Merge pull request #2774 from yuriks/hle-handles

Add basic support for IPC translation for HLE services

externals/boost

@@ -1 +1 @@
-Subproject commit 351972396392c97a659b9a02f34ce9269293d21f
+Subproject commit 3abc84abaf63a068cb59a9f9b5675c1947bc6fd9

src/core/hle/ipc.h

@@ -44,6 +44,9 @@ inline u32* GetStaticBuffers(const int offset = 0) {
 
 namespace IPC {
 
+/// Size of the command buffer area, in 32-bit words.
+constexpr size_t COMMAND_BUFFER_LENGTH = 0x100 / sizeof(u32);
+
 // These errors are commonly returned by invalid IPC translations, so alias them here for
 // convenience.
 // TODO(yuriks): These will probably go away once translation is implemented inside the kernel.

src/core/hle/ipc_helpers.h

@@ -4,19 +4,28 @@
 
 #pragma once
 
+#include <array>
+#include <tuple>
+#include <type_traits>
+#include <utility>
 #include "core/hle/ipc.h"
 #include "core/hle/kernel/handle_table.h"
+#include "core/hle/kernel/hle_ipc.h"
 #include "core/hle/kernel/kernel.h"
 
 namespace IPC {
 
 class RequestHelperBase {
 protected:
+    Kernel::HLERequestContext* context = nullptr;
     u32* cmdbuf;
     ptrdiff_t index = 1;
     Header header;
 
 public:
+    RequestHelperBase(Kernel::HLERequestContext& context, Header desired_header)
+        : context(&context), cmdbuf(context.CommandBuffer()), header(desired_header) {}
+
     RequestHelperBase(u32* command_buffer, Header command_header)
         : cmdbuf(command_buffer), header(command_header) {}
 
@@ -51,12 +60,27 @@ public:
 
 class RequestBuilder : public RequestHelperBase {
 public:
+    RequestBuilder(Kernel::HLERequestContext& context, Header command_header)
+        : RequestHelperBase(context, command_header) {
+        // From this point we will start overwriting the existing command buffer, so it's safe to
+        // release all previous incoming Object pointers since they won't be usable anymore.
+        context.ClearIncomingObjects();
+        cmdbuf[0] = header.raw;
+    }
+
+    RequestBuilder(Kernel::HLERequestContext& context, u16 command_id, unsigned normal_params_size,
+                   unsigned translate_params_size)
+        : RequestBuilder(
+              context, Header{MakeHeader(command_id, normal_params_size, translate_params_size)}) {}
+
     RequestBuilder(u32* command_buffer, Header command_header)
         : RequestHelperBase(command_buffer, command_header) {
         cmdbuf[0] = header.raw;
     }
+
     explicit RequestBuilder(u32* command_buffer, u32 command_header)
         : RequestBuilder(command_buffer, Header{command_header}) {}
+
     RequestBuilder(u32* command_buffer, u16 command_id, unsigned normal_params_size,
                    unsigned translate_params_size)
         : RequestBuilder(command_buffer,
@@ -88,6 +112,9 @@ public:
     template <typename... H>
     void PushMoveHandles(H... handles);
 
+    template <typename... O>
+    void PushObjects(Kernel::SharedPtr<O>... pointers);
+
     void PushCurrentPIDHandle();
 
     void PushStaticBuffer(VAddr buffer_vaddr, u32 size, u8 buffer_id);
@@ -153,6 +180,11 @@ inline void RequestBuilder::PushMoveHandles(H... handles) {
     Push(static_cast<Kernel::Handle>(handles)...);
 }
 
+template <typename... O>
+inline void RequestBuilder::PushObjects(Kernel::SharedPtr<O>... pointers) {
+    PushMoveHandles(context->AddOutgoingHandle(std::move(pointers))...);
+}
+
 inline void RequestBuilder::PushCurrentPIDHandle() {
     Push(CallingPidDesc());
     Push(u32(0));
@@ -171,10 +203,21 @@ inline void RequestBuilder::PushMappedBuffer(VAddr buffer_vaddr, u32 size,
 
 class RequestParser : public RequestHelperBase {
 public:
+    RequestParser(Kernel::HLERequestContext& context, Header desired_header)
+        : RequestHelperBase(context, desired_header) {}
+
+    RequestParser(Kernel::HLERequestContext& context, u16 command_id, unsigned normal_params_size,
+                  unsigned translate_params_size)
+        : RequestParser(context,
+                        Header{MakeHeader(command_id, normal_params_size, translate_params_size)}) {
+    }
+
     RequestParser(u32* command_buffer, Header command_header)
         : RequestHelperBase(command_buffer, command_header) {}
+
     explicit RequestParser(u32* command_buffer, u32 command_header)
         : RequestParser(command_buffer, Header{command_header}) {}
+
     RequestParser(u32* command_buffer, u16 command_id, unsigned normal_params_size,
                   unsigned translate_params_size)
         : RequestParser(command_buffer,
@@ -186,6 +229,9 @@ public:
             ValidateHeader();
         Header builderHeader{
             MakeHeader(header.command_id, normal_params_size, translate_params_size)};
+        if (context != nullptr)
+            return {*context, builderHeader};
+        else
             return {cmdbuf, builderHeader};
     }
 
@@ -198,10 +244,52 @@ public:
     template <typename First, typename... Other>
     void Pop(First& first_value, Other&... other_values);
 
+    /// Equivalent to calling `PopHandles<1>()[0]`.
     Kernel::Handle PopHandle();
 
+    /**
+     * Pops a descriptor containing `N` handles. The handles are returned as an array. The
+     * descriptor must contain exactly `N` handles, it is not permitted to, for example, call
+     * PopHandles<1>() twice to read a multi-handle descriptor with 2 handles, or to make a single
+     * PopHandles<2>() call to read 2 single-handle descriptors.
+     */
+    template <unsigned int N>
+    std::array<Kernel::Handle, N> PopHandles();
+
+    /// Convenience wrapper around PopHandles() which assigns the handles to the passed references.
     template <typename... H>
-    void PopHandles(H&... handles);
+    void PopHandles(H&... handles) {
+        std::tie(handles...) = PopHandles<sizeof...(H)>();
+    }
+
+    /// Equivalent to calling `PopGenericObjects<1>()[0]`.
+    Kernel::SharedPtr<Kernel::Object> PopGenericObject();
+
+    /// Equivalent to calling `std::get<0>(PopObjects<T>())`.
+    template <typename T>
+    Kernel::SharedPtr<T> PopObject();
+
+    /**
+     * Pop a descriptor containing `N` handles and resolves them to Kernel::Object pointers. If a
+     * handle is invalid, null is returned for that object instead. The same caveats from
+     * PopHandles() apply regarding `N` matching the number of handles in the descriptor.
+     */
+    template <unsigned int N>
+    std::array<Kernel::SharedPtr<Kernel::Object>, N> PopGenericObjects();
+
+    /**
+     * Resolves handles to Kernel::Objects as in PopGenericsObjects(), but then also casts them to
+     * the passed `T` types, while verifying that the cast is valid. If the type of an object does
+     * not match, null is returned instead.
+     */
+    template <typename... T>
+    std::tuple<Kernel::SharedPtr<T>...> PopObjects();
+
+    /// Convenience wrapper around PopObjects() which assigns the handles to the passed references.
+    template <typename... T>
+    void PopObjects(Kernel::SharedPtr<T>&... pointers) {
+        std::tie(pointers...) = PopObjects<T...>();
+    }
 
     /**
      * @brief Pops the static buffer vaddr
@@ -313,15 +401,54 @@ inline Kernel::Handle RequestParser::PopHandle() {
     return Pop<Kernel::Handle>();
 }
 
-template <typename... H>
-void RequestParser::PopHandles(H&... handles) {
-    const u32 handle_descriptor = Pop<u32>();
-    const int handles_number = sizeof...(H);
-    DEBUG_ASSERT_MSG(IsHandleDescriptor(handle_descriptor),
+template <unsigned int N>
+std::array<Kernel::Handle, N> RequestParser::PopHandles() {
+    u32 handle_descriptor = Pop<u32>();
+    ASSERT_MSG(IsHandleDescriptor(handle_descriptor),
                "Tried to pop handle(s) but the descriptor is not a handle descriptor");
-    DEBUG_ASSERT_MSG(handles_number == HandleNumberFromDesc(handle_descriptor),
+    ASSERT_MSG(N == HandleNumberFromDesc(handle_descriptor),
                "Number of handles doesn't match the descriptor");
-    Pop(static_cast<Kernel::Handle&>(handles)...);
+
+    std::array<Kernel::Handle, N> handles{};
+    for (Kernel::Handle& handle : handles) {
+        handle = Pop<Kernel::Handle>();
+    }
+    return handles;
+}
+
+inline Kernel::SharedPtr<Kernel::Object> RequestParser::PopGenericObject() {
+    Kernel::Handle handle = PopHandle();
+    return context->GetIncomingHandle(handle);
+}
+
+template <typename T>
+Kernel::SharedPtr<T> RequestParser::PopObject() {
+    return Kernel::DynamicObjectCast<T>(PopGenericObject());
+}
+
+template <unsigned int N>
+inline std::array<Kernel::SharedPtr<Kernel::Object>, N> RequestParser::PopGenericObjects() {
+    std::array<Kernel::Handle, N> handles = PopHandles<N>();
+    std::array<Kernel::SharedPtr<Kernel::Object>, N> pointers;
+    for (int i = 0; i < N; ++i) {
+        pointers[i] = context->GetIncomingHandle(handles[i]);
+    }
+    return pointers;
+}
+
+namespace detail {
+template <typename... T, size_t... I>
+std::tuple<Kernel::SharedPtr<T>...> PopObjectsHelper(
+    std::array<Kernel::SharedPtr<Kernel::Object>, sizeof...(T)>&& pointers,
+    std::index_sequence<I...>) {
+    return std::make_tuple(Kernel::DynamicObjectCast<T>(std::move(pointers[I]))...);
+}
+} // namespace detail
+
+template <typename... T>
+inline std::tuple<Kernel::SharedPtr<T>...> RequestParser::PopObjects() {
+    return detail::PopObjectsHelper<T...>(PopGenericObjects<sizeof...(T)>(),
+                                          std::index_sequence_for<T...>{});
 }
 
 inline VAddr RequestParser::PopStaticBuffer(size_t* data_size, bool useStaticBuffersToGetVaddr) {

src/core/hle/kernel/hle_ipc.cpp

@@ -5,8 +5,10 @@
 #include <boost/range/algorithm_ext/erase.hpp>
 #include "common/assert.h"
 #include "common/common_types.h"
+#include "core/hle/kernel/handle_table.h"
 #include "core/hle/kernel/hle_ipc.h"
 #include "core/hle/kernel/kernel.h"
+#include "core/hle/kernel/process.h"
 #include "core/hle/kernel/server_session.h"
 
 namespace Kernel {
@@ -23,4 +25,101 @@ void SessionRequestHandler::ClientDisconnected(SharedPtr<ServerSession> server_s
 
 HLERequestContext::~HLERequestContext() = default;
 
+SharedPtr<Object> HLERequestContext::GetIncomingHandle(u32 id_from_cmdbuf) const {
+    ASSERT(id_from_cmdbuf < request_handles.size());
+    return request_handles[id_from_cmdbuf];
+}
+
+u32 HLERequestContext::AddOutgoingHandle(SharedPtr<Object> object) {
+    request_handles.push_back(std::move(object));
+    return request_handles.size() - 1;
+}
+
+void HLERequestContext::ClearIncomingObjects() {
+    request_handles.clear();
+}
+
+ResultCode HLERequestContext::PopulateFromIncomingCommandBuffer(const u32_le* src_cmdbuf,
+                                                                Process& src_process,
+                                                                HandleTable& src_table) {
+    IPC::Header header{src_cmdbuf[0]};
+
+    size_t untranslated_size = 1u + header.normal_params_size;
+    size_t command_size = untranslated_size + header.translate_params_size;
+    ASSERT(command_size <= IPC::COMMAND_BUFFER_LENGTH); // TODO(yuriks): Return error
+
+    std::copy_n(src_cmdbuf, untranslated_size, cmd_buf.begin());
+
+    size_t i = untranslated_size;
+    while (i < command_size) {
+        u32 descriptor = cmd_buf[i] = src_cmdbuf[i];
+        i += 1;
+
+        switch (IPC::GetDescriptorType(descriptor)) {
+        case IPC::DescriptorType::CopyHandle:
+        case IPC::DescriptorType::MoveHandle: {
+            u32 num_handles = IPC::HandleNumberFromDesc(descriptor);
+            ASSERT(i + num_handles <= command_size); // TODO(yuriks): Return error
+            for (u32 j = 0; j < num_handles; ++j) {
+                Handle handle = src_cmdbuf[i];
+                SharedPtr<Object> object = src_table.GetGeneric(handle);
+                ASSERT(object != nullptr); // TODO(yuriks): Return error
+                if (descriptor == IPC::DescriptorType::MoveHandle) {
+                    src_table.Close(handle);
+                }
+
+                cmd_buf[i++] = AddOutgoingHandle(std::move(object));
+            }
+            break;
+        }
+        case IPC::DescriptorType::CallingPid: {
+            cmd_buf[i++] = src_process.process_id;
+            break;
+        }
+        default:
+            UNIMPLEMENTED_MSG("Unsupported handle translation: 0x%08X", descriptor);
+        }
+    }
+
+    return RESULT_SUCCESS;
+}
+
+ResultCode HLERequestContext::WriteToOutgoingCommandBuffer(u32_le* dst_cmdbuf, Process& dst_process,
+                                                           HandleTable& dst_table) const {
+    IPC::Header header{cmd_buf[0]};
+
+    size_t untranslated_size = 1u + header.normal_params_size;
+    size_t command_size = untranslated_size + header.translate_params_size;
+    ASSERT(command_size <= IPC::COMMAND_BUFFER_LENGTH);
+
+    std::copy_n(cmd_buf.begin(), untranslated_size, dst_cmdbuf);
+
+    size_t i = untranslated_size;
+    while (i < command_size) {
+        u32 descriptor = dst_cmdbuf[i] = cmd_buf[i];
+        i += 1;
+
+        switch (IPC::GetDescriptorType(descriptor)) {
+        case IPC::DescriptorType::CopyHandle:
+        case IPC::DescriptorType::MoveHandle: {
+            // HLE services don't use handles, so we treat both CopyHandle and MoveHandle equally
+            u32 num_handles = IPC::HandleNumberFromDesc(descriptor);
+            ASSERT(i + num_handles <= command_size);
+            for (u32 j = 0; j < num_handles; ++j) {
+                SharedPtr<Object> object = GetIncomingHandle(cmd_buf[i]);
+
+                // TODO(yuriks): Figure out the proper error handling for if this fails
+                Handle handle = dst_table.Create(object).Unwrap();
+                dst_cmdbuf[i++] = handle;
+            }
+            break;
+        }
+        default:
+            UNIMPLEMENTED_MSG("Unsupported handle translation: 0x%08X", descriptor);
+        }
+    }
+
+    return RESULT_SUCCESS;
+}
+
 } // namespace Kernel

src/core/hle/kernel/hle_ipc.h

@@ -4,8 +4,13 @@
 
 #pragma once
 
+#include <array>
 #include <memory>
 #include <vector>
+#include <boost/container/small_vector.hpp>
+#include "common/common_types.h"
+#include "common/swap.h"
+#include "core/hle/ipc.h"
 #include "core/hle/kernel/kernel.h"
 #include "core/hle/kernel/server_session.h"
 
@@ -15,6 +20,9 @@ class ServiceFrameworkBase;
 
 namespace Kernel {
 
+class HandleTable;
+class Process;
+
 /**
  * Interface implemented by HLE Session handlers.
  * This can be provided to a ServerSession in order to hook into several relevant events
@@ -59,14 +67,28 @@ protected:
  * Class containing information about an in-flight IPC request being handled by an HLE service
  * implementation. Services should avoid using old global APIs (e.g. Kernel::GetCommandBuffer()) and
  * when possible use the APIs in this class to service the request.
+ *
+ * HLE handle protocol
+ * ===================
+ *
+ * To avoid needing HLE services to keep a separate handle table, or having to directly modify the
+ * requester's table, a tweaked protocol is used to receive and send handles in requests. The kernel
+ * will decode the incoming handles into object pointers and insert a id in the buffer where the
+ * handle would normally be. The service then calls GetIncomingHandle() with that id to get the
+ * pointer to the object. Similarly, instead of inserting a handle into the command buffer, the
+ * service calls AddOutgoingHandle() and stores the returned id where the handle would normally go.
+ *
+ * The end result is similar to just giving services their own real handle tables, but since these
+ * ids are local to a specific context, it avoids requiring services to manage handles for objects
+ * across multiple calls and ensuring that unneeded handles are cleaned up.
  */
 class HLERequestContext {
 public:
     ~HLERequestContext();
 
     /// Returns a pointer to the IPC command buffer for this request.
-    u32* CommandBuffer() const {
-        return cmd_buf;
+    u32* CommandBuffer() {
+        return cmd_buf.data();
     }
 
     /**
@@ -77,11 +99,37 @@ public:
         return session;
     }
 
+    /**
+     * Resolves a object id from the request command buffer into a pointer to an object. See the
+     * "HLE handle protocol" section in the class documentation for more details.
+     */
+    SharedPtr<Object> GetIncomingHandle(u32 id_from_cmdbuf) const;
+
+    /**
+     * Adds an outgoing object to the response, returning the id which should be used to reference
+     * it. See the "HLE handle protocol" section in the class documentation for more details.
+     */
+    u32 AddOutgoingHandle(SharedPtr<Object> object);
+
+    /**
+     * Discards all Objects from the context, invalidating all ids. This may be called after reading
+     * out all incoming objects, so that the buffer memory can be re-used for outgoing handles, but
+     * this is not required.
+     */
+    void ClearIncomingObjects();
+
 private:
     friend class Service::ServiceFrameworkBase;
 
-    u32* cmd_buf = nullptr;
+    ResultCode PopulateFromIncomingCommandBuffer(const u32_le* src_cmdbuf, Process& src_process,
+                                                 HandleTable& src_table);
+    ResultCode WriteToOutgoingCommandBuffer(u32_le* dst_cmdbuf, Process& dst_process,
+                                            HandleTable& dst_table) const;
+
+    std::array<u32, IPC::COMMAND_BUFFER_LENGTH> cmd_buf;
     SharedPtr<ServerSession> session;
+    // TODO(yuriks): Check common usage of this and optimize size accordingly
+    boost::container::small_vector<SharedPtr<Object>, 8> request_handles;
 };
 
 } // namespace Kernel

src/core/hle/service/service.cpp

@@ -2,10 +2,14 @@
 // Licensed under GPLv2 or any later version
 // Refer to the license.txt file included.
 
+#include <algorithm>
 #include <fmt/format.h>
+#include "common/assert.h"
 #include "common/logging/log.h"
 #include "common/string_util.h"
+#include "core/hle/ipc.h"
 #include "core/hle/kernel/client_port.h"
+#include "core/hle/kernel/process.h"
 #include "core/hle/kernel/server_port.h"
 #include "core/hle/kernel/server_session.h"
 #include "core/hle/service/ac/ac.h"
@@ -160,12 +164,6 @@ void ServiceFrameworkBase::ReportUnimplementedFunction(u32* cmd_buf, const Funct
 void ServiceFrameworkBase::HandleSyncRequest(SharedPtr<ServerSession> server_session) {
     u32* cmd_buf = Kernel::GetCommandBuffer();
 
-    // TODO(yuriks): The kernel should be the one handling this as part of translation after
-    // everything else is migrated
-    Kernel::HLERequestContext context;
-    context.cmd_buf = cmd_buf;
-    context.session = std::move(server_session);
-
     u32 header_code = cmd_buf[0];
     auto itr = handlers.find(header_code);
     const FunctionInfoBase* info = itr == handlers.end() ? nullptr : &itr->second;
@@ -173,9 +171,18 @@ void ServiceFrameworkBase::HandleSyncRequest(SharedPtr<ServerSession> server_ses
         return ReportUnimplementedFunction(cmd_buf, info);
     }
 
+    // TODO(yuriks): The kernel should be the one handling this as part of translation after
+    // everything else is migrated
+    Kernel::HLERequestContext context;
+    context.session = std::move(server_session);
+    context.PopulateFromIncomingCommandBuffer(cmd_buf, *Kernel::g_current_process,
+                                              Kernel::g_handle_table);
+
     LOG_TRACE(Service, "%s",
               MakeFunctionString(info->name, GetServiceName().c_str(), cmd_buf).c_str());
     handler_invoker(this, info->handler_callback, context);
+    context.WriteToOutgoingCommandBuffer(cmd_buf, *Kernel::g_current_process,
+                                         Kernel::g_handle_table);
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////

src/core/hle/service/sm/srv.cpp

@@ -7,9 +7,11 @@
 #include "common/common_types.h"
 #include "common/logging/log.h"
 #include "core/hle/ipc.h"
+#include "core/hle/ipc_helpers.h"
 #include "core/hle/kernel/client_port.h"
 #include "core/hle/kernel/client_session.h"
-#include "core/hle/kernel/handle_table.h"
+#include "core/hle/kernel/errors.h"
+#include "core/hle/kernel/hle_ipc.h"
 #include "core/hle/kernel/semaphore.h"
 #include "core/hle/kernel/server_session.h"
 #include "core/hle/service/sm/sm.h"
@@ -30,15 +32,18 @@ constexpr int MAX_PENDING_NOTIFICATIONS = 16;
  *      1: ResultCode
  */
 void SRV::RegisterClient(Kernel::HLERequestContext& ctx) {
-    u32* cmd_buff = ctx.CommandBuffer();
+    IPC::RequestParser rp(ctx, 0x1, 0, 2);
 
-    if (cmd_buff[1] != IPC::CallingPidDesc()) {
-        cmd_buff[0] = IPC::MakeHeader(0x0, 0x1, 0); // 0x40
-        cmd_buff[1] = IPC::ERR_INVALID_BUFFER_DESCRIPTOR.raw;
+    u32 pid_descriptor = rp.Pop<u32>();
+    if (pid_descriptor != IPC::CallingPidDesc()) {
+        IPC::RequestBuilder rb = rp.MakeBuilder(1, 0);
+        rb.Push(IPC::ERR_INVALID_BUFFER_DESCRIPTOR);
         return;
     }
-    cmd_buff[0] = IPC::MakeHeader(0x1, 0x1, 0); // 0x10040
-    cmd_buff[1] = RESULT_SUCCESS.raw;           // No error
+    u32 caller_pid = rp.Pop<u32>();
+
+    IPC::RequestBuilder rb = rp.MakeBuilder(1, 0);
+    rb.Push(RESULT_SUCCESS);
     LOG_WARNING(Service_SRV, "(STUBBED) called");
 }
 
@@ -53,15 +58,14 @@ void SRV::RegisterClient(Kernel::HLERequestContext& ctx) {
  *      3: Handle to semaphore signaled on process notification
  */
 void SRV::EnableNotification(Kernel::HLERequestContext& ctx) {
-    u32* cmd_buff = ctx.CommandBuffer();
+    IPC::RequestParser rp(ctx, 0x2, 0, 0);
 
     notification_semaphore =
         Kernel::Semaphore::Create(0, MAX_PENDING_NOTIFICATIONS, "SRV:Notification").Unwrap();
 
-    cmd_buff[0] = IPC::MakeHeader(0x2, 0x1, 0x2); // 0x20042
-    cmd_buff[1] = RESULT_SUCCESS.raw;             // No error
-    cmd_buff[2] = IPC::CopyHandleDesc(1);
-    cmd_buff[3] = Kernel::g_handle_table.Create(notification_semaphore).MoveFrom();
+    IPC::RequestBuilder rb = rp.MakeBuilder(1, 2);
+    rb.Push(RESULT_SUCCESS);
+    rb.PushObjects(notification_semaphore);
     LOG_WARNING(Service_SRV, "(STUBBED) called");
 }
 
@@ -77,43 +81,49 @@ void SRV::EnableNotification(Kernel::HLERequestContext& ctx) {
  *      3: Service handle
  */
 void SRV::GetServiceHandle(Kernel::HLERequestContext& ctx) {
-    ResultCode res = RESULT_SUCCESS;
-    u32* cmd_buff = ctx.CommandBuffer();
+    IPC::RequestParser rp(ctx, 0x5, 4, 0);
+    auto name_buf = rp.PopRaw<std::array<char, 8>>();
+    size_t name_len = rp.Pop<u32>();
+    u32 flags = rp.Pop<u32>();
+
+    bool return_port_on_failure = (flags & 1) == 0;
 
-    size_t name_len = cmd_buff[3];
     if (name_len > Service::kMaxPortSize) {
-        cmd_buff[1] = ERR_INVALID_NAME_SIZE.raw;
-        LOG_ERROR(Service_SRV, "called name_len=0x%X, failed with code=0x%08X", name_len,
-                  cmd_buff[1]);
+        IPC::RequestBuilder rb = rp.MakeBuilder(1, 0);
+        rb.Push(ERR_INVALID_NAME_SIZE);
+        LOG_ERROR(Service_SRV, "called name_len=0x%X -> ERR_INVALID_NAME_SIZE", name_len);
         return;
     }
-    std::string name(reinterpret_cast<const char*>(&cmd_buff[1]), name_len);
-    bool return_port_on_failure = (cmd_buff[4] & 1) == 0;
+    std::string name(name_buf.data(), name_len);
 
     // TODO(yuriks): Permission checks go here
 
     auto client_port = service_manager->GetServicePort(name);
     if (client_port.Failed()) {
-        cmd_buff[1] = client_port.Code().raw;
-        LOG_ERROR(Service_SRV, "called service=%s, failed with code=0x%08X", name.c_str(),
-                  cmd_buff[1]);
+        IPC::RequestBuilder rb = rp.MakeBuilder(1, 0);
+        rb.Push(client_port.Code());
+        LOG_ERROR(Service_SRV, "called service=%s -> error 0x%08X", name.c_str(),
+                  client_port.Code().raw);
         return;
     }
 
     auto session = client_port.Unwrap()->Connect();
-    cmd_buff[1] = session.Code().raw;
     if (session.Succeeded()) {
-        cmd_buff[3] = Kernel::g_handle_table.Create(session.MoveFrom()).MoveFrom();
-        LOG_DEBUG(Service_SRV, "called service=%s, session handle=0x%08X", name.c_str(),
-                  cmd_buff[3]);
+        LOG_DEBUG(Service_SRV, "called service=%s -> session=%u", name.c_str(),
+                  (*session)->GetObjectId());
+        IPC::RequestBuilder rb = rp.MakeBuilder(1, 2);
+        rb.Push(session.Code());
+        rb.PushObjects(session.MoveFrom());
     } else if (session.Code() == Kernel::ERR_MAX_CONNECTIONS_REACHED && return_port_on_failure) {
-        cmd_buff[1] = ERR_MAX_CONNECTIONS_REACHED.raw;
-        cmd_buff[3] = Kernel::g_handle_table.Create(client_port.MoveFrom()).MoveFrom();
-        LOG_WARNING(Service_SRV, "called service=%s, *port* handle=0x%08X", name.c_str(),
-                    cmd_buff[3]);
+        LOG_WARNING(Service_SRV, "called service=%s -> ERR_MAX_CONNECTIONS_REACHED, *port*=%u",
+                    name.c_str(), (*client_port)->GetObjectId());
+        IPC::RequestBuilder rb = rp.MakeBuilder(1, 2);
+        rb.Push(ERR_MAX_CONNECTIONS_REACHED);
+        rb.PushObjects(client_port.MoveFrom());
     } else {
-        LOG_ERROR(Service_SRV, "called service=%s, failed with code=0x%08X", name.c_str(),
-                  cmd_buff[1]);
+        LOG_ERROR(Service_SRV, "called service=%s -> error 0x%08X", name.c_str(), session.Code());
+        IPC::RequestBuilder rb = rp.MakeBuilder(1, 0);
+        rb.Push(session.Code());
     }
 }
 
@@ -127,12 +137,11 @@ void SRV::GetServiceHandle(Kernel::HLERequestContext& ctx) {
  *      1: ResultCode
  */
 void SRV::Subscribe(Kernel::HLERequestContext& ctx) {
-    u32* cmd_buff = ctx.CommandBuffer();
-
-    u32 notification_id = cmd_buff[1];
+    IPC::RequestParser rp(ctx, 0x9, 1, 0);
+    u32 notification_id = rp.Pop<u32>();
 
-    cmd_buff[0] = IPC::MakeHeader(0x9, 0x1, 0); // 0x90040
-    cmd_buff[1] = RESULT_SUCCESS.raw;           // No error
+    IPC::RequestBuilder rb = rp.MakeBuilder(1, 0);
+    rb.Push(RESULT_SUCCESS);
     LOG_WARNING(Service_SRV, "(STUBBED) called, notification_id=0x%X", notification_id);
 }
 
@@ -146,12 +155,11 @@ void SRV::Subscribe(Kernel::HLERequestContext& ctx) {
  *      1: ResultCode
  */
 void SRV::Unsubscribe(Kernel::HLERequestContext& ctx) {
-    u32* cmd_buff = ctx.CommandBuffer();
+    IPC::RequestParser rp(ctx, 0xA, 1, 0);
+    u32 notification_id = rp.Pop<u32>();
 
-    u32 notification_id = cmd_buff[1];
-
-    cmd_buff[0] = IPC::MakeHeader(0xA, 0x1, 0); // 0xA0040
-    cmd_buff[1] = RESULT_SUCCESS.raw;           // No error
+    IPC::RequestBuilder rb = rp.MakeBuilder(1, 0);
+    rb.Push(RESULT_SUCCESS);
     LOG_WARNING(Service_SRV, "(STUBBED) called, notification_id=0x%X", notification_id);
 }
 
@@ -166,13 +174,12 @@ void SRV::Unsubscribe(Kernel::HLERequestContext& ctx) {
  *      1: ResultCode
  */
 void SRV::PublishToSubscriber(Kernel::HLERequestContext& ctx) {
-    u32* cmd_buff = ctx.CommandBuffer();
-
-    u32 notification_id = cmd_buff[1];
-    u8 flags = cmd_buff[2] & 0xFF;
+    IPC::RequestParser rp(ctx, 0xC, 2, 0);
+    u32 notification_id = rp.Pop<u32>();
+    u8 flags = rp.Pop<u8>();
 
-    cmd_buff[0] = IPC::MakeHeader(0xC, 0x1, 0); // 0xC0040
-    cmd_buff[1] = RESULT_SUCCESS.raw;           // No error
+    IPC::RequestBuilder rb = rp.MakeBuilder(1, 0);
+    rb.Push(RESULT_SUCCESS);
     LOG_WARNING(Service_SRV, "(STUBBED) called, notification_id=0x%X, flags=%u", notification_id,
                 flags);
 }