Ticket #15081: peerless.c

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

#include <errno.h>
#include <stdio.h>
#include <string.h>

#define panic(n, str) if (n == -1) { perror(str); return 1; }

int main() {
  int sock;
  struct sockaddr_in serv, peer;
  socklen_t peerlen = (socklen_t)sizeof(peer);

  sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
  panic(sock, "socket");

  memset(&serv, 0, sizeof(serv));
  serv.sin_family = AF_INET;
  serv.sin_port = 9123;
  serv.sin_addr.s_addr = INADDR_ANY;

  panic(bind(sock, (struct sockaddr *)&serv, sizeof(serv)), "bind");
  panic(listen(sock, 128), "listen");

  if (getpeername(sock, (struct sockaddr *)&peer, &peerlen) != -1 ||
      errno != ENOTCONN) {
    printf("Expected ENOTCONN, got %d\n", errno);
    return 1;
  }

  return 0;
}