An Algorithm for ftpd Under the Hurd


  /* Create the socket.  */
  sock = make_socket (FTPD_PORT)
  listen (sock, 1)

  drop_all_permission ()  /* Become unknown.  */

  while (fd = listen (sock))
    {
      if (fork () > 0)
        {
          /* Child */
          accept (fd)

          prompt (name, password)

          if (password_check_user (name, password))
            /* Become user.  */
            ftp_session ()
          else
            /* Reject access.  */
           close ()
         }
    }