#!/bin/bash

DISK_UUID="12E6B87AE6B86021"
IQN="iqn.2000-01.com.synology:SR3.VMs"
PORTAL_IP="192.168.0.3"
MOUNT_DIR="/home/dunestorm/VMs"
MONITOR_PROC="vmware"
MONITOR_PROC_CNT=7

# Do not modify
_MONITOR_PROC_CNT=$(pgrep -f $MONITOR_PROC | wc -l)
_ISCSI_CON=""
_FLAG_FORCE=0

# The use of iscsiadm requires admin privilages
read_iscsi_con (){
	_ISCSI_CON=$(iscsiadm -m session)
}

show_usage (){
	echo "[Usage]"
	echo "Please use either '-m (--mount)' to mount or '-u (--umount)' to unmount this volume."
	echo ""
	echo "Additional Options:"
	echo "'-s (--status)'"
	echo "'-r (--release)'"
	exit 1;
}

report_status (){
	echo "INFO: Process '${MONITOR_PROC}' has ${_MONITOR_PROC_CNT} instances running."

	if [ $(ls $MOUNT_DIR/. | wc -l) -ge 1 ]
	then
		echo ""
		echo "Directory is mounted at:" $MOUNT_DIR
	else
		echo ""
		echo "Directory is un-mounted from:" $MOUNT_DIR
	fi

	read_iscsi_con
	echo ""
	echo "There is/are currently '$(${_ISCSI_CON} 2>&1 | wc -l)' iSCSI connection(s) open:"
	echo "${_ISCSI_CON}"
}

check_proc_status (){
	if [ ${_MONITOR_PROC_CNT} -gt $MONITOR_PROC_CNT ]
	then
		echo "WARNING: process '${MONITOR_PROC}' is still running, unable to unmount volume safely."
		exit 2;
	else
		echo "INFO: Process ${MONITOR_PROC} is not running."
	fi
}

mount_func (){
	echo "[Attempting to mount iSCSI volume]"

	if [[ ${_ISCSI_CON} == *${IQN}* ]] && [[ $_FLAG_FORCE -eq 0 ]]
	then
		echo "WARNING: You're already connected to the '${IQN}' iSCSI target."
		echo "Use the -f (--force) flag to bypass this warning."
		exit 2;
	fi

	iscsiadm --mode node --targetname $IQN --portal $PORTAL_IP --login
	sleep 3
	mount /dev/disk/by-uuid/$DISK_UUID $MOUNT_DIR -o noauto,noperm
	report_status
}

umount_func (){
	echo "[Attempting to un-mount iSCSI volume]"

	if [[ $_FLAG_FORCE -eq 0 ]]; then 
		check_proc_status
	fi

	if [[ ${_ISCSI_CON} != *${IQN}* ]] && [[ $_FLAG_FORCE -eq 0 ]]
	then
		echo "WARNING: You're not currently connected to the '${IQN}' iSCSI target."
		echo "Use the -f (--force) flag to bypass this warning."
		exit 2;
	fi

	umount -l $MOUNT_DIR
	sleep 3
	iscsiadm --mode node --targetname $IQN --portal $PORTAL_IP --logout
	report_status
}

check_admin (){
	if [[ $EUID -ne 0 ]]
	then
		echo "This command requires root, please re-run with appropriate permissions."
		exit 1;
	fi
}

# Process input parameters
while (( "$#" )); do
	case "$2" in
		-f|--force)
		_FLAG_FORCE=1
		;;
	esac
	case "$1" in
		-m|--mount)
			check_admin
			read_iscsi_con
			mount_func
			;;
		-u|--umount)
			check_admin
			read_iscsi_con
			umount_func
			;;
		-s|--status)
			echo "[Showing status of mount-point]"
			check_admin
			read_iscsi_con
			report_status
			;;
		-r|--release)
			echo "Smart iSCSI Mounter v0.97"
			;;
		-*)
			show_usage
			;; 
	esac
	exit 0;
	done

# Show usage if no parameters have been passed
if [[ $# -eq 0 ]]
then
	show_usage
fi