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+/*
+ * Copyright (c) 2009, Sun Microsystems, Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ * - Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ * - Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ * - Neither the name of Sun Microsystems, Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/*
+ * pmap_prot2.c
+ * Protocol for the local binder service, or pmap.
+ *
+ * Copyright (C) 1984, Sun Microsystems, Inc.
+ */
+
+#include <assert.h>
+
+#include <rpc/types.h>
+#include <rpc/xdr.h>
+#include <rpc/pmap_prot.h>
+
+
+/*
+ * What is going on with linked lists? (!)
+ * First recall the link list declaration from pmap_prot.h:
+ *
+ * struct pmaplist {
+ * struct pmap pml_map;
+ * 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) {
+ *
+ * case TRUE: struct {
+ * struct pmap;
+ * pmaplist_t foo;
+ * };
+ *
+ * case FALSE: struct {};
+ * } pmaplist_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
+ * xdr union, pamplist_t.
+ *
+ * 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!
+ */
+bool_t
+xdr_pmaplist(xdrs, rp)
+ XDR *xdrs;
+ 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.
+ */
+ bool_t more_elements;
+ int freeing;
+ struct pmaplist **next = NULL; /* pacify gcc */
+
+ assert(xdrs != NULL);
+ assert(rp != NULL);
+
+ freeing = (xdrs->x_op == XDR_FREE);
+
+ for (;;) {
+ more_elements = (bool_t)(*rp != NULL);
+ if (! xdr_bool(xdrs, &more_elements))
+ return (FALSE);
+ if (! 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 ...
+ */
+ if (freeing)
+ next = &((*rp)->pml_next);
+ if (! xdr_reference(xdrs, (caddr_t *)rp,
+ (u_int)sizeof(struct pmaplist), (xdrproc_t)xdr_pmap))
+ return (FALSE);
+ rp = (freeing) ? next : &((*rp)->pml_next);
+ }
+}
+
+
+/*
+ * xdr_pmaplist_ptr() is specified to take a PMAPLIST *, but is identical in
+ * functionality to xdr_pmaplist().
+ */
+bool_t
+xdr_pmaplist_ptr(xdrs, rp)
+ XDR *xdrs;
+ struct pmaplist *rp;
+{
+ return xdr_pmaplist(xdrs, (struct pmaplist **)(void *)rp);
+}