[solved] Segmentation fault with bash script

Question

I have a bash script that checks if it has to do something, if not it sleeps 15 secs and checks again. It works great except that after ~6hrs of just checking and sleeping it seg faults. I upped the stack limit with ulimit -s and it goes ~12hrs before it seg faults. I have a similar script that I have been using for ages that works for 24hrs no problem and I can't pinpoint where the problem is.
The check it does is to see if a file exists, if it's empty and if not, read the first line of a file and do some date comparisons. It doesn't matter if the file is empty or not the seg fault always happens.
Here's the seg fault causing script - it starts at the bottom
#!/bin/bash
# User defines
declare -i DVB_DEVICE_NUM="0"
declare CHANNELS_CONF="${HOME}/Mychannels.conf"
declare SAVE_FOLDER="${HOME}/TV/tele"
declare SCHED_FILE="$HOME/.sched-tv"
declare ZAP_COMMAND="tzap"
declare -i SLEEP=15
# Program defines
declare -i DAY="0"
declare -i START="0"
declare -i FINISH="0"
declare CHAN="0"
declare NAME="0"
declare -i MINUTES="0"
declare -i REC_START="0"
declare -i REC_HOURS="0"
declare -i REC_MINS="0"
declare -i howlong="0"
declare -i PIDOF_AZAP=0
declare -i PIDOF_CAT=0
red='\033[1;31m'
green='\033[1;32m'
yell='\033[1;33m'
cyan='\033[1;36m'
white='\033[1;37m'
reset='\033[0m'
function remove_entry {
if [ "$NAME" == "" ]; then
sed "/$DAY $START $FINISH $CHAN/d" $SCHED_FILE > /tmp/dummy
else
sed "/$DAY $START $FINISH $CHAN $NAME/d" $SCHED_FILE > /tmp/dummy
fi
mv /tmp/dummy $SCHED_FILE
function record_entry {
${ZAP_COMMAND} -a ${DVB_DEVICE_NUM} -f ${DVB_DEVICE_NUM} -d ${DVB_DEVICE_NUM} \
-c $CHANNELS_CONF -r ${CHAN} >/dev/null 2>&1 &
PIDOF_AZAP=$!
if [ "$PIDOF_AZAP" == "" ]; then
printf "$red\tError starting ${ZAP_COMMAND}.\n\tFAILED: $CHAN $START\n"
remove_entry
exit 1
fi
printf "$green\tSET CHANNEL$cyan ${CHAN}\n"
REC_MINS=$((${START}%100))
REC_HOURS=0
MINUTES=0
REC_START=$(($START-$REC_MINS))
while [ $((${REC_START}+${REC_HOURS}+${REC_MINS})) -lt $FINISH ]; do
((REC_MINS++))
((MINUTES++))
if [ ${REC_MINS} -ge 60 ]; then
REC_MINS=0
((REC_HOURS+=100))
fi
done
if [ "$NAME" == "" ]; then
declare FILE_NAME="${SAVE_FOLDER}/TV-`date +%Y%m%d-%H%M`-ch.${CHAN}-${MINUTES}.min.mpg"
else
declare FILE_NAME="${SAVE_FOLDER}/TV-${NAME}-${MINUTES}.min.mpg"
fi
dd if=/dev/dvb/adapter${DVB_DEVICE_NUM}/dvr${DVB_DEVICE_NUM} \
of=${FILE_NAME} conv=noerror &
PIDOF_CAT=$!
if (( ${PIDOF_CAT} == 0 )); then
printf "$red\tError Starting Recording.\n\t/dev/dvb/adapter${DVB_DEVICE_NUM}/dvr${DVB_DEVICE_NUM} Unavailable\n"
kill ${PIDOF_AZAP}
remove_entry
exit 1
fi
printf "$yell\tRECORDING TO :$cyan ${FILE_NAME}\n"
sleep ${MINUTES}m
kill ${PIDOF_CAT} && wait ${PIDOF_CAT} 2> /dev/null
# pkill $ZAP_COMMAND # && wait ${PIDOF_AZAP} 2> /dev/null
kill ${PIDOF_AZAP} && wait ${PIDOF_AZAP} 2> /dev/null
printf "$yell\tFINISHED REC :$cyan ${FILE_NAME}\n$reset"
remove_entry
waiting 1
function check_action {
[ -e "$SCHED_FILE" ] || waiting $SLEEP
[ "`cat $SCHED_FILE`" == "" ] && waiting $SLEEP
DAY="0"; START="0"; FINISH="0"; CHAN="0"; NAME="0"
TODAY=`date +%Y%m%d`
NOW=`date +%k%M`
while read -r DAY START FINISH CHAN NAME; do
#printf "$DAY $START $FINISH $CHAN $NAME\n"
break
done < $SCHED_FILE
if [ $DAY == $TODAY ] && [ $START -lt $NOW ]; then
printf "$red\tOld Entry : Removing $CHAN $START\n"
remove_entry
waiting 1
fi
if [ $DAY == $TODAY ] && [ $START == $NOW ]; then
record_entry
else
waiting $SLEEP
fi
function waiting {
howlong=$1
sleep $howlong && check_action
check_action
exit 0
And the script that has been working fine 24hrs at a time
#!/bin/bash
echo alarm uses a twelve hour clock
echo Type the time for the alarm to sound as 00-00-?m
echo e.g. 05-35-pm for 5:35pm :: 05-35-am for 5:35am
read TIME
function play {
A="$(date +%I-%M-%P)"
if [ $A = $TIME ]; then
for i in {1..10}; do
$(aplay -c 1 /home/$USER/alarm/chime.wav); done
exit
else
wait
fi
function wait {
sleep 15 && play
play
I was hoping to have this script idling away in screen with rtorrent, always ready to do something if need be but that's not going to happen unless I can get a clue on what part of the script I need to change to not hit any limits. My websearches are failing me on this...
Last edited by moetunes (2012-06-24 21:41:52)

Answer 1

Thanks falconindy. I changed to using a while loop.
#!/bin/bash
set -o nounset
shopt -s huponexit
# User defines
declare -i DVB_DEVICE_NUM="0"
declare CHANNELS_CONF="${HOME}/Mychannels.conf"
declare SAVE_FOLDER="${HOME}/TV/tele"
declare SCHED_FILE="$HOME/.sched-tv"
declare ZAP_COMMAND="tzap"
declare -i SLEEP=15
# Program defines
declare -i DAY="0"
declare -i START="0"
declare -i FINISH="0"
declare CHAN="0"
declare NAME="0"
declare -i MINUTES="0"
declare -i REC_START="0"
declare -i REC_HOURS="0"
declare -i REC_MINS="0"
declare -i howlong=$SLEEP
declare -i PIDOF_AZAP=0
declare -i PIDOF_CAT=0
red='\033[1;31m'
green='\033[1;32m'
yell='\033[1;33m'
cyan='\033[1;36m'
white='\033[1;37m'
reset='\033[0m'
function remove_entry {
if [ "$NAME" == "" ]; then
sed "/$DAY $START $FINISH $CHAN/d" $SCHED_FILE > /tmp/dummy
else
sed "/$DAY $START $FINISH $CHAN $NAME/d" $SCHED_FILE > /tmp/dummy
fi
mv /tmp/dummy $SCHED_FILE
function record_entry {
${ZAP_COMMAND} -a ${DVB_DEVICE_NUM} -f ${DVB_DEVICE_NUM} -d ${DVB_DEVICE_NUM} \
-c $CHANNELS_CONF -r ${CHAN} >/dev/null 2>&1 &
PIDOF_AZAP=$!
if [ "$PIDOF_AZAP" == "" ]; then
printf "$red\tError starting ${ZAP_COMMAND}.\n\tFAILED: $CHAN $START\n"
remove_entry
exit 1
fi
printf "$green\tSET CHANNEL$cyan ${CHAN}\n"
REC_MINS=$((${START}%100))
REC_HOURS=0
MINUTES=0
REC_START=$(($START-$REC_MINS))
while [ $((${REC_START}+${REC_HOURS}+${REC_MINS})) -lt $FINISH ]; do
((REC_MINS++))
((MINUTES++))
if [ ${REC_MINS} -ge 60 ]; then
REC_MINS=0
((REC_HOURS+=100))
fi
done
if [ "$NAME" == "" ]; then
declare FILE_NAME="${SAVE_FOLDER}/TV-`date +%Y%m%d-%H%M`-ch.${CHAN}-${MINUTES}.min.mpg"
else
declare FILE_NAME="${SAVE_FOLDER}/TV-${NAME}-${MINUTES}.min.mpg"
fi
dd if=/dev/dvb/adapter${DVB_DEVICE_NUM}/dvr${DVB_DEVICE_NUM} \
of=${FILE_NAME} conv=noerror &
PIDOF_CAT=$!
if (( ${PIDOF_CAT} == 0 )); then
printf "$red\tError Starting Recording.\n\t/dev/dvb/adapter${DVB_DEVICE_NUM}/dvr${DVB_DEVICE_NUM} Unavailable\n"
kill ${PIDOF_AZAP}
remove_entry
exit 1
fi
printf "$yell\tRECORDING TO :$cyan ${FILE_NAME}\n"
sleep ${MINUTES}m
kill ${PIDOF_CAT} && wait ${PIDOF_CAT} 2> /dev/null
# pkill $ZAP_COMMAND # && wait ${PIDOF_AZAP} 2> /dev/null
kill ${PIDOF_AZAP} && wait ${PIDOF_AZAP} 2> /dev/null
printf "$yell\tFINISHED REC :$cyan ${FILE_NAME}\n$reset"
remove_entry
while true; do
sleep $howlong
howlong=$SLEEP
[ -e "$SCHED_FILE" ] || continue
[ "`cat $SCHED_FILE`" == "" ] && continue
TODAY=`date +%Y%m%d`
NOW=`date +%k%M`
while read -r DAY START FINISH CHAN NAME; do
#printf "$DAY $START $FINISH $CHAN $NAME\n"
break
done < $SCHED_FILE
if [ $DAY == $TODAY ] && [ $START -lt $NOW ]; then
printf "$red\tOld Entry : Removing $CHAN $START\n"
remove_entry
howlong=1
continue
fi
if [ $DAY == $TODAY ] && [ $START == $NOW ]; then
record_entry
fi
done
exit 0
I think that should be ok now.