usb-power

#!/bin/bash
#
# usb-power - Control USB ports power using uhubctl
#
# Copyright (C) 2020 Rodrigo Silva (MestreLion) <linux@rodrigosilva.com>
# License: GPLv3 or later, at your choice. See <http://www.gnu.org/licenses/gpl>
#
# TODO: add 'toggle' action, parsing uhubctl with no action to determine status
# TODO: gsettings for keyboard shortcuts
# FIXME: implement 'config' action
#------------------------------------------------------------------------------

set -Eeuo pipefail  # exit on any error
trap '>&2 echo "error: line $LINENO, status $?: $BASH_COMMAND"' ERR

#------------------------------------------------------------------------------

action=cycle
port=
location=
vendor=
message=
verbose=0

#------------------------------------------------------------------------------

url=https://github.com/mvp/uhubctl.git

myname=${0##*/}
mydir=$(dirname "$(readlink -f "$0")")
config=${XDG_CONFIG_HOME:-$HOME/.config}/usb-power.conf
destdir=${XDG_DATA_HOME:-$HOME/.local/share}/uhubctl
bindir=${XDG_BIN_HOME:-$HOME/.local/bin}
udev=/etc/udev/rules.d/52-usb-hub.rules

#------------------------------------------------------------------------------

install_package() {
	local pkg=
	local pkgs=()
	for pkg in "$@"; do
		if ! dpkg-query --show "$pkg" &>/dev/null; then pkgs+=("$pkg"); fi
	done
	if ((${#pkgs[@]})); then
		sudo apt install -y "${pkgs[@]}"
	fi
}

install_uhubctl() {
	install_package git libusb-1.0-0-dev
	if ! [[ -d "$destdir" ]]; then git clone "$url" -- "$destdir"; fi
	cd -- "$destdir"
	git reset --hard && git pull
	make
	make install sbindir="$bindir"
	exit
}

udev() {
	echo "# Added by $myname for USB hub power control via uhubctl" |
		sudo tee -- "$udev" >/dev/null
	while IFS=: read -r idVendor idProduct; do
		echo "SUBSYSTEMS==\"usb\"," \
			"ATTRS{idVendor}==\"${idVendor}\"," \
			"ATTRS{idProduct}==\"${idProduct}\", TAG+=\"uaccess\"" |
		sudo tee -a  -- "$udev" >/dev/null
	done < <(
		sudo "$bindir"/uhubctl |
		awk -F'[,[]' '/^[^ ]/ { sub(/ .*/, "", $2)
			if ($2 != prev) { print $2; prev = $2 }
		}'
	)
	sudo udevadm trigger --attr-match=subsystem=usb
	exit
}

#------------------------------------------------------------------------------

fatal()   { if (($#)); then echo "$myname: error: $@" >&2; fi; exit 1; }
message() { if (($# && verbose)); then printf '%s\n' "$@"; fi; }
argerr()  { printf "%s: %s\n" "$myname" "${1:-error}" >&2; usage 1; }
invalid() { argerr "invalid ${2:-option}: ${1:-}"; }
missing() { argerr "missing ${1:+$1 }argument${2:+ from $2}."; }

user_config() {
	local uconfig=${1:-}
	if [[ -z "$uconfig" ]]; then missing FILE --config; fi
	if ! [[ -f "$uconfig" ]]; then
		fatal "could not find config file: $uconfig"
	fi
	source "$uconfig"
}

#------------------------------------------------------------------------------

usage() {
	if [[ "${1:-}" ]] ; then exec >&2; fi
	cat <<-USAGE
	Usage: $myname [OPTIONS] [ACTION]
	USAGE
	if [[ "${1:-}" ]] ; then
		cat <<- USAGE
		Try '$myname --help' for more information.
		USAGE
		exit 1
	fi
	cat <<-USAGE

	Control USB port power

	Options:
	  -h|--help     - show this page.
	  -v|--verbose  - print more details about what is being done.

	  -c|--config FILE - Extra configuration file. Will override settings in
	                       master config file $config
	  -m|--message MSG - A message to display via notifications
	  -V|--vendor ID   - limit ACTION usage to the specified Vendor ID

	ACTION might be one of:
	  on       - turn port on
	  off      - turn port off
	  cycle    - turn port off for 2 seconds, then back on (default)
	  install  - download uhubctl from $url,
	               install it at $destdir,
	               and symlink executable to $bindir
	               May require installing dependency packages using sudo
	  config   - run 'cycle' on each USB hub port to aid creating the config file
	  udev     - generate udev rules for the USB hub port. Uses sudo

	Copyright (C) 2020 Rodrigo Silva (MestreLion) <linux@rodrigosilva.com>
	License: GPLv3 or later. See <http://www.gnu.org/licenses/gpl.html>
	USAGE
	exit 0
}

# Pre-parse for -h|--help, ignoring if after '--'
for arg in "$@"; do
	if [[ "$arg" == '--' ]]; then break; fi
	if [[ "$arg" == "-h" || "$arg" == "--help" ]]; then usage; fi
done
# Pre-parse master config file. Silently ignore if it does not exist
if [[ -f "$config" ]]; then
	source "$config"
fi
args=()
while (($#)); do
	case "$1" in
	-v|--verbose) verbose=1;;
	-V|--vendor) shift; vendor=${1:-};;
	-c|--config) shift; user_uconfig "${1:-}";;
	-m|--message) shift; message=${1:-};;
	--vendor=*) vendor=${1#*=};;
	--config=*) user_uconfig "${1#*=}";;
	--message=*) message=${1#*=};;
	-*) invalid "$1";;
	* ) args+=( "$1" );;
	esac
	shift || break
done
args+=("$@")

case ${#args[@]} in
	0) info=1;;
	1) action=${args[0]}; if [[ -z "$action" ]]; then missing ACTION; fi;;
	*) invalid "${args[1]}" ACTION;;
esac

#------------------------------------------------------------------------------

args=()

case "$action" in
	on|off|cycle) args+=(-a "$action");;
	install) install_uhubctl;;
	udev) udev;;
	config) cycle;;
	*) invalid "$action" ACTION;;
esac

if [[ "$port"     ]]; then args+=(--port     "$port"); fi
if [[ "$location" ]]; then args+=(--location "$location"); fi
if [[ "$vendor"   ]]; then args+=(--vendor   "$vendor"); fi

message uhubctl "${args[@]}"
if [[ "$message" ]]; then
	case "$action" in
		off) icon=brasero-disc-00;;
		*)   icon=brasero-disc-100;;
	esac
	notify-send --app-name "$myname"  --icon "$icon" -- "$message" || :
fi
uhubctl "${args[@]}"