HackStudio: Add 'pause debuggee' button

This button sends a SIGSTOP to the debugged process, which pauses it.
The debuggee can be resumed with the 'continue' button.

Userland/DevTools/HackStudio/Debugger/DebugInfoWidget.cpp

@@ -40,12 +40,17 @@ ErrorOr<void> DebugInfoWidget::init_toolbar()
         Debugger::the().set_requested_debugger_action(Debugger::DebuggerAction::SourceStepOut);
     });
 
+    m_pause_action = GUI::Action::create("Pause", {}, TRY(Gfx::Bitmap::load_from_file("/res/icons/16x16/debug-pause.png"sv)), [](auto&) {
+        Debugger::the().stop_debuggee();
+    });
+
     m_toolbar->add_action(*m_continue_action);
     m_toolbar->add_action(*m_singlestep_action);
     m_toolbar->add_action(*m_step_in_action);
     m_toolbar->add_action(*m_step_out_action);
+    m_toolbar->add_action(*m_pause_action);
 
-    set_debug_actions_enabled(false);
+    set_debug_actions_enabled(false, {});
 
     return {};
 }
@@ -193,12 +198,22 @@ void DebugInfoWidget::program_stopped()
     m_registers_view->set_model({});
 }
 
-void DebugInfoWidget::set_debug_actions_enabled(bool enabled)
+void DebugInfoWidget::set_debug_actions_enabled(bool enabled, Optional<DebugActionsState> state)
 {
-    m_continue_action->set_enabled(enabled);
+    if (!enabled) {
-    m_singlestep_action->set_enabled(enabled);
+        m_continue_action->set_enabled(false);
-    m_step_in_action->set_enabled(enabled);
+        m_singlestep_action->set_enabled(false);
-    m_step_out_action->set_enabled(enabled);
+        m_step_in_action->set_enabled(false);
+        m_step_out_action->set_enabled(false);
+        m_pause_action->set_enabled(false);
+        return;
+    }
+
+    m_continue_action->set_enabled(state == DebugActionsState::DebuggeeStopped);
+    m_singlestep_action->set_enabled(state == DebugActionsState::DebuggeeStopped);
+    m_step_in_action->set_enabled(state == DebugActionsState::DebuggeeStopped);
+    m_step_out_action->set_enabled(state == DebugActionsState::DebuggeeStopped);
+    m_pause_action->set_enabled(state == DebugActionsState::DebuggeeRunning);
 }
 
 }

Userland/DevTools/HackStudio/Debugger/DebugInfoWidget.h

@@ -29,7 +29,12 @@ public:
 
     void update_state(Debug::ProcessInspector&, PtraceRegisters const&);
     void program_stopped();
-    void set_debug_actions_enabled(bool enabled);
+
+    enum class DebugActionsState {
+        DebuggeeRunning,
+        DebuggeeStopped,
+    };
+    void set_debug_actions_enabled(bool enabled, Optional<DebugActionsState>);
 
     Function<void(Debug::DebugInfo::SourcePosition const&)> on_backtrace_frame_selection;
 
@@ -51,6 +56,7 @@ private:
     RefPtr<GUI::Action> m_singlestep_action;
     RefPtr<GUI::Action> m_step_in_action;
     RefPtr<GUI::Action> m_step_out_action;
+    RefPtr<GUI::Action> m_pause_action;
 };
 
 }

Userland/DevTools/HackStudio/Debugger/Debugger.cpp

@@ -314,5 +314,9 @@ void Debugger::set_requested_debugger_action(DebuggerAction action)
     pthread_cond_signal(continue_cond());
     pthread_mutex_unlock(continue_mutex());
 }
+void Debugger::stop_debuggee()
+{
+    return m_debug_session->stop_debuggee();
+}
 
 }

Userland/DevTools/HackStudio/Debugger/Debugger.h

@@ -64,6 +64,8 @@ public:
 
     void set_child_setup_callback(Function<ErrorOr<void>()> callback) { m_child_setup_callback = move(callback); }
 
+    void stop_debuggee();
+
 private:
     class DebuggingState {
     public:

Userland/DevTools/HackStudio/HackStudioWidget.cpp

@@ -1055,7 +1055,7 @@ void HackStudioWidget::initialize_debugger()
                 if (m_current_editor_in_execution)
                     m_current_editor_in_execution->editor().set_execution_position(source_position.value().line_number - 1);
                 m_debug_info_widget->update_state(*Debugger::the().session(), regs);
-                m_debug_info_widget->set_debug_actions_enabled(true);
+                m_debug_info_widget->set_debug_actions_enabled(true, DebugInfoWidget::DebugActionsState::DebuggeeStopped);
                 m_disassembly_widget->update_state(*Debugger::the().session(), regs);
                 HackStudioWidget::reveal_action_tab(*m_debug_info_widget);
             });
@@ -1065,7 +1065,7 @@ void HackStudioWidget::initialize_debugger()
         },
         [this]() {
             GUI::Application::the()->event_loop().deferred_invoke([this] {
-                m_debug_info_widget->set_debug_actions_enabled(false);
+                m_debug_info_widget->set_debug_actions_enabled(true, DebugInfoWidget::DebugActionsState::DebuggeeRunning);
                 if (m_current_editor_in_execution)
                     m_current_editor_in_execution->editor().clear_execution_position();
             });
@@ -1073,7 +1073,7 @@ void HackStudioWidget::initialize_debugger()
         },
         [this]() {
             GUI::Application::the()->event_loop().deferred_invoke([this] {
-                m_debug_info_widget->set_debug_actions_enabled(false);
+                m_debug_info_widget->set_debug_actions_enabled(false, {});
                 if (m_current_editor_in_execution)
                     m_current_editor_in_execution->editor().clear_execution_position();
                 m_debug_info_widget->program_stopped();

Userland/Libraries/LibDebug/DebugSession.cpp

@@ -510,4 +510,9 @@ void DebugSession::update_loaded_libs()
     });
 }
 
+void DebugSession::stop_debuggee()
+{
+    kill(pid(), SIGSTOP);
+}
+
 }

Userland/Libraries/LibDebug/DebugSession.h

@@ -100,6 +100,7 @@ public:
         Syscall,
     };
     void continue_debuggee(ContinueType type = ContinueType::FreeRun);
+    void stop_debuggee();
 
     // Returns the wstatus result of waitpid()
     int continue_debuggee_and_wait(ContinueType type = ContinueType::FreeRun);
@@ -169,7 +170,7 @@ void DebugSession::run(DesiredInitialDebugeeState initial_debugee_state, Callbac
 
         // FIXME: This check actually only checks whether the debuggee
         // stopped because it hit a breakpoint/syscall/is in single stepping mode or not
-        if (WSTOPSIG(wstatus) != SIGTRAP) {
+        if (WSTOPSIG(wstatus) != SIGTRAP && WSTOPSIG(wstatus) != SIGSTOP) {
             callback(DebugBreakReason::Exited, Optional<PtraceRegisters>());
             m_is_debuggee_dead = true;
             return true;