Revert "src: restore stdio on program exit"

This reverts commit c2c9c0c.
It seems to be causing hangs when piping output to other processes.

PR-URL: #21257
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>

src/node.cc

@@ -100,7 +100,6 @@ typedef int mode_t;
 #else
 #include <pthread.h>
 #include <sys/resource.h>  // getrlimit, setrlimit
-#include <termios.h>  // tcgetattr, tcsetattr
 #include <unistd.h>  // setuid, getuid
 #endif
 
@@ -173,9 +172,6 @@ using v8::Value;
 static Mutex process_mutex;
 static Mutex environ_mutex;
 
-// Safe to call more than once and from signal handlers.
-inline void PlatformExit();
-
 static bool print_eval = false;
 static bool force_repl = false;
 static bool syntax_check_only = false;
@@ -886,7 +882,7 @@ void AppendExceptionLine(Environment* env,
     Mutex::ScopedLock lock(process_mutex);
     env->set_printed_error(true);
 
-    PlatformExit();
+    uv_tty_reset_mode();
     PrintErrorString("\n%s", arrow);
     return;
   }
@@ -2797,7 +2793,7 @@ void SetupProcessObject(Environment* env,
 
 
 void SignalExit(int signo) {
-  PlatformExit();
+  uv_tty_reset_mode();
   v8_platform.StopTracingAgent();
 #ifdef __FreeBSD__
   // FreeBSD has a nasty bug, see RegisterSignalHandler for details
@@ -3629,27 +3625,6 @@ static void DebugEnd(const FunctionCallbackInfo<Value>& args) {
 }
 
 
-#ifdef __POSIX__
-static struct {
-  int flags;
-  bool isatty;
-  struct stat stat;
-  struct termios termios;
-} stdio[1 + STDERR_FILENO];
-
-
-inline int GetFileDescriptorFlags(int fd) {
-  int flags;
-
-  do {
-    flags = fcntl(fd, F_GETFL);
-  } while (flags == -1 && errno == EINTR);
-
-  return flags;
-}
-#endif  // __POSIX__
-
-
 inline void PlatformInit() {
 #ifdef __POSIX__
 #if HAVE_INSPECTOR
@@ -3660,18 +3635,16 @@ inline void PlatformInit() {
 #endif  // HAVE_INSPECTOR
 
   // Make sure file descriptors 0-2 are valid before we start logging anything.
-  for (auto& s : stdio) {
-    const int fd = &s - stdio;
-    if (fstat(fd, &s.stat) == 0)
+  for (int fd = STDIN_FILENO; fd <= STDERR_FILENO; fd += 1) {
+    struct stat ignored;
+    if (fstat(fd, &ignored) == 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
@@ -3694,24 +3667,6 @@ 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;
-
-    s.flags = GetFileDescriptorFlags(fd);
-    CHECK_NE(s.flags, -1);
-
-    if (!isatty(fd)) continue;
-    s.isatty = true;
-    do {
-      err = tcgetattr(fd, &s.termios);
-    } while (err == -1 && errno == EINTR);
-    CHECK_EQ(err, 0);
-  }
-
   RegisterSignalHandler(SIGINT, SignalExit, true);
   RegisterSignalHandler(SIGTERM, SignalExit, true);
 
@@ -3752,49 +3707,6 @@ inline void PlatformInit() {
 }
 
 
-// This function must be safe to call more than once and from signal handlers.
-inline void PlatformExit() {
-#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 = GetFileDescriptorFlags(fd);
-    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);
-      CHECK_NE(err, -1);
-    }
-
-    if (s.isatty) {
-      int err;
-      do {
-        err = tcsetattr(fd, TCSANOW, &s.termios);
-      } while (err == -1 && errno == EINTR);
-      CHECK_NE(err, -1);
-    }
-  }
-#endif  // __POSIX__
-}
-
-
 void ProcessArgv(int* argc,
                  const char** argv,
                  int* exec_argc,
@@ -4266,7 +4178,7 @@ inline int Start(uv_loop_t* event_loop,
 }
 
 int Start(int argc, char** argv) {
-  atexit([] () { PlatformExit(); });
+  atexit([] () { uv_tty_reset_mode(); });
   PlatformInit();
   performance::performance_node_start = PERFORMANCE_NOW();