[PATCH v2] trace-cmd: Clear synthetic events on reset subcommand

["Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com>]

The "trace-cmd reset" command is supposed to set the ftrace state to default.
However, the synthetic events are not reseted.
A logic is added to delete all entries from "synthetic_events" files.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>

---
v2: remove the warning in case there are no configured synthetic events
---
 tracecmd/trace-record.c | 36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c
index 4a49b640..881efe44 100644
--- a/tracecmd/trace-record.c
+++ b/tracecmd/trace-record.c
@@ -4638,6 +4638,41 @@ static void clear_triggers(void)
 		clear_instance_triggers(instance);
 }
 
+static void clear_all_synth_events(void)
+{
+	char sevent[BUFSIZ];
+	char *save = NULL;
+	char *line;
+	char *file;
+	char *buf;
+	int len;
+
+	file = tracefs_instance_get_file(NULL, "synthetic_events");
+	if (!file)
+		return;
+
+	buf = read_file(file);
+	if (!buf)
+		goto out;
+
+	sevent[0] = '!';
+
+	for (line = strtok_r(buf, "\n", &save); line; line = strtok_r(NULL, "\n", &save)) {
+		len = strlen(line);
+		if (len > BUFSIZ - 2)
+			len = BUFSIZ - 2;
+		strncpy(sevent + 1, line, len);
+		sevent[len + 1] = '\0';
+		write_file(file, sevent);
+	}
+out:
+	free(buf);
+	tracefs_put_tracing_file(file);
+
+}
+
+
+
 static void clear_func_filters(void)
 {
 	struct buffer_instance *instance;
@@ -5344,6 +5379,7 @@ void trace_reset(int argc, char **argv)
 	set_buffer_size();
 	clear_filters();
 	clear_triggers();
+	clear_all_synth_events();
 	/* set clock to "local" */
 	reset_clock();
 	reset_event_pid();
-- 
2.24.1