title: How to get the root dir of the Symfony2 application?
body: <p>What is the best way to get the root app directory from inside the controller? Is it possible to get it outside of the controller?</p>
  
  <p>Now I get it by passing it (from parameters) to the service as an argument, like this:</p>
  
  <pre><code>services:
  
      sr_processor:
          class: Pro\Processor
          arguments: [%kernel.root_dir%]
  </code></pre>
  
  <p>Is there a better, simpler way to get this information in Symfony2?</p>