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3af70cb0fc
It is starting to get a little messy with how each device can try to add or remove itself to either /sys/dev/block or /sys/dev/char directories. To better do this, we introduce 4 virtual methods to take care of that, so until we ensure all nodes in /sys/dev/block and /sys/dev/char are actual symlinks, we allow the Device base class to call virtual methods upon insertion or before being destroying, so it add itself elegantly to either of these directories or remove itself when needed. For special cases where we need to create symlinks, we have two virtual methods to be called otherwise to do almost the same thing mentioned before, but to use symlinks instead.
103 lines
3.4 KiB
C++
103 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 <AK/RefPtr.h>
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#include <Kernel/Devices/AsyncDeviceRequest.h>
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#include <Kernel/FileSystem/DeviceFileTypes.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/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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UserID uid() const { return m_uid; }
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GroupID gid() const { return m_gid; }
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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 void after_inserting();
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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<NonnullRefPtr<AsyncRequestType>> try_make_request(Args&&... args)
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{
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auto request = TRY(adopt_nonnull_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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m_requests.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 set_uid(UserID uid) { m_uid = uid; }
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void set_gid(GroupID gid) { m_gid = gid; }
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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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UserID m_uid { 0 };
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GroupID m_gid { 0 };
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State m_state { State::Normal };
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Spinlock m_requests_lock;
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DoublyLinkedList<RefPtr<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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