On Thu, 21 Dec 2017 17:25:20 +0200
"Vladislav Valtchev (VMware)" <vladislav.valtc...@gmail.com> wrote:
> trace-cmd stat is a handy way for users to see what tracing is currently going
> on, but currently it does not say anything about the stack tracing. This patch
> makes the command to show a message when the stack tracer is ON.
>
> Signed-off-by: Vladislav Valtchev (VMware) <vladislav.valtc...@gmail.com>
> ---
> trace-cmd.h | 2 ++
> trace-stack.c | 6 ++++++
> trace-stat.c | 8 ++++++++
> 3 files changed, 16 insertions(+)
>
> diff --git a/trace-cmd.h b/trace-cmd.h
> index 6fd34d7..9704b2e 100644
> --- a/trace-cmd.h
> +++ b/trace-cmd.h
> @@ -358,6 +358,8 @@ void tracecmd_free_hooks(struct hook_list *hooks);
> /* --- Hack! --- */
> int tracecmd_blk_hack(struct tracecmd_input *handle);
>
> +/* --- Stack tracer functions --- */
> +int tracecmd_stack_tracer_status(int *status);
>
> /* --- Debugging --- */
> struct kbuffer *tracecmd_record_kbuf(struct tracecmd_input *handle,
> diff --git a/trace-stack.c b/trace-stack.c
> index d55d994..0028ecc 100644
> --- a/trace-stack.c
> +++ b/trace-stack.c
> @@ -107,6 +107,12 @@ static int read_proc(int *status)
> return 1; /* full success */
> }
>
> +/* Public wrapper of read_proc() */
> +int tracecmd_stack_tracer_status(int *status)
> +{
> + return read_proc(status);
> +}
> +
> /* NOTE: this implementation only accepts new_status in the range [0..9]. */
> static void change_stack_tracer_status(int new_status)
> {
> diff --git a/trace-stat.c b/trace-stat.c
> index fd16354..61dd41f 100644
> --- a/trace-stat.c
> +++ b/trace-stat.c
> @@ -894,6 +894,7 @@ void trace_stat (int argc, char **argv)
> struct buffer_instance *instance = &top_instance;
> int topt = 0;
> int c;
> + int stack_tracer_status;
Needs to be upside down x-mas tree. (can't you feel the season?) ;-)
Not to mention, it's an awfully verbose variable name. Just call it
"status".
>
> for (;;) {
> c = getopt(argc-1, argv+1, "tB:");
> @@ -928,5 +929,12 @@ void trace_stat (int argc, char **argv)
> stat_instance(instance);
> }
>
> + if (tracecmd_stack_tracer_status(&stack_tracer_status) >= 0) {
> + if (stack_tracer_status > 0)
> + printf("Stack tracing is enabled\n\n");
> + } else {
> + printf("The status of the stack tracer is indeterminate\n\n");
I wonder if we should report saying there was an error?
printf("Error reading stack tracer status\n");
-- Steve
> + }
> +
> exit(0);
> }
