/*      $OpenBSD: fcntl_dup.c,v 1.3 2017/07/27 10:42:24 bluhm Exp $     */
/*
 *      Written by Artur Grabowski <art@openbsd.org> 2002 Public Domain.
 */
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <err.h>
#include <fcntl.h>

int
main(int argc, char *argv[])
{
        int orgfd, fd1, fd2;
        char temp[] = "/tmp/dup2XXXXXXXXX";

        if ((orgfd = mkstemp(temp)) < 0)
                err(1, "mkstemp");
        remove(temp);

        if (ftruncate(orgfd, 1024) != 0)
                err(1, "ftruncate");

        if ((fd1 = dup(orgfd)) < 0)
                err(1, "dup");

        /* Set close-on-exec */
        if (fcntl(fd1, F_SETFD, 1) != 0)
                err(1, "fcntl(F_SETFD)");

        if ((fd2 = fcntl(fd1, F_DUPFD, 0)) < 0)
                err(1, "fcntl(F_DUPFD)");

        /* Test 2: Was close-on-exec cleared? */
        if (fcntl(fd2, F_GETFD) != 0)
                errx(1, "fcntl(F_DUPFD) didn't clear close-on-exec");

        return 0;
}