Re: [JSch-users] ChannelExec unable to execute top command

[Oberhuber, M. <Mar...@wi...>]

I'd think that this is expected behavior.

"top" needs a Terminal emulation in order to move the
cursor around etc -- but ChannelExec just provides a
raw input and output stream without terminal emulation.

You'll need ChannelShell if you want to run top. And,
a Terminal emulation connected to your Streams such 
as PuTTY or the Terminal component from our Eclipse 
Open Source project: http://www.eclipse.org/dsdp/tm/

Cheers,
--
Martin Oberhuber, Senior Member of Technical Staff, Wind River
Target Management Project Lead, DSDP PMC Member
http://www.eclipse.org/dsdp/tm
 
 

> -----Original Message-----
> From: Amol Kulkarni [mailto:am...@gm...] 
> Sent: Wednesday, September 24, 2008 10:28 AM
> To: jsc...@li...
> Subject: [JSch-users] ChannelExec unable to execute top command
> 
> Hi,
> 
> I want to execute system command using ChannelExec on remote Linux
> machine. I am not able to execute "top" command. I am able to execute
> "top -b" (batch mode) command properly. I want to use ChannelExec to
> avoid getting garbage characters that I receive when I use
> ChannelShell.
> On the error stream, it writes the following:
> 
> TERM environment variable not set.
> 
> Here is the sample application:
> 
> package com.appperfect.common.main;
> 
> import java.io.BufferedReader;
> import java.io.InputStreamReader;
> import java.io.OutputStream;
> 
> import com.jcraft.jsch.Channel;
> import com.jcraft.jsch.ChannelExec;
> import com.jcraft.jsch.ChannelShell;
> import com.jcraft.jsch.JSch;
> import com.jcraft.jsch.Logger;
> import com.jcraft.jsch.Session;
> import com.jcraft.jsch.UserInfo;
> 
> public class SSHSample
> {
> 	private static class MyUserInfo implements UserInfo
> 	{
> 		private String passwd;
> 
> 		MyUserInfo(String passwd)
> 		{
> 			this.passwd = passwd;
> 		}
> 
> 		public String getPassword()
> 		{
> 			return passwd;
> 		}
> 
> 		public boolean promptYesNo(String str)
> 		{
> 			return true;
> 		}
> 
> 		public String getPassphrase()
> 		{
> 			return null;
> 		}
> 
> 		public boolean promptPassphrase(String message)
> 		{
> 			return true;
> 		}
> 
> 		public boolean promptPassword(String message)
> 		{
> 			return true;
> 		}
> 
> 		public void showMessage(String message)
> 		{
> 		}
> 	}
> 	
> 	
> 	
> 	public static void main(String[] args)
> 	{
> 		if(args.length != 4)
> 		{
> 			System.out.println("Usage : SSHSample 
> hostName UserName Password Type");
> 			System.exit(0);
> 		}
> 		
> 		final String hostName = args[0];
> 		final String userName = args[1];
> 		final String password = args[2];
> 		final String channelTye = args[3];
> 		
> 		JSch.setLogger(new Logger()
> 		{
> 
> 			public boolean isEnabled(int level) 
> {return true;}
> 
> 			public void log(int level, String message) {
> 				System.out.println(message);
> 			}
> 		});
> 		
> 		final String command = "top";
> 		final JSch jsch = new JSch();
> 		Session session = null;
> 		Channel channel = null;
> 		boolean exec = channelTye.equals("exec");
> 		try
> 		{
> 			session = jsch.getSession(userName, 
> hostName, 22);
> 			session.setUserInfo(new MyUserInfo(password));
> 			session.setDaemonThread(false);
> 			session.connect();
> 			channel = session.openChannel(channelTye);
> 			OutputStream os = channel.getOutputStream();
> 			BufferedReader lineReader = new 
> BufferedReader(new
> InputStreamReader(channel.getInputStream()));
> 			if (exec)
> 			{
> 				
> ((ChannelExec)channel).setErrStream(System.err);
> 				
> ((ChannelExec)channel).setCommand(command);
> 			}
> 			channel.connect();
> 			if (!exec)
> 			{
> 				
> os.write("PS1=\"MY_PROMPT>\"".getBytes());
> 				os.write("\n".getBytes());
> 				os.write("TERM=ansi".getBytes());
> 				os.write("\n".getBytes());
> 				os.write(command.getBytes());
> 				os.write("\n".getBytes());
> 				os.flush();
> 			}
> 			Thread.sleep(2000);
> 			while (lineReader.ready())
> 			{
> 				
> System.out.println(lineReader.readLine());
> 				if (!lineReader.ready())
> 				{
> 					Thread.sleep(2000);
> 				}
> 			}
> 	        if(channel.isClosed())
> 	        {
> 	            System.out.println("exit-status: " + 
> channel.getExitStatus());
> 	        }
> 			channel.disconnect();
> 		}
> 		catch (Exception e)
> 		{
> 			e.printStackTrace(System.out);
> 		}
> 		finally
> 		{
> 			if (session != null)
> 			{
> 				session.disconnect();
> 			}
> 		}
> 		
> 		
> 	}
> }
> 
> 
> Note, when we run just a top command it is not started in "batch"
> mode. Any idea how handle this case. If ChannelShell is the only way,
> then how to get rid of garbage (formatting) characters.
> 
> 
> Thanks & Regards,
> Amol
> 
> --------------------------------------------------------------
> -----------
> This SF.Net email is sponsored by the Moblin Your Move 
> Developer's challenge
> Build the coolest Linux based applications with Moblin SDK & 
> win great prizes
> Grand prize is a trip for two to an Open Source event 
> anywhere in the world
> http://moblin-contest.org/redirect.php?banner_id=100&url=/
> _______________________________________________
> JSch-users mailing list
> JSc...@li...
> https://lists.sourceforge.net/lists/listinfo/jsch-users
>