public abstract class SessionChannel extends Channel<SshServerContext> implements IdleStateListener
This class provides an abstract session, it handles all the requests defined in the SSH Connection protocol for a session channel and passes the request to the concrete implementation through its abstract methods.
When creating a session implementation your processStdinData(byte[])
will receive data from the client and process as session input. To send
stdout data for your session you should use the
sendStdoutData(byte[])
method and any sdterr output should be send
using sendStderrData(byte[])
method.
As the server uses an asynchronous framework expensive blocking operations SHOULD NOT be performed within your session as this will cause a deadlock on the server.
The basic process of establishing a session is this
sendExitStatus(int)
.Channel.QueuedData
Modifier and Type | Field and Description |
---|---|
protected int |
maximumWindowSpace |
protected int |
minimumWindowSpace |
static int |
SSH_EXTENDED_DATA_STDERR |
connection, localwindow, localWindowLock
Constructor and Description |
---|
SessionChannel() |
SessionChannel(int maximumPacket,
int maximumWindowSpace) |
Modifier and Type | Method and Description |
---|---|
protected abstract boolean |
allocatePseudoTerminal(String term,
int cols,
int rows,
int width,
int height,
byte[] modes)
If the client requests a pseudo terminal for the session this method will
be invoked before the shell, exec or subsystem is started.
|
protected abstract void |
changeWindowDimensions(int cols,
int rows,
int width,
int height)
When the window (terminal) size changes on the client side, it MAY send
notification in which case this method will be invoked to notify the
session that a change has occurred.
|
protected byte[] |
createChannel()
set the max window space as a multiple of the minimum window space.
|
protected void |
evaluateWindowSpace(int remaining)
Called to evaluate the window space available.
|
protected abstract boolean |
executeCommand(String cmd)
Invoked when the user wants to execute a command
|
void |
haltIncomingData() |
boolean |
idle()
Process an idle event.
|
boolean |
isIncomingDataHalted() |
protected void |
onChannelClosing()
Called when the channel is closing.
|
protected void |
onChannelData(byte[] data)
Called when data arrives on the channel.
|
protected void |
onChannelFree()
Free the session and its resources.
|
protected void |
onChannelOpen()
Called once the channel has been opened.
|
protected void |
onChannelOpenConfirmation()
Called when the channel is confirmed as open
|
protected void |
onChannelRequest(String type,
boolean wantreply,
byte[] requestdata)
Process session requests and invoke the relevant abstract methods of this
class to handle the requests.
|
protected void |
onExtendedData(byte[] data,
int type)
Called when extended data arrives on the channel - for a session channel
this would not normally be called.
|
protected void |
onRemoteEOF()
The remote side has reported EOF so no more data will be received.
|
protected abstract void |
onSessionOpen()
Called once the session is open and data can be sent/received.
|
protected byte[] |
openChannel(byte[] data)
Called when the channel is being opened.
|
protected abstract void |
processSignal(String signal)
A signal can be delivered to the process by the client.
|
protected abstract void |
processStdinData(byte[] data)
Data has arrived on the session's stdin stream.
|
void |
resumeIncomingData() |
void |
sendExitStatus(int exitcode)
When a command or shell exits its possible to send the client the exit
code of the process.
|
void |
sendStderrData(byte[] data)
Send stderr data to the remote client.
|
void |
sendStderrData(byte[] data,
int off,
int len)
Sends stderr data to the remote client.
|
void |
sendStdoutData(byte[] data)
Sends stdout data to the remote client
|
void |
sendStdoutData(byte[] data,
int off,
int len)
Sends stdout data to the remote client.
|
protected abstract boolean |
setEnvironmentVariable(String name,
String value)
If the client requests that an environment variable be set this method
will be invoked.
|
protected abstract boolean |
startShell()
Invoked when the user wants to start a shell.
|
addEventListener, addInputListener, addOutputListener, canClose, clearIdleState, close, getChannelType, getConnection, getConnectionProtocol, getContext, getLocalId, getLocalPacket, getLocalWindow, getQueueSize, getRemoteId, getRemotePacket, getRemoteWindow, getSessionIdentifier, isClosed, isClosing, isEOF, isLocalEOF, isOpen, isRemoteEOF, onChannelClosed, onChannelOpenFailure, onLocalEOF, onRemoteClose, onWindowAdjust, processChannelRequestResponse, queueSize, registerExtendedData, resetIdleState, sendChannelData, sendChannelData, sendChannelData, sendChannelData, sendChannelDataAndBlock, sendChannelRequest, sendEOF, sendExtendedData, sendExtendedData, sendRequestResponse, sendWindowAdjust
protected int maximumWindowSpace
protected int minimumWindowSpace
public static final int SSH_EXTENDED_DATA_STDERR
public SessionChannel()
public SessionChannel(int maximumPacket, int maximumWindowSpace)
protected final byte[] createChannel() throws IOException
createChannel
in class Channel<SshServerContext>
minSizeMultiple
- IOException
protected abstract boolean allocatePseudoTerminal(String term, int cols, int rows, int width, int height, byte[] modes)
term
- cols
- rows
- width
- height
- modes
- protected abstract void changeWindowDimensions(int cols, int rows, int width, int height)
cols
- rows
- width
- height
- protected abstract void processSignal(String signal)
signal
- protected abstract boolean setEnvironmentVariable(String name, String value)
name
- value
- protected abstract boolean startShell()
protected abstract boolean executeCommand(String cmd)
cmd
- protected abstract void processStdinData(byte[] data)
data
- protected abstract void onSessionOpen()
protected void onChannelOpen()
onChannelOpen
in class Channel<SshServerContext>
public boolean idle()
IdleStateListener
idle
in interface IdleStateListener
protected void onChannelRequest(String type, boolean wantreply, byte[] requestdata)
onChannelRequest
in class Channel<SshServerContext>
type
- Stringwantreply
- booleanrequestdata
- byte[]protected void onChannelOpenConfirmation()
onChannelOpenConfirmation
in class Channel<SshServerContext>
protected void onRemoteEOF()
onRemoteEOF
in class Channel<SshServerContext>
protected void onChannelFree()
onChannelFree
in class Channel<SshServerContext>
protected void onChannelClosing()
onChannelClosing
in class Channel<SshServerContext>
protected void onChannelData(byte[] data)
onChannelData
in class Channel<SshServerContext>
data
- byte[]protected void onExtendedData(byte[] data, int type)
onExtendedData
in class Channel<SshServerContext>
data
- byte[]type
- intpublic void sendStdoutData(byte[] data, int off, int len)
data
- off
- len
- public void sendStdoutData(byte[] data)
data
- public void sendStderrData(byte[] data, int off, int len)
data
- off
- len
- public void sendStderrData(byte[] data)
data
- public void sendExitStatus(int exitcode)
exitcode
- protected final void evaluateWindowSpace(int remaining)
Channel
evaluateWindowSpace
in class Channel<SshServerContext>
public void haltIncomingData()
public void resumeIncomingData()
protected final byte[] openChannel(byte[] data) throws WriteOperationRequest, ChannelOpenException
Channel
openChannel
in class Channel<SshServerContext>
WriteOperationRequest
ChannelOpenException
public boolean isIncomingDataHalted()
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