Interactive Shell Session from Java

Question

I want to run a series of commands from Java. I came across few forums that explain how to execute multiple commands using getRuntime().exec(command) and defining command as String[]. But I want to input my password into the shell as well. The steps I am trying to do is.

1. sudo su
2. Enter password
3. Execute a shell script that needs sudo access.

Can anyone direct me here please?

Answer 1

At last found a solution that works for me. It may be useful for others in this Stack Overflow Q&A titled: Sudo In Java Process.

The solution involves a fair amount of Java so I'm only going to reference the answer in the original link mentioned above. Here's an example using the code from that answer.

public static void main(String[] args) throws IOException, InterruptedException {
    String password = LinuxCommand.getPasswdForRoot();
    System.out.println("stdout of 'id':");
    Process p = LinuxCommand.runFromRoot("id",password);
    System.out.print(streamToString(p.getInputStream()));
    System.out.println("stdout of 'fdisk -l':");
    p = LinuxCommand.runFromRoot("fdisk -l",password);
    System.out.print(streamToString(p.getInputStream()));
}

The actual implementation of api used above:

import java.awt.BorderLayout;
import java.io.IOException;
import java.io.InputStream;

import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JPasswordField;

public class LinuxCommand {
    static InputStream is;
    static byte[] buff = new byte[8192];
    static int n;
    public static String getPasswdForRoot() throws IOException {
        Process p = Runtime.getRuntime().exec(new String[]{"sh","-c","sudo -S id"});
        is = p.getErrorStream();
        n = is.read(buff, 0, 8192);
        String text = new String(buff,0,n);
        if(text.contains("root"))return null; //not set password
        JPanel panel = new JPanel(new BorderLayout());
        JLabel lab = new JLabel(text);
        panel.add(lab,BorderLayout.NORTH);
        JPasswordField password = new JPasswordField();
        panel.add(password,BorderLayout.SOUTH);
        JOptionPane.showMessageDialog(null, panel);
        byte[] passwd = (new String(password.getPassword())+"\r\n").getBytes();
        p.getOutputStream().write(passwd);
        p.getOutputStream().flush();
        n = is.read(buff, 0, 8192);
        if(n==-1) return new String(password.getPassword());
        text = new String(buff,0,n);
        while(true) {
            lab.setText(text);
            JOptionPane.showMessageDialog(null, panel);
            p = Runtime.getRuntime().exec(new String[]{"sh","-c","sudo -S id"});
            is = p.getErrorStream();
            n = is.read(buff, 0, 8192);
            passwd = (new String(password.getPassword())+"\n").getBytes();
            p.getOutputStream().write(passwd);
            p.getOutputStream().flush();
            n = is.read(buff, 0, 8192);
            if(n==-1) return new String(password.getPassword());
            text = new String(buff,0,n);
        }
    }
    public static Process runFromRoot(String command, String password) throws IOException {
        byte[] passwd = (password+"\n").getBytes(); //for OutputStream better is byte[]
        Process p = Runtime.getRuntime().exec(new String[]{"sh","-c","sudo -S "+command});
        p.getOutputStream().write(passwd);
        p.getOutputStream().flush();
        return p;
    }
}

Along with the output when that code is executed:

stdout of 'id':
uid=0(root) gid=0(root) grupy=0(root)
stdout of 'fdisk -l':

Disk /dev/sda: 640.1 GB, 640135028736 bytes
głowic: 255, sektorów/ścieżkę: 63, cylindrów: 77825, w sumie sektorów: 1250263728
Jednostka = sektorów, czyli 1 * 512 = 512 bajtów
Rozmiar sektora (logiczny/fizyczny) w bajtach: 512 / 4096
Rozmiar we/wy (minimalny/optymalny) w bajtach: 4096 / 4096
Identyfikator dysku: 0xc56b9eef

Urządzenie Rozruch   Początek      Koniec   Bloków   ID  System
/dev/sda1            2048    37064703    18531328   27  Hidden NTFS WinRE
/dev/sda2   *    37064704    37269503      102400    7  HPFS/NTFS/exFAT
/dev/sda3        37269504   456711884   209721190+   7  HPFS/NTFS/exFAT
/dev/sda4       456711946  1250258624   396773339+   f  W95 Rozsz. (LBA)
Partycja 4 nie zaczyna się na granicy bloku fizycznego.
/dev/sda5       456711948   810350729   176819391    7  HPFS/NTFS/exFAT
Partycja 5 nie zaczyna się na granicy bloku fizycznego.
/dev/sda6       810350793   862802954    26226081    7  HPFS/NTFS/exFAT
Partycja 6 nie zaczyna się na granicy bloku fizycznego.
/dev/sda7       862803018  1020078408    78637695+  83  Linux
Partycja 7 nie zaczyna się na granicy bloku fizycznego.
/dev/sda8      1020079368  1229791814   104856223+   7  HPFS/NTFS/exFAT
/dev/sda9      1229791878  1250258624    10233373+   7  HPFS/NTFS/exFAT
Partycja 9 nie zaczyna się na granicy bloku fizycznego.