#!/bin/sh
# vim: set fileencoding=utf-8 ai noet sts=8 sw=8 tw=0:
#
# Copyright © 2009 Stephen Gran <sgran@debian.org>
# Copyright © 2017 Peter Palfrader
#
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

FILE=''
INTERVAL=60
EXIT=0
ZEROFAIL=''
FOLLOW=''

set -e
set -u

usage(){
	ret=$1

	cat <<EOF
$0: usage:
	$0 <options>

	File age checker for nagios.  Will alert if the named file is
	older than the interval (interval default is 60 minutes)

	-h	This help message
	-i	Interval in minutes at which to alert
	-z	Empty files are not OK
	-L	Follow symlinks
	-f	File to check
EOF

	exit $ret
}

while getopts f:i:hzL opt ; do
	case "$opt" in
		f) FILE="$OPTARG" ;;
		i) INTERVAL="$OPTARG" ;;
		z) ZEROFAIL="1" ;;
		L) FOLLOW="-L" ;;
		h) usage 0
	esac
done
shift $(($OPTIND - 1))


if [ -z "$FILE" ] && [ "$#" = 0 ]; then
	echo "Need file argument!" >&2
	usage 3
fi

if [ -n "$FILE" ]; then
	set dummy "$FILE" "$@"
	shift
fi

msg=""
ok=""
failed=""
total=0

while [ "$#" -gt 0 ]; do
	f="$1"; shift
	total=$((total + 1))

	if [ ! -e "$f" ]; then
		msg="${msg}state file $f is missing or unreadable\n"
		EXIT=2
		failed="$f $failed"
	elif [ -n "$ZEROFAIL" ] && ! [ -s "$f" ]; then
		msg="${msg}state file $f is empty\n"
		EXIT=2
		failed="$f $failed"
	elif [ "$(( $( date +%s ) - $(stat $FOLLOW -c %Y "$f") ))" -gt "$(( $INTERVAL * 60 ))" ]; then
		msg="${msg}state file $f is older than $INTERVAL minutes (updated on $(stat $FOLLOW -c %y "$f"))\n"
		EXIT=2
		failed="$f $failed"
	else
		msg="${msg}state file $f OK: updated on $(stat $FOLLOW -c %y "$f")\n"
		ok="$f $ok"
	fi
done

if [ "$total" = 1 ]; then
	echo -n $msg
else
	if [ -n "$failed" ]; then
		echo -n "FAIL: $failed "
	fi
	if [ -n "$ok" ]; then
		echo -n "OK: $ok "
	fi
	echo
	echo -n $msg
fi
exit $EXIT