385 lines
16 KiB
Python
385 lines
16 KiB
Python
# Copyright 2009-2017 Wander Lairson Costa
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# Copyright 2009-2021 PyUSB contributors
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#
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# Redistribution and use in source and binary forms, with or without
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# modification, are permitted provided that the following conditions are
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# met:
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#
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# 1. Redistributions of source code must retain the above copyright
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# notice, this list of conditions and the following disclaimer.
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#
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# 2. Redistributions in binary form must reproduce the above copyright
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# notice, this list of conditions and the following disclaimer in the
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# documentation and/or other materials provided with the distribution.
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#
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# 3. Neither the name of the copyright holder nor the names of its
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# contributors may be used to endorse or promote products derived from
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# this software without specific prior written permission.
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#
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# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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# HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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r"""usb.backend - Backend interface.
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This module exports:
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IBackend - backend interface.
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Backends are Python objects which implement the IBackend interface.
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The easiest way to do so is inherinting from IBackend.
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PyUSB already provides backends for libusb versions 0.1 and 1.0,
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and OpenUSB library. Backends modules included with PyUSB are required to
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export the get_backend() function, which returns an instance of a backend
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object. You can provide your own customized backend if you
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want to. Below you find a skeleton of a backend implementation module:
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import usb.backend
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class MyBackend(usb.backend.IBackend):
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pass
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def get_backend():
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return MyBackend()
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You can use your customized backend by passing it as the backend parameter of the
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usb.core.find() function. For example:
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import custom_backend
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import usb.core
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myidVendor = 0xfffe
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myidProduct = 0x0001
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mybackend = custom_backend.get_backend()
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dev = usb.core.find(backend = mybackend, idProduct=myidProduct,
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idVendor=myidVendor)
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For custom backends, you are not required to supply the get_backend() function,
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since the application code will instantiate the backend.
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If you do not provide a backend to the find() function, it will use one of the
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defaults backend according to its internal rules. For details, consult the
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find() function documentation.
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"""
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import usb._objfinalizer as _objfinalizer
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__author__ = 'Wander Lairson Costa'
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__all__ = ['IBackend', 'libusb0', 'libusb1', 'openusb']
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def _not_implemented(func):
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raise NotImplementedError(func.__name__)
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class IBackend(_objfinalizer.AutoFinalizedObject):
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r"""Backend interface.
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IBackend is the basic interface for backend implementations. By default,
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the methods of the interface raise a NotImplementedError exception. A
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backend implementation should replace the methods to provide the funcionality
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necessary.
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As Python is a dynamic typed language, you are not obligated to inherit from
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IBackend: everything that behaves like an IBackend is an IBackend. But you
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are strongly recommended to do so, inheriting from IBackend provides consistent
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default behavior.
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"""
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def enumerate_devices(self):
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r"""This function is required to return an iterable object which
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yields an implementation defined device identification for each
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USB device found in the system.
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The device identification object is used as argument to other methods
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of the interface.
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"""
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_not_implemented(self.enumerate_devices)
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def get_parent(self, dev):
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"""Return the parent device of the given device."""
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_not_implemented(self.get_parent)
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def get_device_descriptor(self, dev):
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r"""Return the device descriptor of the given device.
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The object returned is required to have all the Device Descriptor
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fields accessible as member variables. They must be convertible (but
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not required to be equal) to the int type.
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dev is an object yielded by the iterator returned by the enumerate_devices()
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method.
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"""
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_not_implemented(self.get_device_descriptor)
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def get_configuration_descriptor(self, dev, config):
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r"""Return a configuration descriptor of the given device.
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The object returned is required to have all the Configuration Descriptor
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fields acessible as member variables. They must be convertible (but
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not required to be equal) to the int type.
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The dev parameter is the device identification object.
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config is the logical index of the configuration (not the bConfigurationValue
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field). By "logical index" we mean the relative order of the configurations
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returned by the peripheral as a result of GET_DESCRIPTOR request.
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"""
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_not_implemented(self.get_configuration_descriptor)
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def get_interface_descriptor(self, dev, intf, alt, config):
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r"""Return an interface descriptor of the given device.
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The object returned is required to have all the Interface Descriptor
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fields accessible as member variables. They must be convertible (but
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not required to be equal) to the int type.
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The dev parameter is the device identification object.
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The intf parameter is the interface logical index (not the bInterfaceNumber field)
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and alt is the alternate setting logical index (not the bAlternateSetting value).
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Not every interface has more than one alternate setting. In this case, the alt
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parameter should be zero. config is the configuration logical index (not the
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bConfigurationValue field).
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"""
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_not_implemented(self.get_interface_descriptor)
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def get_endpoint_descriptor(self, dev, ep, intf, alt, config):
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r"""Return an endpoint descriptor of the given device.
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The object returned is required to have all the Endpoint Descriptor
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fields acessible as member variables. They must be convertible (but
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not required to be equal) to the int type.
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The ep parameter is the endpoint logical index (not the bEndpointAddress
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field) of the endpoint descriptor desired. dev, intf, alt and config are the same
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values already described in the get_interface_descriptor() method.
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"""
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_not_implemented(self.get_endpoint_descriptor)
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def open_device(self, dev):
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r"""Open the device for data exchange.
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This method opens the device identified by the dev parameter for communication.
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This method must be called before calling any communication related method, such
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as transfer methods.
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It returns a handle identifying the communication instance. This handle must be
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passed to the communication methods.
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"""
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_not_implemented(self.open_device)
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def close_device(self, dev_handle):
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r"""Close the device handle.
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This method closes the device communication channel and releases any
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system resources related to it.
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"""
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_not_implemented(self.close_device)
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def set_configuration(self, dev_handle, config_value):
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r"""Set the active device configuration.
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This method should be called to set the active configuration
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of the device. The dev_handle parameter is the value returned
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by the open_device() method and the config_value parameter is the
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bConfigurationValue field of the related configuration descriptor.
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"""
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_not_implemented(self.set_configuration)
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def get_configuration(self, dev_handle):
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r"""Get the current active device configuration.
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This method returns the bConfigurationValue of the currently
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active configuration. Depending on the backend and the OS,
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either a cached value may be returned or a control request may
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be issued. The dev_handle parameter is the value returned by
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the open_device method.
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"""
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_not_implemented(self.get_configuration)
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def set_interface_altsetting(self, dev_handle, intf, altsetting):
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r"""Set the interface alternate setting.
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This method should only be called when the interface has more than
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one alternate setting. The dev_handle is the value returned by the
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open_device() method. intf and altsetting are respectively the
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bInterfaceNumber and bAlternateSetting fields of the related interface.
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"""
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_not_implemented(self.set_interface_altsetting)
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def claim_interface(self, dev_handle, intf):
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r"""Claim the given interface.
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Interface claiming is not related to USB spec itself, but it is
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generally an necessary call of the USB libraries. It requests exclusive
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access to the interface on the system. This method must be called
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before using one of the transfer methods.
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dev_handle is the value returned by the open_device() method and
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intf is the bInterfaceNumber field of the desired interface.
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"""
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_not_implemented(self.claim_interface)
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def release_interface(self, dev_handle, intf):
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r"""Release the claimed interface.
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dev_handle and intf are the same parameters of the claim_interface
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method.
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"""
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_not_implemented(self.release_interface)
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def bulk_write(self, dev_handle, ep, intf, data, timeout):
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r"""Perform a bulk write.
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dev_handle is the value returned by the open_device() method.
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The ep parameter is the bEndpointAddress field whose endpoint
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the data will be sent to. intf is the bInterfaceNumber field
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of the interface containing the endpoint. The data parameter
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is the data to be sent. It must be an instance of the array.array
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class. The timeout parameter specifies a time limit to the operation
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in milliseconds.
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The method returns the number of bytes written.
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"""
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_not_implemented(self.bulk_write)
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def bulk_read(self, dev_handle, ep, intf, buff, timeout):
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r"""Perform a bulk read.
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dev_handle is the value returned by the open_device() method.
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The ep parameter is the bEndpointAddress field whose endpoint
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the data will be received from. intf is the bInterfaceNumber field
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of the interface containing the endpoint. The buff parameter
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is the buffer to receive the data read, the length of the buffer
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tells how many bytes should be read. The timeout parameter
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specifies a time limit to the operation in milliseconds.
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The method returns the number of bytes actually read.
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"""
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_not_implemented(self.bulk_read)
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def intr_write(self, dev_handle, ep, intf, data, timeout):
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r"""Perform an interrupt write.
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dev_handle is the value returned by the open_device() method.
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The ep parameter is the bEndpointAddress field whose endpoint
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the data will be sent to. intf is the bInterfaceNumber field
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of the interface containing the endpoint. The data parameter
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is the data to be sent. It must be an instance of the array.array
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class. The timeout parameter specifies a time limit to the operation
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in milliseconds.
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The method returns the number of bytes written.
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"""
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_not_implemented(self.intr_write)
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def intr_read(self, dev_handle, ep, intf, size, timeout):
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r"""Perform an interrupt read.
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dev_handle is the value returned by the open_device() method.
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The ep parameter is the bEndpointAddress field whose endpoint
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the data will be received from. intf is the bInterfaceNumber field
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of the interface containing the endpoint. The buff parameter
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is the buffer to receive the data read, the length of the buffer
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tells how many bytes should be read. The timeout parameter
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specifies a time limit to the operation in milliseconds.
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The method returns the number of bytes actually read.
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"""
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_not_implemented(self.intr_read)
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def iso_write(self, dev_handle, ep, intf, data, timeout):
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r"""Perform an isochronous write.
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dev_handle is the value returned by the open_device() method.
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The ep parameter is the bEndpointAddress field whose endpoint
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the data will be sent to. intf is the bInterfaceNumber field
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of the interface containing the endpoint. The data parameter
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is the data to be sent. It must be an instance of the array.array
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class. The timeout parameter specifies a time limit to the operation
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in milliseconds.
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The method returns the number of bytes written.
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"""
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_not_implemented(self.iso_write)
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def iso_read(self, dev_handle, ep, intf, size, timeout):
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r"""Perform an isochronous read.
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dev_handle is the value returned by the open_device() method.
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The ep parameter is the bEndpointAddress field whose endpoint
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the data will be received from. intf is the bInterfaceNumber field
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of the interface containing the endpoint. The buff parameter
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is buffer to receive the data read, the length of the buffer tells
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how many bytes should be read. The timeout parameter specifies
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a time limit to the operation in milliseconds.
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The method returns the number of bytes actually read.
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"""
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_not_implemented(self.iso_read)
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def ctrl_transfer(self,
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dev_handle,
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bmRequestType,
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bRequest,
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wValue,
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wIndex,
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data,
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timeout):
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r"""Perform a control transfer on the endpoint 0.
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The direction of the transfer is inferred from the bmRequestType
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field of the setup packet.
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dev_handle is the value returned by the open_device() method.
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bmRequestType, bRequest, wValue and wIndex are the same fields
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of the setup packet. data is an array object, for OUT requests
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it contains the bytes to transmit in the data stage and for
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IN requests it is the buffer to hold the data read. The number
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of bytes requested to transmit or receive is equal to the length
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of the array times the data.itemsize field. The timeout parameter
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specifies a time limit to the operation in milliseconds.
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Return the number of bytes written (for OUT transfers) or the data
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read (for IN transfers), as an array.array object.
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"""
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_not_implemented(self.ctrl_transfer)
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def clear_halt(self, dev_handle, ep):
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r"""Clear the halt/stall condition for the endpoint."""
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_not_implemented(self.clear_halt)
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def reset_device(self, dev_handle):
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r"""Reset the device."""
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_not_implemented(self.reset_device)
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def is_kernel_driver_active(self, dev_handle, intf):
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r"""Determine if a kernel driver is active on an interface.
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If a kernel driver is active, you cannot claim the interface,
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and the backend will be unable to perform I/O.
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"""
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_not_implemented(self.is_kernel_driver_active)
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def detach_kernel_driver(self, dev_handle, intf):
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r"""Detach a kernel driver from an interface.
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If successful, you will then be able to claim the interface
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and perform I/O.
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"""
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_not_implemented(self.detach_kernel_driver)
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def attach_kernel_driver(self, dev_handle, intf):
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r"""Re-attach an interface's kernel driver, which was previously
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detached using detach_kernel_driver()."""
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_not_implemented(self.attach_kernel_driver)
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