Initial changes to move tmux to libevent.

This moves the client-side loops are pretty much fully over to event-based only
(tmux.c and client.c) but server-side (server.c and friends) treats libevent as
a sort of clever poll, waking up after every event to run various things.

Moving the server stuff over to bufferevents and timers and so on will come
later.

server.c

@@ -24,6 +24,7 @@
 #include <sys/wait.h>
 
 #include <errno.h>
+#include <event.h>
 #include <fcntl.h>
 #include <paths.h>
 #include <signal.h>
@@ -45,112 +46,28 @@
 struct clients	 clients;
 struct clients	 dead_clients;
 
-/* Mapping of a pollfd to an fd independent of its position in the array. */
-struct poll_item {
-	int	 fd;
-	int	 events;
-
-	void	 (*fn)(int, int, void *);
-	void	*data;
-
-	RB_ENTRY(poll_item) entry;
-};
-RB_HEAD(poll_items, poll_item) poll_items;
-
-int		 server_poll_cmp(struct poll_item *, struct poll_item *);
-struct poll_item*server_poll_lookup(int);
-struct pollfd	*server_poll_flatten(int *);
-void		 server_poll_dispatch(struct pollfd *, int);
-void		 server_poll_reset(void);
-RB_PROTOTYPE(poll_items, poll_item, entry, server_poll_cmp);
-RB_GENERATE(poll_items, poll_item, entry, server_poll_cmp);
+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_callback(int, int, void *);
-int		 server_main(int);
-void		 server_shutdown(void);
+void		 server_loop(void);
 int		 server_should_shutdown(void);
-void		 server_child_signal(void);
+void		 server_send_shutdown(void);
 void		 server_clean_dead(void);
-void		 server_second_timers(void);
+int		 server_update_socket(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);
-int		 server_update_socket(void);
-
-int
-server_poll_cmp(struct poll_item *pitem1, struct poll_item *pitem2)
-{
-	return (pitem1->fd - pitem2->fd);
-}
-
-void
-server_poll_add(int fd, int events, void (*fn)(int, int, void *), void *data)
-{
-	struct poll_item	*pitem;
-
-	pitem = xmalloc(sizeof *pitem);
-	pitem->fd = fd;
-	pitem->events = events;
-
-	pitem->fn = fn;
-	pitem->data = data;
-
-	RB_INSERT(poll_items, &poll_items, pitem);
-}
-
-struct poll_item *
-server_poll_lookup(int fd)
-{
-	struct poll_item	pitem;
-
-	pitem.fd = fd;
-	return (RB_FIND(poll_items, &poll_items, &pitem));
-}
-
-struct pollfd *
-server_poll_flatten(int *nfds)
-{
-	struct poll_item	*pitem;
-	struct pollfd		*pfds;
-
-	pfds = NULL;
-	*nfds = 0;
-	RB_FOREACH(pitem, poll_items, &poll_items) {
-		pfds = xrealloc(pfds, (*nfds) + 1, sizeof *pfds);
-		pfds[*nfds].fd = pitem->fd;
-		pfds[*nfds].events = pitem->events;
-		(*nfds)++;
-	}
-	return (pfds);
-}
-
-void
-server_poll_dispatch(struct pollfd *pfds, int nfds)
-{
-	struct poll_item	*pitem;
-	struct pollfd		*pfd;
-
-	while (nfds > 0) {
-		pfd = &pfds[--nfds];
-		if (pfd->revents != 0) {
-			pitem = server_poll_lookup(pfd->fd);
-			pitem->fn(pitem->fd, pfd->revents, pitem->data);
-		}
-	}
-	xfree(pfds);
-}
-
-void
-server_poll_reset(void)
-{
-	struct poll_item	*pitem;
-
-	while (!RB_EMPTY(&poll_items)) {
-		pitem = RB_ROOT(&poll_items);
-		RB_REMOVE(poll_items, &poll_items, pitem);
-		xfree(pitem);
-	}
-}
 
 /* Create server socket. */
 int
@@ -191,40 +108,14 @@ server_create_socket(void)
 	return (fd);
 }
 
-/* Callback for server socket. */
-void
-server_callback(int fd, int events, unused void *data)
-{
-	struct sockaddr_storage	sa;
-	socklen_t		slen = sizeof sa;
-	int			newfd;
-
-	if (events & (POLLERR|POLLNVAL|POLLHUP))
-		fatalx("lost server socket");
-	if (!(events & POLLIN))
-		return;
-
-	newfd = accept(fd, (struct sockaddr *) &sa, &slen);
-	if (newfd == -1) {
-		if (errno == EAGAIN || errno == EINTR || errno == ECONNABORTED)
-			return;
-		fatal("accept failed");
-	}
-	if (sigterm) {
-		close(newfd);
-		return;
-	}
-	server_client_create(newfd);
-}
-
 /* Fork new server. */
 int
 server_start(char *path)
 {
 	struct client	*c;
-	int		 pair[2], srv_fd;
-	char		*cause;
-	char		 rpathbuf[MAXPATHLEN];
+	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)
@@ -269,7 +160,7 @@ server_start(char *path)
 	log_debug("socket path %s", socket_path);
 	setproctitle("server (%s)", rpathbuf);
 
-	srv_fd = server_create_socket();
+	server_fd = server_create_socket();
 	server_client_create(pair[1]);
 
 	if (access(SYSTEM_CFG, R_OK) == 0) {
@@ -282,7 +173,20 @@ server_start(char *path)
 	if (cfg_file != NULL && load_cfg(cfg_file, NULL, &cause) != 0)
 		goto error;
 
-	exit(server_main(srv_fd));
+	event_init();
+
+	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. */
@@ -291,150 +195,39 @@ error:
 	server_write_error(c, cause);
 	xfree(cause);
 
-	sigterm = 1;
-	server_shutdown();
+	server_shutdown = 1;
 
-	exit(server_main(srv_fd));
+	server_signal_set();
+	server_loop();
+	exit(1);
 }
 
 /* Main server loop. */
-int
-server_main(int srv_fd)
+void
+server_loop(void)
 {
-	struct pollfd	*pfds;
-	int		 nfds, xtimeout;
-	u_int		 i;
-	time_t		 now, last;
+	struct timeval	tv;
 
-	siginit();
-	log_debug("server socket is %d", srv_fd);
+	memset(&tv, 0, sizeof tv);
+	tv.tv_usec = POLL_TIMEOUT * 1000;
 
-	last = time(NULL);
+	while (!server_should_shutdown()) {
+		server_update_socket();
 
-	pfds = NULL;
-	for (;;) {
-		/* If sigterm, kill all windows and clients. */
-		if (sigterm)
-			server_shutdown();
-
-		/* Stop if no sessions or clients left. */
-		if (server_should_shutdown())
-			break;
-
-		/* Handle child exit. */
-		if (sigchld) {
-			sigchld = 0;
-			server_child_signal();
-			continue;
-		}
-
-		/* Recreate socket on SIGUSR1. */
-		if (sigusr1) {
-			sigusr1 = 0;
-			close(srv_fd);
-			srv_fd = server_create_socket();
-			continue;
-		}
-
-		/* Initialise pollfd array and add server socket. */
-		server_poll_reset();
-		server_poll_add(srv_fd, POLLIN, server_callback, NULL);
-
-		/* Fill window and client sockets. */
 		server_job_prepare();
 		server_window_prepare();
 		server_client_prepare();
-		
-		/* Update socket permissions. */
-		xtimeout = INFTIM;
-		if (server_update_socket() != 0)
-			xtimeout = POLL_TIMEOUT;
 
-		/* Do the poll. */
-		pfds = server_poll_flatten(&nfds);
-		if (poll(pfds, nfds, xtimeout) == -1) {
-			if (errno == EAGAIN || errno == EINTR)
-				continue;
-			fatal("poll failed");
-		}
-		server_poll_dispatch(pfds, nfds);
+		event_loopexit(&tv);
+		event_loop(EVLOOP_ONCE);
 
-		/* Call second-based timers. */
-		now = time(NULL);
-		if (now != last) {
-			last = now;
-			server_second_timers();
-		}
-
-		/* Run once-per-loop events. */
 		server_job_loop();
 		server_window_loop();
 		server_client_loop();
 
-		/* Collect any unset key bindings. */
 		key_bindings_clean();
-
-		/* Collect dead clients and sessions. */
 		server_clean_dead();
-	}
-	server_poll_reset();
-
-	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_client_lost(ARRAY_ITEM(&clients, i));
-	}
-	ARRAY_FREE(&clients);
-
-	mode_key_free_trees();
-	key_bindings_free();
-
-	close(srv_fd);
-
-	unlink(socket_path);
-	xfree(socket_path);
-
-	options_free(&global_s_options);
-	options_free(&global_w_options);
-
-	return (0);
-}
-
-/* Kill all clients. */
-void
-server_shutdown(void)
-{
-	struct session	*s;
-	struct client	*c;
-	u_int		 i, j;
-
-	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);
-		}
-	}
-
-	for (i = 0; i < ARRAY_LENGTH(&sessions); i++) {
-		s = ARRAY_ITEM(&sessions, i);
-		for (j = 0; j < ARRAY_LENGTH(&clients); j++) {
-			c = ARRAY_ITEM(&clients, j);
-			if (c != NULL && c->session == s) {
-				s = NULL;
-				break;
-			}
-		}
-		if (s != NULL)
-			session_destroy(s);
-	}
+	} 
 }
 
 /* Check if the server should be shutting down (no more clients or windows). */
@@ -454,49 +247,28 @@ server_should_shutdown(void)
 	return (1);
 }
 
-/* Handle SIGCHLD. */
+/* Shutdown the server by killing all clients and windows. */
 void
-server_child_signal(void)
+server_send_shutdown(void)
 {
-	struct window		*w;
-	struct window_pane	*wp;
-	struct job		*job;
-	int		 	 status;
-	pid_t		 	 pid;
-	u_int		 	 i;
+	struct client	*c;
+	struct session	*s;
+	u_int		 i;
 
-	for (;;) {
-		switch (pid = waitpid(WAIT_ANY, &status, WNOHANG|WUNTRACED)) {
-		case -1:
-			if (errno == ECHILD)
-				return;
-			fatal("waitpid failed");
-		case 0:
-			return;
+	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;
 		}
-		if (!WIFSTOPPED(status)) {
-			SLIST_FOREACH(job, &all_jobs, lentry) {
-				if (pid == job->pid) {
-					job->pid = -1;
-					job->status = status;
-				}
-			}
-			continue;
-		}
-		if (WSTOPSIG(status) == SIGTTIN || WSTOPSIG(status) == SIGTTOU)
-			continue;
+	}
 
-		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->pid == pid) {
-					if (killpg(pid, SIGCONT) != 0)
-						kill(pid, SIGCONT);
-				}
-			}
-		}
+	for (i = 0; i < ARRAY_LENGTH(&sessions); i++) {
+		if ((s = ARRAY_ITEM(&sessions, i)) != NULL)
+			session_destroy(s);
 	}
 }
 
@@ -525,12 +297,215 @@ server_clean_dead(void)
 	}
 }
 
-/* Call any once-per-second timers. */
+/* Update socket execute permissions based on whether sessions are attached. */
+int
+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);
+	}
+
+	return (n);
+}
+
+/* Callback for server socket. */
 void
-server_second_timers(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. */
+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) {
+				close(wp->fd);
+				wp->fd = -1;
+			}
+		}
+	}		
+
+	SLIST_FOREACH(job, &all_jobs, lentry) {
+		if (pid == job->pid) {
+			job->pid = -1;
+			job->status = status;
+		}
+	}
+}
+
+/* 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. */
+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"))
@@ -548,6 +523,11 @@ server_second_timers(void)
 				wp->mode->timer(wp);
 		}
 	}
+
+	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. */
@@ -606,32 +586,3 @@ server_lock_sessions(void)
 		}
 	}
 }
-
-/* Update socket execute permissions based on whether sessions are attached. */
-int
-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);
-	}
-
-	return (n);
-}