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 <ctype.h>
23 #include <dirent.h>
24 #include <limits.h>
25 #include <sha1.h>
26 #include <stdio.h>
27 #include <stdlib.h>
28 #include <string.h>
29 #include <unistd.h>
30 #include <util.h>
31 #include <zlib.h>
32 #include <time.h>
33 #include <libgen.h>
34 
35 #include "got_error.h"
36 #include "got_object.h"
37 #include "got_repository.h"
38 #include "got_reference.h"
39 #include "got_opentemp.h"
40 #include "got_path.h"
41 
42 #include "got_lib_sha1.h"
43 #include "got_lib_delta.h"
44 #include "got_lib_inflate.h"
45 #include "got_lib_object.h"
46 #include "got_lib_object_idset.h"
47 #include "got_lib_lockfile.h"
48 
49 #ifndef nitems
50 #define nitems(_a) (sizeof(_a) / sizeof((_a)[0]))
51 #endif
52 
53 #define GOT_REF_HEADS	"heads"
54 #define GOT_REF_TAGS	"tags"
55 #define GOT_REF_REMOTES	"remotes"
56 
57 /*
58  * We do not resolve tags yet, and don't yet care about sorting refs either,
59  * so packed-refs files we write contain a minimal header which disables all
60  * packed-refs "traits" supported by Git.
61  */
62 #define GOT_PACKED_REFS_HEADER	"# pack-refs with:"
63 
64 /* A symbolic reference. */
65 struct got_symref {
66 	char *name;
67 	char *ref;
68 };
69 
70 #define GOT_REF_RECURSE_MAX	20
71 
72 /* A non-symbolic reference (there is no better designation). */
73 struct got_ref {
74 	char *name;
75 	u_int8_t sha1[SHA1_DIGEST_LENGTH];
76 };
77 
78 /* A reference which points to an arbitrary object. */
79 struct got_reference {
80 	unsigned int flags;
81 #define GOT_REF_IS_SYMBOLIC	0x01
82 #define GOT_REF_IS_PACKED	0x02
83 
84 	union {
85 		struct got_ref ref;
86 		struct got_symref symref;
87 	} ref;
88 
89 	struct got_lockfile *lf;
90 };
91 
92 static const struct got_error *
93 alloc_ref(struct got_reference **ref, const char *name,
94     struct got_object_id *id, int flags)
95 {
96 	const struct got_error *err = NULL;
97 
98 	*ref = calloc(1, sizeof(**ref));
99 	if (*ref == NULL)
100 		return got_error_from_errno("calloc");
101 
102 	memcpy((*ref)->ref.ref.sha1, id->sha1, sizeof((*ref)->ref.ref.sha1));
103 	(*ref)->flags = flags;
104 	(*ref)->ref.ref.name = strdup(name);
105 	if ((*ref)->ref.ref.name == NULL) {
106 		err = got_error_from_errno("strdup");
107 		got_ref_close(*ref);
108 		*ref = NULL;
109 	}
110 	return err;
111 }
112 
113 static const struct got_error *
114 alloc_symref(struct got_reference **ref, const char *name,
115     const char *target_ref, int flags)
116 {
117 	const struct got_error *err = NULL;
118 
119 	*ref = calloc(1, sizeof(**ref));
120 	if (*ref == NULL)
121 		return got_error_from_errno("calloc");
122 
123 	(*ref)->flags = GOT_REF_IS_SYMBOLIC | flags;
124 	(*ref)->ref.symref.name = strdup(name);
125 	if ((*ref)->ref.symref.name == NULL) {
126 		err = got_error_from_errno("strdup");
127 		got_ref_close(*ref);
128 		*ref = NULL;
129 		return err;
130 	}
131 	(*ref)->ref.symref.ref = strdup(target_ref);
132 	if ((*ref)->ref.symref.ref == NULL) {
133 		err = got_error_from_errno("strdup");
134 		got_ref_close(*ref);
135 		*ref = NULL;
136 	}
137 	return err;
138 }
139 
140 static const struct got_error *
141 parse_symref(struct got_reference **ref, const char *name, const char *line)
142 {
143 	if (line[0] == '\0')
144 		return got_error(GOT_ERR_BAD_REF_DATA);
145 
146 	return alloc_symref(ref, name, line, 0);
147 }
148 
149 static const struct got_error *
150 parse_ref_line(struct got_reference **ref, const char *name, const char *line)
151 {
152 	struct got_object_id id;
153 
154 	if (strncmp(line, "ref: ", 5) == 0) {
155 		line += 5;
156 		return parse_symref(ref, name, line);
157 	}
158 
159 	if (!got_parse_sha1_digest(id.sha1, line))
160 		return got_error(GOT_ERR_BAD_REF_DATA);
161 
162 	return alloc_ref(ref, name, &id, 0);
163 }
164 
165 static const struct got_error *
166 parse_ref_file(struct got_reference **ref, const char *name,
167     const char *absname, const char *abspath, int lock)
168 {
169 	const struct got_error *err = NULL;
170 	FILE *f;
171 	char *line = NULL;
172 	size_t linesize = 0;
173 	ssize_t linelen;
174 	struct got_lockfile *lf = NULL;
175 
176 	if (lock) {
177 		err = got_lockfile_lock(&lf, abspath);
178 		if (err) {
179 			if (err->code == GOT_ERR_ERRNO && errno == ENOENT)
180 				err = got_error_not_ref(name);
181 			return err;
182 		}
183 	}
184 
185 	f = fopen(abspath, "rb");
186 	if (f == NULL) {
187 		if (errno != ENOTDIR && errno != ENOENT)
188 			err = got_error_from_errno2("fopen", abspath);
189 		else
190 			err = got_error_not_ref(name);
191 		if (lock)
192 			got_lockfile_unlock(lf);
193 		return err;
194 	}
195 
196 	linelen = getline(&line, &linesize, f);
197 	if (linelen == -1) {
198 		if (feof(f))
199 			err = NULL; /* ignore empty files (could be locks) */
200 		else {
201 			if (errno == EISDIR)
202 				err = got_error(GOT_ERR_NOT_REF);
203 			else if (ferror(f))
204 				err = got_ferror(f, GOT_ERR_IO);
205 			else
206 				err = got_error_from_errno2("getline", abspath);
207 		}
208 		if (lock)
209 			got_lockfile_unlock(lf);
210 		goto done;
211 	}
212 	while (linelen > 0 && line[linelen - 1] == '\n') {
213 		line[linelen - 1] = '\0';
214 		linelen--;
215 	}
216 
217 	err = parse_ref_line(ref, absname, line);
218 	if (lock) {
219 		if (err)
220 			got_lockfile_unlock(lf);
221 		else {
222 			if (*ref)
223 				(*ref)->lf = lf;
224 			else
225 				got_lockfile_unlock(lf);
226 		}
227 	}
228 done:
229 	free(line);
230 	if (fclose(f) == EOF && err == NULL) {
231 		err = got_error_from_errno("fclose");
232 		if (*ref) {
233 			if (lock)
234 				got_ref_unlock(*ref);
235 			got_ref_close(*ref);
236 			*ref = NULL;
237 		}
238 	}
239 	return err;
240 }
241 
242 static int
243 is_well_known_ref(const char *refname)
244 {
245 	return (strcmp(refname, GOT_REF_HEAD) == 0 ||
246 	    strcmp(refname, GOT_REF_ORIG_HEAD) == 0 ||
247 	    strcmp(refname, GOT_REF_MERGE_HEAD) == 0 ||
248 	    strcmp(refname, GOT_REF_FETCH_HEAD) == 0);
249 }
250 
251 static char *
252 get_refs_dir_path(struct got_repository *repo, const char *refname)
253 {
254 	if (is_well_known_ref(refname) || strncmp(refname, "refs/", 5) == 0)
255 		return strdup(got_repo_get_path_git_dir(repo));
256 
257 	return got_repo_get_path_refs(repo);
258 }
259 
260 static int
261 is_valid_ref_name(const char *name)
262 {
263 	const char *s, *seg;
264 	const char forbidden[] = { ' ', '~', '^', ':', '?', '*', '[' , '\\' };
265 	const char *forbidden_seq[] = { "//", "..", "@{" };
266 	const char *lfs = GOT_LOCKFILE_SUFFIX;
267 	const size_t lfs_len = sizeof(GOT_LOCKFILE_SUFFIX) - 1;
268 	size_t i;
269 
270 	if (name[0] == '@' && name[1] == '\0')
271 		return 0;
272 
273 	s = name;
274 	seg = s;
275 	if (seg[0] == '\0' || seg[0] == '.' || seg[0] == '/')
276 		return 0;
277 	while (*s) {
278 		for (i = 0; i < nitems(forbidden); i++) {
279 			if (*s == forbidden[i])
280 				return 0;
281 		}
282 		for (i = 0; i < nitems(forbidden_seq); i++) {
283 			if (s[0] == forbidden_seq[i][0] &&
284 			    s[1] == forbidden_seq[i][1])
285 				return 0;
286 		}
287 		if (iscntrl((unsigned char)s[0]))
288 			return 0;
289 		if (s[0] == '.' && s[1] == '\0')
290 			return 0;
291 		if (*s == '/') {
292 			const char *nextseg = s + 1;
293 			if (nextseg[0] == '\0' || nextseg[0] == '.' ||
294 			    nextseg[0] == '/')
295 				return 0;
296 			if (seg <= s - lfs_len &&
297 			    strncmp(s - lfs_len, lfs, lfs_len) == 0)
298 				return 0;
299 			seg = nextseg;
300 		}
301 		s++;
302 	}
303 
304 	if (seg <= s - lfs_len &&
305 	    strncmp(s - lfs_len, lfs, lfs_len) == 0)
306 		return 0;
307 
308 	return 1;
309 }
310 
311 const struct got_error *
312 got_ref_alloc(struct got_reference **ref, const char *name,
313     struct got_object_id *id)
314 {
315 	if (!is_valid_ref_name(name))
316 		return got_error_path(name, GOT_ERR_BAD_REF_NAME);
317 
318 	return alloc_ref(ref, name, id, 0);
319 }
320 
321 const struct got_error *
322 got_ref_alloc_symref(struct got_reference **ref, const char *name,
323 	struct got_reference *target_ref)
324 {
325 	if (!is_valid_ref_name(name))
326 		return got_error_path(name, GOT_ERR_BAD_REF_NAME);
327 
328 	return alloc_symref(ref, name, got_ref_get_name(target_ref), 0);
329 }
330 
331 static const struct got_error *
332 parse_packed_ref_line(struct got_reference **ref, const char *abs_refname,
333     const char *line)
334 {
335 	struct got_object_id id;
336 	const char *name;
337 
338 	*ref = NULL;
339 
340 	if (line[0] == '#' || line[0] == '^')
341 		return NULL;
342 
343 	if (!got_parse_sha1_digest(id.sha1, line))
344 		return got_error(GOT_ERR_BAD_REF_DATA);
345 
346 	if (abs_refname) {
347 		if (strcmp(line + SHA1_DIGEST_STRING_LENGTH, abs_refname) != 0)
348 			return NULL;
349 		name = abs_refname;
350 	} else
351 		name = line + SHA1_DIGEST_STRING_LENGTH;
352 
353 	return alloc_ref(ref, name, &id, GOT_REF_IS_PACKED);
354 }
355 
356 static const struct got_error *
357 open_packed_ref(struct got_reference **ref, FILE *f, const char **subdirs,
358     int nsubdirs, const char *refname)
359 {
360 	const struct got_error *err = NULL;
361 	char *abs_refname;
362 	char *line = NULL;
363 	size_t linesize = 0;
364 	ssize_t linelen;
365 	int i, ref_is_absolute = (strncmp(refname, "refs/", 5) == 0);
366 
367 	*ref = NULL;
368 
369 	if (ref_is_absolute)
370 		abs_refname = (char *)refname;
371 	do {
372 		linelen = getline(&line, &linesize, f);
373 		if (linelen == -1) {
374 			if (feof(f))
375 				break;
376 			err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
377 			break;
378 		}
379 		if (linelen > 0 && line[linelen - 1] == '\n')
380 			line[linelen - 1] = '\0';
381 		for (i = 0; i < nsubdirs; i++) {
382 			if (!ref_is_absolute &&
383 			    asprintf(&abs_refname, "refs/%s/%s", subdirs[i],
384 			    refname) == -1)
385 				return got_error_from_errno("asprintf");
386 			err = parse_packed_ref_line(ref, abs_refname, line);
387 			if (!ref_is_absolute)
388 				free(abs_refname);
389 			if (err || *ref != NULL)
390 				break;
391 		}
392 		if (err)
393 			break;
394 	} while (*ref == NULL);
395 	free(line);
396 
397 	return err;
398 }
399 
400 static const struct got_error *
401 open_ref(struct got_reference **ref, const char *path_refs, const char *subdir,
402     const char *name, int lock)
403 {
404 	const struct got_error *err = NULL;
405 	char *path = NULL;
406 	char *absname = NULL;
407 	int ref_is_absolute = (strncmp(name, "refs/", 5) == 0);
408 	int ref_is_well_known = (subdir[0] == '\0' && is_well_known_ref(name));
409 
410 	*ref = NULL;
411 
412 	if (ref_is_absolute || ref_is_well_known) {
413 		if (asprintf(&path, "%s/%s", path_refs, name) == -1)
414 			return got_error_from_errno("asprintf");
415 		absname = (char *)name;
416 	} else {
417 		if (asprintf(&path, "%s/%s%s%s", path_refs, subdir,
418 		    subdir[0] ? "/" : "", name) == -1)
419 			return got_error_from_errno("asprintf");
420 
421 		if (asprintf(&absname, "refs/%s%s%s",
422 		    subdir, subdir[0] ? "/" : "", name) == -1) {
423 			err = got_error_from_errno("asprintf");
424 			goto done;
425 		}
426 	}
427 
428 	err = parse_ref_file(ref, name, absname, path, lock);
429 done:
430 	if (!ref_is_absolute && !ref_is_well_known)
431 		free(absname);
432 	free(path);
433 	return err;
434 }
435 
436 const struct got_error *
437 got_ref_open(struct got_reference **ref, struct got_repository *repo,
438    const char *refname, int lock)
439 {
440 	const struct got_error *err = NULL;
441 	char *path_refs = NULL;
442 	const char *subdirs[] = {
443 	    GOT_REF_HEADS, GOT_REF_TAGS, GOT_REF_REMOTES
444 	};
445 	size_t i;
446 	int well_known = is_well_known_ref(refname);
447 	struct got_lockfile *lf = NULL;
448 
449 	*ref = NULL;
450 
451 	path_refs = get_refs_dir_path(repo, refname);
452 	if (path_refs == NULL) {
453 		err = got_error_from_errno2("get_refs_dir_path", refname);
454 		goto done;
455 	}
456 
457 	if (well_known) {
458 		err = open_ref(ref, path_refs, "", refname, lock);
459 	} else {
460 		char *packed_refs_path;
461 		FILE *f;
462 
463 		/* Search on-disk refs before packed refs! */
464 		for (i = 0; i < nitems(subdirs); i++) {
465 			err = open_ref(ref, path_refs, subdirs[i], refname,
466 			    lock);
467 			if ((err && err->code != GOT_ERR_NOT_REF) || *ref)
468 				goto done;
469 		}
470 
471 		packed_refs_path = got_repo_get_path_packed_refs(repo);
472 		if (packed_refs_path == NULL) {
473 			err = got_error_from_errno(
474 			    "got_repo_get_path_packed_refs");
475 			goto done;
476 		}
477 
478 		if (lock) {
479 			err = got_lockfile_lock(&lf, packed_refs_path);
480 			if (err)
481 				goto done;
482 		}
483 		f = fopen(packed_refs_path, "rb");
484 		free(packed_refs_path);
485 		if (f != NULL) {
486 			err = open_packed_ref(ref, f, subdirs, nitems(subdirs),
487 			    refname);
488 			if (!err) {
489 				if (fclose(f) == EOF) {
490 					err = got_error_from_errno("fclose");
491 					got_ref_close(*ref);
492 					*ref = NULL;
493 				} else if (*ref)
494 					(*ref)->lf = lf;
495 			}
496 		}
497 	}
498 done:
499 	if (!err && *ref == NULL)
500 		err = got_error_not_ref(refname);
501 	if (err && lf)
502 		got_lockfile_unlock(lf);
503 	free(path_refs);
504 	return err;
505 }
506 
507 void
508 got_ref_close(struct got_reference *ref)
509 {
510 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
511 		free(ref->ref.symref.name);
512 		free(ref->ref.symref.ref);
513 	} else
514 		free(ref->ref.ref.name);
515 	free(ref);
516 }
517 
518 struct got_reference *
519 got_ref_dup(struct got_reference *ref)
520 {
521 	struct got_reference *ret;
522 
523 	ret = calloc(1, sizeof(*ret));
524 	if (ret == NULL)
525 		return NULL;
526 
527 	ret->flags = ref->flags;
528 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
529 		ret->ref.symref.name = strdup(ref->ref.symref.name);
530 		if (ret->ref.symref.name == NULL) {
531 			free(ret);
532 			return NULL;
533 		}
534 		ret->ref.symref.ref = strdup(ref->ref.symref.ref);
535 		if (ret->ref.symref.ref == NULL) {
536 			free(ret->ref.symref.name);
537 			free(ret);
538 			return NULL;
539 		}
540 	} else {
541 		ret->ref.ref.name = strdup(ref->ref.ref.name);
542 		if (ret->ref.ref.name == NULL) {
543 			free(ret);
544 			return NULL;
545 		}
546 		memcpy(ret->ref.ref.sha1, ref->ref.ref.sha1,
547 		    sizeof(ret->ref.ref.sha1));
548 	}
549 
550 	return ret;
551 }
552 
553 const struct got_error *
554 got_reflist_entry_dup(struct got_reflist_entry **newp,
555     struct got_reflist_entry *re)
556 {
557 	const struct got_error *err = NULL;
558 	struct got_reflist_entry *new;
559 
560 	*newp = NULL;
561 
562 	new = malloc(sizeof(*new));
563 	if (new == NULL)
564 		return got_error_from_errno("malloc");
565 
566 	new->ref = got_ref_dup(re->ref);
567 	if (new->ref == NULL) {
568 		err = got_error_from_errno("got_ref_dup");
569 		free(new);
570 		return err;
571 	}
572 
573 	*newp = new;
574 	return NULL;
575 }
576 
577 static const struct got_error *
578 resolve_symbolic_ref(struct got_reference **resolved,
579     struct got_repository *repo, struct got_reference *ref)
580 {
581 	struct got_reference *nextref;
582 	const struct got_error *err;
583 
584 	err = got_ref_open(&nextref, repo, ref->ref.symref.ref, 0);
585 	if (err)
586 		return err;
587 
588 	if (nextref->flags & GOT_REF_IS_SYMBOLIC)
589 		err = resolve_symbolic_ref(resolved, repo, nextref);
590 	else
591 		*resolved = got_ref_dup(nextref);
592 
593 	got_ref_close(nextref);
594 	return err;
595 }
596 
597 static const struct got_error *
598 ref_resolve(struct got_object_id **id, struct got_repository *repo,
599     struct got_reference *ref, int recursion)
600 {
601 	const struct got_error *err;
602 
603 	if (recursion <= 0)
604 		return got_error_msg(GOT_ERR_RECURSION,
605 		    "reference recursion limit reached");
606 
607 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
608 		struct got_reference *resolved = NULL;
609 		err = resolve_symbolic_ref(&resolved, repo, ref);
610 		if (err == NULL)
611 			err = ref_resolve(id, repo, resolved, --recursion);
612 		if (resolved)
613 			got_ref_close(resolved);
614 		return err;
615 	}
616 
617 	*id = calloc(1, sizeof(**id));
618 	if (*id == NULL)
619 		return got_error_from_errno("calloc");
620 	memcpy((*id)->sha1, ref->ref.ref.sha1, sizeof((*id)->sha1));
621 	return NULL;
622 }
623 
624 const struct got_error *
625 got_ref_resolve(struct got_object_id **id, struct got_repository *repo,
626     struct got_reference *ref)
627 {
628 	return ref_resolve(id, repo, ref, GOT_REF_RECURSE_MAX);
629 }
630 
631 char *
632 got_ref_to_str(struct got_reference *ref)
633 {
634 	char *str;
635 
636 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
637 		return strdup(ref->ref.symref.ref);
638 
639 	str = malloc(SHA1_DIGEST_STRING_LENGTH);
640 	if (str == NULL)
641 		return NULL;
642 
643 	if (got_sha1_digest_to_str(ref->ref.ref.sha1, str,
644 	    SHA1_DIGEST_STRING_LENGTH) == NULL) {
645 		free(str);
646 		return NULL;
647 	}
648 
649 	return str;
650 }
651 
652 const char *
653 got_ref_get_name(struct got_reference *ref)
654 {
655 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
656 		return ref->ref.symref.name;
657 
658 	return ref->ref.ref.name;
659 }
660 
661 const char *
662 got_ref_get_symref_target(struct got_reference *ref)
663 {
664 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
665 		return ref->ref.symref.ref;
666 
667 	return NULL;
668 }
669 
670 const struct got_error *
671 got_ref_cmp_by_name(void *arg, int *cmp, struct got_reference *re1,
672     struct got_reference* re2)
673 {
674 	const char *name1 = got_ref_get_name(re1);
675 	const char *name2 = got_ref_get_name(re2);
676 
677 	*cmp = got_path_cmp(name1, name2, strlen(name1), strlen(name2));
678 	return NULL;
679 }
680 
681 const struct got_error *
682 got_ref_cmp_tags(void *arg, int *cmp, struct got_reference *ref1,
683     struct got_reference *ref2)
684 {
685 	const struct got_error *err = NULL;
686 	struct got_repository *repo = arg;
687 	struct got_object_id *id1, *id2 = NULL;
688 	struct got_tag_object *tag1 = NULL, *tag2 = NULL;
689 	struct got_commit_object *commit1 = NULL, *commit2 = NULL;
690 	time_t time1, time2;
691 
692 	*cmp = 0;
693 
694 	err = got_ref_resolve(&id1, repo, ref1);
695 	if (err)
696 		return err;
697 	err = got_object_open_as_tag(&tag1, repo, id1);
698 	if (err) {
699 		if (err->code != GOT_ERR_OBJ_TYPE)
700 			goto done;
701 		/* "lightweight" tag */
702 		err = got_object_open_as_commit(&commit1, repo, id1);
703 		if (err)
704 			goto done;
705 		time1 = got_object_commit_get_committer_time(commit1);
706 	} else
707 		time1 = got_object_tag_get_tagger_time(tag1);
708 
709 	err = got_ref_resolve(&id2, repo, ref2);
710 	if (err)
711 		goto done;
712 	err = got_object_open_as_tag(&tag2, repo, id2);
713 	if (err) {
714 		if (err->code != GOT_ERR_OBJ_TYPE)
715 			goto done;
716 		/* "lightweight" tag */
717 		err = got_object_open_as_commit(&commit2, repo, id2);
718 		if (err)
719 			goto done;
720 		time2 = got_object_commit_get_committer_time(commit2);
721 	} else
722 		time2 = got_object_tag_get_tagger_time(tag2);
723 
724 	/* Put latest tags first. */
725 	if (time1 < time2)
726 		*cmp = 1;
727 	else if (time1 > time2)
728 		*cmp = -1;
729 	else
730 		err = got_ref_cmp_by_name(NULL, cmp, ref2, ref1);
731 done:
732 	free(id1);
733 	free(id2);
734 	if (tag1)
735 		got_object_tag_close(tag1);
736 	if (tag2)
737 		got_object_tag_close(tag2);
738 	if (commit1)
739 		got_object_commit_close(commit1);
740 	if (commit2)
741 		got_object_commit_close(commit2);
742 	return err;
743 }
744 
745 const struct got_error *
746 got_ref_cmp_by_commit_timestamp_descending(void *arg, int *cmp,
747     struct got_reference *ref1, struct got_reference *ref2)
748 {
749 	const struct got_error *err;
750 	struct got_repository *repo = arg;
751 	struct got_object_id *id1, *id2 = NULL;
752 	struct got_commit_object *commit1 = NULL, *commit2 = NULL;
753 	time_t time1, time2;
754 
755 	*cmp = 0;
756 
757 	err = got_ref_resolve(&id1, repo, ref1);
758 	if (err)
759 		return err;
760 	err = got_ref_resolve(&id2, repo, ref2);
761 	if (err)
762 		goto done;
763 
764 	err = got_object_open_as_commit(&commit1, repo, id1);
765 	if (err)
766 		goto done;
767 	err = got_object_open_as_commit(&commit2, repo, id2);
768 	if (err)
769 		goto done;
770 	
771 	time1 = got_object_commit_get_committer_time(commit1);
772 	time2 = got_object_commit_get_committer_time(commit2);
773 	if (time1 < time2)
774 		*cmp = 1;
775 	else if (time2 < time1)
776 		*cmp = -1;
777 done:
778 	free(id1);
779 	free(id2);
780 	if (commit1)
781 		got_object_commit_close(commit1);
782 	if (commit2)
783 		got_object_commit_close(commit2);
784 	return err;
785 }
786 
787 static const struct got_error *
788 insert_ref(struct got_reflist_entry **newp, struct got_reflist_head *refs,
789     struct got_reference *ref, struct got_repository *repo,
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 	new = malloc(sizeof(*new));
799 	if (new == NULL)
800 		return got_error_from_errno("malloc");
801 	new->ref = ref;
802 	*newp = new;
803 
804 	/*
805 	 * We must de-duplicate entries on insert because packed-refs may
806 	 * contain redundant entries. On-disk refs take precedence.
807 	 * This code assumes that on-disk revs are read before packed-refs.
808 	 * We're iterating the list anyway, so insert elements sorted by name.
809 	 *
810 	 * Many callers will provide paths in a somewhat sorted order.
811 	 * Iterating backwards from the tail of the list should be more
812 	 * efficient than traversing through the entire list each time
813 	 * an element is inserted.
814 	 */
815 	re = TAILQ_LAST(refs, got_reflist_head);
816 	while (re) {
817 		err = (*cmp_cb)(cmp_arg, &cmp, re->ref, new->ref);
818 		if (err)
819 			return err;
820 		if (cmp == 0) {
821 			/* duplicate */
822 			free(new);
823 			*newp = NULL;
824 			return NULL;
825 		} else if (cmp < 0) {
826 			TAILQ_INSERT_AFTER(refs, re, new, entry);
827 			return NULL;
828 		}
829 		re = TAILQ_PREV(re, got_reflist_head, entry);
830 	}
831 
832 	TAILQ_INSERT_HEAD(refs, new, entry);
833 	return NULL;
834 }
835 
836 static const struct got_error *
837 gather_on_disk_refs(struct got_reflist_head *refs, const char *path_refs,
838     const char *subdir, struct got_repository *repo,
839     got_ref_cmp_cb cmp_cb, void *cmp_arg)
840 {
841 	const struct got_error *err = NULL;
842 	DIR *d = NULL;
843 	char *path_subdir;
844 
845 	while (subdir[0] == '/')
846 		subdir++;
847 
848 	if (asprintf(&path_subdir, "%s/%s", path_refs, subdir) == -1)
849 		return got_error_from_errno("asprintf");
850 
851 	d = opendir(path_subdir);
852 	if (d == NULL)
853 		goto done;
854 
855 	for (;;) {
856 		struct dirent *dent;
857 		struct got_reference *ref;
858 		char *child;
859 		int type;
860 
861 		dent = readdir(d);
862 		if (dent == NULL)
863 			break;
864 
865 		if (strcmp(dent->d_name, ".") == 0 ||
866 		    strcmp(dent->d_name, "..") == 0)
867 			continue;
868 
869 		err = got_path_dirent_type(&type, path_subdir, dent);
870 		if (err)
871 			break;
872 
873 		switch (type) {
874 		case DT_REG:
875 			err = open_ref(&ref, path_refs, subdir, dent->d_name,
876 			    0);
877 			if (err)
878 				goto done;
879 			if (ref) {
880 				struct got_reflist_entry *new;
881 				err = insert_ref(&new, refs, ref, repo,
882 				    cmp_cb, cmp_arg);
883 				if (err || new == NULL /* duplicate */)
884 					got_ref_close(ref);
885 				if (err)
886 					goto done;
887 			}
888 			break;
889 		case DT_DIR:
890 			if (asprintf(&child, "%s%s%s", subdir,
891 			    subdir[0] == '\0' ? "" : "/", dent->d_name) == -1) {
892 				err = got_error_from_errno("asprintf");
893 				break;
894 			}
895 			err = gather_on_disk_refs(refs, path_refs, child, repo,
896 			    cmp_cb, cmp_arg);
897 			free(child);
898 			break;
899 		default:
900 			break;
901 		}
902 	}
903 done:
904 	if (d)
905 		closedir(d);
906 	free(path_subdir);
907 	return err;
908 }
909 
910 const struct got_error *
911 got_ref_list(struct got_reflist_head *refs, struct got_repository *repo,
912     const char *ref_namespace, got_ref_cmp_cb cmp_cb, void *cmp_arg)
913 {
914 	const struct got_error *err;
915 	char *packed_refs_path, *path_refs = NULL;
916 	char *abs_namespace = NULL;
917 	char *buf = NULL, *ondisk_ref_namespace = NULL;
918 	char *line = NULL;
919 	FILE *f = NULL;
920 	struct got_reference *ref;
921 	struct got_reflist_entry *new;
922 
923 	if (ref_namespace == NULL || ref_namespace[0] == '\0') {
924 		path_refs = get_refs_dir_path(repo, GOT_REF_HEAD);
925 		if (path_refs == NULL) {
926 			err = got_error_from_errno("get_refs_dir_path");
927 			goto done;
928 		}
929 		err = open_ref(&ref, path_refs, "", GOT_REF_HEAD, 0);
930 		if (err)
931 			goto done;
932 		err = insert_ref(&new, refs, ref, repo,
933 		    cmp_cb, cmp_arg);
934 		if (err || new == NULL /* duplicate */)
935 			got_ref_close(ref);
936 		if (err && err->code != GOT_ERR_NOT_REF)
937 			goto done;
938 	} else {
939 		/* Try listing a single reference. */
940 		const char *refname = ref_namespace;
941 		path_refs = get_refs_dir_path(repo, refname);
942 		if (path_refs == NULL) {
943 			err = got_error_from_errno("get_refs_dir_path");
944 			goto done;
945 		}
946 		err = open_ref(&ref, path_refs, "", refname, 0);
947 		if (err) {
948 			if (err->code != GOT_ERR_NOT_REF)
949 				goto done;
950 			/* Try to look up references in a given namespace. */
951 		} else {
952 			err = insert_ref(&new, refs, ref, repo,
953 			    cmp_cb, cmp_arg);
954 			if (err || new == NULL /* duplicate */)
955 				got_ref_close(ref);
956 			return err;
957 		}
958 	}
959 
960 	if (ref_namespace) {
961 		size_t len;
962 		/* Canonicalize the path to eliminate double-slashes if any. */
963 		if (asprintf(&abs_namespace, "/%s", ref_namespace) == -1) {
964 			err = got_error_from_errno("asprintf");
965 			goto done;
966 		}
967 		len = strlen(abs_namespace) + 1;
968 		buf = malloc(len);
969 		if (buf == NULL) {
970 			err = got_error_from_errno("malloc");
971 			goto done;
972 		}
973 		err = got_canonpath(abs_namespace, buf, len);
974 		if (err)
975 			goto done;
976 		ondisk_ref_namespace = buf;
977 		while (ondisk_ref_namespace[0] == '/')
978 			ondisk_ref_namespace++;
979 		if (strncmp(ondisk_ref_namespace, "refs/", 5) == 0)
980 			ondisk_ref_namespace += 5;
981 		else if (strcmp(ondisk_ref_namespace, "refs") == 0)
982 			ondisk_ref_namespace = "";
983 	}
984 
985 	/* Gather on-disk refs before parsing packed-refs. */
986 	free(path_refs);
987 	path_refs = get_refs_dir_path(repo, "");
988 	if (path_refs == NULL) {
989 		err = got_error_from_errno("get_refs_dir_path");
990 		goto done;
991 	}
992 	err = gather_on_disk_refs(refs, path_refs,
993 	    ondisk_ref_namespace ? ondisk_ref_namespace : "", repo,
994 	    cmp_cb, cmp_arg);
995 	if (err)
996 		goto done;
997 
998 	/*
999 	 * The packed-refs file may contain redundant entries, in which
1000 	 * case on-disk refs take precedence.
1001 	 */
1002 	packed_refs_path = got_repo_get_path_packed_refs(repo);
1003 	if (packed_refs_path == NULL) {
1004 		err = got_error_from_errno("got_repo_get_path_packed_refs");
1005 		goto done;
1006 	}
1007 
1008 	f = fopen(packed_refs_path, "r");
1009 	free(packed_refs_path);
1010 	if (f) {
1011 		size_t linesize = 0;
1012 		ssize_t linelen;
1013 		for (;;) {
1014 			linelen = getline(&line, &linesize, f);
1015 			if (linelen == -1) {
1016 				if (feof(f))
1017 					break;
1018 				err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
1019 				goto done;
1020 			}
1021 			if (linelen > 0 && line[linelen - 1] == '\n')
1022 				line[linelen - 1] = '\0';
1023 			err = parse_packed_ref_line(&ref, NULL, line);
1024 			if (err)
1025 				goto done;
1026 			if (ref) {
1027 				if (ref_namespace) {
1028 					const char *name;
1029 					name = got_ref_get_name(ref);
1030 					if (!got_path_is_child(name,
1031 					    ref_namespace,
1032 					    strlen(ref_namespace))) {
1033 						got_ref_close(ref);
1034 						continue;
1035 					}
1036 				}
1037 				err = insert_ref(&new, refs, ref, repo,
1038 				    cmp_cb, cmp_arg);
1039 				if (err || new == NULL /* duplicate */)
1040 					got_ref_close(ref);
1041 				if (err)
1042 					goto done;
1043 			}
1044 		}
1045 	}
1046 done:
1047 	free(abs_namespace);
1048 	free(buf);
1049 	free(line);
1050 	free(path_refs);
1051 	if (f && fclose(f) == EOF && err == NULL)
1052 		err = got_error_from_errno("fclose");
1053 	return err;
1054 }
1055 
1056 void
1057 got_ref_list_free(struct got_reflist_head *refs)
1058 {
1059 	struct got_reflist_entry *re;
1060 
1061 	while ((re = TAILQ_FIRST(refs))) {
1062 		TAILQ_REMOVE(refs, re, entry);
1063 		free(re);
1064 	}
1065 
1066 }
1067 
1068 int
1069 got_ref_is_symbolic(struct got_reference *ref)
1070 {
1071 	return (ref->flags & GOT_REF_IS_SYMBOLIC);
1072 }
1073 
1074 const struct got_error *
1075 got_ref_change_ref(struct got_reference *ref, struct got_object_id *id)
1076 {
1077 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
1078 		return got_error(GOT_ERR_BAD_REF_TYPE);
1079 
1080 	memcpy(ref->ref.ref.sha1, id->sha1, sizeof(ref->ref.ref.sha1));
1081 	return NULL;
1082 }
1083 
1084 const struct got_error *
1085 got_ref_change_symref(struct got_reference *ref, const char *refname)
1086 {
1087 	char *new_name;
1088 
1089 	if ((ref->flags & GOT_REF_IS_SYMBOLIC) == 0)
1090 		return got_error(GOT_ERR_BAD_REF_TYPE);
1091 
1092 	new_name = strdup(refname);
1093 	if (new_name == NULL)
1094 		return got_error_from_errno("strdup");
1095 
1096 	free(ref->ref.symref.ref);
1097 	ref->ref.symref.ref = new_name;
1098 	return NULL;
1099 }
1100 
1101 const struct got_error *
1102 got_ref_change_symref_to_ref(struct got_reference *symref,
1103     struct got_object_id *id)
1104 {
1105 	if ((symref->flags & GOT_REF_IS_SYMBOLIC) == 0)
1106 		return got_error(GOT_ERR_BAD_REF_TYPE);
1107 
1108 	symref->ref.ref.name = symref->ref.symref.name;
1109 	memcpy(symref->ref.ref.sha1, id->sha1, SHA1_DIGEST_LENGTH);
1110 	symref->flags &= ~GOT_REF_IS_SYMBOLIC;
1111 	return NULL;
1112 }
1113 
1114 const struct got_error *
1115 got_ref_write(struct got_reference *ref, struct got_repository *repo)
1116 {
1117 	const struct got_error *err = NULL, *unlock_err = NULL;
1118 	const char *name = got_ref_get_name(ref);
1119 	char *path_refs = NULL, *path = NULL, *tmppath = NULL;
1120 	struct got_lockfile *lf = NULL;
1121 	FILE *f = NULL;
1122 	size_t n;
1123 	struct stat sb;
1124 
1125 	path_refs = get_refs_dir_path(repo, name);
1126 	if (path_refs == NULL) {
1127 		err = got_error_from_errno2("get_refs_dir_path", name);
1128 		goto done;
1129 	}
1130 
1131 	if (asprintf(&path, "%s/%s", path_refs, name) == -1) {
1132 		err = got_error_from_errno("asprintf");
1133 		goto done;
1134 	}
1135 
1136 	err = got_opentemp_named(&tmppath, &f, path);
1137 	if (err) {
1138 		char *parent;
1139 		if (!(err->code == GOT_ERR_ERRNO && errno == ENOENT))
1140 			goto done;
1141 		err = got_path_dirname(&parent, path);
1142 		if (err)
1143 			goto done;
1144 		err = got_path_mkdir(parent);
1145 		free(parent);
1146 		if (err)
1147 			goto done;
1148 		err = got_opentemp_named(&tmppath, &f, path);
1149 		if (err)
1150 			goto done;
1151 	}
1152 
1153 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
1154 		n = fprintf(f, "ref: %s\n", ref->ref.symref.ref);
1155 		if (n != strlen(ref->ref.symref.ref) + 6) {
1156 			err = got_ferror(f, GOT_ERR_IO);
1157 			goto done;
1158 		}
1159 	} else {
1160 		char hex[SHA1_DIGEST_STRING_LENGTH];
1161 		if (got_sha1_digest_to_str(ref->ref.ref.sha1, hex,
1162 		    sizeof(hex)) == NULL) {
1163 			err = got_error(GOT_ERR_BAD_REF_DATA);
1164 			goto done;
1165 		}
1166 		n = fprintf(f, "%s\n", hex);
1167 		if (n != sizeof(hex)) {
1168 			err = got_ferror(f, GOT_ERR_IO);
1169 			goto done;
1170 		}
1171 	}
1172 
1173 	if (ref->lf == NULL) {
1174 		err = got_lockfile_lock(&lf, path);
1175 		if (err)
1176 			goto done;
1177 	}
1178 
1179 	/* XXX: check if old content matches our expectations? */
1180 
1181 	if (stat(path, &sb) != 0) {
1182 		if (errno != ENOENT) {
1183 			err = got_error_from_errno2("stat", path);
1184 			goto done;
1185 		}
1186 		sb.st_mode = GOT_DEFAULT_FILE_MODE;
1187 	}
1188 
1189 	if (fchmod(fileno(f), sb.st_mode) != 0) {
1190 		err = got_error_from_errno2("fchmod", tmppath);
1191 		goto done;
1192 	}
1193 
1194 	if (rename(tmppath, path) != 0) {
1195 		err = got_error_from_errno3("rename", tmppath, path);
1196 		goto done;
1197 	}
1198 	free(tmppath);
1199 	tmppath = NULL;
1200 done:
1201 	if (ref->lf == NULL && lf)
1202 		unlock_err = got_lockfile_unlock(lf);
1203 	if (f) {
1204 		if (fclose(f) == EOF && err == NULL)
1205 			err = got_error_from_errno("fclose");
1206 	}
1207 	free(path_refs);
1208 	free(path);
1209 	if (tmppath) {
1210 		if (unlink(tmppath) != 0 && err == NULL)
1211 			err = got_error_from_errno2("unlink", tmppath);
1212 		free(tmppath);
1213 	}
1214 	return err ? err : unlock_err;
1215 }
1216 
1217 static const struct got_error *
1218 delete_packed_ref(struct got_reference *delref, struct got_repository *repo)
1219 {
1220 	const struct got_error *err = NULL, *unlock_err = NULL;
1221 	struct got_lockfile *lf = NULL;
1222 	FILE *f = NULL, *tmpf = NULL;
1223 	char *line = NULL, *packed_refs_path, *tmppath = NULL;
1224 	size_t linesize = 0;
1225 	struct got_reflist_head refs;
1226 	int found_delref = 0;
1227 
1228 	/* The packed-refs file does not cotain symbolic references. */
1229 	if (delref->flags & GOT_REF_IS_SYMBOLIC)
1230 		return got_error(GOT_ERR_BAD_REF_DATA);
1231 
1232 	TAILQ_INIT(&refs);
1233 
1234 	packed_refs_path = got_repo_get_path_packed_refs(repo);
1235 	if (packed_refs_path == NULL)
1236 		return got_error_from_errno("got_repo_get_path_packed_refs");
1237 
1238 	err = got_opentemp_named(&tmppath, &tmpf, packed_refs_path);
1239 	if (err)
1240 		goto done;
1241 
1242 	if (delref->lf == NULL) {
1243 		err = got_lockfile_lock(&lf, packed_refs_path);
1244 		if (err)
1245 			goto done;
1246 	}
1247 
1248 	f = fopen(packed_refs_path, "r");
1249 	if (f == NULL) {
1250 		err = got_error_from_errno2("fopen", packed_refs_path);
1251 		goto done;
1252 	}
1253 	for (;;) {
1254 		ssize_t linelen;
1255 		struct got_reference *ref;
1256 		struct got_reflist_entry *new;
1257 
1258 		linelen = getline(&line, &linesize, f);
1259 		if (linelen == -1) {
1260 			if (feof(f))
1261 				break;
1262 			err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
1263 			goto done;
1264 		}
1265 		if (linelen > 0 && line[linelen - 1] == '\n')
1266 			line[linelen - 1] = '\0';
1267 		err = parse_packed_ref_line(&ref, NULL, line);
1268 		if (err)
1269 			goto done;
1270 		if (ref == NULL)
1271 			continue;
1272 
1273 		if (strcmp(ref->ref.ref.name, delref->ref.ref.name) == 0 &&
1274 		    memcmp(ref->ref.ref.sha1, delref->ref.ref.sha1,
1275 		    sizeof(delref->ref.ref.sha1)) == 0) {
1276 			found_delref = 1;
1277 			got_ref_close(ref);
1278 			continue;
1279 		}
1280 
1281 		err = insert_ref(&new, &refs, ref, repo,
1282 		    got_ref_cmp_by_name, NULL);
1283 		if (err || new == NULL /* duplicate */)
1284 			got_ref_close(ref);
1285 		if (err)
1286 			goto done;
1287 	}
1288 
1289 	if (found_delref) {
1290 		struct got_reflist_entry *re;
1291 		size_t n;
1292 		struct stat sb;
1293 
1294 		n = fprintf(tmpf, "%s\n", GOT_PACKED_REFS_HEADER);
1295 		if (n != sizeof(GOT_PACKED_REFS_HEADER)) {
1296 			err = got_ferror(f, GOT_ERR_IO);
1297 			goto done;
1298 		}
1299 
1300 		TAILQ_FOREACH(re, &refs, entry) {
1301 			uint8_t hex[SHA1_DIGEST_STRING_LENGTH];
1302 
1303 			if (got_sha1_digest_to_str(re->ref->ref.ref.sha1, hex,
1304 			    sizeof(hex)) == NULL) {
1305 				err = got_error(GOT_ERR_BAD_REF_DATA);
1306 				goto done;
1307 			}
1308 			n = fprintf(tmpf, "%s ", hex);
1309 			if (n != sizeof(hex)) {
1310 				err = got_ferror(f, GOT_ERR_IO);
1311 				goto done;
1312 			}
1313 			n = fprintf(tmpf, "%s\n", re->ref->ref.ref.name);
1314 			if (n != strlen(re->ref->ref.ref.name) + 1) {
1315 				err = got_ferror(f, GOT_ERR_IO);
1316 				goto done;
1317 			}
1318 		}
1319 
1320 		if (fflush(tmpf) != 0) {
1321 			err = got_error_from_errno("fflush");
1322 			goto done;
1323 		}
1324 
1325 		if (fstat(fileno(f), &sb) != 0) {
1326 			if (errno != ENOENT) {
1327 				err = got_error_from_errno2("fstat",
1328 				    packed_refs_path);
1329 				goto done;
1330 			}
1331 			sb.st_mode = GOT_DEFAULT_FILE_MODE;
1332 		}
1333 
1334 		if (fchmod(fileno(tmpf), sb.st_mode) != 0) {
1335 			err = got_error_from_errno2("fchmod", tmppath);
1336 			goto done;
1337 		}
1338 
1339 		if (rename(tmppath, packed_refs_path) != 0) {
1340 			err = got_error_from_errno3("rename", tmppath,
1341 			    packed_refs_path);
1342 			goto done;
1343 		}
1344 	}
1345 done:
1346 	if (delref->lf == NULL && lf)
1347 		unlock_err = got_lockfile_unlock(lf);
1348 	if (f) {
1349 		if (fclose(f) == EOF && err == NULL)
1350 			err = got_error_from_errno("fclose");
1351 	}
1352 	if (tmpf) {
1353 		unlink(tmppath);
1354 		if (fclose(tmpf) == EOF && err == NULL)
1355 			err = got_error_from_errno("fclose");
1356 	}
1357 	free(tmppath);
1358 	free(packed_refs_path);
1359 	free(line);
1360 	got_ref_list_free(&refs);
1361 	return err ? err : unlock_err;
1362 }
1363 
1364 static const struct got_error *
1365 delete_loose_ref(struct got_reference *ref, struct got_repository *repo)
1366 {
1367 	const struct got_error *err = NULL, *unlock_err = NULL;
1368 	const char *name = got_ref_get_name(ref);
1369 	char *path_refs = NULL, *path = NULL;
1370 	struct got_lockfile *lf = NULL;
1371 
1372 	path_refs = get_refs_dir_path(repo, name);
1373 	if (path_refs == NULL) {
1374 		err = got_error_from_errno2("get_refs_dir_path", name);
1375 		goto done;
1376 	}
1377 
1378 	if (asprintf(&path, "%s/%s", path_refs, name) == -1) {
1379 		err = got_error_from_errno("asprintf");
1380 		goto done;
1381 	}
1382 
1383 	if (ref->lf == NULL) {
1384 		err = got_lockfile_lock(&lf, path);
1385 		if (err)
1386 			goto done;
1387 	}
1388 
1389 	/* XXX: check if old content matches our expectations? */
1390 
1391 	if (unlink(path) != 0)
1392 		err = got_error_from_errno2("unlink", path);
1393 done:
1394 	if (ref->lf == NULL && lf)
1395 		unlock_err = got_lockfile_unlock(lf);
1396 
1397 	free(path_refs);
1398 	free(path);
1399 	return err ? err : unlock_err;
1400 }
1401 
1402 const struct got_error *
1403 got_ref_delete(struct got_reference *ref, struct got_repository *repo)
1404 {
1405 	const struct got_error *err = NULL;
1406 	struct got_reference *ref2;
1407 
1408 	if (ref->flags & GOT_REF_IS_PACKED) {
1409 		err = delete_packed_ref(ref, repo);
1410 		if (err)
1411 			return err;
1412 
1413 		err = got_ref_open(&ref2, repo, got_ref_get_name(ref), 0);
1414 		if (err) {
1415 			if (err->code == GOT_ERR_NOT_REF)
1416 				return NULL;
1417 			return err;
1418 		}
1419 
1420 		err = delete_loose_ref(ref2, repo);
1421 		got_ref_close(ref2);
1422 		return err;
1423 	} else {
1424 		err = delete_loose_ref(ref, repo);
1425 		if (err)
1426 			return err;
1427 
1428 		err = got_ref_open(&ref2, repo, got_ref_get_name(ref), 0);
1429 		if (err) {
1430 			if (err->code == GOT_ERR_NOT_REF)
1431 				return NULL;
1432 			return err;
1433 		}
1434 
1435 		err = delete_packed_ref(ref2, repo);
1436 		got_ref_close(ref2);
1437 		return err;
1438 	}
1439 }
1440 
1441 const struct got_error *
1442 got_ref_unlock(struct got_reference *ref)
1443 {
1444 	const struct got_error *err;
1445 	err = got_lockfile_unlock(ref->lf);
1446 	ref->lf = NULL;
1447 	return err;
1448 }
1449 
1450 struct got_reflist_object_id_map {
1451 	struct got_object_idset *idset;
1452 };
1453 
1454 struct got_reflist_object_id_map_entry {
1455 	struct got_reflist_head refs;
1456 };
1457 
1458 static const struct got_error *
1459 add_object_id_map_entry(struct got_object_idset *idset,
1460     struct got_object_id *id, struct got_reflist_entry *re)
1461 {
1462 	const struct got_error *err = NULL;
1463 	struct got_reflist_object_id_map_entry *ent;
1464 	struct got_reflist_entry *new;
1465 
1466 	ent = got_object_idset_get(idset, id);
1467 	if (ent == NULL) {
1468 		ent = malloc(sizeof(*ent));
1469 		if (ent == NULL)
1470 			return got_error_from_errno("malloc");
1471 
1472 		TAILQ_INIT(&ent->refs);
1473 		err = got_object_idset_add(idset, id, ent);
1474 		if (err)
1475 			return err;
1476 	}
1477 
1478 	err = got_reflist_entry_dup(&new, re);
1479 	if (err)
1480 		return err;
1481 
1482 	TAILQ_INSERT_TAIL(&ent->refs, new, entry);
1483 	return NULL;
1484 }
1485 
1486 const struct got_error *
1487 got_reflist_object_id_map_create(struct got_reflist_object_id_map **map,
1488     struct got_reflist_head *refs, struct got_repository *repo)
1489 {
1490 	const struct got_error *err = NULL;
1491 	struct got_object_idset *idset;
1492 	struct got_object_id *id = NULL;
1493 	struct got_reflist_entry *re;
1494 
1495 	idset = got_object_idset_alloc();
1496 	if (idset == NULL)
1497 		return got_error_from_errno("got_object_idset_alloc");
1498 
1499 	*map = malloc(sizeof(**map));
1500 	if (*map == NULL) {
1501 		got_object_idset_free(idset);
1502 		return got_error_from_errno("malloc");
1503 	}
1504 	(*map)->idset = idset;
1505 
1506 	TAILQ_FOREACH(re, refs, entry) {
1507 		struct got_tag_object *tag = NULL;
1508 
1509 		err = got_ref_resolve(&id, repo, re->ref);
1510 		if (err)
1511 			goto done;
1512 
1513 		err = add_object_id_map_entry(idset, id, re);
1514 		if (err)
1515 			goto done;
1516 
1517 		if (strstr(got_ref_get_name(re->ref), "/tags/") == NULL) {
1518 			free(id);
1519 			id = NULL;
1520 			continue;
1521 		}
1522 
1523 		err = got_object_open_as_tag(&tag, repo, id);
1524 		if (err) {
1525 			if (err->code != GOT_ERR_OBJ_TYPE)
1526 				goto done;
1527 			/* Ref points at something other than a tag. */
1528 			err = NULL;
1529 			tag = NULL;
1530 			free(id);
1531 			id = NULL;
1532 			continue;
1533 		}
1534 
1535 		err = add_object_id_map_entry(idset,
1536 		    got_object_tag_get_object_id(tag), re);
1537 		got_object_tag_close(tag);
1538 		if (err)
1539 			goto done;
1540 
1541 		free(id);
1542 		id = NULL;
1543 	}
1544 done:
1545 	free(id);
1546 	if (err) {
1547 		got_reflist_object_id_map_free(*map);
1548 		*map = NULL;
1549 	}
1550 	return err;
1551 }
1552 
1553 struct got_reflist_head *
1554 got_reflist_object_id_map_lookup(struct got_reflist_object_id_map *map,
1555     struct got_object_id *id)
1556 {
1557 	struct got_reflist_object_id_map_entry *ent;
1558 	ent = got_object_idset_get(map->idset, id);
1559 	if (ent)
1560 		return &ent->refs;
1561 	return NULL;
1562 }
1563 
1564 static const struct got_error *
1565 free_id_map_entry(struct got_object_id *id, void *data, void *arg)
1566 {
1567 	struct got_reflist_object_id_map_entry *ent = data;
1568 
1569 	got_ref_list_free(&ent->refs);
1570 	free(ent);
1571 	return NULL;
1572 }
1573 
1574 void
1575 got_reflist_object_id_map_free(struct got_reflist_object_id_map *map)
1576 {
1577 	got_object_idset_for_each(map->idset, free_id_map_entry, NULL);
1578 	got_object_idset_free(map->idset);
1579 	free(map);
1580 }