Problems with cygwin, "expect" and ssh
I have found some interesting behavior regarding the cygwin expect/ssh
problem. I used the little expect script
That Corinna created. It seemed to not see the prompt for the password
from the spawned ssh, so it just timed out. But, when I redirect the
stderr to /dev/null, it behaves correctly. Perhaps ssh is spitting some
spurious bytes to stderr that are causing the expect pattern to not
match:
GOOD:
[EMAIL PROTECTED] ~
$ ./sshtest 2>/dev/null
spawn ssh -t 10.65.16.41
Before expect for assword:
[EMAIL PROTECTED]'s password: Found assword:
Before send of password
After send of password
Last login: Thu Jan 01 1970 00:00:00 from
[==]
Use of this system is explicitly limited to employees...
-
BAD:
[EMAIL PROTECTED] ~
$ ./sshtest
spawn ssh -t
Before expect for assword:
[EMAIL PROTECTED]'s password: Spawning failed
[EMAIL PROTECTED] ~
---
SCRIPT:
cat sshtest
#!/usr/bin/expect -f
set timeout 10
spawn ssh -t
puts "Before expect for assword:"
expect {
"*assword:" {
puts "Found assword:"
sleep 2
}
default {
send_user "Spawning failed\n"
exit
}
}
puts "Before send of password"
send "xxx\r"
puts "After send of password"
expect {
-re ".*\\$.* " { }
default {
send_user "Sending password failed\n"
exit
}
}
send "ls\n"
expect {
-re ".*\\$.* " { }
default {
send_user "Sending ls failed\n"
exit
}
}
send "exit\n"
expect {
-re ".*Connection to mycygwinbox closed.*" { }
default {
send_user "Sending exit failed\n"
exit
}
}
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Re: Problems with cygwin, "expect" and ssh
On Mon, Oct 13, 2003 at 06:47:12PM -0500, Greenup, Greenup wrote:
>Enter "expect", which ships with a little script for changing your
> password (even on multiple systems en-mass). Nice. Except... it doesn't
> seem to work with ssh... Near as I can tell from my googling, a problem of
> openssh reading the tty directly, rather than allocating a tty. True?
> False? What about other things?; messing with the CYGWIN variable, adding
> "tty" in there was not helpful, nor was adding "-t" to ssh. Any other
> ideas? I don't want to use telnet... "console telnet" is nice, and will get
> the job done, but it's not a secure answer.
I'm not sure what you did wrong but apparently you did. I just tried
the following crude script:
= SNIP =
#!/usr/bin/expect -f
set timeout 10
spawn ssh mycygwinbox
expect {
"[EMAIL PROTECTED]'s password: " { }
default {
send_user "Spawning failed\n"
exit
}
}
send "mypassword\n"
expect {
-re ".*\\$.* " { }
default {
send_user "Sending password failed\n"
exit
}
}
send "ls\n"
expect {
-re ".*\\$.* " { }
default {
send_user "Sending ls failed\n"
exit
}
}
send "exit\n"
expect {
-re ".*Connection to mycygwinbox closed.*" { }
default {
send_user "Sending exit failed\n"
exit
}
}
= SNAP =
and it worked perfectly fine, from a Windows console window as well as from
a ssh session itself. The first two regexps are expecting my prompt, btw.
Corinna
--
Corinna Vinschen Please, send mails regarding Cygwin to
Cygwin Developermailto:[EMAIL PROTECTED]
Red Hat, Inc.
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Problems with cygwin, "expect" and ssh
I've done a fair bit of searching on the net (6+hours of googling), but can't find a solution, or a complete "No, there's no way to work around that" to this problem: I have to log into a large number of systems, and on some sets (such as "all devboxes") I like to keep my password the same, for convenience. (and to keep my memory sane; I really need to keep this list from going "hundreds") Ssh is my tool of preference, though I could use telnet. Unfortunately, the Higher Powers have declared private key authentication illegal so far (I'm working on them), so I am left with typing this stuff by hand. All of that, I can more or less deal with, until *Password*Day*. Remember "hundreds"? Obviously, I don't log into all of these boxes during a given month, but I really have to be able to get to them when the time comes. Enter "expect", which ships with a little script for changing your password (even on multiple systems en-mass). Nice. Except... it doesn't seem to work with ssh... Near as I can tell from my googling, a problem of openssh reading the tty directly, rather than allocating a tty. True? False? What about other things?; messing with the CYGWIN variable, adding "tty" in there was not helpful, nor was adding "-t" to ssh. Any other ideas? I don't want to use telnet... "console telnet" is nice, and will get the job done, but it's not a secure answer. -greenup -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/
