sysdeps/unix/clock_nanosleep.c

   1 /* High-resolution sleep with the specified clock.
   2    Copyright (C) 2000, 2001, 2003 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <assert.h>
  21 #include <errno.h>
  22 #include <time.h>
  23 #include <hp-timing.h>
  24 #include <sysdep-cancel.h>
  25
  26 #if HP_TIMING_AVAIL
  27 # define CPUCLOCK_P(clock) \
  28   ((clock) == CLOCK_PROCESS_CPUTIME_ID                                        \
  29    || ((clock) & ((1 << CLOCK_IDFIELD_SIZE) - 1)) == CLOCK_THREAD_CPUTIME_ID)
  30 #else
  31 # define CPUCLOCK_P(clock) 0
  32 #endif
  33
  34 #ifndef INVALID_CLOCK_P
  35 # define INVALID_CLOCK_P(cl) \
  36   ((cl) < CLOCK_REALTIME || (cl) > CLOCK_THREAD_CPUTIME_ID)
  37 #endif
  38
  39
  40 /* This implementation assumes that these is only a `nanosleep' system
  41    call.  So we have to remap all other activities.  */
  42 int
  43 clock_nanosleep (clockid_t clock_id, int flags, const struct timespec *req,
  44                  struct timespec *rem)
  45 {
  46   struct timespec now;
  47
  48   if (__builtin_expect (req->tv_nsec, 0) < 0
  49       || __builtin_expect (req->tv_nsec, 0) >= 1000000000)
  50     return EINVAL;
  51
  52   if (CPUCLOCK_P (clock_id))
  53     return ENOTSUP;
  54
  55   if (INVALID_CLOCK_P (clock_id))
  56     return EINVAL;
  57
  58 #ifdef SYSDEP_NANOSLEEP
  59   SYSDEP_NANOSLEEP;
  60 #endif
  61
  62   /* If we got an absolute time, remap it.  */
  63   if (flags == TIMER_ABSTIME)
  64     {
  65       long int nsec;
  66       long int sec;
  67
  68       /* Make sure we use safe data types.  */
  69       assert (sizeof (sec) >= sizeof (now.tv_sec));
  70
  71       /* Get the current time for this clock.  */
  72       if (__builtin_expect (clock_gettime (clock_id, &now), 0) != 0)
  73         return errno;
  74
  75       /* Compute the difference.  */
  76       nsec = req->tv_nsec - now.tv_nsec;
  77       sec = req->tv_sec - now.tv_sec - (nsec < 0);
  78       if (sec < 0)
  79         /* The time has already elapsed.  */
  80         return 0;
  81
  82       now.tv_sec = sec;
  83       now.tv_nsec = nsec + (nsec < 0 ? 1000000000 : 0);
  84
  85       /* From now on this is our time.  */
  86       req = &now;
  87
  88       /* Make sure we are not modifying the struct pointed to by REM.  */
  89       rem = NULL;
  90     }
  91   else if (__builtin_expect (flags, 0) != 0)
  92     return EINVAL;
  93   else if (clock_id != CLOCK_REALTIME)
  94     /* Not supported.  */
  95     return ENOTSUP;
  96
  97   return __builtin_expect (nanosleep (req, rem), 0) ? errno : 0;
  98 }