xend, acm: Extend Xen-API with function to reset the policy

This patch extends the Xen-API and the legacy XML-RPC interface with a
function to reset the policy on the system (through an update with the
default policy). I adapted the code in 'xm resetpolicy' to use this
now.

This patch also extends libxen and the documentation to reflect the
new function.

Signed-off-by: Stefan Berger <stefanb@us.ibm.com>

2 files changed, 31 insertions, 0 deletions

diff --git a/tools/libxen/include/xen/api/xen_xspolicy.h b/tools/libxen/include/xen/api/xen_xspolicy.h
index 3ecdc4b54d..b0808f4d57 100644
--- a/tools/libxen/include/xen/api/xen_xspolicy.h
+++ b/tools/libxen/include/xen/api/xen_xspolicy.h
@@ -240,6 +240,19 @@ xen_xspolicy_set_xspolicy(xen_session *session, xen_xs_policystate **result,
                           bool overwrite);
 
 
+
+/**
+ * Attempt to reset the system's policy to the DEFAULT policy for the
+ * respective policy type. This is done by updating the system and therefore
+ * underlies the same restrictions of a policy update. This operation may
+ * for example fail if other domains than Domain-0 are running and have
+ * different labels than Domain-0.
+ */
+bool
+xen_xspolicy_reset_xspolicy(xen_session *session, xen_xs_policystate **result,
+                            xs_type type);
+
+
 /**
  * Remove any policy from having the system booted with.
  */
diff --git a/tools/libxen/src/xen_xspolicy.c b/tools/libxen/src/xen_xspolicy.c
index ccafe1f4e8..e5f290c1a1 100644
--- a/tools/libxen/src/xen_xspolicy.c
+++ b/tools/libxen/src/xen_xspolicy.c
@@ -225,6 +225,24 @@ xen_xspolicy_set_xspolicy(xen_session *session, xen_xs_policystate **result,
 
 
 bool
+xen_xspolicy_reset_xspolicy(xen_session *session, xen_xs_policystate **result,
+                            xs_type type)
+{
+    abstract_value param_values[] =
+        {
+            { .type = &abstract_type_int,
+              .u.int_val = type },
+        };
+
+    abstract_type result_type = xen_xs_policystate_abstract_type_;
+
+    *result = NULL;
+    XEN_CALL_("XSPolicy.reset_xspolicy");
+    return session->ok;
+}
+
+
+bool
 xen_xspolicy_get_xspolicy(xen_session *session, xen_xs_policystate **result)
 {
     abstract_value param_values[] =