#!/bin/bash

if [ $# -lt 2 ]; then
	echo "Bad call to $0." >&2
	echo "Expected: $0 images <source> [username] [password]" >&2
	exit 1
fi

WHAT="$1"
SOURCE="$2"
USERNAME="$3"
PASSWORD="$4"

# Currently WHAT can only be images (the central store for all images),
# but maybe there will be other storage types in the future.
case "$WHAT" in
images)
	DEST="/srv/openslx/nfs"
	;;
*)
	echo "Invalid/Unknown mount type: '$WHAT'." >&2
	exit 1
	;;
esac

FLAG="${DEST}/.notmounted"
SUBDIR="${DEST}/bwlehrpool_store"

# Sanity checks: Destination exists?
if [ ! -d "$DEST" ]; then
	mkdir -p "$DEST"
	chown root:images "$DEST"
	chmod 0775 "$DEST"
fi

# Still a no?
if [ ! -d "$DEST" ]; then
	echo "Mount point '$DEST' does not exist and could not be created!" >&2
	echo "This should not happen and means this server is severely messed up. :(" >&2
	exit 1
fi

# Already mounted?
if awk '{print $2}' "/proc/mounts" | grep -q "^${DEST}\$"; then
	echo "Trying to unmount '$DEST'..."
	umount -v "$DEST"
	RET=$?
	if [ "$RET" -ne "0" ]; then
		echo "Cannot unmount '$DEST'!" >&2
		echo "Storage might be in use (running VM upload etc.)" >&2
		echo "Try stopping DMSD first" >&2
		exit "$RET"
	fi
fi

# Unmount and not requested to mount (local mode)
if [[ "${SOURCE}" == "null" ]]; then
	rm -f "${FLAG}"
	exit 0
fi

touch "${FLAG}"

# Mount!

if grep -E -q '^[^/].+:.+' <<<$SOURCE; then
	# seems to be NFS
	for opt in vers=4 vers=3; do
		mount -v -t nfs -o rw,noatime,noexec,nodev,async,nolock,$opt,fg,ac,retry=1,timeo=150,sec=sys "$SOURCE" "$DEST"
		RET=$?
		[ "$RET" -eq "0" ] && break
	done
elif grep -E -q '^//' <<<$SOURCE; then
	# seems to be SMB
	export USER="$USERNAME"
	export PASSWD="$PASSWORD"
	for sec in ntlmv2 ntlm; do
		echo " * Trying ${sec}..."
		mount -v -t cifs -o rw,uid=0,gid=12345,forceuid,forcegid,nounix,file_mode=0664,dir_mode=0775,sec=$sec "$SOURCE" "$DEST"
		RET=$?
		if [ "$RET" -eq "0" ]; then
			echo " * Success!"
			break
		fi
	done
	unset USER PASSWD
else
	echo "Unknown mount type: $SOURCE"
	exit 1
fi

echo "----------------------------------"

if [ "$RET" == "0" ]; then
	rm -f "${FLAG}"
	if [ -e "${FLAG}" ]; then
		echo "Error: File '.notmounted' exists on remote storage. Delete first!" >&2
		umount -v "$DEST"
		exit 5
	fi
	chgrp images "${DEST}" 2>/dev/null
	mkdir -p "${SUBDIR}"
	if [ ! -d "${SUBDIR}" ]; then
		echo "Error: Could not create $(basename "$SUBDIR")! Storage not writable!" >&2
		umount -v "$DEST"
		exit 6
	fi
	chgrp -R images "${SUBDIR}" 2>/dev/null &
	chmod -R ug+rwX "${SUBDIR}" 2>/dev/null &
	TEST="${SUBDIR}/.deleteme-$RANDOM-$RANDOM"
	sudo -n -u dmsd touch "$TEST"
	RET=$?
	if [ -e "$TEST" ]; then
		sudo -n -u dmsd rm -f -- "$TEST"
	else
		[ "$RET" = "0" ] && RET=127
		echo "Error: Mounted share is not writable, aborting." >&2
		umount -v "$DEST"
	fi
fi

if [ "$RET" = "0" ]; then
	echo "----------------------------------"
	echo "-- Share mounted successfully!  --"
	echo "----------------------------------"
fi

exit $RET