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https://issues.apache.org/jira/browse/VFS-437?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13468041#comment-13468041
 ] 

Dan Tran commented on VFS-437:
------------------------------

Hi Gary, 

Dennis, Jason, and I work on the same team.  Other way to reproduce this issue 
is 

  1. use anonymous account on a linux ftp server 
  2. On your anonymous workspace create a symlink ( Vol1 to /Vol1 ). The ftp'ls 
command should show

     ftp> ls -al
     200 PORT command successful. Consider using PASV.
     150 Here comes the directory listing.
     drwxr-xr-x    4 0        0            4096 Oct 02 19:02 .
     drwxr-xr-x    4 0        0            4096 Oct 02 19:02 ..
     lrwxrwxrwx    1 0        0               5 Oct 02 19:02 Vol1 -> /Vol1
     drwxr-xr-x    2 0        0            4096 Sep 03  2009 pub
     -rw-r--r--    1 0        0             224 Nov 09  2004 welcome.msg
     226 Directory send OK.
     ftp:385 bytes received in 0.00Seconds 385000.00Kbytes/sec.


  3. Use vfs-maven-plugin to issue the following command ( provided that you 
have access to codehaus's snapshot repository


     mvn vfs:list -DsourceId=ftp.anonymous -Dsource=ftp://your.ftp.host/Vol1


This is very edgecase, however, it crashes our server application.  

                
> [FTP] Program crashes when StackOverFlow Exception happens from pulling a 
> softlinked directory that link to the directory that has the same name one 
> level above 
> -----------------------------------------------------------------------------------------------------------------------------------------------------------------
>
>                 Key: VFS-437
>                 URL: https://issues.apache.org/jira/browse/VFS-437
>             Project: Commons VFS
>          Issue Type: Bug
>    Affects Versions: 2.0
>         Environment: java version "1.7.0_02"
> Java(TM) SE Runtime Environment (build 1.7.0_02-b13)
> Java HotSpot(TM) 64-Bit Server VM (build 22.0-b10, mixed mode)
> Linux version 2.6.18-238.el5 (mockbu...@builder10.centos.org) (gcc version 
> 4.1.2 20080704 (Red Hat 4.1.2-48)) #1 SMP Thu Jan 13 15:51:15 EST 2011
>            Reporter: Jason
>            Priority: Blocker
>             Fix For: 2.1
>
>
> With the setting below, StackOverFlow exceptions occur and server crashes
> set the builder.setUserDirlsRoot (opt, true)
> Attept to pull with:
> ftp://root:password@ip:/Vol1
> Vol directory has the following info
> lrwxrwxrwx  1 root root        5 Oct  5  2007 Vol1 -> /Vol1
> When it tries to look for the parent of the Vol1, it goes back to the same 
> Vol1, which causes a infinite loop that eventually creates stackoverflow 
> exception.
> The problem is inside the doGetType() method in FtpFileObject
>     @Override
>     protected FileType doGetType()
>         throws Exception
>     {
>         // VFS-210
>         synchronized (getFileSystem())
>         {
>             if (this.fileInfo == null)
>             {
>                 getInfo(false);
>             }
>             if (this.fileInfo == UNKNOWN)
>             {
>                 return FileType.IMAGINARY;
>             }
>             else if (this.fileInfo.isDirectory())
>             {
>                 return FileType.FOLDER;
>             }
>             else if (this.fileInfo.isFile())
>             {
>                 return FileType.FILE;
>             }
>             else if (this.fileInfo.isSymbolicLink())
>             {
>                 return getLinkDestination().getType();
>             }
>         }
>         throw new FileSystemException("vfs.provider.ftp/get-type.error", 
> getName());
>     }
> It will keep hitting the "else if (this.fileinfo.isSymbolicLink())" condition 
> and the fileinfo displayed is always the Vol1 under root directory.
> Exception is shown below
> java.lang.StackOverflowError
>       at org.apache.commons.net.ftp.FTPFile.isDirectory(FTPFile.java:116)
>       at 
> org.apache.commons.vfs2.provider.ftp.FtpFileObject.doGetType(FtpFileObject.java:334)
>       at 
> org.apache.commons.vfs2.provider.AbstractFileObject.getType(AbstractFileObject.java:496)
>       at 
> org.apache.commons.vfs2.provider.ftp.FtpFileObject.doGetType(FtpFileObject.java:344)
>       at 
> org.apache.commons.vfs2.provider.AbstractFileObject.getType(AbstractFileObject.java:496)
>       at 
> org.apache.commons.vfs2.provider.ftp.FtpFileObject.doGetType(FtpFileObject.java:344)
>       at 
> org.apache.commons.vfs2.provider.AbstractFileObject.getType(AbstractFileObject.java:496)
>       at 
> org.apache.commons.vfs2.provider.ftp.FtpFileObject.doGetType(FtpFileObject.java:344)
>       at 
> org.apache.commons.vfs2.provider.AbstractFileObject.getType(AbstractFileObject.java:496)
>       at 
> org.apache.commons.vfs2.provider.ftp.FtpFileObject.doGetType(FtpFileObject.java:344)
>       at 
> org.apache.commons.vfs2.provider.AbstractFileObject.getType(AbstractFileObject.java:496)
>       at 
> org.apache.commons.vfs2.provider.ftp.FtpFileObject.doGetType(FtpFileObject.java:344)
>       at 
> org.apache.commons.vfs2.provider.AbstractFileObject.getType(AbstractFileObject.java:496)
>       at 
> org.apache.commons.vfs2.provider.ftp.FtpFileObject.doGetType(FtpFileObject.java:344)
>       at 
> org.apache.commons.vfs2.provider.AbstractFileObject.getType(AbstractFileObject.java:496)
>       at 
> org.apache.commons.vfs2.provider.ftp.FtpFileObject.doGetType(FtpFileObject.java:344)
>       at 
> org.apache.commons.vfs2.provider.AbstractFileObject.getType(AbstractFileObject.java:496)
>       at 
> org.apache.commons.vfs2.provider.ftp.FtpFileObject.doGetType(FtpFileObject.java:344)
>       at 
> org.apache.commons.vfs2.provider.AbstractFileObject.getType(AbstractFileObject.java:496)
>       at 
> org.apache.commons.vfs2.provider.ftp.FtpFileObject.doGetType(FtpFileObject.java:344)
>       at 
> org.apache.commons.vfs2.provider.AbstractFileObject.getType(AbstractFileObject.java:496)
>       at 
> org.apache.commons.vfs2.provider.ftp.FtpFileObject.doGetType(FtpFileObject.java:344)
>       at 
> org.apache.commons.vfs2.provider.AbstractFileObject.getType(AbstractFileObject.java:496)
>       at 
> org.apache.commons.vfs2.provider.ftp.FtpFileObject.doGetType(FtpFileObject.java:344)
>       at 
> org.apache.commons.vfs2.provider.AbstractFileObject.getType(AbstractFileObject.java:496)
>       at 
> org.apache.commons.vfs2.provider.ftp.FtpFileObject.doGetType(FtpFileObject.java:344)

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