1/*
2 * Copyright (c) 2006 Darren Tucker
3 *
4 * Permission to use, copy, modify, and distribute this software for any
5 * purpose with or without fee is hereby granted, provided that the above
6 * copyright notice and this permission notice appear in all copies.
7 *
8 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15 */
16
17#include <sys/types.h>
18#include <sys/stat.h>
19
20#include <fcntl.h>
21#include <stdio.h>
22#include <stdlib.h>
23#include <unistd.h>
24
25#define NUM_OPENS 10
26
27int closefrom(int);
28
29void
30fail(char *msg)
31{
32	fprintf(stderr, "closefrom: %s\n", msg);
33	exit(1);
34}
35
36int
37main(void)
38{
39	int i, max, fds[NUM_OPENS];
40	char buf[512];
41
42	for (i = 0; i < NUM_OPENS; i++)
43		if ((fds[i] = open("/dev/null", O_RDONLY)) == -1)
44			exit(0);	/* can't test */
45	max = i - 1;
46
47	/* should close last fd only */
48	closefrom(fds[max]);
49	if (close(fds[max]) != -1)
50		fail("failed to close highest fd");
51
52	/* make sure we can still use remaining descriptors */
53	for (i = 0; i < max; i++)
54		if (read(fds[i], buf, sizeof(buf)) == -1)
55			fail("closed descriptors it should not have");
56
57	/* should close all fds */
58	closefrom(fds[0]);
59	for (i = 0; i < NUM_OPENS; i++)
60		if (close(fds[i]) != -1)
61			fail("failed to close from lowest fd");
62	return 0;
63}
64