xref: /openbsd-src/usr.bin/tmux/server-client.c (revision 50027fe110c3c362514cbbf1128910104a00203e)
1 /* $OpenBSD: server-client.c,v 1.26 2009/12/10 09:16:52 nicm Exp $ */
2 
3 /*
4  * Copyright (c) 2009 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 
21 #include <event.h>
22 #include <fcntl.h>
23 #include <string.h>
24 #include <time.h>
25 #include <paths.h>
26 #include <unistd.h>
27 
28 #include "tmux.h"
29 
30 void	server_client_handle_key(int, struct mouse_event *, void *);
31 void	server_client_repeat_timer(int, short, void *);
32 void	server_client_check_redraw(struct client *);
33 void	server_client_set_title(struct client *);
34 void	server_client_reset_state(struct client *);
35 
36 int	server_client_msg_dispatch(struct client *);
37 void	server_client_msg_command(struct client *, struct msg_command_data *);
38 void	server_client_msg_identify(
39 	    struct client *, struct msg_identify_data *, int);
40 void	server_client_msg_shell(struct client *);
41 
42 void printflike2 server_client_msg_error(struct cmd_ctx *, const char *, ...);
43 void printflike2 server_client_msg_print(struct cmd_ctx *, const char *, ...);
44 void printflike2 server_client_msg_info(struct cmd_ctx *, const char *, ...);
45 
46 /* Create a new client. */
47 void
48 server_client_create(int fd)
49 {
50 	struct client	*c;
51 	int		 mode;
52 	u_int		 i;
53 
54 	if ((mode = fcntl(fd, F_GETFL)) == -1)
55 		fatal("fcntl failed");
56 	if (fcntl(fd, F_SETFL, mode|O_NONBLOCK) == -1)
57 		fatal("fcntl failed");
58 	if (fcntl(fd, F_SETFD, FD_CLOEXEC) == -1)
59 		fatal("fcntl failed");
60 
61 	c = xcalloc(1, sizeof *c);
62 	c->references = 0;
63 	imsg_init(&c->ibuf, fd);
64 	server_update_event(c);
65 
66 	if (gettimeofday(&c->creation_time, NULL) != 0)
67 		fatal("gettimeofday failed");
68 	memcpy(&c->activity_time, &c->creation_time, sizeof c->activity_time);
69 
70 	ARRAY_INIT(&c->prompt_hdata);
71 
72 	c->tty.fd = -1;
73 	c->title = NULL;
74 
75 	c->session = NULL;
76 	c->tty.sx = 80;
77 	c->tty.sy = 24;
78 
79 	screen_init(&c->status, c->tty.sx, 1, 0);
80 	job_tree_init(&c->status_jobs);
81 
82 	c->message_string = NULL;
83 	ARRAY_INIT(&c->message_log);
84 
85 	c->prompt_string = NULL;
86 	c->prompt_buffer = NULL;
87 	c->prompt_index = 0;
88 
89 	evtimer_set(&c->repeat_timer, server_client_repeat_timer, c);
90 
91 	for (i = 0; i < ARRAY_LENGTH(&clients); i++) {
92 		if (ARRAY_ITEM(&clients, i) == NULL) {
93 			ARRAY_SET(&clients, i, c);
94 			return;
95 		}
96 	}
97 	ARRAY_ADD(&clients, c);
98 	log_debug("new client %d", fd);
99 }
100 
101 /* Lost a client. */
102 void
103 server_client_lost(struct client *c)
104 {
105 	struct message_entry	*msg;
106 	u_int			 i;
107 
108 	for (i = 0; i < ARRAY_LENGTH(&clients); i++) {
109 		if (ARRAY_ITEM(&clients, i) == c)
110 			ARRAY_SET(&clients, i, NULL);
111 	}
112 	log_debug("lost client %d", c->ibuf.fd);
113 
114 	/*
115 	 * If CLIENT_TERMINAL hasn't been set, then tty_init hasn't been called
116 	 * and tty_free might close an unrelated fd.
117 	 */
118 	if (c->flags & CLIENT_TERMINAL)
119 		tty_free(&c->tty);
120 
121 	screen_free(&c->status);
122 	job_tree_free(&c->status_jobs);
123 
124 	if (c->title != NULL)
125 		xfree(c->title);
126 
127 	evtimer_del(&c->repeat_timer);
128 
129 	evtimer_del(&c->identify_timer);
130 
131 	if (c->message_string != NULL)
132 		xfree(c->message_string);
133 	evtimer_del(&c->message_timer);
134 	for (i = 0; i < ARRAY_LENGTH(&c->message_log); i++) {
135 		msg = &ARRAY_ITEM(&c->message_log, i);
136 		xfree(msg->msg);
137 	}
138 	ARRAY_FREE(&c->message_log);
139 
140 	if (c->prompt_string != NULL)
141 		xfree(c->prompt_string);
142 	if (c->prompt_buffer != NULL)
143 		xfree(c->prompt_buffer);
144 	for (i = 0; i < ARRAY_LENGTH(&c->prompt_hdata); i++)
145 		xfree(ARRAY_ITEM(&c->prompt_hdata, i));
146 	ARRAY_FREE(&c->prompt_hdata);
147 
148 	if (c->cwd != NULL)
149 		xfree(c->cwd);
150 
151 	close(c->ibuf.fd);
152 	imsg_clear(&c->ibuf);
153 	event_del(&c->event);
154 
155 	for (i = 0; i < ARRAY_LENGTH(&dead_clients); i++) {
156 		if (ARRAY_ITEM(&dead_clients, i) == NULL) {
157 			ARRAY_SET(&dead_clients, i, c);
158 			break;
159 		}
160 	}
161 	if (i == ARRAY_LENGTH(&dead_clients))
162 		ARRAY_ADD(&dead_clients, c);
163 	c->flags |= CLIENT_DEAD;
164 
165 	recalculate_sizes();
166 	server_update_socket();
167 }
168 
169 /* Process a single client event. */
170 void
171 server_client_callback(int fd, short events, void *data)
172 {
173 	struct client	*c = data;
174 
175 	if (c->flags & CLIENT_DEAD)
176 		return;
177 
178 	if (fd == c->ibuf.fd) {
179 		if (events & EV_WRITE && msgbuf_write(&c->ibuf.w) < 0)
180 			goto client_lost;
181 
182 		if (c->flags & CLIENT_BAD) {
183 			if (c->ibuf.w.queued == 0)
184 				goto client_lost;
185 			return;
186 		}
187 
188 		if (events & EV_READ && server_client_msg_dispatch(c) != 0)
189 			goto client_lost;
190 	}
191 
192 	server_update_event(c);
193 	return;
194 
195 client_lost:
196 	server_client_lost(c);
197 }
198 
199 /* Handle client status timer. */
200 void
201 server_client_status_timer(void)
202 {
203 	struct client	*c;
204 	struct session	*s;
205 	struct job	*job;
206 	struct timeval	 tv;
207 	u_int		 i;
208 	int		 interval;
209 	time_t		 difference;
210 
211 	if (gettimeofday(&tv, NULL) != 0)
212 		fatal("gettimeofday failed");
213 
214 	for (i = 0; i < ARRAY_LENGTH(&clients); i++) {
215 		c = ARRAY_ITEM(&clients, i);
216 		if (c == NULL || c->session == NULL)
217 			continue;
218 		if (c->message_string != NULL || c->prompt_string != NULL) {
219 			/*
220 			 * Don't need timed redraw for messages/prompts so bail
221 			 * now. The status timer isn't reset when they are
222 			 * redrawn anyway.
223 			 */
224 			continue;
225 		}
226 		s = c->session;
227 
228 		if (!options_get_number(&s->options, "status"))
229 			continue;
230 		interval = options_get_number(&s->options, "status-interval");
231 
232 		difference = tv.tv_sec - c->status_timer.tv_sec;
233 		if (difference >= interval) {
234 			RB_FOREACH(job, jobs, &c->status_jobs)
235 				job_run(job);
236 			c->flags |= CLIENT_STATUS;
237 		}
238 	}
239 }
240 
241 /* Handle data key input from client. */
242 void
243 server_client_handle_key(int key, struct mouse_event *mouse, void *data)
244 {
245 	struct client		*c = data;
246 	struct session		*s;
247 	struct window		*w;
248 	struct window_pane	*wp;
249 	struct options		*oo;
250 	struct timeval		 tv;
251 	struct key_binding	*bd;
252 	struct keylist		*keylist;
253 	int		      	 xtimeout, isprefix;
254 	u_int			 i;
255 
256 	/* Check the client is good to accept input. */
257 	if ((c->flags & (CLIENT_DEAD|CLIENT_SUSPENDED)) != 0)
258 		return;
259 	if (c->session == NULL)
260 		return;
261 	s = c->session;
262 
263 	/* Update the activity timer. */
264 	if (gettimeofday(&c->activity_time, NULL) != 0)
265 		fatal("gettimeofday failed");
266 	memcpy(&s->activity_time, &c->activity_time, sizeof s->activity_time);
267 
268 	w = c->session->curw->window;
269 	wp = w->active;
270 	oo = &c->session->options;
271 
272 	/* Special case: number keys jump to pane in identify mode. */
273 	if (c->flags & CLIENT_IDENTIFY && key >= '0' && key <= '9') {
274 		wp = window_pane_at_index(w, key - '0');
275 		if (wp != NULL && window_pane_visible(wp))
276 			window_set_active_pane(w, wp);
277 		server_clear_identify(c);
278 		return;
279 	}
280 
281 	/* Handle status line. */
282 	status_message_clear(c);
283 	server_clear_identify(c);
284 	if (c->prompt_string != NULL) {
285 		status_prompt_key(c, key);
286 		return;
287 	}
288 
289 	/* Check for mouse keys. */
290 	if (key == KEYC_MOUSE) {
291 		if (options_get_number(oo, "mouse-select-pane")) {
292 			window_set_active_at(w, mouse->x, mouse->y);
293 			wp = w->active;
294 		}
295 		window_pane_mouse(wp, c, mouse);
296 		return;
297 	}
298 
299 	/* Is this a prefix key? */
300 	keylist = options_get_data(&c->session->options, "prefix");
301 	isprefix = 0;
302 	for (i = 0; i < ARRAY_LENGTH(keylist); i++) {
303 		if (key == ARRAY_ITEM(keylist, i)) {
304 			isprefix = 1;
305 			break;
306 		}
307 	}
308 
309 	/* No previous prefix key. */
310 	if (!(c->flags & CLIENT_PREFIX)) {
311 		if (isprefix)
312 			c->flags |= CLIENT_PREFIX;
313 		else {
314 			/* Try as a non-prefix key binding. */
315 			if ((bd = key_bindings_lookup(key)) == NULL)
316 				window_pane_key(wp, c, key);
317 			else
318 				key_bindings_dispatch(bd, c);
319 		}
320 		return;
321 	}
322 
323 	/* Prefix key already pressed. Reset prefix and lookup key. */
324 	c->flags &= ~CLIENT_PREFIX;
325 	if ((bd = key_bindings_lookup(key | KEYC_PREFIX)) == NULL) {
326 		/* If repeating, treat this as a key, else ignore. */
327 		if (c->flags & CLIENT_REPEAT) {
328 			c->flags &= ~CLIENT_REPEAT;
329 			if (isprefix)
330 				c->flags |= CLIENT_PREFIX;
331 			else
332 				window_pane_key(wp, c, key);
333 		}
334 		return;
335 	}
336 
337 	/* If already repeating, but this key can't repeat, skip it. */
338 	if (c->flags & CLIENT_REPEAT && !bd->can_repeat) {
339 		c->flags &= ~CLIENT_REPEAT;
340 		if (isprefix)
341 			c->flags |= CLIENT_PREFIX;
342 		else
343 			window_pane_key(wp, c, key);
344 		return;
345 	}
346 
347 	/* If this key can repeat, reset the repeat flags and timer. */
348 	xtimeout = options_get_number(&c->session->options, "repeat-time");
349 	if (xtimeout != 0 && bd->can_repeat) {
350 		c->flags |= CLIENT_PREFIX|CLIENT_REPEAT;
351 
352 		tv.tv_sec = xtimeout / 1000;
353 		tv.tv_usec = (xtimeout % 1000) * 1000L;
354 		evtimer_del(&c->repeat_timer);
355 		evtimer_add(&c->repeat_timer, &tv);
356 	}
357 
358 	/* Dispatch the command. */
359 	key_bindings_dispatch(bd, c);
360 }
361 
362 /* Client functions that need to happen every loop. */
363 void
364 server_client_loop(void)
365 {
366 	struct client		*c;
367 	struct window		*w;
368 	struct window_pane	*wp;
369 	u_int		 	 i;
370 
371 	for (i = 0; i < ARRAY_LENGTH(&clients); i++) {
372 		c = ARRAY_ITEM(&clients, i);
373 		if (c == NULL || c->session == NULL)
374 			continue;
375 
376 		server_client_check_redraw(c);
377 		server_client_reset_state(c);
378 	}
379 
380 	/*
381 	 * Any windows will have been redrawn as part of clients, so clear
382 	 * their flags now.
383 	 */
384 	for (i = 0; i < ARRAY_LENGTH(&windows); i++) {
385 		w = ARRAY_ITEM(&windows, i);
386 		if (w == NULL)
387 			continue;
388 
389 		w->flags &= ~WINDOW_REDRAW;
390 		TAILQ_FOREACH(wp, &w->panes, entry)
391 			wp->flags &= ~PANE_REDRAW;
392 	}
393 }
394 
395 /*
396  * Update cursor position and mode settings. The scroll region and attributes
397  * are cleared when idle (waiting for an event) as this is the most likely time
398  * a user may interrupt tmux, for example with ~^Z in ssh(1). This is a
399  * compromise between excessive resets and likelihood of an interrupt.
400  *
401  * tty_region/tty_reset/tty_update_mode already take care of not resetting
402  * things that are already in their default state.
403  */
404 void
405 server_client_reset_state(struct client *c)
406 {
407 	struct window		*w = c->session->curw->window;
408 	struct window_pane	*wp = w->active;
409 	struct screen		*s = wp->screen;
410 	struct options		*oo = &c->session->options;
411 	int			 status, mode;
412 
413 	tty_region(&c->tty, 0, c->tty.sy - 1);
414 
415 	status = options_get_number(oo, "status");
416 	if (!window_pane_visible(wp) || wp->yoff + s->cy >= c->tty.sy - status)
417 		tty_cursor(&c->tty, 0, 0);
418 	else
419 		tty_cursor(&c->tty, wp->xoff + s->cx, wp->yoff + s->cy);
420 
421 	mode = s->mode;
422 	if (TAILQ_NEXT(TAILQ_FIRST(&w->panes), entry) != NULL &&
423 	    options_get_number(oo, "mouse-select-pane"))
424 		mode |= MODE_MOUSE;
425 	tty_update_mode(&c->tty, mode);
426 	tty_reset(&c->tty);
427 }
428 
429 /* Repeat time callback. */
430 /* ARGSUSED */
431 void
432 server_client_repeat_timer(unused int fd, unused short events, void *data)
433 {
434 	struct client	*c = data;
435 
436 	if (c->flags & CLIENT_REPEAT)
437 		c->flags &= ~(CLIENT_PREFIX|CLIENT_REPEAT);
438 }
439 
440 /* Check for client redraws. */
441 void
442 server_client_check_redraw(struct client *c)
443 {
444 	struct session		*s = c->session;
445 	struct window_pane	*wp;
446 	int		 	 flags, redraw;
447 
448 	flags = c->tty.flags & TTY_FREEZE;
449 	c->tty.flags &= ~TTY_FREEZE;
450 
451 	if (c->flags & (CLIENT_REDRAW|CLIENT_STATUS)) {
452 		if (options_get_number(&s->options, "set-titles"))
453 			server_client_set_title(c);
454 
455 		if (c->message_string != NULL)
456 			redraw = status_message_redraw(c);
457 		else if (c->prompt_string != NULL)
458 			redraw = status_prompt_redraw(c);
459 		else
460 			redraw = status_redraw(c);
461 		if (!redraw)
462 			c->flags &= ~CLIENT_STATUS;
463 	}
464 
465 	if (c->flags & CLIENT_REDRAW) {
466 		screen_redraw_screen(c, 0);
467 		c->flags &= ~CLIENT_STATUS;
468 	} else {
469 		TAILQ_FOREACH(wp, &c->session->curw->window->panes, entry) {
470 			if (wp->flags & PANE_REDRAW)
471 				screen_redraw_pane(c, wp);
472 		}
473 	}
474 
475 	if (c->flags & CLIENT_STATUS)
476 		screen_redraw_screen(c, 1);
477 
478 	c->tty.flags |= flags;
479 
480 	c->flags &= ~(CLIENT_REDRAW|CLIENT_STATUS);
481 }
482 
483 /* Set client title. */
484 void
485 server_client_set_title(struct client *c)
486 {
487 	struct session	*s = c->session;
488 	const char	*template;
489 	char		*title;
490 
491 	template = options_get_string(&s->options, "set-titles-string");
492 
493 	title = status_replace(c, NULL, template, time(NULL), 1);
494 	if (c->title == NULL || strcmp(title, c->title) != 0) {
495 		if (c->title != NULL)
496 			xfree(c->title);
497 		c->title = xstrdup(title);
498 		tty_set_title(&c->tty, c->title);
499 	}
500 	xfree(title);
501 }
502 
503 /* Dispatch message from client. */
504 int
505 server_client_msg_dispatch(struct client *c)
506 {
507 	struct imsg		 imsg;
508 	struct msg_command_data	 commanddata;
509 	struct msg_identify_data identifydata;
510 	struct msg_environ_data	 environdata;
511 	ssize_t			 n, datalen;
512 
513 	if ((n = imsg_read(&c->ibuf)) == -1 || n == 0)
514 		return (-1);
515 
516 	for (;;) {
517 		if ((n = imsg_get(&c->ibuf, &imsg)) == -1)
518 			return (-1);
519 		if (n == 0)
520 			return (0);
521 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
522 
523 		if (imsg.hdr.peerid != PROTOCOL_VERSION) {
524 			server_write_client(c, MSG_VERSION, NULL, 0);
525 			c->flags |= CLIENT_BAD;
526 			imsg_free(&imsg);
527 			continue;
528 		}
529 
530 		log_debug("got %d from client %d", imsg.hdr.type, c->ibuf.fd);
531 		switch (imsg.hdr.type) {
532 		case MSG_COMMAND:
533 			if (datalen != sizeof commanddata)
534 				fatalx("bad MSG_COMMAND size");
535 			memcpy(&commanddata, imsg.data, sizeof commanddata);
536 
537 			server_client_msg_command(c, &commanddata);
538 			break;
539 		case MSG_IDENTIFY:
540 			if (datalen != sizeof identifydata)
541 				fatalx("bad MSG_IDENTIFY size");
542 			if (imsg.fd == -1)
543 				fatalx("MSG_IDENTIFY missing fd");
544 			memcpy(&identifydata, imsg.data, sizeof identifydata);
545 
546 			server_client_msg_identify(c, &identifydata, imsg.fd);
547 			break;
548 		case MSG_RESIZE:
549 			if (datalen != 0)
550 				fatalx("bad MSG_RESIZE size");
551 
552 			tty_resize(&c->tty);
553 			recalculate_sizes();
554 			server_redraw_client(c);
555 			break;
556 		case MSG_EXITING:
557 			if (datalen != 0)
558 				fatalx("bad MSG_EXITING size");
559 
560 			c->session = NULL;
561 			tty_close(&c->tty);
562 			server_write_client(c, MSG_EXITED, NULL, 0);
563 			break;
564 		case MSG_WAKEUP:
565 		case MSG_UNLOCK:
566 			if (datalen != 0)
567 				fatalx("bad MSG_WAKEUP size");
568 
569 			if (!(c->flags & CLIENT_SUSPENDED))
570 				break;
571 			c->flags &= ~CLIENT_SUSPENDED;
572 
573 			if (gettimeofday(&c->activity_time, NULL) != 0)
574 				fatal("gettimeofday");
575 			if (c->session != NULL) {
576 				memcpy(&c->session->activity_time,
577 				    &c->activity_time,
578 				    sizeof c->session->activity_time);
579 			}
580 
581 			tty_start_tty(&c->tty);
582 			server_redraw_client(c);
583 			recalculate_sizes();
584 			break;
585 		case MSG_ENVIRON:
586 			if (datalen != sizeof environdata)
587 				fatalx("bad MSG_ENVIRON size");
588 			memcpy(&environdata, imsg.data, sizeof environdata);
589 
590 			environdata.var[(sizeof environdata.var) - 1] = '\0';
591 			if (strchr(environdata.var, '=') != NULL)
592 				environ_put(&c->environ, environdata.var);
593 			break;
594 		case MSG_SHELL:
595 			if (datalen != 0)
596 				fatalx("bad MSG_SHELL size");
597 
598 			server_client_msg_shell(c);
599 			break;
600 		default:
601 			fatalx("unexpected message");
602 		}
603 
604 		imsg_free(&imsg);
605 	}
606 }
607 
608 /* Callback to send error message to client. */
609 void printflike2
610 server_client_msg_error(struct cmd_ctx *ctx, const char *fmt, ...)
611 {
612 	struct msg_print_data	data;
613 	va_list			ap;
614 
615 	va_start(ap, fmt);
616 	xvsnprintf(data.msg, sizeof data.msg, fmt, ap);
617 	va_end(ap);
618 
619 	server_write_client(ctx->cmdclient, MSG_ERROR, &data, sizeof data);
620 }
621 
622 /* Callback to send print message to client. */
623 void printflike2
624 server_client_msg_print(struct cmd_ctx *ctx, const char *fmt, ...)
625 {
626 	struct msg_print_data	data;
627 	va_list			ap;
628 
629 	va_start(ap, fmt);
630 	xvsnprintf(data.msg, sizeof data.msg, fmt, ap);
631 	va_end(ap);
632 
633 	server_write_client(ctx->cmdclient, MSG_PRINT, &data, sizeof data);
634 }
635 
636 /* Callback to send print message to client, if not quiet. */
637 void printflike2
638 server_client_msg_info(struct cmd_ctx *ctx, const char *fmt, ...)
639 {
640 	struct msg_print_data	data;
641 	va_list			ap;
642 
643 	if (options_get_number(&global_options, "quiet"))
644 		return;
645 
646 	va_start(ap, fmt);
647 	xvsnprintf(data.msg, sizeof data.msg, fmt, ap);
648 	va_end(ap);
649 
650 	server_write_client(ctx->cmdclient, MSG_PRINT, &data, sizeof data);
651 }
652 
653 /* Handle command message. */
654 void
655 server_client_msg_command(struct client *c, struct msg_command_data *data)
656 {
657 	struct cmd_ctx	 ctx;
658 	struct cmd_list	*cmdlist = NULL;
659 	struct cmd	*cmd;
660 	int		 argc;
661 	char	       **argv, *cause;
662 
663 	ctx.error = server_client_msg_error;
664 	ctx.print = server_client_msg_print;
665 	ctx.info = server_client_msg_info;
666 
667 	ctx.msgdata = data;
668 	ctx.curclient = NULL;
669 
670 	ctx.cmdclient = c;
671 
672 	argc = data->argc;
673 	data->argv[(sizeof data->argv) - 1] = '\0';
674 	if (cmd_unpack_argv(data->argv, sizeof data->argv, argc, &argv) != 0) {
675 		server_client_msg_error(&ctx, "command too long");
676 		goto error;
677 	}
678 
679 	if (argc == 0) {
680 		argc = 1;
681 		argv = xcalloc(1, sizeof *argv);
682 		*argv = xstrdup("new-session");
683 	}
684 
685 	if ((cmdlist = cmd_list_parse(argc, argv, &cause)) == NULL) {
686 		server_client_msg_error(&ctx, "%s", cause);
687 		cmd_free_argv(argc, argv);
688 		goto error;
689 	}
690 	cmd_free_argv(argc, argv);
691 
692 	if (data->pid != -1) {
693 		TAILQ_FOREACH(cmd, cmdlist, qentry) {
694 			if (cmd->entry->flags & CMD_CANTNEST) {
695 				server_client_msg_error(&ctx,
696 				    "sessions should be nested with care. "
697 				    "unset $TMUX to force");
698 				goto error;
699 			}
700 		}
701 	}
702 
703 	if (cmd_list_exec(cmdlist, &ctx) != 1)
704 		server_write_client(c, MSG_EXIT, NULL, 0);
705 	cmd_list_free(cmdlist);
706 	return;
707 
708 error:
709 	if (cmdlist != NULL)
710 		cmd_list_free(cmdlist);
711 	server_write_client(c, MSG_EXIT, NULL, 0);
712 }
713 
714 /* Handle identify message. */
715 void
716 server_client_msg_identify(
717     struct client *c, struct msg_identify_data *data, int fd)
718 {
719 	c->cwd = NULL;
720 	data->cwd[(sizeof data->cwd) - 1] = '\0';
721 	if (*data->cwd != '\0')
722 		c->cwd = xstrdup(data->cwd);
723 
724 	data->term[(sizeof data->term) - 1] = '\0';
725 	tty_init(&c->tty, fd, data->term);
726 	if (data->flags & IDENTIFY_UTF8)
727 		c->tty.flags |= TTY_UTF8;
728 	if (data->flags & IDENTIFY_256COLOURS)
729 		c->tty.term_flags |= TERM_256COLOURS;
730 	else if (data->flags & IDENTIFY_88COLOURS)
731 		c->tty.term_flags |= TERM_88COLOURS;
732 	c->tty.key_callback = server_client_handle_key;
733 	c->tty.key_data = c;
734 
735 	tty_resize(&c->tty);
736 
737 	c->flags |= CLIENT_TERMINAL;
738 }
739 
740 /* Handle shell message. */
741 void
742 server_client_msg_shell(struct client *c)
743 {
744 	struct msg_shell_data	 data;
745 	const char		*shell;
746 
747 	shell = options_get_string(&global_s_options, "default-shell");
748 
749 	if (*shell == '\0' || areshell(shell))
750 		shell = _PATH_BSHELL;
751 	if (strlcpy(data.shell, shell, sizeof data.shell) >= sizeof data.shell)
752 		strlcpy(data.shell, _PATH_BSHELL, sizeof data.shell);
753 
754 	server_write_client(c, MSG_SHELL, &data, sizeof data);
755 	c->flags |= CLIENT_BAD;	/* it will die after exec */
756 }
757