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Date:: Thu Feb 23 08:41:30 2023 UTC
Message:: rename lib/sha1.c to lib/hash.c It will soon grow functions to deal with sha256 too. stsp@ agrees.
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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 <sha2.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_hash.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 	struct got_object_id id;
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 	time_t mtime;
91 
92 	/* Cached timestamp for got_ref_cmp_by_commit_timestamp_descending() */
93 	time_t committer_time;
94 };
95 
96 static const struct got_error *
97 alloc_ref(struct got_reference **ref, const char *name,
98     struct got_object_id *id, int flags, time_t mtime)
99 {
100 	const struct got_error *err = NULL;
101 
102 	*ref = calloc(1, sizeof(**ref));
103 	if (*ref == NULL)
104 		return got_error_from_errno("calloc");
105 
106 	memcpy(&(*ref)->ref.ref.id, id, sizeof((*ref)->ref.ref.id));
107 	(*ref)->flags = flags;
108 	(*ref)->ref.ref.name = strdup(name);
109 	(*ref)->mtime = mtime;
110 	if ((*ref)->ref.ref.name == NULL) {
111 		err = got_error_from_errno("strdup");
112 		got_ref_close(*ref);
113 		*ref = NULL;
114 	}
115 	return err;
116 }
117 
118 static const struct got_error *
119 alloc_symref(struct got_reference **ref, const char *name,
120     const char *target_ref, int flags)
121 {
122 	const struct got_error *err = NULL;
123 
124 	*ref = calloc(1, sizeof(**ref));
125 	if (*ref == NULL)
126 		return got_error_from_errno("calloc");
127 
128 	(*ref)->flags = GOT_REF_IS_SYMBOLIC | flags;
129 	(*ref)->ref.symref.name = strdup(name);
130 	if ((*ref)->ref.symref.name == NULL) {
131 		err = got_error_from_errno("strdup");
132 		got_ref_close(*ref);
133 		*ref = NULL;
134 		return err;
135 	}
136 	(*ref)->ref.symref.ref = strdup(target_ref);
137 	if ((*ref)->ref.symref.ref == NULL) {
138 		err = got_error_from_errno("strdup");
139 		got_ref_close(*ref);
140 		*ref = NULL;
141 	}
142 	return err;
143 }
144 
145 static const struct got_error *
146 parse_symref(struct got_reference **ref, const char *name, const char *line)
147 {
148 	if (line[0] == '\0')
149 		return got_error(GOT_ERR_BAD_REF_DATA);
150 
151 	return alloc_symref(ref, name, line, 0);
152 }
153 
154 static const struct got_error *
155 parse_ref_line(struct got_reference **ref, const char *name, const char *line,
156     time_t mtime)
157 {
158 	struct got_object_id id;
159 
160 	if (strncmp(line, "ref: ", 5) == 0) {
161 		line += 5;
162 		return parse_symref(ref, name, line);
163 	}
164 
165 	if (!got_parse_sha1_digest(id.sha1, line))
166 		return got_error(GOT_ERR_BAD_REF_DATA);
167 
168 	return alloc_ref(ref, name, &id, 0, mtime);
169 }
170 
171 static const struct got_error *
172 parse_ref_file(struct got_reference **ref, const char *name,
173     const char *absname, const char *abspath, int lock)
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);
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)
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_sha1_digest(id.sha1, line))
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 {
320 	const struct got_error *err = NULL;
321 	char *abs_refname;
322 	char *line = NULL;
323 	size_t linesize = 0;
324 	ssize_t linelen;
325 	int i, ref_is_absolute = (strncmp(refname, "refs/", 5) == 0);
326 
327 	*ref = NULL;
328 
329 	if (ref_is_absolute)
330 		abs_refname = (char *)refname;
331 	do {
332 		linelen = getline(&line, &linesize, f);
333 		if (linelen == -1) {
334 			if (feof(f))
335 				break;
336 			err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
337 			break;
338 		}
339 		if (linelen > 0 && line[linelen - 1] == '\n')
340 			line[linelen - 1] = '\0';
341 		for (i = 0; i < nsubdirs; i++) {
342 			if (!ref_is_absolute &&
343 			    asprintf(&abs_refname, "refs/%s/%s", subdirs[i],
344 			    refname) == -1)
345 				return got_error_from_errno("asprintf");
346 			err = parse_packed_ref_line(ref, abs_refname, line,
347 			    mtime);
348 			if (!ref_is_absolute)
349 				free(abs_refname);
350 			if (err || *ref != NULL)
351 				break;
352 		}
353 		if (err)
354 			break;
355 	} while (*ref == NULL);
356 	free(line);
357 
358 	return err;
359 }
360 
361 static const struct got_error *
362 open_ref(struct got_reference **ref, const char *path_refs, const char *subdir,
363     const char *name, int lock)
364 {
365 	const struct got_error *err = NULL;
366 	char *path = NULL;
367 	char *absname = NULL;
368 	int ref_is_absolute = (strncmp(name, "refs/", 5) == 0);
369 	int ref_is_well_known = (subdir[0] == '\0' && is_well_known_ref(name));
370 
371 	*ref = NULL;
372 
373 	if (!got_ref_name_is_valid(name))
374 		return got_error_path(name, GOT_ERR_BAD_REF_NAME);
375 
376 	if (ref_is_absolute || ref_is_well_known) {
377 		if (asprintf(&path, "%s/%s", path_refs, name) == -1)
378 			return got_error_from_errno("asprintf");
379 		absname = (char *)name;
380 	} else {
381 		if (asprintf(&path, "%s/%s%s%s", path_refs, subdir,
382 		    subdir[0] ? "/" : "", name) == -1)
383 			return got_error_from_errno("asprintf");
384 
385 		if (asprintf(&absname, "refs/%s%s%s",
386 		    subdir, subdir[0] ? "/" : "", name) == -1) {
387 			err = got_error_from_errno("asprintf");
388 			goto done;
389 		}
390 	}
391 
392 	err = parse_ref_file(ref, name, absname, path, lock);
393 done:
394 	if (!ref_is_absolute && !ref_is_well_known)
395 		free(absname);
396 	free(path);
397 	return err;
398 }
399 
400 const struct got_error *
401 got_ref_open(struct got_reference **ref, struct got_repository *repo,
402     const char *refname, int lock)
403 {
404 	const struct got_error *err = NULL;
405 	char *packed_refs_path = NULL, *path_refs = NULL;
406 	const char *subdirs[] = {
407 	    GOT_REF_HEADS, GOT_REF_TAGS, GOT_REF_REMOTES
408 	};
409 	size_t i;
410 	int well_known = is_well_known_ref(refname);
411 	struct got_lockfile *lf = NULL;
412 
413 	*ref = NULL;
414 
415 	path_refs = get_refs_dir_path(repo, refname);
416 	if (path_refs == NULL) {
417 		err = got_error_from_errno2("get_refs_dir_path", refname);
418 		goto done;
419 	}
420 
421 	if (well_known) {
422 		err = open_ref(ref, path_refs, "", refname, lock);
423 	} else {
424 		FILE *f;
425 
426 		/* Search on-disk refs before packed refs! */
427 		for (i = 0; i < nitems(subdirs); i++) {
428 			err = open_ref(ref, path_refs, subdirs[i], refname,
429 			    lock);
430 			if ((err && err->code != GOT_ERR_NOT_REF) || *ref)
431 				goto done;
432 		}
433 
434 		packed_refs_path = got_repo_get_path_packed_refs(repo);
435 		if (packed_refs_path == NULL) {
436 			err = got_error_from_errno(
437 			    "got_repo_get_path_packed_refs");
438 			goto done;
439 		}
440 
441 		if (lock) {
442 			err = got_lockfile_lock(&lf, packed_refs_path, -1);
443 			if (err)
444 				goto done;
445 		}
446 		f = fopen(packed_refs_path, "rbe");
447 		if (f != NULL) {
448 			struct stat sb;
449 			if (fstat(fileno(f), &sb) == -1) {
450 				err = got_error_from_errno2("fstat",
451 				    packed_refs_path);
452 				goto done;
453 			}
454 			err = open_packed_ref(ref, f, subdirs, nitems(subdirs),
455 			    refname, sb.st_mtime);
456 			if (!err) {
457 				if (fclose(f) == EOF) {
458 					err = got_error_from_errno("fclose");
459 					got_ref_close(*ref);
460 					*ref = NULL;
461 				} else if (*ref)
462 					(*ref)->lf = lf;
463 			}
464 		}
465 	}
466 done:
467 	if (!err && *ref == NULL)
468 		err = got_error_not_ref(refname);
469 	if (err && lf)
470 		got_lockfile_unlock(lf, -1);
471 	free(packed_refs_path);
472 	free(path_refs);
473 	return err;
474 }
475 
476 void
477 got_ref_close(struct got_reference *ref)
478 {
479 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
480 		free(ref->ref.symref.name);
481 		free(ref->ref.symref.ref);
482 	} else
483 		free(ref->ref.ref.name);
484 	free(ref);
485 }
486 
487 struct got_reference *
488 got_ref_dup(struct got_reference *ref)
489 {
490 	struct got_reference *ret;
491 
492 	ret = calloc(1, sizeof(*ret));
493 	if (ret == NULL)
494 		return NULL;
495 
496 	ret->flags = ref->flags;
497 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
498 		ret->ref.symref.name = strdup(ref->ref.symref.name);
499 		if (ret->ref.symref.name == NULL) {
500 			free(ret);
501 			return NULL;
502 		}
503 		ret->ref.symref.ref = strdup(ref->ref.symref.ref);
504 		if (ret->ref.symref.ref == NULL) {
505 			free(ret->ref.symref.name);
506 			free(ret);
507 			return NULL;
508 		}
509 	} else {
510 		ret->ref.ref.name = strdup(ref->ref.ref.name);
511 		if (ret->ref.ref.name == NULL) {
512 			free(ret);
513 			return NULL;
514 		}
515 		memcpy(&ret->ref.ref.id, &ref->ref.ref.id,
516 		    sizeof(ret->ref.ref.id));
517 	}
518 
519 	return ret;
520 }
521 
522 const struct got_error *
523 got_reflist_entry_dup(struct got_reflist_entry **newp,
524     struct got_reflist_entry *re)
525 {
526 	const struct got_error *err = NULL;
527 	struct got_reflist_entry *new;
528 
529 	*newp = NULL;
530 
531 	new = malloc(sizeof(*new));
532 	if (new == NULL)
533 		return got_error_from_errno("malloc");
534 
535 	new->ref = got_ref_dup(re->ref);
536 	if (new->ref == NULL) {
537 		err = got_error_from_errno("got_ref_dup");
538 		free(new);
539 		return err;
540 	}
541 
542 	*newp = new;
543 	return NULL;
544 }
545 
546 const struct got_error *
547 got_ref_resolve_symbolic(struct got_reference **resolved,
548     struct got_repository *repo, struct got_reference *ref)
549 {
550 	struct got_reference *nextref;
551 	const struct got_error *err;
552 
553 	err = got_ref_open(&nextref, repo, ref->ref.symref.ref, 0);
554 	if (err)
555 		return err;
556 
557 	if (nextref->flags & GOT_REF_IS_SYMBOLIC)
558 		err = got_ref_resolve_symbolic(resolved, repo, nextref);
559 	else
560 		*resolved = got_ref_dup(nextref);
561 
562 	got_ref_close(nextref);
563 	return err;
564 }
565 
566 static const struct got_error *
567 ref_resolve(struct got_object_id **id, struct got_repository *repo,
568     struct got_reference *ref, int recursion)
569 {
570 	const struct got_error *err;
571 
572 	if (recursion <= 0)
573 		return got_error_msg(GOT_ERR_RECURSION,
574 		    "reference recursion limit reached");
575 
576 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
577 		struct got_reference *resolved = NULL;
578 		err = got_ref_resolve_symbolic(&resolved, repo, ref);
579 		if (err == NULL)
580 			err = ref_resolve(id, repo, resolved, --recursion);
581 		if (resolved)
582 			got_ref_close(resolved);
583 		return err;
584 	}
585 
586 	*id = calloc(1, sizeof(**id));
587 	if (*id == NULL)
588 		return got_error_from_errno("calloc");
589 	memcpy(*id, &ref->ref.ref.id, sizeof(**id));
590 	return NULL;
591 }
592 
593 const struct got_error *
594 got_ref_resolve(struct got_object_id **id, struct got_repository *repo,
595     struct got_reference *ref)
596 {
597 	return ref_resolve(id, repo, ref, GOT_REF_RECURSE_MAX);
598 }
599 
600 char *
601 got_ref_to_str(struct got_reference *ref)
602 {
603 	char *str;
604 
605 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
606 		return strdup(ref->ref.symref.ref);
607 
608 	if (got_object_id_str(&str, &ref->ref.ref.id) != NULL)
609 		return NULL;
610 
611 	return str;
612 }
613 
614 const char *
615 got_ref_get_name(struct got_reference *ref)
616 {
617 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
618 		return ref->ref.symref.name;
619 
620 	return ref->ref.ref.name;
621 }
622 
623 const char *
624 got_ref_get_symref_target(struct got_reference *ref)
625 {
626 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
627 		return ref->ref.symref.ref;
628 
629 	return NULL;
630 }
631 
632 time_t
633 got_ref_get_mtime(struct got_reference *ref)
634 {
635 	return ref->mtime;
636 }
637 
638 const struct got_error *
639 got_ref_cmp_by_name(void *arg, int *cmp, struct got_reference *re1,
640     struct got_reference* re2)
641 {
642 	const char *name1 = got_ref_get_name(re1);
643 	const char *name2 = got_ref_get_name(re2);
644 
645 	*cmp = got_path_cmp(name1, name2, strlen(name1), strlen(name2));
646 	return NULL;
647 }
648 
649 const struct got_error *
650 got_ref_cmp_tags(void *arg, int *cmp, struct got_reference *ref1,
651     struct got_reference *ref2)
652 {
653 	const struct got_error *err = NULL;
654 	struct got_repository *repo = arg;
655 	struct got_object_id *id1, *id2 = NULL;
656 	struct got_tag_object *tag1 = NULL, *tag2 = NULL;
657 	struct got_commit_object *commit1 = NULL, *commit2 = NULL;
658 	time_t time1, time2;
659 
660 	*cmp = 0;
661 
662 	err = got_ref_resolve(&id1, repo, ref1);
663 	if (err)
664 		return err;
665 	err = got_object_open_as_tag(&tag1, repo, id1);
666 	if (err) {
667 		if (err->code != GOT_ERR_OBJ_TYPE)
668 			goto done;
669 		/* "lightweight" tag */
670 		err = got_object_open_as_commit(&commit1, repo, id1);
671 		if (err)
672 			goto done;
673 		time1 = got_object_commit_get_committer_time(commit1);
674 	} else
675 		time1 = got_object_tag_get_tagger_time(tag1);
676 
677 	err = got_ref_resolve(&id2, repo, ref2);
678 	if (err)
679 		goto done;
680 	err = got_object_open_as_tag(&tag2, repo, id2);
681 	if (err) {
682 		if (err->code != GOT_ERR_OBJ_TYPE)
683 			goto done;
684 		/* "lightweight" tag */
685 		err = got_object_open_as_commit(&commit2, repo, id2);
686 		if (err)
687 			goto done;
688 		time2 = got_object_commit_get_committer_time(commit2);
689 	} else
690 		time2 = got_object_tag_get_tagger_time(tag2);
691 
692 	/* Put latest tags first. */
693 	if (time1 < time2)
694 		*cmp = 1;
695 	else if (time1 > time2)
696 		*cmp = -1;
697 	else
698 		err = got_ref_cmp_by_name(NULL, cmp, ref2, ref1);
699 done:
700 	free(id1);
701 	free(id2);
702 	if (tag1)
703 		got_object_tag_close(tag1);
704 	if (tag2)
705 		got_object_tag_close(tag2);
706 	if (commit1)
707 		got_object_commit_close(commit1);
708 	if (commit2)
709 		got_object_commit_close(commit2);
710 	return err;
711 }
712 
713 static const struct got_error *
714 get_committer_time(struct got_reference *ref, struct got_repository *repo)
715 {
716 	const struct got_error *err = NULL;
717 	int obj_type;
718 	struct got_commit_object *commit = NULL;
719 	struct got_tag_object *tag = NULL;
720 	struct got_object_id *id = NULL;
721 
722 	err = got_ref_resolve(&id, repo, ref);
723 	if (err)
724 		return err;
725 
726 	err = got_object_get_type(&obj_type, repo, id);
727 	if (err)
728 		goto done;
729 
730 	switch (obj_type) {
731 	case GOT_OBJ_TYPE_COMMIT:
732 		err = got_object_open_as_commit(&commit, repo, id);
733 		if (err)
734 			goto done;
735 		ref->committer_time =
736 		    got_object_commit_get_committer_time(commit);
737 		break;
738 	case GOT_OBJ_TYPE_TAG:
739 		err = got_object_open_as_tag(&tag, repo, id);
740 		if (err)
741 			goto done;
742 		ref->committer_time = got_object_tag_get_tagger_time(tag);
743 		break;
744 	default:
745 		/* best effort for other object types */
746 		ref->committer_time = got_ref_get_mtime(ref);
747 		break;
748 	}
749 done:
750 	free(id);
751 	if (commit)
752 		got_object_commit_close(commit);
753 	if (tag)
754 		got_object_tag_close(tag);
755 	return err;
756 }
757 
758 const struct got_error *
759 got_ref_cmp_by_commit_timestamp_descending(void *arg, int *cmp,
760     struct got_reference *ref1, struct got_reference *ref2)
761 {
762 	const struct got_error *err = NULL;
763 	struct got_repository *repo = arg;
764 
765 	*cmp = 0;
766 
767 	if (ref1->committer_time == 0) {
768 		err = get_committer_time(ref1, repo);
769 		if (err)
770 			return err;
771 	}
772 	if (ref2->committer_time == 0) {
773 		err = get_committer_time(ref2, repo);
774 		if (err)
775 			return err;
776 	}
777 
778 	if (ref1->committer_time < ref2->committer_time)
779 		*cmp = 1;
780 	else if (ref2->committer_time < ref1->committer_time)
781 		*cmp = -1;
782 	else
783 		return got_ref_cmp_by_name(arg, cmp, ref1, ref2);
784 
785 	return err;
786 }
787 
788 const struct got_error *
789 got_reflist_insert(struct got_reflist_entry **newp,
790     struct got_reflist_head *refs, struct got_reference *ref,
791     got_ref_cmp_cb cmp_cb, void *cmp_arg)
792 {
793 	const struct got_error *err;
794 	struct got_reflist_entry *new, *re;
795 	int cmp;
796 
797 	*newp = NULL;
798 
799 	if (cmp_cb != got_ref_cmp_by_name && (ref->flags & GOT_REF_IS_PACKED)) {
800 		/*
801 		 * If we are not sorting elements by name then we must still
802 		 * detect collisions between a packed ref and an on-disk ref
803 		 * using the same name. On-disk refs take precedence and are
804 		 * already present on the list before packed refs get added.
805 		 */
806 		TAILQ_FOREACH(re, refs, entry) {
807 			err = got_ref_cmp_by_name(NULL, &cmp, re->ref, ref);
808 			if (err)
809 				return err;
810 			if (cmp == 0)
811 				return NULL;
812 		}
813 	}
814 
815 	new = malloc(sizeof(*new));
816 	if (new == NULL)
817 		return got_error_from_errno("malloc");
818 	new->ref = ref;
819 	*newp = new;
820 
821 	/*
822 	 * We must de-duplicate entries on insert because packed-refs may
823 	 * contain redundant entries. On-disk refs take precedence.
824 	 * This code assumes that on-disk revs are read before packed-refs.
825 	 * We're iterating the list anyway, so insert elements sorted by name.
826 	 *
827 	 * Many callers will provide paths in a somewhat sorted order.
828 	 * Iterating backwards from the tail of the list should be more
829 	 * efficient than traversing through the entire list each time
830 	 * an element is inserted.
831 	 */
832 	re = TAILQ_LAST(refs, got_reflist_head);
833 	while (re) {
834 		err = (*cmp_cb)(cmp_arg, &cmp, re->ref, new->ref);
835 		if (err)
836 			return err;
837 		if (cmp == 0) {
838 			/* duplicate */
839 			free(new);
840 			*newp = NULL;
841 			return NULL;
842 		} else if (cmp < 0) {
843 			TAILQ_INSERT_AFTER(refs, re, new, entry);
844 			return NULL;
845 		}
846 		re = TAILQ_PREV(re, got_reflist_head, entry);
847 	}
848 
849 	TAILQ_INSERT_HEAD(refs, new, entry);
850 	return NULL;
851 }
852 
853 const struct got_error *
854 got_reflist_sort(struct got_reflist_head *refs,
855     got_ref_cmp_cb cmp_cb, void *cmp_arg)
856 {
857 	const struct got_error *err = NULL;
858 	struct got_reflist_entry *re, *tmp, *new;
859 	struct got_reflist_head sorted;
860 
861 	TAILQ_INIT(&sorted);
862 
863 	TAILQ_FOREACH_SAFE(re, refs, entry, tmp) {
864 		struct got_reference *ref = re->ref;
865 		TAILQ_REMOVE(refs, re, entry);
866 		free(re);
867 		err = got_reflist_insert(&new, &sorted, ref, cmp_cb, cmp_arg);
868 		if (err || new == NULL /* duplicate */)
869 			got_ref_close(ref);
870 		if (err)
871 			return err;
872 	}
873 
874 	TAILQ_CONCAT(refs, &sorted, entry);
875 	return NULL;
876 }
877 
878 static const struct got_error *
879 gather_on_disk_refs(struct got_reflist_head *refs, const char *path_refs,
880     const char *subdir, struct got_repository *repo,
881     got_ref_cmp_cb cmp_cb, void *cmp_arg)
882 {
883 	const struct got_error *err = NULL;
884 	DIR *d = NULL;
885 	char *path_subdir;
886 
887 	while (subdir[0] == '/')
888 		subdir++;
889 
890 	if (asprintf(&path_subdir, "%s/%s", path_refs, subdir) == -1)
891 		return got_error_from_errno("asprintf");
892 
893 	d = opendir(path_subdir);
894 	if (d == NULL)
895 		goto done;
896 
897 	for (;;) {
898 		struct dirent *dent;
899 		struct got_reference *ref;
900 		char *child;
901 		int type;
902 
903 		dent = readdir(d);
904 		if (dent == NULL)
905 			break;
906 
907 		if (strcmp(dent->d_name, ".") == 0 ||
908 		    strcmp(dent->d_name, "..") == 0)
909 			continue;
910 
911 		err = got_path_dirent_type(&type, path_subdir, dent);
912 		if (err)
913 			break;
914 
915 		switch (type) {
916 		case DT_REG:
917 			err = open_ref(&ref, path_refs, subdir, dent->d_name,
918 			    0);
919 			if (err)
920 				goto done;
921 			if (ref) {
922 				struct got_reflist_entry *new;
923 				err = got_reflist_insert(&new, refs, ref,
924 				    cmp_cb, cmp_arg);
925 				if (err || new == NULL /* duplicate */)
926 					got_ref_close(ref);
927 				if (err)
928 					goto done;
929 			}
930 			break;
931 		case DT_DIR:
932 			if (asprintf(&child, "%s%s%s", subdir,
933 			    subdir[0] == '\0' ? "" : "/", dent->d_name) == -1) {
934 				err = got_error_from_errno("asprintf");
935 				break;
936 			}
937 			err = gather_on_disk_refs(refs, path_refs, child, repo,
938 			    cmp_cb, cmp_arg);
939 			free(child);
940 			break;
941 		default:
942 			break;
943 		}
944 	}
945 done:
946 	if (d)
947 		closedir(d);
948 	free(path_subdir);
949 	return err;
950 }
951 
952 const struct got_error *
953 got_ref_list(struct got_reflist_head *refs, struct got_repository *repo,
954     const char *ref_namespace, got_ref_cmp_cb cmp_cb, void *cmp_arg)
955 {
956 	const struct got_error *err;
957 	char *packed_refs_path = NULL, *path_refs = NULL;
958 	char *abs_namespace = NULL, *buf = NULL;
959 	const char *ondisk_ref_namespace = NULL;
960 	char *line = NULL;
961 	FILE *f = NULL;
962 	struct got_reference *ref;
963 	struct got_reflist_entry *new;
964 
965 	if (ref_namespace == NULL || ref_namespace[0] == '\0') {
966 		path_refs = get_refs_dir_path(repo, GOT_REF_HEAD);
967 		if (path_refs == NULL) {
968 			err = got_error_from_errno("get_refs_dir_path");
969 			goto done;
970 		}
971 		err = open_ref(&ref, path_refs, "", GOT_REF_HEAD, 0);
972 		if (err)
973 			goto done;
974 		err = got_reflist_insert(&new, refs, ref, cmp_cb, cmp_arg);
975 		if (err || new == NULL /* duplicate */)
976 			got_ref_close(ref);
977 		if (err && err->code != GOT_ERR_NOT_REF)
978 			goto done;
979 	} else {
980 		/* Try listing a single reference. */
981 		const char *refname = ref_namespace;
982 		path_refs = get_refs_dir_path(repo, refname);
983 		if (path_refs == NULL) {
984 			err = got_error_from_errno("get_refs_dir_path");
985 			goto done;
986 		}
987 		err = open_ref(&ref, path_refs, "", refname, 0);
988 		if (err) {
989 			if (err->code != GOT_ERR_NOT_REF)
990 				goto done;
991 			/* Try to look up references in a given namespace. */
992 		} else {
993 			err = got_reflist_insert(&new, refs, ref,
994 			    cmp_cb, cmp_arg);
995 			if (err || new == NULL /* duplicate */)
996 				got_ref_close(ref);
997 			return err;
998 		}
999 	}
1000 
1001 	if (ref_namespace) {
1002 		size_t len;
1003 		/* Canonicalize the path to eliminate double-slashes if any. */
1004 		if (asprintf(&abs_namespace, "/%s", ref_namespace) == -1) {
1005 			err = got_error_from_errno("asprintf");
1006 			goto done;
1007 		}
1008 		len = strlen(abs_namespace) + 1;
1009 		buf = malloc(len);
1010 		if (buf == NULL) {
1011 			err = got_error_from_errno("malloc");
1012 			goto done;
1013 		}
1014 		err = got_canonpath(abs_namespace, buf, len);
1015 		if (err)
1016 			goto done;
1017 		ondisk_ref_namespace = buf;
1018 		while (ondisk_ref_namespace[0] == '/')
1019 			ondisk_ref_namespace++;
1020 		if (strncmp(ondisk_ref_namespace, "refs/", 5) == 0)
1021 			ondisk_ref_namespace += 5;
1022 		else if (strcmp(ondisk_ref_namespace, "refs") == 0)
1023 			ondisk_ref_namespace = "";
1024 	}
1025 
1026 	/* Gather on-disk refs before parsing packed-refs. */
1027 	free(path_refs);
1028 	path_refs = get_refs_dir_path(repo, "");
1029 	if (path_refs == NULL) {
1030 		err = got_error_from_errno("get_refs_dir_path");
1031 		goto done;
1032 	}
1033 	err = gather_on_disk_refs(refs, path_refs,
1034 	    ondisk_ref_namespace ? ondisk_ref_namespace : "", repo,
1035 	    cmp_cb, cmp_arg);
1036 	if (err)
1037 		goto done;
1038 
1039 	/*
1040 	 * The packed-refs file may contain redundant entries, in which
1041 	 * case on-disk refs take precedence.
1042 	 */
1043 	packed_refs_path = got_repo_get_path_packed_refs(repo);
1044 	if (packed_refs_path == NULL) {
1045 		err = got_error_from_errno("got_repo_get_path_packed_refs");
1046 		goto done;
1047 	}
1048 
1049 	f = fopen(packed_refs_path, "re");
1050 	if (f) {
1051 		size_t linesize = 0;
1052 		ssize_t linelen;
1053 		struct stat sb;
1054 
1055 		if (fstat(fileno(f), &sb) == -1) {
1056 			err = got_error_from_errno2("fstat", packed_refs_path);
1057 			goto done;
1058 		}
1059 		for (;;) {
1060 			linelen = getline(&line, &linesize, f);
1061 			if (linelen == -1) {
1062 				if (feof(f))
1063 					break;
1064 				err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
1065 				goto done;
1066 			}
1067 			if (linelen > 0 && line[linelen - 1] == '\n')
1068 				line[linelen - 1] = '\0';
1069 			err = parse_packed_ref_line(&ref, NULL, line,
1070 			    sb.st_mtime);
1071 			if (err)
1072 				goto done;
1073 			if (ref) {
1074 				if (ref_namespace) {
1075 					const char *name;
1076 					name = got_ref_get_name(ref);
1077 					if (!got_path_is_child(name,
1078 					    ref_namespace,
1079 					    strlen(ref_namespace))) {
1080 						got_ref_close(ref);
1081 						continue;
1082 					}
1083 				}
1084 				err = got_reflist_insert(&new, refs, ref,
1085 				    cmp_cb, cmp_arg);
1086 				if (err || new == NULL /* duplicate */)
1087 					got_ref_close(ref);
1088 				if (err)
1089 					goto done;
1090 			}
1091 		}
1092 	}
1093 done:
1094 	free(packed_refs_path);
1095 	free(abs_namespace);
1096 	free(buf);
1097 	free(line);
1098 	free(path_refs);
1099 	if (f && fclose(f) == EOF && err == NULL)
1100 		err = got_error_from_errno("fclose");
1101 	return err;
1102 }
1103 
1104 void
1105 got_ref_list_free(struct got_reflist_head *refs)
1106 {
1107 	struct got_reflist_entry *re;
1108 
1109 	while ((re = TAILQ_FIRST(refs))) {
1110 		TAILQ_REMOVE(refs, re, entry);
1111 		got_ref_close(re->ref);
1112 		free(re);
1113 	}
1114 }
1115 
1116 int
1117 got_ref_is_symbolic(struct got_reference *ref)
1118 {
1119 	return (ref->flags & GOT_REF_IS_SYMBOLIC);
1120 }
1121 
1122 const struct got_error *
1123 got_ref_change_ref(struct got_reference *ref, struct got_object_id *id)
1124 {
1125 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
1126 		return got_error(GOT_ERR_BAD_REF_TYPE);
1127 
1128 	memcpy(&ref->ref.ref.id, id, sizeof(ref->ref.ref.id));
1129 	return NULL;
1130 }
1131 
1132 const struct got_error *
1133 got_ref_change_symref(struct got_reference *ref, const char *refname)
1134 {
1135 	char *new_name;
1136 
1137 	if ((ref->flags & GOT_REF_IS_SYMBOLIC) == 0)
1138 		return got_error(GOT_ERR_BAD_REF_TYPE);
1139 
1140 	new_name = strdup(refname);
1141 	if (new_name == NULL)
1142 		return got_error_from_errno("strdup");
1143 
1144 	free(ref->ref.symref.ref);
1145 	ref->ref.symref.ref = new_name;
1146 	return NULL;
1147 }
1148 
1149 const struct got_error *
1150 got_ref_change_symref_to_ref(struct got_reference *symref,
1151     struct got_object_id *id)
1152 {
1153 	if ((symref->flags & GOT_REF_IS_SYMBOLIC) == 0)
1154 		return got_error(GOT_ERR_BAD_REF_TYPE);
1155 
1156 	symref->ref.ref.name = symref->ref.symref.name;
1157 	memcpy(&symref->ref.ref.id, id, sizeof(symref->ref.ref.id));
1158 	symref->flags &= ~GOT_REF_IS_SYMBOLIC;
1159 	return NULL;
1160 }
1161 
1162 const struct got_error *
1163 got_ref_write(struct got_reference *ref, struct got_repository *repo)
1164 {
1165 	const struct got_error *err = NULL, *unlock_err = NULL;
1166 	const char *name = got_ref_get_name(ref);
1167 	char *path_refs = NULL, *path = NULL, *tmppath = NULL;
1168 	struct got_lockfile *lf = NULL;
1169 	FILE *f = NULL;
1170 	size_t n;
1171 	struct stat sb;
1172 
1173 	path_refs = get_refs_dir_path(repo, name);
1174 	if (path_refs == NULL) {
1175 		err = got_error_from_errno2("get_refs_dir_path", name);
1176 		goto done;
1177 	}
1178 
1179 	if (asprintf(&path, "%s/%s", path_refs, name) == -1) {
1180 		err = got_error_from_errno("asprintf");
1181 		goto done;
1182 	}
1183 
1184 	err = got_opentemp_named(&tmppath, &f, path, "");
1185 	if (err) {
1186 		char *parent;
1187 		if (!(err->code == GOT_ERR_ERRNO && errno == ENOENT))
1188 			goto done;
1189 		err = got_path_dirname(&parent, path);
1190 		if (err)
1191 			goto done;
1192 		err = got_path_mkdir(parent);
1193 		free(parent);
1194 		if (err)
1195 			goto done;
1196 		err = got_opentemp_named(&tmppath, &f, path, "");
1197 		if (err)
1198 			goto done;
1199 	}
1200 
1201 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
1202 		n = fprintf(f, "ref: %s\n", ref->ref.symref.ref);
1203 		if (n != strlen(ref->ref.symref.ref) + 6) {
1204 			err = got_ferror(f, GOT_ERR_IO);
1205 			goto done;
1206 		}
1207 	} else {
1208 		char *hex;
1209 		size_t len;
1210 
1211 		err = got_object_id_str(&hex, &ref->ref.ref.id);
1212 		if (err)
1213 			goto done;
1214 		len = strlen(hex);
1215 		n = fprintf(f, "%s\n", hex);
1216 		free(hex);
1217 		if (n != len + 1) {
1218 			err = got_ferror(f, GOT_ERR_IO);
1219 			goto done;
1220 		}
1221 	}
1222 
1223 	if (ref->lf == NULL) {
1224 		err = got_lockfile_lock(&lf, path, -1);
1225 		if (err)
1226 			goto done;
1227 	}
1228 
1229 	/* XXX: check if old content matches our expectations? */
1230 
1231 	if (stat(path, &sb) != 0) {
1232 		if (errno != ENOENT) {
1233 			err = got_error_from_errno2("stat", path);
1234 			goto done;
1235 		}
1236 		sb.st_mode = GOT_DEFAULT_FILE_MODE;
1237 	}
1238 
1239 	if (fchmod(fileno(f), sb.st_mode) != 0) {
1240 		err = got_error_from_errno2("fchmod", tmppath);
1241 		goto done;
1242 	}
1243 
1244 	if (rename(tmppath, path) != 0) {
1245 		err = got_error_from_errno3("rename", tmppath, path);
1246 		goto done;
1247 	}
1248 	free(tmppath);
1249 	tmppath = NULL;
1250 
1251 	if (stat(path, &sb) == -1) {
1252 		err = got_error_from_errno2("stat", path);
1253 		goto done;
1254 	}
1255 	ref->mtime = sb.st_mtime;
1256 done:
1257 	if (ref->lf == NULL && lf)
1258 		unlock_err = got_lockfile_unlock(lf, -1);
1259 	if (f) {
1260 		if (fclose(f) == EOF && err == NULL)
1261 			err = got_error_from_errno("fclose");
1262 	}
1263 	free(path_refs);
1264 	free(path);
1265 	if (tmppath) {
1266 		if (unlink(tmppath) == -1 && err == NULL)
1267 			err = got_error_from_errno2("unlink", tmppath);
1268 		free(tmppath);
1269 	}
1270 	return err ? err : unlock_err;
1271 }
1272 
1273 static const struct got_error *
1274 delete_packed_ref(struct got_reference *delref, struct got_repository *repo)
1275 {
1276 	const struct got_error *err = NULL, *unlock_err = NULL;
1277 	struct got_lockfile *lf = NULL;
1278 	FILE *f = NULL, *tmpf = NULL;
1279 	char *line = NULL, *packed_refs_path, *tmppath = NULL;
1280 	size_t linesize = 0;
1281 	struct got_reflist_head refs;
1282 	int found_delref = 0;
1283 
1284 	/* The packed-refs file does not cotain symbolic references. */
1285 	if (delref->flags & GOT_REF_IS_SYMBOLIC)
1286 		return got_error(GOT_ERR_BAD_REF_DATA);
1287 
1288 	TAILQ_INIT(&refs);
1289 
1290 	packed_refs_path = got_repo_get_path_packed_refs(repo);
1291 	if (packed_refs_path == NULL)
1292 		return got_error_from_errno("got_repo_get_path_packed_refs");
1293 
1294 	err = got_opentemp_named(&tmppath, &tmpf, packed_refs_path, "");
1295 	if (err)
1296 		goto done;
1297 
1298 	if (delref->lf == NULL) {
1299 		err = got_lockfile_lock(&lf, packed_refs_path, -1);
1300 		if (err)
1301 			goto done;
1302 	}
1303 
1304 	f = fopen(packed_refs_path, "re");
1305 	if (f == NULL) {
1306 		err = got_error_from_errno2("fopen", packed_refs_path);
1307 		goto done;
1308 	}
1309 	for (;;) {
1310 		ssize_t linelen;
1311 		struct got_reference *ref;
1312 		struct got_reflist_entry *new;
1313 
1314 		linelen = getline(&line, &linesize, f);
1315 		if (linelen == -1) {
1316 			if (feof(f))
1317 				break;
1318 			err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
1319 			goto done;
1320 		}
1321 		if (linelen > 0 && line[linelen - 1] == '\n')
1322 			line[linelen - 1] = '\0';
1323 		err = parse_packed_ref_line(&ref, NULL, line, 0);
1324 		if (err)
1325 			goto done;
1326 		if (ref == NULL)
1327 			continue;
1328 
1329 		if (strcmp(ref->ref.ref.name, delref->ref.ref.name) == 0 &&
1330 		    got_object_id_cmp(&ref->ref.ref.id,
1331 		    &delref->ref.ref.id) == 0) {
1332 			found_delref = 1;
1333 			got_ref_close(ref);
1334 			continue;
1335 		}
1336 
1337 		err = got_reflist_insert(&new, &refs, ref,
1338 		    got_ref_cmp_by_name, NULL);
1339 		if (err || new == NULL /* duplicate */)
1340 			got_ref_close(ref);
1341 		if (err)
1342 			goto done;
1343 	}
1344 
1345 	if (found_delref) {
1346 		struct got_reflist_entry *re;
1347 		size_t n;
1348 		struct stat sb;
1349 
1350 		n = fprintf(tmpf, "%s\n", GOT_PACKED_REFS_HEADER);
1351 		if (n != sizeof(GOT_PACKED_REFS_HEADER)) {
1352 			err = got_ferror(f, GOT_ERR_IO);
1353 			goto done;
1354 		}
1355 
1356 		TAILQ_FOREACH(re, &refs, entry) {
1357 			char *hex;
1358 			size_t len;
1359 
1360 			err = got_object_id_str(&hex, &re->ref->ref.ref.id);
1361 			if (err)
1362 				goto done;
1363 			len = strlen(hex);
1364 			n = fprintf(tmpf, "%s ", hex);
1365 			free(hex);
1366 			if (n != len + 1) {
1367 				err = got_ferror(f, GOT_ERR_IO);
1368 				goto done;
1369 			}
1370 
1371 			n = fprintf(tmpf, "%s\n", re->ref->ref.ref.name);
1372 			if (n != strlen(re->ref->ref.ref.name) + 1) {
1373 				err = got_ferror(f, GOT_ERR_IO);
1374 				goto done;
1375 			}
1376 		}
1377 
1378 		if (fflush(tmpf) != 0) {
1379 			err = got_error_from_errno("fflush");
1380 			goto done;
1381 		}
1382 
1383 		if (fstat(fileno(f), &sb) != 0) {
1384 			if (errno != ENOENT) {
1385 				err = got_error_from_errno2("fstat",
1386 				    packed_refs_path);
1387 				goto done;
1388 			}
1389 			sb.st_mode = GOT_DEFAULT_FILE_MODE;
1390 		}
1391 
1392 		if (fchmod(fileno(tmpf), sb.st_mode) != 0) {
1393 			err = got_error_from_errno2("fchmod", tmppath);
1394 			goto done;
1395 		}
1396 
1397 		if (rename(tmppath, packed_refs_path) != 0) {
1398 			err = got_error_from_errno3("rename", tmppath,
1399 			    packed_refs_path);
1400 			goto done;
1401 		}
1402 		free(tmppath);
1403 		tmppath = NULL;
1404 	}
1405 done:
1406 	if (delref->lf == NULL && lf)
1407 		unlock_err = got_lockfile_unlock(lf, -1);
1408 	if (f) {
1409 		if (fclose(f) == EOF && err == NULL)
1410 			err = got_error_from_errno("fclose");
1411 	}
1412 	if (tmppath && unlink(tmppath) == -1 && err == NULL)
1413 		err = got_error_from_errno2("unlink", tmppath);
1414 	if (tmpf && fclose(tmpf) == EOF && err == NULL)
1415 		err = got_error_from_errno("fclose");
1416 	free(tmppath);
1417 	free(packed_refs_path);
1418 	free(line);
1419 	got_ref_list_free(&refs);
1420 	return err ? err : unlock_err;
1421 }
1422 
1423 static const struct got_error *
1424 delete_loose_ref(struct got_reference *ref, struct got_repository *repo)
1425 {
1426 	const struct got_error *err = NULL, *unlock_err = NULL;
1427 	const char *name = got_ref_get_name(ref);
1428 	char *path_refs = NULL, *path = NULL;
1429 	struct got_lockfile *lf = NULL;
1430 
1431 	path_refs = get_refs_dir_path(repo, name);
1432 	if (path_refs == NULL) {
1433 		err = got_error_from_errno2("get_refs_dir_path", name);
1434 		goto done;
1435 	}
1436 
1437 	if (asprintf(&path, "%s/%s", path_refs, name) == -1) {
1438 		err = got_error_from_errno("asprintf");
1439 		goto done;
1440 	}
1441 
1442 	if (ref->lf == NULL) {
1443 		err = got_lockfile_lock(&lf, path, -1);
1444 		if (err)
1445 			goto done;
1446 	}
1447 
1448 	/* XXX: check if old content matches our expectations? */
1449 
1450 	if (unlink(path) == -1)
1451 		err = got_error_from_errno2("unlink", path);
1452 done:
1453 	if (ref->lf == NULL && lf)
1454 		unlock_err = got_lockfile_unlock(lf, -1);
1455 
1456 	free(path_refs);
1457 	free(path);
1458 	return err ? err : unlock_err;
1459 }
1460 
1461 const struct got_error *
1462 got_ref_delete(struct got_reference *ref, struct got_repository *repo)
1463 {
1464 	const struct got_error *err = NULL;
1465 	struct got_reference *ref2;
1466 
1467 	if (ref->flags & GOT_REF_IS_PACKED) {
1468 		err = delete_packed_ref(ref, repo);
1469 		if (err)
1470 			return err;
1471 
1472 		err = got_ref_open(&ref2, repo, got_ref_get_name(ref), 0);
1473 		if (err) {
1474 			if (err->code == GOT_ERR_NOT_REF)
1475 				return NULL;
1476 			return err;
1477 		}
1478 
1479 		err = delete_loose_ref(ref2, repo);
1480 		got_ref_close(ref2);
1481 		return err;
1482 	} else {
1483 		err = delete_loose_ref(ref, repo);
1484 		if (err)
1485 			return err;
1486 
1487 		err = got_ref_open(&ref2, repo, got_ref_get_name(ref), 0);
1488 		if (err) {
1489 			if (err->code == GOT_ERR_NOT_REF)
1490 				return NULL;
1491 			return err;
1492 		}
1493 
1494 		err = delete_packed_ref(ref2, repo);
1495 		got_ref_close(ref2);
1496 		return err;
1497 	}
1498 }
1499 
1500 const struct got_error *
1501 got_ref_unlock(struct got_reference *ref)
1502 {
1503 	const struct got_error *err;
1504 	err = got_lockfile_unlock(ref->lf, -1);
1505 	ref->lf = NULL;
1506 	return err;
1507 }
1508 
1509 struct got_reflist_object_id_map {
1510 	struct got_object_idset *idset;
1511 };
1512 
1513 struct got_reflist_object_id_map_entry {
1514 	struct got_reflist_head refs;
1515 };
1516 
1517 static const struct got_error *
1518 add_object_id_map_entry(struct got_object_idset *idset,
1519     struct got_object_id *id, struct got_reflist_entry *re)
1520 {
1521 	const struct got_error *err = NULL;
1522 	struct got_reflist_object_id_map_entry *ent;
1523 	struct got_reflist_entry *new;
1524 
1525 	ent = got_object_idset_get(idset, id);
1526 	if (ent == NULL) {
1527 		ent = malloc(sizeof(*ent));
1528 		if (ent == NULL)
1529 			return got_error_from_errno("malloc");
1530 
1531 		TAILQ_INIT(&ent->refs);
1532 		err = got_object_idset_add(idset, id, ent);
1533 		if (err) {
1534 			free(ent);
1535 			return err;
1536 		}
1537 	}
1538 
1539 	err = got_reflist_entry_dup(&new, re);
1540 	if (err)
1541 		return err;
1542 
1543 	TAILQ_INSERT_TAIL(&ent->refs, new, entry);
1544 	return NULL;
1545 }
1546 
1547 const struct got_error *
1548 got_reflist_object_id_map_create(struct got_reflist_object_id_map **map,
1549     struct got_reflist_head *refs, struct got_repository *repo)
1550 {
1551 	const struct got_error *err = NULL;
1552 	struct got_object_idset *idset;
1553 	struct got_object_id *id = NULL;
1554 	struct got_reflist_entry *re;
1555 
1556 	idset = got_object_idset_alloc();
1557 	if (idset == NULL)
1558 		return got_error_from_errno("got_object_idset_alloc");
1559 
1560 	*map = malloc(sizeof(**map));
1561 	if (*map == NULL) {
1562 		got_object_idset_free(idset);
1563 		return got_error_from_errno("malloc");
1564 	}
1565 	(*map)->idset = idset;
1566 
1567 	TAILQ_FOREACH(re, refs, entry) {
1568 		struct got_tag_object *tag = NULL;
1569 
1570 		err = got_ref_resolve(&id, repo, re->ref);
1571 		if (err)
1572 			goto done;
1573 
1574 		err = add_object_id_map_entry(idset, id, re);
1575 		if (err)
1576 			goto done;
1577 
1578 		if (strstr(got_ref_get_name(re->ref), "/tags/") == NULL) {
1579 			free(id);
1580 			id = NULL;
1581 			continue;
1582 		}
1583 
1584 		err = got_object_open_as_tag(&tag, repo, id);
1585 		if (err) {
1586 			if (err->code != GOT_ERR_OBJ_TYPE)
1587 				goto done;
1588 			/* Ref points at something other than a tag. */
1589 			err = NULL;
1590 			tag = NULL;
1591 			free(id);
1592 			id = NULL;
1593 			continue;
1594 		}
1595 
1596 		err = add_object_id_map_entry(idset,
1597 		    got_object_tag_get_object_id(tag), re);
1598 		got_object_tag_close(tag);
1599 		if (err)
1600 			goto done;
1601 
1602 		free(id);
1603 		id = NULL;
1604 	}
1605 done:
1606 	free(id);
1607 	if (err) {
1608 		got_reflist_object_id_map_free(*map);
1609 		*map = NULL;
1610 	}
1611 	return err;
1612 }
1613 
1614 struct got_reflist_head *
1615 got_reflist_object_id_map_lookup(struct got_reflist_object_id_map *map,
1616     struct got_object_id *id)
1617 {
1618 	struct got_reflist_object_id_map_entry *ent;
1619 	ent = got_object_idset_get(map->idset, id);
1620 	if (ent)
1621 		return &ent->refs;
1622 	return NULL;
1623 }
1624 
1625 static const struct got_error *
1626 free_id_map_entry(struct got_object_id *id, void *data, void *arg)
1627 {
1628 	struct got_reflist_object_id_map_entry *ent = data;
1629 
1630 	got_ref_list_free(&ent->refs);
1631 	free(ent);
1632 	return NULL;
1633 }
1634 
1635 void
1636 got_reflist_object_id_map_free(struct got_reflist_object_id_map *map)
1637 {
1638 	got_object_idset_for_each(map->idset, free_id_map_entry, NULL);
1639 	got_object_idset_free(map->idset);
1640 	free(map);
1641 }