Re: simply custom variables protection

"Pavel Stehule" <pavel(dot)stehule(at)hotmail(dot)com> writes:
>> How does a user protect a custom variable using your code? I don't see
>> any API that would allow that.

> Every module is responsibile for protectiong own custom variables. Only
> module knows if some variable needs protection. And after module
> inicialisation module can call ArmorCustomVariable function. From this
> moment only superuser can modify this custom variable. If it call
> ResetPGVariable() function before then default value is protected.

Well, that's the other problem with this approach: the variable is
protected only against changes occurring *after* ArmorCustomVariable
is called. Throwing away the existing value using ResetPGVariable is
surely undesirable if the existing value was in fact set by a superuser.
What's worse, I think it is a security hole, because ResetPGVariable's
effects can be rolled back by aborting the transaction in which the
module load occurs.

In any case we've now got a three-step rather than one-step method
for setting up a custom variable, with various interesting failure
modes if you do the steps in the wrong order. This is not a clean
solution.

regards, tom lane