Improve UNIX signal handling (#518)

There was a dead lock caused by the reentrancy of the post method.

Co-authored-by: ArthurSonzogni <sonzogniarthur@gmail.com>
This commit is contained in:
mr-mocap 2022-12-01 16:56:35 -05:00 committed by GitHub
parent 05f29ff3b3
commit f21ca3aa14
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GPG Key ID: 4AEE18F83AFDEB23
2 changed files with 140 additions and 72 deletions

View File

@ -52,6 +52,8 @@ class ScreenInteractive : public Screen {
Closure WithRestoredIO(Closure);
private:
void ExitNow();
void Install();
void Uninstall();
@ -64,8 +66,9 @@ class ScreenInteractive : public Screen {
void HandleTask(Component component, Task& task);
void Draw(Component component);
void ResetCursorPosition();
void SigStop();
void Signal(int signal);
ScreenInteractive* suspended_screen_ = nullptr;
enum class Dimension {
@ -106,7 +109,7 @@ class ScreenInteractive : public Screen {
public:
class Private {
public:
static void SigStop(ScreenInteractive& s) { return s.SigStop(); }
static void Signal(ScreenInteractive& s, int signal) { s.Signal(signal); }
};
friend Private;
};

View File

@ -148,7 +148,8 @@ void ftxui_on_resize(int columns, int rows) {
}
}
#else
#else // POSIX (Linux & Mac)
#include <sys/time.h> // for timeval
int CheckStdinReady(int usec_timeout) {
@ -178,9 +179,74 @@ void EventListener(std::atomic<bool>* quit, Sender<Task> out) {
}
}
}
#endif
std::stack<Closure> on_exit_functions; // NOLINT
void OnExit() {
while (!on_exit_functions.empty()) {
on_exit_functions.top()();
on_exit_functions.pop();
}
}
std::atomic<int> g_signal_exit_count = 0;
#if !defined(_WIN32)
std::atomic<int> g_signal_stop_count = 0;
std::atomic<int> g_signal_resize_count = 0;
#endif
// Async signal safe function
void RecordSignal(int signal) {
switch (signal) {
case SIGABRT:
case SIGFPE:
case SIGILL:
case SIGINT:
case SIGSEGV:
case SIGTERM:
g_signal_exit_count++;
break;
#if !defined(_WIN32)
case SIGTSTP:
g_signal_stop_count++;
break;
case SIGWINCH:
g_signal_resize_count++;
break;
#endif
default:
break;
}
}
void ExecuteSignalHandlers() {
int signal_exit_count = g_signal_exit_count.exchange(0);
while (signal_exit_count--) {
ScreenInteractive::Private::Signal(*g_active_screen, SIGABRT);
}
#if !defined(_WIN32)
int signal_stop_count = g_signal_stop_count.exchange(0);
while (signal_stop_count--) {
ScreenInteractive::Private::Signal(*g_active_screen, SIGTSTP);
}
int signal_resize_count = g_signal_resize_count.exchange(0);
while (signal_resize_count--) {
ScreenInteractive::Private::Signal(*g_active_screen, SIGWINCH);
}
#endif
}
void InstallSignalHandler(int sig) {
auto old_signal_handler = std::signal(sig, RecordSignal);
on_exit_functions.push(
[=] { std::ignore = std::signal(sig, old_signal_handler); });
};
const std::string CSI = "\x1b["; // NOLINT
// DEC: Digital Equipment Corporation
@ -230,31 +296,6 @@ std::string DeviceStatusReport(DSRMode ps) {
return CSI + std::to_string(int(ps)) + "n";
}
using SignalHandler = void(int);
std::stack<Closure> on_exit_functions; // NOLINT
void OnExit(int signal) {
(void)signal;
while (!on_exit_functions.empty()) {
on_exit_functions.top()();
on_exit_functions.pop();
}
}
const auto install_signal_handler = [](int sig, SignalHandler handler) {
auto old_signal_handler = std::signal(sig, handler);
on_exit_functions.push(
[=] { std::ignore = std::signal(sig, old_signal_handler); });
};
Closure g_on_resize = [] {}; // NOLINT
void OnResize(int /* signal */) {
g_on_resize();
}
void OnSigStop(int /*signal*/) {
ScreenInteractive::Private::SigStop(*g_active_screen);
}
class CapturedMouseImpl : public CapturedMouseInterface {
public:
explicit CapturedMouseImpl(std::function<void(void)> callback)
@ -378,10 +419,13 @@ void ScreenInteractive::PreMain() {
// Suspend previously active screen:
if (g_active_screen) {
std::swap(suspended_screen_, g_active_screen);
std::cout << suspended_screen_->reset_cursor_position
<< suspended_screen_->ResetPosition(/*clear=*/true);
// Reset cursor position to the top of the screen and clear the screen.
suspended_screen_->ResetCursorPosition();
std::cout << suspended_screen_->ResetPosition(/*clear=*/true);
suspended_screen_->dimx_ = 0;
suspended_screen_->dimy_ = 0;
// Reset dimensions to force drawing the screen again next time:
suspended_screen_->Uninstall();
}
@ -393,20 +437,22 @@ void ScreenInteractive::PreMain() {
}
void ScreenInteractive::PostMain() {
g_active_screen->Uninstall();
g_active_screen = nullptr;
// Put cursor position at the end of the drawing.
std::cout << reset_cursor_position;
ResetCursorPosition();
g_active_screen = nullptr;
// Restore suspended screen.
if (suspended_screen_) {
// Clear screen, and put the cursor at the beginning of the drawing.
std::cout << ResetPosition(/*clear=*/true);
dimx_ = 0;
dimy_ = 0;
Uninstall();
std::swap(g_active_screen, suspended_screen_);
g_active_screen->Install();
} else {
Uninstall();
// On final exit, keep the current drawing and reset cursor position one
// line after it.
std::cout << std::endl;
@ -430,6 +476,8 @@ ScreenInteractive* ScreenInteractive::Active() {
}
void ScreenInteractive::Install() {
frame_valid_ = false;
// After uninstalling the new configuration, flush it to the terminal to
// ensure it is fully applied:
on_exit_functions.push([] { Flush(); });
@ -439,10 +487,10 @@ void ScreenInteractive::Install() {
// Install signal handlers to restore the terminal state on exit. The default
// signal handlers are restored on exit.
for (int signal : {SIGTERM, SIGSEGV, SIGINT, SIGILL, SIGABRT, SIGFPE}) {
install_signal_handler(signal, OnExit);
InstallSignalHandler(signal);
}
// Save the old terminal configuration and restore it on exit.
// Save the old terminal configuration and restore it on exit.
#if defined(_WIN32)
// Enable VT processing on stdout and stdin
auto stdout_handle = GetStdHandle(STD_OUTPUT_HANDLE);
@ -474,6 +522,10 @@ void ScreenInteractive::Install() {
SetConsoleMode(stdin_handle, in_mode);
SetConsoleMode(stdout_handle, out_mode);
#else
for (int signal : {SIGWINCH, SIGTSTP}) {
InstallSignalHandler(signal);
}
struct termios terminal; // NOLINT
tcgetattr(STDIN_FILENO, &terminal);
on_exit_functions.push([=] { tcsetattr(STDIN_FILENO, TCSANOW, &terminal); });
@ -488,12 +540,6 @@ void ScreenInteractive::Install() {
tcsetattr(STDIN_FILENO, TCSANOW, &terminal);
// Handle resize.
g_on_resize = [&] { task_sender_->Send(Event::Special({0})); };
install_signal_handler(SIGWINCH, OnResize);
// Handle SIGTSTP/SIGCONT.
install_signal_handler(SIGTSTP, OnSigStop);
#endif
auto enable = [&](const std::vector<DECMode>& parameters) {
@ -518,7 +564,7 @@ void ScreenInteractive::Install() {
});
disable({
//DECMode::kCursor,
// DECMode::kCursor,
DECMode::kLineWrap,
});
@ -529,8 +575,8 @@ void ScreenInteractive::Install() {
DECMode::kMouseSgrExtMode,
});
// After installing the new configuration, flush it to the terminal to ensure
// it is fully applied:
// After installing the new configuration, flush it to the terminal to
// ensure it is fully applied:
Flush();
quit_ = false;
@ -542,28 +588,27 @@ void ScreenInteractive::Install() {
}
void ScreenInteractive::Uninstall() {
ExitLoopClosure()();
ExitNow();
event_listener_.join();
animation_listener_.join();
OnExit(0);
OnExit();
}
// NOLINTNEXTLINE
void ScreenInteractive::RunOnceBlocking(Component component) {
ExecuteSignalHandlers();
Task task;
if (task_receiver_->Receive(&task)) {
HandleTask(component, task);
}
RunOnce(component);
}
// NOLINTNEXTLINE
void ScreenInteractive::RunOnce(Component component) {
Task task;
while (task_receiver_->ReceiveNonBlocking(&task)) {
HandleTask(component, task);
ExecuteSignalHandlers();
}
Draw(std::move(component));
}
@ -650,7 +695,8 @@ void ScreenInteractive::Draw(Component component) {
}
bool resized = (dimx != dimx_) || (dimy != dimy_);
std::cout << reset_cursor_position << ResetPosition(/*clear=*/resized);
ResetCursorPosition();
std::cout << ResetPosition(/*clear=*/resized);
// Resize the screen if needed.
if (resized) {
@ -710,7 +756,8 @@ void ScreenInteractive::Draw(Component component) {
set_cursor_position += "\033[?25l";
} else {
set_cursor_position += "\033[?25h";
set_cursor_position += "\033[" + std::to_string(int(cursor_.shape)) + " q";
set_cursor_position +=
"\033[" + std::to_string(int(cursor_.shape)) + " q";
}
}
@ -720,32 +767,50 @@ void ScreenInteractive::Draw(Component component) {
frame_valid_ = true;
}
void ScreenInteractive::ResetCursorPosition() {
std::cout << reset_cursor_position;
reset_cursor_position = "";
}
Closure ScreenInteractive::ExitLoopClosure() {
return [this] { Exit(); };
}
void ScreenInteractive::Exit() {
Post([this] {
quit_ = true;
task_sender_.reset();
});
Post([this] { ExitNow(); });
}
void ScreenInteractive::SigStop() {
#if defined(_WIN32)
// Windows do no support SIGTSTP.
#else
Post([&] {
Uninstall();
std::cout << reset_cursor_position;
reset_cursor_position = "";
std::cout << ResetPosition(/*clear=*/true);
dimx_ = 0;
dimy_ = 0;
Flush();
std::ignore = std::raise(SIGTSTP);
Install();
});
void ScreenInteractive::ExitNow() {
quit_ = true;
task_sender_.reset();
}
void ScreenInteractive::Signal(int signal) {
if (signal == SIGABRT) {
OnExit();
return;
}
// Windows do no support SIGTSTP / SIGWINCH
#if !defined(_WIN32)
if (signal == SIGTSTP) {
Post([&] {
ResetCursorPosition();
std::cout << ResetPosition(/*clear*/ true); // Cursor to the beginning
Uninstall();
dimx_ = 0;
dimy_ = 0;
Flush();
std::ignore = std::raise(SIGTSTP);
Install();
});
return;
}
if (signal == SIGWINCH) {
Post(Event::Special({0}));
return;
}
#endif
}