/* Copyright (C) 2000-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   Contributed by Kaz Kylheku <kaz@ashi.footprints.net>.

   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; see the file COPYING.LIB.  If

   not, see <http://www.gnu.org/licenses/>.  */

#include <errno.h>

#include <pthread.h>

#include <time.h>

#include "posix-timer.h"

/* Set timer TIMERID to VALUE, returning old value in OVLAUE.  */

int

timer_settime (timer_t timerid, int flags, const struct itimerspec *value,

	       struct itimerspec *ovalue)

{

  struct timer_node *timer;

  struct thread_node *thread = NULL;

  struct timespec now;

  int have_now = 0, need_wakeup = 0;

  int retval = -1;

  timer = timer_id2ptr (timerid);

  if (timer == NULL)

    {

      __set_errno (EINVAL);

      goto bail;

    }

  if (value->it_interval.tv_nsec < 0

      || value->it_interval.tv_nsec >= 1000000000

      || value->it_value.tv_nsec < 0

      || value->it_value.tv_nsec >= 1000000000)

    {

      __set_errno (EINVAL);

      goto bail;

    }

  /* Will need to know current time since this is a relative timer;

     might as well make the system call outside of the lock now! */

  if ((flags & TIMER_ABSTIME) == 0)

    {

      __clock_gettime (timer->clock, &now;;

      have_now = 1;

    }

  pthread_mutex_lock (&__timer_mutex);

  timer_addref (timer);

  /* One final check of timer validity; this one is possible only

     until we have the mutex, because it accesses the inuse flag. */

  if (! timer_valid(timer))

    {

      __set_errno (EINVAL);

      goto unlock_bail;

    }

  if (ovalue != NULL)

    {

      ovalue->it_interval = timer->value.it_interval;

      if (timer->armed)

	{

	  if (! have_now)

	    {

	      pthread_mutex_unlock (&__timer_mutex);

	      __clock_gettime (timer->clock, &now;;

	      have_now = 1;

	      pthread_mutex_lock (&__timer_mutex);

	      timer_addref (timer);

	    }

	  timespec_sub (&ovalue->it_value, &timer->expirytime, &now;;

	}

      else

	{

	  ovalue->it_value.tv_sec = 0;

	  ovalue->it_value.tv_nsec = 0;

	}

    }

  timer->value = *value;

  list_unlink_ip (&timer->links);

  timer->armed = 0;

  thread = timer->thread;

  /* A value of { 0, 0 } causes the timer to be stopped. */

  if (value->it_value.tv_sec != 0

      || __builtin_expect (value->it_value.tv_nsec != 0, 1))

    {

      if ((flags & TIMER_ABSTIME) != 0)

	/* The user specified the expiration time.  */

	timer->expirytime = value->it_value;

      else

	timespec_add (&timer->expirytime, &now, &value->it_value);

      /* Only need to wake up the thread if timer is inserted

	 at the head of the queue. */

      if (thread != NULL)

	need_wakeup = __timer_thread_queue_timer (thread, timer);

      timer->armed = 1;

    }

  retval = 0;

unlock_bail:

  timer_delref (timer);

  pthread_mutex_unlock (&__timer_mutex);

bail:

  if (thread != NULL && need_wakeup)

    __timer_thread_wakeup (thread);

  return retval;

}