function parent-user() {
    pid=${1:-$$}
    uid=${2:-$(piduser $pid)}
    stat=($(</proc/${pid}/stat))
    ppid=${stat[4]}; echo $ppid
    puid=$(piduser $ppid )

    if [[ ${puid} != $uid ]]; then
        echo ${puid}
    elif [[ $ppid != 1 ]]; then
        parent-user ${ppid}
    fi
}