Handle unknown device classes.

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@who-t.net>
(cherry picked from commit 91f928a70246c26cbee00bf59a8e318e9317142e)

2 files changed, 23 insertions, 11 deletions

diff --git a/src/XExtInt.c b/src/XExtInt.c
index 134ccc6..2ce2d44 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;
@@ -1449,30 +1449,29 @@ 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:
@@ -1486,6 +1485,8 @@ 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;
@@ -1500,6 +1501,7 @@ 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:
@@ -1510,12 +1512,15 @@ 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:
@@ -1526,6 +1531,8 @@ 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;
@@ -1535,12 +1542,16 @@ 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;
 }
 
@@ -1551,6 +1562,7 @@ 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);
 
@@ -1565,13 +1577,13 @@ 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..c22aee1 100644
--- a/src/XIQueryDevice.c
+++ b/src/XIQueryDevice.c
@@ -29,7 +29,7 @@
 #include <X11/extensions/extutil.h>
 #include "XIint.h"
 
-extern int copy_classes(XIDeviceInfo* to, xXIAnyInfo* from, int nclasses);
+extern int copy_classes(XIDeviceInfo* to, xXIAnyInfo* from, int *nclasses);
 extern int size_classes(xXIAnyInfo* from, int nclasses);
 
 XIDeviceInfo*
@@ -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);