drupal/modules/php/php.install

<?php
// $Id$

/**
 * @file
 * Install, update and uninstall functions for the php module.
 */

/**
 * Implement hook_install().
 */
function php_install() {
  $format_exists = (bool) db_query_range('SELECT 1 FROM {filter_format} WHERE name = :name', 0, 1, array(':name' => 'PHP code'))->fetchField();
  // Add a PHP code text format, if it does not exist. Do this only for the
  // first install (or if the format has been manually deleted) as there is no
  // reliable method to identify the format in an uninstall hook or in
  // subsequent clean installs.
  if (!$format_exists) {
    $format = db_insert('filter_format')
      ->fields(array(
        'name' => 'PHP code',
        'cache' => 0,
      ))
      ->execute();

    // Enable the PHP evaluator filter.
    db_insert('filter')
      ->fields(array(
        'format' => $format,
        'module' => 'php',
        'name' => 'php_code',
        'weight' => 0,
        'status' => 1,
      ))
      ->execute();

    drupal_set_message(t('A !php-code text format has been created.', array('!php-code' => l('PHP code', 'admin/config/content/formats/' . $format))));
  }
}

/**
 * Implement hook_disable().
 */
function php_disable() {
  drupal_set_message(t('The PHP module has been disabled. Please note that any existing content that was using the PHP filter will now be visible in plain text. This might pose a security risk by exposing sensitive information, if any, used in the PHP code.'));
}