Qt: Implement GDB server

src/duckstation-qt/CMakeLists.txt

@@ -52,6 +52,10 @@ set(SRCS
   gamepropertiesdialog.cpp
   gamepropertiesdialog.h
   gamepropertiesdialog.ui
+  gdbconnection.cpp
+  gdbconnection.h
+  gdbserver.cpp
+  gdbserver.h
   generalsettingswidget.cpp
   generalsettingswidget.h
   generalsettingswidget.ui

src/duckstation-qt/duckstation-qt.vcxproj

@@ -75,6 +75,8 @@
     <ClCompile Include="gamelistsettingswidget.cpp" />
     <ClCompile Include="gamelistwidget.cpp" />
     <ClCompile Include="gamepropertiesdialog.cpp" />
+    <ClCompile Include="gdbconnection.cpp" />
+    <ClCompile Include="gdbserver.cpp" />
     <ClCompile Include="main.cpp" />
     <ClCompile Include="mainwindow.cpp" />
     <ClCompile Include="controllersettingswidget.cpp" />
@@ -119,6 +121,8 @@
     <QtMoc Include="gamelistsettingswidget.h" />
     <QtMoc Include="gamelistwidget.h" />
     <QtMoc Include="gamepropertiesdialog.h" />
+    <QtMoc Include="gdbconnection.h" />
+    <QtMoc Include="gdbserver.h" />
     <QtMoc Include="postprocessingchainconfigwidget.h" />
     <QtMoc Include="postprocessingshaderconfigwidget.h" />
     <QtMoc Include="postprocessingsettingswidget.h" />
@@ -221,6 +225,8 @@
     <ClCompile Include="$(IntDir)moc_gamelistsettingswidget.cpp" />
     <ClCompile Include="$(IntDir)moc_gamelistwidget.cpp" />
     <ClCompile Include="$(IntDir)moc_gamepropertiesdialog.cpp" />
+    <ClCompile Include="$(IntDir)moc_gdbconnection.cpp" />
+    <ClCompile Include="$(IntDir)moc_gdbserver.cpp" />
     <ClCompile Include="$(IntDir)moc_generalsettingswidget.cpp" />
     <ClCompile Include="$(IntDir)moc_debuggermodels.cpp" />
     <ClCompile Include="$(IntDir)moc_debuggerwindow.cpp" />

src/duckstation-qt/duckstation-qt.vcxproj.filters

@@ -31,6 +31,10 @@
     <ClCompile Include="$(IntDir)moc_advancedsettingswidget.cpp" />
     <ClCompile Include="gamepropertiesdialog.cpp" />
     <ClCompile Include="$(IntDir)moc_gamepropertiesdialog.cpp" />
+    <ClCompile Include="gdbconnection.cpp" />
+    <ClCompile Include="$(IntDir)moc_gdbconnection.cpp" />
+    <ClCompile Include="gdbserver.cpp" />
+    <ClCompile Include="$(IntDir)moc_gdbserver.cpp" />
     <ClCompile Include="controllersettingswidget.cpp" />
     <ClCompile Include="aboutdialog.cpp" />
     <ClCompile Include="memorycardsettingswidget.cpp" />
@@ -101,6 +105,8 @@
     <QtMoc Include="qtprogresscallback.h" />
     <QtMoc Include="advancedsettingswidget.h" />
     <QtMoc Include="gamepropertiesdialog.h" />
+    <QtMoc Include="gdbconnection.h" />
+    <QtMoc Include="gdbserver.h" />
     <QtMoc Include="controllersettingswidget.h" />
     <QtMoc Include="aboutdialog.h" />
     <QtMoc Include="memorycardsettingswidget.h" />

src/duckstation-qt/gdbconnection.cpp

@@ -0,0 +1,82 @@
+#include "gdbconnection.h"
+#include "qthostinterface.h"
+#include "common/log.h"
+#include "core/gdb_protocol.h"
+Log_SetChannel(GDBConnection);
+
+GDBConnection::GDBConnection(QObject *parent, int descriptor)
+  : QThread(parent), m_descriptor(descriptor)
+{
+  Log_InfoPrintf("(%u) Accepted new connection on GDB server", m_descriptor);
+
+  connect(&m_socket, &QTcpSocket::readyRead, this, &GDBConnection::receivedData);
+  connect(&m_socket, &QTcpSocket::disconnected, this, &GDBConnection::gotDisconnected);
+
+  if (m_socket.setSocketDescriptor(m_descriptor)) {
+    QtHostInterface::GetInstance()->pauseSystem(true, true);
+  }
+  else {
+    Log_ErrorPrintf("(%u) Failed to set socket descriptor: %s", m_descriptor, m_socket.errorString().toUtf8().constData());
+  }
+}
+
+void GDBConnection::gotDisconnected()
+{
+  Log_InfoPrintf("(%u) Client disconnected", m_descriptor);
+  this->exit(0);
+}
+
+void GDBConnection::receivedData()
+{
+  qint64 bytesRead;
+  char buffer[256];
+
+  while ((bytesRead = m_socket.read(buffer, sizeof(buffer))) > 0) {
+    for (char c : std::string_view(buffer, bytesRead)) {
+      m_readBuffer.push_back(c);
+
+      if (GDBProtocol::IsPacketInterrupt(m_readBuffer)) {
+        Log_DebugPrintf("(%u) > Interrupt request", m_descriptor);
+        QtHostInterface::GetInstance()->pauseSystem(true, true);
+        m_readBuffer.erase();
+      }
+      else if (GDBProtocol::IsPacketContinue(m_readBuffer)) {
+        Log_DebugPrintf("(%u) > Continue request", m_descriptor);
+        QtHostInterface::GetInstance()->pauseSystem(false, false);
+        m_readBuffer.erase();
+      }
+      else if (GDBProtocol::IsPacketComplete(m_readBuffer)) {
+        Log_DebugPrintf("(%u) > %s", m_descriptor, m_readBuffer.c_str());
+        writePacket(GDBProtocol::ProcessPacket(m_readBuffer));
+        m_readBuffer.erase();
+      }
+    }
+  }
+  if (bytesRead == -1) {
+    Log_ErrorPrintf("(%u) Failed to read from socket: %s", m_descriptor, m_socket.errorString().toUtf8().constData());
+  }
+}
+
+void GDBConnection::onEmulationPaused(bool paused)
+{
+  if (paused) {
+    if (m_seen_resume) {
+      m_seen_resume = false;
+      // Generate a stop reply packet, insert '?' command to generate it.
+      writePacket(GDBProtocol::ProcessPacket("$?#3f"));
+    }
+  }
+  else {
+    m_seen_resume = true;
+    // Send ack, in case GDB sent a continue request.
+    writePacket("+");
+  }
+}
+
+void GDBConnection::writePacket(std::string_view packet)
+{
+  Log_DebugPrintf("(%u) < %*s", m_descriptor, packet.length(), packet.data());
+  if (m_socket.write(packet.data(), packet.length()) == -1) {
+    Log_ErrorPrintf("(%u) Failed to write to socket: %s", m_descriptor, m_socket.errorString().toUtf8().constData());
+  }
+}

src/duckstation-qt/gdbconnection.h

@@ -0,0 +1,24 @@
+#pragma once
+#include <QtCore/QThread>
+#include <QtNetwork/QTcpSocket>
+
+class GDBConnection : public QThread
+{
+  Q_OBJECT
+
+public:
+  GDBConnection(QObject *parent, int descriptor);
+
+public Q_SLOTS:
+  void gotDisconnected();
+  void receivedData();
+  void onEmulationPaused(bool paused);
+
+private:
+  void writePacket(std::string_view data);
+
+  int m_descriptor;
+  QTcpSocket m_socket;
+  std::string m_readBuffer;
+  bool m_seen_resume;
+};

src/duckstation-qt/gdbserver.cpp

@@ -0,0 +1,35 @@
+#include "gdbserver.h"
+#include "gdbconnection.h"
+#include "common/log.h"
+#include "qthostinterface.h"
+Log_SetChannel(GDBServer);
+
+GDBServer::GDBServer(QObject *parent, u16 port)
+    : QTcpServer(parent)
+{
+  if (listen(QHostAddress::LocalHost, port)) {
+    Log_InfoPrintf("GDB server listening on TCP port %u", port);
+  }
+  else {
+    Log_InfoPrintf("Failed to listen on TCP port %u for GDB server: %s", port, errorString().toUtf8().constData());
+  }
+}
+
+GDBServer::~GDBServer()
+{
+  Log_InfoPrint("GDB server stopped");
+  for (auto* thread : m_connections) {
+    thread->quit();
+    thread->wait();
+    delete thread;
+  }
+}
+
+void GDBServer::incomingConnection(qintptr descriptor)
+{
+  Log_InfoPrint("Accepted connection on GDB server");
+  GDBConnection *thread = new GDBConnection(this, descriptor);
+  connect(QtHostInterface::GetInstance(), &QtHostInterface::emulationPaused, thread, &GDBConnection::onEmulationPaused);
+  thread->start();
+  m_connections.push_back(thread);
+}

src/duckstation-qt/gdbserver.h

@@ -0,0 +1,19 @@
+#pragma once
+#include "core/types.h"
+#include "gdbconnection.h"
+#include <QtNetwork/QTcpServer>
+
+class GDBServer : public QTcpServer
+{
+  Q_OBJECT
+
+public:
+  GDBServer(QObject* parent, u16 port);
+  ~GDBServer();
+
+protected:
+  void incomingConnection(qintptr socketDescriptor) override;
+
+private:
+  std::list<GDBConnection*> m_connections;
+};

src/duckstation-qt/mainwindow.cpp

@@ -11,6 +11,7 @@
 #include "gamelistsettingswidget.h"
 #include "gamelistwidget.h"
 #include "gamepropertiesdialog.h"
+#include "gdbserver.h"
 #include "memorycardeditordialog.h"
 #include "qtdisplaywidget.h"
 #include "qthostinterface.h"
@@ -814,6 +815,16 @@ void MainWindow::updateEmulationActions(bool starting, bool running)
     }
   }
 
+  if (g_settings.debugging.enable_gdb_server) {
+    if (starting && !m_gdb_server) {
+      m_gdb_server = new GDBServer(this, g_settings.debugging.gdb_server_port);
+    }
+    else if (!running && m_gdb_server) {
+      delete m_gdb_server;
+      m_gdb_server = nullptr;
+    }
+  }
+
   m_ui.statusBar->clearMessage();
 }
 

src/duckstation-qt/mainwindow.h

@@ -21,6 +21,8 @@ class DebuggerWindow;
 class HostDisplay;
 struct GameListEntry;
 
+class GDBServer;
+
 class MainWindow final : public QMainWindow
 {
   Q_OBJECT
@@ -145,4 +147,6 @@ private:
 
   bool m_emulation_running = false;
   bool m_was_paused_by_focus_loss = false;
+
+  GDBServer* m_gdb_server = nullptr;
 };