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Date:: Sat Mar 21 22:44:07 2020 UTC
Message:: make replacing symrefs actually work in 'got fetch'
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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 			if (err->code == GOT_ERR_ERRNO && errno == ENOENT)
178 				err = got_error(GOT_ERR_NOT_REF);
179 			return err;
180 		}
181 	}
182 
183 	f = fopen(abspath, "rb");
184 	if (f == NULL) {
185 		if (lock)
186 			got_lockfile_unlock(lf);
187 		return NULL;
188 	}
189 
190 	linelen = getline(&line, &linesize, f);
191 	if (linelen == -1) {
192 		if (feof(f))
193 			err = NULL; /* ignore empty files (could be locks) */
194 		else
195 			err = got_error_from_errno2("getline", abspath);
196 		if (lock)
197 			got_lockfile_unlock(lf);
198 		goto done;
199 	}
200 	while (linelen > 0 && line[linelen - 1] == '\n') {
201 		line[linelen - 1] = '\0';
202 		linelen--;
203 	}
204 
205 	err = parse_ref_line(ref, name, line);
206 	if (lock) {
207 		if (err)
208 			got_lockfile_unlock(lf);
209 		else {
210 			if (*ref)
211 				(*ref)->lf = lf;
212 			else
213 				got_lockfile_unlock(lf);
214 		}
215 	}
216 done:
217 	free(line);
218 	if (fclose(f) != 0 && err == NULL) {
219 		err = got_error_from_errno("fclose");
220 		if (*ref) {
221 			if (lock)
222 				got_ref_unlock(*ref);
223 			got_ref_close(*ref);
224 			*ref = NULL;
225 		}
226 	}
227 	return err;
228 }
229 
230 static int
231 is_well_known_ref(const char *refname)
232 {
233 	return (strcmp(refname, GOT_REF_HEAD) == 0 ||
234 	    strcmp(refname, GOT_REF_ORIG_HEAD) == 0 ||
235 	    strcmp(refname, GOT_REF_MERGE_HEAD) == 0 ||
236 	    strcmp(refname, GOT_REF_FETCH_HEAD) == 0);
237 }
238 
239 static char *
240 get_refs_dir_path(struct got_repository *repo, const char *refname)
241 {
242 	if (is_well_known_ref(refname) || strncmp(refname, "refs/", 5) == 0)
243 		return strdup(got_repo_get_path_git_dir(repo));
244 
245 	return got_repo_get_path_refs(repo);
246 }
247 
248 static int
249 is_valid_ref_name(const char *name)
250 {
251 	const char *s, *seg;
252 	const char forbidden[] = { ' ', '~', '^', ':', '?', '*', '[' , '\\' };
253 	const char *forbidden_seq[] = { "//", "..", "@{" };
254 	const char *lfs = GOT_LOCKFILE_SUFFIX;
255 	const size_t lfs_len = sizeof(GOT_LOCKFILE_SUFFIX) - 1;
256 	int i;
257 
258 	if (name[0] == '@' && name[1] == '\0')
259 		return 0;
260 
261 	s = name;
262 	seg = s;
263 	if (seg[0] == '\0' || seg[0] == '.' || seg[0] == '/')
264 		return 0;
265 	while (*s) {
266 		for (i = 0; i < nitems(forbidden); i++) {
267 			if (*s == forbidden[i])
268 				return 0;
269 		}
270 		for (i = 0; i < nitems(forbidden_seq); i++) {
271 			if (s[0] == forbidden_seq[i][0] &&
272 			    s[1] == forbidden_seq[i][1])
273 				return 0;
274 		}
275 		if (iscntrl((unsigned char)s[0]))
276 			return 0;
277 		if (s[0] == '.' && s[1] == '\0')
278 			return 0;
279 		if (*s == '/') {
280 			const char *nextseg = s + 1;
281 			if (nextseg[0] == '\0' || nextseg[0] == '.' ||
282 			    nextseg[0] == '/')
283 				return 0;
284 			if (seg <= s - lfs_len &&
285 			    strncmp(s - lfs_len, lfs, lfs_len) == 0)
286 				return 0;
287 			seg = nextseg;
288 		}
289 		s++;
290 	}
291 
292 	if (seg <= s - lfs_len &&
293 	    strncmp(s - lfs_len, lfs, lfs_len) == 0)
294 		return 0;
295 
296 	return 1;
297 }
298 
299 const struct got_error *
300 got_ref_alloc(struct got_reference **ref, const char *name,
301     struct got_object_id *id)
302 {
303 	if (!is_valid_ref_name(name))
304 		return got_error_path(name, GOT_ERR_BAD_REF_NAME);
305 
306 	return alloc_ref(ref, name, id, 0);
307 }
308 
309 const struct got_error *
310 got_ref_alloc_symref(struct got_reference **ref, const char *name,
311 	struct got_reference *target_ref)
312 {
313 	if (!is_valid_ref_name(name))
314 		return got_error_path(name, GOT_ERR_BAD_REF_NAME);
315 
316 	return alloc_symref(ref, name, got_ref_get_name(target_ref), 0);
317 }
318 
319 static const struct got_error *
320 parse_packed_ref_line(struct got_reference **ref, const char *abs_refname,
321     const char *line)
322 {
323 	struct got_object_id id;
324 	const char *name;
325 
326 	*ref = NULL;
327 
328 	if (line[0] == '#' || line[0] == '^')
329 		return NULL;
330 
331 	if (!got_parse_sha1_digest(id.sha1, line))
332 		return got_error(GOT_ERR_BAD_REF_DATA);
333 
334 	if (abs_refname) {
335 		if (strcmp(line + SHA1_DIGEST_STRING_LENGTH, abs_refname) != 0)
336 			return NULL;
337 		name = abs_refname;
338 	} else
339 		name = line + SHA1_DIGEST_STRING_LENGTH;
340 
341 	return alloc_ref(ref, name, &id, GOT_REF_IS_PACKED);
342 }
343 
344 static const struct got_error *
345 open_packed_ref(struct got_reference **ref, FILE *f, const char **subdirs,
346     int nsubdirs, const char *refname)
347 {
348 	const struct got_error *err = NULL;
349 	char *abs_refname;
350 	char *line;
351 	size_t len;
352 	const char delim[3] = {'\0', '\0', '\0'};
353 	int i, ref_is_absolute = (strncmp(refname, "refs/", 5) == 0);
354 
355 	*ref = NULL;
356 
357 	if (ref_is_absolute)
358 		abs_refname = (char *)refname;
359 	do {
360 		line = fparseln(f, &len, NULL, delim, 0);
361 		if (line == NULL) {
362 			if (feof(f))
363 				break;
364 			err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
365 			break;
366 		}
367 		for (i = 0; i < nsubdirs; i++) {
368 			if (!ref_is_absolute &&
369 			    asprintf(&abs_refname, "refs/%s/%s", subdirs[i],
370 			    refname) == -1)
371 				return got_error_from_errno("asprintf");
372 			err = parse_packed_ref_line(ref, abs_refname, line);
373 			if (!ref_is_absolute)
374 				free(abs_refname);
375 			if (err || *ref != NULL)
376 				break;
377 		}
378 		free(line);
379 		if (err)
380 			break;
381 	} while (*ref == NULL);
382 
383 	return err;
384 }
385 
386 static const struct got_error *
387 open_ref(struct got_reference **ref, const char *path_refs, const char *subdir,
388     const char *name, int lock)
389 {
390 	const struct got_error *err = NULL;
391 	char *path = NULL;
392 	char *absname = NULL;
393 	int ref_is_absolute = (strncmp(name, "refs/", 5) == 0);
394 	int ref_is_well_known = is_well_known_ref(name);
395 
396 	*ref = NULL;
397 
398 	if (ref_is_absolute || ref_is_well_known) {
399 		if (asprintf(&path, "%s/%s", path_refs, name) == -1)
400 			return got_error_from_errno("asprintf");
401 		absname = (char *)name;
402 	} else {
403 		if (asprintf(&path, "%s/%s%s%s", path_refs, subdir,
404 		    subdir[0] ? "/" : "", name) == -1)
405 			return got_error_from_errno("asprintf");
406 
407 		if (asprintf(&absname, "refs/%s%s%s",
408 		    subdir, subdir[0] ? "/" : "", name) == -1) {
409 			err = got_error_from_errno("asprintf");
410 			goto done;
411 		}
412 	}
413 
414 	err = parse_ref_file(ref, absname, path, lock);
415 done:
416 	if (!ref_is_absolute && !ref_is_well_known)
417 		free(absname);
418 	free(path);
419 	return err;
420 }
421 
422 const struct got_error *
423 got_ref_open(struct got_reference **ref, struct got_repository *repo,
424    const char *refname, int lock)
425 {
426 	const struct got_error *err = NULL;
427 	char *path_refs = NULL;
428 	const char *subdirs[] = {
429 	    GOT_REF_HEADS, GOT_REF_TAGS, GOT_REF_REMOTES
430 	};
431 	int i, well_known = is_well_known_ref(refname);
432 	struct got_lockfile *lf = NULL;
433 
434 	*ref = NULL;
435 
436 	path_refs = get_refs_dir_path(repo, refname);
437 	if (path_refs == NULL) {
438 		err = got_error_from_errno2("get_refs_dir_path", refname);
439 		goto done;
440 	}
441 
442 	if (well_known) {
443 		err = open_ref(ref, path_refs, "", refname, lock);
444 	} else {
445 		char *packed_refs_path;
446 		FILE *f;
447 
448 		/* Search on-disk refs before packed refs! */
449 		for (i = 0; i < nitems(subdirs); i++) {
450 			err = open_ref(ref, path_refs, subdirs[i], refname,
451 			    lock);
452 			if (err || *ref)
453 				goto done;
454 		}
455 
456 		packed_refs_path = got_repo_get_path_packed_refs(repo);
457 		if (packed_refs_path == NULL) {
458 			err = got_error_from_errno(
459 			    "got_repo_get_path_packed_refs");
460 			goto done;
461 		}
462 
463 		if (lock) {
464 			err = got_lockfile_lock(&lf, packed_refs_path);
465 			if (err)
466 				goto done;
467 		}
468 		f = fopen(packed_refs_path, "rb");
469 		free(packed_refs_path);
470 		if (f != NULL) {
471 			err = open_packed_ref(ref, f, subdirs, nitems(subdirs),
472 			    refname);
473 			if (!err) {
474 				if (fclose(f) != 0) {
475 					err = got_error_from_errno("fclose");
476 					got_ref_close(*ref);
477 					*ref = NULL;
478 				} else if (*ref)
479 					(*ref)->lf = lf;
480 			}
481 		}
482 	}
483 done:
484 	if (!err && *ref == NULL)
485 		err = got_error_not_ref(refname);
486 	if (err && lf)
487 		got_lockfile_unlock(lf);
488 	free(path_refs);
489 	return err;
490 }
491 
492 void
493 got_ref_close(struct got_reference *ref)
494 {
495 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
496 		free(ref->ref.symref.name);
497 		free(ref->ref.symref.ref);
498 	} else
499 		free(ref->ref.ref.name);
500 	free(ref);
501 }
502 
503 struct got_reference *
504 got_ref_dup(struct got_reference *ref)
505 {
506 	struct got_reference *ret;
507 
508 	ret = calloc(1, sizeof(*ret));
509 	if (ret == NULL)
510 		return NULL;
511 
512 	ret->flags = ref->flags;
513 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
514 		ret->ref.symref.name = strdup(ref->ref.symref.name);
515 		if (ret->ref.symref.name == NULL) {
516 			free(ret);
517 			return NULL;
518 		}
519 		ret->ref.symref.ref = strdup(ref->ref.symref.ref);
520 		if (ret->ref.symref.ref == NULL) {
521 			free(ret->ref.symref.name);
522 			free(ret);
523 			return NULL;
524 		}
525 	} else {
526 		ref->ref.ref.name = strdup(ref->ref.ref.name);
527 		if (ref->ref.ref.name == NULL) {
528 			free(ret);
529 			return NULL;
530 		}
531 		memcpy(ret->ref.ref.sha1, ref->ref.ref.sha1,
532 		    sizeof(ret->ref.ref.sha1));
533 	}
534 
535 	return ret;
536 }
537 
538 const struct got_error *
539 got_reflist_entry_dup(struct got_reflist_entry **newp,
540     struct got_reflist_entry *re)
541 {
542 	const struct got_error *err = NULL;
543 	struct got_reflist_entry *new;
544 
545 	*newp = NULL;
546 
547 	new = malloc(sizeof(*new));
548 	if (new == NULL)
549 		return got_error_from_errno("malloc");
550 
551 	new->ref = got_ref_dup(re->ref);
552 	if (new->ref == NULL) {
553 		err = got_error_from_errno("got_ref_dup");
554 		free(new);
555 		return err;
556 	}
557 
558 	new->id = got_object_id_dup(re->id);
559 	if (new->id == NULL) {
560 		err = got_error_from_errno("got_ref_dup");
561 		free(new->id);
562 		free(new);
563 		return err;
564 	}
565 
566 	*newp = new;
567 	return NULL;
568 }
569 
570 static const struct got_error *
571 resolve_symbolic_ref(struct got_reference **resolved,
572     struct got_repository *repo, struct got_reference *ref)
573 {
574 	struct got_reference *nextref;
575 	const struct got_error *err;
576 
577 	err = got_ref_open(&nextref, repo, ref->ref.symref.ref, 0);
578 	if (err)
579 		return err;
580 
581 	if (nextref->flags & GOT_REF_IS_SYMBOLIC)
582 		err = resolve_symbolic_ref(resolved, repo, nextref);
583 	else
584 		*resolved = got_ref_dup(nextref);
585 
586 	got_ref_close(nextref);
587 	return err;
588 }
589 
590 static const struct got_error *
591 ref_resolve(struct got_object_id **id, struct got_repository *repo,
592     struct got_reference *ref, int recursion)
593 {
594 	const struct got_error *err;
595 
596 	if (recursion <= 0)
597 		return got_error_msg(GOT_ERR_RECURSION,
598 		    "reference recursion limit reached");
599 
600 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
601 		struct got_reference *resolved = NULL;
602 		err = resolve_symbolic_ref(&resolved, repo, ref);
603 		if (err == NULL)
604 			err = ref_resolve(id, repo, resolved, --recursion);
605 		if (resolved)
606 			got_ref_close(resolved);
607 		return err;
608 	}
609 
610 	*id = calloc(1, sizeof(**id));
611 	if (*id == NULL)
612 		return got_error_from_errno("calloc");
613 	memcpy((*id)->sha1, ref->ref.ref.sha1, sizeof((*id)->sha1));
614 	return NULL;
615 }
616 
617 const struct got_error *
618 got_ref_resolve(struct got_object_id **id, struct got_repository *repo,
619     struct got_reference *ref)
620 {
621 	return ref_resolve(id, repo, ref, GOT_REF_RECURSE_MAX);
622 }
623 
624 char *
625 got_ref_to_str(struct got_reference *ref)
626 {
627 	char *str;
628 
629 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
630 		return strdup(ref->ref.symref.ref);
631 
632 	str = malloc(SHA1_DIGEST_STRING_LENGTH);
633 	if (str == NULL)
634 		return NULL;
635 
636 	if (got_sha1_digest_to_str(ref->ref.ref.sha1, str,
637 	    SHA1_DIGEST_STRING_LENGTH) == NULL) {
638 		free(str);
639 		return NULL;
640 	}
641 
642 	return str;
643 }
644 
645 const char *
646 got_ref_get_name(struct got_reference *ref)
647 {
648 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
649 		return ref->ref.symref.name;
650 
651 	return ref->ref.ref.name;
652 }
653 
654 const char *
655 got_ref_get_symref_target(struct got_reference *ref)
656 {
657 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
658 		return ref->ref.symref.ref;
659 
660 	return NULL;
661 }
662 
663 const struct got_error *
664 got_ref_cmp_by_name(void *arg, int *cmp, struct got_reference *re1,
665     struct got_reference* re2)
666 {
667 	const char *name1 = got_ref_get_name(re1);
668 	const char *name2 = got_ref_get_name(re2);
669 
670 	*cmp = got_path_cmp(name1, name2, strlen(name1), strlen(name2));
671 	return NULL;
672 }
673 
674 const struct got_error *
675 got_ref_cmp_tags(void *arg, int *cmp, struct got_reference *ref1,
676     struct got_reference *ref2)
677 {
678 	const struct got_error *err = NULL;
679 	struct got_repository *repo = arg;
680 	struct got_object_id *id1, *id2 = NULL;
681 	struct got_tag_object *tag1 = NULL, *tag2 = NULL;
682 	struct got_commit_object *commit1 = NULL, *commit2 = NULL;
683 	time_t time1, time2;
684 
685 	*cmp = 0;
686 
687 	err = got_ref_resolve(&id1, repo, ref1);
688 	if (err)
689 		return err;
690 	err = got_object_open_as_tag(&tag1, repo, id1);
691 	if (err) {
692 		if (err->code != GOT_ERR_OBJ_TYPE)
693 			goto done;
694 		/* "lightweight" tag */
695 		err = got_object_open_as_commit(&commit1, repo, id1);
696 		if (err)
697 			goto done;
698 		time1 = got_object_commit_get_committer_time(commit1);
699 	} else
700 		time1 = got_object_tag_get_tagger_time(tag1);
701 
702 	err = got_ref_resolve(&id2, repo, ref2);
703 	if (err)
704 		goto done;
705 	err = got_object_open_as_tag(&tag2, repo, id2);
706 	if (err) {
707 		if (err->code != GOT_ERR_OBJ_TYPE)
708 			goto done;
709 		/* "lightweight" tag */
710 		err = got_object_open_as_commit(&commit2, repo, id2);
711 		if (err)
712 			goto done;
713 		time2 = got_object_commit_get_committer_time(commit2);
714 	} else
715 		time2 = got_object_tag_get_tagger_time(tag2);
716 
717 	/* Put latest tags first. */
718 	if (time1 < time2)
719 		*cmp = 1;
720 	else if (time1 > time2)
721 		*cmp = -1;
722 	else
723 		err = got_ref_cmp_by_name(NULL, cmp, ref2, ref1);
724 done:
725 	free(id1);
726 	free(id2);
727 	if (tag1)
728 		got_object_tag_close(tag1);
729 	if (tag2)
730 		got_object_tag_close(tag2);
731 	if (commit1)
732 		got_object_commit_close(commit1);
733 	if (commit2)
734 		got_object_commit_close(commit2);
735 	return err;
736 }
737 
738 static const struct got_error *
739 insert_ref(struct got_reflist_entry **newp, struct got_reflist_head *refs,
740     struct got_reference *ref, struct got_repository *repo,
741     got_ref_cmp_cb cmp_cb, void *cmp_arg)
742 {
743 	const struct got_error *err;
744 	struct got_object_id *id;
745 	struct got_reflist_entry *new, *re, *prev = NULL;
746 	int cmp;
747 
748 	*newp = NULL;
749 
750 	err = got_ref_resolve(&id, repo, ref);
751 	if (err)
752 		return err;
753 
754 	new = malloc(sizeof(*new));
755 	if (new == NULL) {
756 		free(id);
757 		return got_error_from_errno("malloc");
758 	}
759 	new->ref = ref;
760 	new->id = id;
761 	*newp = new;
762 
763 	/*
764 	 * We must de-duplicate entries on insert because packed-refs may
765 	 * contain redundant entries. On-disk refs take precedence.
766 	 * This code assumes that on-disk revs are read before packed-refs.
767 	 * We're iterating the list anyway, so insert elements sorted by name.
768 	 */
769 	re = SIMPLEQ_FIRST(refs);
770 	while (re) {
771 		err = (*cmp_cb)(cmp_arg, &cmp, re->ref, new->ref);
772 		if (err)
773 			return err;
774 		if (cmp == 0) {
775 			/* duplicate */
776 			free(new->id);
777 			free(new);
778 			*newp = NULL;
779 			return NULL;
780 		} else if (cmp > 0) {
781 			if (prev)
782 				SIMPLEQ_INSERT_AFTER(refs, prev, new, entry);
783 			else
784 				SIMPLEQ_INSERT_HEAD(refs, new, entry);
785 			return NULL;
786 		} else {
787 			prev = re;
788 			re = SIMPLEQ_NEXT(re, entry);
789 		}
790 	}
791 
792 	SIMPLEQ_INSERT_TAIL(refs, new, entry);
793 	return NULL;
794 }
795 
796 static const struct got_error *
797 gather_on_disk_refs(struct got_reflist_head *refs, const char *path_refs,
798     const char *subdir, struct got_repository *repo,
799     got_ref_cmp_cb cmp_cb, void *cmp_arg)
800 {
801 	const struct got_error *err = NULL;
802 	DIR *d = NULL;
803 	char *path_subdir;
804 
805 	if (asprintf(&path_subdir, "%s/%s", path_refs, subdir) == -1)
806 		return got_error_from_errno("asprintf");
807 
808 	d = opendir(path_subdir);
809 	if (d == NULL)
810 		goto done;
811 
812 	for (;;) {
813 		struct dirent *dent;
814 		struct got_reference *ref;
815 		char *child;
816 
817 		dent = readdir(d);
818 		if (dent == NULL)
819 			break;
820 
821 		if (strcmp(dent->d_name, ".") == 0 ||
822 		    strcmp(dent->d_name, "..") == 0)
823 			continue;
824 
825 		switch (dent->d_type) {
826 		case DT_REG:
827 			err = open_ref(&ref, path_refs, subdir, dent->d_name,
828 			    0);
829 			if (err)
830 				goto done;
831 			if (ref) {
832 				struct got_reflist_entry *new;
833 				err = insert_ref(&new, refs, ref, repo,
834 				    cmp_cb, cmp_arg);
835 				if (err || new == NULL /* duplicate */)
836 					got_ref_close(ref);
837 				if (err)
838 					goto done;
839 			}
840 			break;
841 		case DT_DIR:
842 			if (asprintf(&child, "%s%s%s", subdir,
843 			    subdir[0] == '\0' ? "" : "/", dent->d_name) == -1) {
844 				err = got_error_from_errno("asprintf");
845 				break;
846 			}
847 			err = gather_on_disk_refs(refs, path_refs, child, repo,
848 			    cmp_cb, cmp_arg);
849 			free(child);
850 			break;
851 		default:
852 			break;
853 		}
854 	}
855 done:
856 	if (d)
857 		closedir(d);
858 	free(path_subdir);
859 	return err;
860 }
861 
862 const struct got_error *
863 got_ref_list(struct got_reflist_head *refs, struct got_repository *repo,
864     const char *ref_namespace, got_ref_cmp_cb cmp_cb, void *cmp_arg)
865 {
866 	const struct got_error *err;
867 	char *packed_refs_path, *path_refs = NULL;
868 	const char *ondisk_ref_namespace = NULL;
869 	FILE *f = NULL;
870 	struct got_reference *ref;
871 	struct got_reflist_entry *new;
872 
873 	if (ref_namespace == NULL || ref_namespace[0] == '\0') {
874 		path_refs = get_refs_dir_path(repo, GOT_REF_HEAD);
875 		if (path_refs == NULL) {
876 			err = got_error_from_errno("get_refs_dir_path");
877 			goto done;
878 		}
879 		err = open_ref(&ref, path_refs, "", GOT_REF_HEAD, 0);
880 		if (err)
881 			goto done;
882 		err = insert_ref(&new, refs, ref, repo,
883 		    cmp_cb, cmp_arg);
884 		if (err || new == NULL /* duplicate */)
885 			got_ref_close(ref);
886 		if (err && err->code != GOT_ERR_NOT_REF)
887 			goto done;
888 	}
889 
890 	ondisk_ref_namespace = ref_namespace;
891 	if (ref_namespace && strncmp(ref_namespace, "refs/", 5) == 0)
892 		ondisk_ref_namespace += 5;
893 
894 	/* Gather on-disk refs before parsing packed-refs. */
895 	free(path_refs);
896 	path_refs = get_refs_dir_path(repo, "");
897 	if (path_refs == NULL) {
898 		err = got_error_from_errno("get_refs_dir_path");
899 		goto done;
900 	}
901 	err = gather_on_disk_refs(refs, path_refs,
902 	    ondisk_ref_namespace ? ondisk_ref_namespace : "", repo,
903 	    cmp_cb, cmp_arg);
904 	if (err)
905 		goto done;
906 
907 	/*
908 	 * The packed-refs file may contain redundant entries, in which
909 	 * case on-disk refs take precedence.
910 	 */
911 	packed_refs_path = got_repo_get_path_packed_refs(repo);
912 	if (packed_refs_path == NULL) {
913 		err = got_error_from_errno("got_repo_get_path_packed_refs");
914 		goto done;
915 	}
916 
917 	f = fopen(packed_refs_path, "r");
918 	free(packed_refs_path);
919 	if (f) {
920 		char *line;
921 		size_t len;
922 		const char delim[3] = {'\0', '\0', '\0'};
923 		for (;;) {
924 			line = fparseln(f, &len, NULL, delim, 0);
925 			if (line == NULL) {
926 				if (feof(f))
927 					break;
928 				err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
929 				goto done;
930 			}
931 			err = parse_packed_ref_line(&ref, NULL, line);
932 			free(line);
933 			if (err)
934 				goto done;
935 			if (ref) {
936 				if (ref_namespace) {
937 					const char *name;
938 					name = got_ref_get_name(ref);
939 					if (strncmp(name, ref_namespace,
940 					    strlen(ref_namespace)) != 0) {
941 						got_ref_close(ref);
942 						continue;
943 					}
944 				}
945 				err = insert_ref(&new, refs, ref, repo,
946 				    cmp_cb, cmp_arg);
947 				if (err || new == NULL /* duplicate */)
948 					got_ref_close(ref);
949 				if (err)
950 					goto done;
951 			}
952 		}
953 	}
954 done:
955 	free(path_refs);
956 	if (f && fclose(f) != 0 && err == NULL)
957 		err = got_error_from_errno("fclose");
958 	return err;
959 }
960 
961 void
962 got_ref_list_free(struct got_reflist_head *refs)
963 {
964 	struct got_reflist_entry *re;
965 
966 	while (!SIMPLEQ_EMPTY(refs)) {
967 		re = SIMPLEQ_FIRST(refs);
968 		SIMPLEQ_REMOVE_HEAD(refs, entry);
969 		got_ref_close(re->ref);
970 		free(re->id);
971 		free(re);
972 	}
973 
974 }
975 
976 int
977 got_ref_is_symbolic(struct got_reference *ref)
978 {
979 	return (ref->flags & GOT_REF_IS_SYMBOLIC);
980 }
981 
982 const struct got_error *
983 got_ref_change_ref(struct got_reference *ref, struct got_object_id *id)
984 {
985 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
986 		return got_error(GOT_ERR_BAD_REF_TYPE);
987 
988 	memcpy(ref->ref.ref.sha1, id->sha1, sizeof(ref->ref.ref.sha1));
989 	return NULL;
990 }
991 
992 const struct got_error *
993 got_ref_change_symref(struct got_reference *ref, char *refname)
994 {
995 	char *new_name;
996 
997 	if ((ref->flags & GOT_REF_IS_SYMBOLIC) == 0)
998 		return got_error(GOT_ERR_BAD_REF_TYPE);
999 
1000 	new_name = strdup(refname);
1001 	if (new_name == NULL)
1002 		return got_error_from_errno("strdup");
1003 
1004 	free(ref->ref.symref.name);
1005 	ref->ref.symref.name = new_name;
1006 	return NULL;
1007 }
1008 
1009 const struct got_error *
1010 got_ref_change_symref_to_ref(struct got_reference *symref,
1011     struct got_object_id *id)
1012 {
1013 	if ((symref->flags & GOT_REF_IS_SYMBOLIC) == 0)
1014 		return got_error(GOT_ERR_BAD_REF_TYPE);
1015 
1016 	symref->ref.ref.name = symref->ref.symref.name;
1017 	memcpy(symref->ref.ref.sha1, id->sha1, SHA1_DIGEST_LENGTH);
1018 	symref->flags &= ~GOT_REF_IS_SYMBOLIC;
1019 	return NULL;
1020 }
1021 
1022 const struct got_error *
1023 got_ref_write(struct got_reference *ref, struct got_repository *repo)
1024 {
1025 	const struct got_error *err = NULL, *unlock_err = NULL;
1026 	const char *name = got_ref_get_name(ref);
1027 	char *path_refs = NULL, *path = NULL, *tmppath = NULL;
1028 	struct got_lockfile *lf = NULL;
1029 	FILE *f = NULL;
1030 	size_t n;
1031 	struct stat sb;
1032 
1033 	path_refs = get_refs_dir_path(repo, name);
1034 	if (path_refs == NULL) {
1035 		err = got_error_from_errno2("get_refs_dir_path", name);
1036 		goto done;
1037 	}
1038 
1039 	if (asprintf(&path, "%s/%s", path_refs, name) == -1) {
1040 		err = got_error_from_errno("asprintf");
1041 		goto done;
1042 	}
1043 
1044 	err = got_opentemp_named(&tmppath, &f, path);
1045 	if (err) {
1046 		char *parent;
1047 		if (!(err->code == GOT_ERR_ERRNO && errno == ENOENT))
1048 			goto done;
1049 		err = got_path_dirname(&parent, path);
1050 		if (err)
1051 			goto done;
1052 		err = got_path_mkdir(parent);
1053 		free(parent);
1054 		if (err)
1055 			goto done;
1056 		err = got_opentemp_named(&tmppath, &f, path);
1057 		if (err)
1058 			goto done;
1059 	}
1060 
1061 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
1062 		n = fprintf(f, "ref: %s\n", ref->ref.symref.ref);
1063 		if (n != strlen(ref->ref.symref.ref) + 6) {
1064 			err = got_ferror(f, GOT_ERR_IO);
1065 			goto done;
1066 		}
1067 	} else {
1068 		char hex[SHA1_DIGEST_STRING_LENGTH];
1069 		if (got_sha1_digest_to_str(ref->ref.ref.sha1, hex,
1070 		    sizeof(hex)) == NULL) {
1071 			err = got_error(GOT_ERR_BAD_REF_DATA);
1072 			goto done;
1073 		}
1074 		n = fprintf(f, "%s\n", hex);
1075 		if (n != sizeof(hex)) {
1076 			err = got_ferror(f, GOT_ERR_IO);
1077 			goto done;
1078 		}
1079 	}
1080 
1081 	if (ref->lf == NULL) {
1082 		err = got_lockfile_lock(&lf, path);
1083 		if (err)
1084 			goto done;
1085 	}
1086 
1087 	/* XXX: check if old content matches our expectations? */
1088 
1089 	if (stat(path, &sb) != 0) {
1090 		if (errno != ENOENT) {
1091 			err = got_error_from_errno2("stat", path);
1092 			goto done;
1093 		}
1094 		sb.st_mode = GOT_DEFAULT_FILE_MODE;
1095 	}
1096 
1097 	if (rename(tmppath, path) != 0) {
1098 		err = got_error_from_errno3("rename", tmppath, path);
1099 		goto done;
1100 	}
1101 	free(tmppath);
1102 	tmppath = NULL;
1103 
1104 	if (chmod(path, sb.st_mode) != 0) {
1105 		err = got_error_from_errno2("chmod", path);
1106 		goto done;
1107 	}
1108 done:
1109 	if (ref->lf == NULL && lf)
1110 		unlock_err = got_lockfile_unlock(lf);
1111 	if (f) {
1112 		if (fclose(f) != 0 && err == NULL)
1113 			err = got_error_from_errno("fclose");
1114 	}
1115 	free(path_refs);
1116 	free(path);
1117 	if (tmppath) {
1118 		if (unlink(tmppath) != 0 && err == NULL)
1119 			err = got_error_from_errno2("unlink", tmppath);
1120 		free(tmppath);
1121 	}
1122 	return err ? err : unlock_err;
1123 }
1124 
1125 static const struct got_error *
1126 delete_packed_ref(struct got_reference *delref, struct got_repository *repo)
1127 {
1128 	const struct got_error *err = NULL, *unlock_err = NULL;
1129 	struct got_lockfile *lf = NULL;
1130 	FILE *f = NULL, *tmpf = NULL;
1131 	char *packed_refs_path, *tmppath = NULL;
1132 	struct got_reflist_head refs;
1133 	int found_delref = 0;
1134 
1135 	/* The packed-refs file does not cotain symbolic references. */
1136 	if (delref->flags & GOT_REF_IS_SYMBOLIC)
1137 		return got_error(GOT_ERR_BAD_REF_DATA);
1138 
1139 	SIMPLEQ_INIT(&refs);
1140 
1141 	packed_refs_path = got_repo_get_path_packed_refs(repo);
1142 	if (packed_refs_path == NULL)
1143 		return got_error_from_errno("got_repo_get_path_packed_refs");
1144 
1145 	err = got_opentemp_named(&tmppath, &tmpf, packed_refs_path);
1146 	if (err)
1147 		goto done;
1148 
1149 	if (delref->lf == NULL) {
1150 		err = got_lockfile_lock(&lf, packed_refs_path);
1151 		if (err)
1152 			goto done;
1153 	}
1154 
1155 	f = fopen(packed_refs_path, "r");
1156 	if (f == NULL) {
1157 		err = got_error_from_errno2("fopen", packed_refs_path);
1158 		goto done;
1159 	}
1160 	for (;;) {
1161 		char *line;
1162 		size_t len;
1163 		const char delim[3] = {'\0', '\0', '\0'};
1164 		struct got_reference *ref;
1165 		struct got_reflist_entry *new;
1166 
1167 		line = fparseln(f, &len, NULL, delim, 0);
1168 		if (line == NULL) {
1169 			if (feof(f))
1170 				break;
1171 			err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
1172 			goto done;
1173 		}
1174 		err = parse_packed_ref_line(&ref, NULL, line);
1175 		free(line);
1176 		if (err)
1177 			goto done;
1178 		if (ref == NULL)
1179 			continue;
1180 
1181 		if (strcmp(ref->ref.ref.name, delref->ref.ref.name) == 0 &&
1182 		    memcmp(ref->ref.ref.sha1, delref->ref.ref.sha1,
1183 		    sizeof(delref->ref.ref.sha1)) == 0) {
1184 			found_delref = 1;
1185 			got_ref_close(ref);
1186 			continue;
1187 		}
1188 
1189 		err = insert_ref(&new, &refs, ref, repo,
1190 		    got_ref_cmp_by_name, NULL);
1191 		if (err || new == NULL /* duplicate */)
1192 			got_ref_close(ref);
1193 		if (err)
1194 			goto done;
1195 	}
1196 
1197 	if (found_delref) {
1198 		struct got_reflist_entry *re;
1199 		size_t n;
1200 		struct stat sb;
1201 
1202 		n = fprintf(tmpf, "%s\n", GOT_PACKED_REFS_HEADER);
1203 		if (n != sizeof(GOT_PACKED_REFS_HEADER)) {
1204 			err = got_ferror(f, GOT_ERR_IO);
1205 			goto done;
1206 		}
1207 
1208 		SIMPLEQ_FOREACH(re, &refs, entry) {
1209 			uint8_t hex[SHA1_DIGEST_STRING_LENGTH];
1210 
1211 			if (got_sha1_digest_to_str(re->ref->ref.ref.sha1, hex,
1212 			    sizeof(hex)) == NULL) {
1213 				err = got_error(GOT_ERR_BAD_REF_DATA);
1214 				goto done;
1215 			}
1216 			n = fprintf(tmpf, "%s ", hex);
1217 			if (n != sizeof(hex)) {
1218 				err = got_ferror(f, GOT_ERR_IO);
1219 				goto done;
1220 			}
1221 			n = fprintf(tmpf, "%s\n", re->ref->ref.ref.name);
1222 			if (n != strlen(re->ref->ref.ref.name) + 1) {
1223 				err = got_ferror(f, GOT_ERR_IO);
1224 				goto done;
1225 			}
1226 		}
1227 
1228 		if (fflush(tmpf) != 0) {
1229 			err = got_error_from_errno("fflush");
1230 			goto done;
1231 		}
1232 
1233 		if (stat(packed_refs_path, &sb) != 0) {
1234 			if (errno != ENOENT) {
1235 				err = got_error_from_errno2("stat",
1236 				    packed_refs_path);
1237 				goto done;
1238 			}
1239 			sb.st_mode = GOT_DEFAULT_FILE_MODE;
1240 		}
1241 
1242 		if (rename(tmppath, packed_refs_path) != 0) {
1243 			err = got_error_from_errno3("rename", tmppath,
1244 			    packed_refs_path);
1245 			goto done;
1246 		}
1247 
1248 		if (chmod(packed_refs_path, sb.st_mode) != 0) {
1249 			err = got_error_from_errno2("chmod",
1250 			    packed_refs_path);
1251 			goto done;
1252 		}
1253 	}
1254 done:
1255 	if (delref->lf == NULL && lf)
1256 		unlock_err = got_lockfile_unlock(lf);
1257 	if (f) {
1258 		if (fclose(f) != 0 && err == NULL)
1259 			err = got_error_from_errno("fclose");
1260 	}
1261 	if (tmpf) {
1262 		unlink(tmppath);
1263 		if (fclose(tmpf) != 0 && err == NULL)
1264 			err = got_error_from_errno("fclose");
1265 	}
1266 	free(tmppath);
1267 	free(packed_refs_path);
1268 	got_ref_list_free(&refs);
1269 	return err ? err : unlock_err;
1270 }
1271 
1272 const struct got_error *
1273 got_ref_delete(struct got_reference *ref, struct got_repository *repo)
1274 {
1275 	const struct got_error *err = NULL, *unlock_err = NULL;
1276 	const char *name = got_ref_get_name(ref);
1277 	char *path_refs = NULL, *path = NULL;
1278 	struct got_lockfile *lf = NULL;
1279 
1280 	if (ref->flags & GOT_REF_IS_PACKED)
1281 		return delete_packed_ref(ref, repo);
1282 
1283 	path_refs = get_refs_dir_path(repo, name);
1284 	if (path_refs == NULL) {
1285 		err = got_error_from_errno2("get_refs_dir_path", name);
1286 		goto done;
1287 	}
1288 
1289 	if (asprintf(&path, "%s/%s", path_refs, name) == -1) {
1290 		err = got_error_from_errno("asprintf");
1291 		goto done;
1292 	}
1293 
1294 	if (ref->lf == NULL) {
1295 		err = got_lockfile_lock(&lf, path);
1296 		if (err)
1297 			goto done;
1298 	}
1299 
1300 	/* XXX: check if old content matches our expectations? */
1301 
1302 	if (unlink(path) != 0)
1303 		err = got_error_from_errno2("unlink", path);
1304 done:
1305 	if (ref->lf == NULL && lf)
1306 		unlock_err = got_lockfile_unlock(lf);
1307 
1308 	free(path_refs);
1309 	free(path);
1310 	return err ? err : unlock_err;
1311 }
1312 
1313 const struct got_error *
1314 got_ref_unlock(struct got_reference *ref)
1315 {
1316 	const struct got_error *err;
1317 	err = got_lockfile_unlock(ref->lf);
1318 	ref->lf = NULL;
1319 	return err;
1320 }