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009feefee0
Devices might be removed and inserted at anytime, so let's ensure we always do these kind of operations with a good known state of the HashMap. The VirtIO code was modified to create devices outside the IRQ handler, so now it works with the new locking of the devices singleton, but a better approach might be needed later on.
77 lines
2.3 KiB
C++
77 lines
2.3 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 <Kernel/Devices/AsyncDeviceRequest.h>
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#include <Kernel/FileSystem/File.h>
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#include <Kernel/FileSystem/SysFSComponent.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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class Device : public File {
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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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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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Spinlock m_requests_lock;
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DoublyLinkedList<RefPtr<AsyncDeviceRequest>> m_requests;
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};
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}
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