#!/bin/sh

PATH=/usr/sbin:/sbin:/usr/bin:/bin
LANG=C

set -e

activate_harddisk(){
    if ( ! lsmod | grep -q sbp2 ); then
	for d in ieee1394 ohci1394 sbp2; do
	    modprobe $d
	done
    fi
    if ( ! grep -q Vendor: /proc/scsi/scsi ); then
	scsiadd -a 0
    fi
}

deactivate_harddisk(){
    scsiadd -r 0
}

mount_harddisk(){
    if ( ! mount | grep -q /mnt ); then
	if ( grep -q Vendor: /proc/scsi/scsi ); then
	    fsck -s /dev/sda1
	    mount /dev/sda1 /mnt
	else
	    echo "Harddisk has not been acitvated." 1>&2
	    exit 1
	fi
    fi
}

umount_harddisk(){
    if ( mount | grep -q /mnt ); then
	umount /mnt
    fi
}

selections(){
    dpkg --get-selections
}

deborphan_txt(){
    deborphan -L
}

iptables_txt(){
    ( iptables-save | egrep -v '^[#:]' ) || true
}

rotate(){
    old=/mnt/backup/`echo $1|sed s/_/./g`
    new=$1.$$
    $1 > $new
    if [ -f $old ]; then
	if ( cmp -s $old $new ); then
	    rm -f $new
	else
	    savelog -c 5 $old
	    mv $new $old
	fi
    else
    	mv $new $old
    fi
}

do_backup(){
    if [ -d /mnt/backup ]; then
	rotate selections
	rotate deborphan_txt
	rotate iptables_txt
	rdiff-backup /etc /mnt/backup/etc
	rdiff-backup --exclude /home/lost+found /home /mnt/backup/home
	rdiff-backup /usr/local /mnt/backup/usr/local
	rdiff-backup /var/backups /mnt/backup/var/backups
	rdiff-backup --force --remove-older-than 7D /mnt/backup/var/backups
    fi
}

if [ "$1"x = x ]; then
    activate_harddisk
    mount_harddisk
    do_backup
    umount_harddisk
    deactivate_harddisk
else
    case "$1" in
	-a|--activate)
	    activate_harddisk
	    ;;
	-m|--mount)
	    activate_harddisk
	    mount_harddisk
	    ;;
	-u|--umount)
	    umount_harddisk
	    ;;
	-d|--deactivate)
	    umount_harddisk
	    deactivate_harddisk
	    ;;
	*)
	    cat <<EOF
Usage: $0
  Put backups of /etc and /home to a disk.

Usage: $0 [option]
  -a, --activate	Activate a disk.
  -d, --deactivate	Deactivate a disk.
  -m, --mount		Mount a disk.
  -u, --umount		Unmount a disk.
  -h, --help		Print this message.
EOF
	;;
    esac
fi