Java/Network Protocol/Net Command

Connects to an rexec server

/*
 * Copyright 2001-2005 The Apache Software Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package examples;
import java.io.IOException;
import org.apache.rumons.net.bsd.RExecClient;
/***
 * This is an example program demonstrating how to use the RExecClient class.
 * This program connects to an rexec server and requests that the
 * given command be executed on the server.  It then reads input from stdin
 * (this will be line buffered on most systems, so don"t expect character
 * at a time interactivity), passing it to the remote process and writes
 * the process stdout and stderr to local stdout.
 * <p>
 * Example: java rexec myhost myusername mypassword "ps -aux"
 * <p>
 * Usage: rexec <hostname> <username> <password> <command>
 * <p>
 ***/
// This class requires the IOUtil support class!
public class rexec
{
    public static final void main(String[] args)
    {
        String server, username, password, command;
        RExecClient client;
        if (args.length != 4)
        {
            System.err.println(
                "Usage: rexec <hostname> <username> <password> <command>");
            System.exit(1);
            return ; // so compiler can do proper flow control analysis
        }
        client = new RExecClient();
        server = args[0];
        username = args[1];
        password = args[2];
        command = args[3];
        try
        {
            client.connect(server);
        }
        catch (IOException e)
        {
            System.err.println("Could not connect to server.");
            e.printStackTrace();
            System.exit(1);
        }
        try
        {
            client.rexec(username, password, command);
        }
        catch (IOException e)
        {
            try
            {
                client.disconnect();
            }
            catch (IOException f)
            {}
            e.printStackTrace();
            System.err.println("Could not execute command.");
            System.exit(1);
        }

        IOUtil.readWrite(client.getInputStream(), client.getOutputStream(),
                         System.in, System.out);
        try
        {
            client.disconnect();
        }
        catch (IOException e)
        {
            e.printStackTrace();
            System.exit(1);
        }
        System.exit(0);
    }
}

Connects to an rlogin daemon

/*
 * Copyright 2001-2005 The Apache Software Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package examples;
import java.io.IOException;
import org.apache.rumons.net.bsd.RLoginClient;
/***
 * This is an example program demonstrating how to use the RLoginClient
 * class. This program connects to an rlogin daemon and begins to
 * interactively read input from stdin (this will be line buffered on most
 * systems, so don"t expect character at a time interactivity), passing it
 * to the remote login process and writing the remote stdout and stderr
 * to local stdout.  If you don"t have .rhosts or hosts.equiv files set up,
 * the rlogin daemon will prompt you for a password.
 * <p>
 * On Unix systems you will not be able to use the rshell capability
 * unless the process runs as root since only root can bind port addresses
 * lower than 1024.
 * <p>
 * JVM"s using green threads will likely have problems if the rlogin daemon
 * requests a password.  This program is merely a demonstration and is
 * not suitable for use as an application, especially given that it relies
 * on line buffered input from System.in.  The best way to run this example
 * is probably from a Win95 dos box into a Unix host.
 * <p>
 * Example: java rlogin myhost localusername remoteusername vt100
 * <p>
 * Usage: rlogin <hostname> <localuser> <remoteuser> <terminal>
 * <p>
 ***/
// This class requires the IOUtil support class!
public class rlogin
{
    public static final void main(String[] args)
    {
        String server, localuser, remoteuser, terminal;
        RLoginClient client;
        if (args.length != 4)
        {
            System.err.println(
                "Usage: rlogin <hostname> <localuser> <remoteuser> <terminal>");
            System.exit(1);
            return ; // so compiler can do proper flow control analysis
        }
        client = new RLoginClient();
        server = args[0];
        localuser = args[1];
        remoteuser = args[2];
        terminal = args[3];
        try
        {
            client.connect(server);
        }
        catch (IOException e)
        {
            System.err.println("Could not connect to server.");
            e.printStackTrace();
            System.exit(1);
        }
        try
        {
            client.rlogin(localuser, remoteuser, terminal);
        }
        catch (IOException e)
        {
            try
            {
                client.disconnect();
            }
            catch (IOException f)
            {}
            e.printStackTrace();
            System.err.println("rlogin authentication failed.");
            System.exit(1);
        }

        IOUtil.readWrite(client.getInputStream(), client.getOutputStream(),
                         System.in, System.out);
        try
        {
            client.disconnect();
        }
        catch (IOException e)
        {
            e.printStackTrace();
            System.exit(1);
        }
        System.exit(0);
    }
}

Connects to an rshell daemon

/*
 * Copyright 2001-2005 The Apache Software Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package examples;
import java.io.IOException;
import org.apache.rumons.net.bsd.RCommandClient;
/***
 * This is an example program demonstrating how to use the RCommandClient
 * class. This program connects to an rshell daemon and requests that the
 * given command be executed on the server.  It then reads input from stdin
 * (this will be line buffered on most systems, so don"t expect character
 * at a time interactivity), passing it to the remote process and writes
 * the process stdout and stderr to local stdout.
 * <p>
 * On Unix systems you will not be able to use the rshell capability
 * unless the process runs as root since only root can bind port addresses
 * lower than 1024.
 * <p>
 * Example: java rshell myhost localusername remoteusername "ps -aux"
 * <p>
 * Usage: rshell <hostname> <localuser> <remoteuser> <command>
 * <p>
 ***/
// This class requires the IOUtil support class!
public class rshell
{
    public static final void main(String[] args)
    {
        String server, localuser, remoteuser, command;
        RCommandClient client;
        if (args.length != 4)
        {
            System.err.println(
                "Usage: rshell <hostname> <localuser> <remoteuser> <command>");
            System.exit(1);
            return ; // so compiler can do proper flow control analysis
        }
        client = new RCommandClient();
        server = args[0];
        localuser = args[1];
        remoteuser = args[2];
        command = args[3];
        try
        {
            client.connect(server);
        }
        catch (IOException e)
        {
            System.err.println("Could not connect to server.");
            e.printStackTrace();
            System.exit(1);
        }
        try
        {
            client.rcommand(localuser, remoteuser, command);
        }
        catch (IOException e)
        {
            try
            {
                client.disconnect();
            }
            catch (IOException f)
            {}
            e.printStackTrace();
            System.err.println("Could not execute command.");
            System.exit(1);
        }

        IOUtil.readWrite(client.getInputStream(), client.getOutputStream(),
                         System.in, System.out);
        try
        {
            client.disconnect();
        }
        catch (IOException e)
        {
            e.printStackTrace();
            System.exit(1);
        }
        System.exit(0);
    }
}

Finger client

 
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintStream;
import java.net.Socket;
import java.util.StringTokenizer;
public class Finger {
  public static void main(String[] arguments) throws Exception {
    StringTokenizer split = new StringTokenizer(arguments[0], "@");
    String user = split.nextToken();
    String host = split.nextToken();
    Socket digit = new Socket(host, 79);
    digit.setSoTimeout(20000);
    PrintStream out = new PrintStream(digit.getOutputStream());
    out.print(user + "\015\012");
    BufferedReader in = new BufferedReader(new InputStreamReader(digit.getInputStream()));
    boolean eof = false;
    while (!eof) {
      String line = in.readLine();
      if (line != null)
        System.out.println(line);
      else
        eof = true;
    }
    digit.close();
  }
}

Implement the finger command in Java

/*
 * Copyright 2001-2005 The Apache Software Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package examples;
import java.io.IOException;
import java.net.InetAddress;
import java.net.UnknownHostException;
import org.apache.rumons.net.FingerClient;
/***
 * This is an example of how you would implement the finger command
 * in Java using NetComponents.  The Java version is much shorter.
 * But keep in mind that the Unix finger command reads all sorts of
 * local files to output local finger information.  This program only
 * queries the finger daemon.
 * <p>
 * The -l flag is used to request long output from the server.
 * <p>
 ***/
public class finger
{
    public static final void main(String[] args)
    {
        boolean longOutput = false;
        int arg = 0, index;
        String handle, host;
        FingerClient finger;
        InetAddress address = null;
        // Get flags.  If an invalid flag is present, exit with usage message.
        while (arg < args.length && args[arg].startsWith("-"))
        {
            if (args[arg].equals("-l"))
                longOutput = true;
            else
            {
                System.err.println("usage: finger [-l] [[[handle][@<server>]] ...]");
                System.exit(1);
            }
            ++arg;
        }

        finger = new FingerClient();
        // We want to timeout if a response takes longer than 60 seconds
        finger.setDefaultTimeout(60000);
        if (arg >= args.length)
        {
            // Finger local host
            try
            {
                address = InetAddress.getLocalHost();
            }
            catch (UnknownHostException e)
            {
                System.err.println("Error unknown host: " + e.getMessage());
                System.exit(1);
            }
            try
            {
                finger.connect(address);
                System.out.print(finger.query(longOutput));
                finger.disconnect();
            }
            catch (IOException e)
            {
                System.err.println("Error I/O exception: " + e.getMessage());
                System.exit(1);
            }
            return ;
        }
        // Finger each argument
        while (arg < args.length)
        {
            index = args[arg].lastIndexOf("@");
            if (index == -1)
            {
                handle = args[arg];
                try
                {
                    address = InetAddress.getLocalHost();
                }
                catch (UnknownHostException e)
                {
                    System.err.println("Error unknown host: " + e.getMessage());
                    System.exit(1);
                }
            }
            else
            {
                handle = args[arg].substring(0, index);
                host = args[arg].substring(index + 1);
                try
                {
                    address = InetAddress.getByName(host);
                }
                catch (UnknownHostException e)
                {
                    System.err.println("Error unknown host: " + e.getMessage());
                    System.exit(1);
                }
            }
            System.out.println("[" + address.getHostName() + "]");
            try
            {
                finger.connect(address);
                System.out.print(finger.query(longOutput, handle));
                finger.disconnect();
            }
            catch (IOException e)
            {
                System.err.println("Error I/O exception: " + e.getMessage());
                System.exit(1);
            }
            ++arg;
            if (arg != args.length)
                System.out.print("\n");
        }
    }
}

Implement the Linux fwhois command in Java

/*
 * Copyright 2001-2005 The Apache Software Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package examples;
import java.io.IOException;
import java.net.InetAddress;
import java.net.UnknownHostException;
import org.apache.rumons.net.WhoisClient;
/***
 * This is an example of how you would implement the Linux fwhois command
 * in Java using NetComponents.  The Java version is much shorter.
 * <p>
 ***/
public class fwhois
{
    public static final void main(String[] args)
    {
        int index;
        String handle, host;
        InetAddress address = null;
        WhoisClient whois;
        if (args.length != 1)
        {
            System.err.println("usage: fwhois handle[@<server>]");
            System.exit(1);
        }
        index = args[0].lastIndexOf("@");
        whois = new WhoisClient();
        // We want to timeout if a response takes longer than 60 seconds
        whois.setDefaultTimeout(60000);
        if (index == -1)
        {
            handle = args[0];
            host = WhoisClient.DEFAULT_HOST;
        }
        else
        {
            handle = args[0].substring(0, index);
            host = args[0].substring(index + 1);
        }
        try
        {
            address = InetAddress.getByName(host);
        }
        catch (UnknownHostException e)
        {
            System.err.println("Error unknown host: " + e.getMessage());
            System.exit(1);
        }
        System.out.println("[" + address.getHostName() + "]");
        try
        {
            whois.connect(address);
            System.out.print(whois.query(handle));
            whois.disconnect();
        }
        catch (IOException e)
        {
            System.err.println("Error I/O exception: " + e.getMessage());
            System.exit(1);
        }
    }
}

Use the TimeTCPClient and TimeUDPClient: simple Unix rdate

/*
 * Copyright 2001-2005 The Apache Software Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package examples;
import java.io.IOException;
import java.net.InetAddress;
import org.apache.rumons.net.TimeTCPClient;
import org.apache.rumons.net.TimeUDPClient;
/***
 * This is an example program demonstrating how to use the TimeTCPClient
 * and TimeUDPClient classes.  It"s very similar to the simple Unix rdate
 * command.  This program connects to the default time service port of a
 * specified server, retrieves the time, and prints it to standard output.
 * The default is to use the TCP port.  Use the -udp flag to use the UDP
 * port.  You can test this program by using the NIST time server at
 * 132.163.135.130 (warning: the IP address may change).
 * <p>
 * Usage: rdate [-udp] <hostname>
 * <p>
 * <p>
 * @author Daniel F. Savarese
 ***/
public class rdate
{
    public static final void timeTCP(String host) throws IOException
    {
        TimeTCPClient client = new TimeTCPClient();
        // We want to timeout if a response takes longer than 60 seconds
        client.setDefaultTimeout(60000);
        client.connect(host);
        System.out.println(client.getDate().toString());
        client.disconnect();
    }
    public static final void timeUDP(String host) throws IOException
    {
        TimeUDPClient client = new TimeUDPClient();
        // We want to timeout if a response takes longer than 60 seconds
        client.setDefaultTimeout(60000);
        client.open();
        System.out.println(client.getDate(InetAddress.getByName(host)).toString());
        client.close();
    }

    public static final void main(String[] args)
    {
        if (args.length == 1)
        {
            try
            {
                timeTCP(args[0]);
            }
            catch (IOException e)
            {
                e.printStackTrace();
                System.exit(1);
            }
        }
        else if (args.length == 2 && args[0].equals("-udp"))
        {
            try
            {
                timeUDP(args[1]);
            }
            catch (IOException e)
            {
                e.printStackTrace();
                System.exit(1);
            }
        }
        else
        {
            System.err.println("Usage: rdate [-udp] <hostname>");
            System.exit(1);
        }
    }
}