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Date:: Tue Jan 4 16:11:52 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/queue.h>
20 #include <sys/tree.h>
21 #include <sys/uio.h>
22 #include <sys/socket.h>
23 #include <sys/wait.h>
24 #include <sys/resource.h>
25 
26 #include <errno.h>
27 #include <fcntl.h>
28 #include <stdio.h>
29 #include <stdlib.h>
30 #include <string.h>
31 #include <stdint.h>
32 #include <sha1.h>
33 #include <unistd.h>
34 #include <zlib.h>
35 #include <ctype.h>
36 #include <libgen.h>
37 #include <limits.h>
38 #include <imsg.h>
39 #include <time.h>
40 
41 #include "got_error.h"
42 #include "got_object.h"
43 #include "got_repository.h"
44 #include "got_opentemp.h"
45 #include "got_path.h"
46 
47 #include "got_lib_sha1.h"
48 #include "got_lib_delta.h"
49 #include "got_lib_inflate.h"
50 #include "got_lib_object.h"
51 #include "got_lib_privsep.h"
52 #include "got_lib_object_idcache.h"
53 #include "got_lib_object_cache.h"
54 #include "got_lib_object_parse.h"
55 #include "got_lib_pack.h"
56 #include "got_lib_repository.h"
57 
58 #ifndef MIN
59 #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
60 #endif
61 
62 struct got_object_id *
63 got_object_get_id(struct got_object *obj)
64 {
65 	return &obj->id;
66 }
67 
68 const struct got_error *
69 got_object_get_id_str(char **outbuf, struct got_object *obj)
70 {
71 	return got_object_id_str(outbuf, &obj->id);
72 }
73 
74 const struct got_error *
75 got_object_get_type(int *type, struct got_repository *repo,
76     struct got_object_id *id)
77 {
78 	const struct got_error *err = NULL;
79 	struct got_object *obj;
80 
81 	err = got_object_open(&obj, repo, id);
82 	if (err)
83 		return err;
84 
85 	switch (obj->type) {
86 	case GOT_OBJ_TYPE_COMMIT:
87 	case GOT_OBJ_TYPE_TREE:
88 	case GOT_OBJ_TYPE_BLOB:
89 	case GOT_OBJ_TYPE_TAG:
90 		*type = obj->type;
91 		break;
92 	default:
93 		err = got_error(GOT_ERR_OBJ_TYPE);
94 		break;
95 	}
96 
97 	got_object_close(obj);
98 	return err;
99 }
100 
101 const struct got_error *
102 got_object_get_path(char **path, struct got_object_id *id,
103     struct got_repository *repo)
104 {
105 	const struct got_error *err = NULL;
106 	char *hex = NULL;
107 	char *path_objects;
108 
109 	*path = NULL;
110 
111 	path_objects = got_repo_get_path_objects(repo);
112 	if (path_objects == NULL)
113 		return got_error_from_errno("got_repo_get_path_objects");
114 
115 	err = got_object_id_str(&hex, id);
116 	if (err)
117 		goto done;
118 
119 	if (asprintf(path, "%s/%.2x/%s", path_objects,
120 	    id->sha1[0], hex + 2) == -1)
121 		err = got_error_from_errno("asprintf");
122 
123 done:
124 	free(hex);
125 	free(path_objects);
126 	return err;
127 }
128 
129 const struct got_error *
130 got_object_open_loose_fd(int *fd, struct got_object_id *id,
131     struct got_repository *repo)
132 {
133 	const struct got_error *err = NULL;
134 	char *path;
135 
136 	err = got_object_get_path(&path, id, repo);
137 	if (err)
138 		return err;
139 	*fd = open(path, O_RDONLY | O_NOFOLLOW | O_CLOEXEC);
140 	if (*fd == -1) {
141 		err = got_error_from_errno2("open", path);
142 		goto done;
143 	}
144 done:
145 	free(path);
146 	return err;
147 }
148 
149 static const struct got_error *
150 request_packed_object(struct got_object **obj, struct got_pack *pack, int idx,
151     struct got_object_id *id)
152 {
153 	const struct got_error *err = NULL;
154 	struct imsgbuf *ibuf = pack->privsep_child->ibuf;
155 
156 	err = got_privsep_send_packed_obj_req(ibuf, idx, id);
157 	if (err)
158 		return err;
159 
160 	err = got_privsep_recv_obj(obj, ibuf);
161 	if (err)
162 		return err;
163 
164 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
165 
166 	return NULL;
167 }
168 
169 /* Create temporary files used during delta application. */
170 static const struct got_error *
171 pack_child_send_tempfiles(struct imsgbuf *ibuf, struct got_pack *pack)
172 {
173 	const struct got_error *err;
174 	int basefd, accumfd;
175 
176 	/* 
177 	 * For performance reasons, the child will keep reusing the
178 	 * same temporary files during every object request.
179 	 * Opening and closing new files for every object request is
180 	 * too expensive during operations such as 'gotadmin pack'.
181 	 */
182 	if (pack->child_has_tempfiles)
183 		return NULL;
184 
185 	basefd = got_opentempfd();
186 	if (basefd == -1)
187 		return got_error_from_errno("got_opentempfd");
188 
189 	err = got_privsep_send_tmpfd(ibuf, basefd);
190 	if (err)
191 		return err;
192 
193 	accumfd = got_opentempfd();
194 	if (accumfd == -1)
195 		return got_error_from_errno("got_opentempfd");
196 
197 	err = got_privsep_send_tmpfd(ibuf, accumfd);
198 	if (err)
199 		return err;
200 
201 	pack->child_has_tempfiles = 1;
202 	return NULL;
203 }
204 
205 static const struct got_error *
206 request_packed_object_raw(uint8_t **outbuf, off_t *size, size_t *hdrlen,
207     int outfd, struct got_pack *pack, int idx, struct got_object_id *id)
208 {
209 	const struct got_error *err = NULL;
210 	struct imsgbuf *ibuf = pack->privsep_child->ibuf;
211 	int outfd_child;
212 
213 	 err = pack_child_send_tempfiles(ibuf, pack);
214 	 if (err)
215 		return err;
216 
217 	outfd_child = dup(outfd);
218 	if (outfd_child == -1)
219 		return got_error_from_errno("dup");
220 
221 	err = got_privsep_send_packed_raw_obj_req(ibuf, idx, id);
222 	if (err) {
223 		close(outfd_child);
224 		return err;
225 	}
226 
227 	err = got_privsep_send_raw_obj_outfd(ibuf, outfd_child);
228 	if (err)
229 		return err;
230 
231 	err = got_privsep_recv_raw_obj(outbuf, size, hdrlen, ibuf);
232 	if (err)
233 		return err;
234 
235 	return NULL;
236 }
237 
238 static void
239 set_max_datasize(void)
240 {
241 	struct rlimit rl;
242 
243 	if (getrlimit(RLIMIT_DATA, &rl) != 0)
244 		return;
245 
246 	rl.rlim_cur = rl.rlim_max;
247 	setrlimit(RLIMIT_DATA, &rl);
248 }
249 
250 static const struct got_error *
251 start_pack_privsep_child(struct got_pack *pack, struct got_packidx *packidx)
252 {
253 	const struct got_error *err = NULL;
254 	int imsg_fds[2];
255 	pid_t pid;
256 	struct imsgbuf *ibuf;
257 
258 	ibuf = calloc(1, sizeof(*ibuf));
259 	if (ibuf == NULL)
260 		return got_error_from_errno("calloc");
261 
262 	pack->privsep_child = calloc(1, sizeof(*pack->privsep_child));
263 	if (pack->privsep_child == NULL) {
264 		err = got_error_from_errno("calloc");
265 		free(ibuf);
266 		return err;
267 	}
268 	pack->child_has_tempfiles = 0;
269 
270 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1) {
271 		err = got_error_from_errno("socketpair");
272 		goto done;
273 	}
274 
275 	pid = fork();
276 	if (pid == -1) {
277 		err = got_error_from_errno("fork");
278 		goto done;
279 	} else if (pid == 0) {
280 		set_max_datasize();
281 		got_privsep_exec_child(imsg_fds, GOT_PATH_PROG_READ_PACK,
282 		    pack->path_packfile);
283 		/* not reached */
284 	}
285 
286 	if (close(imsg_fds[1]) == -1)
287 		return got_error_from_errno("close");
288 	pack->privsep_child->imsg_fd = imsg_fds[0];
289 	pack->privsep_child->pid = pid;
290 	imsg_init(ibuf, imsg_fds[0]);
291 	pack->privsep_child->ibuf = ibuf;
292 
293 	err = got_privsep_init_pack_child(ibuf, pack, packidx);
294 	if (err) {
295 		const struct got_error *child_err;
296 		err = got_privsep_send_stop(pack->privsep_child->imsg_fd);
297 		child_err = got_privsep_wait_for_child(
298 		    pack->privsep_child->pid);
299 		if (child_err && err == NULL)
300 			err = child_err;
301 	}
302 done:
303 	if (err) {
304 		free(ibuf);
305 		free(pack->privsep_child);
306 		pack->privsep_child = NULL;
307 	}
308 	return err;
309 }
310 
311 static const struct got_error *
312 read_packed_object_privsep(struct got_object **obj,
313     struct got_repository *repo, struct got_pack *pack,
314     struct got_packidx *packidx, int idx, struct got_object_id *id)
315 {
316 	const struct got_error *err = NULL;
317 
318 	if (pack->privsep_child == NULL) {
319 		err = start_pack_privsep_child(pack, packidx);
320 		if (err)
321 			return err;
322 	}
323 
324 	return request_packed_object(obj, pack, idx, id);
325 }
326 
327 static const struct got_error *
328 read_packed_object_raw_privsep(uint8_t **outbuf, off_t *size, size_t *hdrlen,
329     int outfd, struct got_pack *pack, struct got_packidx *packidx, int idx,
330     struct got_object_id *id)
331 {
332 	const struct got_error *err = NULL;
333 
334 	if (pack->privsep_child == NULL) {
335 		err = start_pack_privsep_child(pack, packidx);
336 		if (err)
337 			return err;
338 	}
339 
340 	return request_packed_object_raw(outbuf, size, hdrlen, outfd, pack,
341 	    idx, id);
342 }
343 
344 const struct got_error *
345 got_object_open_packed(struct got_object **obj, struct got_object_id *id,
346     struct got_repository *repo)
347 {
348 	const struct got_error *err = NULL;
349 	struct got_pack *pack = NULL;
350 	struct got_packidx *packidx = NULL;
351 	int idx;
352 	char *path_packfile;
353 
354 	err = got_repo_search_packidx(&packidx, &idx, repo, id);
355 	if (err)
356 		return err;
357 
358 	err = got_packidx_get_packfile_path(&path_packfile,
359 	    packidx->path_packidx);
360 	if (err)
361 		return err;
362 
363 	pack = got_repo_get_cached_pack(repo, path_packfile);
364 	if (pack == NULL) {
365 		err = got_repo_cache_pack(&pack, repo, path_packfile, packidx);
366 		if (err)
367 			goto done;
368 	}
369 
370 	err = read_packed_object_privsep(obj, repo, pack, packidx, idx, id);
371 	if (err)
372 		goto done;
373 done:
374 	free(path_packfile);
375 	return err;
376 }
377 
378 static const struct got_error *
379 request_object(struct got_object **obj, struct got_object_id *id,
380     struct got_repository *repo, int fd)
381 {
382 	const struct got_error *err = NULL;
383 	struct imsgbuf *ibuf;
384 
385 	ibuf = repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_OBJECT].ibuf;
386 
387 	err = got_privsep_send_obj_req(ibuf, fd, id);
388 	if (err)
389 		return err;
390 
391 	return got_privsep_recv_obj(obj, ibuf);
392 }
393 
394 static const struct got_error *
395 request_raw_object(uint8_t **outbuf, off_t *size, size_t *hdrlen, int outfd,
396     struct got_object_id *id, struct got_repository *repo, int infd)
397 {
398 	const struct got_error *err = NULL;
399 	struct imsgbuf *ibuf;
400 	int outfd_child;
401 
402 	ibuf = repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_OBJECT].ibuf;
403 
404 	outfd_child = dup(outfd);
405 	if (outfd_child == -1)
406 		return got_error_from_errno("dup");
407 
408 	err = got_privsep_send_raw_obj_req(ibuf, infd, id);
409 	if (err)
410 		return err;
411 
412 	err = got_privsep_send_raw_obj_outfd(ibuf, outfd_child);
413 	if (err)
414 		return err;
415 
416 	return got_privsep_recv_raw_obj(outbuf, size, hdrlen, ibuf);
417 }
418 
419 static const struct got_error *
420 start_read_object_child(struct got_repository *repo)
421 {
422 	const struct got_error *err = NULL;
423 	int imsg_fds[2];
424 	pid_t pid;
425 	struct imsgbuf *ibuf;
426 
427 	ibuf = calloc(1, sizeof(*ibuf));
428 	if (ibuf == NULL)
429 		return got_error_from_errno("calloc");
430 
431 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1) {
432 		err = got_error_from_errno("socketpair");
433 		free(ibuf);
434 		return err;
435 	}
436 
437 	pid = fork();
438 	if (pid == -1) {
439 		err = got_error_from_errno("fork");
440 		free(ibuf);
441 		return err;
442 	}
443 	else if (pid == 0) {
444 		got_privsep_exec_child(imsg_fds, GOT_PATH_PROG_READ_OBJECT,
445 		    repo->path);
446 		/* not reached */
447 	}
448 
449 	if (close(imsg_fds[1]) == -1) {
450 		err = got_error_from_errno("close");
451 		free(ibuf);
452 		return err;
453 	}
454 
455 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_OBJECT].imsg_fd =
456 	    imsg_fds[0];
457 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_OBJECT].pid = pid;
458 	imsg_init(ibuf, imsg_fds[0]);
459 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_OBJECT].ibuf = ibuf;
460 
461 	return NULL;
462 }
463 
464 const struct got_error *
465 got_object_read_header_privsep(struct got_object **obj,
466     struct got_object_id *id, struct got_repository *repo, int obj_fd)
467 {
468 	const struct got_error *err;
469 
470 	if (repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_OBJECT].imsg_fd != -1)
471 		return request_object(obj, id, repo, obj_fd);
472 
473 	err = start_read_object_child(repo);
474 	if (err) {
475 		close(obj_fd);
476 		return err;
477 	}
478 
479 	return request_object(obj, id, repo, obj_fd);
480 }
481 
482 static const struct got_error *
483 read_object_raw_privsep(uint8_t **outbuf, off_t *size, size_t *hdrlen,
484     int outfd, struct got_object_id *id, struct got_repository *repo,
485     int obj_fd)
486 {
487 	const struct got_error *err;
488 
489 	if (repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_OBJECT].imsg_fd != -1)
490 		return request_raw_object(outbuf, size, hdrlen, outfd, id,
491 		    repo, obj_fd);
492 
493 	err = start_read_object_child(repo);
494 	if (err)
495 		return err;
496 
497 	return request_raw_object(outbuf, size, hdrlen, outfd, id, repo,
498 	    obj_fd);
499 }
500 
501 const struct got_error *
502 got_object_open(struct got_object **obj, struct got_repository *repo,
503     struct got_object_id *id)
504 {
505 	const struct got_error *err = NULL;
506 	int fd;
507 
508 	*obj = got_repo_get_cached_object(repo, id);
509 	if (*obj != NULL) {
510 		(*obj)->refcnt++;
511 		return NULL;
512 	}
513 
514 	err = got_object_open_packed(obj, id, repo);
515 	if (err && err->code != GOT_ERR_NO_OBJ)
516 		return err;
517 	if (*obj) {
518 		(*obj)->refcnt++;
519 		return got_repo_cache_object(repo, id, *obj);
520 	}
521 
522 	err = got_object_open_loose_fd(&fd, id, repo);
523 	if (err) {
524 		if (err->code == GOT_ERR_ERRNO && errno == ENOENT)
525 			err = got_error_no_obj(id);
526 		return err;
527 	}
528 
529 	err = got_object_read_header_privsep(obj, id, repo, fd);
530 	if (err)
531 		return err;
532 
533 	memcpy((*obj)->id.sha1, id->sha1, SHA1_DIGEST_LENGTH);
534 
535 	(*obj)->refcnt++;
536 	return got_repo_cache_object(repo, id, *obj);
537 }
538 
539 /* *outfd must be initialized to -1 by caller */
540 const struct got_error *
541 got_object_raw_open(struct got_raw_object **obj, int *outfd,
542     struct got_repository *repo, struct got_object_id *id)
543 {
544 	const struct got_error *err = NULL;
545 	struct got_packidx *packidx = NULL;
546 	int idx;
547 	uint8_t *outbuf = NULL;
548 	off_t size = 0;
549 	size_t hdrlen = 0;
550 	char *path_packfile = NULL;
551 
552 	*obj = got_repo_get_cached_raw_object(repo, id);
553 	if (*obj != NULL) {
554 		(*obj)->refcnt++;
555 		return NULL;
556 	}
557 
558 	if (*outfd == -1) {
559 		*outfd = got_opentempfd();
560 		if (*outfd == -1)
561 			return got_error_from_errno("got_opentempfd");
562 	}
563 
564 	err = got_repo_search_packidx(&packidx, &idx, repo, id);
565 	if (err == NULL) {
566 		struct got_pack *pack = NULL;
567 
568 		err = got_packidx_get_packfile_path(&path_packfile,
569 		    packidx->path_packidx);
570 		if (err)
571 			goto done;
572 
573 		pack = got_repo_get_cached_pack(repo, path_packfile);
574 		if (pack == NULL) {
575 			err = got_repo_cache_pack(&pack, repo, path_packfile,
576 			    packidx);
577 			if (err)
578 				goto done;
579 		}
580 		err = read_packed_object_raw_privsep(&outbuf, &size, &hdrlen,
581 		    *outfd, pack, packidx, idx, id);
582 		if (err)
583 			goto done;
584 	} else if (err->code == GOT_ERR_NO_OBJ) {
585 		int fd;
586 
587 		err = got_object_open_loose_fd(&fd, id, repo);
588 		if (err)
589 			goto done;
590 		err = read_object_raw_privsep(&outbuf, &size, &hdrlen, *outfd,
591 		    id, repo, fd);
592 		if (err)
593 			goto done;
594 	}
595 
596 	*obj = calloc(1, sizeof(**obj));
597 	if (*obj == NULL) {
598 		err = got_error_from_errno("calloc");
599 		goto done;
600 	}
601 
602 	if (outbuf) {
603 		(*obj)->f = fmemopen(outbuf, hdrlen + size, "r");
604 		if ((*obj)->f == NULL) {
605 			err = got_error_from_errno("fdopen");
606 			goto done;
607 		}
608 		(*obj)->data = outbuf;
609 	} else {
610 		struct stat sb;
611 		if (fstat(*outfd, &sb) == -1) {
612 			err = got_error_from_errno("fstat");
613 			goto done;
614 		}
615 
616 		if (sb.st_size != hdrlen + size) {
617 			err = got_error(GOT_ERR_PRIVSEP_LEN);
618 			goto done;
619 		}
620 
621 		(*obj)->f = fdopen(*outfd, "r");
622 		if ((*obj)->f == NULL) {
623 			err = got_error_from_errno("fdopen");
624 			goto done;
625 		}
626 		(*obj)->data = NULL;
627 		*outfd = -1;
628 	}
629 	(*obj)->hdrlen = hdrlen;
630 	(*obj)->size = size;
631 	err = got_repo_cache_raw_object(repo, id, *obj);
632 done:
633 	free(path_packfile);
634 	if (err) {
635 		if (*obj) {
636 			got_object_raw_close(*obj);
637 			*obj = NULL;
638 		}
639 		free(outbuf);
640 	} else
641 		(*obj)->refcnt++;
642 	return err;
643 }
644 
645 const struct got_error *
646 got_object_open_by_id_str(struct got_object **obj, struct got_repository *repo,
647     const char *id_str)
648 {
649 	struct got_object_id id;
650 
651 	if (!got_parse_sha1_digest(id.sha1, id_str))
652 		return got_error_path(id_str, GOT_ERR_BAD_OBJ_ID_STR);
653 
654 	return got_object_open(obj, repo, &id);
655 }
656 
657 const struct got_error *
658 got_object_resolve_id_str(struct got_object_id **id,
659     struct got_repository *repo, const char *id_str)
660 {
661 	const struct got_error *err = NULL;
662 	struct got_object *obj;
663 
664 	err = got_object_open_by_id_str(&obj, repo, id_str);
665 	if (err)
666 		return err;
667 
668 	*id = got_object_id_dup(got_object_get_id(obj));
669 	got_object_close(obj);
670 	if (*id == NULL)
671 		return got_error_from_errno("got_object_id_dup");
672 
673 	return NULL;
674 }
675 
676 static const struct got_error *
677 request_packed_commit(struct got_commit_object **commit, struct got_pack *pack,
678     int pack_idx, struct got_object_id *id)
679 {
680 	const struct got_error *err = NULL;
681 
682 	err = got_privsep_send_commit_req(pack->privsep_child->ibuf, -1, id,
683 	    pack_idx);
684 	if (err)
685 		return err;
686 
687 	err = got_privsep_recv_commit(commit, pack->privsep_child->ibuf);
688 	if (err)
689 		return err;
690 
691 	(*commit)->flags |= GOT_COMMIT_FLAG_PACKED;
692 	return NULL;
693 }
694 
695 static const struct got_error *
696 read_packed_commit_privsep(struct got_commit_object **commit,
697     struct got_pack *pack, struct got_packidx *packidx, int idx,
698     struct got_object_id *id)
699 {
700 	const struct got_error *err = NULL;
701 
702 	if (pack->privsep_child)
703 		return request_packed_commit(commit, pack, idx, id);
704 
705 	err = start_pack_privsep_child(pack, packidx);
706 	if (err)
707 		return err;
708 
709 	return request_packed_commit(commit, pack, idx, id);
710 }
711 
712 static const struct got_error *
713 request_commit(struct got_commit_object **commit, struct got_repository *repo,
714     int fd, struct got_object_id *id)
715 {
716 	const struct got_error *err = NULL;
717 	struct imsgbuf *ibuf;
718 
719 	ibuf = repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_COMMIT].ibuf;
720 
721 	err = got_privsep_send_commit_req(ibuf, fd, id, -1);
722 	if (err)
723 		return err;
724 
725 	return got_privsep_recv_commit(commit, ibuf);
726 }
727 
728 static const struct got_error *
729 read_commit_privsep(struct got_commit_object **commit, int obj_fd,
730     struct got_object_id *id, struct got_repository *repo)
731 {
732 	const struct got_error *err;
733 	int imsg_fds[2];
734 	pid_t pid;
735 	struct imsgbuf *ibuf;
736 
737 	if (repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_COMMIT].imsg_fd != -1)
738 		return request_commit(commit, repo, obj_fd, id);
739 
740 	ibuf = calloc(1, sizeof(*ibuf));
741 	if (ibuf == NULL)
742 		return got_error_from_errno("calloc");
743 
744 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1) {
745 		err = got_error_from_errno("socketpair");
746 		free(ibuf);
747 		return err;
748 	}
749 
750 	pid = fork();
751 	if (pid == -1) {
752 		err = got_error_from_errno("fork");
753 		free(ibuf);
754 		return err;
755 	}
756 	else if (pid == 0) {
757 		got_privsep_exec_child(imsg_fds, GOT_PATH_PROG_READ_COMMIT,
758 		    repo->path);
759 		/* not reached */
760 	}
761 
762 	if (close(imsg_fds[1]) == -1) {
763 		err = got_error_from_errno("close");
764 		free(ibuf);
765 		return err;
766 	}
767 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_COMMIT].imsg_fd =
768 	    imsg_fds[0];
769 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_COMMIT].pid = pid;
770 	imsg_init(ibuf, imsg_fds[0]);
771 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_COMMIT].ibuf = ibuf;
772 
773 	return request_commit(commit, repo, obj_fd, id);
774 }
775 
776 
777 static const struct got_error *
778 open_commit(struct got_commit_object **commit,
779     struct got_repository *repo, struct got_object_id *id, int check_cache)
780 {
781 	const struct got_error *err = NULL;
782 	struct got_packidx *packidx = NULL;
783 	int idx;
784 	char *path_packfile = NULL;
785 
786 	if (check_cache) {
787 		*commit = got_repo_get_cached_commit(repo, id);
788 		if (*commit != NULL) {
789 			(*commit)->refcnt++;
790 			return NULL;
791 		}
792 	} else
793 		*commit = NULL;
794 
795 	err = got_repo_search_packidx(&packidx, &idx, repo, id);
796 	if (err == NULL) {
797 		struct got_pack *pack = NULL;
798 
799 		err = got_packidx_get_packfile_path(&path_packfile,
800 		    packidx->path_packidx);
801 		if (err)
802 			return err;
803 
804 		pack = got_repo_get_cached_pack(repo, path_packfile);
805 		if (pack == NULL) {
806 			err = got_repo_cache_pack(&pack, repo, path_packfile,
807 			    packidx);
808 			if (err)
809 				goto done;
810 		}
811 		err = read_packed_commit_privsep(commit, pack,
812 		    packidx, idx, id);
813 	} else if (err->code == GOT_ERR_NO_OBJ) {
814 		int fd;
815 
816 		err = got_object_open_loose_fd(&fd, id, repo);
817 		if (err)
818 			return err;
819 		err = read_commit_privsep(commit, fd, id, repo);
820 	}
821 
822 	if (err == NULL) {
823 		(*commit)->refcnt++;
824 		err = got_repo_cache_commit(repo, id, *commit);
825 	}
826 done:
827 	free(path_packfile);
828 	return err;
829 }
830 
831 const struct got_error *
832 got_object_open_as_commit(struct got_commit_object **commit,
833     struct got_repository *repo, struct got_object_id *id)
834 {
835 	*commit = got_repo_get_cached_commit(repo, id);
836 	if (*commit != NULL) {
837 		(*commit)->refcnt++;
838 		return NULL;
839 	}
840 
841 	return open_commit(commit, repo, id, 0);
842 }
843 
844 const struct got_error *
845 got_object_commit_open(struct got_commit_object **commit,
846     struct got_repository *repo, struct got_object *obj)
847 {
848 	return open_commit(commit, repo, got_object_get_id(obj), 1);
849 }
850 
851 const struct got_error *
852 got_object_qid_alloc(struct got_object_qid **qid, struct got_object_id *id)
853 {
854 	const struct got_error *err = NULL;
855 
856 	*qid = calloc(1, sizeof(**qid));
857 	if (*qid == NULL)
858 		return got_error_from_errno("calloc");
859 
860 	(*qid)->id = got_object_id_dup(id);
861 	if ((*qid)->id == NULL) {
862 		err = got_error_from_errno("got_object_id_dup");
863 		got_object_qid_free(*qid);
864 		*qid = NULL;
865 		return err;
866 	}
867 
868 	return NULL;
869 }
870 
871 const struct got_error *
872 got_object_id_queue_copy(const struct got_object_id_queue *src,
873     struct got_object_id_queue *dest)
874 {
875 	const struct got_error *err;
876 	struct got_object_qid *qid;
877 
878 	STAILQ_FOREACH(qid, src, entry) {
879 		struct got_object_qid *new;
880 		/*
881 		 * Deep-copy the object ID only. Let the caller deal
882 		 * with setting up the new->data pointer if needed.
883 		 */
884 		err = got_object_qid_alloc(&new, qid->id); 
885 		if (err) {
886 			got_object_id_queue_free(dest);
887 			return err;
888 		}
889 		STAILQ_INSERT_TAIL(dest, new, entry);
890 	}
891 
892 	return NULL;
893 }
894 
895 static const struct got_error *
896 request_packed_tree(struct got_tree_object **tree, struct got_pack *pack,
897     int pack_idx, struct got_object_id *id)
898 {
899 	const struct got_error *err = NULL;
900 
901 	err = got_privsep_send_tree_req(pack->privsep_child->ibuf, -1, id,
902 	    pack_idx);
903 	if (err)
904 		return err;
905 
906 	return got_privsep_recv_tree(tree, pack->privsep_child->ibuf);
907 }
908 
909 static const struct got_error *
910 read_packed_tree_privsep(struct got_tree_object **tree,
911     struct got_pack *pack, struct got_packidx *packidx, int idx,
912     struct got_object_id *id)
913 {
914 	const struct got_error *err = NULL;
915 
916 	if (pack->privsep_child)
917 		return request_packed_tree(tree, pack, idx, id);
918 
919 	err = start_pack_privsep_child(pack, packidx);
920 	if (err)
921 		return err;
922 
923 	return request_packed_tree(tree, pack, idx, id);
924 }
925 
926 static const struct got_error *
927 request_tree(struct got_tree_object **tree, struct got_repository *repo,
928     int fd, struct got_object_id *id)
929 {
930 	const struct got_error *err = NULL;
931 	struct imsgbuf *ibuf;
932 
933 	ibuf = repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_TREE].ibuf;
934 
935 	err = got_privsep_send_tree_req(ibuf, fd, id, -1);
936 	if (err)
937 		return err;
938 
939 	return got_privsep_recv_tree(tree, ibuf);
940 }
941 
942 const struct got_error *
943 read_tree_privsep(struct got_tree_object **tree, int obj_fd,
944     struct got_object_id *id, struct got_repository *repo)
945 {
946 	const struct got_error *err;
947 	int imsg_fds[2];
948 	pid_t pid;
949 	struct imsgbuf *ibuf;
950 
951 	if (repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_TREE].imsg_fd != -1)
952 		return request_tree(tree, repo, obj_fd, id);
953 
954 	ibuf = calloc(1, sizeof(*ibuf));
955 	if (ibuf == NULL)
956 		return got_error_from_errno("calloc");
957 
958 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1) {
959 		err = got_error_from_errno("socketpair");
960 		free(ibuf);
961 		return err;
962 	}
963 
964 	pid = fork();
965 	if (pid == -1) {
966 		err = got_error_from_errno("fork");
967 		free(ibuf);
968 		return err;
969 	}
970 	else if (pid == 0) {
971 		got_privsep_exec_child(imsg_fds, GOT_PATH_PROG_READ_TREE,
972 		    repo->path);
973 		/* not reached */
974 	}
975 
976 	if (close(imsg_fds[1]) == -1) {
977 		err = got_error_from_errno("close");
978 		free(ibuf);
979 		return err;
980 	}
981 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_TREE].imsg_fd =
982 	    imsg_fds[0];
983 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_TREE].pid = pid;
984 	imsg_init(ibuf, imsg_fds[0]);
985 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_TREE].ibuf = ibuf;
986 
987 
988 	return request_tree(tree, repo, obj_fd, id);
989 }
990 
991 static const struct got_error *
992 open_tree(struct got_tree_object **tree, struct got_repository *repo,
993     struct got_object_id *id, int check_cache)
994 {
995 	const struct got_error *err = NULL;
996 	struct got_packidx *packidx = NULL;
997 	int idx;
998 	char *path_packfile = NULL;
999 
1000 	if (check_cache) {
1001 		*tree = got_repo_get_cached_tree(repo, id);
1002 		if (*tree != NULL) {
1003 			(*tree)->refcnt++;
1004 			return NULL;
1005 		}
1006 	} else
1007 		*tree = NULL;
1008 
1009 	err = got_repo_search_packidx(&packidx, &idx, repo, id);
1010 	if (err == NULL) {
1011 		struct got_pack *pack = NULL;
1012 
1013 		err = got_packidx_get_packfile_path(&path_packfile,
1014 		    packidx->path_packidx);
1015 		if (err)
1016 			return err;
1017 
1018 		pack = got_repo_get_cached_pack(repo, path_packfile);
1019 		if (pack == NULL) {
1020 			err = got_repo_cache_pack(&pack, repo, path_packfile,
1021 			    packidx);
1022 			if (err)
1023 				goto done;
1024 		}
1025 		err = read_packed_tree_privsep(tree, pack,
1026 		    packidx, idx, id);
1027 	} else if (err->code == GOT_ERR_NO_OBJ) {
1028 		int fd;
1029 
1030 		err = got_object_open_loose_fd(&fd, id, repo);
1031 		if (err)
1032 			return err;
1033 		err = read_tree_privsep(tree, fd, id, repo);
1034 	}
1035 
1036 	if (err == NULL) {
1037 		(*tree)->refcnt++;
1038 		err = got_repo_cache_tree(repo, id, *tree);
1039 	}
1040 done:
1041 	free(path_packfile);
1042 	return err;
1043 }
1044 
1045 const struct got_error *
1046 got_object_open_as_tree(struct got_tree_object **tree,
1047     struct got_repository *repo, struct got_object_id *id)
1048 {
1049 	*tree = got_repo_get_cached_tree(repo, id);
1050 	if (*tree != NULL) {
1051 		(*tree)->refcnt++;
1052 		return NULL;
1053 	}
1054 
1055 	return open_tree(tree, repo, id, 0);
1056 }
1057 
1058 const struct got_error *
1059 got_object_tree_open(struct got_tree_object **tree,
1060     struct got_repository *repo, struct got_object *obj)
1061 {
1062 	return open_tree(tree, repo, got_object_get_id(obj), 1);
1063 }
1064 
1065 int
1066 got_object_tree_get_nentries(struct got_tree_object *tree)
1067 {
1068 	return tree->nentries;
1069 }
1070 
1071 struct got_tree_entry *
1072 got_object_tree_get_first_entry(struct got_tree_object *tree)
1073 {
1074 	return got_object_tree_get_entry(tree, 0);
1075 }
1076 
1077 struct got_tree_entry *
1078 got_object_tree_get_last_entry(struct got_tree_object *tree)
1079 {
1080 	return got_object_tree_get_entry(tree, tree->nentries - 1);
1081 }
1082 
1083 struct got_tree_entry *
1084 got_object_tree_get_entry(struct got_tree_object *tree, int i)
1085 {
1086 	if (i < 0 || i >= tree->nentries)
1087 		return NULL;
1088 	return &tree->entries[i];
1089 }
1090 
1091 mode_t
1092 got_tree_entry_get_mode(struct got_tree_entry *te)
1093 {
1094 	return te->mode;
1095 }
1096 
1097 const char *
1098 got_tree_entry_get_name(struct got_tree_entry *te)
1099 {
1100 	return &te->name[0];
1101 }
1102 
1103 struct got_object_id *
1104 got_tree_entry_get_id(struct got_tree_entry *te)
1105 {
1106 	return &te->id;
1107 }
1108 
1109 const struct got_error *
1110 got_object_blob_read_to_str(char **s, struct got_blob_object *blob)
1111 {
1112 	const struct got_error *err = NULL;
1113 	size_t len, totlen, hdrlen, offset;
1114 
1115 	*s = NULL;
1116 
1117 	hdrlen = got_object_blob_get_hdrlen(blob);
1118 	totlen = 0;
1119 	offset = 0;
1120 	do {
1121 		char *p;
1122 
1123 		err = got_object_blob_read_block(&len, blob);
1124 		if (err)
1125 			return err;
1126 
1127 		if (len == 0)
1128 			break;
1129 
1130 		totlen += len - hdrlen;
1131 		p = realloc(*s, totlen + 1);
1132 		if (p == NULL) {
1133 			err = got_error_from_errno("realloc");
1134 			free(*s);
1135 			*s = NULL;
1136 			return err;
1137 		}
1138 		*s = p;
1139 		/* Skip blob object header first time around. */
1140 		memcpy(*s + offset,
1141 		    got_object_blob_get_read_buf(blob) + hdrlen, len - hdrlen);
1142 		hdrlen = 0;
1143 		offset = totlen;
1144 	} while (len > 0);
1145 
1146 	(*s)[totlen] = '\0';
1147 	return NULL;
1148 }
1149 
1150 const struct got_error *
1151 got_tree_entry_get_symlink_target(char **link_target, struct got_tree_entry *te,
1152     struct got_repository *repo)
1153 {
1154 	const struct got_error *err = NULL;
1155 	struct got_blob_object *blob = NULL;
1156 
1157 	*link_target = NULL;
1158 
1159 	if (!got_object_tree_entry_is_symlink(te))
1160 		return got_error(GOT_ERR_TREE_ENTRY_TYPE);
1161 
1162 	err = got_object_open_as_blob(&blob, repo,
1163 	    got_tree_entry_get_id(te), PATH_MAX);
1164 	if (err)
1165 		return err;
1166 
1167 	err = got_object_blob_read_to_str(link_target, blob);
1168 	got_object_blob_close(blob);
1169 	if (err) {
1170 		free(*link_target);
1171 		*link_target = NULL;
1172 	}
1173 	return err;
1174 }
1175 
1176 int
1177 got_tree_entry_get_index(struct got_tree_entry *te)
1178 {
1179 	return te->idx;
1180 }
1181 
1182 struct got_tree_entry *
1183 got_tree_entry_get_next(struct got_tree_object *tree,
1184     struct got_tree_entry *te)
1185 {
1186 	return got_object_tree_get_entry(tree, te->idx + 1);
1187 }
1188 
1189 struct got_tree_entry *
1190 got_tree_entry_get_prev(struct got_tree_object *tree,
1191     struct got_tree_entry *te)
1192 {
1193 	return got_object_tree_get_entry(tree, te->idx - 1);
1194 }
1195 
1196 static const struct got_error *
1197 request_packed_blob(uint8_t **outbuf, size_t *size, size_t *hdrlen, int outfd,
1198     struct got_pack *pack, struct got_packidx *packidx, int idx,
1199     struct got_object_id *id)
1200 {
1201 	const struct got_error *err = NULL;
1202 	struct imsgbuf *ibuf = pack->privsep_child->ibuf;
1203 	int outfd_child;
1204 
1205 	 err = pack_child_send_tempfiles(ibuf, pack);
1206 	 if (err)
1207 		return err;
1208 
1209 	outfd_child = dup(outfd);
1210 	if (outfd_child == -1)
1211 		return got_error_from_errno("dup");
1212 
1213 	err = got_privsep_send_blob_req(pack->privsep_child->ibuf, -1, id, idx);
1214 	if (err)
1215 		return err;
1216 
1217 	err = got_privsep_send_blob_outfd(pack->privsep_child->ibuf,
1218 	    outfd_child);
1219 	if (err) {
1220 		return err;
1221 	}
1222 
1223 	err = got_privsep_recv_blob(outbuf, size, hdrlen,
1224 	    pack->privsep_child->ibuf);
1225 	if (err)
1226 		return err;
1227 
1228 	if (lseek(outfd, SEEK_SET, 0) == -1)
1229 		err = got_error_from_errno("lseek");
1230 
1231 	return err;
1232 }
1233 
1234 static const struct got_error *
1235 read_packed_blob_privsep(uint8_t **outbuf, size_t *size, size_t *hdrlen,
1236     int outfd, struct got_pack *pack, struct got_packidx *packidx, int idx,
1237     struct got_object_id *id)
1238 {
1239 	const struct got_error *err = NULL;
1240 
1241 	if (pack->privsep_child == NULL) {
1242 		err = start_pack_privsep_child(pack, packidx);
1243 		if (err)
1244 			return err;
1245 	}
1246 
1247 	return request_packed_blob(outbuf, size, hdrlen, outfd, pack, packidx,
1248 	    idx, id);
1249 }
1250 
1251 static const struct got_error *
1252 request_blob(uint8_t **outbuf, size_t *size, size_t *hdrlen, int outfd,
1253     int infd, struct got_object_id *id, struct imsgbuf *ibuf)
1254 {
1255 	const struct got_error *err = NULL;
1256 	int outfd_child;
1257 
1258 	outfd_child = dup(outfd);
1259 	if (outfd_child == -1)
1260 		return got_error_from_errno("dup");
1261 
1262 	err = got_privsep_send_blob_req(ibuf, infd, id, -1);
1263 	if (err)
1264 		return err;
1265 
1266 	err = got_privsep_send_blob_outfd(ibuf, outfd_child);
1267 	if (err)
1268 		return err;
1269 
1270 	err = got_privsep_recv_blob(outbuf, size, hdrlen, ibuf);
1271 	if (err)
1272 		return err;
1273 
1274 	if (lseek(outfd, SEEK_SET, 0) == -1)
1275 		return got_error_from_errno("lseek");
1276 
1277 	return err;
1278 }
1279 
1280 static const struct got_error *
1281 read_blob_privsep(uint8_t **outbuf, size_t *size, size_t *hdrlen,
1282     int outfd, int infd, struct got_object_id *id, struct got_repository *repo)
1283 {
1284 	const struct got_error *err;
1285 	int imsg_fds[2];
1286 	pid_t pid;
1287 	struct imsgbuf *ibuf;
1288 
1289 	if (repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_BLOB].imsg_fd != -1) {
1290 		ibuf = repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_BLOB].ibuf;
1291 		return request_blob(outbuf, size, hdrlen, outfd, infd, id,
1292 		    ibuf);
1293 	}
1294 
1295 	ibuf = calloc(1, sizeof(*ibuf));
1296 	if (ibuf == NULL)
1297 		return got_error_from_errno("calloc");
1298 
1299 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1) {
1300 		err = got_error_from_errno("socketpair");
1301 		free(ibuf);
1302 		return err;
1303 	}
1304 
1305 	pid = fork();
1306 	if (pid == -1) {
1307 		err = got_error_from_errno("fork");
1308 		free(ibuf);
1309 		return err;
1310 	}
1311 	else if (pid == 0) {
1312 		got_privsep_exec_child(imsg_fds, GOT_PATH_PROG_READ_BLOB,
1313 		    repo->path);
1314 		/* not reached */
1315 	}
1316 
1317 	if (close(imsg_fds[1]) == -1) {
1318 		err = got_error_from_errno("close");
1319 		free(ibuf);
1320 		return err;
1321 	}
1322 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_BLOB].imsg_fd =
1323 	    imsg_fds[0];
1324 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_BLOB].pid = pid;
1325 	imsg_init(ibuf, imsg_fds[0]);
1326 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_BLOB].ibuf = ibuf;
1327 
1328 	return request_blob(outbuf, size, hdrlen, outfd, infd, id, ibuf);
1329 }
1330 
1331 static const struct got_error *
1332 open_blob(struct got_blob_object **blob, struct got_repository *repo,
1333     struct got_object_id *id, size_t blocksize)
1334 {
1335 	const struct got_error *err = NULL;
1336 	struct got_packidx *packidx = NULL;
1337 	int idx;
1338 	char *path_packfile = NULL;
1339 	uint8_t *outbuf;
1340 	int outfd;
1341 	size_t size, hdrlen;
1342 	struct stat sb;
1343 
1344 	*blob = calloc(1, sizeof(**blob));
1345 	if (*blob == NULL)
1346 		return got_error_from_errno("calloc");
1347 
1348 	outfd = got_opentempfd();
1349 	if (outfd == -1)
1350 		return got_error_from_errno("got_opentempfd");
1351 
1352 	(*blob)->read_buf = malloc(blocksize);
1353 	if ((*blob)->read_buf == NULL) {
1354 		err = got_error_from_errno("malloc");
1355 		goto done;
1356 	}
1357 
1358 	err = got_repo_search_packidx(&packidx, &idx, repo, id);
1359 	if (err == NULL) {
1360 		struct got_pack *pack = NULL;
1361 
1362 		err = got_packidx_get_packfile_path(&path_packfile,
1363 		    packidx->path_packidx);
1364 		if (err)
1365 			goto done;
1366 
1367 		pack = got_repo_get_cached_pack(repo, path_packfile);
1368 		if (pack == NULL) {
1369 			err = got_repo_cache_pack(&pack, repo, path_packfile,
1370 			    packidx);
1371 			if (err)
1372 				goto done;
1373 		}
1374 		err = read_packed_blob_privsep(&outbuf, &size, &hdrlen, outfd,
1375 		    pack, packidx, idx, id);
1376 	} else if (err->code == GOT_ERR_NO_OBJ) {
1377 		int infd;
1378 
1379 		err = got_object_open_loose_fd(&infd, id, repo);
1380 		if (err)
1381 			goto done;
1382 		err = read_blob_privsep(&outbuf, &size, &hdrlen, outfd, infd,
1383 		    id, repo);
1384 	}
1385 	if (err)
1386 		goto done;
1387 
1388 	if (hdrlen > size) {
1389 		err = got_error(GOT_ERR_BAD_OBJ_HDR);
1390 		goto done;
1391 	}
1392 
1393 	if (outbuf) {
1394 		if (close(outfd) == -1 && err == NULL)
1395 			err = got_error_from_errno("close");
1396 		outfd = -1;
1397 		(*blob)->f = fmemopen(outbuf, size, "rb");
1398 		if ((*blob)->f == NULL) {
1399 			err = got_error_from_errno("fmemopen");
1400 			free(outbuf);
1401 			goto done;
1402 		}
1403 		(*blob)->data = outbuf;
1404 	} else {
1405 		if (fstat(outfd, &sb) == -1) {
1406 			err = got_error_from_errno("fstat");
1407 			goto done;
1408 		}
1409 
1410 		if (sb.st_size != size) {
1411 			err = got_error(GOT_ERR_PRIVSEP_LEN);
1412 			goto done;
1413 		}
1414 
1415 		(*blob)->f = fdopen(outfd, "rb");
1416 		if ((*blob)->f == NULL) {
1417 			err = got_error_from_errno("fdopen");
1418 			close(outfd);
1419 			outfd = -1;
1420 			goto done;
1421 		}
1422 	}
1423 
1424 	(*blob)->hdrlen = hdrlen;
1425 	(*blob)->blocksize = blocksize;
1426 	memcpy(&(*blob)->id.sha1, id->sha1, SHA1_DIGEST_LENGTH);
1427 
1428 done:
1429 	free(path_packfile);
1430 	if (err) {
1431 		if (*blob) {
1432 			got_object_blob_close(*blob);
1433 			*blob = NULL;
1434 		} else if (outfd != -1)
1435 			close(outfd);
1436 	}
1437 	return err;
1438 }
1439 
1440 const struct got_error *
1441 got_object_open_as_blob(struct got_blob_object **blob,
1442     struct got_repository *repo, struct got_object_id *id,
1443     size_t blocksize)
1444 {
1445 	return open_blob(blob, repo, id, blocksize);
1446 }
1447 
1448 const struct got_error *
1449 got_object_blob_open(struct got_blob_object **blob,
1450     struct got_repository *repo, struct got_object *obj, size_t blocksize)
1451 {
1452 	return open_blob(blob, repo, got_object_get_id(obj), blocksize);
1453 }
1454 
1455 const struct got_error *
1456 got_object_blob_close(struct got_blob_object *blob)
1457 {
1458 	const struct got_error *err = NULL;
1459 	free(blob->read_buf);
1460 	if (blob->f && fclose(blob->f) == EOF)
1461 		err = got_error_from_errno("fclose");
1462 	free(blob->data);
1463 	free(blob);
1464 	return err;
1465 }
1466 
1467 void
1468 got_object_blob_rewind(struct got_blob_object *blob)
1469 {
1470 	if (blob->f)
1471 		rewind(blob->f);
1472 }
1473 
1474 char *
1475 got_object_blob_id_str(struct got_blob_object *blob, char *buf, size_t size)
1476 {
1477 	return got_sha1_digest_to_str(blob->id.sha1, buf, size);
1478 }
1479 
1480 size_t
1481 got_object_blob_get_hdrlen(struct got_blob_object *blob)
1482 {
1483 	return blob->hdrlen;
1484 }
1485 
1486 const uint8_t *
1487 got_object_blob_get_read_buf(struct got_blob_object *blob)
1488 {
1489 	return blob->read_buf;
1490 }
1491 
1492 const struct got_error *
1493 got_object_blob_read_block(size_t *outlenp, struct got_blob_object *blob)
1494 {
1495 	size_t n;
1496 
1497 	n = fread(blob->read_buf, 1, blob->blocksize, blob->f);
1498 	if (n == 0 && ferror(blob->f))
1499 		return got_ferror(blob->f, GOT_ERR_IO);
1500 	*outlenp = n;
1501 	return NULL;
1502 }
1503 
1504 const struct got_error *
1505 got_object_blob_dump_to_file(off_t *filesize, int *nlines,
1506     off_t **line_offsets, FILE *outfile, struct got_blob_object *blob)
1507 {
1508 	const struct got_error *err = NULL;
1509 	size_t n, len, hdrlen;
1510 	const uint8_t *buf;
1511 	int i;
1512 	const int alloc_chunksz = 512;
1513 	size_t nalloc = 0;
1514 	off_t off = 0, total_len = 0;
1515 
1516 	if (line_offsets)
1517 		*line_offsets = NULL;
1518 	if (filesize)
1519 		*filesize = 0;
1520 	if (nlines)
1521 		*nlines = 0;
1522 
1523 	hdrlen = got_object_blob_get_hdrlen(blob);
1524 	do {
1525 		err = got_object_blob_read_block(&len, blob);
1526 		if (err)
1527 			return err;
1528 		if (len == 0)
1529 			break;
1530 		buf = got_object_blob_get_read_buf(blob);
1531 		i = hdrlen;
1532 		if (nlines) {
1533 			if (line_offsets && *line_offsets == NULL) {
1534 				/* Have some data but perhaps no '\n'. */
1535 				*nlines = 1;
1536 				nalloc = alloc_chunksz;
1537 				*line_offsets = calloc(nalloc,
1538 				    sizeof(**line_offsets));
1539 				if (*line_offsets == NULL)
1540 					return got_error_from_errno("calloc");
1541 
1542 				/* Skip forward over end of first line. */
1543 				while (i < len) {
1544 					if (buf[i] == '\n')
1545 						break;
1546 					i++;
1547 				}
1548 			}
1549 			/* Scan '\n' offsets in remaining chunk of data. */
1550 			while (i < len) {
1551 				if (buf[i] != '\n') {
1552 					i++;
1553 					continue;
1554 				}
1555 				(*nlines)++;
1556 				if (line_offsets && nalloc < *nlines) {
1557 					size_t n = *nlines + alloc_chunksz;
1558 					off_t *o = recallocarray(*line_offsets,
1559 					    nalloc, n, sizeof(**line_offsets));
1560 					if (o == NULL) {
1561 						free(*line_offsets);
1562 						*line_offsets = NULL;
1563 						return got_error_from_errno(
1564 						    "recallocarray");
1565 					}
1566 					*line_offsets = o;
1567 					nalloc = n;
1568 				}
1569 				if (line_offsets) {
1570 					off = total_len + i - hdrlen + 1;
1571 					(*line_offsets)[*nlines - 1] = off;
1572 				}
1573 				i++;
1574 			}
1575 		}
1576 		/* Skip blob object header first time around. */
1577 		n = fwrite(buf + hdrlen, 1, len - hdrlen, outfile);
1578 		if (n != len - hdrlen)
1579 			return got_ferror(outfile, GOT_ERR_IO);
1580 		total_len += len - hdrlen;
1581 		hdrlen = 0;
1582 	} while (len != 0);
1583 
1584 	if (fflush(outfile) != 0)
1585 		return got_error_from_errno("fflush");
1586 	rewind(outfile);
1587 
1588 	if (filesize)
1589 		*filesize = total_len;
1590 
1591 	return NULL;
1592 }
1593 
1594 static const struct got_error *
1595 request_packed_tag(struct got_tag_object **tag, struct got_pack *pack,
1596     int pack_idx, struct got_object_id *id)
1597 {
1598 	const struct got_error *err = NULL;
1599 
1600 	err = got_privsep_send_tag_req(pack->privsep_child->ibuf, -1, id,
1601 	    pack_idx);
1602 	if (err)
1603 		return err;
1604 
1605 	return got_privsep_recv_tag(tag, pack->privsep_child->ibuf);
1606 }
1607 
1608 static const struct got_error *
1609 read_packed_tag_privsep(struct got_tag_object **tag,
1610     struct got_pack *pack, struct got_packidx *packidx, int idx,
1611     struct got_object_id *id)
1612 {
1613 	const struct got_error *err = NULL;
1614 
1615 	if (pack->privsep_child)
1616 		return request_packed_tag(tag, pack, idx, id);
1617 
1618 	err = start_pack_privsep_child(pack, packidx);
1619 	if (err)
1620 		return err;
1621 
1622 	return request_packed_tag(tag, pack, idx, id);
1623 }
1624 
1625 static const struct got_error *
1626 request_tag(struct got_tag_object **tag, struct got_repository *repo,
1627     int fd, struct got_object_id *id)
1628 {
1629 	const struct got_error *err = NULL;
1630 	struct imsgbuf *ibuf;
1631 
1632 	ibuf = repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_TAG].ibuf;
1633 
1634 	err = got_privsep_send_tag_req(ibuf, fd, id, -1);
1635 	if (err)
1636 		return err;
1637 
1638 	return got_privsep_recv_tag(tag, ibuf);
1639 }
1640 
1641 static const struct got_error *
1642 read_tag_privsep(struct got_tag_object **tag, int obj_fd,
1643     struct got_object_id *id, struct got_repository *repo)
1644 {
1645 	const struct got_error *err;
1646 	int imsg_fds[2];
1647 	pid_t pid;
1648 	struct imsgbuf *ibuf;
1649 
1650 	if (repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_TAG].imsg_fd != -1)
1651 		return request_tag(tag, repo, obj_fd, id);
1652 
1653 	ibuf = calloc(1, sizeof(*ibuf));
1654 	if (ibuf == NULL)
1655 		return got_error_from_errno("calloc");
1656 
1657 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1) {
1658 		err = got_error_from_errno("socketpair");
1659 		free(ibuf);
1660 		return err;
1661 	}
1662 
1663 	pid = fork();
1664 	if (pid == -1) {
1665 		err = got_error_from_errno("fork");
1666 		free(ibuf);
1667 		return err;
1668 	}
1669 	else if (pid == 0) {
1670 		got_privsep_exec_child(imsg_fds, GOT_PATH_PROG_READ_TAG,
1671 		    repo->path);
1672 		/* not reached */
1673 	}
1674 
1675 	if (close(imsg_fds[1]) == -1) {
1676 		err = got_error_from_errno("close");
1677 		free(ibuf);
1678 		return err;
1679 	}
1680 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_TAG].imsg_fd =
1681 	    imsg_fds[0];
1682 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_TAG].pid = pid;
1683 	imsg_init(ibuf, imsg_fds[0]);
1684 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_TAG].ibuf = ibuf;
1685 
1686 	return request_tag(tag, repo, obj_fd, id);
1687 }
1688 
1689 static const struct got_error *
1690 open_tag(struct got_tag_object **tag, struct got_repository *repo,
1691     struct got_object_id *id, int check_cache)
1692 {
1693 	const struct got_error *err = NULL;
1694 	struct got_packidx *packidx = NULL;
1695 	int idx;
1696 	char *path_packfile = NULL;
1697 	struct got_object *obj = NULL;
1698 	int obj_type = GOT_OBJ_TYPE_ANY;
1699 
1700 	if (check_cache) {
1701 		*tag = got_repo_get_cached_tag(repo, id);
1702 		if (*tag != NULL) {
1703 			(*tag)->refcnt++;
1704 			return NULL;
1705 		}
1706 	} else
1707 		*tag = NULL;
1708 
1709 	err = got_repo_search_packidx(&packidx, &idx, repo, id);
1710 	if (err == NULL) {
1711 		struct got_pack *pack = NULL;
1712 
1713 		err = got_packidx_get_packfile_path(&path_packfile,
1714 		    packidx->path_packidx);
1715 		if (err)
1716 			return err;
1717 
1718 		pack = got_repo_get_cached_pack(repo, path_packfile);
1719 		if (pack == NULL) {
1720 			err = got_repo_cache_pack(&pack, repo, path_packfile,
1721 			    packidx);
1722 			if (err)
1723 				goto done;
1724 		}
1725 
1726 		/* Beware of "lightweight" tags: Check object type first. */
1727 		err = read_packed_object_privsep(&obj, repo, pack, packidx,
1728 		    idx, id);
1729 		if (err)
1730 			goto done;
1731 		obj_type = obj->type;
1732 		got_object_close(obj);
1733 		if (obj_type != GOT_OBJ_TYPE_TAG) {
1734 			err = got_error(GOT_ERR_OBJ_TYPE);
1735 			goto done;
1736 		}
1737 		err = read_packed_tag_privsep(tag, pack, packidx, idx, id);
1738 	} else if (err->code == GOT_ERR_NO_OBJ) {
1739 		int fd;
1740 
1741 		err = got_object_open_loose_fd(&fd, id, repo);
1742 		if (err)
1743 			return err;
1744 		err = got_object_read_header_privsep(&obj, id, repo, fd);
1745 		if (err)
1746 			return err;
1747 		obj_type = obj->type;
1748 		got_object_close(obj);
1749 		if (obj_type != GOT_OBJ_TYPE_TAG)
1750 			return got_error(GOT_ERR_OBJ_TYPE);
1751 
1752 		err = got_object_open_loose_fd(&fd, id, repo);
1753 		if (err)
1754 			return err;
1755 		err = read_tag_privsep(tag, fd, id, repo);
1756 	}
1757 
1758 	if (err == NULL) {
1759 		(*tag)->refcnt++;
1760 		err = got_repo_cache_tag(repo, id, *tag);
1761 	}
1762 done:
1763 	free(path_packfile);
1764 	return err;
1765 }
1766 
1767 const struct got_error *
1768 got_object_open_as_tag(struct got_tag_object **tag,
1769     struct got_repository *repo, struct got_object_id *id)
1770 {
1771 	*tag = got_repo_get_cached_tag(repo, id);
1772 	if (*tag != NULL) {
1773 		(*tag)->refcnt++;
1774 		return NULL;
1775 	}
1776 
1777 	return open_tag(tag, repo, id, 0);
1778 }
1779 
1780 const struct got_error *
1781 got_object_tag_open(struct got_tag_object **tag,
1782     struct got_repository *repo, struct got_object *obj)
1783 {
1784 	return open_tag(tag, repo, got_object_get_id(obj), 1);
1785 }
1786 
1787 const char *
1788 got_object_tag_get_name(struct got_tag_object *tag)
1789 {
1790 	return tag->tag;
1791 }
1792 
1793 int
1794 got_object_tag_get_object_type(struct got_tag_object *tag)
1795 {
1796 	return tag->obj_type;
1797 }
1798 
1799 struct got_object_id *
1800 got_object_tag_get_object_id(struct got_tag_object *tag)
1801 {
1802 	return &tag->id;
1803 }
1804 
1805 time_t
1806 got_object_tag_get_tagger_time(struct got_tag_object *tag)
1807 {
1808 	return tag->tagger_time;
1809 }
1810 
1811 time_t
1812 got_object_tag_get_tagger_gmtoff(struct got_tag_object *tag)
1813 {
1814 	return tag->tagger_gmtoff;
1815 }
1816 
1817 const char *
1818 got_object_tag_get_tagger(struct got_tag_object *tag)
1819 {
1820 	return tag->tagger;
1821 }
1822 
1823 const char *
1824 got_object_tag_get_message(struct got_tag_object *tag)
1825 {
1826 	return tag->tagmsg;
1827 }
1828 
1829 static struct got_tree_entry *
1830 find_entry_by_name(struct got_tree_object *tree, const char *name, size_t len)
1831 {
1832 	int i;
1833 
1834 	/* Note that tree entries are sorted in strncmp() order. */
1835 	for (i = 0; i < tree->nentries; i++) {
1836 		struct got_tree_entry *te = &tree->entries[i];
1837 		int cmp = strncmp(te->name, name, len);
1838 		if (cmp < 0)
1839 			continue;
1840 		if (cmp > 0)
1841 			break;
1842 		if (te->name[len] == '\0')
1843 			return te;
1844 	}
1845 	return NULL;
1846 }
1847 
1848 struct got_tree_entry *
1849 got_object_tree_find_entry(struct got_tree_object *tree, const char *name)
1850 {
1851 	return find_entry_by_name(tree, name, strlen(name));
1852 }
1853 
1854 const struct got_error *
1855 got_object_tree_find_path(struct got_object_id **id, mode_t *mode,
1856     struct got_repository *repo, struct got_tree_object *tree,
1857     const char *path)
1858 {
1859 	const struct got_error *err = NULL;
1860 	struct got_tree_object *subtree = NULL;
1861 	struct got_tree_entry *te = NULL;
1862 	const char *seg, *s;
1863 	size_t seglen;
1864 
1865 	*id = NULL;
1866 
1867 	s = path;
1868 	while (s[0] == '/')
1869 		s++;
1870 	seg = s;
1871 	seglen = 0;
1872 	subtree = tree;
1873 	while (*s) {
1874 		struct got_tree_object *next_tree;
1875 
1876 		if (*s != '/') {
1877 			s++;
1878 			seglen++;
1879 			if (*s)
1880 				continue;
1881 		}
1882 
1883 		te = find_entry_by_name(subtree, seg, seglen);
1884 		if (te == NULL) {
1885 			err = got_error_path(path, GOT_ERR_NO_TREE_ENTRY);
1886 			goto done;
1887 		}
1888 
1889 		if (*s == '\0')
1890 			break;
1891 
1892 		seg = s + 1;
1893 		seglen = 0;
1894 		s++;
1895 		if (*s) {
1896 			err = got_object_open_as_tree(&next_tree, repo,
1897 			    &te->id);
1898 			te = NULL;
1899 			if (err)
1900 				goto done;
1901 			if (subtree != tree)
1902 				got_object_tree_close(subtree);
1903 			subtree = next_tree;
1904 		}
1905 	}
1906 
1907 	if (te) {
1908 		*id = got_object_id_dup(&te->id);
1909 		if (*id == NULL)
1910 			return got_error_from_errno("got_object_id_dup");
1911 		if (mode)
1912 			*mode = te->mode;
1913 	} else
1914 		err = got_error_path(path, GOT_ERR_NO_TREE_ENTRY);
1915 done:
1916 	if (subtree && subtree != tree)
1917 		got_object_tree_close(subtree);
1918 	return err;
1919 }
1920 const struct got_error *
1921 got_object_id_by_path(struct got_object_id **id, struct got_repository *repo,
1922     struct got_object_id *commit_id, const char *path)
1923 {
1924 	const struct got_error *err = NULL;
1925 	struct got_commit_object *commit = NULL;
1926 	struct got_tree_object *tree = NULL;
1927 
1928 	*id = NULL;
1929 
1930 	err = got_object_open_as_commit(&commit, repo, commit_id);
1931 	if (err)
1932 		goto done;
1933 
1934 	/* Handle opening of root of commit's tree. */
1935 	if (got_path_is_root_dir(path)) {
1936 		*id = got_object_id_dup(commit->tree_id);
1937 		if (*id == NULL)
1938 			err = got_error_from_errno("got_object_id_dup");
1939 	} else {
1940 		err = got_object_open_as_tree(&tree, repo, commit->tree_id);
1941 		if (err)
1942 			goto done;
1943 		err = got_object_tree_find_path(id, NULL, repo, tree, path);
1944 	}
1945 done:
1946 	if (commit)
1947 		got_object_commit_close(commit);
1948 	if (tree)
1949 		got_object_tree_close(tree);
1950 	return err;
1951 }
1952 
1953 /*
1954  * Normalize file mode bits to avoid false positive tree entry differences
1955  * in case tree entries have unexpected mode bits set.
1956  */
1957 static mode_t
1958 normalize_mode_for_comparison(mode_t mode)
1959 {
1960 	/*
1961 	 * For directories, the only relevant bit is the IFDIR bit.
1962 	 * This allows us to detect paths changing from a directory
1963 	 * to a file and vice versa.
1964 	 */
1965 	if (S_ISDIR(mode))
1966 		return mode & S_IFDIR;
1967 
1968 	/*
1969 	 * For symlinks, the only relevant bit is the IFLNK bit.
1970 	 * This allows us to detect paths changing from a symlinks
1971 	 * to a file or directory and vice versa.
1972 	 */
1973 	if (S_ISLNK(mode))
1974 		return mode & S_IFLNK;
1975 
1976 	/* For files, the only change we care about is the executable bit. */
1977 	return mode & S_IXUSR;
1978 }
1979 
1980 const struct got_error *
1981 got_object_tree_path_changed(int *changed,
1982     struct got_tree_object *tree01, struct got_tree_object *tree02,
1983     const char *path, struct got_repository *repo)
1984 {
1985 	const struct got_error *err = NULL;
1986 	struct got_tree_object *tree1 = NULL, *tree2 = NULL;
1987 	struct got_tree_entry *te1 = NULL, *te2 = NULL;
1988 	const char *seg, *s;
1989 	size_t seglen;
1990 
1991 	*changed = 0;
1992 
1993 	/* We not do support comparing the root path. */
1994 	if (got_path_is_root_dir(path))
1995 		return got_error_path(path, GOT_ERR_BAD_PATH);
1996 
1997 	tree1 = tree01;
1998 	tree2 = tree02;
1999 	s = path;
2000 	while (*s == '/')
2001 		s++;
2002 	seg = s;
2003 	seglen = 0;
2004 	while (*s) {
2005 		struct got_tree_object *next_tree1, *next_tree2;
2006 		mode_t mode1, mode2;
2007 
2008 		if (*s != '/') {
2009 			s++;
2010 			seglen++;
2011 			if (*s)
2012 				continue;
2013 		}
2014 
2015 		te1 = find_entry_by_name(tree1, seg, seglen);
2016 		if (te1 == NULL) {
2017 			err = got_error(GOT_ERR_NO_OBJ);
2018 			goto done;
2019 		}
2020 
2021 		if (tree2)
2022 			te2 = find_entry_by_name(tree2, seg, seglen);
2023 
2024 		if (te2) {
2025 			mode1 = normalize_mode_for_comparison(te1->mode);
2026 			mode2 = normalize_mode_for_comparison(te2->mode);
2027 			if (mode1 != mode2) {
2028 				*changed = 1;
2029 				goto done;
2030 			}
2031 
2032 			if (got_object_id_cmp(&te1->id, &te2->id) == 0) {
2033 				*changed = 0;
2034 				goto done;
2035 			}
2036 		}
2037 
2038 		if (*s == '\0') { /* final path element */
2039 			*changed = 1;
2040 			goto done;
2041 		}
2042 
2043 		seg = s + 1;
2044 		s++;
2045 		seglen = 0;
2046 		if (*s) {
2047 			err = got_object_open_as_tree(&next_tree1, repo,
2048 			    &te1->id);
2049 			te1 = NULL;
2050 			if (err)
2051 				goto done;
2052 			if (tree1 != tree01)
2053 				got_object_tree_close(tree1);
2054 			tree1 = next_tree1;
2055 
2056 			if (te2) {
2057 				err = got_object_open_as_tree(&next_tree2, repo,
2058 				    &te2->id);
2059 				te2 = NULL;
2060 				if (err)
2061 					goto done;
2062 				if (tree2 != tree02)
2063 					got_object_tree_close(tree2);
2064 				tree2 = next_tree2;
2065 			} else if (tree2) {
2066 				if (tree2 != tree02)
2067 					got_object_tree_close(tree2);
2068 				tree2 = NULL;
2069 			}
2070 		}
2071 	}
2072 done:
2073 	if (tree1 && tree1 != tree01)
2074 		got_object_tree_close(tree1);
2075 	if (tree2 && tree2 != tree02)
2076 		got_object_tree_close(tree2);
2077 	return err;
2078 }
2079 
2080 const struct got_error *
2081 got_object_tree_entry_dup(struct got_tree_entry **new_te,
2082     struct got_tree_entry *te)
2083 {
2084 	const struct got_error *err = NULL;
2085 
2086 	*new_te = calloc(1, sizeof(**new_te));
2087 	if (*new_te == NULL)
2088 		return got_error_from_errno("calloc");
2089 
2090 	(*new_te)->mode = te->mode;
2091 	memcpy((*new_te)->name, te->name, sizeof((*new_te)->name));
2092 	memcpy(&(*new_te)->id, &te->id, sizeof((*new_te)->id));
2093 	return err;
2094 }
2095 
2096 int
2097 got_object_tree_entry_is_submodule(struct got_tree_entry *te)
2098 {
2099 	return (te->mode & S_IFMT) == (S_IFDIR | S_IFLNK);
2100 }
2101 
2102 int
2103 got_object_tree_entry_is_symlink(struct got_tree_entry *te)
2104 {
2105 	/* S_IFDIR check avoids confusing symlinks with submodules. */
2106 	return ((te->mode & (S_IFDIR | S_IFLNK)) == S_IFLNK);
2107 }
2108 
2109 static const struct got_error *
2110 resolve_symlink(char **link_target, const char *path,
2111     struct got_object_id *commit_id, struct got_repository *repo)
2112 {
2113 	const struct got_error *err = NULL;
2114 	char buf[PATH_MAX];
2115 	char *name, *parent_path = NULL;
2116 	struct got_object_id *tree_obj_id = NULL;
2117 	struct got_tree_object *tree = NULL;
2118 	struct got_tree_entry *te = NULL;
2119 
2120 	*link_target = NULL;
2121 
2122 	if (strlcpy(buf, path, sizeof(buf)) >= sizeof(buf))
2123 		return got_error(GOT_ERR_NO_SPACE);
2124 
2125 	name = basename(buf);
2126 	if (name == NULL)
2127 		return got_error_from_errno2("basename", path);
2128 
2129 	err = got_path_dirname(&parent_path, path);
2130 	if (err)
2131 		return err;
2132 
2133 	err = got_object_id_by_path(&tree_obj_id, repo, commit_id,
2134 	    parent_path);
2135 	if (err) {
2136 		if (err->code == GOT_ERR_NO_TREE_ENTRY) {
2137 			/* Display the complete path in error message. */
2138 			err = got_error_path(path, err->code);
2139 		}
2140 		goto done;
2141 	}
2142 
2143 	err = got_object_open_as_tree(&tree, repo, tree_obj_id);
2144 	if (err)
2145 		goto done;
2146 
2147 	te = got_object_tree_find_entry(tree, name);
2148 	if (te == NULL) {
2149 		err = got_error_path(path, GOT_ERR_NO_TREE_ENTRY);
2150 		goto done;
2151 	}
2152 
2153 	if (got_object_tree_entry_is_symlink(te)) {
2154 		err = got_tree_entry_get_symlink_target(link_target, te, repo);
2155 		if (err)
2156 			goto done;
2157 		if (!got_path_is_absolute(*link_target)) {
2158 			char *abspath;
2159 			if (asprintf(&abspath, "%s/%s", parent_path,
2160 			    *link_target) == -1) {
2161 				err = got_error_from_errno("asprintf");
2162 				goto done;
2163 			}
2164 			free(*link_target);
2165 			*link_target = malloc(PATH_MAX);
2166 			if (*link_target == NULL) {
2167 				err = got_error_from_errno("malloc");
2168 				goto done;
2169 			}
2170 			err = got_canonpath(abspath, *link_target, PATH_MAX);
2171 			free(abspath);
2172 			if (err)
2173 				goto done;
2174 		}
2175 	}
2176 done:
2177 	free(tree_obj_id);
2178 	if (tree)
2179 		got_object_tree_close(tree);
2180 	if (err) {
2181 		free(*link_target);
2182 		*link_target = NULL;
2183 	}
2184 	return err;
2185 }
2186 
2187 const struct got_error *
2188 got_object_resolve_symlinks(char **link_target, const char *path,
2189     struct got_object_id *commit_id, struct got_repository *repo)
2190 {
2191 	const struct got_error *err = NULL;
2192 	char *next_target = NULL;
2193 	int max_recursion = 40; /* matches Git */
2194 
2195 	*link_target = NULL;
2196 
2197 	do {
2198 		err = resolve_symlink(&next_target,
2199 		    *link_target ? *link_target : path, commit_id, repo);
2200 		if (err)
2201 			break;
2202 		if (next_target) {
2203 			free(*link_target);
2204 			if (--max_recursion == 0) {
2205 				err = got_error_path(path, GOT_ERR_RECURSION);
2206 				*link_target = NULL;
2207 				break;
2208 			}
2209 			*link_target = next_target;
2210 		}
2211 	} while (next_target);
2212 
2213 	return err;
2214 }
2215 
2216 const struct got_error *
2217 got_traverse_packed_commits(struct got_object_id_queue *traversed_commits,
2218     struct got_object_id *commit_id, const char *path,
2219     struct got_repository *repo)
2220 {
2221 	const struct got_error *err = NULL;
2222 	struct got_pack *pack = NULL;
2223 	struct got_packidx *packidx = NULL;
2224 	char *path_packfile = NULL;
2225 	struct got_commit_object *changed_commit = NULL;
2226 	struct got_object_id *changed_commit_id = NULL;
2227 	int idx;
2228 
2229 	err = got_repo_search_packidx(&packidx, &idx, repo, commit_id);
2230 	if (err) {
2231 		if (err->code != GOT_ERR_NO_OBJ)
2232 			return err;
2233 		return NULL;
2234 	}
2235 
2236 	err = got_packidx_get_packfile_path(&path_packfile,
2237 	    packidx->path_packidx);
2238 	if (err)
2239 		return err;
2240 
2241 	pack = got_repo_get_cached_pack(repo, path_packfile);
2242 	if (pack == NULL) {
2243 		err = got_repo_cache_pack(&pack, repo, path_packfile, packidx);
2244 		if (err)
2245 			goto done;
2246 	}
2247 
2248 	if (pack->privsep_child == NULL) {
2249 		err = start_pack_privsep_child(pack, packidx);
2250 		if (err)
2251 			goto done;
2252 	}
2253 
2254 	err = got_privsep_send_commit_traversal_request(
2255 	    pack->privsep_child->ibuf, commit_id, idx, path);
2256 	if (err)
2257 		goto done;
2258 
2259 	err = got_privsep_recv_traversed_commits(&changed_commit,
2260 	    &changed_commit_id, traversed_commits, pack->privsep_child->ibuf);
2261 	if (err)
2262 		goto done;
2263 
2264 	if (changed_commit) {
2265 		/*
2266 		 * Cache the commit in which the path was changed.
2267 		 * This commit might be opened again soon.
2268 		 */
2269 		changed_commit->refcnt++;
2270 		err = got_repo_cache_commit(repo, changed_commit_id,
2271 		    changed_commit);
2272 		got_object_commit_close(changed_commit);
2273 	}
2274 done:
2275 	free(path_packfile);
2276 	free(changed_commit_id);
2277 	return err;
2278 }