https://github.com/njsmith/test-link-namespaces

https://github.com/njsmith/test-link-namespaces

Last synced: 7 days ago
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• Host: GitHub
• URL: https://github.com/njsmith/test-link-namespaces
• Owner: njsmith
• Created: 2016-02-08T06:09:09.000Z (over 10 years ago)
• Default Branch: master
• Last Pushed: 2016-02-08T06:10:12.000Z (over 10 years ago)
• Last Synced: 2025-10-19T17:38:54.405Z (9 months ago)
• Language: C
• Size: 151 KB
• Stars: 0
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.rst

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README

          
Small repo for testing how ``dlopen`` namespaces work in Linux/ELF.

``_regex.so`` is a small Python extension taken from a Debian system,

that does not explictly link to ``libpython2.7.so.1``.

``linktest.c`` and ``plugin.c`` together make some programs to check

how different ways of linking and running Python extensions work.

::

   $ ./build.sh

   $ ./linktest-with-python

   Checking for a priori presence of python...

   FOUND: we were linked with -lpython

   Using dlopen to load libpython

   Using dlopen to load a python extension

   Initializing dlopen'ed python interpreter

     (hello world from dlopen embedded python!)

     Address of True is 7fcfa37f49f0

   Using dlopen'ed python interpreter to load a non-existent module

   Traceback (most recent call last):

     File "", line 1, in 

   ImportError: No module named nosuchmodule

   ...failed, as expected

   Using dlopen'ed python interpreter to load an extension module

   ...succeeded

   Running in plugin:

     (hello world from plugin embedded python!)

     Address of True is 7fcfa37f49f0

   Plugin attempting to load a non-existent module

   Traceback (most recent call last):

     File "", line 1, in 

   ImportError: No module named nosuchmodule

   ...failed, as expected

   Plugin attempting to load an extension module

   ...succeeded

   $ ./linktest-no-python

   Checking for a priori presence of python...

   NOT FOUND: we were NOT linked with -lpython

   Using dlopen to load libpython

   Using dlopen to load a python extension

     dlopen error: _regex: ./_regex.so: undefined symbol: _Py_ZeroStruct

   Initializing dlopen'ed python interpreter

     (hello world from dlopen embedded python!)

     Address of True is 7f7f9ef0d9f0

   Using dlopen'ed python interpreter to load a non-existent module

   Traceback (most recent call last):

     File "", line 1, in 

   ImportError: No module named nosuchmodule

   ...failed, as expected

   Using dlopen'ed python interpreter to load an extension module

   Traceback (most recent call last):

     File "", line 1, in 

   ImportError: /home/njs/manylinux/link-namespaces/_regex.so: undefined symbol: _Py_ZeroStruct

   ...failed

   Running in plugin:

     (hello world from plugin embedded python!)

     Address of True is 7f7f9ef0d9f0

   Plugin attempting to load a non-existent module

   Traceback (most recent call last):

     File "", line 1, in 

   ImportError: No module named nosuchmodule

   ...failed, as expected

   Plugin attempting to load an extension module

   Traceback (most recent call last):

     File "", line 1, in 

   ImportError: /home/njs/manylinux/link-namespaces/_regex.so: undefined symbol: _Py_ZeroStruct

   ...failed

It's also interesting to run these with ``LD_DEBUG=scopes`` to get a

sense of what's going on.