#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/epoll.h>
#include <errno.h>
#define MAXEVENTS 64
static int make_socket_non_blocking(int sfd)
{
int flags, s;
flags = fcntl(sfd, F_GETFL, 0);
if (flags == -1) {
perror("fcntl");
return -1;
}
flags |= O_NONBLOCK;
s = fcntl(sfd, F_SETFL, flags);
if (s == -1) {
perror("fcntl");
return -1;
}
return 0;
}
static int create_and_bind(char *port)
{
struct addrinfo hints;
struct addrinfo *result, *rp;
int s, sfd;
memset(&hints, 0, sizeof (struct addrinfo));
hints.ai_family = AF_UNSPEC; /* Return IPv4 and IPv6 choices */
hints.ai_socktype = SOCK_STREAM; /* We want a TCP socket */
hints.ai_flags = AI_PASSIVE; /* All interfaces */
s = getaddrinfo(NULL, port, &hints, &result);
if (s != 0) {
fprintf(stderr, "getaddrinfo: %s\n", gai_strerror (s));
return -1;
}
for (rp = result; rp != NULL; rp = rp->ai_next) {
sfd = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
if (sfd == -1)
continue;
s = bind(sfd, rp->ai_addr, rp->ai_addrlen);
if (s == 0) {
/* We managed to bind successfully! */
break;
}
close(sfd);
}
if (rp == NULL) {
fprintf(stderr, "Could not bind\n");
return -1;
}
freeaddrinfo(result);
return sfd;
}
int main(int argc, char *argv[])
{
int sfd, s;
int efd;
struct epoll_event event;
struct epoll_event *events;
sfd = create_and_bind((char*)"6666");
if (sfd == -1)
goto failure;
printf("--> create socket %d\n", sfd);
s = make_socket_non_blocking(sfd);
if (s == -1)
goto failure;
printf("--> set socket %d non blocking\n", sfd);
s = listen(sfd, SOMAXCONN);
if (s == -1) {
perror("--> listen");
goto failure;
}
efd = epoll_create1(0);
if (efd == -1) {
perror("--> epoll_create");
goto failure;
}
printf("--> create epoll %d\n",efd);
event.data.fd = sfd;
event.events = EPOLLIN | EPOLLET;
s = epoll_ctl(efd, EPOLL_CTL_ADD, sfd, &event);
if (s == -1) {
perror("--> epoll_ctl");
goto failure;
}
printf("--> socket %d was registered to epoll %d\n", sfd, efd);
s = epoll_ctl(efd, EPOLL_CTL_ADD, sfd, &event);
if (s == -1) {
if (errno == EEXIST) {
printf("--> socket %d was already registered to epoll %d, errno = %d\n", sfd, efd, errno);
printf("--> SUCCESS\n");
return EXIT_SUCCESS;
} else {
printf("--> socket %d was already registered to epoll %d, errno should be set to EEXIST, errno = %d\n", sfd, efd, errno);
goto failure;
}
}
failure:
printf("--> FAILURE\n");
return EXIT_FAILURE;
}