src/tracing/ipc/posix_shared_memory_unittest.cc

/*
 * Copyright (C) 2017 The Android Open Source Project
 *
 * 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 "src/tracing/ipc/posix_shared_memory.h"

#if PERFETTO_BUILDFLAG(PERFETTO_OS_LINUX) ||   \
    PERFETTO_BUILDFLAG(PERFETTO_OS_ANDROID) || \
    PERFETTO_BUILDFLAG(PERFETTO_OS_APPLE)

#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <sys/stat.h>
#include <unistd.h>

#include "perfetto/base/build_config.h"
#include "perfetto/ext/base/file_utils.h"
#include "perfetto/ext/base/scoped_file.h"
#include "perfetto/ext/base/temp_file.h"
#include "perfetto/ext/base/utils.h"
#include "src/base/test/test_task_runner.h"
#include "src/base/test/vm_test_utils.h"
#include "src/tracing/ipc/memfd.h"
#include "test/gtest_and_gmock.h"

namespace perfetto {
namespace {

bool IsFileDescriptorClosed(int fd) {
  return lseek(fd, 0, SEEK_CUR) == -1 && errno == EBADF;
}

TEST(PosixSharedMemoryTest, DestructorUnmapsMemory) {
  PosixSharedMemory::Factory factory;
  std::unique_ptr<SharedMemory> shm =
      factory.CreateSharedMemory(base::GetSysPageSize());
  ASSERT_NE(shm.get(), nullptr);
  void* const shm_start = shm->start();
  const size_t shm_size = shm->size();
  ASSERT_NE(nullptr, shm_start);
  ASSERT_EQ(base::GetSysPageSize(), shm_size);

  memcpy(shm_start, "test", 5);
  ASSERT_TRUE(base::vm_test_utils::IsMapped(shm_start, shm_size));

  shm.reset();
  ASSERT_FALSE(base::vm_test_utils::IsMapped(shm_start, shm_size));
}

TEST(PosixSharedMemoryTest, DestructorClosesFD) {
  std::unique_ptr<PosixSharedMemory> shm =
      PosixSharedMemory::Create(base::GetSysPageSize());
  ASSERT_NE(shm.get(), nullptr);
  int fd = shm->fd();
  ASSERT_GE(fd, 0);
  ASSERT_EQ(static_cast<off_t>(base::GetSysPageSize()), lseek(fd, 0, SEEK_END));

  shm.reset();
  ASSERT_TRUE(IsFileDescriptorClosed(fd));
}

TEST(PosixSharedMemoryTest, AttachToFdWithoutSeals) {
  base::TempFile tmp_file = base::TempFile::CreateUnlinked();
  const int fd_num = tmp_file.fd();
  ASSERT_EQ(0, ftruncate(fd_num, static_cast<off_t>(base::GetSysPageSize())));
  ASSERT_EQ(7, base::WriteAll(fd_num, "foobar", 7));

  std::unique_ptr<PosixSharedMemory> shm = PosixSharedMemory::AttachToFd(
      tmp_file.ReleaseFD(), /*require_seals_if_supported=*/false);
  ASSERT_NE(shm.get(), nullptr);
  void* const shm_start = shm->start();
  const size_t shm_size = shm->size();
  ASSERT_NE(nullptr, shm_start);
  ASSERT_EQ(base::GetSysPageSize(), shm_size);
  ASSERT_EQ(0, memcmp("foobar", shm_start, 7));

  ASSERT_FALSE(IsFileDescriptorClosed(fd_num));

  shm.reset();
  ASSERT_TRUE(IsFileDescriptorClosed(fd_num));
  ASSERT_FALSE(base::vm_test_utils::IsMapped(shm_start, shm_size));
}

TEST(PosixSharedMemoryTest, AttachToFdRequiresSeals) {
  base::TempFile tmp_file = base::TempFile::CreateUnlinked();
  const int fd_num = tmp_file.fd();
  ASSERT_EQ(0, ftruncate(fd_num, static_cast<off_t>(base::GetSysPageSize())));

  std::unique_ptr<PosixSharedMemory> shm =
      PosixSharedMemory::AttachToFd(tmp_file.ReleaseFD());

  if (HasMemfdSupport()) {
    EXPECT_EQ(shm.get(), nullptr);
  } else {
    ASSERT_NE(shm.get(), nullptr);
    EXPECT_NE(shm->start(), nullptr);
  }
}

TEST(PosixSharedMemoryTest, CreateAndMap) {
  // Deliberately trying to cover cases where the shm size is smaller than the
  // system page size (crbug.com/1116576).
  const size_t kLessThanAPage = 2048;
  std::unique_ptr<PosixSharedMemory> shm =
      PosixSharedMemory::Create(kLessThanAPage);
  void* const shm_start = shm->start();
  const size_t shm_size = shm->size();
  ASSERT_NE(shm_start, nullptr);
  ASSERT_EQ(shm_size, kLessThanAPage);

  memcpy(shm_start, "test", 5);
  ASSERT_TRUE(base::vm_test_utils::IsMapped(shm_start, shm_size));

  base::ScopedFile shm_fd2(dup(shm->fd()));
  std::unique_ptr<PosixSharedMemory> shm2 =
      PosixSharedMemory::AttachToFd(std::move(shm_fd2));
  ASSERT_NE(shm2.get(), nullptr);
  void* const shm2_start = shm2->start();
  const size_t shm2_size = shm2->size();
  ASSERT_NE(shm2_start, nullptr);
  ASSERT_EQ(shm2_size, shm_size);

  ASSERT_EQ(0, memcmp("test", shm2->start(), 5));
  ASSERT_TRUE(base::vm_test_utils::IsMapped(shm2_start, shm2_size));

  shm2.reset();
  ASSERT_FALSE(base::vm_test_utils::IsMapped(shm2_start, shm2_size));
  ASSERT_TRUE(base::vm_test_utils::IsMapped(shm_start, shm_size));

  shm.reset();
  ASSERT_FALSE(base::vm_test_utils::IsMapped(shm2_start, shm2_size));
  ASSERT_FALSE(base::vm_test_utils::IsMapped(shm_start, shm_size));
}

}  // namespace
}  // namespace perfetto
#endif  // OS_LINUX || OS_ANDROID || OS_APPLE