From 45c928e2f58e23a9daac1b92a11bbb33e5058871 Mon Sep 17 00:00:00 2001
From: Krishna Srinivas <krishna@minio.io>
Date: Mon, 22 Aug 2016 22:50:01 +0530
Subject: [PATCH] boot: checkPortAvailability() should fail only for EADDRINUSE
 error and ignore other errors. (#2527)

fixes #2510
---
 cmd/checkport.go | 25 ++++++++++++++++++++++++-
 1 file changed, 24 insertions(+), 1 deletion(-)

diff --git a/cmd/checkport.go b/cmd/checkport.go
index 0e354c592..c1fb9531c 100644
--- a/cmd/checkport.go
+++ b/cmd/checkport.go
@@ -19,6 +19,8 @@ package cmd
 import (
 	"fmt"
 	"net"
+	"os"
+	"syscall"
 )
 
 // Make sure that none of the other processes are listening on the
@@ -35,7 +37,13 @@ func checkPortAvailability(port int) error {
 	for _, n := range network {
 		l, err := net.Listen(n, fmt.Sprintf(":%d", port))
 		if err != nil {
-			return err
+			if isAddrInUse(err) {
+				// Return error if another process is listening on the
+				// same port.
+				return err
+			}
+			// Ignore any other error (ex. EAFNOSUPPORT)
+			continue
 		}
 
 		// look for error so we don't have dangling connection
@@ -46,3 +54,18 @@ func checkPortAvailability(port int) error {
 
 	return nil
 }
+
+// Return true if err is "address already in use" error.
+// syscall.EADDRINUSE is available on all OSes.
+func isAddrInUse(err error) bool {
+	if opErr, ok := err.(*net.OpError); ok {
+		if sysErr, ok := opErr.Err.(*os.SyscallError); ok {
+			if errno, ok := sysErr.Err.(syscall.Errno); ok {
+				if errno == syscall.EADDRINUSE {
+					return true
+				}
+			}
+		}
+	}
+	return false
+}