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

CLIARGS="$*"				# Grab any args passed to safe_asterisk
TTY=""						# TTY (if you want one) for Asterisk to run on
CONSOLE=no					# Whether or not you want a console
NOTIFY=root					# 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
ASTPIDFILE=/var/run/asterisk/asterisk.pid
VARRUNOWNER="_asterisk:wheel"	# chown /var/run/asterisk if it's created.

# uncomment this line to have this script 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 "$1" >&2
	if [ "$SYSLOG" != "" ]; then
	    logger -p "${SYSLOG}.warn" -t safe_asterisk[$$] "$1"
	fi
	if [ "$LOGFILE" != "" ]; then
	    echo "safe_asterisk[$$]: $1" >> "$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 -rx 'core show version'`
if [ "`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 [ `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 2>&1 > /dev/null `
	then
		# maximum number of open files is set to the system maximum divided by two if
		# MAXFILES is not set.
		if [ "$MAXFILES" = "" ]
		then
			# just check if file-max is readable
			if [ -r /proc/sys/fs/file-max ]
			then
				MAXFILES=$(( `cat /proc/sys/fs/file-max` / 2 ))
			fi
		fi
		SYSCTL_MAXFILES="fs.file-max"
	elif `uname -s | grep Darwin 2>&1 > /dev/null `
	then
		SYSCTL_MAXFILES="kern.maxfiles"
	fi


	if [ "$SYSMAXFILES" != "" ]
	then
		if [ "$SYSCTL_MAXFILES" != "" ]
		then
			sysctl -w $SYSCTL_MAXFILES=$SYSMAXFILES
		fi
	fi

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

	varrundir=`dirname $ASTPIDFILE`
	if [ ! -d $varrundir ]; then
		mkdir -p $varrundir
		[ -n "$VARRUNOWNER" ] && chown $VARRUNOWNER $varrundir
		chmod 770 $varrundir
	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 [ "$TTY" != "" ]; then
	if [ -c /dev/tty${TTY} ]; then
		TTY=tty${TTY}
	elif [ -c /dev/vc/${TTY} ]; then
		TTY=vc/${TTY}
	else
		message "Cannot find specified TTY (${TTY})"
		exit 1
	fi
	ASTARGS="${ASTARGS} -vvvg"
	if [ "$CONSOLE" != "no" ]; then
		ASTARGS="${ASTARGS} -c"
	fi
fi
if [ ! -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 [ -d /etc/asterisk/startup.d ]; then
	for script in /etc/asterisk/startup.d/*.sh; do
		if [ -x ${script} ]; then
			. ${script}
		fi
	done
fi

run_asterisk()
{
	while :; do 

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

			PID=`cat ${ASTPIDFILE}`
			if [ -f /tmp/core.${PID} ]; then
				mv /tmp/core.${PID} ${DUMPDROP}/core.`hostname`-`date -Iseconds` &
			elif [ -f /tmp/core ]; then
				mv /tmp/core ${DUMPDROP}/core.`hostname`-`date -Iseconds` &
			fi
		else
			message "Asterisk died with code $EXITSTATUS."

			PID=`cat ${ASTPIDFILE}`
			if [ -f /tmp/core.${PID} ]; then
				mv /tmp/core.${PID} ${DUMPDROP}/core.`hostname`-`date -Iseconds` &
			elif [ -f /tmp/core ]; then
				mv /tmp/core ${DUMPDROP}/core.`hostname`-`date -Iseconds` &
			fi
		fi
		message "Automatically restarting Asterisk."
		sleep $SLEEPSECS
		if [ $KILLALLMPG123 ]
		then
			pkill -9 mpg123
		fi
	done
}

run_asterisk &
