Created
January 26, 2014 15:18
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crontab script for Synology Diskstation
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#!/bin/sh | |
# | |
# Provides missing crontab editing | |
# Note: Synology crond requires arguments separated by a TAB character | |
# and the crontab user field only supports root. These requirements are | |
# enforced by this script. | |
# | |
# John Kelly, 2013-05-03 | |
# | |
SCRIPTNAME=`basename $0` | |
# Failed edits are kept in this file | |
CHKCRON=/etc/crontab.chk | |
# Previous version | |
TMPNAME=/etc/crontab.old | |
# Max versions to keep. One or greater | |
MAXVER=3 | |
# Set to your editor of choice | |
EDITOR=nano | |
usage () { | |
echo -e "Usage: $SCRIPTNAME [-l | -f | -e | -h]\n" | |
} | |
# Basic sanity checks. Running as root. One Parameter only. | |
[[ "`id -u`" = "0" ]] || ( echo "Root only"; exit 1 ) | |
[[ $# -ne 1 ]] && ( usage; exit 1 ) | |
# Check for selected editor. Default to vi | |
EDITOR=`/usr/bin/which $EDITOR` | |
[[ ! -x "$EDITOR" ]] && EDITOR=/bin/vi | |
show_help () { | |
echo -e "Provides basic access to the crontab file" | |
echo -e "with simple format checks.\n" | |
usage | |
echo " -l : Lists the current contents of the root crontab file." | |
echo " -f : Refreshes the cron daemon." | |
echo " -e : Edits the crontab file and refreshes the cron daemon if" | |
echo " the file is actually changed. Otherwise does nothing." | |
echo -e " -h : Shows this help text.\n" | |
exit 0 | |
} | |
check_new () { | |
# Synocron is very picky. Check the file format | |
( # Start of output redirection block | |
IFS=" | |
" | |
cat /etc/crontab | \ | |
while read LINE; do | |
# Find out if empty or the first character is a # | |
echo "${LINE}" | awk '{print $1}' | egrep "^#|^$" >/dev/null 2>&1 | |
if [[ $? = 0 ]]; then | |
# Copy over comment/blank lines exactly | |
echo "$LINE" | |
else | |
unset IFS | |
# test convert using tabs to compare results | |
echo "$LINE" | while read MIN HO MD MO WD WH COM; do | |
echo -e "$MIN\t$HO\t$MD\t$MO\t$WD\troot\t$COM" | |
done | |
IFS=" | |
" | |
fi | |
done | |
) > $CHKCRON # end of output redirection block | |
# Compare files and return the result | |
diff /etc/crontab $CHKCRON >/dev/null 2>&1 | |
return $? | |
} | |
restart_cron () { | |
echo "Refreshing cron daemon." | |
/usr/syno/sbin/synoservice --restart crond | |
} | |
archive () { # Keep up to MAXVER versions | |
ARCVER=$MAXVER | |
while [[ $ARCVER -gt 1 ]]; do | |
PRVVER=`expr $ARCVER - 1` | |
mv -f $TMPNAME.$PRVVER $TMPNAME.$ARCVER | |
ARCVER=$PRVVER | |
done | |
cp $TMPNAME ${TMPNAME}.1 | |
} | |
edit_cron () { | |
archive | |
cp /etc/crontab ${TMPNAME} | |
$EDITOR /etc/crontab | |
diff /etc/crontab ${TMPNAME} >/dev/null 2>&1 | |
if [[ $? = 0 ]]; then | |
echo "No changes made. Doing nothing." | |
else | |
if check_new; then | |
echo "Crontab altered." | |
echo "Previous version saved in ${TMPNAME}" | |
rm -f $CHKCRON | |
restart_cron | |
else | |
echo "Crontab file is NOT in the correct Synology format." | |
echo "Please use TABs between fields and specify root in sixth field." | |
echo "Your version is saved in $CHKCRON. Restoring original version." | |
cat /etc/crontab > $CHKCRON | |
cat $TMPNAME > /etc/crontab | |
fi | |
fi | |
exit 0 | |
} | |
### Script flow ################### | |
while getopts lfhe flag; do | |
case $flag in | |
l) cat /etc/crontab; exit 0;; | |
e) edit_cron;; | |
f) restart_cron;; | |
h) show_help;; | |
?) usage;; | |
esac | |
done | |
## End of script flow ############# |
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