Date: Tue, 23 Oct 2012 22:42:47 +0200 From: Ed Schouten <ed@80386.nl> To: Konstantin Belousov <kostikbel@gmail.com> Cc: Jeremy Chadwick <jdc@koitsu.org>, freebsd-stable@freebsd.org, jhb@freebsd.org Subject: Re: pty/tty or signal strangeness, or grep/bsdgrep bug? Message-ID: <CAJOYFBDhDMwgPyWRrzj021eqN=meS3q2FfTi9=5xpVPcXrNxYg@mail.gmail.com> In-Reply-To: <20121023203928.GZ35915@deviant.kiev.zoral.com.ua> References: <20121023142703.GA79098@icarus.home.lan> <20121023203928.GZ35915@deviant.kiev.zoral.com.ua>
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Hi Kostik,
2012/10/23 Konstantin Belousov <kostikbel@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!
--
Ed Schouten <ed@80386.nl>
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