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MQTT usb attach/detach script to make some sort of build-in kvm

Nixx
in Programming

Featured Replies

Ok, so maybe it's just me but i didn't found anything to do that so i try to build it myself.

 

Basically, it will make the unraid server to suscribe to /unraid/attach-device-usb and you can send message like :

{"domain": "Work", "vendorid": "320f", "pid": "5041", "dismount": true}
Domain is the vm, vendorId/productId, the vid/pid of your usb device (you can use lsusb to list), dismount:true means it will detach to existing vm before try to attach it.

 

 

To make it work, you need this plugin : 

 and a mqtt server.

 

 

Here my script :  

#!/bin/bash

# Load MQTT credentials from the configuration file
source /boot/config/mqttcredentials

# Check that all necessary variables are defined
if [[ -z "$MQTT_HOST" || -z "$MQTT_PORT" || -z "$MQTT_USER" || -z "$MQTT_PASSWORD" || -z "$MQTT_CLIENT_ID" ]]; then
  echo "Error: MQTT credentials are incomplete."
  exit 1
fi

# Function to handle messages from the 'unraid/switchkeyboard' topic
handle_switchkeyboard() {
  # Subscribe to the 'unraid/attach-device-usb' topic and print received messages with 'echo'
  mosquitto_sub -h $MQTT_HOST -p $MQTT_PORT -u $MQTT_USER -P $MQTT_PASSWORD -t "unraid/attach-device-usb" | while read -r message; do
    echo "Message received on 'unraid/attach-device-usb' : $message"

    # Parse the received JSON message
    domain=$(echo "$message" | jq -r '.domain')
    vendorid=$(echo "$message" | jq -r '.vendorid')
    pid=$(echo "$message" | jq -r '.pid')
    dismount=$(echo "$message" | jq -r '.dismount')

    # Check if the necessary information is present
    if [[ -z "$domain" || -z "$vendorid" || -z "$pid" ]]; then
      echo "Error: Missing information in MQTT message."
      continue
    fi

    # Create a temporary XML file for the device
    temp_file=$(mktemp /tmp/device_XXXX.xml)
    cat <<EOF > "$temp_file"
<hostdev mode='subsystem' type='usb'>
  <source>
    <vendor id='0x$vendorid'/>
    <product id='0x$pid'/>
  </source>
</hostdev>
EOF

    echo "Temporary file created: $temp_file"

    # Check if dismount is set to true and process accordingly
    if [[ "$dismount" == "true" ]]; then
      # Regex to check if a device with the given vendorid and pid is already attached to a domain
      device_attached_to_domain=""
      for domain_name in $(virsh list --all --name); do
        if [[ -n "$domain_name" ]]; then
          # Use a regex to search for vendorid and pid in the XML configuration of the domain
          device_attached=$(virsh dumpxml "$domain_name" | tr -d '\0' | \
            grep -Pzo "(?s)<hostdev.*<vendor id='0x$vendorid'.*<product id='0x$pid'")

          # If the device is found in the XML of this domain, mark it
          if [[ -n "$device_attached" ]]; then
            device_attached_to_domain="$domain_name"
            break
          fi
        fi
      done

      # If the device is attached to a different domain, detach it
      if [[ -n "$device_attached_to_domain" && "$device_attached_to_domain" != "$domain" ]]; then
        echo "Device is already attached to $device_attached_to_domain. Detaching it from there."
        virsh detach-device "$device_attached_to_domain" "$temp_file"
        # Wait for 2 seconds before attaching the device to the target domain
        sleep 2
      fi
    else
      echo "Dismount is set to false or not provided. Skipping dismount operation."
    fi

    # Check if the device is currently attached to the target domain
    device_in_use=$(virsh dumpxml "$domain" | tr -d '\0' | \
      grep -Pzo "(?s)<hostdev.*<vendor id='0x$vendorid'.*<product id='0x$pid'")

    if [[ -n "$device_in_use" ]]; then
      echo "Error: Device is already in use by domain '$domain'."
    else
      # Attach the device to the destination domain
      echo "Attaching device to virtual machine: $domain"
      virsh attach-device "$domain" "$temp_file"
    fi

    # Remove the temporary file
    rm -f "$temp_file"
  done
}

# Launch the function to handle the switchkeyboard topic
handle_switchkeyboard

 

As a side note my windows vm i use a autohotscript like that, so i have key binding on my keyboard to switch beetween computers.
I use dismount:false on the initial code, so it will only attach if it's not currently attached on an running vm. (and i put it into startup with autologin activated)
  

commande := """C:\Program Files\mosquitto\mosquitto_pub.exe"" -h 192.168.1.25 -p 1883 -u xxxx -P xxxx -t ""unraid/attach-device-usb"" -m ""{\""domain\"": \""Work\"", \""vendorid\"": \""320f\"", \""pid\"": \""5041\"", \""dismount\"": false}"""
Run, % commande, , Hide
commande := """C:\Program Files\mosquitto\mosquitto_pub.exe"" -h 192.168.1.25 -p 1883 -u xxxx -P xxxx -t ""unraid/attach-device-usb"" -m ""{\""domain\"": \""Work\"", \""vendorid\"": \""1532\"", \""pid\"": \""0067\"", \""dismount\"": false}"""
Run, % commande, , Hide
F21::
	Run, "C:\Program Files\mosquitto\mosquitto_pub.exe" -h 192.168.1.25 -p 1883 -u xxxx -P xxxx -t "dpswitch/bouton" -m "ON", , Hide
	Return
F13::
	commande := """C:\Program Files\mosquitto\mosquitto_pub.exe"" -h 192.168.1.25 -p 1883 -u xxxx -P xxxx -t ""unraid/attach-device-usb"" -m ""{\""domain\"": \""Work\"", \""vendorid\"": \""320f\"", \""pid\"": \""5041\"", \""dismount\"": true}"""
	Run, % commande, , Hide
	commande := """C:\Program Files\mosquitto\mosquitto_pub.exe"" -h 192.168.1.25 -p 1883 -u xxxx -P xxxx -t ""unraid/attach-device-usb"" -m ""{\""domain\"": \""Work\"", \""vendorid\"": \""1532\"", \""pid\"": \""0067\"", \""dismount\"": true}"""
	Run, % commande, , Hide
	Return
F14::
	commande := """C:\Program Files\mosquitto\mosquitto_pub.exe"" -h 192.168.1.25 -p 1883 -u xxxx -P xxxx -t ""unraid/attach-device-usb"" -m ""{\""domain\"": \""Game\"", \""vendorid\"": \""320f\"", \""pid\"": \""5041\"", \""dismount\"": true}"""
	Run, % commande, , Hide
	commande := """C:\Program Files\mosquitto\mosquitto_pub.exe"" -h 192.168.1.25 -p 1883 -u xxxx -P xxxx -t ""unraid/attach-device-usb"" -m ""{\""domain\"": \""Game\"", \""vendorid\"": \""1532\"", \""pid\"": \""0067\"", \""dismount\"": true}"""
	Run, % commande, , Hide
	Return

 

If someone have something simmilar i could use on linux vm, i would be interested.

  • Quote
    • Like 1
    • 1 month later...
    On 3/25/2025 at 10:11 PM, Nixx said:

    Ok, so maybe it's just me but i didn't found anything to do that so i try to build it myself.

     

    Basically, it will make the unraid server to suscribe to /unraid/attach-device-usb and you can send message like :

    {"domain": "Work", "vendorid": "320f", "pid": "5041", "dismount": true}
    Domain is the vm, vendorId/productId, the vid/pid of your usb device (you can use lsusb to list), dismount:true means it will detach to existing vm before try to attach it.

     

     

    To make it work, you need this plugin : 

     and a mqtt server.

     

     

    Here my script :  

    #!/bin/bash

# Load MQTT credentials from the configuration file
source /boot/config/mqttcredentials

# Check that all necessary variables are defined
if [[ -z "$MQTT_HOST" || -z "$MQTT_PORT" || -z "$MQTT_USER" || -z "$MQTT_PASSWORD" || -z "$MQTT_CLIENT_ID" ]]; then
  echo "Error: MQTT credentials are incomplete."
  exit 1
fi

# Function to handle messages from the 'unraid/switchkeyboard' topic
handle_switchkeyboard() {
  # Subscribe to the 'unraid/attach-device-usb' topic and print received messages with 'echo'
  mosquitto_sub -h $MQTT_HOST -p $MQTT_PORT -u $MQTT_USER -P $MQTT_PASSWORD -t "unraid/attach-device-usb" | while read -r message; do
    echo "Message received on 'unraid/attach-device-usb' : $message"

    # Parse the received JSON message
    domain=$(echo "$message" | jq -r '.domain')
    vendorid=$(echo "$message" | jq -r '.vendorid')
    pid=$(echo "$message" | jq -r '.pid')
    dismount=$(echo "$message" | jq -r '.dismount')

    # Check if the necessary information is present
    if [[ -z "$domain" || -z "$vendorid" || -z "$pid" ]]; then
      echo "Error: Missing information in MQTT message."
      continue
    fi

    # Create a temporary XML file for the device
    temp_file=$(mktemp /tmp/device_XXXX.xml)
    cat <<EOF > "$temp_file"
<hostdev mode='subsystem' type='usb'>
  <source>
    <vendor id='0x$vendorid'/>
    <product id='0x$pid'/>
  </source>
</hostdev>
EOF

    echo "Temporary file created: $temp_file"

    # Check if dismount is set to true and process accordingly
    if [[ "$dismount" == "true" ]]; then
      # Regex to check if a device with the given vendorid and pid is already attached to a domain
      device_attached_to_domain=""
      for domain_name in $(virsh list --all --name); do
        if [[ -n "$domain_name" ]]; then
          # Use a regex to search for vendorid and pid in the XML configuration of the domain
          device_attached=$(virsh dumpxml "$domain_name" | tr -d '\0' | \
            grep -Pzo "(?s)<hostdev.*<vendor id='0x$vendorid'.*<product id='0x$pid'")

          # If the device is found in the XML of this domain, mark it
          if [[ -n "$device_attached" ]]; then
            device_attached_to_domain="$domain_name"
            break
          fi
        fi
      done

      # If the device is attached to a different domain, detach it
      if [[ -n "$device_attached_to_domain" && "$device_attached_to_domain" != "$domain" ]]; then
        echo "Device is already attached to $device_attached_to_domain. Detaching it from there."
        virsh detach-device "$device_attached_to_domain" "$temp_file"
        # Wait for 2 seconds before attaching the device to the target domain
        sleep 2
      fi
    else
      echo "Dismount is set to false or not provided. Skipping dismount operation."
    fi

    # Check if the device is currently attached to the target domain
    device_in_use=$(virsh dumpxml "$domain" | tr -d '\0' | \
      grep -Pzo "(?s)<hostdev.*<vendor id='0x$vendorid'.*<product id='0x$pid'")

    if [[ -n "$device_in_use" ]]; then
      echo "Error: Device is already in use by domain '$domain'."
    else
      # Attach the device to the destination domain
      echo "Attaching device to virtual machine: $domain"
      virsh attach-device "$domain" "$temp_file"
    fi

    # Remove the temporary file
    rm -f "$temp_file"
  done
}

# Launch the function to handle the switchkeyboard topic
handle_switchkeyboard

     

    As a side note my windows vm i use a autohotscript like that, so i have key binding on my keyboard to switch beetween computers.
    I use dismount:false on the initial code, so it will only attach if it's not currently attached on an running vm. (and i put it into startup with autologin activated)
      

    commande := """C:\Program Files\mosquitto\mosquitto_pub.exe"" -h 192.168.1.25 -p 1883 -u xxxx -P xxxx -t ""unraid/attach-device-usb"" -m ""{\""domain\"": \""Work\"", \""vendorid\"": \""320f\"", \""pid\"": \""5041\"", \""dismount\"": false}"""
Run, % commande, , Hide
commande := """C:\Program Files\mosquitto\mosquitto_pub.exe"" -h 192.168.1.25 -p 1883 -u xxxx -P xxxx -t ""unraid/attach-device-usb"" -m ""{\""domain\"": \""Work\"", \""vendorid\"": \""1532\"", \""pid\"": \""0067\"", \""dismount\"": false}"""
Run, % commande, , Hide
F21::
	Run, "C:\Program Files\mosquitto\mosquitto_pub.exe" -h 192.168.1.25 -p 1883 -u xxxx -P xxxx -t "dpswitch/bouton" -m "ON", , Hide
	Return
F13::
	commande := """C:\Program Files\mosquitto\mosquitto_pub.exe"" -h 192.168.1.25 -p 1883 -u xxxx -P xxxx -t ""unraid/attach-device-usb"" -m ""{\""domain\"": \""Work\"", \""vendorid\"": \""320f\"", \""pid\"": \""5041\"", \""dismount\"": true}"""
	Run, % commande, , Hide
	commande := """C:\Program Files\mosquitto\mosquitto_pub.exe"" -h 192.168.1.25 -p 1883 -u xxxx -P xxxx -t ""unraid/attach-device-usb"" -m ""{\""domain\"": \""Work\"", \""vendorid\"": \""1532\"", \""pid\"": \""0067\"", \""dismount\"": true}"""
	Run, % commande, , Hide
	Return
F14::
	commande := """C:\Program Files\mosquitto\mosquitto_pub.exe"" -h 192.168.1.25 -p 1883 -u xxxx -P xxxx -t ""unraid/attach-device-usb"" -m ""{\""domain\"": \""Game\"", \""vendorid\"": \""320f\"", \""pid\"": \""5041\"", \""dismount\"": true}"""
	Run, % commande, , Hide
	commande := """C:\Program Files\mosquitto\mosquitto_pub.exe"" -h 192.168.1.25 -p 1883 -u xxxx -P xxxx -t ""unraid/attach-device-usb"" -m ""{\""domain\"": \""Game\"", \""vendorid\"": \""1532\"", \""pid\"": \""0067\"", \""dismount\"": true}"""
	Run, % commande, , Hide
	Return

     

    If someone have something simmilar i could use on linux vm, i would be interested.

     

    Awesome! That is an interesting use case! :) 

  • Quote

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