#!/bin/sh
#
# Pawel Jakub Dawidek <pjd@FreeBSD.org>
#
# This script is supposed to remount file systems with org.freebsd:owner
# property set as regular user from the property. This way file system owner
# will be able to perform further operations on the file system.
#

zfs list -H -t filesystem -o name,canmount,mountpoint,org.freebsd:owner | while read dataset canmount mountpoint owner; do
	# Skip datasets that are not suppose to be mounted.
	[ "${canmount}" != "on" ] && continue
	# Skip datasets with non-path mountpoints.
	[ "${mountpoint}" = "${mountpoint#/}" ] && continue
	# Skip datasets without org.freebsd:owner property.
	[ "${owner}" = "-" ] && continue

	# Get owner's UID needed for chown.
	# This way we also check if the owner from the property is an existing system user.
	uid=`id -u ${owner} 2>/dev/null`
	if [ $? -ne 0 ]; then
		echo "Invalid org.freebsd:owner property set for ${dataset}, skipping." >/dev/stderr
		continue
	fi

	# Skip if already mounted by the given user.
	mount -t zfs | egrep -q '^'${dataset}' on '${mountpoint}' \(zfs, .*, mounted by '${owner}'\)$'
	[ $? -eq 0 ] && continue

	# Owner's gid for chown.
	gid=`id -g ${owner}`
	[ $? -ne 0 ] && continue	# Should never fail.

	# Unmount file system if it is actually mounted.
	if [ "`zfs get -H -o value mounted ${dataset}`" = "yes" ]; then
		out=`zfs umount ${dataset} 2>&1`
		if [ $? -ne 0 ]; then
			echo "zfs umount ${dataset} failed (${out}), skipping." >/dev/stderr
			continue
		fi
	fi

	# Create mountpoint directory if it doesn't exist.
	if [ ! -d ${mountpoint} ]; then
		out=`mkdir ${mountpoint} 2>&1`
		if [ $? -ne 0 ]; then
			echo "mkdir ${mountpoint} failed (${out}), skipping." >/dev/stderr
			continue
		fi
	fi

	# Set mountpoint directory owner to the file system owner.
	out=`chown ${uid}:${gid} ${mountpoint} 2>&1`
	if [ $? -ne 0 ]; then
		echo "chown ${uid}:${gid} ${mountpoint} failed (${out}), skipping." >/dev/stderr
		continue
	fi

	# Mount the file system with owner's credentials.
	out=`su -m ${owner} -c "zfs mount ${dataset}" 2>&1`
	if [ $? -ne 0 ]; then
		echo "zfs mount ${dataset} failed (${out}), skipping." >/dev/stderr
		continue
	fi
done

zfs share -a