#!/bin/bash

# set -x

# logger "openslx vm_runtime: Started."

DISTRIBUTION=$(lsb_release -is | tr '[A-Z]' '[a-z]' | sed -r 's/[^a-z0-9]//g;s/project$//g;s/scientificsl$/scientific/g')
VERSION=$(lsb_release -rs)
SCRIPTDIR=/mnt/diskmount/linux/
RESOLUTIONSCRIPT="${SCRIPTDIR}"/resolution
SHARESCRIPT="${SCRIPTDIR}"/mnt_shares
UMOUNTSCRIPT="${SCRIPTDIR}"/umnt_shares
XSETUP=$(find /etc/X* -name "Xsetup" 2>/dev/null)
XRESET=$(find /etc/X* -name "Xreset" 2>/dev/null)

[ ! -f "${RESOLUTIONSCRIPT}" -o ! -f "${SHARESCRIPT}" ] && \
	{ logger "openslx vm_runtime: could not find needed scripts on disk. Exiting." ; exit 1 ; }

write_xsetup() {
	logger "openslx vm_runtime: writing ${XSETUP}..."
	cat<<-BISHIER > "${XSETUP}"
		#!/bin/sh
		${SHARESCRIPT} &
		${RESOLUTIONSCRIPT} &
	BISHIER
}

patch_xsetup_shebang() {
	# Patching after first line, to be exact.
	logger "openslx vm_runtime: patching ${XSETUP} after shebang line, if necessary."
	grep -q "${RESOLUTIONSCRIPT}" "${XSETUP}"	|| sed "1 a ${RESOLUTIONSCRIPT} \&" -i "${XSETUP}"
	grep -q "${SHARESCRIPT}" "${XSETUP}"		|| sed "1 a ${SHARESCRIPT} \&" -i "${XSETUP}"
}

write_xreset() {
	logger "openslx vm_runtime: writing ${XRESET}..."
	cat<<-BISHIER > "${XRESET}"
		#!/bin/sh
		${UMOUNTSCRIPT} &
	BISHIER
}

patch_xreset_shebang() {
	# Patching after first line, to be exact.
	logger "openslx vm_runtime: patching ${XRESET} after shebang line, if necessary."
	grep -q "${UMOUNTSCRIPT}" "${XRESET}"	|| sed "1 a ${UMOUNTSCRIPT} \&" -i "${XRESET}"
}

case "${DISTRIBUTION}" in
	opensuse) logger "openslx vm_runtime: openSuse detected."
		if [ ! -e "${XSETUP}" ]; then
			XSETUP=/etc/X11/xdm/Xsetup
			write_xsetup
		else
			logger "openslx vm_runtime: patching ${XSETUP}."
			if ! [ grep -c /etc/sysconfig/displaymanager "$XSETUP" 2>/dev/null 1>&2 ]; then
				logger "openslx vm_runtime: Xsetup: openSuse marker found, patching."
				sed "s#/etc/sysconfig/displaymanager#/etc/sysconfig/displaymanager\n"${SHARESCRIPT}" \&\n${RESOLUTIONSCRIPT} \&#g" \
					-i "${XSETUP}"
			else
				logger "openslx vm_runtime: Xsetup: openSuse marker not found, patching after shebang line."
				xsetup_patch_shebang
			fi
			logger "openslx vm_runtime: patching ${RESET}."
			patch_xreset_shebang
		fi
		;;
	ubuntu)	logger "openslx vm_runtime: Ubuntu detected, version ${VERSION}."
		# Ubuntu has at least in version 14.04 LTS a bug leading to missing Xsetup/Xreset entries:
		grep -q "session-setup-script=/etc/X11/Xsetup" /etc/lightdm/lightdm.conf.d/50-myconfig.conf \
			|| { 	sed "$ a session-setup-script=/etc/X11/Xsetup" -i /etc/lightdm/lightdm.conf.d/50-myconfig.conf
				logger "openslx vm_runtime: session-setup-script patched into /etc/lightdm/lightdm.conf.d/50-myconfig.conf."; }
		grep -q "session-reset-script=/etc/X11/Xreset" /etc/lightdm/lightdm.conf.d/50-myconfig.conf \
			|| {	sed "$ a session-reset-script=/etc/X11/Xreset" -i /etc/lightdm/lightdm.conf.d/50-myconfig.conf
				logger "openslx vm_runtime: session-reset-script patched into /etc/lightdm/lightdm.conf.d/50-myconfig.conf."; }
		if [ ! -e "${XSETUP}" ]; then
			XSETUP=/etc/X11/Xsetup
			write_xsetup
		else
			patch_xsetup_shebang
		fi
		if [ ! -e "${XRESET}" ]; then
			XRESETP=/etc/X11/Xreset
			write_xreset
		else
			patch_xreset_shebang
		fi
		;;
	debian)	logger "openslx vm_runtime: Debian detected."
		;;
	*)	logger "openslx vm_runtime: Unknown distribution, exiting."
		exit 1
		;;
esac

exit 0