openssh bugs - Dec 2004 - [Bug 962] Data loss in interactive session on slow terminal

http://bugzilla.mindrot.org/show_bug.cgi?id=962

           Summary: Data loss in interactive session on slow terminal
           Product: Portable OpenSSH
           Version: 3.9p1
          Platform: All
        OS/Version: Linux
            Status: NEW
          Severity: normal
          Priority: P2
         Component: ssh
        AssignedTo: openssh-bugs at mindrot.org
        ReportedBy: nshmyrev at yandex.ru


Hello. I have the following system configuration:

1. Redhat Linux 3.7
2. openssh-3.9p1 with default configuration from RedHat.
3. Old d211 terminal connected to serial port at baud rate 38000
>From terminal i do 'ssh somehost'
and then 'ls -la'. Althogh my home directory has many files, the output
of ls
has only few lines. Also when I do cat on some large file it is not shown
properly.

I've wrote my version of cat which output test file but make delays between
chars. It works slowly but outputs the whole file. So I think the problem is
somewhere in rate of terminal.

Other programs like rsh works fine.



------- You are receiving this mail because: -------
You are the assignee for the bug, or are watching the assignee.

http://bugzilla.mindrot.org/show_bug.cgi?id=962





------- Additional Comments From nshmyrev at yandex.ru  2004-12-11 04:59 -------
Sorry, of course, redhat is 7.3



------- You are receiving this mail because: -------
You are the assignee for the bug, or are watching the assignee.

http://bugzilla.mindrot.org/show_bug.cgi?id=962





------- Additional Comments From dtucker at zip.com.au  2004-12-11 18:37 -------
This is unlikely to be an issue with OpenSSH, it it far more likely to be a
problem with either the serial port setup (eg flow control) or some kind of bug
in Linux's tty layer.  I suspect you have compression on, and with
compression
ssh can deliver the data faster than either the terminal or tty layer can handle
it.

If you redirect the cat to a file, eg:

ssh remoteserver cat /path/to/file > localfile

is the file complete?



------- You are receiving this mail because: -------
You are the assignee for the bug, or are watching the assignee.

http://bugzilla.mindrot.org/show_bug.cgi?id=962





------- Additional Comments From nshmyrev at yandex.ru  2004-12-13 01:28 -------
There is a lot of magic in this behavior. But since this bug is only 
reproduced in ssh, while I am working with other programs a lot and everything 
is fine, I think more about ssh. 
 
Testcases: 
 
1. without ssh 'ls -la' works fine 
2. 'ssh localhost ls -la' works fine 
3. 'ssh localhost' and then 'ls -la>output' works fine, but
then 'cat output'
is broken. 
 
The problem is only reproduced with wide and large files - there should be 
many columns and rows in the text. Small texts are displayed nicely. 



------- You are receiving this mail because: -------
You are the assignee for the bug, or are watching the assignee.

http://bugzilla.mindrot.org/show_bug.cgi?id=962





------- Additional Comments From djm at mindrot.org  2004-12-13 10:44 -------
I am guessing here, but could you try the patch attached to bug #961 ?



------- You are receiving this mail because: -------
You are the assignee for the bug, or are watching the assignee.

http://bugzilla.mindrot.org/show_bug.cgi?id=962





------- Additional Comments From dtucker at zip.com.au  2004-12-13 11:02 -------
Do you have flow control enabled on the terminall and serial port?  If not, try
enabling it.
Also, try "stty cols 80" before repeating the tests.



------- You are receiving this mail because: -------
You are the assignee for the bug, or are watching the assignee.

http://bugzilla.mindrot.org/show_bug.cgi?id=962





------- Additional Comments From nshmyrev at yandex.ru  2004-12-16 03:39 -------
I've found the reason of it - to fix this bug one should just remove in
sshtty.c
in function enter_raw_mode unset of IXON and IXOFF flags.

What is the reason you unset XON/XOFF on terminal? 





------- You are receiving this mail because: -------
You are the assignee for the bug, or are watching the assignee.

http://bugzilla.mindrot.org/show_bug.cgi?id=962





------- Additional Comments From dtucker at zip.com.au  2004-12-16 11:50 -------
I don't know, but it predates the OpenSSH project.  It was in the original
SSH
source (although the function used to be in clientloop.c).



------- You are receiving this mail because: -------
You are the assignee for the bug, or are watching the assignee.