r3897: add a locking infrastructure

(This used to be commit a99c0adb09e2bc77b876d23cb2d0711ccffd83ca)

6 files changed, 111 insertions, 18 deletions

diff --git a/source4/lib/ldb/common/ldb_modules.c b/source4/lib/ldb/common/ldb_modules.c
index 1a6a334b8d..71ec3fdc00 100644
--- a/source4/lib/ldb/common/ldb_modules.c
+++ b/source4/lib/ldb/common/ldb_modules.c
@@ -250,6 +250,22 @@ int ldb_next_rename_record(struct ldb_module *module, const char *olddn, const c
 	return module->next->ops->rename_record(module->next, olddn, newdn);
 }
 
+int ldb_next_named_lock(struct ldb_module *module, const char *lockname)
+{
+	if (!module->next) {
+		return -1;
+	}
+	return module->next->ops->named_lock(module->next, lockname);
+}
+
+int ldb_next_named_unlock(struct ldb_module *module, const char *lockname)
+{
+	if (!module->next) {
+		return -1;
+	}
+	return module->next->ops->named_unlock(module->next, lockname);
+}
+
 const char *ldb_next_errstring(struct ldb_module *module)
 {
 	if (!module->next) {
diff --git a/source4/lib/ldb/include/ldb_private.h b/source4/lib/ldb/include/ldb_private.h
index dfd388b8c6..720d8928dd 100644
--- a/source4/lib/ldb/include/ldb_private.h
+++ b/source4/lib/ldb/include/ldb_private.h
@@ -63,6 +63,8 @@ struct ldb_module_ops {
 	int (*modify_record)(struct ldb_module *, const struct ldb_message *);
 	int (*delete_record)(struct ldb_module *, const char *);
 	int (*rename_record)(struct ldb_module *, const char *, const char *);
+	int (*named_lock)(struct ldb_module *, const char *);
+	int (*named_unlock)(struct ldb_module *, const char *);
 	const char * (*errstring)(struct ldb_module *);
 
 	/* this is called when the alloc ops changes to ensure we 
@@ -101,6 +103,8 @@ int ldb_next_add_record(struct ldb_module *module, const struct ldb_message *mes
 int ldb_next_modify_record(struct ldb_module *module, const struct ldb_message *message);
 int ldb_next_delete_record(struct ldb_module *module, const char *dn);
 int ldb_next_rename_record(struct ldb_module *module, const char *olddn, const char *newdn);
+int ldb_next_named_lock(struct ldb_module *module, const char *lockname);
+int ldb_next_named_unlock(struct ldb_module *module, const char *lockname);
 const char *ldb_next_errstring(struct ldb_module *module);
 void ldb_next_cache_free(struct ldb_module *module);
 
diff --git a/source4/lib/ldb/ldb_ldap/ldb_ldap.c b/source4/lib/ldb/ldb_ldap/ldb_ldap.c
index 85604dfe76..d9640f247a 100644
--- a/source4/lib/ldb/ldb_ldap/ldb_ldap.c
+++ b/source4/lib/ldb/ldb_ldap/ldb_ldap.c
@@ -496,6 +496,35 @@ static int lldb_modify(struct ldb_module *module, const struct ldb_message *msg)
 	return ret;
 }
 
+static int lldb_lock(struct ldb_module *module, const char *lockname)
+{
+	struct ldb_context *ldb = module->ldb;
+	struct lldb_private *lldb = module->private_data;
+	int ret = 0;
+
+	if (lockname == NULL) {
+		return -1;
+	}
+
+	/* TODO implement a local locking mechanism here */
+
+	return ret;
+}
+
+static int lldb_unlock(struct ldb_module *module, const char *lockname)
+{
+	struct ldb_context *ldb = module->ldb;
+	struct lldb_private *lldb = module->private_data;
+	int ret = 0;
+
+	if (lockname == NULL) {
+		return -1;
+	}
+
+	/* TODO implement a local unlocking mechanism here */
+
+	return ret;
+}
 
 /*
   return extended error information
@@ -516,6 +545,8 @@ static const struct ldb_module_ops lldb_ops = {
 	lldb_modify,
 	lldb_delete,
 	lldb_rename,
+	lldb_lock,
+	lldb_unlock,
 	lldb_errstring
 };
 
diff --git a/source4/lib/ldb/ldb_tdb/ldb_tdb.c b/source4/lib/ldb/ldb_tdb/ldb_tdb.c
index 5f6af43f94..4049900a23 100644
--- a/source4/lib/ldb/ldb_tdb/ldb_tdb.c
+++ b/source4/lib/ldb/ldb_tdb/ldb_tdb.c
@@ -40,6 +40,8 @@
 #include "ldb/include/ldb_private.h"
 #include "ldb/ldb_tdb/ldb_tdb.h"
 
+#define LDBLOCK	"INT_LDBLOCK"
+
 /*
   form a TDB_DATA for a record key
   caller frees
@@ -122,14 +124,18 @@ failed:
 /*
   lock the database for write - currently a single lock is used
 */
-static int ltdb_lock(struct ldb_module *module)
+static int ltdb_lock(struct ldb_module *module, const char *lockname)
 {
 	struct ldb_context *ldb = module->ldb;
 	struct ltdb_private *ltdb = module->private_data;
 	TDB_DATA key;
 	int ret;
 
-	key = ltdb_key(module, "LDBLOCK");
+	if (lockname == NULL) {
+		return -1;
+	}
+
+	key = ltdb_key(module, lockname);
 	if (!key.dptr) {
 		return -1;
 	}
@@ -144,20 +150,26 @@ static int ltdb_lock(struct ldb_module *module)
 /*
   unlock the database after a ltdb_lock()
 */
-static void ltdb_unlock(struct ldb_module *module)
+static int ltdb_unlock(struct ldb_module *module, const char *lockname)
 {
 	struct ldb_context *ldb = module->ldb;
 	struct ltdb_private *ltdb = module->private_data;
 	TDB_DATA key;
 
-	key = ltdb_key(module, "LDBLOCK");
+	if (lockname == NULL) {
+		return -1;
+	}
+
+	key = ltdb_key(module, lockname);
 	if (!key.dptr) {
-		return;
+		return -1;
 	}
 
 	tdb_chainunlock(ltdb->tdb, key);
 
 	ldb_free(ldb, key.dptr);
+
+	return 0;
 }
 
 
@@ -231,12 +243,12 @@ static int ltdb_add(struct ldb_module *module, const struct ldb_message *msg)
 
 	ltdb->last_err_string = NULL;
 
-	if (ltdb_lock(module) != 0) {
+	if (ltdb_lock(module, LDBLOCK) != 0) {
 		return -1;
 	}
 
 	if (ltdb_cache_load(module) != 0) {
-		ltdb_unlock(module);
+		ltdb_unlock(module, LDBLOCK);
 		return -1;
 	}
 	
@@ -246,7 +258,7 @@ static int ltdb_add(struct ldb_module *module, const struct ldb_message *msg)
 		ltdb_modified(module, msg->dn);
 	}
 
-	ltdb_unlock(module);
+	ltdb_unlock(module, LDBLOCK);
 	return ret;
 }
 
@@ -284,12 +296,12 @@ static int ltdb_delete(struct ldb_module *module, const char *dn)
 
 	ltdb->last_err_string = NULL;
 
-	if (ltdb_lock(module) != 0) {
+	if (ltdb_lock(module, LDBLOCK) != 0) {
 		return -1;
 	}
 
 	if (ltdb_cache_load(module) != 0) {
-		ltdb_unlock(module);
+		ltdb_unlock(module, LDBLOCK);
 		return -1;
 	}
 
@@ -316,11 +328,11 @@ static int ltdb_delete(struct ldb_module *module, const char *dn)
 		ltdb_modified(module, dn);
 	}
 
-	ltdb_unlock(module);
+	ltdb_unlock(module, LDBLOCK);
 	return ret;
 
 failed:
-	ltdb_unlock(module);
+	ltdb_unlock(module, LDBLOCK);
 	return -1;
 }
 
@@ -573,12 +585,12 @@ static int ltdb_modify(struct ldb_module *module, const struct ldb_message *msg)
 
 	ltdb->last_err_string = NULL;
 
-	if (ltdb_lock(module) != 0) {
+	if (ltdb_lock(module, LDBLOCK) != 0) {
 		return -1;
 	}
 
 	if (ltdb_cache_load(module) != 0) {
-		ltdb_unlock(module);
+		ltdb_unlock(module, LDBLOCK);
 		return -1;
 	}
 
@@ -588,7 +600,7 @@ static int ltdb_modify(struct ldb_module *module, const struct ldb_message *msg)
 		ltdb_modified(module, msg->dn);
 	}
 
-	ltdb_unlock(module);
+	ltdb_unlock(module, LDBLOCK);
 
 	return ret;
 }
@@ -606,7 +618,7 @@ static int ltdb_rename(struct ldb_module *module, const char *olddn, const char
 
 	ltdb->last_err_string = NULL;
 
-	if (ltdb_lock(module) != 0) {
+	if (ltdb_lock(module, LDBLOCK) != 0) {
 		return -1;
 	}
 
@@ -641,11 +653,11 @@ static int ltdb_rename(struct ldb_module *module, const char *olddn, const char
 
 	ltdb->last_err_string = error_str;
 
-	ltdb_unlock(module);
+	ltdb_unlock(module, LDBLOCK);
 
 	return ret;
 failed:
-	ltdb_unlock(module);
+	ltdb_unlock(module, LDBLOCK);
 	return -1;
 }
 
@@ -692,6 +704,8 @@ static const struct ldb_module_ops ltdb_ops = {
 	ltdb_modify,
 	ltdb_delete,
 	ltdb_rename,
+	ltdb_lock,
+	ltdb_unlock,
 	ltdb_errstring,
 	ltdb_cache_free
 };
diff --git a/source4/lib/ldb/modules/skel.c b/source4/lib/ldb/modules/skel.c
index 331a2de5e4..3581969c18 100644
--- a/source4/lib/ldb/modules/skel.c
+++ b/source4/lib/ldb/modules/skel.c
@@ -80,6 +80,18 @@ static int skel_rename_record(struct ldb_module *module, const char *olddn, cons
 	return ldb_next_rename_record(module, olddn, newdn);
 }
 
+/* named_lock */
+static const char *skel_named_lock(struct ldb_module *module, const char *lockname)
+{
+	return ldb_next_named_lock(module, lockname);
+}
+
+/* named_unlock */
+static const char *skel_named_unlock(struct ldb_module *module, const char *lockname)
+{
+	return ldb_next_named_unlock(module, lockname);
+}
+
 /* return extended error information */
 static const char *skel_errstring(struct ldb_module *module)
 {
@@ -100,6 +112,8 @@ static const struct ldb_module_ops skel_ops = {
 	skel_modify_record,
 	skel_delete_record,
 	skel_rename_record,
+	skel_named_lock,
+	skel_named_unlock,
 	skel_errstring,
 	skel_cache_free
 };
diff --git a/source4/lib/ldb/modules/timestamps.c b/source4/lib/ldb/modules/timestamps.c
index 521c59d241..fde87ef4a6 100644
--- a/source4/lib/ldb/modules/timestamps.c
+++ b/source4/lib/ldb/modules/timestamps.c
@@ -230,6 +230,18 @@ static int timestamps_rename_record(struct ldb_module *module, const char *olddn
 	return ldb_next_rename_record(module, olddn, newdn);
 }
 
+static int timestamps_lock(struct ldb_module *module, const char *lockname)
+{
+	ldb_debug(module->ldb, LDB_DEBUG_TRACE, "timestamps_lock\n");
+	return ldb_next_named_lock(module, lockname);
+}
+
+static int timestamps_unlock(struct ldb_module *module, const char *lockname)
+{
+	ldb_debug(module->ldb, LDB_DEBUG_TRACE, "timestamps_unlock\n");
+	return ldb_next_named_unlock(module, lockname);
+}
+
 /* return extended error information */
 static const char *timestamps_errstring(struct ldb_module *module)
 {
@@ -252,6 +264,8 @@ static const struct ldb_module_ops timestamps_ops = {
 	timestamps_modify_record,
 	timestamps_delete_record,
 	timestamps_rename_record,
+	timestamps_lock,
+	timestamps_unlock,
 	timestamps_errstring,
 	timestamps_cache_free
 };