Fix bug #5267 - nmbd shuts down when network interfaces go down.

Cause nmbd to wait for an interface, in a mode where SIGTERM
will kills us (same way we wait on startup for an interface).
Jeremy.
(This used to be commit 5440c752ff270cc674d46f2dfa2ceb47dac030f6)

1 files changed, 39 insertions, 29 deletions

diff --git a/source3/nmbd/nmbd.c b/source3/nmbd/nmbd.c
index 378b6f3dbe..00d252940a 100644
--- a/source3/nmbd/nmbd.c
+++ b/source3/nmbd/nmbd.c
@@ -163,23 +163,31 @@ static void expire_names_and_servers(time_t t)
 
 /************************************************************************** **
  Reload the list of network interfaces.
+ Doesn't return until a network interface is up.
  ************************************************************************** */
 
-static bool reload_interfaces(time_t t)
+static void reload_interfaces(time_t t)
 {
 	static time_t lastt;
 	int n;
 	struct subnet_record *subrec;
 
-	if (t && ((t - lastt) < NMBD_INTERFACES_RELOAD)) return False;
+	if (t && ((t - lastt) < NMBD_INTERFACES_RELOAD)) {
+		return;
+	}
+
 	lastt = t;
 
-	if (!interfaces_changed()) return False;
+	if (!interfaces_changed()) {
+		return;
+	}
 
 	/* the list of probed interfaces has changed, we may need to add/remove
 	   some subnets */
 	load_interfaces();
 
+  try_again:
+
 	/* find any interfaces that need adding */
 	for (n=iface_count() - 1; n >= 0; n--) {
 		char str[INET6_ADDRSTRLEN];
@@ -268,12 +276,33 @@ static bool reload_interfaces(time_t t)
 
 	rescan_listen_set = True;
 
-	/* We need to shutdown if there are no subnets... */
+	/* We need to wait if there are no subnets... */
 	if (FIRST_SUBNET == NULL) {
-		DEBUG(0,("reload_interfaces: No subnets to listen to. Shutting down...\n"));
-		return True;
+		void (*saved_handler)(int);
+
+		DEBUG(0,("reload_interfaces: "
+			"No subnets to listen to. Waiting..\n"));
+
+		/*
+		 * Whilst we're waiting for an interface, allow SIGTERM to
+		 * cause us to exit.
+		 */
+
+		saved_handler = CatchSignal( SIGTERM, SIGNAL_CAST SIG_DFL );
+
+		/* We only count IPv4 interfaces here. */
+		while (iface_count_v4() == 0) {
+			sleep(5);
+			load_interfaces();
+		}
+
+		/*
+		 * We got an interface, restore our normal term handler.
+		 */
+
+		CatchSignal( SIGTERM, SIGNAL_CAST saved_handler );
+		goto try_again;
 	}
-	return False;
 }
 
 /**************************************************************************** **
@@ -310,8 +339,6 @@ static bool reload_nmbd_services(bool test)
 
 /**************************************************************************** **
  * React on 'smbcontrol nmbd reload-config' in the same way as to SIGHUP
- * We use buf here to return bool result to process() when reload_interfaces()
- * detects that there are no subnets.
  **************************************************************************** */
 
 static void msg_reload_nmbd_services(struct messaging_context *msg,
@@ -324,14 +351,7 @@ static void msg_reload_nmbd_services(struct messaging_context *msg,
 	dump_all_namelists();
 	reload_nmbd_services( True );
 	reopen_logs();
-	
-	if (data->data) {
-		/* We were called from process() */
-		/* If reload_interfaces() returned True */
-		/* we need to shutdown if there are no subnets... */
-		/* pass this info back to process() */
-		*((bool *)data->data) = reload_interfaces(0);  
-	}
+	reload_interfaces(0);
 }
 
 static void msg_nmbd_send_packet(struct messaging_context *msg,
@@ -401,7 +421,6 @@ static void msg_nmbd_send_packet(struct messaging_context *msg,
 static void process(void)
 {
 	bool run_election;
-	bool no_subnets;
 
 	while( True ) {
 		time_t t = time(NULL);
@@ -612,26 +631,17 @@ static void process(void)
 		 */
 
 		if(reload_after_sighup) {
-			DATA_BLOB blob = data_blob_const(&no_subnets,
-							 sizeof(no_subnets));
 			DEBUG( 0, ( "Got SIGHUP dumping debug info.\n" ) );
 			msg_reload_nmbd_services(nmbd_messaging_context(),
 						 NULL, MSG_SMB_CONF_UPDATED,
-						 procid_self(), &blob);
+						 procid_self(), NULL);
 
-			if(no_subnets) {
-				TALLOC_FREE(frame);
-				return;
-			}
 			reload_after_sighup = 0;
 		}
 
 		/* check for new network interfaces */
 
-		if(reload_interfaces(t)) {
-			TALLOC_FREE(frame);
-			return;
-		}
+		reload_interfaces(t);
 
 		/* free up temp memory */
 		TALLOC_FREE(frame);