Error checking for Stdio calls

runtime/bin/stdio_linux.cc

Index: runtime/bin/stdio_linux.cc
diff --git a/runtime/bin/stdio_linux.cc b/runtime/bin/stdio_linux.cc
index 280c75fe7df45ddcf3dded883031cfd7ffc47b30..dd61fae84348dc5796674adf4dc612cb18794b88 100644
--- a/runtime/bin/stdio_linux.cc
+++ b/runtime/bin/stdio_linux.cc
@@ -19,50 +19,67 @@
 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);
 }