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Date:: Sun Mar 22 14:21:07 2020 UTC
Message:: allow for limiting output of 'got ref -l' to a single ref or a namespace
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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 <util.h>
30 #include <zlib.h>
31 #include <time.h>
32 #include <libgen.h>
33 
34 #include "got_error.h"
35 #include "got_object.h"
36 #include "got_repository.h"
37 #include "got_reference.h"
38 #include "got_opentemp.h"
39 #include "got_path.h"
40 
41 #include "got_lib_sha1.h"
42 #include "got_lib_delta.h"
43 #include "got_lib_inflate.h"
44 #include "got_lib_object.h"
45 #include "got_lib_lockfile.h"
46 
47 #ifndef nitems
48 #define nitems(_a) (sizeof(_a) / sizeof((_a)[0]))
49 #endif
50 
51 #define GOT_REF_HEADS	"heads"
52 #define GOT_REF_TAGS	"tags"
53 #define GOT_REF_REMOTES	"remotes"
54 
55 /*
56  * We do not resolve tags yet, and don't yet care about sorting refs either,
57  * so packed-refs files we write contain a minimal header which disables all
58  * packed-refs "traits" supported by Git.
59  */
60 #define GOT_PACKED_REFS_HEADER	"# pack-refs with:"
61 
62 /* A symbolic reference. */
63 struct got_symref {
64 	char *name;
65 	char *ref;
66 };
67 
68 #define GOT_REF_RECURSE_MAX	20
69 
70 /* A non-symbolic reference (there is no better designation). */
71 struct got_ref {
72 	char *name;
73 	u_int8_t sha1[SHA1_DIGEST_LENGTH];
74 };
75 
76 /* A reference which points to an arbitrary object. */
77 struct got_reference {
78 	unsigned int flags;
79 #define GOT_REF_IS_SYMBOLIC	0x01
80 #define GOT_REF_IS_PACKED	0x02
81 
82 	union {
83 		struct got_ref ref;
84 		struct got_symref symref;
85 	} ref;
86 
87 	struct got_lockfile *lf;
88 };
89 
90 static const struct got_error *
91 alloc_ref(struct got_reference **ref, const char *name,
92     struct got_object_id *id, int flags)
93 {
94 	const struct got_error *err = NULL;
95 
96 	*ref = calloc(1, sizeof(**ref));
97 	if (*ref == NULL)
98 		return got_error_from_errno("calloc");
99 
100 	memcpy((*ref)->ref.ref.sha1, id->sha1, sizeof((*ref)->ref.ref.sha1));
101 	(*ref)->flags = flags;
102 	(*ref)->ref.ref.name = strdup(name);
103 	if ((*ref)->ref.ref.name == NULL) {
104 		err = got_error_from_errno("strdup");
105 		got_ref_close(*ref);
106 		*ref = NULL;
107 	}
108 	return err;
109 }
110 
111 static const struct got_error *
112 alloc_symref(struct got_reference **ref, const char *name,
113     const char *target_ref, int flags)
114 {
115 	const struct got_error *err = NULL;
116 
117 	*ref = calloc(1, sizeof(**ref));
118 	if (*ref == NULL)
119 		return got_error_from_errno("calloc");
120 
121 	(*ref)->flags = GOT_REF_IS_SYMBOLIC | flags;
122 	(*ref)->ref.symref.name = strdup(name);
123 	if ((*ref)->ref.symref.name == NULL) {
124 		err = got_error_from_errno("strdup");
125 		got_ref_close(*ref);
126 		*ref = NULL;
127 		return err;
128 	}
129 	(*ref)->ref.symref.ref = strdup(target_ref);
130 	if ((*ref)->ref.symref.ref == NULL) {
131 		err = got_error_from_errno("strdup");
132 		got_ref_close(*ref);
133 		*ref = NULL;
134 	}
135 	return err;
136 }
137 
138 static const struct got_error *
139 parse_symref(struct got_reference **ref, const char *name, const char *line)
140 {
141 	if (line[0] == '\0')
142 		return got_error(GOT_ERR_BAD_REF_DATA);
143 
144 	return alloc_symref(ref, name, line, 0);
145 }
146 
147 static const struct got_error *
148 parse_ref_line(struct got_reference **ref, const char *name, const char *line)
149 {
150 	struct got_object_id id;
151 
152 	if (strncmp(line, "ref: ", 5) == 0) {
153 		line += 5;
154 		return parse_symref(ref, name, line);
155 	}
156 
157 	if (!got_parse_sha1_digest(id.sha1, line))
158 		return got_error(GOT_ERR_BAD_REF_DATA);
159 
160 	return alloc_ref(ref, name, &id, 0);
161 }
162 
163 static const struct got_error *
164 parse_ref_file(struct got_reference **ref, const char *name,
165     const char *absname, const char *abspath, int lock)
166 {
167 	const struct got_error *err = NULL;
168 	FILE *f;
169 	char *line = NULL;
170 	size_t linesize = 0;
171 	ssize_t linelen;
172 	struct got_lockfile *lf = NULL;
173 
174 	if (lock) {
175 		err = got_lockfile_lock(&lf, abspath);
176 		if (err) {
177 			if (err->code == GOT_ERR_ERRNO && errno == ENOENT)
178 				err = got_error_not_ref(name);
179 			return err;
180 		}
181 	}
182 
183 	f = fopen(abspath, "rb");
184 	if (f == NULL) {
185 		if (errno != ENOTDIR && errno != ENOENT)
186 			err = got_error_from_errno2("fopen", abspath);
187 		else
188 			err = got_error_not_ref(name);
189 		if (lock)
190 			got_lockfile_unlock(lf);
191 		return err;
192 	}
193 
194 	linelen = getline(&line, &linesize, f);
195 	if (linelen == -1) {
196 		if (feof(f))
197 			err = NULL; /* ignore empty files (could be locks) */
198 		else {
199 			if (errno == EISDIR)
200 				err = got_error(GOT_ERR_NOT_REF);
201 			else if (ferror(f))
202 				err = got_ferror(f, GOT_ERR_IO);
203 			else
204 				err = got_error_from_errno2("getline", abspath);
205 		}
206 		if (lock)
207 			got_lockfile_unlock(lf);
208 		goto done;
209 	}
210 	while (linelen > 0 && line[linelen - 1] == '\n') {
211 		line[linelen - 1] = '\0';
212 		linelen--;
213 	}
214 
215 	err = parse_ref_line(ref, absname, line);
216 	if (lock) {
217 		if (err)
218 			got_lockfile_unlock(lf);
219 		else {
220 			if (*ref)
221 				(*ref)->lf = lf;
222 			else
223 				got_lockfile_unlock(lf);
224 		}
225 	}
226 done:
227 	free(line);
228 	if (fclose(f) != 0 && err == NULL) {
229 		err = got_error_from_errno("fclose");
230 		if (*ref) {
231 			if (lock)
232 				got_ref_unlock(*ref);
233 			got_ref_close(*ref);
234 			*ref = NULL;
235 		}
236 	}
237 	return err;
238 }
239 
240 static int
241 is_well_known_ref(const char *refname)
242 {
243 	return (strcmp(refname, GOT_REF_HEAD) == 0 ||
244 	    strcmp(refname, GOT_REF_ORIG_HEAD) == 0 ||
245 	    strcmp(refname, GOT_REF_MERGE_HEAD) == 0 ||
246 	    strcmp(refname, GOT_REF_FETCH_HEAD) == 0);
247 }
248 
249 static char *
250 get_refs_dir_path(struct got_repository *repo, const char *refname)
251 {
252 	if (is_well_known_ref(refname) || strncmp(refname, "refs/", 5) == 0)
253 		return strdup(got_repo_get_path_git_dir(repo));
254 
255 	return got_repo_get_path_refs(repo);
256 }
257 
258 static int
259 is_valid_ref_name(const char *name)
260 {
261 	const char *s, *seg;
262 	const char forbidden[] = { ' ', '~', '^', ':', '?', '*', '[' , '\\' };
263 	const char *forbidden_seq[] = { "//", "..", "@{" };
264 	const char *lfs = GOT_LOCKFILE_SUFFIX;
265 	const size_t lfs_len = sizeof(GOT_LOCKFILE_SUFFIX) - 1;
266 	int i;
267 
268 	if (name[0] == '@' && name[1] == '\0')
269 		return 0;
270 
271 	s = name;
272 	seg = s;
273 	if (seg[0] == '\0' || seg[0] == '.' || seg[0] == '/')
274 		return 0;
275 	while (*s) {
276 		for (i = 0; i < nitems(forbidden); i++) {
277 			if (*s == forbidden[i])
278 				return 0;
279 		}
280 		for (i = 0; i < nitems(forbidden_seq); i++) {
281 			if (s[0] == forbidden_seq[i][0] &&
282 			    s[1] == forbidden_seq[i][1])
283 				return 0;
284 		}
285 		if (iscntrl((unsigned char)s[0]))
286 			return 0;
287 		if (s[0] == '.' && s[1] == '\0')
288 			return 0;
289 		if (*s == '/') {
290 			const char *nextseg = s + 1;
291 			if (nextseg[0] == '\0' || nextseg[0] == '.' ||
292 			    nextseg[0] == '/')
293 				return 0;
294 			if (seg <= s - lfs_len &&
295 			    strncmp(s - lfs_len, lfs, lfs_len) == 0)
296 				return 0;
297 			seg = nextseg;
298 		}
299 		s++;
300 	}
301 
302 	if (seg <= s - lfs_len &&
303 	    strncmp(s - lfs_len, lfs, lfs_len) == 0)
304 		return 0;
305 
306 	return 1;
307 }
308 
309 const struct got_error *
310 got_ref_alloc(struct got_reference **ref, const char *name,
311     struct got_object_id *id)
312 {
313 	if (!is_valid_ref_name(name))
314 		return got_error_path(name, GOT_ERR_BAD_REF_NAME);
315 
316 	return alloc_ref(ref, name, id, 0);
317 }
318 
319 const struct got_error *
320 got_ref_alloc_symref(struct got_reference **ref, const char *name,
321 	struct got_reference *target_ref)
322 {
323 	if (!is_valid_ref_name(name))
324 		return got_error_path(name, GOT_ERR_BAD_REF_NAME);
325 
326 	return alloc_symref(ref, name, got_ref_get_name(target_ref), 0);
327 }
328 
329 static const struct got_error *
330 parse_packed_ref_line(struct got_reference **ref, const char *abs_refname,
331     const char *line)
332 {
333 	struct got_object_id id;
334 	const char *name;
335 
336 	*ref = NULL;
337 
338 	if (line[0] == '#' || line[0] == '^')
339 		return NULL;
340 
341 	if (!got_parse_sha1_digest(id.sha1, line))
342 		return got_error(GOT_ERR_BAD_REF_DATA);
343 
344 	if (abs_refname) {
345 		if (strcmp(line + SHA1_DIGEST_STRING_LENGTH, abs_refname) != 0)
346 			return NULL;
347 		name = abs_refname;
348 	} else
349 		name = line + SHA1_DIGEST_STRING_LENGTH;
350 
351 	return alloc_ref(ref, name, &id, GOT_REF_IS_PACKED);
352 }
353 
354 static const struct got_error *
355 open_packed_ref(struct got_reference **ref, FILE *f, const char **subdirs,
356     int nsubdirs, const char *refname)
357 {
358 	const struct got_error *err = NULL;
359 	char *abs_refname;
360 	char *line;
361 	size_t len;
362 	const char delim[3] = {'\0', '\0', '\0'};
363 	int i, ref_is_absolute = (strncmp(refname, "refs/", 5) == 0);
364 
365 	*ref = NULL;
366 
367 	if (ref_is_absolute)
368 		abs_refname = (char *)refname;
369 	do {
370 		line = fparseln(f, &len, NULL, delim, 0);
371 		if (line == NULL) {
372 			if (feof(f))
373 				break;
374 			err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
375 			break;
376 		}
377 		for (i = 0; i < nsubdirs; i++) {
378 			if (!ref_is_absolute &&
379 			    asprintf(&abs_refname, "refs/%s/%s", subdirs[i],
380 			    refname) == -1)
381 				return got_error_from_errno("asprintf");
382 			err = parse_packed_ref_line(ref, abs_refname, line);
383 			if (!ref_is_absolute)
384 				free(abs_refname);
385 			if (err || *ref != NULL)
386 				break;
387 		}
388 		free(line);
389 		if (err)
390 			break;
391 	} while (*ref == NULL);
392 
393 	return err;
394 }
395 
396 static const struct got_error *
397 open_ref(struct got_reference **ref, const char *path_refs, const char *subdir,
398     const char *name, int lock)
399 {
400 	const struct got_error *err = NULL;
401 	char *path = NULL;
402 	char *absname = NULL;
403 	int ref_is_absolute = (strncmp(name, "refs/", 5) == 0);
404 	int ref_is_well_known = is_well_known_ref(name);
405 
406 	*ref = NULL;
407 
408 	if (ref_is_absolute || ref_is_well_known) {
409 		if (asprintf(&path, "%s/%s", path_refs, name) == -1)
410 			return got_error_from_errno("asprintf");
411 		absname = (char *)name;
412 	} else {
413 		if (asprintf(&path, "%s/%s%s%s", path_refs, subdir,
414 		    subdir[0] ? "/" : "", name) == -1)
415 			return got_error_from_errno("asprintf");
416 
417 		if (asprintf(&absname, "refs/%s%s%s",
418 		    subdir, subdir[0] ? "/" : "", name) == -1) {
419 			err = got_error_from_errno("asprintf");
420 			goto done;
421 		}
422 	}
423 
424 	err = parse_ref_file(ref, name, absname, path, lock);
425 done:
426 	if (!ref_is_absolute && !ref_is_well_known)
427 		free(absname);
428 	free(path);
429 	return err;
430 }
431 
432 const struct got_error *
433 got_ref_open(struct got_reference **ref, struct got_repository *repo,
434    const char *refname, int lock)
435 {
436 	const struct got_error *err = NULL;
437 	char *path_refs = NULL;
438 	const char *subdirs[] = {
439 	    GOT_REF_HEADS, GOT_REF_TAGS, GOT_REF_REMOTES
440 	};
441 	int i, well_known = is_well_known_ref(refname);
442 	struct got_lockfile *lf = NULL;
443 
444 	*ref = NULL;
445 
446 	path_refs = get_refs_dir_path(repo, refname);
447 	if (path_refs == NULL) {
448 		err = got_error_from_errno2("get_refs_dir_path", refname);
449 		goto done;
450 	}
451 
452 	if (well_known) {
453 		err = open_ref(ref, path_refs, "", refname, lock);
454 	} else {
455 		char *packed_refs_path;
456 		FILE *f;
457 
458 		/* Search on-disk refs before packed refs! */
459 		for (i = 0; i < nitems(subdirs); i++) {
460 			err = open_ref(ref, path_refs, subdirs[i], refname,
461 			    lock);
462 			if ((err && err->code != GOT_ERR_NOT_REF) || *ref)
463 				goto done;
464 		}
465 
466 		packed_refs_path = got_repo_get_path_packed_refs(repo);
467 		if (packed_refs_path == NULL) {
468 			err = got_error_from_errno(
469 			    "got_repo_get_path_packed_refs");
470 			goto done;
471 		}
472 
473 		if (lock) {
474 			err = got_lockfile_lock(&lf, packed_refs_path);
475 			if (err)
476 				goto done;
477 		}
478 		f = fopen(packed_refs_path, "rb");
479 		free(packed_refs_path);
480 		if (f != NULL) {
481 			err = open_packed_ref(ref, f, subdirs, nitems(subdirs),
482 			    refname);
483 			if (!err) {
484 				if (fclose(f) != 0) {
485 					err = got_error_from_errno("fclose");
486 					got_ref_close(*ref);
487 					*ref = NULL;
488 				} else if (*ref)
489 					(*ref)->lf = lf;
490 			}
491 		}
492 	}
493 done:
494 	if (!err && *ref == NULL)
495 		err = got_error_not_ref(refname);
496 	if (err && lf)
497 		got_lockfile_unlock(lf);
498 	free(path_refs);
499 	return err;
500 }
501 
502 void
503 got_ref_close(struct got_reference *ref)
504 {
505 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
506 		free(ref->ref.symref.name);
507 		free(ref->ref.symref.ref);
508 	} else
509 		free(ref->ref.ref.name);
510 	free(ref);
511 }
512 
513 struct got_reference *
514 got_ref_dup(struct got_reference *ref)
515 {
516 	struct got_reference *ret;
517 
518 	ret = calloc(1, sizeof(*ret));
519 	if (ret == NULL)
520 		return NULL;
521 
522 	ret->flags = ref->flags;
523 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
524 		ret->ref.symref.name = strdup(ref->ref.symref.name);
525 		if (ret->ref.symref.name == NULL) {
526 			free(ret);
527 			return NULL;
528 		}
529 		ret->ref.symref.ref = strdup(ref->ref.symref.ref);
530 		if (ret->ref.symref.ref == NULL) {
531 			free(ret->ref.symref.name);
532 			free(ret);
533 			return NULL;
534 		}
535 	} else {
536 		ref->ref.ref.name = strdup(ref->ref.ref.name);
537 		if (ref->ref.ref.name == NULL) {
538 			free(ret);
539 			return NULL;
540 		}
541 		memcpy(ret->ref.ref.sha1, ref->ref.ref.sha1,
542 		    sizeof(ret->ref.ref.sha1));
543 	}
544 
545 	return ret;
546 }
547 
548 const struct got_error *
549 got_reflist_entry_dup(struct got_reflist_entry **newp,
550     struct got_reflist_entry *re)
551 {
552 	const struct got_error *err = NULL;
553 	struct got_reflist_entry *new;
554 
555 	*newp = NULL;
556 
557 	new = malloc(sizeof(*new));
558 	if (new == NULL)
559 		return got_error_from_errno("malloc");
560 
561 	new->ref = got_ref_dup(re->ref);
562 	if (new->ref == NULL) {
563 		err = got_error_from_errno("got_ref_dup");
564 		free(new);
565 		return err;
566 	}
567 
568 	new->id = got_object_id_dup(re->id);
569 	if (new->id == NULL) {
570 		err = got_error_from_errno("got_ref_dup");
571 		free(new->id);
572 		free(new);
573 		return err;
574 	}
575 
576 	*newp = new;
577 	return NULL;
578 }
579 
580 static const struct got_error *
581 resolve_symbolic_ref(struct got_reference **resolved,
582     struct got_repository *repo, struct got_reference *ref)
583 {
584 	struct got_reference *nextref;
585 	const struct got_error *err;
586 
587 	err = got_ref_open(&nextref, repo, ref->ref.symref.ref, 0);
588 	if (err)
589 		return err;
590 
591 	if (nextref->flags & GOT_REF_IS_SYMBOLIC)
592 		err = resolve_symbolic_ref(resolved, repo, nextref);
593 	else
594 		*resolved = got_ref_dup(nextref);
595 
596 	got_ref_close(nextref);
597 	return err;
598 }
599 
600 static const struct got_error *
601 ref_resolve(struct got_object_id **id, struct got_repository *repo,
602     struct got_reference *ref, int recursion)
603 {
604 	const struct got_error *err;
605 
606 	if (recursion <= 0)
607 		return got_error_msg(GOT_ERR_RECURSION,
608 		    "reference recursion limit reached");
609 
610 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
611 		struct got_reference *resolved = NULL;
612 		err = resolve_symbolic_ref(&resolved, repo, ref);
613 		if (err == NULL)
614 			err = ref_resolve(id, repo, resolved, --recursion);
615 		if (resolved)
616 			got_ref_close(resolved);
617 		return err;
618 	}
619 
620 	*id = calloc(1, sizeof(**id));
621 	if (*id == NULL)
622 		return got_error_from_errno("calloc");
623 	memcpy((*id)->sha1, ref->ref.ref.sha1, sizeof((*id)->sha1));
624 	return NULL;
625 }
626 
627 const struct got_error *
628 got_ref_resolve(struct got_object_id **id, struct got_repository *repo,
629     struct got_reference *ref)
630 {
631 	return ref_resolve(id, repo, ref, GOT_REF_RECURSE_MAX);
632 }
633 
634 char *
635 got_ref_to_str(struct got_reference *ref)
636 {
637 	char *str;
638 
639 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
640 		return strdup(ref->ref.symref.ref);
641 
642 	str = malloc(SHA1_DIGEST_STRING_LENGTH);
643 	if (str == NULL)
644 		return NULL;
645 
646 	if (got_sha1_digest_to_str(ref->ref.ref.sha1, str,
647 	    SHA1_DIGEST_STRING_LENGTH) == NULL) {
648 		free(str);
649 		return NULL;
650 	}
651 
652 	return str;
653 }
654 
655 const char *
656 got_ref_get_name(struct got_reference *ref)
657 {
658 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
659 		return ref->ref.symref.name;
660 
661 	return ref->ref.ref.name;
662 }
663 
664 const char *
665 got_ref_get_symref_target(struct got_reference *ref)
666 {
667 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
668 		return ref->ref.symref.ref;
669 
670 	return NULL;
671 }
672 
673 const struct got_error *
674 got_ref_cmp_by_name(void *arg, int *cmp, struct got_reference *re1,
675     struct got_reference* re2)
676 {
677 	const char *name1 = got_ref_get_name(re1);
678 	const char *name2 = got_ref_get_name(re2);
679 
680 	*cmp = got_path_cmp(name1, name2, strlen(name1), strlen(name2));
681 	return NULL;
682 }
683 
684 const struct got_error *
685 got_ref_cmp_tags(void *arg, int *cmp, struct got_reference *ref1,
686     struct got_reference *ref2)
687 {
688 	const struct got_error *err = NULL;
689 	struct got_repository *repo = arg;
690 	struct got_object_id *id1, *id2 = NULL;
691 	struct got_tag_object *tag1 = NULL, *tag2 = NULL;
692 	struct got_commit_object *commit1 = NULL, *commit2 = NULL;
693 	time_t time1, time2;
694 
695 	*cmp = 0;
696 
697 	err = got_ref_resolve(&id1, repo, ref1);
698 	if (err)
699 		return err;
700 	err = got_object_open_as_tag(&tag1, repo, id1);
701 	if (err) {
702 		if (err->code != GOT_ERR_OBJ_TYPE)
703 			goto done;
704 		/* "lightweight" tag */
705 		err = got_object_open_as_commit(&commit1, repo, id1);
706 		if (err)
707 			goto done;
708 		time1 = got_object_commit_get_committer_time(commit1);
709 	} else
710 		time1 = got_object_tag_get_tagger_time(tag1);
711 
712 	err = got_ref_resolve(&id2, repo, ref2);
713 	if (err)
714 		goto done;
715 	err = got_object_open_as_tag(&tag2, repo, id2);
716 	if (err) {
717 		if (err->code != GOT_ERR_OBJ_TYPE)
718 			goto done;
719 		/* "lightweight" tag */
720 		err = got_object_open_as_commit(&commit2, repo, id2);
721 		if (err)
722 			goto done;
723 		time2 = got_object_commit_get_committer_time(commit2);
724 	} else
725 		time2 = got_object_tag_get_tagger_time(tag2);
726 
727 	/* Put latest tags first. */
728 	if (time1 < time2)
729 		*cmp = 1;
730 	else if (time1 > time2)
731 		*cmp = -1;
732 	else
733 		err = got_ref_cmp_by_name(NULL, cmp, ref2, ref1);
734 done:
735 	free(id1);
736 	free(id2);
737 	if (tag1)
738 		got_object_tag_close(tag1);
739 	if (tag2)
740 		got_object_tag_close(tag2);
741 	if (commit1)
742 		got_object_commit_close(commit1);
743 	if (commit2)
744 		got_object_commit_close(commit2);
745 	return err;
746 }
747 
748 static const struct got_error *
749 insert_ref(struct got_reflist_entry **newp, struct got_reflist_head *refs,
750     struct got_reference *ref, struct got_repository *repo,
751     got_ref_cmp_cb cmp_cb, void *cmp_arg)
752 {
753 	const struct got_error *err;
754 	struct got_object_id *id;
755 	struct got_reflist_entry *new, *re, *prev = NULL;
756 	int cmp;
757 
758 	*newp = NULL;
759 
760 	err = got_ref_resolve(&id, repo, ref);
761 	if (err)
762 		return err;
763 
764 	new = malloc(sizeof(*new));
765 	if (new == NULL) {
766 		free(id);
767 		return got_error_from_errno("malloc");
768 	}
769 	new->ref = ref;
770 	new->id = id;
771 	*newp = new;
772 
773 	/*
774 	 * We must de-duplicate entries on insert because packed-refs may
775 	 * contain redundant entries. On-disk refs take precedence.
776 	 * This code assumes that on-disk revs are read before packed-refs.
777 	 * We're iterating the list anyway, so insert elements sorted by name.
778 	 */
779 	re = SIMPLEQ_FIRST(refs);
780 	while (re) {
781 		err = (*cmp_cb)(cmp_arg, &cmp, re->ref, new->ref);
782 		if (err)
783 			return err;
784 		if (cmp == 0) {
785 			/* duplicate */
786 			free(new->id);
787 			free(new);
788 			*newp = NULL;
789 			return NULL;
790 		} else if (cmp > 0) {
791 			if (prev)
792 				SIMPLEQ_INSERT_AFTER(refs, prev, new, entry);
793 			else
794 				SIMPLEQ_INSERT_HEAD(refs, new, entry);
795 			return NULL;
796 		} else {
797 			prev = re;
798 			re = SIMPLEQ_NEXT(re, entry);
799 		}
800 	}
801 
802 	SIMPLEQ_INSERT_TAIL(refs, new, entry);
803 	return NULL;
804 }
805 
806 static const struct got_error *
807 gather_on_disk_refs(struct got_reflist_head *refs, const char *path_refs,
808     const char *subdir, struct got_repository *repo,
809     got_ref_cmp_cb cmp_cb, void *cmp_arg)
810 {
811 	const struct got_error *err = NULL;
812 	DIR *d = NULL;
813 	char *path_subdir;
814 
815 	while (subdir[0] == '/')
816 		subdir++;
817 
818 	if (asprintf(&path_subdir, "%s/%s", path_refs, subdir) == -1)
819 		return got_error_from_errno("asprintf");
820 
821 	d = opendir(path_subdir);
822 	if (d == NULL)
823 		goto done;
824 
825 	for (;;) {
826 		struct dirent *dent;
827 		struct got_reference *ref;
828 		char *child;
829 
830 		dent = readdir(d);
831 		if (dent == NULL)
832 			break;
833 
834 		if (strcmp(dent->d_name, ".") == 0 ||
835 		    strcmp(dent->d_name, "..") == 0)
836 			continue;
837 
838 		switch (dent->d_type) {
839 		case DT_REG:
840 			err = open_ref(&ref, path_refs, subdir, dent->d_name,
841 			    0);
842 			if (err)
843 				goto done;
844 			if (ref) {
845 				struct got_reflist_entry *new;
846 				err = insert_ref(&new, refs, ref, repo,
847 				    cmp_cb, cmp_arg);
848 				if (err || new == NULL /* duplicate */)
849 					got_ref_close(ref);
850 				if (err)
851 					goto done;
852 			}
853 			break;
854 		case DT_DIR:
855 			if (asprintf(&child, "%s%s%s", subdir,
856 			    subdir[0] == '\0' ? "" : "/", dent->d_name) == -1) {
857 				err = got_error_from_errno("asprintf");
858 				break;
859 			}
860 			err = gather_on_disk_refs(refs, path_refs, child, repo,
861 			    cmp_cb, cmp_arg);
862 			free(child);
863 			break;
864 		default:
865 			break;
866 		}
867 	}
868 done:
869 	if (d)
870 		closedir(d);
871 	free(path_subdir);
872 	return err;
873 }
874 
875 const struct got_error *
876 got_ref_list(struct got_reflist_head *refs, struct got_repository *repo,
877     const char *ref_namespace, got_ref_cmp_cb cmp_cb, void *cmp_arg)
878 {
879 	const struct got_error *err;
880 	char *packed_refs_path, *path_refs = NULL;
881 	char *abs_namespace = NULL;
882 	char *buf = NULL, *ondisk_ref_namespace = NULL;
883 	FILE *f = NULL;
884 	struct got_reference *ref;
885 	struct got_reflist_entry *new;
886 
887 	if (ref_namespace == NULL || ref_namespace[0] == '\0') {
888 		path_refs = get_refs_dir_path(repo, GOT_REF_HEAD);
889 		if (path_refs == NULL) {
890 			err = got_error_from_errno("get_refs_dir_path");
891 			goto done;
892 		}
893 		err = open_ref(&ref, path_refs, "", GOT_REF_HEAD, 0);
894 		if (err)
895 			goto done;
896 		err = insert_ref(&new, refs, ref, repo,
897 		    cmp_cb, cmp_arg);
898 		if (err || new == NULL /* duplicate */)
899 			got_ref_close(ref);
900 		if (err && err->code != GOT_ERR_NOT_REF)
901 			goto done;
902 	} else {
903 		/* Try listing a single reference. */
904 		const char *refname = ref_namespace;
905 		path_refs = get_refs_dir_path(repo, refname);
906 		if (path_refs == NULL) {
907 			err = got_error_from_errno("get_refs_dir_path");
908 			goto done;
909 		}
910 		err = open_ref(&ref, path_refs, "", refname, 0);
911 		if (err) {
912 			if (err->code != GOT_ERR_NOT_REF)
913 				goto done;
914 			/* Try to look up references in a given namespace. */
915 		} else {
916 			err = insert_ref(&new, refs, ref, repo,
917 			    cmp_cb, cmp_arg);
918 			if (err || new == NULL /* duplicate */)
919 				got_ref_close(ref);
920 			return err;
921 		}
922 	}
923 
924 	if (ref_namespace) {
925 		size_t len;
926 		/* Canonicalize the path to eliminate double-slashes if any. */
927 		if (asprintf(&abs_namespace, "/%s", ref_namespace) == -1) {
928 			err = got_error_from_errno("asprintf");
929 			goto done;
930 		}
931 		len = strlen(abs_namespace) + 1;
932 		buf = malloc(len);
933 		if (buf == NULL) {
934 			err = got_error_from_errno("malloc");
935 			goto done;
936 		}
937 		err = got_canonpath(abs_namespace, buf, len);
938 		if (err)
939 			goto done;
940 		ondisk_ref_namespace = buf;
941 		while (ondisk_ref_namespace[0] == '/')
942 			ondisk_ref_namespace++;
943 		if (strncmp(ondisk_ref_namespace, "refs/", 5) == 0)
944 			ondisk_ref_namespace += 5;
945 		else if (strcmp(ondisk_ref_namespace, "refs") == 0)
946 			ondisk_ref_namespace = "";
947 	}
948 
949 	/* Gather on-disk refs before parsing packed-refs. */
950 	free(path_refs);
951 	path_refs = get_refs_dir_path(repo, "");
952 	if (path_refs == NULL) {
953 		err = got_error_from_errno("get_refs_dir_path");
954 		goto done;
955 	}
956 	err = gather_on_disk_refs(refs, path_refs,
957 	    ondisk_ref_namespace ? ondisk_ref_namespace : "", repo,
958 	    cmp_cb, cmp_arg);
959 	if (err)
960 		goto done;
961 
962 	/*
963 	 * The packed-refs file may contain redundant entries, in which
964 	 * case on-disk refs take precedence.
965 	 */
966 	packed_refs_path = got_repo_get_path_packed_refs(repo);
967 	if (packed_refs_path == NULL) {
968 		err = got_error_from_errno("got_repo_get_path_packed_refs");
969 		goto done;
970 	}
971 
972 	f = fopen(packed_refs_path, "r");
973 	free(packed_refs_path);
974 	if (f) {
975 		char *line;
976 		size_t len;
977 		const char delim[3] = {'\0', '\0', '\0'};
978 		for (;;) {
979 			line = fparseln(f, &len, NULL, delim, 0);
980 			if (line == NULL) {
981 				if (feof(f))
982 					break;
983 				err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
984 				goto done;
985 			}
986 			err = parse_packed_ref_line(&ref, NULL, line);
987 			free(line);
988 			if (err)
989 				goto done;
990 			if (ref) {
991 				if (ref_namespace) {
992 					const char *name;
993 					name = got_ref_get_name(ref);
994 					if (!got_path_is_child(name,
995 					    ref_namespace,
996 					    strlen(ref_namespace))) {
997 						got_ref_close(ref);
998 						continue;
999 					}
1000 				}
1001 				err = insert_ref(&new, refs, ref, repo,
1002 				    cmp_cb, cmp_arg);
1003 				if (err || new == NULL /* duplicate */)
1004 					got_ref_close(ref);
1005 				if (err)
1006 					goto done;
1007 			}
1008 		}
1009 	}
1010 done:
1011 	free(abs_namespace);
1012 	free(buf);
1013 	free(path_refs);
1014 	if (f && fclose(f) != 0 && err == NULL)
1015 		err = got_error_from_errno("fclose");
1016 	return err;
1017 }
1018 
1019 void
1020 got_ref_list_free(struct got_reflist_head *refs)
1021 {
1022 	struct got_reflist_entry *re;
1023 
1024 	while (!SIMPLEQ_EMPTY(refs)) {
1025 		re = SIMPLEQ_FIRST(refs);
1026 		SIMPLEQ_REMOVE_HEAD(refs, entry);
1027 		got_ref_close(re->ref);
1028 		free(re->id);
1029 		free(re);
1030 	}
1031 
1032 }
1033 
1034 int
1035 got_ref_is_symbolic(struct got_reference *ref)
1036 {
1037 	return (ref->flags & GOT_REF_IS_SYMBOLIC);
1038 }
1039 
1040 const struct got_error *
1041 got_ref_change_ref(struct got_reference *ref, struct got_object_id *id)
1042 {
1043 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
1044 		return got_error(GOT_ERR_BAD_REF_TYPE);
1045 
1046 	memcpy(ref->ref.ref.sha1, id->sha1, sizeof(ref->ref.ref.sha1));
1047 	return NULL;
1048 }
1049 
1050 const struct got_error *
1051 got_ref_change_symref(struct got_reference *ref, char *refname)
1052 {
1053 	char *new_name;
1054 
1055 	if ((ref->flags & GOT_REF_IS_SYMBOLIC) == 0)
1056 		return got_error(GOT_ERR_BAD_REF_TYPE);
1057 
1058 	new_name = strdup(refname);
1059 	if (new_name == NULL)
1060 		return got_error_from_errno("strdup");
1061 
1062 	free(ref->ref.symref.name);
1063 	ref->ref.symref.name = new_name;
1064 	return NULL;
1065 }
1066 
1067 const struct got_error *
1068 got_ref_change_symref_to_ref(struct got_reference *symref,
1069     struct got_object_id *id)
1070 {
1071 	if ((symref->flags & GOT_REF_IS_SYMBOLIC) == 0)
1072 		return got_error(GOT_ERR_BAD_REF_TYPE);
1073 
1074 	symref->ref.ref.name = symref->ref.symref.name;
1075 	memcpy(symref->ref.ref.sha1, id->sha1, SHA1_DIGEST_LENGTH);
1076 	symref->flags &= ~GOT_REF_IS_SYMBOLIC;
1077 	return NULL;
1078 }
1079 
1080 const struct got_error *
1081 got_ref_write(struct got_reference *ref, struct got_repository *repo)
1082 {
1083 	const struct got_error *err = NULL, *unlock_err = NULL;
1084 	const char *name = got_ref_get_name(ref);
1085 	char *path_refs = NULL, *path = NULL, *tmppath = NULL;
1086 	struct got_lockfile *lf = NULL;
1087 	FILE *f = NULL;
1088 	size_t n;
1089 	struct stat sb;
1090 
1091 	path_refs = get_refs_dir_path(repo, name);
1092 	if (path_refs == NULL) {
1093 		err = got_error_from_errno2("get_refs_dir_path", name);
1094 		goto done;
1095 	}
1096 
1097 	if (asprintf(&path, "%s/%s", path_refs, name) == -1) {
1098 		err = got_error_from_errno("asprintf");
1099 		goto done;
1100 	}
1101 
1102 	err = got_opentemp_named(&tmppath, &f, path);
1103 	if (err) {
1104 		char *parent;
1105 		if (!(err->code == GOT_ERR_ERRNO && errno == ENOENT))
1106 			goto done;
1107 		err = got_path_dirname(&parent, path);
1108 		if (err)
1109 			goto done;
1110 		err = got_path_mkdir(parent);
1111 		free(parent);
1112 		if (err)
1113 			goto done;
1114 		err = got_opentemp_named(&tmppath, &f, path);
1115 		if (err)
1116 			goto done;
1117 	}
1118 
1119 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
1120 		n = fprintf(f, "ref: %s\n", ref->ref.symref.ref);
1121 		if (n != strlen(ref->ref.symref.ref) + 6) {
1122 			err = got_ferror(f, GOT_ERR_IO);
1123 			goto done;
1124 		}
1125 	} else {
1126 		char hex[SHA1_DIGEST_STRING_LENGTH];
1127 		if (got_sha1_digest_to_str(ref->ref.ref.sha1, hex,
1128 		    sizeof(hex)) == NULL) {
1129 			err = got_error(GOT_ERR_BAD_REF_DATA);
1130 			goto done;
1131 		}
1132 		n = fprintf(f, "%s\n", hex);
1133 		if (n != sizeof(hex)) {
1134 			err = got_ferror(f, GOT_ERR_IO);
1135 			goto done;
1136 		}
1137 	}
1138 
1139 	if (ref->lf == NULL) {
1140 		err = got_lockfile_lock(&lf, path);
1141 		if (err)
1142 			goto done;
1143 	}
1144 
1145 	/* XXX: check if old content matches our expectations? */
1146 
1147 	if (stat(path, &sb) != 0) {
1148 		if (errno != ENOENT) {
1149 			err = got_error_from_errno2("stat", path);
1150 			goto done;
1151 		}
1152 		sb.st_mode = GOT_DEFAULT_FILE_MODE;
1153 	}
1154 
1155 	if (rename(tmppath, path) != 0) {
1156 		err = got_error_from_errno3("rename", tmppath, path);
1157 		goto done;
1158 	}
1159 	free(tmppath);
1160 	tmppath = NULL;
1161 
1162 	if (chmod(path, sb.st_mode) != 0) {
1163 		err = got_error_from_errno2("chmod", path);
1164 		goto done;
1165 	}
1166 done:
1167 	if (ref->lf == NULL && lf)
1168 		unlock_err = got_lockfile_unlock(lf);
1169 	if (f) {
1170 		if (fclose(f) != 0 && err == NULL)
1171 			err = got_error_from_errno("fclose");
1172 	}
1173 	free(path_refs);
1174 	free(path);
1175 	if (tmppath) {
1176 		if (unlink(tmppath) != 0 && err == NULL)
1177 			err = got_error_from_errno2("unlink", tmppath);
1178 		free(tmppath);
1179 	}
1180 	return err ? err : unlock_err;
1181 }
1182 
1183 static const struct got_error *
1184 delete_packed_ref(struct got_reference *delref, struct got_repository *repo)
1185 {
1186 	const struct got_error *err = NULL, *unlock_err = NULL;
1187 	struct got_lockfile *lf = NULL;
1188 	FILE *f = NULL, *tmpf = NULL;
1189 	char *packed_refs_path, *tmppath = NULL;
1190 	struct got_reflist_head refs;
1191 	int found_delref = 0;
1192 
1193 	/* The packed-refs file does not cotain symbolic references. */
1194 	if (delref->flags & GOT_REF_IS_SYMBOLIC)
1195 		return got_error(GOT_ERR_BAD_REF_DATA);
1196 
1197 	SIMPLEQ_INIT(&refs);
1198 
1199 	packed_refs_path = got_repo_get_path_packed_refs(repo);
1200 	if (packed_refs_path == NULL)
1201 		return got_error_from_errno("got_repo_get_path_packed_refs");
1202 
1203 	err = got_opentemp_named(&tmppath, &tmpf, packed_refs_path);
1204 	if (err)
1205 		goto done;
1206 
1207 	if (delref->lf == NULL) {
1208 		err = got_lockfile_lock(&lf, packed_refs_path);
1209 		if (err)
1210 			goto done;
1211 	}
1212 
1213 	f = fopen(packed_refs_path, "r");
1214 	if (f == NULL) {
1215 		err = got_error_from_errno2("fopen", packed_refs_path);
1216 		goto done;
1217 	}
1218 	for (;;) {
1219 		char *line;
1220 		size_t len;
1221 		const char delim[3] = {'\0', '\0', '\0'};
1222 		struct got_reference *ref;
1223 		struct got_reflist_entry *new;
1224 
1225 		line = fparseln(f, &len, NULL, delim, 0);
1226 		if (line == NULL) {
1227 			if (feof(f))
1228 				break;
1229 			err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
1230 			goto done;
1231 		}
1232 		err = parse_packed_ref_line(&ref, NULL, line);
1233 		free(line);
1234 		if (err)
1235 			goto done;
1236 		if (ref == NULL)
1237 			continue;
1238 
1239 		if (strcmp(ref->ref.ref.name, delref->ref.ref.name) == 0 &&
1240 		    memcmp(ref->ref.ref.sha1, delref->ref.ref.sha1,
1241 		    sizeof(delref->ref.ref.sha1)) == 0) {
1242 			found_delref = 1;
1243 			got_ref_close(ref);
1244 			continue;
1245 		}
1246 
1247 		err = insert_ref(&new, &refs, ref, repo,
1248 		    got_ref_cmp_by_name, NULL);
1249 		if (err || new == NULL /* duplicate */)
1250 			got_ref_close(ref);
1251 		if (err)
1252 			goto done;
1253 	}
1254 
1255 	if (found_delref) {
1256 		struct got_reflist_entry *re;
1257 		size_t n;
1258 		struct stat sb;
1259 
1260 		n = fprintf(tmpf, "%s\n", GOT_PACKED_REFS_HEADER);
1261 		if (n != sizeof(GOT_PACKED_REFS_HEADER)) {
1262 			err = got_ferror(f, GOT_ERR_IO);
1263 			goto done;
1264 		}
1265 
1266 		SIMPLEQ_FOREACH(re, &refs, entry) {
1267 			uint8_t hex[SHA1_DIGEST_STRING_LENGTH];
1268 
1269 			if (got_sha1_digest_to_str(re->ref->ref.ref.sha1, hex,
1270 			    sizeof(hex)) == NULL) {
1271 				err = got_error(GOT_ERR_BAD_REF_DATA);
1272 				goto done;
1273 			}
1274 			n = fprintf(tmpf, "%s ", hex);
1275 			if (n != sizeof(hex)) {
1276 				err = got_ferror(f, GOT_ERR_IO);
1277 				goto done;
1278 			}
1279 			n = fprintf(tmpf, "%s\n", re->ref->ref.ref.name);
1280 			if (n != strlen(re->ref->ref.ref.name) + 1) {
1281 				err = got_ferror(f, GOT_ERR_IO);
1282 				goto done;
1283 			}
1284 		}
1285 
1286 		if (fflush(tmpf) != 0) {
1287 			err = got_error_from_errno("fflush");
1288 			goto done;
1289 		}
1290 
1291 		if (stat(packed_refs_path, &sb) != 0) {
1292 			if (errno != ENOENT) {
1293 				err = got_error_from_errno2("stat",
1294 				    packed_refs_path);
1295 				goto done;
1296 			}
1297 			sb.st_mode = GOT_DEFAULT_FILE_MODE;
1298 		}
1299 
1300 		if (rename(tmppath, packed_refs_path) != 0) {
1301 			err = got_error_from_errno3("rename", tmppath,
1302 			    packed_refs_path);
1303 			goto done;
1304 		}
1305 
1306 		if (chmod(packed_refs_path, sb.st_mode) != 0) {
1307 			err = got_error_from_errno2("chmod",
1308 			    packed_refs_path);
1309 			goto done;
1310 		}
1311 	}
1312 done:
1313 	if (delref->lf == NULL && lf)
1314 		unlock_err = got_lockfile_unlock(lf);
1315 	if (f) {
1316 		if (fclose(f) != 0 && err == NULL)
1317 			err = got_error_from_errno("fclose");
1318 	}
1319 	if (tmpf) {
1320 		unlink(tmppath);
1321 		if (fclose(tmpf) != 0 && err == NULL)
1322 			err = got_error_from_errno("fclose");
1323 	}
1324 	free(tmppath);
1325 	free(packed_refs_path);
1326 	got_ref_list_free(&refs);
1327 	return err ? err : unlock_err;
1328 }
1329 
1330 const struct got_error *
1331 got_ref_delete(struct got_reference *ref, struct got_repository *repo)
1332 {
1333 	const struct got_error *err = NULL, *unlock_err = NULL;
1334 	const char *name = got_ref_get_name(ref);
1335 	char *path_refs = NULL, *path = NULL;
1336 	struct got_lockfile *lf = NULL;
1337 
1338 	if (ref->flags & GOT_REF_IS_PACKED)
1339 		return delete_packed_ref(ref, repo);
1340 
1341 	path_refs = get_refs_dir_path(repo, name);
1342 	if (path_refs == NULL) {
1343 		err = got_error_from_errno2("get_refs_dir_path", name);
1344 		goto done;
1345 	}
1346 
1347 	if (asprintf(&path, "%s/%s", path_refs, name) == -1) {
1348 		err = got_error_from_errno("asprintf");
1349 		goto done;
1350 	}
1351 
1352 	if (ref->lf == NULL) {
1353 		err = got_lockfile_lock(&lf, path);
1354 		if (err)
1355 			goto done;
1356 	}
1357 
1358 	/* XXX: check if old content matches our expectations? */
1359 
1360 	if (unlink(path) != 0)
1361 		err = got_error_from_errno2("unlink", path);
1362 done:
1363 	if (ref->lf == NULL && lf)
1364 		unlock_err = got_lockfile_unlock(lf);
1365 
1366 	free(path_refs);
1367 	free(path);
1368 	return err ? err : unlock_err;
1369 }
1370 
1371 const struct got_error *
1372 got_ref_unlock(struct got_reference *ref)
1373 {
1374 	const struct got_error *err;
1375 	err = got_lockfile_unlock(ref->lf);
1376 	ref->lf = NULL;
1377 	return err;
1378 }