From: "piranna@gmail.com" <piranna@gmail.com>
To: musl@lists.openwall.com
Subject: Re: static build and dlopen
Date: Wed, 27 Aug 2014 22:19:18 +0200 [thread overview]
Message-ID: <CAKfGGh2A2zsSks_jknMDNy4kr2=jF+GbZwCWq8Hc8ceN46nZ6g@mail.gmail.com> (raw)
In-Reply-To: <53FE27E6.60902@skarnet.org>
>> Yes, I though about this option before, has a dumb statically linked
>> executable to work as PID 1 that just only exec Node.js and wait until
>> it finishes, so I can use a standard dynamically linked one and do
>> whatever I want
>
> I don't understand why you can't do whatever you want anyway.
> You can run Node.js as PID 1 even if it is dynamically linked - you
> just need to have the libc (and ld-musl.so) in the filesystem. It
> will work. You can run anything as PID 1 provided all its dependencies
> are there at boot time. Traditional inits are usually dynamically
> linked - which I think is a very bad idea, but that's another subject.
> If Node.js is a special case that cannot be treated that way, then I'm
> interested in hearing why.
I tried to do it that way, but didn't worked. Seems on Linux when you
are using a dynamically linked executable this is not run directly,
but instead it is exec internally /lib/ld-linux.so.2, that's a program
that load and link your executable and it's dynamic libraries and
later exec it, so it takes the PID 1 and when it finish and give
control to your dynamically linked executable (Node.js in this case),
then since PID 1 has exited, the kernel has a kernel panic. The same
happens if using /usr/bin/env as she-bang, since it will get the PID 1
and fail. You can read all that I have learned about this topics on
https://github.com/NodeOS/NodeOS-Docker/pull/12.
By the way, based on this example
(http://www.cs.utah.edu/dept/old/texinfo/glibc-manual-0.02/library_23.html#SEC410)
I've done a dumb /init program that just exec the dynamically linked
Node.js with the real /init in Javascript and it worked. Ugly hack,
but at least it does its job :-)
--
"Si quieres viajar alrededor del mundo y ser invitado a hablar en un
monton de sitios diferentes, simplemente escribe un sistema operativo
Unix."
– Linus Tordvals, creador del sistema operativo Linux
next prev parent reply other threads:[~2014-08-27 20:19 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-27 14:14 piranna
2014-08-27 15:27 ` Szabolcs Nagy
2014-08-27 17:01 ` piranna
2014-08-27 17:20 ` Justin Cormack
2014-08-27 20:07 ` piranna
2014-08-27 16:43 ` Rich Felker
2014-08-27 17:10 ` piranna
2014-08-27 18:48 ` Laurent Bercot
2014-08-27 20:19 ` piranna [this message]
2014-08-27 20:51 ` Rich Felker
2014-08-27 20:59 ` Laurent Bercot
2014-08-27 21:04 ` Rich Felker
2014-08-27 22:54 ` Kurt H Maier
2014-08-27 23:24 ` Laurent Bercot
2014-08-27 23:36 ` Brent Cook
2014-09-01 23:38 ` piranna
2014-09-02 0:38 ` Rich Felker
2014-09-02 0:49 ` piranna
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