[rancid] Re: clogin bug in $prompt matching, does not work well IOS XR

[Lance Vermilion]

Have you tried adding something like the following to you .cloginrc?

add userprompt AMS-CORE-1 "RP/0/RP1/CPU0:AMS-CORE-1"

On Tue, Jan 20, 2009 at 10:33 AM, Kristian Larsson
<kristian at spritelink.net> wrote:
> Hello!
>
> I have found what I believe is a bug in clogin.
>
> When using clogin to automatically send commands
> and retrieve its output from an IOS XR device the
> prompt is not correctly parsed.
>
> When clogin first logs in, it sends a simple
> carriage return (\n) to the router to be able to
> determine the prompt. Here's an strace of that..
>
> recvfrom(3, "RP/0/RP1/CPU0:AMS-CORE-1#", 6938, 0, NULL, NULL) = 25
> write(1, "RP/0/RP1/CPU0:AMS-CORE-1#", 25) = 25
> read(0, "\r", 8177)                     = 1
> sendto(3, "\r\0", 2, 0, NULL, 0)        = 2
> recvfrom(3, "\r\n\rRP/0/RP1/CPU0:AMS-CORE-1#", 6913, 0, NULL, NULL) = 28
> write(1, "\r\n\rRP/0/RP1/CPU0:AMS-CORE-1#", 28) = 28
>
> So far, everything is fine and dandy. The router
> is obviously called ams-core-1 and it has the
> prompt RP/0/RP1/CPU0:AMS-CORE-1# which clogin
> correctly identifies.
> Here comes the next part, clogin sends 'terminal
> length 0'...
>
> read(0, "terminal length 0\r", 8176)    = 18
> sendto(3, "terminal length 0\r\0", 19, 0, NULL, 0) = 19
> recvfrom(3, "terminal\rRP/0/RP1/CPU0:AMS-CORE-1#terminal length\rRP/0/RP1/CPU0:AMS-CORE-1#terminal length 0\r\n\r", 6885, 0, NULL, NULL) = 95
>
> So it reads 'terminal length 0' from clogin, sends
> it to the CRS and then receives the output.
>
> Now, IOS XR does one thing a tad differently than
> IOS, it has command completion on the space key
> as well as on the tab key. My guess is that this
> mechanism forces the IOS XR CLI to redraw the line
> each and every time a space is entered.
> If we examine the recvfrom line
>
> recvfrom(3, "terminal\rRP/0/RP1/CPU0:AMS-CORE-1#terminal length\rRP/0/RP1/CPU0:AMS-CORE-1#terminal length 0\r\n\r", 6885, 0, NULL, NULL) = 95
>
> we see that "terminal" is first echoed back to
> the client. Then, as a space was entered, IOS XR
> does a carriage return and redraws the entire line
> starting with the prompt and filling up with
> "terminal length" and the same thing over again to
> "terminal length 0".
>
> As clogin merely looks for $prompt which is
> 'RP/0/RP1/CPU0:AMS-CORE-1#', it will get a match
> several times over and is thus unable to interpret
> the situation correctly.
>
> I've tried modifying clogin in several ways
>  - adding \n to prompt or several of the places
> where $prompt is used and so forth but so far
> without much luck. My TCL-fu is not strong enough.
>
> Could some TCL guru have a look at this? I could
> probably arrange access to an IOS XR device for
> testing.
>
> Oh, I'm running clogin version 2.3.2a9
>
> Kind regards,
>   Kristian.
>
> --
> Kristian Larsson                                        KLL-RIPE
> Network Engineer / Internet Core        Tele2 / SWIPnet [AS1257]
> +46 704 910401                                kll at spritelink.net
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