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/* $OpenBSD: confuse.c,v 1.1 2005/12/07 01:43:39 pedro Exp $ */
/*
* Written by Artur Grabowski <art@openbsd.org> in 2002. Public Domain.
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <err.h>
#include <fcntl.h>
#include <errno.h>
int
main(int argc, char *argv[])
{
char fname[64];
int fd, newfd;
if ((fd = open("/dev/null", O_RDONLY)) < 0)
err(1, "open(/dev/null)");
/* Try to confuse fdescfs by making it open into itself. */
close(fd);
snprintf(fname, sizeof(fname), "/dev/fd/%d", fd);
if ((newfd = open(fname, O_RDONLY)) == fd)
errx(1, "open of %s to %d succeeded, beware.", fname, fd);
if (newfd >= 0)
errx(1, "open(%s) gave us the unexpected %d", fname, fd);
if (errno == ENOENT)
err(1, "open(%s)", fname);
if (errno == ENXIO)
errx(1, "no support for fdesc in kernel");
warn("errno was (%d)", errno);
return 0;
}
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