| /* |
| * 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.nio.charset.StandardCharsets; |
| import java.time.Duration; |
| import java.util.Collection; |
| import java.util.Objects; |
| |
| import org.apache.commons.lang3.time.DurationUtils; |
| import org.apache.commons.logging.Log; |
| import org.apache.commons.logging.LogFactory; |
| 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.provider.AbstractFileName; |
| import org.apache.commons.vfs2.provider.AbstractFileSystem; |
| import org.apache.commons.vfs2.provider.GenericFileName; |
| |
| 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 Log LOG = LogFactory.getLog(SftpFileSystem.class); |
| |
| private static final int UNIDENTIFED = -1; |
| |
| private static final int SLEEP_MILLIS = 100; |
| |
| private static final int EXEC_BUFFER_SIZE = 128; |
| |
| private static final long LAST_MOD_TIME_ACCURACY = 1000L; |
| |
| /** |
| * Session; never null. |
| * <p> |
| * DCL pattern requires that the ivar be volatile. |
| * </p> |
| */ |
| private volatile Session session; |
| |
| private volatile ChannelSftp idleChannel; |
| |
| private final Duration connectTimeout; |
| |
| /** |
| * Cache for the user ID (-1 when not set) |
| * <p> |
| * DCL pattern requires that the ivar be volatile. |
| * </p> |
| */ |
| private volatile int uid = UNIDENTIFED; |
| |
| /** |
| * Cache for the user groups ids (null when not set) |
| * <p> |
| * DCL pattern requires that the ivar be volatile. |
| * </p> |
| */ |
| private volatile int[] groupsIds; |
| |
| /** |
| * Some SFTP-only servers disable the exec channel. When exec is disabled, things like getUId() will always fail. |
| */ |
| private final boolean execDisabled; |
| |
| protected SftpFileSystem(final GenericFileName rootName, final Session session, |
| final FileSystemOptions fileSystemOptions) { |
| super(rootName, null, fileSystemOptions); |
| this.session = Objects.requireNonNull(session, "session"); |
| this.connectTimeout = SftpFileSystemConfigBuilder.getInstance() |
| .getConnectTimeout(fileSystemOptions); |
| |
| if (SftpFileSystemConfigBuilder.getInstance().isDisableDetectExecChannel(fileSystemOptions)) { |
| this.execDisabled = true; |
| } else { |
| this.execDisabled = detectExecDisabled(); |
| } |
| } |
| |
| @Override |
| protected void doCloseCommunicationLink() { |
| if (idleChannel != null) { |
| synchronized (this) { |
| if (idleChannel != null) { |
| idleChannel.disconnect(); |
| idleChannel = null; |
| } |
| } |
| } |
| |
| if (session != null) { |
| session.disconnect(); |
| } |
| } |
| |
| /** |
| * 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 { |
| try { |
| // Use the pooled channel, or create a new one |
| ChannelSftp channel = null; |
| if (idleChannel != null) { |
| synchronized (this) { |
| if (idleChannel != null) { |
| channel = idleChannel; |
| idleChannel = null; |
| } |
| } |
| } |
| |
| if (channel == null) { |
| channel = (ChannelSftp) getSession().openChannel("sftp"); |
| channel.connect(DurationUtils.toMillisInt(connectTimeout)); |
| 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 Session getSession() throws FileSystemException { |
| if (!this.session.isConnected()) { |
| synchronized (this) { |
| if (!this.session.isConnected()) { |
| doCloseCommunicationLink(); |
| this.session = SftpFileProvider.createSession((GenericFileName) getRootName(), |
| getFileSystemOptions()); |
| } |
| } |
| } |
| return this.session; |
| } |
| |
| /** |
| * Returns a channel to the pool. |
| * |
| * @param channelSftp the SFTP channel. |
| */ |
| protected void putChannel(final ChannelSftp channelSftp) { |
| if (idleChannel == null) { |
| synchronized (this) { |
| if (idleChannel == null) { |
| // put back the channel only if it is still connected |
| if (channelSftp.isConnected() && !channelSftp.isClosed()) { |
| idleChannel = channelSftp; |
| } |
| } else { |
| channelSftp.disconnect(); |
| } |
| } |
| } else { |
| channelSftp.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) { |
| synchronized (this) { |
| // DCL pattern requires that the ivar be volatile. |
| 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; |
| } |
| |
| /** |
| * Gets 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 == UNIDENTIFED) { |
| synchronized (this) { |
| if (uid == UNIDENTIFED) { |
| 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 + ")"); |
| } |
| final String uidString = output.toString().trim(); |
| try { |
| uid = Integer.parseInt(uidString); |
| } catch (final NumberFormatException e) { |
| LOG.debug("Cannot convert UID to integer: '" + uidString + "'", e); |
| } |
| } |
| } |
| } |
| return uid; |
| } |
| |
| /** |
| * Executes 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 { |
| final ChannelExec channel = (ChannelExec) getSession().openChannel("exec"); |
| try { |
| channel.setCommand(command); |
| channel.setInputStream(null); |
| try (final InputStreamReader stream = new InputStreamReader(channel.getInputStream(), StandardCharsets.UTF_8)) { |
| channel.setErrStream(System.err, true); |
| channel.connect(DurationUtils.toMillisInt(connectTimeout)); |
| |
| // 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); |
| } |
| } |
| |
| // 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? |
| } |
| } |
| } finally { |
| channel.disconnect(); |
| } |
| return channel.getExitStatus(); |
| } |
| |
| /** |
| * @return Whether the exec channel is disabled. |
| * @see SftpFileSystem#execDisabled |
| */ |
| public boolean isExecDisabled() { |
| return execDisabled; |
| } |
| |
| /** |
| * Some SFTP-only servers disable the exec channel. |
| * |
| * Attempt to detect this by calling getUid. |
| */ |
| private boolean detectExecDisabled() { |
| try { |
| return getUId() == UNIDENTIFED; |
| } catch(final JSchException | IOException e) { |
| LOG.debug("Cannot get UID, assuming no exec channel is present", e); |
| return true; |
| } |
| } |
| |
| } |