lib/libc/resolv/res_state.c

   1 /*-
   2  * Copyright (c) 2006 The FreeBSD Project. All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. Redistributions in binary form must reproduce the above copyright
  10  *    notice, this list of conditions and the following disclaimer in the
  11  *    documentation and/or other materials provided with the distribution.
  12  *
  13  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  14  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  16  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  17  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  18  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  19  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  20  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  21  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  22  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  23  * SUCH DAMAGE.
  24  *
  25  * $FreeBSD: src/lib/libc/resolv/res_state.c,v 1.3 2006/05/21 11:29:26 ume Exp $
  26  */
  27
  28 #include <sys/types.h>
  29 #include <netinet/in.h>
  30 #include <arpa/nameser.h>
  31 #include <resolv.h>
  32 #include <stdlib.h>
  33
  34 #include "namespace.h"
  35 #include "reentrant.h"
  36 #include "un-namespace.h"
  37
  38 #undef _res
  39
  40 struct __res_state _res;
  41
  42 static thread_key_t res_key;
  43 static once_t res_init_once = ONCE_INITIALIZER;
  44 static int res_thr_keycreated = 0;
  45
  46 static void
  47 free_res(void *ptr)
  48 {
  49         res_state statp = ptr;
  50
  51         if (statp->_u._ext.ext != NULL)
  52                 res_ndestroy(statp);
  53         free(statp);
  54 }
  55
  56 static void
  57 res_keycreate(void)
  58 {
  59         res_thr_keycreated = thr_keycreate(&res_key, free_res) == 0;
  60 }
  61
  62 res_state
  63 __res_state(void)
  64 {
  65         res_state statp;
  66
  67         if (thr_main() != 0)
  68                 return (&_res);
  69
  70         if (thr_once(&res_init_once, res_keycreate) != 0 ||
  71             !res_thr_keycreated)
  72                 return (&_res);
  73
  74         statp = thr_getspecific(res_key);
  75         if (statp != NULL)
  76                 return (statp);
  77         statp = calloc(1, sizeof(*statp));
  78         if (statp == NULL)
  79                 return (&_res);
  80 #ifdef __BIND_RES_TEXT
  81         statp->options = RES_TIMEOUT;                   /* Motorola, et al. */
  82 #endif
  83         if (thr_setspecific(res_key, statp) == 0)
  84                 return (statp);
  85         free(statp);
  86         return (&_res);
  87 }