blkdebug: Allow usage without config file

As soon as new rules can be set during runtime, as introduced by the
next patch, blkdebug makes sense even without a config file.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/block/blkdebug.c b/block/blkdebug.c
index d61ece86a..c9041ec3d 100644
--- a/block/blkdebug.c
+++ b/block/blkdebug.c
@@ -240,6 +240,11 @@ static int read_config(BDRVBlkdebugState *s, const char *filename)
     int ret;
     struct add_rule_data d;
 
+    /* Allow usage without config file */
+    if (!*filename) {
+        return 0;
+    }
+
     f = fopen(filename, "r");
     if (f == NULL) {
         return -errno;