server.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <unistd.h>

#define MSG_SIZE 1024
#define LISTEN_Q 32

struct sockFDList   {
    int sockFD;

    struct sockFDList *next;
};

int main(int argc, char *argv[])    {
    int listenFD, newFD, fdmax, i;      // listenFD for listening, newFD for new connection
    char msg[MSG_SIZE];         // buffer for msg transmit
    struct addrinfo hints, *myAI;       // address info
    struct sockaddr_storage remoteAddr; // store client address
    socklen_t sizeAddr;         // sizeof client address
    fd_set masterSet, readSet;      // FD sets for list and read.

    // Clear Sets
    FD_ZERO(&masterSet);
    FD_ZERO(&readSet);

    // Clear hints
    memset(&hints, 0, sizeof hints);

    // Prep hints
    hints.ai_family = AF_INET;
    hints.ai_socktype = SOCK_STREAM;
    hints.ai_flags = AI_PASSIVE;

    // Get local addr info
    getaddrinfo("localhost", argv[1], &hints, &myAI);

    // Get socket for listening
    listenFD = socket(myAI->ai_family, myAI->ai_socktype, myAI->ai_protocol);

    // Bind socket sockFD
    bind(listenFD, myAI->ai_addr, myAI->ai_addrlen);

    // Add sfd to master set
    FD_SET(listenFD, &masterSet);

    // Initialize fdmax
    fdmax = listenFD;


    while(1)    {
        // Copy master
        readSet = masterSet;

        // call select
        if(select(fdmax+1, &readSet, NULL, NULL, NULL) == -1)
            continue;

        // loop through readSet
        for(i=0; i<=fdmax; i++) {
            if(FD_ISSET(i, &readSet))   {   // Active !
                if(i == listenFD)   {   // If listener socket
                    // New Connection, accept
                    sizeAddr = sizeof remoteAddr;
                    newFD = accept(listenFD, (struct sockaddr *)&remoteAddr, &sizeAddr);
                    printf("\n");

                    // Add this connection to my master list
                    FD_SET(newFD, &masterSet);

                    // update fdmax
                    if(newFD > fdmax)
                        fdmax = newFD;
                }
                else    {
                    // Something to read on a socket
                    recv(i, msg, MSG_SIZE, 0);
                    msg[MSG_SIZE] = '\0';

                    // print it.
                    printf("%s\n",msg);
                }
            }
        }
    }


    return 0;
}