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

All handles obtained via srv::GetServiceHandle or svcConnectToPort are references to ClientSessions.
Service modules will wait on the counterpart of those ClientSessions (Called ServerSessions) using svcReplyAndReceive or svcWaitSynchronization[1|N], and will be awoken when a SyncRequest is performed.

HLE Interfaces are now ClientPorts which override the HandleSyncRequest virtual member function to perform command handling immediately.

7 files changed, 62 insertions, 27 deletions

diff --git a/src/core/hle/service/fs/archive.cpp b/src/core/hle/service/fs/archive.cpp
index 4c29784e8..da009df91 100644
--- a/src/core/hle/service/fs/archive.cpp
+++ b/src/core/hle/service/fs/archive.cpp
@@ -92,7 +92,7 @@ File::File(std::unique_ptr<FileSys::FileBackend>&& backend, const FileSys::Path&
 
 File::~File() {}
 
-ResultVal<bool> File::SyncRequest() {
+ResultCode File::HandleSyncRequest() {
     u32* cmd_buff = Kernel::GetCommandBuffer();
     FileCommand cmd = static_cast<FileCommand>(cmd_buff[0]);
     switch (cmd) {
@@ -193,10 +193,10 @@ 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 ServerSession::HandleSyncRequest();
     }
     cmd_buff[1] = RESULT_SUCCESS.raw; // No error
-    return MakeResult<bool>(false);
+    return ServerSession::HandleSyncRequest();
 }
 
 Directory::Directory(std::unique_ptr<FileSys::DirectoryBackend>&& backend,
@@ -205,7 +205,7 @@ Directory::Directory(std::unique_ptr<FileSys::DirectoryBackend>&& backend,
 
 Directory::~Directory() {}
 
-ResultVal<bool> Directory::SyncRequest() {
+ResultCode Directory::HandleSyncRequest() {
     u32* cmd_buff = Kernel::GetCommandBuffer();
     DirectoryCommand cmd = static_cast<DirectoryCommand>(cmd_buff[0]);
     switch (cmd) {
@@ -236,10 +236,10 @@ 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 ServerSession::HandleSyncRequest();
     }
     cmd_buff[1] = RESULT_SUCCESS.raw; // No error
-    return MakeResult<bool>(false);
+    return ServerSession::HandleSyncRequest();
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
diff --git a/src/core/hle/service/fs/archive.h b/src/core/hle/service/fs/archive.h
index 21ed9717b..22e659c40 100644
--- a/src/core/hle/service/fs/archive.h
+++ b/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 {
@@ -41,7 +41,7 @@ enum class MediaType : u32 { NAND = 0, SDMC = 1 };
 
 typedef u64 ArchiveHandle;
 
-class File : public Kernel::Session {
+class File : public Kernel::ServerSession {
 public:
     File(std::unique_ptr<FileSys::FileBackend>&& backend, const FileSys::Path& path);
     ~File();
@@ -49,14 +49,15 @@ public:
     std::string GetName() const override {
         return "Path: " + path.DebugStr();
     }
-    ResultVal<bool> SyncRequest() override;
+
+    ResultCode HandleSyncRequest() 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
 };
 
-class Directory : public Kernel::Session {
+class Directory : public Kernel::ServerSession {
 public:
     Directory(std::unique_ptr<FileSys::DirectoryBackend>&& backend, const FileSys::Path& path);
     ~Directory();
@@ -64,7 +65,8 @@ public:
     std::string GetName() const override {
         return "Directory: " + path.DebugStr();
     }
-    ResultVal<bool> SyncRequest() override;
+
+    ResultCode HandleSyncRequest() override;
 
     FileSys::Path path;                                 ///< Path of the directory
     std::unique_ptr<FileSys::DirectoryBackend> backend; ///< File backend interface
diff --git a/src/core/hle/service/fs/fs_user.cpp b/src/core/hle/service/fs/fs_user.cpp
index 9ec17b395..bb78091f9 100644
--- a/src/core/hle/service/fs/fs_user.cpp
+++ b/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 {
@@ -70,7 +71,7 @@ static void OpenFile(Service::Interface* self) {
     ResultVal<SharedPtr<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();
+        cmd_buff[3] = Kernel::g_handle_table.Create((*file_res)->CreateClientSession()).MoveFrom();
     } else {
         cmd_buff[3] = 0;
         LOG_ERROR(Service_FS, "failed to get a handle for file %s", file_path.DebugStr().c_str());
@@ -130,7 +131,7 @@ static void OpenFileDirectly(Service::Interface* self) {
     ResultVal<SharedPtr<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();
+        cmd_buff[3] = Kernel::g_handle_table.Create((*file_res)->CreateClientSession()).MoveFrom();
     } else {
         cmd_buff[3] = 0;
         LOG_ERROR(Service_FS, "failed to get a handle for file %s mode=%u attributes=%u",
@@ -391,7 +392,7 @@ static void OpenDirectory(Service::Interface* self) {
     ResultVal<SharedPtr<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();
+        cmd_buff[3] = Kernel::g_handle_table.Create((*dir_res)->CreateClientSession()).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());
diff --git a/src/core/hle/service/service.cpp b/src/core/hle/service/service.cpp
index ca7eeac8a..f51a042ff 100644
--- a/src/core/hle/service/service.cpp
+++ b/src/core/hle/service/service.cpp
@@ -41,8 +41,8 @@
 
 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
@@ -61,7 +61,7 @@ static std::string MakeFunctionString(const char* name, const char* port_name,
     return function_string;
 }
 
-ResultVal<bool> Interface::SyncRequest() {
+ResultCode Interface::HandleSyncRequest() {
     u32* cmd_buff = Kernel::GetCommandBuffer();
     auto itr = m_functions.find(cmd_buff[0]);
 
@@ -75,14 +75,14 @@ ResultVal<bool> Interface::SyncRequest() {
 
         // TODO(bunnei): Hack - ignore error
         cmd_buff[1] = 0;
-        return MakeResult<bool>(false);
+        return RESULT_SUCCESS;
     }
     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
+    return RESULT_SUCCESS; // TODO: Implement return from actual function, it should fail if the parameter translation fails
 }
 
 void Interface::Register(const FunctionInfo* functions, size_t n) {
@@ -97,10 +97,16 @@ void Interface::Register(const FunctionInfo* functions, size_t n) {
 // Module interface
 
 static void AddNamedPort(Interface* interface_) {
+    interface_->name = interface_->GetPortName();
+    interface_->active_sessions = 0;
+    interface_->max_sessions = interface_->GetMaxSessions();
     g_kernel_named_ports.emplace(interface_->GetPortName(), interface_);
 }
 
 void AddService(Interface* interface_) {
+    interface_->name = interface_->GetPortName();
+    interface_->active_sessions = 0;
+    interface_->max_sessions = interface_->GetMaxSessions();
     g_srv_services.emplace(interface_->GetPortName(), interface_);
 }
 
diff --git a/src/core/hle/service/service.h b/src/core/hle/service/service.h
index 29daacfc4..fd15ad03f 100644
--- a/src/core/hle/service/service.h
+++ b/src/core/hle/service/service.h
@@ -9,7 +9,8 @@
 #include <unordered_map>
 #include <boost/container/flat_map.hpp>
 #include "common/common_types.h"
-#include "core/hle/kernel/session.h"
+#include "core/hle/kernel/client_port.h"
+#include "core/hle/kernel/server_session.h"
 #include "core/hle/result.h"
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
@@ -18,9 +19,10 @@
 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
 
 /// Interface to a CTROS service
-class Interface : public Kernel::Session {
+class Interface : public Kernel::ClientPort {
     // 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.
@@ -33,6 +35,15 @@ public:
         version.raw = raw_version;
     }
 
+    /**
+     * Gets the maximum allowed number of sessions that can be connected to this port at the same time.
+     * It should be overwritten by each service implementation for more fine-grained control.
+     * @returns The maximum number of connections allowed.
+     */
+    virtual u32 GetMaxSessions() { return DefaultMaxSessions; }
+
+    void AddWaitingSession(Kernel::SharedPtr<Kernel::ServerSession> server_session) override { }
+
     typedef void (*Function)(Interface*);
 
     struct FunctionInfo {
@@ -49,7 +60,7 @@ public:
         return "[UNKNOWN SERVICE PORT]";
     }
 
-    ResultVal<bool> SyncRequest() override;
+    ResultCode HandleSyncRequest() override;
 
 protected:
     /**
@@ -81,9 +92,9 @@ 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_);
diff --git a/src/core/hle/service/soc_u.cpp b/src/core/hle/service/soc_u.cpp
index 46b75db25..2e8b2fc00 100644
--- a/src/core/hle/service/soc_u.cpp
+++ b/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"
diff --git a/src/core/hle/service/srv.cpp b/src/core/hle/service/srv.cpp
index b25be413a..eb2e06041 100644
--- a/src/core/hle/service/srv.cpp
+++ b/src/core/hle/service/srv.cpp
@@ -2,8 +2,12 @@
 // 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/service/srv.h"
+#include "core/hle/kernel/client_session.h"
 #include "core/hle/kernel/event.h"
 #include "core/hle/service/srv.h"
 
@@ -81,7 +85,18 @@ static void GetServiceHandle(Service::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;
+
+        // Create a new session pair
+        auto sessions = Kernel::ServerSession::CreateSessionPair(client_port, port_name);
+        auto client_session = std::get<Kernel::SharedPtr<Kernel::ClientSession>>(sessions);
+        auto server_session = std::get<Kernel::SharedPtr<Kernel::ServerSession>>(sessions);
+
+        // Add the server session to the port's queue
+        client_port->AddWaitingSession(server_session);
+
+        // 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());