toolkit/xre/SafeMode.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef mozilla_SafeMode_h
   8 #define mozilla_SafeMode_h
   9
  10 // NB: This code must be able to run apart from XPCOM
  11
  12 #include "mozilla/CmdLineAndEnvUtils.h"
  13 #include "mozilla/Maybe.h"
  14
  15 #if defined(XP_WIN)
  16 #  include "mozilla/PolicyChecks.h"
  17 #  include <windows.h>
  18 #endif  // defined(XP_WIN)
  19
  20 // Undo X11/X.h's definition of None
  21 #undef None
  22
  23 namespace mozilla {
  24
  25 enum class SafeModeFlag : uint32_t {
  26   None = 0,
  27   Unset = (1 << 0),
  28   NoKeyPressCheck = (1 << 1),
  29 };
  30
  31 MOZ_MAKE_ENUM_CLASS_BITWISE_OPERATORS(SafeModeFlag)
  32
  33 template <typename CharT>
  34 inline Maybe<bool> IsSafeModeRequested(
  35     int& aArgc, CharT* aArgv[],
  36     const SafeModeFlag aFlags = SafeModeFlag::Unset) {
  37   CheckArgFlag checkArgFlags = CheckArgFlag::None;
  38   if (aFlags & SafeModeFlag::Unset) {
  39     checkArgFlags |= CheckArgFlag::RemoveArg;
  40   }
  41
  42   ArgResult ar = CheckArg(aArgc, aArgv, "safe-mode", nullptr, checkArgFlags);
  43   if (ar == ARG_BAD) {
  44     return Nothing();
  45   }
  46
  47   bool result = ar == ARG_FOUND;
  48
  49 #if defined(XP_WIN)
  50   // If the shift key is pressed and the ctrl and / or alt keys are not pressed
  51   // during startup, start in safe mode. GetKeyState returns a short and the
  52   // high order bit will be 1 if the key is pressed. By masking the returned
  53   // short with 0x8000 the result will be 0 if the key is not pressed and
  54   // non-zero otherwise.
  55   if (!(aFlags & SafeModeFlag::NoKeyPressCheck) &&
  56       (GetKeyState(VK_SHIFT) & 0x8000) && !(GetKeyState(VK_CONTROL) & 0x8000) &&
  57       !(GetKeyState(VK_MENU) & 0x8000) &&
  58       !EnvHasValue("MOZ_DISABLE_SAFE_MODE_KEY")) {
  59     result = true;
  60   }
  61
  62   if (result && PolicyCheckBoolean(L"DisableSafeMode")) {
  63     result = false;
  64   }
  65 #endif  // defined(XP_WIN)
  66
  67 #if defined(XP_MACOSX)
  68   if (!(aFlags & SafeModeFlag::NoKeyPressCheck) &&
  69       (GetCurrentEventKeyModifiers() & optionKey) &&
  70       !EnvHasValue("MOZ_DISABLE_SAFE_MODE_KEY")) {
  71     result = true;
  72   }
  73 #endif  // defined(XP_MACOSX)
  74
  75   // The Safe Mode Policy should not be enforced for the env var case
  76   // (used by updater and crash-recovery).
  77   if (EnvHasValue("MOZ_SAFE_MODE_RESTART")) {
  78     result = true;
  79     if (aFlags & SafeModeFlag::Unset) {
  80       // unset the env variable
  81       SaveToEnv("MOZ_SAFE_MODE_RESTART=");
  82     }
  83   }
  84
  85   return Some(result);
  86 }
  87
  88 }  // namespace mozilla
  89
  90 #endif  // mozilla_SafeMode_h