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Date: Mon, 2 Jun 2003 16:04:11 -0400
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Subject: sharing hd partition betw Linux and Cygwin
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From: somian AT adelphia DOT net (Soren Andersen)

Hello! Hithere folks.

I have been a temporary defector (so to speak) from Win32-running-cygwin
(bless it's heart) to Debian GNU/Linux (bigger blessings yet). As of the
end of last year no posts from me to cygwin. Missme, Chris? ;-) {decidedly
impish grin}.

Now I am back (no, not a Terminator(TM)-voice impression...) and so I
will send greetings along with a pesky question, and hopefully
sufficiently OT to boot, so that Chris et al will have no doubt that
it's really ME and not some well-behaved imposter.

There's little doubt in my mind that a handful of readers who will
eventually see this, are users of Linux as well as of Cygwin (in fact
TTBOMK this applies to cgf himself) and so I am hoping that something
useful might come out of my asking.

Preface: The Cygwin installation is recently updated and is running on top
of Win98SE (yes, sad).

Why: I want to share a CVS repository (local to my machine / localnet
only) between Cygwin and Linux. I want to be able to do checkout's,
commit's and all that from either OS env and share the same cvs ROOT
area on disk.

What: The entire logical partition is mounted on Linux using a mount
point /linms-common/ and the CVS area is under that
(/linms-common/SOMIANCVSROOT). A parallel arrangement (mountpoint
differing but that's all) exists under Cygwin-cvs. No problems exist (or
have manifested yet) under Cygwin, but under Linux I am having problems
with running CVS commands, and those problems are based on perms.

How (it fails): I cannot get CVS to run because it cannot write any
files to that dir.

I am trying to use the mount(1) options to the entry in my Linux
/etc/fstab "uid=NNN,gid=NNN" in order to correct for a potential problem
arising from differing users on the two systems. I have uid=[the numeric
UID on Win98-Cygwin] and gid=[my GID under Linux] in hopes that group
access rights are sufficient, but it turns out that they are not. By
default all files (dirs) mounted on this vfat - type filesystem under
Linux `mount' are set with perms rwxr--r-- so group members never have
'write' perms. From what I can tell from the docus for Linux 'mount',
there is no way to change this situation on a mount like
Win9x-vfat->(into)Linux.

Any insights? What does the setting of uid=NNN,gid=NNN actually DO on
linux? Is the target fs supposed to be treated as if those are the uid
and gid of the target fs's "owning" OS (in which case of course Linux
cannot possibly know about what gids and uids exist on that system), or
are the uid and gid of a user on the Linux system? Is there any harm to
be caused by making the uid= that of who I really am running as on the
Linux system (which, if there's no bad side, seems like it might fix the
problem) Oh, and ... any insights?

Finally, is there anything that I can do on the *Cygwin* side to change
the perms that Linux's `mount' "perceives" on the target filesystem? I
understand that everything relating to *nix-like perms on Win9x is a
complete kludge since there's no user-id -based access control on such a
lame platform, that has any real meaning or "bite". On WinNT-derived MS
platforms it might be a different story.

   Best Regards,
     Soren Andersen

-- 
See my OpenPGP key at https://savannah.gnu.org/people/viewgpg.php?user_id=6050
GnuPG public key fingerprint  | "Only when efforts to reform society have as
 BD26 A5D8 D781 C96B 9936     |  their point of departure the reformation of
 310F 0573 A3D9 4E24 4EA6     |  the inner life -- human revolution -- will
they lead us with certainty to a world of lasting peace and true human security."
                                -- Daisaku Ikeda

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