+/* Definitions related to res_init linked into libc instead of libresolv.
+ Copyright (C) 1995-2019 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.
*
* 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>
-#undef _res
+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.
-#include <tls.h>
+ _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. */
-#if USE_TLS && HAVE___THREAD
-/* With __thread support, this per-thread variable is used in all cases. */
-__thread struct __res_state _res;
-#else
-/* The resolver state for use by single-threaded programs. */
-struct __res_state _res;
-#endif
+ /* 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 ();
-/* This function is used to access the resolver state in
- single-threaded programs. */
-struct __res_state *
-weak_const_function
-__res_state (void)
-{
- return &_res;
+ return __res_vinit (&_res, 1);
}
\f
+/* This needs to be after the use of _res in res_init, above. */
+#undef _res
-/* 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. */
-
-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;
-
- /*
- * 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();
+/* 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));
- return (__res_vinit(&_res, 1));
-}
-\f
+#undef __resp
+__thread struct __res_state *__resp = &_res;
+extern __thread struct __res_state *__libc_resp
+ __attribute__ ((alias ("__resp"))) attribute_hidden;
#include <shlib-compat.h>
-#if SHLIB_COMPAT(libc, GLIBC_2_0, GLIBC_2_2)
+/* 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
-strong_alias (__res_init, __res_init_weak);
+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
projects / thirdparty / glibc.git / blobdiff