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Issue #19255: The builtins module is restored to initial value before

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cleaning other modules.  The sys and builtins modules are cleaned last.
This commit is contained in:
Serhiy Storchaka 2014-02-10 18:21:34 +02:00
parent 8f9f0f12e8
commit 87a5c515d0
7 changed files with 96 additions and 39 deletions
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85
Python/import.c
View file

@ -49,9 +49,13 @@ class fs_unicode_converter(CConverter):
void
_PyImport_Init(void)
{
PyInterpreterState *interp = PyThreadState_Get()->interp;
initstr = PyUnicode_InternFromString("__init__");
if (initstr == NULL)
Py_FatalError("Can't initialize import variables");
interp->builtins_copy = PyDict_Copy(interp->builtins);
if (interp->builtins_copy == NULL)
Py_FatalError("Can't backup builtins dict");
}
void
@ -397,8 +401,10 @@ PyImport_Cleanup(void)
PyObject *key, *value, *dict;
PyInterpreterState *interp = PyThreadState_GET()->interp;
PyObject *modules = interp->modules;
PyObject *builtins = interp->builtins;
PyObject *builtins_mod = NULL;
PyObject *sys_mod = NULL;
PyObject *weaklist = NULL;
char **p;
if (modules == NULL)
return; /* Already done */
@ -411,31 +417,22 @@ PyImport_Cleanup(void)
/* XXX Perhaps these precautions are obsolete. Who knows? */
value = PyDict_GetItemString(modules, "builtins");
if (value != NULL && PyModule_Check(value)) {
dict = PyModule_GetDict(value);
if (Py_VerboseFlag)
PySys_WriteStderr("# clear builtins._\n");
PyDict_SetItemString(interp->builtins, "_", Py_None);
for (p = sys_deletes; *p != NULL; p++) {
if (Py_VerboseFlag)
PySys_WriteStderr("# clear builtins._\n");
PyDict_SetItemString(dict, "_", Py_None);
PySys_WriteStderr("# clear sys.%s\n", *p);
PyDict_SetItemString(interp->sysdict, *p, Py_None);
}
value = PyDict_GetItemString(modules, "sys");
if (value != NULL && PyModule_Check(value)) {
char **p;
PyObject *v;
dict = PyModule_GetDict(value);
for (p = sys_deletes; *p != NULL; p++) {
if (Py_VerboseFlag)
PySys_WriteStderr("# clear sys.%s\n", *p);
PyDict_SetItemString(dict, *p, Py_None);
}
for (p = sys_files; *p != NULL; p+=2) {
if (Py_VerboseFlag)
PySys_WriteStderr("# restore sys.%s\n", *p);
v = PyDict_GetItemString(dict, *(p+1));
if (v == NULL)
v = Py_None;
PyDict_SetItemString(dict, *p, v);
}
for (p = sys_files; *p != NULL; p+=2) {
if (Py_VerboseFlag)
PySys_WriteStderr("# restore sys.%s\n", *p);
value = PyDict_GetItemString(interp->sysdict, *(p+1));
if (value == NULL)
value = Py_None;
PyDict_SetItemString(interp->sysdict, *p, value);
}
/* We prepare a list which will receive (name, weakref) tuples of
@ -473,11 +470,15 @@ PyImport_Cleanup(void)
/* Clear the modules dict. */
PyDict_Clear(modules);
/* Replace the interpreter's reference to builtins with an empty dict
(module globals still have a reference to the original builtins). */
builtins = interp->builtins;
interp->builtins = PyDict_New();
Py_DECREF(builtins);
/* Restore the original builtins dict, to ensure that any
user data gets cleared. */
dict = PyDict_Copy(interp->builtins);
if (dict == NULL)
PyErr_Clear();
PyDict_Clear(interp->builtins);
if (PyDict_Update(interp->builtins, interp->builtins_copy))
PyErr_Clear();
Py_XDECREF(dict);
/* Clear module dict copies stored in the interpreter state */
_PyState_ClearModules();
/* Collect references */
@ -488,7 +489,15 @@ PyImport_Cleanup(void)
/* Now, if there are any modules left alive, clear their globals to
minimize potential leaks. All C extension modules actually end
up here, since they are kept alive in the interpreter state. */
up here, since they are kept alive in the interpreter state.
The special treatment of "builtins" here is because even
when it's not referenced as a module, its dictionary is
referenced by almost every module's __builtins__. Since
deleting a module clears its dictionary (even if there are
references left to it), we need to delete the "builtins"
module last. Likewise, we don't delete sys until the very
end because it is implicitly referenced (e.g. by print). */
if (weaklist != NULL) {
Py_ssize_t i, n;
n = PyList_GET_SIZE(weaklist);
@ -498,17 +507,27 @@ PyImport_Cleanup(void)
PyObject *mod = PyWeakref_GET_OBJECT(PyTuple_GET_ITEM(tup, 1));
if (mod == Py_None)
continue;
Py_INCREF(mod);
assert(PyModule_Check(mod));
dict = PyModule_GetDict(mod);
if (dict == interp->builtins || dict == interp->sysdict)
continue;
Py_INCREF(mod);
if (Py_VerboseFlag && PyUnicode_Check(name))
PySys_FormatStderr("# cleanup[3] wiping %U\n",
name, mod);
PySys_FormatStderr("# cleanup[3] wiping %U\n", name);
_PyModule_Clear(mod);
Py_DECREF(mod);
}
Py_DECREF(weaklist);
}
/* Next, delete sys and builtins (in that order) */
if (Py_VerboseFlag)
PySys_FormatStderr("# cleanup[3] wiping sys\n");
_PyModule_ClearDict(interp->sysdict);
if (Py_VerboseFlag)
PySys_FormatStderr("# cleanup[3] wiping builtins\n");
_PyModule_ClearDict(interp->builtins);
/* Clear and delete the modules directory. Actual modules will
still be there only if imported during the execution of some
destructor. */

2
Python/pystate.c
View file

@ -72,6 +72,7 @@ PyInterpreterState_New(void)
interp->modules_by_index = NULL;
interp->sysdict = NULL;
interp->builtins = NULL;
interp->builtins_copy = NULL;
interp->tstate_head = NULL;
interp->codec_search_path = NULL;
interp->codec_search_cache = NULL;
@ -115,6 +116,7 @@ PyInterpreterState_Clear(PyInterpreterState *interp)
Py_CLEAR(interp->modules_by_index);
Py_CLEAR(interp->sysdict);
Py_CLEAR(interp->builtins);
Py_CLEAR(interp->builtins_copy);
Py_CLEAR(interp->importlib);
}