Hi all-
I've been stuck on updating the rpc_init() function in support/nfs/
rpcmisc.c to use TI-RPC functions for a while now. This week I found
yet another issue, and would like to ask your opinion about how to
architect a solution.
rpc_init() is used only by rpc.statd and rpc.mountd, to set up their
RPC listeners. It has logic in it to detect the case where fd 0 is a
socket being passed in from inetd (I think that's what this does).
It also has some statics to save the UDP and TCP listener xprt's from
a previous call, so it doesn't create these again. Specifically for
rpc.statd, rpc_init() is called only once to set up the UDP and TCP
listeners, so I don't think those statics would ever be referenced
after being set during the first call.
Does rpc_init() really need to save the xprts for rpc.statd?
rpc_init() peeks at xp_port in the returned SVC_XPRT to decide whether
to use the saved xprt, but TI-RPC's service creation API doesn't fill
this field in. So this logic won't even work for xprts created with
TI-RPC calls. I seem to recall seeing some code in libtirpc that
already checks a list of xprts to prevent the creation of duplicates.
I also notice that rpc_init() uses xlog() to report errors, whereas
rpc.statd uses note(), and does not initialize the xlog() reporting
framework. So rpc.statd problems in this area are sporadically
reported, often without any identifying program name.
And, for rpc.statd, do the listener sockets need to be non-blocking?
There are four paths in rpc_init() that create listener sockets: one
is by passing RPC_ANYSOCK to the RPC library; one is using the pre-
existing fd 0 if it's a socket. The other two are local
implementations that create a fresh socket, but one sets O_NONBLOCK,
and the other doesn't. As far as I can tell, O_NONBLOCK support was
added just for rpc.mountd, but three of these four paths probably do
not create non-blocking listener sockets. What does rpc.statd need?
I'm considering creating a version of rpc_init() under utils/statd
that strips out all of the unnecessary features, uses note() instead
of xlot(), and then adds support for AF_INET6.
Does this make sense, or am I missing something?
--
Chuck Lever
chuck[dot]lever[at]oracle[dot]com
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