Add a |python| wrapper script which sets the right environment variables... #1
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…les and invokes /data/python/bin/python.
Crucially, the wrapper script sets LD_PRELOAD=libpython2.7.so. Without
this, we can't load any of the libs in lib-dynload, which means that we
can't import any Python module which uses native code (e.g. the select
module).
Without LD_PRELOAD, we get an error like the following when we try to
import a module which uses native code:
>>> import subprocess
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/data/python/lib/python2.7/subprocess.py", line 429, in <module>
import select
ImportError: Cannot load library: reloc_library[1285]: 9814 cannot locate 'PyDict_Next'...
The root problem is that the lib-dynload libraries do not have an
explicit dependency on libpython.so (see readelf -d), so therefore the
bionic linker doesn't try to resolve their symbols against libpython.
Setting this dependency would be the Right Fix.
You might want to pass an LD_LIBRARY_PATH to a child process of python, for example.
Contributor
Author
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One problem with this is that any subprocesses launched by Python will have libpython2.7.so LD_PRELOADED into them. That's not strictly correct, as it will cause the linker to prefer pulling from libpython2.7 instead of the child processes' solibs. But this is a small amount of breakage in comparison to not being able to import subprocess... |
st3fan
added a commit
that referenced
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Jan 21, 2013
Add a |python| wrapper script which sets the right environment variables...
Owner
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Thank you Justin! |
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... and invokes /data/python/bin/python.
Crucially, the wrapper script sets LD_PRELOAD=libpython2.7.so. Without
this, we can't load any of the libs in lib-dynload, which means that we
can't import any Python module which uses native code (e.g. the select
module).
Without LD_PRELOAD, we get an error like the following when we try to
import a module which uses native code:
The root problem is that the lib-dynload libraries do not have an
explicit dependency on libpython.so (see readelf -d), so therefore the
bionic linker doesn't try to resolve their symbols against libpython.
Setting this dependency would be the Right Fix.