com.sshtools.ssh2

Class Ssh2Session

java.lang.Object

com.sshtools.ssh.message.SshAbstractChannel

com.sshtools.ssh2.Ssh2Channel

com.sshtools.ssh2.Ssh2Session

All Implemented Interfaces:

SshChannel, SshIO, SshSession

public class Ssh2Session
extends Ssh2Channel
implements SshSession

This class implements the SSH2 session channel, unlike SSH1 multiple sessions can be opened on the same SSH connection.

Author:

Lee David Painter

Field Summary

Fields inherited from class com.sshtools.ssh2.Ssh2Channel

SESSION_CHANNEL

Fields inherited from class com.sshtools.ssh.message.SshAbstractChannel

CHANNEL_CLOSED, CHANNEL_OPEN, CHANNEL_UNINITIALIZED, channelid, manager, ms, state

Fields inherited from interface com.sshtools.ssh.SshSession

EXITCODE_NOT_RECEIVED

Constructor Summary

Constructors

Constructor and Description
Ssh2Session(int windowsize, int packetsize, Ssh2Client client) Construct a session channel.

Method Summary

Methods

Modifier and Type	Method and Description
void	changeTerminalDimensions(int cols, int rows, int width, int height) Change the dimensions of the terminal window.
protected void	channelRequest(String requesttype, boolean wantreply, byte[] requestdata) This overidden method handles the "exit-status", "exit-signal" and "xon-xoff" channel requests.
protected void	checkCloseStatus(boolean remoteClosed)
boolean	executeCommand(String cmd) Execute a command.
boolean	executeCommand(String cmd, String charset) Execute a command.
int	exitCode() Return the exit code of the process once complete.
SshClient	getClient() Get the client that created this session.
String	getExitSignalInfo() Get the exit signal information, may be an empty string.
InputStream	getStderrInputStream() Get an InputStream to read the process stderr.
boolean	hasExitSignal() Determine whether the remote process was signalled.
boolean	isFlowControlEnabled() On many systems it is possible to determine whether a pseudo-terminal is using control-S/ control-Q flow control.
protected void	processExtendedData(int typecode, int length, SshChannelMessage msg) Called when extended data arrives.
boolean	requestPseudoTerminal(String term, int cols, int rows, int width, int height) The remote process may require a pseudo terminal.
boolean	requestPseudoTerminal(String term, int cols, int rows, int width, int height, byte[] modes) The remote process may require a pseudo terminal.
boolean	requestPseudoTerminal(String term, int cols, int rows, int width, int height, PseudoTerminalModes terminalModes) The remote process may require a pseudo terminal.
boolean	setEnvironmentVariable(String name, String value) The SSH2 session supports the setting of environments variables however in our experiance no server to date allows unconditional setting of variables.
void	signal(String signal) Send a signal to the remote process.
boolean	startShell() Start the users default shell.
boolean	startSubsystem(String subsystem) SSH2 supports special subsystems that are identified by a name rather than a command string, an example of an SSH2 subsystem is SFTP.

Methods inherited from class com.sshtools.ssh2.Ssh2Channel

addChannelEventListener, channelEOF, close, create, createExtendedDataStream, equals, getInputStream, getMessageStore, getName, getOutputStream, getStickyMessageIds, idle, isSendKeepAliveOnIdle, open, open, processChannelMessage, processStandardData, processStandardData, sendRequest, sendRequest, setAutoConsumeInput, setSendKeepAliveOnIdle

Methods inherited from class com.sshtools.ssh.message.SshAbstractChannel

getChannelId, getMessageRouter, init, isClosed

Methods inherited from class java.lang.Object

clone, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface com.sshtools.ssh.SshSession

close, getInputStream, getOutputStream, isClosed

Methods inherited from interface com.sshtools.ssh.SshChannel

addChannelEventListener, getChannelId, getMessageRouter, setAutoConsumeInput

Constructor Detail

Ssh2Session

public Ssh2Session(int windowsize,
           int packetsize,
           Ssh2Client client)

Construct a session channel.

Parameters:

windowsize - the initial/maximum window space available

packetsize - the maximum packet size

Method Detail

getClient

public SshClient getClient()

Description copied from interface: SshSession

Get the client that created this session.

Specified by:

getClient in interface SshSession

Returns:

SshClient

processExtendedData

protected void processExtendedData(int typecode,
                       int length,
                       SshChannelMessage msg)
                            throws SshException

Description copied from class: Ssh2Channel

Called when extended data arrives. This method fires the com.sshtools.ssh.ChannelEventListener#extendedDataReceived(com.sshtools.ssh.Channel, byte[], int, int, int) event so to maintain code compatibility always call the super method in any overidden method.

Overrides:

processExtendedData in class Ssh2Channel

Parameters:

typecode - the type of extended data

Throws:

SshException

getStderrInputStream

public InputStream getStderrInputStream()

Description copied from interface: SshSession

Get an InputStream to read the process stderr.

Specified by:

getStderrInputStream in interface SshSession

Returns:

the sessions stderr InputStream

requestPseudoTerminal

public boolean requestPseudoTerminal(String term,
                            int cols,
                            int rows,
                            int width,
                            int height)
                              throws SshException

Description copied from interface: SshSession

The remote process may require a pseudo terminal. Call this method before executing a command or starting a shell.

Specified by:

requestPseudoTerminal in interface SshSession

Parameters:

term - the terminal type e.g "vt100"

cols - the number of columns

rows - the number of rows

width - the width of the terminal (informational only, can be zero)

height - the height of the terminal (informational only, can be zero)

Returns:

true if the pty was allocated, otherwise false

Throws:

SshException

requestPseudoTerminal

public boolean requestPseudoTerminal(String term,
                            int cols,
                            int rows,
                            int width,
                            int height,
                            PseudoTerminalModes terminalModes)
                              throws SshException

Description copied from interface: SshSession

The remote process may require a pseudo terminal. Call this method before executing a command or starting a shell.

Specified by:

requestPseudoTerminal in interface SshSession

Parameters:

term - the terminal type e.g "vt100"

cols - the number of columns

rows - the number of rows

width - the width of the terminal (informational only, can be zero)

height - the height of the terminal (informational only, can be zero)

terminalModes - the known terminal modes

Returns:

true if the pty was allocated, otherwise false

Throws:

SshException

requestPseudoTerminal

public boolean requestPseudoTerminal(String term,
                            int cols,
                            int rows,
                            int width,
                            int height,
                            byte[] modes)
                              throws SshException

Description copied from interface: SshSession

The remote process may require a pseudo terminal. Call this method before executing a command or starting a shell.

Specified by:

requestPseudoTerminal in interface SshSession

Parameters:

term - the terminal type e.g "vt100"

cols - the number of columns

rows - the number of rows

width - the width of the terminal (informational only, can be zero)

height - the height of the terminal (informational only, can be zero)

modes - an array of encoded terminal modes as described in the SSH protocol specifications.

Returns:

true if the pty was allocated, otherwise false

Throws:

SshException

startShell

public boolean startShell()
                   throws SshException

Description copied from interface: SshSession

Start the users default shell.

Specified by:

startShell in interface SshSession

Returns:

true if the shell was started, otherwise false

Throws:

SshException

executeCommand

public boolean executeCommand(String cmd)
                       throws SshException

Description copied from interface: SshSession

Execute a command. An important note to remember is that this does not execute a shell command. You cannot for instance issue the command executeCommand("dir")" on the Windows Operating system as this is a shell command, instead use "cmd.exe /C dir". This method executes a binary executable and so should be used to execute any program other than the users shell. Calls to this method should only be used to execute commands that are indedependent, such as "mkdir /home/david/newfolder".

Specified by:

executeCommand in interface SshSession

Returns:

true if the command was accepted, otherwise false. This may not return false if the command is incorrect, it should only be used as an indication that the command was accepted and that the server will attempt to execute it.

Throws:

SshException

executeCommand

public boolean executeCommand(String cmd,
                     String charset)
                       throws SshException

Description copied from interface: SshSession

Execute a command. An important note to remember is that this does not execute a shell command. You cannot for instance issue the command executeCommand("dir")" on the Windows Operating system as this is a shell command, instead use "cmd.exe /C dir". This method executes a binary executable and so should be used to execute any program other than the users shell. Calls to this method should only be used to execute commands that are indedependent, such as "mkdir /home/david/newfolder".

Specified by:

executeCommand in interface SshSession

Returns:

true if the command was accepted, otherwise false. This may not return false if the command is incorrect, it should only be used as an indication that the command was accepted and that the server will attempt to execute it.

Throws:

SshException

startSubsystem

public boolean startSubsystem(String subsystem)
                       throws SshException

SSH2 supports special subsystems that are identified by a name rather than a command string, an example of an SSH2 subsystem is SFTP.

Parameters:

subsystem - the name of the subsystem, for example "sftp"

Returns:

true if the subsystem was started, otherwise false

Throws:

SshException

setEnvironmentVariable

public boolean setEnvironmentVariable(String name,
                             String value)
                               throws SshException

The SSH2 session supports the setting of environments variables however in our experiance no server to date allows unconditional setting of variables. This method should be called before the command is started.

Throws:

SshException

changeTerminalDimensions

public void changeTerminalDimensions(int cols,
                            int rows,
                            int width,
                            int height)
                              throws SshException

Description copied from interface: SshSession

Change the dimensions of the terminal window. This method should be called when the session is active and the user or application changes the size of the terminal window.

Specified by:

changeTerminalDimensions in interface SshSession

Throws:

SshException

isFlowControlEnabled

public boolean isFlowControlEnabled()

On many systems it is possible to determine whether a pseudo-terminal is using control-S/ control-Q flow control. When flow control is allowed it is often esirable to do the flow control at the client end to speed up responses to user requests. If this method returns true the client is allowed to do flow control using control-S and control-Q

Returns:

boolean

signal

public void signal(String signal)
            throws SshException

Send a signal to the remote process. A signal can be delivered to the remote process using this method, some systems may not implement signals. The signal name should be one of the following values:

 ABRT
 ALRM
 FPE
 HUP
 ILL
 INT
 KILL
 PIPE
 QUIT
 SEGV
 TERM
 USR1
 USR2
 

Parameters:

signal -

Throws:

IOException

SshException

channelRequest

protected void channelRequest(String requesttype,
                  boolean wantreply,
                  byte[] requestdata)
                       throws SshException

This overidden method handles the "exit-status", "exit-signal" and "xon-xoff" channel requests.

Overrides:

channelRequest in class Ssh2Channel

Parameters:

requesttype - the name of the request

wantreply - specifies whether the remote side requires a success/failure message

requestdata - the request data

Throws:

SshException

exitCode

public int exitCode()

Description copied from interface: SshSession

Return the exit code of the process once complete. Call this after the session has been closed to obtain the exit code of the process. It MAY or MAY NOT be sent by the server. If the exit code was not received this method will return EXITCODE_NOT_RECEIVED.

Specified by:

exitCode in interface SshSession

Returns:

the exit code value or SshSession.EXITCODE_NOT_RECEIVED

checkCloseStatus

protected void checkCloseStatus(boolean remoteClosed)

Overrides:

checkCloseStatus in class Ssh2Channel

hasExitSignal

public boolean hasExitSignal()

Determine whether the remote process was signalled.

Returns:

true if a signal was received, otherwise false

getExitSignalInfo

public String getExitSignalInfo()

Get the exit signal information, may be an empty string.

Returns:

String