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Re: On PATH_MAX
From: |
Jonathan S. Shapiro |
Subject: |
Re: On PATH_MAX |
Date: |
Tue, 08 Nov 2005 11:58:48 -0500 |
On Tue, 2005-11-08 at 17:34 +0100, Bas Wijnen wrote:
> On Tue, Nov 08, 2005 at 08:51:09AM -0700, Christopher Nelson wrote:
> > > Not exactly. If a server wants to support arbitrary long
> > > paths, it's not going to map the whole thing into its address
> > > space. It'll accept a container capability and map parts of
> > > it in, unmapping other parts of it.
> >
> > What mechanism allows it to map *parts* of a single transfer in?
>
> There is no transfer of data, there is only transfer of the container
> capability. This capability gives access to a set of pages, which can be
> mapped in or out of the address space when the process likes.
Operationally this is correct, but the mechanism described is
unfortunate if your description is intended literally.
If I hold a capability to a memory object, what I have is the authority
to map a *window* on each page within that object, subject to the
permission restrictions of the memory object.
The difference between mapping such a window and mapping the page
directly is that the window becomes invalid if the memory object is
destroyed.
The distinction is subtle, but important.
shap
- Re: On PATH_MAX, (continued)
- RE: On PATH_MAX, Christopher Nelson, 2005/11/08
RE: On PATH_MAX, Christopher Nelson, 2005/11/08