#!/bin/sh

# Event script for ctdb-specific setup and other things that don't fit
# elsewhere.

[ -n "$CTDB_BASE" ] || \
    export CTDB_BASE=$(cd -P $(dirname "$0") ; dirname "$PWD")

. $CTDB_BASE/functions
loadconfig

ctdb_setup_service_state_dir "ctdb"

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

select_tdb_checker ()
{
    # Find the best TDB consistency check available.
    use_tdb_tool_check=false
    if which tdbtool >/dev/null 2>&1 && \
	echo "help" | tdbtool | grep -q check ; then

	use_tdb_tool_check=true
    elif which tdbtool >/dev/null 2>&1 && which tdbdump >/dev/null 2>&1 ; then
	    cat <<EOF
WARNING: The installed 'tdbtool' does not offer the 'check' subcommand.
 Using 'tdbdump' for database checks.
 Consider updating 'tdbtool' for better checks!
EOF
    elif which tdbdump >/dev/null 2>&1 ; then
	cat <<EOF
WARNING: 'tdbtool' is not available.
 Using 'tdbdump' to check the databases.
 Consider installing a recent 'tdbtool' for better checks!
EOF
    else
	cat <<EOF
WARNING: Cannot check databases since neither
 'tdbdump' nor 'tdbtool check' is available.
 Consider installing tdbtool or at least tdbdump!
EOF
        return 1
    fi
}

check_tdb ()
{
    _db="$1"

    if $use_tdb_tool_check ; then
	# tdbtool always exits with 0  :-(
	if tdbtool "$_db" check 2>/dev/null |
	    grep -q "Database integrity is OK" ; then
	    return 0
	else
	    return 1
	fi
    else
	tdbdump "$_db" >/dev/null 2>/dev/null
	return $?
    fi
}

check_persistent_databases ()
{
    _dir="${CTDB_DBDIR_PERSISTENT:-${CTDB_DBDIR:-${CTDB_VARDIR}}/persistent}"
    mkdir -p "$_dir" 2>/dev/null

    [ "${CTDB_MAX_PERSISTENT_CHECK_ERRORS:-0}" = "0" ] || return 0

    for _db in $(ls "$_dir/"*.tdb.*[0-9] 2>/dev/null) ; do
	check_tdb $_db || {
	    echo "Persistent database $_db is corrupted! CTDB will not start."
	    return 1
	}
    done
}

check_non_persistent_databases ()
{
    _dir="${CTDB_DBDIR:-${CTDB_VARDIR}}"
    mkdir -p "$_dir" 2>/dev/null

    for _db in $(ls "${_dir}/"*.tdb.*[0-9] 2>/dev/null) ; do
	check_tdb $_db || {
	    _backup="${_db}.$(date +'%Y%m%d.%H%M%S.%N').corrupt"
	    cat <<EOF
WARNING: database ${_db} is corrupted.
 Moving to backup ${_backup} for later analysis.
EOF
	    mv "$_db" "$_backup"

	    # Now remove excess backups
	    ls -td "${_db}."*".corrupt" |
	    tail -n +$((${CTDB_MAX_CORRUPT_DB_BACKUPS:-10} + 1)) |
	    xargs rm -f
	    
	}
    done
}

update_config_from_tdb() {

    # Pull optional ctdb configuration data out of config.tdb
    _key="public_addresses:node#$(ctdb -t 1 xpnn|sed -e 's/.*://')"
    _t="$service_state_dir/public_addresses"
    rm -f "$_t"

    if ctdb pfetch config.tdb "$_key" "$_t" 2>/dev/null && \
	[ -s "$_t" -a -n "$CTDB_PUBLIC_ADDRESSES"] && \
	! cmp -s "$_t" "$CTDB_PUBLIC_ADDRESSES" ; then

	echo "CTDB public address configuration has changed."
	echo "Extracting new configuration from database."
	diff "$_t" "$CTDB_PUBLIC_ADDRESSES"
	cp "$_t" "$CTDB_PUBLIC_ADDRESSES"
	echo "Restarting CTDB"
	service ctdb restart &
    fi
}

set_ctdb_variables () {
    # set any tunables from the config file
    set | grep ^CTDB_SET_ | cut -d_ -f3- | 
    while read v; do
	varname=`echo $v | cut -d= -f1`
	value=`echo $v | cut -d= -f2`
	ctdb setvar $varname $value || return 1
	echo "Set $varname to $value"
    done
}

monitor_system_memory ()
{
    # If monitoring free memory then calculate how much there is
    if [ -n "$CTDB_MONITOR_FREE_MEMORY_WARN" -o \
	-n "$CTDB_MONITOR_FREE_MEMORY" ] ; then
	free_mem=$(free -m | awk '$2 == "buffers/cache:" { print $4 }')
    fi

    # Shutdown CTDB when memory is below the configured limit
    if [ -n "$CTDB_MONITOR_FREE_MEMORY" ] ; then
	if [ $free_mem -le $CTDB_MONITOR_FREE_MEMORY ] ; then
	    echo "CRITICAL: OOM - ${free_mem}MB free <= ${CTDB_MONITOR_FREE_MEMORY}MB (CTDB threshold)"
	    echo "CRITICAL: Shutting down CTDB!!!"
	    get_proc "meminfo"
	    ps auxfww
	    set_proc "sysrq-trigger" "m"
	    ctdb disable
	    sleep 3
	    ctdb shutdown
	fi
    fi

    # Warn when low on memory
    if [ -n "$CTDB_MONITOR_FREE_MEMORY_WARN" ] ; then
	if [ $free_mem -le $CTDB_MONITOR_FREE_MEMORY_WARN ] ; then
	    echo "WARNING: free memory is low - ${free_mem}MB free <=  ${CTDB_MONITOR_FREE_MEMORY_WARN}MB (CTDB threshold)"
	fi
    fi

    # We should never enter swap, so SwapTotal == SwapFree.
    if [ "$CTDB_CHECK_SWAP_IS_NOT_USED" = "yes" ] ; then
	set -- $(get_proc "meminfo" | awk '$1 ~ /Swap(Total|Free):/ { print $2 }')
	if [ "$1" != "$2" ] ; then
	    echo We are swapping:
	    get_proc "meminfo"
	    ps auxfww
	fi
    fi
}

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

ctdb_check_args "$@"

case "$1" in 
     init)
        # make sure we have a blank state directory for the scripts to work with
	rm -rf $CTDB_VARDIR/state
	# Look at the pattern - this should not be -rf!!!
	rm -f $ctdb_managed_dir/*
	mkdir -p $CTDB_VARDIR/state || {
	    ret=$?
	    echo "mkdir -p $CTDB_VARDIR/state - failed - $ret"
	    exit $ret
	}

	# make sure we drop any ips that might still be held if
	# previous instance of ctdb got killed with -9 or similar
	drop_all_public_ips

	if select_tdb_checker ; then
	    check_persistent_databases || exit $?
	    check_non_persistent_databases
	fi
	;;

    setup)
	# Set any tunables from the config file
	set_ctdb_variables || die "Failed to set CTDB tunables"
	;;

    startup)
	ctdb attach ctdb.tdb persistent
	update_config_from_tdb &
	;;
    monitor)
	monitor_system_memory
	;;

    *)
	ctdb_standard_event_handler "$@"
	;;
esac

# all OK
exit 0