Python 获取 USB 描述符？

Question

我的python代码如下

#!/usr/bin/env python

from __future__ import print_function
import argparse
import string
import struct
import sys

import win32api
import win32file
import pywintypes


def CTL_CODE(DeviceType, Function, Method, Access):
    return (DeviceType << 16) | (Access << 14) | (Function << 2) | Method
def USB_CTL(id):
   # CTL_CODE(FILE_DEVICE_USB, (id), METHOD_BUFFERED, FILE_ANY_ACCESS)
    return CTL_CODE(0x22, id, 0, 0)

IOCTL_USB_GET_ROOT_HUB_NAME = USB_CTL(258)                   # HCD_GET_ROOT_HUB_NAME
IOCTL_USB_GET_NODE_INFORMATION = USB_CTL(258)                # USB_GET_NODE_INFORMATION
IOCTL_USB_GET_NODE_CONNECTION_INFORMATION = USB_CTL(259)     # USB_GET_NODE_CONNECTION_INFORMATION
IOCTL_USB_GET_NODE_CONNECTION_DRIVERKEY_NAME = USB_CTL(264)  # USB_GET_NODE_CONNECTION_DRIVERKEY_NAME
IOCTL_USB_GET_NODE_CONNECTION_NAME = USB_CTL(261)            # USB_GET_NODE_CONNECTION_NAME
IOCTL_USB_GET_DESCRIPTOR_FROM_NODE_CONNECTION = USB_CTL(260) # USB_GET_DESCRIPTOR_FROM_NODE_CONNECTION

USB_CONFIGURATION_DESCRIPTOR_TYPE = 2
USB_STRING_DESCRIPTOR_TYPE = 3
USB_INTERFACE_DESCRIPTOR_TYPE = 4
MAXIMUM_USB_STRING_LENGTH = 255


def open_dev(name):
    try:
        handle = win32file.CreateFile(name,
                                  win32file.GENERIC_WRITE,
                                  win32file.FILE_SHARE_WRITE,
                                  None,
                                  win32file.OPEN_EXISTING,
                                  0,
                                  None)
    except pywintypes.error as e:
        return None
    return handle


def get_root_hub_name(handle):
    buf = win32file.DeviceIoControl(handle,
                                IOCTL_USB_GET_ROOT_HUB_NAME,
                                None,
                                6,
                                None)
    act_len, _ = struct.unpack('LH', buf)
    buf = win32file.DeviceIoControl(handle,
                                IOCTL_USB_GET_ROOT_HUB_NAME,
                                None,
                                act_len,
                                None)
    return buf[4:].decode('utf-16le')


def get_driverkey_name(handle, index):
    key_name = chr(index) + '\0'*9
    try:
        buf = win32file.DeviceIoControl(handle,
                                    IOCTL_USB_GET_NODE_CONNECTION_DRIVERKEY_NAME,
                                    key_name,
                                    10,
                                    None)
    except pywintypes.error as e:
        print(e.strerror, index)
        sys.exit(1)
    _, act_len, _ = struct.unpack('LLH', buf)
    buf = win32file.DeviceIoControl(handle,
                                IOCTL_USB_GET_NODE_CONNECTION_DRIVERKEY_NAME,
                                key_name,
                                act_len,
                                None)
    return buf[8:].decode('utf-16le')


def get_ext_hub_name(handle, index):
    hub_name = chr(index) + '\0'*9
    buf = win32file.DeviceIoControl(handle,
                                IOCTL_USB_GET_NODE_CONNECTION_NAME,
                                hub_name,
                                10,
                                None)
    _, act_len, _ = struct.unpack('LLH', buf)
    buf = win32file.DeviceIoControl(handle,
                                IOCTL_USB_GET_NODE_CONNECTION_NAME,
                                hub_name,
                                act_len,
                                None)
    return buf[8:].decode('utf-16le')


def get_str_desc(handle, conn_idx, str_idx):
    req = struct.pack('LBBHHH',
                  conn_idx,
                  0,
                  0,
                  (USB_STRING_DESCRIPTOR_TYPE<<8) | str_idx,
                  win32api.GetSystemDefaultLangID(),
                  12+MAXIMUM_USB_STRING_LENGTH)
    try:
        buf = win32file.DeviceIoControl(handle,
                                    IOCTL_USB_GET_DESCRIPTOR_FROM_NODE_CONNECTION,
                                    req,
                                    12+MAXIMUM_USB_STRING_LENGTH,
                                    None)
    except pywintypes.error as e:
         return 'ERROR: no String Descriptor for index {}'.format(str_idx)
    if len(buf) > 16:
        return buf[14:].decode('utf-16le')
    return ''


def exam_hub(name, verbose, level):
    handle = open_dev(r'\\.\{}'.format(name))
    if not handle:
        print('Failed to open device {}'.format(name))
        return
    buf = win32file.DeviceIoControl(handle,
                                IOCTL_USB_GET_NODE_INFORMATION,
                                None,
                                76,
                                None)
    print_hub_ports(handle, ord(buf[6]), verbose, level)
    handle.close()


def print_str_or_hex(to_be_print):
    if all(c in string.printable for c in to_be_print):
        print('"{}"'.format(to_be_print))
        return
    print('Hex: ', end='')
    for x in to_be_print:
        print('{:02x} '.format(ord(x)), end='')
    print('')


def print_hub_ports(handle, num_ports, verbose, level):
    for idx in range(1, num_ports+1):
        info = chr(idx) + '\0'*34
        try:
            buf = win32file.DeviceIoControl(handle,
                                        IOCTL_USB_GET_NODE_CONNECTION_INFORMATION,
                                        info,
                                        34 + 11*30,
                                        None)
        except pywintypes.error as e:
            print(e.winerror, e.funcname, e.strerror)
            return

       _, vid, pid, vers, manu, prod, seri, _, ishub, _, stat = struct.unpack('=12sHHHBBB3s?6sL', buf[:35])

        if ishub:
            if verbose:
                print('{}  [Port{}] {}'.format('  '*level, idx, 'USB Hub'))
            exam_hub(get_ext_hub_name(handle, idx), verbose, level)
       elif stat == 0 and verbose:
            print('{}  [Port{}] {}'.format('  '*level, idx, 'NoDeviceConnected'))
        elif stat == 1:
            if verbose or (manu != 0 or prod != 0 or seri != 0):
                print('{}  [Port{}] {}'.format('  '*level, idx, get_driverkey_name(handle, idx)))
                print('{}    Vendor ID:    0x{:04X}'.format('  '*level, vid))
                print('{}    Product ID:  0x{:04X}'.format('  '*level, pid))
                print('{}    Device BCD:  0x{:04X}'.format('  '*level, vers))
                if manu != 0:
                    print('{}    Manufacturer (0x{:x}) -> '.format('  '*level, manu), end='')
                    print_str_or_hex(get_str_desc(handle, idx, manu))
                if prod != 0:
                    print('{}    Product      (0x{:x}) -> '.format('  '*level, prod), end='')
                    print_str_or_hex(get_str_desc(handle, idx, prod))
                if seri != 0:
                    print('{}    Serial No    (0x{:x}) -> '.format('  '*level, seri), end='') 
                    print_str_or_hex(get_str_desc(handle, idx, seri))


def main():
    parser = argparse.ArgumentParser()
    parser.add_argument('-v', '--verbose', action='store_true',
                    help="Increase output verbosity.")
    args = parser.parse_args()

    for i in range(10):
        name = r"\\.\HCD{}".format(i)
        handle = open_dev(name)
        if not handle:
            continue

        root = get_root_hub_name(handle)
        print('{}RootHub: {}'.format('\n' if i != 0 else '', root))

        dev_name = r'\\.\{}'.format(root)
        dev_handle = open_dev(dev_name)
        if not dev_handle:
            print('Failed to open device {}'.format(dev_name))
            continue

        buf = win32file.DeviceIoControl(dev_handle,
                                    IOCTL_USB_GET_NODE_INFORMATION,
                                    None,
                                    76,
                                    None)
        print_hub_ports(dev_handle, ord(buf[6]), args.verbose, 0)
        dev_handle.close()
        handle.close()

if __name__ == '__main__':
    main()

返回是：

RootHub：USB#ROOT_HUB20#4&2c86c80d&0#{f18a0e88-c30c-11d0-8815-00a0c906bed8}

[端口2] {36fc9e60-c465-11cf-8056-444553540000}\0009

供应商 ID：0x2232

产品 ID：0x6001

设备 BCD：0x0002

制造商 (0x1) -> “错误：索引 1 没有字符串描述符”

产品 (0x2) -> “错误：索引 2 没有字符串描述符”

问题是：如何获得制造商和产品编号？

Answer 1

这个设备可能没有提供任何字符串描述符。

虽然字符串描述符（iManufacturer、iProduct、iSerialNumber）的索引应该为零以表明没有字符串，但许多设备会像您看到的那样报告不正确的（非零）索引。我相信除了请求供应商帮助升级其固件之外，您无能为力。

但是，供应商 ID 和产品 ID 提供了您需要的信息。 供应商 ID 0x2232 将是 Silicon Motion 和产品 ID 0x6001 我不确定它是什么，也许您还需要与供应商核实。

Answer 2

您的代码非常接近您想要的（以及我需要的）。问题在于打包的 iocontrolcode 结构中传递的缓冲区长度。它需要是MAXIMUM_USB_STRING_LENGTH 而不是12+MAXIMUM_USB_STRING_LENGTH，如下所示。
请注意，我在代码中留下了注释掉的 print(e) 语句。这指出了我的问题，因为生成的错误消息抱怨缓冲区大小不正确。

def get_str_desc(handle, conn_idx, str_idx):
    req = struct.pack('LBBHHH',
                  conn_idx,
                  0,
                  0,
                  (USB_STRING_DESCRIPTOR_TYPE<<8) | str_idx,
                  win32api.GetSystemDefaultLangID(),
                  MAXIMUM_USB_STRING_LENGTH)
    try:
        buf = win32file.DeviceIoControl(handle,
                                    IOCTL_USB_GET_DESCRIPTOR_FROM_NODE_CONNECTION,
                                    req,
                                    12+MAXIMUM_USB_STRING_LENGTH,
                                    None)
    except pywintypes.error as e:
        #print(e)
        return 'ERROR: no String Descriptor for index {}'.format(str_idx)
    if len(buf) > 16:
        return buf[14:].decode('utf-16le')
    return ''

通过此更改，现在将显示制造商、产品和序列字符串（如果可用）。