Make RouteStdioToConsole() redirect FDs 1 and 2 as well as FILE* pointers

After this change, --enable-logging allows NaCl untrusted code to
output to stdout/stderr when Chrome is running under the Windows
console, which makes debugging easier.  The change is needed because
NaCl uses _write() on file descriptors 1 and 2 in this case rather
than fwrite() on FILE* stdout and stderr.

stdout/stderr already worked for NaCl untrusted code on Linux and Mac.

BUG=171836
TEST=manually run hello_world.nexe under Chrome on a Windows console


Review URL: https://chromiumcodereview.appspot.com/12095018

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@179613 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 11 insertions, 2 deletions

diff --git a/base/process_util_win.cc b/base/process_util_win.cc
index 4355b15..2a47f13 100644
--- a/base/process_util_win.cc
+++ b/base/process_util_win.cc
@@ -160,10 +160,19 @@ void RouteStdioToConsole() {
   // log-lines in output.
   enum { kOutputBufferSize = 64 * 1024 };
 
-  if (freopen("CONOUT$", "w", stdout))
+  if (freopen("CONOUT$", "w", stdout)) {
     setvbuf(stdout, NULL, _IOLBF, kOutputBufferSize);
-  if (freopen("CONOUT$", "w", stderr))
+    // Overwrite FD 1 for the benefit of any code that uses this FD
+    // directly.  This is safe because the CRT allocates FDs 0, 1 and
+    // 2 at startup even if they don't have valid underlying Windows
+    // handles.  This means we won't be overwriting an FD created by
+    // _open() after startup.
+    _dup2(_fileno(stdout), 1);
+  }
+  if (freopen("CONOUT$", "w", stderr)) {
     setvbuf(stderr, NULL, _IOLBF, kOutputBufferSize);
+    _dup2(_fileno(stderr), 2);
+  }
 
   // Fix all cout, wcout, cin, wcin, cerr, wcerr, clog and wclog.
   std::ios::sync_with_stdio();