nvi dying with "Resource temporarily unavailable"

[Stephen McKay]

On Saturday, 9th August 2003, Doug White wrote:

>On Fri, 8 Aug 2003, Stephen McKay wrote:
>
>> >Stephen McKay wrote:
>> >> Since I upgraded to FreeBSD 4.8 (from 4.5) I've noticed occasional failures
>> >> of nvi.  It will suddenly die as a key is pressed, emitting:
>> >>
>> >> Error: input: Resource temporarily unavailable
>
>We went round and round on irc about this a few weeks back.  We pinned it
>down to a bad error check in nvi.  Unfortunately the fix was non-obvious.
>There's a read() that needs to check for EAGAIN and loop back around on
>the read.  If someone wants to take a crack at this, the offending read()
>is at common/cl_read.c line 266.
>
>> Zsh, actually.  Long live zsh! :-)
>
>I'm running tcsh and was able to reproduce on a 4.6-REL box a while back.
>The shell doesn't appear to have a bearing.

You almost had me convinced until I got this extraordinary result:

$ cat
cat: stdin: Resource temporarily unavailable
$

Never seen the like in all my born days.

I'm running zsh 3.1.9 on FreeBSD 4.8-RELEASE.  /bin/cat is a simple program.
If it isn't working properly, there's a fault in zsh or the kernel.  I have
not upgraded zsh since July 2000.  That makes it a bug in the kernel.  What
else could it be?  At a stretch perhaps a bug in libc.  Nothing else comes
to mind.

Stephen.