使用python从pyudev获取设备路径 [英] Obtain device path from pyudev with python

问题描述

使用pydev和python-2.7，我希望获得所连接设备的设备路径.

Using pydev with python-2.7, I wish obtain the device path of connected devices.

现在我使用此代码:

from pyudev.glib import GUDevMonitorObserver as MonitorObserver

def device_event(observer, action, device):
    print 'event {0} on device {1}'.format(action, device)

但是device返回这样的字符串:

but device return a string like this:

(u'/sys/devices/pci0000:00/pci0000:00:01.0/0000.000/usb1/1-2')

(u'/sys/devices/pci0000:00/pci0000:00:01.0/0000.000/usb1/1-2')

如何获取类似/dev/ttyUSB1的路径?

推荐答案

Device(u'/sys/devices/pci0000:00/pci0000:00:01.0/0000.000/usb1/1-2')是 USB设备(即device.device_type == 'usb_device').在进行枚举时，/dev/tty*文件尚不存在，因为稍后会在其自身枚举期间将其分配给其 child USB接口.因此，您需要为Device(u'/sys/devices/pci0000:00/pci0000:00:01.0/0000.000/usb1/1-2:1.0')等待一个单独的 device 添加事件，该事件将具有device.device_type == 'usb_interface'.

Device(u'/sys/devices/pci0000:00/pci0000:00:01.0/0000.000/usb1/1-2') is a USB device (i.e. device.device_type == 'usb_device'). At the time of its enumeration the /dev/tty* file does not exist yet as it gets assigned to its child USB interface later during its own enumeration. So you need to wait for a separate device added event for the Device(u'/sys/devices/pci0000:00/pci0000:00:01.0/0000.000/usb1/1-2:1.0') which would have device.device_type == 'usb_interface'.

然后您可以在其device_added()中执行print [os.path.join('/dev', f) for f in os.listdir(device.sys_path) if f.startswith('tty')]:

Then you could just do print [os.path.join('/dev', f) for f in os.listdir(device.sys_path) if f.startswith('tty')] in its device_added():

import os
import glib
import pyudev
import pyudev.glib

context = pyudev.Context()
monitor = pyudev.Monitor.from_netlink(context)
monitor.filter_by(subsystem='usb')
observer = pyudev.glib.GUDevMonitorObserver(monitor)

def device_added(observer, device):
    if device.device_type == "usb_interface":
        print device.sys_path, [os.path.join('/dev', f) for f in os.listdir(device.sys_path) if f.startswith('tty')]

observer.connect('device-added', device_added)
monitor.start()

mainloop = glib.MainLoop()
mainloop.run()

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