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[])
  {
    //  Important: It is helpful to send the contents of the
    //  ssh.LastErrorText property when requesting support.

    CkSsh ssh = new CkSsh();

    //  Any string automatically begins a fully-functional 30-day trial.
    boolean success;
    success = ssh.UnlockComponent("30-day trial");
    if (success != true) {
        System.out.println(ssh.lastErrorText());
        return;
    }

    String hostname;
    int port;

    //  Hostname may be an IP address or hostname:
    hostname = "192.168.1.117";
    port = 22;

    //  Keep a session log, which is available via the SessionLog
    //  property:
    ssh.put_KeepSessionLog(true);

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

    //  When reading, if no additional data arrives for more than
    //  5 seconds, then abort:
    ssh.put_IdleTimeoutMs(5000);

    //  SSH Server Authentication
    //  If there is no login/password required, you must still call
    //  AuthenticatePw and use any values for login/password.
    success = ssh.AuthenticatePw("chilkat","myPassword");
    if (success != true) {
        System.out.println(ssh.lastErrorText());
        System.out.println(ssh.sessionLog());
        return;
    }

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

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

    //  Start a shell on the channel:
    success = ssh.SendReqShell(channelNum);
    if (success != true) {
        System.out.println(ssh.lastErrorText());
        System.out.println(ssh.sessionLog());
        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;
    cmd = "su\n";
    success = ssh.ChannelSendString(channelNum,cmd,"ansi");
    if (success != true) {
        System.out.println(ssh.lastErrorText());
        System.out.println(ssh.sessionLog());
        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());
        System.out.println(ssh.sessionLog());
        return;
    }

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

    //  Send the password.
    //  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());
        System.out.println(ssh.sessionLog());
        return;
    }

    //  Read the response until we get the shell prompt (assuming it's successful)
    //  In my case, the shell prompt is: "root@ubuntu:/home/chilkat# "
    //  It will be different in your case.
    success = ssh.ChannelReceiveUntilMatch(channelNum,"root@ubuntu:/home/chilkat#","ansi",true);
    if (success != true) {
        //  Check the last-error information and the session log...
        System.out.println(ssh.lastErrorText());
        System.out.println(ssh.sessionLog());
        //  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());
        System.out.println(ssh.sessionLog());
        return;
    }

    //  Read until the next command prompt:
    success = ssh.ChannelReceiveUntilMatch(channelNum,"root@ubuntu:/home/chilkat#","ansi",true);
    if (success != true) {
        //  Check the last-error information and the session log...
        System.out.println(ssh.lastErrorText());
        System.out.println(ssh.sessionLog());
        //  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());
        System.out.println(ssh.sessionLog());
        return;
    }

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

    //  Disconnect
    ssh.Disconnect();
  }
}