Hi Michael, On Wed, Jun 15, 2005 at 01:35:35PM +0100, Michael Hudson wrote:
if (ProfilerError == NULL) ProfilerError = PyErr_NewException("hotshot.ProfilerError", NULL, NULL); if (ProfilerError != NULL) { Py_INCREF(ProfilerError); PyModule_AddObject(module, "ProfilerError", ProfilerError); }
I think the Py_INCREF is needed here. The ProfilerError is a global variable that needs the extra reference. Otherwise, a malicious user could do "del _hotshot.ProfilerError" and have it garbage-collected under the feet of _hotshot.c which still uses it. What I don't get is how ProfilerError could fail to be NULL in the first 'if' above, but that's a different matter. While we're at strange refcounting problems, PyModule_AddObject() only decrefs its last argument if no error occurs. This is probably wrong. In general I've found that the C modules' init code is fragile. This might be due to the idea that it runs only once anyway, and global C-module objects are immortal anyway, so sloppiness sneaks in. But for example, the following is common: m = Py_InitModule3("xxx", NULL, module_doc); Py_INCREF(&Xxx_Type); PyModule_AddObject(m, "Xxx", (PyObject *)&Xxx_Type); This generates a segfault if Py_InitModule3() returns NULL (however rare that situation is). A bientot, Armin