openssh bugs - Sep 2004 - [Bug 925] Forking and crontabs do not work with ssh on NCR MP-RAS builds

http://bugzilla.mindrot.org/show_bug.cgi?id=925

           Summary: Forking and crontabs do not work with ssh on NCR MP-RAS
                    builds
           Product: Portable OpenSSH
           Version: -current
          Platform: Other
        OS/Version: other
            Status: NEW
          Severity: minor
          Priority: P2
         Component: ssh
        AssignedTo: openssh-bugs at mindrot.org
        ReportedBy: techinfo at pdmi.com


Hello.  When I attempt to run ssh with the -f (fork in background) flag or from 
a cron job I get the error: "select: No such device or address."  It
appears to
be a problem with ssh communicating with the TTY.  The OS is NCR MP-RAS SVR4 
version 3.2.  Nothing fancy in the compile (./configure / make).   I was able 
to reproduce the problem in both 3.8p1 and the current release. I will attach 
the output with the error to the bug report.  The test program I used was a 
simple shell with the command "ssh system_name ls -l" that was
scheduled as a
cron job.



------- 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=925





------- Additional Comments From techinfo at pdmi.com  2004-09-04 03:34 -------
Created an attachment (id=708)
 --> (http://bugzilla.mindrot.org/attachment.cgi?id=708&action=view)
Output in verbose mode when the error occurrs




------- 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=925





------- Additional Comments From mouring at eviladmin.org  2004-09-04 13:37
-------
Would be nice to see a "sshd -ddd" from remote side..  Also is the
remote server a MP-RAS?  Redhat?
what is it?

- Ben



------- 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=925





------- Additional Comments From techinfo at pdmi.com  2004-09-08 02:22 -------
Created an attachment (id=711)
 --> (http://bugzilla.mindrot.org/attachment.cgi?id=711&action=view)
sshd -ddd output




------- 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=925





------- Additional Comments From techinfo at pdmi.com  2004-09-08 02:31 -------
I've had the problem occur on MP-RAS and Redhat remote servers.  As a side
note
it always returns the message "select: No such device or address" but
will
sometimes complete the remote command. The majority of the time however the 
remote command doesn't appear to run.

-Steve 



------- 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=925





------- Additional Comments From dtucker at zip.com.au  2004-09-08 20:39 -------
Does ssh it give that select error when run from an interactive shell?
If you redirect ssh's stdin/stdout in the cron job, does it work?  eg
ssh -f yourserver command </dev/null >/dev/null 2>/dev/null



------- 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=925





------- Additional Comments From techinfo at pdmi.com  2004-09-08 23:25 -------
Running from an interactive shell (without the -f option) works fine.  It only 
errors when running from a crontab or using the -f option interactivly.  
Redirecting stdin/stdout/stderr  still will generate the "select"
error.  I ran
the following which redirected everything and still got the error:

ssh -f myserver "ls </dev/null >/dev/null 2>/dev/null"
>/tmp/test.out 2>&1
</dev/null

In the test.out file I had the "select" error.

I also ran variations of the above command. All of them returned the select 
error.





------- 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=925





------- Additional Comments From dtucker at zip.com.au  2004-09-09 10:33 -------
Does redirecting the output to /dev/null in the interactive shell cause the
select errors?

Also, does "lsof" work on that platform?  If so, comparing the output
from lsof
for an interactive login and the cron job may prove enlightening...



------- 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=925





------- Additional Comments From techinfo at pdmi.com  2004-09-09 23:12 -------
I do not have the lsof program on this platform. 

Running the command in an interactive shell and redirecting to >/dev/null
DOES
cause the select error to happen.   The command:
ssh myserver ls >/dev/null
will generate a select error.



------- 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=925





------- Additional Comments From dtucker at zip.com.au  2004-09-11 23:44 -------
Also try the patch in bug #830, and if that's it please close this bug as a
duplicate of #830.



------- 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=925





------- Additional Comments From techinfo at pdmi.com  2004-09-14 02:45 -------
I applied the patch from 830 and it partially fixed the problem.  

Interactively the -f option now works, as long as you don't redirect the ssh
output to /dev/null (prior to the patch -f failed every time).  

I still get the select() error when I redirect stdout to /dev/null without the -
f option.   If the output is redirected to a file I don't get a select() 
error.  It only happens when redirected to /dev/null.

I did find that if the remote command that is executed doesn't return any 
output the select() error will not occur.





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