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Date:: Fri Feb 21 01:06:03 2020 UTC
Message:: allow 'got ref' to manipulate refs which do not have a slash in their name
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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 <util.h>
30 #include <zlib.h>
31 #include <time.h>
32 #include <libgen.h>
33 
34 #include "got_error.h"
35 #include "got_object.h"
36 #include "got_repository.h"
37 #include "got_reference.h"
38 #include "got_opentemp.h"
39 #include "got_path.h"
40 
41 #include "got_lib_sha1.h"
42 #include "got_lib_delta.h"
43 #include "got_lib_inflate.h"
44 #include "got_lib_object.h"
45 #include "got_lib_lockfile.h"
46 
47 #ifndef nitems
48 #define nitems(_a) (sizeof(_a) / sizeof((_a)[0]))
49 #endif
50 
51 #define GOT_REF_HEADS	"heads"
52 #define GOT_REF_TAGS	"tags"
53 #define GOT_REF_REMOTES	"remotes"
54 
55 /*
56  * We do not resolve tags yet, and don't yet care about sorting refs either,
57  * so packed-refs files we write contain a minimal header which disables all
58  * packed-refs "traits" supported by Git.
59  */
60 #define GOT_PACKED_REFS_HEADER	"# pack-refs with:"
61 
62 /* A symbolic reference. */
63 struct got_symref {
64 	char *name;
65 	char *ref;
66 };
67 
68 #define GOT_REF_RECURSE_MAX	20
69 
70 /* A non-symbolic reference (there is no better designation). */
71 struct got_ref {
72 	char *name;
73 	u_int8_t sha1[SHA1_DIGEST_LENGTH];
74 };
75 
76 /* A reference which points to an arbitrary object. */
77 struct got_reference {
78 	unsigned int flags;
79 #define GOT_REF_IS_SYMBOLIC	0x01
80 #define GOT_REF_IS_PACKED	0x02
81 
82 	union {
83 		struct got_ref ref;
84 		struct got_symref symref;
85 	} ref;
86 
87 	struct got_lockfile *lf;
88 };
89 
90 static const struct got_error *
91 alloc_ref(struct got_reference **ref, const char *name,
92     struct got_object_id *id, int flags)
93 {
94 	const struct got_error *err = NULL;
95 
96 	*ref = calloc(1, sizeof(**ref));
97 	if (*ref == NULL)
98 		return got_error_from_errno("calloc");
99 
100 	memcpy((*ref)->ref.ref.sha1, id->sha1, sizeof((*ref)->ref.ref.sha1));
101 	(*ref)->flags = flags;
102 	(*ref)->ref.ref.name = strdup(name);
103 	if ((*ref)->ref.ref.name == NULL) {
104 		err = got_error_from_errno("strdup");
105 		got_ref_close(*ref);
106 		*ref = NULL;
107 	}
108 	return err;
109 }
110 
111 static const struct got_error *
112 alloc_symref(struct got_reference **ref, const char *name,
113     const char *target_ref, int flags)
114 {
115 	const struct got_error *err = NULL;
116 
117 	*ref = calloc(1, sizeof(**ref));
118 	if (*ref == NULL)
119 		return got_error_from_errno("calloc");
120 
121 	(*ref)->flags = GOT_REF_IS_SYMBOLIC | flags;
122 	(*ref)->ref.symref.name = strdup(name);
123 	if ((*ref)->ref.symref.name == NULL) {
124 		err = got_error_from_errno("strdup");
125 		got_ref_close(*ref);
126 		*ref = NULL;
127 		return err;
128 	}
129 	(*ref)->ref.symref.ref = strdup(target_ref);
130 	if ((*ref)->ref.symref.ref == NULL) {
131 		err = got_error_from_errno("strdup");
132 		got_ref_close(*ref);
133 		*ref = NULL;
134 	}
135 	return err;
136 }
137 
138 static const struct got_error *
139 parse_symref(struct got_reference **ref, const char *name, const char *line)
140 {
141 	if (line[0] == '\0')
142 		return got_error(GOT_ERR_BAD_REF_DATA);
143 
144 	return alloc_symref(ref, name, line, 0);
145 }
146 
147 static const struct got_error *
148 parse_ref_line(struct got_reference **ref, const char *name, const char *line)
149 {
150 	struct got_object_id id;
151 
152 	if (strncmp(line, "ref: ", 5) == 0) {
153 		line += 5;
154 		return parse_symref(ref, name, line);
155 	}
156 
157 	if (!got_parse_sha1_digest(id.sha1, line))
158 		return got_error(GOT_ERR_BAD_REF_DATA);
159 
160 	return alloc_ref(ref, name, &id, 0);
161 }
162 
163 static const struct got_error *
164 parse_ref_file(struct got_reference **ref, const char *name,
165     const char *abspath, int lock)
166 {
167 	const struct got_error *err = NULL;
168 	FILE *f;
169 	char *line = NULL;
170 	size_t linesize = 0;
171 	ssize_t linelen;
172 	struct got_lockfile *lf = NULL;
173 
174 	if (lock) {
175 		err = got_lockfile_lock(&lf, abspath);
176 		if (err)
177 			return (err);
178 	}
179 
180 	f = fopen(abspath, "rb");
181 	if (f == NULL) {
182 		if (lock)
183 			got_lockfile_unlock(lf);
184 		return NULL;
185 	}
186 
187 	linelen = getline(&line, &linesize, f);
188 	if (linelen == -1) {
189 		if (feof(f))
190 			err = NULL; /* ignore empty files (could be locks) */
191 		else
192 			err = got_error_from_errno2("getline", abspath);
193 		if (lock)
194 			got_lockfile_unlock(lf);
195 		goto done;
196 	}
197 	while (linelen > 0 && line[linelen - 1] == '\n') {
198 		line[linelen - 1] = '\0';
199 		linelen--;
200 	}
201 
202 	err = parse_ref_line(ref, name, line);
203 	if (lock) {
204 		if (err)
205 			got_lockfile_unlock(lf);
206 		else {
207 			if (*ref)
208 				(*ref)->lf = lf;
209 			else
210 				got_lockfile_unlock(lf);
211 		}
212 	}
213 done:
214 	free(line);
215 	if (fclose(f) != 0 && err == NULL) {
216 		err = got_error_from_errno("fclose");
217 		if (*ref) {
218 			if (lock)
219 				got_ref_unlock(*ref);
220 			got_ref_close(*ref);
221 			*ref = NULL;
222 		}
223 	}
224 	return err;
225 }
226 
227 static int
228 is_well_known_ref(const char *refname)
229 {
230 	return (strcmp(refname, GOT_REF_HEAD) == 0 ||
231 	    strcmp(refname, GOT_REF_ORIG_HEAD) == 0 ||
232 	    strcmp(refname, GOT_REF_MERGE_HEAD) == 0 ||
233 	    strcmp(refname, GOT_REF_FETCH_HEAD) == 0);
234 }
235 
236 static char *
237 get_refs_dir_path(struct got_repository *repo, const char *refname)
238 {
239 	if (is_well_known_ref(refname) || strncmp(refname, "refs/", 5) == 0)
240 		return strdup(got_repo_get_path_git_dir(repo));
241 
242 	return got_repo_get_path_refs(repo);
243 }
244 
245 static int
246 is_valid_ref_name(const char *name)
247 {
248 	const char *s, *seg;
249 	const char forbidden[] = { ' ', '~', '^', ':', '?', '*', '[' , '\\' };
250 	const char *forbidden_seq[] = { "//", "..", "@{" };
251 	const char *lfs = GOT_LOCKFILE_SUFFIX;
252 	const size_t lfs_len = sizeof(GOT_LOCKFILE_SUFFIX) - 1;
253 	int i;
254 
255 	if (name[0] == '@' && name[1] == '\0')
256 		return 0;
257 
258 	s = name;
259 	seg = s;
260 	if (seg[0] == '\0' || seg[0] == '.' || seg[0] == '/')
261 		return 0;
262 	while (*s) {
263 		for (i = 0; i < nitems(forbidden); i++) {
264 			if (*s == forbidden[i])
265 				return 0;
266 		}
267 		for (i = 0; i < nitems(forbidden_seq); i++) {
268 			if (s[0] == forbidden_seq[i][0] &&
269 			    s[1] == forbidden_seq[i][1])
270 				return 0;
271 		}
272 		if (iscntrl((unsigned char)s[0]))
273 			return 0;
274 		if (s[0] == '.' && s[1] == '\0')
275 			return 0;
276 		if (*s == '/') {
277 			const char *nextseg = s + 1;
278 			if (nextseg[0] == '\0' || nextseg[0] == '.' ||
279 			    nextseg[0] == '/')
280 				return 0;
281 			if (seg <= s - lfs_len &&
282 			    strncmp(s - lfs_len, lfs, lfs_len) == 0)
283 				return 0;
284 			seg = nextseg;
285 		}
286 		s++;
287 	}
288 
289 	if (seg <= s - lfs_len &&
290 	    strncmp(s - lfs_len, lfs, lfs_len) == 0)
291 		return 0;
292 
293 	return 1;
294 }
295 
296 const struct got_error *
297 got_ref_alloc(struct got_reference **ref, const char *name,
298     struct got_object_id *id)
299 {
300 	if (!is_valid_ref_name(name))
301 		return got_error_path(name, GOT_ERR_BAD_REF_NAME);
302 
303 	return alloc_ref(ref, name, id, 0);
304 }
305 
306 const struct got_error *
307 got_ref_alloc_symref(struct got_reference **ref, const char *name,
308 	struct got_reference *target_ref)
309 {
310 	if (!is_valid_ref_name(name))
311 		return got_error_path(name, GOT_ERR_BAD_REF_NAME);
312 
313 	return alloc_symref(ref, name, got_ref_get_name(target_ref), 0);
314 }
315 
316 static const struct got_error *
317 parse_packed_ref_line(struct got_reference **ref, const char *abs_refname,
318     const char *line)
319 {
320 	struct got_object_id id;
321 	const char *name;
322 
323 	*ref = NULL;
324 
325 	if (line[0] == '#' || line[0] == '^')
326 		return NULL;
327 
328 	if (!got_parse_sha1_digest(id.sha1, line))
329 		return got_error(GOT_ERR_BAD_REF_DATA);
330 
331 	if (abs_refname) {
332 		if (strcmp(line + SHA1_DIGEST_STRING_LENGTH, abs_refname) != 0)
333 			return NULL;
334 		name = abs_refname;
335 	} else
336 		name = line + SHA1_DIGEST_STRING_LENGTH;
337 
338 	return alloc_ref(ref, name, &id, GOT_REF_IS_PACKED);
339 }
340 
341 static const struct got_error *
342 open_packed_ref(struct got_reference **ref, FILE *f, const char **subdirs,
343     int nsubdirs, const char *refname)
344 {
345 	const struct got_error *err = NULL;
346 	char *abs_refname;
347 	char *line;
348 	size_t len;
349 	const char delim[3] = {'\0', '\0', '\0'};
350 	int i, ref_is_absolute = (strncmp(refname, "refs/", 5) == 0);
351 
352 	*ref = NULL;
353 
354 	if (ref_is_absolute)
355 		abs_refname = (char *)refname;
356 	do {
357 		line = fparseln(f, &len, NULL, delim, 0);
358 		if (line == NULL) {
359 			if (feof(f))
360 				break;
361 			err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
362 			break;
363 		}
364 		for (i = 0; i < nsubdirs; i++) {
365 			if (!ref_is_absolute &&
366 			    asprintf(&abs_refname, "refs/%s/%s", subdirs[i],
367 			    refname) == -1)
368 				return got_error_from_errno("asprintf");
369 			err = parse_packed_ref_line(ref, abs_refname, line);
370 			if (!ref_is_absolute)
371 				free(abs_refname);
372 			if (err || *ref != NULL)
373 				break;
374 		}
375 		free(line);
376 		if (err)
377 			break;
378 	} while (*ref == NULL);
379 
380 	return err;
381 }
382 
383 static const struct got_error *
384 open_ref(struct got_reference **ref, const char *path_refs, const char *subdir,
385     const char *name, int lock)
386 {
387 	const struct got_error *err = NULL;
388 	char *path = NULL;
389 	char *absname = NULL;
390 	int ref_is_absolute = (strncmp(name, "refs/", 5) == 0);
391 	int ref_is_well_known = is_well_known_ref(name);
392 
393 	*ref = NULL;
394 
395 	if (ref_is_absolute || ref_is_well_known) {
396 		if (asprintf(&path, "%s/%s", path_refs, name) == -1)
397 			return got_error_from_errno("asprintf");
398 		absname = (char *)name;
399 	} else {
400 		if (asprintf(&path, "%s/%s%s%s", path_refs, subdir,
401 		    subdir[0] ? "/" : "", name) == -1)
402 			return got_error_from_errno("asprintf");
403 
404 		if (asprintf(&absname, "refs/%s%s%s",
405 		    subdir, subdir[0] ? "/" : "", name) == -1) {
406 			err = got_error_from_errno("asprintf");
407 			goto done;
408 		}
409 	}
410 
411 	err = parse_ref_file(ref, absname, path, lock);
412 done:
413 	if (!ref_is_absolute && !ref_is_well_known)
414 		free(absname);
415 	free(path);
416 	return err;
417 }
418 
419 const struct got_error *
420 got_ref_open(struct got_reference **ref, struct got_repository *repo,
421    const char *refname, int lock)
422 {
423 	const struct got_error *err = NULL;
424 	char *path_refs = NULL;
425 	const char *subdirs[] = {
426 	    GOT_REF_HEADS, GOT_REF_TAGS, GOT_REF_REMOTES
427 	};
428 	int i, well_known = is_well_known_ref(refname);
429 	struct got_lockfile *lf = NULL;
430 
431 	*ref = NULL;
432 
433 	path_refs = get_refs_dir_path(repo, refname);
434 	if (path_refs == NULL) {
435 		err = got_error_from_errno2("get_refs_dir_path", refname);
436 		goto done;
437 	}
438 
439 	if (well_known) {
440 		err = open_ref(ref, path_refs, "", refname, lock);
441 	} else {
442 		char *packed_refs_path;
443 		FILE *f;
444 
445 		/* Search on-disk refs before packed refs! */
446 		for (i = 0; i < nitems(subdirs); i++) {
447 			err = open_ref(ref, path_refs, subdirs[i], refname,
448 			    lock);
449 			if (err || *ref)
450 				goto done;
451 		}
452 
453 		packed_refs_path = got_repo_get_path_packed_refs(repo);
454 		if (packed_refs_path == NULL) {
455 			err = got_error_from_errno(
456 			    "got_repo_get_path_packed_refs");
457 			goto done;
458 		}
459 
460 		if (lock) {
461 			err = got_lockfile_lock(&lf, packed_refs_path);
462 			if (err)
463 				goto done;
464 		}
465 		f = fopen(packed_refs_path, "rb");
466 		free(packed_refs_path);
467 		if (f != NULL) {
468 			err = open_packed_ref(ref, f, subdirs, nitems(subdirs),
469 			    refname);
470 			if (!err) {
471 				if (fclose(f) != 0) {
472 					err = got_error_from_errno("fclose");
473 					got_ref_close(*ref);
474 					*ref = NULL;
475 				} else if (*ref)
476 					(*ref)->lf = lf;
477 			}
478 		}
479 	}
480 done:
481 	if (!err && *ref == NULL)
482 		err = got_error_not_ref(refname);
483 	if (err && lf)
484 		got_lockfile_unlock(lf);
485 	free(path_refs);
486 	return err;
487 }
488 
489 void
490 got_ref_close(struct got_reference *ref)
491 {
492 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
493 		free(ref->ref.symref.name);
494 		free(ref->ref.symref.ref);
495 	} else
496 		free(ref->ref.ref.name);
497 	free(ref);
498 }
499 
500 struct got_reference *
501 got_ref_dup(struct got_reference *ref)
502 {
503 	struct got_reference *ret;
504 
505 	ret = calloc(1, sizeof(*ret));
506 	if (ret == NULL)
507 		return NULL;
508 
509 	ret->flags = ref->flags;
510 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
511 		ret->ref.symref.name = strdup(ref->ref.symref.name);
512 		if (ret->ref.symref.name == NULL) {
513 			free(ret);
514 			return NULL;
515 		}
516 		ret->ref.symref.ref = strdup(ref->ref.symref.ref);
517 		if (ret->ref.symref.ref == NULL) {
518 			free(ret->ref.symref.name);
519 			free(ret);
520 			return NULL;
521 		}
522 	} else {
523 		ref->ref.ref.name = strdup(ref->ref.ref.name);
524 		if (ref->ref.ref.name == NULL) {
525 			free(ret);
526 			return NULL;
527 		}
528 		memcpy(ret->ref.ref.sha1, ref->ref.ref.sha1,
529 		    sizeof(ret->ref.ref.sha1));
530 	}
531 
532 	return ret;
533 }
534 
535 const struct got_error *
536 got_reflist_entry_dup(struct got_reflist_entry **newp,
537     struct got_reflist_entry *re)
538 {
539 	const struct got_error *err = NULL;
540 	struct got_reflist_entry *new;
541 
542 	*newp = NULL;
543 
544 	new = malloc(sizeof(*new));
545 	if (new == NULL)
546 		return got_error_from_errno("malloc");
547 
548 	new->ref = got_ref_dup(re->ref);
549 	if (new->ref == NULL) {
550 		err = got_error_from_errno("got_ref_dup");
551 		free(new);
552 		return err;
553 	}
554 
555 	new->id = got_object_id_dup(re->id);
556 	if (new->id == NULL) {
557 		err = got_error_from_errno("got_ref_dup");
558 		free(new->id);
559 		free(new);
560 		return err;
561 	}
562 
563 	*newp = new;
564 	return NULL;
565 }
566 
567 static const struct got_error *
568 resolve_symbolic_ref(struct got_reference **resolved,
569     struct got_repository *repo, struct got_reference *ref)
570 {
571 	struct got_reference *nextref;
572 	const struct got_error *err;
573 
574 	err = got_ref_open(&nextref, repo, ref->ref.symref.ref, 0);
575 	if (err)
576 		return err;
577 
578 	if (nextref->flags & GOT_REF_IS_SYMBOLIC)
579 		err = resolve_symbolic_ref(resolved, repo, nextref);
580 	else
581 		*resolved = got_ref_dup(nextref);
582 
583 	got_ref_close(nextref);
584 	return err;
585 }
586 
587 static const struct got_error *
588 ref_resolve(struct got_object_id **id, struct got_repository *repo,
589     struct got_reference *ref, int recursion)
590 {
591 	const struct got_error *err;
592 
593 	if (recursion <= 0)
594 		return got_error_msg(GOT_ERR_RECURSION,
595 		    "reference recursion limit reached");
596 
597 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
598 		struct got_reference *resolved = NULL;
599 		err = resolve_symbolic_ref(&resolved, repo, ref);
600 		if (err == NULL)
601 			err = ref_resolve(id, repo, resolved, --recursion);
602 		if (resolved)
603 			got_ref_close(resolved);
604 		return err;
605 	}
606 
607 	*id = calloc(1, sizeof(**id));
608 	if (*id == NULL)
609 		return got_error_from_errno("calloc");
610 	memcpy((*id)->sha1, ref->ref.ref.sha1, sizeof((*id)->sha1));
611 	return NULL;
612 }
613 
614 const struct got_error *
615 got_ref_resolve(struct got_object_id **id, struct got_repository *repo,
616     struct got_reference *ref)
617 {
618 	return ref_resolve(id, repo, ref, GOT_REF_RECURSE_MAX);
619 }
620 
621 char *
622 got_ref_to_str(struct got_reference *ref)
623 {
624 	char *str;
625 
626 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
627 		return strdup(ref->ref.symref.ref);
628 
629 	str = malloc(SHA1_DIGEST_STRING_LENGTH);
630 	if (str == NULL)
631 		return NULL;
632 
633 	if (got_sha1_digest_to_str(ref->ref.ref.sha1, str,
634 	    SHA1_DIGEST_STRING_LENGTH) == NULL) {
635 		free(str);
636 		return NULL;
637 	}
638 
639 	return str;
640 }
641 
642 const char *
643 got_ref_get_name(struct got_reference *ref)
644 {
645 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
646 		return ref->ref.symref.name;
647 
648 	return ref->ref.ref.name;
649 }
650 
651 const char *
652 got_ref_get_symref_target(struct got_reference *ref)
653 {
654 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
655 		return ref->ref.symref.ref;
656 
657 	return NULL;
658 }
659 
660 const struct got_error *
661 got_ref_cmp_by_name(void *arg, int *cmp, struct got_reference *re1,
662     struct got_reference* re2)
663 {
664 	const char *name1 = got_ref_get_name(re1);
665 	const char *name2 = got_ref_get_name(re2);
666 
667 	*cmp = got_path_cmp(name1, name2, strlen(name1), strlen(name2));
668 	return NULL;
669 }
670 
671 const struct got_error *
672 got_ref_cmp_tags(void *arg, int *cmp, struct got_reference *ref1,
673     struct got_reference *ref2)
674 {
675 	const struct got_error *err = NULL;
676 	struct got_repository *repo = arg;
677 	struct got_object_id *id1, *id2 = NULL;
678 	struct got_tag_object *tag1 = NULL, *tag2 = NULL;
679 	struct got_commit_object *commit1 = NULL, *commit2 = NULL;
680 	time_t time1, time2;
681 
682 	*cmp = 0;
683 
684 	err = got_ref_resolve(&id1, repo, ref1);
685 	if (err)
686 		return err;
687 	err = got_object_open_as_tag(&tag1, repo, id1);
688 	if (err) {
689 		if (err->code != GOT_ERR_OBJ_TYPE)
690 			goto done;
691 		/* "lightweight" tag */
692 		err = got_object_open_as_commit(&commit1, repo, id1);
693 		if (err)
694 			goto done;
695 		time1 = got_object_commit_get_committer_time(commit1);
696 	} else
697 		time1 = got_object_tag_get_tagger_time(tag1);
698 
699 	err = got_ref_resolve(&id2, repo, ref2);
700 	if (err)
701 		goto done;
702 	err = got_object_open_as_tag(&tag2, repo, id2);
703 	if (err) {
704 		if (err->code != GOT_ERR_OBJ_TYPE)
705 			goto done;
706 		/* "lightweight" tag */
707 		err = got_object_open_as_commit(&commit2, repo, id2);
708 		if (err)
709 			goto done;
710 		time2 = got_object_commit_get_committer_time(commit2);
711 	} else
712 		time2 = got_object_tag_get_tagger_time(tag2);
713 
714 	/* Put latest tags first. */
715 	if (time1 < time2)
716 		*cmp = 1;
717 	else if (time1 > time2)
718 		*cmp = -1;
719 	else
720 		err = got_ref_cmp_by_name(NULL, cmp, ref2, ref1);
721 done:
722 	free(id1);
723 	free(id2);
724 	if (tag1)
725 		got_object_tag_close(tag1);
726 	if (tag2)
727 		got_object_tag_close(tag2);
728 	if (commit1)
729 		got_object_commit_close(commit1);
730 	if (commit2)
731 		got_object_commit_close(commit2);
732 	return err;
733 }
734 
735 static const struct got_error *
736 insert_ref(struct got_reflist_entry **newp, struct got_reflist_head *refs,
737     struct got_reference *ref, struct got_repository *repo,
738     got_ref_cmp_cb cmp_cb, void *cmp_arg)
739 {
740 	const struct got_error *err;
741 	struct got_object_id *id;
742 	struct got_reflist_entry *new, *re, *prev = NULL;
743 	int cmp;
744 
745 	*newp = NULL;
746 
747 	err = got_ref_resolve(&id, repo, ref);
748 	if (err)
749 		return err;
750 
751 	new = malloc(sizeof(*new));
752 	if (new == NULL) {
753 		free(id);
754 		return got_error_from_errno("malloc");
755 	}
756 	new->ref = ref;
757 	new->id = id;
758 	*newp = new;
759 
760 	/*
761 	 * We must de-duplicate entries on insert because packed-refs may
762 	 * contain redundant entries. On-disk refs take precedence.
763 	 * This code assumes that on-disk revs are read before packed-refs.
764 	 * We're iterating the list anyway, so insert elements sorted by name.
765 	 */
766 	re = SIMPLEQ_FIRST(refs);
767 	while (re) {
768 		err = (*cmp_cb)(cmp_arg, &cmp, re->ref, new->ref);
769 		if (err)
770 			return err;
771 		if (cmp == 0) {
772 			/* duplicate */
773 			free(new->id);
774 			free(new);
775 			*newp = NULL;
776 			return NULL;
777 		} else if (cmp > 0) {
778 			if (prev)
779 				SIMPLEQ_INSERT_AFTER(refs, prev, new, entry);
780 			else
781 				SIMPLEQ_INSERT_HEAD(refs, new, entry);
782 			return NULL;
783 		} else {
784 			prev = re;
785 			re = SIMPLEQ_NEXT(re, entry);
786 		}
787 	}
788 
789 	SIMPLEQ_INSERT_TAIL(refs, new, entry);
790 	return NULL;
791 }
792 
793 static const struct got_error *
794 gather_on_disk_refs(struct got_reflist_head *refs, const char *path_refs,
795     const char *subdir, struct got_repository *repo,
796     got_ref_cmp_cb cmp_cb, void *cmp_arg)
797 {
798 	const struct got_error *err = NULL;
799 	DIR *d = NULL;
800 	char *path_subdir;
801 
802 	if (asprintf(&path_subdir, "%s/%s", path_refs, subdir) == -1)
803 		return got_error_from_errno("asprintf");
804 
805 	d = opendir(path_subdir);
806 	if (d == NULL)
807 		goto done;
808 
809 	for (;;) {
810 		struct dirent *dent;
811 		struct got_reference *ref;
812 		char *child;
813 
814 		dent = readdir(d);
815 		if (dent == NULL)
816 			break;
817 
818 		if (strcmp(dent->d_name, ".") == 0 ||
819 		    strcmp(dent->d_name, "..") == 0)
820 			continue;
821 
822 		switch (dent->d_type) {
823 		case DT_REG:
824 			err = open_ref(&ref, path_refs, subdir, dent->d_name,
825 			    0);
826 			if (err)
827 				goto done;
828 			if (ref) {
829 				struct got_reflist_entry *new;
830 				err = insert_ref(&new, refs, ref, repo,
831 				    cmp_cb, cmp_arg);
832 				if (err || new == NULL /* duplicate */)
833 					got_ref_close(ref);
834 				if (err)
835 					goto done;
836 			}
837 			break;
838 		case DT_DIR:
839 			if (asprintf(&child, "%s%s%s", subdir,
840 			    subdir[0] == '\0' ? "" : "/", dent->d_name) == -1) {
841 				err = got_error_from_errno("asprintf");
842 				break;
843 			}
844 			err = gather_on_disk_refs(refs, path_refs, child, repo,
845 			    cmp_cb, cmp_arg);
846 			free(child);
847 			break;
848 		default:
849 			break;
850 		}
851 	}
852 done:
853 	if (d)
854 		closedir(d);
855 	free(path_subdir);
856 	return err;
857 }
858 
859 const struct got_error *
860 got_ref_list(struct got_reflist_head *refs, struct got_repository *repo,
861     const char *ref_namespace, got_ref_cmp_cb cmp_cb, void *cmp_arg)
862 {
863 	const struct got_error *err;
864 	char *packed_refs_path, *path_refs = NULL;
865 	const char *ondisk_ref_namespace = NULL;
866 	FILE *f = NULL;
867 	struct got_reference *ref;
868 	struct got_reflist_entry *new;
869 
870 	if (ref_namespace == NULL || ref_namespace[0] == '\0') {
871 		/* HEAD ref should always exist. */
872 		path_refs = get_refs_dir_path(repo, GOT_REF_HEAD);
873 		if (path_refs == NULL) {
874 			err = got_error_from_errno("get_refs_dir_path");
875 			goto done;
876 		}
877 		err = open_ref(&ref, path_refs, "", GOT_REF_HEAD, 0);
878 		if (err)
879 			goto done;
880 		err = insert_ref(&new, refs, ref, repo, cmp_cb, cmp_arg);
881 		if (err || new == NULL /* duplicate */)
882 			got_ref_close(ref);
883 		if (err)
884 			goto done;
885 	}
886 
887 	ondisk_ref_namespace = ref_namespace;
888 	if (ref_namespace && strncmp(ref_namespace, "refs/", 5) == 0)
889 		ondisk_ref_namespace += 5;
890 
891 	/* Gather on-disk refs before parsing packed-refs. */
892 	free(path_refs);
893 	path_refs = get_refs_dir_path(repo, "");
894 	if (path_refs == NULL) {
895 		err = got_error_from_errno("get_refs_dir_path");
896 		goto done;
897 	}
898 	err = gather_on_disk_refs(refs, path_refs,
899 	    ondisk_ref_namespace ? ondisk_ref_namespace : "", repo,
900 	    cmp_cb, cmp_arg);
901 	if (err)
902 		goto done;
903 
904 	/*
905 	 * The packed-refs file may contain redundant entries, in which
906 	 * case on-disk refs take precedence.
907 	 */
908 	packed_refs_path = got_repo_get_path_packed_refs(repo);
909 	if (packed_refs_path == NULL) {
910 		err = got_error_from_errno("got_repo_get_path_packed_refs");
911 		goto done;
912 	}
913 
914 	f = fopen(packed_refs_path, "r");
915 	free(packed_refs_path);
916 	if (f) {
917 		char *line;
918 		size_t len;
919 		const char delim[3] = {'\0', '\0', '\0'};
920 		for (;;) {
921 			line = fparseln(f, &len, NULL, delim, 0);
922 			if (line == NULL) {
923 				if (feof(f))
924 					break;
925 				err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
926 				goto done;
927 			}
928 			err = parse_packed_ref_line(&ref, NULL, line);
929 			free(line);
930 			if (err)
931 				goto done;
932 			if (ref) {
933 				if (ref_namespace) {
934 					const char *name;
935 					name = got_ref_get_name(ref);
936 					if (strncmp(name, ref_namespace,
937 					    strlen(ref_namespace)) != 0) {
938 						got_ref_close(ref);
939 						continue;
940 					}
941 				}
942 				err = insert_ref(&new, refs, ref, repo,
943 				    cmp_cb, cmp_arg);
944 				if (err || new == NULL /* duplicate */)
945 					got_ref_close(ref);
946 				if (err)
947 					goto done;
948 			}
949 		}
950 	}
951 done:
952 	free(path_refs);
953 	if (f && fclose(f) != 0 && err == NULL)
954 		err = got_error_from_errno("fclose");
955 	return err;
956 }
957 
958 void
959 got_ref_list_free(struct got_reflist_head *refs)
960 {
961 	struct got_reflist_entry *re;
962 
963 	while (!SIMPLEQ_EMPTY(refs)) {
964 		re = SIMPLEQ_FIRST(refs);
965 		SIMPLEQ_REMOVE_HEAD(refs, entry);
966 		got_ref_close(re->ref);
967 		free(re->id);
968 		free(re);
969 	}
970 
971 }
972 
973 int
974 got_ref_is_symbolic(struct got_reference *ref)
975 {
976 	return (ref->flags & GOT_REF_IS_SYMBOLIC);
977 }
978 
979 const struct got_error *
980 got_ref_change_ref(struct got_reference *ref, struct got_object_id *id)
981 {
982 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
983 		return got_error(GOT_ERR_BAD_REF_TYPE);
984 
985 	memcpy(ref->ref.ref.sha1, id->sha1, sizeof(ref->ref.ref.sha1));
986 	return NULL;
987 }
988 
989 const struct got_error *
990 got_ref_change_symref(struct got_reference *ref, char *refname)
991 {
992 	char *new_name;
993 
994 	if ((ref->flags & GOT_REF_IS_SYMBOLIC) == 0)
995 		return got_error(GOT_ERR_BAD_REF_TYPE);
996 
997 	new_name = strdup(refname);
998 	if (new_name == NULL)
999 		return got_error_from_errno("strdup");
1000 
1001 	free(ref->ref.symref.name);
1002 	ref->ref.symref.name = new_name;
1003 	return NULL;
1004 }
1005 
1006 const struct got_error *
1007 got_ref_write(struct got_reference *ref, struct got_repository *repo)
1008 {
1009 	const struct got_error *err = NULL, *unlock_err = NULL;
1010 	const char *name = got_ref_get_name(ref);
1011 	char *path_refs = NULL, *path = NULL, *tmppath = NULL;
1012 	struct got_lockfile *lf = NULL;
1013 	FILE *f = NULL;
1014 	size_t n;
1015 	struct stat sb;
1016 
1017 	path_refs = get_refs_dir_path(repo, name);
1018 	if (path_refs == NULL) {
1019 		err = got_error_from_errno2("get_refs_dir_path", name);
1020 		goto done;
1021 	}
1022 
1023 	if (asprintf(&path, "%s/%s", path_refs, name) == -1) {
1024 		err = got_error_from_errno("asprintf");
1025 		goto done;
1026 	}
1027 
1028 	err = got_opentemp_named(&tmppath, &f, path);
1029 	if (err) {
1030 		char *parent;
1031 		if (!(err->code == GOT_ERR_ERRNO && errno == ENOENT))
1032 			goto done;
1033 		err = got_path_dirname(&parent, path);
1034 		if (err)
1035 			goto done;
1036 		err = got_path_mkdir(parent);
1037 		free(parent);
1038 		if (err)
1039 			goto done;
1040 		err = got_opentemp_named(&tmppath, &f, path);
1041 		if (err)
1042 			goto done;
1043 	}
1044 
1045 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
1046 		n = fprintf(f, "ref: %s\n", ref->ref.symref.ref);
1047 		if (n != strlen(ref->ref.symref.ref) + 6) {
1048 			err = got_ferror(f, GOT_ERR_IO);
1049 			goto done;
1050 		}
1051 	} else {
1052 		char hex[SHA1_DIGEST_STRING_LENGTH];
1053 		if (got_sha1_digest_to_str(ref->ref.ref.sha1, hex,
1054 		    sizeof(hex)) == NULL) {
1055 			err = got_error(GOT_ERR_BAD_REF_DATA);
1056 			goto done;
1057 		}
1058 		n = fprintf(f, "%s\n", hex);
1059 		if (n != sizeof(hex)) {
1060 			err = got_ferror(f, GOT_ERR_IO);
1061 			goto done;
1062 		}
1063 	}
1064 
1065 	if (ref->lf == NULL) {
1066 		err = got_lockfile_lock(&lf, path);
1067 		if (err)
1068 			goto done;
1069 	}
1070 
1071 	/* XXX: check if old content matches our expectations? */
1072 
1073 	if (stat(path, &sb) != 0) {
1074 		if (errno != ENOENT) {
1075 			err = got_error_from_errno2("stat", path);
1076 			goto done;
1077 		}
1078 		sb.st_mode = GOT_DEFAULT_FILE_MODE;
1079 	}
1080 
1081 	if (rename(tmppath, path) != 0) {
1082 		err = got_error_from_errno3("rename", tmppath, path);
1083 		goto done;
1084 	}
1085 	free(tmppath);
1086 	tmppath = NULL;
1087 
1088 	if (chmod(path, sb.st_mode) != 0) {
1089 		err = got_error_from_errno2("chmod", path);
1090 		goto done;
1091 	}
1092 done:
1093 	if (ref->lf == NULL && lf)
1094 		unlock_err = got_lockfile_unlock(lf);
1095 	if (f) {
1096 		if (fclose(f) != 0 && err == NULL)
1097 			err = got_error_from_errno("fclose");
1098 	}
1099 	free(path_refs);
1100 	free(path);
1101 	if (tmppath) {
1102 		if (unlink(tmppath) != 0 && err == NULL)
1103 			err = got_error_from_errno2("unlink", tmppath);
1104 		free(tmppath);
1105 	}
1106 	return err ? err : unlock_err;
1107 }
1108 
1109 static const struct got_error *
1110 delete_packed_ref(struct got_reference *delref, struct got_repository *repo)
1111 {
1112 	const struct got_error *err = NULL, *unlock_err = NULL;
1113 	struct got_lockfile *lf = NULL;
1114 	FILE *f = NULL, *tmpf = NULL;
1115 	char *packed_refs_path, *tmppath = NULL;
1116 	struct got_reflist_head refs;
1117 	int found_delref = 0;
1118 
1119 	/* The packed-refs file does not cotain symbolic references. */
1120 	if (delref->flags & GOT_REF_IS_SYMBOLIC)
1121 		return got_error(GOT_ERR_BAD_REF_DATA);
1122 
1123 	SIMPLEQ_INIT(&refs);
1124 
1125 	packed_refs_path = got_repo_get_path_packed_refs(repo);
1126 	if (packed_refs_path == NULL)
1127 		return got_error_from_errno("got_repo_get_path_packed_refs");
1128 
1129 	err = got_opentemp_named(&tmppath, &tmpf, packed_refs_path);
1130 	if (err)
1131 		goto done;
1132 
1133 	if (delref->lf == NULL) {
1134 		err = got_lockfile_lock(&lf, packed_refs_path);
1135 		if (err)
1136 			goto done;
1137 	}
1138 
1139 	f = fopen(packed_refs_path, "r");
1140 	if (f == NULL) {
1141 		err = got_error_from_errno2("fopen", packed_refs_path);
1142 		goto done;
1143 	}
1144 	for (;;) {
1145 		char *line;
1146 		size_t len;
1147 		const char delim[3] = {'\0', '\0', '\0'};
1148 		struct got_reference *ref;
1149 		struct got_reflist_entry *new;
1150 
1151 		line = fparseln(f, &len, NULL, delim, 0);
1152 		if (line == NULL) {
1153 			if (feof(f))
1154 				break;
1155 			err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
1156 			goto done;
1157 		}
1158 		err = parse_packed_ref_line(&ref, NULL, line);
1159 		free(line);
1160 		if (err)
1161 			goto done;
1162 		if (ref == NULL)
1163 			continue;
1164 
1165 		if (strcmp(ref->ref.ref.name, delref->ref.ref.name) == 0 &&
1166 		    memcmp(ref->ref.ref.sha1, delref->ref.ref.sha1,
1167 		    sizeof(delref->ref.ref.sha1)) == 0) {
1168 			found_delref = 1;
1169 			got_ref_close(ref);
1170 			continue;
1171 		}
1172 
1173 		err = insert_ref(&new, &refs, ref, repo,
1174 		    got_ref_cmp_by_name, NULL);
1175 		if (err || new == NULL /* duplicate */)
1176 			got_ref_close(ref);
1177 		if (err)
1178 			goto done;
1179 	}
1180 
1181 	if (found_delref) {
1182 		struct got_reflist_entry *re;
1183 		size_t n;
1184 		struct stat sb;
1185 
1186 		n = fprintf(tmpf, "%s\n", GOT_PACKED_REFS_HEADER);
1187 		if (n != sizeof(GOT_PACKED_REFS_HEADER)) {
1188 			err = got_ferror(f, GOT_ERR_IO);
1189 			goto done;
1190 		}
1191 
1192 		SIMPLEQ_FOREACH(re, &refs, entry) {
1193 			uint8_t hex[SHA1_DIGEST_STRING_LENGTH];
1194 
1195 			if (got_sha1_digest_to_str(re->ref->ref.ref.sha1, hex,
1196 			    sizeof(hex)) == NULL) {
1197 				err = got_error(GOT_ERR_BAD_REF_DATA);
1198 				goto done;
1199 			}
1200 			n = fprintf(tmpf, "%s ", hex);
1201 			if (n != sizeof(hex)) {
1202 				err = got_ferror(f, GOT_ERR_IO);
1203 				goto done;
1204 			}
1205 			n = fprintf(tmpf, "%s\n", re->ref->ref.ref.name);
1206 			if (n != strlen(re->ref->ref.ref.name) + 1) {
1207 				err = got_ferror(f, GOT_ERR_IO);
1208 				goto done;
1209 			}
1210 		}
1211 
1212 		if (fflush(tmpf) != 0) {
1213 			err = got_error_from_errno("fflush");
1214 			goto done;
1215 		}
1216 
1217 		if (stat(packed_refs_path, &sb) != 0) {
1218 			if (errno != ENOENT) {
1219 				err = got_error_from_errno2("stat",
1220 				    packed_refs_path);
1221 				goto done;
1222 			}
1223 			sb.st_mode = GOT_DEFAULT_FILE_MODE;
1224 		}
1225 
1226 		if (rename(tmppath, packed_refs_path) != 0) {
1227 			err = got_error_from_errno3("rename", tmppath,
1228 			    packed_refs_path);
1229 			goto done;
1230 		}
1231 
1232 		if (chmod(packed_refs_path, sb.st_mode) != 0) {
1233 			err = got_error_from_errno2("chmod",
1234 			    packed_refs_path);
1235 			goto done;
1236 		}
1237 	}
1238 done:
1239 	if (delref->lf == NULL && lf)
1240 		unlock_err = got_lockfile_unlock(lf);
1241 	if (f) {
1242 		if (fclose(f) != 0 && err == NULL)
1243 			err = got_error_from_errno("fclose");
1244 	}
1245 	if (tmpf) {
1246 		unlink(tmppath);
1247 		if (fclose(tmpf) != 0 && err == NULL)
1248 			err = got_error_from_errno("fclose");
1249 	}
1250 	free(tmppath);
1251 	free(packed_refs_path);
1252 	got_ref_list_free(&refs);
1253 	return err ? err : unlock_err;
1254 }
1255 
1256 const struct got_error *
1257 got_ref_delete(struct got_reference *ref, struct got_repository *repo)
1258 {
1259 	const struct got_error *err = NULL, *unlock_err = NULL;
1260 	const char *name = got_ref_get_name(ref);
1261 	char *path_refs = NULL, *path = NULL;
1262 	struct got_lockfile *lf = NULL;
1263 
1264 	if (ref->flags & GOT_REF_IS_PACKED)
1265 		return delete_packed_ref(ref, repo);
1266 
1267 	path_refs = get_refs_dir_path(repo, name);
1268 	if (path_refs == NULL) {
1269 		err = got_error_from_errno2("get_refs_dir_path", name);
1270 		goto done;
1271 	}
1272 
1273 	if (asprintf(&path, "%s/%s", path_refs, name) == -1) {
1274 		err = got_error_from_errno("asprintf");
1275 		goto done;
1276 	}
1277 
1278 	if (ref->lf == NULL) {
1279 		err = got_lockfile_lock(&lf, path);
1280 		if (err)
1281 			goto done;
1282 	}
1283 
1284 	/* XXX: check if old content matches our expectations? */
1285 
1286 	if (unlink(path) != 0)
1287 		err = got_error_from_errno2("unlink", path);
1288 done:
1289 	if (ref->lf == NULL && lf)
1290 		unlock_err = got_lockfile_unlock(lf);
1291 
1292 	free(path_refs);
1293 	free(path);
1294 	return err ? err : unlock_err;
1295 }
1296 
1297 const struct got_error *
1298 got_ref_unlock(struct got_reference *ref)
1299 {
1300 	const struct got_error *err;
1301 	err = got_lockfile_unlock(ref->lf);
1302 	ref->lf = NULL;
1303 	return err;
1304 }