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 #include <sys/resource.h>
27 
28 #include <fcntl.h>
29 #include <err.h>
30 #include <errno.h>
31 #include <event.h>
32 #include <limits.h>
33 #include <pwd.h>
34 #include <imsg.h>
35 #include <signal.h>
36 #include <stdarg.h>
37 #include <stdio.h>
38 #include <stdlib.h>
39 #include <string.h>
40 #include <syslog.h>
41 #include <unistd.h>
42 
43 #include "got_error.h"
44 #include "got_opentemp.h"
45 #include "got_path.h"
46 #include "got_repository.h"
47 #include "got_object.h"
48 #include "got_reference.h"
49 #include "got_diff.h"
50 
51 #include "got_lib_delta.h"
52 #include "got_lib_object.h"
53 #include "got_lib_object_cache.h"
54 #include "got_lib_hash.h"
55 #include "got_lib_gitproto.h"
56 #include "got_lib_pack.h"
57 #include "got_lib_repository.h"
58 
59 #include "gotd.h"
60 #include "log.h"
61 #include "listen.h"
62 #include "auth.h"
63 #include "session.h"
64 #include "repo_read.h"
65 #include "repo_write.h"
66 #include "notify.h"
67 
68 #ifndef nitems
69 #define nitems(_a)	(sizeof((_a)) / sizeof((_a)[0]))
70 #endif
71 
72 enum gotd_client_state {
73 	GOTD_CLIENT_STATE_NEW,
74 	GOTD_CLIENT_STATE_ACCESS_GRANTED,
75 };
76 
77 struct gotd_child_proc {
78 	pid_t				 pid;
79 	enum gotd_procid		 type;
80 	char				 repo_name[NAME_MAX];
81 	char				 repo_path[PATH_MAX];
82 	int				 pipe[2];
83 	struct gotd_imsgev		 iev;
84 	struct event			 tmo;
85 
86 	TAILQ_ENTRY(gotd_child_proc)	 entry;
87 };
88 TAILQ_HEAD(gotd_procs, gotd_child_proc) procs;
89 
90 struct gotd_client {
91 	STAILQ_ENTRY(gotd_client)	 entry;
92 	enum gotd_client_state		 state;
93 	uint32_t			 id;
94 	int				 fd;
95 	struct gotd_imsgev		 iev;
96 	struct event			 tmo;
97 	uid_t				 euid;
98 	gid_t				 egid;
99 	char				*username;
100 	struct gotd_child_proc		*repo;
101 	struct gotd_child_proc		*auth;
102 	struct gotd_child_proc		*session;
103 	int				 required_auth;
104 };
105 STAILQ_HEAD(gotd_clients, gotd_client);
106 
107 static struct gotd_clients gotd_clients[GOTD_CLIENT_TABLE_SIZE];
108 static SIPHASH_KEY clients_hash_key;
109 volatile int client_cnt;
110 static struct timeval auth_timeout = { 5, 0 };
111 static struct gotd gotd;
112 
113 void gotd_sighdlr(int sig, short event, void *arg);
114 static void gotd_shutdown(void);
115 static const struct got_error *start_session_child(struct gotd_client *,
116     struct gotd_repo *, char *, const char *, int, int);
117 static const struct got_error *start_repo_child(struct gotd_client *,
118     enum gotd_procid, struct gotd_repo *, char *, const char *, int, int);
119 static const struct got_error *start_auth_child(struct gotd_client *, int,
120     struct gotd_repo *, char *, const char *, int, int);
121 static void kill_proc(struct gotd_child_proc *, int);
122 static void disconnect(struct gotd_client *);
123 static void drop_privs(struct passwd *);
124 
125 __dead static void
126 usage(void)
127 {
128 	fprintf(stderr, "usage: %s [-dnv] [-f config-file]\n", getprogname());
129 	exit(1);
130 }
131 
132 static void
133 drop_privs(struct passwd *pw)
134 {
135 	/* Drop root privileges. */
136 	if (setgid(pw->pw_gid) == -1)
137 		fatal("setgid %d failed", pw->pw_gid);
138 	if (setuid(pw->pw_uid) == -1)
139 		fatal("setuid %d failed", pw->pw_uid);
140 }
141 
142 static int
143 unix_socket_listen(const char *unix_socket_path, uid_t uid, gid_t gid)
144 {
145 	struct sockaddr_un sun;
146 	int fd = -1;
147 	mode_t old_umask, mode;
148 	int sock_flags = SOCK_STREAM | SOCK_NONBLOCK;
149 
150 #ifdef SOCK_CLOEXEC
151 	sock_flags |= SOCK_CLOEXEC;
152 #endif
153 
154 	fd = socket(AF_UNIX, sock_flags, 0);
155 	if (fd == -1) {
156 		log_warn("socket");
157 		return -1;
158 	}
159 
160 	sun.sun_family = AF_UNIX;
161 	if (strlcpy(sun.sun_path, unix_socket_path,
162 	    sizeof(sun.sun_path)) >= sizeof(sun.sun_path)) {
163 		log_warnx("%s: name too long", unix_socket_path);
164 		close(fd);
165 		return -1;
166 	}
167 
168 	if (unlink(unix_socket_path) == -1) {
169 		if (errno != ENOENT) {
170 			log_warn("unlink %s", unix_socket_path);
171 			close(fd);
172 			return -1;
173 		}
174 	}
175 
176 	old_umask = umask(S_IXUSR|S_IXGRP|S_IWOTH|S_IROTH|S_IXOTH);
177 	mode = S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH;
178 
179 	if (bind(fd, (struct sockaddr *)&sun, sizeof(sun)) == -1) {
180 		log_warn("bind: %s", unix_socket_path);
181 		close(fd);
182 		umask(old_umask);
183 		return -1;
184 	}
185 
186 	umask(old_umask);
187 
188 	if (chmod(unix_socket_path, mode) == -1) {
189 		log_warn("chmod %o %s", mode, unix_socket_path);
190 		close(fd);
191 		unlink(unix_socket_path);
192 		return -1;
193 	}
194 
195 	if (chown(unix_socket_path, uid, gid) == -1) {
196 		log_warn("chown %s uid=%d gid=%d", unix_socket_path, uid, gid);
197 		close(fd);
198 		unlink(unix_socket_path);
199 		return -1;
200 	}
201 
202 	if (listen(fd, GOTD_UNIX_SOCKET_BACKLOG) == -1) {
203 		log_warn("listen");
204 		close(fd);
205 		unlink(unix_socket_path);
206 		return -1;
207 	}
208 
209 	return fd;
210 }
211 
212 static uint64_t
213 client_hash(uint32_t client_id)
214 {
215 	return SipHash24(&clients_hash_key, &client_id, sizeof(client_id));
216 }
217 
218 static void
219 add_client(struct gotd_client *client)
220 {
221 	uint64_t slot = client_hash(client->id) % nitems(gotd_clients);
222 	STAILQ_INSERT_HEAD(&gotd_clients[slot], client, entry);
223 	client_cnt++;
224 }
225 
226 static struct gotd_client *
227 find_client(uint32_t client_id)
228 {
229 	uint64_t slot;
230 	struct gotd_client *c;
231 
232 	slot = client_hash(client_id) % nitems(gotd_clients);
233 	STAILQ_FOREACH(c, &gotd_clients[slot], entry) {
234 		if (c->id == client_id)
235 			return c;
236 	}
237 
238 	return NULL;
239 }
240 
241 static struct gotd_client *
242 find_client_by_proc_fd(int fd)
243 {
244 	uint64_t slot;
245 
246 	for (slot = 0; slot < nitems(gotd_clients); slot++) {
247 		struct gotd_client *c;
248 
249 		STAILQ_FOREACH(c, &gotd_clients[slot], entry) {
250 			if (c->repo && c->repo->iev.ibuf.fd == fd)
251 				return c;
252 			if (c->auth && c->auth->iev.ibuf.fd == fd)
253 				return c;
254 			if (c->session && c->session->iev.ibuf.fd == fd)
255 				return c;
256 		}
257 	}
258 
259 	return NULL;
260 }
261 
262 static int
263 client_is_reading(struct gotd_client *client)
264 {
265 	return (client->required_auth &
266 	    (GOTD_AUTH_READ | GOTD_AUTH_WRITE)) == GOTD_AUTH_READ;
267 }
268 
269 static int
270 client_is_writing(struct gotd_client *client)
271 {
272 	return (client->required_auth &
273 	    (GOTD_AUTH_READ | GOTD_AUTH_WRITE)) ==
274 	    (GOTD_AUTH_READ | GOTD_AUTH_WRITE);
275 }
276 
277 static const struct got_error *
278 ensure_client_is_not_writing(struct gotd_client *client)
279 {
280 	if (client_is_writing(client)) {
281 		return got_error_fmt(GOT_ERR_BAD_PACKET,
282 		    "uid %d made a read-request but is writing to "
283 		    "a repository", client->euid);
284 	}
285 
286 	return NULL;
287 }
288 
289 static const struct got_error *
290 ensure_client_is_not_reading(struct gotd_client *client)
291 {
292 	if (client_is_reading(client)) {
293 		return got_error_fmt(GOT_ERR_BAD_PACKET,
294 		    "uid %d made a write-request but is reading from "
295 		    "a repository", client->euid);
296 	}
297 
298 	return NULL;
299 }
300 
301 static void
302 proc_done(struct gotd_child_proc *proc)
303 {
304 	struct gotd_client *client;
305 
306 	TAILQ_REMOVE(&procs, proc, entry);
307 
308 	client = find_client_by_proc_fd(proc->iev.ibuf.fd);
309 	if (client != NULL) {
310 		if (proc == client->repo)
311 			client->repo = NULL;
312 		if (proc == client->auth)
313 			client->auth = NULL;
314 		if (proc == client->session)
315 			client->session = NULL;
316 		disconnect(client);
317 	}
318 
319 	if (proc == gotd.notify_proc)
320 		gotd.notify_proc = NULL;
321 
322 	evtimer_del(&proc->tmo);
323 
324 	if (proc->iev.ibuf.fd != -1) {
325 		event_del(&proc->iev.ev);
326 		msgbuf_clear(&proc->iev.ibuf.w);
327 		close(proc->iev.ibuf.fd);
328 	}
329 
330 	free(proc);
331 }
332 
333 static void
334 kill_repo_proc(struct gotd_client *client)
335 {
336 	if (client->repo == NULL)
337 		return;
338 
339 	kill_proc(client->repo, 0);
340 	client->repo = NULL;
341 }
342 
343 static void
344 kill_auth_proc(struct gotd_client *client)
345 {
346 	if (client->auth == NULL)
347 		return;
348 
349 	kill_proc(client->auth, 0);
350 	client->auth = NULL;
351 }
352 
353 static void
354 kill_session_proc(struct gotd_client *client)
355 {
356 	if (client->session == NULL)
357 		return;
358 
359 	kill_proc(client->session, 0);
360 	client->session = NULL;
361 }
362 
363 static void
364 disconnect(struct gotd_client *client)
365 {
366 	struct gotd_imsg_disconnect idisconnect;
367 	struct gotd_child_proc *listen_proc = gotd.listen_proc;
368 	uint64_t slot;
369 
370 	log_debug("uid %d: disconnecting", client->euid);
371 
372 	kill_auth_proc(client);
373 	kill_session_proc(client);
374 	kill_repo_proc(client);
375 
376 	idisconnect.client_id = client->id;
377 	if (gotd_imsg_compose_event(&listen_proc->iev,
378 	    GOTD_IMSG_DISCONNECT, PROC_GOTD, -1,
379 	    &idisconnect, sizeof(idisconnect)) == -1)
380 		log_warn("imsg compose DISCONNECT");
381 
382 	slot = client_hash(client->id) % nitems(gotd_clients);
383 	STAILQ_REMOVE(&gotd_clients[slot], client, gotd_client, entry);
384 	imsg_clear(&client->iev.ibuf);
385 	event_del(&client->iev.ev);
386 	evtimer_del(&client->tmo);
387 	if (client->fd != -1)
388 		close(client->fd);
389 	else if (client->iev.ibuf.fd != -1)
390 		close(client->iev.ibuf.fd);
391 	free(client->username);
392 	free(client);
393 	client_cnt--;
394 }
395 
396 static void
397 disconnect_on_error(struct gotd_client *client, const struct got_error *err)
398 {
399 	struct imsgbuf ibuf;
400 
401 	if (err->code != GOT_ERR_EOF) {
402 		log_warnx("uid %d: %s", client->euid, err->msg);
403 		if (client->fd != -1) {
404 			imsg_init(&ibuf, client->fd);
405 			gotd_imsg_send_error(&ibuf, 0, PROC_GOTD, err);
406 			imsg_clear(&ibuf);
407 		}
408 	}
409 	disconnect(client);
410 }
411 
412 static const struct got_error *
413 send_repo_info(struct gotd_imsgev *iev, struct gotd_repo *repo)
414 {
415 	const struct got_error *err = NULL;
416 	struct gotd_imsg_info_repo irepo;
417 
418 	memset(&irepo, 0, sizeof(irepo));
419 
420 	if (strlcpy(irepo.repo_name, repo->name, sizeof(irepo.repo_name))
421 	    >= sizeof(irepo.repo_name))
422 		return got_error_msg(GOT_ERR_NO_SPACE, "repo name too long");
423 	if (strlcpy(irepo.repo_path, repo->path, sizeof(irepo.repo_path))
424 	    >= sizeof(irepo.repo_path))
425 		return got_error_msg(GOT_ERR_NO_SPACE, "repo path too long");
426 
427 	if (gotd_imsg_compose_event(iev, GOTD_IMSG_INFO_REPO, PROC_GOTD, -1,
428 	    &irepo, sizeof(irepo)) == -1) {
429 		err = got_error_from_errno("imsg compose INFO_REPO");
430 		if (err)
431 			return err;
432 	}
433 
434 	return NULL;
435 }
436 
437 static const struct got_error *
438 send_client_info(struct gotd_imsgev *iev, struct gotd_client *client)
439 {
440 	const struct got_error *err = NULL;
441 	struct gotd_imsg_info_client iclient;
442 	struct gotd_child_proc *proc;
443 
444 	memset(&iclient, 0, sizeof(iclient));
445 	iclient.euid = client->euid;
446 	iclient.egid = client->egid;
447 
448 	proc = client->repo;
449 	if (proc) {
450 		if (strlcpy(iclient.repo_name, proc->repo_path,
451 		    sizeof(iclient.repo_name)) >= sizeof(iclient.repo_name)) {
452 			return got_error_msg(GOT_ERR_NO_SPACE,
453 			    "repo name too long");
454 		}
455 		if (client_is_writing(client))
456 			iclient.is_writing = 1;
457 
458 		iclient.repo_child_pid = proc->pid;
459 	}
460 
461 	if (client->session)
462 		iclient.session_child_pid = client->session->pid;
463 
464 	if (gotd_imsg_compose_event(iev, GOTD_IMSG_INFO_CLIENT, PROC_GOTD, -1,
465 	    &iclient, sizeof(iclient)) == -1) {
466 		err = got_error_from_errno("imsg compose INFO_CLIENT");
467 		if (err)
468 			return err;
469 	}
470 
471 	return NULL;
472 }
473 
474 static const struct got_error *
475 send_info(struct gotd_client *client)
476 {
477 	const struct got_error *err = NULL;
478 	struct gotd_imsg_info info;
479 	uint64_t slot;
480 	struct gotd_repo *repo;
481 
482 	if (client->euid != 0)
483 		return got_error_set_errno(EPERM, "info");
484 
485 	info.pid = gotd.pid;
486 	info.verbosity = gotd.verbosity;
487 	info.nrepos = gotd.nrepos;
488 	info.nclients = client_cnt - 1;
489 
490 	if (gotd_imsg_compose_event(&client->iev, GOTD_IMSG_INFO, PROC_GOTD, -1,
491 	    &info, sizeof(info)) == -1) {
492 		err = got_error_from_errno("imsg compose INFO");
493 		if (err)
494 			return err;
495 	}
496 
497 	TAILQ_FOREACH(repo, &gotd.repos, entry) {
498 		err = send_repo_info(&client->iev, repo);
499 		if (err)
500 			return err;
501 	}
502 
503 	for (slot = 0; slot < nitems(gotd_clients); slot++) {
504 		struct gotd_client *c;
505 		STAILQ_FOREACH(c, &gotd_clients[slot], entry) {
506 			if (c->id == client->id)
507 				continue;
508 			err = send_client_info(&client->iev, c);
509 			if (err)
510 				return err;
511 		}
512 	}
513 
514 	return NULL;
515 }
516 
517 static const struct got_error *
518 stop_gotd(struct gotd_client *client)
519 {
520 
521 	if (client->euid != 0)
522 		return got_error_set_errno(EPERM, "stop");
523 
524 	gotd_shutdown();
525 	/* NOTREACHED */
526 	return NULL;
527 }
528 
529 static const struct got_error *
530 start_client_authentication(struct gotd_client *client, struct imsg *imsg)
531 {
532 	const struct got_error *err;
533 	struct gotd_imsg_list_refs ireq;
534 	struct gotd_repo *repo = NULL;
535 	size_t datalen;
536 
537 	log_debug("list-refs request from uid %d", client->euid);
538 
539 	if (client->state != GOTD_CLIENT_STATE_NEW)
540 		return got_error_msg(GOT_ERR_BAD_REQUEST,
541 		    "unexpected list-refs request received");
542 
543 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
544 	if (datalen != sizeof(ireq))
545 		return got_error(GOT_ERR_PRIVSEP_LEN);
546 
547 	memcpy(&ireq, imsg->data, datalen);
548 
549 	if (ireq.client_is_reading) {
550 		err = ensure_client_is_not_writing(client);
551 		if (err)
552 			return err;
553 		repo = gotd_find_repo_by_name(ireq.repo_name, &gotd.repos);
554 		if (repo == NULL)
555 			return got_error(GOT_ERR_NOT_GIT_REPO);
556 		err = start_auth_child(client, GOTD_AUTH_READ, repo,
557 		    gotd.argv0, gotd.confpath, gotd.daemonize,
558 		    gotd.verbosity);
559 		if (err)
560 			return err;
561 	} else {
562 		err = ensure_client_is_not_reading(client);
563 		if (err)
564 			return err;
565 		repo = gotd_find_repo_by_name(ireq.repo_name, &gotd.repos);
566 		if (repo == NULL)
567 			return got_error(GOT_ERR_NOT_GIT_REPO);
568 		err = start_auth_child(client,
569 		    GOTD_AUTH_READ | GOTD_AUTH_WRITE,
570 		    repo, gotd.argv0, gotd.confpath, gotd.daemonize,
571 		    gotd.verbosity);
572 		if (err)
573 			return err;
574 	}
575 
576 	evtimer_add(&client->tmo, &auth_timeout);
577 
578 	/* Flow continues upon authentication success/failure or timeout. */
579 	return NULL;
580 }
581 
582 static void
583 gotd_request(int fd, short events, void *arg)
584 {
585 	struct gotd_imsgev *iev = arg;
586 	struct imsgbuf *ibuf = &iev->ibuf;
587 	struct gotd_client *client = iev->handler_arg;
588 	const struct got_error *err = NULL;
589 	struct imsg imsg;
590 	ssize_t n;
591 
592 	if (events & EV_WRITE) {
593 		while (ibuf->w.queued) {
594 			n = msgbuf_write(&ibuf->w);
595 			if (n == -1 && errno == EPIPE) {
596 				/*
597 				 * The client has closed its socket.
598 				 * This can happen when Git clients are
599 				 * done sending pack file data.
600 				 */
601 				msgbuf_clear(&ibuf->w);
602 				continue;
603 			} else if (n == -1 && errno != EAGAIN) {
604 				err = got_error_from_errno("imsg_flush");
605 				disconnect_on_error(client, err);
606 				return;
607 			}
608 			if (n == 0) {
609 				/* Connection closed. */
610 				err = got_error(GOT_ERR_EOF);
611 				disconnect_on_error(client, err);
612 				return;
613 			}
614 		}
615 
616 		/* Disconnect gotctl(8) now that messages have been sent. */
617 		if (!client_is_reading(client) && !client_is_writing(client)) {
618 			disconnect(client);
619 			return;
620 		}
621 	}
622 
623 	if ((events & EV_READ) == 0)
624 		return;
625 
626 	memset(&imsg, 0, sizeof(imsg));
627 
628 	while (err == NULL) {
629 		err = gotd_imsg_recv(&imsg, ibuf, 0);
630 		if (err) {
631 			if (err->code == GOT_ERR_PRIVSEP_READ)
632 				err = NULL;
633 			break;
634 		}
635 
636 		evtimer_del(&client->tmo);
637 
638 		switch (imsg.hdr.type) {
639 		case GOTD_IMSG_INFO:
640 			err = send_info(client);
641 			break;
642 		case GOTD_IMSG_STOP:
643 			err = stop_gotd(client);
644 			break;
645 		case GOTD_IMSG_LIST_REFS:
646 			err = start_client_authentication(client, &imsg);
647 			break;
648 		default:
649 			log_debug("unexpected imsg %d", imsg.hdr.type);
650 			err = got_error(GOT_ERR_PRIVSEP_MSG);
651 			break;
652 		}
653 
654 		imsg_free(&imsg);
655 	}
656 
657 	if (err) {
658 		disconnect_on_error(client, err);
659 	} else {
660 		gotd_imsg_event_add(&client->iev);
661 	}
662 }
663 
664 static void
665 gotd_auth_timeout(int fd, short events, void *arg)
666 {
667 	struct gotd_client *client = arg;
668 
669 	log_debug("disconnecting uid %d due to authentication timeout",
670 	    client->euid);
671 	disconnect(client);
672 }
673 
674 static const struct got_error *
675 recv_connect(uint32_t *client_id, struct imsg *imsg)
676 {
677 	const struct got_error *err = NULL;
678 	struct gotd_imsg_connect iconnect;
679 	size_t datalen;
680 	int s = -1;
681 	struct gotd_client *client = NULL;
682 
683 	*client_id = 0;
684 
685 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
686 	if (datalen != sizeof(iconnect))
687 		return got_error(GOT_ERR_PRIVSEP_LEN);
688 	memcpy(&iconnect, imsg->data, sizeof(iconnect));
689 
690 	s = imsg_get_fd(imsg);
691 	if (s == -1) {
692 		err = got_error(GOT_ERR_PRIVSEP_NO_FD);
693 		goto done;
694 	}
695 
696 	if (find_client(iconnect.client_id)) {
697 		err = got_error_msg(GOT_ERR_CLIENT_ID, "duplicate client ID");
698 		goto done;
699 	}
700 
701 	client = calloc(1, sizeof(*client));
702 	if (client == NULL) {
703 		err = got_error_from_errno("calloc");
704 		goto done;
705 	}
706 
707 	*client_id = iconnect.client_id;
708 
709 	client->state = GOTD_CLIENT_STATE_NEW;
710 	client->id = iconnect.client_id;
711 	client->fd = s;
712 	s = -1;
713 	/* The auth process will verify UID/GID for us. */
714 	client->euid = iconnect.euid;
715 	client->egid = iconnect.egid;
716 
717 	imsg_init(&client->iev.ibuf, client->fd);
718 	client->iev.handler = gotd_request;
719 	client->iev.events = EV_READ;
720 	client->iev.handler_arg = client;
721 
722 	event_set(&client->iev.ev, client->fd, EV_READ, gotd_request,
723 	    &client->iev);
724 	gotd_imsg_event_add(&client->iev);
725 
726 	evtimer_set(&client->tmo, gotd_auth_timeout, client);
727 
728 	add_client(client);
729 	log_debug("%s: new client uid %d connected on fd %d", __func__,
730 	    client->euid, client->fd);
731 done:
732 	if (err) {
733 		struct gotd_child_proc *listen_proc = gotd.listen_proc;
734 		struct gotd_imsg_disconnect idisconnect;
735 
736 		idisconnect.client_id = client->id;
737 		if (gotd_imsg_compose_event(&listen_proc->iev,
738 		    GOTD_IMSG_DISCONNECT, PROC_GOTD, -1,
739 		    &idisconnect, sizeof(idisconnect)) == -1)
740 			log_warn("imsg compose DISCONNECT");
741 
742 		if (s != -1)
743 			close(s);
744 	}
745 
746 	return err;
747 }
748 
749 static const char *gotd_proc_names[PROC_MAX] = {
750 	"parent",
751 	"listen",
752 	"auth",
753 	"session_read",
754 	"session_write",
755 	"repo_read",
756 	"repo_write",
757 	"gitwrapper",
758 	"notify"
759 };
760 
761 static void
762 kill_proc(struct gotd_child_proc *proc, int fatal)
763 {
764 	struct timeval tv = { 5, 0 };
765 
766 	log_debug("kill -%d %d", fatal ? SIGKILL : SIGTERM, proc->pid);
767 
768 	if (proc->iev.ibuf.fd != -1) {
769 		event_del(&proc->iev.ev);
770 		msgbuf_clear(&proc->iev.ibuf.w);
771 		close(proc->iev.ibuf.fd);
772 		proc->iev.ibuf.fd = -1;
773 	}
774 
775 	if (!evtimer_pending(&proc->tmo, NULL) && !fatal)
776 		evtimer_add(&proc->tmo, &tv);
777 
778 	if (fatal) {
779 		log_warnx("sending SIGKILL to PID %d", proc->pid);
780 		kill(proc->pid, SIGKILL);
781 	} else
782 		kill(proc->pid, SIGTERM);
783 }
784 
785 static void
786 kill_proc_timeout(int fd, short ev, void *d)
787 {
788 	struct gotd_child_proc *proc = d;
789 
790 	log_warnx("timeout waiting for PID %d to terminate;"
791 	    " retrying with force", proc->pid);
792 	kill_proc(proc, 1);
793 }
794 
795 static void
796 gotd_shutdown(void)
797 {
798 	uint64_t slot;
799 
800 	log_debug("shutting down");
801 	for (slot = 0; slot < nitems(gotd_clients); slot++) {
802 		struct gotd_client *c, *tmp;
803 
804 		STAILQ_FOREACH_SAFE(c, &gotd_clients[slot], entry, tmp)
805 			disconnect(c);
806 	}
807 
808 	kill_proc(gotd.listen_proc, 0);
809 
810 	log_info("terminating");
811 	exit(0);
812 }
813 
814 static struct gotd_child_proc *
815 find_proc_by_pid(pid_t pid)
816 {
817 	struct gotd_child_proc *proc = NULL;
818 
819 	TAILQ_FOREACH(proc, &procs, entry)
820 		if (proc->pid == pid)
821 			break;
822 
823 	return proc;
824 }
825 
826 void
827 gotd_sighdlr(int sig, short event, void *arg)
828 {
829 	struct gotd_child_proc *proc;
830 	pid_t pid;
831 	int status;
832 
833 	/*
834 	 * Normal signal handler rules don't apply because libevent
835 	 * decouples for us.
836 	 */
837 
838 	switch (sig) {
839 	case SIGHUP:
840 		log_info("%s: ignoring SIGHUP", __func__);
841 		break;
842 	case SIGUSR1:
843 		log_info("%s: ignoring SIGUSR1", __func__);
844 		break;
845 	case SIGTERM:
846 	case SIGINT:
847 		gotd_shutdown();
848 		break;
849 	case SIGCHLD:
850 		for (;;) {
851 			pid = waitpid(WAIT_ANY, &status, WNOHANG);
852 			if (pid == -1) {
853 				if (errno == EINTR)
854 					continue;
855 				if (errno == ECHILD)
856 					break;
857 				fatal("waitpid");
858 			}
859 			if (pid == 0)
860 				break;
861 
862 			log_debug("reaped pid %d", pid);
863 			proc = find_proc_by_pid(pid);
864 			if (proc == NULL) {
865 				log_info("caught exit of unknown child %d",
866 				    pid);
867 				continue;
868 			}
869 
870 			if (WIFSIGNALED(status)) {
871 				log_warnx("child PID %d terminated with"
872 				    " signal %d", pid, WTERMSIG(status));
873 			}
874 
875 			proc_done(proc);
876 		}
877 		break;
878 	default:
879 		fatalx("unexpected signal");
880 	}
881 }
882 
883 static const struct got_error *
884 ensure_proc_is_reading(struct gotd_client *client,
885     struct gotd_child_proc *proc)
886 {
887 	if (!client_is_reading(client)) {
888 		kill_proc(proc, 1);
889 		return got_error_fmt(GOT_ERR_BAD_PACKET,
890 		    "PID %d handled a read-request for uid %d but this "
891 		    "user is not reading from a repository", proc->pid,
892 		    client->euid);
893 	}
894 
895 	return NULL;
896 }
897 
898 static const struct got_error *
899 ensure_proc_is_writing(struct gotd_client *client,
900     struct gotd_child_proc *proc)
901 {
902 	if (!client_is_writing(client)) {
903 		kill_proc(proc, 1);
904 		return got_error_fmt(GOT_ERR_BAD_PACKET,
905 		    "PID %d handled a write-request for uid %d but this "
906 		    "user is not writing to a repository", proc->pid,
907 		    client->euid);
908 	}
909 
910 	return NULL;
911 }
912 
913 static int
914 verify_imsg_src(struct gotd_client *client, struct gotd_child_proc *proc,
915     struct imsg *imsg)
916 {
917 	const struct got_error *err;
918 	int ret = 0;
919 
920 	if (proc->type == PROC_REPO_READ || proc->type == PROC_REPO_WRITE) {
921 		if (client->repo == NULL)
922 			fatalx("no process found for uid %d", client->euid);
923 		if (proc->pid != client->repo->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->repo->pid);
928 			return 0;
929 		}
930 	}
931 	if (proc->type == PROC_SESSION_READ ||
932 	    proc->type == PROC_SESSION_WRITE) {
933 		if (client->session == NULL) {
934 			log_warnx("no session found for uid %d", client->euid);
935 			return 0;
936 		}
937 		if (proc->pid != client->session->pid) {
938 			kill_proc(proc, 1);
939 			log_warnx("received message from PID %d for uid %d, "
940 			    "while PID %d is the process serving this user",
941 			    proc->pid, client->euid, client->session->pid);
942 			return 0;
943 		}
944 	}
945 
946 	switch (imsg->hdr.type) {
947 	case GOTD_IMSG_ERROR:
948 		ret = 1;
949 		break;
950 	case GOTD_IMSG_CONNECT:
951 		if (proc->type != PROC_LISTEN) {
952 			err = got_error_fmt(GOT_ERR_BAD_PACKET,
953 			    "new connection for uid %d from PID %d "
954 			    "which is not the listen process",
955 			    client->euid, proc->pid);
956 		} else
957 			ret = 1;
958 		break;
959 	case GOTD_IMSG_ACCESS_GRANTED:
960 		if (proc->type != PROC_AUTH) {
961 			err = got_error_fmt(GOT_ERR_BAD_PACKET,
962 			    "authentication of uid %d from PID %d "
963 			    "which is not the auth process",
964 			    client->euid, proc->pid);
965 		} else
966 			ret = 1;
967 		break;
968 	case GOTD_IMSG_CLIENT_SESSION_READY:
969 		if (proc->type != PROC_SESSION_READ &&
970 		    proc->type != PROC_SESSION_WRITE) {
971 			err = got_error_fmt(GOT_ERR_BAD_PACKET,
972 			    "unexpected \"ready\" signal from PID %d",
973 			    proc->pid);
974 		} else
975 			ret = 1;
976 		break;
977 	case GOTD_IMSG_REPO_CHILD_READY:
978 		if (proc->type != PROC_REPO_READ &&
979 		    proc->type != PROC_REPO_WRITE) {
980 			err = got_error_fmt(GOT_ERR_BAD_PACKET,
981 			    "unexpected \"ready\" signal from PID %d",
982 			    proc->pid);
983 		} else
984 			ret = 1;
985 		break;
986 	case GOTD_IMSG_PACKFILE_DONE:
987 		err = ensure_proc_is_reading(client, proc);
988 		if (err)
989 			log_warnx("uid %d: %s", client->euid, err->msg);
990 		else
991 			ret = 1;
992 		break;
993 	case GOTD_IMSG_PACKFILE_INSTALL:
994 	case GOTD_IMSG_REF_UPDATES_START:
995 	case GOTD_IMSG_REF_UPDATE:
996 		err = ensure_proc_is_writing(client, proc);
997 		if (err)
998 			log_warnx("uid %d: %s", client->euid, err->msg);
999 		else
1000 			ret = 1;
1001 		break;
1002 	default:
1003 		log_debug("%s: unexpected imsg %d", __func__, imsg->hdr.type);
1004 		break;
1005 	}
1006 
1007 	return ret;
1008 }
1009 
1010 static const struct got_error *
1011 connect_repo_child(struct gotd_client *client,
1012     struct gotd_child_proc *repo_proc)
1013 {
1014 	static const struct got_error *err;
1015 	struct gotd_imsgev *session_iev = &client->session->iev;
1016 	struct gotd_imsg_connect_repo_child ireq;
1017 	int pipe[2];
1018 	int sock_flags = SOCK_STREAM | SOCK_NONBLOCK;
1019 
1020 #ifdef SOCK_CLOEXEC
1021 	sock_flags |= SOCK_CLOEXEC;
1022 #endif
1023 
1024 	if (client->state != GOTD_CLIENT_STATE_ACCESS_GRANTED)
1025 		return got_error_msg(GOT_ERR_BAD_REQUEST,
1026 		    "unexpected repo child ready signal received");
1027 
1028 	if (socketpair(AF_UNIX, sock_flags, PF_UNSPEC, pipe) == -1)
1029 		fatal("socketpair");
1030 
1031 	memset(&ireq, 0, sizeof(ireq));
1032 	ireq.proc_id = repo_proc->type;
1033 
1034 	/* Pass repo child pipe to session child process. */
1035 	if (gotd_imsg_compose_event(session_iev, GOTD_IMSG_CONNECT_REPO_CHILD,
1036 	    PROC_GOTD, pipe[0], &ireq, sizeof(ireq)) == -1) {
1037 		err = got_error_from_errno("imsg compose CONNECT_REPO_CHILD");
1038 		close(pipe[0]);
1039 		close(pipe[1]);
1040 		return err;
1041 	}
1042 
1043 	/* Pass session child pipe to repo child process. */
1044 	if (gotd_imsg_compose_event(&repo_proc->iev,
1045 	    GOTD_IMSG_CONNECT_REPO_CHILD, PROC_GOTD, pipe[1], NULL, 0) == -1) {
1046 		err = got_error_from_errno("imsg compose CONNECT_REPO_CHILD");
1047 		close(pipe[1]);
1048 		return err;
1049 	}
1050 
1051 	return NULL;
1052 }
1053 
1054 static void
1055 gotd_dispatch_listener(int fd, short event, void *arg)
1056 {
1057 	struct gotd_imsgev *iev = arg;
1058 	struct imsgbuf *ibuf = &iev->ibuf;
1059 	struct gotd_child_proc *proc = gotd.listen_proc;
1060 	ssize_t n;
1061 	int shut = 0;
1062 	struct imsg imsg;
1063 
1064 	if (proc->iev.ibuf.fd != fd)
1065 		fatalx("%s: unexpected fd %d", __func__, fd);
1066 
1067 	if (event & EV_READ) {
1068 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
1069 			fatal("imsg_read error");
1070 		if (n == 0) {
1071 			/* Connection closed. */
1072 			shut = 1;
1073 			goto done;
1074 		}
1075 	}
1076 
1077 	if (event & EV_WRITE) {
1078 		n = msgbuf_write(&ibuf->w);
1079 		if (n == -1 && errno != EAGAIN)
1080 			fatal("msgbuf_write");
1081 		if (n == 0) {
1082 			/* Connection closed. */
1083 			shut = 1;
1084 			goto done;
1085 		}
1086 	}
1087 
1088 	for (;;) {
1089 		const struct got_error *err = NULL;
1090 		struct gotd_client *client = NULL;
1091 		uint32_t client_id = 0;
1092 		int do_disconnect = 0;
1093 
1094 		if ((n = imsg_get(ibuf, &imsg)) == -1)
1095 			fatal("%s: imsg_get error", __func__);
1096 		if (n == 0)	/* No more messages. */
1097 			break;
1098 
1099 		switch (imsg.hdr.type) {
1100 		case GOTD_IMSG_ERROR:
1101 			do_disconnect = 1;
1102 			err = gotd_imsg_recv_error(&client_id, &imsg);
1103 			break;
1104 		case GOTD_IMSG_CONNECT:
1105 			err = recv_connect(&client_id, &imsg);
1106 			break;
1107 		default:
1108 			log_debug("unexpected imsg %d", imsg.hdr.type);
1109 			break;
1110 		}
1111 
1112 		client = find_client(client_id);
1113 		if (client == NULL) {
1114 			log_warnx("%s: client not found", __func__);
1115 			imsg_free(&imsg);
1116 			continue;
1117 		}
1118 
1119 		if (err)
1120 			log_warnx("uid %d: %s", client->euid, err->msg);
1121 
1122 		if (do_disconnect) {
1123 			if (err)
1124 				disconnect_on_error(client, err);
1125 			else
1126 				disconnect(client);
1127 		}
1128 
1129 		imsg_free(&imsg);
1130 	}
1131 done:
1132 	if (!shut) {
1133 		gotd_imsg_event_add(iev);
1134 	} else {
1135 		/* This pipe is dead. Remove its event handler */
1136 		event_del(&iev->ev);
1137 		event_loopexit(NULL);
1138 	}
1139 }
1140 
1141 static void
1142 gotd_dispatch_notifier(int fd, short event, void *arg)
1143 {
1144 	struct gotd_imsgev *iev = arg;
1145 	struct imsgbuf *ibuf = &iev->ibuf;
1146 	struct gotd_child_proc *proc = gotd.notify_proc;
1147 	ssize_t n;
1148 	int shut = 0;
1149 	struct imsg imsg;
1150 
1151 	if (proc->iev.ibuf.fd != fd)
1152 		fatalx("%s: unexpected fd %d", __func__, fd);
1153 
1154 	if (event & EV_READ) {
1155 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
1156 			fatal("imsg_read error");
1157 		if (n == 0) {
1158 			/* Connection closed. */
1159 			shut = 1;
1160 			goto done;
1161 		}
1162 	}
1163 
1164 	if (event & EV_WRITE) {
1165 		n = msgbuf_write(&ibuf->w);
1166 		if (n == -1 && errno != EAGAIN)
1167 			fatal("msgbuf_write");
1168 		if (n == 0) {
1169 			/* Connection closed. */
1170 			shut = 1;
1171 			goto done;
1172 		}
1173 	}
1174 
1175 	for (;;) {
1176 		if ((n = imsg_get(ibuf, &imsg)) == -1)
1177 			fatal("%s: imsg_get error", __func__);
1178 		if (n == 0)	/* No more messages. */
1179 			break;
1180 
1181 		switch (imsg.hdr.type) {
1182 		default:
1183 			log_debug("unexpected imsg %d", imsg.hdr.type);
1184 			break;
1185 		}
1186 
1187 		imsg_free(&imsg);
1188 	}
1189 done:
1190 	if (!shut) {
1191 		gotd_imsg_event_add(iev);
1192 	} else {
1193 		/* This pipe is dead. Remove its event handler */
1194 		event_del(&iev->ev);
1195 
1196 		/*
1197 		 * Do not exit all of gotd if the notification handler dies.
1198 		 * We can continue operating without notifications until an
1199 		 * operator intervenes.
1200 		 */
1201 		log_warnx("notify child process (pid %d) closed its imsg pipe "
1202 		    "unexpectedly", proc->pid);
1203 		proc_done(proc);
1204 	}
1205 }
1206 
1207 static void
1208 gotd_dispatch_auth_child(int fd, short event, void *arg)
1209 {
1210 	const struct got_error *err = NULL;
1211 	struct gotd_imsgev *iev = arg;
1212 	struct imsgbuf *ibuf = &iev->ibuf;
1213 	struct gotd_client *client;
1214 	struct gotd_repo *repo = NULL;
1215 	ssize_t n;
1216 	int shut = 0;
1217 	struct imsg imsg;
1218 	uint32_t client_id = 0;
1219 	int do_disconnect = 0;
1220 	size_t datalen;
1221 
1222 	client = find_client_by_proc_fd(fd);
1223 	if (client == NULL) {
1224 		/* Can happen during process teardown. */
1225 		warnx("cannot find client for fd %d", fd);
1226 		shut = 1;
1227 		goto done;
1228 	}
1229 
1230 	if (client->auth == NULL)
1231 		fatalx("cannot find auth child process for fd %d", fd);
1232 
1233 	if (event & EV_READ) {
1234 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
1235 			fatal("imsg_read error");
1236 		if (n == 0) {
1237 			/* Connection closed. */
1238 			shut = 1;
1239 			goto done;
1240 		}
1241 	}
1242 
1243 	if (event & EV_WRITE) {
1244 		n = msgbuf_write(&ibuf->w);
1245 		if (n == -1 && errno != EAGAIN)
1246 			fatal("msgbuf_write");
1247 		if (n == 0) {
1248 			/* Connection closed. */
1249 			shut = 1;
1250 		}
1251 		goto done;
1252 	}
1253 
1254 	if (client->auth->iev.ibuf.fd != fd)
1255 		fatalx("%s: unexpected fd %d", __func__, fd);
1256 
1257 	if ((n = imsg_get(ibuf, &imsg)) == -1)
1258 		fatal("%s: imsg_get error", __func__);
1259 	if (n == 0)	/* No more messages. */
1260 		return;
1261 
1262 	evtimer_del(&client->tmo);
1263 
1264 	datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
1265 
1266 	switch (imsg.hdr.type) {
1267 	case GOTD_IMSG_ERROR:
1268 		do_disconnect = 1;
1269 		err = gotd_imsg_recv_error(&client_id, &imsg);
1270 		break;
1271 	case GOTD_IMSG_ACCESS_GRANTED:
1272 		if (client->state != GOTD_CLIENT_STATE_NEW) {
1273 			do_disconnect = 1;
1274 			err = got_error(GOT_ERR_PRIVSEP_MSG);
1275 		}
1276 		break;
1277 	default:
1278 		do_disconnect = 1;
1279 		log_debug("unexpected imsg %d", imsg.hdr.type);
1280 		break;
1281 	}
1282 
1283 	if (!verify_imsg_src(client, client->auth, &imsg)) {
1284 		do_disconnect = 1;
1285 		log_debug("dropping imsg type %d from PID %d",
1286 		    imsg.hdr.type, client->auth->pid);
1287 	}
1288 
1289 	if (do_disconnect) {
1290 		if (err)
1291 			disconnect_on_error(client, err);
1292 		else
1293 			disconnect(client);
1294 		imsg_free(&imsg);
1295 		return;
1296 	}
1297 
1298 	client->state = GOTD_CLIENT_STATE_ACCESS_GRANTED;
1299 	if (datalen > 0)
1300 		client->username = strndup(imsg.data, datalen);
1301 	imsg_free(&imsg);
1302 	if (client->username == NULL &&
1303 	    asprintf(&client->username, "uid %d", client->euid) == -1) {
1304 		err = got_error_from_errno("asprintf");
1305 		goto done;
1306 	}
1307 
1308 	repo = gotd_find_repo_by_name(client->auth->repo_name, &gotd.repos);
1309 	if (repo == NULL) {
1310 		err = got_error(GOT_ERR_NOT_GIT_REPO);
1311 		goto done;
1312 	}
1313 	kill_auth_proc(client);
1314 
1315 	log_info("authenticated %s for repository %s",
1316 	    client->username, repo->name);
1317 
1318 	err = start_session_child(client, repo, gotd.argv0,
1319 	    gotd.confpath, gotd.daemonize, gotd.verbosity);
1320 	if (err)
1321 		goto done;
1322 done:
1323 	if (err)
1324 		log_warnx("uid %d: %s", client->euid, err->msg);
1325 
1326 	/* We might have killed the auth process by now. */
1327 	if (client->auth != NULL) {
1328 		if (!shut) {
1329 			gotd_imsg_event_add(iev);
1330 		} else {
1331 			/* This pipe is dead. Remove its event handler */
1332 			event_del(&iev->ev);
1333 		}
1334 	}
1335 }
1336 
1337 static const struct got_error *
1338 connect_session(struct gotd_client *client)
1339 {
1340 	const struct got_error *err = NULL;
1341 	struct gotd_imsg_connect iconnect;
1342 	int s;
1343 	struct ibuf *wbuf;
1344 
1345 	memset(&iconnect, 0, sizeof(iconnect));
1346 
1347 	s = dup(client->fd);
1348 	if (s == -1)
1349 		return got_error_from_errno("dup");
1350 
1351 	iconnect.client_id = client->id;
1352 	iconnect.euid = client->euid;
1353 	iconnect.egid = client->egid;
1354 	iconnect.username_len = strlen(client->username);
1355 
1356 	wbuf = imsg_create(&client->session->iev.ibuf, GOTD_IMSG_CONNECT,
1357 	    PROC_GOTD, gotd.pid, sizeof(iconnect) + iconnect.username_len);
1358 	if (wbuf == NULL) {
1359 		err = got_error_from_errno("imsg compose CONNECT");
1360 		close(s);
1361 		return err;
1362 	}
1363 	if (imsg_add(wbuf, &iconnect, sizeof(iconnect)) == -1) {
1364 		close(s);
1365 		return got_error_from_errno("imsg_add CONNECT");
1366 	}
1367 	if (imsg_add(wbuf, client->username, iconnect.username_len) == -1) {
1368 		close(s);
1369 		return got_error_from_errno("imsg_add CONNECT");
1370 	}
1371 
1372 	ibuf_fd_set(wbuf, s);
1373 	imsg_close(&client->session->iev.ibuf, wbuf);
1374 	gotd_imsg_event_add(&client->session->iev);
1375 
1376 	/*
1377 	 * We are no longer interested in messages from this client.
1378 	 * Further client requests will be handled by the session process.
1379 	 */
1380 	msgbuf_clear(&client->iev.ibuf.w);
1381 	imsg_clear(&client->iev.ibuf);
1382 	event_del(&client->iev.ev);
1383 	client->fd = -1; /* will be closed via copy in client->iev.ibuf.fd */
1384 
1385 	return NULL;
1386 }
1387 
1388 static void
1389 gotd_dispatch_client_session(int fd, short event, void *arg)
1390 {
1391 	struct gotd_imsgev *iev = arg;
1392 	struct imsgbuf *ibuf = &iev->ibuf;
1393 	struct gotd_child_proc *proc = NULL;
1394 	struct gotd_client *client = NULL;
1395 	ssize_t n;
1396 	int shut = 0;
1397 	struct imsg imsg;
1398 
1399 	client = find_client_by_proc_fd(fd);
1400 	if (client == NULL) {
1401 		/* Can happen during process teardown. */
1402 		warnx("cannot find client for fd %d", fd);
1403 		shut = 1;
1404 		goto done;
1405 	}
1406 
1407 	if (event & EV_READ) {
1408 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
1409 			fatal("imsg_read error");
1410 		if (n == 0) {
1411 			/* Connection closed. */
1412 			shut = 1;
1413 			goto done;
1414 		}
1415 	}
1416 
1417 	if (event & EV_WRITE) {
1418 		n = msgbuf_write(&ibuf->w);
1419 		if (n == -1 && errno != EAGAIN)
1420 			fatal("msgbuf_write");
1421 		if (n == 0) {
1422 			/* Connection closed. */
1423 			shut = 1;
1424 			goto done;
1425 		}
1426 	}
1427 
1428 	proc = client->session;
1429 	if (proc == NULL)
1430 		fatalx("cannot find session child process for fd %d", fd);
1431 
1432 	for (;;) {
1433 		const struct got_error *err = NULL;
1434 		uint32_t client_id = 0;
1435 		int do_disconnect = 0, do_start_repo_child = 0;
1436 
1437 		if ((n = imsg_get(ibuf, &imsg)) == -1)
1438 			fatal("%s: imsg_get error", __func__);
1439 		if (n == 0)	/* No more messages. */
1440 			break;
1441 
1442 		switch (imsg.hdr.type) {
1443 		case GOTD_IMSG_ERROR:
1444 			do_disconnect = 1;
1445 			err = gotd_imsg_recv_error(&client_id, &imsg);
1446 			break;
1447 		case GOTD_IMSG_CLIENT_SESSION_READY:
1448 			if (client->state != GOTD_CLIENT_STATE_ACCESS_GRANTED) {
1449 				err = got_error(GOT_ERR_PRIVSEP_MSG);
1450 				break;
1451 			}
1452 			do_start_repo_child = 1;
1453 			break;
1454 		case GOTD_IMSG_DISCONNECT:
1455 			do_disconnect = 1;
1456 			break;
1457 		default:
1458 			log_debug("unexpected imsg %d", imsg.hdr.type);
1459 			break;
1460 		}
1461 
1462 		if (!verify_imsg_src(client, proc, &imsg)) {
1463 			log_debug("dropping imsg type %d from PID %d",
1464 			    imsg.hdr.type, proc->pid);
1465 			imsg_free(&imsg);
1466 			continue;
1467 		}
1468 		if (err)
1469 			log_warnx("uid %d: %s", client->euid, err->msg);
1470 
1471 		if (do_start_repo_child) {
1472 			struct gotd_repo *repo;
1473 			const char *name = client->session->repo_name;
1474 
1475 			repo = gotd_find_repo_by_name(name, &gotd.repos);
1476 			if (repo != NULL) {
1477 				enum gotd_procid proc_type;
1478 
1479 				if (client->required_auth & GOTD_AUTH_WRITE)
1480 					proc_type = PROC_REPO_WRITE;
1481 				else
1482 					proc_type = PROC_REPO_READ;
1483 
1484 				err = start_repo_child(client, proc_type, repo,
1485 				    gotd.argv0, gotd.confpath, gotd.daemonize,
1486 				    gotd.verbosity);
1487 			} else
1488 				err = got_error(GOT_ERR_NOT_GIT_REPO);
1489 
1490 			if (err) {
1491 				log_warnx("uid %d: %s", client->euid, err->msg);
1492 				do_disconnect = 1;
1493 			}
1494 		}
1495 
1496 		if (do_disconnect) {
1497 			if (err)
1498 				disconnect_on_error(client, err);
1499 			else
1500 				disconnect(client);
1501 		}
1502 
1503 		imsg_free(&imsg);
1504 	}
1505 done:
1506 	if (!shut) {
1507 		gotd_imsg_event_add(iev);
1508 	} else {
1509 		/* This pipe is dead. Remove its event handler */
1510 		event_del(&iev->ev);
1511 		disconnect(client);
1512 	}
1513 }
1514 
1515 static const struct got_error *
1516 connect_notifier_and_session(struct gotd_client *client)
1517 {
1518 	const struct got_error *err = NULL;
1519 	struct gotd_imsgev *session_iev = &client->session->iev;
1520 	int pipe[2];
1521 	int sock_flags = SOCK_STREAM|SOCK_NONBLOCK;
1522 
1523 	if (gotd.notify_proc == NULL)
1524 		return NULL;
1525 
1526 #ifdef SOCK_CLOEXEC
1527 	sock_flags |= SOCK_CLOEXEC;
1528 #endif
1529 	if (socketpair(AF_UNIX, sock_flags,
1530 	    PF_UNSPEC, pipe) == -1)
1531 		return got_error_from_errno("socketpair");
1532 
1533 	/* Pass notifier pipe to session . */
1534 	if (gotd_imsg_compose_event(session_iev, GOTD_IMSG_CONNECT_NOTIFIER,
1535 	    PROC_GOTD, pipe[0], NULL, 0) == -1) {
1536 		err = got_error_from_errno("imsg compose CONNECT_NOTIFIER");
1537 		close(pipe[0]);
1538 		close(pipe[1]);
1539 		return err;
1540 	}
1541 
1542 	/* Pass session pipe to notifier. */
1543 	if (gotd_imsg_compose_event(&gotd.notify_proc->iev,
1544 	    GOTD_IMSG_CONNECT_SESSION, PROC_GOTD, pipe[1], NULL, 0) == -1) {
1545 		err = got_error_from_errno("imsg compose CONNECT_SESSION");
1546 		close(pipe[1]);
1547 		return err;
1548 	}
1549 
1550 	return NULL;
1551 }
1552 
1553 static void
1554 gotd_dispatch_repo_child(int fd, short event, void *arg)
1555 {
1556 	struct gotd_imsgev *iev = arg;
1557 	struct imsgbuf *ibuf = &iev->ibuf;
1558 	struct gotd_child_proc *proc = NULL;
1559 	struct gotd_client *client;
1560 	ssize_t n;
1561 	int shut = 0;
1562 	struct imsg imsg;
1563 
1564 	client = find_client_by_proc_fd(fd);
1565 	if (client == NULL) {
1566 		/* Can happen during process teardown. */
1567 		warnx("cannot find client for fd %d", fd);
1568 		shut = 1;
1569 		goto done;
1570 	}
1571 
1572 	if (event & EV_READ) {
1573 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
1574 			fatal("imsg_read error");
1575 		if (n == 0) {
1576 			/* Connection closed. */
1577 			shut = 1;
1578 			goto done;
1579 		}
1580 	}
1581 
1582 	if (event & EV_WRITE) {
1583 		n = msgbuf_write(&ibuf->w);
1584 		if (n == -1 && errno != EAGAIN)
1585 			fatal("msgbuf_write");
1586 		if (n == 0) {
1587 			/* Connection closed. */
1588 			shut = 1;
1589 			goto done;
1590 		}
1591 	}
1592 
1593 	proc = client->repo;
1594 	if (proc == NULL)
1595 		fatalx("cannot find child process for fd %d", fd);
1596 
1597 	for (;;) {
1598 		const struct got_error *err = NULL;
1599 		uint32_t client_id = 0;
1600 		int do_disconnect = 0;
1601 
1602 		if ((n = imsg_get(ibuf, &imsg)) == -1)
1603 			fatal("%s: imsg_get error", __func__);
1604 		if (n == 0)	/* No more messages. */
1605 			break;
1606 
1607 		switch (imsg.hdr.type) {
1608 		case GOTD_IMSG_ERROR:
1609 			do_disconnect = 1;
1610 			err = gotd_imsg_recv_error(&client_id, &imsg);
1611 			break;
1612 		case GOTD_IMSG_REPO_CHILD_READY:
1613 			err = connect_session(client);
1614 			if (err)
1615 				break;
1616 			err = connect_notifier_and_session(client);
1617 			if (err)
1618 				break;
1619 			err = connect_repo_child(client, proc);
1620 			break;
1621 		default:
1622 			log_debug("unexpected imsg %d", imsg.hdr.type);
1623 			break;
1624 		}
1625 
1626 		if (!verify_imsg_src(client, proc, &imsg)) {
1627 			log_debug("dropping imsg type %d from PID %d",
1628 			    imsg.hdr.type, proc->pid);
1629 			imsg_free(&imsg);
1630 			continue;
1631 		}
1632 		if (err)
1633 			log_warnx("uid %d: %s", client->euid, err->msg);
1634 
1635 		if (do_disconnect) {
1636 			if (err)
1637 				disconnect_on_error(client, err);
1638 			else
1639 				disconnect(client);
1640 		}
1641 
1642 		imsg_free(&imsg);
1643 	}
1644 done:
1645 	if (!shut) {
1646 		gotd_imsg_event_add(iev);
1647 	} else {
1648 		/* This pipe is dead. Remove its event handler */
1649 		event_del(&iev->ev);
1650 		disconnect(client);
1651 	}
1652 }
1653 
1654 static pid_t
1655 start_child(enum gotd_procid proc_id, const char *repo_path,
1656     char *argv0, const char *confpath, int fd, int daemonize, int verbosity)
1657 {
1658 	char	*argv[11];
1659 	int	 argc = 0;
1660 	pid_t	 pid;
1661 
1662 	switch (pid = fork()) {
1663 	case -1:
1664 		fatal("cannot fork");
1665 	case 0:
1666 		break;
1667 	default:
1668 		close(fd);
1669 		return pid;
1670 	}
1671 
1672 	if (fd != GOTD_FILENO_MSG_PIPE) {
1673 		if (dup2(fd, GOTD_FILENO_MSG_PIPE) == -1)
1674 			fatal("cannot setup imsg fd");
1675 	} else if (fcntl(fd, F_SETFD, 0) == -1)
1676 		fatal("cannot setup imsg fd");
1677 
1678 	argv[argc++] = argv0;
1679 	switch (proc_id) {
1680 	case PROC_LISTEN:
1681 		argv[argc++] = (char *)"-L";
1682 		break;
1683 	case PROC_AUTH:
1684 		argv[argc++] = (char *)"-A";
1685 		break;
1686 	case PROC_SESSION_READ:
1687 		argv[argc++] = (char *)"-s";
1688 		break;
1689 	case PROC_SESSION_WRITE:
1690 		argv[argc++] = (char *)"-S";
1691 		break;
1692 	case PROC_REPO_READ:
1693 		argv[argc++] = (char *)"-R";
1694 		break;
1695 	case PROC_REPO_WRITE:
1696 		argv[argc++] = (char *)"-W";
1697 		break;
1698 	case PROC_NOTIFY:
1699 		argv[argc++] = (char *)"-N";
1700 		break;
1701 	default:
1702 		fatalx("invalid process id %d", proc_id);
1703 	}
1704 
1705 	argv[argc++] = (char *)"-f";
1706 	argv[argc++] = (char *)confpath;
1707 
1708 	if (repo_path) {
1709 		argv[argc++] = (char *)"-P";
1710 		argv[argc++] = (char *)repo_path;
1711 	}
1712 
1713 	if (!daemonize)
1714 		argv[argc++] = (char *)"-d";
1715 	if (verbosity > 0)
1716 		argv[argc++] = (char *)"-v";
1717 	if (verbosity > 1)
1718 		argv[argc++] = (char *)"-v";
1719 	argv[argc++] = NULL;
1720 
1721 	execvp(argv0, argv);
1722 	fatal("execvp");
1723 }
1724 
1725 static void
1726 start_listener(char *argv0, const char *confpath, int daemonize, int verbosity)
1727 {
1728 	struct gotd_child_proc *proc;
1729 	int sock_flags = SOCK_STREAM|SOCK_NONBLOCK;
1730 
1731 #ifdef SOCK_CLOEXEC
1732 	sock_flags |= SOCK_CLOEXEC;
1733 #endif
1734 
1735 	proc = calloc(1, sizeof(*proc));
1736 	if (proc == NULL)
1737 		fatal("calloc");
1738 
1739 	TAILQ_INSERT_HEAD(&procs, proc, entry);
1740 
1741 	/* proc->tmo is initialized in main() after event_init() */
1742 
1743 	proc->type = PROC_LISTEN;
1744 
1745 	if (socketpair(AF_UNIX, sock_flags,
1746 	    PF_UNSPEC, proc->pipe) == -1)
1747 		fatal("socketpair");
1748 
1749 	proc->pid = start_child(proc->type, NULL, argv0, confpath,
1750 	    proc->pipe[1], daemonize, verbosity);
1751 	imsg_init(&proc->iev.ibuf, proc->pipe[0]);
1752 	proc->iev.handler = gotd_dispatch_listener;
1753 	proc->iev.events = EV_READ;
1754 	proc->iev.handler_arg = NULL;
1755 
1756 	gotd.listen_proc = proc;
1757 }
1758 
1759 static void
1760 start_notifier(char *argv0, const char *confpath, int daemonize, int verbosity)
1761 {
1762 	struct gotd_child_proc *proc;
1763 	int sock_flags = SOCK_STREAM | SOCK_NONBLOCK;
1764 
1765 
1766 	proc = calloc(1, sizeof(*proc));
1767 	if (proc == NULL)
1768 		fatal("calloc");
1769 
1770 	TAILQ_INSERT_HEAD(&procs, proc, entry);
1771 
1772 	/* proc->tmo is initialized in main() after event_init() */
1773 
1774 	proc->type = PROC_NOTIFY;
1775 
1776 #ifdef SOCK_CLOEXEC
1777 	sock_flags |= SOCK_CLOEXEC;
1778 #endif
1779 	if (socketpair(AF_UNIX, sock_flags,
1780 	    PF_UNSPEC, proc->pipe) == -1)
1781 		fatal("socketpair");
1782 
1783 	proc->pid = start_child(proc->type, NULL, argv0, confpath,
1784 	    proc->pipe[1], daemonize, verbosity);
1785 	imsg_init(&proc->iev.ibuf, proc->pipe[0]);
1786 	proc->iev.handler = gotd_dispatch_notifier;
1787 	proc->iev.events = EV_READ;
1788 	proc->iev.handler_arg = NULL;
1789 	event_set(&proc->iev.ev, proc->iev.ibuf.fd, EV_READ,
1790 	    gotd_dispatch_notifier, &proc->iev);
1791 
1792 	gotd.notify_proc = proc;
1793 }
1794 
1795 static const struct got_error *
1796 start_session_child(struct gotd_client *client, struct gotd_repo *repo,
1797     char *argv0, const char *confpath, int daemonize, int verbosity)
1798 {
1799 	struct gotd_child_proc *proc;
1800 	int sock_flags = SOCK_STREAM | SOCK_NONBLOCK;
1801 
1802 #ifdef SOCK_CLOEXEC
1803 	sock_flags |= SOCK_CLOEXEC;
1804 #endif
1805 
1806 	proc = calloc(1, sizeof(*proc));
1807 	if (proc == NULL)
1808 		return got_error_from_errno("calloc");
1809 
1810 	TAILQ_INSERT_HEAD(&procs, proc, entry);
1811 	evtimer_set(&proc->tmo, kill_proc_timeout, proc);
1812 
1813 	if (client_is_reading(client))
1814 		proc->type = PROC_SESSION_READ;
1815 	else
1816 		proc->type = PROC_SESSION_WRITE;
1817 	if (strlcpy(proc->repo_name, repo->name,
1818 	    sizeof(proc->repo_name)) >= sizeof(proc->repo_name))
1819 		fatalx("repository name too long: %s", repo->name);
1820 	log_debug("starting client uid %d session for repository %s",
1821 	    client->euid, repo->name);
1822 	if (strlcpy(proc->repo_path, repo->path, sizeof(proc->repo_path)) >=
1823 	    sizeof(proc->repo_path))
1824 		fatalx("repository path too long: %s", repo->path);
1825 	if (socketpair(AF_UNIX, sock_flags, PF_UNSPEC, proc->pipe) == -1)
1826 		fatal("socketpair");
1827 	proc->pid = start_child(proc->type, proc->repo_path, argv0,
1828 	    confpath, proc->pipe[1], daemonize, verbosity);
1829 	imsg_init(&proc->iev.ibuf, proc->pipe[0]);
1830 	log_debug("proc %s %s is on fd %d",
1831 	    gotd_proc_names[proc->type], proc->repo_path,
1832 	    proc->pipe[0]);
1833 	proc->iev.handler = gotd_dispatch_client_session;
1834 	proc->iev.events = EV_READ;
1835 	proc->iev.handler_arg = NULL;
1836 	event_set(&proc->iev.ev, proc->iev.ibuf.fd, EV_READ,
1837 	    gotd_dispatch_client_session, &proc->iev);
1838 	gotd_imsg_event_add(&proc->iev);
1839 
1840 	client->session = proc;
1841 	return NULL;
1842 }
1843 
1844 static const struct got_error *
1845 start_repo_child(struct gotd_client *client, enum gotd_procid proc_type,
1846     struct gotd_repo *repo, char *argv0, const char *confpath,
1847     int daemonize, int verbosity)
1848 {
1849 	struct gotd_child_proc *proc;
1850 	int sock_flags = SOCK_STREAM|SOCK_NONBLOCK;
1851 
1852 #ifdef SOCK_CLOEXEC
1853 	sock_flags |= SOCK_CLOEXEC;
1854 #endif
1855 
1856 	if (proc_type != PROC_REPO_READ && proc_type != PROC_REPO_WRITE)
1857 		return got_error_msg(GOT_ERR_NOT_IMPL, "bad process type");
1858 
1859 	proc = calloc(1, sizeof(*proc));
1860 	if (proc == NULL)
1861 		return got_error_from_errno("calloc");
1862 
1863 	TAILQ_INSERT_HEAD(&procs, proc, entry);
1864 	evtimer_set(&proc->tmo, kill_proc_timeout, proc);
1865 
1866 	proc->type = proc_type;
1867 	if (strlcpy(proc->repo_name, repo->name,
1868 	    sizeof(proc->repo_name)) >= sizeof(proc->repo_name))
1869 		fatalx("repository name too long: %s", repo->name);
1870 	log_debug("starting %s for repository %s",
1871 	    proc->type == PROC_REPO_READ ? "reader" : "writer", repo->name);
1872 
1873 	if (strlcpy(proc->repo_path, repo->path, sizeof(proc->repo_path)) >=
1874 	    sizeof(proc->repo_path))
1875 		fatalx("repository path too long: %s", repo->path);
1876 	if (realpath(repo->path, proc->repo_path) == NULL)
1877 		fatal("%s", repo->path);
1878 	if (socketpair(AF_UNIX, sock_flags,
1879 	    PF_UNSPEC, proc->pipe) == -1)
1880 		fatal("socketpair");
1881 	proc->pid = start_child(proc->type, proc->repo_path, argv0,
1882 	    confpath, proc->pipe[1], daemonize, verbosity);
1883 	imsg_init(&proc->iev.ibuf, proc->pipe[0]);
1884 	log_debug("proc %s %s is on fd %d",
1885 	    gotd_proc_names[proc->type], proc->repo_path,
1886 	    proc->pipe[0]);
1887 	proc->iev.handler = gotd_dispatch_repo_child;
1888 	proc->iev.events = EV_READ;
1889 	proc->iev.handler_arg = NULL;
1890 	event_set(&proc->iev.ev, proc->iev.ibuf.fd, EV_READ,
1891 	    gotd_dispatch_repo_child, &proc->iev);
1892 	gotd_imsg_event_add(&proc->iev);
1893 
1894 	client->repo = proc;
1895 	return NULL;
1896 }
1897 
1898 static const struct got_error *
1899 start_auth_child(struct gotd_client *client, int required_auth,
1900     struct gotd_repo *repo, char *argv0, const char *confpath,
1901     int daemonize, int verbosity)
1902 {
1903 	const struct got_error *err = NULL;
1904 	struct gotd_child_proc *proc;
1905 	struct gotd_imsg_auth iauth;
1906 	int fd;
1907 	int sock_flags = SOCK_STREAM|SOCK_NONBLOCK;
1908 
1909 #ifdef SOCK_CLOEXEC
1910 	sock_flags |= SOCK_CLOEXEC;
1911 #endif
1912 
1913 	memset(&iauth, 0, sizeof(iauth));
1914 
1915 	fd = dup(client->fd);
1916 	if (fd == -1)
1917 		return got_error_from_errno("dup");
1918 
1919 	proc = calloc(1, sizeof(*proc));
1920 	if (proc == NULL) {
1921 		err = got_error_from_errno("calloc");
1922 		close(fd);
1923 		return err;
1924 	}
1925 
1926 	TAILQ_INSERT_HEAD(&procs, proc, entry);
1927 	evtimer_set(&proc->tmo, kill_proc_timeout, proc);
1928 
1929 	proc->type = PROC_AUTH;
1930 	if (strlcpy(proc->repo_name, repo->name,
1931 	    sizeof(proc->repo_name)) >= sizeof(proc->repo_name))
1932 		fatalx("repository name too long: %s", repo->name);
1933 	log_debug("starting auth for uid %d repository %s",
1934 	    client->euid, repo->name);
1935 	if (strlcpy(proc->repo_path, repo->path, sizeof(proc->repo_path)) >=
1936 	    sizeof(proc->repo_path))
1937 		fatalx("repository path too long: %s", repo->path);
1938 	if (realpath(repo->path, proc->repo_path) == NULL)
1939 		fatal("%s", repo->path);
1940 	if (socketpair(AF_UNIX, sock_flags,
1941 	    PF_UNSPEC, proc->pipe) == -1)
1942 		fatal("socketpair");
1943 	proc->pid = start_child(proc->type, proc->repo_path, argv0,
1944 	    confpath, proc->pipe[1], daemonize, verbosity);
1945 	imsg_init(&proc->iev.ibuf, proc->pipe[0]);
1946 	log_debug("proc %s %s is on fd %d",
1947 	    gotd_proc_names[proc->type], proc->repo_path,
1948 	    proc->pipe[0]);
1949 	proc->iev.handler = gotd_dispatch_auth_child;
1950 	proc->iev.events = EV_READ;
1951 	proc->iev.handler_arg = NULL;
1952 	event_set(&proc->iev.ev, proc->iev.ibuf.fd, EV_READ,
1953 	    gotd_dispatch_auth_child, &proc->iev);
1954 	gotd_imsg_event_add(&proc->iev);
1955 
1956 	iauth.euid = client->euid;
1957 	iauth.egid = client->egid;
1958 	iauth.required_auth = required_auth;
1959 	iauth.client_id = client->id;
1960 	if (gotd_imsg_compose_event(&proc->iev, GOTD_IMSG_AUTHENTICATE,
1961 	    PROC_GOTD, fd, &iauth, sizeof(iauth)) == -1) {
1962 		log_warn("imsg compose AUTHENTICATE");
1963 		close(fd);
1964 		/* Let the auth_timeout handler tidy up. */
1965 	}
1966 
1967 	client->auth = proc;
1968 	client->required_auth = required_auth;
1969 	return NULL;
1970 }
1971 
1972 static void
1973 apply_unveil_repo_readonly(const char *repo_path, int need_tmpdir)
1974 {
1975 	if (need_tmpdir) {
1976 		if (unveil(GOT_TMPDIR_STR, "rwc") == -1)
1977 			fatal("unveil %s", GOT_TMPDIR_STR);
1978 	}
1979 
1980 	if (unveil(repo_path, "r") == -1)
1981 		fatal("unveil %s", repo_path);
1982 
1983 	if (unveil(NULL, NULL) == -1)
1984 		fatal("unveil");
1985 }
1986 
1987 static void
1988 apply_unveil_repo_readwrite(const char *repo_path)
1989 {
1990 	if (unveil(repo_path, "rwc") == -1)
1991 		fatal("unveil %s", repo_path);
1992 
1993 	if (unveil(GOT_TMPDIR_STR, "rwc") == -1)
1994 		fatal("unveil %s", GOT_TMPDIR_STR);
1995 
1996 	if (unveil(NULL, NULL) == -1)
1997 		fatal("unveil");
1998 }
1999 
2000 static void
2001 apply_unveil_none(void)
2002 {
2003 	if (unveil("/", "") == -1)
2004 		fatal("unveil");
2005 
2006 	if (unveil(NULL, NULL) == -1)
2007 		fatal("unveil");
2008 }
2009 
2010 static void
2011 apply_unveil_selfexec(void)
2012 {
2013 	if (unveil(gotd.argv0, "x") == -1)
2014 		fatal("unveil %s", gotd.argv0);
2015 
2016 	if (unveil(NULL, NULL) == -1)
2017 		fatal("unveil");
2018 }
2019 
2020 static void
2021 set_max_datasize(void)
2022 {
2023 	struct rlimit rl;
2024 
2025 	if (getrlimit(RLIMIT_DATA, &rl) != 0)
2026 		return;
2027 
2028 	rl.rlim_cur = rl.rlim_max;
2029 	setrlimit(RLIMIT_DATA, &rl);
2030 }
2031 
2032 static void
2033 unveil_notification_helpers(void)
2034 {
2035 	const char *helpers[] = {
2036 	    GOTD_PATH_PROG_NOTIFY_EMAIL,
2037 	    GOTD_PATH_PROG_NOTIFY_HTTP,
2038 	};
2039 	size_t i;
2040 
2041 	for (i = 0; i < nitems(helpers); i++) {
2042 		if (unveil(helpers[i], "x") == 0)
2043 			continue;
2044 		fatal("unveil %s", helpers[i]);
2045 	}
2046 
2047 	if (unveil(NULL, NULL) == -1)
2048 		fatal("unveil");
2049 }
2050 
2051 int
2052 main(int argc, char **argv)
2053 {
2054 	const struct got_error *error = NULL;
2055 	int ch, fd = -1, daemonize = 1, verbosity = 0, noaction = 0;
2056 	const char *confpath = GOTD_CONF_PATH;
2057 	char *argv0 = argv[0];
2058 	char title[2048];
2059 	struct passwd *pw = NULL;
2060 	char *repo_path = NULL;
2061 	enum gotd_procid proc_id = PROC_GOTD;
2062 	struct event evsigint, evsigterm, evsighup, evsigusr1, evsigchld;
2063 	int *pack_fds = NULL, *temp_fds = NULL;
2064 	struct gotd_repo *repo = NULL;
2065 	char *default_sender = NULL;
2066 	char hostname[_POSIX_HOST_NAME_MAX + 1];
2067 	FILE *diff_f1 = NULL, *diff_f2 = NULL;
2068 	int diff_fd1 = -1, diff_fd2 = -1;
2069 
2070 	TAILQ_INIT(&procs);
2071 
2072 	log_init(1, LOG_DAEMON); /* Log to stderr until daemonized. */
2073 
2074 	while ((ch = getopt(argc, argv, "Adf:LnNP:RsSvW")) != -1) {
2075 		switch (ch) {
2076 		case 'A':
2077 			proc_id = PROC_AUTH;
2078 			break;
2079 		case 'd':
2080 			daemonize = 0;
2081 			break;
2082 		case 'f':
2083 			confpath = optarg;
2084 			break;
2085 		case 'L':
2086 			proc_id = PROC_LISTEN;
2087 			break;
2088 		case 'n':
2089 			noaction = 1;
2090 			break;
2091 		case 'N':
2092 			proc_id = PROC_NOTIFY;
2093 			break;
2094 		case 'P':
2095 			repo_path = realpath(optarg, NULL);
2096 			if (repo_path == NULL)
2097 				fatal("realpath '%s'", optarg);
2098 			break;
2099 		case 'R':
2100 			proc_id = PROC_REPO_READ;
2101 			break;
2102 		case 's':
2103 			proc_id = PROC_SESSION_READ;
2104 			break;
2105 		case 'S':
2106 			proc_id = PROC_SESSION_WRITE;
2107 			break;
2108 		case 'v':
2109 			if (verbosity < 3)
2110 				verbosity++;
2111 			break;
2112 		case 'W':
2113 			proc_id = PROC_REPO_WRITE;
2114 			break;
2115 		default:
2116 			usage();
2117 		}
2118 	}
2119 
2120 	argc -= optind;
2121 	argv += optind;
2122 
2123 	if (argc != 0)
2124 		usage();
2125 
2126 	if (geteuid() && (proc_id == PROC_GOTD || proc_id == PROC_LISTEN))
2127 		fatalx("need root privileges");
2128 
2129 	if (parse_config(confpath, proc_id, &gotd) != 0)
2130 		return 1;
2131 
2132 	pw = getpwnam(gotd.user_name);
2133 	if (pw == NULL)
2134 		fatalx("user %s not found", gotd.user_name);
2135 
2136 	if (pw->pw_uid == 0)
2137 		fatalx("cannot run %s as the superuser", getprogname());
2138 
2139 	if (noaction) {
2140 		fprintf(stderr, "configuration OK\n");
2141 		return 0;
2142 	}
2143 
2144 	gotd.argv0 = argv0;
2145 	gotd.daemonize = daemonize;
2146 	gotd.verbosity = verbosity;
2147 	gotd.confpath = confpath;
2148 
2149 	/* Require an absolute path in argv[0] for reliable re-exec. */
2150 	if (!got_path_is_absolute(argv0))
2151 		fatalx("bad path \"%s\": must be an absolute path", argv0);
2152 
2153 	log_init(daemonize ? 0 : 1, LOG_DAEMON);
2154 	log_setverbose(verbosity);
2155 
2156 	if (proc_id == PROC_GOTD) {
2157 		snprintf(title, sizeof(title), "%s", gotd_proc_names[proc_id]);
2158 		arc4random_buf(&clients_hash_key, sizeof(clients_hash_key));
2159 		if (daemonize && daemon(1, 0) == -1)
2160 			fatal("daemon");
2161 		gotd.pid = getpid();
2162 		start_listener(argv0, confpath, daemonize, verbosity);
2163 		start_notifier(argv0, confpath, daemonize, verbosity);
2164 	} else if (proc_id == PROC_LISTEN) {
2165 		snprintf(title, sizeof(title), "%s", gotd_proc_names[proc_id]);
2166 		if (verbosity) {
2167 			log_info("socket: %s", gotd.unix_socket_path);
2168 			log_info("user: %s", pw->pw_name);
2169 		}
2170 
2171 		fd = unix_socket_listen(gotd.unix_socket_path, pw->pw_uid,
2172 		    pw->pw_gid);
2173 		if (fd == -1) {
2174 			fatal("cannot listen on unix socket %s",
2175 			    gotd.unix_socket_path);
2176 		}
2177 	} else if (proc_id == PROC_AUTH) {
2178 		snprintf(title, sizeof(title), "%s %s",
2179 		    gotd_proc_names[proc_id], repo_path);
2180 	} else if (proc_id == PROC_REPO_READ || proc_id == PROC_REPO_WRITE ||
2181 	    proc_id == PROC_SESSION_READ || proc_id == PROC_SESSION_WRITE) {
2182 		error = got_repo_pack_fds_open(&pack_fds);
2183 		if (error != NULL)
2184 			fatalx("cannot open pack tempfiles: %s", error->msg);
2185 		error = got_repo_temp_fds_open(&temp_fds);
2186 		if (error != NULL)
2187 			fatalx("cannot open pack tempfiles: %s", error->msg);
2188 		if (repo_path == NULL)
2189 			fatalx("repository path not specified");
2190 		snprintf(title, sizeof(title), "%s %s",
2191 		    gotd_proc_names[proc_id], repo_path);
2192 	} else if (proc_id == PROC_NOTIFY) {
2193 		snprintf(title, sizeof(title), "%s", gotd_proc_names[proc_id]);
2194 		if (gethostname(hostname, sizeof(hostname)) == -1)
2195 			fatal("gethostname");
2196 		if (asprintf(&default_sender, "%s@%s",
2197 		    pw->pw_name, hostname) == -1)
2198 			fatal("asprintf");
2199 	} else
2200 		fatal("invalid process id %d", proc_id);
2201 
2202 	setproctitle("%s", title);
2203 	log_procinit(title);
2204 
2205 	if (proc_id != PROC_GOTD && proc_id != PROC_LISTEN &&
2206 	    proc_id != PROC_REPO_READ && proc_id != PROC_REPO_WRITE) {
2207 		/* Drop root privileges. */
2208 		if (setgid(pw->pw_gid) == -1)
2209 			fatal("setgid %d failed", pw->pw_gid);
2210 		if (setuid(pw->pw_uid) == -1)
2211 			fatal("setuid %d failed", pw->pw_uid);
2212 	}
2213 
2214 	event_init();
2215 
2216 	switch (proc_id) {
2217 	case PROC_GOTD:
2218 #ifndef PROFILE
2219 		/* "exec" promise will be limited to argv[0] via unveil(2). */
2220 		if (pledge("stdio proc exec sendfd recvfd unveil", NULL) == -1)
2221 			err(1, "pledge");
2222 #endif
2223 		break;
2224 	case PROC_LISTEN:
2225 #ifndef PROFILE
2226 		if (pledge("stdio sendfd unix unveil", NULL) == -1)
2227 			err(1, "pledge");
2228 #endif
2229 		/*
2230 		 * Ensure that AF_UNIX bind(2) cannot be used with any other
2231 		 * sockets by revoking all filesystem access via unveil(2).
2232 		 */
2233 		apply_unveil_none();
2234 
2235 		enter_chroot(GOTD_EMPTY_PATH);
2236 		drop_privs(pw);
2237 
2238 		listen_main(title, fd, gotd.connection_limits,
2239 		    gotd.nconnection_limits);
2240 		/* NOTREACHED */
2241 		break;
2242 	case PROC_AUTH:
2243 #ifndef PROFILE
2244 		if (pledge("stdio getpw recvfd unix unveil", NULL) == -1)
2245 			err(1, "pledge");
2246 #endif
2247 		/*
2248 		 * We need the "unix" pledge promise for getpeername(2) only.
2249 		 * Ensure that AF_UNIX bind(2) cannot be used by revoking all
2250 		 * filesystem access via unveil(2). Access to password database
2251 		 * files will still work since "getpw" bypasses unveil(2).
2252 		 */
2253 		apply_unveil_none();
2254 
2255 		auth_main(title, &gotd.repos, repo_path);
2256 		/* NOTREACHED */
2257 		break;
2258 	case PROC_SESSION_READ:
2259 	case PROC_SESSION_WRITE:
2260 #ifndef PROFILE
2261 		/*
2262 		 * The "recvfd" promise is only needed during setup and
2263 		 * will be removed in a later pledge(2) call.
2264 		 */
2265 		if (pledge("stdio rpath wpath cpath recvfd sendfd fattr flock "
2266 		    "unveil", NULL) == -1)
2267 			err(1, "pledge");
2268 #endif
2269 		if (proc_id == PROC_SESSION_READ)
2270 			apply_unveil_repo_readonly(repo_path, 1);
2271 		else {
2272 			apply_unveil_repo_readwrite(repo_path);
2273 			repo = gotd_find_repo_by_path(repo_path, &gotd);
2274 			if (repo == NULL)
2275 				fatalx("no repository for path %s", repo_path);
2276 		}
2277 		session_main(title, repo_path, pack_fds, temp_fds,
2278 		    &gotd.request_timeout, repo, proc_id);
2279 		/* NOTREACHED */
2280 		break;
2281 	case PROC_REPO_READ:
2282 		set_max_datasize();
2283 #ifndef PROFILE
2284 		if (pledge("stdio rpath recvfd unveil", NULL) == -1)
2285 			err(1, "pledge");
2286 #endif
2287 		apply_unveil_repo_readonly(repo_path, 0);
2288 
2289 		if (enter_chroot(repo_path)) {
2290 			log_info("change repo path %s", repo_path);
2291 			free(repo_path);
2292 			repo_path = strdup("/");
2293 			if (repo_path == NULL)
2294 				fatal("strdup");
2295 			log_info("repo path is now %s", repo_path);
2296 		}
2297 		drop_privs(pw);
2298 
2299 		repo_read_main(title, repo_path, pack_fds, temp_fds);
2300 		/* NOTREACHED */
2301 		exit(0);
2302 	case PROC_REPO_WRITE:
2303 		set_max_datasize();
2304 
2305 		diff_f1 = got_opentemp();
2306 		if (diff_f1 == NULL)
2307 			fatal("got_opentemp");
2308 		diff_f2 = got_opentemp();
2309 		if (diff_f2 == NULL)
2310 			fatal("got_opentemp");
2311 		diff_fd1 = got_opentempfd();
2312 		if (diff_fd1 == -1)
2313 			fatal("got_opentempfd");
2314 		diff_fd2 = got_opentempfd();
2315 		if (diff_fd2 == -1)
2316 			fatal("got_opentempfd");
2317 #ifndef PROFILE
2318 		if (pledge("stdio rpath recvfd unveil", NULL) == -1)
2319 			err(1, "pledge");
2320 #endif
2321 		apply_unveil_repo_readonly(repo_path, 0);
2322 		repo = gotd_find_repo_by_path(repo_path, &gotd);
2323 		if (repo == NULL)
2324 			fatalx("no repository for path %s", repo_path);
2325 
2326 		if (enter_chroot(repo_path)) {
2327 			free(repo_path);
2328 			repo_path = strdup("/");
2329 			if (repo_path == NULL)
2330 				fatal("strdup");
2331 		}
2332 		drop_privs(pw);
2333 
2334 		repo_write_main(title, repo_path, pack_fds, temp_fds,
2335 		    diff_f1, diff_f2, diff_fd1, diff_fd2,
2336 		    &repo->protected_tag_namespaces,
2337 		    &repo->protected_branch_namespaces,
2338 		    &repo->protected_branches);
2339 		/* NOTREACHED */
2340 		exit(0);
2341 	case PROC_NOTIFY:
2342 #ifndef PROFILE
2343 		if (pledge("stdio proc exec recvfd unveil", NULL) == -1)
2344 			err(1, "pledge");
2345 #endif
2346 		/*
2347 		 * Limit "exec" promise to notification helpers via unveil(2).
2348 		 */
2349 		unveil_notification_helpers();
2350 
2351 		notify_main(title, &gotd.repos, default_sender);
2352 		/* NOTREACHED */
2353 		exit(0);
2354 	default:
2355 		fatal("invalid process id %d", proc_id);
2356 	}
2357 
2358 	if (proc_id != PROC_GOTD)
2359 		fatal("invalid process id %d", proc_id);
2360 
2361 	evtimer_set(&gotd.listen_proc->tmo, kill_proc_timeout,
2362 	    gotd.listen_proc);
2363 	if (gotd.notify_proc) {
2364 		evtimer_set(&gotd.notify_proc->tmo, kill_proc_timeout,
2365 		    gotd.notify_proc);
2366 	}
2367 
2368 	apply_unveil_selfexec();
2369 
2370 	signal_set(&evsigint, SIGINT, gotd_sighdlr, NULL);
2371 	signal_set(&evsigterm, SIGTERM, gotd_sighdlr, NULL);
2372 	signal_set(&evsighup, SIGHUP, gotd_sighdlr, NULL);
2373 	signal_set(&evsigusr1, SIGUSR1, gotd_sighdlr, NULL);
2374 	signal_set(&evsigchld, SIGCHLD, gotd_sighdlr, NULL);
2375 	signal(SIGPIPE, SIG_IGN);
2376 
2377 	signal_add(&evsigint, NULL);
2378 	signal_add(&evsigterm, NULL);
2379 	signal_add(&evsighup, NULL);
2380 	signal_add(&evsigusr1, NULL);
2381 	signal_add(&evsigchld, NULL);
2382 
2383 	gotd_imsg_event_add(&gotd.listen_proc->iev);
2384 	if (gotd.notify_proc)
2385 		gotd_imsg_event_add(&gotd.notify_proc->iev);
2386 
2387 	event_dispatch();
2388 
2389 	free(repo_path);
2390 	free(default_sender);
2391 	gotd_shutdown();
2392 
2393 	return 0;
2394 }