From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mout.kundenserver.de (mout.kundenserver.de [212.227.126.131]) by sourceware.org (Postfix) with ESMTPS id D728F385E006 for ; Fri, 27 Mar 2020 11:21:18 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org D728F385E006 Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=cygwin.com Authentication-Results: sourceware.org; spf=fail smtp.mailfrom=corinna-cygwin@cygwin.com Received: from calimero.vinschen.de ([24.134.7.25]) by mrelayeu.kundenserver.de (mreue009 [212.227.15.167]) with ESMTPSA (Nemesis) id 1M7auL-1j9qQi1tYD-0082RS for ; Fri, 27 Mar 2020 12:21:17 +0100 Received: by calimero.vinschen.de (Postfix, from userid 500) id A82E4A80F96; Fri, 27 Mar 2020 12:21:15 +0100 (CET) Date: Fri, 27 Mar 2020 12:21:15 +0100 From: Corinna Vinschen To: cygwin@cygwin.com Subject: Re: WSL symbolic links Message-ID: <20200327112115.GL3261@calimero.vinschen.de> Reply-To: cygwin@cygwin.com Mail-Followup-To: cygwin@cygwin.com References: <294944bd-757e-4bb8-6bcc-ceb8d9190ef9@towo.net> <20200326110059.GG3261@calimero.vinschen.de> <901e1c08-46cb-555b-c0d0-5bf9c726b3ca@SystematicSw.ab.ca> <20200326195615.GJ3261@calimero.vinschen.de> <8e330046-97bb-ba3e-15dc-25aedf915d90@towo.net> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="QxIEt88oQPsT6QmF" Content-Disposition: inline In-Reply-To: <8e330046-97bb-ba3e-15dc-25aedf915d90@towo.net> X-Provags-ID: V03:K1:PgjvbVo+BozmzkT2aDZcPvUmRlZjiCXd+hqi7p3mcpjgaOJLKSK IBXYRiKqYua4DTW+kct/grg56JZX37Xm01VwX//ZriQfXRLf3TiSagNtKUUpSRs7QuYquZP VjG2VoTJwwB2zaDGbL9uFdxTVges0c13mzMLXrQNGHrjeLdHXLhVE5ONYPhfuTDW40+rZYZ qdAjX4f62uBpUZV6VMj5Q== X-UI-Out-Filterresults: notjunk:1;V03:K0:QyHIjBCPWAE=:6SSH0m1dkjOGOXYzroukTN j+odpog4hKslzq9QjYN6uL+aWE7y5cUN2CYv6Apx8+5hnuQa8FTIyD34I9MPEMB/xNeSfrWeF EtN4924esXt+re6/Bn6V46ThwdmHkVRSoMygUXao9wTTiMdk8gzbEtYa70zTEx3K3B6VRXWzl w4Pp9TpJYV3u4PKj7BFzGb9hr37yakPyC7kvGPPY37CSdIlY5SzD8tvFuuGk/6q8jNi5cb5bb ssxaPho9LEMEYQPhDCn7NQjAV3+nRdS0e9kWjGNCc4k5coMldiRGwtVf0mnB0GyzBUqXJgwwx c48YcbbNbYTnYCJ3LxxuavsVtPnhwF/axjBm6dy3rhRI0MHtwaU/jam3AFCg2bj49Z2Dn8PqJ fZfHc9WbeJFlCdb+TcbyxxTn2eqax07SY2aGKx0coFIEmOEu5NoCcsEX5Lp0CvqzY90NeOwTy XTQj3kccpsaSFFGUEDup2KagEiTh5X036iR6E7hcn8dEPrXOD4I7C4r3/aGJ+leutAjJO5kFb 9leFirznwSojw0A0Mjxlns6g8AwjdpOfxkjES8SemtwtiSMiZmUkf3QTHABIkIHNvA5Fw7z6Q VMkVvbWzNkLgO0lskZtQ68zXRj1Wxvl7+5AzkoIuAAars23c4DzROE0Z5sW4eJCqQwIV6qm8l pH0nw0xoiTrI2etKtdcybUPiFX/ICwSui2j79zyMiqEUNKtTgNY4CHen7OyWGoNvolxGMQyqe cYGyO2AMofH8cpvlf5/APNXIl0tqKTxr3bBXkPzoJE9EN6xzkDPEJI4mVEHZhWLtWnDtOtrQN 854vu1pEN9vH6y7VsCYcoS+XsTKKbrK57uD6TwKpkfPoLJkohHA4Q5G2NTGQu942QywTqHf X-Spam-Status: No, score=-82.3 required=5.0 tests=BAYES_00, BODY_8BITS, GARBLED_BODY, GOOD_FROM_CORINNA_CYGWIN, JMQ_SPF_NEUTRAL, KAM_DMARC_STATUS, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_NEUTRAL, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: cygwin@cygwin.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: General Cygwin discussions and problem reports List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 27 Mar 2020 11:21:20 -0000 --QxIEt88oQPsT6QmF Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mar 27 00:52, Thomas Wolff wrote: > Am 26.03.2020 um 20:56 schrieb Corinna Vinschen: > > This is a reparse point tag different from the normal Windows symlink > > reparse point tag, 0xa000000c. Searching for this value shows this > > is defined in ntifs.h as IO_REPARSE_TAG_LX_SYMLINK. > >=20 > > Unfortunately I don't see a definition of the reparse point data for > > that reparse point type. > >=20 > > In your examples the data part looks like a 4 byte int value, being 2 in > > both of your examples, maybe a file type, followed by the path in > > multibyte, no trailing \0. > >=20 > > Unfortunately, in both cases the path is relative, just the file name it > > points to. To get more information, could one of you two please create > > a few more symlinks? > >=20 > > - A symlink pointing to a local path, given in absolute path syntax. > > I assume the path will be in POSIX syntax, contain slashes, but it > > would be helpful to see it. > >=20 > > - A symlink with a target path pointing to a remote file (what syntax > > does this use?) > >=20 > > - Last but not least, could you please create a symlink pointing to a > > target with a non-ASCII char, e. g., some german umlaut? > Not sure what kind of remote you'd like to see. I have a 'net use' > (cifs/smbfs) mounted drive but couldn't mount it in WSL. Otherwise: >=20 > > wsl -d Ubuntu ls -l link* > lrwxrwxrwx 1 towo towo=C2=A0 4 Mar 27 00:31 link -> file > lrwxrwxrwx 1 towo towo 15 Mar 27 00:31 link-abs -> /mnt/c/tmp/file > lrwxrwxrwx 1 towo towo=C2=A0 5 Mar 27 00:39 link-foo -> f=C3=B6=C3=B6 > lrwxrwxrwx 1 towo towo 16 Mar 27 00:39 link-foo-abs -> /mnt/c/tmp/f=C3=B6= =C3=B6 > > rd-reparse '\??\C:\tmp\link' ; echo > ReparseTag:=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 0= xa000001d > ReparseDataLength:=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0 8 > Reserved:=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 0 > 02 00 00 00 66 69 6c 65 > > rd-reparse '\??\C:\tmp\link-abs' ; echo > ReparseTag:=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 0= xa000001d > ReparseDataLength:=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0 19 > Reserved:=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 0 > 02 00 00 00 2f 6d 6e 74 2f 63 2f 74 6d 70 2f 66 > 69 6c 65 > > rd-reparse '\??\C:\tmp\link-foo' ; echo > ReparseTag:=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 0= xa000001d > ReparseDataLength:=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0 9 > Reserved:=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 0 > 02 00 00 00 66 c3 b6 c3 b6 > > rd-reparse '\??\C:\tmp\link-foo-abs' ; echo > ReparseTag:=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 0= xa000001d > ReparseDataLength:=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0 20 > Reserved:=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 0 > 02 00 00 00 2f 6d 6e 74 2f 63 2f 74 6d 70 2f 66 > c3 b6 c3 b6 Thanks! In the meantime I could fix my problems with the Windows Store and was finally able to install WSL for further testing. See below. > If the link name itself contains non-ASCII, rd-reparse fails with > NtOpenFile: C0000034 Yeah, that's expected. The test app only handles filename with ASCII chars. > > It's questionable if supporting this new symlink type makes sense, but > > taking a closer look doesn't hurt, I guess. > Well, at least they should be deletable, I think. I debugged this now and I found that practically all problems, including the inability to delete the symlink, are a result of not being able to open the reparse point correctly as reparse point within Cygwin. So as not to destroy something important, Cygwin only opens reparse points as reparse points if it recognizes the reparse point type. Consequentially, all immediate problems go away, as soon as Cygwin recognizes and handles the symlink :) So I created a patch and pushed it. The latest developer snapshot from https://cygwin.com/snapshots/ contains this patch. Funny sidenote: Assuming you create symlinks pointing to files with non-UTF-8 chars, e. g., umlauts in ISO-8859-1, then the symlink converts *all* these chars to the Unicode REPLACEMENT CHARACTER 0xfffd. I assume this will also happen if you try to create the file with these chars in the first place, so it's not much of a problem. 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