Re: [libvirt] [PATCH 01/15] Defines the basics of a generic RPC protocol in XDR
On 12/16/2010 04:21 AM, Daniel P. Berrange wrote:
This patch defines the basics of a generic RPC protocol in XDR.
This is wire ABI compatible with the original remote_protocol.x.
diff --git a/.x-sc_preprocessor_indentation b/.x-sc_preprocessor_indentation
new file mode 100644
index 0000000..30273f8
--- /dev/null
+++ b/.x-sc_preprocessor_indentation
@@ -0,0 +1 @@
+src/rpc/virnetprotocol.h
\ No newline at end of file
This file should have had a newline, if it is even needed. However, I
think that you are better off changing preprocessor_exempt in cfg.mk
instead of adding this file.
diff --git a/Makefile.am b/Makefile.am
index c525e65..a400f59 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -21,6 +21,7 @@ syntax_check_exceptions = \
.x-sc_bindtextdomain \
.x-sc_m4_quote_check \
.x-sc_po_check \
+ .x-sc_preprocessor_indentation \
Which means you also don't need this change.
diff --git a/src/rpc/virnetprotocol.x b/src/rpc/virnetprotocol.x
new file mode 100644
index 0000000..10ece6f
--- /dev/null
+++ b/src/rpc/virnetprotocol.x
+
+/*----- Data types. -----*/
+
+/* Maximum total message size (serialised). */
+const VIR_NET_MESSAGE_MAX = 262144;
+
+/* Size of struct virNetMessageHeader (serialized)*/
Love the comment copy-and-paste inconsistency from remote_protocol.x
(-sed vs. -zed).
+const VIR_NET_MESSAGE_HEADER_MAX = 24;
+
+/* Size of message payload */
+const VIR_NET_MESSAGE_PAYLOAD_MAX = 262120;
Would it be better to write VIR_NET_MESSAGE_PAYLOAD_MAX =
VIR_NET_MESSAGE_MAX - VIR_NET_MESSAGE_HEADER_MAX? But that's just cosmetic.
+
+/* Size of message length field. Not counted in VIR_NET_MESSAGE_MAX */
+const VIR_NET_MESSAGE_LEN_MAX = 4;
+
+const VIR_NET_MESSAGE_STRING_MAX = 65536;
You lost a useful comment from remote_protocol.h:
/* Length of long, but not unbounded, strings.
* This is an arbitrary limit designed to stop the decoder from trying
* to allocate unbounded amounts of memory when fed with a bad message.
*/
+ * and the 'status' field varies according to:
+ *
+ * - type == VIR_NET_CALL
+ * * VIR_NET_OK always
+ *
+ * - type == VIR_NET_REPLY
+ * * VIR_NET_OK if RPC finished successfully
+ * * VIR_NET_ERROR if something failed
+ *
+ * - type == VIR_NET_MESSAGE
+ * * VIR_NET_OK always
+ *
+ * - type == VIR_NET_STREAM
+ * * VIR_NET_CONTINUE if more data is following
+ * * VIR_NET_OK if stream is complete
+ * * VIR_NET_ERROR if stream had an error
+ *
+ * Payload varies according to type and status:
+ *
+ * - type == VIR_NET_CALL
+ * XXX_args for procedure
+ *
+ * - type == VIR_NET_REPLY
+ * * status == VIR_NET_OK
+ * XXX_ret for procedure
+ * * status == VIR_NET_ERROR
+ * remote_error Error information
+ *
+ * - type == VIR_NET_MESSAGE
+ * * status == VIR_NET_OK
+ * XXX_args for procedure
+ * * status == VIR_NET_ERROR
+ * remote_error Error information
This is pure copy-and-paste from remote_protocol.x, but it doesnt' make
sense to me. Earlier, you said that VIR_NET_MESSAGE implies status is
VIR_NET_OK always, and that messages are asynchronous, rather than in
reply to a message. Either this should be:
- type == VIR_NET_MESSAGE
XXX_msg according to proc
or you need to allow for VIR_NET_MESSAGE to pass status==VIR_NET_ERROR.
--
Eric Blake eblake(a)redhat.com +1-801-349-2682
Libvirt virtualization library http://libvirt.org
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