[PATCH libXi] Handle unknown device classes.

[Peter Hutterer]

If the server sends an unknown device class in response to an XIQueryDevice
call, no memory is allocated for these classes but we still write type
and sourceid as well as setting to->classes[i]. The latter causes multiple
classes to point to the same memory field.

Move the common code of assigning these three into the respective class type
handlers so to automatically skip any unknown classes.

Signed-off-by: Peter Hutterer <peter.hutterer at who-t.net>
---
 src/XExtInt.c       |   30 +++++++++++++++++++++---------
 src/XIQueryDevice.c |    2 +-
 2 files changed, 22 insertions(+), 10 deletions(-)

diff --git a/src/XExtInt.c b/src/XExtInt.c
index 86a780e..9e1ad19 100644
--- a/src/XExtInt.c
+++ b/src/XExtInt.c
@@ -98,7 +98,7 @@ extern int _XiGetDevicePresenceNotifyEvent(
     Display *		/* dpy */
 );
 
-int copy_classes(XIDeviceInfo *to, xXIAnyInfo* from, int nclasses);
+int copy_classes(XIDeviceInfo *to, xXIAnyInfo* from, int *nclasses);
 int size_classes(xXIAnyInfo* from, int nclasses);
 
 static XExtensionInfo *xinput_info;
@@ -1448,30 +1448,29 @@ size_classes(xXIAnyInfo* from, int nclasses)
  *             |______________________^
  */
 _X_HIDDEN int
-copy_classes(XIDeviceInfo* to, xXIAnyInfo* from, int nclasses)
+copy_classes(XIDeviceInfo* to, xXIAnyInfo* from, int *nclasses)
 {
     XIAnyClassInfo *any_lib;
     xXIAnyInfo *any_wire;
     void *ptr_lib;
     char *ptr_wire;
     int i, len;
+    int cls_idx = 0;
 
     if (!to->classes)
         return -1;
 
     ptr_wire = (char*)from;
     ptr_lib = to->classes;
-    to->classes = next_block(&ptr_lib, nclasses * sizeof(XIAnyClassInfo*));
+    to->classes = next_block(&ptr_lib, *nclasses * sizeof(XIAnyClassInfo*));
+    memset(to->classes, 0, sizeof(*nclasses * sizeof(XIAnyClassInfo*)));
     len = 0; /* count wire length */
 
-    for (i = 0; i < nclasses; i++)
+    for (i = 0; i < *nclasses; i++)
     {
         any_lib = (XIAnyClassInfo*)ptr_lib;
         any_wire = (xXIAnyInfo*)ptr_wire;
 
-        to->classes[i] = any_lib;
-        any_lib->type = any_wire->type;
-        any_lib->sourceid = any_wire->sourceid;
         switch(any_wire->type)
         {
             case XIButtonClass:
@@ -1485,6 +1484,8 @@ copy_classes(XIDeviceInfo* to, xXIAnyInfo* from, int nclasses)
                     cls_lib = next_block(&ptr_lib, sizeof(XIButtonClassInfo));
                     cls_wire = (xXIButtonInfo*)any_wire;
 
+                    cls_lib->type = cls_wire->type;
+                    cls_lib->sourceid = cls_wire->sourceid;
                     cls_lib->num_buttons = cls_wire->num_buttons;
                     size = ((((cls_wire->num_buttons + 7)/8) + 3)/4);
                     cls_lib->state.mask_len = size * 4;
@@ -1499,6 +1500,7 @@ copy_classes(XIDeviceInfo* to, xXIAnyInfo* from, int nclasses)
                     for (j = 0; j < cls_lib->num_buttons; j++)
                         cls_lib->labels[j] = *atoms++;
 
+                    to->classes[cls_idx++] = any_lib;
                     break;
                 }
             case XIKeyClass:
@@ -1509,12 +1511,15 @@ copy_classes(XIDeviceInfo* to, xXIAnyInfo* from, int nclasses)
                     cls_lib = next_block(&ptr_lib, sizeof(XIKeyClassInfo));
                     cls_wire = (xXIKeyInfo*)any_wire;
 
+                    cls_lib->type = cls_wire->type;
+                    cls_lib->sourceid = cls_wire->sourceid;
                     cls_lib->num_keycodes = cls_wire->num_keycodes;
                     cls_lib->keycodes = next_block(&ptr_lib,
                             cls_lib->num_keycodes * sizeof(int));
                     memcpy(cls_lib->keycodes, &cls_wire[1],
                             cls_lib->num_keycodes);
 
+                    to->classes[cls_idx++] = any_lib;
                     break;
                 }
             case XIValuatorClass:
@@ -1525,6 +1530,8 @@ copy_classes(XIDeviceInfo* to, xXIAnyInfo* from, int nclasses)
                     cls_lib = next_block(&ptr_lib, sizeof(XIValuatorClassInfo));
                     cls_wire = (xXIValuatorInfo*)any_wire;
 
+                    cls_lib->type = cls_wire->type;
+                    cls_lib->sourceid = cls_wire->sourceid;
                     cls_lib->number = cls_wire->number;
                     cls_lib->label  = cls_wire->label;
                     cls_lib->resolution = cls_wire->resolution;
@@ -1534,12 +1541,16 @@ copy_classes(XIDeviceInfo* to, xXIAnyInfo* from, int nclasses)
                     /* FIXME: fractional parts */
                     cls_lib->mode       = cls_wire->mode;
 
+                    to->classes[cls_idx++] = any_lib;
                 }
                 break;
         }
         len += any_wire->length * 4;
         ptr_wire += any_wire->length * 4;
     }
+
+    /* we may have skipped unknown classes, reset nclasses */
+    *nclasses = cls_idx;
     return len;
 }
 
@@ -1550,6 +1561,7 @@ wireToDeviceChangedEvent(xXIDeviceChangedEvent *in, XGenericEventCookie *cookie)
     XIDeviceChangedEvent *out;
     XIDeviceInfo info;
     int len;
+    int nclasses = in->num_classes;
 
     len = size_classes((xXIAnyInfo*)&in[1], in->num_classes);
 
@@ -1564,13 +1576,13 @@ wireToDeviceChangedEvent(xXIDeviceChangedEvent *in, XGenericEventCookie *cookie)
     out->deviceid = in->deviceid;
     out->sourceid = in->sourceid;
     out->reason = in->reason;
-    out->num_classes = in->num_classes;
 
     out->classes = (XIAnyClassInfo**)&out[1];
 
     info.classes = out->classes;
 
-    copy_classes(&info, (xXIAnyInfo*)&in[1], in->num_classes);
+    copy_classes(&info, (xXIAnyInfo*)&in[1], &nclasses);
+    out->num_classes = nclasses;
 
     return 1;
 }
diff --git a/src/XIQueryDevice.c b/src/XIQueryDevice.c
index 4e2f392..c8197d2 100644
--- a/src/XIQueryDevice.c
+++ b/src/XIQueryDevice.c
@@ -87,7 +87,7 @@ XIQueryDevice(Display *dpy, int deviceid, int *ndevices_return)
         ptr += ((wire->name_len + 3)/4) * 4;
 
         lib->classes = Xmalloc(size_classes((xXIAnyInfo*)ptr, lib->num_classes));
-        ptr += copy_classes(lib, (xXIAnyInfo*)ptr, lib->num_classes);
+        ptr += copy_classes(lib, (xXIAnyInfo*)ptr, &lib->num_classes);
     }
 
     Xfree(buf);
-- 
1.7.6

Cheers,
  Peter