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Date:: Fri Oct 15 09:10:14 2021 UTC
Message:: cache raw objects in order to speed up gotadmin pack
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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);
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 static const struct got_error *
170 request_packed_object_raw(uint8_t **outbuf, off_t *size, size_t *hdrlen,
171     int outfd, struct got_pack *pack, int idx, struct got_object_id *id)
172 {
173 	const struct got_error *err = NULL;
174 	struct imsgbuf *ibuf = pack->privsep_child->ibuf;
175 	int outfd_child;
176 	int basefd, accumfd; /* temporary files for delta application */
177 
178 	basefd = got_opentempfd();
179 	if (basefd == -1)
180 		return got_error_from_errno("got_opentempfd");
181 
182 	accumfd = got_opentempfd();
183 	if (accumfd == -1) {
184 		close(basefd);
185 		return got_error_from_errno("got_opentempfd");
186 	}
187 
188 	outfd_child = dup(outfd);
189 	if (outfd_child == -1) {
190 		err = got_error_from_errno("dup");
191 		close(basefd);
192 		close(accumfd);
193 		return err;
194 	}
195 
196 	err = got_privsep_send_packed_raw_obj_req(ibuf, idx, id);
197 	if (err) {
198 		close(basefd);
199 		close(accumfd);
200 		close(outfd_child);
201 		return err;
202 	}
203 
204 	err = got_privsep_send_raw_obj_outfd(ibuf, outfd_child);
205 	if (err) {
206 		close(basefd);
207 		close(accumfd);
208 		return err;
209 	}
210 
211 
212 	err = got_privsep_send_tmpfd(pack->privsep_child->ibuf,
213 	    basefd);
214 	if (err) {
215 		close(accumfd);
216 		return err;
217 	}
218 
219 	err = got_privsep_send_tmpfd(pack->privsep_child->ibuf,
220 	    accumfd);
221 	if (err)
222 		return err;
223 
224 	err = got_privsep_recv_raw_obj(outbuf, size, hdrlen, ibuf);
225 	if (err)
226 		return err;
227 
228 	return NULL;
229 }
230 
231 static void
232 set_max_datasize(void)
233 {
234 	struct rlimit rl;
235 
236 	if (getrlimit(RLIMIT_DATA, &rl) != 0)
237 		return;
238 
239 	rl.rlim_cur = rl.rlim_max;
240 	setrlimit(RLIMIT_DATA, &rl);
241 }
242 
243 static const struct got_error *
244 start_pack_privsep_child(struct got_pack *pack, struct got_packidx *packidx)
245 {
246 	const struct got_error *err = NULL;
247 	int imsg_fds[2];
248 	pid_t pid;
249 	struct imsgbuf *ibuf;
250 
251 	ibuf = calloc(1, sizeof(*ibuf));
252 	if (ibuf == NULL)
253 		return got_error_from_errno("calloc");
254 
255 	pack->privsep_child = calloc(1, sizeof(*pack->privsep_child));
256 	if (pack->privsep_child == NULL) {
257 		err = got_error_from_errno("calloc");
258 		free(ibuf);
259 		return err;
260 	}
261 
262 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1) {
263 		err = got_error_from_errno("socketpair");
264 		goto done;
265 	}
266 
267 	pid = fork();
268 	if (pid == -1) {
269 		err = got_error_from_errno("fork");
270 		goto done;
271 	} else if (pid == 0) {
272 		set_max_datasize();
273 		got_privsep_exec_child(imsg_fds, GOT_PATH_PROG_READ_PACK,
274 		    pack->path_packfile);
275 		/* not reached */
276 	}
277 
278 	if (close(imsg_fds[1]) == -1)
279 		return got_error_from_errno("close");
280 	pack->privsep_child->imsg_fd = imsg_fds[0];
281 	pack->privsep_child->pid = pid;
282 	imsg_init(ibuf, imsg_fds[0]);
283 	pack->privsep_child->ibuf = ibuf;
284 
285 	err = got_privsep_init_pack_child(ibuf, pack, packidx);
286 	if (err) {
287 		const struct got_error *child_err;
288 		err = got_privsep_send_stop(pack->privsep_child->imsg_fd);
289 		child_err = got_privsep_wait_for_child(
290 		    pack->privsep_child->pid);
291 		if (child_err && err == NULL)
292 			err = child_err;
293 	}
294 done:
295 	if (err) {
296 		free(ibuf);
297 		free(pack->privsep_child);
298 		pack->privsep_child = NULL;
299 	}
300 	return err;
301 }
302 
303 static const struct got_error *
304 read_packed_object_privsep(struct got_object **obj,
305     struct got_repository *repo, struct got_pack *pack,
306     struct got_packidx *packidx, int idx, struct got_object_id *id)
307 {
308 	const struct got_error *err = NULL;
309 
310 	if (pack->privsep_child == NULL) {
311 		err = start_pack_privsep_child(pack, packidx);
312 		if (err)
313 			return err;
314 	}
315 
316 	return request_packed_object(obj, pack, idx, id);
317 }
318 
319 static const struct got_error *
320 read_packed_object_raw_privsep(uint8_t **outbuf, off_t *size, size_t *hdrlen,
321     int outfd, struct got_pack *pack, struct got_packidx *packidx, int idx,
322     struct got_object_id *id)
323 {
324 	const struct got_error *err = NULL;
325 
326 	if (pack->privsep_child == NULL) {
327 		err = start_pack_privsep_child(pack, packidx);
328 		if (err)
329 			return err;
330 	}
331 
332 	return request_packed_object_raw(outbuf, size, hdrlen, outfd, pack,
333 	    idx, id);
334 }
335 
336 const struct got_error *
337 got_object_open_packed(struct got_object **obj, struct got_object_id *id,
338     struct got_repository *repo)
339 {
340 	const struct got_error *err = NULL;
341 	struct got_pack *pack = NULL;
342 	struct got_packidx *packidx = NULL;
343 	int idx;
344 	char *path_packfile;
345 
346 	err = got_repo_search_packidx(&packidx, &idx, repo, id);
347 	if (err)
348 		return err;
349 
350 	err = got_packidx_get_packfile_path(&path_packfile,
351 	    packidx->path_packidx);
352 	if (err)
353 		return err;
354 
355 	pack = got_repo_get_cached_pack(repo, path_packfile);
356 	if (pack == NULL) {
357 		err = got_repo_cache_pack(&pack, repo, path_packfile, packidx);
358 		if (err)
359 			goto done;
360 	}
361 
362 	err = read_packed_object_privsep(obj, repo, pack, packidx, idx, id);
363 	if (err)
364 		goto done;
365 done:
366 	free(path_packfile);
367 	return err;
368 }
369 
370 static const struct got_error *
371 request_object(struct got_object **obj, struct got_object_id *id,
372     struct got_repository *repo, int fd)
373 {
374 	const struct got_error *err = NULL;
375 	struct imsgbuf *ibuf;
376 
377 	ibuf = repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_OBJECT].ibuf;
378 
379 	err = got_privsep_send_obj_req(ibuf, fd, id);
380 	if (err)
381 		return err;
382 
383 	return got_privsep_recv_obj(obj, ibuf);
384 }
385 
386 static const struct got_error *
387 request_raw_object(uint8_t **outbuf, off_t *size, size_t *hdrlen, int outfd,
388     struct got_object_id *id, struct got_repository *repo, int infd)
389 {
390 	const struct got_error *err = NULL;
391 	struct imsgbuf *ibuf;
392 	int outfd_child;
393 
394 	ibuf = repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_OBJECT].ibuf;
395 
396 	outfd_child = dup(outfd);
397 	if (outfd_child == -1)
398 		return got_error_from_errno("dup");
399 
400 	err = got_privsep_send_raw_obj_req(ibuf, infd, id);
401 	if (err)
402 		return err;
403 
404 	err = got_privsep_send_raw_obj_outfd(ibuf, outfd_child);
405 	if (err)
406 		return err;
407 
408 	return got_privsep_recv_raw_obj(outbuf, size, hdrlen, ibuf);
409 }
410 
411 static const struct got_error *
412 start_read_object_child(struct got_repository *repo)
413 {
414 	const struct got_error *err = NULL;
415 	int imsg_fds[2];
416 	pid_t pid;
417 	struct imsgbuf *ibuf;
418 
419 	ibuf = calloc(1, sizeof(*ibuf));
420 	if (ibuf == NULL)
421 		return got_error_from_errno("calloc");
422 
423 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1) {
424 		err = got_error_from_errno("socketpair");
425 		free(ibuf);
426 		return err;
427 	}
428 
429 	pid = fork();
430 	if (pid == -1) {
431 		err = got_error_from_errno("fork");
432 		free(ibuf);
433 		return err;
434 	}
435 	else if (pid == 0) {
436 		got_privsep_exec_child(imsg_fds, GOT_PATH_PROG_READ_OBJECT,
437 		    repo->path);
438 		/* not reached */
439 	}
440 
441 	if (close(imsg_fds[1]) == -1) {
442 		err = got_error_from_errno("close");
443 		free(ibuf);
444 		return err;
445 	}
446 
447 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_OBJECT].imsg_fd =
448 	    imsg_fds[0];
449 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_OBJECT].pid = pid;
450 	imsg_init(ibuf, imsg_fds[0]);
451 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_OBJECT].ibuf = ibuf;
452 
453 	return NULL;
454 }
455 
456 const struct got_error *
457 got_object_read_header_privsep(struct got_object **obj,
458     struct got_object_id *id, struct got_repository *repo, int obj_fd)
459 {
460 	const struct got_error *err;
461 
462 	if (repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_OBJECT].imsg_fd != -1)
463 		return request_object(obj, id, repo, obj_fd);
464 
465 	err = start_read_object_child(repo);
466 	if (err) {
467 		close(obj_fd);
468 		return err;
469 	}
470 
471 	return request_object(obj, id, repo, obj_fd);
472 }
473 
474 static const struct got_error *
475 read_object_raw_privsep(uint8_t **outbuf, off_t *size, size_t *hdrlen,
476     int outfd, struct got_object_id *id, struct got_repository *repo,
477     int obj_fd)
478 {
479 	const struct got_error *err;
480 
481 	if (repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_OBJECT].imsg_fd != -1)
482 		return request_raw_object(outbuf, size, hdrlen, outfd, id,
483 		    repo, obj_fd);
484 
485 	err = start_read_object_child(repo);
486 	if (err)
487 		return err;
488 
489 	return request_raw_object(outbuf, size, hdrlen, outfd, id, repo,
490 	    obj_fd);
491 }
492 
493 const struct got_error *
494 got_object_open(struct got_object **obj, struct got_repository *repo,
495     struct got_object_id *id)
496 {
497 	const struct got_error *err = NULL;
498 	int fd;
499 
500 	*obj = got_repo_get_cached_object(repo, id);
501 	if (*obj != NULL) {
502 		(*obj)->refcnt++;
503 		return NULL;
504 	}
505 
506 	err = got_object_open_packed(obj, id, repo);
507 	if (err && err->code != GOT_ERR_NO_OBJ)
508 		return err;
509 	if (*obj) {
510 		(*obj)->refcnt++;
511 		return got_repo_cache_object(repo, id, *obj);
512 	}
513 
514 	err = got_object_open_loose_fd(&fd, id, repo);
515 	if (err) {
516 		if (err->code == GOT_ERR_ERRNO && errno == ENOENT)
517 			err = got_error_no_obj(id);
518 		return err;
519 	}
520 
521 	err = got_object_read_header_privsep(obj, id, repo, fd);
522 	if (err)
523 		return err;
524 
525 	memcpy((*obj)->id.sha1, id->sha1, SHA1_DIGEST_LENGTH);
526 
527 	(*obj)->refcnt++;
528 	return got_repo_cache_object(repo, id, *obj);
529 }
530 
531 /* *outfd must be initialized to -1 by caller */
532 const struct got_error *
533 got_object_raw_open(struct got_raw_object **obj, int *outfd,
534     struct got_repository *repo, struct got_object_id *id, size_t blocksize)
535 {
536 	const struct got_error *err = NULL;
537 	struct got_packidx *packidx = NULL;
538 	int idx;
539 	uint8_t *outbuf = NULL;
540 	off_t size = 0;
541 	size_t hdrlen = 0;
542 	char *path_packfile = NULL;
543 
544 	*obj = got_repo_get_cached_raw_object(repo, id);
545 	if (*obj != NULL) {
546 		(*obj)->refcnt++;
547 		return NULL;
548 	}
549 
550 	if (*outfd == -1) {
551 		*outfd = got_opentempfd();
552 		if (*outfd == -1)
553 			return got_error_from_errno("got_opentempfd");
554 	}
555 
556 	err = got_repo_search_packidx(&packidx, &idx, repo, id);
557 	if (err == NULL) {
558 		struct got_pack *pack = NULL;
559 
560 		err = got_packidx_get_packfile_path(&path_packfile,
561 		    packidx->path_packidx);
562 		if (err)
563 			goto done;
564 
565 		pack = got_repo_get_cached_pack(repo, path_packfile);
566 		if (pack == NULL) {
567 			err = got_repo_cache_pack(&pack, repo, path_packfile,
568 			    packidx);
569 			if (err)
570 				goto done;
571 		}
572 		err = read_packed_object_raw_privsep(&outbuf, &size, &hdrlen,
573 		    *outfd, pack, packidx, idx, id);
574 		if (err)
575 			goto done;
576 	} else if (err->code == GOT_ERR_NO_OBJ) {
577 		int fd;
578 
579 		err = got_object_open_loose_fd(&fd, id, repo);
580 		if (err)
581 			goto done;
582 		err = read_object_raw_privsep(&outbuf, &size, &hdrlen, *outfd,
583 		    id, repo, fd);
584 		if (err)
585 			goto done;
586 	}
587 
588 	*obj = calloc(1, sizeof(**obj));
589 	if (*obj == NULL) {
590 		err = got_error_from_errno("calloc");
591 		goto done;
592 	}
593 
594 	(*obj)->read_buf = malloc(blocksize);
595 	if ((*obj)->read_buf == NULL) {
596 		err = got_error_from_errno("malloc");
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 	(*obj)->blocksize = blocksize;
630 	err = got_repo_cache_raw_object(repo, id, *obj);
631 done:
632 	free(path_packfile);
633 	if (err) {
634 		if (*obj) {
635 			got_object_raw_close(*obj);
636 			*obj = NULL;
637 		}
638 		free(outbuf);
639 	} else
640 		(*obj)->refcnt++;
641 	return err;
642 }
643 
644 void
645 got_object_raw_rewind(struct got_raw_object *obj)
646 {
647 	if (obj->f)
648 		rewind(obj->f);
649 }
650 
651 size_t
652 got_object_raw_get_hdrlen(struct got_raw_object *obj)
653 {
654 	return obj->hdrlen;
655 }
656 
657 const uint8_t *
658 got_object_raw_get_read_buf(struct got_raw_object *obj)
659 {
660 	return obj->read_buf;
661 }
662 
663 const struct got_error *
664 got_object_raw_read_block(size_t *outlenp, struct got_raw_object *obj)
665 {
666 	size_t n;
667 
668 	n = fread(obj->read_buf, 1, obj->blocksize, obj->f);
669 	if (n == 0 && ferror(obj->f))
670 		return got_ferror(obj->f, GOT_ERR_IO);
671 	*outlenp = n;
672 	return NULL;
673 }
674 
675 const struct got_error *
676 got_object_open_by_id_str(struct got_object **obj, struct got_repository *repo,
677     const char *id_str)
678 {
679 	struct got_object_id id;
680 
681 	if (!got_parse_sha1_digest(id.sha1, id_str))
682 		return got_error_path(id_str, GOT_ERR_BAD_OBJ_ID_STR);
683 
684 	return got_object_open(obj, repo, &id);
685 }
686 
687 const struct got_error *
688 got_object_resolve_id_str(struct got_object_id **id,
689     struct got_repository *repo, const char *id_str)
690 {
691 	const struct got_error *err = NULL;
692 	struct got_object *obj;
693 
694 	err = got_object_open_by_id_str(&obj, repo, id_str);
695 	if (err)
696 		return err;
697 
698 	*id = got_object_id_dup(got_object_get_id(obj));
699 	got_object_close(obj);
700 	if (*id == NULL)
701 		return got_error_from_errno("got_object_id_dup");
702 
703 	return NULL;
704 }
705 
706 static const struct got_error *
707 request_packed_commit(struct got_commit_object **commit, struct got_pack *pack,
708     int pack_idx, struct got_object_id *id)
709 {
710 	const struct got_error *err = NULL;
711 
712 	err = got_privsep_send_commit_req(pack->privsep_child->ibuf, -1, id,
713 	    pack_idx);
714 	if (err)
715 		return err;
716 
717 	err = got_privsep_recv_commit(commit, pack->privsep_child->ibuf);
718 	if (err)
719 		return err;
720 
721 	(*commit)->flags |= GOT_COMMIT_FLAG_PACKED;
722 	return NULL;
723 }
724 
725 static const struct got_error *
726 read_packed_commit_privsep(struct got_commit_object **commit,
727     struct got_pack *pack, struct got_packidx *packidx, int idx,
728     struct got_object_id *id)
729 {
730 	const struct got_error *err = NULL;
731 
732 	if (pack->privsep_child)
733 		return request_packed_commit(commit, pack, idx, id);
734 
735 	err = start_pack_privsep_child(pack, packidx);
736 	if (err)
737 		return err;
738 
739 	return request_packed_commit(commit, pack, idx, id);
740 }
741 
742 static const struct got_error *
743 request_commit(struct got_commit_object **commit, struct got_repository *repo,
744     int fd, struct got_object_id *id)
745 {
746 	const struct got_error *err = NULL;
747 	struct imsgbuf *ibuf;
748 
749 	ibuf = repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_COMMIT].ibuf;
750 
751 	err = got_privsep_send_commit_req(ibuf, fd, id, -1);
752 	if (err)
753 		return err;
754 
755 	return got_privsep_recv_commit(commit, ibuf);
756 }
757 
758 static const struct got_error *
759 read_commit_privsep(struct got_commit_object **commit, int obj_fd,
760     struct got_object_id *id, struct got_repository *repo)
761 {
762 	const struct got_error *err;
763 	int imsg_fds[2];
764 	pid_t pid;
765 	struct imsgbuf *ibuf;
766 
767 	if (repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_COMMIT].imsg_fd != -1)
768 		return request_commit(commit, repo, obj_fd, id);
769 
770 	ibuf = calloc(1, sizeof(*ibuf));
771 	if (ibuf == NULL)
772 		return got_error_from_errno("calloc");
773 
774 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1) {
775 		err = got_error_from_errno("socketpair");
776 		free(ibuf);
777 		return err;
778 	}
779 
780 	pid = fork();
781 	if (pid == -1) {
782 		err = got_error_from_errno("fork");
783 		free(ibuf);
784 		return err;
785 	}
786 	else if (pid == 0) {
787 		got_privsep_exec_child(imsg_fds, GOT_PATH_PROG_READ_COMMIT,
788 		    repo->path);
789 		/* not reached */
790 	}
791 
792 	if (close(imsg_fds[1]) == -1) {
793 		err = got_error_from_errno("close");
794 		free(ibuf);
795 		return err;
796 	}
797 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_COMMIT].imsg_fd =
798 	    imsg_fds[0];
799 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_COMMIT].pid = pid;
800 	imsg_init(ibuf, imsg_fds[0]);
801 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_COMMIT].ibuf = ibuf;
802 
803 	return request_commit(commit, repo, obj_fd, id);
804 }
805 
806 
807 static const struct got_error *
808 open_commit(struct got_commit_object **commit,
809     struct got_repository *repo, struct got_object_id *id, int check_cache)
810 {
811 	const struct got_error *err = NULL;
812 	struct got_packidx *packidx = NULL;
813 	int idx;
814 	char *path_packfile = NULL;
815 
816 	if (check_cache) {
817 		*commit = got_repo_get_cached_commit(repo, id);
818 		if (*commit != NULL) {
819 			(*commit)->refcnt++;
820 			return NULL;
821 		}
822 	} else
823 		*commit = NULL;
824 
825 	err = got_repo_search_packidx(&packidx, &idx, repo, id);
826 	if (err == NULL) {
827 		struct got_pack *pack = NULL;
828 
829 		err = got_packidx_get_packfile_path(&path_packfile,
830 		    packidx->path_packidx);
831 		if (err)
832 			return err;
833 
834 		pack = got_repo_get_cached_pack(repo, path_packfile);
835 		if (pack == NULL) {
836 			err = got_repo_cache_pack(&pack, repo, path_packfile,
837 			    packidx);
838 			if (err)
839 				goto done;
840 		}
841 		err = read_packed_commit_privsep(commit, pack,
842 		    packidx, idx, id);
843 	} else if (err->code == GOT_ERR_NO_OBJ) {
844 		int fd;
845 
846 		err = got_object_open_loose_fd(&fd, id, repo);
847 		if (err)
848 			return err;
849 		err = read_commit_privsep(commit, fd, id, repo);
850 	}
851 
852 	if (err == NULL) {
853 		(*commit)->refcnt++;
854 		err = got_repo_cache_commit(repo, id, *commit);
855 	}
856 done:
857 	free(path_packfile);
858 	return err;
859 }
860 
861 const struct got_error *
862 got_object_open_as_commit(struct got_commit_object **commit,
863     struct got_repository *repo, struct got_object_id *id)
864 {
865 	*commit = got_repo_get_cached_commit(repo, id);
866 	if (*commit != NULL) {
867 		(*commit)->refcnt++;
868 		return NULL;
869 	}
870 
871 	return open_commit(commit, repo, id, 0);
872 }
873 
874 const struct got_error *
875 got_object_commit_open(struct got_commit_object **commit,
876     struct got_repository *repo, struct got_object *obj)
877 {
878 	return open_commit(commit, repo, got_object_get_id(obj), 1);
879 }
880 
881 const struct got_error *
882 got_object_qid_alloc(struct got_object_qid **qid, struct got_object_id *id)
883 {
884 	const struct got_error *err = NULL;
885 
886 	*qid = calloc(1, sizeof(**qid));
887 	if (*qid == NULL)
888 		return got_error_from_errno("calloc");
889 
890 	(*qid)->id = got_object_id_dup(id);
891 	if ((*qid)->id == NULL) {
892 		err = got_error_from_errno("got_object_id_dup");
893 		got_object_qid_free(*qid);
894 		*qid = NULL;
895 		return err;
896 	}
897 
898 	return NULL;
899 }
900 
901 const struct got_error *
902 got_object_id_queue_copy(const struct got_object_id_queue *src,
903     struct got_object_id_queue *dest)
904 {
905 	const struct got_error *err;
906 	struct got_object_qid *qid;
907 
908 	STAILQ_FOREACH(qid, src, entry) {
909 		struct got_object_qid *new;
910 		/*
911 		 * Deep-copy the object ID only. Let the caller deal
912 		 * with setting up the new->data pointer if needed.
913 		 */
914 		err = got_object_qid_alloc(&new, qid->id); 
915 		if (err) {
916 			got_object_id_queue_free(dest);
917 			return err;
918 		}
919 		STAILQ_INSERT_TAIL(dest, new, entry);
920 	}
921 
922 	return NULL;
923 }
924 
925 static const struct got_error *
926 request_packed_tree(struct got_tree_object **tree, struct got_pack *pack,
927     int pack_idx, struct got_object_id *id)
928 {
929 	const struct got_error *err = NULL;
930 
931 	err = got_privsep_send_tree_req(pack->privsep_child->ibuf, -1, id,
932 	    pack_idx);
933 	if (err)
934 		return err;
935 
936 	return got_privsep_recv_tree(tree, pack->privsep_child->ibuf);
937 }
938 
939 static const struct got_error *
940 read_packed_tree_privsep(struct got_tree_object **tree,
941     struct got_pack *pack, struct got_packidx *packidx, int idx,
942     struct got_object_id *id)
943 {
944 	const struct got_error *err = NULL;
945 
946 	if (pack->privsep_child)
947 		return request_packed_tree(tree, pack, idx, id);
948 
949 	err = start_pack_privsep_child(pack, packidx);
950 	if (err)
951 		return err;
952 
953 	return request_packed_tree(tree, pack, idx, id);
954 }
955 
956 static const struct got_error *
957 request_tree(struct got_tree_object **tree, struct got_repository *repo,
958     int fd, struct got_object_id *id)
959 {
960 	const struct got_error *err = NULL;
961 	struct imsgbuf *ibuf;
962 
963 	ibuf = repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_TREE].ibuf;
964 
965 	err = got_privsep_send_tree_req(ibuf, fd, id, -1);
966 	if (err)
967 		return err;
968 
969 	return got_privsep_recv_tree(tree, ibuf);
970 }
971 
972 const struct got_error *
973 read_tree_privsep(struct got_tree_object **tree, int obj_fd,
974     struct got_object_id *id, struct got_repository *repo)
975 {
976 	const struct got_error *err;
977 	int imsg_fds[2];
978 	pid_t pid;
979 	struct imsgbuf *ibuf;
980 
981 	if (repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_TREE].imsg_fd != -1)
982 		return request_tree(tree, repo, obj_fd, id);
983 
984 	ibuf = calloc(1, sizeof(*ibuf));
985 	if (ibuf == NULL)
986 		return got_error_from_errno("calloc");
987 
988 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1) {
989 		err = got_error_from_errno("socketpair");
990 		free(ibuf);
991 		return err;
992 	}
993 
994 	pid = fork();
995 	if (pid == -1) {
996 		err = got_error_from_errno("fork");
997 		free(ibuf);
998 		return err;
999 	}
1000 	else if (pid == 0) {
1001 		got_privsep_exec_child(imsg_fds, GOT_PATH_PROG_READ_TREE,
1002 		    repo->path);
1003 		/* not reached */
1004 	}
1005 
1006 	if (close(imsg_fds[1]) == -1) {
1007 		err = got_error_from_errno("close");
1008 		free(ibuf);
1009 		return err;
1010 	}
1011 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_TREE].imsg_fd =
1012 	    imsg_fds[0];
1013 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_TREE].pid = pid;
1014 	imsg_init(ibuf, imsg_fds[0]);
1015 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_TREE].ibuf = ibuf;
1016 
1017 
1018 	return request_tree(tree, repo, obj_fd, id);
1019 }
1020 
1021 static const struct got_error *
1022 open_tree(struct got_tree_object **tree, struct got_repository *repo,
1023     struct got_object_id *id, int check_cache)
1024 {
1025 	const struct got_error *err = NULL;
1026 	struct got_packidx *packidx = NULL;
1027 	int idx;
1028 	char *path_packfile = NULL;
1029 
1030 	if (check_cache) {
1031 		*tree = got_repo_get_cached_tree(repo, id);
1032 		if (*tree != NULL) {
1033 			(*tree)->refcnt++;
1034 			return NULL;
1035 		}
1036 	} else
1037 		*tree = NULL;
1038 
1039 	err = got_repo_search_packidx(&packidx, &idx, repo, id);
1040 	if (err == NULL) {
1041 		struct got_pack *pack = NULL;
1042 
1043 		err = got_packidx_get_packfile_path(&path_packfile,
1044 		    packidx->path_packidx);
1045 		if (err)
1046 			return err;
1047 
1048 		pack = got_repo_get_cached_pack(repo, path_packfile);
1049 		if (pack == NULL) {
1050 			err = got_repo_cache_pack(&pack, repo, path_packfile,
1051 			    packidx);
1052 			if (err)
1053 				goto done;
1054 		}
1055 		err = read_packed_tree_privsep(tree, pack,
1056 		    packidx, idx, id);
1057 	} else if (err->code == GOT_ERR_NO_OBJ) {
1058 		int fd;
1059 
1060 		err = got_object_open_loose_fd(&fd, id, repo);
1061 		if (err)
1062 			return err;
1063 		err = read_tree_privsep(tree, fd, id, repo);
1064 	}
1065 
1066 	if (err == NULL) {
1067 		(*tree)->refcnt++;
1068 		err = got_repo_cache_tree(repo, id, *tree);
1069 	}
1070 done:
1071 	free(path_packfile);
1072 	return err;
1073 }
1074 
1075 const struct got_error *
1076 got_object_open_as_tree(struct got_tree_object **tree,
1077     struct got_repository *repo, struct got_object_id *id)
1078 {
1079 	*tree = got_repo_get_cached_tree(repo, id);
1080 	if (*tree != NULL) {
1081 		(*tree)->refcnt++;
1082 		return NULL;
1083 	}
1084 
1085 	return open_tree(tree, repo, id, 0);
1086 }
1087 
1088 const struct got_error *
1089 got_object_tree_open(struct got_tree_object **tree,
1090     struct got_repository *repo, struct got_object *obj)
1091 {
1092 	return open_tree(tree, repo, got_object_get_id(obj), 1);
1093 }
1094 
1095 int
1096 got_object_tree_get_nentries(struct got_tree_object *tree)
1097 {
1098 	return tree->nentries;
1099 }
1100 
1101 struct got_tree_entry *
1102 got_object_tree_get_first_entry(struct got_tree_object *tree)
1103 {
1104 	return got_object_tree_get_entry(tree, 0);
1105 }
1106 
1107 struct got_tree_entry *
1108 got_object_tree_get_last_entry(struct got_tree_object *tree)
1109 {
1110 	return got_object_tree_get_entry(tree, tree->nentries - 1);
1111 }
1112 
1113 struct got_tree_entry *
1114 got_object_tree_get_entry(struct got_tree_object *tree, int i)
1115 {
1116 	if (i < 0 || i >= tree->nentries)
1117 		return NULL;
1118 	return &tree->entries[i];
1119 }
1120 
1121 mode_t
1122 got_tree_entry_get_mode(struct got_tree_entry *te)
1123 {
1124 	return te->mode;
1125 }
1126 
1127 const char *
1128 got_tree_entry_get_name(struct got_tree_entry *te)
1129 {
1130 	return &te->name[0];
1131 }
1132 
1133 struct got_object_id *
1134 got_tree_entry_get_id(struct got_tree_entry *te)
1135 {
1136 	return &te->id;
1137 }
1138 
1139 const struct got_error *
1140 got_object_blob_read_to_str(char **s, struct got_blob_object *blob)
1141 {
1142 	const struct got_error *err = NULL;
1143 	size_t len, totlen, hdrlen, offset;
1144 
1145 	*s = NULL;
1146 
1147 	hdrlen = got_object_blob_get_hdrlen(blob);
1148 	totlen = 0;
1149 	offset = 0;
1150 	do {
1151 		char *p;
1152 
1153 		err = got_object_blob_read_block(&len, blob);
1154 		if (err)
1155 			return err;
1156 
1157 		if (len == 0)
1158 			break;
1159 
1160 		totlen += len - hdrlen;
1161 		p = realloc(*s, totlen + 1);
1162 		if (p == NULL) {
1163 			err = got_error_from_errno("realloc");
1164 			free(*s);
1165 			*s = NULL;
1166 			return err;
1167 		}
1168 		*s = p;
1169 		/* Skip blob object header first time around. */
1170 		memcpy(*s + offset,
1171 		    got_object_blob_get_read_buf(blob) + hdrlen, len - hdrlen);
1172 		hdrlen = 0;
1173 		offset = totlen;
1174 	} while (len > 0);
1175 
1176 	(*s)[totlen] = '\0';
1177 	return NULL;
1178 }
1179 
1180 const struct got_error *
1181 got_tree_entry_get_symlink_target(char **link_target, struct got_tree_entry *te,
1182     struct got_repository *repo)
1183 {
1184 	const struct got_error *err = NULL;
1185 	struct got_blob_object *blob = NULL;
1186 
1187 	*link_target = NULL;
1188 
1189 	if (!got_object_tree_entry_is_symlink(te))
1190 		return got_error(GOT_ERR_TREE_ENTRY_TYPE);
1191 
1192 	err = got_object_open_as_blob(&blob, repo,
1193 	    got_tree_entry_get_id(te), PATH_MAX);
1194 	if (err)
1195 		return err;
1196 
1197 	err = got_object_blob_read_to_str(link_target, blob);
1198 	got_object_blob_close(blob);
1199 	if (err) {
1200 		free(*link_target);
1201 		*link_target = NULL;
1202 	}
1203 	return err;
1204 }
1205 
1206 int
1207 got_tree_entry_get_index(struct got_tree_entry *te)
1208 {
1209 	return te->idx;
1210 }
1211 
1212 struct got_tree_entry *
1213 got_tree_entry_get_next(struct got_tree_object *tree,
1214     struct got_tree_entry *te)
1215 {
1216 	return got_object_tree_get_entry(tree, te->idx + 1);
1217 }
1218 
1219 struct got_tree_entry *
1220 got_tree_entry_get_prev(struct got_tree_object *tree,
1221     struct got_tree_entry *te)
1222 {
1223 	return got_object_tree_get_entry(tree, te->idx - 1);
1224 }
1225 
1226 static const struct got_error *
1227 request_packed_blob(uint8_t **outbuf, size_t *size, size_t *hdrlen, int outfd,
1228     struct got_pack *pack, struct got_packidx *packidx, int idx,
1229     struct got_object_id *id)
1230 {
1231 	const struct got_error *err = NULL;
1232 	int outfd_child;
1233 	int basefd, accumfd; /* temporary files for delta application */
1234 
1235 	basefd = got_opentempfd();
1236 	if (basefd == -1)
1237 		return got_error_from_errno("got_opentempfd");
1238 	accumfd = got_opentempfd();
1239 	if (accumfd == -1)
1240 		return got_error_from_errno("got_opentempfd");
1241 
1242 	outfd_child = dup(outfd);
1243 	if (outfd_child == -1)
1244 		return got_error_from_errno("dup");
1245 
1246 	err = got_privsep_send_blob_req(pack->privsep_child->ibuf, -1, id, idx);
1247 	if (err)
1248 		return err;
1249 
1250 	err = got_privsep_send_blob_outfd(pack->privsep_child->ibuf,
1251 	    outfd_child);
1252 	if (err) {
1253 		close(basefd);
1254 		close(accumfd);
1255 		return err;
1256 	}
1257 
1258 	err = got_privsep_send_tmpfd(pack->privsep_child->ibuf,
1259 	    basefd);
1260 	if (err) {
1261 		close(accumfd);
1262 		return err;
1263 	}
1264 
1265 	err = got_privsep_send_tmpfd(pack->privsep_child->ibuf,
1266 	    accumfd);
1267 	if (err)
1268 		return err;
1269 
1270 	err = got_privsep_recv_blob(outbuf, size, hdrlen,
1271 	    pack->privsep_child->ibuf);
1272 	if (err)
1273 		return err;
1274 
1275 	if (lseek(outfd, SEEK_SET, 0) == -1)
1276 		err = got_error_from_errno("lseek");
1277 
1278 	return err;
1279 }
1280 
1281 static const struct got_error *
1282 read_packed_blob_privsep(uint8_t **outbuf, size_t *size, size_t *hdrlen,
1283     int outfd, struct got_pack *pack, struct got_packidx *packidx, int idx,
1284     struct got_object_id *id)
1285 {
1286 	const struct got_error *err = NULL;
1287 
1288 	if (pack->privsep_child == NULL) {
1289 		err = start_pack_privsep_child(pack, packidx);
1290 		if (err)
1291 			return err;
1292 	}
1293 
1294 	return request_packed_blob(outbuf, size, hdrlen, outfd, pack, packidx,
1295 	    idx, id);
1296 }
1297 
1298 static const struct got_error *
1299 request_blob(uint8_t **outbuf, size_t *size, size_t *hdrlen, int outfd,
1300     int infd, struct got_object_id *id, struct imsgbuf *ibuf)
1301 {
1302 	const struct got_error *err = NULL;
1303 	int outfd_child;
1304 
1305 	outfd_child = dup(outfd);
1306 	if (outfd_child == -1)
1307 		return got_error_from_errno("dup");
1308 
1309 	err = got_privsep_send_blob_req(ibuf, infd, id, -1);
1310 	if (err)
1311 		return err;
1312 
1313 	err = got_privsep_send_blob_outfd(ibuf, outfd_child);
1314 	if (err)
1315 		return err;
1316 
1317 	err = got_privsep_recv_blob(outbuf, size, hdrlen, ibuf);
1318 	if (err)
1319 		return err;
1320 
1321 	if (lseek(outfd, SEEK_SET, 0) == -1)
1322 		return got_error_from_errno("lseek");
1323 
1324 	return err;
1325 }
1326 
1327 static const struct got_error *
1328 read_blob_privsep(uint8_t **outbuf, size_t *size, size_t *hdrlen,
1329     int outfd, int infd, struct got_object_id *id, struct got_repository *repo)
1330 {
1331 	const struct got_error *err;
1332 	int imsg_fds[2];
1333 	pid_t pid;
1334 	struct imsgbuf *ibuf;
1335 
1336 	if (repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_BLOB].imsg_fd != -1) {
1337 		ibuf = repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_BLOB].ibuf;
1338 		return request_blob(outbuf, size, hdrlen, outfd, infd, id,
1339 		    ibuf);
1340 	}
1341 
1342 	ibuf = calloc(1, sizeof(*ibuf));
1343 	if (ibuf == NULL)
1344 		return got_error_from_errno("calloc");
1345 
1346 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1) {
1347 		err = got_error_from_errno("socketpair");
1348 		free(ibuf);
1349 		return err;
1350 	}
1351 
1352 	pid = fork();
1353 	if (pid == -1) {
1354 		err = got_error_from_errno("fork");
1355 		free(ibuf);
1356 		return err;
1357 	}
1358 	else if (pid == 0) {
1359 		got_privsep_exec_child(imsg_fds, GOT_PATH_PROG_READ_BLOB,
1360 		    repo->path);
1361 		/* not reached */
1362 	}
1363 
1364 	if (close(imsg_fds[1]) == -1) {
1365 		err = got_error_from_errno("close");
1366 		free(ibuf);
1367 		return err;
1368 	}
1369 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_BLOB].imsg_fd =
1370 	    imsg_fds[0];
1371 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_BLOB].pid = pid;
1372 	imsg_init(ibuf, imsg_fds[0]);
1373 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_BLOB].ibuf = ibuf;
1374 
1375 	return request_blob(outbuf, size, hdrlen, outfd, infd, id, ibuf);
1376 }
1377 
1378 static const struct got_error *
1379 open_blob(struct got_blob_object **blob, struct got_repository *repo,
1380     struct got_object_id *id, size_t blocksize)
1381 {
1382 	const struct got_error *err = NULL;
1383 	struct got_packidx *packidx = NULL;
1384 	int idx;
1385 	char *path_packfile = NULL;
1386 	uint8_t *outbuf;
1387 	int outfd;
1388 	size_t size, hdrlen;
1389 	struct stat sb;
1390 
1391 	*blob = calloc(1, sizeof(**blob));
1392 	if (*blob == NULL)
1393 		return got_error_from_errno("calloc");
1394 
1395 	outfd = got_opentempfd();
1396 	if (outfd == -1)
1397 		return got_error_from_errno("got_opentempfd");
1398 
1399 	(*blob)->read_buf = malloc(blocksize);
1400 	if ((*blob)->read_buf == NULL) {
1401 		err = got_error_from_errno("malloc");
1402 		goto done;
1403 	}
1404 
1405 	err = got_repo_search_packidx(&packidx, &idx, repo, id);
1406 	if (err == NULL) {
1407 		struct got_pack *pack = NULL;
1408 
1409 		err = got_packidx_get_packfile_path(&path_packfile,
1410 		    packidx->path_packidx);
1411 		if (err)
1412 			goto done;
1413 
1414 		pack = got_repo_get_cached_pack(repo, path_packfile);
1415 		if (pack == NULL) {
1416 			err = got_repo_cache_pack(&pack, repo, path_packfile,
1417 			    packidx);
1418 			if (err)
1419 				goto done;
1420 		}
1421 		err = read_packed_blob_privsep(&outbuf, &size, &hdrlen, outfd,
1422 		    pack, packidx, idx, id);
1423 	} else if (err->code == GOT_ERR_NO_OBJ) {
1424 		int infd;
1425 
1426 		err = got_object_open_loose_fd(&infd, id, repo);
1427 		if (err)
1428 			goto done;
1429 		err = read_blob_privsep(&outbuf, &size, &hdrlen, outfd, infd,
1430 		    id, repo);
1431 	}
1432 	if (err)
1433 		goto done;
1434 
1435 	if (hdrlen > size) {
1436 		err = got_error(GOT_ERR_BAD_OBJ_HDR);
1437 		goto done;
1438 	}
1439 
1440 	if (outbuf) {
1441 		if (close(outfd) == -1 && err == NULL)
1442 			err = got_error_from_errno("close");
1443 		outfd = -1;
1444 		(*blob)->f = fmemopen(outbuf, size, "rb");
1445 		if ((*blob)->f == NULL) {
1446 			err = got_error_from_errno("fmemopen");
1447 			free(outbuf);
1448 			goto done;
1449 		}
1450 		(*blob)->data = outbuf;
1451 	} else {
1452 		if (fstat(outfd, &sb) == -1) {
1453 			err = got_error_from_errno("fstat");
1454 			goto done;
1455 		}
1456 
1457 		if (sb.st_size != size) {
1458 			err = got_error(GOT_ERR_PRIVSEP_LEN);
1459 			goto done;
1460 		}
1461 
1462 		(*blob)->f = fdopen(outfd, "rb");
1463 		if ((*blob)->f == NULL) {
1464 			err = got_error_from_errno("fdopen");
1465 			close(outfd);
1466 			outfd = -1;
1467 			goto done;
1468 		}
1469 	}
1470 
1471 	(*blob)->hdrlen = hdrlen;
1472 	(*blob)->blocksize = blocksize;
1473 	memcpy(&(*blob)->id.sha1, id->sha1, SHA1_DIGEST_LENGTH);
1474 
1475 done:
1476 	free(path_packfile);
1477 	if (err) {
1478 		if (*blob) {
1479 			got_object_blob_close(*blob);
1480 			*blob = NULL;
1481 		} else if (outfd != -1)
1482 			close(outfd);
1483 	}
1484 	return err;
1485 }
1486 
1487 const struct got_error *
1488 got_object_open_as_blob(struct got_blob_object **blob,
1489     struct got_repository *repo, struct got_object_id *id,
1490     size_t blocksize)
1491 {
1492 	return open_blob(blob, repo, id, blocksize);
1493 }
1494 
1495 const struct got_error *
1496 got_object_blob_open(struct got_blob_object **blob,
1497     struct got_repository *repo, struct got_object *obj, size_t blocksize)
1498 {
1499 	return open_blob(blob, repo, got_object_get_id(obj), blocksize);
1500 }
1501 
1502 const struct got_error *
1503 got_object_blob_close(struct got_blob_object *blob)
1504 {
1505 	const struct got_error *err = NULL;
1506 	free(blob->read_buf);
1507 	if (blob->f && fclose(blob->f) == EOF)
1508 		err = got_error_from_errno("fclose");
1509 	free(blob->data);
1510 	free(blob);
1511 	return err;
1512 }
1513 
1514 void
1515 got_object_blob_rewind(struct got_blob_object *blob)
1516 {
1517 	if (blob->f)
1518 		rewind(blob->f);
1519 }
1520 
1521 char *
1522 got_object_blob_id_str(struct got_blob_object *blob, char *buf, size_t size)
1523 {
1524 	return got_sha1_digest_to_str(blob->id.sha1, buf, size);
1525 }
1526 
1527 size_t
1528 got_object_blob_get_hdrlen(struct got_blob_object *blob)
1529 {
1530 	return blob->hdrlen;
1531 }
1532 
1533 const uint8_t *
1534 got_object_blob_get_read_buf(struct got_blob_object *blob)
1535 {
1536 	return blob->read_buf;
1537 }
1538 
1539 const struct got_error *
1540 got_object_blob_read_block(size_t *outlenp, struct got_blob_object *blob)
1541 {
1542 	size_t n;
1543 
1544 	n = fread(blob->read_buf, 1, blob->blocksize, blob->f);
1545 	if (n == 0 && ferror(blob->f))
1546 		return got_ferror(blob->f, GOT_ERR_IO);
1547 	*outlenp = n;
1548 	return NULL;
1549 }
1550 
1551 const struct got_error *
1552 got_object_blob_dump_to_file(off_t *filesize, int *nlines,
1553     off_t **line_offsets, FILE *outfile, struct got_blob_object *blob)
1554 {
1555 	const struct got_error *err = NULL;
1556 	size_t n, len, hdrlen;
1557 	const uint8_t *buf;
1558 	int i;
1559 	const int alloc_chunksz = 512;
1560 	size_t nalloc = 0;
1561 	off_t off = 0, total_len = 0;
1562 
1563 	if (line_offsets)
1564 		*line_offsets = NULL;
1565 	if (filesize)
1566 		*filesize = 0;
1567 	if (nlines)
1568 		*nlines = 0;
1569 
1570 	hdrlen = got_object_blob_get_hdrlen(blob);
1571 	do {
1572 		err = got_object_blob_read_block(&len, blob);
1573 		if (err)
1574 			return err;
1575 		if (len == 0)
1576 			break;
1577 		buf = got_object_blob_get_read_buf(blob);
1578 		i = hdrlen;
1579 		if (nlines) {
1580 			if (line_offsets && *line_offsets == NULL) {
1581 				/* Have some data but perhaps no '\n'. */
1582 				*nlines = 1;
1583 				nalloc = alloc_chunksz;
1584 				*line_offsets = calloc(nalloc,
1585 				    sizeof(**line_offsets));
1586 				if (*line_offsets == NULL)
1587 					return got_error_from_errno("calloc");
1588 
1589 				/* Skip forward over end of first line. */
1590 				while (i < len) {
1591 					if (buf[i] == '\n')
1592 						break;
1593 					i++;
1594 				}
1595 			}
1596 			/* Scan '\n' offsets in remaining chunk of data. */
1597 			while (i < len) {
1598 				if (buf[i] != '\n') {
1599 					i++;
1600 					continue;
1601 				}
1602 				(*nlines)++;
1603 				if (line_offsets && nalloc < *nlines) {
1604 					size_t n = *nlines + alloc_chunksz;
1605 					off_t *o = recallocarray(*line_offsets,
1606 					    nalloc, n, sizeof(**line_offsets));
1607 					if (o == NULL) {
1608 						free(*line_offsets);
1609 						*line_offsets = NULL;
1610 						return got_error_from_errno(
1611 						    "recallocarray");
1612 					}
1613 					*line_offsets = o;
1614 					nalloc = n;
1615 				}
1616 				if (line_offsets) {
1617 					off = total_len + i - hdrlen + 1;
1618 					(*line_offsets)[*nlines - 1] = off;
1619 				}
1620 				i++;
1621 			}
1622 		}
1623 		/* Skip blob object header first time around. */
1624 		n = fwrite(buf + hdrlen, 1, len - hdrlen, outfile);
1625 		if (n != len - hdrlen)
1626 			return got_ferror(outfile, GOT_ERR_IO);
1627 		total_len += len - hdrlen;
1628 		hdrlen = 0;
1629 	} while (len != 0);
1630 
1631 	if (fflush(outfile) != 0)
1632 		return got_error_from_errno("fflush");
1633 	rewind(outfile);
1634 
1635 	if (filesize)
1636 		*filesize = total_len;
1637 
1638 	return NULL;
1639 }
1640 
1641 static const struct got_error *
1642 request_packed_tag(struct got_tag_object **tag, struct got_pack *pack,
1643     int pack_idx, struct got_object_id *id)
1644 {
1645 	const struct got_error *err = NULL;
1646 
1647 	err = got_privsep_send_tag_req(pack->privsep_child->ibuf, -1, id,
1648 	    pack_idx);
1649 	if (err)
1650 		return err;
1651 
1652 	return got_privsep_recv_tag(tag, pack->privsep_child->ibuf);
1653 }
1654 
1655 static const struct got_error *
1656 read_packed_tag_privsep(struct got_tag_object **tag,
1657     struct got_pack *pack, struct got_packidx *packidx, int idx,
1658     struct got_object_id *id)
1659 {
1660 	const struct got_error *err = NULL;
1661 
1662 	if (pack->privsep_child)
1663 		return request_packed_tag(tag, pack, idx, id);
1664 
1665 	err = start_pack_privsep_child(pack, packidx);
1666 	if (err)
1667 		return err;
1668 
1669 	return request_packed_tag(tag, pack, idx, id);
1670 }
1671 
1672 static const struct got_error *
1673 request_tag(struct got_tag_object **tag, struct got_repository *repo,
1674     int fd, struct got_object_id *id)
1675 {
1676 	const struct got_error *err = NULL;
1677 	struct imsgbuf *ibuf;
1678 
1679 	ibuf = repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_TAG].ibuf;
1680 
1681 	err = got_privsep_send_tag_req(ibuf, fd, id, -1);
1682 	if (err)
1683 		return err;
1684 
1685 	return got_privsep_recv_tag(tag, ibuf);
1686 }
1687 
1688 static const struct got_error *
1689 read_tag_privsep(struct got_tag_object **tag, int obj_fd,
1690     struct got_object_id *id, struct got_repository *repo)
1691 {
1692 	const struct got_error *err;
1693 	int imsg_fds[2];
1694 	pid_t pid;
1695 	struct imsgbuf *ibuf;
1696 
1697 	if (repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_TAG].imsg_fd != -1)
1698 		return request_tag(tag, repo, obj_fd, id);
1699 
1700 	ibuf = calloc(1, sizeof(*ibuf));
1701 	if (ibuf == NULL)
1702 		return got_error_from_errno("calloc");
1703 
1704 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1) {
1705 		err = got_error_from_errno("socketpair");
1706 		free(ibuf);
1707 		return err;
1708 	}
1709 
1710 	pid = fork();
1711 	if (pid == -1) {
1712 		err = got_error_from_errno("fork");
1713 		free(ibuf);
1714 		return err;
1715 	}
1716 	else if (pid == 0) {
1717 		got_privsep_exec_child(imsg_fds, GOT_PATH_PROG_READ_TAG,
1718 		    repo->path);
1719 		/* not reached */
1720 	}
1721 
1722 	if (close(imsg_fds[1]) == -1) {
1723 		err = got_error_from_errno("close");
1724 		free(ibuf);
1725 		return err;
1726 	}
1727 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_TAG].imsg_fd =
1728 	    imsg_fds[0];
1729 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_TAG].pid = pid;
1730 	imsg_init(ibuf, imsg_fds[0]);
1731 	repo->privsep_children[GOT_REPO_PRIVSEP_CHILD_TAG].ibuf = ibuf;
1732 
1733 	return request_tag(tag, repo, obj_fd, id);
1734 }
1735 
1736 static const struct got_error *
1737 open_tag(struct got_tag_object **tag, struct got_repository *repo,
1738     struct got_object_id *id, int check_cache)
1739 {
1740 	const struct got_error *err = NULL;
1741 	struct got_packidx *packidx = NULL;
1742 	int idx;
1743 	char *path_packfile = NULL;
1744 	struct got_object *obj = NULL;
1745 	int obj_type = GOT_OBJ_TYPE_ANY;
1746 
1747 	if (check_cache) {
1748 		*tag = got_repo_get_cached_tag(repo, id);
1749 		if (*tag != NULL) {
1750 			(*tag)->refcnt++;
1751 			return NULL;
1752 		}
1753 	} else
1754 		*tag = NULL;
1755 
1756 	err = got_repo_search_packidx(&packidx, &idx, repo, id);
1757 	if (err == NULL) {
1758 		struct got_pack *pack = NULL;
1759 
1760 		err = got_packidx_get_packfile_path(&path_packfile,
1761 		    packidx->path_packidx);
1762 		if (err)
1763 			return err;
1764 
1765 		pack = got_repo_get_cached_pack(repo, path_packfile);
1766 		if (pack == NULL) {
1767 			err = got_repo_cache_pack(&pack, repo, path_packfile,
1768 			    packidx);
1769 			if (err)
1770 				goto done;
1771 		}
1772 
1773 		/* Beware of "lightweight" tags: Check object type first. */
1774 		err = read_packed_object_privsep(&obj, repo, pack, packidx,
1775 		    idx, id);
1776 		if (err)
1777 			goto done;
1778 		obj_type = obj->type;
1779 		got_object_close(obj);
1780 		if (obj_type != GOT_OBJ_TYPE_TAG) {
1781 			err = got_error(GOT_ERR_OBJ_TYPE);
1782 			goto done;
1783 		}
1784 		err = read_packed_tag_privsep(tag, pack, packidx, idx, id);
1785 	} else if (err->code == GOT_ERR_NO_OBJ) {
1786 		int fd;
1787 
1788 		err = got_object_open_loose_fd(&fd, id, repo);
1789 		if (err)
1790 			return err;
1791 		err = got_object_read_header_privsep(&obj, id, repo, fd);
1792 		if (err)
1793 			return err;
1794 		obj_type = obj->type;
1795 		got_object_close(obj);
1796 		if (obj_type != GOT_OBJ_TYPE_TAG)
1797 			return got_error(GOT_ERR_OBJ_TYPE);
1798 
1799 		err = got_object_open_loose_fd(&fd, id, repo);
1800 		if (err)
1801 			return err;
1802 		err = read_tag_privsep(tag, fd, id, repo);
1803 	}
1804 
1805 	if (err == NULL) {
1806 		(*tag)->refcnt++;
1807 		err = got_repo_cache_tag(repo, id, *tag);
1808 	}
1809 done:
1810 	free(path_packfile);
1811 	return err;
1812 }
1813 
1814 const struct got_error *
1815 got_object_open_as_tag(struct got_tag_object **tag,
1816     struct got_repository *repo, struct got_object_id *id)
1817 {
1818 	*tag = got_repo_get_cached_tag(repo, id);
1819 	if (*tag != NULL) {
1820 		(*tag)->refcnt++;
1821 		return NULL;
1822 	}
1823 
1824 	return open_tag(tag, repo, id, 0);
1825 }
1826 
1827 const struct got_error *
1828 got_object_tag_open(struct got_tag_object **tag,
1829     struct got_repository *repo, struct got_object *obj)
1830 {
1831 	return open_tag(tag, repo, got_object_get_id(obj), 1);
1832 }
1833 
1834 const char *
1835 got_object_tag_get_name(struct got_tag_object *tag)
1836 {
1837 	return tag->tag;
1838 }
1839 
1840 int
1841 got_object_tag_get_object_type(struct got_tag_object *tag)
1842 {
1843 	return tag->obj_type;
1844 }
1845 
1846 struct got_object_id *
1847 got_object_tag_get_object_id(struct got_tag_object *tag)
1848 {
1849 	return &tag->id;
1850 }
1851 
1852 time_t
1853 got_object_tag_get_tagger_time(struct got_tag_object *tag)
1854 {
1855 	return tag->tagger_time;
1856 }
1857 
1858 time_t
1859 got_object_tag_get_tagger_gmtoff(struct got_tag_object *tag)
1860 {
1861 	return tag->tagger_gmtoff;
1862 }
1863 
1864 const char *
1865 got_object_tag_get_tagger(struct got_tag_object *tag)
1866 {
1867 	return tag->tagger;
1868 }
1869 
1870 const char *
1871 got_object_tag_get_message(struct got_tag_object *tag)
1872 {
1873 	return tag->tagmsg;
1874 }
1875 
1876 static struct got_tree_entry *
1877 find_entry_by_name(struct got_tree_object *tree, const char *name, size_t len)
1878 {
1879 	int i;
1880 
1881 	/* Note that tree entries are sorted in strncmp() order. */
1882 	for (i = 0; i < tree->nentries; i++) {
1883 		struct got_tree_entry *te = &tree->entries[i];
1884 		int cmp = strncmp(te->name, name, len);
1885 		if (cmp < 0)
1886 			continue;
1887 		if (cmp > 0)
1888 			break;
1889 		if (te->name[len] == '\0')
1890 			return te;
1891 	}
1892 	return NULL;
1893 }
1894 
1895 struct got_tree_entry *
1896 got_object_tree_find_entry(struct got_tree_object *tree, const char *name)
1897 {
1898 	return find_entry_by_name(tree, name, strlen(name));
1899 }
1900 
1901 const struct got_error *
1902 got_object_tree_find_path(struct got_object_id **id, mode_t *mode,
1903     struct got_repository *repo, struct got_tree_object *tree,
1904     const char *path)
1905 {
1906 	const struct got_error *err = NULL;
1907 	struct got_tree_object *subtree = NULL;
1908 	struct got_tree_entry *te = NULL;
1909 	const char *seg, *s;
1910 	size_t seglen;
1911 
1912 	*id = NULL;
1913 
1914 	s = path;
1915 	while (s[0] == '/')
1916 		s++;
1917 	seg = s;
1918 	seglen = 0;
1919 	subtree = tree;
1920 	while (*s) {
1921 		struct got_tree_object *next_tree;
1922 
1923 		if (*s != '/') {
1924 			s++;
1925 			seglen++;
1926 			if (*s)
1927 				continue;
1928 		}
1929 
1930 		te = find_entry_by_name(subtree, seg, seglen);
1931 		if (te == NULL) {
1932 			err = got_error_path(path, GOT_ERR_NO_TREE_ENTRY);
1933 			goto done;
1934 		}
1935 
1936 		if (*s == '\0')
1937 			break;
1938 
1939 		seg = s + 1;
1940 		seglen = 0;
1941 		s++;
1942 		if (*s) {
1943 			err = got_object_open_as_tree(&next_tree, repo,
1944 			    &te->id);
1945 			te = NULL;
1946 			if (err)
1947 				goto done;
1948 			if (subtree != tree)
1949 				got_object_tree_close(subtree);
1950 			subtree = next_tree;
1951 		}
1952 	}
1953 
1954 	if (te) {
1955 		*id = got_object_id_dup(&te->id);
1956 		if (*id == NULL)
1957 			return got_error_from_errno("got_object_id_dup");
1958 		if (mode)
1959 			*mode = te->mode;
1960 	} else
1961 		err = got_error_path(path, GOT_ERR_NO_TREE_ENTRY);
1962 done:
1963 	if (subtree && subtree != tree)
1964 		got_object_tree_close(subtree);
1965 	return err;
1966 }
1967 const struct got_error *
1968 got_object_id_by_path(struct got_object_id **id, struct got_repository *repo,
1969     struct got_object_id *commit_id, const char *path)
1970 {
1971 	const struct got_error *err = NULL;
1972 	struct got_commit_object *commit = NULL;
1973 	struct got_tree_object *tree = NULL;
1974 
1975 	*id = NULL;
1976 
1977 	err = got_object_open_as_commit(&commit, repo, commit_id);
1978 	if (err)
1979 		goto done;
1980 
1981 	/* Handle opening of root of commit's tree. */
1982 	if (got_path_is_root_dir(path)) {
1983 		*id = got_object_id_dup(commit->tree_id);
1984 		if (*id == NULL)
1985 			err = got_error_from_errno("got_object_id_dup");
1986 	} else {
1987 		err = got_object_open_as_tree(&tree, repo, commit->tree_id);
1988 		if (err)
1989 			goto done;
1990 		err = got_object_tree_find_path(id, NULL, repo, tree, path);
1991 	}
1992 done:
1993 	if (commit)
1994 		got_object_commit_close(commit);
1995 	if (tree)
1996 		got_object_tree_close(tree);
1997 	return err;
1998 }
1999 
2000 /*
2001  * Normalize file mode bits to avoid false positive tree entry differences
2002  * in case tree entries have unexpected mode bits set.
2003  */
2004 static mode_t
2005 normalize_mode_for_comparison(mode_t mode)
2006 {
2007 	/*
2008 	 * For directories, the only relevant bit is the IFDIR bit.
2009 	 * This allows us to detect paths changing from a directory
2010 	 * to a file and vice versa.
2011 	 */
2012 	if (S_ISDIR(mode))
2013 		return mode & S_IFDIR;
2014 
2015 	/*
2016 	 * For symlinks, the only relevant bit is the IFLNK bit.
2017 	 * This allows us to detect paths changing from a symlinks
2018 	 * to a file or directory and vice versa.
2019 	 */
2020 	if (S_ISLNK(mode))
2021 		return mode & S_IFLNK;
2022 
2023 	/* For files, the only change we care about is the executable bit. */
2024 	return mode & S_IXUSR;
2025 }
2026 
2027 const struct got_error *
2028 got_object_tree_path_changed(int *changed,
2029     struct got_tree_object *tree01, struct got_tree_object *tree02,
2030     const char *path, struct got_repository *repo)
2031 {
2032 	const struct got_error *err = NULL;
2033 	struct got_tree_object *tree1 = NULL, *tree2 = NULL;
2034 	struct got_tree_entry *te1 = NULL, *te2 = NULL;
2035 	const char *seg, *s;
2036 	size_t seglen;
2037 
2038 	*changed = 0;
2039 
2040 	/* We not do support comparing the root path. */
2041 	if (got_path_is_root_dir(path))
2042 		return got_error_path(path, GOT_ERR_BAD_PATH);
2043 
2044 	tree1 = tree01;
2045 	tree2 = tree02;
2046 	s = path;
2047 	while (*s == '/')
2048 		s++;
2049 	seg = s;
2050 	seglen = 0;
2051 	while (*s) {
2052 		struct got_tree_object *next_tree1, *next_tree2;
2053 		mode_t mode1, mode2;
2054 
2055 		if (*s != '/') {
2056 			s++;
2057 			seglen++;
2058 			if (*s)
2059 				continue;
2060 		}
2061 
2062 		te1 = find_entry_by_name(tree1, seg, seglen);
2063 		if (te1 == NULL) {
2064 			err = got_error(GOT_ERR_NO_OBJ);
2065 			goto done;
2066 		}
2067 
2068 		if (tree2)
2069 			te2 = find_entry_by_name(tree2, seg, seglen);
2070 
2071 		if (te2) {
2072 			mode1 = normalize_mode_for_comparison(te1->mode);
2073 			mode2 = normalize_mode_for_comparison(te2->mode);
2074 			if (mode1 != mode2) {
2075 				*changed = 1;
2076 				goto done;
2077 			}
2078 
2079 			if (got_object_id_cmp(&te1->id, &te2->id) == 0) {
2080 				*changed = 0;
2081 				goto done;
2082 			}
2083 		}
2084 
2085 		if (*s == '\0') { /* final path element */
2086 			*changed = 1;
2087 			goto done;
2088 		}
2089 
2090 		seg = s + 1;
2091 		s++;
2092 		seglen = 0;
2093 		if (*s) {
2094 			err = got_object_open_as_tree(&next_tree1, repo,
2095 			    &te1->id);
2096 			te1 = NULL;
2097 			if (err)
2098 				goto done;
2099 			if (tree1 != tree01)
2100 				got_object_tree_close(tree1);
2101 			tree1 = next_tree1;
2102 
2103 			if (te2) {
2104 				err = got_object_open_as_tree(&next_tree2, repo,
2105 				    &te2->id);
2106 				te2 = NULL;
2107 				if (err)
2108 					goto done;
2109 				if (tree2 != tree02)
2110 					got_object_tree_close(tree2);
2111 				tree2 = next_tree2;
2112 			} else if (tree2) {
2113 				if (tree2 != tree02)
2114 					got_object_tree_close(tree2);
2115 				tree2 = NULL;
2116 			}
2117 		}
2118 	}
2119 done:
2120 	if (tree1 && tree1 != tree01)
2121 		got_object_tree_close(tree1);
2122 	if (tree2 && tree2 != tree02)
2123 		got_object_tree_close(tree2);
2124 	return err;
2125 }
2126 
2127 const struct got_error *
2128 got_object_tree_entry_dup(struct got_tree_entry **new_te,
2129     struct got_tree_entry *te)
2130 {
2131 	const struct got_error *err = NULL;
2132 
2133 	*new_te = calloc(1, sizeof(**new_te));
2134 	if (*new_te == NULL)
2135 		return got_error_from_errno("calloc");
2136 
2137 	(*new_te)->mode = te->mode;
2138 	memcpy((*new_te)->name, te->name, sizeof((*new_te)->name));
2139 	memcpy(&(*new_te)->id, &te->id, sizeof((*new_te)->id));
2140 	return err;
2141 }
2142 
2143 int
2144 got_object_tree_entry_is_submodule(struct got_tree_entry *te)
2145 {
2146 	return (te->mode & S_IFMT) == (S_IFDIR | S_IFLNK);
2147 }
2148 
2149 int
2150 got_object_tree_entry_is_symlink(struct got_tree_entry *te)
2151 {
2152 	/* S_IFDIR check avoids confusing symlinks with submodules. */
2153 	return ((te->mode & (S_IFDIR | S_IFLNK)) == S_IFLNK);
2154 }
2155 
2156 static const struct got_error *
2157 resolve_symlink(char **link_target, const char *path,
2158     struct got_object_id *commit_id, struct got_repository *repo)
2159 {
2160 	const struct got_error *err = NULL;
2161 	char buf[PATH_MAX];
2162 	char *name, *parent_path = NULL;
2163 	struct got_object_id *tree_obj_id = NULL;
2164 	struct got_tree_object *tree = NULL;
2165 	struct got_tree_entry *te = NULL;
2166 
2167 	*link_target = NULL;
2168 
2169 	if (strlcpy(buf, path, sizeof(buf)) >= sizeof(buf))
2170 		return got_error(GOT_ERR_NO_SPACE);
2171 
2172 	name = basename(buf);
2173 	if (name == NULL)
2174 		return got_error_from_errno2("basename", path);
2175 
2176 	err = got_path_dirname(&parent_path, path);
2177 	if (err)
2178 		return err;
2179 
2180 	err = got_object_id_by_path(&tree_obj_id, repo, commit_id,
2181 	    parent_path);
2182 	if (err) {
2183 		if (err->code == GOT_ERR_NO_TREE_ENTRY) {
2184 			/* Display the complete path in error message. */
2185 			err = got_error_path(path, err->code);
2186 		}
2187 		goto done;
2188 	}
2189 
2190 	err = got_object_open_as_tree(&tree, repo, tree_obj_id);
2191 	if (err)
2192 		goto done;
2193 
2194 	te = got_object_tree_find_entry(tree, name);
2195 	if (te == NULL) {
2196 		err = got_error_path(path, GOT_ERR_NO_TREE_ENTRY);
2197 		goto done;
2198 	}
2199 
2200 	if (got_object_tree_entry_is_symlink(te)) {
2201 		err = got_tree_entry_get_symlink_target(link_target, te, repo);
2202 		if (err)
2203 			goto done;
2204 		if (!got_path_is_absolute(*link_target)) {
2205 			char *abspath;
2206 			if (asprintf(&abspath, "%s/%s", parent_path,
2207 			    *link_target) == -1) {
2208 				err = got_error_from_errno("asprintf");
2209 				goto done;
2210 			}
2211 			free(*link_target);
2212 			*link_target = malloc(PATH_MAX);
2213 			if (*link_target == NULL) {
2214 				err = got_error_from_errno("malloc");
2215 				goto done;
2216 			}
2217 			err = got_canonpath(abspath, *link_target, PATH_MAX);
2218 			free(abspath);
2219 			if (err)
2220 				goto done;
2221 		}
2222 	}
2223 done:
2224 	free(tree_obj_id);
2225 	if (tree)
2226 		got_object_tree_close(tree);
2227 	if (err) {
2228 		free(*link_target);
2229 		*link_target = NULL;
2230 	}
2231 	return err;
2232 }
2233 
2234 const struct got_error *
2235 got_object_resolve_symlinks(char **link_target, const char *path,
2236     struct got_object_id *commit_id, struct got_repository *repo)
2237 {
2238 	const struct got_error *err = NULL;
2239 	char *next_target = NULL;
2240 	int max_recursion = 40; /* matches Git */
2241 
2242 	*link_target = NULL;
2243 
2244 	do {
2245 		err = resolve_symlink(&next_target,
2246 		    *link_target ? *link_target : path, commit_id, repo);
2247 		if (err)
2248 			break;
2249 		if (next_target) {
2250 			free(*link_target);
2251 			if (--max_recursion == 0) {
2252 				err = got_error_path(path, GOT_ERR_RECURSION);
2253 				*link_target = NULL;
2254 				break;
2255 			}
2256 			*link_target = next_target;
2257 		}
2258 	} while (next_target);
2259 
2260 	return err;
2261 }
2262 
2263 const struct got_error *
2264 got_traverse_packed_commits(struct got_object_id_queue *traversed_commits,
2265     struct got_object_id *commit_id, const char *path,
2266     struct got_repository *repo)
2267 {
2268 	const struct got_error *err = NULL;
2269 	struct got_pack *pack = NULL;
2270 	struct got_packidx *packidx = NULL;
2271 	char *path_packfile = NULL;
2272 	struct got_commit_object *changed_commit = NULL;
2273 	struct got_object_id *changed_commit_id = NULL;
2274 	int idx;
2275 
2276 	err = got_repo_search_packidx(&packidx, &idx, repo, commit_id);
2277 	if (err) {
2278 		if (err->code != GOT_ERR_NO_OBJ)
2279 			return err;
2280 		return NULL;
2281 	}
2282 
2283 	err = got_packidx_get_packfile_path(&path_packfile,
2284 	    packidx->path_packidx);
2285 	if (err)
2286 		return err;
2287 
2288 	pack = got_repo_get_cached_pack(repo, path_packfile);
2289 	if (pack == NULL) {
2290 		err = got_repo_cache_pack(&pack, repo, path_packfile, packidx);
2291 		if (err)
2292 			goto done;
2293 	}
2294 
2295 	if (pack->privsep_child == NULL) {
2296 		err = start_pack_privsep_child(pack, packidx);
2297 		if (err)
2298 			goto done;
2299 	}
2300 
2301 	err = got_privsep_send_commit_traversal_request(
2302 	    pack->privsep_child->ibuf, commit_id, idx, path);
2303 	if (err)
2304 		goto done;
2305 
2306 	err = got_privsep_recv_traversed_commits(&changed_commit,
2307 	    &changed_commit_id, traversed_commits, pack->privsep_child->ibuf);
2308 	if (err)
2309 		goto done;
2310 
2311 	if (changed_commit) {
2312 		/*
2313 		 * Cache the commit in which the path was changed.
2314 		 * This commit might be opened again soon.
2315 		 */
2316 		changed_commit->refcnt++;
2317 		err = got_repo_cache_commit(repo, changed_commit_id,
2318 		    changed_commit);
2319 		got_object_commit_close(changed_commit);
2320 	}
2321 done:
2322 	free(path_packfile);
2323 	free(changed_commit_id);
2324 	return err;
2325 }