[Qemu-block] [PATCH v3 for-2.9 8/9] nbd: Tidy up blockdev-add interface

[Markus Armbruster]

SocketAddress is a simple union, and simple unions are awkward: they
have their variant members wrapped in a "data" object on the wire, and
require additional indirections in C.  I intend to limit its use to
existing external interfaces, and convert all internal interfaces to
SocketAddressFlat.

BlockdevOptionsNbd is an external interface using SocketAddress.  We
already use SocketAddressFlat elsewhere in blockdev=add.  Replace it
by SocketAddressFlat while we can (it's new in 2.9) for simplicity and
consistency.  For example,

    { "execute": "blockdev-add",
      "arguments": { "node-name": "foo", "driver": "nbd",
                     "server": { "type": "inet",
                                 "data": { "host": "localhost",
                                           "port": "12345" } } } }

becomes

    { "execute": "blockdev-add",
      "arguments": { "node-name": "foo", "driver": "nbd",
                     "server": { "type": "inet",
                                 "host": "localhost", "port": "12345" } } }

Since the internal interfaces still take SocketAddress, this requires
conversion function socket_address_crumple().  It'll go away when I
update the interfaces.

Unfortunately, SocketAddress is also visible in -drive since 2.8:

    -drive 
if=none,driver=nbd,server.type=inet,server.data.host=127.0.0.1,server.data.port=12345

Nobody should be using it, as it's fairly new and has never been
documented, so adding still more compatibility gunk to keep it working
isn't worth the trouble.  You now have to use

    -drive 
if=none,driver=nbd,server.type=inet,server.host=127.0.0.1,server.port=12345

Signed-off-by: Markus Armbruster <address@hidden>
Reviewed-by: Eric Blake <address@hidden>
Reviewed-by: Max Reitz <address@hidden>
---
 block/nbd.c          | 53 +++++++++++++++++++++++++++-------------------------
 qapi/block-core.json |  2 +-
 2 files changed, 29 insertions(+), 26 deletions(-)

diff --git a/block/nbd.c b/block/nbd.c
index 11e3ba7..8bb29a9 100644
--- a/block/nbd.c
+++ b/block/nbd.c
@@ -47,7 +47,7 @@ typedef struct BDRVNBDState {
     NBDClientSession client;
 
     /* For nbd_refresh_filename() */
-    SocketAddress *saddr;
+    SocketAddressFlat *saddr;
     char *export, *tlscredsid;
 } BDRVNBDState;
 
@@ -95,7 +95,7 @@ static int nbd_parse_uri(const char *filename, QDict *options)
             goto out;
         }
         qdict_put(options, "server.type", qstring_from_str("unix"));
-        qdict_put(options, "server.data.path",
+        qdict_put(options, "server.path",
                   qstring_from_str(qp->p[0].value));
     } else {
         QString *host;
@@ -116,10 +116,10 @@ static int nbd_parse_uri(const char *filename, QDict 
*options)
         }
 
         qdict_put(options, "server.type", qstring_from_str("inet"));
-        qdict_put(options, "server.data.host", host);
+        qdict_put(options, "server.host", host);
 
         port_str = g_strdup_printf("%d", uri->port ?: NBD_DEFAULT_PORT);
-        qdict_put(options, "server.data.port", qstring_from_str(port_str));
+        qdict_put(options, "server.port", qstring_from_str(port_str));
         g_free(port_str);
     }
 
@@ -197,7 +197,7 @@ static void nbd_parse_filename(const char *filename, QDict 
*options,
     /* are we a UNIX or TCP socket? */
     if (strstart(host_spec, "unix:", &unixpath)) {
         qdict_put(options, "server.type", qstring_from_str("unix"));
-        qdict_put(options, "server.data.path", qstring_from_str(unixpath));
+        qdict_put(options, "server.path", qstring_from_str(unixpath));
     } else {
         InetSocketAddress *addr = NULL;
 
@@ -207,8 +207,8 @@ static void nbd_parse_filename(const char *filename, QDict 
*options,
         }
 
         qdict_put(options, "server.type", qstring_from_str("inet"));
-        qdict_put(options, "server.data.host", qstring_from_str(addr->host));
-        qdict_put(options, "server.data.port", qstring_from_str(addr->port));
+        qdict_put(options, "server.host", qstring_from_str(addr->host));
+        qdict_put(options, "server.port", qstring_from_str(addr->port));
         qapi_free_InetSocketAddress(addr);
     }
 
@@ -248,20 +248,21 @@ static bool nbd_process_legacy_socket_options(QDict 
*output_options,
         }
 
         qdict_put(output_options, "server.type", qstring_from_str("unix"));
-        qdict_put(output_options, "server.data.path", qstring_from_str(path));
+        qdict_put(output_options, "server.path", qstring_from_str(path));
     } else if (host) {
         qdict_put(output_options, "server.type", qstring_from_str("inet"));
-        qdict_put(output_options, "server.data.host", qstring_from_str(host));
-        qdict_put(output_options, "server.data.port",
+        qdict_put(output_options, "server.host", qstring_from_str(host));
+        qdict_put(output_options, "server.port",
                   qstring_from_str(port ?: stringify(NBD_DEFAULT_PORT)));
     }
 
     return true;
 }
 
-static SocketAddress *nbd_config(BDRVNBDState *s, QDict *options, Error **errp)
+static SocketAddressFlat *nbd_config(BDRVNBDState *s, QDict *options,
+                                     Error **errp)
 {
-    SocketAddress *saddr = NULL;
+    SocketAddressFlat *saddr = NULL;
     QDict *addr = NULL;
     QObject *crumpled_addr = NULL;
     Visitor *iv = NULL;
@@ -287,7 +288,7 @@ static SocketAddress *nbd_config(BDRVNBDState *s, QDict 
*options, Error **errp)
      * visitor expects the former.
      */
     iv = qobject_input_visitor_new(crumpled_addr);
-    visit_type_SocketAddress(iv, NULL, &saddr, &local_err);
+    visit_type_SocketAddressFlat(iv, NULL, &saddr, &local_err);
     if (local_err) {
         error_propagate(errp, local_err);
         goto done;
@@ -306,9 +307,10 @@ NBDClientSession *nbd_get_client_session(BlockDriverState 
*bs)
     return &s->client;
 }
 
-static QIOChannelSocket *nbd_establish_connection(SocketAddress *saddr,
+static QIOChannelSocket *nbd_establish_connection(SocketAddressFlat 
*saddr_flat,
                                                   Error **errp)
 {
+    SocketAddress *saddr = socket_address_crumple(saddr_flat);
     QIOChannelSocket *sioc;
     Error *local_err = NULL;
 
@@ -318,6 +320,7 @@ static QIOChannelSocket 
*nbd_establish_connection(SocketAddress *saddr,
     qio_channel_socket_connect_sync(sioc,
                                     saddr,
                                     &local_err);
+    qapi_free_SocketAddress(saddr);
     if (local_err) {
         error_propagate(errp, local_err);
         return NULL;
@@ -409,7 +412,7 @@ static int nbd_open(BlockDriverState *bs, QDict *options, 
int flags,
         goto error;
     }
 
-    /* Translate @host, @port, and @path to a SocketAddress */
+    /* Translate @host, @port, and @path to a SocketAddressFlat */
     if (!nbd_process_legacy_socket_options(options, opts, errp)) {
         goto error;
     }
@@ -430,11 +433,11 @@ static int nbd_open(BlockDriverState *bs, QDict *options, 
int flags,
         }
 
         /* TODO SOCKET_ADDRESS_KIND_FD where fd has AF_INET or AF_INET6 */
-        if (s->saddr->type != SOCKET_ADDRESS_KIND_INET) {
+        if (s->saddr->type != SOCKET_ADDRESS_FLAT_TYPE_INET) {
             error_setg(errp, "TLS only supported over IP sockets");
             goto error;
         }
-        hostname = s->saddr->u.inet.data->host;
+        hostname = s->saddr->u.inet.host;
     }
 
     /* establish TCP connection, return error if it fails
@@ -457,7 +460,7 @@ static int nbd_open(BlockDriverState *bs, QDict *options, 
int flags,
         object_unref(OBJECT(tlscreds));
     }
     if (ret < 0) {
-        qapi_free_SocketAddress(s->saddr);
+        qapi_free_SocketAddressFlat(s->saddr);
         g_free(s->export);
         g_free(s->tlscredsid);
     }
@@ -483,7 +486,7 @@ static void nbd_close(BlockDriverState *bs)
 
     nbd_client_close(bs);
 
-    qapi_free_SocketAddress(s->saddr);
+    qapi_free_SocketAddressFlat(s->saddr);
     g_free(s->export);
     g_free(s->tlscredsid);
 }
@@ -514,15 +517,15 @@ static void nbd_refresh_filename(BlockDriverState *bs, 
QDict *options)
     Visitor *ov;
     const char *host = NULL, *port = NULL, *path = NULL;
 
-    if (s->saddr->type == SOCKET_ADDRESS_KIND_INET) {
-        const InetSocketAddress *inet = s->saddr->u.inet.data;
+    if (s->saddr->type == SOCKET_ADDRESS_FLAT_TYPE_INET) {
+        const InetSocketAddress *inet = &s->saddr->u.inet;
         if (!inet->has_ipv4 && !inet->has_ipv6 && !inet->has_to) {
             host = inet->host;
             port = inet->port;
         }
-    } else if (s->saddr->type == SOCKET_ADDRESS_KIND_UNIX) {
-        path = s->saddr->u.q_unix.data->path;
-    }
+    } else if (s->saddr->type == SOCKET_ADDRESS_FLAT_TYPE_UNIX) {
+        path = s->saddr->u.q_unix.path;
+    } /* else can't represent as pseudo-filename */
 
     qdict_put(opts, "driver", qstring_from_str("nbd"));
 
@@ -541,7 +544,7 @@ static void nbd_refresh_filename(BlockDriverState *bs, 
QDict *options)
     }
 
     ov = qobject_output_visitor_new(&saddr_qdict);
-    visit_type_SocketAddress(ov, NULL, &s->saddr, &error_abort);
+    visit_type_SocketAddressFlat(ov, NULL, &s->saddr, &error_abort);
     visit_complete(ov, &saddr_qdict);
     visit_free(ov);
     qdict_put_obj(opts, "server", saddr_qdict);
diff --git a/qapi/block-core.json b/qapi/block-core.json
index 4e8e4e3..8d87962 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -2762,7 +2762,7 @@
 # Since: 2.9
 ##
 { 'struct': 'BlockdevOptionsNbd',
-  'data': { 'server': 'SocketAddress',
+  'data': { 'server': 'SocketAddressFlat',
             '*export': 'str',
             '*tls-creds': 'str' } }
 
-- 
2.7.4