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Date:: Wed Jan 5 20:45:09 2022 UTC
Message:: avoid the creation of new temporary files whenever a packed object is read This speeds up the creation of pack files by about 30%.
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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/uio.h>
20 #include <sys/socket.h>
21 #include <sys/wait.h>
22 #include <sys/resource.h>
23 
24 #include <errno.h>
25 #include <fcntl.h>
26 #include <stdio.h>
27 #include <stdlib.h>
28 #include <string.h>
29 #include <stdint.h>
30 #include <unistd.h>
31 #include <zlib.h>
32 #include <ctype.h>
33 #include <libgen.h>
34 #include <limits.h>
35 #include <time.h>
36 
37 #include "got_compat.h"
38 
39 #include "got_error.h"
40 #include "got_object.h"
41 #include "got_repository.h"
42 #include "got_opentemp.h"
43 #include "got_path.h"
44 
45 #include "got_lib_sha1.h"
46 #include "got_lib_delta.h"
47 #include "got_lib_inflate.h"
48 #include "got_lib_object.h"
49 #include "got_lib_privsep.h"
50 #include "got_lib_object_idcache.h"
51 #include "got_lib_object_cache.h"
52 #include "got_lib_object_parse.h"
53 #include "got_lib_pack.h"
54 #include "got_lib_repository.h"
55 
56 #ifndef MIN
57 #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
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 static const struct got_error *
148 request_packed_object(struct got_object **obj, struct got_pack *pack, int idx,
149     struct got_object_id *id)
150 {
151 	const struct got_error *err = NULL;
152 	struct imsgbuf *ibuf = pack->privsep_child->ibuf;
153 
154 	err = got_privsep_send_packed_obj_req(ibuf, idx, id);
155 	if (err)
156 		return err;
157 
158 	err = got_privsep_recv_obj(obj, ibuf);
159 	if (err)
160 		return err;
161 
162 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
163 
164 	return NULL;
165 }
166 
167 /* Create temporary files used during delta application. */
168 static const struct got_error *
169 pack_child_send_tempfiles(struct imsgbuf *ibuf, struct got_pack *pack)
170 {
171 	const struct got_error *err;
172 	int basefd, accumfd;
173 
174 	/* 
175 	 * For performance reasons, the child will keep reusing the
176 	 * same temporary files during every object request.
177 	 * Opening and closing new files for every object request is
178 	 * too expensive during operations such as 'gotadmin pack'.
179 	 */
180 	if (pack->child_has_tempfiles)
181 		return NULL;
182 
183 	basefd = got_opentempfd();
184 	if (basefd == -1)
185 		return got_error_from_errno("got_opentempfd");
186 
187 	err = got_privsep_send_tmpfd(ibuf, basefd);
188 	if (err)
189 		return err;
190 
191 	accumfd = got_opentempfd();
192 	if (accumfd == -1)
193 		return got_error_from_errno("got_opentempfd");
194 
195 	err = got_privsep_send_tmpfd(ibuf, accumfd);
196 	if (err)
197 		return err;
198 
199 	pack->child_has_tempfiles = 1;
200 	return NULL;
201 }
202 
203 static const struct got_error *
204 request_packed_object_raw(uint8_t **outbuf, off_t *size, size_t *hdrlen,
205     int outfd, struct got_pack *pack, int idx, struct got_object_id *id)
206 {
207 	const struct got_error *err = NULL;
208 	struct imsgbuf *ibuf = pack->privsep_child->ibuf;
209 	int outfd_child;
210 
211 	 err = pack_child_send_tempfiles(ibuf, pack);
212 	 if (err)
213 		return err;
214 
215 	outfd_child = dup(outfd);
216 	if (outfd_child == -1)
217 		return got_error_from_errno("dup");
218 
219 	err = got_privsep_send_packed_raw_obj_req(ibuf, idx, id);
220 	if (err) {
221 		close(outfd_child);
222 		return err;
223 	}
224 
225 	err = got_privsep_send_raw_obj_outfd(ibuf, outfd_child);
226 	if (err)
227 		return err;
228 
229 	err = got_privsep_recv_raw_obj(outbuf, size, hdrlen, ibuf);
230 	if (err)
231 		return err;
232 
233 	return NULL;
234 }
235 
236 static void
237 set_max_datasize(void)
238 {
239 	struct rlimit rl;
240 
241 	if (getrlimit(RLIMIT_DATA, &rl) != 0)
242 		return;
243 
244 	rl.rlim_cur = rl.rlim_max;
245 	setrlimit(RLIMIT_DATA, &rl);
246 }
247 
248 static const struct got_error *
249 start_pack_privsep_child(struct got_pack *pack, struct got_packidx *packidx)
250 {
251 	const struct got_error *err = NULL;
252 	int imsg_fds[2];
253 	pid_t pid;
254 	struct imsgbuf *ibuf;
255 
256 	ibuf = calloc(1, sizeof(*ibuf));
257 	if (ibuf == NULL)
258 		return got_error_from_errno("calloc");
259 
260 	pack->privsep_child = calloc(1, sizeof(*pack->privsep_child));
261 	if (pack->privsep_child == NULL) {
262 		err = got_error_from_errno("calloc");
263 		free(ibuf);
264 		return err;
265 	}
266 	pack->child_has_tempfiles = 0;
267 
268 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1) {
269 		err = got_error_from_errno("socketpair");
270 		goto done;
271 	}
272 
273 	pid = fork();
274 	if (pid == -1) {
275 		err = got_error_from_errno("fork");
276 		goto done;
277 	} else if (pid == 0) {
278 		set_max_datasize();
279 		got_privsep_exec_child(imsg_fds, GOT_PATH_PROG_READ_PACK,
280 		    pack->path_packfile);
281 		/* not reached */
282 	}
283 
284 	if (close(imsg_fds[1]) == -1)
285 		return got_error_from_errno("close");
286 	pack->privsep_child->imsg_fd = imsg_fds[0];
287 	pack->privsep_child->pid = pid;
288 	imsg_init(ibuf, imsg_fds[0]);
289 	pack->privsep_child->ibuf = ibuf;
290 
291 	err = got_privsep_init_pack_child(ibuf, pack, packidx);
292 	if (err) {
293 		const struct got_error *child_err;
294 		err = got_privsep_send_stop(pack->privsep_child->imsg_fd);
295 		child_err = got_privsep_wait_for_child(
296 		    pack->privsep_child->pid);
297 		if (child_err && err == NULL)
298 			err = child_err;
299 	}
300 done:
301 	if (err) {
302 		free(ibuf);
303 		free(pack->privsep_child);
304 		pack->privsep_child = NULL;
305 	}
306 	return err;
307 }
308 
309 static const struct got_error *
310 read_packed_object_privsep(struct got_object **obj,
311     struct got_repository *repo, struct got_pack *pack,
312     struct got_packidx *packidx, int idx, struct got_object_id *id)
313 {
314 	const struct got_error *err = NULL;
315 
316 	if (pack->privsep_child == NULL) {
317 		err = start_pack_privsep_child(pack, packidx);
318 		if (err)
319 			return err;
320 	}
321 
322 	return request_packed_object(obj, pack, idx, id);
323 }
324 
325 static const struct got_error *
326 read_packed_object_raw_privsep(uint8_t **outbuf, off_t *size, size_t *hdrlen,
327     int outfd, struct got_pack *pack, struct got_packidx *packidx, int idx,
328     struct got_object_id *id)
329 {
330 	const struct got_error *err = NULL;
331 
332 	if (pack->privsep_child == NULL) {
333 		err = start_pack_privsep_child(pack, packidx);
334 		if (err)
335 			return err;
336 	}
337 
338 	return request_packed_object_raw(outbuf, size, hdrlen, outfd, pack,
339 	    idx, id);
340 }
341 
342 const struct got_error *
343 got_object_open_packed(struct got_object **obj, struct got_object_id *id,
344     struct got_repository *repo)
345 {
346 	const struct got_error *err = NULL;
347 	struct got_pack *pack = NULL;
348 	struct got_packidx *packidx = NULL;
349 	int idx;
350 	char *path_packfile;
351 
352 	err = got_repo_search_packidx(&packidx, &idx, repo, id);
353 	if (err)
354 		return err;
355 
356 	err = got_packidx_get_packfile_path(&path_packfile,
357 	    packidx->path_packidx);
358 	if (err)
359 		return err;
360 
361 	pack = got_repo_get_cached_pack(repo, path_packfile);
362 	if (pack == NULL) {
363 		err = got_repo_cache_pack(&pack, repo, path_packfile, packidx);
364 		if (err)
365 			goto done;
366 	}
367 
368 	err = read_packed_object_privsep(obj, repo, pack, packidx, idx, id);
369 	if (err)
370 		goto done;
371 done:
372 	free(path_packfile);
373 	return err;
374 }
375 
376 static const struct got_error *
377 request_object(struct got_object **obj, struct got_object_id *id,
378     struct got_repository *repo, int fd)
379 {
380 	const struct got_error *err = NULL;
381 	struct imsgbuf *ibuf;
382 
383 	ibuf = repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_OBJECT].ibuf;
384 
385 	err = got_privsep_send_obj_req(ibuf, fd, id);
386 	if (err)
387 		return err;
388 
389 	return got_privsep_recv_obj(obj, ibuf);
390 }
391 
392 static const struct got_error *
393 request_raw_object(uint8_t **outbuf, off_t *size, size_t *hdrlen, int outfd,
394     struct got_object_id *id, struct got_repository *repo, int infd)
395 {
396 	const struct got_error *err = NULL;
397 	struct imsgbuf *ibuf;
398 	int outfd_child;
399 
400 	ibuf = repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_OBJECT].ibuf;
401 
402 	outfd_child = dup(outfd);
403 	if (outfd_child == -1)
404 		return got_error_from_errno("dup");
405 
406 	err = got_privsep_send_raw_obj_req(ibuf, infd, id);
407 	if (err)
408 		return err;
409 
410 	err = got_privsep_send_raw_obj_outfd(ibuf, outfd_child);
411 	if (err)
412 		return err;
413 
414 	return got_privsep_recv_raw_obj(outbuf, size, hdrlen, ibuf);
415 }
416 
417 static const struct got_error *
418 start_read_object_child(struct got_repository *repo)
419 {
420 	const struct got_error *err = NULL;
421 	int imsg_fds[2];
422 	pid_t pid;
423 	struct imsgbuf *ibuf;
424 
425 	ibuf = calloc(1, sizeof(*ibuf));
426 	if (ibuf == NULL)
427 		return got_error_from_errno("calloc");
428 
429 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1) {
430 		err = got_error_from_errno("socketpair");
431 		free(ibuf);
432 		return err;
433 	}
434 
435 	pid = fork();
436 	if (pid == -1) {
437 		err = got_error_from_errno("fork");
438 		free(ibuf);
439 		return err;
440 	}
441 	else if (pid == 0) {
442 		got_privsep_exec_child(imsg_fds, GOT_PATH_PROG_READ_OBJECT,
443 		    repo->path);
444 		/* not reached */
445 	}
446 
447 	if (close(imsg_fds[1]) == -1) {
448 		err = got_error_from_errno("close");
449 		free(ibuf);
450 		return err;
451 	}
452 
453 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_OBJECT].imsg_fd =
454 	    imsg_fds[0];
455 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_OBJECT].pid = pid;
456 	imsg_init(ibuf, imsg_fds[0]);
457 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_OBJECT].ibuf = ibuf;
458 
459 	return NULL;
460 }
461 
462 const struct got_error *
463 got_object_read_header_privsep(struct got_object **obj,
464     struct got_object_id *id, struct got_repository *repo, int obj_fd)
465 {
466 	const struct got_error *err;
467 
468 	if (repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_OBJECT].imsg_fd != -1)
469 		return request_object(obj, id, repo, obj_fd);
470 
471 	err = start_read_object_child(repo);
472 	if (err) {
473 		close(obj_fd);
474 		return err;
475 	}
476 
477 	return request_object(obj, id, repo, obj_fd);
478 }
479 
480 static const struct got_error *
481 read_object_raw_privsep(uint8_t **outbuf, off_t *size, size_t *hdrlen,
482     int outfd, struct got_object_id *id, struct got_repository *repo,
483     int obj_fd)
484 {
485 	const struct got_error *err;
486 
487 	if (repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_OBJECT].imsg_fd != -1)
488 		return request_raw_object(outbuf, size, hdrlen, outfd, id,
489 		    repo, obj_fd);
490 
491 	err = start_read_object_child(repo);
492 	if (err)
493 		return err;
494 
495 	return request_raw_object(outbuf, size, hdrlen, outfd, id, repo,
496 	    obj_fd);
497 }
498 
499 const struct got_error *
500 got_object_open(struct got_object **obj, struct got_repository *repo,
501     struct got_object_id *id)
502 {
503 	const struct got_error *err = NULL;
504 	int fd;
505 
506 	*obj = got_repo_get_cached_object(repo, id);
507 	if (*obj != NULL) {
508 		(*obj)->refcnt++;
509 		return NULL;
510 	}
511 
512 	err = got_object_open_packed(obj, id, repo);
513 	if (err && err->code != GOT_ERR_NO_OBJ)
514 		return err;
515 	if (*obj) {
516 		(*obj)->refcnt++;
517 		return got_repo_cache_object(repo, id, *obj);
518 	}
519 
520 	err = got_object_open_loose_fd(&fd, id, repo);
521 	if (err) {
522 		if (err->code == GOT_ERR_ERRNO && errno == ENOENT)
523 			err = got_error_no_obj(id);
524 		return err;
525 	}
526 
527 	err = got_object_read_header_privsep(obj, id, repo, fd);
528 	if (err)
529 		return err;
530 
531 	memcpy((*obj)->id.sha1, id->sha1, SHA1_DIGEST_LENGTH);
532 
533 	(*obj)->refcnt++;
534 	return got_repo_cache_object(repo, id, *obj);
535 }
536 
537 /* *outfd must be initialized to -1 by caller */
538 const struct got_error *
539 got_object_raw_open(struct got_raw_object **obj, int *outfd,
540     struct got_repository *repo, struct got_object_id *id)
541 {
542 	const struct got_error *err = NULL;
543 	struct got_packidx *packidx = NULL;
544 	int idx;
545 	uint8_t *outbuf = NULL;
546 	off_t size = 0;
547 	size_t hdrlen = 0;
548 	char *path_packfile = NULL;
549 
550 	*obj = got_repo_get_cached_raw_object(repo, id);
551 	if (*obj != NULL) {
552 		(*obj)->refcnt++;
553 		return NULL;
554 	}
555 
556 	if (*outfd == -1) {
557 		*outfd = got_opentempfd();
558 		if (*outfd == -1)
559 			return got_error_from_errno("got_opentempfd");
560 	}
561 
562 	err = got_repo_search_packidx(&packidx, &idx, repo, id);
563 	if (err == NULL) {
564 		struct got_pack *pack = NULL;
565 
566 		err = got_packidx_get_packfile_path(&path_packfile,
567 		    packidx->path_packidx);
568 		if (err)
569 			goto done;
570 
571 		pack = got_repo_get_cached_pack(repo, path_packfile);
572 		if (pack == NULL) {
573 			err = got_repo_cache_pack(&pack, repo, path_packfile,
574 			    packidx);
575 			if (err)
576 				goto done;
577 		}
578 		err = read_packed_object_raw_privsep(&outbuf, &size, &hdrlen,
579 		    *outfd, pack, packidx, idx, id);
580 		if (err)
581 			goto done;
582 	} else if (err->code == GOT_ERR_NO_OBJ) {
583 		int fd;
584 
585 		err = got_object_open_loose_fd(&fd, id, repo);
586 		if (err)
587 			goto done;
588 		err = read_object_raw_privsep(&outbuf, &size, &hdrlen, *outfd,
589 		    id, repo, fd);
590 		if (err)
591 			goto done;
592 	}
593 
594 	*obj = calloc(1, sizeof(**obj));
595 	if (*obj == NULL) {
596 		err = got_error_from_errno("calloc");
597 		goto done;
598 	}
599 
600 	if (outbuf) {
601 		(*obj)->f = fmemopen(outbuf, hdrlen + size, "r");
602 		if ((*obj)->f == NULL) {
603 			err = got_error_from_errno("fdopen");
604 			goto done;
605 		}
606 		(*obj)->data = outbuf;
607 	} else {
608 		struct stat sb;
609 		if (fstat(*outfd, &sb) == -1) {
610 			err = got_error_from_errno("fstat");
611 			goto done;
612 		}
613 
614 		if (sb.st_size != hdrlen + size) {
615 			err = got_error(GOT_ERR_PRIVSEP_LEN);
616 			goto done;
617 		}
618 
619 		(*obj)->f = fdopen(*outfd, "r");
620 		if ((*obj)->f == NULL) {
621 			err = got_error_from_errno("fdopen");
622 			goto done;
623 		}
624 		(*obj)->data = NULL;
625 		*outfd = -1;
626 	}
627 	(*obj)->hdrlen = hdrlen;
628 	(*obj)->size = size;
629 	err = got_repo_cache_raw_object(repo, id, *obj);
630 done:
631 	free(path_packfile);
632 	if (err) {
633 		if (*obj) {
634 			got_object_raw_close(*obj);
635 			*obj = NULL;
636 		}
637 		free(outbuf);
638 	} else
639 		(*obj)->refcnt++;
640 	return err;
641 }
642 
643 const struct got_error *
644 got_object_open_by_id_str(struct got_object **obj, struct got_repository *repo,
645     const char *id_str)
646 {
647 	struct got_object_id id;
648 
649 	if (!got_parse_sha1_digest(id.sha1, id_str))
650 		return got_error_path(id_str, GOT_ERR_BAD_OBJ_ID_STR);
651 
652 	return got_object_open(obj, repo, &id);
653 }
654 
655 const struct got_error *
656 got_object_resolve_id_str(struct got_object_id **id,
657     struct got_repository *repo, const char *id_str)
658 {
659 	const struct got_error *err = NULL;
660 	struct got_object *obj;
661 
662 	err = got_object_open_by_id_str(&obj, repo, id_str);
663 	if (err)
664 		return err;
665 
666 	*id = got_object_id_dup(got_object_get_id(obj));
667 	got_object_close(obj);
668 	if (*id == NULL)
669 		return got_error_from_errno("got_object_id_dup");
670 
671 	return NULL;
672 }
673 
674 static const struct got_error *
675 request_packed_commit(struct got_commit_object **commit, struct got_pack *pack,
676     int pack_idx, struct got_object_id *id)
677 {
678 	const struct got_error *err = NULL;
679 
680 	err = got_privsep_send_commit_req(pack->privsep_child->ibuf, -1, id,
681 	    pack_idx);
682 	if (err)
683 		return err;
684 
685 	err = got_privsep_recv_commit(commit, pack->privsep_child->ibuf);
686 	if (err)
687 		return err;
688 
689 	(*commit)->flags |= GOT_COMMIT_FLAG_PACKED;
690 	return NULL;
691 }
692 
693 static const struct got_error *
694 read_packed_commit_privsep(struct got_commit_object **commit,
695     struct got_pack *pack, struct got_packidx *packidx, int idx,
696     struct got_object_id *id)
697 {
698 	const struct got_error *err = NULL;
699 
700 	if (pack->privsep_child)
701 		return request_packed_commit(commit, pack, idx, id);
702 
703 	err = start_pack_privsep_child(pack, packidx);
704 	if (err)
705 		return err;
706 
707 	return request_packed_commit(commit, pack, idx, id);
708 }
709 
710 static const struct got_error *
711 request_commit(struct got_commit_object **commit, struct got_repository *repo,
712     int fd, struct got_object_id *id)
713 {
714 	const struct got_error *err = NULL;
715 	struct imsgbuf *ibuf;
716 
717 	ibuf = repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_COMMIT].ibuf;
718 
719 	err = got_privsep_send_commit_req(ibuf, fd, id, -1);
720 	if (err)
721 		return err;
722 
723 	return got_privsep_recv_commit(commit, ibuf);
724 }
725 
726 static const struct got_error *
727 read_commit_privsep(struct got_commit_object **commit, int obj_fd,
728     struct got_object_id *id, struct got_repository *repo)
729 {
730 	const struct got_error *err;
731 	int imsg_fds[2];
732 	pid_t pid;
733 	struct imsgbuf *ibuf;
734 
735 	if (repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_COMMIT].imsg_fd != -1)
736 		return request_commit(commit, repo, obj_fd, id);
737 
738 	ibuf = calloc(1, sizeof(*ibuf));
739 	if (ibuf == NULL)
740 		return got_error_from_errno("calloc");
741 
742 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1) {
743 		err = got_error_from_errno("socketpair");
744 		free(ibuf);
745 		return err;
746 	}
747 
748 	pid = fork();
749 	if (pid == -1) {
750 		err = got_error_from_errno("fork");
751 		free(ibuf);
752 		return err;
753 	}
754 	else if (pid == 0) {
755 		got_privsep_exec_child(imsg_fds, GOT_PATH_PROG_READ_COMMIT,
756 		    repo->path);
757 		/* not reached */
758 	}
759 
760 	if (close(imsg_fds[1]) == -1) {
761 		err = got_error_from_errno("close");
762 		free(ibuf);
763 		return err;
764 	}
765 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_COMMIT].imsg_fd =
766 	    imsg_fds[0];
767 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_COMMIT].pid = pid;
768 	imsg_init(ibuf, imsg_fds[0]);
769 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_COMMIT].ibuf = ibuf;
770 
771 	return request_commit(commit, repo, obj_fd, id);
772 }
773 
774 
775 static const struct got_error *
776 open_commit(struct got_commit_object **commit,
777     struct got_repository *repo, struct got_object_id *id, int check_cache)
778 {
779 	const struct got_error *err = NULL;
780 	struct got_packidx *packidx = NULL;
781 	int idx;
782 	char *path_packfile = NULL;
783 
784 	if (check_cache) {
785 		*commit = got_repo_get_cached_commit(repo, id);
786 		if (*commit != NULL) {
787 			(*commit)->refcnt++;
788 			return NULL;
789 		}
790 	} else
791 		*commit = NULL;
792 
793 	err = got_repo_search_packidx(&packidx, &idx, repo, id);
794 	if (err == NULL) {
795 		struct got_pack *pack = NULL;
796 
797 		err = got_packidx_get_packfile_path(&path_packfile,
798 		    packidx->path_packidx);
799 		if (err)
800 			return err;
801 
802 		pack = got_repo_get_cached_pack(repo, path_packfile);
803 		if (pack == NULL) {
804 			err = got_repo_cache_pack(&pack, repo, path_packfile,
805 			    packidx);
806 			if (err)
807 				goto done;
808 		}
809 		err = read_packed_commit_privsep(commit, pack,
810 		    packidx, idx, id);
811 	} else if (err->code == GOT_ERR_NO_OBJ) {
812 		int fd;
813 
814 		err = got_object_open_loose_fd(&fd, id, repo);
815 		if (err)
816 			return err;
817 		err = read_commit_privsep(commit, fd, id, repo);
818 	}
819 
820 	if (err == NULL) {
821 		(*commit)->refcnt++;
822 		err = got_repo_cache_commit(repo, id, *commit);
823 	}
824 done:
825 	free(path_packfile);
826 	return err;
827 }
828 
829 const struct got_error *
830 got_object_open_as_commit(struct got_commit_object **commit,
831     struct got_repository *repo, struct got_object_id *id)
832 {
833 	*commit = got_repo_get_cached_commit(repo, id);
834 	if (*commit != NULL) {
835 		(*commit)->refcnt++;
836 		return NULL;
837 	}
838 
839 	return open_commit(commit, repo, id, 0);
840 }
841 
842 const struct got_error *
843 got_object_commit_open(struct got_commit_object **commit,
844     struct got_repository *repo, struct got_object *obj)
845 {
846 	return open_commit(commit, repo, got_object_get_id(obj), 1);
847 }
848 
849 const struct got_error *
850 got_object_qid_alloc(struct got_object_qid **qid, struct got_object_id *id)
851 {
852 	const struct got_error *err = NULL;
853 
854 	*qid = calloc(1, sizeof(**qid));
855 	if (*qid == NULL)
856 		return got_error_from_errno("calloc");
857 
858 	(*qid)->id = got_object_id_dup(id);
859 	if ((*qid)->id == NULL) {
860 		err = got_error_from_errno("got_object_id_dup");
861 		got_object_qid_free(*qid);
862 		*qid = NULL;
863 		return err;
864 	}
865 
866 	return NULL;
867 }
868 
869 const struct got_error *
870 got_object_id_queue_copy(const struct got_object_id_queue *src,
871     struct got_object_id_queue *dest)
872 {
873 	const struct got_error *err;
874 	struct got_object_qid *qid;
875 
876 	STAILQ_FOREACH(qid, src, entry) {
877 		struct got_object_qid *new;
878 		/*
879 		 * Deep-copy the object ID only. Let the caller deal
880 		 * with setting up the new->data pointer if needed.
881 		 */
882 		err = got_object_qid_alloc(&new, qid->id); 
883 		if (err) {
884 			got_object_id_queue_free(dest);
885 			return err;
886 		}
887 		STAILQ_INSERT_TAIL(dest, new, entry);
888 	}
889 
890 	return NULL;
891 }
892 
893 static const struct got_error *
894 request_packed_tree(struct got_tree_object **tree, struct got_pack *pack,
895     int pack_idx, struct got_object_id *id)
896 {
897 	const struct got_error *err = NULL;
898 
899 	err = got_privsep_send_tree_req(pack->privsep_child->ibuf, -1, id,
900 	    pack_idx);
901 	if (err)
902 		return err;
903 
904 	return got_privsep_recv_tree(tree, pack->privsep_child->ibuf);
905 }
906 
907 static const struct got_error *
908 read_packed_tree_privsep(struct got_tree_object **tree,
909     struct got_pack *pack, struct got_packidx *packidx, int idx,
910     struct got_object_id *id)
911 {
912 	const struct got_error *err = NULL;
913 
914 	if (pack->privsep_child)
915 		return request_packed_tree(tree, pack, idx, id);
916 
917 	err = start_pack_privsep_child(pack, packidx);
918 	if (err)
919 		return err;
920 
921 	return request_packed_tree(tree, pack, idx, id);
922 }
923 
924 static const struct got_error *
925 request_tree(struct got_tree_object **tree, struct got_repository *repo,
926     int fd, struct got_object_id *id)
927 {
928 	const struct got_error *err = NULL;
929 	struct imsgbuf *ibuf;
930 
931 	ibuf = repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_TREE].ibuf;
932 
933 	err = got_privsep_send_tree_req(ibuf, fd, id, -1);
934 	if (err)
935 		return err;
936 
937 	return got_privsep_recv_tree(tree, ibuf);
938 }
939 
940 const struct got_error *
941 read_tree_privsep(struct got_tree_object **tree, int obj_fd,
942     struct got_object_id *id, struct got_repository *repo)
943 {
944 	const struct got_error *err;
945 	int imsg_fds[2];
946 	pid_t pid;
947 	struct imsgbuf *ibuf;
948 
949 	if (repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_TREE].imsg_fd != -1)
950 		return request_tree(tree, repo, obj_fd, id);
951 
952 	ibuf = calloc(1, sizeof(*ibuf));
953 	if (ibuf == NULL)
954 		return got_error_from_errno("calloc");
955 
956 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1) {
957 		err = got_error_from_errno("socketpair");
958 		free(ibuf);
959 		return err;
960 	}
961 
962 	pid = fork();
963 	if (pid == -1) {
964 		err = got_error_from_errno("fork");
965 		free(ibuf);
966 		return err;
967 	}
968 	else if (pid == 0) {
969 		got_privsep_exec_child(imsg_fds, GOT_PATH_PROG_READ_TREE,
970 		    repo->path);
971 		/* not reached */
972 	}
973 
974 	if (close(imsg_fds[1]) == -1) {
975 		err = got_error_from_errno("close");
976 		free(ibuf);
977 		return err;
978 	}
979 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_TREE].imsg_fd =
980 	    imsg_fds[0];
981 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_TREE].pid = pid;
982 	imsg_init(ibuf, imsg_fds[0]);
983 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_TREE].ibuf = ibuf;
984 
985 
986 	return request_tree(tree, repo, obj_fd, id);
987 }
988 
989 static const struct got_error *
990 open_tree(struct got_tree_object **tree, struct got_repository *repo,
991     struct got_object_id *id, int check_cache)
992 {
993 	const struct got_error *err = NULL;
994 	struct got_packidx *packidx = NULL;
995 	int idx;
996 	char *path_packfile = NULL;
997 
998 	if (check_cache) {
999 		*tree = got_repo_get_cached_tree(repo, id);
1000 		if (*tree != NULL) {
1001 			(*tree)->refcnt++;
1002 			return NULL;
1003 		}
1004 	} else
1005 		*tree = NULL;
1006 
1007 	err = got_repo_search_packidx(&packidx, &idx, repo, id);
1008 	if (err == NULL) {
1009 		struct got_pack *pack = NULL;
1010 
1011 		err = got_packidx_get_packfile_path(&path_packfile,
1012 		    packidx->path_packidx);
1013 		if (err)
1014 			return err;
1015 
1016 		pack = got_repo_get_cached_pack(repo, path_packfile);
1017 		if (pack == NULL) {
1018 			err = got_repo_cache_pack(&pack, repo, path_packfile,
1019 			    packidx);
1020 			if (err)
1021 				goto done;
1022 		}
1023 		err = read_packed_tree_privsep(tree, pack,
1024 		    packidx, idx, id);
1025 	} else if (err->code == GOT_ERR_NO_OBJ) {
1026 		int fd;
1027 
1028 		err = got_object_open_loose_fd(&fd, id, repo);
1029 		if (err)
1030 			return err;
1031 		err = read_tree_privsep(tree, fd, id, repo);
1032 	}
1033 
1034 	if (err == NULL) {
1035 		(*tree)->refcnt++;
1036 		err = got_repo_cache_tree(repo, id, *tree);
1037 	}
1038 done:
1039 	free(path_packfile);
1040 	return err;
1041 }
1042 
1043 const struct got_error *
1044 got_object_open_as_tree(struct got_tree_object **tree,
1045     struct got_repository *repo, struct got_object_id *id)
1046 {
1047 	*tree = got_repo_get_cached_tree(repo, id);
1048 	if (*tree != NULL) {
1049 		(*tree)->refcnt++;
1050 		return NULL;
1051 	}
1052 
1053 	return open_tree(tree, repo, id, 0);
1054 }
1055 
1056 const struct got_error *
1057 got_object_tree_open(struct got_tree_object **tree,
1058     struct got_repository *repo, struct got_object *obj)
1059 {
1060 	return open_tree(tree, repo, got_object_get_id(obj), 1);
1061 }
1062 
1063 int
1064 got_object_tree_get_nentries(struct got_tree_object *tree)
1065 {
1066 	return tree->nentries;
1067 }
1068 
1069 struct got_tree_entry *
1070 got_object_tree_get_first_entry(struct got_tree_object *tree)
1071 {
1072 	return got_object_tree_get_entry(tree, 0);
1073 }
1074 
1075 struct got_tree_entry *
1076 got_object_tree_get_last_entry(struct got_tree_object *tree)
1077 {
1078 	return got_object_tree_get_entry(tree, tree->nentries - 1);
1079 }
1080 
1081 struct got_tree_entry *
1082 got_object_tree_get_entry(struct got_tree_object *tree, int i)
1083 {
1084 	if (i < 0 || i >= tree->nentries)
1085 		return NULL;
1086 	return &tree->entries[i];
1087 }
1088 
1089 mode_t
1090 got_tree_entry_get_mode(struct got_tree_entry *te)
1091 {
1092 	return te->mode;
1093 }
1094 
1095 const char *
1096 got_tree_entry_get_name(struct got_tree_entry *te)
1097 {
1098 	return &te->name[0];
1099 }
1100 
1101 struct got_object_id *
1102 got_tree_entry_get_id(struct got_tree_entry *te)
1103 {
1104 	return &te->id;
1105 }
1106 
1107 const struct got_error *
1108 got_object_blob_read_to_str(char **s, struct got_blob_object *blob)
1109 {
1110 	const struct got_error *err = NULL;
1111 	size_t len, totlen, hdrlen, offset;
1112 
1113 	*s = NULL;
1114 
1115 	hdrlen = got_object_blob_get_hdrlen(blob);
1116 	totlen = 0;
1117 	offset = 0;
1118 	do {
1119 		char *p;
1120 
1121 		err = got_object_blob_read_block(&len, blob);
1122 		if (err)
1123 			return err;
1124 
1125 		if (len == 0)
1126 			break;
1127 
1128 		totlen += len - hdrlen;
1129 		p = realloc(*s, totlen + 1);
1130 		if (p == NULL) {
1131 			err = got_error_from_errno("realloc");
1132 			free(*s);
1133 			*s = NULL;
1134 			return err;
1135 		}
1136 		*s = p;
1137 		/* Skip blob object header first time around. */
1138 		memcpy(*s + offset,
1139 		    got_object_blob_get_read_buf(blob) + hdrlen, len - hdrlen);
1140 		hdrlen = 0;
1141 		offset = totlen;
1142 	} while (len > 0);
1143 
1144 	(*s)[totlen] = '\0';
1145 	return NULL;
1146 }
1147 
1148 const struct got_error *
1149 got_tree_entry_get_symlink_target(char **link_target, struct got_tree_entry *te,
1150     struct got_repository *repo)
1151 {
1152 	const struct got_error *err = NULL;
1153 	struct got_blob_object *blob = NULL;
1154 
1155 	*link_target = NULL;
1156 
1157 	if (!got_object_tree_entry_is_symlink(te))
1158 		return got_error(GOT_ERR_TREE_ENTRY_TYPE);
1159 
1160 	err = got_object_open_as_blob(&blob, repo,
1161 	    got_tree_entry_get_id(te), PATH_MAX);
1162 	if (err)
1163 		return err;
1164 
1165 	err = got_object_blob_read_to_str(link_target, blob);
1166 	got_object_blob_close(blob);
1167 	if (err) {
1168 		free(*link_target);
1169 		*link_target = NULL;
1170 	}
1171 	return err;
1172 }
1173 
1174 int
1175 got_tree_entry_get_index(struct got_tree_entry *te)
1176 {
1177 	return te->idx;
1178 }
1179 
1180 struct got_tree_entry *
1181 got_tree_entry_get_next(struct got_tree_object *tree,
1182     struct got_tree_entry *te)
1183 {
1184 	return got_object_tree_get_entry(tree, te->idx + 1);
1185 }
1186 
1187 struct got_tree_entry *
1188 got_tree_entry_get_prev(struct got_tree_object *tree,
1189     struct got_tree_entry *te)
1190 {
1191 	return got_object_tree_get_entry(tree, te->idx - 1);
1192 }
1193 
1194 static const struct got_error *
1195 request_packed_blob(uint8_t **outbuf, size_t *size, size_t *hdrlen, int outfd,
1196     struct got_pack *pack, struct got_packidx *packidx, int idx,
1197     struct got_object_id *id)
1198 {
1199 	const struct got_error *err = NULL;
1200 	struct imsgbuf *ibuf = pack->privsep_child->ibuf;
1201 	int outfd_child;
1202 
1203 	 err = pack_child_send_tempfiles(ibuf, pack);
1204 	 if (err)
1205 		return err;
1206 
1207 	outfd_child = dup(outfd);
1208 	if (outfd_child == -1)
1209 		return got_error_from_errno("dup");
1210 
1211 	err = got_privsep_send_blob_req(pack->privsep_child->ibuf, -1, id, idx);
1212 	if (err)
1213 		return err;
1214 
1215 	err = got_privsep_send_blob_outfd(pack->privsep_child->ibuf,
1216 	    outfd_child);
1217 	if (err) {
1218 		return err;
1219 	}
1220 
1221 	err = got_privsep_recv_blob(outbuf, size, hdrlen,
1222 	    pack->privsep_child->ibuf);
1223 	if (err)
1224 		return err;
1225 
1226 	if (lseek(outfd, SEEK_SET, 0) == -1)
1227 		err = got_error_from_errno("lseek");
1228 
1229 	return err;
1230 }
1231 
1232 static const struct got_error *
1233 read_packed_blob_privsep(uint8_t **outbuf, size_t *size, size_t *hdrlen,
1234     int outfd, struct got_pack *pack, struct got_packidx *packidx, int idx,
1235     struct got_object_id *id)
1236 {
1237 	const struct got_error *err = NULL;
1238 
1239 	if (pack->privsep_child == NULL) {
1240 		err = start_pack_privsep_child(pack, packidx);
1241 		if (err)
1242 			return err;
1243 	}
1244 
1245 	return request_packed_blob(outbuf, size, hdrlen, outfd, pack, packidx,
1246 	    idx, id);
1247 }
1248 
1249 static const struct got_error *
1250 request_blob(uint8_t **outbuf, size_t *size, size_t *hdrlen, int outfd,
1251     int infd, struct got_object_id *id, struct imsgbuf *ibuf)
1252 {
1253 	const struct got_error *err = NULL;
1254 	int outfd_child;
1255 
1256 	outfd_child = dup(outfd);
1257 	if (outfd_child == -1)
1258 		return got_error_from_errno("dup");
1259 
1260 	err = got_privsep_send_blob_req(ibuf, infd, id, -1);
1261 	if (err)
1262 		return err;
1263 
1264 	err = got_privsep_send_blob_outfd(ibuf, outfd_child);
1265 	if (err)
1266 		return err;
1267 
1268 	err = got_privsep_recv_blob(outbuf, size, hdrlen, ibuf);
1269 	if (err)
1270 		return err;
1271 
1272 	if (lseek(outfd, SEEK_SET, 0) == -1)
1273 		return got_error_from_errno("lseek");
1274 
1275 	return err;
1276 }
1277 
1278 static const struct got_error *
1279 read_blob_privsep(uint8_t **outbuf, size_t *size, size_t *hdrlen,
1280     int outfd, int infd, struct got_object_id *id, struct got_repository *repo)
1281 {
1282 	const struct got_error *err;
1283 	int imsg_fds[2];
1284 	pid_t pid;
1285 	struct imsgbuf *ibuf;
1286 
1287 	if (repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_BLOB].imsg_fd != -1) {
1288 		ibuf = repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_BLOB].ibuf;
1289 		return request_blob(outbuf, size, hdrlen, outfd, infd, id,
1290 		    ibuf);
1291 	}
1292 
1293 	ibuf = calloc(1, sizeof(*ibuf));
1294 	if (ibuf == NULL)
1295 		return got_error_from_errno("calloc");
1296 
1297 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1) {
1298 		err = got_error_from_errno("socketpair");
1299 		free(ibuf);
1300 		return err;
1301 	}
1302 
1303 	pid = fork();
1304 	if (pid == -1) {
1305 		err = got_error_from_errno("fork");
1306 		free(ibuf);
1307 		return err;
1308 	}
1309 	else if (pid == 0) {
1310 		got_privsep_exec_child(imsg_fds, GOT_PATH_PROG_READ_BLOB,
1311 		    repo->path);
1312 		/* not reached */
1313 	}
1314 
1315 	if (close(imsg_fds[1]) == -1) {
1316 		err = got_error_from_errno("close");
1317 		free(ibuf);
1318 		return err;
1319 	}
1320 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_BLOB].imsg_fd =
1321 	    imsg_fds[0];
1322 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_BLOB].pid = pid;
1323 	imsg_init(ibuf, imsg_fds[0]);
1324 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_BLOB].ibuf = ibuf;
1325 
1326 	return request_blob(outbuf, size, hdrlen, outfd, infd, id, ibuf);
1327 }
1328 
1329 static const struct got_error *
1330 open_blob(struct got_blob_object **blob, struct got_repository *repo,
1331     struct got_object_id *id, size_t blocksize)
1332 {
1333 	const struct got_error *err = NULL;
1334 	struct got_packidx *packidx = NULL;
1335 	int idx;
1336 	char *path_packfile = NULL;
1337 	uint8_t *outbuf;
1338 	int outfd;
1339 	size_t size, hdrlen;
1340 	struct stat sb;
1341 
1342 	*blob = calloc(1, sizeof(**blob));
1343 	if (*blob == NULL)
1344 		return got_error_from_errno("calloc");
1345 
1346 	outfd = got_opentempfd();
1347 	if (outfd == -1)
1348 		return got_error_from_errno("got_opentempfd");
1349 
1350 	(*blob)->read_buf = malloc(blocksize);
1351 	if ((*blob)->read_buf == NULL) {
1352 		err = got_error_from_errno("malloc");
1353 		goto done;
1354 	}
1355 
1356 	err = got_repo_search_packidx(&packidx, &idx, repo, id);
1357 	if (err == NULL) {
1358 		struct got_pack *pack = NULL;
1359 
1360 		err = got_packidx_get_packfile_path(&path_packfile,
1361 		    packidx->path_packidx);
1362 		if (err)
1363 			goto done;
1364 
1365 		pack = got_repo_get_cached_pack(repo, path_packfile);
1366 		if (pack == NULL) {
1367 			err = got_repo_cache_pack(&pack, repo, path_packfile,
1368 			    packidx);
1369 			if (err)
1370 				goto done;
1371 		}
1372 		err = read_packed_blob_privsep(&outbuf, &size, &hdrlen, outfd,
1373 		    pack, packidx, idx, id);
1374 	} else if (err->code == GOT_ERR_NO_OBJ) {
1375 		int infd;
1376 
1377 		err = got_object_open_loose_fd(&infd, id, repo);
1378 		if (err)
1379 			goto done;
1380 		err = read_blob_privsep(&outbuf, &size, &hdrlen, outfd, infd,
1381 		    id, repo);
1382 	}
1383 	if (err)
1384 		goto done;
1385 
1386 	if (hdrlen > size) {
1387 		err = got_error(GOT_ERR_BAD_OBJ_HDR);
1388 		goto done;
1389 	}
1390 
1391 	if (outbuf) {
1392 		if (close(outfd) == -1 && err == NULL)
1393 			err = got_error_from_errno("close");
1394 		outfd = -1;
1395 		(*blob)->f = fmemopen(outbuf, size, "rb");
1396 		if ((*blob)->f == NULL) {
1397 			err = got_error_from_errno("fmemopen");
1398 			free(outbuf);
1399 			goto done;
1400 		}
1401 		(*blob)->data = outbuf;
1402 	} else {
1403 		if (fstat(outfd, &sb) == -1) {
1404 			err = got_error_from_errno("fstat");
1405 			goto done;
1406 		}
1407 
1408 		if (sb.st_size != size) {
1409 			err = got_error(GOT_ERR_PRIVSEP_LEN);
1410 			goto done;
1411 		}
1412 
1413 		(*blob)->f = fdopen(outfd, "rb");
1414 		if ((*blob)->f == NULL) {
1415 			err = got_error_from_errno("fdopen");
1416 			close(outfd);
1417 			outfd = -1;
1418 			goto done;
1419 		}
1420 	}
1421 
1422 	(*blob)->hdrlen = hdrlen;
1423 	(*blob)->blocksize = blocksize;
1424 	memcpy(&(*blob)->id.sha1, id->sha1, SHA1_DIGEST_LENGTH);
1425 
1426 done:
1427 	free(path_packfile);
1428 	if (err) {
1429 		if (*blob) {
1430 			got_object_blob_close(*blob);
1431 			*blob = NULL;
1432 		} else if (outfd != -1)
1433 			close(outfd);
1434 	}
1435 	return err;
1436 }
1437 
1438 const struct got_error *
1439 got_object_open_as_blob(struct got_blob_object **blob,
1440     struct got_repository *repo, struct got_object_id *id,
1441     size_t blocksize)
1442 {
1443 	return open_blob(blob, repo, id, blocksize);
1444 }
1445 
1446 const struct got_error *
1447 got_object_blob_open(struct got_blob_object **blob,
1448     struct got_repository *repo, struct got_object *obj, size_t blocksize)
1449 {
1450 	return open_blob(blob, repo, got_object_get_id(obj), blocksize);
1451 }
1452 
1453 const struct got_error *
1454 got_object_blob_close(struct got_blob_object *blob)
1455 {
1456 	const struct got_error *err = NULL;
1457 	free(blob->read_buf);
1458 	if (blob->f && fclose(blob->f) == EOF)
1459 		err = got_error_from_errno("fclose");
1460 	free(blob->data);
1461 	free(blob);
1462 	return err;
1463 }
1464 
1465 void
1466 got_object_blob_rewind(struct got_blob_object *blob)
1467 {
1468 	if (blob->f)
1469 		rewind(blob->f);
1470 }
1471 
1472 char *
1473 got_object_blob_id_str(struct got_blob_object *blob, char *buf, size_t size)
1474 {
1475 	return got_sha1_digest_to_str(blob->id.sha1, buf, size);
1476 }
1477 
1478 size_t
1479 got_object_blob_get_hdrlen(struct got_blob_object *blob)
1480 {
1481 	return blob->hdrlen;
1482 }
1483 
1484 const uint8_t *
1485 got_object_blob_get_read_buf(struct got_blob_object *blob)
1486 {
1487 	return blob->read_buf;
1488 }
1489 
1490 const struct got_error *
1491 got_object_blob_read_block(size_t *outlenp, struct got_blob_object *blob)
1492 {
1493 	size_t n;
1494 
1495 	n = fread(blob->read_buf, 1, blob->blocksize, blob->f);
1496 	if (n == 0 && ferror(blob->f))
1497 		return got_ferror(blob->f, GOT_ERR_IO);
1498 	*outlenp = n;
1499 	return NULL;
1500 }
1501 
1502 const struct got_error *
1503 got_object_blob_dump_to_file(off_t *filesize, int *nlines,
1504     off_t **line_offsets, FILE *outfile, struct got_blob_object *blob)
1505 {
1506 	const struct got_error *err = NULL;
1507 	size_t n, len, hdrlen;
1508 	const uint8_t *buf;
1509 	int i;
1510 	const int alloc_chunksz = 512;
1511 	size_t nalloc = 0;
1512 	off_t off = 0, total_len = 0;
1513 
1514 	if (line_offsets)
1515 		*line_offsets = NULL;
1516 	if (filesize)
1517 		*filesize = 0;
1518 	if (nlines)
1519 		*nlines = 0;
1520 
1521 	hdrlen = got_object_blob_get_hdrlen(blob);
1522 	do {
1523 		err = got_object_blob_read_block(&len, blob);
1524 		if (err)
1525 			return err;
1526 		if (len == 0)
1527 			break;
1528 		buf = got_object_blob_get_read_buf(blob);
1529 		i = hdrlen;
1530 		if (nlines) {
1531 			if (line_offsets && *line_offsets == NULL) {
1532 				/* Have some data but perhaps no '\n'. */
1533 				*nlines = 1;
1534 				nalloc = alloc_chunksz;
1535 				*line_offsets = calloc(nalloc,
1536 				    sizeof(**line_offsets));
1537 				if (*line_offsets == NULL)
1538 					return got_error_from_errno("calloc");
1539 
1540 				/* Skip forward over end of first line. */
1541 				while (i < len) {
1542 					if (buf[i] == '\n')
1543 						break;
1544 					i++;
1545 				}
1546 			}
1547 			/* Scan '\n' offsets in remaining chunk of data. */
1548 			while (i < len) {
1549 				if (buf[i] != '\n') {
1550 					i++;
1551 					continue;
1552 				}
1553 				(*nlines)++;
1554 				if (line_offsets && nalloc < *nlines) {
1555 					size_t n = *nlines + alloc_chunksz;
1556 					off_t *o = recallocarray(*line_offsets,
1557 					    nalloc, n, sizeof(**line_offsets));
1558 					if (o == NULL) {
1559 						free(*line_offsets);
1560 						*line_offsets = NULL;
1561 						return got_error_from_errno(
1562 						    "recallocarray");
1563 					}
1564 					*line_offsets = o;
1565 					nalloc = n;
1566 				}
1567 				if (line_offsets) {
1568 					off = total_len + i - hdrlen + 1;
1569 					(*line_offsets)[*nlines - 1] = off;
1570 				}
1571 				i++;
1572 			}
1573 		}
1574 		/* Skip blob object header first time around. */
1575 		n = fwrite(buf + hdrlen, 1, len - hdrlen, outfile);
1576 		if (n != len - hdrlen)
1577 			return got_ferror(outfile, GOT_ERR_IO);
1578 		total_len += len - hdrlen;
1579 		hdrlen = 0;
1580 	} while (len != 0);
1581 
1582 	if (fflush(outfile) != 0)
1583 		return got_error_from_errno("fflush");
1584 	rewind(outfile);
1585 
1586 	if (filesize)
1587 		*filesize = total_len;
1588 
1589 	return NULL;
1590 }
1591 
1592 static const struct got_error *
1593 request_packed_tag(struct got_tag_object **tag, struct got_pack *pack,
1594     int pack_idx, struct got_object_id *id)
1595 {
1596 	const struct got_error *err = NULL;
1597 
1598 	err = got_privsep_send_tag_req(pack->privsep_child->ibuf, -1, id,
1599 	    pack_idx);
1600 	if (err)
1601 		return err;
1602 
1603 	return got_privsep_recv_tag(tag, pack->privsep_child->ibuf);
1604 }
1605 
1606 static const struct got_error *
1607 read_packed_tag_privsep(struct got_tag_object **tag,
1608     struct got_pack *pack, struct got_packidx *packidx, int idx,
1609     struct got_object_id *id)
1610 {
1611 	const struct got_error *err = NULL;
1612 
1613 	if (pack->privsep_child)
1614 		return request_packed_tag(tag, pack, idx, id);
1615 
1616 	err = start_pack_privsep_child(pack, packidx);
1617 	if (err)
1618 		return err;
1619 
1620 	return request_packed_tag(tag, pack, idx, id);
1621 }
1622 
1623 static const struct got_error *
1624 request_tag(struct got_tag_object **tag, struct got_repository *repo,
1625     int fd, struct got_object_id *id)
1626 {
1627 	const struct got_error *err = NULL;
1628 	struct imsgbuf *ibuf;
1629 
1630 	ibuf = repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_TAG].ibuf;
1631 
1632 	err = got_privsep_send_tag_req(ibuf, fd, id, -1);
1633 	if (err)
1634 		return err;
1635 
1636 	return got_privsep_recv_tag(tag, ibuf);
1637 }
1638 
1639 static const struct got_error *
1640 read_tag_privsep(struct got_tag_object **tag, int obj_fd,
1641     struct got_object_id *id, struct got_repository *repo)
1642 {
1643 	const struct got_error *err;
1644 	int imsg_fds[2];
1645 	pid_t pid;
1646 	struct imsgbuf *ibuf;
1647 
1648 	if (repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_TAG].imsg_fd != -1)
1649 		return request_tag(tag, repo, obj_fd, id);
1650 
1651 	ibuf = calloc(1, sizeof(*ibuf));
1652 	if (ibuf == NULL)
1653 		return got_error_from_errno("calloc");
1654 
1655 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1) {
1656 		err = got_error_from_errno("socketpair");
1657 		free(ibuf);
1658 		return err;
1659 	}
1660 
1661 	pid = fork();
1662 	if (pid == -1) {
1663 		err = got_error_from_errno("fork");
1664 		free(ibuf);
1665 		return err;
1666 	}
1667 	else if (pid == 0) {
1668 		got_privsep_exec_child(imsg_fds, GOT_PATH_PROG_READ_TAG,
1669 		    repo->path);
1670 		/* not reached */
1671 	}
1672 
1673 	if (close(imsg_fds[1]) == -1) {
1674 		err = got_error_from_errno("close");
1675 		free(ibuf);
1676 		return err;
1677 	}
1678 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_TAG].imsg_fd =
1679 	    imsg_fds[0];
1680 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_TAG].pid = pid;
1681 	imsg_init(ibuf, imsg_fds[0]);
1682 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_TAG].ibuf = ibuf;
1683 
1684 	return request_tag(tag, repo, obj_fd, id);
1685 }
1686 
1687 static const struct got_error *
1688 open_tag(struct got_tag_object **tag, struct got_repository *repo,
1689     struct got_object_id *id, int check_cache)
1690 {
1691 	const struct got_error *err = NULL;
1692 	struct got_packidx *packidx = NULL;
1693 	int idx;
1694 	char *path_packfile = NULL;
1695 	struct got_object *obj = NULL;
1696 	int obj_type = GOT_OBJ_TYPE_ANY;
1697 
1698 	if (check_cache) {
1699 		*tag = got_repo_get_cached_tag(repo, id);
1700 		if (*tag != NULL) {
1701 			(*tag)->refcnt++;
1702 			return NULL;
1703 		}
1704 	} else
1705 		*tag = NULL;
1706 
1707 	err = got_repo_search_packidx(&packidx, &idx, repo, id);
1708 	if (err == NULL) {
1709 		struct got_pack *pack = NULL;
1710 
1711 		err = got_packidx_get_packfile_path(&path_packfile,
1712 		    packidx->path_packidx);
1713 		if (err)
1714 			return err;
1715 
1716 		pack = got_repo_get_cached_pack(repo, path_packfile);
1717 		if (pack == NULL) {
1718 			err = got_repo_cache_pack(&pack, repo, path_packfile,
1719 			    packidx);
1720 			if (err)
1721 				goto done;
1722 		}
1723 
1724 		/* Beware of "lightweight" tags: Check object type first. */
1725 		err = read_packed_object_privsep(&obj, repo, pack, packidx,
1726 		    idx, id);
1727 		if (err)
1728 			goto done;
1729 		obj_type = obj->type;
1730 		got_object_close(obj);
1731 		if (obj_type != GOT_OBJ_TYPE_TAG) {
1732 			err = got_error(GOT_ERR_OBJ_TYPE);
1733 			goto done;
1734 		}
1735 		err = read_packed_tag_privsep(tag, pack, packidx, idx, id);
1736 	} else if (err->code == GOT_ERR_NO_OBJ) {
1737 		int fd;
1738 
1739 		err = got_object_open_loose_fd(&fd, id, repo);
1740 		if (err)
1741 			return err;
1742 		err = got_object_read_header_privsep(&obj, id, repo, fd);
1743 		if (err)
1744 			return err;
1745 		obj_type = obj->type;
1746 		got_object_close(obj);
1747 		if (obj_type != GOT_OBJ_TYPE_TAG)
1748 			return got_error(GOT_ERR_OBJ_TYPE);
1749 
1750 		err = got_object_open_loose_fd(&fd, id, repo);
1751 		if (err)
1752 			return err;
1753 		err = read_tag_privsep(tag, fd, id, repo);
1754 	}
1755 
1756 	if (err == NULL) {
1757 		(*tag)->refcnt++;
1758 		err = got_repo_cache_tag(repo, id, *tag);
1759 	}
1760 done:
1761 	free(path_packfile);
1762 	return err;
1763 }
1764 
1765 const struct got_error *
1766 got_object_open_as_tag(struct got_tag_object **tag,
1767     struct got_repository *repo, struct got_object_id *id)
1768 {
1769 	*tag = got_repo_get_cached_tag(repo, id);
1770 	if (*tag != NULL) {
1771 		(*tag)->refcnt++;
1772 		return NULL;
1773 	}
1774 
1775 	return open_tag(tag, repo, id, 0);
1776 }
1777 
1778 const struct got_error *
1779 got_object_tag_open(struct got_tag_object **tag,
1780     struct got_repository *repo, struct got_object *obj)
1781 {
1782 	return open_tag(tag, repo, got_object_get_id(obj), 1);
1783 }
1784 
1785 const char *
1786 got_object_tag_get_name(struct got_tag_object *tag)
1787 {
1788 	return tag->tag;
1789 }
1790 
1791 int
1792 got_object_tag_get_object_type(struct got_tag_object *tag)
1793 {
1794 	return tag->obj_type;
1795 }
1796 
1797 struct got_object_id *
1798 got_object_tag_get_object_id(struct got_tag_object *tag)
1799 {
1800 	return &tag->id;
1801 }
1802 
1803 time_t
1804 got_object_tag_get_tagger_time(struct got_tag_object *tag)
1805 {
1806 	return tag->tagger_time;
1807 }
1808 
1809 time_t
1810 got_object_tag_get_tagger_gmtoff(struct got_tag_object *tag)
1811 {
1812 	return tag->tagger_gmtoff;
1813 }
1814 
1815 const char *
1816 got_object_tag_get_tagger(struct got_tag_object *tag)
1817 {
1818 	return tag->tagger;
1819 }
1820 
1821 const char *
1822 got_object_tag_get_message(struct got_tag_object *tag)
1823 {
1824 	return tag->tagmsg;
1825 }
1826 
1827 static struct got_tree_entry *
1828 find_entry_by_name(struct got_tree_object *tree, const char *name, size_t len)
1829 {
1830 	int i;
1831 
1832 	/* Note that tree entries are sorted in strncmp() order. */
1833 	for (i = 0; i < tree->nentries; i++) {
1834 		struct got_tree_entry *te = &tree->entries[i];
1835 		int cmp = strncmp(te->name, name, len);
1836 		if (cmp < 0)
1837 			continue;
1838 		if (cmp > 0)
1839 			break;
1840 		if (te->name[len] == '\0')
1841 			return te;
1842 	}
1843 	return NULL;
1844 }
1845 
1846 struct got_tree_entry *
1847 got_object_tree_find_entry(struct got_tree_object *tree, const char *name)
1848 {
1849 	return find_entry_by_name(tree, name, strlen(name));
1850 }
1851 
1852 const struct got_error *
1853 got_object_tree_find_path(struct got_object_id **id, mode_t *mode,
1854     struct got_repository *repo, struct got_tree_object *tree,
1855     const char *path)
1856 {
1857 	const struct got_error *err = NULL;
1858 	struct got_tree_object *subtree = NULL;
1859 	struct got_tree_entry *te = NULL;
1860 	const char *seg, *s;
1861 	size_t seglen;
1862 
1863 	*id = NULL;
1864 
1865 	s = path;
1866 	while (s[0] == '/')
1867 		s++;
1868 	seg = s;
1869 	seglen = 0;
1870 	subtree = tree;
1871 	while (*s) {
1872 		struct got_tree_object *next_tree;
1873 
1874 		if (*s != '/') {
1875 			s++;
1876 			seglen++;
1877 			if (*s)
1878 				continue;
1879 		}
1880 
1881 		te = find_entry_by_name(subtree, seg, seglen);
1882 		if (te == NULL) {
1883 			err = got_error_path(path, GOT_ERR_NO_TREE_ENTRY);
1884 			goto done;
1885 		}
1886 
1887 		if (*s == '\0')
1888 			break;
1889 
1890 		seg = s + 1;
1891 		seglen = 0;
1892 		s++;
1893 		if (*s) {
1894 			err = got_object_open_as_tree(&next_tree, repo,
1895 			    &te->id);
1896 			te = NULL;
1897 			if (err)
1898 				goto done;
1899 			if (subtree != tree)
1900 				got_object_tree_close(subtree);
1901 			subtree = next_tree;
1902 		}
1903 	}
1904 
1905 	if (te) {
1906 		*id = got_object_id_dup(&te->id);
1907 		if (*id == NULL)
1908 			return got_error_from_errno("got_object_id_dup");
1909 		if (mode)
1910 			*mode = te->mode;
1911 	} else
1912 		err = got_error_path(path, GOT_ERR_NO_TREE_ENTRY);
1913 done:
1914 	if (subtree && subtree != tree)
1915 		got_object_tree_close(subtree);
1916 	return err;
1917 }
1918 const struct got_error *
1919 got_object_id_by_path(struct got_object_id **id, struct got_repository *repo,
1920     struct got_object_id *commit_id, const char *path)
1921 {
1922 	const struct got_error *err = NULL;
1923 	struct got_commit_object *commit = NULL;
1924 	struct got_tree_object *tree = NULL;
1925 
1926 	*id = NULL;
1927 
1928 	err = got_object_open_as_commit(&commit, repo, commit_id);
1929 	if (err)
1930 		goto done;
1931 
1932 	/* Handle opening of root of commit's tree. */
1933 	if (got_path_is_root_dir(path)) {
1934 		*id = got_object_id_dup(commit->tree_id);
1935 		if (*id == NULL)
1936 			err = got_error_from_errno("got_object_id_dup");
1937 	} else {
1938 		err = got_object_open_as_tree(&tree, repo, commit->tree_id);
1939 		if (err)
1940 			goto done;
1941 		err = got_object_tree_find_path(id, NULL, repo, tree, path);
1942 	}
1943 done:
1944 	if (commit)
1945 		got_object_commit_close(commit);
1946 	if (tree)
1947 		got_object_tree_close(tree);
1948 	return err;
1949 }
1950 
1951 /*
1952  * Normalize file mode bits to avoid false positive tree entry differences
1953  * in case tree entries have unexpected mode bits set.
1954  */
1955 static mode_t
1956 normalize_mode_for_comparison(mode_t mode)
1957 {
1958 	/*
1959 	 * For directories, the only relevant bit is the IFDIR bit.
1960 	 * This allows us to detect paths changing from a directory
1961 	 * to a file and vice versa.
1962 	 */
1963 	if (S_ISDIR(mode))
1964 		return mode & S_IFDIR;
1965 
1966 	/*
1967 	 * For symlinks, the only relevant bit is the IFLNK bit.
1968 	 * This allows us to detect paths changing from a symlinks
1969 	 * to a file or directory and vice versa.
1970 	 */
1971 	if (S_ISLNK(mode))
1972 		return mode & S_IFLNK;
1973 
1974 	/* For files, the only change we care about is the executable bit. */
1975 	return mode & S_IXUSR;
1976 }
1977 
1978 const struct got_error *
1979 got_object_tree_path_changed(int *changed,
1980     struct got_tree_object *tree01, struct got_tree_object *tree02,
1981     const char *path, struct got_repository *repo)
1982 {
1983 	const struct got_error *err = NULL;
1984 	struct got_tree_object *tree1 = NULL, *tree2 = NULL;
1985 	struct got_tree_entry *te1 = NULL, *te2 = NULL;
1986 	const char *seg, *s;
1987 	size_t seglen;
1988 
1989 	*changed = 0;
1990 
1991 	/* We not do support comparing the root path. */
1992 	if (got_path_is_root_dir(path))
1993 		return got_error_path(path, GOT_ERR_BAD_PATH);
1994 
1995 	tree1 = tree01;
1996 	tree2 = tree02;
1997 	s = path;
1998 	while (*s == '/')
1999 		s++;
2000 	seg = s;
2001 	seglen = 0;
2002 	while (*s) {
2003 		struct got_tree_object *next_tree1, *next_tree2;
2004 		mode_t mode1, mode2;
2005 
2006 		if (*s != '/') {
2007 			s++;
2008 			seglen++;
2009 			if (*s)
2010 				continue;
2011 		}
2012 
2013 		te1 = find_entry_by_name(tree1, seg, seglen);
2014 		if (te1 == NULL) {
2015 			err = got_error(GOT_ERR_NO_OBJ);
2016 			goto done;
2017 		}
2018 
2019 		if (tree2)
2020 			te2 = find_entry_by_name(tree2, seg, seglen);
2021 
2022 		if (te2) {
2023 			mode1 = normalize_mode_for_comparison(te1->mode);
2024 			mode2 = normalize_mode_for_comparison(te2->mode);
2025 			if (mode1 != mode2) {
2026 				*changed = 1;
2027 				goto done;
2028 			}
2029 
2030 			if (got_object_id_cmp(&te1->id, &te2->id) == 0) {
2031 				*changed = 0;
2032 				goto done;
2033 			}
2034 		}
2035 
2036 		if (*s == '\0') { /* final path element */
2037 			*changed = 1;
2038 			goto done;
2039 		}
2040 
2041 		seg = s + 1;
2042 		s++;
2043 		seglen = 0;
2044 		if (*s) {
2045 			err = got_object_open_as_tree(&next_tree1, repo,
2046 			    &te1->id);
2047 			te1 = NULL;
2048 			if (err)
2049 				goto done;
2050 			if (tree1 != tree01)
2051 				got_object_tree_close(tree1);
2052 			tree1 = next_tree1;
2053 
2054 			if (te2) {
2055 				err = got_object_open_as_tree(&next_tree2, repo,
2056 				    &te2->id);
2057 				te2 = NULL;
2058 				if (err)
2059 					goto done;
2060 				if (tree2 != tree02)
2061 					got_object_tree_close(tree2);
2062 				tree2 = next_tree2;
2063 			} else if (tree2) {
2064 				if (tree2 != tree02)
2065 					got_object_tree_close(tree2);
2066 				tree2 = NULL;
2067 			}
2068 		}
2069 	}
2070 done:
2071 	if (tree1 && tree1 != tree01)
2072 		got_object_tree_close(tree1);
2073 	if (tree2 && tree2 != tree02)
2074 		got_object_tree_close(tree2);
2075 	return err;
2076 }
2077 
2078 const struct got_error *
2079 got_object_tree_entry_dup(struct got_tree_entry **new_te,
2080     struct got_tree_entry *te)
2081 {
2082 	const struct got_error *err = NULL;
2083 
2084 	*new_te = calloc(1, sizeof(**new_te));
2085 	if (*new_te == NULL)
2086 		return got_error_from_errno("calloc");
2087 
2088 	(*new_te)->mode = te->mode;
2089 	memcpy((*new_te)->name, te->name, sizeof((*new_te)->name));
2090 	memcpy(&(*new_te)->id, &te->id, sizeof((*new_te)->id));
2091 	return err;
2092 }
2093 
2094 int
2095 got_object_tree_entry_is_submodule(struct got_tree_entry *te)
2096 {
2097 	return (te->mode & S_IFMT) == (S_IFDIR | S_IFLNK);
2098 }
2099 
2100 int
2101 got_object_tree_entry_is_symlink(struct got_tree_entry *te)
2102 {
2103 	/* S_IFDIR check avoids confusing symlinks with submodules. */
2104 	return ((te->mode & (S_IFDIR | S_IFLNK)) == S_IFLNK);
2105 }
2106 
2107 static const struct got_error *
2108 resolve_symlink(char **link_target, const char *path,
2109     struct got_object_id *commit_id, struct got_repository *repo)
2110 {
2111 	const struct got_error *err = NULL;
2112 	char buf[PATH_MAX];
2113 	char *name, *parent_path = NULL;
2114 	struct got_object_id *tree_obj_id = NULL;
2115 	struct got_tree_object *tree = NULL;
2116 	struct got_tree_entry *te = NULL;
2117 
2118 	*link_target = NULL;
2119 
2120 	if (strlcpy(buf, path, sizeof(buf)) >= sizeof(buf))
2121 		return got_error(GOT_ERR_NO_SPACE);
2122 
2123 	name = basename(buf);
2124 	if (name == NULL)
2125 		return got_error_from_errno2("basename", path);
2126 
2127 	err = got_path_dirname(&parent_path, path);
2128 	if (err)
2129 		return err;
2130 
2131 	err = got_object_id_by_path(&tree_obj_id, repo, commit_id,
2132 	    parent_path);
2133 	if (err) {
2134 		if (err->code == GOT_ERR_NO_TREE_ENTRY) {
2135 			/* Display the complete path in error message. */
2136 			err = got_error_path(path, err->code);
2137 		}
2138 		goto done;
2139 	}
2140 
2141 	err = got_object_open_as_tree(&tree, repo, tree_obj_id);
2142 	if (err)
2143 		goto done;
2144 
2145 	te = got_object_tree_find_entry(tree, name);
2146 	if (te == NULL) {
2147 		err = got_error_path(path, GOT_ERR_NO_TREE_ENTRY);
2148 		goto done;
2149 	}
2150 
2151 	if (got_object_tree_entry_is_symlink(te)) {
2152 		err = got_tree_entry_get_symlink_target(link_target, te, repo);
2153 		if (err)
2154 			goto done;
2155 		if (!got_path_is_absolute(*link_target)) {
2156 			char *abspath;
2157 			if (asprintf(&abspath, "%s/%s", parent_path,
2158 			    *link_target) == -1) {
2159 				err = got_error_from_errno("asprintf");
2160 				goto done;
2161 			}
2162 			free(*link_target);
2163 			*link_target = malloc(PATH_MAX);
2164 			if (*link_target == NULL) {
2165 				err = got_error_from_errno("malloc");
2166 				goto done;
2167 			}
2168 			err = got_canonpath(abspath, *link_target, PATH_MAX);
2169 			free(abspath);
2170 			if (err)
2171 				goto done;
2172 		}
2173 	}
2174 done:
2175 	free(tree_obj_id);
2176 	if (tree)
2177 		got_object_tree_close(tree);
2178 	if (err) {
2179 		free(*link_target);
2180 		*link_target = NULL;
2181 	}
2182 	return err;
2183 }
2184 
2185 const struct got_error *
2186 got_object_resolve_symlinks(char **link_target, const char *path,
2187     struct got_object_id *commit_id, struct got_repository *repo)
2188 {
2189 	const struct got_error *err = NULL;
2190 	char *next_target = NULL;
2191 	int max_recursion = 40; /* matches Git */
2192 
2193 	*link_target = NULL;
2194 
2195 	do {
2196 		err = resolve_symlink(&next_target,
2197 		    *link_target ? *link_target : path, commit_id, repo);
2198 		if (err)
2199 			break;
2200 		if (next_target) {
2201 			free(*link_target);
2202 			if (--max_recursion == 0) {
2203 				err = got_error_path(path, GOT_ERR_RECURSION);
2204 				*link_target = NULL;
2205 				break;
2206 			}
2207 			*link_target = next_target;
2208 		}
2209 	} while (next_target);
2210 
2211 	return err;
2212 }
2213 
2214 const struct got_error *
2215 got_traverse_packed_commits(struct got_object_id_queue *traversed_commits,
2216     struct got_object_id *commit_id, const char *path,
2217     struct got_repository *repo)
2218 {
2219 	const struct got_error *err = NULL;
2220 	struct got_pack *pack = NULL;
2221 	struct got_packidx *packidx = NULL;
2222 	char *path_packfile = NULL;
2223 	struct got_commit_object *changed_commit = NULL;
2224 	struct got_object_id *changed_commit_id = NULL;
2225 	int idx;
2226 
2227 	err = got_repo_search_packidx(&packidx, &idx, repo, commit_id);
2228 	if (err) {
2229 		if (err->code != GOT_ERR_NO_OBJ)
2230 			return err;
2231 		return NULL;
2232 	}
2233 
2234 	err = got_packidx_get_packfile_path(&path_packfile,
2235 	    packidx->path_packidx);
2236 	if (err)
2237 		return err;
2238 
2239 	pack = got_repo_get_cached_pack(repo, path_packfile);
2240 	if (pack == NULL) {
2241 		err = got_repo_cache_pack(&pack, repo, path_packfile, packidx);
2242 		if (err)
2243 			goto done;
2244 	}
2245 
2246 	if (pack->privsep_child == NULL) {
2247 		err = start_pack_privsep_child(pack, packidx);
2248 		if (err)
2249 			goto done;
2250 	}
2251 
2252 	err = got_privsep_send_commit_traversal_request(
2253 	    pack->privsep_child->ibuf, commit_id, idx, path);
2254 	if (err)
2255 		goto done;
2256 
2257 	err = got_privsep_recv_traversed_commits(&changed_commit,
2258 	    &changed_commit_id, traversed_commits, pack->privsep_child->ibuf);
2259 	if (err)
2260 		goto done;
2261 
2262 	if (changed_commit) {
2263 		/*
2264 		 * Cache the commit in which the path was changed.
2265 		 * This commit might be opened again soon.
2266 		 */
2267 		changed_commit->refcnt++;
2268 		err = got_repo_cache_commit(repo, changed_commit_id,
2269 		    changed_commit);
2270 		got_object_commit_close(changed_commit);
2271 	}
2272 done:
2273 	free(path_packfile);
2274 	free(changed_commit_id);
2275 	return err;
2276 }