On 20 May 2014 08:51, Qu Wenruo <quwenruo@xxxxxxxxxxxxxx> wrote:
> When using parse_size(), even non-numeric value is passed, it will only
> give error message "ERROR: size value is empty", which is quite
> confusing for end users.
>
> This patch will introduce more meaningful error message for the
> following new cases
> 1) Invalid size string (non-numeric string)
> 2) Minus size value (like "-1K")
>
> Also this patch will take full use of endptr returned by strtoll() to
> reduce unneeded loop.
>
> Reported-by: Hidetoshi Seto <seto.hidetoshi@xxxxxxxxxxxxxx>
> Signed-off-by: Qu Wenruo <quwenruo@xxxxxxxxxxxxxx>
> ---
> utils.c | 53 +++++++++++++++++++++++++++++++++--------------------
> 1 file changed, 33 insertions(+), 20 deletions(-)
>
> diff --git a/utils.c b/utils.c
> index 392c5cf..1cbe102 100644
> --- a/utils.c
> +++ b/utils.c
> @@ -1612,18 +1612,20 @@ scan_again:
>
> u64 parse_size(char *s)
> {
> - int i;
> char c;
> u64 mult = 1;
> -
> - for (i = 0; s && s[i] && isdigit(s[i]); i++) ;
> - if (!i) {
> - fprintf(stderr, "ERROR: size value is empty\n");
> - exit(50);
> - }
> -
> - if (s[i]) {
> - c = tolower(s[i]);
> + long long int ret = 0;
> + char *endptr;
> +
> + if (!s)
> + goto empty;
> + ret = strtoll(s, &endptr, 10);
> + if (endptr == s)
> + goto invalid;
> + if (endptr[0] && endptr[1])
> + goto suffix;
> + if (endptr[0]) {
> + c = tolower(endptr[0]);
> switch (c) {
> case 'e':
> mult *= 1024;
> @@ -1646,18 +1648,29 @@ u64 parse_size(char *s)
> case 'b':
> break;
> default:
> - fprintf(stderr, "ERROR: Unknown size descriptor "
> - "'%c'\n", c);
> - exit(1);
> + goto descriptor;
> }
> }
> - if (s[i] && s[i+1]) {
> - fprintf(stderr, "ERROR: Illegal suffix contains "
> - "character '%c' in wrong position\n",
> - s[i+1]);
> - exit(51);
> - }
> - return strtoull(s, NULL, 10) * mult;
> + ret *= mult;
> + if (ret <= 0)
> + goto minus;
> + return (u64) ret;
> +empty:
> + fprintf(stderr, "ERROR: Size value is empty\n");
> + exit(50);
> +suffix:
> + fprintf(stderr, "ERROR: Illegal suffix contains character '%c' in wrong position\n",
> + endptr[1]);
> + exit(51);
> +descriptor:
> + fprintf(stderr, "ERROR: Unknown size descriptor '%c'\n", c);
> + exit(52);
> +invalid:
> + fprintf(stderr, "ERROR: Size value '%s' is invalid\n", s);
> + exit(53);
> +minus:
> + fprintf(stderr, "ERROR: Size value '%s' is less equal than 0\n", s);
> + exit(54);
> }
>
> int open_file_or_dir3(const char *fname, DIR **dirstream, int open_flags)
> --
> 1.9.2
>
IMHO use of this "if condition goto print error exit" pattern makes
the code harder to read. Use of gotos is used when a function creates
state which needs tearing down in reverse on error before returning.
I think the errors should be printed at the point of detection. Like
this:
+ if (!s) {
+ fprintf(stderr, "ERROR: Size value is empty\n");
+ exit(1);
+ }
+ ret = strtoll(s, &endptr, 10);
+ if (endptr == s) {
+ fprintf(stderr, "ERROR: Size value '%s' is invalid\n", s);
+ exit(1);
+ }
etc.
Thanks,
Mike
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