Re: [PATCH -tip 2/4] [BUGFIX]perf: Fix strlist__parse_list to handle const string

[Arnaldo Carvalho de Melo <acme@infradead.org>]

Em Fri, Dec 17, 2010 at 10:12:06PM +0900, Masami Hiramatsu escreveu:
> Fix strlist__parse_list to handle const string. Without this patch,
> strlist__parse_list() causes SEGV when caller passes a constant
> string.
 
> +++ b/tools/perf/util/strlist.c
> @@ -136,13 +136,19 @@ static int strlist__parse_list_entry(struct strlist *self, const char *s)
>  
>  int strlist__parse_list(struct strlist *self, const char *s)
>  {
> -	char *sep;
> +	char *sep, *tmp;
>  	int err;
>  
> +	/* This method requires strdup, because this changes given string */
> +	if (!self->dupstr)
> +		return -EINVAL;
> +

Why is the above check needed if you solved the problem by strnduping at
each separator?

Wouldn't be better to just stop changing the string by passing the
length to strlist__parse_list_entry, etc?

>  	while ((sep = strchr(s, ',')) != NULL) {
> -		*sep = '\0';
> -		err = strlist__parse_list_entry(self, s);
> -		*sep = ',';
> +		tmp = strndup(s, sep - s);
> +		if (tmp == NULL)
> +			return -ENOMEM;
> +		err = strlist__parse_list_entry(self, tmp);
> +		free(tmp);
>  		if (err != 0)
>  			return err;
>  		s = sep + 1;