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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

 * 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 <machine/atomic.h>

#include <limits.h>

#include <stdlib.h>

#include <sys/types.h>

#include <netinet/in.h>

#include <arpa/nameser.h>

#include <resolv.h>

#include <bits/libc-lock.h>

#include "libc-symbols.h"

/* The following bit is copied from res_data.c (where it is #ifdef'ed

   out) since res_init() should go into libc.so but the rest of that

   file should not.  */

extern unsigned long long int __res_initstamp attribute_hidden;

/* We have atomic increment operations on 64-bit platforms.  */

#if __WORDSIZE == 64

# define atomicinclock(lock) (void) 0

# define atomicincunlock(lock) (void) 0

# define atomicinc(var) atomic_increment (&(var))

#else

__libc_lock_define_initialized (static, lock);

# define atomicinclock(lock) __libc_lock_lock (lock)

# define atomicincunlock(lock) __libc_lock_unlock (lock)

# define atomicinc(var) ++var

#endif

int

res_init(void) {

        extern int __res_vinit(res_state, int);

        /*

         * 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 = 4;

        if (!(_res.options & RES_INIT))

                _res.options = RES_DEFAULT;

        else if (_res.nscount > 0) {

                __res_nclose (&_res);   /* Close any VC sockets.  */

                int ns;

                for (ns = 0; ns < MAXNS; ns++) {

                        free (_res._u._ext.nsaddrs[ns]);

                        _res._u._ext.nsaddrs[ns] = NULL;

                }

        }

        /*

         * 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();

        atomicinclock (lock);

        /* Request all threads to re-initialize their resolver states,

           resolv.conf might have changed.  */

        atomicinc (__res_initstamp);

        atomicincunlock (lock);

        return (__res_vinit(&_res, 1));

}

/* Initialize resp if RES_INIT is not yet set or if res_init in some other

   thread requested re-initializing.  */

int

__res_maybe_init (res_state resp, int preinit)

{

        if (resp->options & RES_INIT) {

                if (__res_initstamp != resp->_u._ext.initstamp) {

                        if (resp->nscount > 0) {

                                __res_nclose (resp);

                                int ns;

                                for (ns = 0; ns < MAXNS; ns++) {

                                        free (resp->_u._ext.nsaddrs[ns]);

                                        resp->_u._ext.nsaddrs[ns] = NULL;

                                }

                                return __res_vinit (resp, 1);

                        }

                }

                return 0;

        } else if (preinit) {

                if (!resp->retrans)

                        resp->retrans = RES_TIMEOUT;

                if (!resp->retry)

                        resp->retry = 4;

                resp->options = RES_DEFAULT;

                if (!resp->id)

                        resp->id = res_randomid ();

                return __res_vinit (resp, 1);

        } else

                return __res_ninit (resp);

}

libc_hidden_def (__res_maybe_init)

/* 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__((section (".bss")));

#define USE___THREAD 1

#if USE___THREAD

#undef __resp

__thread struct __res_state *__resp = &_res;

extern __thread struct __res_state *__libc_resp

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

#endif

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

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

#if defined HAVE_ELF && defined SHARED && defined DO_VERSIONING

# include <shlib-compat.h>

compat_symbol (libc, _res, _res, GLIBC_2_0);

#endif

#include <shlib-compat.h>

#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