[CRIU] External network namespaces

[Adrian Reber]

On Thu, Sep 13, 2018 at 11:33:17AM +0200, Adrian Reber wrote:
> when we initially talked about external network namespace and how RPC
> can get those FDs you mentioned FD clashes.
> 
> I am now hitting such a FD clash:
> 
> (00.197735)      1: Inherit fd extRootNetNS -> 4 has been reused
> (00.197738)      1: Error (criu/util.c:251): fd 4 already in use (called at criu/files.c:1102)
> (00.197743)      1: Error (criu/files.c:1205): Unable to open fd=4 id=0x7d
> 
> I understand it in such a way that CRIU gets the network namespace via
> FD 4, but the restored process also uses FD 4 and cannot use the
> information from inherit FD. Any idea how to solve this? Thanks.

So if I just 'dup2(4, 99);' then it works. What is the right way in CRIU
to move an FD out of the way. There are so many FD related functions and
I am not sure which one is the right for this use case.

		Adrian