Re: [PATCH v8 0/7] Add pidfd and cgroupv2 support for process creation

[Florian Weimer <fweimer@redhat.com>]

* Rich Felker:

> On Mon, Aug 21, 2023 at 08:53:53AM +0200, Florian Weimer wrote:
>> I think clone3 with exit_signal set to 0 and CLONE_PIDFD allows the
>> creation of subprocesses that are difficult to observe by accident from
>> the rest of the process, while obtaining a stable identifier for the
>> process.  I do not think there is any other way to achieve that.  I
>> think it's desirable to expose this functionality in some way.
>
> Indeed that seems like useful functionality to expose for cases where
> you can't fix some bad code, but there are lots of issues with how

It's more about providing a confirming implementation of function in the
wait family in case the implementation needs to create processes for
some reason.  It's not about “bad code”, these are standard POSIX
interfaces.

> clone3 (and even clone) should behave with respect to the child
> environment when you don't exec -- is it _Fork-like or fork-like? Can
> you use AS-unsafe interfaces in the child of a MT parent? Etc. This
> should all be discussed on libc-coord not libc-alpha, IMO.

Seems more like linux-api material, given that it's Linux-specific?

Thanks,
Florian