Sync OpenBSD patchset 225:

If there is an error in the configuration file, don't just exit(1) as this can
cause the client to hang. Instead, send the error message, then mark the client
as bad and start a normal shutdown so the server exits once the error is
written.

This also allows some code duplicating daemon(3) to be trimmed and logging to
begin earlier.

Prompted by Theo noticing the behaviour on error wasn't documented.

1 files changed, 47 insertions, 40 deletions

diff --git a/server.c b/server.c
index aa5a4292..98897316 100644
--- a/server.c
+++ b/server.c
@@ -1,4 +1,4 @@
-/* $Id: server.c,v 1.164 2009-07-28 23:11:18 tcunha Exp $ */
+/* $Id: server.c,v 1.165 2009-08-09 17:19:18 tcunha Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicm@users.sourceforge.net>
@@ -130,10 +130,11 @@ server_client_index(struct client *c)
 int
 server_start(char *path)
 {
-	int	pair[2], srv_fd, null_fd;
-	char   *cause;
+	struct client	*c;
+	int		 pair[2], srv_fd;
+	char		*cause;
 #ifdef HAVE_SETPROCTITLE
-	char	rpathbuf[MAXPATHLEN];
+	char		 rpathbuf[MAXPATHLEN];
 #endif
 
 	/* The first client is special and gets a socketpair; create it. */
@@ -155,9 +156,12 @@ server_start(char *path)
 	 * 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)
+	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(&sessions);
@@ -172,47 +176,39 @@ server_start(char *path)
 	start_time = time(NULL);
 	socket_path = path;
 
-	if (access(SYSTEM_CFG, R_OK) != 0) {
-		if (errno != ENOENT) {
-			log_warn("%s", SYSTEM_CFG);
-			exit(1);
-		}
-	} else {
-		if (load_cfg(SYSTEM_CFG, &cause) != 0) {
-			log_warnx("%s", cause);
-			exit(1);
-		}
-	}
-	if (cfg_file != NULL && load_cfg(cfg_file, &cause) != 0) {
-		log_warnx("%s", cause);
-		exit(1);
-	}
-	logfile("server");
-
-	/*
-	 * Close stdin/stdout/stderr. Can't let daemon() do this as they are
-	 * needed until now to print configuration file errors.
-	 */
-        if ((null_fd = open(_PATH_DEVNULL, O_RDWR)) != -1) {
-                dup2(null_fd, STDIN_FILENO);
-                dup2(null_fd, STDOUT_FILENO);
-                dup2(null_fd, STDERR_FILENO);
-                if (null_fd > 2)
-                        close(null_fd);
-        }
-
-	log_debug("server started, pid %ld", (long) getpid());
-	log_debug("socket path %s", socket_path);
-
 #ifdef HAVE_SETPROCTITLE
 	if (realpath(socket_path, rpathbuf) == NULL)
 		strlcpy(rpathbuf, socket_path, sizeof rpathbuf);
+	log_debug("socket path %s", socket_path);
 	setproctitle("server (%s)", rpathbuf);
 #endif
 
 	srv_fd = server_create_socket();
 	server_create_client(pair[1]);
 
+	if (access(SYSTEM_CFG, R_OK) != 0) {
+		if (errno != ENOENT) {
+			xasprintf(
+			    &cause, "%s: %s", strerror(errno), SYSTEM_CFG);
+			goto error;
+		}
+	} else if (load_cfg(SYSTEM_CFG, &cause) != 0)
+		goto error;
+	if (cfg_file != NULL && load_cfg(cfg_file, &cause) != 0)
+		goto error;
+
+	exit(server_main(srv_fd));
+
+error:
+	/* Write the error and shutdown the server. */
+	c = ARRAY_FIRST(&clients);
+
+	server_write_error(c, cause);
+	xfree(cause);
+
+	server_shutdown();
+	c->flags |= CLIENT_BAD;
+
 	exit(server_main(srv_fd));
 }
 
@@ -424,8 +420,13 @@ server_shutdown(void)
 
 	for (i = 0; i < ARRAY_LENGTH(&clients); i++) {
 		c = ARRAY_ITEM(&clients, i);
-		if (c != NULL)
-			server_write_client(c, MSG_SHUTDOWN, NULL, 0);
+		if (c != NULL) {
+			if (c->flags & CLIENT_BAD)
+				server_lost_client(c);
+			else
+				server_write_client(c, MSG_SHUTDOWN, NULL, 0);
+			c->flags |= CLIENT_BAD;
+		}
 	}
 }
 
@@ -677,7 +678,8 @@ server_fill_clients(struct pollfd **pfd)
 			(*pfd)->fd = -1;
 		else {
 			(*pfd)->fd = c->fd;
-			(*pfd)->events = POLLIN;
+			if (!(c->flags & CLIENT_BAD))
+				(*pfd)->events = POLLIN;
 			if (BUFFER_USED(c->out) > 0)
 				(*pfd)->events |= POLLOUT;
 		}
@@ -725,6 +727,11 @@ server_handle_clients(struct pollfd **pfd)
 				server_lost_client(c);
 				(*pfd) += 2;
 				continue;
+			} else if (c->flags & CLIENT_BAD) {
+				if (BUFFER_USED(c->out) == 0)
+					server_lost_client(c);
+				(*pfd) += 2;
+				continue;			
 			} else
 				server_msg_dispatch(c);
 		}