bin/sleep/sleep.c

   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  * @(#) Copyright (c) 1988, 1993, 1994 The Regents of the University of California.  All rights reserved.
  34  * @(#)sleep.c  8.3 (Berkeley) 4/2/94
  35  * $FreeBSD: src/bin/sleep/sleep.c,v 1.9.2.1 2001/08/01 05:23:25 obrien Exp $
  36  * $DragonFly: src/bin/sleep/sleep.c,v 1.7 2005/02/27 15:57:15 liamfoy Exp $
  37  */
  38
  39 #include <ctype.h>
  40 #include <limits.h>
  41 #include <locale.h>
  42 #include <stdio.h>
  43 #include <stdlib.h>
  44 #include <time.h>
  45 #include <unistd.h>
  46
  47 static void usage(void);
  48
  49 int
  50 main(int argc, char **argv)
  51 {
  52         struct timespec time_to_sleep;
  53         long l;
  54         int ch, neg;
  55         char *p;
  56
  57         setlocale(LC_ALL, "");
  58
  59         while ((ch = getopt(argc, argv, "")) != -1)
  60                 switch(ch) {
  61                 default:
  62                         usage();
  63                         /* NOTREACHED */
  64                 }
  65         argc -= optind;
  66         argv += optind;
  67
  68         if (argc != 1) {
  69                 usage();
  70                 /* NOTREACHED */
  71         }
  72
  73         p = argv[0];
  74
  75         /* Skip over leading whitespaces. */
  76         while (isspace(*p))
  77                 ++p;
  78
  79         /* Check for optional `+' or `-' sign. */
  80         neg = 0;
  81         if (*p == '-') {
  82                 neg = 1;
  83                 ++p;
  84         }
  85         else if (*p == '+')
  86                 ++p;
  87
  88         /* Calculate seconds. */
  89         if (isdigit(*p)) {
  90                 l = strtol(p, &p, 10);
  91                 if (l > INT_MAX) {
  92                         /*
  93                          * Avoid overflow when `seconds' is huge.  This assumes
  94                          * that the maximum value for a time_t is <= INT_MAX.
  95                          */
  96                         l = INT_MAX;
  97                 }
  98         } else
  99                 l = 0;
 100         time_to_sleep.tv_sec = (time_t)l;
 101
 102         /* Calculate nanoseconds. */
 103         time_to_sleep.tv_nsec = 0;
 104
 105         if (*p == '.') {                /* Decimal point. */
 106                 l = 100000000L;
 107                 do {
 108                         if (isdigit(*++p))
 109                                 time_to_sleep.tv_nsec += (*p - '0') * l;
 110                         else
 111                                 break;
 112                 } while (l /= 10);
 113         }
 114
 115         if (!neg && (time_to_sleep.tv_sec > 0 || time_to_sleep.tv_nsec > 0))
 116                 nanosleep(&time_to_sleep, NULL);
 117
 118         exit(0);
 119 }
 120
 121 static void
 122 usage(void)
 123 {
 124         fprintf(stderr, "usage: sleep seconds\n");
 125         exit(1);
 126 }