In this code below (server), I need to be able to receive the client’s query’s, insert them in the FCFS queue and, at the same time, I need those query’s to be executed by the server.
I know the code below doesn’t do what I need, and I’m out of the ideas how to do so. I can’t use semaphores, multi-threading etc.. I’m only allowed to use fork’s and pipe’s, if necessary.

int fork_geral;
    fork_geral = fork();


    if (fork_geral  == -1) {
        perror("fork");
        return 1;
    }

    //son 
    if (fork_geral == 0) {
        while (1){
            handleQueue(queue, argv[1], server_output_info); //will execute the first query in the               queue
        }
        _exit(0);

    } else {
        while(1) {
            while ((bytes_read = read(fd_server, &toRead, sizeof(Msg))) > 0) {
                enQueue(queue, toRead);
                
                //send message to the client that the tasked has been received by the server
                sprintf(toRead.response, "TASK %d Receivedn", fila->tasks++);
                
                int fd_client = open(toRead.pid_path, O_WRONLY);
                if (fd_client == -1) {
                    perror("open");
                    return 1;
                }

                write(fd_client, &toRead, sizeof(toRead));
                close(fd_client);
            }
        }                          
    }    

I’ve already tried to make the server request the son process if he is available to handle a queue,
if so we would execute. I used two pipe’s in this solution but it wasn’t working.