GH-93503: Add thread-specific APIs to set profiling and tracing functions in the C-API (#93504)

* gh-93503: Add APIs to set profiling and tracing functions in all threads in the C-API

* Use a separate API

* Fix NEWS entry

* Add locks around the loop

* Document ignoring exceptions

* Use the new APIs in the sys module

* Update docs

Python/ceval.c

@@ -96,6 +96,10 @@
 #define _Py_atomic_load_relaxed_int32(ATOMIC_VAL) _Py_atomic_load_relaxed(ATOMIC_VAL)
 #endif
 
+#define HEAD_LOCK(runtime) \
+    PyThread_acquire_lock((runtime)->interpreters.mutex, WAIT_LOCK)
+#define HEAD_UNLOCK(runtime) \
+    PyThread_release_lock((runtime)->interpreters.mutex)
 
 /* Forward declarations */
 static PyObject *trace_call_function(
@@ -6455,6 +6459,27 @@ PyEval_SetProfile(Py_tracefunc func, PyObject *arg)
     }
 }
 
+void
+PyEval_SetProfileAllThreads(Py_tracefunc func, PyObject *arg)
+{
+    PyThreadState *this_tstate = _PyThreadState_GET();
+    PyInterpreterState* interp = this_tstate->interp;
+
+    _PyRuntimeState *runtime = &_PyRuntime;
+    HEAD_LOCK(runtime);
+    PyThreadState* ts = PyInterpreterState_ThreadHead(interp);
+    HEAD_UNLOCK(runtime);
+
+    while (ts) {
+        if (_PyEval_SetProfile(ts, func, arg) < 0) {
+            _PyErr_WriteUnraisableMsg("in PyEval_SetProfileAllThreads", NULL);
+        }
+        HEAD_LOCK(runtime);
+        ts = PyThreadState_Next(ts);
+        HEAD_UNLOCK(runtime);
+    }
+}
+
 int
 _PyEval_SetTrace(PyThreadState *tstate, Py_tracefunc func, PyObject *arg)
 {
@@ -6508,6 +6533,26 @@ PyEval_SetTrace(Py_tracefunc func, PyObject *arg)
     }
 }
 
+void
+PyEval_SetTraceAllThreads(Py_tracefunc func, PyObject *arg)
+{
+    PyThreadState *this_tstate = _PyThreadState_GET();
+    PyInterpreterState* interp = this_tstate->interp;
+
+    _PyRuntimeState *runtime = &_PyRuntime;
+    HEAD_LOCK(runtime);
+    PyThreadState* ts = PyInterpreterState_ThreadHead(interp);
+    HEAD_UNLOCK(runtime);
+
+    while (ts) {
+        if (_PyEval_SetTrace(ts, func, arg) < 0) {
+            _PyErr_WriteUnraisableMsg("in PyEval_SetTraceAllThreads", NULL);
+        }
+        HEAD_LOCK(runtime);
+        ts = PyThreadState_Next(ts);
+        HEAD_UNLOCK(runtime);
+    }
+}
 
 int
 _PyEval_SetCoroutineOriginTrackingDepth(int depth)

Python/clinic/sysmodule.c.h

@@ -292,6 +292,18 @@ exit:
     return return_value;
 }
 
+PyDoc_STRVAR(sys__settraceallthreads__doc__,
+"_settraceallthreads($module, arg, /)\n"
+"--\n"
+"\n"
+"Set the global debug tracing function in all running threads belonging to the current interpreter.\n"
+"\n"
+"It will be called on each function call. See the debugger chapter\n"
+"in the library manual.");
+
+#define SYS__SETTRACEALLTHREADS_METHODDEF    \
+    {"_settraceallthreads", (PyCFunction)sys__settraceallthreads, METH_O, sys__settraceallthreads__doc__},
+
 PyDoc_STRVAR(sys_gettrace__doc__,
 "gettrace($module, /)\n"
 "--\n"
@@ -312,6 +324,18 @@ sys_gettrace(PyObject *module, PyObject *Py_UNUSED(ignored))
     return sys_gettrace_impl(module);
 }
 
+PyDoc_STRVAR(sys__setprofileallthreads__doc__,
+"_setprofileallthreads($module, arg, /)\n"
+"--\n"
+"\n"
+"Set the profiling function in all running threads belonging to the current interpreter.\n"
+"\n"
+"It will be called on each function call and return.  See the profiler chapter\n"
+"in the library manual.");
+
+#define SYS__SETPROFILEALLTHREADS_METHODDEF    \
+    {"_setprofileallthreads", (PyCFunction)sys__setprofileallthreads, METH_O, sys__setprofileallthreads__doc__},
+
 PyDoc_STRVAR(sys_getprofile__doc__,
 "getprofile($module, /)\n"
 "--\n"
@@ -1170,4 +1194,4 @@ sys_getandroidapilevel(PyObject *module, PyObject *Py_UNUSED(ignored))
 #ifndef SYS_GETANDROIDAPILEVEL_METHODDEF
     #define SYS_GETANDROIDAPILEVEL_METHODDEF
 #endif /* !defined(SYS_GETANDROIDAPILEVEL_METHODDEF) */
-/*[clinic end generated code: output=38446a4c76e2f3b6 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=322fb0409e376ad4 input=a9049054013a1b77]*/

Python/sysmodule.c

@@ -1021,6 +1021,36 @@ Set the global debug tracing function.  It will be called on each\n\
 function call.  See the debugger chapter in the library manual."
 );
 
+/*[clinic input]
+sys._settraceallthreads
+
+    arg: object
+    /
+
+Set the global debug tracing function in all running threads belonging to the current interpreter.
+
+It will be called on each function call. See the debugger chapter
+in the library manual.
+[clinic start generated code]*/
+
+static PyObject *
+sys__settraceallthreads(PyObject *module, PyObject *arg)
+/*[clinic end generated code: output=161cca30207bf3ca input=5906aa1485a50289]*/
+{
+    PyObject* argument = NULL;
+    Py_tracefunc func = NULL;
+
+    if (arg != Py_None) {
+        func = trace_trampoline;
+        argument = arg;
+    }
+
+
+    PyEval_SetTraceAllThreads(func, argument);
+
+    Py_RETURN_NONE;
+}
+
 /*[clinic input]
 sys.gettrace
 
@@ -1066,6 +1096,35 @@ Set the profiling function.  It will be called on each function call\n\
 and return.  See the profiler chapter in the library manual."
 );
 
+/*[clinic input]
+sys._setprofileallthreads
+
+    arg: object
+    /
+
+Set the profiling function in all running threads belonging to the current interpreter.
+
+It will be called on each function call and return.  See the profiler chapter
+in the library manual.
+[clinic start generated code]*/
+
+static PyObject *
+sys__setprofileallthreads(PyObject *module, PyObject *arg)
+/*[clinic end generated code: output=2d61319e27b309fe input=d1a356d3f4f9060a]*/
+{
+    PyObject* argument = NULL;
+    Py_tracefunc func = NULL;
+
+    if (arg != Py_None) {
+        func = profile_trampoline;
+        argument = arg;
+    }
+
+    PyEval_SetProfileAllThreads(func, argument);
+
+    Py_RETURN_NONE;
+}
+
 /*[clinic input]
 sys.getprofile
 
@@ -2035,9 +2094,11 @@ static PyMethodDef sys_methods[] = {
     SYS_GETSWITCHINTERVAL_METHODDEF
     SYS_SETDLOPENFLAGS_METHODDEF
     {"setprofile", sys_setprofile, METH_O, setprofile_doc},
+    SYS__SETPROFILEALLTHREADS_METHODDEF
     SYS_GETPROFILE_METHODDEF
     SYS_SETRECURSIONLIMIT_METHODDEF
     {"settrace", sys_settrace, METH_O, settrace_doc},
+    SYS__SETTRACEALLTHREADS_METHODDEF
     SYS_GETTRACE_METHODDEF
     SYS_CALL_TRACING_METHODDEF
     SYS__DEBUGMALLOCSTATS_METHODDEF