#!/bin/ksh

ETCMAIL="/etc/mail"
CFDIR="/usr/lib/mail"
M4=${M4:-/usr/bin/m4}

Usage() {
	
	cat<<EOF
  Create a new sendmail configuration file using a m4 mail config file.

  Usage: $0 [-h] [-s] [-c file] [-d dir]

    h       .. print this help and exit (highest priority)
    c file  .. create a new ${ETCMAIL}/sendmail.cf using file to get 
               mail configuration settings (medium priority)
    s       .. create a new ${ETCMAIL}/sendmail.cf using the file
               ${ETCMAIL}/server.mc. This is meant as an example, only.
               You should copy the server.mc to another file 
               (e.g. myserver.mc), adjust the settings and call 
               $0 -c myserver.mc .
    d dir   .. create the sendmail configuration file as well as the
               sendmail.cf link to this file in the directory dir
    
    Without any option, $0 creates a new ${ETCMAIL}/sendmail.cf from
    the file ${ETCMAIL}/client.mc. This is a nullclient configuration file,
    which instructs sendmail to send all mails unmangled to the central
    mail gateway named "mailhost".

EOF

}

if [ ! -d "$ETCMAIL" ]; then
	echo "Mail configuration directory $ETCMAIL does not exist!"
	exit 1
fi
if [ ! -d "$CFDIR" ]; then
	echo "Sendmail m4 configuration files directory $CFDIR does not exist!"
	exit 2
fi

if [ ! -x "$M4" ]; then
	M4=`which m4 2>/dev/null`
	if [ -n "$M4" -a -x "$M4" ]; then
		echo "Using $M4 as macro processor."
	elif [ -x /local/usr/bin/m4 ]; then
		M4=/local/usr/bin/m4
	elif [ -x /usr/local/bin/m4 ]; then
		M4=/usr/local/bin/m4
	else
		echo "Unable to find a usable m4 macro processor!"
		exit 3
	fi
fi
DESTDIR=$ETCMAIL

while getopts :"hsc:d:" ARG; do
	case $ARG in
		s)
			SERVER="true"
			;;
		c)
			CFFILE=$OPTARG
			;;
		d)
			if [ -d $OPTARG ]; then
				DESTDIR=$OPTARG
			else
				echo "Directory $OPTARG does not exists."
				exit 7
			fi
			;;
		h|*)
			Usage
			exit 1
			;;
	esac
done
		

if [ -z "$CFFILE" ]; then
	if [ -n "$SERVER" ]; then
		CFFILE="${ETCMAIL}/server.mc"
	else
		CFFILE="${ETCMAIL}/client.mc"
	fi
else
	F=${CFFILE##/}
	if [ "$F" == "$CFFILE" ]; then
		CFFILE=`pwd`/$CFFILE
	fi
fi

if [ ! -r "$CFFILE" ]; then
	echo "sendmail m4 configuration file $CFFILE is not readable."
	exit 4
else
	echo "Using $CFFILE for configuration."
fi

TARGET=${CFFILE##*/}
TARGET=${TARGET%.*}'.cf'

if [ "${DESTDIR}/$TARGET" == "$CFFILE" ]; then
	cat<<EOF

  Please rename your configuration file to something else than
  ${CFFILE} since we do not want to overwrite it.
  E.g.: ${DESTDIR}/${TARGET}.mc

EOF
	exit 5
fi

$M4 -D_CF_DIR_=${CFDIR}/ ${CFDIR}/m4/cf.m4 ${CFFILE} >${DESTDIR}/${TARGET}.tmp

if [ $? -ne 0 ]; then
	echo "Unable to produce ${DESTDIR}/${TARGET}."
	echo "${DESTDIR}/${TARGET}.tmp contains, what I got so far."
	echo "Delete it, if you do not need it for troubleshooting."
	exit 6
fi

cd $DESTDIR
if [ -e "$TARGET" ]; then
	mv ${TARGET} ${TARGET}.bak
fi
mv ${TARGET}.tmp ${TARGET}
chmod 644 ${TARGET}
rm -f sendmail.cf
ln -sf ./${TARGET} sendmail.cf

cat<<EOF

 Done.
 Check the new ${DESTDIR}/sendmail.cf and restart sendmail, if it is ok.
EOF

if [ -e ${TARGET}.bak ]; then
	cat<<EOF
 Otherwise cp the old ${DESTDIR}/${TARGET}.bak back to ${DESTDIR}/sendmail.cf .

EOF

fi