[libvirt] [PATCH 1/3] Debug: Add WARN'ing messages for when a client has opened/closed connection.

[Prerna Saxena]

While tracing connections from a remote client, it helps to keep track
of the connection lifecycle. Messages such as the following :

error : virNetSocketReadWire:1574 : End of file while reading data: Input/output error

are rather unhelpful. They do not indicate if the client had earlier asked for
connection closure via libvirt API.
This patch introduces messages to annotate when a client connected/disconnected.

Signed-off-by: Prerna Saxena <saxenap.ltc at gmail.com>
---
 src/rpc/virnetserverclient.c | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/src/rpc/virnetserverclient.c b/src/rpc/virnetserverclient.c
index 85857bc..a77feaa 100644
--- a/src/rpc/virnetserverclient.c
+++ b/src/rpc/virnetserverclient.c
@@ -678,14 +678,19 @@ int virNetServerClientGetTLSKeySize(virNetServerClientPtr client)
     return size;
 }
 #endif
-
+/*
+ * This mostly just needs to publish the client socket FD to logs.
+ * It does not necessarily need a lock, or will add lock contention problems.
+ * Replace the lock with a reference counting mechanism, to prevent the client
+ * object from being deallocated while this is being run
+ */
 int virNetServerClientGetFD(virNetServerClientPtr client)
 {
     int fd = -1;
-    virObjectLock(client);
+    virObjectRef(client);
     if (client->sock)
         fd = virNetSocketGetFD(client->sock);
-    virObjectUnlock(client);
+    virObjectUnref(client);
     return fd;
 }
 
@@ -965,7 +970,9 @@ void virNetServerClientClose(virNetServerClientPtr client)
     virKeepAlivePtr ka;
 
     virObjectLock(client);
-    VIR_DEBUG("client=%p", client);
+    VIR_WARN("Free'ing up resources for client=%p sock=%d", client,
+               virNetServerClientGetFD(client));
+
     if (!client->sock) {
         virObjectUnlock(client);
         return;
@@ -1039,6 +1046,8 @@ void virNetServerClientDelayedClose(virNetServerClientPtr client)
     virObjectLock(client);
     client->delayedClose = true;
     virObjectUnlock(client);
+    VIR_WARN("Client=%p sock=%d requested closure of connection.",
+              client, virNetServerClientGetFD(client));
 }
 
 void virNetServerClientImmediateClose(virNetServerClientPtr client)
@@ -1151,6 +1160,7 @@ static void virNetServerClientDispatchRead(virNetServerClientPtr client)
     if (client->rx->nfds == 0) {
         if (virNetServerClientRead(client) < 0) {
             client->wantClose = true;
+            VIR_WARN("Client=%p sock=%p closed connection", client, client->sock);
             return; /* Error */
         }
     }
-- 
1.8.1.2