xref: /netbsd-src/external/bsd/tmux/dist/client.c (revision 890b6d91a44b7fcb2dfbcbc1e93463086e462d2d)
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/socket.h>
21 #include <sys/uio.h>
22 #include <sys/un.h>
23 #include <sys/wait.h>
24 #include <sys/file.h>
25 
26 #include <errno.h>
27 #include <fcntl.h>
28 #include <signal.h>
29 #include <stdlib.h>
30 #include <string.h>
31 #include <unistd.h>
32 
33 #include "tmux.h"
34 
35 static struct tmuxproc	*client_proc;
36 static struct tmuxpeer	*client_peer;
37 static uint64_t		 client_flags;
38 static int		 client_suspended;
39 static enum {
40 	CLIENT_EXIT_NONE,
41 	CLIENT_EXIT_DETACHED,
42 	CLIENT_EXIT_DETACHED_HUP,
43 	CLIENT_EXIT_LOST_TTY,
44 	CLIENT_EXIT_TERMINATED,
45 	CLIENT_EXIT_LOST_SERVER,
46 	CLIENT_EXIT_EXITED,
47 	CLIENT_EXIT_SERVER_EXITED,
48 	CLIENT_EXIT_MESSAGE_PROVIDED
49 } client_exitreason = CLIENT_EXIT_NONE;
50 static int		 client_exitflag;
51 static int		 client_exitval;
52 static enum msgtype	 client_exittype;
53 static const char	*client_exitsession;
54 static char		*client_exitmessage;
55 static const char	*client_execshell;
56 static const char	*client_execcmd;
57 static int		 client_attached;
58 static struct client_files client_files = RB_INITIALIZER(&client_files);
59 
60 static __dead void	 client_exec(const char *,const char *);
61 static int		 client_get_lock(char *);
62 static int		 client_connect(struct event_base *, const char *,
63 			     uint64_t);
64 static void		 client_send_identify(const char *, const char *,
65 			     char **, u_int, const char *, int);
66 static void		 client_signal(int);
67 static void		 client_dispatch(struct imsg *, void *);
68 static void		 client_dispatch_attached(struct imsg *);
69 static void		 client_dispatch_wait(struct imsg *);
70 static const char	*client_exit_message(void);
71 
72 /*
73  * Get server create lock. If already held then server start is happening in
74  * another client, so block until the lock is released and return -2 to
75  * retry. Return -1 on failure to continue and start the server anyway.
76  */
77 static int
78 client_get_lock(char *lockfile)
79 {
80 	int lockfd;
81 
82 	log_debug("lock file is %s", lockfile);
83 
84 	if ((lockfd = open(lockfile, O_WRONLY|O_CREAT, 0600)) == -1) {
85 		log_debug("open failed: %s", strerror(errno));
86 		return (-1);
87 	}
88 
89 	if (flock(lockfd, LOCK_EX|LOCK_NB) == -1) {
90 		log_debug("flock failed: %s", strerror(errno));
91 		if (errno != EAGAIN)
92 			return (lockfd);
93 		while (flock(lockfd, LOCK_EX) == -1 && errno == EINTR)
94 			/* nothing */;
95 		close(lockfd);
96 		return (-2);
97 	}
98 	log_debug("flock succeeded");
99 
100 	return (lockfd);
101 }
102 
103 /* Connect client to server. */
104 static int
105 client_connect(struct event_base *base, const char *path, uint64_t flags)
106 {
107 	struct sockaddr_un	sa;
108 	size_t			size;
109 	int			fd, lockfd = -1, locked = 0;
110 	char		       *lockfile = NULL;
111 
112 	memset(&sa, 0, sizeof sa);
113 	sa.sun_family = AF_UNIX;
114 	size = strlcpy(sa.sun_path, path, sizeof sa.sun_path);
115 	if (size >= sizeof sa.sun_path) {
116 		errno = ENAMETOOLONG;
117 		return (-1);
118 	}
119 	log_debug("socket is %s", path);
120 
121 retry:
122 	if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1)
123 		return (-1);
124 
125 	log_debug("trying connect");
126 	if (connect(fd, (struct sockaddr *)&sa, sizeof sa) == -1) {
127 		log_debug("connect failed: %s", strerror(errno));
128 		if (errno != ECONNREFUSED && errno != ENOENT)
129 			goto failed;
130 		if (flags & CLIENT_NOSTARTSERVER)
131 			goto failed;
132 		if (~flags & CLIENT_STARTSERVER)
133 			goto failed;
134 		close(fd);
135 
136 		if (!locked) {
137 			xasprintf(&lockfile, "%s.lock", path);
138 			if ((lockfd = client_get_lock(lockfile)) < 0) {
139 				log_debug("didn't get lock (%d)", lockfd);
140 
141 				free(lockfile);
142 				lockfile = NULL;
143 
144 				if (lockfd == -2)
145 					goto retry;
146 			}
147 			log_debug("got lock (%d)", lockfd);
148 
149 			/*
150 			 * Always retry at least once, even if we got the lock,
151 			 * because another client could have taken the lock,
152 			 * started the server and released the lock between our
153 			 * connect() and flock().
154 			 */
155 			locked = 1;
156 			goto retry;
157 		}
158 
159 		if (lockfd >= 0 && unlink(path) != 0 && errno != ENOENT) {
160 			free(lockfile);
161 			close(lockfd);
162 			return (-1);
163 		}
164 		fd = server_start(client_proc, flags, base, lockfd, lockfile);
165 	}
166 
167 	if (locked && lockfd >= 0) {
168 		free(lockfile);
169 		close(lockfd);
170 	}
171 	setblocking(fd, 0);
172 	return (fd);
173 
174 failed:
175 	if (locked) {
176 		free(lockfile);
177 		close(lockfd);
178 	}
179 	close(fd);
180 	return (-1);
181 }
182 
183 /* Get exit string from reason number. */
184 const char *
185 client_exit_message(void)
186 {
187 	static char msg[256];
188 
189 	switch (client_exitreason) {
190 	case CLIENT_EXIT_NONE:
191 		break;
192 	case CLIENT_EXIT_DETACHED:
193 		if (client_exitsession != NULL) {
194 			xsnprintf(msg, sizeof msg, "detached "
195 			    "(from session %s)", client_exitsession);
196 			return (msg);
197 		}
198 		return ("detached");
199 	case CLIENT_EXIT_DETACHED_HUP:
200 		if (client_exitsession != NULL) {
201 			xsnprintf(msg, sizeof msg, "detached and SIGHUP "
202 			    "(from session %s)", client_exitsession);
203 			return (msg);
204 		}
205 		return ("detached and SIGHUP");
206 	case CLIENT_EXIT_LOST_TTY:
207 		return ("lost tty");
208 	case CLIENT_EXIT_TERMINATED:
209 		return ("terminated");
210 	case CLIENT_EXIT_LOST_SERVER:
211 		return ("server exited unexpectedly");
212 	case CLIENT_EXIT_EXITED:
213 		return ("exited");
214 	case CLIENT_EXIT_SERVER_EXITED:
215 		return ("server exited");
216 	case CLIENT_EXIT_MESSAGE_PROVIDED:
217 		return (client_exitmessage);
218 	}
219 	return ("unknown reason");
220 }
221 
222 /* Exit if all streams flushed. */
223 static void
224 client_exit(void)
225 {
226 	if (!file_write_left(&client_files))
227 		proc_exit(client_proc);
228 }
229 
230 /* Client main loop. */
231 int
232 client_main(struct event_base *base, int argc, char **argv, uint64_t flags,
233     int feat)
234 {
235 	struct cmd_parse_result	*pr;
236 	struct msg_command	*data;
237 	int			 fd, i;
238 	const char		*ttynam, *termname, *cwd;
239 	pid_t			 ppid;
240 	enum msgtype		 msg;
241 	struct termios		 tio, saved_tio;
242 	size_t			 size, linesize = 0;
243 	ssize_t			 linelen;
244 	char			*line = NULL, **caps = NULL, *cause;
245 	u_int			 ncaps = 0;
246 	struct args_value	*values;
247 
248 	/* Set up the initial command. */
249 	if (shell_command != NULL) {
250 		msg = MSG_SHELL;
251 		flags |= CLIENT_STARTSERVER;
252 	} else if (argc == 0) {
253 		msg = MSG_COMMAND;
254 		flags |= CLIENT_STARTSERVER;
255 	} else {
256 		msg = MSG_COMMAND;
257 
258 		/*
259 		 * It's annoying parsing the command string twice (in client
260 		 * and later in server) but it is necessary to get the start
261 		 * server flag.
262 		 */
263 		values = args_from_vector(argc, argv);
264 		pr = cmd_parse_from_arguments(values, argc, NULL);
265 		if (pr->status == CMD_PARSE_SUCCESS) {
266 			if (cmd_list_any_have(pr->cmdlist, CMD_STARTSERVER))
267 				flags |= CLIENT_STARTSERVER;
268 			cmd_list_free(pr->cmdlist);
269 		} else
270 			free(pr->error);
271 		args_free_values(values, argc);
272 		free(values);
273 	}
274 
275 	/* Create client process structure (starts logging). */
276 	client_proc = proc_start("client");
277 	proc_set_signals(client_proc, client_signal);
278 
279 	/* Save the flags. */
280 	client_flags = flags;
281 	log_debug("flags are %#llx", (unsigned long long)client_flags);
282 
283 	/* Initialize the client socket and start the server. */
284 #ifdef HAVE_SYSTEMD
285 	if (systemd_activated()) {
286 		/* socket-based activation, do not even try to be a client. */
287 		fd = server_start(client_proc, flags, base, 0, NULL);
288 	} else
289 #endif
290 	fd = client_connect(base, socket_path, client_flags);
291 	if (fd == -1) {
292 		if (errno == ECONNREFUSED) {
293 			fprintf(stderr, "no server running on %s\n",
294 			    socket_path);
295 		} else {
296 			fprintf(stderr, "error connecting to %s (%s)\n",
297 			    socket_path, strerror(errno));
298 		}
299 		return (1);
300 	}
301 	client_peer = proc_add_peer(client_proc, fd, client_dispatch, NULL);
302 
303 	/* Save these before pledge(). */
304 	if ((cwd = find_cwd()) == NULL && (cwd = find_home()) == NULL)
305 		cwd = "/";
306 	if ((ttynam = ttyname(STDIN_FILENO)) == NULL)
307 		ttynam = "";
308 	if ((termname = getenv("TERM")) == NULL)
309 		termname = "";
310 
311 	/*
312 	 * Drop privileges for client. "proc exec" is needed for -c and for
313 	 * locking (which uses system(3)).
314 	 *
315 	 * "tty" is needed to restore termios(4) and also for some reason -CC
316 	 * does not work properly without it (input is not recognised).
317 	 *
318 	 * "sendfd" is dropped later in client_dispatch_wait().
319 	 */
320 	if (pledge(
321 	    "stdio rpath wpath cpath unix sendfd proc exec tty",
322 	    NULL) != 0)
323 		fatal("pledge failed");
324 
325 	/* Load terminfo entry if any. */
326 	if (isatty(STDIN_FILENO) &&
327 	    *termname != '\0' &&
328 	    tty_term_read_list(termname, STDIN_FILENO, &caps, &ncaps,
329 	    &cause) != 0) {
330 		fprintf(stderr, "%s\n", cause);
331 		free(cause);
332 		return (1);
333 	}
334 
335 	/* Free stuff that is not used in the client. */
336 	if (ptm_fd != -1)
337 		close(ptm_fd);
338 	options_free(global_options);
339 	options_free(global_s_options);
340 	options_free(global_w_options);
341 	environ_free(global_environ);
342 
343 	/* Set up control mode. */
344 	if (client_flags & CLIENT_CONTROLCONTROL) {
345 		if (tcgetattr(STDIN_FILENO, &saved_tio) != 0) {
346 			fprintf(stderr, "tcgetattr failed: %s\n",
347 			    strerror(errno));
348 			return (1);
349 		}
350 		cfmakeraw(&tio);
351 		tio.c_iflag = ICRNL|IXANY;
352 		tio.c_oflag = OPOST|ONLCR;
353 #ifdef NOKERNINFO
354 		tio.c_lflag = NOKERNINFO;
355 #endif
356 		tio.c_cflag = CREAD|CS8|HUPCL;
357 		tio.c_cc[VMIN] = 1;
358 		tio.c_cc[VTIME] = 0;
359 		cfsetispeed(&tio, cfgetispeed(&saved_tio));
360 		cfsetospeed(&tio, cfgetospeed(&saved_tio));
361 		tcsetattr(STDIN_FILENO, TCSANOW, &tio);
362 	}
363 
364 	/* Send identify messages. */
365 	client_send_identify(ttynam, termname, caps, ncaps, cwd, feat);
366 	tty_term_free_list(caps, ncaps);
367 	proc_flush_peer(client_peer);
368 
369 	/* Send first command. */
370 	if (msg == MSG_COMMAND) {
371 		/* How big is the command? */
372 		size = 0;
373 		for (i = 0; i < argc; i++)
374 			size += strlen(argv[i]) + 1;
375 		if (size > MAX_IMSGSIZE - (sizeof *data)) {
376 			fprintf(stderr, "command too long\n");
377 			return (1);
378 		}
379 		data = xmalloc((sizeof *data) + size);
380 
381 		/* Prepare command for server. */
382 		data->argc = argc;
383 		if (cmd_pack_argv(argc, argv, (char *)(data + 1), size) != 0) {
384 			fprintf(stderr, "command too long\n");
385 			free(data);
386 			return (1);
387 		}
388 		size += sizeof *data;
389 
390 		/* Send the command. */
391 		if (proc_send(client_peer, msg, -1, data, size) != 0) {
392 			fprintf(stderr, "failed to send command\n");
393 			free(data);
394 			return (1);
395 		}
396 		free(data);
397 	} else if (msg == MSG_SHELL)
398 		proc_send(client_peer, msg, -1, NULL, 0);
399 
400 	/* Start main loop. */
401 	proc_loop(client_proc, NULL);
402 
403 	/* Run command if user requested exec, instead of exiting. */
404 	if (client_exittype == MSG_EXEC) {
405 		if (client_flags & CLIENT_CONTROLCONTROL)
406 			tcsetattr(STDOUT_FILENO, TCSAFLUSH, &saved_tio);
407 		client_exec(client_execshell, client_execcmd);
408 	}
409 
410 	/* Restore streams to blocking. */
411 	setblocking(STDIN_FILENO, 1);
412 	setblocking(STDOUT_FILENO, 1);
413 	setblocking(STDERR_FILENO, 1);
414 
415 	/* Print the exit message, if any, and exit. */
416 	if (client_attached) {
417 		if (client_exitreason != CLIENT_EXIT_NONE)
418 			printf("[%s]\n", client_exit_message());
419 
420 		ppid = getppid();
421 		if (client_exittype == MSG_DETACHKILL && ppid > 1)
422 			kill(ppid, SIGHUP);
423 	} else if (client_flags & CLIENT_CONTROL) {
424 		if (client_exitreason != CLIENT_EXIT_NONE)
425 			printf("%%exit %s\n", client_exit_message());
426 		else
427 			printf("%%exit\n");
428 		fflush(stdout);
429 		if (client_flags & CLIENT_CONTROL_WAITEXIT) {
430 			setvbuf(stdin, NULL, _IOLBF, 0);
431 			for (;;) {
432 				linelen = getline(&line, &linesize, stdin);
433 				if (linelen <= 1)
434 					break;
435 			}
436 			free(line);
437 		}
438 		if (client_flags & CLIENT_CONTROLCONTROL) {
439 			printf("\033\\");
440 			fflush(stdout);
441 			tcsetattr(STDOUT_FILENO, TCSAFLUSH, &saved_tio);
442 		}
443 	} else if (client_exitreason != CLIENT_EXIT_NONE)
444 		fprintf(stderr, "%s\n", client_exit_message());
445 	return (client_exitval);
446 }
447 
448 /* Send identify messages to server. */
449 static void
450 client_send_identify(const char *ttynam, const char *termname, char **caps,
451     u_int ncaps, const char *cwd, int feat)
452 {
453 	char	**ss;
454 	size_t	  sslen;
455 	int	  fd;
456 	uint64_t  flags = client_flags;
457 	pid_t	  pid;
458 	u_int	  i;
459 
460 	proc_send(client_peer, MSG_IDENTIFY_LONGFLAGS, -1, &flags, sizeof flags);
461 	proc_send(client_peer, MSG_IDENTIFY_LONGFLAGS, -1, &client_flags,
462 	    sizeof client_flags);
463 
464 	proc_send(client_peer, MSG_IDENTIFY_TERM, -1, termname,
465 	    strlen(termname) + 1);
466 	proc_send(client_peer, MSG_IDENTIFY_FEATURES, -1, &feat, sizeof feat);
467 
468 	proc_send(client_peer, MSG_IDENTIFY_TTYNAME, -1, ttynam,
469 	    strlen(ttynam) + 1);
470 	proc_send(client_peer, MSG_IDENTIFY_CWD, -1, cwd, strlen(cwd) + 1);
471 
472 	for (i = 0; i < ncaps; i++) {
473 		proc_send(client_peer, MSG_IDENTIFY_TERMINFO, -1,
474 		    caps[i], strlen(caps[i]) + 1);
475 	}
476 
477 	if ((fd = dup(STDIN_FILENO)) == -1)
478 		fatal("dup failed");
479 	proc_send(client_peer, MSG_IDENTIFY_STDIN, fd, NULL, 0);
480 	if ((fd = dup(STDOUT_FILENO)) == -1)
481 		fatal("dup failed");
482 	proc_send(client_peer, MSG_IDENTIFY_STDOUT, fd, NULL, 0);
483 
484 	pid = getpid();
485 	proc_send(client_peer, MSG_IDENTIFY_CLIENTPID, -1, &pid, sizeof pid);
486 
487 	for (ss = environ; *ss != NULL; ss++) {
488 		sslen = strlen(*ss) + 1;
489 		if (sslen > MAX_IMSGSIZE - IMSG_HEADER_SIZE)
490 			continue;
491 		proc_send(client_peer, MSG_IDENTIFY_ENVIRON, -1, *ss, sslen);
492 	}
493 
494 	proc_send(client_peer, MSG_IDENTIFY_DONE, -1, NULL, 0);
495 }
496 
497 /* Run command in shell; used for -c. */
498 static __dead void
499 client_exec(const char *shell, const char *shellcmd)
500 {
501 	char	*argv0;
502 
503 	log_debug("shell %s, command %s", shell, shellcmd);
504 	argv0 = shell_argv0(shell, !!(client_flags & CLIENT_LOGIN));
505 	setenv("SHELL", shell, 1);
506 
507 	proc_clear_signals(client_proc, 1);
508 
509 	setblocking(STDIN_FILENO, 1);
510 	setblocking(STDOUT_FILENO, 1);
511 	setblocking(STDERR_FILENO, 1);
512 	closefrom(STDERR_FILENO + 1);
513 
514 	execl(shell, argv0, "-c", shellcmd, (char *) NULL);
515 	fatal("execl failed");
516 }
517 
518 /* Callback to handle signals in the client. */
519 static void
520 client_signal(int sig)
521 {
522 	struct sigaction sigact;
523 	int		 status;
524 	pid_t		 pid;
525 
526 	log_debug("%s: %s", __func__, strsignal(sig));
527 	if (sig == SIGCHLD) {
528 		for (;;) {
529 			pid = waitpid(WAIT_ANY, &status, WNOHANG);
530 			if (pid == 0)
531 				break;
532 			if (pid == -1) {
533 				if (errno == ECHILD)
534 					break;
535 				log_debug("waitpid failed: %s",
536 				    strerror(errno));
537 			}
538 		}
539 	} else if (!client_attached) {
540 		if (sig == SIGTERM || sig == SIGHUP)
541 			proc_exit(client_proc);
542 	} else {
543 		switch (sig) {
544 		case SIGHUP:
545 			client_exitreason = CLIENT_EXIT_LOST_TTY;
546 			client_exitval = 1;
547 			proc_send(client_peer, MSG_EXITING, -1, NULL, 0);
548 			break;
549 		case SIGTERM:
550 			if (!client_suspended)
551 				client_exitreason = CLIENT_EXIT_TERMINATED;
552 			client_exitval = 1;
553 			proc_send(client_peer, MSG_EXITING, -1, NULL, 0);
554 			break;
555 		case SIGWINCH:
556 			proc_send(client_peer, MSG_RESIZE, -1, NULL, 0);
557 			break;
558 		case SIGCONT:
559 			memset(&sigact, 0, sizeof sigact);
560 			sigemptyset(&sigact.sa_mask);
561 			sigact.sa_flags = SA_RESTART;
562 			sigact.sa_handler = SIG_IGN;
563 			if (sigaction(SIGTSTP, &sigact, NULL) != 0)
564 				fatal("sigaction failed");
565 			proc_send(client_peer, MSG_WAKEUP, -1, NULL, 0);
566 			client_suspended = 0;
567 			break;
568 		}
569 	}
570 }
571 
572 /* Callback for file write error or close. */
573 static void
574 client_file_check_cb(__unused struct client *c, __unused const char *path,
575     __unused int error, __unused int closed, __unused struct evbuffer *buffer,
576     __unused void *data)
577 {
578 	if (client_exitflag)
579 		client_exit();
580 }
581 
582 /* Callback for client read events. */
583 static void
584 client_dispatch(struct imsg *imsg, __unused void *arg)
585 {
586 	if (imsg == NULL) {
587 		if (!client_exitflag) {
588 			client_exitreason = CLIENT_EXIT_LOST_SERVER;
589 			client_exitval = 1;
590 		}
591 		proc_exit(client_proc);
592 		return;
593 	}
594 
595 	if (client_attached)
596 		client_dispatch_attached(imsg);
597 	else
598 		client_dispatch_wait(imsg);
599 }
600 
601 /* Process an exit message. */
602 static void
603 client_dispatch_exit_message(char *data, size_t datalen)
604 {
605 	int	retval;
606 
607 	if (datalen < sizeof retval && datalen != 0)
608 		fatalx("bad MSG_EXIT size");
609 
610 	if (datalen >= sizeof retval) {
611 		memcpy(&retval, data, sizeof retval);
612 		client_exitval = retval;
613 	}
614 
615 	if (datalen > sizeof retval) {
616 		datalen -= sizeof retval;
617 		data += sizeof retval;
618 
619 		client_exitmessage = xmalloc(datalen);
620 		memcpy(client_exitmessage, data, datalen);
621 		client_exitmessage[datalen - 1] = '\0';
622 
623 		client_exitreason = CLIENT_EXIT_MESSAGE_PROVIDED;
624 	}
625 }
626 
627 /* Dispatch imsgs when in wait state (before MSG_READY). */
628 static void
629 client_dispatch_wait(struct imsg *imsg)
630 {
631 	char		*data;
632 	ssize_t		 datalen;
633 	static int	 pledge_applied;
634 
635 	/*
636 	 * "sendfd" is no longer required once all of the identify messages
637 	 * have been sent. We know the server won't send us anything until that
638 	 * point (because we don't ask it to), so we can drop "sendfd" once we
639 	 * get the first message from the server.
640 	 */
641 	if (!pledge_applied) {
642 		if (pledge(
643 		    "stdio rpath wpath cpath unix proc exec tty",
644 		    NULL) != 0)
645 			fatal("pledge failed");
646 		pledge_applied = 1;
647 	}
648 
649 	data = imsg->data;
650 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
651 
652 	switch (imsg->hdr.type) {
653 	case MSG_EXIT:
654 	case MSG_SHUTDOWN:
655 		client_dispatch_exit_message(data, datalen);
656 		client_exitflag = 1;
657 		client_exit();
658 		break;
659 	case MSG_READY:
660 		if (datalen != 0)
661 			fatalx("bad MSG_READY size");
662 
663 		client_attached = 1;
664 		proc_send(client_peer, MSG_RESIZE, -1, NULL, 0);
665 		break;
666 	case MSG_VERSION:
667 		if (datalen != 0)
668 			fatalx("bad MSG_VERSION size");
669 
670 		fprintf(stderr, "protocol version mismatch "
671 		    "(client %d, server %u)\n", PROTOCOL_VERSION,
672 		    imsg->hdr.peerid & 0xff);
673 		client_exitval = 1;
674 		proc_exit(client_proc);
675 		break;
676 	case MSG_FLAGS:
677 		if (datalen != sizeof client_flags)
678 			fatalx("bad MSG_FLAGS string");
679 
680 		memcpy(&client_flags, data, sizeof client_flags);
681 		log_debug("new flags are %#llx",
682 		    (unsigned long long)client_flags);
683 		break;
684 	case MSG_SHELL:
685 		if (datalen == 0 || data[datalen - 1] != '\0')
686 			fatalx("bad MSG_SHELL string");
687 
688 		client_exec(data, shell_command);
689 		/* NOTREACHED */
690 	case MSG_DETACH:
691 	case MSG_DETACHKILL:
692 		proc_send(client_peer, MSG_EXITING, -1, NULL, 0);
693 		break;
694 	case MSG_EXITED:
695 		proc_exit(client_proc);
696 		break;
697 	case MSG_READ_OPEN:
698 		file_read_open(&client_files, client_peer, imsg, 1,
699 		    !(client_flags & CLIENT_CONTROL), client_file_check_cb,
700 		    NULL);
701 		break;
702 	case MSG_READ_CANCEL:
703 		file_read_cancel(&client_files, imsg);
704 		break;
705 	case MSG_WRITE_OPEN:
706 		file_write_open(&client_files, client_peer, imsg, 1,
707 		    !(client_flags & CLIENT_CONTROL), client_file_check_cb,
708 		    NULL);
709 		break;
710 	case MSG_WRITE:
711 		file_write_data(&client_files, imsg);
712 		break;
713 	case MSG_WRITE_CLOSE:
714 		file_write_close(&client_files, imsg);
715 		break;
716 	case MSG_OLDSTDERR:
717 	case MSG_OLDSTDIN:
718 	case MSG_OLDSTDOUT:
719 		fprintf(stderr, "server version is too old for client\n");
720 		proc_exit(client_proc);
721 		break;
722 	}
723 }
724 
725 /* Dispatch imsgs in attached state (after MSG_READY). */
726 static void
727 client_dispatch_attached(struct imsg *imsg)
728 {
729 	struct sigaction	 sigact;
730 	char			*data;
731 	ssize_t			 datalen;
732 
733 	data = imsg->data;
734 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
735 
736 	switch (imsg->hdr.type) {
737 	case MSG_FLAGS:
738 		if (datalen != sizeof client_flags)
739 			fatalx("bad MSG_FLAGS string");
740 
741 		memcpy(&client_flags, data, sizeof client_flags);
742 		log_debug("new flags are %#llx",
743 		    (unsigned long long)client_flags);
744 		break;
745 	case MSG_DETACH:
746 	case MSG_DETACHKILL:
747 		if (datalen == 0 || data[datalen - 1] != '\0')
748 			fatalx("bad MSG_DETACH string");
749 
750 		client_exitsession = xstrdup(data);
751 		client_exittype = imsg->hdr.type;
752 		if (imsg->hdr.type == MSG_DETACHKILL)
753 			client_exitreason = CLIENT_EXIT_DETACHED_HUP;
754 		else
755 			client_exitreason = CLIENT_EXIT_DETACHED;
756 		proc_send(client_peer, MSG_EXITING, -1, NULL, 0);
757 		break;
758 	case MSG_EXEC:
759 		if (datalen == 0 || data[datalen - 1] != '\0' ||
760 		    strlen(data) + 1 == (size_t)datalen)
761 			fatalx("bad MSG_EXEC string");
762 		client_execcmd = xstrdup(data);
763 		client_execshell = xstrdup(data + strlen(data) + 1);
764 
765 		client_exittype = imsg->hdr.type;
766 		proc_send(client_peer, MSG_EXITING, -1, NULL, 0);
767 		break;
768 	case MSG_EXIT:
769 		client_dispatch_exit_message(data, datalen);
770 		if (client_exitreason == CLIENT_EXIT_NONE)
771 			client_exitreason = CLIENT_EXIT_EXITED;
772 		proc_send(client_peer, MSG_EXITING, -1, NULL, 0);
773 		break;
774 	case MSG_EXITED:
775 		if (datalen != 0)
776 			fatalx("bad MSG_EXITED size");
777 
778 		proc_exit(client_proc);
779 		break;
780 	case MSG_SHUTDOWN:
781 		if (datalen != 0)
782 			fatalx("bad MSG_SHUTDOWN size");
783 
784 		proc_send(client_peer, MSG_EXITING, -1, NULL, 0);
785 		client_exitreason = CLIENT_EXIT_SERVER_EXITED;
786 		client_exitval = 1;
787 		break;
788 	case MSG_SUSPEND:
789 		if (datalen != 0)
790 			fatalx("bad MSG_SUSPEND size");
791 
792 		memset(&sigact, 0, sizeof sigact);
793 		sigemptyset(&sigact.sa_mask);
794 		sigact.sa_flags = SA_RESTART;
795 		sigact.sa_handler = SIG_DFL;
796 		if (sigaction(SIGTSTP, &sigact, NULL) != 0)
797 			fatal("sigaction failed");
798 		client_suspended = 1;
799 		kill(getpid(), SIGTSTP);
800 		break;
801 	case MSG_LOCK:
802 		if (datalen == 0 || data[datalen - 1] != '\0')
803 			fatalx("bad MSG_LOCK string");
804 
805 		system(data);
806 		proc_send(client_peer, MSG_UNLOCK, -1, NULL, 0);
807 		break;
808 	}
809 }
810