[Qemu-devel] [PATCH 16/19] Add a query-netdev command to QMP

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

This adds a new QMP command called query-netdev to provide information
about the available netdev backends in the QEMU binary. There is no
existing '-netdev ?' support, but if there was, this would obsolete it

The data format looks like

    [
        {
            "name": "user",
            "props": [
                {
                    "name": "type",
                    "help": "net client type (nic, tap etc.)",
                    "type": "string"
                },
                {
                    "name": "name",
                    "help": "identifier for monitor commands",
                    "type": "string"
                },
                {
                    "name": "hostname",
                    "help": "client hostname reported by the builtin DHCP server",
                    "type": "string"
                },
                ...
            ]
        }
        {
            "name": "tap",
            "props": [
                {
                    "name": "type",
                    "help": "net client type (nic, tap etc.)",
                    "type": "string"
                },
                {
                    "name": "ifname",
                    "help": "interface name",
                    "type": "string"
                },
                ...
            ]
        }
        ...
    ]

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
---
 monitor.c     |    8 ++++++++
 net.c         |   49 +++++++++++++++++++++++++++++++++++++++++++++++++
 net.h         |    2 ++
 qemu-option.c |    4 ++++
 qemu-option.h |    4 ++++
 5 files changed, 67 insertions(+), 0 deletions(-)

diff --git a/monitor.c b/monitor.c
index 1c5157d..19f42f3 100644
--- a/monitor.c
+++ b/monitor.c
@@ -2552,6 +2552,14 @@ static const mon_cmd_t info_cmds[] = {
         .mhandler.info_new = do_info_argv,
     },
     {
+        .name       = "netdev",
+        .args_type  = "",
+        .params     = "",
+        .help       = "list valid netdev backend types",
+        .user_print = monitor_user_noop,
+        .mhandler.info_new = do_info_netdev,
+    },
+    {
         .name       = "network",
         .args_type  = "",
         .params     = "",
diff --git a/net.c b/net.c
index 5349001..90929d4 100644
--- a/net.c
+++ b/net.c
@@ -36,6 +36,8 @@
 #include "qemu-common.h"
 #include "qemu_socket.h"
 #include "hw/qdev.h"
+#include "qjson.h"
+#include "qlist.h"
 
 static QTAILQ_HEAD(, VLANState) vlans;
 static QTAILQ_HEAD(, VLANClientState) non_vlan_clients;
@@ -1080,6 +1082,53 @@ static const struct {
 };
 verify(ARRAY_SIZE(net_client_types) == NET_CLIENT_LAST);
 
+
+void do_info_netdev(Monitor *mon, QObject **data)
+{
+    QList *backends = qlist_new();
+    int i, j;
+
+    for (i = 0; i < ARRAY_SIZE(net_client_types) ; i++) {
+	QObject *backend;
+	QList *props = qlist_new();
+
+	if (i == NET_CLIENT_NIC ||
+	    i == NET_CLIENT_DUMP||
+	    i == NET_CLIENT_NONE)
+	    continue;
+
+	for (j = 0 ; net_client_types[i].desc[j].name != NULL ; j++) {
+	    const QemuOptDesc *desc = net_client_types[i].desc + j;
+	    QObject *prop;
+
+	    if (strcmp(desc->name, "vlan") == 0)
+		continue;
+
+	    if (desc->help) {
+		prop = qobject_from_jsonf("{ 'name': %s, 'type': %s, 'help': %s }",
+					  desc->name,
+					  qemu_opt_type_to_string(desc->type),
+					  desc->help);
+	    } else {
+		prop = qobject_from_jsonf("{ 'name': %s, 'type': %s }",
+					  desc->name,
+					  qemu_opt_type_to_string(desc->type));
+	    }
+
+	    qlist_append_obj(props, prop);
+	}
+
+	backend = qobject_from_jsonf("{ 'name': %s, 'props': %p }",
+				     qemu_net_type_to_string(i),
+				     props);
+
+	qlist_append_obj(backends, backend);
+    }
+
+    *data = qobject_from_jsonf("{ 'backends': %p }", backends);
+}
+
+
 int net_client_init(Monitor *mon, QemuOpts *opts, int is_netdev)
 {
     const char *name;
diff --git a/net.h b/net.h
index b83f615..9c0e385 100644
--- a/net.h
+++ b/net.h
@@ -167,6 +167,8 @@ void net_host_device_remove(Monitor *mon, const QDict *qdict);
 int do_netdev_add(Monitor *mon, const QDict *qdict, QObject **ret_data);
 int do_netdev_del(Monitor *mon, const QDict *qdict, QObject **ret_data);
 
+void do_info_netdev(Monitor *mon, QObject **data);
+
 #define DEFAULT_NETWORK_SCRIPT "/etc/qemu-ifup"
 #define DEFAULT_NETWORK_DOWN_SCRIPT "/etc/qemu-ifdown"
 #ifdef __sun__
diff --git a/qemu-option.c b/qemu-option.c
index bb9cc43..f132a9b 100644
--- a/qemu-option.c
+++ b/qemu-option.c
@@ -32,6 +32,10 @@
 #include "qemu-option.h"
 #include "qerror.h"
 
+QEMU_ENUM_IMPL(qemu_opt_type, QEMU_OPT_LAST,
+	       "string", "bool", "number",
+	       "size", "enum");
+
 /*
  * Extracts the name of an option from the parameter string (p points at the
  * first byte of the option name)
diff --git a/qemu-option.h b/qemu-option.h
index 3540a9b..9382cc3 100644
--- a/qemu-option.h
+++ b/qemu-option.h
@@ -28,6 +28,7 @@
 
 #include <stdint.h>
 #include "qemu-queue.h"
+#include "qemu-enum.h"
 #include "qdict.h"
 
 enum QEMUOptionParType {
@@ -90,7 +91,10 @@ enum QemuOptType {
     QEMU_OPT_NUMBER,      /* simple number                                        */
     QEMU_OPT_SIZE,        /* size, accepts (K)ilo, (M)ega, (G)iga, (T)era postfix */
     QEMU_OPT_ENUM,        /* int, from user string validated against an enum      */
+
+    QEMU_OPT_LAST,
 };
+QEMU_ENUM_DECL(qemu_opt_type);
 
 typedef struct QemuOptDesc {
     const char *name;
-- 
1.6.6.1