Skaros Ilias Skaros Ilias - 1 month ago 6
Java Question

sftp java client keeps sshd process running on remote machine

I am using the jcraft library in order to send files from one server to an other one, using scp. The code is like this

public class Scp {
String DestinationHost;//host IP
String DestinationUserName;//username
String DestinationPassword;//password
String DestinationPublicKeyFile;//public key-if any
String DestinationDirectory;//where to save on remote
String SourceFile;
/*
setters-getters
*/
public void send() throws SftpException, FileNotFoundException, JSchException{
JSch jsch = new JSch();
Session session = null;
session = jsch.getSession(DestinationUserName,DestinationHost,22);
jsch.addIdentity(getDestinationPublicKeyFile(),getDestinationPassword());

session.setConfig("StrictHostKeyChecking", "no");
session.connect();

ChannelSftp channel = null;

//try to connect
channel = (ChannelSftp)session.openChannel("sftp");
channel.connect(30000);
channel.connect();

File localFile = new File(getSourceFile());
File remoteFile=new File(getDestinationDirectory());
channel.cd(remoteFile.getParent());

channel.put(new FileInputStream(localFile),//the source file
remoteFile.getParentFile().getName());//the destination name(not the path)

channel.disconnect();
session.disconnect();
}
}


This is been called from an other java class, several times, each of which is creating a new object, like so

Scp scp=new Scp();

scp.setDestinationHost(CopyDestHost);
scp.setDestinationPassword(CopyDestPassword);
scp.setDestinationPublicKeyFile(CopyDestKey);
scp.setDestinationUserName(CopyDestUser);
scp.setSourceFile(temp.getAbsolutePath());
scp.setDestinationDirectory(filepath);

stream.flush();
stream.close();
scp.send();


Since i am clossing the connections using
channel.disconnect();
and
session.disconnect();
why do I see a huge list of
sshd
processes running on my remote machine hours after the connection is closed? for example

root 13251 863 0 11:54 ? 00:00:00 sshd: skaros [priv]
user 13300 13251 0 11:54 ? 00:00:00 sshd: skaros@notty
skaros 13301 13300 0 11:54 ? 00:00:00 /usr/lib/openssh/sftp-server
root 14885 863 0 10:35 ? 00:00:00 sshd: skaros [priv]
skaros 14986 14885 0 10:35 ? 00:00:00 sshd: skaros@notty
skaros 14987 14986 0 10:35 ? 00:00:00 /usr/lib/openssh/sftp-server


Is that a problem? should I kill them manually? Do I just leave them like that?

Answer

It turned out to be a "bug". This post solved it with this

  while (channel.getExitStatus() == -1){
       try{Thread.sleep(1000);}catch(Exception e){System.out.println(e);}
  }
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