Add security utils

src/include/distributed/security_utils.h

@@ -0,0 +1,26 @@
+/*-------------------------------------------------------------------------
+ *
+ * security_utils.h
+ *   security related utility functions.
+ *
+ * Copyright (c) Citus Data, Inc.
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#ifndef SECURITY_UTILS_H_
+#define SECURITY_UTILS_H_
+
+#include "postgres.h"
+#include "miscadmin.h"
+
+#define PushCitusSecurityContext() \
+    Oid savedUserId_DONTUSE = InvalidOid; \
+	int savedSecurityContext_DONTUSE = 0; \
+    GetUserIdAndSecContext(&savedUserId_DONTUSE, &savedSecurityContext_DONTUSE); \
+	SetUserIdAndSecContext(CitusExtensionOwner(), SECURITY_LOCAL_USERID_CHANGE);
+
+#define PopCitusSecurityContext() \
+    SetUserIdAndSecContext(savedUserId_DONTUSE, savedSecurityContext_DONTUSE);
+
+#endif