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/* Copyright (C) 1991-2024 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
<https://www.gnu.org/licenses/>. */
#include <errno.h>
#include <unistd.h>
#include <sys/types.h>
#include <hurd.h>
#include <hurd/id.h>
#include <string.h>
/* Set the group ID of the calling process to UID.
If the calling process is the super-user, the real
and effective group IDs, and the saved set-group-ID to UID;
if not, the effective group ID is set to GID. */
int
__setgid (gid_t gid)
{
auth_t newauth;
error_t err;
retry:
HURD_CRITICAL_BEGIN;
__mutex_lock (&_hurd_id.lock);
err = _hurd_check_ids ();
if (!err)
{
/* Make a new auth handle which has GID as the real gid,
and as the first element in the list of effective gids. */
gid_t *newgen, *newaux, auxbuf[2];
size_t ngen, naux;
if (_hurd_id.gen.ngids == 0)
{
/* No effective gids now. The new set will be just GID. */
newgen = &gid;
ngen = 1;
}
else
{
_hurd_id.gen.gids[0] = gid;
_hurd_id.valid = 0;
newgen = _hurd_id.gen.gids;
ngen = _hurd_id.gen.ngids;
}
newaux = _hurd_id.aux.gids;
naux = _hurd_id.aux.ngids;
if (_hurd_id.gen.nuids > 0 && _hurd_id.gen.uids[0] == 0)
{
/* We are root; set the real and saved IDs too. */
_hurd_id.valid = 0;
if (_hurd_id.aux.ngids < 2)
{
newaux = auxbuf;
naux = 2;
}
newaux[0] = newaux[1] = gid;
}
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 == EINTR)
/* Got a signal while inside an RPC of the critical section, retry again */
goto retry;
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 (__setgid, setgid)
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