Re: [ros-dev] very confused

[Alex Ionescu]

Timo Kreuzer wrote:

>   rené Tournois @mailhost.geldorp.nl schrieb:
>
> >   At 15:11 17/02/2006 -0000, you wrote:
> >
> >  I apologize for this second intrusion, but i have some difficulties
> >  to really understand this:
> >
> >   
> >
> > >   Define 'MS code'. If we're talking
> > > about leaked source code, then 
> > >  that is
> > >  true.
> > >       
> >
> >  But you said elsewhere that there was _no_ leaked source, so that
> >  the only problem should be with your next words:
> >     
>  It's a comments on "...that there is still no Microsoft-Code found in 
>  ROS."
>  It is true that there is *no* leaked source code inside reactos.
>
> > >   If
> > > we're talking about small chunks of assembly from dissasembled MS
> > >  binaries, then that is what the audit hopes to uncover and remove. 
> > >  Once the
> > >  audit is complete, we can also say we know this to be true, at the 
> > >  moment we
> > >  don't know.
> > >       
> >
> >  ... and this one sounds strange to me, because i saw several messages
> >  talking in terms of *year* (?!), for the audit.
> >
> >  Well, i just downloaded the ReactOS Sources, and searched for all the
> >  Files having an "__asm__" Statements inside, after having saved in a 
> >  [...]
> >     
>  I think this only applies to the bootsector, wich has asm directly 
>  taken from disassemblies in it.
>
> >   I stopped there, because i said to me that it was
> > stupid to read that
> >  way, and that i was possibly missing the Files of real interrest for
> >  the Audit. But all i have seen does not explain to me, how it could
> >  ever take one year for proof-reading so few, and so small, "__asm__"
> >  statements.
> >
> >  What am i missing?
> >     
>  I think what Ged was talking about was disassemblies converted into C. 
>  And this can be found by looking for typical things of that kind of code:
>  - Magical number inside C code. Normally constants are used or the 
>  numbers are commented or really obvios. But when you don't know why 
>  there's a constant 0x2342 then you don't really know how to call it. 
>  In disc.c there's a constant called PARTITION_MAGIC ;-) 
WINE code is supposedly "clean as crystal" yet their low-level native 
modules/kernel libraries are full of magic numbers. All my kernel code 
is reversed and doesn't have a single magic constant.

>   - excessive gotos: You would normally not use any
> gotos, but it can be 
>  hard to identify complex structures of for, if, while,... inside asm 
>  code, so you do it like it's done in asm: with gotos. It doesn't look 
>  good, but it works. 
A good reverser such as myself can identify the complex structures. A 
bad coder can implement clean code with lots of gotos.

In the end, one of the best ways to figure out if something is reversed 
is not the code style, but the code quality. You tell yourself "Ok..so 
here we have a low-level kernel function that no driver out there uses, 
and which has absolutely no test case, but has 500 lines of perfectly 
implemented code which seem to magically know how to handle every 
combination of parameters, flags and situations. How was this coded?"

Best regards,
Alex Ionescu

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