chrome/browser/install_verification/win/loaded_modules_snapshot.cc

   1 // Copyright 2013 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 "chrome/browser/install_verification/win/loaded_modules_snapshot.h"
   6
   7 #include <Psapi.h>
   8
   9 #include "base/logging.h"
  10
  11 bool GetLoadedModulesSnapshot(std::vector<HMODULE>* snapshot) {
  12   DCHECK(snapshot);
  13   DCHECK_EQ(0u, snapshot->size());
  14   snapshot->resize(1);
  15
  16   HANDLE process = ::GetCurrentProcess();
  17
  18   // We will retry at least once after first determining |bytes_required|. If
  19   // the list of modules changes after we receive |bytes_required| we may retry
  20   // more than once.
  21   int retries_remaining = 5;
  22   do {
  23     DWORD bytes_required = 0;
  24     // EnumProcessModules returns 'success' even if the buffer size is too
  25     // small.
  26     if (!::EnumProcessModules(process,
  27                               &(*snapshot)[0],
  28                               snapshot->size() * sizeof(HMODULE),
  29                               &bytes_required)) {
  30       DPLOG(ERROR) << "::EnumProcessModules failed.";
  31       return false;
  32     }
  33     DCHECK_EQ(0u, bytes_required % sizeof(HMODULE));
  34     size_t num_modules = bytes_required / sizeof(HMODULE);
  35     if (num_modules <= snapshot->size()) {
  36       // Buffer size was too big, presumably because a module was unloaded.
  37       snapshot->erase(snapshot->begin() + num_modules, snapshot->end());
  38       return true;
  39     } else if (num_modules == 0) {
  40       DLOG(ERROR) << "Can't determine the module list size.";
  41       return false;
  42     } else {
  43       // Buffer size was too small. Try again with a larger buffer.
  44       snapshot->resize(num_modules, NULL);
  45     }
  46   } while (--retries_remaining);
  47
  48   DLOG(ERROR) << "Failed to enumerate modules.";
  49   return false;
  50 }