[OpenAFS] Re: [OpenAFS-devel] exposing RPC code<->name mappings via rxgen extension, a library, and a new utility

Tue, 5 May 2009 10:12:49 +0200 (CEST)

  This message is in MIME format.  The first part should be readable text,
  while the remaining parts are likely unreadable without MIME-aware tools.

--579669762-1509803715-1241511170=:21930
Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed

Hi all,

I'm reviving this thread for the benefit of RxOSD integration.

On Thu, 15 Jan 2009, Jeffrey Hutzelman wrote:

> --On Thursday, January 15, 2009 02:00:09 PM -0500 Steven Jenkins 
> <steven.jenkins@gmail.com> wrote:
>
>> I would like to expose RPC code<->name mappings so that other programs
>> within OpenAFS can avoid hard-coding the mappings, as well as be able
>> to export them to the users (who might find them useful in debugging
>> network traces, for example, where their particular tool does not know
>> what a particular opcode corresponds to). From a user-level, it would
>> work as follows:
>> 
>> $ translate_rpc -name PR_INewEntry
>> 500

<snip>

>
> 1) Translation of opcodes to names could be done by an array lookup, but it 
> shouldn't be, because the required array will generally be quite large and 
> very sparse.  Instead, you should emit a _function_ which uses the same logic 
> as the ExecuteRequest function already emitted by rxgen, and which handles 
> large gaps in the opcode space in a reasonably efficient way.
>
> 2) Translation of names to opcode cannot be done by an array lookup, because 
> this is C, not awk or python, and strings cannot be used as array indices. 
> Again, I recommend actually emitting a function which does the required 
> translation.  This won't be like anything currently in OpenAFS, but shouldn't 
> be too hard to construct.  I recommend looking at using gperf to generate a 
> perfect hash table for each set of procedures.

I can see how a translate_rpc program could use a name -> RPC number
translation, but not the server binaries. The former should be a simple
script or program powered by a simple lookup table as suggested below.
Do we need proper functions that do that?

The only translation server or admin command binaries should need is
number -> name, as far as I can see it.

> It should be possible to get rxgen to produce these functions for any 
> interface, and preferably in a separate file from any of its other outputs, 
> so that they may be collected together into a library that has no other 
> dependencies.  I would also very much like to see a mode in which rxgen emits 
> a simple table of opcode numbers and procedure names, one per line. This 
> would be useful in constructing a standalone lookup tool that reads one table 
> per RPC interface (similar to something I've already done for com_err 
> tables), and may also be of use to the registrars in constructing some of the 
> procedure number tables we currently don't have.

Simple table can be generated using the attached patch. It's an awful lot 
of copy-paste and I'm not sure if it's valid. I'm also not yet sure
how to generate lookup functions. I have two approaches in mind:

1. make uses the lookup tables to feed gperf, and a custom script adds actual
    translation functions
2. rxgen receives another mode that generates functions which rely on gperf
    generated hash tables

Is that about what you had in mind?
Further suggestions/criticism?

Cheers
  - Felix
--579669762-1509803715-1241511170=:21930
Content-Type: TEXT/PLAIN; charset=US-ASCII; name=rpc-lookup-tables.patch
Content-Transfer-Encoding: BASE64
Content-Description: 
Content-Disposition: attachment; filename=rpc-lookup-tables.patch
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--579669762-1509803715-1241511170=:21930--