monitor: Improve host_net_add (Jan Kiszka)

Fix the documentation of the host_net_add monitor command and allow the
user to pass no options at all. Moreover, inform the user on the
monitor terminal if a request failed.
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>


git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@7201 c046a42c-6fe2-441c-8c8c-71466251a162

monitor.c

@@ -1730,8 +1730,8 @@ static const mon_cmd_t mon_cmds[] = {
                                         "add drive to PCI storage controller" },
     { "pci_add", "sss", pci_device_hot_add, "pci_addr=auto|[[<domain>:]<bus>:]<slot> nic|storage [[vlan=n][,macaddr=addr][,model=type]] [file=file][,if=type][,bus=nr]...", "hot-add PCI device" },
     { "pci_del", "s", pci_device_hot_remove, "pci_addr=[[<domain>:]<bus>:]<slot>", "hot remove PCI device" },
-    { "host_net_add", "ss", net_host_device_add,
-      "[tap,user,socket,vde,dump] options", "add host VLAN client" },
+    { "host_net_add", "ss?", net_host_device_add,
+      "tap|user|socket|vde|dump [options]", "add host VLAN client" },
     { "host_net_remove", "is", net_host_device_remove,
       "vlan_id name", "remove host VLAN client" },
 #endif

net.c

@@ -2042,7 +2042,9 @@ void net_host_device_add(Monitor *mon, const char *device, const char *opts)
         monitor_printf(mon, "invalid host network device %s\n", device);
         return;
     }
-    net_client_init(device, opts);
+    if (net_client_init(device, opts ? : "") < 0) {
+        monitor_printf(mon, "adding host network device %s failed\n", device);
+    }
 }
 
 void net_host_device_remove(Monitor *mon, int vlan_id, const char *device)