diff --git a/Doc/c-api/init.rst b/Doc/c-api/init.rst index ba1c2852f0b..dd63dd013e3 100644 --- a/Doc/c-api/init.rst +++ b/Doc/c-api/init.rst @@ -567,6 +567,15 @@ Initializing and finalizing the interpreter customized Python that always runs in isolated mode using :c:func:`Py_RunMain`. +.. c:function:: int PyUnstable_AtExit(PyInterpreterState *interp, void (*func)(void *), void *data) + + Register an :mod:`atexit` callback for the target interpreter *interp*. + This is similar to :c:func:`Py_AtExit`, but takes an explicit interpreter and + data pointer for the callback. + + The :term:`GIL` must be held for *interp*. + + .. versionadded:: 3.13 Process-wide parameters ======================= diff --git a/Doc/c-api/sys.rst b/Doc/c-api/sys.rst index d6fca1a0b0a..c688afdca82 100644 --- a/Doc/c-api/sys.rst +++ b/Doc/c-api/sys.rst @@ -426,3 +426,7 @@ Process Control function registered last is called first. Each cleanup function will be called at most once. Since Python's internal finalization will have completed before the cleanup function, no Python APIs should be called by *func*. + + .. seealso:: + + :c:func:`PyUnstable_AtExit` for passing a ``void *data`` argument. diff --git a/Include/internal/pycore_atexit.h b/Include/internal/pycore_atexit.h index 507a5c03cbc..cde5b530baf 100644 --- a/Include/internal/pycore_atexit.h +++ b/Include/internal/pycore_atexit.h @@ -44,7 +44,6 @@ typedef struct { struct atexit_state { atexit_callback *ll_callbacks; - atexit_callback *last_ll_callback; // XXX The rest of the state could be moved to the atexit module state // and a low-level callback added for it during module exec. diff --git a/Misc/NEWS.d/next/C_API/2024-12-10-14-25-22.gh-issue-127791.YRw4GU.rst b/Misc/NEWS.d/next/C_API/2024-12-10-14-25-22.gh-issue-127791.YRw4GU.rst new file mode 100644 index 00000000000..70751f18f5c --- /dev/null +++ b/Misc/NEWS.d/next/C_API/2024-12-10-14-25-22.gh-issue-127791.YRw4GU.rst @@ -0,0 +1,2 @@ +Fix loss of callbacks after more than one call to +:c:func:`PyUnstable_AtExit`. diff --git a/Modules/_testcapimodule.c b/Modules/_testcapimodule.c index 26f68691e44..8d86b535eff 100644 --- a/Modules/_testcapimodule.c +++ b/Modules/_testcapimodule.c @@ -3353,6 +3353,53 @@ type_freeze(PyObject *module, PyObject *args) Py_RETURN_NONE; } +struct atexit_data { + int called; + PyThreadState *tstate; + PyInterpreterState *interp; +}; + +static void +atexit_callback(void *data) +{ + struct atexit_data *at_data = (struct atexit_data *)data; + // Ensure that the callback is from the same interpreter + assert(PyThreadState_Get() == at_data->tstate); + assert(PyInterpreterState_Get() == at_data->interp); + ++at_data->called; +} + +static PyObject * +test_atexit(PyObject *self, PyObject *Py_UNUSED(args)) +{ + PyThreadState *oldts = PyThreadState_Swap(NULL); + PyThreadState *tstate = Py_NewInterpreter(); + + struct atexit_data data = {0}; + data.tstate = PyThreadState_Get(); + data.interp = PyInterpreterState_Get(); + + int amount = 10; + for (int i = 0; i < amount; ++i) + { + int res = PyUnstable_AtExit(tstate->interp, atexit_callback, (void *)&data); + if (res < 0) { + Py_EndInterpreter(tstate); + PyThreadState_Swap(oldts); + PyErr_SetString(PyExc_RuntimeError, "atexit callback failed"); + return NULL; + } + } + + Py_EndInterpreter(tstate); + PyThreadState_Swap(oldts); + + if (data.called != amount) { + PyErr_SetString(PyExc_RuntimeError, "atexit callback not called"); + return NULL; + } + Py_RETURN_NONE; +} static PyMethodDef TestMethods[] = { {"set_errno", set_errno, METH_VARARGS}, @@ -3495,6 +3542,7 @@ static PyMethodDef TestMethods[] = { {"test_critical_sections", test_critical_sections, METH_NOARGS}, {"finalize_thread_hang", finalize_thread_hang, METH_O, NULL}, {"type_freeze", type_freeze, METH_VARARGS}, + {"test_atexit", test_atexit, METH_NOARGS}, {NULL, NULL} /* sentinel */ }; diff --git a/Modules/_testinternalcapi.c b/Modules/_testinternalcapi.c index 1bb71a3e80b..288daf09a5f 100644 --- a/Modules/_testinternalcapi.c +++ b/Modules/_testinternalcapi.c @@ -1236,39 +1236,6 @@ unicode_transformdecimalandspacetoascii(PyObject *self, PyObject *arg) return _PyUnicode_TransformDecimalAndSpaceToASCII(arg); } - -struct atexit_data { - int called; -}; - -static void -callback(void *data) -{ - ((struct atexit_data *)data)->called += 1; -} - -static PyObject * -test_atexit(PyObject *self, PyObject *Py_UNUSED(args)) -{ - PyThreadState *oldts = PyThreadState_Swap(NULL); - PyThreadState *tstate = Py_NewInterpreter(); - - struct atexit_data data = {0}; - int res = PyUnstable_AtExit(tstate->interp, callback, (void *)&data); - Py_EndInterpreter(tstate); - PyThreadState_Swap(oldts); - if (res < 0) { - return NULL; - } - - if (data.called == 0) { - PyErr_SetString(PyExc_RuntimeError, "atexit callback not called"); - return NULL; - } - Py_RETURN_NONE; -} - - static PyObject * test_pyobject_is_freed(const char *test_name, PyObject *op) { @@ -2128,7 +2095,6 @@ static PyMethodDef module_functions[] = { {"_PyTraceMalloc_GetTraceback", tracemalloc_get_traceback, METH_VARARGS}, {"test_tstate_capi", test_tstate_capi, METH_NOARGS, NULL}, {"_PyUnicode_TransformDecimalAndSpaceToASCII", unicode_transformdecimalandspacetoascii, METH_O}, - {"test_atexit", test_atexit, METH_NOARGS}, {"check_pyobject_forbidden_bytes_is_freed", check_pyobject_forbidden_bytes_is_freed, METH_NOARGS}, {"check_pyobject_freed_is_freed", check_pyobject_freed_is_freed, METH_NOARGS}, diff --git a/Modules/atexitmodule.c b/Modules/atexitmodule.c index 297a8d74ba3..c009235b7a3 100644 --- a/Modules/atexitmodule.c +++ b/Modules/atexitmodule.c @@ -27,7 +27,10 @@ int PyUnstable_AtExit(PyInterpreterState *interp, atexit_datacallbackfunc func, void *data) { - assert(interp == _PyInterpreterState_GET()); + PyThreadState *tstate = _PyThreadState_GET(); + _Py_EnsureTstateNotNULL(tstate); + assert(tstate->interp == interp); + atexit_callback *callback = PyMem_Malloc(sizeof(atexit_callback)); if (callback == NULL) { PyErr_NoMemory(); @@ -38,12 +41,13 @@ PyUnstable_AtExit(PyInterpreterState *interp, callback->next = NULL; struct atexit_state *state = &interp->atexit; - if (state->ll_callbacks == NULL) { + atexit_callback *top = state->ll_callbacks; + if (top == NULL) { state->ll_callbacks = callback; - state->last_ll_callback = callback; } else { - state->last_ll_callback->next = callback; + callback->next = top; + state->ll_callbacks = callback; } return 0; }