On Mon, Aug 26, 2024 at 10:57:12AM +0200, Stefano Brivio wrote: > On Mon, 26 Aug 2024 18:47:27 +1000 > David Gibson wrote: > > > On Mon, Aug 26, 2024 at 10:37:23AM +0200, Stefano Brivio wrote: > > > On Mon, 26 Aug 2024 18:20:35 +1000 > > > David Gibson wrote: > > > > > > > On Mon, Aug 26, 2024 at 09:55:47AM +0200, Stefano Brivio wrote: > > > > > On Mon, 26 Aug 2024 16:39:01 +1000 > > > > > David Gibson wrote: > > > > > > > > > > > The statement in the comment about /usr/libexec being only for running on > > > > > > other hosts simply isn't true, neither in practice nor according to the > > > > > > FHS spec[0]. > > > > > > > > > > I don't remember where I took that meaning of /usr/libexec from, I > > > > > guess it's from some outdated packaging guidelines (Fedora? Kata > > > > > Containers?). Sure, it makes sense to fix that. > > > > > > > > > > > Furthermore this logic didn't even handle it correctly, since > > > > > > it would only handle binaries _directly_ in /usr/libexec, not those in > > > > > > (explicitly FHS permitted) subdirectories under /usr/libexec. > > > > > > > > > > So, this change breaks the two cases I needed to cover with this, which > > > > > are /usr/libexec/kata-agent in general, and /usr/libexec/qemu-kvm on > > > > > RHEL 9. > > > > > > > > Huh.. why? > > > > > > Because they're not in PATH on the guest, so we can't execute them. > > > > But.. they wouldn't have been in the PATH on the host either, so > > whatever front end binary is using them must have found them by some > > other means. > > If you actually use the front-end binary, sure. The issue is the > interpretation of "intended" in the FHS description: > > /usr/libexec includes internal binaries that are not intended to be > executed directly by users or shell scripts. > > ...not intended on a specific distribution? Or due to their nature? Right. I mean, it's kind of necessarily the former, since the distro makes the decision. And that category will include things in the latter as well. > > > As an alternative, we can unconditionally add /usr/libexec to it using > > > $FIXUP. I added the lines moving stuff to /usr/bin before I implemented > > > the $FIXUP mechanism, and I needed to run kata-agent as init. > > > > > > But now that $FIXUP is available, that's probably less invasive. > > > > > > > > What does it fix? > > > > > > > > I don't have a concrete case, but it would break anything where we're > > > > including this support binary, but the "front end" binary looks for it > > > > explicitly in /usr/libexec. Which I'd kind of expect to be most > > > > support binary cases, since by design /usr/libexec won't generally be > > > > in the PATH. > > > > > > I see. Well, given the limited time I can spend on maintaining mbuto, > > > I'd really prefer to just fix concrete issues, but this looks obvious > > > enough -- as long as we have another way to keep qemu-kvm usable in the > > > guest. > > > > Ah... I guess for qemu-kvm we're intentionally taking what's a support > > binary on the host and using it as a primary binary on the guest. > > Right, same for kata-agent. > > > That's different from the sshd-session case, where it's a support > > binary in both environments. > > > > I'd favour leaving the path of the binary itself alone and explicitly > > adding a link from /usr/bin for the qemu-kvm case. > > We could add a link from /usr/bin for all the paths we find in > /usr/libexec, then, to keep it more general. But is it really worth the > effort compared to just adding /usr/libexec to $PATH on the guest? Fair point, it's not like the mbuto minimal environment needs to be strictly FHS-ishly correct. -- David Gibson (he or they) | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you, not the other way | around. http://www.ozlabs.org/~dgibson