payload_generator/block_mapping_unittest.cc

// Copyright 2015 The Chromium OS 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 "update_engine/payload_generator/block_mapping.h"

#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.h>

#include <string>
#include <vector>

#include <gtest/gtest.h>

#include "update_engine/test_utils.h"
#include "update_engine/utils.h"

using std::string;
using std::vector;

namespace chromeos_update_engine {

namespace {

}  // namespace

class BlockMappingTest : public ::testing::Test {
 protected:
  void SetUp() override {
    EXPECT_TRUE(utils::MakeTempFile("BlockMappingTest_old.XXXXXX",
                                    &old_part_path_,
                                    nullptr));
    EXPECT_TRUE(utils::MakeTempFile("BlockMappingTest_new.XXXXXX",
                                    &new_part_path_,
                                    nullptr));

    old_part_unlinker_.reset(new ScopedPathUnlinker(old_part_path_));
    new_part_unlinker_.reset(new ScopedPathUnlinker(new_part_path_));
  }

  // Old new partition files used in testing.
  string old_part_path_;
  string new_part_path_;
  std::unique_ptr<ScopedPathUnlinker> old_part_unlinker_;
  std::unique_ptr<ScopedPathUnlinker> new_part_unlinker_;

  size_t block_size_{1024};
  BlockMapping bm_{block_size_};  // BlockMapping under test.
};

TEST_F(BlockMappingTest, FirstAddedBlockIsZero) {
  chromeos::Blob blob(block_size_);
  // The BlockMapping just assigns the block ids in order, so it doesn't matter
  // what are the contents of the first block.
  blob[0] = 42;
  EXPECT_EQ(0, bm_.AddBlock(blob));
  blob[0] = 5;
  EXPECT_EQ(1, bm_.AddBlock(blob));
}

TEST_F(BlockMappingTest, BlocksAreNotKeptInMemory) {
  test_utils::WriteFileString(old_part_path_, string(block_size_, 'a'));
  int old_fd = HANDLE_EINTR(open(old_part_path_.c_str(), O_RDONLY));
  ScopedFdCloser old_fd_closer(&old_fd);

  EXPECT_EQ(0, bm_.AddDiskBlock(old_fd, 0));

  // Check that the block_data is not stored on memory if we just used the block
  // once.
  for (const auto& it : bm_.mapping_) {
    for (const BlockMapping::UniqueBlock& ublock : it.second) {
      EXPECT_TRUE(ublock.block_data.empty());
    }
  }

  chromeos::Blob block(block_size_, 'a');
  for (int i = 0; i < 5; ++i) {
    // Re-add the same block 5 times.
    EXPECT_EQ(0, bm_.AddBlock(block));
  }

  for (const auto& it : bm_.mapping_) {
    for (const BlockMapping::UniqueBlock& ublock : it.second) {
      EXPECT_FALSE(ublock.block_data.empty());
      // The block was loaded from disk only 4 times, and after that the counter
      // is not updated anymore.
      EXPECT_EQ(4, ublock.times_read);
    }
  }
}

TEST_F(BlockMappingTest, MapPartitionBlocks) {
  // A string with 10 blocks where all the blocks are different.
  string old_contents(10 * block_size_, '\0');
  for (size_t i = 0; i < old_contents.size(); ++i)
    old_contents[i] = 4 + i / block_size_;
  test_utils::WriteFileString(old_part_path_, old_contents);

  // A string including the block with all zeros and overlapping some of the
  // other blocks in old_contents.
  string new_contents(6 * block_size_, '\0');
  for (size_t i = 0; i < new_contents.size(); ++i)
    new_contents[i] = i / block_size_;
  test_utils::WriteFileString(new_part_path_, new_contents);

  vector<BlockMapping::BlockId> old_ids, new_ids;
  EXPECT_TRUE(MapPartitionBlocks(old_part_path_,
                                 new_part_path_,
                                 old_contents.size(),
                                 new_contents.size(),
                                 block_size_,
                                 &old_ids,
                                 &new_ids));

  EXPECT_EQ((vector<BlockMapping::BlockId>{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}),
            old_ids);
  EXPECT_EQ((vector<BlockMapping::BlockId>{0, 11, 12, 13, 1, 2}),
            new_ids);
}

}  // namespace chromeos_update_engine