Re: patch: sockaddr instead of mbuf to carry addresses

[Alan Barrett <apb%cequrux.com@localhost>]

On Tue, 24 Mar 2015, Christos Zoulas wrote:
> | If it is better to increase the size of struct sockaddr_storage shoot me
> | a preferred updated structure definition and I'll go with that.
>
> I am not sure which is less of a pain to do... (binary compatibility?)

I like the idea of making struct sockaddr_storage the largest of
all the sockaddr_foo types.

sockaddr_storage is used in struct ifreq, which is used in a 
bunch of ioctls.  It is also mentioned in a few other places 
in /usr/include/**.  If we increased the size of struct 
sockaddr_storage, then we'd need to provide binary compatibility, 
which is tedious but not difficult in most cases.

The difficult cases are that struct sockaddr_storage is embedded 
in struct utmpx and struct lastlogx, which are stored on disk in 
/var/run/utmpx, /var/log/wtmpx, and /var/log/lastlogx.  I don't see an
easy way for a process reading the file to be able to tell whether it
uses the old or new struct sockaddr_storage.

--apb (Alan Barrett)