glibc/sunrpc/pmap_prot2.c
Andreas Jaeger 021db4be6f Make sunrpc code usable again
New configure option --enable-obsolete-rpc makes the deprecated RPC
  headers and functions available at compile time as they were before
  version 2.14.  This option will be removed at some time in the future
  after the TI-RPC library becomes fully sufficient for the needs of
  existing applications.
2012-05-10 20:19:53 +02:00

114 lines
4.0 KiB
C

/*
* pmap_prot2.c
* Protocol for the local binder service, or pmap.
*
* Copyright (c) 2010, Oracle America, Inc.
*
* 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 the "Oracle America, 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.
*/
#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 = (xdrs->x_op == XDR_FREE);
struct pmaplist *next = NULL;
while (TRUE)
{
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);
}
}
libc_hidden_nolink_sunrpc (xdr_pmaplist, GLIBC_2_0)