src/sleep.c

   1 /* sleep - delay for a specified amount of time.
   2    Copyright (C) 84, 1991-1997, 1999-2002 Free Software Foundation, Inc.
   3
   4    This program is free software; you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 2, or (at your option)
   7    any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program; if not, write to the Free Software Foundation,
  16    Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  17
  18 #include <config.h>
  19 #include <stdio.h>
  20 #include <assert.h>
  21 #include <sys/types.h>
  22 #include <time.h>
  23 #include <getopt.h>
  24
  25 #define USE_CLOCK_GETTIME (defined CLOCK_REALTIME && HAVE_CLOCK_GETTIME)
  26 #if ! USE_CLOCK_GETTIME
  27 # include <sys/time.h>
  28 #endif
  29
  30 #ifndef TIME_T_MAX
  31 # define TIME_T_MAX TYPE_MAXIMUM (time_t)
  32 #endif
  33
  34 #include "system.h"
  35 #include "error.h"
  36 #include "long-options.h"
  37 #include "timespec.h"
  38 #include "xstrtod.h"
  39 #include "closeout.h"
  40
  41 #if HAVE_FENV_H
  42 # include <fenv.h>
  43 #endif
  44
  45 /* Tell the compiler that non-default rounding modes are used.  */
  46 #if 199901 <= __STDC_VERSION__
  47  #pragma STDC FENV_ACCESS ON
  48 #endif
  49
  50 /* The official name of this program (e.g., no `g' prefix).  */
  51 #define PROGRAM_NAME "sleep"
  52
  53 #define AUTHORS N_ ("Jim Meyering and Paul Eggert")
  54
  55 /* The name by which this program was run. */
  56 char *program_name;
  57
  58 static struct option const long_options[] =
  59 {
  60   {0, 0, 0, 0}
  61 };
  62
  63 void
  64 usage (int status)
  65 {
  66   if (status != 0)
  67     fprintf (stderr, _("Try `%s --help' for more information.\n"),
  68              program_name);
  69   else
  70     {
  71       printf (_("\
  72 Usage: %s NUMBER[SUFFIX]...\n\
  73   or:  %s OPTION\n\
  74 Pause for NUMBER seconds.  SUFFIX may be `s' for seconds (the default),\n\
  75 `m' for minutes, `h' for hours or `d' for days.  Unlike most implementations\n\
  76 that require NUMBER be an integer, here NUMBER may be an arbitrary floating\n\
  77 point number.\n\
  78 \n\
  79 "),
  80               program_name, program_name);
  81       fputs (HELP_OPTION_DESCRIPTION, stdout);
  82       fputs (VERSION_OPTION_DESCRIPTION, stdout);
  83       printf (_("\nReport bugs to <%s>.\n"), PACKAGE_BUGREPORT);
  84     }
  85   exit (status);
  86 }
  87
  88 /* Given a floating point value *X, and a suffix character, SUFFIX_CHAR,
  89    scale *X by the multiplier implied by SUFFIX_CHAR.  SUFFIX_CHAR may
  90    be the NUL byte or `s' to denote seconds, `m' for minutes, `h' for
  91    hours, or `d' for days.  If SUFFIX_CHAR is invalid, don't modify *X
  92    and return nonzero.  Otherwise return zero.  */
  93
  94 static int
  95 apply_suffix (double *x, char suffix_char)
  96 {
  97   unsigned int multiplier;
  98
  99   switch (suffix_char)
 100     {
 101     case 0:
 102     case 's':
 103       multiplier = 1;
 104       break;
 105     case 'm':
 106       multiplier = 60;
 107       break;
 108     case 'h':
 109       multiplier = 60 * 60;
 110       break;
 111     case 'd':
 112       multiplier = 60 * 60 * 24;
 113       break;
 114     default:
 115       multiplier = 0;
 116     }
 117
 118   if (multiplier == 0)
 119     return 1;
 120
 121   *x *= multiplier;
 122
 123   return 0;
 124 }
 125
 126 /* Subtract the `struct timespec' values X and Y,
 127    storing the difference in DIFF.
 128    Return 1 if the difference is positive, otherwise 0.
 129    Derived from code in the GNU libc manual.  */
 130
 131 static int
 132 timespec_subtract (struct timespec *diff,
 133                    const struct timespec *x, struct timespec *y)
 134 {
 135   /* Perform the carry for the later subtraction by updating Y. */
 136   if (x->tv_nsec < y->tv_nsec)
 137     {
 138       int nsec = (y->tv_nsec - x->tv_nsec) / 1000000000 + 1;
 139       y->tv_nsec -= 1000000000 * nsec;
 140       y->tv_sec += nsec;
 141     }
 142
 143   if (1000000000 < x->tv_nsec - y->tv_nsec)
 144     {
 145       int nsec = (y->tv_nsec - x->tv_nsec) / 1000000000;
 146       y->tv_nsec += 1000000000 * nsec;
 147       y->tv_sec -= nsec;
 148     }
 149
 150   /* Compute the time remaining to wait.
 151      `tv_nsec' is certainly positive. */
 152   diff->tv_sec = x->tv_sec - y->tv_sec;
 153   diff->tv_nsec = x->tv_nsec - y->tv_nsec;
 154
 155   /* Return 1 if result is positive. */
 156   return y->tv_sec < x->tv_sec;
 157 }
 158
 159 static struct timespec *
 160 clock_get_realtime (struct timespec *ts)
 161 {
 162   int fail;
 163 #if USE_CLOCK_GETTIME
 164   fail = clock_gettime (CLOCK_REALTIME, ts);
 165 #else
 166   struct timeval tv;
 167   fail = gettimeofday (&tv, NULL);
 168   if (!fail)
 169     {
 170       ts->tv_sec = tv.tv_sec;
 171       ts->tv_nsec = 1000 * tv.tv_usec;
 172     }
 173 #endif
 174
 175   if (fail)
 176     error (1, errno, _("cannot read realtime clock"));
 177
 178   return ts;
 179 }
 180
 181 int
 182 main (int argc, char **argv)
 183 {
 184   int i;
 185   double seconds = 0.0;
 186   double ns;
 187   int c;
 188   int fail = 0;
 189   int forever;
 190   struct timespec ts_start;
 191   struct timespec ts_stop;
 192   struct timespec ts_sleep;
 193
 194   /* Record start time.  */
 195   clock_get_realtime (&ts_start);
 196
 197   program_name = argv[0];
 198   setlocale (LC_ALL, "");
 199   bindtextdomain (PACKAGE, LOCALEDIR);
 200   textdomain (PACKAGE);
 201
 202   atexit (close_stdout);
 203
 204   parse_long_options (argc, argv, PROGRAM_NAME, GNU_PACKAGE, VERSION,
 205                       AUTHORS, usage);
 206
 207   while ((c = getopt_long (argc, argv, "", long_options, NULL)) != -1)
 208     {
 209       switch (c)
 210         {
 211         case 0:
 212           break;
 213
 214         default:
 215           usage (1);
 216         }
 217     }
 218
 219   if (argc == 1)
 220     {
 221       error (0, 0, _("too few arguments"));
 222       usage (1);
 223     }
 224
 225 #ifdef FE_UPWARD
 226   /* Always round up, since we must sleep for at least the specified
 227      interval.  */
 228   fesetround (FE_UPWARD);
 229 #endif
 230
 231   for (i = optind; i < argc; i++)
 232     {
 233       double s;
 234       const char *p;
 235       if (xstrtod (argv[i], &p, &s)
 236           /* Nonnegative interval.  */
 237           || ! (0 <= s)
 238           /* No extra chars after the number and an optional s,m,h,d char.  */
 239           || (*p && *(p+1))
 240           /* Check any suffix char and update S based on the suffix.  */
 241           || apply_suffix (&s, *p))
 242         {
 243           error (0, 0, _("invalid time interval `%s'"), argv[i]);
 244           fail = 1;
 245         }
 246
 247       seconds += s;
 248     }
 249
 250   if (fail)
 251     usage (1);
 252
 253   /* Separate whole seconds from nanoseconds.
 254      Be careful to detect any overflow.  */
 255   ts_sleep.tv_sec = seconds;
 256   ns = 1e9 * (seconds - ts_sleep.tv_sec);
 257   forever = ! (ts_sleep.tv_sec <= seconds && 0 <= ns && ns <= 1e9);
 258   ts_sleep.tv_nsec = ns;
 259
 260   /* Round up to the next whole number, if necessary, so that we
 261      always sleep for at least the requested amount of time.  */
 262   ts_sleep.tv_nsec += (ts_sleep.tv_nsec < ns);
 263
 264   /* Normalize the interval length.  nanosleep requires this.  */
 265   if (1000000000 <= ts_sleep.tv_nsec)
 266     {
 267       time_t t = ts_sleep.tv_sec + 1;
 268
 269       /* Detect integer overflow.  */
 270       forever |= (t < ts_sleep.tv_sec);
 271
 272       ts_sleep.tv_sec = t;
 273       ts_sleep.tv_nsec -= 1000000000;
 274     }
 275
 276   ts_stop.tv_sec = ts_start.tv_sec + ts_sleep.tv_sec;
 277   ts_stop.tv_nsec = ts_start.tv_nsec + ts_sleep.tv_nsec;
 278   if (1000000000 <= ts_stop.tv_nsec)
 279     {
 280       ++ts_stop.tv_sec;
 281       ts_stop.tv_nsec -= 1000000000;
 282     }
 283
 284   /* Detect integer overflow.  */
 285   forever |= (ts_stop.tv_sec < ts_start.tv_sec
 286               || (ts_stop.tv_sec == ts_start.tv_sec
 287                   && ts_stop.tv_nsec < ts_start.tv_nsec));
 288
 289   if (forever)
 290     {
 291       /* Fix ts_sleep and ts_stop, which may be garbage due to overflow.  */
 292       ts_sleep.tv_sec = ts_stop.tv_sec = TIME_T_MAX;
 293       ts_sleep.tv_nsec = ts_stop.tv_nsec = 999999999;
 294     }
 295
 296   while (nanosleep (&ts_sleep, NULL) != 0
 297          && timespec_subtract (&ts_sleep, &ts_stop,
 298                                clock_get_realtime (&ts_start)))
 299     continue;
 300
 301   exit (0);
 302 }