Date: Wed, 17 Nov 2004 17:23:54 +0100 (CET)
From: Catalin Drula <Catalin.Drula@imag.fr>
To: <linux-kernel@vger.kernel.org>
Subject: Re: AF_UNIX sockets: strange behaviour
Message-ID: <Pine.GSO.4.33.0411171717530.8987-100000@horus.imag.fr>
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> Dick Johnson wrote:
>
> > Catalin Drula wrote:
> >
> > - there is a skb in the sk_receive_queue with a len of 13
> > - 6 bytes are read from it
> > - a skb with the remaining 7 bytes is requeued in sk_receive_queue
> > - on the next call to unix_stream_recvmsg, the sk_receive_queue is
> >  empty (!)
> >
> > Thus, this confirms the behaviour observed from userspace. Is this a
> > bug? Who could be removing the skb from the receive_queue?
>
> If you need STREAM behavior I think you need to use recv(),
> recvfrom(),or read().
>
> If you use recvmsg(), the "message" will be removed even it you
> haven't read it all. Note in the 'man' page description:
> "If the a message is too long to fit in the supplied buffer, excess
> bytes may be discarded depending upon the type of socket the message
> is being received from...

At first I used read() and then I tried recv() as well.

Catalin

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