[20ec9e6] | 1 | /* |
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| 2 | * Sun RPC is a product of Sun Microsystems, Inc. and is provided for |
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| 3 | * unrestricted use provided that this legend is included on all tape |
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| 4 | * media and as a part of the software program in whole or part. Users |
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| 5 | * may copy or modify Sun RPC without charge, but are not authorized |
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| 6 | * to license or distribute it to anyone else except as part of a product or |
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| 7 | * program developed by the user. |
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| 8 | * |
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| 9 | * SUN RPC IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING THE |
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| 10 | * WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR |
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| 11 | * PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE. |
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| 12 | * |
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| 13 | * Sun RPC is provided with no support and without any obligation on the |
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| 14 | * part of Sun Microsystems, Inc. to assist in its use, correction, |
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| 15 | * modification or enhancement. |
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| 16 | * |
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| 17 | * SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE |
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| 18 | * INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY SUN RPC |
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| 19 | * OR ANY PART THEREOF. |
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| 20 | * |
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| 21 | * In no event will Sun Microsystems, Inc. be liable for any lost revenue |
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| 22 | * or profits or other special, indirect and consequential damages, even if |
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| 23 | * Sun has been advised of the possibility of such damages. |
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| 24 | * |
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| 25 | * Sun Microsystems, Inc. |
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| 26 | * 2550 Garcia Avenue |
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| 27 | * Mountain View, California 94043 |
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| 28 | */ |
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| 29 | |
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| 30 | #if defined(LIBC_SCCS) && !defined(lint) |
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| 31 | /*static char *sccsid = "from: @(#)pmap_prot2.c 1.3 87/08/11 Copyr 1984 Sun Micro";*/ |
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| 32 | /*static char *sccsid = "from: @(#)pmap_prot2.c 2.1 88/07/29 4.0 RPCSRC";*/ |
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| 33 | static char *rcsid = "$FreeBSD: src/lib/libc/rpc/pmap_prot2.c,v 1.7 1999/08/28 00:00:42 peter Exp $"; |
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| 34 | #endif |
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| 35 | |
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| 36 | /* |
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| 37 | * pmap_prot2.c |
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| 38 | * Protocol for the local binder service, or pmap. |
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| 39 | * |
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| 40 | * Copyright (C) 1984, Sun Microsystems, Inc. |
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| 41 | */ |
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| 42 | |
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| 43 | #ifdef HAVE_CONFIG_H |
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| 44 | #include "config.h" |
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| 45 | #endif |
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| 46 | |
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[cd450d2] | 47 | #ifndef __rtems__ |
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| 48 | /* XXX not needed in old.. */ |
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| 49 | #include <sys/types.h> |
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| 50 | #endif |
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[20ec9e6] | 51 | #include <rpc/types.h> |
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| 52 | #include <rpc/xdr.h> |
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| 53 | #include <rpc/pmap_prot.h> |
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| 54 | |
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| 55 | |
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| 56 | /* |
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| 57 | * What is going on with linked lists? (!) |
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| 58 | * First recall the link list declaration from pmap_prot.h: |
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| 59 | * |
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| 60 | * struct pmaplist { |
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| 61 | * struct pmap pml_map; |
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| 62 | * struct pmaplist *pml_map; |
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| 63 | * }; |
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| 64 | * |
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| 65 | * Compare that declaration with a corresponding xdr declaration that |
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| 66 | * is (a) pointer-less, and (b) recursive: |
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| 67 | * |
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| 68 | * typedef union switch (bool_t) { |
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| 69 | * |
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| 70 | * case TRUE: struct { |
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| 71 | * struct pmap; |
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| 72 | * pmaplist_t foo; |
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| 73 | * }; |
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| 74 | * |
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| 75 | * case FALSE: struct {}; |
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| 76 | * } pmaplist_t; |
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| 77 | * |
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| 78 | * Notice that the xdr declaration has no nxt pointer while |
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| 79 | * the C declaration has no bool_t variable. The bool_t can be |
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| 80 | * interpreted as ``more data follows me''; if FALSE then nothing |
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| 81 | * follows this bool_t; if TRUE then the bool_t is followed by |
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| 82 | * an actual struct pmap, and then (recursively) by the |
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| 83 | * xdr union, pamplist_t. |
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| 84 | * |
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| 85 | * This could be implemented via the xdr_union primitive, though this |
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| 86 | * would cause a one recursive call per element in the list. Rather than do |
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| 87 | * that we can ``unwind'' the recursion |
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| 88 | * into a while loop and do the union arms in-place. |
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| 89 | * |
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| 90 | * The head of the list is what the C programmer wishes to past around |
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| 91 | * the net, yet is the data that the pointer points to which is interesting; |
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| 92 | * this sounds like a job for xdr_reference! |
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| 93 | */ |
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| 94 | bool_t |
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| 95 | xdr_pmaplist( |
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| 96 | XDR *xdrs, |
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| 97 | struct pmaplist **rp) |
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| 98 | { |
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| 99 | /* |
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| 100 | * more_elements is pre-computed in case the direction is |
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| 101 | * XDR_ENCODE or XDR_FREE. more_elements is overwritten by |
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| 102 | * xdr_bool when the direction is XDR_DECODE. |
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| 103 | */ |
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| 104 | bool_t more_elements; |
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| 105 | register int freeing = (xdrs->x_op == XDR_FREE); |
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| 106 | register struct pmaplist **next = NULL; |
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| 107 | |
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| 108 | while (TRUE) { |
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| 109 | more_elements = (bool_t)(*rp != NULL); |
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| 110 | if (! xdr_bool(xdrs, &more_elements)) |
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| 111 | return (FALSE); |
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| 112 | if (! more_elements) |
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| 113 | return (TRUE); /* we are done */ |
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| 114 | /* |
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| 115 | * the unfortunate side effect of non-recursion is that in |
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| 116 | * the case of freeing we must remember the next object |
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| 117 | * before we free the current object ... |
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| 118 | */ |
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| 119 | if (freeing) |
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| 120 | next = &((*rp)->pml_next); |
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| 121 | if (! xdr_reference(xdrs, (caddr_t *)rp, |
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| 122 | (u_int)sizeof(struct pmaplist), (xdrproc_t) xdr_pmap)) |
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| 123 | return (FALSE); |
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| 124 | rp = (freeing) ? next : &((*rp)->pml_next); |
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| 125 | } |
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| 126 | } |
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