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Date:: Fri Mar 22 09:26:57 2024 UTC
Message:: split gotd/session.c into session_read.c and session_write.c This makes it easier to tweak the read/write code paths separately.
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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_read.h"
66 #include "session_write.h"
67 #include "repo_read.h"
68 #include "repo_write.h"
69 #include "notify.h"
70 
71 #ifndef nitems
72 #define nitems(_a)	(sizeof((_a)) / sizeof((_a)[0]))
73 #endif
74 
75 enum gotd_client_state {
76 	GOTD_CLIENT_STATE_NEW,
77 	GOTD_CLIENT_STATE_ACCESS_GRANTED,
78 };
79 
80 struct gotd_child_proc {
81 	pid_t				 pid;
82 	enum gotd_procid		 type;
83 	char				 repo_name[NAME_MAX];
84 	char				 repo_path[PATH_MAX];
85 	int				 pipe[2];
86 	struct gotd_imsgev		 iev;
87 	struct event			 tmo;
88 
89 	TAILQ_ENTRY(gotd_child_proc)	 entry;
90 };
91 TAILQ_HEAD(gotd_procs, gotd_child_proc) procs;
92 
93 struct gotd_client {
94 	STAILQ_ENTRY(gotd_client)	 entry;
95 	enum gotd_client_state		 state;
96 	uint32_t			 id;
97 	int				 fd;
98 	struct gotd_imsgev		 iev;
99 	struct event			 tmo;
100 	uid_t				 euid;
101 	gid_t				 egid;
102 	char				*username;
103 	struct gotd_child_proc		*repo;
104 	struct gotd_child_proc		*auth;
105 	struct gotd_child_proc		*session;
106 	int				 required_auth;
107 };
108 STAILQ_HEAD(gotd_clients, gotd_client);
109 
110 static struct gotd_clients gotd_clients[GOTD_CLIENT_TABLE_SIZE];
111 static SIPHASH_KEY clients_hash_key;
112 volatile int client_cnt;
113 static struct timeval auth_timeout = { 5, 0 };
114 static struct gotd gotd;
115 
116 void gotd_sighdlr(int sig, short event, void *arg);
117 static void gotd_shutdown(void);
118 static const struct got_error *start_session_child(struct gotd_client *,
119     struct gotd_repo *, char *, const char *, int, int);
120 static const struct got_error *start_repo_child(struct gotd_client *,
121     enum gotd_procid, struct gotd_repo *, char *, const char *, int, int);
122 static const struct got_error *start_auth_child(struct gotd_client *, int,
123     struct gotd_repo *, char *, const char *, int, int);
124 static void kill_proc(struct gotd_child_proc *, int);
125 static void disconnect(struct gotd_client *);
126 
127 __dead static void
128 usage(void)
129 {
130 	fprintf(stderr, "usage: %s [-dnv] [-f config-file]\n", getprogname());
131 	exit(1);
132 }
133 
134 static int
135 unix_socket_listen(const char *unix_socket_path, uid_t uid, gid_t gid)
136 {
137 	struct sockaddr_un sun;
138 	int fd = -1;
139 	mode_t old_umask, mode;
140 
141 	fd = socket(AF_UNIX, SOCK_STREAM | SOCK_NONBLOCK| SOCK_CLOEXEC, 0);
142 	if (fd == -1) {
143 		log_warn("socket");
144 		return -1;
145 	}
146 
147 	sun.sun_family = AF_UNIX;
148 	if (strlcpy(sun.sun_path, unix_socket_path,
149 	    sizeof(sun.sun_path)) >= sizeof(sun.sun_path)) {
150 		log_warnx("%s: name too long", unix_socket_path);
151 		close(fd);
152 		return -1;
153 	}
154 
155 	if (unlink(unix_socket_path) == -1) {
156 		if (errno != ENOENT) {
157 			log_warn("unlink %s", unix_socket_path);
158 			close(fd);
159 			return -1;
160 		}
161 	}
162 
163 	old_umask = umask(S_IXUSR|S_IXGRP|S_IWOTH|S_IROTH|S_IXOTH);
164 	mode = S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH;
165 
166 	if (bind(fd, (struct sockaddr *)&sun, sizeof(sun)) == -1) {
167 		log_warn("bind: %s", unix_socket_path);
168 		close(fd);
169 		umask(old_umask);
170 		return -1;
171 	}
172 
173 	umask(old_umask);
174 
175 	if (chmod(unix_socket_path, mode) == -1) {
176 		log_warn("chmod %o %s", mode, unix_socket_path);
177 		close(fd);
178 		unlink(unix_socket_path);
179 		return -1;
180 	}
181 
182 	if (chown(unix_socket_path, uid, gid) == -1) {
183 		log_warn("chown %s uid=%d gid=%d", unix_socket_path, uid, gid);
184 		close(fd);
185 		unlink(unix_socket_path);
186 		return -1;
187 	}
188 
189 	if (listen(fd, GOTD_UNIX_SOCKET_BACKLOG) == -1) {
190 		log_warn("listen");
191 		close(fd);
192 		unlink(unix_socket_path);
193 		return -1;
194 	}
195 
196 	return fd;
197 }
198 
199 static uint64_t
200 client_hash(uint32_t client_id)
201 {
202 	return SipHash24(&clients_hash_key, &client_id, sizeof(client_id));
203 }
204 
205 static void
206 add_client(struct gotd_client *client)
207 {
208 	uint64_t slot = client_hash(client->id) % nitems(gotd_clients);
209 	STAILQ_INSERT_HEAD(&gotd_clients[slot], client, entry);
210 	client_cnt++;
211 }
212 
213 static struct gotd_client *
214 find_client(uint32_t client_id)
215 {
216 	uint64_t slot;
217 	struct gotd_client *c;
218 
219 	slot = client_hash(client_id) % nitems(gotd_clients);
220 	STAILQ_FOREACH(c, &gotd_clients[slot], entry) {
221 		if (c->id == client_id)
222 			return c;
223 	}
224 
225 	return NULL;
226 }
227 
228 static struct gotd_client *
229 find_client_by_proc_fd(int fd)
230 {
231 	uint64_t slot;
232 
233 	for (slot = 0; slot < nitems(gotd_clients); slot++) {
234 		struct gotd_client *c;
235 
236 		STAILQ_FOREACH(c, &gotd_clients[slot], entry) {
237 			if (c->repo && c->repo->iev.ibuf.fd == fd)
238 				return c;
239 			if (c->auth && c->auth->iev.ibuf.fd == fd)
240 				return c;
241 			if (c->session && c->session->iev.ibuf.fd == fd)
242 				return c;
243 		}
244 	}
245 
246 	return NULL;
247 }
248 
249 static int
250 client_is_reading(struct gotd_client *client)
251 {
252 	return (client->required_auth &
253 	    (GOTD_AUTH_READ | GOTD_AUTH_WRITE)) == GOTD_AUTH_READ;
254 }
255 
256 static int
257 client_is_writing(struct gotd_client *client)
258 {
259 	return (client->required_auth &
260 	    (GOTD_AUTH_READ | GOTD_AUTH_WRITE)) ==
261 	    (GOTD_AUTH_READ | GOTD_AUTH_WRITE);
262 }
263 
264 static const struct got_error *
265 ensure_client_is_not_writing(struct gotd_client *client)
266 {
267 	if (client_is_writing(client)) {
268 		return got_error_fmt(GOT_ERR_BAD_PACKET,
269 		    "uid %d made a read-request but is writing to "
270 		    "a repository", client->euid);
271 	}
272 
273 	return NULL;
274 }
275 
276 static const struct got_error *
277 ensure_client_is_not_reading(struct gotd_client *client)
278 {
279 	if (client_is_reading(client)) {
280 		return got_error_fmt(GOT_ERR_BAD_PACKET,
281 		    "uid %d made a write-request but is reading from "
282 		    "a repository", client->euid);
283 	}
284 
285 	return NULL;
286 }
287 
288 static void
289 proc_done(struct gotd_child_proc *proc)
290 {
291 	struct gotd_client *client;
292 
293 	TAILQ_REMOVE(&procs, proc, entry);
294 
295 	client = find_client_by_proc_fd(proc->iev.ibuf.fd);
296 	if (client != NULL) {
297 		if (proc == client->repo)
298 			client->repo = NULL;
299 		if (proc == client->auth)
300 			client->auth = NULL;
301 		if (proc == client->session)
302 			client->session = NULL;
303 		disconnect(client);
304 	}
305 
306 	if (proc == gotd.notify_proc)
307 		gotd.notify_proc = NULL;
308 
309 	evtimer_del(&proc->tmo);
310 
311 	if (proc->iev.ibuf.fd != -1) {
312 		event_del(&proc->iev.ev);
313 		msgbuf_clear(&proc->iev.ibuf.w);
314 		close(proc->iev.ibuf.fd);
315 	}
316 
317 	free(proc);
318 }
319 
320 static void
321 kill_repo_proc(struct gotd_client *client)
322 {
323 	if (client->repo == NULL)
324 		return;
325 
326 	kill_proc(client->repo, 0);
327 	client->repo = NULL;
328 }
329 
330 static void
331 kill_auth_proc(struct gotd_client *client)
332 {
333 	if (client->auth == NULL)
334 		return;
335 
336 	kill_proc(client->auth, 0);
337 	client->auth = NULL;
338 }
339 
340 static void
341 kill_session_proc(struct gotd_client *client)
342 {
343 	if (client->session == NULL)
344 		return;
345 
346 	kill_proc(client->session, 0);
347 	client->session = NULL;
348 }
349 
350 static void
351 disconnect(struct gotd_client *client)
352 {
353 	struct gotd_imsg_disconnect idisconnect;
354 	struct gotd_child_proc *listen_proc = gotd.listen_proc;
355 	uint64_t slot;
356 
357 	log_debug("uid %d: disconnecting", client->euid);
358 
359 	kill_auth_proc(client);
360 	kill_session_proc(client);
361 	kill_repo_proc(client);
362 
363 	idisconnect.client_id = client->id;
364 	if (gotd_imsg_compose_event(&listen_proc->iev,
365 	    GOTD_IMSG_DISCONNECT, PROC_GOTD, -1,
366 	    &idisconnect, sizeof(idisconnect)) == -1)
367 		log_warn("imsg compose DISCONNECT");
368 
369 	slot = client_hash(client->id) % nitems(gotd_clients);
370 	STAILQ_REMOVE(&gotd_clients[slot], client, gotd_client, entry);
371 	imsg_clear(&client->iev.ibuf);
372 	event_del(&client->iev.ev);
373 	evtimer_del(&client->tmo);
374 	if (client->fd != -1)
375 		close(client->fd);
376 	else if (client->iev.ibuf.fd != -1)
377 		close(client->iev.ibuf.fd);
378 	free(client->username);
379 	free(client);
380 	client_cnt--;
381 }
382 
383 static void
384 disconnect_on_error(struct gotd_client *client, const struct got_error *err)
385 {
386 	struct imsgbuf ibuf;
387 
388 	if (err->code != GOT_ERR_EOF) {
389 		log_warnx("uid %d: %s", client->euid, err->msg);
390 		if (client->fd != -1) {
391 			imsg_init(&ibuf, client->fd);
392 			gotd_imsg_send_error(&ibuf, 0, PROC_GOTD, err);
393 			imsg_clear(&ibuf);
394 		}
395 	}
396 	disconnect(client);
397 }
398 
399 static const struct got_error *
400 send_repo_info(struct gotd_imsgev *iev, struct gotd_repo *repo)
401 {
402 	const struct got_error *err = NULL;
403 	struct gotd_imsg_info_repo irepo;
404 
405 	memset(&irepo, 0, sizeof(irepo));
406 
407 	if (strlcpy(irepo.repo_name, repo->name, sizeof(irepo.repo_name))
408 	    >= sizeof(irepo.repo_name))
409 		return got_error_msg(GOT_ERR_NO_SPACE, "repo name too long");
410 	if (strlcpy(irepo.repo_path, repo->path, sizeof(irepo.repo_path))
411 	    >= sizeof(irepo.repo_path))
412 		return got_error_msg(GOT_ERR_NO_SPACE, "repo path too long");
413 
414 	if (gotd_imsg_compose_event(iev, GOTD_IMSG_INFO_REPO, PROC_GOTD, -1,
415 	    &irepo, sizeof(irepo)) == -1) {
416 		err = got_error_from_errno("imsg compose INFO_REPO");
417 		if (err)
418 			return err;
419 	}
420 
421 	return NULL;
422 }
423 
424 static const struct got_error *
425 send_client_info(struct gotd_imsgev *iev, struct gotd_client *client)
426 {
427 	const struct got_error *err = NULL;
428 	struct gotd_imsg_info_client iclient;
429 	struct gotd_child_proc *proc;
430 
431 	memset(&iclient, 0, sizeof(iclient));
432 	iclient.euid = client->euid;
433 	iclient.egid = client->egid;
434 
435 	proc = client->repo;
436 	if (proc) {
437 		if (strlcpy(iclient.repo_name, proc->repo_path,
438 		    sizeof(iclient.repo_name)) >= sizeof(iclient.repo_name)) {
439 			return got_error_msg(GOT_ERR_NO_SPACE,
440 			    "repo name too long");
441 		}
442 		if (client_is_writing(client))
443 			iclient.is_writing = 1;
444 
445 		iclient.repo_child_pid = proc->pid;
446 	}
447 
448 	if (client->session)
449 		iclient.session_child_pid = client->session->pid;
450 
451 	if (gotd_imsg_compose_event(iev, GOTD_IMSG_INFO_CLIENT, PROC_GOTD, -1,
452 	    &iclient, sizeof(iclient)) == -1) {
453 		err = got_error_from_errno("imsg compose INFO_CLIENT");
454 		if (err)
455 			return err;
456 	}
457 
458 	return NULL;
459 }
460 
461 static const struct got_error *
462 send_info(struct gotd_client *client)
463 {
464 	const struct got_error *err = NULL;
465 	struct gotd_imsg_info info;
466 	uint64_t slot;
467 	struct gotd_repo *repo;
468 
469 	if (client->euid != 0)
470 		return got_error_set_errno(EPERM, "info");
471 
472 	info.pid = gotd.pid;
473 	info.verbosity = gotd.verbosity;
474 	info.nrepos = gotd.nrepos;
475 	info.nclients = client_cnt - 1;
476 
477 	if (gotd_imsg_compose_event(&client->iev, GOTD_IMSG_INFO, PROC_GOTD, -1,
478 	    &info, sizeof(info)) == -1) {
479 		err = got_error_from_errno("imsg compose INFO");
480 		if (err)
481 			return err;
482 	}
483 
484 	TAILQ_FOREACH(repo, &gotd.repos, entry) {
485 		err = send_repo_info(&client->iev, repo);
486 		if (err)
487 			return err;
488 	}
489 
490 	for (slot = 0; slot < nitems(gotd_clients); slot++) {
491 		struct gotd_client *c;
492 		STAILQ_FOREACH(c, &gotd_clients[slot], entry) {
493 			if (c->id == client->id)
494 				continue;
495 			err = send_client_info(&client->iev, c);
496 			if (err)
497 				return err;
498 		}
499 	}
500 
501 	return NULL;
502 }
503 
504 static const struct got_error *
505 stop_gotd(struct gotd_client *client)
506 {
507 
508 	if (client->euid != 0)
509 		return got_error_set_errno(EPERM, "stop");
510 
511 	gotd_shutdown();
512 	/* NOTREACHED */
513 	return NULL;
514 }
515 
516 static const struct got_error *
517 start_client_authentication(struct gotd_client *client, struct imsg *imsg)
518 {
519 	const struct got_error *err;
520 	struct gotd_imsg_list_refs ireq;
521 	struct gotd_repo *repo = NULL;
522 	size_t datalen;
523 
524 	log_debug("list-refs request from uid %d", client->euid);
525 
526 	if (client->state != GOTD_CLIENT_STATE_NEW)
527 		return got_error_msg(GOT_ERR_BAD_REQUEST,
528 		    "unexpected list-refs request received");
529 
530 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
531 	if (datalen != sizeof(ireq))
532 		return got_error(GOT_ERR_PRIVSEP_LEN);
533 
534 	memcpy(&ireq, imsg->data, datalen);
535 
536 	if (ireq.client_is_reading) {
537 		err = ensure_client_is_not_writing(client);
538 		if (err)
539 			return err;
540 		repo = gotd_find_repo_by_name(ireq.repo_name, &gotd.repos);
541 		if (repo == NULL)
542 			return got_error(GOT_ERR_NOT_GIT_REPO);
543 		err = start_auth_child(client, GOTD_AUTH_READ, repo,
544 		    gotd.argv0, gotd.confpath, gotd.daemonize,
545 		    gotd.verbosity);
546 		if (err)
547 			return err;
548 	} else {
549 		err = ensure_client_is_not_reading(client);
550 		if (err)
551 			return err;
552 		repo = gotd_find_repo_by_name(ireq.repo_name, &gotd.repos);
553 		if (repo == NULL)
554 			return got_error(GOT_ERR_NOT_GIT_REPO);
555 		err = start_auth_child(client,
556 		    GOTD_AUTH_READ | GOTD_AUTH_WRITE,
557 		    repo, gotd.argv0, gotd.confpath, gotd.daemonize,
558 		    gotd.verbosity);
559 		if (err)
560 			return err;
561 	}
562 
563 	evtimer_add(&client->tmo, &auth_timeout);
564 
565 	/* Flow continues upon authentication success/failure or timeout. */
566 	return NULL;
567 }
568 
569 static void
570 gotd_request(int fd, short events, void *arg)
571 {
572 	struct gotd_imsgev *iev = arg;
573 	struct imsgbuf *ibuf = &iev->ibuf;
574 	struct gotd_client *client = iev->handler_arg;
575 	const struct got_error *err = NULL;
576 	struct imsg imsg;
577 	ssize_t n;
578 
579 	if (events & EV_WRITE) {
580 		while (ibuf->w.queued) {
581 			n = msgbuf_write(&ibuf->w);
582 			if (n == -1 && errno == EPIPE) {
583 				/*
584 				 * The client has closed its socket.
585 				 * This can happen when Git clients are
586 				 * done sending pack file data.
587 				 */
588 				msgbuf_clear(&ibuf->w);
589 				continue;
590 			} else if (n == -1 && errno != EAGAIN) {
591 				err = got_error_from_errno("imsg_flush");
592 				disconnect_on_error(client, err);
593 				return;
594 			}
595 			if (n == 0) {
596 				/* Connection closed. */
597 				err = got_error(GOT_ERR_EOF);
598 				disconnect_on_error(client, err);
599 				return;
600 			}
601 		}
602 
603 		/* Disconnect gotctl(8) now that messages have been sent. */
604 		if (!client_is_reading(client) && !client_is_writing(client)) {
605 			disconnect(client);
606 			return;
607 		}
608 	}
609 
610 	if ((events & EV_READ) == 0)
611 		return;
612 
613 	memset(&imsg, 0, sizeof(imsg));
614 
615 	while (err == NULL) {
616 		err = gotd_imsg_recv(&imsg, ibuf, 0);
617 		if (err) {
618 			if (err->code == GOT_ERR_PRIVSEP_READ)
619 				err = NULL;
620 			break;
621 		}
622 
623 		evtimer_del(&client->tmo);
624 
625 		switch (imsg.hdr.type) {
626 		case GOTD_IMSG_INFO:
627 			err = send_info(client);
628 			break;
629 		case GOTD_IMSG_STOP:
630 			err = stop_gotd(client);
631 			break;
632 		case GOTD_IMSG_LIST_REFS:
633 			err = start_client_authentication(client, &imsg);
634 			break;
635 		default:
636 			log_debug("unexpected imsg %d", imsg.hdr.type);
637 			err = got_error(GOT_ERR_PRIVSEP_MSG);
638 			break;
639 		}
640 
641 		imsg_free(&imsg);
642 	}
643 
644 	if (err) {
645 		disconnect_on_error(client, err);
646 	} else {
647 		gotd_imsg_event_add(&client->iev);
648 	}
649 }
650 
651 static void
652 gotd_auth_timeout(int fd, short events, void *arg)
653 {
654 	struct gotd_client *client = arg;
655 
656 	log_debug("disconnecting uid %d due to authentication timeout",
657 	    client->euid);
658 	disconnect(client);
659 }
660 
661 static const struct got_error *
662 recv_connect(uint32_t *client_id, struct imsg *imsg)
663 {
664 	const struct got_error *err = NULL;
665 	struct gotd_imsg_connect iconnect;
666 	size_t datalen;
667 	int s = -1;
668 	struct gotd_client *client = NULL;
669 
670 	*client_id = 0;
671 
672 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
673 	if (datalen != sizeof(iconnect))
674 		return got_error(GOT_ERR_PRIVSEP_LEN);
675 	memcpy(&iconnect, imsg->data, sizeof(iconnect));
676 
677 	s = imsg_get_fd(imsg);
678 	if (s == -1) {
679 		err = got_error(GOT_ERR_PRIVSEP_NO_FD);
680 		goto done;
681 	}
682 
683 	if (find_client(iconnect.client_id)) {
684 		err = got_error_msg(GOT_ERR_CLIENT_ID, "duplicate client ID");
685 		goto done;
686 	}
687 
688 	client = calloc(1, sizeof(*client));
689 	if (client == NULL) {
690 		err = got_error_from_errno("calloc");
691 		goto done;
692 	}
693 
694 	*client_id = iconnect.client_id;
695 
696 	client->state = GOTD_CLIENT_STATE_NEW;
697 	client->id = iconnect.client_id;
698 	client->fd = s;
699 	s = -1;
700 	/* The auth process will verify UID/GID for us. */
701 	client->euid = iconnect.euid;
702 	client->egid = iconnect.egid;
703 
704 	imsg_init(&client->iev.ibuf, client->fd);
705 	client->iev.handler = gotd_request;
706 	client->iev.events = EV_READ;
707 	client->iev.handler_arg = client;
708 
709 	event_set(&client->iev.ev, client->fd, EV_READ, gotd_request,
710 	    &client->iev);
711 	gotd_imsg_event_add(&client->iev);
712 
713 	evtimer_set(&client->tmo, gotd_auth_timeout, client);
714 
715 	add_client(client);
716 	log_debug("%s: new client uid %d connected on fd %d", __func__,
717 	    client->euid, client->fd);
718 done:
719 	if (err) {
720 		struct gotd_child_proc *listen_proc = gotd.listen_proc;
721 		struct gotd_imsg_disconnect idisconnect;
722 
723 		idisconnect.client_id = client->id;
724 		if (gotd_imsg_compose_event(&listen_proc->iev,
725 		    GOTD_IMSG_DISCONNECT, PROC_GOTD, -1,
726 		    &idisconnect, sizeof(idisconnect)) == -1)
727 			log_warn("imsg compose DISCONNECT");
728 
729 		if (s != -1)
730 			close(s);
731 	}
732 
733 	return err;
734 }
735 
736 static const char *gotd_proc_names[PROC_MAX] = {
737 	"parent",
738 	"listen",
739 	"auth",
740 	"session_read",
741 	"session_write",
742 	"repo_read",
743 	"repo_write",
744 	"gitwrapper",
745 	"notify"
746 };
747 
748 static void
749 kill_proc(struct gotd_child_proc *proc, int fatal)
750 {
751 	struct timeval tv = { 5, 0 };
752 
753 	log_debug("kill -%d %d", fatal ? SIGKILL : SIGTERM, proc->pid);
754 
755 	if (proc->iev.ibuf.fd != -1) {
756 		event_del(&proc->iev.ev);
757 		msgbuf_clear(&proc->iev.ibuf.w);
758 		close(proc->iev.ibuf.fd);
759 		proc->iev.ibuf.fd = -1;
760 	}
761 
762 	if (!evtimer_pending(&proc->tmo, NULL) && !fatal)
763 		evtimer_add(&proc->tmo, &tv);
764 
765 	if (fatal) {
766 		log_warnx("sending SIGKILL to PID %d", proc->pid);
767 		kill(proc->pid, SIGKILL);
768 	} else
769 		kill(proc->pid, SIGTERM);
770 }
771 
772 static void
773 kill_proc_timeout(int fd, short ev, void *d)
774 {
775 	struct gotd_child_proc *proc = d;
776 
777 	log_warnx("timeout waiting for PID %d to terminate;"
778 	    " retrying with force", proc->pid);
779 	kill_proc(proc, 1);
780 }
781 
782 static void
783 gotd_shutdown(void)
784 {
785 	uint64_t slot;
786 
787 	log_debug("shutting down");
788 	for (slot = 0; slot < nitems(gotd_clients); slot++) {
789 		struct gotd_client *c, *tmp;
790 
791 		STAILQ_FOREACH_SAFE(c, &gotd_clients[slot], entry, tmp)
792 			disconnect(c);
793 	}
794 
795 	kill_proc(gotd.listen_proc, 0);
796 
797 	log_info("terminating");
798 	exit(0);
799 }
800 
801 static struct gotd_child_proc *
802 find_proc_by_pid(pid_t pid)
803 {
804 	struct gotd_child_proc *proc = NULL;
805 
806 	TAILQ_FOREACH(proc, &procs, entry)
807 		if (proc->pid == pid)
808 			break;
809 
810 	return proc;
811 }
812 
813 void
814 gotd_sighdlr(int sig, short event, void *arg)
815 {
816 	struct gotd_child_proc *proc;
817 	pid_t pid;
818 	int status;
819 
820 	/*
821 	 * Normal signal handler rules don't apply because libevent
822 	 * decouples for us.
823 	 */
824 
825 	switch (sig) {
826 	case SIGHUP:
827 		log_info("%s: ignoring SIGHUP", __func__);
828 		break;
829 	case SIGUSR1:
830 		log_info("%s: ignoring SIGUSR1", __func__);
831 		break;
832 	case SIGTERM:
833 	case SIGINT:
834 		gotd_shutdown();
835 		break;
836 	case SIGCHLD:
837 		for (;;) {
838 			pid = waitpid(WAIT_ANY, &status, WNOHANG);
839 			if (pid == -1) {
840 				if (errno == EINTR)
841 					continue;
842 				if (errno == ECHILD)
843 					break;
844 				fatal("waitpid");
845 			}
846 			if (pid == 0)
847 				break;
848 
849 			log_debug("reaped pid %d", pid);
850 			proc = find_proc_by_pid(pid);
851 			if (proc == NULL) {
852 				log_info("caught exit of unknown child %d",
853 				    pid);
854 				continue;
855 			}
856 
857 			if (WIFSIGNALED(status)) {
858 				log_warnx("child PID %d terminated with"
859 				    " signal %d", pid, WTERMSIG(status));
860 			}
861 
862 			proc_done(proc);
863 		}
864 		break;
865 	default:
866 		fatalx("unexpected signal");
867 	}
868 }
869 
870 static const struct got_error *
871 ensure_proc_is_reading(struct gotd_client *client,
872     struct gotd_child_proc *proc)
873 {
874 	if (!client_is_reading(client)) {
875 		kill_proc(proc, 1);
876 		return got_error_fmt(GOT_ERR_BAD_PACKET,
877 		    "PID %d handled a read-request for uid %d but this "
878 		    "user is not reading from a repository", proc->pid,
879 		    client->euid);
880 	}
881 
882 	return NULL;
883 }
884 
885 static const struct got_error *
886 ensure_proc_is_writing(struct gotd_client *client,
887     struct gotd_child_proc *proc)
888 {
889 	if (!client_is_writing(client)) {
890 		kill_proc(proc, 1);
891 		return got_error_fmt(GOT_ERR_BAD_PACKET,
892 		    "PID %d handled a write-request for uid %d but this "
893 		    "user is not writing to a repository", proc->pid,
894 		    client->euid);
895 	}
896 
897 	return NULL;
898 }
899 
900 static int
901 verify_imsg_src(struct gotd_client *client, struct gotd_child_proc *proc,
902     struct imsg *imsg)
903 {
904 	const struct got_error *err;
905 	int ret = 0;
906 
907 	if (proc->type == PROC_REPO_READ || proc->type == PROC_REPO_WRITE) {
908 		if (client->repo == NULL)
909 			fatalx("no process found for uid %d", client->euid);
910 		if (proc->pid != client->repo->pid) {
911 			kill_proc(proc, 1);
912 			log_warnx("received message from PID %d for uid %d, "
913 			    "while PID %d is the process serving this user",
914 			    proc->pid, client->euid, client->repo->pid);
915 			return 0;
916 		}
917 	}
918 	if (proc->type == PROC_SESSION_READ ||
919 	    proc->type == PROC_SESSION_WRITE) {
920 		if (client->session == NULL) {
921 			log_warnx("no session found for uid %d", client->euid);
922 			return 0;
923 		}
924 		if (proc->pid != client->session->pid) {
925 			kill_proc(proc, 1);
926 			log_warnx("received message from PID %d for uid %d, "
927 			    "while PID %d is the process serving this user",
928 			    proc->pid, client->euid, client->session->pid);
929 			return 0;
930 		}
931 	}
932 
933 	switch (imsg->hdr.type) {
934 	case GOTD_IMSG_ERROR:
935 		ret = 1;
936 		break;
937 	case GOTD_IMSG_CONNECT:
938 		if (proc->type != PROC_LISTEN) {
939 			err = got_error_fmt(GOT_ERR_BAD_PACKET,
940 			    "new connection for uid %d from PID %d "
941 			    "which is not the listen process",
942 			    client->euid, proc->pid);
943 		} else
944 			ret = 1;
945 		break;
946 	case GOTD_IMSG_ACCESS_GRANTED:
947 		if (proc->type != PROC_AUTH) {
948 			err = got_error_fmt(GOT_ERR_BAD_PACKET,
949 			    "authentication of uid %d from PID %d "
950 			    "which is not the auth process",
951 			    client->euid, proc->pid);
952 		} else
953 			ret = 1;
954 		break;
955 	case GOTD_IMSG_CLIENT_SESSION_READY:
956 		if (proc->type != PROC_SESSION_READ &&
957 		    proc->type != PROC_SESSION_WRITE) {
958 			err = got_error_fmt(GOT_ERR_BAD_PACKET,
959 			    "unexpected \"ready\" signal from PID %d",
960 			    proc->pid);
961 		} else
962 			ret = 1;
963 		break;
964 	case GOTD_IMSG_REPO_CHILD_READY:
965 		if (proc->type != PROC_REPO_READ &&
966 		    proc->type != PROC_REPO_WRITE) {
967 			err = got_error_fmt(GOT_ERR_BAD_PACKET,
968 			    "unexpected \"ready\" signal from PID %d",
969 			    proc->pid);
970 		} else
971 			ret = 1;
972 		break;
973 	case GOTD_IMSG_PACKFILE_DONE:
974 		err = ensure_proc_is_reading(client, proc);
975 		if (err)
976 			log_warnx("uid %d: %s", client->euid, err->msg);
977 		else
978 			ret = 1;
979 		break;
980 	case GOTD_IMSG_PACKFILE_INSTALL:
981 	case GOTD_IMSG_REF_UPDATES_START:
982 	case GOTD_IMSG_REF_UPDATE:
983 		err = ensure_proc_is_writing(client, proc);
984 		if (err)
985 			log_warnx("uid %d: %s", client->euid, err->msg);
986 		else
987 			ret = 1;
988 		break;
989 	default:
990 		log_debug("%s: unexpected imsg %d", __func__, imsg->hdr.type);
991 		break;
992 	}
993 
994 	return ret;
995 }
996 
997 static const struct got_error *
998 connect_repo_child(struct gotd_client *client,
999     struct gotd_child_proc *repo_proc)
1000 {
1001 	static const struct got_error *err;
1002 	struct gotd_imsgev *session_iev = &client->session->iev;
1003 	struct gotd_imsg_connect_repo_child ireq;
1004 	int pipe[2];
1005 
1006 	if (client->state != GOTD_CLIENT_STATE_ACCESS_GRANTED)
1007 		return got_error_msg(GOT_ERR_BAD_REQUEST,
1008 		    "unexpected repo child ready signal received");
1009 
1010 	if (socketpair(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK,
1011 	    PF_UNSPEC, pipe) == -1)
1012 		fatal("socketpair");
1013 
1014 	memset(&ireq, 0, sizeof(ireq));
1015 	ireq.proc_id = repo_proc->type;
1016 
1017 	/* Pass repo child pipe to session child process. */
1018 	if (gotd_imsg_compose_event(session_iev, GOTD_IMSG_CONNECT_REPO_CHILD,
1019 	    PROC_GOTD, pipe[0], &ireq, sizeof(ireq)) == -1) {
1020 		err = got_error_from_errno("imsg compose CONNECT_REPO_CHILD");
1021 		close(pipe[0]);
1022 		close(pipe[1]);
1023 		return err;
1024 	}
1025 
1026 	/* Pass session child pipe to repo child process. */
1027 	if (gotd_imsg_compose_event(&repo_proc->iev,
1028 	    GOTD_IMSG_CONNECT_REPO_CHILD, PROC_GOTD, pipe[1], NULL, 0) == -1) {
1029 		err = got_error_from_errno("imsg compose CONNECT_REPO_CHILD");
1030 		close(pipe[1]);
1031 		return err;
1032 	}
1033 
1034 	return NULL;
1035 }
1036 
1037 static void
1038 gotd_dispatch_listener(int fd, short event, void *arg)
1039 {
1040 	struct gotd_imsgev *iev = arg;
1041 	struct imsgbuf *ibuf = &iev->ibuf;
1042 	struct gotd_child_proc *proc = gotd.listen_proc;
1043 	ssize_t n;
1044 	int shut = 0;
1045 	struct imsg imsg;
1046 
1047 	if (proc->iev.ibuf.fd != fd)
1048 		fatalx("%s: unexpected fd %d", __func__, fd);
1049 
1050 	if (event & EV_READ) {
1051 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
1052 			fatal("imsg_read error");
1053 		if (n == 0) {
1054 			/* Connection closed. */
1055 			shut = 1;
1056 			goto done;
1057 		}
1058 	}
1059 
1060 	if (event & EV_WRITE) {
1061 		n = msgbuf_write(&ibuf->w);
1062 		if (n == -1 && errno != EAGAIN)
1063 			fatal("msgbuf_write");
1064 		if (n == 0) {
1065 			/* Connection closed. */
1066 			shut = 1;
1067 			goto done;
1068 		}
1069 	}
1070 
1071 	for (;;) {
1072 		const struct got_error *err = NULL;
1073 		struct gotd_client *client = NULL;
1074 		uint32_t client_id = 0;
1075 		int do_disconnect = 0;
1076 
1077 		if ((n = imsg_get(ibuf, &imsg)) == -1)
1078 			fatal("%s: imsg_get error", __func__);
1079 		if (n == 0)	/* No more messages. */
1080 			break;
1081 
1082 		switch (imsg.hdr.type) {
1083 		case GOTD_IMSG_ERROR:
1084 			do_disconnect = 1;
1085 			err = gotd_imsg_recv_error(&client_id, &imsg);
1086 			break;
1087 		case GOTD_IMSG_CONNECT:
1088 			err = recv_connect(&client_id, &imsg);
1089 			break;
1090 		default:
1091 			log_debug("unexpected imsg %d", imsg.hdr.type);
1092 			break;
1093 		}
1094 
1095 		client = find_client(client_id);
1096 		if (client == NULL) {
1097 			log_warnx("%s: client not found", __func__);
1098 			imsg_free(&imsg);
1099 			continue;
1100 		}
1101 
1102 		if (err)
1103 			log_warnx("uid %d: %s", client->euid, err->msg);
1104 
1105 		if (do_disconnect) {
1106 			if (err)
1107 				disconnect_on_error(client, err);
1108 			else
1109 				disconnect(client);
1110 		}
1111 
1112 		imsg_free(&imsg);
1113 	}
1114 done:
1115 	if (!shut) {
1116 		gotd_imsg_event_add(iev);
1117 	} else {
1118 		/* This pipe is dead. Remove its event handler */
1119 		event_del(&iev->ev);
1120 		event_loopexit(NULL);
1121 	}
1122 }
1123 
1124 static void
1125 gotd_dispatch_notifier(int fd, short event, void *arg)
1126 {
1127 	struct gotd_imsgev *iev = arg;
1128 	struct imsgbuf *ibuf = &iev->ibuf;
1129 	struct gotd_child_proc *proc = gotd.notify_proc;
1130 	ssize_t n;
1131 	int shut = 0;
1132 	struct imsg imsg;
1133 
1134 	if (proc->iev.ibuf.fd != fd)
1135 		fatalx("%s: unexpected fd %d", __func__, fd);
1136 
1137 	if (event & EV_READ) {
1138 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
1139 			fatal("imsg_read error");
1140 		if (n == 0) {
1141 			/* Connection closed. */
1142 			shut = 1;
1143 			goto done;
1144 		}
1145 	}
1146 
1147 	if (event & EV_WRITE) {
1148 		n = msgbuf_write(&ibuf->w);
1149 		if (n == -1 && errno != EAGAIN)
1150 			fatal("msgbuf_write");
1151 		if (n == 0) {
1152 			/* Connection closed. */
1153 			shut = 1;
1154 			goto done;
1155 		}
1156 	}
1157 
1158 	for (;;) {
1159 		if ((n = imsg_get(ibuf, &imsg)) == -1)
1160 			fatal("%s: imsg_get error", __func__);
1161 		if (n == 0)	/* No more messages. */
1162 			break;
1163 
1164 		switch (imsg.hdr.type) {
1165 		default:
1166 			log_debug("unexpected imsg %d", imsg.hdr.type);
1167 			break;
1168 		}
1169 
1170 		imsg_free(&imsg);
1171 	}
1172 done:
1173 	if (!shut) {
1174 		gotd_imsg_event_add(iev);
1175 	} else {
1176 		/* This pipe is dead. Remove its event handler */
1177 		event_del(&iev->ev);
1178 
1179 		/*
1180 		 * Do not exit all of gotd if the notification handler dies.
1181 		 * We can continue operating without notifications until an
1182 		 * operator intervenes.
1183 		 */
1184 		log_warnx("notify child process (pid %d) closed its imsg pipe "
1185 		    "unexpectedly", proc->pid);
1186 		proc_done(proc);
1187 	}
1188 }
1189 
1190 static void
1191 gotd_dispatch_auth_child(int fd, short event, void *arg)
1192 {
1193 	const struct got_error *err = NULL;
1194 	struct gotd_imsgev *iev = arg;
1195 	struct imsgbuf *ibuf = &iev->ibuf;
1196 	struct gotd_client *client;
1197 	struct gotd_repo *repo = NULL;
1198 	ssize_t n;
1199 	int shut = 0;
1200 	struct imsg imsg;
1201 	uint32_t client_id = 0;
1202 	int do_disconnect = 0;
1203 	size_t datalen;
1204 
1205 	client = find_client_by_proc_fd(fd);
1206 	if (client == NULL) {
1207 		/* Can happen during process teardown. */
1208 		warnx("cannot find client for fd %d", fd);
1209 		shut = 1;
1210 		goto done;
1211 	}
1212 
1213 	if (client->auth == NULL)
1214 		fatalx("cannot find auth child process for fd %d", fd);
1215 
1216 	if (event & EV_READ) {
1217 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
1218 			fatal("imsg_read error");
1219 		if (n == 0) {
1220 			/* Connection closed. */
1221 			shut = 1;
1222 			goto done;
1223 		}
1224 	}
1225 
1226 	if (event & EV_WRITE) {
1227 		n = msgbuf_write(&ibuf->w);
1228 		if (n == -1 && errno != EAGAIN)
1229 			fatal("msgbuf_write");
1230 		if (n == 0) {
1231 			/* Connection closed. */
1232 			shut = 1;
1233 		}
1234 		goto done;
1235 	}
1236 
1237 	if (client->auth->iev.ibuf.fd != fd)
1238 		fatalx("%s: unexpected fd %d", __func__, fd);
1239 
1240 	if ((n = imsg_get(ibuf, &imsg)) == -1)
1241 		fatal("%s: imsg_get error", __func__);
1242 	if (n == 0)	/* No more messages. */
1243 		return;
1244 
1245 	evtimer_del(&client->tmo);
1246 
1247 	datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
1248 
1249 	switch (imsg.hdr.type) {
1250 	case GOTD_IMSG_ERROR:
1251 		do_disconnect = 1;
1252 		err = gotd_imsg_recv_error(&client_id, &imsg);
1253 		break;
1254 	case GOTD_IMSG_ACCESS_GRANTED:
1255 		if (client->state != GOTD_CLIENT_STATE_NEW) {
1256 			do_disconnect = 1;
1257 			err = got_error(GOT_ERR_PRIVSEP_MSG);
1258 		}
1259 		break;
1260 	default:
1261 		do_disconnect = 1;
1262 		log_debug("unexpected imsg %d", imsg.hdr.type);
1263 		break;
1264 	}
1265 
1266 	if (!verify_imsg_src(client, client->auth, &imsg)) {
1267 		do_disconnect = 1;
1268 		log_debug("dropping imsg type %d from PID %d",
1269 		    imsg.hdr.type, client->auth->pid);
1270 	}
1271 
1272 	if (do_disconnect) {
1273 		if (err)
1274 			disconnect_on_error(client, err);
1275 		else
1276 			disconnect(client);
1277 		imsg_free(&imsg);
1278 		return;
1279 	}
1280 
1281 	client->state = GOTD_CLIENT_STATE_ACCESS_GRANTED;
1282 	if (datalen > 0)
1283 		client->username = strndup(imsg.data, datalen);
1284 	imsg_free(&imsg);
1285 	if (client->username == NULL &&
1286 	    asprintf(&client->username, "uid %d", client->euid) == -1) {
1287 		err = got_error_from_errno("asprintf");
1288 		goto done;
1289 	}
1290 
1291 	repo = gotd_find_repo_by_name(client->auth->repo_name, &gotd.repos);
1292 	if (repo == NULL) {
1293 		err = got_error(GOT_ERR_NOT_GIT_REPO);
1294 		goto done;
1295 	}
1296 	kill_auth_proc(client);
1297 
1298 	log_info("authenticated %s for repository %s",
1299 	    client->username, repo->name);
1300 
1301 	err = start_session_child(client, repo, gotd.argv0,
1302 	    gotd.confpath, gotd.daemonize, gotd.verbosity);
1303 	if (err)
1304 		goto done;
1305 done:
1306 	if (err)
1307 		log_warnx("uid %d: %s", client->euid, err->msg);
1308 
1309 	/* We might have killed the auth process by now. */
1310 	if (client->auth != NULL) {
1311 		if (!shut) {
1312 			gotd_imsg_event_add(iev);
1313 		} else {
1314 			/* This pipe is dead. Remove its event handler */
1315 			event_del(&iev->ev);
1316 		}
1317 	}
1318 }
1319 
1320 static const struct got_error *
1321 connect_session(struct gotd_client *client)
1322 {
1323 	const struct got_error *err = NULL;
1324 	struct gotd_imsg_connect iconnect;
1325 	int s;
1326 	struct ibuf *wbuf;
1327 
1328 	memset(&iconnect, 0, sizeof(iconnect));
1329 
1330 	s = dup(client->fd);
1331 	if (s == -1)
1332 		return got_error_from_errno("dup");
1333 
1334 	iconnect.client_id = client->id;
1335 	iconnect.euid = client->euid;
1336 	iconnect.egid = client->egid;
1337 	iconnect.username_len = strlen(client->username);
1338 
1339 	wbuf = imsg_create(&client->session->iev.ibuf, GOTD_IMSG_CONNECT,
1340 	    PROC_GOTD, gotd.pid, sizeof(iconnect) + iconnect.username_len);
1341 	if (wbuf == NULL) {
1342 		err = got_error_from_errno("imsg compose CONNECT");
1343 		close(s);
1344 		return err;
1345 	}
1346 	if (imsg_add(wbuf, &iconnect, sizeof(iconnect)) == -1) {
1347 		close(s);
1348 		return got_error_from_errno("imsg_add CONNECT");
1349 	}
1350 	if (imsg_add(wbuf, client->username, iconnect.username_len) == -1) {
1351 		close(s);
1352 		return got_error_from_errno("imsg_add CONNECT");
1353 	}
1354 
1355 	ibuf_fd_set(wbuf, s);
1356 	imsg_close(&client->session->iev.ibuf, wbuf);
1357 	gotd_imsg_event_add(&client->session->iev);
1358 
1359 	/*
1360 	 * We are no longer interested in messages from this client.
1361 	 * Further client requests will be handled by the session process.
1362 	 */
1363 	msgbuf_clear(&client->iev.ibuf.w);
1364 	imsg_clear(&client->iev.ibuf);
1365 	event_del(&client->iev.ev);
1366 	client->fd = -1; /* will be closed via copy in client->iev.ibuf.fd */
1367 
1368 	return NULL;
1369 }
1370 
1371 static void
1372 gotd_dispatch_client_session(int fd, short event, void *arg)
1373 {
1374 	struct gotd_imsgev *iev = arg;
1375 	struct imsgbuf *ibuf = &iev->ibuf;
1376 	struct gotd_child_proc *proc = NULL;
1377 	struct gotd_client *client = NULL;
1378 	ssize_t n;
1379 	int shut = 0;
1380 	struct imsg imsg;
1381 
1382 	client = find_client_by_proc_fd(fd);
1383 	if (client == NULL) {
1384 		/* Can happen during process teardown. */
1385 		warnx("cannot find client for fd %d", fd);
1386 		shut = 1;
1387 		goto done;
1388 	}
1389 
1390 	if (event & EV_READ) {
1391 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
1392 			fatal("imsg_read error");
1393 		if (n == 0) {
1394 			/* Connection closed. */
1395 			shut = 1;
1396 			goto done;
1397 		}
1398 	}
1399 
1400 	if (event & EV_WRITE) {
1401 		n = msgbuf_write(&ibuf->w);
1402 		if (n == -1 && errno != EAGAIN)
1403 			fatal("msgbuf_write");
1404 		if (n == 0) {
1405 			/* Connection closed. */
1406 			shut = 1;
1407 			goto done;
1408 		}
1409 	}
1410 
1411 	proc = client->session;
1412 	if (proc == NULL)
1413 		fatalx("cannot find session child process for fd %d", fd);
1414 
1415 	for (;;) {
1416 		const struct got_error *err = NULL;
1417 		uint32_t client_id = 0;
1418 		int do_disconnect = 0, do_start_repo_child = 0;
1419 
1420 		if ((n = imsg_get(ibuf, &imsg)) == -1)
1421 			fatal("%s: imsg_get error", __func__);
1422 		if (n == 0)	/* No more messages. */
1423 			break;
1424 
1425 		switch (imsg.hdr.type) {
1426 		case GOTD_IMSG_ERROR:
1427 			do_disconnect = 1;
1428 			err = gotd_imsg_recv_error(&client_id, &imsg);
1429 			break;
1430 		case GOTD_IMSG_CLIENT_SESSION_READY:
1431 			if (client->state != GOTD_CLIENT_STATE_ACCESS_GRANTED) {
1432 				err = got_error(GOT_ERR_PRIVSEP_MSG);
1433 				break;
1434 			}
1435 			do_start_repo_child = 1;
1436 			break;
1437 		case GOTD_IMSG_DISCONNECT:
1438 			do_disconnect = 1;
1439 			break;
1440 		default:
1441 			log_debug("unexpected imsg %d", imsg.hdr.type);
1442 			break;
1443 		}
1444 
1445 		if (!verify_imsg_src(client, proc, &imsg)) {
1446 			log_debug("dropping imsg type %d from PID %d",
1447 			    imsg.hdr.type, proc->pid);
1448 			imsg_free(&imsg);
1449 			continue;
1450 		}
1451 		if (err)
1452 			log_warnx("uid %d: %s", client->euid, err->msg);
1453 
1454 		if (do_start_repo_child) {
1455 			struct gotd_repo *repo;
1456 			const char *name = client->session->repo_name;
1457 
1458 			repo = gotd_find_repo_by_name(name, &gotd.repos);
1459 			if (repo != NULL) {
1460 				enum gotd_procid proc_type;
1461 
1462 				if (client->required_auth & GOTD_AUTH_WRITE)
1463 					proc_type = PROC_REPO_WRITE;
1464 				else
1465 					proc_type = PROC_REPO_READ;
1466 
1467 				err = start_repo_child(client, proc_type, repo,
1468 				    gotd.argv0, gotd.confpath, gotd.daemonize,
1469 				    gotd.verbosity);
1470 			} else
1471 				err = got_error(GOT_ERR_NOT_GIT_REPO);
1472 
1473 			if (err) {
1474 				log_warnx("uid %d: %s", client->euid, err->msg);
1475 				do_disconnect = 1;
1476 			}
1477 		}
1478 
1479 		if (do_disconnect) {
1480 			if (err)
1481 				disconnect_on_error(client, err);
1482 			else
1483 				disconnect(client);
1484 		}
1485 
1486 		imsg_free(&imsg);
1487 	}
1488 done:
1489 	if (!shut) {
1490 		gotd_imsg_event_add(iev);
1491 	} else {
1492 		/* This pipe is dead. Remove its event handler */
1493 		event_del(&iev->ev);
1494 		disconnect(client);
1495 	}
1496 }
1497 
1498 static const struct got_error *
1499 connect_notifier_and_session(struct gotd_client *client)
1500 {
1501 	const struct got_error *err = NULL;
1502 	struct gotd_imsgev *session_iev = &client->session->iev;
1503 	int pipe[2];
1504 
1505 	if (gotd.notify_proc == NULL)
1506 		return NULL;
1507 
1508 	if (socketpair(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK,
1509 	    PF_UNSPEC, pipe) == -1)
1510 		return got_error_from_errno("socketpair");
1511 
1512 	/* Pass notifier pipe to session . */
1513 	if (gotd_imsg_compose_event(session_iev, GOTD_IMSG_CONNECT_NOTIFIER,
1514 	    PROC_GOTD, pipe[0], NULL, 0) == -1) {
1515 		err = got_error_from_errno("imsg compose CONNECT_NOTIFIER");
1516 		close(pipe[0]);
1517 		close(pipe[1]);
1518 		return err;
1519 	}
1520 
1521 	/* Pass session pipe to notifier. */
1522 	if (gotd_imsg_compose_event(&gotd.notify_proc->iev,
1523 	    GOTD_IMSG_CONNECT_SESSION, PROC_GOTD, pipe[1], NULL, 0) == -1) {
1524 		err = got_error_from_errno("imsg compose CONNECT_SESSION");
1525 		close(pipe[1]);
1526 		return err;
1527 	}
1528 
1529 	return NULL;
1530 }
1531 
1532 static void
1533 gotd_dispatch_repo_child(int fd, short event, void *arg)
1534 {
1535 	struct gotd_imsgev *iev = arg;
1536 	struct imsgbuf *ibuf = &iev->ibuf;
1537 	struct gotd_child_proc *proc = NULL;
1538 	struct gotd_client *client;
1539 	ssize_t n;
1540 	int shut = 0;
1541 	struct imsg imsg;
1542 
1543 	client = find_client_by_proc_fd(fd);
1544 	if (client == NULL) {
1545 		/* Can happen during process teardown. */
1546 		warnx("cannot find client for fd %d", fd);
1547 		shut = 1;
1548 		goto done;
1549 	}
1550 
1551 	if (event & EV_READ) {
1552 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
1553 			fatal("imsg_read error");
1554 		if (n == 0) {
1555 			/* Connection closed. */
1556 			shut = 1;
1557 			goto done;
1558 		}
1559 	}
1560 
1561 	if (event & EV_WRITE) {
1562 		n = msgbuf_write(&ibuf->w);
1563 		if (n == -1 && errno != EAGAIN)
1564 			fatal("msgbuf_write");
1565 		if (n == 0) {
1566 			/* Connection closed. */
1567 			shut = 1;
1568 			goto done;
1569 		}
1570 	}
1571 
1572 	proc = client->repo;
1573 	if (proc == NULL)
1574 		fatalx("cannot find child process for fd %d", fd);
1575 
1576 	for (;;) {
1577 		const struct got_error *err = NULL;
1578 		uint32_t client_id = 0;
1579 		int do_disconnect = 0;
1580 
1581 		if ((n = imsg_get(ibuf, &imsg)) == -1)
1582 			fatal("%s: imsg_get error", __func__);
1583 		if (n == 0)	/* No more messages. */
1584 			break;
1585 
1586 		switch (imsg.hdr.type) {
1587 		case GOTD_IMSG_ERROR:
1588 			do_disconnect = 1;
1589 			err = gotd_imsg_recv_error(&client_id, &imsg);
1590 			break;
1591 		case GOTD_IMSG_REPO_CHILD_READY:
1592 			err = connect_session(client);
1593 			if (err)
1594 				break;
1595 			err = connect_notifier_and_session(client);
1596 			if (err)
1597 				break;
1598 			err = connect_repo_child(client, proc);
1599 			break;
1600 		default:
1601 			log_debug("unexpected imsg %d", imsg.hdr.type);
1602 			break;
1603 		}
1604 
1605 		if (!verify_imsg_src(client, proc, &imsg)) {
1606 			log_debug("dropping imsg type %d from PID %d",
1607 			    imsg.hdr.type, proc->pid);
1608 			imsg_free(&imsg);
1609 			continue;
1610 		}
1611 		if (err)
1612 			log_warnx("uid %d: %s", client->euid, err->msg);
1613 
1614 		if (do_disconnect) {
1615 			if (err)
1616 				disconnect_on_error(client, err);
1617 			else
1618 				disconnect(client);
1619 		}
1620 
1621 		imsg_free(&imsg);
1622 	}
1623 done:
1624 	if (!shut) {
1625 		gotd_imsg_event_add(iev);
1626 	} else {
1627 		/* This pipe is dead. Remove its event handler */
1628 		event_del(&iev->ev);
1629 		disconnect(client);
1630 	}
1631 }
1632 
1633 static pid_t
1634 start_child(enum gotd_procid proc_id, const char *repo_path,
1635     char *argv0, const char *confpath, int fd, int daemonize, int verbosity)
1636 {
1637 	char	*argv[11];
1638 	int	 argc = 0;
1639 	pid_t	 pid;
1640 
1641 	switch (pid = fork()) {
1642 	case -1:
1643 		fatal("cannot fork");
1644 	case 0:
1645 		break;
1646 	default:
1647 		close(fd);
1648 		return pid;
1649 	}
1650 
1651 	if (fd != GOTD_FILENO_MSG_PIPE) {
1652 		if (dup2(fd, GOTD_FILENO_MSG_PIPE) == -1)
1653 			fatal("cannot setup imsg fd");
1654 	} else if (fcntl(fd, F_SETFD, 0) == -1)
1655 		fatal("cannot setup imsg fd");
1656 
1657 	argv[argc++] = argv0;
1658 	switch (proc_id) {
1659 	case PROC_LISTEN:
1660 		argv[argc++] = (char *)"-L";
1661 		break;
1662 	case PROC_AUTH:
1663 		argv[argc++] = (char *)"-A";
1664 		break;
1665 	case PROC_SESSION_READ:
1666 		argv[argc++] = (char *)"-s";
1667 		break;
1668 	case PROC_SESSION_WRITE:
1669 		argv[argc++] = (char *)"-S";
1670 		break;
1671 	case PROC_REPO_READ:
1672 		argv[argc++] = (char *)"-R";
1673 		break;
1674 	case PROC_REPO_WRITE:
1675 		argv[argc++] = (char *)"-W";
1676 		break;
1677 	case PROC_NOTIFY:
1678 		argv[argc++] = (char *)"-N";
1679 		break;
1680 	default:
1681 		fatalx("invalid process id %d", proc_id);
1682 	}
1683 
1684 	argv[argc++] = (char *)"-f";
1685 	argv[argc++] = (char *)confpath;
1686 
1687 	if (repo_path) {
1688 		argv[argc++] = (char *)"-P";
1689 		argv[argc++] = (char *)repo_path;
1690 	}
1691 
1692 	if (!daemonize)
1693 		argv[argc++] = (char *)"-d";
1694 	if (verbosity > 0)
1695 		argv[argc++] = (char *)"-v";
1696 	if (verbosity > 1)
1697 		argv[argc++] = (char *)"-v";
1698 	argv[argc++] = NULL;
1699 
1700 	execvp(argv0, argv);
1701 	fatal("execvp");
1702 }
1703 
1704 static void
1705 start_listener(char *argv0, const char *confpath, int daemonize, int verbosity)
1706 {
1707 	struct gotd_child_proc *proc;
1708 
1709 	proc = calloc(1, sizeof(*proc));
1710 	if (proc == NULL)
1711 		fatal("calloc");
1712 
1713 	TAILQ_INSERT_HEAD(&procs, proc, entry);
1714 
1715 	/* proc->tmo is initialized in main() after event_init() */
1716 
1717 	proc->type = PROC_LISTEN;
1718 
1719 	if (socketpair(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK,
1720 	    PF_UNSPEC, proc->pipe) == -1)
1721 		fatal("socketpair");
1722 
1723 	proc->pid = start_child(proc->type, NULL, argv0, confpath,
1724 	    proc->pipe[1], daemonize, verbosity);
1725 	imsg_init(&proc->iev.ibuf, proc->pipe[0]);
1726 	proc->iev.handler = gotd_dispatch_listener;
1727 	proc->iev.events = EV_READ;
1728 	proc->iev.handler_arg = NULL;
1729 
1730 	gotd.listen_proc = proc;
1731 }
1732 
1733 static void
1734 start_notifier(char *argv0, const char *confpath, int daemonize, int verbosity)
1735 {
1736 	struct gotd_child_proc *proc;
1737 
1738 	proc = calloc(1, sizeof(*proc));
1739 	if (proc == NULL)
1740 		fatal("calloc");
1741 
1742 	TAILQ_INSERT_HEAD(&procs, proc, entry);
1743 
1744 	/* proc->tmo is initialized in main() after event_init() */
1745 
1746 	proc->type = PROC_NOTIFY;
1747 
1748 	if (socketpair(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK,
1749 	    PF_UNSPEC, proc->pipe) == -1)
1750 		fatal("socketpair");
1751 
1752 	proc->pid = start_child(proc->type, NULL, argv0, confpath,
1753 	    proc->pipe[1], daemonize, verbosity);
1754 	imsg_init(&proc->iev.ibuf, proc->pipe[0]);
1755 	proc->iev.handler = gotd_dispatch_notifier;
1756 	proc->iev.events = EV_READ;
1757 	proc->iev.handler_arg = NULL;
1758 	event_set(&proc->iev.ev, proc->iev.ibuf.fd, EV_READ,
1759 	    gotd_dispatch_notifier, &proc->iev);
1760 
1761 	gotd.notify_proc = proc;
1762 }
1763 
1764 static const struct got_error *
1765 start_session_child(struct gotd_client *client, struct gotd_repo *repo,
1766     char *argv0, const char *confpath, int daemonize, int verbosity)
1767 {
1768 	struct gotd_child_proc *proc;
1769 
1770 	proc = calloc(1, sizeof(*proc));
1771 	if (proc == NULL)
1772 		return got_error_from_errno("calloc");
1773 
1774 	TAILQ_INSERT_HEAD(&procs, proc, entry);
1775 	evtimer_set(&proc->tmo, kill_proc_timeout, proc);
1776 
1777 	if (client_is_reading(client))
1778 		proc->type = PROC_SESSION_READ;
1779 	else
1780 		proc->type = PROC_SESSION_WRITE;
1781 	if (strlcpy(proc->repo_name, repo->name,
1782 	    sizeof(proc->repo_name)) >= sizeof(proc->repo_name))
1783 		fatalx("repository name too long: %s", repo->name);
1784 	log_debug("starting client uid %d session for repository %s",
1785 	    client->euid, repo->name);
1786 	if (strlcpy(proc->repo_path, repo->path, sizeof(proc->repo_path)) >=
1787 	    sizeof(proc->repo_path))
1788 		fatalx("repository path too long: %s", repo->path);
1789 	if (socketpair(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK,
1790 	    PF_UNSPEC, proc->pipe) == -1)
1791 		fatal("socketpair");
1792 	proc->pid = start_child(proc->type, proc->repo_path, argv0,
1793 	    confpath, proc->pipe[1], daemonize, verbosity);
1794 	imsg_init(&proc->iev.ibuf, proc->pipe[0]);
1795 	log_debug("proc %s %s is on fd %d",
1796 	    gotd_proc_names[proc->type], proc->repo_path,
1797 	    proc->pipe[0]);
1798 	proc->iev.handler = gotd_dispatch_client_session;
1799 	proc->iev.events = EV_READ;
1800 	proc->iev.handler_arg = NULL;
1801 	event_set(&proc->iev.ev, proc->iev.ibuf.fd, EV_READ,
1802 	    gotd_dispatch_client_session, &proc->iev);
1803 	gotd_imsg_event_add(&proc->iev);
1804 
1805 	client->session = proc;
1806 	return NULL;
1807 }
1808 
1809 static const struct got_error *
1810 start_repo_child(struct gotd_client *client, enum gotd_procid proc_type,
1811     struct gotd_repo *repo, char *argv0, const char *confpath,
1812     int daemonize, int verbosity)
1813 {
1814 	struct gotd_child_proc *proc;
1815 
1816 	if (proc_type != PROC_REPO_READ && proc_type != PROC_REPO_WRITE)
1817 		return got_error_msg(GOT_ERR_NOT_IMPL, "bad process type");
1818 
1819 	proc = calloc(1, sizeof(*proc));
1820 	if (proc == NULL)
1821 		return got_error_from_errno("calloc");
1822 
1823 	TAILQ_INSERT_HEAD(&procs, proc, entry);
1824 	evtimer_set(&proc->tmo, kill_proc_timeout, proc);
1825 
1826 	proc->type = proc_type;
1827 	if (strlcpy(proc->repo_name, repo->name,
1828 	    sizeof(proc->repo_name)) >= sizeof(proc->repo_name))
1829 		fatalx("repository name too long: %s", repo->name);
1830 	log_debug("starting %s for repository %s",
1831 	    proc->type == PROC_REPO_READ ? "reader" : "writer", repo->name);
1832 	if (strlcpy(proc->repo_path, repo->path, sizeof(proc->repo_path)) >=
1833 	    sizeof(proc->repo_path))
1834 		fatalx("repository path too long: %s", repo->path);
1835 	if (socketpair(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK,
1836 	    PF_UNSPEC, proc->pipe) == -1)
1837 		fatal("socketpair");
1838 	proc->pid = start_child(proc->type, proc->repo_path, argv0,
1839 	    confpath, proc->pipe[1], daemonize, verbosity);
1840 	imsg_init(&proc->iev.ibuf, proc->pipe[0]);
1841 	log_debug("proc %s %s is on fd %d",
1842 	    gotd_proc_names[proc->type], proc->repo_path,
1843 	    proc->pipe[0]);
1844 	proc->iev.handler = gotd_dispatch_repo_child;
1845 	proc->iev.events = EV_READ;
1846 	proc->iev.handler_arg = NULL;
1847 	event_set(&proc->iev.ev, proc->iev.ibuf.fd, EV_READ,
1848 	    gotd_dispatch_repo_child, &proc->iev);
1849 	gotd_imsg_event_add(&proc->iev);
1850 
1851 	client->repo = proc;
1852 	return NULL;
1853 }
1854 
1855 static const struct got_error *
1856 start_auth_child(struct gotd_client *client, int required_auth,
1857     struct gotd_repo *repo, char *argv0, const char *confpath,
1858     int daemonize, int verbosity)
1859 {
1860 	const struct got_error *err = NULL;
1861 	struct gotd_child_proc *proc;
1862 	struct gotd_imsg_auth iauth;
1863 	int fd;
1864 
1865 	memset(&iauth, 0, sizeof(iauth));
1866 
1867 	fd = dup(client->fd);
1868 	if (fd == -1)
1869 		return got_error_from_errno("dup");
1870 
1871 	proc = calloc(1, sizeof(*proc));
1872 	if (proc == NULL) {
1873 		err = got_error_from_errno("calloc");
1874 		close(fd);
1875 		return err;
1876 	}
1877 
1878 	TAILQ_INSERT_HEAD(&procs, proc, entry);
1879 	evtimer_set(&proc->tmo, kill_proc_timeout, proc);
1880 
1881 	proc->type = PROC_AUTH;
1882 	if (strlcpy(proc->repo_name, repo->name,
1883 	    sizeof(proc->repo_name)) >= sizeof(proc->repo_name))
1884 		fatalx("repository name too long: %s", repo->name);
1885 	log_debug("starting auth for uid %d repository %s",
1886 	    client->euid, repo->name);
1887 	if (strlcpy(proc->repo_path, repo->path, sizeof(proc->repo_path)) >=
1888 	    sizeof(proc->repo_path))
1889 		fatalx("repository path too long: %s", repo->path);
1890 	if (socketpair(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK,
1891 	    PF_UNSPEC, proc->pipe) == -1)
1892 		fatal("socketpair");
1893 	proc->pid = start_child(proc->type, proc->repo_path, argv0,
1894 	    confpath, proc->pipe[1], daemonize, verbosity);
1895 	imsg_init(&proc->iev.ibuf, proc->pipe[0]);
1896 	log_debug("proc %s %s is on fd %d",
1897 	    gotd_proc_names[proc->type], proc->repo_path,
1898 	    proc->pipe[0]);
1899 	proc->iev.handler = gotd_dispatch_auth_child;
1900 	proc->iev.events = EV_READ;
1901 	proc->iev.handler_arg = NULL;
1902 	event_set(&proc->iev.ev, proc->iev.ibuf.fd, EV_READ,
1903 	    gotd_dispatch_auth_child, &proc->iev);
1904 	gotd_imsg_event_add(&proc->iev);
1905 
1906 	iauth.euid = client->euid;
1907 	iauth.egid = client->egid;
1908 	iauth.required_auth = required_auth;
1909 	iauth.client_id = client->id;
1910 	if (gotd_imsg_compose_event(&proc->iev, GOTD_IMSG_AUTHENTICATE,
1911 	    PROC_GOTD, fd, &iauth, sizeof(iauth)) == -1) {
1912 		log_warn("imsg compose AUTHENTICATE");
1913 		close(fd);
1914 		/* Let the auth_timeout handler tidy up. */
1915 	}
1916 
1917 	client->auth = proc;
1918 	client->required_auth = required_auth;
1919 	return NULL;
1920 }
1921 
1922 static void
1923 apply_unveil_repo_readonly(const char *repo_path, int need_tmpdir)
1924 {
1925 	if (need_tmpdir) {
1926 		if (unveil(GOT_TMPDIR_STR, "rwc") == -1)
1927 			fatal("unveil %s", GOT_TMPDIR_STR);
1928 	}
1929 
1930 	if (unveil(repo_path, "r") == -1)
1931 		fatal("unveil %s", repo_path);
1932 
1933 	if (unveil(NULL, NULL) == -1)
1934 		fatal("unveil");
1935 }
1936 
1937 static void
1938 apply_unveil_repo_readwrite(const char *repo_path)
1939 {
1940 	if (unveil(repo_path, "rwc") == -1)
1941 		fatal("unveil %s", repo_path);
1942 
1943 	if (unveil(GOT_TMPDIR_STR, "rwc") == -1)
1944 		fatal("unveil %s", GOT_TMPDIR_STR);
1945 
1946 	if (unveil(NULL, NULL) == -1)
1947 		fatal("unveil");
1948 }
1949 
1950 static void
1951 apply_unveil_none(void)
1952 {
1953 	if (unveil("/", "") == -1)
1954 		fatal("unveil");
1955 
1956 	if (unveil(NULL, NULL) == -1)
1957 		fatal("unveil");
1958 }
1959 
1960 static void
1961 apply_unveil_selfexec(void)
1962 {
1963 	if (unveil(gotd.argv0, "x") == -1)
1964 		fatal("unveil %s", gotd.argv0);
1965 
1966 	if (unveil(NULL, NULL) == -1)
1967 		fatal("unveil");
1968 }
1969 
1970 static void
1971 set_max_datasize(void)
1972 {
1973 	struct rlimit rl;
1974 
1975 	if (getrlimit(RLIMIT_DATA, &rl) != 0)
1976 		return;
1977 
1978 	rl.rlim_cur = rl.rlim_max;
1979 	setrlimit(RLIMIT_DATA, &rl);
1980 }
1981 
1982 static void
1983 unveil_notification_helpers(void)
1984 {
1985 	const char *helpers[] = {
1986 	    GOTD_PATH_PROG_NOTIFY_EMAIL,
1987 	    GOTD_PATH_PROG_NOTIFY_HTTP,
1988 	};
1989 	size_t i;
1990 
1991 	for (i = 0; i < nitems(helpers); i++) {
1992 		if (unveil(helpers[i], "x") == 0)
1993 			continue;
1994 		fatal("unveil %s", helpers[i]);
1995 	}
1996 
1997 	if (unveil(NULL, NULL) == -1)
1998 		fatal("unveil");
1999 }
2000 
2001 int
2002 main(int argc, char **argv)
2003 {
2004 	const struct got_error *error = NULL;
2005 	int ch, fd = -1, daemonize = 1, verbosity = 0, noaction = 0;
2006 	const char *confpath = GOTD_CONF_PATH;
2007 	char *argv0 = argv[0];
2008 	char title[2048];
2009 	struct passwd *pw = NULL;
2010 	char *repo_path = NULL;
2011 	enum gotd_procid proc_id = PROC_GOTD;
2012 	struct event evsigint, evsigterm, evsighup, evsigusr1, evsigchld;
2013 	int *pack_fds = NULL, *temp_fds = NULL;
2014 	struct gotd_repo *repo = NULL;
2015 	char *default_sender = NULL;
2016 	char hostname[HOST_NAME_MAX + 1];
2017 	FILE *diff_f1 = NULL, *diff_f2 = NULL;
2018 	int diff_fd1 = -1, diff_fd2 = -1;
2019 
2020 	TAILQ_INIT(&procs);
2021 
2022 	log_init(1, LOG_DAEMON); /* Log to stderr until daemonized. */
2023 
2024 	while ((ch = getopt(argc, argv, "Adf:LnNP:RsSvW")) != -1) {
2025 		switch (ch) {
2026 		case 'A':
2027 			proc_id = PROC_AUTH;
2028 			break;
2029 		case 'd':
2030 			daemonize = 0;
2031 			break;
2032 		case 'f':
2033 			confpath = optarg;
2034 			break;
2035 		case 'L':
2036 			proc_id = PROC_LISTEN;
2037 			break;
2038 		case 'n':
2039 			noaction = 1;
2040 			break;
2041 		case 'N':
2042 			proc_id = PROC_NOTIFY;
2043 			break;
2044 		case 'P':
2045 			repo_path = realpath(optarg, NULL);
2046 			if (repo_path == NULL)
2047 				fatal("realpath '%s'", optarg);
2048 			break;
2049 		case 'R':
2050 			proc_id = PROC_REPO_READ;
2051 			break;
2052 		case 's':
2053 			proc_id = PROC_SESSION_READ;
2054 			break;
2055 		case 'S':
2056 			proc_id = PROC_SESSION_WRITE;
2057 			break;
2058 		case 'v':
2059 			if (verbosity < 3)
2060 				verbosity++;
2061 			break;
2062 		case 'W':
2063 			proc_id = PROC_REPO_WRITE;
2064 			break;
2065 		default:
2066 			usage();
2067 		}
2068 	}
2069 
2070 	argc -= optind;
2071 	argv += optind;
2072 
2073 	if (argc != 0)
2074 		usage();
2075 
2076 	if (geteuid() && (proc_id == PROC_GOTD || proc_id == PROC_LISTEN))
2077 		fatalx("need root privileges");
2078 
2079 	if (parse_config(confpath, proc_id, &gotd) != 0)
2080 		return 1;
2081 
2082 	pw = getpwnam(gotd.user_name);
2083 	if (pw == NULL)
2084 		fatalx("user %s not found", gotd.user_name);
2085 
2086 	if (pw->pw_uid == 0)
2087 		fatalx("cannot run %s as the superuser", getprogname());
2088 
2089 	if (noaction) {
2090 		fprintf(stderr, "configuration OK\n");
2091 		return 0;
2092 	}
2093 
2094 	gotd.argv0 = argv0;
2095 	gotd.daemonize = daemonize;
2096 	gotd.verbosity = verbosity;
2097 	gotd.confpath = confpath;
2098 
2099 	/* Require an absolute path in argv[0] for reliable re-exec. */
2100 	if (!got_path_is_absolute(argv0))
2101 		fatalx("bad path \"%s\": must be an absolute path", argv0);
2102 
2103 	log_init(daemonize ? 0 : 1, LOG_DAEMON);
2104 	log_setverbose(verbosity);
2105 
2106 	if (proc_id == PROC_GOTD) {
2107 		snprintf(title, sizeof(title), "%s", gotd_proc_names[proc_id]);
2108 		arc4random_buf(&clients_hash_key, sizeof(clients_hash_key));
2109 		if (daemonize && daemon(1, 0) == -1)
2110 			fatal("daemon");
2111 		gotd.pid = getpid();
2112 		start_listener(argv0, confpath, daemonize, verbosity);
2113 		start_notifier(argv0, confpath, daemonize, verbosity);
2114 	} else if (proc_id == PROC_LISTEN) {
2115 		snprintf(title, sizeof(title), "%s", gotd_proc_names[proc_id]);
2116 		if (verbosity) {
2117 			log_info("socket: %s", gotd.unix_socket_path);
2118 			log_info("user: %s", pw->pw_name);
2119 		}
2120 
2121 		fd = unix_socket_listen(gotd.unix_socket_path, pw->pw_uid,
2122 		    pw->pw_gid);
2123 		if (fd == -1) {
2124 			fatal("cannot listen on unix socket %s",
2125 			    gotd.unix_socket_path);
2126 		}
2127 	} else if (proc_id == PROC_AUTH) {
2128 		snprintf(title, sizeof(title), "%s %s",
2129 		    gotd_proc_names[proc_id], repo_path);
2130 	} else if (proc_id == PROC_REPO_READ || proc_id == PROC_REPO_WRITE ||
2131 	    proc_id == PROC_SESSION_READ || proc_id == PROC_SESSION_WRITE) {
2132 		error = got_repo_pack_fds_open(&pack_fds);
2133 		if (error != NULL)
2134 			fatalx("cannot open pack tempfiles: %s", error->msg);
2135 		error = got_repo_temp_fds_open(&temp_fds);
2136 		if (error != NULL)
2137 			fatalx("cannot open pack tempfiles: %s", error->msg);
2138 		if (repo_path == NULL)
2139 			fatalx("repository path not specified");
2140 		snprintf(title, sizeof(title), "%s %s",
2141 		    gotd_proc_names[proc_id], repo_path);
2142 	} else if (proc_id == PROC_NOTIFY) {
2143 		snprintf(title, sizeof(title), "%s", gotd_proc_names[proc_id]);
2144 		if (gethostname(hostname, sizeof(hostname)) == -1)
2145 			fatal("gethostname");
2146 		if (asprintf(&default_sender, "%s@%s",
2147 		    pw->pw_name, hostname) == -1)
2148 			fatal("asprintf");
2149 	} else
2150 		fatal("invalid process id %d", proc_id);
2151 
2152 	setproctitle("%s", title);
2153 	log_procinit(title);
2154 
2155 	/* Drop root privileges. */
2156 	if (setgid(pw->pw_gid) == -1)
2157 		fatal("setgid %d failed", pw->pw_gid);
2158 	if (setuid(pw->pw_uid) == -1)
2159 		fatal("setuid %d failed", pw->pw_uid);
2160 
2161 	event_init();
2162 
2163 	switch (proc_id) {
2164 	case PROC_GOTD:
2165 #ifndef PROFILE
2166 		/* "exec" promise will be limited to argv[0] via unveil(2). */
2167 		if (pledge("stdio proc exec sendfd recvfd unveil", NULL) == -1)
2168 			err(1, "pledge");
2169 #endif
2170 		break;
2171 	case PROC_LISTEN:
2172 #ifndef PROFILE
2173 		if (pledge("stdio sendfd unix unveil", NULL) == -1)
2174 			err(1, "pledge");
2175 #endif
2176 		/*
2177 		 * Ensure that AF_UNIX bind(2) cannot be used with any other
2178 		 * sockets by revoking all filesystem access via unveil(2).
2179 		 */
2180 		apply_unveil_none();
2181 
2182 		listen_main(title, fd, gotd.connection_limits,
2183 		    gotd.nconnection_limits);
2184 		/* NOTREACHED */
2185 		break;
2186 	case PROC_AUTH:
2187 #ifndef PROFILE
2188 		if (pledge("stdio getpw recvfd unix unveil", NULL) == -1)
2189 			err(1, "pledge");
2190 #endif
2191 		/*
2192 		 * We need the "unix" pledge promise for getpeername(2) only.
2193 		 * Ensure that AF_UNIX bind(2) cannot be used by revoking all
2194 		 * filesystem access via unveil(2). Access to password database
2195 		 * files will still work since "getpw" bypasses unveil(2).
2196 		 */
2197 		apply_unveil_none();
2198 
2199 		auth_main(title, &gotd.repos, repo_path);
2200 		/* NOTREACHED */
2201 		break;
2202 	case PROC_SESSION_READ:
2203 	case PROC_SESSION_WRITE:
2204 #ifndef PROFILE
2205 		/*
2206 		 * The "recvfd" promise is only needed during setup and
2207 		 * will be removed in a later pledge(2) call.
2208 		 */
2209 		if (pledge("stdio rpath wpath cpath recvfd sendfd fattr flock "
2210 		    "unveil", NULL) == -1)
2211 			err(1, "pledge");
2212 #endif
2213 		if (proc_id == PROC_SESSION_READ)
2214 			apply_unveil_repo_readonly(repo_path, 1);
2215 		else {
2216 			apply_unveil_repo_readwrite(repo_path);
2217 			repo = gotd_find_repo_by_path(repo_path, &gotd);
2218 			if (repo == NULL)
2219 				fatalx("no repository for path %s", repo_path);
2220 		}
2221 		if (proc_id == PROC_SESSION_READ)
2222 			session_read_main(title, repo_path, pack_fds, temp_fds,
2223 			    &gotd.request_timeout, repo);
2224 		else
2225 			session_write_main(title, repo_path, pack_fds, temp_fds,
2226 			    &gotd.request_timeout, repo);
2227 		/* NOTREACHED */
2228 		break;
2229 	case PROC_REPO_READ:
2230 		set_max_datasize();
2231 #ifndef PROFILE
2232 		if (pledge("stdio rpath recvfd unveil", NULL) == -1)
2233 			err(1, "pledge");
2234 #endif
2235 		apply_unveil_repo_readonly(repo_path, 0);
2236 		repo_read_main(title, repo_path, pack_fds, temp_fds);
2237 		/* NOTREACHED */
2238 		exit(0);
2239 	case PROC_REPO_WRITE:
2240 		set_max_datasize();
2241 
2242 		diff_f1 = got_opentemp();
2243 		if (diff_f1 == NULL)
2244 			fatal("got_opentemp");
2245 		diff_f2 = got_opentemp();
2246 		if (diff_f2 == NULL)
2247 			fatal("got_opentemp");
2248 		diff_fd1 = got_opentempfd();
2249 		if (diff_fd1 == -1)
2250 			fatal("got_opentempfd");
2251 		diff_fd2 = got_opentempfd();
2252 		if (diff_fd2 == -1)
2253 			fatal("got_opentempfd");
2254 #ifndef PROFILE
2255 		if (pledge("stdio rpath recvfd unveil", NULL) == -1)
2256 			err(1, "pledge");
2257 #endif
2258 		apply_unveil_repo_readonly(repo_path, 0);
2259 		repo = gotd_find_repo_by_path(repo_path, &gotd);
2260 		if (repo == NULL)
2261 			fatalx("no repository for path %s", repo_path);
2262 		repo_write_main(title, repo_path, pack_fds, temp_fds,
2263 		    diff_f1, diff_f2, diff_fd1, diff_fd2,
2264 		    &repo->protected_tag_namespaces,
2265 		    &repo->protected_branch_namespaces,
2266 		    &repo->protected_branches);
2267 		/* NOTREACHED */
2268 		exit(0);
2269 	case PROC_NOTIFY:
2270 #ifndef PROFILE
2271 		if (pledge("stdio proc exec recvfd unveil", NULL) == -1)
2272 			err(1, "pledge");
2273 #endif
2274 		/*
2275 		 * Limit "exec" promise to notification helpers via unveil(2).
2276 		 */
2277 		unveil_notification_helpers();
2278 
2279 		notify_main(title, &gotd.repos, default_sender);
2280 		/* NOTREACHED */
2281 		exit(0);
2282 	default:
2283 		fatal("invalid process id %d", proc_id);
2284 	}
2285 
2286 	if (proc_id != PROC_GOTD)
2287 		fatal("invalid process id %d", proc_id);
2288 
2289 	evtimer_set(&gotd.listen_proc->tmo, kill_proc_timeout,
2290 	    gotd.listen_proc);
2291 	if (gotd.notify_proc) {
2292 		evtimer_set(&gotd.notify_proc->tmo, kill_proc_timeout,
2293 		    gotd.notify_proc);
2294 	}
2295 
2296 	apply_unveil_selfexec();
2297 
2298 	signal_set(&evsigint, SIGINT, gotd_sighdlr, NULL);
2299 	signal_set(&evsigterm, SIGTERM, gotd_sighdlr, NULL);
2300 	signal_set(&evsighup, SIGHUP, gotd_sighdlr, NULL);
2301 	signal_set(&evsigusr1, SIGUSR1, gotd_sighdlr, NULL);
2302 	signal_set(&evsigchld, SIGCHLD, gotd_sighdlr, NULL);
2303 	signal(SIGPIPE, SIG_IGN);
2304 
2305 	signal_add(&evsigint, NULL);
2306 	signal_add(&evsigterm, NULL);
2307 	signal_add(&evsighup, NULL);
2308 	signal_add(&evsigusr1, NULL);
2309 	signal_add(&evsigchld, NULL);
2310 
2311 	gotd_imsg_event_add(&gotd.listen_proc->iev);
2312 	if (gotd.notify_proc)
2313 		gotd_imsg_event_add(&gotd.notify_proc->iev);
2314 
2315 	event_dispatch();
2316 
2317 	free(repo_path);
2318 	free(default_sender);
2319 	gotd_shutdown();
2320 
2321 	return 0;
2322 }