rend_service_intro_has_opened(origin_circuit_t *circuit)
{
  rend_service_t *service;
  char buf[RELAY_PAYLOAD_SIZE];
  char serviceid[REND_SERVICE_ID_LEN_BASE32+1];
  unsigned int expiring_nodes_len, num_ip_circuits, valid_ip_circuits = 0;
  int reason = END_CIRC_REASON_TORPROTOCOL;
  const char *rend_pk_digest;

  tor_assert(circuit->base_.purpose == CIRCUIT_PURPOSE_S_ESTABLISH_INTRO);
  assert_circ_anonymity_ok(circuit, get_options());
  tor_assert(circuit->cpath);
  tor_assert(circuit->rend_data);
  /* XXX: This is version 2 specific (only on supported). */
  rend_pk_digest = (char *) rend_data_get_pk_digest(circuit->rend_data, NULL);

  base32_encode(serviceid, REND_SERVICE_ID_LEN_BASE32+1,
                rend_pk_digest, REND_SERVICE_ID_LEN);

  service = rend_service_get_by_pk_digest(rend_pk_digest);
  if (!service) {
    log_warn(LD_REND, "Unrecognized service ID %s on introduction circuit %u.",
             safe_str_client(serviceid), (unsigned)circuit->base_.n_circ_id);
    reason = END_CIRC_REASON_NOSUCHSERVICE;
    goto err;
  }

  /* Take the current amount of expiring nodes and the current amount of IP
   * circuits and compute how many valid IP circuits we have. */
  expiring_nodes_len = (unsigned int) smartlist_len(service->expiring_nodes);
  num_ip_circuits = count_intro_point_circuits(service);
  /* Let's avoid an underflow. The valid_ip_circuits is initialized to 0 in
   * case this condition turns out false because it means that all circuits
   * are expiring so we need to keep this circuit. */
  if (num_ip_circuits > expiring_nodes_len) {
    valid_ip_circuits = num_ip_circuits - expiring_nodes_len;
  }

  /* If we already have enough introduction circuits for this service,
   * redefine this one as a general circuit or close it, depending.
   * Substract the amount of expiring nodes here because the circuits are
   * still opened. */
  if (valid_ip_circuits > service->n_intro_points_wanted) {
    const or_options_t *options = get_options();
    /* Remove the intro point associated with this circuit, it's being
     * repurposed or closed thus cleanup memory. */
    rend_intro_point_t *intro = find_intro_point(circuit);
    if (intro != NULL) {
      smartlist_remove(service->intro_nodes, intro);
      rend_intro_point_free(intro);
    }

    if (options->ExcludeNodes) {
      /* XXXX in some future version, we can test whether the transition is
         allowed or not given the actual nodes in the circuit.  But for now,
         this case, we might as well close the thing. */
      log_info(LD_CIRC|LD_REND, "We have just finished an introduction "
               "circuit, but we already have enough.  Closing it.");
      reason = END_CIRC_REASON_NONE;
      goto err;
    } else {
      tor_assert(circuit->build_state->is_internal);
      log_info(LD_CIRC|LD_REND, "We have just finished an introduction "
               "circuit, but we already have enough. Redefining purpose to "
               "general; leaving as internal.");

      circuit_change_purpose(TO_CIRCUIT(circuit), CIRCUIT_PURPOSE_C_GENERAL);

      {
        rend_data_free(circuit->rend_data);
        circuit->rend_data = NULL;
      }
      {
        crypto_pk_t *intro_key = circuit->intro_key;
        circuit->intro_key = NULL;
        crypto_pk_free(intro_key);
      }

      circuit_has_opened(circuit);
      goto done;
    }
  }

  log_info(LD_REND,
           "Established circuit %u as introduction point for service %s",
           (unsigned)circuit->base_.n_circ_id, serviceid);
  circuit_log_path(LOG_INFO, LD_REND, circuit);

  /* Send the ESTABLISH_INTRO cell */
  {
    ssize_t len;
    len = encode_establish_intro_cell_legacy(buf, sizeof(buf),
                                      circuit->intro_key,
                                      circuit->cpath->prev->rend_circ_nonce);
    if (len < 0) {
      reason = END_CIRC_REASON_INTERNAL;
      goto err;
    }

    if (relay_send_command_from_edge(0, TO_CIRCUIT(circuit),
                                     RELAY_COMMAND_ESTABLISH_INTRO,
                                     buf, len, circuit->cpath->prev)<0) {
      log_info(LD_GENERAL,
             "Couldn't send introduction request for service %s on circuit %u",
             serviceid, (unsigned)circuit->base_.n_circ_id);
      goto done;
    }
  }

  /* We've attempted to use this circuit */
  pathbias_count_use_attempt(circuit);

  goto done;

 err:
  circuit_mark_for_close(TO_CIRCUIT(circuit), reason);
 done:
  memwipe(buf, 0, sizeof(buf));
  memwipe(serviceid, 0, sizeof(serviceid));

  return;
}

The product writes sensitive information to a log file.