#!/bin/sh

# This script is to make unlocking using OpenRC/Consolekit easier when the KDE Screenlocker breaks.
#
# Version: 0.2
# Date written: February 2, 2018
# Last modification: February 17, 2018
#
# Copyright (C) 2018 Daniel Frey
# Copyright (C) 2018 Lars Wendler
#
# This script is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This script is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
#
# Some notes:
#   -The switch processing/argument handling is very basic.
#   -This script assumes session names start with "Session" when listing
#    sessions. This is settable via a variable.
#
# Possible actions:
#   -h : Show help screen
#   -l : List current consolekit sessions
#   -u : Unlock specified session (one parameter required - the session name)
#   -a : Attempt to unlock all sessions

# Return code documentation
#
#  0: Script executed normally
#  1: Root access is not present for script
#  2: No arguments passed
#  3: Multiple actions requested, can only do one at a time
#  4: Argument passed was not recognized
#  5: Multiple arguments passed for unlock single session, only one needed
#  6: The argument required for unlocksession() is missing (internal error)

SCRIPTNAME="$(basename $0)"

# Return code constants
readonly ERR_NORMAL_OPERATION=0
readonly ERR_NO_ROOT=1
readonly ERR_NO_ARGS=2
readonly ERR_TOO_MANY_ACTIONS=3
readonly ERR_INVALID_ARGUMENTS=4
readonly ERR_TOO_MANY_ARGS=5
readonly ERR_INTERNAL_ARG_MISSING=6

# Action parameter constants
readonly ACTION_NONE=0
readonly ACTION_HELP=1
readonly ACTION_LIST=2
readonly ACTION_UNLOCKALL=3
readonly ACTION_UNLOCK=4

# This is what's used to look for a session via consolekit.
# By default, assume it is prefixed with "Session".
SESSION_SEARCH_PREFIX="Session"

# Check to make sure script has root access, if not... abort now!
if [ "$(id -u)" -ne 0 ]; then
	echo "This script must be run as root."
	exit ${ERR_NO_ROOT}
fi

showhelp() {
	cat <<EOF
${SCRIPTNAME}: a script that helps unlock consolekit sessions

Usage: ${SCRIPTNAME} [action] [parameters]

Actions:
	-l : list current sessions available for unlocking 
	-u : unlock session specified as a parameter
	-a : attempt to unlock all current sessions
	-h : this screen

Parameters:
	The -u parameter requires a session name to unlock, use -l to 
	list sessions.

Example:
	To unlock a single session, use:
	${SCRIPTNAME} -u Session1

No arguments will show this screen.
EOF
}

listsessions() {
	# Get a list of all sessions, and remove the full colon from the session name
	ALLSESSIONS=$(ck-list-sessions | grep "^${SESSION_SEARCH_PREFIX}" | awk -F : '{print $1}')

	echo
	echo "Sessions present on this machine, space-delineated:"
	echo
	echo ${ALLSESSIONS}
	echo
	echo
	echo "Session detail (to help locate a specific session:"
	ck-list-sessions | grep -A 2 "^${SESSION_SEARCH_PREFIX}"
}

unlocksession() {
	# This function expects one parameter set (the session to unlock).
	# Make sure the parameter exists before continuing.
	if [ -z "${1}" ]; then 
		showhelp
		exit ${ERR_INTERNAL_ARG_MISSING}
	fi

	echo "Attempting to unlock session $1; messages from dbus are not suppressed."

	# Finally, request the unlock.
	dbus-send --system --print-reply --dest="org.freedesktop.ConsoleKit" /org/freedesktop/ConsoleKit/$1 org.freedesktop.ConsoleKit.Session.Unlock
}

unlockallsessions() {
	# Get a list of all sessions, and remove the full colon from the session name
	ALLSESSIONS=$(ck-list-sessions | grep "^${SESSION_SEARCH_PREFIX}" | awk -F : '{print $1}')

	echo "Attempting to unlock all sessions. Messages from dbus are not suppressed."
	echo
	# Loop through results, attempt to unlock all sessions.
	# Count them and report at the end.
	COUNT=0
	for i in ${ALLSESSIONS}; do
		dbus-send --system --print-reply --dest="org.freedesktop.ConsoleKit" /org/freedesktop/ConsoleKit/$i org.freedesktop.ConsoleKit.Session.Unlock
		let "COUNT+=1"
	done

	echo
	echo "Attempted to unlock ${COUNT} session(s)."
}

check_actions() {
	# Make sure multiple actions are not chosen.
	if [ ${ACTION} -ne ${ACTION_NONE} ]; then
		echo "You can only declare one action at a time!"
		echo ""
		showhelp
		exit ${ERR_TOO_MANY_ACTIONS}
	fi
}

# Start of "main" routine

# Initialize variables:
#     ACTION=default 0; used to make sure more than one action are not
#          specified at the same time. If an invalid argument was passed
#          (e.g. one without the hyphen prefix) it will be caught as well.
ACTION="${ACTION_NONE}"

# Show help if no arguments provided at all
if  [ $# -eq 0 ]; then
	showhelp
	exit ${ERR_NO_ARGS}
fi

# Process arguments passed, setting environment appropriately.
# During this check, ensure only one action was requested. This
# script will not do multiple things at a time.
while getopts “hlau:” OPTION; do
	case ${OPTION} in
		h)	# Help action
			check_actions
			ACTION=${ACTION_HELP}
		;;
                l)	# List action
			check_actions
			ACTION="${ACTION_LIST}"
		;;
		a)	# Enable all USB hubs/devices action
			check_actions
			ACTION="${ACTION_UNLOCKALL}"
		;;
		u)	# Enable specific hub/device via find command action
			check_actions
			ACTION="${ACTION_UNLOCK}"

			# Save session name passed for later
			UNLOCKSESSION="${OPTARG}"
		;;
		?)	# Unknown parameter
			showhelp
			exit ${ERR_INVALID_ARGUMENTS}
		;;
	esac
done

# If script reaches this point, only one action was specified, so it is safe
# to continue processing.
case ${ACTION} in
	${ACTION_HELP})		# help action
		showhelp
	;;
	${ACTION_LIST})		# list action
		listsessions
	;;
	${ACTION_UNLOCKALL}) 	# unlock all sessions
		unlockallsessions
	;;
	${ACTION_UNLOCK})	# unlock single session
		unlocksession ${UNLOCKSESSION}
	;;
	*)
		echo "Unrecognized action."
		echo
		showhelp
		exit ${ERR_INVALID_ARGUMENTS}
	;;
esac

exit ${ERR_NORMAL_OPERATION}