server.c - tmux - Rivoreo Source Code Repositories

 /* $OpenBSD$ */

 /*
  * 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 <sys/wait.h>

 #include <errno.h>
 #include <event.h>
 #include <fcntl.h>
 #include <paths.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;
 struct clients	 dead_clients;

 int		 server_fd;
 int		 server_shutdown;
 struct event	 server_ev_accept;
 struct event	 server_ev_sigterm;
 struct event	 server_ev_sigusr1;
 struct event	 server_ev_sigchld;
 struct event	 server_ev_second;

 int		 server_create_socket(void);
 void		 server_loop(void);
 int		 server_should_shutdown(void);
 void		 server_send_shutdown(void);
 void		 server_clean_dead(void);
 void		 server_accept_callback(int, short, void *);
 void		 server_signal_callback(int, short, void *);
 void		 server_child_signal(void);
 void		 server_child_exited(pid_t, int);
 void		 server_child_stopped(pid_t, int);
 void		 server_second_callback(int, short, void *);
 void		 server_lock_server(void);
 void		 server_lock_sessions(void);

 /* Create server socket. */
 int
 server_create_socket(void)
 {
 	struct sockaddr_un	sa;
 	size_t			size;
 	mode_t			mask;
 	int			fd, mode;

 	memset(&sa, 0, sizeof sa);
 	sa.sun_family = AF_UNIX;
 	size = strlcpy(sa.sun_path, socket_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");

 	server_update_socket();

 	return (fd);
 }

 /* Fork new server. */
 int
 server_start(char *path)
 {
 	struct client	*c;
 	int		 pair[2];
 	char		*cause, rpathbuf[MAXPATHLEN];
 	struct timeval	 tv;

 	/* The first client is special and gets a socketpair; create it. */
 	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]);
 		return (pair[0]);
 	}
 	close(pair[0]);

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

 	logfile("server");
 	log_debug("server started, pid %ld", (long) getpid());

 	ARRAY_INIT(&windows);
 	ARRAY_INIT(&clients);
 	ARRAY_INIT(&dead_clients);
 	ARRAY_INIT(&sessions);
 	ARRAY_INIT(&dead_sessions);
 	TAILQ_INIT(&session_groups);
 	mode_key_init_trees();
 	key_bindings_init();
 	utf8_build();

 	start_time = time(NULL);
 	socket_path = path;

 	if (realpath(socket_path, rpathbuf) == NULL)
 		strlcpy(rpathbuf, socket_path, sizeof rpathbuf);
 	log_debug("socket path %s", socket_path);
 	setproctitle("server (%s)", rpathbuf);

 	event_init();

 	server_fd = server_create_socket();
 	server_client_create(pair[1]);

 	if (access(SYSTEM_CFG, R_OK) == 0) {
 		if (load_cfg(SYSTEM_CFG, NULL, &cause) != 0)
 			goto error;
 	} else if (errno != ENOENT) {
 		xasprintf(&cause, "%s: %s", strerror(errno), SYSTEM_CFG);
 		goto error;
 	}
 	if (cfg_file != NULL && load_cfg(cfg_file, NULL, &cause) != 0)
 		goto error;

 	event_set(&server_ev_accept,
 	    server_fd, EV_READ|EV_PERSIST, server_accept_callback, NULL);
 	event_add(&server_ev_accept, NULL);

 	memset(&tv, 0, sizeof tv);
 	tv.tv_sec = 1;
 	evtimer_set(&server_ev_second, server_second_callback, NULL);
 	evtimer_add(&server_ev_second, &tv);

 	server_signal_set();
 	server_loop();
 	exit(0);

 error:
 	/* Write the error and shutdown the server. */
 	c = ARRAY_FIRST(&clients);

 	server_write_error(c, cause);
 	server_write_client(c, MSG_EXIT, NULL, 0);
 	xfree(cause);

 	server_shutdown = 1;

 	server_signal_set();
 	server_loop();
 	exit(1);
 }

 /* Main server loop. */
 void
 server_loop(void)
 {
 	while (!server_should_shutdown()) {
 		event_loop(EVLOOP_ONCE);

 		server_window_loop();
 		server_client_loop();

 		key_bindings_clean();
 		server_clean_dead();
 	}
 }

 /* Check if the server should be shutting down (no more clients or windows). */
 int
 server_should_shutdown(void)
 {
 	u_int	i;

 	for (i = 0; i < ARRAY_LENGTH(&sessions); i++) {
 		if (ARRAY_ITEM(&sessions, i) != NULL)
 			return (0);
 	}
 	for (i = 0; i < ARRAY_LENGTH(&clients); i++) {
 		if (ARRAY_ITEM(&clients, i) != NULL)
 			return (0);
 	}
 	return (1);
 }

 /* Shutdown the server by killing all clients and windows. */
 void
 server_send_shutdown(void)
 {
 	struct client	*c;
 	struct session	*s;
 	u_int		 i;

 	for (i = 0; i < ARRAY_LENGTH(&clients); i++) {
 		c = ARRAY_ITEM(&clients, i);
 		if (c != NULL) {
 			if (c->flags & (CLIENT_BAD|CLIENT_SUSPENDED))
 				server_client_lost(c);
 			else
 				server_write_client(c, MSG_SHUTDOWN, NULL, 0);
 			c->session = NULL;
 		}
 	}

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

 /* Free dead, unreferenced clients and sessions. */
 void
 server_clean_dead(void)
 {
 	struct session	*s;
 	struct client	*c;
 	u_int		 i;

 	for (i = 0; i < ARRAY_LENGTH(&dead_sessions); i++) {
 		s = ARRAY_ITEM(&dead_sessions, i);
 		if (s == NULL || s->references != 0)
 			continue;
 		ARRAY_SET(&dead_sessions, i, NULL);
 		xfree(s);
 	}

 	for (i = 0; i < ARRAY_LENGTH(&dead_clients); i++) {
 		c = ARRAY_ITEM(&dead_clients, i);
 		if (c == NULL || c->references != 0)
 			continue;
 		ARRAY_SET(&dead_clients, i, NULL);
 		xfree(c);
 	}
 }

 /* Update socket execute permissions based on whether sessions are attached. */
 void
 server_update_socket(void)
 {
 	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(socket_path, S_IRWXU);
 		else
 			chmod(socket_path, S_IRUSR|S_IWUSR);
 	}
 }

 /* Callback for server socket. */
 /* ARGSUSED */
 void
 server_accept_callback(int fd, short events, unused void *data)
 {
 	struct sockaddr_storage	sa;
 	socklen_t		slen = sizeof sa;
 	int			newfd;

 	if (!(events & EV_READ))
 		return;

 	newfd = accept(fd, (struct sockaddr *) &sa, &slen);
 	if (newfd == -1) {
 		if (errno == EAGAIN || errno == EINTR || errno == ECONNABORTED)
 			return;
 		fatal("accept failed");
 	}
 	if (server_shutdown) {
 		close(newfd);
 		return;
 	}
 	server_client_create(newfd);
 }

 /* Set up server signal handling. */
 void
 server_signal_set(void)
 {
 	struct sigaction	 sigact;

 	memset(&sigact, 0, sizeof sigact);
 	sigemptyset(&sigact.sa_mask);
 	sigact.sa_flags = SA_RESTART;
 	sigact.sa_handler = SIG_IGN;
 	if (sigaction(SIGINT, &sigact, NULL) != 0)
 		fatal("sigaction failed");
 	if (sigaction(SIGPIPE, &sigact, NULL) != 0)
 		fatal("sigaction failed");
 	if (sigaction(SIGUSR2, &sigact, NULL) != 0)
 		fatal("sigaction failed");
 	if (sigaction(SIGTSTP, &sigact, NULL) != 0)
 		fatal("sigaction failed");

 	signal_set(&server_ev_sigchld, SIGCHLD, server_signal_callback, NULL);
 	signal_add(&server_ev_sigchld, NULL);
 	signal_set(&server_ev_sigterm, SIGTERM, server_signal_callback, NULL);
 	signal_add(&server_ev_sigterm, NULL);
 	signal_set(&server_ev_sigusr1, SIGUSR1, server_signal_callback, NULL);
 	signal_add(&server_ev_sigusr1, NULL);
 }

 /* Destroy server signal events. */
 void
 server_signal_clear(void)
 {
 	struct sigaction	 sigact;

 	memset(&sigact, 0, sizeof sigact);
 	sigemptyset(&sigact.sa_mask);
 	sigact.sa_flags = SA_RESTART;
 	sigact.sa_handler = SIG_DFL;
 	if (sigaction(SIGINT, &sigact, NULL) != 0)
 		fatal("sigaction failed");
 	if (sigaction(SIGPIPE, &sigact, NULL) != 0)
 		fatal("sigaction failed");
 	if (sigaction(SIGUSR2, &sigact, NULL) != 0)
 		fatal("sigaction failed");
 	if (sigaction(SIGTSTP, &sigact, NULL) != 0)
 		fatal("sigaction failed");

 	signal_del(&server_ev_sigchld);
 	signal_del(&server_ev_sigterm);
 	signal_del(&server_ev_sigusr1);
 }

 /* Signal handler. */
 /* ARGSUSED */
 void
 server_signal_callback(int sig, unused short events, unused void *data)
 {
 	switch (sig) {
 	case SIGTERM:
 		server_shutdown = 1;
 		server_send_shutdown();
 		break;
 	case SIGCHLD:
 		server_child_signal();
 		break;
 	case SIGUSR1:
 		event_del(&server_ev_accept);
 		close(server_fd);
 		server_fd = server_create_socket();
 		event_set(&server_ev_accept, server_fd,
 		    EV_READ|EV_PERSIST, server_accept_callback, NULL);
 		event_add(&server_ev_accept, NULL);
 		break;
 	}
 }

 /* Handle SIGCHLD. */
 void
 server_child_signal(void)
 {
 	int	 status;
 	pid_t	 pid;

 	for (;;) {
 		switch (pid = waitpid(WAIT_ANY, &status, WNOHANG|WUNTRACED)) {
 		case -1:
 			if (errno == ECHILD)
 				return;
 			fatal("waitpid failed");
 		case 0:
 			return;
 		}
 		if (WIFSTOPPED(status))
 			server_child_stopped(pid, status);
 		else if (WIFEXITED(status))
 			server_child_exited(pid, status);
 	}
 }

 /* Handle exited children. */
 void
 server_child_exited(pid_t pid, int status)
 {
 	struct window		*w;
 	struct window_pane	*wp;
 	struct job		*job;
 	u_int		 	 i;

 	for (i = 0; i < ARRAY_LENGTH(&windows); i++) {
 		if ((w = ARRAY_ITEM(&windows, i)) == NULL)
 			continue;
 		TAILQ_FOREACH(wp, &w->panes, entry) {
 			if (wp->pid == pid) {
 				server_destroy_pane(wp);
 				break;
 			}
 		}
 	}

 	SLIST_FOREACH(job, &all_jobs, lentry) {
 		if (pid == job->pid) {
 			job_died(job, status);	/* might free job */
 			break;
 		}
 	}
 }

 /* Handle stopped children. */
 void
 server_child_stopped(pid_t pid, int status)
 {
 	struct window		*w;
 	struct window_pane	*wp;
 	u_int			 i;

 	if (WSTOPSIG(status) == SIGTTIN || WSTOPSIG(status) == SIGTTOU)
 		return;

 	for (i = 0; i < ARRAY_LENGTH(&windows); i++) {
 		if ((w = ARRAY_ITEM(&windows, i)) == NULL)
 			continue;
 		TAILQ_FOREACH(wp, &w->panes, entry) {
 			if (wp->pid == pid) {
 				if (killpg(pid, SIGCONT) != 0)
 					kill(pid, SIGCONT);
 			}
 		}
 	}
 }

 /* Handle once-per-second timer events. */
 /* ARGSUSED */
 void
 server_second_callback(unused int fd, unused short events, unused void *arg)
 {
 	struct window		*w;
 	struct window_pane	*wp;
 	struct timeval		 tv;
 	u_int		 	 i;

 	if (options_get_number(&global_s_options, "lock-server"))
 		server_lock_server();
 	else
 		server_lock_sessions();

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

 		TAILQ_FOREACH(wp, &w->panes, entry) {
 			if (wp->mode != NULL && wp->mode->timer != NULL)
 				wp->mode->timer(wp);
 		}
 	}

 	server_client_status_timer();

 	evtimer_del(&server_ev_second);
 	memset(&tv, 0, sizeof tv);
 	tv.tv_sec = 1;
 	evtimer_add(&server_ev_second, &tv);
 }

 /* Lock the server if ALL sessions have hit the time limit. */
 void
 server_lock_server(void)
 {
 	struct session  *s;
 	u_int            i;
 	int		 timeout;
 	time_t           t;

 	t = time(NULL);
 	for (i = 0; i < ARRAY_LENGTH(&sessions); i++) {
 		if ((s = ARRAY_ITEM(&sessions, i)) == NULL)
 			continue;

 		if (s->flags & SESSION_UNATTACHED) {
 			if (gettimeofday(&s->activity_time, NULL) != 0)
 				fatal("gettimeofday failed");
 			continue;
 		}

 		timeout = options_get_number(&s->options, "lock-after-time");
 		if (timeout <= 0 || t <= s->activity_time.tv_sec + timeout)
 			return;	/* not timed out */
 	}

 	server_lock();
 	recalculate_sizes();
 }

 /* Lock any sessions which have timed out. */
 void
 server_lock_sessions(void)
 {
         struct session  *s;
 	u_int		 i;
 	int		 timeout;
 	time_t		 t;

 	t = time(NULL);
 	for (i = 0; i < ARRAY_LENGTH(&sessions); i++) {
 		if ((s = ARRAY_ITEM(&sessions, i)) == NULL)
 			continue;

 		if (s->flags & SESSION_UNATTACHED) {
 			if (gettimeofday(&s->activity_time, NULL) != 0)
 				fatal("gettimeofday failed");
 			continue;
 		}

 		timeout = options_get_number(&s->options, "lock-after-time");
 		if (timeout > 0 && t > s->activity_time.tv_sec + timeout) {
 			server_lock_session(s);
 			recalculate_sizes();
 		}
 	}
 }
	/* $OpenBSD$ */

	/*
	* 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 <sys/wait.h>

	#include <errno.h>
	#include <event.h>
	#include <fcntl.h>
	#include <paths.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;
	struct clients dead_clients;

	int server_fd;
	int server_shutdown;
	struct event server_ev_accept;
	struct event server_ev_sigterm;
	struct event server_ev_sigusr1;
	struct event server_ev_sigchld;
	struct event server_ev_second;

	int server_create_socket(void);
	void server_loop(void);
	int server_should_shutdown(void);
	void server_send_shutdown(void);
	void server_clean_dead(void);
	void server_accept_callback(int, short, void *);
	void server_signal_callback(int, short, void *);
	void server_child_signal(void);
	void server_child_exited(pid_t, int);
	void server_child_stopped(pid_t, int);
	void server_second_callback(int, short, void *);
	void server_lock_server(void);
	void server_lock_sessions(void);

	/* Create server socket. */
	int
	server_create_socket(void)
	{
	struct sockaddr_un sa;
	size_t size;
	mode_t mask;
	int fd, mode;

	memset(&sa, 0, sizeof sa);
	sa.sun_family = AF_UNIX;
	size = strlcpy(sa.sun_path, socket_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");

	server_update_socket();

	return (fd);
	}

	/* Fork new server. */
	int
	server_start(char *path)
	{
	struct client *c;
	int pair[2];
	char *cause, rpathbuf[MAXPATHLEN];
	struct timeval tv;

	/* The first client is special and gets a socketpair; create it. */
	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]);
	return (pair[0]);
	}
	close(pair[0]);

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

	logfile("server");
	log_debug("server started, pid %ld", (long) getpid());

	ARRAY_INIT(&windows);
	ARRAY_INIT(&clients);
	ARRAY_INIT(&dead_clients);
	ARRAY_INIT(&sessions);
	ARRAY_INIT(&dead_sessions);
	TAILQ_INIT(&session_groups);
	mode_key_init_trees();
	key_bindings_init();
	utf8_build();

	start_time = time(NULL);
	socket_path = path;

	if (realpath(socket_path, rpathbuf) == NULL)
	strlcpy(rpathbuf, socket_path, sizeof rpathbuf);
	log_debug("socket path %s", socket_path);
	setproctitle("server (%s)", rpathbuf);

	event_init();

	server_fd = server_create_socket();
	server_client_create(pair[1]);

	if (access(SYSTEM_CFG, R_OK) == 0) {
	if (load_cfg(SYSTEM_CFG, NULL, &cause) != 0)
	goto error;
	} else if (errno != ENOENT) {
	xasprintf(&cause, "%s: %s", strerror(errno), SYSTEM_CFG);
	goto error;
	}
	if (cfg_file != NULL && load_cfg(cfg_file, NULL, &cause) != 0)
	goto error;

	event_set(&server_ev_accept,
	server_fd, EV_READ\|EV_PERSIST, server_accept_callback, NULL);
	event_add(&server_ev_accept, NULL);

	memset(&tv, 0, sizeof tv);
	tv.tv_sec = 1;
	evtimer_set(&server_ev_second, server_second_callback, NULL);
	evtimer_add(&server_ev_second, &tv);

	server_signal_set();
	server_loop();
	exit(0);

	error:
	/* Write the error and shutdown the server. */
	c = ARRAY_FIRST(&clients);

	server_write_error(c, cause);
	server_write_client(c, MSG_EXIT, NULL, 0);
	xfree(cause);

	server_shutdown = 1;

	server_signal_set();
	server_loop();
	exit(1);
	}

	/* Main server loop. */
	void
	server_loop(void)
	{
	while (!server_should_shutdown()) {
	event_loop(EVLOOP_ONCE);

	server_window_loop();
	server_client_loop();

	key_bindings_clean();
	server_clean_dead();
	}
	}

	/* Check if the server should be shutting down (no more clients or windows). */
	int
	server_should_shutdown(void)
	{
	u_int i;

	for (i = 0; i < ARRAY_LENGTH(&sessions); i++) {
	if (ARRAY_ITEM(&sessions, i) != NULL)
	return (0);
	}
	for (i = 0; i < ARRAY_LENGTH(&clients); i++) {
	if (ARRAY_ITEM(&clients, i) != NULL)
	return (0);
	}
	return (1);
	}

	/* Shutdown the server by killing all clients and windows. */
	void
	server_send_shutdown(void)
	{
	struct client *c;
	struct session *s;
	u_int i;

	for (i = 0; i < ARRAY_LENGTH(&clients); i++) {
	c = ARRAY_ITEM(&clients, i);
	if (c != NULL) {
	if (c->flags & (CLIENT_BAD\|CLIENT_SUSPENDED))
	server_client_lost(c);
	else
	server_write_client(c, MSG_SHUTDOWN, NULL, 0);
	c->session = NULL;
	}
	}

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

	/* Free dead, unreferenced clients and sessions. */
	void
	server_clean_dead(void)
	{
	struct session *s;
	struct client *c;
	u_int i;

	for (i = 0; i < ARRAY_LENGTH(&dead_sessions); i++) {
	s = ARRAY_ITEM(&dead_sessions, i);
	if (s == NULL \|\| s->references != 0)
	continue;
	ARRAY_SET(&dead_sessions, i, NULL);
	xfree(s);
	}

	for (i = 0; i < ARRAY_LENGTH(&dead_clients); i++) {
	c = ARRAY_ITEM(&dead_clients, i);
	if (c == NULL \|\| c->references != 0)
	continue;
	ARRAY_SET(&dead_clients, i, NULL);
	xfree(c);
	}
	}

	/* Update socket execute permissions based on whether sessions are attached. */
	void
	server_update_socket(void)
	{
	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(socket_path, S_IRWXU);
	else
	chmod(socket_path, S_IRUSR\|S_IWUSR);
	}
	}

	/* Callback for server socket. */
	/* ARGSUSED */
	void
	server_accept_callback(int fd, short events, unused void *data)
	{
	struct sockaddr_storage sa;
	socklen_t slen = sizeof sa;
	int newfd;

	if (!(events & EV_READ))
	return;

	newfd = accept(fd, (struct sockaddr *) &sa, &slen);
	if (newfd == -1) {
	if (errno == EAGAIN \|\| errno == EINTR \|\| errno == ECONNABORTED)
	return;
	fatal("accept failed");
	}
	if (server_shutdown) {
	close(newfd);
	return;
	}
	server_client_create(newfd);
	}

	/* Set up server signal handling. */
	void
	server_signal_set(void)
	{
	struct sigaction sigact;

	memset(&sigact, 0, sizeof sigact);
	sigemptyset(&sigact.sa_mask);
	sigact.sa_flags = SA_RESTART;
	sigact.sa_handler = SIG_IGN;
	if (sigaction(SIGINT, &sigact, NULL) != 0)
	fatal("sigaction failed");
	if (sigaction(SIGPIPE, &sigact, NULL) != 0)
	fatal("sigaction failed");
	if (sigaction(SIGUSR2, &sigact, NULL) != 0)
	fatal("sigaction failed");
	if (sigaction(SIGTSTP, &sigact, NULL) != 0)
	fatal("sigaction failed");

	signal_set(&server_ev_sigchld, SIGCHLD, server_signal_callback, NULL);
	signal_add(&server_ev_sigchld, NULL);
	signal_set(&server_ev_sigterm, SIGTERM, server_signal_callback, NULL);
	signal_add(&server_ev_sigterm, NULL);
	signal_set(&server_ev_sigusr1, SIGUSR1, server_signal_callback, NULL);
	signal_add(&server_ev_sigusr1, NULL);
	}

	/* Destroy server signal events. */
	void
	server_signal_clear(void)
	{
	struct sigaction sigact;

	memset(&sigact, 0, sizeof sigact);
	sigemptyset(&sigact.sa_mask);
	sigact.sa_flags = SA_RESTART;
	sigact.sa_handler = SIG_DFL;
	if (sigaction(SIGINT, &sigact, NULL) != 0)
	fatal("sigaction failed");
	if (sigaction(SIGPIPE, &sigact, NULL) != 0)
	fatal("sigaction failed");
	if (sigaction(SIGUSR2, &sigact, NULL) != 0)
	fatal("sigaction failed");
	if (sigaction(SIGTSTP, &sigact, NULL) != 0)
	fatal("sigaction failed");

	signal_del(&server_ev_sigchld);
	signal_del(&server_ev_sigterm);
	signal_del(&server_ev_sigusr1);
	}

	/* Signal handler. */
	/* ARGSUSED */
	void
	server_signal_callback(int sig, unused short events, unused void *data)
	{
	switch (sig) {
	case SIGTERM:
	server_shutdown = 1;
	server_send_shutdown();
	break;
	case SIGCHLD:
	server_child_signal();
	break;
	case SIGUSR1:
	event_del(&server_ev_accept);
	close(server_fd);
	server_fd = server_create_socket();
	event_set(&server_ev_accept, server_fd,
	EV_READ\|EV_PERSIST, server_accept_callback, NULL);
	event_add(&server_ev_accept, NULL);
	break;
	}
	}

	/* Handle SIGCHLD. */
	void
	server_child_signal(void)
	{
	int status;
	pid_t pid;

	for (;;) {
	switch (pid = waitpid(WAIT_ANY, &status, WNOHANG\|WUNTRACED)) {
	case -1:
	if (errno == ECHILD)
	return;
	fatal("waitpid failed");
	case 0:
	return;
	}
	if (WIFSTOPPED(status))
	server_child_stopped(pid, status);
	else if (WIFEXITED(status))
	server_child_exited(pid, status);
	}
	}

	/* Handle exited children. */
	void
	server_child_exited(pid_t pid, int status)
	{
	struct window *w;
	struct window_pane *wp;
	struct job *job;
	u_int i;

	for (i = 0; i < ARRAY_LENGTH(&windows); i++) {
	if ((w = ARRAY_ITEM(&windows, i)) == NULL)
	continue;
	TAILQ_FOREACH(wp, &w->panes, entry) {
	if (wp->pid == pid) {
	server_destroy_pane(wp);
	break;
	}
	}
	}

	SLIST_FOREACH(job, &all_jobs, lentry) {
	if (pid == job->pid) {
	job_died(job, status); /* might free job */
	break;
	}
	}
	}

	/* Handle stopped children. */
	void
	server_child_stopped(pid_t pid, int status)
	{
	struct window *w;
	struct window_pane *wp;
	u_int i;

	if (WSTOPSIG(status) == SIGTTIN \|\| WSTOPSIG(status) == SIGTTOU)
	return;

	for (i = 0; i < ARRAY_LENGTH(&windows); i++) {
	if ((w = ARRAY_ITEM(&windows, i)) == NULL)
	continue;
	TAILQ_FOREACH(wp, &w->panes, entry) {
	if (wp->pid == pid) {
	if (killpg(pid, SIGCONT) != 0)
	kill(pid, SIGCONT);
	}
	}
	}
	}

	/* Handle once-per-second timer events. */
	/* ARGSUSED */
	void
	server_second_callback(unused int fd, unused short events, unused void *arg)
	{
	struct window *w;
	struct window_pane *wp;
	struct timeval tv;
	u_int i;

	if (options_get_number(&global_s_options, "lock-server"))
	server_lock_server();
	else
	server_lock_sessions();

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

	TAILQ_FOREACH(wp, &w->panes, entry) {
	if (wp->mode != NULL && wp->mode->timer != NULL)
	wp->mode->timer(wp);
	}
	}

	server_client_status_timer();

	evtimer_del(&server_ev_second);
	memset(&tv, 0, sizeof tv);
	tv.tv_sec = 1;
	evtimer_add(&server_ev_second, &tv);
	}

	/* Lock the server if ALL sessions have hit the time limit. */
	void
	server_lock_server(void)
	{
	struct session *s;
	u_int i;
	int timeout;
	time_t t;

	t = time(NULL);
	for (i = 0; i < ARRAY_LENGTH(&sessions); i++) {
	if ((s = ARRAY_ITEM(&sessions, i)) == NULL)
	continue;

	if (s->flags & SESSION_UNATTACHED) {
	if (gettimeofday(&s->activity_time, NULL) != 0)
	fatal("gettimeofday failed");
	continue;
	}

	timeout = options_get_number(&s->options, "lock-after-time");
	if (timeout <= 0 \|\| t <= s->activity_time.tv_sec + timeout)
	return; /* not timed out */
	}

	server_lock();
	recalculate_sizes();
	}

	/* Lock any sessions which have timed out. */
	void
	server_lock_sessions(void)
	{
	struct session *s;
	u_int i;
	int timeout;
	time_t t;

	t = time(NULL);
	for (i = 0; i < ARRAY_LENGTH(&sessions); i++) {
	if ((s = ARRAY_ITEM(&sessions, i)) == NULL)
	continue;

	if (s->flags & SESSION_UNATTACHED) {
	if (gettimeofday(&s->activity_time, NULL) != 0)
	fatal("gettimeofday failed");
	continue;
	}

	timeout = options_get_number(&s->options, "lock-after-time");
	if (timeout > 0 && t > s->activity_time.tv_sec + timeout) {
	server_lock_session(s);
	recalculate_sizes();
	}
	}
	}