On Wed, 2013-03-20 at 10:12 +0900, Namhyung Kim wrote:
> >> +++ b/tools/perf/util/trace-event-read.c
> >> @@ -293,7 +293,10 @@ ssize_t trace_report(int fd, struct pevent **ppevent,
> >> bool __repipe)
> >> int show_version = 0;
> >> int show_funcs = 0;
> >> int show_printk = 0;
> >> - ssize_t size;
> >> + ssize_t size = -1;
> >> + struct pevent *pevent;
> >> +
> >> + *ppevent = NULL;
> >>
> >> calc_data_size = 1;
> >> repipe = __repipe;
> >> @@ -317,34 +320,38 @@ ssize_t trace_report(int fd, struct pevent
> >> **ppevent, bool __repipe)
> >> file_bigendian = buf[0];
> >> host_bigendian = bigendian();
> >>
> >> - *ppevent = read_trace_init(file_bigendian, host_bigendian);
> >> - if (*ppevent == NULL)
> >> - die("read_trace_init failed");
> >> + pevent = read_trace_init(file_bigendian, host_bigendian);
> >> + if (pevent == NULL) {
> >
> > Shouldn't we still set *ppevent to NULL? Or will the user now need to
> > make sure that its pevent is NULL and always check for error?
>
> I thought it's impossible to check return value for error since we don't
> know how large a tracing data is, so I decided to init *ppevent to NULL
> at the beginning and set it to a valid pevent right before return. Thus
> user need to check NULL before using it.
>
> In the above case of perf_event__process_tracing_data(), it's a pipe
> mode and we can know its size since it's saved in a temp file.
>
My fault, I missed the addition of *ppevent = NULL at the beginning.
Ignore this comment.
-- Steve
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