[alsa-devel] [PATCH v2 6/7] topology: Add support for parsing vendor tuples

[Mengdong Lin]

On 04/05/2016 02:14 PM, Takashi Iwai wrote:
> On Tue, 05 Apr 2016 07:47:08 +0200,
> Mengdong Lin wrote:
>>
>>
>>
>> On 03/30/2016 03:35 PM, Takashi Iwai wrote:
>>> On Wed, 30 Mar 2016 09:11:17 +0200,
>>> mengdong.lin at linux.intel.com wrote:
>>>>
>>>> +		switch (type) {
>>>> +		case SND_SOC_TPLG_TUPLE_TYPE_UUID:
>>>> +			len = strlen(value);
>>>> +			if (len > 16 || len == 0) {
>>>> +				SNDERR("error: tuple %s: invalid uuid\n", id);
>>>> +				goto err;
>>>> +			}
>>>> +
>>>> +			memcpy(tuple->uuid, value, 16);
>>>
>>> This may still overflow :)
>>> How about simply using elem_copy_text()?
>>
>> Sorry for the late reply.
>>
>> Would you mind me using uuid_parse() here?
>> It can convert an input UUID string into the binary representation.
>>
>> An UUID string link "1b4e28ba-2fa1-11d2-883f-b9a761bde3fb" is user
>> friendly for the text conf file. But this will add dependency on libuuid.
>
> Additional dependency is no-go, especially when the required change is
> so trivial.  It's just a string copy, after all.
>

Maybe we can just use strncpy(dest, src, 16), assuming the strncpy will 
not try to write a "\0" at dest[16] that may cause overflow?

The user need to define uuid without "-" in the UUID string in the text 
conf file.

Now the uuid value in ABI is 16-character array:

/* vendor tuple for uuid */
struct snd_soc_tplg_vendor_uuid_elem {
	__le32 token;
	char uuid[16];
} __attribute__((packed));

The last byte of UUID may not be zero.

Thanks
Mengdong