diff -ruN greylisting-0.5/greylisting.c greylisting-0.5.1/greylisting.c
--- greylisting-0.5/greylisting.c	2015-05-19 21:07:27.000000000 +0200
+++ greylisting-0.5.1/greylisting.c	2023-01-28 18:20:53.431490161 +0100
@@ -19,6 +19,13 @@
  * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  */
 
+ /*
+  * Roberto Puzzanghera gen 28, 2023
+  * Patched on line 455 because the configuration file cannot be retrieved
+  * The configuration file mysql.cnf is now hard coded to control/mysql.cnf
+  * and the option inside control/greylisting will be ignored.
+  */
+
 #define _BSD_SOURCE
 #include <stdio.h>
 #include <stdlib.h>
@@ -445,7 +452,8 @@
   }
 
   if (mysql_default_file)
-    mysql_options(mysql, MYSQL_READ_DEFAULT_FILE, mysql_default_file);
+    mysql_optionsv(mysql, MYSQL_READ_DEFAULT_FILE, (void *)"control/mysql.cnf");
+/*    mysql_options(mysql, MYSQL_READ_DEFAULT_FILE, mysql_default_file);*/
 
   /* connect to mysql */
   if (!mysql_real_connect(mysql, NULL, NULL, NULL, NULL, 0, NULL, 0))