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gh-99537: Use Py_SETREF() function in C code (#99656) 

Fix potential race condition in code patterns:

* Replace "Py_DECREF(var); var = new;" with "Py_SETREF(var, new);"
* Replace "Py_XDECREF(var); var = new;" with "Py_XSETREF(var, new);"
* Replace "Py_CLEAR(var); var = new;" with "Py_XSETREF(var, new);"

Other changes:

* Replace "old = var; var = new; Py_DECREF(var)"
  with "Py_SETREF(var, new);"
* Replace "old = var; var = new; Py_XDECREF(var)"
  with "Py_XSETREF(var, new);"
* And remove the "old" variable.
This commit is contained in:
Victor Stinner 2022-11-22 14:22:22 +01:00 committed by GitHub
parent 135ec7cefb
commit 7e3f09cad9
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
20 changed files with 37 additions and 89 deletions
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10
Doc/includes/custom2.c
View File

@ -42,7 +42,7 @@ static int
Custom_init(CustomObject *self, PyObject *args, PyObject *kwds)
{
static char *kwlist[] = {"first", "last", "number", NULL};
PyObject *first = NULL, *last = NULL, *tmp;
PyObject *first = NULL, *last = NULL;
if (!PyArg_ParseTupleAndKeywords(args, kwds, "|OOi", kwlist,
&first, &last,
@ -50,14 +50,10 @@ Custom_init(CustomObject *self, PyObject *args, PyObject *kwds)
return -1;
if (first) {
tmp = self->first;
self->first = Py_NewRef(first);
Py_XDECREF(tmp);
Py_XSETREF(self->first, Py_NewRef(first));
}
if (last) {
tmp = self->last;
self->last = Py_NewRef(last);
Py_XDECREF(tmp);
Py_XSETREF(self->last, Py_NewRef(last));
}
return 0;
}

20
Doc/includes/custom3.c
View File

@ -42,7 +42,7 @@ static int
Custom_init(CustomObject *self, PyObject *args, PyObject *kwds)
{
static char *kwlist[] = {"first", "last", "number", NULL};
PyObject *first = NULL, *last = NULL, *tmp;
PyObject *first = NULL, *last = NULL;
if (!PyArg_ParseTupleAndKeywords(args, kwds, "|UUi", kwlist,
&first, &last,
@ -50,14 +50,10 @@ Custom_init(CustomObject *self, PyObject *args, PyObject *kwds)
return -1;
if (first) {
tmp = self->first;
self->first = Py_NewRef(first);
Py_DECREF(tmp);
Py_SETREF(self->first, Py_NewRef(first));
}
if (last) {
tmp = self->last;
self->last = Py_NewRef(last);
Py_DECREF(tmp);
Py_SETREF(self->last, Py_NewRef(last));
}
return 0;
}
@ -77,7 +73,6 @@ Custom_getfirst(CustomObject *self, void *closure)
static int
Custom_setfirst(CustomObject *self, PyObject *value, void *closure)
{
PyObject *tmp;
if (value == NULL) {
PyErr_SetString(PyExc_TypeError, "Cannot delete the first attribute");
return -1;
@ -87,9 +82,7 @@ Custom_setfirst(CustomObject *self, PyObject *value, void *closure)
"The first attribute value must be a string");
return -1;
}
tmp = self->first;
self->first = Py_NewRef(value);
Py_DECREF(tmp);
Py_SETREF(self->first, Py_NewRef(value));
return 0;
}
@ -102,7 +95,6 @@ Custom_getlast(CustomObject *self, void *closure)
static int
Custom_setlast(CustomObject *self, PyObject *value, void *closure)
{
PyObject *tmp;
if (value == NULL) {
PyErr_SetString(PyExc_TypeError, "Cannot delete the last attribute");
return -1;
@ -112,9 +104,7 @@ Custom_setlast(CustomObject *self, PyObject *value, void *closure)
"The last attribute value must be a string");
return -1;
}
tmp = self->last;
self->last = Py_NewRef(value);
Py_DECREF(tmp);
Py_SETREF(self->last, Py_NewRef(value));
return 0;
}

18
Doc/includes/custom4.c
View File

@ -58,7 +58,7 @@ static int
Custom_init(CustomObject *self, PyObject *args, PyObject *kwds)
{
static char *kwlist[] = {"first", "last", "number", NULL};
PyObject *first = NULL, *last = NULL, *tmp;
PyObject *first = NULL, *last = NULL;
if (!PyArg_ParseTupleAndKeywords(args, kwds, "|UUi", kwlist,
&first, &last,
@ -66,14 +66,10 @@ Custom_init(CustomObject *self, PyObject *args, PyObject *kwds)
return -1;
if (first) {
tmp = self->first;
self->first = Py_NewRef(first);
Py_DECREF(tmp);
Py_SETREF(self->first, Py_NewRef(first));
}
if (last) {
tmp = self->last;
self->last = Py_NewRef(last);
Py_DECREF(tmp);
Py_SETREF(self->last, Py_NewRef(last));
}
return 0;
}
@ -102,9 +98,7 @@ Custom_setfirst(CustomObject *self, PyObject *value, void *closure)
"The first attribute value must be a string");
return -1;
}
Py_INCREF(value);
Py_CLEAR(self->first);
self->first = value;
Py_XSETREF(self->first, Py_NewRef(value));
return 0;
}
@ -126,9 +120,7 @@ Custom_setlast(CustomObject *self, PyObject *value, void *closure)
"The last attribute value must be a string");
return -1;
}
Py_INCREF(value);
Py_CLEAR(self->last);
self->last = value;
Py_XSETREF(self->last, Py_NewRef(value));
return 0;
}

5
Modules/_collectionsmodule.c
View File

@ -1256,7 +1256,6 @@ deque_remove(dequeobject *deque, PyObject *value)
static int
deque_ass_item(dequeobject *deque, Py_ssize_t i, PyObject *v)
{
PyObject *old_value;
block *b;
Py_ssize_t n, len=Py_SIZE(deque), halflen=(len+1)>>1, index=i;
@ -1282,9 +1281,7 @@ deque_ass_item(dequeobject *deque, Py_ssize_t i, PyObject *v)
while (--n >= 0)
b = b->leftlink;
}
old_value = b->data[i];
b->data[i] = Py_NewRef(v);
Py_DECREF(old_value);
Py_SETREF(b->data[i], Py_NewRef(v));
return 0;
}

8
Modules/_datetimemodule.c
View File

@ -6247,13 +6247,10 @@ datetime_astimezone(PyDateTime_DateTime *self, PyObject *args, PyObject *kw)
}
else {
/* Result is already aware - just replace tzinfo. */
temp = result->tzinfo;
result->tzinfo = Py_NewRef(PyDateTime_TimeZone_UTC);
Py_DECREF(temp);
Py_SETREF(result->tzinfo, Py_NewRef(PyDateTime_TimeZone_UTC));
}
/* Attach new tzinfo and let fromutc() do the rest. */
temp = result->tzinfo;
if (tzinfo == Py_None) {
tzinfo = local_timezone(result);
if (tzinfo == NULL) {
@ -6263,8 +6260,7 @@ datetime_astimezone(PyDateTime_DateTime *self, PyObject *args, PyObject *kw)
}
else
Py_INCREF(tzinfo);
result->tzinfo = tzinfo;
Py_DECREF(temp);
Py_SETREF(result->tzinfo, tzinfo);
temp = (PyObject *)result;
result = (PyDateTime_DateTime *)

6
Modules/_elementtree.c
View File

@ -537,8 +537,7 @@ element_get_text(ElementObject* self)
if (!tmp)
return NULL;
self->text = tmp;
Py_DECREF(res);
res = tmp;
Py_SETREF(res, tmp);
}
}
@ -559,8 +558,7 @@ element_get_tail(ElementObject* self)
if (!tmp)
return NULL;
self->tail = tmp;
Py_DECREF(res);
res = tmp;
Py_SETREF(res, tmp);
}
}

3
Modules/_functoolsmodule.c
View File

@ -1243,8 +1243,7 @@ lru_cache_clear_list(lru_list_elem *link)
{
while (link != NULL) {
lru_list_elem *next = link->next;
Py_DECREF(link);
link = next;
Py_SETREF(link, next);
}
}

3
Modules/_io/stringio.c
View File

@ -193,8 +193,7 @@ write_str(stringio *self, PyObject *obj)
if (self->writenl) {
PyObject *translated = PyUnicode_Replace(
decoded, &_Py_STR(newline), self->writenl, -1);
Py_DECREF(decoded);
decoded = translated;
Py_SETREF(decoded, translated);
}
if (decoded == NULL)
return -1;

9
Modules/_io/textio.c
View File

@ -320,8 +320,7 @@ _PyIncrementalNewlineDecoder_decode(PyObject *myself,
out = PyUnicode_DATA(modified);
PyUnicode_WRITE(kind, out, 0, '\r');
memcpy(out + kind, PyUnicode_DATA(output), kind * output_len);
Py_DECREF(output);
output = modified; /* output remains ready */
Py_SETREF(output, modified); /* output remains ready */
self->pendingcr = 0;
output_len++;
}
@ -336,8 +335,7 @@ _PyIncrementalNewlineDecoder_decode(PyObject *myself,
PyObject *modified = PyUnicode_Substring(output, 0, output_len -1);
if (modified == NULL)
goto error;
Py_DECREF(output);
output = modified;
Py_SETREF(output, modified);
self->pendingcr = 1;
}
}
@ -865,8 +863,7 @@ _textiowrapper_set_decoder(textio *self, PyObject *codec_info,
self->decoder, self->readtranslate ? Py_True : Py_False, NULL);
if (incrementalDecoder == NULL)
return -1;
Py_CLEAR(self->decoder);
self->decoder = incrementalDecoder;
Py_XSETREF(self->decoder, incrementalDecoder);
}
return 0;

4
Modules/_json.c
View File

@ -709,9 +709,7 @@ _parse_object_unicode(PyScannerObject *s, PyObject *pystr, Py_ssize_t idx, Py_ss
if (memokey == NULL) {
goto bail;
}
Py_INCREF(memokey);
Py_DECREF(key);
key = memokey;
Py_SETREF(key, Py_NewRef(memokey));
idx = next_idx;
/* skip whitespace between key and : delimiter, read :, skip whitespace */

7
Modules/_pickle.c
View File

@ -1829,8 +1829,7 @@ get_deep_attribute(PyObject *obj, PyObject *names, PyObject **pparent)
n = PyList_GET_SIZE(names);
for (i = 0; i < n; i++) {
PyObject *name = PyList_GET_ITEM(names, i);
Py_XDECREF(parent);
parent = obj;
Py_XSETREF(parent, obj);
(void)_PyObject_LookupAttr(parent, name, &obj);
if (obj == NULL) {
Py_DECREF(parent);
@ -3717,9 +3716,7 @@ save_global(PicklerObject *self, PyObject *obj, PyObject *name)
else {
gen_global:
if (parent == module) {
Py_INCREF(lastname);
Py_DECREF(global_name);
global_name = lastname;
Py_SETREF(global_name, Py_NewRef(lastname));
}
if (self->proto >= 4) {
const char stack_global_op = STACK_GLOBAL;

3
Modules/_sqlite/cursor.c
View File

@ -1123,8 +1123,7 @@ pysqlite_cursor_iternext(pysqlite_Cursor *self)
PyObject *factory = self->row_factory;
PyObject *args[] = { (PyObject *)self, row, };
PyObject *new_row = PyObject_Vectorcall(factory, args, 2, NULL);
Py_DECREF(row);
row = new_row;
Py_SETREF(row, new_row);
}
return row;
}

3
Modules/_testinternalcapi.c
View File

@ -523,8 +523,7 @@ set_eval_frame_record(PyObject *self, PyObject *list)
PyErr_SetString(PyExc_TypeError, "argument must be a list");
return NULL;
}
Py_CLEAR(record_list);
record_list = Py_NewRef(list);
Py_XSETREF(record_list, Py_NewRef(list));
_PyInterpreterState_SetEvalFrameFunc(PyInterpreterState_Get(), record_eval);
Py_RETURN_NONE;
}

3
Modules/_tkinter.c
View File

@ -1105,8 +1105,7 @@ fromBignumObj(TkappObject *tkapp, Tcl_Obj *value)
PyMem_Free(bytes);
if (res != NULL && bigValue.sign == MP_NEG) {
PyObject *res2 = PyNumber_Negative(res);
Py_DECREF(res);
res = res2;
Py_SETREF(res, res2);
}
mp_clear(&bigValue);
return res;

3
Modules/_zoneinfo.c
View File

@ -1074,8 +1074,7 @@ load_data(PyZoneInfo_ZoneInfo *self, PyObject *file_obj)
// that the dstoff is set correctly in that case.
if (PyObject_IsTrue(tti->dstoff)) {
_ttinfo *tti_after = &(self->tzrule_after.std);
Py_DECREF(tti_after->dstoff);
tti_after->dstoff = Py_NewRef(tti->dstoff);
Py_SETREF(tti_after->dstoff, Py_NewRef(tti->dstoff));
}
}

3
Modules/audioop.c
View File

@ -1471,8 +1471,7 @@ audioop_ratecv_impl(PyObject *module, Py_buffer *fragment, int width,
len = (Py_ssize_t)(ncp - PyBytes_AsString(str));
rv = PyBytes_FromStringAndSize
(PyBytes_AsString(str), len);
Py_DECREF(str);
str = rv;
Py_SETREF(str, rv);
if (str == NULL)
goto exit;
rv = Py_BuildValue("(O(iO))", str, d, samps);

6
Modules/cjkcodecs/multibytecodec.c
View File

@ -980,8 +980,7 @@ _multibytecodec_MultibyteIncrementalEncoder_setstate_impl(MultibyteIncrementalEn
goto errorexit;
}
Py_CLEAR(self->pending);
self->pending = pending;
Py_XSETREF(self->pending, pending);
memcpy(self->state.c, statebytes+1+statebytes[0],
sizeof(self->state.c));
@ -1438,8 +1437,7 @@ mbstreamreader_iread(MultibyteStreamReaderObject *self,
memcpy(ctrdata + self->pendingsize,
PyBytes_AS_STRING(cres),
PyBytes_GET_SIZE(cres));
Py_DECREF(cres);
cres = ctr;
Py_SETREF(cres, ctr);
self->pendingsize = 0;
}

3
Modules/itertoolsmodule.c
View File

@ -834,8 +834,7 @@ teedataobject_safe_decref(PyObject *obj)
Py_REFCNT(obj) == 1) {
PyObject *nextlink = ((teedataobject *)obj)->nextlink;
((teedataobject *)obj)->nextlink = NULL;
Py_DECREF(obj);
obj = nextlink;
Py_SETREF(obj, nextlink);
}
Py_XDECREF(obj);
}

6
Modules/mathmodule.c
View File

@ -2069,8 +2069,7 @@ factorial_odd_part(unsigned long n)
Py_DECREF(partial);
if (tmp == NULL)
goto error;
Py_DECREF(inner);
inner = tmp;
Py_SETREF(inner, tmp);
/* Now inner is the product of all odd integers j in the range (0,
n/2**i], giving the inner product in the formula above. */
@ -2078,8 +2077,7 @@ factorial_odd_part(unsigned long n)
tmp = PyNumber_Multiply(outer, inner);
if (tmp == NULL)
goto error;
Py_DECREF(outer);
outer = tmp;
Py_SETREF(outer, tmp);
}
Py_DECREF(inner);
return outer;

3
Modules/posixmodule.c
View File

@ -1202,8 +1202,7 @@ path_converter(PyObject *o, void *p)
}
/* still owns a reference to the original object */
Py_DECREF(o);
o = res;
Py_SETREF(o, res);
}
if (is_unicode) {