[Qemu-devel] [PATCH v2 10/15] nbd: allow setting of an export name for qemu-nbd server

["Daniel P. Berrange" <berrange@redhat.com>]

The qemu-nbd server currently always uses the old style protocol
since it never sets any export name. This is a problem because
future TLS support will require use of the new style protocol
negotiation.

This adds a "--exportname NAME" argument to qemu-nbd which allows
the user to set an explicit export name. When --exportname is
set the server will always use the new style protocol.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
---
 qemu-nbd.c    | 14 ++++++++++++--
 qemu-nbd.texi |  3 +++
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/qemu-nbd.c b/qemu-nbd.c
index 2c47fc6..7933ff5 100644
--- a/qemu-nbd.c
+++ b/qemu-nbd.c
@@ -47,6 +47,7 @@
 #define QEMU_NBD_OPT_OBJECT        5
 
 static NBDExport *exp;
+static bool newproto;
 static int verbose;
 static char *srcpath;
 static SocketAddress *saddr;
@@ -341,7 +342,7 @@ static gboolean nbd_accept(QIOChannel *ioc, GIOCondition cond, gpointer opaque)
         return TRUE;
     }
 
-    if (nbd_client_new(exp, cioc, nbd_client_closed)) {
+    if (nbd_client_new(newproto ? NULL : exp, cioc, nbd_client_closed)) {
         nb_fds++;
         nbd_update_server_watch();
     }
@@ -437,7 +438,7 @@ int main(int argc, char **argv)
     off_t fd_size;
     QemuOpts *sn_opts = NULL;
     const char *sn_id_or_name = NULL;
-    const char *sopt = "hVb:o:p:rsnP:c:dvk:e:f:tl:";
+    const char *sopt = "hVb:o:p:rsnP:c:dvk:e:f:tl:x:";
     struct option lopt[] = {
         { "help", 0, NULL, 'h' },
         { "version", 0, NULL, 'V' },
@@ -461,6 +462,7 @@ int main(int argc, char **argv)
         { "persistent", 0, NULL, 't' },
         { "verbose", 0, NULL, 'v' },
         { "object", 1, NULL, QEMU_NBD_OPT_OBJECT },
+        { "exportname", 1, NULL, 'x' },
         { NULL, 0, NULL, 0 }
     };
     int ch;
@@ -478,6 +480,7 @@ int main(int argc, char **argv)
     BlockdevDetectZeroesOptions detect_zeroes = BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF;
     QDict *options = NULL;
     QemuOpts *opts;
+    const char *exportname = NULL;
 
     /* The client thread uses SIGTERM to interrupt the server.  A signal
      * handler ensures that "qemu-nbd -v -c" exits with a nice status code.
@@ -613,6 +616,9 @@ int main(int argc, char **argv)
         case 't':
             persistent = 1;
             break;
+        case 'x':
+            exportname = optarg;
+            break;
         case 'v':
             verbose = 1;
             break;
@@ -780,6 +786,10 @@ int main(int argc, char **argv)
     if (!exp) {
         errx(EXIT_FAILURE, "%s", error_get_pretty(local_err));
     }
+    if (exportname) {
+        nbd_export_set_name(exp, exportname);
+        newproto = true;
+    }
 
     server_ioc = qio_channel_socket_new();
     if (qio_channel_socket_listen_sync(server_ioc, saddr, &local_err) < 0) {
diff --git a/qemu-nbd.texi b/qemu-nbd.texi
index 9f9daca..22d6b5a 100644
--- a/qemu-nbd.texi
+++ b/qemu-nbd.texi
@@ -63,6 +63,9 @@ Export QEMU disk image using NBD protocol.
   force block driver for format @var{fmt} instead of auto-detecting
 @item -t, --persistent
   don't exit on the last connection
+@item -x NAME, --exportname=NAME
+  set the NDB volume export name. This switches the server to use
+  the new style NBD protocol negotiation
 @item -v, --verbose
   display extra debugging information
 @item -h, --help
-- 
2.5.0