#!/bin/bash

# script to shutdown a system running buildd in a controlled way

# Copyright (c) 2009 Peter Palfrader <peter@palfrader.org>
#
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

set -e
set -u


usage() {
	echo "Usage: $0 [-h] <reason>" >&2
	echo "        -h is for halt, not for help"
	exit 3
}

halt=0
if [ "${1:-""}" == '-h' ] ; then
	halt=1
	shift
fi

if [ "$#" != 1 ]; then
	usage
fi
reason="$1"

touch_stuff() {
	local user="$1"
	local home=$(getent passwd "$user" | awk -F: '{print $6}')

	if ! test -e "$home"/NO-DAEMON-PLEASE; then
		if [ -e "$home"/build/buildd.pid ] ; then
			echo "Touching ${home}/NO-DAEMON-PLEASE ${home}/EXIT-DAEMON-PLEASE"
			sudo -u "$user" touch "$home"/NO-DAEMON-PLEASE "$home"/EXIT-DAEMON-PLEASE
			sudo -u "$user" sh -c "echo waiting-for-clean-shutdown > '${home}/'NO-DAEMON-PLEASE"
			sudo chgrp -v adm "$home"/NO-DAEMON-PLEASE

			echo "Sending HUP to $user:buildd"
			sudo -u "$user" kill -HUP "$(sudo cat "${home}"/build/buildd.pid)"
		else
			echo "$user: no-daemon-please does not exist, but there is no buildd.pid file either"
			if pgrep -u "$user" -x buildd ; then
				echo "But there is a buildd running.  Bad?"
				exit 3
			fi
		fi
	else
		echo "no-daemon-please already exists"
	fi
}


wall_counter=0
maybe_wall() {
	wall_counter=$((wall_counter-1))
	if [ "$wall_counter" -le 0 ]; then
		if [ "$halt" = 1 ]; then
			echo "System will halt for $reason when buildd has stopped" | wall
		else
			echo "System will reboot for $reason when buildd has stopped" | wall
		fi
		wall_counter=720
	fi
}

buildd_wait_and_reboot() {
	echo -n "Waiting for buildd to shut down"

	while test -e ~buildd/build/buildd.pid  ||  test -e ~buildd2/build/buildd.pid; do
		echo -n "."
		sleep 5
		maybe_wall
	done
	echo

	if pgrep -u buildd -x buildd || pgrep -u buildd2 -x buildd; then
		echo "pidfile is gone, but buildd process still runs"
		while pgrep -u buildd -x buildd ; do
			echo -n "."
			sleep 5
			maybe_wall
		done
		echo
	fi

	if grep 'waiting-for-clean-shutdown' ~buildd/NO-DAEMON-PLEASE > /dev/null; then
		sudo -u buildd sh -c 'echo delete-on-boot > ~buildd/NO-DAEMON-PLEASE'
	fi
	if grep 'waiting-for-clean-shutdown' ~buildd2/NO-DAEMON-PLEASE > /dev/null; then
		sudo -u buildd2 sh -c 'echo delete-on-boot > ~buildd2/NO-DAEMON-PLEASE'
	fi
	if [ "$halt" = 1 ]; then
		/sbin/shutdown -h 1 "$reason"
	else
		/sbin/shutdown -r 1 "$reason"
	fi
}

if [ "`id -u`" != 0 ]; then
	echo "This probably wants running as root" >&2
	exit 3
fi
if ! id buildd > /dev/null 2>&1; then
	echo "Is there a buildd user?" >&2
	exit 3
fi
if ! [ -d ~buildd ]; then
	echo "No ~buildd?" >&2
	exit 3
fi

touch_stuff buildd
[ -d ~buildd2 ] && touch_stuff buildd2

buildd_wait_and_reboot