sysdeps/unix/clock_settime.c

   1 /* Copyright (C) 1999-2004, 2006, 2007 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 && !defined HANDLED_CPUTIME
  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
  37
  38 static int
  39 hp_timing_settime (clockid_t clock_id, const struct timespec *tp)
  40 {
  41   hp_timing_t tsc;
  42   hp_timing_t usertime;
  43
  44   /* First thing is to get the current time.  */
  45   HP_TIMING_NOW (tsc);
  46
  47   if (__builtin_expect (freq == 0, 0))
  48     {
  49       /* This can only happen if we haven't initialized the `freq'
  50          variable yet.  Do this now. We don't have to protect this
  51          code against multiple execution since all of them should lead
  52          to the same result.  */
  53       freq = __get_clockfreq ();
  54       if (__builtin_expect (freq == 0, 0))
  55         /* Something went wrong.  */
  56         return -1;
  57     }
  58
  59   /* Convert the user-provided time into CPU ticks.  */
  60   usertime = tp->tv_sec * freq + (tp->tv_nsec * freq) / 1000000000ull;
  61
  62   /* Determine the offset and use it as the new base value.  */
  63   if (clock_id == CLOCK_PROCESS_CPUTIME_ID
  64       || __pthread_clock_settime == NULL)
  65     GL(dl_cpuclock_offset) = tsc - usertime;
  66   else
  67     __pthread_clock_settime (clock_id, tsc - usertime);
  68
  69   return 0;
  70 }
  71 #endif
  72
  73
  74 /* Set CLOCK to value TP.  */
  75 int
  76 clock_settime (clockid_t clock_id, const struct timespec *tp)
  77 {
  78   int retval;
  79
  80   /* Make sure the time cvalue is OK.  */
  81   if (tp->tv_nsec < 0 || tp->tv_nsec >= 1000000000)
  82     {
  83       __set_errno (EINVAL);
  84       return -1;
  85     }
  86
  87   switch (clock_id)
  88     {
  89 #define HANDLE_REALTIME \
  90       do {                                                                    \
  91         struct timeval tv;                                                    \
  92         TIMESPEC_TO_TIMEVAL (&tv, tp);                                        \
  93                                                                               \
  94         retval = settimeofday (&tv, NULL);                                    \
  95       } while (0)
  96
  97 #ifdef SYSDEP_SETTIME
  98       SYSDEP_SETTIME;
  99 #endif
 100
 101 #ifndef HANDLED_REALTIME
 102     case CLOCK_REALTIME:
 103       HANDLE_REALTIME;
 104       break;
 105 #endif
 106
 107     default:
 108 #ifdef SYSDEP_SETTIME_CPU
 109       SYSDEP_SETTIME_CPU;
 110 #endif
 111 #ifndef HANDLED_CPUTIME
 112 # if HP_TIMING_AVAIL
 113       if (CPUCLOCK_WHICH (clock_id) == CLOCK_PROCESS_CPUTIME_ID
 114           || CPUCLOCK_WHICH (clock_id) == CLOCK_THREAD_CPUTIME_ID)
 115         retval = hp_timing_settime (clock_id, tp);
 116       else
 117 # endif
 118         {
 119           __set_errno (EINVAL);
 120           retval = -1;
 121         }
 122 #endif
 123       break;
 124     }
 125
 126   return retval;
 127 }