Re: [PATCH] test: fix 'make assets' failure as root

On Thu, 25 Sep 2025 11:27:49 +0100 "Richard W.M. Jones" wrote:

On Thu, Sep 25, 2025 at 11:40:25AM +0200, Stefano Brivio wrote:

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On Thu, 25 Sep 2025 09:53:06 +0100 "Richard W.M. Jones" wrote:

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On Thu, Sep 25, 2025 at 01:43:06PM +0800, Yumei Huang wrote:

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Running `make assets` under `test` as root fails with a "Permission denied" error when `prepare-distro-img.sh` invokes `virt-edit` and `guestfish`. This is due to a known bug in libvirt.

Work around the issue by switching to the direct backend.

Signed-off-by: Yumei Huang --- test/prepare-distro-img.sh | 2 ++ 1 file changed, 2 insertions(+)

diff --git a/test/prepare-distro-img.sh b/test/prepare-distro-img.sh index 0d967c9..423eea7 100755 --- a/test/prepare-distro-img.sh +++ b/test/prepare-distro-img.sh @@ -3,6 +3,8 @@ IMG="$1" PASST_FILES="$(echo ../*.c ../*.h ../*.sh ../*.1 ../Makefile ../README.md)"

+export LIBGUESTFS_BACKEND=direct

Please add a comment that this is only added as a temporary hack until we can get a proper fix (in libguestfs possibly, see Dan's earlier email).

On the other hand, regardless of that fix, I would be happy to be run this on single-user Alpine L1 guests, eventually, where libguestfs doesn't depend on libvirt (see my caveat 2.), and I usually reserve very little disk space for those.

The upstream default is backend 'direct'. In Fedora & RHEL we override this with 'libvirt':

https://src.fedoraproject.org/rpms/libguestfs/blob/rawhide/f/libguestfs.spec...

Ah, sorry, I had no idea!

I don't know what Alpine does, but likely it leaves it at the default. (You can try: `guestfish get-backend`)

Yes, this is guestfs-tools and libguestfs 1.56.1-r0 on Alpine: # guestfish get-backend direct Same on any modern Debian, openSUSE, Ubuntu.

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If you don't have compelling reasons (like you're dropping LIBGUESTFS_BACKEND=direct in two weeks), I would simply keep this as long as it works. The day you drop that, we'll drop this too.

We're not dropping the environment variable / feature ever. The problem is that this was cargo-culted into a lot of code over the years, and it does reduce the security of libguestfs on RHEL. We're having an (ongoing) battle to remove this cargo-culting from CNV right now. I'm just not keen to add this line in new places, without at least a comment saying this is a temporary hack, and not generally recommended.

Oh, I see, that makes sense. But then, Yumei, we should also add to that comment (sorry, this is becoming much more complicated than I thought...) that the workaround is for Fedora and related distributions. -- Stefao