#!/bin/sh

# Copyright (C) 2007 Google Inc.
#
# 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 2 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, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
# 02110-1301, USA.

set -e

. common.sh

TMPDIR=`mktemp -d` || exit 1
trap "umount $TMPDIR; rmdir $TMPDIR" EXIT

# If it's not a block device try to mount it via loopback device.
# This is needed for file disks.
MOUNT_OPTIONS=""
if [ ! -b $blockdev ]; then
  MOUNT_OPTIONS="$MOUNT_OPTIONS -o loop"
fi
mount $MOUNT_OPTIONS $blockdev $TMPDIR

HNAME="$TMPDIR/etc/hostname"
MNAME="$TMPDIR/etc/mailname"

# for hostname, we raise and error if the old hostname is not what we
# expect
OLD_HNAME="`cat $HNAME`"
if [ "$OLD_HNAME" = "$old_name" ]; then
	echo $instance > $HNAME
else
	log_error "Cannot rename from $old_name to $instance:"
	log_error "Instance has a different hostname ($OLD_HNAME)"
	exit 1
fi

# for mailname, we rename only if it has the old name, otherwise we
# ignore it (and assumme that it's a customized name)
if [ "`cat $MNAME`" = "$old_name" ]; then
	echo $instance > $MNAME
fi

umount $TMPDIR
rmdir $TMPDIR
trap - EXIT

exit 0