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 <stdio.h>
25 #include <stdlib.h>
26 #include <string.h>
27 #include <unistd.h>
28 #include <zlib.h>
29 #include <time.h>
30 #include <libgen.h>
31 
32 #include "got_compat.h"
33 
34 #include "got_error.h"
35 #include "got_object.h"
36 #include "got_repository.h"
37 #include "got_reference.h"
38 #include "got_opentemp.h"
39 #include "got_path.h"
40 
41 #include "got_lib_hash.h"
42 #include "got_lib_delta.h"
43 #include "got_lib_inflate.h"
44 #include "got_lib_object.h"
45 #include "got_lib_object_idset.h"
46 #include "got_lib_lockfile.h"
47 
48 #ifndef nitems
49 #define nitems(_a) (sizeof(_a) / sizeof((_a)[0]))
50 #endif
51 
52 #define GOT_REF_HEADS	"heads"
53 #define GOT_REF_TAGS	"tags"
54 #define GOT_REF_REMOTES	"remotes"
55 
56 /*
57  * We do not resolve tags yet, and don't yet care about sorting refs either,
58  * so packed-refs files we write contain a minimal header which disables all
59  * packed-refs "traits" supported by Git.
60  */
61 #define GOT_PACKED_REFS_HEADER	"# pack-refs with:"
62 
63 /* A symbolic reference. */
64 struct got_symref {
65 	char *name;
66 	char *ref;
67 };
68 
69 #define GOT_REF_RECURSE_MAX	20
70 
71 /* A non-symbolic reference (there is no better designation). */
72 struct got_ref {
73 	char *name;
74 	struct got_object_id id;
75 };
76 
77 /* A reference which points to an arbitrary object. */
78 struct got_reference {
79 	unsigned int flags;
80 #define GOT_REF_IS_SYMBOLIC	0x01
81 #define GOT_REF_IS_PACKED	0x02
82 
83 	union {
84 		struct got_ref ref;
85 		struct got_symref symref;
86 	} ref;
87 
88 	struct got_lockfile *lf;
89 	time_t mtime;
90 
91 	/* Cached timestamp for got_ref_cmp_by_commit_timestamp_descending() */
92 	time_t committer_time;
93 };
94 
95 static const struct got_error *
96 alloc_ref(struct got_reference **ref, const char *name,
97     struct got_object_id *id, int flags, time_t mtime)
98 {
99 	const struct got_error *err = NULL;
100 
101 	*ref = calloc(1, sizeof(**ref));
102 	if (*ref == NULL)
103 		return got_error_from_errno("calloc");
104 
105 	memcpy(&(*ref)->ref.ref.id, id, sizeof((*ref)->ref.ref.id));
106 	(*ref)->flags = flags;
107 	(*ref)->ref.ref.name = strdup(name);
108 	(*ref)->mtime = mtime;
109 	if ((*ref)->ref.ref.name == NULL) {
110 		err = got_error_from_errno("strdup");
111 		got_ref_close(*ref);
112 		*ref = NULL;
113 	}
114 	return err;
115 }
116 
117 static const struct got_error *
118 alloc_symref(struct got_reference **ref, const char *name,
119     const char *target_ref, int flags)
120 {
121 	const struct got_error *err = NULL;
122 
123 	*ref = calloc(1, sizeof(**ref));
124 	if (*ref == NULL)
125 		return got_error_from_errno("calloc");
126 
127 	(*ref)->flags = GOT_REF_IS_SYMBOLIC | flags;
128 	(*ref)->ref.symref.name = strdup(name);
129 	if ((*ref)->ref.symref.name == NULL) {
130 		err = got_error_from_errno("strdup");
131 		got_ref_close(*ref);
132 		*ref = NULL;
133 		return err;
134 	}
135 	(*ref)->ref.symref.ref = strdup(target_ref);
136 	if ((*ref)->ref.symref.ref == NULL) {
137 		err = got_error_from_errno("strdup");
138 		got_ref_close(*ref);
139 		*ref = NULL;
140 	}
141 	return err;
142 }
143 
144 static const struct got_error *
145 parse_symref(struct got_reference **ref, const char *name, const char *line)
146 {
147 	if (line[0] == '\0')
148 		return got_error(GOT_ERR_BAD_REF_DATA);
149 
150 	return alloc_symref(ref, name, line, 0);
151 }
152 
153 static const struct got_error *
154 parse_ref_line(struct got_reference **ref, const char *name, const char *line,
155     time_t mtime)
156 {
157 	enum got_hash_algorithm algo = GOT_HASH_SHA1;
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_object_id(&id, line, algo))
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 	enum got_hash_algorithm algo = GOT_HASH_SHA1;
296 	struct got_object_id id;
297 	const char *name;
298 
299 	*ref = NULL;
300 
301 	if (line[0] == '#' || line[0] == '^')
302 		return NULL;
303 
304 	if (!got_parse_object_id(&id, line, algo))
305 		return got_error(GOT_ERR_BAD_REF_DATA);
306 
307 	if (abs_refname) {
308 		if (strcmp(line + SHA1_DIGEST_STRING_LENGTH, abs_refname) != 0)
309 			return NULL;
310 		name = abs_refname;
311 	} else
312 		name = line + SHA1_DIGEST_STRING_LENGTH;
313 
314 	return alloc_ref(ref, name, &id, GOT_REF_IS_PACKED, mtime);
315 }
316 
317 static const struct got_error *
318 open_packed_ref(struct got_reference **ref, FILE *f, const char **subdirs,
319     int nsubdirs, const char *refname, time_t mtime)
320 {
321 	const struct got_error *err = NULL;
322 	char *abs_refname;
323 	char *line = NULL;
324 	size_t linesize = 0;
325 	ssize_t linelen;
326 	int i, ref_is_absolute = (strncmp(refname, "refs/", 5) == 0);
327 
328 	*ref = NULL;
329 
330 	if (ref_is_absolute)
331 		abs_refname = (char *)refname;
332 	do {
333 		linelen = getline(&line, &linesize, f);
334 		if (linelen == -1) {
335 			if (feof(f))
336 				break;
337 			err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
338 			break;
339 		}
340 		if (linelen > 0 && line[linelen - 1] == '\n')
341 			line[linelen - 1] = '\0';
342 		for (i = 0; i < nsubdirs; i++) {
343 			if (!ref_is_absolute &&
344 			    asprintf(&abs_refname, "refs/%s/%s", subdirs[i],
345 			    refname) == -1)
346 				return got_error_from_errno("asprintf");
347 			err = parse_packed_ref_line(ref, abs_refname, line,
348 			    mtime);
349 			if (!ref_is_absolute)
350 				free(abs_refname);
351 			if (err || *ref != NULL)
352 				break;
353 		}
354 		if (err)
355 			break;
356 	} while (*ref == NULL);
357 	free(line);
358 
359 	return err;
360 }
361 
362 static const struct got_error *
363 open_ref(struct got_reference **ref, const char *path_refs, const char *subdir,
364     const char *name, int lock)
365 {
366 	const struct got_error *err = NULL;
367 	char *path = NULL;
368 	char *absname = NULL;
369 	int ref_is_absolute = (strncmp(name, "refs/", 5) == 0);
370 	int ref_is_well_known = (subdir[0] == '\0' && is_well_known_ref(name));
371 
372 	*ref = NULL;
373 
374 	if (!got_ref_name_is_valid(name))
375 		return got_error_path(name, GOT_ERR_BAD_REF_NAME);
376 
377 	if (ref_is_absolute || ref_is_well_known) {
378 		if (asprintf(&path, "%s/%s", path_refs, name) == -1)
379 			return got_error_from_errno("asprintf");
380 		absname = (char *)name;
381 	} else {
382 		if (asprintf(&path, "%s/%s%s%s", path_refs, subdir,
383 		    subdir[0] ? "/" : "", name) == -1)
384 			return got_error_from_errno("asprintf");
385 
386 		if (asprintf(&absname, "refs/%s%s%s",
387 		    subdir, subdir[0] ? "/" : "", name) == -1) {
388 			err = got_error_from_errno("asprintf");
389 			goto done;
390 		}
391 	}
392 
393 	err = parse_ref_file(ref, name, absname, path, lock);
394 done:
395 	if (!ref_is_absolute && !ref_is_well_known)
396 		free(absname);
397 	free(path);
398 	return err;
399 }
400 
401 const struct got_error *
402 got_ref_open(struct got_reference **ref, struct got_repository *repo,
403     const char *refname, int lock)
404 {
405 	const struct got_error *err = NULL;
406 	char *packed_refs_path = NULL, *path_refs = NULL;
407 	const char *subdirs[] = {
408 	    GOT_REF_HEADS, GOT_REF_TAGS, GOT_REF_REMOTES
409 	};
410 	size_t i;
411 	int well_known = is_well_known_ref(refname);
412 	struct got_lockfile *lf = NULL;
413 
414 	*ref = NULL;
415 
416 	path_refs = get_refs_dir_path(repo, refname);
417 	if (path_refs == NULL) {
418 		err = got_error_from_errno2("get_refs_dir_path", refname);
419 		goto done;
420 	}
421 
422 	if (well_known) {
423 		err = open_ref(ref, path_refs, "", refname, lock);
424 	} else {
425 		FILE *f;
426 
427 		/* Search on-disk refs before packed refs! */
428 		for (i = 0; i < nitems(subdirs); i++) {
429 			err = open_ref(ref, path_refs, subdirs[i], refname,
430 			    lock);
431 			if ((err && err->code != GOT_ERR_NOT_REF) || *ref)
432 				goto done;
433 		}
434 
435 		packed_refs_path = got_repo_get_path_packed_refs(repo);
436 		if (packed_refs_path == NULL) {
437 			err = got_error_from_errno(
438 			    "got_repo_get_path_packed_refs");
439 			goto done;
440 		}
441 
442 		if (lock) {
443 			err = got_lockfile_lock(&lf, packed_refs_path, -1);
444 			if (err)
445 				goto done;
446 		}
447 		f = fopen(packed_refs_path, "rbe");
448 		if (f != NULL) {
449 			struct stat sb;
450 			if (fstat(fileno(f), &sb) == -1) {
451 				err = got_error_from_errno2("fstat",
452 				    packed_refs_path);
453 				goto done;
454 			}
455 			err = open_packed_ref(ref, f, subdirs, nitems(subdirs),
456 			    refname, sb.st_mtime);
457 			if (!err) {
458 				if (fclose(f) == EOF) {
459 					err = got_error_from_errno("fclose");
460 					got_ref_close(*ref);
461 					*ref = NULL;
462 				} else if (*ref)
463 					(*ref)->lf = lf;
464 			}
465 		}
466 	}
467 done:
468 	if (!err && *ref == NULL)
469 		err = got_error_not_ref(refname);
470 	if (err && lf)
471 		got_lockfile_unlock(lf, -1);
472 	free(packed_refs_path);
473 	free(path_refs);
474 	return err;
475 }
476 
477 void
478 got_ref_close(struct got_reference *ref)
479 {
480 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
481 		free(ref->ref.symref.name);
482 		free(ref->ref.symref.ref);
483 	} else
484 		free(ref->ref.ref.name);
485 	free(ref);
486 }
487 
488 struct got_reference *
489 got_ref_dup(struct got_reference *ref)
490 {
491 	struct got_reference *ret;
492 
493 	ret = calloc(1, sizeof(*ret));
494 	if (ret == NULL)
495 		return NULL;
496 
497 	ret->flags = ref->flags;
498 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
499 		ret->ref.symref.name = strdup(ref->ref.symref.name);
500 		if (ret->ref.symref.name == NULL) {
501 			free(ret);
502 			return NULL;
503 		}
504 		ret->ref.symref.ref = strdup(ref->ref.symref.ref);
505 		if (ret->ref.symref.ref == NULL) {
506 			free(ret->ref.symref.name);
507 			free(ret);
508 			return NULL;
509 		}
510 	} else {
511 		ret->ref.ref.name = strdup(ref->ref.ref.name);
512 		if (ret->ref.ref.name == NULL) {
513 			free(ret);
514 			return NULL;
515 		}
516 		memcpy(&ret->ref.ref.id, &ref->ref.ref.id,
517 		    sizeof(ret->ref.ref.id));
518 	}
519 
520 	return ret;
521 }
522 
523 const struct got_error *
524 got_reflist_entry_dup(struct got_reflist_entry **newp,
525     struct got_reflist_entry *re)
526 {
527 	const struct got_error *err = NULL;
528 	struct got_reflist_entry *new;
529 
530 	*newp = NULL;
531 
532 	new = malloc(sizeof(*new));
533 	if (new == NULL)
534 		return got_error_from_errno("malloc");
535 
536 	new->ref = got_ref_dup(re->ref);
537 	if (new->ref == NULL) {
538 		err = got_error_from_errno("got_ref_dup");
539 		free(new);
540 		return err;
541 	}
542 
543 	*newp = new;
544 	return NULL;
545 }
546 
547 const struct got_error *
548 got_ref_resolve_symbolic(struct got_reference **resolved,
549     struct got_repository *repo, struct got_reference *ref)
550 {
551 	struct got_reference *nextref;
552 	const struct got_error *err;
553 
554 	err = got_ref_open(&nextref, repo, ref->ref.symref.ref, 0);
555 	if (err)
556 		return err;
557 
558 	if (nextref->flags & GOT_REF_IS_SYMBOLIC)
559 		err = got_ref_resolve_symbolic(resolved, repo, nextref);
560 	else
561 		*resolved = got_ref_dup(nextref);
562 
563 	got_ref_close(nextref);
564 	return err;
565 }
566 
567 static const struct got_error *
568 ref_resolve(struct got_object_id **id, struct got_repository *repo,
569     struct got_reference *ref, int recursion)
570 {
571 	const struct got_error *err;
572 
573 	if (recursion <= 0)
574 		return got_error_msg(GOT_ERR_RECURSION,
575 		    "reference recursion limit reached");
576 
577 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
578 		struct got_reference *resolved = NULL;
579 		err = got_ref_resolve_symbolic(&resolved, repo, ref);
580 		if (err == NULL)
581 			err = ref_resolve(id, repo, resolved, --recursion);
582 		if (resolved)
583 			got_ref_close(resolved);
584 		return err;
585 	}
586 
587 	*id = calloc(1, sizeof(**id));
588 	if (*id == NULL)
589 		return got_error_from_errno("calloc");
590 	memcpy(*id, &ref->ref.ref.id, sizeof(**id));
591 	return NULL;
592 }
593 
594 const struct got_error *
595 got_ref_resolve(struct got_object_id **id, struct got_repository *repo,
596     struct got_reference *ref)
597 {
598 	return ref_resolve(id, repo, ref, GOT_REF_RECURSE_MAX);
599 }
600 
601 char *
602 got_ref_to_str(struct got_reference *ref)
603 {
604 	char *str;
605 
606 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
607 		return strdup(ref->ref.symref.ref);
608 
609 	if (got_object_id_str(&str, &ref->ref.ref.id) != NULL)
610 		return NULL;
611 
612 	return str;
613 }
614 
615 const char *
616 got_ref_get_name(struct got_reference *ref)
617 {
618 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
619 		return ref->ref.symref.name;
620 
621 	return ref->ref.ref.name;
622 }
623 
624 const char *
625 got_ref_get_symref_target(struct got_reference *ref)
626 {
627 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
628 		return ref->ref.symref.ref;
629 
630 	return NULL;
631 }
632 
633 time_t
634 got_ref_get_mtime(struct got_reference *ref)
635 {
636 	return ref->mtime;
637 }
638 
639 const struct got_error *
640 got_ref_cmp_by_name(void *arg, int *cmp, struct got_reference *re1,
641     struct got_reference* re2)
642 {
643 	const char *name1 = got_ref_get_name(re1);
644 	const char *name2 = got_ref_get_name(re2);
645 
646 	*cmp = got_path_cmp(name1, name2, strlen(name1), strlen(name2));
647 	return NULL;
648 }
649 
650 const struct got_error *
651 got_ref_cmp_tags(void *arg, int *cmp, struct got_reference *ref1,
652     struct got_reference *ref2)
653 {
654 	const struct got_error *err = NULL;
655 	struct got_repository *repo = arg;
656 	struct got_object_id *id1, *id2 = NULL;
657 	struct got_tag_object *tag1 = NULL, *tag2 = NULL;
658 	struct got_commit_object *commit1 = NULL, *commit2 = NULL;
659 	time_t time1, time2;
660 
661 	*cmp = 0;
662 
663 	err = got_ref_resolve(&id1, repo, ref1);
664 	if (err)
665 		return err;
666 	err = got_object_open_as_tag(&tag1, repo, id1);
667 	if (err) {
668 		if (err->code != GOT_ERR_OBJ_TYPE)
669 			goto done;
670 		/* "lightweight" tag */
671 		err = got_object_open_as_commit(&commit1, repo, id1);
672 		if (err)
673 			goto done;
674 		time1 = got_object_commit_get_committer_time(commit1);
675 	} else
676 		time1 = got_object_tag_get_tagger_time(tag1);
677 
678 	err = got_ref_resolve(&id2, repo, ref2);
679 	if (err)
680 		goto done;
681 	err = got_object_open_as_tag(&tag2, repo, id2);
682 	if (err) {
683 		if (err->code != GOT_ERR_OBJ_TYPE)
684 			goto done;
685 		/* "lightweight" tag */
686 		err = got_object_open_as_commit(&commit2, repo, id2);
687 		if (err)
688 			goto done;
689 		time2 = got_object_commit_get_committer_time(commit2);
690 	} else
691 		time2 = got_object_tag_get_tagger_time(tag2);
692 
693 	/* Put latest tags first. */
694 	if (time1 < time2)
695 		*cmp = 1;
696 	else if (time1 > time2)
697 		*cmp = -1;
698 	else
699 		err = got_ref_cmp_by_name(NULL, cmp, ref2, ref1);
700 done:
701 	free(id1);
702 	free(id2);
703 	if (tag1)
704 		got_object_tag_close(tag1);
705 	if (tag2)
706 		got_object_tag_close(tag2);
707 	if (commit1)
708 		got_object_commit_close(commit1);
709 	if (commit2)
710 		got_object_commit_close(commit2);
711 	return err;
712 }
713 
714 static const struct got_error *
715 get_committer_time(struct got_reference *ref, struct got_repository *repo)
716 {
717 	const struct got_error *err = NULL;
718 	int obj_type;
719 	struct got_commit_object *commit = NULL;
720 	struct got_tag_object *tag = NULL;
721 	struct got_object_id *id = NULL;
722 
723 	err = got_ref_resolve(&id, repo, ref);
724 	if (err)
725 		return err;
726 
727 	err = got_object_get_type(&obj_type, repo, id);
728 	if (err)
729 		goto done;
730 
731 	switch (obj_type) {
732 	case GOT_OBJ_TYPE_COMMIT:
733 		err = got_object_open_as_commit(&commit, repo, id);
734 		if (err)
735 			goto done;
736 		ref->committer_time =
737 		    got_object_commit_get_committer_time(commit);
738 		break;
739 	case GOT_OBJ_TYPE_TAG:
740 		err = got_object_open_as_tag(&tag, repo, id);
741 		if (err)
742 			goto done;
743 		ref->committer_time = got_object_tag_get_tagger_time(tag);
744 		break;
745 	default:
746 		/* best effort for other object types */
747 		ref->committer_time = got_ref_get_mtime(ref);
748 		break;
749 	}
750 done:
751 	free(id);
752 	if (commit)
753 		got_object_commit_close(commit);
754 	if (tag)
755 		got_object_tag_close(tag);
756 	return err;
757 }
758 
759 const struct got_error *
760 got_ref_cmp_by_commit_timestamp_descending(void *arg, int *cmp,
761     struct got_reference *ref1, struct got_reference *ref2)
762 {
763 	const struct got_error *err = NULL;
764 	struct got_repository *repo = arg;
765 
766 	*cmp = 0;
767 
768 	if (ref1->committer_time == 0) {
769 		err = get_committer_time(ref1, repo);
770 		if (err)
771 			return err;
772 	}
773 	if (ref2->committer_time == 0) {
774 		err = get_committer_time(ref2, repo);
775 		if (err)
776 			return err;
777 	}
778 
779 	if (ref1->committer_time < ref2->committer_time)
780 		*cmp = 1;
781 	else if (ref2->committer_time < ref1->committer_time)
782 		*cmp = -1;
783 	else
784 		return got_ref_cmp_by_name(arg, cmp, ref1, ref2);
785 
786 	return err;
787 }
788 
789 const struct got_error *
790 got_reflist_insert(struct got_reflist_entry **newp,
791     struct got_reflist_head *refs, struct got_reference *ref,
792     got_ref_cmp_cb cmp_cb, void *cmp_arg)
793 {
794 	const struct got_error *err;
795 	struct got_reflist_entry *new, *re;
796 	int cmp;
797 
798 	*newp = NULL;
799 
800 	if (cmp_cb != got_ref_cmp_by_name && (ref->flags & GOT_REF_IS_PACKED)) {
801 		/*
802 		 * If we are not sorting elements by name then we must still
803 		 * detect collisions between a packed ref and an on-disk ref
804 		 * using the same name. On-disk refs take precedence and are
805 		 * already present on the list before packed refs get added.
806 		 */
807 		TAILQ_FOREACH(re, refs, entry) {
808 			err = got_ref_cmp_by_name(NULL, &cmp, re->ref, ref);
809 			if (err)
810 				return err;
811 			if (cmp == 0)
812 				return NULL;
813 		}
814 	}
815 
816 	new = malloc(sizeof(*new));
817 	if (new == NULL)
818 		return got_error_from_errno("malloc");
819 	new->ref = ref;
820 	*newp = new;
821 
822 	/*
823 	 * We must de-duplicate entries on insert because packed-refs may
824 	 * contain redundant entries. On-disk refs take precedence.
825 	 * This code assumes that on-disk revs are read before packed-refs.
826 	 * We're iterating the list anyway, so insert elements sorted by name.
827 	 *
828 	 * Many callers will provide paths in a somewhat sorted order.
829 	 * Iterating backwards from the tail of the list should be more
830 	 * efficient than traversing through the entire list each time
831 	 * an element is inserted.
832 	 */
833 	re = TAILQ_LAST(refs, got_reflist_head);
834 	while (re) {
835 		err = (*cmp_cb)(cmp_arg, &cmp, re->ref, new->ref);
836 		if (err)
837 			return err;
838 		if (cmp == 0) {
839 			/* duplicate */
840 			free(new);
841 			*newp = NULL;
842 			return NULL;
843 		} else if (cmp < 0) {
844 			TAILQ_INSERT_AFTER(refs, re, new, entry);
845 			return NULL;
846 		}
847 		re = TAILQ_PREV(re, got_reflist_head, entry);
848 	}
849 
850 	TAILQ_INSERT_HEAD(refs, new, entry);
851 	return NULL;
852 }
853 
854 const struct got_error *
855 got_reflist_sort(struct got_reflist_head *refs,
856     got_ref_cmp_cb cmp_cb, void *cmp_arg)
857 {
858 	const struct got_error *err = NULL;
859 	struct got_reflist_entry *re, *tmp, *new;
860 	struct got_reflist_head sorted;
861 
862 	TAILQ_INIT(&sorted);
863 
864 	TAILQ_FOREACH_SAFE(re, refs, entry, tmp) {
865 		struct got_reference *ref = re->ref;
866 		TAILQ_REMOVE(refs, re, entry);
867 		free(re);
868 		err = got_reflist_insert(&new, &sorted, ref, cmp_cb, cmp_arg);
869 		if (err || new == NULL /* duplicate */)
870 			got_ref_close(ref);
871 		if (err)
872 			return err;
873 	}
874 
875 	TAILQ_CONCAT(refs, &sorted, entry);
876 	return NULL;
877 }
878 
879 static const struct got_error *
880 gather_on_disk_refs(struct got_reflist_head *refs, const char *path_refs,
881     const char *subdir, struct got_repository *repo,
882     got_ref_cmp_cb cmp_cb, void *cmp_arg)
883 {
884 	const struct got_error *err = NULL;
885 	DIR *d = NULL;
886 	char *path_subdir;
887 
888 	while (subdir[0] == '/')
889 		subdir++;
890 
891 	if (asprintf(&path_subdir, "%s/%s", path_refs, subdir) == -1)
892 		return got_error_from_errno("asprintf");
893 
894 	d = opendir(path_subdir);
895 	if (d == NULL)
896 		goto done;
897 
898 	for (;;) {
899 		struct dirent *dent;
900 		struct got_reference *ref;
901 		char *child;
902 		int type;
903 
904 		dent = readdir(d);
905 		if (dent == NULL)
906 			break;
907 
908 		if (strcmp(dent->d_name, ".") == 0 ||
909 		    strcmp(dent->d_name, "..") == 0)
910 			continue;
911 
912 		err = got_path_dirent_type(&type, path_subdir, dent);
913 		if (err)
914 			break;
915 
916 		switch (type) {
917 		case DT_REG:
918 			err = open_ref(&ref, path_refs, subdir, dent->d_name,
919 			    0);
920 			if (err)
921 				goto done;
922 			if (ref) {
923 				struct got_reflist_entry *new;
924 				err = got_reflist_insert(&new, refs, ref,
925 				    cmp_cb, cmp_arg);
926 				if (err || new == NULL /* duplicate */)
927 					got_ref_close(ref);
928 				if (err)
929 					goto done;
930 			}
931 			break;
932 		case DT_DIR:
933 			if (asprintf(&child, "%s%s%s", subdir,
934 			    subdir[0] == '\0' ? "" : "/", dent->d_name) == -1) {
935 				err = got_error_from_errno("asprintf");
936 				break;
937 			}
938 			err = gather_on_disk_refs(refs, path_refs, child, repo,
939 			    cmp_cb, cmp_arg);
940 			free(child);
941 			break;
942 		default:
943 			break;
944 		}
945 	}
946 done:
947 	if (d)
948 		closedir(d);
949 	free(path_subdir);
950 	return err;
951 }
952 
953 const struct got_error *
954 got_ref_list(struct got_reflist_head *refs, struct got_repository *repo,
955     const char *ref_namespace, got_ref_cmp_cb cmp_cb, void *cmp_arg)
956 {
957 	const struct got_error *err;
958 	char *packed_refs_path = NULL, *path_refs = NULL;
959 	char *abs_namespace = NULL, *buf = NULL;
960 	const char *ondisk_ref_namespace = NULL;
961 	char *line = NULL;
962 	FILE *f = NULL;
963 	struct got_reference *ref;
964 	struct got_reflist_entry *new;
965 
966 	if (ref_namespace == NULL || ref_namespace[0] == '\0') {
967 		path_refs = get_refs_dir_path(repo, GOT_REF_HEAD);
968 		if (path_refs == NULL) {
969 			err = got_error_from_errno("get_refs_dir_path");
970 			goto done;
971 		}
972 		err = open_ref(&ref, path_refs, "", GOT_REF_HEAD, 0);
973 		if (err)
974 			goto done;
975 		err = got_reflist_insert(&new, refs, ref, cmp_cb, cmp_arg);
976 		if (err || new == NULL /* duplicate */)
977 			got_ref_close(ref);
978 		if (err && err->code != GOT_ERR_NOT_REF)
979 			goto done;
980 	} else {
981 		/* Try listing a single reference. */
982 		const char *refname = ref_namespace;
983 		path_refs = get_refs_dir_path(repo, refname);
984 		if (path_refs == NULL) {
985 			err = got_error_from_errno("get_refs_dir_path");
986 			goto done;
987 		}
988 		err = open_ref(&ref, path_refs, "", refname, 0);
989 		if (err) {
990 			if (err->code != GOT_ERR_NOT_REF)
991 				goto done;
992 			/* Try to look up references in a given namespace. */
993 		} else {
994 			err = got_reflist_insert(&new, refs, ref,
995 			    cmp_cb, cmp_arg);
996 			if (err || new == NULL /* duplicate */)
997 				got_ref_close(ref);
998 			return err;
999 		}
1000 	}
1001 
1002 	if (ref_namespace) {
1003 		size_t len;
1004 		/* Canonicalize the path to eliminate double-slashes if any. */
1005 		if (asprintf(&abs_namespace, "/%s", ref_namespace) == -1) {
1006 			err = got_error_from_errno("asprintf");
1007 			goto done;
1008 		}
1009 		len = strlen(abs_namespace) + 1;
1010 		buf = malloc(len);
1011 		if (buf == NULL) {
1012 			err = got_error_from_errno("malloc");
1013 			goto done;
1014 		}
1015 		err = got_canonpath(abs_namespace, buf, len);
1016 		if (err)
1017 			goto done;
1018 		ondisk_ref_namespace = buf;
1019 		while (ondisk_ref_namespace[0] == '/')
1020 			ondisk_ref_namespace++;
1021 		if (strncmp(ondisk_ref_namespace, "refs/", 5) == 0)
1022 			ondisk_ref_namespace += 5;
1023 		else if (strcmp(ondisk_ref_namespace, "refs") == 0)
1024 			ondisk_ref_namespace = "";
1025 	}
1026 
1027 	/* Gather on-disk refs before parsing packed-refs. */
1028 	free(path_refs);
1029 	path_refs = get_refs_dir_path(repo, "");
1030 	if (path_refs == NULL) {
1031 		err = got_error_from_errno("get_refs_dir_path");
1032 		goto done;
1033 	}
1034 	err = gather_on_disk_refs(refs, path_refs,
1035 	    ondisk_ref_namespace ? ondisk_ref_namespace : "", repo,
1036 	    cmp_cb, cmp_arg);
1037 	if (err)
1038 		goto done;
1039 
1040 	/*
1041 	 * The packed-refs file may contain redundant entries, in which
1042 	 * case on-disk refs take precedence.
1043 	 */
1044 	packed_refs_path = got_repo_get_path_packed_refs(repo);
1045 	if (packed_refs_path == NULL) {
1046 		err = got_error_from_errno("got_repo_get_path_packed_refs");
1047 		goto done;
1048 	}
1049 
1050 	f = fopen(packed_refs_path, "re");
1051 	if (f) {
1052 		size_t linesize = 0;
1053 		ssize_t linelen;
1054 		struct stat sb;
1055 
1056 		if (fstat(fileno(f), &sb) == -1) {
1057 			err = got_error_from_errno2("fstat", packed_refs_path);
1058 			goto done;
1059 		}
1060 		for (;;) {
1061 			linelen = getline(&line, &linesize, f);
1062 			if (linelen == -1) {
1063 				if (feof(f))
1064 					break;
1065 				err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
1066 				goto done;
1067 			}
1068 			if (linelen > 0 && line[linelen - 1] == '\n')
1069 				line[linelen - 1] = '\0';
1070 			err = parse_packed_ref_line(&ref, NULL, line,
1071 			    sb.st_mtime);
1072 			if (err)
1073 				goto done;
1074 			if (ref) {
1075 				if (ref_namespace) {
1076 					const char *name;
1077 					name = got_ref_get_name(ref);
1078 					if (!got_path_is_child(name,
1079 					    ref_namespace,
1080 					    strlen(ref_namespace))) {
1081 						got_ref_close(ref);
1082 						continue;
1083 					}
1084 				}
1085 				err = got_reflist_insert(&new, refs, ref,
1086 				    cmp_cb, cmp_arg);
1087 				if (err || new == NULL /* duplicate */)
1088 					got_ref_close(ref);
1089 				if (err)
1090 					goto done;
1091 			}
1092 		}
1093 	}
1094 done:
1095 	free(packed_refs_path);
1096 	free(abs_namespace);
1097 	free(buf);
1098 	free(line);
1099 	free(path_refs);
1100 	if (f && fclose(f) == EOF && err == NULL)
1101 		err = got_error_from_errno("fclose");
1102 	return err;
1103 }
1104 
1105 void
1106 got_ref_list_free(struct got_reflist_head *refs)
1107 {
1108 	struct got_reflist_entry *re;
1109 
1110 	while ((re = TAILQ_FIRST(refs))) {
1111 		TAILQ_REMOVE(refs, re, entry);
1112 		got_ref_close(re->ref);
1113 		free(re);
1114 	}
1115 }
1116 
1117 int
1118 got_ref_is_symbolic(struct got_reference *ref)
1119 {
1120 	return (ref->flags & GOT_REF_IS_SYMBOLIC);
1121 }
1122 
1123 const struct got_error *
1124 got_ref_change_ref(struct got_reference *ref, struct got_object_id *id)
1125 {
1126 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
1127 		return got_error(GOT_ERR_BAD_REF_TYPE);
1128 
1129 	memcpy(&ref->ref.ref.id, id, sizeof(ref->ref.ref.id));
1130 	return NULL;
1131 }
1132 
1133 const struct got_error *
1134 got_ref_change_symref(struct got_reference *ref, const char *refname)
1135 {
1136 	char *new_name;
1137 
1138 	if ((ref->flags & GOT_REF_IS_SYMBOLIC) == 0)
1139 		return got_error(GOT_ERR_BAD_REF_TYPE);
1140 
1141 	new_name = strdup(refname);
1142 	if (new_name == NULL)
1143 		return got_error_from_errno("strdup");
1144 
1145 	free(ref->ref.symref.ref);
1146 	ref->ref.symref.ref = new_name;
1147 	return NULL;
1148 }
1149 
1150 const struct got_error *
1151 got_ref_change_symref_to_ref(struct got_reference *symref,
1152     struct got_object_id *id)
1153 {
1154 	if ((symref->flags & GOT_REF_IS_SYMBOLIC) == 0)
1155 		return got_error(GOT_ERR_BAD_REF_TYPE);
1156 
1157 	symref->ref.ref.name = symref->ref.symref.name;
1158 	memcpy(&symref->ref.ref.id, id, sizeof(symref->ref.ref.id));
1159 	symref->flags &= ~GOT_REF_IS_SYMBOLIC;
1160 	return NULL;
1161 }
1162 
1163 const struct got_error *
1164 got_ref_write(struct got_reference *ref, struct got_repository *repo)
1165 {
1166 	const struct got_error *err = NULL, *unlock_err = NULL;
1167 	const char *name = got_ref_get_name(ref);
1168 	char *path_refs = NULL, *path = NULL, *tmppath = NULL;
1169 	struct got_lockfile *lf = NULL;
1170 	FILE *f = NULL;
1171 	size_t n;
1172 	struct stat sb;
1173 
1174 	path_refs = get_refs_dir_path(repo, name);
1175 	if (path_refs == NULL) {
1176 		err = got_error_from_errno2("get_refs_dir_path", name);
1177 		goto done;
1178 	}
1179 
1180 	if (asprintf(&path, "%s/%s", path_refs, name) == -1) {
1181 		err = got_error_from_errno("asprintf");
1182 		goto done;
1183 	}
1184 
1185 	err = got_opentemp_named(&tmppath, &f, path, "");
1186 	if (err) {
1187 		char *parent;
1188 		if (!(err->code == GOT_ERR_ERRNO && errno == ENOENT))
1189 			goto done;
1190 		err = got_path_dirname(&parent, path);
1191 		if (err)
1192 			goto done;
1193 		err = got_path_mkdir(parent);
1194 		free(parent);
1195 		if (err)
1196 			goto done;
1197 		err = got_opentemp_named(&tmppath, &f, path, "");
1198 		if (err)
1199 			goto done;
1200 	}
1201 
1202 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
1203 		n = fprintf(f, "ref: %s\n", ref->ref.symref.ref);
1204 		if (n != strlen(ref->ref.symref.ref) + 6) {
1205 			err = got_ferror(f, GOT_ERR_IO);
1206 			goto done;
1207 		}
1208 	} else {
1209 		char *hex;
1210 		size_t len;
1211 
1212 		err = got_object_id_str(&hex, &ref->ref.ref.id);
1213 		if (err)
1214 			goto done;
1215 		len = strlen(hex);
1216 		n = fprintf(f, "%s\n", hex);
1217 		free(hex);
1218 		if (n != len + 1) {
1219 			err = got_ferror(f, GOT_ERR_IO);
1220 			goto done;
1221 		}
1222 	}
1223 
1224 	if (ref->lf == NULL) {
1225 		err = got_lockfile_lock(&lf, path, -1);
1226 		if (err)
1227 			goto done;
1228 	}
1229 
1230 	/* XXX: check if old content matches our expectations? */
1231 
1232 	if (stat(path, &sb) != 0) {
1233 		if (errno != ENOENT) {
1234 			err = got_error_from_errno2("stat", path);
1235 			goto done;
1236 		}
1237 		sb.st_mode = GOT_DEFAULT_FILE_MODE;
1238 	}
1239 
1240 	if (fchmod(fileno(f), sb.st_mode) != 0) {
1241 		err = got_error_from_errno2("fchmod", tmppath);
1242 		goto done;
1243 	}
1244 
1245 	if (rename(tmppath, path) != 0) {
1246 		err = got_error_from_errno3("rename", tmppath, path);
1247 		goto done;
1248 	}
1249 	free(tmppath);
1250 	tmppath = NULL;
1251 
1252 	if (stat(path, &sb) == -1) {
1253 		err = got_error_from_errno2("stat", path);
1254 		goto done;
1255 	}
1256 	ref->mtime = sb.st_mtime;
1257 done:
1258 	if (ref->lf == NULL && lf)
1259 		unlock_err = got_lockfile_unlock(lf, -1);
1260 	if (f) {
1261 		if (fclose(f) == EOF && err == NULL)
1262 			err = got_error_from_errno("fclose");
1263 	}
1264 	free(path_refs);
1265 	free(path);
1266 	if (tmppath) {
1267 		if (unlink(tmppath) == -1 && err == NULL)
1268 			err = got_error_from_errno2("unlink", tmppath);
1269 		free(tmppath);
1270 	}
1271 	return err ? err : unlock_err;
1272 }
1273 
1274 static const struct got_error *
1275 delete_packed_ref(struct got_reference *delref, struct got_repository *repo)
1276 {
1277 	const struct got_error *err = NULL, *unlock_err = NULL;
1278 	struct got_lockfile *lf = NULL;
1279 	FILE *f = NULL, *tmpf = NULL;
1280 	char *line = NULL, *packed_refs_path, *tmppath = NULL;
1281 	size_t linesize = 0;
1282 	struct got_reflist_head refs;
1283 	int found_delref = 0;
1284 
1285 	/* The packed-refs file does not cotain symbolic references. */
1286 	if (delref->flags & GOT_REF_IS_SYMBOLIC)
1287 		return got_error(GOT_ERR_BAD_REF_DATA);
1288 
1289 	TAILQ_INIT(&refs);
1290 
1291 	packed_refs_path = got_repo_get_path_packed_refs(repo);
1292 	if (packed_refs_path == NULL)
1293 		return got_error_from_errno("got_repo_get_path_packed_refs");
1294 
1295 	err = got_opentemp_named(&tmppath, &tmpf, packed_refs_path, "");
1296 	if (err)
1297 		goto done;
1298 
1299 	if (delref->lf == NULL) {
1300 		err = got_lockfile_lock(&lf, packed_refs_path, -1);
1301 		if (err)
1302 			goto done;
1303 	}
1304 
1305 	f = fopen(packed_refs_path, "re");
1306 	if (f == NULL) {
1307 		err = got_error_from_errno2("fopen", packed_refs_path);
1308 		goto done;
1309 	}
1310 	for (;;) {
1311 		ssize_t linelen;
1312 		struct got_reference *ref;
1313 		struct got_reflist_entry *new;
1314 
1315 		linelen = getline(&line, &linesize, f);
1316 		if (linelen == -1) {
1317 			if (feof(f))
1318 				break;
1319 			err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
1320 			goto done;
1321 		}
1322 		if (linelen > 0 && line[linelen - 1] == '\n')
1323 			line[linelen - 1] = '\0';
1324 		err = parse_packed_ref_line(&ref, NULL, line, 0);
1325 		if (err)
1326 			goto done;
1327 		if (ref == NULL)
1328 			continue;
1329 
1330 		if (strcmp(ref->ref.ref.name, delref->ref.ref.name) == 0 &&
1331 		    got_object_id_cmp(&ref->ref.ref.id,
1332 		    &delref->ref.ref.id) == 0) {
1333 			found_delref = 1;
1334 			got_ref_close(ref);
1335 			continue;
1336 		}
1337 
1338 		err = got_reflist_insert(&new, &refs, ref,
1339 		    got_ref_cmp_by_name, NULL);
1340 		if (err || new == NULL /* duplicate */)
1341 			got_ref_close(ref);
1342 		if (err)
1343 			goto done;
1344 	}
1345 
1346 	if (found_delref) {
1347 		struct got_reflist_entry *re;
1348 		size_t n;
1349 		struct stat sb;
1350 
1351 		n = fprintf(tmpf, "%s\n", GOT_PACKED_REFS_HEADER);
1352 		if (n != sizeof(GOT_PACKED_REFS_HEADER)) {
1353 			err = got_ferror(f, GOT_ERR_IO);
1354 			goto done;
1355 		}
1356 
1357 		TAILQ_FOREACH(re, &refs, entry) {
1358 			char *hex;
1359 			size_t len;
1360 
1361 			err = got_object_id_str(&hex, &re->ref->ref.ref.id);
1362 			if (err)
1363 				goto done;
1364 			len = strlen(hex);
1365 			n = fprintf(tmpf, "%s ", hex);
1366 			free(hex);
1367 			if (n != len + 1) {
1368 				err = got_ferror(f, GOT_ERR_IO);
1369 				goto done;
1370 			}
1371 
1372 			n = fprintf(tmpf, "%s\n", re->ref->ref.ref.name);
1373 			if (n != strlen(re->ref->ref.ref.name) + 1) {
1374 				err = got_ferror(f, GOT_ERR_IO);
1375 				goto done;
1376 			}
1377 		}
1378 
1379 		if (fflush(tmpf) != 0) {
1380 			err = got_error_from_errno("fflush");
1381 			goto done;
1382 		}
1383 
1384 		if (fstat(fileno(f), &sb) != 0) {
1385 			if (errno != ENOENT) {
1386 				err = got_error_from_errno2("fstat",
1387 				    packed_refs_path);
1388 				goto done;
1389 			}
1390 			sb.st_mode = GOT_DEFAULT_FILE_MODE;
1391 		}
1392 
1393 		if (fchmod(fileno(tmpf), sb.st_mode) != 0) {
1394 			err = got_error_from_errno2("fchmod", tmppath);
1395 			goto done;
1396 		}
1397 
1398 		if (rename(tmppath, packed_refs_path) != 0) {
1399 			err = got_error_from_errno3("rename", tmppath,
1400 			    packed_refs_path);
1401 			goto done;
1402 		}
1403 		free(tmppath);
1404 		tmppath = NULL;
1405 	}
1406 done:
1407 	if (delref->lf == NULL && lf)
1408 		unlock_err = got_lockfile_unlock(lf, -1);
1409 	if (f) {
1410 		if (fclose(f) == EOF && err == NULL)
1411 			err = got_error_from_errno("fclose");
1412 	}
1413 	if (tmppath && unlink(tmppath) == -1 && err == NULL)
1414 		err = got_error_from_errno2("unlink", tmppath);
1415 	if (tmpf && fclose(tmpf) == EOF && err == NULL)
1416 		err = got_error_from_errno("fclose");
1417 	free(tmppath);
1418 	free(packed_refs_path);
1419 	free(line);
1420 	got_ref_list_free(&refs);
1421 	return err ? err : unlock_err;
1422 }
1423 
1424 static const struct got_error *
1425 delete_loose_ref(struct got_reference *ref, struct got_repository *repo)
1426 {
1427 	const struct got_error *err = NULL, *unlock_err = NULL;
1428 	const char *name = got_ref_get_name(ref);
1429 	char *path_refs = NULL, *path = NULL;
1430 	struct got_lockfile *lf = NULL;
1431 
1432 	path_refs = get_refs_dir_path(repo, name);
1433 	if (path_refs == NULL) {
1434 		err = got_error_from_errno2("get_refs_dir_path", name);
1435 		goto done;
1436 	}
1437 
1438 	if (asprintf(&path, "%s/%s", path_refs, name) == -1) {
1439 		err = got_error_from_errno("asprintf");
1440 		goto done;
1441 	}
1442 
1443 	if (ref->lf == NULL) {
1444 		err = got_lockfile_lock(&lf, path, -1);
1445 		if (err)
1446 			goto done;
1447 	}
1448 
1449 	/* XXX: check if old content matches our expectations? */
1450 
1451 	if (unlink(path) == -1)
1452 		err = got_error_from_errno2("unlink", path);
1453 done:
1454 	if (ref->lf == NULL && lf)
1455 		unlock_err = got_lockfile_unlock(lf, -1);
1456 
1457 	free(path_refs);
1458 	free(path);
1459 	return err ? err : unlock_err;
1460 }
1461 
1462 const struct got_error *
1463 got_ref_delete(struct got_reference *ref, struct got_repository *repo)
1464 {
1465 	const struct got_error *err = NULL;
1466 	struct got_reference *ref2;
1467 
1468 	if (ref->flags & GOT_REF_IS_PACKED) {
1469 		err = delete_packed_ref(ref, repo);
1470 		if (err)
1471 			return err;
1472 
1473 		err = got_ref_open(&ref2, repo, got_ref_get_name(ref), 0);
1474 		if (err) {
1475 			if (err->code == GOT_ERR_NOT_REF)
1476 				return NULL;
1477 			return err;
1478 		}
1479 
1480 		err = delete_loose_ref(ref2, repo);
1481 		got_ref_close(ref2);
1482 		return err;
1483 	} else {
1484 		err = delete_loose_ref(ref, repo);
1485 		if (err)
1486 			return err;
1487 
1488 		err = got_ref_open(&ref2, repo, got_ref_get_name(ref), 0);
1489 		if (err) {
1490 			if (err->code == GOT_ERR_NOT_REF)
1491 				return NULL;
1492 			return err;
1493 		}
1494 
1495 		err = delete_packed_ref(ref2, repo);
1496 		got_ref_close(ref2);
1497 		return err;
1498 	}
1499 }
1500 
1501 const struct got_error *
1502 got_ref_unlock(struct got_reference *ref)
1503 {
1504 	const struct got_error *err;
1505 	err = got_lockfile_unlock(ref->lf, -1);
1506 	ref->lf = NULL;
1507 	return err;
1508 }
1509 
1510 struct got_reflist_object_id_map {
1511 	struct got_object_idset *idset;
1512 };
1513 
1514 struct got_reflist_object_id_map_entry {
1515 	struct got_reflist_head refs;
1516 };
1517 
1518 static const struct got_error *
1519 add_object_id_map_entry(struct got_object_idset *idset,
1520     struct got_object_id *id, struct got_reflist_entry *re)
1521 {
1522 	const struct got_error *err = NULL;
1523 	struct got_reflist_object_id_map_entry *ent;
1524 	struct got_reflist_entry *new;
1525 
1526 	ent = got_object_idset_get(idset, id);
1527 	if (ent == NULL) {
1528 		ent = malloc(sizeof(*ent));
1529 		if (ent == NULL)
1530 			return got_error_from_errno("malloc");
1531 
1532 		TAILQ_INIT(&ent->refs);
1533 		err = got_object_idset_add(idset, id, ent);
1534 		if (err) {
1535 			free(ent);
1536 			return err;
1537 		}
1538 	}
1539 
1540 	err = got_reflist_entry_dup(&new, re);
1541 	if (err)
1542 		return err;
1543 
1544 	TAILQ_INSERT_TAIL(&ent->refs, new, entry);
1545 	return NULL;
1546 }
1547 
1548 const struct got_error *
1549 got_reflist_object_id_map_create(struct got_reflist_object_id_map **map,
1550     struct got_reflist_head *refs, struct got_repository *repo)
1551 {
1552 	const struct got_error *err = NULL;
1553 	struct got_object_idset *idset;
1554 	struct got_object_id *id = NULL;
1555 	struct got_reflist_entry *re;
1556 
1557 	idset = got_object_idset_alloc();
1558 	if (idset == NULL)
1559 		return got_error_from_errno("got_object_idset_alloc");
1560 
1561 	*map = malloc(sizeof(**map));
1562 	if (*map == NULL) {
1563 		got_object_idset_free(idset);
1564 		return got_error_from_errno("malloc");
1565 	}
1566 	(*map)->idset = idset;
1567 
1568 	TAILQ_FOREACH(re, refs, entry) {
1569 		struct got_tag_object *tag = NULL;
1570 
1571 		err = got_ref_resolve(&id, repo, re->ref);
1572 		if (err)
1573 			goto done;
1574 
1575 		err = add_object_id_map_entry(idset, id, re);
1576 		if (err)
1577 			goto done;
1578 
1579 		if (strstr(got_ref_get_name(re->ref), "/tags/") == NULL) {
1580 			free(id);
1581 			id = NULL;
1582 			continue;
1583 		}
1584 
1585 		err = got_object_open_as_tag(&tag, repo, id);
1586 		if (err) {
1587 			if (err->code != GOT_ERR_OBJ_TYPE)
1588 				goto done;
1589 			/* Ref points at something other than a tag. */
1590 			err = NULL;
1591 			tag = NULL;
1592 			free(id);
1593 			id = NULL;
1594 			continue;
1595 		}
1596 
1597 		err = add_object_id_map_entry(idset,
1598 		    got_object_tag_get_object_id(tag), re);
1599 		got_object_tag_close(tag);
1600 		if (err)
1601 			goto done;
1602 
1603 		free(id);
1604 		id = NULL;
1605 	}
1606 done:
1607 	free(id);
1608 	if (err) {
1609 		got_reflist_object_id_map_free(*map);
1610 		*map = NULL;
1611 	}
1612 	return err;
1613 }
1614 
1615 struct got_reflist_head *
1616 got_reflist_object_id_map_lookup(struct got_reflist_object_id_map *map,
1617     struct got_object_id *id)
1618 {
1619 	struct got_reflist_object_id_map_entry *ent;
1620 	ent = got_object_idset_get(map->idset, id);
1621 	if (ent)
1622 		return &ent->refs;
1623 	return NULL;
1624 }
1625 
1626 static const struct got_error *
1627 free_id_map_entry(struct got_object_id *id, void *data, void *arg)
1628 {
1629 	struct got_reflist_object_id_map_entry *ent = data;
1630 
1631 	got_ref_list_free(&ent->refs);
1632 	free(ent);
1633 	return NULL;
1634 }
1635 
1636 void
1637 got_reflist_object_id_map_free(struct got_reflist_object_id_map *map)
1638 {
1639 	got_object_idset_for_each(map->idset, free_id_map_entry, NULL);
1640 	got_object_idset_free(map->idset);
1641 	free(map);
1642 }