#!/bin/bash
#------------------------------------------------------------------------------
#  cl-builder
#  Copyright ©2009 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 $BUILDER"
else
	REMOUNT="mount -t unionfs -o remount,dirs=/ unionfs /"
	REMOUNTBUILDER=":"
fi
TIMERUN=`date +%s`
EMERGELOG=${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 /var/calculate/remote ${BUILDER}/var/calculate/remote
	mount -t proc none ${BUILDER}/proc && mount -o bind /dev ${BUILDER}/dev &&
	mount -t sysfs none ${BUILDER}/sys &&
	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

ROOTDIR=/
UPDATE_DIRS="/boot /lib/modules /lib/firmware"
#------------------------------------------------------------------------------
# Ask: whether to replace the old file
#------------------------------------------------------------------------------
ask_replace() {
	[[ $REPLACE_ANSWER == "yes" ]] && return 0
	[[ $REPLACE_ANSWER == "no" ]] && return 1
	local destfile=$1
	echo "File '$destfile' in builder is newer than in workspace"
	local line
	while true
	do
		echo -n "Do you want replace old file (Yes/No/All/None):"
		read line <&1
		case $line in
			All|all) REPLACE_ANSWER=yes;return 0;;
			None|none) REPLACE_ANSWER=no;return 1;;
			Y*|y*) return 0 ;;
			N*|n*) return 1 ;;
		esac
	done
}

#------------------------------------------------------------------------------
# Compare modify time of the first and second file
#------------------------------------------------------------------------------
test_newer() {
	# [[ file1 -nt file2 ]] not correct work with symbolic link, because
	# get modify time of target file
	if [[ -L $1 || -L $2 ]]
	then
		[[ `stat -c %Y $1` -gt `stat -c %Y $2` ]]
	else
		[[ $1 -nt $2 ]]
	fi
}

#------------------------------------------------------------------------------
# Compare modify time, ask user for update and update file
#------------------------------------------------------------------------------
try_update_file() {
	[[ -e $2 || -L $2 ]] && test_newer $1 $2 && 
		ask_replace $2 && cp -P $1 $2
}

#------------------------------------------------------------------------------
# Find in first directory files and symbolic links with modify time great than
# same files in the second directory
#------------------------------------------------------------------------------
update_from_builder() {
	basesrc=${1%/}
	basedest=${2%/}
	shift 2
	for place in $*
	do
		src=$basesrc/${place#/}
		dest=$basedest/${place#/}
		find $src -type f -o -type l |
		while read srcfile;
		do
			dstfile=${dest}/${srcfile#${src}/}
			try_update_file $srcfile $dstfile
		done
	done
}

update_from_builder $BUILDER $ROOTDIR $UPDATE_DIRS