glibc/sysdeps/mach/hurd/setreuid.c

/* Copyright (C) 1993, 1994, 1995, 1997 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., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

#include <errno.h>
#include <sys/types.h>
#include <unistd.h>
#include <hurd.h>
#include <hurd/id.h>
#include <string.h>

int
__setreuid (ruid, euid)
     uid_t ruid;
     uid_t euid;
{
  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 RUID as the real uid,
	 and EUID as the first element in the list of effective uids.  */

      uid_t *newgen, *newaux;
      size_t ngen, naux;

      newgen = _hurd_id.gen.uids;
      ngen = _hurd_id.gen.nuids;
      if (euid != -1)
	{
	  if (_hurd_id.gen.nuids == 0)
	    {
	      /* No effective uids now.  The new set will be just UID.  */
	      newgen = &euid;
	      ngen = 1;
	    }
	  else
	    {
	      _hurd_id.gen.uids[0] = euid;
	      _hurd_id.valid = 0;
	    }
	}

      newaux = _hurd_id.aux.uids;
      naux = _hurd_id.aux.nuids;
      if (ruid != -1)
	{
	  if (_hurd_id.aux.nuids == 0)
	    {
	      newaux = &ruid;
	      naux = 1;
	    }
	  else
	    {
	      _hurd_id.aux.uids[0] = ruid;
	      _hurd_id.valid = 0;
	    }
	}

      err = __USEPORT (AUTH, __auth_makeauth
		       (port, NULL, MACH_MSG_TYPE_COPY_SEND, 0,
			newgen, ngen, newaux, naux,
			_hurd_id.gen.gids, _hurd_id.gen.ngids,
			_hurd_id.aux.gids, _hurd_id.aux.ngids,
			&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;
}

weak_alias (__setreuid, setreuid)