virnetmessage: Introduce virNetMessageClearFDs

The helper splits out the clearing of the FDs transacted inside a
virNetMessage.

APIs transacting FDs both from and to the client at the same time will
need to clear the FDs stored in virNetMessage as the structure is
re-used for the reply and without clearing the list of FDs we'd return
the FDs sent by the client in addition to the new FDs sent by the API.t

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>

src/libvirt_remote.syms

@@ -102,6 +102,7 @@ virNetDaemonUpdateServices;
 # rpc/virnetmessage.h
 virNetMessageAddFD;
 virNetMessageClear;
+virNetMessageClearFDs;
 virNetMessageClearPayload;
 virNetMessageDecodeHeader;
 virNetMessageDecodeLength;

src/rpc/virnetmessage.c

@@ -48,7 +48,7 @@ virNetMessage *virNetMessageNew(bool tracked)
 
 
 void
-virNetMessageClearPayload(virNetMessage *msg)
+virNetMessageClearFDs(virNetMessage *msg)
 {
     size_t i;
 
@@ -58,6 +58,13 @@ virNetMessageClearPayload(virNetMessage *msg)
     msg->donefds = 0;
     msg->nfds = 0;
     VIR_FREE(msg->fds);
+}
+
+
+void
+virNetMessageClearPayload(virNetMessage *msg)
+{
+    virNetMessageClearFDs(msg);
 
     msg->bufferOffset = 0;
     msg->bufferLength = 0;

src/rpc/virnetmessage.h

@@ -49,6 +49,7 @@ struct _virNetMessage {
 
 virNetMessage *virNetMessageNew(bool tracked);
 
+void virNetMessageClearFDs(virNetMessage *msg);
 void virNetMessageClearPayload(virNetMessage *msg);
 
 void virNetMessageClear(virNetMessage *);