/* * Copyright (c) 1999 Apple Computer, Inc. All rights reserved. * * @APPLE_LICENSE_HEADER_START@ * * Portions Copyright (c) 1999 Apple Computer, Inc. All Rights * Reserved. This file contains Original Code and/or Modifications of * Original Code as defined in and that are subject to the Apple Public * Source License Version 1.1 (the "License"). You may not use this file * except in compliance with the License. Please obtain a copy of the * License at http://www.apple.com/publicsource and read it before using * this file. * * The Original Code and all software distributed under the License are * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE OR NON- INFRINGEMENT. Please see the * License for the specific language governing rights and limitations * under the License. * * @APPLE_LICENSE_HEADER_END@ */ /* * Sun RPC is a product of Sun Microsystems, Inc. and is provided for * unrestricted use provided that this legend is included on all tape * media and as a part of the software program in whole or part. Users * may copy or modify Sun RPC without charge, but are not authorized * to license or distribute it to anyone else except as part of a product or * program developed by the user. * * SUN RPC IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING THE * WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR * PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE. * * Sun RPC is provided with no support and without any obligation on the * part of Sun Microsystems, Inc. to assist in its use, correction, * modification or enhancement. * * SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE * INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY SUN RPC * OR ANY PART THEREOF. * * In no event will Sun Microsystems, Inc. be liable for any lost revenue * or profits or other special, indirect and consequential damages, even if * Sun has been advised of the possibility of such damages. * * Sun Microsystems, Inc. * 2550 Garcia Avenue * Mountain View, California 94043 */ #if defined(LIBC_SCCS) && !defined(lint) /*static char *sccsid = "from: @(#)pmap_prot2.c 1.3 87/08/11 Copyr 1984 Sun Micro";*/ /*static char *sccsid = "from: @(#)pmap_prot2.c 2.1 88/07/29 4.0 RPCSRC";*/ static char *rcsid = "$Id: pmap_prot2.c,v 1.2 1999/10/14 21:56:53 wsanchez Exp $"; #endif /* * pmap_prot2.c * Protocol for the local binder service, or pmap. * * Copyright (C) 1984, Sun Microsystems, Inc. */ #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) register XDR *xdrs; 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. */ bool_t more_elements; register int freeing = (xdrs->x_op == XDR_FREE); register struct pmaplist **next; 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), xdr_pmap)) return (FALSE); rp = (freeing) ? next : &((*rp)->pml_next); } }