Messages in this thread | | | Date | Tue, 17 Dec 2013 17:02:39 -0300 | From | Arnaldo Carvalho de Melo <> | Subject | Re: [PATCH 13/14] tools lib traceevent: Get rid of die() in some string conversion funcitons |
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Em Tue, Dec 17, 2013 at 09:02:36AM +0900, Namhyung Kim escreveu: > On Mon, 16 Dec 2013 09:40:51 -0300, Arnaldo Carvalho de Melo wrote: > > Em Mon, Dec 16, 2013 at 01:49:11PM +0900, Namhyung Kim escreveu: > >> On Fri, 13 Dec 2013 11:52:04 -0300, Arnaldo Carvalho de Melo wrote: > >> > All the rest is ok, so its just the malloc + strcpy that remains to be > >> > converted, do you want me to do it?
> >> Hmm.. did you mean like this?
> >> str = NULL; > >> if (val) > >> asprintf(&str, "TRUE"); > >> else > >> asprintf(&str, "FALSE"); > >> return str;
> > More compact:
> > if (asprintf(&str, "%s", val ? "TRUE" : "FALSE") < 0) > > // error handling path
> > At that point str already is set to NULL.
> Okay, this is a new one:
Thanks, it all seems now, but just prior to applying this I noticed:
> Those functions are for stringify filter arguments. As caller of > those functions handles NULL string properly, it seems that it's > enough to return NULL rather than calling die().
It handles NULL in what way? This comment:
> @@ -2369,7 +2340,7 @@ static char *arg_to_str(struct event_filter *filter, struct filter_arg *arg) > * Returns a string that displays the filter contents. > * This string must be freed with free(str). > - * NULL is returned if no filter is found. > + * NULL is returned if no filter is found or allocation failed. > */ > char * > pevent_filter_make_string(struct event_filter *filter, int event_id)
Made me a bit unconfortable, so if it handles NULL as a filter not found, how will it figure out what happened?
/me looks at the callers...
From just a quick look I couldn't see cases where NULL could cause segfaults, but saw some cases where allocation errors would not be notified in any way to the user :-\
Anyway, applying this patch, those are other kinds of problems, i.e. further fallout from converting from the previous panic()-at-alloc-failure approach.
- Arnaldo
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