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dns.c revision 1.1.1.1.14.1 
      1 /*	$NetBSD: dns.c,v 1.1.1.1.14.1 2012/10/30 18:55:25 yamt Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
      5  * Copyright (c) 1996-1999 by Internet Software Consortium.
      6  *
      7  * Permission to use, copy, modify, and distribute this software for any
      8  * purpose with or without fee is hereby granted, provided that the above
      9  * copyright notice and this permission notice appear in all copies.
     10  *
     11  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
     12  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
     13  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
     14  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
     15  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
     16  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
     17  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
     18  */
     19 
     20 #if defined(LIBC_SCCS) && !defined(lint)
     21 static const char rcsid[] = "Id: dns.c,v 1.5 2006/03/09 23:57:56 marka Exp ";
     22 #endif
     23 
     24 /*! \file
     25  * \brief
     26  * dns.c --- this is the top-level accessor function for the dns
     27  */
     28 
     29 #include "port_before.h"
     30 
     31 #include <stdlib.h>
     32 #include <string.h>
     33 #include <errno.h>
     34 
     35 #include <sys/types.h>
     36 #include <netinet/in.h>
     37 #include <arpa/nameser.h>
     38 #include <resolv.h>
     39 
     40 #include <resolv.h>
     41 
     42 #include <isc/memcluster.h>
     43 #include <irs.h>
     44 
     45 #include "port_after.h"
     46 
     47 #include "irs_p.h"
     48 #include "hesiod.h"
     49 #include "dns_p.h"
     50 
     51 /* forward */
     52 
     53 static void		dns_close(struct irs_acc *);
     54 static struct __res_state *	dns_res_get(struct irs_acc *);
     55 static void		dns_res_set(struct irs_acc *, struct __res_state *,
     56 				void (*)(void *));
     57 
     58 /* public */
     59 
     60 struct irs_acc *
     61 irs_dns_acc(const char *options) {
     62 	struct irs_acc *acc;
     63 	struct dns_p *dns;
     64 
     65 	UNUSED(options);
     66 
     67 	if (!(acc = memget(sizeof *acc))) {
     68 		errno = ENOMEM;
     69 		return (NULL);
     70 	}
     71 	memset(acc, 0x5e, sizeof *acc);
     72 	if (!(dns = memget(sizeof *dns))) {
     73 		errno = ENOMEM;
     74 		memput(acc, sizeof *acc);
     75 		return (NULL);
     76 	}
     77 	memset(dns, 0x5e, sizeof *dns);
     78 	dns->res = NULL;
     79 	dns->free_res = NULL;
     80 	if (hesiod_init(&dns->hes_ctx) < 0) {
     81 		/*
     82 		 * We allow the dns accessor class to initialize
     83 		 * despite hesiod failing to initialize correctly,
     84 		 * since dns host queries don't depend on hesiod.
     85 		 */
     86 		dns->hes_ctx = NULL;
     87 	}
     88 	acc->private = dns;
     89 #ifdef WANT_IRS_GR
     90 	acc->gr_map = irs_dns_gr;
     91 #else
     92 	acc->gr_map = NULL;
     93 #endif
     94 #ifdef WANT_IRS_PW
     95 	acc->pw_map = irs_dns_pw;
     96 #else
     97 	acc->pw_map = NULL;
     98 #endif
     99 	acc->sv_map = irs_dns_sv;
    100 	acc->pr_map = irs_dns_pr;
    101 	acc->ho_map = irs_dns_ho;
    102 	acc->nw_map = irs_dns_nw;
    103 	acc->ng_map = irs_nul_ng;
    104 	acc->res_get = dns_res_get;
    105 	acc->res_set = dns_res_set;
    106 	acc->close = dns_close;
    107 	return (acc);
    108 }
    109 
    110 /* methods */
    111 static struct __res_state *
    112 dns_res_get(struct irs_acc *this) {
    113 	struct dns_p *dns = (struct dns_p *)this->private;
    114 
    115 	if (dns->res == NULL) {
    116 		struct __res_state *res;
    117 		res = (struct __res_state *)malloc(sizeof *res);
    118 		if (res == NULL)
    119 			return (NULL);
    120 		memset(res, 0, sizeof *res);
    121 		dns_res_set(this, res, free);
    122 	}
    123 
    124 	if ((dns->res->options & RES_INIT) == 0U &&
    125 	    res_ninit(dns->res) < 0)
    126 		return (NULL);
    127 
    128 	return (dns->res);
    129 }
    130 
    131 static void
    132 dns_res_set(struct irs_acc *this, struct __res_state *res,
    133 	    void (*free_res)(void *)) {
    134 	struct dns_p *dns = (struct dns_p *)this->private;
    135 
    136 	if (dns->res && dns->free_res) {
    137 		res_nclose(dns->res);
    138 		(*dns->free_res)(dns->res);
    139 	}
    140 	dns->res = res;
    141 	dns->free_res = free_res;
    142 }
    143 
    144 static void
    145 dns_close(struct irs_acc *this) {
    146 	struct dns_p *dns;
    147 
    148 	dns = (struct dns_p *)this->private;
    149 	if (dns->res && dns->free_res)
    150 		(*dns->free_res)(dns->res);
    151 	if (dns->hes_ctx)
    152 		hesiod_end(dns->hes_ctx);
    153 	memput(dns, sizeof *dns);
    154 	memput(this, sizeof *this);
    155 }
    156 
    157