Date: Fri, 21 Mar 2003 04:14:03 +1100 (EST) From: Bruce Evans <bde@zeta.org.au> To: Luigi Rizzo <rizzo@icir.org> Cc: Peter Pentchev <roam@ringlet.net>, "" <net@FreeBSD.ORG>, Tristan Goode <tgoode@iprimus.com.au> Subject: Re: write(2) SIGPIPE on a closed socket? Message-ID: <20030321040924.G13725@gamplex.bde.org> In-Reply-To: <20030320082954.B15241@xorpc.icir.org> References: <20030319093002.GT468@straylight.oblivion.bg> <20030319013748.A84035@xorpc.icir.org> <20030319094506.GB27330@straylight.oblivion.bg> <20030319215212.V8375@gamplex.bde.org> <20030320082954.B15241@xorpc.icir.org>
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On Thu, 20 Mar 2003, Luigi Rizzo wrote:
> On Wed, Mar 19, 2003 at 10:27:57PM +1100, Bruce Evans wrote:
> ...
> <re. SIGPIPE handling>
> > % error = so->so_proto->pr_usrreqs->pru_sosend(so, to, &auio, 0, control,
> > % flags, td);
> > % if (error) {
> > % if (auio.uio_resid != len && (error == ERESTART ||
> > % error == EINTR || error == EWOULDBLOCK))
> > % error = 0;
> > % /* Generation of SIGPIPE can be controlled per socket */
> > % if (error == EPIPE && !(so->so_options & SO_NOSIGPIPE)) {
> > % PROC_LOCK(td->td_proc);
> > % psignal(td->td_proc, SIGPIPE);
> > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> > % PROC_UNLOCK(td->td_proc);
> > % }
> > % }
> >
> > This code seems to have an interesting version of mishandling short
> > i/o counts (auio.uio_resid != len && auio.ui_resid != 0). Short i/o
> > counts involving an interrupt are normally the only ones handled
> > correctly (by the ERESTART/EINTR/EWOULDBLOCK fixup). However, in the
> > case of EPIPE/SIGPIPE, we only notice the SIGPIPE after we do the
> > fixup, so we never do the fixup and always return an error instead of
> > the short i/o count.
>
> this is probably harmless because the pipe is gone anyways,
> so it matters little how many bytes have been written, right ?
Depends what was in the bytes that were written. Of course, with networks
even delivery of the bytes doesn't guarantee much.
Bruce
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