SecurityServer/transwalkers.cpp

   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 }