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Date:: Thu Nov 26 12:54:19 2020 UTC
Message:: use size_t for loop indices to avoid signedness warnings; from emaste@freebsd
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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 <limits.h>
25 #include <sha1.h>
26 #include <stdio.h>
27 #include <stdlib.h>
28 #include <string.h>
29 #include <unistd.h>
30 #include <util.h>
31 #include <zlib.h>
32 #include <time.h>
33 #include <libgen.h>
34 
35 #include "got_error.h"
36 #include "got_object.h"
37 #include "got_repository.h"
38 #include "got_reference.h"
39 #include "got_opentemp.h"
40 #include "got_path.h"
41 
42 #include "got_lib_sha1.h"
43 #include "got_lib_delta.h"
44 #include "got_lib_inflate.h"
45 #include "got_lib_object.h"
46 #include "got_lib_lockfile.h"
47 
48 #ifndef nitems
49 #define nitems(_a) (sizeof(_a) / sizeof((_a)[0]))
50 #endif
51 
52 #define GOT_REF_HEADS	"heads"
53 #define GOT_REF_TAGS	"tags"
54 #define GOT_REF_REMOTES	"remotes"
55 
56 /*
57  * We do not resolve tags yet, and don't yet care about sorting refs either,
58  * so packed-refs files we write contain a minimal header which disables all
59  * packed-refs "traits" supported by Git.
60  */
61 #define GOT_PACKED_REFS_HEADER	"# pack-refs with:"
62 
63 /* A symbolic reference. */
64 struct got_symref {
65 	char *name;
66 	char *ref;
67 };
68 
69 #define GOT_REF_RECURSE_MAX	20
70 
71 /* A non-symbolic reference (there is no better designation). */
72 struct got_ref {
73 	char *name;
74 	u_int8_t sha1[SHA1_DIGEST_LENGTH];
75 };
76 
77 /* A reference which points to an arbitrary object. */
78 struct got_reference {
79 	unsigned int flags;
80 #define GOT_REF_IS_SYMBOLIC	0x01
81 #define GOT_REF_IS_PACKED	0x02
82 
83 	union {
84 		struct got_ref ref;
85 		struct got_symref symref;
86 	} ref;
87 
88 	struct got_lockfile *lf;
89 };
90 
91 static const struct got_error *
92 alloc_ref(struct got_reference **ref, const char *name,
93     struct got_object_id *id, int flags)
94 {
95 	const struct got_error *err = NULL;
96 
97 	*ref = calloc(1, sizeof(**ref));
98 	if (*ref == NULL)
99 		return got_error_from_errno("calloc");
100 
101 	memcpy((*ref)->ref.ref.sha1, id->sha1, sizeof((*ref)->ref.ref.sha1));
102 	(*ref)->flags = flags;
103 	(*ref)->ref.ref.name = strdup(name);
104 	if ((*ref)->ref.ref.name == NULL) {
105 		err = got_error_from_errno("strdup");
106 		got_ref_close(*ref);
107 		*ref = NULL;
108 	}
109 	return err;
110 }
111 
112 static const struct got_error *
113 alloc_symref(struct got_reference **ref, const char *name,
114     const char *target_ref, int flags)
115 {
116 	const struct got_error *err = NULL;
117 
118 	*ref = calloc(1, sizeof(**ref));
119 	if (*ref == NULL)
120 		return got_error_from_errno("calloc");
121 
122 	(*ref)->flags = GOT_REF_IS_SYMBOLIC | flags;
123 	(*ref)->ref.symref.name = strdup(name);
124 	if ((*ref)->ref.symref.name == NULL) {
125 		err = got_error_from_errno("strdup");
126 		got_ref_close(*ref);
127 		*ref = NULL;
128 		return err;
129 	}
130 	(*ref)->ref.symref.ref = strdup(target_ref);
131 	if ((*ref)->ref.symref.ref == NULL) {
132 		err = got_error_from_errno("strdup");
133 		got_ref_close(*ref);
134 		*ref = NULL;
135 	}
136 	return err;
137 }
138 
139 static const struct got_error *
140 parse_symref(struct got_reference **ref, const char *name, const char *line)
141 {
142 	if (line[0] == '\0')
143 		return got_error(GOT_ERR_BAD_REF_DATA);
144 
145 	return alloc_symref(ref, name, line, 0);
146 }
147 
148 static const struct got_error *
149 parse_ref_line(struct got_reference **ref, const char *name, const char *line)
150 {
151 	struct got_object_id id;
152 
153 	if (strncmp(line, "ref: ", 5) == 0) {
154 		line += 5;
155 		return parse_symref(ref, name, line);
156 	}
157 
158 	if (!got_parse_sha1_digest(id.sha1, line))
159 		return got_error(GOT_ERR_BAD_REF_DATA);
160 
161 	return alloc_ref(ref, name, &id, 0);
162 }
163 
164 static const struct got_error *
165 parse_ref_file(struct got_reference **ref, const char *name,
166     const char *absname, const char *abspath, int lock)
167 {
168 	const struct got_error *err = NULL;
169 	FILE *f;
170 	char *line = NULL;
171 	size_t linesize = 0;
172 	ssize_t linelen;
173 	struct got_lockfile *lf = NULL;
174 
175 	if (lock) {
176 		err = got_lockfile_lock(&lf, abspath);
177 		if (err) {
178 			if (err->code == GOT_ERR_ERRNO && errno == ENOENT)
179 				err = got_error_not_ref(name);
180 			return err;
181 		}
182 	}
183 
184 	f = fopen(abspath, "rb");
185 	if (f == NULL) {
186 		if (errno != ENOTDIR && errno != ENOENT)
187 			err = got_error_from_errno2("fopen", abspath);
188 		else
189 			err = got_error_not_ref(name);
190 		if (lock)
191 			got_lockfile_unlock(lf);
192 		return err;
193 	}
194 
195 	linelen = getline(&line, &linesize, f);
196 	if (linelen == -1) {
197 		if (feof(f))
198 			err = NULL; /* ignore empty files (could be locks) */
199 		else {
200 			if (errno == EISDIR)
201 				err = got_error(GOT_ERR_NOT_REF);
202 			else if (ferror(f))
203 				err = got_ferror(f, GOT_ERR_IO);
204 			else
205 				err = got_error_from_errno2("getline", abspath);
206 		}
207 		if (lock)
208 			got_lockfile_unlock(lf);
209 		goto done;
210 	}
211 	while (linelen > 0 && line[linelen - 1] == '\n') {
212 		line[linelen - 1] = '\0';
213 		linelen--;
214 	}
215 
216 	err = parse_ref_line(ref, absname, line);
217 	if (lock) {
218 		if (err)
219 			got_lockfile_unlock(lf);
220 		else {
221 			if (*ref)
222 				(*ref)->lf = lf;
223 			else
224 				got_lockfile_unlock(lf);
225 		}
226 	}
227 done:
228 	free(line);
229 	if (fclose(f) != 0 && err == NULL) {
230 		err = got_error_from_errno("fclose");
231 		if (*ref) {
232 			if (lock)
233 				got_ref_unlock(*ref);
234 			got_ref_close(*ref);
235 			*ref = NULL;
236 		}
237 	}
238 	return err;
239 }
240 
241 static int
242 is_well_known_ref(const char *refname)
243 {
244 	return (strcmp(refname, GOT_REF_HEAD) == 0 ||
245 	    strcmp(refname, GOT_REF_ORIG_HEAD) == 0 ||
246 	    strcmp(refname, GOT_REF_MERGE_HEAD) == 0 ||
247 	    strcmp(refname, GOT_REF_FETCH_HEAD) == 0);
248 }
249 
250 static char *
251 get_refs_dir_path(struct got_repository *repo, const char *refname)
252 {
253 	if (is_well_known_ref(refname) || strncmp(refname, "refs/", 5) == 0)
254 		return strdup(got_repo_get_path_git_dir(repo));
255 
256 	return got_repo_get_path_refs(repo);
257 }
258 
259 static int
260 is_valid_ref_name(const char *name)
261 {
262 	const char *s, *seg;
263 	const char forbidden[] = { ' ', '~', '^', ':', '?', '*', '[' , '\\' };
264 	const char *forbidden_seq[] = { "//", "..", "@{" };
265 	const char *lfs = GOT_LOCKFILE_SUFFIX;
266 	const size_t lfs_len = sizeof(GOT_LOCKFILE_SUFFIX) - 1;
267 	size_t i;
268 
269 	if (name[0] == '@' && name[1] == '\0')
270 		return 0;
271 
272 	s = name;
273 	seg = s;
274 	if (seg[0] == '\0' || seg[0] == '.' || seg[0] == '/')
275 		return 0;
276 	while (*s) {
277 		for (i = 0; i < nitems(forbidden); i++) {
278 			if (*s == forbidden[i])
279 				return 0;
280 		}
281 		for (i = 0; i < nitems(forbidden_seq); i++) {
282 			if (s[0] == forbidden_seq[i][0] &&
283 			    s[1] == forbidden_seq[i][1])
284 				return 0;
285 		}
286 		if (iscntrl((unsigned char)s[0]))
287 			return 0;
288 		if (s[0] == '.' && s[1] == '\0')
289 			return 0;
290 		if (*s == '/') {
291 			const char *nextseg = s + 1;
292 			if (nextseg[0] == '\0' || nextseg[0] == '.' ||
293 			    nextseg[0] == '/')
294 				return 0;
295 			if (seg <= s - lfs_len &&
296 			    strncmp(s - lfs_len, lfs, lfs_len) == 0)
297 				return 0;
298 			seg = nextseg;
299 		}
300 		s++;
301 	}
302 
303 	if (seg <= s - lfs_len &&
304 	    strncmp(s - lfs_len, lfs, lfs_len) == 0)
305 		return 0;
306 
307 	return 1;
308 }
309 
310 const struct got_error *
311 got_ref_alloc(struct got_reference **ref, const char *name,
312     struct got_object_id *id)
313 {
314 	if (!is_valid_ref_name(name))
315 		return got_error_path(name, GOT_ERR_BAD_REF_NAME);
316 
317 	return alloc_ref(ref, name, id, 0);
318 }
319 
320 const struct got_error *
321 got_ref_alloc_symref(struct got_reference **ref, const char *name,
322 	struct got_reference *target_ref)
323 {
324 	if (!is_valid_ref_name(name))
325 		return got_error_path(name, GOT_ERR_BAD_REF_NAME);
326 
327 	return alloc_symref(ref, name, got_ref_get_name(target_ref), 0);
328 }
329 
330 static const struct got_error *
331 parse_packed_ref_line(struct got_reference **ref, const char *abs_refname,
332     const char *line)
333 {
334 	struct got_object_id id;
335 	const char *name;
336 
337 	*ref = NULL;
338 
339 	if (line[0] == '#' || line[0] == '^')
340 		return NULL;
341 
342 	if (!got_parse_sha1_digest(id.sha1, line))
343 		return got_error(GOT_ERR_BAD_REF_DATA);
344 
345 	if (abs_refname) {
346 		if (strcmp(line + SHA1_DIGEST_STRING_LENGTH, abs_refname) != 0)
347 			return NULL;
348 		name = abs_refname;
349 	} else
350 		name = line + SHA1_DIGEST_STRING_LENGTH;
351 
352 	return alloc_ref(ref, name, &id, GOT_REF_IS_PACKED);
353 }
354 
355 static const struct got_error *
356 open_packed_ref(struct got_reference **ref, FILE *f, const char **subdirs,
357     int nsubdirs, const char *refname)
358 {
359 	const struct got_error *err = NULL;
360 	char *abs_refname;
361 	char *line;
362 	size_t len;
363 	const char delim[3] = {'\0', '\0', '\0'};
364 	int i, ref_is_absolute = (strncmp(refname, "refs/", 5) == 0);
365 
366 	*ref = NULL;
367 
368 	if (ref_is_absolute)
369 		abs_refname = (char *)refname;
370 	do {
371 		line = fparseln(f, &len, NULL, delim, 0);
372 		if (line == NULL) {
373 			if (feof(f))
374 				break;
375 			err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
376 			break;
377 		}
378 		for (i = 0; i < nsubdirs; i++) {
379 			if (!ref_is_absolute &&
380 			    asprintf(&abs_refname, "refs/%s/%s", subdirs[i],
381 			    refname) == -1)
382 				return got_error_from_errno("asprintf");
383 			err = parse_packed_ref_line(ref, abs_refname, line);
384 			if (!ref_is_absolute)
385 				free(abs_refname);
386 			if (err || *ref != NULL)
387 				break;
388 		}
389 		free(line);
390 		if (err)
391 			break;
392 	} while (*ref == NULL);
393 
394 	return err;
395 }
396 
397 static const struct got_error *
398 open_ref(struct got_reference **ref, const char *path_refs, const char *subdir,
399     const char *name, int lock)
400 {
401 	const struct got_error *err = NULL;
402 	char *path = NULL;
403 	char *absname = NULL;
404 	int ref_is_absolute = (strncmp(name, "refs/", 5) == 0);
405 	int ref_is_well_known = (subdir[0] == '\0' && is_well_known_ref(name));
406 
407 	*ref = NULL;
408 
409 	if (ref_is_absolute || ref_is_well_known) {
410 		if (asprintf(&path, "%s/%s", path_refs, name) == -1)
411 			return got_error_from_errno("asprintf");
412 		absname = (char *)name;
413 	} else {
414 		if (asprintf(&path, "%s/%s%s%s", path_refs, subdir,
415 		    subdir[0] ? "/" : "", name) == -1)
416 			return got_error_from_errno("asprintf");
417 
418 		if (asprintf(&absname, "refs/%s%s%s",
419 		    subdir, subdir[0] ? "/" : "", name) == -1) {
420 			err = got_error_from_errno("asprintf");
421 			goto done;
422 		}
423 	}
424 
425 	err = parse_ref_file(ref, name, absname, path, lock);
426 done:
427 	if (!ref_is_absolute && !ref_is_well_known)
428 		free(absname);
429 	free(path);
430 	return err;
431 }
432 
433 const struct got_error *
434 got_ref_open(struct got_reference **ref, struct got_repository *repo,
435    const char *refname, int lock)
436 {
437 	const struct got_error *err = NULL;
438 	char *path_refs = NULL;
439 	const char *subdirs[] = {
440 	    GOT_REF_HEADS, GOT_REF_TAGS, GOT_REF_REMOTES
441 	};
442 	size_t i;
443 	int well_known = is_well_known_ref(refname);
444 	struct got_lockfile *lf = NULL;
445 
446 	*ref = NULL;
447 
448 	path_refs = get_refs_dir_path(repo, refname);
449 	if (path_refs == NULL) {
450 		err = got_error_from_errno2("get_refs_dir_path", refname);
451 		goto done;
452 	}
453 
454 	if (well_known) {
455 		err = open_ref(ref, path_refs, "", refname, lock);
456 	} else {
457 		char *packed_refs_path;
458 		FILE *f;
459 
460 		/* Search on-disk refs before packed refs! */
461 		for (i = 0; i < nitems(subdirs); i++) {
462 			err = open_ref(ref, path_refs, subdirs[i], refname,
463 			    lock);
464 			if ((err && err->code != GOT_ERR_NOT_REF) || *ref)
465 				goto done;
466 		}
467 
468 		packed_refs_path = got_repo_get_path_packed_refs(repo);
469 		if (packed_refs_path == NULL) {
470 			err = got_error_from_errno(
471 			    "got_repo_get_path_packed_refs");
472 			goto done;
473 		}
474 
475 		if (lock) {
476 			err = got_lockfile_lock(&lf, packed_refs_path);
477 			if (err)
478 				goto done;
479 		}
480 		f = fopen(packed_refs_path, "rb");
481 		free(packed_refs_path);
482 		if (f != NULL) {
483 			err = open_packed_ref(ref, f, subdirs, nitems(subdirs),
484 			    refname);
485 			if (!err) {
486 				if (fclose(f) != 0) {
487 					err = got_error_from_errno("fclose");
488 					got_ref_close(*ref);
489 					*ref = NULL;
490 				} else if (*ref)
491 					(*ref)->lf = lf;
492 			}
493 		}
494 	}
495 done:
496 	if (!err && *ref == NULL)
497 		err = got_error_not_ref(refname);
498 	if (err && lf)
499 		got_lockfile_unlock(lf);
500 	free(path_refs);
501 	return err;
502 }
503 
504 void
505 got_ref_close(struct got_reference *ref)
506 {
507 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
508 		free(ref->ref.symref.name);
509 		free(ref->ref.symref.ref);
510 	} else
511 		free(ref->ref.ref.name);
512 	free(ref);
513 }
514 
515 struct got_reference *
516 got_ref_dup(struct got_reference *ref)
517 {
518 	struct got_reference *ret;
519 
520 	ret = calloc(1, sizeof(*ret));
521 	if (ret == NULL)
522 		return NULL;
523 
524 	ret->flags = ref->flags;
525 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
526 		ret->ref.symref.name = strdup(ref->ref.symref.name);
527 		if (ret->ref.symref.name == NULL) {
528 			free(ret);
529 			return NULL;
530 		}
531 		ret->ref.symref.ref = strdup(ref->ref.symref.ref);
532 		if (ret->ref.symref.ref == NULL) {
533 			free(ret->ref.symref.name);
534 			free(ret);
535 			return NULL;
536 		}
537 	} else {
538 		ref->ref.ref.name = strdup(ref->ref.ref.name);
539 		if (ref->ref.ref.name == NULL) {
540 			free(ret);
541 			return NULL;
542 		}
543 		memcpy(ret->ref.ref.sha1, ref->ref.ref.sha1,
544 		    sizeof(ret->ref.ref.sha1));
545 	}
546 
547 	return ret;
548 }
549 
550 const struct got_error *
551 got_reflist_entry_dup(struct got_reflist_entry **newp,
552     struct got_reflist_entry *re)
553 {
554 	const struct got_error *err = NULL;
555 	struct got_reflist_entry *new;
556 
557 	*newp = NULL;
558 
559 	new = malloc(sizeof(*new));
560 	if (new == NULL)
561 		return got_error_from_errno("malloc");
562 
563 	new->ref = got_ref_dup(re->ref);
564 	if (new->ref == NULL) {
565 		err = got_error_from_errno("got_ref_dup");
566 		free(new);
567 		return err;
568 	}
569 
570 	*newp = new;
571 	return NULL;
572 }
573 
574 static const struct got_error *
575 resolve_symbolic_ref(struct got_reference **resolved,
576     struct got_repository *repo, struct got_reference *ref)
577 {
578 	struct got_reference *nextref;
579 	const struct got_error *err;
580 
581 	err = got_ref_open(&nextref, repo, ref->ref.symref.ref, 0);
582 	if (err)
583 		return err;
584 
585 	if (nextref->flags & GOT_REF_IS_SYMBOLIC)
586 		err = resolve_symbolic_ref(resolved, repo, nextref);
587 	else
588 		*resolved = got_ref_dup(nextref);
589 
590 	got_ref_close(nextref);
591 	return err;
592 }
593 
594 static const struct got_error *
595 ref_resolve(struct got_object_id **id, struct got_repository *repo,
596     struct got_reference *ref, int recursion)
597 {
598 	const struct got_error *err;
599 
600 	if (recursion <= 0)
601 		return got_error_msg(GOT_ERR_RECURSION,
602 		    "reference recursion limit reached");
603 
604 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
605 		struct got_reference *resolved = NULL;
606 		err = resolve_symbolic_ref(&resolved, repo, ref);
607 		if (err == NULL)
608 			err = ref_resolve(id, repo, resolved, --recursion);
609 		if (resolved)
610 			got_ref_close(resolved);
611 		return err;
612 	}
613 
614 	*id = calloc(1, sizeof(**id));
615 	if (*id == NULL)
616 		return got_error_from_errno("calloc");
617 	memcpy((*id)->sha1, ref->ref.ref.sha1, sizeof((*id)->sha1));
618 	return NULL;
619 }
620 
621 const struct got_error *
622 got_ref_resolve(struct got_object_id **id, struct got_repository *repo,
623     struct got_reference *ref)
624 {
625 	return ref_resolve(id, repo, ref, GOT_REF_RECURSE_MAX);
626 }
627 
628 char *
629 got_ref_to_str(struct got_reference *ref)
630 {
631 	char *str;
632 
633 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
634 		return strdup(ref->ref.symref.ref);
635 
636 	str = malloc(SHA1_DIGEST_STRING_LENGTH);
637 	if (str == NULL)
638 		return NULL;
639 
640 	if (got_sha1_digest_to_str(ref->ref.ref.sha1, str,
641 	    SHA1_DIGEST_STRING_LENGTH) == NULL) {
642 		free(str);
643 		return NULL;
644 	}
645 
646 	return str;
647 }
648 
649 const char *
650 got_ref_get_name(struct got_reference *ref)
651 {
652 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
653 		return ref->ref.symref.name;
654 
655 	return ref->ref.ref.name;
656 }
657 
658 const char *
659 got_ref_get_symref_target(struct got_reference *ref)
660 {
661 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
662 		return ref->ref.symref.ref;
663 
664 	return NULL;
665 }
666 
667 const struct got_error *
668 got_ref_cmp_by_name(void *arg, int *cmp, struct got_reference *re1,
669     struct got_reference* re2)
670 {
671 	const char *name1 = got_ref_get_name(re1);
672 	const char *name2 = got_ref_get_name(re2);
673 
674 	*cmp = got_path_cmp(name1, name2, strlen(name1), strlen(name2));
675 	return NULL;
676 }
677 
678 const struct got_error *
679 got_ref_cmp_tags(void *arg, int *cmp, struct got_reference *ref1,
680     struct got_reference *ref2)
681 {
682 	const struct got_error *err = NULL;
683 	struct got_repository *repo = arg;
684 	struct got_object_id *id1, *id2 = NULL;
685 	struct got_tag_object *tag1 = NULL, *tag2 = NULL;
686 	struct got_commit_object *commit1 = NULL, *commit2 = NULL;
687 	time_t time1, time2;
688 
689 	*cmp = 0;
690 
691 	err = got_ref_resolve(&id1, repo, ref1);
692 	if (err)
693 		return err;
694 	err = got_object_open_as_tag(&tag1, repo, id1);
695 	if (err) {
696 		if (err->code != GOT_ERR_OBJ_TYPE)
697 			goto done;
698 		/* "lightweight" tag */
699 		err = got_object_open_as_commit(&commit1, repo, id1);
700 		if (err)
701 			goto done;
702 		time1 = got_object_commit_get_committer_time(commit1);
703 	} else
704 		time1 = got_object_tag_get_tagger_time(tag1);
705 
706 	err = got_ref_resolve(&id2, repo, ref2);
707 	if (err)
708 		goto done;
709 	err = got_object_open_as_tag(&tag2, repo, id2);
710 	if (err) {
711 		if (err->code != GOT_ERR_OBJ_TYPE)
712 			goto done;
713 		/* "lightweight" tag */
714 		err = got_object_open_as_commit(&commit2, repo, id2);
715 		if (err)
716 			goto done;
717 		time2 = got_object_commit_get_committer_time(commit2);
718 	} else
719 		time2 = got_object_tag_get_tagger_time(tag2);
720 
721 	/* Put latest tags first. */
722 	if (time1 < time2)
723 		*cmp = 1;
724 	else if (time1 > time2)
725 		*cmp = -1;
726 	else
727 		err = got_ref_cmp_by_name(NULL, cmp, ref2, ref1);
728 done:
729 	free(id1);
730 	free(id2);
731 	if (tag1)
732 		got_object_tag_close(tag1);
733 	if (tag2)
734 		got_object_tag_close(tag2);
735 	if (commit1)
736 		got_object_commit_close(commit1);
737 	if (commit2)
738 		got_object_commit_close(commit2);
739 	return err;
740 }
741 
742 static const struct got_error *
743 insert_ref(struct got_reflist_entry **newp, struct got_reflist_head *refs,
744     struct got_reference *ref, struct got_repository *repo,
745     got_ref_cmp_cb cmp_cb, void *cmp_arg)
746 {
747 	const struct got_error *err;
748 	struct got_reflist_entry *new, *re, *prev = NULL;
749 	int cmp;
750 
751 	*newp = NULL;
752 
753 	new = malloc(sizeof(*new));
754 	if (new == NULL)
755 		return got_error_from_errno("malloc");
756 	new->ref = ref;
757 	*newp = new;
758 
759 	/*
760 	 * We must de-duplicate entries on insert because packed-refs may
761 	 * contain redundant entries. On-disk refs take precedence.
762 	 * This code assumes that on-disk revs are read before packed-refs.
763 	 * We're iterating the list anyway, so insert elements sorted by name.
764 	 */
765 	re = SIMPLEQ_FIRST(refs);
766 	while (re) {
767 		err = (*cmp_cb)(cmp_arg, &cmp, re->ref, new->ref);
768 		if (err)
769 			return err;
770 		if (cmp == 0) {
771 			/* duplicate */
772 			free(new);
773 			*newp = NULL;
774 			return NULL;
775 		} else if (cmp > 0) {
776 			if (prev)
777 				SIMPLEQ_INSERT_AFTER(refs, prev, new, entry);
778 			else
779 				SIMPLEQ_INSERT_HEAD(refs, new, entry);
780 			return NULL;
781 		} else {
782 			prev = re;
783 			re = SIMPLEQ_NEXT(re, entry);
784 		}
785 	}
786 
787 	SIMPLEQ_INSERT_TAIL(refs, new, entry);
788 	return NULL;
789 }
790 
791 static const struct got_error *
792 gather_on_disk_refs(struct got_reflist_head *refs, const char *path_refs,
793     const char *subdir, struct got_repository *repo,
794     got_ref_cmp_cb cmp_cb, void *cmp_arg)
795 {
796 	const struct got_error *err = NULL;
797 	DIR *d = NULL;
798 	char *path_subdir;
799 
800 	while (subdir[0] == '/')
801 		subdir++;
802 
803 	if (asprintf(&path_subdir, "%s/%s", path_refs, subdir) == -1)
804 		return got_error_from_errno("asprintf");
805 
806 	d = opendir(path_subdir);
807 	if (d == NULL)
808 		goto done;
809 
810 	for (;;) {
811 		struct dirent *dent;
812 		struct got_reference *ref;
813 		char *child;
814 		int type;
815 
816 		dent = readdir(d);
817 		if (dent == NULL)
818 			break;
819 
820 		if (strcmp(dent->d_name, ".") == 0 ||
821 		    strcmp(dent->d_name, "..") == 0)
822 			continue;
823 
824 		err = got_path_dirent_type(&type, path_subdir, dent);
825 		if (err)
826 			break;
827 
828 		switch (type) {
829 		case DT_REG:
830 			err = open_ref(&ref, path_refs, subdir, dent->d_name,
831 			    0);
832 			if (err)
833 				goto done;
834 			if (ref) {
835 				struct got_reflist_entry *new;
836 				err = insert_ref(&new, refs, ref, repo,
837 				    cmp_cb, cmp_arg);
838 				if (err || new == NULL /* duplicate */)
839 					got_ref_close(ref);
840 				if (err)
841 					goto done;
842 			}
843 			break;
844 		case DT_DIR:
845 			if (asprintf(&child, "%s%s%s", subdir,
846 			    subdir[0] == '\0' ? "" : "/", dent->d_name) == -1) {
847 				err = got_error_from_errno("asprintf");
848 				break;
849 			}
850 			err = gather_on_disk_refs(refs, path_refs, child, repo,
851 			    cmp_cb, cmp_arg);
852 			free(child);
853 			break;
854 		default:
855 			break;
856 		}
857 	}
858 done:
859 	if (d)
860 		closedir(d);
861 	free(path_subdir);
862 	return err;
863 }
864 
865 const struct got_error *
866 got_ref_list(struct got_reflist_head *refs, struct got_repository *repo,
867     const char *ref_namespace, got_ref_cmp_cb cmp_cb, void *cmp_arg)
868 {
869 	const struct got_error *err;
870 	char *packed_refs_path, *path_refs = NULL;
871 	char *abs_namespace = NULL;
872 	char *buf = NULL, *ondisk_ref_namespace = NULL;
873 	FILE *f = NULL;
874 	struct got_reference *ref;
875 	struct got_reflist_entry *new;
876 
877 	if (ref_namespace == NULL || ref_namespace[0] == '\0') {
878 		path_refs = get_refs_dir_path(repo, GOT_REF_HEAD);
879 		if (path_refs == NULL) {
880 			err = got_error_from_errno("get_refs_dir_path");
881 			goto done;
882 		}
883 		err = open_ref(&ref, path_refs, "", GOT_REF_HEAD, 0);
884 		if (err)
885 			goto done;
886 		err = insert_ref(&new, refs, ref, repo,
887 		    cmp_cb, cmp_arg);
888 		if (err || new == NULL /* duplicate */)
889 			got_ref_close(ref);
890 		if (err && err->code != GOT_ERR_NOT_REF)
891 			goto done;
892 	} else {
893 		/* Try listing a single reference. */
894 		const char *refname = ref_namespace;
895 		path_refs = get_refs_dir_path(repo, refname);
896 		if (path_refs == NULL) {
897 			err = got_error_from_errno("get_refs_dir_path");
898 			goto done;
899 		}
900 		err = open_ref(&ref, path_refs, "", refname, 0);
901 		if (err) {
902 			if (err->code != GOT_ERR_NOT_REF)
903 				goto done;
904 			/* Try to look up references in a given namespace. */
905 		} else {
906 			err = insert_ref(&new, refs, ref, repo,
907 			    cmp_cb, cmp_arg);
908 			if (err || new == NULL /* duplicate */)
909 				got_ref_close(ref);
910 			return err;
911 		}
912 	}
913 
914 	if (ref_namespace) {
915 		size_t len;
916 		/* Canonicalize the path to eliminate double-slashes if any. */
917 		if (asprintf(&abs_namespace, "/%s", ref_namespace) == -1) {
918 			err = got_error_from_errno("asprintf");
919 			goto done;
920 		}
921 		len = strlen(abs_namespace) + 1;
922 		buf = malloc(len);
923 		if (buf == NULL) {
924 			err = got_error_from_errno("malloc");
925 			goto done;
926 		}
927 		err = got_canonpath(abs_namespace, buf, len);
928 		if (err)
929 			goto done;
930 		ondisk_ref_namespace = buf;
931 		while (ondisk_ref_namespace[0] == '/')
932 			ondisk_ref_namespace++;
933 		if (strncmp(ondisk_ref_namespace, "refs/", 5) == 0)
934 			ondisk_ref_namespace += 5;
935 		else if (strcmp(ondisk_ref_namespace, "refs") == 0)
936 			ondisk_ref_namespace = "";
937 	}
938 
939 	/* Gather on-disk refs before parsing packed-refs. */
940 	free(path_refs);
941 	path_refs = get_refs_dir_path(repo, "");
942 	if (path_refs == NULL) {
943 		err = got_error_from_errno("get_refs_dir_path");
944 		goto done;
945 	}
946 	err = gather_on_disk_refs(refs, path_refs,
947 	    ondisk_ref_namespace ? ondisk_ref_namespace : "", repo,
948 	    cmp_cb, cmp_arg);
949 	if (err)
950 		goto done;
951 
952 	/*
953 	 * The packed-refs file may contain redundant entries, in which
954 	 * case on-disk refs take precedence.
955 	 */
956 	packed_refs_path = got_repo_get_path_packed_refs(repo);
957 	if (packed_refs_path == NULL) {
958 		err = got_error_from_errno("got_repo_get_path_packed_refs");
959 		goto done;
960 	}
961 
962 	f = fopen(packed_refs_path, "r");
963 	free(packed_refs_path);
964 	if (f) {
965 		char *line;
966 		size_t len;
967 		const char delim[3] = {'\0', '\0', '\0'};
968 		for (;;) {
969 			line = fparseln(f, &len, NULL, delim, 0);
970 			if (line == NULL) {
971 				if (feof(f))
972 					break;
973 				err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
974 				goto done;
975 			}
976 			err = parse_packed_ref_line(&ref, NULL, line);
977 			free(line);
978 			if (err)
979 				goto done;
980 			if (ref) {
981 				if (ref_namespace) {
982 					const char *name;
983 					name = got_ref_get_name(ref);
984 					if (!got_path_is_child(name,
985 					    ref_namespace,
986 					    strlen(ref_namespace))) {
987 						got_ref_close(ref);
988 						continue;
989 					}
990 				}
991 				err = insert_ref(&new, refs, ref, repo,
992 				    cmp_cb, cmp_arg);
993 				if (err || new == NULL /* duplicate */)
994 					got_ref_close(ref);
995 				if (err)
996 					goto done;
997 			}
998 		}
999 	}
1000 done:
1001 	free(abs_namespace);
1002 	free(buf);
1003 	free(path_refs);
1004 	if (f && fclose(f) != 0 && err == NULL)
1005 		err = got_error_from_errno("fclose");
1006 	return err;
1007 }
1008 
1009 void
1010 got_ref_list_free(struct got_reflist_head *refs)
1011 {
1012 	struct got_reflist_entry *re;
1013 
1014 	while (!SIMPLEQ_EMPTY(refs)) {
1015 		re = SIMPLEQ_FIRST(refs);
1016 		SIMPLEQ_REMOVE_HEAD(refs, entry);
1017 		got_ref_close(re->ref);
1018 		free(re);
1019 	}
1020 
1021 }
1022 
1023 int
1024 got_ref_is_symbolic(struct got_reference *ref)
1025 {
1026 	return (ref->flags & GOT_REF_IS_SYMBOLIC);
1027 }
1028 
1029 const struct got_error *
1030 got_ref_change_ref(struct got_reference *ref, struct got_object_id *id)
1031 {
1032 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
1033 		return got_error(GOT_ERR_BAD_REF_TYPE);
1034 
1035 	memcpy(ref->ref.ref.sha1, id->sha1, sizeof(ref->ref.ref.sha1));
1036 	return NULL;
1037 }
1038 
1039 const struct got_error *
1040 got_ref_change_symref(struct got_reference *ref, const char *refname)
1041 {
1042 	char *new_name;
1043 
1044 	if ((ref->flags & GOT_REF_IS_SYMBOLIC) == 0)
1045 		return got_error(GOT_ERR_BAD_REF_TYPE);
1046 
1047 	new_name = strdup(refname);
1048 	if (new_name == NULL)
1049 		return got_error_from_errno("strdup");
1050 
1051 	free(ref->ref.symref.ref);
1052 	ref->ref.symref.ref = new_name;
1053 	return NULL;
1054 }
1055 
1056 const struct got_error *
1057 got_ref_change_symref_to_ref(struct got_reference *symref,
1058     struct got_object_id *id)
1059 {
1060 	if ((symref->flags & GOT_REF_IS_SYMBOLIC) == 0)
1061 		return got_error(GOT_ERR_BAD_REF_TYPE);
1062 
1063 	symref->ref.ref.name = symref->ref.symref.name;
1064 	memcpy(symref->ref.ref.sha1, id->sha1, SHA1_DIGEST_LENGTH);
1065 	symref->flags &= ~GOT_REF_IS_SYMBOLIC;
1066 	return NULL;
1067 }
1068 
1069 const struct got_error *
1070 got_ref_write(struct got_reference *ref, struct got_repository *repo)
1071 {
1072 	const struct got_error *err = NULL, *unlock_err = NULL;
1073 	const char *name = got_ref_get_name(ref);
1074 	char *path_refs = NULL, *path = NULL, *tmppath = NULL;
1075 	struct got_lockfile *lf = NULL;
1076 	FILE *f = NULL;
1077 	size_t n;
1078 	struct stat sb;
1079 
1080 	path_refs = get_refs_dir_path(repo, name);
1081 	if (path_refs == NULL) {
1082 		err = got_error_from_errno2("get_refs_dir_path", name);
1083 		goto done;
1084 	}
1085 
1086 	if (asprintf(&path, "%s/%s", path_refs, name) == -1) {
1087 		err = got_error_from_errno("asprintf");
1088 		goto done;
1089 	}
1090 
1091 	err = got_opentemp_named(&tmppath, &f, path);
1092 	if (err) {
1093 		char *parent;
1094 		if (!(err->code == GOT_ERR_ERRNO && errno == ENOENT))
1095 			goto done;
1096 		err = got_path_dirname(&parent, path);
1097 		if (err)
1098 			goto done;
1099 		err = got_path_mkdir(parent);
1100 		free(parent);
1101 		if (err)
1102 			goto done;
1103 		err = got_opentemp_named(&tmppath, &f, path);
1104 		if (err)
1105 			goto done;
1106 	}
1107 
1108 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
1109 		n = fprintf(f, "ref: %s\n", ref->ref.symref.ref);
1110 		if (n != strlen(ref->ref.symref.ref) + 6) {
1111 			err = got_ferror(f, GOT_ERR_IO);
1112 			goto done;
1113 		}
1114 	} else {
1115 		char hex[SHA1_DIGEST_STRING_LENGTH];
1116 		if (got_sha1_digest_to_str(ref->ref.ref.sha1, hex,
1117 		    sizeof(hex)) == NULL) {
1118 			err = got_error(GOT_ERR_BAD_REF_DATA);
1119 			goto done;
1120 		}
1121 		n = fprintf(f, "%s\n", hex);
1122 		if (n != sizeof(hex)) {
1123 			err = got_ferror(f, GOT_ERR_IO);
1124 			goto done;
1125 		}
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 (stat(path, &sb) != 0) {
1137 		if (errno != ENOENT) {
1138 			err = got_error_from_errno2("stat", path);
1139 			goto done;
1140 		}
1141 		sb.st_mode = GOT_DEFAULT_FILE_MODE;
1142 	}
1143 
1144 	if (fchmod(fileno(f), sb.st_mode) != 0) {
1145 		err = got_error_from_errno2("fchmod", tmppath);
1146 		goto done;
1147 	}
1148 
1149 	if (rename(tmppath, path) != 0) {
1150 		err = got_error_from_errno3("rename", tmppath, path);
1151 		goto done;
1152 	}
1153 	free(tmppath);
1154 	tmppath = NULL;
1155 done:
1156 	if (ref->lf == NULL && lf)
1157 		unlock_err = got_lockfile_unlock(lf);
1158 	if (f) {
1159 		if (fclose(f) != 0 && err == NULL)
1160 			err = got_error_from_errno("fclose");
1161 	}
1162 	free(path_refs);
1163 	free(path);
1164 	if (tmppath) {
1165 		if (unlink(tmppath) != 0 && err == NULL)
1166 			err = got_error_from_errno2("unlink", tmppath);
1167 		free(tmppath);
1168 	}
1169 	return err ? err : unlock_err;
1170 }
1171 
1172 static const struct got_error *
1173 delete_packed_ref(struct got_reference *delref, struct got_repository *repo)
1174 {
1175 	const struct got_error *err = NULL, *unlock_err = NULL;
1176 	struct got_lockfile *lf = NULL;
1177 	FILE *f = NULL, *tmpf = NULL;
1178 	char *packed_refs_path, *tmppath = NULL;
1179 	struct got_reflist_head refs;
1180 	int found_delref = 0;
1181 
1182 	/* The packed-refs file does not cotain symbolic references. */
1183 	if (delref->flags & GOT_REF_IS_SYMBOLIC)
1184 		return got_error(GOT_ERR_BAD_REF_DATA);
1185 
1186 	SIMPLEQ_INIT(&refs);
1187 
1188 	packed_refs_path = got_repo_get_path_packed_refs(repo);
1189 	if (packed_refs_path == NULL)
1190 		return got_error_from_errno("got_repo_get_path_packed_refs");
1191 
1192 	err = got_opentemp_named(&tmppath, &tmpf, packed_refs_path);
1193 	if (err)
1194 		goto done;
1195 
1196 	if (delref->lf == NULL) {
1197 		err = got_lockfile_lock(&lf, packed_refs_path);
1198 		if (err)
1199 			goto done;
1200 	}
1201 
1202 	f = fopen(packed_refs_path, "r");
1203 	if (f == NULL) {
1204 		err = got_error_from_errno2("fopen", packed_refs_path);
1205 		goto done;
1206 	}
1207 	for (;;) {
1208 		char *line;
1209 		size_t len;
1210 		const char delim[3] = {'\0', '\0', '\0'};
1211 		struct got_reference *ref;
1212 		struct got_reflist_entry *new;
1213 
1214 		line = fparseln(f, &len, NULL, delim, 0);
1215 		if (line == NULL) {
1216 			if (feof(f))
1217 				break;
1218 			err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
1219 			goto done;
1220 		}
1221 		err = parse_packed_ref_line(&ref, NULL, line);
1222 		free(line);
1223 		if (err)
1224 			goto done;
1225 		if (ref == NULL)
1226 			continue;
1227 
1228 		if (strcmp(ref->ref.ref.name, delref->ref.ref.name) == 0 &&
1229 		    memcmp(ref->ref.ref.sha1, delref->ref.ref.sha1,
1230 		    sizeof(delref->ref.ref.sha1)) == 0) {
1231 			found_delref = 1;
1232 			got_ref_close(ref);
1233 			continue;
1234 		}
1235 
1236 		err = insert_ref(&new, &refs, ref, repo,
1237 		    got_ref_cmp_by_name, NULL);
1238 		if (err || new == NULL /* duplicate */)
1239 			got_ref_close(ref);
1240 		if (err)
1241 			goto done;
1242 	}
1243 
1244 	if (found_delref) {
1245 		struct got_reflist_entry *re;
1246 		size_t n;
1247 		struct stat sb;
1248 
1249 		n = fprintf(tmpf, "%s\n", GOT_PACKED_REFS_HEADER);
1250 		if (n != sizeof(GOT_PACKED_REFS_HEADER)) {
1251 			err = got_ferror(f, GOT_ERR_IO);
1252 			goto done;
1253 		}
1254 
1255 		SIMPLEQ_FOREACH(re, &refs, entry) {
1256 			uint8_t hex[SHA1_DIGEST_STRING_LENGTH];
1257 
1258 			if (got_sha1_digest_to_str(re->ref->ref.ref.sha1, hex,
1259 			    sizeof(hex)) == NULL) {
1260 				err = got_error(GOT_ERR_BAD_REF_DATA);
1261 				goto done;
1262 			}
1263 			n = fprintf(tmpf, "%s ", hex);
1264 			if (n != sizeof(hex)) {
1265 				err = got_ferror(f, GOT_ERR_IO);
1266 				goto done;
1267 			}
1268 			n = fprintf(tmpf, "%s\n", re->ref->ref.ref.name);
1269 			if (n != strlen(re->ref->ref.ref.name) + 1) {
1270 				err = got_ferror(f, GOT_ERR_IO);
1271 				goto done;
1272 			}
1273 		}
1274 
1275 		if (fflush(tmpf) != 0) {
1276 			err = got_error_from_errno("fflush");
1277 			goto done;
1278 		}
1279 
1280 		if (fstat(fileno(f), &sb) != 0) {
1281 			if (errno != ENOENT) {
1282 				err = got_error_from_errno2("fstat",
1283 				    packed_refs_path);
1284 				goto done;
1285 			}
1286 			sb.st_mode = GOT_DEFAULT_FILE_MODE;
1287 		}
1288 
1289 		if (fchmod(fileno(tmpf), sb.st_mode) != 0) {
1290 			err = got_error_from_errno2("fchmod", tmppath);
1291 			goto done;
1292 		}
1293 
1294 		if (rename(tmppath, packed_refs_path) != 0) {
1295 			err = got_error_from_errno3("rename", tmppath,
1296 			    packed_refs_path);
1297 			goto done;
1298 		}
1299 	}
1300 done:
1301 	if (delref->lf == NULL && lf)
1302 		unlock_err = got_lockfile_unlock(lf);
1303 	if (f) {
1304 		if (fclose(f) != 0 && err == NULL)
1305 			err = got_error_from_errno("fclose");
1306 	}
1307 	if (tmpf) {
1308 		unlink(tmppath);
1309 		if (fclose(tmpf) != 0 && err == NULL)
1310 			err = got_error_from_errno("fclose");
1311 	}
1312 	free(tmppath);
1313 	free(packed_refs_path);
1314 	got_ref_list_free(&refs);
1315 	return err ? err : unlock_err;
1316 }
1317 
1318 static const struct got_error *
1319 delete_loose_ref(struct got_reference *ref, struct got_repository *repo)
1320 {
1321 	const struct got_error *err = NULL, *unlock_err = NULL;
1322 	const char *name = got_ref_get_name(ref);
1323 	char *path_refs = NULL, *path = NULL;
1324 	struct got_lockfile *lf = NULL;
1325 
1326 	path_refs = get_refs_dir_path(repo, name);
1327 	if (path_refs == NULL) {
1328 		err = got_error_from_errno2("get_refs_dir_path", name);
1329 		goto done;
1330 	}
1331 
1332 	if (asprintf(&path, "%s/%s", path_refs, name) == -1) {
1333 		err = got_error_from_errno("asprintf");
1334 		goto done;
1335 	}
1336 
1337 	if (ref->lf == NULL) {
1338 		err = got_lockfile_lock(&lf, path);
1339 		if (err)
1340 			goto done;
1341 	}
1342 
1343 	/* XXX: check if old content matches our expectations? */
1344 
1345 	if (unlink(path) != 0)
1346 		err = got_error_from_errno2("unlink", path);
1347 done:
1348 	if (ref->lf == NULL && lf)
1349 		unlock_err = got_lockfile_unlock(lf);
1350 
1351 	free(path_refs);
1352 	free(path);
1353 	return err ? err : unlock_err;
1354 }
1355 
1356 const struct got_error *
1357 got_ref_delete(struct got_reference *ref, struct got_repository *repo)
1358 {
1359 	const struct got_error *err = NULL;
1360 	struct got_reference *ref2;
1361 
1362 	if (ref->flags & GOT_REF_IS_PACKED) {
1363 		err = delete_packed_ref(ref, repo);
1364 		if (err)
1365 			return err;
1366 
1367 		err = got_ref_open(&ref2, repo, got_ref_get_name(ref), 0);
1368 		if (err) {
1369 			if (err->code == GOT_ERR_NOT_REF)
1370 				return NULL;
1371 			return err;
1372 		}
1373 
1374 		err = delete_loose_ref(ref2, repo);
1375 		got_ref_close(ref2);
1376 		return err;
1377 	} else {
1378 		err = delete_loose_ref(ref, repo);
1379 		if (err)
1380 			return err;
1381 
1382 		err = got_ref_open(&ref2, repo, got_ref_get_name(ref), 0);
1383 		if (err) {
1384 			if (err->code == GOT_ERR_NOT_REF)
1385 				return NULL;
1386 			return err;
1387 		}
1388 
1389 		err = delete_packed_ref(ref2, repo);
1390 		got_ref_close(ref2);
1391 		return err;
1392 	}
1393 }
1394 
1395 const struct got_error *
1396 got_ref_unlock(struct got_reference *ref)
1397 {
1398 	const struct got_error *err;
1399 	err = got_lockfile_unlock(ref->lf);
1400 	ref->lf = NULL;
1401 	return err;
1402 }