sysdeps/unix/clock_settime.c

   1 /* Copyright (C) 1999-2004, 2006 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 Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the 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    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    02111-1307 USA.  */
  18
  19 #include <errno.h>
  20 #include <time.h>
  21 #include <sys/time.h>
  22 #include <libc-internal.h>
  23 #include <ldsodefs.h>
  24
  25
  26 #if HP_TIMING_AVAIL
  27 /* Clock frequency of the processor.  We make it a 64-bit variable
  28    because some jokers are already playing with processors with more
  29    than 4GHz.  */
  30 static hp_timing_t freq;
  31
  32
  33 /* This function is defined in the thread library.  */
  34 extern void __pthread_clock_settime (clockid_t clock_id, hp_timing_t offset)
  35      __attribute__ ((__weak__));
  36 #endif
  37
  38
  39 #if HP_TIMING_AVAIL
  40 static int
  41 hp_timing_settime (clockid_t clock_id, const struct timespec *tp)
  42 {
  43   hp_timing_t tsc;
  44   hp_timing_t usertime;
  45
  46   /* First thing is to get the current time.  */
  47   HP_TIMING_NOW (tsc);
  48
  49   if (__builtin_expect (freq == 0, 0))
  50     {
  51       /* This can only happen if we haven't initialized the `freq'
  52          variable yet.  Do this now. We don't have to protect this
  53          code against multiple execution since all of them should lead
  54          to the same result.  */
  55       freq = __get_clockfreq ();
  56       if (__builtin_expect (freq == 0, 0))
  57         /* Something went wrong.  */
  58         return -1;
  59     }
  60
  61   /* Convert the user-provided time into CPU ticks.  */
  62   usertime = tp->tv_sec * freq + (tp->tv_nsec * freq) / 1000000000ull;
  63
  64   /* Determine the offset and use it as the new base value.  */
  65   if (clock_id == CLOCK_PROCESS_CPUTIME_ID
  66       || __pthread_clock_settime == NULL)
  67     GL(dl_cpuclock_offset) = tsc - usertime;
  68   else
  69     __pthread_clock_settime (clock_id, tsc - usertime);
  70
  71   return 0;
  72 }
  73 #endif
  74
  75
  76 /* Set CLOCK to value TP.  */
  77 int
  78 clock_settime (clockid_t clock_id, const struct timespec *tp)
  79 {
  80   int retval;
  81
  82   /* Make sure the time cvalue is OK.  */
  83   if (tp->tv_nsec < 0 || tp->tv_nsec >= 1000000000)
  84     {
  85       __set_errno (EINVAL);
  86       return -1;
  87     }
  88
  89   switch (clock_id)
  90     {
  91 #define HANDLE_REALTIME \
  92       do {                                                                    \
  93         struct timeval tv;                                                    \
  94         TIMESPEC_TO_TIMEVAL (&tv, tp);                                        \
  95                                                                               \
  96         retval = settimeofday (&tv, NULL);                                    \
  97       } while (0)
  98
  99 #ifdef SYSDEP_SETTIME
 100       SYSDEP_SETTIME;
 101 #endif
 102
 103 #ifndef HANDLED_REALTIME
 104     case CLOCK_REALTIME:
 105       HANDLE_REALTIME;
 106       break;
 107 #endif
 108
 109     default:
 110 #ifdef SYSDEP_SETTIME_CPU
 111       SYSDEP_SETTIME_CPU;
 112 #endif
 113 #ifndef HANDLED_CPUTIME
 114 # if HP_TIMING_AVAIL
 115       if (CPUCLOCK_WHICH (clock_id) == CLOCK_PROCESS_CPUTIME_ID
 116           || CPUCLOCK_WHICH (clock_id) == CLOCK_THREAD_CPUTIME_ID)
 117         retval = hp_timing_settime (clock_id, tp);
 118       else
 119 # endif
 120         {
 121           __set_errno (EINVAL);
 122           retval = -1;
 123         }
 124 #endif
 125       break;
 126     }
 127
 128   return retval;
 129 }