From ac4583660b2c7da33ac13b4733f993767bb08644 Mon Sep 17 00:00:00 2001
From: Idan Horowitz <idan.horowitz@gmail.com>
Date: Wed, 26 Jan 2022 22:03:48 +0200
Subject: [PATCH] Kernel: Make VirtIO::ConsolePort construction OOM-fallible

---
 Kernel/Bus/VirtIO/ConsolePort.cpp | 13 ++++++++++---
 Kernel/Bus/VirtIO/ConsolePort.h   |  9 ++++++---
 2 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/Kernel/Bus/VirtIO/ConsolePort.cpp b/Kernel/Bus/VirtIO/ConsolePort.cpp
index c484879da9..b13729d8ec 100644
--- a/Kernel/Bus/VirtIO/ConsolePort.cpp
+++ b/Kernel/Bus/VirtIO/ConsolePort.cpp
@@ -12,13 +12,20 @@ namespace Kernel::VirtIO {
 
 unsigned ConsolePort::next_device_id = 0;
 
-ConsolePort::ConsolePort(unsigned port, VirtIO::Console& console)
+ErrorOr<NonnullRefPtr<ConsolePort>> ConsolePort::try_create(unsigned port, Console& console)
+{
+    auto receive_buffer = TRY(Memory::RingBuffer::try_create("VirtIO::ConsolePort Receive"sv, RINGBUFFER_SIZE));
+    auto transmit_buffer = TRY(Memory::RingBuffer::try_create("VirtIO::ConsolePort Transmit"sv, RINGBUFFER_SIZE));
+    return adopt_nonnull_ref_or_enomem(new (nothrow) ConsolePort(port, console, move(receive_buffer), move(transmit_buffer)));
+}
+
+ConsolePort::ConsolePort(unsigned port, VirtIO::Console& console, NonnullOwnPtr<Memory::RingBuffer> receive_buffer, NonnullOwnPtr<Memory::RingBuffer> transmit_buffer)
     : CharacterDevice(229, next_device_id++)
+    , m_receive_buffer(move(receive_buffer))
+    , m_transmit_buffer(move(transmit_buffer))
     , m_console(console)
     , m_port(port)
 {
-    m_receive_buffer = Memory::RingBuffer::try_create("VirtIO::ConsolePort Receive"sv, RINGBUFFER_SIZE).release_value_but_fixme_should_propagate_errors();
-    m_transmit_buffer = Memory::RingBuffer::try_create("VirtIO::ConsolePort Transmit"sv, RINGBUFFER_SIZE).release_value_but_fixme_should_propagate_errors();
     m_receive_queue = m_port == 0 ? 0 : m_port * 2 + 2;
     m_transmit_queue = m_port == 0 ? 1 : m_port * 2 + 3;
 }
diff --git a/Kernel/Bus/VirtIO/ConsolePort.h b/Kernel/Bus/VirtIO/ConsolePort.h
index 40797ab397..beed06e1a2 100644
--- a/Kernel/Bus/VirtIO/ConsolePort.h
+++ b/Kernel/Bus/VirtIO/ConsolePort.h
@@ -24,7 +24,8 @@ class Console;
 class ConsolePort
     : public CharacterDevice {
 public:
-    explicit ConsolePort(unsigned port, VirtIO::Console&);
+    static ErrorOr<NonnullRefPtr<ConsolePort>> try_create(unsigned port, VirtIO::Console&);
+
     void handle_queue_update(Badge<VirtIO::Console>, u16 queue_index);
 
     void set_open(Badge<VirtIO::Console>, bool state) { m_open = state; }
@@ -35,6 +36,8 @@ public:
 private:
     constexpr static size_t RINGBUFFER_SIZE = 2 * PAGE_SIZE;
 
+    ConsolePort(unsigned port, VirtIO::Console& console, NonnullOwnPtr<Memory::RingBuffer> receive_buffer, NonnullOwnPtr<Memory::RingBuffer> transmit_buffer);
+
     virtual StringView class_name() const override { return "VirtIOConsolePort"sv; }
 
     virtual bool can_read(const OpenFileDescription&, u64) const override;
@@ -47,8 +50,8 @@ private:
     u16 m_receive_queue {};
     u16 m_transmit_queue {};
 
-    OwnPtr<Memory::RingBuffer> m_receive_buffer;
-    OwnPtr<Memory::RingBuffer> m_transmit_buffer;
+    NonnullOwnPtr<Memory::RingBuffer> m_receive_buffer;
+    NonnullOwnPtr<Memory::RingBuffer> m_transmit_buffer;
 
     VirtIO::Console& m_console;
     unsigned m_port;