[RFC PATCH 06/18] qemu-storage-daemon: Add --nbd-server option

[Kevin Wolf <kwolf@redhat.com>]

Add a --nbd-server option to qemu-storage-daemon to start the built-in
NBD server right away. It maps the arguments for nbd-server-start to the
command line. Example (only with required options):

    --nbd-server addr.type=inet,addr.host=localhost,addr.port=10809

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 qapi/block.json       | 18 ++++++++++++++++++
 include/block/nbd.h   |  1 +
 blockdev-nbd.c        |  5 +++++
 qemu-storage-daemon.c | 26 +++++++++++++++++++++++++-
 Makefile.objs         |  2 +-
 5 files changed, 50 insertions(+), 2 deletions(-)

diff --git a/qapi/block.json b/qapi/block.json
index 145c268bb6..7fe0cf6538 100644
--- a/qapi/block.json
+++ b/qapi/block.json
@@ -215,6 +215,24 @@
             '*id': 'str',
             '*force': 'bool' } }
 
+##
+# @NbdServerOptions:
+#
+# @addr: Address on which to listen.
+# @tls-creds: ID of the TLS credentials object (since 2.6).
+# @tls-authz: ID of the QAuthZ authorization object used to validate
+#             the client's x509 distinguished name. This object is
+#             is only resolved at time of use, so can be deleted and
+#             recreated on the fly while the NBD server is active.
+#             If missing, it will default to denying access (since 4.0).
+#
+# Since: 4.2
+##
+{ 'struct': 'NbdServerOptions',
+  'data': { 'addr': 'SocketAddress',
+            '*tls-creds': 'str',
+            '*tls-authz': 'str'} }
+
 ##
 # @nbd-server-start:
 #
diff --git a/include/block/nbd.h b/include/block/nbd.h
index 316fd705a9..2a7441491a 100644
--- a/include/block/nbd.h
+++ b/include/block/nbd.h
@@ -353,6 +353,7 @@ void nbd_client_put(NBDClient *client);
 
 void nbd_server_start(SocketAddress *addr, const char *tls_creds,
                       const char *tls_authz, Error **errp);
+void nbd_server_start_options(NbdServerOptions *arg, Error **errp);
 
 /* nbd_read
  * Reads @size bytes from @ioc. Returns 0 on success.
diff --git a/blockdev-nbd.c b/blockdev-nbd.c
index 6a8b206e1d..d4c1fd4166 100644
--- a/blockdev-nbd.c
+++ b/blockdev-nbd.c
@@ -132,6 +132,11 @@ void nbd_server_start(SocketAddress *addr, const char *tls_creds,
     nbd_server = NULL;
 }
 
+void nbd_server_start_options(NbdServerOptions *arg, Error **errp)
+{
+    nbd_server_start(arg->addr, arg->tls_creds, arg->tls_authz, errp);
+}
+
 void qmp_nbd_server_start(SocketAddressLegacy *addr,
                           bool has_tls_creds, const char *tls_creds,
                           bool has_tls_authz, const char *tls_authz,
diff --git a/qemu-storage-daemon.c b/qemu-storage-daemon.c
index 904e3c3a46..51882452f3 100644
--- a/qemu-storage-daemon.c
+++ b/qemu-storage-daemon.c
@@ -25,11 +25,14 @@
 #include "qemu/osdep.h"
 
 #include "block/block.h"
+#include "block/nbd.h"
 #include "crypto/init.h"
 
 #include "qapi/error.h"
-#include "qapi/qapi-visit-block-core.h"
+#include "qapi/qapi-commands-block.h"
 #include "qapi/qapi-commands-block-core.h"
+#include "qapi/qapi-visit-block.h"
+#include "qapi/qapi-visit-block-core.h"
 #include "qapi/qobject-input-visitor.h"
 
 #include "qemu-common.h"
@@ -64,6 +67,12 @@ static void help(void)
 "             [,driver specific parameters...]\n"
 "                         configure a block backend\n"
 "\n"
+"  --nbd-server addr.type=inet,addr.host=<host>,addr.port=<port>\n"
+"               [,tls-creds=<id>][,tls-authz=<id>]\n"
+"  --nbd-server addr.type=unix,addr.path=<path>\n"
+"               [,tls-creds=<id>][,tls-authz=<id>]\n"
+"                         start an NBD server for exporting block nodes\n"
+"\n"
 "  --object <properties>  define a QOM object such as 'secret' for\n"
 "                         passwords and/or encryption keys\n"
 "\n"
@@ -74,6 +83,7 @@ QEMU_HELP_BOTTOM "\n",
 enum {
     OPTION_OBJECT = 256,
     OPTION_BLOCKDEV,
+    OPTION_NBD_SERVER,
 };
 
 static QemuOptsList qemu_object_opts = {
@@ -95,6 +105,7 @@ static int process_options(int argc, char *argv[], Error **errp)
         {"help", no_argument, 0, 'h'},
         {"object", required_argument, 0, OPTION_OBJECT},
         {"blockdev", required_argument, 0, OPTION_BLOCKDEV},
+        {"nbd-server", required_argument, 0, OPTION_NBD_SERVER},
         {"version", no_argument, 0, 'V'},
         {"trace", required_argument, NULL, 'T'},
         {0, 0, 0, 0}
@@ -152,6 +163,19 @@ static int process_options(int argc, char *argv[], Error **errp)
                 qapi_free_BlockdevOptions(options);
                 break;
             }
+        case OPTION_NBD_SERVER:
+            {
+                Visitor *v;
+                NbdServerOptions *options;
+
+                v = qobject_input_visitor_new_str(optarg, NULL, &error_fatal);
+                visit_type_NbdServerOptions(v, NULL, &options, &error_fatal);
+                visit_free(v);
+
+                nbd_server_start_options(options, &error_fatal);
+                qapi_free_NbdServerOptions(options);
+                break;
+            }
         }
     }
     if (optind != argc) {
diff --git a/Makefile.objs b/Makefile.objs
index 00fdf54500..cc262e445f 100644
--- a/Makefile.objs
+++ b/Makefile.objs
@@ -42,7 +42,7 @@ io-obj-y = io/
 # used for system emulation, too, but specified separately there)
 
 storage-daemon-obj-y = block/
-storage-daemon-obj-y += blockdev.o iothread.o
+storage-daemon-obj-y += blockdev.o blockdev-nbd.o iothread.o
 
 ######################################################################
 # Target independent part of system emulation. The long term path is to
-- 
2.20.1