make-systemd-xvnc

#!/bin/bash
#
# Prompts for VNC screen resolutions and builds the appropriate xvnc .socket/.service files
# Must be run as root
#


function askyn() {
    local ans
    echo -n "$1" '[y/n]? ' ; read $2 ans
    case "$ans" in
        y*|Y*) return 0 ;;
        *) return 1 ;;
    esac
}


[[ ! $EUID -eq 0 ]] && notroot=0 || notroot=1
    
if [ "$1" == "" ]
then
    [ $notroot -eq 0 ] && echo "? You must be root to write to the system" && echo "  Or start with 'sudo $0'" && exit
    sdir="/etc/systemd/system"
else
    sdir="$1"
fi

# Which VNC server is installed?
#
vncsrv=""
extrasw=""
[ -f /usr/bin/Xtightvnc -a -f /usr/bin/Xtigervnc ] && echo "%% Both xtigervnc and xtightvnc are installed; using xtigervnc"
[ -f /usr/bin/Xtightvnc ] && vncsrv="/usr/bin/Xtightvnc" 
[ -f /usr/bin/Xtigervnc ] && vncsrv="/usr/bin/Xtigervnc" && extrasw="-noreset -SecurityTypes None"
[ "$vncsrv" == "" ] && echo "? Cannot find either Xtigervnc or Xtightvnc" && echo "  Please 'sudo apt install' a VNC Server (tigervnc-standalone-server or tightvncserver)" && exit
echo "% Configuring dynamic VNC to use '$vncsrv'"
#
# See if old xvnc*.socket files exist
#
n=1
if [ -f "$sdir/xvnc0.socket" -o -f "$sdir/xvnc1.socket" ]
then
    echo "% xvnc* systemd socket/service pairs already exist"
    echo "  You can replace them or create new ones at the end of the 'list'"
    echo "  Enter Y to replace existing files or N to leave existing files and add new socket/service pairs"
    if ! askyn " Do you want to replace the existing xvnc* socket/services?"
    then
	[ -f "$sdir/xvnc0.socket" ] && n=0
	while [ -f "$sdir/xvnc$n.socket" ]
	do
	    n=$(($n+1))
	done
    else
	rm -f $sdir/xvnc*.socket $sdir/xvnc*@.service
	n=1
    fi
fi

echo ""
echo "Enter VNC resolutions as desired in the format WIDTHxHEIGHT (e.g. 1920x1080)"
echo "Each will be assigned a successive VNC port"
echo "Press Enter by itself to finish"
echo ""
while [ 0 ]
do
    echo -n "VNC resolution for VNC$n: "
    res=$(read ans; echo $ans)
    [ "$res" == "" ] && break
    echo "% Creating VNC socket/service pair for VNC$n with resolution $res"
    port=$((5900+$n))
    cat > $sdir/xvnc$n.socket <<EOF
[Unit]
Description=XVNC Server $n

[Socket]
ListenStream=$port
Accept=yes

[Install]
WantedBy=sockets.target
EOF
    cat > $sdir/xvnc$n@.service <<EOF
[Unit]
Description=XVNC Per-Connection Daemon $n

[Service]
ExecStart=-$vncsrv $extrasw -inetd -query 127.0.0.1 -geometry $res -pn -once
StandardInput=socket
StandardOutput=socket
StandardError=journal
EOF
    n=$(($n+1))
done

if [ $notroot -eq 1 ]
then
    echo "systemctl daemon-reload"
    systemctl daemon-reload
    if askyn "Enable and start VNC sockets"
    then
	for (( i=1; i<$n; i++))
	do
	    echo "systemctl stop xvnc$i.socket"
	    systemctl stop xvnc$i.socket
	    echo "systemctl enable --now xvnc$i.socket"
	    systemctl enable --now xvnc$i.socket
	done
    else
	echo "% You must 'sudo systemctl enable' each of the xvnc sockets to enable them"
    fi
fi