b1ca39411b
This device will assist userspace to manage hotplug events. A userspace application reads a DeviceEvent entry until the return value is zero which indicates no events that are queued and waiting for processing. Trying to read with a buffer smaller than sizeof(DeviceEvent) results in EOVERFLOW. For now, there's no ioctl mechanism for this device but in the future an acknowledgement mechanism can be implemented via ioctl(2) interface.
53 lines
1.4 KiB
C++
53 lines
1.4 KiB
C++
/*
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* Copyright (c) 2021, Liav A. <liavalb@hotmail.co.il>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <Kernel/Devices/DeviceControlDevice.h>
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#include <Kernel/Devices/DeviceManagement.h>
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namespace Kernel {
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UNMAP_AFTER_INIT NonnullRefPtr<DeviceControlDevice> DeviceControlDevice::must_create()
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{
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auto device_control_device_or_error = DeviceManagement::try_create_device<DeviceControlDevice>();
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// FIXME: Find a way to propagate errors
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VERIFY(!device_control_device_or_error.is_error());
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return device_control_device_or_error.release_value();
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}
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bool DeviceControlDevice::can_read(const OpenFileDescription&, size_t) const
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{
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return true;
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}
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UNMAP_AFTER_INIT DeviceControlDevice::DeviceControlDevice()
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: CharacterDevice(2, 10)
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{
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}
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UNMAP_AFTER_INIT DeviceControlDevice::~DeviceControlDevice()
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{
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}
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ErrorOr<size_t> DeviceControlDevice::read(OpenFileDescription&, u64, UserOrKernelBuffer& buffer, size_t size)
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{
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auto device_event = DeviceManagement::the().dequeue_top_device_event({});
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if (!device_event.has_value())
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return 0;
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if (size < sizeof(DeviceEvent))
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return Error::from_errno(EOVERFLOW);
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size_t nread = 0;
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TRY(buffer.write(&device_event.value(), nread, sizeof(DeviceEvent)));
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nread += sizeof(DeviceEvent);
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return nread;
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}
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ErrorOr<void> DeviceControlDevice::ioctl(OpenFileDescription&, unsigned, Userspace<void*>)
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{
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return Error::from_errno(ENOTSUP);
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}
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}
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