On Wed, Jan 12, 2011 at 2:16 AM, Martijn van Oosterhout <klep...@svana.org> wrote: > On Tue, Jan 11, 2011 at 09:24:08PM -0500, Robert Haas wrote: >> commit 6c412f0605afeb809014553ff7ad28cf9ed5526b >> Author: Tom Lane <t...@sss.pgh.pa.us> >> Date: Sun May 1 18:56:19 2005 +0000 >> >> Change CREATE TYPE to require datatype output and send functions to have >> only one argument. (Per recent discussion, the option to accept multiple >> arguments is pretty useless for user-defined types, and would be a likely >> source of security holes if it was used.) Simplify call sites of >> output/send functions to not bother passing more than one argument. >> >> ...but I don't understand the motivation behind it. > > IIRC, the issue is that a type output function has to interpret a > Datum. Type output functions can also be called by users, so it is not > guarenteed that the given OID would actually match the type of the > Datum given. Hence the decision that the output function must be able > to determine itself what kind of Datum it is dealing with. > > Thought experiment: the datum is an integer, but the oid says it's a > pass-by-ref datum. Now the code may now to use the integer to derefence > an arbitrary place in memory.
I guess that begs the question of why we need to allow users to call type output functions directly. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
