ALSA: core: pass audio tstamp config from userspace

Let userspace select audio timestamp config when the
STATUS_EXT ioctl is used, ignore and zero all
other fields
No change for the existing STATUS ioctl, parameters
are treated as read-only.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
index b03a638..72323a8 100644 (file)
--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -753,12 +753,21 @@ int snd_pcm_status(struct snd_pcm_substream *substream,
 }
 
 static int snd_pcm_status_user(struct snd_pcm_substream *substream,
-                              struct snd_pcm_status __user * _status)
+                              struct snd_pcm_status __user * _status,
+                              bool ext)
 {
        struct snd_pcm_status status;
        int res;
-       
+
        memset(&status, 0, sizeof(status));
+       /*
+        * with extension, parameters are read/write,
+        * get audio_tstamp_data from user,
+        * ignore rest of status structure
+        */
+       if (ext && get_user(status.audio_tstamp_data,
+                               (u32 __user *)(&_status->audio_tstamp_data)))
+               return -EFAULT;
        res = snd_pcm_status(substream, &status);
        if (res < 0)
                return res;
@@ -2723,7 +2732,9 @@ static int snd_pcm_common_ioctl1(struct file *file,
        case SNDRV_PCM_IOCTL_SW_PARAMS:
                return snd_pcm_sw_params_user(substream, arg);
        case SNDRV_PCM_IOCTL_STATUS:
-               return snd_pcm_status_user(substream, arg);
+               return snd_pcm_status_user(substream, arg, false);
+       case SNDRV_PCM_IOCTL_STATUS_EXT:
+               return snd_pcm_status_user(substream, arg, true);
        case SNDRV_PCM_IOCTL_CHANNEL_INFO:
                return snd_pcm_channel_info_user(substream, arg);
        case SNDRV_PCM_IOCTL_PREPARE: