Re: [OpenBIOS] next-property

[Artyom Tarasenko]

Hi Mark,

Happy New Year!

On Fri, Jan 3, 2014 at 1:42 PM, Mark Cave-Ayland
 wrote:
> On 02/01/14 01:43, Olivier Danet wrote:
>
> Hi Olivier,
>
> Happy New Year!
> > I may have found a bug in OpenBIOS.
> >
> > An OS uses the "nextprop" iterator to scan device properties, and
> > eventually
> > asks about nonexistant properties.
> > "const char *obp_nextprop(int node, const char *name)"
> > (arch/sparc32/romvec.c)
> > calls the "next-property" forth code, then pops the result.
> > According to the standard, next-property should return 0 if the property
> > selected
> > is the last _OR_ if the property does not exist.
> > The current code in forth/admin/devices.fs returns nothing when the
> > property does
> > not exit.
> >
> > For example (SPARC 32) :
> >
> > cd screen
> > " name" ?active-package next-property drop cr type
> > --> returns "device_type"
> >
> > " interrupts" ?active-package next-property
> > --> returns 0, this is the last property.
> >
> > " bozo" ?active-package next-property
> > --> returns nothing. Which, imho, is wrong.
> >
> > Here is a patch, I am not quite sure about it (debuting Forth)
> > but it helps the target OS :
> > Index: forth/device/property.fs
> >
> > --- forth/device/property.fs (révision 1246)
> > +++ forth/device/property.fs (copie de travail)
> > @@ -70,7 +70,7 @@
> > 2drop r> >dn.properties @
> > else
> > r> find-property dup if @ then
> > ?dup if >prop.next @ then
> > dup if >prop.next @ then
> >
> > then
> > ?dup if
>
> I've had a quick look at the patch and it looks good to me, although I'd
> probably like to test it on a few more OSs first before commit ;)
> > The standard asks for a pointer to a zero lenght string instead of zero,
> > the C code obp_nextprop() expects a zero. I don't know if it makes a
> > difference.
>
> Here the standard looks a bit confused with respect to next-property as it's
> clearly talking about NULL-terminated (C strings) as opposed to Forth
> strings ( addr len ) on the stack. Having said that, I'm fairly sure that
> string properties are stored NULL-terminated anyway although it's probably
> worth checking the contents of str in obp_nextprop() with gdb just to make
> sure.
> > Olivier
> > (Btw, the OS is NetBSD :-)
>
> Oh that's interesting. As part of my test suite, I regularly boot SPARC32
> NetBSD into graphics mode so I would expect this to already work.

Have you tried the following image?

ftp://ftp.netbsd.org/pub/NetBSD/NetBSD-6.1.2/sparc/installation/miniroot/miniroot.fs.gz

Artyom