contrib/bind-9.5.2/lib/bind/irs/dns.c

   1 /*
   2  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
   3  * Copyright (c) 1996-1999 by Internet Software Consortium.
   4  *
   5  * Permission to use, copy, modify, and distribute this software for any
   6  * purpose with or without fee is hereby granted, provided that the above
   7  * copyright notice and this permission notice appear in all copies.
   8  *
   9  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
  10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  11  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
  12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
  15  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  16  */
  17
  18 #if defined(LIBC_SCCS) && !defined(lint)
  19 static const char rcsid[] = "$Id: dns.c,v 1.5 2006/03/09 23:57:56 marka Exp $";
  20 #endif
  21
  22 /*! \file
  23  * \brief
  24  * dns.c --- this is the top-level accessor function for the dns
  25  */
  26
  27 #include "port_before.h"
  28
  29 #include <stdlib.h>
  30 #include <string.h>
  31 #include <errno.h>
  32
  33 #include <sys/types.h>
  34 #include <netinet/in.h>
  35 #include <arpa/nameser.h>
  36 #include <resolv.h>
  37
  38 #include <resolv.h>
  39
  40 #include <isc/memcluster.h>
  41 #include <irs.h>
  42
  43 #include "port_after.h"
  44
  45 #include "irs_p.h"
  46 #include "hesiod.h"
  47 #include "dns_p.h"
  48
  49 /* forward */
  50
  51 static void             dns_close(struct irs_acc *);
  52 static struct __res_state *     dns_res_get(struct irs_acc *);
  53 static void             dns_res_set(struct irs_acc *, struct __res_state *,
  54                                 void (*)(void *));
  55
  56 /* public */
  57
  58 struct irs_acc *
  59 irs_dns_acc(const char *options) {
  60         struct irs_acc *acc;
  61         struct dns_p *dns;
  62
  63         UNUSED(options);
  64
  65         if (!(acc = memget(sizeof *acc))) {
  66                 errno = ENOMEM;
  67                 return (NULL);
  68         }
  69         memset(acc, 0x5e, sizeof *acc);
  70         if (!(dns = memget(sizeof *dns))) {
  71                 errno = ENOMEM;
  72                 memput(acc, sizeof *acc);
  73                 return (NULL);
  74         }
  75         memset(dns, 0x5e, sizeof *dns);
  76         dns->res = NULL;
  77         dns->free_res = NULL;
  78         if (hesiod_init(&dns->hes_ctx) < 0) {
  79                 /*
  80                  * We allow the dns accessor class to initialize
  81                  * despite hesiod failing to initialize correctly,
  82                  * since dns host queries don't depend on hesiod.
  83                  */
  84                 dns->hes_ctx = NULL;
  85         }
  86         acc->private = dns;
  87 #ifdef WANT_IRS_GR
  88         acc->gr_map = irs_dns_gr;
  89 #else
  90         acc->gr_map = NULL;
  91 #endif
  92 #ifdef WANT_IRS_PW
  93         acc->pw_map = irs_dns_pw;
  94 #else
  95         acc->pw_map = NULL;
  96 #endif
  97         acc->sv_map = irs_dns_sv;
  98         acc->pr_map = irs_dns_pr;
  99         acc->ho_map = irs_dns_ho;
 100         acc->nw_map = irs_dns_nw;
 101         acc->ng_map = irs_nul_ng;
 102         acc->res_get = dns_res_get;
 103         acc->res_set = dns_res_set;
 104         acc->close = dns_close;
 105         return (acc);
 106 }
 107
 108 /* methods */
 109 static struct __res_state *
 110 dns_res_get(struct irs_acc *this) {
 111         struct dns_p *dns = (struct dns_p *)this->private;
 112
 113         if (dns->res == NULL) {
 114                 struct __res_state *res;
 115                 res = (struct __res_state *)malloc(sizeof *res);
 116                 if (res == NULL)
 117                         return (NULL);
 118                 memset(res, 0, sizeof *res);
 119                 dns_res_set(this, res, free);
 120         }
 121
 122         if ((dns->res->options & RES_INIT) == 0U &&
 123             res_ninit(dns->res) < 0)
 124                 return (NULL);
 125
 126         return (dns->res);
 127 }
 128
 129 static void
 130 dns_res_set(struct irs_acc *this, struct __res_state *res,
 131             void (*free_res)(void *)) {
 132         struct dns_p *dns = (struct dns_p *)this->private;
 133
 134         if (dns->res && dns->free_res) {
 135                 res_nclose(dns->res);
 136                 (*dns->free_res)(dns->res);
 137         }
 138         dns->res = res;
 139         dns->free_res = free_res;
 140 }
 141
 142 static void
 143 dns_close(struct irs_acc *this) {
 144         struct dns_p *dns;
 145
 146         dns = (struct dns_p *)this->private;
 147         if (dns->res && dns->free_res)
 148                 (*dns->free_res)(dns->res);
 149         if (dns->hes_ctx)
 150                 hesiod_end(dns->hes_ctx);
 151         memput(dns, sizeof *dns);
 152         memput(this, sizeof *this);
 153 }
 154