On Saturday 03 February 2001 17:36, [EMAIL PROTECTED] wrote:
[...]
> As someone already asked - is anyone using shared memory on whole
> functional objects, as opposed to just data structures?

The closest I've been is considering it as a way of running audio plugins 
under an RTL host.


> Is there any
> reason this wouldn't be possible, assuming all code adheres to the
> header/library standards associated with both environments?

The problem is relocation. Normal object files are relocated when loaded, and 
won't run if placed at a different address, so you have to make sure that the 
code is mapped to the same address range as is was loaded into. If that's 
handled properly it should work, i think...

Another problem is importing/exporting symbols. The shared code would have to 
rely entirely on arguments passed to it's functions, as it cannot import any 
symbols from user space or kernel space when loaded.

It *could* possibly link at runtime, but then one would have to make sure 
that the data storage is mapped into different physical places if the code is 
to be shared between user and kernel space!


> I'm not
> sure why this would be useful, but it sounds cool.

The strongest motivation for me would be to be able to run plugins not 
explicitly written for kernel space. However, as the kernel module loader 
seems to be essentially a stripped down object file loader, the easiest way 
would be to just load the plugins as kernel modules instead of shared 
libraries - MAIA plugins will probably export nothing and import a few host 
calls, so as long as the kernel module loader can load anything that can be 
resolved, even without init/cleanup functions, this should work without 
special hacks.

Either way, as soons as code is executed in kernel space, security is but an 
illusion, and "shared code" wouldn't be any different, except that it can't 
easilly import kernel symbols. (Having to run an engine process as root is 
serious enough for applications meant to run on workstations...)


//David

.- M A I A -------------------------------------------------.
|      Multimedia Application Integration Architecture      |
| A Free/Open Source Plugin API for Professional Multimedia |
`----------------------> http://www.linuxaudiodev.com/maia -'
.- David Olofson -------------------------------------------.
| Audio Hacker - Open Source Advocate - Singer - Songwriter |
`--------------------------------------> [EMAIL PROTECTED] -'
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