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Date:: Thu Jun 22 13:10:34 2023 UTC
Message:: update gotd_proc_names after session process unveil changes fixes "proc (null)" appearing in gotd logs
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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/time.h>
19 #include <sys/types.h>
20 #include <sys/stat.h>
21 #include <sys/socket.h>
22 #include <sys/un.h>
23 #include <sys/wait.h>
24 
25 #include <fcntl.h>
26 #include <err.h>
27 #include <errno.h>
28 #include <event.h>
29 #include <limits.h>
30 #include <pwd.h>
31 #include <imsg.h>
32 #include <signal.h>
33 #include <siphash.h>
34 #include <stdarg.h>
35 #include <stdio.h>
36 #include <stdlib.h>
37 #include <string.h>
38 #include <syslog.h>
39 #include <unistd.h>
40 
41 #include "got_error.h"
42 #include "got_opentemp.h"
43 #include "got_path.h"
44 #include "got_repository.h"
45 #include "got_object.h"
46 #include "got_reference.h"
47 
48 #include "got_lib_delta.h"
49 #include "got_lib_object.h"
50 #include "got_lib_object_cache.h"
51 #include "got_lib_hash.h"
52 #include "got_lib_gitproto.h"
53 #include "got_lib_pack.h"
54 #include "got_lib_repository.h"
55 
56 #include "gotd.h"
57 #include "log.h"
58 #include "listen.h"
59 #include "auth.h"
60 #include "session.h"
61 #include "repo_read.h"
62 #include "repo_write.h"
63 
64 #ifndef nitems
65 #define nitems(_a)	(sizeof((_a)) / sizeof((_a)[0]))
66 #endif
67 
68 enum gotd_client_state {
69 	GOTD_CLIENT_STATE_NEW,
70 	GOTD_CLIENT_STATE_ACCESS_GRANTED,
71 };
72 
73 struct gotd_client {
74 	STAILQ_ENTRY(gotd_client)	 entry;
75 	enum gotd_client_state		 state;
76 	uint32_t			 id;
77 	int				 fd;
78 	struct gotd_imsgev		 iev;
79 	struct event			 tmo;
80 	uid_t				 euid;
81 	gid_t				 egid;
82 	struct gotd_child_proc		*repo;
83 	struct gotd_child_proc		*auth;
84 	struct gotd_child_proc		*session;
85 	int				 required_auth;
86 };
87 STAILQ_HEAD(gotd_clients, gotd_client);
88 
89 static struct gotd_clients gotd_clients[GOTD_CLIENT_TABLE_SIZE];
90 static SIPHASH_KEY clients_hash_key;
91 volatile int client_cnt;
92 static struct timeval auth_timeout = { 5, 0 };
93 static struct gotd gotd;
94 
95 void gotd_sighdlr(int sig, short event, void *arg);
96 static void gotd_shutdown(void);
97 static const struct got_error *start_session_child(struct gotd_client *,
98     struct gotd_repo *, char *, const char *, int, int);
99 static const struct got_error *start_repo_child(struct gotd_client *,
100     enum gotd_procid, struct gotd_repo *, char *, const char *, int, int);
101 static const struct got_error *start_auth_child(struct gotd_client *, int,
102     struct gotd_repo *, char *, const char *, int, int);
103 static void kill_proc(struct gotd_child_proc *, int);
104 
105 __dead static void
106 usage(void)
107 {
108 	fprintf(stderr, "usage: %s [-dnv] [-f config-file]\n", getprogname());
109 	exit(1);
110 }
111 
112 static int
113 unix_socket_listen(const char *unix_socket_path, uid_t uid, gid_t gid)
114 {
115 	struct sockaddr_un sun;
116 	int fd = -1;
117 	mode_t old_umask, mode;
118 
119 	fd = socket(AF_UNIX, SOCK_STREAM | SOCK_NONBLOCK| SOCK_CLOEXEC, 0);
120 	if (fd == -1) {
121 		log_warn("socket");
122 		return -1;
123 	}
124 
125 	sun.sun_family = AF_UNIX;
126 	if (strlcpy(sun.sun_path, unix_socket_path,
127 	    sizeof(sun.sun_path)) >= sizeof(sun.sun_path)) {
128 		log_warnx("%s: name too long", unix_socket_path);
129 		close(fd);
130 		return -1;
131 	}
132 
133 	if (unlink(unix_socket_path) == -1) {
134 		if (errno != ENOENT) {
135 			log_warn("unlink %s", unix_socket_path);
136 			close(fd);
137 			return -1;
138 		}
139 	}
140 
141 	old_umask = umask(S_IXUSR|S_IXGRP|S_IWOTH|S_IROTH|S_IXOTH);
142 	mode = S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH;
143 
144 	if (bind(fd, (struct sockaddr *)&sun, sizeof(sun)) == -1) {
145 		log_warn("bind: %s", unix_socket_path);
146 		close(fd);
147 		umask(old_umask);
148 		return -1;
149 	}
150 
151 	umask(old_umask);
152 
153 	if (chmod(unix_socket_path, mode) == -1) {
154 		log_warn("chmod %o %s", mode, unix_socket_path);
155 		close(fd);
156 		unlink(unix_socket_path);
157 		return -1;
158 	}
159 
160 	if (chown(unix_socket_path, uid, gid) == -1) {
161 		log_warn("chown %s uid=%d gid=%d", unix_socket_path, uid, gid);
162 		close(fd);
163 		unlink(unix_socket_path);
164 		return -1;
165 	}
166 
167 	if (listen(fd, GOTD_UNIX_SOCKET_BACKLOG) == -1) {
168 		log_warn("listen");
169 		close(fd);
170 		unlink(unix_socket_path);
171 		return -1;
172 	}
173 
174 	return fd;
175 }
176 
177 static uint64_t
178 client_hash(uint32_t client_id)
179 {
180 	return SipHash24(&clients_hash_key, &client_id, sizeof(client_id));
181 }
182 
183 static void
184 add_client(struct gotd_client *client)
185 {
186 	uint64_t slot = client_hash(client->id) % nitems(gotd_clients);
187 	STAILQ_INSERT_HEAD(&gotd_clients[slot], client, entry);
188 	client_cnt++;
189 }
190 
191 static struct gotd_client *
192 find_client(uint32_t client_id)
193 {
194 	uint64_t slot;
195 	struct gotd_client *c;
196 
197 	slot = client_hash(client_id) % nitems(gotd_clients);
198 	STAILQ_FOREACH(c, &gotd_clients[slot], entry) {
199 		if (c->id == client_id)
200 			return c;
201 	}
202 
203 	return NULL;
204 }
205 
206 static struct gotd_client *
207 find_client_by_proc_fd(int fd)
208 {
209 	uint64_t slot;
210 
211 	for (slot = 0; slot < nitems(gotd_clients); slot++) {
212 		struct gotd_client *c;
213 
214 		STAILQ_FOREACH(c, &gotd_clients[slot], entry) {
215 			if (c->repo && c->repo->iev.ibuf.fd == fd)
216 				return c;
217 			if (c->auth && c->auth->iev.ibuf.fd == fd)
218 				return c;
219 			if (c->session && c->session->iev.ibuf.fd == fd)
220 				return c;
221 		}
222 	}
223 
224 	return NULL;
225 }
226 
227 static int
228 client_is_reading(struct gotd_client *client)
229 {
230 	return (client->required_auth &
231 	    (GOTD_AUTH_READ | GOTD_AUTH_WRITE)) == GOTD_AUTH_READ;
232 }
233 
234 static int
235 client_is_writing(struct gotd_client *client)
236 {
237 	return (client->required_auth &
238 	    (GOTD_AUTH_READ | GOTD_AUTH_WRITE)) ==
239 	    (GOTD_AUTH_READ | GOTD_AUTH_WRITE);
240 }
241 
242 static const struct got_error *
243 ensure_client_is_not_writing(struct gotd_client *client)
244 {
245 	if (client_is_writing(client)) {
246 		return got_error_fmt(GOT_ERR_BAD_PACKET,
247 		    "uid %d made a read-request but is writing to "
248 		    "a repository", client->euid);
249 	}
250 
251 	return NULL;
252 }
253 
254 static const struct got_error *
255 ensure_client_is_not_reading(struct gotd_client *client)
256 {
257 	if (client_is_reading(client)) {
258 		return got_error_fmt(GOT_ERR_BAD_PACKET,
259 		    "uid %d made a write-request but is reading from "
260 		    "a repository", client->euid);
261 	}
262 
263 	return NULL;
264 }
265 
266 static void
267 wait_for_child(pid_t child_pid)
268 {
269 	pid_t pid;
270 	int status;
271 
272 	log_debug("waiting for child PID %ld to terminate",
273 	    (long)child_pid);
274 
275 	do {
276 		pid = waitpid(child_pid, &status, WNOHANG);
277 		if (pid == -1) {
278 			if (errno != EINTR && errno != ECHILD)
279 				fatal("wait");
280 		} else if (WIFSIGNALED(status)) {
281 			log_warnx("child PID %ld terminated; signal %d",
282 			    (long)pid, WTERMSIG(status));
283 		}
284 	} while (pid != -1 || (pid == -1 && errno == EINTR));
285 }
286 
287 static void
288 proc_done(struct gotd_child_proc *proc)
289 {
290 	event_del(&proc->iev.ev);
291 	msgbuf_clear(&proc->iev.ibuf.w);
292 	close(proc->iev.ibuf.fd);
293 	kill_proc(proc, 0);
294 	wait_for_child(proc->pid);
295 	free(proc);
296 }
297 
298 static void
299 kill_auth_proc(struct gotd_client *client)
300 {
301 	struct gotd_child_proc *proc;
302 
303 	if (client->auth == NULL)
304 		return;
305 
306 	proc = client->auth;
307 	client->auth = NULL;
308 
309 	proc_done(proc);
310 }
311 
312 static void
313 kill_session_proc(struct gotd_client *client)
314 {
315 	struct gotd_child_proc *proc;
316 
317 	if (client->session == NULL)
318 		return;
319 
320 	proc = client->session;
321 	client->session = NULL;
322 
323 	proc_done(proc);
324 }
325 
326 static void
327 disconnect(struct gotd_client *client)
328 {
329 	struct gotd_imsg_disconnect idisconnect;
330 	struct gotd_child_proc *proc = client->repo;
331 	struct gotd_child_proc *listen_proc = &gotd.listen_proc;
332 	uint64_t slot;
333 
334 	log_debug("uid %d: disconnecting", client->euid);
335 
336 	kill_auth_proc(client);
337 	kill_session_proc(client);
338 
339 	if (proc) {
340 		event_del(&proc->iev.ev);
341 		msgbuf_clear(&proc->iev.ibuf.w);
342 		close(proc->iev.ibuf.fd);
343 		kill_proc(proc, 0);
344 		wait_for_child(proc->pid);
345 		free(proc);
346 		proc = NULL;
347 	}
348 
349 	idisconnect.client_id = client->id;
350 	if (gotd_imsg_compose_event(&listen_proc->iev,
351 	    GOTD_IMSG_DISCONNECT, PROC_GOTD, -1,
352 	    &idisconnect, sizeof(idisconnect)) == -1)
353 		log_warn("imsg compose DISCONNECT");
354 
355 	slot = client_hash(client->id) % nitems(gotd_clients);
356 	STAILQ_REMOVE(&gotd_clients[slot], client, gotd_client, entry);
357 	imsg_clear(&client->iev.ibuf);
358 	event_del(&client->iev.ev);
359 	evtimer_del(&client->tmo);
360 	if (client->fd != -1)
361 		close(client->fd);
362 	else if (client->iev.ibuf.fd != -1)
363 		close(client->iev.ibuf.fd);
364 	free(client);
365 	client_cnt--;
366 }
367 
368 static void
369 disconnect_on_error(struct gotd_client *client, const struct got_error *err)
370 {
371 	struct imsgbuf ibuf;
372 
373 	log_warnx("uid %d: %s", client->euid, err->msg);
374 	if (err->code != GOT_ERR_EOF && client->fd != -1) {
375 		imsg_init(&ibuf, client->fd);
376 		gotd_imsg_send_error(&ibuf, 0, PROC_GOTD, err);
377 		imsg_clear(&ibuf);
378 	}
379 	disconnect(client);
380 }
381 
382 static const struct got_error *
383 send_repo_info(struct gotd_imsgev *iev, struct gotd_repo *repo)
384 {
385 	const struct got_error *err = NULL;
386 	struct gotd_imsg_info_repo irepo;
387 
388 	memset(&irepo, 0, sizeof(irepo));
389 
390 	if (strlcpy(irepo.repo_name, repo->name, sizeof(irepo.repo_name))
391 	    >= sizeof(irepo.repo_name))
392 		return got_error_msg(GOT_ERR_NO_SPACE, "repo name too long");
393 	if (strlcpy(irepo.repo_path, repo->path, sizeof(irepo.repo_path))
394 	    >= sizeof(irepo.repo_path))
395 		return got_error_msg(GOT_ERR_NO_SPACE, "repo path too long");
396 
397 	if (gotd_imsg_compose_event(iev, GOTD_IMSG_INFO_REPO, PROC_GOTD, -1,
398 	    &irepo, sizeof(irepo)) == -1) {
399 		err = got_error_from_errno("imsg compose INFO_REPO");
400 		if (err)
401 			return err;
402 	}
403 
404 	return NULL;
405 }
406 
407 static const struct got_error *
408 send_client_info(struct gotd_imsgev *iev, struct gotd_client *client)
409 {
410 	const struct got_error *err = NULL;
411 	struct gotd_imsg_info_client iclient;
412 	struct gotd_child_proc *proc;
413 
414 	memset(&iclient, 0, sizeof(iclient));
415 	iclient.euid = client->euid;
416 	iclient.egid = client->egid;
417 
418 	proc = client->repo;
419 	if (proc) {
420 		if (strlcpy(iclient.repo_name, proc->repo_path,
421 		    sizeof(iclient.repo_name)) >= sizeof(iclient.repo_name)) {
422 			return got_error_msg(GOT_ERR_NO_SPACE,
423 			    "repo name too long");
424 		}
425 		if (client_is_writing(client))
426 			iclient.is_writing = 1;
427 
428 		iclient.repo_child_pid = proc->pid;
429 	}
430 
431 	if (client->session)
432 		iclient.session_child_pid = client->session->pid;
433 
434 	if (gotd_imsg_compose_event(iev, GOTD_IMSG_INFO_CLIENT, PROC_GOTD, -1,
435 	    &iclient, sizeof(iclient)) == -1) {
436 		err = got_error_from_errno("imsg compose INFO_CLIENT");
437 		if (err)
438 			return err;
439 	}
440 
441 	return NULL;
442 }
443 
444 static const struct got_error *
445 send_info(struct gotd_client *client)
446 {
447 	const struct got_error *err = NULL;
448 	struct gotd_imsg_info info;
449 	uint64_t slot;
450 	struct gotd_repo *repo;
451 
452 	if (client->euid != 0)
453 		return got_error_set_errno(EPERM, "info");
454 
455 	info.pid = gotd.pid;
456 	info.verbosity = gotd.verbosity;
457 	info.nrepos = gotd.nrepos;
458 	info.nclients = client_cnt - 1;
459 
460 	if (gotd_imsg_compose_event(&client->iev, GOTD_IMSG_INFO, PROC_GOTD, -1,
461 	    &info, sizeof(info)) == -1) {
462 		err = got_error_from_errno("imsg compose INFO");
463 		if (err)
464 			return err;
465 	}
466 
467 	TAILQ_FOREACH(repo, &gotd.repos, entry) {
468 		err = send_repo_info(&client->iev, repo);
469 		if (err)
470 			return err;
471 	}
472 
473 	for (slot = 0; slot < nitems(gotd_clients); slot++) {
474 		struct gotd_client *c;
475 		STAILQ_FOREACH(c, &gotd_clients[slot], entry) {
476 			if (c->id == client->id)
477 				continue;
478 			err = send_client_info(&client->iev, c);
479 			if (err)
480 				return err;
481 		}
482 	}
483 
484 	return NULL;
485 }
486 
487 static const struct got_error *
488 stop_gotd(struct gotd_client *client)
489 {
490 
491 	if (client->euid != 0)
492 		return got_error_set_errno(EPERM, "stop");
493 
494 	gotd_shutdown();
495 	/* NOTREACHED */
496 	return NULL;
497 }
498 
499 static const struct got_error *
500 start_client_authentication(struct gotd_client *client, struct imsg *imsg)
501 {
502 	const struct got_error *err;
503 	struct gotd_imsg_list_refs ireq;
504 	struct gotd_repo *repo = NULL;
505 	size_t datalen;
506 
507 	log_debug("list-refs request from uid %d", client->euid);
508 
509 	if (client->state != GOTD_CLIENT_STATE_NEW)
510 		return got_error_msg(GOT_ERR_BAD_REQUEST,
511 		    "unexpected list-refs request received");
512 
513 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
514 	if (datalen != sizeof(ireq))
515 		return got_error(GOT_ERR_PRIVSEP_LEN);
516 
517 	memcpy(&ireq, imsg->data, datalen);
518 
519 	if (ireq.client_is_reading) {
520 		err = ensure_client_is_not_writing(client);
521 		if (err)
522 			return err;
523 		repo = gotd_find_repo_by_name(ireq.repo_name, &gotd);
524 		if (repo == NULL)
525 			return got_error(GOT_ERR_NOT_GIT_REPO);
526 		err = start_auth_child(client, GOTD_AUTH_READ, repo,
527 		    gotd.argv0, gotd.confpath, gotd.daemonize,
528 		    gotd.verbosity);
529 		if (err)
530 			return err;
531 	} else {
532 		err = ensure_client_is_not_reading(client);
533 		if (err)
534 			return err;
535 		repo = gotd_find_repo_by_name(ireq.repo_name, &gotd);
536 		if (repo == NULL)
537 			return got_error(GOT_ERR_NOT_GIT_REPO);
538 		err = start_auth_child(client,
539 		    GOTD_AUTH_READ | GOTD_AUTH_WRITE,
540 		    repo, gotd.argv0, gotd.confpath, gotd.daemonize,
541 		    gotd.verbosity);
542 		if (err)
543 			return err;
544 	}
545 
546 	evtimer_add(&client->tmo, &auth_timeout);
547 
548 	/* Flow continues upon authentication successs/failure or timeout. */
549 	return NULL;
550 }
551 
552 static void
553 gotd_request(int fd, short events, void *arg)
554 {
555 	struct gotd_imsgev *iev = arg;
556 	struct imsgbuf *ibuf = &iev->ibuf;
557 	struct gotd_client *client = iev->handler_arg;
558 	const struct got_error *err = NULL;
559 	struct imsg imsg;
560 	ssize_t n;
561 
562 	if (events & EV_WRITE) {
563 		while (ibuf->w.queued) {
564 			n = msgbuf_write(&ibuf->w);
565 			if (n == -1 && errno == EPIPE) {
566 				/*
567 				 * The client has closed its socket.
568 				 * This can happen when Git clients are
569 				 * done sending pack file data.
570 				 */
571 				msgbuf_clear(&ibuf->w);
572 				continue;
573 			} else if (n == -1 && errno != EAGAIN) {
574 				err = got_error_from_errno("imsg_flush");
575 				disconnect_on_error(client, err);
576 				return;
577 			}
578 			if (n == 0) {
579 				/* Connection closed. */
580 				err = got_error(GOT_ERR_EOF);
581 				disconnect_on_error(client, err);
582 				return;
583 			}
584 		}
585 
586 		/* Disconnect gotctl(8) now that messages have been sent. */
587 		if (!client_is_reading(client) && !client_is_writing(client)) {
588 			disconnect(client);
589 			return;
590 		}
591 	}
592 
593 	if ((events & EV_READ) == 0)
594 		return;
595 
596 	memset(&imsg, 0, sizeof(imsg));
597 
598 	while (err == NULL) {
599 		err = gotd_imsg_recv(&imsg, ibuf, 0);
600 		if (err) {
601 			if (err->code == GOT_ERR_PRIVSEP_READ)
602 				err = NULL;
603 			break;
604 		}
605 
606 		evtimer_del(&client->tmo);
607 
608 		switch (imsg.hdr.type) {
609 		case GOTD_IMSG_INFO:
610 			err = send_info(client);
611 			break;
612 		case GOTD_IMSG_STOP:
613 			err = stop_gotd(client);
614 			break;
615 		case GOTD_IMSG_LIST_REFS:
616 			err = start_client_authentication(client, &imsg);
617 			break;
618 		default:
619 			log_debug("unexpected imsg %d", imsg.hdr.type);
620 			err = got_error(GOT_ERR_PRIVSEP_MSG);
621 			break;
622 		}
623 
624 		imsg_free(&imsg);
625 	}
626 
627 	if (err) {
628 		disconnect_on_error(client, err);
629 	} else {
630 		gotd_imsg_event_add(&client->iev);
631 	}
632 }
633 
634 static void
635 gotd_auth_timeout(int fd, short events, void *arg)
636 {
637 	struct gotd_client *client = arg;
638 
639 	log_debug("disconnecting uid %d due to authentication timeout",
640 	    client->euid);
641 	disconnect(client);
642 }
643 
644 static const struct got_error *
645 recv_connect(uint32_t *client_id, struct imsg *imsg)
646 {
647 	const struct got_error *err = NULL;
648 	struct gotd_imsg_connect iconnect;
649 	size_t datalen;
650 	int s = -1;
651 	struct gotd_client *client = NULL;
652 
653 	*client_id = 0;
654 
655 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
656 	if (datalen != sizeof(iconnect))
657 		return got_error(GOT_ERR_PRIVSEP_LEN);
658 	memcpy(&iconnect, imsg->data, sizeof(iconnect));
659 
660 	s = imsg->fd;
661 	if (s == -1) {
662 		err = got_error(GOT_ERR_PRIVSEP_NO_FD);
663 		goto done;
664 	}
665 
666 	if (find_client(iconnect.client_id)) {
667 		err = got_error_msg(GOT_ERR_CLIENT_ID, "duplicate client ID");
668 		goto done;
669 	}
670 
671 	client = calloc(1, sizeof(*client));
672 	if (client == NULL) {
673 		err = got_error_from_errno("calloc");
674 		goto done;
675 	}
676 
677 	*client_id = iconnect.client_id;
678 
679 	client->state = GOTD_CLIENT_STATE_NEW;
680 	client->id = iconnect.client_id;
681 	client->fd = s;
682 	s = -1;
683 	/* The auth process will verify UID/GID for us. */
684 	client->euid = iconnect.euid;
685 	client->egid = iconnect.egid;
686 
687 	imsg_init(&client->iev.ibuf, client->fd);
688 	client->iev.handler = gotd_request;
689 	client->iev.events = EV_READ;
690 	client->iev.handler_arg = client;
691 
692 	event_set(&client->iev.ev, client->fd, EV_READ, gotd_request,
693 	    &client->iev);
694 	gotd_imsg_event_add(&client->iev);
695 
696 	evtimer_set(&client->tmo, gotd_auth_timeout, client);
697 
698 	add_client(client);
699 	log_debug("%s: new client uid %d connected on fd %d", __func__,
700 	    client->euid, client->fd);
701 done:
702 	if (err) {
703 		struct gotd_child_proc *listen_proc = &gotd.listen_proc;
704 		struct gotd_imsg_disconnect idisconnect;
705 
706 		idisconnect.client_id = client->id;
707 		if (gotd_imsg_compose_event(&listen_proc->iev,
708 		    GOTD_IMSG_DISCONNECT, PROC_GOTD, -1,
709 		    &idisconnect, sizeof(idisconnect)) == -1)
710 			log_warn("imsg compose DISCONNECT");
711 
712 		if (s != -1)
713 			close(s);
714 	}
715 
716 	return err;
717 }
718 
719 static const char *gotd_proc_names[PROC_MAX] = {
720 	"parent",
721 	"listen",
722 	"auth",
723 	"session_read",
724 	"session_write",
725 	"repo_read",
726 	"repo_write"
727 };
728 
729 static void
730 kill_proc(struct gotd_child_proc *proc, int fatal)
731 {
732 	if (fatal) {
733 		log_warnx("sending SIGKILL to PID %d", proc->pid);
734 		kill(proc->pid, SIGKILL);
735 	} else
736 		kill(proc->pid, SIGTERM);
737 }
738 
739 static void
740 gotd_shutdown(void)
741 {
742 	struct gotd_child_proc *proc;
743 	uint64_t slot;
744 
745 	log_debug("shutting down");
746 	for (slot = 0; slot < nitems(gotd_clients); slot++) {
747 		struct gotd_client *c, *tmp;
748 
749 		STAILQ_FOREACH_SAFE(c, &gotd_clients[slot], entry, tmp)
750 			disconnect(c);
751 	}
752 
753 	proc = &gotd.listen_proc;
754 	msgbuf_clear(&proc->iev.ibuf.w);
755 	close(proc->iev.ibuf.fd);
756 	kill_proc(proc, 0);
757 	wait_for_child(proc->pid);
758 
759 	log_info("terminating");
760 	exit(0);
761 }
762 
763 void
764 gotd_sighdlr(int sig, short event, void *arg)
765 {
766 	/*
767 	 * Normal signal handler rules don't apply because libevent
768 	 * decouples for us.
769 	 */
770 
771 	switch (sig) {
772 	case SIGHUP:
773 		log_info("%s: ignoring SIGHUP", __func__);
774 		break;
775 	case SIGUSR1:
776 		log_info("%s: ignoring SIGUSR1", __func__);
777 		break;
778 	case SIGTERM:
779 	case SIGINT:
780 		gotd_shutdown();
781 		break;
782 	default:
783 		fatalx("unexpected signal");
784 	}
785 }
786 
787 static const struct got_error *
788 ensure_proc_is_reading(struct gotd_client *client,
789     struct gotd_child_proc *proc)
790 {
791 	if (!client_is_reading(client)) {
792 		kill_proc(proc, 1);
793 		return got_error_fmt(GOT_ERR_BAD_PACKET,
794 		    "PID %d handled a read-request for uid %d but this "
795 		    "user is not reading from a repository", proc->pid,
796 		    client->euid);
797 	}
798 
799 	return NULL;
800 }
801 
802 static const struct got_error *
803 ensure_proc_is_writing(struct gotd_client *client,
804     struct gotd_child_proc *proc)
805 {
806 	if (!client_is_writing(client)) {
807 		kill_proc(proc, 1);
808 		return got_error_fmt(GOT_ERR_BAD_PACKET,
809 		    "PID %d handled a write-request for uid %d but this "
810 		    "user is not writing to a repository", proc->pid,
811 		    client->euid);
812 	}
813 
814 	return NULL;
815 }
816 
817 static int
818 verify_imsg_src(struct gotd_client *client, struct gotd_child_proc *proc,
819     struct imsg *imsg)
820 {
821 	const struct got_error *err;
822 	int ret = 0;
823 
824 	if (proc->type == PROC_REPO_READ || proc->type == PROC_REPO_WRITE) {
825 		if (client->repo == NULL)
826 			fatalx("no process found for uid %d", client->euid);
827 		if (proc->pid != client->repo->pid) {
828 			kill_proc(proc, 1);
829 			log_warnx("received message from PID %d for uid %d, "
830 			    "while PID %d is the process serving this user",
831 			    proc->pid, client->euid, client->repo->pid);
832 			return 0;
833 		}
834 	}
835 	if (proc->type == PROC_SESSION_READ ||
836 	    proc->type == PROC_SESSION_WRITE) {
837 		if (client->session == NULL) {
838 			log_warnx("no session found for uid %d", client->euid);
839 			return 0;
840 		}
841 		if (proc->pid != client->session->pid) {
842 			kill_proc(proc, 1);
843 			log_warnx("received message from PID %d for uid %d, "
844 			    "while PID %d is the process serving this user",
845 			    proc->pid, client->euid, client->session->pid);
846 			return 0;
847 		}
848 	}
849 
850 	switch (imsg->hdr.type) {
851 	case GOTD_IMSG_ERROR:
852 		ret = 1;
853 		break;
854 	case GOTD_IMSG_CONNECT:
855 		if (proc->type != PROC_LISTEN) {
856 			err = got_error_fmt(GOT_ERR_BAD_PACKET,
857 			    "new connection for uid %d from PID %d "
858 			    "which is not the listen process",
859 			    proc->pid, client->euid);
860 		} else
861 			ret = 1;
862 		break;
863 	case GOTD_IMSG_ACCESS_GRANTED:
864 		if (proc->type != PROC_AUTH) {
865 			err = got_error_fmt(GOT_ERR_BAD_PACKET,
866 			    "authentication of uid %d from PID %d "
867 			    "which is not the auth process",
868 			    proc->pid, client->euid);
869 		} else
870 			ret = 1;
871 		break;
872 	case GOTD_IMSG_CLIENT_SESSION_READY:
873 		if (proc->type != PROC_SESSION_READ &&
874 		    proc->type != PROC_SESSION_WRITE) {
875 			err = got_error_fmt(GOT_ERR_BAD_PACKET,
876 			    "unexpected \"ready\" signal from PID %d",
877 			    proc->pid);
878 		} else
879 			ret = 1;
880 		break;
881 	case GOTD_IMSG_REPO_CHILD_READY:
882 		if (proc->type != PROC_REPO_READ &&
883 		    proc->type != PROC_REPO_WRITE) {
884 			err = got_error_fmt(GOT_ERR_BAD_PACKET,
885 			    "unexpected \"ready\" signal from PID %d",
886 			    proc->pid);
887 		} else
888 			ret = 1;
889 		break;
890 	case GOTD_IMSG_PACKFILE_DONE:
891 		err = ensure_proc_is_reading(client, proc);
892 		if (err)
893 			log_warnx("uid %d: %s", client->euid, err->msg);
894 		else
895 			ret = 1;
896 		break;
897 	case GOTD_IMSG_PACKFILE_INSTALL:
898 	case GOTD_IMSG_REF_UPDATES_START:
899 	case GOTD_IMSG_REF_UPDATE:
900 		err = ensure_proc_is_writing(client, proc);
901 		if (err)
902 			log_warnx("uid %d: %s", client->euid, err->msg);
903 		else
904 			ret = 1;
905 		break;
906 	default:
907 		log_debug("%s: unexpected imsg %d", __func__, imsg->hdr.type);
908 		break;
909 	}
910 
911 	return ret;
912 }
913 
914 static const struct got_error *
915 connect_repo_child(struct gotd_client *client,
916     struct gotd_child_proc *repo_proc)
917 {
918 	static const struct got_error *err;
919 	struct gotd_imsgev *session_iev = &client->session->iev;
920 	struct gotd_imsg_connect_repo_child ireq;
921 	int pipe[2];
922 
923 	if (client->state != GOTD_CLIENT_STATE_ACCESS_GRANTED)
924 		return got_error_msg(GOT_ERR_BAD_REQUEST,
925 		    "unexpected repo child ready signal received");
926 
927 	if (socketpair(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK,
928 	    PF_UNSPEC, pipe) == -1)
929 		fatal("socketpair");
930 
931 	memset(&ireq, 0, sizeof(ireq));
932 	ireq.client_id = client->id;
933 	ireq.proc_id = repo_proc->type;
934 
935 	/* Pass repo child pipe to session child process. */
936 	if (gotd_imsg_compose_event(session_iev, GOTD_IMSG_CONNECT_REPO_CHILD,
937 	    PROC_GOTD, pipe[0], &ireq, sizeof(ireq)) == -1) {
938 		err = got_error_from_errno("imsg compose CONNECT_REPO_CHILD");
939 		close(pipe[0]);
940 		close(pipe[1]);
941 		return err;
942 	}
943 
944 	/* Pass session child pipe to repo child process. */
945 	if (gotd_imsg_compose_event(&repo_proc->iev,
946 	    GOTD_IMSG_CONNECT_REPO_CHILD, PROC_GOTD, pipe[1], NULL, 0) == -1) {
947 		err = got_error_from_errno("imsg compose CONNECT_REPO_CHILD");
948 		close(pipe[1]);
949 		return err;
950 	}
951 
952 	return NULL;
953 }
954 
955 static void
956 gotd_dispatch_listener(int fd, short event, void *arg)
957 {
958 	struct gotd_imsgev *iev = arg;
959 	struct imsgbuf *ibuf = &iev->ibuf;
960 	struct gotd_child_proc *proc = &gotd.listen_proc;
961 	ssize_t n;
962 	int shut = 0;
963 	struct imsg imsg;
964 
965 	if (proc->iev.ibuf.fd != fd)
966 		fatalx("%s: unexpected fd %d", __func__, fd);
967 
968 	if (event & EV_READ) {
969 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
970 			fatal("imsg_read error");
971 		if (n == 0) {
972 			/* Connection closed. */
973 			shut = 1;
974 			goto done;
975 		}
976 	}
977 
978 	if (event & EV_WRITE) {
979 		n = msgbuf_write(&ibuf->w);
980 		if (n == -1 && errno != EAGAIN)
981 			fatal("msgbuf_write");
982 		if (n == 0) {
983 			/* Connection closed. */
984 			shut = 1;
985 			goto done;
986 		}
987 	}
988 
989 	for (;;) {
990 		const struct got_error *err = NULL;
991 		struct gotd_client *client = NULL;
992 		uint32_t client_id = 0;
993 		int do_disconnect = 0;
994 
995 		if ((n = imsg_get(ibuf, &imsg)) == -1)
996 			fatal("%s: imsg_get error", __func__);
997 		if (n == 0)	/* No more messages. */
998 			break;
999 
1000 		switch (imsg.hdr.type) {
1001 		case GOTD_IMSG_ERROR:
1002 			do_disconnect = 1;
1003 			err = gotd_imsg_recv_error(&client_id, &imsg);
1004 			break;
1005 		case GOTD_IMSG_CONNECT:
1006 			err = recv_connect(&client_id, &imsg);
1007 			break;
1008 		default:
1009 			log_debug("unexpected imsg %d", imsg.hdr.type);
1010 			break;
1011 		}
1012 
1013 		client = find_client(client_id);
1014 		if (client == NULL) {
1015 			log_warnx("%s: client not found", __func__);
1016 			imsg_free(&imsg);
1017 			continue;
1018 		}
1019 
1020 		if (err)
1021 			log_warnx("uid %d: %s", client->euid, err->msg);
1022 
1023 		if (do_disconnect) {
1024 			if (err)
1025 				disconnect_on_error(client, err);
1026 			else
1027 				disconnect(client);
1028 		}
1029 
1030 		imsg_free(&imsg);
1031 	}
1032 done:
1033 	if (!shut) {
1034 		gotd_imsg_event_add(iev);
1035 	} else {
1036 		/* This pipe is dead. Remove its event handler */
1037 		event_del(&iev->ev);
1038 		event_loopexit(NULL);
1039 	}
1040 }
1041 
1042 static void
1043 gotd_dispatch_auth_child(int fd, short event, void *arg)
1044 {
1045 	const struct got_error *err = NULL;
1046 	struct gotd_imsgev *iev = arg;
1047 	struct imsgbuf *ibuf = &iev->ibuf;
1048 	struct gotd_client *client;
1049 	struct gotd_repo *repo = NULL;
1050 	ssize_t n;
1051 	int shut = 0;
1052 	struct imsg imsg;
1053 	uint32_t client_id = 0;
1054 	int do_disconnect = 0;
1055 
1056 	client = find_client_by_proc_fd(fd);
1057 	if (client == NULL) {
1058 		/* Can happen during process teardown. */
1059 		warnx("cannot find client for fd %d", fd);
1060 		shut = 1;
1061 		goto done;
1062 	}
1063 
1064 	if (client->auth == NULL)
1065 		fatalx("cannot find auth child process for fd %d", 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 		}
1085 		goto done;
1086 	}
1087 
1088 	if (client->auth->iev.ibuf.fd != fd)
1089 		fatalx("%s: unexpected fd %d", __func__, fd);
1090 
1091 	if ((n = imsg_get(ibuf, &imsg)) == -1)
1092 		fatal("%s: imsg_get error", __func__);
1093 	if (n == 0)	/* No more messages. */
1094 		return;
1095 
1096 	evtimer_del(&client->tmo);
1097 
1098 	switch (imsg.hdr.type) {
1099 	case GOTD_IMSG_ERROR:
1100 		do_disconnect = 1;
1101 		err = gotd_imsg_recv_error(&client_id, &imsg);
1102 		break;
1103 	case GOTD_IMSG_ACCESS_GRANTED:
1104 		client->state = GOTD_CLIENT_STATE_ACCESS_GRANTED;
1105 		break;
1106 	default:
1107 		do_disconnect = 1;
1108 		log_debug("unexpected imsg %d", imsg.hdr.type);
1109 		break;
1110 	}
1111 
1112 	if (!verify_imsg_src(client, client->auth, &imsg)) {
1113 		do_disconnect = 1;
1114 		log_debug("dropping imsg type %d from PID %d",
1115 		    imsg.hdr.type, client->auth->pid);
1116 	}
1117 	imsg_free(&imsg);
1118 
1119 	if (do_disconnect) {
1120 		if (err)
1121 			disconnect_on_error(client, err);
1122 		else
1123 			disconnect(client);
1124 		return;
1125 	}
1126 
1127 	repo = gotd_find_repo_by_name(client->auth->repo_name, &gotd);
1128 	if (repo == NULL) {
1129 		err = got_error(GOT_ERR_NOT_GIT_REPO);
1130 		goto done;
1131 	}
1132 	kill_auth_proc(client);
1133 
1134 	log_info("authenticated uid %d for repository %s",
1135 	    client->euid, repo->name);
1136 
1137 	err = start_session_child(client, repo, gotd.argv0,
1138 	    gotd.confpath, gotd.daemonize, gotd.verbosity);
1139 	if (err)
1140 		goto done;
1141 done:
1142 	if (err)
1143 		log_warnx("uid %d: %s", client->euid, err->msg);
1144 
1145 	/* We might have killed the auth process by now. */
1146 	if (client->auth != NULL) {
1147 		if (!shut) {
1148 			gotd_imsg_event_add(iev);
1149 		} else {
1150 			/* This pipe is dead. Remove its event handler */
1151 			event_del(&iev->ev);
1152 		}
1153 	}
1154 }
1155 
1156 static const struct got_error *
1157 connect_session(struct gotd_client *client)
1158 {
1159 	const struct got_error *err = NULL;
1160 	struct gotd_imsg_connect iconnect;
1161 	int s;
1162 
1163 	memset(&iconnect, 0, sizeof(iconnect));
1164 
1165 	s = dup(client->fd);
1166 	if (s == -1)
1167 		return got_error_from_errno("dup");
1168 
1169 	iconnect.client_id = client->id;
1170 	iconnect.euid = client->euid;
1171 	iconnect.egid = client->egid;
1172 
1173 	if (gotd_imsg_compose_event(&client->session->iev, GOTD_IMSG_CONNECT,
1174 	    PROC_GOTD, s, &iconnect, sizeof(iconnect)) == -1) {
1175 		err = got_error_from_errno("imsg compose CONNECT");
1176 		close(s);
1177 		return err;
1178 	}
1179 
1180 	/*
1181 	 * We are no longer interested in messages from this client.
1182 	 * Further client requests will be handled by the session process.
1183 	 */
1184 	msgbuf_clear(&client->iev.ibuf.w);
1185 	imsg_clear(&client->iev.ibuf);
1186 	event_del(&client->iev.ev);
1187 	client->fd = -1; /* will be closed via copy in client->iev.ibuf.fd */
1188 
1189 	return NULL;
1190 }
1191 
1192 static void
1193 gotd_dispatch_client_session(int fd, short event, void *arg)
1194 {
1195 	struct gotd_imsgev *iev = arg;
1196 	struct imsgbuf *ibuf = &iev->ibuf;
1197 	struct gotd_child_proc *proc = NULL;
1198 	struct gotd_client *client = NULL;
1199 	ssize_t n;
1200 	int shut = 0;
1201 	struct imsg imsg;
1202 
1203 	client = find_client_by_proc_fd(fd);
1204 	if (client == NULL) {
1205 		/* Can happen during process teardown. */
1206 		warnx("cannot find client for fd %d", fd);
1207 		shut = 1;
1208 		goto done;
1209 	}
1210 
1211 	if (event & EV_READ) {
1212 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
1213 			fatal("imsg_read error");
1214 		if (n == 0) {
1215 			/* Connection closed. */
1216 			shut = 1;
1217 			goto done;
1218 		}
1219 	}
1220 
1221 	if (event & EV_WRITE) {
1222 		n = msgbuf_write(&ibuf->w);
1223 		if (n == -1 && errno != EAGAIN)
1224 			fatal("msgbuf_write");
1225 		if (n == 0) {
1226 			/* Connection closed. */
1227 			shut = 1;
1228 			goto done;
1229 		}
1230 	}
1231 
1232 	proc = client->session;
1233 	if (proc == NULL)
1234 		fatalx("cannot find session child process for fd %d", fd);
1235 
1236 	for (;;) {
1237 		const struct got_error *err = NULL;
1238 		uint32_t client_id = 0;
1239 		int do_disconnect = 0, do_start_repo_child = 0;
1240 
1241 		if ((n = imsg_get(ibuf, &imsg)) == -1)
1242 			fatal("%s: imsg_get error", __func__);
1243 		if (n == 0)	/* No more messages. */
1244 			break;
1245 
1246 		switch (imsg.hdr.type) {
1247 		case GOTD_IMSG_ERROR:
1248 			do_disconnect = 1;
1249 			err = gotd_imsg_recv_error(&client_id, &imsg);
1250 			break;
1251 		case GOTD_IMSG_CLIENT_SESSION_READY:
1252 			if (client->state != GOTD_CLIENT_STATE_ACCESS_GRANTED) {
1253 				err = got_error(GOT_ERR_PRIVSEP_MSG);
1254 				break;
1255 			}
1256 			do_start_repo_child = 1;
1257 			break;
1258 		case GOTD_IMSG_DISCONNECT:
1259 			do_disconnect = 1;
1260 			break;
1261 		default:
1262 			log_debug("unexpected imsg %d", imsg.hdr.type);
1263 			break;
1264 		}
1265 
1266 		if (!verify_imsg_src(client, proc, &imsg)) {
1267 			log_debug("dropping imsg type %d from PID %d",
1268 			    imsg.hdr.type, proc->pid);
1269 			imsg_free(&imsg);
1270 			continue;
1271 		}
1272 		if (err)
1273 			log_warnx("uid %d: %s", client->euid, err->msg);
1274 
1275 		if (do_start_repo_child) {
1276 			struct gotd_repo *repo;
1277 			const char *name = client->session->repo_name;
1278 
1279 			repo = gotd_find_repo_by_name(name, &gotd);
1280 			if (repo != NULL) {
1281 				enum gotd_procid proc_type;
1282 
1283 				if (client->required_auth & GOTD_AUTH_WRITE)
1284 					proc_type = PROC_REPO_WRITE;
1285 				else
1286 					proc_type = PROC_REPO_READ;
1287 
1288 				err = start_repo_child(client, proc_type, repo,
1289 				    gotd.argv0, gotd.confpath, gotd.daemonize,
1290 				    gotd.verbosity);
1291 			} else
1292 				err = got_error(GOT_ERR_NOT_GIT_REPO);
1293 
1294 			if (err) {
1295 				log_warnx("uid %d: %s", client->euid, err->msg);
1296 				do_disconnect = 1;
1297 			}
1298 		}
1299 
1300 		if (do_disconnect) {
1301 			if (err)
1302 				disconnect_on_error(client, err);
1303 			else
1304 				disconnect(client);
1305 		}
1306 
1307 		imsg_free(&imsg);
1308 	}
1309 done:
1310 	if (!shut) {
1311 		gotd_imsg_event_add(iev);
1312 	} else {
1313 		/* This pipe is dead. Remove its event handler */
1314 		event_del(&iev->ev);
1315 		disconnect(client);
1316 	}
1317 }
1318 
1319 static void
1320 gotd_dispatch_repo_child(int fd, short event, void *arg)
1321 {
1322 	struct gotd_imsgev *iev = arg;
1323 	struct imsgbuf *ibuf = &iev->ibuf;
1324 	struct gotd_child_proc *proc = NULL;
1325 	struct gotd_client *client;
1326 	ssize_t n;
1327 	int shut = 0;
1328 	struct imsg imsg;
1329 
1330 	client = find_client_by_proc_fd(fd);
1331 	if (client == NULL) {
1332 		/* Can happen during process teardown. */
1333 		warnx("cannot find client for fd %d", fd);
1334 		shut = 1;
1335 		goto done;
1336 	}
1337 
1338 	if (event & EV_READ) {
1339 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
1340 			fatal("imsg_read error");
1341 		if (n == 0) {
1342 			/* Connection closed. */
1343 			shut = 1;
1344 			goto done;
1345 		}
1346 	}
1347 
1348 	if (event & EV_WRITE) {
1349 		n = msgbuf_write(&ibuf->w);
1350 		if (n == -1 && errno != EAGAIN)
1351 			fatal("msgbuf_write");
1352 		if (n == 0) {
1353 			/* Connection closed. */
1354 			shut = 1;
1355 			goto done;
1356 		}
1357 	}
1358 
1359 	proc = client->repo;
1360 	if (proc == NULL)
1361 		fatalx("cannot find child process for fd %d", fd);
1362 
1363 	for (;;) {
1364 		const struct got_error *err = NULL;
1365 		uint32_t client_id = 0;
1366 		int do_disconnect = 0;
1367 
1368 		if ((n = imsg_get(ibuf, &imsg)) == -1)
1369 			fatal("%s: imsg_get error", __func__);
1370 		if (n == 0)	/* No more messages. */
1371 			break;
1372 
1373 		switch (imsg.hdr.type) {
1374 		case GOTD_IMSG_ERROR:
1375 			do_disconnect = 1;
1376 			err = gotd_imsg_recv_error(&client_id, &imsg);
1377 			break;
1378 		case GOTD_IMSG_REPO_CHILD_READY:
1379 			err = connect_session(client);
1380 			if (err)
1381 				break;
1382 			err = connect_repo_child(client, proc);
1383 			break;
1384 		default:
1385 			log_debug("unexpected imsg %d", imsg.hdr.type);
1386 			break;
1387 		}
1388 
1389 		if (!verify_imsg_src(client, proc, &imsg)) {
1390 			log_debug("dropping imsg type %d from PID %d",
1391 			    imsg.hdr.type, proc->pid);
1392 			imsg_free(&imsg);
1393 			continue;
1394 		}
1395 		if (err)
1396 			log_warnx("uid %d: %s", client->euid, err->msg);
1397 
1398 		if (do_disconnect) {
1399 			if (err)
1400 				disconnect_on_error(client, err);
1401 			else
1402 				disconnect(client);
1403 		}
1404 
1405 		imsg_free(&imsg);
1406 	}
1407 done:
1408 	if (!shut) {
1409 		gotd_imsg_event_add(iev);
1410 	} else {
1411 		/* This pipe is dead. Remove its event handler */
1412 		event_del(&iev->ev);
1413 		disconnect(client);
1414 	}
1415 }
1416 
1417 static pid_t
1418 start_child(enum gotd_procid proc_id, const char *repo_path,
1419     char *argv0, const char *confpath, int fd, int daemonize, int verbosity)
1420 {
1421 	char	*argv[11];
1422 	int	 argc = 0;
1423 	pid_t	 pid;
1424 
1425 	switch (pid = fork()) {
1426 	case -1:
1427 		fatal("cannot fork");
1428 	case 0:
1429 		break;
1430 	default:
1431 		close(fd);
1432 		return pid;
1433 	}
1434 
1435 	if (fd != GOTD_FILENO_MSG_PIPE) {
1436 		if (dup2(fd, GOTD_FILENO_MSG_PIPE) == -1)
1437 			fatal("cannot setup imsg fd");
1438 	} else if (fcntl(fd, F_SETFD, 0) == -1)
1439 		fatal("cannot setup imsg fd");
1440 
1441 	argv[argc++] = argv0;
1442 	switch (proc_id) {
1443 	case PROC_LISTEN:
1444 		argv[argc++] = (char *)"-L";
1445 		break;
1446 	case PROC_AUTH:
1447 		argv[argc++] = (char *)"-A";
1448 		break;
1449 	case PROC_SESSION_READ:
1450 		argv[argc++] = (char *)"-s";
1451 		break;
1452 	case PROC_SESSION_WRITE:
1453 		argv[argc++] = (char *)"-S";
1454 		break;
1455 	case PROC_REPO_READ:
1456 		argv[argc++] = (char *)"-R";
1457 		break;
1458 	case PROC_REPO_WRITE:
1459 		argv[argc++] = (char *)"-W";
1460 		break;
1461 	default:
1462 		fatalx("invalid process id %d", proc_id);
1463 	}
1464 
1465 	argv[argc++] = (char *)"-f";
1466 	argv[argc++] = (char *)confpath;
1467 
1468 	if (repo_path) {
1469 		argv[argc++] = (char *)"-P";
1470 		argv[argc++] = (char *)repo_path;
1471 	}
1472 
1473 	if (!daemonize)
1474 		argv[argc++] = (char *)"-d";
1475 	if (verbosity > 0)
1476 		argv[argc++] = (char *)"-v";
1477 	if (verbosity > 1)
1478 		argv[argc++] = (char *)"-v";
1479 	argv[argc++] = NULL;
1480 
1481 	execvp(argv0, argv);
1482 	fatal("execvp");
1483 }
1484 
1485 static void
1486 start_listener(char *argv0, const char *confpath, int daemonize, int verbosity)
1487 {
1488 	struct gotd_child_proc *proc = &gotd.listen_proc;
1489 
1490 	proc->type = PROC_LISTEN;
1491 
1492 	if (socketpair(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK,
1493 	    PF_UNSPEC, proc->pipe) == -1)
1494 		fatal("socketpair");
1495 
1496 	proc->pid = start_child(proc->type, NULL, argv0, confpath,
1497 	    proc->pipe[1], daemonize, verbosity);
1498 	imsg_init(&proc->iev.ibuf, proc->pipe[0]);
1499 	proc->iev.handler = gotd_dispatch_listener;
1500 	proc->iev.events = EV_READ;
1501 	proc->iev.handler_arg = NULL;
1502 }
1503 
1504 static const struct got_error *
1505 start_session_child(struct gotd_client *client, struct gotd_repo *repo,
1506     char *argv0, const char *confpath, int daemonize, int verbosity)
1507 {
1508 	struct gotd_child_proc *proc;
1509 
1510 	proc = calloc(1, sizeof(*proc));
1511 	if (proc == NULL)
1512 		return got_error_from_errno("calloc");
1513 
1514 	if (client_is_reading(client))
1515 		proc->type = PROC_SESSION_READ;
1516 	else
1517 		proc->type = PROC_SESSION_WRITE;
1518 	if (strlcpy(proc->repo_name, repo->name,
1519 	    sizeof(proc->repo_name)) >= sizeof(proc->repo_name))
1520 		fatalx("repository name too long: %s", repo->name);
1521 	log_debug("starting client uid %d session for repository %s",
1522 	    client->euid, repo->name);
1523 	if (strlcpy(proc->repo_path, repo->path, sizeof(proc->repo_path)) >=
1524 	    sizeof(proc->repo_path))
1525 		fatalx("repository path too long: %s", repo->path);
1526 	if (socketpair(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK,
1527 	    PF_UNSPEC, proc->pipe) == -1)
1528 		fatal("socketpair");
1529 	proc->pid = start_child(proc->type, proc->repo_path, argv0,
1530 	    confpath, proc->pipe[1], daemonize, verbosity);
1531 	imsg_init(&proc->iev.ibuf, proc->pipe[0]);
1532 	log_debug("proc %s %s is on fd %d",
1533 	    gotd_proc_names[proc->type], proc->repo_path,
1534 	    proc->pipe[0]);
1535 	proc->iev.handler = gotd_dispatch_client_session;
1536 	proc->iev.events = EV_READ;
1537 	proc->iev.handler_arg = NULL;
1538 	event_set(&proc->iev.ev, proc->iev.ibuf.fd, EV_READ,
1539 	    gotd_dispatch_client_session, &proc->iev);
1540 	gotd_imsg_event_add(&proc->iev);
1541 
1542 	client->session = proc;
1543 	return NULL;
1544 }
1545 
1546 static const struct got_error *
1547 start_repo_child(struct gotd_client *client, enum gotd_procid proc_type,
1548     struct gotd_repo *repo, char *argv0, const char *confpath,
1549     int daemonize, int verbosity)
1550 {
1551 	struct gotd_child_proc *proc;
1552 
1553 	if (proc_type != PROC_REPO_READ && proc_type != PROC_REPO_WRITE)
1554 		return got_error_msg(GOT_ERR_NOT_IMPL, "bad process type");
1555 
1556 	proc = calloc(1, sizeof(*proc));
1557 	if (proc == NULL)
1558 		return got_error_from_errno("calloc");
1559 
1560 	proc->type = proc_type;
1561 	if (strlcpy(proc->repo_name, repo->name,
1562 	    sizeof(proc->repo_name)) >= sizeof(proc->repo_name))
1563 		fatalx("repository name too long: %s", repo->name);
1564 	log_debug("starting %s for repository %s",
1565 	    proc->type == PROC_REPO_READ ? "reader" : "writer", repo->name);
1566 	if (strlcpy(proc->repo_path, repo->path, sizeof(proc->repo_path)) >=
1567 	    sizeof(proc->repo_path))
1568 		fatalx("repository path too long: %s", repo->path);
1569 	if (socketpair(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK,
1570 	    PF_UNSPEC, proc->pipe) == -1)
1571 		fatal("socketpair");
1572 	proc->pid = start_child(proc->type, proc->repo_path, argv0,
1573 	    confpath, proc->pipe[1], daemonize, verbosity);
1574 	imsg_init(&proc->iev.ibuf, proc->pipe[0]);
1575 	log_debug("proc %s %s is on fd %d",
1576 	    gotd_proc_names[proc->type], proc->repo_path,
1577 	    proc->pipe[0]);
1578 	proc->iev.handler = gotd_dispatch_repo_child;
1579 	proc->iev.events = EV_READ;
1580 	proc->iev.handler_arg = NULL;
1581 	event_set(&proc->iev.ev, proc->iev.ibuf.fd, EV_READ,
1582 	    gotd_dispatch_repo_child, &proc->iev);
1583 	gotd_imsg_event_add(&proc->iev);
1584 
1585 	client->repo = proc;
1586 	return NULL;
1587 }
1588 
1589 static const struct got_error *
1590 start_auth_child(struct gotd_client *client, int required_auth,
1591     struct gotd_repo *repo, char *argv0, const char *confpath,
1592     int daemonize, int verbosity)
1593 {
1594 	const struct got_error *err = NULL;
1595 	struct gotd_child_proc *proc;
1596 	struct gotd_imsg_auth iauth;
1597 	int fd;
1598 
1599 	memset(&iauth, 0, sizeof(iauth));
1600 
1601 	fd = dup(client->fd);
1602 	if (fd == -1)
1603 		return got_error_from_errno("dup");
1604 
1605 	proc = calloc(1, sizeof(*proc));
1606 	if (proc == NULL) {
1607 		err = got_error_from_errno("calloc");
1608 		close(fd);
1609 		return err;
1610 	}
1611 
1612 	proc->type = PROC_AUTH;
1613 	if (strlcpy(proc->repo_name, repo->name,
1614 	    sizeof(proc->repo_name)) >= sizeof(proc->repo_name))
1615 		fatalx("repository name too long: %s", repo->name);
1616 	log_debug("starting auth for uid %d repository %s",
1617 	    client->euid, repo->name);
1618 	if (strlcpy(proc->repo_path, repo->path, sizeof(proc->repo_path)) >=
1619 	    sizeof(proc->repo_path))
1620 		fatalx("repository path too long: %s", repo->path);
1621 	if (socketpair(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK,
1622 	    PF_UNSPEC, proc->pipe) == -1)
1623 		fatal("socketpair");
1624 	proc->pid = start_child(proc->type, proc->repo_path, argv0,
1625 	    confpath, proc->pipe[1], daemonize, verbosity);
1626 	imsg_init(&proc->iev.ibuf, proc->pipe[0]);
1627 	log_debug("proc %s %s is on fd %d",
1628 	    gotd_proc_names[proc->type], proc->repo_path,
1629 	    proc->pipe[0]);
1630 	proc->iev.handler = gotd_dispatch_auth_child;
1631 	proc->iev.events = EV_READ;
1632 	proc->iev.handler_arg = NULL;
1633 	event_set(&proc->iev.ev, proc->iev.ibuf.fd, EV_READ,
1634 	    gotd_dispatch_auth_child, &proc->iev);
1635 	gotd_imsg_event_add(&proc->iev);
1636 
1637 	iauth.euid = client->euid;
1638 	iauth.egid = client->egid;
1639 	iauth.required_auth = required_auth;
1640 	iauth.client_id = client->id;
1641 	if (gotd_imsg_compose_event(&proc->iev, GOTD_IMSG_AUTHENTICATE,
1642 	    PROC_GOTD, fd, &iauth, sizeof(iauth)) == -1) {
1643 		log_warn("imsg compose AUTHENTICATE");
1644 		close(fd);
1645 		/* Let the auth_timeout handler tidy up. */
1646 	}
1647 
1648 	client->auth = proc;
1649 	client->required_auth = required_auth;
1650 	return NULL;
1651 }
1652 
1653 static void
1654 apply_unveil_repo_readonly(const char *repo_path, int need_tmpdir)
1655 {
1656 	if (need_tmpdir) {
1657 		if (unveil(GOT_TMPDIR_STR, "rwc") == -1)
1658 			fatal("unveil %s", GOT_TMPDIR_STR);
1659 	}
1660 
1661 	if (unveil(repo_path, "r") == -1)
1662 		fatal("unveil %s", repo_path);
1663 
1664 	if (unveil(NULL, NULL) == -1)
1665 		fatal("unveil");
1666 }
1667 
1668 static void
1669 apply_unveil_repo_readwrite(const char *repo_path)
1670 {
1671 	if (unveil(repo_path, "rwc") == -1)
1672 		fatal("unveil %s", repo_path);
1673 
1674 	if (unveil(GOT_TMPDIR_STR, "rwc") == -1)
1675 		fatal("unveil %s", GOT_TMPDIR_STR);
1676 
1677 	if (unveil(NULL, NULL) == -1)
1678 		fatal("unveil");
1679 }
1680 
1681 static void
1682 apply_unveil_none(void)
1683 {
1684 	if (unveil("/", "") == -1)
1685 		fatal("unveil");
1686 
1687 	if (unveil(NULL, NULL) == -1)
1688 		fatal("unveil");
1689 }
1690 
1691 static void
1692 apply_unveil_selfexec(void)
1693 {
1694 	if (unveil(gotd.argv0, "x") == -1)
1695 		fatal("unveil %s", gotd.argv0);
1696 
1697 	if (unveil(NULL, NULL) == -1)
1698 		fatal("unveil");
1699 }
1700 
1701 int
1702 main(int argc, char **argv)
1703 {
1704 	const struct got_error *error = NULL;
1705 	int ch, fd = -1, daemonize = 1, verbosity = 0, noaction = 0;
1706 	const char *confpath = GOTD_CONF_PATH;
1707 	char *argv0 = argv[0];
1708 	char title[2048];
1709 	struct passwd *pw = NULL;
1710 	char *repo_path = NULL;
1711 	enum gotd_procid proc_id = PROC_GOTD;
1712 	struct event evsigint, evsigterm, evsighup, evsigusr1;
1713 	int *pack_fds = NULL, *temp_fds = NULL;
1714 	struct gotd_repo *repo = NULL;
1715 
1716 	log_init(1, LOG_DAEMON); /* Log to stderr until daemonized. */
1717 
1718 	while ((ch = getopt(argc, argv, "Adf:LnP:RsSvW")) != -1) {
1719 		switch (ch) {
1720 		case 'A':
1721 			proc_id = PROC_AUTH;
1722 			break;
1723 		case 'd':
1724 			daemonize = 0;
1725 			break;
1726 		case 'f':
1727 			confpath = optarg;
1728 			break;
1729 		case 'L':
1730 			proc_id = PROC_LISTEN;
1731 			break;
1732 		case 'n':
1733 			noaction = 1;
1734 			break;
1735 		case 'P':
1736 			repo_path = realpath(optarg, NULL);
1737 			if (repo_path == NULL)
1738 				fatal("realpath '%s'", optarg);
1739 			break;
1740 		case 'R':
1741 			proc_id = PROC_REPO_READ;
1742 			break;
1743 		case 's':
1744 			proc_id = PROC_SESSION_READ;
1745 			break;
1746 		case 'S':
1747 			proc_id = PROC_SESSION_WRITE;
1748 			break;
1749 		case 'v':
1750 			if (verbosity < 3)
1751 				verbosity++;
1752 			break;
1753 		case 'W':
1754 			proc_id = PROC_REPO_WRITE;
1755 			break;
1756 		default:
1757 			usage();
1758 		}
1759 	}
1760 
1761 	argc -= optind;
1762 	argv += optind;
1763 
1764 	if (argc != 0)
1765 		usage();
1766 
1767 	if (geteuid() && (proc_id == PROC_GOTD || proc_id == PROC_LISTEN))
1768 		fatalx("need root privileges");
1769 
1770 	if (parse_config(confpath, proc_id, &gotd, 1) != 0)
1771 		return 1;
1772 
1773 	pw = getpwnam(gotd.user_name);
1774 	if (pw == NULL)
1775 		fatalx("user %s not found", gotd.user_name);
1776 
1777 	if (pw->pw_uid == 0)
1778 		fatalx("cannot run %s as the superuser", getprogname());
1779 
1780 	if (noaction) {
1781 		fprintf(stderr, "configuration OK\n");
1782 		return 0;
1783 	}
1784 
1785 	gotd.argv0 = argv0;
1786 	gotd.daemonize = daemonize;
1787 	gotd.verbosity = verbosity;
1788 	gotd.confpath = confpath;
1789 
1790 	/* Require an absolute path in argv[0] for reliable re-exec. */
1791 	if (!got_path_is_absolute(argv0))
1792 		fatalx("bad path \"%s\": must be an absolute path", argv0);
1793 
1794 	log_init(daemonize ? 0 : 1, LOG_DAEMON);
1795 	log_setverbose(verbosity);
1796 
1797 	if (proc_id == PROC_GOTD) {
1798 		snprintf(title, sizeof(title), "%s", gotd_proc_names[proc_id]);
1799 		arc4random_buf(&clients_hash_key, sizeof(clients_hash_key));
1800 		if (daemonize && daemon(1, 0) == -1)
1801 			fatal("daemon");
1802 		gotd.pid = getpid();
1803 		start_listener(argv0, confpath, daemonize, verbosity);
1804 	} else if (proc_id == PROC_LISTEN) {
1805 		snprintf(title, sizeof(title), "%s", gotd_proc_names[proc_id]);
1806 		if (verbosity) {
1807 			log_info("socket: %s", gotd.unix_socket_path);
1808 			log_info("user: %s", pw->pw_name);
1809 		}
1810 
1811 		fd = unix_socket_listen(gotd.unix_socket_path, pw->pw_uid,
1812 		    pw->pw_gid);
1813 		if (fd == -1) {
1814 			fatal("cannot listen on unix socket %s",
1815 			    gotd.unix_socket_path);
1816 		}
1817 	} else if (proc_id == PROC_AUTH) {
1818 		snprintf(title, sizeof(title), "%s %s",
1819 		    gotd_proc_names[proc_id], repo_path);
1820 	} else if (proc_id == PROC_REPO_READ || proc_id == PROC_REPO_WRITE ||
1821 	    proc_id == PROC_SESSION_READ || proc_id == PROC_SESSION_WRITE) {
1822 		error = got_repo_pack_fds_open(&pack_fds);
1823 		if (error != NULL)
1824 			fatalx("cannot open pack tempfiles: %s", error->msg);
1825 		error = got_repo_temp_fds_open(&temp_fds);
1826 		if (error != NULL)
1827 			fatalx("cannot open pack tempfiles: %s", error->msg);
1828 		if (repo_path == NULL)
1829 			fatalx("repository path not specified");
1830 		snprintf(title, sizeof(title), "%s %s",
1831 		    gotd_proc_names[proc_id], repo_path);
1832 	} else
1833 		fatal("invalid process id %d", proc_id);
1834 
1835 	setproctitle("%s", title);
1836 	log_procinit(title);
1837 
1838 	/* Drop root privileges. */
1839 	if (setgid(pw->pw_gid) == -1)
1840 		fatal("setgid %d failed", pw->pw_gid);
1841 	if (setuid(pw->pw_uid) == -1)
1842 		fatal("setuid %d failed", pw->pw_uid);
1843 
1844 	event_init();
1845 
1846 	switch (proc_id) {
1847 	case PROC_GOTD:
1848 #ifndef PROFILE
1849 		/* "exec" promise will be limited to argv[0] via unveil(2). */
1850 		if (pledge("stdio proc exec sendfd recvfd unveil", NULL) == -1)
1851 			err(1, "pledge");
1852 #endif
1853 		break;
1854 	case PROC_LISTEN:
1855 #ifndef PROFILE
1856 		if (pledge("stdio sendfd unix unveil", NULL) == -1)
1857 			err(1, "pledge");
1858 #endif
1859 		/*
1860 		 * Ensure that AF_UNIX bind(2) cannot be used with any other
1861 		 * sockets by revoking all filesystem access via unveil(2).
1862 		 */
1863 		apply_unveil_none();
1864 
1865 		listen_main(title, fd, gotd.connection_limits,
1866 		    gotd.nconnection_limits);
1867 		/* NOTREACHED */
1868 		break;
1869 	case PROC_AUTH:
1870 #ifndef PROFILE
1871 		if (pledge("stdio getpw recvfd unix unveil", NULL) == -1)
1872 			err(1, "pledge");
1873 #endif
1874 		/*
1875 		 * We need the "unix" pledge promise for getpeername(2) only.
1876 		 * Ensure that AF_UNIX bind(2) cannot be used by revoking all
1877 		 * filesystem access via unveil(2). Access to password database
1878 		 * files will still work since "getpw" bypasses unveil(2).
1879 		 */
1880 		apply_unveil_none();
1881 
1882 		auth_main(title, &gotd.repos, repo_path);
1883 		/* NOTREACHED */
1884 		break;
1885 	case PROC_SESSION_READ:
1886 	case PROC_SESSION_WRITE:
1887 #ifndef PROFILE
1888 		/*
1889 		 * The "recvfd" promise is only needed during setup and
1890 		 * will be removed in a later pledge(2) call.
1891 		 */
1892 		if (pledge("stdio rpath wpath cpath recvfd sendfd fattr flock "
1893 		    "unveil", NULL) == -1)
1894 			err(1, "pledge");
1895 #endif
1896 		if (proc_id == PROC_SESSION_READ)
1897 			apply_unveil_repo_readonly(repo_path, 1);
1898 		else
1899 			apply_unveil_repo_readwrite(repo_path);
1900 		session_main(title, repo_path, pack_fds, temp_fds,
1901 		    &gotd.request_timeout, proc_id);
1902 		/* NOTREACHED */
1903 		break;
1904 	case PROC_REPO_READ:
1905 #ifndef PROFILE
1906 		if (pledge("stdio rpath recvfd unveil", NULL) == -1)
1907 			err(1, "pledge");
1908 #endif
1909 		apply_unveil_repo_readonly(repo_path, 0);
1910 		repo_read_main(title, repo_path, pack_fds, temp_fds);
1911 		/* NOTREACHED */
1912 		exit(0);
1913 	case PROC_REPO_WRITE:
1914 #ifndef PROFILE
1915 		if (pledge("stdio rpath recvfd unveil", NULL) == -1)
1916 			err(1, "pledge");
1917 #endif
1918 		apply_unveil_repo_readonly(repo_path, 0);
1919 		repo = gotd_find_repo_by_path(repo_path, &gotd);
1920 		if (repo == NULL)
1921 			fatalx("no repository for path %s", repo_path);
1922 		repo_write_main(title, repo_path, pack_fds, temp_fds,
1923 		    &repo->protected_tag_namespaces,
1924 		    &repo->protected_branch_namespaces,
1925 		    &repo->protected_branches);
1926 		/* NOTREACHED */
1927 		exit(0);
1928 	default:
1929 		fatal("invalid process id %d", proc_id);
1930 	}
1931 
1932 	if (proc_id != PROC_GOTD)
1933 		fatal("invalid process id %d", proc_id);
1934 
1935 	apply_unveil_selfexec();
1936 
1937 	signal_set(&evsigint, SIGINT, gotd_sighdlr, NULL);
1938 	signal_set(&evsigterm, SIGTERM, gotd_sighdlr, NULL);
1939 	signal_set(&evsighup, SIGHUP, gotd_sighdlr, NULL);
1940 	signal_set(&evsigusr1, SIGUSR1, gotd_sighdlr, NULL);
1941 	signal(SIGPIPE, SIG_IGN);
1942 
1943 	signal_add(&evsigint, NULL);
1944 	signal_add(&evsigterm, NULL);
1945 	signal_add(&evsighup, NULL);
1946 	signal_add(&evsigusr1, NULL);
1947 
1948 	gotd_imsg_event_add(&gotd.listen_proc.iev);
1949 
1950 	event_dispatch();
1951 
1952 	free(repo_path);
1953 	gotd_shutdown();
1954 
1955 	return 0;
1956 }