/* Copyright (C) 1992 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 Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.

You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB.  If
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
Cambridge, MA 02139, USA.  */

#include <ansidecl.h>
#include <errno.h>
#include <unistd.h>
#include <hurd.h>

/* Set the effective user ID of the calling process to UID.  */
int
DEFUN(seteuid, (uid), int uid)
{
  auth_t newauth;
  int i;

  __mutex_lock (&_hurd_idlock);
  if (!_hurd_id_valid)
    {
      error_t err = _HURD_PORT_USE (&_hurd_auth,
				    __auth_getids (port, &_hurd_id));
      if (err)
	{
	  __mutex_unlock (&_hurd_idlock);
	  return __hurd_fail (err);
	}
      _hurd_id_valid = 1;
    }

  for (i = 0; i < _hurd_id.nuids; ++i)
    if (_hurd_id.uids[i] == uid)
      {
	/* We already have this uid.  Swap it with uids[0]
	   so geteuid will return it.  */
	_hurd_id.uids[i] = _hurd_id.uids[0];
	break;
      }

  if (i == _hurd_id.nuids)
    {
      if (_hurd_id.nuids == sizeof (_hurd_id.uids) / sizeof (_hurd_id.uids[0]))
	{
	  __mutex_unlock (&_hurd_idlock);
	  errno = ENOMEM;	/* ? */
	  return -1;
	}
      else
	{
	  _hurd_id.uids[_hurd_id.nuids++] = _hurd_id.uids[0];
	  _hurd_id.uids[0] = uid;
	}
    }

  err = _HURD_PORT_USE (&_hurd_auth,
			__auth_makeauth (port, &_hurd_id, &newauth));
  _hurd_id_valid = 0;
  __mutex_unlock (&_hurd_idlock);

  if (err)
    return __hurd_fail (err);

  err = __setauth (newauth);
  __mach_port_deallocate (__mach_task_self (), newauth);
  return err;
}