Re: Shared Memory
Mon, 12 May 1997 00:03:53 -0400 (EDT)

> >
> > Does anyone know of a systtem call that is available so that given a
> > process ID and a physical range of pages, one process could map that
> > physical memory into the address space of the process that corresponds to
> > the given PID?
> If you use the mmap() call on /dev/mem you can do this, it's a well
> known hack for accessing hardware from user-space.

The only catch with this is that it does not allow me to map into
ANOTHER process' address space, only my own. The problem I am trying to
address is that I have one process running as root and another process
that is not. The non-root process communicates with the root process and
asks it for locked-in pages. The root process will then map the locked
pages it has in its address space into the client's address space and
return a pointer to this area back to the client. As far as I know mmap
only operates on one's own address space. If I could somehow modify it
so it worked on another process' address space, that would rock.