Corinna Vinschen corinna-cygwin@cygwin.com
Mon Nov 10 20:45:00 GMT 2014

On Nov 10 20:21, Christian Franke wrote:
> Corinna Vinschen wrote:
> >On Nov  7 21:51, Christian Franke wrote:
> >>Corinna Vinschen wrote:
> >>>>>In theory there should be only one option -l [machine], which prints the
> >>>>>local accounts of the current machine unprefixed (standalone machine) or
> >>>>>prefixed (domain machine), and always prefixed for a foreign machine.
> >>>>>The -L option can just go away.
> >>>>I disgree.
> >>>>
> >>>>Why not keep the old behavior of -l/-L for user names of current machine for
> >>>>those uses cases which rely on it?
> >>>You are always free to change the passwd/group files manually:
> >>>
> >>>   $ mkpasswd -l | sed -e 's/^[^:]*+//' > /etc/passwd
> >>Of course, and it is good that this is still possible. But this would
> >>require that all existing scripts relying on old behavior need to be
> >>changed.
> >>
> >>I still don't understand why this backward compatibility break of "mkpasswd
> >>-l" was mandatory.
> >>
> >>Most *-config scripts using "mkpasswd -l -u USER" may need to be changed.
> >Definitely.  The change is inevitable since most scripts using mkpasswd
> >or mkgroup do so to create entries in /etc/passwd and /etc/group.  But
> >this doesn't make sense anymore, or if so, only marginally so.
> OK.
> What will be the behavior of the predecessor of e.g. the csih function
> csih_create_unprivileged_user if called with USER without HOST prefix,
> machine is inside of domain and the user does not exist:
> - create local windows USER and require the config script to retrieve the
> actual Cygwin HOST+USER name,
> - fail and tell the calling config script to retry with HOST+USER instead
> (if possible),
> - create local windows USER and create a /etc/passwd entry to support a
> non-prefixed Cygwin USER in this case,
> - one of the above, selected by a new option.

I'm not exactly sure yet.  I'm working on it, and I ripped apart the
functions dealing with this problem by handling the cygwin username and
the windows username separately.  But it's not yet finished.  In theory
you have two cases.

Either the account already exists, then the user should (probably
(grain/salt)) specify the Cygwin username, which is either prefixed or
not prefixed, dependent on the DB it will get taken from.  The script
fetches the Windows domain and username from the U-... entry in pw_gecos

Or the account doesn't exist, then the username is just a name.  The
user account will be created in the local SAM and dependent on the state
of the machine, AD member or not, will be prefixed or not as Cygwin

Something like that.

> >>Local scripts from Cygwin users which use "mkpasswd -l" may need to be
> >>changed.
> >They are not supposed to use mkpasswd anymore since they don't need it,
> >only in very special circumstances.
> Wouldn't it be better to let mkpasswd -l simply fail with an explanatory
> error message instead of producing non-backward compatible results? Or at
> least print a warning to stderr?

But there still are cases in which using mkpasswd -l may be used.  If
somebody explicitely chooses to use "passwd: files"-only, then the
mkpasswd tool needs to generate accounts.

Is there any compromise possible which lets mkpasswd generate the
forward compatible accounts by default?  I made the change to mkpasswd
and mkgroup I outlined last week, but I deliberately didn't check it in
because I'm still hoping we find a compromise going forward.  I
understand that in your scenario you will have to use /etc/passwd for a
while longer.

But...  how many scripts would you really have to change if mkpasswd
generates prefixed names?  Alternatively, is setting some environment
variable feasible for tweaking the output of mkpasswd backward


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