Re: Functions in postgres

On Wed, Apr 05, 2000 at 12:04:49PM -0500, Victor Manuel Jaquez Leal wrote:
>
> Hi!

Hi back at ya.

>
> I know that with \df you can see the functions available in postgres, but
> there must be others not documented just like getpgusername().
>
> My question is if are there a more complete list of postgres'
> functions.  To be more specific I'm looking for a crypt function.
>

Then you're in luck. Not as much luck as if there was a built in, but
I've attached my implementation below. I stole a general boiler plate
function from someone else, and modified it to call crypt. The trickiest
part was generating random salt. I use it with these SQL statements:

CREATE FUNCTION "sqlcrypt" (text,text ) RETURNS text AS
'/usr/local/pgsql/data/sqlcrypt.so' LANGUAGE 'C';

CREATE FUNCTION "sqlcrypt" (text ) RETURNS text AS 'select
sqlcrypt($1,'''')' LANGUAGE 'SQL';

That way, I can say sqlcrypt('somestring') and it'll return a crypted
version of the string, with a randomly selected salt. I use it for
storing passwords for a web based login: for that, we check logins as
so:

SELECT * FROM "Personnel" WHERE "PerUsername" = 'RJReedstrom' AND
"PerPassword" = sqlcrypt('password',substr("PerPassword",1,2))

That will only return results if the password hashes match. It does expose
the cleartext of the password between the web server and postgres db:
That's not a problem for us, since they're on the same machine.

Ross
--
Ross J. Reedstrom, Ph.D., <reedstrm@rice.edu>
NSBRI Research Scientist/Programmer
Computer and Information Technology Institute
Rice University, 6100 S. Main St.,  Houston, TX 77005