RE: [JSch-users] Problem: too many open files with scp

[Thomas <pha...@ya...>]

A complication is that I am invoking scp to/from from within a thread.

I first created my own Scp class with two methods scpTo() and scpFrom(),
which are cut-and-pasted from the examples. Each of these two methods
creates a new Jsch object, gets a session, etc. The scpFrom() code is
shown below.

Then, each of my threads can call Scp.scpTo() and Scp.scpFrom() many
times to do downloading and then uploading for the same host/server
combination. 

If I do session.disconnect() at the end of scpTo(), I get an exception:

java.lang.RuntimeException: java.net.SocketException: Socket closed
        at com.jcraft.jsch.Session.run(Session.java:1212)
        at java.lang.Thread.run(Thread.java:567)
Caused by: java.net.SocketException: Socket closed
        at java.net.SocketInputStream.socketRead0(Native Method)
        at java.net.SocketInputStream.read(SocketInputStream.java:153)
        at com.jcraft.jsch.IO.getByte(IO.java:71)
        at com.jcraft.jsch.Session.read(Session.java:665)
        at com.jcraft.jsch.Session.run(Session.java:948)


Here is my code for scpFrom(). Can someone check if I have closed and
disconnected everything properly? 


  public void scpFrom(String remote_filename, String local_filename,
        String user, String password, String host) throws Exception
  {
        String prefix=null; 
        if(new File(local_filename).isDirectory())
        {                       
                prefix=local_filename+File.separator;
        }                       
                        
                JSch jsch=new JSch();
                Session session=jsch.getSession(user, host, 22);
                        
                // username and password will be given via UserInfo interface.
                /* UserInfo ui=new MyUserInfo(); */
                UserInfo ui = new DummyUserInfo(password);
                session.setUserInfo(ui);
                try {
                        session.connect();
                }
                catch(Exception ex) {
                        throw (new ScpConnectionException());
                }

                // exec 'scp -f remote_filename' remotely
                String command="scp -f "+remote_filename;
                Channel channel=session.openChannel("exec");
                ((ChannelExec)channel).setCommand(command);

                // get I/O streams for remote scp
                OutputStream out=channel.getOutputStream();
                InputStream in=channel.getInputStream();

                channel.connect();

                byte[] buf=new byte[_recv_buffer_size_in_bytes];

                // send '\0'
                buf[0]=0; out.write(buf, 0, 1); out.flush();

                while(true)
                {
                        int c=checkAck(in);
                        if (c!='C') {
                                break;
                        }

                        // read '0644 '
                        in.read(buf, 0, 5);

                        int filesize=0;
                        while(true) {
                                in.read(buf, 0, 1);
                                if(buf[0]==' ')break;
                                filesize=filesize*10+(buf[0]-'0');
                        }

                        String file=null;
                        for(int i=0;;i++) {
                                in.read(buf, i, 1);
                                if(buf[i]==(byte)0x0a) {
                                        file=new String(buf, 0, i);
                                        break;
                                }
                        }

                        // send '\0'
                        buf[0]=0; out.write(buf, 0, 1); out.flush();

                        // read a content of local_filename
                        FileOutputStream fos=new FileOutputStream(prefix==null
?
                                                  local_filename :
                                                  prefix+file);
                        int foo;
                        while(true) {
                                if(buf.length<filesize) foo=buf.length;
                                else foo=filesize;
                                in.read(buf, 0, foo);
                                fos.write(buf, 0, foo);
                                filesize-=foo;
                                if(filesize==0) break;
                        }
                        fos.close();
                        //fos = null;
                        byte[] tmp=new byte[1];
                        if(checkAck(in)!=0){
                                //System.exit(0);
                                throw (new ScpGeneralException());
                        }
                        // send '\0'
                        buf[0]=0; out.write(buf, 0, 1); out.flush();
                } // while
                out.close();
                in.close();
                channel.close();
                session.disconnect();
                session = null; 
                channel = null; 
                                
                //System.exit(0);
  } // scpFrom                     



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