freebsd-dev/bin/sleep/sleep.c

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/*
* Copyright (c) 1988, 1993, 1994
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
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#if 0
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#ifndef lint
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static char const copyright[] =
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"@(#) Copyright (c) 1988, 1993, 1994\n\
The Regents of the University of California. All rights reserved.\n";
#endif /* not lint */
#ifndef lint
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static char sccsid[] = "@(#)sleep.c 8.3 (Berkeley) 4/2/94";
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#endif /* not lint */
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#endif
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#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
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#include <ctype.h>
#include <limits.h>
#include <stdio.h>
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#include <stdlib.h>
#include <time.h>
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#include <unistd.h>
void usage(void);
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int
main(int argc, char *argv[])
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{
struct timespec time_to_sleep;
long l;
int neg;
char *p;
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if (argc != 2) {
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usage();
return(1);
}
p = argv[1];
/* Skip over leading whitespaces. */
while (isspace((unsigned char)*p))
++p;
/* Check for optional `+' or `-' sign. */
neg = 0;
if (*p == '-') {
neg = 1;
++p;
if (!isdigit((unsigned char)*p) && *p != '.') {
usage();
return(1);
}
}
else if (*p == '+')
++p;
/* Calculate seconds. */
if (isdigit((unsigned char)*p)) {
l = strtol(p, &p, 10);
if (l > INT_MAX) {
/*
* Avoid overflow when `seconds' is huge. This assumes
* that the maximum value for a time_t is >= INT_MAX.
*/
l = INT_MAX;
}
} else
l = 0;
time_to_sleep.tv_sec = (time_t)l;
/* Calculate nanoseconds. */
time_to_sleep.tv_nsec = 0;
if (*p == '.') { /* Decimal point. */
l = 100000000L;
do {
if (isdigit((unsigned char)*++p))
time_to_sleep.tv_nsec += (*p - '0') * l;
else
break;
l /= 10;
} while (l);
}
if (!neg && (time_to_sleep.tv_sec > 0 || time_to_sleep.tv_nsec > 0))
(void)nanosleep(&time_to_sleep, (struct timespec *)NULL);
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return(0);
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}
void
usage(void)
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{
const char msg[] = "usage: sleep seconds\n";
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write(STDERR_FILENO, msg, sizeof(msg) - 1);
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}