[PATCH 1/2] trace-cruncher: More options for stopping data iteration

[PATCH 1/2] trace-cruncher: More options for stopping data iteration

[Yordan Karadzhov (VMware)]

So far the only option to stop the iteration over the tracing data
from the callback function was to call 'sys.exit()'. However, this
only stops the iteration without actually exiting. With this change
calling 'sys.exit()' will terminate (exit the module), while in
order to just stop the iteration, the callback should return nonzero
integer value.

Signed-off-by: Yordan Karadzhov (VMware) <y.karadz@gmail.com>
---
 src/ftracepy-utils.c | 27 +++++++++++++++++++++------
 1 file changed, 21 insertions(+), 6 deletions(-)

diff --git a/src/ftracepy-utils.c b/src/ftracepy-utils.c
index d25d873..8e803ee 100644
--- a/src/ftracepy-utils.c
+++ b/src/ftracepy-utils.c
@@ -2046,21 +2046,36 @@ static int callback(struct tep_event *event, struct tep_record *record,
 	ret = PyObject_CallObject((PyObject *)ctx->py_callback, arglist);
 	Py_DECREF(arglist);
 
-	if (ret) {
-		Py_DECREF(ret);
-	} else {
+	if (!ret) {
 		if (PyErr_Occurred()) {
-			if (PyErr_ExceptionMatches(PyExc_SystemExit)) {
-				PyErr_Clear();
+			PyObject *err_type, *err_value, *err_traceback;
+
+			PyErr_Fetch(&err_type, &err_value, &err_traceback);
+			if (err_type == PyExc_SystemExit) {
+				if (PyLong_CheckExact(err_value))
+					Py_Exit(PyLong_AsLong(err_value));
+				else
+					Py_Exit(0);
 			} else {
+				PyErr_Restore(err_type, err_value, err_traceback);
 				PyErr_Print();
 			}
 		}
 
-		ctx->status = false;
+		goto stop;
+	}
+
+	if (PyLong_CheckExact(ret) && PyLong_AsLong(ret) != 0) {
+		Py_DECREF(ret);
+		goto stop;
 	}
 
+	Py_DECREF(ret);
 	return 0;
+
+ stop:
+	ctx->status = false;
+	return 1;
 }
 
 static bool notrace_this_pid(struct tracefs_instance *instance)
-- 
2.32.0

[PATCH 2/2] trace-cruncher: Make the tracing of a process stoppable

[Yordan Karadzhov (VMware)]

Both 'trace_process()' and 'trace_shell_process()' can be stopped
from the callback function by calling 'sys.exit()' or by returning
non zero integer value.

Signed-off-by: Yordan Karadzhov (VMware) <y.karadz@gmail.com>
---
 src/ftracepy-utils.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/src/ftracepy-utils.c b/src/ftracepy-utils.c
index 8e803ee..b5cdcee 100644
--- a/src/ftracepy-utils.c
+++ b/src/ftracepy-utils.c
@@ -2097,10 +2097,17 @@ static void iterate_raw_events_waitpid(struct tracefs_instance *instance,
 				       PyObject *py_func,
 				       pid_t pid)
 {
+	bool *callback_status = &callback_ctx.status;
+	int ret;
+
 	callback_ctx.py_callback = py_func;
+	(*(volatile bool *)callback_status) = true;
 	do {
-		tracefs_iterate_raw_events(tep, instance, NULL, 0,
-					   callback, &callback_ctx);
+		ret = tracefs_iterate_raw_events(tep, instance, NULL, 0,
+						 callback, &callback_ctx);
+
+		if (*(volatile bool *)callback_status == false || ret < 0)
+			break;
 	} while (waitpid(pid, NULL, WNOHANG) != pid);
 }
 
-- 
2.32.0