Examples of org.apache.commons.net.bsd.RCommandClient

org.apache.commons.net.bsd.RCommandClient
RCommandClient is very similar to RExecClient , from which it is derived, and implements the rcmd() facility that first appeared in 4.2BSD Unix. rcmd() is the facility used by the rsh (rshell) and other commands to execute a command on another machine from a trusted host without issuing a password. The trust relationship between two machines is established by the contents of a machine's /etc/hosts.equiv file and a user's .rhosts file. These files specify from which hosts and accounts on those hosts rcmd() requests will be accepted. The only additional measure for establishing trust is that all client connections must originate from a port between 512 and 1023. Consequently, there is an upper limit to the number of rcmd connections that can be running simultaneously. The required ports are reserved ports on Unix systems, and can only be bound by a process running with root permissions (to accomplish this rsh, rlogin, and related commands usualy have the suid bit set). Therefore, on a Unix system, you will only be able to successfully use the RCommandClient class if the process runs as root. However, there is no such restriction on Windows95 and some other systems. The security risks are obvious. However, when carefully used, rcmd() can be very useful when used behind a firewall.
As with virtually all of the client classes in org.apache.commons.net, this class derives from SocketClient. But it overrides most of its connection methods so that the local Socket will originate from an acceptable rshell port. The way to use RCommandClient is to first connect to the server, call the rcommand() method, and then fetch the connection's input, output, and optionally error streams. Interaction with the remote command is controlled entirely through the I/O streams. Once you have finished processing the streams, you should invoke disconnect() to clean up properly.
By default the standard output and standard error streams of the remote process are transmitted over the same connection, readable from the input stream returned by getInputStream() . However, it is possible to tell the rshd daemon to return the standard error stream over a separate connection, readable from the input stream returned by getErrorStream() . You can specify that a separate connection should be created for standard error by setting the boolean separateErrorStream parameter of rcommand() to true . The standard input of the remote process can be written to through the output stream returned by getOutputSream() .

@author Daniel F. Savarese @see org.apache.commons.net.SocketClient @see RExecClient @see RLoginClient

{


    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);

View Full Code Here

   * @param fos
   *            data sink
   * @throws IOException
   */
  public void copyTo(final OutputStream fos) throws IOException {
    final RCommandClient rcmdClient = new RCommandClient();
    rcmdClient.connect(host);
    try {
      rcmdClient.rcommand(System.getProperty("user.name"), user,
          "rcp -f " + file);
      final InputStream is = rcmdClient.getInputStream();
      final OutputStream os = rcmdClient.getOutputStream();
      sendAck(os);
      // read server response header
      final ByteArrayOutputStream bos = new ByteArrayOutputStream();
      for (;;) {
        final int read = is.read();
        if (read < 0) {
          throw new EOFException("unexpected end of stream");
        }
        if (read == '\n') {
          break;
        }
        bos.write(read);
      }
      final String serverResponse = bos.toString("UTF-8");
      // expected header for regular file: C0644 <file-size> <filename>
      if (!serverResponse.isEmpty() && serverResponse.charAt(0) == 'C') {
        int start = 0;
        int end = serverResponse.indexOf(" ", start + 1);
        start = end + 1;
        end = serverResponse.indexOf(" ", start + 1);
        final long filesize = Long.parseLong(serverResponse.substring(
            start, end));
        sendAck(os);
        copyStream(is, fos, filesize);
        expectAck(is);
        sendAck(os);
      } else {
        throw new FileNotFoundException("unexpected server response: "
            + serverResponse.trim());
      }
    } finally {
      rcmdClient.disconnect();
    }
  }

View Full Code Here

   *            number of bytes to be read from the input stream
   * @throws IOException
   */
  public void copyFrom(final InputStream fis, final long filesize)
      throws IOException {
    final RCommandClient rcmdClient = new RCommandClient();
    rcmdClient.connect(host);
    try {
      rcmdClient.rcommand(System.getProperty("user.name"), user,
          "rcp -t " + file);
      final InputStream is = rcmdClient.getInputStream();
      final OutputStream os = rcmdClient.getOutputStream();
      expectAck(is);
      final String header = "C0644 " + filesize + " "
          + new File(file).getName() + "\n";
      os.write(header.getBytes("UTF-8"));
      expectAck(is);
      copyStream(fis, os, filesize);
      sendAck(os);
      expectAck(is);
    } finally {
      rcmdClient.disconnect();
    }
  }

View Full Code Here

{


    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);

View Full Code Here

{


    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);

View Full Code Here

{


    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);

View Full Code Here

{


    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);

View Full Code Here

{


    public static 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);

View Full Code Here

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