Re: [PATCH 1/3] cifs: Introduce helper to compute length of nls string in bytes

Am Dienstag, 21. April 2009 schrieb Suresh Jayaraman:
> Though the consensus is that we need a generalised helper to handle
> unicode string buffers so that other filesystems could consume, we would
> need a cifs helper like this in the interim, given the number of
> discussions/reviews and bug reports. cifs could easily replace this with
> generic helpers once such helper is in place.
> 
> 
> Signed-off-by: Suresh Jayaraman <[email protected]>
> ---
>  fs/cifs/cifs_unicode.h |   27 +++++++++++++++++++++++++++
>  1 files changed, 27 insertions(+), 0 deletions(-)
> 
> diff --git a/fs/cifs/cifs_unicode.h b/fs/cifs/cifs_unicode.h
> index 14eb9a2..8ab332b 100644
> --- a/fs/cifs/cifs_unicode.h
> +++ b/fs/cifs/cifs_unicode.h
> @@ -159,6 +159,33 @@ UniStrnlen(const wchar_t *ucs1, int maxlen)
>  }
>  
>  /*
> + * UniStrnlenBytes: Return the length of a NLS string in bytes. Also, populates
> + * 'nchars' with the length of string in 16 bit Unicode chars.
> + */
> +static inline size_t
> +UniStrnlenBytes(const wchar_t *str, int maxlen, int *nchars,
> +		const struct nls_table *codepage)
> +{
> +	int nc;
> +	size_t nbytes = 0;
> +	char buf[NLS_MAX_CHARSET_SIZE]; /* enough for one char at a time */
> +
> +	*nchars = 0;
> +	while (*str++ && maxlen) {
> +		nc = codepage->uni2char(*str, buf, NLS_MAX_CHARSET_SIZE);
> +		if (nc > 0)
> +			nbytes += nc;
> +		else
> +			nbytes += 1; /* for '?' */
> +		(*nchars)++;
> +		if (*nchars >= maxlen)
> +			break;
> +	}
> +
> +	return nbytes;
> +}
> +
> +/*
>   * UniStrncat:  Concatenate length limited string
>   */
>  static inline wchar_t *

during cleanup of the unicode related stuff we should also have a look
at functions currently located in misc.c
  - cifs_convertUCSpath()
  - cifsConvertToUCS()

At the moment cifs_convertUCSpath() contains the following check:
...
		/* make sure we do not overrun callers allocated temp buffer */
		if (j >= (2 * NAME_MAX))
			break;
...
Probably both functions should be moved away from misc.c.
Cheers, Günter