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https://github.com/SerenityOS/serenity
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16244c490a
We used to allocate major numbers quite randomly, with no common place to look them up if needed. This commit is changing that by placing all major number allocations under a new C++ namespace, in the API/MajorNumberAllocation.h file. We also add the foundations of what is needed before we can publish this information (allocated numbers for block and char devices) to userspace.
46 lines
1.1 KiB
C++
46 lines
1.1 KiB
C++
/*
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* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <Kernel/API/MajorNumberAllocation.h>
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#include <Kernel/Devices/DeviceManagement.h>
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#include <Kernel/Devices/Generic/ZeroDevice.h>
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#include <Kernel/Sections.h>
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namespace Kernel {
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UNMAP_AFTER_INIT NonnullLockRefPtr<ZeroDevice> ZeroDevice::must_create()
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{
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auto zero_device_or_error = DeviceManagement::try_create_device<ZeroDevice>();
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// FIXME: Find a way to propagate errors
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VERIFY(!zero_device_or_error.is_error());
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return zero_device_or_error.release_value();
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}
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UNMAP_AFTER_INIT ZeroDevice::ZeroDevice()
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: CharacterDevice(MajorAllocation::CharacterDeviceFamily::Generic, 5)
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{
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}
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UNMAP_AFTER_INIT ZeroDevice::~ZeroDevice() = default;
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bool ZeroDevice::can_read(OpenFileDescription const&, u64) const
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{
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return true;
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}
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ErrorOr<size_t> ZeroDevice::read(OpenFileDescription&, u64, UserOrKernelBuffer& buffer, size_t size)
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{
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TRY(buffer.memset(0, size));
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return size;
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}
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ErrorOr<size_t> ZeroDevice::write(OpenFileDescription&, u64, UserOrKernelBuffer const&, size_t size)
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{
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return size;
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}
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}
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