contrib/bind-9.5.2/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
  40 isc_result_t
  41 ns_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
  67 void
  68 ns_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
  81 void
  82 ns_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
 111 isc_result_t
 112 ns_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
 133 void
 134 ns_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
 153 void
 154 ns_lwsearchctx_first(ns_lwsearchctx_t *sctx) {
 155         REQUIRE(sctx != NULL);
 156         UNUSED(sctx);
 157 }
 158
 159 isc_result_t
 160 ns_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
 185 isc_result_t
 186 ns_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 }