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 	/* Cached timestamp for got_ref_cmp_by_commit_timestamp_descending() */
92 	time_t committer_time;
93 };
94 
95 static const struct got_error *
96 alloc_ref(struct got_reference **ref, const char *name,
97     struct got_object_id *id, int flags, time_t mtime)
98 {
99 	const struct got_error *err = NULL;
100 
101 	*ref = calloc(1, sizeof(**ref));
102 	if (*ref == NULL)
103 		return got_error_from_errno("calloc");
104 
105 	memcpy(&(*ref)->ref.ref.id, id, sizeof((*ref)->ref.ref.id));
106 	(*ref)->flags = flags;
107 	(*ref)->ref.ref.name = strdup(name);
108 	(*ref)->mtime = mtime;
109 	if ((*ref)->ref.ref.name == NULL) {
110 		err = got_error_from_errno("strdup");
111 		got_ref_close(*ref);
112 		*ref = NULL;
113 	}
114 	return err;
115 }
116 
117 static const struct got_error *
118 alloc_symref(struct got_reference **ref, const char *name,
119     const char *target_ref, int flags)
120 {
121 	const struct got_error *err = NULL;
122 
123 	*ref = calloc(1, sizeof(**ref));
124 	if (*ref == NULL)
125 		return got_error_from_errno("calloc");
126 
127 	(*ref)->flags = GOT_REF_IS_SYMBOLIC | flags;
128 	(*ref)->ref.symref.name = strdup(name);
129 	if ((*ref)->ref.symref.name == NULL) {
130 		err = got_error_from_errno("strdup");
131 		got_ref_close(*ref);
132 		*ref = NULL;
133 		return err;
134 	}
135 	(*ref)->ref.symref.ref = strdup(target_ref);
136 	if ((*ref)->ref.symref.ref == NULL) {
137 		err = got_error_from_errno("strdup");
138 		got_ref_close(*ref);
139 		*ref = NULL;
140 	}
141 	return err;
142 }
143 
144 static const struct got_error *
145 parse_symref(struct got_reference **ref, const char *name, const char *line)
146 {
147 	if (line[0] == '\0')
148 		return got_error(GOT_ERR_BAD_REF_DATA);
149 
150 	return alloc_symref(ref, name, line, 0);
151 }
152 
153 static const struct got_error *
154 parse_ref_line(struct got_reference **ref, const char *name, const char *line,
155     time_t mtime, enum got_hash_algorithm algo)
156 {
157 	struct got_object_id id;
158 
159 	if (strncmp(line, "ref: ", 5) == 0) {
160 		line += 5;
161 		return parse_symref(ref, name, line);
162 	}
163 
164 	if (!got_parse_object_id(&id, line, algo))
165 		return got_error(GOT_ERR_BAD_REF_DATA);
166 
167 	return alloc_ref(ref, name, &id, 0, mtime);
168 }
169 
170 static const struct got_error *
171 parse_ref_file(struct got_reference **ref, const char *name,
172     const char *absname, const char *abspath, int lock,
173     enum got_hash_algorithm algo)
174 {
175 	const struct got_error *err = NULL;
176 	FILE *f;
177 	char *line = NULL;
178 	size_t linesize = 0;
179 	ssize_t linelen;
180 	struct got_lockfile *lf = NULL;
181 	struct stat sb;
182 
183 	if (lock) {
184 		err = got_lockfile_lock(&lf, abspath, -1);
185 		if (err) {
186 			if (err->code == GOT_ERR_ERRNO && errno == ENOENT)
187 				err = got_error_not_ref(name);
188 			return err;
189 		}
190 	}
191 
192 	f = fopen(abspath, "rbe");
193 	if (f == NULL) {
194 		if (errno != ENOTDIR && errno != ENOENT)
195 			err = got_error_from_errno2("fopen", abspath);
196 		else
197 			err = got_error_not_ref(name);
198 		if (lock)
199 			got_lockfile_unlock(lf, -1);
200 		return err;
201 	}
202 	if (fstat(fileno(f), &sb) == -1) {
203 		err = got_error_from_errno2("fstat", abspath);
204 		goto done;
205 	}
206 
207 	linelen = getline(&line, &linesize, f);
208 	if (linelen == -1) {
209 		if (feof(f))
210 			err = NULL; /* ignore empty files (could be locks) */
211 		else {
212 			if (errno == EISDIR)
213 				err = got_error(GOT_ERR_NOT_REF);
214 			else if (ferror(f))
215 				err = got_ferror(f, GOT_ERR_IO);
216 			else
217 				err = got_error_from_errno2("getline", abspath);
218 		}
219 		if (lock)
220 			got_lockfile_unlock(lf, -1);
221 		goto done;
222 	}
223 	while (linelen > 0 && line[linelen - 1] == '\n') {
224 		line[linelen - 1] = '\0';
225 		linelen--;
226 	}
227 
228 	err = parse_ref_line(ref, absname, line, sb.st_mtime, algo);
229 	if (lock) {
230 		if (err)
231 			got_lockfile_unlock(lf, -1);
232 		else {
233 			if (*ref)
234 				(*ref)->lf = lf;
235 			else
236 				got_lockfile_unlock(lf, -1);
237 		}
238 	}
239 done:
240 	free(line);
241 	if (fclose(f) == EOF && err == NULL) {
242 		err = got_error_from_errno("fclose");
243 		if (*ref) {
244 			if (lock)
245 				got_ref_unlock(*ref);
246 			got_ref_close(*ref);
247 			*ref = NULL;
248 		}
249 	}
250 	return err;
251 }
252 
253 static int
254 is_well_known_ref(const char *refname)
255 {
256 	return (strcmp(refname, GOT_REF_HEAD) == 0 ||
257 	    strcmp(refname, GOT_REF_ORIG_HEAD) == 0 ||
258 	    strcmp(refname, GOT_REF_MERGE_HEAD) == 0 ||
259 	    strcmp(refname, GOT_REF_FETCH_HEAD) == 0);
260 }
261 
262 static char *
263 get_refs_dir_path(struct got_repository *repo, const char *refname)
264 {
265 	if (is_well_known_ref(refname) || strncmp(refname, "refs/", 5) == 0)
266 		return strdup(got_repo_get_path_git_dir(repo));
267 
268 	return got_repo_get_path_refs(repo);
269 }
270 
271 const struct got_error *
272 got_ref_alloc(struct got_reference **ref, const char *name,
273     struct got_object_id *id)
274 {
275 	if (!got_ref_name_is_valid(name))
276 		return got_error_path(name, GOT_ERR_BAD_REF_NAME);
277 
278 	return alloc_ref(ref, name, id, 0, 0);
279 }
280 
281 const struct got_error *
282 got_ref_alloc_symref(struct got_reference **ref, const char *name,
283 	struct got_reference *target_ref)
284 {
285 	if (!got_ref_name_is_valid(name))
286 		return got_error_path(name, GOT_ERR_BAD_REF_NAME);
287 
288 	return alloc_symref(ref, name, got_ref_get_name(target_ref), 0);
289 }
290 
291 static const struct got_error *
292 parse_packed_ref_line(struct got_reference **ref, const char *abs_refname,
293     const char *line, time_t mtime, enum got_hash_algorithm algo)
294 {
295 	struct got_object_id id;
296 	const char *name;
297 
298 	*ref = NULL;
299 
300 	if (line[0] == '#' || line[0] == '^')
301 		return NULL;
302 
303 	if (!got_parse_object_id(&id, line, algo))
304 		return got_error(GOT_ERR_BAD_REF_DATA);
305 
306 	if (abs_refname) {
307 		if (strcmp(line + SHA1_DIGEST_STRING_LENGTH, abs_refname) != 0)
308 			return NULL;
309 		name = abs_refname;
310 	} else
311 		name = line + SHA1_DIGEST_STRING_LENGTH;
312 
313 	return alloc_ref(ref, name, &id, GOT_REF_IS_PACKED, mtime);
314 }
315 
316 static const struct got_error *
317 open_packed_ref(struct got_reference **ref, FILE *f, const char **subdirs,
318     int nsubdirs, const char *refname, time_t mtime,
319     enum got_hash_algorithm algo)
320 {
321 	const struct got_error *err = NULL;
322 	char *abs_refname;
323 	char *line = NULL;
324 	size_t linesize = 0;
325 	ssize_t linelen;
326 	int i, ref_is_absolute = (strncmp(refname, "refs/", 5) == 0);
327 
328 	*ref = NULL;
329 
330 	if (ref_is_absolute)
331 		abs_refname = (char *)refname;
332 	do {
333 		linelen = getline(&line, &linesize, f);
334 		if (linelen == -1) {
335 			if (feof(f))
336 				break;
337 			err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
338 			break;
339 		}
340 		if (linelen > 0 && line[linelen - 1] == '\n')
341 			line[linelen - 1] = '\0';
342 		for (i = 0; i < nsubdirs; i++) {
343 			if (!ref_is_absolute &&
344 			    asprintf(&abs_refname, "refs/%s/%s", subdirs[i],
345 			    refname) == -1)
346 				return got_error_from_errno("asprintf");
347 			err = parse_packed_ref_line(ref, abs_refname, line,
348 			    mtime, algo);
349 			if (!ref_is_absolute)
350 				free(abs_refname);
351 			if (err || *ref != NULL)
352 				break;
353 		}
354 		if (err)
355 			break;
356 	} while (*ref == NULL);
357 	free(line);
358 
359 	return err;
360 }
361 
362 static const struct got_error *
363 open_ref(struct got_reference **ref, const char *path_refs, const char *subdir,
364     const char *name, int lock, enum got_hash_algorithm algo)
365 {
366 	const struct got_error *err = NULL;
367 	char *path = NULL;
368 	char *absname = NULL;
369 	int ref_is_absolute = (strncmp(name, "refs/", 5) == 0);
370 	int ref_is_well_known = (subdir[0] == '\0' && is_well_known_ref(name));
371 
372 	*ref = NULL;
373 
374 	if (!got_ref_name_is_valid(name))
375 		return got_error_path(name, GOT_ERR_BAD_REF_NAME);
376 
377 	if (ref_is_absolute || ref_is_well_known) {
378 		if (asprintf(&path, "%s/%s", path_refs, name) == -1)
379 			return got_error_from_errno("asprintf");
380 		absname = (char *)name;
381 	} else {
382 		if (asprintf(&path, "%s/%s%s%s", path_refs, subdir,
383 		    subdir[0] ? "/" : "", name) == -1)
384 			return got_error_from_errno("asprintf");
385 
386 		if (asprintf(&absname, "refs/%s%s%s",
387 		    subdir, subdir[0] ? "/" : "", name) == -1) {
388 			err = got_error_from_errno("asprintf");
389 			goto done;
390 		}
391 	}
392 
393 	err = parse_ref_file(ref, name, absname, path, lock, algo);
394 done:
395 	if (!ref_is_absolute && !ref_is_well_known)
396 		free(absname);
397 	free(path);
398 	return err;
399 }
400 
401 const struct got_error *
402 got_ref_open(struct got_reference **ref, struct got_repository *repo,
403     const char *refname, int lock)
404 {
405 	const struct got_error *err = NULL;
406 	char *packed_refs_path = NULL, *path_refs = NULL;
407 	const char *subdirs[] = {
408 	    GOT_REF_HEADS, GOT_REF_TAGS, GOT_REF_REMOTES
409 	};
410 	size_t i;
411 	int well_known = is_well_known_ref(refname);
412 	struct got_lockfile *lf = NULL;
413 
414 	*ref = NULL;
415 
416 	path_refs = get_refs_dir_path(repo, refname);
417 	if (path_refs == NULL) {
418 		err = got_error_from_errno2("get_refs_dir_path", refname);
419 		goto done;
420 	}
421 
422 	if (well_known) {
423 		err = open_ref(ref, path_refs, "", refname, lock,
424 		    got_repo_get_object_format(repo));
425 	} else {
426 		FILE *f;
427 
428 		/* Search on-disk refs before packed refs! */
429 		for (i = 0; i < nitems(subdirs); i++) {
430 			err = open_ref(ref, path_refs, subdirs[i], refname,
431 			    lock, got_repo_get_object_format(repo));
432 			if ((err && err->code != GOT_ERR_NOT_REF) || *ref)
433 				goto done;
434 		}
435 
436 		packed_refs_path = got_repo_get_path_packed_refs(repo);
437 		if (packed_refs_path == NULL) {
438 			err = got_error_from_errno(
439 			    "got_repo_get_path_packed_refs");
440 			goto done;
441 		}
442 
443 		if (lock) {
444 			err = got_lockfile_lock(&lf, packed_refs_path, -1);
445 			if (err)
446 				goto done;
447 		}
448 		f = fopen(packed_refs_path, "rbe");
449 		if (f != NULL) {
450 			struct stat sb;
451 			if (fstat(fileno(f), &sb) == -1) {
452 				err = got_error_from_errno2("fstat",
453 				    packed_refs_path);
454 				goto done;
455 			}
456 			err = open_packed_ref(ref, f, subdirs, nitems(subdirs),
457 			    refname, sb.st_mtime,
458 			    got_repo_get_object_format(repo));
459 			if (!err) {
460 				if (fclose(f) == EOF) {
461 					err = got_error_from_errno("fclose");
462 					got_ref_close(*ref);
463 					*ref = NULL;
464 				} else if (*ref)
465 					(*ref)->lf = lf;
466 			}
467 		}
468 	}
469 done:
470 	if (!err && *ref == NULL)
471 		err = got_error_not_ref(refname);
472 	if (err && lf)
473 		got_lockfile_unlock(lf, -1);
474 	free(packed_refs_path);
475 	free(path_refs);
476 	return err;
477 }
478 
479 void
480 got_ref_close(struct got_reference *ref)
481 {
482 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
483 		free(ref->ref.symref.name);
484 		free(ref->ref.symref.ref);
485 	} else
486 		free(ref->ref.ref.name);
487 	free(ref);
488 }
489 
490 struct got_reference *
491 got_ref_dup(struct got_reference *ref)
492 {
493 	struct got_reference *ret;
494 
495 	ret = calloc(1, sizeof(*ret));
496 	if (ret == NULL)
497 		return NULL;
498 
499 	ret->flags = ref->flags;
500 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
501 		ret->ref.symref.name = strdup(ref->ref.symref.name);
502 		if (ret->ref.symref.name == NULL) {
503 			free(ret);
504 			return NULL;
505 		}
506 		ret->ref.symref.ref = strdup(ref->ref.symref.ref);
507 		if (ret->ref.symref.ref == NULL) {
508 			free(ret->ref.symref.name);
509 			free(ret);
510 			return NULL;
511 		}
512 	} else {
513 		ret->ref.ref.name = strdup(ref->ref.ref.name);
514 		if (ret->ref.ref.name == NULL) {
515 			free(ret);
516 			return NULL;
517 		}
518 		memcpy(&ret->ref.ref.id, &ref->ref.ref.id,
519 		    sizeof(ret->ref.ref.id));
520 	}
521 
522 	return ret;
523 }
524 
525 const struct got_error *
526 got_reflist_entry_dup(struct got_reflist_entry **newp,
527     struct got_reflist_entry *re)
528 {
529 	const struct got_error *err = NULL;
530 	struct got_reflist_entry *new;
531 
532 	*newp = NULL;
533 
534 	new = malloc(sizeof(*new));
535 	if (new == NULL)
536 		return got_error_from_errno("malloc");
537 
538 	new->ref = got_ref_dup(re->ref);
539 	if (new->ref == NULL) {
540 		err = got_error_from_errno("got_ref_dup");
541 		free(new);
542 		return err;
543 	}
544 
545 	*newp = new;
546 	return NULL;
547 }
548 
549 const struct got_error *
550 got_ref_resolve_symbolic(struct got_reference **resolved,
551     struct got_repository *repo, struct got_reference *ref)
552 {
553 	struct got_reference *nextref;
554 	const struct got_error *err;
555 
556 	err = got_ref_open(&nextref, repo, ref->ref.symref.ref, 0);
557 	if (err)
558 		return err;
559 
560 	if (nextref->flags & GOT_REF_IS_SYMBOLIC)
561 		err = got_ref_resolve_symbolic(resolved, repo, nextref);
562 	else
563 		*resolved = got_ref_dup(nextref);
564 
565 	got_ref_close(nextref);
566 	return err;
567 }
568 
569 static const struct got_error *
570 ref_resolve(struct got_object_id **id, struct got_repository *repo,
571     struct got_reference *ref, int recursion)
572 {
573 	const struct got_error *err;
574 
575 	if (recursion <= 0)
576 		return got_error_msg(GOT_ERR_RECURSION,
577 		    "reference recursion limit reached");
578 
579 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
580 		struct got_reference *resolved = NULL;
581 		err = got_ref_resolve_symbolic(&resolved, repo, ref);
582 		if (err == NULL)
583 			err = ref_resolve(id, repo, resolved, --recursion);
584 		if (resolved)
585 			got_ref_close(resolved);
586 		return err;
587 	}
588 
589 	*id = calloc(1, sizeof(**id));
590 	if (*id == NULL)
591 		return got_error_from_errno("calloc");
592 	memcpy(*id, &ref->ref.ref.id, sizeof(**id));
593 	return NULL;
594 }
595 
596 const struct got_error *
597 got_ref_resolve(struct got_object_id **id, struct got_repository *repo,
598     struct got_reference *ref)
599 {
600 	return ref_resolve(id, repo, ref, GOT_REF_RECURSE_MAX);
601 }
602 
603 char *
604 got_ref_to_str(struct got_reference *ref)
605 {
606 	char *str;
607 
608 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
609 		return strdup(ref->ref.symref.ref);
610 
611 	if (got_object_id_str(&str, &ref->ref.ref.id) != NULL)
612 		return NULL;
613 
614 	return str;
615 }
616 
617 const char *
618 got_ref_get_name(struct got_reference *ref)
619 {
620 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
621 		return ref->ref.symref.name;
622 
623 	return ref->ref.ref.name;
624 }
625 
626 const char *
627 got_ref_get_symref_target(struct got_reference *ref)
628 {
629 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
630 		return ref->ref.symref.ref;
631 
632 	return NULL;
633 }
634 
635 time_t
636 got_ref_get_mtime(struct got_reference *ref)
637 {
638 	return ref->mtime;
639 }
640 
641 const struct got_error *
642 got_ref_cmp_by_name(void *arg, int *cmp, struct got_reference *re1,
643     struct got_reference* re2)
644 {
645 	const char *name1 = got_ref_get_name(re1);
646 	const char *name2 = got_ref_get_name(re2);
647 
648 	*cmp = got_path_cmp(name1, name2, strlen(name1), strlen(name2));
649 	return NULL;
650 }
651 
652 const struct got_error *
653 got_ref_cmp_tags(void *arg, int *cmp, struct got_reference *ref1,
654     struct got_reference *ref2)
655 {
656 	const struct got_error *err = NULL;
657 	struct got_repository *repo = arg;
658 	struct got_object_id *id1, *id2 = NULL;
659 	struct got_tag_object *tag1 = NULL, *tag2 = NULL;
660 	struct got_commit_object *commit1 = NULL, *commit2 = NULL;
661 	time_t time1, time2;
662 
663 	*cmp = 0;
664 
665 	err = got_ref_resolve(&id1, repo, ref1);
666 	if (err)
667 		return err;
668 	err = got_object_open_as_tag(&tag1, repo, id1);
669 	if (err) {
670 		if (err->code != GOT_ERR_OBJ_TYPE)
671 			goto done;
672 		/* "lightweight" tag */
673 		err = got_object_open_as_commit(&commit1, repo, id1);
674 		if (err)
675 			goto done;
676 		time1 = got_object_commit_get_committer_time(commit1);
677 	} else
678 		time1 = got_object_tag_get_tagger_time(tag1);
679 
680 	err = got_ref_resolve(&id2, repo, ref2);
681 	if (err)
682 		goto done;
683 	err = got_object_open_as_tag(&tag2, repo, id2);
684 	if (err) {
685 		if (err->code != GOT_ERR_OBJ_TYPE)
686 			goto done;
687 		/* "lightweight" tag */
688 		err = got_object_open_as_commit(&commit2, repo, id2);
689 		if (err)
690 			goto done;
691 		time2 = got_object_commit_get_committer_time(commit2);
692 	} else
693 		time2 = got_object_tag_get_tagger_time(tag2);
694 
695 	/* Put latest tags first. */
696 	if (time1 < time2)
697 		*cmp = 1;
698 	else if (time1 > time2)
699 		*cmp = -1;
700 	else
701 		err = got_ref_cmp_by_name(NULL, cmp, ref2, ref1);
702 done:
703 	free(id1);
704 	free(id2);
705 	if (tag1)
706 		got_object_tag_close(tag1);
707 	if (tag2)
708 		got_object_tag_close(tag2);
709 	if (commit1)
710 		got_object_commit_close(commit1);
711 	if (commit2)
712 		got_object_commit_close(commit2);
713 	return err;
714 }
715 
716 static const struct got_error *
717 get_committer_time(struct got_reference *ref, struct got_repository *repo)
718 {
719 	const struct got_error *err = NULL;
720 	int obj_type;
721 	struct got_commit_object *commit = NULL;
722 	struct got_tag_object *tag = NULL;
723 	struct got_object_id *id = NULL;
724 
725 	err = got_ref_resolve(&id, repo, ref);
726 	if (err)
727 		return err;
728 
729 	err = got_object_get_type(&obj_type, repo, id);
730 	if (err)
731 		goto done;
732 
733 	switch (obj_type) {
734 	case GOT_OBJ_TYPE_COMMIT:
735 		err = got_object_open_as_commit(&commit, repo, id);
736 		if (err)
737 			goto done;
738 		ref->committer_time =
739 		    got_object_commit_get_committer_time(commit);
740 		break;
741 	case GOT_OBJ_TYPE_TAG:
742 		err = got_object_open_as_tag(&tag, repo, id);
743 		if (err)
744 			goto done;
745 		ref->committer_time = got_object_tag_get_tagger_time(tag);
746 		break;
747 	default:
748 		/* best effort for other object types */
749 		ref->committer_time = got_ref_get_mtime(ref);
750 		break;
751 	}
752 done:
753 	free(id);
754 	if (commit)
755 		got_object_commit_close(commit);
756 	if (tag)
757 		got_object_tag_close(tag);
758 	return err;
759 }
760 
761 const struct got_error *
762 got_ref_cmp_by_commit_timestamp_descending(void *arg, int *cmp,
763     struct got_reference *ref1, struct got_reference *ref2)
764 {
765 	const struct got_error *err = NULL;
766 	struct got_repository *repo = arg;
767 
768 	*cmp = 0;
769 
770 	if (ref1->committer_time == 0) {
771 		err = get_committer_time(ref1, repo);
772 		if (err)
773 			return err;
774 	}
775 	if (ref2->committer_time == 0) {
776 		err = get_committer_time(ref2, repo);
777 		if (err)
778 			return err;
779 	}
780 
781 	if (ref1->committer_time < ref2->committer_time)
782 		*cmp = 1;
783 	else if (ref2->committer_time < ref1->committer_time)
784 		*cmp = -1;
785 	else
786 		return got_ref_cmp_by_name(arg, cmp, ref1, ref2);
787 
788 	return err;
789 }
790 
791 const struct got_error *
792 got_reflist_insert(struct got_reflist_entry **newp,
793     struct got_reflist_head *refs, struct got_reference *ref,
794     got_ref_cmp_cb cmp_cb, void *cmp_arg)
795 {
796 	const struct got_error *err;
797 	struct got_reflist_entry *new, *re;
798 	int cmp;
799 
800 	*newp = NULL;
801 
802 	if (cmp_cb != got_ref_cmp_by_name && (ref->flags & GOT_REF_IS_PACKED)) {
803 		/*
804 		 * If we are not sorting elements by name then we must still
805 		 * detect collisions between a packed ref and an on-disk ref
806 		 * using the same name. On-disk refs take precedence and are
807 		 * already present on the list before packed refs get added.
808 		 */
809 		TAILQ_FOREACH(re, refs, entry) {
810 			err = got_ref_cmp_by_name(NULL, &cmp, re->ref, ref);
811 			if (err)
812 				return err;
813 			if (cmp == 0)
814 				return NULL;
815 		}
816 	}
817 
818 	new = malloc(sizeof(*new));
819 	if (new == NULL)
820 		return got_error_from_errno("malloc");
821 	new->ref = ref;
822 	*newp = new;
823 
824 	/*
825 	 * We must de-duplicate entries on insert because packed-refs may
826 	 * contain redundant entries. On-disk refs take precedence.
827 	 * This code assumes that on-disk revs are read before packed-refs.
828 	 * We're iterating the list anyway, so insert elements sorted by name.
829 	 *
830 	 * Many callers will provide paths in a somewhat sorted order.
831 	 * Iterating backwards from the tail of the list should be more
832 	 * efficient than traversing through the entire list each time
833 	 * an element is inserted.
834 	 */
835 	re = TAILQ_LAST(refs, got_reflist_head);
836 	while (re) {
837 		err = (*cmp_cb)(cmp_arg, &cmp, re->ref, new->ref);
838 		if (err)
839 			return err;
840 		if (cmp == 0) {
841 			/* duplicate */
842 			free(new);
843 			*newp = NULL;
844 			return NULL;
845 		} else if (cmp < 0) {
846 			TAILQ_INSERT_AFTER(refs, re, new, entry);
847 			return NULL;
848 		}
849 		re = TAILQ_PREV(re, got_reflist_head, entry);
850 	}
851 
852 	TAILQ_INSERT_HEAD(refs, new, entry);
853 	return NULL;
854 }
855 
856 const struct got_error *
857 got_reflist_sort(struct got_reflist_head *refs,
858     got_ref_cmp_cb cmp_cb, void *cmp_arg)
859 {
860 	const struct got_error *err = NULL;
861 	struct got_reflist_entry *re, *tmp, *new;
862 	struct got_reflist_head sorted;
863 
864 	TAILQ_INIT(&sorted);
865 
866 	TAILQ_FOREACH_SAFE(re, refs, entry, tmp) {
867 		struct got_reference *ref = re->ref;
868 		TAILQ_REMOVE(refs, re, entry);
869 		free(re);
870 		err = got_reflist_insert(&new, &sorted, ref, cmp_cb, cmp_arg);
871 		if (err || new == NULL /* duplicate */)
872 			got_ref_close(ref);
873 		if (err)
874 			return err;
875 	}
876 
877 	TAILQ_CONCAT(refs, &sorted, entry);
878 	return NULL;
879 }
880 
881 static const struct got_error *
882 gather_on_disk_refs(struct got_reflist_head *refs, const char *path_refs,
883     const char *subdir, struct got_repository *repo,
884     got_ref_cmp_cb cmp_cb, void *cmp_arg)
885 {
886 	const struct got_error *err = NULL;
887 	DIR *d = NULL;
888 	char *path_subdir;
889 
890 	while (subdir[0] == '/')
891 		subdir++;
892 
893 	if (asprintf(&path_subdir, "%s/%s", path_refs, subdir) == -1)
894 		return got_error_from_errno("asprintf");
895 
896 	d = opendir(path_subdir);
897 	if (d == NULL)
898 		goto done;
899 
900 	for (;;) {
901 		struct dirent *dent;
902 		struct got_reference *ref;
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)
923 				goto done;
924 			if (ref) {
925 				struct got_reflist_entry *new;
926 				err = got_reflist_insert(&new, refs, ref,
927 				    cmp_cb, cmp_arg);
928 				if (err || new == NULL /* duplicate */)
929 					got_ref_close(ref);
930 				if (err)
931 					goto done;
932 			}
933 			break;
934 		case DT_DIR:
935 			if (asprintf(&child, "%s%s%s", subdir,
936 			    subdir[0] == '\0' ? "" : "/", dent->d_name) == -1) {
937 				err = got_error_from_errno("asprintf");
938 				break;
939 			}
940 			err = gather_on_disk_refs(refs, path_refs, child, repo,
941 			    cmp_cb, cmp_arg);
942 			free(child);
943 			break;
944 		default:
945 			break;
946 		}
947 	}
948 done:
949 	if (d)
950 		closedir(d);
951 	free(path_subdir);
952 	return err;
953 }
954 
955 const struct got_error *
956 got_ref_list(struct got_reflist_head *refs, struct got_repository *repo,
957     const char *ref_namespace, got_ref_cmp_cb cmp_cb, void *cmp_arg)
958 {
959 	const struct got_error *err;
960 	char *packed_refs_path = NULL, *path_refs = NULL;
961 	char *abs_namespace = NULL, *buf = NULL;
962 	const char *ondisk_ref_namespace = NULL;
963 	char *line = NULL;
964 	FILE *f = NULL;
965 	struct got_reference *ref;
966 	struct got_reflist_entry *new;
967 
968 	if (ref_namespace == NULL || ref_namespace[0] == '\0') {
969 		path_refs = get_refs_dir_path(repo, GOT_REF_HEAD);
970 		if (path_refs == NULL) {
971 			err = got_error_from_errno("get_refs_dir_path");
972 			goto done;
973 		}
974 		err = open_ref(&ref, path_refs, "", GOT_REF_HEAD, 0,
975 		    got_repo_get_object_format(repo));
976 		if (err)
977 			goto done;
978 		err = got_reflist_insert(&new, refs, ref, cmp_cb, cmp_arg);
979 		if (err || new == NULL /* duplicate */)
980 			got_ref_close(ref);
981 		if (err && err->code != GOT_ERR_NOT_REF)
982 			goto done;
983 	} else {
984 		/* Try listing a single reference. */
985 		const char *refname = ref_namespace;
986 		path_refs = get_refs_dir_path(repo, refname);
987 		if (path_refs == NULL) {
988 			err = got_error_from_errno("get_refs_dir_path");
989 			goto done;
990 		}
991 		err = open_ref(&ref, path_refs, "", refname, 0,
992 		    got_repo_get_object_format(repo));
993 		if (err) {
994 			if (err->code != GOT_ERR_NOT_REF)
995 				goto done;
996 			/* Try to look up references in a given namespace. */
997 		} else {
998 			err = got_reflist_insert(&new, refs, ref,
999 			    cmp_cb, cmp_arg);
1000 			if (err || new == NULL /* duplicate */)
1001 				got_ref_close(ref);
1002 			return err;
1003 		}
1004 	}
1005 
1006 	if (ref_namespace) {
1007 		size_t len;
1008 		/* Canonicalize the path to eliminate double-slashes if any. */
1009 		if (asprintf(&abs_namespace, "/%s", ref_namespace) == -1) {
1010 			err = got_error_from_errno("asprintf");
1011 			goto done;
1012 		}
1013 		len = strlen(abs_namespace) + 1;
1014 		buf = malloc(len);
1015 		if (buf == NULL) {
1016 			err = got_error_from_errno("malloc");
1017 			goto done;
1018 		}
1019 		err = got_canonpath(abs_namespace, buf, len);
1020 		if (err)
1021 			goto done;
1022 		ondisk_ref_namespace = buf;
1023 		while (ondisk_ref_namespace[0] == '/')
1024 			ondisk_ref_namespace++;
1025 		if (strncmp(ondisk_ref_namespace, "refs/", 5) == 0)
1026 			ondisk_ref_namespace += 5;
1027 		else if (strcmp(ondisk_ref_namespace, "refs") == 0)
1028 			ondisk_ref_namespace = "";
1029 	}
1030 
1031 	/* Gather on-disk refs before parsing packed-refs. */
1032 	free(path_refs);
1033 	path_refs = get_refs_dir_path(repo, "");
1034 	if (path_refs == NULL) {
1035 		err = got_error_from_errno("get_refs_dir_path");
1036 		goto done;
1037 	}
1038 	err = gather_on_disk_refs(refs, path_refs,
1039 	    ondisk_ref_namespace ? ondisk_ref_namespace : "", repo,
1040 	    cmp_cb, cmp_arg);
1041 	if (err)
1042 		goto done;
1043 
1044 	/*
1045 	 * The packed-refs file may contain redundant entries, in which
1046 	 * case on-disk refs take precedence.
1047 	 */
1048 	packed_refs_path = got_repo_get_path_packed_refs(repo);
1049 	if (packed_refs_path == NULL) {
1050 		err = got_error_from_errno("got_repo_get_path_packed_refs");
1051 		goto done;
1052 	}
1053 
1054 	f = fopen(packed_refs_path, "re");
1055 	if (f) {
1056 		size_t linesize = 0;
1057 		ssize_t linelen;
1058 		struct stat sb;
1059 
1060 		if (fstat(fileno(f), &sb) == -1) {
1061 			err = got_error_from_errno2("fstat", packed_refs_path);
1062 			goto done;
1063 		}
1064 		for (;;) {
1065 			linelen = getline(&line, &linesize, f);
1066 			if (linelen == -1) {
1067 				if (feof(f))
1068 					break;
1069 				err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
1070 				goto done;
1071 			}
1072 			if (linelen > 0 && line[linelen - 1] == '\n')
1073 				line[linelen - 1] = '\0';
1074 			err = parse_packed_ref_line(&ref, NULL, line,
1075 			    sb.st_mtime, got_repo_get_object_format(repo));
1076 			if (err)
1077 				goto done;
1078 			if (ref) {
1079 				if (ref_namespace) {
1080 					const char *name;
1081 					name = got_ref_get_name(ref);
1082 					if (!got_path_is_child(name,
1083 					    ref_namespace,
1084 					    strlen(ref_namespace))) {
1085 						got_ref_close(ref);
1086 						continue;
1087 					}
1088 				}
1089 				err = got_reflist_insert(&new, refs, ref,
1090 				    cmp_cb, cmp_arg);
1091 				if (err || new == NULL /* duplicate */)
1092 					got_ref_close(ref);
1093 				if (err)
1094 					goto done;
1095 			}
1096 		}
1097 	}
1098 done:
1099 	free(packed_refs_path);
1100 	free(abs_namespace);
1101 	free(buf);
1102 	free(line);
1103 	free(path_refs);
1104 	if (f && fclose(f) == EOF && err == NULL)
1105 		err = got_error_from_errno("fclose");
1106 	return err;
1107 }
1108 
1109 void
1110 got_ref_list_free(struct got_reflist_head *refs)
1111 {
1112 	struct got_reflist_entry *re;
1113 
1114 	while ((re = TAILQ_FIRST(refs))) {
1115 		TAILQ_REMOVE(refs, re, entry);
1116 		got_ref_close(re->ref);
1117 		free(re);
1118 	}
1119 }
1120 
1121 int
1122 got_ref_is_symbolic(struct got_reference *ref)
1123 {
1124 	return (ref->flags & GOT_REF_IS_SYMBOLIC);
1125 }
1126 
1127 const struct got_error *
1128 got_ref_change_ref(struct got_reference *ref, struct got_object_id *id)
1129 {
1130 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
1131 		return got_error(GOT_ERR_BAD_REF_TYPE);
1132 
1133 	memcpy(&ref->ref.ref.id, id, sizeof(ref->ref.ref.id));
1134 	return NULL;
1135 }
1136 
1137 const struct got_error *
1138 got_ref_change_symref(struct got_reference *ref, const char *refname)
1139 {
1140 	char *new_name;
1141 
1142 	if ((ref->flags & GOT_REF_IS_SYMBOLIC) == 0)
1143 		return got_error(GOT_ERR_BAD_REF_TYPE);
1144 
1145 	new_name = strdup(refname);
1146 	if (new_name == NULL)
1147 		return got_error_from_errno("strdup");
1148 
1149 	free(ref->ref.symref.ref);
1150 	ref->ref.symref.ref = new_name;
1151 	return NULL;
1152 }
1153 
1154 const struct got_error *
1155 got_ref_change_symref_to_ref(struct got_reference *symref,
1156     struct got_object_id *id)
1157 {
1158 	if ((symref->flags & GOT_REF_IS_SYMBOLIC) == 0)
1159 		return got_error(GOT_ERR_BAD_REF_TYPE);
1160 
1161 	symref->ref.ref.name = symref->ref.symref.name;
1162 	memcpy(&symref->ref.ref.id, id, sizeof(symref->ref.ref.id));
1163 	symref->flags &= ~GOT_REF_IS_SYMBOLIC;
1164 	return NULL;
1165 }
1166 
1167 const struct got_error *
1168 got_ref_write(struct got_reference *ref, struct got_repository *repo)
1169 {
1170 	const struct got_error *err = NULL, *unlock_err = NULL;
1171 	const char *name = got_ref_get_name(ref);
1172 	char *path_refs = NULL, *path = NULL, *tmppath = NULL;
1173 	struct got_lockfile *lf = NULL;
1174 	FILE *f = NULL;
1175 	size_t n;
1176 	struct stat sb;
1177 
1178 	path_refs = get_refs_dir_path(repo, name);
1179 	if (path_refs == NULL) {
1180 		err = got_error_from_errno2("get_refs_dir_path", name);
1181 		goto done;
1182 	}
1183 
1184 	if (asprintf(&path, "%s/%s", path_refs, name) == -1) {
1185 		err = got_error_from_errno("asprintf");
1186 		goto done;
1187 	}
1188 
1189 	err = got_opentemp_named(&tmppath, &f, path, "");
1190 	if (err) {
1191 		char *parent;
1192 		if (!(err->code == GOT_ERR_ERRNO && errno == ENOENT))
1193 			goto done;
1194 		err = got_path_dirname(&parent, path);
1195 		if (err)
1196 			goto done;
1197 		err = got_path_mkdir(parent);
1198 		free(parent);
1199 		if (err)
1200 			goto done;
1201 		err = got_opentemp_named(&tmppath, &f, path, "");
1202 		if (err)
1203 			goto done;
1204 	}
1205 
1206 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
1207 		n = fprintf(f, "ref: %s\n", ref->ref.symref.ref);
1208 		if (n != strlen(ref->ref.symref.ref) + 6) {
1209 			err = got_ferror(f, GOT_ERR_IO);
1210 			goto done;
1211 		}
1212 	} else {
1213 		char *hex;
1214 		size_t len;
1215 
1216 		err = got_object_id_str(&hex, &ref->ref.ref.id);
1217 		if (err)
1218 			goto done;
1219 		len = strlen(hex);
1220 		n = fprintf(f, "%s\n", hex);
1221 		free(hex);
1222 		if (n != len + 1) {
1223 			err = got_ferror(f, GOT_ERR_IO);
1224 			goto done;
1225 		}
1226 	}
1227 
1228 	if (ref->lf == NULL) {
1229 		err = got_lockfile_lock(&lf, path, -1);
1230 		if (err)
1231 			goto done;
1232 	}
1233 
1234 	/* XXX: check if old content matches our expectations? */
1235 
1236 	if (stat(path, &sb) != 0) {
1237 		if (errno != ENOENT) {
1238 			err = got_error_from_errno2("stat", path);
1239 			goto done;
1240 		}
1241 		sb.st_mode = GOT_DEFAULT_FILE_MODE;
1242 	}
1243 
1244 	if (fchmod(fileno(f), sb.st_mode) != 0) {
1245 		err = got_error_from_errno2("fchmod", tmppath);
1246 		goto done;
1247 	}
1248 
1249 	if (rename(tmppath, path) != 0) {
1250 		err = got_error_from_errno3("rename", tmppath, path);
1251 		goto done;
1252 	}
1253 	free(tmppath);
1254 	tmppath = NULL;
1255 
1256 	if (stat(path, &sb) == -1) {
1257 		err = got_error_from_errno2("stat", path);
1258 		goto done;
1259 	}
1260 	ref->mtime = sb.st_mtime;
1261 done:
1262 	if (ref->lf == NULL && lf)
1263 		unlock_err = got_lockfile_unlock(lf, -1);
1264 	if (f) {
1265 		if (fclose(f) == EOF && err == NULL)
1266 			err = got_error_from_errno("fclose");
1267 	}
1268 	free(path_refs);
1269 	free(path);
1270 	if (tmppath) {
1271 		if (unlink(tmppath) == -1 && err == NULL)
1272 			err = got_error_from_errno2("unlink", tmppath);
1273 		free(tmppath);
1274 	}
1275 	return err ? err : unlock_err;
1276 }
1277 
1278 static const struct got_error *
1279 delete_packed_ref(struct got_reference *delref, struct got_repository *repo)
1280 {
1281 	const struct got_error *err = NULL, *unlock_err = NULL;
1282 	struct got_lockfile *lf = NULL;
1283 	FILE *f = NULL, *tmpf = NULL;
1284 	char *line = NULL, *packed_refs_path, *tmppath = NULL;
1285 	size_t linesize = 0;
1286 	struct got_reflist_head refs;
1287 	int found_delref = 0;
1288 
1289 	/* The packed-refs file does not cotain symbolic references. */
1290 	if (delref->flags & GOT_REF_IS_SYMBOLIC)
1291 		return got_error(GOT_ERR_BAD_REF_DATA);
1292 
1293 	TAILQ_INIT(&refs);
1294 
1295 	packed_refs_path = got_repo_get_path_packed_refs(repo);
1296 	if (packed_refs_path == NULL)
1297 		return got_error_from_errno("got_repo_get_path_packed_refs");
1298 
1299 	err = got_opentemp_named(&tmppath, &tmpf, packed_refs_path, "");
1300 	if (err)
1301 		goto done;
1302 
1303 	if (delref->lf == NULL) {
1304 		err = got_lockfile_lock(&lf, packed_refs_path, -1);
1305 		if (err)
1306 			goto done;
1307 	}
1308 
1309 	f = fopen(packed_refs_path, "re");
1310 	if (f == NULL) {
1311 		err = got_error_from_errno2("fopen", packed_refs_path);
1312 		goto done;
1313 	}
1314 	for (;;) {
1315 		ssize_t linelen;
1316 		struct got_reference *ref;
1317 		struct got_reflist_entry *new;
1318 
1319 		linelen = getline(&line, &linesize, f);
1320 		if (linelen == -1) {
1321 			if (feof(f))
1322 				break;
1323 			err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
1324 			goto done;
1325 		}
1326 		if (linelen > 0 && line[linelen - 1] == '\n')
1327 			line[linelen - 1] = '\0';
1328 		err = parse_packed_ref_line(&ref, NULL, line, 0,
1329 		    got_repo_get_object_format(repo));
1330 		if (err)
1331 			goto done;
1332 		if (ref == NULL)
1333 			continue;
1334 
1335 		if (strcmp(ref->ref.ref.name, delref->ref.ref.name) == 0 &&
1336 		    got_object_id_cmp(&ref->ref.ref.id,
1337 		    &delref->ref.ref.id) == 0) {
1338 			found_delref = 1;
1339 			got_ref_close(ref);
1340 			continue;
1341 		}
1342 
1343 		err = got_reflist_insert(&new, &refs, ref,
1344 		    got_ref_cmp_by_name, NULL);
1345 		if (err || new == NULL /* duplicate */)
1346 			got_ref_close(ref);
1347 		if (err)
1348 			goto done;
1349 	}
1350 
1351 	if (found_delref) {
1352 		struct got_reflist_entry *re;
1353 		size_t n;
1354 		struct stat sb;
1355 
1356 		n = fprintf(tmpf, "%s\n", GOT_PACKED_REFS_HEADER);
1357 		if (n != sizeof(GOT_PACKED_REFS_HEADER)) {
1358 			err = got_ferror(f, GOT_ERR_IO);
1359 			goto done;
1360 		}
1361 
1362 		TAILQ_FOREACH(re, &refs, entry) {
1363 			char *hex;
1364 			size_t len;
1365 
1366 			err = got_object_id_str(&hex, &re->ref->ref.ref.id);
1367 			if (err)
1368 				goto done;
1369 			len = strlen(hex);
1370 			n = fprintf(tmpf, "%s ", hex);
1371 			free(hex);
1372 			if (n != len + 1) {
1373 				err = got_ferror(f, GOT_ERR_IO);
1374 				goto done;
1375 			}
1376 
1377 			n = fprintf(tmpf, "%s\n", re->ref->ref.ref.name);
1378 			if (n != strlen(re->ref->ref.ref.name) + 1) {
1379 				err = got_ferror(f, GOT_ERR_IO);
1380 				goto done;
1381 			}
1382 		}
1383 
1384 		if (fflush(tmpf) != 0) {
1385 			err = got_error_from_errno("fflush");
1386 			goto done;
1387 		}
1388 
1389 		if (fstat(fileno(f), &sb) != 0) {
1390 			if (errno != ENOENT) {
1391 				err = got_error_from_errno2("fstat",
1392 				    packed_refs_path);
1393 				goto done;
1394 			}
1395 			sb.st_mode = GOT_DEFAULT_FILE_MODE;
1396 		}
1397 
1398 		if (fchmod(fileno(tmpf), sb.st_mode) != 0) {
1399 			err = got_error_from_errno2("fchmod", tmppath);
1400 			goto done;
1401 		}
1402 
1403 		if (rename(tmppath, packed_refs_path) != 0) {
1404 			err = got_error_from_errno3("rename", tmppath,
1405 			    packed_refs_path);
1406 			goto done;
1407 		}
1408 		free(tmppath);
1409 		tmppath = NULL;
1410 	}
1411 done:
1412 	if (delref->lf == NULL && lf)
1413 		unlock_err = got_lockfile_unlock(lf, -1);
1414 	if (f) {
1415 		if (fclose(f) == EOF && err == NULL)
1416 			err = got_error_from_errno("fclose");
1417 	}
1418 	if (tmppath && unlink(tmppath) == -1 && err == NULL)
1419 		err = got_error_from_errno2("unlink", tmppath);
1420 	if (tmpf && fclose(tmpf) == EOF && err == NULL)
1421 		err = got_error_from_errno("fclose");
1422 	free(tmppath);
1423 	free(packed_refs_path);
1424 	free(line);
1425 	got_ref_list_free(&refs);
1426 	return err ? err : unlock_err;
1427 }
1428 
1429 static const struct got_error *
1430 delete_loose_ref(struct got_reference *ref, struct got_repository *repo)
1431 {
1432 	const struct got_error *err = NULL, *unlock_err = NULL;
1433 	const char *name = got_ref_get_name(ref);
1434 	char *path_refs = NULL, *path = NULL;
1435 	struct got_lockfile *lf = NULL;
1436 
1437 	path_refs = get_refs_dir_path(repo, name);
1438 	if (path_refs == NULL) {
1439 		err = got_error_from_errno2("get_refs_dir_path", name);
1440 		goto done;
1441 	}
1442 
1443 	if (asprintf(&path, "%s/%s", path_refs, name) == -1) {
1444 		err = got_error_from_errno("asprintf");
1445 		goto done;
1446 	}
1447 
1448 	if (ref->lf == NULL) {
1449 		err = got_lockfile_lock(&lf, path, -1);
1450 		if (err)
1451 			goto done;
1452 	}
1453 
1454 	/* XXX: check if old content matches our expectations? */
1455 
1456 	if (unlink(path) == -1)
1457 		err = got_error_from_errno2("unlink", path);
1458 done:
1459 	if (ref->lf == NULL && lf)
1460 		unlock_err = got_lockfile_unlock(lf, -1);
1461 
1462 	free(path_refs);
1463 	free(path);
1464 	return err ? err : unlock_err;
1465 }
1466 
1467 const struct got_error *
1468 got_ref_delete(struct got_reference *ref, struct got_repository *repo)
1469 {
1470 	const struct got_error *err = NULL;
1471 	struct got_reference *ref2;
1472 
1473 	if (ref->flags & GOT_REF_IS_PACKED) {
1474 		err = delete_packed_ref(ref, repo);
1475 		if (err)
1476 			return err;
1477 
1478 		err = got_ref_open(&ref2, repo, got_ref_get_name(ref), 0);
1479 		if (err) {
1480 			if (err->code == GOT_ERR_NOT_REF)
1481 				return NULL;
1482 			return err;
1483 		}
1484 
1485 		err = delete_loose_ref(ref2, repo);
1486 		got_ref_close(ref2);
1487 		return err;
1488 	} else {
1489 		err = delete_loose_ref(ref, repo);
1490 		if (err)
1491 			return err;
1492 
1493 		err = got_ref_open(&ref2, repo, got_ref_get_name(ref), 0);
1494 		if (err) {
1495 			if (err->code == GOT_ERR_NOT_REF)
1496 				return NULL;
1497 			return err;
1498 		}
1499 
1500 		err = delete_packed_ref(ref2, repo);
1501 		got_ref_close(ref2);
1502 		return err;
1503 	}
1504 }
1505 
1506 const struct got_error *
1507 got_ref_unlock(struct got_reference *ref)
1508 {
1509 	const struct got_error *err;
1510 	err = got_lockfile_unlock(ref->lf, -1);
1511 	ref->lf = NULL;
1512 	return err;
1513 }
1514 
1515 struct got_reflist_object_id_map {
1516 	struct got_object_idset *idset;
1517 };
1518 
1519 struct got_reflist_object_id_map_entry {
1520 	struct got_reflist_head refs;
1521 };
1522 
1523 static const struct got_error *
1524 add_object_id_map_entry(struct got_object_idset *idset,
1525     struct got_object_id *id, struct got_reflist_entry *re)
1526 {
1527 	const struct got_error *err = NULL;
1528 	struct got_reflist_object_id_map_entry *ent;
1529 	struct got_reflist_entry *new;
1530 
1531 	ent = got_object_idset_get(idset, id);
1532 	if (ent == NULL) {
1533 		ent = malloc(sizeof(*ent));
1534 		if (ent == NULL)
1535 			return got_error_from_errno("malloc");
1536 
1537 		TAILQ_INIT(&ent->refs);
1538 		err = got_object_idset_add(idset, id, ent);
1539 		if (err) {
1540 			free(ent);
1541 			return err;
1542 		}
1543 	}
1544 
1545 	err = got_reflist_entry_dup(&new, re);
1546 	if (err)
1547 		return err;
1548 
1549 	TAILQ_INSERT_TAIL(&ent->refs, new, entry);
1550 	return NULL;
1551 }
1552 
1553 const struct got_error *
1554 got_reflist_object_id_map_create(struct got_reflist_object_id_map **map,
1555     struct got_reflist_head *refs, struct got_repository *repo)
1556 {
1557 	const struct got_error *err = NULL;
1558 	struct got_object_idset *idset;
1559 	struct got_object_id *id = NULL;
1560 	struct got_reflist_entry *re;
1561 
1562 	idset = got_object_idset_alloc();
1563 	if (idset == NULL)
1564 		return got_error_from_errno("got_object_idset_alloc");
1565 
1566 	*map = malloc(sizeof(**map));
1567 	if (*map == NULL) {
1568 		got_object_idset_free(idset);
1569 		return got_error_from_errno("malloc");
1570 	}
1571 	(*map)->idset = idset;
1572 
1573 	TAILQ_FOREACH(re, refs, entry) {
1574 		struct got_tag_object *tag = NULL;
1575 
1576 		err = got_ref_resolve(&id, repo, re->ref);
1577 		if (err)
1578 			goto done;
1579 
1580 		err = add_object_id_map_entry(idset, id, re);
1581 		if (err)
1582 			goto done;
1583 
1584 		if (strstr(got_ref_get_name(re->ref), "/tags/") == NULL) {
1585 			free(id);
1586 			id = NULL;
1587 			continue;
1588 		}
1589 
1590 		err = got_object_open_as_tag(&tag, repo, id);
1591 		if (err) {
1592 			if (err->code != GOT_ERR_OBJ_TYPE)
1593 				goto done;
1594 			/* Ref points at something other than a tag. */
1595 			err = NULL;
1596 			tag = NULL;
1597 			free(id);
1598 			id = NULL;
1599 			continue;
1600 		}
1601 
1602 		err = add_object_id_map_entry(idset,
1603 		    got_object_tag_get_object_id(tag), re);
1604 		got_object_tag_close(tag);
1605 		if (err)
1606 			goto done;
1607 
1608 		free(id);
1609 		id = NULL;
1610 	}
1611 done:
1612 	free(id);
1613 	if (err) {
1614 		got_reflist_object_id_map_free(*map);
1615 		*map = NULL;
1616 	}
1617 	return err;
1618 }
1619 
1620 struct got_reflist_head *
1621 got_reflist_object_id_map_lookup(struct got_reflist_object_id_map *map,
1622     struct got_object_id *id)
1623 {
1624 	struct got_reflist_object_id_map_entry *ent;
1625 	ent = got_object_idset_get(map->idset, id);
1626 	if (ent)
1627 		return &ent->refs;
1628 	return NULL;
1629 }
1630 
1631 static const struct got_error *
1632 free_id_map_entry(struct got_object_id *id, void *data, void *arg)
1633 {
1634 	struct got_reflist_object_id_map_entry *ent = data;
1635 
1636 	got_ref_list_free(&ent->refs);
1637 	free(ent);
1638 	return NULL;
1639 }
1640 
1641 void
1642 got_reflist_object_id_map_free(struct got_reflist_object_id_map *map)
1643 {
1644 	got_object_idset_for_each(map->idset, free_id_map_entry, NULL);
1645 	got_object_idset_free(map->idset);
1646 	free(map);
1647 }