+} /* mqtt_reconnect */
+
+/* must hold conf->lock when calling. */
+static int mqtt_connect (mqtt_client_conf_t *conf)
+{
+ char const *client_id;
+ int status;
+
+ if (conf->mosq != NULL)
+ return mqtt_reconnect (conf);
+
+ if (conf->client_id)
+ client_id = conf->client_id;
+ else
+ client_id = hostname_g;
+
+#if LIBMOSQUITTO_MAJOR == 0
+ conf->mosq = mosquitto_new (client_id, /* user data = */ conf);
+#else
+ conf->mosq = mosquitto_new (client_id, conf->clean_session, /* user data = */ conf);
+#endif
+ if (conf->mosq == NULL)
+ {
+ ERROR ("mqtt plugin: mosquitto_new failed");
+ return (-1);
+ }
+
+#if LIBMOSQUITTO_MAJOR != 0
+ if (conf->cacertificatefile) {
+ status = mosquitto_tls_set(conf->mosq, conf->cacertificatefile, NULL,
+ conf->certificatefile, conf->certificatekeyfile, /* pw_callback */NULL);
+ if (status != MOSQ_ERR_SUCCESS) {
+ ERROR ("mqtt plugin: cannot mosquitto_tls_set: %s", mosquitto_strerror(status));
+ mosquitto_destroy (conf->mosq);
+ conf->mosq = NULL;
+ return (-1);
+ }
+
+ status = mosquitto_tls_opts_set(conf->mosq, SSL_VERIFY_PEER, conf->tlsprotocol, conf->ciphersuite);
+ if (status != MOSQ_ERR_SUCCESS) {
+ ERROR ("mqtt plugin: cannot mosquitto_tls_opts_set: %s", mosquitto_strerror(status));
+ mosquitto_destroy (conf->mosq);
+ conf->mosq = NULL;
+ return (-1);
+ }
+
+ status = mosquitto_tls_insecure_set(conf->mosq, false);
+ if (status != MOSQ_ERR_SUCCESS) {
+ ERROR ("mqtt plugin: cannot mosquitto_tls_insecure_set: %s", mosquitto_strerror(status));
+ mosquitto_destroy (conf->mosq);
+ conf->mosq = NULL;
+ return (-1);
+ }
+ }
+#endif
+
+ if (conf->username && conf->password)
+ {
+ status = mosquitto_username_pw_set (conf->mosq, conf->username, conf->password);
+ if (status != MOSQ_ERR_SUCCESS)
+ {
+ char errbuf[1024];
+ ERROR ("mqtt plugin: mosquitto_username_pw_set failed: %s",
+ (status == MOSQ_ERR_ERRNO)
+ ? sstrerror (errno, errbuf, sizeof (errbuf))
+ : mosquitto_strerror (status));
+
+ mosquitto_destroy (conf->mosq);
+ conf->mosq = NULL;
+ return (-1);
+ }
+ }
+
+#if LIBMOSQUITTO_MAJOR == 0
+ status = mosquitto_connect (conf->mosq, conf->host, conf->port,
+ /* keepalive = */ MQTT_KEEPALIVE, /* clean session = */ conf->clean_session);
+#else
+ status = mosquitto_connect (conf->mosq, conf->host, conf->port, MQTT_KEEPALIVE);
+#endif
+ if (status != MOSQ_ERR_SUCCESS)
+ {
+ char errbuf[1024];
+ ERROR ("mqtt plugin: mosquitto_connect failed: %s",
+ (status == MOSQ_ERR_ERRNO)
+ ? sstrerror (errno, errbuf, sizeof (errbuf))
+ : mosquitto_strerror (status));
+
+ mosquitto_destroy (conf->mosq);
+ conf->mosq = NULL;
+ return (-1);
+ }
+
+ if (!conf->publish)
+ {
+ mosquitto_message_callback_set (conf->mosq, on_message);
+
+ status = mosquitto_subscribe (conf->mosq,
+ /* message_id = */ NULL,
+ conf->topic, conf->qos);
+ if (status != MOSQ_ERR_SUCCESS)
+ {
+ ERROR ("mqtt plugin: Subscribing to \"%s\" failed: %s",
+ conf->topic, mosquitto_strerror (status));
+
+ mosquitto_disconnect (conf->mosq);
+ mosquitto_destroy (conf->mosq);
+ conf->mosq = NULL;
+ return (-1);
+ }
+ }
+
+ conf->connected = 1;
+ return (0);
+} /* mqtt_connect */
+
+static void *subscribers_thread (void *arg)
+{
+ mqtt_client_conf_t *conf = arg;
+ int status;
+
+ conf->loop = 1;
+
+ while (conf->loop)
+ {
+ status = mqtt_connect (conf);
+ if (status != 0)
+ {
+ sleep (1);
+ continue;
+ }
+
+ /* The documentation says "0" would map to the default (1000ms), but
+ * that does not work on some versions. */
+#if LIBMOSQUITTO_MAJOR == 0
+ status = mosquitto_loop (conf->mosq, /* timeout = */ 1000 /* ms */);
+#else
+ status = mosquitto_loop (conf->mosq,
+ /* timeout[ms] = */ 1000,
+ /* max_packets = */ 100);
+#endif
+ if (status == MOSQ_ERR_CONN_LOST)
+ {
+ conf->connected = 0;
+ continue;
+ }
+ else if (status != MOSQ_ERR_SUCCESS)
+ {
+ ERROR ("mqtt plugin: mosquitto_loop failed: %s",
+ mosquitto_strerror (status));
+ mosquitto_destroy (conf->mosq);
+ conf->mosq = NULL;
+ conf->connected = 0;
+ continue;
+ }
+
+ DEBUG ("mqtt plugin: mosquitto_loop succeeded.");
+ } /* while (conf->loop) */
+
+ pthread_exit (0);
+} /* void *subscribers_thread */