Allow sync IO and keepalives to be skipped in RPC client setup

Currently the virNetClientPtr constructor will always register
the async IO event handler and the keepalive objects. In the
case of the lock manager, there will be no event loop available
nor keepalive support required. Split this setup out of the
constructor and into separate methods.

The remote driver will enable async IO and keepalives, while
the LXC driver will only enable async IO

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

diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 0d7c9757b764aec9c103ec6f1eb236d47309bd2f..a859810a2ce0adfb6146086705519a3f1fe2e551 100644 (file)
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -1322,6 +1322,8 @@ virNetClientNewExternal;
 virNetClientNewSSH;
 virNetClientNewTCP;
 virNetClientNewUNIX;
+virNetClientRegisterAsyncIO;
+virNetClientRegisterKeepAlive;
 virNetClientRemoteAddrString;
 virNetClientRemoveStream;
 virNetClientSendNoReply;

diff --git a/src/lxc/lxc_monitor.c b/src/lxc/lxc_monitor.c
index a81d0f7778e04582a364ce011f3902bf99beb506..53ecd6077359e419f10a4add7b073de3c7c252a9 100644 (file)
--- a/src/lxc/lxc_monitor.c
+++ b/src/lxc/lxc_monitor.c
@@ -129,6 +129,8 @@ virLXCMonitorPtr virLXCMonitorNew(virDomainObjPtr vm,
     if (!(mon->client = virNetClientNewUNIX(sockpath, false, NULL)))
         goto error;
 
+    if (virNetClientRegisterAsyncIO(mon->client) < 0)
+        goto error;
 
     if (!(mon->program = virNetClientProgramNew(VIR_LXC_PROTOCOL_PROGRAM,
                                                 VIR_LXC_PROTOCOL_PROGRAM_VERSION,

diff --git a/src/remote/remote_driver.c b/src/remote/remote_driver.c
index 8153d70da54f430c8da3bf5b4a5bd232701958db..c4941c537882018b6a4a11695694e8650e60c77c 100644 (file)
--- a/src/remote/remote_driver.c
+++ b/src/remote/remote_driver.c
@@ -686,6 +686,15 @@ doRemoteOpen(virConnectPtr conn,
     } /* switch (transport) */
 
 
+    if (virNetClientRegisterAsyncIO(priv->client) < 0) {
+        VIR_DEBUG("Failed to add event watch, disabling events and support for"
+                  " keepalive messages");
+        virResetLastError();
+    } else {
+        if (virNetClientRegisterKeepAlive(priv->client) < 0)
+            goto failed;
+    }
+
     virNetClientSetCloseCallback(priv->client,
                                  remoteClientCloseFunc,
                                  conn, NULL);

diff --git a/src/rpc/virnetclient.c b/src/rpc/virnetclient.c
index 42bdc54d45f507b86b130dadde4068c050b7cd8c..cec5efbba6d0cc8920a617a5966733d32eb9b374 100644 (file)
--- a/src/rpc/virnetclient.c
+++ b/src/rpc/virnetclient.c
@@ -68,6 +68,7 @@ struct _virNetClient {
     virMutex lock;
 
     virNetSocketPtr sock;
+    bool asyncIO;
 
     virNetTLSSessionPtr tls;
     char *hostname;
@@ -309,7 +310,6 @@ static virNetClientPtr virNetClientNew(virNetSocketPtr sock,
 {
     virNetClientPtr client = NULL;
     int wakeupFD[2] = { -1, -1 };
-    virKeepAlivePtr ka = NULL;
 
     if (virNetClientInitialize() < 0)
         return NULL;
@@ -337,29 +337,6 @@ static virNetClientPtr virNetClientNew(virNetSocketPtr sock,
         !(client->hostname = strdup(hostname)))
         goto no_memory;
 
-    /* Set up a callback to listen on the socket data */
-    virObjectRef(client);
-    if (virNetSocketAddIOCallback(client->sock,
-                                  VIR_EVENT_HANDLE_READABLE,
-                                  virNetClientIncomingEvent,
-                                  client,
-                                  virObjectFreeCallback) < 0) {
-        virObjectUnref(client);
-        VIR_DEBUG("Failed to add event watch, disabling events and support for"
-                  " keepalive messages");
-    } else {
-        /* Keepalive protocol consists of async messages so it can only be used
-         * if the client supports them */
-        if (!(ka = virKeepAliveNew(-1, 0, client,
-                                   virNetClientKeepAliveSendCB,
-                                   virNetClientKeepAliveDeadCB,
-                                   virObjectFreeCallback)))
-            goto error;
-        /* keepalive object has a reference to client */
-        virObjectRef(client);
-    }
-
-    client->keepalive = ka;
     PROBE(RPC_CLIENT_NEW,
           "client=%p sock=%p",
           client, client->sock);
@@ -370,10 +347,6 @@ no_memory:
 error:
     VIR_FORCE_CLOSE(wakeupFD[0]);
     VIR_FORCE_CLOSE(wakeupFD[1]);
-    if (ka) {
-        virKeepAliveStop(ka);
-        virObjectUnref(ka);
-    }
     virObjectUnref(client);
     return NULL;
 }
@@ -433,6 +406,58 @@ virNetClientPtr virNetClientNewExternal(const char **cmdargv)
 }
 
 
+int virNetClientRegisterAsyncIO(virNetClientPtr client)
+{
+    if (client->asyncIO)
+        return 0;
+
+    /* Set up a callback to listen on the socket data */
+    virObjectRef(client);
+    if (virNetSocketAddIOCallback(client->sock,
+                                  VIR_EVENT_HANDLE_READABLE,
+                                  virNetClientIncomingEvent,
+                                  client,
+                                  virObjectFreeCallback) < 0) {
+        virObjectUnref(client);
+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                       _("Unable to register async IO callback"));
+        return -1;
+    }
+
+    client->asyncIO = true;
+    return 0;
+}
+
+
+int virNetClientRegisterKeepAlive(virNetClientPtr client)
+{
+    virKeepAlivePtr ka;
+
+    if (client->keepalive)
+        return 0;
+
+    if (!client->asyncIO) {
+        virReportError(VIR_ERR_OPERATION_INVALID, "%s",
+                       _("Unable to enable keepalives without async IO support"));
+        return -1;
+    }
+
+    /* Keepalive protocol consists of async messages so it can only be used
+     * if the client supports them */
+    if (!(ka = virKeepAliveNew(-1, 0, client,
+                               virNetClientKeepAliveSendCB,
+                               virNetClientKeepAliveDeadCB,
+                               virObjectFreeCallback)))
+        return -1;
+
+    /* keepalive object has a reference to client */
+    virObjectRef(client);
+
+    client->keepalive = ka;
+    return 0;
+}
+
+
 int virNetClientGetFD(virNetClientPtr client)
 {
     int fd;

diff --git a/src/rpc/virnetclient.h b/src/rpc/virnetclient.h
index d6b9b3c1d62a960051c1853be9511a44b2d27638..3d55a74e05e6084de178629b6dc72ff0cd562a42 100644 (file)
--- a/src/rpc/virnetclient.h
+++ b/src/rpc/virnetclient.h
@@ -52,6 +52,9 @@ virNetClientPtr virNetClientNewSSH(const char *nodename,
 
 virNetClientPtr virNetClientNewExternal(const char **cmdargv);
 
+int virNetClientRegisterAsyncIO(virNetClientPtr client);
+int virNetClientRegisterKeepAlive(virNetClientPtr client);
+
 typedef void (*virNetClientCloseFunc)(virNetClientPtr client,
                                       int reason,
                                       void *opaque);