dmnt: enable experimental standalone usage of gdbstub, while starlink is in dev

Makefile

@@ -112,6 +112,7 @@ dist-no-debug: all
 	mkdir -p atmosphere-$(AMSVER)/stratosphere_romfs/atmosphere/contents/0100000000000042
 	mkdir -p atmosphere-$(AMSVER)/stratosphere_romfs/atmosphere/contents/0100000000000420
 	mkdir -p atmosphere-$(AMSVER)/stratosphere_romfs/atmosphere/contents/010000000000B240
+	mkdir -p atmosphere-$(AMSVER)/stratosphere_romfs/atmosphere/contents/010000000000D609
 	mkdir -p atmosphere-$(AMSVER)/stratosphere_romfs/atmosphere/contents/010000000000D623
 	cp stratosphere/boot2/boot2.nsp atmosphere-$(AMSVER)/stratosphere_romfs/atmosphere/contents/0100000000000008/exefs.nsp
 	cp stratosphere/dmnt/dmnt.nsp atmosphere-$(AMSVER)/stratosphere_romfs/atmosphere/contents/010000000000000D/exefs.nsp
@@ -125,6 +126,7 @@ dist-no-debug: all
 	cp stratosphere/pgl/pgl.nsp atmosphere-$(AMSVER)/stratosphere_romfs/atmosphere/contents/0100000000000042/exefs.nsp
 	cp stratosphere/LogManager/LogManager.nsp atmosphere-$(AMSVER)/stratosphere_romfs/atmosphere/contents/0100000000000420/exefs.nsp
 	cp stratosphere/htc/htc.nsp atmosphere-$(AMSVER)/stratosphere_romfs/atmosphere/contents/010000000000B240/exefs.nsp
+	cp stratosphere/dmnt.gen2/dmnt.gen2.nsp atmosphere-$(AMSVER)/stratosphere_romfs/atmosphere/contents/010000000000D609/exefs.nsp
 	cp stratosphere/TioServer/TioServer.nsp atmosphere-$(AMSVER)/stratosphere_romfs/atmosphere/contents/010000000000D623/exefs.nsp
 	@build_romfs atmosphere-$(AMSVER)/stratosphere_romfs atmosphere-$(AMSVER)/atmosphere/stratosphere.romfs
 	rm -r atmosphere-$(AMSVER)/stratosphere_romfs

libraries/libstratosphere/include/stratosphere/fssystem/fssystem_utility.hpp

@@ -118,12 +118,12 @@ namespace ams::fssystem {
 
     /* Copy API. */
     Result CopyFile(fs::fsa::IFileSystem *dst_fs, fs::fsa::IFileSystem *src_fs, const char *dst_parent_path, const char *src_path, const fs::DirectoryEntry *dir_ent, void *work_buf, size_t work_buf_size);
-    NX_INLINE Result CopyFile(fs::fsa::IFileSystem *fs, const char *dst_parent_path, const char *src_path, const fs::DirectoryEntry *dir_ent, void *work_buf, size_t work_buf_size) {
+    ALWAYS_INLINE Result CopyFile(fs::fsa::IFileSystem *fs, const char *dst_parent_path, const char *src_path, const fs::DirectoryEntry *dir_ent, void *work_buf, size_t work_buf_size) {
         return CopyFile(fs, fs, dst_parent_path, src_path, dir_ent, work_buf, work_buf_size);
     }
 
     Result CopyDirectoryRecursively(fs::fsa::IFileSystem *dst_fs, fs::fsa::IFileSystem *src_fs, const char *dst_path, const char *src_path, void *work_buf, size_t work_buf_size);
-    NX_INLINE Result CopyDirectoryRecursively(fs::fsa::IFileSystem *fs, const char *dst_path, const char *src_path, void *work_buf, size_t work_buf_size) {
+    ALWAYS_INLINE Result CopyDirectoryRecursively(fs::fsa::IFileSystem *fs, const char *dst_path, const char *src_path, void *work_buf, size_t work_buf_size) {
         return CopyDirectoryRecursively(fs, fs, dst_path, src_path, work_buf, work_buf_size);
     }
 
@@ -148,11 +148,11 @@ namespace ams::fssystem {
     Result EnsureDirectoryRecursively(fs::fsa::IFileSystem *fs, const char *path);
     Result EnsureParentDirectoryRecursively(fs::fsa::IFileSystem *fs, const char *path);
 
-    template<typename F>
+    template<s64 RetryMilliSeconds = 100>
-    NX_INLINE Result RetryFinitelyForTargetLocked(F f) {
+    ALWAYS_INLINE Result RetryFinitelyForTargetLocked(auto f) {
         /* Retry up to 10 times, 100ms between retries. */
         constexpr s32 MaxRetryCount = 10;
-        constexpr TimeSpan RetryWaitTime = TimeSpan::FromMilliSeconds(100);
+        constexpr TimeSpan RetryWaitTime = TimeSpan::FromMilliSeconds(RetryMilliSeconds);
 
         s32 remaining_retries = MaxRetryCount;
         while (true) {

libraries/libstratosphere/include/stratosphere/socket/socket_api.hpp

@@ -43,6 +43,7 @@ namespace ams::socket {
 
     s32 Shutdown(s32 desc, ShutdownMethod how);
 
+    s32 Socket(Family domain, Type type, Protocol protocol);
     s32 SocketExempt(Family domain, Type type, Protocol protocol);
 
     s32 Accept(s32 desc, SockAddr *out_address, SockLenT *out_addr_len);

libraries/libstratosphere/include/stratosphere/socket/socket_system_config.hpp

@@ -57,4 +57,42 @@ namespace ams::socket {
             }
     };
 
+    class SystemConfigLightDefault : public Config {
+        public:
+            static constexpr size_t DefaultTcpInitialSendBufferSize     = 16_KB;
+            static constexpr size_t DefaultTcpInitialReceiveBufferSize  = 16_KB;
+            static constexpr size_t DefaultTcpAutoSendBufferSizeMax     = 0_KB;
+            static constexpr size_t DefaultTcpAutoReceiveBufferSizeMax  = 0_KB;
+            static constexpr size_t DefaultUdpSendBufferSize            = 9_KB;
+            static constexpr size_t DefaultUdpReceiveBufferSize         = 42240;
+            static constexpr auto   DefaultSocketBufferEfficiency       = 2;
+            static constexpr auto   DefaultConcurrency                  = 2;
+            static constexpr size_t DefaultAllocatorPoolSize            = 64_KB;
+
+            static constexpr size_t PerTcpSocketWorstCaseMemoryPoolSize = [] {
+                constexpr size_t WorstCaseTcpSendBufferSize    = AlignMss(std::max(DefaultTcpInitialSendBufferSize, DefaultTcpAutoSendBufferSizeMax));
+                constexpr size_t WorstCaseTcpReceiveBufferSize = AlignMss(std::max(DefaultTcpInitialReceiveBufferSize, DefaultTcpAutoReceiveBufferSizeMax));
+
+                return util::AlignUp(WorstCaseTcpSendBufferSize * DefaultSocketBufferEfficiency + WorstCaseTcpReceiveBufferSize * DefaultSocketBufferEfficiency, os::MemoryPageSize);
+            }();
+
+            static constexpr size_t PerUdpSocketWorstCaseMemoryPoolSize = [] {
+                constexpr size_t WorstCaseUdpSendBufferSize    = AlignMss(DefaultUdpSendBufferSize);
+                constexpr size_t WorstCaseUdpReceiveBufferSize = AlignMss(DefaultUdpReceiveBufferSize);
+
+                return util::AlignUp(WorstCaseUdpSendBufferSize * DefaultSocketBufferEfficiency + WorstCaseUdpReceiveBufferSize * DefaultSocketBufferEfficiency, os::MemoryPageSize);
+            }();
+        public:
+            constexpr SystemConfigLightDefault(void *mp, size_t mp_sz, size_t ap, int c=DefaultConcurrency)
+                : Config(mp, mp_sz, ap,
+                         DefaultTcpInitialSendBufferSize, DefaultTcpInitialReceiveBufferSize,
+                         DefaultTcpAutoSendBufferSizeMax, DefaultTcpAutoReceiveBufferSizeMax,
+                         DefaultUdpSendBufferSize, DefaultUdpReceiveBufferSize,
+                         DefaultSocketBufferEfficiency, c)
+            {
+                /* Mark as system. */
+                m_system = true;
+            }
+    };
+
 }

libraries/libstratosphere/source/boot2/boot2_api.cpp

@@ -188,6 +188,12 @@ namespace ams::boot2 {
             return enable_htc != 0;
         }
 
+        bool IsStandaloneGdbstubEnabled() {
+            u8 enable_gdbstub = 0;
+            settings::fwdbg::GetSettingsItemValue(std::addressof(enable_gdbstub), sizeof(enable_gdbstub), "atmosphere", "enable_standalone_gdbstub");
+            return enable_gdbstub != 0;
+        }
+
         bool IsAtmosphereLogManagerEnabled() {
             /* If htc is enabled, ams log manager is enabled. */
             if (IsHtcEnabled()) {
@@ -403,6 +409,9 @@ namespace ams::boot2 {
             LaunchProgram(nullptr, ncm::ProgramLocation::Make(ncm::SystemProgramId::Htc,      ncm::StorageId::None), 0);
             LaunchProgram(nullptr, ncm::ProgramLocation::Make(ncm::SystemProgramId::Cs,       ncm::StorageId::None), 0);
             LaunchProgram(nullptr, ncm::ProgramLocation::Make(ncm::SystemProgramId::DmntGen2, ncm::StorageId::None), 0);
+        } else if (IsStandaloneGdbstubEnabled()) {
+            LaunchProgram(nullptr, ncm::ProgramLocation::Make(ncm::SystemProgramId::DmntGen2, ncm::StorageId::None), 0);
+            LaunchProgram(nullptr, ncm::ProgramLocation::Make(ncm::SystemProgramId::Tma,  ncm::StorageId::BuiltInSystem), 0);
         } else {
             LaunchProgram(nullptr, ncm::ProgramLocation::Make(ncm::SystemProgramId::Dmnt, ncm::StorageId::None), 0);
             LaunchProgram(nullptr, ncm::ProgramLocation::Make(ncm::SystemProgramId::Tma,  ncm::StorageId::BuiltInSystem), 0);

libraries/libstratosphere/source/socket/impl/socket_api.hpp

@@ -41,6 +41,7 @@ namespace ams::socket::impl {
 
     s32 Shutdown(s32 desc, ShutdownMethod how);
 
+    s32 Socket(Family domain, Type type, Protocol protocol);
     s32 SocketExempt(Family domain, Type type, Protocol protocol);
 
     s32 Accept(s32 desc, SockAddr *out_address, SockLenT *out_addr_len);

libraries/libstratosphere/source/socket/impl/socket_api.os.horizon.cpp

@@ -206,6 +206,8 @@ namespace ams::socket::impl {
 
             /* TODO: socket::resolver::EnableResolverCalls()? Not necessary in our case (htc), but consider calling it. */
 
+            g_initialized = true;
+
             return ResultSuccess();
         }
 
@@ -422,6 +424,22 @@ namespace ams::socket::impl {
         return result;
     }
 
+    s32 Socket(Family domain, Type type, Protocol protocol) {
+        /* Check pre-conditions. */
+        AMS_ABORT_UNLESS(IsInitialized());
+
+        /* Perform the call. */
+        Errno error = Errno::ESuccess;
+        int result  = ::bsdSocket(static_cast<int>(domain), static_cast<int>(type), static_cast<int>(protocol));
+        TranslateResultToBsdError(error, result);
+
+        if (result < 0) {
+            socket::impl::SetLastError(error);
+        }
+
+        return result;
+    }
+
     s32 SocketExempt(Family domain, Type type, Protocol protocol) {
         /* Check pre-conditions. */
         AMS_ABORT_UNLESS(IsInitialized());

libraries/libstratosphere/source/socket/socket_api.cpp

@@ -74,6 +74,10 @@ namespace ams::socket {
         return impl::Shutdown(desc, how);
     }
 
+    s32 Socket(Family domain, Type type, Protocol protocol) {
+        return impl::Socket(domain, type, protocol);
+    }
+
     s32 SocketExempt(Family domain, Type type, Protocol protocol) {
         return impl::SocketExempt(domain, type, protocol);
     }

stratosphere/ams_mitm/source/set_mitm/settings_sd_kvs.cpp

@@ -378,6 +378,12 @@ namespace ams::settings::fwdbg {
             /* 0 = Disabled, 1 = Enabled */
             R_ABORT_UNLESS(ParseSettingsItemValue("atmosphere", "enable_htc", "u8!0x0"));
 
+            /* Controls whether atmosphere's dmnt.gen2 gdbstub should run as a standalone via sockets. */
+            /* Note that this setting is ignored (and treated as 0) when htc is enabled. */
+            /* Note that this setting may disappear in the future. */
+            /* 0 = Disabled, 1 = Enabled */
+            R_ABORT_UNLESS(ParseSettingsItemValue("atmosphere", "enable_standalone_gdbstub", "u8!0x0"));
+
             /* Controls whether atmosphere's log manager is enabled. */
             /* Note that this setting is ignored (and treated as 1) when htc is enabled. */
             /* 0 = Disabled, 1 = Enabled */

stratosphere/dmnt.gen2/dmnt.gen2.json

@@ -15,7 +15,7 @@
 	"filesystem_access":	{
 		"permissions":	"0xFFFFFFFFFFFFFFFF"
 	},
-	"service_access":	["pm:dmnt", "ldr:dmnt", "ro:dmnt", "ns:dev", "lr", "fsp-srv", "fatal:u", "pgl", "htcs"],
+	"service_access":	["pm:dmnt", "ldr:dmnt", "ro:dmnt", "ns:dev", "lr", "fsp-srv", "fatal:u", "pgl", "htcs", "bsd:s"],
 	"service_host":	[],
 	"kernel_capabilities":	[{
 			"type":	"kernel_flags",

stratosphere/dmnt.gen2/source/dmnt2_debug_log.cpp

@@ -16,7 +16,8 @@
 #include <stratosphere.hpp>
 #include "dmnt2_debug_log.hpp"
 
-#define AMS_DMNT2_ENABLE_HTCS_DEBUG_LOG
+// TODO: This should be converted to use log manager. */
+//#define AMS_DMNT2_ENABLE_HTCS_DEBUG_LOG
 
 #if defined(AMS_DMNT2_ENABLE_HTCS_DEBUG_LOG)
 
@@ -164,15 +165,78 @@ namespace ams::dmnt {
 
 namespace ams::dmnt {
 
+    //#define AMS_DMNT2_ENABLE_SD_CARD_DEBUG_LOG
+
+    #if defined(AMS_DMNT2_ENABLE_SD_CARD_DEBUG_LOG)
+
+    namespace {
+
+        alignas(0x40) constinit u8 g_buffer[os::MemoryPageSize * 4];
+        constinit lmem::HeapHandle g_debug_log_heap;
+        constinit fs::FileHandle g_debug_log_file;
+
+        constinit os::SdkMutex g_fs_mutex;
+        constinit s64 g_fs_offset = 0;
+
+        void *Allocate(size_t size) {
+            return lmem::AllocateFromExpHeap(g_debug_log_heap, size);
+        }
+
+        void Deallocate(void *p, size_t size) {
+            AMS_UNUSED(size);
+            return lmem::FreeToExpHeap(g_debug_log_heap, p);
+        }
+
+    }
 
     void InitializeDebugLog() {
-        /* Do nothing. */
+        g_debug_log_heap = lmem::CreateExpHeap(g_buffer, sizeof(g_buffer), lmem::CreateOption_ThreadSafe);
+
+        fs::SetAllocator(Allocate, Deallocate);
+        fs::InitializeForSystem();
+        fs::SetEnabledAutoAbort(false);
+
+        R_ABORT_UNLESS(fs::MountSdCard("sdmc"));
+
+        fs::DeleteFile("sdmc:/dmnt2.log");
+        R_ABORT_UNLESS(fs::CreateFile("sdmc:/dmnt2.log", 0));
+        R_ABORT_UNLESS(fs::OpenFile(std::addressof(g_debug_log_file), "sdmc:/dmnt2.log", fs::OpenMode_Write | fs::OpenMode_AllowAppend));
     }
 
     void DebugLog(const char *prefix, const char *fmt, ...) {
         /* Do nothing. */
+        char buffer[0x200];
+        {
+            const auto prefix_len = std::strlen(prefix);
+            std::memcpy(buffer, prefix, prefix_len);
+
+            std::va_list vl;
+            va_start(vl, fmt);
+            util::VSNPrintf(buffer + prefix_len, sizeof(buffer) - prefix_len, fmt, vl);
+            va_end(vl);
         }
 
+        const auto len = std::strlen(buffer);
+
+        std::scoped_lock lk(g_fs_mutex);
+        R_ABORT_UNLESS(fs::WriteFile(g_debug_log_file, g_fs_offset, buffer, len, fs::WriteOption::Flush));
+        g_fs_offset += len;
+    }
+
+    #else
+
+    void InitializeDebugLog() {
+        /* ... */
+    }
+
+    void DebugLog(const char *prefix, const char *fmt, ...) {
+        AMS_UNUSED(prefix, fmt);
+    }
+
+    #endif
+
+
+
 }
 
 

stratosphere/dmnt.gen2/source/dmnt2_gdb_packet_io.cpp

@@ -41,7 +41,7 @@ namespace ams::dmnt {
 
     }
 
-    void GdbPacketIo::SendPacket(bool *out_break, const char *src, HtcsSession *session) {
+    void GdbPacketIo::SendPacket(bool *out_break, const char *src, TransportSession *session) {
         /* Default to not breaked. */
         *out_break = false;
 
@@ -99,7 +99,7 @@ namespace ams::dmnt {
         }
     }
 
-    char *GdbPacketIo::ReceivePacket(bool *out_break, char *dst, size_t size, HtcsSession *session) {
+    char *GdbPacketIo::ReceivePacket(bool *out_break, char *dst, size_t size, TransportSession *session) {
         /* Default to not breaked. */
         *out_break = false;
 

stratosphere/dmnt.gen2/source/dmnt2_gdb_packet_io.hpp

@@ -15,7 +15,7 @@
  */
 #pragma once
 #include <stratosphere.hpp>
-#include "dmnt2_htcs_session.hpp"
+#include "dmnt2_transport_session.hpp"
 
 namespace ams::dmnt {
 
@@ -30,8 +30,8 @@ namespace ams::dmnt {
 
             void SetNoAck() { m_no_ack = true; }
 
-            void SendPacket(bool *out_break, const char *src, HtcsSession *session);
+            void SendPacket(bool *out_break, const char *src, TransportSession *session);
-            char *ReceivePacket(bool *out_break, char *dst, size_t size, HtcsSession *session);
+            char *ReceivePacket(bool *out_break, char *dst, size_t size, TransportSession *session);
     };
 
 }

stratosphere/dmnt.gen2/source/dmnt2_gdb_server.cpp

@@ -15,6 +15,7 @@
  */
 #include <stratosphere.hpp>
 #include "dmnt2_debug_log.hpp"
+#include "dmnt2_transport_layer.hpp"
 #include "dmnt2_gdb_server.hpp"
 #include "dmnt2_gdb_server_impl.hpp"
 
@@ -36,34 +37,28 @@ namespace ams::dmnt {
             while (true) {
                 /* Get a socket. */
                 int fd;
-                while ((fd = htcs::Socket()) == -1) {
+                while ((fd = transport::Socket()) == -1) {
                     os::SleepThread(TimeSpan::FromSeconds(1));
                 }
 
                 /* Ensure we cleanup the socket when we're done with it. */
                 ON_SCOPE_EXIT {
-                    htcs::Close(fd);
+                    transport::Close(fd);
                     os::SleepThread(TimeSpan::FromSeconds(1));
                 };
 
-                /* Create a sock addr for our server. */
-                htcs::SockAddrHtcs addr;
-                addr.family    = htcs::HTCS_AF_HTCS;
-                addr.peer_name = htcs::GetPeerNameAny();
-                std::strcpy(addr.port_name.name, "iywys@$gdb");
-
                 /* Bind. */
-                if (htcs::Bind(fd, std::addressof(addr)) == -1) {
+                if (transport::Bind(fd, transport::PortName_GdbServer) == -1) {
                     continue;
                 }
 
                 /* Listen on our port. */
-                while (htcs::Listen(fd, 0) == 0) {
+                while (transport::Listen(fd, 0) == 0) {
                     /* Continue accepting clients, so long as we can. */
                     int client_fd;
                     while (true) {
                         /* Try to accept a client. */
-                        if (client_fd = htcs::Accept(fd, std::addressof(addr)); client_fd < 0) {
+                        if (client_fd = transport::Accept(fd); client_fd < 0) {
                             break;
                         }
 
@@ -77,7 +72,7 @@ namespace ams::dmnt {
                         }
 
                         /* Close the client socket. */
-                        htcs::Close(client_fd);
+                        transport::Close(client_fd);
                     }
                 }
             }

stratosphere/dmnt.gen2/source/dmnt2_gdb_server_impl.hpp

@@ -31,7 +31,7 @@ namespace ams::dmnt {
             };
         private:
             int m_socket;
-            HtcsSession m_session;
+            TransportSession m_session;
             GdbPacketIo m_packet_io;
             char *m_receive_packet{nullptr};
             char *m_reply_packet{nullptr};

stratosphere/dmnt.gen2/source/dmnt2_main.cpp

@@ -16,15 +16,22 @@
 #include <stratosphere.hpp>
 #include "dmnt2_debug_log.hpp"
 #include "dmnt2_gdb_server.hpp"
+#include "dmnt2_transport_layer.hpp"
 
 namespace ams {
 
-    namespace dmnt {
-
     namespace {
 
-            alignas(0x40) constinit u8 g_htcs_buffer[4_KB];
+        bool IsHtcEnabled() {
+            u8 enable_htc = 0;
+            settings::fwdbg::GetSettingsItemValue(std::addressof(enable_htc), sizeof(enable_htc), "atmosphere", "enable_htc");
+            return enable_htc != 0;
+        }
 
+        bool IsStandaloneGdbstubEnabled() {
+            u8 enable_gdbstub = 0;
+            settings::fwdbg::GetSettingsItemValue(std::addressof(enable_gdbstub), sizeof(enable_gdbstub), "atmosphere", "enable_standalone_gdbstub");
+            return enable_gdbstub != 0;
         }
 
     }
@@ -50,11 +57,23 @@ namespace ams {
         os::SetThreadNamePointer(os::GetCurrentThread(), AMS_GET_SYSTEM_THREAD_NAME(dmnt, Main));
         AMS_ASSERT(os::GetThreadPriority(os::GetCurrentThread()) == AMS_GET_SYSTEM_THREAD_PRIORITY(dmnt, Main));
 
-        /* Initialize htcs. */
+        bool use_htcs = false, use_tcp = false;
-        constexpr auto HtcsSocketCountMax = 8;
+        {
-        const size_t buffer_size = htcs::GetWorkingMemorySize(HtcsSocketCountMax);
+            R_ABORT_UNLESS(::setsysInitialize());
-        AMS_ABORT_UNLESS(sizeof(dmnt::g_htcs_buffer) >= buffer_size);
+            ON_SCOPE_EXIT { ::setsysExit(); };
-        htcs::InitializeForSystem(dmnt::g_htcs_buffer, buffer_size, HtcsSocketCountMax);
+
+            use_htcs = IsHtcEnabled();
+            use_tcp  = IsStandaloneGdbstubEnabled();
+        }
+
+        /* Initialize transport layer. */
+        if (use_htcs) {
+            dmnt::transport::InitializeByHtcs();
+        } else if (use_tcp) {
+            dmnt::transport::InitializeByTcp();
+        } else {
+            return;
+        }
 
         /* Initialize debug log thread. */
         dmnt::InitializeDebugLog();

stratosphere/dmnt.gen2/source/dmnt2_transport_layer.cpp

@@ -0,0 +1,196 @@
+/*
+ * Copyright (c) Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <stratosphere.hpp>
+#include "dmnt2_transport_layer.hpp"
+
+namespace ams::dmnt::transport {
+
+    namespace {
+
+        enum SocketMode {
+            SocketMode_Invalid,
+            SocketMode_Htcs,
+            SocketMode_Tcp,
+        };
+
+        constexpr inline const u16 ListenPort_GdbServer   = 22225;
+        constexpr inline const u16 ListenPort_GdbDebugLog = 22227;
+
+        constinit os::SdkMutex g_socket_init_mutex;
+        constinit SocketMode g_socket_mode = SocketMode_Invalid;
+
+        constexpr inline size_t RequiredAlignment = std::max(os::ThreadStackAlignment, os::MemoryPageSize);
+
+        using SocketConfigType = socket::SystemConfigLightDefault;
+
+        /* TODO: If we ever use resolvers, increase this. */
+        constexpr inline size_t SocketAllocatorSize  = 4_KB;
+        constexpr inline size_t SocketMemoryPoolSize = util::AlignUp(SocketConfigType::PerTcpSocketWorstCaseMemoryPoolSize + SocketConfigType::PerUdpSocketWorstCaseMemoryPoolSize, os::MemoryPageSize);
+
+        constexpr inline size_t SocketRequiredSize   = util::AlignUp(SocketMemoryPoolSize + SocketAllocatorSize, os::MemoryPageSize);
+
+        /* Declare the memory pool. */
+        alignas(RequiredAlignment) constinit u8 g_socket_memory[SocketRequiredSize];
+
+        constexpr inline const SocketConfigType SocketConfig(g_socket_memory, SocketRequiredSize, SocketAllocatorSize, 2);
+
+    }
+
+    void InitializeByHtcs() {
+        std::scoped_lock lk(g_socket_init_mutex);
+        AMS_ABORT_UNLESS(g_socket_mode == SocketMode_Invalid);
+
+        constexpr auto HtcsSocketCountMax = 8;
+        const size_t buffer_size = htcs::GetWorkingMemorySize(HtcsSocketCountMax);
+        AMS_ABORT_UNLESS(sizeof(g_socket_memory) >= buffer_size);
+        htcs::InitializeForSystem(g_socket_memory, sizeof(g_socket_memory), HtcsSocketCountMax);
+
+        g_socket_mode = SocketMode_Htcs;
+    }
+
+    void InitializeByTcp() {
+        std::scoped_lock lk(g_socket_init_mutex);
+        AMS_ABORT_UNLESS(g_socket_mode == SocketMode_Invalid);
+
+        R_ABORT_UNLESS(socket::Initialize(SocketConfig));
+
+        g_socket_mode = SocketMode_Tcp;
+    }
+
+    s32 Socket() {
+        switch (g_socket_mode) {
+            case SocketMode_Htcs: return htcs::Socket();
+            case SocketMode_Tcp:  return socket::Socket(socket::Family::Af_Inet, socket::Type::Sock_Stream, socket::Protocol::IpProto_Tcp);
+            AMS_UNREACHABLE_DEFAULT_CASE();
+        }
+    }
+
+    s32 Close(s32 desc) {
+        switch (g_socket_mode) {
+            case SocketMode_Htcs:   return htcs::Close(desc);
+            case SocketMode_Tcp: return socket::Close(desc);
+            AMS_UNREACHABLE_DEFAULT_CASE();
+        }
+    }
+
+    s32 Bind(s32 desc, PortName port_name) {
+        switch (g_socket_mode) {
+            case SocketMode_Htcs:
+                {
+                    htcs::SockAddrHtcs addr;
+                    addr.family    = htcs::HTCS_AF_HTCS;
+                    addr.peer_name = htcs::GetPeerNameAny();
+                    switch (port_name) {
+                        case PortName_GdbServer:   std::strcpy(addr.port_name.name, "iywys@$gdb"); break;
+                        case PortName_GdbDebugLog: std::strcpy(addr.port_name.name, "iywys@$dmnt2_log"); break;
+                        AMS_UNREACHABLE_DEFAULT_CASE();
+                    }
+
+                    return htcs::Bind(desc, std::addressof(addr));
+                }
+                break;
+            case SocketMode_Tcp:
+                {
+                    socket::SockAddrIn addr = {};
+                    addr.sin_family      = socket::Family::Af_Inet;
+                    addr.sin_addr.s_addr = socket::InAddr_Any;
+
+                    switch (port_name){
+                        case PortName_GdbServer:   addr.sin_port = socket::InetHtons(static_cast<u16>(ListenPort_GdbServer)); break;
+                        case PortName_GdbDebugLog: addr.sin_port = socket::InetHtons(static_cast<u16>(ListenPort_GdbDebugLog)); break;
+                        AMS_UNREACHABLE_DEFAULT_CASE();
+                    }
+
+                    return socket::Bind(desc, reinterpret_cast<socket::SockAddr *>(std::addressof(addr)), sizeof(addr));
+                }
+                break;
+            AMS_UNREACHABLE_DEFAULT_CASE();
+        }
+    }
+
+    s32 Listen(s32 desc, s32 backlog_count) {
+        switch (g_socket_mode) {
+            case SocketMode_Htcs: return htcs::Listen(desc, backlog_count);
+            case SocketMode_Tcp:  return socket::Listen(desc, backlog_count);
+            AMS_UNREACHABLE_DEFAULT_CASE();
+        }
+    }
+
+    s32 Accept(s32 desc) {
+        switch (g_socket_mode) {
+            case SocketMode_Htcs:
+                {
+                    htcs::SockAddrHtcs addr;
+                    addr.family    = htcs::HTCS_AF_HTCS;
+                    addr.peer_name = htcs::GetPeerNameAny();
+                    addr.port_name.name[0] = '\x00';
+
+                    return htcs::Accept(desc, std::addressof(addr));
+                }
+                break;
+            case SocketMode_Tcp:
+                {
+                    socket::SockAddrIn addr = {};
+                    socket::SockLenT addr_len = sizeof(addr);
+
+                    return socket::Accept(desc, reinterpret_cast<socket::SockAddr *>(std::addressof(addr)), std::addressof(addr_len));
+                }
+                break;
+            AMS_UNREACHABLE_DEFAULT_CASE();
+        }
+    }
+
+    s32 Shutdown(s32 desc) {
+        switch (g_socket_mode) {
+            case SocketMode_Htcs: return htcs::Shutdown(desc, htcs::HTCS_SHUT_RDWR);
+            case SocketMode_Tcp:  return socket::Shutdown(desc, socket::ShutdownMethod::Shut_RdWr);
+            AMS_UNREACHABLE_DEFAULT_CASE();
+        }
+    }
+
+    ssize_t Recv(s32 desc, void *buffer, size_t buffer_size, s32 flags) {
+        switch (g_socket_mode) {
+            case SocketMode_Htcs: return htcs::Recv(desc, buffer, buffer_size, flags);
+            case SocketMode_Tcp:  return socket::Recv(desc, buffer, buffer_size, static_cast<socket::MsgFlag>(flags));
+            AMS_UNREACHABLE_DEFAULT_CASE();
+        }
+    }
+
+    ssize_t Send(s32 desc, const void *buffer, size_t buffer_size, s32 flags) {
+        switch (g_socket_mode) {
+            case SocketMode_Htcs: return htcs::Send(desc, buffer, buffer_size, flags);
+            case SocketMode_Tcp:  return socket::Send(desc, buffer, buffer_size, static_cast<socket::MsgFlag>(flags));
+            AMS_UNREACHABLE_DEFAULT_CASE();
+        }
+    }
+
+    s32 GetLastError() {
+        switch (g_socket_mode) {
+            case SocketMode_Htcs: return htcs::GetLastError();
+            case SocketMode_Tcp:  return static_cast<s32>(socket::GetLastError());
+            AMS_UNREACHABLE_DEFAULT_CASE();
+        }
+    }
+
+    bool IsLastErrorEAgain() {
+        switch (g_socket_mode) {
+            case SocketMode_Htcs: return htcs::GetLastError() == htcs::HTCS_EAGAIN;
+            case SocketMode_Tcp:  return socket::GetLastError() == socket::Errno::EAgain;
+            AMS_UNREACHABLE_DEFAULT_CASE();
+        }
+    }
+
+}

stratosphere/dmnt.gen2/source/dmnt2_transport_layer.hpp

@@ -0,0 +1,42 @@
+/*
+ * Copyright (c) Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#pragma once
+#include <stratosphere.hpp>
+
+namespace ams::dmnt::transport {
+
+    void InitializeByHtcs();
+    void InitializeByTcp();
+
+    enum PortName {
+        PortName_GdbServer,
+        PortName_GdbDebugLog,
+    };
+
+    s32 Socket();
+    s32 Close(s32 desc);
+    s32 Bind(s32 desc, PortName port_name);
+    s32 Listen(s32 desc, s32 backlog_count);
+    s32 Accept(s32 desc);
+    s32 Shutdown(s32 desc);
+
+    ssize_t Recv(s32 desc, void *buffer, size_t buffer_size, s32 flags);
+    ssize_t Send(s32 desc, const void *buffer, size_t buffer_size, s32 flags);
+
+    s32 GetLastError();
+    bool IsLastErrorEAgain();
+
+}

stratosphere/dmnt.gen2/source/dmnt2_transport_receive_buffer.cpp

@@ -14,11 +14,11 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 #include <stratosphere.hpp>
-#include "dmnt2_htcs_receive_buffer.hpp"
+#include "dmnt2_transport_receive_buffer.hpp"
 
 namespace ams::dmnt {
 
-    ssize_t HtcsReceiveBuffer::Read(void *dst, size_t size) {
+    ssize_t TransportReceiveBuffer::Read(void *dst, size_t size) {
         /* Acquire exclusive access to ourselves. */
         std::scoped_lock lk(m_mutex);
 
@@ -50,7 +50,7 @@ namespace ams::dmnt {
         return readable;
     }
 
-    ssize_t HtcsReceiveBuffer::Write(const void *src, size_t size) {
+    ssize_t TransportReceiveBuffer::Write(const void *src, size_t size) {
         /* Acquire exclusive access to ourselves. */
         std::scoped_lock lk(m_mutex);
 
@@ -71,7 +71,7 @@ namespace ams::dmnt {
         return size;
     }
 
-    bool HtcsReceiveBuffer::WaitToBeReadable() {
+    bool TransportReceiveBuffer::WaitToBeReadable() {
         /* Check if we're already readable. */
         {
             std::scoped_lock lk(m_mutex);
@@ -91,7 +91,7 @@ namespace ams::dmnt {
         return this->IsValid();
     }
 
-    bool HtcsReceiveBuffer::WaitToBeReadable(TimeSpan timeout) {
+    bool TransportReceiveBuffer::WaitToBeReadable(TimeSpan timeout) {
         /* Check if we're already readable. */
         {
             std::scoped_lock lk(m_mutex);
@@ -111,7 +111,7 @@ namespace ams::dmnt {
         return res && this->IsValid();
     }
 
-    bool HtcsReceiveBuffer::WaitToBeWritable() {
+    bool TransportReceiveBuffer::WaitToBeWritable() {
         /* Check if we're already writable. */
         {
             std::scoped_lock lk(m_mutex);
@@ -131,7 +131,7 @@ namespace ams::dmnt {
         return this->IsValid();
     }
 
-    void HtcsReceiveBuffer::Invalidate() {
+    void TransportReceiveBuffer::Invalidate() {
         /* Acquire exclusive access to ourselves. */
         std::scoped_lock lk(m_mutex);
 

stratosphere/dmnt.gen2/source/dmnt2_transport_receive_buffer.hpp

@@ -18,7 +18,7 @@
 
 namespace ams::dmnt {
 
-    class HtcsReceiveBuffer {
+    class TransportReceiveBuffer {
         public:
             static constexpr size_t ReceiveBufferSize = 4_KB;
         private:
@@ -30,7 +30,7 @@ namespace ams::dmnt {
             size_t m_offset;
             bool m_valid;
         public:
-            HtcsReceiveBuffer() : m_readable_event(os::EventClearMode_ManualClear), m_writable_event(os::EventClearMode_ManualClear), m_mutex(), m_readable_size(), m_offset(), m_valid(true) { /* ... */ }
+            TransportReceiveBuffer() : m_readable_event(os::EventClearMode_ManualClear), m_writable_event(os::EventClearMode_ManualClear), m_mutex(), m_readable_size(), m_offset(), m_valid(true) { /* ... */ }
 
             ALWAYS_INLINE bool IsReadable() const { return m_readable_size != 0; }
             ALWAYS_INLINE bool IsWritable() const { return m_readable_size == 0; }

stratosphere/dmnt.gen2/source/dmnt2_transport_session.cpp

@@ -14,12 +14,13 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 #include <stratosphere.hpp>
-#include "dmnt2_htcs_session.hpp"
+#include "dmnt2_transport_layer.hpp"
+#include "dmnt2_transport_session.hpp"
 #include "dmnt2_debug_log.hpp"
 
 namespace ams::dmnt {
 
-    HtcsSession::HtcsSession(int fd) : m_socket(fd), m_valid(true) {
+    TransportSession::TransportSession(int fd) : m_socket(fd), m_valid(true) {
         /* Create our thread. */
         R_ABORT_UNLESS(os::CreateThread(std::addressof(m_receive_thread), ReceiveThreadEntry, this, m_receive_thread_stack, sizeof(m_receive_thread_stack), os::HighestThreadPriority - 1));
 
@@ -30,7 +31,7 @@ namespace ams::dmnt {
         AMS_DMNT2_GDB_LOG_INFO("Created Session %d\n", m_socket);
     }
 
-    HtcsSession::~HtcsSession() {
+    TransportSession::~TransportSession() {
         /* Note that we connected. */
         AMS_DMNT2_GDB_LOG_INFO("Closing Session %d\n", m_socket);
 
@@ -38,25 +39,25 @@ namespace ams::dmnt {
         m_receive_buffer.Invalidate();
 
         /* Shutdown our socket. */
-        htcs::Shutdown(m_socket, htcs::HTCS_SHUT_RDWR);
+        transport::Shutdown(m_socket);
 
         /* Wait for our thread. */
         os::WaitThread(std::addressof(m_receive_thread));
         os::DestroyThread(std::addressof(m_receive_thread));
 
         /* Close our socket. */
-        htcs::Close(m_socket);
+        transport::Close(m_socket);
     }
 
-    bool HtcsSession::WaitToBeReadable() {
+    bool TransportSession::WaitToBeReadable() {
         return m_receive_buffer.WaitToBeReadable();
     }
 
-    bool HtcsSession::WaitToBeReadable(TimeSpan timeout) {
+    bool TransportSession::WaitToBeReadable(TimeSpan timeout) {
         return m_receive_buffer.WaitToBeReadable(timeout);
     }
 
-    util::optional<char> HtcsSession::GetChar() {
+    util::optional<char> TransportSession::GetChar() {
         /* Wait for us to have data. */
         m_receive_buffer.WaitToBeReadable();
 
@@ -69,9 +70,9 @@ namespace ams::dmnt {
         }
     }
 
-    ssize_t HtcsSession::PutChar(char c) {
+    ssize_t TransportSession::PutChar(char c) {
         /* Send the character. */
-        const auto sent = htcs::Send(m_socket, std::addressof(c), sizeof(c), 0);
+        const auto sent = transport::Send(m_socket, std::addressof(c), sizeof(c), 0);
         if (sent < 0) {
             m_valid = false;
         }
@@ -79,13 +80,13 @@ namespace ams::dmnt {
         return sent;
     }
 
-    ssize_t HtcsSession::PutString(const char *str) {
+    ssize_t TransportSession::PutString(const char *str) {
         /* Repeatedly send until all is sent. */
         const size_t len = std::strlen(str);
 
         size_t remaining = len;
         while (remaining > 0) {
-            const auto sent = htcs::Send(m_socket, str, remaining, 0);
+            const auto sent = transport::Send(m_socket, str, remaining, 0);
             if (sent >= 0) {
                 remaining -= sent;
                 str += sent;
@@ -98,22 +99,22 @@ namespace ams::dmnt {
         return len;
     }
 
-    void HtcsSession::ReceiveThreadFunction() {
+    void TransportSession::ReceiveThreadFunction() {
         /* Create temporary buffer. */
-        u8 buffer[HtcsReceiveBuffer::ReceiveBufferSize];
+        u8 buffer[TransportReceiveBuffer::ReceiveBufferSize];
 
         /* Loop receiving data. */
         while (true) {
             /* Receive data. */
-            const auto res = htcs::Recv(m_socket, buffer, sizeof(buffer), 0);
+            const auto res = transport::Recv(m_socket, buffer, sizeof(buffer), 0);
             if (res > 0) {
                 /* Write the data to our buffer. */
                 m_receive_buffer.WaitToBeWritable();
                 m_receive_buffer.Write(buffer, res);
             } else {
                 /* Otherwise, if we got an error other than "try again", we're done. */
-                if (htcs::GetLastError() != htcs::HTCS_EAGAIN) {
+                if (!transport::IsLastErrorEAgain()) {
-                    AMS_DMNT2_GDB_LOG_INFO("Session %d invalid, res=%ld, err=%d\n", m_socket, res, static_cast<int>(htcs::GetLastError()));
+                    AMS_DMNT2_GDB_LOG_INFO("Session %d invalid, res=%ld, err=%d\n", m_socket, res, static_cast<int>(transport::GetLastError()));
                     m_valid = false;
                     break;
                 }

stratosphere/dmnt.gen2/source/dmnt2_transport_session.hpp

@@ -15,20 +15,20 @@
  */
 #pragma once
 #include <stratosphere.hpp>
-#include "dmnt2_htcs_receive_buffer.hpp"
+#include "dmnt2_transport_receive_buffer.hpp"
 
 namespace ams::dmnt {
 
-    class HtcsSession {
+    class TransportSession {
         private:
-            alignas(os::ThreadStackAlignment) u8 m_receive_thread_stack[util::AlignUp(os::MemoryPageSize + HtcsReceiveBuffer::ReceiveBufferSize, os::ThreadStackAlignment)];
+            alignas(os::ThreadStackAlignment) u8 m_receive_thread_stack[util::AlignUp(os::MemoryPageSize + TransportReceiveBuffer::ReceiveBufferSize, os::ThreadStackAlignment)];
-            HtcsReceiveBuffer m_receive_buffer;
+            TransportReceiveBuffer m_receive_buffer;
             os::ThreadType m_receive_thread;
             int m_socket;
             bool m_valid;
         public:
-            HtcsSession(int fd);
+            TransportSession(int fd);
-            ~HtcsSession();
+            ~TransportSession();
 
             ALWAYS_INLINE bool IsValid() const { return m_valid; }
 
@@ -41,7 +41,7 @@ namespace ams::dmnt {
 
         private:
             static void ReceiveThreadEntry(void *arg) {
-                static_cast<HtcsSession *>(arg)->ReceiveThreadFunction();
+                static_cast<TransportSession *>(arg)->ReceiveThreadFunction();
             }
 
             void ReceiveThreadFunction();