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/stat.h>
19 #include <sys/queue.h>
20 #include <sys/tree.h>
21 #include <sys/uio.h>
22 #include <sys/mman.h>
23 
24 #include <errno.h>
25 #include <fcntl.h>
26 #include <stdio.h>
27 #include <stdlib.h>
28 #include <string.h>
29 #include <sha1.h>
30 #include <unistd.h>
31 #include <zlib.h>
32 #include <libgen.h>
33 #include <limits.h>
34 #include <imsg.h>
35 
36 #include "got_error.h"
37 #include "got_object.h"
38 #include "got_repository.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_privsep.h"
47 #include "got_lib_object_idcache.h"
48 #include "got_lib_object_cache.h"
49 #include "got_lib_object_parse.h"
50 #include "got_lib_pack.h"
51 #include "got_lib_repository.h"
52 
53 #ifndef MIN
54 #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
55 #endif
56 
57 #ifndef nitems
58 #define nitems(_a)	(sizeof((_a)) / sizeof((_a)[0]))
59 #endif
60 
61 struct got_object_id *
62 got_object_get_id(struct got_object *obj)
63 {
64 	return &obj->id;
65 }
66 
67 const struct got_error *
68 got_object_get_id_str(char **outbuf, struct got_object *obj)
69 {
70 	return got_object_id_str(outbuf, &obj->id);
71 }
72 
73 const struct got_error *
74 got_object_get_type(int *type, struct got_repository *repo,
75     struct got_object_id *id)
76 {
77 	const struct got_error *err = NULL;
78 	struct got_object *obj;
79 
80 	err = got_object_open(&obj, repo, id);
81 	if (err)
82 		return err;
83 
84 	switch (obj->type) {
85 	case GOT_OBJ_TYPE_COMMIT:
86 	case GOT_OBJ_TYPE_TREE:
87 	case GOT_OBJ_TYPE_BLOB:
88 	case GOT_OBJ_TYPE_TAG:
89 		*type = obj->type;
90 		break;
91 	default:
92 		err = got_error(GOT_ERR_OBJ_TYPE);
93 		break;
94 	}
95 
96 	got_object_close(obj);
97 	return err;
98 }
99 
100 const struct got_error *
101 got_object_get_path(char **path, struct got_object_id *id,
102     struct got_repository *repo)
103 {
104 	const struct got_error *err = NULL;
105 	char *hex = NULL;
106 	char *path_objects;
107 
108 	*path = NULL;
109 
110 	path_objects = got_repo_get_path_objects(repo);
111 	if (path_objects == NULL)
112 		return got_error_from_errno("got_repo_get_path_objects");
113 
114 	err = got_object_id_str(&hex, id);
115 	if (err)
116 		goto done;
117 
118 	if (asprintf(path, "%s/%.2x/%s", path_objects,
119 	    id->sha1[0], hex + 2) == -1)
120 		err = got_error_from_errno("asprintf");
121 
122 done:
123 	free(hex);
124 	free(path_objects);
125 	return err;
126 }
127 
128 const struct got_error *
129 got_object_open_loose_fd(int *fd, struct got_object_id *id,
130     struct got_repository *repo)
131 {
132 	const struct got_error *err = NULL;
133 	char *path;
134 
135 	err = got_object_get_path(&path, id, repo);
136 	if (err)
137 		return err;
138 	*fd = open(path, O_RDONLY | O_NOFOLLOW | O_CLOEXEC);
139 	if (*fd == -1) {
140 		err = got_error_from_errno2("open", path);
141 		goto done;
142 	}
143 done:
144 	free(path);
145 	return err;
146 }
147 
148 const struct got_error *
149 got_object_open_by_id_str(struct got_object **obj, struct got_repository *repo,
150     const char *id_str)
151 {
152 	struct got_object_id id;
153 
154 	if (!got_parse_sha1_digest(id.sha1, id_str))
155 		return got_error_path(id_str, GOT_ERR_BAD_OBJ_ID_STR);
156 
157 	return got_object_open(obj, repo, &id);
158 }
159 
160 const struct got_error *
161 got_object_resolve_id_str(struct got_object_id **id,
162     struct got_repository *repo, const char *id_str)
163 {
164 	const struct got_error *err = NULL;
165 	struct got_object *obj;
166 
167 	err = got_object_open_by_id_str(&obj, repo, id_str);
168 	if (err)
169 		return err;
170 
171 	*id = got_object_id_dup(got_object_get_id(obj));
172 	got_object_close(obj);
173 	if (*id == NULL)
174 		return got_error_from_errno("got_object_id_dup");
175 
176 	return NULL;
177 }
178 
179 const struct got_error *
180 got_object_qid_alloc(struct got_object_qid **qid, struct got_object_id *id)
181 {
182 	*qid = calloc(1, sizeof(**qid));
183 	if (*qid == NULL)
184 		return got_error_from_errno("calloc");
185 
186 	memcpy(&(*qid)->id, id, sizeof((*qid)->id));
187 	return NULL;
188 }
189 
190 const struct got_error *
191 got_object_id_queue_copy(const struct got_object_id_queue *src,
192     struct got_object_id_queue *dest)
193 {
194 	const struct got_error *err;
195 	struct got_object_qid *qid;
196 
197 	STAILQ_FOREACH(qid, src, entry) {
198 		struct got_object_qid *new;
199 		/*
200 		 * Deep-copy the object ID only. Let the caller deal
201 		 * with setting up the new->data pointer if needed.
202 		 */
203 		err = got_object_qid_alloc(&new, &qid->id);
204 		if (err) {
205 			got_object_id_queue_free(dest);
206 			return err;
207 		}
208 		STAILQ_INSERT_TAIL(dest, new, entry);
209 	}
210 
211 	return NULL;
212 }
213 
214 int
215 got_object_tree_get_nentries(struct got_tree_object *tree)
216 {
217 	return tree->nentries;
218 }
219 
220 struct got_tree_entry *
221 got_object_tree_get_first_entry(struct got_tree_object *tree)
222 {
223 	return got_object_tree_get_entry(tree, 0);
224 }
225 
226 struct got_tree_entry *
227 got_object_tree_get_last_entry(struct got_tree_object *tree)
228 {
229 	return got_object_tree_get_entry(tree, tree->nentries - 1);
230 }
231 
232 struct got_tree_entry *
233 got_object_tree_get_entry(struct got_tree_object *tree, int i)
234 {
235 	if (i < 0 || i >= tree->nentries)
236 		return NULL;
237 	return &tree->entries[i];
238 }
239 
240 mode_t
241 got_tree_entry_get_mode(struct got_tree_entry *te)
242 {
243 	return te->mode;
244 }
245 
246 const char *
247 got_tree_entry_get_name(struct got_tree_entry *te)
248 {
249 	return &te->name[0];
250 }
251 
252 struct got_object_id *
253 got_tree_entry_get_id(struct got_tree_entry *te)
254 {
255 	return &te->id;
256 }
257 
258 const struct got_error *
259 got_object_blob_read_to_str(char **s, struct got_blob_object *blob)
260 {
261 	const struct got_error *err = NULL;
262 	size_t len, totlen, hdrlen, offset;
263 
264 	*s = NULL;
265 
266 	hdrlen = got_object_blob_get_hdrlen(blob);
267 	totlen = 0;
268 	offset = 0;
269 	do {
270 		char *p;
271 
272 		err = got_object_blob_read_block(&len, blob);
273 		if (err)
274 			return err;
275 
276 		if (len == 0)
277 			break;
278 
279 		totlen += len - hdrlen;
280 		p = realloc(*s, totlen + 1);
281 		if (p == NULL) {
282 			err = got_error_from_errno("realloc");
283 			free(*s);
284 			*s = NULL;
285 			return err;
286 		}
287 		*s = p;
288 		/* Skip blob object header first time around. */
289 		memcpy(*s + offset,
290 		    got_object_blob_get_read_buf(blob) + hdrlen, len - hdrlen);
291 		hdrlen = 0;
292 		offset = totlen;
293 	} while (len > 0);
294 
295 	(*s)[totlen] = '\0';
296 	return NULL;
297 }
298 
299 const struct got_error *
300 got_tree_entry_get_symlink_target(char **link_target, struct got_tree_entry *te,
301     struct got_repository *repo)
302 {
303 	const struct got_error *err = NULL;
304 	struct got_blob_object *blob = NULL;
305 	int fd = -1;
306 
307 	*link_target = NULL;
308 
309 	if (!got_object_tree_entry_is_symlink(te))
310 		return got_error(GOT_ERR_TREE_ENTRY_TYPE);
311 
312 	fd = got_opentempfd();
313 	if (fd == -1) {
314 		err = got_error_from_errno("got_opentempfd");
315 		goto done;
316 	}
317 
318 	err = got_object_open_as_blob(&blob, repo,
319 	    got_tree_entry_get_id(te), PATH_MAX, fd);
320 	if (err)
321 		goto done;
322 
323 	err = got_object_blob_read_to_str(link_target, blob);
324 done:
325 	if (fd != -1 && close(fd) == -1 && err == NULL)
326 		err = got_error_from_errno("close");
327 	if (blob)
328 		got_object_blob_close(blob);
329 	if (err) {
330 		free(*link_target);
331 		*link_target = NULL;
332 	}
333 	return err;
334 }
335 
336 int
337 got_tree_entry_get_index(struct got_tree_entry *te)
338 {
339 	return te->idx;
340 }
341 
342 struct got_tree_entry *
343 got_tree_entry_get_next(struct got_tree_object *tree,
344     struct got_tree_entry *te)
345 {
346 	return got_object_tree_get_entry(tree, te->idx + 1);
347 }
348 
349 struct got_tree_entry *
350 got_tree_entry_get_prev(struct got_tree_object *tree,
351     struct got_tree_entry *te)
352 {
353 	return got_object_tree_get_entry(tree, te->idx - 1);
354 }
355 
356 const struct got_error *
357 got_object_blob_close(struct got_blob_object *blob)
358 {
359 	const struct got_error *err = NULL;
360 	free(blob->read_buf);
361 	if (blob->f && fclose(blob->f) == EOF)
362 		err = got_error_from_errno("fclose");
363 	free(blob->data);
364 	free(blob);
365 	return err;
366 }
367 
368 void
369 got_object_blob_rewind(struct got_blob_object *blob)
370 {
371 	if (blob->f)
372 		rewind(blob->f);
373 }
374 
375 char *
376 got_object_blob_id_str(struct got_blob_object *blob, char *buf, size_t size)
377 {
378 	return got_sha1_digest_to_str(blob->id.sha1, buf, size);
379 }
380 
381 size_t
382 got_object_blob_get_hdrlen(struct got_blob_object *blob)
383 {
384 	return blob->hdrlen;
385 }
386 
387 const uint8_t *
388 got_object_blob_get_read_buf(struct got_blob_object *blob)
389 {
390 	return blob->read_buf;
391 }
392 
393 const struct got_error *
394 got_object_blob_read_block(size_t *outlenp, struct got_blob_object *blob)
395 {
396 	size_t n;
397 
398 	n = fread(blob->read_buf, 1, blob->blocksize, blob->f);
399 	if (n == 0 && ferror(blob->f))
400 		return got_ferror(blob->f, GOT_ERR_IO);
401 	*outlenp = n;
402 	return NULL;
403 }
404 
405 const struct got_error *
406 got_object_blob_dump_to_file(off_t *filesize, int *nlines,
407     off_t **line_offsets, FILE *outfile, struct got_blob_object *blob)
408 {
409 	const struct got_error *err = NULL;
410 	size_t n, len, hdrlen;
411 	const uint8_t *buf;
412 	int i;
413 	const int alloc_chunksz = 512;
414 	size_t nalloc = 0;
415 	off_t off = 0, total_len = 0;
416 
417 	if (line_offsets)
418 		*line_offsets = NULL;
419 	if (filesize)
420 		*filesize = 0;
421 	if (nlines)
422 		*nlines = 0;
423 
424 	hdrlen = got_object_blob_get_hdrlen(blob);
425 	do {
426 		err = got_object_blob_read_block(&len, blob);
427 		if (err)
428 			return err;
429 		if (len == 0)
430 			break;
431 		buf = got_object_blob_get_read_buf(blob);
432 		i = hdrlen;
433 		if (nlines) {
434 			if (line_offsets && *line_offsets == NULL) {
435 				/* Have some data but perhaps no '\n'. */
436 				*nlines = 1;
437 				nalloc = alloc_chunksz;
438 				*line_offsets = calloc(nalloc,
439 				    sizeof(**line_offsets));
440 				if (*line_offsets == NULL)
441 					return got_error_from_errno("calloc");
442 
443 				/* Skip forward over end of first line. */
444 				while (i < len) {
445 					if (buf[i] == '\n')
446 						break;
447 					i++;
448 				}
449 			}
450 			/* Scan '\n' offsets in remaining chunk of data. */
451 			while (i < len) {
452 				if (buf[i] != '\n') {
453 					i++;
454 					continue;
455 				}
456 				(*nlines)++;
457 				if (line_offsets && nalloc < *nlines) {
458 					size_t n = *nlines + alloc_chunksz;
459 					off_t *o = recallocarray(*line_offsets,
460 					    nalloc, n, sizeof(**line_offsets));
461 					if (o == NULL) {
462 						free(*line_offsets);
463 						*line_offsets = NULL;
464 						return got_error_from_errno(
465 						    "recallocarray");
466 					}
467 					*line_offsets = o;
468 					nalloc = n;
469 				}
470 				if (line_offsets) {
471 					off = total_len + i - hdrlen + 1;
472 					(*line_offsets)[*nlines - 1] = off;
473 				}
474 				i++;
475 			}
476 		}
477 		/* Skip blob object header first time around. */
478 		n = fwrite(buf + hdrlen, 1, len - hdrlen, outfile);
479 		if (n != len - hdrlen)
480 			return got_ferror(outfile, GOT_ERR_IO);
481 		total_len += len - hdrlen;
482 		hdrlen = 0;
483 	} while (len != 0);
484 
485 	if (fflush(outfile) != 0)
486 		return got_error_from_errno("fflush");
487 	rewind(outfile);
488 
489 	if (filesize)
490 		*filesize = total_len;
491 
492 	return NULL;
493 }
494 
495 const char *
496 got_object_tag_get_name(struct got_tag_object *tag)
497 {
498 	return tag->tag;
499 }
500 
501 int
502 got_object_tag_get_object_type(struct got_tag_object *tag)
503 {
504 	return tag->obj_type;
505 }
506 
507 struct got_object_id *
508 got_object_tag_get_object_id(struct got_tag_object *tag)
509 {
510 	return &tag->id;
511 }
512 
513 time_t
514 got_object_tag_get_tagger_time(struct got_tag_object *tag)
515 {
516 	return tag->tagger_time;
517 }
518 
519 time_t
520 got_object_tag_get_tagger_gmtoff(struct got_tag_object *tag)
521 {
522 	return tag->tagger_gmtoff;
523 }
524 
525 const char *
526 got_object_tag_get_tagger(struct got_tag_object *tag)
527 {
528 	return tag->tagger;
529 }
530 
531 const char *
532 got_object_tag_get_message(struct got_tag_object *tag)
533 {
534 	return tag->tagmsg;
535 }
536 
537 static struct got_tree_entry *
538 find_entry_by_name(struct got_tree_object *tree, const char *name, size_t len)
539 {
540 	int i;
541 
542 	/* Note that tree entries are sorted in strncmp() order. */
543 	for (i = 0; i < tree->nentries; i++) {
544 		struct got_tree_entry *te = &tree->entries[i];
545 		int cmp = strncmp(te->name, name, len);
546 		if (cmp < 0)
547 			continue;
548 		if (cmp > 0)
549 			break;
550 		if (te->name[len] == '\0')
551 			return te;
552 	}
553 	return NULL;
554 }
555 
556 struct got_tree_entry *
557 got_object_tree_find_entry(struct got_tree_object *tree, const char *name)
558 {
559 	return find_entry_by_name(tree, name, strlen(name));
560 }
561 
562 const struct got_error *
563 got_object_tree_find_path(struct got_object_id **id, mode_t *mode,
564     struct got_repository *repo, struct got_tree_object *tree,
565     const char *path)
566 {
567 	const struct got_error *err = NULL;
568 	struct got_tree_object *subtree = NULL;
569 	struct got_tree_entry *te = NULL;
570 	const char *seg, *s;
571 	size_t seglen;
572 
573 	*id = NULL;
574 
575 	s = path;
576 	while (s[0] == '/')
577 		s++;
578 	seg = s;
579 	seglen = 0;
580 	subtree = tree;
581 	while (*s) {
582 		struct got_tree_object *next_tree;
583 
584 		if (*s != '/') {
585 			s++;
586 			seglen++;
587 			if (*s)
588 				continue;
589 		}
590 
591 		te = find_entry_by_name(subtree, seg, seglen);
592 		if (te == NULL) {
593 			err = got_error_path(path, GOT_ERR_NO_TREE_ENTRY);
594 			goto done;
595 		}
596 
597 		if (*s == '\0')
598 			break;
599 
600 		seg = s + 1;
601 		seglen = 0;
602 		s++;
603 		if (*s) {
604 			err = got_object_open_as_tree(&next_tree, repo,
605 			    &te->id);
606 			te = NULL;
607 			if (err)
608 				goto done;
609 			if (subtree != tree)
610 				got_object_tree_close(subtree);
611 			subtree = next_tree;
612 		}
613 	}
614 
615 	if (te) {
616 		*id = got_object_id_dup(&te->id);
617 		if (*id == NULL)
618 			return got_error_from_errno("got_object_id_dup");
619 		if (mode)
620 			*mode = te->mode;
621 	} else
622 		err = got_error_path(path, GOT_ERR_NO_TREE_ENTRY);
623 done:
624 	if (subtree && subtree != tree)
625 		got_object_tree_close(subtree);
626 	return err;
627 }
628 
629 const struct got_error *
630 got_object_id_by_path(struct got_object_id **id, struct got_repository *repo,
631     struct got_commit_object *commit, const char *path)
632 {
633 	const struct got_error *err = NULL;
634 	struct got_tree_object *tree = NULL;
635 
636 	*id = NULL;
637 
638 	/* Handle opening of root of commit's tree. */
639 	if (got_path_is_root_dir(path)) {
640 		*id = got_object_id_dup(commit->tree_id);
641 		if (*id == NULL)
642 			err = got_error_from_errno("got_object_id_dup");
643 	} else {
644 		err = got_object_open_as_tree(&tree, repo, commit->tree_id);
645 		if (err)
646 			goto done;
647 		err = got_object_tree_find_path(id, NULL, repo, tree, path);
648 	}
649 done:
650 	if (tree)
651 		got_object_tree_close(tree);
652 	return err;
653 }
654 
655 /*
656  * Normalize file mode bits to avoid false positive tree entry differences
657  * in case tree entries have unexpected mode bits set.
658  */
659 static mode_t
660 normalize_mode_for_comparison(mode_t mode)
661 {
662 	/*
663 	 * For directories, the only relevant bit is the IFDIR bit.
664 	 * This allows us to detect paths changing from a directory
665 	 * to a file and vice versa.
666 	 */
667 	if (S_ISDIR(mode))
668 		return mode & S_IFDIR;
669 
670 	/*
671 	 * For symlinks, the only relevant bit is the IFLNK bit.
672 	 * This allows us to detect paths changing from a symlinks
673 	 * to a file or directory and vice versa.
674 	 */
675 	if (S_ISLNK(mode))
676 		return mode & S_IFLNK;
677 
678 	/* For files, the only change we care about is the executable bit. */
679 	return mode & S_IXUSR;
680 }
681 
682 const struct got_error *
683 got_object_tree_path_changed(int *changed,
684     struct got_tree_object *tree01, struct got_tree_object *tree02,
685     const char *path, struct got_repository *repo)
686 {
687 	const struct got_error *err = NULL;
688 	struct got_tree_object *tree1 = NULL, *tree2 = NULL;
689 	struct got_tree_entry *te1 = NULL, *te2 = NULL;
690 	const char *seg, *s;
691 	size_t seglen;
692 
693 	*changed = 0;
694 
695 	/* We not do support comparing the root path. */
696 	if (got_path_is_root_dir(path))
697 		return got_error_path(path, GOT_ERR_BAD_PATH);
698 
699 	tree1 = tree01;
700 	tree2 = tree02;
701 	s = path;
702 	while (*s == '/')
703 		s++;
704 	seg = s;
705 	seglen = 0;
706 	while (*s) {
707 		struct got_tree_object *next_tree1, *next_tree2;
708 		mode_t mode1, mode2;
709 
710 		if (*s != '/') {
711 			s++;
712 			seglen++;
713 			if (*s)
714 				continue;
715 		}
716 
717 		te1 = find_entry_by_name(tree1, seg, seglen);
718 		if (te1 == NULL) {
719 			err = got_error(GOT_ERR_NO_OBJ);
720 			goto done;
721 		}
722 
723 		if (tree2)
724 			te2 = find_entry_by_name(tree2, seg, seglen);
725 
726 		if (te2) {
727 			mode1 = normalize_mode_for_comparison(te1->mode);
728 			mode2 = normalize_mode_for_comparison(te2->mode);
729 			if (mode1 != mode2) {
730 				*changed = 1;
731 				goto done;
732 			}
733 
734 			if (got_object_id_cmp(&te1->id, &te2->id) == 0) {
735 				*changed = 0;
736 				goto done;
737 			}
738 		}
739 
740 		if (*s == '\0') { /* final path element */
741 			*changed = 1;
742 			goto done;
743 		}
744 
745 		seg = s + 1;
746 		s++;
747 		seglen = 0;
748 		if (*s) {
749 			err = got_object_open_as_tree(&next_tree1, repo,
750 			    &te1->id);
751 			te1 = NULL;
752 			if (err)
753 				goto done;
754 			if (tree1 != tree01)
755 				got_object_tree_close(tree1);
756 			tree1 = next_tree1;
757 
758 			if (te2) {
759 				err = got_object_open_as_tree(&next_tree2, repo,
760 				    &te2->id);
761 				te2 = NULL;
762 				if (err)
763 					goto done;
764 				if (tree2 != tree02)
765 					got_object_tree_close(tree2);
766 				tree2 = next_tree2;
767 			} else if (tree2) {
768 				if (tree2 != tree02)
769 					got_object_tree_close(tree2);
770 				tree2 = NULL;
771 			}
772 		}
773 	}
774 done:
775 	if (tree1 && tree1 != tree01)
776 		got_object_tree_close(tree1);
777 	if (tree2 && tree2 != tree02)
778 		got_object_tree_close(tree2);
779 	return err;
780 }
781 
782 const struct got_error *
783 got_object_tree_entry_dup(struct got_tree_entry **new_te,
784     struct got_tree_entry *te)
785 {
786 	const struct got_error *err = NULL;
787 
788 	*new_te = calloc(1, sizeof(**new_te));
789 	if (*new_te == NULL)
790 		return got_error_from_errno("calloc");
791 
792 	(*new_te)->mode = te->mode;
793 	memcpy((*new_te)->name, te->name, sizeof((*new_te)->name));
794 	memcpy(&(*new_te)->id, &te->id, sizeof((*new_te)->id));
795 	return err;
796 }
797 
798 int
799 got_object_tree_entry_is_submodule(struct got_tree_entry *te)
800 {
801 	return (te->mode & S_IFMT) == (S_IFDIR | S_IFLNK);
802 }
803 
804 int
805 got_object_tree_entry_is_symlink(struct got_tree_entry *te)
806 {
807 	/* S_IFDIR check avoids confusing symlinks with submodules. */
808 	return ((te->mode & (S_IFDIR | S_IFLNK)) == S_IFLNK);
809 }
810 
811 static const struct got_error *
812 resolve_symlink(char **link_target, const char *path,
813     struct got_commit_object *commit, struct got_repository *repo)
814 {
815 	const struct got_error *err = NULL;
816 	char buf[PATH_MAX];
817 	char *name, *parent_path = NULL;
818 	struct got_object_id *tree_obj_id = NULL;
819 	struct got_tree_object *tree = NULL;
820 	struct got_tree_entry *te = NULL;
821 
822 	*link_target = NULL;
823 
824 	if (strlcpy(buf, path, sizeof(buf)) >= sizeof(buf))
825 		return got_error(GOT_ERR_NO_SPACE);
826 
827 	name = basename(buf);
828 	if (name == NULL)
829 		return got_error_from_errno2("basename", path);
830 
831 	err = got_path_dirname(&parent_path, path);
832 	if (err)
833 		return err;
834 
835 	err = got_object_id_by_path(&tree_obj_id, repo, commit,
836 	    parent_path);
837 	if (err) {
838 		if (err->code == GOT_ERR_NO_TREE_ENTRY) {
839 			/* Display the complete path in error message. */
840 			err = got_error_path(path, err->code);
841 		}
842 		goto done;
843 	}
844 
845 	err = got_object_open_as_tree(&tree, repo, tree_obj_id);
846 	if (err)
847 		goto done;
848 
849 	te = got_object_tree_find_entry(tree, name);
850 	if (te == NULL) {
851 		err = got_error_path(path, GOT_ERR_NO_TREE_ENTRY);
852 		goto done;
853 	}
854 
855 	if (got_object_tree_entry_is_symlink(te)) {
856 		err = got_tree_entry_get_symlink_target(link_target, te, repo);
857 		if (err)
858 			goto done;
859 		if (!got_path_is_absolute(*link_target)) {
860 			char *abspath;
861 			if (asprintf(&abspath, "%s/%s", parent_path,
862 			    *link_target) == -1) {
863 				err = got_error_from_errno("asprintf");
864 				goto done;
865 			}
866 			free(*link_target);
867 			*link_target = malloc(PATH_MAX);
868 			if (*link_target == NULL) {
869 				err = got_error_from_errno("malloc");
870 				goto done;
871 			}
872 			err = got_canonpath(abspath, *link_target, PATH_MAX);
873 			free(abspath);
874 			if (err)
875 				goto done;
876 		}
877 	}
878 done:
879 	free(parent_path);
880 	free(tree_obj_id);
881 	if (tree)
882 		got_object_tree_close(tree);
883 	if (err) {
884 		free(*link_target);
885 		*link_target = NULL;
886 	}
887 	return err;
888 }
889 
890 const struct got_error *
891 got_object_resolve_symlinks(char **link_target, const char *path,
892     struct got_commit_object *commit, struct got_repository *repo)
893 {
894 	const struct got_error *err = NULL;
895 	char *next_target = NULL;
896 	int max_recursion = 40; /* matches Git */
897 
898 	*link_target = NULL;
899 
900 	do {
901 		err = resolve_symlink(&next_target,
902 		    *link_target ? *link_target : path, commit, repo);
903 		if (err)
904 			break;
905 		if (next_target) {
906 			free(*link_target);
907 			if (--max_recursion == 0) {
908 				err = got_error_path(path, GOT_ERR_RECURSION);
909 				*link_target = NULL;
910 				break;
911 			}
912 			*link_target = next_target;
913 		}
914 	} while (next_target);
915 
916 	return err;
917 }
918 
919 void
920 got_object_commit_retain(struct got_commit_object *commit)
921 {
922 	commit->refcnt++;
923 }