diff options
Diffstat (limited to 'resolv/res_libc.c')
| -rw-r--r-- | resolv/res_libc.c | 153 |
1 files changed, 86 insertions, 67 deletions
diff --git a/resolv/res_libc.c b/resolv/res_libc.c index f322e8ce3f..3d7b4f72d0 100644 --- a/resolv/res_libc.c +++ b/resolv/res_libc.c @@ -1,3 +1,21 @@ +/* Definitions related to res_init linked into libc instead of libresolv. + Copyright (C) 1995-2017 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. * @@ -15,9 +33,6 @@ * SOFTWARE. */ -/* This file contains the definitions related to res_init which are - linked into libc instead of libresolv. */ - #include <atomic.h> #include <limits.h> #include <sys/types.h> @@ -40,74 +55,78 @@ __libc_lock_define_initialized (static, lock); #endif 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(); - - 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)); +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 (); + + 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. */ +/* Initialize *RESP if RES_INIT is not yet set in RESP->options, 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_iclose (resp, true); - return __res_vinit (resp, 1); - } - return 0; - } else if (preinit) { - if (!resp->retrans) - resp->retrans = RES_TIMEOUT; - if (!resp->retry) - resp->retry = RES_DFLRETRY; - resp->options = RES_DEFAULT; - if (!resp->id) - resp->id = res_randomid (); - return __res_vinit (resp, 1); - } else - return __res_ninit (resp); + if (resp->options & RES_INIT) + { + if (__res_initstamp != resp->_u._ext.initstamp) + { + if (resp->nscount > 0) + __res_iclose (resp, true); + return __res_vinit (resp, 1); + } + return 0; + } + else if (preinit) + { + if (!resp->retrans) + resp->retrans = RES_TIMEOUT; + if (!resp->retry) + resp->retry = RES_DFLRETRY; + 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) @@ -133,7 +152,7 @@ extern __thread struct __res_state *__libc_resp compat_symbol (libc, _res, _res, GLIBC_2_0); #endif -#if SHLIB_COMPAT(libc, GLIBC_2_0, GLIBC_2_2) +#if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_2) # undef res_init extern int __res_init_weak (void); weak_extern (__res_init_weak); |