Re: [PATCH 10/10] perf script python: Fix string vs byte array resolving

From: Arnaldo Carvalho de Melo
Date: Tue Jul 12 2016 - 15:27:26 EST


Em Tue, Jul 12, 2016 at 09:48:36AM -0400, Steven Rostedt escreveu:
> On Tue, 12 Jul 2016 15:35:52 +0200
> Jiri Olsa <jolsa@xxxxxxxxxx> wrote:
>
> > On Tue, Jul 12, 2016 at 09:00:01AM -0400, Steven Rostedt wrote:
> > > On Tue, 12 Jul 2016 14:52:45 +0200
> > > Jiri Olsa <jolsa@xxxxxxxxxx> wrote:
> > >
> > >
> > > > hum, so string is not passed to trace buffer with 0 at the end?
> > >
> > > strlen() returns only the length of the string (minus the \0 at the
> > > end).
> >
> > yea, is_printable_array is called here on tracepoint
> > data that's why I asked.. is 0 part of the string data
> > when stored within tracepoint?
>
> Good question. It may or may not (haven't looked at the code), but we
> probably want to make sure that the function is robust enough for
> either case.

Ok, applied and tested up to patch 9, waiting for this discussion to
come to an end to consider 10.

- Arnaldo

> >
> > >
> > > >
> > > > I'll check the option of passing everything as PyByteArray.
> > > > If it's the same for user, we'll have simpler code in here.
> > > >
> > > > >
> > > > > because the last byte wont be 0. What about:
> > > > >
> > > > > for (i = 0; i < len; i++)
> > > > > if (!isprint(p[i]) && !isspace(p[i]))
> > > > > break;
> > > > >
> > > > > return i == len ||
> > > > > (i == len - 1 && p[i] == 0);
> > >
> > > Or you can do:
> > >
> > > if (p[len - 1] == 0)
> > > len--;
> > >
> > > for (i = 0; i < len; i++)
> > > if (!isprint(p[i]) && !isspace(p[i]))
> > > return 0;
> > > return 1;
> >
> > yep, seems good.. thanks
> >
>
> OK, great!
>
> -- Steve