title: Unable to initialize UNIXServer with vagrant
body: <p>It looks like some permissions issues:</p>
  
  <pre><code>$ irb
  require 'socket'; UNIXServer.new('/vagrant/tmp/sock')
  =&gt; Errno::EPERM: Operation not permitted - "/vagrant/tmp/sock"
  </code></pre>
  
  <p>But user <code>vagrant</code> has permissions to write in <code>/vagrant/tmp</code></p>
  
  <pre><code>$ whoami
  vagrant
  
  $ ls -la /vagrant/tmp
  total 0
  drwxr-xr-x 1 vagrant vagrant  68 Feb 22 23:18 .
  </code></pre>
  
  <p>So it's not obvious for me what's going wrong. I use latest ruby</p>
  
  <pre><code>$ ruby -v
  ruby 2.0.0p598 (2014-11-13 revision 48408) [x86_64-linux]
  </code></pre>
  
  <p>And ubuntu 14.04:</p>
  
  <pre><code># -*- mode: ruby -*-
  # vi: set ft=ruby :
  
  VAGRANTFILE_API_VERSION = "2"
  
  Vagrant.configure(VAGRANTFILE_API_VERSION) do |config|
    config.vm.box = "ubuntu/trusty64"
    config.vm.network "forwarded_port", guest: 3000, host: 3000
  end
  </code></pre>