#!/bin/sh
# script to manage nfs in a clustered environment

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

. "${CTDB_BASE}/functions"

# service_name is used by various functions
# shellcheck disable=SC2034
service_name="nfs"

loadconfig
service_state_dir=$(ctdb_setup_service_state_dir) || exit $?

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

service_reconfigure ()
{
    # Restart lock manager, notify clients
    if [ -x "${CTDB_BASE}/statd-callout" ] ; then
	"${CTDB_BASE}/statd-callout" notify &
    fi >/dev/null 2>&1
}

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

######################################################
# Check the health of NFS services
#
# Use .check files in $CTDB_NFS_CHECKS_DIR.
# Default is "${CTDB_BASE}/nfs-checks.d/"
######################################################
nfs_check_services ()
{
    _dir="${CTDB_NFS_CHECKS_DIR:-${CTDB_BASE}/nfs-checks.d}"

    # Files must end with .check - avoids editor backups, RPM fu, ...
    for _f in "$_dir"/[0-9][0-9].*.check ; do
	_t="${_f%.check}"
	_progname="${_t##*/[0-9][0-9].}"

	nfs_check_service "$_progname" <"$_f"
    done
}

######################################################
# Check the health of an NFS service
#
# $1 - progname, passed to rpcinfo (looked up in /etc/rpc)
#
# Reads variables from stdin
#
# Variables are:
#
# * family             - "tcp" or "udp" or space separated list
#                        default: tcp, not used with "service_check_cmd"
# * version            - optional, RPC service version number
#                        default is to omit to check for any version,
#                        not used with "service_check_cmd"
# * unhealthy_after    - number of check fails before unhealthy
#                        default: 1
# * restart_every      - number of check fails before restart
#                        default: 0, meaning no restart
# * service_stop_cmd   - command to stop service
#                        default: no default, must be provided if
#                                 restart_every > 0
# * service_start_cmd  - command to start service
#                        default: no default, must be provided if
#                                 restart_every > 0
# * service_check_cmd  - command to check health of service
#                        default is to check RPC service using rpcinfo
# * service_debug_cmd  - command to debug a service after trying to stop it;
#                        for example, it can be useful to print stack
#                        traces of threads that have not exited, since
#                        they may be stuck doing I/O;
#                        no default, see also function program_stack_traces()
#
# Quoting in values is not preserved
#
######################################################
nfs_check_service ()
{
    _progname="$1"

    # This sub-shell is created to intentionally limit the scope of
    # variable values read from the .check files.
    # shellcheck disable=SC2030
    (
	# Subshell to restrict scope variables...

	# Defaults
	family="tcp"
	version=""
	unhealthy_after=1
	restart_every=0
	service_stop_cmd=""
	service_start_cmd=""
	service_check_cmd=""
	service_debug_cmd=""

	# Eval line-by-line.  Expands variable references in values.
	# Also allows variable name checking, which seems useful.
	while read _line ; do
	    case "$_line" in
		\#*|"") : ;; # Ignore comments, blank lines

		family=*|version=*|\
		unhealthy_after=*|restart_every=*|\
		service_stop_cmd=*|service_start_cmd=*|\
		service_check_cmd=*|service_debug_cmd=*)

		    eval "$_line"
		    ;;
		*)
		    echo "ERROR: Unknown variable for ${_progname}: ${_line}"
		    exit 1
	    esac
	done

	_service_name="nfs_${_progname}"

	_ok=false
	if [ -n "$service_check_cmd" ] ; then
	    # Using eval means variables can contain semicolon separated commands
	    if eval "$service_check_cmd" ; then
		_ok=true
	    else
		_err="monitoring service \"${_progname}\" failed"
	    fi
	else
	    if nfs_check_rpcinfo \
		   "$_progname" "$version" "$family" >/dev/null ; then
		_ok=true
	    else
		_err="$ctdb_check_rpc_out"
	    fi
	fi

	if $_ok ; then
	    if [ $unhealthy_after -ne 1 -o $restart_every -ne 0 ] ; then
		ctdb_counter_init "$_service_name"
	    fi
	    exit 0
	fi

	ctdb_counter_incr "$_service_name"
	_failcount=$(ctdb_counter_get "$_service_name")

	_unhealthy=false
	if [ "$unhealthy_after" -gt 0 ] ; then
	    if [ "$_failcount" -ge "$unhealthy_after" ] ; then
		_unhealthy=true
		echo "ERROR: $_err"
	    fi
	fi

	if [ "$restart_every" -gt 0 ] ; then
	    if [ $((_failcount % restart_every)) -eq 0 ] ; then
		if ! $_unhealthy ; then
		    echo "WARNING: $_err"
		fi
		nfs_restart_service
	    fi
	fi

	if $_unhealthy ; then
	    exit 1
	fi

	return 0
    ) || exit 1
}

# Uses: service_stop_cmd, service_start_cmd, service_debug_cmd
# This function is called within the sub-shell that shellcheck thinks
# loses the above variable values.
# shellcheck disable=SC2031
nfs_restart_service ()
{
    if [ -z "$service_stop_cmd" -o -z "$service_start_cmd" ] ; then
	die "ERROR: Can not restart service \"${_progname}\" without corresponding service_start_cmd/service_stop_cmd settings"
    fi

    echo "Trying to restart service \"${_progname}\"..."
    # Using eval means variables can contain semicolon separated commands
    eval "$service_stop_cmd"
    if [ -n "$service_debug_cmd" ] ; then
	eval "$service_debug_cmd"
    fi
    background_with_logging eval "$service_start_cmd"
}

######################################################
# Check an RPC service with rpcinfo
######################################################
ctdb_check_rpc ()
{
    _progname="$1"        # passed to rpcinfo (looked up in /etc/rpc)
    _version="$2"         # optional, not passed if empty/unset
    _family="${3:-tcp}"   # optional, default is "tcp"

    case "$_family" in
	tcp6|udp6)
	    _localhost="${CTDB_RPCINFO_LOCALHOST6:-::1}"
	    ;;
	*)
	    _localhost="${CTDB_RPCINFO_LOCALHOST:-127.0.0.1}"
    esac

    # $_version is not quoted because it is optional
    # shellcheck disable=SC2086
    if ! ctdb_check_rpc_out=$(rpcinfo -T "$_family" "$_localhost" \
				      "$_progname" $_version 2>&1) ; then
	ctdb_check_rpc_out="$_progname failed RPC check:
$ctdb_check_rpc_out"
	echo "$ctdb_check_rpc_out"
	return 1
    fi
}

nfs_check_rpcinfo ()
{
    _progname="$1"        # passed to rpcinfo (looked up in /etc/rpc)
    _versions="$2"        # optional, space separated, not passed if empty/unset
    _families="${3:-tcp}" # optional, space separated, default is "tcp"

    for _family in $_families ; do
	if [ -n "$_versions" ] ; then
	    for _version in $_versions ; do
		ctdb_check_rpc "$_progname" "$_version" "$_family" || return $?
	    done
	else
	    ctdb_check_rpc "$_progname" "" "$_family" || return $?
	fi
    done
}

##################################################################
# use statd-callout to update NFS lock info
##################################################################
nfs_update_lock_info ()
{
    if [ -x "$CTDB_BASE/statd-callout" ] ; then
	"$CTDB_BASE/statd-callout" update
    fi
}

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

nfs_callout_init "$service_state_dir"

ctdb_start_stop_service

is_ctdb_managed_service || exit 0

case "$1" in
startup)
	nfs_callout "$@"
	;;

shutdown)
	 nfs_callout "$@"
	;;

takeip)
	nfs_callout "$@"
	ctdb_service_set_reconfigure
	;;

releaseip)
	nfs_callout "$@"
	ctdb_service_set_reconfigure
	;;

ipreallocated)
	if ctdb_service_needs_reconfigure ; then
		ctdb_service_reconfigure
	fi
	;;

monitor)
	nfs_callout "monitor-pre" || exit $?

	# Check that directories for shares actually exist
	if [ "$CTDB_NFS_SKIP_SHARE_CHECK" != "yes" ] ; then
	    nfs_callout "monitor-list-shares" | ctdb_check_directories || \
		exit $?
	fi

	update_tickles 2049
	nfs_update_lock_info

	nfs_check_services

	nfs_callout "monitor-post" || exit $?
       	;;
esac

exit 0