Upstart and Digi Etherlite 32

Here's how to get your Etherlite working with upstart. But really, this technique would apply to any serial connection.

First we need /etc/init/dgrp.conf.

# Digi EtherLite
# Starts a agetty for each serial port
# Normally run from the start-dgrp.conf task

stop on runlevel [S016]

env TERM=vt100
env BAUD=19200
respawn
instance $ID
exec /sbin/agetty -L tty$ID ${BAUD:-19200} ${TERM:-vt100}

usage 'dgrp ID=XX [BAUD=YYYYY] [TERM=ZZZZ]  - where XX is terminal id (A10) and YYYYY is baud (12900) and ZZZZ is the termcap entry (vt100)'

You can test this by starting an agetty on ttyA01 with:

initctl start dgrp ID=A01

Stop it with:

initctl stop dgrp ID=A01

Now create /etc/sysconfig/dgrp. Each line is the ID with an optional baud rate (default 19200) and TERM (default vt100) setting:

A01
A02 9600 vt100
A10 19200 wy60

Now we create the controlling task. This gets run after rc?.d is finished. It reads /etc/sysconfig/dgrp and runs dgrp.conf where needed.

# Digi Etherlite
# This task will read /etc/sysconfig/dgrp and will run dgrp.conf for each line in it
# It is run after all rc?.d the scripts are run

start on stopped rc RUNLEVEL=[2345]

env CONFIG=/etc/sysconfig/dgrp
task
script
    test -f $CONFIG || ( logger -t start-dgrp.conf "$CONFIG doesn't exist"; exit 0 )
    test -d /proc && test -d /proc/dgrp || ( logger -t start-dgrp.conf "drpd daemon is not running" ; exit 3 )

    temp=$(mktemp --tmpdir)
    grep -v '#' $CONFIG >$temp

    while read ID BAUD TERM ; do
        ID=$(basename $ID)
        initctl start dgrp ID=${ID/tty} BAUD=$BAUD TERM=$TERM
    done < $temp
end script

We use a temporary file so that we can ignore comments in the dgrp config file.