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Date:: Tue Oct 25 07:37:58 2022 UTC
Message:: check size before calling mmap(2) It's only a preparatory step, as checking whether a size_t is less than SIZE_MAX is moot. In a follow-up commit, however, the `filesize' field of the struct got_pack will become off_t and these checks will kick in. This also makes consistent how we guard mmap(2) against empty files. ok and improvements stsp@
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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/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_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_sha1_digest(id.sha1, id_str))
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 const struct got_error *
179 got_object_qid_alloc(struct got_object_qid **qid, struct got_object_id *id)
180 {
181 	*qid = calloc(1, sizeof(**qid));
182 	if (*qid == NULL)
183 		return got_error_from_errno("calloc");
184 
185 	memcpy(&(*qid)->id, id, sizeof((*qid)->id));
186 	return NULL;
187 }
188 
189 const struct got_error *
190 got_object_id_queue_copy(const struct got_object_id_queue *src,
191     struct got_object_id_queue *dest)
192 {
193 	const struct got_error *err;
194 	struct got_object_qid *qid;
195 
196 	STAILQ_FOREACH(qid, src, entry) {
197 		struct got_object_qid *new;
198 		/*
199 		 * Deep-copy the object ID only. Let the caller deal
200 		 * with setting up the new->data pointer if needed.
201 		 */
202 		err = got_object_qid_alloc(&new, &qid->id);
203 		if (err) {
204 			got_object_id_queue_free(dest);
205 			return err;
206 		}
207 		STAILQ_INSERT_TAIL(dest, new, entry);
208 	}
209 
210 	return NULL;
211 }
212 
213 int
214 got_object_tree_get_nentries(struct got_tree_object *tree)
215 {
216 	return tree->nentries;
217 }
218 
219 struct got_tree_entry *
220 got_object_tree_get_first_entry(struct got_tree_object *tree)
221 {
222 	return got_object_tree_get_entry(tree, 0);
223 }
224 
225 struct got_tree_entry *
226 got_object_tree_get_last_entry(struct got_tree_object *tree)
227 {
228 	return got_object_tree_get_entry(tree, tree->nentries - 1);
229 }
230 
231 struct got_tree_entry *
232 got_object_tree_get_entry(struct got_tree_object *tree, int i)
233 {
234 	if (i < 0 || i >= tree->nentries)
235 		return NULL;
236 	return &tree->entries[i];
237 }
238 
239 mode_t
240 got_tree_entry_get_mode(struct got_tree_entry *te)
241 {
242 	return te->mode;
243 }
244 
245 const char *
246 got_tree_entry_get_name(struct got_tree_entry *te)
247 {
248 	return &te->name[0];
249 }
250 
251 struct got_object_id *
252 got_tree_entry_get_id(struct got_tree_entry *te)
253 {
254 	return &te->id;
255 }
256 
257 const struct got_error *
258 got_object_blob_read_to_str(char **s, struct got_blob_object *blob)
259 {
260 	const struct got_error *err = NULL;
261 	size_t len, totlen, hdrlen, offset;
262 
263 	*s = NULL;
264 
265 	hdrlen = got_object_blob_get_hdrlen(blob);
266 	totlen = 0;
267 	offset = 0;
268 	do {
269 		char *p;
270 
271 		err = got_object_blob_read_block(&len, blob);
272 		if (err)
273 			return err;
274 
275 		if (len == 0)
276 			break;
277 
278 		totlen += len - hdrlen;
279 		p = realloc(*s, totlen + 1);
280 		if (p == NULL) {
281 			err = got_error_from_errno("realloc");
282 			free(*s);
283 			*s = NULL;
284 			return err;
285 		}
286 		*s = p;
287 		/* Skip blob object header first time around. */
288 		memcpy(*s + offset,
289 		    got_object_blob_get_read_buf(blob) + hdrlen, len - hdrlen);
290 		hdrlen = 0;
291 		offset = totlen;
292 	} while (len > 0);
293 
294 	(*s)[totlen] = '\0';
295 	return NULL;
296 }
297 
298 const struct got_error *
299 got_tree_entry_get_symlink_target(char **link_target, struct got_tree_entry *te,
300     struct got_repository *repo)
301 {
302 	const struct got_error *err = NULL;
303 	struct got_blob_object *blob = NULL;
304 	int fd = -1;
305 
306 	*link_target = NULL;
307 
308 	if (!got_object_tree_entry_is_symlink(te))
309 		return got_error(GOT_ERR_TREE_ENTRY_TYPE);
310 
311 	fd = got_opentempfd();
312 	if (fd == -1) {
313 		err = got_error_from_errno("got_opentempfd");
314 		goto done;
315 	}
316 
317 	err = got_object_open_as_blob(&blob, repo,
318 	    got_tree_entry_get_id(te), PATH_MAX, fd);
319 	if (err)
320 		goto done;
321 
322 	err = got_object_blob_read_to_str(link_target, blob);
323 done:
324 	if (fd != -1 && close(fd) == -1 && err == NULL)
325 		err = got_error_from_errno("close");
326 	if (blob)
327 		got_object_blob_close(blob);
328 	if (err) {
329 		free(*link_target);
330 		*link_target = NULL;
331 	}
332 	return err;
333 }
334 
335 int
336 got_tree_entry_get_index(struct got_tree_entry *te)
337 {
338 	return te->idx;
339 }
340 
341 struct got_tree_entry *
342 got_tree_entry_get_next(struct got_tree_object *tree,
343     struct got_tree_entry *te)
344 {
345 	return got_object_tree_get_entry(tree, te->idx + 1);
346 }
347 
348 struct got_tree_entry *
349 got_tree_entry_get_prev(struct got_tree_object *tree,
350     struct got_tree_entry *te)
351 {
352 	return got_object_tree_get_entry(tree, te->idx - 1);
353 }
354 
355 const struct got_error *
356 got_object_blob_close(struct got_blob_object *blob)
357 {
358 	const struct got_error *err = NULL;
359 	free(blob->read_buf);
360 	if (blob->f && fclose(blob->f) == EOF)
361 		err = got_error_from_errno("fclose");
362 	free(blob->data);
363 	free(blob);
364 	return err;
365 }
366 
367 void
368 got_object_blob_rewind(struct got_blob_object *blob)
369 {
370 	if (blob->f)
371 		rewind(blob->f);
372 }
373 
374 char *
375 got_object_blob_id_str(struct got_blob_object *blob, char *buf, size_t size)
376 {
377 	return got_sha1_digest_to_str(blob->id.sha1, buf, size);
378 }
379 
380 size_t
381 got_object_blob_get_hdrlen(struct got_blob_object *blob)
382 {
383 	return blob->hdrlen;
384 }
385 
386 const uint8_t *
387 got_object_blob_get_read_buf(struct got_blob_object *blob)
388 {
389 	return blob->read_buf;
390 }
391 
392 const struct got_error *
393 got_object_blob_read_block(size_t *outlenp, struct got_blob_object *blob)
394 {
395 	size_t n;
396 
397 	n = fread(blob->read_buf, 1, blob->blocksize, blob->f);
398 	if (n == 0 && ferror(blob->f))
399 		return got_ferror(blob->f, GOT_ERR_IO);
400 	*outlenp = n;
401 	return NULL;
402 }
403 
404 const struct got_error *
405 got_object_blob_dump_to_file(off_t *filesize, int *nlines,
406     off_t **line_offsets, FILE *outfile, struct got_blob_object *blob)
407 {
408 	const struct got_error *err = NULL;
409 	size_t n, len, hdrlen;
410 	const uint8_t *buf;
411 	int i;
412 	const int alloc_chunksz = 512;
413 	size_t nalloc = 0;
414 	off_t off = 0, total_len = 0;
415 
416 	if (line_offsets)
417 		*line_offsets = NULL;
418 	if (filesize)
419 		*filesize = 0;
420 	if (nlines)
421 		*nlines = 0;
422 
423 	hdrlen = got_object_blob_get_hdrlen(blob);
424 	do {
425 		err = got_object_blob_read_block(&len, blob);
426 		if (err)
427 			return err;
428 		if (len == 0)
429 			break;
430 		buf = got_object_blob_get_read_buf(blob);
431 		i = hdrlen;
432 		if (nlines) {
433 			if (line_offsets && *line_offsets == NULL) {
434 				/* Have some data but perhaps no '\n'. */
435 				*nlines = 1;
436 				nalloc = alloc_chunksz;
437 				*line_offsets = calloc(nalloc,
438 				    sizeof(**line_offsets));
439 				if (*line_offsets == NULL)
440 					return got_error_from_errno("calloc");
441 
442 				/* Skip forward over end of first line. */
443 				while (i < len) {
444 					if (buf[i] == '\n')
445 						break;
446 					i++;
447 				}
448 			}
449 			/* Scan '\n' offsets in remaining chunk of data. */
450 			while (i < len) {
451 				if (buf[i] != '\n') {
452 					i++;
453 					continue;
454 				}
455 				(*nlines)++;
456 				if (line_offsets && nalloc < *nlines) {
457 					size_t n = *nlines + alloc_chunksz;
458 					off_t *o = recallocarray(*line_offsets,
459 					    nalloc, n, sizeof(**line_offsets));
460 					if (o == NULL) {
461 						free(*line_offsets);
462 						*line_offsets = NULL;
463 						return got_error_from_errno(
464 						    "recallocarray");
465 					}
466 					*line_offsets = o;
467 					nalloc = n;
468 				}
469 				if (line_offsets) {
470 					off = total_len + i - hdrlen + 1;
471 					(*line_offsets)[*nlines - 1] = off;
472 				}
473 				i++;
474 			}
475 		}
476 		/* Skip blob object header first time around. */
477 		n = fwrite(buf + hdrlen, 1, len - hdrlen, outfile);
478 		if (n != len - hdrlen)
479 			return got_ferror(outfile, GOT_ERR_IO);
480 		total_len += len - hdrlen;
481 		hdrlen = 0;
482 	} while (len != 0);
483 
484 	if (fflush(outfile) != 0)
485 		return got_error_from_errno("fflush");
486 	rewind(outfile);
487 
488 	if (filesize)
489 		*filesize = total_len;
490 
491 	return NULL;
492 }
493 
494 const char *
495 got_object_tag_get_name(struct got_tag_object *tag)
496 {
497 	return tag->tag;
498 }
499 
500 int
501 got_object_tag_get_object_type(struct got_tag_object *tag)
502 {
503 	return tag->obj_type;
504 }
505 
506 struct got_object_id *
507 got_object_tag_get_object_id(struct got_tag_object *tag)
508 {
509 	return &tag->id;
510 }
511 
512 time_t
513 got_object_tag_get_tagger_time(struct got_tag_object *tag)
514 {
515 	return tag->tagger_time;
516 }
517 
518 time_t
519 got_object_tag_get_tagger_gmtoff(struct got_tag_object *tag)
520 {
521 	return tag->tagger_gmtoff;
522 }
523 
524 const char *
525 got_object_tag_get_tagger(struct got_tag_object *tag)
526 {
527 	return tag->tagger;
528 }
529 
530 const char *
531 got_object_tag_get_message(struct got_tag_object *tag)
532 {
533 	return tag->tagmsg;
534 }
535 
536 static struct got_tree_entry *
537 find_entry_by_name(struct got_tree_object *tree, const char *name, size_t len)
538 {
539 	int i;
540 
541 	/* Note that tree entries are sorted in strncmp() order. */
542 	for (i = 0; i < tree->nentries; i++) {
543 		struct got_tree_entry *te = &tree->entries[i];
544 		int cmp = strncmp(te->name, name, len);
545 		if (cmp < 0)
546 			continue;
547 		if (cmp > 0)
548 			break;
549 		if (te->name[len] == '\0')
550 			return te;
551 	}
552 	return NULL;
553 }
554 
555 struct got_tree_entry *
556 got_object_tree_find_entry(struct got_tree_object *tree, const char *name)
557 {
558 	return find_entry_by_name(tree, name, strlen(name));
559 }
560 
561 const struct got_error *
562 got_object_tree_find_path(struct got_object_id **id, mode_t *mode,
563     struct got_repository *repo, struct got_tree_object *tree,
564     const char *path)
565 {
566 	const struct got_error *err = NULL;
567 	struct got_tree_object *subtree = NULL;
568 	struct got_tree_entry *te = NULL;
569 	const char *seg, *s;
570 	size_t seglen;
571 
572 	*id = NULL;
573 
574 	s = path;
575 	while (s[0] == '/')
576 		s++;
577 	seg = s;
578 	seglen = 0;
579 	subtree = tree;
580 	while (*s) {
581 		struct got_tree_object *next_tree;
582 
583 		if (*s != '/') {
584 			s++;
585 			seglen++;
586 			if (*s)
587 				continue;
588 		}
589 
590 		te = find_entry_by_name(subtree, seg, seglen);
591 		if (te == NULL) {
592 			err = got_error_path(path, GOT_ERR_NO_TREE_ENTRY);
593 			goto done;
594 		}
595 
596 		if (*s == '\0')
597 			break;
598 
599 		seg = s + 1;
600 		seglen = 0;
601 		s++;
602 		if (*s) {
603 			err = got_object_open_as_tree(&next_tree, repo,
604 			    &te->id);
605 			te = NULL;
606 			if (err)
607 				goto done;
608 			if (subtree != tree)
609 				got_object_tree_close(subtree);
610 			subtree = next_tree;
611 		}
612 	}
613 
614 	if (te) {
615 		*id = got_object_id_dup(&te->id);
616 		if (*id == NULL)
617 			return got_error_from_errno("got_object_id_dup");
618 		if (mode)
619 			*mode = te->mode;
620 	} else
621 		err = got_error_path(path, GOT_ERR_NO_TREE_ENTRY);
622 done:
623 	if (subtree && subtree != tree)
624 		got_object_tree_close(subtree);
625 	return err;
626 }
627 
628 const struct got_error *
629 got_object_id_by_path(struct got_object_id **id, struct got_repository *repo,
630     struct got_commit_object *commit, const char *path)
631 {
632 	const struct got_error *err = NULL;
633 	struct got_tree_object *tree = NULL;
634 
635 	*id = NULL;
636 
637 	/* Handle opening of root of commit's tree. */
638 	if (got_path_is_root_dir(path)) {
639 		*id = got_object_id_dup(commit->tree_id);
640 		if (*id == NULL)
641 			err = got_error_from_errno("got_object_id_dup");
642 	} else {
643 		err = got_object_open_as_tree(&tree, repo, commit->tree_id);
644 		if (err)
645 			goto done;
646 		err = got_object_tree_find_path(id, NULL, repo, tree, path);
647 	}
648 done:
649 	if (tree)
650 		got_object_tree_close(tree);
651 	return err;
652 }
653 
654 /*
655  * Normalize file mode bits to avoid false positive tree entry differences
656  * in case tree entries have unexpected mode bits set.
657  */
658 static mode_t
659 normalize_mode_for_comparison(mode_t mode)
660 {
661 	/*
662 	 * For directories, the only relevant bit is the IFDIR bit.
663 	 * This allows us to detect paths changing from a directory
664 	 * to a file and vice versa.
665 	 */
666 	if (S_ISDIR(mode))
667 		return mode & S_IFDIR;
668 
669 	/*
670 	 * For symlinks, the only relevant bit is the IFLNK bit.
671 	 * This allows us to detect paths changing from a symlinks
672 	 * to a file or directory and vice versa.
673 	 */
674 	if (S_ISLNK(mode))
675 		return mode & S_IFLNK;
676 
677 	/* For files, the only change we care about is the executable bit. */
678 	return mode & S_IXUSR;
679 }
680 
681 const struct got_error *
682 got_object_tree_path_changed(int *changed,
683     struct got_tree_object *tree01, struct got_tree_object *tree02,
684     const char *path, struct got_repository *repo)
685 {
686 	const struct got_error *err = NULL;
687 	struct got_tree_object *tree1 = NULL, *tree2 = NULL;
688 	struct got_tree_entry *te1 = NULL, *te2 = NULL;
689 	const char *seg, *s;
690 	size_t seglen;
691 
692 	*changed = 0;
693 
694 	/* We not do support comparing the root path. */
695 	if (got_path_is_root_dir(path))
696 		return got_error_path(path, GOT_ERR_BAD_PATH);
697 
698 	tree1 = tree01;
699 	tree2 = tree02;
700 	s = path;
701 	while (*s == '/')
702 		s++;
703 	seg = s;
704 	seglen = 0;
705 	while (*s) {
706 		struct got_tree_object *next_tree1, *next_tree2;
707 		mode_t mode1, mode2;
708 
709 		if (*s != '/') {
710 			s++;
711 			seglen++;
712 			if (*s)
713 				continue;
714 		}
715 
716 		te1 = find_entry_by_name(tree1, seg, seglen);
717 		if (te1 == NULL) {
718 			err = got_error(GOT_ERR_NO_OBJ);
719 			goto done;
720 		}
721 
722 		if (tree2)
723 			te2 = find_entry_by_name(tree2, seg, seglen);
724 
725 		if (te2) {
726 			mode1 = normalize_mode_for_comparison(te1->mode);
727 			mode2 = normalize_mode_for_comparison(te2->mode);
728 			if (mode1 != mode2) {
729 				*changed = 1;
730 				goto done;
731 			}
732 
733 			if (got_object_id_cmp(&te1->id, &te2->id) == 0) {
734 				*changed = 0;
735 				goto done;
736 			}
737 		}
738 
739 		if (*s == '\0') { /* final path element */
740 			*changed = 1;
741 			goto done;
742 		}
743 
744 		seg = s + 1;
745 		s++;
746 		seglen = 0;
747 		if (*s) {
748 			err = got_object_open_as_tree(&next_tree1, repo,
749 			    &te1->id);
750 			te1 = NULL;
751 			if (err)
752 				goto done;
753 			if (tree1 != tree01)
754 				got_object_tree_close(tree1);
755 			tree1 = next_tree1;
756 
757 			if (te2) {
758 				err = got_object_open_as_tree(&next_tree2, repo,
759 				    &te2->id);
760 				te2 = NULL;
761 				if (err)
762 					goto done;
763 				if (tree2 != tree02)
764 					got_object_tree_close(tree2);
765 				tree2 = next_tree2;
766 			} else if (tree2) {
767 				if (tree2 != tree02)
768 					got_object_tree_close(tree2);
769 				tree2 = NULL;
770 			}
771 		}
772 	}
773 done:
774 	if (tree1 && tree1 != tree01)
775 		got_object_tree_close(tree1);
776 	if (tree2 && tree2 != tree02)
777 		got_object_tree_close(tree2);
778 	return err;
779 }
780 
781 const struct got_error *
782 got_object_tree_entry_dup(struct got_tree_entry **new_te,
783     struct got_tree_entry *te)
784 {
785 	const struct got_error *err = NULL;
786 
787 	*new_te = calloc(1, sizeof(**new_te));
788 	if (*new_te == NULL)
789 		return got_error_from_errno("calloc");
790 
791 	(*new_te)->mode = te->mode;
792 	memcpy((*new_te)->name, te->name, sizeof((*new_te)->name));
793 	memcpy(&(*new_te)->id, &te->id, sizeof((*new_te)->id));
794 	return err;
795 }
796 
797 int
798 got_object_tree_entry_is_submodule(struct got_tree_entry *te)
799 {
800 	return (te->mode & S_IFMT) == (S_IFDIR | S_IFLNK);
801 }
802 
803 int
804 got_object_tree_entry_is_symlink(struct got_tree_entry *te)
805 {
806 	/* S_IFDIR check avoids confusing symlinks with submodules. */
807 	return ((te->mode & (S_IFDIR | S_IFLNK)) == S_IFLNK);
808 }
809 
810 static const struct got_error *
811 resolve_symlink(char **link_target, const char *path,
812     struct got_commit_object *commit, struct got_repository *repo)
813 {
814 	const struct got_error *err = NULL;
815 	char buf[PATH_MAX];
816 	char *name, *parent_path = NULL;
817 	struct got_object_id *tree_obj_id = NULL;
818 	struct got_tree_object *tree = NULL;
819 	struct got_tree_entry *te = NULL;
820 
821 	*link_target = NULL;
822 
823 	if (strlcpy(buf, path, sizeof(buf)) >= sizeof(buf))
824 		return got_error(GOT_ERR_NO_SPACE);
825 
826 	name = basename(buf);
827 	if (name == NULL)
828 		return got_error_from_errno2("basename", path);
829 
830 	err = got_path_dirname(&parent_path, path);
831 	if (err)
832 		return err;
833 
834 	err = got_object_id_by_path(&tree_obj_id, repo, commit,
835 	    parent_path);
836 	if (err) {
837 		if (err->code == GOT_ERR_NO_TREE_ENTRY) {
838 			/* Display the complete path in error message. */
839 			err = got_error_path(path, err->code);
840 		}
841 		goto done;
842 	}
843 
844 	err = got_object_open_as_tree(&tree, repo, tree_obj_id);
845 	if (err)
846 		goto done;
847 
848 	te = got_object_tree_find_entry(tree, name);
849 	if (te == NULL) {
850 		err = got_error_path(path, GOT_ERR_NO_TREE_ENTRY);
851 		goto done;
852 	}
853 
854 	if (got_object_tree_entry_is_symlink(te)) {
855 		err = got_tree_entry_get_symlink_target(link_target, te, repo);
856 		if (err)
857 			goto done;
858 		if (!got_path_is_absolute(*link_target)) {
859 			char *abspath;
860 			if (asprintf(&abspath, "%s/%s", parent_path,
861 			    *link_target) == -1) {
862 				err = got_error_from_errno("asprintf");
863 				goto done;
864 			}
865 			free(*link_target);
866 			*link_target = malloc(PATH_MAX);
867 			if (*link_target == NULL) {
868 				err = got_error_from_errno("malloc");
869 				goto done;
870 			}
871 			err = got_canonpath(abspath, *link_target, PATH_MAX);
872 			free(abspath);
873 			if (err)
874 				goto done;
875 		}
876 	}
877 done:
878 	free(parent_path);
879 	free(tree_obj_id);
880 	if (tree)
881 		got_object_tree_close(tree);
882 	if (err) {
883 		free(*link_target);
884 		*link_target = NULL;
885 	}
886 	return err;
887 }
888 
889 const struct got_error *
890 got_object_resolve_symlinks(char **link_target, const char *path,
891     struct got_commit_object *commit, struct got_repository *repo)
892 {
893 	const struct got_error *err = NULL;
894 	char *next_target = NULL;
895 	int max_recursion = 40; /* matches Git */
896 
897 	*link_target = NULL;
898 
899 	do {
900 		err = resolve_symlink(&next_target,
901 		    *link_target ? *link_target : path, commit, repo);
902 		if (err)
903 			break;
904 		if (next_target) {
905 			free(*link_target);
906 			if (--max_recursion == 0) {
907 				err = got_error_path(path, GOT_ERR_RECURSION);
908 				*link_target = NULL;
909 				break;
910 			}
911 			*link_target = next_target;
912 		}
913 	} while (next_target);
914 
915 	return err;
916 }
917 
918 void
919 got_object_commit_retain(struct got_commit_object *commit)
920 {
921 	commit->refcnt++;
922 }
923 
924 const struct got_error *
925 got_object_raw_alloc(struct got_raw_object **obj, uint8_t *outbuf, int *outfd,
926     size_t hdrlen, off_t size)
927 {
928 	const struct got_error *err = NULL;
929 	off_t tot;
930 
931 	tot = hdrlen + size;
932 
933 	*obj = calloc(1, sizeof(**obj));
934 	if (*obj == NULL) {
935 		err = got_error_from_errno("calloc");
936 		goto done;
937 	}
938 	(*obj)->fd = -1;
939 	(*obj)->tempfile_idx = -1;
940 
941 	if (outbuf) {
942 		(*obj)->data = outbuf;
943 	} else {
944 		struct stat sb;
945 		if (fstat(*outfd, &sb) == -1) {
946 			err = got_error_from_errno("fstat");
947 			goto done;
948 		}
949 
950 		if (sb.st_size != tot) {
951 			err = got_error(GOT_ERR_PRIVSEP_LEN);
952 			goto done;
953 		}
954 #ifndef GOT_PACK_NO_MMAP
955 		if (tot > 0 && tot <= SIZE_MAX) {
956 			(*obj)->data = mmap(NULL, tot, PROT_READ,
957 			    MAP_PRIVATE, *outfd, 0);
958 			if ((*obj)->data == MAP_FAILED) {
959 				if (errno != ENOMEM) {
960 					err = got_error_from_errno("mmap");
961 					goto done;
962 				}
963 				(*obj)->data = NULL;
964 			} else {
965 				(*obj)->fd = *outfd;
966 				*outfd = -1;
967 			}
968 		}
969 #endif
970 		if (*outfd != -1) {
971 			(*obj)->f = fdopen(*outfd, "r");
972 			if ((*obj)->f == NULL) {
973 				err = got_error_from_errno("fdopen");
974 				goto done;
975 			}
976 			*outfd = -1;
977 		}
978 	}
979 	(*obj)->hdrlen = hdrlen;
980 	(*obj)->size = size;
981 done:
982 	if (err) {
983 		if (*obj) {
984 			got_object_raw_close(*obj);
985 			*obj = NULL;
986 		}
987 	} else
988 		(*obj)->refcnt++;
989 	return err;
990 }