Re: GSoC ShlibMemLoad

On Mon, Jul 7, 2008 at 5:28 AM, Andreas Kupries <akupries@...> wrote:

[...]

>> Because I have already studied this whole code for quite a long time
>> and have not came up with any solution I am thinking of writing an
>> email to John Polstra who is an author of the rtld for
>> FreeBSD. Maybe he will be able to help out. Do you think it is a
>> good idea?
>
> Yes. Getting the help of (one of) the original authors of some code is
> (in my opinion) a good idea. He should know the intricacies of the
> code.

As Daniel intends to contact John Polstra from FreeBSD I think that it
would be easier to work with him if Daniel installs FreeBSD and will
convey his experiments (and work with John) in this enviroment. I
would recommend installing FreeBSD on separate machine or in some kind
of virtual enviroment like VMware or VirtualBox to make simultaneous
testing easy (such a FreeBSD installation could run in runlevel 3
without graphical console to limit resources requirements).

>From high level perspective what we need is support in OS dynamic
linker to link with some libraries loaded by our program into memory
from some virtual filesystem specific to application (ex. starkit for
Tcl). Such feature can benefit not only Tcl, but also others who think
about single file deployments. As far as I understand MacOSX already
has got this functionality and other OS-es lack it. We currently try
to emulate it in Linux using code from FreeBSD. But maybe first we
should try to make it work in FreeBSD. FreeBSD folks can even maybe
add such capability as a system call (keep in mind that FreeBSD and
MacOSX shares some source code and maybe it could be also helpful).
Concerning Linux we decided to emulate loading dynlibs from memory
using FreeBSD code (due to licensing issues with GPL vs BSD). But
maybe we shall also contact Linux/glibc developers about including
proposed functionality in OS/glibc.

I don't know how we are going to handle Solaris and other platforms
that Tcl is known to run fine. It is certainly beyond scope of Daniels
Google Summer of Code project. But first we have to think also about
Microsoft Windows where starkit/starpack deployments will benefit
users the most. I have no idea how can we achieve it on Windows - I
don't think we can convince/help Microsoft to add such functionality
.

Regards,
Tomasz Kosiak

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