Re: [PATCH].infokey feature and signal handling are broken

[AIDA Shinra]

> 
>     FreeBSD maintainers made this change:
snip 
> Meanwhile, any sort of explanation/documentation of what all these
> changes are doing would be helpful :).  For instance, what bug it's
> fixing ...

After "C-z", window resize and "fg", original info takes window size
as the size before "C-z" and scatters the screen. It means info should
recheck window size after "fg". The first change by FreeBSD maintainers
aimed to fix it but created another bug (C-z fg C-z q). The second
code is (probably) correct way.

The attached patch does more. It aims double signal safety in addition
to "C-z resize fg" fix. Signal handlers block another signal because
most functions don't seem to be reentrant. In fact my patch is no
sufficient because signals might be caught in unsafe context. I think
we should catch signals only in read(tty) and similar waits. But it's
paranoiac so I cared only double signals, which are more likely.