osquery-1/osquery/dispatcher/scheduler.h

/**
 *  Copyright (c) 2014-present, Facebook, Inc.
 *  All rights reserved.
 *
 *  This source code is licensed in accordance with the terms specified in
 *  the LICENSE file found in the root directory of this source tree.
 */

#pragma once

#include <chrono>
#include <map>

#include <osquery/dispatcher.h>

#include "osquery/sql/sqlite_util.h"

namespace osquery {

/// A Dispatcher service thread that watches an ExtensionManagerHandler.
class SchedulerRunner : public InternalRunnable {
 public:
  SchedulerRunner(
      unsigned long int timeout,
      size_t interval,
      std::chrono::milliseconds max_time_drift = std::chrono::seconds::zero())
      : InternalRunnable("SchedulerRunner"),
        interval_{std::chrono::seconds{interval}},
        timeout_(timeout),
        time_drift_{std::chrono::milliseconds::zero()},
        max_time_drift_{max_time_drift} {}

 public:
  /// The Dispatcher thread entry point.
  void start() override;

  /// The Dispatcher interrupt point.
  void stop() override {}

  /// Accumulated for some time time drift to compensate.
  std::chrono::milliseconds getCurrentTimeDrift() const noexcept;

 private:
  /// Interval in seconds between schedule steps.
  const std::chrono::milliseconds interval_;

  /// Maximum number of steps.
  const unsigned long int timeout_;

  /// Accumulated for some time time drift to compensate.
  /// It will be either reduced during compensation process or
  /// after exceding the limit @see max_time_drift_
  std::chrono::milliseconds time_drift_;

  const std::chrono::milliseconds max_time_drift_;
};

SQLInternal monitor(const std::string& name, const ScheduledQuery& query);

/// Start querying according to the config's schedule
void startScheduler();

/// Helper scheduler start with variable settings for testing.
void startScheduler(unsigned long int timeout, size_t interval);
}