duid: test that we actually have a uuid on Linux

diff --git a/src/duid.c b/src/duid.c
index cc53f9bdc53b24cdb321aff83212d833546ac416..4faab9aba16456a943803ba799973d5bb0a7433f 100644 (file)
--- a/src/duid.c
+++ b/src/duid.c
@@ -88,7 +88,7 @@ duid_machineuuid(char *uuid, size_t uuid_len)
        }
        len = strlen(uuid) + 1;
        fclose(fp);
-       r = 0;
+       r = len == 1 ? -1 : 0;
 #else
        r = -1;
        errno = ENOSYS;