sleep.c revision 30510 
1/*
2 * Copyright (c) 1989, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *	This product includes software developed by the University of
16 *	California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#if defined(LIBC_SCCS) && !defined(lint)
35#if 0
36static char sccsid[] = "@(#)sleep.c	8.1 (Berkeley) 6/4/93";
37#endif
38static char rcsid[] =
39	"$Id$";
40#endif /* LIBC_SCCS and not lint */
41
42#include <errno.h>
43#include <limits.h>
44#include <time.h>
45#include <unistd.h>
46
47unsigned int
48sleep(seconds)
49	unsigned int seconds;
50{
51	struct timespec time_to_sleep;
52	struct timespec time_remaining;
53
54	/*
55	 * Avoid overflow when `seconds' is huge.  This assumes that
56	 * the maximum value for a time_t is >= LONG_MAX.
57	 */
58	if (seconds > LONG_MAX)
59		return (seconds - LONG_MAX + sleep(LONG_MAX));
60
61	time_to_sleep.tv_sec = seconds;
62	time_to_sleep.tv_nsec = 0;
63	if (nanosleep(&time_to_sleep, &time_remaining) != -1)
64		return (0);
65	if (errno != EINTR)
66		return (seconds);		/* best guess */
67	return (time_remaining.tv_sec +
68		(time_remaining.tv_nsec != 0)); /* round up */
69}
70