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 * 4. Neither the name of the University nor the names of its contributors
14 *    may be used to endorse or promote products derived from this software
15 *    without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30#if 0
31#ifndef lint
32static char const copyright[] =
33"@(#) Copyright (c) 1988, 1993, 1994\n\
34	The Regents of the University of California.  All rights reserved.\n";
35#endif /* not lint */
36
37#ifndef lint
38static char sccsid[] = "@(#)sleep.c	8.3 (Berkeley) 4/2/94";
39#endif /* not lint */
40#endif
41#include <sys/cdefs.h>
42__FBSDID("$FreeBSD: src/bin/sleep/sleep.c,v 1.20 2005/08/07 09:11:38 stefanf Exp $");
43
44#include <ctype.h>
45#include <limits.h>
46#include <stdio.h>
47#include <stdlib.h>
48#include <time.h>
49#include <unistd.h>
50#include <string.h>
51
52void usage(void);
53
54int
55main(int argc, char *argv[])
56{
57	struct timespec time_to_sleep;
58	long l;
59	int neg;
60	char *p;
61
62	if (argc == 2) {
63	    p = argv[1];
64	} else if (argc == 3 && !strcmp("--", argv[1])) {
65	    // POSIX issue:   "sleep -- 3" should be the same as "sleep 3",
66	    // normally getopt makes this kind of thing work, but sleep has
67	    // no options, so we do it "the easy way"
68	    p = argv[2];
69	} else {
70		usage();
71		return(1);
72	}
73
74	/* Skip over leading whitespaces. */
75	while (isspace((unsigned char)*p))
76		++p;
77
78	/* Check for optional `+' or `-' sign. */
79	neg = 0;
80	if (*p == '-') {
81		neg = 1;
82		++p;
83		if (!isdigit((unsigned char)*p) && *p != '.') {
84			usage();
85			return(1);
86		}
87	}
88	else if (*p == '+')
89		++p;
90
91	/* Calculate seconds. */
92	if (isdigit((unsigned char)*p)) {
93		l = strtol(p, &p, 10);
94		if (l > INT_MAX) {
95			/*
96			 * Avoid overflow when `seconds' is huge.  This assumes
97			 * that the maximum value for a time_t is <= INT_MAX.
98			 */
99			l = INT_MAX;
100		}
101	} else
102		l = 0;
103	time_to_sleep.tv_sec = (time_t)l;
104
105	/* Calculate nanoseconds. */
106	time_to_sleep.tv_nsec = 0;
107
108	if (*p == '.') {		/* Decimal point. */
109		l = 100000000L;
110		do {
111			if (isdigit((unsigned char)*++p))
112				time_to_sleep.tv_nsec += (*p - '0') * l;
113			else
114				break;
115			l /= 10;
116		} while (l);
117	}
118
119	if (!neg && (time_to_sleep.tv_sec > 0 || time_to_sleep.tv_nsec > 0))
120		(void)nanosleep(&time_to_sleep, (struct timespec *)NULL);
121
122	return(0);
123}
124
125void
126usage(void)
127{
128	const char msg[] = "usage: sleep seconds\n";
129
130	write(STDERR_FILENO, msg, sizeof(msg) - 1);
131}
132