Fix for leaking file descriptor issue

runtime/bin/process_macos.cc

 // Copyright (c) 2012, 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.
 
 #include "platform/globals.h"
 #if defined(TARGET_OS_MACOS)
 
 #include "bin/process.h"
 
 #include <errno.h>  // NOLINT
@@ skipping 514 matching lines @@
   VOID_TEMP_FAILURE_RETRY(close(exec_control[0]));
 
   // Return error code if any failures.
   if (bytes_read != 0) {
     VOID_TEMP_FAILURE_RETRY(close(read_in[0]));
     VOID_TEMP_FAILURE_RETRY(close(read_in[1]));
     VOID_TEMP_FAILURE_RETRY(close(read_err[0]));
     VOID_TEMP_FAILURE_RETRY(close(read_err[1]));
     VOID_TEMP_FAILURE_RETRY(close(write_out[0]));
     VOID_TEMP_FAILURE_RETRY(close(write_out[1]));
+
+    // Since exec() failed, we're not interested in the exit code.
+    // We close the reading side of the exit code pipe here.
+    // GetProcessExitCodes will get a broken pipe error when it tries to write
+    // to the writing side of the pipe and it will ignore the error.
+    VOID_TEMP_FAILURE_RETRY(close(*exit_event));
+    *exit_event = -1;
+
     if (bytes_read == -1) {
       return errno;  // Read failed.
     } else {
       return child_errno;  // Exec failed.
     }
   }
 
   FDUtils::SetNonBlocking(read_in[0]);
   *in = read_in[0];
   VOID_TEMP_FAILURE_RETRY(close(read_in[1]));
@@ skipping 20 matching lines @@
 
 
 intptr_t Process::CurrentProcessId() {
   return static_cast<intptr_t>(getpid());
 }
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_MACOS)