1 /*
2  * Copyright (c) 2022 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 "got_compat.h"
18 
19 #include <sys/queue.h>
20 #include <sys/time.h>
21 #include <sys/types.h>
22 #include <sys/stat.h>
23 #include <sys/socket.h>
24 #include <sys/un.h>
25 #include <sys/wait.h>
26 
27 #include <fcntl.h>
28 #include <err.h>
29 #include <errno.h>
30 #include <event.h>
31 #include <limits.h>
32 #include <pwd.h>
33 #include <imsg.h>
34 #include <signal.h>
35 #include <stdarg.h>
36 #include <stdio.h>
37 #include <stdlib.h>
38 #include <string.h>
39 #include <syslog.h>
40 #include <unistd.h>
41 
42 #include "got_error.h"
43 #include "got_opentemp.h"
44 #include "got_path.h"
45 #include "got_repository.h"
46 #include "got_object.h"
47 #include "got_reference.h"
48 
49 #include "got_lib_delta.h"
50 #include "got_lib_object.h"
51 #include "got_lib_object_cache.h"
52 #include "got_lib_hash.h"
53 #include "got_lib_gitproto.h"
54 #include "got_lib_pack.h"
55 #include "got_lib_repository.h"
56 
57 #include "gotd.h"
58 #include "log.h"
59 #include "listen.h"
60 #include "auth.h"
61 #include "session.h"
62 #include "repo_read.h"
63 #include "repo_write.h"
64 
65 #ifndef nitems
66 #define nitems(_a)	(sizeof((_a)) / sizeof((_a)[0]))
67 #endif
68 
69 enum gotd_client_state {
70 	GOTD_CLIENT_STATE_NEW,
71 	GOTD_CLIENT_STATE_ACCESS_GRANTED,
72 };
73 
74 struct gotd_child_proc {
75 	pid_t				 pid;
76 	enum gotd_procid		 type;
77 	char				 repo_name[NAME_MAX];
78 	char				 repo_path[PATH_MAX];
79 	int				 pipe[2];
80 	struct gotd_imsgev		 iev;
81 	struct event			 tmo;
82 
83 	TAILQ_ENTRY(gotd_child_proc)	 entry;
84 };
85 TAILQ_HEAD(gotd_procs, gotd_child_proc) procs;
86 
87 struct gotd_client {
88 	STAILQ_ENTRY(gotd_client)	 entry;
89 	enum gotd_client_state		 state;
90 	uint32_t			 id;
91 	int				 fd;
92 	struct gotd_imsgev		 iev;
93 	struct event			 tmo;
94 	uid_t				 euid;
95 	gid_t				 egid;
96 	struct gotd_child_proc		*repo;
97 	struct gotd_child_proc		*auth;
98 	struct gotd_child_proc		*session;
99 	int				 required_auth;
100 };
101 STAILQ_HEAD(gotd_clients, gotd_client);
102 
103 static struct gotd_clients gotd_clients[GOTD_CLIENT_TABLE_SIZE];
104 static SIPHASH_KEY clients_hash_key;
105 volatile int client_cnt;
106 static struct timeval auth_timeout = { 5, 0 };
107 static struct gotd gotd;
108 
109 void gotd_sighdlr(int sig, short event, void *arg);
110 static void gotd_shutdown(void);
111 static const struct got_error *start_session_child(struct gotd_client *,
112     struct gotd_repo *, char *, const char *, int, int);
113 static const struct got_error *start_repo_child(struct gotd_client *,
114     enum gotd_procid, struct gotd_repo *, char *, const char *, int, int);
115 static const struct got_error *start_auth_child(struct gotd_client *, int,
116     struct gotd_repo *, char *, const char *, int, int);
117 static void kill_proc(struct gotd_child_proc *, int);
118 static void disconnect(struct gotd_client *);
119 static void drop_privs(struct passwd *);
120 
121 __dead static void
122 usage(void)
123 {
124 	fprintf(stderr, "usage: %s [-dnv] [-f config-file]\n", getprogname());
125 	exit(1);
126 }
127 
128 static int
129 unix_socket_listen(const char *unix_socket_path, uid_t uid, gid_t gid)
130 {
131 	struct sockaddr_un sun;
132 	int fd = -1;
133 	mode_t old_umask, mode;
134 	int sock_flags = SOCK_STREAM | SOCK_NONBLOCK;
135 
136 #ifdef SOCK_CLOEXEC
137 	sock_flags |= SOCK_CLOEXEC;
138 #endif
139 
140 	fd = socket(AF_UNIX, sock_flags, 0);
141 	if (fd == -1) {
142 		log_warn("socket");
143 		return -1;
144 	}
145 
146 	sun.sun_family = AF_UNIX;
147 	if (strlcpy(sun.sun_path, unix_socket_path,
148 	    sizeof(sun.sun_path)) >= sizeof(sun.sun_path)) {
149 		log_warnx("%s: name too long", unix_socket_path);
150 		close(fd);
151 		return -1;
152 	}
153 
154 	if (unlink(unix_socket_path) == -1) {
155 		if (errno != ENOENT) {
156 			log_warn("unlink %s", unix_socket_path);
157 			close(fd);
158 			return -1;
159 		}
160 	}
161 
162 	old_umask = umask(S_IXUSR|S_IXGRP|S_IWOTH|S_IROTH|S_IXOTH);
163 	mode = S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH;
164 
165 	if (bind(fd, (struct sockaddr *)&sun, sizeof(sun)) == -1) {
166 		log_warn("bind: %s", unix_socket_path);
167 		close(fd);
168 		umask(old_umask);
169 		return -1;
170 	}
171 
172 	umask(old_umask);
173 
174 	if (chmod(unix_socket_path, mode) == -1) {
175 		log_warn("chmod %o %s", mode, unix_socket_path);
176 		close(fd);
177 		unlink(unix_socket_path);
178 		return -1;
179 	}
180 
181 	if (chown(unix_socket_path, uid, gid) == -1) {
182 		log_warn("chown %s uid=%d gid=%d", unix_socket_path, uid, gid);
183 		close(fd);
184 		unlink(unix_socket_path);
185 		return -1;
186 	}
187 
188 	if (listen(fd, GOTD_UNIX_SOCKET_BACKLOG) == -1) {
189 		log_warn("listen");
190 		close(fd);
191 		unlink(unix_socket_path);
192 		return -1;
193 	}
194 
195 	return fd;
196 }
197 
198 static uint64_t
199 client_hash(uint32_t client_id)
200 {
201 	return SipHash24(&clients_hash_key, &client_id, sizeof(client_id));
202 }
203 
204 static void
205 add_client(struct gotd_client *client)
206 {
207 	uint64_t slot = client_hash(client->id) % nitems(gotd_clients);
208 	STAILQ_INSERT_HEAD(&gotd_clients[slot], client, entry);
209 	client_cnt++;
210 }
211 
212 static struct gotd_client *
213 find_client(uint32_t client_id)
214 {
215 	uint64_t slot;
216 	struct gotd_client *c;
217 
218 	slot = client_hash(client_id) % nitems(gotd_clients);
219 	STAILQ_FOREACH(c, &gotd_clients[slot], entry) {
220 		if (c->id == client_id)
221 			return c;
222 	}
223 
224 	return NULL;
225 }
226 
227 static struct gotd_client *
228 find_client_by_proc_fd(int fd)
229 {
230 	uint64_t slot;
231 
232 	for (slot = 0; slot < nitems(gotd_clients); slot++) {
233 		struct gotd_client *c;
234 
235 		STAILQ_FOREACH(c, &gotd_clients[slot], entry) {
236 			if (c->repo && c->repo->iev.ibuf.fd == fd)
237 				return c;
238 			if (c->auth && c->auth->iev.ibuf.fd == fd)
239 				return c;
240 			if (c->session && c->session->iev.ibuf.fd == fd)
241 				return c;
242 		}
243 	}
244 
245 	return NULL;
246 }
247 
248 static int
249 client_is_reading(struct gotd_client *client)
250 {
251 	return (client->required_auth &
252 	    (GOTD_AUTH_READ | GOTD_AUTH_WRITE)) == GOTD_AUTH_READ;
253 }
254 
255 static int
256 client_is_writing(struct gotd_client *client)
257 {
258 	return (client->required_auth &
259 	    (GOTD_AUTH_READ | GOTD_AUTH_WRITE)) ==
260 	    (GOTD_AUTH_READ | GOTD_AUTH_WRITE);
261 }
262 
263 static const struct got_error *
264 ensure_client_is_not_writing(struct gotd_client *client)
265 {
266 	if (client_is_writing(client)) {
267 		return got_error_fmt(GOT_ERR_BAD_PACKET,
268 		    "uid %d made a read-request but is writing to "
269 		    "a repository", client->euid);
270 	}
271 
272 	return NULL;
273 }
274 
275 static const struct got_error *
276 ensure_client_is_not_reading(struct gotd_client *client)
277 {
278 	if (client_is_reading(client)) {
279 		return got_error_fmt(GOT_ERR_BAD_PACKET,
280 		    "uid %d made a write-request but is reading from "
281 		    "a repository", client->euid);
282 	}
283 
284 	return NULL;
285 }
286 
287 static void
288 proc_done(struct gotd_child_proc *proc)
289 {
290 	struct gotd_client *client;
291 
292 	TAILQ_REMOVE(&procs, proc, entry);
293 
294 	client = find_client_by_proc_fd(proc->iev.ibuf.fd);
295 	if (client != NULL) {
296 		if (proc == client->repo)
297 			client->repo = NULL;
298 		if (proc == client->auth)
299 			client->auth = NULL;
300 		if (proc == client->session)
301 			client->session = NULL;
302 		disconnect(client);
303 	}
304 
305 	evtimer_del(&proc->tmo);
306 
307 	if (proc->iev.ibuf.fd != -1) {
308 		event_del(&proc->iev.ev);
309 		msgbuf_clear(&proc->iev.ibuf.w);
310 		close(proc->iev.ibuf.fd);
311 	}
312 
313 	free(proc);
314 }
315 
316 static void
317 kill_repo_proc(struct gotd_client *client)
318 {
319 	if (client->repo == NULL)
320 		return;
321 
322 	kill_proc(client->repo, 0);
323 	client->repo = NULL;
324 }
325 
326 static void
327 kill_auth_proc(struct gotd_client *client)
328 {
329 	if (client->auth == NULL)
330 		return;
331 
332 	kill_proc(client->auth, 0);
333 	client->auth = NULL;
334 }
335 
336 static void
337 kill_session_proc(struct gotd_client *client)
338 {
339 	if (client->session == NULL)
340 		return;
341 
342 	kill_proc(client->session, 0);
343 	client->session = NULL;
344 }
345 
346 static void
347 disconnect(struct gotd_client *client)
348 {
349 	struct gotd_imsg_disconnect idisconnect;
350 	struct gotd_child_proc *listen_proc = gotd.listen_proc;
351 	uint64_t slot;
352 
353 	log_debug("uid %d: disconnecting", client->euid);
354 
355 	kill_auth_proc(client);
356 	kill_session_proc(client);
357 	kill_repo_proc(client);
358 
359 	idisconnect.client_id = client->id;
360 	if (gotd_imsg_compose_event(&listen_proc->iev,
361 	    GOTD_IMSG_DISCONNECT, PROC_GOTD, -1,
362 	    &idisconnect, sizeof(idisconnect)) == -1)
363 		log_warn("imsg compose DISCONNECT");
364 
365 	slot = client_hash(client->id) % nitems(gotd_clients);
366 	STAILQ_REMOVE(&gotd_clients[slot], client, gotd_client, entry);
367 	imsg_clear(&client->iev.ibuf);
368 	event_del(&client->iev.ev);
369 	evtimer_del(&client->tmo);
370 	if (client->fd != -1)
371 		close(client->fd);
372 	else if (client->iev.ibuf.fd != -1)
373 		close(client->iev.ibuf.fd);
374 	free(client);
375 	client_cnt--;
376 }
377 
378 static void
379 disconnect_on_error(struct gotd_client *client, const struct got_error *err)
380 {
381 	struct imsgbuf ibuf;
382 
383 	if (err->code != GOT_ERR_EOF) {
384 		log_warnx("uid %d: %s", client->euid, err->msg);
385 		if (client->fd != -1) {
386 			imsg_init(&ibuf, client->fd);
387 			gotd_imsg_send_error(&ibuf, 0, PROC_GOTD, err);
388 			imsg_clear(&ibuf);
389 		}
390 	}
391 	disconnect(client);
392 }
393 
394 static const struct got_error *
395 send_repo_info(struct gotd_imsgev *iev, struct gotd_repo *repo)
396 {
397 	const struct got_error *err = NULL;
398 	struct gotd_imsg_info_repo irepo;
399 
400 	memset(&irepo, 0, sizeof(irepo));
401 
402 	if (strlcpy(irepo.repo_name, repo->name, sizeof(irepo.repo_name))
403 	    >= sizeof(irepo.repo_name))
404 		return got_error_msg(GOT_ERR_NO_SPACE, "repo name too long");
405 	if (strlcpy(irepo.repo_path, repo->path, sizeof(irepo.repo_path))
406 	    >= sizeof(irepo.repo_path))
407 		return got_error_msg(GOT_ERR_NO_SPACE, "repo path too long");
408 
409 	if (gotd_imsg_compose_event(iev, GOTD_IMSG_INFO_REPO, PROC_GOTD, -1,
410 	    &irepo, sizeof(irepo)) == -1) {
411 		err = got_error_from_errno("imsg compose INFO_REPO");
412 		if (err)
413 			return err;
414 	}
415 
416 	return NULL;
417 }
418 
419 static const struct got_error *
420 send_client_info(struct gotd_imsgev *iev, struct gotd_client *client)
421 {
422 	const struct got_error *err = NULL;
423 	struct gotd_imsg_info_client iclient;
424 	struct gotd_child_proc *proc;
425 
426 	memset(&iclient, 0, sizeof(iclient));
427 	iclient.euid = client->euid;
428 	iclient.egid = client->egid;
429 
430 	proc = client->repo;
431 	if (proc) {
432 		if (strlcpy(iclient.repo_name, proc->repo_path,
433 		    sizeof(iclient.repo_name)) >= sizeof(iclient.repo_name)) {
434 			return got_error_msg(GOT_ERR_NO_SPACE,
435 			    "repo name too long");
436 		}
437 		if (client_is_writing(client))
438 			iclient.is_writing = 1;
439 
440 		iclient.repo_child_pid = proc->pid;
441 	}
442 
443 	if (client->session)
444 		iclient.session_child_pid = client->session->pid;
445 
446 	if (gotd_imsg_compose_event(iev, GOTD_IMSG_INFO_CLIENT, PROC_GOTD, -1,
447 	    &iclient, sizeof(iclient)) == -1) {
448 		err = got_error_from_errno("imsg compose INFO_CLIENT");
449 		if (err)
450 			return err;
451 	}
452 
453 	return NULL;
454 }
455 
456 static const struct got_error *
457 send_info(struct gotd_client *client)
458 {
459 	const struct got_error *err = NULL;
460 	struct gotd_imsg_info info;
461 	uint64_t slot;
462 	struct gotd_repo *repo;
463 
464 	if (client->euid != 0)
465 		return got_error_set_errno(EPERM, "info");
466 
467 	info.pid = gotd.pid;
468 	info.verbosity = gotd.verbosity;
469 	info.nrepos = gotd.nrepos;
470 	info.nclients = client_cnt - 1;
471 
472 	if (gotd_imsg_compose_event(&client->iev, GOTD_IMSG_INFO, PROC_GOTD, -1,
473 	    &info, sizeof(info)) == -1) {
474 		err = got_error_from_errno("imsg compose INFO");
475 		if (err)
476 			return err;
477 	}
478 
479 	TAILQ_FOREACH(repo, &gotd.repos, entry) {
480 		err = send_repo_info(&client->iev, repo);
481 		if (err)
482 			return err;
483 	}
484 
485 	for (slot = 0; slot < nitems(gotd_clients); slot++) {
486 		struct gotd_client *c;
487 		STAILQ_FOREACH(c, &gotd_clients[slot], entry) {
488 			if (c->id == client->id)
489 				continue;
490 			err = send_client_info(&client->iev, c);
491 			if (err)
492 				return err;
493 		}
494 	}
495 
496 	return NULL;
497 }
498 
499 static const struct got_error *
500 stop_gotd(struct gotd_client *client)
501 {
502 
503 	if (client->euid != 0)
504 		return got_error_set_errno(EPERM, "stop");
505 
506 	gotd_shutdown();
507 	/* NOTREACHED */
508 	return NULL;
509 }
510 
511 static const struct got_error *
512 start_client_authentication(struct gotd_client *client, struct imsg *imsg)
513 {
514 	const struct got_error *err;
515 	struct gotd_imsg_list_refs ireq;
516 	struct gotd_repo *repo = NULL;
517 	size_t datalen;
518 
519 	log_debug("list-refs request from uid %d", client->euid);
520 
521 	if (client->state != GOTD_CLIENT_STATE_NEW)
522 		return got_error_msg(GOT_ERR_BAD_REQUEST,
523 		    "unexpected list-refs request received");
524 
525 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
526 	if (datalen != sizeof(ireq))
527 		return got_error(GOT_ERR_PRIVSEP_LEN);
528 
529 	memcpy(&ireq, imsg->data, datalen);
530 
531 	if (ireq.client_is_reading) {
532 		err = ensure_client_is_not_writing(client);
533 		if (err)
534 			return err;
535 		repo = gotd_find_repo_by_name(ireq.repo_name, &gotd);
536 		if (repo == NULL)
537 			return got_error(GOT_ERR_NOT_GIT_REPO);
538 		err = start_auth_child(client, GOTD_AUTH_READ, repo,
539 		    gotd.argv0, gotd.confpath, gotd.daemonize,
540 		    gotd.verbosity);
541 		if (err)
542 			return err;
543 	} else {
544 		err = ensure_client_is_not_reading(client);
545 		if (err)
546 			return err;
547 		repo = gotd_find_repo_by_name(ireq.repo_name, &gotd);
548 		if (repo == NULL)
549 			return got_error(GOT_ERR_NOT_GIT_REPO);
550 		err = start_auth_child(client,
551 		    GOTD_AUTH_READ | GOTD_AUTH_WRITE,
552 		    repo, gotd.argv0, gotd.confpath, gotd.daemonize,
553 		    gotd.verbosity);
554 		if (err)
555 			return err;
556 	}
557 
558 	evtimer_add(&client->tmo, &auth_timeout);
559 
560 	/* Flow continues upon authentication success/failure or timeout. */
561 	return NULL;
562 }
563 
564 static void
565 gotd_request(int fd, short events, void *arg)
566 {
567 	struct gotd_imsgev *iev = arg;
568 	struct imsgbuf *ibuf = &iev->ibuf;
569 	struct gotd_client *client = iev->handler_arg;
570 	const struct got_error *err = NULL;
571 	struct imsg imsg;
572 	ssize_t n;
573 
574 	if (events & EV_WRITE) {
575 		while (ibuf->w.queued) {
576 			n = msgbuf_write(&ibuf->w);
577 			if (n == -1 && errno == EPIPE) {
578 				/*
579 				 * The client has closed its socket.
580 				 * This can happen when Git clients are
581 				 * done sending pack file data.
582 				 */
583 				msgbuf_clear(&ibuf->w);
584 				continue;
585 			} else if (n == -1 && errno != EAGAIN) {
586 				err = got_error_from_errno("imsg_flush");
587 				disconnect_on_error(client, err);
588 				return;
589 			}
590 			if (n == 0) {
591 				/* Connection closed. */
592 				err = got_error(GOT_ERR_EOF);
593 				disconnect_on_error(client, err);
594 				return;
595 			}
596 		}
597 
598 		/* Disconnect gotctl(8) now that messages have been sent. */
599 		if (!client_is_reading(client) && !client_is_writing(client)) {
600 			disconnect(client);
601 			return;
602 		}
603 	}
604 
605 	if ((events & EV_READ) == 0)
606 		return;
607 
608 	memset(&imsg, 0, sizeof(imsg));
609 
610 	while (err == NULL) {
611 		err = gotd_imsg_recv(&imsg, ibuf, 0);
612 		if (err) {
613 			if (err->code == GOT_ERR_PRIVSEP_READ)
614 				err = NULL;
615 			break;
616 		}
617 
618 		evtimer_del(&client->tmo);
619 
620 		switch (imsg.hdr.type) {
621 		case GOTD_IMSG_INFO:
622 			err = send_info(client);
623 			break;
624 		case GOTD_IMSG_STOP:
625 			err = stop_gotd(client);
626 			break;
627 		case GOTD_IMSG_LIST_REFS:
628 			err = start_client_authentication(client, &imsg);
629 			break;
630 		default:
631 			log_debug("unexpected imsg %d", imsg.hdr.type);
632 			err = got_error(GOT_ERR_PRIVSEP_MSG);
633 			break;
634 		}
635 
636 		imsg_free(&imsg);
637 	}
638 
639 	if (err) {
640 		disconnect_on_error(client, err);
641 	} else {
642 		gotd_imsg_event_add(&client->iev);
643 	}
644 }
645 
646 static void
647 gotd_auth_timeout(int fd, short events, void *arg)
648 {
649 	struct gotd_client *client = arg;
650 
651 	log_debug("disconnecting uid %d due to authentication timeout",
652 	    client->euid);
653 	disconnect(client);
654 }
655 
656 static const struct got_error *
657 recv_connect(uint32_t *client_id, struct imsg *imsg)
658 {
659 	const struct got_error *err = NULL;
660 	struct gotd_imsg_connect iconnect;
661 	size_t datalen;
662 	int s = -1;
663 	struct gotd_client *client = NULL;
664 
665 	*client_id = 0;
666 
667 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
668 	if (datalen != sizeof(iconnect))
669 		return got_error(GOT_ERR_PRIVSEP_LEN);
670 	memcpy(&iconnect, imsg->data, sizeof(iconnect));
671 
672 	s = imsg->fd;
673 	if (s == -1) {
674 		err = got_error(GOT_ERR_PRIVSEP_NO_FD);
675 		goto done;
676 	}
677 
678 	if (find_client(iconnect.client_id)) {
679 		err = got_error_msg(GOT_ERR_CLIENT_ID, "duplicate client ID");
680 		goto done;
681 	}
682 
683 	client = calloc(1, sizeof(*client));
684 	if (client == NULL) {
685 		err = got_error_from_errno("calloc");
686 		goto done;
687 	}
688 
689 	*client_id = iconnect.client_id;
690 
691 	client->state = GOTD_CLIENT_STATE_NEW;
692 	client->id = iconnect.client_id;
693 	client->fd = s;
694 	s = -1;
695 	/* The auth process will verify UID/GID for us. */
696 	client->euid = iconnect.euid;
697 	client->egid = iconnect.egid;
698 
699 	imsg_init(&client->iev.ibuf, client->fd);
700 	client->iev.handler = gotd_request;
701 	client->iev.events = EV_READ;
702 	client->iev.handler_arg = client;
703 
704 	event_set(&client->iev.ev, client->fd, EV_READ, gotd_request,
705 	    &client->iev);
706 	gotd_imsg_event_add(&client->iev);
707 
708 	evtimer_set(&client->tmo, gotd_auth_timeout, client);
709 
710 	add_client(client);
711 	log_debug("%s: new client uid %d connected on fd %d", __func__,
712 	    client->euid, client->fd);
713 done:
714 	if (err) {
715 		struct gotd_child_proc *listen_proc = gotd.listen_proc;
716 		struct gotd_imsg_disconnect idisconnect;
717 
718 		idisconnect.client_id = client->id;
719 		if (gotd_imsg_compose_event(&listen_proc->iev,
720 		    GOTD_IMSG_DISCONNECT, PROC_GOTD, -1,
721 		    &idisconnect, sizeof(idisconnect)) == -1)
722 			log_warn("imsg compose DISCONNECT");
723 
724 		if (s != -1)
725 			close(s);
726 	}
727 
728 	return err;
729 }
730 
731 static const char *gotd_proc_names[PROC_MAX] = {
732 	"parent",
733 	"listen",
734 	"auth",
735 	"session_read",
736 	"session_write",
737 	"repo_read",
738 	"repo_write",
739 	"gitwrapper"
740 };
741 
742 static void
743 kill_proc(struct gotd_child_proc *proc, int fatal)
744 {
745 	struct timeval tv = { 5, 0 };
746 
747 	log_debug("kill -%d %d", fatal ? SIGKILL : SIGTERM, proc->pid);
748 
749 	if (proc->iev.ibuf.fd != -1) {
750 		event_del(&proc->iev.ev);
751 		msgbuf_clear(&proc->iev.ibuf.w);
752 		close(proc->iev.ibuf.fd);
753 		proc->iev.ibuf.fd = -1;
754 	}
755 
756 	if (!evtimer_pending(&proc->tmo, NULL) && !fatal)
757 		evtimer_add(&proc->tmo, &tv);
758 
759 	if (fatal) {
760 		log_warnx("sending SIGKILL to PID %d", proc->pid);
761 		kill(proc->pid, SIGKILL);
762 	} else
763 		kill(proc->pid, SIGTERM);
764 }
765 
766 static void
767 kill_proc_timeout(int fd, short ev, void *d)
768 {
769 	struct gotd_child_proc *proc = d;
770 
771 	log_warnx("timeout waiting for PID %d to terminate;"
772 	    " retrying with force", proc->pid);
773 	kill_proc(proc, 1);
774 }
775 
776 static void
777 gotd_shutdown(void)
778 {
779 	uint64_t slot;
780 
781 	log_debug("shutting down");
782 	for (slot = 0; slot < nitems(gotd_clients); slot++) {
783 		struct gotd_client *c, *tmp;
784 
785 		STAILQ_FOREACH_SAFE(c, &gotd_clients[slot], entry, tmp)
786 			disconnect(c);
787 	}
788 
789 	kill_proc(gotd.listen_proc, 0);
790 
791 	log_info("terminating");
792 	exit(0);
793 }
794 
795 static struct gotd_child_proc *
796 find_proc_by_pid(pid_t pid)
797 {
798 	struct gotd_child_proc *proc = NULL;
799 
800 	TAILQ_FOREACH(proc, &procs, entry)
801 		if (proc->pid == pid)
802 			break;
803 
804 	return proc;
805 }
806 
807 void
808 gotd_sighdlr(int sig, short event, void *arg)
809 {
810 	struct gotd_child_proc *proc;
811 	pid_t pid;
812 	int status;
813 
814 	/*
815 	 * Normal signal handler rules don't apply because libevent
816 	 * decouples for us.
817 	 */
818 
819 	switch (sig) {
820 	case SIGHUP:
821 		log_info("%s: ignoring SIGHUP", __func__);
822 		break;
823 	case SIGUSR1:
824 		log_info("%s: ignoring SIGUSR1", __func__);
825 		break;
826 	case SIGTERM:
827 	case SIGINT:
828 		gotd_shutdown();
829 		break;
830 	case SIGCHLD:
831 		for (;;) {
832 			pid = waitpid(WAIT_ANY, &status, WNOHANG);
833 			if (pid == -1) {
834 				if (errno == EINTR)
835 					continue;
836 				if (errno == ECHILD)
837 					break;
838 				fatal("waitpid");
839 			}
840 			if (pid == 0)
841 				break;
842 
843 			log_debug("reaped pid %d", pid);
844 			proc = find_proc_by_pid(pid);
845 			if (proc == NULL) {
846 				log_info("caught exit of unknown child %d",
847 				    pid);
848 				continue;
849 			}
850 
851 			if (WIFSIGNALED(status)) {
852 				log_warnx("child PID %d terminated with"
853 				    " signal %d", pid, WTERMSIG(status));
854 			}
855 
856 			proc_done(proc);
857 		}
858 		break;
859 	default:
860 		fatalx("unexpected signal");
861 	}
862 }
863 
864 static const struct got_error *
865 ensure_proc_is_reading(struct gotd_client *client,
866     struct gotd_child_proc *proc)
867 {
868 	if (!client_is_reading(client)) {
869 		kill_proc(proc, 1);
870 		return got_error_fmt(GOT_ERR_BAD_PACKET,
871 		    "PID %d handled a read-request for uid %d but this "
872 		    "user is not reading from a repository", proc->pid,
873 		    client->euid);
874 	}
875 
876 	return NULL;
877 }
878 
879 static const struct got_error *
880 ensure_proc_is_writing(struct gotd_client *client,
881     struct gotd_child_proc *proc)
882 {
883 	if (!client_is_writing(client)) {
884 		kill_proc(proc, 1);
885 		return got_error_fmt(GOT_ERR_BAD_PACKET,
886 		    "PID %d handled a write-request for uid %d but this "
887 		    "user is not writing to a repository", proc->pid,
888 		    client->euid);
889 	}
890 
891 	return NULL;
892 }
893 
894 static int
895 verify_imsg_src(struct gotd_client *client, struct gotd_child_proc *proc,
896     struct imsg *imsg)
897 {
898 	const struct got_error *err;
899 	int ret = 0;
900 
901 	if (proc->type == PROC_REPO_READ || proc->type == PROC_REPO_WRITE) {
902 		if (client->repo == NULL)
903 			fatalx("no process found for uid %d", client->euid);
904 		if (proc->pid != client->repo->pid) {
905 			kill_proc(proc, 1);
906 			log_warnx("received message from PID %d for uid %d, "
907 			    "while PID %d is the process serving this user",
908 			    proc->pid, client->euid, client->repo->pid);
909 			return 0;
910 		}
911 	}
912 	if (proc->type == PROC_SESSION_READ ||
913 	    proc->type == PROC_SESSION_WRITE) {
914 		if (client->session == NULL) {
915 			log_warnx("no session found for uid %d", client->euid);
916 			return 0;
917 		}
918 		if (proc->pid != client->session->pid) {
919 			kill_proc(proc, 1);
920 			log_warnx("received message from PID %d for uid %d, "
921 			    "while PID %d is the process serving this user",
922 			    proc->pid, client->euid, client->session->pid);
923 			return 0;
924 		}
925 	}
926 
927 	switch (imsg->hdr.type) {
928 	case GOTD_IMSG_ERROR:
929 		ret = 1;
930 		break;
931 	case GOTD_IMSG_CONNECT:
932 		if (proc->type != PROC_LISTEN) {
933 			err = got_error_fmt(GOT_ERR_BAD_PACKET,
934 			    "new connection for uid %d from PID %d "
935 			    "which is not the listen process",
936 			    proc->pid, client->euid);
937 		} else
938 			ret = 1;
939 		break;
940 	case GOTD_IMSG_ACCESS_GRANTED:
941 		if (proc->type != PROC_AUTH) {
942 			err = got_error_fmt(GOT_ERR_BAD_PACKET,
943 			    "authentication of uid %d from PID %d "
944 			    "which is not the auth process",
945 			    proc->pid, client->euid);
946 		} else
947 			ret = 1;
948 		break;
949 	case GOTD_IMSG_CLIENT_SESSION_READY:
950 		if (proc->type != PROC_SESSION_READ &&
951 		    proc->type != PROC_SESSION_WRITE) {
952 			err = got_error_fmt(GOT_ERR_BAD_PACKET,
953 			    "unexpected \"ready\" signal from PID %d",
954 			    proc->pid);
955 		} else
956 			ret = 1;
957 		break;
958 	case GOTD_IMSG_REPO_CHILD_READY:
959 		if (proc->type != PROC_REPO_READ &&
960 		    proc->type != PROC_REPO_WRITE) {
961 			err = got_error_fmt(GOT_ERR_BAD_PACKET,
962 			    "unexpected \"ready\" signal from PID %d",
963 			    proc->pid);
964 		} else
965 			ret = 1;
966 		break;
967 	case GOTD_IMSG_PACKFILE_DONE:
968 		err = ensure_proc_is_reading(client, proc);
969 		if (err)
970 			log_warnx("uid %d: %s", client->euid, err->msg);
971 		else
972 			ret = 1;
973 		break;
974 	case GOTD_IMSG_PACKFILE_INSTALL:
975 	case GOTD_IMSG_REF_UPDATES_START:
976 	case GOTD_IMSG_REF_UPDATE:
977 		err = ensure_proc_is_writing(client, proc);
978 		if (err)
979 			log_warnx("uid %d: %s", client->euid, err->msg);
980 		else
981 			ret = 1;
982 		break;
983 	default:
984 		log_debug("%s: unexpected imsg %d", __func__, imsg->hdr.type);
985 		break;
986 	}
987 
988 	return ret;
989 }
990 
991 static const struct got_error *
992 connect_repo_child(struct gotd_client *client,
993     struct gotd_child_proc *repo_proc)
994 {
995 	static const struct got_error *err;
996 	struct gotd_imsgev *session_iev = &client->session->iev;
997 	struct gotd_imsg_connect_repo_child ireq;
998 	int pipe[2];
999 	int sock_flags = SOCK_STREAM | SOCK_NONBLOCK;
1000 
1001 #ifdef SOCK_CLOEXEC
1002 	sock_flags |= SOCK_CLOEXEC;
1003 #endif
1004 
1005 	if (client->state != GOTD_CLIENT_STATE_ACCESS_GRANTED)
1006 		return got_error_msg(GOT_ERR_BAD_REQUEST,
1007 		    "unexpected repo child ready signal received");
1008 
1009 	if (socketpair(AF_UNIX, sock_flags, PF_UNSPEC, pipe) == -1)
1010 		fatal("socketpair");
1011 
1012 	memset(&ireq, 0, sizeof(ireq));
1013 	ireq.client_id = client->id;
1014 	ireq.proc_id = repo_proc->type;
1015 
1016 	/* Pass repo child pipe to session child process. */
1017 	if (gotd_imsg_compose_event(session_iev, GOTD_IMSG_CONNECT_REPO_CHILD,
1018 	    PROC_GOTD, pipe[0], &ireq, sizeof(ireq)) == -1) {
1019 		err = got_error_from_errno("imsg compose CONNECT_REPO_CHILD");
1020 		close(pipe[0]);
1021 		close(pipe[1]);
1022 		return err;
1023 	}
1024 
1025 	/* Pass session child pipe to repo child process. */
1026 	if (gotd_imsg_compose_event(&repo_proc->iev,
1027 	    GOTD_IMSG_CONNECT_REPO_CHILD, PROC_GOTD, pipe[1], NULL, 0) == -1) {
1028 		err = got_error_from_errno("imsg compose CONNECT_REPO_CHILD");
1029 		close(pipe[1]);
1030 		return err;
1031 	}
1032 
1033 	return NULL;
1034 }
1035 
1036 static void
1037 gotd_dispatch_listener(int fd, short event, void *arg)
1038 {
1039 	struct gotd_imsgev *iev = arg;
1040 	struct imsgbuf *ibuf = &iev->ibuf;
1041 	struct gotd_child_proc *proc = gotd.listen_proc;
1042 	ssize_t n;
1043 	int shut = 0;
1044 	struct imsg imsg;
1045 
1046 	if (proc->iev.ibuf.fd != fd)
1047 		fatalx("%s: unexpected fd %d", __func__, fd);
1048 
1049 	if (event & EV_READ) {
1050 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
1051 			fatal("imsg_read error");
1052 		if (n == 0) {
1053 			/* Connection closed. */
1054 			shut = 1;
1055 			goto done;
1056 		}
1057 	}
1058 
1059 	if (event & EV_WRITE) {
1060 		n = msgbuf_write(&ibuf->w);
1061 		if (n == -1 && errno != EAGAIN)
1062 			fatal("msgbuf_write");
1063 		if (n == 0) {
1064 			/* Connection closed. */
1065 			shut = 1;
1066 			goto done;
1067 		}
1068 	}
1069 
1070 	for (;;) {
1071 		const struct got_error *err = NULL;
1072 		struct gotd_client *client = NULL;
1073 		uint32_t client_id = 0;
1074 		int do_disconnect = 0;
1075 
1076 		if ((n = imsg_get(ibuf, &imsg)) == -1)
1077 			fatal("%s: imsg_get error", __func__);
1078 		if (n == 0)	/* No more messages. */
1079 			break;
1080 
1081 		switch (imsg.hdr.type) {
1082 		case GOTD_IMSG_ERROR:
1083 			do_disconnect = 1;
1084 			err = gotd_imsg_recv_error(&client_id, &imsg);
1085 			break;
1086 		case GOTD_IMSG_CONNECT:
1087 			err = recv_connect(&client_id, &imsg);
1088 			break;
1089 		default:
1090 			log_debug("unexpected imsg %d", imsg.hdr.type);
1091 			break;
1092 		}
1093 
1094 		client = find_client(client_id);
1095 		if (client == NULL) {
1096 			log_warnx("%s: client not found", __func__);
1097 			imsg_free(&imsg);
1098 			continue;
1099 		}
1100 
1101 		if (err)
1102 			log_warnx("uid %d: %s", client->euid, err->msg);
1103 
1104 		if (do_disconnect) {
1105 			if (err)
1106 				disconnect_on_error(client, err);
1107 			else
1108 				disconnect(client);
1109 		}
1110 
1111 		imsg_free(&imsg);
1112 	}
1113 done:
1114 	if (!shut) {
1115 		gotd_imsg_event_add(iev);
1116 	} else {
1117 		/* This pipe is dead. Remove its event handler */
1118 		event_del(&iev->ev);
1119 		event_loopexit(NULL);
1120 	}
1121 }
1122 
1123 static void
1124 gotd_dispatch_auth_child(int fd, short event, void *arg)
1125 {
1126 	const struct got_error *err = NULL;
1127 	struct gotd_imsgev *iev = arg;
1128 	struct imsgbuf *ibuf = &iev->ibuf;
1129 	struct gotd_client *client;
1130 	struct gotd_repo *repo = NULL;
1131 	ssize_t n;
1132 	int shut = 0;
1133 	struct imsg imsg;
1134 	uint32_t client_id = 0;
1135 	int do_disconnect = 0;
1136 
1137 	client = find_client_by_proc_fd(fd);
1138 	if (client == NULL) {
1139 		/* Can happen during process teardown. */
1140 		warnx("cannot find client for fd %d", fd);
1141 		shut = 1;
1142 		goto done;
1143 	}
1144 
1145 	if (client->auth == NULL)
1146 		fatalx("cannot find auth child process for fd %d", fd);
1147 
1148 	if (event & EV_READ) {
1149 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
1150 			fatal("imsg_read error");
1151 		if (n == 0) {
1152 			/* Connection closed. */
1153 			shut = 1;
1154 			goto done;
1155 		}
1156 	}
1157 
1158 	if (event & EV_WRITE) {
1159 		n = msgbuf_write(&ibuf->w);
1160 		if (n == -1 && errno != EAGAIN)
1161 			fatal("msgbuf_write");
1162 		if (n == 0) {
1163 			/* Connection closed. */
1164 			shut = 1;
1165 		}
1166 		goto done;
1167 	}
1168 
1169 	if (client->auth->iev.ibuf.fd != fd)
1170 		fatalx("%s: unexpected fd %d", __func__, fd);
1171 
1172 	if ((n = imsg_get(ibuf, &imsg)) == -1)
1173 		fatal("%s: imsg_get error", __func__);
1174 	if (n == 0)	/* No more messages. */
1175 		return;
1176 
1177 	evtimer_del(&client->tmo);
1178 
1179 	switch (imsg.hdr.type) {
1180 	case GOTD_IMSG_ERROR:
1181 		do_disconnect = 1;
1182 		err = gotd_imsg_recv_error(&client_id, &imsg);
1183 		break;
1184 	case GOTD_IMSG_ACCESS_GRANTED:
1185 		client->state = GOTD_CLIENT_STATE_ACCESS_GRANTED;
1186 		break;
1187 	default:
1188 		do_disconnect = 1;
1189 		log_debug("unexpected imsg %d", imsg.hdr.type);
1190 		break;
1191 	}
1192 
1193 	if (!verify_imsg_src(client, client->auth, &imsg)) {
1194 		do_disconnect = 1;
1195 		log_debug("dropping imsg type %d from PID %d",
1196 		    imsg.hdr.type, client->auth->pid);
1197 	}
1198 	imsg_free(&imsg);
1199 
1200 	if (do_disconnect) {
1201 		if (err)
1202 			disconnect_on_error(client, err);
1203 		else
1204 			disconnect(client);
1205 		return;
1206 	}
1207 
1208 	repo = gotd_find_repo_by_name(client->auth->repo_name, &gotd);
1209 	if (repo == NULL) {
1210 		err = got_error(GOT_ERR_NOT_GIT_REPO);
1211 		goto done;
1212 	}
1213 	kill_auth_proc(client);
1214 
1215 	log_info("authenticated uid %d for repository %s",
1216 	    client->euid, repo->name);
1217 
1218 	err = start_session_child(client, repo, gotd.argv0,
1219 	    gotd.confpath, gotd.daemonize, gotd.verbosity);
1220 	if (err)
1221 		goto done;
1222 done:
1223 	if (err)
1224 		log_warnx("uid %d: %s", client->euid, err->msg);
1225 
1226 	/* We might have killed the auth process by now. */
1227 	if (client->auth != NULL) {
1228 		if (!shut) {
1229 			gotd_imsg_event_add(iev);
1230 		} else {
1231 			/* This pipe is dead. Remove its event handler */
1232 			event_del(&iev->ev);
1233 		}
1234 	}
1235 }
1236 
1237 static const struct got_error *
1238 connect_session(struct gotd_client *client)
1239 {
1240 	const struct got_error *err = NULL;
1241 	struct gotd_imsg_connect iconnect;
1242 	int s;
1243 
1244 	memset(&iconnect, 0, sizeof(iconnect));
1245 
1246 	s = dup(client->fd);
1247 	if (s == -1)
1248 		return got_error_from_errno("dup");
1249 
1250 	iconnect.client_id = client->id;
1251 	iconnect.euid = client->euid;
1252 	iconnect.egid = client->egid;
1253 
1254 	if (gotd_imsg_compose_event(&client->session->iev, GOTD_IMSG_CONNECT,
1255 	    PROC_GOTD, s, &iconnect, sizeof(iconnect)) == -1) {
1256 		err = got_error_from_errno("imsg compose CONNECT");
1257 		close(s);
1258 		return err;
1259 	}
1260 
1261 	/*
1262 	 * We are no longer interested in messages from this client.
1263 	 * Further client requests will be handled by the session process.
1264 	 */
1265 	msgbuf_clear(&client->iev.ibuf.w);
1266 	imsg_clear(&client->iev.ibuf);
1267 	event_del(&client->iev.ev);
1268 	client->fd = -1; /* will be closed via copy in client->iev.ibuf.fd */
1269 
1270 	return NULL;
1271 }
1272 
1273 static void
1274 gotd_dispatch_client_session(int fd, short event, void *arg)
1275 {
1276 	struct gotd_imsgev *iev = arg;
1277 	struct imsgbuf *ibuf = &iev->ibuf;
1278 	struct gotd_child_proc *proc = NULL;
1279 	struct gotd_client *client = NULL;
1280 	ssize_t n;
1281 	int shut = 0;
1282 	struct imsg imsg;
1283 
1284 	client = find_client_by_proc_fd(fd);
1285 	if (client == NULL) {
1286 		/* Can happen during process teardown. */
1287 		warnx("cannot find client for fd %d", fd);
1288 		shut = 1;
1289 		goto done;
1290 	}
1291 
1292 	if (event & EV_READ) {
1293 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
1294 			fatal("imsg_read error");
1295 		if (n == 0) {
1296 			/* Connection closed. */
1297 			shut = 1;
1298 			goto done;
1299 		}
1300 	}
1301 
1302 	if (event & EV_WRITE) {
1303 		n = msgbuf_write(&ibuf->w);
1304 		if (n == -1 && errno != EAGAIN)
1305 			fatal("msgbuf_write");
1306 		if (n == 0) {
1307 			/* Connection closed. */
1308 			shut = 1;
1309 			goto done;
1310 		}
1311 	}
1312 
1313 	proc = client->session;
1314 	if (proc == NULL)
1315 		fatalx("cannot find session child process for fd %d", fd);
1316 
1317 	for (;;) {
1318 		const struct got_error *err = NULL;
1319 		uint32_t client_id = 0;
1320 		int do_disconnect = 0, do_start_repo_child = 0;
1321 
1322 		if ((n = imsg_get(ibuf, &imsg)) == -1)
1323 			fatal("%s: imsg_get error", __func__);
1324 		if (n == 0)	/* No more messages. */
1325 			break;
1326 
1327 		switch (imsg.hdr.type) {
1328 		case GOTD_IMSG_ERROR:
1329 			do_disconnect = 1;
1330 			err = gotd_imsg_recv_error(&client_id, &imsg);
1331 			break;
1332 		case GOTD_IMSG_CLIENT_SESSION_READY:
1333 			if (client->state != GOTD_CLIENT_STATE_ACCESS_GRANTED) {
1334 				err = got_error(GOT_ERR_PRIVSEP_MSG);
1335 				break;
1336 			}
1337 			do_start_repo_child = 1;
1338 			break;
1339 		case GOTD_IMSG_DISCONNECT:
1340 			do_disconnect = 1;
1341 			break;
1342 		default:
1343 			log_debug("unexpected imsg %d", imsg.hdr.type);
1344 			break;
1345 		}
1346 
1347 		if (!verify_imsg_src(client, proc, &imsg)) {
1348 			log_debug("dropping imsg type %d from PID %d",
1349 			    imsg.hdr.type, proc->pid);
1350 			imsg_free(&imsg);
1351 			continue;
1352 		}
1353 		if (err)
1354 			log_warnx("uid %d: %s", client->euid, err->msg);
1355 
1356 		if (do_start_repo_child) {
1357 			struct gotd_repo *repo;
1358 			const char *name = client->session->repo_name;
1359 
1360 			repo = gotd_find_repo_by_name(name, &gotd);
1361 			if (repo != NULL) {
1362 				enum gotd_procid proc_type;
1363 
1364 				if (client->required_auth & GOTD_AUTH_WRITE)
1365 					proc_type = PROC_REPO_WRITE;
1366 				else
1367 					proc_type = PROC_REPO_READ;
1368 
1369 				err = start_repo_child(client, proc_type, repo,
1370 				    gotd.argv0, gotd.confpath, gotd.daemonize,
1371 				    gotd.verbosity);
1372 			} else
1373 				err = got_error(GOT_ERR_NOT_GIT_REPO);
1374 
1375 			if (err) {
1376 				log_warnx("uid %d: %s", client->euid, err->msg);
1377 				do_disconnect = 1;
1378 			}
1379 		}
1380 
1381 		if (do_disconnect) {
1382 			if (err)
1383 				disconnect_on_error(client, err);
1384 			else
1385 				disconnect(client);
1386 		}
1387 
1388 		imsg_free(&imsg);
1389 	}
1390 done:
1391 	if (!shut) {
1392 		gotd_imsg_event_add(iev);
1393 	} else {
1394 		/* This pipe is dead. Remove its event handler */
1395 		event_del(&iev->ev);
1396 		disconnect(client);
1397 	}
1398 }
1399 
1400 static void
1401 gotd_dispatch_repo_child(int fd, short event, void *arg)
1402 {
1403 	struct gotd_imsgev *iev = arg;
1404 	struct imsgbuf *ibuf = &iev->ibuf;
1405 	struct gotd_child_proc *proc = NULL;
1406 	struct gotd_client *client;
1407 	ssize_t n;
1408 	int shut = 0;
1409 	struct imsg imsg;
1410 
1411 	client = find_client_by_proc_fd(fd);
1412 	if (client == NULL) {
1413 		/* Can happen during process teardown. */
1414 		warnx("cannot find client for fd %d", fd);
1415 		shut = 1;
1416 		goto done;
1417 	}
1418 
1419 	if (event & EV_READ) {
1420 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
1421 			fatal("imsg_read error");
1422 		if (n == 0) {
1423 			/* Connection closed. */
1424 			shut = 1;
1425 			goto done;
1426 		}
1427 	}
1428 
1429 	if (event & EV_WRITE) {
1430 		n = msgbuf_write(&ibuf->w);
1431 		if (n == -1 && errno != EAGAIN)
1432 			fatal("msgbuf_write");
1433 		if (n == 0) {
1434 			/* Connection closed. */
1435 			shut = 1;
1436 			goto done;
1437 		}
1438 	}
1439 
1440 	proc = client->repo;
1441 	if (proc == NULL)
1442 		fatalx("cannot find child process for fd %d", fd);
1443 
1444 	for (;;) {
1445 		const struct got_error *err = NULL;
1446 		uint32_t client_id = 0;
1447 		int do_disconnect = 0;
1448 
1449 		if ((n = imsg_get(ibuf, &imsg)) == -1)
1450 			fatal("%s: imsg_get error", __func__);
1451 		if (n == 0)	/* No more messages. */
1452 			break;
1453 
1454 		switch (imsg.hdr.type) {
1455 		case GOTD_IMSG_ERROR:
1456 			do_disconnect = 1;
1457 			err = gotd_imsg_recv_error(&client_id, &imsg);
1458 			break;
1459 		case GOTD_IMSG_REPO_CHILD_READY:
1460 			err = connect_session(client);
1461 			if (err)
1462 				break;
1463 			err = connect_repo_child(client, proc);
1464 			break;
1465 		default:
1466 			log_debug("unexpected imsg %d", imsg.hdr.type);
1467 			break;
1468 		}
1469 
1470 		if (!verify_imsg_src(client, proc, &imsg)) {
1471 			log_debug("dropping imsg type %d from PID %d",
1472 			    imsg.hdr.type, proc->pid);
1473 			imsg_free(&imsg);
1474 			continue;
1475 		}
1476 		if (err)
1477 			log_warnx("uid %d: %s", client->euid, err->msg);
1478 
1479 		if (do_disconnect) {
1480 			if (err)
1481 				disconnect_on_error(client, err);
1482 			else
1483 				disconnect(client);
1484 		}
1485 
1486 		imsg_free(&imsg);
1487 	}
1488 done:
1489 	if (!shut) {
1490 		gotd_imsg_event_add(iev);
1491 	} else {
1492 		/* This pipe is dead. Remove its event handler */
1493 		event_del(&iev->ev);
1494 		disconnect(client);
1495 	}
1496 }
1497 
1498 static pid_t
1499 start_child(enum gotd_procid proc_id, const char *repo_path,
1500     char *argv0, const char *confpath, int fd, int daemonize, int verbosity)
1501 {
1502 	char	*argv[11];
1503 	int	 argc = 0;
1504 	pid_t	 pid;
1505 
1506 	switch (pid = fork()) {
1507 	case -1:
1508 		fatal("cannot fork");
1509 	case 0:
1510 		break;
1511 	default:
1512 		close(fd);
1513 		return pid;
1514 	}
1515 
1516 	if (fd != GOTD_FILENO_MSG_PIPE) {
1517 		if (dup2(fd, GOTD_FILENO_MSG_PIPE) == -1)
1518 			fatal("cannot setup imsg fd");
1519 	} else if (fcntl(fd, F_SETFD, 0) == -1)
1520 		fatal("cannot setup imsg fd");
1521 
1522 	argv[argc++] = argv0;
1523 	switch (proc_id) {
1524 	case PROC_LISTEN:
1525 		argv[argc++] = (char *)"-L";
1526 		break;
1527 	case PROC_AUTH:
1528 		argv[argc++] = (char *)"-A";
1529 		break;
1530 	case PROC_SESSION_READ:
1531 		argv[argc++] = (char *)"-s";
1532 		break;
1533 	case PROC_SESSION_WRITE:
1534 		argv[argc++] = (char *)"-S";
1535 		break;
1536 	case PROC_REPO_READ:
1537 		argv[argc++] = (char *)"-R";
1538 		break;
1539 	case PROC_REPO_WRITE:
1540 		argv[argc++] = (char *)"-W";
1541 		break;
1542 	default:
1543 		fatalx("invalid process id %d", proc_id);
1544 	}
1545 
1546 	argv[argc++] = (char *)"-f";
1547 	argv[argc++] = (char *)confpath;
1548 
1549 	if (repo_path) {
1550 		argv[argc++] = (char *)"-P";
1551 		argv[argc++] = (char *)repo_path;
1552 	}
1553 
1554 	if (!daemonize)
1555 		argv[argc++] = (char *)"-d";
1556 	if (verbosity > 0)
1557 		argv[argc++] = (char *)"-v";
1558 	if (verbosity > 1)
1559 		argv[argc++] = (char *)"-v";
1560 	argv[argc++] = NULL;
1561 
1562 	execvp(argv0, argv);
1563 	fatal("execvp");
1564 }
1565 
1566 static void
1567 start_listener(char *argv0, const char *confpath, int daemonize, int verbosity)
1568 {
1569 	struct gotd_child_proc *proc;
1570 	int sock_flags = SOCK_STREAM|SOCK_NONBLOCK;
1571 
1572 #ifdef SOCK_CLOEXEC
1573 	sock_flags |= SOCK_CLOEXEC;
1574 #endif
1575 
1576 	proc = calloc(1, sizeof(*proc));
1577 	if (proc == NULL)
1578 		fatal("calloc");
1579 
1580 	TAILQ_INSERT_HEAD(&procs, proc, entry);
1581 
1582 	/* proc->tmo is initialized in main() after event_init() */
1583 
1584 	proc->type = PROC_LISTEN;
1585 
1586 	if (socketpair(AF_UNIX, sock_flags,
1587 	    PF_UNSPEC, proc->pipe) == -1)
1588 		fatal("socketpair");
1589 
1590 	proc->pid = start_child(proc->type, NULL, argv0, confpath,
1591 	    proc->pipe[1], daemonize, verbosity);
1592 	imsg_init(&proc->iev.ibuf, proc->pipe[0]);
1593 	proc->iev.handler = gotd_dispatch_listener;
1594 	proc->iev.events = EV_READ;
1595 	proc->iev.handler_arg = NULL;
1596 
1597 	gotd.listen_proc = proc;
1598 }
1599 
1600 static const struct got_error *
1601 start_session_child(struct gotd_client *client, struct gotd_repo *repo,
1602     char *argv0, const char *confpath, int daemonize, int verbosity)
1603 {
1604 	struct gotd_child_proc *proc;
1605 	int sock_flags = SOCK_STREAM | SOCK_NONBLOCK;
1606 
1607 #ifdef SOCK_CLOEXEC
1608 	sock_flags |= SOCK_CLOEXEC;
1609 #endif
1610 
1611 	proc = calloc(1, sizeof(*proc));
1612 	if (proc == NULL)
1613 		return got_error_from_errno("calloc");
1614 
1615 	TAILQ_INSERT_HEAD(&procs, proc, entry);
1616 	evtimer_set(&proc->tmo, kill_proc_timeout, proc);
1617 
1618 	if (client_is_reading(client))
1619 		proc->type = PROC_SESSION_READ;
1620 	else
1621 		proc->type = PROC_SESSION_WRITE;
1622 	if (strlcpy(proc->repo_name, repo->name,
1623 	    sizeof(proc->repo_name)) >= sizeof(proc->repo_name))
1624 		fatalx("repository name too long: %s", repo->name);
1625 	log_debug("starting client uid %d session for repository %s",
1626 	    client->euid, repo->name);
1627 	if (strlcpy(proc->repo_path, repo->path, sizeof(proc->repo_path)) >=
1628 	    sizeof(proc->repo_path))
1629 		fatalx("repository path too long: %s", repo->path);
1630 	if (socketpair(AF_UNIX, sock_flags, PF_UNSPEC, proc->pipe) == -1)
1631 		fatal("socketpair");
1632 	proc->pid = start_child(proc->type, proc->repo_path, argv0,
1633 	    confpath, proc->pipe[1], daemonize, verbosity);
1634 	imsg_init(&proc->iev.ibuf, proc->pipe[0]);
1635 	log_debug("proc %s %s is on fd %d",
1636 	    gotd_proc_names[proc->type], proc->repo_path,
1637 	    proc->pipe[0]);
1638 	proc->iev.handler = gotd_dispatch_client_session;
1639 	proc->iev.events = EV_READ;
1640 	proc->iev.handler_arg = NULL;
1641 	event_set(&proc->iev.ev, proc->iev.ibuf.fd, EV_READ,
1642 	    gotd_dispatch_client_session, &proc->iev);
1643 	gotd_imsg_event_add(&proc->iev);
1644 
1645 	client->session = proc;
1646 	return NULL;
1647 }
1648 
1649 static const struct got_error *
1650 start_repo_child(struct gotd_client *client, enum gotd_procid proc_type,
1651     struct gotd_repo *repo, char *argv0, const char *confpath,
1652     int daemonize, int verbosity)
1653 {
1654 	struct gotd_child_proc *proc;
1655 	int sock_flags = SOCK_STREAM|SOCK_NONBLOCK;
1656 
1657 #ifdef SOCK_CLOEXEC
1658 	sock_flags |= SOCK_CLOEXEC;
1659 #endif
1660 
1661 	if (proc_type != PROC_REPO_READ && proc_type != PROC_REPO_WRITE)
1662 		return got_error_msg(GOT_ERR_NOT_IMPL, "bad process type");
1663 
1664 	proc = calloc(1, sizeof(*proc));
1665 	if (proc == NULL)
1666 		return got_error_from_errno("calloc");
1667 
1668 	TAILQ_INSERT_HEAD(&procs, proc, entry);
1669 	evtimer_set(&proc->tmo, kill_proc_timeout, proc);
1670 
1671 	proc->type = proc_type;
1672 	if (strlcpy(proc->repo_name, repo->name,
1673 	    sizeof(proc->repo_name)) >= sizeof(proc->repo_name))
1674 		fatalx("repository name too long: %s", repo->name);
1675 	log_debug("starting %s for repository %s",
1676 	    proc->type == PROC_REPO_READ ? "reader" : "writer", repo->name);
1677 
1678 	if (strlcpy(proc->repo_path, repo->path, sizeof(proc->repo_path)) >=
1679 	    sizeof(proc->repo_path))
1680 		fatalx("repository path too long: %s", repo->path);
1681 	if (realpath(repo->path, proc->repo_path) == NULL)
1682 		fatal("%s", repo->path);
1683 	if (socketpair(AF_UNIX, sock_flags,
1684 	    PF_UNSPEC, proc->pipe) == -1)
1685 		fatal("socketpair");
1686 	proc->pid = start_child(proc->type, proc->repo_path, argv0,
1687 	    confpath, proc->pipe[1], daemonize, verbosity);
1688 	imsg_init(&proc->iev.ibuf, proc->pipe[0]);
1689 	log_debug("proc %s %s is on fd %d",
1690 	    gotd_proc_names[proc->type], proc->repo_path,
1691 	    proc->pipe[0]);
1692 	proc->iev.handler = gotd_dispatch_repo_child;
1693 	proc->iev.events = EV_READ;
1694 	proc->iev.handler_arg = NULL;
1695 	event_set(&proc->iev.ev, proc->iev.ibuf.fd, EV_READ,
1696 	    gotd_dispatch_repo_child, &proc->iev);
1697 	gotd_imsg_event_add(&proc->iev);
1698 
1699 	client->repo = proc;
1700 	return NULL;
1701 }
1702 
1703 static const struct got_error *
1704 start_auth_child(struct gotd_client *client, int required_auth,
1705     struct gotd_repo *repo, char *argv0, const char *confpath,
1706     int daemonize, int verbosity)
1707 {
1708 	const struct got_error *err = NULL;
1709 	struct gotd_child_proc *proc;
1710 	struct gotd_imsg_auth iauth;
1711 	int fd;
1712 	int sock_flags = SOCK_STREAM|SOCK_NONBLOCK;
1713 
1714 #ifdef SOCK_CLOEXEC
1715 	sock_flags |= SOCK_CLOEXEC;
1716 #endif
1717 
1718 	memset(&iauth, 0, sizeof(iauth));
1719 
1720 	fd = dup(client->fd);
1721 	if (fd == -1)
1722 		return got_error_from_errno("dup");
1723 
1724 	proc = calloc(1, sizeof(*proc));
1725 	if (proc == NULL) {
1726 		err = got_error_from_errno("calloc");
1727 		close(fd);
1728 		return err;
1729 	}
1730 
1731 	TAILQ_INSERT_HEAD(&procs, proc, entry);
1732 	evtimer_set(&proc->tmo, kill_proc_timeout, proc);
1733 
1734 	proc->type = PROC_AUTH;
1735 	if (strlcpy(proc->repo_name, repo->name,
1736 	    sizeof(proc->repo_name)) >= sizeof(proc->repo_name))
1737 		fatalx("repository name too long: %s", repo->name);
1738 	log_debug("starting auth for uid %d repository %s",
1739 	    client->euid, repo->name);
1740 	if (strlcpy(proc->repo_path, repo->path, sizeof(proc->repo_path)) >=
1741 	    sizeof(proc->repo_path))
1742 		fatalx("repository path too long: %s", repo->path);
1743 	if (realpath(repo->path, proc->repo_path) == NULL)
1744 		fatal("%s", repo->path);
1745 	if (socketpair(AF_UNIX, sock_flags,
1746 	    PF_UNSPEC, proc->pipe) == -1)
1747 		fatal("socketpair");
1748 	proc->pid = start_child(proc->type, proc->repo_path, argv0,
1749 	    confpath, proc->pipe[1], daemonize, verbosity);
1750 	imsg_init(&proc->iev.ibuf, proc->pipe[0]);
1751 	log_debug("proc %s %s is on fd %d",
1752 	    gotd_proc_names[proc->type], proc->repo_path,
1753 	    proc->pipe[0]);
1754 	proc->iev.handler = gotd_dispatch_auth_child;
1755 	proc->iev.events = EV_READ;
1756 	proc->iev.handler_arg = NULL;
1757 	event_set(&proc->iev.ev, proc->iev.ibuf.fd, EV_READ,
1758 	    gotd_dispatch_auth_child, &proc->iev);
1759 	gotd_imsg_event_add(&proc->iev);
1760 
1761 	iauth.euid = client->euid;
1762 	iauth.egid = client->egid;
1763 	iauth.required_auth = required_auth;
1764 	iauth.client_id = client->id;
1765 	if (gotd_imsg_compose_event(&proc->iev, GOTD_IMSG_AUTHENTICATE,
1766 	    PROC_GOTD, fd, &iauth, sizeof(iauth)) == -1) {
1767 		log_warn("imsg compose AUTHENTICATE");
1768 		close(fd);
1769 		/* Let the auth_timeout handler tidy up. */
1770 	}
1771 
1772 	client->auth = proc;
1773 	client->required_auth = required_auth;
1774 	return NULL;
1775 }
1776 
1777 static void
1778 apply_unveil_repo_readonly(const char *repo_path, int need_tmpdir)
1779 {
1780 	if (need_tmpdir) {
1781 		if (unveil(GOT_TMPDIR_STR, "rwc") == -1)
1782 			fatal("unveil %s", GOT_TMPDIR_STR);
1783 	}
1784 
1785 	if (unveil(repo_path, "r") == -1)
1786 		fatal("unveil %s", repo_path);
1787 
1788 	if (unveil(NULL, NULL) == -1)
1789 		fatal("unveil");
1790 }
1791 
1792 static void
1793 apply_unveil_repo_readwrite(const char *repo_path)
1794 {
1795 	if (unveil(repo_path, "rwc") == -1)
1796 		fatal("unveil %s", repo_path);
1797 
1798 	if (unveil(GOT_TMPDIR_STR, "rwc") == -1)
1799 		fatal("unveil %s", GOT_TMPDIR_STR);
1800 
1801 	if (unveil(NULL, NULL) == -1)
1802 		fatal("unveil");
1803 }
1804 
1805 static void
1806 apply_unveil_none(void)
1807 {
1808 	if (unveil("/", "") == -1)
1809 		fatal("unveil");
1810 
1811 	if (unveil(NULL, NULL) == -1)
1812 		fatal("unveil");
1813 }
1814 
1815 static void
1816 apply_unveil_selfexec(void)
1817 {
1818 	if (unveil(gotd.argv0, "x") == -1)
1819 		fatal("unveil %s", gotd.argv0);
1820 
1821 	if (unveil(NULL, NULL) == -1)
1822 		fatal("unveil");
1823 }
1824 
1825 static void
1826 drop_privs(struct passwd *pw)
1827 {
1828 	/* Drop root privileges. */
1829 	if (setgid(pw->pw_gid) == -1)
1830 		fatal("setgid %d failed", pw->pw_gid);
1831 	if (setuid(pw->pw_uid) == -1)
1832 		fatal("setuid %d failed", pw->pw_uid);
1833 }
1834 
1835 int
1836 main(int argc, char **argv)
1837 {
1838 	const struct got_error *error = NULL;
1839 	int ch, fd = -1, daemonize = 1, verbosity = 0, noaction = 0;
1840 	const char *confpath = GOTD_CONF_PATH;
1841 	char *argv0 = argv[0];
1842 	char title[2048];
1843 	struct passwd *pw = NULL;
1844 	char *repo_path = NULL;
1845 	enum gotd_procid proc_id = PROC_GOTD;
1846 	struct event evsigint, evsigterm, evsighup, evsigusr1, evsigchld;
1847 	int *pack_fds = NULL, *temp_fds = NULL;
1848 	struct gotd_repo *repo = NULL;
1849 
1850 	TAILQ_INIT(&procs);
1851 
1852 	log_init(1, LOG_DAEMON); /* Log to stderr until daemonized. */
1853 
1854 	while ((ch = getopt(argc, argv, "Adf:LnP:RsSvW")) != -1) {
1855 		switch (ch) {
1856 		case 'A':
1857 			proc_id = PROC_AUTH;
1858 			break;
1859 		case 'd':
1860 			daemonize = 0;
1861 			break;
1862 		case 'f':
1863 			confpath = optarg;
1864 			break;
1865 		case 'L':
1866 			proc_id = PROC_LISTEN;
1867 			break;
1868 		case 'n':
1869 			noaction = 1;
1870 			break;
1871 		case 'P':
1872 			repo_path = realpath(optarg, NULL);
1873 			if (repo_path == NULL)
1874 				fatal("realpath '%s'", optarg);
1875 			break;
1876 		case 'R':
1877 			proc_id = PROC_REPO_READ;
1878 			break;
1879 		case 's':
1880 			proc_id = PROC_SESSION_READ;
1881 			break;
1882 		case 'S':
1883 			proc_id = PROC_SESSION_WRITE;
1884 			break;
1885 		case 'v':
1886 			if (verbosity < 3)
1887 				verbosity++;
1888 			break;
1889 		case 'W':
1890 			proc_id = PROC_REPO_WRITE;
1891 			break;
1892 		default:
1893 			usage();
1894 		}
1895 	}
1896 
1897 	argc -= optind;
1898 	argv += optind;
1899 
1900 	if (argc != 0)
1901 		usage();
1902 
1903 	if (geteuid() && (proc_id == PROC_GOTD || proc_id == PROC_LISTEN))
1904 		fatalx("need root privileges");
1905 
1906 	if (parse_config(confpath, proc_id, &gotd) != 0)
1907 		return 1;
1908 
1909 	pw = getpwnam(gotd.user_name);
1910 	if (pw == NULL)
1911 		fatalx("user %s not found", gotd.user_name);
1912 
1913 	if (pw->pw_uid == 0)
1914 		fatalx("cannot run %s as the superuser", getprogname());
1915 
1916 	if (noaction) {
1917 		fprintf(stderr, "configuration OK\n");
1918 		return 0;
1919 	}
1920 
1921 	gotd.argv0 = argv0;
1922 	gotd.daemonize = daemonize;
1923 	gotd.verbosity = verbosity;
1924 	gotd.confpath = confpath;
1925 
1926 	/* Require an absolute path in argv[0] for reliable re-exec. */
1927 	if (!got_path_is_absolute(argv0))
1928 		fatalx("bad path \"%s\": must be an absolute path", argv0);
1929 
1930 	log_init(daemonize ? 0 : 1, LOG_DAEMON);
1931 	log_setverbose(verbosity);
1932 
1933 	if (proc_id == PROC_GOTD) {
1934 		snprintf(title, sizeof(title), "%s", gotd_proc_names[proc_id]);
1935 		arc4random_buf(&clients_hash_key, sizeof(clients_hash_key));
1936 		if (daemonize && daemon(1, 0) == -1)
1937 			fatal("daemon");
1938 		gotd.pid = getpid();
1939 		start_listener(argv0, confpath, daemonize, verbosity);
1940 	} else if (proc_id == PROC_LISTEN) {
1941 		snprintf(title, sizeof(title), "%s", gotd_proc_names[proc_id]);
1942 		if (verbosity) {
1943 			log_info("socket: %s", gotd.unix_socket_path);
1944 			log_info("user: %s", pw->pw_name);
1945 		}
1946 
1947 		fd = unix_socket_listen(gotd.unix_socket_path, pw->pw_uid,
1948 		    pw->pw_gid);
1949 		if (fd == -1) {
1950 			fatal("cannot listen on unix socket %s",
1951 			    gotd.unix_socket_path);
1952 		}
1953 	} else if (proc_id == PROC_AUTH) {
1954 		snprintf(title, sizeof(title), "%s %s",
1955 		    gotd_proc_names[proc_id], repo_path);
1956 	} else if (proc_id == PROC_REPO_READ || proc_id == PROC_REPO_WRITE ||
1957 	    proc_id == PROC_SESSION_READ || proc_id == PROC_SESSION_WRITE) {
1958 		error = got_repo_pack_fds_open(&pack_fds);
1959 		if (error != NULL)
1960 			fatalx("cannot open pack tempfiles: %s", error->msg);
1961 		error = got_repo_temp_fds_open(&temp_fds);
1962 		if (error != NULL)
1963 			fatalx("cannot open pack tempfiles: %s", error->msg);
1964 		if (repo_path == NULL)
1965 			fatalx("repository path not specified");
1966 		snprintf(title, sizeof(title), "%s %s",
1967 		    gotd_proc_names[proc_id], repo_path);
1968 	} else
1969 		fatal("invalid process id %d", proc_id);
1970 
1971 	setproctitle("%s", title);
1972 	log_procinit(title);
1973 
1974 	if (proc_id != PROC_GOTD && proc_id != PROC_LISTEN &&
1975 	    proc_id != PROC_REPO_READ && proc_id != PROC_REPO_WRITE) {
1976 		/* Drop root privileges. */
1977 		if (setgid(pw->pw_gid) == -1)
1978 			fatal("setgid %d failed", pw->pw_gid);
1979 		if (setuid(pw->pw_uid) == -1)
1980 			fatal("setuid %d failed", pw->pw_uid);
1981 	}
1982 
1983 	event_init();
1984 
1985 	switch (proc_id) {
1986 	case PROC_GOTD:
1987 #ifndef PROFILE
1988 		/* "exec" promise will be limited to argv[0] via unveil(2). */
1989 		if (pledge("stdio proc exec sendfd recvfd unveil", NULL) == -1)
1990 			err(1, "pledge");
1991 #endif
1992 		break;
1993 	case PROC_LISTEN:
1994 #ifndef PROFILE
1995 		if (pledge("stdio sendfd unix unveil", NULL) == -1)
1996 			err(1, "pledge");
1997 #endif
1998 		/*
1999 		 * Ensure that AF_UNIX bind(2) cannot be used with any other
2000 		 * sockets by revoking all filesystem access via unveil(2).
2001 		 */
2002 		apply_unveil_none();
2003 
2004 		enter_chroot(GOTD_EMPTY_PATH);
2005 		drop_privs(pw);
2006 
2007 		listen_main(title, fd, gotd.connection_limits,
2008 		    gotd.nconnection_limits);
2009 		/* NOTREACHED */
2010 		break;
2011 	case PROC_AUTH:
2012 #ifndef PROFILE
2013 		if (pledge("stdio getpw recvfd unix unveil", NULL) == -1)
2014 			err(1, "pledge");
2015 #endif
2016 		/*
2017 		 * We need the "unix" pledge promise for getpeername(2) only.
2018 		 * Ensure that AF_UNIX bind(2) cannot be used by revoking all
2019 		 * filesystem access via unveil(2). Access to password database
2020 		 * files will still work since "getpw" bypasses unveil(2).
2021 		 */
2022 		apply_unveil_none();
2023 
2024 		auth_main(title, &gotd.repos, repo_path);
2025 		/* NOTREACHED */
2026 		break;
2027 	case PROC_SESSION_READ:
2028 	case PROC_SESSION_WRITE:
2029 #ifndef PROFILE
2030 		/*
2031 		 * The "recvfd" promise is only needed during setup and
2032 		 * will be removed in a later pledge(2) call.
2033 		 */
2034 		if (pledge("stdio rpath wpath cpath recvfd sendfd fattr flock "
2035 		    "unveil", NULL) == -1)
2036 			err(1, "pledge");
2037 #endif
2038 		if (proc_id == PROC_SESSION_READ)
2039 			apply_unveil_repo_readonly(repo_path, 1);
2040 		else
2041 			apply_unveil_repo_readwrite(repo_path);
2042 
2043 		session_main(title, repo_path, pack_fds, temp_fds,
2044 		    &gotd.request_timeout, proc_id);
2045 		/* NOTREACHED */
2046 		break;
2047 	case PROC_REPO_READ:
2048 #ifndef PROFILE
2049 		if (pledge("stdio rpath recvfd unveil", NULL) == -1)
2050 			err(1, "pledge");
2051 #endif
2052 		apply_unveil_repo_readonly(repo_path, 0);
2053 
2054 		if (enter_chroot(repo_path)) {
2055 			log_info("change repo path %s", repo_path);
2056 			free(repo_path);
2057 			repo_path = strdup("/");
2058 			if (repo_path == NULL)
2059 				fatal("strdup");
2060 			log_info("repo path is now %s", repo_path);
2061 		}
2062 		drop_privs(pw);
2063 
2064 		repo_read_main(title, repo_path, pack_fds, temp_fds);
2065 		/* NOTREACHED */
2066 		exit(0);
2067 	case PROC_REPO_WRITE:
2068 #ifndef PROFILE
2069 		if (pledge("stdio rpath recvfd unveil", NULL) == -1)
2070 			err(1, "pledge");
2071 #endif
2072 		apply_unveil_repo_readonly(repo_path, 0);
2073 		repo = gotd_find_repo_by_path(repo_path, &gotd);
2074 		if (repo == NULL)
2075 			fatalx("no repository for path %s", repo_path);
2076 
2077 		if (enter_chroot(repo_path)) {
2078 			free(repo_path);
2079 			repo_path = strdup("/");
2080 			if (repo_path == NULL)
2081 				fatal("strdup");
2082 		}
2083 		drop_privs(pw);
2084 
2085 		repo_write_main(title, repo_path, pack_fds, temp_fds,
2086 		    &repo->protected_tag_namespaces,
2087 		    &repo->protected_branch_namespaces,
2088 		    &repo->protected_branches);
2089 		/* NOTREACHED */
2090 		exit(0);
2091 	default:
2092 		fatal("invalid process id %d", proc_id);
2093 	}
2094 
2095 	if (proc_id != PROC_GOTD)
2096 		fatal("invalid process id %d", proc_id);
2097 
2098 	evtimer_set(&gotd.listen_proc->tmo, kill_proc_timeout,
2099 	    gotd.listen_proc);
2100 
2101 	apply_unveil_selfexec();
2102 
2103 	signal_set(&evsigint, SIGINT, gotd_sighdlr, NULL);
2104 	signal_set(&evsigterm, SIGTERM, gotd_sighdlr, NULL);
2105 	signal_set(&evsighup, SIGHUP, gotd_sighdlr, NULL);
2106 	signal_set(&evsigusr1, SIGUSR1, gotd_sighdlr, NULL);
2107 	signal_set(&evsigchld, SIGCHLD, gotd_sighdlr, NULL);
2108 	signal(SIGPIPE, SIG_IGN);
2109 
2110 	signal_add(&evsigint, NULL);
2111 	signal_add(&evsigterm, NULL);
2112 	signal_add(&evsighup, NULL);
2113 	signal_add(&evsigusr1, NULL);
2114 	signal_add(&evsigchld, NULL);
2115 
2116 	gotd_imsg_event_add(&gotd.listen_proc->iev);
2117 
2118 	event_dispatch();
2119 
2120 	free(repo_path);
2121 	gotd_shutdown();
2122 
2123 	return 0;
2124 }