sysdeps/mach/hurd/setresgid.c

   1 /* setresgid -- set real group ID, effective group ID, and saved-set group ID
   2    Copyright (C) 2002-2016 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <errno.h>
  20 #include <unistd.h>
  21 #include <hurd.h>
  22 #include <hurd/id.h>
  23
  24 /* Set the real group ID, effective group ID, and saved-set group ID,
  25    of the calling process to RGID, EGID, and SGID, respectively.  */
  26 int
  27 __setresgid (gid_t rgid, gid_t egid, gid_t sgid)
  28 {
  29   auth_t newauth;
  30   error_t err;
  31
  32   HURD_CRITICAL_BEGIN;
  33   __mutex_lock (&_hurd_id.lock);
  34   err = _hurd_check_ids ();
  35
  36   if (!err)
  37     {
  38       /* Make a new auth handle which has EGID as the first element in the
  39          list of effective gids.  */
  40
  41       uid_t *newgen, *newaux;
  42       uid_t auxs[2] = { rgid, sgid };
  43       size_t ngen, naux;
  44
  45       newgen = _hurd_id.gen.gids;
  46       ngen = _hurd_id.gen.ngids;
  47       if (egid != -1)
  48         {
  49           if (_hurd_id.gen.ngids == 0)
  50             {
  51               /* No effective gids now.  The new set will be just UID.  */
  52               newgen = &egid;
  53               ngen = 1;
  54             }
  55           else
  56             {
  57               _hurd_id.gen.gids[0] = egid;
  58               _hurd_id.valid = 0;
  59             }
  60         }
  61
  62       newaux = _hurd_id.aux.gids;
  63       naux = _hurd_id.aux.ngids;
  64       if (rgid != -1)
  65         {
  66           if (_hurd_id.aux.ngids == 0)
  67             {
  68               newaux = &rgid;
  69               naux = 1;
  70             }
  71           else
  72             {
  73               _hurd_id.aux.gids[0] = rgid;
  74               _hurd_id.valid = 0;
  75             }
  76         }
  77
  78       if (sgid != -1)
  79         {
  80           if (rgid == -1)
  81             {
  82               if (_hurd_id.aux.ngids >= 1)
  83                 auxs[0] = _hurd_id.aux.gids[0];
  84               else if (_hurd_id.gen.ngids >= 1)
  85                 auxs[0] = _hurd_id.gen.gids[0];
  86               else
  87                 /* Not even an effective GID.
  88                    Fall back to the only GID we have. */
  89                 auxs[0] = sgid;
  90             }
  91           if (_hurd_id.aux.ngids <= 1)
  92             {
  93               /* No saved gids now.  The new set will be just UID.  */
  94               newaux = auxs;
  95               naux = 2;
  96             }
  97           else
  98             {
  99               _hurd_id.aux.gids[1] = sgid;
 100               _hurd_id.valid = 0;
 101             }
 102         }
 103
 104       err = __USEPORT (AUTH, __auth_makeauth
 105                        (port, NULL, MACH_MSG_TYPE_COPY_SEND, 0,
 106                         _hurd_id.gen.uids, _hurd_id.gen.nuids,
 107                         _hurd_id.aux.uids, _hurd_id.aux.nuids,
 108                         newgen, ngen, newaux, naux,
 109                         &newauth));
 110     }
 111   __mutex_unlock (&_hurd_id.lock);
 112   HURD_CRITICAL_END;
 113
 114   if (err)
 115     return __hurd_fail (err);
 116
 117   /* Install the new handle and reauthenticate everything.  */
 118   err = __setauth (newauth);
 119   __mach_port_deallocate (__mach_task_self (), newauth);
 120   return err;
 121 }
 122 libc_hidden_def (__setresgid)
 123 weak_alias (__setresgid, setresgid)