major run-virt restructure, only vmware plugin tested!

15 files changed, 727 insertions, 649 deletions

diff --git a/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/download_vm_metadata.inc b/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/download_vm_metadata.inc
index 974a5626..818896fc 100644
--- a/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/download_vm_metadata.inc
+++ b/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/download_vm_metadata.inc
@@ -1,32 +1,46 @@
 ########################################################
 # Include: Detect, whether runvirt runs in legacy mode #
 ########################################################
-
+## Functions ##
 # Legacy mode: As runvirt has been before.
 # New mode: uuid in xml _and_ vmx given via http.
+download_metadata() {
+	# Sanity checks
+	if ! check_dep wget; then
+		writelog "Could not find 'wget' in PATH: $PATH"
+		EXIT_TYPE="internal" EXIT_REASON="Fehlendes Dienstprogramm 'wget'!" cleanexit 1
+	fi
 
-writelog "Detecting current/legacy mode ..."
+	if ! isset SLX_VMCHOOSER_BASE_URL; then
+		writelog "SLX_VMCHOOSER_BASE_URL is not set! Was /opt/openslx/config sourced?"
+		EXIT_TYPE="internal" EXIT_REASON="Keine URL zur Schnittstelle des bwLehrpool-Satelliten gefunden!" cleanexit 1
+	fi
 
-declare -rg TMPCONFIG="$TMPDIR/vmconfig.tmp"
+	writelog "Detecting current/legacy mode..."	
+	declare -rg TMPCONFIG="$TMPDIR/vmconfig.tmp"
 
-# Assume legacy mode by default, only trigger "current" mode if everything else below worked
-LEGACY=yes
-if [ -z "$IMGUUID" ]; then	# Keine uuid: Abbruch, Legacy
-	writelog "Could not extract a uuid param from ${xmlfile}. Triggering legacy mode."
-else
-	# Now getting template file:
-	if ! wget -T 6 -O "$TMPCONFIG" "${SLX_VMCHOOSER_BASE_URL}/lecture/${IMGUUID}" 2>/dev/null >&2; then
-		writelog "wget ${SLX_VMCHOOSER_BASE_URL}/lecture/${IMGUUID}. Triggering legacy mode."
-	else
-		writelog "wget ${SLX_VMCHOOSER_BASE_URL}/lecture/${IMGUUID} successful."
-		if [ ! -s "$TMPCONFIG" ]; then
-			writelog "Server sent zero byte virtual machine description file. Triggering legacy mode."
+	if wget -T 6 -O "$TMPCONFIG" "${SLX_VMCHOOSER_BASE_URL}/lecture/${IMGUUID}" 2>/dev/null >&2; then
+		writelog "Downloaded VM description from '${SLX_VMCHOOSER_BASE_URL}/lecture/${IMGUUID}' successfully."
+		if [ -s "$TMPCONFIG" ]; then
+			# Downloaded a non-zero VM description file, all good
+			return 0
 		else
-			writelog "Triggering current (non-legacy) mode."
-			LEGACY=		# everything worked - clear legacy mode variable (so we use the "current" mode)
+			writelog "Server sent zero byte virtual machine description file. Triggering legacy mode."
 		fi
 	fi
-fi
 
-readonly LEGACY
+	# Seems we are in legacy mode, which is no longer supported. Warn user and exit
+	EXIT_TYPE="user" EXIT_REASON="
+Die gewählte VM ist eine 'Legacy VM', für die unvollständige
+Metadaten auf dem bwLehrpool-Server hinterlegt sind. Diese
+werden nicht mehr unterstützt. Um diese VM weiterhin nutzen
+zu können, muss sie mittels der bwLehrpool-Suite heruntergeladen,
+einmal gebootet, und wieder hochgeladen werden.
+(Bei der Gelegenheit könnten z.B. auch gleich anfallende Updates
+eingespielt werden.)
+" cleanexit 1
+}
+
+## Main ##
+call_post_source download_metadata
 
diff --git a/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/get_xml_file_variables.inc b/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/get_xml_file_variables.inc
index fdacc69c..a6543c76 100644
--- a/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/get_xml_file_variables.inc
+++ b/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/get_xml_file_variables.inc
@@ -1,63 +1,69 @@
 ############################################
 # Include: Get needed values from XML file #
 ############################################
-
-writelog "Parsing XML..."
-
-declare -rg VMSTORE_PATH=/mnt/vmstore
-
-get_xml () {
-	xmlextract "//settings/eintrag/${1}/@param" "${xmlfile}"
+## Functions ##
+parse_xml() {
+	# Sanity checks
+	if ! check_dep get_xml; then
+		writelog "Could not find 'get_xml'"
+		EXIT_TYPE="internal" EXIT_REASON="Keine XML-Unterstützung!" cleanexit 1
+	fi
+
+	writelog "Parsing XML..."
+	declare -rg VMSTORE_PATH=/mnt/vmstore
+	declare -rg IMGUUID=$(get_xml "uuid")
+	if isempty IMGUUID; then
+		writelog "Error parsing XML: No value for 'uuid'."
+		EXIT_TYPE="user" EXIT_REASON="Konnte keine ID für das ausgewählte Image ermitteln!" cleanexit 1
+	fi
+
+	# Relative / Absolute path to image
+	declare -rg SRC_IMG_RELATIVE=$(get_xml "image_name")
+	declare -g SRC_IMG_ABSOLUTE=$(get_xml "image_path")
+
+	if isempty SRC_IMG_ABSOLUTE SRC_IMG_RELATIVE; then
+		writelog "Error parsing XML: Neither relative nor absolute path for image found!"
+		EXIT_TYPE="user" EXIT_REASON="Konnte kein Pfad zur ausgewählten virtuellen Maschine ermitteln!" cleanexit 1
+	fi
+
+	if isempty SRC_IMG_ABSOLUTE && [ "${SRC_IMG_ABSOLUTE:0:1}" != "/" ]; then
+		writelog "Error parsing XML: Parsed value for absolute path doesn't start with '/': '$SRC_IMG_ABSOLUTE'"
+		EXIT_TYPE="user" EXIT_REASON="Ungültiger asboluter Pfad zur virtuellen Maschine!" cleanexit 1 
+	fi
+
+	notempty SRC_IMG_ABSOLUTE || SRC_IMG_ABSOLUTE="${VMSTORE_PATH}/${SRC_IMG_RELATIVE}"
+	readonly SRC_IMG_ABSOLUTE
+
+	declare -rg IMG_BASENAME=$(basename "$SRC_IMG_ABSOLUTE")
+
+	VM_DISPLAYNAME=$(get_xml "short_description")
+	notempty VM_DISPLAYNAME || VM_DISPLAYNAME="${IMG_BASENAME}"
+	readonly VM_DISPLAYNAME
+	
+	# Define VM_CLEANNAME since VM_DISPLAYNAME can be long and contain weird characters
+	declare -rg VM_CLEANNAME=$(echo "${VM_DISPLAYNAME:0:32}" | sed -r 's/[^0-9a-zA-Z_-\.]+/_/g')
+	
+	# image is for the following virtual machine
+	declare -rg PLUGIN_ID=$(get_xml "virtualmachine")
+	if isempty PLUGIN_ID; then
+       		writelog "Error parsing XML: No value for 'virtualmachine'."
+		EXIT_TYPE="user" EXIT_REASON="Konnte kein Virtualisierer für das ausgewählte Image ermitteln." cleanexit 1
+	fi
+	
+	# Extracting OS type (VM_OS_TYPE) from xml file. We don't care here whether VM_OS_TYPE is empty, as then 
+	# it will yield the default entries later on.
+	declare -g VM_OS_TYPE=$(get_xml "os")
+
+	# Print summary to log
+	writelog "\tVirtualization plugin:  $PLUGIN_ID"
+	writelog "\tVM filename:            $IMG_BASENAME"
+	writelog "\tVM UUID:                $IMGUUID"
+	writelog "\tVM name:                $VM_DISPLAYNAME"
+	writelog "\tVM short name:          $VM_CLEANNAME"
+	writelog "\tVM OS:                  $VM_OS_TYPE"
+	writelog "Done parsing XML."
+	return 0
 }
 
-IMGUUID=$(get_xml "uuid")
-
-# # Name of the virt image
-SRC_IMG_ABSOLUTE=$(get_xml "image_path")
-SRC_IMG_RELATIVE=$(get_xml "image_name")
-
-if [ -z "${SRC_IMG_ABSOLUTE}${SRC_IMG_RELATIVE}" ]; then
-	writelog "Neither relative nor absolute path for image found in xml"
-	cleanexit 1
-fi
-
-if [ -n "$SRC_IMG_ABSOLUTE" ] && [ "${SRC_IMG_ABSOLUTE:0:1}" != "/" ]; then
-	writelog "Error parsing XML for absolute image path: given value doesn't start with '/': '$SRC_IMG_ABSOLUTE'"
-	cleanexit 1
-fi
-
-if [ -z "$SRC_IMG_ABSOLUTE" ]; then
-	SRC_IMG_ABSOLUTE="${VMSTORE_PATH}/${SRC_IMG_RELATIVE}"
-fi
-
-IMG_BASENAME=$(basename "$SRC_IMG_ABSOLUTE")
-writelog "Virtual image file name: $IMG_BASENAME"
-
-VM_DISPLAYNAME=$(get_xml "short_description")
-[ -z "$VM_DISPLAYNAME" ] && VM_DISPLAYNAME="${IMG_BASENAME}"
-
-# Define VM_NAME_CLEAN since VM_DISPLAYNAME can be long and contain weird characters
-VM_NAME_CLEAN=$(echo "${VM_DISPLAYNAME:0:32}" | sed -r 's/[^0-9a-zA-Z_-\.]+/_/g')
-
-# image is for the following virtual machine
-PLUGIN_ID=$(grep -o 'virtualmachine param=.*"' "${xmlfile}" \
-	| sed -e "s/&.*;/; /g" | awk -F '"' '{print $2}')
-
-# Extracting OS type (VM_OS_TYPE) from xml file. We don't care here whether VM_OS_TYPE is empty, as then 
-# it will yield the default entries later on.
-VM_OS_TYPE=$(get_xml "os")
-
-readonly IMGUUID
-readonly SRC_IMG_ABSOLUTE SRC_IMG_RELATIVE
-readonly IMG_BASENAME
-readonly VM_DISPLAYNAME VM_NAME_CLEAN
-readonly PLUGIN_ID
-readonly VM_OS_TYPE
-
-writelog "VM UUID:                $IMGUUID"
-writelog "Virtualization plugin:  $PLUGIN_ID"
-writelog "VM name:                $VM_DISPLAYNAME"
-writelog "VM short name:          $VM_NAME_CLEAN"
-writelog "VM OS:                  $VM_OS_TYPE"
-writelog "Done parsing XML."
-
+## MAIN ##
+call_post_source parse_xml
diff --git a/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/init_core.inc b/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/init_core.inc
new file mode 100644
index 00000000..8e83811c
--- /dev/null
+++ b/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/init_core.inc
@@ -0,0 +1,18 @@
+################################################
+# Include: Sets core variables and directories #
+################################################
+# Global variables needed for the core functionality
+declare -rg VMCHOOSER_DIR="/opt/openslx/vmchooser"
+declare -rg VMCHOOSER_CONF_DIR="$VMCHOOSER_DIR/config"
+declare -rg USER="$(whoami)"
+declare -rg LOGFILE="/var/log/openslx/run-virt.${USER}.$$.log"
+declare -rg TMPDIR="/tmp/virt/${USER}/$$"
+
+# Create temporary directory for current invocation
+if check_dep mkdir && ! mkdir -p "$TMPDIR"; then
+	writelog "Could not create temporary directory '$TMPDIR' for session"
+	EXIT_TYPE="internal" EXIT_REASON="Konnte kein Arbeitsverzeichnis für die VM-Sitzung anlegen." cleanexit 1
+fi
+
+# Get a unique VM_ID for the current invocation
+get_vm_id
diff --git a/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/load_configs.inc b/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/load_configs.inc
new file mode 100644
index 00000000..bd205816
--- /dev/null
+++ b/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/load_configs.inc
@@ -0,0 +1,19 @@
+###################################################
+# Include: Declaration of run-virt core variables #
+###################################################
+## Functions ##
+load_configs() {
+	writelog "Loading configs..."
+
+	# Include general configuration from vmchooser
+	$(safesource --exit "$VMCHOOSER_CONF_DIR/vmchooser.conf")
+
+	# Load general virtualization information
+	$(safesource --exit "$VMCHOOSER_CONF_DIR/virtualization.conf")
+	
+	# Load general openslx config
+	$(safesource --exit "/opt/openslx/config")
+}
+
+## MAIN ##
+call_post_source load_configs
diff --git a/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/set_runvirt_hardware_variables.inc b/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/set_runvirt_hardware_variables.inc
index 508c9efe..5fb14806 100644
--- a/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/set_runvirt_hardware_variables.inc
+++ b/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/set_runvirt_hardware_variables.inc
@@ -1,113 +1,124 @@
 ###########################################
 # Include: Set hardware related variables #
 ###########################################
+# New way of handling MAC address prefixes to support
+# nested and concurrent run-virt invocations.
+# Using a list of predefined MAC prefixes to use for VMs,
+# check if the host's MAC address prefix is in that list.
+# If not, use the first prefix in the list. If it is
+# use the next prefix in the list. If the host's prefix
+# is the last in the list, use the first one again.
+# This way we support up to 10 nested/concurrent VMs.
+# Use: 00:FF:00 for firtual machines ;)
+declare -gA MAC_PREFIXES
+for i in {0..9}; do
+	# make an associate array, it will make our life easier later
+	MAC_PREFIXES["00:FF:0$i"]="$i"
+done
 
-get_vm_id() {
-	local script=${BASH_SOURCE[-1]}
-	[ -z "$script" ] && script="$0"
-	if [ -n "$script" ]; then
-		script=$(readlink -f "$script")
-		if [ -n "$script" ] && [ -s "$script" ]; then
-			#bingo
-			VM_ID=$(ps ax | grep -F "$script" | grep -v 'grep' | grep -o -- "${script}.*\$" | sort -u | wc -l)
-			if [ "$VM_ID" -gt 0 ]; then
-				[ "${#VM_ID}" -eq 1 ] && VM_ID="0${VM_ID}"
-				[ "${#VM_ID}" -gt 2 ] && VM_ID="${VM_ID:0:2}"
-				[ "${#VM_ID}" -eq 2 ] && return
-			fi
-		fi
-	fi
-	# fallback: take last two digits of current pid...
-	VM_ID=$(expr substr $$ $(expr ${#$} - 1) 2)
-	[ "${#VM_ID}" -eq 1 ] && VM_ID="0${VM_ID}"
-}
-
-get_vm_id
-
-# Make sure cpu_cores is not empty
-cpu_cores=${cpu_cores:-"1"}
-
-# Amount of memory for the VM. Be generous if diff is written to HDD
-if mount | grep -q '^/dev/sd.*on.*/tmp'; then
-	reserve=20
-	min=768
-	max=1800
-else
-	reserve=65
-	min=768
-	max=8192
-fi
 
-# Calculate absulute amount of RAM that should stay available to the host
-reserve="$(( ( totalmem * reserve ) / 100 ))"
-# Respect some upper and lower bounds for the host amount
-[ "$reserve" -lt "$min" ] && reserve="$min"
-[ "$reserve" -gt "$max" ] && reserve="$max"
+## Functions ##
+# Sets the VM's hostname to the original hostname prefixed with a fixed string and its ID 
+set_virt_hostname() {
+	declare -rg HOSTNAME="virt${VM_ID}-$(hostname)"
+	writelog "\tVM Hostname:\t\t$HOSTNAME"
+}
+set_virt_cpu() {
+	# Make sure CPU_CORES is not empty
+	declare -g CPU_CORES=${CPU_CORES:-"1"}
+}
+# Derives the amount of memory allocated to the VM from the
+# host's total memory (previously determined by systemd-run_virt_env)
+set_virt_memory() {
+	# Make sure we have a VM_ID and HOST_MEM_TOTAL (read from virtualization.conf)
+	if isempty HOST_MEM_TOTAL; then
+		writelog "HOST_MEM_TOTAL is empty! Was '$VMCHOOSER_CONF_DIR/virtualization.conf' sourced?"
+		EXIT_TYPE="internal" EXIT_REASON="Konnte die Größe des Arbeitsspeichers nicht ermitteln!" cleanexit 1
+	fi
 
-# Get a result which can be divided by 4
-mem="$(( ( ( totalmem - reserve ) / 4 ) * 4 ))"
-if [ -n "$mainvirtmem" ]; then
-	forcemem="$(( mainvirtmem / 4 * 4 ))"
-	mem="$forcemem"
-fi
-hostmem="$(( totalmem - mem ))"
+	# Amount of memory for the VM. Be generous if diff is written to HDD
+	local min=768
+	local reserve max
+	if mount | grep -q '^/dev/sd.*on.*/tmp'; then
+		reserve=20
+		max=1800
+	else
+		reserve=65
+		max=8192
+	fi
 
-# Fill in VMID
-macaddrsuffix=$(echo "$macaddrsuffix" | sed "s/%VMID%/${VM_ID}/")
+	# Calculate absulute amount of RAM that should stay available to the host
+	local reserve="$(( ( HOST_MEM_TOTAL * reserve ) / 100 ))"
+	# Respect some upper and lower bounds for the host amount
+	[ "$reserve" -lt "$min" ] && reserve="$min"
+	[ "$reserve" -gt "$max" ] && reserve="$max"
+
+	# Get a result which can be divided by 4
+	declare -g VM_MEM="$(( ( ( HOST_MEM_TOTAL - reserve ) / 4 ) * 4 ))"
+	declare -g HOST_MEM_REMAINING="$(( HOST_MEM_TOTAL - VM_MEM ))"
+	# NOTE: removed old code that evaluated 'mainvirtmem'
+	# as it did nothing and we don't know what the idea was... 
+}
 
-if ! echo "$macaddrprefix" | grep -q -E '^[0-9A-F]{2}:[0-9A-F]{2}:[0-9A-F]{2}$'; then
-	slxlog "virt-mac" "Could not properly generate mac address prefix (got $macaddrprefix)"
-fi
-if ! echo "$macaddrsuffix" | grep -q -E '^[0-9A-F]{2}:[0-9A-F]{2}:[0-9A-F]{2}$'; then
-	slxlog "virt-mac" "Could not properly generate mac address suffix (got $macaddrsuffix)"
-fi
-macaddr="$macaddrprefix:$macaddrsuffix"
+# New way to generate MAC addresses:
+# MAC_PREFIXES is a statically declared list of prefixes which
+# can be used for VMs. To support nested VMs, we just look for
+# the MAC prefix of the host and if it is present in the list,
+# we just take the next one in the list. Currently support up to 10.
+# If none are found, we just take the first prefix.
+# Suffix template is taken from /opt/openslx/vmchooser/config/virtualization.conf
+# and will have the VMID inserted as first byte.
+set_virt_mac() {
+	# First, determine prefix of the host's MAC address
+	isset HOSTMACADDR || writelog "Host's MAC address was not defined in ${VMCHOOSER_CONF_DIR}/virtualizer.conf"
+	local HOST_MAC_PREFIX=$(echo "$HOSTMACADDR" | tr '[a-z]' '[A-Z]' | grep -o -E '^[0-9A-F]{2}:[0-9A-F]{2}:[0-9A-F]{2}')
+	unset MACADDRPREFIX
+	if notempty HOST_MAC_PREFIX && notempty MAC_PREFIXES[${HOST_MAC_PREFIX}]; then
+		# the host's prefix was in our list, so use the next one in the list
+		local -i HOST_MAC_PREFIX_INDEX="${MAC_PREFIXES[${HOST_MAC_PREFIX}]}" # this will be at least 0
+		# increment if its between 0 and 8
+		if [[ $HOST_MAC_PREFIX_INDEX =~ ^[0-8]$ ]]; then
+			declare -g MACADDRPREFIX="${HOST_MAC_PREFIX%?}$(( ++HOST_MAC_PREFIX_INDEX ))"
+		fi
+	fi
+	# host's mac prefix could not be determined (practically this should never happen)
+	# or the prefix is not in our mac address list or we reached the end of the list.
+	# Either way, use first mac prefix in the list
+	notempty MACADDRPREFIX || declare -g MACADDRPREFIX="$(echo ${!MAC_PREFIXES[@]} | awk '{print $1}')"
+
+	# Fill in VM_ID
+	local MACADDRSUFFIX=${MACADDRSUFFIX//%VMID%/"${VM_ID}"}
+	
+	if ! echo "$MACADDRPREFIX" | grep -q -E '^[0-9A-F]{2}:[0-9A-F]{2}:[0-9A-F]{2}$'; then
+		slxlog "virt-mac" "Could not properly generate mac address prefix (got $MACADDRPREFIX)"
+	fi
+	if ! echo "$MACADDRSUFFIX" | grep -q -E '^[0-9A-F]{2}:[0-9A-F]{2}:[0-9A-F]{2}$'; then
+		slxlog "virt-mac" "Could not properly generate mac address suffix (got $MACADDRSUFFIX)"
+	fi
+	declare -g VM_MAC_ADDR="$MACADDRPREFIX:$MACADDRSUFFIX"
+}
 
 # Virtual fd/cd/dvd and drive devices, floppy b: for configuration
-# if $floppy_0 from virtualization.conf set then fdtest="TRUE"
-fdtest=${floppy_0:+"TRUE"}
-# if $fdtest not set floppy0="FALSE", else "TRUE"
-floppy0=${fdtest:-"FALSE"}
-# if $cdrom_0 from virtualization.conf set then cdtest="TRUE"
-cdtest=${cdrom_0:+"TRUE"}
-# if $cdtest not set cdrom0="FALSE", else "TRUE"
-cdrom0=${cdtest:-"FALSE"}
-# if $cdrom_1 from virtualization.conf set then cdtest="TRUE"
-cdtest=${cdrom_1:+"TRUE"}
-# if $cdtest not set cdrom1="FALSE", else "TRUE"
-cdrom1=${cdtest:-"FALSE"}
-
-# Dynamically detect serial ports here instead of at boot time
-# (virtualization.conf), since USB serial ports get quite common
-# and might not be plugged in at boot time yet
-serial_0=
-#for port in $(awk '{ if ($1 ~ /^[0-9]+:/ && $2 != "uart:unknown") print "/dev/ttyS" sub(/:\$/, "", $1) }' /proc/tty/driver/serial); do
-for port in $serial_ports /dev/ttyUSB*; do
-	[ -c "$port" ] || continue
-	serial_0="$port"
-	break
-done
-
-parallel_0=
-for port in /dev/parport*; do
-	[ -c "$port" ] || continue
-	parallel_0="$port"
-	break
-done
-
-# RDP/VNC port (59001 - 59099)
-remotedesktopport="590${VM_ID}"
-
-# Add rw share for home dir
-homesharepath="${HOME}/PERSISTENT"
-homesharename="home"
-
-# Add common share
-commonsharepath="${HOME}/SHARE"
-commonsharename="share"
-
-# Set hostname: using original hostname and adding string
-hostname="virt-$(hostname)"
+# NOTE: This uses bash's variable expansion magic to set
+# CDROM/FLOPPY variables evaluated later by the virtualizers...
+# If the variables in virtualization.conf is set, "TRUE" is assigned,
+# "FALSE" otherwise.
+check_optical_drives() {
+	local TESTVAR=${FLOPPY_0:+"TRUE"}
+	declare -rg FLOPPY0=${TESTVAR:-"FALSE"}
+
+	TESTVAR=${CDROM_0:+"TRUE"}
+	declare -rg CDROM0=${TESTVAR:-"FALSE"}
+
+	TESTVAR=${CDROM_1:+"TRUE"}
+	declare -rg CDROM1=${TESTVAR:-"FALSE"}
+}
 
-writelog "\tVM Hostname:\t\t$hostname"
+## MAIN ##
+call_post_source \
+	set_virt_cpu \
+	set_virt_memory \
+	set_virt_mac \
+	set_virt_hostname \
+	check_optical_drives
 
diff --git a/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/set_runvirt_variables.inc b/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/set_runvirt_variables.inc
deleted file mode 100644
index cd9a573a..00000000
--- a/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/set_runvirt_variables.inc
+++ /dev/null
@@ -1,26 +0,0 @@
-######################################################
-# Include: Declaration of run-virt default variables #
-######################################################
-
-VMCHOOSER_DIR="/opt/openslx/vmchooser"
-VMCHOOSER_CONF_DIR="$VMCHOOSER_DIR/config"
-USER="$(whoami)"
-LOGFILE="/var/log/openslx/run-virt.${USER}.$$.log"
-TMPDIR="/tmp/virt/${USER}/$$"
-
-readonly VMCHOOSER_DIR VMCHOOSER_CONF_DIR LOGFILE TMPDIR USER
-
-# include general configuration from vmchooser
-[ -f "$VMCHOOSER_CONF_DIR/vmchooser.conf" ] && . "$VMCHOOSER_CONF_DIR/vmchooser.conf"
-# load general virtualization information
-[ -f "$VMCHOOSER_CONF_DIR/virtualization.conf" ] && . "$VMCHOOSER_CONF_DIR/virtualization.conf"
-# Load general openslx config
-[ -f "/opt/openslx/config" ] && . "/opt/openslx/config"
-# Create temp dir
-if ! mkdir -p "$TMPDIR"; then
-	slxlog "virt-tmpdir" "Could not create temporary directory '$TMPDIR' for session"
-	error_user "Konnte kein temporäres Arbeitsverzeichnis für die VM-Sitzung anlegen. Ein Computer-Neustart könnte das Problem lösen."
-	cleanexit 1
-	exit 1
-fi
-
diff --git a/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/setup_firewall.inc b/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/setup_firewall.inc
deleted file mode 100644
index f0820ed7..00000000
--- a/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/setup_firewall.inc
+++ /dev/null
@@ -1,12 +0,0 @@
-
-setup_firewall () {
-	local LOGF="${TMPDIR}/firewall.log"
-	local RET
-	[ "$DISPLAY" = ":0" ] || return 0 # For now, to avoid conflicts, we only do this on display :0
-	slxfwtool "$IMGUUID" > "$LOGF" 2>&1
-	RET=$?
-	if [ "$RET" != "0" ]; then
-		slxlog "runvirt-firewall" "Error setting up firewall rules for lecture $IMGUUID (Exit code $RET)" "$LOGF"
-	fi
-	return 0
-}
diff --git a/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/setup_image_access.inc b/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/setup_image_access.inc
index 4240d9ca..a41c1055 100644
--- a/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/setup_image_access.inc
+++ b/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/setup_image_access.inc
@@ -1,7 +1,6 @@
 ###########################################################
 # Include: Setup dnbd for image access, nfs/cifs fallback #
 ###########################################################
-
 # This will currently make sure that the variable
 # VM_DISKFILE_RO is set which will contain the
 # absolute path to the disk image to use for the vm
@@ -14,85 +13,112 @@
 # indicate to the virt plugin that it doesn't need to
 # handle creating a temporary CoW layer itself.
 
-writelog "Setting up disk access for virtualizer/emulator ..."
 
-# Try to use dnbd3 to access the image
-unset VM_DISKFILE_RO
-unset dnbd3_fuse_mount_point
+# Helper to cleanup the image mounted with dnbd3-fuse
+cleanup_dnbd3() {
+	if ! isset DNBD3_MOUNT_POINT; then
+		writelog "'DNBD3_MOUNT_POINT' is not set! Aborting DNBD3 cleanup."
+		return 1
+	fi
+	# try to umount it now
+	for timeout in 1 1 1 FAIL; do
+		fusermount -u "${DNBD3_MOUNT_POINT}" && break
+		writelog "dnbd3 still busy...."
+		[ "$timeout" = "FAIL" ] && break
+		sleep "$timeout"
+	done
+}
 
 setup_dnbd3 () {
 	# Mount path for images mounted with dnbd3-fuse
-	dnbd3_fuse_mount_point="$TMPDIR/dnbd3fuse.mnt"
-	mkdir -p "${dnbd3_fuse_mount_point}"
+	declare -rg DNBD3_MOUNT_POINT="${TMPDIR}/dnbd3fuse.mnt"
+	mkdir -p "${DNBD3_MOUNT_POINT}"
 	# start dnbd3-fuse in subshell
-	local dnbd3_tmplog="$TMPDIR/dnbd3fuse.log"
-	local dnbd3_exitflag="$TMPDIR/dnbd3exit$RANDOM"
-	local TIMEOUT vm_revision
-	rm -f -- "$dnbd3_exitflag"
+	local DNBD3_TMPLOG="${TMPDIR}/dnbd3fuse.log"
+	local DNBD3_EXITFLAG="${TMPDIR}/dnbd3exit$RANDOM"
+	local TIMEOUT VM_DISKFILE_REVISION
+	rm -f -- "${DNBD3_EXITFLAG}"
 	(
-		dnbd3-fuse -f -o allow_other,max_readahead=262144 -h "$SLX_DNBD3_SERVERS" -i "${SRC_IMG_RELATIVE}" "${dnbd3_fuse_mount_point}" > "$dnbd3_tmplog" 2>&1
+		dnbd3-fuse -f -o allow_other,max_readahead=262144 -h "${SLX_DNBD3_SERVERS}" -i "${SRC_IMG_RELATIVE}" "${DNBD3_MOUNT_POINT}" > "${DNBD3_TMPLOG}" 2>&1
 		RET=$?
-		touch "$dnbd3_exitflag"
+		touch "${DNBD3_EXITFLAG}"
 		if [ "$RET" != "0" ]; then
 			writelog "dnbd3-fuse stopped working (Exit code $RET)"
-			slxlog "virt-dnbd3-fuse" "dnbd3-fuse stopped/refused serving '${SRC_IMG_RELATIVE}' from '${SLX_DNBD3_SERVERS}' with error code: $RET" "${dnbd3_tmplog}"
+			slxlog "virt-dnbd3-fuse" "dnbd3-fuse stopped/refused serving '${SRC_IMG_RELATIVE}' from '${SLX_DNBD3_SERVERS}' with error code: $RET" "${DNBD3_TMPLOG}"
 		fi
 	) &
 	# give it a bit of time
 	usleep 250000
 	# check if we have the image
 	for TIMEOUT in 0.5 1 1 OUT; do
-		if [ -r "${dnbd3_fuse_mount_point}/img" ]; then
-			vm_revision="$(grep -m 1 "^Revision:" "${dnbd3_fuse_mount_point}/status" | cut  -d" " -f2)"
-			VM_DISKFILE_RO="${dnbd3_fuse_mount_point}/img"
-			writelog "DNBD3: $SRC_IMG_RELATIVE on $VM_DISKFILE_RO with rid $vm_revision"
+		if [ -r "${DNBD3_MOUNT_POINT}/img" ]; then
+			VM_DISKFILE_REVISION="$(grep -m 1 "^Revision:" "${DNBD3_MOUNT_POINT}/status" | cut  -d" " -f2)"
+			VM_DISKFILE_RO="${DNBD3_MOUNT_POINT}/img"
+			writelog "DNBD3: ${SRC_IMG_RELATIVE} on ${VM_DISKFILE_RO} with rid ${VM_DISKFILE_REVISION}"
+			add_cleanup "cleanup_dnbd3"
 			break
 		fi
-		[ "$TIMEOUT" = "OUT" -o -e "$dnbd3_exitflag" ] && break
+		[ "$TIMEOUT" = "OUT" -o -e "$DNBD3_EXITFLAG" ] && break
 		sleep "$TIMEOUT"
 	done
 
-	if [ -z "$VM_DISKFILE_RO" ]; then
-		slxlog "virt-dnbd3" "No dnbd3 server for ${SRC_IMG_RELATIVE} found, trying NFS/CIFS..." "$dnbd3_tmplog"
+	if isempty VM_DISKFILE_RO; then
+		slxlog "virt-dnbd3" "No dnbd3 server for ${SRC_IMG_RELATIVE} found, trying NFS/CIFS..." "$DNBD3_TMPLOG"
 		writelog "No working dnbd3 server found :-("
+	else
+		readonly VM_DISKFILE_RO
 	fi
 }
 
-# See if we should setup dnbd3 image access at all
-if ! which dnbd3-fuse; then
-	writelog "Can't use dnbd3 as dnbd3-fuse binary is not in PATH"
-elif [ -z "$SRC_IMG_RELATIVE" ]; then
-	writelog "Can't use dnbd3 as SRC_IMG_RELATIVE is not set"
-elif [ -z "$SLX_DNBD3_SERVERS" ] || [ "x$SLX_VM_DNBD3" != "xyes" ]; then
-	writelog "Can't use dnbd3 as no servers are given in config, or SLX_VM_DNBD3 is not set to yes"
-else
-	setup_dnbd3
-fi
-
-# VM_DISKFILE_RO will be empty if dnbd3 is not used or failed to connect.
-# Let's try to fall back to NFS/CIFS via file system
-if [ -z "$VM_DISKFILE_RO" ]; then
+setup_fallback() {
 	# Maybe we're reading a dnbd3 directory with RIDs encoded into the filename - use latest one
-	rid_suffix=$(ls -1 "${SRC_IMG_ABSOLUTE}.r"* | grep -E -o '\.r[0-9]+$' | grep -o -E '[0-9]+$' | sort -n | tail -n 1)
-	if [ -n "$rid_suffix" ]; then
+	unset VM_DISKFILE_REVISION
+	local VM_DISKFILE_REVISION=$(ls -1 "${SRC_IMG_ABSOLUTE}.r"* | grep -E -o '\.r[0-9]+$' | grep -o -E '[0-9]+$' | sort -n | tail -n 1)
+	if notempty VM_DISKFILE_REVISION; then
 		# found
-		VM_DISKFILE_RO="${SRC_IMG_ABSOLUTE}.r${rid_suffix}"
-	elif [ -e "$SRC_IMG_ABSOLUTE" ]; then
+		VM_DISKFILE_RO="${SRC_IMG_ABSOLUTE}.r${VM_DISKFILE_REVISION}"
+	elif [ -e "${SRC_IMG_ABSOLUTE}" ]; then
 		# try name we got from xml in the first place
-		VM_DISKFILE_RO="$SRC_IMG_ABSOLUTE"
+		VM_DISKFILE_RO="${SRC_IMG_ABSOLUTE}"
 	fi
-fi
-
-# Check if virtual machine container file exists
-if [ -z "$VM_DISKFILE_RO" ] || ! [ -e "${VM_DISKFILE_RO}" ]; then
-	slxlog "virt-image-missing" "VM image $VM_DISKFILE_RO not found!"
-	writelog "Virtual machine image ${VM_DISKFILE_RO} not found!"
-	error_user "Das Image für die gewählte Virtuelle Maschine konnte nicht gefunden werden.
-Versuchen Sie zunächst, den Computer komplett neu zu starten. Sollte das Problem bestehen bleiben, wenden Sie sich bitte an den Support."
-	cleanexit 1
-fi
+	readonly VM_DISKFILE_RO
+}
 
-readonly VM_DISKFILE_RO
 
-writelog "Disk file to use: $VM_DISKFILE_RO"
+## MAIN PART / Sanity checks ##
+setup_image_access() {
+	writelog "Setting up virtual hard disk access for virtualizer/emulator ..."
+	
+	unset VM_DISKFILE_RO
+	declare -g VM_DISKFILE_RO
+	
+	# See if we should setup dnbd3 image access at all
+	if ! check_dep dnbd3-fuse fusermount; then
+		writelog "\tCan't use dnbd3 as dnbd3-fuse/fusermount binaries are not in PATH"
+	elif ! isset SRC_IMG_RELATIVE; then
+		writelog "\tCan't use dnbd3 as SRC_IMG_RELATIVE is not set"
+	elif ! isset SLX_DNBD3_SERVERS || [ "x${SLX_VM_DNBD3}}" != "xyes" ]; then
+		writelog "\tCan't use dnbd3 as no servers are given in config, or SLX_VM_DNBD3 is not set to yes"
+	else
+		# register setup_dnbd3 as start hook after sourcing this include
+		writelog "Trying image access via DNBD3..."
+		setup_dnbd3
+	fi
+	
+	# VM_DISKFILE_RO will be empty if dnbd3 is not used or failed to connect.
+	if isempty VM_DISKFILE_RO; then
+		# try to fallback to access the image via NFS/CIFS filesystem
+		writelog "Trying fallback image access via NFS/CIFS..."
+		setup_fallback
+	fi
+	
+	# Check if we finally found a valid, readable container
+	if isempty VM_DISKFILE_RO || [ ! -r "${VM_DISKFILE_RO}" ]; then
+		writelog "Virtual machine image ${VM_DISKFILE_RO} not found!"
+		EXIT_TYPE="user" EXIT_REASON="Konnte virtuelle Festplatte des gewählten Image nicht finden!" cleanexit 1
+	fi
+	
+	writelog "\tVM disk file:\t\t${VM_DISKFILE_RO}"
+}
 
+call_post_source setup_image_access
diff --git a/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/setup_printer_lpd.inc b/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/setup_printer_lpd.inc
deleted file mode 100644
index 2fb9310a..00000000
--- a/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/setup_printer_lpd.inc
+++ /dev/null
@@ -1,46 +0,0 @@
-#####################################
-# Include: Setup printer daemon LPD #
-#####################################
-
-QUEUE="STANDARD" # This has to match the queue you configured in your VM
-SPOOLDIR=
-
-### Disabled: 100megs is not enough, some jobs are HUGE, try to use temp which should be on disk
-## Try using user's tmpfs home first, as it gets wiped on logout
-#if [ -n "${HOME}" ] && [ -w "${HOME}" ]; then
-#       SPOOLDIR="${HOME}/.spool"
-#       mkdir -p "${SPOOLDIR}/${QUEUE}"
-#fi
-# If failed, try to fall back to /tmp
-
-if [ -z "${SPOOLDIR}" ] || [ ! -w "${SPOOLDIR}/${QUEUE}" ]; then
-	SPOOLDIR="${TMPDIR}/printergui-${RANDOM}"
-	rm -rf -- "${SPOOLDIR}"
-	if ! mkdir -p "${SPOOLDIR}/${QUEUE}"; then
-		slxlog "virt-spooldir" "Could not create spool directory ($SPOOLDIR) for $USER - printing will not work!"
-		# TODO: Warn user
-	fi
-	chmod 0700 "${SPOOLDIR}/${QUEUE}"
-fi
-
-# Start the lpdaemon listening on the given port
-# TODO: externalize with something like runvirt.d (other parts might benefit from that too)
-tcpsvd -E 192.168.101.1 5515 \
-	lpd "$SPOOLDIR" \
-	ash -c "/opt/openslx/scripts/run-virt_print '${USER}' \"${SPOOLDIR}/${QUEUE}/\$DATAFILE\"" &
-
-# PID to kill the process
-PID_LPD="$!"
-
-{
-	sleep 2
-	# Check if tcpsvd is running. Do this a little delayed so we do not check
-	# immediately after trying to spawn it, as this could result in
-	# success even if it's not really working.
-
-	if ! kill -0 "$PID_LPD"; then
-		slxlog "virt-lpd" "Could not start tcpsvd/lpd for virtual machine session"
-		notify_user "Durcksystem" "Das Drucksystem konnte nicht initialisiert werden. Druckfunktion nicht verfügbar."
-	fi
-} &
-
diff --git a/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/setup_sound.inc b/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/setup_sound.inc
deleted file mode 100644
index c6cece3d..00000000
--- a/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/setup_sound.inc
+++ /dev/null
@@ -1,79 +0,0 @@
-#!/bin/bash
-# ^-- Add shebang even though it's sourced so vim highlights bash specific features properly
-########################
-# Include: Setup sound #
-########################
-
-writelog "Starting sound setup ..."
-
-unset VOL
-if [ -r "/run/hwinfo" ] && source "/run/hwinfo"; then
-	# On startup, the volume of Master, PCM, Speaker, etc. will be set to 100%
-	# Some hardware with builtin speakers might be a bit too loud then, so you can
-	# define an exception table here. Array key is "Manufacturer//Model"
-	declare -A VOLUME_EXCEPTIONS
-	VOLUME_EXCEPTIONS["Hewlett-Packard//HP Compaq 8200 Elite CMT PC"]="85%" # This is bwPC3
-	# Read
-	VOL=${VOLUME_EXCEPTIONS["${HW_MANUF}//${HW_MODEL}"]}
-fi
-
-# Default to maximum volume
-if [ -z "$VOL" ]; then
-	VOL="100%"
-fi
-
-if true; then
-	# detecting which card is to be used
-	writelog --quiet "Detecting which sound card to use ..."
-	PROC="/proc/asound/cards"
-	if [ ! -r "$PROC" ]; then
-		writelog --quiet "'${PROC}' not found or not readable."
-		SOUND_CARD_INDEX=0
-		SOUND_CARD_COUNT=1
-	else
-		# Try to filter HDMI cards first
-		SOUND_CARD_INDEX=$(grep -v -i 'HDMI' "${PROC}" | grep -E -o '^[[:space:]]{0,2}[0-9]+[[:space:]]+' | head -n 1)
-		# If empty, try again with all
-		[ -z "${SOUND_CARD_INDEX}" ] && SOUND_CARD_INDEX=$(cat "${PROC}" | grep -E -o '^[[:space:]]{0,2}[0-9]+[[:space:]]+' | head -n 1)
-		if [ -z "${SOUND_CARD_INDEX}" ]; then
-			writelog --quiet "No sound card found."
-			SOUND_CARD_INDEX=0
-		fi
-		SOUND_CARD_COUNT=$(grep -E '^[[:space:]]{0,2}[0-9]+[[:space:]]+' "${PROC}" | wc -l)
-	fi
-	
-	SOUND_CARD_INDEX="$(grep -E -o '[0-9]+' <<<$SOUND_CARD_INDEX)"
-	writelog --quiet "Detected sound card index is: $SOUND_CARD_INDEX"
-	writelog --quiet "Sound card count: $SOUND_CARD_COUNT"
-	
-	# Adjust sound volume (playback)... Random mixer names we have encountered during testing
-	writelog --quiet "Setting up volume..."
-	(
-		amixer -q -c "$SOUND_CARD_INDEX" sset 'Master' "$VOL" unmute
-		amixer -q -c "$SOUND_CARD_INDEX" sset 'PCM' "100%" unmute
-		amixer -q -c "$SOUND_CARD_INDEX" sset 'CD' "100%" unmute
-		amixer -q -c "$SOUND_CARD_INDEX" sset 'Headphone' "100%" unmute
-		amixer -q -c "$SOUND_CARD_INDEX" sset 'Front' "100%" unmute
-		amixer -q -c "$SOUND_CARD_INDEX" sset 'Speaker' "100%" unmute
-		# Recording. It seems that (most) devices need the volume set to 0, so you
-		# don't hear your own mic input, but should be unmuted. Also on some cards,
-		# you need to set the cap option on the mic you want to use, while other cards
-		# will just ignore that option.
-		# Plus, most cards have a Capture mixer, which needs to be set to cap too, and
-		# have its volume turned up. (There'll probably be some cards that need yet
-		# another setup, but this works for now on 4 tested cards)
-		amixer -q -c "$SOUND_CARD_INDEX" sset 'Rear Mic Boost' "50%" cap unmute
-		amixer -q -c "$SOUND_CARD_INDEX" sset 'Rear Mic' "0%" cap unmute
-		amixer -q -c "$SOUND_CARD_INDEX" sset 'Front Mic Boost' "50%" cap unmute
-		amixer -q -c "$SOUND_CARD_INDEX" sset 'Front Mic' "0%" cap unmute
-		amixer -q -c "$SOUND_CARD_INDEX" sset 'Mic Boost' "50%" cap unmute
-		amixer -q -c "$SOUND_CARD_INDEX" sset 'Mic' "0%" cap unmute
-		amixer -q -c "$SOUND_CARD_INDEX" sset 'Capture' "100%" cap unmute
-		amixer -q -c "$SOUND_CARD_INDEX" sset 'Input Source' 'Mic'
-		amixer -q -c "$SOUND_CARD_INDEX" sset 'Input Source' 'Front Mic' # Let's hope nobody uses rear mic...
-		# fix random static noise when starting vmplayer when module snd_pcsp (not pcspkr) is loaded
-		amixer -q -c pcsp sset Master "0%" mute 2>/dev/null >&2
-	) 2>&1 | grep -v 'amixer: Unable to find'
-	writelog --quiet "Done setting up volume."
-fi >> "${LOGFILE}" 2>&1 # Don't pipe here since it would spawn a subshell so all variable modifications would be lost
-
diff --git a/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/setup_virtual_floppy.inc b/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/setup_virtual_floppy.inc
deleted file mode 100644
index d9ae052c..00000000
--- a/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/setup_virtual_floppy.inc
+++ /dev/null
@@ -1,101 +0,0 @@
-#!/bin/bash
-##############################################
-# Include: Setup virtual floppy for drive b: #
-##############################################
-
-declare -rg FLOPPYIMG="${TMPDIR}/floppy.img"
-declare -rg TMPHOME="${HOME}"
-declare -rg RUNSCRIPT="${TMPDIR}/runscript.tmp"
-
-wget -T 6 -O "${RUNSCRIPT}" "${SLX_VMCHOOSER_BASE_URL}/lecture/${IMGUUID}/runscript" > /dev/null &
-WGET=$!
-
-dd "if=/dev/zero" "of=${FLOPPYIMG}" count=1440 bs=1024
-chmod 0600 "${FLOPPYIMG}"
-mkfs.fat "${FLOPPYIMG}" || mkfs.vfat "${FLOPPYIMG}" || mkdosfs "${FLOPPYIMG}"
-
-# Create file with resolution information etc.
-. "/opt/openslx/inc/shares"
-if [ -z "$SHARE_REMAP_MODE" ]; then
-	SHARE_REMAP_MODE_INI="0"
-	SHARE_REMAP_MODE="3"
-else
-	SHARE_REMAP_MODE_INI="$SHARE_REMAP_MODE"
-fi
-[ -z "$SHARE_CREATE_MISSING_REMAP" ] && SHARE_CREATE_MISSING_REMAP="1"
-declare -rg RESOLUTION=$(xrandr | grep -o -E 'connected\s*(primary)?\s*[0-9]+x[0-9]+\+0\+0' \
-	| grep -o -E -m1 '[0-9]+x[0-9]+')
-
-# Legacy: HOSTRES.TXT
-cat > "${TMPDIR}/HOSTRES.TXT" <<-HIER
-${RESOLUTION}
-HIER
-
-# Create file for network shares to mount
-declare -rg SHARES="${TMPDIR}/shares.dat"
-touch "${SHARES}"
-chmod 0600 "${SHARES}"
-if ! pwdaemon --query "${TMPHOME}/.pwsocket" > "${SHARES}"; then
-	slxlog "virt-pwdaemon" "Could not start pwdaemon"
-else
-	sed -i 's/^/192.168.101.1\t/' "${SHARES}" # TODO: Depending on nettype (in case we have != nat some day)
-	if [ "${SHARE_REMAP_MODE}" = 1 -o "${SHARE_REMAP_MODE}" = 2 ] && [ -e "${TMPHOME}/.home" ]; then
-		NETHOME=$(cat "${TMPHOME}/.home")
-		[ -z "$SHARE_HOME_DRIVE" ] && SHARE_HOME_DRIVE="H:"
-		# Tab between items, so spaces can be used!
-		echo "${NETHOME}	${SHARE_HOME_DRIVE}	Home-Verzeichnis" >> "${SHARES}"
-	fi
-	for VAR in ${!SHARE_LINE_*}; do
-		echo "${!VAR}" >> "${SHARES}"
-	done
-fi
-
-wait "$WGET"
-
-# Check downloaded runscript, handle extension marker
-EXT=
-if [ -s "$RUNSCRIPT" ]; then
-	EXT=$(head -n 1 "$RUNSCRIPT" | grep -o -i '^EXT=.*$' | cut -d '=' -f 2-)
-	[ -n "$EXT" ] && [ "x${EXT:0:1}" != "x." ] && EXT=".$EXT"
-fi
-
-# Write info file
-UNAME=
-[ -s "${HOME}/.account" ] && UNAME=$(cat "${HOME}/.account")
-[ -z "${UNAME}" ] && UNAME=$(whoami)
-cat > "${TMPDIR}/openslx.ini" <<-HIER
-[openslx]
-username=${UNAME}
-resolution=${RESOLUTION}
-createMissingRemap=${SHARE_CREATE_MISSING_REMAP}
-remapMode=${SHARE_REMAP_MODE_INI}
-homeDrive=${SHARE_HOME_DRIVE}
-scriptExt=${EXT}
-
-[remap]
-documents=${SHARE_DOCUMENTS}
-downloads=${SHARE_DOWNLOADS}
-desktop=${SHARE_DESKTOP}
-media=${SHARE_MEDIA}
-other=${SHARE_OTHER}
-HIER
-
-# Copy all them there filez into floppy image
-mcopy -i "${FLOPPYIMG}" "${TMPDIR}/openslx.ini" "${TMPDIR}/HOSTRES.TXT" "${SHARES}" "::/"
-mcopy -i "${FLOPPYIMG}" "$VMCHOOSER_DIR/data/openslx.exe" "::/"
-# Copy guest configuration (with added information) config.xml to be accessed
-# via virtual floppy
-mcopy -i "${FLOPPYIMG}" "$xmlfile" "::/config.xml"
-
-# Copying linux directory:
-mcopy -s -i "${FLOPPYIMG}" "$VMCHOOSER_DIR/data/linux" "::/"
-
-# User supplied runscript
-if [ -n "$EXT" ]; then
-	sed -i '1d' "${RUNSCRIPT}"
-	mcopy -i "${FLOPPYIMG}" "${RUNSCRIPT}" "::/runscript${EXT}"
-fi
-
-rm -f -- "${SHARES}" "${TMPDIR}/openslx.ini" "${TMPDIR}/HOSTRES.TXT"
-unset SHARES VAR NETHOME UNAME
-
diff --git a/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/setup_vm_hypervisor.inc b/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/setup_vm_hypervisor.inc
index 7709a85d..80b7dbb9 100644
--- a/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/setup_vm_hypervisor.inc
+++ b/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/setup_vm_hypervisor.inc
@@ -1,34 +1,18 @@
 ##########################################################################
 # Include: Setup virtual machine hypervisor via vm-specific include file #
 ##########################################################################
-
-# Get all virtual machine specific stuff from the respective include file
-if [ ! -e "$VMCHOOSER_DIR/$PLUGIN_ID/run-virt.include" ] ; then
-	slxlog "virt-plugin-missing" "Could not find run-virt.include for $PLUGIN_ID ($VMCHOOSER_DIR/$PLUGIN_ID/run-virt.include)"
-	writelog "Failed because of missing ${PLUGIN_ID} plugin."
-	error_user "Konnte den Virtualisierer '$PLUGIN_ID' nicht finden. Starten der Virtuellen Maschine fehlgeschlagen.
-	Starten Sie den Computer neu und wenden Sie sich an den Support, wenn das Problem weiterhin besteht."
-	cleanexit 1
-fi
-
-self="${PLUGIN_ID}"
-
-if ! bash -n "$VMCHOOSER_DIR/$PLUGIN_ID/run-virt.include"; then
-	slxlog "virt-plugin-syntax" "run-virt.include for $PLUGIN_ID contains syntax errors (bash -n run-virt.include failed)"
-	writelog "Erroneous run-virt.include for $PLUGIN_ID (syntax check)"
-	error_user "Das Start-Script für den Virtualisierer '$PLUGIN_ID' ist fehlerhaft.
-	Starten Sie den Computer neu und wenden Sie sich an den Support, wenn das Problem weiterhin besteht."
-	cleanexit 1
-fi
-
-setup_vm_commandline () {
-	# Now including the hypervisor specific include file:
-	if ! source "$VMCHOOSER_DIR/$PLUGIN_ID/run-virt.include"; then
-		slxlog "virt-plugin-error" "run-virt.include for $PLUGIN_ID could not be sourced properly."
-		writelog "Erroneous run-virt.include for ${PLUGIN_ID}? Source returned != 0"
-		error_user "Das Start-Script für den Virtualisierer '$PLUGIN_ID' hat einen fehlercode zurückgegeben.
-		Starten Sie den Computer neu, falls es beim Ausführen der VM zu Problemen kommt
-		und wenden Sie sich an den Support, wenn das Problem weiterhin besteht."
+## Functions ##
+setup_vm_commandline() {
+	# Sanity checks
+	if ! isset PLUGIN_ID; then
+		writelog "Sanity check failed: PLUGIN_ID is not set."
+		EXIT_TYPE="internal" EXIT_REASON="Konnte kein Virtualisierer für das gewählte Image ermitteln!" cleanexit 1
+	fi
+	if ! $(safesource "$VMCHOOSER_DIR/plugins/$PLUGIN_ID/run-virt.include"); then
+		# safesource logs errors on its own
+		EXIT_TYPE="internal" EXIT_REASON="Konnte Virtualisierungsplugin '$PLUGIN_ID' nicht initialisieren!" cleanexit 1
 	fi
 }
 
+## Main ##
+call_post_source setup_vm_commandline
diff --git a/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/start_windowmanager.inc b/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/start_windowmanager.inc
index da43f341..37d88ab4 100644
--- a/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/start_windowmanager.inc
+++ b/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/start_windowmanager.inc
@@ -1,27 +1,42 @@
 ####################################################
 # Include: Start windowmanager for easier handling #
 ####################################################
-
+## Functions ##
 # Some problems may arise with windows opening in background when
 # using eg. vmware without a window manager.
-
-FOUND_WM=
-for dm in openbox kwin xfwm4 metacity blackbox twm fvwm2 ; do
-	if which $dm >/dev/null 2>&1 ; then
-		if [ "$dm" = "fvwm2" ] ; then
-			echo "EdgeScroll 0 0" > ${redodir}/fvwm
-			writelog "Starting fvwm2."
-			fvwm2 -f ${redodir}/fvwm >/dev/null 2>&1 &
-		else
-			writelog "Starting ${dm}."
-			$dm >/dev/null 2>&1 &
+start_wm() {
+	# Sanity checks
+	unset RUNVIRT_DM
+	for DM in openbox kwin xfwm4 metacity blackbox twm fvwm2 ; do
+		if type "${DM}" >/dev/null 2>&1 ; then
+			declare -rg RUNVIRT_DM="${DM}"
+			break
 		fi
-		FOUND_WM=1
-		break
+	done
+	if ! isset RUNVIRT_DM; then
+		# not fatal, so do not exit but report via slxlog
+		slxlog "runvirt-wm" "Could not find any window manager to use!"
+		notify_user "Konnte keinen Window Manager finden. (Das ist schlecht!)"
+		return 1
+	fi
+
+	# start RUNVIRT_DM determined above
+	writelog "Starting ${RUNVIRT_DM}."
+	if [ "${RUNVIRT_DM}" = "fvwm2" ]; then
+		# fvwm2 is not even in the minilinux, so this might be obsolete...
+		echo "EdgeScroll 0 0" > ${TMPDIR}/fvwm
+		fvwm2 -f ${TMPDIR}/fvwm >/dev/null 2>&1 &
+	else
+		${RUNVIRT_DM} >/dev/null 2>&1 &
+	fi
+	local RUNVIRT_DM_PID="$$"
+	if ! kill -0 ${RUNVIRT_DM_PID} ; then
+		# not fatal, just warn user
+		notify_user "$RUNVIRT_VM stoppte unerwartet."
+		return 1
 	fi
-done
+	return 0
+}
 
-if [ -z "$FOUND_WM" ]; then
-	slxlog "virt-windowmanager" "Could not find any window manager to use!"
-	notify_user "Konnte keinen Window Manager finden. (Das ist schlecht!)"
-fi
+## MAIN ##
+call_post_source start_wm
diff --git a/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/usb_detector.inc b/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/usb_detector.inc
deleted file mode 100644
index a2d442e4..00000000
--- a/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/usb_detector.inc
+++ /dev/null
@@ -1,77 +0,0 @@
-# Helper function that will scan /dev/bus/usb for devices matching specific classes
-# and then output the corresponding device ids. This can be used for selective
-# handover of devices to a virtual machine
-
-declare -rg PASSTHROUGH_USB_DEVICES="2 0:5 0:6 0:7 0:14 0:16 0:17 239"
-
-# $1: expression to fill with device information.
-#     valid placeholders are:
-#     %VENDOR%  - device vendor id
-#     %PRODUCT% - device product id
-# $2-n: device classes to include in output
-get_usb_devices_int() {
-	[ -z "$TMPDIR" ] && TMPDIR="/tmp"
-	local EXP=$1
-	shift
-	if [ -z "$EXP" ]; then
-		writelog --quiet "No ouput expression template passed to get_usb_devices"
-		cleanexit 1
-	fi
-	if [ $# -eq 0 ]; then
-		writelog --quiet "No device classes given to get_usb_devices"
-		cleanexit 1
-	fi
-	local MATCH=';'
-	while [ $# -gt 0 ]; do
-		MATCH+="$1;"
-		[[ "$1" != *:* ]] && MATCH+="0:$1;"
-		shift
-	done
-	local dev=
-	local key value trailing
-	trailing=
-	local tmp="${TMPDIR}/lsusb.$$.$RANDOM"
-	for dev in /dev/bus/usb/*/*; do
-		if ! lsusb -D "$dev" > "$tmp" 2>/dev/null; then
-			writelog --quiet "Cannot lsusb $dev"
-			continue
-		fi
-		local DC=
-		local OK=
-		local VENDOR=
-		local PRODUCT=
-		while read -r key value trailing || [ -n "$key" ]; do
-			if [[ "$key" == "idVendor" ]]; then
-				[[ "$value" == 0x* ]] && VENDOR="${value:2}"
-			elif [[ "$key" == "idProduct" ]]; then
-				[[ "$value" == 0x* ]] && PRODUCT="${value:2}"
-			elif [ -z "$DC" ]; then
-				# No bDeviceClass seen yet
-				if [[ "$key" == "bDeviceClass" ]]; then
-					DC="$value"
-					[[ "$MATCH" == *";${DC};"* ]] && OK=yo
-				fi
-			else
-				# #DeviceClass is generic, look at sub class
-				if [[ "$key" == "bInterfaceClass" ]]; then
-					[[ "$MATCH" == *";${DC}:${value};"* ]] && OK=yo
-				fi
-			fi
-			if [ -n "$OK" -a -n "$VENDOR" -a -n "$PRODUCT" ]; then
-				echo "$EXP" | sed "s/%VENDOR%/${VENDOR}/g;s/%PRODUCT%/${PRODUCT}/g"
-				break
-			fi
-		done < "$tmp"
-	done
-	rm -f -- "$tmp"
-}
-
-get_usb_devices() {
-	if which lsusb 2>/dev/null >&2 && lsusb --help 2>&1 | grep -q -- '-D' 2>/dev/null; then
-		[ $# -eq 1 ] && set -- "$1" $PASSTHROUGH_USB_DEVICES # no quotes here!
-		get_usb_devices_int "$@" | sort -u
-	else
-		writelog --quiet "Cannot scan usb bus: lsusb not found or doesn't support -D"
-	fi
-}
-
diff --git a/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/vmchooser_runvirt_functions.inc b/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/vmchooser_runvirt_functions.inc
index ca475da0..d09f6a75 100644
--- a/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/vmchooser_runvirt_functions.inc
+++ b/core/modules/run-virt/data/opt/openslx/vmchooser/run-virt-includes/vmchooser_runvirt_functions.inc
@@ -1,8 +1,32 @@
 #######################################################
 # Include: Set functions needed by vmchooser-run_virt #
 #######################################################
+## Assigns an ID to the currently starting VM to support
+# multiple instances running simultaneously.
+# Note that VM_ID will always have two digits.
+get_vm_id() {
+	local script=${BASH_SOURCE[-1]}
+	[ -z "$script" ] && script="$0"
+	if [ -n "$script" ]; then
+		script=$(readlink -f "$script")
+		if [ -n "$script" ] && [ -s "$script" ]; then
+			#bingo
+			declare -g VM_ID=$(ps ax | grep -F "$script" | grep -v 'grep' | grep -o -- "${script}.*\$" | sort -u | wc -l)
+			if [ "$VM_ID" -gt 0 ]; then
+				[ "${#VM_ID}" -eq 1 ] && VM_ID="0${VM_ID}"
+				[ "${#VM_ID}" -gt 2 ] && VM_ID="${VM_ID:0:2}"
+				[ "${#VM_ID}" -eq 2 ] && readonly VM_ID && return
+			fi
+		fi
+	fi
+	# fallback: take last two digits of current pid...
+	VM_ID=$(expr substr $$ $(expr ${#$} - 1) 2)
+	[ "${#VM_ID}" -eq 1 ] && VM_ID="0${VM_ID}"
+	readonly VM_ID
+}
 
-# function to write to stdout and logfile
+################# LOGGING FUNCTIONS ##################
+# Helper function to write to stdout and logfile
 writelog() {
 	local DATE=$(date +%Y-%m-%d-%H-%M-%S)
 	# write to stdout?
@@ -12,9 +36,11 @@ writelog() {
 		echo -e "$DATE: $@"
 	fi
 	# log into file
-	echo -e "$DATE: $@" >> "${LOGFILE}"
+	echo -e "$DATE: ${SLX_DEBUG:+(${FUNCNAME[1]}) }$@" >> "${LOGFILE}"
 }
 
+# Helper function to notify the user.
+# This directly returns and do not wait for a user confirmation.
 notify_user() {
 	local TOPIC="$1"
 	shift
@@ -22,6 +48,8 @@ notify_user() {
 	writelog "Notify: **${TOPIC}**: $*"
 }
 
+# Helper to display an error message box to the user.
+# Only returns when the user dismisses the message.
 error_user() {
 	local TOPIC="$1"
 	shift
@@ -37,47 +65,246 @@ $*"
 		BODY="$TOPIC"
 	fi
 	# Zenity should yield the nicest result
-	zenity --error --title "$TITLE" --text "$BODY" && return
+	# TODO the title is only set as the window name,
+	# which cannot be seen without a window manager
+	zenity --error --title "$TITLE" --text "$BODY"
+	local RET=$?
+	[ $RET -le 1 ] && return
 	# QnD abuse printergui for error message as it's blocking
 	/opt/openslx/cups/printergui --error "$MSG" && return
 	# printergui might not exist, try fallback here
-	# unfortunately, i can only think of notify+sleep right now
+	# unfortunately, I can only think of notify+sleep right now
 	notify-send -u critical "$TITLE" "$BODY"
 	sleep 10
 }
 
-# Clean exit will be called at the end of vmchooser-run_virt
+################## CLEANUP FUNCTIONS ##################
+# Registers functions to be called when cleanexit is called.
+# Only accepts functions that were not previously registered.
+# This kinda detects when a cleanup function was overriden,
+# or at least that something is fishy.
+declare -ag CLEANUP_TASKS
+add_cleanup() {
+	[ $# -lt 1 ] && writelog "'${FUNCNAME[0]}' needs at least one argument! $# given." && return
+	# check if the given function name is already used
+	while [ $# -ne 0 ]; do
+		if array_contains CLEANUP_TASKS "$1"; then
+			writelog "Cleanup function '$1' already registered! Are there multiple definitions of this function?"
+			writelog "This might suggest that a previously defined cleanup function was overriden!"
+			return 1
+		fi
+		CLEANUP_TASKS+=("$1")
+		shift
+	done
+	return 0
+}
+# This function will be called at the end of vmchooser-run_virt
+# or upon critical errors during the runtime.
+# It will call the cleanup functions registered through 'add_cleanup'
+# and clean TMPDIR if appropriate. Further, it will evaluate and
+# process the EXIT_{TYPE,REASON} variables that hold information
+# on why we are about to exit.
+#
+# EXIT_TYPE should be either:
+#	- 'internal' for critical internal errors, this will
+#	   automatically send the logfile via slxlog.
+#	- 'user' for errors related to the user's choice
+# Others could be thought of like 'external' for failures
+# with remote services (e.g. slx apis, external image repo, ...)
+#
+# EXIT_REASON should contain a user-friendly message to print to the user.
 cleanexit() {
+	writelog "Cleanexit '$1' triggered by '${BASH_SOURCE[1]}:${FUNCNAME[1]}'"
 	sleep 1
-	# Ummount dnbd3-fuse
-	if [ -n "$dnbd3_fuse_mount_point" ] && [ -e "$dnbd3_fuse_mount_point/img" ]; then
-		for timeout in 1 1 1 FAIL; do
-			fusermount -u "$dnbd3_fuse_mount_point" && break
-			writelog "dnbd3 still busy...."
-			[ "$timeout" = "FAIL" ] && break
-			sleep "$timeout"
-		done
-	fi
-	# Kill LPD
-	[ -n "${PID_LPD}" ] && kill "${PID_LPD}"
+	while isset CLEANUP_TASKS; do
+		local TASK=${CLEANUP_TASKS[-1]}
+		unset -v CLEANUP_TASKS[-1]
+		if ! is_function $TASK; then
+			writelog "Registered cleanup function '$TASK' is not a function. This should not be..."
+			continue
+		fi
+		if ! ${TASK}; then
+			writelog "Failed to run cleanup function '$TASK'! Exit code: $RET"
+		fi
+	done
 
 	# If we're not in debug mode, remove all temporary files
-	if [ -n "${TMPDIR}" -a -z "$SLX_DEBUG" ]; then
+	if notempty SLX_DEBUG && isset TMPDIR; then
 		rm -rf -- "${TMPDIR}"
 	fi
 
-	[ $# -gt 0 ] && exit "$1"
-	exit 129 # No exit code was given :/
-}
+	# Now see if we need to do the catch all error stuff
+	# no exit code given, return 129
+	[ $# -eq 0 ] && exit 129
+	# if 0 given, exit 0
+	[ "x$1" = "x0" ] && exit 0
 
-rv_clean_string() {
-	if [ "$#" -ge 1 ]; then
-		echo "$@" | tr '[A-Z]' '[a-z]' | tr -d -c '[a-z0-9\-]'
+	# given exit code is set and not 0, handle the error now
+	# now evaluate the EXIT_{TYPE,REASON} variables and generate error title/text
+	local ERR_TITLE ERR_TEXT ERR_FOOTER
+	# default error footer
+	ERR_FOOTER="Versuchen Sie den Computer neuzustarten und falls das Problem bestehen bleibt, kontaktieren Sie den Support."
+	if notempty EXIT_TYPE; then
+		case "${EXIT_TYPE}" in
+			user)
+				ERR_TITLE="Auswahlfehler"
+				ERR_FOOTER="Beim Start Ihrer Veranstaltung sind Fehler aufgetretten. Versuchen Sie es mit einer anderen Veranstaltung."
+				;;
+			internal)
+				ERR_TITLE="Interner Fehler"
+				;;
+			*)
+				ERR_TITLE="Unbekannter Fehler"
+				writelog "Unknown EXIT_TYPE: '${EXIT_TYPE}'."
+				;;
+		esac
+	fi	
+	if notempty EXIT_REASON; then
+		ERR_TEXT="${EXIT_REASON}"
 	else
-		tr '[A-Z]' '[a-z]' | tr -d -c '[a-z0-9\-]'
+		# this should never happen if EXIT_REASON is properly
+		# used when calling cleanexit !
+		ERR_TEXT="Unbekannter Fehler"
+	fi
+
+	# first send the logfile (in case the user does not close the error before using magic keys e.g.)
+	# for any other error types besides 'user'.
+	[ "x${EXIT_TYPE}" != "xuser" ] && \
+		slxlog "runvirt-exit-${EXIT_TYPE}" "Critical error happened in '${BASH_SOURCE[1]}:${FUNCNAME[1]}', see logs." "${LOGFILE}"
+
+	# finally display the error
+	error_user "${ERR_TITLE}" "
+${ERR_TEXT}
+
+${ERR_FOOTER}
+"
+	writelog "All done. Exiting."
+	exit "$1"
+}
+
+################# SOURCING FUNCTIONS #################
+# Wrapped 'source' that first checks for existence and 
+# syntax before actually sourcing the given file.
+# The option '--exit' triggers cleanexit upon syntax errors.
+# Without it, it returns 0 when tests passed, 1 otherwise.
+# Usage:
+#	safesource [--exit] <files>
+safesource() {
+	declare -i EXIT_ON_FAILURE=0
+	[ "x$1" = "x--exit" ] && EXIT_ON_FAILURE=1 && shift
+	while [ $# -gt 0 ]; do
+		# sanitze filename just to be sure as it is part of the eval coming later
+		# alphanumeric and - _ . should be enough for common file naming scheme
+		if [[ ! "$1" =~ ^[a-zA-Z0-9./_-]+$ ]]; then
+	       		writelog "'$1' is a weird filename to source! Ignoring."
+			return 1
+		fi
+		local FILE="$1"
+		shift
+		bash -n "${FILE}"
+		local -i RET=$?
+		if [ $RET -ne 0 ]; then
+			case $RET in
+				1) writelog --quiet "Bad file to source: ${FILE}" ;;
+				2) writelog --quiet "Bad syntax: ${FILE}" ;;
+				126) writelog --quiet "Could not access: ${FILE}" ;;
+				127) writelog --quiet "File not found: ${FILE}" ;;
+				*) writelog --quiet "Syntax check (bash -n) returned unknown error code '${RET}' for: ${FILE}" ;;
+			esac
+			if [ $EXIT_ON_FAILURE -eq 1 ]; then
+		       		echo "eval EXIT_REASON=\"internal:source:${FILE}\" cleanexit 1 ;"
+			else
+				echo "eval writelog \"Could not safesource '${FILE}'.\" ;"
+			fi
+			return 1
+		fi
+		echo "eval source ${FILE} ;"
+		echo "run_post_source ${FILE} ;"
+
+	done
+	return 0 
+}
+
+# Registers functions to be called after sourcing an include.
+# Includes should only define functions and register them
+# to be called after successfully sourcing.
+declare -Ag RUN_POST_SOURCE
+call_post_source() {
+	while [ $# -gt 0 ]; do
+		if ! is_function "$1"; then
+			writelog "Tried to register a non-function: '$1'"
+			continue
+		fi
+		if notempty BASH_SOURCE[1]; then
+			RUN_POST_SOURCE[${BASH_SOURCE[1]}]+="$1 "
+			shift
+		else
+			writelog "Could not determine the sourced file calling ${FUNCNAME[0]}"
+		fi
+	done
+}
+# Helper called after sourcing the file via safesource. It just calls the
+# functions in the same order they were registered.
+run_post_source() {
+	[ $# -ne 1 ] && writelog "'${FUNCNAME[0]}' expects one argument only! $# given." && return 1
+	for TASK in ${RUN_POST_SOURCE["${1}"]}; do
+		# sanity checks
+		if ! is_function $TASK; then
+			writelog "\tRegistered function '$TASK' is not a function!"
+			return 1 # TODO maybe even cleanexit here as this seems very bad...
+		fi
+		# remove from stack before running it
+		RUN_POST_SOURCE["${1}"]="${RUN_POST_SOURCE[${1//${TASK}\ /\ }]}"
+		${TASK}
+		local -i RET=$?
+		if [ $RET -ne 0 ]; then
+			writelog "\tFailed to run post source '${TASK}' (Exit code: $RET)"
+			return $RET
+		fi
+	done
+	return 0
+}
+
+################# FEATURE FUNCTIONS ##################
+# Helper to register feature handlers, read run-virt.d/README
+declare -Ag FEATURE_HANDLERS
+reg_feature_handler() {
+	if [ $# -ne 2 ]; then
+		writelog "'${FUNCNAME[0]}' expects 2 arguments! $# given."
+		return 1
+	fi
+	if notempty FEATURE_HANDLERS["$1"]; then
+		writelog "'${BASH_SOURCE[1]}' tried to overwrite feat handler '$1'! Ignoring."
+		# maybe allow overwritting?
+		return 1
 	fi
+	if ! is_function "$2"; then
+		writelog "'${BASH_SOURCE[1]}' tried to register a non-function as feat handler!"
+		writelog "\t'$2' is a '$(type -t $2 2>&1)'."
+		return 1
+	fi
+	# all good, save it
+	FEATURE_HANDLERS["$1"]="$2"
+	return 0
 }
 
+
+################### XML FUNCTIONS ####################
+# Extract given xpath from given xml file
+# e.g.: xmlextract '//node/nestednode/@attribute' "$file"
+# @param
+# @return Plain text, UTF-8
+xmlextract() {
+	xmlstarlet sel -T -E utf-8 -t -v "$1" "$2"
+}
+
+# Wrapper for convenience
+get_xml () {
+	xmlextract "//settings/eintrag/${1}/@param" "${XML_FILE}"
+}
+
+
+################## HELPER FUNCTIONS ##################
 # Check if the given variables are set (empty or not)
 isset() {
 	while [ $# -gt 0 ]; do
@@ -96,12 +323,111 @@ notempty() {
 	return 0
 }
 
-##
-# Extract given xpath from given xml file
-# e.g.: xmlextract '//node/nestednode/@attribute' "$file"
-# @param
-# @return Plain text, UTF-8
-xmlextract() {
-	xmlstarlet sel -T -E utf-8 -t -v "$1" "$2"
+# Convenience function
+isempty() {
+	! notempty $@
+}
+
+# Helper to test if given arguments are declared as functions
+is_function() {
+	while [ $# -gt 0 ]; do
+		local TYPE="$(type -t "$1" 2>/dev/null)"
+		if [ "x${TYPE}" != "xfunction" ]; then
+			writelog "'$1' not a function but a '${TYPE}'."
+			return 1
+		fi
+		shift
+	done
+	return 0
 }
 
+# Helper to test if given arguments are declared as arrays
+is_array() {
+	
+	# -ne 1 ] && writelog "is_array: Expects 1 argument! $# given." && return 1
+	while [ $# -gt 0 ]; do
+		local ARRAY_DEF="$(declare -p ${1} 2>/dev/null)"
+		if [[ ! "${ARRAY_DEF}" =~ "declare -a" ]] && [[ ! "${ARRAY_DEF}" =~ "declare -A" ]]; then
+			return 1
+		fi
+		shift
+	done
+	return 0
+}
+
+# Helper to test is the given array contains given value
+# Usage:
+#	array_contains ARRAY_TO_TEST <values...>
+array_contains() {
+	if [ $# -lt 2 ]; then
+		writelog "${FUNCNAME[0]}: Expects at least 2 arguments, $# given."
+		return 1
+	fi
+	# is $1 even defined?
+	local ARRAY_DEF="$(declare -p $1 2>/dev/null)"
+	if isempty ARRAY_DEF; then
+		writelog "${FUNCNAME[0]}: '$1' not defined!"
+		return 1
+	fi
+	local ARRAY_NAME="$1"
+	shift
+
+	# sanity check on $ARRAY_DEF being either indexed or associative array
+	if ! is_array "${ARRAY_NAME}"; then
+		writelog "${FUNCNAME[0]}: '${ARRAY_NAME}' not an array! Declared as:\t${ARRAY_DEF}"
+		return 1
+	fi
+
+	# now test if array contains the given values in $2+
+	while [ $# -gt 0 ]; do
+		# check if ARRAY_DEF contains '"<value>"'
+		if [[ ! "${ARRAY_DEF}" =~ '="'${1}'"'[^\]]+ ]]; then 
+			writelog "${FUNCNAME[0]}: '${1}' not in '${ARRAY_NAME}'"
+			return 1
+		fi
+		shift
+	done
+	return 0
+}
+
+# Helper to check if the given arguments are valid command names.
+# This uses 'type -t' thus supports notably binaries, functions
+# and aliases (might need these one day).
+# By default, only 0 is returned if all arguments are found.
+# Use '--oneof' to return 0 if any one of the arguments are found.
+check_dep() {
+	[ $# -lt 1 ] && return 1
+	unset ONEOF
+	if [ "x$1" = "x--oneof" ]; then
+		local ONEOF="1"
+		shift
+	fi
+	while [ $# -gt 0 ]; do
+		if ! type -t "$1" >/dev/null 2>&1 ; then
+			writelog "Dependency check failed! Could not find '$1'."
+			isset ONEOF || return 1
+		else
+			isset ONEOF && return 0
+		fi
+		shift
+	done
+	isset ONEOF && return 1 || return 0 
+}
+
+
+
+# TODO: This is only used once in the whole script:
+# to cleanup the os string stored in the xml
+# Since the rework of this script, the os strings come from
+# the satellite server which already gives us a sanitized string
+# thus this function might not be needed anymore, as calling it on
+# new gen os strings effectively does nothing.
+# Removes any non-alphanumerical and non-hyphen chars
+# from the given parameters.
+clean_string() {
+	if [ "$#" -ge 1 ]; then
+		echo "$@" | tr '[A-Z]' '[a-z]' | tr -d -c '[a-z0-9\-]'
+	else
+		tr '[A-Z]' '[a-z]' | tr -d -c '[a-z0-9\-]'
+	fi
+}