On Mon, Nov 26, 2018 at 05:19:45PM -0500, Gabriel Krisman Bertazi wrote:
> +static int utf8_casefold(const struct nls_table *table,
> + const unsigned char *str, size_t len,
> + unsigned char *dest, size_t dlen)
> +{
> + const struct utf8data *data = utf8nfkdicf(UNICODE_AGE(10,0,0));
> + struct utf8cursor cur;
> + size_t nlen = 0;
> +
> + if (utf8ncursor(&cur, data, str, len) < 0)
> + goto invalid_seq;
> +
> + for (nlen = 0; nlen < dlen; nlen++) {
> + dest[nlen] = utf8byte(&cur);
> + if (!dest[nlen])
> + return nlen;
> + if (dest[nlen] == -1)
> + break;
> + }
> +invalid_seq:
> + /* Treat the sequence as a binary blob. */
> + memcpy(dest, str, len);
> + return len;
> +
> +}
So it looks like the interface is if the destination buffer is too
small OR if the string is not a valid UTF-8 string, we treat it as a
binary blob. I wonder if we would be better off if this function
actually signalling that there is a problem? (Buffer too small,
invalid UTF-8 string).
It's fine to treat it as a binary blob, and copy it out to the
destination buffer, but I can imagine be use cases where knowing this
will be useful. *Especially* the destination buffer too small case;
I'm actually a little nervous about having it silently ignoring that
error condition and just copying the binary blob.
Also, there *really* needs to be a check before dlen is assumed to be
>= len in the memcpy after the invalid_seq label.
- Ted
