/* Definitions related to res_init linked into libc instead of libresolv.
Copyright (C) 1995-2018 Free Software Foundation, Inc.
This file is part of the GNU C Library.
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modify it under the terms of the GNU Lesser General Public
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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* Copyright (c) 1995-1999 by Internet Software Consortium.
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
* THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
* ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
* CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
* DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
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/* These three fields used to be statically initialized. This made
it hard to use this code in a shared library. It is necessary,
now that we're doing dynamic initialization here, that we
preserve the old semantics: if an application modifies one of
these three fields of _res before res_init is called,
res_init will not alter them. Of course, if an application is
setting them to _zero_ before calling res_init, hoping to
override what used to be the static default, we can't detect it
and unexpected results will follow. Zero for any of these fields
would make no sense, so one can safely assume that the
applications were already getting unexpected results.
_res.options is tricky since some apps were known to diddle the
bits before res_init was first called. We can't replicate that
semantic with dynamic initialization (they may have turned bits
off that are set in RES_DEFAULT). Our solution is to declare
such applications "broken". They could fool us by setting
RES_INIT but none do (yet). */
_res.retrans = RES_TIMEOUT;
_res.retry = RES_DFLRETRY;
if (!(_res.options & RES_INIT))
_res.options = RES_DEFAULT;
else if (_res.nscount > 0)
__res_iclose (&_res, true); /* Close any VC sockets. */
/* This one used to initialize implicitly to zero, so unless the app
has set it to something in particular, we can randomize it *
_res.id = res_randomid ();
return __res_vinit (&_res, 1);
/* This needs to be after the use of _res in res_init, above. */
/* The resolver state for use by single-threaded programs.
This differs from plain `struct __res_state _res;' in that it doesn't
create a common definition, but a plain symbol that resides in .bss,
which can have an alias. */
struct __res_state _res __attribute__ ((nocommon));
__thread struct __res_state *__resp = &_res;
extern __thread struct __res_state *__libc_resp
__attribute__ ((alias ("__resp"))) attribute_hidden;
/* We declare this with compat_symbol so that it's not
visible at link time. Programs must use the accessor functions. */
compat_symbol (libc, _res, _res, GLIBC_2_0);
#if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_2)
# undef res_init
extern int __res_init_weak (void);
strong_alias (__res_init, __res_init_weak);
compat_symbol (libc, __res_init_weak, res_init, GLIBC_2_0);