[GRASSLIST:309] Re: after 2 days trying..

[Glynn Clements]

Guillaume Criloux wrote:

> > > I have changed the permission bits in root and still I
> > > cannot get a run.  
> > 
> > You have to own the mapset directory; having write permission isn't
> > sufficient.
> 
> Why is that?

I doubt that anyone who is currently associated with GRASS can answer
that. Presumably the original author had his reasons.

However, one possibility is that it's part of a rather bizarre locking
mechanims. GRASS won't allow a user to have more than one session; if
a mapset can only be modified by its owner, and its owner is limited
to a single session, there's no chance of two sessions concurrently
modifying a mapset.

> How can I setup a location/mapset to be able to share
> data between users without having them using the same login ?

Note that you can read data from any mapset (use g.mapsets to add
additional mapsets to the search path), but you can only write to the
current mapset (the one which was selected in the startup screen).

You could just change the behaviour of G__mapset_permissions() in
src/libes/gis/mapset_msc.c, but then you need to find some other way
to prevent multiple sessions from making concurrent modifications to a
mapset directory (possibly resulting in corrupton and/or loss of
data).

-- 
Glynn Clements <glynn.clements at virgin.net>