trace-cmd: Have trace-cmd record -c set function-fork option if exists

Commit Message

Steven Rostedt March 2, 2020, 6:03 p.m. UTC

From: "Steven Rostedt (VMware)" <[e-mail]>

If the function-fork option exists on the machine, then it should be set if
'-c' is added to trace-cmd record. Othrewise the function tracers will not
trace the children of the process it is recording.

Signed-off-by: Steven Rostedt (VMware) <[e-mail]>
---
 tracecmd/trace-record.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

Patch

diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c
index 0a3851ad..2866b776 100644
--- a/tracecmd/trace-record.c
+++ b/tracecmd/trace-record.c
@@ -128,6 +128,7 @@  static int len_filter_pids;
 
 static int have_set_event_pid;
 static int have_event_fork;
+static int have_func_fork;
 
 struct opt_list {
 	struct opt_list *next;
@@ -354,6 +355,14 @@  static void test_set_event_pid(void)
 	}
 	tracefs_put_tracing_file(path);
 
+	path = tracefs_get_tracing_file("options/function-fork");
+	ret = stat(path, &st);
+	if (!ret) {
+		have_func_fork = 1;
+		reset_save_file(path, RESET_DEFAULT_PRIO);
+	}
+	tracefs_put_tracing_file(path);
+
 	tested = 1;
 }
 
@@ -5595,6 +5604,8 @@  static void parse_record_options(int argc,
 				save_option("event-fork");
 				ctx->do_child = 1;
 			}
+			if (have_func_fork)
+				save_option("function-fork");
 			break;
 		case 'C':
 			ctx->instance->clock = optarg;