1 files changed, 295 insertions, 0 deletions
diff --git a/lib/dns/dbtable.c b/lib/dns/dbtable.c
new file mode 100644
index 00000000..e21d5792
--- /dev/null
+++ b/lib/dns/dbtable.c
@@ -0,0 +1,295 @@
+/*
+ * Copyright (C) 1999, 2000  Internet Software Consortium.
+ * 
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
+ * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
+ * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
+ * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
+ * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
+ * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
+ * SOFTWARE.
+ */
+
+/*
+ * $Id: dbtable.c,v 1.13 2000/02/03 23:43:46 halley Exp $
+ */
+
+/*
+ * Principal Author: DCL
+ */
+
+#include <config.h>
+
+#include <isc/assertions.h>
+#include <isc/rwlock.h>
+#include <isc/util.h>
+
+#include <dns/dbtable.h>
+#include <dns/db.h>
+#include <dns/rbt.h>
+
+struct dns_dbtable {
+	/* Unlocked. */
+	unsigned int		magic;
+	isc_mem_t *		mctx;
+	dns_rdataclass_t	rdclass;
+	isc_mutex_t		lock;
+	isc_rwlock_t		tree_lock;
+	/* Locked by lock. */
+	unsigned int		references;
+	/* Locked by tree_lock. */
+	dns_rbt_t *		rbt;
+	dns_db_t *		default_db;
+};
+
+#define DBTABLE_MAGIC		0x44422D2DU /* DB--. */
+#define VALID_DBTABLE(dbtable)	((dbtable) != NULL && \
+				 (dbtable)->magic == DBTABLE_MAGIC)
+
+static void
+dbdetach(void *data, void *arg) {
+	dns_db_t *db = data;
+
+	(void)arg;
+
+	dns_db_detach(&db);
+}
+
+isc_result_t
+dns_dbtable_create(isc_mem_t *mctx, dns_rdataclass_t rdclass,
+		   dns_dbtable_t **dbtablep)
+{
+	dns_dbtable_t *dbtable;
+	isc_result_t result;
+	isc_result_t iresult;
+
+	REQUIRE(mctx != NULL);
+	REQUIRE(dbtablep != NULL && *dbtablep == NULL);
+
+	dbtable = (dns_dbtable_t *)isc_mem_get(mctx, sizeof(*dbtable));
+	if (dbtable == NULL)
+		return (DNS_R_NOMEMORY);
+
+	dbtable->rbt = NULL;
+	result = dns_rbt_create(mctx, dbdetach, NULL, &dbtable->rbt);
+	if (result != DNS_R_SUCCESS)
+		goto clean1;
+
+	iresult = isc_mutex_init(&dbtable->lock);
+	if (iresult != ISC_R_SUCCESS) {
+		UNEXPECTED_ERROR(__FILE__, __LINE__,
+				 "isc_lock_init() failed: %s",
+				 isc_result_totext(result));
+		result = DNS_R_UNEXPECTED;
+		goto clean2;
+	}
+
+	iresult = isc_rwlock_init(&dbtable->tree_lock, 0, 0);
+	if (iresult != ISC_R_SUCCESS) {
+		UNEXPECTED_ERROR(__FILE__, __LINE__,
+				 "isc_rwlock_init() failed: %s",
+				 isc_result_totext(result));
+		result = DNS_R_UNEXPECTED;
+		goto clean3;
+	}
+
+	dbtable->default_db = NULL;
+	dbtable->mctx = mctx;
+	dbtable->rdclass = rdclass;
+	dbtable->magic = DBTABLE_MAGIC;
+	dbtable->references = 1;
+
+	*dbtablep = dbtable;
+
+	return (DNS_R_SUCCESS);
+
+ clean3:
+	(void)isc_mutex_destroy(&dbtable->lock);
+
+ clean2:
+	dns_rbt_destroy(&dbtable->rbt);
+
+ clean1:
+	isc_mem_put(mctx, dbtable, sizeof(*dbtable));
+
+	return (result);
+}
+
+static inline void
+dbtable_free(dns_dbtable_t *dbtable) {
+	/*
+	 * Caller must ensure that it is safe to
+	 * call.
+	 */
+
+	RWLOCK(&dbtable->tree_lock, isc_rwlocktype_write);
+
+	if (dbtable->default_db != NULL)
+		dns_db_detach(&dbtable->default_db);
+
+	dns_rbt_destroy(&dbtable->rbt);
+
+	RWUNLOCK(&dbtable->tree_lock, isc_rwlocktype_write);
+
+	isc_rwlock_destroy(&dbtable->tree_lock);
+
+	dbtable->magic = 0;
+
+	isc_mem_put(dbtable->mctx, dbtable, sizeof(*dbtable));
+}
+
+void
+dns_dbtable_attach(dns_dbtable_t *source, dns_dbtable_t **targetp) {
+	REQUIRE(VALID_DBTABLE(source));
+	REQUIRE(targetp != NULL && *targetp == NULL);
+	
+	LOCK(&source->lock);
+
+	INSIST(source->references > 0);
+	source->references++;
+	INSIST(source->references != 0);
+
+	UNLOCK(&source->lock);
+
+	*targetp = source;
+}
+
+void
+dns_dbtable_detach(dns_dbtable_t **dbtablep) {
+	dns_dbtable_t *dbtable;
+	isc_boolean_t free_dbtable = ISC_FALSE;
+
+	REQUIRE(dbtablep != NULL);
+	dbtable = *dbtablep;
+	REQUIRE(VALID_DBTABLE(dbtable));
+	
+	LOCK(&dbtable->lock);
+
+	INSIST(dbtable->references > 0);
+	dbtable->references--;
+	if (dbtable->references == 0)
+		free_dbtable = ISC_TRUE;
+
+	UNLOCK(&dbtable->lock);
+
+	if (free_dbtable)
+		dbtable_free(dbtable);
+
+	*dbtablep = NULL;
+}
+
+isc_result_t
+dns_dbtable_add(dns_dbtable_t *dbtable, dns_db_t *db) {
+	isc_result_t result;
+	dns_db_t *clone;
+
+	REQUIRE(VALID_DBTABLE(dbtable));
+	REQUIRE(dns_db_class(db) == dbtable->rdclass);
+
+	clone = NULL;
+	dns_db_attach(db, &clone);
+
+	RWLOCK(&dbtable->tree_lock, isc_rwlocktype_write);
+	result = dns_rbt_addname(dbtable->rbt, dns_db_origin(clone), clone);
+	RWUNLOCK(&dbtable->tree_lock, isc_rwlocktype_write);
+
+	return (result);
+}
+
+void
+dns_dbtable_remove(dns_dbtable_t *dbtable, dns_db_t *db) {
+	dns_db_t *stored_data = NULL;
+	isc_result_t result;
+	dns_name_t *name;
+
+	REQUIRE(VALID_DBTABLE(dbtable));
+	
+	name = dns_db_origin(db);
+
+	/*
+	 * There is a requirement that the association of name with db
+	 * be verified.  With the current rbt.c this is expensive to do,
+	 * because effectively two find operations are being done, but
+	 * deletion is relatively infrequent.
+	 */
+
+	RWLOCK(&dbtable->tree_lock, isc_rwlocktype_write);
+
+	result = dns_rbt_findname(dbtable->rbt, name, NULL,
+				  (void **)&stored_data);
+
+	if (result == DNS_R_SUCCESS) {
+		INSIST(stored_data == db);
+
+		dns_rbt_deletename(dbtable->rbt, name, ISC_FALSE);
+	}
+
+	RWUNLOCK(&dbtable->tree_lock, isc_rwlocktype_write);
+}
+
+void
+dns_dbtable_adddefault(dns_dbtable_t *dbtable, dns_db_t *db) {
+	REQUIRE(VALID_DBTABLE(dbtable));
+	REQUIRE(dbtable->default_db == NULL);
+	REQUIRE(dns_name_compare(dns_db_origin(db), dns_rootname) == 0);
+
+	RWLOCK(&dbtable->tree_lock, isc_rwlocktype_write);
+
+	dbtable->default_db = NULL;
+	dns_db_attach(db, &dbtable->default_db);
+
+	RWUNLOCK(&dbtable->tree_lock, isc_rwlocktype_write);
+}
+
+void
+dns_dbtable_getdefault(dns_dbtable_t *dbtable, dns_db_t **dbp) {
+	REQUIRE(VALID_DBTABLE(dbtable));
+	REQUIRE(dbp != NULL && *dbp == NULL);
+
+	RWLOCK(&dbtable->tree_lock, isc_rwlocktype_read);
+
+	dns_db_attach(dbtable->default_db, dbp);
+
+	RWUNLOCK(&dbtable->tree_lock, isc_rwlocktype_read);
+}
+
+void
+dns_dbtable_removedefault(dns_dbtable_t *dbtable) {
+	REQUIRE(VALID_DBTABLE(dbtable));
+
+	RWLOCK(&dbtable->tree_lock, isc_rwlocktype_write);
+
+	dns_db_detach(&dbtable->default_db);
+
+	RWUNLOCK(&dbtable->tree_lock, isc_rwlocktype_write);
+}
+
+isc_result_t
+dns_dbtable_find(dns_dbtable_t *dbtable, dns_name_t *name, dns_db_t **dbp) {
+	dns_db_t *stored_data = NULL;
+	isc_result_t result;
+
+	REQUIRE(dbp != NULL && *dbp == NULL);
+
+	RWLOCK(&dbtable->tree_lock, isc_rwlocktype_read);
+
+	result = dns_rbt_findname(dbtable->rbt, name, NULL,
+				  (void **)&stored_data);
+
+	if (result == DNS_R_SUCCESS || result == DNS_R_PARTIALMATCH)
+		dns_db_attach(stored_data, dbp);
+	else if (dbtable->default_db != NULL) {
+		dns_db_attach(dbtable->default_db, dbp);
+		result = DNS_R_PARTIALMATCH;
+	} else
+		result = DNS_R_NOTFOUND;
+
+	RWUNLOCK(&dbtable->tree_lock, isc_rwlocktype_read);
+
+	return (result);
+}