sleep.c revision 38878 
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: sleep.c,v 1.23 1998/09/05 08:01:26 jb Exp $";
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
47/*
48 * sleep() -	attempt to sleep the specified number of seconds, returning
49 *		any remaining unslept time if interrupted or 0 if the entire
50 *		sleep completes without being interrupted.  Avoid seconds vs
51 *		time_t typing problems by breaking down large times with a
52 *		loop.
53 */
54
55unsigned int
56sleep(seconds)
57	unsigned int seconds;
58{
59	while (seconds != 0) {
60		struct timespec time_to_sleep;
61		struct timespec time_remaining;
62
63		time_to_sleep.tv_sec  = (seconds > INT_MAX) ? INT_MAX : seconds;
64		time_to_sleep.tv_nsec = 0;
65
66		if (nanosleep(&time_to_sleep, &time_remaining) == -1) {
67			/*
68			 * time_remaining only valid if EINTR, else assume no
69			 * time elapsed.
70			 */
71			if (errno == EINTR)
72				seconds -= time_to_sleep.tv_sec - time_remaining.tv_sec;
73			if (time_remaining.tv_nsec)
74				++seconds;
75			break;
76		}
77		seconds -= time_to_sleep.tv_sec;
78	}
79	return(seconds);
80}
81
82