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 "got_compat.h"
18 
19 #include <sys/types.h>
20 #include <sys/stat.h>
21 #include <sys/queue.h>
22 #include <sys/uio.h>
23 #include <sys/mman.h>
24 
25 #include <errno.h>
26 #include <fcntl.h>
27 #include <stdio.h>
28 #include <stdlib.h>
29 #include <string.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_hash.h"
43 #include "got_lib_delta.h"
44 #include "got_lib_inflate.h"
45 #include "got_lib_object.h"
46 #include "got_lib_object_idcache.h"
47 #include "got_lib_object_cache.h"
48 #include "got_lib_object_parse.h"
49 #include "got_lib_pack.h"
50 #include "got_lib_repository.h"
51 
52 #ifndef MIN
53 #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
54 #endif
55 
56 #ifndef nitems
57 #define nitems(_a)	(sizeof((_a)) / sizeof((_a)[0]))
58 #endif
59 
60 struct got_object_id *
61 got_object_get_id(struct got_object *obj)
62 {
63 	return &obj->id;
64 }
65 
66 const struct got_error *
67 got_object_get_id_str(char **outbuf, struct got_object *obj)
68 {
69 	return got_object_id_str(outbuf, &obj->id);
70 }
71 
72 const struct got_error *
73 got_object_get_type(int *type, struct got_repository *repo,
74     struct got_object_id *id)
75 {
76 	const struct got_error *err = NULL;
77 	struct got_object *obj;
78 
79 	err = got_object_open(&obj, repo, id);
80 	if (err)
81 		return err;
82 
83 	switch (obj->type) {
84 	case GOT_OBJ_TYPE_COMMIT:
85 	case GOT_OBJ_TYPE_TREE:
86 	case GOT_OBJ_TYPE_BLOB:
87 	case GOT_OBJ_TYPE_TAG:
88 		*type = obj->type;
89 		break;
90 	default:
91 		err = got_error(GOT_ERR_OBJ_TYPE);
92 		break;
93 	}
94 
95 	got_object_close(obj);
96 	return err;
97 }
98 
99 const struct got_error *
100 got_object_get_path(char **path, struct got_object_id *id,
101     struct got_repository *repo)
102 {
103 	const struct got_error *err = NULL;
104 	char *hex = NULL;
105 	char *path_objects;
106 
107 	*path = NULL;
108 
109 	path_objects = got_repo_get_path_objects(repo);
110 	if (path_objects == NULL)
111 		return got_error_from_errno("got_repo_get_path_objects");
112 
113 	err = got_object_id_str(&hex, id);
114 	if (err)
115 		goto done;
116 
117 	if (asprintf(path, "%s/%.2x/%s", path_objects,
118 	    id->sha1[0], hex + 2) == -1)
119 		err = got_error_from_errno("asprintf");
120 
121 done:
122 	free(hex);
123 	free(path_objects);
124 	return err;
125 }
126 
127 const struct got_error *
128 got_object_open_loose_fd(int *fd, struct got_object_id *id,
129     struct got_repository *repo)
130 {
131 	const struct got_error *err = NULL;
132 	char *path;
133 
134 	err = got_object_get_path(&path, id, repo);
135 	if (err)
136 		return err;
137 	*fd = open(path, O_RDONLY | O_NOFOLLOW | O_CLOEXEC);
138 	if (*fd == -1) {
139 		err = got_error_from_errno2("open", path);
140 		goto done;
141 	}
142 done:
143 	free(path);
144 	return err;
145 }
146 
147 const struct got_error *
148 got_object_open_by_id_str(struct got_object **obj, struct got_repository *repo,
149     const char *id_str)
150 {
151 	struct got_object_id id;
152 
153 	if (!got_parse_object_id(&id, id_str, GOT_HASH_SHA1))
154 		return got_error_path(id_str, GOT_ERR_BAD_OBJ_ID_STR);
155 
156 	return got_object_open(obj, repo, &id);
157 }
158 
159 const struct got_error *
160 got_object_resolve_id_str(struct got_object_id **id,
161     struct got_repository *repo, const char *id_str)
162 {
163 	const struct got_error *err = NULL;
164 	struct got_object *obj;
165 
166 	err = got_object_open_by_id_str(&obj, repo, id_str);
167 	if (err)
168 		return err;
169 
170 	*id = got_object_id_dup(got_object_get_id(obj));
171 	got_object_close(obj);
172 	if (*id == NULL)
173 		return got_error_from_errno("got_object_id_dup");
174 
175 	return NULL;
176 }
177 
178 int
179 got_object_tree_get_nentries(struct got_tree_object *tree)
180 {
181 	return tree->nentries;
182 }
183 
184 struct got_tree_entry *
185 got_object_tree_get_first_entry(struct got_tree_object *tree)
186 {
187 	return got_object_tree_get_entry(tree, 0);
188 }
189 
190 struct got_tree_entry *
191 got_object_tree_get_last_entry(struct got_tree_object *tree)
192 {
193 	return got_object_tree_get_entry(tree, tree->nentries - 1);
194 }
195 
196 struct got_tree_entry *
197 got_object_tree_get_entry(struct got_tree_object *tree, int i)
198 {
199 	if (i < 0 || i >= tree->nentries)
200 		return NULL;
201 	return &tree->entries[i];
202 }
203 
204 mode_t
205 got_tree_entry_get_mode(struct got_tree_entry *te)
206 {
207 	return te->mode;
208 }
209 
210 const char *
211 got_tree_entry_get_name(struct got_tree_entry *te)
212 {
213 	return &te->name[0];
214 }
215 
216 struct got_object_id *
217 got_tree_entry_get_id(struct got_tree_entry *te)
218 {
219 	return &te->id;
220 }
221 
222 const struct got_error *
223 got_object_blob_read_to_str(char **s, struct got_blob_object *blob)
224 {
225 	const struct got_error *err = NULL;
226 	size_t len, totlen, hdrlen, offset;
227 
228 	*s = NULL;
229 
230 	hdrlen = got_object_blob_get_hdrlen(blob);
231 	totlen = 0;
232 	offset = 0;
233 	do {
234 		char *p;
235 
236 		err = got_object_blob_read_block(&len, blob);
237 		if (err)
238 			return err;
239 
240 		if (len == 0)
241 			break;
242 
243 		totlen += len - hdrlen;
244 		p = realloc(*s, totlen + 1);
245 		if (p == NULL) {
246 			err = got_error_from_errno("realloc");
247 			free(*s);
248 			*s = NULL;
249 			return err;
250 		}
251 		*s = p;
252 		/* Skip blob object header first time around. */
253 		memcpy(*s + offset,
254 		    got_object_blob_get_read_buf(blob) + hdrlen, len - hdrlen);
255 		hdrlen = 0;
256 		offset = totlen;
257 	} while (len > 0);
258 
259 	(*s)[totlen] = '\0';
260 	return NULL;
261 }
262 
263 const struct got_error *
264 got_tree_entry_get_symlink_target(char **link_target, struct got_tree_entry *te,
265     struct got_repository *repo)
266 {
267 	const struct got_error *err = NULL;
268 	struct got_blob_object *blob = NULL;
269 	int fd = -1;
270 
271 	*link_target = NULL;
272 
273 	if (!got_object_tree_entry_is_symlink(te))
274 		return got_error(GOT_ERR_TREE_ENTRY_TYPE);
275 
276 	fd = got_opentempfd();
277 	if (fd == -1) {
278 		err = got_error_from_errno("got_opentempfd");
279 		goto done;
280 	}
281 
282 	err = got_object_open_as_blob(&blob, repo,
283 	    got_tree_entry_get_id(te), PATH_MAX, fd);
284 	if (err)
285 		goto done;
286 
287 	err = got_object_blob_read_to_str(link_target, blob);
288 done:
289 	if (fd != -1 && close(fd) == -1 && err == NULL)
290 		err = got_error_from_errno("close");
291 	if (blob)
292 		got_object_blob_close(blob);
293 	if (err) {
294 		free(*link_target);
295 		*link_target = NULL;
296 	}
297 	return err;
298 }
299 
300 int
301 got_tree_entry_get_index(struct got_tree_entry *te)
302 {
303 	return te->idx;
304 }
305 
306 struct got_tree_entry *
307 got_tree_entry_get_next(struct got_tree_object *tree,
308     struct got_tree_entry *te)
309 {
310 	return got_object_tree_get_entry(tree, te->idx + 1);
311 }
312 
313 struct got_tree_entry *
314 got_tree_entry_get_prev(struct got_tree_object *tree,
315     struct got_tree_entry *te)
316 {
317 	return got_object_tree_get_entry(tree, te->idx - 1);
318 }
319 
320 const struct got_error *
321 got_object_blob_close(struct got_blob_object *blob)
322 {
323 	const struct got_error *err = NULL;
324 	free(blob->read_buf);
325 	if (blob->f && fclose(blob->f) == EOF)
326 		err = got_error_from_errno("fclose");
327 	free(blob->data);
328 	free(blob);
329 	return err;
330 }
331 
332 void
333 got_object_blob_rewind(struct got_blob_object *blob)
334 {
335 	if (blob->f)
336 		rewind(blob->f);
337 }
338 
339 char *
340 got_object_blob_id_str(struct got_blob_object *blob, char *buf, size_t size)
341 {
342 	return got_object_id_hex(&blob->id, buf, size);
343 }
344 
345 size_t
346 got_object_blob_get_hdrlen(struct got_blob_object *blob)
347 {
348 	return blob->hdrlen;
349 }
350 
351 const uint8_t *
352 got_object_blob_get_read_buf(struct got_blob_object *blob)
353 {
354 	return blob->read_buf;
355 }
356 
357 const struct got_error *
358 got_object_blob_read_block(size_t *outlenp, struct got_blob_object *blob)
359 {
360 	size_t n;
361 
362 	n = fread(blob->read_buf, 1, blob->blocksize, blob->f);
363 	if (n == 0 && ferror(blob->f))
364 		return got_ferror(blob->f, GOT_ERR_IO);
365 	*outlenp = n;
366 	return NULL;
367 }
368 
369 const struct got_error *
370 got_object_blob_is_binary(int *binary, struct got_blob_object *blob)
371 {
372 	const struct got_error *err;
373 	size_t hdrlen, len;
374 
375 	*binary = 0;
376 	hdrlen = got_object_blob_get_hdrlen(blob);
377 
378 	if (fseeko(blob->f, hdrlen, SEEK_SET) == -1)
379 		return got_error_from_errno("fseeko");
380 
381 	err = got_object_blob_read_block(&len, blob);
382 	if (err)
383 		return err;
384 
385 	*binary = memchr(blob->read_buf, '\0', len) != NULL;
386 
387 	if (fseeko(blob->f, hdrlen, SEEK_SET) == -1)
388 		return got_error_from_errno("fseeko");
389 	return NULL;
390 }
391 
392 const struct got_error *
393 got_object_blob_getline(char **line, ssize_t *linelen, size_t *linesize,
394     struct got_blob_object *blob)
395 {
396 	*linelen = getline(line, linesize, blob->f);
397 	if (*linelen == -1 && !feof(blob->f))
398 		return got_error_from_errno("getline");
399 	return NULL;
400 }
401 
402 const struct got_error *
403 got_object_blob_dump_to_file(off_t *filesize, int *nlines,
404     off_t **line_offsets, FILE *outfile, struct got_blob_object *blob)
405 {
406 	const struct got_error *err = NULL;
407 	size_t n, len, hdrlen;
408 	const uint8_t *buf;
409 	int i;
410 	const int alloc_chunksz = 512;
411 	size_t nalloc = 0;
412 	off_t off = 0, total_len = 0;
413 
414 	if (line_offsets)
415 		*line_offsets = NULL;
416 	if (filesize)
417 		*filesize = 0;
418 	if (nlines)
419 		*nlines = 0;
420 
421 	hdrlen = got_object_blob_get_hdrlen(blob);
422 	do {
423 		err = got_object_blob_read_block(&len, blob);
424 		if (err)
425 			return err;
426 		if (len == 0)
427 			break;
428 		buf = got_object_blob_get_read_buf(blob);
429 		i = hdrlen;
430 		if (nlines) {
431 			if (line_offsets && *line_offsets == NULL) {
432 				/* Have some data but perhaps no '\n'. */
433 				*nlines = 1;
434 				nalloc = alloc_chunksz;
435 				*line_offsets = calloc(nalloc,
436 				    sizeof(**line_offsets));
437 				if (*line_offsets == NULL)
438 					return got_error_from_errno("calloc");
439 
440 				/* Skip forward over end of first line. */
441 				while (i < len) {
442 					if (buf[i] == '\n')
443 						break;
444 					i++;
445 				}
446 			}
447 			/* Scan '\n' offsets in remaining chunk of data. */
448 			while (i < len) {
449 				if (buf[i] != '\n') {
450 					i++;
451 					continue;
452 				}
453 				(*nlines)++;
454 				if (line_offsets && nalloc < *nlines) {
455 					size_t n = *nlines + alloc_chunksz;
456 					off_t *o = recallocarray(*line_offsets,
457 					    nalloc, n, sizeof(**line_offsets));
458 					if (o == NULL) {
459 						free(*line_offsets);
460 						*line_offsets = NULL;
461 						return got_error_from_errno(
462 						    "recallocarray");
463 					}
464 					*line_offsets = o;
465 					nalloc = n;
466 				}
467 				if (line_offsets) {
468 					off = total_len + i - hdrlen + 1;
469 					(*line_offsets)[*nlines - 1] = off;
470 				}
471 				i++;
472 			}
473 		}
474 		/* Skip blob object header first time around. */
475 		n = fwrite(buf + hdrlen, 1, len - hdrlen, outfile);
476 		if (n != len - hdrlen)
477 			return got_ferror(outfile, GOT_ERR_IO);
478 		total_len += len - hdrlen;
479 		hdrlen = 0;
480 	} while (len != 0);
481 
482 	if (fflush(outfile) != 0)
483 		return got_error_from_errno("fflush");
484 	rewind(outfile);
485 
486 	if (filesize)
487 		*filesize = total_len;
488 
489 	return NULL;
490 }
491 
492 const char *
493 got_object_tag_get_name(struct got_tag_object *tag)
494 {
495 	return tag->tag;
496 }
497 
498 int
499 got_object_tag_get_object_type(struct got_tag_object *tag)
500 {
501 	return tag->obj_type;
502 }
503 
504 struct got_object_id *
505 got_object_tag_get_object_id(struct got_tag_object *tag)
506 {
507 	return &tag->id;
508 }
509 
510 time_t
511 got_object_tag_get_tagger_time(struct got_tag_object *tag)
512 {
513 	return tag->tagger_time;
514 }
515 
516 time_t
517 got_object_tag_get_tagger_gmtoff(struct got_tag_object *tag)
518 {
519 	return tag->tagger_gmtoff;
520 }
521 
522 const char *
523 got_object_tag_get_tagger(struct got_tag_object *tag)
524 {
525 	return tag->tagger;
526 }
527 
528 const char *
529 got_object_tag_get_message(struct got_tag_object *tag)
530 {
531 	return tag->tagmsg;
532 }
533 
534 static struct got_tree_entry *
535 find_entry_by_name(struct got_tree_object *tree, const char *name, size_t len)
536 {
537 	int i;
538 
539 	/* Note that tree entries are sorted in strncmp() order. */
540 	for (i = 0; i < tree->nentries; i++) {
541 		struct got_tree_entry *te = &tree->entries[i];
542 		int cmp = strncmp(te->name, name, len);
543 		if (cmp < 0)
544 			continue;
545 		if (cmp > 0)
546 			break;
547 		if (te->name[len] == '\0')
548 			return te;
549 	}
550 	return NULL;
551 }
552 
553 struct got_tree_entry *
554 got_object_tree_find_entry(struct got_tree_object *tree, const char *name)
555 {
556 	return find_entry_by_name(tree, name, strlen(name));
557 }
558 
559 const struct got_error *
560 got_object_tree_find_path(struct got_object_id **id, mode_t *mode,
561     struct got_repository *repo, struct got_tree_object *tree,
562     const char *path)
563 {
564 	const struct got_error *err = NULL;
565 	struct got_tree_object *subtree = NULL;
566 	struct got_tree_entry *te = NULL;
567 	const char *seg, *s;
568 	size_t seglen;
569 
570 	*id = NULL;
571 
572 	s = path;
573 	while (s[0] == '/')
574 		s++;
575 	seg = s;
576 	seglen = 0;
577 	subtree = tree;
578 	while (*s) {
579 		struct got_tree_object *next_tree;
580 
581 		if (*s != '/') {
582 			s++;
583 			seglen++;
584 			if (*s)
585 				continue;
586 		}
587 
588 		te = find_entry_by_name(subtree, seg, seglen);
589 		if (te == NULL) {
590 			err = got_error_path(path, GOT_ERR_NO_TREE_ENTRY);
591 			goto done;
592 		}
593 
594 		if (*s == '\0')
595 			break;
596 
597 		seg = s + 1;
598 		seglen = 0;
599 		s++;
600 		if (*s) {
601 			err = got_object_open_as_tree(&next_tree, repo,
602 			    &te->id);
603 			te = NULL;
604 			if (err)
605 				goto done;
606 			if (subtree != tree)
607 				got_object_tree_close(subtree);
608 			subtree = next_tree;
609 		}
610 	}
611 
612 	if (te) {
613 		*id = got_object_id_dup(&te->id);
614 		if (*id == NULL)
615 			return got_error_from_errno("got_object_id_dup");
616 		if (mode)
617 			*mode = te->mode;
618 	} else
619 		err = got_error_path(path, GOT_ERR_NO_TREE_ENTRY);
620 done:
621 	if (subtree && subtree != tree)
622 		got_object_tree_close(subtree);
623 	return err;
624 }
625 
626 const struct got_error *
627 got_object_id_by_path(struct got_object_id **id, struct got_repository *repo,
628     struct got_commit_object *commit, const char *path)
629 {
630 	const struct got_error *err = NULL;
631 	struct got_tree_object *tree = NULL;
632 
633 	*id = NULL;
634 
635 	/* Handle opening of root of commit's tree. */
636 	if (got_path_is_root_dir(path)) {
637 		*id = got_object_id_dup(commit->tree_id);
638 		if (*id == NULL)
639 			err = got_error_from_errno("got_object_id_dup");
640 	} else {
641 		err = got_object_open_as_tree(&tree, repo, commit->tree_id);
642 		if (err)
643 			goto done;
644 		err = got_object_tree_find_path(id, NULL, repo, tree, path);
645 	}
646 done:
647 	if (tree)
648 		got_object_tree_close(tree);
649 	return err;
650 }
651 
652 /*
653  * Normalize file mode bits to avoid false positive tree entry differences
654  * in case tree entries have unexpected mode bits set.
655  */
656 static mode_t
657 normalize_mode_for_comparison(mode_t mode)
658 {
659 	/*
660 	 * For directories, the only relevant bit is the IFDIR bit.
661 	 * This allows us to detect paths changing from a directory
662 	 * to a file and vice versa.
663 	 */
664 	if (S_ISDIR(mode))
665 		return mode & S_IFDIR;
666 
667 	/*
668 	 * For symlinks, the only relevant bit is the IFLNK bit.
669 	 * This allows us to detect paths changing from a symlinks
670 	 * to a file or directory and vice versa.
671 	 */
672 	if (S_ISLNK(mode))
673 		return mode & S_IFLNK;
674 
675 	/* For files, the only change we care about is the executable bit. */
676 	return mode & S_IXUSR;
677 }
678 
679 const struct got_error *
680 got_object_tree_path_changed(int *changed,
681     struct got_tree_object *tree01, struct got_tree_object *tree02,
682     const char *path, struct got_repository *repo)
683 {
684 	const struct got_error *err = NULL;
685 	struct got_tree_object *tree1 = NULL, *tree2 = NULL;
686 	struct got_tree_entry *te1 = NULL, *te2 = NULL;
687 	const char *seg, *s;
688 	size_t seglen;
689 
690 	*changed = 0;
691 
692 	/* We not do support comparing the root path. */
693 	if (got_path_is_root_dir(path))
694 		return got_error_path(path, GOT_ERR_BAD_PATH);
695 
696 	tree1 = tree01;
697 	tree2 = tree02;
698 	s = path;
699 	while (*s == '/')
700 		s++;
701 	seg = s;
702 	seglen = 0;
703 	while (*s) {
704 		struct got_tree_object *next_tree1, *next_tree2;
705 		mode_t mode1, mode2;
706 
707 		if (*s != '/') {
708 			s++;
709 			seglen++;
710 			if (*s)
711 				continue;
712 		}
713 
714 		te1 = find_entry_by_name(tree1, seg, seglen);
715 		if (te1 == NULL) {
716 			err = got_error(GOT_ERR_NO_OBJ);
717 			goto done;
718 		}
719 
720 		if (tree2)
721 			te2 = find_entry_by_name(tree2, seg, seglen);
722 
723 		if (te2) {
724 			mode1 = normalize_mode_for_comparison(te1->mode);
725 			mode2 = normalize_mode_for_comparison(te2->mode);
726 			if (mode1 != mode2) {
727 				*changed = 1;
728 				goto done;
729 			}
730 
731 			if (got_object_id_cmp(&te1->id, &te2->id) == 0) {
732 				*changed = 0;
733 				goto done;
734 			}
735 		}
736 
737 		if (*s == '\0') { /* final path element */
738 			*changed = 1;
739 			goto done;
740 		}
741 
742 		seg = s + 1;
743 		s++;
744 		seglen = 0;
745 		if (*s) {
746 			err = got_object_open_as_tree(&next_tree1, repo,
747 			    &te1->id);
748 			te1 = NULL;
749 			if (err)
750 				goto done;
751 			if (tree1 != tree01)
752 				got_object_tree_close(tree1);
753 			tree1 = next_tree1;
754 
755 			if (te2) {
756 				err = got_object_open_as_tree(&next_tree2, repo,
757 				    &te2->id);
758 				te2 = NULL;
759 				if (err)
760 					goto done;
761 				if (tree2 != tree02)
762 					got_object_tree_close(tree2);
763 				tree2 = next_tree2;
764 			} else if (tree2) {
765 				if (tree2 != tree02)
766 					got_object_tree_close(tree2);
767 				tree2 = NULL;
768 			}
769 		}
770 	}
771 done:
772 	if (tree1 && tree1 != tree01)
773 		got_object_tree_close(tree1);
774 	if (tree2 && tree2 != tree02)
775 		got_object_tree_close(tree2);
776 	return err;
777 }
778 
779 const struct got_error *
780 got_object_tree_entry_dup(struct got_tree_entry **new_te,
781     struct got_tree_entry *te)
782 {
783 	const struct got_error *err = NULL;
784 
785 	*new_te = calloc(1, sizeof(**new_te));
786 	if (*new_te == NULL)
787 		return got_error_from_errno("calloc");
788 
789 	(*new_te)->mode = te->mode;
790 	memcpy((*new_te)->name, te->name, sizeof((*new_te)->name));
791 	memcpy(&(*new_te)->id, &te->id, sizeof((*new_te)->id));
792 	return err;
793 }
794 
795 int
796 got_object_tree_entry_is_submodule(struct got_tree_entry *te)
797 {
798 	return (te->mode & S_IFMT) == (S_IFDIR | S_IFLNK);
799 }
800 
801 int
802 got_object_tree_entry_is_symlink(struct got_tree_entry *te)
803 {
804 	/* S_IFDIR check avoids confusing symlinks with submodules. */
805 	return ((te->mode & (S_IFDIR | S_IFLNK)) == S_IFLNK);
806 }
807 
808 static const struct got_error *
809 resolve_symlink(char **link_target, const char *path,
810     struct got_commit_object *commit, struct got_repository *repo)
811 {
812 	const struct got_error *err = NULL;
813 	char buf[PATH_MAX];
814 	char *name, *parent_path = NULL;
815 	struct got_object_id *tree_obj_id = NULL;
816 	struct got_tree_object *tree = NULL;
817 	struct got_tree_entry *te = NULL;
818 
819 	*link_target = NULL;
820 
821 	if (strlcpy(buf, path, sizeof(buf)) >= sizeof(buf))
822 		return got_error(GOT_ERR_NO_SPACE);
823 
824 	name = basename(buf);
825 	if (name == NULL)
826 		return got_error_from_errno2("basename", path);
827 
828 	err = got_path_dirname(&parent_path, path);
829 	if (err)
830 		return err;
831 
832 	err = got_object_id_by_path(&tree_obj_id, repo, commit,
833 	    parent_path);
834 	if (err) {
835 		if (err->code == GOT_ERR_NO_TREE_ENTRY) {
836 			/* Display the complete path in error message. */
837 			err = got_error_path(path, err->code);
838 		}
839 		goto done;
840 	}
841 
842 	err = got_object_open_as_tree(&tree, repo, tree_obj_id);
843 	if (err)
844 		goto done;
845 
846 	te = got_object_tree_find_entry(tree, name);
847 	if (te == NULL) {
848 		err = got_error_path(path, GOT_ERR_NO_TREE_ENTRY);
849 		goto done;
850 	}
851 
852 	if (got_object_tree_entry_is_symlink(te)) {
853 		err = got_tree_entry_get_symlink_target(link_target, te, repo);
854 		if (err)
855 			goto done;
856 		if (!got_path_is_absolute(*link_target)) {
857 			char *abspath;
858 			if (asprintf(&abspath, "%s/%s", parent_path,
859 			    *link_target) == -1) {
860 				err = got_error_from_errno("asprintf");
861 				goto done;
862 			}
863 			free(*link_target);
864 			*link_target = malloc(PATH_MAX);
865 			if (*link_target == NULL) {
866 				err = got_error_from_errno("malloc");
867 				goto done;
868 			}
869 			err = got_canonpath(abspath, *link_target, PATH_MAX);
870 			free(abspath);
871 			if (err)
872 				goto done;
873 		}
874 	}
875 done:
876 	free(parent_path);
877 	free(tree_obj_id);
878 	if (tree)
879 		got_object_tree_close(tree);
880 	if (err) {
881 		free(*link_target);
882 		*link_target = NULL;
883 	}
884 	return err;
885 }
886 
887 const struct got_error *
888 got_object_resolve_symlinks(char **link_target, const char *path,
889     struct got_commit_object *commit, struct got_repository *repo)
890 {
891 	const struct got_error *err = NULL;
892 	char *next_target = NULL;
893 	int max_recursion = 40; /* matches Git */
894 
895 	*link_target = NULL;
896 
897 	do {
898 		err = resolve_symlink(&next_target,
899 		    *link_target ? *link_target : path, commit, repo);
900 		if (err)
901 			break;
902 		if (next_target) {
903 			free(*link_target);
904 			if (--max_recursion == 0) {
905 				err = got_error_path(path, GOT_ERR_RECURSION);
906 				*link_target = NULL;
907 				break;
908 			}
909 			*link_target = next_target;
910 		}
911 	} while (next_target);
912 
913 	return err;
914 }
915 
916 void
917 got_object_commit_retain(struct got_commit_object *commit)
918 {
919 	commit->refcnt++;
920 }
921 
922 const struct got_error *
923 got_object_raw_alloc(struct got_raw_object **obj, uint8_t *outbuf, int *outfd,
924     size_t max_in_mem_size, size_t hdrlen, off_t size)
925 {
926 	const struct got_error *err = NULL;
927 	off_t tot;
928 
929 	tot = hdrlen + size;
930 
931 	*obj = calloc(1, sizeof(**obj));
932 	if (*obj == NULL) {
933 		err = got_error_from_errno("calloc");
934 		goto done;
935 	}
936 	(*obj)->fd = -1;
937 	(*obj)->tempfile_idx = -1;
938 
939 	if (outbuf) {
940 		(*obj)->data = outbuf;
941 	} else {
942 		struct stat sb;
943 		if (fstat(*outfd, &sb) == -1) {
944 			err = got_error_from_errno("fstat");
945 			goto done;
946 		}
947 
948 		if (sb.st_size != tot) {
949 			err = got_error_msg(GOT_ERR_BAD_OBJ_HDR,
950 			    "raw object has unexpected size");
951 			goto done;
952 		}
953 #ifndef GOT_PACK_NO_MMAP
954 		if (tot > 0 && tot <= max_in_mem_size) {
955 			(*obj)->data = mmap(NULL, tot, PROT_READ,
956 			    MAP_PRIVATE, *outfd, 0);
957 			if ((*obj)->data == MAP_FAILED) {
958 				if (errno != ENOMEM) {
959 					err = got_error_from_errno("mmap");
960 					goto done;
961 				}
962 				(*obj)->data = NULL;
963 			} else {
964 				(*obj)->fd = *outfd;
965 				*outfd = -1;
966 			}
967 		}
968 #endif
969 		if (*outfd != -1) {
970 			(*obj)->f = fdopen(*outfd, "r");
971 			if ((*obj)->f == NULL) {
972 				err = got_error_from_errno("fdopen");
973 				goto done;
974 			}
975 			*outfd = -1;
976 		}
977 	}
978 	(*obj)->hdrlen = hdrlen;
979 	(*obj)->size = size;
980 done:
981 	if (err) {
982 		if (*obj) {
983 			got_object_raw_close(*obj);
984 			*obj = NULL;
985 		}
986 	} else
987 		(*obj)->refcnt++;
988 	return err;
989 }