commit 2bb4c8d7ec8a98e1be9133d5901149a81ea9b5d9
Author: Chuck Lever <chuck.lever@oracle.com>
Date:   Wed Jan 28 09:19:07 2009 -0500

    backwards compatibility: fix order of fields in TI-RPC's svc_req
    
    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.
    
    Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
    Signed-off-by: Steve Dickson <steved@redhat.com>

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 */
 };
 
 /*