Removing probing of secondary drivers

For stateless, client side drivers, it is never correct to
probe for secondary drivers. It is only ever appropriate to
use the secondary driver that is associated with the
hypervisor in question. As a result the ESX & HyperV drivers
have both been forced to do hacks where they register no-op
drivers for the ones they don't implement.

For stateful, server side drivers, we always just want to
use the same built-in shared driver. The exception is
virtualbox which is really a stateless driver and so wants
to use its own server side secondary drivers. To deal with
this virtualbox has to be built as 3 separate loadable
modules to allow registration to work in the right order.

This can all be simplified by introducing a new struct
recording the precise set of secondary drivers each
hypervisor driver wants

struct _virConnectDriver {
    virHypervisorDriverPtr hypervisorDriver;
    virInterfaceDriverPtr interfaceDriver;
    virNetworkDriverPtr networkDriver;
    virNodeDeviceDriverPtr nodeDeviceDriver;
    virNWFilterDriverPtr nwfilterDriver;
    virSecretDriverPtr secretDriver;
    virStorageDriverPtr storageDriver;
};

Instead of registering the hypervisor driver, we now
just register a virConnectDriver instead. This allows
us to remove all probing of secondary drivers. Once we
have chosen the primary driver, we immediately know the
correct secondary drivers to use.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>

src/network/bridge_driver.c

@@ -2514,23 +2514,6 @@ static virNetworkPtr networkLookupByName(virConnectPtr conn,
     return ret;
 }
 
-static virDrvOpenStatus networkOpen(virConnectPtr conn ATTRIBUTE_UNUSED,
-                                    virConnectAuthPtr auth ATTRIBUTE_UNUSED,
-                                    unsigned int flags)
-{
-    virCheckFlags(VIR_CONNECT_RO, VIR_DRV_OPEN_ERROR);
-
-    if (!driver)
-        return VIR_DRV_OPEN_DECLINED;
-
-    return VIR_DRV_OPEN_SUCCESS;
-}
-
-static int networkClose(virConnectPtr conn ATTRIBUTE_UNUSED)
-{
-    return 0;
-}
-
 static int networkConnectNumOfNetworks(virConnectPtr conn)
 {
     int nactive = 0;
@@ -3670,9 +3653,7 @@ networkGetDHCPLeases(virNetworkPtr network,
 
 
 static virNetworkDriver networkDriver = {
-    "Network",
-    .networkOpen = networkOpen, /* 0.2.0 */
-    .networkClose = networkClose, /* 0.2.0 */
+    .name = "bridge",
     .connectNumOfNetworks = networkConnectNumOfNetworks, /* 0.2.0 */
     .connectListNetworks = networkConnectListNetworks, /* 0.2.0 */
     .connectNumOfDefinedNetworks = networkConnectNumOfDefinedNetworks, /* 0.2.0 */
@@ -3698,7 +3679,7 @@ static virNetworkDriver networkDriver = {
 };
 
 static virStateDriver networkStateDriver = {
-    .name = "Network",
+    .name = "bridge",
     .stateInitialize  = networkStateInitialize,
     .stateAutoStart  = networkStateAutoStart,
     .stateCleanup = networkStateCleanup,
@@ -3707,7 +3688,7 @@ static virStateDriver networkStateDriver = {
 
 int networkRegister(void)
 {
-    if (virRegisterNetworkDriver(&networkDriver) < 0)
+    if (virSetSharedNetworkDriver(&networkDriver) < 0)
         return -1;
     if (virRegisterStateDriver(&networkStateDriver) < 0)
         return -1;