xlock

#!/bin/sh -eu


###
### Defaults
###
DEFAULT_BACKGROUND="0"
DEFAULT_SCALE="3"
DEFAULT_OVERLAY_PATH=""
DEFAULT_NOTIFY_DAEMON="dunst"
DEFAULT_MUTE="0"

###
### Credits
###
MY_VERSION="v0.1"
MY_DATE="2017-07-05"
MY_URL="https://github.com/cytopia/i3-utils"

###
### System variables
###
MY_NAME="$( basename "${0}" )"
MY_LOG_DIR="${HOME}/.log"
MY_LOG_FILE="${MY_LOG_DIR}/${MY_NAME}.err"
MY_DATE="$( date '+%Y-%m-%d' )"
MY_TIME="$( date '+%H:%M:%S' )"

if [ ! -d "${MY_LOG_DIR}" ]; then
	mkdir -p "${MY_LOG_DIR}"
fi
if [ ! -f "${MY_LOG_FILE}" ]; then
	touch "${MY_LOG_FILE}"
fi
if [ ! -w "${MY_LOG_FILE}" ]; then
	chmod u+w "${MY_LOG_FILE}"
fi



################################################################################
##
##  F U N C T I O N S
##
################################################################################

# Test if argument is an integer.
#
# @param  mixed
# @return integer	0: is int | 1: not an int
isint() {
	echo "${1}" | grep -Eq '^([0-9]|[1-9][0-9]*)$'
}


error() {
	printf "%s\n" "${1}" >&2
	printf "[%s] [%s] %s\n" "${MY_DATE}" "${MY_TIME}" "${1}" >> "${MY_LOG_FILE}"
}

print_usage() {
	echo "Usage: ${MY_NAME} [-b] [-m] [-s <1-100>] [-o <path>] [-n <name>]"
	echo "       ${MY_NAME} -h"
	echo "       ${MY_NAME} -v"
	echo
	echo "Helper script for i3lock."
	echo
	echo "  -b            (optional) Background mode."
	echo "                The whole script is put into background so that you can"
	echo "                run another script afterwards, such as system suspend/hibernat."
	echo "                The default is to run in foreground mode."
	echo
	echo "  -m            (optional) Mute sound before locking the screen."
	echo
	echo "                The whole script is put into background so that you can"
	echo "  -s <1-100>    (optional) Scale factor in percent."
	echo "                The default is 3."
	echo
	echo "  -o <path>     (optional) Path to an image to overlay onto lockscreen."
	echo "                The default is not to use an overlay image."
	echo
	echo "  -n <name>     (optional) Binary name of the notification daemon to suspend"
	echo "                while the screen is locked. It should be suspended so"
	echo "                that no notifications will be displayed while you are"
	echo "                away with a locked screen."
	echo "                The default is 'dunst'."
	echo
	echo "  -h            Show this help screen."
	echo "  -v            Show version information."
}

print_version() {
	printf "%s %s (%s) by cytopia\n" "${MY_NAME}" "${MY_VERSION}" "${MY_DATE}"
	printf "%s\n" "${MY_URL}"
}

lock_screen() {
	# 1-100%
	_scale_factor="${1}"
	# Path to overlay image
	_overlay_path="${2}"
	# i3lock foreground mode?
	_i3lock_background="${3}"

	_upscale_factor="$(( 100 * 100 / _scale_factor ))"
	_screenshot="$( mktemp --suffix='.png' )"

	# Ensure we do not abort here in case of ImageMagick error
	if command -v maim >/dev/null 2>&1; then
		echo "maim"
		maim --quality 10 --delay=0.0  "${_screenshot}.jpg"
	else
		echo "scrot"
		scrot --quality 100 --silent "${_screenshot}.jpg"
	fi
	mv "${_screenshot}.jpg" "${_screenshot}"
	convert ${_screenshot} -scale ${_scale_factor}% -scale ${_upscale_factor}% ${_screenshot}

	# Add overlay (optional)
	if [ -f "${_overlay_path}" ]; then
		# Ensure we do not abort here in case of ImageMagick error
		convert "${_screenshot}" "${_overlay_path}" -gravity center -geometry +0+0 -composite -matte "${_screenshot}"
	fi

	# Lock screen
	if [ "${_i3lock_background}" = "1" ]; then
		i3lock --show-failed-attempts --image="${_screenshot}"
	else
		i3lock --nofork --show-failed-attempts --image="${_screenshot}"
	fi
}
suspend_notify() {
	_notify_daemon="${1}"

	# Suspend notification daemon
	pkill -u "${USER}" -USR1 "${_notify_daemon}"
}
resume_notify() {
	_notify_daemon="${1}"

	# Wait until i3lock is closed (screen not locked anymore)
	while pidof i3lock >/dev/null 2>&1; do
		sleep 1
	done
	# Resume notification daemon
	pkill -u "${USER}" -USR2 "${_notify_daemon}"
}
mute_sound() {
	if ! _err="$( amixer sset 'Master' mute 2>&1 >/dev/null )"; then
		error "${_err}"
		exit 1
	fi
}


################################################################################
##
##  E N T R Y   P O I N T
##
################################################################################

BACKGROUND="${DEFAULT_BACKGROUND}"
SCALE="${DEFAULT_SCALE}"
OVERLAY_PATH="${DEFAULT_OVERLAY_PATH}"
NOTIFY_DAEMON="${DEFAULT_NOTIFY_DAEMON}"
MUTE="${DEFAULT_MUTE}"

while [ $# -gt 0 ]; do
	case "${1}" in
		-b)
			BACKGROUND="1"
			;;
		-m)
			MUTE="1"
			;;
		-s)
			shift
			if ! isint "${1}"; then
				error "Argument for -s: Is not an integer: ${1}"
				exit 1
			fi
			if [ "${1}" -lt 0 ] || [ "${1}" -gt 100 ]; then
				error "Argument for -s: Must be between 1 and 100. Specified: ${1}"
				exit 1
			fi
			SCALE="${1}"
			;;

		-o)
			shift
			if [ ! -f "${1}" ]; then
				error "Argument for -o: File does not exist: ${1}"
				exit 1
			fi
			OVERLAY_PATH="${1}"
			;;
		-n)
			shift
			NOTIFY_DAEMON="${1}"
			;;
		-h)
			print_usage
			exit 0
			;;
		-v)
			print_version
			exit 0
			;;
		*)
			error "Invalid argument supplied: ${1}"
			exit 1
			;;
	esac
	shift
done


###
### Error Checking
###
if ! command -v maim >/dev/null 2>&1; then
	if ! command -v scrot >/dev/null 2>&1; then
		error "binary 'maim' or 'scrot' not found but required."
		exit 1
	fi
fi
if ! command -v convert >/dev/null 2>&1; then
	error "binary 'convert' not found but required."
	exit 1
fi
if ! command -v i3lock >/dev/null 2>&1; then
	error "binary 'i3lock' not found but required."
	exit 1
fi
if [ "${MUTE}" = "1" ]; then
	if ! command -v amixer >/dev/null 2>&1; then
		error "binary 'amixer' not found but required when using -m option."
		exit 1
	fi
fi

# Make sure not to start another i3lock instance,
# if it is already running.
if pidof i3lock >/dev/null 2>&1; then
	error "i3lock is already running, aborting."
	exit 1
fi

# Dunst shows notifications in lock screen by default.
# In order to prevent that, we need to suspend the dunst
# process prior locking and resume after the lock process
# finishes.


# Suspend notification daemon
suspend_notify "${NOTIFY_DAEMON}"

# Mute sound if desired
if [ "${MUTE}" = "1" ]; then
	mute_sound
fi

# Lock screen foreground or background task
# depening on the command line argument
lock_screen "${SCALE}" "${OVERLAY_PATH}" "${BACKGROUND}"

# Resume notification service.
# In case of background service, the function will be brought
# into background itself and the script finishes.
# This way you can start other services after this script
# such as suspend to RAM/Disk and during wake-up, you will still
# have a locked screen with resuming notification during unlock
if [ "${BACKGROUND}" = "1" ]; then
	resume_notify "${NOTIFY_DAEMON}" &
else
	resume_notify "${NOTIFY_DAEMON}"
fi