On Thu, Jun 23, 2011 at 04:19:37PM -0600, Eric Blake wrote:
> On 06/22/2011 09:33 AM, Daniel P. Berrange wrote:
> > This provides a new struct that contains a buffer for the RPC
> > message header+payload, as well as a decoded copy of the message
> > header. There is an API for applying a XDR encoding & decoding
> > of the message headers and payloads. There are also APIs for
> > maintaining a simple FIFO queue of message instances.
> >
> > Expected usage scenarios are:
> >
> > To send a message
> >
> > msg = virNetMessageNew()
> >
> > ...fill in msg->header fields..
> > virNetMessageEncodeHeader(msg)
> > ...loook at msg->header fields to determine payload filter
> > virNetMessageEncodePayload(msg, xdrfilter, data)
> > ...send msg->bufferLength worth of data from buffer
> >
> > To receive a message
> >
> > msg = virNetMessageNew()
> > ...read VIR_NET_MESSAGE_LEN_MAX of data into buffer
> > virNetMessageDecodeLength(msg)
> > ...read msg->bufferLength-msg->bufferOffset of data into buffer
> > virNetMessageDecodeHeader(msg)
> > ...look at msg->header fields to determine payload filter
> > virNetMessageDecodePayload(msg, xdrfilter, data)
> > ...run payload processor
>
> 'make check' fails:
>
> virnetmessagetest-virnetmessagetest.o: In function
> `testMessageHeaderEncode':
> /home/remote/eblake/libvirt/tests/virnetmessagetest.c:57: undefined
> reference to `virNetMessageEncodeHeader'
>
> But that was easy enough to fix.
Sigh. I have rebased this patch series sooooo many times
now, that I lost some pieces :-( Your suggested change
is what I originally had.
> > +++ b/src/rpc/virnetmessage.h
> > @@ -0,0 +1,82 @@
> > +/*
>
> > +
> > +#ifndef __VIR_NET_MESSAGE_H__
> > +# define __VIR_NET_MESSAGE_H__
> > +
> > +# include <stdbool.h>
>
> Is this include still necessary?
No, it should be able to go.
>
> > +int virtTestDifferenceBin(FILE *stream,
> > + const char *expect,
> > + const char *actual,
> > + size_t length)
> > +{
> > + size_t start = 0, end = length;
> > + ssize_t i;
> > +
> > + if (!virTestGetDebug())
> > + return 0;
> > +
> > + if (virTestGetDebug() < 2) {
> > + /* Skip to first character where they differ */
> > + for (i = 0 ; i < length ; i++) {
> > + if (expect[i] != actual[i]) {
> > + start = i;
> > + break;
> > + }
> > + }
> > +
> > + /* Work backwards to last character where they differ */
> > + for (i = (length -1) ; i >= 0 ; i--) {
> > + if (expect[i] != actual[i]) {
> > + end = i;
> > + break;
> > + }
> > + }
> > + }
> > + /* Round to nearest boundary of 4 */
> > + start -= (start % 4);
> > + end += 4 - (end % 4);
>
> This could make end go beyond length, if the difference was in the last
> byte or two on an unaligned length. And if expect or actual are also
> unaligned, then this means that reading beyond bounds could segfault (at
> any rate, valgrind will certainly call you on it).
Hmm, interesting edge case.
Daniel
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