Determine whether the user has a given privilege.

Parameters

$string: The permission, such as "administer nodes", being checked for.

$account: (optional) The account to check, if not given use currently logged in user.

$reset: (optional) Resets the user's permissions cache, which will result in a recalculation of the user's permissions. This is necessary to support dynamically added user roles.

Return value

Boolean TRUE if the current user has the requested permission.

All permission checks in Drupal should go through this function. This way, we guarantee consistent behavior, and ensure that the superuser can perform all actions.

File

drupal-6.x/modules/user/user.module, line 511

Enables the user registration and login system.

Code

function user_access($string, $account = NULL, $reset = FALSE) {
  global $user;
  static $perm = array();

  if ($reset) {
    $perm = array();
  }

  if (!isset($account)) {
    $account = $user;
  }

  // User #1 has all privileges:
  if ($account->uid == 1) {
    return TRUE;
  }

  // To reduce the number of SQL queries, we cache the user's permissions
  // in a static variable.
  if (!isset($perm[$account->uid])) {
    $result = db_query("SELECT p.perm FROM {role} r INNER JOIN {permission} p ON p.rid = r.rid WHERE r.rid IN (" . db_placeholders($account->roles) . ")", array_keys($account->roles));

    $perms = array();
    while ($row = db_fetch_object($result)) {
      $perms += array_flip(explode(', ', $row->perm));
    }
    $perm[$account->uid] = $perms;
  }

  return isset($perm[$account->uid][$string]);
}