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Blob

Date:: Fri Jun 22 08:46:10 2018 UTC
Message:: add a commit cache as well
Actions:: History | Blame | Raw File
1 /*
2  * Copyright (c) 2018 Stefan Sperling <stsp@openbsd.org>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 #include <sys/types.h>
18 #include <sys/stat.h>
19 #include <sys/queue.h>
20 #include <sys/uio.h>
21 #include <sys/socket.h>
22 #include <sys/wait.h>
23 
24 #include <errno.h>
25 #include <fcntl.h>
26 #include <stdio.h>
27 #include <stdlib.h>
28 #include <string.h>
29 #include <stdint.h>
30 #include <sha1.h>
31 #include <zlib.h>
32 #include <ctype.h>
33 #include <limits.h>
34 #include <imsg.h>
35 #include <time.h>
36 
37 #include "got_error.h"
38 #include "got_object.h"
39 #include "got_repository.h"
40 #include "got_opentemp.h"
41 
42 #include "got_lib_sha1.h"
43 #include "got_lib_delta.h"
44 #include "got_lib_pack.h"
45 #include "got_lib_path.h"
46 #include "got_lib_zbuf.h"
47 #include "got_lib_object.h"
48 #include "got_lib_privsep.h"
49 #include "got_lib_repository.h"
50 
51 #ifndef MIN
52 #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
53 #endif
54 
55 #ifndef nitems
56 #define nitems(_a) (sizeof(_a) / sizeof((_a)[0]))
57 #endif
58 
59 #define GOT_OBJ_TAG_COMMIT	"commit"
60 #define GOT_OBJ_TAG_TREE	"tree"
61 #define GOT_OBJ_TAG_BLOB	"blob"
62 
63 #define GOT_COMMIT_TAG_TREE		"tree "
64 #define GOT_COMMIT_TAG_PARENT		"parent "
65 #define GOT_COMMIT_TAG_AUTHOR		"author "
66 #define GOT_COMMIT_TAG_COMMITTER	"committer "
67 
68 const struct got_error *
69 got_object_id_str(char **outbuf, struct got_object_id *id)
70 {
71 	static const size_t len = SHA1_DIGEST_STRING_LENGTH;
72 
73 	*outbuf = calloc(1, len);
74 	if (*outbuf == NULL)
75 		return got_error_from_errno();
76 
77 	if (got_sha1_digest_to_str(id->sha1, *outbuf, len) == NULL) {
78 		free(*outbuf);
79 		*outbuf = NULL;
80 		return got_error(GOT_ERR_BAD_OBJ_ID_STR);
81 	}
82 
83 	return NULL;
84 }
85 
86 int
87 got_object_id_cmp(struct got_object_id *id1, struct got_object_id *id2)
88 {
89 	return memcmp(id1->sha1, id2->sha1, SHA1_DIGEST_LENGTH);
90 }
91 
92 struct got_object_id *
93 got_object_id_dup(struct got_object_id *id1)
94 {
95 	struct got_object_id *id2;
96 
97 	id2 = malloc(sizeof(*id2));
98 	if (id2 == NULL)
99 		return NULL;
100 	memcpy(id2, id1, sizeof(*id2));
101 	return id2;
102 }
103 
104 struct got_object_id *
105 got_object_get_id(struct got_object *obj)
106 {
107 	return got_object_id_dup(&obj->id);
108 }
109 
110 const struct got_error *
111 got_object_get_id_str(char **outbuf, struct got_object *obj)
112 {
113 	return got_object_id_str(outbuf, &obj->id);
114 }
115 
116 int
117 got_object_get_type(struct got_object *obj)
118 {
119 	switch (obj->type) {
120 	case GOT_OBJ_TYPE_COMMIT:
121 	case GOT_OBJ_TYPE_TREE:
122 	case GOT_OBJ_TYPE_BLOB:
123 	case GOT_OBJ_TYPE_TAG:
124 		return obj->type;
125 	default:
126 		abort();
127 		break;
128 	}
129 
130 	/* not reached */
131 	return 0;
132 }
133 
134 static const struct got_error *
135 parse_object_header(struct got_object **obj, char *buf, size_t len)
136 {
137 	const char *obj_tags[] = {
138 		GOT_OBJ_TAG_COMMIT,
139 		GOT_OBJ_TAG_TREE,
140 		GOT_OBJ_TAG_BLOB
141 	};
142 	const int obj_types[] = {
143 		GOT_OBJ_TYPE_COMMIT,
144 		GOT_OBJ_TYPE_TREE,
145 		GOT_OBJ_TYPE_BLOB,
146 	};
147 	int type = 0;
148 	size_t size = 0, hdrlen = 0;
149 	int i;
150 	char *p = strchr(buf, '\0');
151 
152 	if (p == NULL)
153 		return got_error(GOT_ERR_BAD_OBJ_HDR);
154 
155 	hdrlen = strlen(buf) + 1 /* '\0' */;
156 
157 	for (i = 0; i < nitems(obj_tags); i++) {
158 		const char *tag = obj_tags[i];
159 		size_t tlen = strlen(tag);
160 		const char *errstr;
161 
162 		if (strncmp(buf, tag, tlen) != 0)
163 			continue;
164 
165 		type = obj_types[i];
166 		if (len <= tlen)
167 			return got_error(GOT_ERR_BAD_OBJ_HDR);
168 		size = strtonum(buf + tlen, 0, LONG_MAX, &errstr);
169 		if (errstr != NULL)
170 			return got_error(GOT_ERR_BAD_OBJ_HDR);
171 		break;
172 	}
173 
174 	if (type == 0)
175 		return got_error(GOT_ERR_BAD_OBJ_HDR);
176 
177 	*obj = calloc(1, sizeof(**obj));
178 	if (*obj == NULL)
179 		return got_error_from_errno();
180 	(*obj)->type = type;
181 	(*obj)->hdrlen = hdrlen;
182 	(*obj)->size = size;
183 	return NULL;
184 }
185 
186 static const struct got_error *
187 read_object_header(struct got_object **obj, FILE *f)
188 {
189 	const struct got_error *err;
190 	struct got_zstream_buf zb;
191 	char *buf;
192 	const size_t zbsize = 64;
193 	size_t outlen, totlen;
194 	int i;
195 
196 	buf = calloc(zbsize, sizeof(char));
197 	if (buf == NULL)
198 		return got_error_from_errno();
199 
200 	err = got_inflate_init(&zb, NULL, zbsize);
201 	if (err)
202 		return err;
203 
204 	i = 0;
205 	totlen = 0;
206 	do {
207 		err = got_inflate_read(&zb, f, &outlen);
208 		if (err)
209 			goto done;
210 		if (strchr(zb.outbuf, '\0') == NULL) {
211 			buf = recallocarray(buf, 1 + i, 2 + i, zbsize);
212 			if (buf == NULL) {
213 				err = got_error_from_errno();
214 				goto done;
215 			}
216 		}
217 		memcpy(buf + totlen, zb.outbuf, outlen);
218 		totlen += outlen;
219 		i++;
220 	} while (strchr(zb.outbuf, '\0') == NULL);
221 
222 	err = parse_object_header(obj, buf, totlen);
223 done:
224 	got_inflate_end(&zb);
225 	return err;
226 }
227 
228 static void
229 read_object_header_privsep_child(int obj_fd, int imsg_fds[2])
230 {
231 	const struct got_error *err = NULL;
232 	struct got_object *obj = NULL;
233 	struct imsgbuf ibuf;
234 	FILE *f = NULL;
235 	int status = 0;
236 
237 	setproctitle("read object header");
238 	close(imsg_fds[0]);
239 	imsg_init(&ibuf, imsg_fds[1]);
240 
241 	/* revoke access to most system calls */
242 	if (pledge("stdio", NULL) == -1) {
243 		err = got_error_from_errno();
244 		goto done;
245 	}
246 
247 	f = fdopen(obj_fd, "rb");
248 	if (f == NULL) {
249 		err = got_error_from_errno();
250 		close(obj_fd);
251 		goto done;
252 	}
253 
254 	err = read_object_header(&obj, f);
255 	if (err)
256 		goto done;
257 
258 	err = got_privsep_send_obj(&ibuf, obj, 0);
259 done:
260 	if (obj)
261 		got_object_close(obj);
262 	if (err) {
263 		got_privsep_send_error(&ibuf, err);
264 		status = 1;
265 	}
266 	if (f)
267 		fclose(f);
268 	imsg_clear(&ibuf);
269 	close(imsg_fds[1]);
270 	_exit(status);
271 }
272 
273 static const struct got_error *
274 wait_for_child(pid_t pid)
275 {
276 	int child_status;
277 
278 	waitpid(pid, &child_status, 0);
279 
280 	if (!WIFEXITED(child_status))
281 		return got_error(GOT_ERR_PRIVSEP_DIED);
282 
283 	if (WEXITSTATUS(child_status) != 0)
284 		return got_error(GOT_ERR_PRIVSEP_EXIT);
285 
286 	return NULL;
287 }
288 
289 static const struct got_error *
290 read_object_header_privsep(struct got_object **obj, int fd)
291 {
292 	struct imsgbuf parent_ibuf;
293 	int imsg_fds[2];
294 	const struct got_error *err = NULL, *err_child = NULL;
295 	pid_t pid;
296 
297 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1)
298 		return got_error_from_errno();
299 
300 	pid = fork();
301 	if (pid == -1)
302 		return got_error_from_errno();
303 	else if (pid == 0) {
304 		read_object_header_privsep_child(fd, imsg_fds);
305 		/* not reached */
306 	}
307 
308 	close(imsg_fds[1]);
309 	imsg_init(&parent_ibuf, imsg_fds[0]);
310 	err = got_privsep_recv_obj(obj, &parent_ibuf);
311 	imsg_clear(&parent_ibuf);
312 	err_child = wait_for_child(pid);
313 	close(imsg_fds[0]);
314 	return err ? err : err_child;
315 }
316 
317 static const struct got_error *
318 object_path(char **path, struct got_object_id *id, struct got_repository *repo)
319 {
320 	const struct got_error *err = NULL;
321 	char *hex;
322 	char *path_objects = got_repo_get_path_objects(repo);
323 
324 	*path = NULL;
325 
326 	if (path_objects == NULL)
327 		return got_error_from_errno();
328 
329 	err = got_object_id_str(&hex, id);
330 	if (err)
331 		return err;
332 
333 	if (asprintf(path, "%s/%.2x/%s", path_objects,
334 	    id->sha1[0], hex + 2) == -1)
335 		err = got_error_from_errno();
336 
337 	free(hex);
338 	free(path_objects);
339 	return err;
340 }
341 
342 static const struct got_error *
343 open_loose_object(int *fd, struct got_object *obj, struct got_repository *repo)
344 {
345 	const struct got_error *err = NULL;
346 	char *path;
347 
348 	err = object_path(&path, &obj->id, repo);
349 	if (err)
350 		return err;
351 	*fd = open(path, O_RDONLY | O_NOFOLLOW, GOT_DEFAULT_FILE_MODE);
352 	if (*fd == -1) {
353 		err = got_error_from_errno();
354 		goto done;
355 	}
356 done:
357 	free(path);
358 	return err;
359 }
360 
361 const struct got_error *
362 got_object_open(struct got_object **obj, struct got_repository *repo,
363     struct got_object_id *id)
364 {
365 	const struct got_error *err = NULL;
366 	char *path;
367 	int fd;
368 
369 	*obj = got_repo_get_cached_object(repo, id);
370 	if (*obj != NULL) {
371 		(*obj)->refcnt++;
372 		return NULL;
373 	}
374 
375 	err = object_path(&path, id, repo);
376 	if (err)
377 		return err;
378 
379 	fd = open(path, O_RDONLY | O_NOFOLLOW, GOT_DEFAULT_FILE_MODE);
380 	if (fd == -1) {
381 		if (errno != ENOENT) {
382 			err = got_error_from_errno();
383 			goto done;
384 		}
385 		err = got_packfile_open_object(obj, id, repo);
386 		if (err)
387 			goto done;
388 		if (*obj == NULL)
389 			err = got_error(GOT_ERR_NO_OBJ);
390 	} else {
391 		err = read_object_header_privsep(obj, fd);
392 		if (err)
393 			goto done;
394 		memcpy((*obj)->id.sha1, id->sha1, SHA1_DIGEST_LENGTH);
395 	}
396 
397 	if (err == NULL) {
398 		(*obj)->refcnt++;
399 		err = got_repo_cache_object(repo, id, *obj);
400 	}
401 done:
402 	free(path);
403 	if (fd != -1)
404 		close(fd);
405 	return err;
406 
407 }
408 
409 const struct got_error *
410 got_object_open_by_id_str(struct got_object **obj, struct got_repository *repo,
411     const char *id_str)
412 {
413 	struct got_object_id id;
414 
415 	if (!got_parse_sha1_digest(id.sha1, id_str))
416 		return got_error(GOT_ERR_BAD_OBJ_ID_STR);
417 
418 	return got_object_open(obj, repo, &id);
419 }
420 
421 void
422 got_object_close(struct got_object *obj)
423 {
424 	if (obj->refcnt > 0) {
425 		obj->refcnt--;
426 		return;
427 	}
428 
429 	if (obj->flags & GOT_OBJ_FLAG_DELTIFIED) {
430 		struct got_delta *delta;
431 		while (!SIMPLEQ_EMPTY(&obj->deltas.entries)) {
432 			delta = SIMPLEQ_FIRST(&obj->deltas.entries);
433 			SIMPLEQ_REMOVE_HEAD(&obj->deltas.entries, entry);
434 			got_delta_close(delta);
435 		}
436 	}
437 	if (obj->flags & GOT_OBJ_FLAG_PACKED)
438 		free(obj->path_packfile);
439 	free(obj);
440 }
441 
442 struct got_commit_object *
443 got_object_commit_alloc_partial(void)
444 {
445 	struct got_commit_object *commit;
446 
447 	commit = calloc(1, sizeof(*commit));
448 	if (commit == NULL)
449 		return NULL;
450 	commit->tree_id = calloc(1, sizeof(*commit->tree_id));
451 	if (commit->tree_id == NULL) {
452 		free(commit);
453 		return NULL;
454 	}
455 
456 	SIMPLEQ_INIT(&commit->parent_ids);
457 
458 	return commit;
459 }
460 
461 const struct got_error *
462 got_object_open_as_commit(struct got_commit_object **commit,
463     struct got_repository *repo, struct got_object_id *id)
464 {
465 	const struct got_error *err;
466 	struct got_object *obj;
467 
468 	*commit = NULL;
469 
470 	err = got_object_open(&obj, repo, id);
471 	if (err)
472 		return err;
473 	if (got_object_get_type(obj) != GOT_OBJ_TYPE_COMMIT) {
474 		err = got_error(GOT_ERR_OBJ_TYPE);
475 		goto done;
476 	}
477 
478 	err = got_object_commit_open(commit, repo, obj);
479 done:
480 	got_object_close(obj);
481 	return err;
482 }
483 
484 const struct got_error *
485 got_object_commit_add_parent(struct got_commit_object *commit,
486     const char *id_str)
487 {
488 	const struct got_error *err = NULL;
489 	struct got_object_qid *qid;
490 
491 	qid = calloc(1, sizeof(*qid));
492 	if (qid == NULL)
493 		return got_error_from_errno();
494 
495 	qid->id = calloc(1, sizeof(*qid->id));
496 	if (qid->id == NULL) {
497 		err = got_error_from_errno();
498 		free(qid);
499 		return err;
500 	}
501 
502 	if (!got_parse_sha1_digest(qid->id->sha1, id_str)) {
503 		err = got_error(GOT_ERR_BAD_OBJ_DATA);
504 		free(qid->id);
505 		free(qid);
506 		return err;
507 	}
508 
509 	SIMPLEQ_INSERT_TAIL(&commit->parent_ids, qid, entry);
510 	commit->nparents++;
511 
512 	return NULL;
513 }
514 
515 static const struct got_error *
516 parse_gmtoff(time_t *gmtoff, const char *tzstr)
517 {
518 	int sign = 1;
519 	const char *p = tzstr;
520 	time_t h, m;
521 
522 	*gmtoff = 0;
523 
524 	if (*p == '-')
525 		sign = -1;
526 	else if (*p != '+')
527 		return got_error(GOT_ERR_BAD_OBJ_DATA);
528 	p++;
529 	if (!isdigit(*p) && !isdigit(*(p + 1)))
530 		return got_error(GOT_ERR_BAD_OBJ_DATA);
531 	h = (((*p - '0') * 10) + (*(p + 1) - '0'));
532 
533 	p += 2;
534 	if (!isdigit(*p) && !isdigit(*(p + 1)))
535 		return got_error(GOT_ERR_BAD_OBJ_DATA);
536 	m = ((*p - '0') * 10) + (*(p + 1) - '0');
537 
538 	*gmtoff = (h * 60 * 60 + m * 60) * sign;
539 	return NULL;
540 }
541 
542 static const struct got_error *
543 parse_commit_time(struct tm *tm, char *committer)
544 {
545 	const struct got_error *err = NULL;
546 	const char *errstr;
547 	char *space, *tzstr;
548 	time_t gmtoff;
549 	time_t time;
550 
551 	/* Parse and strip off trailing timezone indicator string. */
552 	space = strrchr(committer, ' ');
553 	if (space == NULL)
554 		return got_error(GOT_ERR_BAD_OBJ_DATA);
555 	tzstr = strdup(space + 1);
556 	if (tzstr == NULL)
557 		return got_error_from_errno();
558 	err = parse_gmtoff(&gmtoff, tzstr);
559 	free(tzstr);
560 	if (err)
561 		return err;
562 	*space = '\0';
563 
564 	/* Timestamp is separated from committer name + email by space. */
565 	space = strrchr(committer, ' ');
566 	if (space == NULL)
567 		return got_error(GOT_ERR_BAD_OBJ_DATA);
568 
569 	/* Timestamp parsed here is expressed in comitter's local time. */
570 	time = strtonum(space + 1, 0, INT64_MAX, &errstr);
571 	if (errstr)
572 		return got_error(GOT_ERR_BAD_OBJ_DATA);
573 
574 	/* Express the time stamp in UTC. */
575 	memset(tm, 0, sizeof(*tm));
576 	time -= gmtoff;
577 	if (localtime_r(&time, tm) == NULL)
578 		return got_error_from_errno();
579 	tm->tm_gmtoff = gmtoff;
580 
581 	/* Strip off parsed time information, leaving just author and email. */
582 	*space = '\0';
583 
584 	return NULL;
585 }
586 
587 static const struct got_error *
588 parse_commit_object(struct got_commit_object **commit, char *buf, size_t len)
589 {
590 	const struct got_error *err = NULL;
591 	char *s = buf;
592 	size_t tlen;
593 	ssize_t remain = (ssize_t)len;
594  
595 	*commit = got_object_commit_alloc_partial();
596 	if (*commit == NULL)
597 		return got_error_from_errno();
598 
599 	tlen = strlen(GOT_COMMIT_TAG_TREE);
600 	if (strncmp(s, GOT_COMMIT_TAG_TREE, tlen) == 0) {
601 		remain -= tlen;
602 		if (remain < SHA1_DIGEST_STRING_LENGTH) {
603 			err = got_error(GOT_ERR_BAD_OBJ_DATA);
604 			goto done;
605 		}
606 		s += tlen;
607 		if (!got_parse_sha1_digest((*commit)->tree_id->sha1, s)) {
608 			err = got_error(GOT_ERR_BAD_OBJ_DATA);
609 			goto done;
610 		}
611 		remain -= SHA1_DIGEST_STRING_LENGTH;
612 		s += SHA1_DIGEST_STRING_LENGTH;
613 	} else {
614 		err = got_error(GOT_ERR_BAD_OBJ_DATA);
615 		goto done;
616 	}
617 
618 	tlen = strlen(GOT_COMMIT_TAG_PARENT);
619 	while (strncmp(s, GOT_COMMIT_TAG_PARENT, tlen) == 0) {
620 		remain -= tlen;
621 		if (remain < SHA1_DIGEST_STRING_LENGTH) {
622 			err = got_error(GOT_ERR_BAD_OBJ_DATA);
623 			goto done;
624 		}
625 		s += tlen;
626 		err = got_object_commit_add_parent(*commit, s);
627 		if (err)
628 			goto done;
629 
630 		remain -= SHA1_DIGEST_STRING_LENGTH;
631 		s += SHA1_DIGEST_STRING_LENGTH;
632 	}
633 
634 	tlen = strlen(GOT_COMMIT_TAG_AUTHOR);
635 	if (strncmp(s, GOT_COMMIT_TAG_AUTHOR, tlen) == 0) {
636 		char *p;
637 		size_t slen;
638 
639 		remain -= tlen;
640 		if (remain <= 0) {
641 			err = got_error(GOT_ERR_BAD_OBJ_DATA);
642 			goto done;
643 		}
644 		s += tlen;
645 		p = strchr(s, '\n');
646 		if (p == NULL) {
647 			err = got_error(GOT_ERR_BAD_OBJ_DATA);
648 			goto done;
649 		}
650 		*p = '\0';
651 		slen = strlen(s);
652 		err = parse_commit_time(&(*commit)->tm_author, s);
653 		if (err)
654 			goto done;
655 		(*commit)->author = strdup(s);
656 		if ((*commit)->author == NULL) {
657 			err = got_error_from_errno();
658 			goto done;
659 		}
660 		s += slen + 1;
661 		remain -= slen + 1;
662 	}
663 
664 	tlen = strlen(GOT_COMMIT_TAG_COMMITTER);
665 	if (strncmp(s, GOT_COMMIT_TAG_COMMITTER, tlen) == 0) {
666 		char *p;
667 		size_t slen;
668 
669 		remain -= tlen;
670 		if (remain <= 0) {
671 			err = got_error(GOT_ERR_BAD_OBJ_DATA);
672 			goto done;
673 		}
674 		s += tlen;
675 		p = strchr(s, '\n');
676 		if (p == NULL) {
677 			err = got_error(GOT_ERR_BAD_OBJ_DATA);
678 			goto done;
679 		}
680 		*p = '\0';
681 		slen = strlen(s);
682 		err = parse_commit_time(&(*commit)->tm_committer, s);
683 		if (err)
684 			goto done;
685 		(*commit)->committer = strdup(s);
686 		if ((*commit)->committer == NULL) {
687 			err = got_error_from_errno();
688 			goto done;
689 		}
690 		s += slen + 1;
691 		remain -= slen + 1;
692 	}
693 
694 	(*commit)->logmsg = strndup(s, remain);
695 	if ((*commit)->logmsg == NULL) {
696 		err = got_error_from_errno();
697 		goto done;
698 	}
699 done:
700 	if (err) {
701 		got_object_commit_close(*commit);
702 		*commit = NULL;
703 	}
704 	return err;
705 }
706 
707 static void
708 tree_entry_close(struct got_tree_entry *te)
709 {
710 	free(te->id);
711 	free(te->name);
712 	free(te);
713 }
714 
715 struct got_tree_entry *
716 got_alloc_tree_entry_partial(void)
717 {
718 	struct got_tree_entry *te;
719 
720 	te = calloc(1, sizeof(*te));
721 	if (te == NULL)
722 		return NULL;
723 
724 	te->id = calloc(1, sizeof(*te->id));
725 	if (te->id == NULL) {
726 		free(te);
727 		te = NULL;
728 	}
729 	return te;
730 }
731 
732 static const struct got_error *
733 parse_tree_entry(struct got_tree_entry **te, size_t *elen, char *buf,
734     size_t maxlen)
735 {
736 	char *p = buf, *space;
737 	const struct got_error *err = NULL;
738 
739 	*te = got_alloc_tree_entry_partial();
740 	if (*te == NULL)
741 		return got_error_from_errno();
742 
743 	*elen = strlen(buf) + 1;
744 	if (*elen > maxlen) {
745 		free(*te);
746 		*te = NULL;
747 		return got_error(GOT_ERR_BAD_OBJ_DATA);
748 	}
749 
750 	space = strchr(buf, ' ');
751 	if (space == NULL) {
752 		err = got_error(GOT_ERR_BAD_OBJ_DATA);
753 		free(*te);
754 		*te = NULL;
755 		return err;
756 	}
757 	while (*p != ' ') {
758 		if (*p < '0' && *p > '7') {
759 			err = got_error(GOT_ERR_BAD_OBJ_DATA);
760 			goto done;
761 		}
762 		(*te)->mode <<= 3;
763 		(*te)->mode |= *p - '0';
764 		p++;
765 	}
766 
767 	(*te)->name = strdup(space + 1);
768 	if (*elen > maxlen || maxlen - *elen < SHA1_DIGEST_LENGTH) {
769 		err = got_error(GOT_ERR_BAD_OBJ_DATA);
770 		goto done;
771 	}
772 	buf += strlen(buf) + 1;
773 	memcpy((*te)->id->sha1, buf, SHA1_DIGEST_LENGTH);
774 	*elen += SHA1_DIGEST_LENGTH;
775 done:
776 	if (err) {
777 		tree_entry_close(*te);
778 		*te = NULL;
779 	}
780 	return err;
781 }
782 
783 static const struct got_error *
784 parse_tree_object(struct got_tree_object **tree, uint8_t *buf, size_t len)
785 {
786 	const struct got_error *err;
787 	size_t remain = len;
788 
789 	*tree = calloc(1, sizeof(**tree));
790 	if (*tree == NULL)
791 		return got_error_from_errno();
792 
793 	SIMPLEQ_INIT(&(*tree)->entries);
794 
795 	while (remain > 0) {
796 		struct got_tree_entry *te;
797 		size_t elen;
798 
799 		err = parse_tree_entry(&te, &elen, buf, remain);
800 		if (err)
801 			return err;
802 		(*tree)->nentries++;
803 		SIMPLEQ_INSERT_TAIL(&(*tree)->entries, te, entry);
804 		buf += elen;
805 		remain -= elen;
806 	}
807 
808 	if (remain != 0) {
809 		got_object_tree_close(*tree);
810 		return got_error(GOT_ERR_BAD_OBJ_DATA);
811 	}
812 
813 	return NULL;
814 }
815 
816 static const struct got_error *
817 read_to_mem(uint8_t **outbuf, size_t *outlen, FILE *f)
818 {
819 	const struct got_error *err = NULL;
820 	static const size_t blocksize = 512;
821 	size_t n, total, remain;
822 	uint8_t *buf;
823 
824 	*outbuf = NULL;
825 	*outlen = 0;
826 
827 	buf = calloc(1, blocksize);
828 	if (buf == NULL)
829 		return got_error_from_errno();
830 
831 	remain = blocksize;
832 	total = 0;
833 	while (1) {
834 		if (remain == 0) {
835 			uint8_t *newbuf;
836 			newbuf = reallocarray(buf, 1, total + blocksize);
837 			if (newbuf == NULL) {
838 				err = got_error_from_errno();
839 				goto done;
840 			}
841 			buf = newbuf;
842 			remain += blocksize;
843 		}
844 		n = fread(buf + total, 1, remain, f);
845 		if (n == 0) {
846 			if (ferror(f)) {
847 				err = got_ferror(f, GOT_ERR_IO);
848 				goto done;
849 			}
850 			break; /* EOF */
851 		}
852 		remain -= n;
853 		total += n;
854 	};
855 
856 done:
857 	if (err == NULL) {
858 		*outbuf = buf;
859 		*outlen = total;
860 	} else
861 		free(buf);
862 	return err;
863 }
864 
865 static const struct got_error *
866 read_commit_object(struct got_commit_object **commit, struct got_object *obj,
867     FILE *f)
868 {
869 	const struct got_error *err = NULL;
870 	size_t len;
871 	uint8_t *p;
872 
873 	if (obj->flags & GOT_OBJ_FLAG_PACKED)
874 		err = read_to_mem(&p, &len, f);
875 	else
876 		err = got_inflate_to_mem(&p, &len, f);
877 	if (err)
878 		return err;
879 
880 	if (len < obj->hdrlen + obj->size) {
881 		err = got_error(GOT_ERR_BAD_OBJ_DATA);
882 		goto done;
883 	}
884 
885 	/* Skip object header. */
886 	len -= obj->hdrlen;
887 	err = parse_commit_object(commit, p + obj->hdrlen, len);
888 	free(p);
889 done:
890 	return err;
891 }
892 
893 static void
894 read_commit_object_privsep_child(struct got_object *obj, int obj_fd,
895     int imsg_fds[2])
896 {
897 	const struct got_error *err = NULL;
898 	struct got_commit_object *commit = NULL;
899 	struct imsgbuf ibuf;
900 	FILE *f = NULL;
901 	int status = 0;
902 
903 	setproctitle("read commit object");
904 	close(imsg_fds[0]);
905 	imsg_init(&ibuf, imsg_fds[1]);
906 
907 	/* revoke access to most system calls */
908 	if (pledge("stdio", NULL) == -1) {
909 		err = got_error_from_errno();
910 		goto done;
911 	}
912 
913 	f = fdopen(obj_fd, "rb");
914 	if (f == NULL) {
915 		err = got_error_from_errno();
916 		close(obj_fd);
917 		goto done;
918 	}
919 
920 	err = read_commit_object(&commit, obj, f);
921 	if (err)
922 		goto done;
923 
924 	err = got_privsep_send_commit(&ibuf, commit);
925 done:
926 	if (commit)
927 		got_object_commit_close(commit);
928 	if (err) {
929 		got_privsep_send_error(&ibuf, err);
930 		status = 1;
931 	}
932 	if (f)
933 		fclose(f);
934 	imsg_clear(&ibuf);
935 	close(imsg_fds[1]);
936 	_exit(status);
937 }
938 
939 static const struct got_error *
940 read_commit_object_privsep(struct got_commit_object **commit,
941     struct got_repository *repo, struct got_object *obj, int fd)
942 {
943 	const struct got_error *err = NULL, *err_child = NULL;
944 	struct imsgbuf parent_ibuf;
945 	int imsg_fds[2];
946 	pid_t pid;
947 
948 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1)
949 		return got_error_from_errno();
950 
951 	pid = fork();
952 	if (pid == -1)
953 		return got_error_from_errno();
954 	else if (pid == 0) {
955 		read_commit_object_privsep_child(obj, fd, imsg_fds);
956 		/* not reached */
957 	}
958 
959 	close(imsg_fds[1]);
960 	imsg_init(&parent_ibuf, imsg_fds[0]);
961 	err = got_privsep_recv_commit(commit, &parent_ibuf);
962 	imsg_clear(&parent_ibuf);
963 	err_child = wait_for_child(pid);
964 	close(imsg_fds[0]);
965 	return err ? err : err_child;
966 }
967 
968 const struct got_error *
969 got_object_commit_open(struct got_commit_object **commit,
970     struct got_repository *repo, struct got_object *obj)
971 {
972 	const struct got_error *err = NULL;
973 
974 	*commit = got_repo_get_cached_commit(repo, &obj->id);
975 	if (*commit != NULL) {
976 		(*commit)->refcnt++;
977 		return NULL;
978 	}
979 
980 	if (obj->type != GOT_OBJ_TYPE_COMMIT)
981 		return got_error(GOT_ERR_OBJ_TYPE);
982 
983 	if (obj->flags & GOT_OBJ_FLAG_PACKED) {
984 		uint8_t *buf;
985 		size_t len;
986 		err = got_packfile_extract_object_to_mem(&buf, &len, obj, repo);
987 		if (err)
988 			return err;
989 		obj->size = len;
990 		err = parse_commit_object(commit, buf, len);
991 		free(buf);
992 	} else {
993 		int fd;
994 		err = open_loose_object(&fd, obj, repo);
995 		if (err)
996 			return err;
997 		err = read_commit_object_privsep(commit, repo, obj, fd);
998 		close(fd);
999 	}
1000 
1001 	if (err == NULL) {
1002 		(*commit)->refcnt++;
1003 		err = got_repo_cache_commit(repo, &obj->id, *commit);
1004 	}
1005 
1006 	return err;
1007 }
1008 
1009 void
1010 got_object_commit_close(struct got_commit_object *commit)
1011 {
1012 	struct got_object_qid *qid;
1013 
1014 	if (commit->refcnt > 0) {
1015 		commit->refcnt--;
1016 		return;
1017 	}
1018 
1019 	while (!SIMPLEQ_EMPTY(&commit->parent_ids)) {
1020 		qid = SIMPLEQ_FIRST(&commit->parent_ids);
1021 		SIMPLEQ_REMOVE_HEAD(&commit->parent_ids, entry);
1022 		free(qid->id);
1023 		free(qid);
1024 	}
1025 
1026 	free(commit->tree_id);
1027 	free(commit->author);
1028 	free(commit->committer);
1029 	free(commit->logmsg);
1030 	free(commit);
1031 }
1032 
1033 static const struct got_error *
1034 read_tree_object(struct got_tree_object **tree, struct got_object *obj, FILE *f)
1035 {
1036 	const struct got_error *err = NULL;
1037 	size_t len;
1038 	uint8_t *p;
1039 
1040 	if (obj->flags & GOT_OBJ_FLAG_PACKED)
1041 		err = read_to_mem(&p, &len, f);
1042 	else
1043 		err = got_inflate_to_mem(&p, &len, f);
1044 	if (err)
1045 		return err;
1046 
1047 	if (len < obj->hdrlen + obj->size) {
1048 		err = got_error(GOT_ERR_BAD_OBJ_DATA);
1049 		goto done;
1050 	}
1051 
1052 	/* Skip object header. */
1053 	len -= obj->hdrlen;
1054 	err = parse_tree_object(tree, p + obj->hdrlen, len);
1055 	free(p);
1056 done:
1057 	return err;
1058 }
1059 
1060 static void
1061 read_tree_object_privsep_child(struct got_object *obj, int obj_fd,
1062     int imsg_fds[2])
1063 {
1064 	const struct got_error *err = NULL;
1065 	struct got_tree_object *tree = NULL;
1066 	struct imsgbuf ibuf;
1067 	FILE *f = NULL;
1068 	int status = 0;
1069 
1070 	setproctitle("read tree object");
1071 	close(imsg_fds[0]);
1072 	imsg_init(&ibuf, imsg_fds[1]);
1073 
1074 	/* revoke access to most system calls */
1075 	if (pledge("stdio", NULL) == -1) {
1076 		err = got_error_from_errno();
1077 		goto done;
1078 	}
1079 
1080 	f = fdopen(obj_fd, "rb");
1081 	if (f == NULL) {
1082 		err = got_error_from_errno();
1083 		close(obj_fd);
1084 		goto done;
1085 	}
1086 
1087 	err = read_tree_object(&tree, obj, f);
1088 	if (err)
1089 		goto done;
1090 
1091 	err = got_privsep_send_tree(&ibuf, tree);
1092 done:
1093 	if (tree)
1094 		got_object_tree_close(tree);
1095 	if (err) {
1096 		got_privsep_send_error(&ibuf, err);
1097 		status = 1;
1098 	}
1099 	if (f)
1100 		fclose(f);
1101 	imsg_clear(&ibuf);
1102 	close(imsg_fds[1]);
1103 	_exit(status);
1104 }
1105 
1106 static const struct got_error *
1107 read_tree_object_privsep(struct got_tree_object **tree, struct got_object *obj,
1108     int fd)
1109 {
1110 	const struct got_error *err = NULL, *err_child = NULL;
1111 	struct imsgbuf parent_ibuf;
1112 	int imsg_fds[2];
1113 	pid_t pid;
1114 
1115 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1)
1116 		return got_error_from_errno();
1117 
1118 	pid = fork();
1119 	if (pid == -1)
1120 		return got_error_from_errno();
1121 	else if (pid == 0) {
1122 		read_tree_object_privsep_child(obj, fd, imsg_fds);
1123 		/* not reached */
1124 	}
1125 
1126 	close(imsg_fds[1]);
1127 	imsg_init(&parent_ibuf, imsg_fds[0]);
1128 	err = got_privsep_recv_tree(tree, &parent_ibuf);
1129 	imsg_clear(&parent_ibuf);
1130 	err_child = wait_for_child(pid);
1131 	close(imsg_fds[0]);
1132 	return err ? err : err_child;
1133 }
1134 
1135 const struct got_error *
1136 got_object_tree_open(struct got_tree_object **tree,
1137     struct got_repository *repo, struct got_object *obj)
1138 {
1139 	const struct got_error *err = NULL;
1140 
1141 	*tree = got_repo_get_cached_tree(repo, &obj->id);
1142 	if (*tree != NULL) {
1143 		(*tree)->refcnt++;
1144 		return NULL;
1145 	}
1146 
1147 	if (obj->type != GOT_OBJ_TYPE_TREE)
1148 		return got_error(GOT_ERR_OBJ_TYPE);
1149 
1150 	if (obj->flags & GOT_OBJ_FLAG_PACKED) {
1151 		uint8_t *buf;
1152 		size_t len;
1153 		err = got_packfile_extract_object_to_mem(&buf, &len, obj, repo);
1154 		if (err)
1155 			return err;
1156 		obj->size = len;
1157 		err = parse_tree_object(tree, buf, len);
1158 		free(buf);
1159 	} else {
1160 		int fd;
1161 		err = open_loose_object(&fd, obj, repo);
1162 		if (err)
1163 			return err;
1164 		err = read_tree_object_privsep(tree, obj, fd);
1165 		close(fd);
1166 	}
1167 
1168 	if (err == NULL) {
1169 		(*tree)->refcnt++;
1170 		err = got_repo_cache_tree(repo, &obj->id, *tree);
1171 	}
1172 
1173 	return err;
1174 }
1175 
1176 const struct got_error *
1177 got_object_open_as_tree(struct got_tree_object **tree,
1178     struct got_repository *repo, struct got_object_id *id)
1179 {
1180 	const struct got_error *err;
1181 	struct got_object *obj;
1182 
1183 	*tree = NULL;
1184 
1185 	err = got_object_open(&obj, repo, id);
1186 	if (err)
1187 		return err;
1188 	if (got_object_get_type(obj) != GOT_OBJ_TYPE_TREE) {
1189 		err = got_error(GOT_ERR_OBJ_TYPE);
1190 		goto done;
1191 	}
1192 
1193 	err = got_object_tree_open(tree, repo, obj);
1194 done:
1195 	got_object_close(obj);
1196 	return err;
1197 }
1198 
1199 void
1200 got_object_tree_close(struct got_tree_object *tree)
1201 {
1202 	struct got_tree_entry *te;
1203 
1204 	if (tree->refcnt > 0) {
1205 		tree->refcnt--;
1206 		return;
1207 	}
1208 
1209 	while (!SIMPLEQ_EMPTY(&tree->entries)) {
1210 		te = SIMPLEQ_FIRST(&tree->entries);
1211 		SIMPLEQ_REMOVE_HEAD(&tree->entries, entry);
1212 		tree_entry_close(te);
1213 	}
1214 
1215 	free(tree);
1216 }
1217 
1218 static const struct got_error *
1219 read_blob_object_privsep_child(int outfd, int infd, int imsg_fds[2])
1220 {
1221 	const struct got_error *err = NULL;
1222 	struct imsgbuf ibuf;
1223 	int status = 0;
1224 	size_t size;
1225 	FILE *infile = NULL;
1226 
1227 	setproctitle("read blob object");
1228 	close(imsg_fds[0]);
1229 	imsg_init(&ibuf, imsg_fds[1]);
1230 
1231 	/* revoke access to most system calls */
1232 	if (pledge("stdio", NULL) == -1) {
1233 		err = got_error_from_errno();
1234 		goto done;
1235 	}
1236 
1237 	infile = fdopen(infd, "rb");
1238 	if (infile == NULL) {
1239 		err = got_error_from_errno();
1240 		close(infd);
1241 		goto done;
1242 	}
1243 	err = got_inflate_to_fd(&size, infile, outfd);
1244 	fclose(infile);
1245 	if (err)
1246 		goto done;
1247 
1248 	err = got_privsep_send_blob(&ibuf, size);
1249 done:
1250 	if (err) {
1251 		got_privsep_send_error(&ibuf, err);
1252 		status = 1;
1253 	}
1254 	close(outfd);
1255 	imsg_clear(&ibuf);
1256 	close(imsg_fds[1]);
1257 	_exit(status);
1258 }
1259 
1260 static const struct got_error *
1261 read_blob_object_privsep(size_t *size, int outfd, int infd)
1262 {
1263 	struct imsgbuf parent_ibuf;
1264 	int imsg_fds[2];
1265 	const struct got_error *err = NULL, *err_child = NULL;
1266 	pid_t pid;
1267 
1268 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1)
1269 		return got_error_from_errno();
1270 
1271 	pid = fork();
1272 	if (pid == -1)
1273 		return got_error_from_errno();
1274 	else if (pid == 0) {
1275 		read_blob_object_privsep_child(outfd, infd, imsg_fds);
1276 		/* not reached */
1277 	}
1278 
1279 	close(imsg_fds[1]);
1280 	imsg_init(&parent_ibuf, imsg_fds[0]);
1281 	err = got_privsep_recv_blob(size, &parent_ibuf);
1282 	imsg_clear(&parent_ibuf);
1283 	err_child = wait_for_child(pid);
1284 	close(imsg_fds[0]);
1285 	if (lseek(outfd, SEEK_SET, 0) == -1)
1286 		err = got_error_from_errno();
1287 	return err ? err : err_child;
1288 }
1289 
1290 const struct got_error *
1291 got_object_blob_open(struct got_blob_object **blob,
1292     struct got_repository *repo, struct got_object *obj, size_t blocksize)
1293 {
1294 	const struct got_error *err = NULL;
1295 
1296 	if (obj->type != GOT_OBJ_TYPE_BLOB)
1297 		return got_error(GOT_ERR_OBJ_TYPE);
1298 
1299 	if (blocksize < obj->hdrlen)
1300 		return got_error(GOT_ERR_NO_SPACE);
1301 
1302 	*blob = calloc(1, sizeof(**blob));
1303 	if (*blob == NULL)
1304 		return got_error_from_errno();
1305 
1306 	(*blob)->read_buf = calloc(1, blocksize);
1307 	if ((*blob)->read_buf == NULL) {
1308 		err = got_error_from_errno();
1309 		goto done;
1310 	}
1311 	if (obj->flags & GOT_OBJ_FLAG_PACKED) {
1312 		err = got_packfile_extract_object(&((*blob)->f), obj, repo);
1313 		if (err)
1314 			goto done;
1315 	} else {
1316 		int infd, outfd;
1317 		size_t size;
1318 		struct stat sb;
1319 
1320 		err = open_loose_object(&infd, obj, repo);
1321 		if (err)
1322 			goto done;
1323 
1324 
1325 		outfd = got_opentempfd();
1326 		if (outfd == -1) {
1327 			err = got_error_from_errno();
1328 			close(infd);
1329 			goto done;
1330 		}
1331 
1332 		err = read_blob_object_privsep(&size, outfd, infd);
1333 		close(infd);
1334 		if (err)
1335 			goto done;
1336 
1337 		if (size != obj->hdrlen + obj->size) {
1338 			err = got_error(GOT_ERR_PRIVSEP_LEN);
1339 			close(outfd);
1340 			goto done;
1341 		}
1342 
1343 		if (fstat(outfd, &sb) == -1) {
1344 			err = got_error_from_errno();
1345 			close(outfd);
1346 			goto done;
1347 		}
1348 
1349 		if (sb.st_size != size) {
1350 			err = got_error(GOT_ERR_PRIVSEP_LEN);
1351 			close(outfd);
1352 			goto done;
1353 		}
1354 
1355 		(*blob)->f = fdopen(outfd, "rb");
1356 		if ((*blob)->f == NULL) {
1357 			err = got_error_from_errno();
1358 			close(outfd);
1359 			goto done;
1360 		}
1361 	}
1362 
1363 	(*blob)->hdrlen = obj->hdrlen;
1364 	(*blob)->blocksize = blocksize;
1365 	memcpy(&(*blob)->id.sha1, obj->id.sha1, SHA1_DIGEST_LENGTH);
1366 
1367 done:
1368 	if (err && *blob) {
1369 		if ((*blob)->f)
1370 			fclose((*blob)->f);
1371 		free((*blob)->read_buf);
1372 		free(*blob);
1373 		*blob = NULL;
1374 	}
1375 	return err;
1376 }
1377 
1378 const struct got_error *
1379 got_object_open_as_blob(struct got_blob_object **blob,
1380     struct got_repository *repo, struct got_object_id *id,
1381     size_t blocksize)
1382 {
1383 	const struct got_error *err;
1384 	struct got_object *obj;
1385 
1386 	*blob = NULL;
1387 
1388 	err = got_object_open(&obj, repo, id);
1389 	if (err)
1390 		return err;
1391 	if (got_object_get_type(obj) != GOT_OBJ_TYPE_BLOB) {
1392 		err = got_error(GOT_ERR_OBJ_TYPE);
1393 		goto done;
1394 	}
1395 
1396 	err = got_object_blob_open(blob, repo, obj, blocksize);
1397 done:
1398 	got_object_close(obj);
1399 	return err;
1400 }
1401 
1402 void
1403 got_object_blob_close(struct got_blob_object *blob)
1404 {
1405 	free(blob->read_buf);
1406 	fclose(blob->f);
1407 	free(blob);
1408 }
1409 
1410 char *
1411 got_object_blob_id_str(struct got_blob_object *blob, char *buf, size_t size)
1412 {
1413 	return got_sha1_digest_to_str(blob->id.sha1, buf, size);
1414 }
1415 
1416 size_t
1417 got_object_blob_get_hdrlen(struct got_blob_object *blob)
1418 {
1419 	return blob->hdrlen;
1420 }
1421 
1422 const uint8_t *
1423 got_object_blob_get_read_buf(struct got_blob_object *blob)
1424 {
1425 	return blob->read_buf;
1426 }
1427 
1428 const struct got_error *
1429 got_object_blob_read_block(size_t *outlenp, struct got_blob_object *blob)
1430 {
1431 	size_t n;
1432 
1433 	n = fread(blob->read_buf, 1, blob->blocksize, blob->f);
1434 	if (n == 0 && ferror(blob->f))
1435 		return got_ferror(blob->f, GOT_ERR_IO);
1436 	*outlenp = n;
1437 	return NULL;
1438 }
1439 
1440 const struct got_error *
1441 got_object_blob_dump_to_file(size_t *total_len, FILE *outfile,
1442     struct got_blob_object *blob)
1443 {
1444 	const struct got_error *err = NULL;
1445 	size_t len, hdrlen;
1446 
1447 	*total_len = 0;
1448 	hdrlen = got_object_blob_get_hdrlen(blob);
1449 	do {
1450 		err = got_object_blob_read_block(&len, blob);
1451 		if (err)
1452 			return err;
1453 		if (len == 0)
1454 			break;
1455 		*total_len += len;
1456 		/* Skip blob object header first time around. */
1457 		fwrite(got_object_blob_get_read_buf(blob) + hdrlen,
1458 		    len - hdrlen, 1, outfile);
1459 		hdrlen = 0;
1460 	} while (len != 0);
1461 
1462 	fflush(outfile);
1463 	rewind(outfile);
1464 
1465 	return NULL;
1466 }
1467 
1468 static struct got_tree_entry *
1469 find_entry_by_name(struct got_tree_object *tree, const char *name)
1470 {
1471 	struct got_tree_entry *te;
1472 
1473 	SIMPLEQ_FOREACH(te, &tree->entries, entry) {
1474 		if (strcmp(te->name, name) == 0)
1475 			return te;
1476 	}
1477 	return NULL;
1478 }
1479 
1480 const struct got_error *
1481 got_object_open_by_path(struct got_object **obj, struct got_repository *repo,
1482     struct got_object_id *commit_id, const char *path)
1483 {
1484 	const struct got_error *err = NULL;
1485 	struct got_commit_object *commit = NULL;
1486 	struct got_tree_object *tree = NULL;
1487 	struct got_tree_entry *te = NULL;
1488 	char *seg, *s, *s0 = NULL;
1489 	size_t len = strlen(path);
1490 
1491 	*obj = NULL;
1492 
1493 	/* We are expecting an absolute in-repository path. */
1494 	if (path[0] != '/')
1495 		return got_error(GOT_ERR_NOT_ABSPATH);
1496 
1497 	err = got_object_open_as_commit(&commit, repo, commit_id);
1498 	if (err)
1499 		goto done;
1500 
1501 	/* Handle opening of root of commit's tree. */
1502 	if (path[1] == '\0') {
1503 		err = got_object_open(obj, repo, commit->tree_id);
1504 		if (err)
1505 			goto done;
1506 		return NULL;
1507 	}
1508 
1509 	err = got_object_open_as_tree(&tree, repo, commit->tree_id);
1510 	if (err)
1511 		goto done;
1512 
1513 	s0 = strdup(path);
1514 	if (s0 == NULL) {
1515 		err = got_error_from_errno();
1516 		goto done;
1517 	}
1518 	err = got_canonpath(path, s0, len + 1);
1519 	if (err)
1520 		goto done;
1521 
1522 	s = s0;
1523 	s++; /* skip leading '/' */
1524 	len--;
1525 	seg = s;
1526 	while (len > 0) {
1527 		struct got_tree_object *next_tree;
1528 
1529 		if (*s != '/') {
1530 			s++;
1531 			len--;
1532 			if (*s)
1533 				continue;
1534 		}
1535 
1536 		/* end of path segment */
1537 		*s = '\0';
1538 
1539 		te = find_entry_by_name(tree, seg);
1540 		if (te == NULL) {
1541 			err = got_error(GOT_ERR_NO_OBJ);
1542 			goto done;
1543 		}
1544 
1545 		if (len == 0)
1546 			break;
1547 
1548 		seg = s + 1;
1549 		s++;
1550 		len--;
1551 		if (*s) {
1552 			err = got_object_open_as_tree(&next_tree, repo,
1553 			    te->id);
1554 			te = NULL;
1555 			if (err)
1556 				goto done;
1557 			got_object_tree_close(tree);
1558 			tree = next_tree;
1559 		}
1560 	}
1561 
1562 	if (te) {
1563 		err = got_object_open(obj, repo, te->id);
1564 		if (err)
1565 			goto done;
1566 	} else
1567 		err = got_error(GOT_ERR_NO_OBJ);
1568 done:
1569 	free(s0);
1570 	if (commit)
1571 		got_object_commit_close(commit);
1572 	if (tree)
1573 		got_object_tree_close(tree);
1574 	return err;
1575 }