src: restore stdio on program exit

src/node.cc

@@ -103,6 +103,7 @@
 #else
 #include <pthread.h>
 #include <sys/resource.h> // getrlimit, setrlimit
+#include <termios.h> // tcgetattr, tcsetattr
 #include <unistd.h> // STDIN_FILENO, STDERR_FILENO
 #endif
 
@@ -191,7 +192,7 @@ void WaitForInspectorDisconnect(Environment* env) {
 
 #ifdef __POSIX__
 void SignalExit(int signo, siginfo_t* info, void* ucontext) {
-uv_tty_reset_mode();
+ResetStdio();
  raise(signo);
 }
 #endif // __POSIX__
@@ -451,7 +452,7 @@ void TrapWebAssemblyOrContinue(int signo, siginfo_t* info, void* ucontext) {
  if (prev != nullptr) {
  prev(signo, info, ucontext);
  } else {
-uv_tty_reset_mode();
+ResetStdio();
  raise(signo);
  }
  }
@@ -481,6 +482,16 @@ void RegisterSignalHandler(int signal,
 
 #endif // __POSIX__
 
+#ifdef __POSIX__
+static struct {
+ int flags;
+ bool isatty;
+ struct stat stat;
+ struct termios termios;
+} stdio[1 + STDERR_FILENO];
+#endif // __POSIX__
+
+
 inline void PlatformInit() {
 #ifdef __POSIX__
 #if HAVE_INSPECTOR
@@ -491,16 +502,18 @@ inline void PlatformInit() {
 #endif // HAVE_INSPECTOR
 
  // Make sure file descriptors 0-2 are valid before we start logging anything.
- for (int fd = STDIN_FILENO; fd <= STDERR_FILENO; fd += 1) {
-struct stat ignored;
- if (fstat(fd, &ignored) == 0)
+ for (auto& s : stdio) {
+const int fd = &s - stdio;
+ if (fstat(fd, &s.stat) == 0)
  continue;
  // Anything but EBADF means something is seriously wrong. We don't
  // have to special-case EINTR, fstat() is not interruptible.
  if (errno != EBADF)
  ABORT();
  if (fd != open("/dev/null", O_RDWR))
  ABORT();
+ if (fstat(fd, &s.stat) != 0)
+ ABORT();
  }
 
 #if HAVE_INSPECTOR
@@ -523,6 +536,27 @@ inline void PlatformInit() {
  }
 #endif // !NODE_SHARED_MODE
 
+ // Record the state of the stdio file descriptors so we can restore it
+ // on exit. Needs to happen before installing signal handlers because
+ // they make use of that information.
+ for (auto& s : stdio) {
+ const int fd = &s - stdio;
+ int err;
+
+ do
+ s.flags = fcntl(fd, F_GETFL);
+ while (s.flags == -1 && errno == EINTR); // NOLINT
+ CHECK_NE(s.flags, -1);
+
+ if (!isatty(fd)) continue;
+ s.isatty = true;
+
+ do
+ err = tcgetattr(fd, &s.termios);
+ while (err == -1 && errno == EINTR); // NOLINT
+ CHECK_EQ(err, 0);
+ }
+
  RegisterSignalHandler(SIGINT, SignalExit, true);
  RegisterSignalHandler(SIGTERM, SignalExit, true);
 
@@ -576,6 +610,54 @@ inline void PlatformInit() {
 #endif // _WIN32
 }
 
+
+// Safe to call more than once and from signal handlers.
+void ResetStdio() {
+ uv_tty_reset_mode();
+#ifdef __POSIX__
+ for (auto& s : stdio) {
+ const int fd = &s - stdio;
+
+ struct stat tmp;
+ if (-1 == fstat(fd, &tmp)) {
+ CHECK_EQ(errno, EBADF); // Program closed file descriptor.
+ continue;
+ }
+
+ bool is_same_file =
+ (s.stat.st_dev == tmp.st_dev && s.stat.st_ino == tmp.st_ino);
+ if (!is_same_file) continue; // Program reopened file descriptor.
+
+ int flags;
+ do
+ flags = fcntl(fd, F_GETFL);
+ while (flags == -1 && errno == EINTR); // NOLINT
+ CHECK_NE(flags, -1);
+
+ // Restore the O_NONBLOCK flag if it changed.
+ if (O_NONBLOCK & (flags ^ s.flags)) {
+ flags &= ~O_NONBLOCK;
+ flags |= s.flags & O_NONBLOCK;
+
+ int err;
+ do
+ err = fcntl(fd, F_SETFL, flags);
+ while (err == -1 && errno == EINTR); // NOLINT
+ CHECK_NE(err, -1);
+ }
+
+ if (s.isatty) {
+ int err;
+ do
+ err = tcsetattr(fd, TCSANOW, &s.termios);
+ while (err == -1 && errno == EINTR); // NOLINT
+ CHECK_NE(err, -1);
+ }
+ }
+#endif // __POSIX__
+}
+
+
 int ProcessGlobalArgs(std::vector<std::string>* args,
  std::vector<std::string>* exec_args,
  std::vector<std::string>* errors,
@@ -831,7 +913,7 @@ void Init(int* argc,
 }
 
 InitializationResult InitializeOncePerProcess(int argc, char** argv) {
- atexit([] () { uv_tty_reset_mode(); });
+ atexit(ResetStdio);
  PlatformInit();
  per_process::node_start_time = uv_hrtime();
 

src/node_errors.cc

@@ -229,7 +229,7 @@ void AppendExceptionLine(Environment* env,
  Mutex::ScopedLock lock(per_process::tty_mutex);
  env->set_printed_error(true);
 
-uv_tty_reset_mode();
+ResetStdio();
  PrintErrorString("\n%s", source.c_str());
  return;
  }

src/node_internals.h

@@ -91,6 +91,7 @@ void PrintCaughtException(v8::Isolate* isolate,
  const v8::TryCatch& try_catch);
 
 void WaitForInspectorDisconnect(Environment* env);
+void ResetStdio(); // Safe to call more than once and from signal handlers.
 #ifdef __POSIX__
 void SignalExit(int signal, siginfo_t* info, void* ucontext);
 #endif

src/node_main_instance.cc

@@ -145,7 +145,7 @@ int NodeMainInstance::Run() {
 
  env->set_can_call_into_js(false);
  env->stop_sub_worker_contexts();
-uv_tty_reset_mode();
+ResetStdio();
  env->RunCleanup();
  RunAtExit(env.get());