ladybird/Kernel/FileSystem/AnonymousFile.h
Andreas Kling ab14b0ac64 Kernel: Hoist VM range allocation up to sys$mmap() itself
Instead of letting each File subclass do range allocation in their
mmap() override, do it up front in sys$mmap().

This makes us honor alignment requests for file-backed memory mappings
and simplifies the code somwhat.
2021-01-25 18:57:06 +01:00

57 lines
2.5 KiB
C++

/*
* Copyright (c) 2021, Andreas Kling <kling@serenityos.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#include <Kernel/FileSystem/File.h>
namespace Kernel {
class AnonymousFile final : public File {
public:
static NonnullRefPtr<AnonymousFile> create(NonnullRefPtr<AnonymousVMObject> vmobject)
{
return adopt(*new AnonymousFile(move(vmobject)));
}
virtual ~AnonymousFile() override;
virtual KResultOr<Region*> mmap(Process&, FileDescription&, const Range&, size_t offset, int prot, bool shared) override;
private:
virtual const char* class_name() const override { return "AnonymousFile"; }
virtual String absolute_path(const FileDescription&) const override { return ":anonymous-file:"; }
virtual bool can_read(const FileDescription&, size_t) const override { return false; }
virtual bool can_write(const FileDescription&, size_t) const override { return false; }
virtual KResultOr<size_t> read(FileDescription&, size_t, UserOrKernelBuffer&, size_t) override { return ENOTSUP; }
virtual KResultOr<size_t> write(FileDescription&, size_t, const UserOrKernelBuffer&, size_t) override { return ENOTSUP; }
explicit AnonymousFile(NonnullRefPtr<AnonymousVMObject>);
NonnullRefPtr<AnonymousVMObject> m_vmobject;
};
}