sysdeps/unix/clock_settime.c

   1 /* Copyright (C) 1999, 2000, 2001 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Library General Public License as
   6    published by the Free Software Foundation; either version 2 of the
   7    License, or (at your option) any later version.
   8
   9    The GNU C Library 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 GNU
  12    Library General Public License for more details.
  13
  14    You should have received a copy of the GNU Library General Public
  15    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  16    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17    Boston, MA 02111-1307, USA.  */
  18
  19 #include <errno.h>
  20 #include <time.h>
  21 #include <sys/time.h>
  22 #include <libc-internal.h>
  23
  24
  25 #if HP_TIMING_AVAIL
  26 /* Clock frequency of the processor.  We make it a 64-bit variable
  27    because some jokers are already playing with processors with more
  28    than 4GHz.  */
  29 static hp_timing_t freq;
  30
  31
  32 /* We need the starting time for the process.  */
  33 extern hp_timing_t _dl_cpuclock_offset;
  34
  35
  36 /* This function is defined in the thread library.  */
  37 extern void __pthread_clock_settime (hp_timing_t offset)
  38      __attribute__ ((__weak__));
  39 #endif
  40
  41
  42 /* Set CLOCK to value TP.  */
  43 int
  44 clock_settime (clockid_t clock_id, const struct timespec *tp)
  45 {
  46   struct timeval tv;
  47   int retval;
  48
  49   /* Make sure the time cvalue is OK.  */
  50   if (tp->tv_nsec < 0 || tp->tv_nsec >= 1000000000)
  51     {
  52       __set_errno (EINVAL);
  53       return -1;
  54     }
  55
  56   switch (clock_id)
  57     {
  58     case CLOCK_REALTIME:
  59       TIMESPEC_TO_TIMEVAL (&tv, tp);
  60
  61       retval = settimeofday (&tv, NULL);
  62       break;
  63
  64 #if HP_TIMING_AVAIL
  65     case CLOCK_PROCESS_CPUTIME_ID:
  66     case CLOCK_THREAD_CPUTIME_ID:
  67       {
  68         hp_timing_t tsc;
  69         hp_timing_t usertime;
  70
  71         /* First thing is to get the current time.  */
  72         HP_TIMING_NOW (tsc);
  73
  74         if (__builtin_expect (freq == 0, 0))
  75           {
  76             /* This can only happen if we haven't initialized the `freq'
  77                variable yet.  Do this now. We don't have to protect this
  78                code against multiple execution since all of them should
  79                lead to the same result.  */
  80             freq = __get_clockfreq ();
  81             if (__builtin_expect (freq == 0, 0))
  82               {
  83                 /* Something went wrong.  */
  84                 retval = -1;
  85                 break;
  86               }
  87           }
  88
  89         /* Convert the user-provided time into CPU ticks.  */
  90         usertime = tp->tv_sec * freq + (tp->tv_nsec * freq) / 1000000000ull;
  91
  92         /* Determine the offset and use it as the new base value.  */
  93         if (clock_id != CLOCK_THREAD_CPUTIME_ID
  94             || __pthread_clock_settime == NULL)
  95           _dl_cpuclock_offset = tsc - usertime;
  96         else
  97           __pthread_clock_settime (tsc - usertime);
  98
  99         retval = 0;
 100       }
 101       break;
 102 #endif
 103
 104     default:
 105       __set_errno (EINVAL);
 106       retval = -1;
 107       break;
 108     }
 109
 110   return retval;
 111 }