X-Git-Url: http://git.annexia.org/?a=blobdiff_plain;f=generator%2Fgenerator_ruby.ml;h=d0551573a1f11f116ddda47eadb5ecfacf7dd4b1;hb=25791edff58665a949807081d131ef74e74a2d7c;hp=84d10e0017668a3286551794649743ffc3d9741a;hpb=cf26ef818e918c8c32658399e8aa9e31289109a7;p=libguestfs.git

diff --git a/generator/generator_ruby.ml b/generator/generator_ruby.ml
index 84d10e0..d055157 100644
--- a/generator/generator_ruby.ml
+++ b/generator/generator_ruby.ml
@@ -55,6 +55,8 @@ static VALUE c_guestfs;			/* guestfs_h handle */
 static VALUE e_Error;			/* used for all errors */
 
 static void ruby_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);
+static VALUE ruby_event_callback_wrapper_wrapper (VALUE argv);
+static VALUE ruby_event_callback_handle_exception (VALUE not_used, VALUE exn);
 static VALUE **get_all_event_callbacks (guestfs_h *g, size_t *len_rtn);
 
 static void
@@ -213,6 +215,7 @@ ruby_event_callback_wrapper (guestfs_h *g,
 {
   size_t i;
   VALUE eventv, event_handlev, bufv, arrayv;
+  VALUE argv[5];
 
   eventv = ULL2NUM (event);
   event_handlev = INT2NUM (event_handle);
@@ -223,12 +226,55 @@ ruby_event_callback_wrapper (guestfs_h *g,
   for (i = 0; i < array_len; ++i)
     rb_ary_push (arrayv, ULL2NUM (array[i]));
 
-  /* XXX If the Ruby callback raises any sort of exception then
-   * it causes the process to segfault.  I don't understand how
-   * to catch exceptions here.
+  /* This is a crap limitation of rb_rescue.
+   * http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/~poffice/mail/ruby-talk/65698
    */
-  rb_funcall (*(VALUE *) data, rb_intern (\"call\"), 4,
-              eventv, event_handlev, bufv, arrayv);
+  argv[0] = * (VALUE *) data; /* function */
+  argv[1] = eventv;
+  argv[2] = event_handlev;
+  argv[3] = bufv;
+  argv[4] = arrayv;
+
+  rb_rescue (ruby_event_callback_wrapper_wrapper, (VALUE) argv,
+             ruby_event_callback_handle_exception, Qnil);
+}
+
+static VALUE
+ruby_event_callback_wrapper_wrapper (VALUE argvv)
+{
+  VALUE *argv = (VALUE *) argvv;
+  VALUE fn, eventv, event_handlev, bufv, arrayv;
+
+  fn = argv[0];
+
+  /* Check the Ruby callback still exists.  For reasons which are not
+   * fully understood, even though we registered this as a global root,
+   * it is still possible for the callback to go away (fn value remains
+   * but its type changes from T_DATA to T_NONE).  (RHBZ#733297)
+   */
+  if (rb_type (fn) != T_NONE) {
+    eventv = argv[1];
+    event_handlev = argv[2];
+    bufv = argv[3];
+    arrayv = argv[4];
+
+    rb_funcall (fn, rb_intern (\"call\"), 4,
+                eventv, event_handlev, bufv, arrayv);
+  }
+
+  return Qnil;
+}
+
+static VALUE
+ruby_event_callback_handle_exception (VALUE not_used, VALUE exn)
+{
+  /* Callbacks aren't supposed to throw exceptions.  The best we
+   * can do is to print the error.
+   */
+  fprintf (stderr, \"libguestfs: exception in callback: %%s\\n\",
+           StringValueCStr (exn));
+
+  return Qnil;
 }
 
 static VALUE **