#!/usr/bin/env bash
#
#
# Univention Nagios Plugin
#  check_univention_nscd: check if nscd is bound to its socket.
#
# Copyright 2017 Univention GmbH
#
# http://www.univention.de/
#
# All rights reserved.
#
# The source code of this program is made available
# under the terms of the GNU Affero General Public License version 3
# (GNU AGPL V3) as published by the Free Software Foundation.
#
# Binary versions of this program provided by Univention to you as
# well as other copyrighted, protected or trademarked materials like
# Logos, graphics, fonts, specific documentations and configurations,
# cryptographic keys etc. are subject to a license agreement between
# you and Univention and not subject to the GNU AGPL V3.
#
# In the case you use this program under the terms of the GNU AGPL V3,
# the program is provided 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 Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public
# License with the Debian GNU/Linux or Univention distribution in file
# /usr/share/common-licenses/AGPL-3; if not, see
# <http://www.gnu.org/licenses/>.
#
#

VERSION="1.00"
PROGNAME=`/usr/bin/basename $0`

STATE_OK=0
STATE_WARNING=1
STATE_CRITICAL=2
STATE_UNKNOWN=3

get_state_string() {
	if [ "$1" = "$STATE_OK" ] ; then
		STATE_STRING="OK"
	elif [ "$1" = "$STATE_WARNING" ] ; then
		STATE_STRING="WARNING"
	elif [ "$1" = "$STATE_CRITICAL" ] ; then
		STATE_STRING="CRITICAL"
	else
		STATE_STRING="UNKNOWN"
    fi
}

print_revision() {
    echo "$PROGNAME: version $VERSION"
}

print_usage() {
    echo "Usage: $PROGNAME --help"
    echo "Usage: $PROGNAME --version"
    echo "Usage: $PROGNAME"
}

print_help() {
    print_revision
    echo ""
    print_usage
}

while test -n "$1"; do
    case "$1" in
        --help)
            print_help
            exit $STATE_OK
            ;;
        -h)
            print_help
            exit $STATE_OK
            ;;
        --version)
            print_revision
            exit $STATE_OK
            ;;
        -V)
            print_revision
            exit $STATE_OK
            ;;
    esac
    shift
done

nscd_socket="/var/run/nscd/socket"

if [ ! -S $nscd_socket ]; then
	state=$STATE_CRITICAL
	get_state_string $state
	echo "${STATE_STRING}: no nscd socket found! nscd not running?"
	exit $state
fi

pids_on_nscd_socket=$(fuser "$nscd_socket" 2>/dev/zero)
RET=$?
if (( $RET != 0 )); then
	fuser_error=$(fuser "$nscd_socket" 2>&1)
	if [[ "$fuser_error" != "" ]]; then
		state=$STATE_UNKNOWN
		get_state_string $state
		echo "${STATE_STRING}: fuser command failed"
		exit $state
	fi
fi

nscd_processes_on_nscd_socket=0
for pid in $pids_on_nscd_socket; do
	process_path=$(readlink /proc/"$pid"/exe)
	if (( $? != 0 )); then
		#Process died?
		continue
	fi
	process_name=$(basename "$process_path")
	if [[ "$process_name" == "nscd" ]]; then
		let nscd_processes_on_nscd_socket++
	else
		state=$STATE_CRITICAL
		get_state_string $state
		echo "${STATE_STRING}: Unknown program: \""$process_name"\" bound to nscd socket."
		exit $state
	fi
done

if (( $nscd_processes_on_nscd_socket == 1 )); then
	state=$STATE_OK
	get_state_string $state
	echo "${STATE_STRING}: only one instance of nscd running."
	exit $state
elif (( $nscd_processes_on_nscd_socket > 1 )); then 
	state=$STATE_WARNING
	get_state_string $state
	echo "${STATE_STRING}: more than one instance of nscd bound to nscd socket."
	exit $state
elif (( $nscd_processes_on_nscd_socket == 0 )); then
	state=$STATE_CRITICAL
	get_state_string $state
	echo "${STATE_STRING}: no instance of nscd bound to nscd socket. nscd might have crashed."
	exit $state
fi

state=$STATE_CRITICAL
get_state_string $state
echo "${STATE_STRING}: PLUGIN FAILED"
exit $state
