[oe] xmonobut

[Alain2210]

Hello,

thanks for the answers.

Selon Phil Blundell <pb at reciva.com>:

> On Tue, 2009-11-03 at 14:51 +0100, Holger Hans Peter Freyther wrote:
> > On Monday 28 September 2009 02:16:07 Alain2210 wrote:
> > > Hello,
> > >
> > > xmonobut segfault. I need this patch to get it works again.
> >
> > > -  unsigned char map[6];
> > > +  unsigned char map[31];
> > ...
> > > +      buts = XGetPointerMapping(dpy, map, 32);
> > ,,.
> > > +      while((rst = XSetPointerMapping(dpy, map, 32)) == MappingBusy);
> >
> > 31. vs 32... please send an updated patch

Sorry for the mistake.

> Looking at this patch again, I think it is just broken and (even aside
> from the 31/32 thing) should not be applied.

I have seen in the september answer that you says that xlib should be corrected.
In fact, I do not understand the behaviour of XG/SetPointerMapping since the
third argument seems to be ignored in a certain sense.

>
> I guess the cause of the original segfault was that "buts" is set to a
> value greater than six and hence the XSetPointerMapping() call runs off
> the end of the array. However, the solution presented in the patch,
> i.e. just ignoring the return value from XGetPointerMapping()
> altogether, doesn't seem too good either since this will cause
> XSetPointerMapping() to read uninitialised garbage from the balance of
> the array.
>
> A minimal fix for the original crash would probably be to insert
> something like:
>
> if (buts > sizeof(map))
>   buts = sizeof(map);
>
> after the XGetPointerMapping() call.

I will try this. (and will try to remember what was exactly the problem).

> A slightly better fix would
> perhaps be to make an initial call to XGetPointerMapping() with nmap=0
> to find out how many buttons are present, then to dynamically allocate
> an array of the right size and read the mapping into it.

Sorry, it is beyond my capabilities.


Thanks,

Alain