#!/bin/sh
#
# ltsp-client-swap  Setup/Turn on swaps for the LTSP client.
#
# chkconfig: 2345 01 64
# description: LTSP client's swap initialization
# config: /usr/share/ltsp/ltsp_config
# pidfile: /var/run/ltsp-client-setip.pid

# Do not load RH compatibility interface.
WITHOUT_RC_COMPAT=1

# Source function library.
. /etc/init.d/functions

# Source configuration.
SourceIfNotEmpty /etc/default/ltsp-client-setup

LOCKFILE=/var/lock/subsys/ltsp-client-swap
RETVAL=0

SourceIfNotEmpty /usr/share/ltsp/ltsp-client-functions
[ -f /etc/ltsp_chroot ] && SourceIfNotEmpty /usr/share/ltsp/ltsp_config || exit 0

FST=`which fstyp 2>/dev/null` || FST=`which fstype 2>/dev/null` || FST=`which sfdisk 2>/dev/null` || FST=`which fdisk 2>/dev/null` || FST=`which file 2>/dev/null`

make_dev()
{
    local dev type major minor
    dev=$1
    type=$2
    major=$3
    minor=$4
    if service udevd status >/dev/null; then
	udevsettle --timeout=5 && test -$type $dev
	return $?
    else
	mknod -m 640 $dev $type $major $minor && chgrp disk $dev
	return $?
    fi
}

compcache()
{
    local K Size Free MinFree MemRes
    is_no $1 && return 0
    K=1024
    MinFree=$((16 * $K))
    MemRes=$((2 * $K))
    Free=$(($(MemInfo MemFree) + $(MemInfo Cached)))
    case $1 in
	*[0-9])
	    Size=$1
	    ;;
	*[kK])
	    Size=${1%[kK]}
	    ;;
	*[mM])
	    Size=$((${1%[mM]} * $K))
	    ;;
	*%)
	    Size=$(($(MemInfo MemTotal) * 100 / ${1%\%}))
	    ;;
	*)
	    Size=$(($Free / 2))
	    ;;
    esac
    if [ -n "$Size" ]; then
	[ $(($Free - $Size)) -lt $MinFree ] && Size=$(($Free - $MinFree))
	Free=$(MemInfo MemFree)
	[ $Free -lt $(($Size + $MemRes)) ] && Size=$(($Free - $MemRes))
	modprobe -q compcache compcache_size_kbytes=$Size &&
	    make_dev /dev/ramzswap0 b 251 0 &&
		echo "/dev/ramzswap0 swap swap pri=255 0 0" >> /etc/fstab
    fi
}

is_swap()
{
    if [ -n "$FST" -a -n "$1" ]; then
	case "$FST" in
	    */fstyp)
		FSTYPE=`$FST /dev/$1 2>/dev/null`
		[ -n "$FSTYPE" -a "$FSTYPE" = "swap" ] && return 0
		;;
	    */fstype)
		FSTYPE=`$FST -d /dev/$1 2>/dev/null`
		[ -n "$FSTYPE" -a "$FSTYPE" = "swap" ] && return 0
		;;
	    */*fdisk)
		$FST -l 2>/dev/null | egrep '^/dev/$1 [[:blank:]]+.*[[:blank:]]+Linux swap' && return 0
		;;
	    */file)
		file -s /dev/$1 2>/dev/null | grep -q 'Linux.*swap' && return 0
		;;
	esac
    fi
    return 1;
}

get_ip()
{
    ip addr show ${1:-eth0} | sed -n -r '/^[[:blank:]]*inet /s|^[[:blank:]]*inet[[:blank:]]*(.*)/.*$|\1|p'
}

add_swap()
{
    [ -z "$1" ] || mkswap $1 && echo "$1 swap swap ${2:-defaults} 0 0" >> /etc/fstab
}

nfs_swap()
{
    local nswap
    if mkdir -p /mnt/nfsswap; then
	if mount -n -o nolock,proto=udp ${SWAP_SERVER:-$SERVER}:${SWAP_DIR:-/var/spool/ltspswap} /mnt/nfsswap; then
	    nswap="/mnt/nfsswap/$(get_ip).swap"
	    rm -f $nswap
	    dd if=/dev/zero of=$nswap bs=1M count=${SWAP_SIZE:-128} && add_swap $nswap
	else
	    rmdir /mnt/nfsswap
	fi
    fi
}

nbd_swap()
{
    local nswap i
    if modprobe -q nbd nbds_max=2; then
	make_dev /dev/nbd1 b 43 1 && nswap=nbd1 || nswap=
	if [ -n "$nswap" ] && nbd-client ${SWAP_SERVER:-$SERVER} ${NBD_PORT:-9210} /dev/$nswap; then
	    if is_yes "$ENCRYPT_SWAP"; then
		if [ -x /usr/sbin/cryptsetup ]; then
		    if modprobe -q dm_crypt; then
			if cryptsetup -d /dev/urandom create cswap $nswap; then
			    nswap="mapper/cswap"
			else
			    modprobe -qr dm_crypt
			    echo "ERROR: ENCRYPT_SWAP=Y, but can't cteate encryptrd swap. Disabling encryption."
			    ENCRYPT_SWAP="N"
			fi
		    else
			echo "ERROR: ENCRYPT_SWAP=Y, but dm_crypt module not found. Disabling encryption."
			ENCRYPT_SWAP="N"
		    fi
		else
		    echo "ERROR: ENCRYPT_SWAP=Y, but cryptsetup not found. Disabling encryption."
		    ENCRYPT_SWAP="N"
		fi
	    fi
	    is_yes "$ENCRYPT_SWAP" || modprobe -qr dm_mod 
	    add_swap /dev/$nswap
	else
	    modprobe -qr nbd
	fi
    fi
}

local_swap()
{
    # Enable local swap partition if found on local disk
    for part in `grep '[[:digit:]]$' /proc/partitions | sed -r -e 's/.*[[:blank:]]+([[:graph:]]+)$/\1/'`; do
	is_swap $part && add_swap /dev/$part
    done
}

start()
{
    if [ -f "$LOCKFILE" ]; then
	msg_already_running "ltsp-client-swap"
	RETVAL=1
    else
	msg_starting $"Starting LTSP swaps"
	[ -z "$COMPCACHE" ] || compcache $COMPCACHE
	is_yes "$USE_LOCAL_SWAP" && local_swap
	is_yes "$NBD_SWAP" && nbd_swap
	is_yes "$NFS_SWAP" && nfs_swap
	swapon -a
	RETVAL=$?
    fi
    touch "$LOCKFILE"
    return $RETVAL
}

stop()
{
    swapoff -a
    RETVAL=$?
    rm -f "$LOCKFILE"
    return $RETVAL
}

status()
{
    if [ -f "$LOCKFILE" ]; then
	swapon -s
    else
	echo "This service hasn't been started since stopped last time."
    fi
    RETVAL=$?
    return $RETVAL
}

condrestart()
{
    stop
    swapon -a
    RETVAL=$?
    return $RETVAL
}

case "$1" in
    start|restart|reload)
	start
	;;
    condrestart|condreload)
	# Nothing to do on condrestart
	condrestart
	;;
    stop|condstop)
	stop
	;;
    status)
	status
	;;
    *)
	msg_usage "${0##*/} {start|stop|restart|reload|status|condrestart|condreload|condstop}"
	RETVAL=1
	;;
esac

exit $RETVAL