cros-disks/main.cc

// Copyright (c) 2011 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.

// A simple daemon to detect, mount, and eject removable storage devices.

#include <glib-unix.h>
#include <glib.h>
#include <libudev.h>

#include <algorithm>

#include <dbus-c++/glib-integration.h>
#include <dbus-c++/util.h>

#include <base/command_line.h>
#include <base/files/file_util.h>
#include <base/strings/string_number_conversions.h>
#include <base/strings/string_util.h>
#include <brillo/flag_helper.h>
#include <brillo/syslog_logging.h>
#include <chromeos/dbus/service_constants.h>

#include "cros-disks/daemon.h"

using cros_disks::Daemon;
using std::string;

namespace {

// This callback will be invoked once there is a new device event that
// should be processed by the Daemon::ProcessDeviceEvents().
gboolean DeviceEventCallback(GIOChannel* source,
                             GIOCondition condition,
                             gpointer data) {
  Daemon* daemon = reinterpret_cast<Daemon*>(data);
  daemon->ProcessDeviceEvents();
  // This function should always return true so that the main loop
  // continues to select on device event file descriptor.
  return true;
}

// This callback will be inovked when this process receives SIGINT or SIGTERM.
gboolean TerminationSignalCallback(gpointer data) {
  LOG(INFO) << "Received a signal to terminate the daemon";
  GMainLoop* loop = reinterpret_cast<GMainLoop*>(data);
  g_main_loop_quit(loop);
  // This function can return false to remove this signal handler as we are
  // quitting the main loop anyway.
  return false;
}

}  // namespace

int main(int argc, char** argv) {
  DEFINE_bool(foreground, false, "Run in foreground");
  DEFINE_bool(no_session_manager, false,
              "run without the expectation of a session manager.");
  DEFINE_int32(log_level, 0,
               "Logging level - 0: LOG(INFO), 1: LOG(WARNING), 2: LOG(ERROR), "
               "-1: VLOG(1), -2: VLOG(2), ...");
  brillo::FlagHelper::Init(argc, argv, "Chromium OS Disk Daemon");

  brillo::InitLog(brillo::kLogToSyslog | brillo::kLogToStderrIfTty);
  logging::SetMinLogLevel(FLAGS_log_level);

  if (!FLAGS_foreground)
    PLOG_IF(FATAL, ::daemon(0, 0) == 1) << "Failed to create daemon";

  LOG(INFO) << "Creating a GMainLoop";
  GMainLoop* loop = g_main_loop_new(g_main_context_default(), FALSE);
  CHECK(loop) << "Failed to create a GMainLoop";

  // Set up a signal handler for handling SIGINT and SIGTERM.
  g_unix_signal_add(SIGINT, TerminationSignalCallback, loop);
  g_unix_signal_add(SIGTERM, TerminationSignalCallback, loop);

  LOG(INFO) << "Creating the D-Bus dispatcher";
  DBus::Glib::BusDispatcher dispatcher;
  DBus::default_dispatcher = &dispatcher;
  dispatcher.attach(nullptr);

  LOG(INFO) << "Creating the cros-disks server";
  DBus::Connection server_conn = DBus::Connection::SystemBus();
  CHECK(server_conn.acquire_name(cros_disks::kCrosDisksServiceName))
      << "Failed to acquire D-Bus name " << cros_disks::kCrosDisksServiceName;

  bool has_session_manager = !FLAGS_no_session_manager;
  Daemon daemon(&server_conn, has_session_manager);
  daemon.Initialize();

  // Set up a monitor for handling device events.
  GIOChannel* device_event_channel =
      g_io_channel_unix_new(daemon.GetDeviceEventDescriptor());
  g_io_channel_set_close_on_unref(device_event_channel, TRUE);
  CHECK_EQ(G_IO_STATUS_NORMAL,
           g_io_channel_set_encoding(device_event_channel, nullptr, nullptr));
  g_io_add_watch_full(device_event_channel, G_PRIORITY_HIGH_IDLE,
                      GIOCondition(G_IO_IN | G_IO_PRI),  // Ignore errors.
                      DeviceEventCallback, &daemon, nullptr);
  g_main_loop_run(loop);

  LOG(INFO) << "Cleaning up and exiting";
  g_main_loop_unref(loop);

  return 0;
}