jsch and running “sudo su -”

Question

Using jsch

when i run the following cmd \'sudo su -\' the program hangs

[TestNG] Running:
C:\\Users\\brian.crosby\\AppData\\Local\\Temp\\testng-eclip         


        

Answer 1

You are code is missing the rest of the code needed for this to run. You need to initialize the type of channel you need out of the initialized session object. Since you need to be able to run more than one command after each other, you need a Shell type channel:

You should check JSch's examples (i.e. Shell.java), here it is for a quick reference:

/* -*-mode:java; c-basic-offset:2; indent-tabs-mode:nil -*- */
/**
 * This program enables you to connect to sshd server and get the shell prompt.
 *   $ CLASSPATH=.:../build javac Shell.java 
 *   $ CLASSPATH=.:../build java Shell
 * You will be asked username, hostname and passwd. 
 * If everything works fine, you will get the shell prompt. Output will
 * be ugly because of lacks of terminal-emulation, but you can issue commands.
 *
 */
import com.jcraft.jsch.*;
import java.awt.*;
import javax.swing.*;

public class Shell{
  public static void main(String[] arg){

    try{
      JSch jsch=new JSch();

      //jsch.setKnownHosts("/home/foo/.ssh/known_hosts");

      String host=null;
      if(arg.length>0){
        host=arg[0];
      }
      else{
        host=JOptionPane.showInputDialog("Enter username@hostname",
                                         System.getProperty("user.name")+
                                         "@localhost"); 
      }
      String user=host.substring(0, host.indexOf('@'));
      host=host.substring(host.indexOf('@')+1);

      Session session=jsch.getSession(user, host, 22);

      String passwd = JOptionPane.showInputDialog("Enter password");
      session.setPassword(passwd);

      UserInfo ui = new MyUserInfo(){
        public void showMessage(String message){
          JOptionPane.showMessageDialog(null, message);
        }
        public boolean promptYesNo(String message){
          Object[] options={ "yes", "no" };
          int foo=JOptionPane.showOptionDialog(null, 
                                               message,
                                               "Warning", 
                                               JOptionPane.DEFAULT_OPTION, 
                                               JOptionPane.WARNING_MESSAGE,
                                               null, options, options[0]);
          return foo==0;
        }

        // If password is not given before the invocation of Session#connect(),
        // implement also following methods,
        //   * UserInfo#getPassword(),
        //   * UserInfo#promptPassword(String message) and
        //   * UIKeyboardInteractive#promptKeyboardInteractive()

      };

      session.setUserInfo(ui);

      // It must not be recommended, but if you want to skip host-key check,
      // invoke following,
      // session.setConfig("StrictHostKeyChecking", "no");

      //session.connect();
      session.connect(30000);   // making a connection with timeout.

      Channel channel=session.openChannel("shell");

      // Enable agent-forwarding.
      //((ChannelShell)channel).setAgentForwarding(true);

      channel.setInputStream(System.in);
      /*
      // a hack for MS-DOS prompt on Windows.
      channel.setInputStream(new FilterInputStream(System.in){
          public int read(byte[] b, int off, int len)throws IOException{
            return in.read(b, off, (len>1024?1024:len));
          }
        });
       */

      channel.setOutputStream(System.out);

      /*
      // Choose the pty-type "vt102".
      ((ChannelShell)channel).setPtyType("vt102");
      */

      /*
      // Set environment variable "LANG" as "ja_JP.eucJP".
      ((ChannelShell)channel).setEnv("LANG", "ja_JP.eucJP");
      */

      //channel.connect();
      channel.connect(3*1000);
    }
    catch(Exception e){
      System.out.println(e);
    }
  }

  public static abstract class MyUserInfo
                          implements UserInfo, UIKeyboardInteractive{
    public String getPassword(){ return null; }
    public boolean promptYesNo(String str){ return false; }
    public String getPassphrase(){ return null; }
    public boolean promptPassphrase(String message){ return false; }
    public boolean promptPassword(String message){ return false; }
    public void showMessage(String message){ }
    public String[] promptKeyboardInteractive(String destination,
                                              String name,
                                              String instruction,
                                              String[] prompt,
                                              boolean[] echo){
      return null;
    }
  }
}