SimpleEventBuilder/event_builder.cxx

#include <arpa/inet.h>
#include <csignal>
#include <cstdint>
#include <cstdio>
#include <cstdlib>
#include <netinet/in.h>
#include <sys/select.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <unistd.h>

#include <sys/time.h>

int makeSocket() {
    int sockfd;
    if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
        perror("socket failed");
        exit(EXIT_FAILURE);
    }
    return sockfd;
}

void bindSocketPort(int server_fd, int port) {
    struct sockaddr_in localAddr;
    localAddr.sin_family = AF_INET;
    localAddr.sin_addr.s_addr = INADDR_ANY;
    localAddr.sin_port = htons(port);

    if (bind(server_fd, (struct sockaddr *)&localAddr, sizeof(localAddr)) < 0) {
        perror("bind failed");
        exit(EXIT_FAILURE);
    }
    printf("FD %d bound to port %d\n", server_fd, port);
}

void startListening(int server_fd) {
    if (listen(server_fd, 3) < 0) {
        perror("listen");
        exit(EXIT_FAILURE);
    }
    printf("FD %d listening to new connections\n", server_fd);
}

int acceptConnection(int server_fd) {
    int client_fd;
    struct sockaddr_in remoteAddr;
    size_t addrlen = sizeof(remoteAddr);
    if ((client_fd = accept(server_fd, (struct sockaddr *)&remoteAddr, (socklen_t *)&addrlen)) < 0) {
        perror("accept");
        exit(EXIT_FAILURE);
    }
    printf("Connection from host %s, port %d, FD %d\n", inet_ntoa(remoteAddr.sin_addr), ntohs(remoteAddr.sin_port), client_fd);
    return client_fd;
}

void term_handler(int signal) {
    printf("Terminated, received SIGNAL %d", signal);
    exit(EXIT_SUCCESS);
}

/*
int main(int argc, char const *argv[]) {
    signal(SIGTERM, term_handler);

    if (argc != 2) {
        printf("Usage: %s portNumber \n", argv[0]);
        exit(EXIT_FAILURE);
    }
    int port = atoi(argv[1]);
    printf("Start socket port %d\n", port);

    int server_fd = makeSocket();
    bindSocketPort(server_fd, port);
    startListening(server_fd);
    int client_fd = acceptConnection(server_fd);

    while (true) {
        uint32_t word;
        ssize_t bytes = read(client_fd, &word, 4);
        if (bytes != 4) {
            perror("Receive failed");
            exit(EXIT_FAILURE);
        }
        printf("[RICEVUTO]\t0x%x\n", word);
    }


    return 0;
}*/

#define TRUE   1 
#define FALSE  0 



int main(int argc, char const *argv[]) {
    signal(SIGTERM, term_handler);

    if (argc != 2) {
        printf("Usage: %s portNumber \n", argv[0]);
        exit(EXIT_FAILURE);
    }
    int port = atoi(argv[1]);
    printf("Start socket port %d\n", port);

    int opt = TRUE;  
    int master_socket , addrlen , new_socket , client_socket[30] , 
          max_clients = 30 , activity, i , valread , sd;  
    int max_sd;

    //set of socket descriptors 
    fd_set readfds;  

    //initialise all client_socket[] to 0 so not checked 
    for (i = 0; i < max_clients; i++)  
    {  
        client_socket[i] = 0;  
    }  

    master_socket = makeSocket();

    //set master socket to allow multiple connections , 
    //this is just a good habit, it will work without this 
    if( setsockopt(master_socket, SOL_SOCKET, SO_REUSEADDR, (char *)&opt, 
          sizeof(opt)) < 0 )  
    {  
        perror("setsockopt");  
        exit(EXIT_FAILURE);  
    }

    bindSocketPort(master_socket, port);
    startListening(master_socket);

    while (true) {
        //clear the socket set 
        FD_ZERO(&readfds);  
     
        //add master socket to set 
        FD_SET(master_socket, &readfds);  
        max_sd = master_socket;


    }

    int client_fd = acceptConnection(server_fd);

    while (true) {
        uint32_t word;
        ssize_t bytes = read(client_fd, &word, 4);
        if (bytes != 4) {
            perror("Receive failed");
            exit(EXIT_FAILURE);
        }
        printf("[RICEVUTO]\t0x%x\n", word);
    }


    return 0;
}