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Date:: Thu Feb 21 14:17:36 2019 UTC
Message:: prevent double-close(2) of file descriptors passed in imsg
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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/uio.h>
21 #include <sys/socket.h>
22 #include <sys/wait.h>
23 #include <sys/syslimits.h>
24 
25 #include <errno.h>
26 #include <fcntl.h>
27 #include <stdio.h>
28 #include <stdlib.h>
29 #include <string.h>
30 #include <stdint.h>
31 #include <sha1.h>
32 #include <zlib.h>
33 #include <ctype.h>
34 #include <limits.h>
35 #include <imsg.h>
36 #include <time.h>
37 
38 #include "got_error.h"
39 #include "got_object.h"
40 #include "got_repository.h"
41 #include "got_opentemp.h"
42 
43 #include "got_lib_sha1.h"
44 #include "got_lib_delta.h"
45 #include "got_lib_path.h"
46 #include "got_lib_inflate.h"
47 #include "got_lib_object.h"
48 #include "got_lib_privsep.h"
49 #include "got_lib_object_idcache.h"
50 #include "got_lib_object_cache.h"
51 #include "got_lib_object_parse.h"
52 #include "got_lib_pack.h"
53 #include "got_lib_repository.h"
54 
55 #ifndef MIN
56 #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
57 #endif
58 
59 struct got_object_id *
60 got_object_id_dup(struct got_object_id *id1)
61 {
62 	struct got_object_id *id2;
63 
64 	id2 = malloc(sizeof(*id2));
65 	if (id2 == NULL)
66 		return NULL;
67 	memcpy(id2, id1, sizeof(*id2));
68 	return id2;
69 }
70 
71 struct got_object_id *
72 got_object_get_id(struct got_object *obj)
73 {
74 	return &obj->id;
75 }
76 
77 const struct got_error *
78 got_object_get_id_str(char **outbuf, struct got_object *obj)
79 {
80 	return got_object_id_str(outbuf, &obj->id);
81 }
82 
83 const struct got_error *
84 got_object_get_type(int *type, struct got_repository *repo,
85     struct got_object_id *id)
86 {
87 	const struct got_error *err = NULL;
88 	struct got_object *obj;
89 
90 	err = got_object_open(&obj, repo, id);
91 	if (err)
92 		return err;
93 
94 	switch (obj->type) {
95 	case GOT_OBJ_TYPE_COMMIT:
96 	case GOT_OBJ_TYPE_TREE:
97 	case GOT_OBJ_TYPE_BLOB:
98 	case GOT_OBJ_TYPE_TAG:
99 		*type = obj->type;
100 		break;
101 	default:
102 		err = got_error(GOT_ERR_OBJ_TYPE);
103 		break;
104 	}
105 
106 	got_object_close(obj);
107 	return err;
108 }
109 
110 static const struct got_error *
111 object_path(char **path, struct got_object_id *id, struct got_repository *repo)
112 {
113 	const struct got_error *err = NULL;
114 	char *hex = NULL;
115 	char *path_objects = got_repo_get_path_objects(repo);
116 
117 	*path = NULL;
118 
119 	if (path_objects == NULL)
120 		return got_error_from_errno();
121 
122 	err = got_object_id_str(&hex, id);
123 	if (err)
124 		goto done;
125 
126 	if (asprintf(path, "%s/%.2x/%s", path_objects,
127 	    id->sha1[0], hex + 2) == -1)
128 		err = got_error_from_errno();
129 
130 done:
131 	free(hex);
132 	free(path_objects);
133 	return err;
134 }
135 
136 static const struct got_error *
137 open_loose_object(int *fd, struct got_object_id *id,
138     struct got_repository *repo)
139 {
140 	const struct got_error *err = NULL;
141 	char *path;
142 
143 	err = object_path(&path, id, repo);
144 	if (err)
145 		return err;
146 	*fd = open(path, O_RDONLY | O_NOFOLLOW, GOT_DEFAULT_FILE_MODE);
147 	if (*fd == -1) {
148 		err = got_error_from_errno();
149 		goto done;
150 	}
151 done:
152 	free(path);
153 	return err;
154 }
155 
156 static const struct got_error *
157 get_packfile_path(char **path_packfile, struct got_packidx *packidx)
158 {
159 	size_t size;
160 
161 	/* Packfile path contains ".pack" instead of ".idx", so add one byte. */
162 	size = strlen(packidx->path_packidx) + 2;
163 	if (size < GOT_PACKFILE_NAMELEN + 1)
164 		return got_error(GOT_ERR_BAD_PATH);
165 
166 	*path_packfile = malloc(size);
167 	if (*path_packfile == NULL)
168 		return got_error_from_errno();
169 
170 	/* Copy up to and excluding ".idx". */
171 	if (strlcpy(*path_packfile, packidx->path_packidx,
172 	    size - strlen(GOT_PACKIDX_SUFFIX) - 1) >= size)
173 		return got_error(GOT_ERR_NO_SPACE);
174 
175 	if (strlcat(*path_packfile, GOT_PACKFILE_SUFFIX, size) >= size)
176 		return got_error(GOT_ERR_NO_SPACE);
177 
178 	return NULL;
179 }
180 
181 static void
182 exec_privsep_child(int imsg_fds[2], const char *path, const char *repo_path)
183 {
184 	if (close(imsg_fds[0]) != 0) {
185 		fprintf(stderr, "%s: %s\n", getprogname(),
186 		    strerror(errno));
187 		_exit(1);
188 	}
189 
190 	if (dup2(imsg_fds[1], GOT_IMSG_FD_CHILD) == -1) {
191 		fprintf(stderr, "%s: %s\n", getprogname(),
192 		    strerror(errno));
193 		_exit(1);
194 	}
195 	if (closefrom(GOT_IMSG_FD_CHILD + 1) == -1) {
196 		fprintf(stderr, "%s: %s\n", getprogname(),
197 		    strerror(errno));
198 		_exit(1);
199 	}
200 
201 	if (execl(path, path, repo_path, (char *)NULL) == -1) {
202 		fprintf(stderr, "%s: %s: %s\n", getprogname(), path,
203 		    strerror(errno));
204 		_exit(1);
205 	}
206 }
207 
208 static const struct got_error *
209 request_packed_object(struct got_object **obj, struct got_pack *pack, int idx,
210     struct got_object_id *id)
211 {
212 	const struct got_error *err = NULL;
213 	struct imsgbuf *ibuf = pack->privsep_child->ibuf;
214 
215 	err = got_privsep_send_packed_obj_req(ibuf, idx, id);
216 	if (err)
217 		return err;
218 
219 	err = got_privsep_recv_obj(obj, ibuf);
220 	if (err)
221 		return err;
222 
223 	(*obj)->path_packfile = strdup(pack->path_packfile);
224 	if ((*obj)->path_packfile == NULL) {
225 		err = got_error_from_errno();
226 		return err;
227 	}
228 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
229 
230 	return NULL;
231 }
232 
233 static const struct got_error *
234 start_pack_privsep_child(struct got_pack *pack, struct got_packidx *packidx)
235 {
236 	const struct got_error *err = NULL;
237 	int imsg_fds[2];
238 	pid_t pid;
239 	struct imsgbuf *ibuf;
240 
241 	ibuf = calloc(1, sizeof(*ibuf));
242 	if (ibuf == NULL)
243 		return got_error_from_errno();
244 
245 	pack->privsep_child = calloc(1, sizeof(*pack->privsep_child));
246 	if (pack->privsep_child == NULL) {
247 		err = got_error_from_errno();
248 		free(ibuf);
249 		return err;
250 	}
251 
252 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1) {
253 		err = got_error_from_errno();
254 		goto done;
255 	}
256 
257 	pid = fork();
258 	if (pid == -1) {
259 		err = got_error_from_errno();
260 		goto done;
261 	} else if (pid == 0) {
262 		exec_privsep_child(imsg_fds, GOT_PATH_PROG_READ_PACK,
263 		    pack->path_packfile);
264 		/* not reached */
265 	}
266 
267 	if (close(imsg_fds[1]) != 0)
268 		return got_error_from_errno();
269 	pack->privsep_child->imsg_fd = imsg_fds[0];
270 	pack->privsep_child->pid = pid;
271 	imsg_init(ibuf, imsg_fds[0]);
272 	pack->privsep_child->ibuf = ibuf;
273 
274 	err = got_privsep_init_pack_child(ibuf, pack, packidx);
275 	if (err) {
276 		const struct got_error *child_err;
277 		err = got_privsep_send_stop(pack->privsep_child->imsg_fd);
278 		child_err = got_privsep_wait_for_child(
279 		    pack->privsep_child->pid);
280 		if (child_err && err == NULL)
281 			err = child_err;
282 	}
283 done:
284 	if (err) {
285 		free(ibuf);
286 		free(pack->privsep_child);
287 		pack->privsep_child = NULL;
288 	}
289 	return err;
290 }
291 
292 static const struct got_error *
293 read_packed_object_privsep(struct got_object **obj,
294     struct got_repository *repo, struct got_pack *pack,
295     struct got_packidx *packidx, int idx, struct got_object_id *id)
296 {
297 	const struct got_error *err = NULL;
298 
299 	if (pack->privsep_child)
300 		return request_packed_object(obj, pack, idx, id);
301 
302 	err = start_pack_privsep_child(pack, packidx);
303 	if (err)
304 		return err;
305 
306 	return request_packed_object(obj, pack, idx, id);
307 }
308 
309 
310 static const struct got_error *
311 open_packed_object(struct got_object **obj, struct got_object_id *id,
312     struct got_repository *repo)
313 {
314 	const struct got_error *err = NULL;
315 	struct got_pack *pack = NULL;
316 	struct got_packidx *packidx = NULL;
317 	int idx;
318 	char *path_packfile;
319 
320 	err = got_repo_search_packidx(&packidx, &idx, repo, id);
321 	if (err)
322 		return err;
323 
324 	err = get_packfile_path(&path_packfile, packidx);
325 	if (err)
326 		return err;
327 
328 	pack = got_repo_get_cached_pack(repo, path_packfile);
329 	if (pack == NULL) {
330 		err = got_repo_cache_pack(&pack, repo, path_packfile, packidx);
331 		if (err)
332 			goto done;
333 	}
334 
335 	err = read_packed_object_privsep(obj, repo, pack, packidx, idx, id);
336 	if (err)
337 		goto done;
338 
339 	err = got_repo_cache_pack(NULL, repo, (*obj)->path_packfile, packidx);
340 done:
341 	free(path_packfile);
342 	return err;
343 }
344 
345 static const struct got_error *
346 request_object(struct got_object **obj, struct got_repository *repo, int fd)
347 {
348 	const struct got_error *err = NULL;
349 	struct imsgbuf *ibuf;
350 
351 	ibuf = repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_OBJECT].ibuf;
352 
353 	err = got_privsep_send_obj_req(ibuf, fd);
354 	if (err)
355 		return err;
356 
357 	return got_privsep_recv_obj(obj, ibuf);
358 }
359 
360 static const struct got_error *
361 read_object_header_privsep(struct got_object **obj, struct got_repository *repo,
362     int obj_fd)
363 {
364 	int imsg_fds[2];
365 	pid_t pid;
366 	struct imsgbuf *ibuf;
367 
368 	if (repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_OBJECT].imsg_fd != -1)
369 		return request_object(obj, repo, obj_fd);
370 
371 	ibuf = calloc(1, sizeof(*ibuf));
372 	if (ibuf == NULL)
373 		return got_error_from_errno();
374 
375 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1)
376 		return got_error_from_errno();
377 
378 	pid = fork();
379 	if (pid == -1)
380 		return got_error_from_errno();
381 	else if (pid == 0) {
382 		exec_privsep_child(imsg_fds, GOT_PATH_PROG_READ_OBJECT,
383 		    repo->path);
384 		/* not reached */
385 	}
386 
387 	if (close(imsg_fds[1]) != 0)
388 		return got_error_from_errno();
389 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_OBJECT].imsg_fd =
390 	    imsg_fds[0];
391 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_OBJECT].pid = pid;
392 	imsg_init(ibuf, imsg_fds[0]);
393 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_OBJECT].ibuf = ibuf;
394 
395 	return request_object(obj, repo, obj_fd);
396 }
397 
398 
399 const struct got_error *
400 got_object_open(struct got_object **obj, struct got_repository *repo,
401     struct got_object_id *id)
402 {
403 	const struct got_error *err = NULL;
404 	char *path;
405 	int fd;
406 
407 	*obj = got_repo_get_cached_object(repo, id);
408 	if (*obj != NULL) {
409 		(*obj)->refcnt++;
410 		return NULL;
411 	}
412 
413 	err = open_packed_object(obj, id, repo);
414 	if (err && err->code != GOT_ERR_NO_OBJ)
415 		return err;
416 	if (*obj) {
417 		(*obj)->refcnt++;
418 		return got_repo_cache_object(repo, id, *obj);
419 	}
420 
421 	err = object_path(&path, id, repo);
422 	if (err)
423 		return err;
424 
425 	fd = open(path, O_RDONLY | O_NOFOLLOW, GOT_DEFAULT_FILE_MODE);
426 	if (fd == -1) {
427 		if (errno == ENOENT)
428 			err = got_error_no_obj(id);
429 		else
430 			err = got_error_from_errno();
431 		goto done;
432 	} else {
433 		err = read_object_header_privsep(obj, repo, fd);
434 		if (err)
435 			goto done;
436 		memcpy((*obj)->id.sha1, id->sha1, SHA1_DIGEST_LENGTH);
437 	}
438 
439 	(*obj)->refcnt++;
440 	err = got_repo_cache_object(repo, id, *obj);
441 done:
442 	free(path);
443 	return err;
444 
445 }
446 
447 const struct got_error *
448 got_object_open_by_id_str(struct got_object **obj, struct got_repository *repo,
449     const char *id_str)
450 {
451 	struct got_object_id id;
452 
453 	if (!got_parse_sha1_digest(id.sha1, id_str))
454 		return got_error(GOT_ERR_BAD_OBJ_ID_STR);
455 
456 	return got_object_open(obj, repo, &id);
457 }
458 
459 const struct got_error *
460 got_object_resolve_id_str(struct got_object_id **id,
461     struct got_repository *repo, const char *id_str)
462 {
463 	const struct got_error *err = NULL;
464 	struct got_object *obj;
465 
466 	err = got_object_open_by_id_str(&obj, repo, id_str);
467 	if (err)
468 		return err;
469 
470 	*id = got_object_id_dup(got_object_get_id(obj));
471 	got_object_close(obj);
472 	if (*id == NULL)
473 		return got_error_from_errno();
474 
475 	return NULL;
476 }
477 
478 static const struct got_error *
479 request_packed_commit(struct got_commit_object **commit, struct got_pack *pack,
480     int pack_idx, struct got_object_id *id)
481 {
482 	const struct got_error *err = NULL;
483 
484 	err = got_privsep_send_commit_req(pack->privsep_child->ibuf, -1, id,
485 	    pack_idx);
486 	if (err)
487 		return err;
488 
489 	return got_privsep_recv_commit(commit, pack->privsep_child->ibuf);
490 }
491 
492 static const struct got_error *
493 read_packed_commit_privsep(struct got_commit_object **commit,
494     struct got_pack *pack, struct got_packidx *packidx, int idx,
495     struct got_object_id *id)
496 {
497 	const struct got_error *err = NULL;
498 
499 	if (pack->privsep_child)
500 		return request_packed_commit(commit, pack, idx, id);
501 
502 	err = start_pack_privsep_child(pack, packidx);
503 	if (err)
504 		return err;
505 
506 	return request_packed_commit(commit, pack, idx, id);
507 }
508 
509 static const struct got_error *
510 request_commit(struct got_commit_object **commit, struct got_repository *repo,
511     int fd)
512 {
513 	const struct got_error *err = NULL;
514 	struct imsgbuf *ibuf;
515 
516 	ibuf = repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_COMMIT].ibuf;
517 
518 	err = got_privsep_send_commit_req(ibuf, fd, NULL, -1);
519 	if (err)
520 		return err;
521 
522 	return got_privsep_recv_commit(commit, ibuf);
523 }
524 
525 static const struct got_error *
526 read_commit_privsep(struct got_commit_object **commit, int obj_fd,
527     struct got_repository *repo)
528 {
529 	int imsg_fds[2];
530 	pid_t pid;
531 	struct imsgbuf *ibuf;
532 
533 	if (repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_COMMIT].imsg_fd != -1)
534 		return request_commit(commit, repo, obj_fd);
535 
536 	ibuf = calloc(1, sizeof(*ibuf));
537 	if (ibuf == NULL)
538 		return got_error_from_errno();
539 
540 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1)
541 		return got_error_from_errno();
542 
543 	pid = fork();
544 	if (pid == -1)
545 		return got_error_from_errno();
546 	else if (pid == 0) {
547 		exec_privsep_child(imsg_fds, GOT_PATH_PROG_READ_COMMIT,
548 		    repo->path);
549 		/* not reached */
550 	}
551 
552 	if (close(imsg_fds[1]) != 0)
553 		return got_error_from_errno();
554 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_COMMIT].imsg_fd =
555 	    imsg_fds[0];
556 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_COMMIT].pid = pid;
557 	imsg_init(ibuf, imsg_fds[0]);
558 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_COMMIT].ibuf = ibuf;
559 
560 	return request_commit(commit, repo, obj_fd);
561 }
562 
563 
564 static const struct got_error *
565 open_commit(struct got_commit_object **commit,
566     struct got_repository *repo, struct got_object_id *id, int check_cache)
567 {
568 	const struct got_error *err = NULL;
569 	struct got_packidx *packidx = NULL;
570 	int idx;
571 	char *path_packfile;
572 
573 	if (check_cache) {
574 		*commit = got_repo_get_cached_commit(repo, id);
575 		if (*commit != NULL) {
576 			(*commit)->refcnt++;
577 			return NULL;
578 		}
579 	} else
580 		*commit = NULL;
581 
582 	err = got_repo_search_packidx(&packidx, &idx, repo, id);
583 	if (err == NULL) {
584 		struct got_pack *pack = NULL;
585 
586 		err = get_packfile_path(&path_packfile, packidx);
587 		if (err)
588 			return err;
589 
590 		pack = got_repo_get_cached_pack(repo, path_packfile);
591 		if (pack == NULL) {
592 			err = got_repo_cache_pack(&pack, repo, path_packfile,
593 			    packidx);
594 			if (err)
595 				return err;
596 		}
597 		err = read_packed_commit_privsep(commit, pack,
598 		    packidx, idx, id);
599 	} else if (err->code == GOT_ERR_NO_OBJ) {
600 		int fd;
601 
602 		err = open_loose_object(&fd, id, repo);
603 		if (err)
604 			return err;
605 		err = read_commit_privsep(commit, fd, repo);
606 	}
607 
608 	if (err == NULL) {
609 		(*commit)->refcnt++;
610 		err = got_repo_cache_commit(repo, id, *commit);
611 	}
612 
613 	return err;
614 }
615 
616 const struct got_error *
617 got_object_open_as_commit(struct got_commit_object **commit,
618     struct got_repository *repo, struct got_object_id *id)
619 {
620 	*commit = got_repo_get_cached_commit(repo, id);
621 	if (*commit != NULL) {
622 		(*commit)->refcnt++;
623 		return NULL;
624 	}
625 
626 	return open_commit(commit, repo, id, 0);
627 }
628 
629 const struct got_error *
630 got_object_commit_open(struct got_commit_object **commit,
631     struct got_repository *repo, struct got_object *obj)
632 {
633 	return open_commit(commit, repo, got_object_get_id(obj), 1);
634 }
635 
636 const struct got_error *
637 got_object_qid_alloc(struct got_object_qid **qid, struct got_object_id *id)
638 {
639 	const struct got_error *err = NULL;
640 
641 	*qid = calloc(1, sizeof(**qid));
642 	if (*qid == NULL)
643 		return got_error_from_errno();
644 
645 	(*qid)->id = got_object_id_dup(id);
646 	if ((*qid)->id == NULL) {
647 		err = got_error_from_errno();
648 		got_object_qid_free(*qid);
649 		*qid = NULL;
650 		return err;
651 	}
652 
653 	return NULL;
654 }
655 
656 static const struct got_error *
657 request_packed_tree(struct got_tree_object **tree, struct got_pack *pack,
658     int pack_idx, struct got_object_id *id)
659 {
660 	const struct got_error *err = NULL;
661 
662 	err = got_privsep_send_tree_req(pack->privsep_child->ibuf, -1, id,
663 	    pack_idx);
664 	if (err)
665 		return err;
666 
667 	return got_privsep_recv_tree(tree, pack->privsep_child->ibuf);
668 }
669 
670 static const struct got_error *
671 read_packed_tree_privsep(struct got_tree_object **tree,
672     struct got_pack *pack, struct got_packidx *packidx, int idx,
673     struct got_object_id *id)
674 {
675 	const struct got_error *err = NULL;
676 
677 	if (pack->privsep_child)
678 		return request_packed_tree(tree, pack, idx, id);
679 
680 	err = start_pack_privsep_child(pack, packidx);
681 	if (err)
682 		return err;
683 
684 	return request_packed_tree(tree, pack, idx, id);
685 }
686 
687 static const struct got_error *
688 request_tree(struct got_tree_object **tree, struct got_repository *repo,
689     int fd)
690 {
691 	const struct got_error *err = NULL;
692 	struct imsgbuf *ibuf;
693 
694 	ibuf = repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_TREE].ibuf;
695 
696 	err = got_privsep_send_tree_req(ibuf, fd, NULL, -1);
697 	if (err)
698 		return err;
699 
700 	return got_privsep_recv_tree(tree, ibuf);
701 }
702 
703 const struct got_error *
704 read_tree_privsep(struct got_tree_object **tree, int obj_fd,
705     struct got_repository *repo)
706 {
707 	int imsg_fds[2];
708 	pid_t pid;
709 	struct imsgbuf *ibuf;
710 
711 	if (repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_TREE].imsg_fd != -1)
712 		return request_tree(tree, repo, obj_fd);
713 
714 	ibuf = calloc(1, sizeof(*ibuf));
715 	if (ibuf == NULL)
716 		return got_error_from_errno();
717 
718 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1)
719 		return got_error_from_errno();
720 
721 	pid = fork();
722 	if (pid == -1)
723 		return got_error_from_errno();
724 	else if (pid == 0) {
725 		exec_privsep_child(imsg_fds, GOT_PATH_PROG_READ_TREE,
726 		    repo->path);
727 		/* not reached */
728 	}
729 
730 	if (close(imsg_fds[1]) != 0)
731 		return got_error_from_errno();
732 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_TREE].imsg_fd =
733 	    imsg_fds[0];
734 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_TREE].pid = pid;
735 	imsg_init(ibuf, imsg_fds[0]);
736 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_TREE].ibuf = ibuf;
737 
738 
739 	return request_tree(tree, repo, obj_fd);
740 }
741 
742 static const struct got_error *
743 open_tree(struct got_tree_object **tree, struct got_repository *repo,
744     struct got_object_id *id, int check_cache)
745 {
746 	const struct got_error *err = NULL;
747 	struct got_packidx *packidx = NULL;
748 	int idx;
749 	char *path_packfile;
750 
751 	if (check_cache) {
752 		*tree = got_repo_get_cached_tree(repo, id);
753 		if (*tree != NULL) {
754 			(*tree)->refcnt++;
755 			return NULL;
756 		}
757 	} else
758 		*tree = NULL;
759 
760 	err = got_repo_search_packidx(&packidx, &idx, repo, id);
761 	if (err == NULL) {
762 		struct got_pack *pack = NULL;
763 
764 		err = get_packfile_path(&path_packfile, packidx);
765 		if (err)
766 			return err;
767 
768 		pack = got_repo_get_cached_pack(repo, path_packfile);
769 		if (pack == NULL) {
770 			err = got_repo_cache_pack(&pack, repo, path_packfile,
771 			    packidx);
772 			if (err)
773 				return err;
774 		}
775 		err = read_packed_tree_privsep(tree, pack,
776 		    packidx, idx, id);
777 	} else if (err->code == GOT_ERR_NO_OBJ) {
778 		int fd;
779 
780 		err = open_loose_object(&fd, id, repo);
781 		if (err)
782 			return err;
783 		err = read_tree_privsep(tree, fd, repo);
784 	}
785 
786 	if (err == NULL) {
787 		(*tree)->refcnt++;
788 		err = got_repo_cache_tree(repo, id, *tree);
789 	}
790 
791 	return err;
792 }
793 
794 const struct got_error *
795 got_object_open_as_tree(struct got_tree_object **tree,
796     struct got_repository *repo, struct got_object_id *id)
797 {
798 	*tree = got_repo_get_cached_tree(repo, id);
799 	if (*tree != NULL) {
800 		(*tree)->refcnt++;
801 		return NULL;
802 	}
803 
804 	return open_tree(tree, repo, id, 0);
805 }
806 
807 const struct got_error *
808 got_object_tree_open(struct got_tree_object **tree,
809     struct got_repository *repo, struct got_object *obj)
810 {
811 	return open_tree(tree, repo, got_object_get_id(obj), 1);
812 }
813 
814 const struct got_tree_entries *
815 got_object_tree_get_entries(struct got_tree_object *tree)
816 {
817 	return &tree->entries;
818 }
819 
820 static const struct got_error *
821 request_packed_blob(uint8_t **outbuf, size_t *size, size_t *hdrlen, int outfd,
822     struct got_pack *pack, struct got_packidx *packidx, int idx,
823     struct got_object_id *id)
824 {
825 	const struct got_error *err = NULL;
826 	int outfd_child;
827 	int basefd, accumfd; /* temporary files for delta application */
828 
829 	basefd = got_opentempfd();
830 	if (basefd == -1)
831 		return got_error_from_errno();
832 	accumfd = got_opentempfd();
833 	if (accumfd == -1)
834 		return got_error_from_errno();
835 
836 	outfd_child = dup(outfd);
837 	if (outfd_child == -1)
838 		return got_error_from_errno();
839 
840 	err = got_privsep_send_blob_req(pack->privsep_child->ibuf, -1, id, idx);
841 	if (err)
842 		return err;
843 
844 	err = got_privsep_send_blob_outfd(pack->privsep_child->ibuf,
845 	    outfd_child);
846 	if (err) {
847 		close(basefd);
848 		close(accumfd);
849 		return err;
850 	}
851 
852 	err = got_privsep_send_tmpfd(pack->privsep_child->ibuf,
853 	    basefd);
854 	if (err) {
855 		close(accumfd);
856 		return err;
857 	}
858 
859 	err = got_privsep_send_tmpfd(pack->privsep_child->ibuf,
860 	    accumfd);
861 	if (err)
862 		return err;
863 
864 	err = got_privsep_recv_blob(outbuf, size, hdrlen,
865 	    pack->privsep_child->ibuf);
866 	if (err)
867 		return err;
868 
869 	if (lseek(outfd, SEEK_SET, 0) == -1)
870 		err = got_error_from_errno();
871 
872 	return err;
873 }
874 
875 static const struct got_error *
876 read_packed_blob_privsep(uint8_t **outbuf, size_t *size, size_t *hdrlen,
877     int outfd, struct got_pack *pack, struct got_packidx *packidx, int idx,
878     struct got_object_id *id)
879 {
880 	const struct got_error *err = NULL;
881 
882 	if (pack->privsep_child == NULL) {
883 		err = start_pack_privsep_child(pack, packidx);
884 		if (err)
885 			return err;
886 	}
887 
888 	return request_packed_blob(outbuf, size, hdrlen, outfd, pack, packidx,
889 	    idx, id);
890 }
891 
892 static const struct got_error *
893 request_blob(uint8_t **outbuf, size_t *size, size_t *hdrlen, int outfd,
894     int infd, struct imsgbuf *ibuf)
895 {
896 	const struct got_error *err = NULL;
897 	int outfd_child;
898 
899 	outfd_child = dup(outfd);
900 	if (outfd_child == -1)
901 		return got_error_from_errno();
902 
903 	err = got_privsep_send_blob_req(ibuf, infd, NULL, -1);
904 	if (err)
905 		return err;
906 
907 	err = got_privsep_send_blob_outfd(ibuf, outfd_child);
908 	if (err)
909 		return err;
910 
911 	err = got_privsep_recv_blob(outbuf, size, hdrlen, ibuf);
912 	if (err)
913 		return err;
914 
915 	if (lseek(outfd, SEEK_SET, 0) == -1)
916 		return got_error_from_errno();
917 
918 	return err;
919 }
920 
921 static const struct got_error *
922 read_blob_privsep(uint8_t **outbuf, size_t *size, size_t *hdrlen,
923     int outfd, int infd, struct got_repository *repo)
924 {
925 	int imsg_fds[2];
926 	pid_t pid;
927 	struct imsgbuf *ibuf;
928 
929 	if (repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_BLOB].imsg_fd != -1) {
930 		ibuf = repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_BLOB].ibuf;
931 		return request_blob(outbuf, size, hdrlen, outfd, infd, ibuf);
932 	}
933 
934 	ibuf = calloc(1, sizeof(*ibuf));
935 	if (ibuf == NULL)
936 		return got_error_from_errno();
937 
938 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1)
939 		return got_error_from_errno();
940 
941 	pid = fork();
942 	if (pid == -1)
943 		return got_error_from_errno();
944 	else if (pid == 0) {
945 		exec_privsep_child(imsg_fds, GOT_PATH_PROG_READ_BLOB,
946 		    repo->path);
947 		/* not reached */
948 	}
949 
950 	if (close(imsg_fds[1]) != 0)
951 		return got_error_from_errno();
952 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_BLOB].imsg_fd =
953 	    imsg_fds[0];
954 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_BLOB].pid = pid;
955 	imsg_init(ibuf, imsg_fds[0]);
956 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_BLOB].ibuf = ibuf;
957 
958 	return request_blob(outbuf, size, hdrlen, outfd, infd, ibuf);
959 }
960 
961 static const struct got_error *
962 open_blob(struct got_blob_object **blob, struct got_repository *repo,
963     struct got_object_id *id, size_t blocksize)
964 {
965 	const struct got_error *err = NULL;
966 	struct got_packidx *packidx = NULL;
967 	int idx;
968 	char *path_packfile;
969 	uint8_t *outbuf;
970 	int outfd;
971 	size_t size, hdrlen;
972 	struct stat sb;
973 
974 	*blob = calloc(1, sizeof(**blob));
975 	if (*blob == NULL)
976 		return got_error_from_errno();
977 
978 	outfd = got_opentempfd();
979 	if (outfd == -1)
980 		return got_error_from_errno();
981 
982 	(*blob)->read_buf = malloc(blocksize);
983 	if ((*blob)->read_buf == NULL) {
984 		err = got_error_from_errno();
985 		goto done;
986 	}
987 
988 	err = got_repo_search_packidx(&packidx, &idx, repo, id);
989 	if (err == NULL) {
990 		struct got_pack *pack = NULL;
991 
992 		err = get_packfile_path(&path_packfile, packidx);
993 		if (err)
994 			goto done;
995 
996 		pack = got_repo_get_cached_pack(repo, path_packfile);
997 		if (pack == NULL) {
998 			err = got_repo_cache_pack(&pack, repo, path_packfile,
999 			    packidx);
1000 			if (err)
1001 				goto done;
1002 		}
1003 		err = read_packed_blob_privsep(&outbuf, &size, &hdrlen, outfd,
1004 		    pack, packidx, idx, id);
1005 	} else if (err->code == GOT_ERR_NO_OBJ) {
1006 		int infd;
1007 
1008 		err = open_loose_object(&infd, id, repo);
1009 		if (err)
1010 			goto done;
1011 		err = read_blob_privsep(&outbuf, &size, &hdrlen, outfd, infd,
1012 		    repo);
1013 	}
1014 	if (err)
1015 		goto done;
1016 
1017 	if (hdrlen > size) {
1018 		err = got_error(GOT_ERR_BAD_OBJ_HDR);
1019 		goto done;
1020 	}
1021 
1022 	if (outbuf) {
1023 		if (close(outfd) != 0 && err == NULL)
1024 			err = got_error_from_errno();
1025 		outfd = -1;
1026 		(*blob)->f = fmemopen(outbuf, size, "rb");
1027 		if ((*blob)->f == NULL) {
1028 			err = got_error_from_errno();
1029 			free(outbuf);
1030 			goto done;
1031 		}
1032 		(*blob)->data = outbuf;
1033 	} else {
1034 		if (fstat(outfd, &sb) == -1) {
1035 			err = got_error_from_errno();
1036 			goto done;
1037 		}
1038 
1039 		if (sb.st_size != size) {
1040 			err = got_error(GOT_ERR_PRIVSEP_LEN);
1041 			goto done;
1042 		}
1043 
1044 		(*blob)->f = fdopen(outfd, "rb");
1045 		if ((*blob)->f == NULL) {
1046 			err = got_error_from_errno();
1047 			close(outfd);
1048 			outfd = -1;
1049 			goto done;
1050 		}
1051 	}
1052 
1053 	(*blob)->hdrlen = hdrlen;
1054 	(*blob)->blocksize = blocksize;
1055 	memcpy(&(*blob)->id.sha1, id->sha1, SHA1_DIGEST_LENGTH);
1056 
1057 done:
1058 	if (err) {
1059 		if (*blob) {
1060 			if ((*blob)->f)
1061 				fclose((*blob)->f);
1062 			free((*blob)->read_buf);
1063 			free((*blob)->data);
1064 			free(*blob);
1065 			*blob = NULL;
1066 		} else if (outfd != -1)
1067 			close(outfd);
1068 	}
1069 	return err;
1070 }
1071 
1072 const struct got_error *
1073 got_object_open_as_blob(struct got_blob_object **blob,
1074     struct got_repository *repo, struct got_object_id *id,
1075     size_t blocksize)
1076 {
1077 	return open_blob(blob, repo, id, blocksize);
1078 }
1079 
1080 const struct got_error *
1081 got_object_blob_open(struct got_blob_object **blob,
1082     struct got_repository *repo, struct got_object *obj, size_t blocksize)
1083 {
1084 	return open_blob(blob, repo, got_object_get_id(obj), blocksize);
1085 }
1086 
1087 const struct got_error *
1088 got_object_blob_close(struct got_blob_object *blob)
1089 {
1090 	const struct got_error *err = NULL;
1091 	free(blob->read_buf);
1092 	if (fclose(blob->f) != 0)
1093 		err = got_error_from_errno();
1094 	free(blob->data);
1095 	free(blob);
1096 	return err;
1097 }
1098 
1099 char *
1100 got_object_blob_id_str(struct got_blob_object *blob, char *buf, size_t size)
1101 {
1102 	return got_sha1_digest_to_str(blob->id.sha1, buf, size);
1103 }
1104 
1105 size_t
1106 got_object_blob_get_hdrlen(struct got_blob_object *blob)
1107 {
1108 	return blob->hdrlen;
1109 }
1110 
1111 const uint8_t *
1112 got_object_blob_get_read_buf(struct got_blob_object *blob)
1113 {
1114 	return blob->read_buf;
1115 }
1116 
1117 const struct got_error *
1118 got_object_blob_read_block(size_t *outlenp, struct got_blob_object *blob)
1119 {
1120 	size_t n;
1121 
1122 	n = fread(blob->read_buf, 1, blob->blocksize, blob->f);
1123 	if (n == 0 && ferror(blob->f))
1124 		return got_ferror(blob->f, GOT_ERR_IO);
1125 	*outlenp = n;
1126 	return NULL;
1127 }
1128 
1129 const struct got_error *
1130 got_object_blob_dump_to_file(size_t *total_len, int *nlines,
1131     FILE *outfile, struct got_blob_object *blob)
1132 {
1133 	const struct got_error *err = NULL;
1134 	size_t n, len, hdrlen;
1135 	const uint8_t *buf;
1136 	int i;
1137 
1138 	if (total_len)
1139 		*total_len = 0;
1140 	if (nlines)
1141 		*nlines = 0;
1142 
1143 	hdrlen = got_object_blob_get_hdrlen(blob);
1144 	do {
1145 		err = got_object_blob_read_block(&len, blob);
1146 		if (err)
1147 			return err;
1148 		if (len == 0)
1149 			break;
1150 		if (total_len)
1151 			*total_len += len;
1152 		buf = got_object_blob_get_read_buf(blob);
1153 		if (nlines) {
1154 			for (i = 0; i < len; i++) {
1155 				if (buf[i] == '\n')
1156 					(*nlines)++;
1157 			}
1158 		}
1159 		/* Skip blob object header first time around. */
1160 		n = fwrite(buf + hdrlen, 1, len - hdrlen, outfile);
1161 		if (n != len - hdrlen)
1162 			return got_ferror(outfile, GOT_ERR_IO);
1163 		hdrlen = 0;
1164 	} while (len != 0);
1165 
1166 	if (fflush(outfile) != 0)
1167 		return got_error_from_errno();
1168 	rewind(outfile);
1169 
1170 	return NULL;
1171 }
1172 
1173 static const struct got_error *
1174 request_packed_tag(struct got_tag_object **tag, struct got_pack *pack,
1175     int pack_idx, struct got_object_id *id)
1176 {
1177 	const struct got_error *err = NULL;
1178 
1179 	err = got_privsep_send_tag_req(pack->privsep_child->ibuf, -1, id,
1180 	    pack_idx);
1181 	if (err)
1182 		return err;
1183 
1184 	return got_privsep_recv_tag(tag, pack->privsep_child->ibuf);
1185 }
1186 
1187 static const struct got_error *
1188 read_packed_tag_privsep(struct got_tag_object **tag,
1189     struct got_pack *pack, struct got_packidx *packidx, int idx,
1190     struct got_object_id *id)
1191 {
1192 	const struct got_error *err = NULL;
1193 
1194 	if (pack->privsep_child)
1195 		return request_packed_tag(tag, pack, idx, id);
1196 
1197 	err = start_pack_privsep_child(pack, packidx);
1198 	if (err)
1199 		return err;
1200 
1201 	return request_packed_tag(tag, pack, idx, id);
1202 }
1203 
1204 static const struct got_error *
1205 request_tag(struct got_tag_object **tag, struct got_repository *repo,
1206     int fd)
1207 {
1208 	const struct got_error *err = NULL;
1209 	struct imsgbuf *ibuf;
1210 
1211 	ibuf = repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_TAG].ibuf;
1212 
1213 	err = got_privsep_send_tag_req(ibuf, fd, NULL, -1);
1214 	if (err)
1215 		return err;
1216 
1217 	return got_privsep_recv_tag(tag, ibuf);
1218 }
1219 
1220 static const struct got_error *
1221 read_tag_privsep(struct got_tag_object **tag, int obj_fd,
1222     struct got_repository *repo)
1223 {
1224 	int imsg_fds[2];
1225 	pid_t pid;
1226 	struct imsgbuf *ibuf;
1227 
1228 	if (repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_TAG].imsg_fd != -1)
1229 		return request_tag(tag, repo, obj_fd);
1230 
1231 	ibuf = calloc(1, sizeof(*ibuf));
1232 	if (ibuf == NULL)
1233 		return got_error_from_errno();
1234 
1235 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1)
1236 		return got_error_from_errno();
1237 
1238 	pid = fork();
1239 	if (pid == -1)
1240 		return got_error_from_errno();
1241 	else if (pid == 0) {
1242 		exec_privsep_child(imsg_fds, GOT_PATH_PROG_READ_TAG,
1243 		    repo->path);
1244 		/* not reached */
1245 	}
1246 
1247 	if (close(imsg_fds[1]) != 0)
1248 		return got_error_from_errno();
1249 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_TAG].imsg_fd =
1250 	    imsg_fds[0];
1251 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_TAG].pid = pid;
1252 	imsg_init(ibuf, imsg_fds[0]);
1253 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_TAG].ibuf = ibuf;
1254 
1255 	return request_tag(tag, repo, obj_fd);
1256 }
1257 
1258 static const struct got_error *
1259 open_tag(struct got_tag_object **tag, struct got_repository *repo,
1260     struct got_object_id *id, int check_cache)
1261 {
1262 	const struct got_error *err = NULL;
1263 	struct got_packidx *packidx = NULL;
1264 	int idx;
1265 	char *path_packfile;
1266 
1267 	if (check_cache) {
1268 		*tag = got_repo_get_cached_tag(repo, id);
1269 		if (*tag != NULL) {
1270 			(*tag)->refcnt++;
1271 			return NULL;
1272 		}
1273 	} else
1274 		*tag = NULL;
1275 
1276 	err = got_repo_search_packidx(&packidx, &idx, repo, id);
1277 	if (err == NULL) {
1278 		struct got_pack *pack = NULL;
1279 
1280 		err = get_packfile_path(&path_packfile, packidx);
1281 		if (err)
1282 			return err;
1283 
1284 		pack = got_repo_get_cached_pack(repo, path_packfile);
1285 		if (pack == NULL) {
1286 			err = got_repo_cache_pack(&pack, repo, path_packfile,
1287 			    packidx);
1288 			if (err)
1289 				return err;
1290 		}
1291 		err = read_packed_tag_privsep(tag, pack,
1292 		    packidx, idx, id);
1293 	} else if (err->code == GOT_ERR_NO_OBJ) {
1294 		int fd;
1295 
1296 		err = open_loose_object(&fd, id, repo);
1297 		if (err)
1298 			return err;
1299 		err = read_tag_privsep(tag, fd, repo);
1300 	}
1301 
1302 	if (err == NULL) {
1303 		(*tag)->refcnt++;
1304 		err = got_repo_cache_tag(repo, id, *tag);
1305 	}
1306 
1307 	return err;
1308 }
1309 
1310 const struct got_error *
1311 got_object_open_as_tag(struct got_tag_object **tag,
1312     struct got_repository *repo, struct got_object_id *id)
1313 {
1314 	*tag = got_repo_get_cached_tag(repo, id);
1315 	if (*tag != NULL) {
1316 		(*tag)->refcnt++;
1317 		return NULL;
1318 	}
1319 
1320 	return open_tag(tag, repo, id, 0);
1321 }
1322 
1323 const struct got_error *
1324 got_object_tag_open(struct got_tag_object **tag,
1325     struct got_repository *repo, struct got_object *obj)
1326 {
1327 	return open_tag(tag, repo, got_object_get_id(obj), 1);
1328 }
1329 
1330 int
1331 got_object_tag_get_object_type(struct got_tag_object *tag)
1332 {
1333 	return tag->obj_type;
1334 }
1335 
1336 struct got_object_id *
1337 got_object_tag_get_object_id(struct got_tag_object *tag)
1338 {
1339 	return &tag->id;
1340 }
1341 
1342 static struct got_tree_entry *
1343 find_entry_by_name(struct got_tree_object *tree, const char *name, size_t len)
1344 {
1345 	struct got_tree_entry *te;
1346 
1347 	/* Note that tree entries are sorted in strncmp() order. */
1348 	SIMPLEQ_FOREACH(te, &tree->entries.head, entry) {
1349 		int cmp = strncmp(te->name, name, len);
1350 		if (cmp < 0)
1351 			continue;
1352 		if (cmp > 0)
1353 			break;
1354 		if (te->name[len] == '\0')
1355 			return te;
1356 	}
1357 	return NULL;
1358 }
1359 
1360 const struct got_error *
1361 got_object_id_by_path(struct got_object_id **id, struct got_repository *repo,
1362     struct got_object_id *commit_id, const char *path)
1363 {
1364 	const struct got_error *err = NULL;
1365 	struct got_commit_object *commit = NULL;
1366 	struct got_tree_object *tree = NULL;
1367 	struct got_tree_entry *te = NULL;
1368 	const char *seg, *s;
1369 	size_t seglen;
1370 
1371 	*id = NULL;
1372 
1373 	/* We are expecting an absolute in-repository path. */
1374 	if (path[0] != '/')
1375 		return got_error(GOT_ERR_NOT_ABSPATH);
1376 
1377 	err = got_object_open_as_commit(&commit, repo, commit_id);
1378 	if (err)
1379 		goto done;
1380 
1381 	/* Handle opening of root of commit's tree. */
1382 	if (path[1] == '\0') {
1383 		*id = got_object_id_dup(commit->tree_id);
1384 		if (*id == NULL)
1385 			err = got_error_from_errno();
1386 		goto done;
1387 	}
1388 
1389 	err = got_object_open_as_tree(&tree, repo, commit->tree_id);
1390 	if (err)
1391 		goto done;
1392 
1393 	s = path;
1394 	s++; /* skip leading '/' */
1395 	seg = s;
1396 	seglen = 0;
1397 	while (*s) {
1398 		struct got_tree_object *next_tree;
1399 
1400 		if (*s != '/') {
1401 			s++;
1402 			seglen++;
1403 			if (*s)
1404 				continue;
1405 		}
1406 
1407 		te = find_entry_by_name(tree, seg, seglen);
1408 		if (te == NULL) {
1409 			err = got_error(GOT_ERR_NO_TREE_ENTRY);
1410 			goto done;
1411 		}
1412 
1413 		if (*s == '\0')
1414 			break;
1415 
1416 		seg = s + 1;
1417 		seglen = 0;
1418 		s++;
1419 		if (*s) {
1420 			err = got_object_open_as_tree(&next_tree, repo,
1421 			    te->id);
1422 			te = NULL;
1423 			if (err)
1424 				goto done;
1425 			got_object_tree_close(tree);
1426 			tree = next_tree;
1427 		}
1428 	}
1429 
1430 	if (te) {
1431 		*id = got_object_id_dup(te->id);
1432 		if (*id == NULL)
1433 			return got_error_from_errno();
1434 	} else
1435 		err = got_error(GOT_ERR_NO_TREE_ENTRY);
1436 done:
1437 	if (commit)
1438 		got_object_commit_close(commit);
1439 	if (tree)
1440 		got_object_tree_close(tree);
1441 	return err;
1442 }
1443 
1444 const struct got_error *
1445 got_object_tree_path_changed(int *changed,
1446     struct got_tree_object *tree01, struct got_tree_object *tree02,
1447     const char *path, struct got_repository *repo)
1448 {
1449 	const struct got_error *err = NULL;
1450 	struct got_tree_object *tree1 = NULL, *tree2 = NULL;
1451 	struct got_tree_entry *te1 = NULL, *te2 = NULL;
1452 	const char *seg, *s;
1453 	size_t seglen;
1454 
1455 	*changed = 0;
1456 
1457 	/* We are expecting an absolute in-repository path. */
1458 	if (path[0] != '/')
1459 		return got_error(GOT_ERR_NOT_ABSPATH);
1460 
1461 	/* We not do support comparing the root path. */
1462 	if (path[1] == '\0')
1463 		return got_error(GOT_ERR_BAD_PATH);
1464 
1465 	tree1 = tree01;
1466 	tree2 = tree02;
1467 	s = path;
1468 	s++; /* skip leading '/' */
1469 	seg = s;
1470 	seglen = 0;
1471 	while (*s) {
1472 		struct got_tree_object *next_tree1, *next_tree2;
1473 
1474 		if (*s != '/') {
1475 			s++;
1476 			seglen++;
1477 			if (*s)
1478 				continue;
1479 		}
1480 
1481 		te1 = find_entry_by_name(tree1, seg, seglen);
1482 		if (te1 == NULL) {
1483 			err = got_error(GOT_ERR_NO_OBJ);
1484 			goto done;
1485 		}
1486 
1487 		te2 = find_entry_by_name(tree2, seg, seglen);
1488 		if (te2 == NULL) {
1489 			*changed = 1;
1490 			goto done;
1491 		}
1492 
1493 		if (te1->mode != te2->mode) {
1494 			*changed = 1;
1495 			goto done;
1496 		}
1497 
1498 		if (got_object_id_cmp(te1->id, te2->id) == 0) {
1499 			*changed = 0;
1500 			goto done;
1501 		}
1502 
1503 		if (*s == '\0') { /* final path element */
1504 			*changed = 1;
1505 			goto done;
1506 		}
1507 
1508 		seg = s + 1;
1509 		s++;
1510 		seglen = 0;
1511 		if (*s) {
1512 			err = got_object_open_as_tree(&next_tree1, repo,
1513 			    te1->id);
1514 			te1 = NULL;
1515 			if (err)
1516 				goto done;
1517 			if (tree1 != tree01)
1518 				got_object_tree_close(tree1);
1519 			tree1 = next_tree1;
1520 
1521 			err = got_object_open_as_tree(&next_tree2, repo,
1522 			    te2->id);
1523 			te2 = NULL;
1524 			if (err)
1525 				goto done;
1526 			if (tree2 != tree02)
1527 				got_object_tree_close(tree2);
1528 			tree2 = next_tree2;
1529 		}
1530 	}
1531 done:
1532 	if (tree1 && tree1 != tree01)
1533 		got_object_tree_close(tree1);
1534 	if (tree2 && tree2 != tree02)
1535 		got_object_tree_close(tree2);
1536 	return err;
1537 }