[Libguestfs] Segmentation fault when trying to add binding

[Shahar Havivi]

Hi,

I am trying to add xmlXPathRegisterNs() to v2v/xml-c.c but I get a seg fault,
the signature should be:
http://xmlsoft.org/html/libxml-xpathInternals.html#xmlXPathRegisterNs

I think I am wrong in CAMLparam and CAMLlocal...,
Following is the patch:

===================================================================================
diff --git a/v2v/xml-c.c b/v2v/xml-c.c
index 4c9bc77..a917c24 100644
--- a/v2v/xml-c.c
+++ b/v2v/xml-c.c
@@ -141,6 +141,16 @@ v2v_xml_xpath_new_context (value docv)
 }
 
 value
+v2v_xml_xpath_register_ns (value prefix, value uri, value xpathctx)
+{
+  CAMLparam3 (prefix, uri, xpathctx);
+  CAMLlocal1 (retval);
+  retval = xmlXPathRegisterNs (BAD_CAST String_val (prefix), BAD_CAST String_val (uri), xpathctx);
+
+  CAMLreturn (retval);
+}
+
+value
 v2v_xml_xpath_eval_expression (value xpathctxv, value exprv)
 {
   CAMLparam2 (xpathctxv, exprv);
diff --git a/v2v/xml.ml b/v2v/xml.ml
index 78cb022..2e4d222 100644
--- a/v2v/xml.ml
+++ b/v2v/xml.ml
@@ -31,6 +31,7 @@ type node = doc * node_ptr
 external parse_memory : string -> doc = "v2v_xml_parse_memory"
 external xpath_new_context : doc -> xpathctx = "v2v_xml_xpath_new_context"
 external xpath_eval_expression : xpathctx -> string -> xpathobj = "v2v_xml_xpath_eval_expression"
+external xpath_register_ns : string -> string -> xpathctx -> int = "v2v_xml_xpath_register_ns"
 
 external xpathobj_nr_nodes : xpathobj -> int = "v2v_xml_xpathobj_nr_nodes"
 external xpathobj_get_node_ptr : xpathobj -> int -> node_ptr = "v2v_xml_xpathobj_get_node_ptr"
diff --git a/v2v/xml.mli b/v2v/xml.mli
index 38bb9cd..cab4395 100644
--- a/v2v/xml.mli
+++ b/v2v/xml.mli
@@ -29,6 +29,8 @@ val xpath_new_context : doc -> xpathctx
 (** xmlXPathNewContext *)
 val xpath_eval_expression : xpathctx -> string -> xpathobj
 (** xmlXPathEvalExpression *)
+val xpath_register_ns : string -> string -> xpathctx -> int
+(** xmlXPathRegisterNs *)
 
 val xpathobj_nr_nodes : xpathobj -> int
 (** Get the number of nodes in the node set of the xmlXPathObjectPtr. *)
===================================================================================