How to Set Root Directory in Apache Mina Sshd Server in Java

Question

I use Apache Mina Sshd API to start up a local SFTP server in java.In SFTP client i use Jcraft jsch API to create my SFTP client.I successfully start up a server.The problem is that i want to write some unit test cases to check whether client can put some files into server's root directory. Currently my SFTP server doesn't have any root directory.So i would like to know that is there is any approach to set server's root directory.

Eg: C:\sftp How can i set this path as my server root directory.so then client can read and write files to it every time connect with the server.Thank you.

public class SftpServerStarter {
	
	private SshServer sshd;
	private final static Logger logger = LoggerFactory.getLogger(SftpServerStarter.class);
	
	public void start(){
		
		
		sshd = SshServer.setUpDefaultServer();
		sshd.setPort(22);
		sshd.setHost("localhost");
		
        sshd.setPasswordAuthenticator(new MyPasswordAuthenticator());
        sshd.setPublickeyAuthenticator(new MyPublickeyAuthenticator());
        sshd.setKeyPairProvider(new SimpleGeneratorHostKeyProvider());
        sshd.setSubsystemFactories(Arrays.<NamedFactory<Command>>asList(new SftpSubsystem.Factory()));
        sshd.setCommandFactory(new ScpCommandFactory());
        
        

        try {
        	logger.info("Starting ...");
			sshd.start();
			logger.info("Started");
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
			logger.info("Can not Start Server");
		}
	}
	
}

Answer 1

In Default it takes the root path from System property called user.dir

Inorder to change this, you can override getVirtualUserDir() in NativeFileSystemView and return your path.

    sshd.setFileSystemFactory(new NativeFileSystemFactory() {
        @Override
        public FileSystemView createFileSystemView(final Session session) {
            return new NativeFileSystemView(session.getUsername(), false) {
                @Override
                public String getVirtualUserDir() {
                    return  "C:\\MyRoot";
                }
            };
        };
    });

Answer 2

You can also follow following link to know about how to set root directory in Apache Mina sshd SFTP server with different sshd-core version.

<dependency>
        <groupId>org.apache.sshd</groupId>
        <artifactId>sshd-core</artifactId>
        <version>0.10.0</version>
    </dependency>

into

<dependency>
        <groupId>org.apache.sshd</groupId>
        <artifactId>sshd-core</artifactId>
        <version>0.14.0</version>
    </dependency>

How to override getVirtualUserDir() in Apache Mina sshd-core version 0.14.0

Answer 3

In more recent sshd versions you can use org.apache.sshd.common.file.virtualfs.VirtualFileSystemFactory and supply it to the SshServer instance via method setFileSystemFactory.