sysdeps/unix/clock_nanosleep.c

   1 /* High-resolution sleep with the specified clock.
   2    Copyright (C) 2000-2018 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, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <assert.h>
  20 #include <errno.h>
  21 #include <time.h>
  22 #include <hp-timing.h>
  23 #include <sysdep-cancel.h>
  24
  25 #if HP_TIMING_AVAIL
  26 # define CPUCLOCK_P(clock) \
  27   ((clock) == CLOCK_PROCESS_CPUTIME_ID                                        \
  28    || ((clock) & ((1 << CLOCK_IDFIELD_SIZE) - 1)) == CLOCK_THREAD_CPUTIME_ID)
  29 #else
  30 # define CPUCLOCK_P(clock) 0
  31 #endif
  32
  33 #ifndef INVALID_CLOCK_P
  34 # define INVALID_CLOCK_P(cl) \
  35   ((cl) < CLOCK_REALTIME || (cl) > CLOCK_THREAD_CPUTIME_ID)
  36 #endif
  37
  38
  39 /* This implementation assumes that these is only a `nanosleep' system
  40    call.  So we have to remap all other activities.  */
  41 int
  42 __clock_nanosleep (clockid_t clock_id, int flags, const struct timespec *req,
  43                    struct timespec *rem)
  44 {
  45   struct timespec now;
  46
  47   if (__builtin_expect (req->tv_nsec, 0) < 0
  48       || __builtin_expect (req->tv_nsec, 0) >= 1000000000)
  49     return EINVAL;
  50
  51   if (clock_id == CLOCK_THREAD_CPUTIME_ID)
  52     return EINVAL;              /* POSIX specifies EINVAL for this case.  */
  53
  54 #ifdef SYSDEP_NANOSLEEP
  55   SYSDEP_NANOSLEEP;
  56 #endif
  57
  58   if (CPUCLOCK_P (clock_id))
  59     return ENOTSUP;
  60
  61   if (INVALID_CLOCK_P (clock_id))
  62     return EINVAL;
  63
  64   /* If we got an absolute time, remap it.  */
  65   if (flags == TIMER_ABSTIME)
  66     {
  67       long int nsec;
  68       long int sec;
  69
  70       /* Make sure we use safe data types.  */
  71       assert (sizeof (sec) >= sizeof (now.tv_sec));
  72
  73       /* Get the current time for this clock.  */
  74       if (__builtin_expect (clock_gettime (clock_id, &now), 0) != 0)
  75         return errno;
  76
  77       /* Compute the difference.  */
  78       nsec = req->tv_nsec - now.tv_nsec;
  79       sec = req->tv_sec - now.tv_sec - (nsec < 0);
  80       if (sec < 0)
  81         /* The time has already elapsed.  */
  82         return 0;
  83
  84       now.tv_sec = sec;
  85       now.tv_nsec = nsec + (nsec < 0 ? 1000000000 : 0);
  86
  87       /* From now on this is our time.  */
  88       req = &now;
  89
  90       /* Make sure we are not modifying the struct pointed to by REM.  */
  91       rem = NULL;
  92     }
  93   else if (__builtin_expect (flags, 0) != 0)
  94     return EINVAL;
  95   else if (clock_id != CLOCK_REALTIME)
  96     /* Not supported.  */
  97     return ENOTSUP;
  98
  99   return __builtin_expect (nanosleep (req, rem), 0) ? errno : 0;
 100 }
 101 weak_alias (__clock_nanosleep, clock_nanosleep)