On 2/21/14, 12:07 AM, Wang Shilong wrote:
> There are many places that need parse string to u64 for btrfs commands,
> in fact, we do such things *too casually*, using atoi/atol/atoll..is not
> right at all, and even we don't check whether it is a valid string.
>
> Let's do everything more gracefully, we introduce a new helper
> arg_strtou64() which will do all the necessary checks.If we fail to
> parse string to u64, we will output message and exit directly, this is
> something like what usage() is doing. It is ok to not return erro to
> it's caller, because this function should be called when parsing arg
> (just like usage!)
>
> Signed-off-by: Wang Shilong <wangsl.fnst@xxxxxxxxxxxxxx>
I like it, thanks.
Reviewed-by: Eric Sandeen <sandeen@xxxxxxxxxx>
> ---
> v3->v4:
> move prefix '-' check after strtoull call, which will
> make negative output more precise to common users!(Thanks to Eric Sandeen)
> ---
> utils.c | 33 +++++++++++++++++++++++++++++++++
> utils.h | 1 +
> 2 files changed, 34 insertions(+)
>
> diff --git a/utils.c b/utils.c
> index 97e23d5..9120877 100644
> --- a/utils.c
> +++ b/utils.c
> @@ -1520,6 +1520,39 @@ scan_again:
> return 0;
> }
>
> +/*
> + * This function should be only used when parsing
> + * command arg, it won't return error to it's
> + * caller and rather exit directly just like usage().
> + */
> +u64 arg_strtou64(const char *str)
> +{
> + u64 value;
> + char *ptr_parse_end = NULL;
> +
> + value = strtoull(str, &ptr_parse_end, 0);
> + if (ptr_parse_end && *ptr_parse_end != '\0') {
> + fprintf(stderr, "ERROR: %s is not a valid numeric value.\n",
> + str);
> + exit(1);
> + }
> + /*
> + * if we pass a negative number to strtoull,
> + * it will return an unexpected number to us,
> + * so let's do the check ourselves.
> + */
> + if (str[0] == '-') {
> + fprintf(stderr, "ERROR: %s: negative value is invalid.\n",
> + str);
> + exit(1);
> + }
> + if (value == ULLONG_MAX) {
> + fprintf(stderr, "ERROR: %s is too large.\n", str);
> + exit(1);
> + }
> + return value;
> +}
> +
> u64 parse_size(char *s)
> {
> int i;
> diff --git a/utils.h b/utils.h
> index 04b8c45..a201085 100644
> --- a/utils.h
> +++ b/utils.h
> @@ -71,6 +71,7 @@ int pretty_size_snprintf(u64 size, char *str, size_t str_bytes);
> int get_mountpt(char *dev, char *mntpt, size_t size);
> int btrfs_scan_block_devices(int run_ioctl);
> u64 parse_size(char *s);
> +u64 arg_strtou64(const char *str);
> int open_file_or_dir(const char *fname, DIR **dirstream);
> void close_file_or_dir(int fd, DIR *dirstream);
> int get_fs_info(char *path, struct btrfs_ioctl_fs_info_args *fi_args,
>
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