Re: static build and dlopen

[Justin Cormack <justin@specialbusservice.com>]

On Wed, Aug 27, 2014 at 6:01 PM, piranna@gmail.com <piranna@gmail.com> wrote:
> The de-facto standard in Node.js is that all the compiled modules are
> static ones (.a files) with no external dependencies at all, just to
> make it simpler to move to another environments. This contrast to how
> Python works, where compiled modules are dynamic ones (.so). I'm
> honestly not sure what are the low-level details of Node.js compiled
> modules, but the general idea of Node.js modules is make them as
> independent as possible and left to Node.js require() function to
> manage the dependencies, so probably this would also apply to compiled
> ones... Only point left here is if in fact .node files are in fact .a
> files with a different extension or if they are wrapped someway, so in
> that case dlopen() is efectively loading .a files (that would be a
> surprise to me, but would left open the door to solve this problem...)

If this is really true, and they are static, then you should be able
to write a loader that has a function called dlopen etc but which is
not actually the full dynamic linker, just pretends to be, and will
work from a static binary. It could link in the modules at compile
time and just return static pointers (I have done this with Lua code,
pretending to be in a dynamic environment when actually in a static
one, just return pointers from dlsym calls that are fixed at compile
time).

Justin