[Qemu-devel] [PATCH 3/5] net: raise an error if -net type is invalid

[Stefan Hajnoczi <stefanha@redhat.com>]

When a -net type is used that was not compiled into the binary there
should be an error message.

Note the special case for -net none, which is a no-op.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 net/net.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/net/net.c b/net/net.c
index 3352b2b..85a9ddb 100644
--- a/net/net.c
+++ b/net/net.c
@@ -922,6 +922,17 @@ static int net_client_init1(const void *object, int is_netdev, Error **errp)
         }
         /* missing optional values have been initialized to "all bits zero" */
         name = u.net->has_id ? u.net->id : u.net->name;
+
+        if (opts->kind == NET_CLIENT_OPTIONS_KIND_NONE) {
+            return 0; /* nothing to do */
+        }
+
+        if (!net_client_init_fun[opts->kind]) {
+            error_set(errp, QERR_INVALID_PARAMETER_VALUE, "type",
+                      "a net backend type (maybe it is not compiled "
+                      "into this binary)");
+            return -1;
+        }
     }
 
     if (net_client_init_fun[opts->kind]) {
-- 
2.4.1