/* 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.

   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

   <http://www.gnu.org/licenses/>.  */

/*

 * 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

 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS

 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS

 * SOFTWARE.

 */

#include <atomic.h>

#include <limits.h>

#include <sys/types.h>

#include <netinet/in.h>

#include <arpa/nameser.h>

#include <resolv.h>

#include <libc-lock.h>

#include <resolv-internal.h>

int

res_init (void)

{

  /* 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).  */

  if (!_res.retrans)

    _res.retrans = RES_TIMEOUT;

  if (!_res.retry)

    _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 *

     now.  */

  if (!_res.id)

    _res.id = res_randomid ();

  return __res_vinit (&_res, 1);

}

/* This needs to be after the use of _res in res_init, above.  */

#undef _res

/* 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));

#undef __resp

__thread struct __res_state *__resp = &_res;

extern __thread struct __res_state *__libc_resp

  __attribute__ ((alias ("__resp"))) attribute_hidden;

#include <shlib-compat.h>

/* We declare this with compat_symbol so that it's not

   visible at link time.  Programs must use the accessor functions.  */

#ifdef SHARED

compat_symbol (libc, _res, _res, GLIBC_2_0);

#endif

#if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_2)

# undef res_init

extern int __res_init_weak (void);

weak_extern (__res_init_weak);

strong_alias (__res_init, __res_init_weak);

compat_symbol (libc, __res_init_weak, res_init, GLIBC_2_0);

#endif