From 2783f02790967aa7a163030f9fe7fcf0b42e078a Mon Sep 17 00:00:00 2001
From: Alvaro Saurin <alvaro.saurin@gmail.com>
Date: Fri, 1 May 2015 10:53:16 +0200
Subject: [PATCH] Make Stop() idempotent

---
 nameserver/server.go | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/nameserver/server.go b/nameserver/server.go
index f2bc6d99..c26bc63b 100644
--- a/nameserver/server.go
+++ b/nameserver/server.go
@@ -232,14 +232,21 @@ func (s *DNSServer) Status() string {
 // Perform a graceful shutdown
 func (s *DNSServer) Stop() error {
 	// Stop the listeners/handlers
-	if err := s.tcpSrv.Shutdown(); err != nil {
-		return err
+	if s.tcpSrv != nil {
+		if err := s.tcpSrv.Shutdown(); err != nil {
+			return err
+		}
+		s.lst.Close()
+		s.tcpSrv = nil
 	}
-	if err := s.udpSrv.Shutdown(); err != nil {
-		return err
+	if s.udpSrv != nil {
+		if err := s.udpSrv.Shutdown(); err != nil {
+			return err
+		}
+		s.pc.Close()
+		s.udpSrv = nil
 	}
 	s.listenersWg.Wait()
-
 	return nil
 }