ladybird/Kernel/ProcessExposed.h
MacDue d951e2ca97 Kernel: Add /proc/{pid}/children to ProcFS
This exposes the child processes for a process as a directory
of symlinks to the respective /proc entries for each child.

This makes for an easier and possibly more efficient way
to find and count a process's children. Previously the only
method was to parse the entire /proc/all JSON file.
2022-05-06 02:12:51 +04:30

208 lines
6.9 KiB
C++

/*
* Copyright (c) 2021, Liav A. <liavalb@hotmail.co.il>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/Error.h>
#include <AK/Function.h>
#include <AK/RefCounted.h>
#include <AK/RefPtr.h>
#include <AK/Types.h>
#include <Kernel/FileSystem/File.h>
#include <Kernel/FileSystem/FileSystem.h>
#include <Kernel/FileSystem/OpenFileDescription.h>
#include <Kernel/KBufferBuilder.h>
#include <Kernel/Time/TimeManagement.h>
#include <Kernel/UserOrKernelBuffer.h>
namespace Kernel {
namespace SegmentedProcFSIndex {
enum class MainProcessProperty {
Reserved = 0,
Unveil = 1,
Pledge = 2,
OpenFileDescriptions = 3,
BinaryLink = 4,
CurrentWorkDirectoryLink = 5,
PerformanceEvents = 6,
VirtualMemoryStats = 7,
};
enum class ProcessSubDirectory {
Reserved = 0,
OpenFileDescriptions = 1,
Stacks = 2,
Children = 3
};
void read_segments(u32& primary, ProcessSubDirectory& sub_directory, MainProcessProperty& property);
InodeIndex build_segmented_index_for_pid_directory(ProcessID);
InodeIndex build_segmented_index_for_sub_directory(ProcessID, ProcessSubDirectory sub_directory);
InodeIndex build_segmented_index_for_main_property(ProcessID, ProcessSubDirectory sub_directory, MainProcessProperty property);
InodeIndex build_segmented_index_for_main_property_in_pid_directory(ProcessID, MainProcessProperty property);
InodeIndex build_segmented_index_for_thread_stack(ProcessID, ThreadID);
InodeIndex build_segmented_index_for_file_description(ProcessID, unsigned);
InodeIndex build_segmented_index_for_children(ProcessID, ProcessID);
}
class ProcFSComponentRegistry {
public:
static ProcFSComponentRegistry& the();
static void initialize();
ProcFSComponentRegistry();
ProcFSRootDirectory& root_directory() { return *m_root_directory; }
Mutex& get_lock() { return m_lock; }
private:
Mutex m_lock;
NonnullRefPtr<ProcFSRootDirectory> m_root_directory;
};
class ProcFSExposedComponent : public RefCounted<ProcFSExposedComponent> {
public:
StringView name() const { return m_name->view(); }
virtual ErrorOr<size_t> read_bytes(off_t, size_t, UserOrKernelBuffer&, OpenFileDescription*) const { VERIFY_NOT_REACHED(); }
virtual ErrorOr<void> traverse_as_directory(FileSystemID, Function<ErrorOr<void>(FileSystem::DirectoryEntryView const&)>) const { VERIFY_NOT_REACHED(); }
virtual ErrorOr<NonnullRefPtr<ProcFSExposedComponent>> lookup(StringView) { VERIFY_NOT_REACHED(); };
virtual ErrorOr<size_t> write_bytes(off_t, size_t, UserOrKernelBuffer const&, OpenFileDescription*) { return EROFS; }
virtual ErrorOr<void> truncate(u64) { return EPERM; }
virtual ErrorOr<void> set_mtime(time_t) { return ENOTIMPL; }
virtual mode_t required_mode() const { return 0444; }
virtual UserID owner_user() const { return 0; }
virtual GroupID owner_group() const { return 0; }
static time_t modified_time() { return TimeManagement::now().to_timeval().tv_sec; }
virtual void prepare_for_deletion() { }
virtual ErrorOr<void> refresh_data(OpenFileDescription&) const
{
return {};
}
virtual ErrorOr<NonnullRefPtr<Inode>> to_inode(ProcFS const& procfs_instance) const;
virtual InodeIndex component_index() const { return m_component_index; }
virtual ~ProcFSExposedComponent() = default;
protected:
ProcFSExposedComponent();
explicit ProcFSExposedComponent(StringView name);
private:
OwnPtr<KString> m_name;
InodeIndex m_component_index {};
};
class ProcFSExposedDirectory
: public ProcFSExposedComponent
, public Weakable<ProcFSExposedDirectory> {
friend class ProcFSComponentRegistry;
public:
virtual ErrorOr<void> traverse_as_directory(FileSystemID, Function<ErrorOr<void>(FileSystem::DirectoryEntryView const&)>) const override;
virtual ErrorOr<NonnullRefPtr<ProcFSExposedComponent>> lookup(StringView name) override;
void add_component(ProcFSExposedComponent const&);
virtual void prepare_for_deletion() override
{
for (auto& component : m_components) {
component.prepare_for_deletion();
}
}
virtual mode_t required_mode() const override { return 0555; }
virtual ErrorOr<NonnullRefPtr<Inode>> to_inode(ProcFS const& procfs_instance) const override final;
protected:
explicit ProcFSExposedDirectory(StringView name);
ProcFSExposedDirectory(StringView name, ProcFSExposedDirectory const& parent_directory);
NonnullRefPtrVector<ProcFSExposedComponent> m_components;
WeakPtr<ProcFSExposedDirectory> m_parent_directory;
};
class ProcFSExposedLink : public ProcFSExposedComponent {
public:
virtual ErrorOr<NonnullRefPtr<Inode>> to_inode(ProcFS const& procfs_instance) const override final;
virtual ErrorOr<size_t> read_bytes(off_t offset, size_t count, UserOrKernelBuffer& buffer, OpenFileDescription* description) const override;
protected:
virtual bool acquire_link(KBufferBuilder& builder) = 0;
explicit ProcFSExposedLink(StringView name);
mutable Mutex m_lock { "ProcFSLink" };
};
namespace PCI {
class Access;
}
class ProcFSRootDirectory final : public ProcFSExposedDirectory {
friend class ProcFSComponentRegistry;
public:
virtual ErrorOr<NonnullRefPtr<ProcFSExposedComponent>> lookup(StringView name) override;
static NonnullRefPtr<ProcFSRootDirectory> must_create();
void add_pci_node(Badge<PCI::Access>);
virtual ~ProcFSRootDirectory();
private:
virtual ErrorOr<void> traverse_as_directory(FileSystemID, Function<ErrorOr<void>(FileSystem::DirectoryEntryView const&)>) const override;
ProcFSRootDirectory();
};
struct ProcFSInodeData : public OpenFileDescriptionData {
OwnPtr<KBuffer> buffer;
};
class ProcFSGlobalInformation : public ProcFSExposedComponent {
public:
virtual ~ProcFSGlobalInformation() override {};
virtual ErrorOr<size_t> read_bytes(off_t offset, size_t count, UserOrKernelBuffer& buffer, OpenFileDescription* description) const override;
virtual mode_t required_mode() const override { return 0444; }
protected:
explicit ProcFSGlobalInformation(StringView name)
: ProcFSExposedComponent(name)
{
}
virtual ErrorOr<void> refresh_data(OpenFileDescription&) const override;
virtual ErrorOr<void> try_generate(KBufferBuilder&) = 0;
mutable Mutex m_refresh_lock;
};
class ProcFSSystemBoolean : public ProcFSGlobalInformation {
public:
virtual bool value() const = 0;
virtual void set_value(bool new_value) = 0;
protected:
explicit ProcFSSystemBoolean(StringView name)
: ProcFSGlobalInformation(name)
{
}
private:
// ^ProcFSGlobalInformation
virtual ErrorOr<void> try_generate(KBufferBuilder&) override final;
// ^ProcFSExposedComponent
virtual ErrorOr<size_t> write_bytes(off_t, size_t, UserOrKernelBuffer const&, OpenFileDescription*) override final;
virtual mode_t required_mode() const override final { return 0644; }
virtual ErrorOr<void> truncate(u64) override final;
virtual ErrorOr<void> set_mtime(time_t) override final;
};
}