common/test_utils.cc

//
// Copyright (C) 2012 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 "update_engine/common/test_utils.h"

#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <linux/loop.h>
#include <linux/major.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/ioctl.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <sys/sysmacros.h>
#include <sys/types.h>
#include <unistd.h>

#include <set>
#include <string>
#include <vector>

#include <base/files/file_util.h>
#include <base/logging.h>

#ifdef __ANDROID__
#include <libdm/loop_control.h>
#endif

#include "update_engine/common/error_code_utils.h"
#include "update_engine/common/utils.h"
#include "update_engine/payload_consumer/file_writer.h"

using std::set;
using std::string;
using std::vector;
using namespace std::chrono_literals;

namespace chromeos_update_engine {

void PrintTo(const Extent& extent, ::std::ostream* os) {
  *os << "(" << extent.start_block() << ", " << extent.num_blocks() << ")";
}

void PrintTo(const ErrorCode& error_code, ::std::ostream* os) {
  *os << utils::ErrorCodeToString(error_code);
}

namespace test_utils {

const uint8_t kRandomString[] = {
    0xf2, 0xb7, 0x55, 0x92, 0xea, 0xa6, 0xc9, 0x57, 0xe0, 0xf8, 0xeb, 0x34,
    0x93, 0xd9, 0xc4, 0x8f, 0xcb, 0x20, 0xfa, 0x37, 0x4b, 0x40, 0xcf, 0xdc,
    0xa5, 0x08, 0x70, 0x89, 0x79, 0x35, 0xe2, 0x3d, 0x56, 0xa4, 0x75, 0x73,
    0xa3, 0x6d, 0xd1, 0xd5, 0x26, 0xbb, 0x9c, 0x60, 0xbd, 0x2f, 0x5a, 0xfa,
    0xb7, 0xd4, 0x3a, 0x50, 0xa7, 0x6b, 0x3e, 0xfd, 0x61, 0x2b, 0x3a, 0x31,
    0x30, 0x13, 0x33, 0x53, 0xdb, 0xd0, 0x32, 0x71, 0x5c, 0x39, 0xed, 0xda,
    0xb4, 0x84, 0xca, 0xbc, 0xbd, 0x78, 0x1c, 0x0c, 0xd8, 0x0b, 0x41, 0xe8,
    0xe1, 0xe0, 0x41, 0xad, 0x03, 0x12, 0xd3, 0x3d, 0xb8, 0x75, 0x9b, 0xe6,
    0xd9, 0x01, 0xd0, 0x87, 0xf4, 0x36, 0xfa, 0xa7, 0x0a, 0xfa, 0xc5, 0x87,
    0x65, 0xab, 0x9a, 0x7b, 0xeb, 0x58, 0x23, 0xf0, 0xa8, 0x0a, 0xf2, 0x33,
    0x3a, 0xe2, 0xe3, 0x35, 0x74, 0x95, 0xdd, 0x3c, 0x59, 0x5a, 0xd9, 0x52,
    0x3a, 0x3c, 0xac, 0xe5, 0x15, 0x87, 0x6d, 0x82, 0xbc, 0xf8, 0x7d, 0xbe,
    0xca, 0xd3, 0x2c, 0xd6, 0xec, 0x38, 0xeb, 0xe4, 0x53, 0xb0, 0x4c, 0x3f,
    0x39, 0x29, 0xf7, 0xa4, 0x73, 0xa8, 0xcb, 0x32, 0x50, 0x05, 0x8c, 0x1c,
    0x1c, 0xca, 0xc9, 0x76, 0x0b, 0x8f, 0x6b, 0x57, 0x1f, 0x24, 0x2b, 0xba,
    0x82, 0xba, 0xed, 0x58, 0xd8, 0xbf, 0xec, 0x06, 0x64, 0x52, 0x6a, 0x3f,
    0xe4, 0xad, 0xce, 0x84, 0xb4, 0x27, 0x55, 0x14, 0xe3, 0x75, 0x59, 0x73,
    0x71, 0x51, 0xea, 0xe8, 0xcc, 0xda, 0x4f, 0x09, 0xaf, 0xa4, 0xbc, 0x0e,
    0xa6, 0x1f, 0xe2, 0x3a, 0xf8, 0x96, 0x7d, 0x30, 0x23, 0xc5, 0x12, 0xb5,
    0xd8, 0x73, 0x6b, 0x71, 0xab, 0xf1, 0xd7, 0x43, 0x58, 0xa7, 0xc9, 0xf0,
    0xe4, 0x85, 0x1c, 0xd6, 0x92, 0x50, 0x2c, 0x98, 0x36, 0xfe, 0x87, 0xaf,
    0x43, 0x8f, 0x8f, 0xf5, 0x88, 0x48, 0x18, 0x42, 0xcf, 0x42, 0xc1, 0xa8,
    0xe8, 0x05, 0x08, 0xa1, 0x45, 0x70, 0x5b, 0x8c, 0x39, 0x28, 0xab, 0xe9,
    0x6b, 0x51, 0xd2, 0xcb, 0x30, 0x04, 0xea, 0x7d, 0x2f, 0x6e, 0x6c, 0x3b,
    0x5f, 0x82, 0xd9, 0x5b, 0x89, 0x37, 0x65, 0x65, 0xbe, 0x9f, 0xa3, 0x5d,
};

string Readlink(const string& path) {
  vector<char> buf(PATH_MAX + 1);
  ssize_t r = readlink(path.c_str(), buf.data(), buf.size());
  if (r < 0)
    return "";
  CHECK_LT(r, static_cast<ssize_t>(buf.size()));
  return string(buf.begin(), buf.begin() + r);
}

bool WriteFileVector(const string& path, const brillo::Blob& data) {
  return utils::WriteFile(path.c_str(), data.data(), data.size());
}

bool WriteFileString(const string& path, const string& data) {
  return utils::WriteFile(path.c_str(), data.data(), data.size());
}

bool SetLoopDeviceStatus(int loop_device_fd,
                         const std::string& filename,
                         int loop_number,
                         bool writable) {
  struct loop_info64 device_info {};
  device_info.lo_offset = 0;
  device_info.lo_sizelimit = 0;  // 0 means whole file.
  device_info.lo_flags = (writable ? 0 : LO_FLAGS_READ_ONLY);
  device_info.lo_number = loop_number;
  strncpy(reinterpret_cast<char*>(device_info.lo_file_name),
          base::FilePath(filename).BaseName().value().c_str(),
          LO_NAME_SIZE - 1);
  device_info.lo_file_name[LO_NAME_SIZE - 1] = '\0';
  TEST_AND_RETURN_FALSE_ERRNO(
      ioctl(loop_device_fd, LOOP_SET_STATUS64, &device_info) == 0);
  if (writable) {
    // Make sure loop device isn't read only.
    int ro = 0;
    if (ioctl(loop_device_fd, BLKROSET, &ro) != 0) {
      PLOG(WARNING) << "Failed to mark loop device writable.";
    }
  }

  return true;
}

bool BindToUnusedLoopDeviceLegacy(int data_fd,
                                  const string& filename,
                                  bool writable,
                                  string* out_lo_dev_name) {
  // Get the next available loop-device.
  int control_fd =
      HANDLE_EINTR(open("/dev/loop-control", O_RDWR | O_LARGEFILE));
  TEST_AND_RETURN_FALSE_ERRNO(control_fd >= 0);
  int loop_number = ioctl(control_fd, LOOP_CTL_GET_FREE);
  IGNORE_EINTR(close(control_fd));
  *out_lo_dev_name = "/dev/loop" + std::to_string(loop_number);

  // Double check that the loop exists and is free.
  int loop_device_fd =
      HANDLE_EINTR(open(out_lo_dev_name->c_str(), O_RDWR | O_LARGEFILE));
  if (loop_device_fd == -1 && errno == ENOENT) {
    // Workaround the case when the loop device doesn't exist.
    TEST_AND_RETURN_FALSE_ERRNO(mknod(out_lo_dev_name->c_str(),
                                      S_IFBLK | 0660,
                                      makedev(LOOP_MAJOR, loop_number)) == 0);
    loop_device_fd =
        HANDLE_EINTR(open(out_lo_dev_name->c_str(), O_RDWR | O_LARGEFILE));
  }
  TEST_AND_RETURN_FALSE_ERRNO(loop_device_fd != -1);
  ScopedFdCloser loop_device_fd_closer(&loop_device_fd);

  struct loop_info64 device_info;
  if (ioctl(loop_device_fd, LOOP_GET_STATUS64, &device_info) != -1 ||
      errno != ENXIO) {
    PLOG(ERROR) << "Loop device " << out_lo_dev_name->c_str()
                << " already in use";
    return false;
  }

  // Assign the data fd to the loop device.
  TEST_AND_RETURN_FALSE_ERRNO(ioctl(loop_device_fd, LOOP_SET_FD, data_fd) == 0);
  return SetLoopDeviceStatus(loop_device_fd, filename, loop_number, writable);
}

bool BindToUnusedLoopDevice(const string& filename,
                            bool writable,
                            string* out_lo_dev_name) {
  CHECK(out_lo_dev_name);
  int data_fd = open(filename.c_str(),
                     (writable ? O_RDWR : O_RDONLY) | O_LARGEFILE | O_CLOEXEC);
  TEST_AND_RETURN_FALSE_ERRNO(data_fd >= 0);
  ScopedFdCloser data_fd_closer(&data_fd);

#ifdef __ANDROID__
  // Use libdm to bind a free loop device. The library internally handles the
  // race condition.
  android::dm::LoopControl loop_control;
  TEST_AND_RETURN_FALSE(loop_control.Attach(data_fd, 5s, out_lo_dev_name));
  int loop_device_fd = open(out_lo_dev_name->c_str(), O_RDWR | O_CLOEXEC);
  ScopedFdCloser loop_fd_closer(&loop_device_fd);
  int loop_number;
  TEST_AND_RETURN_FALSE(
      sscanf(out_lo_dev_name->c_str(), "/dev/block/loop%d", &loop_number) == 1);
  return SetLoopDeviceStatus(loop_device_fd, filename, loop_number, writable);
#else
  return BindToUnusedLoopDeviceLegacy(
      data_fd, filename, writable, out_lo_dev_name);
#endif
}

bool UnbindLoopDevice(const string& lo_dev_name) {
  int loop_device_fd =
      HANDLE_EINTR(open(lo_dev_name.c_str(), O_RDWR | O_LARGEFILE));
  if (loop_device_fd == -1 && errno == ENOENT)
    return true;
  TEST_AND_RETURN_FALSE_ERRNO(loop_device_fd != -1);
  ScopedFdCloser loop_device_fd_closer(&loop_device_fd);

  struct loop_info64 device_info;
  // Check if the device is bound before trying to unbind it.
  int get_stat_err = ioctl(loop_device_fd, LOOP_GET_STATUS64, &device_info);
  if (get_stat_err == -1 && errno == ENXIO)
    return true;

  TEST_AND_RETURN_FALSE_ERRNO(ioctl(loop_device_fd, LOOP_CLR_FD) == 0);
  return true;
}

bool ExpectVectorsEq(const brillo::Blob& expected, const brillo::Blob& actual) {
  EXPECT_EQ(expected.size(), actual.size());
  if (expected.size() != actual.size())
    return false;
  bool is_all_eq = true;
  for (unsigned int i = 0; i < expected.size(); i++) {
    EXPECT_EQ(expected[i], actual[i]) << "offset: " << i;
    is_all_eq = is_all_eq && (expected[i] == actual[i]);
  }
  return is_all_eq;
}

void FillWithData(brillo::Blob* buffer) {
  size_t input_counter = 0;
  for (uint8_t& b : *buffer) {
    b = kRandomString[input_counter];
    input_counter++;
    input_counter %= sizeof(kRandomString);
  }
}

ScopedLoopMounter::ScopedLoopMounter(const string& file_path,
                                     string* mnt_path,
                                     unsigned long flags) {  // NOLINT - long
  EXPECT_TRUE(temp_dir_.CreateUniqueTempDir());
  *mnt_path = temp_dir_.GetPath().value();

  string loop_dev;
  loop_binder_.reset(
      new ScopedLoopbackDeviceBinder(file_path, true, &loop_dev));

  EXPECT_TRUE(utils::MountFilesystem(loop_dev, *mnt_path, flags, "", ""));
  unmounter_.reset(new ScopedFilesystemUnmounter(*mnt_path));
}

base::FilePath GetBuildArtifactsPath() {
  base::FilePath exe_path;
  base::ReadSymbolicLink(base::FilePath("/proc/self/exe"), &exe_path);
  return exe_path.DirName();
}

string GetBuildArtifactsPath(const string& relative_path) {
  return GetBuildArtifactsPath().Append(relative_path).value();
}

}  // namespace test_utils
}  // namespace chromeos_update_engine