[rancid] #' in my login banner

Discussion:

Jan Dahl

2013-12-19 08:26:28 UTC

Maybe if we could somehow define an "ignored" string? I have a couple
of thousand switches with this in the login banner, which I won't be
allowed to change any time soon:

###### ###### # #
# # # # #
# # ###### # #
# # # # #
###### ###### #

Is it un-clever? Indeed! But it has been rolled out world wide before
I started here and now I can't use rancid.

The really weird thing for me is that somehow, terminal length and
width are set at the right time, but none of my commands are pushed
after that.

Kind regards,

Jan

Hello

I see no-one has responded with an answer to your question.
I think the reason is that code cannot deal with ">" and "#" characters
in a banner in any sane way that gives consistent results. For rancid to
function properly, it has to know what the shell prompt is exactly for a
given device, and to do that it has to parse the entire text output.
The only tool available to detect the prompt is pattern matching which
inevitably means a regex. As a perl regex this is
^[-a-zA-Z0-9]*[>#]
and that's assuming the prompt is the hostname.

In hlogin I added
-re "\[#>]+.*\[\n\r]+" {
exp_continue
}
to just pass over none prompter # and >.
Banner "#" and ">" is followed by CR or NL!

Only if the banner has a surrounding box made of > or #

One can always come up with a scheme that just happens to work for
oneself because local rules specify some exact format where you can get
a regex to work for you.

That's a lot of work though. I find it easier to just change the banner.

Works for HPs
/Peo
----------------------------------------------------------
Per-Olof Olsson Email: peo at chalmers.se
Chalmers tekniska högskola IT-service
Hörsalsvägen 5 412 96 Göteborg
Tel: 031/772 6738 Fax: 031/772 8660
----------------------------------------------------------
_______________________________________________
Rancid-discuss mailing list
Rancid-discuss at shrubbery.net
http://www.shrubbery.net/mailman/listinfo/rancid-discuss

--
Alan McKinnon
alan.mckinnon at gmail.com

Alan McKinnon

2013-12-19 09:48:57 UTC

Permalink

One possibility is to ignore any line with 2 or more #, and assume that
it's a banner. This is the command case.

Login and command prompts contain ">" or "#", but always only one.

This way, code can discard lines that are known to NOT be the prompt.
It's not 100% failproof but it is an improvement over the blind match we
currently have.

Post by Jan Dahl
Maybe if we could somehow define an "ignored" string? I have a couple
of thousand switches with this in the login banner, which I won't be
###### ###### # #
# # # # #
# # ###### # #
# # # # #
###### ###### #
Is it un-clever? Indeed! But it has been rolled out world wide before
I started here and now I can't use rancid.
The really weird thing for me is that somehow, terminal length and
width are set at the right time, but none of my commands are pushed
after that.
Kind regards,
Jan

Hello

In hlogin I added
-re "\[#>]+.*\[\n\r]+" {
exp_continue
}
to just pass over none prompter # and >.
Banner "#" and ">" is followed by CR or NL!

Only if the banner has a surrounding box made of > or #
One can always come up with a scheme that just happens to work for
oneself because local rules specify some exact format where you can get
a regex to work for you.
That's a lot of work though. I find it easier to just change the banner.

--
Alan McKinnon
***@gmail.com

heasley

2013-12-24 06:59:47 UTC

Permalink

Post by Alan McKinnon
One possibility is to ignore any line with 2 or more #, and assume that
it's a banner. This is the command case.
Login and command prompts contain ">" or "#", but always only one.
This way, code can discard lines that are known to NOT be the prompt.
It's not 100% failproof but it is an improvement over the blind match we
currently have.

Hello

In hlogin I added
-re "\[#>]+.*\[\n\r]+" {
exp_continue
}
to just pass over none prompter # and >.
Banner "#" and ">" is followed by CR or NL!

Only if the banner has a surrounding box made of > or #
One can always come up with a scheme that just happens to work for
oneself because local rules specify some exact format where you can get
a regex to work for you.
That's a lot of work though. I find it easier to just change the banner.

--
Alan McKinnon
_______________________________________________
Rancid-discuss mailing list
http://www.shrubbery.net/mailman/listinfo/rancid-discuss

This adds a 'prompt', or i suppose "initial prompt", directive to cloginrc,
so something like this could be added to cloginrc:

add prompt hostglob {^[^\n\r#]+#}

it still has an odor from my pov, but it would work for the case at hand.

Index: bin/clogin.in
===================================================================
--- bin/clogin.in (revision 2761)
+++ bin/clogin.in (working copy)
@@ -581,6 +581,7 @@
send_user "\nError: Invalid login: $router\n";
catch {close}; catch {wait}; return 1
}
+ -re "\[^\r\n]*\[\r\n]+" { exp_continue; }
}
}

@@ -763,7 +764,10 @@
}

# Default prompt.
- set prompt "(>|#| \$enable\$)"
+ set prompt [join [find prompt $router] ""]
+ if { [llength $prompt] == 0 } {
+ set prompt "(>|#| \$enable\$)"
+ }

# look for noenable option in .cloginrc
if { [find noenable $router] == "1" } {
@@ -902,9 +906,10 @@
}
# we are logged in, now figure out the full prompt
send "\r"
+ regsub -all {^(\^*)(.*)} $prompt {\2} reprompt
expect {
-re "\[\r\n]+" { exp_continue; }
- -re "^(.+\[:.])1 ($prompt)" { # stoopid extreme cmd-line numbers and
+ -re "^(.+\[:.])1 ($reprompt)" { # stoopid extreme cmd-line numbers and
# prompt based on state of config changes,
# which may have an * at the beginning.
set junk $expect_out(1,string)
@@ -913,7 +918,7 @@
set prompt ".? ?$junk\[0-9]+ $expect_out(2,string)";
set platform "extreme"
}
- -re "^.+$prompt" { set junk $expect_out(0,string);
+ -re "^.+$reprompt" { set junk $expect_out(0,string);
regsub -all "\[\]\[]" $junk {\\&} prompt;
}
}

Jan Dahl

2013-12-24 21:46:13 UTC

Permalink

I’ll try it out after the holidays and the ensuing fires that need to put out. Thanks! :)

Kind regards,
Jan

Date: Tue, 24 Dec 2013 06:59:47 +0000
Subject: Re: [rancid] #' in my login banner
Content-Type: text/plain; charset=iso-8859-1

Hello

In hlogin I added
-re "\[#>]+.*\[\n\r]+" {
exp_continue
}
to just pass over none prompter # and >.
Banner "#" and ">" is followed by CR or NL!

Only if the banner has a surrounding box made of > or #
One can always come up with a scheme that just happens to work for
oneself because local rules specify some exact format where you can get
a regex to work for you.
That's a lot of work though. I find it easier to just change the banner.

Works for HPs
/Peo
----------------------------------------------------------
Per-Olof Olsson Email: peo at chalmers.se
Chalmers tekniska h?gskola IT-service
H?rsalsv?gen 5 412 96 G?teborg
Tel: 031/772 6738 Fax: 031/772 8660
----------------------------------------------------------
_______________________________________________
Rancid-discuss mailing list
Rancid-discuss at shrubbery.net
http://www.shrubbery.net/mailman/listinfo/rancid-discuss

--
Alan McKinnon
_______________________________________________
Rancid-discuss mailing list
http://www.shrubbery.net/mailman/listinfo/rancid-discuss

This adds a 'prompt', or i suppose "initial prompt", directive to cloginrc,
add prompt hostglob {^[^\n\r#]+#}
it still has an odor from my pov, but it would work for the case at hand.
Index: bin/clogin.in
===================================================================
--- bin/clogin.in (revision 2761)
+++ bin/clogin.in (working copy)
@@ -581,6 +581,7 @@
send_user "\nError: Invalid login: $router\n";
catch {close}; catch {wait}; return 1
}
+ -re "\[^\r\n]*\[\r\n]+" { exp_continue; }
}
}
@@ -763,7 +764,10 @@
}
# Default prompt.
- set prompt "(>|#| \$enable\$)"
+ set prompt [join [find prompt $router] ""]
+ if { [llength $prompt] == 0 } {
+ set prompt "(>|#| \$enable\$)"
+ }
# look for noenable option in .cloginrc
if { [find noenable $router] == "1" } {
@@ -902,9 +906,10 @@
}
# we are logged in, now figure out the full prompt
send "\r"
+ regsub -all {^(\^*)(.*)} $prompt {\2} reprompt
expect {
-re "\[\r\n]+" { exp_continue; }
- -re "^(.+\[:.])1 ($prompt)" { # stoopid extreme cmd-line numbers and
+ -re "^(.+\[:.])1 ($reprompt)" { # stoopid extreme cmd-line numbers and
# prompt based on state of config changes,
# which may have an * at the beginning.
set junk $expect_out(1,string)
@@ -913,7 +918,7 @@
set prompt ".? ?$junk\[0-9]+ $expect_out(2,string)";
set platform "extreme"
}
- -re "^.+$prompt" { set junk $expect_out(0,string);
+ -re "^.+$reprompt" { set junk $expect_out(0,string);
regsub -all "\[\]\[]" $junk {\\&} prompt;
}
}
------------------------------