pythonusbsubsystempyudev

Retrieve USB information using pyudev with device name


I retrieve the first device information from the block subsystem. For example that a USB stick was assigned to /dev/sdb. This is all the infos I can retrieve via the block subsystem:

[(u'DEVLINKS', u'/dev/disk/by-id/usb-Generic_Flash_Disk_63F2B6EC-0:0 /dev/disk/by-label/Fedora-Live-Desktop-x86_64-20-1 /dev/disk/by-path/pci-0000:00:1d.0-usb-0:1.2:1.0-scsi-0:0:0:0 /dev/disk/by-uu
id/2013-12-12-00-56-55-00'),
 (u'DEVNAME', u'/dev/sdb'),
 (u'DEVPATH', u'/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2/2-1.2:1.0/host74/target74:0:0/74:0:0:0/block/sdb'),
 (u'DEVTYPE', u'disk'), (u'ID_BUS', u'usb'), 
 (u'ID_FS_APPLICATION_ID', u'GENISOIMAGE\\x20ISO\\x209660\\x2fHFS\\x20FILESYSTEM\\x20CREATOR\\x20\\x28C\\x29\\x201993\\x20E.YOUNGDALE\\x20\\x28C\\x29\\x201997-2006\\x20J.PEARSON\\x2fJ.SCHILLING\\x20\\x28C\\x29\\x202006-2007\\x20CDRKIT\\x20TEAM'), 
 (u'ID_FS_BOOT_SYSTEM_ID', u'EL\\x20TORITO\\x20SPECIFICATION'), 
 (u'ID_FS_LABEL', u'Fedora-Live-Desktop-x86_64-20-1'),  
 (u'ID_FS_LABEL_ENC', u'Fedora-Live-Desktop-x86_64-20-1'), 
 (u'ID_FS_SYSTEM_ID', u'LINUX'), 
 (u'ID_FS_TYPE', u'iso9660'), 
 (u'ID_FS_USAGE', u'filesystem'), 
 (u'ID_FS_UUID', u'2013-12-12-00-56-55-00'), 
 (u'ID_FS_UUID_ENC', u'2013-12-12-00-56-55-00'), 
 (u'ID_FS_VERSION', u'Joliet Extension'), 
 (u'ID_INSTANCE', u'0:0'), 
 (u'ID_MODEL', u'Flash_Disk'), 
 (u'ID_MODEL_ENC', u'Flash\\x20Disk\\x20\\x20\\x20\\x20\\x20\\x20'), 
 (u'ID_MODEL_ID', u'6387'), 
 (u'ID_PART_TABLE_TYPE', u'dos'), 
 (u'ID_PART_TABLE_UUID', u'5513338d'), 
 (u'ID_PATH', u'pci-0000:00:1d.0-usb-0:1.2:1.0-scsi-0:0:0:0'), 
 (u'ID_PATH_TAG', u'pci-0000_00_1d_0-usb-0_1_2_1_0-scsi-0_0_0_0'), 
 (u'ID_REVISION', u'8.07'), 
 (u'ID_SERIAL', u'Generic_Flash_Disk_63F2B6EC-0:0'),
 (u'ID_SERIAL_SHORT', u'63F2B6EC'), 
 (u'ID_TYPE', u'disk'), 
 (u'ID_USB_DRIVER', u'usb-storage'), 
 (u'ID_USB_INTERFACES', u':080650:'), 
 (u'ID_USB_INTERFACE_NUM', u'00'), 
 (u'ID_VENDOR', u'Generic'), 
 (u'ID_VENDOR_ENC', u'Generic\\x20'), 
 (u'ID_VENDOR_ID', u'058f'), 
 (u'MAJOR', u'8'),
 (u'MINOR', u'16'), 
 (u'MPATH_SBIN_PATH', u'/sbin'), 
 (u'SUBSYSTEM', u'block'), 
 (u'TAGS', u':systemd:'), 
 (u'UDISKS_PRESENTATION_NOPOLICY', u'0'), 
 (u'USEC_INITIALIZED', u'7197321174')]

I want to get some detailed information from the usb subsystem. But how can I find my USB device with the information I retrieved from the block subsystem?


Solution

  • PyUSB would be a good address for detailed USB information indeed. But I use pyudev to monitor the insertion of USB removable devices. So I tried to do all I need with one library.. Here is a code that works but is ugly (as you can see I can extract all information I want using pyudev except the usb size/capacity):

    import glib
    
    from pyudev import Context, Monitor
    import pyudev
    import subprocess 
    
    def get_block_infos(dev_name):
        dev = pyudev.Device.from_device_file(context, dev_name)
    
    
        try:
            objProc = subprocess.Popen('lsblk --nodeps %s | grep -v SIZE  | awk \'{ print $4 }\'' % dev.get('DEVNAME'), shell=True, bufsize=0, executable="/bin/bash", stdin=None, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
        except OSError, e:
            print(e)
    
        #  stdOut.communicate() --> dimension [0]: stdout, dimenstion [1]: stderr
        stdOut = objProc.communicate()
    
        print('<BLOCK INFORMATION>')
        print('Device name: %s' % dev.get('DEVNAME'))
        print('Device type: %s' % dev.get('DEVTYPE'))
        print('Bus system: %s' % dev.get('ID_BUS'))
        print('Partition label: %s' % dev.get('ID_FS_LABEL'))
        print('FS: %s' % dev.get('ID_FS_SYSTEM_ID'))
        print('FS type: %s' % dev.get('ID_FS_TYPE'))
        print('Device usage: %s' % dev.get('ID_FS_USAGE'))
        print('Device model: %s' % dev.get('ID_MODEL'))
        print('Partition type: %s' % dev.get('ID_PART_TABLE_TYPE'))
        print('USB driver: %s' % dev.get('ID_USB_DRIVER'))
        print('Path id: %s' % dev.get('ID_PATH'))
        print('Capacity: %s' % stdOut[0].strip())
        print('</BLOCK INFORMATION>')
    
    def get_usb_infos(dev_path):
        print('<USB INFORMATION>')
    
        usb_removable_device = None
    
        # deprecated and removed from dbus
        # print(pyudev.Device.from_path(context, id_path))  
        # because I found no other documented way, I iterate
        # over all  devices and match my pci path..
        for device in context.list_devices(subsystem='usb'):
            usb_dev_path = device.get('DEVPATH')
    
            if dev_path.startswith(usb_dev_path):
                # this matches the usb hub,
                # the usb controller and
                # in third place the usb stick
                # so lets watch out for the
                # longest/most precise match
    
            try:
                if len(usb_dev_path) > len(usb_removable_device.get('DEVPATH')):
                    usb_removable_device = device
            except AttributeError:
                # ignore because in first loop
                # usb_removable_device is None and
                # there is no usb_removable_device.get() attrib
                usb_removable_device = device
    
            # get more information with usb_removable_device.items()
            print('Vendor: %s' % usb_removable_device.get('ID_VENDOR_FROM_DATABASE'))
            print('</USB INFORMATION>')
    
    try:
        from pyudev.glib import MonitorObserver
    
        def device_event(observer, device):
            get_block_infos(device.get('DEVNAME'))
            get_usb_infos(device.get('DEVPATH'))
    except:
        from pyudev.glib import GUDevMonitorObserver as MonitorObserver
    
        def device_event(observer, action, device):
            get_block_infos(device.get('DEVNAME'))
            get_usb_infos(device.get('DEVPATH'))
    
    
    context = Context()
    monitor = Monitor.from_netlink(context)
    
    monitor.filter_by(subsystem='block')
    observer = MonitorObserver(monitor)
    
    observer.connect('device-event', device_event)
    monitor.start()
    
    glib.MainLoop().run()
    

    An example output of this script would be:

    <BLOCK INFORMATION>
    Device name: /dev/sdb
    Device type: disk
    Bus system: usb
    Partition label: CentOS-6.5-x86_64-LiveCD
    FS: LINUX
    FS type: iso9660
    Device usage: filesystem
    Device model: Patriot_Memory
    Partition type: dos
    USB driver: usb-storage
    Path id: pci-0000:00:1d.0-usb-0:1.2:1.0-scsi-0:0:0:0
    Capacity: 14.5G
    </BLOCK INFORMATION>
    <USB INFORMATION>
    Vendor: Kingston Technology Company Inc.
    </USB INFORMATION>
    <BLOCK INFORMATION>
    Device name: /dev/sdb1
    Device type: partition
    Bus system: usb
    Partition label: CentOS-6.5-x86_64-LiveCD
    FS: LINUX
    FS type: ext4
    Device usage: filesystem
    Device model: Patriot_Memory
    Partition type: dos
    USB driver: usb-storage
    Path id: pci-0000:00:1d.0-usb-0:1.2:1.0-scsi-0:0:0:0
    Capacity: 14.4G
    </BLOCK INFORMATION>
    <USB INFORMATION>
    Vendor: Kingston Technology Company Inc.
    </USB INFORMATION>