hw/xen: use G_GNUC_PRINTF/SCANF for various functions

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Acked-by: Anthony PERARD <anthony.perard@citrix.com>
Message-Id: <20221219130205.687815-3-berrange@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

hw/xen/xen-bus.c

@@ -561,6 +561,7 @@ void xen_device_backend_printf(XenDevice *xendev, const char *key,
     }
 }
 
+G_GNUC_SCANF(3, 4)
 static int xen_device_backend_scanf(XenDevice *xendev, const char *key,
                                     const char *fmt, ...)
 {

hw/xen/xen_pvdev.c

@@ -196,6 +196,7 @@ const char *xenbus_strstate(enum xenbus_state state)
  *  2 == noisy debug messages (logfile only).
  *  3 == will flood your log (logfile only).
  */
+G_GNUC_PRINTF(3, 0)
 static void xen_pv_output_msg(struct XenLegacyDevice *xendev,
                               FILE *f, const char *fmt, va_list args)
 {

include/hw/xen/xen-bus-helper.h

@@ -31,10 +31,12 @@ void xs_node_printf(struct xs_handle *xsh,  xs_transaction_t tid,
 /* Read from node/key unless node is empty, in which case read from key */
 int xs_node_vscanf(struct xs_handle *xsh,  xs_transaction_t tid,
                    const char *node, const char *key, Error **errp,
-                   const char *fmt, va_list ap);
+                   const char *fmt, va_list ap)
+    G_GNUC_SCANF(6, 0);
 int xs_node_scanf(struct xs_handle *xsh,  xs_transaction_t tid,
                   const char *node, const char *key, Error **errp,
-                  const char *fmt, ...);
+                  const char *fmt, ...)
+    G_GNUC_SCANF(6, 7);
 
 /* Watch node/key unless node is empty, in which case watch key */
 void xs_node_watch(struct xs_handle *xsh, const char *node, const char *key,

include/hw/xen/xen-bus.h

@@ -94,7 +94,8 @@ void xen_device_frontend_printf(XenDevice *xendev, const char *key,
     G_GNUC_PRINTF(3, 4);
 
 int xen_device_frontend_scanf(XenDevice *xendev, const char *key,
-                              const char *fmt, ...);
+                              const char *fmt, ...)
+    G_GNUC_SCANF(3, 4);
 
 void xen_device_set_max_grant_refs(XenDevice *xendev, unsigned int nr_refs,
                                    Error **errp);