MDEV-10492: Assertion failure on shutdown when wsrep_sst_auth set in config

The memory alloc-ed initially for wsrep_sst_auth to store the
value specified in config was lost as the global variable was
reset while in process of masking it and thus, could never be
reclaimed on shutdown.

mysql-test/suite/galera/r/galera_var_sst_auth.result

+#
+# MDEV-10492: Assertion failure on shutdown when wsrep_sst_auth set in config
+#
+SELECT @@global.wsrep_sst_auth;
+@@global.wsrep_sst_auth
+********
+SET @@global.wsrep_sst_auth='foo:bar';
+SELECT @@global.wsrep_sst_auth;
+@@global.wsrep_sst_auth
+********
+disconnect node_2;
+disconnect node_1;

mysql-test/suite/galera/t/galera_var_sst_auth.opt

+--wsrep_sst_auth=root:

mysql-test/suite/galera/t/galera_var_sst_auth.test

+--source include/galera_cluster.inc
+--source include/have_innodb.inc
+
+--echo #
+--echo # MDEV-10492: Assertion failure on shutdown when wsrep_sst_auth set in config
+--echo #
+
+SELECT @@global.wsrep_sst_auth;
+SET @@global.wsrep_sst_auth='foo:bar';
+SELECT @@global.wsrep_sst_auth;
+
+--source include/galera_end.inc

sql/wsrep_mysqld.cc

@@ -577,7 +577,7 @@ int wsrep_init()
     return 1;
   }
 
-  wsrep_sst_auth_init(wsrep_sst_auth);
+  wsrep_sst_auth_init();
 
   wsrep_ready_set(FALSE);
   assert(wsrep_provider);

sql/wsrep_sst.cc

@@ -169,10 +169,9 @@ bool wsrep_sst_auth_update (sys_var *self, THD* thd, enum_var_type type)
     return sst_auth_real_set (wsrep_sst_auth);
 }
 
-void wsrep_sst_auth_init (const char* value)
+void wsrep_sst_auth_init ()
 {
-    if (wsrep_sst_auth == value) wsrep_sst_auth = NULL;
-    if (value) sst_auth_real_set (value);
+  sst_auth_real_set(wsrep_sst_auth);
 }
 
 bool  wsrep_sst_donor_check (sys_var *self, THD* thd, set_var* var)

sql/wsrep_sst.h

@@ -64,6 +64,7 @@ extern void wsrep_sst_grab();
 extern bool wsrep_sst_wait();
 /*! Signals wsrep that initialization is complete, writesets can be applied */
 extern bool wsrep_sst_continue();
+extern void wsrep_sst_auth_init();
 extern void wsrep_sst_auth_free();
 
 extern void wsrep_SE_init_grab();   /*! grab init critical section */

sql/wsrep_var.h

@@ -81,7 +81,6 @@ extern bool wsrep_sst_receive_address_update UPDATE_ARGS;
 
 extern bool wsrep_sst_auth_check             CHECK_ARGS;
 extern bool wsrep_sst_auth_update            UPDATE_ARGS;
-extern void wsrep_sst_auth_init              INIT_ARGS;
 
 extern bool wsrep_sst_donor_check            CHECK_ARGS;
 extern bool wsrep_sst_donor_update           UPDATE_ARGS;
@@ -98,7 +97,6 @@ extern bool wsrep_desync_update              UPDATE_ARGS;
 #define wsrep_provider_init(X)
 #define wsrep_init_vars() (0)
 #define wsrep_start_position_init(X)
-#define wsrep_sst_auth_init(X)
 
 #endif /* WITH_WSREP */
 #endif /* WSREP_VAR_H */