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Date:: Mon Aug 12 22:32:42 2019 UTC
Message:: introuce a hard limit on recursion through symbolic references
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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 	}
127 	(*ref)->ref.symref.ref = strdup(target_ref);
128 	if ((*ref)->ref.symref.ref == NULL) {
129 		err = got_error_from_errno("strdup");
130 		got_ref_close(*ref);
131 		*ref = NULL;
132 	}
133 	return err;
134 }
135 
136 static const struct got_error *
137 parse_symref(struct got_reference **ref, const char *name, const char *line)
138 {
139 	if (line[0] == '\0')
140 		return got_error(GOT_ERR_BAD_REF_DATA);
141 
142 	return alloc_symref(ref, name, line, 0);
143 }
144 
145 static const struct got_error *
146 parse_ref_line(struct got_reference **ref, const char *name, const char *line)
147 {
148 	struct got_object_id id;
149 
150 	if (strncmp(line, "ref: ", 5) == 0) {
151 		line += 5;
152 		return parse_symref(ref, name, line);
153 	}
154 
155 	if (!got_parse_sha1_digest(id.sha1, line))
156 		return got_error(GOT_ERR_BAD_REF_DATA);
157 
158 	return alloc_ref(ref, name, &id, 0);
159 }
160 
161 static const struct got_error *
162 parse_ref_file(struct got_reference **ref, const char *name,
163     const char *abspath, int lock)
164 {
165 	const struct got_error *err = NULL;
166 	FILE *f;
167 	char *line;
168 	size_t len;
169 	const char delim[3] = {'\0', '\0', '\0'};
170 	struct got_lockfile *lf = NULL;
171 
172 	if (lock) {
173 		err = got_lockfile_lock(&lf, abspath);
174 		if (err)
175 			return (err);
176 	}
177 
178 	f = fopen(abspath, "rb");
179 	if (f == NULL) {
180 		if (lock)
181 			got_lockfile_unlock(lf);
182 		return NULL;
183 	}
184 
185 	line = fparseln(f, &len, NULL, delim, 0);
186 	if (line == NULL) {
187 		err = got_error(GOT_ERR_BAD_REF_DATA);
188 		if (lock)
189 			got_lockfile_unlock(lf);
190 		goto done;
191 	}
192 
193 	err = parse_ref_line(ref, name, line);
194 	if (lock) {
195 		if (err)
196 			got_lockfile_unlock(lf);
197 		else {
198 			if (*ref)
199 				(*ref)->lf = lf;
200 			else
201 				got_lockfile_unlock(lf);
202 		}
203 	}
204 done:
205 	free(line);
206 	if (fclose(f) != 0 && err == NULL) {
207 		err = got_error_from_errno("fclose");
208 		if (*ref) {
209 			if (lock)
210 				got_ref_unlock(*ref);
211 			got_ref_close(*ref);
212 			*ref = NULL;
213 		}
214 	}
215 	return err;
216 }
217 
218 static int
219 is_well_known_ref(const char *refname)
220 {
221 	return (strcmp(refname, GOT_REF_HEAD) == 0 ||
222 	    strcmp(refname, GOT_REF_ORIG_HEAD) == 0 ||
223 	    strcmp(refname, GOT_REF_MERGE_HEAD) == 0 ||
224 	    strcmp(refname, GOT_REF_FETCH_HEAD) == 0);
225 }
226 
227 static char *
228 get_refs_dir_path(struct got_repository *repo, const char *refname)
229 {
230 	if (is_well_known_ref(refname) || strncmp(refname, "refs/", 5) == 0)
231 		return strdup(got_repo_get_path_git_dir(repo));
232 
233 	return got_repo_get_path_refs(repo);
234 }
235 
236 static int
237 is_valid_ref_name(const char *name)
238 {
239 	const char *s, *slash, *seg;
240 	const char forbidden[] = { ' ', '~', '^', ':', '?', '*', '[' , '\\' };
241 	const char *forbidden_seq[] = { "//", "..", "@{" };
242 	const char *lfs = GOT_LOCKFILE_SUFFIX;
243 	const size_t lfs_len = sizeof(GOT_LOCKFILE_SUFFIX) - 1;
244 	int i;
245 
246 	if (name[0] == '@' && name[1] == '\0')
247 		return 0;
248 
249 	slash = strchr(name, '/');
250 	if (slash == NULL)
251 		return 0;
252 
253 	s = name;
254 	seg = s;
255 	if (seg[0] == '\0' || seg[0] == '.' || seg[0] == '/')
256 		return 0;
257 	while (*s) {
258 		for (i = 0; i < nitems(forbidden); i++) {
259 			if (*s == forbidden[i])
260 				return 0;
261 		}
262 		for (i = 0; i < nitems(forbidden_seq); i++) {
263 			if (s[0] == forbidden_seq[i][0] &&
264 			    s[1] == forbidden_seq[i][1])
265 				return 0;
266 		}
267 		if (iscntrl((unsigned char)s[0]))
268 			return 0;
269 		if (s[0] == '.' && s[1] == '\0')
270 			return 0;
271 		if (*s == '/') {
272 			const char *nextseg = s + 1;
273 			if (nextseg[0] == '\0' || nextseg[0] == '.' ||
274 			    nextseg[0] == '/')
275 				return 0;
276 			if (seg <= s - lfs_len &&
277 			    strncmp(s - lfs_len, lfs, lfs_len) == 0)
278 				return 0;
279 			seg = nextseg;
280 		}
281 		s++;
282 	}
283 
284 	if (seg <= s - lfs_len &&
285 	    strncmp(s - lfs_len, lfs, lfs_len) == 0)
286 		return 0;
287 
288 	return 1;
289 }
290 
291 const struct got_error *
292 got_ref_alloc(struct got_reference **ref, const char *name,
293     struct got_object_id *id)
294 {
295 	if (!is_valid_ref_name(name))
296 		return got_error(GOT_ERR_BAD_REF_NAME);
297 
298 	return alloc_ref(ref, name, id, 0);
299 }
300 
301 const struct got_error *
302 got_ref_alloc_symref(struct got_reference **ref, const char *name,
303 	struct got_reference *target_ref)
304 {
305 	if (!is_valid_ref_name(name))
306 		return got_error(GOT_ERR_BAD_REF_NAME);
307 
308 	return alloc_symref(ref, name, got_ref_get_name(target_ref), 0);
309 }
310 
311 static const struct got_error *
312 parse_packed_ref_line(struct got_reference **ref, const char *abs_refname,
313     const char *line)
314 {
315 	struct got_object_id id;
316 	const char *name;
317 
318 	*ref = NULL;
319 
320 	if (line[0] == '#' || line[0] == '^')
321 		return NULL;
322 
323 	if (!got_parse_sha1_digest(id.sha1, line))
324 		return got_error(GOT_ERR_BAD_REF_DATA);
325 
326 	if (abs_refname) {
327 		if (strcmp(line + SHA1_DIGEST_STRING_LENGTH, abs_refname) != 0)
328 			return NULL;
329 		name = abs_refname;
330 	} else
331 		name = line + SHA1_DIGEST_STRING_LENGTH;
332 
333 	return alloc_ref(ref, name, &id, GOT_REF_IS_PACKED);
334 }
335 
336 static const struct got_error *
337 open_packed_ref(struct got_reference **ref, FILE *f, const char **subdirs,
338     int nsubdirs, const char *refname)
339 {
340 	const struct got_error *err = NULL;
341 	char *abs_refname;
342 	char *line;
343 	size_t len;
344 	const char delim[3] = {'\0', '\0', '\0'};
345 	int i, ref_is_absolute = (strncmp(refname, "refs/", 5) == 0);
346 
347 	*ref = NULL;
348 
349 	if (ref_is_absolute)
350 		abs_refname = (char *)refname;
351 	do {
352 		line = fparseln(f, &len, NULL, delim, 0);
353 		if (line == NULL) {
354 			if (feof(f))
355 				break;
356 			err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
357 			break;
358 		}
359 		for (i = 0; i < nsubdirs; i++) {
360 			if (!ref_is_absolute &&
361 			    asprintf(&abs_refname, "refs/%s/%s", subdirs[i],
362 			    refname) == -1)
363 				return got_error_from_errno("asprintf");
364 			err = parse_packed_ref_line(ref, abs_refname, line);
365 			if (!ref_is_absolute)
366 				free(abs_refname);
367 			if (err || *ref != NULL)
368 				break;
369 		}
370 		free(line);
371 		if (err)
372 			break;
373 	} while (*ref == NULL);
374 
375 	return err;
376 }
377 
378 static const struct got_error *
379 open_ref(struct got_reference **ref, const char *path_refs, const char *subdir,
380     const char *name, int lock)
381 {
382 	const struct got_error *err = NULL;
383 	char *path = NULL;
384 	char *absname = NULL;
385 	int ref_is_absolute = (strncmp(name, "refs/", 5) == 0);
386 	int ref_is_well_known = is_well_known_ref(name);
387 
388 	*ref = NULL;
389 
390 	if (ref_is_absolute || ref_is_well_known) {
391 		if (asprintf(&path, "%s/%s", path_refs, name) == -1)
392 			return got_error_from_errno("asprintf");
393 		absname = (char *)name;
394 	} else {
395 		if (asprintf(&path, "%s/%s%s%s", path_refs, subdir,
396 		    subdir[0] ? "/" : "", name) == -1)
397 			return got_error_from_errno("asprintf");
398 
399 		if (asprintf(&absname, "refs/%s%s%s",
400 		    subdir, subdir[0] ? "/" : "", name) == -1) {
401 			err = got_error_from_errno("asprintf");
402 			goto done;
403 		}
404 	}
405 
406 	err = parse_ref_file(ref, absname, path, lock);
407 done:
408 	if (!ref_is_absolute && !ref_is_well_known)
409 		free(absname);
410 	free(path);
411 	return err;
412 }
413 
414 const struct got_error *
415 got_ref_open(struct got_reference **ref, struct got_repository *repo,
416    const char *refname, int lock)
417 {
418 	const struct got_error *err = NULL;
419 	char *path_refs = NULL;
420 	const char *subdirs[] = {
421 	    GOT_REF_HEADS, GOT_REF_TAGS, GOT_REF_REMOTES
422 	};
423 	int i, well_known = is_well_known_ref(refname);
424 	struct got_lockfile *lf = NULL;
425 
426 	*ref = NULL;
427 
428 	path_refs = get_refs_dir_path(repo, refname);
429 	if (path_refs == NULL) {
430 		err = got_error_from_errno2("get_refs_dir_path", refname);
431 		goto done;
432 	}
433 
434 	if (well_known) {
435 		err = open_ref(ref, path_refs, "", refname, lock);
436 	} else {
437 		char *packed_refs_path;
438 		FILE *f;
439 
440 		/* Search on-disk refs before packed refs! */
441 		for (i = 0; i < nitems(subdirs); i++) {
442 			err = open_ref(ref, path_refs, subdirs[i], refname,
443 			    lock);
444 			if (err || *ref)
445 				goto done;
446 		}
447 
448 		packed_refs_path = got_repo_get_path_packed_refs(repo);
449 		if (packed_refs_path == NULL) {
450 			err = got_error_from_errno(
451 			    "got_repo_get_path_packed_refs");
452 			goto done;
453 		}
454 
455 		if (lock) {
456 			err = got_lockfile_lock(&lf, packed_refs_path);
457 			if (err)
458 				goto done;
459 		}
460 		f = fopen(packed_refs_path, "rb");
461 		free(packed_refs_path);
462 		if (f != NULL) {
463 			err = open_packed_ref(ref, f, subdirs, nitems(subdirs),
464 			    refname);
465 			if (!err) {
466 				if (fclose(f) != 0) {
467 					err = got_error_from_errno("fclose");
468 					got_ref_close(*ref);
469 					*ref = NULL;
470 				} else if (*ref)
471 					(*ref)->lf = lf;
472 			}
473 		}
474 	}
475 done:
476 	if (!err && *ref == NULL)
477 		err = got_error_not_ref(refname);
478 	if (err && lf)
479 		got_lockfile_unlock(lf);
480 	free(path_refs);
481 	return err;
482 }
483 
484 void
485 got_ref_close(struct got_reference *ref)
486 {
487 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
488 		free(ref->ref.symref.name);
489 		free(ref->ref.symref.ref);
490 	} else
491 		free(ref->ref.ref.name);
492 	free(ref);
493 }
494 
495 struct got_reference *
496 got_ref_dup(struct got_reference *ref)
497 {
498 	struct got_reference *ret;
499 
500 	ret = calloc(1, sizeof(*ret));
501 	if (ret == NULL)
502 		return NULL;
503 
504 	ret->flags = ref->flags;
505 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
506 		ret->ref.symref.name = strdup(ref->ref.symref.name);
507 		if (ret->ref.symref.name == NULL) {
508 			free(ret);
509 			return NULL;
510 		}
511 		ret->ref.symref.ref = strdup(ref->ref.symref.ref);
512 		if (ret->ref.symref.ref == NULL) {
513 			free(ret->ref.symref.name);
514 			free(ret);
515 			return NULL;
516 		}
517 	} else {
518 		ref->ref.ref.name = strdup(ref->ref.ref.name);
519 		if (ref->ref.ref.name == NULL) {
520 			free(ret);
521 			return NULL;
522 		}
523 		memcpy(ret->ref.ref.sha1, ref->ref.ref.sha1,
524 		    sizeof(ret->ref.ref.sha1));
525 	}
526 
527 	return ret;
528 }
529 
530 static const struct got_error *
531 resolve_symbolic_ref(struct got_reference **resolved,
532     struct got_repository *repo, struct got_reference *ref)
533 {
534 	struct got_reference *nextref;
535 	const struct got_error *err;
536 
537 	err = got_ref_open(&nextref, repo, ref->ref.symref.ref, 0);
538 	if (err)
539 		return err;
540 
541 	if (nextref->flags & GOT_REF_IS_SYMBOLIC)
542 		err = resolve_symbolic_ref(resolved, repo, nextref);
543 	else
544 		*resolved = got_ref_dup(nextref);
545 
546 	got_ref_close(nextref);
547 	return err;
548 }
549 
550 static const struct got_error *
551 ref_resolve(struct got_object_id **id, struct got_repository *repo,
552     struct got_reference *ref, int recursion)
553 {
554 	const struct got_error *err;
555 
556 	if (recursion <= 0)
557 		return got_error_msg(GOT_ERR_RECURSION,
558 		    "reference recursion limit reached");
559 
560 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
561 		struct got_reference *resolved = NULL;
562 		err = resolve_symbolic_ref(&resolved, repo, ref);
563 		if (err == NULL)
564 			err = ref_resolve(id, repo, resolved, --recursion);
565 		if (resolved)
566 			got_ref_close(resolved);
567 		return err;
568 	}
569 
570 	*id = calloc(1, sizeof(**id));
571 	if (*id == NULL)
572 		return got_error_from_errno("calloc");
573 	memcpy((*id)->sha1, ref->ref.ref.sha1, sizeof((*id)->sha1));
574 	return NULL;
575 }
576 
577 const struct got_error *
578 got_ref_resolve(struct got_object_id **id, struct got_repository *repo,
579     struct got_reference *ref)
580 {
581 	return ref_resolve(id, repo, ref, GOT_REF_RECURSE_MAX);
582 }
583 
584 char *
585 got_ref_to_str(struct got_reference *ref)
586 {
587 	char *str;
588 
589 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
590 		return strdup(ref->ref.symref.ref);
591 
592 	str = malloc(SHA1_DIGEST_STRING_LENGTH);
593 	if (str == NULL)
594 		return NULL;
595 
596 	if (got_sha1_digest_to_str(ref->ref.ref.sha1, str,
597 	    SHA1_DIGEST_STRING_LENGTH) == NULL) {
598 		free(str);
599 		return NULL;
600 	}
601 
602 	return str;
603 }
604 
605 const char *
606 got_ref_get_name(struct got_reference *ref)
607 {
608 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
609 		return ref->ref.symref.name;
610 
611 	return ref->ref.ref.name;
612 }
613 
614 const char *
615 got_ref_get_symref_target(struct got_reference *ref)
616 {
617 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
618 		return ref->ref.symref.ref;
619 
620 	return NULL;
621 }
622 
623 static const struct got_error *
624 insert_ref(struct got_reflist_entry **newp, struct got_reflist_head *refs,
625     struct got_reference *ref, struct got_repository *repo)
626 {
627 	const struct got_error *err;
628 	struct got_object_id *id;
629 	struct got_reflist_entry *new, *re, *prev = NULL;
630 	int cmp;
631 
632 	*newp = NULL;
633 
634 	err = got_ref_resolve(&id, repo, ref);
635 	if (err)
636 		return err;
637 
638 	new = malloc(sizeof(*new));
639 	if (new == NULL) {
640 		free(id);
641 		return got_error_from_errno("malloc");
642 	}
643 	new->ref = ref;
644 	new->id = id;
645 	*newp = new;
646 
647 	/*
648 	 * We must de-duplicate entries on insert because packed-refs may
649 	 * contain redundant entries. On-disk refs take precedence.
650 	 * This code assumes that on-disk revs are read before packed-refs.
651 	 * We're iterating the list anyway, so insert elements sorted by name.
652 	 */
653 	re = SIMPLEQ_FIRST(refs);
654 	while (re) {
655 		const char *name = got_ref_get_name(re->ref);
656 		const char *new_name = got_ref_get_name(new->ref);
657 		cmp = got_path_cmp(name, new_name, strlen(name),
658 		    strlen(new_name));
659 		if (cmp == 0) {
660 			/* duplicate */
661 			free(new->id);
662 			free(new);
663 			*newp = NULL;
664 			return NULL;
665 		} else if (cmp > 0) {
666 			if (prev)
667 				SIMPLEQ_INSERT_AFTER(refs, prev, new, entry);
668 			else
669 				SIMPLEQ_INSERT_HEAD(refs, new, entry);
670 			return NULL;
671 		} else {
672 			prev = re;
673 			re = SIMPLEQ_NEXT(re, entry);
674 		}
675 	}
676 
677 	SIMPLEQ_INSERT_TAIL(refs, new, entry);
678 	return NULL;
679 }
680 
681 static const struct got_error *
682 gather_on_disk_refs(struct got_reflist_head *refs, const char *path_refs,
683     const char *subdir, struct got_repository *repo)
684 {
685 	const struct got_error *err = NULL;
686 	DIR *d = NULL;
687 	char *path_subdir;
688 
689 	if (asprintf(&path_subdir, "%s/%s", path_refs, subdir) == -1)
690 		return got_error_from_errno("asprintf");
691 
692 	d = opendir(path_subdir);
693 	if (d == NULL)
694 		goto done;
695 
696 	for (;;) {
697 		struct dirent *dent;
698 		struct got_reference *ref;
699 		char *child;
700 
701 		dent = readdir(d);
702 		if (dent == NULL)
703 			break;
704 
705 		if (strcmp(dent->d_name, ".") == 0 ||
706 		    strcmp(dent->d_name, "..") == 0)
707 			continue;
708 
709 		switch (dent->d_type) {
710 		case DT_REG:
711 			err = open_ref(&ref, path_refs, subdir, dent->d_name,
712 			    0);
713 			if (err)
714 				goto done;
715 			if (ref) {
716 				struct got_reflist_entry *new;
717 				err = insert_ref(&new, refs, ref, repo);
718 				if (err || new == NULL /* duplicate */)
719 					got_ref_close(ref);
720 				if (err)
721 					goto done;
722 			}
723 			break;
724 		case DT_DIR:
725 			if (asprintf(&child, "%s%s%s", subdir,
726 			    subdir[0] == '\0' ? "" : "/", dent->d_name) == -1) {
727 				err = got_error_from_errno("asprintf");
728 				break;
729 			}
730 			err = gather_on_disk_refs(refs, path_refs, child, repo);
731 			free(child);
732 			break;
733 		default:
734 			break;
735 		}
736 	}
737 done:
738 	if (d)
739 		closedir(d);
740 	free(path_subdir);
741 	return err;
742 }
743 
744 const struct got_error *
745 got_ref_list(struct got_reflist_head *refs, struct got_repository *repo)
746 {
747 	const struct got_error *err;
748 	char *packed_refs_path, *path_refs = NULL;
749 	FILE *f = NULL;
750 	struct got_reference *ref;
751 	struct got_reflist_entry *new;
752 
753 	/* HEAD ref should always exist. */
754 	path_refs = get_refs_dir_path(repo, GOT_REF_HEAD);
755 	if (path_refs == NULL) {
756 		err = got_error_from_errno("get_refs_dir_path");
757 		goto done;
758 	}
759 	err = open_ref(&ref, path_refs, "", GOT_REF_HEAD, 0);
760 	if (err)
761 		goto done;
762 	err = insert_ref(&new, refs, ref, repo);
763 	if (err || new == NULL /* duplicate */)
764 		got_ref_close(ref);
765 	if (err)
766 		goto done;
767 
768 	/* Gather on-disk refs before parsing packed-refs. */
769 	free(path_refs);
770 	path_refs = get_refs_dir_path(repo, "");
771 	if (path_refs == NULL) {
772 		err = got_error_from_errno("get_refs_dir_path");
773 		goto done;
774 	}
775 	err = gather_on_disk_refs(refs, path_refs, "", repo);
776 	if (err)
777 		goto done;
778 
779 	/*
780 	 * The packed-refs file may contain redundant entries, in which
781 	 * case on-disk refs take precedence.
782 	 */
783 	packed_refs_path = got_repo_get_path_packed_refs(repo);
784 	if (packed_refs_path == NULL) {
785 		err = got_error_from_errno("got_repo_get_path_packed_refs");
786 		goto done;
787 	}
788 
789 	f = fopen(packed_refs_path, "r");
790 	free(packed_refs_path);
791 	if (f) {
792 		char *line;
793 		size_t len;
794 		const char delim[3] = {'\0', '\0', '\0'};
795 		for (;;) {
796 			line = fparseln(f, &len, NULL, delim, 0);
797 			if (line == NULL) {
798 				if (feof(f))
799 					break;
800 				err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
801 				goto done;
802 			}
803 			err = parse_packed_ref_line(&ref, NULL, line);
804 			free(line);
805 			if (err)
806 				goto done;
807 			if (ref) {
808 				err = insert_ref(&new, refs, ref, repo);
809 				if (err || new == NULL /* duplicate */)
810 					got_ref_close(ref);
811 				if (err)
812 					goto done;
813 			}
814 		}
815 	}
816 done:
817 	free(path_refs);
818 	if (f && fclose(f) != 0 && err == NULL)
819 		err = got_error_from_errno("fclose");
820 	return err;
821 }
822 
823 void
824 got_ref_list_free(struct got_reflist_head *refs)
825 {
826 	struct got_reflist_entry *re;
827 
828 	while (!SIMPLEQ_EMPTY(refs)) {
829 		re = SIMPLEQ_FIRST(refs);
830 		SIMPLEQ_REMOVE_HEAD(refs, entry);
831 		got_ref_close(re->ref);
832 		free(re->id);
833 		free(re);
834 	}
835 
836 }
837 
838 int
839 got_ref_is_symbolic(struct got_reference *ref)
840 {
841 	return (ref->flags & GOT_REF_IS_SYMBOLIC);
842 }
843 
844 const struct got_error *
845 got_ref_change_ref(struct got_reference *ref, struct got_object_id *id)
846 {
847 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
848 		return got_error(GOT_ERR_BAD_REF_TYPE);
849 
850 	memcpy(ref->ref.ref.sha1, id->sha1, sizeof(ref->ref.ref.sha1));
851 	return NULL;
852 }
853 
854 const struct got_error *
855 got_ref_change_symref(struct got_reference *ref, char *refname)
856 {
857 	char *new_name;
858 
859 	if ((ref->flags & GOT_REF_IS_SYMBOLIC) == 0)
860 		return got_error(GOT_ERR_BAD_REF_TYPE);
861 
862 	new_name = strdup(refname);
863 	if (new_name == NULL)
864 		return got_error_from_errno("strdup");
865 
866 	free(ref->ref.symref.name);
867 	ref->ref.symref.name = new_name;
868 	return NULL;
869 }
870 
871 const struct got_error *
872 got_ref_write(struct got_reference *ref, struct got_repository *repo)
873 {
874 	const struct got_error *err = NULL, *unlock_err = NULL;
875 	const char *name = got_ref_get_name(ref);
876 	char *path_refs = NULL, *path = NULL, *tmppath = NULL;
877 	struct got_lockfile *lf = NULL;
878 	FILE *f = NULL;
879 	size_t n;
880 	struct stat sb;
881 
882 	path_refs = get_refs_dir_path(repo, name);
883 	if (path_refs == NULL) {
884 		err = got_error_from_errno2("get_refs_dir_path", name);
885 		goto done;
886 	}
887 
888 	if (asprintf(&path, "%s/%s", path_refs, name) == -1) {
889 		err = got_error_from_errno("asprintf");
890 		goto done;
891 	}
892 
893 	err = got_opentemp_named(&tmppath, &f, path);
894 	if (err) {
895 		char *parent;
896 		if (!(err->code == GOT_ERR_ERRNO && errno == ENOENT))
897 			goto done;
898 		err = got_path_dirname(&parent, path);
899 		if (err)
900 			goto done;
901 		err = got_path_mkdir(parent);
902 		free(parent);
903 		if (err)
904 			goto done;
905 		err = got_opentemp_named(&tmppath, &f, path);
906 		if (err)
907 			goto done;
908 	}
909 
910 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
911 		n = fprintf(f, "ref: %s\n", ref->ref.symref.ref);
912 		if (n != strlen(ref->ref.symref.ref) + 6) {
913 			err = got_ferror(f, GOT_ERR_IO);
914 			goto done;
915 		}
916 	} else {
917 		char hex[SHA1_DIGEST_STRING_LENGTH];
918 		if (got_sha1_digest_to_str(ref->ref.ref.sha1, hex,
919 		    sizeof(hex)) == NULL) {
920 			err = got_error(GOT_ERR_BAD_REF_DATA);
921 			goto done;
922 		}
923 		n = fprintf(f, "%s\n", hex);
924 		if (n != sizeof(hex)) {
925 			err = got_ferror(f, GOT_ERR_IO);
926 			goto done;
927 		}
928 	}
929 
930 	if (ref->lf == NULL) {
931 		err = got_lockfile_lock(&lf, path);
932 		if (err)
933 			goto done;
934 	}
935 
936 	/* XXX: check if old content matches our expectations? */
937 
938 	if (stat(path, &sb) != 0) {
939 		if (errno != ENOENT) {
940 			err = got_error_from_errno2("stat", path);
941 			goto done;
942 		}
943 		sb.st_mode = GOT_DEFAULT_FILE_MODE;
944 	}
945 
946 	if (rename(tmppath, path) != 0) {
947 		err = got_error_from_errno3("rename", tmppath, path);
948 		goto done;
949 	}
950 	free(tmppath);
951 	tmppath = NULL;
952 
953 	if (chmod(path, sb.st_mode) != 0) {
954 		err = got_error_from_errno2("chmod", path);
955 		goto done;
956 	}
957 done:
958 	if (ref->lf == NULL && lf)
959 		unlock_err = got_lockfile_unlock(lf);
960 	if (f) {
961 		if (fclose(f) != 0 && err == NULL)
962 			err = got_error_from_errno("fclose");
963 	}
964 	free(path_refs);
965 	free(path);
966 	if (tmppath) {
967 		if (unlink(tmppath) != 0 && err == NULL)
968 			err = got_error_from_errno2("unlink", tmppath);
969 		free(tmppath);
970 	}
971 	return err ? err : unlock_err;
972 }
973 
974 static const struct got_error *
975 delete_packed_ref(struct got_reference *delref, struct got_repository *repo)
976 {
977 	const struct got_error *err = NULL, *unlock_err = NULL;
978 	struct got_lockfile *lf = NULL;
979 	FILE *f = NULL, *tmpf = NULL;
980 	char *packed_refs_path, *tmppath = NULL;
981 	struct got_reflist_head refs;
982 	int found_delref = 0;
983 
984 	/* The packed-refs file does not cotain symbolic references. */
985 	if (delref->flags & GOT_REF_IS_SYMBOLIC)
986 		return got_error(GOT_ERR_BAD_REF_DATA);
987 
988 	SIMPLEQ_INIT(&refs);
989 
990 	packed_refs_path = got_repo_get_path_packed_refs(repo);
991 	if (packed_refs_path == NULL)
992 		return got_error_from_errno("got_repo_get_path_packed_refs");
993 
994 	err = got_opentemp_named(&tmppath, &tmpf, packed_refs_path);
995 	if (err)
996 		goto done;
997 
998 	if (delref->lf == NULL) {
999 		err = got_lockfile_lock(&lf, packed_refs_path);
1000 		if (err)
1001 			goto done;
1002 	}
1003 
1004 	f = fopen(packed_refs_path, "r");
1005 	if (f == NULL) {
1006 		err = got_error_from_errno2("fopen", packed_refs_path);
1007 		goto done;
1008 	}
1009 	for (;;) {
1010 		char *line;
1011 		size_t len;
1012 		const char delim[3] = {'\0', '\0', '\0'};
1013 		struct got_reference *ref;
1014 		struct got_reflist_entry *new;
1015 
1016 		line = fparseln(f, &len, NULL, delim, 0);
1017 		if (line == NULL) {
1018 			if (feof(f))
1019 				break;
1020 			err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
1021 			goto done;
1022 		}
1023 		err = parse_packed_ref_line(&ref, NULL, line);
1024 		free(line);
1025 		if (err)
1026 			goto done;
1027 		if (ref == NULL)
1028 			continue;
1029 
1030 		if (strcmp(ref->ref.ref.name, delref->ref.ref.name) == 0 &&
1031 		    memcmp(ref->ref.ref.sha1, delref->ref.ref.sha1,
1032 		    sizeof(delref->ref.ref.sha1)) == 0) {
1033 			found_delref = 1;
1034 			got_ref_close(ref);
1035 			continue;
1036 		}
1037 
1038 		err = insert_ref(&new, &refs, ref, repo);
1039 		if (err || new == NULL /* duplicate */)
1040 			got_ref_close(ref);
1041 		if (err)
1042 			goto done;
1043 	}
1044 
1045 	if (found_delref) {
1046 		struct got_reflist_entry *re;
1047 		size_t n;
1048 		struct stat sb;
1049 
1050 		n = fprintf(tmpf, "%s\n", GOT_PACKED_REFS_HEADER);
1051 		if (n != sizeof(GOT_PACKED_REFS_HEADER)) {
1052 			err = got_ferror(f, GOT_ERR_IO);
1053 			goto done;
1054 		}
1055 
1056 		SIMPLEQ_FOREACH(re, &refs, entry) {
1057 			uint8_t hex[SHA1_DIGEST_STRING_LENGTH];
1058 
1059 			if (got_sha1_digest_to_str(re->ref->ref.ref.sha1, hex,
1060 			    sizeof(hex)) == NULL) {
1061 				err = got_error(GOT_ERR_BAD_REF_DATA);
1062 				goto done;
1063 			}
1064 			n = fprintf(tmpf, "%s ", hex);
1065 			if (n != sizeof(hex)) {
1066 				err = got_ferror(f, GOT_ERR_IO);
1067 				goto done;
1068 			}
1069 			n = fprintf(tmpf, "%s\n", re->ref->ref.ref.name);
1070 			if (n != strlen(re->ref->ref.ref.name) + 1) {
1071 				err = got_ferror(f, GOT_ERR_IO);
1072 				goto done;
1073 			}
1074 		}
1075 
1076 		if (fflush(tmpf) != 0) {
1077 			err = got_error_from_errno("fflush");
1078 			goto done;
1079 		}
1080 
1081 		if (stat(packed_refs_path, &sb) != 0) {
1082 			if (errno != ENOENT) {
1083 				err = got_error_from_errno2("stat",
1084 				    packed_refs_path);
1085 				goto done;
1086 			}
1087 			sb.st_mode = GOT_DEFAULT_FILE_MODE;
1088 		}
1089 
1090 		if (rename(tmppath, packed_refs_path) != 0) {
1091 			err = got_error_from_errno3("rename", tmppath,
1092 			    packed_refs_path);
1093 			goto done;
1094 		}
1095 
1096 		if (chmod(packed_refs_path, sb.st_mode) != 0) {
1097 			err = got_error_from_errno2("chmod",
1098 			    packed_refs_path);
1099 			goto done;
1100 		}
1101 	}
1102 done:
1103 	if (delref->lf == NULL && lf)
1104 		unlock_err = got_lockfile_unlock(lf);
1105 	if (f) {
1106 		if (fclose(f) != 0 && err == NULL)
1107 			err = got_error_from_errno("fclose");
1108 	}
1109 	if (tmpf) {
1110 		unlink(tmppath);
1111 		if (fclose(tmpf) != 0 && err == NULL)
1112 			err = got_error_from_errno("fclose");
1113 	}
1114 	free(tmppath);
1115 	free(packed_refs_path);
1116 	got_ref_list_free(&refs);
1117 	return err ? err : unlock_err;
1118 }
1119 
1120 const struct got_error *
1121 got_ref_delete(struct got_reference *ref, struct got_repository *repo)
1122 {
1123 	const struct got_error *err = NULL, *unlock_err = NULL;
1124 	const char *name = got_ref_get_name(ref);
1125 	char *path_refs = NULL, *path = NULL;
1126 	struct got_lockfile *lf = NULL;
1127 
1128 	if (ref->flags & GOT_REF_IS_PACKED)
1129 		return delete_packed_ref(ref, repo);
1130 
1131 	path_refs = get_refs_dir_path(repo, name);
1132 	if (path_refs == NULL) {
1133 		err = got_error_from_errno2("get_refs_dir_path", name);
1134 		goto done;
1135 	}
1136 
1137 	if (asprintf(&path, "%s/%s", path_refs, name) == -1) {
1138 		err = got_error_from_errno("asprintf");
1139 		goto done;
1140 	}
1141 
1142 	if (ref->lf == NULL) {
1143 		err = got_lockfile_lock(&lf, path);
1144 		if (err)
1145 			goto done;
1146 	}
1147 
1148 	/* XXX: check if old content matches our expectations? */
1149 
1150 	if (unlink(path) != 0)
1151 		err = got_error_from_errno2("unlink", path);
1152 done:
1153 	if (ref->lf == NULL && lf)
1154 		unlock_err = got_lockfile_unlock(lf);
1155 
1156 	free(path_refs);
1157 	free(path);
1158 	return err ? err : unlock_err;
1159 }
1160 
1161 const struct got_error *
1162 got_ref_unlock(struct got_reference *ref)
1163 {
1164 	const struct got_error *err;
1165 	err = got_lockfile_unlock(ref->lf);
1166 	ref->lf = NULL;
1167 	return err;
1168 }