proposed fix for run-crons.

run-crons (text/plain), 3.31 KB, created by Peter Volkov (RETIRED) on 2007-01-08 20:41:11 UTC

#!/bin/bash
#
# $Header: /var/cvsroot/gentoo-x86/sys-process/cronbase/files/run-crons-0.3.2,v 1.1 2005/03/09 12:51:34 ka0ttic Exp $
#
# 08 Jan 2007; Volkov Peter <[e-mail]> run-crons:
#     Use seconds since the epoch (date +%s) instead of time stamps to avoid
#     running crons twice caused by daylight saving time change.
#
# 08 Mar 2005; Aaron Walker <[e-mail]> run-crons:
#     Ignore the error messages from find caused by race conditions, since
#     we could care less about the error as long as the file has been removed.
#     See bug 8506.
#
# 06 May 2004; Aron Griffis <[e-mail]> run-crons:
#     Make the locking actually work.  The old code was racy.
#     Thanks to Mathias Gumz in bug 45155 for some cleanups.
#
# 23 Jun 2002; Jon Nelson <[e-mail]> run-crons:
#     fixed a race condition, where cron jobs and run-crons wanted to
#     delete touch files
#
# 20 Apr 2002; Thilo Bangert <[e-mail]> run-crons:
#     moved lastrun directory to /var/spool/cron/lastrun
#
# Author: Achim Gottinger <[e-mail]>
#
# Mostly copied from SuSE
#
# this script looks into /etc/cron.[hourly|daily|weekly|monthly]
# for scripts to be executed. The info about last run is stored in
# /var/spool/cron/lastrun

LOCKDIR=/var/spool/cron/lastrun
LOCKFILE=${LOCKDIR}/lock

mkdir -p ${LOCKDIR}

# Make sure we're not running multiple instances at once.
# Try twice to lock, otherwise give up.
for ((i = 0; i < 2; i = i + 1)); do
    ln -sn $$ ${LOCKFILE} 2>/dev/null && break

	# lock failed, check for a running process.
	# handle both old- and new-style locking.
	cronpid=$(readlink ${LOCKFILE} 2>/dev/null) ||
	cronpid=$(cat ${LOCKFILE} 2>/dev/null) ||
	continue	# lockfile disappeared? try again

	# better than kill -0 because we can verify that it's really
	# another run-crons process
	if [[ $(</proc/${cronpid}/cmdline) == $(</proc/$$/cmdline) ]] 2>/dev/null; then
		# whoa, another process is really running
		exit 0
	else
		rm -f ${LOCKFILE}
	fi
done

# Check to make sure locking was successful
if [[ ! -L ${LOCKFILE} ]]; then
	echo "Can't create or read existing ${LOCKFILE}, giving up"
	exit 1
fi

# Set a trap to remove the lockfile when we're finished
trap "rm -f ${LOCKFILE}" 0 1 2 3 15

CUR_TIME=`date +%s`

for BASE in hourly daily weekly monthly
do
    CRONDIR=/etc/cron.${BASE}

    test -d $CRONDIR || continue

    if [ -e ${LOCKDIR}/cron.$BASE ]
    then
	case $BASE in
	    hourly)
		# 1 hour -=> 60 min = 3600 sec
		TIME=$(( ${CUR_TIME} - 3600 )) ;;
	    daily)
		# 1 day -=> +1440 min = 86400 sec
		TIME=$(( ${CUR_TIME} - 86400 )) ;;
	    weekly)
		# 1 week -=> +10080 min = 604800 sec
		TIME=$(( ${CUR_TIME} - 604800 )) ;;
	    monthly)
		# 31 days -=> +44640 min = 2678400 sec
		TIME=$(( ${CUR_TIME} - 2678400 )) ;;
	esac
	[ $(<${LOCKDIR}/cron.${BASE}) -lt ${TIME} ] && rm ${LOCKDIR}/cron.${BASE}
    fi

    # if there is no touch file, make one then run the scripts
    if [ ! -e ${LOCKDIR}/cron.$BASE ]
    then
        echo ${CUR_TIME} > ${LOCKDIR}/cron.$BASE

        set +e
        for SCRIPT in $CRONDIR/*
        do
            if [[ -x $SCRIPT && ! -d $SCRIPT ]]; then
                $SCRIPT
            fi
        done
    fi
done

# Clean out bogus cron.$BASE files with future times
CUR_TIME=`date +%s`
for cronfile in ${LOCKDIR}/cron.*
do
    [ $(<${cronfile}) -gt ${CUR_TIME} ] && rm ${cronfile}
done