/*      $OpenBSD: rcvtimeo.c,v 1.6 2021/12/13 16:56:50 deraadt Exp $    */

/*      Written by Michael Shalayeff, 2002, Public Domain */

#include <sys/socket.h>

#include <netinet/in.h>

#include <signal.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <err.h>

volatile int back;

static void
sigalarm(int sig, siginfo_t *sip, void *scp)
{
        if (!back)
                _exit(1);
}

int
main(int argc, char *argv[])
{
        struct sockaddr_in sin;
        struct sigaction sa;
        struct timeval tv;
        u_char buf[16];
        int s;

        sa.sa_sigaction = &sigalarm;
        sa.sa_flags = SA_SIGINFO;
        sigemptyset(&sa.sa_mask);
        sigaction(SIGALRM, &sa, NULL);

        if ((s = socket(AF_INET, SOCK_DGRAM, 0)) < 0)
                err(1, "socket");

        memset(&sin, 0, sizeof(sin));
        sin.sin_len = sizeof(sin);
        sin.sin_family = AF_INET;
        sin.sin_port = htons(30000);    /* XXX assuming nothing is there */
        sin.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
        if (bind(s, (struct sockaddr *)&sin, sizeof(sin)) < 0)
                err(1, "bind");

        tv.tv_sec = 1;
        tv.tv_usec = 0;
        if (setsockopt(s, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv)) < 0)
                err(1, "setsockopt1");

        back = 0;
        alarm(2);
        errno = 0;
        if (recv(s, buf, sizeof(buf), 0) < 0 && errno != EAGAIN)
                err(1, "recv1");
        back = 1;

        tv.tv_sec = 0;
        tv.tv_usec = 1;
        if (setsockopt(s, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv)) < 0)
                err(1, "setsockopt2");

        back = 0;
        alarm(2);
        errno = 0;
        if (recv(s, buf, sizeof(buf), 0) < 0 && errno != EAGAIN)
                err(1, "recv2");
        back = 1;

        exit (0);
}