Re: Microsoft Accounts (was Re: Problem with "None" Group on Non-Domain Members)

[Corinna Vinschen <corinna-cygwin at cygwin dot com>]

On May  6 13:01, Chris J. Breisch wrote:
> Corinna Vinschen wrote:
> >Other than that, I'm open to discuss the necessity(?) to override
> >the primary group by default.  But, in fact, I'm not sure this really
> >makes sense.  Linux systems default to creating a user-specific group
> >account and using that as the user's primary group for years.  The
> >Windows Account technique isn't quite as nice, but admittedly, it
> >does its job just as well.
> 
> Yes, I've experienced that on Linux, but I don't recall having these
> file permission issues there. Perhaps I just never noticed though.

No, it *is* different,  On Linux you get a user account called "Chris"
and a group account called "Chris", and they are different because users
and groups are totally different beasts on POSIX systems.  You can have
a user with uid 42 and a group with gid 42 and they are still different.

On Windows, users and groups are identified not by uid/gid, but by
their SID.  The SID is a unique value, but other than that, a SID can
be a user or a group and in lots of cases Windows doesn't care.
A group can be owner of a file and a user can be the group of the file,
it just doesn't matter to Windows.

The permission "problem" you're seeing is a result of that.  Your user
*and* your primary group are both your user's SID.  Therefore the same
account is user and primary group at the same time.  Therefore, if
the file is created, it gets created with an ACL with user and group
being the same account.  Therefore the POSIX translation of the user
and group permissions on the file are always the same.

Does this clear it up?


Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Maintainer                 cygwin AT cygwin DOT com
Red Hat

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