migration: add status query functions

Add migration_is_active and migration_has_failed functions
to query migration state.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

migration.c

@@ -372,11 +372,22 @@ void remove_migration_state_change_notifier(Notifier *notify)
     notifier_list_remove(&migration_state_notifiers, notify);
 }
 
+bool migration_is_active(MigrationState *s)
+{
+    return s->state == MIG_STATE_ACTIVE;
+}
+
 bool migration_has_finished(MigrationState *s)
 {
     return s->state == MIG_STATE_COMPLETED;
 }
 
+bool migration_has_failed(MigrationState *s)
+{
+    return (s->state == MIG_STATE_CANCELLED ||
+            s->state == MIG_STATE_ERROR);
+}
+
 void migrate_fd_connect(MigrationState *s)
 {
     int ret;

migration.h

@@ -76,7 +76,9 @@ void migrate_fd_connect(MigrationState *s);
 
 void add_migration_state_change_notifier(Notifier *notify);
 void remove_migration_state_change_notifier(Notifier *notify);
+bool migration_is_active(MigrationState *);
 bool migration_has_finished(MigrationState *);
+bool migration_has_failed(MigrationState *);
 
 uint64_t ram_bytes_remaining(void);
 uint64_t ram_bytes_transferred(void);