(Java) SSH -- Running Commands that Prompt for Additional Input, such as "su"

Demonstrates how to run a shell command via SSH where the shell command prompts for additional input from the client. This example demonstrates "su".

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import com.chilkatsoft.*;

public class ChilkatExample {

  static {
    try {
        System.loadLibrary("chilkat");
    } catch (UnsatisfiedLinkError e) {
      System.err.println("Native code library failed to load.\n" + e);
      System.exit(1);
    }
  }

  public static void main(String argv[])
  {
    // This example assumes the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    CkSsh ssh = new CkSsh();

    // Hostname may be an IP address or hostname:
    String hostname = "172.16.16.46";
    int port = 22;

    boolean success = ssh.Connect(hostname,port);
    if (success != true) {
        System.out.println(ssh.lastErrorText());
        return;
        }

    // If receiving output from a command stalls for more than 5 seconds, then stop waiting.
    ssh.put_IdleTimeoutMs(5000);

    success = ssh.AuthenticatePw("myLogin","myPassword");
    if (success != true) {
        System.out.println(ssh.lastErrorText());
        return;
        }

    // Open a session channel. 
    int channelNum = ssh.OpenSessionChannel();
    if (channelNum < 0) {
        System.out.println(ssh.lastErrorText());
        return;
        }

    // Request a pseudo-terminal
    String termType = "dumb";
    int widthInChars = 120;
    int heightInChars = 40;
    int pixWidth = 0;
    int pixHeight = 0;
    success = ssh.SendReqPty(channelNum,termType,widthInChars,heightInChars,pixWidth,pixHeight);
    if (success != true) {
        System.out.println(ssh.lastErrorText());
        return;
        }

    // Start a shell on the channel:
    success = ssh.SendReqShell(channelNum);
    if (success != true) {
        System.out.println(ssh.lastErrorText());
        return;
        }

    // Send the su command.
    // (The SSH server I'm using for testing is a Linux Ubuntu
    // system running OpenSSH.  It is important in this case to send a bare-LF
    // and not a CRLF.)
    String cmd = "su\n";
    success = ssh.ChannelSendString(channelNum,cmd,"ansi");
    if (success != true) {
        System.out.println(ssh.lastErrorText());
        return;
        }

    // Read until we get the prompt for the password:
    success = ssh.ChannelReceiveUntilMatch(channelNum,"Password:","ansi",true);
    if (success != true) {
        System.out.println(ssh.lastErrorText());
        return;
        }

    // Display what we've received so far:
    System.out.println(ssh.getReceivedText(channelNum,"ansi"));

    // Send the password. (This is the equivalent of typing at the shell prompt.)
    // Again, make sure it uses a bare-LF and not a CRLF.
    String password;
    password = "myPassword\n";
    success = ssh.ChannelSendString(channelNum,password,"ansi");
    if (success != true) {
        System.out.println(ssh.lastErrorText());
        return;
        }

    // Read the response until we get the shell prompt (assuming it's successful)
    // In my case, the shell prompt is: "chilkat@vivoMini64:~$ "
    String myShellPrompt = "chilkat@vivoMini64:~$";
    // It will be different in your case.
    success = ssh.ChannelReceiveUntilMatch(channelNum,myShellPrompt,"ansi",true);
    if (success != true) {
        // Check the last-error information and the session log...
        System.out.println(ssh.lastErrorText());
        // Check to see what was received.  
        System.out.println(ssh.getReceivedText(channelNum,"ansi"));
        return;
        }

    // Display what we've received so far.  This clears
    // the internal receive buffer, which is important. 
    // After we send the command, we'll be reading until
    // the next command prompt.  If the command prompt
    // is already in the internal receive buffer, we'll think we're
    // already finished...
    System.out.println(ssh.getReceivedText(channelNum,"ansi"));

    // Send a command.  In this case, we are sending the "ls" command:
    cmd = "ls\n";
    success = ssh.ChannelSendString(channelNum,cmd,"ansi");
    if (success != true) {
        System.out.println(ssh.lastErrorText());
        return;
        }

    // Read until the next command prompt:
    success = ssh.ChannelReceiveUntilMatch(channelNum,myShellPrompt,"ansi",true);
    if (success != true) {
        // Check the last-error information and the session log...
        System.out.println(ssh.lastErrorText());
        // Check to see what was received.  
        System.out.println(ssh.getReceivedText(channelNum,"ansi"));
        return;
        }

    // Display the command output:
    System.out.println(ssh.getReceivedText(channelNum,"ansi"));

    // You may continue sending additional commands.
    // The technique is: send the command, read until the next command prompt,
    // and then fetch/clear the internal receive buffer.

    // We're done, so shut it down..

    // Send an EOF.  This tells the server that no more data will 
    // be sent on this channel.  The channel remains open, and
    // the SSH client may still receive output on this channel.
    success = ssh.ChannelSendEof(channelNum);
    if (success != true) {
        System.out.println(ssh.lastErrorText());
        return;
        }

    // Close the channel:
    success = ssh.ChannelSendClose(channelNum);
    if (success != true) {
        System.out.println(ssh.lastErrorText());
        return;
        }

    // Disconnect
    ssh.Disconnect();
  }
}