public class RExecClient extends SocketClient
As with virtually all of the client classes in org.apache.commons.net, this class derives from SocketClient, inheriting its connection methods. The way to
use RExecClient is to first connect to the server, call the rexec()
method, and then fetch the connection's input, output, and optionally
error streams. Interaction with the remote command is controlled entirely through the I/O streams. Once you have finished processing the streams, you should
invoke disconnect()
to clean up properly.
By default the standard output and standard error streams of the remote process are transmitted over the same connection, readable from the input stream
returned by getInputStream()
. However, it is possible to tell the rexecd daemon to return the standard error stream over a separate
connection, readable from the input stream returned by getErrorStream()
. You can specify that a separate connection should be created
for standard error by setting the boolean separateErrorStream
parameter of rexec()
to true
. The standard input
of the remote process can be written to through the output stream returned by getOutputSream()
.
SocketClient
,
RCommandClient
,
RLoginClient
Modifier and Type | Field and Description |
---|---|
protected InputStream |
_errorStream_
If a separate error stream is requested,
_errorStream_ will point to an InputStream from which the standard error of the remote process can
be read (after a call to rexec()). |
static int |
DEFAULT_PORT
The default rexec port.
|
protected static char |
NULL_CHAR |
_defaultPort_, _hostname_, _input_, _output_, _serverSocketFactory_, _socket_, _socketFactory_, _timeout_, connectTimeout, NETASCII_EOL
Constructor and Description |
---|
RExecClient()
The default RExecClient constructor.
|
Modifier and Type | Method and Description |
---|---|
void |
disconnect()
Disconnects from the server, closing all associated open sockets and streams.
|
InputStream |
getErrorStream()
Returns the InputStream from which the standard error of the remote process can be read if a separate error stream is requested from the server.
|
InputStream |
getInputStream()
Returns the InputStream from which the standard output of the remote process can be read.
|
OutputStream |
getOutputStream()
Returns the OutputStream through which the standard input of the remote process can be written.
|
boolean |
isRemoteVerificationEnabled()
Return whether or not verification of the remote host providing a separate error stream is enabled.
|
void |
rexec(String username,
String password,
String command)
Same as
rexec(username, password, command, false); |
void |
rexec(String username,
String password,
String command,
boolean separateErrorStream)
Remotely executes a command through the rexecd daemon on the server to which the RExecClient is connected.
|
void |
setRemoteVerificationEnabled(boolean enable)
Enable or disable verification that the remote host connecting to create a separate error stream is the same as the host to which the standard out stream
is connected.
|
_connectAction_, addProtocolCommandListener, applySocketAttributes, connect, connect, connect, connect, connect, connect, createCommandSupport, fireCommandSent, fireReplyReceived, getCharset, getCharsetName, getCommandSupport, getConnectTimeout, getDefaultPort, getDefaultTimeout, getKeepAlive, getLocalAddress, getLocalPort, getProxy, getReceiveBufferSize, getRemoteAddress, getRemotePort, getSendBufferSize, getServerSocketFactory, getSoLinger, getSoTimeout, getTcpNoDelay, isAvailable, isConnected, removeProtocolCommandListener, setCharset, setConnectTimeout, setDefaultPort, setDefaultTimeout, setKeepAlive, setProxy, setReceiveBufferSize, setSendBufferSize, setServerSocketFactory, setSocketFactory, setSoLinger, setSoTimeout, setTcpNoDelay, verifyRemote
protected static final char NULL_CHAR
public static final int DEFAULT_PORT
protected InputStream _errorStream_
_errorStream_
will point to an InputStream from which the standard error of the remote process can
be read (after a call to rexec()). Otherwise, _errorStream_
will be null.public RExecClient()
DEFAULT_PORT
.public void disconnect() throws IOException
disconnect
in class SocketClient
IOException
- If there an error occurs while disconnecting.public InputStream getErrorStream()
public InputStream getInputStream()
public OutputStream getOutputStream()
public final boolean isRemoteVerificationEnabled()
public void rexec(String username, String password, String command) throws IOException
rexec(username, password, command, false);
username
- the user namepassword
- the passwordcommand
- the command to runIOException
- if an error occurspublic void rexec(String username, String password, String command, boolean separateErrorStream) throws IOException
getInputStream()
. Disconnecting from the server or closing
the process streams before reaching end of file will not necessarily terminate the remote process.
If a separate error stream is requested, the remote server will connect to a local socket opened by RExecClient, providing an independent stream through
which standard error will be transmitted. RExecClient will do a simple security check when it accepts a connection for this error stream. If the
connection does not originate from the remote server, an IOException will be thrown. This serves as a simple protection against possible hijacking of the
error stream by an attacker monitoring the rexec() negotiation. You may disable this behavior with setRemoteVerificationEnabled()
.
username
- The account name on the server through which to execute the command.password
- The plain text password of the user account.command
- The command, including any arguments, to execute.separateErrorStream
- True if you would like the standard error to be transmitted through a different stream than standard output. False if not.IOException
- If the rexec() attempt fails. The exception will contain a message indicating the nature of the failure.public final void setRemoteVerificationEnabled(boolean enable)
enable
- True to enable verification, false to disable verification.Copyright © 2001–2022 The Apache Software Foundation. All rights reserved.