Re: [PATCH 1/6] tools/nolibc: add support for waitid()

Willy Tarreau
2024-12-21T16:36:08Z

Hi Thomas!

On Sat, Dec 21, 2024 at 03:44:28PM +0100, Thomas Weißschuh wrote:
> waitid() is the modern variant of the family of wait-like syscalls.
> Some architectures have dropped support for wait(), wait4() and waitpid()
> but all of them support waitid().
> It is more flexible and easier to use than the older ones.

I'm generally fine with the series, but I'm starting to get concerned
that some simple applications that used to rely on wait() or waitpid()
will not work on this architecture. Just like we did for some early
syscalls that got replaced (e.g. open->openat etc), I think we'll have
to implement a default wrapper relying on waitid() for all these calls
in this case, and maybe as well for lseek->llseek() btw, what do you
think ?

The single fact that you've had to modify some of the nolibc-test code
(which is supposed to be the application here) indicates that we're
progressively going away from what applications need on certain archs.
Ideally an application relying on long-established calls should continue
to work unmodified.

Maybe it will be time for us to run an overall audit of arch-dependent
syscalls we currently have, to make sure that the common ones continue
to work fine there (and waitpid() definitely is as common a syscall as
open() since it's the good old and portable one).

Cheers,
Willy