[alsa-devel] [PATCH v1 3/4] alsabat: add XRUN injections function

[Takashi Iwai]

On Thu, 31 Aug 2017 15:37:08 +0200,
Zhang Keqiao wrote:
> 
> This patch add XRUN injections function, alsabat can trigger the XRUNs
> by writing the 'XRUN INJECTION' files.
> 
> Signed-off-by: Zhang Keqiao <keqiao.zhang at intel.com>
> ---
>  bat/bat.c    | 97 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++--
>  bat/common.h |  6 ++++
>  2 files changed, 101 insertions(+), 2 deletions(-)
> 
> diff --git a/bat/bat.c b/bat/bat.c
> index b12e5d3..20fa926 100644
> --- a/bat/bat.c
> +++ b/bat/bat.c
> @@ -127,8 +127,81 @@ static void get_sine_frequencies(struct bat *bat, char *freq)
>  	}
>  }
>  
> -/* parse the card and pcm ID of playback device and capture device */
> -/* Then we can get the path for specify device to do the XRUN injection */
> +static int xrun_injection(struct bat *bat)
> +{
> +	char playback_file[MAX_PATH + MAX_FILE];
> +	char capture_file[MAX_PATH + MAX_FILE];
> +	char filename[MAX_FILE] = XRUN_INJECTION_FILE;
> +	char playback_filepath[MAX_PATH] = PLAYBACK_XRUN_INJECTION_PATH;
> +	char capture_filepath[MAX_PATH] = CAPTURE_XRUN_INJECTION_PATH;
> +	FILE *fp, *fc;
> +
> +	if (bat->xrun_playback) {
> +		/* replace the card ID and PCM ID in macro for xrun injection path */
> +		sprintf(playback_filepath, playback_filepath, bat->playback.card_id,
> +				bat->playback.pcm_id);

This doesn't look sane.  The format path shouldn't be same as the
target.  There is no guarantee that the format path is evaluated
before storing the resultant string.

Moreover: 

> +#define PLAYBACK_XRUN_INJECTION_PATH	"/proc/asound/card%s/pcm%sp/sub0"
> +#define CAPTURE_XRUN_INJECTION_PATH	"/proc/asound/card%s/pcm%sc/sub0"

This assumes the PCM#0, which isn't always true.


thanks,

Takashi