On 2017/02/25 02:12AM, Masami Hiramatsu wrote:
> On Thu, 23 Feb 2017 17:07:24 +0530
> "Naveen N. Rao" <naveen.n....@linux.vnet.ibm.com> wrote:
>
> > We indicate support for accepting sym+offset with kretprobes through a
> > line in ftrace README. Parse the same to identify support and choose the
> > appropriate format for kprobe_events.
> >
> > Signed-off-by: Naveen N. Rao <naveen.n....@linux.vnet.ibm.com>
> > ---
> > tools/perf/util/probe-event.c | 49
> > ++++++++++++++++++++++++++++++++++++-------
> > tools/perf/util/probe-event.h | 2 ++
> > 2 files changed, 44 insertions(+), 7 deletions(-)
> >
> > diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
> > index 35f5b7b7715c..dd6b9ce0eef3 100644
> > --- a/tools/perf/util/probe-event.c
> > +++ b/tools/perf/util/probe-event.c
> > @@ -737,6 +737,43 @@ post_process_module_probe_trace_events(struct
> > probe_trace_event *tevs,
> > return ret;
> > }
> >
> > +bool is_kretprobe_offset_supported(void)
> > +{
> > + FILE *fp;
> > + char *buf = NULL;
> > + size_t len = 0;
> > + bool target_line = false;
> > + static int supported = -1;
> > + int fd;
> > +
> > + if (supported >= 0)
> > + return !!supported;
> > +
> > + fd = open_trace_file("README", false);
> > + if (fd < 0)
> > + return false;
> > +
> > + fp = fdopen(fd, "r");
> > + if (!fp) {
> > + close(fd);
> > + return false;
> > + }
> > +
> > + while (getline(&buf, &len, fp) > 0) {
> > + target_line = !!strstr(buf, "place (kretprobe): ");
> > + if (!target_line)
> > + continue;
> > + supported = 1;
> > + }
> > + if (supported == -1)
> > + supported = 0;
> > +
> > + fclose(fp);
> > + free(buf);
> > +
> > + return !!supported;
> > +}
>
> Hmm, I think you can do more than that.
> Can you reuse probe_type_is_available() to scan README?
> I think we can have something like scan_ftrace_readme() in probe-file.c
> to scan all the options and cache the results.
>
> probe_type_is_available() and kreprobe_offset_is_available()
> just returns cached result or scan it in first call.(I would like to
> ask you to do it in probe-file.c too)
Ok sure, that makes sense. I see that we only ever care about support
for hex type, so I will add a separate routine to only look for that and
the newly added kretprobe offset support.
- Naveen
