#!/bin/bash
#
# -------------------------------------------------------------------------- #
# Copyright 2010-2016, OpenNebula Systems                                    #
#                                                                            #
# Licensed 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.                                             #
#--------------------------------------------------------------------------- #

LOCK_FILE="/var/run/one-context.lock"
CONTEXT_FILE="/tmp/context.sh"
CONTEXT_NEW="${CONTEXT_FILE}.new"
END_CONTEXT="/tmp/context.end"

function export_rc_vars
{
    if [ -f $1 ] ; then
        ONE_VARS=`cat $1 | egrep -e '^[a-zA-Z\-\_0-9]*=' | sed 's/=.*$//'`

        . $1

        for v in $ONE_VARS; do
            export $v
        done
    fi
}

function execute_scripts {
    SCRIPTS_DIR="/etc/one-context.d"
    for script in $SCRIPTS_DIR/*; do
        "$script" "$1"
    done
}

function get_new_context {
    CONTEXT_DEV=`blkid -l -t LABEL="CONTEXT" -o device`
    if [ -e "$CONTEXT_DEV" ]; then
        mount -t iso9660 -L CONTEXT -o ro /mnt
        if [ -f /mnt/context.sh ]; then
            cp /mnt/context.sh ${CONTEXT_NEW}
        fi

        echo "umount /mnt" > ${END_CONTEXT}
    elif curl -o ${CONTEXT_NEW} http://169.254.169.254/latest/user-data ; then
        echo -n ""
    elif type vmtoolsd ; then
        vmtoolsd --cmd 'info-get guestinfo.opennebula.context' | \
            openssl base64 -d > ${CONTEXT_NEW}
    fi
}

function check_context {
    if [ -s "${CONTEXT_NEW}" ]; then
        diff ${CONTEXT_FILE} ${CONTEXT_NEW} >/dev/null 2>&1 && return 1
        return 0
    else
        return 1
    fi
}

function run_context {
    cp ${CONTEXT_NEW} ${CONTEXT_FILE}

    export_rc_vars ${CONTEXT_FILE}
    execute_scripts "$1"
}

function end_context {
    if [ -e "${END_CONTEXT}" ]; then
        sh "${END_CONTEXT}"
        rm "${END_CONTEXT}"
    fi
    [ -e "${CONTEXT_NEW}" ] && rm "${CONTEXT_NEW}"
}

function adquire_lock {
    while [ -e "${LOCK_FILE}" ]; do
        sleep 1
    done

    touch "${LOCK_FILE}"
}

function release_lock {
    rm -f "${LOCK_FILE}"
}

COMMAND="$1"

adquire_lock

get_new_context
check_context && run_context "$COMMAND"
end_context

release_lock