WIP: plpgsql source code obfuscation

Hello

this patch define new function flag - OBFUSCATE. With this flag
encrypted source code is stored to probin column. Password is stored
in GUC_SUPERUSER_ONLY item - it is similar security like SQL Server
does (where privileged users can access system tables with source code
or can use debugger).

ToDo: Dump

Sample:

postgres=# show obfuscator_password;
obfuscator_password
-----------------------
moje supertajne heslo
(1 row)

postgres=# \x
Expanded display is on.
postgres=# create or replace function fx() returns int as $$begin
return -1; end; $$ language plpgsql;
CREATE FUNCTION
postgres=# \df+ fx
List of functions
-[ RECORD 1 ]-------+-----------------------
Schema | public
Name | fx
Result data type | integer
Argument data types |
Volatility | volatile
Owner | bob
Language | plpgsql
Source code | begin return -1; end;
Description |

postgres=# ALTER FUNCTION fx() obfuscate;
NOTICE: begin return -1; end;
ALTER FUNCTION
postgres=# \df+ fx
List of functions
-[ RECORD 1 ]-------+---------
Schema | public
Name | fx
Result data type | integer
Argument data types |
Volatility | volatile
Owner | bob
Language | plpgsql
Source code | -
Description |

postgres=# select fx();
-[ RECORD 1 ]
fx | -1

postgres=# create or replace function fx() returns int as $$begin
return -1; end; $$ language plpgsql obfuscate;
CREATE FUNCTION
postgres=# select fx();
-[ RECORD 1 ]
fx | -1

postgres=# \df+ fx
List of functions
-[ RECORD 1 ]-------+---------
Schema | public
Name | fx
Result data type | integer
Argument data types |
Volatility | volatile
Owner | bob
Language | plpgsql
Source code | -
Description |

postgres=# select * from pg_proc where proname = 'fx';
-[ RECORD 1 ]--+----------------------------------------------------------------------------
proname | fx
pronamespace | 2200
proowner | 16385
prolang | 16421
procost | 100
prorows | 0
proisagg | f
prosecdef | f
proisstrict | f
proretset | f
provolatile | v
pronargs | 0
prorettype | 23
proargtypes |
proallargtypes |
proargmodes |
proargnames |
prosrc | -
probin |
\231\003_\266\361\214}\231\240L/\020\232\036c\234\315P\236\266I\370\324\222
proconfig |
proacl |

[pavel(at)okbob-bb ~]$ psql -U bob postgres
Welcome to psql 8.3RC2, the PostgreSQL interactive terminal.

Type: \copyright for distribution terms
\h for help with SQL commands
\? for help with psql commands
\g or terminate with semicolon to execute query
\q to quit

postgres=> \x
Expanded display is on.
postgres=> show obfuscator_password;
ERROR: must be superuser to examine "obfuscator_password"
postgres=> select fx();
-[ RECORD 1 ]
fx | -1

postgres=> \df+ fx
List of functions
-[ RECORD 1 ]-------+---------
Schema | public
Name | fx
Result data type | integer
Argument data types |
Volatility | volatile
Owner | bob
Language | plpgsql
Source code | -
Description |

postgres=> select * from pg_proc where proname = 'fx';
-[ RECORD 1 ]--+----------------------------------------------------------------------------
proname | fx
pronamespace | 2200
proowner | 16385
prolang | 16421
procost | 100
prorows | 0
proisagg | f
prosecdef | f
proisstrict | f
proretset | f
provolatile | v
pronargs | 0
prorettype | 23
proargtypes |
proallargtypes |
proargmodes |
proargnames |
prosrc | -
probin |
\231\003_\266\361\214}\231\240L/\020\232\036c\234\315P\236\266I\370\324\222
proconfig |
proacl |