| # Copyright 2017 The Android Open Source Project |
| # |
| # Licensed under the Apache License, Version 2.0 (the "License"); |
| # you may not use this file except in compliance with the License. |
| # You may obtain a copy of the License at |
| # |
| # http://www.apache.org/licenses/LICENSE-2.0 |
| # |
| # Unless required by applicable law or agreed to in writing, software |
| # distributed under the License is distributed on an "AS IS" BASIS, |
| # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| # See the License for the specific language governing permissions and |
| # limitations under the License. |
| |
| """This module provides the serial number to USB location map on Linux.""" |
| import os |
| |
| |
| class SerialMapper(object): |
| """Maps serial number to its USB physical location. |
| |
| This class should run under Linux environment and use sysfs to enumerate the |
| USB devices. Use the serial file's content to create the map. |
| """ |
| |
| USB_DEVICES_PATH = '/sys/bus/usb/devices/' |
| |
| def __init__(self): |
| self.serial_map = {} |
| |
| def refresh_serial_map(self): |
| """Refresh the serial_number -> USB location map. |
| """ |
| serial_to_location_map = {} |
| # check if sysfs is mounted. |
| if not os.path.exists(self.USB_DEVICES_PATH): |
| return |
| |
| for device_folder_name in os.listdir(self.USB_DEVICES_PATH): |
| device_folder = os.path.join(self.USB_DEVICES_PATH, device_folder_name) |
| if os.path.isdir(device_folder): |
| # The format of folder name should be either: |
| # USB1, USB2... which are controllers (ignored). |
| # bus-port[.port.port] which are devices. |
| # bus-port[.port.port]:config.interface which are interfaces (ignored). |
| if ':' not in device_folder and '-' in device_folder: |
| serial_path = os.path.join(device_folder, 'serial') |
| if os.path.isfile(serial_path): |
| with open(serial_path) as f: |
| serial = f.readline().rstrip('\n').lower() |
| serial_to_location_map[serial] = device_folder_name |
| |
| self.serial_map = serial_to_location_map |
| |
| def get_location(self, serial): |
| """Get the USB location according to the serial number. |
| |
| Args: |
| serial: The serial number for the device. |
| Returns: |
| The USB physical location for the device. |
| """ |
| serial_lower = serial.lower() |
| if serial_lower in self.serial_map: |
| return self.serial_map[serial_lower] |
| return None |