// Copyright 2021 The gVisor Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include <fcntl.h>
#include <stdlib.h>
#include <sys/mount.h>
#include <unistd.h>

#include <memory>
#include <string>
#include <vector>

#include "gtest/gtest.h"
#include "benchmark/benchmark.h"
#include "test/util/capability_util.h"
#include "test/util/fs_util.h"
#include "test/util/logging.h"
#include "test/util/temp_path.h"
#include "test/util/test_util.h"
#include "test/util/verity_util.h"

namespace gvisor {
namespace testing {

namespace {

void BM_VerityRead(benchmark::State& state) {
  const int size = state.range(0);
  const std::string contents(size, 0);

  // Mount a tmpfs file system to be wrapped by a verity fs.
  TempPath dir = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDir());
  TEST_CHECK(mount("", dir.path().c_str(), "tmpfs", 0, "") == 0);

  auto path = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFileWith(
      dir.path(), contents, TempPath::kDefaultFileMode));
  std::string filename = std::string(Basename(path.path()));

  std::string verity_dir = TEST_CHECK_NO_ERRNO_AND_VALUE(
      MountVerity(dir.path(), {EnableTarget(filename, O_RDONLY)}));

  FileDescriptor fd =
      ASSERT_NO_ERRNO_AND_VALUE(Open(JoinPath(verity_dir, filename), O_RDONLY));
  std::vector<char> buf(size);
  for (auto _ : state) {
    TEST_CHECK(PreadFd(fd.get(), buf.data(), buf.size(), 0) == size);
  }

  state.SetBytesProcessed(static_cast<int64_t>(size) *
                          static_cast<int64_t>(state.iterations()));
}

BENCHMARK(BM_VerityRead)->Range(1, 1 << 26)->UseRealTime();

}  // namespace

}  // namespace testing
}  // namespace gvisor