sleep.c revision 210696 
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: head/bin/sleep/sleep.c 210696 2010-07-31 17:41:58Z kib $");
43
44#include <ctype.h>
45#include <err.h>
46#include <limits.h>
47#include <signal.h>
48#include <stdint.h>
49#include <stdio.h>
50#include <stdlib.h>
51#include <time.h>
52#include <unistd.h>
53
54static void usage(void);
55
56static volatile sig_atomic_t report_requested;
57static void
58report_request(int signo __unused)
59{
60
61	report_requested = 1;
62}
63
64int
65main(int argc, char *argv[])
66{
67	struct timespec time_to_sleep;
68	long l, original;
69	int neg;
70	char *p;
71
72	if (argc != 2)
73		usage();
74
75	p = argv[1];
76
77	/* Skip over leading whitespaces. */
78	while (isspace((unsigned char)*p))
79		++p;
80
81	/* Check for optional `+' or `-' sign. */
82	neg = 0;
83	if (*p == '-') {
84		neg = 1;
85		++p;
86		if (!isdigit((unsigned char)*p) && *p != '.')
87			usage();
88	}
89	else if (*p == '+')
90		++p;
91
92	/* Calculate seconds. */
93	if (isdigit((unsigned char)*p)) {
94		l = strtol(p, &p, 10);
95
96		/*
97		 * Avoid overflow when `seconds' is huge.  This assumes
98		 * that the maximum value for a time_t is <= INT_MAX.
99		 */
100		if (l > INT_MAX)
101			l = INT_MAX;
102	} else
103		l = 0;
104	time_to_sleep.tv_sec = (time_t)l;
105
106	/* Calculate nanoseconds. */
107	time_to_sleep.tv_nsec = 0;
108
109	if (*p == '.') {		/* Decimal point. */
110		l = 100000000L;
111		do {
112			if (isdigit((unsigned char)*++p))
113				time_to_sleep.tv_nsec += (*p - '0') * l;
114			else
115				break;
116			l /= 10;
117		} while (l);
118	}
119
120	/* Skip over the trailing whitespace. */
121	while (isspace((unsigned char)*p))
122		++p;
123	if (*p != '\0')
124		usage();
125
126	signal(SIGINFO, report_request);
127	if (!neg && (time_to_sleep.tv_sec > 0 || time_to_sleep.tv_nsec > 0)) {
128		original = time_to_sleep.tv_sec;
129		while (nanosleep(&time_to_sleep, &time_to_sleep) != 0) {
130			if (report_requested) {
131				/*
132				 * Reporting does not bother with
133				 * fractions of a second...
134				 */
135				warnx("about %jd second(s) left"
136				    " out of the original %jd",
137				    (intmax_t)time_to_sleep.tv_sec,
138				    (intmax_t)original);
139				report_requested = 0;
140			} else
141				break;
142		}
143	}
144
145	return (0);
146}
147
148static void
149usage(void)
150{
151	static const char msg[] = "usage: sleep seconds\n";
152
153	write(STDERR_FILENO, msg, sizeof(msg) - 1);
154	exit(1);
155}
156