Avoid memory leak on realloc failure in localRegisterFreeBoxCallback

Also avoids leaving invalid pointers in structures if realloc had to
move them elsewhere to make them larger.

Found by parfait 1.1 code analyzer:
   Memory leak of pointer 'newCallbacks' allocated with realloc(((char*)offman->FreeBoxesUpdateCallback), (8 * (offman->NumCallbacks + 1)))
        at line 328 of hw/xfree86/common/xf86fbman.c in function 'localRegisterFreeBoxCallback'.
          'newCallbacks' allocated at line 320 with realloc(((char*)offman->FreeBoxesUpdateCallback), (8 * (offman->NumCallbacks + 1))).
          newCallbacks leaks when newCallbacks != NULL at line 327.
   Memory leak of pointer 'newPrivates' allocated with realloc(((char*)offman->devPrivates), (8 * (offman->NumCallbacks + 1)))
        at line 328 of hw/xfree86/common/xf86fbman.c in function 'localRegisterFreeBoxCallback'.
          'newPrivates' allocated at line 324 with realloc(((char*)offman->devPrivates), (8 * (offman->NumCallbacks + 1))).
          newPrivates leaks when newCallbacks == NULL at line 327.

Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>

diff --git a/hw/xfree86/common/xf86fbman.c b/hw/xfree86/common/xf86fbman.c
index c2e7bab..4da6af2 100644 (file)
--- a/hw/xfree86/common/xf86fbman.c
+++ b/hw/xfree86/common/xf86fbman.c
@@ -320,15 +320,17 @@ localRegisterFreeBoxCallback(ScreenPtr pScreen,
     newCallbacks = realloc(offman->FreeBoxesUpdateCallback,
                            sizeof(FreeBoxCallbackProcPtr) *
                            (offman->NumCallbacks + 1));
+    if (!newCallbacks)
+        return FALSE;
+    else
+        offman->FreeBoxesUpdateCallback = newCallbacks;
 
     newPrivates = realloc(offman->devPrivates,
                           sizeof(DevUnion) * (offman->NumCallbacks + 1));
-
-    if (!newCallbacks || !newPrivates)
+    if (!newPrivates)
         return FALSE;
-
-    offman->FreeBoxesUpdateCallback = newCallbacks;
-    offman->devPrivates = newPrivates;
+    else
+        offman->devPrivates = newPrivates;
 
     offman->FreeBoxesUpdateCallback[offman->NumCallbacks] = FreeBoxCallback;
     offman->devPrivates[offman->NumCallbacks].ptr = devPriv;