#!/bin/bash
#------------------------------------------------------------------------------
#  cl-builder
#  Copyright ©2009 Mir Calculate Ltd.
#
#  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 3 of the License, or
#  (at your option) any later version.
#
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
#  GNU General Public License for more details.
#
#  You should have received a copy of the GNU General Public License
#  along with this program. If not, see <http://www.gnu.org/licenses/>.
#------------------------------------------------------------------------------

# выбор строки перемонтирования разделов в зависимости от используемого модуля
BUILDER=/mnt/builder
if [[ -n `mount | grep " / type aufs"` ]];
then
	REMOUNT="mount -t aufs -o remount,br:/ none /"
	REMOUNTBUILDER="mount -t aufs -o remount,br:/ none $BUILDER"
else
	REMOUNT="mount -t unionfs -o remount,dirs=/ unionfs /"
	REMOUNTBUILDER=":"
fi
TIMERUN=`python -c "import time;print str(time.time())[:10]"`
EMERGELOG=${BUILDER}/var/log/emerge.log
TAILEMERGELOG="tail -f ${EMERGELOG}"

#------------------------------------------------------------------------------
# Обновление Unionfs в течение сборки пакетов
#------------------------------------------------------------------------------
watching() {
	$TAILEMERGELOG |
	while read line;
	do
		if [ `echo "$line" | awk -F: '{print $1;}'` -ge $TIMERUN  ] &&
		   [ "`echo "$line" | grep -e "unemerge success" -e "completed emerge"`" ]
		then
			$REMOUNT &>/dev/null
		fi
	done
}

#------------------------------------------------------------------------------
# Монтируем ресурсы
#------------------------------------------------------------------------------
mountres() {
	mount -o bind /usr/calculate/share ${BUILDER}/usr/calculate/share &&
	mount -t proc none ${BUILDER}/proc &&
	mount -o bind /dev ${BUILDER}/dev &&
	mount -o bind /dev/pts ${BUILDER}/dev/pts && return 0

	return 1
}

#------------------------------------------------------------------------------
# Выполним emerge
#------------------------------------------------------------------------------
runchroot() {
	touch $EMERGELOG
	watching & 2>/dev/null
	chroot $BUILDER /bin/bash --rcfile /usr/calculate/install/config/chroot.rc
	WATCHINGPID=`ps axo pid,cmd | sed -nr "s|^\s*([0-9]+)\s+${TAILEMERGELOG}.*|\1|p"`
	[ "${WATCHINGPID}" ] && kill -9 $WATCHINGPID &>/dev/null
	$REMOUNT &>/dev/null
}

#------------------------------------------------------------------------------
# Отмонтируем ресурсы
#------------------------------------------------------------------------------
umountres() {
	# перебираем строку в обратном порядке
	MOUNTDIRS=`mount | grep -Po "${BUILDER}/[^ ]+" | sed "{N;s/\n/ /}"`
	for MOUNTDIR in $( echo $MOUNTDIRS | rev )
	do 
		umount $(echo $MOUNTDIR | rev) || exit
	done
}


#------------------------------------------------------------------------------
# Выполним проверки
#------------------------------------------------------------------------------
checkrun() {
	if [[ `/usr/bin/id -u` -ne 0 ]]
	then
		echo "Only root can perform system building."
		exit;
	fi
	#не запустим если загрузка не в Scrach режиме
	if ! mount | grep /mnt/scratch &>/dev/null
	then
		echo "This program only works in the system, installed by Calculate with the option '--build'."
		exit;
	fi

	#не запустим второй раз
	if mount | grep "/dev/pts on /mnt/builder/dev/pts " &>/dev/null
	then
		if [ `ps ax | grep -v grep | grep -c "/bin/bash /usr/bin/cl-builder"` -gt 3 ];
		then
			echo "This program is already run."
			exit;
		else
			umountres
		fi
	fi

	#не запустим из chroot
	if [ `mount | grep -c "devpts on /dev/pts "` -ne 1 ];
	then
		echo "This program can't be run from Scratch layer."
		exit;
	fi
}

#------------------------------------------------------------------------------
# Выполним предварительные настройки
#------------------------------------------------------------------------------
configure() {
	# Перенесем resolv.conf
	if [ -f /etc/resolv.conf ]
	then
		mkdir -p ${BUILDER}/etc
		cp /etc/resolv.conf  ${BUILDER}/etc/
	fi
}

checkrun
configure
$REMOUNTBUILDER &>/dev/null
mountres && runchroot
umountres