[Python-Dev] ctypes/utils.py problem

[Brett Cannon]

Could you file a bug at bugs.python.org, David, so we don't lose track of
this?

On Wed, Feb 8, 2012 at 18:03, David Goulet <dgoulet at efficios.com> wrote:

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> Hi everyone,
>
> I'm working with the LTTng (Linux Tracing) team and we came across a
> problem
> with our user-space tracer and Python default behavior. We provide a libc
> wrapper that instrument free() and malloc() with a simple ld_preload of
> that lib.
>
> This lib *was* named "liblttng-ust-libc.so" and we came across python
> software
> registering to our trace registry daemon (meaning that somehow the python
> binary
> is using our in-process library). We dig a bit and found this:
>
> Lib/ctypes/utils.py:
>
> def _findLib_ldconfig(name):
>        # XXX assuming GLIBC's ldconfig (with option -p)
>        expr = r'/[^\(\)\s]*lib%s\.[^\(\)\s]*' % re.escape(name)
>        res = re.search(expr,
>                        os.popen('/sbin/ldconfig -p 2>/dev/null').read())
>
> and, at least, also found in _findLib_gcc(name) and
> _findSoname_ldconfig(name).
>
> This cause Python to use any library ending with "libc.so" to be loaded....
>
> I don't know the reasons behind this but we are concerned about "future
> issues"
> that can occur with this kind of behavior.
>
> For now, we renamed our lib so everything is fine.
>
> Thanks a lot guys.
> David
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