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1 /*
2 * Copyright (c) 2003 Apple Computer, Inc. All Rights Reserved.
3 *
4 * The contents of this file constitute Original Code as defined in and are
5 * subject to the Apple Public Source License Version 1.2 (the 'License').
6 * You may not use this file except in compliance with the License. Please obtain
7 * a copy of the License at http://www.apple.com/publicsource and read it before
8 * using this file.
9 *
10 * This Original Code and all software distributed under the License are
11 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS
12 * OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, INCLUDING WITHOUT
13 * LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
14 * PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. Please see the License for the
15 * specific language governing rights and limitations under the License.
16 */
17
18
19 //
20 // transwalkers - server side transition data walking support
21 //
22 // These are data walker operators for securely marshaling and unmarshaling
23 // data structures across IPC. They are also in charge of fixing byte order
24 // inconsistencies between server and clients.
25 //
26 #include <transwalkers.h>
27
28
29 using LowLevelMemoryUtilities::increment;
30 using LowLevelMemoryUtilities::difference;
31
32
33 bool flipClient()
34 {
35 return Server::connection().process.byteFlipped();
36 }
37
38
39 //
40 // CheckingRelocateWalkers
41 //
42 CheckingReconstituteWalker::CheckingReconstituteWalker(void *ptr, void *base, size_t size, bool flip)
43 : mBase(base), mFlip(flip)
44 {
45 if (mFlip)
46 Flippers::flip(mBase); // came in reversed; fix for base use
47 mOffset = difference(ptr, mBase);
48 mLimit = increment(mBase, size);
49 }
50
51
52 //
53 // Relocation support
54 //
55 void relocate(Context &context, void *base, Context::Attr *attrs, uint32 attrSize)
56 {
57 flip(context);
58 CheckingReconstituteWalker relocator(attrs, base, attrSize, flipClient());
59 context.ContextAttributes = attrs; // fix context->attr vector link
60 for (uint32 n = 0; n < context.attributesInUse(); n++)
61 walk(relocator, context[n]);
62 }
63
64
65 //
66 // Outbound flipping support
67 //
68 FlipWalker::~FlipWalker()
69 {
70 for (set<Flipper>::const_iterator it = mFlips.begin(); it != mFlips.end(); it++)
71 delete it->impl;
72 }
73
74 void FlipWalker::doFlips(bool active)
75 {
76 if (active) {
77 secdebug("flipwalkers", "starting outbound flips");
78 for (set<Flipper>::const_iterator it = mFlips.begin(); it != mFlips.end(); it++)
79 it->impl->flip();
80 secdebug("flipwalkers", "outbound flips done");
81 }
82 }