sysdeps/mach/nanosleep.c

   1 /* nanosleep -- sleep for a period specified with a struct timespec
   2    Copyright (C) 2002-2019 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    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <errno.h>
  20 #include <mach.h>
  21 #include <time.h>
  22 #include <unistd.h>
  23
  24 # define timespec_sub(a, b, result)                                           \
  25   do {                                                                        \
  26     (result)->tv_sec = (a)->tv_sec - (b)->tv_sec;                             \
  27     (result)->tv_nsec = (a)->tv_nsec - (b)->tv_nsec;                          \
  28     if ((result)->tv_nsec < 0) {                                              \
  29       --(result)->tv_sec;                                                     \
  30       (result)->tv_nsec += 1000000000;                                        \
  31     }                                                                         \
  32   } while (0)
  33
  34 int
  35 __libc_nanosleep (const struct timespec *requested_time,
  36                   struct timespec *remaining)
  37 {
  38   mach_port_t recv;
  39   struct timespec before;
  40   error_t err;
  41
  42   if (requested_time->tv_sec < 0
  43       || ! valid_nanoseconds (requested_time->tv_nsec))
  44     {
  45       errno = EINVAL;
  46       return -1;
  47     }
  48
  49   const mach_msg_timeout_t ms
  50     = requested_time->tv_sec * 1000
  51     + (requested_time->tv_nsec + 999999) / 1000000;
  52
  53   recv = __mach_reply_port ();
  54
  55   if (remaining != 0)
  56     __clock_gettime (CLOCK_REALTIME, &before);
  57
  58   err = __mach_msg (NULL, MACH_RCV_MSG|MACH_RCV_TIMEOUT|MACH_RCV_INTERRUPT,
  59                     0, 0, recv, ms, MACH_PORT_NULL);
  60   __mach_port_destroy (mach_task_self (), recv);
  61   if (err == EMACH_RCV_INTERRUPTED)
  62     {
  63       if (remaining != 0)
  64         {
  65           struct timespec after, elapsed;
  66           __clock_gettime (CLOCK_REALTIME, &after);
  67           timespec_sub (&after, &before, &elapsed);
  68           timespec_sub (requested_time, &elapsed, remaining);
  69         }
  70
  71       errno = EINTR;
  72       return -1;
  73     }
  74
  75   return 0;
  76 }
  77 weak_alias(__libc_nanosleep, __nanosleep)
  78 libc_hidden_def (__nanosleep)
  79 weak_alias (__libc_nanosleep, nanosleep)