Re: PATCH: Add sys/personality (Re: Personality)

Re: PATCH: Add sys/personality (Re: Personality)

[H. J. Lu]

On Tue, Jul 16, 2002 at 09:16:48PM +0200, Carsten Langgaard wrote:
> Thanks.
> Now that we are at it, what should personality return in case it's called with a
> value, which isn't defined in the personality.h file.
> Should it return -EINVAL ?
> I don't think, that is the case at the moment, I believe you can set personality
> to anything.
> 

Like this?


H.J.
---
--- kernel/exec_domain.c.per	Mon Jun 10 10:05:27 2002
+++ kernel/exec_domain.c	Tue Jul 16 19:06:13 2002
@@ -223,7 +223,8 @@ sys_personality(u_long personality)
 
 	if (personality != 0xffffffff) {
 		set_personality(personality);
-		if (current->personality != personality)
+		if (personality < current->exec_domain->pers_low
+		    || personality > current->exec_domain->pers_high)
 			return -EINVAL;
 	}
 

Re: PATCH: Add sys/personality (Re: Personality)

[Carsten Langgaard]

"H. J. Lu" wrote:

> On Tue, Jul 16, 2002 at 09:16:48PM +0200, Carsten Langgaard wrote:
> > Thanks.
> > Now that we are at it, what should personality return in case it's called with a
> > value, which isn't defined in the personality.h file.
> > Should it return -EINVAL ?
> > I don't think, that is the case at the moment, I believe you can set personality
> > to anything.
> >
>
> Like this?
>

No, I don't think the patch is correct.
I don't know how this actually should work, maybe someone who do know can help out
here.
But it look like the idea is, that we have a default execution domain (linux), which
have pers_low = 0 (PER_LINUX) and pers_high = 0.
If one want other execution domains, one much call the register_exec_domain to
register the execution domain and personality.
So if personality is call with a value that isn't register, it then accept the
personality and sets the execution domain to the default settings (which is linux).
So the question is should personality, return -EINVAL, if it got a personality value
which hasn't been registered or should it accept the personality, but set the
execution domain to the default setting ?
If the later is true, should it also accept values outside the values defined in the
personality.h file ?

So what should the following user calls return, if not registered in the kernel?

personality(PER_BSD):
personality(0x47):

Could someone with a better understand than I, please comment this.

>
> H.J.
> ---
> --- kernel/exec_domain.c.per    Mon Jun 10 10:05:27 2002
> +++ kernel/exec_domain.c        Tue Jul 16 19:06:13 2002
> @@ -223,7 +223,8 @@ sys_personality(u_long personality)
>
>         if (personality != 0xffffffff) {
>                 set_personality(personality);
> -               if (current->personality != personality)
> +               if (personality < current->exec_domain->pers_low
> +                   || personality > current->exec_domain->pers_high)
>                         return -EINVAL;
>         }
>

--
_    _ ____  ___   Carsten Langgaard   Mailto:carstenl@mips.com
|\  /|||___)(___   MIPS Denmark        Direct: +45 4486 5527
| \/ |||    ____)  Lautrupvang 4B      Switch: +45 4486 5555
  TECHNOLOGIES     2750 Ballerup       Fax...: +45 4486 5556
                   Denmark             http://www.mips.com