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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>
This commit is contained in:
Joe Shaw 2010-10-14 15:09:20 -04:00 committed by Peter Hutterer
parent 424b856e8e
commit e354ccac36
2 changed files with 2 additions and 2 deletions
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2
dix/getevents.c
View File

@ -210,7 +210,7 @@ set_valuators(DeviceIntPtr dev, DeviceEvent* event, int first_valuator,
} }
memcpy(&event->valuators.data[first_valuator], memcpy(&event->valuators.data[first_valuator],
valuators, num_valuators * sizeof(uint32_t)); valuators, num_valuators * sizeof(int32_t));
} }

2
include/eventstr.h
View File

@ -99,7 +99,7 @@ struct _DeviceEvent
struct { struct {
uint8_t mask[(MAX_VALUATORS + 7)/8]; /**< Valuator mask */ uint8_t mask[(MAX_VALUATORS + 7)/8]; /**< Valuator mask */
uint8_t mode[(MAX_VALUATORS + 7)/8]; /**< Valuator mode (Abs or Rel)*/ 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 */ int32_t data_frac[MAX_VALUATORS]; /**< Fractional part for data */
} valuators; } valuators;
struct { struct {