toolkit/profile/ProfileUnlockerWin.cpp

   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 http://mozilla.org/MPL/2.0/. */
   6
   7 #include "ProfileUnlockerWin.h"
   8 #include "nsCOMPtr.h"
   9 #include "nsIFile.h"
  10 #include "nsTArray.h"
  11 #include "nsXPCOM.h"
  12
  13 namespace mozilla {
  14
  15 /**
  16  * RAII class to obtain and manage a handle to a Restart Manager session.
  17  * It opens a new handle upon construction and releases it upon destruction.
  18  */
  19 class MOZ_STACK_CLASS ScopedRestartManagerSession {
  20  public:
  21   explicit ScopedRestartManagerSession(ProfileUnlockerWin& aUnlocker)
  22       : mError(ERROR_INVALID_HANDLE),
  23         mHandle((DWORD)-1)  // 0 is a valid restart manager handle
  24         ,
  25         mUnlocker(aUnlocker) {
  26     mError = mUnlocker.StartSession(mHandle);
  27   }
  28
  29   ~ScopedRestartManagerSession() {
  30     if (mError == ERROR_SUCCESS) {
  31       mUnlocker.EndSession(mHandle);
  32     }
  33   }
  34
  35   /**
  36    * @return true if the handle is a valid Restart Ranager handle.
  37    */
  38   inline bool ok() { return mError == ERROR_SUCCESS; }
  39
  40   /**
  41    * @return the Restart Manager handle to pass to other Restart Manager APIs.
  42    */
  43   inline DWORD handle() { return mHandle; }
  44
  45  private:
  46   DWORD mError;
  47   DWORD mHandle;
  48   ProfileUnlockerWin& mUnlocker;
  49 };
  50
  51 ProfileUnlockerWin::ProfileUnlockerWin(const nsAString& aFileName)
  52     : mRmStartSession(nullptr),
  53       mRmRegisterResources(nullptr),
  54       mRmGetList(nullptr),
  55       mRmEndSession(nullptr),
  56       mFileName(aFileName) {}
  57
  58 ProfileUnlockerWin::~ProfileUnlockerWin() {}
  59
  60 NS_IMPL_ISUPPORTS(ProfileUnlockerWin, nsIProfileUnlocker)
  61
  62 nsresult ProfileUnlockerWin::Init() {
  63   MOZ_ASSERT(!mRestartMgrModule);
  64   if (mFileName.IsEmpty()) {
  65     return NS_ERROR_ILLEGAL_VALUE;
  66   }
  67
  68   nsModuleHandle module(::LoadLibraryW(L"Rstrtmgr.dll"));
  69   if (!module) {
  70     return NS_ERROR_NOT_AVAILABLE;
  71   }
  72   mRmStartSession = reinterpret_cast<RMSTARTSESSION>(
  73       ::GetProcAddress(module, "RmStartSession"));
  74   if (!mRmStartSession) {
  75     return NS_ERROR_UNEXPECTED;
  76   }
  77   mRmRegisterResources = reinterpret_cast<RMREGISTERRESOURCES>(
  78       ::GetProcAddress(module, "RmRegisterResources"));
  79   if (!mRmRegisterResources) {
  80     return NS_ERROR_UNEXPECTED;
  81   }
  82   mRmGetList =
  83       reinterpret_cast<RMGETLIST>(::GetProcAddress(module, "RmGetList"));
  84   if (!mRmGetList) {
  85     return NS_ERROR_UNEXPECTED;
  86   }
  87   mRmEndSession =
  88       reinterpret_cast<RMENDSESSION>(::GetProcAddress(module, "RmEndSession"));
  89   if (!mRmEndSession) {
  90     return NS_ERROR_UNEXPECTED;
  91   }
  92
  93   mRestartMgrModule.steal(module);
  94   return NS_OK;
  95 }
  96
  97 DWORD
  98 ProfileUnlockerWin::StartSession(DWORD& aHandle) {
  99   WCHAR sessionKey[CCH_RM_SESSION_KEY + 1] = {0};
 100   return mRmStartSession(&aHandle, 0, sessionKey);
 101 }
 102
 103 void ProfileUnlockerWin::EndSession(DWORD aHandle) { mRmEndSession(aHandle); }
 104
 105 NS_IMETHODIMP
 106 ProfileUnlockerWin::Unlock(uint32_t aSeverity) {
 107   if (!mRestartMgrModule) {
 108     return NS_ERROR_NOT_INITIALIZED;
 109   }
 110
 111   if (aSeverity != FORCE_QUIT) {
 112     return NS_ERROR_NOT_IMPLEMENTED;
 113   }
 114
 115   ScopedRestartManagerSession session(*this);
 116   if (!session.ok()) {
 117     return NS_ERROR_FAILURE;
 118   }
 119
 120   LPCWSTR resources[] = {mFileName.get()};
 121   DWORD error = mRmRegisterResources(session.handle(), 1, resources, 0, nullptr,
 122                                      0, nullptr);
 123   if (error != ERROR_SUCCESS) {
 124     return NS_ERROR_FAILURE;
 125   }
 126
 127   // Using a AutoTArray here because we expect the required size to be 1.
 128   AutoTArray<RM_PROCESS_INFO, 1> info;
 129   UINT numEntries;
 130   UINT numEntriesNeeded = 1;
 131   error = ERROR_MORE_DATA;
 132   DWORD reason = RmRebootReasonNone;
 133   while (error == ERROR_MORE_DATA) {
 134     info.SetLength(numEntriesNeeded);
 135     numEntries = numEntriesNeeded;
 136     error = mRmGetList(session.handle(), &numEntriesNeeded, &numEntries,
 137                        &info[0], &reason);
 138   }
 139   if (error != ERROR_SUCCESS) {
 140     return NS_ERROR_FAILURE;
 141   }
 142   if (numEntries == 0) {
 143     // Nobody else is locking the file; the other process must have terminated
 144     return NS_OK;
 145   }
 146
 147   nsresult rv = NS_ERROR_FAILURE;
 148   for (UINT i = 0; i < numEntries; ++i) {
 149     rv = TryToTerminate(info[i].Process);
 150     if (NS_SUCCEEDED(rv)) {
 151       return NS_OK;
 152     }
 153   }
 154
 155   // If nothing could be unlocked then we return the error code of the last
 156   // failure that was returned.
 157   return rv;
 158 }
 159
 160 nsresult ProfileUnlockerWin::TryToTerminate(RM_UNIQUE_PROCESS& aProcess) {
 161   // Subtle: If the target process terminated before this call to OpenProcess,
 162   // this call will still succeed. This is because the restart manager session
 163   // internally retains a handle to the target process. The rules for Windows
 164   // PIDs state that the PID of a terminated process remains valid as long as
 165   // at least one handle to that process remains open, so when we reach this
 166   // point the PID is still valid and the process will open successfully.
 167   DWORD accessRights = PROCESS_QUERY_LIMITED_INFORMATION | PROCESS_TERMINATE;
 168   nsAutoHandle otherProcess(
 169       ::OpenProcess(accessRights, FALSE, aProcess.dwProcessId));
 170   if (!otherProcess) {
 171     return NS_ERROR_FAILURE;
 172   }
 173
 174   FILETIME creationTime, exitTime, kernelTime, userTime;
 175   if (!::GetProcessTimes(otherProcess, &creationTime, &exitTime, &kernelTime,
 176                          &userTime)) {
 177     return NS_ERROR_FAILURE;
 178   }
 179   if (::CompareFileTime(&aProcess.ProcessStartTime, &creationTime)) {
 180     return NS_ERROR_NOT_AVAILABLE;
 181   }
 182
 183   WCHAR imageName[MAX_PATH];
 184   DWORD imageNameLen = MAX_PATH;
 185   if (!::QueryFullProcessImageNameW(otherProcess, 0, imageName,
 186                                     &imageNameLen)) {
 187     // The error codes for this function are not very descriptive. There are
 188     // actually two failure cases here: Either the call failed because the
 189     // process is no longer running, or it failed for some other reason. We
 190     // need to know which case that is.
 191     DWORD otherProcessExitCode;
 192     if (!::GetExitCodeProcess(otherProcess, &otherProcessExitCode) ||
 193         otherProcessExitCode == STILL_ACTIVE) {
 194       // The other process is still running.
 195       return NS_ERROR_FAILURE;
 196     }
 197     // The other process must have terminated. We should return NS_OK so that
 198     // this process may proceed with startup.
 199     return NS_OK;
 200   }
 201   nsCOMPtr<nsIFile> otherProcessImageName;
 202   if (NS_FAILED(NS_NewLocalFile(nsDependentString(imageName, imageNameLen),
 203                                 getter_AddRefs(otherProcessImageName)))) {
 204     return NS_ERROR_FAILURE;
 205   }
 206   nsAutoString otherProcessLeafName;
 207   if (NS_FAILED(otherProcessImageName->GetLeafName(otherProcessLeafName))) {
 208     return NS_ERROR_FAILURE;
 209   }
 210
 211   imageNameLen = MAX_PATH;
 212   if (!::QueryFullProcessImageNameW(::GetCurrentProcess(), 0, imageName,
 213                                     &imageNameLen)) {
 214     return NS_ERROR_FAILURE;
 215   }
 216   nsCOMPtr<nsIFile> thisProcessImageName;
 217   if (NS_FAILED(NS_NewLocalFile(nsDependentString(imageName, imageNameLen),
 218                                 getter_AddRefs(thisProcessImageName)))) {
 219     return NS_ERROR_FAILURE;
 220   }
 221   nsAutoString thisProcessLeafName;
 222   if (NS_FAILED(thisProcessImageName->GetLeafName(thisProcessLeafName))) {
 223     return NS_ERROR_FAILURE;
 224   }
 225
 226   // Make sure the image leaf names match
 227   if (_wcsicmp(otherProcessLeafName.get(), thisProcessLeafName.get())) {
 228     return NS_ERROR_NOT_AVAILABLE;
 229   }
 230
 231   // We know that another process holds the lock and that it shares the same
 232   // image name as our process. Let's kill it.
 233   // Subtle: TerminateProcess returning ERROR_ACCESS_DENIED is actually an
 234   // indicator that the target process managed to shut down on its own. In that
 235   // case we should return NS_OK since we may proceed with startup.
 236   if (!::TerminateProcess(otherProcess, 1) &&
 237       ::GetLastError() != ERROR_ACCESS_DENIED) {
 238     return NS_ERROR_FAILURE;
 239   }
 240
 241   return NS_OK;
 242 }
 243
 244 }  // namespace mozilla