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Date:: Mon Oct 21 09:04:57 2019 UTC
Message:: ignore empty files in refs directory; convert parse_ref_file() to getline(3)
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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 <sha1.h>
25 #include <stdio.h>
26 #include <stdlib.h>
27 #include <string.h>
28 #include <util.h>
29 #include <zlib.h>
30 #include <time.h>
31 #include <libgen.h>
32 
33 #include "got_error.h"
34 #include "got_object.h"
35 #include "got_repository.h"
36 #include "got_reference.h"
37 #include "got_opentemp.h"
38 #include "got_path.h"
39 
40 #include "got_lib_sha1.h"
41 #include "got_lib_delta.h"
42 #include "got_lib_inflate.h"
43 #include "got_lib_object.h"
44 #include "got_lib_lockfile.h"
45 
46 #ifndef nitems
47 #define nitems(_a) (sizeof(_a) / sizeof((_a)[0]))
48 #endif
49 
50 #define GOT_REF_HEADS	"heads"
51 #define GOT_REF_TAGS	"tags"
52 #define GOT_REF_REMOTES	"remotes"
53 
54 /*
55  * We do not resolve tags yet, and don't yet care about sorting refs either,
56  * so packed-refs files we write contain a minimal header which disables all
57  * packed-refs "traits" supported by Git.
58  */
59 #define GOT_PACKED_REFS_HEADER	"# pack-refs with:"
60 
61 /* A symbolic reference. */
62 struct got_symref {
63 	char *name;
64 	char *ref;
65 };
66 
67 #define GOT_REF_RECURSE_MAX	20
68 
69 /* A non-symbolic reference (there is no better designation). */
70 struct got_ref {
71 	char *name;
72 	u_int8_t sha1[SHA1_DIGEST_LENGTH];
73 };
74 
75 /* A reference which points to an arbitrary object. */
76 struct got_reference {
77 	unsigned int flags;
78 #define GOT_REF_IS_SYMBOLIC	0x01
79 #define GOT_REF_IS_PACKED	0x02
80 
81 	union {
82 		struct got_ref ref;
83 		struct got_symref symref;
84 	} ref;
85 
86 	struct got_lockfile *lf;
87 };
88 
89 static const struct got_error *
90 alloc_ref(struct got_reference **ref, const char *name,
91     struct got_object_id *id, int flags)
92 {
93 	const struct got_error *err = NULL;
94 
95 	*ref = calloc(1, sizeof(**ref));
96 	if (*ref == NULL)
97 		return got_error_from_errno("calloc");
98 
99 	memcpy((*ref)->ref.ref.sha1, id->sha1, sizeof((*ref)->ref.ref.sha1));
100 	(*ref)->flags = flags;
101 	(*ref)->ref.ref.name = strdup(name);
102 	if ((*ref)->ref.ref.name == NULL) {
103 		err = got_error_from_errno("strdup");
104 		got_ref_close(*ref);
105 		*ref = NULL;
106 	}
107 	return err;
108 }
109 
110 static const struct got_error *
111 alloc_symref(struct got_reference **ref, const char *name,
112     const char *target_ref, int flags)
113 {
114 	const struct got_error *err = NULL;
115 
116 	*ref = calloc(1, sizeof(**ref));
117 	if (*ref == NULL)
118 		return got_error_from_errno("calloc");
119 
120 	(*ref)->flags = GOT_REF_IS_SYMBOLIC | flags;
121 	(*ref)->ref.symref.name = strdup(name);
122 	if ((*ref)->ref.symref.name == NULL) {
123 		err = got_error_from_errno("strdup");
124 		got_ref_close(*ref);
125 		*ref = NULL;
126 		return err;
127 	}
128 	(*ref)->ref.symref.ref = strdup(target_ref);
129 	if ((*ref)->ref.symref.ref == NULL) {
130 		err = got_error_from_errno("strdup");
131 		got_ref_close(*ref);
132 		*ref = NULL;
133 	}
134 	return err;
135 }
136 
137 static const struct got_error *
138 parse_symref(struct got_reference **ref, const char *name, const char *line)
139 {
140 	if (line[0] == '\0')
141 		return got_error(GOT_ERR_BAD_REF_DATA);
142 
143 	return alloc_symref(ref, name, line, 0);
144 }
145 
146 static const struct got_error *
147 parse_ref_line(struct got_reference **ref, const char *name, const char *line)
148 {
149 	struct got_object_id id;
150 
151 	if (strncmp(line, "ref: ", 5) == 0) {
152 		line += 5;
153 		return parse_symref(ref, name, line);
154 	}
155 
156 	if (!got_parse_sha1_digest(id.sha1, line))
157 		return got_error(GOT_ERR_BAD_REF_DATA);
158 
159 	return alloc_ref(ref, name, &id, 0);
160 }
161 
162 static const struct got_error *
163 parse_ref_file(struct got_reference **ref, const char *name,
164     const char *abspath, int lock)
165 {
166 	const struct got_error *err = NULL;
167 	FILE *f;
168 	char *line = NULL;
169 	size_t linesize = 0;
170 	ssize_t linelen;
171 	struct got_lockfile *lf = NULL;
172 
173 	if (lock) {
174 		err = got_lockfile_lock(&lf, abspath);
175 		if (err)
176 			return (err);
177 	}
178 
179 	f = fopen(abspath, "rb");
180 	if (f == NULL) {
181 		if (lock)
182 			got_lockfile_unlock(lf);
183 		return NULL;
184 	}
185 
186 	linelen = getline(&line, &linesize, f);
187 	if (linelen == -1) {
188 		if (feof(f))
189 			err = NULL; /* ignore empty files (could be locks) */
190 		else
191 			err = got_error_from_errno2("getline", abspath);
192 		if (lock)
193 			got_lockfile_unlock(lf);
194 		goto done;
195 	}
196 	while (linelen > 0 && line[linelen - 1] == '\n') {
197 		line[linelen - 1] = '\0';
198 		linelen--;
199 	}
200 
201 	err = parse_ref_line(ref, name, line);
202 	if (lock) {
203 		if (err)
204 			got_lockfile_unlock(lf);
205 		else {
206 			if (*ref)
207 				(*ref)->lf = lf;
208 			else
209 				got_lockfile_unlock(lf);
210 		}
211 	}
212 done:
213 	free(line);
214 	if (fclose(f) != 0 && err == NULL) {
215 		err = got_error_from_errno("fclose");
216 		if (*ref) {
217 			if (lock)
218 				got_ref_unlock(*ref);
219 			got_ref_close(*ref);
220 			*ref = NULL;
221 		}
222 	}
223 	return err;
224 }
225 
226 static int
227 is_well_known_ref(const char *refname)
228 {
229 	return (strcmp(refname, GOT_REF_HEAD) == 0 ||
230 	    strcmp(refname, GOT_REF_ORIG_HEAD) == 0 ||
231 	    strcmp(refname, GOT_REF_MERGE_HEAD) == 0 ||
232 	    strcmp(refname, GOT_REF_FETCH_HEAD) == 0);
233 }
234 
235 static char *
236 get_refs_dir_path(struct got_repository *repo, const char *refname)
237 {
238 	if (is_well_known_ref(refname) || strncmp(refname, "refs/", 5) == 0)
239 		return strdup(got_repo_get_path_git_dir(repo));
240 
241 	return got_repo_get_path_refs(repo);
242 }
243 
244 static int
245 is_valid_ref_name(const char *name)
246 {
247 	const char *s, *slash, *seg;
248 	const char forbidden[] = { ' ', '~', '^', ':', '?', '*', '[' , '\\' };
249 	const char *forbidden_seq[] = { "//", "..", "@{" };
250 	const char *lfs = GOT_LOCKFILE_SUFFIX;
251 	const size_t lfs_len = sizeof(GOT_LOCKFILE_SUFFIX) - 1;
252 	int i;
253 
254 	if (name[0] == '@' && name[1] == '\0')
255 		return 0;
256 
257 	slash = strchr(name, '/');
258 	if (slash == NULL)
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 static const struct got_error *
675 insert_ref(struct got_reflist_entry **newp, struct got_reflist_head *refs,
676     struct got_reference *ref, struct got_repository *repo,
677     got_ref_cmp_cb cmp_cb, void *cmp_arg)
678 {
679 	const struct got_error *err;
680 	struct got_object_id *id;
681 	struct got_reflist_entry *new, *re, *prev = NULL;
682 	int cmp;
683 
684 	*newp = NULL;
685 
686 	err = got_ref_resolve(&id, repo, ref);
687 	if (err)
688 		return err;
689 
690 	new = malloc(sizeof(*new));
691 	if (new == NULL) {
692 		free(id);
693 		return got_error_from_errno("malloc");
694 	}
695 	new->ref = ref;
696 	new->id = id;
697 	*newp = new;
698 
699 	/*
700 	 * We must de-duplicate entries on insert because packed-refs may
701 	 * contain redundant entries. On-disk refs take precedence.
702 	 * This code assumes that on-disk revs are read before packed-refs.
703 	 * We're iterating the list anyway, so insert elements sorted by name.
704 	 */
705 	re = SIMPLEQ_FIRST(refs);
706 	while (re) {
707 		err = (*cmp_cb)(cmp_arg, &cmp, re->ref, new->ref);
708 		if (err)
709 			return err;
710 		if (cmp == 0) {
711 			/* duplicate */
712 			free(new->id);
713 			free(new);
714 			*newp = NULL;
715 			return NULL;
716 		} else if (cmp > 0) {
717 			if (prev)
718 				SIMPLEQ_INSERT_AFTER(refs, prev, new, entry);
719 			else
720 				SIMPLEQ_INSERT_HEAD(refs, new, entry);
721 			return NULL;
722 		} else {
723 			prev = re;
724 			re = SIMPLEQ_NEXT(re, entry);
725 		}
726 	}
727 
728 	SIMPLEQ_INSERT_TAIL(refs, new, entry);
729 	return NULL;
730 }
731 
732 static const struct got_error *
733 gather_on_disk_refs(struct got_reflist_head *refs, const char *path_refs,
734     const char *subdir, struct got_repository *repo,
735     got_ref_cmp_cb cmp_cb, void *cmp_arg)
736 {
737 	const struct got_error *err = NULL;
738 	DIR *d = NULL;
739 	char *path_subdir;
740 
741 	if (asprintf(&path_subdir, "%s/%s", path_refs, subdir) == -1)
742 		return got_error_from_errno("asprintf");
743 
744 	d = opendir(path_subdir);
745 	if (d == NULL)
746 		goto done;
747 
748 	for (;;) {
749 		struct dirent *dent;
750 		struct got_reference *ref;
751 		char *child;
752 
753 		dent = readdir(d);
754 		if (dent == NULL)
755 			break;
756 
757 		if (strcmp(dent->d_name, ".") == 0 ||
758 		    strcmp(dent->d_name, "..") == 0)
759 			continue;
760 
761 		switch (dent->d_type) {
762 		case DT_REG:
763 			err = open_ref(&ref, path_refs, subdir, dent->d_name,
764 			    0);
765 			if (err)
766 				goto done;
767 			if (ref) {
768 				struct got_reflist_entry *new;
769 				err = insert_ref(&new, refs, ref, repo,
770 				    cmp_cb, cmp_arg);
771 				if (err || new == NULL /* duplicate */)
772 					got_ref_close(ref);
773 				if (err)
774 					goto done;
775 			}
776 			break;
777 		case DT_DIR:
778 			if (asprintf(&child, "%s%s%s", subdir,
779 			    subdir[0] == '\0' ? "" : "/", dent->d_name) == -1) {
780 				err = got_error_from_errno("asprintf");
781 				break;
782 			}
783 			err = gather_on_disk_refs(refs, path_refs, child, repo,
784 			    cmp_cb, cmp_arg);
785 			free(child);
786 			break;
787 		default:
788 			break;
789 		}
790 	}
791 done:
792 	if (d)
793 		closedir(d);
794 	free(path_subdir);
795 	return err;
796 }
797 
798 const struct got_error *
799 got_ref_list(struct got_reflist_head *refs, struct got_repository *repo,
800     const char *ref_namespace, got_ref_cmp_cb cmp_cb, void *cmp_arg)
801 {
802 	const struct got_error *err;
803 	char *packed_refs_path, *path_refs = NULL;
804 	const char *ondisk_ref_namespace = NULL;
805 	FILE *f = NULL;
806 	struct got_reference *ref;
807 	struct got_reflist_entry *new;
808 
809 	if (ref_namespace == NULL || ref_namespace[0] == '\0') {
810 		/* HEAD ref should always exist. */
811 		path_refs = get_refs_dir_path(repo, GOT_REF_HEAD);
812 		if (path_refs == NULL) {
813 			err = got_error_from_errno("get_refs_dir_path");
814 			goto done;
815 		}
816 		err = open_ref(&ref, path_refs, "", GOT_REF_HEAD, 0);
817 		if (err)
818 			goto done;
819 		err = insert_ref(&new, refs, ref, repo, cmp_cb, cmp_arg);
820 		if (err || new == NULL /* duplicate */)
821 			got_ref_close(ref);
822 		if (err)
823 			goto done;
824 	}
825 
826 	ondisk_ref_namespace = ref_namespace;
827 	if (ref_namespace && strncmp(ref_namespace, "refs/", 5) == 0)
828 		ondisk_ref_namespace += 5;
829 
830 	/* Gather on-disk refs before parsing packed-refs. */
831 	free(path_refs);
832 	path_refs = get_refs_dir_path(repo, "");
833 	if (path_refs == NULL) {
834 		err = got_error_from_errno("get_refs_dir_path");
835 		goto done;
836 	}
837 	err = gather_on_disk_refs(refs, path_refs,
838 	    ondisk_ref_namespace ? ondisk_ref_namespace : "", repo,
839 	    cmp_cb, cmp_arg);
840 	if (err)
841 		goto done;
842 
843 	/*
844 	 * The packed-refs file may contain redundant entries, in which
845 	 * case on-disk refs take precedence.
846 	 */
847 	packed_refs_path = got_repo_get_path_packed_refs(repo);
848 	if (packed_refs_path == NULL) {
849 		err = got_error_from_errno("got_repo_get_path_packed_refs");
850 		goto done;
851 	}
852 
853 	f = fopen(packed_refs_path, "r");
854 	free(packed_refs_path);
855 	if (f) {
856 		char *line;
857 		size_t len;
858 		const char delim[3] = {'\0', '\0', '\0'};
859 		for (;;) {
860 			line = fparseln(f, &len, NULL, delim, 0);
861 			if (line == NULL) {
862 				if (feof(f))
863 					break;
864 				err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
865 				goto done;
866 			}
867 			err = parse_packed_ref_line(&ref, NULL, line);
868 			free(line);
869 			if (err)
870 				goto done;
871 			if (ref) {
872 				if (ref_namespace) {
873 					const char *name;
874 					name = got_ref_get_name(ref);
875 					if (strncmp(name, ref_namespace,
876 					    strlen(ref_namespace)) != 0) {
877 						got_ref_close(ref);
878 						continue;
879 					}
880 				}
881 				err = insert_ref(&new, refs, ref, repo,
882 				    cmp_cb, cmp_arg);
883 				if (err || new == NULL /* duplicate */)
884 					got_ref_close(ref);
885 				if (err)
886 					goto done;
887 			}
888 		}
889 	}
890 done:
891 	free(path_refs);
892 	if (f && fclose(f) != 0 && err == NULL)
893 		err = got_error_from_errno("fclose");
894 	return err;
895 }
896 
897 void
898 got_ref_list_free(struct got_reflist_head *refs)
899 {
900 	struct got_reflist_entry *re;
901 
902 	while (!SIMPLEQ_EMPTY(refs)) {
903 		re = SIMPLEQ_FIRST(refs);
904 		SIMPLEQ_REMOVE_HEAD(refs, entry);
905 		got_ref_close(re->ref);
906 		free(re->id);
907 		free(re);
908 	}
909 
910 }
911 
912 int
913 got_ref_is_symbolic(struct got_reference *ref)
914 {
915 	return (ref->flags & GOT_REF_IS_SYMBOLIC);
916 }
917 
918 const struct got_error *
919 got_ref_change_ref(struct got_reference *ref, struct got_object_id *id)
920 {
921 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
922 		return got_error(GOT_ERR_BAD_REF_TYPE);
923 
924 	memcpy(ref->ref.ref.sha1, id->sha1, sizeof(ref->ref.ref.sha1));
925 	return NULL;
926 }
927 
928 const struct got_error *
929 got_ref_change_symref(struct got_reference *ref, char *refname)
930 {
931 	char *new_name;
932 
933 	if ((ref->flags & GOT_REF_IS_SYMBOLIC) == 0)
934 		return got_error(GOT_ERR_BAD_REF_TYPE);
935 
936 	new_name = strdup(refname);
937 	if (new_name == NULL)
938 		return got_error_from_errno("strdup");
939 
940 	free(ref->ref.symref.name);
941 	ref->ref.symref.name = new_name;
942 	return NULL;
943 }
944 
945 const struct got_error *
946 got_ref_write(struct got_reference *ref, struct got_repository *repo)
947 {
948 	const struct got_error *err = NULL, *unlock_err = NULL;
949 	const char *name = got_ref_get_name(ref);
950 	char *path_refs = NULL, *path = NULL, *tmppath = NULL;
951 	struct got_lockfile *lf = NULL;
952 	FILE *f = NULL;
953 	size_t n;
954 	struct stat sb;
955 
956 	path_refs = get_refs_dir_path(repo, name);
957 	if (path_refs == NULL) {
958 		err = got_error_from_errno2("get_refs_dir_path", name);
959 		goto done;
960 	}
961 
962 	if (asprintf(&path, "%s/%s", path_refs, name) == -1) {
963 		err = got_error_from_errno("asprintf");
964 		goto done;
965 	}
966 
967 	err = got_opentemp_named(&tmppath, &f, path);
968 	if (err) {
969 		char *parent;
970 		if (!(err->code == GOT_ERR_ERRNO && errno == ENOENT))
971 			goto done;
972 		err = got_path_dirname(&parent, path);
973 		if (err)
974 			goto done;
975 		err = got_path_mkdir(parent);
976 		free(parent);
977 		if (err)
978 			goto done;
979 		err = got_opentemp_named(&tmppath, &f, path);
980 		if (err)
981 			goto done;
982 	}
983 
984 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
985 		n = fprintf(f, "ref: %s\n", ref->ref.symref.ref);
986 		if (n != strlen(ref->ref.symref.ref) + 6) {
987 			err = got_ferror(f, GOT_ERR_IO);
988 			goto done;
989 		}
990 	} else {
991 		char hex[SHA1_DIGEST_STRING_LENGTH];
992 		if (got_sha1_digest_to_str(ref->ref.ref.sha1, hex,
993 		    sizeof(hex)) == NULL) {
994 			err = got_error(GOT_ERR_BAD_REF_DATA);
995 			goto done;
996 		}
997 		n = fprintf(f, "%s\n", hex);
998 		if (n != sizeof(hex)) {
999 			err = got_ferror(f, GOT_ERR_IO);
1000 			goto done;
1001 		}
1002 	}
1003 
1004 	if (ref->lf == NULL) {
1005 		err = got_lockfile_lock(&lf, path);
1006 		if (err)
1007 			goto done;
1008 	}
1009 
1010 	/* XXX: check if old content matches our expectations? */
1011 
1012 	if (stat(path, &sb) != 0) {
1013 		if (errno != ENOENT) {
1014 			err = got_error_from_errno2("stat", path);
1015 			goto done;
1016 		}
1017 		sb.st_mode = GOT_DEFAULT_FILE_MODE;
1018 	}
1019 
1020 	if (rename(tmppath, path) != 0) {
1021 		err = got_error_from_errno3("rename", tmppath, path);
1022 		goto done;
1023 	}
1024 	free(tmppath);
1025 	tmppath = NULL;
1026 
1027 	if (chmod(path, sb.st_mode) != 0) {
1028 		err = got_error_from_errno2("chmod", path);
1029 		goto done;
1030 	}
1031 done:
1032 	if (ref->lf == NULL && lf)
1033 		unlock_err = got_lockfile_unlock(lf);
1034 	if (f) {
1035 		if (fclose(f) != 0 && err == NULL)
1036 			err = got_error_from_errno("fclose");
1037 	}
1038 	free(path_refs);
1039 	free(path);
1040 	if (tmppath) {
1041 		if (unlink(tmppath) != 0 && err == NULL)
1042 			err = got_error_from_errno2("unlink", tmppath);
1043 		free(tmppath);
1044 	}
1045 	return err ? err : unlock_err;
1046 }
1047 
1048 static const struct got_error *
1049 delete_packed_ref(struct got_reference *delref, struct got_repository *repo)
1050 {
1051 	const struct got_error *err = NULL, *unlock_err = NULL;
1052 	struct got_lockfile *lf = NULL;
1053 	FILE *f = NULL, *tmpf = NULL;
1054 	char *packed_refs_path, *tmppath = NULL;
1055 	struct got_reflist_head refs;
1056 	int found_delref = 0;
1057 
1058 	/* The packed-refs file does not cotain symbolic references. */
1059 	if (delref->flags & GOT_REF_IS_SYMBOLIC)
1060 		return got_error(GOT_ERR_BAD_REF_DATA);
1061 
1062 	SIMPLEQ_INIT(&refs);
1063 
1064 	packed_refs_path = got_repo_get_path_packed_refs(repo);
1065 	if (packed_refs_path == NULL)
1066 		return got_error_from_errno("got_repo_get_path_packed_refs");
1067 
1068 	err = got_opentemp_named(&tmppath, &tmpf, packed_refs_path);
1069 	if (err)
1070 		goto done;
1071 
1072 	if (delref->lf == NULL) {
1073 		err = got_lockfile_lock(&lf, packed_refs_path);
1074 		if (err)
1075 			goto done;
1076 	}
1077 
1078 	f = fopen(packed_refs_path, "r");
1079 	if (f == NULL) {
1080 		err = got_error_from_errno2("fopen", packed_refs_path);
1081 		goto done;
1082 	}
1083 	for (;;) {
1084 		char *line;
1085 		size_t len;
1086 		const char delim[3] = {'\0', '\0', '\0'};
1087 		struct got_reference *ref;
1088 		struct got_reflist_entry *new;
1089 
1090 		line = fparseln(f, &len, NULL, delim, 0);
1091 		if (line == NULL) {
1092 			if (feof(f))
1093 				break;
1094 			err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
1095 			goto done;
1096 		}
1097 		err = parse_packed_ref_line(&ref, NULL, line);
1098 		free(line);
1099 		if (err)
1100 			goto done;
1101 		if (ref == NULL)
1102 			continue;
1103 
1104 		if (strcmp(ref->ref.ref.name, delref->ref.ref.name) == 0 &&
1105 		    memcmp(ref->ref.ref.sha1, delref->ref.ref.sha1,
1106 		    sizeof(delref->ref.ref.sha1)) == 0) {
1107 			found_delref = 1;
1108 			got_ref_close(ref);
1109 			continue;
1110 		}
1111 
1112 		err = insert_ref(&new, &refs, ref, repo,
1113 		    got_ref_cmp_by_name, NULL);
1114 		if (err || new == NULL /* duplicate */)
1115 			got_ref_close(ref);
1116 		if (err)
1117 			goto done;
1118 	}
1119 
1120 	if (found_delref) {
1121 		struct got_reflist_entry *re;
1122 		size_t n;
1123 		struct stat sb;
1124 
1125 		n = fprintf(tmpf, "%s\n", GOT_PACKED_REFS_HEADER);
1126 		if (n != sizeof(GOT_PACKED_REFS_HEADER)) {
1127 			err = got_ferror(f, GOT_ERR_IO);
1128 			goto done;
1129 		}
1130 
1131 		SIMPLEQ_FOREACH(re, &refs, entry) {
1132 			uint8_t hex[SHA1_DIGEST_STRING_LENGTH];
1133 
1134 			if (got_sha1_digest_to_str(re->ref->ref.ref.sha1, hex,
1135 			    sizeof(hex)) == NULL) {
1136 				err = got_error(GOT_ERR_BAD_REF_DATA);
1137 				goto done;
1138 			}
1139 			n = fprintf(tmpf, "%s ", hex);
1140 			if (n != sizeof(hex)) {
1141 				err = got_ferror(f, GOT_ERR_IO);
1142 				goto done;
1143 			}
1144 			n = fprintf(tmpf, "%s\n", re->ref->ref.ref.name);
1145 			if (n != strlen(re->ref->ref.ref.name) + 1) {
1146 				err = got_ferror(f, GOT_ERR_IO);
1147 				goto done;
1148 			}
1149 		}
1150 
1151 		if (fflush(tmpf) != 0) {
1152 			err = got_error_from_errno("fflush");
1153 			goto done;
1154 		}
1155 
1156 		if (stat(packed_refs_path, &sb) != 0) {
1157 			if (errno != ENOENT) {
1158 				err = got_error_from_errno2("stat",
1159 				    packed_refs_path);
1160 				goto done;
1161 			}
1162 			sb.st_mode = GOT_DEFAULT_FILE_MODE;
1163 		}
1164 
1165 		if (rename(tmppath, packed_refs_path) != 0) {
1166 			err = got_error_from_errno3("rename", tmppath,
1167 			    packed_refs_path);
1168 			goto done;
1169 		}
1170 
1171 		if (chmod(packed_refs_path, sb.st_mode) != 0) {
1172 			err = got_error_from_errno2("chmod",
1173 			    packed_refs_path);
1174 			goto done;
1175 		}
1176 	}
1177 done:
1178 	if (delref->lf == NULL && lf)
1179 		unlock_err = got_lockfile_unlock(lf);
1180 	if (f) {
1181 		if (fclose(f) != 0 && err == NULL)
1182 			err = got_error_from_errno("fclose");
1183 	}
1184 	if (tmpf) {
1185 		unlink(tmppath);
1186 		if (fclose(tmpf) != 0 && err == NULL)
1187 			err = got_error_from_errno("fclose");
1188 	}
1189 	free(tmppath);
1190 	free(packed_refs_path);
1191 	got_ref_list_free(&refs);
1192 	return err ? err : unlock_err;
1193 }
1194 
1195 const struct got_error *
1196 got_ref_delete(struct got_reference *ref, struct got_repository *repo)
1197 {
1198 	const struct got_error *err = NULL, *unlock_err = NULL;
1199 	const char *name = got_ref_get_name(ref);
1200 	char *path_refs = NULL, *path = NULL;
1201 	struct got_lockfile *lf = NULL;
1202 
1203 	if (ref->flags & GOT_REF_IS_PACKED)
1204 		return delete_packed_ref(ref, repo);
1205 
1206 	path_refs = get_refs_dir_path(repo, name);
1207 	if (path_refs == NULL) {
1208 		err = got_error_from_errno2("get_refs_dir_path", name);
1209 		goto done;
1210 	}
1211 
1212 	if (asprintf(&path, "%s/%s", path_refs, name) == -1) {
1213 		err = got_error_from_errno("asprintf");
1214 		goto done;
1215 	}
1216 
1217 	if (ref->lf == NULL) {
1218 		err = got_lockfile_lock(&lf, path);
1219 		if (err)
1220 			goto done;
1221 	}
1222 
1223 	/* XXX: check if old content matches our expectations? */
1224 
1225 	if (unlink(path) != 0)
1226 		err = got_error_from_errno2("unlink", path);
1227 done:
1228 	if (ref->lf == NULL && lf)
1229 		unlock_err = got_lockfile_unlock(lf);
1230 
1231 	free(path_refs);
1232 	free(path);
1233 	return err ? err : unlock_err;
1234 }
1235 
1236 const struct got_error *
1237 got_ref_unlock(struct got_reference *ref)
1238 {
1239 	const struct got_error *err;
1240 	err = got_lockfile_unlock(ref->lf);
1241 	ref->lf = NULL;
1242 	return err;
1243 }