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Date:: Mon Sep 10 10:30:47 2018 UTC
Message:: start reading pack files with privsep; still WIP
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/queue.h>
19 #include <sys/uio.h>
20 #include <sys/syslimits.h>
21 #include <sys/wait.h>
22 
23 #include <stdio.h>
24 #include <stdlib.h>
25 #include <string.h>
26 #include <errno.h>
27 #include <stdint.h>
28 #include <poll.h>
29 #include <imsg.h>
30 #include <sha1.h>
31 #include <zlib.h>
32 #include <time.h>
33 
34 #include "got_object.h"
35 #include "got_error.h"
36 
37 #include "got_lib_sha1.h"
38 #include "got_lib_delta.h"
39 #include "got_lib_inflate.h"
40 #include "got_lib_object.h"
41 #include "got_lib_object_parse.h"
42 #include "got_lib_privsep.h"
43 #include "got_lib_pack.h"
44 
45 #ifndef MIN
46 #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
47 #endif
48 
49 static const struct got_error *
50 poll_fd(int fd, int events, int timeout)
51 {
52 	struct pollfd pfd[1];
53 	int n;
54 
55 	pfd[0].fd = fd;
56 	pfd[0].events = events;
57 
58 	n = poll(pfd, 1, timeout);
59 	if (n == -1)
60 		return got_error_from_errno();
61 	if (n == 0)
62 		return got_error(GOT_ERR_TIMEOUT);
63 	if (pfd[0].revents & (POLLERR | POLLNVAL))
64 		return got_error_from_errno();
65 	if (pfd[0].revents & (events | POLLHUP))
66 		return NULL;
67 
68 	return got_error(GOT_ERR_INTERRUPT);
69 }
70 
71 static const struct got_error *
72 read_imsg(struct imsgbuf *ibuf)
73 {
74 	const struct got_error *err;
75 	size_t n;
76 
77 	err = poll_fd(ibuf->fd, POLLIN, INFTIM);
78 	if (err)
79 		return err;
80 
81 	n = imsg_read(ibuf);
82 	if (n == -1) {
83 		if (errno == EAGAIN) /* Could be a file-descriptor leak. */
84 			return got_error(GOT_ERR_PRIVSEP_NO_FD);
85 		return got_error(GOT_ERR_PRIVSEP_READ);
86 	}
87 	if (n == 0)
88 		return got_error(GOT_ERR_PRIVSEP_PIPE);
89 
90 	return NULL;
91 }
92 
93 const struct got_error *
94 got_privsep_wait_for_child(pid_t pid)
95 {
96 	int child_status;
97 
98 	waitpid(pid, &child_status, 0);
99 
100 	if (!WIFEXITED(child_status))
101 		return got_error(GOT_ERR_PRIVSEP_DIED);
102 
103 	if (WEXITSTATUS(child_status) != 0)
104 		return got_error(GOT_ERR_PRIVSEP_EXIT);
105 
106 	return NULL;
107 }
108 
109 const struct got_error *
110 got_privsep_recv_imsg(struct imsg *imsg, struct imsgbuf *ibuf, size_t min_datalen)
111 {
112 	const struct got_error *err;
113 	ssize_t n;
114 
115 	n = imsg_get(ibuf, imsg);
116 	if (n == -1)
117 		return got_error_from_errno();
118 
119 	while (n == 0) {
120 		err = read_imsg(ibuf);
121 		if (err)
122 			return err;
123 		n = imsg_get(ibuf, imsg);
124 	}
125 
126 	if (imsg->hdr.len < IMSG_HEADER_SIZE + min_datalen)
127 		return got_error(GOT_ERR_PRIVSEP_LEN);
128 
129 	return NULL;
130 }
131 
132 static const struct got_error *
133 recv_imsg_error(struct imsg *imsg, size_t datalen)
134 {
135 	struct got_imsg_error ierr;
136 
137 	if (datalen != sizeof(ierr))
138 		return got_error(GOT_ERR_PRIVSEP_LEN);
139 
140 	memcpy(&ierr, imsg->data, sizeof(ierr));
141 	if (ierr.code == GOT_ERR_ERRNO) {
142 		static struct got_error serr;
143 		serr.code = GOT_ERR_ERRNO;
144 		serr.msg = strerror(ierr.errno_code);
145 		return &serr;
146 	}
147 
148 	return got_error(ierr.code);
149 }
150 
151 /* Attempt to send an error in an imsg. Complain on stderr as a last resort. */
152 void
153 got_privsep_send_error(struct imsgbuf *ibuf, const struct got_error *err)
154 {
155 	const struct got_error *poll_err;
156 	struct got_imsg_error ierr;
157 	int ret;
158 
159 	ierr.code = err->code;
160 	if (err->code == GOT_ERR_ERRNO)
161 		ierr.errno_code = errno;
162 	else
163 		ierr.errno_code = 0;
164 	ret = imsg_compose(ibuf, GOT_IMSG_ERROR, 0, 0, -1, &ierr, sizeof(ierr));
165 	if (ret != -1) {
166 		fprintf(stderr, "%s: error %d \"%s\": imsg_compose: %s\n",
167 		    getprogname(), err->code, err->msg, strerror(errno));
168 		return;
169 	}
170 
171 	poll_err = poll_fd(ibuf->fd, POLLOUT, INFTIM);
172 	if (poll_err) {
173 		fprintf(stderr, "%s: error %d \"%s\": poll: %s\n",
174 		    getprogname(), err->code, err->msg, poll_err->msg);
175 		return;
176 	}
177 
178 	ret = imsg_flush(ibuf);
179 	if (ret == -1) {
180 		fprintf(stderr, "%s: error %d \"%s\": imsg_flush: %s\n",
181 		    getprogname(), err->code, err->msg, strerror(errno));
182 		return;
183 	}
184 }
185 
186 static const struct got_error *
187 flush_imsg(struct imsgbuf *ibuf)
188 {
189 	const struct got_error *err;
190 
191 	err = poll_fd(ibuf->fd, POLLOUT, INFTIM);
192 	if (err)
193 		return err;
194 
195 	if (imsg_flush(ibuf) == -1)
196 		return got_error_from_errno();
197 
198 	return NULL;
199 }
200 
201 const struct got_error *
202 got_privsep_send_stop(int fd)
203 {
204 	const struct got_error *err = NULL;
205 	struct imsgbuf ibuf;
206 
207 	imsg_init(&ibuf, fd);
208 
209 	if (imsg_compose(&ibuf, GOT_IMSG_STOP, 0, 0, -1, NULL, 0) == -1)
210 		return got_error_from_errno();
211 
212 	err = flush_imsg(&ibuf);
213 	imsg_clear(&ibuf);
214 	return err;
215 }
216 
217 const struct got_error *
218 got_privsep_send_obj_req(struct imsgbuf *ibuf, int fd, struct got_object *obj)
219 {
220 	struct got_imsg_object iobj, *iobjp = NULL;
221 	size_t iobj_size = 0;
222 	int imsg_code = GOT_IMSG_OBJECT_REQUEST;
223 
224 	if (obj) {
225 		switch (obj->type) {
226 		case GOT_OBJ_TYPE_TREE:
227 			imsg_code = GOT_IMSG_TREE_REQUEST;
228 			break;
229 		case GOT_OBJ_TYPE_COMMIT:
230 			imsg_code = GOT_IMSG_COMMIT_REQUEST;
231 			break;
232 		default:
233 			return got_error(GOT_ERR_OBJ_TYPE);
234 		}
235 
236 		iobj.type = obj->type;
237 		iobj.flags = obj->flags;
238 		iobj.hdrlen = obj->hdrlen;
239 		iobj.size = obj->size;
240 		iobj.ndeltas = 0;
241 		if (iobj.flags & GOT_OBJ_FLAG_PACKED)
242 			iobj.pack_offset = obj->pack_offset;
243 
244 		iobjp = &iobj;
245 		iobj_size = sizeof(iobj);
246 	}
247 
248 	if (imsg_compose(ibuf, imsg_code, 0, 0, fd, iobjp, iobj_size) == -1)
249 		return got_error_from_errno();
250 
251 	return flush_imsg(ibuf);
252 }
253 
254 const struct got_error *
255 got_privsep_send_blob_req(struct imsgbuf *ibuf, int outfd, int infd)
256 {
257 	const struct got_error *err = NULL;
258 
259 	if (imsg_compose(ibuf, GOT_IMSG_BLOB_REQUEST, 0, 0, infd, NULL, 0)
260 	    == -1) {
261 		close(infd);
262 		close(outfd);
263 		return got_error_from_errno();
264 	}
265 
266 	err = flush_imsg(ibuf);
267 	if (err) {
268 		close(outfd);
269 		return err;
270 	}
271 
272 	if (imsg_compose(ibuf, GOT_IMSG_BLOB_OUTFD, 0, 0, outfd, NULL, 0)
273 	    == -1) {
274 		close(outfd);
275 		return got_error_from_errno();
276 	}
277 
278 	return flush_imsg(ibuf);
279 }
280 
281 static const struct got_error *
282 send_delta(struct got_delta *delta, struct imsgbuf *ibuf)
283 {
284 	struct got_imsg_delta idelta;
285 	size_t offset, remain;
286 
287 	idelta.offset = delta->offset;
288 	idelta.tslen = delta->tslen;
289 	idelta.type = delta->type;
290 	idelta.size = delta->size;
291 	idelta.data_offset = delta->data_offset;
292 	idelta.delta_len = delta->delta_len;
293 
294 	if (imsg_compose(ibuf, GOT_IMSG_DELTA, 0, 0, -1,
295 	    &idelta, sizeof(idelta)) == -1)
296 		return got_error_from_errno();
297 
298 	if (imsg_flush(ibuf) == -1)
299 		return got_error_from_errno();
300 
301 	offset = 0;
302 	remain = delta->delta_len;
303 	while (remain > 0) {
304 		size_t n = MIN(MAX_IMSGSIZE - IMSG_HEADER_SIZE, remain);
305 
306 		if (imsg_compose(ibuf, GOT_IMSG_DELTA_STREAM, 0, 0, -1,
307 		    delta->delta_buf + offset, n) == -1)
308 			return got_error_from_errno();
309 
310 		if (imsg_flush(ibuf) == -1)
311 			return got_error_from_errno();
312 
313 		offset += n;
314 		remain -= n;
315 	}
316 
317 	return NULL;
318 }
319 
320 const struct got_error *
321 got_privsep_send_obj(struct imsgbuf *ibuf, struct got_object *obj)
322 {
323 	const struct got_error *err = NULL;
324 	struct got_imsg_object iobj;
325 	struct got_delta *delta;
326 
327 	iobj.type = obj->type;
328 	iobj.flags = obj->flags;
329 	iobj.hdrlen = obj->hdrlen;
330 	iobj.size = obj->size;
331 	iobj.ndeltas = obj->deltas.nentries;
332 	if (iobj.flags & GOT_OBJ_FLAG_PACKED)
333 		iobj.pack_offset = obj->pack_offset;
334 
335 	if (imsg_compose(ibuf, GOT_IMSG_OBJECT, 0, 0, -1, &iobj, sizeof(iobj))
336 	    == -1)
337 		return got_error_from_errno();
338 
339 	err = flush_imsg(ibuf);
340 	if (err)
341 		return err;
342 
343 	SIMPLEQ_FOREACH(delta, &obj->deltas.entries, entry) {
344 		err = send_delta(delta, ibuf);
345 		if (err)
346 			break;
347 	}
348 
349 	return err;
350 }
351 
352 static const struct got_error *
353 receive_delta(struct got_delta **delta, struct imsgbuf *ibuf)
354 {
355 	const struct got_error *err = NULL;
356 	struct imsg imsg;
357 	struct got_imsg_delta idelta;
358 	uint8_t *delta_buf = NULL;
359 	const size_t min_datalen =
360 	    MIN(sizeof(struct got_imsg_error), sizeof(struct got_imsg_delta));
361 	size_t datalen, offset, remain;
362 
363 	err = got_privsep_recv_imsg(&imsg, ibuf, min_datalen);
364 	if (err)
365 		return err;
366 
367 	datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
368 	if (imsg.hdr.type == GOT_IMSG_ERROR)
369 		return recv_imsg_error(&imsg, datalen);
370 
371 	if (imsg.hdr.type != GOT_IMSG_DELTA)
372 		return got_error(GOT_ERR_PRIVSEP_MSG);
373 	if (datalen != sizeof(idelta))
374 		return got_error(GOT_ERR_PRIVSEP_LEN);
375 
376 	memcpy(&idelta, imsg.data, sizeof(idelta));
377 	imsg_free(&imsg);
378 
379 	switch (idelta.type) {
380 	case GOT_OBJ_TYPE_OFFSET_DELTA:
381 	case GOT_OBJ_TYPE_REF_DELTA:
382 		if (idelta.delta_len < GOT_DELTA_STREAM_LENGTH_MIN)
383 			return got_error(GOT_ERR_BAD_DELTA);
384 		break;
385 	default:
386 		if (idelta.delta_len != 0)
387 			return got_error(GOT_ERR_BAD_DELTA);
388 		break;
389 	}
390 
391 	if (idelta.delta_len > 0) {
392 		delta_buf = calloc(1, idelta.delta_len);
393 		if (delta_buf == NULL)
394 			return got_error_from_errno();
395 
396 		offset = 0;
397 		remain = idelta.delta_len;
398 		while (remain > 0) {
399 			size_t n = MIN(MAX_IMSGSIZE - IMSG_HEADER_SIZE, remain);
400 
401 			err = got_privsep_recv_imsg(&imsg, ibuf, n);
402 			if (err)
403 				return err;
404 
405 			if (imsg.hdr.type == GOT_IMSG_ERROR)
406 				return recv_imsg_error(&imsg, datalen);
407 
408 			if (imsg.hdr.type == GOT_IMSG_STOP)
409 				break;
410 
411 			if (imsg.hdr.type != GOT_IMSG_DELTA_STREAM)
412 				return got_error(GOT_ERR_PRIVSEP_MSG);
413 
414 			datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
415 			if (datalen != n)
416 				return got_error(GOT_ERR_PRIVSEP_LEN);
417 
418 			memcpy(delta_buf + offset, imsg.data, n);
419 			imsg_free(&imsg);
420 
421 			offset += n;
422 			remain -= n;
423 		}
424 	}
425 
426 	*delta = got_delta_open(idelta.offset, idelta.tslen, idelta.type,
427 	    idelta.size, idelta.data_offset, delta_buf, idelta.delta_len);
428 	if (*delta == NULL) {
429 		err = got_error_from_errno();
430 		free(delta_buf);
431 	}
432 
433 	return err;
434 }
435 
436 const struct got_error *
437 got_privsep_recv_obj(struct got_object **obj, struct imsgbuf *ibuf)
438 {
439 	const struct got_error *err = NULL;
440 	struct imsg imsg;
441 	struct got_imsg_object iobj;
442 	size_t datalen;
443 	int i;
444 	const size_t min_datalen =
445 	    MIN(sizeof(struct got_imsg_error), sizeof(struct got_imsg_object));
446 
447 	*obj = NULL;
448 
449 	err = got_privsep_recv_imsg(&imsg, ibuf, min_datalen);
450 	if (err)
451 		return err;
452 
453 	datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
454 
455 	switch (imsg.hdr.type) {
456 	case GOT_IMSG_ERROR:
457 		err = recv_imsg_error(&imsg, datalen);
458 		break;
459 	case GOT_IMSG_OBJECT:
460 		if (datalen != sizeof(iobj)) {
461 			err = got_error(GOT_ERR_PRIVSEP_LEN);
462 			break;
463 		}
464 
465 		memcpy(&iobj, imsg.data, sizeof(iobj));
466 		if (iobj.ndeltas < 0 ||
467 		    iobj.ndeltas > GOT_DELTA_CHAIN_RECURSION_MAX) {
468 			err = got_error(GOT_ERR_PRIVSEP_LEN);
469 			break;
470 		}
471 		if (iobj.ndeltas > 0 &&
472 		    (iobj.flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
473 			err = got_error(GOT_ERR_BAD_OBJ_DATA);
474 			break;
475 		}
476 
477 		*obj = calloc(1, sizeof(**obj));
478 		if (*obj == NULL) {
479 			err = got_error_from_errno();
480 			break;
481 		}
482 
483 		(*obj)->type = iobj.type;
484 		(*obj)->flags = iobj.flags;
485 		(*obj)->hdrlen = iobj.hdrlen;
486 		(*obj)->size = iobj.size;
487 		/* id and path_packfile might be copied in by caller */
488 		(*obj)->pack_offset = iobj.pack_offset;
489 		SIMPLEQ_INIT(&(*obj)->deltas.entries);
490 		for (i = 0; i < iobj.ndeltas; i++) {
491 			struct got_delta *delta;
492 			err = receive_delta(&delta, ibuf);
493 			if (err)
494 				break;
495 			(*obj)->deltas.nentries++;
496 			SIMPLEQ_INSERT_TAIL(&(*obj)->deltas.entries, delta,
497 			    entry);
498 		}
499 		break;
500 	default:
501 		err = got_error(GOT_ERR_PRIVSEP_MSG);
502 		break;
503 	}
504 
505 	imsg_free(&imsg);
506 
507 	return err;
508 }
509 
510 const struct got_error *
511 got_privsep_send_commit(struct imsgbuf *ibuf, struct got_commit_object *commit)
512 {
513 	const struct got_error *err = NULL;
514 	struct got_imsg_commit_object icommit;
515 	uint8_t *buf;
516 	size_t len, total;
517 	struct got_object_qid *qid;
518 
519 	memcpy(icommit.tree_id, commit->tree_id->sha1, sizeof(icommit.tree_id));
520 	icommit.author_len = strlen(commit->author);
521 	memcpy(&icommit.tm_author, &commit->tm_author,
522 	    sizeof(icommit.tm_author));
523 	icommit.committer_len = strlen(commit->committer);
524 	memcpy(&icommit.tm_committer, &commit->tm_committer,
525 	    sizeof(icommit.tm_committer));
526 	icommit.logmsg_len = strlen(commit->logmsg);
527 	icommit.nparents = commit->nparents;
528 
529 	total = sizeof(icommit) + icommit.author_len +
530 	    icommit.committer_len + icommit.logmsg_len +
531 	    icommit.nparents * SHA1_DIGEST_LENGTH;
532 	/* XXX TODO support very large log messages properly */
533 	if (total > MAX_IMSGSIZE)
534 		return got_error(GOT_ERR_NO_SPACE);
535 
536 	buf = malloc(total);
537 	if (buf == NULL)
538 		return got_error_from_errno();
539 
540 	len = 0;
541 	memcpy(buf + len, &icommit, sizeof(icommit));
542 	len += sizeof(icommit);
543 	memcpy(buf + len, commit->author, icommit.author_len);
544 	len += icommit.author_len;
545 	memcpy(buf + len, commit->committer, icommit.committer_len);
546 	len += icommit.committer_len;
547 	memcpy(buf + len, commit->logmsg, icommit.logmsg_len);
548 	len += icommit.logmsg_len;
549 	SIMPLEQ_FOREACH(qid, &commit->parent_ids, entry) {
550 		memcpy(buf + len, qid->id, SHA1_DIGEST_LENGTH);
551 		len += SHA1_DIGEST_LENGTH;
552 	}
553 
554 	if (imsg_compose(ibuf, GOT_IMSG_COMMIT, 0, 0, -1, buf, len) == -1) {
555 		err = got_error_from_errno();
556 		goto done;
557 	}
558 
559 	err = flush_imsg(ibuf);
560 done:
561 	free(buf);
562 	return err;
563 }
564 const struct got_error *
565 got_privsep_recv_commit(struct got_commit_object **commit, struct imsgbuf *ibuf)
566 {
567 	const struct got_error *err = NULL;
568 	struct imsg imsg;
569 	struct got_imsg_commit_object icommit;
570 	size_t len, datalen;
571 	int i;
572 	const size_t min_datalen =
573 	    MIN(sizeof(struct got_imsg_error),
574 	    sizeof(struct got_imsg_commit_object));
575 	uint8_t *data;
576 
577 	*commit = NULL;
578 
579 	err = got_privsep_recv_imsg(&imsg, ibuf, min_datalen);
580 	if (err)
581 		return err;
582 
583 	data = imsg.data;
584 	datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
585 	len = 0;
586 
587 	switch (imsg.hdr.type) {
588 	case GOT_IMSG_ERROR:
589 		err = recv_imsg_error(&imsg, datalen);
590 		break;
591 	case GOT_IMSG_COMMIT:
592 		if (datalen < sizeof(icommit)) {
593 			err = got_error(GOT_ERR_PRIVSEP_LEN);
594 			break;
595 		}
596 
597 		memcpy(&icommit, data, sizeof(icommit));
598 		if (datalen != sizeof(icommit) + icommit.author_len +
599 		    icommit.committer_len + icommit.logmsg_len +
600 		    icommit.nparents * SHA1_DIGEST_LENGTH) {
601 			err = got_error(GOT_ERR_PRIVSEP_LEN);
602 			break;
603 		}
604 		if (icommit.nparents < 0) {
605 			err = got_error(GOT_ERR_PRIVSEP_LEN);
606 			break;
607 		}
608 		len += sizeof(icommit);
609 
610 		*commit = got_object_commit_alloc_partial();
611 		if (*commit == NULL) {
612 			err = got_error_from_errno();
613 			break;
614 		}
615 
616 		memcpy((*commit)->tree_id->sha1, icommit.tree_id,
617 		    SHA1_DIGEST_LENGTH);
618 		memcpy(&(*commit)->tm_author, &icommit.tm_author,
619 		    sizeof((*commit)->tm_author));
620 		memcpy(&(*commit)->tm_committer, &icommit.tm_committer,
621 		    sizeof((*commit)->tm_committer));
622 
623 		if (icommit.author_len == 0) {
624 			(*commit)->author = strdup("");
625 			if ((*commit)->author == NULL) {
626 				err = got_error_from_errno();
627 				break;
628 			}
629 		} else {
630 			(*commit)->author = malloc(icommit.author_len + 1);
631 			if ((*commit)->author == NULL) {
632 				err = got_error_from_errno();
633 				break;
634 			}
635 			memcpy((*commit)->author, data + len,
636 			    icommit.author_len);
637 			(*commit)->author[icommit.author_len] = '\0';
638 		}
639 		len += icommit.author_len;
640 
641 		if (icommit.committer_len == 0) {
642 			(*commit)->committer = strdup("");
643 			if ((*commit)->committer == NULL) {
644 				err = got_error_from_errno();
645 				break;
646 			}
647 		} else {
648 			(*commit)->committer =
649 			    malloc(icommit.committer_len + 1);
650 			if ((*commit)->committer == NULL) {
651 				err = got_error_from_errno();
652 				break;
653 			}
654 			memcpy((*commit)->committer, data + len,
655 			    icommit.committer_len);
656 			(*commit)->committer[icommit.committer_len] = '\0';
657 		}
658 		len += icommit.committer_len;
659 
660 		if (icommit.logmsg_len == 0) {
661 			(*commit)->logmsg = strdup("");
662 			if ((*commit)->logmsg == NULL) {
663 				err = got_error_from_errno();
664 				break;
665 			}
666 		} else {
667 			(*commit)->logmsg = malloc(icommit.logmsg_len + 1);
668 			if ((*commit)->logmsg == NULL) {
669 				err = got_error_from_errno();
670 				break;
671 			}
672 			memcpy((*commit)->logmsg, data + len,
673 			    icommit.logmsg_len);
674 			(*commit)->logmsg[icommit.logmsg_len] = '\0';
675 		}
676 		len += icommit.logmsg_len;
677 
678 		for (i = 0; i < icommit.nparents; i++) {
679 			struct got_object_qid *qid;
680 
681 			qid = calloc(1, sizeof(*qid));
682 			if (qid == NULL) {
683 				err = got_error_from_errno();
684 				break;
685 			}
686 			qid->id = calloc(1, sizeof(*qid->id));
687 			if (qid->id == NULL) {
688 				err = got_error_from_errno();
689 				free(qid);
690 				break;
691 			}
692 
693 			memcpy(qid->id, data + len + i * SHA1_DIGEST_LENGTH,
694 			    sizeof(*qid->id));
695 			SIMPLEQ_INSERT_TAIL(&(*commit)->parent_ids, qid, entry);
696 			(*commit)->nparents++;
697 		}
698 		break;
699 	default:
700 		err = got_error(GOT_ERR_PRIVSEP_MSG);
701 		break;
702 	}
703 
704 	imsg_free(&imsg);
705 
706 	return err;
707 }
708 
709 const struct got_error *
710 got_privsep_send_tree(struct imsgbuf *ibuf, struct got_tree_object *tree)
711 {
712 	const struct got_error *err = NULL;
713 	struct got_imsg_tree_object itree;
714 	struct got_tree_entry *te;
715 
716 	itree.nentries = tree->entries.nentries;
717 	if (imsg_compose(ibuf, GOT_IMSG_TREE, 0, 0, -1, &itree, sizeof(itree))
718 	    == -1)
719 		return got_error_from_errno();
720 
721 	err = flush_imsg(ibuf);
722 	if (err)
723 		return err;
724 
725 	SIMPLEQ_FOREACH(te, &tree->entries.head, entry) {
726 		struct got_imsg_tree_entry ite;
727 		uint8_t *buf = NULL;
728 		size_t len = sizeof(ite) + strlen(te->name);
729 
730 		if (len > MAX_IMSGSIZE)
731 			return got_error(GOT_ERR_NO_SPACE);
732 
733 		buf = malloc(len);
734 		if (buf == NULL)
735 			return got_error_from_errno();
736 
737 		memcpy(ite.id, te->id->sha1, sizeof(ite.id));
738 		ite.mode = te->mode;
739 		memcpy(buf, &ite, sizeof(ite));
740 		memcpy(buf + sizeof(ite), te->name, strlen(te->name));
741 
742 		if (imsg_compose(ibuf, GOT_IMSG_TREE_ENTRY, 0, 0, -1,
743 		    buf, len) == -1)
744 			err = got_error_from_errno();
745 		free(buf);
746 		if (err)
747 			return err;
748 
749 		err = flush_imsg(ibuf);
750 		if (err)
751 			return err;
752 	}
753 
754 	return NULL;
755 }
756 
757 const struct got_error *
758 got_privsep_recv_tree(struct got_tree_object **tree, struct imsgbuf *ibuf)
759 {
760 	const struct got_error *err = NULL;
761 	const size_t min_datalen =
762 	    MIN(sizeof(struct got_imsg_error),
763 	    sizeof(struct got_imsg_tree_object));
764 	struct got_imsg_tree_object itree = { 0 };
765 	int nentries = 0;
766 
767 	*tree = NULL;
768 get_more:
769 	err = read_imsg(ibuf);
770 	if (err)
771 		goto done;
772 
773 	while (1) {
774 		struct imsg imsg;
775 		size_t n;
776 		size_t datalen;
777 		struct got_imsg_tree_entry ite;
778 		struct got_tree_entry *te = NULL;
779 
780 		n = imsg_get(ibuf, &imsg);
781 		if (n == 0) {
782 			if (*tree && (*tree)->entries.nentries != nentries)
783 				goto get_more;
784 			break;
785 		}
786 
787 		if (imsg.hdr.len < IMSG_HEADER_SIZE + min_datalen)
788 			return got_error(GOT_ERR_PRIVSEP_LEN);
789 
790 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
791 
792 		switch (imsg.hdr.type) {
793 		case GOT_IMSG_ERROR:
794 			err = recv_imsg_error(&imsg, datalen);
795 			break;
796 		case GOT_IMSG_TREE:
797 			/* This message should only appear once. */
798 			if (*tree != NULL) {
799 				err = got_error(GOT_ERR_PRIVSEP_MSG);
800 				break;
801 			}
802 			if (datalen != sizeof(itree)) {
803 				err = got_error(GOT_ERR_PRIVSEP_LEN);
804 				break;
805 			}
806 			memcpy(&itree, imsg.data, sizeof(itree));
807 			*tree = calloc(1, sizeof(**tree));
808 			if (*tree == NULL) {
809 				err = got_error_from_errno();
810 				break;
811 			}
812 			(*tree)->entries.nentries = itree.nentries;
813 			SIMPLEQ_INIT(&(*tree)->entries.head);
814 			break;
815 		case GOT_IMSG_TREE_ENTRY:
816 			/* This message should be preceeded by GOT_IMSG_TREE. */
817 			if (*tree == NULL) {
818 				err = got_error(GOT_ERR_PRIVSEP_MSG);
819 				break;
820 			}
821 			if (datalen < sizeof(ite) || datalen > MAX_IMSGSIZE) {
822 				err = got_error(GOT_ERR_PRIVSEP_LEN);
823 				break;
824 			}
825 
826 			/* Remaining data contains the entry's name. */
827 			datalen -= sizeof(ite);
828 			memcpy(&ite, imsg.data, sizeof(ite));
829 			if (datalen == 0 || datalen > MAX_IMSGSIZE) {
830 				err = got_error(GOT_ERR_PRIVSEP_LEN);
831 				break;
832 			}
833 
834 			te = got_alloc_tree_entry_partial();
835 			if (te == NULL) {
836 				err = got_error_from_errno();
837 				break;
838 			}
839 			te->name = malloc(datalen + 1);
840 			if (te->name == NULL) {
841 				free(te);
842 				err = got_error_from_errno();
843 				break;
844 			}
845 			memcpy(te->name, imsg.data + sizeof(ite), datalen);
846 			te->name[datalen] = '\0';
847 
848 			memcpy(te->id->sha1, ite.id, SHA1_DIGEST_LENGTH);
849 			te->mode = ite.mode;
850 			SIMPLEQ_INSERT_TAIL(&(*tree)->entries.head, te, entry);
851 			nentries++;
852 			break;
853 		default:
854 			err = got_error(GOT_ERR_PRIVSEP_MSG);
855 			break;
856 		}
857 
858 		imsg_free(&imsg);
859 	}
860 done:
861 	if (*tree && (*tree)->entries.nentries != nentries) {
862 		if (err == NULL)
863 			err = got_error(GOT_ERR_PRIVSEP_LEN);
864 		got_object_tree_close(*tree);
865 		*tree = NULL;
866 	}
867 
868 	return err;
869 }
870 
871 const struct got_error *
872 got_privsep_send_blob(struct imsgbuf *ibuf, size_t size)
873 {
874 	struct got_imsg_blob iblob;
875 
876 	iblob.size = size;
877 	/* Data has already been written to file descriptor. */
878 
879 	if (imsg_compose(ibuf, GOT_IMSG_BLOB, 0, 0, -1, &iblob, sizeof(iblob))
880 	    == -1)
881 		return got_error_from_errno();
882 
883 	return flush_imsg(ibuf);
884 }
885 
886 const struct got_error *
887 got_privsep_recv_blob(size_t *size, struct imsgbuf *ibuf)
888 {
889 	const struct got_error *err = NULL;
890 	struct imsg imsg;
891 	struct got_imsg_blob iblob;
892 	size_t datalen;
893 
894 	err = got_privsep_recv_imsg(&imsg, ibuf, 0);
895 	if (err)
896 		return err;
897 
898 	datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
899 
900 	switch (imsg.hdr.type) {
901 	case GOT_IMSG_ERROR:
902 		err = recv_imsg_error(&imsg, datalen);
903 		break;
904 	case GOT_IMSG_BLOB:
905 		if (datalen != sizeof(iblob))
906 			err = got_error(GOT_ERR_PRIVSEP_LEN);
907 		memcpy(&iblob, imsg.data, sizeof(iblob));
908 		*size = iblob.size;
909 		/* Data has been written to file descriptor. */
910 		break;
911 	default:
912 		err = got_error(GOT_ERR_PRIVSEP_MSG);
913 		break;
914 	}
915 
916 	imsg_free(&imsg);
917 
918 	return err;
919 }
920 
921 const struct got_error *
922 got_privsep_init_pack_child(struct imsgbuf *ibuf, struct got_pack *pack,
923     struct got_packidx *packidx)
924 {
925 	struct got_imsg_packidx ipackidx;
926 	struct got_imsg_pack ipack;
927 	int fd;
928 
929 	ipackidx.len = packidx->len;
930 	fd = dup(packidx->fd);
931 	if (fd == -1)
932 		return got_error_from_errno();
933 
934 	if (imsg_compose(ibuf, GOT_IMSG_PACKIDX, 0, 0, fd, &ipackidx,
935 	    sizeof(ipackidx)) == -1)
936 		return got_error_from_errno();
937 
938 	if (strlcpy(ipack.path_packfile, pack->path_packfile,
939 	    sizeof(ipack.path_packfile)) >= sizeof(ipack.path_packfile))
940 		return got_error(GOT_ERR_NO_SPACE);
941 	ipack.filesize = pack->filesize;
942 
943 	fd = dup(pack->fd);
944 	if (fd == -1)
945 		return got_error_from_errno();
946 
947 	if (imsg_compose(ibuf, GOT_IMSG_PACK, 0, 0, fd, &ipack, sizeof(ipack))
948 	    == -1)
949 		return got_error_from_errno();
950 
951 	return flush_imsg(ibuf);
952 }
953 
954 const struct got_error *
955 got_privsep_send_packed_obj_req(struct imsgbuf *ibuf, int idx)
956 {
957 	struct got_imsg_packed_object iobj;
958 
959 	iobj.idx = idx;
960 
961 	if (imsg_compose(ibuf, GOT_IMSG_PACKED_OBJECT_REQUEST, 0, 0, -1,
962 	    &iobj, sizeof(iobj)) == -1)
963 		return got_error_from_errno();
964 
965 	return flush_imsg(ibuf);
966 }