1142425Snectar/*
2142425Snectar * Copyright (c) 2006 Darren Tucker
3142425Snectar *
4142425Snectar * Permission to use, copy, modify, and distribute this software for any
5142425Snectar * purpose with or without fee is hereby granted, provided that the above
6142425Snectar * copyright notice and this permission notice appear in all copies.
7142425Snectar *
8142425Snectar * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9142425Snectar * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10142425Snectar * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11142425Snectar * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12142425Snectar * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13142425Snectar * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14142425Snectar * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15142425Snectar */
16142425Snectar
17142425Snectar#include <sys/types.h>
18142425Snectar#include <sys/stat.h>
19142425Snectar
20142425Snectar#include <fcntl.h>
21142425Snectar#include <stdio.h>
22142425Snectar#include <stdlib.h>
23142425Snectar#include <unistd.h>
24142425Snectar
25142425Snectar#define NUM_OPENS 10
26142425Snectar
27142425Snectarint closefrom(int);
28142425Snectar
29142425Snectarvoid
30142425Snectarfail(char *msg)
31142425Snectar{
32142425Snectar	fprintf(stderr, "closefrom: %s\n", msg);
33142425Snectar	exit(1);
34142425Snectar}
35142425Snectar
36142425Snectarint
37142425Snectarmain(void)
38142425Snectar{
39142425Snectar	int i, max, fds[NUM_OPENS];
40238405Sjkim	char buf[512];
41142425Snectar
42142425Snectar	for (i = 0; i < NUM_OPENS; i++)
43142425Snectar		if ((fds[i] = open("/dev/null", O_RDONLY)) == -1)
44142425Snectar			exit(0);	/* can't test */
45142425Snectar	max = i - 1;
46142425Snectar
47142425Snectar	/* should close last fd only */
48142425Snectar	closefrom(fds[max]);
49142425Snectar	if (close(fds[max]) != -1)
50142425Snectar		fail("failed to close highest fd");
51142425Snectar
52142425Snectar	/* make sure we can still use remaining descriptors */
53160814Ssimon	for (i = 0; i < max; i++)
54160814Ssimon		if (read(fds[i], buf, sizeof(buf)) == -1)
55142425Snectar			fail("closed descriptors it should not have");
56142425Snectar
57142425Snectar	/* should close all fds */
58142425Snectar	closefrom(fds[0]);
59142425Snectar	for (i = 0; i < NUM_OPENS; i++)
60142425Snectar		if (close(fds[i]) != -1)
61142425Snectar			fail("failed to close from lowest fd");
62142425Snectar	return 0;
63142425Snectar}
64142425Snectar