password change / table creation

There are two questions in the pgsql-admin mailing list which are very often
asked, but nobody seems to have a reasonable answer to these.
So I decided to post them here and I hope anyone can help me (and many
others) !

   - Can a PostgreSQL user change his own password without having     "usesuper" set to 't' in pg_shadow ?
     I think this should be possible with a PostgreSQL C function (or     PL/Tcl) which alters the "passwd" attribute
ofthe pg_shadow table and     after that copies the contents of this table to the pg_pwd ASCII file     (and generates
anempty pg_pwd.reload).     But I have no idea how to manipulate and copy tables within PostgreSQL     C functions.
 
     Does anybody know if there is already such a function or any other way     to achieve the above mentioned
functionality?
 

   - Can the Postgres superuser prevent a user from creating tables in any     database the user likes to ?
     It would be good to have a way to restrict the use of the "CREATE     TABLE" SQL statement so that a user can only
createtables in     databases he is explicitly allowed to.
 
     Does anyone have an idea how to solve this problem ?


If these two features are not yet implemented I would suggest to think about
implementing them, because I (and many other people) would consider them
as important, especially in practical use.

Please let me know !


Thank you very much
RP. Dumont