platform_bootable_recovery/install.cpp

/*
 * Copyright (C) 2007 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 "install.h"

#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <inttypes.h>
#include <limits.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <unistd.h>

#include <algorithm>
#include <atomic>
#include <chrono>
#include <condition_variable>
#include <functional>
#include <limits>
#include <mutex>
#include <thread>
#include <vector>

#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/parsedouble.h>
#include <android-base/parseint.h>
#include <android-base/properties.h>
#include <android-base/stringprintf.h>
#include <android-base/strings.h>
#include <android-base/unique_fd.h>
#include <vintf/VintfObjectRecovery.h>

#include "common.h"
#include "otautil/error_code.h"
#include "otautil/paths.h"
#include "otautil/sysutil.h"
#include "otautil/thermalutil.h"
#include "private/install.h"
#include "roots.h"
#include "ui.h"
#include "verifier.h"

using namespace std::chrono_literals;

// Default allocation of progress bar segments to operations
static constexpr int VERIFICATION_PROGRESS_TIME = 60;
static constexpr float VERIFICATION_PROGRESS_FRACTION = 0.25;

static std::condition_variable finish_log_temperature;

bool ReadMetadataFromPackage(ZipArchiveHandle zip, std::map<std::string, std::string>* metadata) {
  CHECK(metadata != nullptr);

  static constexpr const char* METADATA_PATH = "META-INF/com/android/metadata";
  ZipString path(METADATA_PATH);
  ZipEntry entry;
  if (FindEntry(zip, path, &entry) != 0) {
    LOG(ERROR) << "Failed to find " << METADATA_PATH;
    return false;
  }

  uint32_t length = entry.uncompressed_length;
  std::string metadata_string(length, '\0');
  int32_t err =
      ExtractToMemory(zip, &entry, reinterpret_cast<uint8_t*>(&metadata_string[0]), length);
  if (err != 0) {
    LOG(ERROR) << "Failed to extract " << METADATA_PATH << ": " << ErrorCodeString(err);
    return false;
  }

  for (const std::string& line : android::base::Split(metadata_string, "\n")) {
    size_t eq = line.find('=');
    if (eq != std::string::npos) {
      metadata->emplace(android::base::Trim(line.substr(0, eq)),
                        android::base::Trim(line.substr(eq + 1)));
    }
  }

  return true;
}

// Gets the value for the given key in |metadata|. Returns an emtpy string if the key isn't
// present.
static std::string get_value(const std::map<std::string, std::string>& metadata,
                             const std::string& key) {
  const auto& it = metadata.find(key);
  return (it == metadata.end()) ? "" : it->second;
}

static std::string OtaTypeToString(OtaType type) {
  switch (type) {
    case OtaType::AB:
      return "AB";
    case OtaType::BLOCK:
      return "BLOCK";
    case OtaType::BRICK:
      return "BRICK";
  }
}

// Read the build.version.incremental of src/tgt from the metadata and log it to last_install.
static void ReadSourceTargetBuild(const std::map<std::string, std::string>& metadata,
                                  std::vector<std::string>* log_buffer) {
  // Examples of the pre-build and post-build strings in metadata:
  //   pre-build-incremental=2943039
  //   post-build-incremental=2951741
  auto source_build = get_value(metadata, "pre-build-incremental");
  if (!source_build.empty()) {
    log_buffer->push_back("source_build: " + source_build);
  }

  auto target_build = get_value(metadata, "post-build-incremental");
  if (!target_build.empty()) {
    log_buffer->push_back("target_build: " + target_build);
  }
}

// Checks the build version, fingerprint and timestamp in the metadata of the A/B package.
// Downgrading is not allowed unless explicitly enabled in the package and only for
// incremental packages.
static int CheckAbSpecificMetadata(const std::map<std::string, std::string>& metadata) {
  // Incremental updates should match the current build.
  auto device_pre_build = android::base::GetProperty("ro.build.version.incremental", "");
  auto pkg_pre_build = get_value(metadata, "pre-build-incremental");
  if (!pkg_pre_build.empty() && pkg_pre_build != device_pre_build) {
    LOG(ERROR) << "Package is for source build " << pkg_pre_build << " but expected "
               << device_pre_build;
    return INSTALL_ERROR;
  }

  auto device_fingerprint = android::base::GetProperty("ro.build.fingerprint", "");
  auto pkg_pre_build_fingerprint = get_value(metadata, "pre-build");
  if (!pkg_pre_build_fingerprint.empty() && pkg_pre_build_fingerprint != device_fingerprint) {
    LOG(ERROR) << "Package is for source build " << pkg_pre_build_fingerprint << " but expected "
               << device_fingerprint;
    return INSTALL_ERROR;
  }

  // Check for downgrade version.
  int64_t build_timestamp =
      android::base::GetIntProperty("ro.build.date.utc", std::numeric_limits<int64_t>::max());
  int64_t pkg_post_timestamp = 0;
  // We allow to full update to the same version we are running, in case there
  // is a problem with the current copy of that version.
  auto pkg_post_timestamp_string = get_value(metadata, "post-timestamp");
  if (pkg_post_timestamp_string.empty() ||
      !android::base::ParseInt(pkg_post_timestamp_string, &pkg_post_timestamp) ||
      pkg_post_timestamp < build_timestamp) {
    if (get_value(metadata, "ota-downgrade") != "yes") {
      LOG(ERROR) << "Update package is older than the current build, expected a build "
                    "newer than timestamp "
                 << build_timestamp << " but package has timestamp " << pkg_post_timestamp
                 << " and downgrade not allowed.";
      return INSTALL_ERROR;
    }
    if (pkg_pre_build_fingerprint.empty()) {
      LOG(ERROR) << "Downgrade package must have a pre-build version set, not allowed.";
      return INSTALL_ERROR;
    }
  }

  return 0;
}

int CheckPackageMetadata(const std::map<std::string, std::string>& metadata, OtaType ota_type) {
  auto package_ota_type = get_value(metadata, "ota-type");
  auto expected_ota_type = OtaTypeToString(ota_type);
  if (ota_type != OtaType::AB && ota_type != OtaType::BRICK) {
    LOG(INFO) << "Skip package metadata check for ota type " << expected_ota_type;
    return 0;
  }

  if (package_ota_type != expected_ota_type) {
    LOG(ERROR) << "Unexpected ota package type, expects " << expected_ota_type << ", actual "
               << package_ota_type;
    return INSTALL_ERROR;
  }

  auto device = android::base::GetProperty("ro.product.device", "");
  auto pkg_device = get_value(metadata, "pre-device");
  if (pkg_device != device || pkg_device.empty()) {
    LOG(ERROR) << "Package is for product " << pkg_device << " but expected " << device;
    return INSTALL_ERROR;
  }

  // We allow the package to not have any serialno; and we also allow it to carry multiple serial
  // numbers split by "|"; e.g. serialno=serialno1|serialno2|serialno3 ... We will fail the
  // verification if the device's serialno doesn't match any of these carried numbers.
  auto pkg_serial_no = get_value(metadata, "serialno");
  if (!pkg_serial_no.empty()) {
    auto device_serial_no = android::base::GetProperty("ro.serialno", "");
    bool serial_number_match = false;
    for (const auto& number : android::base::Split(pkg_serial_no, "|")) {
      if (device_serial_no == android::base::Trim(number)) {
        serial_number_match = true;
      }
    }
    if (!serial_number_match) {
      LOG(ERROR) << "Package is for serial " << pkg_serial_no;
      return INSTALL_ERROR;
    }
  }

  if (ota_type == OtaType::AB) {
    return CheckAbSpecificMetadata(metadata);
  }

  return 0;
}

int SetUpAbUpdateCommands(const std::string& package, ZipArchiveHandle zip, int status_fd,
                          std::vector<std::string>* cmd) {
  CHECK(cmd != nullptr);

  // For A/B updates we extract the payload properties to a buffer and obtain the RAW payload offset
  // in the zip file.
  static constexpr const char* AB_OTA_PAYLOAD_PROPERTIES = "payload_properties.txt";
  ZipString property_name(AB_OTA_PAYLOAD_PROPERTIES);
  ZipEntry properties_entry;
  if (FindEntry(zip, property_name, &properties_entry) != 0) {
    LOG(ERROR) << "Failed to find " << AB_OTA_PAYLOAD_PROPERTIES;
    return INSTALL_CORRUPT;
  }
  uint32_t properties_entry_length = properties_entry.uncompressed_length;
  std::vector<uint8_t> payload_properties(properties_entry_length);
  int32_t err =
      ExtractToMemory(zip, &properties_entry, payload_properties.data(), properties_entry_length);
  if (err != 0) {
    LOG(ERROR) << "Failed to extract " << AB_OTA_PAYLOAD_PROPERTIES << ": " << ErrorCodeString(err);
    return INSTALL_CORRUPT;
  }

  static constexpr const char* AB_OTA_PAYLOAD = "payload.bin";
  ZipString payload_name(AB_OTA_PAYLOAD);
  ZipEntry payload_entry;
  if (FindEntry(zip, payload_name, &payload_entry) != 0) {
    LOG(ERROR) << "Failed to find " << AB_OTA_PAYLOAD;
    return INSTALL_CORRUPT;
  }
  long payload_offset = payload_entry.offset;
  *cmd = {
    "/system/bin/update_engine_sideload",
    "--payload=file://" + package,
    android::base::StringPrintf("--offset=%ld", payload_offset),
    "--headers=" + std::string(payload_properties.begin(), payload_properties.end()),
    android::base::StringPrintf("--status_fd=%d", status_fd),
  };
  return 0;
}

int SetUpNonAbUpdateCommands(const std::string& package, ZipArchiveHandle zip, int retry_count,
                             int status_fd, std::vector<std::string>* cmd) {
  CHECK(cmd != nullptr);

  // In non-A/B updates we extract the update binary from the package.
  static constexpr const char* UPDATE_BINARY_NAME = "META-INF/com/google/android/update-binary";
  ZipString binary_name(UPDATE_BINARY_NAME);
  ZipEntry binary_entry;
  if (FindEntry(zip, binary_name, &binary_entry) != 0) {
    LOG(ERROR) << "Failed to find update binary " << UPDATE_BINARY_NAME;
    return INSTALL_CORRUPT;
  }

  const std::string binary_path = Paths::Get().temporary_update_binary();
  unlink(binary_path.c_str());
  android::base::unique_fd fd(
      open(binary_path.c_str(), O_CREAT | O_WRONLY | O_TRUNC | O_CLOEXEC, 0755));
  if (fd == -1) {
    PLOG(ERROR) << "Failed to create " << binary_path;
    return INSTALL_ERROR;
  }

  int32_t error = ExtractEntryToFile(zip, &binary_entry, fd);
  if (error != 0) {
    LOG(ERROR) << "Failed to extract " << UPDATE_BINARY_NAME << ": " << ErrorCodeString(error);
    return INSTALL_ERROR;
  }

  // When executing the update binary contained in the package, the arguments passed are:
  //   - the version number for this interface
  //   - an FD to which the program can write in order to update the progress bar.
  //   - the name of the package zip file.
  //   - an optional argument "retry" if this update is a retry of a failed update attempt.
  *cmd = {
    binary_path,
    std::to_string(kRecoveryApiVersion),
    std::to_string(status_fd),
    package,
  };
  if (retry_count > 0) {
    cmd->push_back("retry");
  }
  return 0;
}

static void log_max_temperature(int* max_temperature, const std::atomic<bool>& logger_finished) {
  CHECK(max_temperature != nullptr);
  std::mutex mtx;
  std::unique_lock<std::mutex> lck(mtx);
  while (!logger_finished.load() &&
         finish_log_temperature.wait_for(lck, 20s) == std::cv_status::timeout) {
    *max_temperature = std::max(*max_temperature, GetMaxValueFromThermalZone());
  }
}

// If the package contains an update binary, extract it and run it.
static int try_update_binary(const std::string& package, ZipArchiveHandle zip, bool* wipe_cache,
                             std::vector<std::string>* log_buffer, int retry_count,
                             int* max_temperature) {
  std::map<std::string, std::string> metadata;
  if (!ReadMetadataFromPackage(zip, &metadata)) {
    LOG(ERROR) << "Failed to parse metadata in the zip file";
    return INSTALL_CORRUPT;
  }

  bool is_ab = android::base::GetBoolProperty("ro.build.ab_update", false);
  // Verifies against the metadata in the package first.
  if (int check_status = is_ab ? CheckPackageMetadata(metadata, OtaType::AB) : 0;
      check_status != 0) {
    log_buffer->push_back(android::base::StringPrintf("error: %d", kUpdateBinaryCommandFailure));
    return check_status;
  }

  ReadSourceTargetBuild(metadata, log_buffer);

  // The updater in child process writes to the pipe to communicate with recovery.
  android::base::unique_fd pipe_read, pipe_write;
  if (!android::base::Pipe(&pipe_read, &pipe_write)) {
    PLOG(ERROR) << "Failed to create pipe for updater-recovery communication";
    return INSTALL_CORRUPT;
  }

  // The updater-recovery communication protocol.
  //
  //   progress <frac> <secs>
  //       fill up the next <frac> part of of the progress bar over <secs> seconds. If <secs> is
  //       zero, use `set_progress` commands to manually control the progress of this segment of the
  //       bar.
  //
  //   set_progress <frac>
  //       <frac> should be between 0.0 and 1.0; sets the progress bar within the segment defined by
  //       the most recent progress command.
  //
  //   ui_print <string>
  //       display <string> on the screen.
  //
  //   wipe_cache
  //       a wipe of cache will be performed following a successful installation.
  //
  //   clear_display
  //       turn off the text display.
  //
  //   enable_reboot
  //       packages can explicitly request that they want the user to be able to reboot during
  //       installation (useful for debugging packages that don't exit).
  //
  //   retry_update
  //       updater encounters some issue during the update. It requests a reboot to retry the same
  //       package automatically.
  //
  //   log <string>
  //       updater requests logging the string (e.g. cause of the failure).
  //

  std::vector<std::string> args;
  if (int update_status =
          is_ab ? SetUpAbUpdateCommands(package, zip, pipe_write.get(), &args)
                : SetUpNonAbUpdateCommands(package, zip, retry_count, pipe_write.get(), &args);
      update_status != 0) {
    log_buffer->push_back(android::base::StringPrintf("error: %d", kUpdateBinaryCommandFailure));
    return update_status;
  }

  pid_t pid = fork();
  if (pid == -1) {
    PLOG(ERROR) << "Failed to fork update binary";
    log_buffer->push_back(android::base::StringPrintf("error: %d", kForkUpdateBinaryFailure));
    return INSTALL_ERROR;
  }

  if (pid == 0) {
    umask(022);
    pipe_read.reset();

    // Convert the std::string vector to a NULL-terminated char* vector suitable for execv.
    auto chr_args = StringVectorToNullTerminatedArray(args);
    execv(chr_args[0], chr_args.data());
    // We shouldn't use LOG/PLOG in the forked process, since they may cause the child process to
    // hang. This deadlock results from an improperly copied mutex in the ui functions.
    // (Bug: 34769056)
    fprintf(stdout, "E:Can't run %s (%s)\n", chr_args[0], strerror(errno));
    _exit(EXIT_FAILURE);
  }
  pipe_write.reset();

  std::atomic<bool> logger_finished(false);
  std::thread temperature_logger(log_max_temperature, max_temperature, std::ref(logger_finished));

  *wipe_cache = false;
  bool retry_update = false;

  char buffer[1024];
  FILE* from_child = android::base::Fdopen(std::move(pipe_read), "r");
  while (fgets(buffer, sizeof(buffer), from_child) != nullptr) {
    std::string line(buffer);
    size_t space = line.find_first_of(" \n");
    std::string command(line.substr(0, space));
    if (command.empty()) continue;

    // Get rid of the leading and trailing space and/or newline.
    std::string args = space == std::string::npos ? "" : android::base::Trim(line.substr(space));

    if (command == "progress") {
      std::vector<std::string> tokens = android::base::Split(args, " ");
      double fraction;
      int seconds;
      if (tokens.size() == 2 && android::base::ParseDouble(tokens[0].c_str(), &fraction) &&
          android::base::ParseInt(tokens[1], &seconds)) {
        ui->ShowProgress(fraction * (1 - VERIFICATION_PROGRESS_FRACTION), seconds);
      } else {
        LOG(ERROR) << "invalid \"progress\" parameters: " << line;
      }
    } else if (command == "set_progress") {
      std::vector<std::string> tokens = android::base::Split(args, " ");
      double fraction;
      if (tokens.size() == 1 && android::base::ParseDouble(tokens[0].c_str(), &fraction)) {
        ui->SetProgress(fraction);
      } else {
        LOG(ERROR) << "invalid \"set_progress\" parameters: " << line;
      }
    } else if (command == "ui_print") {
      ui->PrintOnScreenOnly("%s\n", args.c_str());
      fflush(stdout);
    } else if (command == "wipe_cache") {
      *wipe_cache = true;
    } else if (command == "clear_display") {
      ui->SetBackground(RecoveryUI::NONE);
    } else if (command == "enable_reboot") {
      // packages can explicitly request that they want the user
      // to be able to reboot during installation (useful for
      // debugging packages that don't exit).
      ui->SetEnableReboot(true);
    } else if (command == "retry_update") {
      retry_update = true;
    } else if (command == "log") {
      if (!args.empty()) {
        // Save the logging request from updater and write to last_install later.
        log_buffer->push_back(args);
      } else {
        LOG(ERROR) << "invalid \"log\" parameters: " << line;
      }
    } else {
      LOG(ERROR) << "unknown command [" << command << "]";
    }
  }
  fclose(from_child);

  int status;
  waitpid(pid, &status, 0);

  logger_finished.store(true);
  finish_log_temperature.notify_one();
  temperature_logger.join();

  if (retry_update) {
    return INSTALL_RETRY;
  }
  if (WIFEXITED(status)) {
    if (WEXITSTATUS(status) != EXIT_SUCCESS) {
      LOG(ERROR) << "Error in " << package << " (status " << WEXITSTATUS(status) << ")";
      return INSTALL_ERROR;
    }
  } else if (WIFSIGNALED(status)) {
    LOG(ERROR) << "Error in " << package << " (killed by signal " << WTERMSIG(status) << ")";
    return INSTALL_ERROR;
  } else {
    LOG(FATAL) << "Invalid status code " << status;
  }

  return INSTALL_SUCCESS;
}

// Verifes the compatibility info in a Treble-compatible package. Returns true directly if the
// entry doesn't exist. Note that the compatibility info is packed in a zip file inside the OTA
// package.
bool verify_package_compatibility(ZipArchiveHandle package_zip) {
  LOG(INFO) << "Verifying package compatibility...";

  static constexpr const char* COMPATIBILITY_ZIP_ENTRY = "compatibility.zip";
  ZipString compatibility_entry_name(COMPATIBILITY_ZIP_ENTRY);
  ZipEntry compatibility_entry;
  if (FindEntry(package_zip, compatibility_entry_name, &compatibility_entry) != 0) {
    LOG(INFO) << "Package doesn't contain " << COMPATIBILITY_ZIP_ENTRY << " entry";
    return true;
  }

  std::string zip_content(compatibility_entry.uncompressed_length, '\0');
  int32_t ret;
  if ((ret = ExtractToMemory(package_zip, &compatibility_entry,
                             reinterpret_cast<uint8_t*>(&zip_content[0]),
                             compatibility_entry.uncompressed_length)) != 0) {
    LOG(ERROR) << "Failed to read " << COMPATIBILITY_ZIP_ENTRY << ": " << ErrorCodeString(ret);
    return false;
  }

  ZipArchiveHandle zip_handle;
  ret = OpenArchiveFromMemory(static_cast<void*>(const_cast<char*>(zip_content.data())),
                              zip_content.size(), COMPATIBILITY_ZIP_ENTRY, &zip_handle);
  if (ret != 0) {
    LOG(ERROR) << "Failed to OpenArchiveFromMemory: " << ErrorCodeString(ret);
    return false;
  }

  // Iterate all the entries inside COMPATIBILITY_ZIP_ENTRY and read the contents.
  void* cookie;
  ret = StartIteration(zip_handle, &cookie, nullptr, nullptr);
  if (ret != 0) {
    LOG(ERROR) << "Failed to start iterating zip entries: " << ErrorCodeString(ret);
    CloseArchive(zip_handle);
    return false;
  }
  std::unique_ptr<void, decltype(&EndIteration)> guard(cookie, EndIteration);

  std::vector<std::string> compatibility_info;
  ZipEntry info_entry;
  ZipString info_name;
  while (Next(cookie, &info_entry, &info_name) == 0) {
    std::string content(info_entry.uncompressed_length, '\0');
    int32_t ret = ExtractToMemory(zip_handle, &info_entry, reinterpret_cast<uint8_t*>(&content[0]),
                                  info_entry.uncompressed_length);
    if (ret != 0) {
      LOG(ERROR) << "Failed to read " << info_name.name << ": " << ErrorCodeString(ret);
      CloseArchive(zip_handle);
      return false;
    }
    compatibility_info.emplace_back(std::move(content));
  }
  CloseArchive(zip_handle);

  // VintfObjectRecovery::CheckCompatibility returns zero on success.
  std::string err;
  int result = android::vintf::VintfObjectRecovery::CheckCompatibility(compatibility_info, &err);
  if (result == 0) {
    return true;
  }

  LOG(ERROR) << "Failed to verify package compatibility (result " << result << "): " << err;
  return false;
}

static int really_install_package(const std::string& path, bool* wipe_cache, bool needs_mount,
                                  std::vector<std::string>* log_buffer, int retry_count,
                                  int* max_temperature) {
  ui->SetBackground(RecoveryUI::INSTALLING_UPDATE);
  ui->Print("Finding update package...\n");
  // Give verification half the progress bar...
  ui->SetProgressType(RecoveryUI::DETERMINATE);
  ui->ShowProgress(VERIFICATION_PROGRESS_FRACTION, VERIFICATION_PROGRESS_TIME);
  LOG(INFO) << "Update location: " << path;

  // Map the update package into memory.
  ui->Print("Opening update package...\n");

  if (needs_mount) {
    if (path[0] == '@') {
      ensure_path_mounted(path.substr(1));
    } else {
      ensure_path_mounted(path);
    }
  }

  MemMapping map;
  if (!map.MapFile(path)) {
    LOG(ERROR) << "failed to map file";
    log_buffer->push_back(android::base::StringPrintf("error: %d", kMapFileFailure));
    return INSTALL_CORRUPT;
  }

  // Verify package.
  if (!verify_package(map.addr, map.length)) {
    log_buffer->push_back(android::base::StringPrintf("error: %d", kZipVerificationFailure));
    return INSTALL_CORRUPT;
  }

  // Try to open the package.
  ZipArchiveHandle zip;
  int err = OpenArchiveFromMemory(map.addr, map.length, path.c_str(), &zip);
  if (err != 0) {
    LOG(ERROR) << "Can't open " << path << " : " << ErrorCodeString(err);
    log_buffer->push_back(android::base::StringPrintf("error: %d", kZipOpenFailure));

    CloseArchive(zip);
    return INSTALL_CORRUPT;
  }

  // Additionally verify the compatibility of the package.
  if (!verify_package_compatibility(zip)) {
    log_buffer->push_back(android::base::StringPrintf("error: %d", kPackageCompatibilityFailure));
    CloseArchive(zip);
    return INSTALL_CORRUPT;
  }

  // Verify and install the contents of the package.
  ui->Print("Installing update...\n");
  if (retry_count > 0) {
    ui->Print("Retry attempt: %d\n", retry_count);
  }
  ui->SetEnableReboot(false);
  int result = try_update_binary(path, zip, wipe_cache, log_buffer, retry_count, max_temperature);
  ui->SetEnableReboot(true);
  ui->Print("\n");

  CloseArchive(zip);
  return result;
}

int install_package(const std::string& path, bool* wipe_cache, bool needs_mount, int retry_count) {
  CHECK(!path.empty());
  CHECK(wipe_cache != nullptr);

  modified_flash = true;
  auto start = std::chrono::system_clock::now();

  int start_temperature = GetMaxValueFromThermalZone();
  int max_temperature = start_temperature;

  int result;
  std::vector<std::string> log_buffer;
  if (setup_install_mounts() != 0) {
    LOG(ERROR) << "failed to set up expected mounts for install; aborting";
    result = INSTALL_ERROR;
  } else {
    result = really_install_package(path, wipe_cache, needs_mount, &log_buffer, retry_count,
                                    &max_temperature);
  }

  // Measure the time spent to apply OTA update in seconds.
  std::chrono::duration<double> duration = std::chrono::system_clock::now() - start;
  int time_total = static_cast<int>(duration.count());

  bool has_cache = volume_for_mount_point("/cache") != nullptr;
  // Skip logging the uncrypt_status on devices without /cache.
  if (has_cache) {
    static constexpr const char* UNCRYPT_STATUS = "/cache/recovery/uncrypt_status";
    if (ensure_path_mounted(UNCRYPT_STATUS) != 0) {
      LOG(WARNING) << "Can't mount " << UNCRYPT_STATUS;
    } else {
      std::string uncrypt_status;
      if (!android::base::ReadFileToString(UNCRYPT_STATUS, &uncrypt_status)) {
        PLOG(WARNING) << "failed to read uncrypt status";
      } else if (!android::base::StartsWith(uncrypt_status, "uncrypt_")) {
        LOG(WARNING) << "corrupted uncrypt_status: " << uncrypt_status;
      } else {
        log_buffer.push_back(android::base::Trim(uncrypt_status));
      }
    }
  }

  // The first two lines need to be the package name and install result.
  std::vector<std::string> log_header = {
    path,
    result == INSTALL_SUCCESS ? "1" : "0",
    "time_total: " + std::to_string(time_total),
    "retry: " + std::to_string(retry_count),
  };

  int end_temperature = GetMaxValueFromThermalZone();
  max_temperature = std::max(end_temperature, max_temperature);
  if (start_temperature > 0) {
    log_buffer.push_back("temperature_start: " + std::to_string(start_temperature));
  }
  if (end_temperature > 0) {
    log_buffer.push_back("temperature_end: " + std::to_string(end_temperature));
  }
  if (max_temperature > 0) {
    log_buffer.push_back("temperature_max: " + std::to_string(max_temperature));
  }

  std::string log_content =
      android::base::Join(log_header, "\n") + "\n" + android::base::Join(log_buffer, "\n") + "\n";
  const std::string& install_file = Paths::Get().temporary_install_file();
  if (!android::base::WriteStringToFile(log_content, install_file)) {
    PLOG(ERROR) << "failed to write " << install_file;
  }

  // Write a copy into last_log.
  LOG(INFO) << log_content;

  return result;
}

bool verify_package(const unsigned char* package_data, size_t package_size) {
  static constexpr const char* CERTIFICATE_ZIP_FILE = "/system/etc/security/otacerts.zip";
  std::vector<Certificate> loaded_keys = LoadKeysFromZipfile(CERTIFICATE_ZIP_FILE);
  if (loaded_keys.empty()) {
    LOG(ERROR) << "Failed to load keys";
    return false;
  }
  LOG(INFO) << loaded_keys.size() << " key(s) loaded from " << CERTIFICATE_ZIP_FILE;

  // Verify package.
  ui->Print("Verifying update package...\n");
  auto t0 = std::chrono::system_clock::now();
  int err = verify_file(package_data, package_size, loaded_keys,
                        std::bind(&RecoveryUI::SetProgress, ui, std::placeholders::_1));
  std::chrono::duration<double> duration = std::chrono::system_clock::now() - t0;
  ui->Print("Update package verification took %.1f s (result %d).\n", duration.count(), err);
  if (err != VERIFY_SUCCESS) {
    LOG(ERROR) << "Signature verification failed";
    LOG(ERROR) << "error: " << kZipVerificationFailure;
    return false;
  }
  return true;
}