Proper error pages for content editors in admin theme. #drupal #d7

template.php

<?php

/**
 * Implements hook_process_HOOK().
 */
function THEME_process_page(&$vars) {

  $error_pages = array(
    403 => array(
      'title' => '403 Access Denied',
      'text' => 'You do not have access to this path.',
    ),
    404 => array(
      'title' => '404 Not Found',
      'text' => 'This path does not exist.',
    ),
  );

  $status = (int) drupal_get_http_header('status');
  if(isset($error_pages[$status])) {
    $content = $error_pages[$status];

    // Content editors might have edit access to error pages. Because Drupal
    // changes the current page's node context, we disable all local tasks to
    // prevent accidental editing of the displayed error node.
    $vars['primary_local_tasks'] = array();
    $vars['secondary_local_tasks'] = array();
    $vars['tabs'] = array();

    // Error nodes are usally meant for frontend consumption and might break
    // when displaying them in the admin theme.
    $vars['page']['content'] = array();

    $vars['title'] = check_plain(t($content['title']));
    $vars['page']['content']['#markup'] = check_plain(t($content['text']));
  }
}