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 <sys/types.h>
18 #include <sys/queue.h>
19 #include <sys/stat.h>
20 
21 #include <errno.h>
22 #include <dirent.h>
23 #include <limits.h>
24 #include <sha1.h>
25 #include <stdio.h>
26 #include <stdlib.h>
27 #include <string.h>
28 #include <unistd.h>
29 #include <util.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_sha1.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)
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_sha1_digest(id.sha1, line))
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 {
174 	const struct got_error *err = NULL;
175 	FILE *f;
176 	char *line = NULL;
177 	size_t linesize = 0;
178 	ssize_t linelen;
179 	struct got_lockfile *lf = NULL;
180 	struct stat sb;
181 
182 	if (lock) {
183 		err = got_lockfile_lock(&lf, abspath, -1);
184 		if (err) {
185 			if (err->code == GOT_ERR_ERRNO && errno == ENOENT)
186 				err = got_error_not_ref(name);
187 			return err;
188 		}
189 	}
190 
191 	f = fopen(abspath, "rbe");
192 	if (f == NULL) {
193 		if (errno != ENOTDIR && errno != ENOENT)
194 			err = got_error_from_errno2("fopen", abspath);
195 		else
196 			err = got_error_not_ref(name);
197 		if (lock)
198 			got_lockfile_unlock(lf, -1);
199 		return err;
200 	}
201 	if (fstat(fileno(f), &sb) == -1) {
202 		err = got_error_from_errno2("fstat", abspath);
203 		goto done;
204 	}
205 
206 	linelen = getline(&line, &linesize, f);
207 	if (linelen == -1) {
208 		if (feof(f))
209 			err = NULL; /* ignore empty files (could be locks) */
210 		else {
211 			if (errno == EISDIR)
212 				err = got_error(GOT_ERR_NOT_REF);
213 			else if (ferror(f))
214 				err = got_ferror(f, GOT_ERR_IO);
215 			else
216 				err = got_error_from_errno2("getline", abspath);
217 		}
218 		if (lock)
219 			got_lockfile_unlock(lf, -1);
220 		goto done;
221 	}
222 	while (linelen > 0 && line[linelen - 1] == '\n') {
223 		line[linelen - 1] = '\0';
224 		linelen--;
225 	}
226 
227 	err = parse_ref_line(ref, absname, line, sb.st_mtime);
228 	if (lock) {
229 		if (err)
230 			got_lockfile_unlock(lf, -1);
231 		else {
232 			if (*ref)
233 				(*ref)->lf = lf;
234 			else
235 				got_lockfile_unlock(lf, -1);
236 		}
237 	}
238 done:
239 	free(line);
240 	if (fclose(f) == EOF && err == NULL) {
241 		err = got_error_from_errno("fclose");
242 		if (*ref) {
243 			if (lock)
244 				got_ref_unlock(*ref);
245 			got_ref_close(*ref);
246 			*ref = NULL;
247 		}
248 	}
249 	return err;
250 }
251 
252 static int
253 is_well_known_ref(const char *refname)
254 {
255 	return (strcmp(refname, GOT_REF_HEAD) == 0 ||
256 	    strcmp(refname, GOT_REF_ORIG_HEAD) == 0 ||
257 	    strcmp(refname, GOT_REF_MERGE_HEAD) == 0 ||
258 	    strcmp(refname, GOT_REF_FETCH_HEAD) == 0);
259 }
260 
261 static char *
262 get_refs_dir_path(struct got_repository *repo, const char *refname)
263 {
264 	if (is_well_known_ref(refname) || strncmp(refname, "refs/", 5) == 0)
265 		return strdup(got_repo_get_path_git_dir(repo));
266 
267 	return got_repo_get_path_refs(repo);
268 }
269 
270 const struct got_error *
271 got_ref_alloc(struct got_reference **ref, const char *name,
272     struct got_object_id *id)
273 {
274 	if (!got_ref_name_is_valid(name))
275 		return got_error_path(name, GOT_ERR_BAD_REF_NAME);
276 
277 	return alloc_ref(ref, name, id, 0, 0);
278 }
279 
280 const struct got_error *
281 got_ref_alloc_symref(struct got_reference **ref, const char *name,
282 	struct got_reference *target_ref)
283 {
284 	if (!got_ref_name_is_valid(name))
285 		return got_error_path(name, GOT_ERR_BAD_REF_NAME);
286 
287 	return alloc_symref(ref, name, got_ref_get_name(target_ref), 0);
288 }
289 
290 static const struct got_error *
291 parse_packed_ref_line(struct got_reference **ref, const char *abs_refname,
292     const char *line, time_t mtime)
293 {
294 	struct got_object_id id;
295 	const char *name;
296 
297 	*ref = NULL;
298 
299 	if (line[0] == '#' || line[0] == '^')
300 		return NULL;
301 
302 	if (!got_parse_sha1_digest(id.sha1, line))
303 		return got_error(GOT_ERR_BAD_REF_DATA);
304 
305 	if (abs_refname) {
306 		if (strcmp(line + SHA1_DIGEST_STRING_LENGTH, abs_refname) != 0)
307 			return NULL;
308 		name = abs_refname;
309 	} else
310 		name = line + SHA1_DIGEST_STRING_LENGTH;
311 
312 	return alloc_ref(ref, name, &id, GOT_REF_IS_PACKED, mtime);
313 }
314 
315 static const struct got_error *
316 open_packed_ref(struct got_reference **ref, FILE *f, const char **subdirs,
317     int nsubdirs, const char *refname, time_t mtime)
318 {
319 	const struct got_error *err = NULL;
320 	char *abs_refname;
321 	char *line = NULL;
322 	size_t linesize = 0;
323 	ssize_t linelen;
324 	int i, ref_is_absolute = (strncmp(refname, "refs/", 5) == 0);
325 
326 	*ref = NULL;
327 
328 	if (ref_is_absolute)
329 		abs_refname = (char *)refname;
330 	do {
331 		linelen = getline(&line, &linesize, f);
332 		if (linelen == -1) {
333 			if (feof(f))
334 				break;
335 			err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
336 			break;
337 		}
338 		if (linelen > 0 && line[linelen - 1] == '\n')
339 			line[linelen - 1] = '\0';
340 		for (i = 0; i < nsubdirs; i++) {
341 			if (!ref_is_absolute &&
342 			    asprintf(&abs_refname, "refs/%s/%s", subdirs[i],
343 			    refname) == -1)
344 				return got_error_from_errno("asprintf");
345 			err = parse_packed_ref_line(ref, abs_refname, line,
346 			    mtime);
347 			if (!ref_is_absolute)
348 				free(abs_refname);
349 			if (err || *ref != NULL)
350 				break;
351 		}
352 		if (err)
353 			break;
354 	} while (*ref == NULL);
355 	free(line);
356 
357 	return err;
358 }
359 
360 static const struct got_error *
361 open_ref(struct got_reference **ref, const char *path_refs, const char *subdir,
362     const char *name, int lock)
363 {
364 	const struct got_error *err = NULL;
365 	char *path = NULL;
366 	char *absname = NULL;
367 	int ref_is_absolute = (strncmp(name, "refs/", 5) == 0);
368 	int ref_is_well_known = (subdir[0] == '\0' && is_well_known_ref(name));
369 
370 	*ref = NULL;
371 
372 	if (!got_ref_name_is_valid(name))
373 		return got_error_path(name, GOT_ERR_BAD_REF_NAME);
374 
375 	if (ref_is_absolute || ref_is_well_known) {
376 		if (asprintf(&path, "%s/%s", path_refs, name) == -1)
377 			return got_error_from_errno("asprintf");
378 		absname = (char *)name;
379 	} else {
380 		if (asprintf(&path, "%s/%s%s%s", path_refs, subdir,
381 		    subdir[0] ? "/" : "", name) == -1)
382 			return got_error_from_errno("asprintf");
383 
384 		if (asprintf(&absname, "refs/%s%s%s",
385 		    subdir, subdir[0] ? "/" : "", name) == -1) {
386 			err = got_error_from_errno("asprintf");
387 			goto done;
388 		}
389 	}
390 
391 	err = parse_ref_file(ref, name, absname, path, lock);
392 done:
393 	if (!ref_is_absolute && !ref_is_well_known)
394 		free(absname);
395 	free(path);
396 	return err;
397 }
398 
399 const struct got_error *
400 got_ref_open(struct got_reference **ref, struct got_repository *repo,
401     const char *refname, int lock)
402 {
403 	const struct got_error *err = NULL;
404 	char *packed_refs_path = NULL, *path_refs = NULL;
405 	const char *subdirs[] = {
406 	    GOT_REF_HEADS, GOT_REF_TAGS, GOT_REF_REMOTES
407 	};
408 	size_t i;
409 	int well_known = is_well_known_ref(refname);
410 	struct got_lockfile *lf = NULL;
411 
412 	*ref = NULL;
413 
414 	path_refs = get_refs_dir_path(repo, refname);
415 	if (path_refs == NULL) {
416 		err = got_error_from_errno2("get_refs_dir_path", refname);
417 		goto done;
418 	}
419 
420 	if (well_known) {
421 		err = open_ref(ref, path_refs, "", refname, lock);
422 	} else {
423 		FILE *f;
424 
425 		/* Search on-disk refs before packed refs! */
426 		for (i = 0; i < nitems(subdirs); i++) {
427 			err = open_ref(ref, path_refs, subdirs[i], refname,
428 			    lock);
429 			if ((err && err->code != GOT_ERR_NOT_REF) || *ref)
430 				goto done;
431 		}
432 
433 		packed_refs_path = got_repo_get_path_packed_refs(repo);
434 		if (packed_refs_path == NULL) {
435 			err = got_error_from_errno(
436 			    "got_repo_get_path_packed_refs");
437 			goto done;
438 		}
439 
440 		if (lock) {
441 			err = got_lockfile_lock(&lf, packed_refs_path, -1);
442 			if (err)
443 				goto done;
444 		}
445 		f = fopen(packed_refs_path, "rbe");
446 		if (f != NULL) {
447 			struct stat sb;
448 			if (fstat(fileno(f), &sb) == -1) {
449 				err = got_error_from_errno2("fstat",
450 				    packed_refs_path);
451 				goto done;
452 			}
453 			err = open_packed_ref(ref, f, subdirs, nitems(subdirs),
454 			    refname, sb.st_mtime);
455 			if (!err) {
456 				if (fclose(f) == EOF) {
457 					err = got_error_from_errno("fclose");
458 					got_ref_close(*ref);
459 					*ref = NULL;
460 				} else if (*ref)
461 					(*ref)->lf = lf;
462 			}
463 		}
464 	}
465 done:
466 	if (!err && *ref == NULL)
467 		err = got_error_not_ref(refname);
468 	if (err && lf)
469 		got_lockfile_unlock(lf, -1);
470 	free(packed_refs_path);
471 	free(path_refs);
472 	return err;
473 }
474 
475 void
476 got_ref_close(struct got_reference *ref)
477 {
478 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
479 		free(ref->ref.symref.name);
480 		free(ref->ref.symref.ref);
481 	} else
482 		free(ref->ref.ref.name);
483 	free(ref);
484 }
485 
486 struct got_reference *
487 got_ref_dup(struct got_reference *ref)
488 {
489 	struct got_reference *ret;
490 
491 	ret = calloc(1, sizeof(*ret));
492 	if (ret == NULL)
493 		return NULL;
494 
495 	ret->flags = ref->flags;
496 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
497 		ret->ref.symref.name = strdup(ref->ref.symref.name);
498 		if (ret->ref.symref.name == NULL) {
499 			free(ret);
500 			return NULL;
501 		}
502 		ret->ref.symref.ref = strdup(ref->ref.symref.ref);
503 		if (ret->ref.symref.ref == NULL) {
504 			free(ret->ref.symref.name);
505 			free(ret);
506 			return NULL;
507 		}
508 	} else {
509 		ret->ref.ref.name = strdup(ref->ref.ref.name);
510 		if (ret->ref.ref.name == NULL) {
511 			free(ret);
512 			return NULL;
513 		}
514 		memcpy(&ret->ref.ref.id, &ref->ref.ref.id,
515 		    sizeof(ret->ref.ref.id));
516 	}
517 
518 	return ret;
519 }
520 
521 const struct got_error *
522 got_reflist_entry_dup(struct got_reflist_entry **newp,
523     struct got_reflist_entry *re)
524 {
525 	const struct got_error *err = NULL;
526 	struct got_reflist_entry *new;
527 
528 	*newp = NULL;
529 
530 	new = malloc(sizeof(*new));
531 	if (new == NULL)
532 		return got_error_from_errno("malloc");
533 
534 	new->ref = got_ref_dup(re->ref);
535 	if (new->ref == NULL) {
536 		err = got_error_from_errno("got_ref_dup");
537 		free(new);
538 		return err;
539 	}
540 
541 	*newp = new;
542 	return NULL;
543 }
544 
545 const struct got_error *
546 got_ref_resolve_symbolic(struct got_reference **resolved,
547     struct got_repository *repo, struct got_reference *ref)
548 {
549 	struct got_reference *nextref;
550 	const struct got_error *err;
551 
552 	err = got_ref_open(&nextref, repo, ref->ref.symref.ref, 0);
553 	if (err)
554 		return err;
555 
556 	if (nextref->flags & GOT_REF_IS_SYMBOLIC)
557 		err = got_ref_resolve_symbolic(resolved, repo, nextref);
558 	else
559 		*resolved = got_ref_dup(nextref);
560 
561 	got_ref_close(nextref);
562 	return err;
563 }
564 
565 static const struct got_error *
566 ref_resolve(struct got_object_id **id, struct got_repository *repo,
567     struct got_reference *ref, int recursion)
568 {
569 	const struct got_error *err;
570 
571 	if (recursion <= 0)
572 		return got_error_msg(GOT_ERR_RECURSION,
573 		    "reference recursion limit reached");
574 
575 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
576 		struct got_reference *resolved = NULL;
577 		err = got_ref_resolve_symbolic(&resolved, repo, ref);
578 		if (err == NULL)
579 			err = ref_resolve(id, repo, resolved, --recursion);
580 		if (resolved)
581 			got_ref_close(resolved);
582 		return err;
583 	}
584 
585 	*id = calloc(1, sizeof(**id));
586 	if (*id == NULL)
587 		return got_error_from_errno("calloc");
588 	memcpy(*id, &ref->ref.ref.id, sizeof(**id));
589 	return NULL;
590 }
591 
592 const struct got_error *
593 got_ref_resolve(struct got_object_id **id, struct got_repository *repo,
594     struct got_reference *ref)
595 {
596 	return ref_resolve(id, repo, ref, GOT_REF_RECURSE_MAX);
597 }
598 
599 char *
600 got_ref_to_str(struct got_reference *ref)
601 {
602 	char *str;
603 
604 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
605 		return strdup(ref->ref.symref.ref);
606 
607 	if (got_object_id_str(&str, &ref->ref.ref.id) != NULL)
608 		return NULL;
609 
610 	return str;
611 }
612 
613 const char *
614 got_ref_get_name(struct got_reference *ref)
615 {
616 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
617 		return ref->ref.symref.name;
618 
619 	return ref->ref.ref.name;
620 }
621 
622 const char *
623 got_ref_get_symref_target(struct got_reference *ref)
624 {
625 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
626 		return ref->ref.symref.ref;
627 
628 	return NULL;
629 }
630 
631 time_t
632 got_ref_get_mtime(struct got_reference *ref)
633 {
634 	return ref->mtime;
635 }
636 
637 const struct got_error *
638 got_ref_cmp_by_name(void *arg, int *cmp, struct got_reference *re1,
639     struct got_reference* re2)
640 {
641 	const char *name1 = got_ref_get_name(re1);
642 	const char *name2 = got_ref_get_name(re2);
643 
644 	*cmp = got_path_cmp(name1, name2, strlen(name1), strlen(name2));
645 	return NULL;
646 }
647 
648 const struct got_error *
649 got_ref_cmp_tags(void *arg, int *cmp, struct got_reference *ref1,
650     struct got_reference *ref2)
651 {
652 	const struct got_error *err = NULL;
653 	struct got_repository *repo = arg;
654 	struct got_object_id *id1, *id2 = NULL;
655 	struct got_tag_object *tag1 = NULL, *tag2 = NULL;
656 	struct got_commit_object *commit1 = NULL, *commit2 = NULL;
657 	time_t time1, time2;
658 
659 	*cmp = 0;
660 
661 	err = got_ref_resolve(&id1, repo, ref1);
662 	if (err)
663 		return err;
664 	err = got_object_open_as_tag(&tag1, repo, id1);
665 	if (err) {
666 		if (err->code != GOT_ERR_OBJ_TYPE)
667 			goto done;
668 		/* "lightweight" tag */
669 		err = got_object_open_as_commit(&commit1, repo, id1);
670 		if (err)
671 			goto done;
672 		time1 = got_object_commit_get_committer_time(commit1);
673 	} else
674 		time1 = got_object_tag_get_tagger_time(tag1);
675 
676 	err = got_ref_resolve(&id2, repo, ref2);
677 	if (err)
678 		goto done;
679 	err = got_object_open_as_tag(&tag2, repo, id2);
680 	if (err) {
681 		if (err->code != GOT_ERR_OBJ_TYPE)
682 			goto done;
683 		/* "lightweight" tag */
684 		err = got_object_open_as_commit(&commit2, repo, id2);
685 		if (err)
686 			goto done;
687 		time2 = got_object_commit_get_committer_time(commit2);
688 	} else
689 		time2 = got_object_tag_get_tagger_time(tag2);
690 
691 	/* Put latest tags first. */
692 	if (time1 < time2)
693 		*cmp = 1;
694 	else if (time1 > time2)
695 		*cmp = -1;
696 	else
697 		err = got_ref_cmp_by_name(NULL, cmp, ref2, ref1);
698 done:
699 	free(id1);
700 	free(id2);
701 	if (tag1)
702 		got_object_tag_close(tag1);
703 	if (tag2)
704 		got_object_tag_close(tag2);
705 	if (commit1)
706 		got_object_commit_close(commit1);
707 	if (commit2)
708 		got_object_commit_close(commit2);
709 	return err;
710 }
711 
712 static const struct got_error *
713 get_committer_time(struct got_reference *ref, struct got_repository *repo)
714 {
715 	const struct got_error *err = NULL;
716 	int obj_type;
717 	struct got_commit_object *commit = NULL;
718 	struct got_tag_object *tag = NULL;
719 	struct got_object_id *id = NULL;
720 
721 	err = got_ref_resolve(&id, repo, ref);
722 	if (err)
723 		return err;
724 
725 	err = got_object_get_type(&obj_type, repo, id);
726 	if (err)
727 		goto done;
728 
729 	switch (obj_type) {
730 	case GOT_OBJ_TYPE_COMMIT:
731 		err = got_object_open_as_commit(&commit, repo, id);
732 		if (err)
733 			goto done;
734 		ref->committer_time =
735 		    got_object_commit_get_committer_time(commit);
736 		break;
737 	case GOT_OBJ_TYPE_TAG:
738 		err = got_object_open_as_tag(&tag, repo, id);
739 		if (err)
740 			goto done;
741 		ref->committer_time = got_object_tag_get_tagger_time(tag);
742 		break;
743 	default:
744 		/* best effort for other object types */
745 		ref->committer_time = got_ref_get_mtime(ref);
746 		break;
747 	}
748 done:
749 	free(id);
750 	if (commit)
751 		got_object_commit_close(commit);
752 	if (tag)
753 		got_object_tag_close(tag);
754 	return err;
755 }
756 
757 const struct got_error *
758 got_ref_cmp_by_commit_timestamp_descending(void *arg, int *cmp,
759     struct got_reference *ref1, struct got_reference *ref2)
760 {
761 	const struct got_error *err = NULL;
762 	struct got_repository *repo = arg;
763 
764 	*cmp = 0;
765 
766 	if (ref1->committer_time == 0) {
767 		err = get_committer_time(ref1, repo);
768 		if (err)
769 			return err;
770 	}
771 	if (ref2->committer_time == 0) {
772 		err = get_committer_time(ref2, repo);
773 		if (err)
774 			return err;
775 	}
776 
777 	if (ref1->committer_time < ref2->committer_time)
778 		*cmp = 1;
779 	else if (ref2->committer_time < ref1->committer_time)
780 		*cmp = -1;
781 	else
782 		return got_ref_cmp_by_name(arg, cmp, ref1, ref2);
783 
784 	return err;
785 }
786 
787 const struct got_error *
788 got_reflist_insert(struct got_reflist_entry **newp,
789     struct got_reflist_head *refs, struct got_reference *ref,
790     got_ref_cmp_cb cmp_cb, void *cmp_arg)
791 {
792 	const struct got_error *err;
793 	struct got_reflist_entry *new, *re;
794 	int cmp;
795 
796 	*newp = NULL;
797 
798 	if (cmp_cb != got_ref_cmp_by_name && (ref->flags & GOT_REF_IS_PACKED)) {
799 		/*
800 		 * If we are not sorting elements by name then we must still
801 		 * detect collisions between a packed ref and an on-disk ref
802 		 * using the same name. On-disk refs take precedence and are
803 		 * already present on the list before packed refs get added.
804 		 */
805 		TAILQ_FOREACH(re, refs, entry) {
806 			err = got_ref_cmp_by_name(NULL, &cmp, re->ref, ref);
807 			if (err)
808 				return err;
809 			if (cmp == 0)
810 				return NULL;
811 		}
812 	}
813 
814 	new = malloc(sizeof(*new));
815 	if (new == NULL)
816 		return got_error_from_errno("malloc");
817 	new->ref = ref;
818 	*newp = new;
819 
820 	/*
821 	 * We must de-duplicate entries on insert because packed-refs may
822 	 * contain redundant entries. On-disk refs take precedence.
823 	 * This code assumes that on-disk revs are read before packed-refs.
824 	 * We're iterating the list anyway, so insert elements sorted by name.
825 	 *
826 	 * Many callers will provide paths in a somewhat sorted order.
827 	 * Iterating backwards from the tail of the list should be more
828 	 * efficient than traversing through the entire list each time
829 	 * an element is inserted.
830 	 */
831 	re = TAILQ_LAST(refs, got_reflist_head);
832 	while (re) {
833 		err = (*cmp_cb)(cmp_arg, &cmp, re->ref, new->ref);
834 		if (err)
835 			return err;
836 		if (cmp == 0) {
837 			/* duplicate */
838 			free(new);
839 			*newp = NULL;
840 			return NULL;
841 		} else if (cmp < 0) {
842 			TAILQ_INSERT_AFTER(refs, re, new, entry);
843 			return NULL;
844 		}
845 		re = TAILQ_PREV(re, got_reflist_head, entry);
846 	}
847 
848 	TAILQ_INSERT_HEAD(refs, new, entry);
849 	return NULL;
850 }
851 
852 const struct got_error *
853 got_reflist_sort(struct got_reflist_head *refs,
854     got_ref_cmp_cb cmp_cb, void *cmp_arg)
855 {
856 	const struct got_error *err = NULL;
857 	struct got_reflist_entry *re, *tmp, *new;
858 	struct got_reflist_head sorted;
859 
860 	TAILQ_INIT(&sorted);
861 
862 	TAILQ_FOREACH_SAFE(re, refs, entry, tmp) {
863 		struct got_reference *ref = re->ref;
864 		TAILQ_REMOVE(refs, re, entry);
865 		free(re);
866 		err = got_reflist_insert(&new, &sorted, ref, cmp_cb, cmp_arg);
867 		if (err || new == NULL /* duplicate */)
868 			got_ref_close(ref);
869 		if (err)
870 			return err;
871 	}
872 
873 	TAILQ_CONCAT(refs, &sorted, entry);
874 	return NULL;
875 }
876 
877 static const struct got_error *
878 gather_on_disk_refs(struct got_reflist_head *refs, const char *path_refs,
879     const char *subdir, struct got_repository *repo,
880     got_ref_cmp_cb cmp_cb, void *cmp_arg)
881 {
882 	const struct got_error *err = NULL;
883 	DIR *d = NULL;
884 	char *path_subdir;
885 
886 	while (subdir[0] == '/')
887 		subdir++;
888 
889 	if (asprintf(&path_subdir, "%s/%s", path_refs, subdir) == -1)
890 		return got_error_from_errno("asprintf");
891 
892 	d = opendir(path_subdir);
893 	if (d == NULL)
894 		goto done;
895 
896 	for (;;) {
897 		struct dirent *dent;
898 		struct got_reference *ref;
899 		char *child;
900 		int type;
901 
902 		dent = readdir(d);
903 		if (dent == NULL)
904 			break;
905 
906 		if (strcmp(dent->d_name, ".") == 0 ||
907 		    strcmp(dent->d_name, "..") == 0)
908 			continue;
909 
910 		err = got_path_dirent_type(&type, path_subdir, dent);
911 		if (err)
912 			break;
913 
914 		switch (type) {
915 		case DT_REG:
916 			err = open_ref(&ref, path_refs, subdir, dent->d_name,
917 			    0);
918 			if (err)
919 				goto done;
920 			if (ref) {
921 				struct got_reflist_entry *new;
922 				err = got_reflist_insert(&new, refs, ref,
923 				    cmp_cb, cmp_arg);
924 				if (err || new == NULL /* duplicate */)
925 					got_ref_close(ref);
926 				if (err)
927 					goto done;
928 			}
929 			break;
930 		case DT_DIR:
931 			if (asprintf(&child, "%s%s%s", subdir,
932 			    subdir[0] == '\0' ? "" : "/", dent->d_name) == -1) {
933 				err = got_error_from_errno("asprintf");
934 				break;
935 			}
936 			err = gather_on_disk_refs(refs, path_refs, child, repo,
937 			    cmp_cb, cmp_arg);
938 			free(child);
939 			break;
940 		default:
941 			break;
942 		}
943 	}
944 done:
945 	if (d)
946 		closedir(d);
947 	free(path_subdir);
948 	return err;
949 }
950 
951 const struct got_error *
952 got_ref_list(struct got_reflist_head *refs, struct got_repository *repo,
953     const char *ref_namespace, got_ref_cmp_cb cmp_cb, void *cmp_arg)
954 {
955 	const struct got_error *err;
956 	char *packed_refs_path = NULL, *path_refs = NULL;
957 	char *abs_namespace = NULL, *buf = NULL;
958 	const char *ondisk_ref_namespace = NULL;
959 	char *line = NULL;
960 	FILE *f = NULL;
961 	struct got_reference *ref;
962 	struct got_reflist_entry *new;
963 
964 	if (ref_namespace == NULL || ref_namespace[0] == '\0') {
965 		path_refs = get_refs_dir_path(repo, GOT_REF_HEAD);
966 		if (path_refs == NULL) {
967 			err = got_error_from_errno("get_refs_dir_path");
968 			goto done;
969 		}
970 		err = open_ref(&ref, path_refs, "", GOT_REF_HEAD, 0);
971 		if (err)
972 			goto done;
973 		err = got_reflist_insert(&new, refs, ref, cmp_cb, cmp_arg);
974 		if (err || new == NULL /* duplicate */)
975 			got_ref_close(ref);
976 		if (err && err->code != GOT_ERR_NOT_REF)
977 			goto done;
978 	} else {
979 		/* Try listing a single reference. */
980 		const char *refname = ref_namespace;
981 		path_refs = get_refs_dir_path(repo, refname);
982 		if (path_refs == NULL) {
983 			err = got_error_from_errno("get_refs_dir_path");
984 			goto done;
985 		}
986 		err = open_ref(&ref, path_refs, "", refname, 0);
987 		if (err) {
988 			if (err->code != GOT_ERR_NOT_REF)
989 				goto done;
990 			/* Try to look up references in a given namespace. */
991 		} else {
992 			err = got_reflist_insert(&new, refs, ref,
993 			    cmp_cb, cmp_arg);
994 			if (err || new == NULL /* duplicate */)
995 				got_ref_close(ref);
996 			return err;
997 		}
998 	}
999 
1000 	if (ref_namespace) {
1001 		size_t len;
1002 		/* Canonicalize the path to eliminate double-slashes if any. */
1003 		if (asprintf(&abs_namespace, "/%s", ref_namespace) == -1) {
1004 			err = got_error_from_errno("asprintf");
1005 			goto done;
1006 		}
1007 		len = strlen(abs_namespace) + 1;
1008 		buf = malloc(len);
1009 		if (buf == NULL) {
1010 			err = got_error_from_errno("malloc");
1011 			goto done;
1012 		}
1013 		err = got_canonpath(abs_namespace, buf, len);
1014 		if (err)
1015 			goto done;
1016 		ondisk_ref_namespace = buf;
1017 		while (ondisk_ref_namespace[0] == '/')
1018 			ondisk_ref_namespace++;
1019 		if (strncmp(ondisk_ref_namespace, "refs/", 5) == 0)
1020 			ondisk_ref_namespace += 5;
1021 		else if (strcmp(ondisk_ref_namespace, "refs") == 0)
1022 			ondisk_ref_namespace = "";
1023 	}
1024 
1025 	/* Gather on-disk refs before parsing packed-refs. */
1026 	free(path_refs);
1027 	path_refs = get_refs_dir_path(repo, "");
1028 	if (path_refs == NULL) {
1029 		err = got_error_from_errno("get_refs_dir_path");
1030 		goto done;
1031 	}
1032 	err = gather_on_disk_refs(refs, path_refs,
1033 	    ondisk_ref_namespace ? ondisk_ref_namespace : "", repo,
1034 	    cmp_cb, cmp_arg);
1035 	if (err)
1036 		goto done;
1037 
1038 	/*
1039 	 * The packed-refs file may contain redundant entries, in which
1040 	 * case on-disk refs take precedence.
1041 	 */
1042 	packed_refs_path = got_repo_get_path_packed_refs(repo);
1043 	if (packed_refs_path == NULL) {
1044 		err = got_error_from_errno("got_repo_get_path_packed_refs");
1045 		goto done;
1046 	}
1047 
1048 	f = fopen(packed_refs_path, "re");
1049 	if (f) {
1050 		size_t linesize = 0;
1051 		ssize_t linelen;
1052 		struct stat sb;
1053 
1054 		if (fstat(fileno(f), &sb) == -1) {
1055 			err = got_error_from_errno2("fstat", packed_refs_path);
1056 			goto done;
1057 		}
1058 		for (;;) {
1059 			linelen = getline(&line, &linesize, f);
1060 			if (linelen == -1) {
1061 				if (feof(f))
1062 					break;
1063 				err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
1064 				goto done;
1065 			}
1066 			if (linelen > 0 && line[linelen - 1] == '\n')
1067 				line[linelen - 1] = '\0';
1068 			err = parse_packed_ref_line(&ref, NULL, line,
1069 			    sb.st_mtime);
1070 			if (err)
1071 				goto done;
1072 			if (ref) {
1073 				if (ref_namespace) {
1074 					const char *name;
1075 					name = got_ref_get_name(ref);
1076 					if (!got_path_is_child(name,
1077 					    ref_namespace,
1078 					    strlen(ref_namespace))) {
1079 						got_ref_close(ref);
1080 						continue;
1081 					}
1082 				}
1083 				err = got_reflist_insert(&new, refs, ref,
1084 				    cmp_cb, cmp_arg);
1085 				if (err || new == NULL /* duplicate */)
1086 					got_ref_close(ref);
1087 				if (err)
1088 					goto done;
1089 			}
1090 		}
1091 	}
1092 done:
1093 	free(packed_refs_path);
1094 	free(abs_namespace);
1095 	free(buf);
1096 	free(line);
1097 	free(path_refs);
1098 	if (f && fclose(f) == EOF && err == NULL)
1099 		err = got_error_from_errno("fclose");
1100 	return err;
1101 }
1102 
1103 void
1104 got_ref_list_free(struct got_reflist_head *refs)
1105 {
1106 	struct got_reflist_entry *re;
1107 
1108 	while ((re = TAILQ_FIRST(refs))) {
1109 		TAILQ_REMOVE(refs, re, entry);
1110 		got_ref_close(re->ref);
1111 		free(re);
1112 	}
1113 }
1114 
1115 int
1116 got_ref_is_symbolic(struct got_reference *ref)
1117 {
1118 	return (ref->flags & GOT_REF_IS_SYMBOLIC);
1119 }
1120 
1121 const struct got_error *
1122 got_ref_change_ref(struct got_reference *ref, struct got_object_id *id)
1123 {
1124 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
1125 		return got_error(GOT_ERR_BAD_REF_TYPE);
1126 
1127 	memcpy(&ref->ref.ref.id, id, sizeof(ref->ref.ref.id));
1128 	return NULL;
1129 }
1130 
1131 const struct got_error *
1132 got_ref_change_symref(struct got_reference *ref, const char *refname)
1133 {
1134 	char *new_name;
1135 
1136 	if ((ref->flags & GOT_REF_IS_SYMBOLIC) == 0)
1137 		return got_error(GOT_ERR_BAD_REF_TYPE);
1138 
1139 	new_name = strdup(refname);
1140 	if (new_name == NULL)
1141 		return got_error_from_errno("strdup");
1142 
1143 	free(ref->ref.symref.ref);
1144 	ref->ref.symref.ref = new_name;
1145 	return NULL;
1146 }
1147 
1148 const struct got_error *
1149 got_ref_change_symref_to_ref(struct got_reference *symref,
1150     struct got_object_id *id)
1151 {
1152 	if ((symref->flags & GOT_REF_IS_SYMBOLIC) == 0)
1153 		return got_error(GOT_ERR_BAD_REF_TYPE);
1154 
1155 	symref->ref.ref.name = symref->ref.symref.name;
1156 	memcpy(&symref->ref.ref.id, id, sizeof(symref->ref.ref.id));
1157 	symref->flags &= ~GOT_REF_IS_SYMBOLIC;
1158 	return NULL;
1159 }
1160 
1161 const struct got_error *
1162 got_ref_write(struct got_reference *ref, struct got_repository *repo)
1163 {
1164 	const struct got_error *err = NULL, *unlock_err = NULL;
1165 	const char *name = got_ref_get_name(ref);
1166 	char *path_refs = NULL, *path = NULL, *tmppath = NULL;
1167 	struct got_lockfile *lf = NULL;
1168 	FILE *f = NULL;
1169 	size_t n;
1170 	struct stat sb;
1171 
1172 	path_refs = get_refs_dir_path(repo, name);
1173 	if (path_refs == NULL) {
1174 		err = got_error_from_errno2("get_refs_dir_path", name);
1175 		goto done;
1176 	}
1177 
1178 	if (asprintf(&path, "%s/%s", path_refs, name) == -1) {
1179 		err = got_error_from_errno("asprintf");
1180 		goto done;
1181 	}
1182 
1183 	err = got_opentemp_named(&tmppath, &f, path, "");
1184 	if (err) {
1185 		char *parent;
1186 		if (!(err->code == GOT_ERR_ERRNO && errno == ENOENT))
1187 			goto done;
1188 		err = got_path_dirname(&parent, path);
1189 		if (err)
1190 			goto done;
1191 		err = got_path_mkdir(parent);
1192 		free(parent);
1193 		if (err)
1194 			goto done;
1195 		err = got_opentemp_named(&tmppath, &f, path, "");
1196 		if (err)
1197 			goto done;
1198 	}
1199 
1200 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
1201 		n = fprintf(f, "ref: %s\n", ref->ref.symref.ref);
1202 		if (n != strlen(ref->ref.symref.ref) + 6) {
1203 			err = got_ferror(f, GOT_ERR_IO);
1204 			goto done;
1205 		}
1206 	} else {
1207 		char *hex;
1208 		size_t len;
1209 
1210 		err = got_object_id_str(&hex, &ref->ref.ref.id);
1211 		if (err)
1212 			goto done;
1213 		len = strlen(hex);
1214 		n = fprintf(f, "%s\n", hex);
1215 		free(hex);
1216 		if (n != len + 1) {
1217 			err = got_ferror(f, GOT_ERR_IO);
1218 			goto done;
1219 		}
1220 	}
1221 
1222 	if (ref->lf == NULL) {
1223 		err = got_lockfile_lock(&lf, path, -1);
1224 		if (err)
1225 			goto done;
1226 	}
1227 
1228 	/* XXX: check if old content matches our expectations? */
1229 
1230 	if (stat(path, &sb) != 0) {
1231 		if (errno != ENOENT) {
1232 			err = got_error_from_errno2("stat", path);
1233 			goto done;
1234 		}
1235 		sb.st_mode = GOT_DEFAULT_FILE_MODE;
1236 	}
1237 
1238 	if (fchmod(fileno(f), sb.st_mode) != 0) {
1239 		err = got_error_from_errno2("fchmod", tmppath);
1240 		goto done;
1241 	}
1242 
1243 	if (rename(tmppath, path) != 0) {
1244 		err = got_error_from_errno3("rename", tmppath, path);
1245 		goto done;
1246 	}
1247 	free(tmppath);
1248 	tmppath = NULL;
1249 
1250 	if (stat(path, &sb) == -1) {
1251 		err = got_error_from_errno2("stat", path);
1252 		goto done;
1253 	}
1254 	ref->mtime = sb.st_mtime;
1255 done:
1256 	if (ref->lf == NULL && lf)
1257 		unlock_err = got_lockfile_unlock(lf, -1);
1258 	if (f) {
1259 		if (fclose(f) == EOF && err == NULL)
1260 			err = got_error_from_errno("fclose");
1261 	}
1262 	free(path_refs);
1263 	free(path);
1264 	if (tmppath) {
1265 		if (unlink(tmppath) == -1 && err == NULL)
1266 			err = got_error_from_errno2("unlink", tmppath);
1267 		free(tmppath);
1268 	}
1269 	return err ? err : unlock_err;
1270 }
1271 
1272 static const struct got_error *
1273 delete_packed_ref(struct got_reference *delref, struct got_repository *repo)
1274 {
1275 	const struct got_error *err = NULL, *unlock_err = NULL;
1276 	struct got_lockfile *lf = NULL;
1277 	FILE *f = NULL, *tmpf = NULL;
1278 	char *line = NULL, *packed_refs_path, *tmppath = NULL;
1279 	size_t linesize = 0;
1280 	struct got_reflist_head refs;
1281 	int found_delref = 0;
1282 
1283 	/* The packed-refs file does not cotain symbolic references. */
1284 	if (delref->flags & GOT_REF_IS_SYMBOLIC)
1285 		return got_error(GOT_ERR_BAD_REF_DATA);
1286 
1287 	TAILQ_INIT(&refs);
1288 
1289 	packed_refs_path = got_repo_get_path_packed_refs(repo);
1290 	if (packed_refs_path == NULL)
1291 		return got_error_from_errno("got_repo_get_path_packed_refs");
1292 
1293 	err = got_opentemp_named(&tmppath, &tmpf, packed_refs_path, "");
1294 	if (err)
1295 		goto done;
1296 
1297 	if (delref->lf == NULL) {
1298 		err = got_lockfile_lock(&lf, packed_refs_path, -1);
1299 		if (err)
1300 			goto done;
1301 	}
1302 
1303 	f = fopen(packed_refs_path, "re");
1304 	if (f == NULL) {
1305 		err = got_error_from_errno2("fopen", packed_refs_path);
1306 		goto done;
1307 	}
1308 	for (;;) {
1309 		ssize_t linelen;
1310 		struct got_reference *ref;
1311 		struct got_reflist_entry *new;
1312 
1313 		linelen = getline(&line, &linesize, f);
1314 		if (linelen == -1) {
1315 			if (feof(f))
1316 				break;
1317 			err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
1318 			goto done;
1319 		}
1320 		if (linelen > 0 && line[linelen - 1] == '\n')
1321 			line[linelen - 1] = '\0';
1322 		err = parse_packed_ref_line(&ref, NULL, line, 0);
1323 		if (err)
1324 			goto done;
1325 		if (ref == NULL)
1326 			continue;
1327 
1328 		if (strcmp(ref->ref.ref.name, delref->ref.ref.name) == 0 &&
1329 		    got_object_id_cmp(&ref->ref.ref.id,
1330 		    &delref->ref.ref.id) == 0) {
1331 			found_delref = 1;
1332 			got_ref_close(ref);
1333 			continue;
1334 		}
1335 
1336 		err = got_reflist_insert(&new, &refs, ref,
1337 		    got_ref_cmp_by_name, NULL);
1338 		if (err || new == NULL /* duplicate */)
1339 			got_ref_close(ref);
1340 		if (err)
1341 			goto done;
1342 	}
1343 
1344 	if (found_delref) {
1345 		struct got_reflist_entry *re;
1346 		size_t n;
1347 		struct stat sb;
1348 
1349 		n = fprintf(tmpf, "%s\n", GOT_PACKED_REFS_HEADER);
1350 		if (n != sizeof(GOT_PACKED_REFS_HEADER)) {
1351 			err = got_ferror(f, GOT_ERR_IO);
1352 			goto done;
1353 		}
1354 
1355 		TAILQ_FOREACH(re, &refs, entry) {
1356 			char *hex;
1357 			size_t len;
1358 
1359 			err = got_object_id_str(&hex, &re->ref->ref.ref.id);
1360 			if (err)
1361 				goto done;
1362 			len = strlen(hex);
1363 			n = fprintf(tmpf, "%s ", hex);
1364 			free(hex);
1365 			if (n != len + 1) {
1366 				err = got_ferror(f, GOT_ERR_IO);
1367 				goto done;
1368 			}
1369 
1370 			n = fprintf(tmpf, "%s\n", re->ref->ref.ref.name);
1371 			if (n != strlen(re->ref->ref.ref.name) + 1) {
1372 				err = got_ferror(f, GOT_ERR_IO);
1373 				goto done;
1374 			}
1375 		}
1376 
1377 		if (fflush(tmpf) != 0) {
1378 			err = got_error_from_errno("fflush");
1379 			goto done;
1380 		}
1381 
1382 		if (fstat(fileno(f), &sb) != 0) {
1383 			if (errno != ENOENT) {
1384 				err = got_error_from_errno2("fstat",
1385 				    packed_refs_path);
1386 				goto done;
1387 			}
1388 			sb.st_mode = GOT_DEFAULT_FILE_MODE;
1389 		}
1390 
1391 		if (fchmod(fileno(tmpf), sb.st_mode) != 0) {
1392 			err = got_error_from_errno2("fchmod", tmppath);
1393 			goto done;
1394 		}
1395 
1396 		if (rename(tmppath, packed_refs_path) != 0) {
1397 			err = got_error_from_errno3("rename", tmppath,
1398 			    packed_refs_path);
1399 			goto done;
1400 		}
1401 		free(tmppath);
1402 		tmppath = NULL;
1403 	}
1404 done:
1405 	if (delref->lf == NULL && lf)
1406 		unlock_err = got_lockfile_unlock(lf, -1);
1407 	if (f) {
1408 		if (fclose(f) == EOF && err == NULL)
1409 			err = got_error_from_errno("fclose");
1410 	}
1411 	if (tmppath && unlink(tmppath) == -1 && err == NULL)
1412 		err = got_error_from_errno2("unlink", tmppath);
1413 	if (tmpf && fclose(tmpf) == EOF && err == NULL)
1414 		err = got_error_from_errno("fclose");
1415 	free(tmppath);
1416 	free(packed_refs_path);
1417 	free(line);
1418 	got_ref_list_free(&refs);
1419 	return err ? err : unlock_err;
1420 }
1421 
1422 static const struct got_error *
1423 delete_loose_ref(struct got_reference *ref, struct got_repository *repo)
1424 {
1425 	const struct got_error *err = NULL, *unlock_err = NULL;
1426 	const char *name = got_ref_get_name(ref);
1427 	char *path_refs = NULL, *path = NULL;
1428 	struct got_lockfile *lf = NULL;
1429 
1430 	path_refs = get_refs_dir_path(repo, name);
1431 	if (path_refs == NULL) {
1432 		err = got_error_from_errno2("get_refs_dir_path", name);
1433 		goto done;
1434 	}
1435 
1436 	if (asprintf(&path, "%s/%s", path_refs, name) == -1) {
1437 		err = got_error_from_errno("asprintf");
1438 		goto done;
1439 	}
1440 
1441 	if (ref->lf == NULL) {
1442 		err = got_lockfile_lock(&lf, path, -1);
1443 		if (err)
1444 			goto done;
1445 	}
1446 
1447 	/* XXX: check if old content matches our expectations? */
1448 
1449 	if (unlink(path) == -1)
1450 		err = got_error_from_errno2("unlink", path);
1451 done:
1452 	if (ref->lf == NULL && lf)
1453 		unlock_err = got_lockfile_unlock(lf, -1);
1454 
1455 	free(path_refs);
1456 	free(path);
1457 	return err ? err : unlock_err;
1458 }
1459 
1460 const struct got_error *
1461 got_ref_delete(struct got_reference *ref, struct got_repository *repo)
1462 {
1463 	const struct got_error *err = NULL;
1464 	struct got_reference *ref2;
1465 
1466 	if (ref->flags & GOT_REF_IS_PACKED) {
1467 		err = delete_packed_ref(ref, repo);
1468 		if (err)
1469 			return err;
1470 
1471 		err = got_ref_open(&ref2, repo, got_ref_get_name(ref), 0);
1472 		if (err) {
1473 			if (err->code == GOT_ERR_NOT_REF)
1474 				return NULL;
1475 			return err;
1476 		}
1477 
1478 		err = delete_loose_ref(ref2, repo);
1479 		got_ref_close(ref2);
1480 		return err;
1481 	} else {
1482 		err = delete_loose_ref(ref, repo);
1483 		if (err)
1484 			return err;
1485 
1486 		err = got_ref_open(&ref2, repo, got_ref_get_name(ref), 0);
1487 		if (err) {
1488 			if (err->code == GOT_ERR_NOT_REF)
1489 				return NULL;
1490 			return err;
1491 		}
1492 
1493 		err = delete_packed_ref(ref2, repo);
1494 		got_ref_close(ref2);
1495 		return err;
1496 	}
1497 }
1498 
1499 const struct got_error *
1500 got_ref_unlock(struct got_reference *ref)
1501 {
1502 	const struct got_error *err;
1503 	err = got_lockfile_unlock(ref->lf, -1);
1504 	ref->lf = NULL;
1505 	return err;
1506 }
1507 
1508 struct got_reflist_object_id_map {
1509 	struct got_object_idset *idset;
1510 };
1511 
1512 struct got_reflist_object_id_map_entry {
1513 	struct got_reflist_head refs;
1514 };
1515 
1516 static const struct got_error *
1517 add_object_id_map_entry(struct got_object_idset *idset,
1518     struct got_object_id *id, struct got_reflist_entry *re)
1519 {
1520 	const struct got_error *err = NULL;
1521 	struct got_reflist_object_id_map_entry *ent;
1522 	struct got_reflist_entry *new;
1523 
1524 	ent = got_object_idset_get(idset, id);
1525 	if (ent == NULL) {
1526 		ent = malloc(sizeof(*ent));
1527 		if (ent == NULL)
1528 			return got_error_from_errno("malloc");
1529 
1530 		TAILQ_INIT(&ent->refs);
1531 		err = got_object_idset_add(idset, id, ent);
1532 		if (err) {
1533 			free(ent);
1534 			return err;
1535 		}
1536 	}
1537 
1538 	err = got_reflist_entry_dup(&new, re);
1539 	if (err)
1540 		return err;
1541 
1542 	TAILQ_INSERT_TAIL(&ent->refs, new, entry);
1543 	return NULL;
1544 }
1545 
1546 const struct got_error *
1547 got_reflist_object_id_map_create(struct got_reflist_object_id_map **map,
1548     struct got_reflist_head *refs, struct got_repository *repo)
1549 {
1550 	const struct got_error *err = NULL;
1551 	struct got_object_idset *idset;
1552 	struct got_object_id *id = NULL;
1553 	struct got_reflist_entry *re;
1554 
1555 	idset = got_object_idset_alloc();
1556 	if (idset == NULL)
1557 		return got_error_from_errno("got_object_idset_alloc");
1558 
1559 	*map = malloc(sizeof(**map));
1560 	if (*map == NULL) {
1561 		got_object_idset_free(idset);
1562 		return got_error_from_errno("malloc");
1563 	}
1564 	(*map)->idset = idset;
1565 
1566 	TAILQ_FOREACH(re, refs, entry) {
1567 		struct got_tag_object *tag = NULL;
1568 
1569 		err = got_ref_resolve(&id, repo, re->ref);
1570 		if (err)
1571 			goto done;
1572 
1573 		err = add_object_id_map_entry(idset, id, re);
1574 		if (err)
1575 			goto done;
1576 
1577 		if (strstr(got_ref_get_name(re->ref), "/tags/") == NULL) {
1578 			free(id);
1579 			id = NULL;
1580 			continue;
1581 		}
1582 
1583 		err = got_object_open_as_tag(&tag, repo, id);
1584 		if (err) {
1585 			if (err->code != GOT_ERR_OBJ_TYPE)
1586 				goto done;
1587 			/* Ref points at something other than a tag. */
1588 			err = NULL;
1589 			tag = NULL;
1590 			free(id);
1591 			id = NULL;
1592 			continue;
1593 		}
1594 
1595 		err = add_object_id_map_entry(idset,
1596 		    got_object_tag_get_object_id(tag), re);
1597 		got_object_tag_close(tag);
1598 		if (err)
1599 			goto done;
1600 
1601 		free(id);
1602 		id = NULL;
1603 	}
1604 done:
1605 	free(id);
1606 	if (err) {
1607 		got_reflist_object_id_map_free(*map);
1608 		*map = NULL;
1609 	}
1610 	return err;
1611 }
1612 
1613 struct got_reflist_head *
1614 got_reflist_object_id_map_lookup(struct got_reflist_object_id_map *map,
1615     struct got_object_id *id)
1616 {
1617 	struct got_reflist_object_id_map_entry *ent;
1618 	ent = got_object_idset_get(map->idset, id);
1619 	if (ent)
1620 		return &ent->refs;
1621 	return NULL;
1622 }
1623 
1624 static const struct got_error *
1625 free_id_map_entry(struct got_object_id *id, void *data, void *arg)
1626 {
1627 	struct got_reflist_object_id_map_entry *ent = data;
1628 
1629 	got_ref_list_free(&ent->refs);
1630 	free(ent);
1631 	return NULL;
1632 }
1633 
1634 void
1635 got_reflist_object_id_map_free(struct got_reflist_object_id_map *map)
1636 {
1637 	got_object_idset_for_each(map->idset, free_id_map_entry, NULL);
1638 	got_object_idset_free(map->idset);
1639 	free(map);
1640 }