openvpn.sh: Add wrapper script

* Add the beginning of a wrapper script that will handle cert generation
  and OpenVPN invocation.

Dockerfile

@@ -5,7 +5,12 @@ FROM ubuntu:14.04
 MAINTAINER Kyle Manna <kyle@kylemanna.com>
 
 RUN apt-get install -y openvpn iptables curl
+
 ADD ./bin /usr/local/sbin
+RUN chmod a+x /usr/local/sbin/*
+
 VOLUME /etc/openvpn
+
 EXPOSE 443/tcp 1194/udp 8080/tcp
-CMD run
+
+ENTRYPOINT ["openvpn.sh"]

bin/openvpn.sh

@@ -0,0 +1,25 @@
+#!/bin/bash
+#
+# OpenVPN + Docker Wrapper Script
+#
+
+set -ex
+
+abort() {
+    echo "Error: $@"
+    exit 1
+}
+
+if [ $# -lt 1 ]; then
+    abort "No command specified"
+fi
+
+# Read arguments from command line
+cmd=$1
+shift
+
+case "$cmd" in
+    *)
+        abort "Unknown cmd \"$cmd\""
+        ;;
+esac