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Date:: Tue Jul 27 13:08:51 2021 UTC
Message:: track the last modification time of references
Actions:: History | Blame | Raw File
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 
93 static const struct got_error *
94 alloc_ref(struct got_reference **ref, const char *name,
95     struct got_object_id *id, int flags, time_t mtime)
96 {
97 	const struct got_error *err = NULL;
98 
99 	*ref = calloc(1, sizeof(**ref));
100 	if (*ref == NULL)
101 		return got_error_from_errno("calloc");
102 
103 	memcpy((*ref)->ref.ref.sha1, id->sha1, sizeof((*ref)->ref.ref.sha1));
104 	(*ref)->flags = flags;
105 	(*ref)->ref.ref.name = strdup(name);
106 	(*ref)->mtime = mtime;
107 	if ((*ref)->ref.ref.name == NULL) {
108 		err = got_error_from_errno("strdup");
109 		got_ref_close(*ref);
110 		*ref = NULL;
111 	}
112 	return err;
113 }
114 
115 static const struct got_error *
116 alloc_symref(struct got_reference **ref, const char *name,
117     const char *target_ref, int flags)
118 {
119 	const struct got_error *err = NULL;
120 
121 	*ref = calloc(1, sizeof(**ref));
122 	if (*ref == NULL)
123 		return got_error_from_errno("calloc");
124 
125 	(*ref)->flags = GOT_REF_IS_SYMBOLIC | flags;
126 	(*ref)->ref.symref.name = strdup(name);
127 	if ((*ref)->ref.symref.name == NULL) {
128 		err = got_error_from_errno("strdup");
129 		got_ref_close(*ref);
130 		*ref = NULL;
131 		return err;
132 	}
133 	(*ref)->ref.symref.ref = strdup(target_ref);
134 	if ((*ref)->ref.symref.ref == NULL) {
135 		err = got_error_from_errno("strdup");
136 		got_ref_close(*ref);
137 		*ref = NULL;
138 	}
139 	return err;
140 }
141 
142 static const struct got_error *
143 parse_symref(struct got_reference **ref, const char *name, const char *line)
144 {
145 	if (line[0] == '\0')
146 		return got_error(GOT_ERR_BAD_REF_DATA);
147 
148 	return alloc_symref(ref, name, line, 0);
149 }
150 
151 static const struct got_error *
152 parse_ref_line(struct got_reference **ref, const char *name, const char *line,
153     time_t mtime)
154 {
155 	struct got_object_id id;
156 
157 	if (strncmp(line, "ref: ", 5) == 0) {
158 		line += 5;
159 		return parse_symref(ref, name, line);
160 	}
161 
162 	if (!got_parse_sha1_digest(id.sha1, line))
163 		return got_error(GOT_ERR_BAD_REF_DATA);
164 
165 	return alloc_ref(ref, name, &id, 0, mtime);
166 }
167 
168 static const struct got_error *
169 parse_ref_file(struct got_reference **ref, const char *name,
170     const char *absname, const char *abspath, int lock)
171 {
172 	const struct got_error *err = NULL;
173 	FILE *f;
174 	char *line = NULL;
175 	size_t linesize = 0;
176 	ssize_t linelen;
177 	struct got_lockfile *lf = NULL;
178 	struct stat sb;
179 
180 	if (lock) {
181 		err = got_lockfile_lock(&lf, abspath, -1);
182 		if (err) {
183 			if (err->code == GOT_ERR_ERRNO && errno == ENOENT)
184 				err = got_error_not_ref(name);
185 			return err;
186 		}
187 	}
188 
189 	f = fopen(abspath, "rb");
190 	if (f == NULL) {
191 		if (errno != ENOTDIR && errno != ENOENT)
192 			err = got_error_from_errno2("fopen", abspath);
193 		else
194 			err = got_error_not_ref(name);
195 		if (lock)
196 			got_lockfile_unlock(lf, -1);
197 		return err;
198 	}
199 	if (fstat(fileno(f), &sb) == -1) {
200 		err = got_error_from_errno2("fstat", abspath);
201 		goto done;
202 	}
203 
204 	linelen = getline(&line, &linesize, f);
205 	if (linelen == -1) {
206 		if (feof(f))
207 			err = NULL; /* ignore empty files (could be locks) */
208 		else {
209 			if (errno == EISDIR)
210 				err = got_error(GOT_ERR_NOT_REF);
211 			else if (ferror(f))
212 				err = got_ferror(f, GOT_ERR_IO);
213 			else
214 				err = got_error_from_errno2("getline", abspath);
215 		}
216 		if (lock)
217 			got_lockfile_unlock(lf, -1);
218 		goto done;
219 	}
220 	while (linelen > 0 && line[linelen - 1] == '\n') {
221 		line[linelen - 1] = '\0';
222 		linelen--;
223 	}
224 
225 	err = parse_ref_line(ref, absname, line, sb.st_mtime);
226 	if (lock) {
227 		if (err)
228 			got_lockfile_unlock(lf, -1);
229 		else {
230 			if (*ref)
231 				(*ref)->lf = lf;
232 			else
233 				got_lockfile_unlock(lf, -1);
234 		}
235 	}
236 done:
237 	free(line);
238 	if (fclose(f) == EOF && err == NULL) {
239 		err = got_error_from_errno("fclose");
240 		if (*ref) {
241 			if (lock)
242 				got_ref_unlock(*ref);
243 			got_ref_close(*ref);
244 			*ref = NULL;
245 		}
246 	}
247 	return err;
248 }
249 
250 static int
251 is_well_known_ref(const char *refname)
252 {
253 	return (strcmp(refname, GOT_REF_HEAD) == 0 ||
254 	    strcmp(refname, GOT_REF_ORIG_HEAD) == 0 ||
255 	    strcmp(refname, GOT_REF_MERGE_HEAD) == 0 ||
256 	    strcmp(refname, GOT_REF_FETCH_HEAD) == 0);
257 }
258 
259 static char *
260 get_refs_dir_path(struct got_repository *repo, const char *refname)
261 {
262 	if (is_well_known_ref(refname) || strncmp(refname, "refs/", 5) == 0)
263 		return strdup(got_repo_get_path_git_dir(repo));
264 
265 	return got_repo_get_path_refs(repo);
266 }
267 
268 static int
269 is_valid_ref_name(const char *name)
270 {
271 	const char *s, *seg;
272 	const char forbidden[] = { ' ', '~', '^', ':', '?', '*', '[' , '\\' };
273 	const char *forbidden_seq[] = { "//", "..", "@{" };
274 	const char *lfs = GOT_LOCKFILE_SUFFIX;
275 	const size_t lfs_len = sizeof(GOT_LOCKFILE_SUFFIX) - 1;
276 	size_t i;
277 
278 	if (name[0] == '@' && name[1] == '\0')
279 		return 0;
280 
281 	s = name;
282 	seg = s;
283 	if (seg[0] == '\0' || seg[0] == '.' || seg[0] == '/')
284 		return 0;
285 	while (*s) {
286 		for (i = 0; i < nitems(forbidden); i++) {
287 			if (*s == forbidden[i])
288 				return 0;
289 		}
290 		for (i = 0; i < nitems(forbidden_seq); i++) {
291 			if (s[0] == forbidden_seq[i][0] &&
292 			    s[1] == forbidden_seq[i][1])
293 				return 0;
294 		}
295 		if (iscntrl((unsigned char)s[0]))
296 			return 0;
297 		if (s[0] == '.' && s[1] == '\0')
298 			return 0;
299 		if (*s == '/') {
300 			const char *nextseg = s + 1;
301 			if (nextseg[0] == '\0' || nextseg[0] == '.' ||
302 			    nextseg[0] == '/')
303 				return 0;
304 			if (seg <= s - lfs_len &&
305 			    strncmp(s - lfs_len, lfs, lfs_len) == 0)
306 				return 0;
307 			seg = nextseg;
308 		}
309 		s++;
310 	}
311 
312 	if (seg <= s - lfs_len &&
313 	    strncmp(s - lfs_len, lfs, lfs_len) == 0)
314 		return 0;
315 
316 	return 1;
317 }
318 
319 const struct got_error *
320 got_ref_alloc(struct got_reference **ref, const char *name,
321     struct got_object_id *id)
322 {
323 	if (!is_valid_ref_name(name))
324 		return got_error_path(name, GOT_ERR_BAD_REF_NAME);
325 
326 	return alloc_ref(ref, name, id, 0, 0);
327 }
328 
329 const struct got_error *
330 got_ref_alloc_symref(struct got_reference **ref, const char *name,
331 	struct got_reference *target_ref)
332 {
333 	if (!is_valid_ref_name(name))
334 		return got_error_path(name, GOT_ERR_BAD_REF_NAME);
335 
336 	return alloc_symref(ref, name, got_ref_get_name(target_ref), 0);
337 }
338 
339 static const struct got_error *
340 parse_packed_ref_line(struct got_reference **ref, const char *abs_refname,
341     const char *line, time_t mtime)
342 {
343 	struct got_object_id id;
344 	const char *name;
345 
346 	*ref = NULL;
347 
348 	if (line[0] == '#' || line[0] == '^')
349 		return NULL;
350 
351 	if (!got_parse_sha1_digest(id.sha1, line))
352 		return got_error(GOT_ERR_BAD_REF_DATA);
353 
354 	if (abs_refname) {
355 		if (strcmp(line + SHA1_DIGEST_STRING_LENGTH, abs_refname) != 0)
356 			return NULL;
357 		name = abs_refname;
358 	} else
359 		name = line + SHA1_DIGEST_STRING_LENGTH;
360 
361 	return alloc_ref(ref, name, &id, GOT_REF_IS_PACKED, mtime);
362 }
363 
364 static const struct got_error *
365 open_packed_ref(struct got_reference **ref, FILE *f, const char **subdirs,
366     int nsubdirs, const char *refname, time_t mtime)
367 {
368 	const struct got_error *err = NULL;
369 	char *abs_refname;
370 	char *line = NULL;
371 	size_t linesize = 0;
372 	ssize_t linelen;
373 	int i, ref_is_absolute = (strncmp(refname, "refs/", 5) == 0);
374 
375 	*ref = NULL;
376 
377 	if (ref_is_absolute)
378 		abs_refname = (char *)refname;
379 	do {
380 		linelen = getline(&line, &linesize, f);
381 		if (linelen == -1) {
382 			if (feof(f))
383 				break;
384 			err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
385 			break;
386 		}
387 		if (linelen > 0 && line[linelen - 1] == '\n')
388 			line[linelen - 1] = '\0';
389 		for (i = 0; i < nsubdirs; i++) {
390 			if (!ref_is_absolute &&
391 			    asprintf(&abs_refname, "refs/%s/%s", subdirs[i],
392 			    refname) == -1)
393 				return got_error_from_errno("asprintf");
394 			err = parse_packed_ref_line(ref, abs_refname, line,
395 			    mtime);
396 			if (!ref_is_absolute)
397 				free(abs_refname);
398 			if (err || *ref != NULL)
399 				break;
400 		}
401 		if (err)
402 			break;
403 	} while (*ref == NULL);
404 	free(line);
405 
406 	return err;
407 }
408 
409 static const struct got_error *
410 open_ref(struct got_reference **ref, const char *path_refs, const char *subdir,
411     const char *name, int lock)
412 {
413 	const struct got_error *err = NULL;
414 	char *path = NULL;
415 	char *absname = NULL;
416 	int ref_is_absolute = (strncmp(name, "refs/", 5) == 0);
417 	int ref_is_well_known = (subdir[0] == '\0' && is_well_known_ref(name));
418 
419 	*ref = NULL;
420 
421 	if (!is_valid_ref_name(name))
422 		return got_error_path(name, GOT_ERR_BAD_REF_NAME);
423 
424 	if (ref_is_absolute || ref_is_well_known) {
425 		if (asprintf(&path, "%s/%s", path_refs, name) == -1)
426 			return got_error_from_errno("asprintf");
427 		absname = (char *)name;
428 	} else {
429 		if (asprintf(&path, "%s/%s%s%s", path_refs, subdir,
430 		    subdir[0] ? "/" : "", name) == -1)
431 			return got_error_from_errno("asprintf");
432 
433 		if (asprintf(&absname, "refs/%s%s%s",
434 		    subdir, subdir[0] ? "/" : "", name) == -1) {
435 			err = got_error_from_errno("asprintf");
436 			goto done;
437 		}
438 	}
439 
440 	err = parse_ref_file(ref, name, absname, path, lock);
441 done:
442 	if (!ref_is_absolute && !ref_is_well_known)
443 		free(absname);
444 	free(path);
445 	return err;
446 }
447 
448 const struct got_error *
449 got_ref_open(struct got_reference **ref, struct got_repository *repo,
450    const char *refname, int lock)
451 {
452 	const struct got_error *err = NULL;
453 	char *path_refs = NULL;
454 	const char *subdirs[] = {
455 	    GOT_REF_HEADS, GOT_REF_TAGS, GOT_REF_REMOTES
456 	};
457 	size_t i;
458 	int well_known = is_well_known_ref(refname);
459 	struct got_lockfile *lf = NULL;
460 
461 	*ref = NULL;
462 
463 	path_refs = get_refs_dir_path(repo, refname);
464 	if (path_refs == NULL) {
465 		err = got_error_from_errno2("get_refs_dir_path", refname);
466 		goto done;
467 	}
468 
469 	if (well_known) {
470 		err = open_ref(ref, path_refs, "", refname, lock);
471 	} else {
472 		char *packed_refs_path;
473 		FILE *f;
474 
475 		/* Search on-disk refs before packed refs! */
476 		for (i = 0; i < nitems(subdirs); i++) {
477 			err = open_ref(ref, path_refs, subdirs[i], refname,
478 			    lock);
479 			if ((err && err->code != GOT_ERR_NOT_REF) || *ref)
480 				goto done;
481 		}
482 
483 		packed_refs_path = got_repo_get_path_packed_refs(repo);
484 		if (packed_refs_path == NULL) {
485 			err = got_error_from_errno(
486 			    "got_repo_get_path_packed_refs");
487 			goto done;
488 		}
489 
490 		if (lock) {
491 			err = got_lockfile_lock(&lf, packed_refs_path, -1);
492 			if (err)
493 				goto done;
494 		}
495 		f = fopen(packed_refs_path, "rb");
496 		free(packed_refs_path);
497 		if (f != NULL) {
498 			struct stat sb;
499 			if (fstat(fileno(f), &sb) == -1) {
500 				err = got_error_from_errno2("fstat",
501 				    packed_refs_path);
502 				goto done;
503 			}
504 			err = open_packed_ref(ref, f, subdirs, nitems(subdirs),
505 			    refname, sb.st_mtime);
506 			if (!err) {
507 				if (fclose(f) == EOF) {
508 					err = got_error_from_errno("fclose");
509 					got_ref_close(*ref);
510 					*ref = NULL;
511 				} else if (*ref)
512 					(*ref)->lf = lf;
513 			}
514 		}
515 	}
516 done:
517 	if (!err && *ref == NULL)
518 		err = got_error_not_ref(refname);
519 	if (err && lf)
520 		got_lockfile_unlock(lf, -1);
521 	free(path_refs);
522 	return err;
523 }
524 
525 void
526 got_ref_close(struct got_reference *ref)
527 {
528 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
529 		free(ref->ref.symref.name);
530 		free(ref->ref.symref.ref);
531 	} else
532 		free(ref->ref.ref.name);
533 	free(ref);
534 }
535 
536 struct got_reference *
537 got_ref_dup(struct got_reference *ref)
538 {
539 	struct got_reference *ret;
540 
541 	ret = calloc(1, sizeof(*ret));
542 	if (ret == NULL)
543 		return NULL;
544 
545 	ret->flags = ref->flags;
546 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
547 		ret->ref.symref.name = strdup(ref->ref.symref.name);
548 		if (ret->ref.symref.name == NULL) {
549 			free(ret);
550 			return NULL;
551 		}
552 		ret->ref.symref.ref = strdup(ref->ref.symref.ref);
553 		if (ret->ref.symref.ref == NULL) {
554 			free(ret->ref.symref.name);
555 			free(ret);
556 			return NULL;
557 		}
558 	} else {
559 		ret->ref.ref.name = strdup(ref->ref.ref.name);
560 		if (ret->ref.ref.name == NULL) {
561 			free(ret);
562 			return NULL;
563 		}
564 		memcpy(ret->ref.ref.sha1, ref->ref.ref.sha1,
565 		    sizeof(ret->ref.ref.sha1));
566 	}
567 
568 	return ret;
569 }
570 
571 const struct got_error *
572 got_reflist_entry_dup(struct got_reflist_entry **newp,
573     struct got_reflist_entry *re)
574 {
575 	const struct got_error *err = NULL;
576 	struct got_reflist_entry *new;
577 
578 	*newp = NULL;
579 
580 	new = malloc(sizeof(*new));
581 	if (new == NULL)
582 		return got_error_from_errno("malloc");
583 
584 	new->ref = got_ref_dup(re->ref);
585 	if (new->ref == NULL) {
586 		err = got_error_from_errno("got_ref_dup");
587 		free(new);
588 		return err;
589 	}
590 
591 	*newp = new;
592 	return NULL;
593 }
594 
595 static const struct got_error *
596 resolve_symbolic_ref(struct got_reference **resolved,
597     struct got_repository *repo, struct got_reference *ref)
598 {
599 	struct got_reference *nextref;
600 	const struct got_error *err;
601 
602 	err = got_ref_open(&nextref, repo, ref->ref.symref.ref, 0);
603 	if (err)
604 		return err;
605 
606 	if (nextref->flags & GOT_REF_IS_SYMBOLIC)
607 		err = resolve_symbolic_ref(resolved, repo, nextref);
608 	else
609 		*resolved = got_ref_dup(nextref);
610 
611 	got_ref_close(nextref);
612 	return err;
613 }
614 
615 static const struct got_error *
616 ref_resolve(struct got_object_id **id, struct got_repository *repo,
617     struct got_reference *ref, int recursion)
618 {
619 	const struct got_error *err;
620 
621 	if (recursion <= 0)
622 		return got_error_msg(GOT_ERR_RECURSION,
623 		    "reference recursion limit reached");
624 
625 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
626 		struct got_reference *resolved = NULL;
627 		err = resolve_symbolic_ref(&resolved, repo, ref);
628 		if (err == NULL)
629 			err = ref_resolve(id, repo, resolved, --recursion);
630 		if (resolved)
631 			got_ref_close(resolved);
632 		return err;
633 	}
634 
635 	*id = calloc(1, sizeof(**id));
636 	if (*id == NULL)
637 		return got_error_from_errno("calloc");
638 	memcpy((*id)->sha1, ref->ref.ref.sha1, sizeof((*id)->sha1));
639 	return NULL;
640 }
641 
642 const struct got_error *
643 got_ref_resolve(struct got_object_id **id, struct got_repository *repo,
644     struct got_reference *ref)
645 {
646 	return ref_resolve(id, repo, ref, GOT_REF_RECURSE_MAX);
647 }
648 
649 char *
650 got_ref_to_str(struct got_reference *ref)
651 {
652 	char *str;
653 
654 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
655 		return strdup(ref->ref.symref.ref);
656 
657 	str = malloc(SHA1_DIGEST_STRING_LENGTH);
658 	if (str == NULL)
659 		return NULL;
660 
661 	if (got_sha1_digest_to_str(ref->ref.ref.sha1, str,
662 	    SHA1_DIGEST_STRING_LENGTH) == NULL) {
663 		free(str);
664 		return NULL;
665 	}
666 
667 	return str;
668 }
669 
670 const char *
671 got_ref_get_name(struct got_reference *ref)
672 {
673 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
674 		return ref->ref.symref.name;
675 
676 	return ref->ref.ref.name;
677 }
678 
679 const char *
680 got_ref_get_symref_target(struct got_reference *ref)
681 {
682 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
683 		return ref->ref.symref.ref;
684 
685 	return NULL;
686 }
687 
688 time_t
689 got_ref_get_mtime(struct got_reference *ref)
690 {
691 	return ref->mtime;
692 }
693 
694 const struct got_error *
695 got_ref_cmp_by_name(void *arg, int *cmp, struct got_reference *re1,
696     struct got_reference* re2)
697 {
698 	const char *name1 = got_ref_get_name(re1);
699 	const char *name2 = got_ref_get_name(re2);
700 
701 	*cmp = got_path_cmp(name1, name2, strlen(name1), strlen(name2));
702 	return NULL;
703 }
704 
705 const struct got_error *
706 got_ref_cmp_tags(void *arg, int *cmp, struct got_reference *ref1,
707     struct got_reference *ref2)
708 {
709 	const struct got_error *err = NULL;
710 	struct got_repository *repo = arg;
711 	struct got_object_id *id1, *id2 = NULL;
712 	struct got_tag_object *tag1 = NULL, *tag2 = NULL;
713 	struct got_commit_object *commit1 = NULL, *commit2 = NULL;
714 	time_t time1, time2;
715 
716 	*cmp = 0;
717 
718 	err = got_ref_resolve(&id1, repo, ref1);
719 	if (err)
720 		return err;
721 	err = got_object_open_as_tag(&tag1, repo, id1);
722 	if (err) {
723 		if (err->code != GOT_ERR_OBJ_TYPE)
724 			goto done;
725 		/* "lightweight" tag */
726 		err = got_object_open_as_commit(&commit1, repo, id1);
727 		if (err)
728 			goto done;
729 		time1 = got_object_commit_get_committer_time(commit1);
730 	} else
731 		time1 = got_object_tag_get_tagger_time(tag1);
732 
733 	err = got_ref_resolve(&id2, repo, ref2);
734 	if (err)
735 		goto done;
736 	err = got_object_open_as_tag(&tag2, repo, id2);
737 	if (err) {
738 		if (err->code != GOT_ERR_OBJ_TYPE)
739 			goto done;
740 		/* "lightweight" tag */
741 		err = got_object_open_as_commit(&commit2, repo, id2);
742 		if (err)
743 			goto done;
744 		time2 = got_object_commit_get_committer_time(commit2);
745 	} else
746 		time2 = got_object_tag_get_tagger_time(tag2);
747 
748 	/* Put latest tags first. */
749 	if (time1 < time2)
750 		*cmp = 1;
751 	else if (time1 > time2)
752 		*cmp = -1;
753 	else
754 		err = got_ref_cmp_by_name(NULL, cmp, ref2, ref1);
755 done:
756 	free(id1);
757 	free(id2);
758 	if (tag1)
759 		got_object_tag_close(tag1);
760 	if (tag2)
761 		got_object_tag_close(tag2);
762 	if (commit1)
763 		got_object_commit_close(commit1);
764 	if (commit2)
765 		got_object_commit_close(commit2);
766 	return err;
767 }
768 
769 const struct got_error *
770 got_ref_cmp_by_commit_timestamp_descending(void *arg, int *cmp,
771     struct got_reference *ref1, struct got_reference *ref2)
772 {
773 	const struct got_error *err;
774 	struct got_repository *repo = arg;
775 	struct got_object_id *id1, *id2 = NULL;
776 	struct got_commit_object *commit1 = NULL, *commit2 = NULL;
777 	time_t time1, time2;
778 
779 	*cmp = 0;
780 
781 	err = got_ref_resolve(&id1, repo, ref1);
782 	if (err)
783 		return err;
784 	err = got_ref_resolve(&id2, repo, ref2);
785 	if (err)
786 		goto done;
787 
788 	err = got_object_open_as_commit(&commit1, repo, id1);
789 	if (err)
790 		goto done;
791 	err = got_object_open_as_commit(&commit2, repo, id2);
792 	if (err)
793 		goto done;
794 	
795 	time1 = got_object_commit_get_committer_time(commit1);
796 	time2 = got_object_commit_get_committer_time(commit2);
797 	if (time1 < time2)
798 		*cmp = 1;
799 	else if (time2 < time1)
800 		*cmp = -1;
801 done:
802 	free(id1);
803 	free(id2);
804 	if (commit1)
805 		got_object_commit_close(commit1);
806 	if (commit2)
807 		got_object_commit_close(commit2);
808 	return err;
809 }
810 
811 const struct got_error *
812 got_reflist_insert(struct got_reflist_entry **newp, struct got_reflist_head *refs,
813     struct got_reference *ref, struct got_repository *repo,
814     got_ref_cmp_cb cmp_cb, void *cmp_arg)
815 {
816 	const struct got_error *err;
817 	struct got_reflist_entry *new, *re;
818 	int cmp;
819 
820 	*newp = NULL;
821 
822 	new = malloc(sizeof(*new));
823 	if (new == NULL)
824 		return got_error_from_errno("malloc");
825 	new->ref = ref;
826 	*newp = new;
827 
828 	/*
829 	 * We must de-duplicate entries on insert because packed-refs may
830 	 * contain redundant entries. On-disk refs take precedence.
831 	 * This code assumes that on-disk revs are read before packed-refs.
832 	 * We're iterating the list anyway, so insert elements sorted by name.
833 	 *
834 	 * Many callers will provide paths in a somewhat sorted order.
835 	 * Iterating backwards from the tail of the list should be more
836 	 * efficient than traversing through the entire list each time
837 	 * an element is inserted.
838 	 */
839 	re = TAILQ_LAST(refs, got_reflist_head);
840 	while (re) {
841 		err = (*cmp_cb)(cmp_arg, &cmp, re->ref, new->ref);
842 		if (err)
843 			return err;
844 		if (cmp == 0) {
845 			/* duplicate */
846 			free(new);
847 			*newp = NULL;
848 			return NULL;
849 		} else if (cmp < 0) {
850 			TAILQ_INSERT_AFTER(refs, re, new, entry);
851 			return NULL;
852 		}
853 		re = TAILQ_PREV(re, got_reflist_head, entry);
854 	}
855 
856 	TAILQ_INSERT_HEAD(refs, new, entry);
857 	return NULL;
858 }
859 
860 static const struct got_error *
861 gather_on_disk_refs(struct got_reflist_head *refs, const char *path_refs,
862     const char *subdir, struct got_repository *repo,
863     got_ref_cmp_cb cmp_cb, void *cmp_arg)
864 {
865 	const struct got_error *err = NULL;
866 	DIR *d = NULL;
867 	char *path_subdir;
868 
869 	while (subdir[0] == '/')
870 		subdir++;
871 
872 	if (asprintf(&path_subdir, "%s/%s", path_refs, subdir) == -1)
873 		return got_error_from_errno("asprintf");
874 
875 	d = opendir(path_subdir);
876 	if (d == NULL)
877 		goto done;
878 
879 	for (;;) {
880 		struct dirent *dent;
881 		struct got_reference *ref;
882 		char *child;
883 		int type;
884 
885 		dent = readdir(d);
886 		if (dent == NULL)
887 			break;
888 
889 		if (strcmp(dent->d_name, ".") == 0 ||
890 		    strcmp(dent->d_name, "..") == 0)
891 			continue;
892 
893 		err = got_path_dirent_type(&type, path_subdir, dent);
894 		if (err)
895 			break;
896 
897 		switch (type) {
898 		case DT_REG:
899 			err = open_ref(&ref, path_refs, subdir, dent->d_name,
900 			    0);
901 			if (err)
902 				goto done;
903 			if (ref) {
904 				struct got_reflist_entry *new;
905 				err = got_reflist_insert(&new, refs, ref, repo,
906 				    cmp_cb, cmp_arg);
907 				if (err || new == NULL /* duplicate */)
908 					got_ref_close(ref);
909 				if (err)
910 					goto done;
911 			}
912 			break;
913 		case DT_DIR:
914 			if (asprintf(&child, "%s%s%s", subdir,
915 			    subdir[0] == '\0' ? "" : "/", dent->d_name) == -1) {
916 				err = got_error_from_errno("asprintf");
917 				break;
918 			}
919 			err = gather_on_disk_refs(refs, path_refs, child, repo,
920 			    cmp_cb, cmp_arg);
921 			free(child);
922 			break;
923 		default:
924 			break;
925 		}
926 	}
927 done:
928 	if (d)
929 		closedir(d);
930 	free(path_subdir);
931 	return err;
932 }
933 
934 const struct got_error *
935 got_ref_list(struct got_reflist_head *refs, struct got_repository *repo,
936     const char *ref_namespace, got_ref_cmp_cb cmp_cb, void *cmp_arg)
937 {
938 	const struct got_error *err;
939 	char *packed_refs_path, *path_refs = NULL;
940 	char *abs_namespace = NULL;
941 	char *buf = NULL, *ondisk_ref_namespace = NULL;
942 	char *line = NULL;
943 	FILE *f = NULL;
944 	struct got_reference *ref;
945 	struct got_reflist_entry *new;
946 
947 	if (ref_namespace == NULL || ref_namespace[0] == '\0') {
948 		path_refs = get_refs_dir_path(repo, GOT_REF_HEAD);
949 		if (path_refs == NULL) {
950 			err = got_error_from_errno("get_refs_dir_path");
951 			goto done;
952 		}
953 		err = open_ref(&ref, path_refs, "", GOT_REF_HEAD, 0);
954 		if (err)
955 			goto done;
956 		err = got_reflist_insert(&new, refs, ref, repo,
957 		    cmp_cb, cmp_arg);
958 		if (err || new == NULL /* duplicate */)
959 			got_ref_close(ref);
960 		if (err && err->code != GOT_ERR_NOT_REF)
961 			goto done;
962 	} else {
963 		/* Try listing a single reference. */
964 		const char *refname = ref_namespace;
965 		path_refs = get_refs_dir_path(repo, refname);
966 		if (path_refs == NULL) {
967 			err = got_error_from_errno("get_refs_dir_path");
968 			goto done;
969 		}
970 		err = open_ref(&ref, path_refs, "", refname, 0);
971 		if (err) {
972 			if (err->code != GOT_ERR_NOT_REF)
973 				goto done;
974 			/* Try to look up references in a given namespace. */
975 		} else {
976 			err = got_reflist_insert(&new, refs, ref, repo,
977 			    cmp_cb, cmp_arg);
978 			if (err || new == NULL /* duplicate */)
979 				got_ref_close(ref);
980 			return err;
981 		}
982 	}
983 
984 	if (ref_namespace) {
985 		size_t len;
986 		/* Canonicalize the path to eliminate double-slashes if any. */
987 		if (asprintf(&abs_namespace, "/%s", ref_namespace) == -1) {
988 			err = got_error_from_errno("asprintf");
989 			goto done;
990 		}
991 		len = strlen(abs_namespace) + 1;
992 		buf = malloc(len);
993 		if (buf == NULL) {
994 			err = got_error_from_errno("malloc");
995 			goto done;
996 		}
997 		err = got_canonpath(abs_namespace, buf, len);
998 		if (err)
999 			goto done;
1000 		ondisk_ref_namespace = buf;
1001 		while (ondisk_ref_namespace[0] == '/')
1002 			ondisk_ref_namespace++;
1003 		if (strncmp(ondisk_ref_namespace, "refs/", 5) == 0)
1004 			ondisk_ref_namespace += 5;
1005 		else if (strcmp(ondisk_ref_namespace, "refs") == 0)
1006 			ondisk_ref_namespace = "";
1007 	}
1008 
1009 	/* Gather on-disk refs before parsing packed-refs. */
1010 	free(path_refs);
1011 	path_refs = get_refs_dir_path(repo, "");
1012 	if (path_refs == NULL) {
1013 		err = got_error_from_errno("get_refs_dir_path");
1014 		goto done;
1015 	}
1016 	err = gather_on_disk_refs(refs, path_refs,
1017 	    ondisk_ref_namespace ? ondisk_ref_namespace : "", repo,
1018 	    cmp_cb, cmp_arg);
1019 	if (err)
1020 		goto done;
1021 
1022 	/*
1023 	 * The packed-refs file may contain redundant entries, in which
1024 	 * case on-disk refs take precedence.
1025 	 */
1026 	packed_refs_path = got_repo_get_path_packed_refs(repo);
1027 	if (packed_refs_path == NULL) {
1028 		err = got_error_from_errno("got_repo_get_path_packed_refs");
1029 		goto done;
1030 	}
1031 
1032 	f = fopen(packed_refs_path, "r");
1033 	free(packed_refs_path);
1034 	if (f) {
1035 		size_t linesize = 0;
1036 		ssize_t linelen;
1037 		struct stat sb;
1038 
1039 		if (fstat(fileno(f), &sb) == -1) {
1040 			err = got_error_from_errno2("fstat", packed_refs_path);
1041 			goto done;
1042 		}
1043 		for (;;) {
1044 			linelen = getline(&line, &linesize, f);
1045 			if (linelen == -1) {
1046 				if (feof(f))
1047 					break;
1048 				err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
1049 				goto done;
1050 			}
1051 			if (linelen > 0 && line[linelen - 1] == '\n')
1052 				line[linelen - 1] = '\0';
1053 			err = parse_packed_ref_line(&ref, NULL, line,
1054 			    sb.st_mtime);
1055 			if (err)
1056 				goto done;
1057 			if (ref) {
1058 				if (ref_namespace) {
1059 					const char *name;
1060 					name = got_ref_get_name(ref);
1061 					if (!got_path_is_child(name,
1062 					    ref_namespace,
1063 					    strlen(ref_namespace))) {
1064 						got_ref_close(ref);
1065 						continue;
1066 					}
1067 				}
1068 				err = got_reflist_insert(&new, refs, ref, repo,
1069 				    cmp_cb, cmp_arg);
1070 				if (err || new == NULL /* duplicate */)
1071 					got_ref_close(ref);
1072 				if (err)
1073 					goto done;
1074 			}
1075 		}
1076 	}
1077 done:
1078 	free(abs_namespace);
1079 	free(buf);
1080 	free(line);
1081 	free(path_refs);
1082 	if (f && fclose(f) == EOF && err == NULL)
1083 		err = got_error_from_errno("fclose");
1084 	return err;
1085 }
1086 
1087 void
1088 got_ref_list_free(struct got_reflist_head *refs)
1089 {
1090 	struct got_reflist_entry *re;
1091 
1092 	while ((re = TAILQ_FIRST(refs))) {
1093 		TAILQ_REMOVE(refs, re, entry);
1094 		got_ref_close(re->ref);
1095 		free(re);
1096 	}
1097 
1098 }
1099 
1100 int
1101 got_ref_is_symbolic(struct got_reference *ref)
1102 {
1103 	return (ref->flags & GOT_REF_IS_SYMBOLIC);
1104 }
1105 
1106 const struct got_error *
1107 got_ref_change_ref(struct got_reference *ref, struct got_object_id *id)
1108 {
1109 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
1110 		return got_error(GOT_ERR_BAD_REF_TYPE);
1111 
1112 	memcpy(ref->ref.ref.sha1, id->sha1, sizeof(ref->ref.ref.sha1));
1113 	return NULL;
1114 }
1115 
1116 const struct got_error *
1117 got_ref_change_symref(struct got_reference *ref, const char *refname)
1118 {
1119 	char *new_name;
1120 
1121 	if ((ref->flags & GOT_REF_IS_SYMBOLIC) == 0)
1122 		return got_error(GOT_ERR_BAD_REF_TYPE);
1123 
1124 	new_name = strdup(refname);
1125 	if (new_name == NULL)
1126 		return got_error_from_errno("strdup");
1127 
1128 	free(ref->ref.symref.ref);
1129 	ref->ref.symref.ref = new_name;
1130 	return NULL;
1131 }
1132 
1133 const struct got_error *
1134 got_ref_change_symref_to_ref(struct got_reference *symref,
1135     struct got_object_id *id)
1136 {
1137 	if ((symref->flags & GOT_REF_IS_SYMBOLIC) == 0)
1138 		return got_error(GOT_ERR_BAD_REF_TYPE);
1139 
1140 	symref->ref.ref.name = symref->ref.symref.name;
1141 	memcpy(symref->ref.ref.sha1, id->sha1, SHA1_DIGEST_LENGTH);
1142 	symref->flags &= ~GOT_REF_IS_SYMBOLIC;
1143 	return NULL;
1144 }
1145 
1146 const struct got_error *
1147 got_ref_write(struct got_reference *ref, struct got_repository *repo)
1148 {
1149 	const struct got_error *err = NULL, *unlock_err = NULL;
1150 	const char *name = got_ref_get_name(ref);
1151 	char *path_refs = NULL, *path = NULL, *tmppath = NULL;
1152 	struct got_lockfile *lf = NULL;
1153 	FILE *f = NULL;
1154 	size_t n;
1155 	struct stat sb;
1156 
1157 	path_refs = get_refs_dir_path(repo, name);
1158 	if (path_refs == NULL) {
1159 		err = got_error_from_errno2("get_refs_dir_path", name);
1160 		goto done;
1161 	}
1162 
1163 	if (asprintf(&path, "%s/%s", path_refs, name) == -1) {
1164 		err = got_error_from_errno("asprintf");
1165 		goto done;
1166 	}
1167 
1168 	err = got_opentemp_named(&tmppath, &f, path);
1169 	if (err) {
1170 		char *parent;
1171 		if (!(err->code == GOT_ERR_ERRNO && errno == ENOENT))
1172 			goto done;
1173 		err = got_path_dirname(&parent, path);
1174 		if (err)
1175 			goto done;
1176 		err = got_path_mkdir(parent);
1177 		free(parent);
1178 		if (err)
1179 			goto done;
1180 		err = got_opentemp_named(&tmppath, &f, path);
1181 		if (err)
1182 			goto done;
1183 	}
1184 
1185 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
1186 		n = fprintf(f, "ref: %s\n", ref->ref.symref.ref);
1187 		if (n != strlen(ref->ref.symref.ref) + 6) {
1188 			err = got_ferror(f, GOT_ERR_IO);
1189 			goto done;
1190 		}
1191 	} else {
1192 		char hex[SHA1_DIGEST_STRING_LENGTH];
1193 		if (got_sha1_digest_to_str(ref->ref.ref.sha1, hex,
1194 		    sizeof(hex)) == NULL) {
1195 			err = got_error(GOT_ERR_BAD_REF_DATA);
1196 			goto done;
1197 		}
1198 		n = fprintf(f, "%s\n", hex);
1199 		if (n != sizeof(hex)) {
1200 			err = got_ferror(f, GOT_ERR_IO);
1201 			goto done;
1202 		}
1203 	}
1204 
1205 	if (ref->lf == NULL) {
1206 		err = got_lockfile_lock(&lf, path, -1);
1207 		if (err)
1208 			goto done;
1209 	}
1210 
1211 	/* XXX: check if old content matches our expectations? */
1212 
1213 	if (stat(path, &sb) != 0) {
1214 		if (errno != ENOENT) {
1215 			err = got_error_from_errno2("stat", path);
1216 			goto done;
1217 		}
1218 		sb.st_mode = GOT_DEFAULT_FILE_MODE;
1219 	}
1220 
1221 	if (fchmod(fileno(f), sb.st_mode) != 0) {
1222 		err = got_error_from_errno2("fchmod", tmppath);
1223 		goto done;
1224 	}
1225 
1226 	if (rename(tmppath, path) != 0) {
1227 		err = got_error_from_errno3("rename", tmppath, path);
1228 		goto done;
1229 	}
1230 	free(tmppath);
1231 	tmppath = NULL;
1232 
1233 	if (stat(path, &sb) == -1) {
1234 		err = got_error_from_errno2("stat", path);
1235 		goto done;
1236 	}
1237 	ref->mtime = sb.st_mtime;
1238 done:
1239 	if (ref->lf == NULL && lf)
1240 		unlock_err = got_lockfile_unlock(lf, -1);
1241 	if (f) {
1242 		if (fclose(f) == EOF && err == NULL)
1243 			err = got_error_from_errno("fclose");
1244 	}
1245 	free(path_refs);
1246 	free(path);
1247 	if (tmppath) {
1248 		if (unlink(tmppath) != 0 && err == NULL)
1249 			err = got_error_from_errno2("unlink", tmppath);
1250 		free(tmppath);
1251 	}
1252 	return err ? err : unlock_err;
1253 }
1254 
1255 static const struct got_error *
1256 delete_packed_ref(struct got_reference *delref, struct got_repository *repo)
1257 {
1258 	const struct got_error *err = NULL, *unlock_err = NULL;
1259 	struct got_lockfile *lf = NULL;
1260 	FILE *f = NULL, *tmpf = NULL;
1261 	char *line = NULL, *packed_refs_path, *tmppath = NULL;
1262 	size_t linesize = 0;
1263 	struct got_reflist_head refs;
1264 	int found_delref = 0;
1265 
1266 	/* The packed-refs file does not cotain symbolic references. */
1267 	if (delref->flags & GOT_REF_IS_SYMBOLIC)
1268 		return got_error(GOT_ERR_BAD_REF_DATA);
1269 
1270 	TAILQ_INIT(&refs);
1271 
1272 	packed_refs_path = got_repo_get_path_packed_refs(repo);
1273 	if (packed_refs_path == NULL)
1274 		return got_error_from_errno("got_repo_get_path_packed_refs");
1275 
1276 	err = got_opentemp_named(&tmppath, &tmpf, packed_refs_path);
1277 	if (err)
1278 		goto done;
1279 
1280 	if (delref->lf == NULL) {
1281 		err = got_lockfile_lock(&lf, packed_refs_path, -1);
1282 		if (err)
1283 			goto done;
1284 	}
1285 
1286 	f = fopen(packed_refs_path, "r");
1287 	if (f == NULL) {
1288 		err = got_error_from_errno2("fopen", packed_refs_path);
1289 		goto done;
1290 	}
1291 	for (;;) {
1292 		ssize_t linelen;
1293 		struct got_reference *ref;
1294 		struct got_reflist_entry *new;
1295 
1296 		linelen = getline(&line, &linesize, f);
1297 		if (linelen == -1) {
1298 			if (feof(f))
1299 				break;
1300 			err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
1301 			goto done;
1302 		}
1303 		if (linelen > 0 && line[linelen - 1] == '\n')
1304 			line[linelen - 1] = '\0';
1305 		err = parse_packed_ref_line(&ref, NULL, line, 0);
1306 		if (err)
1307 			goto done;
1308 		if (ref == NULL)
1309 			continue;
1310 
1311 		if (strcmp(ref->ref.ref.name, delref->ref.ref.name) == 0 &&
1312 		    memcmp(ref->ref.ref.sha1, delref->ref.ref.sha1,
1313 		    sizeof(delref->ref.ref.sha1)) == 0) {
1314 			found_delref = 1;
1315 			got_ref_close(ref);
1316 			continue;
1317 		}
1318 
1319 		err = got_reflist_insert(&new, &refs, ref, repo,
1320 		    got_ref_cmp_by_name, NULL);
1321 		if (err || new == NULL /* duplicate */)
1322 			got_ref_close(ref);
1323 		if (err)
1324 			goto done;
1325 	}
1326 
1327 	if (found_delref) {
1328 		struct got_reflist_entry *re;
1329 		size_t n;
1330 		struct stat sb;
1331 
1332 		n = fprintf(tmpf, "%s\n", GOT_PACKED_REFS_HEADER);
1333 		if (n != sizeof(GOT_PACKED_REFS_HEADER)) {
1334 			err = got_ferror(f, GOT_ERR_IO);
1335 			goto done;
1336 		}
1337 
1338 		TAILQ_FOREACH(re, &refs, entry) {
1339 			uint8_t hex[SHA1_DIGEST_STRING_LENGTH];
1340 
1341 			if (got_sha1_digest_to_str(re->ref->ref.ref.sha1, hex,
1342 			    sizeof(hex)) == NULL) {
1343 				err = got_error(GOT_ERR_BAD_REF_DATA);
1344 				goto done;
1345 			}
1346 			n = fprintf(tmpf, "%s ", hex);
1347 			if (n != sizeof(hex)) {
1348 				err = got_ferror(f, GOT_ERR_IO);
1349 				goto done;
1350 			}
1351 			n = fprintf(tmpf, "%s\n", re->ref->ref.ref.name);
1352 			if (n != strlen(re->ref->ref.ref.name) + 1) {
1353 				err = got_ferror(f, GOT_ERR_IO);
1354 				goto done;
1355 			}
1356 		}
1357 
1358 		if (fflush(tmpf) != 0) {
1359 			err = got_error_from_errno("fflush");
1360 			goto done;
1361 		}
1362 
1363 		if (fstat(fileno(f), &sb) != 0) {
1364 			if (errno != ENOENT) {
1365 				err = got_error_from_errno2("fstat",
1366 				    packed_refs_path);
1367 				goto done;
1368 			}
1369 			sb.st_mode = GOT_DEFAULT_FILE_MODE;
1370 		}
1371 
1372 		if (fchmod(fileno(tmpf), sb.st_mode) != 0) {
1373 			err = got_error_from_errno2("fchmod", tmppath);
1374 			goto done;
1375 		}
1376 
1377 		if (rename(tmppath, packed_refs_path) != 0) {
1378 			err = got_error_from_errno3("rename", tmppath,
1379 			    packed_refs_path);
1380 			goto done;
1381 		}
1382 	}
1383 done:
1384 	if (delref->lf == NULL && lf)
1385 		unlock_err = got_lockfile_unlock(lf, -1);
1386 	if (f) {
1387 		if (fclose(f) == EOF && err == NULL)
1388 			err = got_error_from_errno("fclose");
1389 	}
1390 	if (tmpf) {
1391 		unlink(tmppath);
1392 		if (fclose(tmpf) == EOF && err == NULL)
1393 			err = got_error_from_errno("fclose");
1394 	}
1395 	free(tmppath);
1396 	free(packed_refs_path);
1397 	free(line);
1398 	got_ref_list_free(&refs);
1399 	return err ? err : unlock_err;
1400 }
1401 
1402 static const struct got_error *
1403 delete_loose_ref(struct got_reference *ref, struct got_repository *repo)
1404 {
1405 	const struct got_error *err = NULL, *unlock_err = NULL;
1406 	const char *name = got_ref_get_name(ref);
1407 	char *path_refs = NULL, *path = NULL;
1408 	struct got_lockfile *lf = NULL;
1409 
1410 	path_refs = get_refs_dir_path(repo, name);
1411 	if (path_refs == NULL) {
1412 		err = got_error_from_errno2("get_refs_dir_path", name);
1413 		goto done;
1414 	}
1415 
1416 	if (asprintf(&path, "%s/%s", path_refs, name) == -1) {
1417 		err = got_error_from_errno("asprintf");
1418 		goto done;
1419 	}
1420 
1421 	if (ref->lf == NULL) {
1422 		err = got_lockfile_lock(&lf, path, -1);
1423 		if (err)
1424 			goto done;
1425 	}
1426 
1427 	/* XXX: check if old content matches our expectations? */
1428 
1429 	if (unlink(path) != 0)
1430 		err = got_error_from_errno2("unlink", path);
1431 done:
1432 	if (ref->lf == NULL && lf)
1433 		unlock_err = got_lockfile_unlock(lf, -1);
1434 
1435 	free(path_refs);
1436 	free(path);
1437 	return err ? err : unlock_err;
1438 }
1439 
1440 const struct got_error *
1441 got_ref_delete(struct got_reference *ref, struct got_repository *repo)
1442 {
1443 	const struct got_error *err = NULL;
1444 	struct got_reference *ref2;
1445 
1446 	if (ref->flags & GOT_REF_IS_PACKED) {
1447 		err = delete_packed_ref(ref, repo);
1448 		if (err)
1449 			return err;
1450 
1451 		err = got_ref_open(&ref2, repo, got_ref_get_name(ref), 0);
1452 		if (err) {
1453 			if (err->code == GOT_ERR_NOT_REF)
1454 				return NULL;
1455 			return err;
1456 		}
1457 
1458 		err = delete_loose_ref(ref2, repo);
1459 		got_ref_close(ref2);
1460 		return err;
1461 	} else {
1462 		err = delete_loose_ref(ref, repo);
1463 		if (err)
1464 			return err;
1465 
1466 		err = got_ref_open(&ref2, repo, got_ref_get_name(ref), 0);
1467 		if (err) {
1468 			if (err->code == GOT_ERR_NOT_REF)
1469 				return NULL;
1470 			return err;
1471 		}
1472 
1473 		err = delete_packed_ref(ref2, repo);
1474 		got_ref_close(ref2);
1475 		return err;
1476 	}
1477 }
1478 
1479 const struct got_error *
1480 got_ref_unlock(struct got_reference *ref)
1481 {
1482 	const struct got_error *err;
1483 	err = got_lockfile_unlock(ref->lf, -1);
1484 	ref->lf = NULL;
1485 	return err;
1486 }
1487 
1488 struct got_reflist_object_id_map {
1489 	struct got_object_idset *idset;
1490 };
1491 
1492 struct got_reflist_object_id_map_entry {
1493 	struct got_reflist_head refs;
1494 };
1495 
1496 static const struct got_error *
1497 add_object_id_map_entry(struct got_object_idset *idset,
1498     struct got_object_id *id, struct got_reflist_entry *re)
1499 {
1500 	const struct got_error *err = NULL;
1501 	struct got_reflist_object_id_map_entry *ent;
1502 	struct got_reflist_entry *new;
1503 
1504 	ent = got_object_idset_get(idset, id);
1505 	if (ent == NULL) {
1506 		ent = malloc(sizeof(*ent));
1507 		if (ent == NULL)
1508 			return got_error_from_errno("malloc");
1509 
1510 		TAILQ_INIT(&ent->refs);
1511 		err = got_object_idset_add(idset, id, ent);
1512 		if (err)
1513 			return err;
1514 	}
1515 
1516 	err = got_reflist_entry_dup(&new, re);
1517 	if (err)
1518 		return err;
1519 
1520 	TAILQ_INSERT_TAIL(&ent->refs, new, entry);
1521 	return NULL;
1522 }
1523 
1524 const struct got_error *
1525 got_reflist_object_id_map_create(struct got_reflist_object_id_map **map,
1526     struct got_reflist_head *refs, struct got_repository *repo)
1527 {
1528 	const struct got_error *err = NULL;
1529 	struct got_object_idset *idset;
1530 	struct got_object_id *id = NULL;
1531 	struct got_reflist_entry *re;
1532 
1533 	idset = got_object_idset_alloc();
1534 	if (idset == NULL)
1535 		return got_error_from_errno("got_object_idset_alloc");
1536 
1537 	*map = malloc(sizeof(**map));
1538 	if (*map == NULL) {
1539 		got_object_idset_free(idset);
1540 		return got_error_from_errno("malloc");
1541 	}
1542 	(*map)->idset = idset;
1543 
1544 	TAILQ_FOREACH(re, refs, entry) {
1545 		struct got_tag_object *tag = NULL;
1546 
1547 		err = got_ref_resolve(&id, repo, re->ref);
1548 		if (err)
1549 			goto done;
1550 
1551 		err = add_object_id_map_entry(idset, id, re);
1552 		if (err)
1553 			goto done;
1554 
1555 		if (strstr(got_ref_get_name(re->ref), "/tags/") == NULL) {
1556 			free(id);
1557 			id = NULL;
1558 			continue;
1559 		}
1560 
1561 		err = got_object_open_as_tag(&tag, repo, id);
1562 		if (err) {
1563 			if (err->code != GOT_ERR_OBJ_TYPE)
1564 				goto done;
1565 			/* Ref points at something other than a tag. */
1566 			err = NULL;
1567 			tag = NULL;
1568 			free(id);
1569 			id = NULL;
1570 			continue;
1571 		}
1572 
1573 		err = add_object_id_map_entry(idset,
1574 		    got_object_tag_get_object_id(tag), re);
1575 		got_object_tag_close(tag);
1576 		if (err)
1577 			goto done;
1578 
1579 		free(id);
1580 		id = NULL;
1581 	}
1582 done:
1583 	free(id);
1584 	if (err) {
1585 		got_reflist_object_id_map_free(*map);
1586 		*map = NULL;
1587 	}
1588 	return err;
1589 }
1590 
1591 struct got_reflist_head *
1592 got_reflist_object_id_map_lookup(struct got_reflist_object_id_map *map,
1593     struct got_object_id *id)
1594 {
1595 	struct got_reflist_object_id_map_entry *ent;
1596 	ent = got_object_idset_get(map->idset, id);
1597 	if (ent)
1598 		return &ent->refs;
1599 	return NULL;
1600 }
1601 
1602 static const struct got_error *
1603 free_id_map_entry(struct got_object_id *id, void *data, void *arg)
1604 {
1605 	struct got_reflist_object_id_map_entry *ent = data;
1606 
1607 	got_ref_list_free(&ent->refs);
1608 	free(ent);
1609 	return NULL;
1610 }
1611 
1612 void
1613 got_reflist_object_id_map_free(struct got_reflist_object_id_map *map)
1614 {
1615 	got_object_idset_for_each(map->idset, free_id_map_entry, NULL);
1616 	got_object_idset_free(map->idset);
1617 	free(map);
1618 }