samba-mirror/ctdb/config/functions

# Hey Emacs, this is a -*- shell-script -*- !!!

# utility functions for ctdb event scripts

PATH=/bin:/usr/bin:/usr/sbin:/sbin:$PATH

[ -z "$CTDB_VARDIR" ] && {
    if [ -d "/var/lib/ctdb" ] ; then
	export CTDB_VARDIR="/var/lib/ctdb"
    else
	export CTDB_VARDIR="/var/ctdb"
    fi
}
[ -z "$CTDB_ETCDIR" ] && {
    export CTDB_ETCDIR="/etc"
}

#######################################
# pull in a system config file, if any
_loadconfig() {

    if [ -z "$1" ] ; then
	foo="${service_config:-${service_name}}"
	if [ -n "$foo" ] ; then
	    loadconfig "$foo"
	fi
    elif [ "$1" != "ctdb" ] ; then
	loadconfig "ctdb"
    fi

    if [ -f $CTDB_ETCDIR/sysconfig/$1 ]; then
	. $CTDB_ETCDIR/sysconfig/$1
    elif [ -f $CTDB_ETCDIR/default/$1 ]; then
	. $CTDB_ETCDIR/default/$1
    elif [ -f $CTDB_BASE/sysconfig/$1 ]; then
	. $CTDB_BASE/sysconfig/$1
    fi
}

loadconfig () {
    _loadconfig "$@"
}

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

# CTDB_SCRIPT_DEBUGLEVEL can be overwritten by setting it in a
# configuration file.
debug ()
{
    if [ ${CTDB_SCRIPT_DEBUGLEVEL:-2} -ge 4 ] ; then
	# If there are arguments then echo them.  Otherwise expect to
	# use stdin, which allows us to pass lots of debug using a
	# here document.
	if [ -n "$1" ] ; then
	    echo "DEBUG: $*"
	elif ! tty -s ; then
	    sed -e 's@^@DEBUG: @'
	fi
    fi
}

die ()
{
    _msg="$1"
    _rc="${2:-1}"

    echo "$_msg"
    exit $_rc
}

# Log given message or stdin to either syslog or a CTDB log file
# $1 is the tag passed to logger if syslog is in use.
script_log ()
{
    _tag="$1" ; shift

    _using_syslog=false
    if [ "$CTDB_SYSLOG" = "yes" -o -z "$CTDB_LOGFILE" ] ; then
	_using_syslog=true
    fi
    case "$CTDB_OPTIONS" in
	*--syslog*) _using_syslog=true ;;
    esac

    if $_using_syslog ; then
	logger -t "ctdbd: ${_tag}" $*
    else
	{
	    if [ -n "$*" ] ; then
		echo "$*"
	    else
		cat
	    fi
	} >>"${CTDB_LOGFILE:-/var/log/log.ctdb}"
    fi
}

# When things are run in the background in an eventscript then logging
# output might get lost.  This is the "solution".  :-)
background_with_logging ()
{
    (
	"$@" 2>&1 </dev/null |
	script_log "${script_name}&"
    )&

    return 0
}

##############################################################
# check number of args for different events
ctdb_check_args ()
{
    case "$1" in
	takeip|releaseip)
	    if [ $# != 4 ]; then
		echo "ERROR: must supply interface, IP and maskbits"
		exit 1
	    fi
	    ;;
	updateip)
	    if [ $# != 5 ]; then
		echo "ERROR: must supply old interface, new interface, IP and maskbits"
		exit 1
	    fi
	    ;;
    esac
}

##############################################################
# determine on what type of system (init style) we are running
detect_init_style() {
    # only do detection if not already set:
    test "x$CTDB_INIT_STYLE" != "x" && return

    if [ -x /sbin/startproc ]; then
        CTDB_INIT_STYLE="suse"
    elif [ -x /sbin/start-stop-daemon ]; then
        CTDB_INIT_STYLE="debian"
    else
        CTDB_INIT_STYLE="redhat"
    fi
}

######################################################
# simulate /sbin/service on platforms that don't have it
# _service() makes it easier to hook the service() function for
# testing.
_service ()
{
  _service_name="$1"
  _op="$2"

  # do nothing, when no service was specified
  [ -z "$_service_name" ] && return

  if [ -x /sbin/service ]; then
      $_nice /sbin/service "$_service_name" "$_op"
  elif [ -x $CTDB_ETCDIR/init.d/$_service_name ]; then
      $_nice $CTDB_ETCDIR/init.d/$_service_name "$_op"
  elif [ -x $CTDB_ETCDIR/rc.d/init.d/$_service_name ]; then
      $_nice $CTDB_ETCDIR/rc.d/init.d/$_service_name "$_op"
  fi
}

service()
{
    _nice=""
    _service "$@"
}

######################################################
# simulate /sbin/service (niced) on platforms that don't have it
nice_service()
{
    _nice="nice"
    _service "$@"
}

######################################################
# wrapper around /proc/ settings to allow them to be hooked
# for testing
# 1st arg is relative path under /proc/, 2nd arg is value to set
set_proc ()
{
    echo "$2" >"/proc/$1"
}

######################################################
# wrapper around getting file contents from /proc/ to allow
# this to be hooked for testing
# 1st arg is relative path under /proc/
get_proc ()
{
    cat "/proc/$1"
}

######################################################
# Check that an RPC service is healthy -
# this includes allowing a certain number of failures
# before marking the NFS service unhealthy.
#
# usage: nfs_check_rpc_service SERVICE_NAME [ triple ...]
#
# each triple is a set of 3 arguments: an operator, a 
# fail count limit and an action string.
#
# For example:
#
# 	nfs_check_rpc_service "lockd" \
#	    -ge 15 "verbose restart unhealthy" \
#	    -eq 10 "restart:bs"
#
# says that if lockd is down for 15 iterations then do
# a verbose restart of lockd and mark the node unhealthy.
# Before this, after 10 iterations of failure, the
# service is restarted silently in the background.
# Order is important: the number of failures need to be
# specified in reverse order because processing stops
# after the first condition that is true.
######################################################
nfs_check_rpc_service ()
{
    _prog_name="$1" ; shift

    _v=""
    case "$1" in
	-*) : ;;
	*) _v="$1" ; shift ;;
    esac

    _version=${_v:-1}
    _rpc_prog="$_prog_name"
    _restart=""
    _opts=""
    case "$_prog_name" in
	knfsd)
	    _rpc_prog=nfs
	    _version=${_v:-3}
	    _restart="echo 'Trying to restart NFS service'"
	    _restart="${_restart}; startstop_nfs restart"
	    ;;
	ganesha)
	    _rpc_prog=nfs
	    _version=${_v:-3}
	    _restart="echo 'Trying to restart Ganesha NFS service'"
	    _restart="${_restart}; startstop_ganesha restart"
	    ;;
	mountd)
	    _opts="${MOUNTD_PORT:+ -p }${MOUNTD_PORT}"
	    ;;
	rquotad)
	    _opts="${RQUOTAD_PORT:+ -p }${RQUOTAD_PORT}"
	    ;;
	lockd)
	    _rpc_prog=nlockmgr
	    _version=${_v:-4}
	    _restart="echo 'Trying to restart lock manager service'"
	    _restart="${_restart}; startstop_nfslock restart"
	    ;;
	statd)
	    _rpc_prog=status
	    _opts="${STATD_HOSTNAME:+ -n }${STATD_HOSTNAME}"
	    _opts="${_opts}${STATD_PORT:+ -p }${STATD_PORT}"
	    _opts="${_opts}${STATD_OUTGOING_PORT:+ -o }${STATD_OUTGOING_PORT}"
	    ;;
	*)
	    echo "Internal error: unknown RPC program \"$_prog_name\"."
	    exit 1
    esac

    _service_name="nfs_${_prog_name}"

    if ctdb_check_rpc "$_rpc_prog" $_version >/dev/null ; then
	ctdb_counter_init "$_service_name"
	return 0
    fi

    ctdb_counter_incr "$_service_name"

    while [ -n "$3" ] ; do
	ctdb_check_counter "quiet" "$1" "$2" "$_service_name" || {
	    for _action in $3 ; do
		case "$_action" in
		    verbose)
			echo "$ctdb_check_rpc_out"
			;;
		    restart|restart:*)
			# No explicit command specified, construct rpc command.
			if [ -z "$_restart" ] ; then
			    _p="rpc.${_prog_name}"
			    _restart="echo 'Trying to restart $_prog_name [${_p}${_opts}]'"
			    _restart="${_restart}; killall -q -9 $_p"
			    _restart="${_restart}; $_p $_opts"
			fi

			# Process restart flags...
			_flags="${_action#restart:}"
			# There may not have been a colon...
			[ "$_flags" != "$_action" ] || _flags=""
			# q=quiet - everything to /dev/null
			if [ "${_flags#*q}" != "$_flags" ] ; then
			    _restart="{ ${_restart} ; } >/dev/null 2>&1"
			fi
			# s=stealthy - last command to /dev/null
			if [ "${_flags#*s}" != "$_flags" ] ; then
			    _restart="${_restart} >/dev/null 2>&1"
			fi
			# b=background - the whole thing, easy and reliable
			if [ "${_flags#*b}" != "$_flags" ] ; then
			    _restart="{ ${_restart} ; } &"
			fi

			# Do it!
			eval "${_restart}"
			;;
		    unhealthy)
			exit 1
			;;
		    *)
			echo "Internal error: unknown action \"$_action\"."
			exit 1
		esac
	    done

	    # Only process the first action group.
	    break
	}
	shift 3
    done
}

######################################################
# check that a rpc server is registered with portmap
# and responding to requests
# usage: ctdb_check_rpc SERVICE_NAME VERSION
######################################################
ctdb_check_rpc ()
{
    progname="$1"
    version="$2"

    if ! ctdb_check_rpc_out=$(rpcinfo -u localhost $progname $version 2>&1) ; then
	ctdb_check_rpc_out="ERROR: $progname failed RPC check:
$ctdb_check_rpc_out"
	echo "$ctdb_check_rpc_out"
	return 1
    fi
}

######################################################
# check a set of directories is available
# return 1 on a missing directory
# usage: ctdb_check_directories_probe SERVICE_NAME <directories...>
######################################################
ctdb_check_directories_probe() {
    while IFS="" read d ; do
	case "$d" in
	    *%*)
		continue
		;;
	    *)
		[ -d "${d}/." ] || return 1
	esac
    done
}

######################################################
# check a set of directories is available
# usage: ctdb_check_directories SERVICE_NAME <directories...>
######################################################
ctdb_check_directories() {
    n="${1:-${service_name}}"
    ctdb_check_directories_probe || {
	echo "ERROR: $n directory \"$d\" not available"
	exit 1
    }
}

######################################################
# check a set of tcp ports
# usage: ctdb_check_tcp_ports <ports...>
######################################################

# This flag file is created when a service is initially started.  It
# is deleted the first time TCP port checks for that service succeed.
# Until then ctdb_check_tcp_ports() prints a more subtle "error"
# message if a port check fails.
_ctdb_check_tcp_common ()
{
    _ctdb_service_started_file="$ctdb_fail_dir/$service_name.started"
}

ctdb_check_tcp_init ()
{
    _ctdb_check_tcp_common
    mkdir -p "${_ctdb_service_started_file%/*}" # dirname
    touch "$_ctdb_service_started_file"
}

ctdb_check_tcp_ports()
{
    if [ -z "$1" ] ; then
	echo "INTERNAL ERROR: ctdb_check_tcp_ports - no ports specified"
	exit 1
    fi

    # Set default value for CTDB_TCP_PORT_CHECKS if unset.
    # If any of these defaults are unsupported then this variable can
    # be overridden in /etc/sysconfig/ctdb or via a file in
    # /etc/ctdb/rc.local.d/.
    : ${CTDB_TCP_PORT_CHECKERS:=ctdb nmap netstat}

    for _c in $CTDB_TCP_PORT_CHECKERS ; do
	ctdb_check_tcp_ports_$_c "$@"
	case "$?" in
	    0)
		_ctdb_check_tcp_common
		rm -f "$_ctdb_service_started_file"
		return 0
		;;
	    1)
		_ctdb_check_tcp_common
		if [ ! -f "$_ctdb_service_started_file" ] ; then
		    echo "ERROR: $service_name tcp port $_p is not responding"
		    debug <<EOF
$ctdb_check_tcp_ports_debug
EOF
		else
		    echo "INFO: $service_name tcp port $_p is not responding"
		fi

		return 1
		;;
	    127)
		debug <<EOF
ctdb_check_ports - checker $_c not implemented
output from checker was:
$ctdb_check_tcp_ports_debug
EOF
		;;
	    *)
		
	esac
    done

    echo "INTERNAL ERROR: ctdb_check_ports - no working checkers in CTDB_TCP_PORT_CHECKERS=\"$CTDB_TCP_PORT_CHECKERS\""

    return 127
}

ctdb_check_tcp_ports_netstat ()
{
    _cmd='netstat -l -t -n'
    _ns=$($_cmd 2>&1)
    if [ $? -eq 127 ] ; then
	# netstat probably not installed - unlikely?
	ctdb_check_tcp_ports_debug="$_ns"
	return 127
    fi

    for _p ; do  # process each function argument (port)
	for _a in '0\.0\.0\.0' '::' ; do
	    _pat="[[:space:]]${_a}:${_p}[[:space:]]+[^[:space:]]+[[:space:]]+LISTEN"
	    if echo "$_ns" | grep -E -q "$_pat" ; then
		# We matched the port, so process next port
		continue 2
	    fi
	done

	# We didn't match the port, so flag an error.
	ctdb_check_tcp_ports_debug="$_cmd shows this output:
$_ns"
	return 1
    done

    return 0
}

ctdb_check_tcp_ports_nmap ()
{
    # nmap wants a comma-separated list of ports
    _ports=""
    for _p ; do
	_ports="${_ports}${_ports:+,}${_p}"
    done

    _cmd="nmap -n -oG - -PS 127.0.0.1 -p $_ports"

    _nmap_out=$($_cmd 2>&1)
    if [ $? -eq 127 ] ; then
	# nmap probably not installed
	ctdb_check_tcp_ports_debug="$_nmap_out"
	return 127
    fi

    # get the port-related output
    _port_info=$(echo "$_nmap_out" | sed -n -r -e 's@^.*Ports:[[:space:]]@@p')

    for _p ; do
	# looking for something like this:
	#  445/open/tcp//microsoft-ds///
	# possibly followed by a comma
	_t="$_p/open/tcp//"
	case "$_port_info" in
	    # The info we're after must be either at the beginning of
	    # the string or it must follow a space.
            $_t*|*\ $_t*) : ;;
	    *)
		# Nope, flag an error...
		ctdb_check_tcp_ports_debug="$_cmd shows this output:
$_nmap_out"
		return 1
	esac
    done

    return 0
}

# Use the new "ctdb checktcpport" command to check the port.
# This is very cheap.
ctdb_check_tcp_ports_ctdb ()
{
    for _p ; do  # process each function argument (port)
	_cmd="ctdb checktcpport $_p"
	_out=$($_cmd 2>&1)
	_ret=$?
	case "$_ret" in
	    0)
		ctdb_check_tcp_ports_debug="\"$_cmd\" was able to bind to port"
		return 1
		;;
	    98)
		# Couldn't bind, something already listening, next port...
		continue
		;;
	    *)
		ctdb_check_tcp_ports_debug="$_cmd (exited with $_ret) with output:
$_out"
		# assume not implemented
		return 127
	esac
    done

    return 0
}

######################################################
# check a unix socket
# usage: ctdb_check_unix_socket SERVICE_NAME <socket_path>
######################################################
ctdb_check_unix_socket() {
    socket_path="$1"
    [ -z "$socket_path" ] && return

    if ! netstat --unix -a -n | grep -q "^unix.*LISTEN.*${socket_path}$"; then
        echo "ERROR: $service_name socket $socket_path not found"
        return 1
    fi
}

######################################################
# check a command returns zero status
# usage: ctdb_check_command SERVICE_NAME <command>
######################################################
ctdb_check_command() {
  service_name="$1"
  wait_cmd="$2"
  [ -z "$wait_cmd" ] && return;
  $wait_cmd > /dev/null 2>&1 || {
      echo "ERROR: $service_name - $wait_cmd returned error"
      exit 1
  }
}

################################################
# kill off any TCP connections with the given IP
################################################
kill_tcp_connections() {
    _IP="$1"    
    _failed=0

    _killcount=0
    connfile="$CTDB_VARDIR/state/connections.$_IP"
    mkdir -p "${connfile%/*}" # dirname
    netstat -tn |egrep "^tcp.*[[:space:]]+$_IP:.*ESTABLISHED" | awk '{print $4" "$5}' > $connfile
    netstat -tn |egrep "^tcp.*[[:space:]]+::ffff:$_IP:.*ESTABLISHED" | awk '{print $4" "$5}' >> $connfile

    while read dest src; do
	srcip=`echo $src | sed -e "s/:[^:]*$//"`
	srcport=`echo $src | sed -e "s/^.*://"`
	destip=`echo $dest | sed -e "s/:[^:]*$//"`
	destport=`echo $dest | sed -e "s/^.*://"`
	echo "Killing TCP connection $srcip:$srcport $destip:$destport"
	ctdb killtcp $srcip:$srcport $destip:$destport >/dev/null 2>&1 || _failed=1
	case $destport in
	  # we only do one-way killtcp for CIFS
	  139|445) : ;;
	  # for all others we do 2-way
	  *) 
	  	ctdb killtcp $destip:$destport $srcip:$srcport >/dev/null 2>&1 || _failed=1
		;;
	esac
	_killcount=`expr $_killcount + 1`
     done < $connfile
    rm -f $connfile

    [ $_failed = 0 ] || {
	echo "Failed to send killtcp control"
	return;
    }
    [ $_killcount -gt 0 ] || {
	return;
    }
    _count=0
    while netstat -tn |egrep "^tcp.*[[:space:]]+$_IP:.*ESTABLISHED" > /dev/null; do
	sleep 1
	_count=`expr $_count + 1`
	[ $_count -gt 3 ] && {
	    echo "Timed out killing tcp connections for IP $_IP"
	    return;
	}
    done
    echo "killed $_killcount TCP connections to released IP $_IP"
}

##################################################################
# kill off the local end for any TCP connections with the given IP
##################################################################
kill_tcp_connections_local_only() {
    _IP="$1"    
    _failed=0

    _killcount=0
    connfile="$CTDB_VARDIR/state/connections.$_IP"
    mkdir -p "${connfile%/*}" # dirname
    netstat -tn |egrep "^tcp.*[[:space:]]+$_IP:.*ESTABLISHED" | awk '{print $4" "$5}' > $connfile
    netstat -tn |egrep "^tcp.*[[:space:]]+::ffff:$_IP:.*ESTABLISHED" | awk '{print $4" "$5}' >> $connfile

    while read dest src; do
	srcip=`echo $src | sed -e "s/:[^:]*$//"`
	srcport=`echo $src | sed -e "s/^.*://"`
	destip=`echo $dest | sed -e "s/:[^:]*$//"`
	destport=`echo $dest | sed -e "s/^.*://"`
	echo "Killing TCP connection $srcip:$srcport $destip:$destport"
	ctdb killtcp $srcip:$srcport $destip:$destport >/dev/null 2>&1 || _failed=1
	_killcount=`expr $_killcount + 1`
     done < $connfile
    rm -f $connfile

    [ $_failed = 0 ] || {
	echo "Failed to send killtcp control"
	return;
    }
    [ $_killcount -gt 0 ] || {
	return;
    }
    _count=0
    while netstat -tn |egrep "^tcp.*[[:space:]]+$_IP:.*ESTABLISHED" > /dev/null; do
	sleep 1
	_count=`expr $_count + 1`
	[ $_count -gt 3 ] && {
	    echo "Timed out killing tcp connections for IP $_IP"
	    return;
	}
    done
    echo "killed $_killcount TCP connections to released IP $_IP"
}

##################################################################
# tickle any TCP connections with the given IP
##################################################################
tickle_tcp_connections() {
    _IP="$1"
    _failed=0

    _killcount=0
    connfile="$CTDB_VARDIR/state/connections.$_IP"
    mkdir -p "${connfile%/*}" # dirname
    netstat -tn |egrep "^tcp.*[[:space:]]+$_IP:.*ESTABLISHED" | awk '{print $4" "$5}' > $connfile
    netstat -tn |egrep "^tcp.*[[:space:]]+::ffff:$_IP:.*ESTABLISHED" | awk '{print $4" "$5}' >> $connfile

    while read dest src; do
	srcip=`echo $src | sed -e "s/:[^:]*$//"`
	srcport=`echo $src | sed -e "s/^.*://"`
	destip=`echo $dest | sed -e "s/:[^:]*$//"`
	destport=`echo $dest | sed -e "s/^.*://"`
	echo "Tickle TCP connection $srcip:$srcport $destip:$destport"
	ctdb tickle $srcip:$srcport $destip:$destport >/dev/null 2>&1 || _failed=1
	echo "Tickle TCP connection $destip:$destport $srcip:$srcport"
	ctdb tickle $destip:$destport $srcip:$srcport >/dev/null 2>&1 || _failed=1
     done < $connfile
    rm -f $connfile

    [ $_failed = 0 ] || {
	echo "Failed to send tickle control"
	return;
    }
}

########################################################
# start/stop the Ganesha nfs service
########################################################
startstop_ganesha()
{
    _service_name="nfs-ganesha-$CTDB_CLUSTER_FILESYSTEM_TYPE"
    case "$1" in
	start)
	    service "$_service_name" start
	    ;;
	stop)
	    service "$_service_name" stop
	    ;;
	restart)
	    service "$_service_name" restart
	    ;;
    esac
}

########################################################
# start/stop the nfs service on different platforms
########################################################
startstop_nfs() {
	PLATFORM="unknown"
	[ -x $CTDB_ETCDIR/init.d/nfsserver ] && {
		PLATFORM="sles"
	}
	[ -x $CTDB_ETCDIR/init.d/nfslock ] && {
		PLATFORM="rhel"
	}

	case $PLATFORM in
	sles)
		case $1 in
		start)
			service nfsserver start
			;;
		stop)
			service nfsserver stop > /dev/null 2>&1
			;;
		restart)
			set_proc "fs/nfsd/threads" 0
			service nfsserver stop > /dev/null 2>&1
			pkill -9 nfsd
			service nfsserver start
			;;
		esac
		;;
	rhel)
		case $1 in
		start)
			service nfslock start
			service nfs start
			;;
		stop)
			service nfs stop
			service nfslock stop
			;;
		restart)
			set_proc "fs/nfsd/threads" 0
			service nfs stop > /dev/null 2>&1
			service nfslock stop > /dev/null 2>&1
			pkill -9 nfsd
			service nfslock start
			service nfs start
			;;
		esac
		;;
	*)
		echo "Unknown platform. NFS is not supported with ctdb"
		exit 1
		;;
	esac
}

########################################################
# start/stop the nfs lockmanager service on different platforms
########################################################
startstop_nfslock() {
	PLATFORM="unknown"
	[ -x $CTDB_ETCDIR/init.d/nfsserver ] && {
		PLATFORM="sles"
	}
	[ -x $CTDB_ETCDIR/init.d/nfslock ] && {
		PLATFORM="rhel"
	}

	case $PLATFORM in
	sles)
		# for sles there is no service for lockmanager
		# so we instead just shutdown/restart nfs
		case $1 in
		start)
			service nfsserver start
			;;
		stop)
			service nfsserver stop > /dev/null 2>&1
			;;
		restart)
			service nfsserver stop
			service nfsserver start
			;;
		esac
		;;
	rhel)
		case $1 in
		start)
			service nfslock start
			;;
		stop)
			service nfslock stop > /dev/null 2>&1
			;;
		restart)
			service nfslock stop
			service nfslock start
			;;
		esac
		;;
	*)
		echo "Unknown platform. NFS locking is not supported with ctdb"
		exit 1
		;;
	esac
}

add_ip_to_iface()
{
    _iface=$1
    _ip=$2
    _maskbits=$3

    _lockfile="${CTDB_VARDIR}/state/interface_modify_${_iface}.flock"
    mkdir -p "${_lockfile%/*}" # dirname
    [ -f "$_lockfile" ] || touch "$_lockfile"

    (
	# Note: use of return/exit/die() below only gets us out of the
	# sub-shell, which is actually what we want.  That is, the
	# function should just return non-zero.

	flock --timeout 30 0 || \
	    die "add_ip_to_iface: unable to get lock for ${_iface}"

	# Ensure interface is up
	ip link set "$_iface" up || \
	    die "Failed to bringup interface $_iface"

	ip addr add "$_ip/$_maskbits" brd + dev "$_iface" || \
	    die "Failed to add $_ip/$_maskbits on dev $_iface"
    ) <"$_lockfile"

    # Do nothing here - return above only gets us out of the subshell
    # and doing anything here will affect the return code.
}

delete_ip_from_iface()
{
    _iface=$1
    _ip=$2
    _maskbits=$3

    _lockfile="${CTDB_VARDIR}/state/interface_modify_${_iface}.flock"
    mkdir -p "${_lockfile%/*}" # dirname
    [ -f "$_lockfile" ] || touch "$_lockfile"

    (
	# Note: use of return/exit/die() below only gets us out of the
	# sub-shell, which is actually what we want.  That is, the
	# function should just return non-zero.

	flock --timeout 30 0 || \
	    die "delete_ip_from_iface: unable to get lock for ${_iface}"

	_im="$_ip/$_maskbits"  # shorthand for readability

	# "ip addr del" will delete all secondary IPs if this is the
	# primary.  To work around this _very_ annoying behaviour we
	# have to keep a record of the secondaries and re-add them
	# afterwards.  Yuck!

	_secondaries=""
	if ip addr list dev "$_iface" primary | grep -Fq "inet $_im " ; then
	    _secondaries=$(ip addr list dev "$_iface" secondary | \
		awk '$1 == "inet" { print $2 }')
	fi

	local _rc=0
	ip addr del "$_im" dev "$_iface" || {
	    echo "Failed to del $_ip on dev $_iface"
	    _rc=1
	}

	if [ -n "$_secondaries" ] ; then
	    for _i in $_secondaries; do
		if ip addr list dev "$_iface" | grep -Fq "inet $_i" ; then
		    echo "Kept secondary $_i on dev $_iface"
		else
		    echo "Re-adding secondary address $_i to dev $_iface"
		    ip addr add $_i brd + dev $_iface || {
			echo "Failed to re-add address $_i to dev $_iface"
			_rc=1
		    }
		fi
	    done
	fi

	return $_rc
    ) <"$_lockfile"

    # Do nothing here - return above only gets us out of the subshell
    # and doing anything here will affect the return code.
}

# If the given IP is hosted then print 2 items: maskbits and iface 
ip_maskbits_iface ()
{
    _addr="$1"

    ip addr show to "${_addr}/32" 2>/dev/null | \
	awk '$1 == "inet" { print gensub(".*/", "", 1, $2), $NF }'
}

drop_ip ()
{
    _addr="${1%/*}"  # Remove optional maskbits
    _log_tag="$2"

    set -- $(ip_maskbits_iface $_addr)
    if [ -n "$1" ] ; then
	_maskbits="$1"
	_iface="$2"
	if [ -n "$_log_tag" ] ; then
	    script_log "$_log_tag" \
		"Removing public address $_addr/$_maskbits from device $_iface"
	fi
	ip addr del $_addr/$_maskbits dev $_iface >/dev/null 2>&1
    fi
}

drop_all_public_ips ()
{
    _log_tag="$1"

    while read _ip _x ; do
	drop_ip "$_ip" "$_log_tag"
    done <"${CTDB_PUBLIC_ADDRESSES:-/dev/null}"
}

########################################################
# some simple logic for counting events - per eventscript
# usage: ctdb_counter_init
#        ctdb_counter_incr
#        ctdb_check_counter_limit <limit>
# ctdb_check_counter_limit fails when count >= <limit>
########################################################
_ctdb_counter_common () {
    _service_name="${1:-${service_name}}"
    _counter_file="$ctdb_fail_dir/$_service_name"
    mkdir -p "${_counter_file%/*}" # dirname
}
ctdb_counter_init () {
    _ctdb_counter_common "$1"

    >"$_counter_file"
}
ctdb_counter_incr () {
    _ctdb_counter_common "$1"

    # unary counting!
    echo -n 1 >> "$_counter_file"
}
ctdb_check_counter_limit () {
    _ctdb_counter_common

    _limit="${1:-${service_fail_limit}}"
    _quiet="$2"

    # unary counting!
    _size=$(stat -c "%s" "$_counter_file" 2>/dev/null || echo 0)
    if [ $_size -ge $_limit ] ; then
	echo "ERROR: more than $_limit consecutive failures for $service_name, marking cluster unhealthy"
	exit 1
    elif [ $_size -gt 0 -a -z "$_quiet" ] ; then
	echo "WARNING: less than $_limit consecutive failures ($_size) for $service_name, not unhealthy yet"
    fi
}
ctdb_check_counter () {
    _msg="${1:-error}"  # "error"  - anything else is silent on fail
    _op="${2:--ge}"  # an integer operator supported by test
    _limit="${3:-${service_fail_limit}}"
    shift 3
    _ctdb_counter_common "$1"

    # unary counting!
    _size=$(stat -c "%s" "$_counter_file" 2>/dev/null || echo 0)
    if [ $_size $_op $_limit ] ; then
	if [ "$_msg" = "error" ] ; then
	    echo "ERROR: $_limit consecutive failures for $_service_name, marking node unhealthy"
	    exit 1		
	else
	    return 1
	fi
    fi
}

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

ctdb_status_dir="$CTDB_VARDIR/status"
ctdb_fail_dir="$CTDB_VARDIR/failcount"

ctdb_setup_service_state_dir ()
{
    service_state_dir="$CTDB_VARDIR/state/${1:-${service_name}}"
    mkdir -p "$service_state_dir" || {
	echo "Error creating state dir \"$service_state_dir\""
	exit 1
    }
}

########################################################
# Managed status history, for auto-start/stop

ctdb_managed_dir="$CTDB_VARDIR/managed_history"

_ctdb_managed_common ()
{
    _service_name="${1:-${service_name}}"
    _ctdb_managed_file="$ctdb_managed_dir/$_service_name"
}

ctdb_service_managed ()
{
    _ctdb_managed_common "$@"
    mkdir -p "$ctdb_managed_dir"
    touch "$_ctdb_managed_file"
}

ctdb_service_unmanaged ()
{
    _ctdb_managed_common "$@"
    rm -f "$_ctdb_managed_file"
}

is_ctdb_previously_managed_service ()
{
    _ctdb_managed_common "$@"
    [ -f "$_ctdb_managed_file" ]
}

########################################################
# Check and set status

log_status_cat ()
{
    echo "node is \"$1\", \"${script_name}\" reports problem: $(cat $2)"
}

ctdb_checkstatus ()
{
    if [ -r "$ctdb_status_dir/$script_name/unhealthy" ] ; then
	log_status_cat "unhealthy" "$ctdb_status_dir/$script_name/unhealthy"
	return 1
    elif [ -r "$ctdb_status_dir/$script_name/banned" ] ; then
	log_status_cat "banned" "$ctdb_status_dir/$script_name/banned"
	return 2
    else
	return 0
    fi
}

ctdb_setstatus ()
{
    d="$ctdb_status_dir/$script_name"
    case "$1" in
	unhealthy|banned)
	    mkdir -p "$d"
	    cat "$2" >"$d/$1"
	    ;;
	*)
	    for i in "banned" "unhealthy" ; do
		rm -f "$d/$i"
	    done
	    ;;
    esac
}

##################################################################
# Reconfigure a service on demand

_ctdb_service_reconfigure_common ()
{
    _d="$ctdb_status_dir/${service_name}"
    mkdir -p "$_d"
    _ctdb_service_reconfigure_flag="$_d/reconfigure"
}

ctdb_service_needs_reconfigure ()
{
    _ctdb_service_reconfigure_common
    [ -e "$_ctdb_service_reconfigure_flag" ]
}

ctdb_service_set_reconfigure ()
{
    _ctdb_service_reconfigure_common
    >"$_ctdb_service_reconfigure_flag"
}

ctdb_service_unset_reconfigure ()
{
    _ctdb_service_reconfigure_common
    rm -f "$_ctdb_service_reconfigure_flag"
}

ctdb_service_reconfigure ()
{
    echo "Reconfiguring service \"${service_name}\"..."
    ctdb_service_unset_reconfigure
    service_reconfigure || return $?
    ctdb_counter_init
}

# Default service_reconfigure() function does nothing.
service_reconfigure ()
{
    :
}

ctdb_reconfigure_try_lock ()
{
    _ctdb_service_reconfigure_common
    _lock="${_d}/reconfigure_lock"
    mkdir -p "${_lock%/*}" # dirname
    touch "$_lock"

    (
	flock 0
	# This is overkill but will work if we need to extend this to
	# allow certain events to run multiple times in parallel
	# (e.g. takeip) and write multiple PIDs to the file.
	read _locker_event 
	if [ -n "$_locker_event" ] ; then
	    while read _pid ; do
		if [ -n "$_pid" -a "$_pid" != $$ ] && \
		    kill -0 "$_pid" 2>/dev/null ; then
		    exit 1
		fi
	    done
	fi

	printf "%s\n%s\n" "$event_name" $$ >"$_lock"
	exit 0
    ) <"$_lock"
}

ctdb_replay_monitor_status ()
{
    echo "Replaying previous status for this script due to reconfigure..."
    # Leading colon (':') is missing in some versions...
    _out=$(ctdb scriptstatus -Y | grep -E "^:?monitor:${script_name}:")
    # Output looks like this:
    # :monitor:60.nfs:1:ERROR:1314764004.030861:1314764004.035514:foo bar:
    # This is the cheapest way of getting fields in the middle.
    set -- $(IFS=":" ; echo $_out)
    _code="$3"
    _status="$4"
    # The error output field can include colons so we'll try to
    # preserve them.  The weak checking at the beginning tries to make
    # this work for both broken (no leading ':') and fixed output.
    _out="${_out%:}"
    _err_out="${_out#*monitor:${script_name}:*:*:*:*:}"
    case "$_status" in
	OK) : ;;  # Do nothing special.
	TIMEDOUT)
	    # Recast this as an error, since we can't exit with the
	    # correct negative number.
	    _code=1
	    _err_out="[Replay of TIMEDOUT scriptstatus - note incorrect return code.] ${_err_out}"
	    ;;
	DISABLED)
	    # Recast this as an OK, since we can't exit with the
	    # correct negative number.
	    _code=0
	    _err_out="[Replay of DISABLED scriptstatus - note incorrect return code.] ${_err_out}"
	    ;;
	*) : ;;  # Must be ERROR, do nothing special.
    esac
    echo "$_err_out"
    exit $_code
}

ctdb_service_check_reconfigure ()
{
    # We only care about some events in this function.  For others we
    # return now.
    case "$event_name" in
	monitor|ipreallocated|reconfigure) : ;;
	*) return 0 ;;
    esac

    if ctdb_reconfigure_try_lock ; then
	# No events covered by this function are running, so proceed
	# with gay abandon.
	case "$event_name" in
	    reconfigure)
		(ctdb_service_reconfigure)
		exit $?
		;;
	    ipreallocated)
		if ctdb_service_needs_reconfigure ; then
		    ctdb_service_reconfigure
		fi
		;;
	    monitor)
		if ctdb_service_needs_reconfigure ; then
		    ctdb_service_reconfigure
		    # Given that the reconfigure might not have
		    # resulted in the service being stable yet, we
		    # replay the previous status since that's the best
		    # information we have.
		    ctdb_replay_monitor_status
		fi
		;;
	esac
    else
	# Somebody else is running an event we don't want to collide
	# with.  We proceed with caution.
	case "$event_name" in
	    reconfigure)
		# Tell whoever called us to retry.
		exit 2
		;;
	    ipreallocated)
		# Defer any scheduled reconfigure and just run the
		# rest of the ipreallocated event, as per the
		# eventscript.  There's an assumption here that the
		# event doesn't depend on any scheduled reconfigure.
		# This is true in the current code.
		return 0
		;;
	    monitor)
		# There is most likely a reconfigure in progress so
		# the service is possibly unstable.  As above, we
		# defer any scheduled reconfigured.  We also replay
		# the previous monitor status since that's the best
		# information we have.
		ctdb_replay_monitor_status
		;;
	esac
    fi
}

##################################################################
# Does CTDB manage this service? - and associated auto-start/stop

ctdb_compat_managed_service ()
{
    if [ "$1" = "yes" -a "$2" = "$_service_name" ] ; then
	CTDB_MANAGED_SERVICES="$CTDB_MANAGED_SERVICES $2"
    fi
}

is_ctdb_managed_service ()
{
    _service_name="${1:-${service_name}}"

    # $t is used just for readability and to allow better accurate
    # matching via leading/trailing spaces
    t=" $CTDB_MANAGED_SERVICES "

    # Return 0 if "<space>$_service_name<space>" appears in $t
    if [ "${t#* ${_service_name} }" != "${t}" ] ; then
	return 0
    fi

    # If above didn't match then update $CTDB_MANAGED_SERVICES for
    # backward compatibility and try again.
    ctdb_compat_managed_service "$CTDB_MANAGES_VSFTPD"   "vsftpd"
    ctdb_compat_managed_service "$CTDB_MANAGES_SAMBA"    "samba"
    ctdb_compat_managed_service "$CTDB_MANAGES_SCP"      "scp"
    ctdb_compat_managed_service "$CTDB_MANAGES_WINBIND"  "winbind"
    ctdb_compat_managed_service "$CTDB_MANAGES_HTTPD"    "apache2"
    ctdb_compat_managed_service "$CTDB_MANAGES_HTTPD"    "httpd"
    ctdb_compat_managed_service "$CTDB_MANAGES_ISCSI"    "iscsi"
    ctdb_compat_managed_service "$CTDB_MANAGES_CLAMD"    "clamd"
    ctdb_compat_managed_service "$CTDB_MANAGES_NFS"      "nfs"
    ctdb_compat_managed_service "$CTDB_MANAGES_NFS"      "nfs-ganesha-gpfs"

    t=" $CTDB_MANAGED_SERVICES "

    # Return 0 if "<space>$_service_name<space>" appears in $t
    [ "${t#* ${_service_name} }" != "${t}" ]
}

ctdb_start_stop_service ()
{
    _service_name="${1:-${service_name}}"

    # Allow service-start/service-stop pseudo-events to start/stop
    # services when we're not auto-starting/stopping and we're not
    # monitoring.
    case "$event_name" in
	service-start)
	    if is_ctdb_managed_service "$_service_name" ; then
		die 'service-start event not permitted when service is managed'
	    fi
	    if [ "$CTDB_SERVICE_AUTOSTARTSTOP" = "yes" ] ; then
		die 'service-start event not permitted with $CTDB_SERVICE_AUTOSTARTSTOP = yes'
	    fi
	    ctdb_service_start "$_service_name"
	    exit $?
	    ;;
	service-stop)
	    if is_ctdb_managed_service "$_service_name" ; then
		die 'service-stop event not permitted when service is managed'
	    fi
	    if [ "$CTDB_SERVICE_AUTOSTARTSTOP" = "yes" ] ; then
		die 'service-stop event not permitted with $CTDB_SERVICE_AUTOSTARTSTOP = yes'
	    fi
	    ctdb_service_stop "$_service_name"
	    exit $?
	    ;;
    esac

    # Do nothing unless configured to...
    [ "$CTDB_SERVICE_AUTOSTARTSTOP" = "yes" ] || return 0

    [ "$event_name" = "monitor" ] || return 0

    if is_ctdb_managed_service "$_service_name" ; then
	if ! is_ctdb_previously_managed_service "$_service_name" ; then
	    echo "Starting service \"$_service_name\" - now managed"
	    background_with_logging ctdb_service_start "$_service_name"
	    exit $?
	fi
    else
	if is_ctdb_previously_managed_service "$_service_name" ; then
	    echo "Stopping service \"$_service_name\" - no longer managed"
	    background_with_logging ctdb_service_stop "$_service_name"
	    exit $?
	fi
    fi
}

ctdb_service_start ()
{
    # The service is marked managed if we've ever tried to start it.
    ctdb_service_managed "$@"

    # Here we only want $1.  If no argument is passed then
    # service_start needs to know.
    service_start "$@" || return $?

    ctdb_counter_init "$@"
    ctdb_check_tcp_init
}

ctdb_service_stop ()
{
    ctdb_service_unmanaged "$@"
    service_stop "$@"
}

# Default service_start() and service_stop() functions.
 
# These may be overridden in an eventscript.  When overriding, the
# following convention must be followed.  If these functions are
# called with no arguments then they may use internal logic to
# determine whether the service is managed and, therefore, whether
# they should take any action.  However, if the service name is
# specified as an argument then an attempt must be made to start or
# stop the service.  This is because the auto-start/stop code calls
# them with the service name as an argument.
service_start ()
{
    service "${1:-${service_name}}" start
}

service_stop ()
{
    service "${1:-${service_name}}" stop
}

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

ctdb_standard_event_handler ()
{
    case "$1" in
	status)
	    ctdb_checkstatus
	    exit
	    ;;
	setstatus)
            shift
	    ctdb_setstatus "$@"
	    exit
	    ;;
    esac
}

# iptables doesn't like being re-entered, so flock-wrap it.
iptables()
{
	flock -w 30 $CTDB_VARDIR/iptables-ctdb.flock /sbin/iptables "$@"
}

########################################################
# tickle handling
########################################################

update_tickles ()
{
	_port="$1"

	tickledir="$CTDB_VARDIR/state/tickles"
	mkdir -p "$tickledir"

	# Who am I?
	_pnn=$(ctdb pnn) ; _pnn=${_pnn#PNN:}

	# What public IPs do I hold?
	_ips=$(ctdb -Y ip | awk -F: -v pnn=$_pnn '$3 == pnn {print $2}')

	# IPs as a regexp choice
	_ipschoice="($(echo $_ips | sed -e 's/ /|/g' -e 's/\./\\\\./g'))"

	# Record connections to our public IPs in a temporary file
	_my_connections="${tickledir}/${_port}.connections"
	rm -f "$_my_connections"
	netstat -tn |
	awk -v destpat="^${_ipschoice}:${_port}\$" \
	  '$1 == "tcp" && $6 == "ESTABLISHED" && $4 ~ destpat {print $5, $4}' |
	sort >"$_my_connections"

	# Record our current tickles in a temporary file
	_my_tickles="${tickledir}/${_port}.tickles"
	rm -f "$_my_tickles"
	for _i in $_ips ; do
		ctdb -Y gettickles $_i $_port | 
		awk -F: 'NR > 1 { printf "%s:%s %s:%s\n", $2, $3, $4, $5 }'
	done |
	sort >"$_my_tickles"

	# Add tickles for connections that we haven't already got tickles for
	comm -23 "$_my_connections" "$_my_tickles" |
	while read _src _dst ; do
		ctdb addtickle $_src $_dst
	done

	# Remove tickles for connections that are no longer there
	comm -13 "$_my_connections" "$_my_tickles" |
	while read _src _dst ; do
		ctdb deltickle $_src $_dst
	done

	rm -f "$_my_connections" "$_my_tickles" 
}

########################################################
# load a site local config file
########################################################

[ -n "$CTDB_RC_LOCAL" -a -x "$CTDB_RC_LOCAL" ] && {
	. "$CTDB_RC_LOCAL"
}

[ -x $CTDB_BASE/rc.local ] && {
	. $CTDB_BASE/rc.local
}

[ -d $CTDB_BASE/rc.local.d ] && {
	for i in $CTDB_BASE/rc.local.d/* ; do
		[ -x "$i" ] && . "$i"
	done
}

script_name="${0##*/}"       # basename
service_name="$script_name"  # default is just the script name
service_fail_limit=1
event_name="$1"