freebsd-src/bin/sleep/sleep.c
Konstantin Belousov f6e6dc63ab Simplify argument parser by using sscanf(); simplify usage() by not
refusing to use stdio.
Reduce nesting level in the sleep loop by returning earlier for negative
timeouts.
Limit the maximum timeout to INT_MAX seconds.

Submitted by:	bde
MFC after:	3 weeks
2010-08-02 10:57:56 +00:00

103 lines
3.0 KiB
C

/*-
* 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.
* 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.
*/
#if 0
#ifndef lint
static char const copyright[] =
"@(#) Copyright (c) 1988, 1993, 1994\n\
The Regents of the University of California. All rights reserved.\n";
#endif /* not lint */
#ifndef lint
static char sccsid[] = "@(#)sleep.c 8.3 (Berkeley) 4/2/94";
#endif /* not lint */
#endif
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <ctype.h>
#include <err.h>
#include <limits.h>
#include <signal.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
static void usage(void);
static volatile sig_atomic_t report_requested;
static void
report_request(int signo __unused)
{
report_requested = 1;
}
int
main(int argc, char *argv[])
{
struct timespec time_to_sleep;
double d;
time_t original;
char buf[2];
if (argc != 2)
usage();
if (sscanf(argv[1], "%lf%1s", &d, buf) != 1)
usage();
if (d > INT_MAX)
usage();
if (d <= 0)
return (0);
original = time_to_sleep.tv_sec = (time_t)d;
time_to_sleep.tv_nsec = 1e9 * (d - time_to_sleep.tv_sec);
signal(SIGINFO, report_request);
while (nanosleep(&time_to_sleep, &time_to_sleep) != 0) {
if (report_requested) {
/* Reporting does not bother with nanoseconds. */
warnx("about %d second(s) left out of the original %d",
(int)time_to_sleep.tv_sec, (int)original);
report_requested = 0;
} else
break;
}
return (0);
}
static void
usage(void)
{
fprintf(stderr, "usage: sleep seconds\n");
exit(1);
}