#!/bin/sh
#
# vm-mount.sh - mount Windows NTFS partitions residing on LVM volumes.
#
# Copyright (C) 2024 Heiko Sieger
# https://heiko-sieger.info
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.

# Usage: sudo vm-mount.sh vm_volume
#
# where "vm_volume" is the name of the volume as found in
# "/dev/mapper/", for example "volume_group-windows_lv"
#
# Dependencies
# ============
#
# The script requires the following:
#	'kpartx' from package 'multipath-tools'
#	'virsh' from package 'libvirt'
#	'notify-send' from package 'libnotify'
#

vm_volume="$1"
user=$(logname)
rc=0

export $(dbus-launch)

mount_vol ()
{
	mkdir -p "$mount_path"
	rw_mode="$1"
	case $rw_mode in
		rw)
			notify-send "$vm_name is shut off" "Mounting volume $vm_volume in read-write mode." -i dialog-information
			;;
		ro)
			notify-send "$vm_name is running" "Mounting volume $vm_volume in read-only mode." -i dialog-information
			;;
		*)
			exit 1
			;;
	esac
#	mount -t ntfs3 -o "$rw_mode",iocharset=utf8,dmask=027,fmask=137,uid=$(id -u $user),gid=$(id -g $user),discard "$mount_dev" "$mount_path"
	mount -t ntfs-3g -o "$rw_mode",nls=utf8,umask=000,dmask=027,fmask=137,uid=$(id -u $user),gid=$(id -g $user),windows_names "$mount_dev" "$mount_path"
	rc=$?
}

umount_vol ()
{
	# Loop until vm_mount can be unmounted
	while fuser -sMm "$mount_path"; do
		notify-send -wt 10000 "Cannot unmount $vm_volume - device is busy" "Close all files in $vm_volume and click message to try again." -i dialog-warning
	done
	
	umount "$mount_path" && notify-send "Info" "Unmounted volume $vm_volume." -i dialog-information
	sleep 2
	rmdir "$mount_path" || notify-send -t 0 "Error" "Could not remove directory $mount_path" -i dialog-error
	kpartx -d "$vm_path" || notify-send -t 0 "Error" "Could not unmap $vm_volume" -i dialog-error
}

# See that the required packages are installed
if ! type notify-send 2>2; then echo "Error: notify-send from package libnotify is not installed. Abort."; exit 2; fi

if ! type kpartx 2>2; then notify-send -t 0 "Error" "kpartx from package <b>multipath-tools</b> is not installed. Abort." -i dialog-error; exit 2; fi

if ! type virsh 2>2; then notify-send -t 0 "Error" "virsh from package <b>libvirt</b> is not installed. Abort." -i dialog-error; exit 2; fi

# Run as root
if [ $UID -ne 0 ]; then
	notify-send -t 0 "Error" "Script must be run as '<b>root</b>' (sudo). Abort." -i dialog-error
	exit 3
fi

if [ -z "$vm_volume" ]; then
	notify-send -t 0 "Usage error" "Usage: <i>sudo ./vm-mount.sh volume_group-logical_volume</i>" -i dialog-error
	exit 4
fi

vm_path="/dev/mapper/${vm_volume}"
mount_path="/mnt/$vm_volume"

# Check input. If vm_path doesn't exist, exit
if [ ! -b "$vm_path" ]; then
	notify-send -t 0 "Error" "Volume $vm_volume does not exist. Abort." -i dialog-error
	exit 5
fi

# Determine vm_name associated with vm_volume
vm_dev="$(echo $vm_volume | sed 's|-|/|')"
found="no"
domains="$(virsh list --all --name)"

for vm_name in $domains; do
	if [[ "$(virsh -q domblklist $vm_name | awk '{ print $NF }' | grep -x /dev/$vm_dev)" ]]; then
		found="yes"; break
	fi
done

if [[ $found != "yes" ]]; then
	notify-send -t 0 "Error" "$vm_volume not associated with any VM. Abort." -i dialog-error
	exit 6
fi

# See if the volume is already mounted and if it is of type "fuseblk" or ntfs3.
if cat /proc/mounts | grep -qE "${mount_path} (fuseblk|ntfs3)"; then
	umount_vol
else
	# Create a mapper device for each partition in the vm_volume and
	# assign the largest partition to $dev
	kpartx -av "$vm_path"
	if [ -b "${vm_path}p1" ]; then
		dev="$(lsblk -no NAME,SIZE ${vm_path}p? | sort -h -k 2 | awk '{ print $(NF-1) }')"
		dev="$(echo $dev | awk '{ print $NF }')"
	else
		if [ -b "${vm_path}1" ]; then
			dev="$(lsblk -no NAME,SIZE ${vm_path}? | sort -h -k 2 | awk '{ print $(NF-1) }')"
			dev="$(echo $dev | awk '{ print $NF }')"
		else
			dev="$vm_volume"
		fi
	fi

	mount_dev="/dev/mapper/$dev"

	# Make sure mount_dev is of type ntfs
	if [[ "$(lsblk -no FSTYPE ${mount_dev})" != "ntfs" ]]; then 
		notify-send -t 0 "Mount error" "$vm_volume is not an NTFS file system! Abort." -i dialog-error
		kpartx -d "$vm_path"
		exit 7
	fi
	
	# Mount rw if VM is shutoff, else mount ro
	if virsh list --name --state-shutoff | grep -xq $vm_name; then
		mount_vol rw
	else
		mount_vol ro
	fi
	
	if [ $rc = 0 ] ; then
		# Open file browser as user 1000
		# sudo -u \#1000 -H nohup xdg-open "$mount_path" &
		sudo -u "$user" -H nohup xdg-open "$mount_path" &
		exit 0
	else
		notify-send -t 0 "Mount error" "Could not mount volume $vm_volume !" -i dialog-error
		# clean up
		kpartx -d "$vm_path"
		rmdir "$mount_path"
		exit 8
	fi
fi

#EOF

# exit codes:
# exit 1 - unknown error
# exit 2 - dependencies not met / missing package
# exit 3 - script called without 'sudo' root privileges
# exit 4 - usage error - missing vm_volume parameter
# exit 5 - vm_volume not found
# exit 6 - vm_volume not associated with a VM
# exit 7 - vm_volume is not an NTFS file system
# exit 8 - could not mount vm_volume