mini_logcheck.sh

mini_logcheck.sh

#!/bin/sh
# Copyright (C) 2011  Glen Pitt-Pladdy
# Copyright (C) 2019  Gabriel Nyman
#
# 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
#
# 
# See: http://www.pitt-pladdy.com/blog/_20110501-112534_0100_Log_checker_mini_logcheck_for_OpenWrt/

# mail configuration
RECIPIENT=you@yourdomain

# general paths
LOG=/var/log/messages
LOGPOS=$LOG.pos
RULES=/etc/logcheck.ignore.d

# temporary files
TMPTAIL=/tmp/tmplog_`hexdump -n 8 -e \"%x\" /dev/urandom`
TMPRULES=/tmp/tmprules_`hexdump -n 8 -e \"%x\" /dev/urandom`
TMPMESSAGE=/tmp/tmpmessage_`hexdump -n 8 -e \"%x\" /dev/urandom`


# read in existing position if available
position=1
inode=`ls -i $LOG | cut -d' ' -f1`
if [ -f $LOGPOS ]; then
	position=`cat $LOGPOS | cut -d' ' -f1`
	inode=`cat $LOGPOS | cut -d' ' -f2`
fi
echo $position $inode

# get the unread part of the file
touch $TMPTAIL
chmod og-rwx $TMPTAIL
if [ -f $LOG.0 -a `ls -i $LOG | cut -d' ' -f1` -ne $inode ]; then
	# looks like logs got rotated (inode changed)
	TMPOLD=/tmp/tmplog_`hexdump -n 8 -e \"%x\" /dev/urandom`
	touch $TMPOLD
	chmod og-rwx $TMPOLD
	echo "------- log rotation : old log" >$TMPOLD
	# re-start with old file
	tail -n +$position $LOG.0 >>$TMPOLD
	# then do the old file
	position=0
	tail -n +$position $LOG >$TMPTAIL
	newposition=$(($position+`wc -l <$TMPTAIL`))
	# put them together
	echo "------- log rotation : new log" >>$TMPOLD
	cat $TMPTAIL >>$TMPOLD
	mv $TMPOLD $TMPTAIL
else
	tail -n +$position $LOG >$TMPTAIL
	newposition=$(($position+`wc -l <$TMPTAIL`))
fi

# get the rules together
touch $TMPRULES
chmod og-rwx $TMPRULES
grep -hv -e ^# $RULES/* -e ^$ >$TMPRULES

# generate message
touch $TMPMESSAGE
chmod og-rwx $TMPMESSAGE
echo "From: $SENDER" >$TMPMESSAGE
echo "To: $RECIPIENT" >>$TMPMESSAGE
echo "Subject: Logcheck Report from OpenWrt Device" >>$TMPMESSAGE
echo "Date: `date -R`" >>$TMPMESSAGE
echo >>$TMPMESSAGE
echo "Logs from $LOG filtered by $RULES/*:" >>$TMPMESSAGE
echo >>$TMPMESSAGE
linesbefore=`wc -l <$TMPMESSAGE`
if [ `wc -l <$TMPRULES` -gt 0 ]; then
	# grep stalls with empty rules file
	grep -vEf $TMPRULES $TMPTAIL >>$TMPMESSAGE
else
	# no rules so take everything
	cat $TMPTAIL >>$TMPMESSAGE
fi
newlines=$((`wc -l <$TMPMESSAGE`-$linesbefore))
# did we find something
if [ $newlines -gt 0 ]; then
	echo $?
	# send the message
	#mini_sendmail -s${SERVER} -f${SENDER} ${RECIPIENT} <$TMPMESSAGE
	msmtp $RECIPIENT < $TMPMESSAGE
fi

# tidy up
rm $TMPTAIL
rm $TMPRULES
rm $TMPMESSAGE

# write the new position and inode
echo $newposition `ls -i $LOG | cut -d' ' -f1` >$LOGPOS