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https://github.com/RGBCube/serenity
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a6a439243f
This step would ideally not have been necessary (increases amount of refactoring and templates necessary, which in turn increases build times), but it gives us a couple of nice properties: - SpinlockProtected inside Singleton (a very common combination) can now obtain any lock rank just via the template parameter. It was not previously possible to do this with SingletonInstanceCreator magic. - SpinlockProtected's lock rank is now mandatory; this is the majority of cases and allows us to see where we're still missing proper ranks. - The type already informs us what lock rank a lock has, which aids code readability and (possibly, if gdb cooperates) lock mismatch debugging. - The rank of a lock can no longer be dynamic, which is not something we wanted in the first place (or made use of). Locks randomly changing their rank sounds like a disaster waiting to happen. - In some places, we might be able to statically check that locks are taken in the right order (with the right lock rank checking implementation) as rank information is fully statically known. This refactoring even more exposes the fact that Mutex has no lock rank capabilites, which is not fixed here.
105 lines
3.6 KiB
C++
105 lines
3.6 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/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/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<NonnullLockRefPtr<OpenFileDescription>> open(int options) 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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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 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<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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LockRefPtr<SysFSDeviceComponent> m_sysfs_component;
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LockRefPtr<SysFSSymbolicLinkDeviceComponent> m_symlink_sysfs_component;
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LockRefPtr<SysFSDirectory> m_sysfs_device_directory;
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};
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}
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