Linux sandbox: add test to ensure that pread64 can be forwarded.

sandbox/linux/tests/scoped_temporary_file.cc

+// Copyright 2014 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 "sandbox/linux/tests/scoped_temporary_file.h"
+
+#include <stdlib.h>
+#include <unistd.h>
+
+#include "base/logging.h"
+#include "base/macros.h"
+#include "base/posix/eintr_wrapper.h"
+#include "build/build_config.h"
+
+namespace sandbox {
+
+ScopedTemporaryFile::ScopedTemporaryFile() : fd_(-1) {
+#if defined(OS_ANDROID)
+  static const char file_template[] = "/data/local/tmp/ScopedTempFileXXXXXX";
+#else
+  static const char file_template[] = "/tmp/ScopedTempFileXXXXXX";
+#endif  // defined(OS_ANDROID)
+  COMPILE_ASSERT(sizeof(full_file_name_) >= sizeof(file_template),
+                 full_file_name_is_large_enough);
+  memcpy(full_file_name_, file_template, sizeof(file_template));
+  fd_ = mkstemp(full_file_name_);
+  CHECK_LE(0, fd_);
+}
+
+ScopedTemporaryFile::~ScopedTemporaryFile() {
+  CHECK_EQ(0, unlink(full_file_name_));
+  CHECK_EQ(0, IGNORE_EINTR(close(fd_)));
+}
+
+}  // namespace sandbox