#!/bin/sh
#
# mkconf -- outputs valid mdadm.conf contents for the local system
#
# Copyright © martin f. krafft <madduck@madduck.net>
# distributed under the terms of the Artistic Licence 2.0
#
# $Id: mkconf 261 2006-11-09 13:32:35Z madduck $
#

set -eu

ME="${0##*/}"
MDADM=/sbin/mdadm
DEBIANCONFIG=/etc/default/mdadm
CONFIG=/etc/mdadm.conf

test -r $DEBIANCONFIG && . $DEBIANCONFIG

if [ -n "${MDADM_MAILADDR__:-}" ]
then
    # honour MAILADDR from the environment (from postinst)
    MAILADDR="$MDADM_MAILADDR__"
else
    # preserve existing MAILADDR
    MAILADDR="$(sed -ne 's,MAILADDR ,,p' $CONFIG 2>/dev/null || echo root)"
fi

generate=0
[ "${1:-}" = force-generate ] && rm -f $CONFIG
case "${1:-}" in
    generate|force-generate)
        [ -n "${2:-}" ] && CONFIG=$2
        # only barf if the config file specifies anything else than MAILADDR
        if egrep -qv '^(MAILADDR.*|#.*|)$' $CONFIG 2>/dev/null
        then
            echo "E: $ME: $CONFIG already exists." >&2
            exit 255
        fi
        mkdir --parent ${CONFIG%/*}
        exec >$CONFIG
        generate=1
        ;;
esac

cat <<_eof
# mdadm.conf
#
# Please refer to mdadm.conf(5) for information about this file.
#
# MD monitor
START_MDADMMONITOR=False

# by default, scan all partitions (/proc/partitions) for MD superblocks.
# alternatively, specify devices to scan, using wildcards if desired.
DEVICE partitions

# auto-create devices with Debian standard permissions
CREATE owner=root group=disk mode=0660 auto=yes

# automatically tag new arrays as belonging to the local system
HOMEHOST <system>

# instruct the monitoring daemon where to send mail alerts
MAILADDR $MAILADDR

_eof

error=0
if [ ! -r /proc/mdstat ]
then
    echo W: $ME: MD subsystem is not loaded, thus I cannot scan for arrays. >&2
    error=1
elif [ ! -r /proc/partitions ]
then
    echo W: $ME: /proc/partitions cannot be read, thus I cannot scan for arrays. >&2
    error=2
else
    echo "# definitions of existing MD arrays"
    if ! $MDADM --examine --scan --config=partitions
    then
        error=$(($? + 128))
        echo W: $ME: failed to scan for partitions. >&2
        echo "### WARNING: scan failed."
    else
        echo
    fi
fi

if [ $generate -eq 1 ]
then
    cat <<_eof
# This file was auto-generated on $(date -R)
# by mkconf \$Id: mkconf 261 2006-11-09 13:32:35Z madduck $
_eof
    mkdir -p /var/lib/mdadm
    md5sum $CONFIG > /var/lib/mdadm/mdadm.conf-generated
fi

exit $error