1 /*
2  * Copyright (c) 2018, 2019 Stefan Sperling <stsp@openbsd.org>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 #include "got_compat.h"
18 
19 #include <sys/types.h>
20 #include <sys/queue.h>
21 #include <sys/stat.h>
22 
23 #include <errno.h>
24 #include <dirent.h>
25 #include <limits.h>
26 #include <stdio.h>
27 #include <stdlib.h>
28 #include <string.h>
29 #include <unistd.h>
30 #include <zlib.h>
31 #include <time.h>
32 #include <libgen.h>
33 
34 #include "got_error.h"
35 #include "got_object.h"
36 #include "got_repository.h"
37 #include "got_reference.h"
38 #include "got_opentemp.h"
39 #include "got_path.h"
40 
41 #include "got_lib_hash.h"
42 #include "got_lib_delta.h"
43 #include "got_lib_inflate.h"
44 #include "got_lib_object.h"
45 #include "got_lib_object_idset.h"
46 #include "got_lib_lockfile.h"
47 
48 #ifndef nitems
49 #define nitems(_a) (sizeof(_a) / sizeof((_a)[0]))
50 #endif
51 
52 #define GOT_REF_HEADS	"heads"
53 #define GOT_REF_TAGS	"tags"
54 #define GOT_REF_REMOTES	"remotes"
55 
56 /*
57  * We do not resolve tags yet, and don't yet care about sorting refs either,
58  * so packed-refs files we write contain a minimal header which disables all
59  * packed-refs "traits" supported by Git.
60  */
61 #define GOT_PACKED_REFS_HEADER	"# pack-refs with:"
62 
63 /* A symbolic reference. */
64 struct got_symref {
65 	char *name;
66 	char *ref;
67 };
68 
69 #define GOT_REF_RECURSE_MAX	20
70 
71 /* A non-symbolic reference (there is no better designation). */
72 struct got_ref {
73 	char *name;
74 	struct got_object_id id;
75 };
76 
77 /* A reference which points to an arbitrary object. */
78 struct got_reference {
79 	unsigned int flags;
80 #define GOT_REF_IS_SYMBOLIC	0x01
81 #define GOT_REF_IS_PACKED	0x02
82 
83 	union {
84 		struct got_ref ref;
85 		struct got_symref symref;
86 	} ref;
87 
88 	struct got_lockfile *lf;
89 	time_t mtime;
90 
91 	/*
92 	 * Cached timestamp for got_ref_cmp_by_commit_timestamp_descending()
93 	 * and got_ref_cmp_tags().
94 	 */
95 	time_t committer_time;
96 };
97 
98 static const struct got_error *
99 alloc_ref(struct got_reference **ref, const char *name,
100     struct got_object_id *id, int flags, time_t mtime)
101 {
102 	const struct got_error *err = NULL;
103 
104 	*ref = calloc(1, sizeof(**ref));
105 	if (*ref == NULL)
106 		return got_error_from_errno("calloc");
107 
108 	memcpy(&(*ref)->ref.ref.id, id, sizeof((*ref)->ref.ref.id));
109 	(*ref)->flags = flags;
110 	(*ref)->ref.ref.name = strdup(name);
111 	(*ref)->mtime = mtime;
112 	if ((*ref)->ref.ref.name == NULL) {
113 		err = got_error_from_errno("strdup");
114 		got_ref_close(*ref);
115 		*ref = NULL;
116 	}
117 	return err;
118 }
119 
120 static const struct got_error *
121 alloc_symref(struct got_reference **ref, const char *name,
122     const char *target_ref, int flags)
123 {
124 	const struct got_error *err = NULL;
125 
126 	*ref = calloc(1, sizeof(**ref));
127 	if (*ref == NULL)
128 		return got_error_from_errno("calloc");
129 
130 	(*ref)->flags = GOT_REF_IS_SYMBOLIC | flags;
131 	(*ref)->ref.symref.name = strdup(name);
132 	if ((*ref)->ref.symref.name == NULL) {
133 		err = got_error_from_errno("strdup");
134 		got_ref_close(*ref);
135 		*ref = NULL;
136 		return err;
137 	}
138 	(*ref)->ref.symref.ref = strdup(target_ref);
139 	if ((*ref)->ref.symref.ref == NULL) {
140 		err = got_error_from_errno("strdup");
141 		got_ref_close(*ref);
142 		*ref = NULL;
143 	}
144 	return err;
145 }
146 
147 static const struct got_error *
148 parse_symref(struct got_reference **ref, const char *name, const char *line)
149 {
150 	if (line[0] == '\0')
151 		return got_error(GOT_ERR_BAD_REF_DATA);
152 
153 	return alloc_symref(ref, name, line, 0);
154 }
155 
156 static const struct got_error *
157 parse_ref_line(struct got_reference **ref, const char *name, const char *line,
158     time_t mtime, enum got_hash_algorithm algo)
159 {
160 	struct got_object_id id;
161 
162 	if (strncmp(line, "ref: ", 5) == 0) {
163 		line += 5;
164 		return parse_symref(ref, name, line);
165 	}
166 
167 	if (!got_parse_object_id(&id, line, algo))
168 		return got_error(GOT_ERR_BAD_REF_DATA);
169 
170 	return alloc_ref(ref, name, &id, 0, mtime);
171 }
172 
173 static const struct got_error *
174 parse_ref_file(struct got_reference **ref, const char *name,
175     const char *absname, const char *abspath, int lock,
176     enum got_hash_algorithm algo)
177 {
178 	const struct got_error *err = NULL;
179 	FILE *f;
180 	char *line = NULL;
181 	size_t linesize = 0;
182 	ssize_t linelen;
183 	struct got_lockfile *lf = NULL;
184 	struct stat sb;
185 
186 	if (lock) {
187 		err = got_lockfile_lock(&lf, abspath, -1);
188 		if (err) {
189 			if (err->code == GOT_ERR_ERRNO && errno == ENOENT)
190 				err = got_error_not_ref(name);
191 			return err;
192 		}
193 	}
194 
195 	f = fopen(abspath, "rbe");
196 	if (f == NULL) {
197 		if (errno != ENOTDIR && errno != ENOENT)
198 			err = got_error_from_errno2("fopen", abspath);
199 		else
200 			err = got_error_not_ref(name);
201 		if (lock)
202 			got_lockfile_unlock(lf, -1);
203 		return err;
204 	}
205 	if (fstat(fileno(f), &sb) == -1) {
206 		err = got_error_from_errno2("fstat", abspath);
207 		goto done;
208 	}
209 
210 	linelen = getline(&line, &linesize, f);
211 	if (linelen == -1) {
212 		if (feof(f))
213 			err = NULL; /* ignore empty files (could be locks) */
214 		else {
215 			if (errno == EISDIR)
216 				err = got_error(GOT_ERR_NOT_REF);
217 			else if (ferror(f))
218 				err = got_ferror(f, GOT_ERR_IO);
219 			else
220 				err = got_error_from_errno2("getline", abspath);
221 		}
222 		if (lock)
223 			got_lockfile_unlock(lf, -1);
224 		goto done;
225 	}
226 	while (linelen > 0 && line[linelen - 1] == '\n') {
227 		line[linelen - 1] = '\0';
228 		linelen--;
229 	}
230 
231 	err = parse_ref_line(ref, absname, line, sb.st_mtime, algo);
232 	if (lock) {
233 		if (err)
234 			got_lockfile_unlock(lf, -1);
235 		else {
236 			if (*ref)
237 				(*ref)->lf = lf;
238 			else
239 				got_lockfile_unlock(lf, -1);
240 		}
241 	}
242 done:
243 	free(line);
244 	if (fclose(f) == EOF && err == NULL) {
245 		err = got_error_from_errno("fclose");
246 		if (*ref) {
247 			if (lock)
248 				got_ref_unlock(*ref);
249 			got_ref_close(*ref);
250 			*ref = NULL;
251 		}
252 	}
253 	return err;
254 }
255 
256 static int
257 is_well_known_ref(const char *refname)
258 {
259 	return (strcmp(refname, GOT_REF_HEAD) == 0 ||
260 	    strcmp(refname, GOT_REF_ORIG_HEAD) == 0 ||
261 	    strcmp(refname, GOT_REF_MERGE_HEAD) == 0 ||
262 	    strcmp(refname, GOT_REF_FETCH_HEAD) == 0);
263 }
264 
265 static char *
266 get_refs_dir_path(struct got_repository *repo, const char *refname)
267 {
268 	if (is_well_known_ref(refname) || strncmp(refname, "refs/", 5) == 0)
269 		return strdup(got_repo_get_path_git_dir(repo));
270 
271 	return got_repo_get_path_refs(repo);
272 }
273 
274 const struct got_error *
275 got_ref_alloc(struct got_reference **ref, const char *name,
276     struct got_object_id *id)
277 {
278 	if (!got_ref_name_is_valid(name))
279 		return got_error_path(name, GOT_ERR_BAD_REF_NAME);
280 
281 	return alloc_ref(ref, name, id, 0, 0);
282 }
283 
284 const struct got_error *
285 got_ref_alloc_symref(struct got_reference **ref, const char *name,
286 	struct got_reference *target_ref)
287 {
288 	if (!got_ref_name_is_valid(name))
289 		return got_error_path(name, GOT_ERR_BAD_REF_NAME);
290 
291 	return alloc_symref(ref, name, got_ref_get_name(target_ref), 0);
292 }
293 
294 static const struct got_error *
295 parse_packed_ref_line(struct got_reference **ref, const char *abs_refname,
296     const char *line, time_t mtime, enum got_hash_algorithm algo)
297 {
298 	struct got_object_id id;
299 	const char *name;
300 
301 	*ref = NULL;
302 
303 	if (line[0] == '#' || line[0] == '^')
304 		return NULL;
305 
306 	if (!got_parse_object_id(&id, line, algo))
307 		return got_error(GOT_ERR_BAD_REF_DATA);
308 
309 	if (abs_refname) {
310 		if (strcmp(line + SHA1_DIGEST_STRING_LENGTH, abs_refname) != 0)
311 			return NULL;
312 		name = abs_refname;
313 	} else
314 		name = line + SHA1_DIGEST_STRING_LENGTH;
315 
316 	return alloc_ref(ref, name, &id, GOT_REF_IS_PACKED, mtime);
317 }
318 
319 static const struct got_error *
320 open_packed_ref(struct got_reference **ref, FILE *f, const char **subdirs,
321     int nsubdirs, const char *refname, time_t mtime,
322     enum got_hash_algorithm algo)
323 {
324 	const struct got_error *err = NULL;
325 	char *abs_refname;
326 	char *line = NULL;
327 	size_t linesize = 0;
328 	ssize_t linelen;
329 	int i, ref_is_absolute = (strncmp(refname, "refs/", 5) == 0);
330 
331 	*ref = NULL;
332 
333 	if (ref_is_absolute)
334 		abs_refname = (char *)refname;
335 	do {
336 		linelen = getline(&line, &linesize, f);
337 		if (linelen == -1) {
338 			if (feof(f))
339 				break;
340 			err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
341 			break;
342 		}
343 		if (linelen > 0 && line[linelen - 1] == '\n')
344 			line[linelen - 1] = '\0';
345 		for (i = 0; i < nsubdirs; i++) {
346 			if (!ref_is_absolute &&
347 			    asprintf(&abs_refname, "refs/%s/%s", subdirs[i],
348 			    refname) == -1)
349 				return got_error_from_errno("asprintf");
350 			err = parse_packed_ref_line(ref, abs_refname, line,
351 			    mtime, algo);
352 			if (!ref_is_absolute)
353 				free(abs_refname);
354 			if (err || *ref != NULL)
355 				break;
356 		}
357 		if (err)
358 			break;
359 	} while (*ref == NULL);
360 	free(line);
361 
362 	return err;
363 }
364 
365 static const struct got_error *
366 open_ref(struct got_reference **ref, const char *path_refs, const char *subdir,
367     const char *name, int lock, enum got_hash_algorithm algo)
368 {
369 	const struct got_error *err = NULL;
370 	char *path = NULL;
371 	char *absname = NULL;
372 	int ref_is_absolute = (strncmp(name, "refs/", 5) == 0);
373 	int ref_is_well_known = (subdir[0] == '\0' && is_well_known_ref(name));
374 
375 	*ref = NULL;
376 
377 	if (!got_ref_name_is_valid(name))
378 		return got_error_path(name, GOT_ERR_BAD_REF_NAME);
379 
380 	if (ref_is_absolute || ref_is_well_known) {
381 		if (asprintf(&path, "%s/%s", path_refs, name) == -1)
382 			return got_error_from_errno("asprintf");
383 		absname = (char *)name;
384 	} else {
385 		if (asprintf(&path, "%s/%s%s%s", path_refs, subdir,
386 		    subdir[0] ? "/" : "", name) == -1)
387 			return got_error_from_errno("asprintf");
388 
389 		if (asprintf(&absname, "refs/%s%s%s",
390 		    subdir, subdir[0] ? "/" : "", name) == -1) {
391 			err = got_error_from_errno("asprintf");
392 			goto done;
393 		}
394 	}
395 
396 	err = parse_ref_file(ref, name, absname, path, lock, algo);
397 done:
398 	if (!ref_is_absolute && !ref_is_well_known)
399 		free(absname);
400 	free(path);
401 	return err;
402 }
403 
404 const struct got_error *
405 got_ref_open(struct got_reference **ref, struct got_repository *repo,
406     const char *refname, int lock)
407 {
408 	const struct got_error *err = NULL;
409 	char *packed_refs_path = NULL, *path_refs = NULL;
410 	const char *subdirs[] = {
411 	    GOT_REF_HEADS, GOT_REF_TAGS, GOT_REF_REMOTES
412 	};
413 	size_t i;
414 	int well_known = is_well_known_ref(refname);
415 	struct got_lockfile *lf = NULL;
416 
417 	*ref = NULL;
418 
419 	path_refs = get_refs_dir_path(repo, refname);
420 	if (path_refs == NULL) {
421 		err = got_error_from_errno2("get_refs_dir_path", refname);
422 		goto done;
423 	}
424 
425 	if (well_known) {
426 		err = open_ref(ref, path_refs, "", refname, lock,
427 		    got_repo_get_object_format(repo));
428 	} else {
429 		FILE *f;
430 
431 		/* Search on-disk refs before packed refs! */
432 		for (i = 0; i < nitems(subdirs); i++) {
433 			err = open_ref(ref, path_refs, subdirs[i], refname,
434 			    lock, got_repo_get_object_format(repo));
435 			if ((err && err->code != GOT_ERR_NOT_REF) || *ref)
436 				goto done;
437 		}
438 
439 		packed_refs_path = got_repo_get_path_packed_refs(repo);
440 		if (packed_refs_path == NULL) {
441 			err = got_error_from_errno(
442 			    "got_repo_get_path_packed_refs");
443 			goto done;
444 		}
445 
446 		if (lock) {
447 			err = got_lockfile_lock(&lf, packed_refs_path, -1);
448 			if (err)
449 				goto done;
450 		}
451 		f = fopen(packed_refs_path, "rbe");
452 		if (f != NULL) {
453 			struct stat sb;
454 			if (fstat(fileno(f), &sb) == -1) {
455 				err = got_error_from_errno2("fstat",
456 				    packed_refs_path);
457 				goto done;
458 			}
459 			err = open_packed_ref(ref, f, subdirs, nitems(subdirs),
460 			    refname, sb.st_mtime,
461 			    got_repo_get_object_format(repo));
462 			if (!err) {
463 				if (fclose(f) == EOF) {
464 					err = got_error_from_errno("fclose");
465 					got_ref_close(*ref);
466 					*ref = NULL;
467 				} else if (*ref)
468 					(*ref)->lf = lf;
469 			}
470 		}
471 	}
472 done:
473 	if (!err && *ref == NULL)
474 		err = got_error_not_ref(refname);
475 	if (err && lf)
476 		got_lockfile_unlock(lf, -1);
477 	free(packed_refs_path);
478 	free(path_refs);
479 	return err;
480 }
481 
482 void
483 got_ref_close(struct got_reference *ref)
484 {
485 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
486 		free(ref->ref.symref.name);
487 		free(ref->ref.symref.ref);
488 	} else
489 		free(ref->ref.ref.name);
490 	free(ref);
491 }
492 
493 struct got_reference *
494 got_ref_dup(struct got_reference *ref)
495 {
496 	struct got_reference *ret;
497 
498 	ret = calloc(1, sizeof(*ret));
499 	if (ret == NULL)
500 		return NULL;
501 
502 	ret->flags = ref->flags;
503 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
504 		ret->ref.symref.name = strdup(ref->ref.symref.name);
505 		if (ret->ref.symref.name == NULL) {
506 			free(ret);
507 			return NULL;
508 		}
509 		ret->ref.symref.ref = strdup(ref->ref.symref.ref);
510 		if (ret->ref.symref.ref == NULL) {
511 			free(ret->ref.symref.name);
512 			free(ret);
513 			return NULL;
514 		}
515 	} else {
516 		ret->ref.ref.name = strdup(ref->ref.ref.name);
517 		if (ret->ref.ref.name == NULL) {
518 			free(ret);
519 			return NULL;
520 		}
521 		memcpy(&ret->ref.ref.id, &ref->ref.ref.id,
522 		    sizeof(ret->ref.ref.id));
523 	}
524 
525 	return ret;
526 }
527 
528 const struct got_error *
529 got_reflist_entry_dup(struct got_reflist_entry **newp,
530     struct got_reflist_entry *re)
531 {
532 	const struct got_error *err = NULL;
533 	struct got_reflist_entry *new;
534 
535 	*newp = NULL;
536 
537 	new = malloc(sizeof(*new));
538 	if (new == NULL)
539 		return got_error_from_errno("malloc");
540 
541 	new->ref = got_ref_dup(re->ref);
542 	if (new->ref == NULL) {
543 		err = got_error_from_errno("got_ref_dup");
544 		free(new);
545 		return err;
546 	}
547 
548 	*newp = new;
549 	return NULL;
550 }
551 
552 const struct got_error *
553 got_ref_resolve_symbolic(struct got_reference **resolved,
554     struct got_repository *repo, struct got_reference *ref)
555 {
556 	struct got_reference *nextref;
557 	const struct got_error *err;
558 
559 	err = got_ref_open(&nextref, repo, ref->ref.symref.ref, 0);
560 	if (err)
561 		return err;
562 
563 	if (nextref->flags & GOT_REF_IS_SYMBOLIC)
564 		err = got_ref_resolve_symbolic(resolved, repo, nextref);
565 	else
566 		*resolved = got_ref_dup(nextref);
567 
568 	got_ref_close(nextref);
569 	return err;
570 }
571 
572 static const struct got_error *
573 ref_resolve(struct got_object_id **id, struct got_repository *repo,
574     struct got_reference *ref, int recursion)
575 {
576 	const struct got_error *err;
577 
578 	if (recursion <= 0)
579 		return got_error_msg(GOT_ERR_RECURSION,
580 		    "reference recursion limit reached");
581 
582 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
583 		struct got_reference *resolved = NULL;
584 		err = got_ref_resolve_symbolic(&resolved, repo, ref);
585 		if (err == NULL)
586 			err = ref_resolve(id, repo, resolved, --recursion);
587 		if (resolved)
588 			got_ref_close(resolved);
589 		return err;
590 	}
591 
592 	*id = calloc(1, sizeof(**id));
593 	if (*id == NULL)
594 		return got_error_from_errno("calloc");
595 	memcpy(*id, &ref->ref.ref.id, sizeof(**id));
596 	return NULL;
597 }
598 
599 const struct got_error *
600 got_ref_resolve(struct got_object_id **id, struct got_repository *repo,
601     struct got_reference *ref)
602 {
603 	return ref_resolve(id, repo, ref, GOT_REF_RECURSE_MAX);
604 }
605 
606 char *
607 got_ref_to_str(struct got_reference *ref)
608 {
609 	char *str;
610 
611 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
612 		return strdup(ref->ref.symref.ref);
613 
614 	if (got_object_id_str(&str, &ref->ref.ref.id) != NULL)
615 		return NULL;
616 
617 	return str;
618 }
619 
620 const char *
621 got_ref_get_name(struct got_reference *ref)
622 {
623 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
624 		return ref->ref.symref.name;
625 
626 	return ref->ref.ref.name;
627 }
628 
629 const char *
630 got_ref_get_symref_target(struct got_reference *ref)
631 {
632 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
633 		return ref->ref.symref.ref;
634 
635 	return NULL;
636 }
637 
638 time_t
639 got_ref_get_mtime(struct got_reference *ref)
640 {
641 	return ref->mtime;
642 }
643 
644 const struct got_error *
645 got_ref_cmp_by_name(void *arg, int *cmp, struct got_reference *re1,
646     struct got_reference* re2)
647 {
648 	const char *name1 = got_ref_get_name(re1);
649 	const char *name2 = got_ref_get_name(re2);
650 
651 	*cmp = got_path_cmp(name1, name2, strlen(name1), strlen(name2));
652 	return NULL;
653 }
654 
655 static const struct got_error *
656 get_committer_time(struct got_reference *ref, struct got_repository *repo)
657 {
658 	const struct got_error *err = NULL;
659 	int obj_type;
660 	struct got_commit_object *commit = NULL;
661 	struct got_tag_object *tag = NULL;
662 	struct got_object_id *id = NULL;
663 
664 	err = got_ref_resolve(&id, repo, ref);
665 	if (err)
666 		return err;
667 
668 	err = got_object_get_type(&obj_type, repo, id);
669 	if (err)
670 		goto done;
671 
672 	switch (obj_type) {
673 	case GOT_OBJ_TYPE_COMMIT:
674 		err = got_object_open_as_commit(&commit, repo, id);
675 		if (err)
676 			goto done;
677 		ref->committer_time =
678 		    got_object_commit_get_committer_time(commit);
679 		break;
680 	case GOT_OBJ_TYPE_TAG:
681 		err = got_object_open_as_tag(&tag, repo, id);
682 		if (err)
683 			goto done;
684 		ref->committer_time = got_object_tag_get_tagger_time(tag);
685 		break;
686 	default:
687 		/* best effort for other object types */
688 		ref->committer_time = got_ref_get_mtime(ref);
689 		break;
690 	}
691 done:
692 	free(id);
693 	if (commit)
694 		got_object_commit_close(commit);
695 	if (tag)
696 		got_object_tag_close(tag);
697 	return err;
698 }
699 
700 const struct got_error *
701 got_ref_cmp_tags(void *arg, int *cmp, struct got_reference *ref1,
702     struct got_reference *ref2)
703 {
704 	const struct got_error *err = NULL;
705 	struct got_repository *repo = arg;
706 
707 	*cmp = 0;
708 
709 	if (ref1->committer_time == 0) {
710 		err = get_committer_time(ref1, repo);
711 		if (err)
712 			return err;
713 	}
714 	if (ref2->committer_time == 0) {
715 		err = get_committer_time(ref2, repo);
716 		if (err)
717 			return err;
718 	}
719 
720 	/* Put latest tags first. */
721 	if (ref1->committer_time < ref2->committer_time)
722 		*cmp = 1;
723 	else if (ref1->committer_time > ref2->committer_time)
724 		*cmp = -1;
725 	else
726 		err = got_ref_cmp_by_name(NULL, cmp, ref2, ref1);
727 
728 	return err;
729 }
730 
731 const struct got_error *
732 got_ref_cmp_by_commit_timestamp_descending(void *arg, int *cmp,
733     struct got_reference *ref1, struct got_reference *ref2)
734 {
735 	const struct got_error *err = NULL;
736 	struct got_repository *repo = arg;
737 
738 	*cmp = 0;
739 
740 	if (ref1->committer_time == 0) {
741 		err = get_committer_time(ref1, repo);
742 		if (err)
743 			return err;
744 	}
745 	if (ref2->committer_time == 0) {
746 		err = get_committer_time(ref2, repo);
747 		if (err)
748 			return err;
749 	}
750 
751 	if (ref1->committer_time < ref2->committer_time)
752 		*cmp = 1;
753 	else if (ref2->committer_time < ref1->committer_time)
754 		*cmp = -1;
755 	else
756 		return got_ref_cmp_by_name(arg, cmp, ref1, ref2);
757 
758 	return err;
759 }
760 
761 const struct got_error *
762 got_reflist_insert(struct got_reflist_entry **newp,
763     struct got_reflist_head *refs, struct got_reference *ref,
764     got_ref_cmp_cb cmp_cb, void *cmp_arg)
765 {
766 	const struct got_error *err;
767 	struct got_reflist_entry *new, *re;
768 	int cmp;
769 
770 	*newp = NULL;
771 
772 	if (cmp_cb != got_ref_cmp_by_name && (ref->flags & GOT_REF_IS_PACKED)) {
773 		/*
774 		 * If we are not sorting elements by name then we must still
775 		 * detect collisions between a packed ref and an on-disk ref
776 		 * using the same name. On-disk refs take precedence and are
777 		 * already present on the list before packed refs get added.
778 		 */
779 		TAILQ_FOREACH(re, refs, entry) {
780 			err = got_ref_cmp_by_name(NULL, &cmp, re->ref, ref);
781 			if (err)
782 				return err;
783 			if (cmp == 0)
784 				return NULL;
785 		}
786 	}
787 
788 	new = malloc(sizeof(*new));
789 	if (new == NULL)
790 		return got_error_from_errno("malloc");
791 	new->ref = ref;
792 	*newp = new;
793 
794 	/*
795 	 * We must de-duplicate entries on insert because packed-refs may
796 	 * contain redundant entries. On-disk refs take precedence.
797 	 * This code assumes that on-disk revs are read before packed-refs.
798 	 * We're iterating the list anyway, so insert elements sorted by name.
799 	 *
800 	 * Many callers will provide paths in a somewhat sorted order.
801 	 * Iterating backwards from the tail of the list should be more
802 	 * efficient than traversing through the entire list each time
803 	 * an element is inserted.
804 	 */
805 	re = TAILQ_LAST(refs, got_reflist_head);
806 	while (re) {
807 		err = (*cmp_cb)(cmp_arg, &cmp, re->ref, new->ref);
808 		if (err)
809 			return err;
810 		if (cmp == 0) {
811 			/* duplicate */
812 			free(new);
813 			*newp = NULL;
814 			return NULL;
815 		} else if (cmp < 0) {
816 			TAILQ_INSERT_AFTER(refs, re, new, entry);
817 			return NULL;
818 		}
819 		re = TAILQ_PREV(re, got_reflist_head, entry);
820 	}
821 
822 	TAILQ_INSERT_HEAD(refs, new, entry);
823 	return NULL;
824 }
825 
826 const struct got_error *
827 got_reflist_sort(struct got_reflist_head *refs,
828     got_ref_cmp_cb cmp_cb, void *cmp_arg)
829 {
830 	const struct got_error *err = NULL;
831 	struct got_reflist_entry *re, *tmp, *new;
832 	struct got_reflist_head sorted;
833 
834 	TAILQ_INIT(&sorted);
835 
836 	TAILQ_FOREACH_SAFE(re, refs, entry, tmp) {
837 		struct got_reference *ref = re->ref;
838 		TAILQ_REMOVE(refs, re, entry);
839 		free(re);
840 		err = got_reflist_insert(&new, &sorted, ref, cmp_cb, cmp_arg);
841 		if (err || new == NULL /* duplicate */)
842 			got_ref_close(ref);
843 		if (err)
844 			return err;
845 	}
846 
847 	TAILQ_CONCAT(refs, &sorted, entry);
848 	return NULL;
849 }
850 
851 static const struct got_error *
852 gather_on_disk_refs(struct got_reflist_head *refs, const char *path_refs,
853     const char *subdir, struct got_repository *repo,
854     got_ref_cmp_cb cmp_cb, void *cmp_arg)
855 {
856 	const struct got_error *err = NULL;
857 	DIR *d = NULL;
858 	char *path_subdir;
859 	struct got_reference *ref;
860 	struct got_reflist_entry *new;
861 
862 	while (subdir[0] == '/')
863 		subdir++;
864 
865 	if (asprintf(&path_subdir, "%s/%s", path_refs, subdir) == -1)
866 		return got_error_from_errno("asprintf");
867 
868 	d = opendir(path_subdir);
869 	if (d == NULL) {
870 		char *refname;
871 
872 		if (errno != ENOTDIR)
873 			goto done;
874 
875 		/* This could be a regular on-disk reference file. */
876 		free(path_subdir);
877 		err = got_path_dirname(&path_subdir, subdir);
878 		if (err)
879 			return err;
880 		err = got_path_basename(&refname, subdir);
881 		if (err) {
882 			free(path_subdir);
883 			return err;
884 		}
885 		err = open_ref(&ref, path_refs, path_subdir, refname,
886 		    0, got_repo_get_object_format(repo));
887 		free(path_subdir);
888 		free(refname);
889 		if (err) {
890 			if (err->code == GOT_ERR_NOT_REF)
891 				return NULL;
892 			return err;
893 		}
894 		err = got_reflist_insert(&new, refs, ref,
895 		    cmp_cb, cmp_arg);
896 		if (err || new == NULL /* duplicate */)
897 			got_ref_close(ref);
898 		return err;
899 	}
900 
901 	for (;;) {
902 		struct dirent *dent;
903 		char *child;
904 		int type;
905 
906 		dent = readdir(d);
907 		if (dent == NULL)
908 			break;
909 
910 		if (strcmp(dent->d_name, ".") == 0 ||
911 		    strcmp(dent->d_name, "..") == 0)
912 			continue;
913 
914 		err = got_path_dirent_type(&type, path_subdir, dent);
915 		if (err)
916 			break;
917 
918 		switch (type) {
919 		case DT_REG:
920 			err = open_ref(&ref, path_refs, subdir, dent->d_name,
921 			    0, got_repo_get_object_format(repo));
922 			if (err && err->code == GOT_ERR_BAD_REF_NAME)
923 				break;
924 			if (err)
925 				goto done;
926 			if (ref) {
927 				err = got_reflist_insert(&new, refs, ref,
928 				    cmp_cb, cmp_arg);
929 				if (err || new == NULL /* duplicate */)
930 					got_ref_close(ref);
931 				if (err)
932 					goto done;
933 			}
934 			break;
935 		case DT_DIR:
936 			if (asprintf(&child, "%s%s%s", subdir,
937 			    subdir[0] == '\0' ? "" : "/", dent->d_name) == -1) {
938 				err = got_error_from_errno("asprintf");
939 				break;
940 			}
941 			err = gather_on_disk_refs(refs, path_refs, child, repo,
942 			    cmp_cb, cmp_arg);
943 			free(child);
944 			break;
945 		default:
946 			break;
947 		}
948 	}
949 done:
950 	if (d)
951 		closedir(d);
952 	free(path_subdir);
953 	return err;
954 }
955 
956 static int
957 match_packed_ref(struct got_reference *ref, const char *ref_namespace)
958 {
959 	const char *name = got_ref_get_name(ref);
960 	int namespace_is_absolute = (strncmp(ref_namespace, "refs/", 5) == 0);
961 
962 	if (namespace_is_absolute) {
963 		return (strcmp(name, ref_namespace) == 0 ||
964 		    got_path_is_child(name, ref_namespace,
965 		    strlen(ref_namespace)));
966 	}
967 
968 	/* Match all "subdirectories" as we do with on-disk refs. */
969 	while (*name != '\0') {
970 		while (*name == '/')
971 			name++;
972 		if (strcmp(name, ref_namespace) == 0 ||
973 		    got_path_is_child(name, ref_namespace,
974 		    strlen(ref_namespace)))
975 			return 1;
976 		while (*name != '\0' && *name != '/')
977 			name++;
978 	}
979 
980 	return 0;
981 }
982 
983 const struct got_error *
984 got_ref_list(struct got_reflist_head *refs, struct got_repository *repo,
985     const char *ref_namespace, got_ref_cmp_cb cmp_cb, void *cmp_arg)
986 {
987 	const struct got_error *err;
988 	char *packed_refs_path = NULL, *path_refs = NULL;
989 	char *abs_namespace = NULL, *buf = NULL;
990 	const char *ondisk_ref_namespace = NULL;
991 	char *line = NULL;
992 	FILE *f = NULL;
993 	struct got_reference *ref;
994 	struct got_reflist_entry *new;
995 
996 	if (ref_namespace == NULL || ref_namespace[0] == '\0') {
997 		path_refs = get_refs_dir_path(repo, GOT_REF_HEAD);
998 		if (path_refs == NULL) {
999 			err = got_error_from_errno("get_refs_dir_path");
1000 			goto done;
1001 		}
1002 		err = open_ref(&ref, path_refs, "", GOT_REF_HEAD, 0,
1003 		    got_repo_get_object_format(repo));
1004 		if (err)
1005 			goto done;
1006 		err = got_reflist_insert(&new, refs, ref, cmp_cb, cmp_arg);
1007 		if (err || new == NULL /* duplicate */)
1008 			got_ref_close(ref);
1009 		if (err && err->code != GOT_ERR_NOT_REF)
1010 			goto done;
1011 	} else {
1012 		/* Try listing a single reference. */
1013 		err = got_ref_open(&ref, repo, ref_namespace, 0);
1014 		if (err) {
1015 			if (err->code != GOT_ERR_NOT_REF)
1016 				goto done;
1017 			/* Try to look up references in a given namespace. */
1018 		} else {
1019 			err = got_reflist_insert(&new, refs, ref,
1020 			    cmp_cb, cmp_arg);
1021 			if (err || new == NULL /* duplicate */)
1022 				got_ref_close(ref);
1023 			return err;
1024 		}
1025 	}
1026 
1027 	if (ref_namespace) {
1028 		size_t len;
1029 		/* Canonicalize the path to eliminate double-slashes if any. */
1030 		if (asprintf(&abs_namespace, "/%s", ref_namespace) == -1) {
1031 			err = got_error_from_errno("asprintf");
1032 			goto done;
1033 		}
1034 		len = strlen(abs_namespace) + 1;
1035 		buf = malloc(len);
1036 		if (buf == NULL) {
1037 			err = got_error_from_errno("malloc");
1038 			goto done;
1039 		}
1040 		err = got_canonpath(abs_namespace, buf, len);
1041 		if (err)
1042 			goto done;
1043 		ondisk_ref_namespace = buf;
1044 		while (ondisk_ref_namespace[0] == '/')
1045 			ondisk_ref_namespace++;
1046 		if (strncmp(ondisk_ref_namespace, "refs/", 5) == 0)
1047 			ondisk_ref_namespace += 5;
1048 		else if (strcmp(ondisk_ref_namespace, "refs") == 0)
1049 			ondisk_ref_namespace = "";
1050 	}
1051 
1052 	/* Gather on-disk refs before parsing packed-refs. */
1053 	free(path_refs);
1054 	path_refs = get_refs_dir_path(repo, "");
1055 	if (path_refs == NULL) {
1056 		err = got_error_from_errno("get_refs_dir_path");
1057 		goto done;
1058 	}
1059 	err = gather_on_disk_refs(refs, path_refs,
1060 	    ondisk_ref_namespace ? ondisk_ref_namespace : "", repo,
1061 	    cmp_cb, cmp_arg);
1062 	if (err)
1063 		goto done;
1064 
1065 	/*
1066 	 * The packed-refs file may contain redundant entries, in which
1067 	 * case on-disk refs take precedence.
1068 	 */
1069 	packed_refs_path = got_repo_get_path_packed_refs(repo);
1070 	if (packed_refs_path == NULL) {
1071 		err = got_error_from_errno("got_repo_get_path_packed_refs");
1072 		goto done;
1073 	}
1074 
1075 	f = fopen(packed_refs_path, "re");
1076 	if (f) {
1077 		size_t linesize = 0;
1078 		ssize_t linelen;
1079 		struct stat sb;
1080 
1081 		if (fstat(fileno(f), &sb) == -1) {
1082 			err = got_error_from_errno2("fstat", packed_refs_path);
1083 			goto done;
1084 		}
1085 		for (;;) {
1086 			linelen = getline(&line, &linesize, f);
1087 			if (linelen == -1) {
1088 				if (feof(f))
1089 					break;
1090 				err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
1091 				goto done;
1092 			}
1093 			if (linelen > 0 && line[linelen - 1] == '\n')
1094 				line[linelen - 1] = '\0';
1095 			err = parse_packed_ref_line(&ref, NULL, line,
1096 			    sb.st_mtime, got_repo_get_object_format(repo));
1097 			if (err)
1098 				goto done;
1099 			if (ref) {
1100 				if (ref_namespace &&
1101 				    !match_packed_ref(ref, ref_namespace)) {
1102 					got_ref_close(ref);
1103 					continue;
1104 				}
1105 				err = got_reflist_insert(&new, refs, ref,
1106 				    cmp_cb, cmp_arg);
1107 				if (err || new == NULL /* duplicate */)
1108 					got_ref_close(ref);
1109 				if (err)
1110 					goto done;
1111 			}
1112 		}
1113 	}
1114 done:
1115 	free(packed_refs_path);
1116 	free(abs_namespace);
1117 	free(buf);
1118 	free(line);
1119 	free(path_refs);
1120 	if (f && fclose(f) == EOF && err == NULL)
1121 		err = got_error_from_errno("fclose");
1122 	return err;
1123 }
1124 
1125 void
1126 got_ref_list_free(struct got_reflist_head *refs)
1127 {
1128 	struct got_reflist_entry *re;
1129 
1130 	while ((re = TAILQ_FIRST(refs))) {
1131 		TAILQ_REMOVE(refs, re, entry);
1132 		got_ref_close(re->ref);
1133 		free(re);
1134 	}
1135 }
1136 
1137 int
1138 got_ref_is_symbolic(struct got_reference *ref)
1139 {
1140 	return (ref->flags & GOT_REF_IS_SYMBOLIC);
1141 }
1142 
1143 const struct got_error *
1144 got_ref_change_ref(struct got_reference *ref, struct got_object_id *id)
1145 {
1146 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
1147 		return got_error(GOT_ERR_BAD_REF_TYPE);
1148 
1149 	memcpy(&ref->ref.ref.id, id, sizeof(ref->ref.ref.id));
1150 	return NULL;
1151 }
1152 
1153 const struct got_error *
1154 got_ref_change_symref(struct got_reference *ref, const char *refname)
1155 {
1156 	char *new_name;
1157 
1158 	if ((ref->flags & GOT_REF_IS_SYMBOLIC) == 0)
1159 		return got_error(GOT_ERR_BAD_REF_TYPE);
1160 
1161 	new_name = strdup(refname);
1162 	if (new_name == NULL)
1163 		return got_error_from_errno("strdup");
1164 
1165 	free(ref->ref.symref.ref);
1166 	ref->ref.symref.ref = new_name;
1167 	return NULL;
1168 }
1169 
1170 const struct got_error *
1171 got_ref_change_symref_to_ref(struct got_reference *symref,
1172     struct got_object_id *id)
1173 {
1174 	if ((symref->flags & GOT_REF_IS_SYMBOLIC) == 0)
1175 		return got_error(GOT_ERR_BAD_REF_TYPE);
1176 
1177 	symref->ref.ref.name = symref->ref.symref.name;
1178 	memcpy(&symref->ref.ref.id, id, sizeof(symref->ref.ref.id));
1179 	symref->flags &= ~GOT_REF_IS_SYMBOLIC;
1180 	return NULL;
1181 }
1182 
1183 const struct got_error *
1184 got_ref_write(struct got_reference *ref, struct got_repository *repo)
1185 {
1186 	const struct got_error *err = NULL, *unlock_err = NULL;
1187 	const char *name = got_ref_get_name(ref);
1188 	char *path_refs = NULL, *path = NULL, *tmppath = NULL;
1189 	struct got_lockfile *lf = NULL;
1190 	FILE *f = NULL;
1191 	size_t n;
1192 	struct stat sb;
1193 
1194 	path_refs = get_refs_dir_path(repo, name);
1195 	if (path_refs == NULL) {
1196 		err = got_error_from_errno2("get_refs_dir_path", name);
1197 		goto done;
1198 	}
1199 
1200 	if (asprintf(&path, "%s/%s", path_refs, name) == -1) {
1201 		err = got_error_from_errno("asprintf");
1202 		goto done;
1203 	}
1204 
1205 	err = got_opentemp_named(&tmppath, &f, path, "");
1206 	if (err) {
1207 		char *parent;
1208 		if (!(err->code == GOT_ERR_ERRNO && errno == ENOENT))
1209 			goto done;
1210 		err = got_path_dirname(&parent, path);
1211 		if (err)
1212 			goto done;
1213 		err = got_path_mkdir(parent);
1214 		free(parent);
1215 		if (err)
1216 			goto done;
1217 		err = got_opentemp_named(&tmppath, &f, path, "");
1218 		if (err)
1219 			goto done;
1220 	}
1221 
1222 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
1223 		n = fprintf(f, "ref: %s\n", ref->ref.symref.ref);
1224 		if (n != strlen(ref->ref.symref.ref) + 6) {
1225 			err = got_ferror(f, GOT_ERR_IO);
1226 			goto done;
1227 		}
1228 	} else {
1229 		char *hex;
1230 		size_t len;
1231 
1232 		err = got_object_id_str(&hex, &ref->ref.ref.id);
1233 		if (err)
1234 			goto done;
1235 		len = strlen(hex);
1236 		n = fprintf(f, "%s\n", hex);
1237 		free(hex);
1238 		if (n != len + 1) {
1239 			err = got_ferror(f, GOT_ERR_IO);
1240 			goto done;
1241 		}
1242 	}
1243 
1244 	if (ref->lf == NULL) {
1245 		err = got_lockfile_lock(&lf, path, -1);
1246 		if (err)
1247 			goto done;
1248 	}
1249 
1250 	/* XXX: check if old content matches our expectations? */
1251 
1252 	if (stat(path, &sb) != 0) {
1253 		if (errno != ENOENT) {
1254 			err = got_error_from_errno2("stat", path);
1255 			goto done;
1256 		}
1257 		sb.st_mode = GOT_DEFAULT_FILE_MODE;
1258 	}
1259 
1260 	if (fchmod(fileno(f), sb.st_mode) != 0) {
1261 		err = got_error_from_errno2("fchmod", tmppath);
1262 		goto done;
1263 	}
1264 
1265 	if (rename(tmppath, path) != 0) {
1266 		err = got_error_from_errno3("rename", tmppath, path);
1267 		goto done;
1268 	}
1269 	free(tmppath);
1270 	tmppath = NULL;
1271 
1272 	if (stat(path, &sb) == -1) {
1273 		err = got_error_from_errno2("stat", path);
1274 		goto done;
1275 	}
1276 	ref->mtime = sb.st_mtime;
1277 done:
1278 	if (ref->lf == NULL && lf)
1279 		unlock_err = got_lockfile_unlock(lf, -1);
1280 	if (f) {
1281 		if (fclose(f) == EOF && err == NULL)
1282 			err = got_error_from_errno("fclose");
1283 	}
1284 	free(path_refs);
1285 	free(path);
1286 	if (tmppath) {
1287 		if (unlink(tmppath) == -1 && err == NULL)
1288 			err = got_error_from_errno2("unlink", tmppath);
1289 		free(tmppath);
1290 	}
1291 	return err ? err : unlock_err;
1292 }
1293 
1294 static const struct got_error *
1295 delete_packed_ref(struct got_reference *delref, struct got_repository *repo)
1296 {
1297 	const struct got_error *err = NULL, *unlock_err = NULL;
1298 	struct got_lockfile *lf = NULL;
1299 	FILE *f = NULL, *tmpf = NULL;
1300 	char *line = NULL, *packed_refs_path, *tmppath = NULL;
1301 	size_t linesize = 0;
1302 	struct got_reflist_head refs;
1303 	int found_delref = 0;
1304 
1305 	/* The packed-refs file does not cotain symbolic references. */
1306 	if (delref->flags & GOT_REF_IS_SYMBOLIC)
1307 		return got_error(GOT_ERR_BAD_REF_DATA);
1308 
1309 	TAILQ_INIT(&refs);
1310 
1311 	packed_refs_path = got_repo_get_path_packed_refs(repo);
1312 	if (packed_refs_path == NULL)
1313 		return got_error_from_errno("got_repo_get_path_packed_refs");
1314 
1315 	err = got_opentemp_named(&tmppath, &tmpf, packed_refs_path, "");
1316 	if (err)
1317 		goto done;
1318 
1319 	if (delref->lf == NULL) {
1320 		err = got_lockfile_lock(&lf, packed_refs_path, -1);
1321 		if (err)
1322 			goto done;
1323 	}
1324 
1325 	f = fopen(packed_refs_path, "re");
1326 	if (f == NULL) {
1327 		err = got_error_from_errno2("fopen", packed_refs_path);
1328 		goto done;
1329 	}
1330 	for (;;) {
1331 		ssize_t linelen;
1332 		struct got_reference *ref;
1333 		struct got_reflist_entry *new;
1334 
1335 		linelen = getline(&line, &linesize, f);
1336 		if (linelen == -1) {
1337 			if (feof(f))
1338 				break;
1339 			err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
1340 			goto done;
1341 		}
1342 		if (linelen > 0 && line[linelen - 1] == '\n')
1343 			line[linelen - 1] = '\0';
1344 		err = parse_packed_ref_line(&ref, NULL, line, 0,
1345 		    got_repo_get_object_format(repo));
1346 		if (err)
1347 			goto done;
1348 		if (ref == NULL)
1349 			continue;
1350 
1351 		if (strcmp(ref->ref.ref.name, delref->ref.ref.name) == 0 &&
1352 		    got_object_id_cmp(&ref->ref.ref.id,
1353 		    &delref->ref.ref.id) == 0) {
1354 			found_delref = 1;
1355 			got_ref_close(ref);
1356 			continue;
1357 		}
1358 
1359 		err = got_reflist_insert(&new, &refs, ref,
1360 		    got_ref_cmp_by_name, NULL);
1361 		if (err || new == NULL /* duplicate */)
1362 			got_ref_close(ref);
1363 		if (err)
1364 			goto done;
1365 	}
1366 
1367 	if (found_delref) {
1368 		struct got_reflist_entry *re;
1369 		size_t n;
1370 		struct stat sb;
1371 
1372 		n = fprintf(tmpf, "%s\n", GOT_PACKED_REFS_HEADER);
1373 		if (n != sizeof(GOT_PACKED_REFS_HEADER)) {
1374 			err = got_ferror(f, GOT_ERR_IO);
1375 			goto done;
1376 		}
1377 
1378 		TAILQ_FOREACH(re, &refs, entry) {
1379 			char *hex;
1380 			size_t len;
1381 
1382 			err = got_object_id_str(&hex, &re->ref->ref.ref.id);
1383 			if (err)
1384 				goto done;
1385 			len = strlen(hex);
1386 			n = fprintf(tmpf, "%s ", hex);
1387 			free(hex);
1388 			if (n != len + 1) {
1389 				err = got_ferror(f, GOT_ERR_IO);
1390 				goto done;
1391 			}
1392 
1393 			n = fprintf(tmpf, "%s\n", re->ref->ref.ref.name);
1394 			if (n != strlen(re->ref->ref.ref.name) + 1) {
1395 				err = got_ferror(f, GOT_ERR_IO);
1396 				goto done;
1397 			}
1398 		}
1399 
1400 		if (fflush(tmpf) != 0) {
1401 			err = got_error_from_errno("fflush");
1402 			goto done;
1403 		}
1404 
1405 		if (fstat(fileno(f), &sb) != 0) {
1406 			if (errno != ENOENT) {
1407 				err = got_error_from_errno2("fstat",
1408 				    packed_refs_path);
1409 				goto done;
1410 			}
1411 			sb.st_mode = GOT_DEFAULT_FILE_MODE;
1412 		}
1413 
1414 		if (fchmod(fileno(tmpf), sb.st_mode) != 0) {
1415 			err = got_error_from_errno2("fchmod", tmppath);
1416 			goto done;
1417 		}
1418 
1419 		if (rename(tmppath, packed_refs_path) != 0) {
1420 			err = got_error_from_errno3("rename", tmppath,
1421 			    packed_refs_path);
1422 			goto done;
1423 		}
1424 		free(tmppath);
1425 		tmppath = NULL;
1426 	}
1427 done:
1428 	if (delref->lf == NULL && lf)
1429 		unlock_err = got_lockfile_unlock(lf, -1);
1430 	if (f) {
1431 		if (fclose(f) == EOF && err == NULL)
1432 			err = got_error_from_errno("fclose");
1433 	}
1434 	if (tmppath && unlink(tmppath) == -1 && err == NULL)
1435 		err = got_error_from_errno2("unlink", tmppath);
1436 	if (tmpf && fclose(tmpf) == EOF && err == NULL)
1437 		err = got_error_from_errno("fclose");
1438 	free(tmppath);
1439 	free(packed_refs_path);
1440 	free(line);
1441 	got_ref_list_free(&refs);
1442 	return err ? err : unlock_err;
1443 }
1444 
1445 static const struct got_error *
1446 delete_loose_ref(struct got_reference *ref, struct got_repository *repo)
1447 {
1448 	const struct got_error *err = NULL, *unlock_err = NULL;
1449 	const char *name = got_ref_get_name(ref);
1450 	char *path_refs = NULL, *path = NULL;
1451 	struct got_lockfile *lf = NULL;
1452 
1453 	path_refs = get_refs_dir_path(repo, name);
1454 	if (path_refs == NULL) {
1455 		err = got_error_from_errno2("get_refs_dir_path", name);
1456 		goto done;
1457 	}
1458 
1459 	if (asprintf(&path, "%s/%s", path_refs, name) == -1) {
1460 		err = got_error_from_errno("asprintf");
1461 		goto done;
1462 	}
1463 
1464 	if (ref->lf == NULL) {
1465 		err = got_lockfile_lock(&lf, path, -1);
1466 		if (err)
1467 			goto done;
1468 	}
1469 
1470 	/* XXX: check if old content matches our expectations? */
1471 
1472 	if (unlink(path) == -1)
1473 		err = got_error_from_errno2("unlink", path);
1474 done:
1475 	if (ref->lf == NULL && lf)
1476 		unlock_err = got_lockfile_unlock(lf, -1);
1477 
1478 	free(path_refs);
1479 	free(path);
1480 	return err ? err : unlock_err;
1481 }
1482 
1483 const struct got_error *
1484 got_ref_delete(struct got_reference *ref, struct got_repository *repo)
1485 {
1486 	const struct got_error *err = NULL;
1487 	struct got_reference *ref2;
1488 
1489 	if (ref->flags & GOT_REF_IS_PACKED) {
1490 		err = delete_packed_ref(ref, repo);
1491 		if (err)
1492 			return err;
1493 
1494 		err = got_ref_open(&ref2, repo, got_ref_get_name(ref), 0);
1495 		if (err) {
1496 			if (err->code == GOT_ERR_NOT_REF)
1497 				return NULL;
1498 			return err;
1499 		}
1500 
1501 		err = delete_loose_ref(ref2, repo);
1502 		got_ref_close(ref2);
1503 		return err;
1504 	} else {
1505 		err = delete_loose_ref(ref, repo);
1506 		if (err)
1507 			return err;
1508 
1509 		err = got_ref_open(&ref2, repo, got_ref_get_name(ref), 0);
1510 		if (err) {
1511 			if (err->code == GOT_ERR_NOT_REF)
1512 				return NULL;
1513 			return err;
1514 		}
1515 
1516 		err = delete_packed_ref(ref2, repo);
1517 		got_ref_close(ref2);
1518 		return err;
1519 	}
1520 }
1521 
1522 const struct got_error *
1523 got_ref_unlock(struct got_reference *ref)
1524 {
1525 	const struct got_error *err;
1526 	err = got_lockfile_unlock(ref->lf, -1);
1527 	ref->lf = NULL;
1528 	return err;
1529 }
1530 
1531 struct got_reflist_object_id_map {
1532 	struct got_object_idset *idset;
1533 };
1534 
1535 struct got_reflist_object_id_map_entry {
1536 	struct got_reflist_head refs;
1537 };
1538 
1539 static const struct got_error *
1540 add_object_id_map_entry(struct got_object_idset *idset,
1541     struct got_object_id *id, struct got_reflist_entry *re)
1542 {
1543 	const struct got_error *err = NULL;
1544 	struct got_reflist_object_id_map_entry *ent;
1545 	struct got_reflist_entry *new;
1546 
1547 	ent = got_object_idset_get(idset, id);
1548 	if (ent == NULL) {
1549 		ent = malloc(sizeof(*ent));
1550 		if (ent == NULL)
1551 			return got_error_from_errno("malloc");
1552 
1553 		TAILQ_INIT(&ent->refs);
1554 		err = got_object_idset_add(idset, id, ent);
1555 		if (err) {
1556 			free(ent);
1557 			return err;
1558 		}
1559 	}
1560 
1561 	err = got_reflist_entry_dup(&new, re);
1562 	if (err)
1563 		return err;
1564 
1565 	TAILQ_INSERT_TAIL(&ent->refs, new, entry);
1566 	return NULL;
1567 }
1568 
1569 const struct got_error *
1570 got_reflist_object_id_map_create(struct got_reflist_object_id_map **map,
1571     struct got_reflist_head *refs, struct got_repository *repo)
1572 {
1573 	const struct got_error *err = NULL;
1574 	struct got_object_idset *idset;
1575 	struct got_object_id *id = NULL;
1576 	struct got_reflist_entry *re;
1577 
1578 	idset = got_object_idset_alloc();
1579 	if (idset == NULL)
1580 		return got_error_from_errno("got_object_idset_alloc");
1581 
1582 	*map = malloc(sizeof(**map));
1583 	if (*map == NULL) {
1584 		got_object_idset_free(idset);
1585 		return got_error_from_errno("malloc");
1586 	}
1587 	(*map)->idset = idset;
1588 
1589 	TAILQ_FOREACH(re, refs, entry) {
1590 		struct got_tag_object *tag = NULL;
1591 
1592 		err = got_ref_resolve(&id, repo, re->ref);
1593 		if (err)
1594 			goto done;
1595 
1596 		err = add_object_id_map_entry(idset, id, re);
1597 		if (err)
1598 			goto done;
1599 
1600 		if (strstr(got_ref_get_name(re->ref), "/tags/") == NULL) {
1601 			free(id);
1602 			id = NULL;
1603 			continue;
1604 		}
1605 
1606 		err = got_object_open_as_tag(&tag, repo, id);
1607 		if (err) {
1608 			if (err->code != GOT_ERR_OBJ_TYPE)
1609 				goto done;
1610 			/* Ref points at something other than a tag. */
1611 			err = NULL;
1612 			tag = NULL;
1613 			free(id);
1614 			id = NULL;
1615 			continue;
1616 		}
1617 
1618 		err = add_object_id_map_entry(idset,
1619 		    got_object_tag_get_object_id(tag), re);
1620 		got_object_tag_close(tag);
1621 		if (err)
1622 			goto done;
1623 
1624 		free(id);
1625 		id = NULL;
1626 	}
1627 done:
1628 	free(id);
1629 	if (err) {
1630 		got_reflist_object_id_map_free(*map);
1631 		*map = NULL;
1632 	}
1633 	return err;
1634 }
1635 
1636 struct got_reflist_head *
1637 got_reflist_object_id_map_lookup(struct got_reflist_object_id_map *map,
1638     struct got_object_id *id)
1639 {
1640 	struct got_reflist_object_id_map_entry *ent;
1641 	ent = got_object_idset_get(map->idset, id);
1642 	if (ent)
1643 		return &ent->refs;
1644 	return NULL;
1645 }
1646 
1647 static const struct got_error *
1648 free_id_map_entry(struct got_object_id *id, void *data, void *arg)
1649 {
1650 	struct got_reflist_object_id_map_entry *ent = data;
1651 
1652 	got_ref_list_free(&ent->refs);
1653 	free(ent);
1654 	return NULL;
1655 }
1656 
1657 void
1658 got_reflist_object_id_map_free(struct got_reflist_object_id_map *map)
1659 {
1660 	got_object_idset_for_each(map->idset, free_id_map_entry, NULL);
1661 	got_object_idset_free(map->idset);
1662 	free(map);
1663 }