Remove more unnecessary uses of calloc.

lib/net_mosq.c

@@ -590,9 +590,10 @@ int _mosquitto_read_string(struct _mosquitto_packet *packet, char **str)
 
 	if(packet->pos+len > packet->remaining_length) return MOSQ_ERR_PROTOCOL;
 
-	*str = _mosquitto_calloc(len+1, sizeof(char));
+	*str = _mosquitto_malloc(len+1);
 	if(*str){
 		memcpy(*str, &(packet->payload[packet->pos]), len);
+		(*str)[len] = '\0';
 		packet->pos += len;
 	}else{
 		return MOSQ_ERR_NOMEM;

lib/send_mosq.c

@@ -143,12 +143,13 @@ int _mosquitto_send_publish(struct mosquitto *mosq, uint16_t mid, const char *to
 					if(cur_topic->remote_prefix){
 						/* This prefix needs adding. */
 						len = strlen(mapped_topic) + strlen(cur_topic->remote_prefix)+1;
-						topic_temp = _mosquitto_calloc(len+1, sizeof(char));
+						topic_temp = _mosquitto_malloc(len+1);
 						if(!topic_temp){
 							_mosquitto_free(mapped_topic);
 							return MOSQ_ERR_NOMEM;
 						}
 						snprintf(topic_temp, len, "%s%s", cur_topic->remote_prefix, mapped_topic);
+						cur_topic->remote_prefix[len] = '\0';
 						_mosquitto_free(mapped_topic);
 						mapped_topic = topic_temp;
 					}

src/read_handle.c

@@ -191,7 +191,7 @@ int mqtt3_handle_publish(struct mosquitto_db *db, struct mosquitto *context)
 			_mosquitto_log_printf(NULL, MOSQ_LOG_DEBUG, "Dropped too large PUBLISH from %s (d%d, q%d, r%d, m%d, '%s', ... (%ld bytes))", context->id, dup, qos, retain, mid, topic, (long)payloadlen);
 			goto process_bad_message;
 		}
-		payload = _mosquitto_malloc(payloadlen+1);
+		payload = _mosquitto_calloc(payloadlen+1, 1);
 		if(!payload){
 			_mosquitto_free(topic);
 			return 1;
@@ -201,7 +201,6 @@ int mqtt3_handle_publish(struct mosquitto_db *db, struct mosquitto *context)
 			_mosquitto_free(payload);
 			return 1;
 		}
-		payload[payloadlen] = '\0';
 	}
 
 	/* Check for topic access */