xen: allow getting < max typed parameters

Allow the user to call with nparams too small, per API documentation.

* src/xen/xen_hypervisor.c (xenHypervisorGetSchedulerParameters):
Allow fewer than max.
* src/xen/xend_internal.c (xenDaemonGetSchedulerParameters):
Likewise.

src/xen/xen_hypervisor.c

@@ -1274,11 +1274,6 @@ xenHypervisorGetSchedulerParameters(virDomainPtr domain,
                 TODO
                 return(-1);
             case XEN_SCHEDULER_CREDIT:
-                if (*nparams < XEN_SCHED_CRED_NPARAM) {
-                    virXenError(VIR_ERR_INVALID_ARG,
-                                "%s", _("Invalid parameter count"));
-                    return -1;
-                }
                 memset(&op_dom, 0, sizeof(op_dom));
                 op_dom.cmd = XEN_V2_OP_SCHEDULER;
                 op_dom.domain = (domid_t) domain->id;
@@ -1298,17 +1293,20 @@ xenHypervisorGetSchedulerParameters(virDomainPtr domain,
                 params[0].type = VIR_TYPED_PARAM_UINT;
                 params[0].value.ui = op_dom.u.getschedinfo.u.credit.weight;
 
-                if (virStrcpyStatic(params[1].field,
-                                    VIR_DOMAIN_SCHEDULER_CAP) == NULL) {
-                    virXenError(VIR_ERR_INTERNAL_ERROR,
-                                "Cap %s too big for destination",
-                                VIR_DOMAIN_SCHEDULER_CAP);
-                    return -1;
+                if (*nparams > 1) {
+                    if (virStrcpyStatic(params[1].field,
+                                        VIR_DOMAIN_SCHEDULER_CAP) == NULL) {
+                        virXenError(VIR_ERR_INTERNAL_ERROR,
+                                    "Cap %s too big for destination",
+                                    VIR_DOMAIN_SCHEDULER_CAP);
+                        return -1;
+                    }
+                    params[1].type = VIR_TYPED_PARAM_UINT;
+                    params[1].value.ui = op_dom.u.getschedinfo.u.credit.cap;
                 }
-                params[1].type = VIR_TYPED_PARAM_UINT;
-                params[1].value.ui = op_dom.u.getschedinfo.u.credit.cap;
 
-                *nparams = XEN_SCHED_CRED_NPARAM;
+                if (*nparams > XEN_SCHED_CRED_NPARAM)
+                    *nparams = XEN_SCHED_CRED_NPARAM;
                 break;
             default:
                 virXenErrorFunc(VIR_ERR_INVALID_ARG, __FUNCTION__,

src/xen/xend_internal.c

@@ -3614,12 +3614,6 @@ xenDaemonGetSchedulerParameters(virDomainPtr domain,
             TODO
             goto error;
         case XEN_SCHED_CRED_NPARAM:
-            if (*nparams < XEN_SCHED_CRED_NPARAM) {
-                virXendError(VIR_ERR_INVALID_ARG,
-                             "%s", _("Invalid parameter count"));
-                goto error;
-            }
-
             /* get cpu_weight/cpu_cap from xend/domain */
             if (sexpr_node(root, "domain/cpu_weight") == NULL) {
                 virXendError(VIR_ERR_INTERNAL_ERROR,
@@ -3642,16 +3636,20 @@ xenDaemonGetSchedulerParameters(virDomainPtr domain,
             params[0].type = VIR_TYPED_PARAM_UINT;
             params[0].value.ui = sexpr_int(root, "domain/cpu_weight");
 
-            if (virStrcpyStatic(params[1].field,
-                                VIR_DOMAIN_SCHEDULER_CAP) == NULL) {
-                virXendError(VIR_ERR_INTERNAL_ERROR,
-                             _("Cap %s too big for destination"),
-                             VIR_DOMAIN_SCHEDULER_CAP);
-                goto error;
+            if (*nparams > 1) {
+                if (virStrcpyStatic(params[1].field,
+                                    VIR_DOMAIN_SCHEDULER_CAP) == NULL) {
+                    virXendError(VIR_ERR_INTERNAL_ERROR,
+                                 _("Cap %s too big for destination"),
+                                 VIR_DOMAIN_SCHEDULER_CAP);
+                    goto error;
+                }
+                params[1].type = VIR_TYPED_PARAM_UINT;
+                params[1].value.ui = sexpr_int(root, "domain/cpu_cap");
             }
-            params[1].type = VIR_TYPED_PARAM_UINT;
-            params[1].value.ui = sexpr_int(root, "domain/cpu_cap");
-            *nparams = XEN_SCHED_CRED_NPARAM;
+
+            if (*nparams > XEN_SCHED_CRED_NPARAM)
+                *nparams = XEN_SCHED_CRED_NPARAM;
             ret = 0;
             break;
         default: