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28f540f4 RM |
1 | /* |
2 | * pmap_prot2.c | |
3 | * Protocol for the local binder service, or pmap. | |
4 | * | |
a7ab6ec8 UD |
5 | * Copyright (c) 2010, Oracle America, Inc. |
6 | * | |
7 | * Redistribution and use in source and binary forms, with or without | |
8 | * modification, are permitted provided that the following conditions are | |
9 | * met: | |
10 | * | |
11 | * * Redistributions of source code must retain the above copyright | |
12 | * notice, this list of conditions and the following disclaimer. | |
13 | * * Redistributions in binary form must reproduce the above | |
14 | * copyright notice, this list of conditions and the following | |
15 | * disclaimer in the documentation and/or other materials | |
16 | * provided with the distribution. | |
17 | * * Neither the name of the "Oracle America, Inc." nor the names of its | |
18 | * contributors may be used to endorse or promote products derived | |
19 | * from this software without specific prior written permission. | |
20 | * | |
21 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS | |
22 | * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT | |
23 | * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS | |
24 | * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE | |
25 | * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, | |
26 | * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
27 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE | |
28 | * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS | |
29 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, | |
30 | * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING | |
31 | * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE | |
32 | * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
28f540f4 RM |
33 | */ |
34 | ||
35 | #include <rpc/types.h> | |
36 | #include <rpc/xdr.h> | |
37 | #include <rpc/pmap_prot.h> | |
82f43dd2 | 38 | #include <shlib-compat.h> |
28f540f4 RM |
39 | |
40 | ||
e7fd8a39 | 41 | /* |
28f540f4 RM |
42 | * What is going on with linked lists? (!) |
43 | * First recall the link list declaration from pmap_prot.h: | |
44 | * | |
45 | * struct pmaplist { | |
e7fd8a39 UD |
46 | * struct pmap pml_map; |
47 | * struct pmaplist *pml_map; | |
28f540f4 RM |
48 | * }; |
49 | * | |
e7fd8a39 | 50 | * Compare that declaration with a corresponding xdr declaration that |
28f540f4 RM |
51 | * is (a) pointer-less, and (b) recursive: |
52 | * | |
53 | * typedef union switch (bool_t) { | |
28f540f4 | 54 | * |
e7fd8a39 UD |
55 | * case TRUE: struct { |
56 | * struct pmap; | |
57 | * pmaplist_t foo; | |
58 | * }; | |
59 | * | |
60 | * case FALSE: struct {}; | |
28f540f4 RM |
61 | * } pmaplist_t; |
62 | * | |
63 | * Notice that the xdr declaration has no nxt pointer while | |
64 | * the C declaration has no bool_t variable. The bool_t can be | |
65 | * interpreted as ``more data follows me''; if FALSE then nothing | |
66 | * follows this bool_t; if TRUE then the bool_t is followed by | |
e7fd8a39 UD |
67 | * an actual struct pmap, and then (recursively) by the |
68 | * xdr union, pamplist_t. | |
28f540f4 RM |
69 | * |
70 | * This could be implemented via the xdr_union primitive, though this | |
71 | * would cause a one recursive call per element in the list. Rather than do | |
72 | * that we can ``unwind'' the recursion | |
73 | * into a while loop and do the union arms in-place. | |
74 | * | |
75 | * The head of the list is what the C programmer wishes to past around | |
76 | * the net, yet is the data that the pointer points to which is interesting; | |
77 | * this sounds like a job for xdr_reference! | |
78 | */ | |
79 | bool_t | |
9d46370c | 80 | xdr_pmaplist (XDR *xdrs, struct pmaplist **rp) |
28f540f4 | 81 | { |
e7fd8a39 UD |
82 | /* |
83 | * more_elements is pre-computed in case the direction is | |
84 | * XDR_ENCODE or XDR_FREE. more_elements is overwritten by | |
85 | * xdr_bool when the direction is XDR_DECODE. | |
86 | */ | |
87 | bool_t more_elements; | |
88 | int freeing = (xdrs->x_op == XDR_FREE); | |
72e61500 | 89 | struct pmaplist *next = NULL; |
28f540f4 | 90 | |
e7fd8a39 UD |
91 | while (TRUE) |
92 | { | |
93 | more_elements = (bool_t) (*rp != NULL); | |
7b57bfe5 | 94 | if (!xdr_bool (xdrs, &more_elements)) |
e7fd8a39 UD |
95 | return FALSE; |
96 | if (!more_elements) | |
97 | return TRUE; /* we are done */ | |
98 | /* | |
99 | * the unfortunate side effect of non-recursion is that in | |
100 | * the case of freeing we must remember the next object | |
101 | * before we free the current object ... | |
102 | */ | |
103 | if (freeing) | |
72e61500 | 104 | next = (*rp)->pml_next; |
7b57bfe5 UD |
105 | if (!xdr_reference (xdrs, (caddr_t *) rp, |
106 | (u_int) sizeof (struct pmaplist), | |
107 | (xdrproc_t) xdr_pmap)) | |
e7fd8a39 | 108 | return FALSE; |
72e61500 | 109 | rp = freeing ? &next : &((*rp)->pml_next); |
e7fd8a39 | 110 | } |
28f540f4 | 111 | } |
021db4be | 112 | libc_hidden_nolink_sunrpc (xdr_pmaplist, GLIBC_2_0) |