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[Xen-devel] Re: [PATCH resend] allow connecting to xenconsole from remot

To: Muli Ben-Yehuda <muli@xxxxxxxxxx>
Subject: [Xen-devel] Re: [PATCH resend] allow connecting to xenconsole from remote hosts
From: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Date: Tue, 26 Sep 2006 20:47:11 +0100
Cc: Jimi Xenidis <jimix@xxxxxxxxxxxxxx>, xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx>, Anthony Liguori <anthony@xxxxxxxxxxxxx>, Orran Y Krieger <okrieg@xxxxxxxxxx>
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On 26/9/06 7:50 pm, "Muli Ben-Yehuda" <muli@xxxxxxxxxx> wrote:

>> I don't believe such a problem exists with the current console code.
>> We only write() to the tty_fd if it is in the set of writefds after the
>> select() call in handle_io().
> Hmm? you're looking at the console daemon code and referring to the
> pty between the console daemon and client. I'm talking about the
> console client and referring the to other fd in use, which is either
> stdin/stdout (tty mode) or a socket (--remote mode). Sorry if I wasn't
> clear before - the buffering on the console client side isn't
> necessary between the daemon and the client, it's necessary between
> the client and the "outside world". The code buffers both fds since
> it's simpler than special casing one of them.

Oops. Okay, I'll take another look but couldn't you simply only read from
the source fd if you have write space in the destination fd? Ultimately
you'll fill the ring buffer and need to apply feedback to the data sender
anyway (by not reading from the fd)? So why have the buffer at all?

I guess I considered this patch as being to the daemon because isn't that
really where it would make most sense (e.g., a domain config option asking
console to be exported via a TCP port, which then causes xend to pass
appropriate options to the console daemon)?

 -- Keir

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