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Kernel/FileSystem: Simplify the ProcFS significantly

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Since the ProcFS doesn't hold many global objects within it, the need
for a fully-structured design of backing components and a registry like
with the SysFS is no longer true.

To acommodate this, let's remove all backing store and components of the
ProcFS, so now it resembles what we had in the early days of ProcFS in
the project - a mostly-static filesystem, with very small amount of
kmalloc allocations needed.
We still use the inode index mechanism to understand the role of each
inode, but this is done in a much "static"ier way than before.
This commit is contained in:
Liav A 2023-02-20 17:51:18 +02:00 • committed by Linus Groh
parent 9216caeec2
commit c56e1c5378
18 changed files with 362 additions and 952 deletions
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85
Kernel/FileSystem/ProcFS/Inode.h
View file

@ -1,5 +1,6 @@
/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* Copyright (c) 2022-2023, Liav A. <liavalb@hotmail.co.il>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
@ -8,95 +9,73 @@
#include <Kernel/FileSystem/Inode.h>
#include <Kernel/FileSystem/OpenFileDescription.h>
#include <Kernel/FileSystem/ProcFS/Definitions.h>
#include <Kernel/FileSystem/ProcFS/FileSystem.h>
#include <Kernel/ProcessExposed.h>
#include <Kernel/KBufferBuilder.h>
#include <Kernel/UnixTypes.h>
namespace Kernel {
struct ProcFSInodeData : public OpenFileDescriptionData {
OwnPtr<KBuffer> buffer;
};
class ProcFSExposedDirectory;
class ProcFSExposedLink;
class ProcFSInode final : public Inode {
friend class ProcFS;
public:
enum class Type {
GlobalLink,
GlobalDirectory,
FileDescriptionLink,
ThreadStack,
RootDirectory,
SelfProcessLink,
ProcessProperty,
ChildProcessLink,
ProcessDirectory,
ProcessSubdirectory,
};
static ErrorOr<NonnullLockRefPtr<ProcFSInode>> try_create_as_file_description_link_inode(ProcFS const&, unsigned, ProcessID);
static ErrorOr<NonnullLockRefPtr<ProcFSInode>> try_create_as_thread_stack_inode(ProcFS const&, ThreadID, ProcessID);
static ErrorOr<NonnullLockRefPtr<ProcFSInode>> try_create_as_pid_property_inode(ProcFS const&, SegmentedProcFSIndex::MainProcessProperty, ProcessID);
static ErrorOr<NonnullLockRefPtr<ProcFSInode>> try_create_as_child_process_link_inode(ProcFS const&, ProcessID, ProcessID);
static ErrorOr<NonnullLockRefPtr<ProcFSInode>> try_create_as_process_directory_inode(ProcFS const&, ProcessID);
static ErrorOr<NonnullLockRefPtr<ProcFSInode>> try_create_as_process_subdirectory_inode(ProcFS const&, SegmentedProcFSIndex::ProcessSubDirectory, ProcessID);
static ErrorOr<NonnullLockRefPtr<ProcFSInode>> try_create_as_directory_inode(ProcFS const&, ProcFSExposedDirectory const&);
static ErrorOr<NonnullLockRefPtr<ProcFSInode>> try_create_as_global_link_inode(ProcFS const&, ProcFSExposedLink const&);
static InodeIndex create_index_from_global_directory_entry(segmented_global_inode_index entry);
static InodeIndex create_index_from_process_directory_entry(ProcessID pid, segmented_process_directory_entry entry);
virtual ~ProcFSInode() override;
private:
// ProcFS PID property inode (/proc/PID/PROPERTY)
ProcFSInode(ProcFS const&, SegmentedProcFSIndex::MainProcessProperty, ProcessID);
// ProcFS Thread stack inode (/proc/PID/stacks/TID)
ProcFSInode(ProcFS const&, ThreadID, ProcessID);
// ProcFS File description link inode (/proc/PID/fd/FD)
ProcFSInode(ProcFS const&, unsigned, ProcessID);
// ProcFS Child process link inode (/proc/PID/children/CHILD_PID)
ProcFSInode(ProcFS const&, ProcessID, ProcessID);
// ProcFS Process directory inode (/proc/PID/)
ProcFSInode(ProcFS const&, ProcessID);
// ProcFS Process sub directory inode (/proc/PID/SUBDIRECTORY)
ProcFSInode(ProcFS const&, SegmentedProcFSIndex::ProcessSubDirectory, ProcessID);
ProcFSInode(ProcFS const&, ProcFSExposedLink const&);
ProcFSInode(ProcFS const&, ProcFSExposedDirectory const&);
ProcFSInode(ProcFS const&, InodeIndex);
ProcFS& procfs() { return static_cast<ProcFS&>(Inode::fs()); }
ProcFS const& procfs() const { return static_cast<ProcFS const&>(Inode::fs()); }
// ^Inode (EROFS handling)
virtual ErrorOr<NonnullLockRefPtr<Inode>> create_child(StringView, mode_t, dev_t, UserID, GroupID) override { return EROFS; }
virtual ErrorOr<void> add_child(Inode&, StringView, mode_t) override { return EROFS; }
virtual ErrorOr<void> remove_child(StringView) override { return EROFS; }
virtual ErrorOr<void> replace_child(StringView, Inode&) override { return EROFS; }
virtual ErrorOr<void> chmod(mode_t) override { return EROFS; }
virtual ErrorOr<void> chown(UserID, GroupID) override { return EROFS; }
virtual ErrorOr<size_t> write_bytes_locked(off_t, size_t, UserOrKernelBuffer const&, OpenFileDescription*) override { return EROFS; }
virtual ErrorOr<void> truncate(u64) override { return EROFS; }
// ^Inode (Silent ignore handling)
virtual ErrorOr<void> flush_metadata() override { return {}; }
virtual ErrorOr<void> update_timestamps(Optional<Time>, Optional<Time>, Optional<Time>) override { return {}; }
// ^Inode
virtual ErrorOr<void> attach(OpenFileDescription& description) override;
virtual void did_seek(OpenFileDescription&, off_t) override;
virtual ErrorOr<void> flush_metadata() override final;
virtual ErrorOr<NonnullLockRefPtr<Inode>> create_child(StringView name, mode_t, dev_t, UserID, GroupID) override;
virtual ErrorOr<void> add_child(Inode&, StringView name, mode_t) override final;
virtual ErrorOr<void> remove_child(StringView name) override final;
virtual ErrorOr<void> replace_child(StringView name, Inode& child) override final;
virtual ErrorOr<void> chmod(mode_t) override final;
virtual ErrorOr<void> chown(UserID, GroupID) override final;
virtual InodeMetadata metadata() const override;
ErrorOr<void> traverse_as_root_directory(Function<ErrorOr<void>(FileSystem::DirectoryEntryView const&)>) const;
virtual ErrorOr<void> traverse_as_directory(Function<ErrorOr<void>(FileSystem::DirectoryEntryView const&)>) const override;
virtual InodeMetadata metadata() const override;
virtual ErrorOr<size_t> read_bytes_locked(off_t, size_t, UserOrKernelBuffer& buffer, OpenFileDescription*) const override;
virtual ErrorOr<size_t> write_bytes_locked(off_t, size_t, UserOrKernelBuffer const& buffer, OpenFileDescription*) override;
ErrorOr<NonnullLockRefPtr<Inode>> lookup_as_root_directory(StringView name);
virtual ErrorOr<NonnullLockRefPtr<Inode>> lookup(StringView name) override final;
virtual ErrorOr<void> truncate(u64) override final;
virtual ErrorOr<void> update_timestamps(Optional<Time> atime, Optional<Time> ctime, Optional<Time> mtime) override;
ErrorOr<void> refresh_process_property_data(OpenFileDescription& description);
ErrorOr<void> try_fetch_process_property_data(NonnullLockRefPtr<Process>, KBufferBuilder& builder) const;
Type m_type;
union {
SegmentedProcFSIndex::MainProcessProperty property_type;
unsigned property_index;
} m_possible_data;
Optional<SegmentedProcFSIndex::ProcessSubDirectory> const m_parent_subdirectory_type {};
Optional<SegmentedProcFSIndex::ProcessSubDirectory> const m_subdirectory_type {};
Optional<ProcessID> const m_associated_pid {};
u16 const m_subdirectory { 0 };
u32 const m_property { 0 };
LockRefPtr<ProcFSExposedComponent> m_associated_component;
mutable Mutex m_refresh_lock;
};