/* setresgid -- set real group ID, effective group ID, and saved-set group ID

   Copyright (C) 2002-2018 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

   <http://www.gnu.org/licenses/>.  */

#include <errno.h>

#include <unistd.h>

#include <hurd.h>

#include <hurd/id.h>

/* Set the real group ID, effective group ID, and saved-set group ID,

   of the calling process to RGID, EGID, and SGID, respectively.  */

int

__setresgid (gid_t rgid, gid_t egid, gid_t sgid)

{

  auth_t newauth;

  error_t err;

  HURD_CRITICAL_BEGIN;

  __mutex_lock (&_hurd_id.lock);

  err = _hurd_check_ids ();

  if (!err)

    {

      /* Make a new auth handle which has EGID as the first element in the

	 list of effective gids.  */

      uid_t *newgen, *newaux;

      uid_t auxs[2] = { rgid, sgid };

      size_t ngen, naux;

      newgen = _hurd_id.gen.gids;

      ngen = _hurd_id.gen.ngids;

      if (egid != -1)

	{

	  if (_hurd_id.gen.ngids == 0)

	    {

	      /* No effective gids now.  The new set will be just UID.  */

	      newgen = &egi;;

	      ngen = 1;

	    }

	  else

	    {

	      _hurd_id.gen.gids[0] = egid;

	      _hurd_id.valid = 0;

	    }

	}

      newaux = _hurd_id.aux.gids;

      naux = _hurd_id.aux.ngids;

      if (rgid != -1)

	{

	  if (_hurd_id.aux.ngids == 0)

	    {

	      newaux = &rgid;

	      naux = 1;

	    }

	  else

	    {

	      _hurd_id.aux.gids[0] = rgid;

	      _hurd_id.valid = 0;

	    }

	}

      if (sgid != -1)

	{

	  if (rgid == -1)

	    {

	      if (_hurd_id.aux.ngids >= 1)

		auxs[0] = _hurd_id.aux.gids[0];

	      else if (_hurd_id.gen.ngids >= 1)

		auxs[0] = _hurd_id.gen.gids[0];

	      else

		/* Not even an effective GID.

                   Fall back to the only GID we have. */

		auxs[0] = sgid;

	    }

	  if (_hurd_id.aux.ngids <= 1)

	    {

	      /* No saved gids now.  The new set will be just UID.  */

	      newaux = auxs;

	      naux = 2;

	    }

	  else

	    {

	      _hurd_id.aux.gids[1] = sgid;

	      _hurd_id.valid = 0;

	    }

	}

      err = __USEPORT (AUTH, __auth_makeauth

		       (port, NULL, MACH_MSG_TYPE_COPY_SEND, 0,

			_hurd_id.gen.uids, _hurd_id.gen.nuids,

			_hurd_id.aux.uids, _hurd_id.aux.nuids,

			newgen, ngen, newaux, naux,

			&newauth));

    }

  __mutex_unlock (&_hurd_id.lock);

  HURD_CRITICAL_END;

  if (err)

    return __hurd_fail (err);

  /* Install the new handle and reauthenticate everything.  */

  err = __setauth (newauth);

  __mach_port_deallocate (__mach_task_self (), newauth);

  return err;

}

libc_hidden_def (__setresgid)

weak_alias (__setresgid, setresgid)