Use a socketpair to synchronise server startup.

client.c

@@ -1,4 +1,4 @@
-/* $Id: client.c,v 1.28 2008-06-02 21:08:36 nicm Exp $ */
+/* $Id: client.c,v 1.29 2008-06-07 07:27:28 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicm@users.sourceforge.net>
@@ -51,11 +51,9 @@ client_init(const char *path, struct client_ctx *cctx, int start_server)
 	retries = 0;
 retry:
 	if (stat(path, &sb) != 0) {
-		if (start_server && errno == ENOENT && retries < 10) {
+		if (start_server && errno == ENOENT) {
-			if (pid == 0)
+			if (server_start(path) != 0)
-				pid = server_start(path);
+				goto no_start;
-			usleep(10000);
-			retries++;
 			goto retry;
 		}
 		goto fail;
@@ -81,9 +79,8 @@ retry:
 		if (start_server && errno == ECONNREFUSED && retries < 10) {
 			if (unlink(path) != 0)
 				goto fail;
-			usleep(10000);
+			if (server_start(path) != 0)
-			retries++;
+				goto no_start;
-			goto retry;
 		}
 		goto fail;
 	}
@@ -112,6 +109,10 @@ retry:
 
 	return (0);
 
+no_start:
+	log_warnx("server failed to start");
+	return (1);
+
 fail:
 	log_warn("server not found");
 	return (1);

server.c

@@ -1,4 +1,4 @@
-/* $Id: server.c,v 1.58 2008-06-07 07:13:08 nicm Exp $ */
+/* $Id: server.c,v 1.59 2008-06-07 07:27:28 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicm@users.sourceforge.net>
@@ -58,24 +58,37 @@ void		 server_check_redraw(struct client *);
 void		 server_check_status(struct client *);
 
 /* Fork new server. */
-pid_t
+int
 server_start(const char *path)
 {
 	struct sockaddr_un	sa;
 	size_t			size;
 	mode_t			mask;
-	int		   	n, fd, mode;
+	int		   	n, fd, pair[2], mode;
-	pid_t			pid;
 	char		       *cause;
+	u_char			ch;
 
-	switch (pid = fork()) {
+	/* 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");
+		fatal("fork failed");
 	case 0:
 		break;
 	default:
-		return (pid);
+		close(pair[1]);
+
+		ch = 0;
+		if (read(pair[0], &ch, 1) == 1 && ch == 0xff) {
+			close(pair[0]);
+			return (0);
+		}
+		close(pair[0]);
+		return (1);
 	}
+	close(pair[0]);
 
 #ifdef DEBUG
 	xmalloc_clear();
@@ -130,6 +143,11 @@ server_start(const char *path)
 		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");
+	/* Don't close the socketpair fd on success. */
 	
 	n = server_main(path, fd);
 #ifdef DEBUG

session.c

@@ -1,4 +1,4 @@
-/* $Id: session.c,v 1.36 2008-06-06 17:55:27 nicm Exp $ */
+/* $Id: session.c,v 1.37 2008-06-07 07:27:28 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicm@users.sourceforge.net>
@@ -116,7 +116,7 @@ session_create(const char *name, const char *cmd, u_int sx, u_int sy)
 
 	s = xmalloc(sizeof *s);
 	if (clock_gettime(CLOCK_REALTIME, &s->ts) != 0)
-		fatal("clock_gettime");
+		fatal("clock_gettime failed");
 	s->curw = s->lastw = NULL;
 	RB_INIT(&s->windows);
 	TAILQ_INIT(&s->alerts);

status.c

@@ -1,4 +1,4 @@
-/* $Id: status.c,v 1.23 2008-06-07 06:13:21 nicm Exp $ */
+/* $Id: status.c,v 1.24 2008-06-07 07:27:28 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicm@users.sourceforge.net>
@@ -43,7 +43,7 @@ status_write_client(struct client *c)
 		return;
 
 	if (clock_gettime(CLOCK_REALTIME, &c->status_ts) != 0)
-		fatal("clock_gettime");
+		fatal("clock_gettime failed");
 
 	left = options_get_string(&c->session->options, "status-left");
 	strftime(lbuf, sizeof lbuf, left, localtime(&(c->status_ts.tv_sec)));

tmux.h

@@ -1,4 +1,4 @@
-/* $Id: tmux.h,v 1.138 2008-06-07 07:13:08 nicm Exp $ */
+/* $Id: tmux.h,v 1.139 2008-06-07 07:27:28 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicm@users.sourceforge.net>
@@ -895,7 +895,7 @@ const char *key_string_lookup_key(int);
 
 /* server.c */
 extern struct clients clients;
-pid_t	 server_start(const char *);
+int	 server_start(const char *);
 
 /* server-msg.c */
 int	 server_msg_dispatch(struct client *);