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gh-76785: Avoid Pickled TracebackException for Propagated Subinterpreter Exceptions #113036

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Merged
merged 1 commit into from
Dec 13, 2023
Merged

gh-76785: Avoid Pickled TracebackException for Propagated Subinterpreter Exceptions #113036

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3 changes: 1 addition & 2 deletions Include/internal/pycore_crossinterp.h
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Original file line number Diff line number Diff line change
Expand Up @@ -188,8 +188,7 @@ typedef struct _excinfo {
const char *module;
} type;
const char *msg;
const char *pickled;
Py_ssize_t pickled_len;
const char *errdisplay;
} _PyXI_excinfo;


Expand Down
2 changes: 1 addition & 1 deletion Lib/test/support/interpreters/__init__.py
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Expand Up @@ -56,7 +56,7 @@ def __init__(self, excinfo):

def __str__(self):
try:
formatted = ''.join(self.excinfo.tbexc.format()).rstrip()
formatted = self.excinfo.errdisplay
except Exception:
return super().__str__()
else:
Expand Down
239 changes: 88 additions & 151 deletions Python/crossinterp.c
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Original file line number Diff line number Diff line change
Expand Up @@ -945,113 +945,105 @@ _xidregistry_fini(struct _xidregistry *registry)
/*************************/

static const char *
_copy_raw_string(const char *str, Py_ssize_t len)
_copy_string_obj_raw(PyObject *strobj, Py_ssize_t *p_size)
{
size_t size = len + 1;
if (len <= 0) {
size = strlen(str) + 1;
}
char *copied = PyMem_RawMalloc(size);
if (copied == NULL) {
return NULL;
}
if (len <= 0) {
strcpy(copied, str);
}
else {
memcpy(copied, str, size);
}
return copied;
}

static const char *
_copy_string_obj_raw(PyObject *strobj)
{
const char *str = PyUnicode_AsUTF8(strobj);
Py_ssize_t size = -1;
const char *str = PyUnicode_AsUTF8AndSize(strobj, &size);
if (str == NULL) {
return NULL;
}

char *copied = PyMem_RawMalloc(strlen(str)+1);
char *copied = PyMem_RawMalloc(size+1);
if (copied == NULL) {
PyErr_NoMemory();
return NULL;
}
strcpy(copied, str);
if (p_size != NULL) {
*p_size = size;
}
return copied;
}


static int
_pickle_object(PyObject *obj, const char **p_pickled, Py_ssize_t *p_len)
_convert_exc_to_TracebackException(PyObject *exc, PyObject **p_tbexc)
{
assert(!PyErr_Occurred());
PyObject *picklemod = PyImport_ImportModule("_pickle");
if (picklemod == NULL) {
PyErr_Clear();
picklemod = PyImport_ImportModule("pickle");
if (picklemod == NULL) {
return -1;
}
PyObject *args = NULL;
PyObject *kwargs = NULL;
PyObject *create = NULL;

// This is inspired by _PyErr_Display().
PyObject *tbmod = PyImport_ImportModule("traceback");
if (tbmod == NULL) {
return -1;
}
PyObject *dumps = PyObject_GetAttrString(picklemod, "dumps");
Py_DECREF(picklemod);
if (dumps == NULL) {
PyObject *tbexc_type = PyObject_GetAttrString(tbmod, "TracebackException");
Py_DECREF(tbmod);
if (tbexc_type == NULL) {
return -1;
}
PyObject *pickledobj = PyObject_CallOneArg(dumps, obj);
Py_DECREF(dumps);
if (pickledobj == NULL) {
create = PyObject_GetAttrString(tbexc_type, "from_exception");
Py_DECREF(tbexc_type);
if (create == NULL) {
return -1;
}

char *pickled = NULL;
Py_ssize_t len = 0;
if (PyBytes_AsStringAndSize(pickledobj, &pickled, &len) < 0) {
Py_DECREF(pickledobj);
return -1;
args = PyTuple_Pack(1, exc);
if (args == NULL) {
goto error;
}
const char *copied = _copy_raw_string(pickled, len);
Py_DECREF(pickledobj);
if (copied == NULL) {
return -1;

kwargs = PyDict_New();
if (kwargs == NULL) {
goto error;
}
if (PyDict_SetItemString(kwargs, "save_exc_type", Py_False) < 0) {
goto error;
}
if (PyDict_SetItemString(kwargs, "lookup_lines", Py_False) < 0) {
goto error;
}

PyObject *tbexc = PyObject_Call(create, args, kwargs);
Py_DECREF(args);
Py_DECREF(kwargs);
Py_DECREF(create);
if (tbexc == NULL) {
goto error;
}

*p_pickled = copied;
*p_len = len;
*p_tbexc = tbexc;
return 0;

error:
Py_XDECREF(args);
Py_XDECREF(kwargs);
Py_XDECREF(create);
return -1;
}

static int
_unpickle_object(const char *pickled, Py_ssize_t size, PyObject **p_obj)

static const char *
_format_TracebackException(PyObject *tbexc)
{
assert(!PyErr_Occurred());
PyObject *picklemod = PyImport_ImportModule("_pickle");
if (picklemod == NULL) {
PyErr_Clear();
picklemod = PyImport_ImportModule("pickle");
if (picklemod == NULL) {
return -1;
}
}
PyObject *loads = PyObject_GetAttrString(picklemod, "loads");
Py_DECREF(picklemod);
if (loads == NULL) {
return -1;
}
PyObject *pickledobj = PyBytes_FromStringAndSize(pickled, size);
if (pickledobj == NULL) {
Py_DECREF(loads);
return -1;
PyObject *lines = PyObject_CallMethod(tbexc, "format", NULL);
if (lines == NULL) {
return NULL;
}
PyObject *obj = PyObject_CallOneArg(loads, pickledobj);
Py_DECREF(loads);
Py_DECREF(pickledobj);
if (obj == NULL) {
return -1;
PyObject *formatted_obj = PyUnicode_Join(&_Py_STR(empty), lines);
Py_DECREF(lines);
if (formatted_obj == NULL) {
return NULL;
}
*p_obj = obj;
return 0;

Py_ssize_t size = -1;
const char *formatted = _copy_string_obj_raw(formatted_obj, &size);
Py_DECREF(formatted_obj);
// We remove trailing the newline added by TracebackException.format().
assert(formatted[size-1] == '\n');
((char *)formatted)[size-1] = '\0';
return formatted;
}


Expand Down Expand Up @@ -1101,7 +1093,7 @@ _excinfo_init_type(struct _excinfo_type *info, PyObject *exc)
if (strobj == NULL) {
return -1;
}
info->name = _copy_string_obj_raw(strobj);
info->name = _copy_string_obj_raw(strobj, NULL);
Py_DECREF(strobj);
if (info->name == NULL) {
return -1;
Expand All @@ -1112,7 +1104,7 @@ _excinfo_init_type(struct _excinfo_type *info, PyObject *exc)
if (strobj == NULL) {
return -1;
}
info->qualname = _copy_string_obj_raw(strobj);
info->qualname = _copy_string_obj_raw(strobj, NULL);
Py_DECREF(strobj);
if (info->name == NULL) {
return -1;
Expand All @@ -1123,7 +1115,7 @@ _excinfo_init_type(struct _excinfo_type *info, PyObject *exc)
if (strobj == NULL) {
return -1;
}
info->module = _copy_string_obj_raw(strobj);
info->module = _copy_string_obj_raw(strobj, NULL);
Py_DECREF(strobj);
if (info->name == NULL) {
return -1;
Expand Down Expand Up @@ -1188,8 +1180,8 @@ _PyXI_excinfo_Clear(_PyXI_excinfo *info)
if (info->msg != NULL) {
PyMem_RawFree((void *)info->msg);
}
if (info->pickled != NULL) {
PyMem_RawFree((void *)info->pickled);
if (info->errdisplay != NULL) {
PyMem_RawFree((void *)info->errdisplay);
}
*info = (_PyXI_excinfo){{NULL}};
}
Expand Down Expand Up @@ -1226,63 +1218,6 @@ _PyXI_excinfo_format(_PyXI_excinfo *info)
}
}

static int
_convert_exc_to_TracebackException(PyObject *exc, PyObject **p_tbexc)
{
PyObject *args = NULL;
PyObject *kwargs = NULL;
PyObject *create = NULL;

// This is inspired by _PyErr_Display().
PyObject *tbmod = PyImport_ImportModule("traceback");
if (tbmod == NULL) {
return -1;
}
PyObject *tbexc_type = PyObject_GetAttrString(tbmod, "TracebackException");
Py_DECREF(tbmod);
if (tbexc_type == NULL) {
return -1;
}
create = PyObject_GetAttrString(tbexc_type, "from_exception");
Py_DECREF(tbexc_type);
if (create == NULL) {
return -1;
}

args = PyTuple_Pack(1, exc);
if (args == NULL) {
goto error;
}

kwargs = PyDict_New();
if (kwargs == NULL) {
goto error;
}
if (PyDict_SetItemString(kwargs, "save_exc_type", Py_False) < 0) {
goto error;
}
if (PyDict_SetItemString(kwargs, "lookup_lines", Py_False) < 0) {
goto error;
}

PyObject *tbexc = PyObject_Call(create, args, kwargs);
Py_DECREF(args);
Py_DECREF(kwargs);
Py_DECREF(create);
if (tbexc == NULL) {
goto error;
}

*p_tbexc = tbexc;
return 0;

error:
Py_XDECREF(args);
Py_XDECREF(kwargs);
Py_XDECREF(create);
return -1;
}

static const char *
_PyXI_excinfo_InitFromException(_PyXI_excinfo *info, PyObject *exc)
{
Expand All @@ -1305,7 +1240,7 @@ _PyXI_excinfo_InitFromException(_PyXI_excinfo *info, PyObject *exc)
failure = "error while formatting exception";
goto error;
}
info->msg = _copy_string_obj_raw(msgobj);
info->msg = _copy_string_obj_raw(msgobj, NULL);
Py_DECREF(msgobj);
if (info->msg == NULL) {
failure = "error while copying exception message";
Expand All @@ -1321,13 +1256,14 @@ _PyXI_excinfo_InitFromException(_PyXI_excinfo *info, PyObject *exc)
PyErr_Clear();
}
else {
if (_pickle_object(tbexc, &info->pickled, &info->pickled_len) < 0) {
info->errdisplay = _format_TracebackException(tbexc);
Py_DECREF(tbexc);
if (info->errdisplay == NULL) {
#ifdef Py_DEBUG
PyErr_FormatUnraisable("Exception ignored while pickling TracebackException");
PyErr_FormatUnraisable("Exception ignored while formating TracebackException");
#endif
PyErr_Clear();
}
Py_DECREF(tbexc);
}

return NULL;
Expand All @@ -1342,8 +1278,9 @@ static void
_PyXI_excinfo_Apply(_PyXI_excinfo *info, PyObject *exctype)
{
PyObject *tbexc = NULL;
if (info->pickled != NULL) {
if (_unpickle_object(info->pickled, info->pickled_len, &tbexc) < 0) {
if (info->errdisplay != NULL) {
tbexc = PyUnicode_FromString(info->errdisplay);
if (tbexc == NULL) {
PyErr_Clear();
}
}
Expand All @@ -1354,9 +1291,9 @@ _PyXI_excinfo_Apply(_PyXI_excinfo *info, PyObject *exctype)

if (tbexc != NULL) {
PyObject *exc = PyErr_GetRaisedException();
if (PyObject_SetAttrString(exc, "_tbexc", tbexc) < 0) {
if (PyObject_SetAttrString(exc, "_errdisplay", tbexc) < 0) {
#ifdef Py_DEBUG
PyErr_FormatUnraisable("Exception ignored when setting _tbexc");
PyErr_FormatUnraisable("Exception ignored when setting _errdisplay");
#endif
PyErr_Clear();
}
Expand Down Expand Up @@ -1468,13 +1405,13 @@ _PyXI_excinfo_AsObject(_PyXI_excinfo *info)
goto error;
}

if (info->pickled != NULL) {
PyObject *tbexc = NULL;
if (_unpickle_object(info->pickled, info->pickled_len, &tbexc) < 0) {
if (info->errdisplay != NULL) {
PyObject *tbexc = PyUnicode_FromString(info->errdisplay);
if (tbexc == NULL) {
PyErr_Clear();
}
else {
res = PyObject_SetAttrString(ns, "tbexc", tbexc);
res = PyObject_SetAttrString(ns, "errdisplay", tbexc);
Py_DECREF(tbexc);
if (res < 0) {
goto error;
Expand Down Expand Up @@ -1646,7 +1583,7 @@ _sharednsitem_is_initialized(_PyXI_namespace_item *item)
static int
_sharednsitem_init(_PyXI_namespace_item *item, PyObject *key)
{
item->name = _copy_string_obj_raw(key);
item->name = _copy_string_obj_raw(key, NULL);
if (item->name == NULL) {
assert(!_sharednsitem_is_initialized(item));
return -1;
Expand Down