#!/bin/sh
#
# trigger-rcmp: Trigger remote commands
# Copyright (c)2014-2016 Alexander Barton (alex@barton.de)
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
# Please read the file COPYING, README and AUTHORS for more information.
#

BASENAME=$(basename "$0")
NAME="$BASENAME"
RCMD_D="/usr/local/etc/rcmd.d"

PATH="$PATH:/usr/local/sbin:/usr/sbin"

do_help() {
	echo "Usage: $0 [--no-wake|-n] <rcmd> [<rcmd> [...]]" >&2
	exit 2
}

do_rcmd() {
	SYSTEM="localhost"
	IFACE="eth0"
	CMD="uptime"
	TIMEOUT="300"
	SSH_CHECKS="6"
	WAKE_DELAY="10s"
	BOOT_DELAY="1m"
	SHUTDOWN_TIME="+10"

	# Read in job/configuration file, but ignore shellcheck(1) warnings:
	# shellcheck disable=1090
	. "$cnf"

	if [ $? -ne 0 ]; then
		echo "$NAME: Failed to read \"$cnf\"!"
		return 2
	fi

	echo "$NAME: Checking system \"$SYSTEM\" ..."
	fping -c1 -q "$SYSTEM" 2>/dev/null
	if [ $? -ne 0 ]; then
		if [ -n "$NO_WAKE" ]; then
			echo "$NAME: \"$SYSTEM\" seems to be down, skipping job."
			return 9
		fi

		echo "$NAME: \"$SYSTEM\" seems to be down, wake it up ..."
		etherwake -b -i "$IFACE" "$(echo "$SYSTEM" | cut -d'.' -f1)"
		if [ $? -ne 0 ]; then
			echo "$NAME: Failed to wake \"$SYSTEM\"!" >&2
			return 3
		fi
		echo "$NAME: Waiting for \"$SYSTEM\" to respond ..."
		for i in $(seq 1 $TIMEOUT); do
			fping -c1 -q "$SYSTEM" 2>/dev/null
			[ $? -ne 0 ] || break
			sleep 1s
		done
		fping -c1 -q "$SYSTEM" 2>/dev/null
		if [ $? -ne 0 ]; then
			echo "$NAME: Failed to wake \"$SYSTEM\"!" >&2
			return 4
		fi
		sleep "$WAKE_DELAY"
		rsys_was_running=0
	else
		echo "$NAME: \"$SYSTEM\" is already alive, ok."
		rsys_was_running=1
	fi

	for i in $(seq 1 $SSH_CHECKS); do
		echo "$NAME: Checking SSH connection [publickey] ($i/$SSH_CHECKS) ..."
		if ssh -o PreferredAuthentications=publickey -q "$SYSTEM" true >/dev/null 2>&1; then
			echo "$NAME: Ok, SSH seems to be available on \"$SYSTEM\"."
			break
		fi
		echo "$NAME: SSH on \"$SYSTEM\" not ready. Waiting ..."
		sleep 10s
	done

	if [ "$rsys_was_running" -eq 0 ]; then
		echo "$NAME: \"$SYSTEM\" just started up. Delaying actions for $BOOT_DELAY ..."
		sleep "$BOOT_DELAY"
	fi

	echo "$NAME: Calling \"$CMD\" on \"$SYSTEM\" ..."
	echo

	# shellcheck disable=2029
	ssh -o PreferredAuthentications=publickey -q "$SYSTEM" "$CMD" </dev/null ; r=$?

	echo
	echo "$NAME: Remote command ended with return code $r."
	sleep 2

	if [ "$rsys_was_running" -eq 0 ]; then
		rsys_users=$(ssh -q "$SYSTEM" w | tail -n +3 | wc -l)
		if [ "$rsys_users" = "0" ]; then
			echo "$NAME: Power off \"$SYSTEM\" again ..."
			# shellcheck disable=2029
			ssh -o PreferredAuthentications=publickey -q "$SYSTEM" "sync; shutdown -hP $SHUTDOWN_TIME" >/dev/null
			if [ $? -ne 0 ]; then
				echo "$NAME: Failed to power off \"$SYSTEM\"!" >&2
				return 5
			fi
		else
			echo "$NAME: Not shutting down \"$SYSTEM\", \c"
			[ "$rsys_users" -eq 1 ] \
				&& echo "There is 1 user logged in!" \
				|| echo "There are $rsys_users users logged in!"
		fi
	else
		echo "$NAME: \"$SYSTEM\" was already alive, not shutting down."
	fi
	[ $r -eq 0 ] && return 0 || return 1
}

# Defaults
NO_WAKE=

# Check required tools
for t in fping ssh etherwake lockfile-create; do
	if ! command -v "$t" >/dev/null 2>&1; then
		echo "$NAME: Required tool \"$t\" missing, aborting!"
		exit 3
	fi
done

while [ $# -gt 0 ]; do
	case "$1" in
	  --no-wake|-n)
		NO_WAKE=1; ;;
	  --help|-*)
		do_help; ;;
	  *)
		break
	esac
	shift
done

[ $# -gt 0 ] || do_help

result=0
while [ $# -gt 0 ]; do
	cnf="$RCMD_D/$1"
	if [ ! -r "$cnf" ]; then
		echo "$NAME: Can't read \"$cnf\"!"
		r=1
	else
		echo "$NAME: Working on \"$1\" - $(date "+%Y-%m-%d %H:%M:%S")"
		NAME="$BASENAME($1)"
		lck="/run/lock/$NAME-$1.lock"
		if lockfile-create --quiet --use-pid --retry 2 --lock-name "$lck"; then
			do_rcmd "$1" ; r=$?
			echo "$NAME: Done ($r) - $(date "+%Y-%m-%d %H:%M:%S")"
			rm -f "$lck"
		else
			echo "$NAME: Failed to acquire lock file, skipping job! ($lck)"
			r=1
		fi
		NAME=$BASENAME
	fi
	[ $r -ne 0 ] && result=1
	shift
	[ $# -gt 0 ] && echo
done
exit $result