s3:registry: add regdb_trans_do(): a transaction wrapper that will check the regdb...

If the version has changed since initialization, the write will
fail with ACCESS_DENIED.

diff --git a/source3/registry/reg_backend_db.c b/source3/registry/reg_backend_db.c
index 44f84939e0d23ce6b94453ee515b3f958e1afca9..3d6f74ecb78831f9d4fe597ccc1e37b0102fe566 100644 (file)
--- a/source3/registry/reg_backend_db.c
+++ b/source3/registry/reg_backend_db.c
@@ -57,6 +57,48 @@ static WERROR regdb_create_subkey_internal(struct db_context *db,
                                           const char *key,
                                           const char *subkey);
 
+
+struct regdb_trans_ctx {
+       NTSTATUS (*action)(struct db_context *, void *);
+       void *private_data;
+};
+
+static NTSTATUS regdb_trans_do_action(struct db_context *db, void *private_data)
+{
+       NTSTATUS status;
+       int32_t version_id;
+       struct regdb_trans_ctx *ctx = (struct regdb_trans_ctx *)private_data;
+
+       version_id = dbwrap_fetch_int32(db, REGDB_VERSION_KEYNAME);
+
+       if (version_id != REGVER_V3) {
+               DEBUG(0, ("ERROR: changed registry version %d found while "
+                         "trying to write to the registry. Version %d "
+                         "expected.  Denying access.\n",
+                         version_id, REGVER_V3));
+               return NT_STATUS_ACCESS_DENIED;
+       }
+
+       status = ctx->action(db,  ctx->private_data);
+       return status;
+}
+
+static WERROR regdb_trans_do(struct db_context *db,
+                            NTSTATUS (*action)(struct db_context *, void *),
+                            void *private_data)
+{
+       NTSTATUS status;
+       struct regdb_trans_ctx ctx;
+
+
+       ctx.action = action;
+       ctx.private_data = private_data;
+
+       status = dbwrap_trans_do(db, regdb_trans_do_action, &ctx);
+
+       return ntstatus_to_werror(status);
+}
+
 /* List the deepest path into the registry.  All part components will be created.*/
 
 /* If you want to have a part of the path controlled by the tdb and part by