talloc issues

[tridge at samba.org]

Hi Michael,

 > I am deliberately not going into technical details
 > since I wanted to emphasize this superficial higher level
 > point of view of the callers.

The technical details really do matter. As the example I gave shows,
the proposals from Sam can create security holes in existing code that
followed the API documentation as given. Regardless of the high level
aspirations of the proposed changes we can't just ignore
this. Auditing the entire code base for such a change is an enormous
task, and it isn't a task that anyone has volunteered to do. 

I also don't think a code inspection audit will be sufficient - we
need a programmatic way of finding all existing use cases that are
deprecated.

That is why I added the location variable to the talloc reference
structure, so that when code hit a situation that has changed we get a
very clear message that allows for a quick fix. With the changes
proposed by Sam and the patches in Metze's tree we would instead
either get an abort() or we would get code dereferencing memory that
has been freed. Both are not good outcomes.

Cheers, Tridge