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Date:: Sun Dec 23 22:15:42 2018 UTC
Message:: eliminate got_object_open() round-trip when opening commits
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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 static const struct got_error *
110 recv_imsg_error(struct imsg *imsg, size_t datalen)
111 {
112 	struct got_imsg_error *ierr;
113 
114 	if (datalen != sizeof(*ierr))
115 		return got_error(GOT_ERR_PRIVSEP_LEN);
116 
117 	ierr = imsg->data;
118 	if (ierr->code == GOT_ERR_ERRNO) {
119 		static struct got_error serr;
120 		serr.code = GOT_ERR_ERRNO;
121 		serr.msg = strerror(ierr->errno_code);
122 		return &serr;
123 	}
124 
125 	return got_error(ierr->code);
126 }
127 
128 const struct got_error *
129 got_privsep_recv_imsg(struct imsg *imsg, struct imsgbuf *ibuf,
130     size_t min_datalen)
131 {
132 	const struct got_error *err;
133 	ssize_t n;
134 
135 	n = imsg_get(ibuf, imsg);
136 	if (n == -1)
137 		return got_error_from_errno();
138 
139 	while (n == 0) {
140 		err = read_imsg(ibuf);
141 		if (err)
142 			return err;
143 		n = imsg_get(ibuf, imsg);
144 	}
145 
146 	if (imsg->hdr.len < IMSG_HEADER_SIZE + min_datalen)
147 		return got_error(GOT_ERR_PRIVSEP_LEN);
148 
149 	if (imsg->hdr.type == GOT_IMSG_ERROR) {
150 		size_t datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
151 		return recv_imsg_error(imsg, datalen);
152 	}
153 
154 	return NULL;
155 }
156 
157 /* Attempt to send an error in an imsg. Complain on stderr as a last resort. */
158 void
159 got_privsep_send_error(struct imsgbuf *ibuf, const struct got_error *err)
160 {
161 	const struct got_error *poll_err;
162 	struct got_imsg_error ierr;
163 	int ret;
164 
165 	ierr.code = err->code;
166 	if (err->code == GOT_ERR_ERRNO)
167 		ierr.errno_code = errno;
168 	else
169 		ierr.errno_code = 0;
170 	ret = imsg_compose(ibuf, GOT_IMSG_ERROR, 0, 0, -1, &ierr, sizeof(ierr));
171 	if (ret == -1) {
172 		fprintf(stderr, "%s: error %d \"%s\": imsg_compose: %s\n",
173 		    getprogname(), err->code, err->msg, strerror(errno));
174 		return;
175 	}
176 
177 	poll_err = poll_fd(ibuf->fd, POLLOUT, INFTIM);
178 	if (poll_err) {
179 		fprintf(stderr, "%s: error %d \"%s\": poll: %s\n",
180 		    getprogname(), err->code, err->msg, poll_err->msg);
181 		return;
182 	}
183 
184 	ret = imsg_flush(ibuf);
185 	if (ret == -1) {
186 		fprintf(stderr, "%s: error %d \"%s\": imsg_flush: %s\n",
187 		    getprogname(), err->code, err->msg, strerror(errno));
188 		return;
189 	}
190 }
191 
192 static const struct got_error *
193 flush_imsg(struct imsgbuf *ibuf)
194 {
195 	const struct got_error *err;
196 
197 	err = poll_fd(ibuf->fd, POLLOUT, INFTIM);
198 	if (err)
199 		return err;
200 
201 	if (imsg_flush(ibuf) == -1)
202 		return got_error_from_errno();
203 
204 	return NULL;
205 }
206 
207 const struct got_error *
208 got_privsep_send_stop(int fd)
209 {
210 	const struct got_error *err = NULL;
211 	struct imsgbuf ibuf;
212 
213 	imsg_init(&ibuf, fd);
214 
215 	if (imsg_compose(&ibuf, GOT_IMSG_STOP, 0, 0, -1, NULL, 0) == -1)
216 		return got_error_from_errno();
217 
218 	err = flush_imsg(&ibuf);
219 	imsg_clear(&ibuf);
220 	return err;
221 }
222 
223 const struct got_error *
224 got_privsep_send_obj_req(struct imsgbuf *ibuf, int fd, struct got_object *obj)
225 {
226 	struct got_imsg_object iobj, *iobjp = NULL;
227 	size_t iobj_size = 0;
228 	int imsg_code = GOT_IMSG_OBJECT_REQUEST;
229 
230 	if (obj) {
231 		switch (obj->type) {
232 		case GOT_OBJ_TYPE_TREE:
233 			imsg_code = GOT_IMSG_TREE_REQUEST;
234 			break;
235 		case GOT_OBJ_TYPE_COMMIT:
236 			abort(); /* should not get here */
237 			break;
238 		case GOT_OBJ_TYPE_BLOB:
239 			imsg_code = GOT_IMSG_BLOB_REQUEST;
240 			break;
241 		case GOT_OBJ_TYPE_TAG:
242 			imsg_code = GOT_IMSG_TAG_REQUEST;
243 			break;
244 		default:
245 			return got_error(GOT_ERR_OBJ_TYPE);
246 		}
247 
248 		memcpy(iobj.id, obj->id.sha1, sizeof(iobj.id));
249 		iobj.type = obj->type;
250 		iobj.flags = obj->flags;
251 		iobj.hdrlen = obj->hdrlen;
252 		iobj.size = obj->size;
253 		if (iobj.flags & GOT_OBJ_FLAG_PACKED) {
254 			iobj.pack_offset = obj->pack_offset;
255 			iobj.pack_idx = obj->pack_idx;
256 		}
257 
258 		iobjp = &iobj;
259 		iobj_size = sizeof(iobj);
260 	}
261 
262 	if (imsg_compose(ibuf, imsg_code, 0, 0, fd, iobjp, iobj_size) == -1)
263 		return got_error_from_errno();
264 
265 	return flush_imsg(ibuf);
266 }
267 
268 const struct got_error *
269 got_privsep_send_commit_req(struct imsgbuf *ibuf, int fd,
270     struct got_object_id *id, int pack_idx)
271 {
272 	struct got_imsg_packed_object iobj, *iobjp;
273 	size_t len;
274 
275 	if (id) { /* commit is packed */
276 		iobj.idx = pack_idx;
277 		memcpy(iobj.id, id->sha1, sizeof(iobj.id));
278 		iobjp = &iobj;
279 		len = sizeof(iobj);
280 	} else {
281 		iobjp = NULL;
282 		len = 0;
283 	}
284 
285 	if (imsg_compose(ibuf, GOT_IMSG_COMMIT_REQUEST, 0, 0, fd, iobjp, len)
286 	    == -1)
287 		return got_error_from_errno();
288 
289 	return flush_imsg(ibuf);
290 }
291 
292 const struct got_error *
293 got_privsep_send_blob_req(struct imsgbuf *ibuf, int infd)
294 {
295 	if (imsg_compose(ibuf, GOT_IMSG_BLOB_REQUEST, 0, 0, infd, NULL, 0)
296 	    == -1)
297 		return got_error_from_errno();
298 
299 	return flush_imsg(ibuf);
300 }
301 
302 const struct got_error *
303 got_privsep_send_blob_outfd(struct imsgbuf *ibuf, int outfd)
304 {
305 	if (imsg_compose(ibuf, GOT_IMSG_BLOB_OUTFD, 0, 0, outfd, NULL, 0)
306 	    == -1)
307 		return got_error_from_errno();
308 
309 	return flush_imsg(ibuf);
310 }
311 
312 const struct got_error *
313 got_privsep_send_tmpfd(struct imsgbuf *ibuf, int fd)
314 {
315 	if (imsg_compose(ibuf, GOT_IMSG_TMPFD, 0, 0, fd, NULL, 0)
316 	    == -1)
317 		return got_error_from_errno();
318 
319 	return flush_imsg(ibuf);
320 }
321 
322 const struct got_error *
323 got_privsep_send_obj(struct imsgbuf *ibuf, struct got_object *obj)
324 {
325 	struct got_imsg_object iobj;
326 
327 	memcpy(iobj.id, obj->id.sha1, sizeof(iobj.id));
328 	iobj.type = obj->type;
329 	iobj.flags = obj->flags;
330 	iobj.hdrlen = obj->hdrlen;
331 	iobj.size = obj->size;
332 	if (iobj.flags & GOT_OBJ_FLAG_PACKED) {
333 		iobj.pack_offset = obj->pack_offset;
334 		iobj.pack_idx = obj->pack_idx;
335 	}
336 
337 	if (imsg_compose(ibuf, GOT_IMSG_OBJECT, 0, 0, -1, &iobj, sizeof(iobj))
338 	    == -1)
339 		return got_error_from_errno();
340 
341 	return flush_imsg(ibuf);
342 }
343 
344 const struct got_error *
345 got_privsep_get_imsg_obj(struct got_object **obj, struct imsg *imsg,
346     struct imsgbuf *ibuf)
347 {
348 	const struct got_error *err = NULL;
349 	struct got_imsg_object *iobj;
350 	size_t datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
351 
352 	if (datalen != sizeof(*iobj))
353 		return got_error(GOT_ERR_PRIVSEP_LEN);
354 	iobj = imsg->data;
355 
356 	*obj = calloc(1, sizeof(**obj));
357 	if (*obj == NULL)
358 		return got_error_from_errno();
359 
360 	memcpy((*obj)->id.sha1, iobj->id, SHA1_DIGEST_LENGTH);
361 	(*obj)->type = iobj->type;
362 	(*obj)->flags = iobj->flags;
363 	(*obj)->hdrlen = iobj->hdrlen;
364 	(*obj)->size = iobj->size;
365 	/* path_packfile is handled by caller */
366 	if (iobj->flags & GOT_OBJ_FLAG_PACKED) {
367 		(*obj)->pack_offset = iobj->pack_offset;
368 		(*obj)->pack_idx = iobj->pack_idx;
369 	}
370 
371 	return err;
372 }
373 
374 const struct got_error *
375 got_privsep_recv_obj(struct got_object **obj, struct imsgbuf *ibuf)
376 {
377 	const struct got_error *err = NULL;
378 	struct imsg imsg;
379 	size_t datalen;
380 	const size_t min_datalen =
381 	    MIN(sizeof(struct got_imsg_error), sizeof(struct got_imsg_object));
382 
383 	*obj = NULL;
384 
385 	err = got_privsep_recv_imsg(&imsg, ibuf, min_datalen);
386 	if (err)
387 		return err;
388 
389 	datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
390 
391 	switch (imsg.hdr.type) {
392 	case GOT_IMSG_OBJECT:
393 		err = got_privsep_get_imsg_obj(obj, &imsg, ibuf);
394 		break;
395 	default:
396 		err = got_error(GOT_ERR_PRIVSEP_MSG);
397 		break;
398 	}
399 
400 	imsg_free(&imsg);
401 
402 	return err;
403 }
404 
405 static const struct got_error *
406 send_commit_logmsg(struct imsgbuf *ibuf, struct got_commit_object *commit,
407     size_t logmsg_len)
408 {
409 	const struct got_error *err = NULL;
410 	size_t offset, remain;
411 
412 	offset = 0;
413 	remain = logmsg_len;
414 	while (remain > 0) {
415 		size_t n = MIN(MAX_IMSGSIZE - IMSG_HEADER_SIZE, remain);
416 
417 		if (imsg_compose(ibuf, GOT_IMSG_COMMIT_LOGMSG, 0, 0, -1,
418 		    commit->logmsg + offset, n) == -1) {
419 			err = got_error_from_errno();
420 			break;
421 		}
422 
423 		err = flush_imsg(ibuf);
424 		if (err)
425 			break;
426 
427 		offset += n;
428 		remain -= n;
429 	}
430 
431 	return err;
432 }
433 
434 const struct got_error *
435 got_privsep_send_commit(struct imsgbuf *ibuf, struct got_commit_object *commit)
436 {
437 	const struct got_error *err = NULL;
438 	struct got_imsg_commit_object *icommit;
439 	uint8_t *buf;
440 	size_t len, total;
441 	struct got_object_qid *qid;
442 	size_t author_len = strlen(commit->author);
443 	size_t committer_len = strlen(commit->committer);
444 	size_t logmsg_len = strlen(commit->logmsg);
445 
446 	total = sizeof(*icommit) + author_len + committer_len +
447 	    commit->nparents * SHA1_DIGEST_LENGTH;
448 
449 	buf = malloc(total);
450 	if (buf == NULL)
451 		return got_error_from_errno();
452 
453 	icommit = (struct got_imsg_commit_object *)buf;
454 	memcpy(icommit->tree_id, commit->tree_id->sha1, sizeof(icommit->tree_id));
455 	icommit->author_len = author_len;
456 	icommit->author_time = commit->author_time;
457 	icommit->author_gmtoff = commit->author_gmtoff;
458 	icommit->committer_len = committer_len;
459 	icommit->committer_time = commit->committer_time;
460 	icommit->committer_gmtoff = commit->committer_gmtoff;
461 	icommit->logmsg_len = logmsg_len;
462 	icommit->nparents = commit->nparents;
463 
464 	len = sizeof(*icommit);
465 	memcpy(buf + len, commit->author, author_len);
466 	len += author_len;
467 	memcpy(buf + len, commit->committer, committer_len);
468 	len += committer_len;
469 	SIMPLEQ_FOREACH(qid, &commit->parent_ids, entry) {
470 		memcpy(buf + len, qid->id, SHA1_DIGEST_LENGTH);
471 		len += SHA1_DIGEST_LENGTH;
472 	}
473 
474 	if (imsg_compose(ibuf, GOT_IMSG_COMMIT, 0, 0, -1, buf, len) == -1) {
475 		err = got_error_from_errno();
476 		goto done;
477 	}
478 
479 	if (logmsg_len == 0 ||
480 	    logmsg_len + len > MAX_IMSGSIZE - IMSG_HEADER_SIZE) {
481 		err = flush_imsg(ibuf);
482 		if (err)
483 			goto done;
484 	}
485 	err = send_commit_logmsg(ibuf, commit, logmsg_len);
486 done:
487 	free(buf);
488 	return err;
489 }
490 
491 const struct got_error *
492 got_privsep_recv_commit(struct got_commit_object **commit, struct imsgbuf *ibuf)
493 {
494 	const struct got_error *err = NULL;
495 	struct imsg imsg;
496 	struct got_imsg_commit_object *icommit;
497 	size_t len, datalen;
498 	int i;
499 	const size_t min_datalen =
500 	    MIN(sizeof(struct got_imsg_error),
501 	    sizeof(struct got_imsg_commit_object));
502 
503 	*commit = NULL;
504 
505 	err = got_privsep_recv_imsg(&imsg, ibuf, min_datalen);
506 	if (err)
507 		return err;
508 
509 	datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
510 	len = 0;
511 
512 	switch (imsg.hdr.type) {
513 	case GOT_IMSG_COMMIT:
514 		if (datalen < sizeof(*icommit)) {
515 			err = got_error(GOT_ERR_PRIVSEP_LEN);
516 			break;
517 		}
518 		icommit = imsg.data;
519 		if (datalen != sizeof(*icommit) + icommit->author_len +
520 		    icommit->committer_len +
521 		    icommit->nparents * SHA1_DIGEST_LENGTH) {
522 			err = got_error(GOT_ERR_PRIVSEP_LEN);
523 			break;
524 		}
525 		if (icommit->nparents < 0) {
526 			err = got_error(GOT_ERR_PRIVSEP_LEN);
527 			break;
528 		}
529 		len += sizeof(*icommit);
530 
531 		*commit = got_object_commit_alloc_partial();
532 		if (*commit == NULL) {
533 			err = got_error_from_errno();
534 			break;
535 		}
536 
537 		memcpy((*commit)->tree_id->sha1, icommit->tree_id,
538 		    SHA1_DIGEST_LENGTH);
539 		(*commit)->author_time = icommit->author_time;
540 		(*commit)->author_gmtoff = icommit->author_gmtoff;
541 		(*commit)->committer_time = icommit->committer_time;
542 		(*commit)->committer_gmtoff = icommit->committer_gmtoff;
543 
544 		if (icommit->author_len == 0) {
545 			(*commit)->author = strdup("");
546 			if ((*commit)->author == NULL) {
547 				err = got_error_from_errno();
548 				break;
549 			}
550 		} else {
551 			(*commit)->author = malloc(icommit->author_len + 1);
552 			if ((*commit)->author == NULL) {
553 				err = got_error_from_errno();
554 				break;
555 			}
556 			memcpy((*commit)->author, imsg.data + len,
557 			    icommit->author_len);
558 			(*commit)->author[icommit->author_len] = '\0';
559 		}
560 		len += icommit->author_len;
561 
562 		if (icommit->committer_len == 0) {
563 			(*commit)->committer = strdup("");
564 			if ((*commit)->committer == NULL) {
565 				err = got_error_from_errno();
566 				break;
567 			}
568 		} else {
569 			(*commit)->committer =
570 			    malloc(icommit->committer_len + 1);
571 			if ((*commit)->committer == NULL) {
572 				err = got_error_from_errno();
573 				break;
574 			}
575 			memcpy((*commit)->committer, imsg.data + len,
576 			    icommit->committer_len);
577 			(*commit)->committer[icommit->committer_len] = '\0';
578 		}
579 		len += icommit->committer_len;
580 
581 		if (icommit->logmsg_len == 0) {
582 			(*commit)->logmsg = strdup("");
583 			if ((*commit)->logmsg == NULL) {
584 				err = got_error_from_errno();
585 				break;
586 			}
587 		} else {
588 			size_t offset = 0, remain = icommit->logmsg_len;
589 
590 			(*commit)->logmsg = malloc(icommit->logmsg_len + 1);
591 			if ((*commit)->logmsg == NULL) {
592 				err = got_error_from_errno();
593 				break;
594 			}
595 			while (remain > 0) {
596 				struct imsg imsg_log;
597 				size_t n = MIN(MAX_IMSGSIZE - IMSG_HEADER_SIZE,
598 				    remain);
599 
600 				err = got_privsep_recv_imsg(&imsg_log, ibuf, n);
601 				if (err)
602 					return err;
603 
604 				if (imsg_log.hdr.type != GOT_IMSG_COMMIT_LOGMSG)
605 					return got_error(GOT_ERR_PRIVSEP_MSG);
606 
607 				memcpy((*commit)->logmsg + offset,
608 				    imsg_log.data, n);
609 				imsg_free(&imsg_log);
610 				offset += n;
611 				remain -= n;
612 			}
613 			(*commit)->logmsg[icommit->logmsg_len] = '\0';
614 		}
615 
616 		for (i = 0; i < icommit->nparents; i++) {
617 			struct got_object_qid *qid;
618 
619 			err = got_object_qid_alloc_partial(&qid);
620 			if (err)
621 				break;
622 			memcpy(qid->id, imsg.data + len +
623 			    i * SHA1_DIGEST_LENGTH, sizeof(*qid->id));
624 			SIMPLEQ_INSERT_TAIL(&(*commit)->parent_ids, qid, entry);
625 			(*commit)->nparents++;
626 		}
627 		break;
628 	default:
629 		err = got_error(GOT_ERR_PRIVSEP_MSG);
630 		break;
631 	}
632 
633 	imsg_free(&imsg);
634 
635 	return err;
636 }
637 
638 const struct got_error *
639 got_privsep_send_tree(struct imsgbuf *ibuf, struct got_tree_object *tree)
640 {
641 	const struct got_error *err = NULL;
642 	struct got_imsg_tree_object itree;
643 	struct got_tree_entry *te;
644 	size_t totlen;
645 	int nimsg; /* number of imsg queued in ibuf */
646 
647 	itree.nentries = tree->entries.nentries;
648 	if (imsg_compose(ibuf, GOT_IMSG_TREE, 0, 0, -1, &itree, sizeof(itree))
649 	    == -1)
650 		return got_error_from_errno();
651 
652 	totlen = sizeof(itree);
653 	nimsg = 1;
654 	SIMPLEQ_FOREACH(te, &tree->entries.head, entry) {
655 		struct got_imsg_tree_entry *ite;
656 		uint8_t *buf = NULL;
657 		size_t len = sizeof(*ite) + strlen(te->name);
658 
659 		if (len > MAX_IMSGSIZE)
660 			return got_error(GOT_ERR_NO_SPACE);
661 
662 		nimsg++;
663 		if (totlen + len >= MAX_IMSGSIZE - (IMSG_HEADER_SIZE * nimsg)) {
664 			err = flush_imsg(ibuf);
665 			if (err)
666 				return err;
667 			nimsg = 0;
668 		}
669 
670 		buf = malloc(len);
671 		if (buf == NULL)
672 			return got_error_from_errno();
673 
674 		ite = (struct got_imsg_tree_entry *)buf;
675 		memcpy(ite->id, te->id->sha1, sizeof(ite->id));
676 		ite->mode = te->mode;
677 		memcpy(buf + sizeof(*ite), te->name, strlen(te->name));
678 
679 		if (imsg_compose(ibuf, GOT_IMSG_TREE_ENTRY, 0, 0, -1,
680 		    buf, len) == -1)
681 			err = got_error_from_errno();
682 		free(buf);
683 		if (err)
684 			return err;
685 		totlen += len;
686 	}
687 
688 	return flush_imsg(ibuf);
689 }
690 
691 const struct got_error *
692 got_privsep_recv_tree(struct got_tree_object **tree, struct imsgbuf *ibuf)
693 {
694 	const struct got_error *err = NULL;
695 	const size_t min_datalen =
696 	    MIN(sizeof(struct got_imsg_error),
697 	    sizeof(struct got_imsg_tree_object));
698 	struct got_imsg_tree_object *itree;
699 	int nentries = 0;
700 
701 	*tree = NULL;
702 get_more:
703 	err = read_imsg(ibuf);
704 	if (err)
705 		goto done;
706 
707 	while (1) {
708 		struct imsg imsg;
709 		size_t n;
710 		size_t datalen;
711 		struct got_imsg_tree_entry *ite;
712 		struct got_tree_entry *te = NULL;
713 
714 		n = imsg_get(ibuf, &imsg);
715 		if (n == 0) {
716 			if (*tree && (*tree)->entries.nentries != nentries)
717 				goto get_more;
718 			break;
719 		}
720 
721 		if (imsg.hdr.len < IMSG_HEADER_SIZE + min_datalen)
722 			return got_error(GOT_ERR_PRIVSEP_LEN);
723 
724 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
725 
726 		switch (imsg.hdr.type) {
727 		case GOT_IMSG_ERROR:
728 			err = recv_imsg_error(&imsg, datalen);
729 			break;
730 		case GOT_IMSG_TREE:
731 			/* This message should only appear once. */
732 			if (*tree != NULL) {
733 				err = got_error(GOT_ERR_PRIVSEP_MSG);
734 				break;
735 			}
736 			if (datalen != sizeof(*itree)) {
737 				err = got_error(GOT_ERR_PRIVSEP_LEN);
738 				break;
739 			}
740 			itree = imsg.data;
741 			*tree = malloc(sizeof(**tree));
742 			if (*tree == NULL) {
743 				err = got_error_from_errno();
744 				break;
745 			}
746 			(*tree)->entries.nentries = itree->nentries;
747 			SIMPLEQ_INIT(&(*tree)->entries.head);
748 			(*tree)->refcnt = 0;
749 			break;
750 		case GOT_IMSG_TREE_ENTRY:
751 			/* This message should be preceeded by GOT_IMSG_TREE. */
752 			if (*tree == NULL) {
753 				err = got_error(GOT_ERR_PRIVSEP_MSG);
754 				break;
755 			}
756 			if (datalen < sizeof(*ite) || datalen > MAX_IMSGSIZE) {
757 				err = got_error(GOT_ERR_PRIVSEP_LEN);
758 				break;
759 			}
760 
761 			/* Remaining data contains the entry's name. */
762 			datalen -= sizeof(*ite);
763 			if (datalen == 0 || datalen > MAX_IMSGSIZE) {
764 				err = got_error(GOT_ERR_PRIVSEP_LEN);
765 				break;
766 			}
767 			ite = imsg.data;
768 
769 			te = got_alloc_tree_entry_partial();
770 			if (te == NULL) {
771 				err = got_error_from_errno();
772 				break;
773 			}
774 			te->name = malloc(datalen + 1);
775 			if (te->name == NULL) {
776 				free(te);
777 				err = got_error_from_errno();
778 				break;
779 			}
780 			memcpy(te->name, imsg.data + sizeof(*ite), datalen);
781 			te->name[datalen] = '\0';
782 
783 			memcpy(te->id->sha1, ite->id, SHA1_DIGEST_LENGTH);
784 			te->mode = ite->mode;
785 			SIMPLEQ_INSERT_TAIL(&(*tree)->entries.head, te, entry);
786 			nentries++;
787 			break;
788 		default:
789 			err = got_error(GOT_ERR_PRIVSEP_MSG);
790 			break;
791 		}
792 
793 		imsg_free(&imsg);
794 	}
795 done:
796 	if (*tree && (*tree)->entries.nentries != nentries) {
797 		if (err == NULL)
798 			err = got_error(GOT_ERR_PRIVSEP_LEN);
799 		got_object_tree_close(*tree);
800 		*tree = NULL;
801 	}
802 
803 	return err;
804 }
805 
806 const struct got_error *
807 got_privsep_send_blob(struct imsgbuf *ibuf, size_t size)
808 {
809 	struct got_imsg_blob iblob;
810 
811 	iblob.size = size;
812 	/* Data has already been written to file descriptor. */
813 
814 	if (imsg_compose(ibuf, GOT_IMSG_BLOB, 0, 0, -1, &iblob, sizeof(iblob))
815 	    == -1)
816 		return got_error_from_errno();
817 
818 	return flush_imsg(ibuf);
819 }
820 
821 const struct got_error *
822 got_privsep_recv_blob(size_t *size, struct imsgbuf *ibuf)
823 {
824 	const struct got_error *err = NULL;
825 	struct imsg imsg;
826 	struct got_imsg_blob *iblob;
827 	size_t datalen;
828 
829 	err = got_privsep_recv_imsg(&imsg, ibuf, 0);
830 	if (err)
831 		return err;
832 
833 	datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
834 
835 	switch (imsg.hdr.type) {
836 	case GOT_IMSG_BLOB:
837 		if (datalen != sizeof(*iblob)) {
838 			err = got_error(GOT_ERR_PRIVSEP_LEN);
839 			break;
840 		}
841 		iblob = imsg.data;
842 		*size = iblob->size;
843 		/* Data has been written to file descriptor. */
844 		break;
845 	default:
846 		err = got_error(GOT_ERR_PRIVSEP_MSG);
847 		break;
848 	}
849 
850 	imsg_free(&imsg);
851 
852 	return err;
853 }
854 
855 static const struct got_error *
856 send_tagmsg(struct imsgbuf *ibuf, struct got_tag_object *tag, size_t tagmsg_len)
857 {
858 	const struct got_error *err = NULL;
859 	size_t offset, remain;
860 
861 	offset = 0;
862 	remain = tagmsg_len;
863 	while (remain > 0) {
864 		size_t n = MIN(MAX_IMSGSIZE - IMSG_HEADER_SIZE, remain);
865 
866 		if (imsg_compose(ibuf, GOT_IMSG_TAG_TAGMSG, 0, 0, -1,
867 		    tag->tagmsg + offset, n) == -1) {
868 			err = got_error_from_errno();
869 			break;
870 		}
871 
872 		err = flush_imsg(ibuf);
873 		if (err)
874 			break;
875 
876 		offset += n;
877 		remain -= n;
878 	}
879 
880 	return err;
881 }
882 
883 const struct got_error *
884 got_privsep_send_tag(struct imsgbuf *ibuf, struct got_tag_object *tag)
885 {
886 	const struct got_error *err = NULL;
887 	struct got_imsg_tag_object *itag;
888 	uint8_t *buf;
889 	size_t len, total;
890 	size_t tag_len = strlen(tag->tag);
891 	size_t tagger_len = strlen(tag->tagger);
892 	size_t tagmsg_len = strlen(tag->tagmsg);
893 
894 	total = sizeof(*itag) + tag_len + tagger_len + tagmsg_len;
895 
896 	buf = malloc(total);
897 	if (buf == NULL)
898 		return got_error_from_errno();
899 
900 	itag = (struct got_imsg_tag_object *)buf;
901 	memcpy(itag->id, tag->id.sha1, sizeof(itag->id));
902 	itag->obj_type = tag->obj_type;
903 	itag->tag_len = tag_len;
904 	itag->tagger_len = tagger_len;
905 	itag->tagger_time = tag->tagger_time;
906 	itag->tagger_gmtoff = tag->tagger_gmtoff;
907 	itag->tagmsg_len = tagmsg_len;
908 
909 	len = sizeof(*itag);
910 	memcpy(buf + len, tag->tag, tag_len);
911 	len += tag_len;
912 	memcpy(buf + len, tag->tagger, tagger_len);
913 	len += tagger_len;
914 
915 	if (imsg_compose(ibuf, GOT_IMSG_TAG, 0, 0, -1, buf, len) == -1) {
916 		err = got_error_from_errno();
917 		goto done;
918 	}
919 
920 	if (tagmsg_len == 0 ||
921 	    tagmsg_len + len > MAX_IMSGSIZE - IMSG_HEADER_SIZE) {
922 		err = flush_imsg(ibuf);
923 		if (err)
924 			goto done;
925 	}
926 	err = send_tagmsg(ibuf, tag, tagmsg_len);
927 done:
928 	free(buf);
929 	return err;
930 }
931 
932 const struct got_error *
933 got_privsep_recv_tag(struct got_tag_object **tag, struct imsgbuf *ibuf)
934 {
935 	const struct got_error *err = NULL;
936 	struct imsg imsg;
937 	struct got_imsg_tag_object *itag;
938 	size_t len, datalen;
939 	const size_t min_datalen =
940 	    MIN(sizeof(struct got_imsg_error),
941 	    sizeof(struct got_imsg_tag_object));
942 
943 	*tag = NULL;
944 
945 	err = got_privsep_recv_imsg(&imsg, ibuf, min_datalen);
946 	if (err)
947 		return err;
948 
949 	datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
950 	len = 0;
951 
952 	switch (imsg.hdr.type) {
953 	case GOT_IMSG_TAG:
954 		if (datalen < sizeof(*itag)) {
955 			err = got_error(GOT_ERR_PRIVSEP_LEN);
956 			break;
957 		}
958 		itag = imsg.data;
959 		if (datalen != sizeof(*itag) + itag->tag_len +
960 		    itag->tagger_len) {
961 			err = got_error(GOT_ERR_PRIVSEP_LEN);
962 			break;
963 		}
964 		len += sizeof(*itag);
965 
966 		*tag = calloc(1, sizeof(**tag));
967 		if (*tag == NULL) {
968 			err = got_error_from_errno();
969 			break;
970 		}
971 
972 		memcpy((*tag)->id.sha1, itag->id, SHA1_DIGEST_LENGTH);
973 
974 		if (itag->tag_len == 0) {
975 			(*tag)->tag = strdup("");
976 			if ((*tag)->tag == NULL) {
977 				err = got_error_from_errno();
978 				break;
979 			}
980 		} else {
981 			(*tag)->tag = malloc(itag->tag_len + 1);
982 			if ((*tag)->tag == NULL) {
983 				err = got_error_from_errno();
984 				break;
985 			}
986 			memcpy((*tag)->tag, imsg.data + len,
987 			    itag->tag_len);
988 			(*tag)->tag[itag->tag_len] = '\0';
989 		}
990 		len += itag->tag_len;
991 
992 		(*tag)->obj_type = itag->obj_type;
993 		(*tag)->tagger_time = itag->tagger_time;
994 		(*tag)->tagger_gmtoff = itag->tagger_gmtoff;
995 
996 		if (itag->tagger_len == 0) {
997 			(*tag)->tagger = strdup("");
998 			if ((*tag)->tagger == NULL) {
999 				err = got_error_from_errno();
1000 				break;
1001 			}
1002 		} else {
1003 			(*tag)->tagger = malloc(itag->tagger_len + 1);
1004 			if ((*tag)->tagger == NULL) {
1005 				err = got_error_from_errno();
1006 				break;
1007 			}
1008 			memcpy((*tag)->tagger, imsg.data + len,
1009 			    itag->tagger_len);
1010 			(*tag)->tagger[itag->tagger_len] = '\0';
1011 		}
1012 		len += itag->tagger_len;
1013 
1014 		if (itag->tagmsg_len == 0) {
1015 			(*tag)->tagmsg = strdup("");
1016 			if ((*tag)->tagmsg == NULL) {
1017 				err = got_error_from_errno();
1018 				break;
1019 			}
1020 		} else {
1021 			size_t offset = 0, remain = itag->tagmsg_len;
1022 
1023 			(*tag)->tagmsg = malloc(itag->tagmsg_len + 1);
1024 			if ((*tag)->tagmsg == NULL) {
1025 				err = got_error_from_errno();
1026 				break;
1027 			}
1028 			while (remain > 0) {
1029 				struct imsg imsg_log;
1030 				size_t n = MIN(MAX_IMSGSIZE - IMSG_HEADER_SIZE,
1031 				    remain);
1032 
1033 				err = got_privsep_recv_imsg(&imsg_log, ibuf, n);
1034 				if (err)
1035 					return err;
1036 
1037 				if (imsg_log.hdr.type != GOT_IMSG_TAG_TAGMSG)
1038 					return got_error(GOT_ERR_PRIVSEP_MSG);
1039 
1040 				memcpy((*tag)->tagmsg + offset, imsg_log.data,
1041 				    n);
1042 				imsg_free(&imsg_log);
1043 				offset += n;
1044 				remain -= n;
1045 			}
1046 			(*tag)->tagmsg[itag->tagmsg_len] = '\0';
1047 		}
1048 
1049 		break;
1050 	default:
1051 		err = got_error(GOT_ERR_PRIVSEP_MSG);
1052 		break;
1053 	}
1054 
1055 	imsg_free(&imsg);
1056 
1057 	return err;
1058 }
1059 
1060 const struct got_error *
1061 got_privsep_init_pack_child(struct imsgbuf *ibuf, struct got_pack *pack,
1062     struct got_packidx *packidx)
1063 {
1064 	struct got_imsg_packidx ipackidx;
1065 	struct got_imsg_pack ipack;
1066 	int fd;
1067 
1068 	ipackidx.len = packidx->len;
1069 	fd = dup(packidx->fd);
1070 	if (fd == -1)
1071 		return got_error_from_errno();
1072 
1073 	if (imsg_compose(ibuf, GOT_IMSG_PACKIDX, 0, 0, fd, &ipackidx,
1074 	    sizeof(ipackidx)) == -1)
1075 		return got_error_from_errno();
1076 
1077 	if (strlcpy(ipack.path_packfile, pack->path_packfile,
1078 	    sizeof(ipack.path_packfile)) >= sizeof(ipack.path_packfile))
1079 		return got_error(GOT_ERR_NO_SPACE);
1080 	ipack.filesize = pack->filesize;
1081 
1082 	fd = dup(pack->fd);
1083 	if (fd == -1)
1084 		return got_error_from_errno();
1085 
1086 	if (imsg_compose(ibuf, GOT_IMSG_PACK, 0, 0, fd, &ipack, sizeof(ipack))
1087 	    == -1)
1088 		return got_error_from_errno();
1089 
1090 	return flush_imsg(ibuf);
1091 }
1092 
1093 const struct got_error *
1094 got_privsep_send_packed_obj_req(struct imsgbuf *ibuf, int idx,
1095     struct got_object_id *id)
1096 {
1097 	struct got_imsg_packed_object iobj;
1098 
1099 	iobj.idx = idx;
1100 	memcpy(iobj.id, id->sha1, sizeof(iobj.id));
1101 
1102 	if (imsg_compose(ibuf, GOT_IMSG_PACKED_OBJECT_REQUEST, 0, 0, -1,
1103 	    &iobj, sizeof(iobj)) == -1)
1104 		return got_error_from_errno();
1105 
1106 	return flush_imsg(ibuf);
1107 }