#!/bin/bash
# Licensed to the Apache Software Foundation (ASF) under one
# or more contributor license agreements.  See the NOTICE file
# distributed with this work for additional information
# regarding copyright ownership.  The ASF licenses this file
# to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance
# with the License.  You may obtain a copy of the License at
#
#   http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing,
# software distributed under the License is distributed on an
# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
# KIND, either express or implied.  See the License for the
# specific language governing permissions and limitations
# under the License.

#set -x

usage() {
  printf "Usage: %s [vhd file in secondary storage] [template directory in secondary storage] \n" $(basename $0)
}

cleanup()
{
  if [ ! -z $snapshotdir ]; then
    umount $snapshotdir
    if [ $? -eq 0 ];  then
      rmdir $snapshotdir
    fi
  fi
  if [ ! -z $templatedir ]; then
    umount $templatedir
    if [ $? -eq 0 ];  then
      rmdir $templatedir
    fi
  fi
}

if [ -z $1 ]; then
  usage
  echo "2#no vhd file path"
  exit 0
else
  snapshoturl=${1%/*}
  vhdfilename=${1##*/}
fi

if [ -z $2 ]; then
  usage
  echo "3#no template path"
  exit 0
else
  templateurl=$2
fi

snapshotdir=/var/run/cloud_mount/$(uuidgen -r)
mkdir -p $snapshotdir
if [ $? -ne 0 ]; then
  echo "4#can't make dir $snapshotdir"
  exit 0
fi

mount -o tcp $snapshoturl $snapshotdir
if [ $? -ne 0 ]; then
  rmdir $snapshotdir
  echo "5#can not mount $snapshoturl to $snapshotdir"
  exit 0
fi

templatedir=/var/run/cloud_mount/$(uuidgen -r)
mkdir -p $templatedir
if [ $? -ne 0 ]; then
  templatedir=""
  cleanup
  echo "6#can't make dir $templatedir"
  exit 0
fi

mount -o tcp $templateurl $templatedir
if [ $? -ne 0 ]; then
  rmdir $templatedir
  templatedir=""
  cleanup
  echo "7#can not mount $templateurl to $templatedir"
  exit 0
fi

VHDUTIL="/opt/cloud/bin/vhd-util"

upgradeSnapshot()
{
  local ssvhd=$1
  local parent=`$VHDUTIL query -p -n $ssvhd`
  if [ $? -ne 0 ]; then
    echo "30#failed to query $ssvhd"
    cleanup
    exit 0
  fi
  if [ "${parent##*vhd has}" = " no parent" ]; then
    dd if=$templatevhd of=$snapshotdir/$templatefilename bs=2M
    if [ $? -ne 0 ]; then
      echo "31#failed to dd $templatevhd to $snapshotdir/$templatefilenamed"
      cleanup
      exit 0
    fi

    $VHDUTIL modify -p $snapshotdir/$templatefilename -n $ssvhd
    if [ $? -ne 0 ]; then
      echo "32#failed to set parent of $ssvhd to $snapshotdir/$templatefilenamed"
      cleanup
      exit 0
    fi

    rm -f $parent
  else
    upgradeSnapshot $parent
  fi
}

templatevhd=$(ls $templatedir/*.vhd)
if [ $? -ne 0 ]; then
  echo "8#template vhd doesn't exist for $templateurl"
  cleanup
  exit 0
fi
templatefilename=${templatevhd##*/}
snapshotvhd=$snapshotdir/$vhdfilename
upgradeSnapshot $snapshotvhd
cleanup
echo "0#success"
exit 0