openssh unix dev - Nov 2000 - Pseudo-tty allocation and -T option

Hello,

I've set up a cron job to use ssh with a remote forced command to delete the
contents of a directory. System A has the cron job and uses a specific key
for system B. No command as such is specified since the key on system B
specifies 'command=/bin/rm -rf ...'. However, I am getting error
messages
back from the cron system (or rather from ssh) about it not allocating a tty
since there is no controlling terminal - obviously not since the job is run
through cron:

  Pseudo-terminal will not be allocated because stdin is not a terminal.

I have tried using the -T option and specifying no_pty in the
key options on system B, but I still get the error message. The man page for
ssh says:
 
     -T      Disable pseudo-tty allocation (protocol version 2 only).

We are only using protocol 2; openssh 2.3.0p1. So is '-T' not working
correctly, am I doing something wrong or is openssh correct in that it will
always print out the message if used via cron? If the latter then how can I
'remove' the message since the output gets mailed back to the user (in
this
case the postmasters). I have thought about using:

    ssh .... 2>&1 | egrep -v "^Pseudo-terminal will not be"

which seems to work but seems a bit messy. Using '-q' to ssh makes no
difference either. My understanding from the man page is that -T should
prevent it attempting to allocate a tty.

Thanks for any help,

John.

------------------------------------------------------------------------
John Horne, University of Plymouth, UK           Tel: +44 (0)1752 233914
E-mail: jhorne at plymouth.ac.uk
PGP key available from public key servers

try the patch or
	ssh host dummy
instead of
	ssh host
-markus

Index: ssh.c
==================================================================RCS file:
/home/markus/cvs/ssh/ssh.c,v
retrieving revision 1.74
diff -u -r1.74 ssh.c
--- ssh.c	2000/11/23 21:03:47	1.74
+++ ssh.c	2000/11/30 07:00:38
@@ -504,15 +504,15 @@
 	if (buffer_len(&command) == 0)
 		tty_flag = 1;
 
+	/* Force no tty*/
+	if (no_tty_flag)
+		tty_flag = 0;
 	/* Do not allocate a tty if stdin is not a tty. */
 	if (!isatty(fileno(stdin))) {
 		if (tty_flag)
 			fprintf(stderr, "Pseudo-terminal will not be allocated because stdin is
not a terminal.\n");
 		tty_flag = 0;
 	}
-	/* force */
-	if (no_tty_flag)
-		tty_flag = 0;
 
 	/* Get user data. */
 	pw = getpwuid(original_real_uid);



On Wed, Nov 29, 2000 at 03:23:00PM -0000, John Horne
wrote:
> Hello,
> 
> I've set up a cron job to use ssh with a remote forced command to
delete the
> contents of a directory. System A has the cron job and uses a specific key
> for system B. No command as such is specified since the key on system B
> specifies 'command=/bin/rm -rf ...'. However, I am getting error
messages
> back from the cron system (or rather from ssh) about it not allocating a
tty
> since there is no controlling terminal - obviously not since the job is run
> through cron:
> 
>   Pseudo-terminal will not be allocated because stdin is not a terminal.
> 
> I have tried using the -T option and specifying no_pty in the
> key options on system B, but I still get the error message. The man page
for
> ssh says:
>  
>      -T      Disable pseudo-tty allocation (protocol version 2 only).
> 
> We are only using protocol 2; openssh 2.3.0p1. So is '-T' not
working
> correctly, am I doing something wrong or is openssh correct in that it will
> always print out the message if used via cron? If the latter then how can I
> 'remove' the message since the output gets mailed back to the user
(in this
> case the postmasters). I have thought about using:
> 
>     ssh .... 2>&1 | egrep -v "^Pseudo-terminal will not
be"
> 
> which seems to work but seems a bit messy. Using '-q' to ssh makes
no
> difference either. My understanding from the man page is that -T should
> prevent it attempting to allocate a tty.
> 
> Thanks for any help,
> 
> John.
> 
> ------------------------------------------------------------------------
> John Horne, University of Plymouth, UK           Tel: +44 (0)1752 233914
> E-mail: jhorne at plymouth.ac.uk
> PGP key available from public key servers
>