[OpenBIOS] next-property

[Artyom Tarasenko]

On Thu, Jan 2, 2014 at 2:43 AM, Olivier Danet <odanet at caramail.com> wrote:
> 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.

Actually this matches pretty much with what OBP does:

ok showstack
ok " model" current-device next-property
fffe61e8 4 ffffffffffffffff ok drop type
name
ok " bozo" current-device next-property
ok

Artyom

>
> 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
> ===================================================================
>
> 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.
>
> Olivier
> (Btw, the OS is NetBSD :-)
>
>
> --
> OpenBIOS                 http://openbios.org/
> Mailinglist:  http://lists.openbios.org/mailman/listinfo
> Free your System - May the Forth be with you



-- 
Regards,
Artyom Tarasenko

linux/sparc and solaris/sparc under qemu blog:
http://tyom.blogspot.com/search/label/qemu