#!/bin/sh
# vim:textwidth=80:tabstop=4:shiftwidth=4:smartindent:autoindent

CLIARGS="$*"				# Grab any args passed to safe_asterisk
TTY=9						# TTY (if you want one) for Asterisk to run on
CONSOLE=yes					# Whether or not you want a console
#NOTIFY=ben@alkaloid.net	# Who to notify about crashes
#EXEC=/path/to/somescript	# Run this command if Asterisk crashes
#LOGFILE=/path/to/logfile	# Where to place the normal logfile (disabled if blank)
#SYSLOG=local0				# Which syslog facility to use (disabled if blank)
MACHINE=`hostname`			# To specify which machine has crashed when getting the mail
DUMPDROP=/tmp
SLEEPSECS=4
ASTSBINDIR=/usr/local/sbin
ASTVARRUNDIR=/var/run/asterisk
ASTPIDFILE=${ASTVARRUNDIR}/asterisk.pid

# comment this line out to have this script _not_ kill all mpg123 processes when
# asterisk exits
KILLALLMPG123=1

# run asterisk with this priority
PRIORITY=0

# set system filemax on supported OSes if this variable is set
# SYSMAXFILES=262144

# Asterisk allows full permissions by default, so set a umask, if you want
# restricted permissions.
#UMASK=022

# set max files open with ulimit. On linux systems, this will be automatically
# set to the system's maximum files open devided by two, if not set here.
# MAXFILES=32768

message() {
	echo "$1" >&2
	if test "x$SYSLOG" != "x" ; then
	    logger -p "${SYSLOG}.warn" -t safe_asterisk[$$] "$1"
	fi
	if test "x$LOGFILE" != "x" ; then
	    echo "safe_asterisk[$$]: $1" >> "$LOGFILE"
	fi
}

# Check if Asterisk is already running.  If it is, then bug out, because
# starting safe_asterisk when Asterisk is running is very bad.
VERSION=`${ASTSBINDIR}/asterisk -nrx 'core show version'`
if test "`echo $VERSION | cut -c 1-8`" = "Asterisk" ; then
	message "Asterisk is already running.  $0 will exit now."
	exit 1
fi

# since we're going to change priority and open files limits, we need to be
# root. if running asterisk as other users, pass that to asterisk on the command
# line.
# if we're not root, fall back to standard everything.
if test `id -u` != 0 ; then
	echo "Oops. I'm not root. Falling back to standard prio and file max." >&2
	echo "This is NOT suitable for large systems." >&2
	PRIORITY=0
	message "safe_asterisk was started by `id -n` (uid `id -u`)."
else
	if `uname -s | grep Linux >/dev/null 2>&1`; then
		# maximum number of open files is set to the system maximum divided by two if
		# MAXFILES is not set.
		if test "x$MAXFILES" = "x" ; then
			# just check if file-max is readable
			if test -r /proc/sys/fs/file-max ; then
				MAXFILES=$(( `cat /proc/sys/fs/file-max` / 2 ))
			fi
		fi
		SYSCTL_MAXFILES="fs.file-max"
	elif `uname -s | grep Darwin /dev/null 2>&1`; then
		SYSCTL_MAXFILES="kern.maxfiles"
	fi


	if test "x$SYSMAXFILES" != "x"; then
		if test "x$SYSCTL_MAXFILES" != "x"; then
			sysctl -w $SYSCTL_MAXFILES=$SYSMAXFILES
		fi
	fi

	# set the process's filemax to whatever set above
	ulimit -n $MAXFILES

	if test ! -d ${ASTVARRUNDIR} ; then
		mkdir -p ${ASTVARRUNDIR}
		chmod 770 ${ASTVARRUNDIR}
	fi

fi

if test "x$UMASK" != "x"; then
	umask $UMASK
fi

#
# Let Asterisk dump core
#
ulimit -c unlimited

#
# Don't fork when running "safely"
#
ASTARGS=""
if test "x$TTY" != "x" ; then
	if test -c /dev/tty${TTY} ; then
		TTY=tty${TTY}
	elif test -c /dev/vc/${TTY} ; then
		TTY=vc/${TTY}
	else
		message "Cannot find specified TTY (${TTY})"
		exit 1
	fi
	ASTARGS="${ASTARGS} -vvvg"
	if test "x$CONSOLE" != "xno" ; then
		ASTARGS="${ASTARGS} -c"
	fi
fi
if test ! -w "${DUMPDROP}" ; then	
	message "Cannot write to ${DUMPDROP}"
	exit 1
fi

#
# Don't die if stdout/stderr can't be written to
#
trap '' PIPE

#
# Run scripts to set any environment variables or do any other system-specific setup needed
#

if test -d /etc/asterisk/startup.d ; then
	for script in /etc/asterisk/startup.d/*.sh; do
		if test -r ${script} ; then
			. ${script}
		fi
	done
fi

run_asterisk()
{
	while :; do 

		if test "x$TTY" != "x" ; then
			cd /tmp
			stty sane < /dev/${TTY}
			nice -n $PRIORITY ${ASTSBINDIR}/asterisk -f ${CLIARGS} ${ASTARGS} > /dev/${TTY} 2>&1 < /dev/${TTY}
		else
			cd /tmp
			nice -n $PRIORITY ${ASTSBINDIR}/asterisk -f ${CLIARGS} ${ASTARGS}
		fi
		EXITSTATUS=$?
		message "Asterisk ended with exit status $EXITSTATUS"
		if test "x$EXITSTATUS" = "x0" ; then
			# Properly shutdown....
			message "Asterisk shutdown normally."
			exit 0
		elif test "0$EXITSTATUS" -gt "128" ; then
			EXITSIGNAL=$(($EXITSTATUS - 128))
			echo "Asterisk exited on signal $EXITSIGNAL."
			if test "x$NOTIFY" != "x" ; then
				echo "Asterisk on $MACHINE exited on signal $EXITSIGNAL.  Might want to take a peek." | \
				mail -s "Asterisk Died" $NOTIFY
				message "Exited on signal $EXITSIGNAL"
			fi
			if test "x$EXEC" != "x" ; then
				$EXEC
			fi

			PID=`cat ${ASTPIDFILE}`
			DATE=`date "+%Y-%m-%dT%H:%M:%S%z"`
			if test -f /tmp/core.${PID} ; then
				mv /tmp/core.${PID} ${DUMPDROP}/core.`hostname`-$DATE &
			elif test -f /tmp/core ; then
				mv /tmp/core ${DUMPDROP}/core.`hostname`-$DATE &
			fi
		else
			message "Asterisk died with code $EXITSTATUS."

			PID=`cat ${ASTPIDFILE}`
			DATE=`date "+%Y-%m-%dT%H:%M:%S%z"`
			if test -f /tmp/core.${PID} ; then
				mv /tmp/core.${PID} ${DUMPDROP}/core.`hostname`-$DATE &
			elif test -f /tmp/core ; then
				mv /tmp/core ${DUMPDROP}/core.`hostname`-$DATE &
			fi
		fi
		message "Automatically restarting Asterisk."
		sleep $SLEEPSECS
		if test "0$KILLALLMPG123" -gt "0" ; then
			pkill -9 mpg123
		fi
	done
}

run_asterisk &
