xref: /openbsd-src/usr.bin/tmux/client.c (revision 9b9d2a55a62c8e82206c25f94fcc7f4e2765250e)
1 /* $OpenBSD: client.c,v 1.93 2015/08/30 22:40:25 nicm Exp $ */
2 
3 /*
4  * Copyright (c) 2007 Nicholas Marriott <nicm@users.sourceforge.net>
5  *
6  * Permission to use, copy, modify, and distribute this software for any
7  * purpose with or without fee is hereby granted, provided that the above
8  * copyright notice and this permission notice appear in all copies.
9  *
10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14  * WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER
15  * IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
16  * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17  */
18 
19 #include <sys/types.h>
20 #include <sys/file.h>
21 #include <sys/socket.h>
22 #include <sys/stat.h>
23 #include <sys/un.h>
24 #include <sys/wait.h>
25 
26 #include <errno.h>
27 #include <event.h>
28 #include <fcntl.h>
29 #include <signal.h>
30 #include <stdlib.h>
31 #include <string.h>
32 #include <unistd.h>
33 
34 #include "tmux.h"
35 
36 int		client_flags;
37 struct imsgbuf	client_ibuf;
38 struct event	client_event;
39 struct event	client_stdin;
40 enum {
41 	CLIENT_EXIT_NONE,
42 	CLIENT_EXIT_DETACHED,
43 	CLIENT_EXIT_DETACHED_HUP,
44 	CLIENT_EXIT_LOST_TTY,
45 	CLIENT_EXIT_TERMINATED,
46 	CLIENT_EXIT_LOST_SERVER,
47 	CLIENT_EXIT_EXITED,
48 	CLIENT_EXIT_SERVER_EXITED,
49 } client_exitreason = CLIENT_EXIT_NONE;
50 int		client_exitval;
51 enum msgtype	client_exittype;
52 const char     *client_exitsession;
53 int		client_attached;
54 
55 __dead void	client_exec(const char *);
56 int		client_get_lock(char *);
57 int		client_connect(struct event_base *, char *, int);
58 void		client_send_identify(void);
59 int		client_write_one(enum msgtype, int, const void *, size_t);
60 int		client_write_server(enum msgtype, const void *, size_t);
61 void		client_update_event(void);
62 void		client_signal(int, short, void *);
63 void		client_stdin_callback(int, short, void *);
64 void		client_write(int, const char *, size_t);
65 void		client_callback(int, short, void *);
66 int		client_dispatch_attached(void);
67 int		client_dispatch_wait(void);
68 const char     *client_exit_message(void);
69 
70 /*
71  * Get server create lock. If already held then server start is happening in
72  * another client, so block until the lock is released and return -1 to
73  * retry. Ignore other errors - just continue and start the server without the
74  * lock.
75  */
76 int
77 client_get_lock(char *lockfile)
78 {
79 	int lockfd;
80 
81 	if ((lockfd = open(lockfile, O_WRONLY|O_CREAT, 0600)) == -1)
82 		fatal("open failed");
83 	log_debug("lock file is %s", lockfile);
84 
85 	if (flock(lockfd, LOCK_EX|LOCK_NB) == -1) {
86 		log_debug("flock failed: %s", strerror(errno));
87 		if (errno != EAGAIN)
88 			return (lockfd);
89 		while (flock(lockfd, LOCK_EX) == -1 && errno == EINTR)
90 			/* nothing */;
91 		close(lockfd);
92 		return (-1);
93 	}
94 	log_debug("flock succeeded");
95 
96 	return (lockfd);
97 }
98 
99 /* Connect client to server. */
100 int
101 client_connect(struct event_base *base, char *path, int start_server)
102 {
103 	struct sockaddr_un	sa;
104 	size_t			size;
105 	int			fd, lockfd = -1, locked = 0;
106 	char		       *lockfile = NULL;
107 
108 	memset(&sa, 0, sizeof sa);
109 	sa.sun_family = AF_UNIX;
110 	size = strlcpy(sa.sun_path, path, sizeof sa.sun_path);
111 	if (size >= sizeof sa.sun_path) {
112 		errno = ENAMETOOLONG;
113 		return (-1);
114 	}
115 	log_debug("socket is %s", path);
116 
117 retry:
118 	if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1)
119 		fatal("socket failed");
120 
121 	log_debug("trying connect");
122 	if (connect(fd, (struct sockaddr *) &sa, SUN_LEN(&sa)) == -1) {
123 		log_debug("connect failed: %s", strerror(errno));
124 		if (errno != ECONNREFUSED && errno != ENOENT)
125 			goto failed;
126 		if (!start_server)
127 			goto failed;
128 		close(fd);
129 
130 		if (!locked) {
131 			xasprintf(&lockfile, "%s.lock", path);
132 			if ((lockfd = client_get_lock(lockfile)) == -1) {
133 				log_debug("didn't get lock");
134 				free(lockfile);
135 				goto retry;
136 			}
137 			log_debug("got lock");
138 
139 			/*
140 			 * Always retry at least once, even if we got the lock,
141 			 * because another client could have taken the lock,
142 			 * started the server and released the lock between our
143 			 * connect() and flock().
144 			 */
145 			locked = 1;
146 			goto retry;
147 		}
148 
149 		if (unlink(path) != 0 && errno != ENOENT) {
150 			free(lockfile);
151 			close(lockfd);
152 			return (-1);
153 		}
154 		fd = server_start(base, lockfd, lockfile);
155 	}
156 	if (locked) {
157 		free(lockfile);
158 		close(lockfd);
159 	}
160 
161 	setblocking(fd, 0);
162 	return (fd);
163 
164 failed:
165 	close(fd);
166 	return (-1);
167 }
168 
169 /* Get exit string from reason number. */
170 const char *
171 client_exit_message(void)
172 {
173 	static char msg[256];
174 
175 	switch (client_exitreason) {
176 	case CLIENT_EXIT_NONE:
177 		break;
178 	case CLIENT_EXIT_DETACHED:
179 		if (client_exitsession != NULL) {
180 			xsnprintf(msg, sizeof msg, "detached "
181 			    "(from session %s)", client_exitsession);
182 			return (msg);
183 		}
184 		return ("detached");
185 	case CLIENT_EXIT_DETACHED_HUP:
186 		if (client_exitsession != NULL) {
187 			xsnprintf(msg, sizeof msg, "detached and SIGHUP "
188 			    "(from session %s)", client_exitsession);
189 			return (msg);
190 		}
191 		return ("detached and SIGHUP");
192 	case CLIENT_EXIT_LOST_TTY:
193 		return ("lost tty");
194 	case CLIENT_EXIT_TERMINATED:
195 		return ("terminated");
196 	case CLIENT_EXIT_LOST_SERVER:
197 		return ("lost server");
198 	case CLIENT_EXIT_EXITED:
199 		return ("exited");
200 	case CLIENT_EXIT_SERVER_EXITED:
201 		return ("server exited");
202 	}
203 	return ("unknown reason");
204 }
205 
206 /* Client main loop. */
207 int
208 client_main(struct event_base *base, int argc, char **argv, int flags)
209 {
210 	struct cmd		*cmd;
211 	struct cmd_list		*cmdlist;
212 	struct msg_command_data	*data;
213 	int			 cmdflags, fd, i;
214 	pid_t			 ppid;
215 	enum msgtype		 msg;
216 	char			*cause;
217 	struct termios		 tio, saved_tio;
218 	size_t			 size;
219 
220 	/* Save the flags. */
221 	client_flags = flags;
222 
223 	/* Set up the initial command. */
224 	cmdflags = 0;
225 	if (shell_cmd != NULL) {
226 		msg = MSG_SHELL;
227 		cmdflags = CMD_STARTSERVER;
228 	} else if (argc == 0) {
229 		msg = MSG_COMMAND;
230 		cmdflags = CMD_STARTSERVER;
231 	} else {
232 		msg = MSG_COMMAND;
233 
234 		/*
235 		 * It sucks parsing the command string twice (in client and
236 		 * later in server) but it is necessary to get the start server
237 		 * flag.
238 		 */
239 		cmdlist = cmd_list_parse(argc, argv, NULL, 0, &cause);
240 		if (cmdlist == NULL) {
241 			fprintf(stderr, "%s\n", cause);
242 			return (1);
243 		}
244 		cmdflags &= ~CMD_STARTSERVER;
245 		TAILQ_FOREACH(cmd, &cmdlist->list, qentry) {
246 			if (cmd->entry->flags & CMD_STARTSERVER)
247 				cmdflags |= CMD_STARTSERVER;
248 		}
249 		cmd_list_free(cmdlist);
250 	}
251 
252 	/* Set process title, log and signals now this is the client. */
253 	setproctitle("client (%s)", socket_path);
254 	logfile("client");
255 
256 	/* Establish signal handlers. */
257 	set_signals(client_signal);
258 
259 	/* Initialize the client socket and start the server. */
260 	fd = client_connect(base, socket_path, cmdflags & CMD_STARTSERVER);
261 	if (fd == -1) {
262 		if (errno == ECONNREFUSED) {
263 			fprintf(stderr, "no server running on %s\n",
264 			    socket_path);
265 		} else {
266 			fprintf(stderr, "error connecting to %s (%s)\n",
267 			    socket_path, strerror(errno));
268 		}
269 		return (1);
270 	}
271 
272 	/* Create imsg. */
273 	imsg_init(&client_ibuf, fd);
274 	event_set(&client_event, fd, EV_READ, client_callback, NULL);
275 
276 	/* Create stdin handler. */
277 	setblocking(STDIN_FILENO, 0);
278 	event_set(&client_stdin, STDIN_FILENO, EV_READ|EV_PERSIST,
279 	    client_stdin_callback, NULL);
280 	if (client_flags & CLIENT_CONTROLCONTROL) {
281 		if (tcgetattr(STDIN_FILENO, &saved_tio) != 0) {
282 			fprintf(stderr, "tcgetattr failed: %s\n",
283 			    strerror(errno));
284 			return (1);
285 		}
286 		cfmakeraw(&tio);
287 		tio.c_iflag = ICRNL|IXANY;
288 		tio.c_oflag = OPOST|ONLCR;
289 		tio.c_lflag = NOKERNINFO;
290 		tio.c_cflag = CREAD|CS8|HUPCL;
291 		tio.c_cc[VMIN] = 1;
292 		tio.c_cc[VTIME] = 0;
293 		cfsetispeed(&tio, cfgetispeed(&saved_tio));
294 		cfsetospeed(&tio, cfgetospeed(&saved_tio));
295 		tcsetattr(STDIN_FILENO, TCSANOW, &tio);
296 	}
297 
298 	/* Send identify messages. */
299 	client_send_identify();
300 
301 	/* Send first command. */
302 	if (msg == MSG_COMMAND) {
303 		/* How big is the command? */
304 		size = 0;
305 		for (i = 0; i < argc; i++)
306 			size += strlen(argv[i]) + 1;
307 		data = xmalloc((sizeof *data) + size);
308 
309 		/* Prepare command for server. */
310 		data->argc = argc;
311 		if (cmd_pack_argv(argc, argv, (char *)(data + 1), size) != 0) {
312 			fprintf(stderr, "command too long\n");
313 			free(data);
314 			return (1);
315 		}
316 		size += sizeof *data;
317 
318 		/* Send the command. */
319 		if (client_write_server(msg, data, size) != 0) {
320 			fprintf(stderr, "failed to send command\n");
321 			free(data);
322 			return (1);
323 		}
324 		free(data);
325 	} else if (msg == MSG_SHELL)
326 		client_write_server(msg, NULL, 0);
327 
328 	/* Set the event and dispatch. */
329 	client_update_event();
330 	event_dispatch();
331 
332 	/* Print the exit message, if any, and exit. */
333 	if (client_attached) {
334 		if (client_exitreason != CLIENT_EXIT_NONE)
335 			printf("[%s]\n", client_exit_message());
336 
337 		ppid = getppid();
338 		if (client_exittype == MSG_DETACHKILL && ppid > 1)
339 			kill(ppid, SIGHUP);
340 	} else if (client_flags & CLIENT_CONTROLCONTROL) {
341 		if (client_exitreason != CLIENT_EXIT_NONE)
342 			printf("%%exit %s\n", client_exit_message());
343 		else
344 			printf("%%exit\n");
345 		printf("\033\\");
346 		tcsetattr(STDOUT_FILENO, TCSAFLUSH, &saved_tio);
347 	}
348 	setblocking(STDIN_FILENO, 1);
349 	return (client_exitval);
350 }
351 
352 /* Send identify messages to server. */
353 void
354 client_send_identify(void)
355 {
356 	const char	 *s;
357 	char		**ss;
358 	size_t		  sslen;
359 	int		  fd, flags = client_flags;
360 	pid_t		  pid;
361 
362 	client_write_one(MSG_IDENTIFY_FLAGS, -1, &flags, sizeof flags);
363 
364 	if ((s = getenv("TERM")) == NULL)
365 		s = "";
366 	client_write_one(MSG_IDENTIFY_TERM, -1, s, strlen(s) + 1);
367 
368 	if ((s = ttyname(STDIN_FILENO)) == NULL)
369 		s = "";
370 	client_write_one(MSG_IDENTIFY_TTYNAME, -1, s, strlen(s) + 1);
371 
372 	if ((fd = open(".", O_RDONLY)) == -1)
373 		fd = open("/", O_RDONLY);
374 	client_write_one(MSG_IDENTIFY_CWD, fd, NULL, 0);
375 
376 	if ((fd = dup(STDIN_FILENO)) == -1)
377 		fatal("dup failed");
378 	client_write_one(MSG_IDENTIFY_STDIN, fd, NULL, 0);
379 
380 	pid = getpid();
381 	client_write_one(MSG_IDENTIFY_CLIENTPID, -1, &pid, sizeof pid);
382 
383 	for (ss = environ; *ss != NULL; ss++) {
384 		sslen = strlen(*ss) + 1;
385 		if (sslen <= MAX_IMSGSIZE - IMSG_HEADER_SIZE)
386 			client_write_one(MSG_IDENTIFY_ENVIRON, -1, *ss, sslen);
387 	}
388 
389 	client_write_one(MSG_IDENTIFY_DONE, -1, NULL, 0);
390 
391 	client_update_event();
392 }
393 
394 /* Helper to send one message. */
395 int
396 client_write_one(enum msgtype type, int fd, const void *buf, size_t len)
397 {
398 	int	retval;
399 
400 	retval = imsg_compose(&client_ibuf, type, PROTOCOL_VERSION, -1, fd,
401 	    (void *)buf, len);
402 	if (retval != 1)
403 		return (-1);
404 	return (0);
405 }
406 
407 /* Write a message to the server without a file descriptor. */
408 int
409 client_write_server(enum msgtype type, const void *buf, size_t len)
410 {
411 	int	retval;
412 
413 	retval = client_write_one(type, -1, buf, len);
414 	if (retval == 0)
415 		client_update_event();
416 	return (retval);
417 }
418 
419 /* Update client event based on whether it needs to read or read and write. */
420 void
421 client_update_event(void)
422 {
423 	short	events;
424 
425 	event_del(&client_event);
426 	events = EV_READ;
427 	if (client_ibuf.w.queued > 0)
428 		events |= EV_WRITE;
429 	event_set(&client_event, client_ibuf.fd, events, client_callback, NULL);
430 	event_add(&client_event, NULL);
431 }
432 
433 /* Callback to handle signals in the client. */
434 void
435 client_signal(int sig, unused short events, unused void *arg)
436 {
437 	struct sigaction sigact;
438 	int		 status;
439 
440 	if (sig == SIGCHLD)
441 		waitpid(WAIT_ANY, &status, WNOHANG);
442 	else if (!client_attached) {
443 		if (sig == SIGTERM)
444 			event_loopexit(NULL);
445 	} else {
446 		switch (sig) {
447 		case SIGHUP:
448 			client_exitreason = CLIENT_EXIT_LOST_TTY;
449 			client_exitval = 1;
450 			client_write_server(MSG_EXITING, NULL, 0);
451 			break;
452 		case SIGTERM:
453 			client_exitreason = CLIENT_EXIT_TERMINATED;
454 			client_exitval = 1;
455 			client_write_server(MSG_EXITING, NULL, 0);
456 			break;
457 		case SIGWINCH:
458 			client_write_server(MSG_RESIZE, NULL, 0);
459 			break;
460 		case SIGCONT:
461 			memset(&sigact, 0, sizeof sigact);
462 			sigemptyset(&sigact.sa_mask);
463 			sigact.sa_flags = SA_RESTART;
464 			sigact.sa_handler = SIG_IGN;
465 			if (sigaction(SIGTSTP, &sigact, NULL) != 0)
466 				fatal("sigaction failed");
467 			client_write_server(MSG_WAKEUP, NULL, 0);
468 			break;
469 		}
470 	}
471 
472 	client_update_event();
473 }
474 
475 /* Callback for client imsg read events. */
476 void
477 client_callback(unused int fd, short events, unused void *arg)
478 {
479 	ssize_t	n;
480 	int	retval;
481 
482 	if (events & EV_READ) {
483 		if ((n = imsg_read(&client_ibuf)) == -1 || n == 0)
484 			goto lost_server;
485 		if (client_attached)
486 			retval = client_dispatch_attached();
487 		else
488 			retval = client_dispatch_wait();
489 		if (retval != 0) {
490 			event_loopexit(NULL);
491 			return;
492 		}
493 	}
494 
495 	if (events & EV_WRITE) {
496 		if (msgbuf_write(&client_ibuf.w) <= 0 && errno != EAGAIN)
497 			goto lost_server;
498 	}
499 
500 	client_update_event();
501 	return;
502 
503 lost_server:
504 	client_exitreason = CLIENT_EXIT_LOST_SERVER;
505 	client_exitval = 1;
506 	event_loopexit(NULL);
507 }
508 
509 /* Callback for client stdin read events. */
510 void
511 client_stdin_callback(unused int fd, unused short events, unused void *arg)
512 {
513 	struct msg_stdin_data	data;
514 
515 	data.size = read(STDIN_FILENO, data.data, sizeof data.data);
516 	if (data.size < 0 && (errno == EINTR || errno == EAGAIN))
517 		return;
518 
519 	client_write_server(MSG_STDIN, &data, sizeof data);
520 	if (data.size <= 0)
521 		event_del(&client_stdin);
522 	client_update_event();
523 }
524 
525 /* Force write to file descriptor. */
526 void
527 client_write(int fd, const char *data, size_t size)
528 {
529 	ssize_t	used;
530 
531 	while (size != 0) {
532 		used = write(fd, data, size);
533 		if (used == -1) {
534 			if (errno == EINTR || errno == EAGAIN)
535 				continue;
536 			break;
537 		}
538 		data += used;
539 		size -= used;
540 	}
541 }
542 
543 /* Run command in shell; used for -c. */
544 __dead void
545 client_exec(const char *shell)
546 {
547 	const char	*name, *ptr;
548 	char		*argv0;
549 
550 	log_debug("shell %s, command %s", shell, shell_cmd);
551 
552 	ptr = strrchr(shell, '/');
553 	if (ptr != NULL && *(ptr + 1) != '\0')
554 		name = ptr + 1;
555 	else
556 		name = shell;
557 	if (client_flags & CLIENT_LOGIN)
558 		xasprintf(&argv0, "-%s", name);
559 	else
560 		xasprintf(&argv0, "%s", name);
561 	setenv("SHELL", shell, 1);
562 
563 	setblocking(STDIN_FILENO, 1);
564 	setblocking(STDOUT_FILENO, 1);
565 	setblocking(STDERR_FILENO, 1);
566 	closefrom(STDERR_FILENO + 1);
567 
568 	execl(shell, argv0, "-c", shell_cmd, (char *) NULL);
569 	fatal("execl failed");
570 }
571 
572 /* Dispatch imsgs when in wait state (before MSG_READY). */
573 int
574 client_dispatch_wait(void)
575 {
576 	struct imsg		 imsg;
577 	char			*data;
578 	ssize_t			 n, datalen;
579 	struct msg_stdout_data	 stdoutdata;
580 	struct msg_stderr_data	 stderrdata;
581 	int			 retval;
582 
583 	for (;;) {
584 		if ((n = imsg_get(&client_ibuf, &imsg)) == -1)
585 			fatalx("imsg_get failed");
586 		if (n == 0)
587 			return (0);
588 
589 		data = imsg.data;
590 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
591 
592 		log_debug("got %u from server", imsg.hdr.type);
593 		switch (imsg.hdr.type) {
594 		case MSG_EXIT:
595 		case MSG_SHUTDOWN:
596 			if (datalen != sizeof retval && datalen != 0)
597 				fatalx("bad MSG_EXIT size");
598 			if (datalen == sizeof retval) {
599 				memcpy(&retval, data, sizeof retval);
600 				client_exitval = retval;
601 			}
602 			imsg_free(&imsg);
603 			return (-1);
604 		case MSG_READY:
605 			if (datalen != 0)
606 				fatalx("bad MSG_READY size");
607 
608 			event_del(&client_stdin);
609 			client_attached = 1;
610 			client_write_server(MSG_RESIZE, NULL, 0);
611 			break;
612 		case MSG_STDIN:
613 			if (datalen != 0)
614 				fatalx("bad MSG_STDIN size");
615 
616 			event_add(&client_stdin, NULL);
617 			break;
618 		case MSG_STDOUT:
619 			if (datalen != sizeof stdoutdata)
620 				fatalx("bad MSG_STDOUT size");
621 			memcpy(&stdoutdata, data, sizeof stdoutdata);
622 
623 			client_write(STDOUT_FILENO, stdoutdata.data,
624 			    stdoutdata.size);
625 			break;
626 		case MSG_STDERR:
627 			if (datalen != sizeof stderrdata)
628 				fatalx("bad MSG_STDERR size");
629 			memcpy(&stderrdata, data, sizeof stderrdata);
630 
631 			client_write(STDERR_FILENO, stderrdata.data,
632 			    stderrdata.size);
633 			break;
634 		case MSG_VERSION:
635 			if (datalen != 0)
636 				fatalx("bad MSG_VERSION size");
637 
638 			fprintf(stderr, "protocol version mismatch "
639 			    "(client %d, server %u)\n", PROTOCOL_VERSION,
640 			    imsg.hdr.peerid);
641 			client_exitval = 1;
642 
643 			imsg_free(&imsg);
644 			return (-1);
645 		case MSG_SHELL:
646 			if (datalen == 0 || data[datalen - 1] != '\0')
647 				fatalx("bad MSG_SHELL string");
648 
649 			clear_signals(0);
650 			client_exec(data);
651 			/* NOTREACHED */
652 		case MSG_DETACH:
653 		case MSG_DETACHKILL:
654 			client_write_server(MSG_EXITING, NULL, 0);
655 			break;
656 		case MSG_EXITED:
657 			imsg_free(&imsg);
658 			return (-1);
659 		}
660 
661 		imsg_free(&imsg);
662 	}
663 }
664 
665 /* Dispatch imsgs in attached state (after MSG_READY). */
666 int
667 client_dispatch_attached(void)
668 {
669 	struct imsg		 imsg;
670 	struct sigaction	 sigact;
671 	char			*data;
672 	ssize_t			 n, datalen;
673 
674 	for (;;) {
675 		if ((n = imsg_get(&client_ibuf, &imsg)) == -1)
676 			fatalx("imsg_get failed");
677 		if (n == 0)
678 			return (0);
679 
680 		data = imsg.data;
681 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
682 
683 		log_debug("got %u from server", imsg.hdr.type);
684 		switch (imsg.hdr.type) {
685 		case MSG_DETACH:
686 		case MSG_DETACHKILL:
687 			if (datalen == 0 || data[datalen - 1] != '\0')
688 				fatalx("bad MSG_DETACH string");
689 
690 			client_exitsession = xstrdup(data);
691 			client_exittype = imsg.hdr.type;
692 			if (imsg.hdr.type == MSG_DETACHKILL)
693 				client_exitreason = CLIENT_EXIT_DETACHED_HUP;
694 			else
695 				client_exitreason = CLIENT_EXIT_DETACHED;
696 			client_write_server(MSG_EXITING, NULL, 0);
697 			break;
698 		case MSG_EXIT:
699 			if (datalen != 0 && datalen != sizeof (int))
700 				fatalx("bad MSG_EXIT size");
701 
702 			client_write_server(MSG_EXITING, NULL, 0);
703 			client_exitreason = CLIENT_EXIT_EXITED;
704 			break;
705 		case MSG_EXITED:
706 			if (datalen != 0)
707 				fatalx("bad MSG_EXITED size");
708 
709 			imsg_free(&imsg);
710 			return (-1);
711 		case MSG_SHUTDOWN:
712 			if (datalen != 0)
713 				fatalx("bad MSG_SHUTDOWN size");
714 
715 			client_write_server(MSG_EXITING, NULL, 0);
716 			client_exitreason = CLIENT_EXIT_SERVER_EXITED;
717 			client_exitval = 1;
718 			break;
719 		case MSG_SUSPEND:
720 			if (datalen != 0)
721 				fatalx("bad MSG_SUSPEND size");
722 
723 			memset(&sigact, 0, sizeof sigact);
724 			sigemptyset(&sigact.sa_mask);
725 			sigact.sa_flags = SA_RESTART;
726 			sigact.sa_handler = SIG_DFL;
727 			if (sigaction(SIGTSTP, &sigact, NULL) != 0)
728 				fatal("sigaction failed");
729 			kill(getpid(), SIGTSTP);
730 			break;
731 		case MSG_LOCK:
732 			if (datalen == 0 || data[datalen - 1] != '\0')
733 				fatalx("bad MSG_LOCK string");
734 
735 			system(data);
736 			client_write_server(MSG_UNLOCK, NULL, 0);
737 			break;
738 		}
739 
740 		imsg_free(&imsg);
741 	}
742 }
743