#!/bin/sh

# Copyright (c) 2016 Samsung Electronics Co., Ltd All Rights Reserved
#
# 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.

# Script used to lock a file used for storing UUID.
# Prints on stdout name of the locked SDMUX.
#
# Syntax is: resource_locking.sh ${SDMUX%_*}
#
# Author: Aleksander Mistewicz <a.mistewicz@samsung.com>

SLEEP=100
while [ $SLEEP -ge 10 ]
do
    for i in $(ls "/var/tmp/uuid-${1}"* | grep -v "lock");
    do
        lockfile-create --use-pid --retry 0 "$i"
        if [ $? -eq 0 ]; then
            echo "Locked: $i" >&2
            echo "${i##*-}"
            exit
        fi
        echo "Skipped: $i" >&2
    done
    SLEEP=$((SLEEP-2))
    RAND=$(od -An -N1 -t u1 /dev/urandom)
    sleep $((RAND % SLEEP + 5))
done