Update from https://crrev.com/306655

sandbox/linux/services/proc_util_unittest.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/services/proc_util.h"
+
+#include <fcntl.h>
+#include <unistd.h>
+
+#include "base/files/scoped_file.h"
+#include "base/posix/eintr_wrapper.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace sandbox {
+
+TEST(ProcUtil, CountOpenFds) {
+  base::ScopedFD proc_fd(open("/proc", O_RDONLY | O_DIRECTORY));
+  ASSERT_TRUE(proc_fd.is_valid());
+  int fd_count = ProcUtil::CountOpenFds(proc_fd.get());
+  int fd = open("/dev/null", O_RDONLY);
+  ASSERT_LE(0, fd);
+  EXPECT_EQ(fd_count + 1, ProcUtil::CountOpenFds(proc_fd.get()));
+  ASSERT_EQ(0, IGNORE_EINTR(close(fd)));
+  EXPECT_EQ(fd_count, ProcUtil::CountOpenFds(proc_fd.get()));
+}
+
+TEST(ProcUtil, HasOpenDirectory) {
+  // No open directory should exist at startup.
+  EXPECT_FALSE(ProcUtil::HasOpenDirectory(-1));
+  {
+    // Have a "/dev" file descriptor around.
+    int dev_fd = open("/dev", O_RDONLY | O_DIRECTORY);
+    base::ScopedFD dev_fd_closer(dev_fd);
+    EXPECT_TRUE(ProcUtil::HasOpenDirectory(-1));
+  }
+  EXPECT_FALSE(ProcUtil::HasOpenDirectory(-1));
+}
+
+TEST(ProcUtil, HasOpenDirectoryWithFD) {
+  int proc_fd = open("/proc", O_RDONLY | O_DIRECTORY);
+  base::ScopedFD proc_fd_closer(proc_fd);
+  ASSERT_LE(0, proc_fd);
+
+  // Don't pass |proc_fd|, an open directory (proc_fd) should
+  // be detected.
+  EXPECT_TRUE(ProcUtil::HasOpenDirectory(-1));
+  // Pass |proc_fd| and no open directory should be detected.
+  EXPECT_FALSE(ProcUtil::HasOpenDirectory(proc_fd));
+
+  {
+    // Have a "/dev" file descriptor around.
+    int dev_fd = open("/dev", O_RDONLY | O_DIRECTORY);
+    base::ScopedFD dev_fd_closer(dev_fd);
+    EXPECT_TRUE(ProcUtil::HasOpenDirectory(proc_fd));
+  }
+
+  // The "/dev" file descriptor should now be closed, |proc_fd| is the only
+  // directory file descriptor open.
+  EXPECT_FALSE(ProcUtil::HasOpenDirectory(proc_fd));
+}
+
+}  // namespace sandbox