[3.6] bpo-30808: Use _Py_atomic API for concurrency-sensitive signal state (GH-2417) by pitrou · Pull Request #3007 · python/cpython

Expand Up @@ -93,7 +93,7 @@ static pid_t main_pid; #endif
static volatile struct { sig_atomic_t tripped; _Py_atomic_int tripped; PyObject *func; } Handlers[NSIG];
Expand All @@ -113,7 +113,7 @@ static volatile sig_atomic_t wakeup_fd = -1; #endif
/* Speed up sigcheck() when none tripped */ static volatile sig_atomic_t is_tripped = 0; static _Py_atomic_int is_tripped;
static PyObject *DefaultHandler; static PyObject *IgnoreHandler; Expand Down Expand Up @@ -240,11 +240,13 @@ trip_signal(int sig_num) int fd; Py_ssize_t rc;
Handlers[sig_num].tripped = 1; _Py_atomic_store_relaxed(&Handlers[sig_num].tripped, 1);
/* Set is_tripped after setting .tripped, as it gets cleared in PyErr_CheckSignals() before .tripped. */ is_tripped = 1; _Py_atomic_store(&is_tripped, 1);
/* Notify ceval.c */ _PyEval_SignalReceived();
/* And then write to the wakeup fd *after* setting all the globals and Expand Down Expand Up @@ -465,7 +467,7 @@ signal_signal_impl(PyObject *module, int signalnum, PyObject *handler) return NULL; } old_handler = Handlers[signalnum].func; Handlers[signalnum].tripped = 0; _Py_atomic_store_relaxed(&Handlers[signalnum].tripped, 0); Py_INCREF(handler); Handlers[signalnum].func = handler; if (old_handler != NULL) Expand Down Expand Up @@ -1264,11 +1266,11 @@ PyInit__signal(void) goto finally; Py_INCREF(IntHandler);
Handlers[0].tripped = 0; _Py_atomic_store_relaxed(&Handlers[0].tripped, 0); for (i = 1; i < NSIG; i++) { void (*t)(int); t = PyOS_getsig(i); Handlers[i].tripped = 0; _Py_atomic_store_relaxed(&Handlers[i].tripped, 0); if (t == SIG_DFL) Handlers[i].func = DefaultHandler; else if (t == SIG_IGN) Expand Down Expand Up @@ -1492,7 +1494,7 @@ finisignal(void)
for (i = 1; i < NSIG; i++) { func = Handlers[i].func; Handlers[i].tripped = 0; _Py_atomic_store_relaxed(&Handlers[i].tripped, 0); Handlers[i].func = NULL; if (i != SIGINT && func != NULL && func != Py_None && func != DefaultHandler && func != IgnoreHandler) Expand All @@ -1513,7 +1515,7 @@ PyErr_CheckSignals(void) int i; PyObject *f;
if (!is_tripped) if (!_Py_atomic_load(&is_tripped)) return 0;
#ifdef WITH_THREAD Expand All @@ -1535,24 +1537,24 @@ PyErr_CheckSignals(void) * we receive a signal i after we zero is_tripped and before we * check Handlers[i].tripped. */ is_tripped = 0; _Py_atomic_store(&is_tripped, 0);
if (!(f = (PyObject *)PyEval_GetFrame())) f = Py_None;
for (i = 1; i < NSIG; i++) { if (Handlers[i].tripped) { if (_Py_atomic_load_relaxed(&Handlers[i].tripped)) { PyObject *result = NULL; PyObject *arglist = Py_BuildValue("(iO)", i, f); Handlers[i].tripped = 0; _Py_atomic_store_relaxed(&Handlers[i].tripped, 0);
if (arglist) { result = PyEval_CallObject(Handlers[i].func, arglist); Py_DECREF(arglist); } if (!result) { is_tripped = 1; _Py_atomic_store(&is_tripped, 1); return -1; }
Expand Down Expand Up @@ -1591,12 +1593,12 @@ PyOS_FiniInterrupts(void) int PyOS_InterruptOccurred(void) { if (Handlers[SIGINT].tripped) { if (_Py_atomic_load_relaxed(&Handlers[SIGINT].tripped)) { #ifdef WITH_THREAD if (PyThread_get_thread_ident() != main_thread) return 0; #endif Handlers[SIGINT].tripped = 0; _Py_atomic_store_relaxed(&Handlers[SIGINT].tripped, 0); return 1; } return 0; Expand All @@ -1606,11 +1608,11 @@ static void _clear_pending_signals(void) { int i; if (!is_tripped) if (!_Py_atomic_load(&is_tripped)) return; is_tripped = 0; _Py_atomic_store(&is_tripped, 0); for (i = 1; i < NSIG; ++i) { Handlers[i].tripped = 0; _Py_atomic_store_relaxed(&Handlers[i].tripped, 0); } }
Expand Down