Develop Reference

Android running su within app

When I use adb to access my device (Android 4.4.2 straight from the manufactures with their custom rom - its not a regular device - it has built in 2D barcode scanner) it goes straight to having a # which I've read means I have root access. And if I run "id" I get the following:
uid=0(root) gid=0(root) context=u:r:adbd:s0
However, when I run "su" from within my app and then "id" I get the following:
uid=10079(u0_a79) gid=10079(u0_a79) groups=50079(all_a79) context=u:r:untrusted_app:s0n
So it's clearly not running as root.
Is my understanding all wrong, in believing that it should be running as root from within the app, or is there something else I need to do in order to get this working?
Any advice would be much appreciated.
Here is the code I'm currently using to run the su and id commands:
p = Runtime.getRuntime().exec("su");
p.waitFor();
BufferedReader reader = new BufferedReader(new InputStreamReader(p.getInputStream()));
String line = "";
while ((line = reader.readLine())!= null) {
output.append(line + "n");
}
p = Runtime.getRuntime().exec("id");
p.waitFor();
reader = new BufferedReader(new InputStreamReader(p.getInputStream()));
line = "";
while ((line = reader.readLine())!= null) {
output.append(line + "n");
}
One other thing I forgot to mention - I copy the app to /system/priv-app and run it from there. Still no luck.

I had a Chinese tablet with problem like that. Just re-root it (replace su binary). Should work.
P.S. Seeing any code would also help.

There is an android manifest permission you can use to gain root access
<uses-permission android:name="android.permission.FACTORY_TEST" />
Your app will run as a manufacturer test application, running as the root user. Thus making the 'su' command accessible to your app.
However, I doubt that Google Play will allow you to upload in store with such permission.

Android - how to stop continuous terminal action (ping) programmaticaly?

I am working on a simple app but don't know how to stop continuous action in terminal such as PING programmatically.
I just want to know the command, then I'll add it to runtime.getruntime.exec...
I know there's a CTRL+C shortcut in pc but how do I execute this on Android?
Sorry for not adding examples, I'm writing from my phone.

Another way:
Process proc = Runtime.getRuntime().exec("ping 127.0.0.1");
proc.destroy();
As you execute your command, you get the relating process. You can use it to stop your ping, too.

You can't directly send CTRL + C, but take a look at Process.sendSignal() (Android Developers)
First, get the process ID of the ping-process.
Then you can easily send a Process.sendSignal(yourPid, Process.SIGNAL_QUIT);

After debugging for a long time I found out how to solve the problem
"Kill results without the ping statistics being returned".
Get pid of ping process.
Ex:
Progress proc = runtime.exec("ping 192.168.1.1");
where proc will be something like Process[pid=2343], so you need to extract 2343.
Then when you are reading the ping output, you can use
"Runtime.getRuntime().exec("kill -INT " + 2243);" to kill the process.
InputStreamReader reader = new InputStreamReader(proc.getInputStream());
BufferedReader buffer = new BufferedReader(reader);
String line;
while ((line = buffer.readLine()) != null) {
echo.append(line).append("\n");
if (UserStopPing) {
Runtime.getRuntime().exec("kill -INT " + temp);
}
proc.waitFor();
This program will stop ping and you will get the statistic also [variable echo].

You can try this.
There is a CTRL option on your screen. Press that and then enter c.
This might help you.

Just in case people are still looking for a solution to this -- On an Android the equivalent of CTRL+C is "Volume down button" + C on your keyboard. This should stop the ping.

Is it possible to call getevent from an Android service?

Is is possible to run getevent from an Android service and get output similar to what you see when running adb to call getevent from a command prompt on a development machine? When I try something like:
ProcessBuilder builder = new ProcessBuilder()
.command("getevent")
.redirectErrorStream(true)
.start();
BufferedReader reader = new BufferedReader(new InputStreamReader(builder.getInputStream()));
...
the output I get for each device looks like:
could not open /dev/input/event[n], Permission denied
Is it just not possible to access low level information like this because of Android's security protections? Would it be possible on a "rooted" device?
Why I am trying to do this:
I would like to record a user's actions (touch and gesture events) on an Android device for the purpose of usability testing. An accessibility service seems to be the way to go, but the information is not detailed enough. For a swipe gesture, for example, I cannot get the screen coordinates of where the user swiped. I was thinking that getting the low-level input from the touch screen might let me get more detailed information. Maybe there is a better way to do this?
(I'm a newbie in the Android world. This kind of thing is easy on Windows.)

You can do like this.
th = new Thread(new Runnable(){
private Process exec;
#Override
public void run() {
try {
exec = Runtime.getRuntime().exec(new String[]{"su","-c","getevent -t " + device});
InputStreamReader is = new InputStreamReader(
exec.getInputStream());
String s;
BufferedReader br = new BufferedReader(is);
while(((s = br.readLine()) != null) && run){
...
}
is.close();
exec.destroy();
} catch (IOException e) {
e.printStackTrace();
}
}
You must use 'su' to get the root permission, but by this way you can't get the real time event, because there is a buffer size of 4k, you could get data only after contained 4k data.

Search for UIAutomator. This does what you want to do.

Your phone must be rooted to execute getevent/sendevent command.
One way is to install any terminal emulator from play store like Qute: Command Console & Terminal Emulator.
In terminal enter following:
1) su (it'll gain the root access required for getevent)
2) getevent (or getevent -c 8 to output only 8 lines else it would flood the terminal)

Android: Reading adb logcat logs via application

I am trying to write an app which reads the logs created by adb logcat. Following the code on link1 and link2, I have the following code:
try {
Process process = Runtime.getRuntime().exec("logcat");
System.out.println("Process : " + process); // shows process id
BufferedReader bufferedReader = new BufferedReader(
new InputStreamReader(process.getInputStream()));
System.out.println("Buffered reader : " + bufferedReader.readLine());
StringBuilder log = new StringBuilder();
String line;
while ((line = bufferedReader.readLine()) != null) {
log.append(line);
}
TextView tv = (TextView) findViewById(R.id.textView1);
tv.setText(log.toString());
} catch (IOException e) {
}
To test what the buffered reader is reading, I put a println, but I get a message "cannot bind tcp:5038". The above code does not read any logs. I also tried using "logcat *:V" but I did not get logs of even lowest priority.
I gave my app the permission: android.permission.READ_LOGS.
I am testing my code on Android emulator.
Can someone please point out what am I doing wrong.
Thanks for helping.
EDIT:
I tried "logcat -d" and I got one line of log. In the code, it can be observed that a try/catch block has been provided; when I remove the permission READ_LOGS from the app, no exception is raised and the bufferReader simply prints null (Usually when an app does not find a permission it requires, it raises an exception). What is the reason for this behavior ?
EDIT2:
I tried Log.d(TAG, log.toString()) and got more than one line of text. Can someone please explain the last question from the previous edit: when I remove the required permission, why is an exception not raised by the app ?

You are likely getting the message "cannot bind tcp:5038" due to not having
<uses-permission android:name="android.permission.INTERNET" />
in your manifest

You can never get the permission to read logs through Runtime.getRuntime().
The android dev team decided to stop granting these permissions to third-party apps. Only system apps can now get them.
More details:https://code.google.com/p/acra/issues/detail?id=100

run external commands from java(Android) and read continuous output

I want to run excutable such as ping(or any other which gives continuous output) and read its output and print it in my GUI.
I used following method to run my commands:
command=Runtime.getRuntime().exec("ping www.google.com");
and I am reading the output as following:
BufferedReader in = new BufferedReader(new InputStreamReader(command.getInputStream()));
while ((line = in.readLine()) != null) {
System.out.println(line+"\n");
}
this works fine , although display output pretty late compared to time taken when i execute ./excutable using adb -d shell.
As I want to this output(line) in gui so I make a TextView and append the output(line) in it as:
txtview=(TextView)findViewById(R.id.textview);
while ((line = in.readLine()) != null) {
txtview.append(line+"\n");
System.out.println(line+"\n");
}
but this crashes my application.
please tell me how to get over this problem.

If your last block of code is being executed in an Activity, then you are probably blocking the UI thread for too long. This will cause Android to force close your application. Try using AsyncTask to get the output and update your GUI.