setup/mkpasswd and HOMEDRIVE/HOMEPATH

[Larry Hall (Cygwin Developers)]

Corinna Vinschen wrote:
> On May  7 00:44, Larry Hall (Cygwin Developers) wrote:
>> Dave Korn wrote:
>>> Larry Hall (Cygwin Developers) wrote:
>>>> I was basically thinking of the pathelogical case where the user
>>>> doesn't have permissions to create or access the home directory
>>>> due to some strange phenomena (somebody messed up permissions,
>>>> '/home/<user>' points to a shared drive that's inaccessible, etc.).
>>>   I was thinking of that too, but I'd hardly call it 'pathological'.  It's
>>> standard practice on Linux for /home to be owned by root and only have r-x
>>> perms for everyone else, as root is the only one who should be adding new
>>> users and hence the only person who should be creating dirs in /home.
>>>
>>>   In cygwin we're effectively letting non-admin users control most of the
>>> 'adduser' behaviour themselves.  Someone might easily think that chmod'ing
>>> /home 755 was a good idea.
>> Right.
>>
>> And as to the terminology, let's call them "corner cases" instead so no one
>> gets hung up on semantics. :-)
> 
> But how's that supposed to work?  Right now (and also in the former
> code) Cygwin doesn't (and didn't) check for any directory permissions.
> Evaluating the home directory is just a question of where to get the
> information from

<a very useful/helpful description of new/old setup behavior relative
  to the home directory snipped for brevity>

> Back to the / fallback.
> 
> Right now, what happens is this:
> 
> If /home/$USER exists, but cd to it fails due to missing permissions,
> the shell will end up in the former current directory.  This is typically
> /bin or /usr/bin.

Right.

> If /home/$USER does not exist, the /etc/profile mechanism kicks in.
> If /home does not have sufficient permissions for the user to create
> his/her own home dir, something like this will happen:
> 
>   mkdir: cannot create directory `/home/corinna': Permission denied
>   /home/corinna could not be created.
>   Setting HOME to /cygdrive/c/Users/corinna/AppData/Local/Temp.
> 
> When not using bash, but tcsh, the following happens:
> 
>   mkdir: cannot create directory `/home/corinna': Permission denied
>   cd: Can't change to home directory.
>   [/usr/bin]$
> 
> I don't see anything wrong with this behaviour.  Maybe /etc/profile
> should choose / rather than $TEMP as fallback HOME dir?  And maybe tcsh
> should align its behaviour and set HOME to / as well if mkdir fails to
> work?

I agree there's nothing wrong with the behavior in the cases you described
above.  It might be a "good thing"(tm) to have the "don't know/can't
access" case always use /.  I wouldn't say that it's worth doing
back-flips to achieve though.  It may not even be worth mild effort. ;-)

> What other pathological case am I missing?

Actually, I think this covers the general category of home directory
inaccessibility behavior.  Dave, anything else you see?

-- 
Larry Hall                              http://www.rfk.com
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