Bug in FTP protocol prevents changing directory :: Support Forum

shadowlmd
Joined:: 2012-01-13
Posts:: 8
Location:: St.Petersburg, Russia

Bug in FTP protocol prevents changing directory

2012-01-13 00:10

WinSCP in FTP mode fails to enter symlinked directories on some FTP servers. I am using SwiFTP on my android device and all FTP software except WinSCP works well with it. I made a debug log which clearly shows a bug in change directory code:

. 2012-01-13 02:57:39.004 Changing directory to "sdcard".
> 2012-01-13 02:57:39.004 CWD sdcard
< 2012-01-13 02:57:39.051 250 CWD successful
. 2012-01-13 02:57:39.051 Got reply 1 to the command 16
. 2012-01-13 02:57:39.051 Getting current directory name.
> 2012-01-13 02:57:39.051 PWD
< 2012-01-13 02:57:39.057 257 "mnt/sdcard"
. 2012-01-13 02:57:39.057 Got reply 1 to the command 16
. 2012-01-13 02:57:39.057 Retrieving directory listing...
> 2012-01-13 02:57:39.057 CWD /mnt/sdcard/mnt/sdcard/
< 2012-01-13 02:57:39.064 550 Can't CWD to invalid directory
. 2012-01-13 02:57:39.064 Could not retrieve directory listing
. 2012-01-13 02:57:39.065 Got reply 4 to the command 2
* 2012-01-13 02:57:39.079 (ECommand) Error listing directory 'mnt/sdcard'.
* 2012-01-13 02:57:39.079 Could not retrieve directory listing
* 2012-01-13 02:57:39.079 Can't CWD to invalid directory

I attached full log file as well.

winscplog.txt (8.15 KB)

Reply with quote

martin◆ Site Admin
Joined:: 2002-12-10
Posts:: 41,517
Location:: Prague, Czechia

Re: Bug in FTP protocol prevents changing directory

2012-01-16

Can you email me a complete log file, showing both entering regular subfolder and symlink?

Reply with quote

shadowlmd
Joined:: 2012-01-13
Posts:: 8
Location:: St.Petersburg, Russia

Re: Bug in FTP protocol prevents changing directory

2012-01-20 13:53

martin wrote:

Can you email me a complete log file, showing both entering regular subfolder and symlink?

After experimenting with different FTP servers I figured out it was not a problem with symlinks at all. Log above shows that after getting "/mnt/sdcard" as current directory, WinSCP tries to change directory to "/mnt/sdcard/mnt/sdcard" which of course doesn't exist. Same happens when it tries to enter regular directories (see new log, /system is a regular directory). That's probably something specific to SwiFTP server, because other FTP servers for Android work fine with WinSCP (apart from that one in my other bug report), but still all other FTP clients work perfectly with SwiFTP server.

Anyway, while I was making a full log as requested, after few directory changes WinSCP interface became unresponsive. I waited few minutes before closing window, no new entries were written to log file.