#!/bin/sh

# This is an example CTDB NFS callout script for Ganesha.  It is based
# on the last version of 60.ganesha shipped with CTDB.  As such, it
# does not try to monitor RPC services that were not monitored by
# 60.ganesha - this might be a useful improvement.  It has also not
# been properly tested.

# You should check your version of NFS Ganesha to see if it ships with
# a newer callout.

# To use this:
#
# * Set CTDB_NFS_CALLOUT in your CTDB configuration to point to this
#   script
#
# * Rename nfs-checks.d/{20.nfs.check,30.nlockmgr.check,50.mountd.check}
#   so that they no longer have the ".check" suffix
#
# * Install 20.nfs-ganesha.check to nfs-checks.d/20.nfs.check

# I (Martin Schwenke) hereby relicense all of my contributions to this
# callout (and, previously, to 60.ganesha) to a license compatible
# with NFS Ganesha (right now this is LGPLv3, but I'm flexible).
# There may be other contributions to be considered for relicensing,
# particularly those in commit 28cbe527d47822f870e8252495ab2a1c8fddd12f.

######################################################################

# Exit on 1st error
set -e

if [ -z "$CTDB_CLUSTER_FILESYSTEM_TYPE" ] ; then
    CTDB_CLUSTER_FILESYSTEM_TYPE="gpfs"
fi

# Override for unit testing
if [ -z "$PROCFS_PATH" ] ; then
    PROCFS_PATH="/proc"
fi

##################################################

usage ()
{
    _c=$(basename $0)
    cat <<EOF
usage: $_c { shutdown | startup }
       $_c { stop | start | check } nfs
       $_c { releaseip | takeip }
       $_c { monitor-list-shares }
EOF
    exit 1
}


##################################################
# Basic service stop and start

nfs_service="nfs-ganesha-$CTDB_CLUSTER_FILESYSTEM_TYPE"

basic_stop ()
{
    case "$1" in
	nfs)
	    service "$nfs_service" stop
	    ;;
	*)
	    usage
    esac
}

basic_start ()
{
    case "$1" in
	nfs)
	    service "$nfs_service" start
	    ;;
	*)
	    usage
    esac
}

##################################################
# "stop" and "start" options for restarting

service_stop ()
{
    case "$1" in
	nfs)
	    basic_stop "nfs"
	    ;;
	nlockmgr)
	    # Do nothing - used by statd-callout
	    :
	    ;;
	*)
	    usage
    esac
}

service_start ()
{
    case "$1" in
	nfs)
	    basic_start "nfs"
	    ;;
	nlockmgr)
	    # Do nothing - used by statd-callout
	    :
	    ;;
	*)
	    usage
    esac
}

##################################################
# Nitty gritty - monitoring and IP handling

GANRECDIR="/var/lib/nfs/ganesha"
GANRECDIR2="/var/lib/nfs/ganesha/recevents"
GANRECDIR3="/var/lib/nfs/ganesha_local"

get_cluster_fs_state ()
{
    case $CTDB_CLUSTER_FILESYSTEM_TYPE in
        gpfs)
            /usr/lpp/mmfs/bin/mmgetstate | awk 'NR == 4 { print $3 }'
            ;;
        *)
            die "File system $CTDB_CLUSTER_FILESYSTEM_TYPE not supported"
            ;;
   esac
}

create_ganesha_recdirs ()
{
    [ -n "$CTDB_GANESHA_REC_SUBDIR" ] || CTDB_GANESHA_REC_SUBDIR=".ganesha"

    _mounts=$(mount -t $CTDB_CLUSTER_FILESYSTEM_TYPE)
    if [ -z "$_mounts" ]; then
      echo "startup $CTDB_CLUSTER_FILESYSTEM_TYPE not ready"
      exit 0
    fi
    _mntpt=$(echo "$_mounts" | sort | awk 'NR == 1 {print $3}')
    _link_dst="${_mntpt}/${CTDB_GANESHA_REC_SUBDIR}"
    mkdir -vp "$_link_dst"
    if [ -e "$GANRECDIR" ]; then
        if [ ! -L "$GANRECDIR" ] ; then
            rm -vrf "$GANRECDIR"
	else
	    _t=$(readlink "$GANRECDIR")
	    if [ "$_t" != "$_link_dst" ] ; then
		rm -v "$GANRECDIR"
	    fi
        fi
    fi
    # This is not an "else".  It also re-creates the link if it was
    # removed above!
    if [ ! -e "$GANRECDIR" ]; then
        ln -sv "$_link_dst" "$GANRECDIR"
    fi

    mkdir -p "$GANRECDIR2"
    mkdir -p "$GANRECDIR3"
}

service_check ()
{
    create_ganesha_recdirs

    # Always succeed if cluster filesystem is not active
    _cluster_fs_state=$(get_cluster_fs_state)
    if [ $_cluster_fs_state != "active" ] ; then
	exit 0
    fi

    # Check that NFS Ganesha is running, according to PID file
    _pidfile="/var/run/ganesha.pid"
    _ganesha="/usr/bin/$CTDB_CLUSTER_FILESYSTEM_TYPE.ganesha.nfsd"
    if ! { read _pid < "$_pidfile" && \
	   grep "$_ganesha" "${PROCFS_PATH}/${_pid}/cmdline" ; } >/dev/null 2>&1 ; then
	echo "ERROR: NFS Ganesha not running according to PID file"
	return 1
    fi

    # Check red conditions against limit
    _reds_max=2
    _reds=$(ls $GANRECDIR3 | grep -c "red")

    if [ $_reds -ge $_reds_max ] ; then
	echo "Too many red conditions (${_reds}/${_reds_max})"
	return 1
    fi

    # Check for stall
    _stall_max=120
    _now=$(date +"%s")
    _last=$(ls -t $GANRECDIR3 | sed -n -e '1s@_.*@@p')
    [ -n $_last ] || _last=$_now  # Handle startup
    _stall=$(($_now - $_last))
    if [ $_stall -ge $_stall_max ] ; then
	echo "ERROR: Stalled for ${_stall} second(s)"
	return 1
    fi

    return 0
}

#-------------------------------------------------

get_nodenum ()
{
    _nodenum_file="${GANRECDIR}/gpfs_nodenum"

    if [ ! -f "$_nodenum_file" ]; then
	/usr/lpp/mmfs/bin/mmlsconfig myNodeConfigNumber |
	    awk '{print $2}' >"$_nodenum_file"
    fi

    cat "$_nodenum_file"
}

nfs_releaseip ()
{
    case  $CLUSTER_FILESYSTEM_TYPE in
	gpfs)
	    _nnum=$(get_nodenum)
	    _tdate=$(date +"%s")
	    _touchtgt="releaseip_${_tdate}_${_nnum}_${2}_${3}_${1}"
	    touch "${GANRECDIR2}/${_touchtgt}"
	    touch "$GANRECDIR2/my${_touchtgt}"
	    ;;
    esac
}

nfs_takeip ()
{
    case  $CLUSTER_FILESYSTEM_TYPE in
	gpfs)
	    _nnum=$(get_nodenum)
	    _tdate=$(date +"%s")
	    _touchtgt="takeip_${_tdate}_${_nnum}_${2}_${3}_${1}"
	    touch "${GANRECDIR2}/${_touchtgt}"
	    ;;
    esac
}

##################################################
# service init startup and final shutdown

nfs_shutdown ()
{
    basic_stop "nfs"
}

nfs_startup ()
{
    create_ganesha_recdirs

    basic_stop "nfs" || true
    basic_start "nfs"
    _f="${PROCFS_PATH}/sys/net/ipv4/tcp_tw_recycle"
    if [ "$_f" ] ; then
	echo 1 >"$_f"
    fi
}

##################################################
# list share directories

nfs_monitor_list_shares ()
{
    grep Path /etc/ganesha/$CTDB_CLUSTER_FILESYSTEM_TYPE.ganesha.exports.conf |
	cut -f2 -d\" |
	sort -u
}

##################################################

action="$1"
shift

case "$action" in
    shutdown)            nfs_shutdown            ;;
    startup)             nfs_startup             ;;
    stop)                service_stop "$1"       ;;
    start)               service_start "$1"      ;;
    check)               service_check "$1"      ;;
    releaseip)           nfs_releaseip "$@"      ;;
    takeip)              nfs_takeip "$@"         ;;
    monitor-list-shares) nfs_monitor_list_shares ;;
    register|monitor-pre|monitor-post)
	# Not required/implemented
	:
	;;
    *)
	usage
esac