#!/bin/sh
# exportfs
#
# Description: Manages nfs exported file system.
#
#   (c) 2010 Ben Timby, Florian Haas, Dejan Muhamedagic,
#            and Linux-HA contributors
#
# License: GNU General Public License v2 (GPLv2) and later

#######################################################################
# Initialization:
: ${OCF_FUNCTIONS_DIR=${OCF_ROOT}/lib/heartbeat}
. ${OCF_FUNCTIONS_DIR}/ocf-shellfuncs

# Defaults
OCF_RESKEY_unlock_on_stop_default=1
OCF_RESKEY_wait_for_leasetime_on_stop_default=0
OCF_RESKEY_rmtab_backup_default=".rmtab"

: ${OCF_RESKEY_unlock_on_stop=${OCF_RESKEY_unlock_on_stop_default}}
: ${OCF_RESKEY_wait_for_leasetime_on_stop=${OCF_RESKEY_wait_for_leasetime_on_stop_default}}
: ${OCF_RESKEY_rmtab_backup=${OCF_RESKEY_rmtab_backup_default}}
#######################################################################

exportfs_meta_data() {
	cat <<END
<?xml version="1.0"?>
<!DOCTYPE resource-agent SYSTEM "ra-api-1.dtd">
<resource-agent name="exportfs">
<version>1.0</version>

<longdesc lang="en">
Exportfs uses the exportfs command to add/remove nfs exports.
It does NOT manage the nfs server daemon.
It depends on Linux specific NFS implementation details,
so is considered not portable to other platforms yet.
</longdesc>

<shortdesc lang="en">
Manages NFS exports
</shortdesc>

<parameters>

<parameter name="clientspec" unique="0" required="1">
<longdesc lang="en">
The client specification allowing remote machines to mount the directory
(or directories) over NFS.
</longdesc>
<shortdesc lang="en">
Client ACL.
</shortdesc>
<content type="string" />
</parameter>

<parameter name="options" unique="0" required="0">
<longdesc lang="en">
The options to pass to exportfs for the exported directory
or directories.
</longdesc>
<shortdesc lang="en">
Export options.
</shortdesc>
<content type="string" />
</parameter>

<parameter name="directory" unique="0" required="1">
<longdesc lang="en">
The directory or directories to be exported using NFS. Multiple
directories are separated by white space.
</longdesc>
<shortdesc lang="en">
The directory or directories to export.
</shortdesc>
<content type="string" />
</parameter>

<parameter name="fsid" unique="1" required="1">
<longdesc lang="en">
The fsid option to pass to exportfs. This can be a unique positive
integer, a UUID (assuredly sans comma characters), or the special string
"root" which is functionally identical to numeric fsid of 0.
If multiple directories are being exported, then they are
assigned ids sequentially starting with this fsid (fsid, fsid+1,
fsid+2, ...). Obviously, in that case the fsid must be an
integer.
0 (root) identifies the export as the root of an NFSv4
pseudofilesystem -- avoid this setting unless you understand its
special status.
This value will override any fsid provided via the options parameter.
</longdesc>
<shortdesc lang="en">
Unique fsid within cluster or starting fsid for multiple exports.
</shortdesc>
<content type="string" />
</parameter>

<parameter name="unlock_on_stop">
<longdesc lang="en">
Relinquish NFS locks associated with this filesystem when the resource
stops. Enabling this parameter is highly recommended unless the path exported
by this ${__SCRIPT_NAME} resource is also exported by a different resource.

Note: Unlocking is only possible on Linux systems where
/proc/fs/nfsd/unlock_filesystem exists and is writable. If your system does
not fulfill this requirement (on account of having an nonrecent kernel,
for example), you may set this parameter to 0 to silence the associated
warning.
</longdesc>
<shortdesc lang="en">
Unlock filesystem on stop?
</shortdesc>
<content type="boolean" default="${OCF_RESKEY_unlock_on_stop_default}" />
</parameter>

<parameter name="wait_for_leasetime_on_stop">
<longdesc lang="en">
When stopping (unexporting), wait out the NFSv4 lease time.
Only after all leases have expired does the NFS kernel server
relinquish all server-side handles on the exported filesystem.
If this ${__SCRIPT_NAME} resource manages an export that resides
on a mount point designed to fail over along with the NFS export
itself, then enabling this parameter will ensure such failover
is working properly. Note that when this parameter is set, your
stop timeout MUST accommodate for the wait period. This parameter
is safe to disable if none of your NFS clients are using NFS
version 4 or later.
</longdesc>
<shortdesc lang="en">
Ride out the NFSv4 lease time on resource stop?
</shortdesc>
<content type="boolean" default="${OCF_RESKEY_wait_for_leasetime_on_stop_default}" />
</parameter>

<parameter name="rmtab_backup">
<longdesc lang="en">
Back up those entries from the NFS rmtab that apply to the exported
directory, to the specified backup file. The filename is interpreted
as relative to the exported directory. This backup is required if
clients are connecting to the export via NFSv3 over TCP. Note that a
configured monitor operation is required for this functionality.

To disable rmtab backups, set this parameter to the special
string "none".
</longdesc>
<shortdesc lang="en">
Location of the rmtab backup, relative to directory.
</shortdesc>
<content type="string" default="${OCF_RESKEY_rmtab_backup_default}" />
</parameter>
</parameters>

<actions>
<action name="start"   timeout="40" />
<action name="stop"    timeout="120" />
<action name="monitor" depth="0"  timeout="20" interval="10" />
<action name="meta-data"  timeout="5" />
<action name="validate-all"  timeout="30" />
</actions>
</resource-agent>
END

return $OCF_SUCCESS
}

exportfs_methods() {
  cat <<-EOF
	start
	stop
	status
	monitor
	validate-all
	methods
	meta-data
	usage
	EOF
}

reset_fsid() {
	CURRENT_FSID=$OCF_RESKEY_fsid
}
bump_fsid() {
	CURRENT_FSID=$((CURRENT_FSID+1))
}
get_fsid() {
	echo $CURRENT_FSID
}

# run a function on all directories
forall() {
	local func=$1
	shift 1
	local fast_exit=""
	local dir rc=0
	if [ "$2" = fast_exit ]; then
		fast_exit=1
		shift 1
	fi
	reset_fsid
	for dir in $OCF_RESKEY_directory; do
		$func $dir "$@"
		rc=$(($rc | $?))
		[ $NUMDIRS -gt 1 ] && bump_fsid
		[ "$fast_exit" ] && continue
		[ $rc -ne 0 ] && return $rc
	done
	return $rc
}

backup_rmtab() {
	local dir=$1
	local rmtab_backup
	rmtab_backup="$dir/${OCF_RESKEY_rmtab_backup}"
	grep ":$dir:" /var/lib/nfs/rmtab > ${rmtab_backup}
}

restore_rmtab() {
	local dir=$1
	local rmtab_backup
	rmtab_backup="$dir/${OCF_RESKEY_rmtab_backup}"
	if [ -r ${rmtab_backup} ]; then
		local tmpf=`mktemp`
		sort -u ${rmtab_backup} /var/lib/nfs/rmtab > $tmpf &&
		install -o root -m 644 $tmpf /var/lib/nfs/rmtab
		rm -f $tmpf
		ocf_log debug "Restored `wc -l ${rmtab_backup}` rmtab entries from ${rmtab_backup}."
	else
		ocf_log warn "rmtab backup ${rmtab_backup} not found or not readable."
	fi
}

exportfs_usage() {
	cat <<END
		usage: $0 {start|stop|monitor|status|validate-all|meta-data}
END
}

format_exports() {
	# exportfs output wraps lines for long export directory names.
	# We unwrap here with sed.
	# We then do a literal match on the full line (grep -x -F)
	exportfs |
		sed -e '$! N; s/\n[[:space:]]\+/ /; t; s/[[:space:]]\+\([^[:space:]]\+\)\(\n\|$\)/ \1\2/g; P;D;'
}
is_exported() {
	local dir=$1
	local spec=$2
	local rc
	format_exports | grep -q -x -F "$dir $spec"
	rc=$?
	if [ $rc -ne 0 -a "$spec" = "*" ]; then
		# on some platforms, exportfs may print
		# "<world>" instead of "*"
		format_exports | grep -q -x -F "$dir <world>"
		rc=$?
	fi
	# log something only for monitors
	if [ $rc -ne 0 -a "$__OCF_ACTION" = "monitor" ]; then
		local sev="info"
		ocf_is_probe || sev="err"
		ocf_log $sev "$dir not exported to $spec (stopped)."
	fi
	return $rc
}

exportfs_monitor ()
{
	local spec

	if ! ha_pseudo_resource "${OCF_RESOURCE_INSTANCE}" monitor; then
		return $OCF_NOT_RUNNING
	fi

	spec="$(echo "$OCF_RESKEY_clientspec" | sed -e 's/^\[*//' -e 's/\]*$//')"
	if forall is_exported "$spec"; then
		if [ ${OCF_RESKEY_rmtab_backup} != "none" ]; then
			forall backup_rmtab
		fi
		return $OCF_SUCCESS
	else
		return $OCF_NOT_RUNNING
	fi
}

export_one() {
	local dir=$1
	local opts sep
	sep=""
	if [ -n "$OCF_RESKEY_options" ]; then
		opts="$OCF_RESKEY_options"
		sep=","
	fi
	if echo "$opts" | grep fsid >/dev/null; then
		#replace fsid in options list
		opts=`echo "$opts" | sed "s,fsid=[^,]*,fsid=$(get_fsid),g"`
	else
		#tack the fsid option onto our options list.
		opts="${opts}${sep}fsid=$(get_fsid)"
	fi
	opts="-o $opts"

	# if any of directories fails to export we can exit
	# immediately
	ocf_run exportfs -v $opts "${OCF_RESKEY_clientspec}:$dir"
	if [ $? -ne 0 ]; then
		ocf_exit_reason "exportfs failed - exportfs -v $opts ${OCF_RESKEY_clientspec}:$dir"
		exit $OCF_ERR_GENERIC
	fi

	ocf_log info "directory $dir exported"
	return $OCF_SUCCESS
}
exportfs_start ()
{
	if exportfs_monitor; then
		ocf_log debug "already exported"
		return $OCF_SUCCESS
	fi
	ocf_log info "Exporting file system(s) ..."

	ha_pseudo_resource "${OCF_RESOURCE_INSTANCE}" start
	forall export_one

	# Restore the rmtab to ensure smooth NFS-over-TCP failover
	if [ ${OCF_RESKEY_rmtab_backup} != "none" ]; then
		forall restore_rmtab
	fi
}

unlock_fs() {
	local dir=$1
	local unlockfile
	unlockfile=/proc/fs/nfsd/unlock_filesystem
	if [ -w ${unlockfile} ]; then
		echo "$dir" > ${unlockfile}
		ocf_log info "Unlocked NFS export $dir"
	else
		ocf_log warn "Unable to unlock NFS export $dir, ${unlockfile} not found or not writable"
	fi
}
wait_for_leasetime() {
	local leasetimefile
	local sleeptime
	leasetimefile=/proc/fs/nfsd/nfsv4leasetime
	if [ -r ${leasetimefile} ]; then
		sleeptime=$((`cat ${leasetimefile}`+2))
		ocf_log info "Sleeping ${sleeptime} seconds to accommodate for NFSv4 lease expiry"
		sleep ${sleeptime}s
	else
		ocf_log warn "Unable to read NFSv4 lease time from ${leasetimefile}, file not found or not readable"
	fi
}
cleanup_export_cache() {
	# see if the cache is blocking unexport
	local contentfile=/proc/net/rpc/nfsd.export/content
	local fsid_re
	local i=1
	fsid_re="fsid=(echo `forall get_fsid`|sed 's/ /|/g'),"
	while :; do
		grep -E -q "$fsid_re" $contentfile ||
			break
		ocf_log info "Cleanup export cache ... (try $i)"
		ocf_run exportfs -f
		sleep 0.5
		i=$((i + 1))
	done
}
unexport_one() {
	local dir=$1
	ocf_run exportfs -v -u ${OCF_RESKEY_clientspec}:$dir
}
exportfs_stop ()
{
	local rc

	exportfs_monitor
	if [ $? -eq $OCF_NOT_RUNNING ]; then
		ocf_log debug "not exported"
		return $OCF_SUCCESS
	fi

	ocf_log info "Un-exporting file system ..."

	# Backup the rmtab to ensure smooth NFS-over-TCP failover
	if [ ${OCF_RESKEY_rmtab_backup} != "none" ]; then
		forall backup_rmtab
	fi

	forall unexport_one
	rc=$?

	if ocf_is_true ${OCF_RESKEY_unlock_on_stop}; then
		forall unlock_fs
	fi

	if ocf_is_true ${OCF_RESKEY_wait_for_leasetime_on_stop}; then
		wait_for_leasetime
	fi

	if [ $rc -eq 0 ]; then
		cleanup_export_cache
		ha_pseudo_resource "${OCF_RESOURCE_INSTANCE}" stop

		ocf_log info "Un-exported file system(s)"
		return $OCF_SUCCESS
	else
		ocf_exit_reason "Failed to un-export file system(s)"
		return $OCF_ERR_GENERIC
	fi
}

testdir() {
	if [ ! -d $1 ]; then
		ocf_is_probe ||
			ocf_log err "$1 does not exist or is not a directory"
		return 1
	fi
	return 0
}
exportfs_validate_all ()
{
	if echo "$OCF_RESKEY_fsid" | grep -q -F ','; then
		ocf_exit_reason "$OCF_RESKEY_fsid cannot contain a comma"
		return $OCF_ERR_CONFIGURED
	fi
	if [ $NUMDIRS -gt 1 ] &&
			! ocf_is_decimal "$OCF_RESKEY_fsid"; then
		ocf_exit_reason "use integer fsid when exporting multiple directories"
		return $OCF_ERR_CONFIGURED
	fi
	if ! forall testdir; then
		return $OCF_ERR_INSTALLED
	fi
}

# If someone puts a trailing slash at the end of the export directory,
# this agent is going to fail in some unexpected ways due to how
# export strings are matched.  The simplest solution here is to strip off
# a trailing '/' in the directory before processing anything.
newdir=$(echo "$OCF_RESKEY_directory" | sed -n -e 's/^\(.*\)\/$/\1/p')
if [ -n "$newdir" ]; then
	OCF_RESKEY_directory=$newdir
fi

NUMDIRS=`echo "$OCF_RESKEY_directory" | wc -w`
OCF_REQUIRED_PARAMS="directory fsid clientspec"
OCF_REQUIRED_BINARIES="exportfs"
ocf_rarun $*
