Bug #48321 CURRENT_USER() incorrectly replicated for DROP/RENAME USER;

            REVOKE/GRANT; ALTER EVENT.

The following statements support the CURRENT_USER() where a user is needed.
  DROP USER 
  RENAME USER CURRENT_USER() ...
  GRANT ... TO CURRENT_USER()
  REVOKE ... FROM CURRENT_USER()
  ALTER DEFINER = CURRENT_USER() EVENT
but, When these statements are binlogged, CURRENT_USER() just is binlogged
as 'CURRENT_USER()', it is not expanded to the real user name. When slave 
executes the log event, 'CURRENT_USER()' is expand to the user of slave 
SQL thread, but SQL thread's user name always NULL. This breaks the replication.

After this patch, All above statements are rewritten when they are binlogged.
The CURRENT_USER() is expanded to the real user's name and host.

1 files changed, 39 insertions, 40 deletions

diff --git a/sql/events.cc b/sql/events.cc
index 4c6dd0f35d1..6c8bdb1ea0f 100644
--- a/sql/events.cc
+++ b/sql/events.cc
@@ -341,31 +341,48 @@ common_1_lev_code:
 }
 
 
-/**
-  Create a new query string for removing executable comments 
-  for avoiding leak and keeping consistency of the execution 
-  on master and slave.
-  
+/*
+  Binlog '{CREATE|ALTER} EVENT' statements.
+  Definer part is always rewritten, for definer can be CURRENT_USER() function.
+
   @param[in] thd                 Thread handler
-  @param[in] buf                 Query string
+  @param[in] create              CREATE or ALTER statement
 
   @return
-             0           ok
-             1           error
+             FASE           ok
+             TRUE           error
 */
-static int
-create_query_string(THD *thd, String *buf)
+static bool event_write_bin_log(THD *thd, bool create)
 {
-  /* Append the "CREATE" part of the query */
-  if (buf->append(STRING_WITH_LEN("CREATE ")))
-    return 1;
-  /* Append definer */
-  append_definer(thd, buf, &(thd->lex->definer->user), &(thd->lex->definer->host));
+  String log_query;
+  if (create)
+  {
+    /* Append the "CREATE" part of the query */
+    if (log_query.append(STRING_WITH_LEN("CREATE ")))
+      return TRUE;
+  }
+  else
+  {
+    /* Append the "ALETR " part of the query */
+    if (log_query.append(STRING_WITH_LEN("ALTER ")))
+      return TRUE;
+  }
+
+  /* Append definer
+     If the definer is not set or set to CURRENT_USER, the value of CURRENT_USER
+     will be written into the binary log as the definer for the SQL thread.
+   */
+  append_definer(thd, &log_query, &(thd->lex->definer->user),
+                 &(thd->lex->definer->host));
+
   /* Append the left part of thd->query after "DEFINER" part */
-  if (buf->append(thd->lex->stmt_definition_begin))
-    return 1;
- 
-  return 0;
+  if (log_query.append(thd->lex->stmt_definition_begin,
+                       thd->lex->stmt_definition_end -
+                       thd->lex->stmt_definition_begin))
+    return TRUE;
+
+  return write_bin_log(thd, TRUE, log_query.c_ptr_safe(), log_query.length())
+          != 0;
 }
 
 /**
@@ -380,8 +397,7 @@ create_query_string(THD *thd, String *buf)
   @sa Events::drop_event for the notes about locking, pre-locking
   and Events DDL.
 
-  @retval  FALSE  OK
-  @retval  TRUE   Error (reported)
+  @retval  FALSE  OK @retval  TRUE   Error (reported)
 */
 
 bool
@@ -465,22 +481,7 @@ Events::create_event(THD *thd, Event_parse_data *parse_data,
       binlog the create event unless it's been successfully dropped
     */
     if (!dropped)
-    {
-      /* Binlog the create event. */
-      DBUG_ASSERT(thd->query() && thd->query_length());
-      String log_query;
-      if (create_query_string(thd, &log_query))
-      {
-        sql_print_error("Event Error: An error occurred while creating query string, "
-                        "before writing it into binary log.");
-        /* Restore the state of binlog format */
-        thd->current_stmt_binlog_row_based= save_binlog_row_based;
-        DBUG_RETURN(TRUE);
-      }
-      /* If the definer is not set or set to CURRENT_USER, the value of CURRENT_USER 
-         will be written into the binary log as the definer for the SQL thread. */
-      ret= write_bin_log(thd, TRUE, log_query.c_ptr(), log_query.length());
-    }
+      ret= event_write_bin_log(thd, TRUE);
   }
   pthread_mutex_unlock(&LOCK_event_metadata);
   /* Restore the state of binlog format */
@@ -602,9 +603,7 @@ Events::update_event(THD *thd, Event_parse_data *parse_data,
       if (event_queue)
         event_queue->update_event(thd, parse_data->dbname, parse_data->name,
                                   new_element);
-      /* Binlog the alter event. */
-      DBUG_ASSERT(thd->query() && thd->query_length());
-      ret= write_bin_log(thd, TRUE, thd->query(), thd->query_length());
+      ret= event_write_bin_log(thd, FALSE);
     }
   }
   pthread_mutex_unlock(&LOCK_event_metadata);