Beagleboard application root privileges with Runtime.getRuntime().exec()

Thanks, problem solved. The cause of the issue is that the /system/xbin/su bin does not allow the app root permission, only console user is allowed to execute as root. The solution is to modify su bin.

1. Download Superuser package from git. I used https://github.com/koush/Superuser.

2. You need to install Google NDK package

3. Modify jni/su/su.c using the following code

4. Build using ndk-build (you don't need to build the apk, unless you want the dialog from the Superuser app to ask for root permissions).

5. Install the su bin libs/armeaabi in /system/bin (or replace the su in /system/xbin).

6. Invoke su in your app using /system/bin/su.

=============Code for su.c ======================
#include "utils.h"

static int permissionDenied()
{
        printf("su: permission denied\n");
        return 1;
}

static int executionFailure(char *context)
{
        fprintf(stderr, "su: %s. Error:%s\n", context, strerror(errno));
        return -errno;

}

int main(int argc, char *argv[])
{
        if(setgid(0) || setuid(0))
                return permissionDenied();
         
        char *exec_args[argc + 1];
        exec_args[argc] = NULL;
        exec_args[0] = "sh";
        int i;
        for (i = 1; i < argc; i++)
        {
                exec_args[i] = argv[i];
        }
        execv("/system/bin/sh", exec_args);
        return executionFailure("sh");
}