[CRIU] Changing process environ, euid

[Christopher Covington]

Hi Rektide,

On 01/07/2015 10:54 PM, rektide at voodoowarez.com wrote:
> Hello,
> 
> What means does CRIU use to set up a process environ? I'm hoping there is some wisdom this particular
> instrumentation group can lend, and I'm hoping there's some really bad nasty awful means to manipulate environ
> of a running process. I'm also curious about how euid is setup, and whether there's any available ways to
> instrument a process euid in linux?

I don't know if this will help in your specific situation, but here's a
writeup on user namspaces:

https://lwn.net/Articles/532593/

A tool called CRIT to view and manipulate checkpoint images is under development.

http://criu.org/CRIT

`criu exec` allows you to execute a single system call as another process.

> Longstanding dream of mine:
> I think it'd be awesome to take a complex program many users on a system run, and to be able to have a launcher
> that takes that STOP'ed program, clones an instance (I could do this via some signalling between launcher and
> the program forking itself, having forked copies be the thing the launcher manipulates for users), and has the
> clone (here a forked child intended to be the user's) tweaked.

This makes me think of Zygote on Android, which I've read has common libraries
pre-loaded that each forked child inherits.

http://anatomyofandroid.com/2013/10/15/zygote/

Chris

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