[OE-core] [RFC PATCH 0/3] Shared state for all !

[Khem Raj]

On Wed, May 9, 2012 at 8:14 PM, Joshua Lock <josh at linux.intel.com> wrote:
> On 09/05/12 20:10, Joshua Lock wrote:
>>
>> On 09/05/12 19:32, Joshua Lock wrote:
>>>
>>> On 09/05/12 19:15, Chris Larson wrote:
>>>>
>>>> On Wed, May 9, 2012 at 6:05 PM, Joshua Lock<josh at linux.intel.com> wrote:
>>>>>
>>>>>
>>>>>
>>>>> On 09/05/12 17:50, Chris Larson wrote:
>>>>>>
>>>>>>
>>>>>> On Wed, May 9, 2012 at 5:22 PM, Joshua Lock<josh at linux.intel.com>
>>>>>> wrote:
>>>>>>>
>>>>>>>
>>>>>>> In Yocto #2041[2] Mark reported an issue with reusing shared state
>>>>>>> as a
>>>>>>> different user on the same machine.
>>>>>>>
>>>>>>> Since the whole purpose of shared state is that it be shared I
>>>>>>> decided to
>>>>>>> dig
>>>>>>> into this issue. I wanted to at least be able to use the shared-state
>>>>>>> cache of
>>>>>>> a different user without error, even if all of the objects aren't
>>>>>>> actually used
>>>>>>> (i.e. native, at least on the Edison branch I did most of the testing
>>>>>>> with).
>>>>>>>
>>>>>>> This is an RFC mainly because it changes the permissions of created
>>>>>>> directories,
>>>>>>> sstate files and siginfo files from what they have traditionally
>>>>>>> been.
>>>>>>>
>>>>>>> There is more of the rhyme an reason in the patch commit headers and
>>>>>>> comments
>>>>>>> but tl;dr bb.mkdirhier directories will be 0777 (rwxrwxrwx) with this
>>>>>>> patch, as
>>>>>>> will all of the contents of sstate-cache (siginfo and tgz) files.
>>>>>>>
>>>>>>> This is actually what one would expect from reading the Python API
>>>>>>> docs
>>>>>>> for
>>>>>>> os.makedirs "The default mode is 0777 (octal)."[1] but not what
>>>>>>> actually
>>>>>>> happens
>>>>>>> on most modern Linux systems thanks to umask.
>>>>>>>
>>>>>>> Please review the following changes for suitability for inclusion.
>>>>>>> If you
>>>>>>> have
>>>>>>> any objections or suggestions for improvement, please respond to the
>>>>>>> patches. If
>>>>>>> you agree with the changes, please provide your Acked-by.
>>>>>>
>>>>>>
>>>>>>
>>>>>> 777 seems questionable to me, personally. Generally collaboration
>>>>>> happens amongst folks within a group, and chmod g+s makes that easier.
>>>>>> I'd expect 775 to be a more sane value, myself.
>>>>>
>>>>>
>>>>>
>>>>> Do you mean for bb.mkdirhier calls, the tgz files, the siginfo files or
>>>>> everything?
>>>>>
>>>>> I went with 777 for mkdirhier as that's the default of os.makedirs
>>>>> before
>>>>> umask is involved. I would likely have picked rw-rw-r-- (664) if I
>>>>> weren't
>>>>> trying to request comments.
>>>>
>>>>
>>>> Gotcha.
>>>>
>>>> I'm concerned about the behavior change and potential implications of
>>>> changing the default behavior of mkdirhier. I'm inclined to say that
>>>> when you don't pass mode, let it use the current behavior of obeying
>>>> the umask.
>>>
>>>
>>> An earlier version of the series did this and I'm happy to add that
>>> behaviour back in.
>>>
>>> If we're not going to do that, and want to change the
>>>>
>>>> default behavior, then I think 777 is the wrong/questionable default.
>>>> Beyond that, 777 is certainly the wrong mode to be using for the
>>>> shared state package in sstate.bbclass.
>>>
>>>
>>> Do you have a strong preference on 664 vs. 775 ?
>>
>>
>> I'm leaning towards 664 (rw-rw-r--) for the files and 775 (rwxrwxr-x)
>> for directories, these are the defaults for file and directory creation
>> on Ubuntu 12.04 and Fedora 16.
>
>
> At which point, the obvious "solution" to the bug report is a sanity check
> whether the user can read and write to the sstate directory.

may be its already taken care of but I will ask anyway, if shared
state is writable for all
how is contention resolved when someone tries to update the shared
state since he/she rebuilt the package for some reason. I think having
a global shared cache to read from but not update it would be
something interesting where shared state is updated by say an
autobuilder and used by developers in their local builds.

On perm issue  could it be made that if the file is readable by user
then while unpacking it gets the umask of current user ?

-Khem