sysdeps/mach/hurd/setgid.c

   1 /* Copyright (C) 1991 Free Software Foundation, Inc.
   2 This file is part of the GNU C Library.
   3
   4 The GNU C Library is free software; you can redistribute it and/or
   5 modify it under the terms of the GNU Library General Public License as
   6 published by the Free Software Foundation; either version 2 of the
   7 License, or (at your option) any later version.
   8
   9 The GNU C Library is distributed in the hope that it will be useful,
  10 but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12 Library General Public License for more details.
  13
  14 You should have received a copy of the GNU Library General Public
  15 License along with the GNU C Library; see the file COPYING.LIB.  If
  16 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  17 Cambridge, MA 02139, USA.  */
  18
  19 #include <ansidecl.h>
  20 #include <errno.h>
  21 #include <unistd.h>
  22
  23 /* Set the group ID of the calling process to UID.
  24    If the calling process is the super-group, the real
  25    and effective group IDs, and the saved set-group-ID to UID;
  26    if not, the effective group ID is set to GID.  */
  27 int
  28 DEFUN(__setgid, (gid), gid_t gid)
  29 {
  30   auth_t newauth;
  31   int i;
  32
  33   __mutex_lock (&_hurd_idlock);
  34   if (!_hurd_id_valid)
  35     {
  36       error_t err = __auth_getids (_hurd_auth, &_hurd_id);
  37       if (err)
  38         {
  39           __mutex_unlock (&_hurd_idlock);
  40           return __hurd_fail (err);
  41         }
  42       _hurd_id_valid = 1;
  43     }
  44
  45   for (i = 0; i < _hurd_id.ngroups; ++i)
  46     if (_hurd_id.gids[i] == gid)
  47       {
  48         /* We already have this gid.  Swap it with gids[0]
  49            so getgid will return it.  */
  50         _hurd_id.gids[i] = _hurd_id.gids[0];
  51         break;
  52       }
  53
  54   if (i == _hurd_id.ngroups)
  55     {
  56       if (_hurd_id.ngroups == (sizeof (_hurd_id.gids) /
  57                                sizeof (_hurd_id.gids[0])))
  58         {
  59           __mutex_unlock (&_hurd_idlock);
  60           errno = ENOMEM;       /* ? */
  61           return -1;
  62         }
  63       else
  64         {
  65           _hurd_id.gids[_hurd_id.ngroups++] = _hurd_id.gids[0];
  66           _hurd_id.gids[0] = gid;
  67         }
  68     }
  69
  70   _hurd_id.rgid = _hurd_id.gids[0];
  71
  72   if (err = auth_makeauth (_hurd_auth, &_hurd_id, &newauth))
  73     {
  74       _hurd_id_valid = 0;
  75       __mutex_unlock (&_hurd_idlock);
  76       return __hurd_fail (err);
  77     }
  78   else
  79     {
  80       int err = __setauth (newauth);
  81       __mach_port_deallocate (__mach_task_self (), newauth);
  82       return err;
  83     }
  84 }