main.c

关于tor匿名通信的源代码

    if (nt_service_is_stopping())
      return 0;

#ifndef MS_WINDOWS
    /* Make it easier to tell whether libevent failure is our fault or not. */
    errno = 0;
#endif
    /* All active linked conns should get their read events activated. */
    SMARTLIST_FOREACH(active_linked_connection_lst, connection_t *, conn,
                      event_active(conn->read_event, EV_READ, 1));
    called_loop_once = smartlist_len(active_linked_connection_lst) ? 1 : 0;

    /* poll until we have an event, or the second ends, or until we have
     * some active linked connections to trigger events for. */
    loop_result = event_loop(called_loop_once ? EVLOOP_ONCE : 0);

    /* let catch() handle things like ^c, and otherwise don't worry about it */
    if (loop_result < 0) {
      int e = tor_socket_errno(-1);
      /* let the program survive things like ^z */
      if (e != EINTR && !ERRNO_IS_EINPROGRESS(e)) {
#ifdef HAVE_EVENT_GET_METHOD
        log_err(LD_NET,"libevent call with %s failed: %s [%d]",
                event_get_method(), tor_socket_strerror(e), e);
#else
        log_err(LD_NET,"libevent call failed: %s [%d]",
                tor_socket_strerror(e), e);
#endif
        return -1;
#ifndef MS_WINDOWS
      } else if (e == EINVAL) {
        log_warn(LD_NET, "EINVAL from libevent: should you upgrade libevent?");
        if (got_libevent_error())
          return -1;
#endif
      } else {
        if (ERRNO_IS_EINPROGRESS(e))
          log_warn(LD_BUG,
                   "libevent call returned EINPROGRESS? Please report.");
        log_debug(LD_NET,"libevent call interrupted.");
        /* You can't trust the results of this poll(). Go back to the
         * top of the big for loop. */
        continue;
      }
    }
  }
}

/** Used to implement the SIGNAL control command: if we accept
 * <b>the_signal</b> as a remote pseudo-signal, act on it. */
/* We don't re-use catch() here because:
 *   1. We handle a different set of signals than those allowed in catch.
 *   2. Platforms without signal() are unlikely to define SIGfoo.
 *   3. The control spec is defined to use fixed numeric signal values
 *      which just happen to match the unix values.
 */
void
control_signal_act(int the_signal)
{
  switch (the_signal)
    {
    case 1:
      signal_callback(0,0,(void*)(uintptr_t)SIGHUP);
      break;
    case 2:
      signal_callback(0,0,(void*)(uintptr_t)SIGINT);
      break;
    case 10:
      signal_callback(0,0,(void*)(uintptr_t)SIGUSR1);
      break;
    case 12:
      signal_callback(0,0,(void*)(uintptr_t)SIGUSR2);
      break;
    case 15:
      signal_callback(0,0,(void*)(uintptr_t)SIGTERM);
      break;
    case SIGNEWNYM:
      signal_callback(0,0,(void*)(uintptr_t)SIGNEWNYM);
      break;
    case SIGCLEARDNSCACHE:
      signal_callback(0,0,(void*)(uintptr_t)SIGCLEARDNSCACHE);
      break;
    default:
      log_warn(LD_BUG, "Unrecognized signal number %d.", the_signal);
      break;
    }
}

/** Libevent callback: invoked when we get a signal.
 */
static void
signal_callback(int fd, short events, void *arg)
{
  uintptr_t sig = (uintptr_t)arg;
  (void)fd;
  (void)events;
  switch (sig)
    {
    case SIGTERM:
      log_notice(LD_GENERAL,"Catching signal TERM, exiting cleanly.");
      tor_cleanup();
      exit(0);
      break;
    case SIGINT:
      if (!server_mode(get_options())) { /* do it now */
        log_notice(LD_GENERAL,"Interrupt: exiting cleanly.");
        tor_cleanup();
        exit(0);
      }
      hibernate_begin_shutdown();
      break;
#ifdef SIGPIPE
    case SIGPIPE:
      log_debug(LD_GENERAL,"Caught sigpipe. Ignoring.");
      break;
#endif
    case SIGUSR1:
      /* prefer to log it at INFO, but make sure we always see it */
      dumpstats(get_min_log_level()<LOG_INFO ? get_min_log_level() : LOG_INFO);
      break;
    case SIGUSR2:
      switch_logs_debug();
      log_debug(LD_GENERAL,"Caught USR2, going to loglevel debug. "
                "Send HUP to change back.");
      break;
    case SIGHUP:
      if (do_hup() < 0) {
        log_warn(LD_CONFIG,"Restart failed (config error?). Exiting.");
        tor_cleanup();
        exit(1);
      }
      break;
#ifdef SIGCHLD
    case SIGCHLD:
      while (waitpid(-1,NULL,WNOHANG) > 0) ; /* keep reaping until no more
                                                zombies */
      break;
#endif
    case SIGNEWNYM: {
      time_t now = time(NULL);
      if (time_of_last_signewnym + MAX_SIGNEWNYM_RATE > now) {
        signewnym_is_pending = 1;
        log(LOG_NOTICE, LD_CONTROL,
            "Rate limiting NEWNYM request: delaying by %d second(s)",
            (int)(MAX_SIGNEWNYM_RATE+time_of_last_signewnym-now));
      } else {
        signewnym_impl(now);
      }
      break;
    }
    case SIGCLEARDNSCACHE:
      addressmap_clear_transient();
      break;
  }
}

extern uint64_t rephist_total_alloc;
extern uint32_t rephist_total_num;

/**
 * Write current memory usage information to the log.
 */
static void
dumpmemusage(int severity)
{
  connection_dump_buffer_mem_stats(severity);
  log(severity, LD_GENERAL, "In rephist: "U64_FORMAT" used by %d Tors.",
      U64_PRINTF_ARG(rephist_total_alloc), rephist_total_num);
  dump_routerlist_mem_usage(severity);
  dump_cell_pool_usage(severity);
  buf_dump_freelist_sizes(severity);
  tor_log_mallinfo(severity);
}

/** Write all statistics to the log, with log level 'severity'.  Called
 * in response to a SIGUSR1. */
static void
dumpstats(int severity)
{
  time_t now = time(NULL);
  time_t elapsed;
  int rbuf_cap, wbuf_cap, rbuf_len, wbuf_len;

  log(severity, LD_GENERAL, "Dumping stats:");

  SMARTLIST_FOREACH(connection_array, connection_t *, conn,
  {
    int i = conn_sl_idx;
    log(severity, LD_GENERAL,
        "Conn %d (socket %d) type %d (%s), state %d (%s), created %d secs ago",
        i, conn->s, conn->type, conn_type_to_string(conn->type),
        conn->state, conn_state_to_string(conn->type, conn->state),
        (int)(now - conn->timestamp_created));
    if (!connection_is_listener(conn)) {
      log(severity,LD_GENERAL,
          "Conn %d is to %s:%d.", i,
          safe_str(conn->address), conn->port);
      log(severity,LD_GENERAL,
          "Conn %d: %d bytes waiting on inbuf (len %d, last read %d secs ago)",
          i,
          (int)buf_datalen(conn->inbuf),
          (int)buf_allocation(conn->inbuf),
          (int)(now - conn->timestamp_lastread));
      log(severity,LD_GENERAL,
          "Conn %d: %d bytes waiting on outbuf "
          "(len %d, last written %d secs ago)",i,
          (int)buf_datalen(conn->outbuf),
          (int)buf_allocation(conn->outbuf),
          (int)(now - conn->timestamp_lastwritten));
      if (conn->type == CONN_TYPE_OR) {
        or_connection_t *or_conn = TO_OR_CONN(conn);
        if (or_conn->tls) {
          tor_tls_get_buffer_sizes(or_conn->tls, &rbuf_cap, &rbuf_len,
                                   &wbuf_cap, &wbuf_len);
          log(severity, LD_GENERAL,
              "Conn %d: %d/%d bytes used on openssl read buffer; "
              "%d/%d bytes used on write buffer.",
              i, rbuf_len, rbuf_cap, wbuf_len, wbuf_cap);
        }
      }
    }
    circuit_dump_by_conn(conn, severity); /* dump info about all the circuits
                                           * using this conn */
  });
  log(severity, LD_NET,
      "Cells processed: "U64_FORMAT" padding\n"
      "                 "U64_FORMAT" create\n"
      "                 "U64_FORMAT" created\n"
      "                 "U64_FORMAT" relay\n"
      "                        ("U64_FORMAT" relayed)\n"
      "                        ("U64_FORMAT" delivered)\n"
      "                 "U64_FORMAT" destroy",
      U64_PRINTF_ARG(stats_n_padding_cells_processed),
      U64_PRINTF_ARG(stats_n_create_cells_processed),
      U64_PRINTF_ARG(stats_n_created_cells_processed),
      U64_PRINTF_ARG(stats_n_relay_cells_processed),
      U64_PRINTF_ARG(stats_n_relay_cells_relayed),
      U64_PRINTF_ARG(stats_n_relay_cells_delivered),
      U64_PRINTF_ARG(stats_n_destroy_cells_processed));
  if (stats_n_data_cells_packaged)
    log(severity,LD_NET,"Average packaged cell fullness: %2.3f%%",
        100*(U64_TO_DBL(stats_n_data_bytes_packaged) /
             U64_TO_DBL(stats_n_data_cells_packaged*RELAY_PAYLOAD_SIZE)) );
  if (stats_n_data_cells_received)
    log(severity,LD_NET,"Average delivered cell fullness: %2.3f%%",
        100*(U64_TO_DBL(stats_n_data_bytes_received) /
             U64_TO_DBL(stats_n_data_cells_received*RELAY_PAYLOAD_SIZE)) );

  if (now - time_of_process_start >= 0)
    elapsed = now - time_of_process_start;
  else
    elapsed = 0;

  if (elapsed) {
    log(severity, LD_NET,
        "Average bandwidth: "U64_FORMAT"/%d = %d bytes/sec reading",
        U64_PRINTF_ARG(stats_n_bytes_read),
        (int)elapsed,
        (int) (stats_n_bytes_read/elapsed));
    log(severity, LD_NET,
        "Average bandwidth: "U64_FORMAT"/%d = %d bytes/sec writing",
        U64_PRINTF_ARG(stats_n_bytes_written),
        (int)elapsed,
        (int) (stats_n_bytes_written/elapsed));
  }

  log(severity, LD_NET, "--------------- Dumping memory information:");
  dumpmemusage(severity);

  rep_hist_dump_stats(now,severity);
  rend_service_dump_stats(severity);
  dump_pk_ops(severity);
  dump_distinct_digest_count(severity);
}

/** Called by exit() as we shut down the process.
 */
static void
exit_function(void)
{
  /* NOTE: If we ever daemonize, this gets called immediately.  That's
   * okay for now, because we only use this on Windows.  */
#ifdef MS_WINDOWS
  WSACleanup();
#endif
}

/** Set up the signal handlers for either parent or child. */
void
handle_signals(int is_parent)
{
#ifndef MS_WINDOWS /* do signal stuff only on unix */
  int i;
  static int signals[] = {
    SIGINT,  /* do a controlled slow shutdown */
    SIGTERM, /* to terminate now */
    SIGPIPE, /* otherwise sigpipe kills us */
    SIGUSR1, /* dump stats */
    SIGUSR2, /* go to loglevel debug */
    SIGHUP,  /* to reload config, retry conns, etc */
#ifdef SIGXFSZ
    SIGXFSZ, /* handle file-too-big resource exhaustion */
#endif
    SIGCHLD, /* handle dns/cpu workers that exit */
    -1 };
  static struct event signal_events[16]; /* bigger than it has to be. */
  if (is_parent) {
    for (i = 0; signals[i] >= 0; ++i) {
      signal_set(&signal_events[i], signals[i], signal_callback,
                 (void*)(uintptr_t)signals[i]);
      if (signal_add(&signal_events[i], NULL))
        log_warn(LD_BUG, "Error from libevent when adding event for signal %d",
                 signals[i]);
    }
  } else {
    struct sigaction action;
    action.sa_flags = 0;
    sigemptyset(&action.sa_mask);
    action.sa_handler = SIG_IGN;
    sigaction(SIGINT,  &action, NULL);
    sigaction(SIGTERM, &action, NULL);
    sigaction(SIGPIPE, &action, NULL);
    sigaction(SIGUSR1, &action, NULL);
    sigaction(SIGUSR2, &action, NULL);
    sigaction(SIGHUP,  &action, NULL);
#ifdef SIGXFSZ
    sigaction(SIGXFSZ, &action, NULL);
#endif
  }
#else /* MS windows */
  (void)is_parent;
#endif /* signal stuff */
}

/** Main entry point for the Tor command-line client.
 */
/* static */ int
tor_init(int argc, char *argv[])
{
  char buf[256];
  int i, quiet = 0;
  time_of_process_start = time(NULL);
  if (!connection_array)
    connection_array = smartlist_create();
  if (!closeable_connection_lst)
    closeable_connection_lst = smartlist_create();
  if (!active_linked_connection_lst)
    active_linked_connection_lst = smartlist_create();
  /* Have the log set up with our application name. */
  tor_snprintf(buf, sizeof(buf), "Tor %s", get_version());
  log_set_application_name(buf);
  /* Initialize the history structures. */
  rep_hist_init();
  /* Initialize the service cache.