Error checking for Stdio calls

runtime/bin/stdio_linux.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #if !defined(DART_IO_DISABLED)
 
 #include "platform/globals.h"
 #if defined(TARGET_OS_LINUX)
 
 #include "bin/stdio.h"
 
 #include <errno.h>      // NOLINT
 #include <sys/ioctl.h>  // NOLINT
 #include <termios.h>    // NOLINT
 
 #include "bin/fdutils.h"
 #include "platform/signal_blocker.h"
 
 namespace dart {
 namespace bin {
 
-int Stdin::ReadByte() {
+bool Stdin::ReadByte(int* byte) {
   int c = NO_RETRY_EXPECTED(getchar());
-  if (c == EOF) {
-    c = -1;
+  if ((c == EOF) && (errno != 0)) {
+    return false;
   }
-  return c;
+  *byte = (c == EOF) ? -1 : c;
+  return true;
 }
 
 
-bool Stdin::GetEchoMode() {
+bool Stdin::GetEchoMode(bool* enabled) {
   struct termios term;
-  VOID_NO_RETRY_EXPECTED(tcgetattr(STDIN_FILENO, &term));
-  return ((term.c_lflag & ECHO) != 0);
+  int status = NO_RETRY_EXPECTED(tcgetattr(STDIN_FILENO, &term));
+  if (status != 0) {
+    return false;
+  }
+  *enabled = ((term.c_lflag & ECHO) != 0);
+  return true;
 }
 
 
-void Stdin::SetEchoMode(bool enabled) {
+bool Stdin::SetEchoMode(bool enabled) {
   struct termios term;
-  VOID_NO_RETRY_EXPECTED(tcgetattr(STDIN_FILENO, &term));
+  int status = NO_RETRY_EXPECTED(tcgetattr(STDIN_FILENO, &term));
+  if (status != 0) {
+    return false;
+  }
   if (enabled) {
     term.c_lflag |= (ECHO | ECHONL);
   } else {
     term.c_lflag &= ~(ECHO | ECHONL);
   }
-  VOID_NO_RETRY_EXPECTED(tcsetattr(STDIN_FILENO, TCSANOW, &term));
+  status = NO_RETRY_EXPECTED(tcsetattr(STDIN_FILENO, TCSANOW, &term));
+  return (status == 0);
 }
 
 
-bool Stdin::GetLineMode() {
+bool Stdin::GetLineMode(bool* enabled) {
   struct termios term;
-  VOID_NO_RETRY_EXPECTED(tcgetattr(STDIN_FILENO, &term));
-  return ((term.c_lflag & ICANON) != 0);
+  int status = NO_RETRY_EXPECTED(tcgetattr(STDIN_FILENO, &term));
+  if (status != 0) {
+    return false;
+  }
+  *enabled = ((term.c_lflag & ICANON) != 0);
+  return true;
 }
 
 
-void Stdin::SetLineMode(bool enabled) {
+bool Stdin::SetLineMode(bool enabled) {
   struct termios term;
-  VOID_NO_RETRY_EXPECTED(tcgetattr(STDIN_FILENO, &term));
+  int status = NO_RETRY_EXPECTED(tcgetattr(STDIN_FILENO, &term));
+  if (status != 0) {
+    return false;
+  }
   if (enabled) {
     term.c_lflag |= ICANON;
   } else {
     term.c_lflag &= ~(ICANON);
   }
-  VOID_NO_RETRY_EXPECTED(tcsetattr(STDIN_FILENO, TCSANOW, &term));
+  status = NO_RETRY_EXPECTED(tcsetattr(STDIN_FILENO, TCSANOW, &term));
+  return (status == 0);
 }
 
 
 bool Stdout::GetTerminalSize(intptr_t fd, int size[2]) {
   struct winsize w;
   int status = NO_RETRY_EXPECTED(ioctl(fd, TIOCGWINSZ, &w));
   if ((status == 0) && ((w.ws_col != 0) || (w.ws_row != 0))) {
     size[0] = w.ws_col;
     size[1] = w.ws_row;
     return true;
   }
   return false;
 }
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_LINUX)
 
 #endif  // !defined(DART_IO_DISABLED)