Kernel+SystemServer+Base: Introduce the RAMFS filesystem

This filesystem is based on the code of the long-lived TmpFS. It differs
from that filesystem in one keypoint - its root inode doesn't have a
sticky bit on it.

Therefore, we mount it on /dev, to ensure only root can modify files on
that directory. In addition to that, /tmp is mounted directly in the
SystemServer main (start) code, so it's no longer specified in the fstab
file. We ensure that /tmp has a sticky bit and has the value 0777 for
root directory permissions, which is certainly a special case when using
RAM-backed (and in general other) filesystems.

Because of these 2 changes, it's no longer needed to maintain the TmpFS
filesystem, hence it's removed (renamed to RAMFS), because the RAMFS
represents the purpose of this filesystem in a much better way - it
relies on being backed by RAM "storage", and therefore it's easy to
conclude it's temporary and volatile, so its content is gone on either
system shutdown or unmounting of the filesystem.

Base/etc/fstab

@@ -11,4 +11,3 @@
 /usr/Tests	/usr/Tests	bind	bind,nodev,ro
 /usr/local	/usr/local	bind	bind,nodev,nosuid
 
-none	/tmp	tmp	nodev,nosuid

Base/usr/share/man/man2/mount.md

@@ -20,7 +20,7 @@ over `target`.
 * `Ext2FS` (or `ext2`): The ext2 filesystem.
 * `ProcFS` (or `proc`): The process pseudo-filesystem (normally mounted at `/proc`).
 * `DevPtsFS` (or `devpts`): The pseudoterminal pseudo-filesystem (normally mounted at `/dev/pts`).
-* `TmpFS` (or `tmp`): A non-persistent filesystem that stores all its data in RAM. An instance of this filesystem is normally mounted at `/tmp`.
+* `RAMFS` (or `ram`): A non-persistent filesystem that stores all its data in RAM. An instance of this filesystem is normally mounted at `/tmp`.
 * `Plan9FS` (or `9p`): A remote filesystem served over the 9P protocol.
 
 For Ext2FS, `source_fd` must refer to an open file descriptor to a file

Documentation/Kernel/RAMFS.md

@@ -1,16 +1,16 @@
-# `TmpFS` filesystem and its purposes
+# `RAMFS` filesystem and its purposes
 
-`TmpFS` is a RAM-backed filesystem. It is used to hold files and directories in the `/tmp` directory and
+`RAMFS` is a RAM-backed filesystem. It is used to hold files and directories in the `/tmp` directory and
 device nodes in the `/dev` directory.
 
-## What are the `TmpFS` filesystem characteristics?
+## What are the `RAMFS` filesystem characteristics?
 
-`TmpFS` is a pure RAM-backed filesystem, which means all files and directories
+`RAMFS` is a pure RAM-backed filesystem, which means all files and directories
-actually live in memory, each in its own `TmpFS` instance in the kernel.
+actually live in memory, each in its own `RAMFS` instance in the kernel.
 
-The `TmpFS` in its current design is very conservative about allocating virtual memory ranges
+The `RAMFS` in its current design is very conservative about allocating virtual memory ranges
 for itself, and instead it uses the `AnonymousVMObject` object to hold physical pages containing
-data for its inodes. When doing actual IO, the `TmpFS` code temporarily allocates a small virtual memory
+data for its inodes. When doing actual IO, the `RAMFS` code temporarily allocates a small virtual memory
 `Memory::Region` to perform the task, which works quite well although it puts a strain on the virtual memory
 mapping code. The current design also ensures that fabricated huge files can be easily created in the filesystem
 with very small overhead until actual IO is performed.
@@ -24,10 +24,10 @@ Many test suites in the project leverage the `/tmp` for placing their test files
 when trying to check the correctness of many system-related functionality.
 Other programs rely on `/tmp` for placing their temporary files to properly function.
 
-### Why does the `TmpFS` work well for the `/dev` directory?
+### Why does the `RAMFS` work well for the `/dev` directory?
 
-To understand why `TmpFS` works reliably when mounted on `/dev`, we must understand
+To understand why `RAMFS` works reliably when mounted on `/dev`, we must understand
-first what we did in the past and how `TmpFS` solves many of the issues with the previous design.
+first what we did in the past and how `RAMFS` solves many of the issues with the previous design.
 
 At first, we didn't have any special filesystem mounted in `/dev` as the image build 
 script generated all the required device nodes in `/dev`. This was quite sufficient in
@@ -54,7 +54,7 @@ The `DevFS` solution was short-lived, and was quickly replaced by the `DevTmpFS`
 That new shiny filesystem was again specific to `/dev`, but it solved many of the issues
 `DevFS` suffered from - no more hardcoded permissions and now the design has flexible filesystem
 layout in its mindset.
-This was achieved by implementing from scratch a filesystem that resembles the `TmpFS`
+This was achieved by implementing from scratch a filesystem that resembles the `RAMFS`
 filesystem, but was different in one major aspect - only device nodes and directories are allowed
 to be in `/dev`. This strict requirement has been mandated to ensure the user doesn't
 accidentally put unrelated files in `/dev`. When the `DevTmpFS` was invented, it clearly
@@ -65,6 +65,6 @@ in this document, but ultimately evolved to be flexible enough to work quite wel
 Everything worked quite well, but there was still a prominent problem with `DevTmpFS` -
 it was an entire filesystem solution just for `/dev` and nobody else used it.
 Testing the filesystem was quite clunky and truthfully lacking from the beginning until its removal.
-To solve this problem, it was decided to stop using it, and instead just use `TmpFS`.
+To solve this problem, it was decided to stop using it, and instead just use `RAMFS`.
 To ensure the current behavior of disallowing regular files in `/dev`, a new mount flag called
 `MS_NOREGULAR` was invented, so it could be mounted with it.

Kernel/CMakeLists.txt

@@ -135,6 +135,8 @@ set(KERNEL_SOURCES
     FileSystem/ProcFS/ComponentRegistry.cpp
     FileSystem/ProcFS/FileSystem.cpp
     FileSystem/ProcFS/Inode.cpp
+    FileSystem/RAMFS/FileSystem.cpp
+    FileSystem/RAMFS/Inode.cpp
     FileSystem/SysFS/Component.cpp
     FileSystem/SysFS/DirectoryInode.cpp
     FileSystem/SysFS/FileSystem.cpp
@@ -196,8 +198,6 @@ set(KERNEL_SOURCES
     FileSystem/SysFS/Subsystems/Kernel/Variables/DumpKmallocStack.cpp
     FileSystem/SysFS/Subsystems/Kernel/Variables/StringVariable.cpp
     FileSystem/SysFS/Subsystems/Kernel/Variables/UBSANDeadly.cpp
-    FileSystem/TmpFS/FileSystem.cpp
-    FileSystem/TmpFS/Inode.cpp
     FileSystem/VirtualFileSystem.cpp
     Firmware/BIOS.cpp
     Firmware/ACPI/Initialize.cpp

Kernel/FileSystem/RAMFS/FileSystem.cpp

@@ -0,0 +1,40 @@
+/*
+ * Copyright (c) 2019-2020, Sergey Bugaev <bugaevc@serenityos.org>
+ * Copyright (c) 2022-2023, Liav A. <liavalb@hotmail.co.il>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <Kernel/FileSystem/RAMFS/FileSystem.h>
+#include <Kernel/FileSystem/RAMFS/Inode.h>
+
+namespace Kernel {
+
+ErrorOr<NonnullLockRefPtr<FileSystem>> RAMFS::try_create()
+{
+    return TRY(adopt_nonnull_lock_ref_or_enomem(new (nothrow) RAMFS));
+}
+
+RAMFS::RAMFS() = default;
+RAMFS::~RAMFS() = default;
+
+ErrorOr<void> RAMFS::initialize()
+{
+    m_root_inode = TRY(RAMFSInode::try_create_root(*this));
+    return {};
+}
+
+Inode& RAMFS::root_inode()
+{
+    VERIFY(!m_root_inode.is_null());
+    return *m_root_inode;
+}
+
+unsigned RAMFS::next_inode_index()
+{
+    MutexLocker locker(m_lock);
+
+    return m_next_inode_index++;
+}
+
+}

Kernel/FileSystem/RAMFS/FileSystem.h

@@ -1,6 +1,6 @@
 /*
  * Copyright (c) 2019-2020, Sergey Bugaev <bugaevc@serenityos.org>
- * Copyright (c) 2022, Liav A. <liavalb@hotmail.co.il>
+ * Copyright (c) 2022-2023, Liav A. <liavalb@hotmail.co.il>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -13,24 +13,24 @@
 
 namespace Kernel {
 
-class TmpFS final : public FileSystem {
+class RAMFS final : public FileSystem {
-    friend class TmpFSInode;
+    friend class RAMFSInode;
 
 public:
-    virtual ~TmpFS() override;
+    virtual ~RAMFS() override;
     static ErrorOr<NonnullLockRefPtr<FileSystem>> try_create();
     virtual ErrorOr<void> initialize() override;
 
-    virtual StringView class_name() const override { return "TmpFS"sv; }
+    virtual StringView class_name() const override { return "RAMFS"sv; }
 
     virtual bool supports_watchers() const override { return true; }
 
     virtual Inode& root_inode() override;
 
 private:
-    TmpFS();
+    RAMFS();
 
-    LockRefPtr<TmpFSInode> m_root_inode;
+    LockRefPtr<RAMFSInode> m_root_inode;
 
     // NOTE: We start by assigning InodeIndex of 2, because 0 is invalid and 1
     // is reserved for the root directory inode.

Kernel/FileSystem/RAMFS/Inode.cpp

@@ -1,16 +1,16 @@
 /*
  * Copyright (c) 2019-2020, Sergey Bugaev <bugaevc@serenityos.org>
- * Copyright (c) 2022, Liav A. <liavalb@hotmail.co.il>
+ * Copyright (c) 2022-2023, Liav A. <liavalb@hotmail.co.il>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
-#include <Kernel/FileSystem/TmpFS/Inode.h>
+#include <Kernel/FileSystem/RAMFS/Inode.h>
 #include <Kernel/Process.h>
 
 namespace Kernel {
 
-TmpFSInode::TmpFSInode(TmpFS& fs, InodeMetadata const& metadata, LockWeakPtr<TmpFSInode> parent)
+RAMFSInode::RAMFSInode(RAMFS& fs, InodeMetadata const& metadata, LockWeakPtr<RAMFSInode> parent)
     : Inode(fs, fs.next_inode_index())
     , m_metadata(metadata)
     , m_parent(move(parent))
@@ -18,7 +18,7 @@ TmpFSInode::TmpFSInode(TmpFS& fs, InodeMetadata const& metadata, LockWeakPtr<Tmp
     m_metadata.inode = identifier();
 }
 
-TmpFSInode::TmpFSInode(TmpFS& fs)
+RAMFSInode::RAMFSInode(RAMFS& fs)
     : Inode(fs, 1)
     , m_root_directory_inode(true)
 {
@@ -27,29 +27,29 @@ TmpFSInode::TmpFSInode(TmpFS& fs)
     m_metadata.atime = now;
     m_metadata.ctime = now;
     m_metadata.mtime = now;
-    m_metadata.mode = S_IFDIR | S_ISVTX | 0777;
+    m_metadata.mode = S_IFDIR | 0755;
 }
 
-TmpFSInode::~TmpFSInode() = default;
+RAMFSInode::~RAMFSInode() = default;
 
-ErrorOr<NonnullLockRefPtr<TmpFSInode>> TmpFSInode::try_create(TmpFS& fs, InodeMetadata const& metadata, LockWeakPtr<TmpFSInode> parent)
+ErrorOr<NonnullLockRefPtr<RAMFSInode>> RAMFSInode::try_create(RAMFS& fs, InodeMetadata const& metadata, LockWeakPtr<RAMFSInode> parent)
 {
-    return adopt_nonnull_lock_ref_or_enomem(new (nothrow) TmpFSInode(fs, metadata, move(parent)));
+    return adopt_nonnull_lock_ref_or_enomem(new (nothrow) RAMFSInode(fs, metadata, move(parent)));
 }
 
-ErrorOr<NonnullLockRefPtr<TmpFSInode>> TmpFSInode::try_create_root(TmpFS& fs)
+ErrorOr<NonnullLockRefPtr<RAMFSInode>> RAMFSInode::try_create_root(RAMFS& fs)
 {
-    return adopt_nonnull_lock_ref_or_enomem(new (nothrow) TmpFSInode(fs));
+    return adopt_nonnull_lock_ref_or_enomem(new (nothrow) RAMFSInode(fs));
 }
 
-InodeMetadata TmpFSInode::metadata() const
+InodeMetadata RAMFSInode::metadata() const
 {
     MutexLocker locker(m_inode_lock, Mutex::Mode::Shared);
 
     return m_metadata;
 }
 
-ErrorOr<void> TmpFSInode::traverse_as_directory(Function<ErrorOr<void>(FileSystem::DirectoryEntryView const&)> callback) const
+ErrorOr<void> RAMFSInode::traverse_as_directory(Function<ErrorOr<void>(FileSystem::DirectoryEntryView const&)> callback) const
 {
     MutexLocker locker(m_inode_lock, Mutex::Mode::Shared);
 
@@ -69,7 +69,7 @@ ErrorOr<void> TmpFSInode::traverse_as_directory(Function<ErrorOr<void>(FileSyste
     return {};
 }
 
-ErrorOr<void> TmpFSInode::replace_child(StringView name, Inode& new_child)
+ErrorOr<void> RAMFSInode::replace_child(StringView name, Inode& new_child)
 {
     MutexLocker locker(m_inode_lock);
     VERIFY(is_directory());
@@ -80,7 +80,7 @@ ErrorOr<void> TmpFSInode::replace_child(StringView name, Inode& new_child)
         return ENOENT;
 
     auto old_child = child->inode;
-    child->inode = static_cast<TmpFSInode&>(new_child);
+    child->inode = static_cast<RAMFSInode&>(new_child);
 
     old_child->did_delete_self();
 
@@ -89,13 +89,13 @@ ErrorOr<void> TmpFSInode::replace_child(StringView name, Inode& new_child)
     return {};
 }
 
-ErrorOr<NonnullOwnPtr<TmpFSInode::DataBlock>> TmpFSInode::DataBlock::create()
+ErrorOr<NonnullOwnPtr<RAMFSInode::DataBlock>> RAMFSInode::DataBlock::create()
 {
     auto data_block_buffer_vmobject = TRY(Memory::AnonymousVMObject::try_create_with_size(DataBlock::block_size, AllocationStrategy::AllocateNow));
     return TRY(adopt_nonnull_own_or_enomem(new (nothrow) DataBlock(move(data_block_buffer_vmobject))));
 }
 
-ErrorOr<void> TmpFSInode::ensure_allocated_blocks(size_t offset, size_t io_size)
+ErrorOr<void> RAMFSInode::ensure_allocated_blocks(size_t offset, size_t io_size)
 {
     VERIFY(m_inode_lock.is_locked());
     size_t block_start_index = offset / DataBlock::block_size;
@@ -123,31 +123,31 @@ ErrorOr<void> TmpFSInode::ensure_allocated_blocks(size_t offset, size_t io_size)
     return {};
 }
 
-ErrorOr<size_t> TmpFSInode::read_bytes_from_content_space(size_t offset, size_t io_size, UserOrKernelBuffer& buffer) const
+ErrorOr<size_t> RAMFSInode::read_bytes_from_content_space(size_t offset, size_t io_size, UserOrKernelBuffer& buffer) const
 {
     VERIFY(m_inode_lock.is_locked());
     VERIFY(m_metadata.size >= 0);
     if (static_cast<size_t>(m_metadata.size) < offset)
         return 0;
-    auto mapping_region = TRY(MM.allocate_kernel_region(DataBlock::block_size, "TmpFSInode Mapping Region"sv, Memory::Region::Access::Read, AllocationStrategy::Reserve));
+    auto mapping_region = TRY(MM.allocate_kernel_region(DataBlock::block_size, "RAMFSInode Mapping Region"sv, Memory::Region::Access::Read, AllocationStrategy::Reserve));
-    return const_cast<TmpFSInode&>(*this).do_io_on_content_space(*mapping_region, offset, io_size, buffer, false);
+    return const_cast<RAMFSInode&>(*this).do_io_on_content_space(*mapping_region, offset, io_size, buffer, false);
 }
 
-ErrorOr<size_t> TmpFSInode::read_bytes_locked(off_t offset, size_t size, UserOrKernelBuffer& buffer, OpenFileDescription*) const
+ErrorOr<size_t> RAMFSInode::read_bytes_locked(off_t offset, size_t size, UserOrKernelBuffer& buffer, OpenFileDescription*) const
 {
     VERIFY(m_inode_lock.is_locked());
     VERIFY(!is_directory());
     return read_bytes_from_content_space(offset, size, buffer);
 }
 
-ErrorOr<size_t> TmpFSInode::write_bytes_to_content_space(size_t offset, size_t io_size, UserOrKernelBuffer const& buffer)
+ErrorOr<size_t> RAMFSInode::write_bytes_to_content_space(size_t offset, size_t io_size, UserOrKernelBuffer const& buffer)
 {
     VERIFY(m_inode_lock.is_locked());
-    auto mapping_region = TRY(MM.allocate_kernel_region(DataBlock::block_size, "TmpFSInode Mapping Region"sv, Memory::Region::Access::Write, AllocationStrategy::Reserve));
+    auto mapping_region = TRY(MM.allocate_kernel_region(DataBlock::block_size, "RAMFSInode Mapping Region"sv, Memory::Region::Access::Write, AllocationStrategy::Reserve));
     return do_io_on_content_space(*mapping_region, offset, io_size, const_cast<UserOrKernelBuffer&>(buffer), true);
 }
 
-ErrorOr<size_t> TmpFSInode::write_bytes_locked(off_t offset, size_t size, UserOrKernelBuffer const& buffer, OpenFileDescription*)
+ErrorOr<size_t> RAMFSInode::write_bytes_locked(off_t offset, size_t size, UserOrKernelBuffer const& buffer, OpenFileDescription*)
 {
     VERIFY(m_inode_lock.is_locked());
     VERIFY(!is_directory());
@@ -169,7 +169,7 @@ ErrorOr<size_t> TmpFSInode::write_bytes_locked(off_t offset, size_t size, UserOr
     return nwritten;
 }
 
-ErrorOr<size_t> TmpFSInode::do_io_on_content_space(Memory::Region& mapping_region, size_t offset, size_t io_size, UserOrKernelBuffer& buffer, bool write)
+ErrorOr<size_t> RAMFSInode::do_io_on_content_space(Memory::Region& mapping_region, size_t offset, size_t io_size, UserOrKernelBuffer& buffer, bool write)
 {
     VERIFY(m_inode_lock.is_locked());
     size_t remaining_bytes = 0;
@@ -227,14 +227,14 @@ ErrorOr<size_t> TmpFSInode::do_io_on_content_space(Memory::Region& mapping_regio
     return nio;
 }
 
-ErrorOr<void> TmpFSInode::truncate_to_block_index(size_t block_index)
+ErrorOr<void> RAMFSInode::truncate_to_block_index(size_t block_index)
 {
     VERIFY(m_inode_lock.is_locked());
     TRY(m_blocks.try_resize(block_index));
     return {};
 }
 
-ErrorOr<NonnullLockRefPtr<Inode>> TmpFSInode::lookup(StringView name)
+ErrorOr<NonnullLockRefPtr<Inode>> RAMFSInode::lookup(StringView name)
 {
     MutexLocker locker(m_inode_lock, Mutex::Mode::Shared);
     VERIFY(is_directory());
@@ -253,7 +253,7 @@ ErrorOr<NonnullLockRefPtr<Inode>> TmpFSInode::lookup(StringView name)
     return child->inode;
 }
 
-TmpFSInode::Child* TmpFSInode::find_child_by_name(StringView name)
+RAMFSInode::Child* RAMFSInode::find_child_by_name(StringView name)
 {
     for (auto& child : m_children) {
         if (child.name->view() == name)
@@ -262,7 +262,7 @@ TmpFSInode::Child* TmpFSInode::find_child_by_name(StringView name)
     return nullptr;
 }
 
-ErrorOr<void> TmpFSInode::flush_metadata()
+ErrorOr<void> RAMFSInode::flush_metadata()
 {
     // We don't really have any metadata that could become dirty.
     // The only reason we even call set_metadata_dirty() is
@@ -273,7 +273,7 @@ ErrorOr<void> TmpFSInode::flush_metadata()
     return {};
 }
 
-ErrorOr<void> TmpFSInode::chmod(mode_t mode)
+ErrorOr<void> RAMFSInode::chmod(mode_t mode)
 {
     MutexLocker locker(m_inode_lock);
 
@@ -282,7 +282,7 @@ ErrorOr<void> TmpFSInode::chmod(mode_t mode)
     return {};
 }
 
-ErrorOr<void> TmpFSInode::chown(UserID uid, GroupID gid)
+ErrorOr<void> RAMFSInode::chown(UserID uid, GroupID gid)
 {
     MutexLocker locker(m_inode_lock);
 
@@ -292,7 +292,7 @@ ErrorOr<void> TmpFSInode::chown(UserID uid, GroupID gid)
     return {};
 }
 
-ErrorOr<NonnullLockRefPtr<Inode>> TmpFSInode::create_child(StringView name, mode_t mode, dev_t dev, UserID uid, GroupID gid)
+ErrorOr<NonnullLockRefPtr<Inode>> RAMFSInode::create_child(StringView name, mode_t mode, dev_t dev, UserID uid, GroupID gid)
 {
     MutexLocker locker(m_inode_lock);
     auto now = kgettimeofday();
@@ -307,12 +307,12 @@ ErrorOr<NonnullLockRefPtr<Inode>> TmpFSInode::create_child(StringView name, mode
     metadata.major_device = major_from_encoded_device(dev);
     metadata.minor_device = minor_from_encoded_device(dev);
 
-    auto child = TRY(TmpFSInode::try_create(fs(), metadata, *this));
+    auto child = TRY(RAMFSInode::try_create(fs(), metadata, *this));
     TRY(add_child(*child, name, mode));
     return child;
 }
 
-ErrorOr<void> TmpFSInode::add_child(Inode& child, StringView name, mode_t)
+ErrorOr<void> RAMFSInode::add_child(Inode& child, StringView name, mode_t)
 {
     VERIFY(is_directory());
     VERIFY(child.fsid() == fsid());
@@ -329,7 +329,7 @@ ErrorOr<void> TmpFSInode::add_child(Inode& child, StringView name, mode_t)
     auto name_kstring = TRY(KString::try_create(name));
     // Balanced by `delete` in remove_child()
 
-    auto* child_entry = new (nothrow) Child { move(name_kstring), static_cast<TmpFSInode&>(child) };
+    auto* child_entry = new (nothrow) Child { move(name_kstring), static_cast<RAMFSInode&>(child) };
     if (!child_entry)
         return ENOMEM;
 
@@ -338,7 +338,7 @@ ErrorOr<void> TmpFSInode::add_child(Inode& child, StringView name, mode_t)
     return {};
 }
 
-ErrorOr<void> TmpFSInode::remove_child(StringView name)
+ErrorOr<void> RAMFSInode::remove_child(StringView name)
 {
     MutexLocker locker(m_inode_lock);
     VERIFY(is_directory());
@@ -359,7 +359,7 @@ ErrorOr<void> TmpFSInode::remove_child(StringView name)
     return {};
 }
 
-ErrorOr<void> TmpFSInode::truncate(u64 size)
+ErrorOr<void> RAMFSInode::truncate(u64 size)
 {
     MutexLocker locker(m_inode_lock);
     VERIFY(!is_directory());
@@ -369,7 +369,7 @@ ErrorOr<void> TmpFSInode::truncate(u64 size)
 
     u64 last_possible_block_index = size / DataBlock::block_size;
     if ((size % DataBlock::block_size != 0) && m_blocks[last_possible_block_index]) {
-        auto mapping_region = TRY(MM.allocate_kernel_region(DataBlock::block_size, "TmpFSInode Mapping Region"sv, Memory::Region::Access::Write, AllocationStrategy::Reserve));
+        auto mapping_region = TRY(MM.allocate_kernel_region(DataBlock::block_size, "RAMFSInode Mapping Region"sv, Memory::Region::Access::Write, AllocationStrategy::Reserve));
         VERIFY(m_blocks[last_possible_block_index]);
         NonnullLockRefPtr<Memory::AnonymousVMObject> block_vmobject = m_blocks[last_possible_block_index]->vmobject();
         mapping_region->set_vmobject(block_vmobject);
@@ -381,7 +381,7 @@ ErrorOr<void> TmpFSInode::truncate(u64 size)
     return {};
 }
 
-ErrorOr<void> TmpFSInode::update_timestamps(Optional<Time> atime, Optional<Time> ctime, Optional<Time> mtime)
+ErrorOr<void> RAMFSInode::update_timestamps(Optional<Time> atime, Optional<Time> ctime, Optional<Time> mtime)
 {
     MutexLocker locker(m_inode_lock);
 

Kernel/FileSystem/RAMFS/Inode.h

@@ -1,6 +1,6 @@
 /*
  * Copyright (c) 2019-2020, Sergey Bugaev <bugaevc@serenityos.org>
- * Copyright (c) 2022, Liav A. <liavalb@hotmail.co.il>
+ * Copyright (c) 2022-2023, Liav A. <liavalb@hotmail.co.il>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -8,19 +8,20 @@
 #pragma once
 
 #include <Kernel/FileSystem/Inode.h>
-#include <Kernel/FileSystem/TmpFS/FileSystem.h>
+#include <Kernel/FileSystem/RAMFS/FileSystem.h>
+#include <Kernel/Forward.h>
 #include <Kernel/Memory/AnonymousVMObject.h>
 
 namespace Kernel {
 
-class TmpFSInode final : public Inode {
+class RAMFSInode final : public Inode {
-    friend class TmpFS;
+    friend class RAMFS;
 
 public:
-    virtual ~TmpFSInode() override;
+    virtual ~RAMFSInode() override;
 
-    TmpFS& fs() { return static_cast<TmpFS&>(Inode::fs()); }
+    RAMFS& fs() { return static_cast<RAMFS&>(Inode::fs()); }
-    TmpFS const& fs() const { return static_cast<TmpFS const&>(Inode::fs()); }
+    RAMFS const& fs() const { return static_cast<RAMFS const&>(Inode::fs()); }
 
     // ^Inode
     virtual InodeMetadata metadata() const override;
@@ -37,10 +38,10 @@ public:
     virtual ErrorOr<void> update_timestamps(Optional<Time> atime, Optional<Time> ctime, Optional<Time> mtime) override;
 
 private:
-    TmpFSInode(TmpFS& fs, InodeMetadata const& metadata, LockWeakPtr<TmpFSInode> parent);
+    RAMFSInode(RAMFS& fs, InodeMetadata const& metadata, LockWeakPtr<RAMFSInode> parent);
-    explicit TmpFSInode(TmpFS& fs);
+    explicit RAMFSInode(RAMFS& fs);
-    static ErrorOr<NonnullLockRefPtr<TmpFSInode>> try_create(TmpFS&, InodeMetadata const& metadata, LockWeakPtr<TmpFSInode> parent);
+    static ErrorOr<NonnullLockRefPtr<RAMFSInode>> try_create(RAMFS&, InodeMetadata const& metadata, LockWeakPtr<RAMFSInode> parent);
-    static ErrorOr<NonnullLockRefPtr<TmpFSInode>> try_create_root(TmpFS&);
+    static ErrorOr<NonnullLockRefPtr<RAMFSInode>> try_create_root(RAMFS&);
 
     // ^Inode
     virtual ErrorOr<size_t> read_bytes_locked(off_t, size_t, UserOrKernelBuffer& buffer, OpenFileDescription*) const override;
@@ -50,7 +51,7 @@ private:
 
     struct Child {
         NonnullOwnPtr<KString> name;
-        NonnullLockRefPtr<TmpFSInode> inode;
+        NonnullLockRefPtr<RAMFSInode> inode;
         IntrusiveListNode<Child> list_node {};
         using List = IntrusiveList<&Child::list_node>;
     };
@@ -58,7 +59,7 @@ private:
     Child* find_child_by_name(StringView);
 
     InodeMetadata m_metadata;
-    LockWeakPtr<TmpFSInode> m_parent;
+    LockWeakPtr<RAMFSInode> m_parent;
 
     ErrorOr<void> ensure_allocated_blocks(size_t offset, size_t io_size);
     ErrorOr<void> truncate_to_block_index(size_t block_index);

Kernel/FileSystem/TmpFS/FileSystem.cpp

@@ -1,40 +0,0 @@
-/*
- * Copyright (c) 2019-2020, Sergey Bugaev <bugaevc@serenityos.org>
- * Copyright (c) 2022, Liav A. <liavalb@hotmail.co.il>
- *
- * SPDX-License-Identifier: BSD-2-Clause
- */
-
-#include <Kernel/FileSystem/TmpFS/FileSystem.h>
-#include <Kernel/FileSystem/TmpFS/Inode.h>
-
-namespace Kernel {
-
-ErrorOr<NonnullLockRefPtr<FileSystem>> TmpFS::try_create()
-{
-    return TRY(adopt_nonnull_lock_ref_or_enomem(new (nothrow) TmpFS));
-}
-
-TmpFS::TmpFS() = default;
-TmpFS::~TmpFS() = default;
-
-ErrorOr<void> TmpFS::initialize()
-{
-    m_root_inode = TRY(TmpFSInode::try_create_root(*this));
-    return {};
-}
-
-Inode& TmpFS::root_inode()
-{
-    VERIFY(!m_root_inode.is_null());
-    return *m_root_inode;
-}
-
-unsigned TmpFS::next_inode_index()
-{
-    MutexLocker locker(m_lock);
-
-    return m_next_inode_index++;
-}
-
-}

Kernel/Forward.h

@@ -49,6 +49,7 @@ class ProcFSSystemBoolean;
 class ProcFSSystemDirectory;
 class Process;
 class ProcessGroup;
+class RAMFS;
 template<LockRank Rank>
 class RecursiveSpinlock;
 class Scheduler;
@@ -64,7 +65,7 @@ class TCPSocket;
 class TTY;
 class Thread;
 class ThreadTracer;
-class TmpFSInode;
+class RAMFSInode;
 class UDPSocket;
 class UserOrKernelBuffer;
 class VirtualFileSystem;

Kernel/Syscalls/mount.cpp

@@ -11,8 +11,8 @@
 #include <Kernel/FileSystem/ISO9660FS/FileSystem.h>
 #include <Kernel/FileSystem/Plan9FS/FileSystem.h>
 #include <Kernel/FileSystem/ProcFS/FileSystem.h>
+#include <Kernel/FileSystem/RAMFS/FileSystem.h>
 #include <Kernel/FileSystem/SysFS/FileSystem.h>
-#include <Kernel/FileSystem/TmpFS/FileSystem.h>
 #include <Kernel/FileSystem/VirtualFileSystem.h>
 #include <Kernel/Process.h>
 
@@ -32,7 +32,7 @@ static constexpr FileSystemInitializer s_initializers[] = {
     { "proc"sv, "ProcFS"sv, false, false, false, {}, ProcFS::try_create },
     { "devpts"sv, "DevPtsFS"sv, false, false, false, {}, DevPtsFS::try_create },
     { "sys"sv, "SysFS"sv, false, false, false, {}, SysFS::try_create },
-    { "tmp"sv, "TmpFS"sv, false, false, false, {}, TmpFS::try_create },
+    { "ram"sv, "RAMFS"sv, false, false, false, {}, RAMFS::try_create },
     { "ext2"sv, "Ext2FS"sv, true, true, true, Ext2FS::try_create, {} },
     { "9p"sv, "Plan9FS"sv, true, true, true, Plan9FS::try_create, {} },
     { "iso9660"sv, "ISO9660FS"sv, true, true, true, ISO9660FS::try_create, {} },

Userland/Services/SystemServer/main.cpp

@@ -389,7 +389,11 @@ static ErrorOr<void> prepare_synthetic_filesystems()
     // FIXME: Find a better way to all of this stuff, without hardcoding all of this!
     TRY(Core::System::mount(-1, "/proc"sv, "proc"sv, MS_NOSUID));
     TRY(Core::System::mount(-1, "/sys"sv, "sys"sv, 0));
-    TRY(Core::System::mount(-1, "/dev"sv, "tmp"sv, MS_NOSUID | MS_NOEXEC | MS_NOREGULAR));
+    TRY(Core::System::mount(-1, "/dev"sv, "ram"sv, MS_NOSUID | MS_NOEXEC | MS_NOREGULAR));
+
+    TRY(Core::System::mount(-1, "/tmp"sv, "ram"sv, MS_NOSUID | MS_NODEV));
+    // NOTE: Set /tmp to have a sticky bit with 0777 permissions.
+    TRY(Core::System::chmod("/tmp"sv, 01777));
 
     TRY(Core::System::mkdir("/dev/audio"sv, 0755));
     TRY(Core::System::mkdir("/dev/input"sv, 0755));