594. [func] sdb drivers are now assumed to not be thread-safe

unless the DNS_SDBFLAG_THREADSAFE flag is supplied.
(also make the dirdb.c driver specify DNS_SDBFLAG_THREADSAFE)

CHANGES

@@ -1,4 +1,7 @@
 
+ 594.	[func]		sdb drivers are now assumed to not be thread-safe
+			unless the DNS_SDBFLAG_THREADSAFE flag is supplied.
+
  593.	[bug]		If a secure zone was missing all its NXTs and
 			a dynamic update was attempted, the server entered
 			an infinite loop.

contrib/sdb/dir/dirdb.c

@@ -15,7 +15,7 @@
  * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: dirdb.c,v 1.6 2000/12/06 00:59:06 bwelling Exp $ */
+/* $Id: dirdb.c,v 1.7 2000/12/06 01:08:37 bwelling Exp $ */
 
 #include <config.h>
 
@@ -178,7 +178,8 @@ static dns_sdbmethods_t dirdb_methods = {
 isc_result_t
 dirdb_init(void) {
 	unsigned int flags;
-	flags = DNS_SDBFLAG_RELATIVEOWNER | DNS_SDBFLAG_RELATIVERDATA;
+	flags = DNS_SDBFLAG_RELATIVEOWNER | DNS_SDBFLAG_RELATIVERDATA |
+		DNS_SDBFLAG_THREADSAFE;
 	return (dns_sdb_register("dir", &dirdb_methods, ns_g_mctx, flags,
 				 ns_g_mctx, &dirdb));
 }

contrib/sdb/dirdb.c

@@ -15,7 +15,7 @@
  * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: dirdb.c,v 1.6 2000/12/06 00:59:06 bwelling Exp $ */
+/* $Id: dirdb.c,v 1.7 2000/12/06 01:08:37 bwelling Exp $ */
 
 #include <config.h>
 
@@ -178,7 +178,8 @@ static dns_sdbmethods_t dirdb_methods = {
 isc_result_t
 dirdb_init(void) {
 	unsigned int flags;
-	flags = DNS_SDBFLAG_RELATIVEOWNER | DNS_SDBFLAG_RELATIVERDATA;
+	flags = DNS_SDBFLAG_RELATIVEOWNER | DNS_SDBFLAG_RELATIVERDATA |
+		DNS_SDBFLAG_THREADSAFE;
 	return (dns_sdb_register("dir", &dirdb_methods, ns_g_mctx, flags,
 				 ns_g_mctx, &dirdb));
 }

lib/dns/include/dns/sdb.h

@@ -15,7 +15,7 @@
  * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: sdb.h,v 1.10 2000/11/16 23:10:19 gson Exp $ */
+/* $Id: sdb.h,v 1.11 2000/12/06 01:08:39 bwelling Exp $ */
 
 #ifndef DNS_SDB_H
 #define DNS_SDB_H 1
@@ -90,6 +90,7 @@ ISC_LANG_BEGINDECLS
 
 #define DNS_SDBFLAG_RELATIVEOWNER 0x00000001U
 #define DNS_SDBFLAG_RELATIVERDATA 0x00000002U
+#define DNS_SDBFLAG_THREADSAFE 0x00000004U
 
 isc_result_t
 dns_sdb_register(const char *drivername, const dns_sdbmethods_t *methods,
@@ -144,6 +145,10 @@ dns_sdb_register(const char *drivername, const dns_sdbmethods_t *methods,
  * include relative names.  Otherwise, all names in the rdata string must
  * be absolute.  Be aware that if relative names are allowed, any
  * absolute names must contain a trailing dot.
+ *
+ * If flags includes DNS_SDBFLAG_THREADSAFE, the driver must be able to
+ * handle multiple lookups in parallel.  Otherwise, calls into the driver
+ * are serialized.
  */
 
 void

lib/dns/sdb.c

@@ -15,7 +15,7 @@
  * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: sdb.c,v 1.20 2000/12/01 01:22:43 marka Exp $ */
+/* $Id: sdb.c,v 1.21 2000/12/06 01:08:38 bwelling Exp $ */
 
 #include <config.h>
 
@@ -114,6 +114,20 @@ typedef struct sdb_rdatasetiter {
 /* This is a reasonable value */
 #define SDB_DEFAULT_TTL		(60 * 60 * 24)
 
+#define MAYBE_LOCK(sdb)							\
+	do {								\
+		unsigned int flags = sdb->implementation->flags;	\
+		if ((flags & DNS_SDBFLAG_THREADSAFE) == 0)		\
+			LOCK(&sdb->lock);				\
+	} while (0)
+
+#define MAYBE_UNLOCK(sdb)						\
+	do {								\
+		unsigned int flags = sdb->implementation->flags;	\
+		if ((flags & DNS_SDBFLAG_THREADSAFE) == 0)		\
+			UNLOCK(&sdb->lock);				\
+	} while (0)
+
 static int dummy;
 
 static isc_result_t dns_sdb_create(isc_mem_t *mctx, dns_name_t *origin,
@@ -193,6 +207,9 @@ dns_sdb_register(const char *drivername, const dns_sdbmethods_t *methods,
 	REQUIRE(methods->lookup != NULL);
 	REQUIRE(mctx != NULL);
 	REQUIRE(sdbimp != NULL && *sdbimp == NULL);
+	REQUIRE((flags & ~(DNS_SDBFLAG_RELATIVEOWNER |
+			   DNS_SDBFLAG_RELATIVERDATA |
+			   DNS_SDBFLAG_THREADSAFE)) == 0);
 
 	imp = isc_mem_get(mctx, sizeof(dns_sdbimplementation_t));
 	if (imp == NULL)
@@ -663,14 +680,18 @@ findnode(dns_db_t *db, dns_name_t *name, isc_boolean_t create,
 
 	isorigin = dns_name_equal(name, &sdb->common.origin);
 
+	MAYBE_LOCK(sdb);
 	result = imp->methods->lookup(sdb->zone, namestr, sdb->dbdata, node);
+	MAYBE_UNLOCK(sdb);
 	if (result != ISC_R_SUCCESS && !isorigin) {
 		destroynode(node);
 		return (result);
 	}
 
 	if (isorigin && imp->methods->authority != NULL) {
+		MAYBE_LOCK(sdb);
 		result = imp->methods->authority(sdb->zone, sdb->dbdata, node);
+		MAYBE_UNLOCK(sdb);
 		if (result != ISC_R_SUCCESS) {
 			destroynode(node);
 			return (result);
@@ -937,7 +958,9 @@ createiterator(dns_db_t *db, isc_boolean_t relative_names,
 	sdbiter->current = NULL;
 	sdbiter->origin = NULL;
 
+	MAYBE_LOCK(sdb);
 	result = imp->methods->allnodes(sdb->zone, sdb->dbdata, sdbiter);
+	MAYBE_UNLOCK(sdb);
 	if (result != ISC_R_SUCCESS) {
 		dbiterator_destroy((dns_dbiterator_t **)&sdbiter);
 		return (result);