#!/sbin/runscript
# Copyright 1999-2009 Gentoo Foundation
# Distributed under the terms of the GNU General Public License v2
# $Header: $

SQFS_DIRNAME=/var/img
SQFS_CUR="$SQFS_DIRNAME/kernel.sqfs"
SQFS_NEW="$SQFS_DIRNAME/kernel-current.sqfs"
SQFS_OLD="$SQFS_DIRNAME/kernel-old.sqfs"
[ ! $KERNDIR ] && KERNDIR="/depo/kernel"
DEF_RW="/dev/shm/.kernel-rw"

depend() {
        need localmount
}

start() {
        ebegin "Mounting read-only kernel squashfs image"
        [ -f $SQFS_CUR ] || {
                eend 1
                eerror "No squashfs image in $SQFS_CUR. Create image first!"
                einfo "You may use 'mksquashfs $KERNDIR $SQFS_CUR -no-duplicates' for it"
                return 1
        }
        mount -rt squashfs -o loop,nodev,noexec $SQFS_CUR $KERNDIR
        retval=$?
        eend $retval
        [ $retval -ne 0 ] && return $retval

        ebegin "Mounting read-write kernel image with unionfs (aufs2)"
        if [ ! $KERNEL_RW ]
        then
                einfo "  mounted in tmpfs (actually RAM)"
                KERNEL_RW="${DEF_RW}"
        fi
        [ -d $KERNEL_RW ] || mkdir -p $KERNEL_RW
        chmod 777 $KERNEL_RW
        mount -t aufs -o nodev,noexec,dirs=$KERNEL_RW=rw:$KERNDIR=ro portAufs $KERNDIR
        eend $?
}

stop() {
        ebegin "Updating kernel image"
        [ ! $PORTAGE_RW ] && PORTAGE_RW="${DEF_RW}"
        if [ ! -z `ls -A $PORTAGE_RW | grep -v '.wh..wh.' | head -n1` ]
        then
                einfo "  Syncing the image"
                mv -f $SQFS_NEW $SQFS_OLD
                mksquashfs $KERNDIR $SQFS_NEW -comp lzo -no-duplicates 2>/dev/null
                retval=$?
                ln -sf $SQFS_NEW $SQFS_CUR
        else
                einfo "  Nothing to do"
                retval=0
        fi
        eend $retval

        ebegin "Unmounting kernel"
        umount -t aufs  $KERNDIR
        umount -t squashfs $KERNDIR
        rm -rf $KERNEL_RW
        eend 0
}