#!/bin/bash

#Copyright 2012 Citrix Systems, Inc. Licensed under the 
#Apache License, Version 2.0 (the "License"); you may not use this
#file except in compliance with the License.  Citrix Systems, Inc.
#reserves all rights not expressly granted by 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.

LANG="C"
export LANG

usage() {
    echo "$0 [ -p <pidfile> ]" >&2
    exit 1
}

# Parse command line opts
while [ $# -ne 0 ] ; do
    arg="$1"
    shift
    case "$arg" in
        "-p")
            [ $# -eq 0 ] && usage
            pidfile="$1"
            shift
            mkdir -p "$(dirname "$pidfile")"
            echo $$ > "$pidfile"
            ;;
        *)
            usage
            ;;
    esac
done

XE_UPDATE_GUEST_ATTRS=${XE_UPDATE_GUEST_ATTRS:-/usr/sbin/xe-update-guest-attrs}
XE_DAEMON_RATE=${XE_DAEMON_RATE:-60}                    # run once a minute by default
XE_MEMORY_UPDATE_DIVISOR=${XE_MEMORY_UPDATE_DIVISOR:-2}  # update mem stats 1/2 as often by dflt

# Delete xenstore cache following each reboot
rm -rf /var/cache/xenstore

MEMORY_UPDATE_COUNTER=0
while true ; do 
    if [ ${MEMORY_UPDATE_COUNTER} -eq 0 ] ; then
	MEMORY=--memory
	MEMORY_UPDATE_COUNTER=${XE_MEMORY_UPDATE_DIVISOR}
    else
	MEMORY=
    fi
    MEMORY_UPDATE_COUNTER=$((${MEMORY_UPDATE_COUNTER} - 1))
    ${XE_UPDATE_GUEST_ATTRS} ${MEMORY}

    sleep ${XE_DAEMON_RATE}
done