// SPDX-FileCopyrightText: Copyright 2022 yuzu Emulator Project
// SPDX-License-Identifier: GPL-2.0-or-later
#include <algorithm>
#include <mutex>
#include <thread>
#include <boost/asio.hpp>
#include <boost/process/async_pipe.hpp>
#include "common/logging/log.h"
#include "common/thread.h"
#include "core/core.h"
#include "core/debugger/debugger.h"
#include "core/debugger/debugger_interface.h"
#include "core/debugger/gdbstub.h"
#include "core/hle/kernel/global_scheduler_context.h"
#include "core/hle/kernel/k_scheduler.h"
template <typename Readable, typename Buffer, typename Callback>
static void AsyncReceiveInto(Readable& r, Buffer& buffer, Callback&& c) {
static_assert(std::is_trivial_v<Buffer>);
auto boost_buffer{boost::asio::buffer(&buffer, sizeof(Buffer))};
r.async_read_some(
boost_buffer, [&, c](const boost::system::error_code& error, size_t bytes_read) {
if (!error.failed()) {
const u8* buffer_start = reinterpret_cast<const u8*>(&buffer);
std::span<const u8> received_data{buffer_start, buffer_start + bytes_read};
c(received_data);
}
AsyncReceiveInto(r, buffer, c);
});
}
template <typename Readable, typename Buffer>
static std::span<const u8> ReceiveInto(Readable& r, Buffer& buffer) {
static_assert(std::is_trivial_v<Buffer>);
auto boost_buffer{boost::asio::buffer(&buffer, sizeof(Buffer))};
size_t bytes_read = r.read_some(boost_buffer);
const u8* buffer_start = reinterpret_cast<const u8*>(&buffer);
std::span<const u8> received_data{buffer_start, buffer_start + bytes_read};
return received_data;
}
enum class SignalType {
Stopped,
Watchpoint,
ShuttingDown,
};
struct SignalInfo {
SignalType type;
Kernel::KThread* thread;
const Kernel::DebugWatchpoint* watchpoint;
};
namespace Core {
class DebuggerImpl : public DebuggerBackend {
public:
explicit DebuggerImpl(Core::System& system_, u16 port)
: system{system_}, signal_pipe{io_context}, client_socket{io_context} {
frontend = std::make_unique<GDBStub>(*this, system);
InitializeServer(port);
}
~DebuggerImpl() override {
ShutdownServer();
}
bool SignalDebugger(SignalInfo signal_info) {
{
std::scoped_lock lk{connection_lock};
if (stopped) {
// Do not notify the debugger about another event.
// It should be ignored.
return false;
}
// Set up the state.
stopped = true;
info = signal_info;
}
// Write a single byte into the pipe to wake up the debug interface.
boost::asio::write(signal_pipe, boost::asio::buffer(&stopped, sizeof(stopped)));
return true;
}
std::span<const u8> ReadFromClient() override {
return ReceiveInto(client_socket, client_data);
}
void WriteToClient(std::span<const u8> data) override {
boost::asio::write(client_socket, boost::asio::buffer(data.data(), data.size_bytes()));
}
void SetActiveThread(Kernel::KThread* thread) override {
active_thread = thread;
}
Kernel::KThread* GetActiveThread() override {
return active_thread;
}
private:
void InitializeServer(u16 port) {
using boost::asio::ip::tcp;
LOG_INFO(Debug_GDBStub, "Starting server on port {}...", port);
// Run the connection thread.
connection_thread = std::jthread([&, port](std::stop_token stop_token) {
try {
// Initialize the listening socket and accept a new client.
tcp::endpoint endpoint{boost::asio::ip::address_v4::any(), port};
tcp::acceptor acceptor{io_context, endpoint};
acceptor.async_accept(client_socket, [](const auto&) {});
io_context.run_one();
io_context.restart();
if (stop_token.stop_requested()) {
return;
}
ThreadLoop(stop_token);
} catch (const std::exception& ex) {
LOG_CRITICAL(Debug_GDBStub, "Stopping server: {}", ex.what());
}
});
}
void ShutdownServer() {
connection_thread.request_stop();
io_context.stop();
connection_thread.join();
}
void ThreadLoop(std::stop_token stop_token) {
Common::SetCurrentThreadName("Debugger");
// Set up the client signals for new data.
AsyncReceiveInto(signal_pipe, pipe_data, [&](auto d) { PipeData(d); });
AsyncReceiveInto(client_socket, client_data, [&](auto d) { ClientData(d); });
// Set the active thread.
UpdateActiveThread();
// Set up the frontend.
frontend->Connected();
// Main event loop.
while (!stop_token.stop_requested() && io_context.run()) {
}
}
void PipeData(std::span<const u8> data) {
switch (info.type) {
case SignalType::Stopped:
case SignalType::Watchpoint:
// Stop emulation.
PauseEmulation();
// Notify the client.
active_thread = info.thread;
UpdateActiveThread();
if (info.type == SignalType::Watchpoint) {
frontend->Watchpoint(active_thread, *info.watchpoint);
} else {
frontend->Stopped(active_thread);
}
break;
case SignalType::ShuttingDown:
frontend->ShuttingDown();
// Wait for emulation to shut down gracefully now.
signal_pipe.close();
client_socket.shutdown(boost::asio::socket_base::shutdown_both);
LOG_INFO(Debug_GDBStub, "Shut down server");
break;
}
}
void ClientData(std::span<const u8> data) {
const auto actions{frontend->ClientData(data)};
for (const auto action : actions) {
switch (action) {
case DebuggerAction::Interrupt: {
{
std::scoped_lock lk{connection_lock};
stopped = true;
}
PauseEmulation();
UpdateActiveThread();
frontend->Stopped(active_thread);
break;
}
case DebuggerAction::Continue:
MarkResumed([&] { ResumeEmulation(); });
break;
case DebuggerAction::StepThreadUnlocked:
MarkResumed([&] {
active_thread->SetStepState(Kernel::StepState::StepPending);
active_thread->Resume(Kernel::SuspendType::Debug);
ResumeEmulation(active_thread);
});
break;
case DebuggerAction::StepThreadLocked: {
MarkResumed([&] {
active_thread->SetStepState(Kernel::StepState::StepPending);
active_thread->Resume(Kernel::SuspendType::Debug);
});
break;
}
case DebuggerAction::ShutdownEmulation: {
// Spawn another thread that will exit after shutdown,
// to avoid a deadlock
Core::System* system_ref{&system};
std::thread t([system_ref] { system_ref->Exit(); });
t.detach();
break;
}
}
}
}
void PauseEmulation() {
Kernel::KScopedSchedulerLock sl{system.Kernel()};
// Put all threads to sleep on next scheduler round.
for (auto* thread : ThreadList()) {
thread->RequestSuspend(Kernel::SuspendType::Debug);
}
}
void ResumeEmulation(Kernel::KThread* except = nullptr) {
// Wake up all threads.
for (auto* thread : ThreadList()) {
if (thread == except) {
continue;
}
thread->SetStepState(Kernel::StepState::NotStepping);
thread->Resume(Kernel::SuspendType::Debug);
}
}
template <typename Callback>
void MarkResumed(Callback&& cb) {
Kernel::KScopedSchedulerLock sl{system.Kernel()};
std::scoped_lock cl{connection_lock};
stopped = false;
cb();
}
void UpdateActiveThread() {
const auto& threads{ThreadList()};
if (std::find(threads.begin(), threads.end(), active_thread) == threads.end()) {
active_thread = threads[0];
}
}
const std::vector<Kernel::KThread*>& ThreadList() {
return system.GlobalSchedulerContext().GetThreadList();
}
private:
System& system;
std::unique_ptr<DebuggerFrontend> frontend;
std::jthread connection_thread;
std::mutex connection_lock;
boost::asio::io_context io_context;
boost::process::async_pipe signal_pipe;
boost::asio::ip::tcp::socket client_socket;
SignalInfo info;
Kernel::KThread* active_thread;
bool pipe_data;
bool stopped;
std::array<u8, 4096> client_data;
};
Debugger::Debugger(Core::System& system, u16 port) {
try {
impl = std::make_unique<DebuggerImpl>(system, port);
} catch (const std::exception& ex) {
LOG_CRITICAL(Debug_GDBStub, "Failed to initialize debugger: {}", ex.what());
}
}
Debugger::~Debugger() = default;
bool Debugger::NotifyThreadStopped(Kernel::KThread* thread) {
return impl && impl->SignalDebugger(SignalInfo{SignalType::Stopped, thread, nullptr});
}
bool Debugger::NotifyThreadWatchpoint(Kernel::KThread* thread,
const Kernel::DebugWatchpoint& watch) {
return impl && impl->SignalDebugger(SignalInfo{SignalType::Watchpoint, thread, &watch});
}
void Debugger::NotifyShutdown() {
if (impl) {
impl->SignalDebugger(SignalInfo{SignalType::ShuttingDown, nullptr, nullptr});
}
}
} // namespace Core
