ref_for_update");
2411
2412 if ((update->flags & REF_HAVE_NEW) && is_null_oid(&update->new_oid))
2413 update->flags |= REF_DELETING;
2414
2415 if (head_ref) {
2416 ret = split_head_update(update, transaction, head_ref,
2417 affected_refnames, err);
2418 if (ret)
2419 goto out;
2420 }
2421
2422 ret = lock_raw_ref(refs, update->refname, mustexist,
2423 affected_refnames, NULL,
2424 &lock, &referent,
2425 &update->type, err);
2426 if (ret) {
2427 char *reason;
2428
2429 reason = strbuf_detach(err, NULL);
2430 strbuf_addf(err, "cannot lock ref '%s': %s",
2431 original_update_refname(update), reason);
2432 free(reason);
2433 goto out;
2434 }
2435
2436 update->backend_data = lock;
2437
2438 if (update->type & REF_ISSYMREF) {
2439 if (update->flags & REF_NO_DEREF) {
2440 /*
2441 * We won't be reading the referent as part of
2442 * the transaction, so we have to read it here
2443 * to record and possibly check old_oid:
2444 */
2445 if (refs_read_ref_full(&refs->base,
2446 referent.buf, 0,
2447 &lock->old_oid, NULL)) {
2448 if (update->flags & REF_HAVE_OLD) {
2449 strbuf_addf(err, "cannot lock ref '%s': "
2450 "error reading reference",
2451 original_update_refname(update));
2452 ret = TRANSACTION_GENERIC_ERROR;
2453 goto out;
2454 }
2455 } else if (check_old_oid(update, &lock->old_oid, err)) {
2456 ret = TRANSACTION_GENERIC_ERROR;
2457 goto out;
2458 }
2459 } else {
2460 /*
2461 * Create a new update for the reference this
2462 * symref is pointing at. Also, we will record
2463 * and verify old_oid for this update as part
2464 * of processing the split-off update, so we
2465 * don't have to do it here.
2466 */
2467 ret = split_symref_update(update,
2468 referent.buf, transaction,
2469 affected_refnames, err);
2470 if (ret)
2471 goto out;
2472 }
2473 } else {
2474 struct ref_update *parent_update;
2475
2476 if (check_old_oid(update, &lock->old_oid, err)) {
2477 ret = TRANSACTION_GENERIC_ERROR;
2478 goto out;
2479 }
2480
2481 /*
2482 * If this update is happening indirectly because of a
2483 * symref update, record the old OID in the parent
2484 * update:
2485 */
2486 for (parent_update = update->parent_update;
2487 parent_update;
2488 parent_update = parent_update->parent_update) {
2489 struct ref_lock *parent_lock = parent_update->backend_data;
2490 oidcpy(&parent_lock->old_oid, &lock->old_oid);
2491 }
2492 }
2493
2494 if ((update->flags & REF_HAVE_NEW) &&
2495 !(update->flags & REF_DELETING) &&
2496 !(update->flags & REF_LOG_ONLY)) {
2497 if (!(update->type & REF_ISSYMREF) &&
2498 oideq(&lock->old_oid, &update->new_oid)) {
2499 /*
2500 * The reference already has the desired
2501 * value, so we don't need to write it.
2502 */
2503 } else if (write_ref_to_lockfile(lock, &update->new_oid,
2504 err)) {
2505 char *write_err = strbuf_detach(err, NULL);
2506
2507 /*
2508 * The lock was freed upon failure of
2509 * write_ref_to_lockfile():
2510 */
2511 update->backend_data = NULL;
2512 strbuf_addf(err,
2513 "cannot update ref '%s': %s",
2514 update->refname, write_err);
2515 free(write_err);
2516 ret = TRANSACTION_GENERIC_ERROR;
2517 goto out;
2518 } else {
2519 update->flags |= REF_NEEDS_COMMIT;
2520 }
2521 }
2522 if (!(update->flags & REF_NEEDS_COMMIT)) {
2523 /*
2524 * We didn't call write_ref_to_lockfile(), so
2525 * the lockfile is still open. Close it to
2526 * free up the file descriptor:
2527 */
2528 if (close_ref_gently(lock)) {
2529 strbuf_addf(err, "couldn't close '%s.lock'",
2530 update->refname);
2531 ret = TRANSACTION_GENERIC_ERROR;
2532 goto out;
2533 }
2534 }
2535
2536 out:
2537 strbuf_release(&referent);
2538 return ret;
2539 }
2540
2541 struct files_transaction_backend_data {
2542 struct ref_transaction *packed_transaction;
2543 int packed_refs_locked;
2544 };
2545
2546 /*
2547 * Unlock any references in `transaction` that are still locked, and
2548 * mark the transaction closed.
2549 */
2550 static void files_transaction_cleanup(struct files_ref_store *refs,
2551 struct ref_transaction *transaction)
2552 {
2553 size_t i;
2554 struct files_transaction_backend_data *backend_data =
2555 transaction->backend_data;
2556 struct strbuf err = STRBUF_INIT;
2557
2558 for (i = 0; i < transaction->nr; i++) {
2559 struct ref_update *update = transaction->updates[i];
2560 struct ref_lock *lock = update->backend_data;
2561
2562 if (lock) {
2563 unlock_ref(lock);
2564 update->backend_data = NULL;
2565 }
2566 }
2567
2568 if (backend_data->packed_transaction &&
2569 ref_transaction_abort(backend_data->packed_transaction, &err)) {
2570 error("error aborting transaction: %s", err.buf);
2571 strbuf_release(&err);
2572 }
2573
2574 if (backend_data->packed_refs_locked)
2575 packed_refs_unlock(refs->packed_ref_store);
2576
2577 free(backend_data);
2578
2579 transaction->state = REF_TRANSACTION_CLOSED;
2580 }
2581
2582 static int files_transaction_prepare(struct ref_store *ref_store,
2583 struct ref_transaction *transaction,
2584 struct strbuf *err)
2585 {
2586 struct files_ref_store *refs =
2587 files_downcast(ref_store, REF_STORE_WRITE,
2588 "ref_transaction_prepare");
2589 size_t i;
2590 int ret = 0;
2591 struct string_list affected_refnames = STRING_LIST_INIT_NODUP;
2592 char *head_ref = NULL;
2593 int head_type;
2594 struct files_transaction_backend_data *backend_data;
2595 struct ref_transaction *packed_transaction = NULL;
2596
2597 assert(err);
2598
2599 if (!transaction->nr)
2600 goto cleanup;
2601
2602 backend_data = xcalloc(1, sizeof(*backend_data));
2603 transaction->backend_data = backend_data;
2604
2605 /*
2606 * Fail if a refname appears more than once in the
2607 * transaction. (If we end up splitting up any updates using
2608 * split_symref_update() or split_head_update(), those
2609 * functions will check that the new updates don't have the
2610 * same refname as any existing ones.) Also fail if any of the
2611 * updates use REF_IS_PRUNING without REF_NO_DEREF.
2612 */
2613 for (i = 0; i < transaction->nr; i++) {
2614 struct ref_update *update = transaction->updates[i];
2615 struct string_list_item *item =
2616 string_list_append(&affected_refnames, update->refname);
2617
2618 if ((update->flags & REF_IS_PRUNING) &&
2619 !(update->flags & REF_NO_DEREF))
2620 BUG("REF_IS_PRUNING set without REF_NO_DEREF");
2621
2622 /*
2623 * We store a pointer to update in item->util, but at
2624 * the moment we never use the value of this field
2625 * except to check whether it is non-NULL.
2626 */
2627 item->util = update;
2628 }
2629 string_list_sort(&affected_refnames);
2630 if (ref_update_reject_duplicates(&affected_refnames, err)) {
2631 ret = TRANSACTION_GENERIC_ERROR;
2632 goto cleanup;
2633 }
2634
2635 /*
2636 * Special hack: If a branch is updated directly and HEAD
2637 * points to it (may happen on the remote side of a push
2638 * for example) then logically the HEAD reflog should be
2639 * updated too.
2640 *
2641 * A generic solution would require reverse symref lookups,
2642 * but finding all symrefs pointing to a given branch would be
2643 * rather costly for this rare event (the direct update of a
2644 * branch) to be worth it. So let's cheat and check with HEAD
2645 * only, which should cover 99% of all usage scenarios (even
2646 * 100% of the default ones).
2647 *
2648 * So if HEAD is a symbolic reference, then record the name of
2649 * the reference that it points to. If we see an update of
2650 * head_ref within the transaction, then split_head_update()
2651 * arranges for the reflog of HEAD to be updated, too.
2652 */
2653 head_ref = refs_resolve_refdup(ref_store, "HEAD",
2654 RESOLVE_REF_NO_RECURSE,
2655 NULL, &head_type);
2656
2657 if (head_ref && !(head_type & REF_ISSYMREF)) {
2658 FREE_AND_NULL(head_ref);
2659 }
2660
2661 /*
2662 * Acquire all locks, verify old values if provided, check
2663 * that new values are valid, and write new values to the
2664 * lockfiles, ready to be activated. Only keep one lockfile
2665 * open at a time to avoid running out of file descriptors.
2666 * Note that lock_ref_for_update() might append more updates
2667 * to the transaction.
2668 */
2669 for (i = 0; i < transaction->nr; i++) {
2670 struct ref_update *update = transaction->updates[i];
2671
2672 ret = lock_ref_for_update(refs, update, transaction,
2673 head_ref, &affected_refnames, err);
2674 if (ret)
2675 goto cleanup;
2676
2677 if (update->flags & REF_DELETING &&
2678 !(update->flags & REF_LOG_ONLY) &&
2679 !(update->flags & REF_IS_PRUNING)) {
2680 /*
2681 * This reference has to be deleted from
2682 * packed-refs if it exists there.
2683 */
2684 if (!packed_transaction) {
2685 packed_transaction = ref_store_transaction_begin(
2686 refs->packed_ref_store, err);
2687 if (!packed_transaction) {
2688 ret = TRANSACTION_GENERIC_ERROR;
2689 goto cleanup;
2690 }
2691
2692 backend_data->packed_transaction =
2693 packed_transaction;
2694 }
2695
2696 ref_transaction_add_update(
2697 packed_transaction, update->refname,
2698 REF_HAVE_NEW | REF_NO_DEREF,
2699 &update->new_oid, NULL,
2700 NULL);
2701 }
2702 }
2703
2704 if (packed_transaction) {
2705 if (packed_refs_lock(refs->packed_ref_store, 0, err)) {
2706 ret = TRANSACTION_GENERIC_ERROR;
2707 goto cleanup;
2708 }
2709 backend_data->packed_refs_locked = 1;
2710
2711 if (is_packed_transaction_needed(refs->packed_ref_store,
2712 packed_transaction)) {
2713 ret = ref_transaction_prepare(packed_transaction, err);
2714 /*
2715 * A failure during the prepare step will abort
2716 * itself, but not free. Do that now, and disconnect
2717 * from the files_transaction so it does not try to
2718 * abort us when we hit the cleanup code below.
2719 */
2720 if (ret) {
2721 ref_transaction_free(packed_transaction);
2722 backend_data->packed_transaction = NULL;
2723 }
2724 } else {
2725 /*
2726 * We can skip rewriting the `packed-refs`
2727 * file. But we do need to leave it locked, so
2728 * that somebody else doesn't pack a reference
2729 * that we are trying to delete.
2730 *
2731 * We need to disconnect our transaction from
2732 * backend_data, since the abort (whether successful or
2733 * not) will free it.
2734 */
2735 backend_data->packed_transaction = NULL;
2736 if (ref_transaction_abort(packed_transaction, err)) {
2737 ret = TRANSACTION_GENERIC_ERROR;
2738 goto cleanup;
2739 }
2740 }
2741 }
2742
2743 cleanup:
2744 free(head_ref);
2745 string_list_clear(&affected_refnames, 0);
2746
2747 if (ret)
2748 files_transaction_cleanup(refs, transaction);
2749 else
2750 transaction->state = REF_TRANSACTION_PREPARED;
2751
2752 return ret;
2753 }
2754
2755 static int files_transaction_finish(struct ref_store *ref_store,
2756 struct ref_transaction *transaction,
2757 struct strbuf *err)
2758 {
2759 struct files_ref_store *refs =
2760 files_downcast(ref_store, 0, "ref_transaction_finish");
2761 size_t i;
2762 int ret = 0;
2763 struct strbuf sb = STRBUF_INIT;
2764 struct files_transaction_backend_data *backend_data;
2765 struct ref_transaction *packed_transaction;
2766
2767
2768 assert(err);
2769
2770 if (!transaction->nr) {
2771 transaction->state = REF_TRANSACTION_CLOSED;
2772 return 0;
2773 }
2774
2775 backend_data = transaction->backend_data;
2776 packed_transaction = backend_data->packed_transaction;
2777
2778 /* Perform updates first so live commits remain referenced */
2779 for (i = 0; i < transaction->nr; i++) {
2780 struct ref_update *update = transaction->updates[i];
2781 struct ref_lock *lock = update->backend_data;
2782
2783 if (update->flags & REF_NEEDS_COMMIT ||
2784 update->flags & REF_LOG_ONLY) {
2785 if (files_log_ref_write(refs,
2786 lock->ref_name,
2787 &lock->old_oid,
2788 &update->new_oid,
2789 update->msg, update->flags,
2790 err)) {
2791 char *old_msg = strbuf_detach(err, NULL);
2792
2793 strbuf_addf(err, "cannot update the ref '%s': %s",
2794 lock->ref_name, old_msg);
2795 free(old_msg);
2796 unlock_ref(lock);
2797 update->backend_data = NULL;
2798 ret = TRANSACTION_GENERIC_ERROR;
2799 goto cleanup;
2800 }
2801 }
2802 if (update->flags & REF_NEEDS_COMMIT) {
2803 clear_loose_ref_cache(refs);
2804 if (commit_ref(lock)) {
2805 strbuf_addf(err, "couldn't set '%s'", lock->ref_name);
2806 unlock_ref(lock);
2807 update->backend_data = NULL;
2808 ret = TRANSACTION_GENERIC_ERROR;
2809 goto cleanup;
2810 }
2811 }
2812 }
2813
2814 /*
2815 * Now that updates are safely completed, we can perform
2816 * deletes. First delete the reflogs of any references that
2817 * will be deleted, since (in the unexpected event of an
2818 * error) leaving a reference without a reflog is less bad
2819 * than leaving a reflog without a reference (the latter is a
2820 * mildly invalid repository state):
2821 */
2822 for (i = 0; i < transaction->nr; i++) {
2823 struct ref_update *update = transaction->updates[i];
2824 if (update->flags & REF_DELETING &&
2825 !(update->flags & REF_LOG_ONLY) &&
2826 !(update->flags & REF_IS_PRUNING)) {
2827 strbuf_reset(&sb);
2828 files_reflog_path(refs, &sb, update->refname);
2829 if (!unlink_or_warn(sb.buf))
2830 try_remove_empty_parents(refs, update->refname,
2831 REMOVE_EMPTY_PARENTS_REFLOG);
2832 }
2833 }
2834
2835 /*
2836 * Perform deletes now that updates are safely completed.
2837 *
2838 * First delete any packed versions of the references, while
2839 * retaining the packed-refs lock:
2840 */
2841 if (packed_transaction) {
2842 ret = ref_transaction_commit(packed_transaction, err);
2843 ref_transaction_free(packed_transaction);
2844 packed_transaction = NULL;
2845 backend_data->packed_transaction = NULL;
2846 if (ret)
2847 goto cleanup;
2848 }
2849
2850 /* Now delete the loose versions of the references: */
2851 for (i = 0; i < transaction->nr; i++) {
2852 struct ref_update *update = transaction->updates[i];
2853 struct ref_lock *lock = update->backend_data;
2854
2855 if (update->flags & REF_DELETING &&
2856 !(update->flags & REF_LOG_ONLY)) {
2857 if (!(update->type & REF_ISPACKED) ||
2858 update->type & REF_ISSYMREF) {
2859 /* It is a loose reference. */
2860 strbuf_reset(&sb);
2861 files_ref_path(refs, &sb, lock->ref_name);
2862 if (unlink_or_msg(sb.buf, err)) {
2863 ret = TRANSACTION_GENERIC_ERROR;
2864 goto cleanup;
2865 }
2866 update->flags |= REF_DELETED_LOOSE;
2867 }
2868 }
2869 }
2870
2871 clear_loose_ref_cache(refs);
2872
2873 cleanup:
2874 files_transaction_cleanup(refs, transaction);
2875
2876 for (i = 0; i < transaction->nr; i++) {
2877 struct ref_update *update = transaction->updates[i];
2878
2879 if (update->flags & REF_DELETED_LOOSE) {
2880 /*
2881 * The loose reference was deleted. Delete any
2882 * empty parent directories. (Note that this
2883 * can only work because we have already
2884 * removed the lockfile.)
2885 */
2886 try_remove_empty_parents(refs, update->refname,
2887 REMOVE_EMPTY_PARENTS_REF);
2888 }
2889 }
2890
2891 strbuf_release(&sb);
2892 return ret;
2893 }
2894
2895 static int files_transaction_abort(struct ref_store *ref_store,
2896 struct ref_transaction *transaction,
2897 struct strbuf *err)
2898 {
2899 struct files_ref_store *refs =
2900 files_downcast(ref_store, 0, "ref_transaction_abort");
2901
2902 files_transaction_cleanup(refs, transaction);
2903 return 0;
2904 }
2905
2906 static int ref_present(const char *refname,
2907 const struct object_id *oid, int flags, void *cb_data)
2908 {
2909 struct string_list *affected_refnames = cb_data;
2910
2911 return string_list_has_string(affected_refnames, refname);
2912 }
2913
2914 static int files_initial_transaction_commit(struct ref_store *ref_store,
2915 struct ref_transaction *transaction,
2916 struct strbuf *err)
2917 {
2918 struct files_ref_store *refs =
2919 files_downcast(ref_store, REF_STORE_WRITE,
2920 "initial_ref_transaction_commit");
2921 size_t i;
2922 int ret = 0;
2923 struct string_list affected_refnames = STRING_LIST_INIT_NODUP;
2924 struct ref_transaction *packed_transaction = NULL;
2925
2926 assert(err);
2927
2928 if (transaction->state != REF_TRANSACTION_OPEN)
2929 BUG("commit called for transaction that is not open");
2930
2931 /* Fail if a refname appears more than once in the transaction: */
2932 for (i = 0; i < transaction->nr; i++)
2933 string_list_append(&affected_refnames,
2934 transaction->updates[i]->refname);
2935 string_list_sort(&affected_refnames);
2936 if (ref_update_reject_duplicates(&affected_refnames, err)) {
2937 ret = TRANSACTION_GENERIC_ERROR;
2938 goto cleanup;
2939 }
2940
2941 /*
2942 * It's really undefined to call this function in an active
2943 * repository or when there are existing references: we are
2944 * only locking and changing packed-refs, so (1) any
2945 * simultaneous processes might try to change a reference at
2946 * the same time we do, and (2) any existing loose versions of
2947 * the references that we are setting would have precedence
2948 * over our values. But some remote helpers create the remote
2949 * "HEAD" and "master" branches before calling this function,
2950 * so here we really only check that none of the references
2951 * that we are creating already exists.
2952 */
2953 if (refs_for_each_rawref(&refs->base, ref_present,
2954 &affected_refnames))
2955 BUG("initial ref transaction called with existing refs");
2956
2957 packed_transaction = ref_store_transaction_begin(refs->packed_ref_store, err);
2958 if (!packed_transaction) {
2959 ret = TRANSACTION_GENERIC_ERROR;
2960 goto cleanup;
2961 }
2962
2963 for (i = 0; i < transaction->nr; i++) {
2964 struct ref_update *update = transaction->updates[i];
2965
2966 if ((update->flags & REF_HAVE_OLD) &&
2967 !is_null_oid(&update->old_oid))
2968 BUG("initial ref transaction with old_sha1 set");
2969 if (refs_verify_refname_available(&refs->base, update->refname,
2970 &affected_refnames, NULL,
2971 err)) {
2972 ret = TRANSACTION_NAME_CONFLICT;
2973 goto cleanup;
2974 }
2975
2976 /*
2977 * Add a reference creation for this reference to the
2978 * packed-refs transaction:
2979 */
2980 ref_transaction_add_update(packed_transaction, update->refname,
2981 update->flags & ~REF_HAVE_OLD,
2982 &update->new_oid, &update->old_oid,
2983 NULL);
2984 }
2985
2986 if (packed_refs_lock(refs->packed_ref_store, 0, err)) {
2987 ret = TRANSACTION_GENERIC_ERROR;
2988 goto cleanup;
2989 }
2990
2991 if (initial_ref_transaction_commit(packed_transaction, err)) {
2992 ret = TRANSACTION_GENERIC_ERROR;
2993 }
2994
2995 packed_refs_unlock(refs->packed_ref_store);
2996 cleanup:
2997 if (packed_transaction)
2998 ref_transaction_free(packed_transaction);
2999 transaction->state = REF_TRANSACTION_CLOSED;
3000 string_list_clear(&affected_refnames, 0);
3001 return ret;
3002 }
3003
3004 struct expire_reflog_cb {
3005 unsigned int flags;
3006 reflog_expiry_should_prune_fn *should_prune_fn;
3007 void *policy_cb;
3008 FILE *newlog;
3009 struct object_id last_kept_oid;
3010 };
3011
3012 static int expire_reflog_ent(struct object_id *ooid, struct object_id *noid,
3013 const char *email, timestamp_t timestamp, int tz,
3014 const char *message, void *cb_data)
3015 {
3016 struct expire_reflog_cb *cb = cb_data;
3017 struct expire_reflog_policy_cb *policy_cb = cb->policy_cb;
3018
3019 if (cb->flags & EXPIRE_REFLOGS_REWRITE)
3020 ooid = &cb->last_kept_oid;
3021
3022 if ((*cb->should_prune_fn)(ooid, noid, email, timestamp, tz,
3023 message, policy_cb)) {
3024 if (!cb->newlog)
3025 printf("would prune %s", message);
3026 else if (cb->flags & EXPIRE_REFLOGS_VERBOSE)
3027 printf("prune %s", message);
3028 } else {
3029 if (cb->newlog) {
3030 fprintf(cb->newlog, "%s %s %s %"PRItime" %+05d\t%s",
3031 oid_to_hex(ooid), oid_to_hex(noid),
3032 email, timestamp, tz, message);
3033 oidcpy(&cb->last_kept_oid, noid);
3034 }
3035 if (cb->flags & EXPIRE_REFLOGS_VERBOSE)
3036 printf("keep %s", message);
3037 }
3038 return 0;
3039 }
3040
3041 static int files_reflog_expire(struct ref_store *ref_store,
3042 const char *refname, const struct object_id *oid,
3043 unsigned int flags,
3044 reflog_expiry_prepare_fn prepare_fn,
3045 reflog_expiry_should_prune_fn should_prune_fn,
3046 reflog_expiry_cleanup_fn cleanup_fn,
3047 void *policy_cb_data)
3048 {
3049 struct files_ref_store *refs =
3050 files_downcast(ref_store, REF_STORE_WRITE, "reflog_expire");
3051 struct lock_file reflog_lock = LOCK_INIT;
3052 struct expire_reflog_cb cb;
3053 struct ref_lock *lock;
3054 struct strbuf log_file_sb = STRBUF_INIT;
3055 char *log_file;
3056 int status = 0;
3057 int type;
3058 struct strbuf err = STRBUF_INIT;
3059
3060 memset(&cb, 0, sizeof(cb));
3061 cb.flags = flags;
3062 cb.policy_cb = policy_cb_data;
3063 cb.should_prune_fn = should_prune_fn;
3064
3065 /*
3066 * The reflog file is locked by holding the lock on the
3067 * reference itself, plus we might need to update the
3068 * reference if --updateref was specified:
3069 */
3070 lock = lock_ref_oid_basic(refs, refname, oid,
3071 NULL, NULL, REF_NO_DEREF,
3072 &type, &err);
3073 if (!lock) {
3074 error("cannot lock ref '%s': %s", refname, err.buf);
3075 strbuf_release(&err);
3076 return -1;
3077 }
3078 if (!refs_reflog_exists(ref_store, refname)) {
3079 unlock_ref(lock);
3080 return 0;
3081 }
3082
3083 files_reflog_path(refs, &log_file_sb, refname);
3084 log_file = strbuf_detach(&log_file_sb, NULL);
3085 if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {
3086 /*
3087 * Even though holding $GIT_DIR/logs/$reflog.lock has
3088 * no locking implications, we use the lock_file
3089 * machinery here anyway because it does a lot of the
3090 * work we need, including cleaning up if the program
3091 * exits unexpectedly.
3092 */
3093 if (hold_lock_file_for_update(&reflog_lock, log_file, 0) < 0) {
3094 struct strbuf err = STRBUF_INIT;
3095 unable_to_lock_message(log_file, errno, &err);
3096 error("%s", err.buf);
3097 strbuf_release(&err);
3098 goto failure;
3099 }
3100 cb.newlog = fdopen_lock_file(&reflog_lock, "w");
3101 if (!cb.newlog) {
3102 error("cannot fdopen %s (%s)",
3103 get_lock_file_path(&reflog_lock), strerror(errno));
3104 goto failure;
3105 }
3106 }
3107
3108 (*prepare_fn)(refname, oid, cb.policy_cb);
3109 refs_for_each_reflog_ent(ref_store, refname, expire_reflog_ent, &cb);
3110 (*cleanup_fn)(cb.policy_cb);
3111
3112 if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {
3113 /*
3114 * It doesn't make sense to adjust a reference pointed
3115 * to by a symbolic ref based on expiring entries in
3116 * the symbolic reference's reflog. Nor can we update
3117 * a reference if there are no remaining reflog
3118 * entries.
3119 */
3120 int update = (flags & EXPIRE_REFLOGS_UPDATE_REF) &&
3121 !(type & REF_ISSYMREF) &&
3122 !is_null_oid(&cb.last_kept_oid);
3123
3124 if (close_lock_file_gently(&reflog_lock)) {
3125 status |= error("couldn't write %s: %s", log_file,
3126 strerror(errno));
3127 rollback_lock_file(&reflog_lock);
3128 } else if (update &&
3129 (write_in_full(get_lock_file_fd(&lock->lk),
3130 oid_to_hex(&cb.last_kept_oid), the_hash_algo->hexsz) < 0 ||
3131 write_str_in_full(get_lock_file_fd(&lock->lk), "\n") < 0 ||
3132 close_ref_gently(lock) < 0)) {
3133 status |= error("couldn't write %s",
3134 get_lock_file_path(&lock->lk));
3135 rollback_lock_file(&reflog_lock);
3136 } else if (commit_lock_file(&reflog_lock)) {
3137 status |= error("unable to write reflog '%s' (%s)",
3138 log_file, strerror(errno));
3139 } else if (update && commit_ref(lock)) {
3140 status |= error("couldn't set %s", lock->ref_name);
3141 }
3142 }
3143 free(log_file);
3144 unlock_ref(lock);
3145 return status;
3146
3147 failure:
3148 rollback_lock_file(&reflog_lock);
3149 free(log_file);
3150 unlock_ref(lock);
3151 return -1;
3152 }
3153
3154 static int files_init_db(struct ref_store *ref_store, struct strbuf *err)
3155 {
3156 struct files_ref_store *refs =
3157 files_downcast(ref_store, REF_STORE_WRITE, "init_db");
3158 struct strbuf sb = STRBUF_INIT;
3159
3160 /*
3161 * Create .git/refs/{heads,tags}
3162 */
3163 files_ref_path(refs, &sb, "refs/heads");
3164 safe_create_dir(sb.buf, 1);
3165
3166 strbuf_reset(&sb);
3167 files_ref_path(refs, &sb, "refs/tags");
3168 safe_create_dir(sb.buf, 1);
3169
3170 strbuf_release(&sb);
3171 return 0;
3172 }
3173
3174 struct ref_storage_be refs_be_files = {
3175 NULL,
3176 "files",
3177 files_ref_store_create,
3178 files_init_db,
3179 files_transaction_prepare,
3180 files_transaction_finish,
3181 files_transaction_abort,
3182 files_initial_transaction_commit,
3183
3184 files_pack_refs,
3185 files_create_symref,
3186 files_delete_refs,
3187 files_rename_ref,
3188 files_copy_ref,
3189
3190 files_ref_iterator_begin,
3191 files_read_raw_ref,
3192
3193 files_reflog_iterator_begin,
3194 files_for_each_reflog_ent,
3195 files_for_each_reflog_ent_reverse,
3196 files_reflog_exists,
3197 files_create_reflog,
3198 files_delete_reflog,
3199 files_reflog_expire
3200 };