Experimental Physics and
Industrial Control System

Dear Andrew,

I think you are wrong. Remember that the CALC expression must return TRUE or FALSE which will not be the case with A&2, A&4 ...
I guess my scheme is correct. Everything works except this problem with this spiral2mgr user that I don't understand (see the table below from my previous mail). We will try to overcome it in a way or another ... unless somebody has another idea about it !!!

J.F. Gournay
CEA Saclay
IRFU/SIS

-----Message d'origine-----
De : Andrew Johnson [mailto:[email protected]] 
Envoyé : mercredi 9 septembre 2009 16:56
À : [email protected]
Cc : GOURNAY Jean-Francois
Objet : Re: Access security problem

On Wednesday 09 September 2009 07:34:52 GOURNAY Jean-Francois wrote:
>
> I did more systematic tests and I have this strange situation:
>
> ASGVAL  UAG      spiral2  spiral2mgr      gournay
>
> 1       tous      W        W               W        OK
> 2       develop   -        - (should be W) -        WRONG
> 4       physique  W        -               -        OK
> 8       gournay   -        W (should be -) W        WRONG
>
> W : database WRITE access
> - :  no write access
>
> I modified the CALC expressions accordingly to Martin suggestion :
> CALC("A&1") instead of CALC("A&1=1").  But I don't think I have to write
> CALC (A>0&&A<2) as my A value comes from a longout record.

You're right there, but for historical reasons the relative precedence of 
the ">>" and "=" operators are different in C and CALC, so you do need to 
change your expressions:

>             CALC("A&1=1")
As Marty suggested "A&1" is sufficient here

>             CALC("A>>1=1")
CALC actually evaluates this as "A>>(1=1)" which is not what you mean.  You 
could use "(A>>1)=1" but I would suggest "A&2" here instead.

>             CALC("A>>2=1")
"A&4"

>             CALC("A>>3=1")
"A&8"

Using fewer operators will also parse and execute faster.

> This message sent yesterday didn't show up.

That's because you actually sent it to tech-talk-bounces@aps., not to 
tech-talk@aps., and I didn't get a chance to forward it manually before you 
re-sent it.

HTH,

- Andrew
-- 
The best FOSS code is written to be read by other humans -- Harold Welte

Replies:

Re: Access security problem Martin L. Smith

References:

TR: Access security problem GOURNAY Jean-Francois

RE: Access security problem GOURNAY Jean-Francois

Re: Access security problem Andrew Johnson

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