From 44ac6e9295f213707709d38ed1d7c55969a06c83 Mon Sep 17 00:00:00 2001
From: Ahmad Wilson <ahmad.wilson@brigade.com>
Date: Fri, 24 Mar 2017 20:18:12 +0000
Subject: [PATCH] Refactor exposed port identification

The previous mechanism for identifying exposed ports on
host machines was flakey and not really an ideal/efficient
means of identifying exposed ports (i.e attempting to connect
to port with a 1 second timeout). This change modifies the method
to make use of netstat and varies the usage based on the host
OS appropriately.
---
 Dockerfile | 2 +-
 bin/dock   | 7 ++++++-
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/Dockerfile b/Dockerfile
index 72bc5c5..81d93ae 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -5,7 +5,7 @@ RUN yum -y install \
     # Docker daemon won't start without `iptables` installed
     iptables-services \
     # Used for a variety of simple tests for port forwarding/publishing
-    nmap-ncat \
+    nmap-ncat net-tools \
     # Allow `dock-user` to escalate privileges if necessary
     sudo \
     # Allow us to run using OverlayFS file system
diff --git a/bin/dock b/bin/dock
index dad3b23..48f3be8 100755
--- a/bin/dock
+++ b/bin/dock
@@ -693,7 +693,12 @@ destroy_container() {
 }
 
 port_taken_on_localhost() {
-  echo | nc -w 1 localhost $1 >/dev/null 2>&1
+  if osx; then
+    # show -a(ll sockets) and -n(umeric addresses)
+    echo | netstat -a -n 2>/dev/null | grep $1 >/dev/null 2>&1
+  else
+    echo | netstat --numeric --listening 2>/dev/null | grep $1 >/dev/null 2>&1
+  fi
 }
 
 process_exposed_ports() {