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 <sys/queue.h>
18 #include <sys/tree.h>
19 #include <sys/time.h>
20 #include <sys/types.h>
21 #include <sys/stat.h>
22 #include <sys/socket.h>
23 #include <sys/un.h>
24 #include <sys/wait.h>
25 #include <sys/resource.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 <sha1.h>
35 #include <sha2.h>
36 #include <signal.h>
37 #include <siphash.h>
38 #include <stdarg.h>
39 #include <stdio.h>
40 #include <stdlib.h>
41 #include <string.h>
42 #include <syslog.h>
43 #include <unistd.h>
44 
45 #include "got_error.h"
46 #include "got_opentemp.h"
47 #include "got_path.h"
48 #include "got_repository.h"
49 #include "got_object.h"
50 #include "got_reference.h"
51 #include "got_diff.h"
52 
53 #include "got_lib_delta.h"
54 #include "got_lib_object.h"
55 #include "got_lib_object_cache.h"
56 #include "got_lib_hash.h"
57 #include "got_lib_gitproto.h"
58 #include "got_lib_pack.h"
59 #include "got_lib_repository.h"
60 
61 #include "gotd.h"
62 #include "log.h"
63 #include "listen.h"
64 #include "auth.h"
65 #include "session.h"
66 #include "repo_read.h"
67 #include "repo_write.h"
68 #include "notify.h"
69 
70 #ifndef nitems
71 #define nitems(_a)	(sizeof((_a)) / sizeof((_a)[0]))
72 #endif
73 
74 enum gotd_client_state {
75 	GOTD_CLIENT_STATE_NEW,
76 	GOTD_CLIENT_STATE_ACCESS_GRANTED,
77 };
78 
79 struct gotd_child_proc {
80 	pid_t				 pid;
81 	enum gotd_procid		 type;
82 	char				 repo_name[NAME_MAX];
83 	char				 repo_path[PATH_MAX];
84 	int				 pipe[2];
85 	struct gotd_imsgev		 iev;
86 	struct event			 tmo;
87 
88 	TAILQ_ENTRY(gotd_child_proc)	 entry;
89 };
90 TAILQ_HEAD(gotd_procs, gotd_child_proc) procs;
91 
92 struct gotd_client {
93 	STAILQ_ENTRY(gotd_client)	 entry;
94 	enum gotd_client_state		 state;
95 	uint32_t			 id;
96 	int				 fd;
97 	struct gotd_imsgev		 iev;
98 	struct event			 tmo;
99 	uid_t				 euid;
100 	gid_t				 egid;
101 	char				*username;
102 	struct gotd_child_proc		*repo;
103 	struct gotd_child_proc		*auth;
104 	struct gotd_child_proc		*session;
105 	int				 required_auth;
106 };
107 STAILQ_HEAD(gotd_clients, gotd_client);
108 
109 static struct gotd_clients gotd_clients[GOTD_CLIENT_TABLE_SIZE];
110 static SIPHASH_KEY clients_hash_key;
111 volatile int client_cnt;
112 static struct timeval auth_timeout = { 5, 0 };
113 static struct gotd gotd;
114 
115 void gotd_sighdlr(int sig, short event, void *arg);
116 static void gotd_shutdown(void);
117 static const struct got_error *start_session_child(struct gotd_client *,
118     struct gotd_repo *, char *, const char *, int, int);
119 static const struct got_error *start_repo_child(struct gotd_client *,
120     enum gotd_procid, struct gotd_repo *, char *, const char *, int, int);
121 static const struct got_error *start_auth_child(struct gotd_client *, int,
122     struct gotd_repo *, char *, const char *, int, int);
123 static void kill_proc(struct gotd_child_proc *, int);
124 static void disconnect(struct gotd_client *);
125 
126 __dead static void
127 usage(void)
128 {
129 	fprintf(stderr, "usage: %s [-dnv] [-f config-file]\n", getprogname());
130 	exit(1);
131 }
132 
133 static int
134 unix_socket_listen(const char *unix_socket_path, uid_t uid, gid_t gid)
135 {
136 	struct sockaddr_un sun;
137 	int fd = -1;
138 	mode_t old_umask, mode;
139 
140 	fd = socket(AF_UNIX, SOCK_STREAM | SOCK_NONBLOCK| SOCK_CLOEXEC, 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 	if (proc == gotd.notify_proc)
306 		gotd.notify_proc = NULL;
307 
308 	evtimer_del(&proc->tmo);
309 
310 	if (proc->iev.ibuf.fd != -1) {
311 		event_del(&proc->iev.ev);
312 		msgbuf_clear(&proc->iev.ibuf.w);
313 		close(proc->iev.ibuf.fd);
314 	}
315 
316 	free(proc);
317 }
318 
319 static void
320 kill_repo_proc(struct gotd_client *client)
321 {
322 	if (client->repo == NULL)
323 		return;
324 
325 	kill_proc(client->repo, 0);
326 	client->repo = NULL;
327 }
328 
329 static void
330 kill_auth_proc(struct gotd_client *client)
331 {
332 	if (client->auth == NULL)
333 		return;
334 
335 	kill_proc(client->auth, 0);
336 	client->auth = NULL;
337 }
338 
339 static void
340 kill_session_proc(struct gotd_client *client)
341 {
342 	if (client->session == NULL)
343 		return;
344 
345 	kill_proc(client->session, 0);
346 	client->session = NULL;
347 }
348 
349 static void
350 disconnect(struct gotd_client *client)
351 {
352 	struct gotd_imsg_disconnect idisconnect;
353 	struct gotd_child_proc *listen_proc = gotd.listen_proc;
354 	uint64_t slot;
355 
356 	log_debug("uid %d: disconnecting", client->euid);
357 
358 	kill_auth_proc(client);
359 	kill_session_proc(client);
360 	kill_repo_proc(client);
361 
362 	idisconnect.client_id = client->id;
363 	if (gotd_imsg_compose_event(&listen_proc->iev,
364 	    GOTD_IMSG_DISCONNECT, PROC_GOTD, -1,
365 	    &idisconnect, sizeof(idisconnect)) == -1)
366 		log_warn("imsg compose DISCONNECT");
367 
368 	slot = client_hash(client->id) % nitems(gotd_clients);
369 	STAILQ_REMOVE(&gotd_clients[slot], client, gotd_client, entry);
370 	imsg_clear(&client->iev.ibuf);
371 	event_del(&client->iev.ev);
372 	evtimer_del(&client->tmo);
373 	if (client->fd != -1)
374 		close(client->fd);
375 	else if (client->iev.ibuf.fd != -1)
376 		close(client->iev.ibuf.fd);
377 	free(client->username);
378 	free(client);
379 	client_cnt--;
380 }
381 
382 static void
383 disconnect_on_error(struct gotd_client *client, const struct got_error *err)
384 {
385 	struct imsgbuf ibuf;
386 
387 	if (err->code != GOT_ERR_EOF) {
388 		log_warnx("uid %d: %s", client->euid, err->msg);
389 		if (client->fd != -1) {
390 			imsg_init(&ibuf, client->fd);
391 			gotd_imsg_send_error(&ibuf, 0, PROC_GOTD, err);
392 			imsg_clear(&ibuf);
393 		}
394 	}
395 	disconnect(client);
396 }
397 
398 static const struct got_error *
399 send_repo_info(struct gotd_imsgev *iev, struct gotd_repo *repo)
400 {
401 	const struct got_error *err = NULL;
402 	struct gotd_imsg_info_repo irepo;
403 
404 	memset(&irepo, 0, sizeof(irepo));
405 
406 	if (strlcpy(irepo.repo_name, repo->name, sizeof(irepo.repo_name))
407 	    >= sizeof(irepo.repo_name))
408 		return got_error_msg(GOT_ERR_NO_SPACE, "repo name too long");
409 	if (strlcpy(irepo.repo_path, repo->path, sizeof(irepo.repo_path))
410 	    >= sizeof(irepo.repo_path))
411 		return got_error_msg(GOT_ERR_NO_SPACE, "repo path too long");
412 
413 	if (gotd_imsg_compose_event(iev, GOTD_IMSG_INFO_REPO, PROC_GOTD, -1,
414 	    &irepo, sizeof(irepo)) == -1) {
415 		err = got_error_from_errno("imsg compose INFO_REPO");
416 		if (err)
417 			return err;
418 	}
419 
420 	return NULL;
421 }
422 
423 static const struct got_error *
424 send_client_info(struct gotd_imsgev *iev, struct gotd_client *client)
425 {
426 	const struct got_error *err = NULL;
427 	struct gotd_imsg_info_client iclient;
428 	struct gotd_child_proc *proc;
429 
430 	memset(&iclient, 0, sizeof(iclient));
431 	iclient.euid = client->euid;
432 	iclient.egid = client->egid;
433 
434 	proc = client->repo;
435 	if (proc) {
436 		if (strlcpy(iclient.repo_name, proc->repo_path,
437 		    sizeof(iclient.repo_name)) >= sizeof(iclient.repo_name)) {
438 			return got_error_msg(GOT_ERR_NO_SPACE,
439 			    "repo name too long");
440 		}
441 		if (client_is_writing(client))
442 			iclient.is_writing = 1;
443 
444 		iclient.repo_child_pid = proc->pid;
445 	}
446 
447 	if (client->session)
448 		iclient.session_child_pid = client->session->pid;
449 
450 	if (gotd_imsg_compose_event(iev, GOTD_IMSG_INFO_CLIENT, PROC_GOTD, -1,
451 	    &iclient, sizeof(iclient)) == -1) {
452 		err = got_error_from_errno("imsg compose INFO_CLIENT");
453 		if (err)
454 			return err;
455 	}
456 
457 	return NULL;
458 }
459 
460 static const struct got_error *
461 send_info(struct gotd_client *client)
462 {
463 	const struct got_error *err = NULL;
464 	struct gotd_imsg_info info;
465 	uint64_t slot;
466 	struct gotd_repo *repo;
467 
468 	if (client->euid != 0)
469 		return got_error_set_errno(EPERM, "info");
470 
471 	info.pid = gotd.pid;
472 	info.verbosity = gotd.verbosity;
473 	info.nrepos = gotd.nrepos;
474 	info.nclients = client_cnt - 1;
475 
476 	if (gotd_imsg_compose_event(&client->iev, GOTD_IMSG_INFO, PROC_GOTD, -1,
477 	    &info, sizeof(info)) == -1) {
478 		err = got_error_from_errno("imsg compose INFO");
479 		if (err)
480 			return err;
481 	}
482 
483 	TAILQ_FOREACH(repo, &gotd.repos, entry) {
484 		err = send_repo_info(&client->iev, repo);
485 		if (err)
486 			return err;
487 	}
488 
489 	for (slot = 0; slot < nitems(gotd_clients); slot++) {
490 		struct gotd_client *c;
491 		STAILQ_FOREACH(c, &gotd_clients[slot], entry) {
492 			if (c->id == client->id)
493 				continue;
494 			err = send_client_info(&client->iev, c);
495 			if (err)
496 				return err;
497 		}
498 	}
499 
500 	return NULL;
501 }
502 
503 static const struct got_error *
504 stop_gotd(struct gotd_client *client)
505 {
506 
507 	if (client->euid != 0)
508 		return got_error_set_errno(EPERM, "stop");
509 
510 	gotd_shutdown();
511 	/* NOTREACHED */
512 	return NULL;
513 }
514 
515 static const struct got_error *
516 start_client_authentication(struct gotd_client *client, struct imsg *imsg)
517 {
518 	const struct got_error *err;
519 	struct gotd_imsg_list_refs ireq;
520 	struct gotd_repo *repo = NULL;
521 	size_t datalen;
522 
523 	log_debug("list-refs request from uid %d", client->euid);
524 
525 	if (client->state != GOTD_CLIENT_STATE_NEW)
526 		return got_error_msg(GOT_ERR_BAD_REQUEST,
527 		    "unexpected list-refs request received");
528 
529 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
530 	if (datalen != sizeof(ireq))
531 		return got_error(GOT_ERR_PRIVSEP_LEN);
532 
533 	memcpy(&ireq, imsg->data, datalen);
534 
535 	if (ireq.client_is_reading) {
536 		err = ensure_client_is_not_writing(client);
537 		if (err)
538 			return err;
539 		repo = gotd_find_repo_by_name(ireq.repo_name, &gotd.repos);
540 		if (repo == NULL)
541 			return got_error(GOT_ERR_NOT_GIT_REPO);
542 		err = start_auth_child(client, GOTD_AUTH_READ, repo,
543 		    gotd.argv0, gotd.confpath, gotd.daemonize,
544 		    gotd.verbosity);
545 		if (err)
546 			return err;
547 	} else {
548 		err = ensure_client_is_not_reading(client);
549 		if (err)
550 			return err;
551 		repo = gotd_find_repo_by_name(ireq.repo_name, &gotd.repos);
552 		if (repo == NULL)
553 			return got_error(GOT_ERR_NOT_GIT_REPO);
554 		err = start_auth_child(client,
555 		    GOTD_AUTH_READ | GOTD_AUTH_WRITE,
556 		    repo, gotd.argv0, gotd.confpath, gotd.daemonize,
557 		    gotd.verbosity);
558 		if (err)
559 			return err;
560 	}
561 
562 	evtimer_add(&client->tmo, &auth_timeout);
563 
564 	/* Flow continues upon authentication success/failure or timeout. */
565 	return NULL;
566 }
567 
568 static void
569 gotd_request(int fd, short events, void *arg)
570 {
571 	struct gotd_imsgev *iev = arg;
572 	struct imsgbuf *ibuf = &iev->ibuf;
573 	struct gotd_client *client = iev->handler_arg;
574 	const struct got_error *err = NULL;
575 	struct imsg imsg;
576 	ssize_t n;
577 
578 	if (events & EV_WRITE) {
579 		while (ibuf->w.queued) {
580 			n = msgbuf_write(&ibuf->w);
581 			if (n == -1 && errno == EPIPE) {
582 				/*
583 				 * The client has closed its socket.
584 				 * This can happen when Git clients are
585 				 * done sending pack file data.
586 				 */
587 				msgbuf_clear(&ibuf->w);
588 				continue;
589 			} else if (n == -1 && errno != EAGAIN) {
590 				err = got_error_from_errno("imsg_flush");
591 				disconnect_on_error(client, err);
592 				return;
593 			}
594 			if (n == 0) {
595 				/* Connection closed. */
596 				err = got_error(GOT_ERR_EOF);
597 				disconnect_on_error(client, err);
598 				return;
599 			}
600 		}
601 
602 		/* Disconnect gotctl(8) now that messages have been sent. */
603 		if (!client_is_reading(client) && !client_is_writing(client)) {
604 			disconnect(client);
605 			return;
606 		}
607 	}
608 
609 	if ((events & EV_READ) == 0)
610 		return;
611 
612 	memset(&imsg, 0, sizeof(imsg));
613 
614 	while (err == NULL) {
615 		err = gotd_imsg_recv(&imsg, ibuf, 0);
616 		if (err) {
617 			if (err->code == GOT_ERR_PRIVSEP_READ)
618 				err = NULL;
619 			break;
620 		}
621 
622 		evtimer_del(&client->tmo);
623 
624 		switch (imsg.hdr.type) {
625 		case GOTD_IMSG_INFO:
626 			err = send_info(client);
627 			break;
628 		case GOTD_IMSG_STOP:
629 			err = stop_gotd(client);
630 			break;
631 		case GOTD_IMSG_LIST_REFS:
632 			err = start_client_authentication(client, &imsg);
633 			break;
634 		default:
635 			log_debug("unexpected imsg %d", imsg.hdr.type);
636 			err = got_error(GOT_ERR_PRIVSEP_MSG);
637 			break;
638 		}
639 
640 		imsg_free(&imsg);
641 	}
642 
643 	if (err) {
644 		disconnect_on_error(client, err);
645 	} else {
646 		gotd_imsg_event_add(&client->iev);
647 	}
648 }
649 
650 static void
651 gotd_auth_timeout(int fd, short events, void *arg)
652 {
653 	struct gotd_client *client = arg;
654 
655 	log_debug("disconnecting uid %d due to authentication timeout",
656 	    client->euid);
657 	disconnect(client);
658 }
659 
660 static const struct got_error *
661 recv_connect(uint32_t *client_id, struct imsg *imsg)
662 {
663 	const struct got_error *err = NULL;
664 	struct gotd_imsg_connect iconnect;
665 	size_t datalen;
666 	int s = -1;
667 	struct gotd_client *client = NULL;
668 
669 	*client_id = 0;
670 
671 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
672 	if (datalen != sizeof(iconnect))
673 		return got_error(GOT_ERR_PRIVSEP_LEN);
674 	memcpy(&iconnect, imsg->data, sizeof(iconnect));
675 
676 	s = imsg_get_fd(imsg);
677 	if (s == -1) {
678 		err = got_error(GOT_ERR_PRIVSEP_NO_FD);
679 		goto done;
680 	}
681 
682 	if (find_client(iconnect.client_id)) {
683 		err = got_error_msg(GOT_ERR_CLIENT_ID, "duplicate client ID");
684 		goto done;
685 	}
686 
687 	client = calloc(1, sizeof(*client));
688 	if (client == NULL) {
689 		err = got_error_from_errno("calloc");
690 		goto done;
691 	}
692 
693 	*client_id = iconnect.client_id;
694 
695 	client->state = GOTD_CLIENT_STATE_NEW;
696 	client->id = iconnect.client_id;
697 	client->fd = s;
698 	s = -1;
699 	/* The auth process will verify UID/GID for us. */
700 	client->euid = iconnect.euid;
701 	client->egid = iconnect.egid;
702 
703 	imsg_init(&client->iev.ibuf, client->fd);
704 	client->iev.handler = gotd_request;
705 	client->iev.events = EV_READ;
706 	client->iev.handler_arg = client;
707 
708 	event_set(&client->iev.ev, client->fd, EV_READ, gotd_request,
709 	    &client->iev);
710 	gotd_imsg_event_add(&client->iev);
711 
712 	evtimer_set(&client->tmo, gotd_auth_timeout, client);
713 
714 	add_client(client);
715 	log_debug("%s: new client uid %d connected on fd %d", __func__,
716 	    client->euid, client->fd);
717 done:
718 	if (err) {
719 		struct gotd_child_proc *listen_proc = gotd.listen_proc;
720 		struct gotd_imsg_disconnect idisconnect;
721 
722 		idisconnect.client_id = client->id;
723 		if (gotd_imsg_compose_event(&listen_proc->iev,
724 		    GOTD_IMSG_DISCONNECT, PROC_GOTD, -1,
725 		    &idisconnect, sizeof(idisconnect)) == -1)
726 			log_warn("imsg compose DISCONNECT");
727 
728 		if (s != -1)
729 			close(s);
730 	}
731 
732 	return err;
733 }
734 
735 static const char *gotd_proc_names[PROC_MAX] = {
736 	"parent",
737 	"listen",
738 	"auth",
739 	"session_read",
740 	"session_write",
741 	"repo_read",
742 	"repo_write",
743 	"gitwrapper",
744 	"notify"
745 };
746 
747 static void
748 kill_proc(struct gotd_child_proc *proc, int fatal)
749 {
750 	struct timeval tv = { 5, 0 };
751 
752 	log_debug("kill -%d %d", fatal ? SIGKILL : SIGTERM, proc->pid);
753 
754 	if (proc->iev.ibuf.fd != -1) {
755 		event_del(&proc->iev.ev);
756 		msgbuf_clear(&proc->iev.ibuf.w);
757 		close(proc->iev.ibuf.fd);
758 		proc->iev.ibuf.fd = -1;
759 	}
760 
761 	if (!evtimer_pending(&proc->tmo, NULL) && !fatal)
762 		evtimer_add(&proc->tmo, &tv);
763 
764 	if (fatal) {
765 		log_warnx("sending SIGKILL to PID %d", proc->pid);
766 		kill(proc->pid, SIGKILL);
767 	} else
768 		kill(proc->pid, SIGTERM);
769 }
770 
771 static void
772 kill_proc_timeout(int fd, short ev, void *d)
773 {
774 	struct gotd_child_proc *proc = d;
775 
776 	log_warnx("timeout waiting for PID %d to terminate;"
777 	    " retrying with force", proc->pid);
778 	kill_proc(proc, 1);
779 }
780 
781 static void
782 gotd_shutdown(void)
783 {
784 	uint64_t slot;
785 
786 	log_debug("shutting down");
787 	for (slot = 0; slot < nitems(gotd_clients); slot++) {
788 		struct gotd_client *c, *tmp;
789 
790 		STAILQ_FOREACH_SAFE(c, &gotd_clients[slot], entry, tmp)
791 			disconnect(c);
792 	}
793 
794 	kill_proc(gotd.listen_proc, 0);
795 
796 	log_info("terminating");
797 	exit(0);
798 }
799 
800 static struct gotd_child_proc *
801 find_proc_by_pid(pid_t pid)
802 {
803 	struct gotd_child_proc *proc = NULL;
804 
805 	TAILQ_FOREACH(proc, &procs, entry)
806 		if (proc->pid == pid)
807 			break;
808 
809 	return proc;
810 }
811 
812 void
813 gotd_sighdlr(int sig, short event, void *arg)
814 {
815 	struct gotd_child_proc *proc;
816 	pid_t pid;
817 	int status;
818 
819 	/*
820 	 * Normal signal handler rules don't apply because libevent
821 	 * decouples for us.
822 	 */
823 
824 	switch (sig) {
825 	case SIGHUP:
826 		log_info("%s: ignoring SIGHUP", __func__);
827 		break;
828 	case SIGUSR1:
829 		log_info("%s: ignoring SIGUSR1", __func__);
830 		break;
831 	case SIGTERM:
832 	case SIGINT:
833 		gotd_shutdown();
834 		break;
835 	case SIGCHLD:
836 		for (;;) {
837 			pid = waitpid(WAIT_ANY, &status, WNOHANG);
838 			if (pid == -1) {
839 				if (errno == EINTR)
840 					continue;
841 				if (errno == ECHILD)
842 					break;
843 				fatal("waitpid");
844 			}
845 			if (pid == 0)
846 				break;
847 
848 			log_debug("reaped pid %d", pid);
849 			proc = find_proc_by_pid(pid);
850 			if (proc == NULL) {
851 				log_info("caught exit of unknown child %d",
852 				    pid);
853 				continue;
854 			}
855 
856 			if (WIFSIGNALED(status)) {
857 				log_warnx("child PID %d terminated with"
858 				    " signal %d", pid, WTERMSIG(status));
859 			}
860 
861 			proc_done(proc);
862 		}
863 		break;
864 	default:
865 		fatalx("unexpected signal");
866 	}
867 }
868 
869 static const struct got_error *
870 ensure_proc_is_reading(struct gotd_client *client,
871     struct gotd_child_proc *proc)
872 {
873 	if (!client_is_reading(client)) {
874 		kill_proc(proc, 1);
875 		return got_error_fmt(GOT_ERR_BAD_PACKET,
876 		    "PID %d handled a read-request for uid %d but this "
877 		    "user is not reading from a repository", proc->pid,
878 		    client->euid);
879 	}
880 
881 	return NULL;
882 }
883 
884 static const struct got_error *
885 ensure_proc_is_writing(struct gotd_client *client,
886     struct gotd_child_proc *proc)
887 {
888 	if (!client_is_writing(client)) {
889 		kill_proc(proc, 1);
890 		return got_error_fmt(GOT_ERR_BAD_PACKET,
891 		    "PID %d handled a write-request for uid %d but this "
892 		    "user is not writing to a repository", proc->pid,
893 		    client->euid);
894 	}
895 
896 	return NULL;
897 }
898 
899 static int
900 verify_imsg_src(struct gotd_client *client, struct gotd_child_proc *proc,
901     struct imsg *imsg)
902 {
903 	const struct got_error *err;
904 	int ret = 0;
905 
906 	if (proc->type == PROC_REPO_READ || proc->type == PROC_REPO_WRITE) {
907 		if (client->repo == NULL)
908 			fatalx("no process found for uid %d", client->euid);
909 		if (proc->pid != client->repo->pid) {
910 			kill_proc(proc, 1);
911 			log_warnx("received message from PID %d for uid %d, "
912 			    "while PID %d is the process serving this user",
913 			    proc->pid, client->euid, client->repo->pid);
914 			return 0;
915 		}
916 	}
917 	if (proc->type == PROC_SESSION_READ ||
918 	    proc->type == PROC_SESSION_WRITE) {
919 		if (client->session == NULL) {
920 			log_warnx("no session found for uid %d", client->euid);
921 			return 0;
922 		}
923 		if (proc->pid != client->session->pid) {
924 			kill_proc(proc, 1);
925 			log_warnx("received message from PID %d for uid %d, "
926 			    "while PID %d is the process serving this user",
927 			    proc->pid, client->euid, client->session->pid);
928 			return 0;
929 		}
930 	}
931 
932 	switch (imsg->hdr.type) {
933 	case GOTD_IMSG_ERROR:
934 		ret = 1;
935 		break;
936 	case GOTD_IMSG_CONNECT:
937 		if (proc->type != PROC_LISTEN) {
938 			err = got_error_fmt(GOT_ERR_BAD_PACKET,
939 			    "new connection for uid %d from PID %d "
940 			    "which is not the listen process",
941 			    client->euid, proc->pid);
942 		} else
943 			ret = 1;
944 		break;
945 	case GOTD_IMSG_ACCESS_GRANTED:
946 		if (proc->type != PROC_AUTH) {
947 			err = got_error_fmt(GOT_ERR_BAD_PACKET,
948 			    "authentication of uid %d from PID %d "
949 			    "which is not the auth process",
950 			    client->euid, proc->pid);
951 		} else
952 			ret = 1;
953 		break;
954 	case GOTD_IMSG_CLIENT_SESSION_READY:
955 		if (proc->type != PROC_SESSION_READ &&
956 		    proc->type != PROC_SESSION_WRITE) {
957 			err = got_error_fmt(GOT_ERR_BAD_PACKET,
958 			    "unexpected \"ready\" signal from PID %d",
959 			    proc->pid);
960 		} else
961 			ret = 1;
962 		break;
963 	case GOTD_IMSG_REPO_CHILD_READY:
964 		if (proc->type != PROC_REPO_READ &&
965 		    proc->type != PROC_REPO_WRITE) {
966 			err = got_error_fmt(GOT_ERR_BAD_PACKET,
967 			    "unexpected \"ready\" signal from PID %d",
968 			    proc->pid);
969 		} else
970 			ret = 1;
971 		break;
972 	case GOTD_IMSG_PACKFILE_DONE:
973 		err = ensure_proc_is_reading(client, proc);
974 		if (err)
975 			log_warnx("uid %d: %s", client->euid, err->msg);
976 		else
977 			ret = 1;
978 		break;
979 	case GOTD_IMSG_PACKFILE_INSTALL:
980 	case GOTD_IMSG_REF_UPDATES_START:
981 	case GOTD_IMSG_REF_UPDATE:
982 		err = ensure_proc_is_writing(client, proc);
983 		if (err)
984 			log_warnx("uid %d: %s", client->euid, err->msg);
985 		else
986 			ret = 1;
987 		break;
988 	default:
989 		log_debug("%s: unexpected imsg %d", __func__, imsg->hdr.type);
990 		break;
991 	}
992 
993 	return ret;
994 }
995 
996 static const struct got_error *
997 connect_repo_child(struct gotd_client *client,
998     struct gotd_child_proc *repo_proc)
999 {
1000 	static const struct got_error *err;
1001 	struct gotd_imsgev *session_iev = &client->session->iev;
1002 	struct gotd_imsg_connect_repo_child ireq;
1003 	int pipe[2];
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_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK,
1010 	    PF_UNSPEC, pipe) == -1)
1011 		fatal("socketpair");
1012 
1013 	memset(&ireq, 0, sizeof(ireq));
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_notifier(int fd, short event, void *arg)
1125 {
1126 	struct gotd_imsgev *iev = arg;
1127 	struct imsgbuf *ibuf = &iev->ibuf;
1128 	struct gotd_child_proc *proc = gotd.notify_proc;
1129 	ssize_t n;
1130 	int shut = 0;
1131 	struct imsg imsg;
1132 
1133 	if (proc->iev.ibuf.fd != fd)
1134 		fatalx("%s: unexpected fd %d", __func__, fd);
1135 
1136 	if (event & EV_READ) {
1137 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
1138 			fatal("imsg_read error");
1139 		if (n == 0) {
1140 			/* Connection closed. */
1141 			shut = 1;
1142 			goto done;
1143 		}
1144 	}
1145 
1146 	if (event & EV_WRITE) {
1147 		n = msgbuf_write(&ibuf->w);
1148 		if (n == -1 && errno != EAGAIN)
1149 			fatal("msgbuf_write");
1150 		if (n == 0) {
1151 			/* Connection closed. */
1152 			shut = 1;
1153 			goto done;
1154 		}
1155 	}
1156 
1157 	for (;;) {
1158 		if ((n = imsg_get(ibuf, &imsg)) == -1)
1159 			fatal("%s: imsg_get error", __func__);
1160 		if (n == 0)	/* No more messages. */
1161 			break;
1162 
1163 		switch (imsg.hdr.type) {
1164 		default:
1165 			log_debug("unexpected imsg %d", imsg.hdr.type);
1166 			break;
1167 		}
1168 
1169 		imsg_free(&imsg);
1170 	}
1171 done:
1172 	if (!shut) {
1173 		gotd_imsg_event_add(iev);
1174 	} else {
1175 		/* This pipe is dead. Remove its event handler */
1176 		event_del(&iev->ev);
1177 
1178 		/*
1179 		 * Do not exit all of gotd if the notification handler dies.
1180 		 * We can continue operating without notifications until an
1181 		 * operator intervenes.
1182 		 */
1183 		log_warnx("notify child process (pid %d) closed its imsg pipe "
1184 		    "unexpectedly", proc->pid);
1185 		proc_done(proc);
1186 	}
1187 }
1188 
1189 static void
1190 gotd_dispatch_auth_child(int fd, short event, void *arg)
1191 {
1192 	const struct got_error *err = NULL;
1193 	struct gotd_imsgev *iev = arg;
1194 	struct imsgbuf *ibuf = &iev->ibuf;
1195 	struct gotd_client *client;
1196 	struct gotd_repo *repo = NULL;
1197 	ssize_t n;
1198 	int shut = 0;
1199 	struct imsg imsg;
1200 	uint32_t client_id = 0;
1201 	int do_disconnect = 0;
1202 	size_t datalen;
1203 
1204 	client = find_client_by_proc_fd(fd);
1205 	if (client == NULL) {
1206 		/* Can happen during process teardown. */
1207 		warnx("cannot find client for fd %d", fd);
1208 		shut = 1;
1209 		goto done;
1210 	}
1211 
1212 	if (client->auth == NULL)
1213 		fatalx("cannot find auth child process for fd %d", fd);
1214 
1215 	if (event & EV_READ) {
1216 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
1217 			fatal("imsg_read error");
1218 		if (n == 0) {
1219 			/* Connection closed. */
1220 			shut = 1;
1221 			goto done;
1222 		}
1223 	}
1224 
1225 	if (event & EV_WRITE) {
1226 		n = msgbuf_write(&ibuf->w);
1227 		if (n == -1 && errno != EAGAIN)
1228 			fatal("msgbuf_write");
1229 		if (n == 0) {
1230 			/* Connection closed. */
1231 			shut = 1;
1232 		}
1233 		goto done;
1234 	}
1235 
1236 	if (client->auth->iev.ibuf.fd != fd)
1237 		fatalx("%s: unexpected fd %d", __func__, fd);
1238 
1239 	if ((n = imsg_get(ibuf, &imsg)) == -1)
1240 		fatal("%s: imsg_get error", __func__);
1241 	if (n == 0)	/* No more messages. */
1242 		return;
1243 
1244 	evtimer_del(&client->tmo);
1245 
1246 	datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
1247 
1248 	switch (imsg.hdr.type) {
1249 	case GOTD_IMSG_ERROR:
1250 		do_disconnect = 1;
1251 		err = gotd_imsg_recv_error(&client_id, &imsg);
1252 		break;
1253 	case GOTD_IMSG_ACCESS_GRANTED:
1254 		if (client->state != GOTD_CLIENT_STATE_NEW) {
1255 			do_disconnect = 1;
1256 			err = got_error(GOT_ERR_PRIVSEP_MSG);
1257 		}
1258 		break;
1259 	default:
1260 		do_disconnect = 1;
1261 		log_debug("unexpected imsg %d", imsg.hdr.type);
1262 		break;
1263 	}
1264 
1265 	if (!verify_imsg_src(client, client->auth, &imsg)) {
1266 		do_disconnect = 1;
1267 		log_debug("dropping imsg type %d from PID %d",
1268 		    imsg.hdr.type, client->auth->pid);
1269 	}
1270 
1271 	if (do_disconnect) {
1272 		if (err)
1273 			disconnect_on_error(client, err);
1274 		else
1275 			disconnect(client);
1276 		imsg_free(&imsg);
1277 		return;
1278 	}
1279 
1280 	client->state = GOTD_CLIENT_STATE_ACCESS_GRANTED;
1281 	if (datalen > 0)
1282 		client->username = strndup(imsg.data, datalen);
1283 	imsg_free(&imsg);
1284 	if (client->username == NULL &&
1285 	    asprintf(&client->username, "uid %d", client->euid) == -1) {
1286 		err = got_error_from_errno("asprintf");
1287 		goto done;
1288 	}
1289 
1290 	repo = gotd_find_repo_by_name(client->auth->repo_name, &gotd.repos);
1291 	if (repo == NULL) {
1292 		err = got_error(GOT_ERR_NOT_GIT_REPO);
1293 		goto done;
1294 	}
1295 	kill_auth_proc(client);
1296 
1297 	log_info("authenticated %s for repository %s",
1298 	    client->username, repo->name);
1299 
1300 	err = start_session_child(client, repo, gotd.argv0,
1301 	    gotd.confpath, gotd.daemonize, gotd.verbosity);
1302 	if (err)
1303 		goto done;
1304 done:
1305 	if (err)
1306 		log_warnx("uid %d: %s", client->euid, err->msg);
1307 
1308 	/* We might have killed the auth process by now. */
1309 	if (client->auth != NULL) {
1310 		if (!shut) {
1311 			gotd_imsg_event_add(iev);
1312 		} else {
1313 			/* This pipe is dead. Remove its event handler */
1314 			event_del(&iev->ev);
1315 		}
1316 	}
1317 }
1318 
1319 static const struct got_error *
1320 connect_session(struct gotd_client *client)
1321 {
1322 	const struct got_error *err = NULL;
1323 	struct gotd_imsg_connect iconnect;
1324 	int s;
1325 	struct ibuf *wbuf;
1326 
1327 	memset(&iconnect, 0, sizeof(iconnect));
1328 
1329 	s = dup(client->fd);
1330 	if (s == -1)
1331 		return got_error_from_errno("dup");
1332 
1333 	iconnect.client_id = client->id;
1334 	iconnect.euid = client->euid;
1335 	iconnect.egid = client->egid;
1336 	iconnect.username_len = strlen(client->username);
1337 
1338 	wbuf = imsg_create(&client->session->iev.ibuf, GOTD_IMSG_CONNECT,
1339 	    PROC_GOTD, gotd.pid, sizeof(iconnect) + iconnect.username_len);
1340 	if (wbuf == NULL) {
1341 		err = got_error_from_errno("imsg compose CONNECT");
1342 		close(s);
1343 		return err;
1344 	}
1345 	if (imsg_add(wbuf, &iconnect, sizeof(iconnect)) == -1) {
1346 		close(s);
1347 		return got_error_from_errno("imsg_add CONNECT");
1348 	}
1349 	if (imsg_add(wbuf, client->username, iconnect.username_len) == -1) {
1350 		close(s);
1351 		return got_error_from_errno("imsg_add CONNECT");
1352 	}
1353 
1354 	ibuf_fd_set(wbuf, s);
1355 	imsg_close(&client->session->iev.ibuf, wbuf);
1356 	gotd_imsg_event_add(&client->session->iev);
1357 
1358 	/*
1359 	 * We are no longer interested in messages from this client.
1360 	 * Further client requests will be handled by the session process.
1361 	 */
1362 	msgbuf_clear(&client->iev.ibuf.w);
1363 	imsg_clear(&client->iev.ibuf);
1364 	event_del(&client->iev.ev);
1365 	client->fd = -1; /* will be closed via copy in client->iev.ibuf.fd */
1366 
1367 	return NULL;
1368 }
1369 
1370 static void
1371 gotd_dispatch_client_session(int fd, short event, void *arg)
1372 {
1373 	struct gotd_imsgev *iev = arg;
1374 	struct imsgbuf *ibuf = &iev->ibuf;
1375 	struct gotd_child_proc *proc = NULL;
1376 	struct gotd_client *client = NULL;
1377 	ssize_t n;
1378 	int shut = 0;
1379 	struct imsg imsg;
1380 
1381 	client = find_client_by_proc_fd(fd);
1382 	if (client == NULL) {
1383 		/* Can happen during process teardown. */
1384 		warnx("cannot find client for fd %d", fd);
1385 		shut = 1;
1386 		goto done;
1387 	}
1388 
1389 	if (event & EV_READ) {
1390 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
1391 			fatal("imsg_read error");
1392 		if (n == 0) {
1393 			/* Connection closed. */
1394 			shut = 1;
1395 			goto done;
1396 		}
1397 	}
1398 
1399 	if (event & EV_WRITE) {
1400 		n = msgbuf_write(&ibuf->w);
1401 		if (n == -1 && errno != EAGAIN)
1402 			fatal("msgbuf_write");
1403 		if (n == 0) {
1404 			/* Connection closed. */
1405 			shut = 1;
1406 			goto done;
1407 		}
1408 	}
1409 
1410 	proc = client->session;
1411 	if (proc == NULL)
1412 		fatalx("cannot find session child process for fd %d", fd);
1413 
1414 	for (;;) {
1415 		const struct got_error *err = NULL;
1416 		uint32_t client_id = 0;
1417 		int do_disconnect = 0, do_start_repo_child = 0;
1418 
1419 		if ((n = imsg_get(ibuf, &imsg)) == -1)
1420 			fatal("%s: imsg_get error", __func__);
1421 		if (n == 0)	/* No more messages. */
1422 			break;
1423 
1424 		switch (imsg.hdr.type) {
1425 		case GOTD_IMSG_ERROR:
1426 			do_disconnect = 1;
1427 			err = gotd_imsg_recv_error(&client_id, &imsg);
1428 			break;
1429 		case GOTD_IMSG_CLIENT_SESSION_READY:
1430 			if (client->state != GOTD_CLIENT_STATE_ACCESS_GRANTED) {
1431 				err = got_error(GOT_ERR_PRIVSEP_MSG);
1432 				break;
1433 			}
1434 			do_start_repo_child = 1;
1435 			break;
1436 		case GOTD_IMSG_DISCONNECT:
1437 			do_disconnect = 1;
1438 			break;
1439 		default:
1440 			log_debug("unexpected imsg %d", imsg.hdr.type);
1441 			break;
1442 		}
1443 
1444 		if (!verify_imsg_src(client, proc, &imsg)) {
1445 			log_debug("dropping imsg type %d from PID %d",
1446 			    imsg.hdr.type, proc->pid);
1447 			imsg_free(&imsg);
1448 			continue;
1449 		}
1450 		if (err)
1451 			log_warnx("uid %d: %s", client->euid, err->msg);
1452 
1453 		if (do_start_repo_child) {
1454 			struct gotd_repo *repo;
1455 			const char *name = client->session->repo_name;
1456 
1457 			repo = gotd_find_repo_by_name(name, &gotd.repos);
1458 			if (repo != NULL) {
1459 				enum gotd_procid proc_type;
1460 
1461 				if (client->required_auth & GOTD_AUTH_WRITE)
1462 					proc_type = PROC_REPO_WRITE;
1463 				else
1464 					proc_type = PROC_REPO_READ;
1465 
1466 				err = start_repo_child(client, proc_type, repo,
1467 				    gotd.argv0, gotd.confpath, gotd.daemonize,
1468 				    gotd.verbosity);
1469 			} else
1470 				err = got_error(GOT_ERR_NOT_GIT_REPO);
1471 
1472 			if (err) {
1473 				log_warnx("uid %d: %s", client->euid, err->msg);
1474 				do_disconnect = 1;
1475 			}
1476 		}
1477 
1478 		if (do_disconnect) {
1479 			if (err)
1480 				disconnect_on_error(client, err);
1481 			else
1482 				disconnect(client);
1483 		}
1484 
1485 		imsg_free(&imsg);
1486 	}
1487 done:
1488 	if (!shut) {
1489 		gotd_imsg_event_add(iev);
1490 	} else {
1491 		/* This pipe is dead. Remove its event handler */
1492 		event_del(&iev->ev);
1493 		disconnect(client);
1494 	}
1495 }
1496 
1497 static const struct got_error *
1498 connect_notifier_and_session(struct gotd_client *client)
1499 {
1500 	const struct got_error *err = NULL;
1501 	struct gotd_imsgev *session_iev = &client->session->iev;
1502 	int pipe[2];
1503 
1504 	if (gotd.notify_proc == NULL)
1505 		return NULL;
1506 
1507 	if (socketpair(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK,
1508 	    PF_UNSPEC, pipe) == -1)
1509 		return got_error_from_errno("socketpair");
1510 
1511 	/* Pass notifier pipe to session . */
1512 	if (gotd_imsg_compose_event(session_iev, GOTD_IMSG_CONNECT_NOTIFIER,
1513 	    PROC_GOTD, pipe[0], NULL, 0) == -1) {
1514 		err = got_error_from_errno("imsg compose CONNECT_NOTIFIER");
1515 		close(pipe[0]);
1516 		close(pipe[1]);
1517 		return err;
1518 	}
1519 
1520 	/* Pass session pipe to notifier. */
1521 	if (gotd_imsg_compose_event(&gotd.notify_proc->iev,
1522 	    GOTD_IMSG_CONNECT_SESSION, PROC_GOTD, pipe[1], NULL, 0) == -1) {
1523 		err = got_error_from_errno("imsg compose CONNECT_SESSION");
1524 		close(pipe[1]);
1525 		return err;
1526 	}
1527 
1528 	return NULL;
1529 }
1530 
1531 static void
1532 gotd_dispatch_repo_child(int fd, short event, void *arg)
1533 {
1534 	struct gotd_imsgev *iev = arg;
1535 	struct imsgbuf *ibuf = &iev->ibuf;
1536 	struct gotd_child_proc *proc = NULL;
1537 	struct gotd_client *client;
1538 	ssize_t n;
1539 	int shut = 0;
1540 	struct imsg imsg;
1541 
1542 	client = find_client_by_proc_fd(fd);
1543 	if (client == NULL) {
1544 		/* Can happen during process teardown. */
1545 		warnx("cannot find client for fd %d", fd);
1546 		shut = 1;
1547 		goto done;
1548 	}
1549 
1550 	if (event & EV_READ) {
1551 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
1552 			fatal("imsg_read error");
1553 		if (n == 0) {
1554 			/* Connection closed. */
1555 			shut = 1;
1556 			goto done;
1557 		}
1558 	}
1559 
1560 	if (event & EV_WRITE) {
1561 		n = msgbuf_write(&ibuf->w);
1562 		if (n == -1 && errno != EAGAIN)
1563 			fatal("msgbuf_write");
1564 		if (n == 0) {
1565 			/* Connection closed. */
1566 			shut = 1;
1567 			goto done;
1568 		}
1569 	}
1570 
1571 	proc = client->repo;
1572 	if (proc == NULL)
1573 		fatalx("cannot find child process for fd %d", fd);
1574 
1575 	for (;;) {
1576 		const struct got_error *err = NULL;
1577 		uint32_t client_id = 0;
1578 		int do_disconnect = 0;
1579 
1580 		if ((n = imsg_get(ibuf, &imsg)) == -1)
1581 			fatal("%s: imsg_get error", __func__);
1582 		if (n == 0)	/* No more messages. */
1583 			break;
1584 
1585 		switch (imsg.hdr.type) {
1586 		case GOTD_IMSG_ERROR:
1587 			do_disconnect = 1;
1588 			err = gotd_imsg_recv_error(&client_id, &imsg);
1589 			break;
1590 		case GOTD_IMSG_REPO_CHILD_READY:
1591 			err = connect_session(client);
1592 			if (err)
1593 				break;
1594 			err = connect_notifier_and_session(client);
1595 			if (err)
1596 				break;
1597 			err = connect_repo_child(client, proc);
1598 			break;
1599 		default:
1600 			log_debug("unexpected imsg %d", imsg.hdr.type);
1601 			break;
1602 		}
1603 
1604 		if (!verify_imsg_src(client, proc, &imsg)) {
1605 			log_debug("dropping imsg type %d from PID %d",
1606 			    imsg.hdr.type, proc->pid);
1607 			imsg_free(&imsg);
1608 			continue;
1609 		}
1610 		if (err)
1611 			log_warnx("uid %d: %s", client->euid, err->msg);
1612 
1613 		if (do_disconnect) {
1614 			if (err)
1615 				disconnect_on_error(client, err);
1616 			else
1617 				disconnect(client);
1618 		}
1619 
1620 		imsg_free(&imsg);
1621 	}
1622 done:
1623 	if (!shut) {
1624 		gotd_imsg_event_add(iev);
1625 	} else {
1626 		/* This pipe is dead. Remove its event handler */
1627 		event_del(&iev->ev);
1628 		disconnect(client);
1629 	}
1630 }
1631 
1632 static pid_t
1633 start_child(enum gotd_procid proc_id, const char *repo_path,
1634     char *argv0, const char *confpath, int fd, int daemonize, int verbosity)
1635 {
1636 	char	*argv[11];
1637 	int	 argc = 0;
1638 	pid_t	 pid;
1639 
1640 	switch (pid = fork()) {
1641 	case -1:
1642 		fatal("cannot fork");
1643 	case 0:
1644 		break;
1645 	default:
1646 		close(fd);
1647 		return pid;
1648 	}
1649 
1650 	if (fd != GOTD_FILENO_MSG_PIPE) {
1651 		if (dup2(fd, GOTD_FILENO_MSG_PIPE) == -1)
1652 			fatal("cannot setup imsg fd");
1653 	} else if (fcntl(fd, F_SETFD, 0) == -1)
1654 		fatal("cannot setup imsg fd");
1655 
1656 	argv[argc++] = argv0;
1657 	switch (proc_id) {
1658 	case PROC_LISTEN:
1659 		argv[argc++] = (char *)"-L";
1660 		break;
1661 	case PROC_AUTH:
1662 		argv[argc++] = (char *)"-A";
1663 		break;
1664 	case PROC_SESSION_READ:
1665 		argv[argc++] = (char *)"-s";
1666 		break;
1667 	case PROC_SESSION_WRITE:
1668 		argv[argc++] = (char *)"-S";
1669 		break;
1670 	case PROC_REPO_READ:
1671 		argv[argc++] = (char *)"-R";
1672 		break;
1673 	case PROC_REPO_WRITE:
1674 		argv[argc++] = (char *)"-W";
1675 		break;
1676 	case PROC_NOTIFY:
1677 		argv[argc++] = (char *)"-N";
1678 		break;
1679 	default:
1680 		fatalx("invalid process id %d", proc_id);
1681 	}
1682 
1683 	argv[argc++] = (char *)"-f";
1684 	argv[argc++] = (char *)confpath;
1685 
1686 	if (repo_path) {
1687 		argv[argc++] = (char *)"-P";
1688 		argv[argc++] = (char *)repo_path;
1689 	}
1690 
1691 	if (!daemonize)
1692 		argv[argc++] = (char *)"-d";
1693 	if (verbosity > 0)
1694 		argv[argc++] = (char *)"-v";
1695 	if (verbosity > 1)
1696 		argv[argc++] = (char *)"-v";
1697 	argv[argc++] = NULL;
1698 
1699 	execvp(argv0, argv);
1700 	fatal("execvp");
1701 }
1702 
1703 static void
1704 start_listener(char *argv0, const char *confpath, int daemonize, int verbosity)
1705 {
1706 	struct gotd_child_proc *proc;
1707 
1708 	proc = calloc(1, sizeof(*proc));
1709 	if (proc == NULL)
1710 		fatal("calloc");
1711 
1712 	TAILQ_INSERT_HEAD(&procs, proc, entry);
1713 
1714 	/* proc->tmo is initialized in main() after event_init() */
1715 
1716 	proc->type = PROC_LISTEN;
1717 
1718 	if (socketpair(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK,
1719 	    PF_UNSPEC, proc->pipe) == -1)
1720 		fatal("socketpair");
1721 
1722 	proc->pid = start_child(proc->type, NULL, argv0, confpath,
1723 	    proc->pipe[1], daemonize, verbosity);
1724 	imsg_init(&proc->iev.ibuf, proc->pipe[0]);
1725 	proc->iev.handler = gotd_dispatch_listener;
1726 	proc->iev.events = EV_READ;
1727 	proc->iev.handler_arg = NULL;
1728 
1729 	gotd.listen_proc = proc;
1730 }
1731 
1732 static void
1733 start_notifier(char *argv0, const char *confpath, int daemonize, int verbosity)
1734 {
1735 	struct gotd_child_proc *proc;
1736 
1737 	proc = calloc(1, sizeof(*proc));
1738 	if (proc == NULL)
1739 		fatal("calloc");
1740 
1741 	TAILQ_INSERT_HEAD(&procs, proc, entry);
1742 
1743 	/* proc->tmo is initialized in main() after event_init() */
1744 
1745 	proc->type = PROC_NOTIFY;
1746 
1747 	if (socketpair(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK,
1748 	    PF_UNSPEC, proc->pipe) == -1)
1749 		fatal("socketpair");
1750 
1751 	proc->pid = start_child(proc->type, NULL, argv0, confpath,
1752 	    proc->pipe[1], daemonize, verbosity);
1753 	imsg_init(&proc->iev.ibuf, proc->pipe[0]);
1754 	proc->iev.handler = gotd_dispatch_notifier;
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_notifier, &proc->iev);
1759 
1760 	gotd.notify_proc = proc;
1761 }
1762 
1763 static const struct got_error *
1764 start_session_child(struct gotd_client *client, struct gotd_repo *repo,
1765     char *argv0, const char *confpath, int daemonize, int verbosity)
1766 {
1767 	struct gotd_child_proc *proc;
1768 
1769 	proc = calloc(1, sizeof(*proc));
1770 	if (proc == NULL)
1771 		return got_error_from_errno("calloc");
1772 
1773 	TAILQ_INSERT_HEAD(&procs, proc, entry);
1774 	evtimer_set(&proc->tmo, kill_proc_timeout, proc);
1775 
1776 	if (client_is_reading(client))
1777 		proc->type = PROC_SESSION_READ;
1778 	else
1779 		proc->type = PROC_SESSION_WRITE;
1780 	if (strlcpy(proc->repo_name, repo->name,
1781 	    sizeof(proc->repo_name)) >= sizeof(proc->repo_name))
1782 		fatalx("repository name too long: %s", repo->name);
1783 	log_debug("starting client uid %d session for repository %s",
1784 	    client->euid, repo->name);
1785 	if (strlcpy(proc->repo_path, repo->path, sizeof(proc->repo_path)) >=
1786 	    sizeof(proc->repo_path))
1787 		fatalx("repository path too long: %s", repo->path);
1788 	if (socketpair(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK,
1789 	    PF_UNSPEC, proc->pipe) == -1)
1790 		fatal("socketpair");
1791 	proc->pid = start_child(proc->type, proc->repo_path, argv0,
1792 	    confpath, proc->pipe[1], daemonize, verbosity);
1793 	imsg_init(&proc->iev.ibuf, proc->pipe[0]);
1794 	log_debug("proc %s %s is on fd %d",
1795 	    gotd_proc_names[proc->type], proc->repo_path,
1796 	    proc->pipe[0]);
1797 	proc->iev.handler = gotd_dispatch_client_session;
1798 	proc->iev.events = EV_READ;
1799 	proc->iev.handler_arg = NULL;
1800 	event_set(&proc->iev.ev, proc->iev.ibuf.fd, EV_READ,
1801 	    gotd_dispatch_client_session, &proc->iev);
1802 	gotd_imsg_event_add(&proc->iev);
1803 
1804 	client->session = proc;
1805 	return NULL;
1806 }
1807 
1808 static const struct got_error *
1809 start_repo_child(struct gotd_client *client, enum gotd_procid proc_type,
1810     struct gotd_repo *repo, char *argv0, const char *confpath,
1811     int daemonize, int verbosity)
1812 {
1813 	struct gotd_child_proc *proc;
1814 
1815 	if (proc_type != PROC_REPO_READ && proc_type != PROC_REPO_WRITE)
1816 		return got_error_msg(GOT_ERR_NOT_IMPL, "bad process type");
1817 
1818 	proc = calloc(1, sizeof(*proc));
1819 	if (proc == NULL)
1820 		return got_error_from_errno("calloc");
1821 
1822 	TAILQ_INSERT_HEAD(&procs, proc, entry);
1823 	evtimer_set(&proc->tmo, kill_proc_timeout, proc);
1824 
1825 	proc->type = proc_type;
1826 	if (strlcpy(proc->repo_name, repo->name,
1827 	    sizeof(proc->repo_name)) >= sizeof(proc->repo_name))
1828 		fatalx("repository name too long: %s", repo->name);
1829 	log_debug("starting %s for repository %s",
1830 	    proc->type == PROC_REPO_READ ? "reader" : "writer", repo->name);
1831 	if (strlcpy(proc->repo_path, repo->path, sizeof(proc->repo_path)) >=
1832 	    sizeof(proc->repo_path))
1833 		fatalx("repository path too long: %s", repo->path);
1834 	if (socketpair(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK,
1835 	    PF_UNSPEC, proc->pipe) == -1)
1836 		fatal("socketpair");
1837 	proc->pid = start_child(proc->type, proc->repo_path, argv0,
1838 	    confpath, proc->pipe[1], daemonize, verbosity);
1839 	imsg_init(&proc->iev.ibuf, proc->pipe[0]);
1840 	log_debug("proc %s %s is on fd %d",
1841 	    gotd_proc_names[proc->type], proc->repo_path,
1842 	    proc->pipe[0]);
1843 	proc->iev.handler = gotd_dispatch_repo_child;
1844 	proc->iev.events = EV_READ;
1845 	proc->iev.handler_arg = NULL;
1846 	event_set(&proc->iev.ev, proc->iev.ibuf.fd, EV_READ,
1847 	    gotd_dispatch_repo_child, &proc->iev);
1848 	gotd_imsg_event_add(&proc->iev);
1849 
1850 	client->repo = proc;
1851 	return NULL;
1852 }
1853 
1854 static const struct got_error *
1855 start_auth_child(struct gotd_client *client, int required_auth,
1856     struct gotd_repo *repo, char *argv0, const char *confpath,
1857     int daemonize, int verbosity)
1858 {
1859 	const struct got_error *err = NULL;
1860 	struct gotd_child_proc *proc;
1861 	struct gotd_imsg_auth iauth;
1862 	int fd;
1863 
1864 	memset(&iauth, 0, sizeof(iauth));
1865 
1866 	fd = dup(client->fd);
1867 	if (fd == -1)
1868 		return got_error_from_errno("dup");
1869 
1870 	proc = calloc(1, sizeof(*proc));
1871 	if (proc == NULL) {
1872 		err = got_error_from_errno("calloc");
1873 		close(fd);
1874 		return err;
1875 	}
1876 
1877 	TAILQ_INSERT_HEAD(&procs, proc, entry);
1878 	evtimer_set(&proc->tmo, kill_proc_timeout, proc);
1879 
1880 	proc->type = PROC_AUTH;
1881 	if (strlcpy(proc->repo_name, repo->name,
1882 	    sizeof(proc->repo_name)) >= sizeof(proc->repo_name))
1883 		fatalx("repository name too long: %s", repo->name);
1884 	log_debug("starting auth for uid %d repository %s",
1885 	    client->euid, repo->name);
1886 	if (strlcpy(proc->repo_path, repo->path, sizeof(proc->repo_path)) >=
1887 	    sizeof(proc->repo_path))
1888 		fatalx("repository path too long: %s", repo->path);
1889 	if (socketpair(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK,
1890 	    PF_UNSPEC, proc->pipe) == -1)
1891 		fatal("socketpair");
1892 	proc->pid = start_child(proc->type, proc->repo_path, argv0,
1893 	    confpath, proc->pipe[1], daemonize, verbosity);
1894 	imsg_init(&proc->iev.ibuf, proc->pipe[0]);
1895 	log_debug("proc %s %s is on fd %d",
1896 	    gotd_proc_names[proc->type], proc->repo_path,
1897 	    proc->pipe[0]);
1898 	proc->iev.handler = gotd_dispatch_auth_child;
1899 	proc->iev.events = EV_READ;
1900 	proc->iev.handler_arg = NULL;
1901 	event_set(&proc->iev.ev, proc->iev.ibuf.fd, EV_READ,
1902 	    gotd_dispatch_auth_child, &proc->iev);
1903 	gotd_imsg_event_add(&proc->iev);
1904 
1905 	iauth.euid = client->euid;
1906 	iauth.egid = client->egid;
1907 	iauth.required_auth = required_auth;
1908 	iauth.client_id = client->id;
1909 	if (gotd_imsg_compose_event(&proc->iev, GOTD_IMSG_AUTHENTICATE,
1910 	    PROC_GOTD, fd, &iauth, sizeof(iauth)) == -1) {
1911 		log_warn("imsg compose AUTHENTICATE");
1912 		close(fd);
1913 		/* Let the auth_timeout handler tidy up. */
1914 	}
1915 
1916 	client->auth = proc;
1917 	client->required_auth = required_auth;
1918 	return NULL;
1919 }
1920 
1921 static void
1922 apply_unveil_repo_readonly(const char *repo_path, int need_tmpdir)
1923 {
1924 	if (need_tmpdir) {
1925 		if (unveil(GOT_TMPDIR_STR, "rwc") == -1)
1926 			fatal("unveil %s", GOT_TMPDIR_STR);
1927 	}
1928 
1929 	if (unveil(repo_path, "r") == -1)
1930 		fatal("unveil %s", repo_path);
1931 
1932 	if (unveil(NULL, NULL) == -1)
1933 		fatal("unveil");
1934 }
1935 
1936 static void
1937 apply_unveil_repo_readwrite(const char *repo_path)
1938 {
1939 	if (unveil(repo_path, "rwc") == -1)
1940 		fatal("unveil %s", repo_path);
1941 
1942 	if (unveil(GOT_TMPDIR_STR, "rwc") == -1)
1943 		fatal("unveil %s", GOT_TMPDIR_STR);
1944 
1945 	if (unveil(NULL, NULL) == -1)
1946 		fatal("unveil");
1947 }
1948 
1949 static void
1950 apply_unveil_none(void)
1951 {
1952 	if (unveil("/", "") == -1)
1953 		fatal("unveil");
1954 
1955 	if (unveil(NULL, NULL) == -1)
1956 		fatal("unveil");
1957 }
1958 
1959 static void
1960 apply_unveil_selfexec(void)
1961 {
1962 	if (unveil(gotd.argv0, "x") == -1)
1963 		fatal("unveil %s", gotd.argv0);
1964 
1965 	if (unveil(NULL, NULL) == -1)
1966 		fatal("unveil");
1967 }
1968 
1969 static void
1970 set_max_datasize(void)
1971 {
1972 	struct rlimit rl;
1973 
1974 	if (getrlimit(RLIMIT_DATA, &rl) != 0)
1975 		return;
1976 
1977 	rl.rlim_cur = rl.rlim_max;
1978 	setrlimit(RLIMIT_DATA, &rl);
1979 }
1980 
1981 static void
1982 unveil_notification_helpers(void)
1983 {
1984 	const char *helpers[] = {
1985 	    GOTD_PATH_PROG_NOTIFY_EMAIL,
1986 	    GOTD_PATH_PROG_NOTIFY_HTTP,
1987 	};
1988 	size_t i;
1989 
1990 	for (i = 0; i < nitems(helpers); i++) {
1991 		if (unveil(helpers[i], "x") == 0)
1992 			continue;
1993 		fatal("unveil %s", helpers[i]);
1994 	}
1995 
1996 	if (unveil(NULL, NULL) == -1)
1997 		fatal("unveil");
1998 }
1999 
2000 int
2001 main(int argc, char **argv)
2002 {
2003 	const struct got_error *error = NULL;
2004 	int ch, fd = -1, daemonize = 1, verbosity = 0, noaction = 0;
2005 	const char *confpath = GOTD_CONF_PATH;
2006 	char *argv0 = argv[0];
2007 	char title[2048];
2008 	struct passwd *pw = NULL;
2009 	char *repo_path = NULL;
2010 	enum gotd_procid proc_id = PROC_GOTD;
2011 	struct event evsigint, evsigterm, evsighup, evsigusr1, evsigchld;
2012 	int *pack_fds = NULL, *temp_fds = NULL;
2013 	struct gotd_repo *repo = NULL;
2014 	char *default_sender = NULL;
2015 	char hostname[HOST_NAME_MAX + 1];
2016 	FILE *diff_f1 = NULL, *diff_f2 = NULL;
2017 	int diff_fd1 = -1, diff_fd2 = -1;
2018 
2019 	TAILQ_INIT(&procs);
2020 
2021 	log_init(1, LOG_DAEMON); /* Log to stderr until daemonized. */
2022 
2023 	while ((ch = getopt(argc, argv, "Adf:LnNP:RsSvW")) != -1) {
2024 		switch (ch) {
2025 		case 'A':
2026 			proc_id = PROC_AUTH;
2027 			break;
2028 		case 'd':
2029 			daemonize = 0;
2030 			break;
2031 		case 'f':
2032 			confpath = optarg;
2033 			break;
2034 		case 'L':
2035 			proc_id = PROC_LISTEN;
2036 			break;
2037 		case 'n':
2038 			noaction = 1;
2039 			break;
2040 		case 'N':
2041 			proc_id = PROC_NOTIFY;
2042 			break;
2043 		case 'P':
2044 			repo_path = realpath(optarg, NULL);
2045 			if (repo_path == NULL)
2046 				fatal("realpath '%s'", optarg);
2047 			break;
2048 		case 'R':
2049 			proc_id = PROC_REPO_READ;
2050 			break;
2051 		case 's':
2052 			proc_id = PROC_SESSION_READ;
2053 			break;
2054 		case 'S':
2055 			proc_id = PROC_SESSION_WRITE;
2056 			break;
2057 		case 'v':
2058 			if (verbosity < 3)
2059 				verbosity++;
2060 			break;
2061 		case 'W':
2062 			proc_id = PROC_REPO_WRITE;
2063 			break;
2064 		default:
2065 			usage();
2066 		}
2067 	}
2068 
2069 	argc -= optind;
2070 	argv += optind;
2071 
2072 	if (argc != 0)
2073 		usage();
2074 
2075 	if (geteuid() && (proc_id == PROC_GOTD || proc_id == PROC_LISTEN))
2076 		fatalx("need root privileges");
2077 
2078 	if (parse_config(confpath, proc_id, &gotd) != 0)
2079 		return 1;
2080 
2081 	pw = getpwnam(gotd.user_name);
2082 	if (pw == NULL)
2083 		fatalx("user %s not found", gotd.user_name);
2084 
2085 	if (pw->pw_uid == 0)
2086 		fatalx("cannot run %s as the superuser", getprogname());
2087 
2088 	if (noaction) {
2089 		fprintf(stderr, "configuration OK\n");
2090 		return 0;
2091 	}
2092 
2093 	gotd.argv0 = argv0;
2094 	gotd.daemonize = daemonize;
2095 	gotd.verbosity = verbosity;
2096 	gotd.confpath = confpath;
2097 
2098 	/* Require an absolute path in argv[0] for reliable re-exec. */
2099 	if (!got_path_is_absolute(argv0))
2100 		fatalx("bad path \"%s\": must be an absolute path", argv0);
2101 
2102 	log_init(daemonize ? 0 : 1, LOG_DAEMON);
2103 	log_setverbose(verbosity);
2104 
2105 	if (proc_id == PROC_GOTD) {
2106 		snprintf(title, sizeof(title), "%s", gotd_proc_names[proc_id]);
2107 		arc4random_buf(&clients_hash_key, sizeof(clients_hash_key));
2108 		if (daemonize && daemon(1, 0) == -1)
2109 			fatal("daemon");
2110 		gotd.pid = getpid();
2111 		start_listener(argv0, confpath, daemonize, verbosity);
2112 		start_notifier(argv0, confpath, daemonize, verbosity);
2113 	} else if (proc_id == PROC_LISTEN) {
2114 		snprintf(title, sizeof(title), "%s", gotd_proc_names[proc_id]);
2115 		if (verbosity) {
2116 			log_info("socket: %s", gotd.unix_socket_path);
2117 			log_info("user: %s", pw->pw_name);
2118 		}
2119 
2120 		fd = unix_socket_listen(gotd.unix_socket_path, pw->pw_uid,
2121 		    pw->pw_gid);
2122 		if (fd == -1) {
2123 			fatal("cannot listen on unix socket %s",
2124 			    gotd.unix_socket_path);
2125 		}
2126 	} else if (proc_id == PROC_AUTH) {
2127 		snprintf(title, sizeof(title), "%s %s",
2128 		    gotd_proc_names[proc_id], repo_path);
2129 	} else if (proc_id == PROC_REPO_READ || proc_id == PROC_REPO_WRITE ||
2130 	    proc_id == PROC_SESSION_READ || proc_id == PROC_SESSION_WRITE) {
2131 		error = got_repo_pack_fds_open(&pack_fds);
2132 		if (error != NULL)
2133 			fatalx("cannot open pack tempfiles: %s", error->msg);
2134 		error = got_repo_temp_fds_open(&temp_fds);
2135 		if (error != NULL)
2136 			fatalx("cannot open pack tempfiles: %s", error->msg);
2137 		if (repo_path == NULL)
2138 			fatalx("repository path not specified");
2139 		snprintf(title, sizeof(title), "%s %s",
2140 		    gotd_proc_names[proc_id], repo_path);
2141 	} else if (proc_id == PROC_NOTIFY) {
2142 		snprintf(title, sizeof(title), "%s", gotd_proc_names[proc_id]);
2143 		if (gethostname(hostname, sizeof(hostname)) == -1)
2144 			fatal("gethostname");
2145 		if (asprintf(&default_sender, "%s@%s",
2146 		    pw->pw_name, hostname) == -1)
2147 			fatal("asprintf");
2148 	} else
2149 		fatal("invalid process id %d", proc_id);
2150 
2151 	setproctitle("%s", title);
2152 	log_procinit(title);
2153 
2154 	/* Drop root privileges. */
2155 	if (setgid(pw->pw_gid) == -1)
2156 		fatal("setgid %d failed", pw->pw_gid);
2157 	if (setuid(pw->pw_uid) == -1)
2158 		fatal("setuid %d failed", pw->pw_uid);
2159 
2160 	event_init();
2161 
2162 	switch (proc_id) {
2163 	case PROC_GOTD:
2164 #ifndef PROFILE
2165 		/* "exec" promise will be limited to argv[0] via unveil(2). */
2166 		if (pledge("stdio proc exec sendfd recvfd unveil", NULL) == -1)
2167 			err(1, "pledge");
2168 #endif
2169 		break;
2170 	case PROC_LISTEN:
2171 #ifndef PROFILE
2172 		if (pledge("stdio sendfd unix unveil", NULL) == -1)
2173 			err(1, "pledge");
2174 #endif
2175 		/*
2176 		 * Ensure that AF_UNIX bind(2) cannot be used with any other
2177 		 * sockets by revoking all filesystem access via unveil(2).
2178 		 */
2179 		apply_unveil_none();
2180 
2181 		listen_main(title, fd, gotd.connection_limits,
2182 		    gotd.nconnection_limits);
2183 		/* NOTREACHED */
2184 		break;
2185 	case PROC_AUTH:
2186 #ifndef PROFILE
2187 		if (pledge("stdio getpw recvfd unix unveil", NULL) == -1)
2188 			err(1, "pledge");
2189 #endif
2190 		/*
2191 		 * We need the "unix" pledge promise for getpeername(2) only.
2192 		 * Ensure that AF_UNIX bind(2) cannot be used by revoking all
2193 		 * filesystem access via unveil(2). Access to password database
2194 		 * files will still work since "getpw" bypasses unveil(2).
2195 		 */
2196 		apply_unveil_none();
2197 
2198 		auth_main(title, &gotd.repos, repo_path);
2199 		/* NOTREACHED */
2200 		break;
2201 	case PROC_SESSION_READ:
2202 	case PROC_SESSION_WRITE:
2203 #ifndef PROFILE
2204 		/*
2205 		 * The "recvfd" promise is only needed during setup and
2206 		 * will be removed in a later pledge(2) call.
2207 		 */
2208 		if (pledge("stdio rpath wpath cpath recvfd sendfd fattr flock "
2209 		    "unveil", NULL) == -1)
2210 			err(1, "pledge");
2211 #endif
2212 		if (proc_id == PROC_SESSION_READ)
2213 			apply_unveil_repo_readonly(repo_path, 1);
2214 		else {
2215 			apply_unveil_repo_readwrite(repo_path);
2216 			repo = gotd_find_repo_by_path(repo_path, &gotd);
2217 			if (repo == NULL)
2218 				fatalx("no repository for path %s", repo_path);
2219 		}
2220 		session_main(title, repo_path, pack_fds, temp_fds,
2221 		    &gotd.request_timeout, repo, proc_id);
2222 		/* NOTREACHED */
2223 		break;
2224 	case PROC_REPO_READ:
2225 		set_max_datasize();
2226 #ifndef PROFILE
2227 		if (pledge("stdio rpath recvfd unveil", NULL) == -1)
2228 			err(1, "pledge");
2229 #endif
2230 		apply_unveil_repo_readonly(repo_path, 0);
2231 		repo_read_main(title, repo_path, pack_fds, temp_fds);
2232 		/* NOTREACHED */
2233 		exit(0);
2234 	case PROC_REPO_WRITE:
2235 		set_max_datasize();
2236 
2237 		diff_f1 = got_opentemp();
2238 		if (diff_f1 == NULL)
2239 			fatal("got_opentemp");
2240 		diff_f2 = got_opentemp();
2241 		if (diff_f2 == NULL)
2242 			fatal("got_opentemp");
2243 		diff_fd1 = got_opentempfd();
2244 		if (diff_fd1 == -1)
2245 			fatal("got_opentempfd");
2246 		diff_fd2 = got_opentempfd();
2247 		if (diff_fd2 == -1)
2248 			fatal("got_opentempfd");
2249 #ifndef PROFILE
2250 		if (pledge("stdio rpath recvfd unveil", NULL) == -1)
2251 			err(1, "pledge");
2252 #endif
2253 		apply_unveil_repo_readonly(repo_path, 0);
2254 		repo = gotd_find_repo_by_path(repo_path, &gotd);
2255 		if (repo == NULL)
2256 			fatalx("no repository for path %s", repo_path);
2257 		repo_write_main(title, repo_path, pack_fds, temp_fds,
2258 		    diff_f1, diff_f2, diff_fd1, diff_fd2,
2259 		    &repo->protected_tag_namespaces,
2260 		    &repo->protected_branch_namespaces,
2261 		    &repo->protected_branches);
2262 		/* NOTREACHED */
2263 		exit(0);
2264 	case PROC_NOTIFY:
2265 #ifndef PROFILE
2266 		if (pledge("stdio proc exec recvfd unveil", NULL) == -1)
2267 			err(1, "pledge");
2268 #endif
2269 		/*
2270 		 * Limit "exec" promise to notification helpers via unveil(2).
2271 		 */
2272 		unveil_notification_helpers();
2273 
2274 		notify_main(title, &gotd.repos, default_sender);
2275 		/* NOTREACHED */
2276 		exit(0);
2277 	default:
2278 		fatal("invalid process id %d", proc_id);
2279 	}
2280 
2281 	if (proc_id != PROC_GOTD)
2282 		fatal("invalid process id %d", proc_id);
2283 
2284 	evtimer_set(&gotd.listen_proc->tmo, kill_proc_timeout,
2285 	    gotd.listen_proc);
2286 	if (gotd.notify_proc) {
2287 		evtimer_set(&gotd.notify_proc->tmo, kill_proc_timeout,
2288 		    gotd.notify_proc);
2289 	}
2290 
2291 	apply_unveil_selfexec();
2292 
2293 	signal_set(&evsigint, SIGINT, gotd_sighdlr, NULL);
2294 	signal_set(&evsigterm, SIGTERM, gotd_sighdlr, NULL);
2295 	signal_set(&evsighup, SIGHUP, gotd_sighdlr, NULL);
2296 	signal_set(&evsigusr1, SIGUSR1, gotd_sighdlr, NULL);
2297 	signal_set(&evsigchld, SIGCHLD, gotd_sighdlr, NULL);
2298 	signal(SIGPIPE, SIG_IGN);
2299 
2300 	signal_add(&evsigint, NULL);
2301 	signal_add(&evsigterm, NULL);
2302 	signal_add(&evsighup, NULL);
2303 	signal_add(&evsigusr1, NULL);
2304 	signal_add(&evsigchld, NULL);
2305 
2306 	gotd_imsg_event_add(&gotd.listen_proc->iev);
2307 	if (gotd.notify_proc)
2308 		gotd_imsg_event_add(&gotd.notify_proc->iev);
2309 
2310 	event_dispatch();
2311 
2312 	free(repo_path);
2313 	free(default_sender);
2314 	gotd_shutdown();
2315 
2316 	return 0;
2317 }