[pypy-dev] Making Pyrasite work with PyPy

[Maciej Fijalkowski]

Hi Tin

This is very much on topic for pypy-dev. One obvious solution would be
to check for the existance of symbols in gdb (if there is a symbol
called PyPyRun_SimpleString, then obviously you're running on PyPy).
I'm not sure how to express it under gdb, but there must be a way

On Sun, Mar 6, 2016 at 12:20 AM, Tin Tvrtković <tinchester at gmail.com> wrote:
> Hello,
>
> in case you haven't heard of it, Pyrasite
> (https://github.com/lmacken/pyrasite) is a tool for injecting code into
> running Python processes. Personally I have found it invaluable for
> forensics on services running in production and have successfully solved
> memory leaks, connection leaks and deadlocks with it. One of the
> payloads provided will open a remote REPL right in a running process,
> without the process having *any* preparation logic in it. I think this
> is extremely powerful and makes Python catch and up even surpass Java
> (which has automatic stack trace dumping on SIGQUIT and useful tools
> like JConsole and VisualVM that can connect to running processes, again
> by default with no setup in the process) for these kinds of things.
>
> Anyway, Pyrasite uses gdb under the hood; gdb will attach to a running
> process and inject the following:
>
>     gdb_cmds = [
>         'PyGILState_Ensure()',
>         'PyRun_SimpleString("'
>             'import sys; sys.path.insert(0, \\"%s\\"); '
>             'sys.path.insert(0, \\"%s\\"); '
>             'exec(open(\\"%s\\").read())")' %
>                 (os.path.dirname(filename),
>                 os.path.abspath(os.path.join(os.path.dirname(__file__),
> '..')),
>                 filename),
>         'PyGILState_Release($1)',
>         ]
>
> If I change the Py* functions to PyPy* (PyRun_SimpleString to
> PyPyRun_SimpleString), this seems to work just fine on PyPy too.
>
> This is great, and now I'd like to contribute back to Pyrasite and get
> PyPy support in there. It'd be great if Pyrasite could automatically
> detect if the underlying process is CPython or PyPy, so since my
> experience working on the C level is very basic, I'm asking you, the
> PyPy devs, if there's a good way of detecting a process is PyPy given
> its PID and gdb's ability of attaching to a process and doing gdb
> things. Worst case scenario, gdb supports "info functions", which is how
> I found the PyPy functions in the first place, but is there a better way?
>
> I apologize if this is off-topic for PyPy-dev.
>
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