Caused by: java.io.IOException: Permission denied

1. find where su is, for instance: /system/xbin/su
2. check su's file permission: ls -al /system/xbin/su
3. change mod if necessary: chmod 4755 su
4. try again.

At least in Jelly Bean, SET_DEBUG_APP cannot be held except by apps that are either signed with the firmware's signing key or are installed on the system partition. Ordinary SDK applications cannot hold this permission.

My ROM was messed up. I had to reinstall it. Adding a permission should NOT help. Edit: SuperUser is now giving warning if you don't define the permission, how ever it will still grant su.

Files located on SD card aren't executable. Move the file to internal storage (e.g. to /data/local or, if you get permission denied, to data/local/tmp).

That is how I did it :

String filePath = getFilesDir().getAbsolutePath() + File.separator + "myFileName";
File myFile = new File(filePath);
if (!myFile.canExecute()) {
    Log.d("File is not executable, trying to make it executable ...");
    if (myFile .setExecutable(true)) {
        Log.d("File is executable");
    } else {
        Log.d("Failed to make the File executable");
    }
} else {
    Log.d("File is executable");
}

I find solution, API29+ have more "feature": Removed execute permission for app home directory

The workaround is to rename the executable from "iperf" to "libiperf.so", and create "lib" directory, make "arm64-v8a" subdirectory and put "libiperf.so" there.

Then you can execute iperf

Java.Lang.Process processIperf = Java.Lang.Runtime.GetRuntime().Exec(ApplicationInfo.NativeLibraryDir + "/libiperf.so -v");  
  
Java.IO.BufferedReader bufferedReader = new Java.IO.BufferedReader(new Java.IO.InputStreamReader(processIperf.InputStream));  

For more details and discussions, please go to the internet. No decent solution, there are only more workarounds;)

I think you have misunderstood the usage of 'su'.

Process processStart = Runtime.getRuntime().exec("su");

The above code will create a new process and execute the 'su' command, which will only make the child process to become 'root'.

Your calling process is still a normal process so that you cannot do 'getevent'. Instead you should run this super command in your 'rooted child process' like:

mProcess = new ProcessBuilder()
                        .command("/system/xbin/su")
                        .redirectErrorStream(true).start();

OutputStream out = mProcess.getOutputStream();

String cmd = "getevent /dev/input/event0 \n";
Log.d(TAG, "Native command = " + cmd);
out.write(cmd.getBytes());

https://developer.android.com/about/versions/10/behavior-changes-10#execute-permission

When targeting API 29 (Android 10 / Q) or above, it is not possible anymore to have execute permission for files stored within the app's home directory (data), which is exactly what you are describing (/data/data/%package%/).

This Android 10 modification was introduced in commit: https://android-review.googlesource.com/c/platform/system/sepolicy/+/804149 and was then confirmed officially by Google here: https://issuetracker.google.com/issues/128554619

This significant change is being discussed by various projects, in termux/termux-app#1072 for instance. One recommended and (hopefully) future-proof way is to extract program binaries into the application's native lib directory (with android:extractNativeLibs=true), where files can still be executed but are stored read-only for improved security.

Here are examples showing how to handle this change, in Termux with commit f6c3b6f in the android-10 branch or in this other project showing how to run the Erlang runtime on Android by exctrating all the files from a .zip archive into the jniLibs/"abi" subdirectory ("abi" being arm64-v8a for 64-bit ARM, armeabi-v7a for 32-bit ARM, etc.) with the imposed lib___.so filename format expected by the Android platform. Executable files can simply be moved in the right project folder manually, the important part is to use the lib___.so format for the filenames.

In the Android Manifest file, setting the attribute android:extractNativeLibs="true" will get these lib___.so files extracted at installation time in the right native lib directory, with support for execute permission. Symlinks can finally be created if needed in the usual app directory to use the regular executable names, instead of the harder-to-manipulate lib___.so versions.

Thanks, Jérôme

You are using exec(String[] cmdarray) Executes the specified command and arguments in a separate process. But are sending the directory as the command and the script name as a parameter.

Try:

String[] cmdArray = new String[1];
cmdArray[0]=DIR_CODE + FILE;

Process p=null;
p = Runtime.getRuntime().exec(cmdArray);

When you execute 'su', you should have root access within that process. The app should then automatically ask for root permission to the user via a dialog box. This dialog box is provided by android but is only present in devices that have been rooted.

This blog post has an example that might help you:

http://www.stealthcopter.com/blog/2010/01/android-requesting-root-access-in-your-app/

The comments at the end are very informative as well.