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/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
// Device is the base class of everything that lives in the /dev directory.
//
// To expose a Device to the filesystem, simply pass two unique numbers to the constructor,
// and then mknod a file in /dev with those numbers.
//
// There are two main subclasses:
// - BlockDevice (random access)
// - CharacterDevice (sequential)
#include <AK/DoublyLinkedList.h>
#include <AK/Function.h>
#include <AK/HashMap.h>
#include <AK/RefPtr.h>
#include <Kernel/API/KResult.h>
#include <Kernel/Devices/AsyncDeviceRequest.h>
#include <Kernel/FileSystem/File.h>
#include <Kernel/FileSystem/SysFS.h>
#include <Kernel/Locking/Mutex.h>
#include <Kernel/UnixTypes.h>
namespace Kernel {
class Device : public File {
protected:
enum class State {
Normal,
BeingRemoved,
};
public:
virtual ~Device() override;
unsigned major() const { return m_major; }
unsigned minor() const { return m_minor; }
virtual String absolute_path(const OpenFileDescription&) const override;
virtual String absolute_path() const;
UserID uid() const { return m_uid; }
GroupID gid() const { return m_gid; }
virtual bool is_device() const override { return true; }
virtual void before_removing() override;
virtual void after_inserting();
void process_next_queued_request(Badge<AsyncDeviceRequest>, const AsyncDeviceRequest&);
template<typename AsyncRequestType, typename... Args>
KResultOr<NonnullRefPtr<AsyncRequestType>> try_make_request(Args&&... args)
{
auto request = TRY(adopt_nonnull_ref_or_enomem(new (nothrow) AsyncRequestType(*this, forward<Args>(args)...)));
SpinlockLocker lock(m_requests_lock);
bool was_empty = m_requests.is_empty();
m_requests.append(request);
if (was_empty)
request->do_start(move(lock));
return request;
}
protected:
Device(unsigned major, unsigned minor);
void set_uid(UserID uid) { m_uid = uid; }
void set_gid(GroupID gid) { m_gid = gid; }
private:
unsigned m_major { 0 };
unsigned m_minor { 0 };
UserID m_uid { 0 };
GroupID m_gid { 0 };
State m_state { State::Normal };
Spinlock m_requests_lock;
DoublyLinkedList<RefPtr<AsyncDeviceRequest>> m_requests;
RefPtr<SysFSDeviceComponent> m_sysfs_component;
};
}
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