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Kernel: Introduce the DevFS

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The DevFS along with DevPtsFS give a complete solution for populating
device nodes in /dev. The main purpose of DevFS is to eliminate the
need of device nodes generation when building the system.

Later on, DevFS will assist with exposing disk partition nodes.
This commit is contained in:
Liav A 2020-12-25 19:26:38 +02:00 • committed by Andreas Kling
parent 18e77aa285
commit 247517cd4a
7 changed files with 774 additions and 55 deletions
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194
Kernel/FileSystem/DevFS.h Normal file
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/*
* Copyright (c) 2020, Liav A. <liavalb@hotmail.co.il>
* 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 <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 DevFSInode;
class DevFSDeviceInode;
class DevFSDirectoryInode;
class DevFSRootDirectoryInode;
class DevFSDevicesDirectoryInode;
class DevFSPtsDirectoryInode;
class Device;
class DevFS final : public FS {
friend class DevFSInode;
friend class DevFSRootDirectoryInode;
public:
virtual ~DevFS() override;
static NonnullRefPtr<DevFS> create();
virtual bool initialize() override;
virtual const char* class_name() const override { return "DevFS"; }
void notify_new_device(Device&);
void notify_device_removal(Device&);
virtual NonnullRefPtr<Inode> root_inode() const override;
private:
DevFS();
RefPtr<Inode> get_inode(InodeIdentifier) const;
size_t get_new_inode_index();
NonnullRefPtr<DevFSRootDirectoryInode> m_root_inode;
NonnullRefPtrVector<DevFSInode> m_nodes;
size_t m_inode_index { 0 };
};
class DevFSInode : public Inode {
friend class DevFS;
friend class DevFSRootDirectoryInode;
public:
virtual String name() const = 0;
protected:
DevFSInode(DevFS&);
virtual ssize_t read_bytes(off_t, ssize_t, UserOrKernelBuffer& buffer, FileDescription*) const override;
virtual KResult traverse_as_directory(Function<bool(const FS::DirectoryEntryView&)>) const override;
virtual RefPtr<Inode> lookup(StringView name) override;
virtual void flush_metadata() override;
virtual ssize_t write_bytes(off_t, ssize_t, const UserOrKernelBuffer& buffer, FileDescription*) override;
virtual KResultOr<NonnullRefPtr<Inode>> create_child(const String& name, mode_t, dev_t, uid_t, gid_t) override;
virtual KResult add_child(Inode&, const StringView& name, mode_t) override;
virtual KResult remove_child(const StringView& name) override;
virtual KResultOr<size_t> directory_entry_count() const override;
virtual KResult chmod(mode_t) override;
virtual KResult chown(uid_t, gid_t) override;
virtual KResult truncate(u64) override;
private:
size_t m_index;
};
class DevFSDeviceInode : public DevFSInode {
friend class DevFS;
friend class DevFSRootDirectoryInode;
public:
virtual String name() const override;
virtual ~DevFSDeviceInode() override;
private:
String determine_name() const;
DevFSDeviceInode(DevFS&, const Device&);
// ^Inode
virtual ssize_t read_bytes(off_t, ssize_t, UserOrKernelBuffer& buffer, FileDescription*) const override;
virtual InodeMetadata metadata() const override;
virtual ssize_t write_bytes(off_t, ssize_t, const UserOrKernelBuffer& buffer, FileDescription*) override;
virtual KResult chown(uid_t, gid_t) override;
NonnullRefPtr<Device> m_attached_device;
String m_cached_name;
uid_t m_uid { 0 };
gid_t m_gid { 0 };
};
class DevFSLinkInode : public DevFSInode {
friend class DevFS;
friend class DevFSRootDirectoryInode;
public:
virtual String name() const override;
virtual ~DevFSLinkInode() override;
protected:
DevFSLinkInode(DevFS&, String);
// ^Inode
virtual ssize_t read_bytes(off_t, ssize_t, UserOrKernelBuffer& buffer, FileDescription*) const override;
virtual InodeMetadata metadata() const override;
virtual ssize_t write_bytes(off_t, ssize_t, const UserOrKernelBuffer& buffer, FileDescription*) override;
const String m_name;
String 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;
virtual KResult traverse_as_directory(Function<bool(const FS::DirectoryEntryView&)>) const override;
virtual RefPtr<Inode> lookup(StringView name) override;
virtual KResultOr<size_t> directory_entry_count() const override;
NonnullRefPtrVector<DevFSDeviceInode> m_devices;
};
class DevFSPtsDirectoryInode final : public DevFSDirectoryInode {
friend class DevFS;
friend class DevFSRootDirectoryInode;
public:
virtual ~DevFSPtsDirectoryInode() override;
virtual String name() const override { return "pts"; };
private:
explicit DevFSPtsDirectoryInode(DevFS&);
virtual KResult traverse_as_directory(Function<bool(const FS::DirectoryEntryView&)>) const override;
virtual RefPtr<Inode> lookup(StringView name) override;
virtual InodeMetadata metadata() const override;
virtual KResultOr<size_t> directory_entry_count() const override;
};
class DevFSRootDirectoryInode final : public DevFSDirectoryInode {
friend class DevFS;
public:
virtual ~DevFSRootDirectoryInode() override;
virtual String name() const override { return "."; }
private:
explicit DevFSRootDirectoryInode(DevFS&);
virtual KResultOr<NonnullRefPtr<Inode>> create_child(const String& name, mode_t, dev_t, uid_t, gid_t) override;
virtual KResult traverse_as_directory(Function<bool(const FS::DirectoryEntryView&)>) const override;
virtual RefPtr<Inode> lookup(StringView name) override;
virtual InodeMetadata metadata() const override;
virtual KResultOr<size_t> directory_entry_count() const override;
NonnullRefPtrVector<DevFSDirectoryInode> m_subfolders;
NonnullRefPtrVector<DevFSLinkInode> m_links;
DevFS& m_parent_fs;
};
}