Fix for bug #6081 "Call to deprecated mysql_create_db() function crashes

server".

Altough mysql_create_db()/mysql_drop_db() API calls are deprecated
since 4.0, they should not crash server and should not stall connection
in case of errors. 


sql/sql_parse.cc:
  Handling of COM_CREATE_DB, COM_DROP_DB:
    mysql_create_db() requires from its second parameter to be non-zero.
    We also should call send_error() if mysql_create_db or mysql_drop_db
    return error (like we do it for SQL versions of these commands).
tests/client_test.c:
  Added test for bug #6081 "Execution of deprecated mysql_create_db()
  crashes server".

sql/sql_parse.cc

@@ -1556,6 +1556,7 @@ bool dispatch_command(enum enum_server_command command, THD *thd,
   case COM_CREATE_DB:				// QQ: To be removed
     {
       char *db=thd->strdup(packet), *alias;
+      HA_CREATE_INFO create_info;
 
       statistic_increment(com_stat[SQLCOM_CREATE_DB],&LOCK_status);
       // null test to handle EOM
@@ -1567,7 +1568,10 @@ bool dispatch_command(enum enum_server_command command, THD *thd,
       if (check_access(thd,CREATE_ACL,db,0,1,0))
 	break;
       mysql_log.write(thd,command,packet);
-      mysql_create_db(thd,(lower_case_table_names == 2 ? alias : db),0,0);
+      bzero(&create_info, sizeof(create_info));
+      if (mysql_create_db(thd, (lower_case_table_names == 2 ? alias : db),
+                          &create_info, 0) < 0)
+        send_error(thd, thd->killed ? ER_SERVER_SHUTDOWN : 0);
       break;
     }
   case COM_DROP_DB:				// QQ: To be removed
@@ -1588,7 +1592,9 @@ bool dispatch_command(enum enum_server_command command, THD *thd,
 	break;
       }
       mysql_log.write(thd,command,db);
-      mysql_rm_db(thd, (lower_case_table_names == 2 ? alias : db), 0, 0);
+      if (mysql_rm_db(thd, (lower_case_table_names == 2 ? alias : db),
+                      0, 0) < 0)
+        send_error(thd, thd->killed ? ER_SERVER_SHUTDOWN : 0);
       break;
     }
 #ifndef EMBEDDED_LIBRARY

tests/client_test.c

@@ -10541,6 +10541,33 @@ static void test_bug5315()
 }
 
 
+/*
+  Altough mysql_create_db(), mysql_rm_db() are deprecated since 4.0 they
+  should not crash server and should not hang in case of errors.
+
+  Since those functions can't be seen in modern API (unless client library
+  was compiled with USE_OLD_FUNCTIONS define) we use simple_command() macro.
+*/
+static void test_bug6081()
+{
+  int rc;
+  myheader("test_bug6081");
+
+  rc= simple_command(mysql, COM_DROP_DB, current_db,
+                     (ulong)strlen(current_db), 0);
+  myquery(rc);
+  rc= simple_command(mysql, COM_DROP_DB, current_db,
+                     (ulong)strlen(current_db), 0);
+  myquery_r(rc);
+  rc= simple_command(mysql, COM_CREATE_DB, current_db,
+                     (ulong)strlen(current_db), 0);
+  myquery(rc);
+  rc= simple_command(mysql, COM_CREATE_DB, current_db,
+                     (ulong)strlen(current_db), 0);
+  myquery_r(rc);
+}
+
+
 /*
   Read and parse arguments and MySQL options from my.cnf
 */
@@ -10851,6 +10878,7 @@ int main(int argc, char **argv)
     test_bug5194();         /* bulk inserts in prepared mode */
     test_bug5315();         /* check that mysql_change_user closes all
                                prepared statements */
+    test_bug6081();         /* test of mysql_create_db()/mysql_rm_db() */
     /*
       XXX: PLEASE RUN THIS PROGRAM UNDER VALGRIND AND VERIFY THAT YOUR TEST
       DOESN'T CONTAIN WARNINGS/ERRORS BEFORE YOU PUSH.