On Fri, Dec 19, 2008 at 10:31:33AM -0500, Chuck Lever wrote:
> Preserve ABI compatibility between glibc's RPC implementation and
> the legacy RPC implementation in libtirpc by moving the rq_xprt
> field in the TI-RPC version of the svc_req struct so it is
> backwards compatible with the legacy version of this structure.
>
> Linux's legacy svc_req struct, from /usr/include/rpc/svc.h, looks
> like this:
>
> struct svc_req {
> rpcprog_t rq_prog; /* service program number */
> rpcvers_t rq_vers; /* service protocol version */
> rpcproc_t rq_proc; /* the desired procedure */
> struct opaque_auth rq_cred; /* raw creds from the wire */
> caddr_t rq_clntcred; /* read only cooked cred */
> SVCXPRT *rq_xprt; /* associated transport */
> };
>
> The new TI-RPC svc_req struct, from /usr/include/tirpc/rpc/svc.h,
> looks like this:
>
> struct svc_req {
> u_int32_t rq_prog; /* service program number */
> u_int32_t rq_vers; /* service protocol version */
> u_int32_t rq_proc; /* the desired procedure */
> struct opaque_auth rq_cred; /* raw creds from the wire */
> void *rq_clntcred; /* read only cooked cred */
> caddr_t rq_clntname; /* read only client name */
> caddr_t rq_svcname; /* read only cooked service cred */
> SVCXPRT *rq_xprt; /* associated transport */
> };
>
> Note the extra fields rq_clntname and rq_svcname. These are used for
> TI-RPC's RPCSEC GSS flavor support.
>
> This issue came to light because rpc.statd still uses only legacy RPC
> calls, and thus includes /usr/include/rpc/svc.h. However, other parts
> of nfs-utils now link with TI-RPC, so the legacy RPC functions in
> libtirpc are used in favor of glibc's RPC functions. The libtirpc svc
> functions use the new svc_req struct, but rpc.statd uses the old
> svc_req struct.
>
> Since the svc_req fields were different, rpc.statd broke after recent
> IPv6-related changes, even though I hadn't made any changes to it.
> Note that rpc.mountd also references the rq_xprt field, so it has the
> same issue.
>
> In most operating systems, there is only one rpc/svc.h and one version
> of svc_req so this is not a problem. We should audit all of the
> structures and functions under /usr/include/rpc and
> /usr/include/tirpc/rpc to ensure we have a reasonable level of
> backwards compatibility until such a time it is decided to merge these
> implementations or get rid of RPC support in glibc.
I think the glibc people don't want to update their RPC support--so it
should stay there as a legacy thing for backwards compatibility, but
eventually applications should be using something else.
As long as that "something else" supports both ipv6 and rpcsec_gss, I'm
happy....
--b.
>
> Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
> ---
>
> tirpc/rpc/svc.h | 5 ++++-
> 1 files changed, 4 insertions(+), 1 deletions(-)
>
> diff --git a/tirpc/rpc/svc.h b/tirpc/rpc/svc.h
> index ec5914f..ea2985d 100644
> --- a/tirpc/rpc/svc.h
> +++ b/tirpc/rpc/svc.h
> @@ -131,14 +131,17 @@ typedef struct __rpc_svcxprt {
> * Service request
> */
> struct svc_req {
> + /* ORDER: compatibility with legacy RPC */
> u_int32_t rq_prog; /* service program number */
> u_int32_t rq_vers; /* service protocol version */
> u_int32_t rq_proc; /* the desired procedure */
> struct opaque_auth rq_cred; /* raw creds from the wire */
> void *rq_clntcred; /* read only cooked cred */
> + SVCXPRT *rq_xprt; /* associated transport */
> +
> + /* New with TI-RPC */
> caddr_t rq_clntname; /* read only client name */
> caddr_t rq_svcname; /* read only cooked service cred */
> - SVCXPRT *rq_xprt; /* associated transport */
> };
>
> /*
>
> --
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