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Kernel: Rename DevFS => DevTmpFS

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The current implementation of DevFS resembles the linux devtmpfs, and
not the traditional DevFS, so let's rename it to better represent the
direction of the development in regard to this filesystem.

The abbreviation for DevTmpFS is still "dev", because it doesn't add
value as a commandline option to make it longer.

In quick summary - DevFS in unix OSes is simply a static filesystem, so
device nodes are generated and removed by the kernel code. DevTmpFS
is a "modern reinvention" of the DevFS, so it is much more like a TmpFS
in the sense that not only it's stored entirely in RAM, but the userland
is responsible to add and remove devices nodes as it sees fit, and no
kernel code is directly being involved to keep the filesystem in sync.
This commit is contained in:
Liav A 2021-08-14 16:28:09 +03:00 • committed by Andreas Kling
parent 750ca2190b
commit 3d5ddbab74
5 changed files with 110 additions and 108 deletions
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157
Kernel/FileSystem/DevFS.h
View file

@ -1,157 +0,0 @@
/*
* Copyright (c) 2020, Liav A. <liavalb@hotmail.co.il>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/Types.h>
#include <Kernel/FileSystem/FileSystem.h>
#include <Kernel/FileSystem/Inode.h>
#include <Kernel/FileSystem/InodeMetadata.h>
#include <Kernel/TTY/SlavePTY.h>
namespace Kernel {
class DevFS final : public FileSystem {
friend class DevFSInode;
friend class DevFSRootDirectoryInode;
public:
virtual ~DevFS() override;
static KResultOr<NonnullRefPtr<DevFS>> try_create();
virtual KResult initialize() override;
virtual StringView class_name() const override { return "DevFS"sv; }
virtual Inode& root_inode() override;
private:
DevFS();
size_t allocate_inode_index();
RefPtr<DevFSRootDirectoryInode> m_root_inode;
InodeIndex m_next_inode_index { 0 };
};
class DevFSInode : public Inode {
friend class DevFS;
friend class DevFSRootDirectoryInode;
friend class DevFSDirectoryInode;
public:
virtual StringView name() const = 0;
DevFS& fs() { return static_cast<DevFS&>(Inode::fs()); }
DevFS const& fs() const { return static_cast<DevFS const&>(Inode::fs()); }
protected:
DevFSInode(DevFS&);
virtual KResultOr<size_t> read_bytes(off_t, size_t, UserOrKernelBuffer& buffer, OpenFileDescription*) const override;
virtual KResult traverse_as_directory(Function<bool(FileSystem::DirectoryEntryView const&)>) const override;
virtual KResultOr<NonnullRefPtr<Inode>> lookup(StringView name) override;
virtual void flush_metadata() override;
virtual KResultOr<size_t> write_bytes(off_t, size_t, const UserOrKernelBuffer& buffer, OpenFileDescription*) override;
virtual KResultOr<NonnullRefPtr<Inode>> create_child(StringView name, mode_t, dev_t, UserID, GroupID) override;
virtual KResult add_child(Inode&, const StringView& name, mode_t) override;
virtual KResult remove_child(const StringView& name) override;
virtual KResult chmod(mode_t) override;
virtual KResult chown(UserID, GroupID) override;
virtual KResult truncate(u64) override;
private:
IntrusiveListNode<DevFSInode, RefPtr<DevFSInode>> m_list_node;
};
class DevFSDeviceInode : public DevFSInode {
friend class DevFS;
friend class DevFSRootDirectoryInode;
public:
virtual StringView name() const override;
virtual ~DevFSDeviceInode() override;
private:
DevFSDeviceInode(DevFS&, unsigned, unsigned, bool, NonnullOwnPtr<KString> name);
// ^Inode
virtual KResultOr<size_t> read_bytes(off_t, size_t, UserOrKernelBuffer& buffer, OpenFileDescription*) const override;
virtual InodeMetadata metadata() const override;
virtual KResultOr<size_t> write_bytes(off_t, size_t, const UserOrKernelBuffer& buffer, OpenFileDescription*) override;
virtual KResult chown(UserID, GroupID) override;
virtual KResult chmod(mode_t) override;
NonnullOwnPtr<KString> m_name;
const unsigned m_major_number;
const unsigned m_minor_number;
const bool m_block_device;
mode_t m_required_mode;
UserID m_uid { 0 };
GroupID m_gid { 0 };
};
class DevFSLinkInode : public DevFSInode {
friend class DevFS;
friend class DevFSRootDirectoryInode;
public:
virtual StringView name() const override;
virtual ~DevFSLinkInode() override;
protected:
DevFSLinkInode(DevFS&, NonnullOwnPtr<KString>);
// ^Inode
virtual KResultOr<size_t> read_bytes(off_t, size_t, UserOrKernelBuffer& buffer, OpenFileDescription*) const override;
virtual InodeMetadata metadata() const override;
virtual KResultOr<size_t> write_bytes(off_t, size_t, const UserOrKernelBuffer& buffer, OpenFileDescription*) override;
NonnullOwnPtr<KString> m_name;
OwnPtr<KString> m_link;
};
class DevFSDirectoryInode : public DevFSInode {
friend class DevFS;
friend class DevFSRootDirectoryInode;
public:
virtual ~DevFSDirectoryInode() override;
protected:
DevFSDirectoryInode(DevFS&);
// ^Inode
virtual InodeMetadata metadata() const override;
IntrusiveList<DevFSInode, NonnullRefPtr<DevFSInode>, &DevFSInode::m_list_node> m_nodes;
};
class DevFSPtsDirectoryInode final : public DevFSDirectoryInode {
friend class DevFS;
friend class DevFSRootDirectoryInode;
public:
virtual ~DevFSPtsDirectoryInode() override;
virtual StringView name() const override { return "pts"; };
private:
explicit DevFSPtsDirectoryInode(DevFS&);
virtual KResult traverse_as_directory(Function<bool(FileSystem::DirectoryEntryView const&)>) const override;
virtual KResultOr<NonnullRefPtr<Inode>> lookup(StringView name) override;
virtual InodeMetadata metadata() const override;
};
class DevFSRootDirectoryInode final : public DevFSDirectoryInode {
friend class DevFS;
public:
virtual ~DevFSRootDirectoryInode() override;
virtual StringView name() const override { return "."; }
private:
explicit DevFSRootDirectoryInode(DevFS&);
virtual KResultOr<NonnullRefPtr<Inode>> create_child(StringView name, mode_t, dev_t, UserID, GroupID) override;
virtual KResult traverse_as_directory(Function<bool(FileSystem::DirectoryEntryView const&)>) const override;
virtual KResultOr<NonnullRefPtr<Inode>> lookup(StringView name) override;
virtual InodeMetadata metadata() const override;
virtual KResult remove_child(const StringView& name) override;
};
}