include ip address while doing checkPortAvailability (#7818)

While checking for port availability, ip address should be included.
When a machine has multiple ip addresses, multiple minio instances
or some other applications can be run on same port but different
ip address.

Fixes #7685

cmd/gateway-main.go

@@ -121,7 +121,7 @@ func StartGateway(ctx *cli.Context, gw Gateway) {
 	// to IPv6 address ie minio will start listening on IPv6 address whereas another
 	// (non-)minio process is listening on IPv4 of given port.
 	// To avoid this error situation we check for port availability.
-	logger.FatalIf(checkPortAvailability(globalMinioPort), "Unable to start the gateway")
+	logger.FatalIf(checkPortAvailability(globalMinioHost, globalMinioPort), "Unable to start the gateway")
 
 	// Check and load TLS certificates.
 	var err error

cmd/net.go

@@ -190,10 +190,10 @@ func isHostIP(ipAddress string) bool {
 	return net.ParseIP(host) != nil
 }
 
-// checkPortAvailability - check if given port is already in use.
+// checkPortAvailability - check if given host and port is already in use.
 // Note: The check method tries to listen on given port and closes it.
 // It is possible to have a disconnected client in this tiny window of time.
-func checkPortAvailability(port string) (err error) {
+func checkPortAvailability(host, port string) (err error) {
 	// Return true if err is "address already in use" error.
 	isAddrInUseErr := func(err error) (b bool) {
 		if opErr, ok := err.(*net.OpError); ok {
@@ -209,7 +209,7 @@ func checkPortAvailability(port string) (err error) {
 
 	network := []string{"tcp", "tcp4", "tcp6"}
 	for _, n := range network {
-		l, err := net.Listen(n, net.JoinHostPort("", port))
+		l, err := net.Listen(n, net.JoinHostPort(host, port))
 		if err == nil {
 			// As we are able to listen on this network, the port is not in use.
 			// Close the listener and continue check other networks.

cmd/net_test.go

@@ -206,11 +206,13 @@ func TestCheckPortAvailability(t *testing.T) {
 	defer listener.Close()
 
 	testCases := []struct {
+		host        string
 		port        string
 		expectedErr error
 	}{
-		{port, fmt.Errorf("listen tcp :%v: bind: address already in use", port)},
-		{getFreePort(), nil},
+		{"", port, fmt.Errorf("listen tcp :%v: bind: address already in use", port)},
+		{"127.0.0.1", port, fmt.Errorf("listen tcp 127.0.0.1:%v: bind: address already in use", port)},
+		{"", getFreePort(), nil},
 	}
 
 	for _, testCase := range testCases {
@@ -219,7 +221,7 @@ func TestCheckPortAvailability(t *testing.T) {
 			continue
 		}
 
-		err := checkPortAvailability(testCase.port)
+		err := checkPortAvailability(testCase.host, testCase.port)
 		if testCase.expectedErr == nil {
 			if err != nil {
 				t.Fatalf("error: expected = <nil>, got = %v", err)

cmd/server-main.go

@@ -176,7 +176,7 @@ func serverHandleCmdArgs(ctx *cli.Context) {
 	// to IPv6 address ie minio will start listening on IPv6 address whereas another
 	// (non-)minio process is listening on IPv4 of given port.
 	// To avoid this error sutiation we check for port availability.
-	logger.FatalIf(checkPortAvailability(globalMinioPort), "Unable to start the server")
+	logger.FatalIf(checkPortAvailability(globalMinioHost, globalMinioPort), "Unable to start the server")
 
 	globalIsXL = (setupType == XLSetupType)
 	globalIsDistXL = (setupType == DistXLSetupType)