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Date:: Fri Aug 2 13:42:42 2019 UTC
Message:: eliminate strlen() calls during fileindex rb tree searches
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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 	if (!is_valid_ref_name(name))
294 		return got_error(GOT_ERR_BAD_REF_NAME);
295 
296 	return alloc_ref(ref, name, id, 0);
297 }
298 
299 const struct got_error *
300 got_ref_alloc_symref(struct got_reference **ref, const char *name,
301 	struct got_reference *target_ref)
302 {
303 	if (!is_valid_ref_name(name))
304 		return got_error(GOT_ERR_BAD_REF_NAME);
305 
306 	return alloc_symref(ref, name, got_ref_get_name(target_ref), 0);
307 }
308 
309 static const struct got_error *
310 parse_packed_ref_line(struct got_reference **ref, const char *abs_refname,
311     const char *line)
312 {
313 	struct got_object_id id;
314 	const char *name;
315 
316 	*ref = NULL;
317 
318 	if (line[0] == '#' || line[0] == '^')
319 		return NULL;
320 
321 	if (!got_parse_sha1_digest(id.sha1, line))
322 		return got_error(GOT_ERR_BAD_REF_DATA);
323 
324 	if (abs_refname) {
325 		if (strcmp(line + SHA1_DIGEST_STRING_LENGTH, abs_refname) != 0)
326 			return NULL;
327 		name = abs_refname;
328 	} else
329 		name = line + SHA1_DIGEST_STRING_LENGTH;
330 
331 	return alloc_ref(ref, name, &id, GOT_REF_IS_PACKED);
332 }
333 
334 static const struct got_error *
335 open_packed_ref(struct got_reference **ref, FILE *f, const char **subdirs,
336     int nsubdirs, const char *refname)
337 {
338 	const struct got_error *err = NULL;
339 	char *abs_refname;
340 	char *line;
341 	size_t len;
342 	const char delim[3] = {'\0', '\0', '\0'};
343 	int i, ref_is_absolute = (strncmp(refname, "refs/", 5) == 0);
344 
345 	*ref = NULL;
346 
347 	if (ref_is_absolute)
348 		abs_refname = (char *)refname;
349 	do {
350 		line = fparseln(f, &len, NULL, delim, 0);
351 		if (line == NULL) {
352 			if (feof(f))
353 				break;
354 			err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
355 			break;
356 		}
357 		for (i = 0; i < nsubdirs; i++) {
358 			if (!ref_is_absolute &&
359 			    asprintf(&abs_refname, "refs/%s/%s", subdirs[i],
360 			    refname) == -1)
361 				return got_error_from_errno("asprintf");
362 			err = parse_packed_ref_line(ref, abs_refname, line);
363 			if (!ref_is_absolute)
364 				free(abs_refname);
365 			if (err || *ref != NULL)
366 				break;
367 		}
368 		free(line);
369 		if (err)
370 			break;
371 	} while (*ref == NULL);
372 
373 	return err;
374 }
375 
376 static const struct got_error *
377 open_ref(struct got_reference **ref, const char *path_refs, const char *subdir,
378     const char *name, int lock)
379 {
380 	const struct got_error *err = NULL;
381 	char *path = 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 	err = parse_ref_file(ref, absname, path, lock);
405 done:
406 	if (!ref_is_absolute && !ref_is_well_known)
407 		free(absname);
408 	free(path);
409 	return err;
410 }
411 
412 const struct got_error *
413 got_ref_open(struct got_reference **ref, struct got_repository *repo,
414    const char *refname, int lock)
415 {
416 	const struct got_error *err = NULL;
417 	char *path_refs = NULL;
418 	const char *subdirs[] = {
419 	    GOT_REF_HEADS, GOT_REF_TAGS, GOT_REF_REMOTES
420 	};
421 	int i, well_known = is_well_known_ref(refname);
422 	struct got_lockfile *lf = NULL;
423 
424 	*ref = NULL;
425 
426 	path_refs = get_refs_dir_path(repo, refname);
427 	if (path_refs == NULL) {
428 		err = got_error_from_errno2("get_refs_dir_path", refname);
429 		goto done;
430 	}
431 
432 	if (well_known) {
433 		err = open_ref(ref, path_refs, "", refname, lock);
434 	} else {
435 		char *packed_refs_path;
436 		FILE *f;
437 
438 		/* Search on-disk refs before packed refs! */
439 		for (i = 0; i < nitems(subdirs); i++) {
440 			err = open_ref(ref, path_refs, subdirs[i], refname,
441 			    lock);
442 			if (err || *ref)
443 				goto done;
444 		}
445 
446 		packed_refs_path = got_repo_get_path_packed_refs(repo);
447 		if (packed_refs_path == NULL) {
448 			err = got_error_from_errno(
449 			    "got_repo_get_path_packed_refs");
450 			goto done;
451 		}
452 
453 		if (lock) {
454 			err = got_lockfile_lock(&lf, packed_refs_path);
455 			if (err)
456 				goto done;
457 		}
458 		f = fopen(packed_refs_path, "rb");
459 		free(packed_refs_path);
460 		if (f != NULL) {
461 			err = open_packed_ref(ref, f, subdirs, nitems(subdirs),
462 			    refname);
463 			if (!err) {
464 				if (fclose(f) != 0) {
465 					err = got_error_from_errno("fclose");
466 					got_ref_close(*ref);
467 					*ref = NULL;
468 				} else if (*ref)
469 					(*ref)->lf = lf;
470 			}
471 		}
472 	}
473 done:
474 	if (!err && *ref == NULL)
475 		err = got_error_not_ref(refname);
476 	if (err && lf)
477 		got_lockfile_unlock(lf);
478 	free(path_refs);
479 	return err;
480 }
481 
482 void
483 got_ref_close(struct got_reference *ref)
484 {
485 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
486 		free(ref->ref.symref.name);
487 		free(ref->ref.symref.ref);
488 	} else
489 		free(ref->ref.ref.name);
490 	free(ref);
491 }
492 
493 struct got_reference *
494 got_ref_dup(struct got_reference *ref)
495 {
496 	struct got_reference *ret;
497 
498 	ret = calloc(1, sizeof(*ret));
499 	if (ret == NULL)
500 		return NULL;
501 
502 	ret->flags = ref->flags;
503 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
504 		ret->ref.symref.name = strdup(ref->ref.symref.name);
505 		if (ret->ref.symref.name == NULL) {
506 			free(ret);
507 			return NULL;
508 		}
509 		ret->ref.symref.ref = strdup(ref->ref.symref.ref);
510 		if (ret->ref.symref.ref == NULL) {
511 			free(ret->ref.symref.name);
512 			free(ret);
513 			return NULL;
514 		}
515 	} else {
516 		ref->ref.ref.name = strdup(ref->ref.ref.name);
517 		if (ref->ref.ref.name == NULL) {
518 			free(ret);
519 			return NULL;
520 		}
521 		memcpy(ret->ref.ref.sha1, ref->ref.ref.sha1,
522 		    sizeof(ret->ref.ref.sha1));
523 	}
524 
525 	return ret;
526 }
527 
528 static const struct got_error *
529 resolve_symbolic_ref(struct got_reference **resolved,
530     struct got_repository *repo, struct got_reference *ref)
531 {
532 	struct got_reference *nextref;
533 	const struct got_error *err;
534 
535 	err = got_ref_open(&nextref, repo, ref->ref.symref.ref, 0);
536 	if (err)
537 		return err;
538 
539 	if (nextref->flags & GOT_REF_IS_SYMBOLIC)
540 		err = resolve_symbolic_ref(resolved, repo, nextref);
541 	else
542 		*resolved = got_ref_dup(nextref);
543 
544 	got_ref_close(nextref);
545 	return err;
546 }
547 
548 const struct got_error *
549 got_ref_resolve(struct got_object_id **id, struct got_repository *repo,
550     struct got_reference *ref)
551 {
552 	const struct got_error *err;
553 
554 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
555 		struct got_reference *resolved = NULL;
556 		err = resolve_symbolic_ref(&resolved, repo, ref);
557 		if (err == NULL)
558 			err = got_ref_resolve(id, repo, resolved);
559 		if (resolved)
560 			got_ref_close(resolved);
561 		return err;
562 	}
563 
564 	*id = calloc(1, sizeof(**id));
565 	if (*id == NULL)
566 		return got_error_from_errno("calloc");
567 	memcpy((*id)->sha1, ref->ref.ref.sha1, sizeof((*id)->sha1));
568 	return NULL;
569 }
570 
571 char *
572 got_ref_to_str(struct got_reference *ref)
573 {
574 	char *str;
575 
576 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
577 		return strdup(ref->ref.symref.ref);
578 
579 	str = malloc(SHA1_DIGEST_STRING_LENGTH);
580 	if (str == NULL)
581 		return NULL;
582 
583 	if (got_sha1_digest_to_str(ref->ref.ref.sha1, str,
584 	    SHA1_DIGEST_STRING_LENGTH) == NULL) {
585 		free(str);
586 		return NULL;
587 	}
588 
589 	return str;
590 }
591 
592 const char *
593 got_ref_get_name(struct got_reference *ref)
594 {
595 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
596 		return ref->ref.symref.name;
597 
598 	return ref->ref.ref.name;
599 }
600 
601 const char *
602 got_ref_get_symref_target(struct got_reference *ref)
603 {
604 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
605 		return ref->ref.symref.ref;
606 
607 	return NULL;
608 }
609 
610 static const struct got_error *
611 insert_ref(struct got_reflist_entry **newp, struct got_reflist_head *refs,
612     struct got_reference *ref, struct got_repository *repo)
613 {
614 	const struct got_error *err;
615 	struct got_object_id *id;
616 	struct got_reflist_entry *new, *re, *prev = NULL;
617 	int cmp;
618 
619 	*newp = NULL;
620 
621 	err = got_ref_resolve(&id, repo, ref);
622 	if (err)
623 		return err;
624 
625 	new = malloc(sizeof(*new));
626 	if (new == NULL) {
627 		free(id);
628 		return got_error_from_errno("malloc");
629 	}
630 	new->ref = ref;
631 	new->id = id;
632 	*newp = new;
633 
634 	/*
635 	 * We must de-duplicate entries on insert because packed-refs may
636 	 * contain redundant entries. On-disk refs take precedence.
637 	 * This code assumes that on-disk revs are read before packed-refs.
638 	 * We're iterating the list anyway, so insert elements sorted by name.
639 	 */
640 	re = SIMPLEQ_FIRST(refs);
641 	while (re) {
642 		const char *name = got_ref_get_name(re->ref);
643 		const char *new_name = got_ref_get_name(new->ref);
644 		cmp = got_path_cmp(name, new_name, strlen(name),
645 		    strlen(new_name));
646 		if (cmp == 0) {
647 			/* duplicate */
648 			free(new->id);
649 			free(new);
650 			*newp = NULL;
651 			return NULL;
652 		} else if (cmp > 0) {
653 			if (prev)
654 				SIMPLEQ_INSERT_AFTER(refs, prev, new, entry);
655 			else
656 				SIMPLEQ_INSERT_HEAD(refs, new, entry);
657 			return NULL;
658 		} else {
659 			prev = re;
660 			re = SIMPLEQ_NEXT(re, entry);
661 		}
662 	}
663 
664 	SIMPLEQ_INSERT_TAIL(refs, new, entry);
665 	return NULL;
666 }
667 
668 static const struct got_error *
669 gather_on_disk_refs(struct got_reflist_head *refs, const char *path_refs,
670     const char *subdir, struct got_repository *repo)
671 {
672 	const struct got_error *err = NULL;
673 	DIR *d = NULL;
674 	char *path_subdir;
675 
676 	if (asprintf(&path_subdir, "%s/%s", path_refs, subdir) == -1)
677 		return got_error_from_errno("asprintf");
678 
679 	d = opendir(path_subdir);
680 	if (d == NULL)
681 		goto done;
682 
683 	for (;;) {
684 		struct dirent *dent;
685 		struct got_reference *ref;
686 		char *child;
687 
688 		dent = readdir(d);
689 		if (dent == NULL)
690 			break;
691 
692 		if (strcmp(dent->d_name, ".") == 0 ||
693 		    strcmp(dent->d_name, "..") == 0)
694 			continue;
695 
696 		switch (dent->d_type) {
697 		case DT_REG:
698 			err = open_ref(&ref, path_refs, subdir, dent->d_name,
699 			    0);
700 			if (err)
701 				goto done;
702 			if (ref) {
703 				struct got_reflist_entry *new;
704 				err = insert_ref(&new, refs, ref, repo);
705 				if (err || new == NULL /* duplicate */)
706 					got_ref_close(ref);
707 				if (err)
708 					goto done;
709 			}
710 			break;
711 		case DT_DIR:
712 			if (asprintf(&child, "%s%s%s", subdir,
713 			    subdir[0] == '\0' ? "" : "/", dent->d_name) == -1) {
714 				err = got_error_from_errno("asprintf");
715 				break;
716 			}
717 			err = gather_on_disk_refs(refs, path_refs, child, repo);
718 			free(child);
719 			break;
720 		default:
721 			break;
722 		}
723 	}
724 done:
725 	if (d)
726 		closedir(d);
727 	free(path_subdir);
728 	return err;
729 }
730 
731 const struct got_error *
732 got_ref_list(struct got_reflist_head *refs, struct got_repository *repo)
733 {
734 	const struct got_error *err;
735 	char *packed_refs_path, *path_refs = NULL;
736 	FILE *f = NULL;
737 	struct got_reference *ref;
738 	struct got_reflist_entry *new;
739 
740 	/* HEAD ref should always exist. */
741 	path_refs = get_refs_dir_path(repo, GOT_REF_HEAD);
742 	if (path_refs == NULL) {
743 		err = got_error_from_errno("get_refs_dir_path");
744 		goto done;
745 	}
746 	err = open_ref(&ref, path_refs, "", GOT_REF_HEAD, 0);
747 	if (err)
748 		goto done;
749 	err = insert_ref(&new, refs, ref, repo);
750 	if (err || new == NULL /* duplicate */)
751 		got_ref_close(ref);
752 	if (err)
753 		goto done;
754 
755 	/* Gather on-disk refs before parsing packed-refs. */
756 	free(path_refs);
757 	path_refs = get_refs_dir_path(repo, "");
758 	if (path_refs == NULL) {
759 		err = got_error_from_errno("get_refs_dir_path");
760 		goto done;
761 	}
762 	err = gather_on_disk_refs(refs, path_refs, "", repo);
763 	if (err)
764 		goto done;
765 
766 	/*
767 	 * The packed-refs file may contain redundant entries, in which
768 	 * case on-disk refs take precedence.
769 	 */
770 	packed_refs_path = got_repo_get_path_packed_refs(repo);
771 	if (packed_refs_path == NULL) {
772 		err = got_error_from_errno("got_repo_get_path_packed_refs");
773 		goto done;
774 	}
775 
776 	f = fopen(packed_refs_path, "r");
777 	free(packed_refs_path);
778 	if (f) {
779 		char *line;
780 		size_t len;
781 		const char delim[3] = {'\0', '\0', '\0'};
782 		for (;;) {
783 			line = fparseln(f, &len, NULL, delim, 0);
784 			if (line == NULL) {
785 				if (feof(f))
786 					break;
787 				err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
788 				goto done;
789 			}
790 			err = parse_packed_ref_line(&ref, NULL, line);
791 			free(line);
792 			if (err)
793 				goto done;
794 			if (ref) {
795 				err = insert_ref(&new, refs, ref, repo);
796 				if (err || new == NULL /* duplicate */)
797 					got_ref_close(ref);
798 				if (err)
799 					goto done;
800 			}
801 		}
802 	}
803 done:
804 	free(path_refs);
805 	if (f && fclose(f) != 0 && err == NULL)
806 		err = got_error_from_errno("fclose");
807 	return err;
808 }
809 
810 void
811 got_ref_list_free(struct got_reflist_head *refs)
812 {
813 	struct got_reflist_entry *re;
814 
815 	while (!SIMPLEQ_EMPTY(refs)) {
816 		re = SIMPLEQ_FIRST(refs);
817 		SIMPLEQ_REMOVE_HEAD(refs, entry);
818 		got_ref_close(re->ref);
819 		free(re->id);
820 		free(re);
821 	}
822 
823 }
824 
825 int
826 got_ref_is_symbolic(struct got_reference *ref)
827 {
828 	return (ref->flags & GOT_REF_IS_SYMBOLIC);
829 }
830 
831 const struct got_error *
832 got_ref_change_ref(struct got_reference *ref, struct got_object_id *id)
833 {
834 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
835 		return got_error(GOT_ERR_BAD_REF_TYPE);
836 
837 	memcpy(ref->ref.ref.sha1, id->sha1, sizeof(ref->ref.ref.sha1));
838 	return NULL;
839 }
840 
841 const struct got_error *
842 got_ref_change_symref(struct got_reference *ref, char *refname)
843 {
844 	char *new_name;
845 
846 	if ((ref->flags & GOT_REF_IS_SYMBOLIC) == 0)
847 		return got_error(GOT_ERR_BAD_REF_TYPE);
848 
849 	new_name = strdup(refname);
850 	if (new_name == NULL)
851 		return got_error_from_errno("strdup");
852 
853 	free(ref->ref.symref.name);
854 	ref->ref.symref.name = new_name;
855 	return NULL;
856 }
857 
858 const struct got_error *
859 got_ref_write(struct got_reference *ref, struct got_repository *repo)
860 {
861 	const struct got_error *err = NULL, *unlock_err = NULL;
862 	const char *name = got_ref_get_name(ref);
863 	char *path_refs = NULL, *path = NULL, *tmppath = NULL;
864 	struct got_lockfile *lf = NULL;
865 	FILE *f = NULL;
866 	size_t n;
867 	struct stat sb;
868 
869 	path_refs = get_refs_dir_path(repo, name);
870 	if (path_refs == NULL) {
871 		err = got_error_from_errno2("get_refs_dir_path", name);
872 		goto done;
873 	}
874 
875 	if (asprintf(&path, "%s/%s", path_refs, name) == -1) {
876 		err = got_error_from_errno("asprintf");
877 		goto done;
878 	}
879 
880 	err = got_opentemp_named(&tmppath, &f, path);
881 	if (err) {
882 		char *parent;
883 		if (!(err->code == GOT_ERR_ERRNO && errno == ENOENT))
884 			goto done;
885 		err = got_path_dirname(&parent, path);
886 		if (err)
887 			goto done;
888 		err = got_path_mkdir(parent);
889 		free(parent);
890 		if (err)
891 			goto done;
892 		err = got_opentemp_named(&tmppath, &f, path);
893 		if (err)
894 			goto done;
895 	}
896 
897 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
898 		n = fprintf(f, "ref: %s\n", ref->ref.symref.ref);
899 		if (n != strlen(ref->ref.symref.ref) + 6) {
900 			err = got_ferror(f, GOT_ERR_IO);
901 			goto done;
902 		}
903 	} else {
904 		char hex[SHA1_DIGEST_STRING_LENGTH];
905 		if (got_sha1_digest_to_str(ref->ref.ref.sha1, hex,
906 		    sizeof(hex)) == NULL) {
907 			err = got_error(GOT_ERR_BAD_REF_DATA);
908 			goto done;
909 		}
910 		n = fprintf(f, "%s\n", hex);
911 		if (n != sizeof(hex)) {
912 			err = got_ferror(f, GOT_ERR_IO);
913 			goto done;
914 		}
915 	}
916 
917 	if (ref->lf == NULL) {
918 		err = got_lockfile_lock(&lf, path);
919 		if (err)
920 			goto done;
921 	}
922 
923 	/* XXX: check if old content matches our expectations? */
924 
925 	if (stat(path, &sb) != 0) {
926 		if (errno != ENOENT) {
927 			err = got_error_from_errno2("stat", path);
928 			goto done;
929 		}
930 		sb.st_mode = GOT_DEFAULT_FILE_MODE;
931 	}
932 
933 	if (rename(tmppath, path) != 0) {
934 		err = got_error_from_errno3("rename", tmppath, path);
935 		goto done;
936 	}
937 	free(tmppath);
938 	tmppath = NULL;
939 
940 	if (chmod(path, sb.st_mode) != 0) {
941 		err = got_error_from_errno2("chmod", path);
942 		goto done;
943 	}
944 done:
945 	if (ref->lf == NULL && lf)
946 		unlock_err = got_lockfile_unlock(lf);
947 	if (f) {
948 		if (fclose(f) != 0 && err == NULL)
949 			err = got_error_from_errno("fclose");
950 	}
951 	free(path_refs);
952 	free(path);
953 	if (tmppath) {
954 		if (unlink(tmppath) != 0 && err == NULL)
955 			err = got_error_from_errno2("unlink", tmppath);
956 		free(tmppath);
957 	}
958 	return err ? err : unlock_err;
959 }
960 
961 static const struct got_error *
962 delete_packed_ref(struct got_reference *delref, struct got_repository *repo)
963 {
964 	const struct got_error *err = NULL, *unlock_err = NULL;
965 	struct got_lockfile *lf = NULL;
966 	FILE *f = NULL, *tmpf = NULL;
967 	char *packed_refs_path, *tmppath = NULL;
968 	struct got_reflist_head refs;
969 	int found_delref = 0;
970 
971 	/* The packed-refs file does not cotain symbolic references. */
972 	if (delref->flags & GOT_REF_IS_SYMBOLIC)
973 		return got_error(GOT_ERR_BAD_REF_DATA);
974 
975 	SIMPLEQ_INIT(&refs);
976 
977 	packed_refs_path = got_repo_get_path_packed_refs(repo);
978 	if (packed_refs_path == NULL)
979 		return got_error_from_errno("got_repo_get_path_packed_refs");
980 
981 	err = got_opentemp_named(&tmppath, &tmpf, packed_refs_path);
982 	if (err)
983 		goto done;
984 
985 	if (delref->lf == NULL) {
986 		err = got_lockfile_lock(&lf, packed_refs_path);
987 		if (err)
988 			goto done;
989 	}
990 
991 	f = fopen(packed_refs_path, "r");
992 	if (f == NULL) {
993 		err = got_error_from_errno2("fopen", packed_refs_path);
994 		goto done;
995 	}
996 	for (;;) {
997 		char *line;
998 		size_t len;
999 		const char delim[3] = {'\0', '\0', '\0'};
1000 		struct got_reference *ref;
1001 		struct got_reflist_entry *new;
1002 
1003 		line = fparseln(f, &len, NULL, delim, 0);
1004 		if (line == NULL) {
1005 			if (feof(f))
1006 				break;
1007 			err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
1008 			goto done;
1009 		}
1010 		err = parse_packed_ref_line(&ref, NULL, line);
1011 		free(line);
1012 		if (err)
1013 			goto done;
1014 		if (ref == NULL)
1015 			continue;
1016 
1017 		if (strcmp(ref->ref.ref.name, delref->ref.ref.name) == 0 &&
1018 		    memcmp(ref->ref.ref.sha1, delref->ref.ref.sha1,
1019 		    sizeof(delref->ref.ref.sha1)) == 0) {
1020 			found_delref = 1;
1021 			got_ref_close(ref);
1022 			continue;
1023 		}
1024 
1025 		err = insert_ref(&new, &refs, ref, repo);
1026 		if (err || new == NULL /* duplicate */)
1027 			got_ref_close(ref);
1028 		if (err)
1029 			goto done;
1030 	}
1031 
1032 	if (found_delref) {
1033 		struct got_reflist_entry *re;
1034 		size_t n;
1035 		struct stat sb;
1036 
1037 		n = fprintf(tmpf, "%s\n", GOT_PACKED_REFS_HEADER);
1038 		if (n != sizeof(GOT_PACKED_REFS_HEADER)) {
1039 			err = got_ferror(f, GOT_ERR_IO);
1040 			goto done;
1041 		}
1042 
1043 		SIMPLEQ_FOREACH(re, &refs, entry) {
1044 			uint8_t hex[SHA1_DIGEST_STRING_LENGTH];
1045 
1046 			if (got_sha1_digest_to_str(re->ref->ref.ref.sha1, hex,
1047 			    sizeof(hex)) == NULL) {
1048 				err = got_error(GOT_ERR_BAD_REF_DATA);
1049 				goto done;
1050 			}
1051 			n = fprintf(tmpf, "%s ", hex);
1052 			if (n != sizeof(hex)) {
1053 				err = got_ferror(f, GOT_ERR_IO);
1054 				goto done;
1055 			}
1056 			n = fprintf(tmpf, "%s\n", re->ref->ref.ref.name);
1057 			if (n != strlen(re->ref->ref.ref.name) + 1) {
1058 				err = got_ferror(f, GOT_ERR_IO);
1059 				goto done;
1060 			}
1061 		}
1062 
1063 		if (fflush(tmpf) != 0) {
1064 			err = got_error_from_errno("fflush");
1065 			goto done;
1066 		}
1067 
1068 		if (stat(packed_refs_path, &sb) != 0) {
1069 			if (errno != ENOENT) {
1070 				err = got_error_from_errno2("stat",
1071 				    packed_refs_path);
1072 				goto done;
1073 			}
1074 			sb.st_mode = GOT_DEFAULT_FILE_MODE;
1075 		}
1076 
1077 		if (rename(tmppath, packed_refs_path) != 0) {
1078 			err = got_error_from_errno3("rename", tmppath,
1079 			    packed_refs_path);
1080 			goto done;
1081 		}
1082 
1083 		if (chmod(packed_refs_path, sb.st_mode) != 0) {
1084 			err = got_error_from_errno2("chmod",
1085 			    packed_refs_path);
1086 			goto done;
1087 		}
1088 	}
1089 done:
1090 	if (delref->lf == NULL && lf)
1091 		unlock_err = got_lockfile_unlock(lf);
1092 	if (f) {
1093 		if (fclose(f) != 0 && err == NULL)
1094 			err = got_error_from_errno("fclose");
1095 	}
1096 	if (tmpf) {
1097 		unlink(tmppath);
1098 		if (fclose(tmpf) != 0 && err == NULL)
1099 			err = got_error_from_errno("fclose");
1100 	}
1101 	free(tmppath);
1102 	free(packed_refs_path);
1103 	got_ref_list_free(&refs);
1104 	return err ? err : unlock_err;
1105 }
1106 
1107 const struct got_error *
1108 got_ref_delete(struct got_reference *ref, struct got_repository *repo)
1109 {
1110 	const struct got_error *err = NULL, *unlock_err = NULL;
1111 	const char *name = got_ref_get_name(ref);
1112 	char *path_refs = NULL, *path = NULL;
1113 	struct got_lockfile *lf = NULL;
1114 
1115 	if (ref->flags & GOT_REF_IS_PACKED)
1116 		return delete_packed_ref(ref, repo);
1117 
1118 	path_refs = get_refs_dir_path(repo, name);
1119 	if (path_refs == NULL) {
1120 		err = got_error_from_errno2("get_refs_dir_path", name);
1121 		goto done;
1122 	}
1123 
1124 	if (asprintf(&path, "%s/%s", path_refs, name) == -1) {
1125 		err = got_error_from_errno("asprintf");
1126 		goto done;
1127 	}
1128 
1129 	if (ref->lf == NULL) {
1130 		err = got_lockfile_lock(&lf, path);
1131 		if (err)
1132 			goto done;
1133 	}
1134 
1135 	/* XXX: check if old content matches our expectations? */
1136 
1137 	if (unlink(path) != 0)
1138 		err = got_error_from_errno2("unlink", path);
1139 done:
1140 	if (ref->lf == NULL && lf)
1141 		unlock_err = got_lockfile_unlock(lf);
1142 
1143 	free(path_refs);
1144 	free(path);
1145 	return err ? err : unlock_err;
1146 }
1147 
1148 const struct got_error *
1149 got_ref_unlock(struct got_reference *ref)
1150 {
1151 	const struct got_error *err;
1152 	err = got_lockfile_unlock(ref->lf);
1153 	ref->lf = NULL;
1154 	return err;
1155 }