Qubes redirect mouse input to VM

README.md

How it works:

This script will detect the active VM based on the currently focused window and redirect mouse events from DOM0 to the VM until the script is ran again.

This works for games or anything that uses your mouse.

This is basically doing the reverse of how sys-usb makes your mouse available to your entire system.

Based on:

• QubesOS/qubes-issues#4986
• qubes-app-linux-input-proxy
• qubes-i3-sensible-terminal (VM detection code)

Setup:

• Install qubes-input-proxy-receiver in the VMs you want to use this in.

  Ideally, you'll install qubes-input-proxy-receiver in a template VM and restart your qubes.

  Fedora based qubes:

  sudo dnf install qubes-input-proxy-receiver

• Copy the script below to DOM0 and make it executable

  In a networked VM:

  curl -o /home/user/toggle-mouse.sh https://gist.githubusercontent.com/e9x/f505cf11d42f9470570c9de0b61e15e9/raw/b8ce3f1ca4a2fff1c358d14b4811789a58d0a4eb/toggle-mouse.sh

  In DOM0:

  qvm-run --pass-io your-vm "cat /home/user/toggle-mouse.sh" > /home/user/toggle-mouse.sh
  chmod +x /home/user/toggle-mouse.sh

  Make sure to review the script and make sure it's safe.

  cat /home/user/toggle-mouse.sh

• Configure the script

  Identify your mouse event ID in /dev/input/by-id/

  Make sure your mouse is connected directly to DOM0 and is not in a USB VM

  In DOM0:

  ls /dev/input/by-id/*-event-mouse

  Modify the script to use this mouse

  nano /home/user/toggle-mouse.sh

  Modify this line accordingly.

  local mouse=/dev/input/by-id/usb-Logitech_G203_LIGHTSYNC_Gaming_Mouse-event-mouse

• Add a keybind to run this script when a key is pressed

  Qubes by default comes with XFCE which you can configure keyboard shortcuts on.

  In DOM0:

  xfce4-keyboard-settings

  Go to "Application Shortcuts", click on "Add"

  Command: /home/user/toggle-mouse.sh

  Press "Ok", then press the key you want to bind it to.

Usage:

You should now be able to open an application that you want to redirect your mouse to, then press the key you binded the script to, then all your mouse events should go directly to the VM instead of DOM0.

Your cursor icon won't be visible, but this could be fixed in the future by spawning swcursor inside the VM while mouse events are being redirected to simulate the cursor icon.

Security:

TODO

toggle-mouse.sh

#!/bin/bash

get_id() {
    local id=$(xprop -root _NET_ACTIVE_WINDOW)
    # had to fix this, used to be #{id##* }
    local id=${id#*window id # }
    echo ${id%%, *} # extract id
}

get_vm() {
    local id=$(get_id)
    local abc=$(xprop -id $id)
    local vm=$(xprop -id $id | grep '_QUBES_VMNAME(STRING)')
    local vm=${vm#*\"} # extract vmname
    echo ${vm%\"*} # extract vmname
}

main() {
    # configure with your mouse event device here
    local mouse=/dev/input/by-id/usb-Logitech_G203_LIGHTSYNC_Gaming_Mouse-event-mouse

    # this script can be reworked to get the input events from a USB VM and pass them to another VM

    # lockfile path
    local tmp_file=/home/user/mouse-vm.tmp

    # get the active VM
    local vm=$(get_vm)
    #notify-send "active vm: $vm"

    # attempt to detach the mouse if we detect that iwas previously attached
    if [ -f "$tmp_file" ]; then
        #local attached_vm=$(cat $tmp_file)
        #TODO:
        #kill -9 $attached_vm
        sudo killall input-proxy-sender
        rm -- "$tmp_file"
        #notify-send "detached mouse from vm, killed $attached_vm"
    else
        # attach the mouse and save the state to $tmp_file
        if [[ -n "$vm" ]]; then
            #notify-send "attaching mouse to $vm"
            sudo qvm-run -u root --pass-io --localcmd="input-proxy-sender $mouse" $vm "input-proxy-receiver --mouse"&
            # TODO: find a normal way to get the pid of the input-proxy-sender that we just spawned
            # wait for the qvm-run command to spawn input-proxy-sender then write the pid to a file
            #sleep 1; echo "$(pidof input-proxy-sender)" > $tmp_file
            # alternatively, we can just create the $tmp_file without any contents and kill every process with the name input-proxy-senedr
            touch $tmp_file
        fi
    fi
}

main

line 43 qvm-run ... for me fails with: open: Permission denied
I assigned my only mouse to mouse var 🫤
I have no USB qube

As a side note, you should always use set -euo pipefail in Bash scripts to catch errors and stop execution of the rest of the script.

I have no USB qube

This script uses the USB mouse from DOM0, so this is correct.

open: Permission denied

I haven't encountered this on my system. I think the documentation from input-proxy-sender is relevant:

You need to have access to the device file, which most likely means that you need to start input-proxy-sender as root, or you need some udev rule to alter file permissions.

https://github.com/QubesOS/qubes-app-linux-input-proxy?tab=readme-ov-file#input-proxy-sender

I'm not familiar with udev rules, but I think running input-proxy-sender with sudo should fix this.

qvm-run -u root --pass-io --localcmd="sudo input-proxy-sender $mouse" $vm "input-proxy-receiver --mouse"&

@mooreye Are you able to try this?

@e9x
Thanks, it works when I added sudo to input-proxy-sender.
It was also necessary for me to add sudo to killall. Otherwise, it wouldn't detach the mouse.

Good to hear it worked! I've updated the script to use sudo for starting the input sender and detaching the mouse.