Re: Generic way to detect qemu linux-user emulation

[Helge Deller <deller@gmx.de>]

On 3/18/25 11:18, Andreas Schwab wrote:
> Is there a generic way for a program to detect that is it being run
> inside the linux-user emulation?

Yes, having a reliable way to detect it would be good.

My current (unreliable) way to detect it is using uname.
The kernel string and arch name don't match:

(sid_hppa)root@paq:/# uname -a
Linux paq 6.1.0-31-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.1.128-1 (2025-02-07) parisc GNU/Linux

(sid_hppa)root@paq:/# uname -r
6.1.0-31-amd64

(sid_hppa)root@paq:/# uname -m
parisc

This is a qemu-linux-user parisc(hppa) emulation running on x86-64.

> The purpose for that would be to work around limitations of the
> emulation, like CLONE_VFORK being unsupported.

yes, and robust futexes aren't supported either.

>  For example, python >=
> 3.13 needs to avoid using posix_spawn in that case, because the
> emulation of CLONE_VFORK as a true fork makes it impossible for it to
> report errors back to the parent process.