RE: [Syslog] RE: byte-counting vs special character

"Rainer Gerhards" <rgerhards@hq.adiscon.com> Thu, 17 August 2006 01:19 UTC

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Subject: RE: [Syslog] RE: byte-counting vs special character
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Date: Thu, 17 Aug 2006 03:18:56 +0200
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Thread-Topic: [Syslog] RE: byte-counting vs special character
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From: Rainer Gerhards <rgerhards@hq.adiscon.com>
To: Carson Gaspar <carson@taltos.org>
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Caspar - since when does legacy code do escaping? (Even if I've
overlooked it, we might use a different escape character...)

Anyhow - the "whishy-washy" blew the WGs work last year. Ignoring legacy
compatibility trashed roughly a year of work. I don't want to see this
happen again. I'll post a more elaborate message on last years failure
of the syslog WG due to ignoring backward compatibility as soon as I am
able to do so...

Rainer 

> -----Original Message-----
> From: Carson Gaspar [mailto:carson@taltos.org] 
> Sent: Wednesday, August 16, 2006 6:21 PM
> To: syslog@ietf.org
> Subject: RE: [Syslog] RE: byte-counting vs special character
> 
> --On Thursday, August 17, 2006 2:08 AM +0200 Rainer Gerhards 
> <rgerhards@hq.adiscon.com> wrote:
> 
> > Legacy code does not contain LF in messages. It is advised that
> > new-style syslog also does not contain control characters 
> (though it now
> > is allowed).
> 
> Legacy code _will_ emit doubled escape characters (unless the escape 
> character selected is forbidden in legacy code). They will then be 
> mis-interpreted by new code.
> 
> New code _will_ double the escape character when sending it 
> to legacy code, 
> mangling the message.
> 
> You can't have it both ways. Either you forbid LF and use it as a EOM 
> marker and get backwards compatibility, or you allow LF (via whatever 
> mechanism, escaping or octet counting are equivalent) and 
> break backwards 
> compatibility. Statements that "doubled escape characters are 
> unlikely in 
> legacy messages" are bogus. Either they are _impossible_, or 
> they will 
> happen eventually.
> 
> If you want to bow at the alter of the installed base, forbid LF in 
> messages. If not, then octet counting is technically superior. This 
> wishy-washy middle ground is just a terrible idea.
> 
> -- 
> Carson
> 
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