#!/usr/bin/env bash
# Ensure bash path is found

# shellcheck source=/etc/os-release
# use shellcheck to declare which file to source

# Using set to make the script safer
set -e          # Exit on error
set -u          # Exit on undefined variable
set -x          # Print commands for debugging
set -a          # Export all variables
set -C          # Disable overwriting of files
set -o pipefail # Exit on pipe error
# set -euxaCo pipefail # All options

# Use the built-in trap command to catch error lines and signal numbers
trap 'printf "Error on line %d with signal %s" "$LINENO" "$?"' ERR # Exit on error
# Also use trap to catch interrupt signals and exit cleanly with a message to the user and a return code
trap 'printf "Interrupted on line %d with signal %s" "$LINENO" "$?"' INT SIGHUP SIGINT SIGTERM

# Get script name using parameter expansion to not spawn a new subprocess
SCRIPT_NAME="${0##*/}"

# We will be using printf instead of echo because it is more standardised.
# Also we will be using the test command's functionality as
# [[ because like this it constitutes a keyword and not a command.
# Functions will be defined as function "name" {body}" to make them
# more clear and () will not be used since using the keyword function renders them redundant

# We are taking for granted that the os-release file is in /etc as
# it has become a standard in most GNU/Linux distributions using systemd.
# We'll be using the -e flag just in case it is actually a symlink to another location.
# The get_distro function will use short if statements to check for the os-release file existence and readability.
# Then it will source it and output the distribution's name or exit in case of failure of either case.
function get_distro {
	if [[ -e /etc/os-release ]] && [[ -r /etc/os-release ]]; then # Check if file exists and is readable
		. /etc/os-release                                            # Source the file
		printf "%s" "$NAME"                                          # Output the distribution's name
	else                                                          # If the file does not exist or is not readable
		printf "%s" "File os-release not found or not readable"      # Output error message
		exit 1                                                       # Exit with error code 1
	fi
}

# The get_package_manager function will take the output of the get_distro function and determine
# which is the package manager used for the most popular server distros and exit if it is not found.
function get_package_manager {
	local distro                    # Declare distro as a local variable
	distro="$(get_distro)"          # Get the distribution name
	case "$distro" in               # Use case to check for the distribution name
		"Ubuntu" | "Debian GNU/Linux") # If the distribution is Ubuntu or Debian
			printf "%s" "apt"             # Output apt
			;;
		"CentOS Linux" | "Fedora" | "Red Hat Enterprise Linux Server") # If the distribution is CentOS, Fedora or RHEL
			printf "%s" "dnf"                                             # Output dnf
			;;

		"openSUSE Leap")      # If the distribution is OpenSUSE
			printf "%s" "zypper" # Output zypper
			;;
		*)
			# If the distribution is none of the above, output unsupported distribution
			# and exit with error code 1
			printf "%s" "Unsupported distribution"
			exit 1 # Exit with error code 1
			;;
	esac
}

# The install_packages function will take the output of the get_package_manager function and install any
# package passed as an argument to it. It will also check if the package manager is known and exit if it is not.
function install_packages {
	local package_manager                    # Declare package_manager as a local variable
	package_manager="$(get_package_manager)" # Get the package manager
	case "$package_manager" in               # Use case to check for the package manager
		"apt")                                  # If the package manager is apt
            printf "%s" 'debconf debconf/frontend select Noninteractive' | sudo debconf-set-selections
			export DEBIAN_FRONTEND=noninteractive
            export NEEDRESTART_MODE=a
            export DEBIAN_PRIORITY=critical
            # Running sudo with -E will preserve the environment variables set in the script
            sudo -E apt update -y && sudo apt upgrade -y # Update the package list and upgrade the packages
			sudo -E apt install -y "$@"               # Install the packages passed as arguments
			;;
		"dnf")                    # If the package manager is dnf
            sudo dnf upgrade -y      # Update the package list
			sudo dnf install -y "$@" # Install the packages passed as arguments
			;;
		"zypper")                    # If the package manager is zypper
            sudo zypper update -y       # Update the package list
			sudo zypper install -y "$@" # Install the packages passed as arguments
			;;
		*)
			# If the package manager is not one of the above, output unsupported package manager
			# and exit with error code 1
			printf "%s" "Unsupported package manager"
			exit 1 # Exit with error code 1
			;;
	esac
}

# The check_dependencies function will check if the dependencies defined in a local array are not installed
# and store the ones that are indeed absent in another local array.
# Then it will install the packages that are missing by invoking the install_packages function.
function check_dependencies { # systemd-container is for machinectl
	local dependencies=(fuse-overlayfs dbus-user-session uidmap slirp4netns systemd-container at htop curl git sudo vim ssh wget fail2ban) # Declare dependencies as a local array
	#> see what to do with name differences between distros if any <#
	local missing_dependencies=()              # Declare missing_dependencies as a local array
	for dependency in "${dependencies[@]}"; do # Loop through the dependencies array
		# If the dependency is not installed, add it to the missing_dependencies array
		! command -v "$dependency" &> /dev/null && missing_dependencies+=("$dependency")
	done
	# If the missing_dependencies array is not empty, install the packages
	[[ ${#missing_dependencies[@]} -ne 0 ]] && install_packages "${missing_dependencies[@]}"
}

# Global array of the service names to be restarted
services=()

# The hardenSSH function will use sed to modify the sshd_config file to have the following settings:
# - Allow ssh access to users in the sudo group only
# - Change the port to 22100 if it is available
# - Configure idle timeout to 5 minutes
# - Limit the number of authentication attempts to 3
# - Disable root login
# - Disable empty passwords
# - Disable ssh protocol 1
# - Disable password authentication and only allow public key authentication
# - Disable X11 forwarding for security reasons (X11 forwarding is not needed for ssh)
# - Disable agent forwarding to prevent ssh-agent hijacking
# Then it will store the sshd service name in the services array.
function hardenSSH {
	# Check if the sshd_config file exists and is readable
	# If it is, then modify it using sed and restart the sshd service
	# If it is not, then output an error message and exit with error code 1
	# The -i flag is used to modify the file in place
	# We split the sed command into multiple lines for readability purposes
	# and to avoid calling it multiple times
	if [[ -e /etc/ssh/sshd_config ]] && [[ -r /etc/ssh/sshd_config ]]; then
		sudo sed -i \
			-e 's/^#AllowGroups.*/AllowGroups sudo/' \
			-e 's/^#Port.*/Port 22100/' \
			-e 's/^#ClientAliveInterval.*/ClientAliveInterval 300/' \
			-e 's/^#ClientAliveCountMax.*/ClientAliveCountMax 3/' \
			-e 's/^#PermitRootLogin.*/PermitRootLogin no/' \
			-e 's/^#PermitEmptyPasswords.*/PermitEmptyPasswords no/' \
			-e 's/^#Protocol.*/Protocol 2/' \
			-e 's/^#PasswordAuthentication.*/PasswordAuthentication no/' \
			-e 's/^#X11Forwarding.*/X11Forwarding no/' \
			-e 's/^X11Forwarding.*/X11Forwarding no/' \
			-e 's/^#AllowAgentForwarding.*/AllowAgentForwarding no/' \
			/etc/ssh/sshd_config
		services+=("sshd") # Add sshd to the services array
	else
		printf "%s" "File sshd_config not found or not readable"
		exit 1
	fi
}

function getCorrectFirewall {
	local distro                    # Declare distro as a local variable
	distro="$(get_distro)"          # Get the distribution name
	case "$distro" in               # Use case to check for the distribution name
		"Ubuntu" | "Debian GNU/Linux") # If the distribution is Ubuntu or Debian
            printf "%s" 'debconf debconf/frontend select Noninteractive' | sudo debconf-set-selections
			export DEBIAN_FRONTEND=noninteractive
            export NEEDRESTART_MODE=a
            export DEBIAN_PRIORITY=critical
            sudo -E apt install ufw -y # Install ufw
            printf "%s" "ufw" # Output ufw
			;;
		"CentOS Linux" | "Fedora" | "Red Hat Enterprise Linux Server") # If the distribution is CentOS, Fedora or RHEL
			sudo dnf install firewalld -y # Install firewalld
            printf "%s" "firewalld" # Output firewalld
			;;

		"openSUSE Leap")      # If the distribution is OpenSUSE
			sudo zypper install firewalld -y # Install firewalld
            printf "%s" "firewalld" # Output firewalld
			;;
		*)
			# If the distribution is none of the above, output unsupported distribution
			# and exit with error code 1
			printf "%s" "Unsupported distribution"
			exit 1 # Exit with error code 1
			;;
	esac

}

function getCorrectKernelSecurityModule {
	local distro                    # Declare distro as a local variable
	distro="$(get_distro)"          # Get the distribution name
	case "$distro" in               # Use case to check for the distribution name
		"Ubuntu") # If the distribution is Ubuntu
			sudo apt install apparmor-profiles apparmor-utils apparmor-profiles-extra -y # Install apparmor
            printf "%s" "apparmor" # Output apparmor
			;;
        "Debian GNU/Linux") # If the distribution is Debian
            printf "%s" 'debconf debconf/frontend select Noninteractive' | sudo debconf-set-selections
			export DEBIAN_FRONTEND=noninteractive
            export NEEDRESTART_MODE=a
            export DEBIAN_PRIORITY=critical
            sudo -E apt install apparmor apparmor-profiles apparmor-profiles-extra apparmor-utils auditd python3-apparmor -y # Install apparmor
            printf "%s" "apparmor" # Output apparmor
            ;;
		"CentOS Linux" | "Fedora" | "Red Hat Enterprise Linux Server") # If the distribution is CentOS, Fedora or RHEL
			sudo dnf install selinux container-selinux -y # Install selinux
            printf "%s" "selinux" # Output selinux
			;;

		"openSUSE Leap")      # If the distribution is OpenSUSE
			sudo zypper install -t pattern apparmor -y # Install apparmor
            printf "%s" "apparmor" # Output apparmor
			;;
		*)
			# If the distribution is none of the above, output unsupported distribution
			# and exit with error code 1
			printf "%s" "Unsupported distribution"
			exit 1 # Exit with error code 1
			;;
    esac
}

function firewallInit {
    getCorrectFirewall # Get the correct firewall installed
    # Determine if ufw or firewalld is installed
    whereis ufw | grep -q /ufw && currentFirewall="ufw" || currentFirewall="firewalld"
    case "$currentFirewall" in
        ufw)
            sudo ufw default allow outgoing # Allow outgoing connections
            sudo ufw default deny incoming  # Deny incoming connections
            sudo ufw allow 22100/tcp        # Allow ssh connections on port 22100
            sudo ufw allow 8000/tcp         # Allow portainer connections on port 8000
            sudo ufw allow 9443/tcp         # Allow portainer connections on port 9443
        ;;
        firewalld)
            sudo systemctl enable firewalld # Enable the firewall on boot
            sudo firewall-cmd --permanent --add-port=22100/tcp # Allow ssh connections on port 22100
            sudo firewall-cmd --permanent --add-port=8000/tcp # Allow portainer connections on port 8000
            sudo firewall-cmd --permanent --add-port=9443/tcp # Allow portainer connections on port 9443
        ;;
        *)
            printf "%s" "Unsupported firewall"
            exit 1
        ;;
    esac
}

function kernelSecurityModuleInit {
    getCorrectKernelSecurityModule # Get the correct kernel security module installed
    # Determine if apparmor or selinux is installed
    whereis apparmor | grep -q /apparmor && kernelSecurityModule="apparmor" || kernelSecurityModule="selinux"
    case "$kernelSecurityModule" in
        apparmor)
            sudo systemctl enable --now apparmor # Enable the kernel security module on boot and start it
            sudo aa-enforce /etc/apparmor.d/* # Enforce all apparmor profiles
        ;;
        selinux)
            sudo systemctl enable --now selinux # Enable the kernel security module on boot and start it
##            printf "%s" "{\"selinux-enabled\":true}" | sudo tee /etc/docker/daemon.json # Enable selinux in docker
            sudo setenforce 1 # Enforce selinux
            sudo sed -i 's/^SELINUX=.*/SELINUX=enforcing/' /etc/selinux/config # Set selinux to enforcing
 ##           sudo systemctl restart docker # Restart docker
 ##           sudo restorecon -Rv /var/lib/docker # Restore the selinux context of the docker directory
 ##           sudo restorecon -Rv /usr/bin # Restore the selinux context of the docker directory
        ;;
        *)
            printf "%s" "Unsupported kernel security module"
            exit 1
        ;;
    esac
}

function dockerInit {
    # Set up rootless docker
    # Enable linger for the secdep user
    sudo loginctl enable-linger secdep
    # Enable dbus for the secdep user
    sudo machinectl shell secdep@ /bin/bash -c "systemctl --user enable --now dbus"
    # Install rootless docker
    sudo machinectl shell secdep@ /bin/bash -c "curl -fsSL https://get.docker.com/rootless | sh"
    # Add important environment variables to the secdep user's .bashrc
    sudo su secdep << 'EOF'
printf "%s\n" "export PATH=/home/$USER/bin:$PATH" >> "$HOME/.bashrc"
printf "%s\n" "export DOCKER_HOST=unix:///run/user/$UID/docker.sock" >> "$HOME/.bashrc"
EOF
    # Enable the user to bind to ports below 1024
    sudo setcap cap_net_bind_service=ep /home/secdep/bin/rootlesskit
    # Restart docker
    sudo machinectl shell secdep@ /bin/bash -c "systemctl --user restart docker"

#     # Create a new docker network to dissalow communication between containers
#     ##sudo docker network create --driver bridge -o "com.docker.network.bridge.enable_icc"="false" dockerNetworkNoICC
    # Get all arguments passed to the function and store them in the dockerImages array
    local dockerImages=("$@")
    # Using -f instead of -e to check if the file exists AND that it is a regular file
    [[ -f /root/docker-compose.yml ]] && sudo mv /root/docker-compose.yml /home/secdep/docker-compose.yml
    [[ -f /home/admin/docker-compose.yml ]] && sudo mv /home/admin/docker-compose.yml /home/secdep/docker-compose.yml
    [[ -f /home/ec2-user/docker-compose.yml ]] && sudo mv /home/ec2-user/docker-compose.yml /home/secdep/docker-compose.yml
    [[ -f /home/centos/docker-compose.yml ]] && sudo mv /home/centos/docker-compose.yml /home/secdep/docker-compose.yml
    [[ -f /home/fedora/docker-compose.yml ]] && sudo mv /home/fedora/docker-compose.yml /home/secdep/docker-compose.yml
    [[ -f /home/ubuntu/docker-compose.yml ]] && sudo mv /home/ubuntu/docker-compose.yml /home/secdep/docker-compose.yml
    # Since FileDeployment does not work and we used ScriptFileDeployment which might make the file owned by another user
    # we need to make sure the file is owned by the secdep user.
    # When using [[ -f /home/secdep/docker-compose.yml ]] && sudo chown secdep:secdep /home/secdep/docker-compose.yml
    # it doesn't get executed somehow so we'll send the "no such file or directory" error to /dev/null
    sudo chown secdep:secdep /home/secdep/docker-compose.yml > /dev/null 2>&1
    # Since FileDeployment does not work and we used ScriptFileDeployment which automatically makes the file executable
    # we need to make sure the file is not executable.
    # when using [[ -f /home/secdep/docker-compose.yml ]] && sudo chmod -x /home/secdep/docker-compose.yml
    # it doesn't get executed somehow so we'll send the "no such file or directory" error to /dev/null
    sudo chmod -x /home/secdep/docker-compose.yml > /dev/null 2>&1
    sudo machinectl shell secdep@ /bin/bash -c 'curl -SL https://github.com/docker/compose/releases/download/v2.20.3/docker-compose-linux-x86_64 -o /home/secdep/bin/docker-compose'
    sudo machinectl shell secdep@ /bin/bash -c 'chmod +x /home/secdep/bin/docker-compose'
    sudo machinectl shell secdep@ "$(which bash)" -c '[[ -f "$HOME/docker-compose.yml" ]] && DOCKER_HOST=unix:///run/user/$UID/docker.sock /home/secdep/bin/docker-compose -f /home/secdep/docker-compose.yml up -d'
    # Read the docker-compose.yml file for port mappings to add to the firewall
    CMD_PORTS="cat /home/secdep/docker-compose.yml | sed '/^[[:space:]]*$/d' | grep -A1 ports | grep '[0-9]:[0-9]' | rev | cut -d':' -f1 | rev | grep -Eow '[[:digit:]]+' | tr '\n' ' '"
    sudo -E runuser - secdep -c "$CMD_PORTS" > /dev/null 2>&1 && PORTS="$(sudo -E runuser - secdep -c "$CMD_PORTS")" || PORTS=""
    # Loop through the ports in the PORTS variable
    if [[ -n "$PORTS" ]]; then
        for port in $PORTS; do
            # Allow the port in the firewall
            case "$currentFirewall" in
                ufw)
                    sudo ufw allow "$port"/tcp
                ;;
                firewalld)
                    sudo firewall-cmd --permanent --add-port="$port"/tcp
                ;;
                *)
                    printf "%s" "Unsupported firewall"
                    exit 1
                ;;
            esac
        done
    fi
    # Portainer is a docker image that provides a web interface for docker
    # which will be installed and run on port 9443 by default to make it easier to manage docker
    # url to follow after the installation is complete: https://vps_ip:9443
    # the https:// part is important as portainer will not work without it
    sudo -E runuser - secdep -c 'docker run -d -p 8000:8000 -p 9443:9443 --name=portainer --restart=always -v /run/user/$UID/docker.sock:/var/run/docker.sock -v portainer_data:/data portainer/portainer-ce'
    # Check if the dockerImages array is empty and return 0 if it is
    [[ "${#dockerImages[@]}" -eq 0 ]] && return 0
    # Loop through the dockerImages array
    # The dockerImages array contains all the docker images to install and run
    for dockerImage in "${dockerImages[@]}"; do
        # If dockerImage contains a ":" character (if it is a docker image with a tag)
        # then store the docker image name in the dockerImageName variable
        [[ "$dockerImage" == *":"* ]] && dockerImageName="${dockerImage%:*}" || dockerImageName="$dockerImage"
        # Same goes for "/"
        [[ "$dockerImageName" == *"/"* ]] && dockerImageName="${dockerImageName%/*}"
        # No need to pull the docker image as the run command will do it automatically
        # Run the docker image in the background,
        # with the restart always option and the name of the docker image
        # The --security-opt=no-new-privileges option will prevent the docker image from gaining new privileges
        # The --cap-drop all option will drop all capabilities from the docker image
        # The --cap-add NET_BIND_SERVICE option will add the NET_BIND_SERVICE capability to the docker image
        # The --read-only option will mount the docker image as read-only
        # The --tmpfs /opt option will mount the /opt directory as a tmpfs
        # The --network dockerNetworkNoICC option will connect the docker image to the dockerNetworkNoICC network
        # The -v /:/host option will enable the docker rootless mode
        # # The --user secdep option will run the docker image as the secdep user to prevent privilege escalation
        # sudo -u secdep bash -c 'mkdir -p /home/secdep/opt'
        CMD="docker pull $dockerImage"
        # CMD="docker run -d --restart always --name $dockerImageName --security-opt=no-new-privileges --cap-drop all --cap-add NET_BIND_SERVICE --tmpfs /home/secdep/opt -v /:/host $dockerImage"
        # CMD="docker run -d --restart always --name $dockerImageName --security-opt=no-new-privileges --cap-drop all --cap-add NET_BIND_SERVICE --read-only --tmpfs /home/secdep/opt -v /:/host $dockerImage"
        sudo -E runuser - secdep -c "$CMD"
    done
}

# The selinuxConfig function will set up and configure selinux with sane defaults.
# function selinuxConfig {
#     # Set the selinux boolean to allow docker to use the network
#     sudo setsebool -P docker_connect_any 1
# }

# Fix banaction ufw with iptables
# Does not always persist after reboot.
function configureFail2ban {
FAIL2BAN_LOCAL=$(cat <<'EOF'
[Definition]
logtarget = /var/log/fail2ban/fail2ban.log
allowipv6 = auto
EOF
)
printf "%s" "$FAIL2BAN_LOCAL" | sudo tee /etc/fail2ban/fail2ban.local
FAIL2BAN_SSH_JAIL_LOCAL=$(cat <<'EOF'
[sshd]
backend = systemd
enabled = true
filter = sshd
banaction = ufw
maxretry = 3
# 3 failed attempts in 600 seconds = 10 minutes
findtime = 1d
bantime = 1d
ignoreip = 127.0.0.1/8
EOF
)
FAIL2BAN_JAIL_LOCAL=$(cat <<'EOF'
[DEFAULT]
backend = systemd
bantime = 1d
EOF
)
printf "%s" "$FAIL2BAN_JAIL_LOCAL" | sudo tee /etc/fail2ban/jail.local
printf "%s" "$FAIL2BAN_SSH_JAIL_LOCAL" | sudo tee /etc/fail2ban/jail.d/sshd.local
FAIL2BAN_FILTER=$(cat <<'EOF'
[Definition]
failregex = ^.*DROP_.*SRC=<ADDR> DST=.*$
journalmatch = _TRANSPORT=kernel
EOF
)
printf "%s" "$FAIL2BAN_FILTER" | sudo tee /etc/fail2ban/filter.d/fwdrop.local
HARDEN_FAIL2BAN_SERVICE=$(cat <<'EOF'
[Service]
PrivateDevices=yes
PrivateTmp=yes
ProtectHome=read-only
ProtectSystem=strict
ReadWritePaths=-/var/run/fail2ban
ReadWritePaths=-/var/lib/fail2ban
ReadWritePaths=-/var/log/fail2ban
ReadWritePaths=-/var/spool/postfix/maildrop
ReadWritePaths=/run/xtables.lock
CapabilityBoundingSet=CAP_AUDIT_READ CAP_DAC_READ_SEARCH CAP_NET_ADMIN CAP_NET_RAW
EOF
)
sudo mkdir -p /etc/systemd/system/fail2ban.service.d
printf "%s" "$HARDEN_FAIL2BAN_SERVICE" | sudo tee /etc/systemd/system/fail2ban.service.d/override.conf
sudo systemctl daemon-reload
sudo systemctl enable --now fail2ban
printf "%s" "LogLevel VERBOSE" | sudo tee -a /etc/ssh/sshd_config
}

function enableServices {
    for service in "${services[@]}"; do
        sudo systemctl restart "$service"
    done
    whereis ufw | grep -q /ufw && currentFirewall="ufw" || currentFirewall="firewalld"

    # With the if block it doesn't error out at firewalld check so we do it this way
    # For ufw
    if [[ "$currentFirewall" == "ufw" ]]; then
        # Enable the firewall
        sudo ufw --force enable
        # Enable and start the firewall on boot
        sudo systemctl enable --now ufw
    # For firewalld
    elif [[ "$currentFirewall" == "firewalld" ]]; then
        # Reload the firewall
        sudo firewall-cmd --reload
    else
        printf "%s" "Somehow there is no firewall installed"
        exit 1
    fi
}

# Sometimes the user is not deleted after the script is run
function deleteRemainingUsers {
    # Delete possible remaining users
    cat << EOF | sudo tee /root/delete_users.sh
[[ -d /home/admin ]] && sudo userdel -r admin && sudo groupdel admin
[[ -d /home/ec2-user ]] && sudo userdel -r ec2-user && sudo groupdel ec2-user
[[ -d /home/centos ]] && sudo userdel -r centos && sudo groupdel centos
[[ -d /home/fedora ]] && sudo userdel -r fedora && sudo groupdel fedora
[[ -d /home/ubuntu ]] && sudo userdel -r ubuntu && sudo groupdel ubuntu
sudo rm -f /root/delete_users.sh
EOF
    sudo systemctl enable --now atd
    # Use at as root because if it is run as one of the users above it will fail
    sudo at now + 1 minute <<< "bash /root/delete_users.sh"
}

# The main function will call the declared functions in order and exit if any of them fails.
# It will also pass any arguments passed to the script to the dockerInit function.
# Then it will output a message to the user and reboot the system in 2 minutes.
function main {
    printf "%s" "$SCRIPT_NAME script started"
	check_dependencies || exit 1                    # Check dependencies and exit if it fails
    printf "%s" "Dependencies installed"
    hardenSSH || exit 1                             # Harden ssh and exit if it fails
    printf "%s" "SSH hardened"
    firewallInit || exit 1                          # Initialize the firewall and exit if it fails
    printf "%s" "Firewall initialized"
    kernelSecurityModuleInit || exit 1              # Initialize the kernel security module and exit if it fails
    printf "%s" "Kernel security module initialized"
    configureFail2ban || exit 1                     # Initialize fail2ban and exit if it fails
    printf "%s" "Fail2ban configured"
#    selinuxConfig       # Configure selinux
    # Call the dockerInit function with the arguments passed to the script
    dockerInit "$@" || exit 1                       # Initialize docker and exit if it fails
    enableServices || exit 1
    deleteRemainingUsers || exit 1
	printf "%s" "$SCRIPT_NAME script finished"      # Output message to the user
	printf "%s" "System will reboot momentarily"    # Output message to the user
    # Reboot the system in 2 minutes
    sudo shutdown -r +2
}

# Call the main function
main "$@"

exit 0 # The right and proper way to exit a script
