sysdeps/mach/hurd/setregid.c

   1 /* Copyright (C) 1993-2024 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 Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the 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    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18 #include <errno.h>
  19 #include <sys/types.h>
  20 #include <unistd.h>
  21 #include <hurd.h>
  22 #include <hurd/id.h>
  23 #include <string.h>
  24
  25 int
  26 __setregid (gid_t rgid, gid_t egid)
  27 {
  28   auth_t newauth;
  29   error_t err;
  30
  31 retry:
  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 RGID as the real gid,
  39          and EGID as the first element in the list of effective gids.  */
  40
  41       gid_t *newgen, *newaux;
  42       size_t ngen, naux;
  43
  44       newgen = _hurd_id.gen.gids;
  45       ngen = _hurd_id.gen.ngids;
  46       if (egid != -1)
  47         {
  48           if (_hurd_id.gen.ngids == 0)
  49             {
  50               /* No effective gids now.  The new set will be just GID.  */
  51               newgen = &egid;
  52               ngen = 1;
  53             }
  54           else
  55             {
  56               _hurd_id.gen.gids[0] = egid;
  57               _hurd_id.valid = 0;
  58             }
  59         }
  60
  61       newaux = _hurd_id.aux.gids;
  62       naux = _hurd_id.aux.ngids;
  63       if (rgid != -1)
  64         {
  65           if (_hurd_id.aux.ngids == 0)
  66             {
  67               newaux = &rgid;
  68               naux = 1;
  69             }
  70           else
  71             {
  72               _hurd_id.aux.gids[0] = rgid;
  73               _hurd_id.valid = 0;
  74             }
  75         }
  76
  77       err = __USEPORT (AUTH, __auth_makeauth
  78                        (port, NULL, MACH_MSG_TYPE_COPY_SEND, 0,
  79                         _hurd_id.gen.uids, _hurd_id.gen.nuids,
  80                         _hurd_id.aux.uids, _hurd_id.aux.nuids,
  81                         newgen, ngen, newaux, naux,
  82                         &newauth));
  83     }
  84   __mutex_unlock (&_hurd_id.lock);
  85   HURD_CRITICAL_END;
  86   if (err == EINTR)
  87     /* Got a signal while inside an RPC of the critical section, retry again */
  88     goto retry;
  89
  90   if (err)
  91     return __hurd_fail (err);
  92
  93   /* Install the new handle and reauthenticate everything.  */
  94   err = __setauth (newauth);
  95   __mach_port_deallocate (__mach_task_self (), newauth);
  96   return err;
  97 }
  98
  99 weak_alias (__setregid, setregid)