Re: [PATCH V2 4/9 linux-next] udf: improve error management in udf_CS0toUTF8()

[Jan Kara <jack@suse.cz>]

On Wed 08-04-15 21:23:54, Fabian Frederick wrote:
> udf_CS0toUTF8() now returns -EINVAL on error.
> udf_load_pvoldesc() and udf_get_filename() do the same.
> 
> Suggested-by: Jan Kara <jack@suse.cz>
> Signed-off-by: Fabian Frederick <fabf@skynet.be>
  After some thought it's probably better API that udf_CS0toUTF8() simply
returns 0 when 0-lenght string is provided as an input (there's nothing
invalid in that from the point of view of that conversion functions). We
cannot actually ever call udf_CS0toUTF8() with such string currently but I
think it's better for future. So I've changed this and merged the patch.

								Honza
> ---
>  fs/udf/super.c   | 23 ++++++++++++++---------
>  fs/udf/unicode.c |  9 +++++----
>  2 files changed, 19 insertions(+), 13 deletions(-)
> 
> diff --git a/fs/udf/super.c b/fs/udf/super.c
> index 6299f34..c6a8f5f 100644
> --- a/fs/udf/super.c
> +++ b/fs/udf/super.c
> @@ -927,17 +927,22 @@ static int udf_load_pvoldesc(struct super_block *sb, sector_t block)
>  #endif
>  	}
>  
> -	if (!udf_build_ustr(instr, pvoldesc->volIdent, 32))
> -		if (udf_CS0toUTF8(outstr, instr)) {
> -			strncpy(UDF_SB(sb)->s_volume_ident, outstr->u_name,
> -				outstr->u_len > 31 ? 31 : outstr->u_len);
> -			udf_debug("volIdent[] = '%s'\n",
> -				  UDF_SB(sb)->s_volume_ident);
> -		}
> +	if (!udf_build_ustr(instr, pvoldesc->volIdent, 32)) {
> +		ret = udf_CS0toUTF8(outstr, instr);
> +		if (ret < 0)
> +			goto out_bh;
> +
> +		strncpy(UDF_SB(sb)->s_volume_ident, outstr->u_name,
> +			outstr->u_len > 31 ? 31 : outstr->u_len);
> +		udf_debug("volIdent[] = '%s'\n", UDF_SB(sb)->s_volume_ident);
> +	}
>  
>  	if (!udf_build_ustr(instr, pvoldesc->volSetIdent, 128))
> -		if (udf_CS0toUTF8(outstr, instr))
> -			udf_debug("volSetIdent[] = '%s'\n", outstr->u_name);
> +		ret = udf_CS0toUTF8(outstr, instr);
> +		if (ret < 0)
> +			goto out_bh;
> +
> +		udf_debug("volSetIdent[] = '%s'\n", outstr->u_name);
>  
>  	ret = 0;
>  out_bh:
> diff --git a/fs/udf/unicode.c b/fs/udf/unicode.c
> index 41c3bef..9008a36 100644
> --- a/fs/udf/unicode.c
> +++ b/fs/udf/unicode.c
> @@ -89,7 +89,7 @@ static void udf_build_ustr_exact(struct ustr *dest, dstring *ptr, int exactsize)
>   * 				both of type "struct ustr *"
>   *
>   * POST-CONDITIONS
> - *	<return>		Zero on success.
> + *	<return>		>= 0 on success.
>   *
>   * HISTORY
>   *	November 12, 1997 - Andrew E. Mileski
> @@ -104,7 +104,7 @@ int udf_CS0toUTF8(struct ustr *utf_o, const struct ustr *ocu_i)
>  	ocu_len = ocu_i->u_len;
>  	if (ocu_len == 0) {
>  		memset(utf_o, 0, sizeof(struct ustr));
> -		return 0;
> +		return -EINVAL;
>  	}
>  
>  	cmp_id = ocu_i->u_cmpID;
> @@ -112,7 +112,7 @@ int udf_CS0toUTF8(struct ustr *utf_o, const struct ustr *ocu_i)
>  		memset(utf_o, 0, sizeof(struct ustr));
>  		pr_err("unknown compression code (%d) stri=%s\n",
>  		       cmp_id, ocu_i->u_name);
> -		return 0;
> +		return -EINVAL;
>  	}
>  
>  	ocu = ocu_i->u_name;
> @@ -350,7 +350,8 @@ int udf_get_filename(struct super_block *sb, uint8_t *sname, int slen,
>  
>  	udf_build_ustr_exact(unifilename, sname, slen);
>  	if (UDF_QUERY_FLAG(sb, UDF_FLAG_UTF8)) {
> -		if (!udf_CS0toUTF8(filename, unifilename)) {
> +		ret = udf_CS0toUTF8(filename, unifilename);
> +		if (ret < 0) {
>  			udf_debug("Failed in udf_get_filename: sname = %s\n",
>  				  sname);
>  			goto out2;
> -- 
> 1.9.1
> 
-- 
Jan Kara <jack@suse.cz>
SUSE Labs, CR