Harlan Stenn wrote:
> Danny wrote:
>> Harlan Stenn wrote:
>>> There is a good reason for the move_fd code.  Frank would probably know
>>> better, and he's on vacation for another 2-3 weeks' time.
> 
>> Actually I was the one that wrote it and yes there are good reasons for
>> doing it.
Yes, you wrote the initial version, I then refined that to cover
more coner cases and added a 28 line text to explain the reasons for the 
code. What information is missing ? Or are you looking at a version 
different from 4.2.4pX ?

> 
> Cool - thanks for letting me know those things.
> 
> Would you please *add* the good reasons to a comment in the code just
> before the definition of move_fd() when you get a chance?  There are
> *plenty* of undocumented cases where we do something for a good reason
> nobody can remember anymore.

Do you see the comment starting .. On Unix systems the stdio library... ?
This is supposed to be the explanation the the move_fd() implementation.

> 
>> However, if for some reason this causes a problem on his
>> particular O/S we can create a conditional macro to have it not use it.
> 
> And until somebody besides you knows the good reason for move_fd(),
> nobody else will know if disabling move_fd() for AIX will be a good
> thing or if it will trade one problem for another (in this case, the
> underlying reason for having move_fd()).

Good point ! That's why I'd rather like to find out what goes wrong
with move_fd() on AIX. We may either uncover a ntpd implementation bug,
an AIX spcialty or an AIX library bug.

> 
>>> I think it has to do with making sure there is room to open different sorts
>>> of files, and may only be important if one has refclocks.
>>>
>>> But it could be Bad to disable move_fd() in general for AIX.
>>>
>> We don't know the general case to be able to answer that one.
> 
> OK, so again, when the underlying reasons fo having move_fd() are
> documented (and therefore better known) in general, we have a chance of
> coming up with a better answer for this, too.
> 
>>> As for IPv6, are there any versions of AIX where IPv6 is working?
>> Yes, IPv6 does work on AIX. It's just that it's being confused by 6over4
>> and 4in6 and at least some versions of the O/S is not keeping the
>> address space separate. It should be running as a dual-stack or at least
>> not trying to play tricks with the address space.
> 
> OK, sounds to me like that is an instance of "not working", at least as
> far as we are concerned.
> 
> If there are known problems/issues with things like this, I would
> strongly request that people add this sort of information somewhere.  It
> could be the code, or it could be at http://support.ntp.org/Dev .
> 
> If we can figure out which versions of the OS do what, and if we can
> determine what OS version we have at runtime, we can have a single AIX
> executable DTRT depending on the OS verison (or patch level).
> 
> H

Frank

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