Update jlmkr.sh

jlmkr.sh

@@ -7,18 +7,19 @@ ABSOLUTE_SCRIPT_PATH="$(realpath "${BASH_SOURCE[0]}")"
 SCRIPT_NAME=$(basename "${ABSOLUTE_SCRIPT_PATH}")
 SCRIPT_DIR_PATH="$(dirname "${ABSOLUTE_SCRIPT_PATH}")"
 
-CREATE_DONE=
-JAILS_DIR_PATH='jails'
-JAIL_ROOTFS_NAME='rootfs'
-JAIL_PATH=
-
 USAGE="WARNING: EXPERIMENTAL AND WORK IN PROGRESS, USE ONLY FOR TESTING!
-
+TODO: add version string
 Usage: ./${SCRIPT_NAME} COMMAND [ARG...]
 
 TODO: complete writing usage
 "
 
+JAILS_DIR_PATH='jails'
+JAIL_ROOTFS_NAME='rootfs'
+JAIL_PATH=
+JAIL_CONFIG_NAME='config'
+JAIL_START_SCRIPT_NAME='start.sh'
+
 fail() {
 	echo -e "$1" >&2 && exit 1
 }
@@ -38,23 +39,31 @@ trap 'err $LINENO' ERR
 # START RUN FUNCTIONALITY
 #########################
 
-run_jail() (
+start_jail() {
-    # Create a sub-shell to source the conf file
+	local jail_config_path jail_start_script_path docker_compatible gpu_passthrough key value
+
+	jail_config_path="${1}/${JAIL_CONFIG_NAME}"
+	jail_start_script_path="${1}/${JAIL_START_SCRIPT_NAME}"
+
+	! [[ -f "${jail_start_script_path}" ]] && fail "ERROR: Couldn't find: ${jail_start_script_path}"
+	! [[ -f "${jail_config_path}" ]] && fail "ERROR: Couldn't find: ${jail_config_path}"
+
+	echo 'Load the config'
+
+	# TODO: also load the additional (user) args for nspawn from this file!
+	while IFS="=" read -r key value || [ -n "$key" ]; do
+		case "${key}" in
+		"DOCKER_COMPATIBLE") docker_compatible="$value" ;;
+		"GPU_PASSTHROUGH") gpu_passthrough="$value" ;;
+		esac
+	done <"${jail_config_path}"
+
+	echo 'Config loaded'
 
-    # Define as global vars: they are also global vars in the sourced start script
-    DOCKER_COMPATIBLE=
-    GPU_PASSTHROUGH=
 	SYSTEMD_RUN_ADDITIONAL_ARGS=()
 	SYSTEMD_NSPAWN_ADDITIONAL_ARGS=()
 
-    echo 'Load the config'
+	if [[ "${docker_compatible}" -eq 1 ]]; then
-    # shellcheck disable=SC1090
-    . "${1}"
-    echo 'Config loaded'
-
-    set -eEuo pipefail
-    if [[ "$(type -t start)" == 'function' ]]; then
-        if [[ "${DOCKER_COMPATIBLE}" -eq 1 ]]; then
 		# Enable ip forwarding on the host (docker needs it)
 		echo 1 >/proc/sys/net/ipv4/ip_forward
 		# To properly run docker inside the jail, we need to lift restrictions
@@ -65,7 +74,7 @@ run_jail() (
 		SYSTEMD_NSPAWN_ADDITIONAL_ARGS+=(--capability=all --system-call-filter='add_key keyctl bpf')
 	fi
 
-        if [[ "${GPU_PASSTHROUGH}" -eq 1 ]]; then
+	if [[ "${gpu_passthrough}" -eq 1 ]]; then
 		SYSTEMD_NSPAWN_ADDITIONAL_ARGS+=(--property=DeviceAllow='char-drm rw')
 
 		# Detect intel GPU device and if present add bind flag
@@ -74,25 +83,22 @@ run_jail() (
 		# TODO: add bind mount flags in case of nvidia GPU passthrough
 	fi
 
+	# Pass the two arrays to the start script
+	# https://stackoverflow.com/a/43687593
 	echo "Starting jail..."
-        start
+
-    else
+	"./${jail_start_script_path}" \
-        echo "Can't call the start function since start.sh didn't contain one..."
+		"${#SYSTEMD_RUN_ADDITIONAL_ARGS[@]}" "${SYSTEMD_RUN_ADDITIONAL_ARGS[@]}" \
-    fi
+		"${#SYSTEMD_NSPAWN_ADDITIONAL_ARGS[@]}" "${SYSTEMD_NSPAWN_ADDITIONAL_ARGS[@]}"
-)
+}
 
 ############################
 # START CREATE FUNCTIONALITY
 ############################
 
 cleanup() {
-    # If the script didn't complete (not CREATE_DONE) then
+	# Remove the JAIL_PATH (if set, a directory and not the root directory)
-    # remove the JAIL_PATH (if set and a directory)
+	[[ -d "${JAIL_PATH}" ]] && echo -e "\n\nCleaning up: ${JAIL_PATH}\n" && rm -rf "${JAIL_PATH}"
-    if [[ "${CREATE_DONE}" -ne 1 && -n "${JAIL_PATH}" && -d "${JAIL_PATH}" &&
-        "${JAIL_PATH}" != "${JAILS_DIR_PATH}" && "${JAIL_PATH}" != "/" ]]; then
-        echo -e "\n\nCleaning up: ${JAIL_PATH}\n"
-        rm -rf "${JAIL_PATH}"
-    fi
 }
 
 stat_chmod() {
@@ -112,28 +118,19 @@ template_start_script() {
 	echo "$((LINENO + 1))" && return
 	# TEMPLATE START
 	#!/bin/bash
-
-    # YOU CAN MANUALLY EDIT THE SETTINGS BELOW
-
-    DOCKER_COMPATIBLE=PLACEHOLDER_DOCKER_COMPATIBLE
-    GPU_PASSTHROUGH=PLACEHOLDER_GPU_PASSTHROUGH
-
-    # DO NOT EDIT THE SCRIPT FROM HERE ON, UNLESS YOU KNOW WHAT YOU ARE DOING
-    # THIS FILE WILL BE SOURCED IN A BASH SUB-SHELL BY PLACEHOLDER_SCRIPT_NAME
-    # THE START FUNCTION WILL BE CALLED TO START THE JAIL
-
 	set -euo pipefail
 
+	# If this script is called from PLACEHOLDER_SCRIPT_NAME
+	# and DOCKER_COMPATIBLE or GPU_PASSTHROUGH is enabled
+	# then these arrays will be filled with additional args
+	SYSTEMD_RUN_ADDITIONAL_ARGS=("${@:2:$1}") && shift "$(($1 + 1))"
+	SYSTEMD_NSPAWN_ADDITIONAL_ARGS=("${@:2:$1}") && shift "$(($1 + 1))"
+
 	# Move into the directory where this script is stored (commands are relative to this directory)
 	cd "$(dirname "${BASH_SOURCE[0]}")" || exit
+	# Get the name of the jail from the directory name
 	JAIL_NAME="$(basename "$(pwd)")"
 
-    # You may add additional args to the two arrays below
-    # These args will be passed to systemd-run and systemd-nspawn in the start function
-    SYSTEMD_RUN_ADDITIONAL_ARGS=()
-    SYSTEMD_NSPAWN_ADDITIONAL_ARGS=(PLACEHOLDER_SYSTEMD_NSPAWN_ADDITIONAL_ARGS)
-
-    start() {
 	# Use mostly default settings for systemd-nspawn but with systemd-run instead of a service file
 	# https://github.com/systemd/systemd/blob/main/units/systemd-nspawn%40.service.in
 	# TODO: also compare settings for docker: https://github.com/docker/engine/blob/master/contrib/init/systemd/docker.service
@@ -145,18 +142,8 @@ template_start_script() {
 		-- \
 		systemd-nspawn --keep-unit --quiet --boot \
 		--machine="${JAIL_NAME}" --directory='./PLACEHOLDER_ROOTFS_NAME' \
+		PLACEHOLDER_SYSTEMD_NSPAWN_USER_ARGS \
 		"${SYSTEMD_NSPAWN_ADDITIONAL_ARGS[@]}"
-    }
-
-    # Call the start function if this script is executed directly (not sourced)
-    # https://stackoverflow.com/a/28776166
-    (return 0 2>/dev/null) || {
-        echo 'This script was called directly, not sourced.'
-        echo 'The jail will now start...'
-        echo 'But the DOCKER_COMPATIBLE and GPU_PASSTHROUGH settings are not considered.'
-        echo "For this to work, start the jail from PLACEHOLDER_SCRIPT_NAME."
-        start
-    }
 	# TEMPLATE END
 }
 
@@ -194,28 +181,11 @@ process_template() {
 	done < <(tail -n "+${1}" "${ABSOLUTE_SCRIPT_PATH}")
 }
 
-# Helper function which escapes and concatenates a string of arguments
-escape() {
-    local result="" spacer=""
-    # Process each argument (newline separated thanks to: xargs -n 1)
-    while IFS=$'\n' read -r arg; do
-        arg="$(declare -p arg)"
-        # Get everything after the first = character
-        arg="${arg#*=}"
-        # Append to string with leading space
-        result+="${spacer}${arg}"
-        # From now on, use a space in between elements
-        spacer=" "
-    done < <(printf "%s" "${1}" | xargs -n 1)
-
-    printf "%s" "${result}"
-}
-
 create_jail() {
-
+	# TODO: show disclaimer
 	local reply arch distro release lxc_dir_path lxc_cache_path lxc_download_script_path
-    local jail_config_path jail_start_script_name jail_start_script_path docker_compatible gpu_passthrough
+	local jail_config_path jail_start_script_path docker_compatible gpu_passthrough
-    local jail_name systemd_nspawn_additional_args
+	local jail_name systemd_nspawn_user_args
 
 	arch="$(dpkg --print-architecture)"
 	lxc_dir_path='.lxc'
@@ -308,7 +278,8 @@ create_jail() {
 		fi
 	done
 
-    # Cleanup on exit, but only once the JAIL_PATH name is known
+	# Cleanup on exit, but only once the JAIL_PATH is final
+	# Otherwise we may cleanup the wrong directory
 	trap cleanup EXIT
 
 	echo "${SCRIPT_NAME} will not install docker for you."
@@ -334,25 +305,18 @@ create_jail() {
 	echo "With incorrect flags the jail may not start."
 	echo "It's possible to correct/add/remove flags post-install."
 	echo
-    read -e -r -p "Additional flags: " SYSTEMD_NSPAWN_USER_ARGS_STRING && echo
+	read -e -r -p "Additional flags: " systemd_nspawn_user_args && echo
 	# Backslashes and colons need to be escaped for systemd-nspawn by the user:
 	# e.g. to bind mount a file called:
 	# weird chars :?\"
 	# the corresponding command would be:
 	# --bind-ro='/mnt/data/weird chars \:?\\"'
 
-    # Process the flags (read as a string) as actual command line arguments with xargs and
-    # pass these args to bash which then executes the escape function to convert the args into a properly escaped string
-    # which can be evaluated as an array declaration in the start.sh bash script
-    # https://superuser.com/a/1529316/1268213 and https://superuser.com/a/1627765
-    systemd_nspawn_additional_args="$(escape "${SYSTEMD_NSPAWN_USER_ARGS_STRING}")"
-    echo "systemd_nspawn_additional_args=${systemd_nspawn_additional_args}"
-
 	# Create directory for rootfs
 	JAIL_ROOTFS_PATH="${JAIL_PATH}/${JAIL_ROOTFS_NAME}"
 	mkdir -p "${JAIL_ROOTFS_PATH}"
 
-    jail_config_path="${JAIL_PATH}/config"
+	jail_config_path="${JAIL_PATH}/${JAIL_CONFIG_NAME}"
 	# LXC download script needs to write to this file during install
 	# but we don't need it so we will remove it later
 	touch "${jail_config_path}"
@@ -384,8 +348,6 @@ create_jail() {
 		[[ "${reply}" =~ ^([Yy]|)$ ]] && exit
 	fi
 
-    # Remove file we no longer need
-    rm -f "${jail_config_path}"
 	# Config which systemd handles for us
 	rm -f "${JAIL_ROOTFS_PATH}/etc/machine-id"
 	rm -f "${JAIL_ROOTFS_PATH}/etc/resolv.conf"
@@ -393,22 +355,29 @@ create_jail() {
 	# https://github.com/systemd/systemd/issues/852
 	printf 'pts/%d\n' $(seq 0 10) >"${JAIL_ROOTFS_PATH}/etc/securetty"
 
-    jail_start_script_name='start.sh'
+	jail_start_script_path="${JAIL_PATH}/${JAIL_START_SCRIPT_NAME}"
-    jail_start_script_path="${JAIL_PATH}/${jail_start_script_name}"
 
-    process_template "$(template_start_script)" PLACEHOLDER_DOCKER_COMPATIBLE "${docker_compatible}" PLACEHOLDER_GPU_PASSTHROUGH "${gpu_passthrough}" \
+	cat <<-EOF >"${jail_config_path}"
-        PLACEHOLDER_ROOTFS_NAME "${JAIL_ROOTFS_NAME}" PLACEHOLDER_SYSTEMD_NSPAWN_ADDITIONAL_ARGS "${systemd_nspawn_additional_args}" \
+		DOCKER_COMPATIBLE=${docker_compatible}
+		GPU_PASSTHROUGH=${gpu_passthrough}
+	EOF
+
+	chmod 700 "${jail_config_path}"
+
+	process_template "$(template_start_script)" \
+		PLACEHOLDER_ROOTFS_NAME "${JAIL_ROOTFS_NAME}" PLACEHOLDER_SYSTEMD_NSPAWN_USER_ARGS "${systemd_nspawn_user_args}" \
 		PLACEHOLDER_SCRIPT_NAME "${SCRIPT_NAME}" >"${jail_start_script_path}"
 
 	chmod 700 "${jail_start_script_path}"
 
+	# Remove the cleanup trap on exit
+	trap - EXIT
 	echo "Done creating the jail."
-    CREATE_DONE=1
 	echo
 	read -p "Start the jail now? [Y/n] " -n 1 -r reply && echo
 	# Enter accepts default (yes)
 	if [[ "${reply}" =~ ^([Yy]|)$ ]]; then
-        run_jail "${jail_start_script_path}"
+		start_jail "${JAIL_PATH}"
 	else
 		echo 'Skipped starting jail.'
 	fi
@@ -418,16 +387,6 @@ create_jail() {
 # END CREATE FUNCTIONALITY
 ##########################
 
-read -p "Create a new jail? [Y/n] " -n 1 -r reply && echo
-# Enter accepts default (yes)
-# https://stackoverflow.com/a/1885534
-if [[ "${reply}" =~ ^([Yy]|)$ ]]; then
-    create_jail
-else
-    echo "${USAGE}"
-    exit
-fi
-
 # TODO document
 # machinectl shell
 # If that doesn't work try
@@ -440,3 +399,29 @@ fi
 # machinectl login
 # TODO: recommend ssh ;)
 # TODO: create a jlmkr shell command to try the above in case machinectl shell doesn't work
+
+case "${1-""}" in
+
+'')
+	read -p "Create a new jail? [Y/n] " -n 1 -r reply && echo
+	# Enter accepts default (yes)
+	# https://stackoverflow.com/a/1885534
+	if [[ "${reply}" =~ ^([Yy]|)$ ]]; then
+		create_jail
+	else
+		echo "${USAGE}"
+	fi
+	;;
+
+create)
+	create_jail
+	;;
+
+start)
+	start_jail "${JAILS_DIR_PATH}/${2}"
+	;;
+
+*)
+	echo "${USAGE}"
+	;;
+esac