#!/bin/bash
#
# Script: clear_semaphores
#
# Usage: clear_semaphores now
#
# Description: A tool for clearing abandoned Apache semaphores
#
# Author: Adam Gomulka
#
# Changelog:
# * 06/26/2014: Adam Gomulka
# - Initial write
# * 10/20/2014: Adam Gomulka
# - Added full paths to binaries
# * 19.01.2021: Nikita Shchetinin
# - Simplified and updated following recommendations from Red Hat documentation

if [ "$(whoami)" != 'root' ]
then
	echo "You must execute this script as the root user!"
	exit 1
fi

CLEARSEM () {
if [ $(pgrep ^httpd$ | wc -l) -eq 0 ]
then
    if [ $(/bin/ipcs -s | grep apache | awk '{print$2}' | wc -l) -eq 0 ]
    then
        echo "No abandoned Apache semaphores found"
    else
        /bin/ipcrm sem $(/bin/ipcs -s | grep apache | awk '{print$2}')
    fi
else
    echo "Make sure that Apache is not running"
fi
}

HELP () {
echo "A tool for clearing abandoned Apache semaphores"
echo "usage: clear_semaphores now"
}

if [ "$1" == "now" ]
then
    CLEARSEM
else
    HELP
fi