Return to server-client.c CVS log

Up to [local] / src / usr.bin / tmux

Add a skeleton mode to tmux (called "control mode") that let's tmux
commands be sent and output received on stdout. This can be used to
integrate with other terminal emulators and should allow some other
things to be made simpler later. More to come so doesn't do much yet and
deliberately not documented.

/* $OpenBSD: server-client.c,v 1.75 2012/06/18 13:16:42 nicm Exp $ */

/*
 * Copyright (c) 2009 Nicholas Marriott <nicm@users.sourceforge.net>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER
 * IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/types.h>

#include <event.h>
#include <fcntl.h>
#include <string.h>
#include <time.h>
#include <paths.h>
#include <unistd.h>

#include "tmux.h"

void	server_client_check_mouse(struct client *, struct window_pane *,
	    struct mouse_event *);
void	server_client_repeat_timer(int, short, void *);
void	server_client_check_exit(struct client *);
void	server_client_check_redraw(struct client *);
void	server_client_set_title(struct client *);
void	server_client_reset_state(struct client *);

int	server_client_msg_dispatch(struct client *);
void	server_client_msg_command(struct client *, struct msg_command_data *);
void	server_client_msg_identify(
	    struct client *, struct msg_identify_data *, int);
void	server_client_msg_shell(struct client *);

void printflike2 server_client_msg_error(struct cmd_ctx *, const char *, ...);
void printflike2 server_client_msg_print(struct cmd_ctx *, const char *, ...);
void printflike2 server_client_msg_info(struct cmd_ctx *, const char *, ...);

/* Create a new client. */
void
server_client_create(int fd)
{
	struct client	*c;
	u_int		 i;

	setblocking(fd, 0);

	c = xcalloc(1, sizeof *c);
	c->references = 0;
	imsg_init(&c->ibuf, fd);
	server_update_event(c);

	if (gettimeofday(&c->creation_time, NULL) != 0)
		fatal("gettimeofday failed");
	memcpy(&c->activity_time, &c->creation_time, sizeof c->activity_time);

	c->stdin_data = evbuffer_new ();
	c->stdout_data = evbuffer_new ();
	c->stderr_data = evbuffer_new ();

	c->tty.fd = -1;
	c->title = NULL;

	c->session = NULL;
	c->last_session = NULL;
	c->tty.sx = 80;
	c->tty.sy = 24;

	screen_init(&c->status, c->tty.sx, 1, 0);
	RB_INIT(&c->status_new);
	RB_INIT(&c->status_old);

	c->message_string = NULL;
	ARRAY_INIT(&c->message_log);

	c->prompt_string = NULL;
	c->prompt_buffer = NULL;
	c->prompt_index = 0;

	c->last_mouse.b = MOUSE_UP;
	c->last_mouse.x = c->last_mouse.y = -1;

	evtimer_set(&c->repeat_timer, server_client_repeat_timer, c);

	for (i = 0; i < ARRAY_LENGTH(&clients); i++) {
		if (ARRAY_ITEM(&clients, i) == NULL) {
			ARRAY_SET(&clients, i, c);
			return;
		}
	}
	ARRAY_ADD(&clients, c);
	log_debug("new client %d", fd);
}

/* Open client terminal if needed. */
int
server_client_open(struct client *c, struct session *s, char **cause)
{
	struct options	*oo = s != NULL ? &s->options : &global_s_options;
	char		*overrides;

	if (c->flags & CLIENT_CONTROL)
		return (0);

	if (!(c->flags & CLIENT_TERMINAL)) {
		*cause = xstrdup ("not a terminal");
		return (-1);
	}

	overrides = options_get_string(oo, "terminal-overrides");
	if (tty_open(&c->tty, overrides, cause) != 0)
		return (-1);

	return (0);
}

/* Lost a client. */
void
server_client_lost(struct client *c)
{
	struct message_entry	*msg;
	u_int			 i;

	for (i = 0; i < ARRAY_LENGTH(&clients); i++) {
		if (ARRAY_ITEM(&clients, i) == c)
			ARRAY_SET(&clients, i, NULL);
	}
	log_debug("lost client %d", c->ibuf.fd);

	/*
	 * If CLIENT_TERMINAL hasn't been set, then tty_init hasn't been called
	 * and tty_free might close an unrelated fd.
	 */
	if (c->flags & CLIENT_TERMINAL)
		tty_free(&c->tty);

	evbuffer_free (c->stdin_data);
	evbuffer_free (c->stdout_data);
	evbuffer_free (c->stderr_data);

	status_free_jobs(&c->status_new);
	status_free_jobs(&c->status_old);
	screen_free(&c->status);

	if (c->title != NULL)
		xfree(c->title);

	evtimer_del(&c->repeat_timer);

	if (event_initialized(&c->identify_timer))
		evtimer_del(&c->identify_timer);

	if (c->message_string != NULL)
		xfree(c->message_string);
	if (event_initialized (&c->message_timer))
		evtimer_del(&c->message_timer);
	for (i = 0; i < ARRAY_LENGTH(&c->message_log); i++) {
		msg = &ARRAY_ITEM(&c->message_log, i);
		xfree(msg->msg);
	}
	ARRAY_FREE(&c->message_log);

	if (c->prompt_string != NULL)
		xfree(c->prompt_string);
	if (c->prompt_buffer != NULL)
		xfree(c->prompt_buffer);

	if (c->cwd != NULL)
		xfree(c->cwd);

	environ_free(&c->environ);

	close(c->ibuf.fd);
	imsg_clear(&c->ibuf);
	if (event_initialized(&c->event))
		event_del(&c->event);

	for (i = 0; i < ARRAY_LENGTH(&dead_clients); i++) {
		if (ARRAY_ITEM(&dead_clients, i) == NULL) {
			ARRAY_SET(&dead_clients, i, c);
			break;
		}
	}
	if (i == ARRAY_LENGTH(&dead_clients))
		ARRAY_ADD(&dead_clients, c);
	c->flags |= CLIENT_DEAD;

	server_add_accept(0); /* may be more file descriptors now */

	recalculate_sizes();
	server_check_unattached();
	server_update_socket();
}

/* Process a single client event. */
void
server_client_callback(int fd, short events, void *data)
{
	struct client	*c = data;

	if (c->flags & CLIENT_DEAD)
		return;

	if (fd == c->ibuf.fd) {
		if (events & EV_WRITE && msgbuf_write(&c->ibuf.w) < 0)
			goto client_lost;

		if (c->flags & CLIENT_BAD) {
			if (c->ibuf.w.queued == 0)
				goto client_lost;
			return;
		}

		if (events & EV_READ && server_client_msg_dispatch(c) != 0)
			goto client_lost;
	}

	server_push_stdout(c);
	server_push_stderr(c);

	server_update_event(c);
	return;

client_lost:
	server_client_lost(c);
}

/* Handle client status timer. */
void
server_client_status_timer(void)
{
	struct client	*c;
	struct session	*s;
	struct timeval	 tv;
	u_int		 i;
	int		 interval;
	time_t		 difference;

	if (gettimeofday(&tv, NULL) != 0)
		fatal("gettimeofday failed");

	for (i = 0; i < ARRAY_LENGTH(&clients); i++) {
		c = ARRAY_ITEM(&clients, i);
		if (c == NULL || c->session == NULL)
			continue;
		if (c->message_string != NULL || c->prompt_string != NULL) {
			/*
			 * Don't need timed redraw for messages/prompts so bail
			 * now. The status timer isn't reset when they are
			 * redrawn anyway.
			 */
			continue;
		}
		s = c->session;

		if (!options_get_number(&s->options, "status"))
			continue;
		interval = options_get_number(&s->options, "status-interval");

		difference = tv.tv_sec - c->status_timer.tv_sec;
		if (difference >= interval) {
			status_update_jobs(c);
			c->flags |= CLIENT_STATUS;
		}
	}
}

/* Check for mouse keys. */
void
server_client_check_mouse(
    struct client *c, struct window_pane *wp, struct mouse_event *mouse)
{
	struct session	*s = c->session;
	struct options	*oo = &s->options;
	int		 statusat;

	statusat = status_at_line(c);

	/* Is this a window selection click on the status line? */
	if (statusat != -1 && mouse->y == (u_int)statusat &&
	    options_get_number(oo, "mouse-select-window")) {
		if (mouse->b == MOUSE_UP && c->last_mouse.b != MOUSE_UP) {
			status_set_window_at(c, mouse->x);
			recalculate_sizes();
			return;
		}
		if (mouse->b & MOUSE_45) {
			if ((mouse->b & MOUSE_BUTTON) == MOUSE_1) {
				session_previous(c->session, 0);
				server_redraw_session(s);
				recalculate_sizes();
			}
			if ((mouse->b & MOUSE_BUTTON) == MOUSE_2) {
				session_next(c->session, 0);
				server_redraw_session(s);
				recalculate_sizes();
			}
			return;
		}
		memcpy(&c->last_mouse, mouse, sizeof c->last_mouse);
		return;
	}

	/*
	 * Not on status line - adjust mouse position if status line is at the
	 * top and limit if at the bottom. From here on a struct mouse
	 * represents the offset onto the window itself.
	 */
	if (statusat == 0 &&mouse->y > 0)
		mouse->y--;
	else if (statusat > 0 && mouse->y >= (u_int)statusat)
		mouse->y = statusat - 1;

	/* Is this a pane selection? Allow down only in copy mode. */
	if (options_get_number(oo, "mouse-select-pane") &&
	    ((!(mouse->b & MOUSE_DRAG) && mouse->b != MOUSE_UP) ||
	    wp->mode != &window_copy_mode)) {
		window_set_active_at(wp->window, mouse->x, mouse->y);
		server_redraw_window_borders(wp->window);
		wp = wp->window->active; /* may have changed */
	}

	/* Check if trying to resize pane. */
	if (options_get_number(oo, "mouse-resize-pane"))
		layout_resize_pane_mouse(c, mouse);

	/* Update last and pass through to client. */
	memcpy(&c->last_mouse, mouse, sizeof c->last_mouse);
	window_pane_mouse(wp, c->session, mouse);
}

/* Handle data key input from client. */
void
server_client_handle_key(struct client *c, int key)
{
	struct session		*s;
	struct window		*w;
	struct window_pane	*wp;
	struct options		*oo;
	struct timeval		 tv;
	struct key_binding	*bd;
	int		      	 xtimeout, isprefix;

	/* Check the client is good to accept input. */
	if ((c->flags & (CLIENT_DEAD|CLIENT_SUSPENDED)) != 0)
		return;
	if (c->session == NULL)
		return;
	s = c->session;

	/* Update the activity timer. */
	if (gettimeofday(&c->activity_time, NULL) != 0)
		fatal("gettimeofday failed");
	memcpy(&s->activity_time, &c->activity_time, sizeof s->activity_time);

	w = c->session->curw->window;
	wp = w->active;
	oo = &c->session->options;

	/* Special case: number keys jump to pane in identify mode. */
	if (c->flags & CLIENT_IDENTIFY && key >= '0' && key <= '9') {
		if (c->flags & CLIENT_READONLY)
			return;
		wp = window_pane_at_index(w, key - '0');
		if (wp != NULL && window_pane_visible(wp))
			window_set_active_pane(w, wp);
		server_clear_identify(c);
		return;
	}

	/* Handle status line. */
	if (!(c->flags & CLIENT_READONLY)) {
		status_message_clear(c);
		server_clear_identify(c);
	}
	if (c->prompt_string != NULL) {
		if (!(c->flags & CLIENT_READONLY))
			status_prompt_key(c, key);
		return;
	}

	/* Check for mouse keys. */
	if (key == KEYC_MOUSE) {
		if (c->flags & CLIENT_READONLY)
			return;
		server_client_check_mouse(c, wp, &c->tty.mouse);
		return;
	}

	/* Is this a prefix key? */
	if (key == options_get_number(&c->session->options, "prefix"))
		isprefix = 1;
	else if (key == options_get_number(&c->session->options, "prefix2"))
		isprefix = 1;
	else
		isprefix = 0;

	/* No previous prefix key. */
	if (!(c->flags & CLIENT_PREFIX)) {
		if (isprefix)
			c->flags |= CLIENT_PREFIX;
		else {
			/* Try as a non-prefix key binding. */
			if ((bd = key_bindings_lookup(key)) == NULL) {
				if (!(c->flags & CLIENT_READONLY))
					window_pane_key(wp, c->session, key);
			} else
				key_bindings_dispatch(bd, c);
		}
		return;
	}

	/* Prefix key already pressed. Reset prefix and lookup key. */
	c->flags &= ~CLIENT_PREFIX;
	if ((bd = key_bindings_lookup(key | KEYC_PREFIX)) == NULL) {
		/* If repeating, treat this as a key, else ignore. */
		if (c->flags & CLIENT_REPEAT) {
			c->flags &= ~CLIENT_REPEAT;
			if (isprefix)
				c->flags |= CLIENT_PREFIX;
			else if (!(c->flags & CLIENT_READONLY))
				window_pane_key(wp, c->session, key);
		}
		return;
	}

	/* If already repeating, but this key can't repeat, skip it. */
	if (c->flags & CLIENT_REPEAT && !bd->can_repeat) {
		c->flags &= ~CLIENT_REPEAT;
		if (isprefix)
			c->flags |= CLIENT_PREFIX;
		else if (!(c->flags & CLIENT_READONLY))
			window_pane_key(wp, c->session, key);
		return;
	}

	/* If this key can repeat, reset the repeat flags and timer. */
	xtimeout = options_get_number(&c->session->options, "repeat-time");
	if (xtimeout != 0 && bd->can_repeat) {
		c->flags |= CLIENT_PREFIX|CLIENT_REPEAT;

		tv.tv_sec = xtimeout / 1000;
		tv.tv_usec = (xtimeout % 1000) * 1000L;
		evtimer_del(&c->repeat_timer);
		evtimer_add(&c->repeat_timer, &tv);
	}

	/* Dispatch the command. */
	key_bindings_dispatch(bd, c);
}

/* Client functions that need to happen every loop. */
void
server_client_loop(void)
{
	struct client		*c;
	struct window		*w;
	struct window_pane	*wp;
	u_int		 	 i;

	for (i = 0; i < ARRAY_LENGTH(&clients); i++) {
		c = ARRAY_ITEM(&clients, i);
		if (c == NULL)
			continue;

		server_client_check_exit(c);
		if (c->session != NULL) {
			server_client_check_redraw(c);
			server_client_reset_state(c);
		}
	}

	/*
	 * Any windows will have been redrawn as part of clients, so clear
	 * their flags now.
	 */
	for (i = 0; i < ARRAY_LENGTH(&windows); i++) {
		w = ARRAY_ITEM(&windows, i);
		if (w == NULL)
			continue;

		w->flags &= ~WINDOW_REDRAW;
		TAILQ_FOREACH(wp, &w->panes, entry)
			wp->flags &= ~PANE_REDRAW;
	}
}

/*
 * Update cursor position and mode settings. The scroll region and attributes
 * are cleared when idle (waiting for an event) as this is the most likely time
 * a user may interrupt tmux, for example with ~^Z in ssh(1). This is a
 * compromise between excessive resets and likelihood of an interrupt.
 *
 * tty_region/tty_reset/tty_update_mode already take care of not resetting
 * things that are already in their default state.
 */
void
server_client_reset_state(struct client *c)
{
	struct window		*w = c->session->curw->window;
	struct window_pane	*wp = w->active;
	struct screen		*s = wp->screen;
	struct options		*oo = &c->session->options;
	struct options		*wo = &w->options;
	int			 status, mode, o;

	if (c->flags & CLIENT_SUSPENDED)
		return;

	tty_region(&c->tty, 0, c->tty.sy - 1);

	status = options_get_number(oo, "status");
	if (!window_pane_visible(wp) || wp->yoff + s->cy >= c->tty.sy - status)
		tty_cursor(&c->tty, 0, 0);
	else {
		o = status && options_get_number (oo, "status-position") == 0;
		tty_cursor(&c->tty, wp->xoff + s->cx, o + wp->yoff + s->cy);
	}

	/*
	 * Resizing panes with the mouse requires at least button mode to give
	 * a smooth appearance.
	 */
	mode = s->mode;
	if ((c->last_mouse.b & MOUSE_RESIZE_PANE) &&
	    !(mode & (MODE_MOUSE_BUTTON|MODE_MOUSE_ANY)))
		mode |= MODE_MOUSE_BUTTON;

	/*
	 * Any mode will do for mouse-select-pane, but set standard mode if
	 * none.
	 */
	if ((mode & ALL_MOUSE_MODES) == 0) {
		if (TAILQ_NEXT(TAILQ_FIRST(&w->panes), entry) != NULL &&
		    options_get_number(oo, "mouse-select-pane"))
			mode |= MODE_MOUSE_STANDARD;
		else if (options_get_number(oo, "mouse-resize-pane"))
			mode |= MODE_MOUSE_STANDARD;
		else if (options_get_number(oo, "mouse-select-window"))
			mode |= MODE_MOUSE_STANDARD;
		else if (options_get_number(wo, "mode-mouse"))
			mode |= MODE_MOUSE_STANDARD;
	}

	/*
	 * Set UTF-8 mouse input if required. If the terminal is UTF-8, the
	 * user has set mouse-utf8 and any mouse mode is in effect, turn on
	 * UTF-8 mouse input. If the receiving terminal hasn't requested it
	 * (that is, it isn't in s->mode), then it'll be converted in
	 * input_mouse.
	 */
	if ((c->tty.flags & TTY_UTF8) &&
	    (mode & ALL_MOUSE_MODES) && options_get_number(oo, "mouse-utf8"))
		mode |= MODE_MOUSE_UTF8;
	else
		mode &= ~MODE_MOUSE_UTF8;

	/* Set the terminal mode and reset attributes. */
	tty_update_mode(&c->tty, mode, s);
	tty_reset(&c->tty);
}

/* Repeat time callback. */
/* ARGSUSED */
void
server_client_repeat_timer(unused int fd, unused short events, void *data)
{
	struct client	*c = data;

	if (c->flags & CLIENT_REPEAT)
		c->flags &= ~(CLIENT_PREFIX|CLIENT_REPEAT);
}

/* Check if client should be exited. */
void
server_client_check_exit(struct client *c)
{
	struct msg_exit_data	exitdata;

	if (!(c->flags & CLIENT_EXIT))
		return;

	if (EVBUFFER_LENGTH(c->stdin_data) != 0)
		return;
	if (EVBUFFER_LENGTH(c->stdout_data) != 0)
		return;
	if (EVBUFFER_LENGTH(c->stderr_data) != 0)
		return;

	exitdata.retcode = c->retcode;
	server_write_client(c, MSG_EXIT, &exitdata, sizeof exitdata);

	c->flags &= ~CLIENT_EXIT;
}

/* Check for client redraws. */
void
server_client_check_redraw(struct client *c)
{
	struct session		*s = c->session;
	struct window_pane	*wp;
	int		 	 flags, redraw;

	flags = c->tty.flags & TTY_FREEZE;
	c->tty.flags &= ~TTY_FREEZE;

	if (c->flags & (CLIENT_REDRAW|CLIENT_STATUS)) {
		if (options_get_number(&s->options, "set-titles"))
			server_client_set_title(c);

		if (c->message_string != NULL)
			redraw = status_message_redraw(c);
		else if (c->prompt_string != NULL)
			redraw = status_prompt_redraw(c);
		else
			redraw = status_redraw(c);
		if (!redraw)
			c->flags &= ~CLIENT_STATUS;
	}

	if (c->flags & CLIENT_REDRAW) {
		screen_redraw_screen(c, 0, 0);
		c->flags &= ~(CLIENT_STATUS|CLIENT_BORDERS);
	} else if (c->flags & CLIENT_REDRAWWINDOW) {
		TAILQ_FOREACH(wp, &c->session->curw->window->panes, entry)
			screen_redraw_pane(c, wp);
		c->flags &= ~CLIENT_REDRAWWINDOW;
	} else {
		TAILQ_FOREACH(wp, &c->session->curw->window->panes, entry) {
			if (wp->flags & PANE_REDRAW)
				screen_redraw_pane(c, wp);
		}
	}

	if (c->flags & CLIENT_BORDERS)
		screen_redraw_screen(c, 0, 1);

	if (c->flags & CLIENT_STATUS)
		screen_redraw_screen(c, 1, 0);

	c->tty.flags |= flags;

	c->flags &= ~(CLIENT_REDRAW|CLIENT_STATUS|CLIENT_BORDERS);
}

/* Set client title. */
void
server_client_set_title(struct client *c)
{
	struct session	*s = c->session;
	const char	*template;
	char		*title;

	template = options_get_string(&s->options, "set-titles-string");

	title = status_replace(c, NULL, NULL, NULL, template, time(NULL), 1);
	if (c->title == NULL || strcmp(title, c->title) != 0) {
		if (c->title != NULL)
			xfree(c->title);
		c->title = xstrdup(title);
		tty_set_title(&c->tty, c->title);
	}
	xfree(title);
}

/* Dispatch message from client. */
int
server_client_msg_dispatch(struct client *c)
{
	struct imsg		 imsg;
	struct msg_command_data	 commanddata;
	struct msg_identify_data identifydata;
	struct msg_environ_data	 environdata;
	struct msg_stdin_data	 stdindata;
	ssize_t			 n, datalen;

	if ((n = imsg_read(&c->ibuf)) == -1 || n == 0)
		return (-1);

	for (;;) {
		if ((n = imsg_get(&c->ibuf, &imsg)) == -1)
			return (-1);
		if (n == 0)
			return (0);
		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;

		if (imsg.hdr.peerid != PROTOCOL_VERSION) {
			server_write_client(c, MSG_VERSION, NULL, 0);
			c->flags |= CLIENT_BAD;
			imsg_free(&imsg);
			continue;
		}

		log_debug("got %d from client %d", imsg.hdr.type, c->ibuf.fd);
		switch (imsg.hdr.type) {
		case MSG_COMMAND:
			if (datalen != sizeof commanddata)
				fatalx("bad MSG_COMMAND size");
			memcpy(&commanddata, imsg.data, sizeof commanddata);

			server_client_msg_command(c, &commanddata);
			break;
		case MSG_IDENTIFY:
			if (datalen != sizeof identifydata)
				fatalx("bad MSG_IDENTIFY size");
			if (imsg.fd == -1)
				fatalx("MSG_IDENTIFY missing fd");
			memcpy(&identifydata, imsg.data, sizeof identifydata);

			server_client_msg_identify(c, &identifydata, imsg.fd);
			break;
		case MSG_STDIN:
			if (datalen != sizeof stdindata)
				fatalx("bad MSG_STDIN size");
			memcpy(&stdindata, imsg.data, sizeof stdindata);

			if (c->stdin_callback == NULL)
				break;
			if (stdindata.size <= 0)
				c->stdin_closed = 1;
			else {
				evbuffer_add(c->stdin_data, stdindata.data,
				    stdindata.size);
			}
			c->stdin_callback(c, c->stdin_closed,
			    c->stdin_callback_data);
			break;
		case MSG_RESIZE:
			if (datalen != 0)
				fatalx("bad MSG_RESIZE size");

			if (tty_resize(&c->tty)) {
				recalculate_sizes();
				server_redraw_client(c);
			}
			break;
		case MSG_EXITING:
			if (datalen != 0)
				fatalx("bad MSG_EXITING size");

			c->session = NULL;
			tty_close(&c->tty);
			server_write_client(c, MSG_EXITED, NULL, 0);
			break;
		case MSG_WAKEUP:
		case MSG_UNLOCK:
			if (datalen != 0)
				fatalx("bad MSG_WAKEUP size");

			if (!(c->flags & CLIENT_SUSPENDED))
				break;
			c->flags &= ~CLIENT_SUSPENDED;

			if (gettimeofday(&c->activity_time, NULL) != 0)
				fatal("gettimeofday");
			if (c->session != NULL)
				session_update_activity(c->session);

			tty_start_tty(&c->tty);
			server_redraw_client(c);
			recalculate_sizes();
			break;
		case MSG_ENVIRON:
			if (datalen != sizeof environdata)
				fatalx("bad MSG_ENVIRON size");
			memcpy(&environdata, imsg.data, sizeof environdata);

			environdata.var[(sizeof environdata.var) - 1] = '\0';
			if (strchr(environdata.var, '=') != NULL)
				environ_put(&c->environ, environdata.var);
			break;
		case MSG_SHELL:
			if (datalen != 0)
				fatalx("bad MSG_SHELL size");

			server_client_msg_shell(c);
			break;
		default:
			fatalx("unexpected message");
		}

		imsg_free(&imsg);
	}
}

/* Callback to send error message to client. */
void printflike2
server_client_msg_error(struct cmd_ctx *ctx, const char *fmt, ...)
{
	va_list	ap;

	va_start(ap, fmt);
	evbuffer_add_vprintf(ctx->cmdclient->stderr_data, fmt, ap);
	va_end(ap);

	evbuffer_add(ctx->cmdclient->stderr_data, "\n", 1);
	server_push_stderr(ctx->cmdclient);
	ctx->cmdclient->retcode = 1;
}

/* Callback to send print message to client. */
void printflike2
server_client_msg_print(struct cmd_ctx *ctx, const char *fmt, ...)
{
	va_list	ap;

	va_start(ap, fmt);
	evbuffer_add_vprintf(ctx->cmdclient->stdout_data, fmt, ap);
	va_end(ap);

	evbuffer_add(ctx->cmdclient->stdout_data, "\n", 1);
	server_push_stdout(ctx->cmdclient);
}

/* Callback to send print message to client, if not quiet. */
void printflike2
server_client_msg_info(struct cmd_ctx *ctx, const char *fmt, ...)
{
	va_list	ap;

	if (options_get_number(&global_options, "quiet"))
		return;

	va_start(ap, fmt);
	evbuffer_add_vprintf(ctx->cmdclient->stdout_data, fmt, ap);
	va_end(ap);

	evbuffer_add(ctx->cmdclient->stdout_data, "\n", 1);
	server_push_stdout(ctx->cmdclient);
}

/* Handle command message. */
void
server_client_msg_command(struct client *c, struct msg_command_data *data)
{
	struct cmd_ctx	 ctx;
	struct cmd_list	*cmdlist = NULL;
	int		 argc;
	char	       **argv, *cause;

	ctx.error = server_client_msg_error;
	ctx.print = server_client_msg_print;
	ctx.info = server_client_msg_info;

	ctx.msgdata = data;
	ctx.curclient = NULL;

	ctx.cmdclient = c;

	argc = data->argc;
	data->argv[(sizeof data->argv) - 1] = '\0';
	if (cmd_unpack_argv(data->argv, sizeof data->argv, argc, &argv) != 0) {
		server_client_msg_error(&ctx, "command too long");
		goto error;
	}

	if (argc == 0) {
		argc = 1;
		argv = xcalloc(1, sizeof *argv);
		*argv = xstrdup("new-session");
	}

	if ((cmdlist = cmd_list_parse(argc, argv, &cause)) == NULL) {
		server_client_msg_error(&ctx, "%s", cause);
		cmd_free_argv(argc, argv);
		goto error;
	}
	cmd_free_argv(argc, argv);

	if (cmd_list_exec(cmdlist, &ctx) != 1)
		c->flags |= CLIENT_EXIT;
	cmd_list_free(cmdlist);
	return;

error:
	if (cmdlist != NULL)
		cmd_list_free(cmdlist);
	c->flags |= CLIENT_EXIT;
}

/* Handle identify message. */
void
server_client_msg_identify(
    struct client *c, struct msg_identify_data *data, int fd)
{
	c->cwd = NULL;
	data->cwd[(sizeof data->cwd) - 1] = '\0';
	if (*data->cwd != '\0')
		c->cwd = xstrdup(data->cwd);

	if (data->flags & IDENTIFY_CONTROL) {
		c->stdin_callback = control_callback;
		c->flags |= (CLIENT_CONTROL|CLIENT_SUSPENDED);

		c->tty.fd = -1;
		c->tty.log_fd = -1;

		close(fd);
		return;
	}

	if (!isatty(fd))
	    return;
	data->term[(sizeof data->term) - 1] = '\0';
	tty_init(&c->tty, c, fd, data->term);
	if (data->flags & IDENTIFY_UTF8)
		c->tty.flags |= TTY_UTF8;
	if (data->flags & IDENTIFY_256COLOURS)
		c->tty.term_flags |= TERM_256COLOURS;
	else if (data->flags & IDENTIFY_88COLOURS)
		c->tty.term_flags |= TERM_88COLOURS;

	tty_resize(&c->tty);

	c->flags |= CLIENT_TERMINAL;
}

/* Handle shell message. */
void
server_client_msg_shell(struct client *c)
{
	struct msg_shell_data	 data;
	const char		*shell;

	shell = options_get_string(&global_s_options, "default-shell");

	if (*shell == '\0' || areshell(shell))
		shell = _PATH_BSHELL;
	if (strlcpy(data.shell, shell, sizeof data.shell) >= sizeof data.shell)
		strlcpy(data.shell, _PATH_BSHELL, sizeof data.shell);

	server_write_client(c, MSG_SHELL, &data, sizeof data);
	c->flags |= CLIENT_BAD;	/* it will die after exec */
}