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From: Derek Fawcus <dfawcus+lists-tuhs@employees.org>
To: tuhs@minnie.tuhs.org
Subject: Re: [TUHS] sockets (was Re: First appearance of named pipes)
Date: Tue, 24 Mar 2020 10:47:10 +0100
Message-ID: <20200324094710.GB83316@clarinet.employees.org> (raw)
In-Reply-To: <20200323084943.GA341861@straylight.m.ringlet.net>

On Mon, Mar 23, 2020 at 10:49:43AM +0200, Peter Pentchev wrote:
> On Mon, Mar 09, 2020 at 05:22:57PM -0600, Grant Taylor via TUHS wrote:
> > On 3/8/20 9:13 AM, Derek Fawcus wrote:
> > > Now what would have been useful is a way to have distinct fd's for the
> > > local read and write end of (e.g.) a TCP socket - such that one
> > > direction could be closed w/o closing the other.
> > 
> > I believe that this can be done, now.  At least I've read that it's possible
> > for one end to close (FIN) a TCP connection without the other end also
> > closing.  Thus you end up with the one-way data flow that is still ACKed the
> > way that TCP does.
> 
> Yep, in the next sentence Derek mentioned "dispense with shutdown",
> meaning the shutdown(2) syscall that does exactly that. What he meant
> was, wouldn't it be nice to be able to do that with close(2) instead?

Quite.

One point being that one could fork/exec a program with those fd's attached
to stdin/stdout and it could operate as a normal filter, w/o having to
understand it was using a socket.

(i.e. closing stdout [hence triggering a FIN], while still reading from stdin)

Plus various other games achievable by replumbing fd's.

DF

  reply index

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-06 22:44 [TUHS] First appearance of named pipes Noel Chiappa
2020-03-07 12:17 ` Paul Ruizendaal
2020-03-07 13:29   ` Clem Cole
2020-03-07 16:39   ` Derek Fawcus
2020-03-08  2:36     ` Rob Pike
2020-03-08  2:47       ` Larry McVoy
2020-03-08 13:07         ` Ralph Corderoy
2020-03-08 13:25           ` arnold
2020-03-08  3:06       ` Dave Horsfall
2020-03-08  7:16       ` arnold
2020-03-08 15:13       ` [TUHS] sockets (was Re: First appearance of named pipes) Derek Fawcus
2020-03-09 23:22         ` Grant Taylor via TUHS
2020-03-09 23:44           ` Larry McVoy
2020-03-23  8:49           ` Peter Pentchev
2020-03-24  9:47             ` Derek Fawcus [this message]
2020-03-25 23:25               ` Grant Taylor via TUHS
2020-03-25 23:47                 ` Richard Salz
2020-03-26  0:11                   ` Grant Taylor via TUHS
2020-03-26  0:18                     ` Richard Salz
2020-03-26  1:08                       ` Grant Taylor via TUHS
2020-03-26  2:38                         ` Dave Horsfall
2020-03-26  3:08                           ` Rob Pike
2020-03-26  3:43                             ` George Michaelson
2020-03-26  4:11                           ` Grant Taylor via TUHS
2020-03-28 11:12                           ` Peter Pentchev
2020-03-28 11:14                             ` Peter Pentchev
2020-03-28 16:03                               ` Steffen Nurpmeso
2020-03-26  1:20                       ` Tony Finch
2020-03-27 10:51                   ` Derek Fawcus
2020-03-09 23:22 ` [TUHS] First appearance of named pipes Grant Taylor via TUHS
2020-03-10  7:29   ` arnold
2020-03-11  2:47     ` Grant Taylor via TUHS
2020-03-11  7:02       ` arnold
2020-03-10 13:49   ` Chet Ramey
2020-03-10 20:26     ` Dave Horsfall
2020-03-10 20:37       ` Chet Ramey
2020-03-11  2:51       ` Grant Taylor via TUHS
2020-03-08 23:09 [TUHS] sockets (was Re: First appearance of named pipes) Norman Wilson
2020-03-09 17:09 ` Tony Finch

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