Can i write from MediaRecorder to my android / linux pipe's?

Question

I'm creating android pipe with command

System.Diagnostics.Process.Start("mkfifo", $"/data/user/0/ru.petrovip.proxyclient/files/videopipe").WaitForExit();

This command make pipe videopipe , through application.

And open this pipe in application

var VideoStream = System.IO.File.Open("/data/user/0/ru.petrovip.proxyclient/files/videopipe", FileMode.Open);

Pipe is working, but i if start using MediaRecorder for my pipe, i catch error Java.Lang.IllegalStateException at MRecorder.Prepare();

MediaRecorder MRecorder = new MediaRecorder();

MRecorder.SetAudioSource(AudioSource.Mic);
MRecorder.SetVideoSource(VideoSource.Surface);
MRecorder.SetOutputFormat(OutputFormat.ThreeGpp);
MRecorder.SetOutputFile(ParcelFileDescriptor.FromFd((int)VideoStream.Handle).FileDescriptor);
MRecorder.SetVideoSize(DisplayMetrics.WidthPixels, DisplayMetrics.HeightPixels);
MRecorder.SetAudioEncoder(AudioEncoder.AmrNb);
MRecorder.SetVideoEncoder(VideoEncoder.H264);
MRecorder.SetVideoEncodingBitRate(512 * 1000);
MRecorder.SetVideoFrameRate(30);
MRecorder.Prepare();

Exception

01-18 20:23:55.471 E/MediaRecorder( 5990): prepare failed: -38
01-18 20:23:55.467 W/vip.proxyclient( 5990): type=1400 audit(0.0:876): avc: denied { read write } for path="/data/data/ru.petrovip.proxyclient/files/videopipe" dev="mmcblk0p24" ino=5435 scontext=u:r:mediaserver:s0 tcontext=u:object_r:app_data_file:s0:c512,c768 tclass=fifo_file permissive=0
01-18 20:24:01.625 W/System.err( 5990): java.lang.IllegalStateException
01-18 20:24:01.627 W/System.err( 5990):     at android.media.MediaRecorder._prepare(Native Method)
01-18 20:24:01.628 W/System.err( 5990):     at android.media.MediaRecorder.prepare(MediaRecorder.java:988)
01-18 20:24:01.629 W/System.err( 5990):     at crc64c1965aae109aaff4.MainActivity.n_onCreate(Native Method)
01-18 20:24:01.629 W/System.err( 5990):     at crc64c1965aae109aaff4.MainActivity.onCreate(MainActivity.java:31)
01-18 20:24:01.630 W/System.err( 5990):     at android.app.Activity.performCreate(Activity.java:7023)
01-18 20:24:01.631 W/System.err( 5990):     at android.app.Activity.performCreate(Activity.java:7014)
01-18 20:24:01.632 W/System.err( 5990):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1214)
01-18 20:24:01.633 W/System.err( 5990):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2758)
01-18 20:24:01.637 W/System.err( 5990):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2883)
01-18 20:24:01.638 W/System.err( 5990):     at android.app.ActivityThread.-wrap11(Unknown Source:0)
01-18 20:24:01.639 W/System.err( 5990):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1613)
01-18 20:24:01.640 W/System.err( 5990):     at android.os.Handler.dispatchMessage(Handler.java:106)
01-18 20:24:01.640 W/System.err( 5990):     at android.os.Looper.loop(Looper.java:164)
01-18 20:24:01.641 W/System.err( 5990):     at android.app.ActivityThread.main(ActivityThread.java:6523)
01-18 20:24:01.642 W/System.err( 5990):     at java.lang.reflect.Method.invoke(Native Method)
01-18 20:24:01.643 W/System.err( 5990):     at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438)
01-18 20:24:01.649 W/System.err( 5990):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:857)

For other system pipe's /dev/null , /dev/zero this will work correctly, without any errors.

Is this due to security restrictions and are there other ways out of this problem?

Answer 1

This problem occurs when enabled by enabled SELinux status. You need disable him by command

setenforce 0

Note: this method work only if you'r device rooted.