Android Question running the app with ROOT permission

[yaniv hanya]

i built an app the send commands to ModBus protocol. the people that built the slave (the device that get the commands), says that the app have to grant a "root" permission for sending the commands.
how do i give the app ROOT permission? can it be done via the app menifest?

 

[moster67]

don't know if it is still relevant but see this thread:

SuperUser: Acquiring root permissions, the easy way.

version 2.4 Introduction We all have seen various apps asking for superuser permissions to do weird things with our devices and many times we wondered how they do it. Well, with SupeUser, accessing a rooted device is as simple as a function call! Latest package (library files and samples)...

www.b4x.com

There might be other examples in the forum how to obtain it - I didn't search that much...

 

[agraham]

The device itself must be rooted before any app can access super user permissions.

 

[DonManfred]

how do i give the app ROOT permission?

You need to ROOT your device. Note that you loose warranty when rooting.

 

[yaniv hanya]

Are you all sure i have to root the device? the company that use the the BodBus send me a working apk of java and i don't sure the device it work on is rooted. (i can't check it on my phone since it required UART connector).

 

[Erel]

(Even if your device is rooted, the app will not run with root permissions by default.)

You can't have any special permissions on unrooted devices unless your APK is signed with the OS private key. Only possible if you are building a custom ROM.

 

[yaniv hanya]

it should be a custom ROM, or i can create a certificate that will give SU permission? the process described here-

How to sign Android app with system signature?

I've downloaded and compiled Android 2.1 version with signed-google_ion-ota-14721.zip image for my HTC phone. The compile completed successfully and so the system image flash. How can I sign my own

stackoverflow.com

required ROOTED device?

 

[Erel]

or i can create a certificate that will give SU permission?

Of course not. It will be a big security issue.

Only the manufacturer has the OS key.

 

[agraham]

company that use the the BodBus send me a working apk of java and i don't sure the device it work on is rooted

If that is the case then they seem to be wrong about needing root permission - which would be a strange limitation for an app that, I assume, only needs to access a USB serial device..

 

[yaniv hanya]

well... the problem is that without this permission the bits doesn't go through to the microchip. I guess I wrong and the device is rooted. I only saw a video showing it. I"l investigate more.

But thanks all, I got my answers. You are great…

 

[yaniv hanya]

I install the app via the ADB.
Will she later be able to get automatic updates

 

[yaniv hanya]

don't know if it is still relevant but see this thread:

SuperUser: Acquiring root permissions, the easy way.

version 2.4 Introduction We all have seen various apps asking for superuser permissions to do weird things with our devices and many times we wondered how they do it. Well, with SupeUser, accessing a rooted device is as simple as a function call! Latest package (library files and samples)...

www.b4x.com

There might be other examples in the forum how to obtain it - I didn't search that much...

it didn't wokred for me. i allways get "permission error", do any body have another idea?

 

[agraham]

We've already told you, if the app needs root permissions then the device needs to be rooted. Otherwise it will not work.

 

[mangojack]

Opening statement from the SuperUser lib thread ...

Introduction

We all have seen various apps asking for superuser permissions to do weird things with our devices and many times we wondered how they do it. Well, with SupeUser, accessing a rooted device is as simple as a function call!

 

[yaniv hanya]

I"m sorry. i didn't explain myself. the device is rooted, and the superuser lib does recognize it as rooted. but the commands dosen't run. it gives error message- "permission denid", all though i think that in the menifest i gave all the permission needed.

however, since the superuser lib is old, i think i will not find a way to work it up. so, what i try to understand is how to build a superuser app from B4A. since the java exmple they send me does work. i wonder if it is possible from the app design, or it should be in the installation process only.

 

[Erel]

Can you upload the Java project?

 

[yaniv hanya]

This is link to ZIP file i uploaded to my server, it was too big-

https://www.shoresh.org.il/usersfiles/serialtest.zip

As i wrote, the purpose is to send bits to modbus protocol, via UART connection.

thanks...

 

[Erel]

This project is based on native (C/C++) library.
You will need to create a wrapper for this library.

Eventually it opens /dev/ttySAC0. You can try to open it with File.OpenInput.

 

[yaniv hanya]

thanks a lot erel.

 

[yaniv hanya]

Eventually it opens /dev/ttySAC0. You can try to open it with File.OpenInput.

I tried this code as you suggested here and here

    Dim out As OutputStream = File.OpenOutput("/dev/ttySAC0", "", False)

and that what i got

Spoiler

Error occurred on line: 53 (Main)
java.io.FileNotFoundException: /dev/ttySAC0 (Permission denied)
at java.io.FileOutputStream.open(Native Method)
at java.io.FileOutputStream.<init>(FileOutputStream.java:221)
at anywheresoftware.b4a.objects.streams.File.OpenOutput(File.java:448)
at java.lang.reflect.Method.invoke(Native Method)
at anywheresoftware.b4a.shell.Shell.runMethod(Shell.java:732)
at anywheresoftware.b4a.shell.Shell.raiseEventImpl(Shell.java:348)
at anywheresoftware.b4a.shell.Shell.raiseEvent(Shell.java:255)
at java.lang.reflect.Method.invoke(Native Method)
at anywheresoftware.b4a.ShellBA.raiseEvent2(ShellBA.java:144)
at anywheresoftware.b4a.BA.raiseEvent2(BA.java:180)
at anywheresoftware.b4a.BA.raiseEvent(BA.java:176)
at anywheresoftware.b4a.objects.ViewWrapper$1.onClick(ViewWrapper.java:80)
at android.view.View.performClick(View.java:5637)
at android.view.View$PerformClick.run(View.java:22429)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6121)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:889)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:779)

If it works like that it would be great.
Do you have any idea what permission I need?