#!/bin/bash

# check_rpi_update - check for available firmware upgrades on a Raspberry Pi 2
# (Model B) (https://www.raspberrypi.org/) prerequisites: make sure you have
# NRPE up and running, so you can call this script from your remote
# nagios/icinga instance.
#
# check goes CRITICAL, if there are new commits available in the
# Raspberry Pi firmware repository.

EXIT=3
MESSAGE="UNKNOWN"
RPI_BINARY_FAIL=0

# do not auto-update the "rpi-update" script due to invoking the monitoring
export UPDATE_SELF=0

# do not suggest to take action (suppress yes/no dialogue)
export JUST_CHECK=1

RPI_UPDATE_BINARY=$(command -v rpi-update)
if [ -z "$RPI_UPDATE_BINARY" ] || [ ! -x "$RPI_UPDATE_BINARY" ]; then
	RPI_BINARY_FAIL=1
fi

if [[ "$RPI_BINARY_FAIL" -eq "1" ]]; then
        MESSAGE="UNKNOWN - 'rpi-update' is not availabe or not executable. Please make sure to install 'rpi-update'. For further information, see https://github.com/Hexxeh/rpi-update/blob/master/README.md."
        EXIT=3
else
	NEW_COMMITS_AVAILABLE=$(rpi-update | grep ^Commit:\  | wc -l)
	if [[ "$NEW_COMMITS_AVAILABLE" -eq "0" ]]; then
		MESSAGE="OK - there are no upgrades available."
		EXIT=0
	else
		MESSAGE="CRITICAL - There are $NEW_COMMITS_AVAILABLE new commits to the Raspberry Pi Firmware."
		EXIT=2
	fi
fi

echo $MESSAGE
exit $EXIT