IOCTL_USB_GET_ROOT_HUB_NAME control code
The IOCTL_USB_GET_ROOT_HUB_NAME I/O control request is used with the USB_ROOT_HUB_NAME structure to retrieve the symbolic link name of the root hub.
IOCTL_USB_GET_ROOT_HUB_NAME is a user-mode I/O control request. This request targets the USB host controller (GUID_DEVINTERFACE_USB_HOST_CONTROLLER).
On output, the AssociatedIrp.SystemBuffer member points to a USB_ROOT_HUB_NAME structure that contains the symbolic link name of the root hub. The leading "\xxx\ " text is not included in the retrieved string.
The USB stack sets Irp->IoStatus.Status to STATUS_SUCCESS if the request is successful. Otherwise, the USB stack sets Status to the appropriate error condition, such as STATUS_INVALID_PARAMETER or STATUS_INSUFFICIENT_RESOURCES.
If the root hub is removed or stopped, the request returns STATUS_SUCCESS but the string is NULL.