DMARC-Filter: OpenDMARC Filter v1.4.2 delorie.com 4B9DJiIA816694
Authentication-Results: delorie.com; dmarc=pass (p=none dis=none) header.from=cygwin.com
Authentication-Results: delorie.com; spf=pass smtp.mailfrom=cygwin.com
DKIM-Filter: OpenDKIM Filter v2.11.0 delorie.com 4B9DJiIA816694
Authentication-Results: delorie.com;
	dkim=pass (1024-bit key, unprotected) header.d=cygwin.com header.i=@cygwin.com header.a=rsa-sha256 header.s=default header.b=hOoxx/AY
X-Recipient: archive-cygwin AT delorie DOT com
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org A9E35385841C
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cygwin.com;
	s=default; t=1733750383;
	bh=K+MUlx0uo6chanfZ9okVOQfZKSHT+Tt2397oM0BTSf0=;
	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=hOoxx/AYr+27p7rol0IYfISQiq699r3iCOwHrVEqPKVf5zbdMJ57K3d4HI737KHMa
	 v7KcqsHma0B4dNtmP6up0NUJVkQNgA/NhZMZhknhMvfsUtt1xTkKl1DX5v2lOiyEmh
	 5D5wnsJLsqpAAXxafGoCQ9DzQ0/RZ5XQTk0F1yZY=
X-Original-To: cygwin AT cygwin DOT com
Delivered-To: cygwin AT cygwin DOT com
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 47D5A385828E
Date: Mon, 9 Dec 2024 14:17:58 +0100
To: cygwin AT cygwin DOT com
Subject: Re: cygpath and unc paths
Message-ID: <Z1buBnm2WlNEG8t1@calimero.vinschen.de>
Mail-Followup-To: cygwin AT cygwin DOT com
References: <ee626000-a159-4482-a897-da725f02b28c AT kircheis DOT it>
 <Z1bYfmvPYc6yFEJr AT calimero DOT vinschen DOT de>
 <053d21b3-ee11-4858-a60d-54cd154fd98c AT kircheis DOT it>
MIME-Version: 1.0
Content-Disposition: inline
In-Reply-To: <053d21b3-ee11-4858-a60d-54cd154fd98c@kircheis.it>
X-BeenThere: cygwin AT cygwin DOT com
X-Mailman-Version: 2.1.30
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>
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
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>

On Dec  9 13:47, Federico Kircheis via Cygwin wrote:
> On 09/12/2024 12.46, Corinna Vinschen via Cygwin wrote:
> > On Dec  6 13:23, Federico Kircheis via Cygwin wrote:
> > > Hello,
> > > 
> > > was it considered to add a flag to cygpath to output a path in unc format?
> > 
> > No.  But it wouldn't be much work.
> 
> It would be very nice if it ever happens.
> 
> > > For example, the folder
> > > 
> > > C:\test.
> > > 
> > > cannot be accessed from many Windows applications (powershell and cmd
> > > included) because of the trailing dot, while cygwin has no issue creating,
> > > accessing and deleting such files/folders.
> > > 
> > > Using an unc path
> > > 
> > > \\?\C:\test.
> > > 
> > > solves the issue for some programs, but cygpath currently misses an option
> > > for creating such path.
> > 
> > As a workaround you can just prepend the long path prefix:
> > 
> >    echo -n '\\?\'; cygpath ...
> 
> Which is what I'm doing, plus special-casing
> 
> 1)
> root path, like C:\ , because for whatever reason \\?\C:\ is not valid, it
> has to be a subfolder (and trying to trick it with \\?\C:\\ does not work
> either).

In which scenario?  \\?\C:\ is just the same as \??\C:\ in NT speak, and
that's a perfectly valid directory path.

> 2)
> unmounted network drives (\\server\path)

Yeah, those have a different prefix:

  \\?\UNC\server\share

> I'm not sure how a --unc should handle those cases.
> For all things I have in mind, not appending \\?\ is preferred, but someone
> might expect a hard error.
> 
> Either way, it is another reason why it makes sense for cygpath to handle
> those cases, currently I have to parse it's output before prepending '\\?\'.

I'll take a look.

> > > Notice that creating a dos path leads to an error.
> > 
> > I don't understand. Creating which DOS path with which application?
> 
> I meant that it is not possible to create a DOS path to C:\test., thus using
> a dos path is not a viable workaround to unc:
> 
> ----
> > cd 'C:/test.'
> > cygpath -ws .
> cygpath: cannot create short name of .
> ----

Don't use -s, it's just for the old short name style of DOS paths.
Nobody should actually need this nowadays, and sometimes short paths
don't even exist.  It's a functionality inside the FS driver, afaik, and
it can be switched off in the system.

In your example, standard filenames work:

  $ cd /cygdrive/c
  $ mkdir test.
  $ cd test.
  $ cygpath -ws .
  cygpath: cannot create short name of C:\test.
  $ cygpath -wa .
  C:\test.


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