contrib/bind-9.2.4rc7/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 1.1.2.2 2004/03/17 00:40:11 marka Exp $";
  20 #endif
  21
  22 /*
  23  * dns.c --- this is the top-level accessor function for the dns
  24  */
  25
  26 #include "port_before.h"
  27
  28 #include <stdlib.h>
  29 #include <string.h>
  30 #include <errno.h>
  31
  32 #include <sys/types.h>
  33 #include <netinet/in.h>
  34 #include <arpa/nameser.h>
  35 #include <resolv.h>
  36
  37 #include <resolv.h>
  38
  39 #include <isc/memcluster.h>
  40 #include <irs.h>
  41
  42 #include "port_after.h"
  43
  44 #include "irs_p.h"
  45 #include "hesiod.h"
  46 #include "dns_p.h"
  47
  48 /* forward */
  49
  50 static void             dns_close(struct irs_acc *);
  51 static struct __res_state *     dns_res_get(struct irs_acc *);
  52 static void             dns_res_set(struct irs_acc *, struct __res_state *,
  53                                 void (*)(void *));
  54
  55 /* public */
  56
  57 struct irs_acc *
  58 irs_dns_acc(const char *options) {
  59         struct irs_acc *acc;
  60         struct dns_p *dns;
  61
  62         UNUSED(options);
  63
  64         if (!(acc = memget(sizeof *acc))) {
  65                 errno = ENOMEM;
  66                 return (NULL);
  67         }
  68         memset(acc, 0x5e, sizeof *acc);
  69         if (!(dns = memget(sizeof *dns))) {
  70                 errno = ENOMEM;
  71                 memput(acc, sizeof *acc);
  72                 return (NULL);
  73         }
  74         memset(dns, 0x5e, sizeof *dns);
  75         dns->res = NULL;
  76         dns->free_res = NULL;
  77         if (hesiod_init(&dns->hes_ctx) < 0) {
  78                 /*
  79                  * We allow the dns accessor class to initialize
  80                  * despite hesiod failing to initialize correctly,
  81                  * since dns host queries don't depend on hesiod.
  82                  */
  83                 dns->hes_ctx = NULL;
  84         }
  85         acc->private = dns;
  86 #ifdef WANT_IRS_GR
  87         acc->gr_map = irs_dns_gr;
  88 #else
  89         acc->gr_map = NULL;
  90 #endif
  91 #ifdef WANT_IRS_PW
  92         acc->pw_map = irs_dns_pw;
  93 #else
  94         acc->pw_map = NULL;
  95 #endif
  96         acc->sv_map = irs_dns_sv;
  97         acc->pr_map = irs_dns_pr;
  98         acc->ho_map = irs_dns_ho;
  99         acc->nw_map = irs_dns_nw;
 100         acc->ng_map = irs_nul_ng;
 101         acc->res_get = dns_res_get;
 102         acc->res_set = dns_res_set;
 103         acc->close = dns_close;
 104         return (acc);
 105 }
 106
 107 /* methods */
 108 static struct __res_state *
 109 dns_res_get(struct irs_acc *this) {
 110         struct dns_p *dns = (struct dns_p *)this->private;
 111
 112         if (dns->res == NULL) {
 113                 struct __res_state *res;
 114                 res = (struct __res_state *)malloc(sizeof *res);
 115                 if (res == NULL)
 116                         return (NULL);
 117                 memset(dns->res, 0, sizeof *dns->res);
 118                 dns_res_set(this, res, free);
 119         }
 120
 121         if ((dns->res->options & RES_INIT) == 0U &&
 122             res_ninit(dns->res) < 0)
 123                 return (NULL);
 124
 125         return (dns->res);
 126 }
 127
 128 static void
 129 dns_res_set(struct irs_acc *this, struct __res_state *res,
 130             void (*free_res)(void *)) {
 131         struct dns_p *dns = (struct dns_p *)this->private;
 132
 133         if (dns->res && dns->free_res) {
 134                 res_nclose(dns->res);
 135                 (*dns->free_res)(dns->res);
 136         }
 137         dns->res = res;
 138         dns->free_res = free_res;
 139 }
 140
 141 static void
 142 dns_close(struct irs_acc *this) {
 143         struct dns_p *dns;
 144
 145         dns = (struct dns_p *)this->private;
 146         if (dns->res && dns->free_res)
 147                 (*dns->free_res)(dns->res);
 148         if (dns->hes_ctx)
 149                 hesiod_end(dns->hes_ctx);
 150         memput(dns, sizeof *dns);
 151         memput(this, sizeof *this);
 152 }
 153