f5de4f24b2
Instead of doing so in the constructor, let's do immediately after the constructor, so we can safely pass a reference of a Device, so the SysFSDeviceComponent constructor can use that object to identify whether it's a block device or a character device. This allows to us to not hold a device in SysFSDeviceComponent with a RefPtr. Also, we also call the before_removing method in both SlavePTY::unref and File::unref, so because Device has that method being overrided, it can ensure the device is removed always cleanly.
98 lines
2.8 KiB
C++
98 lines
2.8 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/Function.h>
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#include <AK/HashMap.h>
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#include <AK/RefPtr.h>
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#include <Kernel/API/KResult.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.h>
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#include <Kernel/Locking/Mutex.h>
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#include <Kernel/UnixTypes.h>
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namespace Kernel {
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template<typename DeviceType, typename... Args>
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inline KResultOr<NonnullRefPtr<DeviceType>> try_create_device(Args&&... args)
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{
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auto device = TRY(adopt_nonnull_ref_or_enomem(new DeviceType(forward<Args>(args)...)));
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device->after_inserting();
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return device;
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}
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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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unsigned major() const { return m_major; }
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unsigned minor() const { return m_minor; }
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virtual String absolute_path(const OpenFileDescription&) const override;
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virtual String absolute_path() const;
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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 before_removing() override;
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virtual void after_inserting();
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static void for_each(Function<void(Device&)>);
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static Device* get_device(unsigned major, unsigned minor);
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void process_next_queued_request(Badge<AsyncDeviceRequest>, const AsyncDeviceRequest&);
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template<typename AsyncRequestType, typename... Args>
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KResultOr<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(unsigned major, unsigned 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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static MutexProtected<HashMap<u32, Device*>>& all_devices();
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private:
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unsigned m_major { 0 };
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unsigned 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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RefPtr<SysFSDeviceComponent> m_sysfs_component;
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};
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}
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