Re: [Plash] executable objects and cwd

[Toby Murray]

Mark Seaborn wrote:

> exec-object doesn't implement setting the cwd.
>
> I have just fixed this in SVN.
>
>  
Cool, thanks.

> Suppose your cwd is "/home/fred":
>
>  
>
> > if I run
> >
> > my_getcwd /somedir
> >
> > (where /somedir is the path to the 'getcwd' binary)
> > instead it says "leaving cwd unset".
> >    
>
> Here the namespace created by the shell for this command only contains
> "/somedir".  The namespace doesn't contain "/home/fred" so the cwd is
> not set.  The shell doesn't add in defaults like "/usr", "/bin"
> etc. when invoking executable objects.  exec-object later unions this
> namespace with another namespace that contains "/somedir", but the
> shell doesn't know about that.
>  
I think I see what you mean. I might create an executable object with 
its initial namespace containing  "/home/fred". I might then invoke it 
passing a namespace with "/somedir". (Its eventual namespace will 
contain both "/home/fred" and "/somedir", right?) If my cwd is 
/home/fred, the shell can't determine that this will in-fact end up 
being  in the executable object's namespace since it only knows about 
the namespace being passed with the invocation.

Is there a problem with the shell sending the cwd as an argument 
regardless of whether it thinks it will be in the executable object's 
namespace? It would be up to the object to determine whether the 
argument passed by the shell was actually in its namespace and if so, 
then set its cwd.

The other solution would be to add a method to query the executable 
object about its initial namespace. That would allow the shell to 
properly determine whether it should pass the cwd argument.

--
Toby Murray
Advanced Computer Capabilities Group
Information Networks Division
DSTO, Australia

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