other.cpp

#include <sys/socket.h>
#include <netinet/in.h>
#include <strings.h>
#include <fcntl.h>


int open_listenfd(int port)
{
    if (port <= 0)
    {
        port = 3000;
    }

    int listenfd, optval=1;
    struct sockaddr_in serveraddr;


    if ((listenfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
        return -1;


    if (setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR,
                   (const void *)&optval , sizeof(int)) < 0)
        return -1;

    bzero((char *) &serveraddr, sizeof(serveraddr));
    serveraddr.sin_family = AF_INET;
    serveraddr.sin_addr.s_addr = htonl(INADDR_ANY);
    serveraddr.sin_port = htons((unsigned short)port);
    if (bind(listenfd, (struct sockaddr *)&serveraddr, sizeof(serveraddr)) < 0)
        return -1;


    if (listen(listenfd, 1024) < 0)
        return -1;

    return listenfd;
}

/*
    make a socket non blocking. If a listen socket is a blocking socket, after it comes out from epoll and accepts the last connection, the next accpet will block, which is not what we want
*/
int make_socket_non_blocking(int fd)
{
    int flags, s;
    flags = fcntl(fd, F_GETFL, 0);
    if (flags == -1)
    {
        return -1;
    }

    flags |= O_NONBLOCK;
    s = fcntl(fd, F_SETFL, flags);
    if (s == -1)
    {
        return -1;
    }

    return 0;
}