mirror of
https://github.com/SerenityOS/serenity
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99 lines
3.4 KiB
C++
99 lines
3.4 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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#pragma once
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// Device is the base class of everything that lives in the /dev directory.
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//
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// To expose a Device to the filesystem, simply pass two unique numbers to the constructor,
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// and then mknod a file in /dev with those numbers.
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//
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// There are two main subclasses:
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// - BlockDevice (random access)
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// - CharacterDevice (sequential)
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#include <AK/DoublyLinkedList.h>
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#include <AK/Error.h>
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#include <AK/Function.h>
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#include <AK/HashMap.h>
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#include <Kernel/API/DeviceFileTypes.h>
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#include <Kernel/Devices/AsyncDeviceRequest.h>
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#include <Kernel/FileSystem/File.h>
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#include <Kernel/FileSystem/SysFS/Registry.h>
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#include <Kernel/FileSystem/SysFS/Subsystems/DeviceIdentifiers/DeviceComponent.h>
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#include <Kernel/FileSystem/SysFS/Subsystems/DeviceIdentifiers/SymbolicLinkDeviceComponent.h>
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#include <Kernel/Library/LockRefPtr.h>
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#include <Kernel/UnixTypes.h>
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namespace Kernel {
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class Device : public File {
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protected:
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enum class State {
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Normal,
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BeingRemoved,
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};
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public:
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virtual ~Device() override;
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MajorNumber major() const { return m_major; }
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MinorNumber minor() const { return m_minor; }
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virtual ErrorOr<NonnullOwnPtr<KString>> pseudo_path(OpenFileDescription const&) const override;
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virtual ErrorOr<NonnullRefPtr<OpenFileDescription>> open(int options) override;
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virtual bool is_device() const override { return true; }
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virtual void will_be_destroyed() override;
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virtual ErrorOr<void> after_inserting();
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virtual bool is_openable_by_jailed_processes() const { return false; }
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void process_next_queued_request(Badge<AsyncDeviceRequest>, AsyncDeviceRequest const&);
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template<typename AsyncRequestType, typename... Args>
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ErrorOr<NonnullLockRefPtr<AsyncRequestType>> try_make_request(Args&&... args)
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{
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auto request = TRY(adopt_nonnull_lock_ref_or_enomem(new (nothrow) AsyncRequestType(*this, forward<Args>(args)...)));
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SpinlockLocker lock(m_requests_lock);
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bool was_empty = m_requests.is_empty();
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TRY(m_requests.try_append(request));
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if (was_empty)
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request->do_start(move(lock));
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return request;
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}
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protected:
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Device(MajorNumber major, MinorNumber minor);
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void after_inserting_add_to_device_management();
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void before_will_be_destroyed_remove_from_device_management();
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virtual void after_inserting_add_symlink_to_device_identifier_directory() = 0;
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virtual void before_will_be_destroyed_remove_symlink_from_device_identifier_directory() = 0;
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// FIXME: These methods will be eventually removed after all nodes in /sys/dev/block/ and
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// /sys/dev/char/ are symlinks.
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virtual void after_inserting_add_to_device_identifier_directory() = 0;
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virtual void before_will_be_destroyed_remove_from_device_identifier_directory() = 0;
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private:
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MajorNumber const m_major { 0 };
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MinorNumber const m_minor { 0 };
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State m_state { State::Normal };
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Spinlock<LockRank::None> m_requests_lock {};
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DoublyLinkedList<LockRefPtr<AsyncDeviceRequest>> m_requests;
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protected:
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// FIXME: This pointer will be eventually removed after all nodes in /sys/dev/block/ and
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// /sys/dev/char/ are symlinks.
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RefPtr<SysFSDeviceComponent> m_sysfs_component;
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RefPtr<SysFSSymbolicLinkDeviceComponent> m_symlink_sysfs_component;
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RefPtr<SysFSDirectory> m_sysfs_device_directory;
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};
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}
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