From 8e90a4fd1c4162f26d7e276db6d83005d165abde Mon Sep 17 00:00:00 2001
From: Liav A <liavalb@gmail.com>
Date: Fri, 27 Aug 2021 12:32:05 +0300
Subject: [PATCH] Kernel/VirtIO: Don't expose constructors as public method

This leads to a bad pattern where anyone could create an RNG or a
Console object. Instead, let's just use the common pattern of a static
method to instantiate a new object and return it wrapped by a
NonnullRefPtr.
---
 Kernel/Bus/VirtIO/Console.cpp | 5 +++++
 Kernel/Bus/VirtIO/Console.h   | 3 ++-
 Kernel/Bus/VirtIO/Device.cpp  | 4 ++--
 Kernel/Bus/VirtIO/RNG.cpp     | 5 +++++
 Kernel/Bus/VirtIO/RNG.h       | 4 ++--
 5 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/Kernel/Bus/VirtIO/Console.cpp b/Kernel/Bus/VirtIO/Console.cpp
index ab6d3b02ef..6902214ca9 100644
--- a/Kernel/Bus/VirtIO/Console.cpp
+++ b/Kernel/Bus/VirtIO/Console.cpp
@@ -12,6 +12,11 @@ namespace Kernel::VirtIO {
 
 unsigned Console::next_device_id = 0;
 
+UNMAP_AFTER_INIT NonnullRefPtr<Console> Console::must_create(PCI::Address address)
+{
+    return adopt_ref_if_nonnull(new Console(address)).release_nonnull();
+}
+
 UNMAP_AFTER_INIT Console::Console(PCI::Address address)
     : VirtIO::Device(address)
     , m_device_id(next_device_id++)
diff --git a/Kernel/Bus/VirtIO/Console.h b/Kernel/Bus/VirtIO/Console.h
index a9bb01cb50..3a303166ff 100644
--- a/Kernel/Bus/VirtIO/Console.h
+++ b/Kernel/Bus/VirtIO/Console.h
@@ -18,7 +18,7 @@ class Console
     friend VirtIO::ConsolePort;
 
 public:
-    Console(PCI::Address);
+    static NonnullRefPtr<Console> must_create(PCI::Address address);
     virtual ~Console() override = default;
 
     virtual StringView purpose() const override { return class_name(); }
@@ -30,6 +30,7 @@ public:
 
 private:
     virtual StringView class_name() const override { return "VirtIOConsole"; }
+    explicit Console(PCI::Address);
     enum class ControlEvent : u16 {
         DeviceReady = 0,
         DeviceAdd = 1,
diff --git a/Kernel/Bus/VirtIO/Device.cpp b/Kernel/Bus/VirtIO/Device.cpp
index dbf78073bb..320c3e5566 100644
--- a/Kernel/Bus/VirtIO/Device.cpp
+++ b/Kernel/Bus/VirtIO/Device.cpp
@@ -25,11 +25,11 @@ UNMAP_AFTER_INIT void detect()
             return;
         switch (id.device_id) {
         case PCI::DeviceID::VirtIOConsole: {
-            [[maybe_unused]] auto& unused = adopt_ref(*new Console(address)).leak_ref();
+            [[maybe_unused]] auto& unused = Console::must_create(address).leak_ref();
             break;
         }
         case PCI::DeviceID::VirtIOEntropy: {
-            [[maybe_unused]] auto& unused = adopt_ref(*new RNG(address)).leak_ref();
+            [[maybe_unused]] auto& unused = RNG::must_create(address).leak_ref();
             break;
         }
         case PCI::DeviceID::VirtIOGPU: {
diff --git a/Kernel/Bus/VirtIO/RNG.cpp b/Kernel/Bus/VirtIO/RNG.cpp
index b4db822d9b..5bdaedc449 100644
--- a/Kernel/Bus/VirtIO/RNG.cpp
+++ b/Kernel/Bus/VirtIO/RNG.cpp
@@ -9,6 +9,11 @@
 
 namespace Kernel::VirtIO {
 
+UNMAP_AFTER_INIT NonnullRefPtr<RNG> RNG::must_create(PCI::Address address)
+{
+    return adopt_ref_if_nonnull(new RNG(address)).release_nonnull();
+}
+
 UNMAP_AFTER_INIT RNG::RNG(PCI::Address address)
     : VirtIO::Device(address)
 {
diff --git a/Kernel/Bus/VirtIO/RNG.h b/Kernel/Bus/VirtIO/RNG.h
index ea4e8c775d..bc7947b0e0 100644
--- a/Kernel/Bus/VirtIO/RNG.h
+++ b/Kernel/Bus/VirtIO/RNG.h
@@ -19,13 +19,13 @@ class RNG final
     : public RefCounted<RNG>
     , public VirtIO::Device {
 public:
+    static NonnullRefPtr<RNG> must_create(PCI::Address address);
     virtual StringView purpose() const override { return class_name(); }
-
-    RNG(PCI::Address);
     virtual ~RNG() override;
 
 private:
     virtual StringView class_name() const override { return "VirtIOConsole"; }
+    explicit RNG(PCI::Address);
     virtual bool handle_device_config_change() override;
     virtual void handle_queue_update(u16 queue_index) override;
     void request_entropy_from_host();