ensure_admin ()
{
# Description: Function to elevate priviledges of script execution and to ensure administrative privileges
# such that system wide settings or configuration may be done.
#
# This function evaluates and uses multiple ways to elevate priviledges based on the environment. In an
# X session; and normal GUI w. systemd: elevate privs with normal GUI policy kit, otherwise try dialog
# menu system and cached sudo, and finally fall back on good old sudo. Since scripts may be launched with
# a GUI front (for user interaction) end and NO terminal; it is really preferable to display a proper
# priviledge escalation propt in a GUI format and only use sudo in cases where there is a terminal or
# no other option is present.
#
# Should the function not discover an X session, then dialog will be preferred over regular sudo.
#
# Globals: $UID
# Arguments: None
# Outputs: GUI
# Dependencies: soft dependency on "dialog", will fall back on CLI if dialog is absent.
# Returns: relaunches script under sudo.
# Usage: The function expects no arguments, but will prompt for system password if required.
# Usage: ensure_admin
#
# End of documentation

    if [ ! "$UID" -eq 0 ]; then
        if xset q &>/dev/null; then
            # If X is running in this session then...
            if echo $(systemctl get-default ) |grep graphical &>/dev/null ; then
                # If we are a normal GUI w. systemd: elevate privs with normal GUI policy kit...
                write_information "Allowing root to display menus..."
                xhost local:root
                write_information "Authenticating..."
                pkexec env DISPLAY=$DISPLAY XAUTHORITY=$XAUTHORITY ${0}
                exit
            else
                # If we are some other kind of archane GUI then...
                write_information "Allowing root to display menus..."
                xhost local:root
                write_information "Checking for dialog..."
                if hash dialog 2>/dev/null ; then
                    token=$(dialog --title "${Title:-"sudo"}" --backtitle "${BackTitle:-"$( basename $0 )"}" --insecure --stdout --passwordbox "\n This functionality requires elevated priviledges. \n Please provide your (sudo) password" 10 90)
                    ret=$? ; clear
                    case $ret in
                        0)
                            export HISTIGNORE='*sudo -S*'
                            echo ${token} | sudo -S -v || ensure_admin
                            sudo DISPLAY=$DISPLAY /bin/bash ${0} $@ || rtd_oem_pause 1
                        ;;
                        1) echo "Request cancelled" ;;
                        255) echo "[esc] Request aborted" ;;
                        * )  exit 1
                    esac
                    exit
                else
                    # If we have some kind of X but not even "dialog" then...
                    write_information "Dialog not found..."
                    write_warning "This script needs administrative access..."
                    xhost local:root
                    sudo DISPLAY=$DISPLAY bash "${0}" "$@" || rtd_oem_pause 1
                    exit
                fi
            fi
        else
            # If there is no X in this session...
            write_information "No X server at \$DISPLAY [$DISPLAY]"
            # Use dialog if possible, otherwise just terminal...
            if hash dialog 2>/dev/null ; then
                token=$(dialog --title "${Title:-"sudo"}" --backtitle "${BackTitle:-"$( basename $0 )"}" --insecure --stdout --passwordbox "\n This functionality requires elevated priviledges. \n Please provide your (sudo) password" 10 90)
                ret=$? ; clear
                case $ret in
                    0)
                        export HISTIGNORE='*sudo -S*'
                        echo ${token} | sudo -S -v || ensure_admin
                        sudo DISPLAY=$DISPLAY /bin/bash ${0} $@ || rtd_oem_pause 1
                    ;;
                    1) echo "Request cancelled" ;;
                    255) echo "[esc] Request aborted" ;;
                    * )  exit 1
                esac
                exit
            else
                write_warning "This script needs administrative access..."
                sudo DISPLAY=$DISPLAY bash "${0}" "$@" || rtd_oem_pause 1
                exit
            fi
        fi
    else
        sudo sed -i s/'# session  optional       pam_xauth.so'/'session  optional       pam_xauth.so'/g /etc/pam.d/sudo
    fi
}