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

I'm running JB 4.1.2 on  a BeagleBoard-xM but i can't run any root command using Runtime.getRuntime().exec().
I've tried anything but i got:

java.io.IOException: Error running exec(). Command: [echo] Working Directory: null Environment: null

With original /system/xbin/su command, or at least

Permission Denied or no output replacing original "su" command with a custom one (taken from SuperSu or SuperUser application, ARM build).

I've also tried to change "su" command group and permission and running application as a system app.
I've tried any command like "sh -c" "su -c" or libsuperuser (from chainfire) or also using a custom JNI lib that invoke system("su...");
Nothing change, no luck.

su command only works by terminal or through adb shell.

I need to run some echo command to use board leds from my application, how can solve it?

Thanks

  • I'm having the same issue since I'm trying to exec shell comands that requireroot access. Let me know if you found a workaroumd.

  • 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");
    }

  • Hi
    Can you please send me the recompiled SU binaries please. I dont have a much knowledge in using NDK can you please send me the modified file please.