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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 <Kernel/Devices/AsyncDeviceRequest.h>
#include <Kernel/FileSystem/File.h>
#include <Kernel/Mutex.h>
#include <Kernel/UnixTypes.h>
namespace Kernel {
class Device : public File {
public:
virtual ~Device() override;
unsigned major() const { return m_major; }
unsigned minor() const { return m_minor; }
virtual String absolute_path(const FileDescription&) const override;
virtual String absolute_path() const;
uid_t uid() const { return m_uid; }
uid_t gid() const { return m_gid; }
virtual mode_t required_mode() const = 0;
virtual String device_name() const = 0;
virtual bool is_device() const override { return true; }
virtual bool is_disk_device() const { return false; }
static void for_each(Function<void(Device&)>);
static Device* get_device(unsigned major, unsigned minor);
void process_next_queued_request(Badge<AsyncDeviceRequest>, const AsyncDeviceRequest&);
template<typename AsyncRequestType, typename... Args>
NonnullRefPtr<AsyncRequestType> make_request(Args&&... args)
{
auto request = adopt_ref(*new AsyncRequestType(*this, forward<Args>(args)...));
ScopedSpinLock 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(uid_t uid) { m_uid = uid; }
void set_gid(gid_t gid) { m_gid = gid; }
static HashMap<u32, Device*>& all_devices();
private:
unsigned m_major { 0 };
unsigned m_minor { 0 };
uid_t m_uid { 0 };
gid_t m_gid { 0 };
SpinLock<u8> m_requests_lock;
DoublyLinkedList<RefPtr<AsyncDeviceRequest>> m_requests;
};
}
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