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Date:: Thu Apr 14 09:51:32 2022 UTC
Message:: make sure callers of got_object_idset_add() free data.
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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 <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 	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.sha1, id->sha1, sizeof((*ref)->ref.ref.sha1));
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 int
272 got_ref_name_is_valid(const char *name)
273 {
274 	const char *s, *seg;
275 	const char forbidden[] = { ' ', '~', '^', ':', '?', '*', '[' , '\\' };
276 	const char *forbidden_seq[] = { "//", "..", "@{" };
277 	const char *lfs = GOT_LOCKFILE_SUFFIX;
278 	const size_t lfs_len = sizeof(GOT_LOCKFILE_SUFFIX) - 1;
279 	size_t i;
280 
281 	if (name[0] == '@' && name[1] == '\0')
282 		return 0;
283 
284 	s = name;
285 	seg = s;
286 	if (seg[0] == '\0' || seg[0] == '.' || seg[0] == '/')
287 		return 0;
288 	while (*s) {
289 		for (i = 0; i < nitems(forbidden); i++) {
290 			if (*s == forbidden[i])
291 				return 0;
292 		}
293 		for (i = 0; i < nitems(forbidden_seq); i++) {
294 			if (s[0] == forbidden_seq[i][0] &&
295 			    s[1] == forbidden_seq[i][1])
296 				return 0;
297 		}
298 		if (iscntrl((unsigned char)s[0]))
299 			return 0;
300 		if (s[0] == '.' && s[1] == '\0')
301 			return 0;
302 		if (*s == '/') {
303 			const char *nextseg = s + 1;
304 			if (nextseg[0] == '\0' || nextseg[0] == '.' ||
305 			    nextseg[0] == '/')
306 				return 0;
307 			if (seg <= s - lfs_len &&
308 			    strncmp(s - lfs_len, lfs, lfs_len) == 0)
309 				return 0;
310 			seg = nextseg;
311 		}
312 		s++;
313 	}
314 
315 	if (seg <= s - lfs_len &&
316 	    strncmp(s - lfs_len, lfs, lfs_len) == 0)
317 		return 0;
318 
319 	return 1;
320 }
321 
322 const struct got_error *
323 got_ref_alloc(struct got_reference **ref, const char *name,
324     struct got_object_id *id)
325 {
326 	if (!got_ref_name_is_valid(name))
327 		return got_error_path(name, GOT_ERR_BAD_REF_NAME);
328 
329 	return alloc_ref(ref, name, id, 0, 0);
330 }
331 
332 const struct got_error *
333 got_ref_alloc_symref(struct got_reference **ref, const char *name,
334 	struct got_reference *target_ref)
335 {
336 	if (!got_ref_name_is_valid(name))
337 		return got_error_path(name, GOT_ERR_BAD_REF_NAME);
338 
339 	return alloc_symref(ref, name, got_ref_get_name(target_ref), 0);
340 }
341 
342 static const struct got_error *
343 parse_packed_ref_line(struct got_reference **ref, const char *abs_refname,
344     const char *line, time_t mtime)
345 {
346 	struct got_object_id id;
347 	const char *name;
348 
349 	*ref = NULL;
350 
351 	if (line[0] == '#' || line[0] == '^')
352 		return NULL;
353 
354 	if (!got_parse_sha1_digest(id.sha1, line))
355 		return got_error(GOT_ERR_BAD_REF_DATA);
356 
357 	if (abs_refname) {
358 		if (strcmp(line + SHA1_DIGEST_STRING_LENGTH, abs_refname) != 0)
359 			return NULL;
360 		name = abs_refname;
361 	} else
362 		name = line + SHA1_DIGEST_STRING_LENGTH;
363 
364 	return alloc_ref(ref, name, &id, GOT_REF_IS_PACKED, mtime);
365 }
366 
367 static const struct got_error *
368 open_packed_ref(struct got_reference **ref, FILE *f, const char **subdirs,
369     int nsubdirs, const char *refname, time_t mtime)
370 {
371 	const struct got_error *err = NULL;
372 	char *abs_refname;
373 	char *line = NULL;
374 	size_t linesize = 0;
375 	ssize_t linelen;
376 	int i, ref_is_absolute = (strncmp(refname, "refs/", 5) == 0);
377 
378 	*ref = NULL;
379 
380 	if (ref_is_absolute)
381 		abs_refname = (char *)refname;
382 	do {
383 		linelen = getline(&line, &linesize, f);
384 		if (linelen == -1) {
385 			if (feof(f))
386 				break;
387 			err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
388 			break;
389 		}
390 		if (linelen > 0 && line[linelen - 1] == '\n')
391 			line[linelen - 1] = '\0';
392 		for (i = 0; i < nsubdirs; i++) {
393 			if (!ref_is_absolute &&
394 			    asprintf(&abs_refname, "refs/%s/%s", subdirs[i],
395 			    refname) == -1)
396 				return got_error_from_errno("asprintf");
397 			err = parse_packed_ref_line(ref, abs_refname, line,
398 			    mtime);
399 			if (!ref_is_absolute)
400 				free(abs_refname);
401 			if (err || *ref != NULL)
402 				break;
403 		}
404 		if (err)
405 			break;
406 	} while (*ref == NULL);
407 	free(line);
408 
409 	return err;
410 }
411 
412 static const struct got_error *
413 open_ref(struct got_reference **ref, const char *path_refs, const char *subdir,
414     const char *name, int lock)
415 {
416 	const struct got_error *err = NULL;
417 	char *path = NULL;
418 	char *absname = NULL;
419 	int ref_is_absolute = (strncmp(name, "refs/", 5) == 0);
420 	int ref_is_well_known = (subdir[0] == '\0' && is_well_known_ref(name));
421 
422 	*ref = NULL;
423 
424 	if (!got_ref_name_is_valid(name))
425 		return got_error_path(name, GOT_ERR_BAD_REF_NAME);
426 
427 	if (ref_is_absolute || ref_is_well_known) {
428 		if (asprintf(&path, "%s/%s", path_refs, name) == -1)
429 			return got_error_from_errno("asprintf");
430 		absname = (char *)name;
431 	} else {
432 		if (asprintf(&path, "%s/%s%s%s", path_refs, subdir,
433 		    subdir[0] ? "/" : "", name) == -1)
434 			return got_error_from_errno("asprintf");
435 
436 		if (asprintf(&absname, "refs/%s%s%s",
437 		    subdir, subdir[0] ? "/" : "", name) == -1) {
438 			err = got_error_from_errno("asprintf");
439 			goto done;
440 		}
441 	}
442 
443 	err = parse_ref_file(ref, name, absname, path, lock);
444 done:
445 	if (!ref_is_absolute && !ref_is_well_known)
446 		free(absname);
447 	free(path);
448 	return err;
449 }
450 
451 const struct got_error *
452 got_ref_open(struct got_reference **ref, struct got_repository *repo,
453     const char *refname, int lock)
454 {
455 	const struct got_error *err = NULL;
456 	char *path_refs = NULL;
457 	const char *subdirs[] = {
458 	    GOT_REF_HEADS, GOT_REF_TAGS, GOT_REF_REMOTES
459 	};
460 	size_t i;
461 	int well_known = is_well_known_ref(refname);
462 	struct got_lockfile *lf = NULL;
463 
464 	*ref = NULL;
465 
466 	path_refs = get_refs_dir_path(repo, refname);
467 	if (path_refs == NULL) {
468 		err = got_error_from_errno2("get_refs_dir_path", refname);
469 		goto done;
470 	}
471 
472 	if (well_known) {
473 		err = open_ref(ref, path_refs, "", refname, lock);
474 	} else {
475 		char *packed_refs_path;
476 		FILE *f;
477 
478 		/* Search on-disk refs before packed refs! */
479 		for (i = 0; i < nitems(subdirs); i++) {
480 			err = open_ref(ref, path_refs, subdirs[i], refname,
481 			    lock);
482 			if ((err && err->code != GOT_ERR_NOT_REF) || *ref)
483 				goto done;
484 		}
485 
486 		packed_refs_path = got_repo_get_path_packed_refs(repo);
487 		if (packed_refs_path == NULL) {
488 			err = got_error_from_errno(
489 			    "got_repo_get_path_packed_refs");
490 			goto done;
491 		}
492 
493 		if (lock) {
494 			err = got_lockfile_lock(&lf, packed_refs_path, -1);
495 			if (err)
496 				goto done;
497 		}
498 		f = fopen(packed_refs_path, "rbe");
499 		free(packed_refs_path);
500 		if (f != NULL) {
501 			struct stat sb;
502 			if (fstat(fileno(f), &sb) == -1) {
503 				err = got_error_from_errno2("fstat",
504 				    packed_refs_path);
505 				goto done;
506 			}
507 			err = open_packed_ref(ref, f, subdirs, nitems(subdirs),
508 			    refname, sb.st_mtime);
509 			if (!err) {
510 				if (fclose(f) == EOF) {
511 					err = got_error_from_errno("fclose");
512 					got_ref_close(*ref);
513 					*ref = NULL;
514 				} else if (*ref)
515 					(*ref)->lf = lf;
516 			}
517 		}
518 	}
519 done:
520 	if (!err && *ref == NULL)
521 		err = got_error_not_ref(refname);
522 	if (err && lf)
523 		got_lockfile_unlock(lf, -1);
524 	free(path_refs);
525 	return err;
526 }
527 
528 void
529 got_ref_close(struct got_reference *ref)
530 {
531 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
532 		free(ref->ref.symref.name);
533 		free(ref->ref.symref.ref);
534 	} else
535 		free(ref->ref.ref.name);
536 	free(ref);
537 }
538 
539 struct got_reference *
540 got_ref_dup(struct got_reference *ref)
541 {
542 	struct got_reference *ret;
543 
544 	ret = calloc(1, sizeof(*ret));
545 	if (ret == NULL)
546 		return NULL;
547 
548 	ret->flags = ref->flags;
549 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
550 		ret->ref.symref.name = strdup(ref->ref.symref.name);
551 		if (ret->ref.symref.name == NULL) {
552 			free(ret);
553 			return NULL;
554 		}
555 		ret->ref.symref.ref = strdup(ref->ref.symref.ref);
556 		if (ret->ref.symref.ref == NULL) {
557 			free(ret->ref.symref.name);
558 			free(ret);
559 			return NULL;
560 		}
561 	} else {
562 		ret->ref.ref.name = strdup(ref->ref.ref.name);
563 		if (ret->ref.ref.name == NULL) {
564 			free(ret);
565 			return NULL;
566 		}
567 		memcpy(ret->ref.ref.sha1, ref->ref.ref.sha1,
568 		    sizeof(ret->ref.ref.sha1));
569 	}
570 
571 	return ret;
572 }
573 
574 const struct got_error *
575 got_reflist_entry_dup(struct got_reflist_entry **newp,
576     struct got_reflist_entry *re)
577 {
578 	const struct got_error *err = NULL;
579 	struct got_reflist_entry *new;
580 
581 	*newp = NULL;
582 
583 	new = malloc(sizeof(*new));
584 	if (new == NULL)
585 		return got_error_from_errno("malloc");
586 
587 	new->ref = got_ref_dup(re->ref);
588 	if (new->ref == NULL) {
589 		err = got_error_from_errno("got_ref_dup");
590 		free(new);
591 		return err;
592 	}
593 
594 	*newp = new;
595 	return NULL;
596 }
597 
598 const struct got_error *
599 got_ref_resolve_symbolic(struct got_reference **resolved,
600     struct got_repository *repo, struct got_reference *ref)
601 {
602 	struct got_reference *nextref;
603 	const struct got_error *err;
604 
605 	err = got_ref_open(&nextref, repo, ref->ref.symref.ref, 0);
606 	if (err)
607 		return err;
608 
609 	if (nextref->flags & GOT_REF_IS_SYMBOLIC)
610 		err = got_ref_resolve_symbolic(resolved, repo, nextref);
611 	else
612 		*resolved = got_ref_dup(nextref);
613 
614 	got_ref_close(nextref);
615 	return err;
616 }
617 
618 static const struct got_error *
619 ref_resolve(struct got_object_id **id, struct got_repository *repo,
620     struct got_reference *ref, int recursion)
621 {
622 	const struct got_error *err;
623 
624 	if (recursion <= 0)
625 		return got_error_msg(GOT_ERR_RECURSION,
626 		    "reference recursion limit reached");
627 
628 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
629 		struct got_reference *resolved = NULL;
630 		err = got_ref_resolve_symbolic(&resolved, repo, ref);
631 		if (err == NULL)
632 			err = ref_resolve(id, repo, resolved, --recursion);
633 		if (resolved)
634 			got_ref_close(resolved);
635 		return err;
636 	}
637 
638 	*id = calloc(1, sizeof(**id));
639 	if (*id == NULL)
640 		return got_error_from_errno("calloc");
641 	memcpy((*id)->sha1, ref->ref.ref.sha1, sizeof((*id)->sha1));
642 	return NULL;
643 }
644 
645 const struct got_error *
646 got_ref_resolve(struct got_object_id **id, struct got_repository *repo,
647     struct got_reference *ref)
648 {
649 	return ref_resolve(id, repo, ref, GOT_REF_RECURSE_MAX);
650 }
651 
652 char *
653 got_ref_to_str(struct got_reference *ref)
654 {
655 	char *str;
656 
657 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
658 		return strdup(ref->ref.symref.ref);
659 
660 	str = malloc(SHA1_DIGEST_STRING_LENGTH);
661 	if (str == NULL)
662 		return NULL;
663 
664 	if (got_sha1_digest_to_str(ref->ref.ref.sha1, str,
665 	    SHA1_DIGEST_STRING_LENGTH) == NULL) {
666 		free(str);
667 		return NULL;
668 	}
669 
670 	return str;
671 }
672 
673 const char *
674 got_ref_get_name(struct got_reference *ref)
675 {
676 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
677 		return ref->ref.symref.name;
678 
679 	return ref->ref.ref.name;
680 }
681 
682 const char *
683 got_ref_get_symref_target(struct got_reference *ref)
684 {
685 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
686 		return ref->ref.symref.ref;
687 
688 	return NULL;
689 }
690 
691 time_t
692 got_ref_get_mtime(struct got_reference *ref)
693 {
694 	return ref->mtime;
695 }
696 
697 const struct got_error *
698 got_ref_cmp_by_name(void *arg, int *cmp, struct got_reference *re1,
699     struct got_reference* re2)
700 {
701 	const char *name1 = got_ref_get_name(re1);
702 	const char *name2 = got_ref_get_name(re2);
703 
704 	*cmp = got_path_cmp(name1, name2, strlen(name1), strlen(name2));
705 	return NULL;
706 }
707 
708 const struct got_error *
709 got_ref_cmp_tags(void *arg, int *cmp, struct got_reference *ref1,
710     struct got_reference *ref2)
711 {
712 	const struct got_error *err = NULL;
713 	struct got_repository *repo = arg;
714 	struct got_object_id *id1, *id2 = NULL;
715 	struct got_tag_object *tag1 = NULL, *tag2 = NULL;
716 	struct got_commit_object *commit1 = NULL, *commit2 = NULL;
717 	time_t time1, time2;
718 
719 	*cmp = 0;
720 
721 	err = got_ref_resolve(&id1, repo, ref1);
722 	if (err)
723 		return err;
724 	err = got_object_open_as_tag(&tag1, repo, id1);
725 	if (err) {
726 		if (err->code != GOT_ERR_OBJ_TYPE)
727 			goto done;
728 		/* "lightweight" tag */
729 		err = got_object_open_as_commit(&commit1, repo, id1);
730 		if (err)
731 			goto done;
732 		time1 = got_object_commit_get_committer_time(commit1);
733 	} else
734 		time1 = got_object_tag_get_tagger_time(tag1);
735 
736 	err = got_ref_resolve(&id2, repo, ref2);
737 	if (err)
738 		goto done;
739 	err = got_object_open_as_tag(&tag2, repo, id2);
740 	if (err) {
741 		if (err->code != GOT_ERR_OBJ_TYPE)
742 			goto done;
743 		/* "lightweight" tag */
744 		err = got_object_open_as_commit(&commit2, repo, id2);
745 		if (err)
746 			goto done;
747 		time2 = got_object_commit_get_committer_time(commit2);
748 	} else
749 		time2 = got_object_tag_get_tagger_time(tag2);
750 
751 	/* Put latest tags first. */
752 	if (time1 < time2)
753 		*cmp = 1;
754 	else if (time1 > time2)
755 		*cmp = -1;
756 	else
757 		err = got_ref_cmp_by_name(NULL, cmp, ref2, ref1);
758 done:
759 	free(id1);
760 	free(id2);
761 	if (tag1)
762 		got_object_tag_close(tag1);
763 	if (tag2)
764 		got_object_tag_close(tag2);
765 	if (commit1)
766 		got_object_commit_close(commit1);
767 	if (commit2)
768 		got_object_commit_close(commit2);
769 	return err;
770 }
771 
772 static const struct got_error *
773 get_committer_time(struct got_reference *ref, struct got_repository *repo)
774 {
775 	const struct got_error *err = NULL;
776 	int obj_type;
777 	struct got_commit_object *commit = NULL;
778 	struct got_tag_object *tag = NULL;
779 	struct got_object_id *id = NULL;
780 
781 	err = got_ref_resolve(&id, repo, ref);
782 	if (err)
783 		return err;
784 
785 	err = got_object_get_type(&obj_type, repo, id);
786 	if (err)
787 		goto done;
788 
789 	switch (obj_type) {
790 	case GOT_OBJ_TYPE_COMMIT:
791 		err = got_object_open_as_commit(&commit, repo, id);
792 		if (err)
793 			goto done;
794 		ref->committer_time =
795 		    got_object_commit_get_committer_time(commit);
796 		break;
797 	case GOT_OBJ_TYPE_TAG:
798 		err = got_object_open_as_tag(&tag, repo, id);
799 		if (err)
800 			goto done;
801 		ref->committer_time = got_object_tag_get_tagger_time(tag);
802 		break;
803 	default:
804 		/* best effort for other object types */
805 		ref->committer_time = got_ref_get_mtime(ref);
806 		break;
807 	}
808 done:
809 	free(id);
810 	if (commit)
811 		got_object_commit_close(commit);
812 	if (tag)
813 		got_object_tag_close(tag);
814 	return err;
815 }
816 
817 const struct got_error *
818 got_ref_cmp_by_commit_timestamp_descending(void *arg, int *cmp,
819     struct got_reference *ref1, struct got_reference *ref2)
820 {
821 	const struct got_error *err = NULL;
822 	struct got_repository *repo = arg;
823 
824 	*cmp = 0;
825 
826 	if (ref1->committer_time == 0) {
827 		err = get_committer_time(ref1, repo);
828 		if (err)
829 			return err;
830 	}
831 	if (ref2->committer_time == 0) {
832 		err = get_committer_time(ref2, repo);
833 		if (err)
834 			return err;
835 	}
836 
837 	if (ref1->committer_time < ref2->committer_time)
838 		*cmp = 1;
839 	else if (ref2->committer_time < ref1->committer_time)
840 		*cmp = -1;
841 	else
842 		return got_ref_cmp_by_name(arg, cmp, ref1, ref2);
843 
844 	return err;
845 }
846 
847 const struct got_error *
848 got_reflist_insert(struct got_reflist_entry **newp,
849     struct got_reflist_head *refs, struct got_reference *ref,
850     got_ref_cmp_cb cmp_cb, void *cmp_arg)
851 {
852 	const struct got_error *err;
853 	struct got_reflist_entry *new, *re;
854 	int cmp;
855 
856 	*newp = NULL;
857 
858 	new = malloc(sizeof(*new));
859 	if (new == NULL)
860 		return got_error_from_errno("malloc");
861 	new->ref = ref;
862 	*newp = new;
863 
864 	/*
865 	 * We must de-duplicate entries on insert because packed-refs may
866 	 * contain redundant entries. On-disk refs take precedence.
867 	 * This code assumes that on-disk revs are read before packed-refs.
868 	 * We're iterating the list anyway, so insert elements sorted by name.
869 	 *
870 	 * Many callers will provide paths in a somewhat sorted order.
871 	 * Iterating backwards from the tail of the list should be more
872 	 * efficient than traversing through the entire list each time
873 	 * an element is inserted.
874 	 */
875 	re = TAILQ_LAST(refs, got_reflist_head);
876 	while (re) {
877 		err = (*cmp_cb)(cmp_arg, &cmp, re->ref, new->ref);
878 		if (err)
879 			return err;
880 		if (cmp == 0) {
881 			/* duplicate */
882 			free(new);
883 			*newp = NULL;
884 			return NULL;
885 		} else if (cmp < 0) {
886 			TAILQ_INSERT_AFTER(refs, re, new, entry);
887 			return NULL;
888 		}
889 		re = TAILQ_PREV(re, got_reflist_head, entry);
890 	}
891 
892 	TAILQ_INSERT_HEAD(refs, new, entry);
893 	return NULL;
894 }
895 
896 const struct got_error *
897 got_reflist_sort(struct got_reflist_head *refs,
898     got_ref_cmp_cb cmp_cb, void *cmp_arg)
899 {
900 	const struct got_error *err = NULL;
901 	struct got_reflist_entry *re, *tmp, *new;
902 	struct got_reflist_head sorted;
903 
904 	TAILQ_INIT(&sorted);
905 
906 	TAILQ_FOREACH_SAFE(re, refs, entry, tmp) {
907 		struct got_reference *ref = re->ref;
908 		TAILQ_REMOVE(refs, re, entry);
909 		free(re);
910 		err = got_reflist_insert(&new, &sorted, ref, cmp_cb, cmp_arg);
911 		if (err || new == NULL /* duplicate */)
912 			got_ref_close(ref);
913 		if (err)
914 			return err;
915 	}
916 
917 	TAILQ_CONCAT(refs, &sorted, entry);
918 	return NULL;
919 }
920 
921 static const struct got_error *
922 gather_on_disk_refs(struct got_reflist_head *refs, const char *path_refs,
923     const char *subdir, struct got_repository *repo,
924     got_ref_cmp_cb cmp_cb, void *cmp_arg)
925 {
926 	const struct got_error *err = NULL;
927 	DIR *d = NULL;
928 	char *path_subdir;
929 
930 	while (subdir[0] == '/')
931 		subdir++;
932 
933 	if (asprintf(&path_subdir, "%s/%s", path_refs, subdir) == -1)
934 		return got_error_from_errno("asprintf");
935 
936 	d = opendir(path_subdir);
937 	if (d == NULL)
938 		goto done;
939 
940 	for (;;) {
941 		struct dirent *dent;
942 		struct got_reference *ref;
943 		char *child;
944 		int type;
945 
946 		dent = readdir(d);
947 		if (dent == NULL)
948 			break;
949 
950 		if (strcmp(dent->d_name, ".") == 0 ||
951 		    strcmp(dent->d_name, "..") == 0)
952 			continue;
953 
954 		err = got_path_dirent_type(&type, path_subdir, dent);
955 		if (err)
956 			break;
957 
958 		switch (type) {
959 		case DT_REG:
960 			err = open_ref(&ref, path_refs, subdir, dent->d_name,
961 			    0);
962 			if (err)
963 				goto done;
964 			if (ref) {
965 				struct got_reflist_entry *new;
966 				err = got_reflist_insert(&new, refs, ref,
967 				    cmp_cb, cmp_arg);
968 				if (err || new == NULL /* duplicate */)
969 					got_ref_close(ref);
970 				if (err)
971 					goto done;
972 			}
973 			break;
974 		case DT_DIR:
975 			if (asprintf(&child, "%s%s%s", subdir,
976 			    subdir[0] == '\0' ? "" : "/", dent->d_name) == -1) {
977 				err = got_error_from_errno("asprintf");
978 				break;
979 			}
980 			err = gather_on_disk_refs(refs, path_refs, child, repo,
981 			    cmp_cb, cmp_arg);
982 			free(child);
983 			break;
984 		default:
985 			break;
986 		}
987 	}
988 done:
989 	if (d)
990 		closedir(d);
991 	free(path_subdir);
992 	return err;
993 }
994 
995 const struct got_error *
996 got_ref_list(struct got_reflist_head *refs, struct got_repository *repo,
997     const char *ref_namespace, got_ref_cmp_cb cmp_cb, void *cmp_arg)
998 {
999 	const struct got_error *err;
1000 	char *packed_refs_path, *path_refs = NULL;
1001 	char *abs_namespace = NULL;
1002 	char *buf = NULL, *ondisk_ref_namespace = NULL;
1003 	char *line = NULL;
1004 	FILE *f = NULL;
1005 	struct got_reference *ref;
1006 	struct got_reflist_entry *new;
1007 
1008 	if (ref_namespace == NULL || ref_namespace[0] == '\0') {
1009 		path_refs = get_refs_dir_path(repo, GOT_REF_HEAD);
1010 		if (path_refs == NULL) {
1011 			err = got_error_from_errno("get_refs_dir_path");
1012 			goto done;
1013 		}
1014 		err = open_ref(&ref, path_refs, "", GOT_REF_HEAD, 0);
1015 		if (err)
1016 			goto done;
1017 		err = got_reflist_insert(&new, refs, ref, cmp_cb, cmp_arg);
1018 		if (err || new == NULL /* duplicate */)
1019 			got_ref_close(ref);
1020 		if (err && err->code != GOT_ERR_NOT_REF)
1021 			goto done;
1022 	} else {
1023 		/* Try listing a single reference. */
1024 		const char *refname = ref_namespace;
1025 		path_refs = get_refs_dir_path(repo, refname);
1026 		if (path_refs == NULL) {
1027 			err = got_error_from_errno("get_refs_dir_path");
1028 			goto done;
1029 		}
1030 		err = open_ref(&ref, path_refs, "", refname, 0);
1031 		if (err) {
1032 			if (err->code != GOT_ERR_NOT_REF)
1033 				goto done;
1034 			/* Try to look up references in a given namespace. */
1035 		} else {
1036 			err = got_reflist_insert(&new, refs, ref,
1037 			    cmp_cb, cmp_arg);
1038 			if (err || new == NULL /* duplicate */)
1039 				got_ref_close(ref);
1040 			return err;
1041 		}
1042 	}
1043 
1044 	if (ref_namespace) {
1045 		size_t len;
1046 		/* Canonicalize the path to eliminate double-slashes if any. */
1047 		if (asprintf(&abs_namespace, "/%s", ref_namespace) == -1) {
1048 			err = got_error_from_errno("asprintf");
1049 			goto done;
1050 		}
1051 		len = strlen(abs_namespace) + 1;
1052 		buf = malloc(len);
1053 		if (buf == NULL) {
1054 			err = got_error_from_errno("malloc");
1055 			goto done;
1056 		}
1057 		err = got_canonpath(abs_namespace, buf, len);
1058 		if (err)
1059 			goto done;
1060 		ondisk_ref_namespace = buf;
1061 		while (ondisk_ref_namespace[0] == '/')
1062 			ondisk_ref_namespace++;
1063 		if (strncmp(ondisk_ref_namespace, "refs/", 5) == 0)
1064 			ondisk_ref_namespace += 5;
1065 		else if (strcmp(ondisk_ref_namespace, "refs") == 0)
1066 			ondisk_ref_namespace = "";
1067 	}
1068 
1069 	/* Gather on-disk refs before parsing packed-refs. */
1070 	free(path_refs);
1071 	path_refs = get_refs_dir_path(repo, "");
1072 	if (path_refs == NULL) {
1073 		err = got_error_from_errno("get_refs_dir_path");
1074 		goto done;
1075 	}
1076 	err = gather_on_disk_refs(refs, path_refs,
1077 	    ondisk_ref_namespace ? ondisk_ref_namespace : "", repo,
1078 	    cmp_cb, cmp_arg);
1079 	if (err)
1080 		goto done;
1081 
1082 	/*
1083 	 * The packed-refs file may contain redundant entries, in which
1084 	 * case on-disk refs take precedence.
1085 	 */
1086 	packed_refs_path = got_repo_get_path_packed_refs(repo);
1087 	if (packed_refs_path == NULL) {
1088 		err = got_error_from_errno("got_repo_get_path_packed_refs");
1089 		goto done;
1090 	}
1091 
1092 	f = fopen(packed_refs_path, "re");
1093 	free(packed_refs_path);
1094 	if (f) {
1095 		size_t linesize = 0;
1096 		ssize_t linelen;
1097 		struct stat sb;
1098 
1099 		if (fstat(fileno(f), &sb) == -1) {
1100 			err = got_error_from_errno2("fstat", packed_refs_path);
1101 			goto done;
1102 		}
1103 		for (;;) {
1104 			linelen = getline(&line, &linesize, f);
1105 			if (linelen == -1) {
1106 				if (feof(f))
1107 					break;
1108 				err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
1109 				goto done;
1110 			}
1111 			if (linelen > 0 && line[linelen - 1] == '\n')
1112 				line[linelen - 1] = '\0';
1113 			err = parse_packed_ref_line(&ref, NULL, line,
1114 			    sb.st_mtime);
1115 			if (err)
1116 				goto done;
1117 			if (ref) {
1118 				if (ref_namespace) {
1119 					const char *name;
1120 					name = got_ref_get_name(ref);
1121 					if (!got_path_is_child(name,
1122 					    ref_namespace,
1123 					    strlen(ref_namespace))) {
1124 						got_ref_close(ref);
1125 						continue;
1126 					}
1127 				}
1128 				err = got_reflist_insert(&new, refs, ref,
1129 				    cmp_cb, cmp_arg);
1130 				if (err || new == NULL /* duplicate */)
1131 					got_ref_close(ref);
1132 				if (err)
1133 					goto done;
1134 			}
1135 		}
1136 	}
1137 done:
1138 	free(abs_namespace);
1139 	free(buf);
1140 	free(line);
1141 	free(path_refs);
1142 	if (f && fclose(f) == EOF && err == NULL)
1143 		err = got_error_from_errno("fclose");
1144 	return err;
1145 }
1146 
1147 void
1148 got_ref_list_free(struct got_reflist_head *refs)
1149 {
1150 	struct got_reflist_entry *re;
1151 
1152 	while ((re = TAILQ_FIRST(refs))) {
1153 		TAILQ_REMOVE(refs, re, entry);
1154 		got_ref_close(re->ref);
1155 		free(re);
1156 	}
1157 
1158 }
1159 
1160 int
1161 got_ref_is_symbolic(struct got_reference *ref)
1162 {
1163 	return (ref->flags & GOT_REF_IS_SYMBOLIC);
1164 }
1165 
1166 const struct got_error *
1167 got_ref_change_ref(struct got_reference *ref, struct got_object_id *id)
1168 {
1169 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
1170 		return got_error(GOT_ERR_BAD_REF_TYPE);
1171 
1172 	memcpy(ref->ref.ref.sha1, id->sha1, sizeof(ref->ref.ref.sha1));
1173 	return NULL;
1174 }
1175 
1176 const struct got_error *
1177 got_ref_change_symref(struct got_reference *ref, const char *refname)
1178 {
1179 	char *new_name;
1180 
1181 	if ((ref->flags & GOT_REF_IS_SYMBOLIC) == 0)
1182 		return got_error(GOT_ERR_BAD_REF_TYPE);
1183 
1184 	new_name = strdup(refname);
1185 	if (new_name == NULL)
1186 		return got_error_from_errno("strdup");
1187 
1188 	free(ref->ref.symref.ref);
1189 	ref->ref.symref.ref = new_name;
1190 	return NULL;
1191 }
1192 
1193 const struct got_error *
1194 got_ref_change_symref_to_ref(struct got_reference *symref,
1195     struct got_object_id *id)
1196 {
1197 	if ((symref->flags & GOT_REF_IS_SYMBOLIC) == 0)
1198 		return got_error(GOT_ERR_BAD_REF_TYPE);
1199 
1200 	symref->ref.ref.name = symref->ref.symref.name;
1201 	memcpy(symref->ref.ref.sha1, id->sha1, SHA1_DIGEST_LENGTH);
1202 	symref->flags &= ~GOT_REF_IS_SYMBOLIC;
1203 	return NULL;
1204 }
1205 
1206 const struct got_error *
1207 got_ref_write(struct got_reference *ref, struct got_repository *repo)
1208 {
1209 	const struct got_error *err = NULL, *unlock_err = NULL;
1210 	const char *name = got_ref_get_name(ref);
1211 	char *path_refs = NULL, *path = NULL, *tmppath = NULL;
1212 	struct got_lockfile *lf = NULL;
1213 	FILE *f = NULL;
1214 	size_t n;
1215 	struct stat sb;
1216 
1217 	path_refs = get_refs_dir_path(repo, name);
1218 	if (path_refs == NULL) {
1219 		err = got_error_from_errno2("get_refs_dir_path", name);
1220 		goto done;
1221 	}
1222 
1223 	if (asprintf(&path, "%s/%s", path_refs, name) == -1) {
1224 		err = got_error_from_errno("asprintf");
1225 		goto done;
1226 	}
1227 
1228 	err = got_opentemp_named(&tmppath, &f, path);
1229 	if (err) {
1230 		char *parent;
1231 		if (!(err->code == GOT_ERR_ERRNO && errno == ENOENT))
1232 			goto done;
1233 		err = got_path_dirname(&parent, path);
1234 		if (err)
1235 			goto done;
1236 		err = got_path_mkdir(parent);
1237 		free(parent);
1238 		if (err)
1239 			goto done;
1240 		err = got_opentemp_named(&tmppath, &f, path);
1241 		if (err)
1242 			goto done;
1243 	}
1244 
1245 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
1246 		n = fprintf(f, "ref: %s\n", ref->ref.symref.ref);
1247 		if (n != strlen(ref->ref.symref.ref) + 6) {
1248 			err = got_ferror(f, GOT_ERR_IO);
1249 			goto done;
1250 		}
1251 	} else {
1252 		char hex[SHA1_DIGEST_STRING_LENGTH];
1253 		if (got_sha1_digest_to_str(ref->ref.ref.sha1, hex,
1254 		    sizeof(hex)) == NULL) {
1255 			err = got_error(GOT_ERR_BAD_REF_DATA);
1256 			goto done;
1257 		}
1258 		n = fprintf(f, "%s\n", hex);
1259 		if (n != sizeof(hex)) {
1260 			err = got_ferror(f, GOT_ERR_IO);
1261 			goto done;
1262 		}
1263 	}
1264 
1265 	if (ref->lf == NULL) {
1266 		err = got_lockfile_lock(&lf, path, -1);
1267 		if (err)
1268 			goto done;
1269 	}
1270 
1271 	/* XXX: check if old content matches our expectations? */
1272 
1273 	if (stat(path, &sb) != 0) {
1274 		if (errno != ENOENT) {
1275 			err = got_error_from_errno2("stat", path);
1276 			goto done;
1277 		}
1278 		sb.st_mode = GOT_DEFAULT_FILE_MODE;
1279 	}
1280 
1281 	if (fchmod(fileno(f), sb.st_mode) != 0) {
1282 		err = got_error_from_errno2("fchmod", tmppath);
1283 		goto done;
1284 	}
1285 
1286 	if (rename(tmppath, path) != 0) {
1287 		err = got_error_from_errno3("rename", tmppath, path);
1288 		goto done;
1289 	}
1290 	free(tmppath);
1291 	tmppath = NULL;
1292 
1293 	if (stat(path, &sb) == -1) {
1294 		err = got_error_from_errno2("stat", path);
1295 		goto done;
1296 	}
1297 	ref->mtime = sb.st_mtime;
1298 done:
1299 	if (ref->lf == NULL && lf)
1300 		unlock_err = got_lockfile_unlock(lf, -1);
1301 	if (f) {
1302 		if (fclose(f) == EOF && err == NULL)
1303 			err = got_error_from_errno("fclose");
1304 	}
1305 	free(path_refs);
1306 	free(path);
1307 	if (tmppath) {
1308 		if (unlink(tmppath) != 0 && err == NULL)
1309 			err = got_error_from_errno2("unlink", tmppath);
1310 		free(tmppath);
1311 	}
1312 	return err ? err : unlock_err;
1313 }
1314 
1315 static const struct got_error *
1316 delete_packed_ref(struct got_reference *delref, struct got_repository *repo)
1317 {
1318 	const struct got_error *err = NULL, *unlock_err = NULL;
1319 	struct got_lockfile *lf = NULL;
1320 	FILE *f = NULL, *tmpf = NULL;
1321 	char *line = NULL, *packed_refs_path, *tmppath = NULL;
1322 	size_t linesize = 0;
1323 	struct got_reflist_head refs;
1324 	int found_delref = 0;
1325 
1326 	/* The packed-refs file does not cotain symbolic references. */
1327 	if (delref->flags & GOT_REF_IS_SYMBOLIC)
1328 		return got_error(GOT_ERR_BAD_REF_DATA);
1329 
1330 	TAILQ_INIT(&refs);
1331 
1332 	packed_refs_path = got_repo_get_path_packed_refs(repo);
1333 	if (packed_refs_path == NULL)
1334 		return got_error_from_errno("got_repo_get_path_packed_refs");
1335 
1336 	err = got_opentemp_named(&tmppath, &tmpf, packed_refs_path);
1337 	if (err)
1338 		goto done;
1339 
1340 	if (delref->lf == NULL) {
1341 		err = got_lockfile_lock(&lf, packed_refs_path, -1);
1342 		if (err)
1343 			goto done;
1344 	}
1345 
1346 	f = fopen(packed_refs_path, "re");
1347 	if (f == NULL) {
1348 		err = got_error_from_errno2("fopen", packed_refs_path);
1349 		goto done;
1350 	}
1351 	for (;;) {
1352 		ssize_t linelen;
1353 		struct got_reference *ref;
1354 		struct got_reflist_entry *new;
1355 
1356 		linelen = getline(&line, &linesize, f);
1357 		if (linelen == -1) {
1358 			if (feof(f))
1359 				break;
1360 			err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
1361 			goto done;
1362 		}
1363 		if (linelen > 0 && line[linelen - 1] == '\n')
1364 			line[linelen - 1] = '\0';
1365 		err = parse_packed_ref_line(&ref, NULL, line, 0);
1366 		if (err)
1367 			goto done;
1368 		if (ref == NULL)
1369 			continue;
1370 
1371 		if (strcmp(ref->ref.ref.name, delref->ref.ref.name) == 0 &&
1372 		    memcmp(ref->ref.ref.sha1, delref->ref.ref.sha1,
1373 		    sizeof(delref->ref.ref.sha1)) == 0) {
1374 			found_delref = 1;
1375 			got_ref_close(ref);
1376 			continue;
1377 		}
1378 
1379 		err = got_reflist_insert(&new, &refs, ref,
1380 		    got_ref_cmp_by_name, NULL);
1381 		if (err || new == NULL /* duplicate */)
1382 			got_ref_close(ref);
1383 		if (err)
1384 			goto done;
1385 	}
1386 
1387 	if (found_delref) {
1388 		struct got_reflist_entry *re;
1389 		size_t n;
1390 		struct stat sb;
1391 
1392 		n = fprintf(tmpf, "%s\n", GOT_PACKED_REFS_HEADER);
1393 		if (n != sizeof(GOT_PACKED_REFS_HEADER)) {
1394 			err = got_ferror(f, GOT_ERR_IO);
1395 			goto done;
1396 		}
1397 
1398 		TAILQ_FOREACH(re, &refs, entry) {
1399 			char hex[SHA1_DIGEST_STRING_LENGTH];
1400 
1401 			if (got_sha1_digest_to_str(re->ref->ref.ref.sha1, hex,
1402 			    sizeof(hex)) == NULL) {
1403 				err = got_error(GOT_ERR_BAD_REF_DATA);
1404 				goto done;
1405 			}
1406 			n = fprintf(tmpf, "%s ", hex);
1407 			if (n != sizeof(hex)) {
1408 				err = got_ferror(f, GOT_ERR_IO);
1409 				goto done;
1410 			}
1411 			n = fprintf(tmpf, "%s\n", re->ref->ref.ref.name);
1412 			if (n != strlen(re->ref->ref.ref.name) + 1) {
1413 				err = got_ferror(f, GOT_ERR_IO);
1414 				goto done;
1415 			}
1416 		}
1417 
1418 		if (fflush(tmpf) != 0) {
1419 			err = got_error_from_errno("fflush");
1420 			goto done;
1421 		}
1422 
1423 		if (fstat(fileno(f), &sb) != 0) {
1424 			if (errno != ENOENT) {
1425 				err = got_error_from_errno2("fstat",
1426 				    packed_refs_path);
1427 				goto done;
1428 			}
1429 			sb.st_mode = GOT_DEFAULT_FILE_MODE;
1430 		}
1431 
1432 		if (fchmod(fileno(tmpf), sb.st_mode) != 0) {
1433 			err = got_error_from_errno2("fchmod", tmppath);
1434 			goto done;
1435 		}
1436 
1437 		if (rename(tmppath, packed_refs_path) != 0) {
1438 			err = got_error_from_errno3("rename", tmppath,
1439 			    packed_refs_path);
1440 			goto done;
1441 		}
1442 	}
1443 done:
1444 	if (delref->lf == NULL && lf)
1445 		unlock_err = got_lockfile_unlock(lf, -1);
1446 	if (f) {
1447 		if (fclose(f) == EOF && err == NULL)
1448 			err = got_error_from_errno("fclose");
1449 	}
1450 	if (tmpf) {
1451 		unlink(tmppath);
1452 		if (fclose(tmpf) == EOF && err == NULL)
1453 			err = got_error_from_errno("fclose");
1454 	}
1455 	free(tmppath);
1456 	free(packed_refs_path);
1457 	free(line);
1458 	got_ref_list_free(&refs);
1459 	return err ? err : unlock_err;
1460 }
1461 
1462 static const struct got_error *
1463 delete_loose_ref(struct got_reference *ref, struct got_repository *repo)
1464 {
1465 	const struct got_error *err = NULL, *unlock_err = NULL;
1466 	const char *name = got_ref_get_name(ref);
1467 	char *path_refs = NULL, *path = NULL;
1468 	struct got_lockfile *lf = NULL;
1469 
1470 	path_refs = get_refs_dir_path(repo, name);
1471 	if (path_refs == NULL) {
1472 		err = got_error_from_errno2("get_refs_dir_path", name);
1473 		goto done;
1474 	}
1475 
1476 	if (asprintf(&path, "%s/%s", path_refs, name) == -1) {
1477 		err = got_error_from_errno("asprintf");
1478 		goto done;
1479 	}
1480 
1481 	if (ref->lf == NULL) {
1482 		err = got_lockfile_lock(&lf, path, -1);
1483 		if (err)
1484 			goto done;
1485 	}
1486 
1487 	/* XXX: check if old content matches our expectations? */
1488 
1489 	if (unlink(path) != 0)
1490 		err = got_error_from_errno2("unlink", path);
1491 done:
1492 	if (ref->lf == NULL && lf)
1493 		unlock_err = got_lockfile_unlock(lf, -1);
1494 
1495 	free(path_refs);
1496 	free(path);
1497 	return err ? err : unlock_err;
1498 }
1499 
1500 const struct got_error *
1501 got_ref_delete(struct got_reference *ref, struct got_repository *repo)
1502 {
1503 	const struct got_error *err = NULL;
1504 	struct got_reference *ref2;
1505 
1506 	if (ref->flags & GOT_REF_IS_PACKED) {
1507 		err = delete_packed_ref(ref, repo);
1508 		if (err)
1509 			return err;
1510 
1511 		err = got_ref_open(&ref2, repo, got_ref_get_name(ref), 0);
1512 		if (err) {
1513 			if (err->code == GOT_ERR_NOT_REF)
1514 				return NULL;
1515 			return err;
1516 		}
1517 
1518 		err = delete_loose_ref(ref2, repo);
1519 		got_ref_close(ref2);
1520 		return err;
1521 	} else {
1522 		err = delete_loose_ref(ref, repo);
1523 		if (err)
1524 			return err;
1525 
1526 		err = got_ref_open(&ref2, repo, got_ref_get_name(ref), 0);
1527 		if (err) {
1528 			if (err->code == GOT_ERR_NOT_REF)
1529 				return NULL;
1530 			return err;
1531 		}
1532 
1533 		err = delete_packed_ref(ref2, repo);
1534 		got_ref_close(ref2);
1535 		return err;
1536 	}
1537 }
1538 
1539 const struct got_error *
1540 got_ref_unlock(struct got_reference *ref)
1541 {
1542 	const struct got_error *err;
1543 	err = got_lockfile_unlock(ref->lf, -1);
1544 	ref->lf = NULL;
1545 	return err;
1546 }
1547 
1548 struct got_reflist_object_id_map {
1549 	struct got_object_idset *idset;
1550 };
1551 
1552 struct got_reflist_object_id_map_entry {
1553 	struct got_reflist_head refs;
1554 };
1555 
1556 static const struct got_error *
1557 add_object_id_map_entry(struct got_object_idset *idset,
1558     struct got_object_id *id, struct got_reflist_entry *re)
1559 {
1560 	const struct got_error *err = NULL;
1561 	struct got_reflist_object_id_map_entry *ent;
1562 	struct got_reflist_entry *new;
1563 
1564 	ent = got_object_idset_get(idset, id);
1565 	if (ent == NULL) {
1566 		ent = malloc(sizeof(*ent));
1567 		if (ent == NULL)
1568 			return got_error_from_errno("malloc");
1569 
1570 		TAILQ_INIT(&ent->refs);
1571 		err = got_object_idset_add(idset, id, ent);
1572 		if (err) {
1573 			free(ent);
1574 			return err;
1575 		}
1576 	}
1577 
1578 	err = got_reflist_entry_dup(&new, re);
1579 	if (err)
1580 		return err;
1581 
1582 	TAILQ_INSERT_TAIL(&ent->refs, new, entry);
1583 	return NULL;
1584 }
1585 
1586 const struct got_error *
1587 got_reflist_object_id_map_create(struct got_reflist_object_id_map **map,
1588     struct got_reflist_head *refs, struct got_repository *repo)
1589 {
1590 	const struct got_error *err = NULL;
1591 	struct got_object_idset *idset;
1592 	struct got_object_id *id = NULL;
1593 	struct got_reflist_entry *re;
1594 
1595 	idset = got_object_idset_alloc();
1596 	if (idset == NULL)
1597 		return got_error_from_errno("got_object_idset_alloc");
1598 
1599 	*map = malloc(sizeof(**map));
1600 	if (*map == NULL) {
1601 		got_object_idset_free(idset);
1602 		return got_error_from_errno("malloc");
1603 	}
1604 	(*map)->idset = idset;
1605 
1606 	TAILQ_FOREACH(re, refs, entry) {
1607 		struct got_tag_object *tag = NULL;
1608 
1609 		err = got_ref_resolve(&id, repo, re->ref);
1610 		if (err)
1611 			goto done;
1612 
1613 		err = add_object_id_map_entry(idset, id, re);
1614 		if (err)
1615 			goto done;
1616 
1617 		if (strstr(got_ref_get_name(re->ref), "/tags/") == NULL) {
1618 			free(id);
1619 			id = NULL;
1620 			continue;
1621 		}
1622 
1623 		err = got_object_open_as_tag(&tag, repo, id);
1624 		if (err) {
1625 			if (err->code != GOT_ERR_OBJ_TYPE)
1626 				goto done;
1627 			/* Ref points at something other than a tag. */
1628 			err = NULL;
1629 			tag = NULL;
1630 			free(id);
1631 			id = NULL;
1632 			continue;
1633 		}
1634 
1635 		err = add_object_id_map_entry(idset,
1636 		    got_object_tag_get_object_id(tag), re);
1637 		got_object_tag_close(tag);
1638 		if (err)
1639 			goto done;
1640 
1641 		free(id);
1642 		id = NULL;
1643 	}
1644 done:
1645 	free(id);
1646 	if (err) {
1647 		got_reflist_object_id_map_free(*map);
1648 		*map = NULL;
1649 	}
1650 	return err;
1651 }
1652 
1653 struct got_reflist_head *
1654 got_reflist_object_id_map_lookup(struct got_reflist_object_id_map *map,
1655     struct got_object_id *id)
1656 {
1657 	struct got_reflist_object_id_map_entry *ent;
1658 	ent = got_object_idset_get(map->idset, id);
1659 	if (ent)
1660 		return &ent->refs;
1661 	return NULL;
1662 }
1663 
1664 static const struct got_error *
1665 free_id_map_entry(struct got_object_id *id, void *data, void *arg)
1666 {
1667 	struct got_reflist_object_id_map_entry *ent = data;
1668 
1669 	got_ref_list_free(&ent->refs);
1670 	free(ent);
1671 	return NULL;
1672 }
1673 
1674 void
1675 got_reflist_object_id_map_free(struct got_reflist_object_id_map *map)
1676 {
1677 	got_object_idset_for_each(map->idset, free_id_map_entry, NULL);
1678 	got_object_idset_free(map->idset);
1679 	free(map);
1680 }