/* nanosleep -- sleep for a period specified with a struct timespec
   Copyright (C) 2002-2019 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <https://www.gnu.org/licenses/>.  */

#include <errno.h>
#include <mach.h>
#include <time.h>
#include <unistd.h>

# define timespec_sub(a, b, result)					      \
  do {									      \
    (result)->tv_sec = (a)->tv_sec - (b)->tv_sec;			      \
    (result)->tv_nsec = (a)->tv_nsec - (b)->tv_nsec;			      \
    if ((result)->tv_nsec < 0) {					      \
      --(result)->tv_sec;						      \
      (result)->tv_nsec += 1000000000;					      \
    }									      \
  } while (0)

int
__libc_nanosleep (const struct timespec *requested_time,
                  struct timespec *remaining)
{
  mach_port_t recv;
  struct timespec before;
  error_t err;

  if (requested_time->tv_sec < 0
      || ! valid_nanoseconds (requested_time->tv_nsec))
    {
      errno = EINVAL;
      return -1;
    }

  const mach_msg_timeout_t ms
    = requested_time->tv_sec * 1000
    + (requested_time->tv_nsec + 999999) / 1000000;

  recv = __mach_reply_port ();

  if (remaining != 0)
    __clock_gettime (CLOCK_REALTIME, &before);

  err = __mach_msg (NULL, MACH_RCV_MSG|MACH_RCV_TIMEOUT|MACH_RCV_INTERRUPT,
                    0, 0, recv, ms, MACH_PORT_NULL);
  __mach_port_destroy (mach_task_self (), recv);
  if (err == EMACH_RCV_INTERRUPTED)
    {
      if (remaining != 0)
	{
	  struct timespec after, elapsed;
	  __clock_gettime (CLOCK_REALTIME, &after);
	  timespec_sub (&after, &before, &elapsed);
	  timespec_sub (requested_time, &elapsed, remaining);
	}

      errno = EINTR;
      return -1;
    }

  return 0;
}
weak_alias(__libc_nanosleep, __nanosleep)
libc_hidden_def (__nanosleep)
weak_alias (__libc_nanosleep, nanosleep)