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Date:: Sat Nov 17 15:04:05 2018 UTC
Message:: more support for tag objects; new code is not yet reachable
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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 			imsg_code = GOT_IMSG_COMMIT_REQUEST;
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_blob_req(struct imsgbuf *ibuf, int infd)
270 {
271 	if (imsg_compose(ibuf, GOT_IMSG_BLOB_REQUEST, 0, 0, infd, NULL, 0)
272 	    == -1)
273 		return got_error_from_errno();
274 
275 	return flush_imsg(ibuf);
276 }
277 
278 const struct got_error *
279 got_privsep_send_blob_outfd(struct imsgbuf *ibuf, int outfd)
280 {
281 	if (imsg_compose(ibuf, GOT_IMSG_BLOB_OUTFD, 0, 0, outfd, NULL, 0)
282 	    == -1)
283 		return got_error_from_errno();
284 
285 	return flush_imsg(ibuf);
286 }
287 
288 const struct got_error *
289 got_privsep_send_tmpfd(struct imsgbuf *ibuf, int fd)
290 {
291 	if (imsg_compose(ibuf, GOT_IMSG_TMPFD, 0, 0, fd, NULL, 0)
292 	    == -1)
293 		return got_error_from_errno();
294 
295 	return flush_imsg(ibuf);
296 }
297 
298 const struct got_error *
299 got_privsep_send_obj(struct imsgbuf *ibuf, struct got_object *obj)
300 {
301 	struct got_imsg_object iobj;
302 
303 	memcpy(iobj.id, obj->id.sha1, sizeof(iobj.id));
304 	iobj.type = obj->type;
305 	iobj.flags = obj->flags;
306 	iobj.hdrlen = obj->hdrlen;
307 	iobj.size = obj->size;
308 	if (iobj.flags & GOT_OBJ_FLAG_PACKED) {
309 		iobj.pack_offset = obj->pack_offset;
310 		iobj.pack_idx = obj->pack_idx;
311 	}
312 
313 	if (imsg_compose(ibuf, GOT_IMSG_OBJECT, 0, 0, -1, &iobj, sizeof(iobj))
314 	    == -1)
315 		return got_error_from_errno();
316 
317 	return flush_imsg(ibuf);
318 }
319 
320 const struct got_error *
321 got_privsep_get_imsg_obj(struct got_object **obj, struct imsg *imsg,
322     struct imsgbuf *ibuf)
323 {
324 	const struct got_error *err = NULL;
325 	struct got_imsg_object *iobj;
326 	size_t datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
327 
328 	if (datalen != sizeof(*iobj))
329 		return got_error(GOT_ERR_PRIVSEP_LEN);
330 	iobj = imsg->data;
331 
332 	*obj = calloc(1, sizeof(**obj));
333 	if (*obj == NULL)
334 		return got_error_from_errno();
335 
336 	memcpy((*obj)->id.sha1, iobj->id, SHA1_DIGEST_LENGTH);
337 	(*obj)->type = iobj->type;
338 	(*obj)->flags = iobj->flags;
339 	(*obj)->hdrlen = iobj->hdrlen;
340 	(*obj)->size = iobj->size;
341 	/* path_packfile is handled by caller */
342 	if (iobj->flags & GOT_OBJ_FLAG_PACKED) {
343 		(*obj)->pack_offset = iobj->pack_offset;
344 		(*obj)->pack_idx = iobj->pack_idx;
345 	}
346 
347 	return err;
348 }
349 
350 const struct got_error *
351 got_privsep_recv_obj(struct got_object **obj, struct imsgbuf *ibuf)
352 {
353 	const struct got_error *err = NULL;
354 	struct imsg imsg;
355 	size_t datalen;
356 	const size_t min_datalen =
357 	    MIN(sizeof(struct got_imsg_error), sizeof(struct got_imsg_object));
358 
359 	*obj = NULL;
360 
361 	err = got_privsep_recv_imsg(&imsg, ibuf, min_datalen);
362 	if (err)
363 		return err;
364 
365 	datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
366 
367 	switch (imsg.hdr.type) {
368 	case GOT_IMSG_OBJECT:
369 		err = got_privsep_get_imsg_obj(obj, &imsg, ibuf);
370 		break;
371 	default:
372 		err = got_error(GOT_ERR_PRIVSEP_MSG);
373 		break;
374 	}
375 
376 	imsg_free(&imsg);
377 
378 	return err;
379 }
380 
381 static const struct got_error *
382 send_commit_logmsg(struct imsgbuf *ibuf, struct got_commit_object *commit,
383     size_t logmsg_len)
384 {
385 	const struct got_error *err = NULL;
386 	size_t offset, remain;
387 
388 	offset = 0;
389 	remain = logmsg_len;
390 	while (remain > 0) {
391 		size_t n = MIN(MAX_IMSGSIZE - IMSG_HEADER_SIZE, remain);
392 
393 		if (imsg_compose(ibuf, GOT_IMSG_COMMIT_LOGMSG, 0, 0, -1,
394 		    commit->logmsg + offset, n) == -1) {
395 			err = got_error_from_errno();
396 			break;
397 		}
398 
399 		err = flush_imsg(ibuf);
400 		if (err)
401 			break;
402 
403 		offset += n;
404 		remain -= n;
405 	}
406 
407 	return err;
408 }
409 
410 const struct got_error *
411 got_privsep_send_commit(struct imsgbuf *ibuf, struct got_commit_object *commit)
412 {
413 	const struct got_error *err = NULL;
414 	struct got_imsg_commit_object *icommit;
415 	uint8_t *buf;
416 	size_t len, total;
417 	struct got_object_qid *qid;
418 	size_t author_len = strlen(commit->author);
419 	size_t committer_len = strlen(commit->committer);
420 	size_t logmsg_len = strlen(commit->logmsg);
421 
422 	total = sizeof(*icommit) + author_len + committer_len +
423 	    commit->nparents * SHA1_DIGEST_LENGTH;
424 
425 	buf = malloc(total);
426 	if (buf == NULL)
427 		return got_error_from_errno();
428 
429 	icommit = (struct got_imsg_commit_object *)buf;
430 	memcpy(icommit->tree_id, commit->tree_id->sha1, sizeof(icommit->tree_id));
431 	icommit->author_len = author_len;
432 	icommit->author_time = commit->author_time;
433 	icommit->author_gmtoff = commit->author_gmtoff;
434 	icommit->committer_len = committer_len;
435 	icommit->committer_time = commit->committer_time;
436 	icommit->committer_gmtoff = commit->committer_gmtoff;
437 	icommit->logmsg_len = logmsg_len;
438 	icommit->nparents = commit->nparents;
439 
440 	len = sizeof(*icommit);
441 	memcpy(buf + len, commit->author, author_len);
442 	len += author_len;
443 	memcpy(buf + len, commit->committer, committer_len);
444 	len += committer_len;
445 	SIMPLEQ_FOREACH(qid, &commit->parent_ids, entry) {
446 		memcpy(buf + len, qid->id, SHA1_DIGEST_LENGTH);
447 		len += SHA1_DIGEST_LENGTH;
448 	}
449 
450 	if (imsg_compose(ibuf, GOT_IMSG_COMMIT, 0, 0, -1, buf, len) == -1) {
451 		err = got_error_from_errno();
452 		goto done;
453 	}
454 
455 	if (logmsg_len == 0 ||
456 	    logmsg_len + len > MAX_IMSGSIZE - IMSG_HEADER_SIZE) {
457 		err = flush_imsg(ibuf);
458 		if (err)
459 			goto done;
460 	}
461 	err = send_commit_logmsg(ibuf, commit, logmsg_len);
462 done:
463 	free(buf);
464 	return err;
465 }
466 
467 const struct got_error *
468 got_privsep_recv_commit(struct got_commit_object **commit, struct imsgbuf *ibuf)
469 {
470 	const struct got_error *err = NULL;
471 	struct imsg imsg;
472 	struct got_imsg_commit_object *icommit;
473 	size_t len, datalen;
474 	int i;
475 	const size_t min_datalen =
476 	    MIN(sizeof(struct got_imsg_error),
477 	    sizeof(struct got_imsg_commit_object));
478 
479 	*commit = NULL;
480 
481 	err = got_privsep_recv_imsg(&imsg, ibuf, min_datalen);
482 	if (err)
483 		return err;
484 
485 	datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
486 	len = 0;
487 
488 	switch (imsg.hdr.type) {
489 	case GOT_IMSG_COMMIT:
490 		if (datalen < sizeof(*icommit)) {
491 			err = got_error(GOT_ERR_PRIVSEP_LEN);
492 			break;
493 		}
494 		icommit = imsg.data;
495 		if (datalen != sizeof(*icommit) + icommit->author_len +
496 		    icommit->committer_len +
497 		    icommit->nparents * SHA1_DIGEST_LENGTH) {
498 			err = got_error(GOT_ERR_PRIVSEP_LEN);
499 			break;
500 		}
501 		if (icommit->nparents < 0) {
502 			err = got_error(GOT_ERR_PRIVSEP_LEN);
503 			break;
504 		}
505 		len += sizeof(*icommit);
506 
507 		*commit = got_object_commit_alloc_partial();
508 		if (*commit == NULL) {
509 			err = got_error_from_errno();
510 			break;
511 		}
512 
513 		memcpy((*commit)->tree_id->sha1, icommit->tree_id,
514 		    SHA1_DIGEST_LENGTH);
515 		(*commit)->author_time = icommit->author_time;
516 		(*commit)->author_gmtoff = icommit->author_gmtoff;
517 		(*commit)->committer_time = icommit->committer_time;
518 		(*commit)->committer_gmtoff = icommit->committer_gmtoff;
519 
520 		if (icommit->author_len == 0) {
521 			(*commit)->author = strdup("");
522 			if ((*commit)->author == NULL) {
523 				err = got_error_from_errno();
524 				break;
525 			}
526 		} else {
527 			(*commit)->author = malloc(icommit->author_len + 1);
528 			if ((*commit)->author == NULL) {
529 				err = got_error_from_errno();
530 				break;
531 			}
532 			memcpy((*commit)->author, imsg.data + len,
533 			    icommit->author_len);
534 			(*commit)->author[icommit->author_len] = '\0';
535 		}
536 		len += icommit->author_len;
537 
538 		if (icommit->committer_len == 0) {
539 			(*commit)->committer = strdup("");
540 			if ((*commit)->committer == NULL) {
541 				err = got_error_from_errno();
542 				break;
543 			}
544 		} else {
545 			(*commit)->committer =
546 			    malloc(icommit->committer_len + 1);
547 			if ((*commit)->committer == NULL) {
548 				err = got_error_from_errno();
549 				break;
550 			}
551 			memcpy((*commit)->committer, imsg.data + len,
552 			    icommit->committer_len);
553 			(*commit)->committer[icommit->committer_len] = '\0';
554 		}
555 		len += icommit->committer_len;
556 
557 		if (icommit->logmsg_len == 0) {
558 			(*commit)->logmsg = strdup("");
559 			if ((*commit)->logmsg == NULL) {
560 				err = got_error_from_errno();
561 				break;
562 			}
563 		} else {
564 			size_t offset = 0, remain = icommit->logmsg_len;
565 
566 			(*commit)->logmsg = malloc(icommit->logmsg_len + 1);
567 			if ((*commit)->logmsg == NULL) {
568 				err = got_error_from_errno();
569 				break;
570 			}
571 			while (remain > 0) {
572 				struct imsg imsg_log;
573 				size_t n = MIN(MAX_IMSGSIZE - IMSG_HEADER_SIZE,
574 				    remain);
575 
576 				err = got_privsep_recv_imsg(&imsg_log, ibuf, n);
577 				if (err)
578 					return err;
579 
580 				if (imsg_log.hdr.type != GOT_IMSG_COMMIT_LOGMSG)
581 					return got_error(GOT_ERR_PRIVSEP_MSG);
582 
583 				memcpy((*commit)->logmsg + offset,
584 				    imsg_log.data, n);
585 				imsg_free(&imsg_log);
586 				offset += n;
587 				remain -= n;
588 			}
589 			(*commit)->logmsg[icommit->logmsg_len] = '\0';
590 		}
591 
592 		for (i = 0; i < icommit->nparents; i++) {
593 			struct got_object_qid *qid;
594 
595 			err = got_object_qid_alloc_partial(&qid);
596 			if (err)
597 				break;
598 			memcpy(qid->id, imsg.data + len +
599 			    i * SHA1_DIGEST_LENGTH, sizeof(*qid->id));
600 			SIMPLEQ_INSERT_TAIL(&(*commit)->parent_ids, qid, entry);
601 			(*commit)->nparents++;
602 		}
603 		break;
604 	default:
605 		err = got_error(GOT_ERR_PRIVSEP_MSG);
606 		break;
607 	}
608 
609 	imsg_free(&imsg);
610 
611 	return err;
612 }
613 
614 const struct got_error *
615 got_privsep_send_tree(struct imsgbuf *ibuf, struct got_tree_object *tree)
616 {
617 	const struct got_error *err = NULL;
618 	struct got_imsg_tree_object itree;
619 	struct got_tree_entry *te;
620 	size_t totlen;
621 	int nimsg; /* number of imsg queued in ibuf */
622 
623 	itree.nentries = tree->entries.nentries;
624 	if (imsg_compose(ibuf, GOT_IMSG_TREE, 0, 0, -1, &itree, sizeof(itree))
625 	    == -1)
626 		return got_error_from_errno();
627 
628 	totlen = sizeof(itree);
629 	nimsg = 1;
630 	SIMPLEQ_FOREACH(te, &tree->entries.head, entry) {
631 		struct got_imsg_tree_entry *ite;
632 		uint8_t *buf = NULL;
633 		size_t len = sizeof(*ite) + strlen(te->name);
634 
635 		if (len > MAX_IMSGSIZE)
636 			return got_error(GOT_ERR_NO_SPACE);
637 
638 		nimsg++;
639 		if (totlen + len >= MAX_IMSGSIZE - (IMSG_HEADER_SIZE * nimsg)) {
640 			err = flush_imsg(ibuf);
641 			if (err)
642 				return err;
643 			nimsg = 0;
644 		}
645 
646 		buf = malloc(len);
647 		if (buf == NULL)
648 			return got_error_from_errno();
649 
650 		ite = (struct got_imsg_tree_entry *)buf;
651 		memcpy(ite->id, te->id->sha1, sizeof(ite->id));
652 		ite->mode = te->mode;
653 		memcpy(buf + sizeof(*ite), te->name, strlen(te->name));
654 
655 		if (imsg_compose(ibuf, GOT_IMSG_TREE_ENTRY, 0, 0, -1,
656 		    buf, len) == -1)
657 			err = got_error_from_errno();
658 		free(buf);
659 		if (err)
660 			return err;
661 		totlen += len;
662 	}
663 
664 	return flush_imsg(ibuf);
665 }
666 
667 const struct got_error *
668 got_privsep_recv_tree(struct got_tree_object **tree, struct imsgbuf *ibuf)
669 {
670 	const struct got_error *err = NULL;
671 	const size_t min_datalen =
672 	    MIN(sizeof(struct got_imsg_error),
673 	    sizeof(struct got_imsg_tree_object));
674 	struct got_imsg_tree_object *itree;
675 	int nentries = 0;
676 
677 	*tree = NULL;
678 get_more:
679 	err = read_imsg(ibuf);
680 	if (err)
681 		goto done;
682 
683 	while (1) {
684 		struct imsg imsg;
685 		size_t n;
686 		size_t datalen;
687 		struct got_imsg_tree_entry *ite;
688 		struct got_tree_entry *te = NULL;
689 
690 		n = imsg_get(ibuf, &imsg);
691 		if (n == 0) {
692 			if (*tree && (*tree)->entries.nentries != nentries)
693 				goto get_more;
694 			break;
695 		}
696 
697 		if (imsg.hdr.len < IMSG_HEADER_SIZE + min_datalen)
698 			return got_error(GOT_ERR_PRIVSEP_LEN);
699 
700 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
701 
702 		switch (imsg.hdr.type) {
703 		case GOT_IMSG_ERROR:
704 			err = recv_imsg_error(&imsg, datalen);
705 			break;
706 		case GOT_IMSG_TREE:
707 			/* This message should only appear once. */
708 			if (*tree != NULL) {
709 				err = got_error(GOT_ERR_PRIVSEP_MSG);
710 				break;
711 			}
712 			if (datalen != sizeof(*itree)) {
713 				err = got_error(GOT_ERR_PRIVSEP_LEN);
714 				break;
715 			}
716 			itree = imsg.data;
717 			*tree = malloc(sizeof(**tree));
718 			if (*tree == NULL) {
719 				err = got_error_from_errno();
720 				break;
721 			}
722 			(*tree)->entries.nentries = itree->nentries;
723 			SIMPLEQ_INIT(&(*tree)->entries.head);
724 			(*tree)->refcnt = 0;
725 			break;
726 		case GOT_IMSG_TREE_ENTRY:
727 			/* This message should be preceeded by GOT_IMSG_TREE. */
728 			if (*tree == NULL) {
729 				err = got_error(GOT_ERR_PRIVSEP_MSG);
730 				break;
731 			}
732 			if (datalen < sizeof(*ite) || datalen > MAX_IMSGSIZE) {
733 				err = got_error(GOT_ERR_PRIVSEP_LEN);
734 				break;
735 			}
736 
737 			/* Remaining data contains the entry's name. */
738 			datalen -= sizeof(*ite);
739 			if (datalen == 0 || datalen > MAX_IMSGSIZE) {
740 				err = got_error(GOT_ERR_PRIVSEP_LEN);
741 				break;
742 			}
743 			ite = imsg.data;
744 
745 			te = got_alloc_tree_entry_partial();
746 			if (te == NULL) {
747 				err = got_error_from_errno();
748 				break;
749 			}
750 			te->name = malloc(datalen + 1);
751 			if (te->name == NULL) {
752 				free(te);
753 				err = got_error_from_errno();
754 				break;
755 			}
756 			memcpy(te->name, imsg.data + sizeof(*ite), datalen);
757 			te->name[datalen] = '\0';
758 
759 			memcpy(te->id->sha1, ite->id, SHA1_DIGEST_LENGTH);
760 			te->mode = ite->mode;
761 			SIMPLEQ_INSERT_TAIL(&(*tree)->entries.head, te, entry);
762 			nentries++;
763 			break;
764 		default:
765 			err = got_error(GOT_ERR_PRIVSEP_MSG);
766 			break;
767 		}
768 
769 		imsg_free(&imsg);
770 	}
771 done:
772 	if (*tree && (*tree)->entries.nentries != nentries) {
773 		if (err == NULL)
774 			err = got_error(GOT_ERR_PRIVSEP_LEN);
775 		got_object_tree_close(*tree);
776 		*tree = NULL;
777 	}
778 
779 	return err;
780 }
781 
782 const struct got_error *
783 got_privsep_send_blob(struct imsgbuf *ibuf, size_t size)
784 {
785 	struct got_imsg_blob iblob;
786 
787 	iblob.size = size;
788 	/* Data has already been written to file descriptor. */
789 
790 	if (imsg_compose(ibuf, GOT_IMSG_BLOB, 0, 0, -1, &iblob, sizeof(iblob))
791 	    == -1)
792 		return got_error_from_errno();
793 
794 	return flush_imsg(ibuf);
795 }
796 
797 const struct got_error *
798 got_privsep_recv_blob(size_t *size, struct imsgbuf *ibuf)
799 {
800 	const struct got_error *err = NULL;
801 	struct imsg imsg;
802 	struct got_imsg_blob *iblob;
803 	size_t datalen;
804 
805 	err = got_privsep_recv_imsg(&imsg, ibuf, 0);
806 	if (err)
807 		return err;
808 
809 	datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
810 
811 	switch (imsg.hdr.type) {
812 	case GOT_IMSG_BLOB:
813 		if (datalen != sizeof(*iblob)) {
814 			err = got_error(GOT_ERR_PRIVSEP_LEN);
815 			break;
816 		}
817 		iblob = imsg.data;
818 		*size = iblob->size;
819 		/* Data has been written to file descriptor. */
820 		break;
821 	default:
822 		err = got_error(GOT_ERR_PRIVSEP_MSG);
823 		break;
824 	}
825 
826 	imsg_free(&imsg);
827 
828 	return err;
829 }
830 
831 static const struct got_error *
832 send_tagmsg(struct imsgbuf *ibuf, struct got_tag_object *tag, size_t tagmsg_len)
833 {
834 	const struct got_error *err = NULL;
835 	size_t offset, remain;
836 
837 	offset = 0;
838 	remain = tagmsg_len;
839 	while (remain > 0) {
840 		size_t n = MIN(MAX_IMSGSIZE - IMSG_HEADER_SIZE, remain);
841 
842 		if (imsg_compose(ibuf, GOT_IMSG_TAG_TAGMSG, 0, 0, -1,
843 		    tag->tagmsg + offset, n) == -1) {
844 			err = got_error_from_errno();
845 			break;
846 		}
847 
848 		err = flush_imsg(ibuf);
849 		if (err)
850 			break;
851 
852 		offset += n;
853 		remain -= n;
854 	}
855 
856 	return err;
857 }
858 
859 const struct got_error *
860 got_privsep_send_tag(struct imsgbuf *ibuf, struct got_tag_object *tag)
861 {
862 	const struct got_error *err = NULL;
863 	struct got_imsg_tag_object *itag;
864 	uint8_t *buf;
865 	size_t len, total;
866 	size_t tag_len = strlen(tag->tag);
867 	size_t tagger_len = strlen(tag->tagger);
868 	size_t tagmsg_len = strlen(tag->tagmsg);
869 
870 	total = sizeof(*itag) + tag_len + tagger_len + tagmsg_len;
871 
872 	buf = malloc(total);
873 	if (buf == NULL)
874 		return got_error_from_errno();
875 
876 	itag = (struct got_imsg_tag_object *)buf;
877 	memcpy(itag->id, tag->id.sha1, sizeof(itag->id));
878 	itag->obj_type = tag->obj_type;
879 	itag->tag_len = tag_len;
880 	itag->tagger_len = tagger_len;
881 	itag->tagger_time = tag->tagger_time;
882 	itag->tagger_gmtoff = tag->tagger_gmtoff;
883 	itag->tagmsg_len = tagmsg_len;
884 
885 	len = sizeof(*itag);
886 	memcpy(buf + len, tag->tag, tag_len);
887 	len += tag_len;
888 	memcpy(buf + len, tag->tagger, tagger_len);
889 	len += tagger_len;
890 
891 	if (imsg_compose(ibuf, GOT_IMSG_TAG, 0, 0, -1, buf, len) == -1) {
892 		err = got_error_from_errno();
893 		goto done;
894 	}
895 
896 	if (tagmsg_len == 0 ||
897 	    tagmsg_len + len > MAX_IMSGSIZE - IMSG_HEADER_SIZE) {
898 		err = flush_imsg(ibuf);
899 		if (err)
900 			goto done;
901 	}
902 	err = send_tagmsg(ibuf, tag, tagmsg_len);
903 done:
904 	free(buf);
905 	return err;
906 }
907 
908 const struct got_error *
909 got_privsep_recv_tag(struct got_tag_object **tag, struct imsgbuf *ibuf)
910 {
911 	const struct got_error *err = NULL;
912 	struct imsg imsg;
913 	struct got_imsg_tag_object *itag;
914 	size_t len, datalen;
915 	const size_t min_datalen =
916 	    MIN(sizeof(struct got_imsg_error),
917 	    sizeof(struct got_imsg_tag_object));
918 
919 	*tag = NULL;
920 
921 	err = got_privsep_recv_imsg(&imsg, ibuf, min_datalen);
922 	if (err)
923 		return err;
924 
925 	datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
926 	len = 0;
927 
928 	switch (imsg.hdr.type) {
929 	case GOT_IMSG_TAG:
930 		if (datalen < sizeof(*itag)) {
931 			err = got_error(GOT_ERR_PRIVSEP_LEN);
932 			break;
933 		}
934 		itag = imsg.data;
935 		if (datalen != sizeof(*itag) + itag->tag_len +
936 		    itag->tagger_len) {
937 			err = got_error(GOT_ERR_PRIVSEP_LEN);
938 			break;
939 		}
940 		len += sizeof(*itag);
941 
942 		*tag = calloc(1, sizeof(**tag));
943 		if (*tag == NULL) {
944 			err = got_error_from_errno();
945 			break;
946 		}
947 
948 		memcpy((*tag)->id.sha1, itag->id, SHA1_DIGEST_LENGTH);
949 
950 		if (itag->tag_len == 0) {
951 			(*tag)->tag = strdup("");
952 			if ((*tag)->tag == NULL) {
953 				err = got_error_from_errno();
954 				break;
955 			}
956 		} else {
957 			(*tag)->tag = malloc(itag->tag_len + 1);
958 			if ((*tag)->tag == NULL) {
959 				err = got_error_from_errno();
960 				break;
961 			}
962 			memcpy((*tag)->tag, imsg.data + len,
963 			    itag->tag_len);
964 			(*tag)->tag[itag->tag_len] = '\0';
965 		}
966 		len += itag->tag_len;
967 
968 		(*tag)->obj_type = itag->obj_type;
969 		(*tag)->tagger_time = itag->tagger_time;
970 		(*tag)->tagger_gmtoff = itag->tagger_gmtoff;
971 
972 		if (itag->tagger_len == 0) {
973 			(*tag)->tagger = strdup("");
974 			if ((*tag)->tagger == NULL) {
975 				err = got_error_from_errno();
976 				break;
977 			}
978 		} else {
979 			(*tag)->tagger = malloc(itag->tagger_len + 1);
980 			if ((*tag)->tagger == NULL) {
981 				err = got_error_from_errno();
982 				break;
983 			}
984 			memcpy((*tag)->tagger, imsg.data + len,
985 			    itag->tagger_len);
986 			(*tag)->tagger[itag->tagger_len] = '\0';
987 		}
988 		len += itag->tagger_len;
989 
990 		if (itag->tagmsg_len == 0) {
991 			(*tag)->tagmsg = strdup("");
992 			if ((*tag)->tagmsg == NULL) {
993 				err = got_error_from_errno();
994 				break;
995 			}
996 		} else {
997 			size_t offset = 0, remain = itag->tagmsg_len;
998 
999 			(*tag)->tagmsg = malloc(itag->tagmsg_len + 1);
1000 			if ((*tag)->tagmsg == NULL) {
1001 				err = got_error_from_errno();
1002 				break;
1003 			}
1004 			while (remain > 0) {
1005 				struct imsg imsg_log;
1006 				size_t n = MIN(MAX_IMSGSIZE - IMSG_HEADER_SIZE,
1007 				    remain);
1008 
1009 				err = got_privsep_recv_imsg(&imsg_log, ibuf, n);
1010 				if (err)
1011 					return err;
1012 
1013 				if (imsg_log.hdr.type != GOT_IMSG_TAG_TAGMSG)
1014 					return got_error(GOT_ERR_PRIVSEP_MSG);
1015 
1016 				memcpy((*tag)->tagmsg + offset, imsg_log.data,
1017 				    n);
1018 				imsg_free(&imsg_log);
1019 				offset += n;
1020 				remain -= n;
1021 			}
1022 			(*tag)->tagmsg[itag->tagmsg_len] = '\0';
1023 		}
1024 
1025 		break;
1026 	default:
1027 		err = got_error(GOT_ERR_PRIVSEP_MSG);
1028 		break;
1029 	}
1030 
1031 	imsg_free(&imsg);
1032 
1033 	return err;
1034 }
1035 
1036 const struct got_error *
1037 got_privsep_init_pack_child(struct imsgbuf *ibuf, struct got_pack *pack,
1038     struct got_packidx *packidx)
1039 {
1040 	struct got_imsg_packidx ipackidx;
1041 	struct got_imsg_pack ipack;
1042 	int fd;
1043 
1044 	ipackidx.len = packidx->len;
1045 	fd = dup(packidx->fd);
1046 	if (fd == -1)
1047 		return got_error_from_errno();
1048 
1049 	if (imsg_compose(ibuf, GOT_IMSG_PACKIDX, 0, 0, fd, &ipackidx,
1050 	    sizeof(ipackidx)) == -1)
1051 		return got_error_from_errno();
1052 
1053 	if (strlcpy(ipack.path_packfile, pack->path_packfile,
1054 	    sizeof(ipack.path_packfile)) >= sizeof(ipack.path_packfile))
1055 		return got_error(GOT_ERR_NO_SPACE);
1056 	ipack.filesize = pack->filesize;
1057 
1058 	fd = dup(pack->fd);
1059 	if (fd == -1)
1060 		return got_error_from_errno();
1061 
1062 	if (imsg_compose(ibuf, GOT_IMSG_PACK, 0, 0, fd, &ipack, sizeof(ipack))
1063 	    == -1)
1064 		return got_error_from_errno();
1065 
1066 	return flush_imsg(ibuf);
1067 }
1068 
1069 const struct got_error *
1070 got_privsep_send_packed_obj_req(struct imsgbuf *ibuf, int idx,
1071     struct got_object_id *id)
1072 {
1073 	struct got_imsg_packed_object iobj;
1074 
1075 	iobj.idx = idx;
1076 	memcpy(iobj.id, id->sha1, sizeof(iobj.id));
1077 
1078 	if (imsg_compose(ibuf, GOT_IMSG_PACKED_OBJECT_REQUEST, 0, 0, -1,
1079 	    &iobj, sizeof(iobj)) == -1)
1080 		return got_error_from_errno();
1081 
1082 	return flush_imsg(ibuf);
1083 }