server.c - tmux - Rivoreo Source Code Repositories

 /* $Id: server.c,v 1.67 2008-06-18 19:34:50 nicm Exp $ */

 /*
  * Copyright (c) 2007 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 <sys/ioctl.h>
 #include <sys/socket.h>
 #include <sys/stat.h>
 #include <sys/un.h>

 #include <errno.h>
 #include <fcntl.h>
 #include <poll.h>
 #include <signal.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <syslog.h>
 #include <termios.h>
 #include <time.h>
 #include <unistd.h>

 #include "tmux.h"

 /*
  * Main server functions.
  */

 /* Client list. */
 struct clients	 clients;

 int		 server_main(const char *, int);
 void		 server_fill_windows(struct pollfd **);
 void		 server_handle_windows(struct pollfd **);
 void		 server_fill_clients(struct pollfd **);
 void		 server_handle_clients(struct pollfd **);
 struct client	*server_accept_client(int);
 void		 server_handle_client(struct client *);
 void		 server_handle_window(struct window *);
 void		 server_lost_client(struct client *);
 void	 	 server_lost_window(struct window *);
 void		 server_check_redraw(struct client *);
 void		 server_check_status(struct client *);
 void		 server_update_socket(const char *);

 /* Fork new server. */
 int
 server_start(const char *path)
 {
 	struct sockaddr_un	sa;
 	size_t			size;
 	mode_t			mask;
 	int		   	n, fd, pair[2], mode;
 	char		       *cause;
 	u_char			ch;

 	/* Make a little socketpair to wait for the server to be ready. */
 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pair) != 0)
 		fatal("socketpair failed");

 	switch (fork()) {
 	case -1:
 		fatal("fork failed");
 	case 0:
 		break;
 	default:
 		close(pair[1]);

 		ch = 0x00;
 		if (read(pair[0], &ch, 1) == 1 && ch == 0xff) {
 			close(pair[0]);
 			return (0);
 		}
 		ch = 0x00;
 		if (write(pair[1], &ch, 1) != 1)
 			fatal("write failed");
 		close(pair[0]);
 		return (1);
 	}
 	close(pair[0]);

 #ifdef DEBUG
 	xmalloc_clear();
 #endif

 	/*
 	 * Must daemonise before loading configuration as the PID changes so
 	 * $TMUX would be wrong for sessions created in the config file.
 	 */
 	if (daemon(1, 1) != 0)
 		fatal("daemon failed");

 	ARRAY_INIT(&windows);
 	ARRAY_INIT(&clients);
 	ARRAY_INIT(&sessions);
 	key_bindings_init();

 	if (cfg_file != NULL && load_cfg(cfg_file, &cause) != 0) {
 		log_warnx("%s", cause);
 		exit(1);
 	}

 	logfile("server");
 #ifndef NO_SETPROCTITLE
 	setproctitle("server (%s)", path);
 #endif
 	log_debug("server started, pid %ld", (long) getpid());

 	memset(&sa, 0, sizeof sa);
 	sa.sun_family = AF_UNIX;
 	size = strlcpy(sa.sun_path, path, sizeof sa.sun_path);
 	if (size >= sizeof sa.sun_path) {
 		errno = ENAMETOOLONG;
 		fatal("socket failed");
 	}
 	unlink(sa.sun_path);

 	if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1)
 		fatal("socket failed");

 	mask = umask(S_IXUSR|S_IRWXG|S_IRWXO);
 	if (bind(fd, (struct sockaddr *) &sa, SUN_LEN(&sa)) == -1)
 		fatal("bind failed");
 	umask(mask);

 	if (listen(fd, 16) == -1)
 		fatal("listen failed");

 	if ((mode = fcntl(fd, F_GETFL)) == -1)
 		fatal("fcntl failed");
 	if (fcntl(fd, F_SETFL, mode|O_NONBLOCK) == -1)
 		fatal("fcntl failed");
 	if (fcntl(fd, F_SETFD, FD_CLOEXEC) == -1)
 		fatal("fcntl failed");

 	ch = 0xff;
 	if (write(pair[1], &ch, 1) != 1)
 		fatal("write failed");
 	read(pair[1], &ch, 1); /* Ignore errors; just to wait before closing. */
 	close(pair[1]);

 	n = server_main(path, fd);
 #ifdef DEBUG
 	xmalloc_report(getpid(), "server");
 #endif
 	exit(n);
 }

 /* Main server loop. */
 int
 server_main(const char *srv_path, int srv_fd)
 {
 	struct pollfd	*pfds, *pfd;
 	int		 nfds;
 	u_int		 i, n;

 	siginit();

 	pfds = NULL;
 	while (!sigterm) {
 		/* Initialise pollfd array. */
 		nfds = 1 + ARRAY_LENGTH(&windows) + ARRAY_LENGTH(&clients) * 2;
 		pfds = xrealloc(pfds, nfds, sizeof *pfds);
 		pfd = pfds;

 		/* Fill server socket. */
 		pfd->fd = srv_fd;
 		pfd->events = POLLIN;
 		pfd++;

 		/* Fill window and client sockets. */
 		server_fill_windows(&pfd);
 		server_fill_clients(&pfd);

 		/* Do the poll. */
 		log_debug("polling %d fds", nfds);
 		if ((nfds = poll(pfds, nfds, 500)) == -1) {
 			if (errno == EAGAIN || errno == EINTR)
 				continue;
 			fatal("poll failed");
 		}
 		pfd = pfds;
 		log_debug("poll returned %d", nfds);

 		/* Handle server socket. */
 		if (pfd->revents & (POLLERR|POLLNVAL|POLLHUP))
 			fatalx("lost server socket");
 		if (pfd->revents & POLLIN) {
 			server_accept_client(srv_fd);
 			continue;
 		}
 		pfd++;

 		/*
 		 * Handle window and client sockets. Clients can create
 		 * windows, so windows must come first to avoid messing up by
 		 * increasing the array size.
 		 */
 		server_handle_windows(&pfd);
 		server_handle_clients(&pfd);

 		/* Update socket permissions. */
 		server_update_socket(srv_path);

 		/*
 		 * If we have no sessions and clients left, let's get out
 		 * of here...
 		 */
 		n = 0;
 		for (i = 0; i < ARRAY_LENGTH(&sessions); i++) {
 			if (ARRAY_ITEM(&sessions, i) != NULL)
 				n++;
 		}
 		for (i = 0; i < ARRAY_LENGTH(&clients); i++) {
 			if (ARRAY_ITEM(&clients, i) != NULL)
 				n++;
 		}
 		if (n == 0)
 			break;
 	}
 	if (pfds != NULL)
 		xfree(pfds);

 	for (i = 0; i < ARRAY_LENGTH(&sessions); i++) {
 		if (ARRAY_ITEM(&sessions, i) != NULL)
 			session_destroy(ARRAY_ITEM(&sessions, i));
 	}
 	ARRAY_FREE(&sessions);

 	for (i = 0; i < ARRAY_LENGTH(&clients); i++) {
 		if (ARRAY_ITEM(&clients, i) != NULL)
 			server_lost_client(ARRAY_ITEM(&clients, i));
 	}
 	ARRAY_FREE(&clients);

 	key_bindings_free();

 	close(srv_fd);
 	unlink(srv_path);

 	return (0);
 }

 /* Fill window pollfds. */
 void
 server_fill_windows(struct pollfd **pfd)
 {
 	struct window	*w;
 	u_int		 i;

 	for (i = 0; i < ARRAY_LENGTH(&windows); i++) {
 		if ((w = ARRAY_ITEM(&windows, i)) == NULL)
 			(*pfd)->fd = -1;
 		else {
 			(*pfd)->fd = w->fd;
 			(*pfd)->events = POLLIN;
 			if (BUFFER_USED(w->out) > 0)
 				(*pfd)->events |= POLLOUT;
 			log_debug("adding window %d (%d)", (*pfd)->fd, w->fd);
 		}
 		(*pfd)++;
 	}
 }

 /* Handle window pollfds. */
 void
 server_handle_windows(struct pollfd **pfd)
 {
 	struct window	*w;
 	u_int		 i;

 	for (i = 0; i < ARRAY_LENGTH(&windows); i++) {
 		if ((w = ARRAY_ITEM(&windows, i)) != NULL) {
 			log_debug("testing window %d (%d)", (*pfd)->fd, w->fd);
 			if (buffer_poll(*pfd, w->in, w->out) != 0)
 				server_lost_window(w);
 			else
 				server_handle_window(w);
 		}
 		(*pfd)++;
 	}
 }

 /* Check for general redraw on client. */
 void
 server_check_redraw(struct client *c)
 {
 	struct session		       *s;
 	struct screen_redraw_ctx	ctx;
 	struct screen			screen;
 	u_int				xx, yy, sx, sy;
 	char			        title[BUFSIZ];

 	if (c == NULL || c->session == NULL)
 		return;
 	s = c->session;

 	if (options_get_number(&s->options, "set-titles")) {
 		xsnprintf(title, sizeof title,
 		    "%s:%u:%s - \"%s\"", s->name, s->curw->idx,
 		    s->curw->window->name, s->curw->window->base.title);
 		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);
 		}
 	}

 	xx = c->sx;
 	yy = c->sy - options_get_number(&s->options, "status-lines");
 	if (c->flags & CLIENT_REDRAW) {
 		sx = screen_size_x(s->curw->window->screen);
 		sy = screen_size_y(s->curw->window->screen);
 		if (sx < xx || sy < yy) {
 			/*
 			 * Fake up a blank(ish) screen and use it to draw the
 			 * empty regions. NOTE: because this uses
 			 * tty_write_client but doesn't write the client's
 			 * screen, this can't use anything which relies on
 			 * cursor position.
 			 */
 			screen_create(&screen, xx, yy, 0);
 			screen_redraw_start(&ctx, &screen, tty_write_client, c);
 			if (sx < xx)
 				screen_redraw_columns(&ctx, sx, xx - sx);
 			if (sy < yy)  {
 				screen_fill_area(&screen,
 				    0, sy, xx, 1, '-', 0, 0x70);
 				screen_redraw_lines(&ctx, sy, yy - sy);
 			}
 			screen_redraw_stop(&ctx);
 			screen_destroy(&screen);
 		}

 		screen_redraw_start_client(&ctx, c);
 		screen_redraw_lines(&ctx, 0, screen_size_y(ctx.s));
 		screen_redraw_stop(&ctx);

 		status_redraw(c);
 	} else if (c->flags & CLIENT_STATUS)
 		status_redraw(c);

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

 /* Check for status line redraw on client. */
 void
 server_check_status(struct client *c)
 {
 	struct timespec	 ts;
 	u_int		 nlines, interval;

 	if (c == NULL || c->session == NULL)
 		return;

 	nlines = options_get_number(&c->session->options, "status-lines");
 	interval = options_get_number(&c->session->options, "status-interval");
 	if (nlines == 0 || interval == 0)
 		return;

 	if (clock_gettime(CLOCK_REALTIME, &ts) != 0)
 		fatal("clock_gettime");
 	ts.tv_sec -= interval;

 	if (timespeccmp(&c->status_ts, &ts, <))
 		c->flags |= CLIENT_STATUS;
 }

 /* Fill client pollfds. */
 void
 server_fill_clients(struct pollfd **pfd)
 {
 	struct client	*c;
 	u_int		 i;

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

 		server_check_redraw(c);
 		server_check_status(c);

 		if (c == NULL)
 			(*pfd)->fd = -1;
 		else {
 			(*pfd)->fd = c->fd;
 			(*pfd)->events = POLLIN;
 			if (BUFFER_USED(c->out) > 0)
 				(*pfd)->events |= POLLOUT;
 			log_debug("adding client %d (%d)", (*pfd)->fd, c->fd);
 		}
 		(*pfd)++;

 		if (c == NULL || c->tty.fd == -1 || c->session == NULL)
 			(*pfd)->fd = -1;
 		else {
 			(*pfd)->fd = c->tty.fd;
 			(*pfd)->events = POLLIN;
 			if (BUFFER_USED(c->tty.out) > 0)
 				(*pfd)->events |= POLLOUT;
 			log_debug("adding tty %d (%d)", (*pfd)->fd, c->tty.fd);
 		}
 		(*pfd)++;
 	}
 }

 /* Handle client pollfds. */
 void
 server_handle_clients(struct pollfd **pfd)
 {
 	struct client	*c;
 	u_int		 i;

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

 		if (c != NULL) {
 			log_debug("testing client %d (%d)", (*pfd)->fd, c->fd);
 			if (buffer_poll(*pfd, c->in, c->out) != 0) {
 				server_lost_client(c);
 				(*pfd) += 2;
 				continue;
 			} else
 				server_msg_dispatch(c);
 		}
 		(*pfd)++;

 		if (c != NULL && c->tty.fd != -1 && c->session != NULL) {
 			log_debug("testing tty %d (%d)", (*pfd)->fd, c->tty.fd);
 			if (buffer_poll(*pfd, c->tty.in, c->tty.out) != 0)
 				server_lost_client(c);
 			else
 				server_handle_client(c);
 		}
 		(*pfd)++;
 	}
 }

 /* accept(2) and create new client. */
 struct client *
 server_accept_client(int srv_fd)
 {
 	struct client	       *c;
 	struct sockaddr_storage	sa;
 	socklen_t		slen = sizeof sa;
 	int		 	client_fd, mode;
 	u_int			i;

 	client_fd = accept(srv_fd, (struct sockaddr *) &sa, &slen);
 	if (client_fd == -1) {
 		if (errno == EAGAIN || errno == EINTR || errno == ECONNABORTED)
 			return (NULL);
 		fatal("accept failed");
 	}
 	if ((mode = fcntl(client_fd, F_GETFL)) == -1)
 		fatal("fcntl failed");
 	if (fcntl(client_fd, F_SETFL, mode|O_NONBLOCK) == -1)
 		fatal("fcntl failed");

 	c = xcalloc(1, sizeof *c);
 	c->fd = client_fd;
 	c->in = buffer_create(BUFSIZ);
 	c->out = buffer_create(BUFSIZ);

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

 	c->session = NULL;
 	c->sx = 80;
 	c->sy = 25;

 	for (i = 0; i < ARRAY_LENGTH(&clients); i++) {
 		if (ARRAY_ITEM(&clients, i) == NULL) {
 			ARRAY_SET(&clients, i, c);
 			return (c);
 		}
 	}
 	ARRAY_ADD(&clients, c);
 	return (c);
 }

 /* Input data from client. */
 void
 server_handle_client(struct client *c)
 {
 	struct window	*w = c->session->curw->window;
 	int		 key, prefix;

 	prefix = options_get_key(&c->session->options, "prefix-key");
 	while (tty_keys_next(&c->tty, &key) == 0) {
 		if (c->flags & CLIENT_PREFIX) {
 			key_bindings_dispatch(key, c);
 			c->flags &= ~CLIENT_PREFIX;
 			continue;
 		} else if (key == prefix)
 			c->flags |= CLIENT_PREFIX;
 		else
 			window_key(w, key);
 	}
 }

 /* Lost a client. */
 void
 server_lost_client(struct client *c)
 {
 	u_int	i;

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

 	tty_free(&c->tty);

 	close(c->fd);
 	buffer_destroy(c->in);
 	buffer_destroy(c->out);
 	xfree(c);

 	recalculate_sizes();
 }

 /* Handle window data. */
 void
 server_handle_window(struct window *w)
 {
 	struct session	*s;
 	u_int		 i;
 	int		 action, update;

 	window_parse(w);

 	if (!(w->flags & WINDOW_BELL) && !(w->flags & WINDOW_ACTIVITY))
 		return;

 	update = 0;
 	for (i = 0; i < ARRAY_LENGTH(&sessions); i++) {
 		s = ARRAY_ITEM(&sessions, i);
 		if (s == NULL || !session_has(s, w))
 			continue;

 		if (w->flags & WINDOW_BELL &&
 		    !session_alert_has_window(s, w, WINDOW_BELL)) {
 			session_alert_add(s, w, WINDOW_BELL);

 			action = options_get_number(&s->options, "bell-action");
 			switch (action) {
 			case BELL_ANY:
 				tty_write_session(s, TTY_CHARACTER, '\007');
 				break;
 			case BELL_CURRENT:
 				if (s->curw->window != w)
 					break;
 				tty_write_session(s, TTY_CHARACTER, '\007');
 				break;
 			}
 			update = 1;
 		}

 		if ((w->flags & WINDOW_MONITOR) &&
 		    (w->flags & WINDOW_ACTIVITY) &&
 		    !session_alert_has_window(s, w, WINDOW_ACTIVITY)) {
 			session_alert_add(s, w, WINDOW_ACTIVITY);
 			update = 1;
 		}
 	}
 	if (update)
 		server_status_window(w);

 	w->flags &= ~(WINDOW_BELL|WINDOW_ACTIVITY);
 }

 /* Lost window: move clients on to next window. */
 void
 server_lost_window(struct window *w)
 {
 	struct client	*c;
 	struct session	*s;
 	struct winlink	*wl;
 	u_int		 i, j;
 	int		 destroyed;

 	log_debug("lost window %d", w->fd);

 	for (i = 0; i < ARRAY_LENGTH(&sessions); i++) {
 		s = ARRAY_ITEM(&sessions, i);
 		if (s == NULL)
 			continue;
 		if (!session_has(s, w))
 			continue;

 	restart:
 		/* Detach window and either redraw or kill clients. */
 		RB_FOREACH(wl, winlinks, &s->windows) {
 			if (wl->window != w)
 				continue;
 			destroyed = session_detach(s, wl);
 			for (j = 0; j < ARRAY_LENGTH(&clients); j++) {
 				c = ARRAY_ITEM(&clients, j);
 				if (c == NULL || c->session != s)
 					continue;
 				if (!destroyed) {
 					server_redraw_client(c);
 					continue;
 				}
 				c->session = NULL;
 				server_write_client(c, MSG_EXIT, NULL, 0);
 			}
 			/* If the session was destroyed, bail now. */
 			if (destroyed)
 				break;
 			goto restart;
 		}
 	}

 	recalculate_sizes();
 }

 void
 server_update_socket(const char *path)
 {
 	struct session	*s;
 	u_int		 i;
 	static int	 last = -1;
 	int		 n;

 	n = 0;
 	for (i = 0; i < ARRAY_LENGTH(&sessions); i++) {
 		s = ARRAY_ITEM(&sessions, i);
 		if (s != NULL && !(s->flags & SESSION_UNATTACHED)) {
 			n++;
 			break;
 		}
 	}

 	if (n != last) {
 		last = n;
 		if (n != 0)
 			chmod(path, S_IRWXU);
 		else
 			chmod(path, S_IRUSR|S_IWUSR);
 	}
 }
	/* $Id: server.c,v 1.67 2008-06-18 19:34:50 nicm Exp $ */

	/*
	* Copyright (c) 2007 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 <sys/ioctl.h>
	#include <sys/socket.h>
	#include <sys/stat.h>
	#include <sys/un.h>

	#include <errno.h>
	#include <fcntl.h>
	#include <poll.h>
	#include <signal.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>
	#include <syslog.h>
	#include <termios.h>
	#include <time.h>
	#include <unistd.h>

	#include "tmux.h"

	/*
	* Main server functions.
	*/

	/* Client list. */
	struct clients clients;

	int server_main(const char *, int);
	void server_fill_windows(struct pollfd **);
	void server_handle_windows(struct pollfd **);
	void server_fill_clients(struct pollfd **);
	void server_handle_clients(struct pollfd **);
	struct client *server_accept_client(int);
	void server_handle_client(struct client *);
	void server_handle_window(struct window *);
	void server_lost_client(struct client *);
	void server_lost_window(struct window *);
	void server_check_redraw(struct client *);
	void server_check_status(struct client *);
	void server_update_socket(const char *);

	/* Fork new server. */
	int
	server_start(const char *path)
	{
	struct sockaddr_un sa;
	size_t size;
	mode_t mask;
	int n, fd, pair[2], mode;
	char *cause;
	u_char ch;

	/* Make a little socketpair to wait for the server to be ready. */
	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pair) != 0)
	fatal("socketpair failed");

	switch (fork()) {
	case -1:
	fatal("fork failed");
	case 0:
	break;
	default:
	close(pair[1]);

	ch = 0x00;
	if (read(pair[0], &ch, 1) == 1 && ch == 0xff) {
	close(pair[0]);
	return (0);
	}
	ch = 0x00;
	if (write(pair[1], &ch, 1) != 1)
	fatal("write failed");
	close(pair[0]);
	return (1);
	}
	close(pair[0]);

	#ifdef DEBUG
	xmalloc_clear();
	#endif

	/*
	* Must daemonise before loading configuration as the PID changes so
	* $TMUX would be wrong for sessions created in the config file.
	*/
	if (daemon(1, 1) != 0)
	fatal("daemon failed");

	ARRAY_INIT(&windows);
	ARRAY_INIT(&clients);
	ARRAY_INIT(&sessions);
	key_bindings_init();

	if (cfg_file != NULL && load_cfg(cfg_file, &cause) != 0) {
	log_warnx("%s", cause);
	exit(1);
	}

	logfile("server");
	#ifndef NO_SETPROCTITLE
	setproctitle("server (%s)", path);
	#endif
	log_debug("server started, pid %ld", (long) getpid());

	memset(&sa, 0, sizeof sa);
	sa.sun_family = AF_UNIX;
	size = strlcpy(sa.sun_path, path, sizeof sa.sun_path);
	if (size >= sizeof sa.sun_path) {
	errno = ENAMETOOLONG;
	fatal("socket failed");
	}
	unlink(sa.sun_path);

	if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1)
	fatal("socket failed");

	mask = umask(S_IXUSR\|S_IRWXG\|S_IRWXO);
	if (bind(fd, (struct sockaddr *) &sa, SUN_LEN(&sa)) == -1)
	fatal("bind failed");
	umask(mask);

	if (listen(fd, 16) == -1)
	fatal("listen failed");

	if ((mode = fcntl(fd, F_GETFL)) == -1)
	fatal("fcntl failed");
	if (fcntl(fd, F_SETFL, mode\|O_NONBLOCK) == -1)
	fatal("fcntl failed");
	if (fcntl(fd, F_SETFD, FD_CLOEXEC) == -1)
	fatal("fcntl failed");

	ch = 0xff;
	if (write(pair[1], &ch, 1) != 1)
	fatal("write failed");
	read(pair[1], &ch, 1); /* Ignore errors; just to wait before closing. */
	close(pair[1]);

	n = server_main(path, fd);
	#ifdef DEBUG
	xmalloc_report(getpid(), "server");
	#endif
	exit(n);
	}

	/* Main server loop. */
	int
	server_main(const char *srv_path, int srv_fd)
	{
	struct pollfd pfds, pfd;
	int nfds;
	u_int i, n;

	siginit();

	pfds = NULL;
	while (!sigterm) {
	/* Initialise pollfd array. */
	nfds = 1 + ARRAY_LENGTH(&windows) + ARRAY_LENGTH(&clients) * 2;
	pfds = xrealloc(pfds, nfds, sizeof *pfds);
	pfd = pfds;

	/* Fill server socket. */
	pfd->fd = srv_fd;
	pfd->events = POLLIN;
	pfd++;

	/* Fill window and client sockets. */
	server_fill_windows(&pfd);
	server_fill_clients(&pfd);

	/* Do the poll. */
	log_debug("polling %d fds", nfds);
	if ((nfds = poll(pfds, nfds, 500)) == -1) {
	if (errno == EAGAIN \|\| errno == EINTR)
	continue;
	fatal("poll failed");
	}
	pfd = pfds;
	log_debug("poll returned %d", nfds);

	/* Handle server socket. */
	if (pfd->revents & (POLLERR\|POLLNVAL\|POLLHUP))
	fatalx("lost server socket");
	if (pfd->revents & POLLIN) {
	server_accept_client(srv_fd);
	continue;
	}
	pfd++;

	/*
	* Handle window and client sockets. Clients can create
	* windows, so windows must come first to avoid messing up by
	* increasing the array size.
	*/
	server_handle_windows(&pfd);
	server_handle_clients(&pfd);

	/* Update socket permissions. */
	server_update_socket(srv_path);

	/*
	* If we have no sessions and clients left, let's get out
	* of here...
	*/
	n = 0;
	for (i = 0; i < ARRAY_LENGTH(&sessions); i++) {
	if (ARRAY_ITEM(&sessions, i) != NULL)
	n++;
	}
	for (i = 0; i < ARRAY_LENGTH(&clients); i++) {
	if (ARRAY_ITEM(&clients, i) != NULL)
	n++;
	}
	if (n == 0)
	break;
	}
	if (pfds != NULL)
	xfree(pfds);

	for (i = 0; i < ARRAY_LENGTH(&sessions); i++) {
	if (ARRAY_ITEM(&sessions, i) != NULL)
	session_destroy(ARRAY_ITEM(&sessions, i));
	}
	ARRAY_FREE(&sessions);

	for (i = 0; i < ARRAY_LENGTH(&clients); i++) {
	if (ARRAY_ITEM(&clients, i) != NULL)
	server_lost_client(ARRAY_ITEM(&clients, i));
	}
	ARRAY_FREE(&clients);

	key_bindings_free();

	close(srv_fd);
	unlink(srv_path);

	return (0);
	}

	/* Fill window pollfds. */
	void
	server_fill_windows(struct pollfd **pfd)
	{
	struct window *w;
	u_int i;

	for (i = 0; i < ARRAY_LENGTH(&windows); i++) {
	if ((w = ARRAY_ITEM(&windows, i)) == NULL)
	(*pfd)->fd = -1;
	else {
	(*pfd)->fd = w->fd;
	(*pfd)->events = POLLIN;
	if (BUFFER_USED(w->out) > 0)
	(*pfd)->events \|= POLLOUT;
	log_debug("adding window %d (%d)", (*pfd)->fd, w->fd);
	}
	(*pfd)++;
	}
	}

	/* Handle window pollfds. */
	void
	server_handle_windows(struct pollfd **pfd)
	{
	struct window *w;
	u_int i;

	for (i = 0; i < ARRAY_LENGTH(&windows); i++) {
	if ((w = ARRAY_ITEM(&windows, i)) != NULL) {
	log_debug("testing window %d (%d)", (*pfd)->fd, w->fd);
	if (buffer_poll(*pfd, w->in, w->out) != 0)
	server_lost_window(w);
	else
	server_handle_window(w);
	}
	(*pfd)++;
	}
	}

	/* Check for general redraw on client. */
	void
	server_check_redraw(struct client *c)
	{
	struct session *s;
	struct screen_redraw_ctx ctx;
	struct screen screen;
	u_int xx, yy, sx, sy;
	char title[BUFSIZ];

	if (c == NULL \|\| c->session == NULL)
	return;
	s = c->session;

	if (options_get_number(&s->options, "set-titles")) {
	xsnprintf(title, sizeof title,
	"%s:%u:%s - \"%s\"", s->name, s->curw->idx,
	s->curw->window->name, s->curw->window->base.title);
	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);
	}
	}

	xx = c->sx;
	yy = c->sy - options_get_number(&s->options, "status-lines");
	if (c->flags & CLIENT_REDRAW) {
	sx = screen_size_x(s->curw->window->screen);
	sy = screen_size_y(s->curw->window->screen);
	if (sx < xx \|\| sy < yy) {
	/*
	* Fake up a blank(ish) screen and use it to draw the
	* empty regions. NOTE: because this uses
	* tty_write_client but doesn't write the client's
	* screen, this can't use anything which relies on
	* cursor position.
	*/
	screen_create(&screen, xx, yy, 0);
	screen_redraw_start(&ctx, &screen, tty_write_client, c);
	if (sx < xx)
	screen_redraw_columns(&ctx, sx, xx - sx);
	if (sy < yy) {
	screen_fill_area(&screen,
	0, sy, xx, 1, '-', 0, 0x70);
	screen_redraw_lines(&ctx, sy, yy - sy);
	}
	screen_redraw_stop(&ctx);
	screen_destroy(&screen);
	}

	screen_redraw_start_client(&ctx, c);
	screen_redraw_lines(&ctx, 0, screen_size_y(ctx.s));
	screen_redraw_stop(&ctx);

	status_redraw(c);
	} else if (c->flags & CLIENT_STATUS)
	status_redraw(c);

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

	/* Check for status line redraw on client. */
	void
	server_check_status(struct client *c)
	{
	struct timespec ts;
	u_int nlines, interval;

	if (c == NULL \|\| c->session == NULL)
	return;

	nlines = options_get_number(&c->session->options, "status-lines");
	interval = options_get_number(&c->session->options, "status-interval");
	if (nlines == 0 \|\| interval == 0)
	return;

	if (clock_gettime(CLOCK_REALTIME, &ts) != 0)
	fatal("clock_gettime");
	ts.tv_sec -= interval;

	if (timespeccmp(&c->status_ts, &ts, <))
	c->flags \|= CLIENT_STATUS;
	}

	/* Fill client pollfds. */
	void
	server_fill_clients(struct pollfd **pfd)
	{
	struct client *c;
	u_int i;

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

	server_check_redraw(c);
	server_check_status(c);

	if (c == NULL)
	(*pfd)->fd = -1;
	else {
	(*pfd)->fd = c->fd;
	(*pfd)->events = POLLIN;
	if (BUFFER_USED(c->out) > 0)
	(*pfd)->events \|= POLLOUT;
	log_debug("adding client %d (%d)", (*pfd)->fd, c->fd);
	}
	(*pfd)++;

	if (c == NULL \|\| c->tty.fd == -1 \|\| c->session == NULL)
	(*pfd)->fd = -1;
	else {
	(*pfd)->fd = c->tty.fd;
	(*pfd)->events = POLLIN;
	if (BUFFER_USED(c->tty.out) > 0)
	(*pfd)->events \|= POLLOUT;
	log_debug("adding tty %d (%d)", (*pfd)->fd, c->tty.fd);
	}
	(*pfd)++;
	}
	}

	/* Handle client pollfds. */
	void
	server_handle_clients(struct pollfd **pfd)
	{
	struct client *c;
	u_int i;

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

	if (c != NULL) {
	log_debug("testing client %d (%d)", (*pfd)->fd, c->fd);
	if (buffer_poll(*pfd, c->in, c->out) != 0) {
	server_lost_client(c);
	(*pfd) += 2;
	continue;
	} else
	server_msg_dispatch(c);
	}
	(*pfd)++;

	if (c != NULL && c->tty.fd != -1 && c->session != NULL) {
	log_debug("testing tty %d (%d)", (*pfd)->fd, c->tty.fd);
	if (buffer_poll(*pfd, c->tty.in, c->tty.out) != 0)
	server_lost_client(c);
	else
	server_handle_client(c);
	}
	(*pfd)++;
	}
	}

	/* accept(2) and create new client. */
	struct client *
	server_accept_client(int srv_fd)
	{
	struct client *c;
	struct sockaddr_storage sa;
	socklen_t slen = sizeof sa;
	int client_fd, mode;
	u_int i;

	client_fd = accept(srv_fd, (struct sockaddr *) &sa, &slen);
	if (client_fd == -1) {
	if (errno == EAGAIN \|\| errno == EINTR \|\| errno == ECONNABORTED)
	return (NULL);
	fatal("accept failed");
	}
	if ((mode = fcntl(client_fd, F_GETFL)) == -1)
	fatal("fcntl failed");
	if (fcntl(client_fd, F_SETFL, mode\|O_NONBLOCK) == -1)
	fatal("fcntl failed");

	c = xcalloc(1, sizeof *c);
	c->fd = client_fd;
	c->in = buffer_create(BUFSIZ);
	c->out = buffer_create(BUFSIZ);

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

	c->session = NULL;
	c->sx = 80;
	c->sy = 25;

	for (i = 0; i < ARRAY_LENGTH(&clients); i++) {
	if (ARRAY_ITEM(&clients, i) == NULL) {
	ARRAY_SET(&clients, i, c);
	return (c);
	}
	}
	ARRAY_ADD(&clients, c);
	return (c);
	}

	/* Input data from client. */
	void
	server_handle_client(struct client *c)
	{
	struct window *w = c->session->curw->window;
	int key, prefix;

	prefix = options_get_key(&c->session->options, "prefix-key");
	while (tty_keys_next(&c->tty, &key) == 0) {
	if (c->flags & CLIENT_PREFIX) {
	key_bindings_dispatch(key, c);
	c->flags &= ~CLIENT_PREFIX;
	continue;
	} else if (key == prefix)
	c->flags \|= CLIENT_PREFIX;
	else
	window_key(w, key);
	}
	}

	/* Lost a client. */
	void
	server_lost_client(struct client *c)
	{
	u_int i;

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

	tty_free(&c->tty);

	close(c->fd);
	buffer_destroy(c->in);
	buffer_destroy(c->out);
	xfree(c);

	recalculate_sizes();
	}

	/* Handle window data. */
	void
	server_handle_window(struct window *w)
	{
	struct session *s;
	u_int i;
	int action, update;

	window_parse(w);

	if (!(w->flags & WINDOW_BELL) && !(w->flags & WINDOW_ACTIVITY))
	return;

	update = 0;
	for (i = 0; i < ARRAY_LENGTH(&sessions); i++) {
	s = ARRAY_ITEM(&sessions, i);
	if (s == NULL \|\| !session_has(s, w))
	continue;

	if (w->flags & WINDOW_BELL &&
	!session_alert_has_window(s, w, WINDOW_BELL)) {
	session_alert_add(s, w, WINDOW_BELL);

	action = options_get_number(&s->options, "bell-action");
	switch (action) {
	case BELL_ANY:
	tty_write_session(s, TTY_CHARACTER, '\007');
	break;
	case BELL_CURRENT:
	if (s->curw->window != w)
	break;
	tty_write_session(s, TTY_CHARACTER, '\007');
	break;
	}
	update = 1;
	}

	if ((w->flags & WINDOW_MONITOR) &&
	(w->flags & WINDOW_ACTIVITY) &&
	!session_alert_has_window(s, w, WINDOW_ACTIVITY)) {
	session_alert_add(s, w, WINDOW_ACTIVITY);
	update = 1;
	}
	}
	if (update)
	server_status_window(w);

	w->flags &= ~(WINDOW_BELL\|WINDOW_ACTIVITY);
	}

	/* Lost window: move clients on to next window. */
	void
	server_lost_window(struct window *w)
	{
	struct client *c;
	struct session *s;
	struct winlink *wl;
	u_int i, j;
	int destroyed;

	log_debug("lost window %d", w->fd);

	for (i = 0; i < ARRAY_LENGTH(&sessions); i++) {
	s = ARRAY_ITEM(&sessions, i);
	if (s == NULL)
	continue;
	if (!session_has(s, w))
	continue;

	restart:
	/* Detach window and either redraw or kill clients. */
	RB_FOREACH(wl, winlinks, &s->windows) {
	if (wl->window != w)
	continue;
	destroyed = session_detach(s, wl);
	for (j = 0; j < ARRAY_LENGTH(&clients); j++) {
	c = ARRAY_ITEM(&clients, j);
	if (c == NULL \|\| c->session != s)
	continue;
	if (!destroyed) {
	server_redraw_client(c);
	continue;
	}
	c->session = NULL;
	server_write_client(c, MSG_EXIT, NULL, 0);
	}
	/* If the session was destroyed, bail now. */
	if (destroyed)
	break;
	goto restart;
	}
	}

	recalculate_sizes();
	}

	void
	server_update_socket(const char *path)
	{
	struct session *s;
	u_int i;
	static int last = -1;
	int n;

	n = 0;
	for (i = 0; i < ARRAY_LENGTH(&sessions); i++) {
	s = ARRAY_ITEM(&sessions, i);
	if (s != NULL && !(s->flags & SESSION_UNATTACHED)) {
	n++;
	break;
	}
	}

	if (n != last) {
	last = n;
	if (n != 0)
	chmod(path, S_IRWXU);
	else
	chmod(path, S_IRUSR\|S_IWUSR);
	}
	}