main.cc

// Copyright (c) 2010 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 <string>
#include <vector>

#include <base/at_exit.h>
#include <base/command_line.h>
#include <base/file_util.h>
#include <base/logging.h>
#include <base/string_util.h>
#include <gflags/gflags.h>
#include <glib.h>
#include <metrics/metrics_library.h>
#include <sys/types.h>
#include <sys/stat.h>

#include "update_engine/dbus_constants.h"
#include "update_engine/dbus_service.h"
#include "update_engine/prefs.h"
#include "update_engine/subprocess.h"
#include "update_engine/terminator.h"
#include "update_engine/update_attempter.h"
#include "update_engine/update_check_scheduler.h"

extern "C" {
#include "update_engine/update_engine.dbusserver.h"
}

DEFINE_bool(logtostderr, false,
            "Write logs to stderr instead of to a file in log_dir.");
DEFINE_bool(foreground, false,
            "Don't daemon()ize; run in foreground.");

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

namespace chromeos_update_engine {

gboolean UpdateBootFlags(void* arg) {
  UpdateAttempter* attempter = reinterpret_cast<UpdateAttempter*>(arg);
  if (attempter->status() == UPDATE_STATUS_UPDATED_NEED_REBOOT) {
    // Don't update the flags if there's an update that's just been applied and
    // we're waiting for reboot because we may end up reverting the update.
    return FALSE;  // Don't call this callback again.
  }
  if (attempter->status() != UPDATE_STATUS_IDLE) {
    // To avoid races (e.g., setting a good kernel right after post-install but
    // before the status changes), update the boot flag only if the attempter is
    // idle.
    return TRUE;  // Call this callback again.
  }
  // This is purely best effort. Failures should be logged by Subprocess.
  int unused = 0;
  vector<string> cmd(1, "/usr/sbin/chromeos-setgoodkernel");
  Subprocess::SynchronousExec(cmd, &unused);
  return FALSE;  // Don't call this callback again
}

namespace {

void SetupDbusService(UpdateEngineService* service) {
  DBusGConnection *bus;
  DBusGProxy *proxy;
  GError *error = NULL;

  bus = dbus_g_bus_get(DBUS_BUS_SYSTEM, &error);
  if (!bus) {
    LOG(FATAL) << "Failed to get bus";
  }
  proxy = dbus_g_proxy_new_for_name(bus,
                                    DBUS_SERVICE_DBUS,
                                    DBUS_PATH_DBUS,
                                    DBUS_INTERFACE_DBUS);

  guint32 request_name_ret;
  if (!org_freedesktop_DBus_request_name(proxy,
                                         kUpdateEngineServiceName,
                                         0,
                                         &request_name_ret,
                                         &error)) {
    LOG(FATAL) << "Failed to get name: " << error->message;
  }
  if (request_name_ret != DBUS_REQUEST_NAME_REPLY_PRIMARY_OWNER) {
    g_warning("Got result code %u from requesting name", request_name_ret);
    g_error_free(error);
    LOG(FATAL) << "Got result code " << request_name_ret
               << " from requesting name, but expected "
               << DBUS_REQUEST_NAME_REPLY_PRIMARY_OWNER;
  }
  dbus_g_connection_register_g_object(bus,
                                      "/org/chromium/UpdateEngine",
                                      G_OBJECT(service));
}

void SetupLogSymlink(const string& symlink_path, const string& log_path) {
  // TODO(petkov): To ensure a smooth transition between non-timestamped and
  // timestamped logs, move an existing log to start the first timestamped
  // one. This code can go away once all clients are switched to this version or
  // we stop caring about the old-style logs.
  if (utils::FileExists(symlink_path.c_str()) &&
      !utils::IsSymlink(symlink_path.c_str())) {
    file_util::ReplaceFile(FilePath(symlink_path), FilePath(log_path));
  }
  file_util::Delete(FilePath(symlink_path), true);
  if (symlink(log_path.c_str(), symlink_path.c_str()) == -1) {
    PLOG(ERROR) << "Unable to create symlink " << symlink_path
                << " pointing at " << log_path;
  }
}

string GetTimeAsString(time_t utime) {
  struct tm tm;
  CHECK(localtime_r(&utime, &tm) == &tm);
  char str[16];
  CHECK(strftime(str, sizeof(str), "%Y%m%d-%H%M%S", &tm) == 15);
  return str;
}

string SetupLogFile(const string& kLogsRoot) {
  const string kLogSymlink = kLogsRoot + "/update_engine.log";
  const string kLogsDir = kLogsRoot + "/update_engine";
  const string kLogPath =
      StringPrintf("%s/update_engine.%s",
                   kLogsDir.c_str(),
                   GetTimeAsString(::time(NULL)).c_str());
  mkdir(kLogsDir.c_str(), 0755);
  SetupLogSymlink(kLogSymlink, kLogPath);
  return kLogSymlink;
}

void SetupLogging() {
  // Log to stderr initially.
  logging::InitLogging(NULL,
                       logging::LOG_ONLY_TO_SYSTEM_DEBUG_LOG,
                       logging::DONT_LOCK_LOG_FILE,
                       logging::APPEND_TO_OLD_LOG_FILE);
  if (FLAGS_logtostderr) {
    return;
  }
  const string log_file = SetupLogFile("/var/log");
  logging::InitLogging(log_file.c_str(),
                       logging::LOG_ONLY_TO_FILE,
                       logging::DONT_LOCK_LOG_FILE,
                       logging::APPEND_TO_OLD_LOG_FILE);
}
}  // namespace {}
}  // namespace chromeos_update_engine

int main(int argc, char** argv) {
  ::g_type_init();
  g_thread_init(NULL);
  dbus_g_thread_init();
  base::AtExitManager exit_manager;  // Required for base/rand_util.h.
  chromeos_update_engine::Terminator::Init();
  chromeos_update_engine::Subprocess::Init();
  google::ParseCommandLineFlags(&argc, &argv, true);
  CommandLine::Init(argc, argv);
  chromeos_update_engine::SetupLogging();
  if (!FLAGS_foreground)
    PLOG_IF(FATAL, daemon(0, 0) == 1) << "daemon() failed";

  LOG(INFO) << "Chrome OS Update Engine starting";

  // Ensure that all written files have safe permissions.
  // This is a mask, so we _block_ execute for the owner, and ALL
  // permissions for other users.
  // Done _after_ log file creation.
  umask(S_IXUSR | S_IRWXG | S_IRWXO);

  // Create the single GMainLoop
  GMainLoop* loop = g_main_loop_new(g_main_context_default(), FALSE);

  chromeos_update_engine::Prefs prefs;
  LOG_IF(ERROR, !prefs.Init(FilePath("/var/lib/update_engine/prefs")))
      << "Failed to initialize preferences.";

  MetricsLibrary metrics_lib;
  metrics_lib.Init();

  // Create the update attempter:
  chromeos_update_engine::UpdateAttempter update_attempter(&prefs,
                                                           &metrics_lib);

  // Create the dbus service object:
  dbus_g_object_type_install_info(UPDATE_ENGINE_TYPE_SERVICE,
                                  &dbus_glib_update_engine_service_object_info);
  UpdateEngineService* service =
      UPDATE_ENGINE_SERVICE(g_object_new(UPDATE_ENGINE_TYPE_SERVICE, NULL));
  service->update_attempter_ = &update_attempter;
  update_attempter.set_dbus_service(service);
  chromeos_update_engine::SetupDbusService(service);

  // Schedule periodic update checks.
  chromeos_update_engine::UpdateCheckScheduler scheduler(&update_attempter);
  scheduler.Run();

  // Update boot flags after 45 seconds.
  g_timeout_add_seconds(45,
                        &chromeos_update_engine::UpdateBootFlags,
                        &update_attempter);

  // Run the main loop until exit time:
  g_main_loop_run(loop);

  // Cleanup:
  g_main_loop_unref(loop);
  update_attempter.set_dbus_service(NULL);
  g_object_unref(G_OBJECT(service));

  LOG(INFO) << "Chrome OS Update Engine terminating";
  return 0;
}