pty/tty or signal strangeness, or grep/bsdgrep bug?

[Jeremy Chadwick]

On Tue, Oct 23, 2012 at 10:42:47PM +0200, Ed Schouten wrote:
> Hi Kostik,
> 
> 2012/10/23 Konstantin Belousov <kostikbel at gmail.com>:
> > This is reproducable with the cat(1) as well. The telling part is that
> > the backgrounded process stays on the "ttyin" cv. The code for e.g.
> > tty read currently is structured as follows:
> >         check for background process reading from CTTY, send SIGTTYIN
> >         loop {
> >                 sleep waiting for input
> >                 process input
> >         }
> > The problem is that the SIGCONT does not remove the sleeping process from
> > the sleep queue, so the sleep is not interrupted with error. Instead, the
> > process is woken up later when input is available.
> >
> > Old tty code did the recheck for background state inside the loop after
> > the sleep.
> 
> Exactly. Was just debugging this as well and came to the same
> conclusion. Will try to come up with a decent patch tomorrow evening.
> 
> Thanks for reporting the issue!

No problem folks.  Would you like me to file a PR for this so we can
track it/for historical purposes?

-- 
| Jeremy Chadwick                                   jdc at koitsu.org |
| UNIX Systems Administrator                http://jdc.koitsu.org/ |
| Mountain View, CA, US                                            |
| Making life hard for others since 1977.             PGP 4BD6C0CB |