enforce_statfs showing leading path

[Bjoern A. Zeeb]

On 9 Jan 2019, at 9:42, Alexander Leidinger via freebsd-jail wrote:

Hi,

I’ll be a bit verbose also for mwlucas.

> You see the dataset name of zfs without stripping. The mount point is 
> correctly stripped. I don't remember how this looks on ufs.

/dev/ada0p19 on / (ufs, local, journaled soft-updates)
/local/data/www1/users/johndoe on /usr/home/johndoe/www1 (nullfs, local)

The “device” is also visible there, as well as file system type and 
specific options.

I also added a nullfs example.  For that the mount point is properly 
treated and lost the /local/jails/whatever/ prefix with enforce_statfs=1 
but the “device” side is just as visible in full as it is for a any 
other real device.


> With jailed datasets we would need more than just some code to remove 
> parts of the name.
>
> So it's a doc bug (clarity about mount points and dataset names) and a 
> zfs issue.

Well, no it’s not a zfs specific issue.  And the docs talk about mount 
points not about the “device” (or dataset in zfs parlance).

If anything for clarity one could add a sentence to the jail(8) page 
saying that the “device” part of the mount output is not being 
restricted or altered.


One of the reasons for enforce_statfs certainly was to limit the amount 
of information;  that also has the side-effect of scripts parsing the 
mount (mount points) output actually finding the paths they might be 
looking for.


The df command output might make some of this all a bit more clear.



> Am 8. Januar 2019 8:34:17 nachm. schrieb "Michael W. Lucas" 
> <mwlucas at michaelwlucas.com>:
>
>> Hi,
>>
>> I'm experimenting with enforce_statfs for the jails book, and have 
>> hit
>> an inconsistency. Not sure if the bug should go to src or doc. 
>> Running
>> last week's -current.
>>
>> According to jail(8):
>>
>> When set to 1, only mount points below the jail's chroot
>>             directory are visible.  In addition to that, the path to 
>> the
>>             jail's chroot directory is removed from the front of 
>> their path‐
>>             names.
>>
>> Seems pretty clear that I shouldn't see anything other than
>>
>> # jls -h name enforce_statfs
>> ...
>> ioc-www1 1
>>
>> So, as I read it, the jail's chroot directory should be stripped down
>> to /. But inside the jail:
>>
>> root at www1:~ # mount
>> iocage/iocage/jails/www1/root on / (zfs, local, nfsv4acls)

                                   ^^^^ it is stripped down to /

>> devfs on /dev (devfs, local, multilabel)
>> fdescfs on /dev/fd (fdescfs)
>>
>> I see the jail's chroot directory.
>>
>> This seems to contradict the man page, unless I'm misunderstanding.
>>
>> Is this a software bug? A ZFS thing? A doc bug? Or am I just an 
>> idiot?
>>
>> Also, should this path be stripped when enforce_statfs is set to 1 
>> *or
>> above*? Or is this strictly when set to 1? If I'm filing a bug, it
>> might as well be complete...
>>
>> Thanks,
>> ==ml
>>
>> --
>> Michael W. Lucas https://mwl.io/
>> author of: Absolute OpenBSD, SSH Mastery, git commit murder,
>> Immortal Clay, PGP & GPG, Absolute FreeBSD, etc, etc, etc...
>>
>>
>>
>> ----------
>> _______________________________________________
>> freebsd-jail at freebsd.org mailing list
>> https://lists.freebsd.org/mailman/listinfo/freebsd-jail
>> To unsubscribe, send any mail to 
>> "freebsd-jail-unsubscribe at freebsd.org"
>
>
>
> _______________________________________________
> freebsd-jail at freebsd.org mailing list
> https://lists.freebsd.org/mailman/listinfo/freebsd-jail
> To unsubscribe, send any mail to 
> "freebsd-jail-unsubscribe at freebsd.org"