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Date:: Wed Sep 9 19:35:32 2020 UTC
Message:: do not rely on <zlib.h> to pull in <unistd.h> ok stsp
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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_lockfile.h"
47 
48 #ifndef nitems
49 #define nitems(_a) (sizeof(_a) / sizeof((_a)[0]))
50 #endif
51 
52 #define GOT_REF_HEADS	"heads"
53 #define GOT_REF_TAGS	"tags"
54 #define GOT_REF_REMOTES	"remotes"
55 
56 /*
57  * We do not resolve tags yet, and don't yet care about sorting refs either,
58  * so packed-refs files we write contain a minimal header which disables all
59  * packed-refs "traits" supported by Git.
60  */
61 #define GOT_PACKED_REFS_HEADER	"# pack-refs with:"
62 
63 /* A symbolic reference. */
64 struct got_symref {
65 	char *name;
66 	char *ref;
67 };
68 
69 #define GOT_REF_RECURSE_MAX	20
70 
71 /* A non-symbolic reference (there is no better designation). */
72 struct got_ref {
73 	char *name;
74 	u_int8_t sha1[SHA1_DIGEST_LENGTH];
75 };
76 
77 /* A reference which points to an arbitrary object. */
78 struct got_reference {
79 	unsigned int flags;
80 #define GOT_REF_IS_SYMBOLIC	0x01
81 #define GOT_REF_IS_PACKED	0x02
82 
83 	union {
84 		struct got_ref ref;
85 		struct got_symref symref;
86 	} ref;
87 
88 	struct got_lockfile *lf;
89 };
90 
91 static const struct got_error *
92 alloc_ref(struct got_reference **ref, const char *name,
93     struct got_object_id *id, int flags)
94 {
95 	const struct got_error *err = NULL;
96 
97 	*ref = calloc(1, sizeof(**ref));
98 	if (*ref == NULL)
99 		return got_error_from_errno("calloc");
100 
101 	memcpy((*ref)->ref.ref.sha1, id->sha1, sizeof((*ref)->ref.ref.sha1));
102 	(*ref)->flags = flags;
103 	(*ref)->ref.ref.name = strdup(name);
104 	if ((*ref)->ref.ref.name == NULL) {
105 		err = got_error_from_errno("strdup");
106 		got_ref_close(*ref);
107 		*ref = NULL;
108 	}
109 	return err;
110 }
111 
112 static const struct got_error *
113 alloc_symref(struct got_reference **ref, const char *name,
114     const char *target_ref, int flags)
115 {
116 	const struct got_error *err = NULL;
117 
118 	*ref = calloc(1, sizeof(**ref));
119 	if (*ref == NULL)
120 		return got_error_from_errno("calloc");
121 
122 	(*ref)->flags = GOT_REF_IS_SYMBOLIC | flags;
123 	(*ref)->ref.symref.name = strdup(name);
124 	if ((*ref)->ref.symref.name == NULL) {
125 		err = got_error_from_errno("strdup");
126 		got_ref_close(*ref);
127 		*ref = NULL;
128 		return err;
129 	}
130 	(*ref)->ref.symref.ref = strdup(target_ref);
131 	if ((*ref)->ref.symref.ref == NULL) {
132 		err = got_error_from_errno("strdup");
133 		got_ref_close(*ref);
134 		*ref = NULL;
135 	}
136 	return err;
137 }
138 
139 static const struct got_error *
140 parse_symref(struct got_reference **ref, const char *name, const char *line)
141 {
142 	if (line[0] == '\0')
143 		return got_error(GOT_ERR_BAD_REF_DATA);
144 
145 	return alloc_symref(ref, name, line, 0);
146 }
147 
148 static const struct got_error *
149 parse_ref_line(struct got_reference **ref, const char *name, const char *line)
150 {
151 	struct got_object_id id;
152 
153 	if (strncmp(line, "ref: ", 5) == 0) {
154 		line += 5;
155 		return parse_symref(ref, name, line);
156 	}
157 
158 	if (!got_parse_sha1_digest(id.sha1, line))
159 		return got_error(GOT_ERR_BAD_REF_DATA);
160 
161 	return alloc_ref(ref, name, &id, 0);
162 }
163 
164 static const struct got_error *
165 parse_ref_file(struct got_reference **ref, const char *name,
166     const char *absname, const char *abspath, int lock)
167 {
168 	const struct got_error *err = NULL;
169 	FILE *f;
170 	char *line = NULL;
171 	size_t linesize = 0;
172 	ssize_t linelen;
173 	struct got_lockfile *lf = NULL;
174 
175 	if (lock) {
176 		err = got_lockfile_lock(&lf, abspath);
177 		if (err) {
178 			if (err->code == GOT_ERR_ERRNO && errno == ENOENT)
179 				err = got_error_not_ref(name);
180 			return err;
181 		}
182 	}
183 
184 	f = fopen(abspath, "rb");
185 	if (f == NULL) {
186 		if (errno != ENOTDIR && errno != ENOENT)
187 			err = got_error_from_errno2("fopen", abspath);
188 		else
189 			err = got_error_not_ref(name);
190 		if (lock)
191 			got_lockfile_unlock(lf);
192 		return err;
193 	}
194 
195 	linelen = getline(&line, &linesize, f);
196 	if (linelen == -1) {
197 		if (feof(f))
198 			err = NULL; /* ignore empty files (could be locks) */
199 		else {
200 			if (errno == EISDIR)
201 				err = got_error(GOT_ERR_NOT_REF);
202 			else if (ferror(f))
203 				err = got_ferror(f, GOT_ERR_IO);
204 			else
205 				err = got_error_from_errno2("getline", abspath);
206 		}
207 		if (lock)
208 			got_lockfile_unlock(lf);
209 		goto done;
210 	}
211 	while (linelen > 0 && line[linelen - 1] == '\n') {
212 		line[linelen - 1] = '\0';
213 		linelen--;
214 	}
215 
216 	err = parse_ref_line(ref, absname, line);
217 	if (lock) {
218 		if (err)
219 			got_lockfile_unlock(lf);
220 		else {
221 			if (*ref)
222 				(*ref)->lf = lf;
223 			else
224 				got_lockfile_unlock(lf);
225 		}
226 	}
227 done:
228 	free(line);
229 	if (fclose(f) != 0 && err == NULL) {
230 		err = got_error_from_errno("fclose");
231 		if (*ref) {
232 			if (lock)
233 				got_ref_unlock(*ref);
234 			got_ref_close(*ref);
235 			*ref = NULL;
236 		}
237 	}
238 	return err;
239 }
240 
241 static int
242 is_well_known_ref(const char *refname)
243 {
244 	return (strcmp(refname, GOT_REF_HEAD) == 0 ||
245 	    strcmp(refname, GOT_REF_ORIG_HEAD) == 0 ||
246 	    strcmp(refname, GOT_REF_MERGE_HEAD) == 0 ||
247 	    strcmp(refname, GOT_REF_FETCH_HEAD) == 0);
248 }
249 
250 static char *
251 get_refs_dir_path(struct got_repository *repo, const char *refname)
252 {
253 	if (is_well_known_ref(refname) || strncmp(refname, "refs/", 5) == 0)
254 		return strdup(got_repo_get_path_git_dir(repo));
255 
256 	return got_repo_get_path_refs(repo);
257 }
258 
259 static int
260 is_valid_ref_name(const char *name)
261 {
262 	const char *s, *seg;
263 	const char forbidden[] = { ' ', '~', '^', ':', '?', '*', '[' , '\\' };
264 	const char *forbidden_seq[] = { "//", "..", "@{" };
265 	const char *lfs = GOT_LOCKFILE_SUFFIX;
266 	const size_t lfs_len = sizeof(GOT_LOCKFILE_SUFFIX) - 1;
267 	int i;
268 
269 	if (name[0] == '@' && name[1] == '\0')
270 		return 0;
271 
272 	s = name;
273 	seg = s;
274 	if (seg[0] == '\0' || seg[0] == '.' || seg[0] == '/')
275 		return 0;
276 	while (*s) {
277 		for (i = 0; i < nitems(forbidden); i++) {
278 			if (*s == forbidden[i])
279 				return 0;
280 		}
281 		for (i = 0; i < nitems(forbidden_seq); i++) {
282 			if (s[0] == forbidden_seq[i][0] &&
283 			    s[1] == forbidden_seq[i][1])
284 				return 0;
285 		}
286 		if (iscntrl((unsigned char)s[0]))
287 			return 0;
288 		if (s[0] == '.' && s[1] == '\0')
289 			return 0;
290 		if (*s == '/') {
291 			const char *nextseg = s + 1;
292 			if (nextseg[0] == '\0' || nextseg[0] == '.' ||
293 			    nextseg[0] == '/')
294 				return 0;
295 			if (seg <= s - lfs_len &&
296 			    strncmp(s - lfs_len, lfs, lfs_len) == 0)
297 				return 0;
298 			seg = nextseg;
299 		}
300 		s++;
301 	}
302 
303 	if (seg <= s - lfs_len &&
304 	    strncmp(s - lfs_len, lfs, lfs_len) == 0)
305 		return 0;
306 
307 	return 1;
308 }
309 
310 const struct got_error *
311 got_ref_alloc(struct got_reference **ref, const char *name,
312     struct got_object_id *id)
313 {
314 	if (!is_valid_ref_name(name))
315 		return got_error_path(name, GOT_ERR_BAD_REF_NAME);
316 
317 	return alloc_ref(ref, name, id, 0);
318 }
319 
320 const struct got_error *
321 got_ref_alloc_symref(struct got_reference **ref, const char *name,
322 	struct got_reference *target_ref)
323 {
324 	if (!is_valid_ref_name(name))
325 		return got_error_path(name, GOT_ERR_BAD_REF_NAME);
326 
327 	return alloc_symref(ref, name, got_ref_get_name(target_ref), 0);
328 }
329 
330 static const struct got_error *
331 parse_packed_ref_line(struct got_reference **ref, const char *abs_refname,
332     const char *line)
333 {
334 	struct got_object_id id;
335 	const char *name;
336 
337 	*ref = NULL;
338 
339 	if (line[0] == '#' || line[0] == '^')
340 		return NULL;
341 
342 	if (!got_parse_sha1_digest(id.sha1, line))
343 		return got_error(GOT_ERR_BAD_REF_DATA);
344 
345 	if (abs_refname) {
346 		if (strcmp(line + SHA1_DIGEST_STRING_LENGTH, abs_refname) != 0)
347 			return NULL;
348 		name = abs_refname;
349 	} else
350 		name = line + SHA1_DIGEST_STRING_LENGTH;
351 
352 	return alloc_ref(ref, name, &id, GOT_REF_IS_PACKED);
353 }
354 
355 static const struct got_error *
356 open_packed_ref(struct got_reference **ref, FILE *f, const char **subdirs,
357     int nsubdirs, const char *refname)
358 {
359 	const struct got_error *err = NULL;
360 	char *abs_refname;
361 	char *line;
362 	size_t len;
363 	const char delim[3] = {'\0', '\0', '\0'};
364 	int i, ref_is_absolute = (strncmp(refname, "refs/", 5) == 0);
365 
366 	*ref = NULL;
367 
368 	if (ref_is_absolute)
369 		abs_refname = (char *)refname;
370 	do {
371 		line = fparseln(f, &len, NULL, delim, 0);
372 		if (line == NULL) {
373 			if (feof(f))
374 				break;
375 			err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
376 			break;
377 		}
378 		for (i = 0; i < nsubdirs; i++) {
379 			if (!ref_is_absolute &&
380 			    asprintf(&abs_refname, "refs/%s/%s", subdirs[i],
381 			    refname) == -1)
382 				return got_error_from_errno("asprintf");
383 			err = parse_packed_ref_line(ref, abs_refname, line);
384 			if (!ref_is_absolute)
385 				free(abs_refname);
386 			if (err || *ref != NULL)
387 				break;
388 		}
389 		free(line);
390 		if (err)
391 			break;
392 	} while (*ref == NULL);
393 
394 	return err;
395 }
396 
397 static const struct got_error *
398 open_ref(struct got_reference **ref, const char *path_refs, const char *subdir,
399     const char *name, int lock)
400 {
401 	const struct got_error *err = NULL;
402 	char *path = NULL;
403 	char *absname = NULL;
404 	int ref_is_absolute = (strncmp(name, "refs/", 5) == 0);
405 	int ref_is_well_known = (subdir[0] == '\0' && is_well_known_ref(name));
406 
407 	*ref = NULL;
408 
409 	if (ref_is_absolute || ref_is_well_known) {
410 		if (asprintf(&path, "%s/%s", path_refs, name) == -1)
411 			return got_error_from_errno("asprintf");
412 		absname = (char *)name;
413 	} else {
414 		if (asprintf(&path, "%s/%s%s%s", path_refs, subdir,
415 		    subdir[0] ? "/" : "", name) == -1)
416 			return got_error_from_errno("asprintf");
417 
418 		if (asprintf(&absname, "refs/%s%s%s",
419 		    subdir, subdir[0] ? "/" : "", name) == -1) {
420 			err = got_error_from_errno("asprintf");
421 			goto done;
422 		}
423 	}
424 
425 	err = parse_ref_file(ref, name, absname, path, lock);
426 done:
427 	if (!ref_is_absolute && !ref_is_well_known)
428 		free(absname);
429 	free(path);
430 	return err;
431 }
432 
433 const struct got_error *
434 got_ref_open(struct got_reference **ref, struct got_repository *repo,
435    const char *refname, int lock)
436 {
437 	const struct got_error *err = NULL;
438 	char *path_refs = NULL;
439 	const char *subdirs[] = {
440 	    GOT_REF_HEADS, GOT_REF_TAGS, GOT_REF_REMOTES
441 	};
442 	int i, well_known = is_well_known_ref(refname);
443 	struct got_lockfile *lf = NULL;
444 
445 	*ref = NULL;
446 
447 	path_refs = get_refs_dir_path(repo, refname);
448 	if (path_refs == NULL) {
449 		err = got_error_from_errno2("get_refs_dir_path", refname);
450 		goto done;
451 	}
452 
453 	if (well_known) {
454 		err = open_ref(ref, path_refs, "", refname, lock);
455 	} else {
456 		char *packed_refs_path;
457 		FILE *f;
458 
459 		/* Search on-disk refs before packed refs! */
460 		for (i = 0; i < nitems(subdirs); i++) {
461 			err = open_ref(ref, path_refs, subdirs[i], refname,
462 			    lock);
463 			if ((err && err->code != GOT_ERR_NOT_REF) || *ref)
464 				goto done;
465 		}
466 
467 		packed_refs_path = got_repo_get_path_packed_refs(repo);
468 		if (packed_refs_path == NULL) {
469 			err = got_error_from_errno(
470 			    "got_repo_get_path_packed_refs");
471 			goto done;
472 		}
473 
474 		if (lock) {
475 			err = got_lockfile_lock(&lf, packed_refs_path);
476 			if (err)
477 				goto done;
478 		}
479 		f = fopen(packed_refs_path, "rb");
480 		free(packed_refs_path);
481 		if (f != NULL) {
482 			err = open_packed_ref(ref, f, subdirs, nitems(subdirs),
483 			    refname);
484 			if (!err) {
485 				if (fclose(f) != 0) {
486 					err = got_error_from_errno("fclose");
487 					got_ref_close(*ref);
488 					*ref = NULL;
489 				} else if (*ref)
490 					(*ref)->lf = lf;
491 			}
492 		}
493 	}
494 done:
495 	if (!err && *ref == NULL)
496 		err = got_error_not_ref(refname);
497 	if (err && lf)
498 		got_lockfile_unlock(lf);
499 	free(path_refs);
500 	return err;
501 }
502 
503 void
504 got_ref_close(struct got_reference *ref)
505 {
506 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
507 		free(ref->ref.symref.name);
508 		free(ref->ref.symref.ref);
509 	} else
510 		free(ref->ref.ref.name);
511 	free(ref);
512 }
513 
514 struct got_reference *
515 got_ref_dup(struct got_reference *ref)
516 {
517 	struct got_reference *ret;
518 
519 	ret = calloc(1, sizeof(*ret));
520 	if (ret == NULL)
521 		return NULL;
522 
523 	ret->flags = ref->flags;
524 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
525 		ret->ref.symref.name = strdup(ref->ref.symref.name);
526 		if (ret->ref.symref.name == NULL) {
527 			free(ret);
528 			return NULL;
529 		}
530 		ret->ref.symref.ref = strdup(ref->ref.symref.ref);
531 		if (ret->ref.symref.ref == NULL) {
532 			free(ret->ref.symref.name);
533 			free(ret);
534 			return NULL;
535 		}
536 	} else {
537 		ref->ref.ref.name = strdup(ref->ref.ref.name);
538 		if (ref->ref.ref.name == NULL) {
539 			free(ret);
540 			return NULL;
541 		}
542 		memcpy(ret->ref.ref.sha1, ref->ref.ref.sha1,
543 		    sizeof(ret->ref.ref.sha1));
544 	}
545 
546 	return ret;
547 }
548 
549 const struct got_error *
550 got_reflist_entry_dup(struct got_reflist_entry **newp,
551     struct got_reflist_entry *re)
552 {
553 	const struct got_error *err = NULL;
554 	struct got_reflist_entry *new;
555 
556 	*newp = NULL;
557 
558 	new = malloc(sizeof(*new));
559 	if (new == NULL)
560 		return got_error_from_errno("malloc");
561 
562 	new->ref = got_ref_dup(re->ref);
563 	if (new->ref == NULL) {
564 		err = got_error_from_errno("got_ref_dup");
565 		free(new);
566 		return err;
567 	}
568 
569 	new->id = got_object_id_dup(re->id);
570 	if (new->id == NULL) {
571 		err = got_error_from_errno("got_ref_dup");
572 		free(new->id);
573 		free(new);
574 		return err;
575 	}
576 
577 	*newp = new;
578 	return NULL;
579 }
580 
581 static const struct got_error *
582 resolve_symbolic_ref(struct got_reference **resolved,
583     struct got_repository *repo, struct got_reference *ref)
584 {
585 	struct got_reference *nextref;
586 	const struct got_error *err;
587 
588 	err = got_ref_open(&nextref, repo, ref->ref.symref.ref, 0);
589 	if (err)
590 		return err;
591 
592 	if (nextref->flags & GOT_REF_IS_SYMBOLIC)
593 		err = resolve_symbolic_ref(resolved, repo, nextref);
594 	else
595 		*resolved = got_ref_dup(nextref);
596 
597 	got_ref_close(nextref);
598 	return err;
599 }
600 
601 static const struct got_error *
602 ref_resolve(struct got_object_id **id, struct got_repository *repo,
603     struct got_reference *ref, int recursion)
604 {
605 	const struct got_error *err;
606 
607 	if (recursion <= 0)
608 		return got_error_msg(GOT_ERR_RECURSION,
609 		    "reference recursion limit reached");
610 
611 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
612 		struct got_reference *resolved = NULL;
613 		err = resolve_symbolic_ref(&resolved, repo, ref);
614 		if (err == NULL)
615 			err = ref_resolve(id, repo, resolved, --recursion);
616 		if (resolved)
617 			got_ref_close(resolved);
618 		return err;
619 	}
620 
621 	*id = calloc(1, sizeof(**id));
622 	if (*id == NULL)
623 		return got_error_from_errno("calloc");
624 	memcpy((*id)->sha1, ref->ref.ref.sha1, sizeof((*id)->sha1));
625 	return NULL;
626 }
627 
628 const struct got_error *
629 got_ref_resolve(struct got_object_id **id, struct got_repository *repo,
630     struct got_reference *ref)
631 {
632 	return ref_resolve(id, repo, ref, GOT_REF_RECURSE_MAX);
633 }
634 
635 char *
636 got_ref_to_str(struct got_reference *ref)
637 {
638 	char *str;
639 
640 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
641 		return strdup(ref->ref.symref.ref);
642 
643 	str = malloc(SHA1_DIGEST_STRING_LENGTH);
644 	if (str == NULL)
645 		return NULL;
646 
647 	if (got_sha1_digest_to_str(ref->ref.ref.sha1, str,
648 	    SHA1_DIGEST_STRING_LENGTH) == NULL) {
649 		free(str);
650 		return NULL;
651 	}
652 
653 	return str;
654 }
655 
656 const char *
657 got_ref_get_name(struct got_reference *ref)
658 {
659 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
660 		return ref->ref.symref.name;
661 
662 	return ref->ref.ref.name;
663 }
664 
665 const char *
666 got_ref_get_symref_target(struct got_reference *ref)
667 {
668 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
669 		return ref->ref.symref.ref;
670 
671 	return NULL;
672 }
673 
674 const struct got_error *
675 got_ref_cmp_by_name(void *arg, int *cmp, struct got_reference *re1,
676     struct got_reference* re2)
677 {
678 	const char *name1 = got_ref_get_name(re1);
679 	const char *name2 = got_ref_get_name(re2);
680 
681 	*cmp = got_path_cmp(name1, name2, strlen(name1), strlen(name2));
682 	return NULL;
683 }
684 
685 const struct got_error *
686 got_ref_cmp_tags(void *arg, int *cmp, struct got_reference *ref1,
687     struct got_reference *ref2)
688 {
689 	const struct got_error *err = NULL;
690 	struct got_repository *repo = arg;
691 	struct got_object_id *id1, *id2 = NULL;
692 	struct got_tag_object *tag1 = NULL, *tag2 = NULL;
693 	struct got_commit_object *commit1 = NULL, *commit2 = NULL;
694 	time_t time1, time2;
695 
696 	*cmp = 0;
697 
698 	err = got_ref_resolve(&id1, repo, ref1);
699 	if (err)
700 		return err;
701 	err = got_object_open_as_tag(&tag1, repo, id1);
702 	if (err) {
703 		if (err->code != GOT_ERR_OBJ_TYPE)
704 			goto done;
705 		/* "lightweight" tag */
706 		err = got_object_open_as_commit(&commit1, repo, id1);
707 		if (err)
708 			goto done;
709 		time1 = got_object_commit_get_committer_time(commit1);
710 	} else
711 		time1 = got_object_tag_get_tagger_time(tag1);
712 
713 	err = got_ref_resolve(&id2, repo, ref2);
714 	if (err)
715 		goto done;
716 	err = got_object_open_as_tag(&tag2, repo, id2);
717 	if (err) {
718 		if (err->code != GOT_ERR_OBJ_TYPE)
719 			goto done;
720 		/* "lightweight" tag */
721 		err = got_object_open_as_commit(&commit2, repo, id2);
722 		if (err)
723 			goto done;
724 		time2 = got_object_commit_get_committer_time(commit2);
725 	} else
726 		time2 = got_object_tag_get_tagger_time(tag2);
727 
728 	/* Put latest tags first. */
729 	if (time1 < time2)
730 		*cmp = 1;
731 	else if (time1 > time2)
732 		*cmp = -1;
733 	else
734 		err = got_ref_cmp_by_name(NULL, cmp, ref2, ref1);
735 done:
736 	free(id1);
737 	free(id2);
738 	if (tag1)
739 		got_object_tag_close(tag1);
740 	if (tag2)
741 		got_object_tag_close(tag2);
742 	if (commit1)
743 		got_object_commit_close(commit1);
744 	if (commit2)
745 		got_object_commit_close(commit2);
746 	return err;
747 }
748 
749 static const struct got_error *
750 insert_ref(struct got_reflist_entry **newp, struct got_reflist_head *refs,
751     struct got_reference *ref, struct got_repository *repo,
752     got_ref_cmp_cb cmp_cb, void *cmp_arg)
753 {
754 	const struct got_error *err;
755 	struct got_object_id *id;
756 	struct got_reflist_entry *new, *re, *prev = NULL;
757 	int cmp;
758 
759 	*newp = NULL;
760 
761 	err = got_ref_resolve(&id, repo, ref);
762 	if (err)
763 		return err;
764 
765 	new = malloc(sizeof(*new));
766 	if (new == NULL) {
767 		free(id);
768 		return got_error_from_errno("malloc");
769 	}
770 	new->ref = ref;
771 	new->id = id;
772 	*newp = new;
773 
774 	/*
775 	 * We must de-duplicate entries on insert because packed-refs may
776 	 * contain redundant entries. On-disk refs take precedence.
777 	 * This code assumes that on-disk revs are read before packed-refs.
778 	 * We're iterating the list anyway, so insert elements sorted by name.
779 	 */
780 	re = SIMPLEQ_FIRST(refs);
781 	while (re) {
782 		err = (*cmp_cb)(cmp_arg, &cmp, re->ref, new->ref);
783 		if (err)
784 			return err;
785 		if (cmp == 0) {
786 			/* duplicate */
787 			free(new->id);
788 			free(new);
789 			*newp = NULL;
790 			return NULL;
791 		} else if (cmp > 0) {
792 			if (prev)
793 				SIMPLEQ_INSERT_AFTER(refs, prev, new, entry);
794 			else
795 				SIMPLEQ_INSERT_HEAD(refs, new, entry);
796 			return NULL;
797 		} else {
798 			prev = re;
799 			re = SIMPLEQ_NEXT(re, entry);
800 		}
801 	}
802 
803 	SIMPLEQ_INSERT_TAIL(refs, new, entry);
804 	return NULL;
805 }
806 
807 static const struct got_error *
808 gather_on_disk_refs(struct got_reflist_head *refs, const char *path_refs,
809     const char *subdir, struct got_repository *repo,
810     got_ref_cmp_cb cmp_cb, void *cmp_arg)
811 {
812 	const struct got_error *err = NULL;
813 	DIR *d = NULL;
814 	char *path_subdir;
815 
816 	while (subdir[0] == '/')
817 		subdir++;
818 
819 	if (asprintf(&path_subdir, "%s/%s", path_refs, subdir) == -1)
820 		return got_error_from_errno("asprintf");
821 
822 	d = opendir(path_subdir);
823 	if (d == NULL)
824 		goto done;
825 
826 	for (;;) {
827 		struct dirent *dent;
828 		struct got_reference *ref;
829 		char *child;
830 		int type;
831 
832 		dent = readdir(d);
833 		if (dent == NULL)
834 			break;
835 
836 		if (strcmp(dent->d_name, ".") == 0 ||
837 		    strcmp(dent->d_name, "..") == 0)
838 			continue;
839 
840 		err = got_path_dirent_type(&type, path_subdir, dent);
841 		if (err)
842 			break;
843 
844 		switch (type) {
845 		case DT_REG:
846 			err = open_ref(&ref, path_refs, subdir, dent->d_name,
847 			    0);
848 			if (err)
849 				goto done;
850 			if (ref) {
851 				struct got_reflist_entry *new;
852 				err = insert_ref(&new, refs, ref, repo,
853 				    cmp_cb, cmp_arg);
854 				if (err || new == NULL /* duplicate */)
855 					got_ref_close(ref);
856 				if (err)
857 					goto done;
858 			}
859 			break;
860 		case DT_DIR:
861 			if (asprintf(&child, "%s%s%s", subdir,
862 			    subdir[0] == '\0' ? "" : "/", dent->d_name) == -1) {
863 				err = got_error_from_errno("asprintf");
864 				break;
865 			}
866 			err = gather_on_disk_refs(refs, path_refs, child, repo,
867 			    cmp_cb, cmp_arg);
868 			free(child);
869 			break;
870 		default:
871 			break;
872 		}
873 	}
874 done:
875 	if (d)
876 		closedir(d);
877 	free(path_subdir);
878 	return err;
879 }
880 
881 const struct got_error *
882 got_ref_list(struct got_reflist_head *refs, struct got_repository *repo,
883     const char *ref_namespace, got_ref_cmp_cb cmp_cb, void *cmp_arg)
884 {
885 	const struct got_error *err;
886 	char *packed_refs_path, *path_refs = NULL;
887 	char *abs_namespace = NULL;
888 	char *buf = NULL, *ondisk_ref_namespace = NULL;
889 	FILE *f = NULL;
890 	struct got_reference *ref;
891 	struct got_reflist_entry *new;
892 
893 	if (ref_namespace == NULL || ref_namespace[0] == '\0') {
894 		path_refs = get_refs_dir_path(repo, GOT_REF_HEAD);
895 		if (path_refs == NULL) {
896 			err = got_error_from_errno("get_refs_dir_path");
897 			goto done;
898 		}
899 		err = open_ref(&ref, path_refs, "", GOT_REF_HEAD, 0);
900 		if (err)
901 			goto done;
902 		err = insert_ref(&new, refs, ref, repo,
903 		    cmp_cb, cmp_arg);
904 		if (err || new == NULL /* duplicate */)
905 			got_ref_close(ref);
906 		if (err && err->code != GOT_ERR_NOT_REF)
907 			goto done;
908 	} else {
909 		/* Try listing a single reference. */
910 		const char *refname = ref_namespace;
911 		path_refs = get_refs_dir_path(repo, refname);
912 		if (path_refs == NULL) {
913 			err = got_error_from_errno("get_refs_dir_path");
914 			goto done;
915 		}
916 		err = open_ref(&ref, path_refs, "", refname, 0);
917 		if (err) {
918 			if (err->code != GOT_ERR_NOT_REF)
919 				goto done;
920 			/* Try to look up references in a given namespace. */
921 		} else {
922 			err = insert_ref(&new, refs, ref, repo,
923 			    cmp_cb, cmp_arg);
924 			if (err || new == NULL /* duplicate */)
925 				got_ref_close(ref);
926 			return err;
927 		}
928 	}
929 
930 	if (ref_namespace) {
931 		size_t len;
932 		/* Canonicalize the path to eliminate double-slashes if any. */
933 		if (asprintf(&abs_namespace, "/%s", ref_namespace) == -1) {
934 			err = got_error_from_errno("asprintf");
935 			goto done;
936 		}
937 		len = strlen(abs_namespace) + 1;
938 		buf = malloc(len);
939 		if (buf == NULL) {
940 			err = got_error_from_errno("malloc");
941 			goto done;
942 		}
943 		err = got_canonpath(abs_namespace, buf, len);
944 		if (err)
945 			goto done;
946 		ondisk_ref_namespace = buf;
947 		while (ondisk_ref_namespace[0] == '/')
948 			ondisk_ref_namespace++;
949 		if (strncmp(ondisk_ref_namespace, "refs/", 5) == 0)
950 			ondisk_ref_namespace += 5;
951 		else if (strcmp(ondisk_ref_namespace, "refs") == 0)
952 			ondisk_ref_namespace = "";
953 	}
954 
955 	/* Gather on-disk refs before parsing packed-refs. */
956 	free(path_refs);
957 	path_refs = get_refs_dir_path(repo, "");
958 	if (path_refs == NULL) {
959 		err = got_error_from_errno("get_refs_dir_path");
960 		goto done;
961 	}
962 	err = gather_on_disk_refs(refs, path_refs,
963 	    ondisk_ref_namespace ? ondisk_ref_namespace : "", repo,
964 	    cmp_cb, cmp_arg);
965 	if (err)
966 		goto done;
967 
968 	/*
969 	 * The packed-refs file may contain redundant entries, in which
970 	 * case on-disk refs take precedence.
971 	 */
972 	packed_refs_path = got_repo_get_path_packed_refs(repo);
973 	if (packed_refs_path == NULL) {
974 		err = got_error_from_errno("got_repo_get_path_packed_refs");
975 		goto done;
976 	}
977 
978 	f = fopen(packed_refs_path, "r");
979 	free(packed_refs_path);
980 	if (f) {
981 		char *line;
982 		size_t len;
983 		const char delim[3] = {'\0', '\0', '\0'};
984 		for (;;) {
985 			line = fparseln(f, &len, NULL, delim, 0);
986 			if (line == NULL) {
987 				if (feof(f))
988 					break;
989 				err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
990 				goto done;
991 			}
992 			err = parse_packed_ref_line(&ref, NULL, line);
993 			free(line);
994 			if (err)
995 				goto done;
996 			if (ref) {
997 				if (ref_namespace) {
998 					const char *name;
999 					name = got_ref_get_name(ref);
1000 					if (!got_path_is_child(name,
1001 					    ref_namespace,
1002 					    strlen(ref_namespace))) {
1003 						got_ref_close(ref);
1004 						continue;
1005 					}
1006 				}
1007 				err = insert_ref(&new, refs, ref, repo,
1008 				    cmp_cb, cmp_arg);
1009 				if (err || new == NULL /* duplicate */)
1010 					got_ref_close(ref);
1011 				if (err)
1012 					goto done;
1013 			}
1014 		}
1015 	}
1016 done:
1017 	free(abs_namespace);
1018 	free(buf);
1019 	free(path_refs);
1020 	if (f && fclose(f) != 0 && err == NULL)
1021 		err = got_error_from_errno("fclose");
1022 	return err;
1023 }
1024 
1025 void
1026 got_ref_list_free(struct got_reflist_head *refs)
1027 {
1028 	struct got_reflist_entry *re;
1029 
1030 	while (!SIMPLEQ_EMPTY(refs)) {
1031 		re = SIMPLEQ_FIRST(refs);
1032 		SIMPLEQ_REMOVE_HEAD(refs, entry);
1033 		got_ref_close(re->ref);
1034 		free(re->id);
1035 		free(re);
1036 	}
1037 
1038 }
1039 
1040 int
1041 got_ref_is_symbolic(struct got_reference *ref)
1042 {
1043 	return (ref->flags & GOT_REF_IS_SYMBOLIC);
1044 }
1045 
1046 const struct got_error *
1047 got_ref_change_ref(struct got_reference *ref, struct got_object_id *id)
1048 {
1049 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
1050 		return got_error(GOT_ERR_BAD_REF_TYPE);
1051 
1052 	memcpy(ref->ref.ref.sha1, id->sha1, sizeof(ref->ref.ref.sha1));
1053 	return NULL;
1054 }
1055 
1056 const struct got_error *
1057 got_ref_change_symref(struct got_reference *ref, const char *refname)
1058 {
1059 	char *new_name;
1060 
1061 	if ((ref->flags & GOT_REF_IS_SYMBOLIC) == 0)
1062 		return got_error(GOT_ERR_BAD_REF_TYPE);
1063 
1064 	new_name = strdup(refname);
1065 	if (new_name == NULL)
1066 		return got_error_from_errno("strdup");
1067 
1068 	free(ref->ref.symref.ref);
1069 	ref->ref.symref.ref = new_name;
1070 	return NULL;
1071 }
1072 
1073 const struct got_error *
1074 got_ref_change_symref_to_ref(struct got_reference *symref,
1075     struct got_object_id *id)
1076 {
1077 	if ((symref->flags & GOT_REF_IS_SYMBOLIC) == 0)
1078 		return got_error(GOT_ERR_BAD_REF_TYPE);
1079 
1080 	symref->ref.ref.name = symref->ref.symref.name;
1081 	memcpy(symref->ref.ref.sha1, id->sha1, SHA1_DIGEST_LENGTH);
1082 	symref->flags &= ~GOT_REF_IS_SYMBOLIC;
1083 	return NULL;
1084 }
1085 
1086 const struct got_error *
1087 got_ref_write(struct got_reference *ref, struct got_repository *repo)
1088 {
1089 	const struct got_error *err = NULL, *unlock_err = NULL;
1090 	const char *name = got_ref_get_name(ref);
1091 	char *path_refs = NULL, *path = NULL, *tmppath = NULL;
1092 	struct got_lockfile *lf = NULL;
1093 	FILE *f = NULL;
1094 	size_t n;
1095 	struct stat sb;
1096 
1097 	path_refs = get_refs_dir_path(repo, name);
1098 	if (path_refs == NULL) {
1099 		err = got_error_from_errno2("get_refs_dir_path", name);
1100 		goto done;
1101 	}
1102 
1103 	if (asprintf(&path, "%s/%s", path_refs, name) == -1) {
1104 		err = got_error_from_errno("asprintf");
1105 		goto done;
1106 	}
1107 
1108 	err = got_opentemp_named(&tmppath, &f, path);
1109 	if (err) {
1110 		char *parent;
1111 		if (!(err->code == GOT_ERR_ERRNO && errno == ENOENT))
1112 			goto done;
1113 		err = got_path_dirname(&parent, path);
1114 		if (err)
1115 			goto done;
1116 		err = got_path_mkdir(parent);
1117 		free(parent);
1118 		if (err)
1119 			goto done;
1120 		err = got_opentemp_named(&tmppath, &f, path);
1121 		if (err)
1122 			goto done;
1123 	}
1124 
1125 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
1126 		n = fprintf(f, "ref: %s\n", ref->ref.symref.ref);
1127 		if (n != strlen(ref->ref.symref.ref) + 6) {
1128 			err = got_ferror(f, GOT_ERR_IO);
1129 			goto done;
1130 		}
1131 	} else {
1132 		char hex[SHA1_DIGEST_STRING_LENGTH];
1133 		if (got_sha1_digest_to_str(ref->ref.ref.sha1, hex,
1134 		    sizeof(hex)) == NULL) {
1135 			err = got_error(GOT_ERR_BAD_REF_DATA);
1136 			goto done;
1137 		}
1138 		n = fprintf(f, "%s\n", hex);
1139 		if (n != sizeof(hex)) {
1140 			err = got_ferror(f, GOT_ERR_IO);
1141 			goto done;
1142 		}
1143 	}
1144 
1145 	if (ref->lf == NULL) {
1146 		err = got_lockfile_lock(&lf, path);
1147 		if (err)
1148 			goto done;
1149 	}
1150 
1151 	/* XXX: check if old content matches our expectations? */
1152 
1153 	if (stat(path, &sb) != 0) {
1154 		if (errno != ENOENT) {
1155 			err = got_error_from_errno2("stat", path);
1156 			goto done;
1157 		}
1158 		sb.st_mode = GOT_DEFAULT_FILE_MODE;
1159 	}
1160 
1161 	if (rename(tmppath, path) != 0) {
1162 		err = got_error_from_errno3("rename", tmppath, path);
1163 		goto done;
1164 	}
1165 	free(tmppath);
1166 	tmppath = NULL;
1167 
1168 	if (chmod(path, sb.st_mode) != 0) {
1169 		err = got_error_from_errno2("chmod", path);
1170 		goto done;
1171 	}
1172 done:
1173 	if (ref->lf == NULL && lf)
1174 		unlock_err = got_lockfile_unlock(lf);
1175 	if (f) {
1176 		if (fclose(f) != 0 && err == NULL)
1177 			err = got_error_from_errno("fclose");
1178 	}
1179 	free(path_refs);
1180 	free(path);
1181 	if (tmppath) {
1182 		if (unlink(tmppath) != 0 && err == NULL)
1183 			err = got_error_from_errno2("unlink", tmppath);
1184 		free(tmppath);
1185 	}
1186 	return err ? err : unlock_err;
1187 }
1188 
1189 static const struct got_error *
1190 delete_packed_ref(struct got_reference *delref, struct got_repository *repo)
1191 {
1192 	const struct got_error *err = NULL, *unlock_err = NULL;
1193 	struct got_lockfile *lf = NULL;
1194 	FILE *f = NULL, *tmpf = NULL;
1195 	char *packed_refs_path, *tmppath = NULL;
1196 	struct got_reflist_head refs;
1197 	int found_delref = 0;
1198 
1199 	/* The packed-refs file does not cotain symbolic references. */
1200 	if (delref->flags & GOT_REF_IS_SYMBOLIC)
1201 		return got_error(GOT_ERR_BAD_REF_DATA);
1202 
1203 	SIMPLEQ_INIT(&refs);
1204 
1205 	packed_refs_path = got_repo_get_path_packed_refs(repo);
1206 	if (packed_refs_path == NULL)
1207 		return got_error_from_errno("got_repo_get_path_packed_refs");
1208 
1209 	err = got_opentemp_named(&tmppath, &tmpf, packed_refs_path);
1210 	if (err)
1211 		goto done;
1212 
1213 	if (delref->lf == NULL) {
1214 		err = got_lockfile_lock(&lf, packed_refs_path);
1215 		if (err)
1216 			goto done;
1217 	}
1218 
1219 	f = fopen(packed_refs_path, "r");
1220 	if (f == NULL) {
1221 		err = got_error_from_errno2("fopen", packed_refs_path);
1222 		goto done;
1223 	}
1224 	for (;;) {
1225 		char *line;
1226 		size_t len;
1227 		const char delim[3] = {'\0', '\0', '\0'};
1228 		struct got_reference *ref;
1229 		struct got_reflist_entry *new;
1230 
1231 		line = fparseln(f, &len, NULL, delim, 0);
1232 		if (line == NULL) {
1233 			if (feof(f))
1234 				break;
1235 			err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
1236 			goto done;
1237 		}
1238 		err = parse_packed_ref_line(&ref, NULL, line);
1239 		free(line);
1240 		if (err)
1241 			goto done;
1242 		if (ref == NULL)
1243 			continue;
1244 
1245 		if (strcmp(ref->ref.ref.name, delref->ref.ref.name) == 0 &&
1246 		    memcmp(ref->ref.ref.sha1, delref->ref.ref.sha1,
1247 		    sizeof(delref->ref.ref.sha1)) == 0) {
1248 			found_delref = 1;
1249 			got_ref_close(ref);
1250 			continue;
1251 		}
1252 
1253 		err = insert_ref(&new, &refs, ref, repo,
1254 		    got_ref_cmp_by_name, NULL);
1255 		if (err || new == NULL /* duplicate */)
1256 			got_ref_close(ref);
1257 		if (err)
1258 			goto done;
1259 	}
1260 
1261 	if (found_delref) {
1262 		struct got_reflist_entry *re;
1263 		size_t n;
1264 		struct stat sb;
1265 
1266 		n = fprintf(tmpf, "%s\n", GOT_PACKED_REFS_HEADER);
1267 		if (n != sizeof(GOT_PACKED_REFS_HEADER)) {
1268 			err = got_ferror(f, GOT_ERR_IO);
1269 			goto done;
1270 		}
1271 
1272 		SIMPLEQ_FOREACH(re, &refs, entry) {
1273 			uint8_t hex[SHA1_DIGEST_STRING_LENGTH];
1274 
1275 			if (got_sha1_digest_to_str(re->ref->ref.ref.sha1, hex,
1276 			    sizeof(hex)) == NULL) {
1277 				err = got_error(GOT_ERR_BAD_REF_DATA);
1278 				goto done;
1279 			}
1280 			n = fprintf(tmpf, "%s ", hex);
1281 			if (n != sizeof(hex)) {
1282 				err = got_ferror(f, GOT_ERR_IO);
1283 				goto done;
1284 			}
1285 			n = fprintf(tmpf, "%s\n", re->ref->ref.ref.name);
1286 			if (n != strlen(re->ref->ref.ref.name) + 1) {
1287 				err = got_ferror(f, GOT_ERR_IO);
1288 				goto done;
1289 			}
1290 		}
1291 
1292 		if (fflush(tmpf) != 0) {
1293 			err = got_error_from_errno("fflush");
1294 			goto done;
1295 		}
1296 
1297 		if (stat(packed_refs_path, &sb) != 0) {
1298 			if (errno != ENOENT) {
1299 				err = got_error_from_errno2("stat",
1300 				    packed_refs_path);
1301 				goto done;
1302 			}
1303 			sb.st_mode = GOT_DEFAULT_FILE_MODE;
1304 		}
1305 
1306 		if (rename(tmppath, packed_refs_path) != 0) {
1307 			err = got_error_from_errno3("rename", tmppath,
1308 			    packed_refs_path);
1309 			goto done;
1310 		}
1311 
1312 		if (chmod(packed_refs_path, sb.st_mode) != 0) {
1313 			err = got_error_from_errno2("chmod",
1314 			    packed_refs_path);
1315 			goto done;
1316 		}
1317 	}
1318 done:
1319 	if (delref->lf == NULL && lf)
1320 		unlock_err = got_lockfile_unlock(lf);
1321 	if (f) {
1322 		if (fclose(f) != 0 && err == NULL)
1323 			err = got_error_from_errno("fclose");
1324 	}
1325 	if (tmpf) {
1326 		unlink(tmppath);
1327 		if (fclose(tmpf) != 0 && err == NULL)
1328 			err = got_error_from_errno("fclose");
1329 	}
1330 	free(tmppath);
1331 	free(packed_refs_path);
1332 	got_ref_list_free(&refs);
1333 	return err ? err : unlock_err;
1334 }
1335 
1336 const struct got_error *
1337 got_ref_delete(struct got_reference *ref, struct got_repository *repo)
1338 {
1339 	const struct got_error *err = NULL, *unlock_err = NULL;
1340 	const char *name = got_ref_get_name(ref);
1341 	char *path_refs = NULL, *path = NULL;
1342 	struct got_lockfile *lf = NULL;
1343 
1344 	if (ref->flags & GOT_REF_IS_PACKED)
1345 		return delete_packed_ref(ref, repo);
1346 
1347 	path_refs = get_refs_dir_path(repo, name);
1348 	if (path_refs == NULL) {
1349 		err = got_error_from_errno2("get_refs_dir_path", name);
1350 		goto done;
1351 	}
1352 
1353 	if (asprintf(&path, "%s/%s", path_refs, name) == -1) {
1354 		err = got_error_from_errno("asprintf");
1355 		goto done;
1356 	}
1357 
1358 	if (ref->lf == NULL) {
1359 		err = got_lockfile_lock(&lf, path);
1360 		if (err)
1361 			goto done;
1362 	}
1363 
1364 	/* XXX: check if old content matches our expectations? */
1365 
1366 	if (unlink(path) != 0)
1367 		err = got_error_from_errno2("unlink", path);
1368 done:
1369 	if (ref->lf == NULL && lf)
1370 		unlock_err = got_lockfile_unlock(lf);
1371 
1372 	free(path_refs);
1373 	free(path);
1374 	return err ? err : unlock_err;
1375 }
1376 
1377 const struct got_error *
1378 got_ref_unlock(struct got_reference *ref)
1379 {
1380 	const struct got_error *err;
1381 	err = got_lockfile_unlock(ref->lf);
1382 	ref->lf = NULL;
1383 	return err;
1384 }