/* @(#)pmap_prot2.c 2.1 88/07/29 4.0 RPCSRC */
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#if !defined(lint) && defined(SCCSIDS)
static char sccsid
[] = "@(#)pmap_prot2.c 1.3 87/08/11 Copyr 1984 Sun Micro";
* Protocol for the local binder service, or pmap.
* Copyright (C) 1984, Sun Microsystems, Inc.
#include <rpc/pmap_prot.h>
* What is going on with linked lists? (!)
* First recall the link list declaration from pmap_prot.h:
* struct pmaplist *pml_map;
* Compare that declaration with a corresponding xdr declaration that
* is (a) pointer-less, and (b) recursive:
* typedef union switch (bool_t) {
* Notice that the xdr declaration has no nxt pointer while
* the C declaration has no bool_t variable. The bool_t can be
* interpreted as ``more data follows me''; if FALSE then nothing
* follows this bool_t; if TRUE then the bool_t is followed by
* an actual struct pmap, and then (recursively) by the
* This could be implemented via the xdr_union primitive, though this
* would cause a one recursive call per element in the list. Rather than do
* that we can ``unwind'' the recursion
* into a while loop and do the union arms in-place.
* The head of the list is what the C programmer wishes to past around
* the net, yet is the data that the pointer points to which is interesting;
* this sounds like a job for xdr_reference!
register struct pmaplist
**rp
;
* more_elements is pre-computed in case the direction is
* XDR_ENCODE or XDR_FREE. more_elements is overwritten by
* xdr_bool when the direction is XDR_DECODE.
register int freeing
= (xdrs
->x_op
== XDR_FREE
);
register struct pmaplist
**next
;
more_elements
= (bool_t
)(*rp
!= NULL
);
if (! xdr_bool(xdrs
, &more_elements
))
return (TRUE
); /* we are done */
* the unfortunate side effect of non-recursion is that in
* the case of freeing we must remember the next object
* before we free the current object ...
next
= &((*rp
)->pml_next
);
if (! xdr_reference(xdrs
, (caddr_t
*)rp
,
(u_int
)sizeof(struct pmaplist
), xdr_pmap
))
rp
= (freeing
) ? next
: &((*rp
)->pml_next
);