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Date:: Mon May 13 21:09:11 2019 UTC
Message:: make open_ref() tolerate missing reference dirs and files
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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 /* A non-symbolic reference (there is no better designation). */
68 struct got_ref {
69 	char *name;
70 	u_int8_t sha1[SHA1_DIGEST_LENGTH];
71 };
72 
73 /* A reference which points to an arbitrary object. */
74 struct got_reference {
75 	unsigned int flags;
76 #define GOT_REF_IS_SYMBOLIC	0x01
77 #define GOT_REF_IS_PACKED	0x02
78 
79 	union {
80 		struct got_ref ref;
81 		struct got_symref symref;
82 	} ref;
83 
84 	struct got_lockfile *lf;
85 };
86 
87 static const struct got_error *
88 alloc_ref(struct got_reference **ref, const char *name,
89     struct got_object_id *id, int flags)
90 {
91 	const struct got_error *err = NULL;
92 
93 	*ref = calloc(1, sizeof(**ref));
94 	if (*ref == NULL)
95 		return got_error_from_errno("calloc");
96 
97 	memcpy((*ref)->ref.ref.sha1, id->sha1, sizeof((*ref)->ref.ref.sha1));
98 	(*ref)->flags = flags;
99 	(*ref)->ref.ref.name = strdup(name);
100 	if ((*ref)->ref.ref.name == NULL) {
101 		err = got_error_from_errno("strdup");
102 		got_ref_close(*ref);
103 		*ref = NULL;
104 	}
105 	return err;
106 }
107 
108 static const struct got_error *
109 alloc_symref(struct got_reference **ref, const char *name,
110     const char *target_ref, int flags)
111 {
112 	const struct got_error *err = NULL;
113 
114 	*ref = calloc(1, sizeof(**ref));
115 	if (*ref == NULL)
116 		return got_error_from_errno("calloc");
117 
118 	(*ref)->flags = GOT_REF_IS_SYMBOLIC | flags;
119 	(*ref)->ref.symref.name = strdup(name);
120 	if ((*ref)->ref.symref.name == NULL) {
121 		err = got_error_from_errno("strdup");
122 		got_ref_close(*ref);
123 		*ref = NULL;
124 	}
125 	(*ref)->ref.symref.ref = strdup(target_ref);
126 	if ((*ref)->ref.symref.ref == NULL) {
127 		err = got_error_from_errno("strdup");
128 		got_ref_close(*ref);
129 		*ref = NULL;
130 	}
131 	return err;
132 }
133 
134 static const struct got_error *
135 parse_symref(struct got_reference **ref, const char *name, const char *line)
136 {
137 	if (line[0] == '\0')
138 		return got_error(GOT_ERR_BAD_REF_DATA);
139 
140 	return alloc_symref(ref, name, line, 0);
141 }
142 
143 static const struct got_error *
144 parse_ref_line(struct got_reference **ref, const char *name, const char *line)
145 {
146 	struct got_object_id id;
147 
148 	if (strncmp(line, "ref: ", 5) == 0) {
149 		line += 5;
150 		return parse_symref(ref, name, line);
151 	}
152 
153 	if (!got_parse_sha1_digest(id.sha1, line))
154 		return got_error(GOT_ERR_BAD_REF_DATA);
155 
156 	return alloc_ref(ref, name, &id, 0);
157 }
158 
159 static const struct got_error *
160 parse_ref_file(struct got_reference **ref, const char *name,
161     const char *abspath, int lock)
162 {
163 	const struct got_error *err = NULL;
164 	FILE *f;
165 	char *line;
166 	size_t len;
167 	const char delim[3] = {'\0', '\0', '\0'};
168 	struct got_lockfile *lf = NULL;
169 
170 	if (lock) {
171 		err = got_lockfile_lock(&lf, abspath);
172 		if (err)
173 			return (err);
174 	}
175 
176 	f = fopen(abspath, "rb");
177 	if (f == NULL) {
178 		if (lock)
179 			got_lockfile_unlock(lf);
180 		return NULL;
181 	}
182 
183 	line = fparseln(f, &len, NULL, delim, 0);
184 	if (line == NULL) {
185 		err = got_error(GOT_ERR_BAD_REF_DATA);
186 		if (lock)
187 			got_lockfile_unlock(lf);
188 		goto done;
189 	}
190 
191 	err = parse_ref_line(ref, name, line);
192 	if (lock) {
193 		if (err)
194 			got_lockfile_unlock(lf);
195 		else {
196 			if (*ref)
197 				(*ref)->lf = lf;
198 			else
199 				got_lockfile_unlock(lf);
200 		}
201 	}
202 done:
203 	free(line);
204 	if (fclose(f) != 0 && err == NULL) {
205 		err = got_error_from_errno("fclose");
206 		if (*ref) {
207 			if (lock)
208 				got_ref_unlock(*ref);
209 			got_ref_close(*ref);
210 			*ref = NULL;
211 		}
212 	}
213 	return err;
214 }
215 
216 static int
217 is_well_known_ref(const char *refname)
218 {
219 	return (strcmp(refname, GOT_REF_HEAD) == 0 ||
220 	    strcmp(refname, GOT_REF_ORIG_HEAD) == 0 ||
221 	    strcmp(refname, GOT_REF_MERGE_HEAD) == 0 ||
222 	    strcmp(refname, GOT_REF_FETCH_HEAD) == 0);
223 }
224 
225 static char *
226 get_refs_dir_path(struct got_repository *repo, const char *refname)
227 {
228 	if (is_well_known_ref(refname) || strncmp(refname, "refs/", 5) == 0)
229 		return strdup(got_repo_get_path_git_dir(repo));
230 
231 	return got_repo_get_path_refs(repo);
232 }
233 
234 static int
235 is_valid_ref_name(const char *name)
236 {
237 	const char *s, *slash, *seg;
238 	const char forbidden[] = { ' ', '~', '^', ':', '?', '*', '[' , '\\' };
239 	const char *forbidden_seq[] = { "//", "..", "@{" };
240 	const char *lfs = GOT_LOCKFILE_SUFFIX;
241 	const size_t lfs_len = sizeof(GOT_LOCKFILE_SUFFIX) - 1;
242 	int i;
243 
244 	if (name[0] == '@' && name[1] == '\0')
245 		return 0;
246 
247 	slash = strchr(name, '/');
248 	if (slash == NULL)
249 		return 0;
250 
251 	s = name;
252 	seg = s;
253 	if (seg[0] == '\0' || seg[0] == '.' || seg[0] == '/')
254 		return 0;
255 	while (*s) {
256 		for (i = 0; i < nitems(forbidden); i++) {
257 			if (*s == forbidden[i])
258 				return 0;
259 		}
260 		for (i = 0; i < nitems(forbidden_seq); i++) {
261 			if (s[0] == forbidden_seq[i][0] &&
262 			    s[1] == forbidden_seq[i][1])
263 				return 0;
264 		}
265 		if (iscntrl((unsigned char)s[0]))
266 			return 0;
267 		if (s[0] == '.' && s[1] == '\0')
268 			return 0;
269 		if (*s == '/') {
270 			const char *nextseg = s + 1;
271 			if (nextseg[0] == '\0' || nextseg[0] == '.' ||
272 			    nextseg[0] == '/')
273 				return 0;
274 			if (seg <= s - lfs_len &&
275 			    strncmp(s - lfs_len, lfs, lfs_len) == 0)
276 				return 0;
277 			seg = nextseg;
278 		}
279 		s++;
280 	}
281 
282 	if (seg <= s - lfs_len &&
283 	    strncmp(s - lfs_len, lfs, lfs_len) == 0)
284 		return 0;
285 
286 	return 1;
287 }
288 
289 const struct got_error *
290 got_ref_alloc(struct got_reference **ref, const char *name,
291     struct got_object_id *id)
292 {
293 	const struct got_error *err;
294 	char *absname = NULL;
295 
296 	if (!is_valid_ref_name(name)) {
297 		if (strchr(name, '/') != NULL)
298 			return got_error(GOT_ERR_BAD_REF_NAME);
299 		if (asprintf(&absname, "refs/heads/%s", name) == -1)
300 			return got_error_from_errno("asprintf");
301 	}
302 
303 	err = alloc_ref(ref, absname ? absname : name, id, 0);
304 	free(absname);
305 	return err;
306 }
307 
308 static const struct got_error *
309 parse_packed_ref_line(struct got_reference **ref, const char *abs_refname,
310     const char *line)
311 {
312 	struct got_object_id id;
313 	const char *name;
314 
315 	*ref = NULL;
316 
317 	if (line[0] == '#' || line[0] == '^')
318 		return NULL;
319 
320 	if (!got_parse_sha1_digest(id.sha1, line))
321 		return got_error(GOT_ERR_BAD_REF_DATA);
322 
323 	if (abs_refname) {
324 		if (strcmp(line + SHA1_DIGEST_STRING_LENGTH, abs_refname) != 0)
325 			return NULL;
326 		name = abs_refname;
327 	} else
328 		name = line + SHA1_DIGEST_STRING_LENGTH;
329 
330 	return alloc_ref(ref, name, &id, GOT_REF_IS_PACKED);
331 }
332 
333 static const struct got_error *
334 open_packed_ref(struct got_reference **ref, FILE *f, const char **subdirs,
335     int nsubdirs, const char *refname)
336 {
337 	const struct got_error *err = NULL;
338 	char *abs_refname;
339 	char *line;
340 	size_t len;
341 	const char delim[3] = {'\0', '\0', '\0'};
342 	int i, ref_is_absolute = (strncmp(refname, "refs/", 5) == 0);
343 
344 	*ref = NULL;
345 
346 	if (ref_is_absolute)
347 		abs_refname = (char *)refname;
348 	do {
349 		line = fparseln(f, &len, NULL, delim, 0);
350 		if (line == NULL) {
351 			if (feof(f))
352 				break;
353 			err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
354 			break;
355 		}
356 		for (i = 0; i < nsubdirs; i++) {
357 			if (!ref_is_absolute &&
358 			    asprintf(&abs_refname, "refs/%s/%s", subdirs[i],
359 			    refname) == -1)
360 				return got_error_from_errno("asprintf");
361 			err = parse_packed_ref_line(ref, abs_refname, line);
362 			if (!ref_is_absolute)
363 				free(abs_refname);
364 			if (err || *ref != NULL)
365 				break;
366 		}
367 		free(line);
368 		if (err)
369 			break;
370 	} while (*ref == NULL);
371 
372 	return err;
373 }
374 
375 static const struct got_error *
376 open_ref(struct got_reference **ref, const char *path_refs, const char *subdir,
377     const char *name, int lock)
378 {
379 	const struct got_error *err = NULL;
380 	char *path = NULL;
381 	char *normpath = NULL;
382 	char *absname = NULL;
383 	int ref_is_absolute = (strncmp(name, "refs/", 5) == 0);
384 	int ref_is_well_known = is_well_known_ref(name);
385 
386 	*ref = NULL;
387 
388 	if (ref_is_absolute || ref_is_well_known) {
389 		if (asprintf(&path, "%s/%s", path_refs, name) == -1)
390 			return got_error_from_errno("asprintf");
391 		absname = (char *)name;
392 	} else {
393 		if (asprintf(&path, "%s/%s%s%s", path_refs, subdir,
394 		    subdir[0] ? "/" : "", name) == -1)
395 			return got_error_from_errno("asprintf");
396 
397 		if (asprintf(&absname, "refs/%s%s%s",
398 		    subdir, subdir[0] ? "/" : "", name) == -1) {
399 			err = got_error_from_errno("asprintf");
400 			goto done;
401 		}
402 	}
403 
404 	normpath = got_path_normalize(path);
405 	if (normpath == NULL) {
406 		if (errno == ENOENT)
407 			err = NULL;
408 		else
409 			err = got_error_from_errno2("got_path_normalize", path);
410 		goto done;
411 	}
412 
413 	err = parse_ref_file(ref, absname, normpath, lock);
414 done:
415 	if (!ref_is_absolute && !ref_is_well_known)
416 		free(absname);
417 	free(path);
418 	free(normpath);
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
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 static const struct got_error *
539 resolve_symbolic_ref(struct got_reference **resolved,
540     struct got_repository *repo, struct got_reference *ref)
541 {
542 	struct got_reference *nextref;
543 	const struct got_error *err;
544 
545 	err = got_ref_open(&nextref, repo, ref->ref.symref.ref, 0);
546 	if (err)
547 		return err;
548 
549 	if (nextref->flags & GOT_REF_IS_SYMBOLIC)
550 		err = resolve_symbolic_ref(resolved, repo, nextref);
551 	else
552 		*resolved = got_ref_dup(nextref);
553 
554 	got_ref_close(nextref);
555 	return err;
556 }
557 
558 const struct got_error *
559 got_ref_resolve(struct got_object_id **id, struct got_repository *repo,
560     struct got_reference *ref)
561 {
562 	const struct got_error *err;
563 
564 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
565 		struct got_reference *resolved = NULL;
566 		err = resolve_symbolic_ref(&resolved, repo, ref);
567 		if (err == NULL)
568 			err = got_ref_resolve(id, repo, resolved);
569 		if (resolved)
570 			got_ref_close(resolved);
571 		return err;
572 	}
573 
574 	*id = calloc(1, sizeof(**id));
575 	if (*id == NULL)
576 		return got_error_from_errno("calloc");
577 	memcpy((*id)->sha1, ref->ref.ref.sha1, sizeof((*id)->sha1));
578 	return NULL;
579 }
580 
581 char *
582 got_ref_to_str(struct got_reference *ref)
583 {
584 	char *str;
585 
586 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
587 		return strdup(ref->ref.symref.ref);
588 
589 	str = malloc(SHA1_DIGEST_STRING_LENGTH);
590 	if (str == NULL)
591 		return NULL;
592 
593 	if (got_sha1_digest_to_str(ref->ref.ref.sha1, str,
594 	    SHA1_DIGEST_STRING_LENGTH) == NULL) {
595 		free(str);
596 		return NULL;
597 	}
598 
599 	return str;
600 }
601 
602 const char *
603 got_ref_get_name(struct got_reference *ref)
604 {
605 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
606 		return ref->ref.symref.name;
607 
608 	return ref->ref.ref.name;
609 }
610 
611 static const struct got_error *
612 insert_ref(struct got_reflist_entry **newp, struct got_reflist_head *refs,
613     struct got_reference *ref, struct got_repository *repo)
614 {
615 	const struct got_error *err;
616 	struct got_object_id *id;
617 	struct got_reflist_entry *new, *re, *prev = NULL;
618 	int cmp;
619 
620 	*newp = NULL;
621 
622 	err = got_ref_resolve(&id, repo, ref);
623 	if (err)
624 		return err;
625 
626 	new = malloc(sizeof(*new));
627 	if (new == NULL) {
628 		free(id);
629 		return got_error_from_errno("malloc");
630 	}
631 	new->ref = ref;
632 	new->id = id;
633 	*newp = new;
634 
635 	/*
636 	 * We must de-duplicate entries on insert because packed-refs may
637 	 * contain redundant entries. On-disk refs take precedence.
638 	 * This code assumes that on-disk revs are read before packed-refs.
639 	 * We're iterating the list anyway, so insert elements sorted by name.
640 	 */
641 	re = SIMPLEQ_FIRST(refs);
642 	while (re) {
643 		cmp = got_path_cmp(got_ref_get_name(re->ref),
644 		    got_ref_get_name(new->ref));
645 		if (cmp == 0) {
646 			/* duplicate */
647 			free(new->id);
648 			free(new);
649 			*newp = NULL;
650 			return NULL;
651 		} else if (cmp > 0) {
652 			if (prev)
653 				SIMPLEQ_INSERT_AFTER(refs, prev, new, entry);
654 			else
655 				SIMPLEQ_INSERT_HEAD(refs, new, entry);
656 			return NULL;
657 		} else {
658 			prev = re;
659 			re = SIMPLEQ_NEXT(re, entry);
660 		}
661 	}
662 
663 	SIMPLEQ_INSERT_TAIL(refs, new, entry);
664 	return NULL;
665 }
666 
667 static const struct got_error *
668 gather_on_disk_refs(struct got_reflist_head *refs, const char *path_refs,
669     const char *subdir, struct got_repository *repo)
670 {
671 	const struct got_error *err = NULL;
672 	DIR *d = NULL;
673 	char *path_subdir;
674 
675 	if (asprintf(&path_subdir, "%s/%s", path_refs, subdir) == -1)
676 		return got_error_from_errno("asprintf");
677 
678 	d = opendir(path_subdir);
679 	if (d == NULL)
680 		goto done;
681 
682 	for (;;) {
683 		struct dirent *dent;
684 		struct got_reference *ref;
685 		char *child;
686 
687 		dent = readdir(d);
688 		if (dent == NULL)
689 			break;
690 
691 		if (strcmp(dent->d_name, ".") == 0 ||
692 		    strcmp(dent->d_name, "..") == 0)
693 			continue;
694 
695 		switch (dent->d_type) {
696 		case DT_REG:
697 			err = open_ref(&ref, path_refs, subdir, dent->d_name,
698 			    0);
699 			if (err)
700 				goto done;
701 			if (ref) {
702 				struct got_reflist_entry *new;
703 				err = insert_ref(&new, refs, ref, repo);
704 				if (err || new == NULL /* duplicate */)
705 					got_ref_close(ref);
706 				if (err)
707 					goto done;
708 			}
709 			break;
710 		case DT_DIR:
711 			if (asprintf(&child, "%s%s%s", subdir,
712 			    subdir[0] == '\0' ? "" : "/", dent->d_name) == -1) {
713 				err = got_error_from_errno("asprintf");
714 				break;
715 			}
716 			err = gather_on_disk_refs(refs, path_refs, child, repo);
717 			free(child);
718 			break;
719 		default:
720 			break;
721 		}
722 	}
723 done:
724 	if (d)
725 		closedir(d);
726 	free(path_subdir);
727 	return err;
728 }
729 
730 const struct got_error *
731 got_ref_list(struct got_reflist_head *refs, struct got_repository *repo)
732 {
733 	const struct got_error *err;
734 	char *packed_refs_path, *path_refs = NULL;
735 	FILE *f = NULL;
736 	struct got_reference *ref;
737 	struct got_reflist_entry *new;
738 
739 	/* HEAD ref should always exist. */
740 	path_refs = get_refs_dir_path(repo, GOT_REF_HEAD);
741 	if (path_refs == NULL) {
742 		err = got_error_from_errno("get_refs_dir_path");
743 		goto done;
744 	}
745 	err = open_ref(&ref, path_refs, "", GOT_REF_HEAD, 0);
746 	if (err)
747 		goto done;
748 	err = insert_ref(&new, refs, ref, repo);
749 	if (err || new == NULL /* duplicate */)
750 		got_ref_close(ref);
751 	if (err)
752 		goto done;
753 
754 	/* Gather on-disk refs before parsing packed-refs. */
755 	free(path_refs);
756 	path_refs = get_refs_dir_path(repo, "");
757 	if (path_refs == NULL) {
758 		err = got_error_from_errno("get_refs_dir_path");
759 		goto done;
760 	}
761 	err = gather_on_disk_refs(refs, path_refs, "", repo);
762 	if (err)
763 		goto done;
764 
765 	/*
766 	 * The packed-refs file may contain redundant entries, in which
767 	 * case on-disk refs take precedence.
768 	 */
769 	packed_refs_path = got_repo_get_path_packed_refs(repo);
770 	if (packed_refs_path == NULL) {
771 		err = got_error_from_errno("got_repo_get_path_packed_refs");
772 		goto done;
773 	}
774 
775 	f = fopen(packed_refs_path, "r");
776 	free(packed_refs_path);
777 	if (f) {
778 		char *line;
779 		size_t len;
780 		const char delim[3] = {'\0', '\0', '\0'};
781 		for (;;) {
782 			line = fparseln(f, &len, NULL, delim, 0);
783 			if (line == NULL) {
784 				if (feof(f))
785 					break;
786 				err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
787 				goto done;
788 			}
789 			err = parse_packed_ref_line(&ref, NULL, line);
790 			free(line);
791 			if (err)
792 				goto done;
793 			if (ref) {
794 				err = insert_ref(&new, refs, ref, repo);
795 				if (err || new == NULL /* duplicate */)
796 					got_ref_close(ref);
797 				if (err)
798 					goto done;
799 			}
800 		}
801 	}
802 done:
803 	free(path_refs);
804 	if (f && fclose(f) != 0 && err == NULL)
805 		err = got_error_from_errno("fclose");
806 	return err;
807 }
808 
809 void
810 got_ref_list_free(struct got_reflist_head *refs)
811 {
812 	struct got_reflist_entry *re;
813 
814 	while (!SIMPLEQ_EMPTY(refs)) {
815 		re = SIMPLEQ_FIRST(refs);
816 		SIMPLEQ_REMOVE_HEAD(refs, entry);
817 		got_ref_close(re->ref);
818 		free(re->id);
819 		free(re);
820 	}
821 
822 }
823 
824 int
825 got_ref_is_symbolic(struct got_reference *ref)
826 {
827 	return (ref->flags & GOT_REF_IS_SYMBOLIC);
828 }
829 
830 const struct got_error *
831 got_ref_change_ref(struct got_reference *ref, struct got_object_id *id)
832 {
833 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
834 		return got_error(GOT_ERR_BAD_REF_TYPE);
835 
836 	memcpy(ref->ref.ref.sha1, id->sha1, sizeof(ref->ref.ref.sha1));
837 	return NULL;
838 }
839 
840 const struct got_error *
841 got_ref_change_symref(struct got_reference *ref, char *refname)
842 {
843 	char *new_name;
844 
845 	if ((ref->flags & GOT_REF_IS_SYMBOLIC) == 0)
846 		return got_error(GOT_ERR_BAD_REF_TYPE);
847 
848 	new_name = strdup(refname);
849 	if (new_name == NULL)
850 		return got_error_from_errno("strdup");
851 
852 	free(ref->ref.symref.name);
853 	ref->ref.symref.name = new_name;
854 	return NULL;
855 }
856 
857 const struct got_error *
858 got_ref_write(struct got_reference *ref, struct got_repository *repo)
859 {
860 	const struct got_error *err = NULL, *unlock_err = NULL;
861 	const char *name = got_ref_get_name(ref);
862 	char *path_refs = NULL, *path = NULL, *tmppath = NULL;
863 	struct got_lockfile *lf = NULL;
864 	FILE *f = NULL;
865 	size_t n;
866 	struct stat sb;
867 
868 	path_refs = get_refs_dir_path(repo, name);
869 	if (path_refs == NULL) {
870 		err = got_error_from_errno2("get_refs_dir_path", name);
871 		goto done;
872 	}
873 
874 	if (asprintf(&path, "%s/%s", path_refs, name) == -1) {
875 		err = got_error_from_errno("asprintf");
876 		goto done;
877 	}
878 
879 	err = got_opentemp_named(&tmppath, &f, path);
880 	if (err) {
881 		char *parent;
882 		if (!(err->code == GOT_ERR_ERRNO && errno == ENOENT))
883 			goto done;
884 		err = got_path_dirname(&parent, path);
885 		if (err)
886 			goto done;
887 		err = got_path_mkdir(parent);
888 		free(parent);
889 		if (err)
890 			goto done;
891 		err = got_opentemp_named(&tmppath, &f, path);
892 		if (err)
893 			goto done;
894 	}
895 
896 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
897 		n = fprintf(f, "ref: %s\n", ref->ref.symref.ref);
898 		if (n != strlen(ref->ref.symref.ref) + 6) {
899 			err = got_ferror(f, GOT_ERR_IO);
900 			goto done;
901 		}
902 	} else {
903 		char hex[SHA1_DIGEST_STRING_LENGTH];
904 		if (got_sha1_digest_to_str(ref->ref.ref.sha1, hex,
905 		    sizeof(hex)) == NULL) {
906 			err = got_error(GOT_ERR_BAD_REF_DATA);
907 			goto done;
908 		}
909 		n = fprintf(f, "%s\n", hex);
910 		if (n != sizeof(hex)) {
911 			err = got_ferror(f, GOT_ERR_IO);
912 			goto done;
913 		}
914 	}
915 
916 	if (ref->lf == NULL) {
917 		err = got_lockfile_lock(&lf, path);
918 		if (err)
919 			goto done;
920 	}
921 
922 	/* XXX: check if old content matches our expectations? */
923 
924 	if (stat(path, &sb) != 0) {
925 		if (errno != ENOENT) {
926 			err = got_error_from_errno2("stat", path);
927 			goto done;
928 		}
929 		sb.st_mode = GOT_DEFAULT_FILE_MODE;
930 	}
931 
932 	if (rename(tmppath, path) != 0) {
933 		err = got_error_from_errno3("rename", tmppath, path);
934 		goto done;
935 	}
936 	free(tmppath);
937 	tmppath = NULL;
938 
939 	if (chmod(path, sb.st_mode) != 0) {
940 		err = got_error_from_errno2("chmod", path);
941 		goto done;
942 	}
943 done:
944 	if (ref->lf == NULL && lf)
945 		unlock_err = got_lockfile_unlock(lf);
946 	if (f) {
947 		if (fclose(f) != 0 && err == NULL)
948 			err = got_error_from_errno("fclose");
949 	}
950 	free(path_refs);
951 	free(path);
952 	if (tmppath) {
953 		if (unlink(tmppath) != 0 && err == NULL)
954 			err = got_error_from_errno2("unlink", tmppath);
955 		free(tmppath);
956 	}
957 	return err ? err : unlock_err;
958 }
959 
960 static const struct got_error *
961 delete_packed_ref(struct got_reference *delref, struct got_repository *repo)
962 {
963 	const struct got_error *err = NULL, *unlock_err = NULL;
964 	struct got_lockfile *lf = NULL;
965 	FILE *f = NULL, *tmpf = NULL;
966 	char *packed_refs_path, *tmppath = NULL;
967 	struct got_reflist_head refs;
968 	int found_delref = 0;
969 
970 	/* The packed-refs file does not cotain symbolic references. */
971 	if (delref->flags & GOT_REF_IS_SYMBOLIC)
972 		return got_error(GOT_ERR_BAD_REF_DATA);
973 
974 	SIMPLEQ_INIT(&refs);
975 
976 	packed_refs_path = got_repo_get_path_packed_refs(repo);
977 	if (packed_refs_path == NULL)
978 		return got_error_from_errno("got_repo_get_path_packed_refs");
979 
980 	err = got_opentemp_named(&tmppath, &tmpf, packed_refs_path);
981 	if (err)
982 		goto done;
983 
984 	if (delref->lf == NULL) {
985 		err = got_lockfile_lock(&lf, packed_refs_path);
986 		if (err)
987 			goto done;
988 	}
989 
990 	f = fopen(packed_refs_path, "r");
991 	if (f == NULL) {
992 		err = got_error_from_errno2("fopen", packed_refs_path);
993 		goto done;
994 	}
995 	for (;;) {
996 		char *line;
997 		size_t len;
998 		const char delim[3] = {'\0', '\0', '\0'};
999 		struct got_reference *ref;
1000 		struct got_reflist_entry *new;
1001 
1002 		line = fparseln(f, &len, NULL, delim, 0);
1003 		if (line == NULL) {
1004 			if (feof(f))
1005 				break;
1006 			err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
1007 			goto done;
1008 		}
1009 		err = parse_packed_ref_line(&ref, NULL, line);
1010 		free(line);
1011 		if (err)
1012 			goto done;
1013 		if (ref == NULL)
1014 			continue;
1015 
1016 		if (strcmp(ref->ref.ref.name, delref->ref.ref.name) == 0 &&
1017 		    memcmp(ref->ref.ref.sha1, delref->ref.ref.sha1,
1018 		    sizeof(delref->ref.ref.sha1)) == 0) {
1019 			found_delref = 1;
1020 			got_ref_close(ref);
1021 			continue;
1022 		}
1023 
1024 		err = insert_ref(&new, &refs, ref, repo);
1025 		if (err || new == NULL /* duplicate */)
1026 			got_ref_close(ref);
1027 		if (err)
1028 			goto done;
1029 	}
1030 
1031 	if (found_delref) {
1032 		struct got_reflist_entry *re;
1033 		size_t n;
1034 		struct stat sb;
1035 
1036 		n = fprintf(tmpf, "%s\n", GOT_PACKED_REFS_HEADER);
1037 		if (n != sizeof(GOT_PACKED_REFS_HEADER)) {
1038 			err = got_ferror(f, GOT_ERR_IO);
1039 			goto done;
1040 		}
1041 
1042 		SIMPLEQ_FOREACH(re, &refs, entry) {
1043 			uint8_t hex[SHA1_DIGEST_STRING_LENGTH];
1044 
1045 			if (got_sha1_digest_to_str(re->ref->ref.ref.sha1, hex,
1046 			    sizeof(hex)) == NULL) {
1047 				err = got_error(GOT_ERR_BAD_REF_DATA);
1048 				goto done;
1049 			}
1050 			n = fprintf(tmpf, "%s ", hex);
1051 			if (n != sizeof(hex)) {
1052 				err = got_ferror(f, GOT_ERR_IO);
1053 				goto done;
1054 			}
1055 			n = fprintf(tmpf, "%s\n", re->ref->ref.ref.name);
1056 			if (n != strlen(re->ref->ref.ref.name) + 1) {
1057 				err = got_ferror(f, GOT_ERR_IO);
1058 				goto done;
1059 			}
1060 		}
1061 
1062 		if (fflush(tmpf) != 0) {
1063 			err = got_error_from_errno("fflush");
1064 			goto done;
1065 		}
1066 
1067 		if (stat(packed_refs_path, &sb) != 0) {
1068 			if (errno != ENOENT) {
1069 				err = got_error_from_errno2("stat",
1070 				    packed_refs_path);
1071 				goto done;
1072 			}
1073 			sb.st_mode = GOT_DEFAULT_FILE_MODE;
1074 		}
1075 
1076 		if (rename(tmppath, packed_refs_path) != 0) {
1077 			err = got_error_from_errno3("rename", tmppath,
1078 			    packed_refs_path);
1079 			goto done;
1080 		}
1081 
1082 		if (chmod(packed_refs_path, sb.st_mode) != 0) {
1083 			err = got_error_from_errno2("chmod",
1084 			    packed_refs_path);
1085 			goto done;
1086 		}
1087 	}
1088 done:
1089 	if (delref->lf == NULL && lf)
1090 		unlock_err = got_lockfile_unlock(lf);
1091 	if (f) {
1092 		if (fclose(f) != 0 && err == NULL)
1093 			err = got_error_from_errno("fclose");
1094 	}
1095 	if (tmpf) {
1096 		unlink(tmppath);
1097 		if (fclose(tmpf) != 0 && err == NULL)
1098 			err = got_error_from_errno("fclose");
1099 	}
1100 	free(tmppath);
1101 	free(packed_refs_path);
1102 	got_ref_list_free(&refs);
1103 	return err ? err : unlock_err;
1104 }
1105 
1106 const struct got_error *
1107 got_ref_delete(struct got_reference *ref, struct got_repository *repo)
1108 {
1109 	const struct got_error *err = NULL, *unlock_err = NULL;
1110 	const char *name = got_ref_get_name(ref);
1111 	char *path_refs = NULL, *path = NULL;
1112 	struct got_lockfile *lf = NULL;
1113 
1114 	if (ref->flags & GOT_REF_IS_PACKED)
1115 		return delete_packed_ref(ref, repo);
1116 
1117 	path_refs = get_refs_dir_path(repo, name);
1118 	if (path_refs == NULL) {
1119 		err = got_error_from_errno2("get_refs_dir_path", name);
1120 		goto done;
1121 	}
1122 
1123 	if (asprintf(&path, "%s/%s", path_refs, name) == -1) {
1124 		err = got_error_from_errno("asprintf");
1125 		goto done;
1126 	}
1127 
1128 	if (ref->lf == NULL) {
1129 		err = got_lockfile_lock(&lf, path);
1130 		if (err)
1131 			goto done;
1132 	}
1133 
1134 	/* XXX: check if old content matches our expectations? */
1135 
1136 	if (unlink(path) != 0)
1137 		err = got_error_from_errno2("unlink", path);
1138 done:
1139 	if (ref->lf == NULL && lf)
1140 		unlock_err = got_lockfile_unlock(lf);
1141 
1142 	free(path_refs);
1143 	free(path);
1144 	return err ? err : unlock_err;
1145 }
1146 
1147 const struct got_error *
1148 got_ref_unlock(struct got_reference *ref)
1149 {
1150 	const struct got_error *err;
1151 	err = got_lockfile_unlock(ref->lf);
1152 	ref->lf = NULL;
1153 	return err;
1154 }