[libvirt] [PATCH 2/4] Try harder to send RPC error message back to client
When failing to serialize the normal RPC reply, try harder to
send a error message back to the client, instead of immediately
closing the connection.
* daemon/dispatch.c: Improve error messages when RPC reply
can not be sent
---
daemon/dispatch.c | 47 +++++++++++++++++++++++++++++------------------
1 files changed, 29 insertions(+), 18 deletions(-)
diff --git a/daemon/dispatch.c b/daemon/dispatch.c
index d6c2eb1..22eef36 100644
--- a/daemon/dispatch.c
+++ b/daemon/dispatch.c
@@ -548,7 +548,8 @@ remoteDispatchClientCall (struct qemud_server *server,
if (remoteEncodeClientMessageHeader(msg) < 0) {
xdr_free (data->ret_filter, (char*)&ret);
- goto fatal_error;
+ remoteDispatchFormatError(&rerr, "%s", _("failed to serialize
reply header"));
+ goto xdr_hdr_error;
}
@@ -558,22 +559,30 @@ remoteDispatchClientCall (struct qemud_server *server,
msg->bufferLength,
XDR_ENCODE);
- if (xdr_setpos(&xdr, msg->bufferOffset) == 0)
- goto xdr_error;
+ if (xdr_setpos(&xdr, msg->bufferOffset) == 0) {
+ remoteDispatchFormatError(&rerr, "%s", _("failed to change XDR
reply offset"));
+ goto xdr_error;
+ }
/* If OK, serialise return structure, if error serialise error. */
/* Serialise reply data */
- if (!((data->ret_filter) (&xdr, &ret)))
+ if (!((data->ret_filter) (&xdr, &ret))) {
+ remoteDispatchFormatError(&rerr, "%s", _("failed to serialize
reply payload (probable message size limit)"));
goto xdr_error;
+ }
/* Update the length word. */
msg->bufferOffset += xdr_getpos (&xdr);
len = msg->bufferOffset;
- if (xdr_setpos (&xdr, 0) == 0)
+ if (xdr_setpos (&xdr, 0) == 0) {
+ remoteDispatchFormatError(&rerr, "%s", _("failed to change XDR
reply offset"));
goto xdr_error;
+ }
- if (!xdr_u_int (&xdr, &len))
+ if (!xdr_u_int (&xdr, &len)) {
+ remoteDispatchFormatError(&rerr, "%s", _("failed to update
reply length header"));
goto xdr_error;
+ }
xdr_destroy (&xdr);
xdr_free (data->ret_filter, (char*)&ret);
@@ -588,25 +597,27 @@ remoteDispatchClientCall (struct qemud_server *server,
return 0;
+xdr_error:
+ /* Bad stuff serializing reply. Try to send a little info
+ * back to client to assist in bug reporting/diagnosis */
+ xdr_free (data->ret_filter, (char*)&ret);
+ xdr_destroy (&xdr);
+ /* fallthrough */
+
+xdr_hdr_error:
+ VIR_WARN("Failed to serialize reply for program '%d' proc '%d'
as XDR",
+ msg->hdr.prog, msg->hdr.proc);
+ /* fallthrough */
+
rpc_error:
- /* Semi-bad stuff happened, we can still try to send back
- * an RPC error message to client */
+ /* Bad stuff (de-)serializing message, but we have an
+ * RPC error message we can send back to the client */
rv = remoteSerializeReplyError(client, &rerr, &msg->hdr);
if (rv >= 0)
VIR_FREE(msg);
return rv;
-
-xdr_error:
- /* Seriously bad stuff happened, so we'll kill off this client
- and not send back any RPC error */
- xdr_free (data->ret_filter, (char*)&ret);
- xdr_destroy (&xdr);
-fatal_error:
- VIR_WARN("Failed to serialize reply for program '%d' proc '%d'
as XDR",
- msg->hdr.prog, msg->hdr.proc);
- return -1;
}
--
1.7.1