[Devel] Re: [PATCH v7 09/10] IPC: message queue copy feature introduced

[Michael Kerrisk (man-pages)]

>> Is there somewhere a *detailed* description of how this feature would
>> be used? Lacking that, it's really hard to see how anything sane and
>> reliable can be done with MSG_COPY.
>>
>
> These patches are used by CRIU already.
> So, you can have a look at the CRIU source code:
>
> http://git.criu.org/?p=crtools.git;a=blob;f=ipc_ns.c;h=9e259fefcfc04ec0556bb722921545552e1c69f3;hb=HEAD
>
> Sanity and reliability on the level you are talking about can be achieved,
> only if you'll freeze all message users before peeking.

Okay -- that's the piece I was looking for. Thanks.

In this scenario, how do you find all of the message users? Or do you
simply ensure that everything is frozen beforehand?