#!/bin/bash
#
# ----------------------------------------------------------------------
#
# Description: This script can check continuously
# if certain server daemons are running. If not
# they will be restarted. A message will be mailed
# to the specified adress as defined in $MAILME.
# If $MAILME is empty, then mail will be sent to
# root. $SLEEP will set the frequency of the checks.
# The script will test for certain distributions,
# set up logging, and checks if services do not
# conflict with (x)inetd while restarting.
#
# Note: Script output is in DUTCH LANGUAGE!
# Script logic is straightforward so you could
# translate yourself.
#
# Author: Maccus
#
# Initial version: 080324-01
#
# Update: 110722-01
# - Changed redhat and debian
#   startcommands from "/etc/initdir/service start"
#   to "service service start" for better
#   compatibility.
#
# TODO: Support for more servers (DNS, Apache 1).
#
# Requires: netstat
#
# This script has been written and tested on
# Ubuntu Linux 10.04 and Debian Testing (Wheezy)
#
# ----------------------------------------------------------------------
#
# Usage: Place the script in "/usr/local/bin", do a
# "chmod +x /usr/local/bin/net-server-monitor" as root,
# and run "net-server-monitor apache2 sshd .. &" from
# the command line, or put such a line in one of your
# startup scripts. Currently supported servers are:
# apache2 proftpd samba sshd xinetd
#
# ----------------------------------------------------------------------
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License along
# with this program; if not, write to the Free Software Foundation,
# Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
#
# ----------------------------------------------------------------------
#
# Uncomment for debugging
#
# set -x

# Start script

echo -e "\n\033[1;33mSTATUS\033[0m: Script \"$(basename $0)\" is gestart...\n"

# Variabelen

# Frequentie in seconden

SLEEP="10"

# Email-adres voor waarschuwingen. Indien
# leeg gaan alle waarschuwingen naar root.

MAILME=""

# Feedback

VERBOSE="yes"

# Niet aanpassen!

SERVERS="$*"

# Ondersteunde servers. Niet aanpassen!

SUPPD_SRV="apache2 proftpd samba sshd xinetd"


# Alleen voor root

check_root () {

    if [ "${UID}" != "0" ]; then

	echo -e "Dit script kan alleen door root worden uitgevoerd! Script wordt nu afgesloten...\n"

	sleep 2

	exit 1

    fi

}


# Afhankelijkheden

check_dependencies () {

    for FILE in $* ; do

	if [ ! "$(which ${FILE} 2> /dev/null)" ]; then

	    echo -e "Bestand \"${FILE}\" niet gevonden! Installeer het pakket waarin \"${FILE}\" voorkomt en probeer het opnieuw. Script wordt nu afgesloten...\n"

	    sleep 2

	    exit 1

	fi

    done

}


# Script argumenten

check_args () {

    if [ -z "$*" ]; then

	echo -e "\033[1;31mFOUT\033[0m: Je moet een of meerdere servers als argument opgeven..."
	echo -e "Bijvoorbeeld: $0 ${SUPPD_SRV}"
	echo -e "Dit script wordt afgebroken...\n"

	sleep 5 ; exit 1

    elif [ -n "$*" ]; then

	for SRV in $* ;do

	    if ! ( echo "${SUPPD_SRV}" | grep -q "${SRV}" ); then

		echo -e "\nServer \"${SRV}\" wordt niet door dit script ondersteund."
		echo -e "Alleen servers \"${SUPPD_SRV}\" worden momenteel ondersteund."
		echo -e "\"${SRV}\" wordt verwijderd uit de argumenten lijst.\n"

		remove_arg

	    fi

	done

    fi

}


# Check distro. Alleen de meest gangbare distributies.

check_distro () {

    if [ -f "/etc/debian_version" -o -f "/etc/lsb-release" ]; then

        # Debian en Ubuntu

        INITDIR="/etc/init.d"
	DISTRO="debian"

    elif [ -f "/etc/redhat-release" -o -f "/etc/redhat_version" -o -f "/etc/fedora-release" -o -f "/etc/mandriva-release" ]; then

	# Redhat, Fedora en Mandriva

	INITDIR="/etc/rc.d/init.d"
	DISTRO="redhat"

    elif [ -f "/etc/SuSE-release" -o -f "/etc/novell-release" -o -f "/etc/sles-release" ]; then

	# SuSE

	INITDIR="/etc/init.d"
	DISTRO="suse"

    else

	echo -e "Dit script draait alleen op Debian, Fedora, Mandriva, Redhat, SuSE, of Ubuntu."
	echo -e "Voor een andere distributie kun je het script zelf aanpassen :-)"
	echo -e "Script wordt afgebroken...\n"

	sleep 5

	exit 1

    fi

}


# Ongeldige argumenten verwijderen

remove_arg () {

    SERVERS="$(echo "${SERVERS}" | sed "s|${SRV}||")"

}


# Eeuwige iteratie...

monit_servers () {

    while [ "x" = "x" ]; do

	for SRV in ${SERVERS} ; do

	    # Feedback

	    [ "${VERBOSE}" = "yes" ] && echo "Controleren of ${SRV} nog draait..."


	    # Voor het gemak

	    DATE="$(date)"
	    HOST="$(hostname -s)"


	    # Commando's per distro. Bij veranderen van ${SUPP_SRV} moeten onderstaande case statements ook aangepast worden!

	    case ${SRV} in

		apache2)    if [ "${DISTRO}" = "redhat" ]; then

				PROCESS="httpd"
				RESTARTCMD="service httpd start"

			    elif [ "${DISTRO}" = "suse" ]; then

				PROCESS="httpd2-prefork"
				RESTARTCMD="${INITDIR}/apache2 start"

			    elif [ "${DISTRO}" = "debian" -o "${DISTRO}" = "ubuntu" ]; then

				PROCESS="apache2"
				RESTARTCMD="service apache2 start"

			    fi

			    # Netstat
			    SERVICE="http"

			    ;;

		proftpd)    if [ "${DISTRO}" = "redhat" ]; then

				PROCESS="proftpd"
				RESTARTCMD="service proftpd start"

			    elif [ "${DISTRO}" = "suse" -o "${DISTRO}" = "debian" ]; then

				# Geen Proftpd voor SuSE, jammer dan.
				# Proftpd weghalen uit argumentenlijst

				remove_arg

			    elif [ "${DISTRO}" = "debian" ]; then

				PROCESS="proftpd"
				RESTARTCMD="service proftpd start"

			    fi

			    # Netstat
			    SERVICE="ftp"

			    ;;

		samba)	   if [ "${DISTRO}" = "redhat" -o "${DISTRO}" = "suse" ]; then

				PROCESS="smbd"
				RESTARTCMD="service smb start"

			    elif [ "${DISTRO}" = "debian" ]; then

				PROCESS="smbd"
				RESTARTCMD="service smbd start"

			    fi

			    # Netstat
			    SERVICE="netbios"

			    ;;

		sshd)	    if [ "${DISTRO}" = "redhat" -o "${DISTRO}" = "suse" ]; then

				PROCESS="sshd"
				RESTARTCMD="service sshd start"

			    elif [ "${DISTRO}" = "debian" ]; then

				PROCESS="sshd"
				RESTARTCMD="service ssh start"

			    fi

			    # Netstat
			    SERVICE="ssh"

			    ;;

		xinetd)	    if [ "${DISTRO}" = "redhat" ]; then

				PROCESS="xinetd"
				RESTARTCMD="service xinetd restart"

			    elif [ "${DISTRO}" = "suse" -o "${DISTRO}" = "debian" ]; then

				PROCESS="xinetd"
				RESTARTCMD="service xinetd restart"

			    fi

			    ;;

	    esac


	    # Servers die draaien onder (x)inetd niet proberen te herstarten !
	    # Deze servers worden uit argumentenlijst gehaald

 	    if [ "${SRV}" != "xinetd" ]; then

		if ( netstat -pl --inet | grep "inetd" | grep -q "${SERVICE}" ); then

		    # Feedback

		    [ "${VERBOSE}" = "yes" ] && echo "${SRV} draait onder (x)inetd en wordt overgeslagen..."

	    	    remove_arg && break

		fi

	    fi

	    # Check of de server draait

	    if ! ps -e | grep -q "${PROCESS}" ; then

    		if ${RESTARTCMD} ; then

		    # Verstuur notificatie bij sucesvolle herstart

		    echo -e "Server \"${SRV}\" op \"${HOST}\" opnieuw gestart op ${DATE}." | \
		    mail -s "Server \"${SRV}\" opnieuw gestart!" "${MAILME:=root}"

		else

		    # Verstuur waarschuwing bij mislukte herstart

		    echo -e "Server \"${SRV}\" op \"${HOST}\" kon niet worden geherstart op ${DATE}. Onderzoek de logbestanden in /var/log !" | \
		    mail -s "Kritieke Fout! Server \"${SRV}\" kon niet worden geherstart!" "${MAILME:=root}"

		    # Uitgevallen server verwijderen uit argumentenlijst
		    # om te voorkomen dat dit script eeuwig blijft 
		    # proberen om de server te herstarten

		    remove_arg

		fi

	    fi

	    # Niet te snel

	    sleep 1

	done

	# Check wordt uitgevoerd iedere $SLEEP seconden. Standaardwaard is 60 seconden.

	sleep ${SLEEP:=60}

    done

}


# Functies starten

check_root
check_dependencies netstat
check_args "$*"
check_distro
monit_servers

exit 0