Re: [PATCH 02/14] tools lib traceevent: Get rid of die in add_filter_type()

[Jiri Olsa <jolsa@redhat.com>]

On Mon, Dec 09, 2013 at 02:33:59PM +0900, Namhyung Kim wrote:
> The realloc() should check return value and not to overwrite previous
> pointer in case of error.
> 
> Signed-off-by: Namhyung Kim <namhyung@kernel.org>
> ---
>  tools/lib/traceevent/parse-filter.c | 21 ++++++++++++++++-----
>  1 file changed, 16 insertions(+), 5 deletions(-)
> 
> diff --git a/tools/lib/traceevent/parse-filter.c b/tools/lib/traceevent/parse-filter.c
> index 0fc905c230ad..d9c239933992 100644
> --- a/tools/lib/traceevent/parse-filter.c
> +++ b/tools/lib/traceevent/parse-filter.c
> @@ -161,11 +161,13 @@ add_filter_type(struct event_filter *filter, int id)
>  	if (filter_type)
>  		return filter_type;
>  
> -	filter->event_filters =	realloc(filter->event_filters,
> -					sizeof(*filter->event_filters) *
> -					(filter->filters + 1));
> -	if (!filter->event_filters)
> -		die("Could not allocate filter");
> +	filter_type = realloc(filter->event_filters,
> +			      sizeof(*filter->event_filters) *
> +			      (filter->filters + 1));
> +	if (!filter_type)
> +		return NULL;
> +
> +	filter->event_filters = filter_type;
>  
>  	for (i = 0; i < filter->filters; i++) {
>  		if (filter->event_filters[i].event_id > id)
> @@ -1164,6 +1166,12 @@ static int filter_event(struct event_filter *filter,
>  	}
>  
>  	filter_type = add_filter_type(filter, event->id);
> +	if (filter_type == NULL) {
> +		show_error(error_str, "failed to add a new filter: %s",
> +			   filter_str ? filter_str : "true");
> +		return -1;

so your key for using show_error in case of error is if it's
used already in the error path in the function.. right?

jirka

> +	}
> +
>  	if (filter_type->filter)
>  		free_arg(filter_type->filter);
>  	filter_type->filter = arg;
> @@ -1395,6 +1403,9 @@ static int copy_filter_type(struct event_filter *filter,
>  			arg->boolean.value = 0;
>  
>  		filter_type = add_filter_type(filter, event->id);
> +		if (filter_type == NULL)
> +			return -1;
> +
>  		filter_type->filter = arg;
>  
>  		free(str);
> -- 
> 1.7.11.7
>