A bit of a redesign.

Sessions and Ports are now detached from each other.
HLE services are handled by means of a SessionRequestHandler class, Interface now inherits from this class.
The File and Directory classes are no longer kernel objects, but SessionRequestHandlers instead, bound to a ServerSession when requested.
File::OpenLinkFile now creates a new session pair and binds the File instance to it.

src/core/hle/service/service.h

@@ -10,8 +10,163 @@
 #include <boost/container/flat_map.hpp>
 #include "common/common_types.h"
 #include "core/hle/kernel/client_port.h"
-#include "core/hle/kernel/server_session.h"
+#include "core/hle/kernel/thread.h"
 #include "core/hle/result.h"
+#include "core/memory.h"
+
+namespace Kernel {
+class ServerSession;
+
+// TODO(Subv): Move these declarations out of here
+static const int kCommandHeaderOffset = 0x80; ///< Offset into command buffer of header
+
+/**
+ * Returns a pointer to the command buffer in the current thread's TLS
+ * TODO(Subv): This is not entirely correct, the command buffer should be copied from
+ * the thread's TLS to an intermediate buffer in kernel memory, and then copied again to
+ * the service handler process' memory.
+ * @param offset Optional offset into command buffer
+ * @return Pointer to command buffer
+ */
+inline u32* GetCommandBuffer(const int offset = 0) {
+    return (u32*)Memory::GetPointer(GetCurrentThread()->GetTLSAddress() + kCommandHeaderOffset +
+                                    offset);
+}
+}
+
+// TODO(Subv): Move this namespace out of here
+namespace IPC {
+
+enum DescriptorType : u32 {
+    // Buffer related desciptors types (mask : 0x0F)
+    StaticBuffer = 0x02,
+    PXIBuffer = 0x04,
+    MappedBuffer = 0x08,
+    // Handle related descriptors types (mask : 0x30, but need to check for buffer related
+    // descriptors first )
+    CopyHandle = 0x00,
+    MoveHandle = 0x10,
+    CallingPid = 0x20,
+};
+
+/**
+* @brief Creates a command header to be used for IPC
+* @param command_id            ID of the command to create a header for.
+* @param normal_params         Size of the normal parameters in words. Up to 63.
+* @param translate_params_size Size of the translate parameters in words. Up to 63.
+* @return The created IPC header.
+*
+* Normal parameters are sent directly to the process while the translate parameters might go
+* through modifications and checks by the kernel.
+* The translate parameters are described by headers generated with the IPC::*Desc functions.
+*
+* @note While #normal_params is equivalent to the number of normal parameters,
+* #translate_params_size includes the size occupied by the translate parameters headers.
+*/
+constexpr u32 MakeHeader(u16 command_id, unsigned int normal_params,
+                         unsigned int translate_params_size) {
+    return (u32(command_id) << 16) | ((u32(normal_params) & 0x3F) << 6) |
+        (u32(translate_params_size) & 0x3F);
+}
+
+union Header {
+    u32 raw;
+    BitField<0, 6, u32> translate_params_size;
+    BitField<6, 6, u32> normal_params;
+    BitField<16, 16, u32> command_id;
+};
+
+inline Header ParseHeader(u32 header) {
+    return{ header };
+}
+
+constexpr u32 MoveHandleDesc(u32 num_handles = 1) {
+    return MoveHandle | ((num_handles - 1) << 26);
+}
+
+constexpr u32 CopyHandleDesc(u32 num_handles = 1) {
+    return CopyHandle | ((num_handles - 1) << 26);
+}
+
+constexpr u32 CallingPidDesc() {
+    return CallingPid;
+}
+
+constexpr bool isHandleDescriptor(u32 descriptor) {
+    return (descriptor & 0xF) == 0x0;
+}
+
+constexpr u32 HandleNumberFromDesc(u32 handle_descriptor) {
+    return (handle_descriptor >> 26) + 1;
+}
+
+constexpr u32 StaticBufferDesc(u32 size, u8 buffer_id) {
+    return StaticBuffer | (size << 14) | ((buffer_id & 0xF) << 10);
+}
+
+union StaticBufferDescInfo {
+    u32 raw;
+    BitField<10, 4, u32> buffer_id;
+    BitField<14, 18, u32> size;
+};
+
+inline StaticBufferDescInfo ParseStaticBufferDesc(const u32 desc) {
+    return{ desc };
+}
+
+/**
+* @brief Creates a header describing a buffer to be sent over PXI.
+* @param size         Size of the buffer. Max 0x00FFFFFF.
+* @param buffer_id    The Id of the buffer. Max 0xF.
+* @param is_read_only true if the buffer is read-only. If false, the buffer is considered to have
+* read-write access.
+* @return The created PXI buffer header.
+*
+* The next value is a phys-address of a table located in the BASE memregion.
+*/
+inline u32 PXIBufferDesc(u32 size, unsigned buffer_id, bool is_read_only) {
+    u32 type = PXIBuffer;
+    if (is_read_only)
+        type |= 0x2;
+    return type | (size << 8) | ((buffer_id & 0xF) << 4);
+}
+
+enum MappedBufferPermissions {
+    R = 1,
+    W = 2,
+    RW = R | W,
+};
+
+constexpr u32 MappedBufferDesc(u32 size, MappedBufferPermissions perms) {
+    return MappedBuffer | (size << 4) | (u32(perms) << 1);
+}
+
+union MappedBufferDescInfo {
+    u32 raw;
+    BitField<4, 28, u32> size;
+    BitField<1, 2, MappedBufferPermissions> perms;
+};
+
+inline MappedBufferDescInfo ParseMappedBufferDesc(const u32 desc) {
+    return{ desc };
+}
+
+inline DescriptorType GetDescriptorType(u32 descriptor) {
+    // Note: Those checks must be done in this order
+    if (isHandleDescriptor(descriptor))
+        return (DescriptorType)(descriptor & 0x30);
+
+    // handle the fact that the following descriptors can have rights
+    if (descriptor & MappedBuffer)
+        return MappedBuffer;
+
+    if (descriptor & PXIBuffer)
+        return PXIBuffer;
+
+    return StaticBuffer;
+}
+
+} // namespace IPC
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 // Namespace Service
@@ -21,8 +176,22 @@ namespace Service {
 static const int kMaxPortSize = 8; ///< Maximum size of a port name (8 characters)
 static const u32 DefaultMaxSessions = 10; ///< Arbitrary default number of maximum connections to an HLE port
 
+/// TODO(Subv): Write documentation for this class
+class SessionRequestHandler {
+public:
+    /**
+     * Dispatches and handles a sync request from the emulated application.
+     * @param server_session The ServerSession that was triggered for this sync request,
+     * it should be used to differentiate which client (As in ClientSession) we're answering to.
+     * TODO(Subv): Make a HandleSyncRequestParent function that is called from the outside and does { ReturnIfError(Translate()); HandleSyncRequest(); }
+     * The Translate() function would copy the command buffer from the ServerSession thread's TLS into a temporary buffer, and pass it to HandleSyncRequest.
+     * TODO(Subv): HandleSyncRequest's return type should be void.
+     */
+    virtual ResultCode HandleSyncRequest(Kernel::SharedPtr<Kernel::ServerSession> server_session) = 0;
+};
+
 /// Interface to a CTROS service
-class Interface {
+class Interface : public SessionRequestHandler {
 public:
     std::string GetName() const {
         return GetPortName();
@@ -56,7 +225,7 @@ public:
         return "[UNKNOWN SERVICE PORT]";
     }
 
-    ResultCode HandleSyncRequest(Kernel::SharedPtr<Kernel::ServerSession> server_session);
+    ResultCode HandleSyncRequest(Kernel::SharedPtr<Kernel::ServerSession> server_session) override;
 
 protected:
     /**
@@ -88,9 +257,9 @@ void Init();
 void Shutdown();
 
 /// Map of named ports managed by the kernel, which can be retrieved using the ConnectToPort SVC.
-extern std::unordered_map<std::string, Kernel::SharedPtr<Kernel::ClientPort>> g_kernel_named_ports;
+extern std::unordered_map<std::string, std::tuple<Kernel::SharedPtr<Kernel::ClientPort>, std::shared_ptr<Interface>>> g_kernel_named_ports;
 /// Map of services registered with the "srv:" service, retrieved using GetServiceHandle.
-extern std::unordered_map<std::string, Kernel::SharedPtr<Kernel::ClientPort>> g_srv_services;
+extern std::unordered_map<std::string, std::tuple<Kernel::SharedPtr<Kernel::ClientPort>, std::shared_ptr<Interface>>> g_srv_services;
 
 /// Adds a service to the services table
 void AddService(Interface* interface_);