Re: [PATCH 1/2] test/perf: Check for /sbin/sysctl with which(1), not simply sysctl

[Stefano Brivio <sbrivio@redhat.com>]

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On Sat, 17 Sep 2022 13:27:32 +1000
David Gibson <david(a)gibson.dropbear.id.au> wrote:

> On Sat, Sep 17, 2022 at 01:55:33AM +0200, Stefano Brivio wrote:
> > Otherwise, we're depending on having /sbin in $PATH. For some reason  
> 
> Huh.  I wonder why this is working for me.

Different shells, or different shell profiles, I guess?

> > I didn't completely grasp, with the new command dispatch mechanism
> > that's not the case anymore, even if I have /sbin in $PATH in the
> > parent shell.  
> 
> For the guest, there's no mystery - there's no strong connection
> between the shell environments there.  We probably can control PATH
> with our mbuto setup though.
> 
> For the ns that is strange, though.

I think the reason is that with:

        echo "nsenter $@ sh -c" > "${__enter}"

you get a different behaviour than nsenter with an interactive shell
(previous implementation). For example, on Debian, commands (by default)
will run with dash instead of bash.

In any case, just using 'which sysctl' looks wrong to me, and that can
break for many other reasons, so I don't feel very inclined in digging
into the actual reason and differences between environments here.

-- 
Stefano