sleep.c revision 90111 
1/*
2 * Copyright (c) 1988, 1993, 1994
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#ifndef lint
35static char const copyright[] =
36"@(#) Copyright (c) 1988, 1993, 1994\n\
37	The Regents of the University of California.  All rights reserved.\n";
38#endif /* not lint */
39
40#ifndef lint
41#if 0
42static char sccsid[] = "@(#)sleep.c	8.3 (Berkeley) 4/2/94";
43#endif
44static const char rcsid[] =
45  "$FreeBSD: head/bin/sleep/sleep.c 90111 2002-02-02 06:50:57Z imp $";
46#endif /* not lint */
47
48#include <ctype.h>
49#include <limits.h>
50#include <stdio.h>
51#include <stdlib.h>
52#include <time.h>
53#include <unistd.h>
54
55void usage(void);
56
57int
58main(int argc, char *argv[])
59{
60	struct timespec time_to_sleep;
61	long l;
62	int ch, neg;
63	char *p;
64
65	while ((ch = getopt(argc, argv, "")) != -1)
66		switch(ch) {
67		case '?':
68		default:
69			usage();
70			/* NOTREACHED */
71		}
72	argc -= optind;
73	argv += optind;
74
75	if (argc != 1) {
76		usage();
77		/* NOTREACHED */
78	}
79
80	p = argv[0];
81
82	/* Skip over leading whitespaces. */
83	while (isspace((unsigned char)*p))
84		++p;
85
86	/* Check for optional `+' or `-' sign. */
87	neg = 0;
88	if (*p == '-') {
89		neg = 1;
90		++p;
91	}
92	else if (*p == '+')
93		++p;
94
95	/* Calculate seconds. */
96	if (isdigit((unsigned char)*p)) {
97		l = strtol(p, &p, 10);
98		if (l > INT_MAX) {
99			/*
100			 * Avoid overflow when `seconds' is huge.  This assumes
101			 * that the maximum value for a time_t is >= INT_MAX.
102			 */
103			l = INT_MAX;
104		}
105	} else
106		l = 0;
107	time_to_sleep.tv_sec = (time_t)l;
108
109	/* Calculate nanoseconds. */
110	time_to_sleep.tv_nsec = 0;
111
112	if (*p == '.') {		/* Decimal point. */
113		l = 100000000L;
114		do {
115			if (isdigit((unsigned char)*++p))
116				time_to_sleep.tv_nsec += (*p - '0') * l;
117			else
118				break;
119		} while (l /= 10);
120	}
121
122	if (!neg && (time_to_sleep.tv_sec > 0 || time_to_sleep.tv_nsec > 0))
123		(void)nanosleep(&time_to_sleep, (struct timespec *)NULL);
124
125	exit(0);
126}
127
128void
129usage(void)
130{
131
132	(void)fprintf(stderr, "usage: sleep seconds\n");
133	exit(1);
134}
135