dns.c revision 9525b14bcdeb5b5f6f95ab27c2f48f18bd2ec829
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)
19static 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
51static void		dns_close(struct irs_acc *);
52static struct __res_state *	dns_res_get(struct irs_acc *);
53static void		dns_res_set(struct irs_acc *, struct __res_state *,
54				void (*)(void *));
55
56/* public */
57
58struct irs_acc *
59irs_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 */
109static struct __res_state *
110dns_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
129static void
130dns_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
142static void
143dns_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
155