[pacman-dev] Non-existing user/group ownership and chroot

[Armin K.]

On 06.03.2017 17:48, Andrew Gregory wrote:
> On 03/06/17 at 05:40pm, Armin K. wrote:
>> On 06.03.2017 14:45, Andrew Gregory wrote:
>>> On 03/06/17 at 10:12am, Armin K. wrote:
>>>> On 06.03.2017 00:17, Armin K. wrote:
>>>>> On 06.03.2017 00:10, Allan McRae wrote:
>>>>>> On 06/03/17 09:04, Armin K. wrote:
>>>>>>> On 06.03.2017 00:00, Allan McRae wrote:
>>>>>>> Entries are alright in .MTREE (correct gid's). I don't suppose pacman
>>>>>>> does something odd there? Why doesn't it use those uid's/gid's?
>>>>>>>
>>>>>>> If you could point me to the part in the pacman code which does the
>>>>>>> extraction, I might be able to find a solution (at least for myself).
>>>>>>>
>>>>>>
>>>>>> Extraction is just taking files out of the tarball.  Note that the
>>>>>> tarball store files with UID/GID numbers and not names.
>>>>>>
>>>>>> A
>>>>>>
>>>>>
>>>>> Oh my. Something else is at play here. Manually extracted tarball
>>>>> contains wrong permissions, .MTREE file reports correct permissions.
>>>>>
>>>>> pkg/ directory is sadly only owned by the build user. I suppose
>>>>> something between package() and the tarball creation (or just
>>>>> the tarball creation) screws things up. Any ideas what it might be?
>>>>>
>>>>> libarchive version is 3.3.0.
>>>>> fakeroot is 1.20.1.
>>>>
>>>> This is indeed libarchive/bsdtar problem. The permissions are just fine
>>>> when extracted in chroot, but not when extracted from outside of it.
>>>>
>>>> Looks like behaviour changed, and that tarball stores uid/gid isn't
>>>> true (anymore). Directory owned by a certain user is owned by the
>>>> same user in and outside of chroot, besides two of them having different
>>>> uids/gids.
>>>
>>> This sounds like the expected behavior.  The user/group names are
>>> stored in the archive if they exist on the system building the package
>>> and bsdtar will use the names rather than the id's by default when
>>> extracting the archive.
>>>
>>> apg
>>>
>>
>> I've contacted libarchive devs and they suggested --numeric-owner bsdtar
>> option. It works just as I expect it to.
> 
> pacman already only uses the numeric id's during extraction.
> 

It might be libarchive bug/feature. I've found archive_write_disk_set_standard_lookup()
which will force resolving uid/gid's if used. The trick is, version 3.3.0 I compiled
packman against, calls such function almost uncoditionally in archive_read_extract().

https://github.com/libarchive/libarchive/blob/master/libarchive/archive_read_extract.c#L49