#!/bin/bash
# CheckKernel checks if Kernel was updated and not aktivated (rebooted)
#
# (c) GPL by Ulf Bartholomäus ub1x@gmx.net
VERSION="$( basename $0 ) Version 0.2.4 from 02.11.2021"
#
# Input:        1 parameter optional ("-d" = debug and "-v" = verbose / "-D" = Distro only / "-DV" = Distro and release only / "-K" = running KernelVerion / "-N" = New Kernel Version)
# Output:       text messages and a kdialog if this is installed
# Returnvalue:	0 if Kernel OK and 10 if Kernel is changed
#
#
# Changes:
#	0.2.4:		Change way to collect Distro Name from /etc/os-releas (if empty - provide old info)
#	0.2.3:		Fix error => update in case only one Kernel is avaialble
#	0.2.2:		Fix error => new Kernel update: replace initrd with vmlinuz check
#	0.2.1:		added -D -K and -N option
#               Fixed error and exit with more than one /boot/initrd-* file
#	0.2.0:		InitKernel und VmlzKernel entfernt, 
#               [ $( ls -1 /boot/ | grep initrd- | wc -l ) -gt 1 ] && echo "** Error" || ls -1 /boot/ | grep initrd- | cut -d '-' -f 2,3,4
#               Some small changes and simplifications
#	0.1.9:		InitKernel erneut angepasstsys
#	0.1.8:		"==" -> "=" sowie kleinere Shönheitskorrekturen - sowie InitKernel mit awk statt cut
#	0.1.7:		remove "CheckKernel.sh: Zeile 33: lsb_release: Kommando nicht gefunden." 
#			and => -d = debaug
#	0.1.6:		if "lsb_release" not available use "cat /etc/*-release" info
#	0.1.5:		Fix trouble if InitKernel is empty
#	0.1.4:		Fix some errors
#	0.1.3:		Fix running and new kernel are equal but shown as different
#	0.1.2:		Remove "initrd-" from InitKernel
#	0.1.1:		Add Kernel Info in kdialog
#	0.1.0:		exchange some direct calls against definition
#				add check if new Kernel is in GRUB Config file
#	0.0.7:		read Kernel version from menu.lst
#	0.0.6:		add verbose mode
#	0.0.5:		syslog messages
#	0.0.4:		returnvalue if Kernel is changed is 10
#	0.0.3:		hostname in kdialog title
#	0.0.2:		kdialog output
#	0.0.1:		generation
#

DEBUG=""			# Debug mode ="1"
MyDistro=""			# Name of the Distro
MyDstVer=""			# Distro Version info
MyKernel=""			# Running Kernel Version
InitKernel=""		# Newest Kernel at initrd

if [ $# -gt 0 ] && [ "$1" = "-d" ] ; then
    DEBUG="1"
    echo -e "\t<${VERSION}>"
    shift
fi

if [ -e /etc/os-release ]; then
	MyDistro="$( grep PRETTY_NAME /etc/os-release )"
	MyDistro="${MyDistro/*=\"/}" # remove first string till ="
	MyDistro="${MyDistro/\"*/}" # remove "
	MyDstVer="$( grep VERSION_ID /etc/os-release )"
	MyDstVer="${MyDstVer/*=\"/}" # remove first string till ="
	MyDstVer="(${MyDstVer/\"*/})" # remove "
fi

if [ -z "${MyDistro}" ] && [ -e /proc/version ]; then
	MyDistro="$( cat /proc/version )"
	MyDistro="${MyDistro/*;/}" # remove first string till ";"
	MyDistro="${MyDistro/)*/}" # remove anything behind ")"
	MyDistro="${MyDistro/# /}" # remove blanks in the beginning
    echo -n "Version ${MyDistro} | "
fi

if [ $# -gt 0 ] && [ "$1" = "-D" ] ; then
    echo "${MyDistro}"
    exit
fi

if [ $# -gt 0 ] && [ "$1" = "-DV" ] ; then
    echo "${MyDistro} ${MyDstVer}"
    exit
fi

if [ $# -gt 0 ] && [ "$1" = "-V" ] ; then
    echo "${MyDstVer}"
    exit
fi

MyKernel="$( uname -r )"

if [ $# -gt 0 ] && [ "$1" = "-K" ] ; then
    echo "${MyKernel}"
    exit
fi

InitKernel="$( ls -1tr /boot/ | grep 'vmlinuz-' )"
if [ -n "${InitKernel}" ] ; then
    InitKernel="${InitKernel/*vmlinuz-/}"
fi

if [ $# -gt 0 ] && [ "$1" = "-N" ] ; then
    echo "${InitKernel}"
    exit
fi


if [ "${MyKernel}" = "${InitKernel}" ] ; then 
  if [ $# -gt 0 ] && [ "$1" = "-v" ] ; then
	echo -e "\t*** $( date "+%X / %d.%m.%Y" ) \tDistro: ${MyDistro} ${MyDstVer} \tKernel: ${MyKernel} \t*** Kernel OK ***"
  else
	echo "*** Kernel OK  (${MyKernel})"; 
  fi
else 
  if ( [ $# -gt 0 ] && [ "$1" = "-v" ] ) ; then
	echo -e "\t*** $( date "+%X / %d.%m.%Y" ) \tDistro: ${MyDistro} ${MyDstVer} \tKernel: ${MyKernel} \t*** NEW Kernel ${InitKernel}!!! ***"
  else
	MsgTxt="*** Kernel Updated from ${MyKernel} to ${InitKernel}! => please reboot"
	echo "${MsgTxt}";
	logger -t $( basename $0 ) "${MsgTxt}"
	if [ $# -eq 0 ] && [ -e $( which kdialog 2>> /dev/null ) ] ; then
	  kdialog --title "*** $( hostname ) ***" --error "${MsgTxt}"  >> /dev/null 2>> /dev/null
	fi
  fi
  exit 10
fi