int main(void) { int socket; modbus_param_t mb_param; modbus_mapping_t mb_mapping; int ret; modbus_init_tcp(&mb_param, "127.0.0.1", 1502); ret = modbus_mapping_new(&mb_mapping, MAX_STATUS, 0, MAX_REGISTERS, 0); if (ret == FALSE) { printf("Memory allocation failed\n"); exit(1); } socket = modbus_init_listen_tcp(&mb_param); while (1) { uint8_t query[MAX_MESSAGE_LENGTH]; int query_size; ret = modbus_listen(&mb_param, query, &query_size); if (ret == 0) { modbus_manage_query(&mb_param, query, query_size, &mb_mapping); } else if (ret == CONNECTION_CLOSED) { /* Connection closed by the client, end of server */ break; } else { printf("Error in modbus_listen (%d)\n", ret); } } close(socket); modbus_mapping_free(&mb_mapping); modbus_close(&mb_param); return 0; }
int main(void) { int master_socket; int rc; fd_set refset; fd_set rdset; /* Maximum file descriptor number */ int fdmax; ctx = modbus_new_tcp("127.0.0.1", 1502); mb_mapping = modbus_mapping_new(MODBUS_MAX_READ_BITS, 0, MODBUS_MAX_READ_REGISTERS, 0); if (mb_mapping == NULL) { fprintf(stderr, "Failed to allocate the mapping: %s\n", modbus_strerror(errno)); modbus_free(ctx); return -1; } server_socket = modbus_listen(ctx, NB_CONNECTION); signal(SIGINT, close_sigint); /* Clear the reference set of socket */ FD_ZERO(&refset); /* Add the server socket */ FD_SET(server_socket, &refset); /* Keep track of the max file descriptor */ fdmax = server_socket; for (;;) { rdset = refset; if (select(fdmax+1, &rdset, NULL, NULL, NULL) == -1) { perror("Server select() failure."); close_sigint(1); } /* Run through the existing connections looking for data to be * read */ for (master_socket = 0; master_socket <= fdmax; master_socket++) { if (FD_ISSET(master_socket, &rdset)) { if (master_socket == server_socket) { /* A client is asking a new connection */ socklen_t addrlen; struct sockaddr_in clientaddr; int newfd; /* Handle new connections */ addrlen = sizeof(clientaddr); memset(&clientaddr, 0, sizeof(clientaddr)); newfd = accept(server_socket, (struct sockaddr *)&clientaddr, &addrlen); if (newfd == -1) { perror("Server accept() error"); } else { FD_SET(newfd, &refset); if (newfd > fdmax) { /* Keep track of the maximum */ fdmax = newfd; } printf("New connection from %s:%d on socket %d\n", inet_ntoa(clientaddr.sin_addr), clientaddr.sin_port, newfd); } } else { /* An already connected master has sent a new query */ uint8_t query[MODBUS_TCP_MAX_ADU_LENGTH]; rc = modbus_receive(ctx, master_socket, query); if (rc != -1) { modbus_reply(ctx, query, rc, mb_mapping); } else { /* Connection closed by the client, end of server */ printf("Connection closed on socket %d\n", master_socket); close(master_socket); /* Remove from reference set */ FD_CLR(master_socket, &refset); if (master_socket == fdmax) { fdmax--; } } } } } } return 0; }