Mercurial > cpython-lru_cache-weakref
view Python/modsupport.c @ 22621:830c829a7eb2 legacy-trunk
Fix an issue that was reported in but unrelated to the main problem of
SF bug 535905 (Evil Trashcan and GC interaction).
The SETLOCAL() macro should not DECREF the local variable in-place and
then store the new value; it should copy the old value to a temporary
value, then store the new value, and then DECREF the temporary value.
This is because it is possible that during the DECREF the frame is
accessed by other code (e.g. a __del__ method or gc.collect()) and the
variable would be pointing to already-freed memory.
BUGFIX CANDIDATE!
| author | Guido van Rossum <guido@python.org> |
|---|---|
| date | Thu, 28 Mar 2002 20:17:52 +0000 |
| parents | ddc9543c76a0 |
| children | 7b66f0034233 |
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/* Module support implementation */ #include "Python.h" #ifdef MPW /* MPW pushes 'extended' for float and double types with varargs */ typedef extended va_double; #else typedef double va_double; #endif /* Package context -- the full module name for package imports */ char *_Py_PackageContext = NULL; /* Py_InitModule4() parameters: - name is the module name - methods is the list of top-level functions - doc is the documentation string - passthrough is passed as self to functions defined in the module - api_version is the value of PYTHON_API_VERSION at the time the module was compiled Return value is a borrowed reference to the module object; or NULL if an error occurred (in Python 1.4 and before, errors were fatal). Errors may still leak memory. */ static char api_version_warning[] = "Python C API version mismatch for module %.100s:\ This Python has API version %d, module %.100s has version %d."; PyObject * Py_InitModule4(char *name, PyMethodDef *methods, char *doc, PyObject *passthrough, int module_api_version) { PyObject *m, *d, *v; PyMethodDef *ml; if (!Py_IsInitialized()) Py_FatalError("Interpreter not initialized (version mismatch?)"); if (module_api_version != PYTHON_API_VERSION) { char message[512]; PyOS_snprintf(message, sizeof(message), api_version_warning, name, PYTHON_API_VERSION, name, module_api_version); if (PyErr_Warn(PyExc_RuntimeWarning, message)) return NULL; } if (_Py_PackageContext != NULL) { char *p = strrchr(_Py_PackageContext, '.'); if (p != NULL && strcmp(name, p+1) == 0) { name = _Py_PackageContext; _Py_PackageContext = NULL; } } if ((m = PyImport_AddModule(name)) == NULL) return NULL; d = PyModule_GetDict(m); for (ml = methods; ml->ml_name != NULL; ml++) { if ((ml->ml_flags & METH_CLASS) || (ml->ml_flags & METH_STATIC)) { PyErr_SetString(PyExc_ValueError, "module functions cannot set" " METH_CLASS or METH_STATIC"); return NULL; } v = PyCFunction_New(ml, passthrough); if (v == NULL) return NULL; if (PyDict_SetItemString(d, ml->ml_name, v) != 0) { Py_DECREF(v); return NULL; } Py_DECREF(v); } if (doc != NULL) { v = PyString_FromString(doc); if (v == NULL || PyDict_SetItemString(d, "__doc__", v) != 0) { Py_DECREF(v); return NULL; } Py_DECREF(v); } return m; } /* Helper for mkvalue() to scan the length of a format */ static int countformat(char *format, int endchar) { int count = 0; int level = 0; while (level > 0 || *format != endchar) { switch (*format) { case '\0': /* Premature end */ PyErr_SetString(PyExc_SystemError, "unmatched paren in format"); return -1; case '(': case '[': case '{': if (level == 0) count++; level++; break; case ')': case ']': case '}': level--; break; case '#': case '&': case ',': case ':': case ' ': case '\t': break; default: if (level == 0) count++; } format++; } return count; } /* Generic function to create a value -- the inverse of getargs() */ /* After an original idea and first implementation by Steven Miale */ static PyObject *do_mktuple(char**, va_list *, int, int); static PyObject *do_mklist(char**, va_list *, int, int); static PyObject *do_mkdict(char**, va_list *, int, int); static PyObject *do_mkvalue(char**, va_list *); static PyObject * do_mkdict(char **p_format, va_list *p_va, int endchar, int n) { PyObject *d; int i; if (n < 0) return NULL; if ((d = PyDict_New()) == NULL) return NULL; for (i = 0; i < n; i+= 2) { PyObject *k, *v; int err; k = do_mkvalue(p_format, p_va); if (k == NULL) { Py_DECREF(d); return NULL; } v = do_mkvalue(p_format, p_va); if (v == NULL) { Py_DECREF(k); Py_DECREF(d); return NULL; } err = PyDict_SetItem(d, k, v); Py_DECREF(k); Py_DECREF(v); if (err < 0) { Py_DECREF(d); return NULL; } } if (d != NULL && **p_format != endchar) { Py_DECREF(d); d = NULL; PyErr_SetString(PyExc_SystemError, "Unmatched paren in format"); } else if (endchar) ++*p_format; return d; } static PyObject * do_mklist(char **p_format, va_list *p_va, int endchar, int n) { PyObject *v; int i; if (n < 0) return NULL; if ((v = PyList_New(n)) == NULL) return NULL; for (i = 0; i < n; i++) { PyObject *w = do_mkvalue(p_format, p_va); if (w == NULL) { Py_DECREF(v); return NULL; } PyList_SetItem(v, i, w); } if (v != NULL && **p_format != endchar) { Py_DECREF(v); v = NULL; PyErr_SetString(PyExc_SystemError, "Unmatched paren in format"); } else if (endchar) ++*p_format; return v; } #ifdef Py_USING_UNICODE static int _ustrlen(Py_UNICODE *u) { int i = 0; Py_UNICODE *v = u; while (*v != 0) { i++; v++; } return i; } #endif static PyObject * do_mktuple(char **p_format, va_list *p_va, int endchar, int n) { PyObject *v; int i; if (n < 0) return NULL; if ((v = PyTuple_New(n)) == NULL) return NULL; for (i = 0; i < n; i++) { PyObject *w = do_mkvalue(p_format, p_va); if (w == NULL) { Py_DECREF(v); return NULL; } PyTuple_SetItem(v, i, w); } if (v != NULL && **p_format != endchar) { Py_DECREF(v); v = NULL; PyErr_SetString(PyExc_SystemError, "Unmatched paren in format"); } else if (endchar) ++*p_format; return v; } static PyObject * do_mkvalue(char **p_format, va_list *p_va) { for (;;) { switch (*(*p_format)++) { case '(': return do_mktuple(p_format, p_va, ')', countformat(*p_format, ')')); case '[': return do_mklist(p_format, p_va, ']', countformat(*p_format, ']')); case '{': return do_mkdict(p_format, p_va, '}', countformat(*p_format, '}')); case 'b': case 'B': case 'h': case 'i': return PyInt_FromLong((long)va_arg(*p_va, int)); case 'H': return PyInt_FromLong((long)va_arg(*p_va, unsigned int)); case 'l': return PyInt_FromLong((long)va_arg(*p_va, long)); #ifdef HAVE_LONG_LONG case 'L': return PyLong_FromLongLong((LONG_LONG)va_arg(*p_va, LONG_LONG)); #endif #ifdef Py_USING_UNICODE case 'u': { PyObject *v; Py_UNICODE *u = va_arg(*p_va, Py_UNICODE *); int n; if (**p_format == '#') { ++*p_format; n = va_arg(*p_va, int); } else n = -1; if (u == NULL) { v = Py_None; Py_INCREF(v); } else { if (n < 0) n = _ustrlen(u); v = PyUnicode_FromUnicode(u, n); } return v; } #endif case 'f': case 'd': return PyFloat_FromDouble( (double)va_arg(*p_va, va_double)); #ifndef WITHOUT_COMPLEX case 'D': return PyComplex_FromCComplex( *((Py_complex *)va_arg(*p_va, Py_complex *))); #endif /* WITHOUT_COMPLEX */ case 'c': { char p[1]; p[0] = va_arg(*p_va, int); return PyString_FromStringAndSize(p, 1); } case 's': case 'z': { PyObject *v; char *str = va_arg(*p_va, char *); int n; if (**p_format == '#') { ++*p_format; n = va_arg(*p_va, int); } else n = -1; if (str == NULL) { v = Py_None; Py_INCREF(v); } else { if (n < 0) { size_t m = strlen(str); if (m > INT_MAX) { PyErr_SetString(PyExc_OverflowError, "string too long for Python string"); return NULL; } n = (int)m; } v = PyString_FromStringAndSize(str, n); } return v; } case 'N': case 'S': case 'O': if (**p_format == '&') { typedef PyObject *(*converter)(void *); converter func = va_arg(*p_va, converter); void *arg = va_arg(*p_va, void *); ++*p_format; return (*func)(arg); } else { PyObject *v; v = va_arg(*p_va, PyObject *); if (v != NULL) { if (*(*p_format - 1) != 'N') Py_INCREF(v); } else if (!PyErr_Occurred()) /* If a NULL was passed * because a call that should * have constructed a value * failed, that's OK, and we * pass the error on; but if * no error occurred it's not * clear that the caller knew * what she was doing. */ PyErr_SetString(PyExc_SystemError, "NULL object passed to Py_BuildValue"); return v; } case ':': case ',': case ' ': case '\t': break; default: PyErr_SetString(PyExc_SystemError, "bad format char passed to Py_BuildValue"); return NULL; } } } PyObject *Py_BuildValue(char *format, ...) { va_list va; PyObject* retval; va_start(va, format); retval = Py_VaBuildValue(format, va); va_end(va); return retval; } PyObject * Py_VaBuildValue(char *format, va_list va) { char *f = format; int n = countformat(f, '\0'); va_list lva; #ifdef VA_LIST_IS_ARRAY memcpy(lva, va, sizeof(va_list)); #else lva = va; #endif if (n < 0) return NULL; if (n == 0) { Py_INCREF(Py_None); return Py_None; } if (n == 1) return do_mkvalue(&f, &lva); return do_mktuple(&f, &lva, '\0', n); } PyObject * PyEval_CallFunction(PyObject *obj, char *format, ...) { va_list vargs; PyObject *args; PyObject *res; va_start(vargs, format); args = Py_VaBuildValue(format, vargs); va_end(vargs); if (args == NULL) return NULL; res = PyEval_CallObject(obj, args); Py_DECREF(args); return res; } PyObject * PyEval_CallMethod(PyObject *obj, char *methodname, char *format, ...) { va_list vargs; PyObject *meth; PyObject *args; PyObject *res; meth = PyObject_GetAttrString(obj, methodname); if (meth == NULL) return NULL; va_start(vargs, format); args = Py_VaBuildValue(format, vargs); va_end(vargs); if (args == NULL) { Py_DECREF(meth); return NULL; } res = PyEval_CallObject(meth, args); Py_DECREF(meth); Py_DECREF(args); return res; } int PyModule_AddObject(PyObject *m, char *name, PyObject *o) { PyObject *dict; if (!PyModule_Check(m) || o == NULL) return -1; dict = PyModule_GetDict(m); if (dict == NULL) return -1; if (PyDict_SetItemString(dict, name, o)) return -1; Py_DECREF(o); return 0; } int PyModule_AddIntConstant(PyObject *m, char *name, long value) { return PyModule_AddObject(m, name, PyInt_FromLong(value)); } int PyModule_AddStringConstant(PyObject *m, char *name, char *value) { return PyModule_AddObject(m, name, PyString_FromString(value)); }
