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/* $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);
}
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