File X11-displaymanager-gdm of Package gdm

gdm_vars() {
    case "${DISPLAYMANAGER##*/}" in
        gdm|GDM|Gnome|GNOME)
            RELOADSIGNAL="-USR1"
            DISPLAYMANAGER=/usr/sbin/gdm
            PIDFILE=/run/gdm/gdm.pid
            return 0 ;;
       *) return 1 ;;
    esac

    return 1
}