On Thu, 2010-10-14 at 15:09 -0400, Joe Shaw wrote: > From: Joe Shaw <[email protected]> > > Without this patch, any negative valuator value is wrong when returned > from XQueryDeviceState(). This is a regression from at least xserver > 1.4. > > Valuator data is set in dix/getevents.c:set_valuators() by copying > signed int values into an unsigned int field > DeviceEvent.valuators.data. > > That data is converted into a double with an implicit cast by > assignment to axisVal[i] in Xi/exevents.c:UpdateDeviceState(). > > That double is converted back to a signed int in > queryst.c:ProcXQueryDeviceState(). If the original value in > set_valuators() is negative, the double value will be > 2^31 and the > conversion back to a signed int is undefined. (Although I > consistently see the value -2^31.) > > Fix this by changing the definition of DeviceEvent.valuators.data from > uint32_t to int32_t. > > Signed-off-by: Joe Shaw <[email protected]> > --- > dix/getevents.c | 2 +- > include/eventstr.h | 2 +- > 2 files changed, 2 insertions(+), 2 deletions(-) > > diff --git a/dix/getevents.c b/dix/getevents.c > index 82bb77b..531595e 100644 > --- a/dix/getevents.c > +++ b/dix/getevents.c > @@ -177,7 +177,7 @@ set_valuators(DeviceIntPtr dev, DeviceEvent* event, int > first_valuator, > } > > memcpy(&event->valuators.data[first_valuator], > - valuators, num_valuators * sizeof(uint32_t)); > + valuators, num_valuators * sizeof(int32_t)); > > } > > diff --git a/include/eventstr.h b/include/eventstr.h > index 433227e..377cceb 100644 > --- a/include/eventstr.h > +++ b/include/eventstr.h > @@ -99,7 +99,7 @@ struct _DeviceEvent > struct { > uint8_t mask[(MAX_VALUATORS + 7)/8]; /**< Valuator mask */ > uint8_t mode[(MAX_VALUATORS + 7)/8]; /**< Valuator mode (Abs or > Rel)*/ > - uint32_t data[MAX_VALUATORS]; /**< Valuator data */ > + int32_t data[MAX_VALUATORS]; /**< Valuator data */ > int32_t data_frac[MAX_VALUATORS]; /**< Fractional part for data > */ > } valuators; > struct {
I can't think of any reason this fix would cause issues except for values > 2^31. I don't think that ever happens :). Reviewed-by: Chase Douglas <[email protected]> _______________________________________________ [email protected]: X.Org development Archives: http://lists.x.org/archives/xorg-devel Info: http://lists.x.org/mailman/listinfo/xorg-devel
