trace-cmd: Reset ftrace pid on disable all

Reset the ftrace pid on disable all and also fix the reset of the
file to perform a O_TRUNC, otherwise it keeps the previous pids.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 2 insertions, 1 deletions

diff --git a/trace-cmd.c b/trace-cmd.c
index 968904f..1365a73 100644
--- a/trace-cmd.c
+++ b/trace-cmd.c
@@ -273,7 +273,7 @@ static void update_ftrace_pid(const char *pid)
         if (!path)
                 return;
 
-        fd = open(path, O_WRONLY);
+        fd = open(path, O_WRONLY | O_TRUNC);
         if (fd < 0)
                 return;
 
@@ -716,6 +716,7 @@ static void disable_all(void)
 
         set_plugin("nop");
         update_event("all", "0", 0, '0');
+        update_ftrace_pid("");
 
         clear_trace();
 }