qemu: command: Format netdev as JSON when QEMU_CAPS_NETDEV_JSON is present

Base the JSON output on a regular capability flag rather than purely
internal flag. This will prepare for the time when QEMU will accept JSON
argumets for -netdev.

For now the capability is not set (thus we for now don't have QMP
schema validation) but that will be addressed later.

To achieve this 'qemuBuildNetdevCommandlineFromJSON' is introduced
and all callers of 'virQEMUBuildNetdevCommandlineFromJSON' are
refactored to use the new helper.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>

src/libvirt_private.syms

@@ -3118,6 +3118,7 @@ virQEMUBuildBufferEscapeComma;
 virQEMUBuildCommandLineJSON;
 virQEMUBuildCommandLineJSONArrayBitmap;
 virQEMUBuildCommandLineJSONArrayNumbered;
+virQEMUBuildCommandLineJSONArrayObjectsStr;
 virQEMUBuildDriveCommandlineFromJSON;
 virQEMUBuildNetdevCommandlineFromJSON;
 

src/qemu/qemu_command.c

@@ -183,6 +183,34 @@ qemuBuildObjectCommandlineFromJSON(virCommand *cmd,
 }
 
 
+static int
+qemuBuildNetdevCommandlineFromJSON(virCommand *cmd,
+                                   virJSONValue *props,
+                                   virQEMUCaps *qemuCaps)
+{
+    g_autofree char *arg = NULL;
+
+    if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_NETDEV_JSON)) {
+        if (!(arg = virJSONValueToString(props, false)))
+            return -1;
+    } else {
+        const char *type = virJSONValueObjectGetString(props, "type");
+        g_auto(virBuffer) buf = VIR_BUFFER_INITIALIZER;
+
+        virBufferAsprintf(&buf, "%s,", type);
+
+        if (virQEMUBuildCommandLineJSON(props, &buf, "type",
+                                        virQEMUBuildCommandLineJSONArrayObjectsStr) < 0)
+            return -1;
+
+        arg = virBufferContentAndReset(&buf);
+    }
+
+    virCommandAddArgList(cmd, "-netdev", arg, NULL);
+    return 0;
+}
+
+
 /**
  * qemuBuildMasterKeyCommandLine:
  * @cmd: the command to modify
@@ -8402,13 +8430,11 @@ qemuBuildInterfaceCommandLine(virQEMUDriver *driver,
                               virNetDevVPortProfileOp vmop,
                               bool standalone,
                               size_t *nnicindexes,
-                              int **nicindexes,
+                              int **nicindexes)
-                              unsigned int flags)
 {
     virDomainDef *def = vm->def;
     int ret = -1;
     g_autofree char *nic = NULL;
-    g_autofree char *host = NULL;
     g_autofree char *chardev = NULL;
     int *tapfd = NULL;
     size_t tapfdSize = 0;
@@ -8662,12 +8688,9 @@ qemuBuildInterfaceCommandLine(virQEMUDriver *driver,
                                              slirpfdName, vdpafdName)))
         goto cleanup;
 
-    if (!(host = virQEMUBuildNetdevCommandlineFromJSON(hostnetprops,
+    if (qemuBuildNetdevCommandlineFromJSON(cmd, hostnetprops, qemuCaps) < 0)
-                                                       (flags & QEMU_BUILD_COMMANDLINE_VALIDATE_KEEP_JSON))))
         goto cleanup;
 
-    virCommandAddArgList(cmd, "-netdev", host, NULL);
-
     /* Possible combinations:
      *
      *   Old way: -netdev type=tap,id=netdev1 \
@@ -8740,8 +8763,7 @@ qemuBuildNetCommandLine(virQEMUDriver *driver,
                         bool standalone,
                         size_t *nnicindexes,
                         int **nicindexes,
-                        unsigned int *bootHostdevNet,
+                        unsigned int *bootHostdevNet)
-                        unsigned int flags)
 {
     size_t i;
     int last_good_net = -1;
@@ -8765,7 +8787,7 @@ qemuBuildNetCommandLine(virQEMUDriver *driver,
             if (qemuBuildInterfaceCommandLine(driver, vm, logManager, secManager, cmd, net,
                                               qemuCaps, bootNet, vmop,
                                               standalone, nnicindexes,
-                                              nicindexes, flags) < 0)
+                                              nicindexes) < 0)
                 goto error;
 
             last_good_net = i;
@@ -9289,8 +9311,7 @@ qemuBuildChannelsCommandLine(virLogManager *logManager,
                              virQEMUDriverConfig *cfg,
                              const virDomainDef *def,
                              virQEMUCaps *qemuCaps,
-                             bool chardevStdioLogd,
+                             bool chardevStdioLogd)
-                             unsigned int flags)
 {
     size_t i;
     unsigned int cdevflags = QEMU_BUILD_CHARDEV_TCP_NOWAIT |
@@ -9302,7 +9323,6 @@ qemuBuildChannelsCommandLine(virLogManager *logManager,
         virDomainChrDef *channel = def->channels[i];
         g_autofree char *chardevstr = NULL;
         g_autoptr(virJSONValue) netdevprops = NULL;
-        g_autofree char *netdevstr = NULL;
 
         if (!(chardevstr = qemuBuildChrChardevStr(logManager, secManager,
                                                   cmd, cfg, def,
@@ -9319,11 +9339,8 @@ qemuBuildChannelsCommandLine(virLogManager *logManager,
             if (!(netdevprops = qemuBuildChannelGuestfwdNetdevProps(channel)))
                 return -1;
 
-            if (!(netdevstr = virQEMUBuildNetdevCommandlineFromJSON(netdevprops,
+            if (qemuBuildNetdevCommandlineFromJSON(cmd, netdevprops, qemuCaps) < 0)
-                                                                    (flags & QEMU_BUILD_COMMANDLINE_VALIDATE_KEEP_JSON))))
                 return -1;
-
-            virCommandAddArgList(cmd, "-netdev", netdevstr, NULL);
             break;
 
         case VIR_DOMAIN_CHR_CHANNEL_TARGET_TYPE_VIRTIO:
@@ -10471,7 +10488,7 @@ qemuBuildCommandLine(virQEMUDriver *driver,
 
     if (qemuBuildNetCommandLine(driver, vm, logManager, secManager, cmd,
                                 qemuCaps, vmop, standalone,
-                                nnicindexes, nicindexes, &bootHostdevNet, flags) < 0)
+                                nnicindexes, nicindexes, &bootHostdevNet) < 0)
         return NULL;
 
     if (qemuBuildSmartcardCommandLine(logManager, secManager, cmd, cfg, def, qemuCaps,
@@ -10487,7 +10504,7 @@ qemuBuildCommandLine(virQEMUDriver *driver,
         return NULL;
 
     if (qemuBuildChannelsCommandLine(logManager, secManager, cmd, cfg, def, qemuCaps,
-                                     chardevStdioLogd, flags) < 0)
+                                     chardevStdioLogd) < 0)
         return NULL;
 
     if (qemuBuildConsoleCommandLine(logManager, secManager, cmd, cfg, def, qemuCaps,

src/util/virqemu.c

@@ -127,7 +127,7 @@ virQEMUBuildCommandLineJSONArrayNumbered(const char *key,
  *
  *  guestfwd=tcp:10.0.2.1:4600-chardev:charchannel0,guestfwd=...
  */
-static int
+int
 virQEMUBuildCommandLineJSONArrayObjectsStr(const char *key,
                                            virJSONValue *array,
                                            virBuffer *buf,

src/util/virqemu.h

@@ -30,6 +30,10 @@ typedef int (*virQEMUBuildCommandLineJSONArrayFormatFunc)(const char *key,
                                                           virJSONValue *array,
                                                           virBuffer *buf,
                                                           const char *skipKey);
+int virQEMUBuildCommandLineJSONArrayObjectsStr(const char *key,
+                                               virJSONValue *array,
+                                               virBuffer *buf,
+                                               const char *skipKey);
 int virQEMUBuildCommandLineJSONArrayBitmap(const char *key,
                                            virJSONValue *array,
                                            virBuffer *buf,