Re: [PATCH proxmox-backup v3 14/15] tape: use proxmox-product-config to generate create options

[Robert Obkircher <r.obkircher@proxmox.com>]

On 20.07.26 16:12, Christian Ebner wrote:
> On 7/6/26 2:28 PM, Robert Obkircher wrote:
>>
>> On 01.07.26 16:05, Christian Ebner wrote:
>>> Instead of redefining them, use the global helper defined in
>>> proxmox-product-config. Requires the crates init function to be
>>> called exactly once before using in any callpath.
>>>
>>> Signed-off-by: Christian Ebner <c.ebner@proxmox.com>
>>> ---
>>>   src/tape/inventory.rs           |  6 +-----
>>>   src/tape/media_catalog_cache.rs | 10 +---------
>>>   2 files changed, 2 insertions(+), 14 deletions(-)
>>>
>>> diff --git a/src/tape/inventory.rs b/src/tape/inventory.rs
>>> index 6c54738fb..12cca02c6 100644
>>> --- a/src/tape/inventory.rs
>>> +++ b/src/tape/inventory.rs
>>> @@ -177,11 +177,7 @@ impl Inventory {
>>>               // We cannot use chown inside test environment (no
>>> permissions)
>>>               CreateOptions::new().perm(mode)
>>>           } else {
>>> -            let backup_user = pbs_config::backup_user()?;
>>> -            CreateOptions::new()
>>> -                .perm(mode)
>>> -                .owner(backup_user.uid)
>>> -                .group(backup_user.gid)
>>> +            proxmox_product_config::default_create_options()
>>>           };
>> I think the then branch of this if statement could be removed, because
>> for cfg!(test) the backup_user is already set to the current user.
>
> Thanks for the hint, at first glance it should behave as you
> expected but I can trigger test failures without that, getting an
> EPERM error on fchown on CreateOptions::apply_at(). I guess this is
> caused by (man 2 fchown):
>
> > Only a privileged process (Linux: one with the CAP_CHOWN
> capability) may change the owner of a file.
>
> Didn't investigate further though and opted for leaving the checks
> in place. 


Chown does work if the user stays the same and is a member of the
target group:

robkircher@devel:~$ strace --trace=fchownat chown
robkircher:robkircher test
fchownat(AT_FDCWD, "test", 1000, 1000, 0) = 0

It looks like the real problem is that pbs_config is a separate crate,
so cfg(test) is always false there.