X-Recipient: archive-cygwin AT delorie DOT com
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 9E04C3857C66
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cygwin.com;
	s=default; t=1691575041;
	bh=h0Q8V9iTrZ3S4RVPLiP2gtdirsp/azlbtqTfLhprapU=;
	h=Date:To:Subject:References:In-Reply-To:List-Id:List-Unsubscribe:
	 List-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To:Cc:
	 From;
	b=gMC769emBo5PpQrPCKd57h1pRRwWUvgazlzxmIM+T5Uf+Povhs867V/xnghZ0aLdG
	 vX91rDWSW/5W+CL/5mYSJu6NmVs+jx2hXivgdW+MEbDAyyCCIg5PpNg2KKroTaj0eO
	 dxQXj04ZzSFJhadT/3/AW915WS+OcUCk1r2lDQuY=
X-Original-To: cygwin AT cygwin DOT com
Delivered-To: cygwin AT cygwin DOT com
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 1AE1D3858D20
Date: Wed, 9 Aug 2023 11:56:43 +0200
To: Martin Wege <martin DOT l DOT wege AT gmail DOT com>
Subject: Re: mkfifo: cannot set permissions of 'x.fifo': Not a directory
Message-ID: <ZNNi2//PUy0QPNa9@calimero.vinschen.de>
Mail-Followup-To: Martin Wege <martin DOT l DOT wege AT gmail DOT com>, cygwin AT cygwin DOT com
References: <CANH4o6O-8O-iMaHowDuy0y7H=pVfZ-3EvubDmTdjGVSST8FkAQ AT mail DOT gmail DOT com>
 <c8daacfa-b441-ebbb-90da-03318080479c AT Shaw DOT ca>
 <ZNFCjtiVOhpRYhHI AT calimero DOT vinschen DOT de>
 <CANH4o6P2fBmxvOZKVrrxDuMByHEMgs2qg14p710aUuLsFYG4rA AT mail DOT gmail DOT com>
 <ZNH62q/fs9Lt78dD AT calimero DOT vinschen DOT de>
 <CANH4o6Pjfsgijcf3rHEeB+YsVQTQYm8EvepwFVdj_PrKuP4NHA AT mail DOT gmail DOT com>
 <ZNNH0hbsCqH98ioK AT calimero DOT vinschen DOT de>
 <CANH4o6M-PGuzDRMy_dzgnwfGmVhcH_VSw-w91AWggctOa9TLWw AT mail DOT gmail DOT com>
MIME-Version: 1.0
Content-Disposition: inline
In-Reply-To: <CANH4o6M-PGuzDRMy_dzgnwfGmVhcH_VSw-w91AWggctOa9TLWw@mail.gmail.com>
X-BeenThere: cygwin AT cygwin DOT com
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: General Cygwin discussions and problem reports <cygwin.cygwin.com>
List-Unsubscribe: <https://cygwin.com/mailman/options/cygwin>,
 <mailto:cygwin-request AT cygwin DOT com?subject=unsubscribe>
List-Archive: <https://cygwin.com/pipermail/cygwin/>
List-Post: <mailto:cygwin AT cygwin DOT com>
List-Help: <mailto:cygwin-request AT cygwin DOT com?subject=help>
List-Subscribe: <https://cygwin.com/mailman/listinfo/cygwin>,
 <mailto:cygwin-request AT cygwin DOT com?subject=subscribe>
From: Corinna Vinschen via Cygwin <cygwin AT cygwin DOT com>
Reply-To: cygwin AT cygwin DOT com
Cc: Corinna Vinschen <corinna-cygwin AT cygwin DOT com>, cygwin AT cygwin DOT com
Content-Type: text/plain; charset="utf-8"
Errors-To: cygwin-bounces+archive-cygwin=delorie DOT com AT cygwin DOT com
Sender: "Cygwin" <cygwin-bounces+archive-cygwin=delorie DOT com AT cygwin DOT com>
Content-Transfer-Encoding: 8bit
X-MIME-Autoconverted: from base64 to 8bit by delorie.com id 3799vM8n011010

On Aug  9 11:12, Martin Wege via Cygwin wrote:
> On Wed, Aug 9, 2023 at 10:01 AM Corinna Vinschen
> <corinna-cygwin AT cygwin DOT com> wrote:
> >
> > On Aug  8 21:38, Martin Wege via Cygwin wrote:
> > > On Tue, Aug 8, 2023 at 10:20 AM Corinna Vinschen
> > > <corinna-cygwin AT cygwin DOT com> wrote:
> > > >
> > > > On Aug  7 23:14, Martin Wege via Cygwin wrote:
> > > > > Secondly, how are fifos, other device nodes and mknod implemented? You
> > > > > encode them as softlinks on ntfs?
> > > >
> > > > Not only on NTFS.  FIFOs on the disk are always created as symlinks
> > > > with a special target string, recognized by Cygwin.  No differece on
> > > > NFS.  Microsoft NFSv3 has no way to specify creating a "real" FIFO
> > > > on the remote filesystem.  It wouldn't make sense anyway, because
> > > > there's no way to share the FIFO across systems.
> > >
> > > So no Windows ioctl to do a mknod?
> >
> > Windows does not have provisions to store FIFOs on disk.  The closest
> > you get in Windows are Windows named pipes, and those are stored
> > non-permanently in a special, temporary filesystem inside the native NT
> > namespace.  Try this in Cygwin:
> >
> >   $ cd /proc/sys/Device/NamedPipe/    <-- trailing slash!
> >   $ ls -l
> >
> > FIFOs in the normal Windows filesystem are a Cygwin fake.
> 
> Maybe make pipes in Cygwin symlinks to /proc/sys/Device/NamedPipe/?

Why?  Windows Named Pipes don't act like UNIX FIFOs.

> > > What does a Linux/FreeBSD FIFO file look like, if you export that
> > > filesystem via NFSv3, and mount it via the native Windows NFSv3
> > > driver, and do a ls -l in Cygwin?
> >
> > It looks like a FIFO because MSFT NFSv3 exports the stat(2) info
> > verbatim:
> >
> > linux$ mkfifo blubb
> >
> > cygwin$ ls -l blubb
> > prw-r--r-- 1 corinna vinschen 0 Aug  8 10:22 blubb
> 
> Will cygwin treat this as a FIFO?

No.  Cygwin FIFOs != Unix FIFOs.

> Can cygwin set the 'p' flag via a magic ioctl?

No.  I don't understand your insistence to use FIFOs on NFS.  There is
no value in that, because you can't share them between systems anyway.

https://www.unix.com/unix-for-advanced-and-expert-users/10861-fifo-over-nfs.html
https://stackoverflow.com/questions/1038788/cant-write-to-fifo-file-mouted-via-nfs


Corinna

-- 
Problem reports:      https://cygwin.com/problems.html
FAQ:                  https://cygwin.com/faq/
Documentation:        https://cygwin.com/docs.html
Unsubscribe info:     https://cygwin.com/ml/#unsubscribe-simple