[Buildroot] trying to add python-smbus-cffi, but installing fails

[Yegor Yefremov]

On Fri, Mar 13, 2015 at 6:22 PM, Yegor Yefremov
<yegorslists at googlemail.com> wrote:
> On Fri, Mar 13, 2015 at 6:08 PM, ir. Tjeerd Pinkert <t.j.pinkert at vu.nl> wrote:
>> Hi,
>>
>> I was trying to install the python smbus-cffi as a package (currently in my
>> BR2_EXTERNAL directory) but installation fails.
>>
>> It looks like the package is trying to load itself to register, but of
>> course it fails because I think the host python loads this, and can not load
>> the _cffi_backend.so compiled for the target?
>>
>> Anyone an idea how to get solve this chicken egg problem?
>>
>> This is the part where the install script fails:
>> Installed
>> /local/opt/freescale/buildroot/output/build/python-smbus-cffi-0.4.1/pycparser-2.10-py2.7.egg
>> Traceback (most recent call last):
>>   File "setup.py", line 7, in <module>
>>     import smbus
>>   File
>> "/local/opt/freescale/buildroot/output/build/python-smbus-cffi-0.4.1/smbus/__init__.py",
>> line 1, in <module>
>>     from .smbus import ffi
>>   File
>> "/local/opt/freescale/buildroot/output/build/python-smbus-cffi-0.4.1/smbus/smbus.py",
>> line 40, in <module>
>>     ffi = FFI()
>>   File
>> "/opt/freescale/buildroot/output/target/usr/lib/python2.7/site-packages/cffi/api.py",
>> line 56, in __init__
>>     import _cffi_backend as backend
>> ImportError:
>> /opt/freescale/buildroot/output/target/usr/lib/python2.7/site-packages/_cffi_backend.so:
>> wrong ELF class: ELFCLASS32
>> make: ***
>> [/opt/freescale/buildroot/output/build/python-smbus-cffi-0.4.1/.stamp_built]
>> Error 1
>>
>> I include here the Buildroot scripts for installation, which should make it
>> easy to test for others. (I think the PYTHON_SMBUS_CFFI_INSTALL_TARGET_OPTS
>> = install is not needed, but it also fails without this)
>
> Looks like the problem with python-cryptography:
> https://github.com/pyca/cryptography/issues/1325 See the last post.

In this thread someone mentions a dirty workaround via installing cffi
on host: https://github.com/pyca/bcrypt/issues/34

Will try it, if I have enough time.