nbd: produce a better error if neither host nor port is passed

Before:
    $ qemu-io-old
    qemu-io-old> open -r -o file.driver=nbd
    qemu-io-old: can't open device (null): Could not open image: Invalid argument
    $ ./qemu-io-old
    qemu-io-old> open -r -o file.driver=nbd,file.host=foo,file.path=bar
    path and host may not be used at the same time.
    qemu-io-old: can't open device (null): Could not open image: Invalid argument

After:
    $ ./qemu-io
    qemu-io> open -r -o file.driver=nbd
    one of path and host must be specified.
    qemu-io: can't open device (null): Could not open image: Invalid argument
    $ ./qemu-io
    qemu-io> open -r -o file.driver=nbd,file.host=foo,file.path=bar
    path and host may not be used at the same time.
    qemu-io: can't open device (null): Could not open image: Invalid argument

Next patch will fix the error propagation.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

1 files changed, 6 insertions, 7 deletions

diff --git a/block/nbd.c b/block/nbd.c
index abae506f04..a83e8565e5 100644
--- a/block/nbd.c
+++ b/block/nbd.c
@@ -192,19 +192,18 @@ static int nbd_config(BDRVNBDState *s, QDict *options, char **export)
 {
     Error *local_err = NULL;
 
-    if (qdict_haskey(options, "path")) {
-        if (qdict_haskey(options, "host")) {
+    if (qdict_haskey(options, "path") == qdict_haskey(options, "host")) {
+        if (qdict_haskey(options, "path")) {
             qerror_report(ERROR_CLASS_GENERIC_ERROR, "path and host may not "
                           "be used at the same time.");
-            return -EINVAL;
+        } else {
+            qerror_report(ERROR_CLASS_GENERIC_ERROR, "one of path and host "
+                          "must be specified.");
         }
-        s->client.is_unix = true;
-    } else if (qdict_haskey(options, "host")) {
-        s->client.is_unix = false;
-    } else {
         return -EINVAL;
     }
 
+    s->client.is_unix = qdict_haskey(options, "path");
     s->socket_opts = qemu_opts_create(&socket_optslist, NULL, 0,
                                       &error_abort);