xref: /netbsd-src/external/bsd/tmux/dist/client.c (revision bdc22b2e01993381dcefeff2bc9b56ca75a4235c)
1 /* $OpenBSD$ */
2 
3 /*
4  * Copyright (c) 2007 Nicholas Marriott <nicholas.marriott@gmail.com>
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 static struct tmuxproc	*client_proc;
37 static struct tmuxpeer	*client_peer;
38 static int		 client_flags;
39 static struct event	 client_stdin;
40 static 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 static int		 client_exitval;
51 static enum msgtype	 client_exittype;
52 static const char	*client_exitsession;
53 static const char	*client_execshell;
54 static const char	*client_execcmd;
55 static int		 client_attached;
56 
57 static __dead void	 client_exec(const char *,const char *);
58 static int		 client_get_lock(char *);
59 static int		 client_connect(struct event_base *, const char *, int);
60 static void		 client_send_identify(const char *, const char *);
61 static void		 client_stdin_callback(int, short, void *);
62 static void		 client_write(int, const char *, size_t);
63 static void		 client_signal(int);
64 static void		 client_dispatch(struct imsg *, void *);
65 static void		 client_dispatch_attached(struct imsg *);
66 static void		 client_dispatch_wait(struct imsg *);
67 static const char	*client_exit_message(void);
68 
69 /*
70  * Get server create lock. If already held then server start is happening in
71  * another client, so block until the lock is released and return -2 to
72  * retry. Return -1 on failure to continue and start the server anyway.
73  */
74 static int
75 client_get_lock(char *lockfile)
76 {
77 	int lockfd;
78 
79 	log_debug("lock file is %s", lockfile);
80 
81 	if ((lockfd = open(lockfile, O_WRONLY|O_CREAT, 0600)) == -1) {
82 		log_debug("open failed: %s", strerror(errno));
83 		return (-1);
84 	}
85 
86 	if (flock(lockfd, LOCK_EX|LOCK_NB) == -1) {
87 		log_debug("flock failed: %s", strerror(errno));
88 		if (errno != EAGAIN)
89 			return (lockfd);
90 		while (flock(lockfd, LOCK_EX) == -1 && errno == EINTR)
91 			/* nothing */;
92 		close(lockfd);
93 		return (-2);
94 	}
95 	log_debug("flock succeeded");
96 
97 	return (lockfd);
98 }
99 
100 /* Connect client to server. */
101 static int
102 client_connect(struct event_base *base, const char *path, int start_server)
103 {
104 	struct sockaddr_un	sa;
105 	size_t			size;
106 	int			fd, lockfd = -1, locked = 0;
107 	char		       *lockfile = NULL;
108 
109 	memset(&sa, 0, sizeof sa);
110 	sa.sun_family = AF_UNIX;
111 	size = strlcpy(sa.sun_path, path, sizeof sa.sun_path);
112 	if (size >= sizeof sa.sun_path) {
113 		errno = ENAMETOOLONG;
114 		return (-1);
115 	}
116 	log_debug("socket is %s", path);
117 
118 retry:
119 	if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1)
120 		return (-1);
121 
122 	log_debug("trying connect");
123 	if (connect(fd, (struct sockaddr *)&sa, sizeof sa) == -1) {
124 		log_debug("connect failed: %s", strerror(errno));
125 		if (errno != ECONNREFUSED && errno != ENOENT)
126 			goto failed;
127 		if (!start_server)
128 			goto failed;
129 		close(fd);
130 
131 		if (!locked) {
132 			xasprintf(&lockfile, "%s.lock", path);
133 			if ((lockfd = client_get_lock(lockfile)) < 0) {
134 				log_debug("didn't get lock (%d)", lockfd);
135 
136 				free(lockfile);
137 				lockfile = NULL;
138 
139 				if (lockfd == -2)
140 					goto retry;
141 			}
142 			log_debug("got lock (%d)", lockfd);
143 
144 			/*
145 			 * Always retry at least once, even if we got the lock,
146 			 * because another client could have taken the lock,
147 			 * started the server and released the lock between our
148 			 * connect() and flock().
149 			 */
150 			locked = 1;
151 			goto retry;
152 		}
153 
154 		if (lockfd >= 0 && unlink(path) != 0 && errno != ENOENT) {
155 			free(lockfile);
156 			close(lockfd);
157 			return (-1);
158 		}
159 		fd = server_start(client_proc, base, lockfd, lockfile);
160 	}
161 
162 	if (locked && lockfd >= 0) {
163 		free(lockfile);
164 		close(lockfd);
165 	}
166 	setblocking(fd, 0);
167 	return (fd);
168 
169 failed:
170 	if (locked) {
171 		free(lockfile);
172 		close(lockfd);
173 	}
174 	close(fd);
175 	return (-1);
176 }
177 
178 /* Get exit string from reason number. */
179 const char *
180 client_exit_message(void)
181 {
182 	static char msg[256];
183 
184 	switch (client_exitreason) {
185 	case CLIENT_EXIT_NONE:
186 		break;
187 	case CLIENT_EXIT_DETACHED:
188 		if (client_exitsession != NULL) {
189 			xsnprintf(msg, sizeof msg, "detached "
190 			    "(from session %s)", client_exitsession);
191 			return (msg);
192 		}
193 		return ("detached");
194 	case CLIENT_EXIT_DETACHED_HUP:
195 		if (client_exitsession != NULL) {
196 			xsnprintf(msg, sizeof msg, "detached and SIGHUP "
197 			    "(from session %s)", client_exitsession);
198 			return (msg);
199 		}
200 		return ("detached and SIGHUP");
201 	case CLIENT_EXIT_LOST_TTY:
202 		return ("lost tty");
203 	case CLIENT_EXIT_TERMINATED:
204 		return ("terminated");
205 	case CLIENT_EXIT_LOST_SERVER:
206 		return ("lost server");
207 	case CLIENT_EXIT_EXITED:
208 		return ("exited");
209 	case CLIENT_EXIT_SERVER_EXITED:
210 		return ("server exited");
211 	}
212 	return ("unknown reason");
213 }
214 
215 /* Client main loop. */
216 int
217 client_main(struct event_base *base, int argc, char **argv, int flags)
218 {
219 	struct cmd		*cmd;
220 	struct cmd_list		*cmdlist;
221 	struct msg_command_data	*data;
222 	int			 cmdflags, fd, i;
223 	const char		*ttynam, *cwd;
224 	pid_t			 ppid;
225 	enum msgtype		 msg;
226 	char			*cause, path[PATH_MAX];
227 	struct termios		 tio, saved_tio;
228 	size_t			 size;
229 
230 	/* Ignore SIGCHLD now or daemon() in the server will leave a zombie. */
231 	signal(SIGCHLD, SIG_IGN);
232 
233 	/* Save the flags. */
234 	client_flags = flags;
235 
236 	/* Set up the initial command. */
237 	cmdflags = 0;
238 	if (shell_command != NULL) {
239 		msg = MSG_SHELL;
240 		cmdflags = CMD_STARTSERVER;
241 	} else if (argc == 0) {
242 		msg = MSG_COMMAND;
243 		cmdflags = CMD_STARTSERVER;
244 	} else {
245 		msg = MSG_COMMAND;
246 
247 		/*
248 		 * It sucks parsing the command string twice (in client and
249 		 * later in server) but it is necessary to get the start server
250 		 * flag.
251 		 */
252 		cmdlist = cmd_list_parse(argc, argv, NULL, 0, &cause);
253 		if (cmdlist != NULL) {
254 			TAILQ_FOREACH(cmd, &cmdlist->list, qentry) {
255 				if (cmd->entry->flags & CMD_STARTSERVER)
256 					cmdflags |= CMD_STARTSERVER;
257 			}
258 			cmd_list_free(cmdlist);
259 		}
260 	}
261 
262 	/* Create client process structure (starts logging). */
263 	client_proc = proc_start("client");
264 	proc_set_signals(client_proc, client_signal);
265 
266 	/* Initialize the client socket and start the server. */
267 	fd = client_connect(base, socket_path, cmdflags & CMD_STARTSERVER);
268 	if (fd == -1) {
269 		if (errno == ECONNREFUSED) {
270 			fprintf(stderr, "no server running on %s\n",
271 			    socket_path);
272 		} else {
273 			fprintf(stderr, "error connecting to %s (%s)\n",
274 			    socket_path, strerror(errno));
275 		}
276 		return (1);
277 	}
278 	client_peer = proc_add_peer(client_proc, fd, client_dispatch, NULL);
279 
280 	/* Save these before pledge(). */
281 	if ((cwd = getcwd(path, sizeof path)) == NULL) {
282 		if ((cwd = find_home()) == NULL)
283 			cwd = "/";
284 	}
285 	if ((ttynam = ttyname(STDIN_FILENO)) == NULL)
286 		ttynam = "";
287 
288 	/*
289 	 * Drop privileges for client. "proc exec" is needed for -c and for
290 	 * locking (which uses system(3)).
291 	 *
292 	 * "tty" is needed to restore termios(4) and also for some reason -CC
293 	 * does not work properly without it (input is not recognised).
294 	 *
295 	 * "sendfd" is dropped later in client_dispatch_wait().
296 	 */
297 	if (pledge("stdio unix sendfd proc exec tty", NULL) != 0)
298 		fatal("pledge failed");
299 
300 	/* Free stuff that is not used in the client. */
301 	if (ptm_fd != -1)
302 		close(ptm_fd);
303 	options_free(global_options);
304 	options_free(global_s_options);
305 	options_free(global_w_options);
306 	environ_free(global_environ);
307 
308 	/* Create stdin handler. */
309 	setblocking(STDIN_FILENO, 0);
310 	event_set(&client_stdin, STDIN_FILENO, EV_READ|EV_PERSIST,
311 	    client_stdin_callback, NULL);
312 	if (client_flags & CLIENT_CONTROLCONTROL) {
313 		if (tcgetattr(STDIN_FILENO, &saved_tio) != 0) {
314 			fprintf(stderr, "tcgetattr failed: %s\n",
315 			    strerror(errno));
316 			return (1);
317 		}
318 		cfmakeraw(&tio);
319 		tio.c_iflag = ICRNL|IXANY;
320 		tio.c_oflag = OPOST|ONLCR;
321 #ifdef NOKERNINFO
322 		tio.c_lflag = NOKERNINFO;
323 #endif
324 		tio.c_cflag = CREAD|CS8|HUPCL;
325 		tio.c_cc[VMIN] = 1;
326 		tio.c_cc[VTIME] = 0;
327 		cfsetispeed(&tio, cfgetispeed(&saved_tio));
328 		cfsetospeed(&tio, cfgetospeed(&saved_tio));
329 		tcsetattr(STDIN_FILENO, TCSANOW, &tio);
330 	}
331 
332 	/* Send identify messages. */
333 	client_send_identify(ttynam, cwd);
334 
335 	/* Send first command. */
336 	if (msg == MSG_COMMAND) {
337 		/* How big is the command? */
338 		size = 0;
339 		for (i = 0; i < argc; i++)
340 			size += strlen(argv[i]) + 1;
341 		data = xmalloc((sizeof *data) + size);
342 
343 		/* Prepare command for server. */
344 		data->argc = argc;
345 		if (cmd_pack_argv(argc, argv, (char *)(data + 1), size) != 0) {
346 			fprintf(stderr, "command too long\n");
347 			free(data);
348 			return (1);
349 		}
350 		size += sizeof *data;
351 
352 		/* Send the command. */
353 		if (proc_send(client_peer, msg, -1, data, size) != 0) {
354 			fprintf(stderr, "failed to send command\n");
355 			free(data);
356 			return (1);
357 		}
358 		free(data);
359 	} else if (msg == MSG_SHELL)
360 		proc_send(client_peer, msg, -1, NULL, 0);
361 
362 	/* Start main loop. */
363 	proc_loop(client_proc, NULL);
364 
365 	/* Run command if user requested exec, instead of exiting. */
366 	if (client_exittype == MSG_EXEC) {
367 		if (client_flags & CLIENT_CONTROLCONTROL)
368 			tcsetattr(STDOUT_FILENO, TCSAFLUSH, &saved_tio);
369 		client_exec(client_execshell, client_execcmd);
370 	}
371 
372 	/* Print the exit message, if any, and exit. */
373 	if (client_attached) {
374 		if (client_exitreason != CLIENT_EXIT_NONE)
375 			printf("[%s]\n", client_exit_message());
376 
377 		ppid = getppid();
378 		if (client_exittype == MSG_DETACHKILL && ppid > 1)
379 			kill(ppid, SIGHUP);
380 	} else if (client_flags & CLIENT_CONTROLCONTROL) {
381 		if (client_exitreason != CLIENT_EXIT_NONE)
382 			printf("%%exit %s\n", client_exit_message());
383 		else
384 			printf("%%exit\n");
385 		printf("\033\\");
386 		tcsetattr(STDOUT_FILENO, TCSAFLUSH, &saved_tio);
387 	} else if (client_exitreason != CLIENT_EXIT_NONE)
388 		fprintf(stderr, "%s\n", client_exit_message());
389 	setblocking(STDIN_FILENO, 1);
390 	return (client_exitval);
391 }
392 
393 /* Send identify messages to server. */
394 static void
395 client_send_identify(const char *ttynam, const char *cwd)
396 {
397 	const char	 *s;
398 	char		**ss;
399 	size_t		  sslen;
400 	int		  fd, flags = client_flags;
401 	pid_t		  pid;
402 
403 	proc_send(client_peer, MSG_IDENTIFY_FLAGS, -1, &flags, sizeof flags);
404 
405 	if ((s = getenv("TERM")) == NULL)
406 		s = "";
407 	proc_send(client_peer, MSG_IDENTIFY_TERM, -1, s, strlen(s) + 1);
408 
409 	proc_send(client_peer, MSG_IDENTIFY_TTYNAME, -1, ttynam,
410 	    strlen(ttynam) + 1);
411 	proc_send(client_peer, MSG_IDENTIFY_CWD, -1, cwd, strlen(cwd) + 1);
412 
413 	if ((fd = dup(STDIN_FILENO)) == -1)
414 		fatal("dup failed");
415 	proc_send(client_peer, MSG_IDENTIFY_STDIN, fd, NULL, 0);
416 
417 	pid = getpid();
418 	proc_send(client_peer, MSG_IDENTIFY_CLIENTPID, -1, &pid, sizeof pid);
419 
420 	for (ss = environ; *ss != NULL; ss++) {
421 		sslen = strlen(*ss) + 1;
422 		if (sslen > MAX_IMSGSIZE - IMSG_HEADER_SIZE)
423 			continue;
424 		proc_send(client_peer, MSG_IDENTIFY_ENVIRON, -1, *ss, sslen);
425 	}
426 
427 	proc_send(client_peer, MSG_IDENTIFY_DONE, -1, NULL, 0);
428 }
429 
430 /* Callback for client stdin read events. */
431 static void
432 client_stdin_callback(__unused int fd, __unused short events,
433     __unused void *arg)
434 {
435 	struct msg_stdin_data	data;
436 
437 	data.size = read(STDIN_FILENO, data.data, sizeof data.data);
438 	if (data.size < 0 && (errno == EINTR || errno == EAGAIN))
439 		return;
440 
441 	proc_send(client_peer, MSG_STDIN, -1, &data, sizeof data);
442 	if (data.size <= 0)
443 		event_del(&client_stdin);
444 }
445 
446 /* Force write to file descriptor. */
447 static void
448 client_write(int fd, const char *data, size_t size)
449 {
450 	ssize_t	used;
451 
452 	while (size != 0) {
453 		used = write(fd, data, size);
454 		if (used == -1) {
455 			if (errno == EINTR || errno == EAGAIN)
456 				continue;
457 			break;
458 		}
459 		data += used;
460 		size -= used;
461 	}
462 }
463 
464 /* Run command in shell; used for -c. */
465 static __dead void
466 client_exec(const char *shell, const char *shellcmd)
467 {
468 	const char	*name, *ptr;
469 	char		*argv0;
470 
471 	log_debug("shell %s, command %s", shell, shellcmd);
472 
473 	ptr = strrchr(shell, '/');
474 	if (ptr != NULL && *(ptr + 1) != '\0')
475 		name = ptr + 1;
476 	else
477 		name = shell;
478 	if (client_flags & CLIENT_LOGIN)
479 		xasprintf(&argv0, "-%s", name);
480 	else
481 		xasprintf(&argv0, "%s", name);
482 	setenv("SHELL", shell, 1);
483 
484 	proc_clear_signals(client_proc, 1);
485 
486 	setblocking(STDIN_FILENO, 1);
487 	setblocking(STDOUT_FILENO, 1);
488 	setblocking(STDERR_FILENO, 1);
489 	closefrom(STDERR_FILENO + 1);
490 
491 	execl(shell, argv0, "-c", shellcmd, (char *) NULL);
492 	fatal("execl failed");
493 }
494 
495 /* Callback to handle signals in the client. */
496 static void
497 client_signal(int sig)
498 {
499 	struct sigaction sigact;
500 	int		 status;
501 
502 	if (sig == SIGCHLD)
503 		waitpid(WAIT_ANY, &status, WNOHANG);
504 	else if (!client_attached) {
505 		if (sig == SIGTERM)
506 			proc_exit(client_proc);
507 	} else {
508 		switch (sig) {
509 		case SIGHUP:
510 			client_exitreason = CLIENT_EXIT_LOST_TTY;
511 			client_exitval = 1;
512 			proc_send(client_peer, MSG_EXITING, -1, NULL, 0);
513 			break;
514 		case SIGTERM:
515 			client_exitreason = CLIENT_EXIT_TERMINATED;
516 			client_exitval = 1;
517 			proc_send(client_peer, MSG_EXITING, -1, NULL, 0);
518 			break;
519 		case SIGWINCH:
520 			proc_send(client_peer, MSG_RESIZE, -1, NULL, 0);
521 			break;
522 		case SIGCONT:
523 			memset(&sigact, 0, sizeof sigact);
524 			sigemptyset(&sigact.sa_mask);
525 			sigact.sa_flags = SA_RESTART;
526 			sigact.sa_handler = SIG_IGN;
527 			if (sigaction(SIGTSTP, &sigact, NULL) != 0)
528 				fatal("sigaction failed");
529 			proc_send(client_peer, MSG_WAKEUP, -1, NULL, 0);
530 			break;
531 		}
532 	}
533 }
534 
535 /* Callback for client read events. */
536 static void
537 client_dispatch(struct imsg *imsg, __unused void *arg)
538 {
539 	if (imsg == NULL) {
540 		client_exitreason = CLIENT_EXIT_LOST_SERVER;
541 		client_exitval = 1;
542 		proc_exit(client_proc);
543 		return;
544 	}
545 
546 	if (client_attached)
547 		client_dispatch_attached(imsg);
548 	else
549 		client_dispatch_wait(imsg);
550 }
551 
552 /* Dispatch imsgs when in wait state (before MSG_READY). */
553 static void
554 client_dispatch_wait(struct imsg *imsg)
555 {
556 	char			*data;
557 	ssize_t			 datalen;
558 	struct msg_stdout_data	 stdoutdata;
559 	struct msg_stderr_data	 stderrdata;
560 	int			 retval;
561 	static int		 pledge_applied;
562 
563 	/*
564 	 * "sendfd" is no longer required once all of the identify messages
565 	 * have been sent. We know the server won't send us anything until that
566 	 * point (because we don't ask it to), so we can drop "sendfd" once we
567 	 * get the first message from the server.
568 	 */
569 	if (!pledge_applied) {
570 		if (pledge("stdio unix proc exec tty", NULL) != 0)
571 			fatal("pledge failed");
572 		pledge_applied = 1;
573 	};
574 
575 	data = imsg->data;
576 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
577 
578 	switch (imsg->hdr.type) {
579 	case MSG_EXIT:
580 	case MSG_SHUTDOWN:
581 		if (datalen != sizeof retval && datalen != 0)
582 			fatalx("bad MSG_EXIT size");
583 		if (datalen == sizeof retval) {
584 			memcpy(&retval, data, sizeof retval);
585 			client_exitval = retval;
586 		}
587 		proc_exit(client_proc);
588 		break;
589 	case MSG_READY:
590 		if (datalen != 0)
591 			fatalx("bad MSG_READY size");
592 
593 		event_del(&client_stdin);
594 		client_attached = 1;
595 		proc_send(client_peer, MSG_RESIZE, -1, NULL, 0);
596 		break;
597 	case MSG_STDIN:
598 		if (datalen != 0)
599 			fatalx("bad MSG_STDIN size");
600 
601 		event_add(&client_stdin, NULL);
602 		break;
603 	case MSG_STDOUT:
604 		if (datalen != sizeof stdoutdata)
605 			fatalx("bad MSG_STDOUT size");
606 		memcpy(&stdoutdata, data, sizeof stdoutdata);
607 
608 		client_write(STDOUT_FILENO, stdoutdata.data,
609 		    stdoutdata.size);
610 		break;
611 	case MSG_STDERR:
612 		if (datalen != sizeof stderrdata)
613 			fatalx("bad MSG_STDERR size");
614 		memcpy(&stderrdata, data, sizeof stderrdata);
615 
616 		client_write(STDERR_FILENO, stderrdata.data,
617 		    stderrdata.size);
618 		break;
619 	case MSG_VERSION:
620 		if (datalen != 0)
621 			fatalx("bad MSG_VERSION size");
622 
623 		fprintf(stderr, "protocol version mismatch "
624 		    "(client %d, server %u)\n", PROTOCOL_VERSION,
625 		    imsg->hdr.peerid & 0xff);
626 		client_exitval = 1;
627 		proc_exit(client_proc);
628 		break;
629 	case MSG_SHELL:
630 		if (datalen == 0 || data[datalen - 1] != '\0')
631 			fatalx("bad MSG_SHELL string");
632 
633 		client_exec(data, shell_command);
634 		/* NOTREACHED */
635 	case MSG_DETACH:
636 	case MSG_DETACHKILL:
637 		proc_send(client_peer, MSG_EXITING, -1, NULL, 0);
638 		break;
639 	case MSG_EXITED:
640 		proc_exit(client_proc);
641 		break;
642 	}
643 }
644 
645 /* Dispatch imsgs in attached state (after MSG_READY). */
646 static void
647 client_dispatch_attached(struct imsg *imsg)
648 {
649 	struct sigaction	 sigact;
650 	char			*data;
651 	ssize_t			 datalen;
652 
653 	data = imsg->data;
654 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
655 
656 	switch (imsg->hdr.type) {
657 	case MSG_DETACH:
658 	case MSG_DETACHKILL:
659 		if (datalen == 0 || data[datalen - 1] != '\0')
660 			fatalx("bad MSG_DETACH string");
661 
662 		client_exitsession = xstrdup(data);
663 		client_exittype = imsg->hdr.type;
664 		if (imsg->hdr.type == MSG_DETACHKILL)
665 			client_exitreason = CLIENT_EXIT_DETACHED_HUP;
666 		else
667 			client_exitreason = CLIENT_EXIT_DETACHED;
668 		proc_send(client_peer, MSG_EXITING, -1, NULL, 0);
669 		break;
670 	case MSG_EXEC:
671 		if (datalen == 0 || data[datalen - 1] != '\0' ||
672 		    strlen(data) + 1 == (size_t)datalen)
673 			fatalx("bad MSG_EXEC string");
674 		client_execcmd = xstrdup(data);
675 		client_execshell = xstrdup(data + strlen(data) + 1);
676 
677 		client_exittype = imsg->hdr.type;
678 		proc_send(client_peer, MSG_EXITING, -1, NULL, 0);
679 		break;
680 	case MSG_EXIT:
681 		if (datalen != 0 && datalen != sizeof (int))
682 			fatalx("bad MSG_EXIT size");
683 
684 		proc_send(client_peer, MSG_EXITING, -1, NULL, 0);
685 		client_exitreason = CLIENT_EXIT_EXITED;
686 		break;
687 	case MSG_EXITED:
688 		if (datalen != 0)
689 			fatalx("bad MSG_EXITED size");
690 
691 		proc_exit(client_proc);
692 		break;
693 	case MSG_SHUTDOWN:
694 		if (datalen != 0)
695 			fatalx("bad MSG_SHUTDOWN size");
696 
697 		proc_send(client_peer, MSG_EXITING, -1, NULL, 0);
698 		client_exitreason = CLIENT_EXIT_SERVER_EXITED;
699 		client_exitval = 1;
700 		break;
701 	case MSG_SUSPEND:
702 		if (datalen != 0)
703 			fatalx("bad MSG_SUSPEND size");
704 
705 		memset(&sigact, 0, sizeof sigact);
706 		sigemptyset(&sigact.sa_mask);
707 		sigact.sa_flags = SA_RESTART;
708 		sigact.sa_handler = SIG_DFL;
709 		if (sigaction(SIGTSTP, &sigact, NULL) != 0)
710 			fatal("sigaction failed");
711 		kill(getpid(), SIGTSTP);
712 		break;
713 	case MSG_LOCK:
714 		if (datalen == 0 || data[datalen - 1] != '\0')
715 			fatalx("bad MSG_LOCK string");
716 
717 		system(data);
718 		proc_send(client_peer, MSG_UNLOCK, -1, NULL, 0);
719 		break;
720 	}
721 }
722