On 10/09/2019 15.07, Takashi Iwai wrote:
> On Fri, 06 Sep 2019 07:55:24 +0200,
> Peter Ujfalusi wrote:
>>
>> Some tools use the snd_pcm_info_get_name() to try to identify PCMs or for
>> other purposes.
>>
>> Currently it is left empty with the dmaengine-pcm, in this case copy the
>> pcm->id string as pcm->name.
>>
>> For example IGT is using this to find the HDMI PCM for testing audio on it.
>>
>> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@xxxxxx>
>> Reported-by: Arthur She <arthur.she@xxxxxxxxxx>
>> ---
>> Hi,
>>
>> this was actually reported for 4.14 kernel with omap-pcm (replaced by sdma-pcm
>> in v4.18), since then we only use the generic dmaengine PCM but the same issue
>> applies today.
>>
>> Regards,
>> Peter
>>
>> sound/soc/soc-generic-dmaengine-pcm.c | 6 ++++++
>> 1 file changed, 6 insertions(+)
>>
>> diff --git a/sound/soc/soc-generic-dmaengine-pcm.c b/sound/soc/soc-generic-dmaengine-pcm.c
>> index 748f5f641002..d93db2c2b527 100644
>> --- a/sound/soc/soc-generic-dmaengine-pcm.c
>> +++ b/sound/soc/soc-generic-dmaengine-pcm.c
>> @@ -306,6 +306,12 @@ static int dmaengine_pcm_new(struct snd_soc_pcm_runtime *rtd)
>>
>> if (!dmaengine_pcm_can_report_residue(dev, pcm->chan[i]))
>> pcm->flags |= SND_DMAENGINE_PCM_FLAG_NO_RESIDUE;
>> +
>> + if (rtd->pcm->streams[i].pcm->name[0] == '\0') {
>> + strncpy(rtd->pcm->streams[i].pcm->name,
>> + rtd->pcm->streams[i].pcm->id,
>> + sizeof(rtd->pcm->streams[i].pcm->name));
>> + }
>
> Any reason to use strncpy() instead of strscpy()?
> After merging Mark's branch, I got a compile warning like:
> sound/soc/soc-generic-dmaengine-pcm.c:311:4: warning: 'strncpy'
> accessing 80 bytes at offsets 88 and 24 may overlap up to 0 bytes at
> offset [9223372036854775807, -9223372036854775808] [-Wrestrict]
I have not seen such a warning.
'may overlap up to 0 bytes' ?
snd_pcm_info {
...
unsigned char id[64]; /* ID (user selectable) */
unsigned char name[80]; /* name of this device */
unsigned char subname[32]; /* subdevice name */
...
};
and strncpy() supposed to be something like this:
char * strncpy(char *dest, const char *src, size_t n)
{
size_t i;
for (i = 0; i < n && src[i] != '\0'; i++)
dest[i] = src[i];
for ( ; i < n; i++)
dest[i] = '\0';
return dest;
}
I can see if I can get my compilers to show the warning and try
strscpy() if it helps on it.
>
>
> Takashi
>
>>
>> return 0;
>> --
>> Peter
>>
>> Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
>> Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
>>
>> _______________________________________________
>> Alsa-devel mailing list
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>> https://mailman.alsa-project.org/mailman/listinfo/alsa-devel
>>
- Péter
Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
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