/contrib/bind9/bin/named/lwsearch.c

  1/*
  2 * Copyright (C) 2004, 2005, 2007  Internet Systems Consortium, Inc. ("ISC")
  3 * Copyright (C) 2000, 2001  Internet Software Consortium.
  4 *
  5 * Permission to use, copy, modify, and/or 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 WITH
 10 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 11 * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
 12 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
 13 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
 14 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 15 * PERFORMANCE OF THIS SOFTWARE.
 16 */
 17
 18/* $Id: lwsearch.c,v 1.13 2007/06/19 23:46:59 tbox Exp $ */
 19
 20/*! \file */
 21
 22#include <config.h>
 23
 24#include <isc/magic.h>
 25#include <isc/mem.h>
 26#include <isc/mutex.h>
 27#include <isc/result.h>
 28#include <isc/types.h>
 29#include <isc/util.h>
 30
 31#include <dns/name.h>
 32#include <dns/types.h>
 33
 34#include <named/lwsearch.h>
 35#include <named/types.h>
 36
 37#define LWSEARCHLIST_MAGIC		ISC_MAGIC('L', 'W', 'S', 'L')
 38#define VALID_LWSEARCHLIST(l)		ISC_MAGIC_VALID(l, LWSEARCHLIST_MAGIC)
 39
 40isc_result_t
 41ns_lwsearchlist_create(isc_mem_t *mctx, ns_lwsearchlist_t **listp) {
 42	ns_lwsearchlist_t *list;
 43	isc_result_t result;
 44
 45	REQUIRE(mctx != NULL);
 46	REQUIRE(listp != NULL && *listp == NULL);
 47
 48	list = isc_mem_get(mctx, sizeof(ns_lwsearchlist_t));
 49	if (list == NULL)
 50		return (ISC_R_NOMEMORY);
 51	
 52	result = isc_mutex_init(&list->lock);
 53	if (result != ISC_R_SUCCESS) {
 54		isc_mem_put(mctx, list, sizeof(ns_lwsearchlist_t));
 55		return (result);
 56	}
 57	list->mctx = NULL;
 58	isc_mem_attach(mctx, &list->mctx);
 59	list->refs = 1;
 60	ISC_LIST_INIT(list->names);
 61	list->magic = LWSEARCHLIST_MAGIC;
 62
 63	*listp = list;
 64	return (ISC_R_SUCCESS);
 65}
 66
 67void
 68ns_lwsearchlist_attach(ns_lwsearchlist_t *source, ns_lwsearchlist_t **target) {
 69	REQUIRE(VALID_LWSEARCHLIST(source));
 70	REQUIRE(target != NULL && *target == NULL);
 71
 72	LOCK(&source->lock);
 73	INSIST(source->refs > 0);
 74	source->refs++;
 75	INSIST(source->refs != 0);
 76	UNLOCK(&source->lock);
 77
 78	*target = source;
 79}
 80
 81void
 82ns_lwsearchlist_detach(ns_lwsearchlist_t **listp) {
 83	ns_lwsearchlist_t *list;
 84	isc_mem_t *mctx;
 85
 86	REQUIRE(listp != NULL);
 87	list = *listp;
 88	REQUIRE(VALID_LWSEARCHLIST(list));
 89
 90	LOCK(&list->lock);
 91	INSIST(list->refs > 0);
 92	list->refs--;
 93	UNLOCK(&list->lock);
 94
 95	*listp = NULL;
 96	if (list->refs != 0)
 97		return;
 98
 99	mctx = list->mctx;
100	while (!ISC_LIST_EMPTY(list->names)) {
101		dns_name_t *name = ISC_LIST_HEAD(list->names);
102		ISC_LIST_UNLINK(list->names, name, link);
103		dns_name_free(name, list->mctx);
104		isc_mem_put(list->mctx, name, sizeof(dns_name_t));
105	}
106	list->magic = 0;
107	isc_mem_put(mctx, list, sizeof(ns_lwsearchlist_t));
108	isc_mem_detach(&mctx);
109}
110
111isc_result_t
112ns_lwsearchlist_append(ns_lwsearchlist_t *list, dns_name_t *name) {
113	dns_name_t *newname;
114	isc_result_t result;
115
116	REQUIRE(VALID_LWSEARCHLIST(list));
117	REQUIRE(name != NULL);
118
119	newname = isc_mem_get(list->mctx, sizeof(dns_name_t));
120	if (newname == NULL)
121		return (ISC_R_NOMEMORY);
122	dns_name_init(newname, NULL);
123	result = dns_name_dup(name, list->mctx, newname);
124	if (result != ISC_R_SUCCESS) {
125		isc_mem_put(list->mctx, newname, sizeof(dns_name_t));
126		return (result);
127	}
128	ISC_LINK_INIT(newname, link);
129	ISC_LIST_APPEND(list->names, newname, link);
130	return (ISC_R_SUCCESS);
131}
132
133void
134ns_lwsearchctx_init(ns_lwsearchctx_t *sctx, ns_lwsearchlist_t *list,
135		    dns_name_t *name, unsigned int ndots)
136{
137	INSIST(sctx != NULL);
138	sctx->relname = name;
139	sctx->searchname = NULL;
140	sctx->doneexact = ISC_FALSE;
141	sctx->exactfirst = ISC_FALSE;
142	sctx->ndots = ndots;
143	if (dns_name_isabsolute(name) || list == NULL) {
144		sctx->list = NULL;
145		return;
146	}
147	sctx->list = list;
148	sctx->searchname = ISC_LIST_HEAD(sctx->list->names);
149	if (dns_name_countlabels(name) > ndots)
150		sctx->exactfirst = ISC_TRUE;
151}
152
153void
154ns_lwsearchctx_first(ns_lwsearchctx_t *sctx) {
155	REQUIRE(sctx != NULL);
156	UNUSED(sctx);
157}
158
159isc_result_t
160ns_lwsearchctx_next(ns_lwsearchctx_t *sctx) {
161	REQUIRE(sctx != NULL);
162
163	if (sctx->list == NULL)
164		return (ISC_R_NOMORE);
165
166	if (sctx->searchname == NULL) {
167		INSIST (!sctx->exactfirst || sctx->doneexact);
168		if (sctx->exactfirst || sctx->doneexact)
169			return (ISC_R_NOMORE);
170		sctx->doneexact = ISC_TRUE;
171	} else {
172		if (sctx->exactfirst && !sctx->doneexact)
173			sctx->doneexact = ISC_TRUE;
174		else {
175			sctx->searchname = ISC_LIST_NEXT(sctx->searchname,
176							 link);
177			if (sctx->searchname == NULL && sctx->doneexact)
178				return (ISC_R_NOMORE);
179		}
180	}
181
182	return (ISC_R_SUCCESS);
183}
184
185isc_result_t
186ns_lwsearchctx_current(ns_lwsearchctx_t *sctx, dns_name_t *absname) {
187	dns_name_t *tname;
188	isc_boolean_t useexact = ISC_FALSE;
189
190	REQUIRE(sctx != NULL);
191
192	if (sctx->list == NULL ||
193	    sctx->searchname == NULL ||
194	    (sctx->exactfirst && !sctx->doneexact))
195		useexact = ISC_TRUE;
196
197	if (useexact) {
198		if (dns_name_isabsolute(sctx->relname))
199			tname = NULL;
200		else
201			tname = dns_rootname;
202	} else
203		tname = sctx->searchname;
204
205	return (dns_name_concatenate(sctx->relname, tname, absname, NULL));
206}