+
+static uint64_t
+event_bitmask_of_event_list (value events)
+{
+ uint64_t r = 0;
+
+ while (events != Val_int (0)) {
+ r |= UINT64_C(1) << Int_val (Field (events, 0));
+ events = Field (events, 1);
+ }
+
+ return r;
+}
+
+/* Guestfs.set_event_callback */
+CAMLprim value
+ocaml_guestfs_set_event_callback (value gv, value closure, value events)
+{
+ CAMLparam3 (gv, closure, events);
+ char key[64];
+ int eh;
+ uint64_t event_bitmask;
+
+ guestfs_h *g = Guestfs_val (gv);
+
+ event_bitmask = event_bitmask_of_event_list (events);
+
+ value *root = guestfs_safe_malloc (g, sizeof *root);
+ *root = closure;
+
+ eh = guestfs_set_event_callback (g, event_callback_wrapper,
+ event_bitmask, 0, root);
+
+ if (eh == -1) {
+ free (root);
+ ocaml_guestfs_raise_error (g, "set_event_callback");
+ }
+
+ /* XXX This global root is generational, but we cannot rely on every
+ * user having the OCaml 3.11 version which supports this.
+ */
+ caml_register_global_root (root);
+
+ snprintf (key, sizeof key, "_ocaml_event_%d", eh);
+ guestfs_set_private (g, key, root);
+
+ CAMLreturn (Val_int (eh));
+}
+
+/* Guestfs.delete_event_callback */
+CAMLprim value
+ocaml_guestfs_delete_event_callback (value gv, value ehv)
+{
+ CAMLparam2 (gv, ehv);
+ char key[64];
+ int eh = Int_val (ehv);
+
+ guestfs_h *g = Guestfs_val (gv);
+
+ snprintf (key, sizeof key, "_ocaml_event_%d", eh);
+
+ value *root = guestfs_get_private (g, key);
+ if (root) {
+ caml_remove_global_root (root);
+ free (root);
+ guestfs_set_private (g, key, NULL);
+ guestfs_delete_event_callback (g, eh);
+ }
+
+ CAMLreturn (Val_unit);
+}
+
+static value **
+get_all_event_callbacks (guestfs_h *g, size_t *len_rtn)
+{
+ value **r;
+ size_t i;
+ const char *key;
+ value *root;
+
+ /* Count the length of the array that will be needed. */
+ *len_rtn = 0;
+ root = guestfs_first_private (g, &key);
+ while (root != NULL) {
+ if (strncmp (key, "_ocaml_event_", strlen ("_ocaml_event_")) == 0)
+ (*len_rtn)++;
+ root = guestfs_next_private (g, &key);
+ }
+
+ /* Copy them into the return array. */
+ r = guestfs_safe_malloc (g, sizeof (value *) * (*len_rtn));
+
+ i = 0;
+ root = guestfs_first_private (g, &key);
+ while (root != NULL) {
+ if (strncmp (key, "_ocaml_event_", strlen ("_ocaml_event_")) == 0) {
+ r[i] = root;
+ i++;
+ }
+ root = guestfs_next_private (g, &key);
+ }
+
+ return r;
+}
+
+/* Could do better: http://graphics.stanford.edu/~seander/bithacks.html */
+static int
+event_bitmask_to_event (uint64_t event)
+{
+ int r = 0;
+
+ while (event >>= 1)
+ r++;
+
+ return r;
+}
+
+static void
+event_callback_wrapper (guestfs_h *g,
+ void *data,
+ uint64_t event,
+ int event_handle,
+ int flags,
+ const char *buf, size_t buf_len,
+ const uint64_t *array, size_t array_len)
+{
+ CAMLparam0 ();
+ CAMLlocal5 (gv, evv, ehv, bufv, arrayv);
+ CAMLlocal2 (rv, v);
+ value *root;
+ size_t i;
+
+ root = guestfs_get_private (g, "_ocaml_g");
+ gv = *root;
+
+ /* Only one bit should be set in 'event'. Which one? */
+ evv = Val_int (event_bitmask_to_event (event));
+
+ ehv = Val_int (event_handle);
+
+ bufv = caml_alloc_string (buf_len);
+ memcpy (String_val (bufv), buf, buf_len);
+
+ arrayv = caml_alloc (array_len, 0);
+ for (i = 0; i < array_len; ++i) {
+ v = caml_copy_int64 (array[i]);
+ Store_field (arrayv, i, v);
+ }
+
+ value args[5] = { gv, evv, ehv, bufv, arrayv };
+
+ caml_leave_blocking_section ();
+ rv = caml_callbackN_exn (*(value*)data, 5, args);
+ caml_enter_blocking_section ();
+
+ /* Callbacks shouldn't throw exceptions. There's not much we can do
+ * except to print it.
+ */
+ if (Is_exception_result (rv))
+ fprintf (stderr,
+ "libguestfs: uncaught OCaml exception in event callback: %s",
+ caml_format_exception (Extract_exception (rv)));
+
+ CAMLreturn0;
+}