From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 53863 invoked by alias); 17 Dec 2018 18:50:59 -0000 Mailing-List: contact cygwin-help@cygwin.com; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: cygwin-owner@cygwin.com Mail-Followup-To: cygwin@cygwin.com Received: (qmail 53841 invoked by uid 89); 17 Dec 2018 18:50:58 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-1.9 required=5.0 tests=BAYES_00,FREEMAIL_FROM,HTML_MESSAGE,RCVD_IN_DNSWL_NONE,SPF_PASS autolearn=ham version=3.3.2 spammy=answered, H*c:PHrt, H*c:alternative, H*x:5.0 X-HELO: sonic308-3.consmr.mail.bf2.yahoo.com Received: from sonic308-3.consmr.mail.bf2.yahoo.com (HELO sonic308-3.consmr.mail.bf2.yahoo.com) (74.6.130.42) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Mon, 17 Dec 2018 18:50:55 +0000 Received: from sonic.gate.mail.ne1.yahoo.com by sonic308.consmr.mail.bf2.yahoo.com with HTTP; Mon, 17 Dec 2018 18:50:53 +0000 Date: Mon, 17 Dec 2018 19:22:00 -0000 From: "Simon Liesenfeld via cygwin" Reply-To: Simon Liesenfeld To: cygwin@cygwin.com Message-ID: <768216656.5669803.1545072652503@mail.yahoo.com> In-Reply-To: <20181217165741.GB28727@calimero.vinschen.de> References: <1823593702.5343751.1545034298027.ref@mail.yahoo.com> <1823593702.5343751.1545034298027@mail.yahoo.com> <20181217093428.GQ28727@calimero.vinschen.de> <20181217165741.GB28727@calimero.vinschen.de> Subject: Re: symbolic links on Paragon Linux File systems MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-IsSubscribed: yes X-SW-Source: 2018-12/txt/msg00159.txt.bz2 Hi Corinna, since you answered your own questionsI can better understand my own stupidi= ty.I have created now a hard and a soft link with a native linux,then I boo= ted Windows, started the paragon driver,then cygwin=C2=A0 programs as well = as any dos program perfectly=20 understood the links. Even if cygwin were able to understand its own links on paragon volumes,the= y would not be understood when running the volume by linux again.That does = not make sense. May be there is a command line option from paragonto create links. Thank you so much Corinna. On Monday, December 17, 2018, 5:57:43 PM GMT+1, Corinna Vinschen wrote:=20=20 =20 On Dec 17 10:34, Corinna Vinschen wrote: > On Dec 17 08:11, Simon Liesenfeld via cygwin wrote: > > Hi all > >=20 > > There is a commercial ext3-4 file system driver for windowsLinux File > > Systems f=C3=BCr Windows | Paragon Softwarewhich enable Windows to read= an > > write on native ext3-4 volumes.In General cygwin works perfectly on > > such volumes,even named pipes work, > > but Cygwin programs do not interprete those links correctly,which are > > created on such volumes.whilst symbolic links on native NTFS drives > > referring files on such volumeswork perfectly. > > $pwd/cygdrive/e > >=20 > > $ echo hallo > source > >=20 > > $ ln -s source sl > >=20 > > $ cat sl > > !=E2=96=92=E2=96=92source >=20 > Yes, we can't do that without special knowledge of the FS.=C2=A0 The defa= ult > symlinks on Cygwin are only evaluated correctly if the DOS SYSTEM > attribute is set.=C2=A0 The ext4 driver can't do that, obviously. >=20 > Are the native symlinks on an ext4 FS converted to NTFS symlinks > on the fly by the driver?=C2=A0 Are they visible as symlinks in Windows > or Cygwin? >=20 > If so, you could try setting the environment variable CYGWIN to contain > "winsymlinks:native".=C2=A0 This creates native Windows symlinks rather t= han > the special Cygwin POSIX symlinks.=C2=A0 If the driver is handling this > correctly, it should transparently convert them to ext4 symlinks and > they should just work. Answering my own questions: No, the driver does not handle symlinks gracefully *at all*. - Existing symlinks on the FS are handled as if they are simple files. =C2=A0 They are in no way identifiable as symlinks by any Windows client. =C2=A0 They supposedly only contain the name of the symlink target, which is =C2=A0 an arbitrary string.=C2=A0 No symlink marker or anything. - DOS file attributes don't work, so we can't use Cygwin's symlink =C2=A0 handling, not even by utilizing Windows shortcuts instead of Cygwin =C2=A0 symlinks. - Windows native symlinks and transparent conversion to and from ext4 =C2=A0 symlinks is not supported. - No ACL handling, not even to fake basic POSIX permissions, so we can't =C2=A0 change the permissions at all. I don't think it's worth to go to great length supporting Cygwin symlinks on this FS.=C2=A0 They won't be recognized by your Linux installation as symlinks anyway and we'd have to perform excessively slow checks just to recognize them. As a sidenote, the OSS project Ext2Fsd handles symlinks transparently via standard Windows functions.=C2=A0 With "CYGWIN=3Dwinsymlinks:native" you can generate real ext4 symlinks transparently.=C2=A0 Even the good old Cygw= in symlink works on Cygwin without programmatic intervention, albeit those won't be recognized as symlinks by Linux of course.=C2=A0 Unfortunately Ext2Fsd didn't learn to handle ext4 with the 64bit FS option set yet. 64bit is default for quite some time. Corinna --=20 Corinna Vinschen Cygwin Maintainer=20=20 -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple