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Date:: Wed Oct 9 06:50:28 2019 UTC
Message:: show bad reference names in error messages to make such errors more clear
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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;
169 	size_t len;
170 	const char delim[3] = {'\0', '\0', '\0'};
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 	line = fparseln(f, &len, NULL, delim, 0);
187 	if (line == NULL) {
188 		err = got_error(GOT_ERR_BAD_REF_DATA);
189 		if (lock)
190 			got_lockfile_unlock(lf);
191 		goto done;
192 	}
193 
194 	err = parse_ref_line(ref, name, line);
195 	if (lock) {
196 		if (err)
197 			got_lockfile_unlock(lf);
198 		else {
199 			if (*ref)
200 				(*ref)->lf = lf;
201 			else
202 				got_lockfile_unlock(lf);
203 		}
204 	}
205 done:
206 	free(line);
207 	if (fclose(f) != 0 && err == NULL) {
208 		err = got_error_from_errno("fclose");
209 		if (*ref) {
210 			if (lock)
211 				got_ref_unlock(*ref);
212 			got_ref_close(*ref);
213 			*ref = NULL;
214 		}
215 	}
216 	return err;
217 }
218 
219 static int
220 is_well_known_ref(const char *refname)
221 {
222 	return (strcmp(refname, GOT_REF_HEAD) == 0 ||
223 	    strcmp(refname, GOT_REF_ORIG_HEAD) == 0 ||
224 	    strcmp(refname, GOT_REF_MERGE_HEAD) == 0 ||
225 	    strcmp(refname, GOT_REF_FETCH_HEAD) == 0);
226 }
227 
228 static char *
229 get_refs_dir_path(struct got_repository *repo, const char *refname)
230 {
231 	if (is_well_known_ref(refname) || strncmp(refname, "refs/", 5) == 0)
232 		return strdup(got_repo_get_path_git_dir(repo));
233 
234 	return got_repo_get_path_refs(repo);
235 }
236 
237 static int
238 is_valid_ref_name(const char *name)
239 {
240 	const char *s, *slash, *seg;
241 	const char forbidden[] = { ' ', '~', '^', ':', '?', '*', '[' , '\\' };
242 	const char *forbidden_seq[] = { "//", "..", "@{" };
243 	const char *lfs = GOT_LOCKFILE_SUFFIX;
244 	const size_t lfs_len = sizeof(GOT_LOCKFILE_SUFFIX) - 1;
245 	int i;
246 
247 	if (name[0] == '@' && name[1] == '\0')
248 		return 0;
249 
250 	slash = strchr(name, '/');
251 	if (slash == NULL)
252 		return 0;
253 
254 	s = name;
255 	seg = s;
256 	if (seg[0] == '\0' || seg[0] == '.' || seg[0] == '/')
257 		return 0;
258 	while (*s) {
259 		for (i = 0; i < nitems(forbidden); i++) {
260 			if (*s == forbidden[i])
261 				return 0;
262 		}
263 		for (i = 0; i < nitems(forbidden_seq); i++) {
264 			if (s[0] == forbidden_seq[i][0] &&
265 			    s[1] == forbidden_seq[i][1])
266 				return 0;
267 		}
268 		if (iscntrl((unsigned char)s[0]))
269 			return 0;
270 		if (s[0] == '.' && s[1] == '\0')
271 			return 0;
272 		if (*s == '/') {
273 			const char *nextseg = s + 1;
274 			if (nextseg[0] == '\0' || nextseg[0] == '.' ||
275 			    nextseg[0] == '/')
276 				return 0;
277 			if (seg <= s - lfs_len &&
278 			    strncmp(s - lfs_len, lfs, lfs_len) == 0)
279 				return 0;
280 			seg = nextseg;
281 		}
282 		s++;
283 	}
284 
285 	if (seg <= s - lfs_len &&
286 	    strncmp(s - lfs_len, lfs, lfs_len) == 0)
287 		return 0;
288 
289 	return 1;
290 }
291 
292 const struct got_error *
293 got_ref_alloc(struct got_reference **ref, const char *name,
294     struct got_object_id *id)
295 {
296 	if (!is_valid_ref_name(name))
297 		return got_error_path(name, GOT_ERR_BAD_REF_NAME);
298 
299 	return alloc_ref(ref, name, id, 0);
300 }
301 
302 const struct got_error *
303 got_ref_alloc_symref(struct got_reference **ref, const char *name,
304 	struct got_reference *target_ref)
305 {
306 	if (!is_valid_ref_name(name))
307 		return got_error_path(name, GOT_ERR_BAD_REF_NAME);
308 
309 	return alloc_symref(ref, name, got_ref_get_name(target_ref), 0);
310 }
311 
312 static const struct got_error *
313 parse_packed_ref_line(struct got_reference **ref, const char *abs_refname,
314     const char *line)
315 {
316 	struct got_object_id id;
317 	const char *name;
318 
319 	*ref = NULL;
320 
321 	if (line[0] == '#' || line[0] == '^')
322 		return NULL;
323 
324 	if (!got_parse_sha1_digest(id.sha1, line))
325 		return got_error(GOT_ERR_BAD_REF_DATA);
326 
327 	if (abs_refname) {
328 		if (strcmp(line + SHA1_DIGEST_STRING_LENGTH, abs_refname) != 0)
329 			return NULL;
330 		name = abs_refname;
331 	} else
332 		name = line + SHA1_DIGEST_STRING_LENGTH;
333 
334 	return alloc_ref(ref, name, &id, GOT_REF_IS_PACKED);
335 }
336 
337 static const struct got_error *
338 open_packed_ref(struct got_reference **ref, FILE *f, const char **subdirs,
339     int nsubdirs, const char *refname)
340 {
341 	const struct got_error *err = NULL;
342 	char *abs_refname;
343 	char *line;
344 	size_t len;
345 	const char delim[3] = {'\0', '\0', '\0'};
346 	int i, ref_is_absolute = (strncmp(refname, "refs/", 5) == 0);
347 
348 	*ref = NULL;
349 
350 	if (ref_is_absolute)
351 		abs_refname = (char *)refname;
352 	do {
353 		line = fparseln(f, &len, NULL, delim, 0);
354 		if (line == NULL) {
355 			if (feof(f))
356 				break;
357 			err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
358 			break;
359 		}
360 		for (i = 0; i < nsubdirs; i++) {
361 			if (!ref_is_absolute &&
362 			    asprintf(&abs_refname, "refs/%s/%s", subdirs[i],
363 			    refname) == -1)
364 				return got_error_from_errno("asprintf");
365 			err = parse_packed_ref_line(ref, abs_refname, line);
366 			if (!ref_is_absolute)
367 				free(abs_refname);
368 			if (err || *ref != NULL)
369 				break;
370 		}
371 		free(line);
372 		if (err)
373 			break;
374 	} while (*ref == NULL);
375 
376 	return err;
377 }
378 
379 static const struct got_error *
380 open_ref(struct got_reference **ref, const char *path_refs, const char *subdir,
381     const char *name, int lock)
382 {
383 	const struct got_error *err = NULL;
384 	char *path = NULL;
385 	char *absname = NULL;
386 	int ref_is_absolute = (strncmp(name, "refs/", 5) == 0);
387 	int ref_is_well_known = is_well_known_ref(name);
388 
389 	*ref = NULL;
390 
391 	if (ref_is_absolute || ref_is_well_known) {
392 		if (asprintf(&path, "%s/%s", path_refs, name) == -1)
393 			return got_error_from_errno("asprintf");
394 		absname = (char *)name;
395 	} else {
396 		if (asprintf(&path, "%s/%s%s%s", path_refs, subdir,
397 		    subdir[0] ? "/" : "", name) == -1)
398 			return got_error_from_errno("asprintf");
399 
400 		if (asprintf(&absname, "refs/%s%s%s",
401 		    subdir, subdir[0] ? "/" : "", name) == -1) {
402 			err = got_error_from_errno("asprintf");
403 			goto done;
404 		}
405 	}
406 
407 	err = parse_ref_file(ref, absname, path, lock);
408 done:
409 	if (!ref_is_absolute && !ref_is_well_known)
410 		free(absname);
411 	free(path);
412 	return err;
413 }
414 
415 const struct got_error *
416 got_ref_open(struct got_reference **ref, struct got_repository *repo,
417    const char *refname, int lock)
418 {
419 	const struct got_error *err = NULL;
420 	char *path_refs = NULL;
421 	const char *subdirs[] = {
422 	    GOT_REF_HEADS, GOT_REF_TAGS, GOT_REF_REMOTES
423 	};
424 	int i, well_known = is_well_known_ref(refname);
425 	struct got_lockfile *lf = NULL;
426 
427 	*ref = NULL;
428 
429 	path_refs = get_refs_dir_path(repo, refname);
430 	if (path_refs == NULL) {
431 		err = got_error_from_errno2("get_refs_dir_path", refname);
432 		goto done;
433 	}
434 
435 	if (well_known) {
436 		err = open_ref(ref, path_refs, "", refname, lock);
437 	} else {
438 		char *packed_refs_path;
439 		FILE *f;
440 
441 		/* Search on-disk refs before packed refs! */
442 		for (i = 0; i < nitems(subdirs); i++) {
443 			err = open_ref(ref, path_refs, subdirs[i], refname,
444 			    lock);
445 			if (err || *ref)
446 				goto done;
447 		}
448 
449 		packed_refs_path = got_repo_get_path_packed_refs(repo);
450 		if (packed_refs_path == NULL) {
451 			err = got_error_from_errno(
452 			    "got_repo_get_path_packed_refs");
453 			goto done;
454 		}
455 
456 		if (lock) {
457 			err = got_lockfile_lock(&lf, packed_refs_path);
458 			if (err)
459 				goto done;
460 		}
461 		f = fopen(packed_refs_path, "rb");
462 		free(packed_refs_path);
463 		if (f != NULL) {
464 			err = open_packed_ref(ref, f, subdirs, nitems(subdirs),
465 			    refname);
466 			if (!err) {
467 				if (fclose(f) != 0) {
468 					err = got_error_from_errno("fclose");
469 					got_ref_close(*ref);
470 					*ref = NULL;
471 				} else if (*ref)
472 					(*ref)->lf = lf;
473 			}
474 		}
475 	}
476 done:
477 	if (!err && *ref == NULL)
478 		err = got_error_not_ref(refname);
479 	if (err && lf)
480 		got_lockfile_unlock(lf);
481 	free(path_refs);
482 	return err;
483 }
484 
485 void
486 got_ref_close(struct got_reference *ref)
487 {
488 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
489 		free(ref->ref.symref.name);
490 		free(ref->ref.symref.ref);
491 	} else
492 		free(ref->ref.ref.name);
493 	free(ref);
494 }
495 
496 struct got_reference *
497 got_ref_dup(struct got_reference *ref)
498 {
499 	struct got_reference *ret;
500 
501 	ret = calloc(1, sizeof(*ret));
502 	if (ret == NULL)
503 		return NULL;
504 
505 	ret->flags = ref->flags;
506 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
507 		ret->ref.symref.name = strdup(ref->ref.symref.name);
508 		if (ret->ref.symref.name == NULL) {
509 			free(ret);
510 			return NULL;
511 		}
512 		ret->ref.symref.ref = strdup(ref->ref.symref.ref);
513 		if (ret->ref.symref.ref == NULL) {
514 			free(ret->ref.symref.name);
515 			free(ret);
516 			return NULL;
517 		}
518 	} else {
519 		ref->ref.ref.name = strdup(ref->ref.ref.name);
520 		if (ref->ref.ref.name == NULL) {
521 			free(ret);
522 			return NULL;
523 		}
524 		memcpy(ret->ref.ref.sha1, ref->ref.ref.sha1,
525 		    sizeof(ret->ref.ref.sha1));
526 	}
527 
528 	return ret;
529 }
530 
531 const struct got_error *
532 got_reflist_entry_dup(struct got_reflist_entry **newp,
533     struct got_reflist_entry *re)
534 {
535 	const struct got_error *err = NULL;
536 	struct got_reflist_entry *new;
537 
538 	*newp = NULL;
539 
540 	new = malloc(sizeof(*new));
541 	if (new == NULL)
542 		return got_error_from_errno("malloc");
543 
544 	new->ref = got_ref_dup(re->ref);
545 	if (new->ref == NULL) {
546 		err = got_error_from_errno("got_ref_dup");
547 		free(new);
548 		return err;
549 	}
550 
551 	new->id = got_object_id_dup(re->id);
552 	if (new->id == NULL) {
553 		err = got_error_from_errno("got_ref_dup");
554 		free(new->id);
555 		free(new);
556 		return err;
557 	}
558 
559 	*newp = new;
560 	return NULL;
561 }
562 
563 static const struct got_error *
564 resolve_symbolic_ref(struct got_reference **resolved,
565     struct got_repository *repo, struct got_reference *ref)
566 {
567 	struct got_reference *nextref;
568 	const struct got_error *err;
569 
570 	err = got_ref_open(&nextref, repo, ref->ref.symref.ref, 0);
571 	if (err)
572 		return err;
573 
574 	if (nextref->flags & GOT_REF_IS_SYMBOLIC)
575 		err = resolve_symbolic_ref(resolved, repo, nextref);
576 	else
577 		*resolved = got_ref_dup(nextref);
578 
579 	got_ref_close(nextref);
580 	return err;
581 }
582 
583 static const struct got_error *
584 ref_resolve(struct got_object_id **id, struct got_repository *repo,
585     struct got_reference *ref, int recursion)
586 {
587 	const struct got_error *err;
588 
589 	if (recursion <= 0)
590 		return got_error_msg(GOT_ERR_RECURSION,
591 		    "reference recursion limit reached");
592 
593 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
594 		struct got_reference *resolved = NULL;
595 		err = resolve_symbolic_ref(&resolved, repo, ref);
596 		if (err == NULL)
597 			err = ref_resolve(id, repo, resolved, --recursion);
598 		if (resolved)
599 			got_ref_close(resolved);
600 		return err;
601 	}
602 
603 	*id = calloc(1, sizeof(**id));
604 	if (*id == NULL)
605 		return got_error_from_errno("calloc");
606 	memcpy((*id)->sha1, ref->ref.ref.sha1, sizeof((*id)->sha1));
607 	return NULL;
608 }
609 
610 const struct got_error *
611 got_ref_resolve(struct got_object_id **id, struct got_repository *repo,
612     struct got_reference *ref)
613 {
614 	return ref_resolve(id, repo, ref, GOT_REF_RECURSE_MAX);
615 }
616 
617 char *
618 got_ref_to_str(struct got_reference *ref)
619 {
620 	char *str;
621 
622 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
623 		return strdup(ref->ref.symref.ref);
624 
625 	str = malloc(SHA1_DIGEST_STRING_LENGTH);
626 	if (str == NULL)
627 		return NULL;
628 
629 	if (got_sha1_digest_to_str(ref->ref.ref.sha1, str,
630 	    SHA1_DIGEST_STRING_LENGTH) == NULL) {
631 		free(str);
632 		return NULL;
633 	}
634 
635 	return str;
636 }
637 
638 const char *
639 got_ref_get_name(struct got_reference *ref)
640 {
641 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
642 		return ref->ref.symref.name;
643 
644 	return ref->ref.ref.name;
645 }
646 
647 const char *
648 got_ref_get_symref_target(struct got_reference *ref)
649 {
650 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
651 		return ref->ref.symref.ref;
652 
653 	return NULL;
654 }
655 
656 const struct got_error *
657 got_ref_cmp_by_name(void *arg, int *cmp, struct got_reference *re1,
658     struct got_reference* re2)
659 {
660 	const char *name1 = got_ref_get_name(re1);
661 	const char *name2 = got_ref_get_name(re2);
662 
663 	*cmp = got_path_cmp(name1, name2, strlen(name1), strlen(name2));
664 	return NULL;
665 }
666 
667 static const struct got_error *
668 insert_ref(struct got_reflist_entry **newp, struct got_reflist_head *refs,
669     struct got_reference *ref, struct got_repository *repo,
670     got_ref_cmp_cb cmp_cb, void *cmp_arg)
671 {
672 	const struct got_error *err;
673 	struct got_object_id *id;
674 	struct got_reflist_entry *new, *re, *prev = NULL;
675 	int cmp;
676 
677 	*newp = NULL;
678 
679 	err = got_ref_resolve(&id, repo, ref);
680 	if (err)
681 		return err;
682 
683 	new = malloc(sizeof(*new));
684 	if (new == NULL) {
685 		free(id);
686 		return got_error_from_errno("malloc");
687 	}
688 	new->ref = ref;
689 	new->id = id;
690 	*newp = new;
691 
692 	/*
693 	 * We must de-duplicate entries on insert because packed-refs may
694 	 * contain redundant entries. On-disk refs take precedence.
695 	 * This code assumes that on-disk revs are read before packed-refs.
696 	 * We're iterating the list anyway, so insert elements sorted by name.
697 	 */
698 	re = SIMPLEQ_FIRST(refs);
699 	while (re) {
700 		err = (*cmp_cb)(cmp_arg, &cmp, re->ref, new->ref);
701 		if (err)
702 			return err;
703 		if (cmp == 0) {
704 			/* duplicate */
705 			free(new->id);
706 			free(new);
707 			*newp = NULL;
708 			return NULL;
709 		} else if (cmp > 0) {
710 			if (prev)
711 				SIMPLEQ_INSERT_AFTER(refs, prev, new, entry);
712 			else
713 				SIMPLEQ_INSERT_HEAD(refs, new, entry);
714 			return NULL;
715 		} else {
716 			prev = re;
717 			re = SIMPLEQ_NEXT(re, entry);
718 		}
719 	}
720 
721 	SIMPLEQ_INSERT_TAIL(refs, new, entry);
722 	return NULL;
723 }
724 
725 static const struct got_error *
726 gather_on_disk_refs(struct got_reflist_head *refs, const char *path_refs,
727     const char *subdir, struct got_repository *repo,
728     got_ref_cmp_cb cmp_cb, void *cmp_arg)
729 {
730 	const struct got_error *err = NULL;
731 	DIR *d = NULL;
732 	char *path_subdir;
733 
734 	if (asprintf(&path_subdir, "%s/%s", path_refs, subdir) == -1)
735 		return got_error_from_errno("asprintf");
736 
737 	d = opendir(path_subdir);
738 	if (d == NULL)
739 		goto done;
740 
741 	for (;;) {
742 		struct dirent *dent;
743 		struct got_reference *ref;
744 		char *child;
745 
746 		dent = readdir(d);
747 		if (dent == NULL)
748 			break;
749 
750 		if (strcmp(dent->d_name, ".") == 0 ||
751 		    strcmp(dent->d_name, "..") == 0)
752 			continue;
753 
754 		switch (dent->d_type) {
755 		case DT_REG:
756 			err = open_ref(&ref, path_refs, subdir, dent->d_name,
757 			    0);
758 			if (err)
759 				goto done;
760 			if (ref) {
761 				struct got_reflist_entry *new;
762 				err = insert_ref(&new, refs, ref, repo,
763 				    cmp_cb, cmp_arg);
764 				if (err || new == NULL /* duplicate */)
765 					got_ref_close(ref);
766 				if (err)
767 					goto done;
768 			}
769 			break;
770 		case DT_DIR:
771 			if (asprintf(&child, "%s%s%s", subdir,
772 			    subdir[0] == '\0' ? "" : "/", dent->d_name) == -1) {
773 				err = got_error_from_errno("asprintf");
774 				break;
775 			}
776 			err = gather_on_disk_refs(refs, path_refs, child, repo,
777 			    cmp_cb, cmp_arg);
778 			free(child);
779 			break;
780 		default:
781 			break;
782 		}
783 	}
784 done:
785 	if (d)
786 		closedir(d);
787 	free(path_subdir);
788 	return err;
789 }
790 
791 const struct got_error *
792 got_ref_list(struct got_reflist_head *refs, struct got_repository *repo,
793     const char *ref_namespace, got_ref_cmp_cb cmp_cb, void *cmp_arg)
794 {
795 	const struct got_error *err;
796 	char *packed_refs_path, *path_refs = NULL;
797 	const char *ondisk_ref_namespace = NULL;
798 	FILE *f = NULL;
799 	struct got_reference *ref;
800 	struct got_reflist_entry *new;
801 
802 	if (ref_namespace == NULL || ref_namespace[0] == '\0') {
803 		/* HEAD ref should always exist. */
804 		path_refs = get_refs_dir_path(repo, GOT_REF_HEAD);
805 		if (path_refs == NULL) {
806 			err = got_error_from_errno("get_refs_dir_path");
807 			goto done;
808 		}
809 		err = open_ref(&ref, path_refs, "", GOT_REF_HEAD, 0);
810 		if (err)
811 			goto done;
812 		err = insert_ref(&new, refs, ref, repo, cmp_cb, cmp_arg);
813 		if (err || new == NULL /* duplicate */)
814 			got_ref_close(ref);
815 		if (err)
816 			goto done;
817 	}
818 
819 	ondisk_ref_namespace = ref_namespace;
820 	if (ref_namespace && strncmp(ref_namespace, "refs/", 5) == 0)
821 		ondisk_ref_namespace += 5;
822 
823 	/* Gather on-disk refs before parsing packed-refs. */
824 	free(path_refs);
825 	path_refs = get_refs_dir_path(repo, "");
826 	if (path_refs == NULL) {
827 		err = got_error_from_errno("get_refs_dir_path");
828 		goto done;
829 	}
830 	err = gather_on_disk_refs(refs, path_refs,
831 	    ondisk_ref_namespace ? ondisk_ref_namespace : "", repo,
832 	    cmp_cb, cmp_arg);
833 	if (err)
834 		goto done;
835 
836 	/*
837 	 * The packed-refs file may contain redundant entries, in which
838 	 * case on-disk refs take precedence.
839 	 */
840 	packed_refs_path = got_repo_get_path_packed_refs(repo);
841 	if (packed_refs_path == NULL) {
842 		err = got_error_from_errno("got_repo_get_path_packed_refs");
843 		goto done;
844 	}
845 
846 	f = fopen(packed_refs_path, "r");
847 	free(packed_refs_path);
848 	if (f) {
849 		char *line;
850 		size_t len;
851 		const char delim[3] = {'\0', '\0', '\0'};
852 		for (;;) {
853 			line = fparseln(f, &len, NULL, delim, 0);
854 			if (line == NULL) {
855 				if (feof(f))
856 					break;
857 				err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
858 				goto done;
859 			}
860 			err = parse_packed_ref_line(&ref, NULL, line);
861 			free(line);
862 			if (err)
863 				goto done;
864 			if (ref) {
865 				if (ref_namespace) {
866 					const char *name;
867 					name = got_ref_get_name(ref);
868 					if (strncmp(name, ref_namespace,
869 					    strlen(ref_namespace)) != 0) {
870 						got_ref_close(ref);
871 						continue;
872 					}
873 				}
874 				err = insert_ref(&new, refs, ref, repo,
875 				    cmp_cb, cmp_arg);
876 				if (err || new == NULL /* duplicate */)
877 					got_ref_close(ref);
878 				if (err)
879 					goto done;
880 			}
881 		}
882 	}
883 done:
884 	free(path_refs);
885 	if (f && fclose(f) != 0 && err == NULL)
886 		err = got_error_from_errno("fclose");
887 	return err;
888 }
889 
890 void
891 got_ref_list_free(struct got_reflist_head *refs)
892 {
893 	struct got_reflist_entry *re;
894 
895 	while (!SIMPLEQ_EMPTY(refs)) {
896 		re = SIMPLEQ_FIRST(refs);
897 		SIMPLEQ_REMOVE_HEAD(refs, entry);
898 		got_ref_close(re->ref);
899 		free(re->id);
900 		free(re);
901 	}
902 
903 }
904 
905 int
906 got_ref_is_symbolic(struct got_reference *ref)
907 {
908 	return (ref->flags & GOT_REF_IS_SYMBOLIC);
909 }
910 
911 const struct got_error *
912 got_ref_change_ref(struct got_reference *ref, struct got_object_id *id)
913 {
914 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
915 		return got_error(GOT_ERR_BAD_REF_TYPE);
916 
917 	memcpy(ref->ref.ref.sha1, id->sha1, sizeof(ref->ref.ref.sha1));
918 	return NULL;
919 }
920 
921 const struct got_error *
922 got_ref_change_symref(struct got_reference *ref, char *refname)
923 {
924 	char *new_name;
925 
926 	if ((ref->flags & GOT_REF_IS_SYMBOLIC) == 0)
927 		return got_error(GOT_ERR_BAD_REF_TYPE);
928 
929 	new_name = strdup(refname);
930 	if (new_name == NULL)
931 		return got_error_from_errno("strdup");
932 
933 	free(ref->ref.symref.name);
934 	ref->ref.symref.name = new_name;
935 	return NULL;
936 }
937 
938 const struct got_error *
939 got_ref_write(struct got_reference *ref, struct got_repository *repo)
940 {
941 	const struct got_error *err = NULL, *unlock_err = NULL;
942 	const char *name = got_ref_get_name(ref);
943 	char *path_refs = NULL, *path = NULL, *tmppath = NULL;
944 	struct got_lockfile *lf = NULL;
945 	FILE *f = NULL;
946 	size_t n;
947 	struct stat sb;
948 
949 	path_refs = get_refs_dir_path(repo, name);
950 	if (path_refs == NULL) {
951 		err = got_error_from_errno2("get_refs_dir_path", name);
952 		goto done;
953 	}
954 
955 	if (asprintf(&path, "%s/%s", path_refs, name) == -1) {
956 		err = got_error_from_errno("asprintf");
957 		goto done;
958 	}
959 
960 	err = got_opentemp_named(&tmppath, &f, path);
961 	if (err) {
962 		char *parent;
963 		if (!(err->code == GOT_ERR_ERRNO && errno == ENOENT))
964 			goto done;
965 		err = got_path_dirname(&parent, path);
966 		if (err)
967 			goto done;
968 		err = got_path_mkdir(parent);
969 		free(parent);
970 		if (err)
971 			goto done;
972 		err = got_opentemp_named(&tmppath, &f, path);
973 		if (err)
974 			goto done;
975 	}
976 
977 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
978 		n = fprintf(f, "ref: %s\n", ref->ref.symref.ref);
979 		if (n != strlen(ref->ref.symref.ref) + 6) {
980 			err = got_ferror(f, GOT_ERR_IO);
981 			goto done;
982 		}
983 	} else {
984 		char hex[SHA1_DIGEST_STRING_LENGTH];
985 		if (got_sha1_digest_to_str(ref->ref.ref.sha1, hex,
986 		    sizeof(hex)) == NULL) {
987 			err = got_error(GOT_ERR_BAD_REF_DATA);
988 			goto done;
989 		}
990 		n = fprintf(f, "%s\n", hex);
991 		if (n != sizeof(hex)) {
992 			err = got_ferror(f, GOT_ERR_IO);
993 			goto done;
994 		}
995 	}
996 
997 	if (ref->lf == NULL) {
998 		err = got_lockfile_lock(&lf, path);
999 		if (err)
1000 			goto done;
1001 	}
1002 
1003 	/* XXX: check if old content matches our expectations? */
1004 
1005 	if (stat(path, &sb) != 0) {
1006 		if (errno != ENOENT) {
1007 			err = got_error_from_errno2("stat", path);
1008 			goto done;
1009 		}
1010 		sb.st_mode = GOT_DEFAULT_FILE_MODE;
1011 	}
1012 
1013 	if (rename(tmppath, path) != 0) {
1014 		err = got_error_from_errno3("rename", tmppath, path);
1015 		goto done;
1016 	}
1017 	free(tmppath);
1018 	tmppath = NULL;
1019 
1020 	if (chmod(path, sb.st_mode) != 0) {
1021 		err = got_error_from_errno2("chmod", path);
1022 		goto done;
1023 	}
1024 done:
1025 	if (ref->lf == NULL && lf)
1026 		unlock_err = got_lockfile_unlock(lf);
1027 	if (f) {
1028 		if (fclose(f) != 0 && err == NULL)
1029 			err = got_error_from_errno("fclose");
1030 	}
1031 	free(path_refs);
1032 	free(path);
1033 	if (tmppath) {
1034 		if (unlink(tmppath) != 0 && err == NULL)
1035 			err = got_error_from_errno2("unlink", tmppath);
1036 		free(tmppath);
1037 	}
1038 	return err ? err : unlock_err;
1039 }
1040 
1041 static const struct got_error *
1042 delete_packed_ref(struct got_reference *delref, struct got_repository *repo)
1043 {
1044 	const struct got_error *err = NULL, *unlock_err = NULL;
1045 	struct got_lockfile *lf = NULL;
1046 	FILE *f = NULL, *tmpf = NULL;
1047 	char *packed_refs_path, *tmppath = NULL;
1048 	struct got_reflist_head refs;
1049 	int found_delref = 0;
1050 
1051 	/* The packed-refs file does not cotain symbolic references. */
1052 	if (delref->flags & GOT_REF_IS_SYMBOLIC)
1053 		return got_error(GOT_ERR_BAD_REF_DATA);
1054 
1055 	SIMPLEQ_INIT(&refs);
1056 
1057 	packed_refs_path = got_repo_get_path_packed_refs(repo);
1058 	if (packed_refs_path == NULL)
1059 		return got_error_from_errno("got_repo_get_path_packed_refs");
1060 
1061 	err = got_opentemp_named(&tmppath, &tmpf, packed_refs_path);
1062 	if (err)
1063 		goto done;
1064 
1065 	if (delref->lf == NULL) {
1066 		err = got_lockfile_lock(&lf, packed_refs_path);
1067 		if (err)
1068 			goto done;
1069 	}
1070 
1071 	f = fopen(packed_refs_path, "r");
1072 	if (f == NULL) {
1073 		err = got_error_from_errno2("fopen", packed_refs_path);
1074 		goto done;
1075 	}
1076 	for (;;) {
1077 		char *line;
1078 		size_t len;
1079 		const char delim[3] = {'\0', '\0', '\0'};
1080 		struct got_reference *ref;
1081 		struct got_reflist_entry *new;
1082 
1083 		line = fparseln(f, &len, NULL, delim, 0);
1084 		if (line == NULL) {
1085 			if (feof(f))
1086 				break;
1087 			err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
1088 			goto done;
1089 		}
1090 		err = parse_packed_ref_line(&ref, NULL, line);
1091 		free(line);
1092 		if (err)
1093 			goto done;
1094 		if (ref == NULL)
1095 			continue;
1096 
1097 		if (strcmp(ref->ref.ref.name, delref->ref.ref.name) == 0 &&
1098 		    memcmp(ref->ref.ref.sha1, delref->ref.ref.sha1,
1099 		    sizeof(delref->ref.ref.sha1)) == 0) {
1100 			found_delref = 1;
1101 			got_ref_close(ref);
1102 			continue;
1103 		}
1104 
1105 		err = insert_ref(&new, &refs, ref, repo,
1106 		    got_ref_cmp_by_name, NULL);
1107 		if (err || new == NULL /* duplicate */)
1108 			got_ref_close(ref);
1109 		if (err)
1110 			goto done;
1111 	}
1112 
1113 	if (found_delref) {
1114 		struct got_reflist_entry *re;
1115 		size_t n;
1116 		struct stat sb;
1117 
1118 		n = fprintf(tmpf, "%s\n", GOT_PACKED_REFS_HEADER);
1119 		if (n != sizeof(GOT_PACKED_REFS_HEADER)) {
1120 			err = got_ferror(f, GOT_ERR_IO);
1121 			goto done;
1122 		}
1123 
1124 		SIMPLEQ_FOREACH(re, &refs, entry) {
1125 			uint8_t hex[SHA1_DIGEST_STRING_LENGTH];
1126 
1127 			if (got_sha1_digest_to_str(re->ref->ref.ref.sha1, hex,
1128 			    sizeof(hex)) == NULL) {
1129 				err = got_error(GOT_ERR_BAD_REF_DATA);
1130 				goto done;
1131 			}
1132 			n = fprintf(tmpf, "%s ", hex);
1133 			if (n != sizeof(hex)) {
1134 				err = got_ferror(f, GOT_ERR_IO);
1135 				goto done;
1136 			}
1137 			n = fprintf(tmpf, "%s\n", re->ref->ref.ref.name);
1138 			if (n != strlen(re->ref->ref.ref.name) + 1) {
1139 				err = got_ferror(f, GOT_ERR_IO);
1140 				goto done;
1141 			}
1142 		}
1143 
1144 		if (fflush(tmpf) != 0) {
1145 			err = got_error_from_errno("fflush");
1146 			goto done;
1147 		}
1148 
1149 		if (stat(packed_refs_path, &sb) != 0) {
1150 			if (errno != ENOENT) {
1151 				err = got_error_from_errno2("stat",
1152 				    packed_refs_path);
1153 				goto done;
1154 			}
1155 			sb.st_mode = GOT_DEFAULT_FILE_MODE;
1156 		}
1157 
1158 		if (rename(tmppath, packed_refs_path) != 0) {
1159 			err = got_error_from_errno3("rename", tmppath,
1160 			    packed_refs_path);
1161 			goto done;
1162 		}
1163 
1164 		if (chmod(packed_refs_path, sb.st_mode) != 0) {
1165 			err = got_error_from_errno2("chmod",
1166 			    packed_refs_path);
1167 			goto done;
1168 		}
1169 	}
1170 done:
1171 	if (delref->lf == NULL && lf)
1172 		unlock_err = got_lockfile_unlock(lf);
1173 	if (f) {
1174 		if (fclose(f) != 0 && err == NULL)
1175 			err = got_error_from_errno("fclose");
1176 	}
1177 	if (tmpf) {
1178 		unlink(tmppath);
1179 		if (fclose(tmpf) != 0 && err == NULL)
1180 			err = got_error_from_errno("fclose");
1181 	}
1182 	free(tmppath);
1183 	free(packed_refs_path);
1184 	got_ref_list_free(&refs);
1185 	return err ? err : unlock_err;
1186 }
1187 
1188 const struct got_error *
1189 got_ref_delete(struct got_reference *ref, struct got_repository *repo)
1190 {
1191 	const struct got_error *err = NULL, *unlock_err = NULL;
1192 	const char *name = got_ref_get_name(ref);
1193 	char *path_refs = NULL, *path = NULL;
1194 	struct got_lockfile *lf = NULL;
1195 
1196 	if (ref->flags & GOT_REF_IS_PACKED)
1197 		return delete_packed_ref(ref, repo);
1198 
1199 	path_refs = get_refs_dir_path(repo, name);
1200 	if (path_refs == NULL) {
1201 		err = got_error_from_errno2("get_refs_dir_path", name);
1202 		goto done;
1203 	}
1204 
1205 	if (asprintf(&path, "%s/%s", path_refs, name) == -1) {
1206 		err = got_error_from_errno("asprintf");
1207 		goto done;
1208 	}
1209 
1210 	if (ref->lf == NULL) {
1211 		err = got_lockfile_lock(&lf, path);
1212 		if (err)
1213 			goto done;
1214 	}
1215 
1216 	/* XXX: check if old content matches our expectations? */
1217 
1218 	if (unlink(path) != 0)
1219 		err = got_error_from_errno2("unlink", path);
1220 done:
1221 	if (ref->lf == NULL && lf)
1222 		unlock_err = got_lockfile_unlock(lf);
1223 
1224 	free(path_refs);
1225 	free(path);
1226 	return err ? err : unlock_err;
1227 }
1228 
1229 const struct got_error *
1230 got_ref_unlock(struct got_reference *ref)
1231 {
1232 	const struct got_error *err;
1233 	err = got_lockfile_unlock(ref->lf);
1234 	ref->lf = NULL;
1235 	return err;
1236 }