ladybird/Kernel/Devices/Device.h
Liav A 25bb293629 Kernel: Make Device::after_inserting to return ErrorOr<void>
Instead of just returning nothing, let's return Error or nothing.
This would help later on with error propagation in case of failure
during this method.

This also makes us more paranoid about failure in this method, so when
initializing a DisplayConnector we safely tear down the internal members
of the object. This applies the same for a StorageDevice object, but its
after_inserting method is much smaller compared to the DisplayConnector
overriden method.
2023-01-07 11:45:08 -07:00

105 lines
3.6 KiB
C++

/*
* 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/Error.h>
#include <AK/Function.h>
#include <AK/HashMap.h>
#include <Kernel/Devices/AsyncDeviceRequest.h>
#include <Kernel/FileSystem/DeviceFileTypes.h>
#include <Kernel/FileSystem/File.h>
#include <Kernel/FileSystem/SysFS/Registry.h>
#include <Kernel/FileSystem/SysFS/Subsystems/DeviceIdentifiers/DeviceComponent.h>
#include <Kernel/FileSystem/SysFS/Subsystems/DeviceIdentifiers/SymbolicLinkDeviceComponent.h>
#include <Kernel/Library/LockRefPtr.h>
#include <Kernel/UnixTypes.h>
namespace Kernel {
class Device : public File {
protected:
enum class State {
Normal,
BeingRemoved,
};
public:
virtual ~Device() override;
MajorNumber major() const { return m_major; }
MinorNumber minor() const { return m_minor; }
virtual ErrorOr<NonnullOwnPtr<KString>> pseudo_path(OpenFileDescription const&) const override;
virtual ErrorOr<NonnullLockRefPtr<OpenFileDescription>> open(int options) override;
UserID uid() const { return m_uid; }
GroupID gid() const { return m_gid; }
virtual bool is_device() const override { return true; }
virtual void will_be_destroyed() override;
virtual ErrorOr<void> after_inserting();
virtual bool is_openable_by_jailed_processes() const { return false; }
void process_next_queued_request(Badge<AsyncDeviceRequest>, AsyncDeviceRequest const&);
template<typename AsyncRequestType, typename... Args>
ErrorOr<NonnullLockRefPtr<AsyncRequestType>> try_make_request(Args&&... args)
{
auto request = TRY(adopt_nonnull_lock_ref_or_enomem(new (nothrow) AsyncRequestType(*this, forward<Args>(args)...)));
SpinlockLocker lock(m_requests_lock);
bool was_empty = m_requests.is_empty();
TRY(m_requests.try_append(request));
if (was_empty)
request->do_start(move(lock));
return request;
}
protected:
Device(MajorNumber major, MinorNumber minor);
void set_uid(UserID uid) { m_uid = uid; }
void set_gid(GroupID gid) { m_gid = gid; }
void after_inserting_add_to_device_management();
void before_will_be_destroyed_remove_from_device_management();
virtual void after_inserting_add_symlink_to_device_identifier_directory() = 0;
virtual void before_will_be_destroyed_remove_symlink_from_device_identifier_directory() = 0;
// FIXME: These methods will be eventually removed after all nodes in /sys/dev/block/ and
// /sys/dev/char/ are symlinks.
virtual void after_inserting_add_to_device_identifier_directory() = 0;
virtual void before_will_be_destroyed_remove_from_device_identifier_directory() = 0;
private:
MajorNumber const m_major { 0 };
MinorNumber const m_minor { 0 };
UserID m_uid { 0 };
GroupID m_gid { 0 };
State m_state { State::Normal };
Spinlock<LockRank::None> m_requests_lock {};
DoublyLinkedList<LockRefPtr<AsyncDeviceRequest>> m_requests;
protected:
// FIXME: This pointer will be eventually removed after all nodes in /sys/dev/block/ and
// /sys/dev/char/ are symlinks.
LockRefPtr<SysFSDeviceComponent> m_sysfs_component;
LockRefPtr<SysFSSymbolicLinkDeviceComponent> m_symlink_sysfs_component;
LockRefPtr<SysFSDirectory> m_sysfs_device_directory;
};
}