1 files changed, 58 insertions, 0 deletions

diff --git a/src/core/hle/kernel/session.h b/src/core/hle/kernel/session.h
new file mode 100644
index 000000000..06ae4bc39
--- /dev/null
+++ b/src/core/hle/kernel/session.h
@@ -0,0 +1,58 @@
+// Copyright 2014 Citra Emulator Project
+// Licensed under GPLv2+
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include "core/hle/kernel/kernel.h"
+
+namespace Kernel {
+
+static const int kCommandHeaderOffset = 0x80; ///< Offset into command buffer of header
+
+/**
+ * Returns a pointer to the command buffer in kernel memory
+ * @param offset Optional offset into command buffer
+ * @return Pointer to command buffer
+ */
+inline static u32* GetCommandBuffer(const int offset=0) {
+    return (u32*)Memory::GetPointer(Memory::KERNEL_MEMORY_VADDR + kCommandHeaderOffset + offset);
+}
+
+/**
+ * Kernel object representing the client endpoint of an IPC session. Sessions are the basic CTR-OS
+ * primitive for communication between different processes, and are used to implement service calls
+ * to the various system services.
+ *
+ * To make a service call, the client must write the command header and parameters to the buffer
+ * located at offset 0x80 of the TLS (Thread-Local Storage) area, then execute a SendSyncRequest
+ * SVC call with its Session handle. The kernel will read the command header, using it to marshall
+ * the parameters to the process at the server endpoint of the session. After the server replies to
+ * the request, the response is marshalled back to the caller's TLS buffer and control is
+ * transferred back to it.
+ *
+ * In Citra, only the client endpoint is currently implemented and only HLE calls, where the IPC
+ * request is answered by C++ code in the emulator, are supported. When SendSyncRequest is called
+ * with the session handle, this class's SyncRequest method is called, which should read the TLS
+ * buffer and emulate the call accordingly. Since the code can directly read the emulated memory,
+ * no parameter marshalling is done.
+ *
+ * In the long term, this should be turned into the full-fledged IPC mechanism implemented by
+ * CTR-OS so that IPC calls can be optionally handled by the real implementations of processes, as
+ * opposed to HLE simulations.
+ */
+class Session : public Object {
+public:
+    std::string GetTypeName() const override { return "Session"; }
+
+    static Kernel::HandleType GetStaticHandleType() { return Kernel::HandleType::Session; }
+    Kernel::HandleType GetHandleType() const override { return Kernel::HandleType::Session; }
+
+    /**
+     * Handles a synchronous call to this session using HLE emulation. Emulated <-> emulated calls
+     * aren't supported yet.
+     */
+    virtual ResultVal<bool> SyncRequest() = 0;
+};
+
+}