core/src/main/java/org/apache/commons/vfs2/provider/sftp/SftpFileSystem.java - commons-vfs - Git at Google

 /*
  * Licensed to the Apache Software Foundation (ASF) under one or more
  * contributor license agreements.  See the NOTICE file distributed with
  * this work for additional information regarding copyright ownership.
  * The ASF licenses this file to You under the Apache License, Version 2.0
  * (the "License"); you may not use this file except in compliance with
  * the License.  You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
 package org.apache.commons.vfs2.provider.sftp;

 import java.io.IOException;
 import java.io.InputStreamReader;
 import java.util.Collection;

 import org.apache.commons.vfs2.Capability;
 import org.apache.commons.vfs2.FileObject;
 import org.apache.commons.vfs2.FileSystemException;
 import org.apache.commons.vfs2.FileSystemOptions;
 import org.apache.commons.vfs2.UserAuthenticationData;
 import org.apache.commons.vfs2.provider.AbstractFileName;
 import org.apache.commons.vfs2.provider.AbstractFileSystem;
 import org.apache.commons.vfs2.provider.GenericFileName;
 import org.apache.commons.vfs2.util.UserAuthenticatorUtils;

 import com.jcraft.jsch.ChannelExec;
 import com.jcraft.jsch.ChannelSftp;
 import com.jcraft.jsch.JSchException;
 import com.jcraft.jsch.Session;
 import com.jcraft.jsch.SftpException;

 /**
  * Represents the files on an SFTP server.
  */
 public class SftpFileSystem
     extends AbstractFileSystem
 {
     private static final int SLEEP_MILLIS = 100;

     private static final int EXEC_BUFFER_SIZE = 128;

     private static final long LAST_MOD_TIME_ACCURACY = 1000L;

     private Session session;

     // private final JSch jSch;

     private ChannelSftp idleChannel;

     /**
      * Cache for the user ID (-1 when not set)
      */
     private int uid = -1;

     /**
      * Cache for the user groups ids (null when not set)
      */
     private int[] groupsIds;

     protected SftpFileSystem(final GenericFileName rootName,
                              final Session session,
                              final FileSystemOptions fileSystemOptions)
     {
         super(rootName, null, fileSystemOptions);
         this.session = session;
     }

     @Override
     protected void doCloseCommunicationLink()
     {
         if (idleChannel != null)
         {
             idleChannel.disconnect();
             idleChannel = null;
         }

         if (session != null)
         {
             session.disconnect();
             session = null;
         }
     }

     /**
      * Returns an SFTP channel to the server.
      *
      * @return new or reused channel, never null.
      * @throws FileSystemException if a session cannot be created.
      * @throws IOException if an I/O error is detected.
      */
     protected ChannelSftp getChannel() throws IOException
     {
         ensureSession();
         try
         {
             // Use the pooled channel, or create a new one
             final ChannelSftp channel;
             if (idleChannel != null)
             {
                 channel = idleChannel;
                 idleChannel = null;
             }
             else
             {
                 channel = (ChannelSftp) session.openChannel("sftp");
                 channel.connect();
                 final Boolean userDirIsRoot =
                     SftpFileSystemConfigBuilder.getInstance().getUserDirIsRoot(getFileSystemOptions());
                 final String workingDirectory = getRootName().getPath();
                 if (workingDirectory != null && (userDirIsRoot == null || !userDirIsRoot.booleanValue()))
                 {
                     try
                     {
                         channel.cd(workingDirectory);
                     }
                     catch (final SftpException e)
                     {
                         throw new FileSystemException("vfs.provider.sftp/change-work-directory.error",
                             workingDirectory, e);
                     }
                 }
             }

             final String fileNameEncoding = SftpFileSystemConfigBuilder.getInstance().getFileNameEncoding(
                     getFileSystemOptions());

             if (fileNameEncoding != null)
             {
                 try
                 {
                     channel.setFilenameEncoding(fileNameEncoding);
                 }
                 catch (final SftpException e)
                 {
                     throw new FileSystemException("vfs.provider.sftp/filename-encoding.error", fileNameEncoding);
                 }
             }
             return channel;
         }
         catch (final JSchException e)
         {
             throw new FileSystemException("vfs.provider.sftp/connect.error", getRootName(), e);
         }
     }

     /**
      * Ensures that the session link is established.
      *
      * @throws FileSystemException if a session cannot be created.
      */
     private void ensureSession() throws FileSystemException
     {
         if (this.session == null || !this.session.isConnected())
         {
             doCloseCommunicationLink();

             // channel closed. e.g. by freeUnusedResources, but now we need it again
             Session session;
             UserAuthenticationData authData = null;
             try
             {
                 final GenericFileName rootName = (GenericFileName) getRootName();

                 authData = UserAuthenticatorUtils.authenticate(getFileSystemOptions(),
                         SftpFileProvider.AUTHENTICATOR_TYPES);

                 session = SftpClientFactory.createConnection(
                         rootName.getHostName(),
                         rootName.getPort(),
                         UserAuthenticatorUtils.getData(authData, UserAuthenticationData.USERNAME,
                                 UserAuthenticatorUtils.toChar(rootName.getUserName())),
                         UserAuthenticatorUtils.getData(authData, UserAuthenticationData.PASSWORD,
                                 UserAuthenticatorUtils.toChar(rootName.getPassword())),
                         getFileSystemOptions());
             }
             catch (final Exception e)
             {
                 throw new FileSystemException("vfs.provider.sftp/connect.error", getRootName(), e);
             }
             finally
             {
                 UserAuthenticatorUtils.cleanup(authData);
             }
             this.session = session;
         }
     }

     /**
      * Returns a channel to the pool.
      *
      * @param channel the used channel.
      */
     protected void putChannel(final ChannelSftp channel)
     {
         if (idleChannel == null)
         {
             // put back the channel only if it is still connected
             if (channel.isConnected() && !channel.isClosed())
             {
                 idleChannel = channel;
             }
         }
         else
         {
             channel.disconnect();
         }
     }

     /**
      * Adds the capabilities of this file system.
      */
     @Override
     protected void addCapabilities(final Collection<Capability> caps)
     {
         caps.addAll(SftpFileProvider.capabilities);
     }

     /**
      * Creates a file object.  This method is called only if the requested
      * file is not cached.
      */
     @Override
     protected FileObject createFile(final AbstractFileName name)
         throws FileSystemException
     {
         return new SftpFileObject(name, this);
     }

     /**
      * Last modification time is only an int and in seconds, thus can be off by 999.
      *
      * @return 1000
      */
     @Override
     public double getLastModTimeAccuracy()
     {
         return LAST_MOD_TIME_ACCURACY;
     }

     /**
      * Gets the (numeric) group IDs.
      *
      * @return the (numeric) group IDs.
      * @throws JSchException If a problem occurs while retrieving the group IDs.
      * @throws IOException if an I/O error is detected.
      * @since 2.1
      */
     public int[] getGroupsIds() throws JSchException, IOException
     {
         if (groupsIds == null)
         {
             final StringBuilder output = new StringBuilder();
             final int code = executeCommand("id -G", output);
             if (code != 0)
             {
                 throw new JSchException("Could not get the groups id of the current user (error code: " + code + ")");
             }

             // Retrieve the different groups
             final String[] groups = output.toString().trim().split("\\s+");

             final int[] groupsIds = new int[groups.length];
             for (int i = 0; i < groups.length; i++)
             {
                 groupsIds[i] = Integer.parseInt(groups[i]);
             }

             this.groupsIds = groupsIds;
         }
         return groupsIds;
     }

     /**
      * Get the (numeric) group IDs.
      *
      * @return The numeric user ID
      * @throws JSchException If a problem occurs while retrieving the group ID.
      * @throws IOException if an I/O error is detected.
      * @since 2.1
      */
     public int getUId() throws JSchException, IOException
     {
         if (uid < 0)
         {
             final StringBuilder output = new StringBuilder();
             final int code = executeCommand("id -u", output);
             if (code != 0)
             {
                 throw new FileSystemException("Could not get the user id of the current user (error code: " + code
                         + ")");
             }
             uid = Integer.parseInt(output.toString().trim());
         }
         return uid;
     }

     /**
      * Execute a command and returns the (standard) output through a StringBuilder.
      *
      * @param command The command
      * @param output The output
      * @return The exit code of the command
      * @throws JSchException if a JSch error is detected.
      * @throws FileSystemException if a session cannot be created.
      * @throws IOException if an I/O error is detected.
      */
     private int executeCommand(final String command, final StringBuilder output) throws JSchException, IOException
     {
         ensureSession();
         final ChannelExec channel = (ChannelExec) session.openChannel("exec");

         channel.setCommand(command);
         channel.setInputStream(null);
         final InputStreamReader stream = new InputStreamReader(channel.getInputStream());
         channel.setErrStream(System.err, true);
         channel.connect();

         // Read the stream
         final char[] buffer = new char[EXEC_BUFFER_SIZE];
         int read;
         while ((read = stream.read(buffer, 0, buffer.length)) >= 0)
         {
             output.append(buffer, 0, read);
         }
         stream.close();

         // Wait until the command finishes (should not be long since we read the output stream)
         while (!channel.isClosed())
         {
             try
             {
                 Thread.sleep(SLEEP_MILLIS);
             }
             catch (final Exception ee)
             {
                 // TODO: swallow exception, really?
             }
         }
         channel.disconnect();
         return channel.getExitStatus();
     }
 }
	/*
	* Licensed to the Apache Software Foundation (ASF) under one or more
	* contributor license agreements. See the NOTICE file distributed with
	* this work for additional information regarding copyright ownership.
	* The ASF licenses this file to You under the Apache License, Version 2.0
	* (the "License"); you may not use this file except in compliance with
	* the License. You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/
	package org.apache.commons.vfs2.provider.sftp;

	import java.io.IOException;
	import java.io.InputStreamReader;
	import java.util.Collection;

	import org.apache.commons.vfs2.Capability;
	import org.apache.commons.vfs2.FileObject;
	import org.apache.commons.vfs2.FileSystemException;
	import org.apache.commons.vfs2.FileSystemOptions;
	import org.apache.commons.vfs2.UserAuthenticationData;
	import org.apache.commons.vfs2.provider.AbstractFileName;
	import org.apache.commons.vfs2.provider.AbstractFileSystem;
	import org.apache.commons.vfs2.provider.GenericFileName;
	import org.apache.commons.vfs2.util.UserAuthenticatorUtils;

	import com.jcraft.jsch.ChannelExec;
	import com.jcraft.jsch.ChannelSftp;
	import com.jcraft.jsch.JSchException;
	import com.jcraft.jsch.Session;
	import com.jcraft.jsch.SftpException;

	/**
	* Represents the files on an SFTP server.
	*/
	public class SftpFileSystem
	extends AbstractFileSystem
	{
	private static final int SLEEP_MILLIS = 100;

	private static final int EXEC_BUFFER_SIZE = 128;

	private static final long LAST_MOD_TIME_ACCURACY = 1000L;

	private Session session;

	// private final JSch jSch;

	private ChannelSftp idleChannel;

	/**
	* Cache for the user ID (-1 when not set)
	*/
	private int uid = -1;

	/**
	* Cache for the user groups ids (null when not set)
	*/
	private int[] groupsIds;

	protected SftpFileSystem(final GenericFileName rootName,
	final Session session,
	final FileSystemOptions fileSystemOptions)
	{
	super(rootName, null, fileSystemOptions);
	this.session = session;
	}

	@Override
	protected void doCloseCommunicationLink()
	{
	if (idleChannel != null)
	{
	idleChannel.disconnect();
	idleChannel = null;
	}

	if (session != null)
	{
	session.disconnect();
	session = null;
	}
	}

	/**
	* Returns an SFTP channel to the server.
	*
	* @return new or reused channel, never null.
	* @throws FileSystemException if a session cannot be created.
	* @throws IOException if an I/O error is detected.
	*/
	protected ChannelSftp getChannel() throws IOException
	{
	ensureSession();
	try
	{
	// Use the pooled channel, or create a new one
	final ChannelSftp channel;
	if (idleChannel != null)
	{
	channel = idleChannel;
	idleChannel = null;
	}
	else
	{
	channel = (ChannelSftp) session.openChannel("sftp");
	channel.connect();
	final Boolean userDirIsRoot =
	SftpFileSystemConfigBuilder.getInstance().getUserDirIsRoot(getFileSystemOptions());
	final String workingDirectory = getRootName().getPath();
	if (workingDirectory != null && (userDirIsRoot == null \|\| !userDirIsRoot.booleanValue()))
	{
	try
	{
	channel.cd(workingDirectory);
	}
	catch (final SftpException e)
	{
	throw new FileSystemException("vfs.provider.sftp/change-work-directory.error",
	workingDirectory, e);
	}
	}
	}

	final String fileNameEncoding = SftpFileSystemConfigBuilder.getInstance().getFileNameEncoding(
	getFileSystemOptions());

	if (fileNameEncoding != null)
	{
	try
	{
	channel.setFilenameEncoding(fileNameEncoding);
	}
	catch (final SftpException e)
	{
	throw new FileSystemException("vfs.provider.sftp/filename-encoding.error", fileNameEncoding);
	}
	}
	return channel;
	}
	catch (final JSchException e)
	{
	throw new FileSystemException("vfs.provider.sftp/connect.error", getRootName(), e);
	}
	}

	/**
	* Ensures that the session link is established.
	*
	* @throws FileSystemException if a session cannot be created.
	*/
	private void ensureSession() throws FileSystemException
	{
	if (this.session == null \|\| !this.session.isConnected())
	{
	doCloseCommunicationLink();

	// channel closed. e.g. by freeUnusedResources, but now we need it again
	Session session;
	UserAuthenticationData authData = null;
	try
	{
	final GenericFileName rootName = (GenericFileName) getRootName();

	authData = UserAuthenticatorUtils.authenticate(getFileSystemOptions(),
	SftpFileProvider.AUTHENTICATOR_TYPES);

	session = SftpClientFactory.createConnection(
	rootName.getHostName(),
	rootName.getPort(),
	UserAuthenticatorUtils.getData(authData, UserAuthenticationData.USERNAME,
	UserAuthenticatorUtils.toChar(rootName.getUserName())),
	UserAuthenticatorUtils.getData(authData, UserAuthenticationData.PASSWORD,
	UserAuthenticatorUtils.toChar(rootName.getPassword())),
	getFileSystemOptions());
	}
	catch (final Exception e)
	{
	throw new FileSystemException("vfs.provider.sftp/connect.error", getRootName(), e);
	}
	finally
	{
	UserAuthenticatorUtils.cleanup(authData);
	}
	this.session = session;
	}
	}

	/**
	* Returns a channel to the pool.
	*
	* @param channel the used channel.
	*/
	protected void putChannel(final ChannelSftp channel)
	{
	if (idleChannel == null)
	{
	// put back the channel only if it is still connected
	if (channel.isConnected() && !channel.isClosed())
	{
	idleChannel = channel;
	}
	}
	else
	{
	channel.disconnect();
	}
	}

	/**
	* Adds the capabilities of this file system.
	*/
	@Override
	protected void addCapabilities(final Collection<Capability> caps)
	{
	caps.addAll(SftpFileProvider.capabilities);
	}

	/**
	* Creates a file object. This method is called only if the requested
	* file is not cached.
	*/
	@Override
	protected FileObject createFile(final AbstractFileName name)
	throws FileSystemException
	{
	return new SftpFileObject(name, this);
	}

	/**
	* Last modification time is only an int and in seconds, thus can be off by 999.
	*
	* @return 1000
	*/
	@Override
	public double getLastModTimeAccuracy()
	{
	return LAST_MOD_TIME_ACCURACY;
	}

	/**
	* Gets the (numeric) group IDs.
	*
	* @return the (numeric) group IDs.
	* @throws JSchException If a problem occurs while retrieving the group IDs.
	* @throws IOException if an I/O error is detected.
	* @since 2.1
	*/
	public int[] getGroupsIds() throws JSchException, IOException
	{
	if (groupsIds == null)
	{
	final StringBuilder output = new StringBuilder();
	final int code = executeCommand("id -G", output);
	if (code != 0)
	{
	throw new JSchException("Could not get the groups id of the current user (error code: " + code + ")");
	}

	// Retrieve the different groups
	final String[] groups = output.toString().trim().split("\\s+");

	final int[] groupsIds = new int[groups.length];
	for (int i = 0; i < groups.length; i++)
	{
	groupsIds[i] = Integer.parseInt(groups[i]);
	}

	this.groupsIds = groupsIds;
	}
	return groupsIds;
	}

	/**
	* Get the (numeric) group IDs.
	*
	* @return The numeric user ID
	* @throws JSchException If a problem occurs while retrieving the group ID.
	* @throws IOException if an I/O error is detected.
	* @since 2.1
	*/
	public int getUId() throws JSchException, IOException
	{
	if (uid < 0)
	{
	final StringBuilder output = new StringBuilder();
	final int code = executeCommand("id -u", output);
	if (code != 0)
	{
	throw new FileSystemException("Could not get the user id of the current user (error code: " + code
	+ ")");
	}
	uid = Integer.parseInt(output.toString().trim());
	}
	return uid;
	}

	/**
	* Execute a command and returns the (standard) output through a StringBuilder.
	*
	* @param command The command
	* @param output The output
	* @return The exit code of the command
	* @throws JSchException if a JSch error is detected.
	* @throws FileSystemException if a session cannot be created.
	* @throws IOException if an I/O error is detected.
	*/
	private int executeCommand(final String command, final StringBuilder output) throws JSchException, IOException
	{
	ensureSession();
	final ChannelExec channel = (ChannelExec) session.openChannel("exec");

	channel.setCommand(command);
	channel.setInputStream(null);
	final InputStreamReader stream = new InputStreamReader(channel.getInputStream());
	channel.setErrStream(System.err, true);
	channel.connect();

	// Read the stream
	final char[] buffer = new char[EXEC_BUFFER_SIZE];
	int read;
	while ((read = stream.read(buffer, 0, buffer.length)) >= 0)
	{
	output.append(buffer, 0, read);
	}
	stream.close();

	// Wait until the command finishes (should not be long since we read the output stream)
	while (!channel.isClosed())
	{
	try
	{
	Thread.sleep(SLEEP_MILLIS);
	}
	catch (final Exception ee)
	{
	// TODO: swallow exception, really?
	}
	}
	channel.disconnect();
	return channel.getExitStatus();
	}
	}