Re: [PATCH 13/15] perf script python: Fix string vs byte array resolving

From: Steven Rostedt
Date: Thu Jul 28 2016 - 14:42:25 EST


On Mon, 18 Jul 2016 20:33:16 -0300
Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> wrote:

> From: Jiri Olsa <jolsa@xxxxxxxxxx>
>
> Jirka reported that python code returns all arrays as strings. This
> makes impossible to get all items for byte array tracepoint field
> containing 0x00 value item.
>
> Fixing this by scanning full length of the array and returning it as
> PyByteArray object in case non printable byte is found.
>
> Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
> Reported-and-Tested-by: Jiri Pirko <jiri@xxxxxxxxxxxx>
> Cc: David Ahern <dsahern@xxxxxxxxx>
> Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
> Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
> Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
> Link: http://lkml.kernel.org/r/1468685480-18951-2-git-send-email-jolsa@xxxxxxxxxx
> Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> ---
> .../util/scripting-engines/trace-event-python.c | 39 ++++++++++++++++++----
> 1 file changed, 33 insertions(+), 6 deletions(-)
>
> diff --git a/tools/perf/util/scripting-engines/trace-event-python.c b/tools/perf/util/scripting-engines/trace-event-python.c
> index 6ac6b7a33f42..7bd6da80533e 100644
> --- a/tools/perf/util/scripting-engines/trace-event-python.c
> +++ b/tools/perf/util/scripting-engines/trace-event-python.c
> @@ -386,6 +386,21 @@ exit:
> return pylist;
> }
>
> +static int is_printable_array(char *p, unsigned int len)
> +{
> + unsigned int i;
> +
> + if (!p || !len || p[len - 1] != 0)
> + return 0;
> +
> + len--;
> +
> + for (i = 0; i < len; i++) {
> + if (!isprint(p[i]) && !isspace(p[i]))
> + return 0;
> + }
> + return 1;
> +}
>

Darn, I never got to add my Reviewed-by tag, as I had lots of comments
on this function. Oh well, that's what happens when you go off to
volcanoes.

-- Steve