usr/src/lib/libresolv2/common/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 /*! \file
  19  * \brief
  20  * dns.c --- this is the top-level accessor function for the dns
  21  */
  22
  23 #include "port_before.h"
  24
  25 #include <stdlib.h>
  26 #include <string.h>
  27 #include <errno.h>
  28
  29 #include <sys/types.h>
  30 #include <netinet/in.h>
  31 #include <arpa/nameser.h>
  32 #include <resolv.h>
  33
  34 #include <resolv.h>
  35
  36 #include <isc/memcluster.h>
  37 #include <irs.h>
  38
  39 #include "port_after.h"
  40
  41 #include "irs_p.h"
  42 #include "hesiod.h"
  43 #include "dns_p.h"
  44
  45 /* forward */
  46
  47 static void             dns_close(struct irs_acc *);
  48 static struct __res_state *     dns_res_get(struct irs_acc *);
  49 static void             dns_res_set(struct irs_acc *, struct __res_state *,
  50                                 void (*)(void *));
  51
  52 /* public */
  53
  54 struct irs_acc *
  55 irs_dns_acc(const char *options) {
  56         struct irs_acc *acc;
  57         struct dns_p *dns;
  58
  59         UNUSED(options);
  60
  61         if (!(acc = memget(sizeof *acc))) {
  62                 errno = ENOMEM;
  63                 return (NULL);
  64         }
  65         memset(acc, 0x5e, sizeof *acc);
  66         if (!(dns = memget(sizeof *dns))) {
  67                 errno = ENOMEM;
  68                 memput(acc, sizeof *acc);
  69                 return (NULL);
  70         }
  71         memset(dns, 0x5e, sizeof *dns);
  72         dns->res = NULL;
  73         dns->free_res = NULL;
  74         if (hesiod_init(&dns->hes_ctx) < 0) {
  75                 /*
  76                  * We allow the dns accessor class to initialize
  77                  * despite hesiod failing to initialize correctly,
  78                  * since dns host queries don't depend on hesiod.
  79                  */
  80                 dns->hes_ctx = NULL;
  81         }
  82         acc->private = dns;
  83 #ifdef WANT_IRS_GR
  84         acc->gr_map = irs_dns_gr;
  85 #else
  86         acc->gr_map = NULL;
  87 #endif
  88 #ifdef WANT_IRS_PW
  89         acc->pw_map = irs_dns_pw;
  90 #else
  91         acc->pw_map = NULL;
  92 #endif
  93         acc->sv_map = irs_dns_sv;
  94         acc->pr_map = irs_dns_pr;
  95         acc->ho_map = irs_dns_ho;
  96         acc->nw_map = irs_dns_nw;
  97         acc->ng_map = irs_nul_ng;
  98         acc->res_get = dns_res_get;
  99         acc->res_set = dns_res_set;
 100         acc->close = dns_close;
 101         return (acc);
 102 }
 103
 104 /* methods */
 105 static struct __res_state *
 106 dns_res_get(struct irs_acc *this) {
 107         struct dns_p *dns = (struct dns_p *)this->private;
 108
 109         if (dns->res == NULL) {
 110                 struct __res_state *res;
 111                 res = (struct __res_state *)malloc(sizeof *res);
 112                 if (res == NULL)
 113                         return (NULL);
 114                 memset(res, 0, sizeof *res);
 115                 dns_res_set(this, res, free);
 116         }
 117
 118         if ((dns->res->options & RES_INIT) == 0U &&
 119             res_ninit(dns->res) < 0)
 120                 return (NULL);
 121
 122         return (dns->res);
 123 }
 124
 125 static void
 126 dns_res_set(struct irs_acc *this, struct __res_state *res,
 127             void (*free_res)(void *)) {
 128         struct dns_p *dns = (struct dns_p *)this->private;
 129
 130         if (dns->res && dns->free_res) {
 131                 res_nclose(dns->res);
 132                 (*dns->free_res)(dns->res);
 133         }
 134         dns->res = res;
 135         dns->free_res = free_res;
 136 }
 137
 138 static void
 139 dns_close(struct irs_acc *this) {
 140         struct dns_p *dns;
 141
 142         dns = (struct dns_p *)this->private;
 143         if (dns->res && dns->free_res)
 144                 (*dns->free_res)(dns->res);
 145         if (dns->hes_ctx)
 146                 hesiod_end(dns->hes_ctx);
 147         memput(dns, sizeof *dns);
 148         memput(this, sizeof *this);
 149 }
 150