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Re: Still testing needed: New passwd/group AD/SAM integration

On Apr 10 14:20, Eric Blake wrote:
> On 04/10/2014 01:04 PM, Corinna Vinschen wrote:
> > A local cygwin user told me that the users in their company would
> > probably be confused by the '+ or, FWIW, any other non-backslash char,
> > because they were drilled to see and use usernames always in domain\name
> > form, or even in domain\\user form when logging in to Linux.
> > 
> > I like slashes a lot more for obvious reasons.  But maybe, and that
> > wouldn't be too hard to implement, we could accept account names with
> > slash and with backslash, just as we do with pathnames.  Output of
> > usernames would be with slashes, of course.
> POSIX says:
> [...]
> In short, in POSIX systems, user names are solely from the set
> [-_.a-zA-Z0-9]; which excludes +, \, or any other separator we come up
> with.  I'm fine with using a non-portable character (this is, after all,
> a cygwin extension of how to map Windows user names to a Linux emulation
> environment).  But keeping in mind the rules on tilde expansion,
> ~a+b/file
> can undergo tilde expansion for username 'a+b', but
> ~a\\b/file
> cannot do so, because the \ is necessarily always quoted.  There is no
> way to get tilde expansion to work for a username containing a shell
> metacharacter, which frowns on quite a few otherwise useful characters,
> including \.
> Worse, the thought of using / as the separator gives me the willies - it
> is BOUND to go wrong.  The expression
> ~a/b/file
> is NOT requesting 'file' within user 'a/b's home, but 'b/file' within
> user 'a's home.

This is a really good point.  This effectively eliminates slash from
the picture and the backslash reduces usability a lot, it seems.

So we might actually be better off by sticking to a configurable
separator char and default '+'?

What bugs me a bit is what this means for applications which expect
fixed usernames.  Sshd, for instance, expects the fixed username
"sshd" right now when using privilege separation.  I discussed this
with the OpenSSH devs, and they understand the problem, but they think
this should be handled by a Cygwin-specific function.  So there's some
extra work in it for me to get OpenSSH up to speed with this change,
but I fear I'm not the only one.  The more configurable stuff like this
is, the more complicated it gets maintaining some packages.


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

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