Fix double-close in EventConverterEvdevImpl

ui/events/ozone/evdev/scoped_input_device.cc

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "ui/events/ozone/evdev/scoped_input_device.h"
+
+#include <errno.h>
+#include <unistd.h>
+
+#include "base/debug/alias.h"
+#include "base/logging.h"
+#include "base/posix/eintr_wrapper.h"
+
+namespace ui {
+namespace internal {
+
+// static
+void ScopedInputDeviceCloseTraits::Free(int fd) {
+  // It's important to crash here.
+  // There are security implications to not closing a file descriptor
+  // properly. As file descriptors are "capabilities", keeping them open
+  // would make the current process keep access to a resource. Much of
+  // Chrome relies on being able to "drop" such access.
+  // It's especially problematic on Linux with the setuid sandbox, where
+  // a single open directory would bypass the entire security model.
+  int ret = IGNORE_EINTR(close(fd));
+
+  // TODO(davidben): Remove this once it's been determined whether
+  // https://crbug.com/603354 is caused by EBADF or a network filesystem
+  // returning some other error.
+  int close_errno = errno;
+  base::debug::Alias(&close_errno);

[davidben, 2017/01/18 19:48:10]

(Same comment as in the other CL that this base::debug::Alias isn't really
necessary with the modified PCHECK.)

[spang, 2017/01/18 20:40:35]

done.

+
+  PCHECK(0 == ret || close_errno != EBADF);
+}
+
+}  // namespace internal
+}  // namespace ui