/*
 * sched_setscheduler.c
 * 
 * Description:
 * POSIX thread functions that deal with thread scheduling.
 *
 * --------------------------------------------------------------------------
 *
 *      Pthreads4w - POSIX Threads Library for Win32
 *      Copyright(C) 1998 John E. Bossom
 *      Copyright(C) 1999-2018, Pthreads4w contributors
 *
 *      Homepage: https://sourceforge.net/projects/pthreads4w/
 *
 *      The current list of contributors is contained
 *      in the file CONTRIBUTORS included with the source
 *      code distribution. The list can also be seen at the
 *      following World Wide Web location:
 *      https://sourceforge.net/p/pthreads4w/wiki/Contributors/
 *
 * This file is part of Pthreads4w.
 *
 *    Pthreads4w is free software: you can redistribute it and/or modify
 *    it under the terms of the GNU General Public License as published by
 *    the Free Software Foundation, either version 3 of the License, or
 *    (at your option) any later version.
 *
 *    Pthreads4w 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 General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with Pthreads4w.  If not, see <http://www.gnu.org/licenses/>. *
 */

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

#include "pthread.h"
#include "implement.h"
#include "sched.h"

int
sched_setscheduler (pid_t pid, int policy)
{
  /*
   * Win32 only has one policy which we call SCHED_OTHER.
   * However, we try to provide other valid side-effects
   * such as EPERM and ESRCH errors. Choosing to check
   * for a valid policy last allows us to get the most value out
   * of this function.
   */
  if (0 != pid)
    {
      int selfPid = (int) GetCurrentProcessId ();

      if (pid != selfPid)
	{
	  HANDLE h =
	    OpenProcess (PROCESS_SET_INFORMATION, PTW32_FALSE, (DWORD) pid);

	  if (NULL == h)
	    {
	      PTW32_SET_ERRNO((GetLastError () == (0xFF & ERROR_ACCESS_DENIED)) ? EPERM : ESRCH);
	      return -1;
	    }
	  else
	    CloseHandle(h);
	}
    }

  if (SCHED_OTHER != policy)
    {
      PTW32_SET_ERRNO(ENOSYS);
      return -1;
    }

  /*
   * Don't set anything because there is nothing to set.
   * Just return the current (the only possible) value.
   */
  return SCHED_OTHER;
}