102 lines
3.7 KiB
C
102 lines
3.7 KiB
C
/*
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* Copyright (c) 1995-1999 by Internet Software Consortium.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
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* ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
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* CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
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* DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
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* PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
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* ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
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* SOFTWARE.
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*/
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#include <sys/types.h>
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#include <netinet/in.h>
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#include <arpa/nameser.h>
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#include <resolv.h>
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/* The following bit is copied from res_data.c (where it is #ifdef'ed
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out) since res_init() should go into libc.so but the rest of that
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file should not. */
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int
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res_init(void) {
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extern int __res_vinit(res_state, int);
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/*
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* These three fields used to be statically initialized. This made
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* it hard to use this code in a shared library. It is necessary,
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* now that we're doing dynamic initialization here, that we preserve
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* the old semantics: if an application modifies one of these three
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* fields of _res before res_init() is called, res_init() will not
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* alter them. Of course, if an application is setting them to
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* _zero_ before calling res_init(), hoping to override what used
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* to be the static default, we can't detect it and unexpected results
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* will follow. Zero for any of these fields would make no sense,
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* so one can safely assume that the applications were already getting
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* unexpected results.
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*
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* _res.options is tricky since some apps were known to diddle the bits
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* before res_init() was first called. We can't replicate that semantic
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* with dynamic initialization (they may have turned bits off that are
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* set in RES_DEFAULT). Our solution is to declare such applications
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* "broken". They could fool us by setting RES_INIT but none do (yet).
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*/
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if (!_res.retrans)
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_res.retrans = RES_TIMEOUT;
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if (!_res.retry)
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_res.retry = 4;
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if (!(_res.options & RES_INIT))
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_res.options = RES_DEFAULT;
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/*
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* This one used to initialize implicitly to zero, so unless the app
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* has set it to something in particular, we can randomize it now.
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*/
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if (!_res.id)
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_res.id = res_randomid();
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return (__res_vinit(&_res, 1));
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}
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/* This needs to be after the use of _res in res_init, above. */
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#undef _res
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/* The resolver state for use by single-threaded programs.
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This differs from plain `struct __res_state _res;' in that it doesn't
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create a common definition, but a plain symbol that resides in .bss,
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which can have an alias. */
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struct __res_state _res __attribute__((section (".bss")));
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#include <tls.h>
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#if USE___THREAD
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#undef __resp
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__thread struct __res_state *__resp = &_res;
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extern __thread struct __res_state *__libc_resp
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__attribute__ ((alias ("__resp"))) attribute_hidden;
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#endif
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/* We declare this with compat_symbol so that it's not
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visible at link time. Programs must use the accessor functions. */
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#if defined HAVE_ELF && defined SHARED && defined DO_VERSIONING
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# include <shlib-compat.h>
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compat_symbol (libc, _res, _res, GLIBC_2_0);
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#endif
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#include <shlib-compat.h>
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#if SHLIB_COMPAT(libc, GLIBC_2_0, GLIBC_2_2)
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# undef res_init
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extern int __res_init_weak (void);
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weak_extern (__res_init_weak);
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strong_alias (__res_init, __res_init_weak);
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compat_symbol (libc, __res_init_weak, res_init, GLIBC_2_0);
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#endif
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