Kernel: Steer away from heap allocations for ProcFS process data

Instead, use more static patterns to acquire that sort of data.

1 files changed, 119 insertions, 20 deletions

diff --git a/Kernel/FileSystem/ProcFS.h b/Kernel/FileSystem/ProcFS.h
index 9ffecfedf8..49b4d89b44 100644
--- a/Kernel/FileSystem/ProcFS.h
+++ b/Kernel/FileSystem/ProcFS.h
@@ -14,12 +14,17 @@
 #include <Kernel/KBufferBuilder.h>
 #include <Kernel/Locking/Mutex.h>
 #include <Kernel/ProcessExposed.h>
+#include <Kernel/UnixTypes.h>
 
 namespace Kernel {
 
 class ProcFS final : public FileSystem {
     friend class ProcFSInode;
     friend class ProcFSDirectoryInode;
+    friend class ProcFSProcessDirectoryInode;
+    friend class ProcFSGlobalInode;
+    friend class ProcFSAssociatedProcessInode;
+    friend class ProcFSProcessSubDirectoryInode;
 
 public:
     virtual ~ProcFS() override;
@@ -40,33 +45,50 @@ class ProcFSInode : public Inode {
     friend class ProcFS;
 
 public:
-    static NonnullRefPtr<ProcFSInode> create(const ProcFS&, const ProcFSExposedComponent&);
     virtual ~ProcFSInode() override;
+
+protected:
+    ProcFSInode(const ProcFS&, InodeIndex);
+
+    ProcFS& procfs() { return static_cast<ProcFS&>(Inode::fs()); }
+    ProcFS const& procfs() const { return static_cast<ProcFS const&>(Inode::fs()); }
+
+    // ^Inode
+    virtual KResult attach(FileDescription& description) = 0;
+    virtual void did_seek(FileDescription&, off_t) = 0;
+    virtual void flush_metadata() override final;
+    virtual KResultOr<NonnullRefPtr<Inode>> create_child(StringView name, mode_t, dev_t, uid_t, gid_t) override final;
+    virtual KResult add_child(Inode&, const StringView& name, mode_t) override final;
+    virtual KResult remove_child(const StringView& name) override final;
+    virtual KResult chmod(mode_t) override final;
+    virtual KResult chown(uid_t, gid_t) override final;
+    virtual KResult truncate(u64) override final;
+};
+
+class ProcFSGlobalInode : public ProcFSInode {
+    friend class ProcFS;
+
+public:
+    static NonnullRefPtr<ProcFSGlobalInode> create(const ProcFS&, const ProcFSExposedComponent&);
+    virtual ~ProcFSGlobalInode() override {};
     StringView name() const;
 
 protected:
-    ProcFSInode(const ProcFS&, const ProcFSExposedComponent&);
+    ProcFSGlobalInode(const ProcFS&, const ProcFSExposedComponent&);
 
     // ^Inode
-    virtual KResult attach(FileDescription& description) override;
-    virtual KResultOr<size_t> read_bytes(off_t, size_t, UserOrKernelBuffer& buffer, FileDescription*) const override;
-    virtual KResult traverse_as_directory(Function<bool(FileSystem::DirectoryEntryView const&)>) const override;
-    virtual RefPtr<Inode> lookup(StringView name) override;
-    virtual void flush_metadata() override;
+    virtual KResult attach(FileDescription& description) override final;
+    virtual KResultOr<size_t> read_bytes(off_t, size_t, UserOrKernelBuffer& buffer, FileDescription*) const override final;
+    virtual KResultOr<size_t> write_bytes(off_t, size_t, const UserOrKernelBuffer& buffer, FileDescription*) override final;
+    virtual void did_seek(FileDescription&, off_t) override final;
     virtual InodeMetadata metadata() const override;
-    virtual KResultOr<size_t> write_bytes(off_t, size_t, const UserOrKernelBuffer& buffer, FileDescription*) override;
-    virtual KResultOr<NonnullRefPtr<Inode>> create_child(StringView 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 void did_seek(FileDescription&, off_t) override;
-    virtual KResult chmod(mode_t) override;
-    virtual KResult chown(uid_t, gid_t) override;
-    virtual KResult truncate(u64) override;
+    virtual KResult traverse_as_directory(Function<bool(FileSystem::DirectoryEntryView const&)>) const override;
+    virtual RefPtr<Inode> lookup(StringView) override;
 
     NonnullRefPtr<ProcFSExposedComponent> m_associated_component;
 };
 
-class ProcFSLinkInode : public ProcFSInode {
+class ProcFSLinkInode : public ProcFSGlobalInode {
     friend class ProcFS;
 
 public:
@@ -77,16 +99,13 @@ protected:
     virtual InodeMetadata metadata() const override;
 };
 
-class ProcFSDirectoryInode : public ProcFSInode {
+class ProcFSDirectoryInode final : public ProcFSGlobalInode {
     friend class ProcFS;
 
 public:
     static NonnullRefPtr<ProcFSDirectoryInode> create(const ProcFS&, const ProcFSExposedComponent&);
     virtual ~ProcFSDirectoryInode() override;
 
-    ProcFS& fs() { return static_cast<ProcFS&>(Inode::fs()); }
-    ProcFS const& fs() const { return static_cast<ProcFS const&>(Inode::fs()); }
-
 protected:
     ProcFSDirectoryInode(const ProcFS&, const ProcFSExposedComponent&);
     // ^Inode
@@ -95,4 +114,84 @@ protected:
     virtual RefPtr<Inode> lookup(StringView name) override;
 };
 
+class ProcFSProcessAssociatedInode : public ProcFSInode {
+    friend class ProcFS;
+
+protected:
+    ProcFSProcessAssociatedInode(const ProcFS&, ProcessID, InodeIndex);
+    ProcessID associated_pid() const { return m_pid; }
+
+    // ^Inode
+    virtual KResultOr<size_t> write_bytes(off_t, size_t, const UserOrKernelBuffer& buffer, FileDescription*) override final;
+
+private:
+    const ProcessID m_pid;
+};
+
+class ProcFSProcessDirectoryInode final : public ProcFSProcessAssociatedInode {
+    friend class ProcFS;
+
+public:
+    static NonnullRefPtr<ProcFSProcessDirectoryInode> create(const ProcFS&, ProcessID);
+
+private:
+    ProcFSProcessDirectoryInode(const ProcFS&, ProcessID);
+    // ^Inode
+    virtual KResult attach(FileDescription& description) override;
+    virtual void did_seek(FileDescription&, off_t) override { }
+    virtual InodeMetadata metadata() const override;
+    virtual KResult traverse_as_directory(Function<bool(FileSystem::DirectoryEntryView const&)>) const override;
+    virtual KResultOr<size_t> read_bytes(off_t, size_t, UserOrKernelBuffer& buffer, FileDescription*) const override final;
+    virtual RefPtr<Inode> lookup(StringView name) override;
+};
+
+class ProcFSProcessSubDirectoryInode final : public ProcFSProcessAssociatedInode {
+    friend class ProcFS;
+
+public:
+    static NonnullRefPtr<ProcFSProcessSubDirectoryInode> create(const ProcFS&, SegmentedProcFSIndex::ProcessSubDirectory, ProcessID);
+
+private:
+    ProcFSProcessSubDirectoryInode(const ProcFS&, SegmentedProcFSIndex::ProcessSubDirectory, ProcessID);
+    // ^Inode
+    virtual KResult attach(FileDescription& description) override;
+    virtual void did_seek(FileDescription&, off_t) override;
+    virtual InodeMetadata metadata() const override;
+    virtual KResult traverse_as_directory(Function<bool(FileSystem::DirectoryEntryView const&)>) const override;
+    virtual KResultOr<size_t> read_bytes(off_t, size_t, UserOrKernelBuffer& buffer, FileDescription*) const override final;
+    virtual RefPtr<Inode> lookup(StringView name) override;
+
+    const SegmentedProcFSIndex::ProcessSubDirectory m_sub_directory_type;
+};
+
+class ProcFSProcessPropertyInode final : public ProcFSProcessAssociatedInode {
+    friend class ProcFS;
+
+public:
+    static NonnullRefPtr<ProcFSProcessPropertyInode> create_for_file_description_link(const ProcFS&, unsigned, ProcessID);
+    static NonnullRefPtr<ProcFSProcessPropertyInode> create_for_thread_stack(const ProcFS&, ThreadID, ProcessID);
+    static NonnullRefPtr<ProcFSProcessPropertyInode> create_for_pid_property(const ProcFS&, SegmentedProcFSIndex::MainProcessProperty, ProcessID);
+
+private:
+    ProcFSProcessPropertyInode(const ProcFS&, SegmentedProcFSIndex::MainProcessProperty, ProcessID);
+    ProcFSProcessPropertyInode(const ProcFS&, ThreadID, ProcessID);
+    ProcFSProcessPropertyInode(const ProcFS&, unsigned, ProcessID);
+    // ^Inode
+    virtual KResult attach(FileDescription& description) override;
+    virtual void did_seek(FileDescription&, off_t) override;
+    virtual InodeMetadata metadata() const override;
+    virtual KResult traverse_as_directory(Function<bool(FileSystem::DirectoryEntryView const&)>) const override;
+    virtual KResultOr<size_t> read_bytes(off_t, size_t, UserOrKernelBuffer& buffer, FileDescription*) const override final;
+    virtual RefPtr<Inode> lookup(StringView name) override final;
+
+    KResult refresh_data(FileDescription& description);
+    KResult try_to_acquire_data(Process& process, KBufferBuilder& builder) const;
+
+    const SegmentedProcFSIndex::ProcessSubDirectory m_parent_sub_directory_type;
+    union {
+        SegmentedProcFSIndex::MainProcessProperty property_type;
+        unsigned property_index;
+    } m_possible_data;
+    mutable Mutex m_refresh_lock;
+};
 }