Re: [PATCH] Smackv10: Smack rules grammar + their stateful parser

From: Ahmed S. Darwish
Date: Mon Nov 05 2007 - 18:38:36 EST


On 11/5/07, Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
>
>
> On Mon, 5 Nov 2007, Ahmed S. Darwish wrote:
>
> > On Sun, Nov 04, 2007 at 12:28:48PM +0000, Pavel Machek wrote:
> > >
> > > Can we avoid string parsers in the kernel?
> > >
> >
> > Ok, Could someone suggest a better idea please ?.
>
> I personally think string parsers are *much* better than the alternatives
> (which basically boil down to nasty binary interfaces)
>
> > I thought about packing the rules in a structure and sending
> > it over an ioctl() command. Is this applicable ?
>
> That's *MUCH* worse.
>
> Strings are nice. They aren't that complex, and as long as it's not a
> performance-critical area, there are basically no downsides.
>
> Binary structures and ioctl's are *much* worse. They are totally
> undebuggable with generic tools (think "echo" or "strace"), and they are a
> total nightmare to parse across architectures and pointer sizes.
>
> So the rule should be: always use strings if at all possible and relevant.
> If the data is fundamentally binary, it shouldn't be re-coded to ascii (no
> real advantage), but if the data is "stringish", and there aren't big
> performance issues, then keep it as strings.
>

Thanks a lot for such a kind advice. I'll keep that in my mind.

Regards,

--
Ahmed S. Darwish
Homepage: http://darwish.07.googlepages.com
Blog: http://darwish-07.blogspot.com
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