diff --git a/include/my_sys.h b/include/my_sys.h
index 325c473eb23..11993c02516 100644
--- a/include/my_sys.h
+++ b/include/my_sys.h
@@ -903,6 +903,7 @@ static inline char *safe_strdup_root(MEM_ROOT *root, const char *str)
 }
 extern char *strmake_root(MEM_ROOT *root,const char *str,size_t len);
 extern void *memdup_root(MEM_ROOT *root,const void *str, size_t len);
+extern LEX_CSTRING safe_lexcstrdup_root(MEM_ROOT *root, const LEX_CSTRING str);
 extern my_bool my_compress(uchar *, size_t *, size_t *);
 extern my_bool my_uncompress(uchar *, size_t , size_t *);
 extern uchar *my_compress_alloc(const uchar *packet, size_t *len,
diff --git a/mysys/my_alloc.c b/mysys/my_alloc.c
index abcc692211a..576142343f4 100644
--- a/mysys/my_alloc.c
+++ b/mysys/my_alloc.c
@@ -492,3 +492,14 @@ void *memdup_root(MEM_ROOT *root, const void *str, size_t len)
     memcpy(pos,str,len);
   return pos;
 }
+
+LEX_CSTRING safe_lexcstrdup_root(MEM_ROOT *root, const LEX_CSTRING str)
+{
+  LEX_CSTRING res;
+  if (str.length)
+    res.str= strmake_root(root, str.str, str.length);
+  else
+    res.str= (const char *)"";
+  res.length= str.length;
+  return res;
+}
diff --git a/sql/sql_acl.cc b/sql/sql_acl.cc
index bf18581de4f..dafd4703a02 100644
--- a/sql/sql_acl.cc
+++ b/sql/sql_acl.cc
@@ -152,8 +152,7 @@ public:
     if (!dst)
       return 0;
     *dst= *this;
-    dst->user.str= safe_strdup_root(root, user.str);
-    dst->user.length= user.length;
+    dst->user= safe_lexcstrdup_root(root, user);
     dst->ssl_cipher= safe_strdup_root(root, ssl_cipher);
     dst->x509_issuer= safe_strdup_root(root, x509_issuer);
     dst->x509_subject= safe_strdup_root(root, x509_subject);
@@ -161,11 +160,10 @@ public:
         plugin.str == old_password_plugin_name.str)
       dst->plugin= plugin;
     else
-      dst->plugin.str= strmake_root(root, plugin.str, plugin.length);
-    dst->auth_string.str= safe_strdup_root(root, auth_string.str);
+      dst->plugin= safe_lexcstrdup_root(root, plugin);
+    dst->auth_string= safe_lexcstrdup_root(root, auth_string);
     dst->host.hostname= safe_strdup_root(root, host.hostname);
-    dst->default_rolename.str= safe_strdup_root(root, default_rolename.str);
-    dst->default_rolename.length= default_rolename.length;
+    dst->default_rolename= safe_lexcstrdup_root(root, default_rolename);
     bzero(&dst->role_grants, sizeof(role_grants));
     return dst;
   }
@@ -1337,8 +1335,7 @@ ACL_ROLE::ACL_ROLE(ACL_USER *user, MEM_ROOT *root) : counter(0)
   access= user->access;
   /* set initial role access the same as the table row privileges */
   initial_role_access= user->access;
-  this->user.str= safe_strdup_root(root, user->user.str);
-  this->user.length= user->user.length;
+  this->user= safe_lexcstrdup_root(root, user->user);
   bzero(&role_grants, sizeof(role_grants));
   bzero(&parent_grantee, sizeof(parent_grantee));
   flags= IS_ROLE;
@@ -2628,11 +2625,9 @@ static void acl_update_user(const char *user, const char *host,
       if (plugin->str[0])
       {
         acl_user->plugin= *plugin;
-        acl_user->auth_string.str= auth->str ?
-          strmake_root(&acl_memroot, auth->str, auth->length) : const_cast<char*>("");
-        acl_user->auth_string.length= auth->length;
+        acl_user->auth_string= safe_lexcstrdup_root(&acl_memroot, *auth);
         if (fix_user_plugin_ptr(acl_user))
-          acl_user->plugin.str= strmake_root(&acl_memroot, plugin->str, plugin->length);
+          acl_user->plugin= safe_lexcstrdup_root(&acl_memroot, *plugin);
       }
       else
         if (password[0])
@@ -2707,11 +2702,9 @@ static void acl_insert_user(const char *user, const char *host,
   if (plugin->str[0])
   {
     acl_user.plugin= *plugin;
-    acl_user.auth_string.str= auth->str ?
-      strmake_root(&acl_memroot, auth->str, auth->length) : const_cast<char*>("");
-    acl_user.auth_string.length= auth->length;
+    acl_user.auth_string= safe_lexcstrdup_root(&acl_memroot, *auth);
     if (fix_user_plugin_ptr(&acl_user))
-      acl_user.plugin.str= strmake_root(&acl_memroot, plugin->str, plugin->length);
+      acl_user.plugin= safe_lexcstrdup_root(&acl_memroot, *plugin);
   }
   else
   {
@@ -3299,8 +3292,7 @@ bool change_password(THD *thd, LEX_USER *user)
   if (acl_user->plugin.str == native_password_plugin_name.str ||
       acl_user->plugin.str == old_password_plugin_name.str)
   {
-    acl_user->auth_string.str= strmake_root(&acl_memroot, user->pwhash.str, user->pwhash.length);
-    acl_user->auth_string.length= user->pwhash.length;
+    acl_user->auth_string= safe_lexcstrdup_root(&acl_memroot, user->pwhash);
     set_user_salt(acl_user, user->pwhash.str, user->pwhash.length);
 
     set_user_plugin(acl_user, user->pwhash.length);
@@ -9608,8 +9600,7 @@ static int handle_grant_struct(enum enum_acl_lists struct_no, bool drop,
       my_hash_delete(&acl_roles, (uchar*) acl_role);
       DBUG_RETURN(1);
     }
-    acl_role->user.str= strdup_root(&acl_memroot, user_to->user.str);
-    acl_role->user.length= user_to->user.length;
+    acl_role->user= safe_lexcstrdup_root(&acl_memroot, user_to->user);
 
     my_hash_update(&acl_roles, (uchar*) acl_role, (uchar*) old_key,
                    old_key_length);
@@ -9800,8 +9791,7 @@ static int handle_grant_struct(enum enum_acl_lists struct_no, bool drop,
     {
       switch ( struct_no ) {
       case USER_ACL:
-        acl_user->user.str= strdup_root(&acl_memroot, user_to->user.str);
-        acl_user->user.length= user_to->user.length;
+        acl_user->user= safe_lexcstrdup_root(&acl_memroot, user_to->user);
         update_hostname(&acl_user->host, strdup_root(&acl_memroot, user_to->host.str));
         acl_user->hostname_length= strlen(acl_user->host.hostname);
         break;
diff --git a/sql/sql_trigger.cc b/sql/sql_trigger.cc
index fd128f8dc1c..5d9526ca274 100644
--- a/sql/sql_trigger.cc
+++ b/sql/sql_trigger.cc
@@ -35,16 +35,6 @@
 #include "sp_cache.h"                     // sp_invalidate_cache
 #include <mysys_err.h>
 
-LEX_CSTRING *make_lex_string(LEX_CSTRING *lex_str,
-                             const char* str, size_t length,
-                             MEM_ROOT *mem_root)
-{
-  if (!(lex_str->str= strmake_root(mem_root, str, length)))
-    return 0;
-  lex_str->length= length;
-  return lex_str;
-}
-
 /*************************************************************************/
 
 /**
@@ -1503,8 +1493,8 @@ bool Table_triggers_list::check_n_load(THD *thd, const LEX_CSTRING *db,
 
           if (likely((name= error_handler.get_trigger_name())))
           {
-            if (unlikely(!(make_lex_string(&trigger->name, name->str,
-                                           name->length, &table->mem_root))))
+            trigger->name= safe_lexcstrdup_root(&table->mem_root, *name);
+            if (unlikely(!trigger->name.str))
               goto err_with_lex_cleanup;
           }
           trigger->definer= ((!trg_definer || !trg_definer->length) ?