Oracle代码封装工具和DBMS_DDL包的使用
The WRAP Utility and the DBMS_DDL Package
On occasion it is necessary to hide (obfuscate) your PL/SQL source code. Traditionally this has been done using the WRAP utility, but Oracle 10g Release 2 also allows this to be done dynamically using the DBMS_DDLpackage. This article presents examples of both methods of PL/SQL source obfuscation.
The WRAP Utility
The wrap utility is a command line utility that obfuscates the contents of a PL/SQL source file. The syntax for the wrap utility is shown below.
wrap iname=input_file [oname=output_file]
The iname parameter specifies the source file, while the oname parameter specifies the destination file. If the destination file is not specified it defaults to the source file name with a ".pld" extension.
To see how the wrap utility works we must create a dummy source file called get_date_string.sql with the following contents.
CREATE OR REPLACE FUNCTION get_date_string RETURN VARCHAR2 AS BEGIN RETURN TO_CHAR(SYSDATE, 'DD-MON-YYYY'); END get_date_string; /
We can then run the two variants of the wrap utility, specifying our source file.
wrap iname=get_date_string.sql PL/SQL Wrapper: Release 10.2.0.1.0- Production on Wed Oct 05 10:54:14 2005 Copyright (c) 1993, 2004, Oracle. All rights reserved. Processing get_date_string.sql to get_date_string.plb wrap iname=get_date_string.sql oname=get_date_string_wrap.sql PL/SQL Wrapper: Release 10.2.0.1.0- Production on Wed Oct 05 10:55:01 2005 Copyright (c) 1993, 2004, Oracle. All rights reserved. Processing get_date_string.sql to /tmp/get_date_string_wrap.sql
Notice that the output file name is defaulted as expected when it is not specified on the command line. The resulting output files contain the wrapped code which is listed below.
CREATE OR REPLACE FUNCTION get_date_string wrapped a000000 b2 abcd abcd abcd abcd abcd abcd abcd abcd abcd abcd abcd abcd abcd abcd abcd 8 71 ae P29RDhRZX0orO0ED/mMF8i12Glkwg8eZgcfLCNL+XlquYvSuoVah8JbRPpdHDOrnwLK9spte 58d0wDO4dGUJuHSLwMAy/tKGCamhAs7G1hohrO/WTHaEcTKOd0xx9RBzc/XvN2dM6+zZPXLp r1UqFBwU/Sx2010pwUjXpqZCvywG /
The DBMS_DDL package for Dynamic Wrapping
The DBMS_DDL package contains three overloaded functions called WRAP, the simplest of which accepts a VARCHAR2 input parameter containing a PL/SQL CREATE OR REPLACE statement and returns the obfuscated PL/SQL, which can be written to a file or stored in a table. The following example shows how the basic WRAP function is used from PL/SQL.
SET SERVEROUTPUT ON SIZE UNLIMITED
DECLARE
l_source VARCHAR2(32767);
l_wrap VARCHAR2(32767);
BEGIN
l_source := 'CREATE OR REPLACE FUNCTION get_date_string RETURN VARCHAR2 AS' ||
'BEGIN ' ||
'RETURN TO_CHAR(SYSDATE, ''DD-MON-YYYY''); ' ||
'END get_date_string;';
l_wrap := SYS.DBMS_DDL.WRAP(ddl => l_source);
DBMS_OUTPUT.put_line(l_wrap);
END;
/
CREATE OR REPLACE FUNCTION get_date_string wrapped
a000000
b2
abcd
abcd
abcd
abcd
abcd
abcd
abcd
abcd
abcd
abcd
abcd
abcd
abcd
abcd
abcd
8
6f
aa
mV4eMSJ8EqqgErJT91l6UZ0pdDUwgyr6LZ5GfHSmUPiJfkEObQpeDb6D7glajI+ONulxdqC1
0HvOPP4eJpQs5zxsKXpj6XL1
fvieXyWCr3BTzXTqcGYhfXrtqDVPztR/o+9UZ8l5OijDSsRW
ZPv6rISzFyqeEsCBweFUFyxd
PL/SQL procedure successfully completed.
SQL>
This works fine for PL/SQL source that is less than or equal to 32K in size, but the VARCHAR2 input parameter means it can't cope with source larger than this. Fortunately the other overloads of this function allow us to work with source greater than 32K in size.
DBMS_DDL.WRAP( ddl DBMS_SQL.VARCHAR2S, lb PLS_INTEGER, ub PLS_INTEGER) RETURN DBMS_SQL.VARCHAR2S; DBMS_DDL.WRAP( ddl DBMS_SQL.VARCHAR2A, lb PLS_INTEGER, ub PLS_INTEGER) RETURN DBMS_SQL.VARCHAR2A;
In both overloads the source is passed in and out using an associative array (index-by table). The difference between the two is that the DBMS_SQL.VARCHAR2S type is limited to 256 bytes per line, while theDBMS_SQL.VARCHAR2A type can hold a maximum of 32K per line. The following example uses the DBMS_SQL.VARCHAR2A version to shows how these overloads work.
SET SERVEROUTPUT ON SIZE UNLIMITED
DECLARE
l_source DBMS_SQL.VARCHAR2A;
l_wrap DBMS_SQL.VARCHAR2A;
BEGIN
l_source(1) := 'CREATE OR REPLACE FUNCTION get_date_string RETURN VARCHAR2 AS ';
l_source(2) := 'BEGIN ';
l_source(3) := 'RETURN TO_CHAR(SYSDATE, ''DD-MON-YYYY''); ';
l_source(4) := 'END get_date_string;';
l_wrap := SYS.DBMS_DDL.WRAP(ddl => l_source,
lb => 1,
ub => l_source.count);
FOR i IN 1 .. l_wrap.count LOOP
DBMS_OUTPUT.put_line(l_wrap(i));
END LOOP;
END;
/
CREATE OR REPLACE FUNCTION get_date_string wrapped
a000000
b2
abcd
abcd
abcd
abcd
abcd
abcd
abcd
abcd
abcd
abcd
abcd
abcd
abcd
abcd
abcd
8
6f
aa
mV4eMSJ8EqqgErJT91l6UZ0pdDUwgyr6LZ5GfHSmUPiJfkEObQpeDb6D7glajI+ONulxdqC1
0HvOPP4eJpQs5zxsKXpj6XL1
fvieXyWCr3BTzXTqcGYhfXrtqDVPztR/o+9UZ8l5OijDSsRW
ZPv6rISzFyqeEsCBweFUFyxd
PL/SQL procedure successfully completed.
SQL>
In addition to the WRAP functions, the DBMS_DDL package also contains three overloaded procedures called CREATE_WRAPPED. These procedure have the same parameter lists as the three WRAP function overloads, and are used to wrap and compile the specified source. The following example shows how the DBMS_SQL.VARCHAR2A version is used.
SET SERVEROUTPUT ON SIZE UNLIMITED
DECLARE
l_source DBMS_SQL.VARCHAR2A;
l_wrap DBMS_SQL.VARCHAR2A;
BEGIN
l_source(1) := 'CREATE OR REPLACE FUNCTION get_date_string RETURN VARCHAR2 AS ';
l_source(2) := 'BEGIN ';
l_source(3) := 'RETURN TO_CHAR(SYSDATE, ''DD-MON-YYYY''); ';
l_source(4) := 'END get_date_string;';
SYS.DBMS_DDL.CREATE_WRAPPED(ddl => l_source,
lb => 1,
ub => l_source.count);
END;
/
PL/SQL procedure successfully completed.
SET PAGESIZE 100
SELECT text
FROM user_source
WHERE name = 'GET_DATE_STRING'
AND type = 'FUNCTION';
TEXT
------------------------------------------------------------------------
FUNCTION get_date_string wrapped
a000000
b2
abcd
abcd
abcd
abcd
abcd
abcd
abcd
abcd
abcd
abcd
abcd
abcd
abcd
abcd
abcd
8
6f aa
mV4eMSJ8EqqgErJT91l6UZ0pdDUwgyr6LZ5GfHSmUPiJfkEObQpeDb6D7glajI+ONulxdqC1
0HvOPP4eJpQs5zxsKXpj6XL1fvieXyWCr3BTzXTqcGYhfXrtqDVPztR/o+9UZ8l5OijDSsRW
ZPv6rISzFyqeEsCBweFUFyxd
1 row selected.
SQL>
The CREATE_WRAPPED procedures are the equivalent of passing the wrapped source returned from the WRAP function into an EXECUTE IMMEDIATE or DBMS_SQL.PARSE call, but they are optimized to give better performance.
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present by dylan.
