sandbox/win/src/shared_handles.cc

   1 // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "sandbox/win/src/shared_handles.h"
   6
   7 namespace sandbox {
   8
   9 // Note once again the the assumption here is that the shared memory is
  10 // initialized with zeros in the process that calls SetHandle and that
  11 // the process that calls GetHandle 'sees' this memory.
  12
  13 SharedHandles::SharedHandles() {
  14   shared_.items = NULL;
  15   shared_.max_items = 0;
  16 }
  17
  18 bool SharedHandles::Init(void* raw_mem, size_t size_bytes) {
  19   if (size_bytes < sizeof(shared_.items[0])) {
  20     // The shared memory is too small!
  21     return false;
  22   }
  23   shared_.items = static_cast<SharedItem*>(raw_mem);
  24   shared_.max_items = size_bytes / sizeof(shared_.items[0]);
  25   return true;
  26 }
  27
  28 // Note that an empty slot is marked with a tag == 0 that is why is
  29 // not a valid imput tag
  30 bool SharedHandles::SetHandle(uint32 tag, HANDLE handle) {
  31   if (0 == tag) {
  32     // Invalid tag
  33     return false;
  34   }
  35   // Find empty slot and put the tag and the handle there
  36   SharedItem* empty_slot = FindByTag(0);
  37   if (NULL == empty_slot) {
  38     return false;
  39   }
  40   empty_slot->tag = tag;
  41   empty_slot->item = handle;
  42   return true;
  43 }
  44
  45 bool SharedHandles::GetHandle(uint32 tag, HANDLE* handle) {
  46   if (0 == tag) {
  47     // Invalid tag
  48     return false;
  49   }
  50   SharedItem* found = FindByTag(tag);
  51   if (NULL == found) {
  52     return false;
  53   }
  54   *handle = found->item;
  55   return true;
  56 }
  57
  58 SharedHandles::SharedItem* SharedHandles::FindByTag(uint32 tag) {
  59   for (size_t ix = 0; ix != shared_.max_items; ++ix) {
  60     if (tag == shared_.items[ix].tag) {
  61       return &shared_.items[ix];
  62     }
  63   }
  64   return NULL;
  65 }
  66
  67 }  // namespace sandbox