#!/bin/bash
#
# CallWeaver -- An open source telephony toolkit.
#
# Copyright (C) 2010, Eris Associates Limited, UK
#
# Mike Jagdis <mjagdis@eris-associates.co.uk>
#
# See http://www.callweaver.org for more information about
# the CallWeaver project. Please do not directly contact
# any of the maintainers of this project for assistance;
# the project provides a web site, mailing lists and IRC
# channels for your use.
#
# This program is free software, distributed under the terms of
# the GNU General Public License Version 2. See the LICENSE file
# at the top of the source tree.


CW_ARGS=( "$@" )		# Grab any args passed to safe_callweaver


# This is somewhat complicated. The idea is that the hardcoded defaults
# are overridden by values in the /etc/{sysconfig,default}/callweaver,
# which are in turn overridden by anything in the environment. It is
# made more complicated by the fact that we need to know the difference
# between a variable not existing in the environment and existing but
# having a null value. Anyway...

# Save config settings found in the environment
eval `export -p | while read word keyval; do
	# In bash-mode bash reports "declare -x ..." in sh-mode "export ..."
	[[ "$word" == 'declare' ]] && keyval="${keyval#-x }"
	case $keyval in
		CALLWEAVER_*)
			echo "ENV_${keyval%%=*}=${keyval#*=}"
			;;
	esac
done`

# Set defaults
CALLWEAVER_ARGS=
CALLWEAVER_CONSOLE='yes'			# Whether or not you want a console
CALLWEAVER_COREDIR='@cwvardir@/core'		# Where core files are to be dumped
#CALLWEAVER_NOTIFY='callweaver'			# List of email addresses to notify about crashes
#CALLWEAVER_NOTIFYDEV='callweaver'		# List of email addresses to send core analyses to
#CALLWEAVER_FROM='CallWeaver'			# What to put in the "From" line of emails
#CALLWEAVER_REPLYTO='admin'			# What to put in the "Reply-to" line of emailes
CALLWEAVER_MACHINE=`hostname`			# To specify which machine has crashed when getting the mail
CALLWEAVER_SLEEPSECS=4				# Seconds to sleep before restarting
CALLWEAVER_SYSLOG='daemon'			# Syslog facility to use for logging, blank to disable syslog logging
CALLWEAVER_TERM='vt102'				# Terminal type to use for Callweaver if CALLWEAVER_TTY is not null
CALLWEAVER_TTY='9'				# TTY (if you want one) for Callweaver to run on

# Override with any local preferences
[[ -r /etc/sysconfig/callweaver ]] && . /etc/sysconfig/callweaver
[[ -r /etc/default/callweaver ]] && . /etc/default/callweaver

# Override again with environment settings
for key in ${!ENV_CALLWEAVER_*}; do
	eval "${key#ENV_}=\$$key"
done


if [[ -n "$CALLWEAVER_SYSLOG" ]]; then
	logger="$( PATH='/usr/bin:/bin:/usr/sbin:/sbin' type -p logger )"
else
	logger=
fi

logmsg()
{
	local msg="$*"
	echo "callweaver: $msg" 1>&2
	[[ -n "$logger" ]] && "$logger" -p "$CALLWEAVER_SYSLOG".info -t callweaver "$msg"
}


core_analyse()
{
	local outfile="$1"
	local bin="$2"
	local core="$3"
	shift; shift; shift
	local msg="$*"

	local gdb="$( PATH='/usr/bin:/bin:/usr/sbin:/sbin' type -p gdb )"

	if [[ -n "$gdb" ]]; then
		local tmpfile="$outfile"
		[[ "$tmpfile" == '-' ]] && tmpfile="/tmp/scw$$"

		local mimeboundary='nvhfdlaltychsifkgl'

		local sections=(
			'"bt"			"backtrace"				"Backtrace"'
			'"bt-full"		"backtrace full"			"Backtrace (full)"'
			'"threads"		"info threads"				"Threads"'
			'"threads-bt"		"thread apply all backtrace"		"Backtrace (all threads)"'
			'"threads-bt-full"	"thread apply all backtrace full"	"Backtrace (all threads, full)"'
		)

		(
			echo "set prompt"
			echo "set logging overwrite on"
			echo "set logging redirect on"

			for sect in "${sections[@]}"; do
				eval set -- $sect
				echo "set logging file $tmpfile.$1.txt"
				echo "set logging on"
				echo "$2"
				echo "set logging off"
			done

			echo "quit"
		) > "$tmpfile.cmds"

		# Gdb doesn't handle end-of-pipe at all well...
		TERM=dumb "$gdb" -q --nx "$bin" "$core" < "$tmpfile.cmds" > "$tmpfile.gdb.txt" 2>&1
		rm -f "$tmpfile.cmds"

		if [[ -n "$CALLWEAVER_NOTIFYDEV" && -x /usr/sbin/sendmail ]]; then
			local base64="$( PATH='/usr/bin:/bin:/usr/sbin:/sbin' type -p base64 )"
			local gzip="$( PATH='/usr/bin:/bin:/usr/sbin:/sbin' type -p gzip )"

			[[ -n "$base64" && -n "$gzip" ]] && "$gzip" -9 "$tmpfile".*.txt

			(
				echo "Subject: Callweaver core analysis"
				echo "From: ${CALLWEAVER_FROM:-no-reply}"
				echo "To: $CALLWEAVER_NOTIFYDEV"
				echo "Reply-to: ${CALLWEAVER_REPLYTO:-no-reply}"
				echo "MIME-Version: 1.0"
				echo "Content-type: multipart/mixed; boundary="$mimeboundary""
				echo
				echo "--$mimeboundary"
				echo "Content-Type: text/plain; charset=utf-8"
				echo "Content-Transfer-Encoding: 8bit"
				echo
				echo "$msg"
				echo

				if [[ -n "$base64" && -n "$gzip" ]]; then
					for sect in "${sections[@]}"; do
						eval set -- $sect
						echo "--$mimeboundary"
						echo "Content-Type: application/x-gzip"
						echo "Content-Description: $3"
						echo "Content-Disposition: attachment; filename=\"$1.txt.gz\""
						echo "Content-Transfer-Encoding: base64"
						echo
						"$base64" "$tmpfile.$1.txt.gz" 2> /dev/null
					done
				else
					for sect in "${sections[@]}"; do
						eval set -- $sect
						echo "--$mimeboundary"
						echo "Content-Type: text/plain; charset=utf-8"
						echo "Content-Description: $3"
						echo "Content-Disposition: attachment; filename=\"$1.txt\""
						echo
						cat "$tmpfile.$1.txt" 2> /dev/null
					done
				fi

				echo "--$mimeboundary--"
			) | /usr/sbin/sendmail -i -t
		elif [[ "$outfile" == '-' ]]; then
			for sect in "${sections[@]}"; do
				eval set -- $sect
				echo
				echo '------------------------------------------------------------------------------'
				echo "$3"
				echo '------------------------------------------------------------------------------'
				cat "$tmpfile.$1.txt"
			done 2> /dev/null
		fi

		if [[ "$outfile" == '-' ]]; then
			rm -f "$tmpfile".*
		else
			gzip -9 "$tmpfile".*.txt 2> /dev/null
		fi
	fi
}


savecore()
{
	local msg="$*"

	local coredir=
	local core

	for core in core*; do
		[[ "$core" == 'core*' ]] && break

		if [[ "$coredir" == '' ]]; then
			coredir="$( date '+%Y-%m-%d-%H:%M:%S' )"
			mkdir "$coredir"
		fi

		mv "$core" "$coredir"
		core_analyse "$coredir/$core" '@cwexecdir@/callweaver' "$coredir/$core" "$msg" &
	done

	[[ -n "$coredir" ]] && logmsg "Found and moved core dumps to $coredir"
}


run_callweaver()
{
	# We should only exit if callweaver itself exits normally, which it
	# should do when signalled by a SIGTERM or SIGINT, however SIGHUP
	# means reload configs and SIGPIPE and SIGQUIT are ignored if possible.
	trap '' HUP PIPE QUIT

	if [[ -n "$CALLWEAVER_TTY" ]]; then
		# From here on we only talk to CALLWEAVER_TTY. If the outer
		# safe_callweaver invoked setsid this becomes our controlling
		# terminal. If either setsid or session were unavailable, well,
		# sorry, this is as good as it gets.
		exec 0<> "/dev/$CALLWEAVER_TTY" 1>&0 2>&0
		stty sane

		# Whatever $TERM we have referred to something else.
		# Use $CALLWEAVER_TERM if we have it otherwise
		# assume something minimal but likely.
		export TERM="${CALLWEAVER_TERM:-vt102}"
	fi

	[[ -z "$CALLWEAVER_COREDIR" ]] || cd "$CALLWEAVER_COREDIR" || exit 1

	# Try and get the standard exit codes
	eval $(
		while read define key value comment; do
			[[ "$define" == '#define' && "$key" != '_SYSEXIST_H' ]] && echo "local $key=$value"
		done < /usr/include/sysexits.h
	)

	# If we couldn't read them for some reason this is what we actually need although
	# the values are not necessarily right...
	if [[ -z "$EX_OK" ]]; then
		local EX_OK=0
		local EX_USAGE=64
		local EX_NOUSER=67
		local EX_NOPERM=77
	fi

	if [[ "$CALLWEAVER_CONSOLE" != "no" ]]; then
		CW_ARGS[${#CW_ARGS[@]}]='-c'
	fi

	local CW_CMD=()
	if [[ -n "$CALLWEAVER_PRIORITY" ]]; then
		nice="$( PATH='/usr/bin:/bin:/usr/sbin:/sbin' type -p nice )"
		if [[ -n "$nice" ]]; then
			CW_CMD[${#CW_CMD[@]}]="$nice"
			CW_CMD[${#CW_CMD[@]}]='-n'
			CW_CMD[${#CW_CMD[@]}]="$CALLWEAVER_PRIORITY"
		else
			logmsg "nice not found - priority will NOT be adjusted"
		fi
	fi
	CW_CMD[${#CW_CMD[@]}]='@cwexecdir@/callweaver'

	# Turn job control on. This allows us to run callweaver in a new process
	# group which, in turn, allows us to go nuclear on anything it forks but
	# which does not die easily if callweaver does not exit cleanly. Notable
	# examples of such subprocesses are madplay or mpg123 which are commonly
	# used for streaming mp3s into callweaver as hold music.
	set -m

	while :; do
		# Start callweaver in the background then immediately foreground it.
		# We want callweaver in the foreground in all cases but we start
		# it in the background so that it is made a new process group leader
		# by the shell.
		"${CW_CMD[@]}" $CALLWEAVER_ARGS "${CW_ARGS[@]}" -f -g &
		local pgrp=$!
		fg > /dev/null
		local EXITSTATUS=$?

		logmsg "CallWeaver ended with exit status $EXITSTATUS"

		# Try and make sure any subprocesses spawned by callweaver get the
		# message. If they still don't we'll go nuclear on them a little
		# later...
		kill -TERM -$pgrp 2> /dev/null

		case "$EXITSTATUS" in
			$EX_OK)
				# Properly shutdown....
				logmsg "CallWeaver shutdown normally."
				exit 0
				;;

			$EX_USAGE|$EX_NOUSER|$EX_NOPERM)
				# Unrecoverable config error. Callweaver has already logged the error.
				exit $EXITSTATUS
				;;

			*)
				# Potentially recoverable...
				if [[ $EXITSTATUS -ge 128 ]]; then
					msg="CallWeaver exited on signal $(( $EXITSTATUS & 127 ))"
				else
					msg="CallWeaver died with code $EXITSTATUS"
				fi

				logmsg "$msg"

				if [[ -n "$CALLWEAVER_NOTIFY" && -x /usr/sbin/sendmail ]]; then
					/usr/sbin/sendmail -i -t <<EOF_NOTIFY
Subject: $CALLWEAVER_MACHINE: $msg
From: ${CALLWEAVER_FROM:-no-reply}
To: $CALLWEAVER_NOTIFY
Reply-to: ${CALLWEAVER_REPLYTO:-no-reply}

EOF_NOTIFY
				fi

				[[ -n "$CALLWEAVER_COREDIR" ]] && savecore "$msg"

				logmsg "Automatically restarting CallWeaver in $CALLWEAVER_SLEEPSECS seconds..."
				sleep "$CALLWEAVER_SLEEPSECS"

				EXITSTATUS=-1
				;;
		esac

		# Any processes left in the ex-callweaver's process group are
		# being Bad Citizens and ignoring instructions to stop what
		# they're doing. Clean up with extreme prejudice.
		kill -9 -$pgrp 2> /dev/null

		[[ $EXITSTATUS -ne -1 ]] && exit $EXITSTATUS
	done
}


if [[ "${0##*/}" == 'cw_coreanalyse' ]]; then
	core_analyse '-' "${CW_ARGS[@]}"
	exit
fi


if [[ -n "$SAFE_CALLWEAVER_BACKEND" ]]; then
	run_callweaver
	exit $?
fi


if [[ -n "$CALLWEAVER_COREDIR" ]]; then
	if [[ ! -d "$CALLWEAVER_COREDIR/" || ! -x "$CALLWEAVER_COREDIR/" ]]; then
		logmsg "Cannot access directory $CALLWEAVER_COREDIR/" 1>&2
		exit 1
	fi

	if [[ ! -w "$CALLWEAVER_COREDIR/" ]]; then
		logmsg "Cannot write to directory $CALLWEAVER_COREDIR/" 1>&2
		exit 1
	fi

	#
	# Let CallWeaver dump core
	#
	ulimit -c unlimited
fi

if [[ -n "$CALLWEAVER_TTY" ]]; then
	if [[ -c "/dev/tty$CALLWEAVER_TTY" && -w "/dev/tty$CALLWEAVER_TTY" ]]; then
		CALLWEAVER_TTY="tty$CALLWEAVER_TTY"
		if grep '^Linux ' /proc/version > /dev/null 2>&1; then
			CALLWEAVER_TERM='linux'
		fi
	elif [[ -c "/dev/vc/$CALLWEAVER_TTY" && -w "/dev/vc/$CALLWEAVER_TTY" ]]; then
		CALLWEAVER_TTY="vc/$CALLWEAVER_TTY"
	elif [[ ! -c "/dev/$CALLWEAVER_TTY" || ! -w "/dev/$CALLWEAVER_TTY" ]]; then
		logmsg "Cannot find your CALLWEAVER_TTY (/dev/$CALLWEAVER_TTY)" 1>&2
		exit 1
	fi
	# These might have changed so we promote them to environment overrides. That way
	# we guarantee that what the backend recieves is already adjusted as necessary
	# and usable.
	export CALLWEAVER_TTY CALLWEAVER_TERM

	setsid="$( PATH='/usr/bin:/bin:/usr/sbin:/sbin' type -p setsid )"
	if [[ -n "$setsid" ]]; then
		SAFE_CALLWEAVER_BACKEND=1 exec "$setsid" "$0" "${CW_ARGS[@]}" &
	else
		SAFE_CALLWEAVER_BACKEND=1 exec "$0" "${CW_ARGS[@]}" &
	fi
else
	run_callweaver
fi