Merge pull request #2249 from Subv/sessions_v3

Kernel/IPC: Use Ports and Sessions as the fundamental building block of Inter Process Communication.

src/citra_qt/debugger/wait_tree.cpp

@@ -8,7 +8,6 @@
 #include "core/hle/kernel/event.h"
 #include "core/hle/kernel/mutex.h"
 #include "core/hle/kernel/semaphore.h"
-#include "core/hle/kernel/session.h"
 #include "core/hle/kernel/thread.h"
 #include "core/hle/kernel/timer.h"
 

src/core/CMakeLists.txt

@@ -38,6 +38,7 @@ set(SRCS
             hle/applets/swkbd.cpp
             hle/kernel/address_arbiter.cpp
             hle/kernel/client_port.cpp
+            hle/kernel/client_session.cpp
             hle/kernel/event.cpp
             hle/kernel/kernel.cpp
             hle/kernel/memory.cpp
@@ -46,7 +47,7 @@ set(SRCS
             hle/kernel/resource_limit.cpp
             hle/kernel/semaphore.cpp
             hle/kernel/server_port.cpp
-            hle/kernel/session.cpp
+            hle/kernel/server_session.cpp
             hle/kernel/shared_memory.cpp
             hle/kernel/thread.cpp
             hle/kernel/timer.cpp
@@ -194,12 +195,14 @@ set(HEADERS
             hle/config_mem.h
             hle/function_wrappers.h
             hle/hle.h
+            hle/ipc.h
             hle/applets/applet.h
             hle/applets/erreula.h
             hle/applets/mii_selector.h
             hle/applets/swkbd.h
             hle/kernel/address_arbiter.h
             hle/kernel/client_port.h
+            hle/kernel/client_session.h
             hle/kernel/event.h
             hle/kernel/kernel.h
             hle/kernel/memory.h
@@ -208,7 +211,7 @@ set(HEADERS
             hle/kernel/resource_limit.h
             hle/kernel/semaphore.h
             hle/kernel/server_port.h
-            hle/kernel/session.h
+            hle/kernel/server_session.h
             hle/kernel/shared_memory.h
             hle/kernel/thread.h
             hle/kernel/timer.h

src/core/hle/kernel/session.h → src/core/hle/ipc.h

@@ -1,17 +1,31 @@
-// Copyright 2014 Citra Emulator Project
+// Copyright 2016 Citra Emulator Project
 // Licensed under GPLv2 or any later version
 // Refer to the license.txt file included.
 
 #pragma once
 
-#include <string>
-#include "common/assert.h"
 #include "common/common_types.h"
-#include "core/hle/kernel/kernel.h"
 #include "core/hle/kernel/thread.h"
-#include "core/hle/result.h"
 #include "core/memory.h"
 
+namespace Kernel {
+
+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);
+}
+}
+
 namespace IPC {
 
 enum DescriptorType : u32 {
@@ -144,75 +158,3 @@ inline DescriptorType GetDescriptorType(u32 descriptor) {
 }
 
 } // namespace IPC
-
-namespace Kernel {
-
-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);
-}
-
-/**
- * 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 WaitObject {
-public:
-    Session();
-    ~Session() override;
-
-    std::string GetTypeName() const override {
-        return "Session";
-    }
-
-    static const HandleType HANDLE_TYPE = HandleType::Session;
-    HandleType GetHandleType() const override {
-        return HANDLE_TYPE;
-    }
-
-    /**
-     * Handles a synchronous call to this session using HLE emulation. Emulated <-> emulated calls
-     * aren't supported yet.
-     */
-    virtual ResultVal<bool> SyncRequest() = 0;
-
-    // TODO(bunnei): These functions exist to satisfy a hardware test with a Session object
-    // passed into WaitSynchronization. Figure out the meaning of them.
-
-    bool ShouldWait() override {
-        return true;
-    }
-
-    void Acquire() override {
-        ASSERT_MSG(!ShouldWait(), "object unavailable!");
-    }
-};
-}

src/core/hle/kernel/client_port.cpp

@@ -4,12 +4,44 @@
 
 #include "common/assert.h"
 #include "core/hle/kernel/client_port.h"
+#include "core/hle/kernel/client_session.h"
 #include "core/hle/kernel/kernel.h"
 #include "core/hle/kernel/server_port.h"
+#include "core/hle/kernel/server_session.h"
 
 namespace Kernel {
 
 ClientPort::ClientPort() {}
 ClientPort::~ClientPort() {}
 
+ResultVal<SharedPtr<ClientSession>> ClientPort::Connect() {
+    // Note: Threads do not wait for the server endpoint to call
+    // AcceptSession before returning from this call.
+
+    if (active_sessions >= max_sessions) {
+        // TODO(Subv): Return an error code in this situation after session disconnection is
+        // implemented.
+        /*return ResultCode(ErrorDescription::MaxConnectionsReached,
+                          ErrorModule::OS, ErrorSummary::WouldBlock,
+                          ErrorLevel::Temporary);*/
+    }
+    active_sessions++;
+
+    // Create a new session pair, let the created sessions inherit the parent port's HLE handler.
+    auto sessions =
+        ServerSession::CreateSessionPair(server_port->GetName(), server_port->hle_handler);
+    auto client_session = std::get<SharedPtr<ClientSession>>(sessions);
+    auto server_session = std::get<SharedPtr<ServerSession>>(sessions);
+
+    if (server_port->hle_handler)
+        server_port->hle_handler->ClientConnected(server_session);
+
+    server_port->pending_sessions.push_back(std::move(server_session));
+
+    // Wake the threads waiting on the ServerPort
+    server_port->WakeupAllWaitingThreads();
+
+    return MakeResult<SharedPtr<ClientSession>>(std::move(client_session));
+}
+
 } // namespace

src/core/hle/kernel/client_port.h

@@ -11,8 +11,9 @@
 namespace Kernel {
 
 class ServerPort;
+class ClientSession;
 
-class ClientPort : public Object {
+class ClientPort final : public Object {
 public:
     friend class ServerPort;
     std::string GetTypeName() const override {
@@ -27,12 +28,20 @@ public:
         return HANDLE_TYPE;
     }
 
+    /**
+     * Creates a new Session pair, adds the created ServerSession to the associated ServerPort's
+     * list of pending sessions, and signals the ServerPort, causing any threads
+     * waiting on it to awake.
+     * @returns ClientSession The client endpoint of the created Session pair, or error code.
+     */
+    ResultVal<SharedPtr<ClientSession>> Connect();
+
     SharedPtr<ServerPort> server_port; ///< ServerPort associated with this client port.
     u32 max_sessions;    ///< Maximum number of simultaneous sessions the port can have
     u32 active_sessions; ///< Number of currently open sessions to this port
     std::string name;    ///< Name of client port (optional)
 
-protected:
+private:
     ClientPort();
     ~ClientPort() override;
 };

src/core/hle/kernel/client_session.cpp

@@ -0,0 +1,40 @@
+// Copyright 2016 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include "common/assert.h"
+
+#include "core/hle/kernel/client_session.h"
+#include "core/hle/kernel/server_session.h"
+
+namespace Kernel {
+
+ClientSession::ClientSession() = default;
+ClientSession::~ClientSession() {
+    // This destructor will be called automatically when the last ClientSession handle is closed by
+    // the emulated application.
+
+    if (server_session->hle_handler)
+        server_session->hle_handler->ClientDisconnected(server_session);
+
+    // TODO(Subv): If the session is still open, set the connection status to 2 (Closed by client),
+    // wake up all the ServerSession's waiting threads and set the WaitSynchronization result to
+    // 0xC920181A.
+}
+
+ResultVal<SharedPtr<ClientSession>> ClientSession::Create(ServerSession* server_session,
+                                                          std::string name) {
+    SharedPtr<ClientSession> client_session(new ClientSession);
+
+    client_session->name = std::move(name);
+    client_session->server_session = server_session;
+    client_session->session_status = SessionStatus::Open;
+    return MakeResult<SharedPtr<ClientSession>>(std::move(client_session));
+}
+
+ResultCode ClientSession::SendSyncRequest() {
+    // Signal the server session that new data is available
+    return server_session->HandleSyncRequest();
+}
+
+} // namespace

src/core/hle/kernel/client_session.h

@@ -0,0 +1,65 @@
+// Copyright 2016 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <memory>
+#include <string>
+
+#include "common/common_types.h"
+
+#include "core/hle/kernel/kernel.h"
+
+namespace Kernel {
+
+class ServerSession;
+
+enum class SessionStatus {
+    Open = 1,
+    ClosedByClient = 2,
+    ClosedBYServer = 3,
+};
+
+class ClientSession final : public Object {
+public:
+    friend class ServerSession;
+
+    std::string GetTypeName() const override {
+        return "ClientSession";
+    }
+
+    std::string GetName() const override {
+        return name;
+    }
+
+    static const HandleType HANDLE_TYPE = HandleType::ClientSession;
+    HandleType GetHandleType() const override {
+        return HANDLE_TYPE;
+    }
+
+    /**
+     * Sends an SyncRequest from the current emulated thread.
+     * @return ResultCode of the operation.
+     */
+    ResultCode SendSyncRequest();
+
+    std::string name;              ///< Name of client port (optional)
+    ServerSession* server_session; ///< The server session associated with this client session.
+    SessionStatus session_status;  ///< The session's current status.
+
+private:
+    ClientSession();
+    ~ClientSession() override;
+
+    /**
+     * Creates a client session.
+     * @param server_session The server session associated with this client session
+     * @param name Optional name of client session
+     * @return The created client session
+     */
+    static ResultVal<SharedPtr<ClientSession>> Create(ServerSession* server_session,
+                                                      std::string name = "Unknown");
+};
+
+} // namespace

src/core/hle/kernel/kernel.h

@@ -31,22 +31,21 @@ enum KernelHandle : Handle {
 };
 
 enum class HandleType : u32 {
-    Unknown = 0,
-
-    Session = 2,
-    Event = 3,
-    Mutex = 4,
-    SharedMemory = 5,
-    Redirection = 6,
-    Thread = 7,
-    Process = 8,
-    AddressArbiter = 9,
-    Semaphore = 10,
-    Timer = 11,
-    ResourceLimit = 12,
-    CodeSet = 13,
-    ClientPort = 14,
-    ServerPort = 15,
+    Unknown,
+    Event,
+    Mutex,
+    SharedMemory,
+    Thread,
+    Process,
+    AddressArbiter,
+    Semaphore,
+    Timer,
+    ResourceLimit,
+    CodeSet,
+    ClientPort,
+    ServerPort,
+    ClientSession,
+    ServerSession,
 };
 
 enum {
@@ -82,23 +81,23 @@ public:
      */
     bool IsWaitable() const {
         switch (GetHandleType()) {
-        case HandleType::Session:
-        case HandleType::ServerPort:
         case HandleType::Event:
         case HandleType::Mutex:
         case HandleType::Thread:
         case HandleType::Semaphore:
         case HandleType::Timer:
+        case HandleType::ServerPort:
+        case HandleType::ServerSession:
             return true;
 
         case HandleType::Unknown:
         case HandleType::SharedMemory:
-        case HandleType::Redirection:
         case HandleType::Process:
         case HandleType::AddressArbiter:
         case HandleType::ResourceLimit:
         case HandleType::CodeSet:
         case HandleType::ClientPort:
+        case HandleType::ClientSession:
             return false;
         }
     }

src/core/hle/kernel/server_port.cpp

@@ -24,12 +24,14 @@ void ServerPort::Acquire() {
 }
 
 std::tuple<SharedPtr<ServerPort>, SharedPtr<ClientPort>> ServerPort::CreatePortPair(
-    u32 max_sessions, std::string name) {
+    u32 max_sessions, std::string name,
+    std::shared_ptr<Service::SessionRequestHandler> hle_handler) {
 
     SharedPtr<ServerPort> server_port(new ServerPort);
     SharedPtr<ClientPort> client_port(new ClientPort);
 
     server_port->name = name + "_Server";
+    server_port->hle_handler = std::move(hle_handler);
     client_port->name = name + "_Client";
     client_port->server_port = server_port;
     client_port->max_sessions = max_sessions;

src/core/hle/kernel/server_port.h

@@ -4,11 +4,16 @@
 
 #pragma once
 
+#include <memory>
 #include <string>
 #include <tuple>
 #include "common/common_types.h"
 #include "core/hle/kernel/kernel.h"
 
+namespace Service {
+class SessionRequestHandler;
+}
+
 namespace Kernel {
 
 class ClientPort;
@@ -19,10 +24,13 @@ public:
      * Creates a pair of ServerPort and an associated ClientPort.
      * @param max_sessions Maximum number of sessions to the port
      * @param name Optional name of the ports
+     * @param hle_handler Optional HLE handler template for the port,
+     * ServerSessions crated from this port will inherit a reference to this handler.
      * @return The created port tuple
      */
     static std::tuple<SharedPtr<ServerPort>, SharedPtr<ClientPort>> CreatePortPair(
-        u32 max_sessions, std::string name = "UnknownPort");
+        u32 max_sessions, std::string name = "UnknownPort",
+        std::shared_ptr<Service::SessionRequestHandler> hle_handler = nullptr);
 
     std::string GetTypeName() const override {
         return "ServerPort";
@@ -41,6 +49,10 @@ public:
     std::vector<SharedPtr<WaitObject>>
         pending_sessions; ///< ServerSessions waiting to be accepted by the port
 
+    /// This session's HLE request handler template (optional)
+    /// ServerSessions created from this port inherit a reference to this handler.
+    std::shared_ptr<Service::SessionRequestHandler> hle_handler;
+
     bool ShouldWait() override;
     void Acquire() override;
 

src/core/hle/kernel/server_session.cpp

@@ -0,0 +1,79 @@
+// Copyright 2016 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include <tuple>
+
+#include "core/hle/kernel/client_session.h"
+#include "core/hle/kernel/server_session.h"
+#include "core/hle/kernel/thread.h"
+
+namespace Kernel {
+
+ServerSession::ServerSession() = default;
+ServerSession::~ServerSession() {
+    // This destructor will be called automatically when the last ServerSession handle is closed by
+    // the emulated application.
+    // TODO(Subv): Reduce the ClientPort's connection count,
+    // if the session is still open, set the connection status to 3 (Closed by server),
+}
+
+ResultVal<SharedPtr<ServerSession>> ServerSession::Create(
+    std::string name, std::shared_ptr<Service::SessionRequestHandler> hle_handler) {
+    SharedPtr<ServerSession> server_session(new ServerSession);
+
+    server_session->name = std::move(name);
+    server_session->signaled = false;
+    server_session->hle_handler = std::move(hle_handler);
+
+    return MakeResult<SharedPtr<ServerSession>>(std::move(server_session));
+}
+
+bool ServerSession::ShouldWait() {
+    return !signaled;
+}
+
+void ServerSession::Acquire() {
+    ASSERT_MSG(!ShouldWait(), "object unavailable!");
+    signaled = false;
+}
+
+ResultCode ServerSession::HandleSyncRequest() {
+    // The ServerSession received a sync request, this means that there's new data available
+    // from its ClientSession, so wake up any threads that may be waiting on a svcReplyAndReceive or
+    // similar.
+
+    // If this ServerSession has an associated HLE handler, forward the request to it.
+    if (hle_handler != nullptr) {
+        // Attempt to translate the incoming request's command buffer.
+        ResultCode result = TranslateHLERequest(this);
+        if (result.IsError())
+            return result;
+        hle_handler->HandleSyncRequest(SharedPtr<ServerSession>(this));
+        // TODO(Subv): Translate the response command buffer.
+    }
+
+    // If this ServerSession does not have an HLE implementation, just wake up the threads waiting
+    // on it.
+    signaled = true;
+    WakeupAllWaitingThreads();
+    return RESULT_SUCCESS;
+}
+
+ServerSession::SessionPair ServerSession::CreateSessionPair(
+    const std::string& name, std::shared_ptr<Service::SessionRequestHandler> hle_handler) {
+    auto server_session =
+        ServerSession::Create(name + "_Server", std::move(hle_handler)).MoveFrom();
+    // We keep a non-owning pointer to the ServerSession in the ClientSession because we don't want
+    // to prevent the ServerSession's destructor from being called when the emulated
+    // application closes the last ServerSession handle.
+    auto client_session = ClientSession::Create(server_session.get(), name + "_Client").MoveFrom();
+
+    return std::make_tuple(std::move(server_session), std::move(client_session));
+}
+
+ResultCode TranslateHLERequest(ServerSession* server_session) {
+    // TODO(Subv): Implement this function once multiple concurrent processes are supported.
+    return RESULT_SUCCESS;
+}
+}

src/core/hle/kernel/server_session.h

@@ -0,0 +1,94 @@
+// Copyright 2014 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <string>
+#include "common/assert.h"
+#include "common/common_types.h"
+#include "core/hle/kernel/kernel.h"
+#include "core/hle/kernel/thread.h"
+#include "core/hle/result.h"
+#include "core/hle/service/service.h"
+#include "core/memory.h"
+
+namespace Kernel {
+
+class ClientSession;
+
+/**
+ * Kernel object representing the server 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 ClientSession 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.
+ */
+class ServerSession final : public WaitObject {
+public:
+    std::string GetTypeName() const override {
+        return "ServerSession";
+    }
+
+    static const HandleType HANDLE_TYPE = HandleType::ServerSession;
+    HandleType GetHandleType() const override {
+        return HANDLE_TYPE;
+    }
+
+    using SessionPair = std::tuple<SharedPtr<ServerSession>, SharedPtr<ClientSession>>;
+
+    /**
+     * Creates a pair of ServerSession and an associated ClientSession.
+     * @param name Optional name of the ports
+     * @return The created session tuple
+     */
+    static SessionPair CreateSessionPair(
+        const std::string& name = "Unknown",
+        std::shared_ptr<Service::SessionRequestHandler> hle_handler = nullptr);
+
+    /**
+     * Handle a sync request from the emulated application.
+     * @returns ResultCode from the operation.
+     */
+    ResultCode HandleSyncRequest();
+
+    bool ShouldWait() override;
+
+    void Acquire() override;
+
+    std::string name; ///< The name of this session (optional)
+    bool signaled;    ///< Whether there's new data available to this ServerSession
+    std::shared_ptr<Service::SessionRequestHandler>
+        hle_handler; ///< This session's HLE request handler (optional)
+
+private:
+    ServerSession();
+    ~ServerSession() override;
+
+    /**
+     * Creates a server session. The server session can have an optional HLE handler,
+     * which will be invoked to handle the IPC requests that this session receives.
+     * @param name Optional name of the server session.
+     * @param hle_handler Optional HLE handler for this server session.
+     * @return The created server session
+     */
+    static ResultVal<SharedPtr<ServerSession>> Create(
+        std::string name = "Unknown",
+        std::shared_ptr<Service::SessionRequestHandler> hle_handler = nullptr);
+};
+
+/**
+ * Performs command buffer translation for an HLE IPC request.
+ * The command buffer from the ServerSession thread's TLS is copied into a
+ * buffer and all descriptors in the buffer are processed.
+ * TODO(Subv): Implement this function, currently we do not support multiple processes running at
+ * once, but once that is implemented we'll need to properly translate all descriptors
+ * in the command buffer.
+ */
+ResultCode TranslateHLERequest(ServerSession* server_session);
+}

src/core/hle/result.h

@@ -18,6 +18,7 @@ enum class ErrorDescription : u32 {
     Success = 0,
     WrongPermission = 46,
     OS_InvalidBufferDescriptor = 48,
+    MaxConnectionsReached = 52,
     WrongAddress = 53,
     FS_ArchiveNotMounted = 101,
     FS_FileNotFound = 112,

src/core/hle/service/apt/apt.h

@@ -14,6 +14,9 @@ class Interface;
 
 namespace APT {
 
+/// Each APT service can only have up to 2 sessions connected at the same time.
+static const u32 MaxAPTSessions = 2;
+
 /// Holds information about the parameters used in Send/Glance/ReceiveParameter
 struct MessageParameter {
     u32 sender_id = 0;

src/core/hle/service/apt/apt_a.cpp

@@ -102,7 +102,7 @@ const Interface::FunctionInfo FunctionTable[] = {
     {0x01050100, nullptr, "IsTitleAllowed"},
 };
 
-APT_A_Interface::APT_A_Interface() {
+APT_A_Interface::APT_A_Interface() : Interface(MaxAPTSessions) {
     Register(FunctionTable);
 }
 

src/core/hle/service/apt/apt_s.cpp

@@ -102,7 +102,7 @@ const Interface::FunctionInfo FunctionTable[] = {
     {0x01050100, nullptr, "IsTitleAllowed"},
 };
 
-APT_S_Interface::APT_S_Interface() {
+APT_S_Interface::APT_S_Interface() : Interface(MaxAPTSessions) {
     Register(FunctionTable);
 }
 

src/core/hle/service/apt/apt_u.cpp

@@ -99,7 +99,7 @@ const Interface::FunctionInfo FunctionTable[] = {
     {0x01020000, CheckNew3DS, "CheckNew3DS"},
 };
 
-APT_U_Interface::APT_U_Interface() {
+APT_U_Interface::APT_U_Interface() : Interface(MaxAPTSessions) {
     Register(FunctionTable);
 }
 

src/core/hle/service/fs/archive.cpp

@@ -24,6 +24,7 @@
 #include "core/file_sys/directory_backend.h"
 #include "core/file_sys/file_backend.h"
 #include "core/hle/hle.h"
+#include "core/hle/kernel/client_session.h"
 #include "core/hle/result.h"
 #include "core/hle/service/fs/archive.h"
 #include "core/hle/service/fs/fs_user.h"
@@ -93,7 +94,7 @@ File::File(std::unique_ptr<FileSys::FileBackend>&& backend, const FileSys::Path&
 
 File::~File() {}
 
-ResultVal<bool> File::SyncRequest() {
+void File::HandleSyncRequest(Kernel::SharedPtr<Kernel::ServerSession> server_session) {
     u32* cmd_buff = Kernel::GetCommandBuffer();
     FileCommand cmd = static_cast<FileCommand>(cmd_buff[0]);
     switch (cmd) {
@@ -116,7 +117,7 @@ ResultVal<bool> File::SyncRequest() {
         ResultVal<size_t> read = backend->Read(offset, data.size(), data.data());
         if (read.Failed()) {
             cmd_buff[1] = read.Code().raw;
-            return read.Code();
+            return;
         }
         Memory::WriteBlock(address, data.data(), *read);
         cmd_buff[2] = static_cast<u32>(*read);
@@ -137,7 +138,7 @@ ResultVal<bool> File::SyncRequest() {
         ResultVal<size_t> written = backend->Write(offset, data.size(), flush != 0, data.data());
         if (written.Failed()) {
             cmd_buff[1] = written.Code().raw;
-            return written.Code();
+            return;
         }
         cmd_buff[2] = static_cast<u32>(*written);
         break;
@@ -173,7 +174,11 @@ ResultVal<bool> File::SyncRequest() {
 
     case FileCommand::OpenLinkFile: {
         LOG_WARNING(Service_FS, "(STUBBED) File command OpenLinkFile %s", GetName().c_str());
-        cmd_buff[3] = Kernel::g_handle_table.Create(this).ValueOr(INVALID_HANDLE);
+        auto sessions = Kernel::ServerSession::CreateSessionPair(GetName(), shared_from_this());
+        ClientConnected(std::get<Kernel::SharedPtr<Kernel::ServerSession>>(sessions));
+        cmd_buff[3] = Kernel::g_handle_table
+                          .Create(std::get<Kernel::SharedPtr<Kernel::ClientSession>>(sessions))
+                          .ValueOr(INVALID_HANDLE);
         break;
     }
 
@@ -194,10 +199,9 @@ ResultVal<bool> File::SyncRequest() {
         LOG_ERROR(Service_FS, "Unknown command=0x%08X!", cmd);
         ResultCode error = UnimplementedFunction(ErrorModule::FS);
         cmd_buff[1] = error.raw; // TODO(Link Mauve): use the correct error code for that.
-        return error;
+        return;
     }
     cmd_buff[1] = RESULT_SUCCESS.raw; // No error
-    return MakeResult<bool>(false);
 }
 
 Directory::Directory(std::unique_ptr<FileSys::DirectoryBackend>&& backend,
@@ -206,11 +210,10 @@ Directory::Directory(std::unique_ptr<FileSys::DirectoryBackend>&& backend,
 
 Directory::~Directory() {}
 
-ResultVal<bool> Directory::SyncRequest() {
+void Directory::HandleSyncRequest(Kernel::SharedPtr<Kernel::ServerSession> server_session) {
     u32* cmd_buff = Kernel::GetCommandBuffer();
     DirectoryCommand cmd = static_cast<DirectoryCommand>(cmd_buff[0]);
     switch (cmd) {
-
     // Read from directory...
     case DirectoryCommand::Read: {
         u32 count = cmd_buff[1];
@@ -237,10 +240,9 @@ ResultVal<bool> Directory::SyncRequest() {
         LOG_ERROR(Service_FS, "Unknown command=0x%08X!", cmd);
         ResultCode error = UnimplementedFunction(ErrorModule::FS);
         cmd_buff[1] = error.raw; // TODO(Link Mauve): use the correct error code for that.
-        return MakeResult<bool>(false);
+        return;
     }
     cmd_buff[1] = RESULT_SUCCESS.raw; // No error
-    return MakeResult<bool>(false);
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
@@ -307,9 +309,9 @@ ResultCode RegisterArchiveType(std::unique_ptr<FileSys::ArchiveFactory>&& factor
     return RESULT_SUCCESS;
 }
 
-ResultVal<Kernel::SharedPtr<File>> OpenFileFromArchive(ArchiveHandle archive_handle,
-                                                       const FileSys::Path& path,
-                                                       const FileSys::Mode mode) {
+ResultVal<std::shared_ptr<File>> OpenFileFromArchive(ArchiveHandle archive_handle,
+                                                     const FileSys::Path& path,
+                                                     const FileSys::Mode mode) {
     ArchiveBackend* archive = GetArchive(archive_handle);
     if (archive == nullptr)
         return ERR_INVALID_ARCHIVE_HANDLE;
@@ -318,8 +320,8 @@ ResultVal<Kernel::SharedPtr<File>> OpenFileFromArchive(ArchiveHandle archive_han
     if (backend.Failed())
         return backend.Code();
 
-    auto file = Kernel::SharedPtr<File>(new File(backend.MoveFrom(), path));
-    return MakeResult<Kernel::SharedPtr<File>>(std::move(file));
+    auto file = std::shared_ptr<File>(new File(backend.MoveFrom(), path));
+    return MakeResult<std::shared_ptr<File>>(std::move(file));
 }
 
 ResultCode DeleteFileFromArchive(ArchiveHandle archive_handle, const FileSys::Path& path) {
@@ -398,8 +400,8 @@ ResultCode RenameDirectoryBetweenArchives(ArchiveHandle src_archive_handle,
     }
 }
 
-ResultVal<Kernel::SharedPtr<Directory>> OpenDirectoryFromArchive(ArchiveHandle archive_handle,
-                                                                 const FileSys::Path& path) {
+ResultVal<std::shared_ptr<Directory>> OpenDirectoryFromArchive(ArchiveHandle archive_handle,
+                                                               const FileSys::Path& path) {
     ArchiveBackend* archive = GetArchive(archive_handle);
     if (archive == nullptr)
         return ERR_INVALID_ARCHIVE_HANDLE;
@@ -408,8 +410,8 @@ ResultVal<Kernel::SharedPtr<Directory>> OpenDirectoryFromArchive(ArchiveHandle a
     if (backend.Failed())
         return backend.Code();
 
-    auto directory = Kernel::SharedPtr<Directory>(new Directory(backend.MoveFrom(), path));
-    return MakeResult<Kernel::SharedPtr<Directory>>(std::move(directory));
+    auto directory = std::shared_ptr<Directory>(new Directory(backend.MoveFrom(), path));
+    return MakeResult<std::shared_ptr<Directory>>(std::move(directory));
 }
 
 ResultVal<u64> GetFreeBytesInArchive(ArchiveHandle archive_handle) {

src/core/hle/service/fs/archive.h

@@ -8,7 +8,7 @@
 #include <string>
 #include "common/common_types.h"
 #include "core/file_sys/archive_backend.h"
-#include "core/hle/kernel/session.h"
+#include "core/hle/kernel/server_session.h"
 #include "core/hle/result.h"
 
 namespace FileSys {
@@ -43,33 +43,37 @@ enum class MediaType : u32 { NAND = 0, SDMC = 1, GameCard = 2 };
 
 typedef u64 ArchiveHandle;
 
-class File : public Kernel::Session {
+class File final : public SessionRequestHandler, public std::enable_shared_from_this<File> {
 public:
     File(std::unique_ptr<FileSys::FileBackend>&& backend, const FileSys::Path& path);
     ~File();
 
-    std::string GetName() const override {
+    std::string GetName() const {
         return "Path: " + path.DebugStr();
     }
-    ResultVal<bool> SyncRequest() override;
 
     FileSys::Path path; ///< Path of the file
     u32 priority;       ///< Priority of the file. TODO(Subv): Find out what this means
     std::unique_ptr<FileSys::FileBackend> backend; ///< File backend interface
+
+protected:
+    void HandleSyncRequest(Kernel::SharedPtr<Kernel::ServerSession> server_session) override;
 };
 
-class Directory : public Kernel::Session {
+class Directory final : public SessionRequestHandler {
 public:
     Directory(std::unique_ptr<FileSys::DirectoryBackend>&& backend, const FileSys::Path& path);
     ~Directory();
 
-    std::string GetName() const override {
+    std::string GetName() const {
         return "Directory: " + path.DebugStr();
     }
-    ResultVal<bool> SyncRequest() override;
 
     FileSys::Path path;                                 ///< Path of the directory
     std::unique_ptr<FileSys::DirectoryBackend> backend; ///< File backend interface
+
+protected:
+    void HandleSyncRequest(Kernel::SharedPtr<Kernel::ServerSession> server_session) override;
 };
 
 /**
@@ -99,11 +103,11 @@ ResultCode RegisterArchiveType(std::unique_ptr<FileSys::ArchiveFactory>&& factor
  * @param archive_handle Handle to an open Archive object
  * @param path Path to the File inside of the Archive
  * @param mode Mode under which to open the File
- * @return The opened File object as a Session
+ * @return The opened File object
  */
-ResultVal<Kernel::SharedPtr<File>> OpenFileFromArchive(ArchiveHandle archive_handle,
-                                                       const FileSys::Path& path,
-                                                       const FileSys::Mode mode);
+ResultVal<std::shared_ptr<File>> OpenFileFromArchive(ArchiveHandle archive_handle,
+                                                     const FileSys::Path& path,
+                                                     const FileSys::Mode mode);
 
 /**
  * Delete a File from an Archive
@@ -178,10 +182,10 @@ ResultCode RenameDirectoryBetweenArchives(ArchiveHandle src_archive_handle,
  * Open a Directory from an Archive
  * @param archive_handle Handle to an open Archive object
  * @param path Path to the Directory inside of the Archive
- * @return The opened Directory object as a Session
+ * @return The opened Directory object
  */
-ResultVal<Kernel::SharedPtr<Directory>> OpenDirectoryFromArchive(ArchiveHandle archive_handle,
-                                                                 const FileSys::Path& path);
+ResultVal<std::shared_ptr<Directory>> OpenDirectoryFromArchive(ArchiveHandle archive_handle,
+                                                               const FileSys::Path& path);
 
 /**
  * Get the free space in an Archive

src/core/hle/service/fs/fs_user.cpp

@@ -8,6 +8,7 @@
 #include "common/logging/log.h"
 #include "common/scope_exit.h"
 #include "common/string_util.h"
+#include "core/hle/kernel/client_session.h"
 #include "core/hle/result.h"
 #include "core/hle/service/fs/archive.h"
 #include "core/hle/service/fs/fs_user.h"
@@ -17,7 +18,7 @@
 // Namespace FS_User
 
 using Kernel::SharedPtr;
-using Kernel::Session;
+using Kernel::ServerSession;
 
 namespace Service {
 namespace FS {
@@ -67,10 +68,16 @@ static void OpenFile(Service::Interface* self) {
     LOG_DEBUG(Service_FS, "path=%s, mode=%u attrs=%u", file_path.DebugStr().c_str(), mode.hex,
               attributes);
 
-    ResultVal<SharedPtr<File>> file_res = OpenFileFromArchive(archive_handle, file_path, mode);
+    ResultVal<std::shared_ptr<File>> file_res =
+        OpenFileFromArchive(archive_handle, file_path, mode);
     cmd_buff[1] = file_res.Code().raw;
     if (file_res.Succeeded()) {
-        cmd_buff[3] = Kernel::g_handle_table.Create(*file_res).MoveFrom();
+        std::shared_ptr<File> file = *file_res;
+        auto sessions = ServerSession::CreateSessionPair(file->GetName(), file);
+        file->ClientConnected(std::get<Kernel::SharedPtr<Kernel::ServerSession>>(sessions));
+        cmd_buff[3] = Kernel::g_handle_table
+                          .Create(std::get<Kernel::SharedPtr<Kernel::ClientSession>>(sessions))
+                          .MoveFrom();
     } else {
         cmd_buff[3] = 0;
         LOG_ERROR(Service_FS, "failed to get a handle for file %s", file_path.DebugStr().c_str());
@@ -127,10 +134,16 @@ static void OpenFileDirectly(Service::Interface* self) {
     }
     SCOPE_EXIT({ CloseArchive(*archive_handle); });
 
-    ResultVal<SharedPtr<File>> file_res = OpenFileFromArchive(*archive_handle, file_path, mode);
+    ResultVal<std::shared_ptr<File>> file_res =
+        OpenFileFromArchive(*archive_handle, file_path, mode);
     cmd_buff[1] = file_res.Code().raw;
     if (file_res.Succeeded()) {
-        cmd_buff[3] = Kernel::g_handle_table.Create(*file_res).MoveFrom();
+        std::shared_ptr<File> file = *file_res;
+        auto sessions = ServerSession::CreateSessionPair(file->GetName(), file);
+        file->ClientConnected(std::get<Kernel::SharedPtr<Kernel::ServerSession>>(sessions));
+        cmd_buff[3] = Kernel::g_handle_table
+                          .Create(std::get<Kernel::SharedPtr<Kernel::ClientSession>>(sessions))
+                          .MoveFrom();
     } else {
         cmd_buff[3] = 0;
         LOG_ERROR(Service_FS, "failed to get a handle for file %s mode=%u attributes=%u",
@@ -388,10 +401,16 @@ static void OpenDirectory(Service::Interface* self) {
     LOG_DEBUG(Service_FS, "type=%u size=%u data=%s", static_cast<u32>(dirname_type), dirname_size,
               dir_path.DebugStr().c_str());
 
-    ResultVal<SharedPtr<Directory>> dir_res = OpenDirectoryFromArchive(archive_handle, dir_path);
+    ResultVal<std::shared_ptr<Directory>> dir_res =
+        OpenDirectoryFromArchive(archive_handle, dir_path);
     cmd_buff[1] = dir_res.Code().raw;
     if (dir_res.Succeeded()) {
-        cmd_buff[3] = Kernel::g_handle_table.Create(*dir_res).MoveFrom();
+        std::shared_ptr<Directory> directory = *dir_res;
+        auto sessions = ServerSession::CreateSessionPair(directory->GetName(), directory);
+        directory->ClientConnected(std::get<Kernel::SharedPtr<Kernel::ServerSession>>(sessions));
+        cmd_buff[3] = Kernel::g_handle_table
+                          .Create(std::get<Kernel::SharedPtr<Kernel::ClientSession>>(sessions))
+                          .MoveFrom();
     } else {
         LOG_ERROR(Service_FS, "failed to get a handle for directory type=%d size=%d data=%s",
                   dirname_type, dirname_size, dir_path.DebugStr().c_str());

src/core/hle/service/service.cpp

@@ -2,8 +2,12 @@
 // Licensed under GPLv2 or any later version
 // Refer to the license.txt file included.
 
+#include <boost/range/algorithm_ext/erase.hpp>
+
 #include "common/logging/log.h"
 #include "common/string_util.h"
+
+#include "core/hle/kernel/server_port.h"
 #include "core/hle/service/ac_u.h"
 #include "core/hle/service/act_a.h"
 #include "core/hle/service/act_u.h"
@@ -44,8 +48,8 @@
 
 namespace Service {
 
-std::unordered_map<std::string, Kernel::SharedPtr<Interface>> g_kernel_named_ports;
-std::unordered_map<std::string, Kernel::SharedPtr<Interface>> g_srv_services;
+std::unordered_map<std::string, Kernel::SharedPtr<Kernel::ClientPort>> g_kernel_named_ports;
+std::unordered_map<std::string, Kernel::SharedPtr<Kernel::ClientPort>> g_srv_services;
 
 /**
  * Creates a function string for logging, complete with the name (or header code, depending
@@ -64,7 +68,23 @@ static std::string MakeFunctionString(const char* name, const char* port_name,
     return function_string;
 }
 
-ResultVal<bool> Interface::SyncRequest() {
+void SessionRequestHandler::ClientConnected(
+    Kernel::SharedPtr<Kernel::ServerSession> server_session) {
+    connected_sessions.push_back(server_session);
+}
+
+void SessionRequestHandler::ClientDisconnected(
+    Kernel::SharedPtr<Kernel::ServerSession> server_session) {
+    boost::range::remove_erase(connected_sessions, server_session);
+}
+
+Interface::Interface(u32 max_sessions) : max_sessions(max_sessions) {}
+Interface::~Interface() = default;
+
+void Interface::HandleSyncRequest(Kernel::SharedPtr<Kernel::ServerSession> server_session) {
+    // TODO(Subv): Make use of the server_session in the HLE service handlers to distinguish which
+    // session triggered each command.
+
     u32* cmd_buff = Kernel::GetCommandBuffer();
     auto itr = m_functions.find(cmd_buff[0]);
 
@@ -78,14 +98,12 @@ ResultVal<bool> Interface::SyncRequest() {
 
         // TODO(bunnei): Hack - ignore error
         cmd_buff[1] = 0;
-        return MakeResult<bool>(false);
+        return;
     }
     LOG_TRACE(Service, "%s",
               MakeFunctionString(itr->second.name, GetPortName().c_str(), cmd_buff).c_str());
 
     itr->second.func(this);
-
-    return MakeResult<bool>(false); // TODO: Implement return from actual function
 }
 
 void Interface::Register(const FunctionInfo* functions, size_t n) {
@@ -100,11 +118,19 @@ void Interface::Register(const FunctionInfo* functions, size_t n) {
 // Module interface
 
 static void AddNamedPort(Interface* interface_) {
-    g_kernel_named_ports.emplace(interface_->GetPortName(), interface_);
+    auto ports =
+        Kernel::ServerPort::CreatePortPair(interface_->GetMaxSessions(), interface_->GetPortName(),
+                                           std::shared_ptr<Interface>(interface_));
+    auto client_port = std::get<Kernel::SharedPtr<Kernel::ClientPort>>(ports);
+    g_kernel_named_ports.emplace(interface_->GetPortName(), std::move(client_port));
 }
 
 void AddService(Interface* interface_) {
-    g_srv_services.emplace(interface_->GetPortName(), interface_);
+    auto ports =
+        Kernel::ServerPort::CreatePortPair(interface_->GetMaxSessions(), interface_->GetPortName(),
+                                           std::shared_ptr<Interface>(interface_));
+    auto client_port = std::get<Kernel::SharedPtr<Kernel::ClientPort>>(ports);
+    g_srv_services.emplace(interface_->GetPortName(), std::move(client_port));
 }
 
 /// Initialize ServiceManager

src/core/hle/service/service.h

@@ -9,8 +9,15 @@
 #include <unordered_map>
 #include <boost/container/flat_map.hpp>
 #include "common/common_types.h"
-#include "core/hle/kernel/session.h"
+#include "core/hle/ipc.h"
+#include "core/hle/kernel/client_port.h"
+#include "core/hle/kernel/thread.h"
 #include "core/hle/result.h"
+#include "core/memory.h"
+
+namespace Kernel {
+class ServerSession;
+}
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 // Namespace Service
@@ -18,14 +25,63 @@
 namespace Service {
 
 static const int kMaxPortSize = 8; ///< Maximum size of a port name (8 characters)
+/// Arbitrary default number of maximum connections to an HLE service.
+static const u32 DefaultMaxSessions = 10;
+
+/**
+ * Interface implemented by HLE Session handlers.
+ * This can be provided to a ServerSession in order to hook into several relevant events
+ * (such as a new connection or a SyncRequest) so they can be implemented in the emulator.
+ */
+class SessionRequestHandler {
+public:
+    /**
+     * 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): Use a wrapper structure to hold all the information relevant to
+     * this request (ServerSession, Originator thread, Translated command buffer, etc).
+     * @returns ResultCode the result code of the translate operation.
+     */
+    virtual void HandleSyncRequest(Kernel::SharedPtr<Kernel::ServerSession> server_session) = 0;
+
+    /**
+     * Signals that a client has just connected to this HLE handler and keeps the
+     * associated ServerSession alive for the duration of the connection.
+     * @param server_session Owning pointer to the ServerSession associated with the connection.
+     */
+    void ClientConnected(Kernel::SharedPtr<Kernel::ServerSession> server_session);
+
+    /**
+     * Signals that a client has just disconnected from this HLE handler and releases the
+     * associated ServerSession.
+     * @param server_session ServerSession associated with the connection.
+     */
+    void ClientDisconnected(Kernel::SharedPtr<Kernel::ServerSession> server_session);
 
-/// Interface to a CTROS service
-class Interface : public Kernel::Session {
-    // TODO(yuriks): An "Interface" being a Kernel::Object is mostly non-sense. Interface should be
-    // just something that encapsulates a session and acts as a helper to implement service
-    // processes.
+protected:
+    /// List of sessions that are connected to this handler.
+    /// A ServerSession whose server endpoint is an HLE implementation is kept alive by this list
+    // for the duration of the connection.
+    std::vector<Kernel::SharedPtr<Kernel::ServerSession>> connected_sessions;
+};
+
+/**
+ * Framework for implementing HLE service handlers which dispatch incoming SyncRequests based on a
+ * table mapping header ids to handler functions.
+ */
+class Interface : public SessionRequestHandler {
 public:
-    std::string GetName() const override {
+    /**
+     * Creates an HLE interface with the specified max sessions.
+     * @param max_sessions Maximum number of sessions that can be
+     * connected to this service at the same time.
+     */
+    Interface(u32 max_sessions = DefaultMaxSessions);
+
+    virtual ~Interface();
+
+    std::string GetName() const {
         return GetPortName();
     }
 
@@ -33,6 +89,15 @@ public:
         version.raw = raw_version;
     }
 
+    /**
+     * Gets the maximum allowed number of sessions that can be connected to this service
+     * at the same time.
+     * @returns The maximum number of connections allowed.
+     */
+    u32 GetMaxSessions() const {
+        return max_sessions;
+    }
+
     typedef void (*Function)(Interface*);
 
     struct FunctionInfo {
@@ -49,9 +114,9 @@ public:
         return "[UNKNOWN SERVICE PORT]";
     }
 
-    ResultVal<bool> SyncRequest() override;
-
 protected:
+    void HandleSyncRequest(Kernel::SharedPtr<Kernel::ServerSession> server_session) override;
+
     /**
      * Registers the functions in the service
      */
@@ -71,6 +136,7 @@ protected:
     } version = {};
 
 private:
+    u32 max_sessions; ///< Maximum number of concurrent sessions that this service can handle.
     boost::container::flat_map<u32, FunctionInfo> m_functions;
 };
 
@@ -81,9 +147,9 @@ 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<Interface>> g_kernel_named_ports;
+extern std::unordered_map<std::string, Kernel::SharedPtr<Kernel::ClientPort>> g_kernel_named_ports;
 /// Map of services registered with the "srv:" service, retrieved using GetServiceHandle.
-extern std::unordered_map<std::string, Kernel::SharedPtr<Interface>> g_srv_services;
+extern std::unordered_map<std::string, Kernel::SharedPtr<Kernel::ClientPort>> g_srv_services;
 
 /// Adds a service to the services table
 void AddService(Interface* interface_);

src/core/hle/service/soc_u.cpp

@@ -11,7 +11,7 @@
 #include "common/common_types.h"
 #include "common/logging/log.h"
 #include "common/scope_exit.h"
-#include "core/hle/kernel/session.h"
+#include "core/hle/kernel/server_session.h"
 #include "core/hle/result.h"
 #include "core/hle/service/soc_u.h"
 #include "core/memory.h"

src/core/hle/service/srv.cpp

@@ -2,9 +2,13 @@
 // Licensed under GPLv2 or any later version
 // Refer to the license.txt file included.
 
+#include <tuple>
+
 #include "common/common_types.h"
 #include "common/logging/log.h"
+#include "core/hle/kernel/client_session.h"
 #include "core/hle/kernel/event.h"
+#include "core/hle/kernel/server_session.h"
 #include "core/hle/service/srv.h"
 
 namespace Service {
@@ -79,7 +83,15 @@ static void GetServiceHandle(Interface* self) {
     auto it = Service::g_srv_services.find(port_name);
 
     if (it != Service::g_srv_services.end()) {
-        cmd_buff[3] = Kernel::g_handle_table.Create(it->second).MoveFrom();
+        auto client_port = it->second;
+
+        auto client_session = client_port->Connect();
+        res = client_session.Code();
+
+        if (client_session.Succeeded()) {
+            // Return the client session
+            cmd_buff[3] = Kernel::g_handle_table.Create(*client_session).MoveFrom();
+        }
         LOG_TRACE(Service_SRV, "called port=%s, handle=0x%08X", port_name.c_str(), cmd_buff[3]);
     } else {
         LOG_ERROR(Service_SRV, "(UNIMPLEMENTED) called port=%s", port_name.c_str());

src/core/hle/svc.cpp

@@ -13,6 +13,7 @@
 #include "core/hle/function_wrappers.h"
 #include "core/hle/kernel/address_arbiter.h"
 #include "core/hle/kernel/client_port.h"
+#include "core/hle/kernel/client_session.h"
 #include "core/hle/kernel/event.h"
 #include "core/hle/kernel/memory.h"
 #include "core/hle/kernel/mutex.h"
@@ -20,6 +21,7 @@
 #include "core/hle/kernel/resource_limit.h"
 #include "core/hle/kernel/semaphore.h"
 #include "core/hle/kernel/server_port.h"
+#include "core/hle/kernel/server_session.h"
 #include "core/hle/kernel/shared_memory.h"
 #include "core/hle/kernel/thread.h"
 #include "core/hle/kernel/timer.h"
@@ -222,20 +224,29 @@ static ResultCode ConnectToPort(Handle* out_handle, const char* port_name) {
         return ERR_NOT_FOUND;
     }
 
-    CASCADE_RESULT(*out_handle, Kernel::g_handle_table.Create(it->second));
+    auto client_port = it->second;
+
+    SharedPtr<Kernel::ClientSession> client_session;
+    CASCADE_RESULT(client_session, client_port->Connect());
+
+    // Return the client session
+    CASCADE_RESULT(*out_handle, Kernel::g_handle_table.Create(client_session));
     return RESULT_SUCCESS;
 }
 
-/// Synchronize to an OS service
+/// Makes a blocking IPC call to an OS service.
 static ResultCode SendSyncRequest(Handle handle) {
-    SharedPtr<Kernel::Session> session = Kernel::g_handle_table.Get<Kernel::Session>(handle);
+    SharedPtr<Kernel::ClientSession> session =
+        Kernel::g_handle_table.Get<Kernel::ClientSession>(handle);
     if (session == nullptr) {
         return ERR_INVALID_HANDLE;
     }
 
     LOG_TRACE(Kernel_SVC, "called handle=0x%08X(%s)", handle, session->GetName().c_str());
 
-    return session->SyncRequest().Code();
+    // TODO(Subv): svcSendSyncRequest should put the caller thread to sleep while the server
+    // responds and cause a reschedule.
+    return session->SendSyncRequest();
 }
 
 /// Close a handle