py₃.so₂ example

py₃.so₂.py

#!/usr/bin/env python3
from cffi import FFI
from textwrap import dedent
from os import getpid
from sys import version_info

if __name__ == '__main__':
    from sys import argv

    print('Host is: %s (%s)' % (version_info, getpid()))
    print("Running in host:")
    exec(argv[1], locals(), globals())

    ffi1, ffi2, ffi3 = FFI(), FFI(), FFI()

    # Python 1.5.0
    #DL_IMPORT(void) Py_Initialize Py_PROTO((void));
    #DL_IMPORT(int) PyRun_SimpleString Py_PROTO((char *));
    #DL_IMPORT(void) Py_Finalize Py_PROTO((void));
    #int Py_NoSiteFlag;
    ffi1.cdef('''
        void Py_Initialize(void);
        int PyRun_SimpleString(const char *);
        void Py_Finalize(void);
        int Py_NoSiteFlag;''')

    # Python 2.7.4
    #PyAPI_FUNC(void) Py_Initialize(void);
    #PyAPI_FUNC(int) PyRun_SimpleStringFlags(const char *, PyCompilerFlags *);
    #PyAPI_FUNC(void) Py_Finalize(void);
    #int Py_NoSiteFlag;
    ffi2.cdef('''
        void Py_Initialize(void);
        int PyRun_SimpleStringFlags(const char *, void *);
        void Py_Finalize(void);
        int Py_NoSiteFlag;''')

    # Python 3.4.1
    #PyAPI_FUNC(void) Py_Initialize(void);
    #PyAPI_FUNC(int) PyRun_SimpleStringFlags(const char *, PyCompilerFlags *);
    #PyAPI_FUNC(void) Py_Finalize(void);
    #int Py_NoSiteFlag;
    ffi3.cdef('''
        void Py_Initialize(void);
        int PyRun_SimpleStringFlags(const char *, void *);
        void Py_Finalize(void);
        int Py_NoSiteFlag;''')

    flags1 = ffi1.RTLD_DEEPBIND | ffi1.RTLD_LOCAL | ffi1.RTLD_LAZY
    flags2 = ffi2.RTLD_DEEPBIND | ffi2.RTLD_LOCAL | ffi2.RTLD_LAZY
    flags3 = ffi3.RTLD_DEEPBIND | ffi3.RTLD_LOCAL | ffi3.RTLD_LAZY

    pythons = {
          (1,5,0): (ffi1.dlopen("./libpython1.5.so", flags1),
                    lambda s, py: py.PyRun_SimpleString(s)),
          (2,7,4): (ffi2.dlopen("./libpython2.7.so", flags2),
                    lambda s, py: py.PyRun_SimpleStringFlags(s, ffi2.NULL)),
          (3,4,1): (ffi3.dlopen("./libpython3.4dm.so", flags3),
                    lambda s, py: py.PyRun_SimpleStringFlags(s, ffi3.NULL)), 
    }

    # don't run site nonsense
    for py, _ in pythons.values(): 
        py.Py_NoSiteFlag = 1

    # start each interpreter
    for py, _ in pythons.values(): 
        py.Py_Initialize()

    # check version & run code
    for py, run in pythons.values(): 
        run(str.encode(dedent('''
            try:
                from sys import version_info
                ver = version_info
            except ImportError:
                from sys import version # Python 1.5
                ver = version
            from os import getpid
            print('Slave is: %s (%s)' % (ver, getpid()))
        ''')), py)
        run(b'print("Running in slave:")', py)
        run(str.encode(argv[1]), py)

    # shut it down
    for py, run in pythons.values():
        py.Py_Finalize()

Try running with:

    python py3so2.py 'from random import choice; choice([True,True,False]) and execfile("py3so2.py")'
    python3 py3so2.py 'from random import choice; choice([True,True,False]) and execfile("py3so2.py")'