fix a sign problem with valuator data.

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 <joeshaw@litl.com>
Reviewed-by: Chase Douglas <chase.douglas@canonical.com>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

1 files changed, 1 insertions, 1 deletions

diff --git a/dix/getevents.c b/dix/getevents.c
index ecbf416b1..3731a4a38 100644
--- a/dix/getevents.c
+++ b/dix/getevents.c
@@ -210,7 +210,7 @@ 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));
 
 }