From: Simon Pasquier <spasquie@redhat.com>
Date: Thu, 3 May 2018 15:20:17 +0000 (+0200)
Subject: prober: fix data races
X-Git-Url: https://vcs.fsf.org/?a=commitdiff_plain;h=c750a1520ce8a39cbdbb0ac47376ef0a8b53b41e;p=blackbox_exporter.git

prober: fix data races

Signed-off-by: Simon Pasquier <spasquie@redhat.com>
---

diff --git a/prober/dns_test.go b/prober/dns_test.go
index 2e66a5d..e40f431 100644
--- a/prober/dns_test.go
+++ b/prober/dns_test.go
@@ -34,18 +34,31 @@ var PROTOCOLS = [...]string{"udp", "tcp"}
 func startDNSServer(protocol string, handler func(dns.ResponseWriter, *dns.Msg)) (*dns.Server, net.Addr) {
 	h := dns.NewServeMux()
 	h.HandleFunc(".", handler)
+
 	server := &dns.Server{Addr: ":0", Net: protocol, Handler: h}
-	go server.ListenAndServe()
-	// Wait until PacketConn becomes available, but give up after 1 second.
-	for i := 0; server.PacketConn == nil && i < 200; i++ {
-		if protocol == "tcp" && server.Listener != nil {
-			break
+	if protocol == "udp" {
+		a, err := net.ResolveUDPAddr(server.Net, server.Addr)
+		if err != nil {
+			panic(err)
+		}
+		l, err := net.ListenUDP(server.Net, a)
+		if err != nil {
+			panic(err)
 		}
-		if protocol == "udp" && server.PacketConn != nil {
-			break
+		server.PacketConn = l
+	} else {
+		a, err := net.ResolveTCPAddr(server.Net, server.Addr)
+		if err != nil {
+			panic(err)
+		}
+		l, err := net.ListenTCP(server.Net, a)
+		if err != nil {
+			panic(err)
 		}
-		time.Sleep(5 * time.Millisecond)
+		server.Listener = l
 	}
+	go server.ActivateAndServe()
+
 	if protocol == "tcp" {
 		return server, server.Listener.Addr()
 	}