Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

16 files changed, 2628 insertions, 0 deletions

diff --git a/toolkit/components/maintenanceservice/Makefile.in b/toolkit/components/maintenanceservice/Makefile.in
new file mode 100644
index 0000000000..b07afbb0a9
--- /dev/null
+++ b/toolkit/components/maintenanceservice/Makefile.in
@@ -0,0 +1,13 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+ifndef MOZ_WINCONSOLE
+ifdef MOZ_DEBUG
+MOZ_WINCONSOLE = 1
+else
+MOZ_WINCONSOLE = 0
+endif
+endif
+
+include $(topsrcdir)/config/rules.mk
diff --git a/toolkit/components/maintenanceservice/bootstrapinstaller/maintenanceservice_installer.nsi b/toolkit/components/maintenanceservice/bootstrapinstaller/maintenanceservice_installer.nsi
new file mode 100644
index 0000000000..685458db0e
--- /dev/null
+++ b/toolkit/components/maintenanceservice/bootstrapinstaller/maintenanceservice_installer.nsi
@@ -0,0 +1,269 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+; Set verbosity to 3 (e.g. no script) to lessen the noise in the build logs
+!verbose 3
+
+; 7-Zip provides better compression than the lzma from NSIS so we add the files
+; uncompressed and use 7-Zip to create a SFX archive of it
+SetDatablockOptimize on
+SetCompress off
+CRCCheck on
+
+RequestExecutionLevel admin
+
+Unicode true
+ManifestSupportedOS all
+ManifestDPIAware true
+
+!addplugindir ./
+
+; Variables
+Var TempMaintServiceName
+Var BrandFullNameDA
+Var BrandFullName
+
+; Other included files may depend upon these includes!
+; The following includes are provided by NSIS.
+!include FileFunc.nsh
+!include LogicLib.nsh
+!include MUI.nsh
+!include WinMessages.nsh
+!include WinVer.nsh
+!include WordFunc.nsh
+
+!insertmacro GetOptions
+!insertmacro GetParameters
+!insertmacro GetSize
+
+; The test machines use this fallback key to run tests.
+; And anyone that wants to run tests themselves should already have 
+; this installed.
+!define FallbackKey \
+  "SOFTWARE\Mozilla\MaintenanceService\3932ecacee736d366d6436db0f55bce4"
+
+!define CompanyName "Mozilla Corporation"
+!define BrandFullNameInternal ""
+
+; The following includes are custom.
+!include defines.nsi
+; We keep defines.nsi defined so that we get other things like 
+; the version number, but we redefine BrandFullName
+!define MaintFullName "Mozilla Maintenance Service"
+!ifdef BrandFullName
+!undef BrandFullName
+!endif
+!define BrandFullName "${MaintFullName}"
+
+!include common.nsh
+!include locales.nsi
+
+VIAddVersionKey "FileDescription" "${MaintFullName} Installer"
+VIAddVersionKey "OriginalFilename" "maintenanceservice_installer.exe"
+
+Name "${MaintFullName}"
+OutFile "maintenanceservice_installer.exe"
+
+; Get installation folder from registry if available
+InstallDirRegKey HKLM "Software\Mozilla\MaintenanceService" ""
+
+SetOverwrite on
+
+!define MaintUninstallKey \
+ "Software\Microsoft\Windows\CurrentVersion\Uninstall\MozillaMaintenanceService"
+
+; Always install into the 32-bit location even if we have a 64-bit build.
+; This is because we use only 1 service for all Firefox channels.
+; Allow either x86 and x64 builds to exist at this location, depending on
+; what is the latest build.
+InstallDir "$PROGRAMFILES32\${MaintFullName}\"
+ShowUnInstDetails nevershow
+
+################################################################################
+# Modern User Interface - MUI
+
+!define MUI_ICON setup.ico
+!define MUI_UNICON setup.ico
+!define MUI_WELCOMEPAGE_TITLE_3LINES
+!define MUI_UNWELCOMEFINISHPAGE_BITMAP wizWatermark.bmp
+
+;Interface Settings
+!define MUI_ABORTWARNING
+
+; Uninstaller Pages
+!insertmacro MUI_UNPAGE_CONFIRM
+!insertmacro MUI_UNPAGE_INSTFILES
+
+################################################################################
+# Language
+
+!insertmacro MOZ_MUI_LANGUAGE 'baseLocale'
+!verbose push
+!verbose 3
+!include "overrideLocale.nsh"
+!include "customLocale.nsh"
+!verbose pop
+
+; Set this after the locale files to override it if it is in the locale
+; using " " for BrandingText will hide the "Nullsoft Install System..." branding
+BrandingText " "
+
+Function .onInit
+  ; Remove the current exe directory from the search order.
+  ; This only effects LoadLibrary calls and not implicitly loaded DLLs.
+  System::Call 'kernel32::SetDllDirectoryW(w "")'
+
+  SetSilent silent
+  ${Unless} ${AtLeastWin7}
+    Abort
+  ${EndUnless}
+FunctionEnd
+
+Function un.onInit
+  ; Remove the current exe directory from the search order.
+  ; This only effects LoadLibrary calls and not implicitly loaded DLLs.
+  System::Call 'kernel32::SetDllDirectoryW(w "")'
+
+  StrCpy $BrandFullNameDA "${MaintFullName}"
+  StrCpy $BrandFullName "${MaintFullName}"
+FunctionEnd
+
+Section "MaintenanceService"
+  AllowSkipFiles off
+
+  CreateDirectory $INSTDIR
+  SetOutPath $INSTDIR
+
+  ; If the service already exists, then it will be stopped when upgrading it
+  ; via the maintenanceservice_tmp.exe command executed below.
+  ; The maintenanceservice_tmp.exe command will rename the file to
+  ; maintenanceservice.exe if maintenanceservice_tmp.exe is newer.
+  ; If the service does not exist yet, we install it and drop the file on
+  ; disk as maintenanceservice.exe directly.
+  StrCpy $TempMaintServiceName "maintenanceservice.exe"
+  IfFileExists "$INSTDIR\maintenanceservice.exe" 0 skipAlreadyExists
+    StrCpy $TempMaintServiceName "maintenanceservice_tmp.exe"
+  skipAlreadyExists:
+
+  ; We always write out a copy and then decide whether to install it or 
+  ; not via calling its 'install' cmdline which works by version comparison.
+  CopyFiles "$EXEDIR\maintenanceservice.exe" "$INSTDIR\$TempMaintServiceName"
+
+  ; The updater.ini file is only used when performing an install or upgrade,
+  ; and only if that install or upgrade is successful.  If an old updater.ini
+  ; happened to be copied into the maintenance service installation directory
+  ; but the service was not newer, the updater.ini file would be unused.
+  ; It is used to fill the description of the service on success.
+  CopyFiles "$EXEDIR\updater.ini" "$INSTDIR\updater.ini"
+
+  ; Install the application maintenance service.
+  ; If a service already exists, the command line parameter will stop the
+  ; service and only install itself if it is newer than the already installed
+  ; service.  If successful it will remove the old maintenanceservice.exe
+  ; and replace it with maintenanceservice_tmp.exe.
+  ClearErrors
+  ;${GetParameters} $0
+  ;${GetOptions} "$0" "/Upgrade" $0
+  ;${If} ${Errors}
+    ExecWait '"$INSTDIR\$TempMaintServiceName" forceinstall'
+  ;${Else}
+    ; The upgrade cmdline is the same as install except
+    ; It will fail if the service isn't already installed.
+  ;  ExecWait '"$INSTDIR\$TempMaintServiceName" upgrade'
+  ;${EndIf}
+
+  WriteUninstaller "$INSTDIR\Uninstall.exe"
+  WriteRegStr HKLM "${MaintUninstallKey}" "DisplayName" "${MaintFullName}"
+  WriteRegStr HKLM "${MaintUninstallKey}" "UninstallString" \
+                   '"$INSTDIR\uninstall.exe"'
+  WriteRegStr HKLM "${MaintUninstallKey}" "DisplayIcon" \
+                   "$INSTDIR\Uninstall.exe,0"
+  WriteRegStr HKLM "${MaintUninstallKey}" "DisplayVersion" "${AppVersion}"
+  WriteRegStr HKLM "${MaintUninstallKey}" "Publisher" "Mozilla"
+  WriteRegStr HKLM "${MaintUninstallKey}" "Comments" "${BrandFullName}"
+  WriteRegDWORD HKLM "${MaintUninstallKey}" "NoModify" 1
+  ${GetSize} "$INSTDIR" "/S=0K" $R2 $R3 $R4
+  WriteRegDWORD HKLM "${MaintUninstallKey}" "EstimatedSize" $R2
+
+  ; Write out that a maintenance service was attempted.
+  ; We do this because on upgrades we will check this value and we only
+  ; want to install once on the first upgrade to maintenance service.
+  ; Also write out that we are currently installed, preferences will check
+  ; this value to determine if we should show the service update pref.
+  ; Since the Maintenance service can be installed either x86 or x64,
+  ; always use the 64-bit registry for checking if an attempt was made.
+  ${If} ${RunningX64}
+  ${OrIf} ${IsNativeARM64}
+    SetRegView 64
+  ${EndIf}
+  WriteRegDWORD HKLM "Software\Mozilla\MaintenanceService" "Attempted" 1
+  WriteRegDWORD HKLM "Software\Mozilla\MaintenanceService" "Installed" 1
+  DeleteRegValue HKLM "Software\Mozilla\MaintenanceService" "FFPrefetchDisabled"
+
+  ; Included here for debug purposes only.  
+  ; These keys are used to bypass the installation dir is a valid installation
+  ; check from the service so that tests can be run.
+  WriteRegStr HKLM "${FallbackKey}\0" "name" "Mozilla Corporation"
+  WriteRegStr HKLM "${FallbackKey}\0" "issuer" "DigiCert SHA2 Assured ID Code Signing CA"
+  WriteRegStr HKLM "${FallbackKey}\1" "name" "Mozilla Fake SPC"
+  WriteRegStr HKLM "${FallbackKey}\1" "issuer" "Mozilla Fake CA"
+  ${If} ${RunningX64}
+  ${OrIf} ${IsNativeARM64}
+    SetRegView lastused
+  ${EndIf}
+SectionEnd
+
+; By renaming before deleting we improve things slightly in case
+; there is a file in use error. In this case a new install can happen.
+Function un.RenameDelete
+  Pop $9
+  ; If the .moz-delete file already exists previously, delete it
+  ; If it doesn't exist, the call is ignored.
+  ; We don't need to pass /REBOOTOK here since it was already marked that way
+  ; if it exists.
+  Delete "$9.moz-delete"
+  Rename "$9" "$9.moz-delete"
+  ${If} ${Errors}
+    Delete /REBOOTOK "$9"
+  ${Else} 
+    Delete /REBOOTOK "$9.moz-delete"
+  ${EndIf}
+  ClearErrors
+FunctionEnd
+
+Section "Uninstall"
+  ; Delete the service so that no updates will be attempted
+  ExecWait '"$INSTDIR\maintenanceservice.exe" uninstall'
+
+  Push "$INSTDIR\updater.ini"
+  Call un.RenameDelete
+  Push "$INSTDIR\maintenanceservice.exe"
+  Call un.RenameDelete
+  Push "$INSTDIR\maintenanceservice_tmp.exe"
+  Call un.RenameDelete
+  Push "$INSTDIR\maintenanceservice.old"
+  Call un.RenameDelete
+  Push "$INSTDIR\Uninstall.exe"
+  Call un.RenameDelete
+  Push "$INSTDIR\update\updater.ini"
+  Call un.RenameDelete
+  Push "$INSTDIR\update\updater.exe"
+  Call un.RenameDelete
+  RMDir /REBOOTOK "$INSTDIR\update"
+  RMDir /REBOOTOK "$INSTDIR"
+  DeleteRegKey HKLM "${MaintUninstallKey}"
+
+  ${If} ${RunningX64}
+  ${OrIf} ${IsNativeARM64}
+    SetRegView 64
+  ${EndIf}
+  DeleteRegValue HKLM "Software\Mozilla\MaintenanceService" "Installed"
+  DeleteRegValue HKLM "Software\Mozilla\MaintenanceService" "FFPrefetchDisabled"
+  DeleteRegKey HKLM "${FallbackKey}\"
+  ${If} ${RunningX64}
+  ${OrIf} ${IsNativeARM64}
+    SetRegView lastused
+  ${EndIf}
+SectionEnd
+
diff --git a/toolkit/components/maintenanceservice/maintenanceservice.cpp b/toolkit/components/maintenanceservice/maintenanceservice.cpp
new file mode 100644
index 0000000000..d46feb1fc7
--- /dev/null
+++ b/toolkit/components/maintenanceservice/maintenanceservice.cpp
@@ -0,0 +1,370 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <windows.h>
+#include <shlwapi.h>
+#include <stdio.h>
+#include <wchar.h>
+#include <shlobj.h>
+
+#include "serviceinstall.h"
+#include "maintenanceservice.h"
+#include "servicebase.h"
+#include "workmonitor.h"
+#include "uachelper.h"
+#include "updatehelper.h"
+#include "registrycertificates.h"
+
+// Link w/ subsystem window so we don't get a console when executing
+// this binary through the installer.
+#pragma comment(linker, "/SUBSYSTEM:windows")
+
+SERVICE_STATUS gSvcStatus = {0};
+SERVICE_STATUS_HANDLE gSvcStatusHandle = nullptr;
+HANDLE gWorkDoneEvent = nullptr;
+HANDLE gThread = nullptr;
+bool gServiceControlStopping = false;
+
+// logs are pretty small, about 20 lines, so 10 seems reasonable.
+#define LOGS_TO_KEEP 10
+
+BOOL GetLogDirectoryPath(WCHAR* path);
+
+int wmain(int argc, WCHAR** argv) {
+  // If command-line parameter is "install", install the service
+  // or upgrade if already installed
+  // If command line parameter is "forceinstall", install the service
+  // even if it is older than what is already installed.
+  // If command-line parameter is "upgrade", upgrade the service
+  // but do not install it if it is not already installed.
+  // If command line parameter is "uninstall", uninstall the service.
+  // Otherwise, the service is probably being started by the SCM.
+  bool forceInstall = !lstrcmpi(argv[1], L"forceinstall");
+  if (!lstrcmpi(argv[1], L"install") || forceInstall) {
+    WCHAR logFilePath[MAX_PATH + 1];
+    if (GetLogDirectoryPath(logFilePath) &&
+        PathAppendSafe(logFilePath, L"maintenanceservice-install.log")) {
+      LogInit(logFilePath);
+    }
+
+    SvcInstallAction action = InstallSvc;
+    if (forceInstall) {
+      action = ForceInstallSvc;
+      LOG(("Installing service with force specified..."));
+    } else {
+      LOG(("Installing service..."));
+    }
+
+    bool ret = SvcInstall(action);
+    if (!ret) {
+      LOG_WARN(("Could not install service.  (%lu)", GetLastError()));
+      LogFinish();
+      return 1;
+    }
+
+    LOG(("The service was installed successfully"));
+    LogFinish();
+    return 0;
+  }
+
+  if (!lstrcmpi(argv[1], L"upgrade")) {
+    WCHAR logFilePath[MAX_PATH + 1];
+    if (GetLogDirectoryPath(logFilePath) &&
+        PathAppendSafe(logFilePath, L"maintenanceservice-install.log")) {
+      LogInit(logFilePath);
+    }
+
+    LOG(("Upgrading service if installed..."));
+    if (!SvcInstall(UpgradeSvc)) {
+      LOG_WARN(("Could not upgrade service.  (%lu)", GetLastError()));
+      LogFinish();
+      return 1;
+    }
+
+    LOG(("The service was upgraded successfully"));
+    LogFinish();
+    return 0;
+  }
+
+  if (!lstrcmpi(argv[1], L"uninstall")) {
+    WCHAR logFilePath[MAX_PATH + 1];
+    if (GetLogDirectoryPath(logFilePath) &&
+        PathAppendSafe(logFilePath, L"maintenanceservice-uninstall.log")) {
+      LogInit(logFilePath);
+    }
+    LOG(("Uninstalling service..."));
+    if (!SvcUninstall()) {
+      LOG_WARN(("Could not uninstall service.  (%lu)", GetLastError()));
+      LogFinish();
+      return 1;
+    }
+    LOG(("The service was uninstalled successfully"));
+    LogFinish();
+    return 0;
+  }
+
+  if (!lstrcmpi(argv[1], L"check-cert") && argc > 2) {
+    return DoesBinaryMatchAllowedCertificates(argv[2], argv[3], FALSE) ? 0 : 1;
+  }
+
+  SERVICE_TABLE_ENTRYW DispatchTable[] = {
+      {const_cast<LPWSTR>(SVC_NAME),
+       (LPSERVICE_MAIN_FUNCTIONW)SvcMain},  // -Wwritable-strings
+      {nullptr, nullptr}};
+
+  // This call returns when the service has stopped.
+  // The process should simply terminate when the call returns.
+  if (!StartServiceCtrlDispatcherW(DispatchTable)) {
+    LOG_WARN(("StartServiceCtrlDispatcher failed.  (%lu)", GetLastError()));
+  }
+
+  return 0;
+}
+
+/**
+ * Obtains the base path where logs should be stored
+ *
+ * @param  path The out buffer for the backup log path of size MAX_PATH + 1
+ * @return TRUE if successful.
+ */
+BOOL GetLogDirectoryPath(WCHAR* path) {
+  if (!GetModuleFileNameW(nullptr, path, MAX_PATH)) {
+    return FALSE;
+  }
+
+  if (!PathRemoveFileSpecW(path)) {
+    return FALSE;
+  }
+
+  if (!PathAppendSafe(path, L"logs")) {
+    return FALSE;
+  }
+  CreateDirectoryW(path, nullptr);
+  return TRUE;
+}
+
+/**
+ * Calculated a backup path based on the log number.
+ *
+ * @param  path      The out buffer to store the log path of size MAX_PATH + 1
+ * @param  basePath  The base directory where the calculated path should go
+ * @param  logNumber The log number, 0 == updater.log
+ * @return TRUE if successful.
+ */
+BOOL GetBackupLogPath(LPWSTR path, LPCWSTR basePath, int logNumber) {
+  WCHAR logName[64] = {L'\0'};
+  wcsncpy(path, basePath, sizeof(logName) / sizeof(logName[0]) - 1);
+  if (logNumber <= 0) {
+    swprintf(logName, sizeof(logName) / sizeof(logName[0]),
+             L"maintenanceservice.log");
+  } else {
+    swprintf(logName, sizeof(logName) / sizeof(logName[0]),
+             L"maintenanceservice-%d.log", logNumber);
+  }
+  return PathAppendSafe(path, logName);
+}
+
+/**
+ * Moves the old log files out of the way before a new one is written.
+ * If you for example keep 3 logs, then this function will do:
+ *   updater2.log -> updater3.log
+ *   updater1.log -> updater2.log
+ *   updater.log -> updater1.log
+ * Which clears room for a new updater.log in the basePath directory
+ *
+ * @param basePath      The base directory path where log files are stored
+ * @param numLogsToKeep The number of logs to keep
+ */
+void BackupOldLogs(LPCWSTR basePath, int numLogsToKeep) {
+  WCHAR oldPath[MAX_PATH + 1];
+  WCHAR newPath[MAX_PATH + 1];
+  for (int i = numLogsToKeep; i >= 1; i--) {
+    if (!GetBackupLogPath(oldPath, basePath, i - 1)) {
+      continue;
+    }
+
+    if (!GetBackupLogPath(newPath, basePath, i)) {
+      continue;
+    }
+
+    if (!MoveFileExW(oldPath, newPath, MOVEFILE_REPLACE_EXISTING)) {
+      continue;
+    }
+  }
+}
+
+/**
+ * Ensures the service is shutdown once all work is complete.
+ * There is an issue on XP SP2 and below where the service can hang
+ * in a stop pending state even though the SCM is notified of a stopped
+ * state.  Control *should* be returned to StartServiceCtrlDispatcher from the
+ * call to SetServiceStatus on a stopped state in the wmain thread.
+ * Sometimes this is not the case though. This thread will terminate the process
+ * if it has been 5 seconds after all work is done and the process is still not
+ * terminated.  This thread is only started once a stopped state was sent to the
+ * SCM. The stop pending hang can be reproduced intermittently even if you set
+ * a stopped state dirctly and never set a stop pending state.  It is safe to
+ * forcefully terminate the process ourselves since all work is done once we
+ * start this thread.
+ */
+DWORD WINAPI EnsureProcessTerminatedThread(LPVOID) {
+  Sleep(5000);
+  exit(0);
+}
+
+void StartTerminationThread() {
+  // If the process does not self terminate like it should, this thread
+  // will terminate the process after 5 seconds.
+  HANDLE thread = CreateThread(nullptr, 0, EnsureProcessTerminatedThread,
+                               nullptr, 0, nullptr);
+  if (thread) {
+    CloseHandle(thread);
+  }
+}
+
+/**
+ * Main entry point when running as a service.
+ */
+void WINAPI SvcMain(DWORD argc, LPWSTR* argv) {
+  // Setup logging, and backup the old logs
+  WCHAR logFilePath[MAX_PATH + 1];
+  if (GetLogDirectoryPath(logFilePath)) {
+    BackupOldLogs(logFilePath, LOGS_TO_KEEP);
+    if (PathAppendSafe(logFilePath, L"maintenanceservice.log")) {
+      LogInit(logFilePath);
+    }
+  }
+
+  // Disable every privilege we don't need. Processes started using
+  // CreateProcess will use the same token as this process.
+  UACHelper::DisablePrivileges(nullptr);
+
+  // Register the handler function for the service
+  gSvcStatusHandle = RegisterServiceCtrlHandlerW(SVC_NAME, SvcCtrlHandler);
+  if (!gSvcStatusHandle) {
+    LOG_WARN(("RegisterServiceCtrlHandler failed.  (%lu)", GetLastError()));
+    ExecuteServiceCommand(argc, argv);
+    LogFinish();
+    exit(1);
+  }
+
+  // These values will be re-used later in calls involving gSvcStatus
+  gSvcStatus.dwServiceType = SERVICE_WIN32_OWN_PROCESS;
+  gSvcStatus.dwServiceSpecificExitCode = 0;
+
+  // Report initial status to the SCM
+  ReportSvcStatus(SERVICE_START_PENDING, NO_ERROR, 3000);
+
+  // This event will be used to tell the SvcCtrlHandler when the work is
+  // done for when a stop comamnd is manually issued.
+  gWorkDoneEvent = CreateEvent(nullptr, TRUE, FALSE, nullptr);
+  if (!gWorkDoneEvent) {
+    ReportSvcStatus(SERVICE_STOPPED, 1, 0);
+    StartTerminationThread();
+    return;
+  }
+
+  // Initialization complete and we're about to start working on
+  // the actual command.  Report the service state as running to the SCM.
+  ReportSvcStatus(SERVICE_RUNNING, NO_ERROR, 0);
+
+  // The service command was executed, stop logging and set an event
+  // to indicate the work is done in case someone is waiting on a
+  // service stop operation.
+  BOOL success = ExecuteServiceCommand(argc, argv);
+  LogFinish();
+
+  SetEvent(gWorkDoneEvent);
+
+  // If we aren't already in a stopping state then tell the SCM we're stopped
+  // now.  If we are already in a stopping state then the SERVICE_STOPPED state
+  // will be set by the SvcCtrlHandler.
+  if (!gServiceControlStopping) {
+    ReportSvcStatus(SERVICE_STOPPED, success ? NO_ERROR : 1, 0);
+    StartTerminationThread();
+  }
+}
+
+/**
+ * Sets the current service status and reports it to the SCM.
+ *
+ * @param currentState  The current state (see SERVICE_STATUS)
+ * @param exitCode      The system error code
+ * @param waitHint      Estimated time for pending operation in milliseconds
+ */
+void ReportSvcStatus(DWORD currentState, DWORD exitCode, DWORD waitHint) {
+  static DWORD dwCheckPoint = 1;
+
+  gSvcStatus.dwCurrentState = currentState;
+  gSvcStatus.dwWin32ExitCode = exitCode;
+  gSvcStatus.dwWaitHint = waitHint;
+
+  if (SERVICE_START_PENDING == currentState ||
+      SERVICE_STOP_PENDING == currentState) {
+    gSvcStatus.dwControlsAccepted = 0;
+  } else {
+    gSvcStatus.dwControlsAccepted =
+        SERVICE_ACCEPT_STOP | SERVICE_ACCEPT_SHUTDOWN;
+  }
+
+  if ((SERVICE_RUNNING == currentState) || (SERVICE_STOPPED == currentState)) {
+    gSvcStatus.dwCheckPoint = 0;
+  } else {
+    gSvcStatus.dwCheckPoint = dwCheckPoint++;
+  }
+
+  // Report the status of the service to the SCM.
+  SetServiceStatus(gSvcStatusHandle, &gSvcStatus);
+}
+
+/**
+ * Since the SvcCtrlHandler should only spend at most 30 seconds before
+ * returning, this function does the service stop work for the SvcCtrlHandler.
+ */
+DWORD WINAPI StopServiceAndWaitForCommandThread(LPVOID) {
+  do {
+    ReportSvcStatus(SERVICE_STOP_PENDING, NO_ERROR, 1000);
+  } while (WaitForSingleObject(gWorkDoneEvent, 100) == WAIT_TIMEOUT);
+  CloseHandle(gWorkDoneEvent);
+  gWorkDoneEvent = nullptr;
+  ReportSvcStatus(SERVICE_STOPPED, NO_ERROR, 0);
+  StartTerminationThread();
+  return 0;
+}
+
+/**
+ * Called by SCM whenever a control code is sent to the service
+ * using the ControlService function.
+ */
+void WINAPI SvcCtrlHandler(DWORD dwCtrl) {
+  // After a SERVICE_CONTROL_STOP there should be no more commands sent to
+  // the SvcCtrlHandler.
+  if (gServiceControlStopping) {
+    return;
+  }
+
+  // Handle the requested control code.
+  switch (dwCtrl) {
+    case SERVICE_CONTROL_SHUTDOWN:
+    case SERVICE_CONTROL_STOP: {
+      gServiceControlStopping = true;
+      ReportSvcStatus(SERVICE_STOP_PENDING, NO_ERROR, 1000);
+
+      // The SvcCtrlHandler thread should not spend more than 30 seconds in
+      // shutdown so we spawn a new thread for stopping the service
+      HANDLE thread = CreateThread(
+          nullptr, 0, StopServiceAndWaitForCommandThread, nullptr, 0, nullptr);
+      if (thread) {
+        CloseHandle(thread);
+      } else {
+        // Couldn't start the thread so just call the stop ourselves.
+        // If it happens to take longer than 30 seconds the caller will
+        // get an error.
+        StopServiceAndWaitForCommandThread(nullptr);
+      }
+    } break;
+    default:
+      break;
+  }
+}
diff --git a/toolkit/components/maintenanceservice/maintenanceservice.exe.manifest b/toolkit/components/maintenanceservice/maintenanceservice.exe.manifest
new file mode 100644
index 0000000000..e6bfba8ca5
--- /dev/null
+++ b/toolkit/components/maintenanceservice/maintenanceservice.exe.manifest
@@ -0,0 +1,25 @@
+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<assembly xmlns="urn:schemas-microsoft-com:asm.v1" manifestVersion="1.0">
+<assemblyIdentity
+        version="1.0.0.0"
+        processorArchitecture="*"
+        name="MaintenanceService"
+        type="win32"
+/>
+<description>MaintenanceService</description>
+<ms_asmv3:trustInfo xmlns:ms_asmv3="urn:schemas-microsoft-com:asm.v3">
+  <ms_asmv3:security>
+    <ms_asmv3:requestedPrivileges>
+      <ms_asmv3:requestedExecutionLevel level="requireAdministrator" uiAccess="false" />
+    </ms_asmv3:requestedPrivileges>
+  </ms_asmv3:security>
+</ms_asmv3:trustInfo>
+  <compatibility xmlns="urn:schemas-microsoft-com:compatibility.v1">
+    <application>
+      <supportedOS Id="{8e0f7a12-bfb3-4fe8-b9a5-48fd50a15a9a}"/>
+      <supportedOS Id="{1f676c76-80e1-4239-95bb-83d0f6d0da78}"/>
+      <supportedOS Id="{4a2f28e3-53b9-4441-ba9c-d69d4a4a6e38}"/>
+      <supportedOS Id="{35138b9a-5d96-4fbd-8e2d-a2440225f93a}"/>
+    </application>
+  </compatibility>
+</assembly>
diff --git a/toolkit/components/maintenanceservice/maintenanceservice.h b/toolkit/components/maintenanceservice/maintenanceservice.h
new file mode 100644
index 0000000000..596b2b44ee
--- /dev/null
+++ b/toolkit/components/maintenanceservice/maintenanceservice.h
@@ -0,0 +1,16 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef TOOLKIT_COMPONENTS_MAINTENANCESERVICE_MAINTENANCESERVICE_H_
+#define TOOLKIT_COMPONENTS_MAINTENANCESERVICE_MAINTENANCESERVICE_H_
+
+#include <windows.h>
+
+void WINAPI SvcMain(DWORD dwArgc, LPWSTR* lpszArgv);
+void SvcInit(DWORD dwArgc, LPWSTR* lpszArgv);
+void WINAPI SvcCtrlHandler(DWORD dwCtrl);
+void ReportSvcStatus(DWORD dwCurrentState, DWORD dwWin32ExitCode,
+                     DWORD dwWaitHint);
+
+#endif  // TOOLKIT_COMPONENTS_MAINTENANCESERVICE_MAINTENANCESERVICE_H_
diff --git a/toolkit/components/maintenanceservice/maintenanceservice.rc b/toolkit/components/maintenanceservice/maintenanceservice.rc
new file mode 100644
index 0000000000..e3731efb2a
--- /dev/null
+++ b/toolkit/components/maintenanceservice/maintenanceservice.rc
@@ -0,0 +1,79 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Microsoft Visual C++ generated resource script.
+//
+#include "resource.h"
+
+#define APSTUDIO_READONLY_SYMBOLS
+/////////////////////////////////////////////////////////////////////////////
+//
+// Generated from the TEXTINCLUDE 2 resource.
+//
+#include "winresrc.h"
+
+/////////////////////////////////////////////////////////////////////////////
+#undef APSTUDIO_READONLY_SYMBOLS
+
+/////////////////////////////////////////////////////////////////////////////
+// English (U.S.) resources
+
+#if !defined(AFX_RESOURCE_DLL) || defined(AFX_TARG_ENU)
+#ifdef _WIN32
+LANGUAGE LANG_ENGLISH, SUBLANG_ENGLISH_US
+#pragma code_page(1252)
+#endif //_WIN32
+
+/////////////////////////////////////////////////////////////////////////////
+//
+// DESIGNINFO
+//
+
+#ifdef APSTUDIO_INVOKED
+GUIDELINES DESIGNINFO 
+BEGIN
+END
+#endif    // APSTUDIO_INVOKED
+
+
+#ifdef APSTUDIO_INVOKED
+/////////////////////////////////////////////////////////////////////////////
+//
+// TEXTINCLUDE
+//
+
+1 TEXTINCLUDE 
+BEGIN
+    "resource.h\0"
+END
+
+2 TEXTINCLUDE 
+BEGIN
+    "#include ""winresrc.h""\r\n"
+    "\0"
+END
+
+3 TEXTINCLUDE 
+BEGIN
+    "\r\n"
+    "\0"
+END
+
+#endif    // APSTUDIO_INVOKED
+
+#endif    // English (U.S.) resources
+/////////////////////////////////////////////////////////////////////////////
+
+
+
+#ifndef APSTUDIO_INVOKED
+/////////////////////////////////////////////////////////////////////////////
+//
+// Generated from the TEXTINCLUDE 3 resource.
+//
+
+
+/////////////////////////////////////////////////////////////////////////////
+#endif    // not APSTUDIO_INVOKED
+
diff --git a/toolkit/components/maintenanceservice/moz.build b/toolkit/components/maintenanceservice/moz.build
new file mode 100644
index 0000000000..ee9a106259
--- /dev/null
+++ b/toolkit/components/maintenanceservice/moz.build
@@ -0,0 +1,62 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+Program("maintenanceservice")
+
+SOURCES += [
+    "maintenanceservice.cpp",
+    "servicebase.cpp",
+    "serviceinstall.cpp",
+    "workmonitor.cpp",
+]
+
+USE_LIBS += [
+    "updatecommon",
+]
+
+if CONFIG["DISABLE_UPDATER_AUTHENTICODE_CHECK"]:
+    DEFINES["DISABLE_UPDATER_AUTHENTICODE_CHECK"] = True
+
+DEFINES["UNICODE"] = True
+DEFINES["_UNICODE"] = True
+DEFINES["NS_NO_XPCOM"] = True
+
+# Pick up nsWindowsRestart.cpp
+LOCAL_INCLUDES += [
+    "/toolkit/mozapps/update/common",
+    "/toolkit/xre",
+]
+
+USE_STATIC_LIBS = True
+
+if CONFIG["CC_TYPE"] == "clang-cl":
+    WIN32_EXE_LDFLAGS += ["-ENTRY:wmainCRTStartup"]
+
+if CONFIG["OS_TARGET"] == "WINNT" and CONFIG["CC_TYPE"] in ("gcc", "clang"):
+    # This allows us to use wmain as the entry point on mingw
+    LDFLAGS += [
+        "-municode",
+    ]
+
+RCINCLUDE = "maintenanceservice.rc"
+
+DisableStlWrapping()
+
+OS_LIBS += [
+    "comctl32",
+    "ws2_32",
+    "shell32",
+    "shlwapi",
+    "user32",
+    "userenv",
+    "uuid",
+]
+
+if CONFIG["ENABLE_TESTS"]:
+    DIRS += ["tests/gtest"]
+
+with Files("**"):
+    BUG_COMPONENT = ("Toolkit", "Application Update")
diff --git a/toolkit/components/maintenanceservice/resource.h b/toolkit/components/maintenanceservice/resource.h
new file mode 100644
index 0000000000..fcc79dd9ae
--- /dev/null
+++ b/toolkit/components/maintenanceservice/resource.h
@@ -0,0 +1,20 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+//{{NO_DEPENDENCIES}}
+// Microsoft Visual C++ generated include file.
+// Used by updater.rc
+//
+#define IDI_DIALOG 1003
+
+// Next default values for new objects
+//
+#ifdef APSTUDIO_INVOKED
+#  ifndef APSTUDIO_READONLY_SYMBOLS
+#    define _APS_NEXT_RESOURCE_VALUE 102
+#    define _APS_NEXT_COMMAND_VALUE 40001
+#    define _APS_NEXT_CONTROL_VALUE 1003
+#    define _APS_NEXT_SYMED_VALUE 101
+#  endif
+#endif
diff --git a/toolkit/components/maintenanceservice/servicebase.cpp b/toolkit/components/maintenanceservice/servicebase.cpp
new file mode 100644
index 0000000000..d6004234c7
--- /dev/null
+++ b/toolkit/components/maintenanceservice/servicebase.cpp
@@ -0,0 +1,84 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "servicebase.h"
+#include "nsWindowsHelpers.h"
+
+// Shared code between applications and updater.exe
+#include "nsWindowsRestart.cpp"
+
+/**
+ * Verifies if 2 files are byte for byte equivalent.
+ *
+ * @param  file1Path   The first file to verify.
+ * @param  file2Path   The second file to verify.
+ * @param  sameContent Out parameter, TRUE if the files are equal
+ * @return TRUE If there was no error checking the files.
+ */
+BOOL VerifySameFiles(LPCWSTR file1Path, LPCWSTR file2Path, BOOL& sameContent) {
+  sameContent = FALSE;
+  nsAutoHandle file1(CreateFileW(file1Path, GENERIC_READ, FILE_SHARE_READ,
+                                 nullptr, OPEN_EXISTING, 0, nullptr));
+  if (INVALID_HANDLE_VALUE == file1) {
+    return FALSE;
+  }
+  nsAutoHandle file2(CreateFileW(file2Path, GENERIC_READ, FILE_SHARE_READ,
+                                 nullptr, OPEN_EXISTING, 0, nullptr));
+  if (INVALID_HANDLE_VALUE == file2) {
+    return FALSE;
+  }
+
+  DWORD fileSize1 = GetFileSize(file1, nullptr);
+  DWORD fileSize2 = GetFileSize(file2, nullptr);
+  if (INVALID_FILE_SIZE == fileSize1 || INVALID_FILE_SIZE == fileSize2) {
+    return FALSE;
+  }
+
+  if (fileSize1 != fileSize2) {
+    // sameContent is already set to FALSE
+    return TRUE;
+  }
+
+  char buf1[COMPARE_BLOCKSIZE];
+  char buf2[COMPARE_BLOCKSIZE];
+  DWORD numBlocks = fileSize1 / COMPARE_BLOCKSIZE;
+  DWORD leftOver = fileSize1 % COMPARE_BLOCKSIZE;
+  DWORD readAmount;
+  for (DWORD i = 0; i < numBlocks; i++) {
+    if (!ReadFile(file1, buf1, COMPARE_BLOCKSIZE, &readAmount, nullptr) ||
+        readAmount != COMPARE_BLOCKSIZE) {
+      return FALSE;
+    }
+
+    if (!ReadFile(file2, buf2, COMPARE_BLOCKSIZE, &readAmount, nullptr) ||
+        readAmount != COMPARE_BLOCKSIZE) {
+      return FALSE;
+    }
+
+    if (memcmp(buf1, buf2, COMPARE_BLOCKSIZE)) {
+      // sameContent is already set to FALSE
+      return TRUE;
+    }
+  }
+
+  if (leftOver) {
+    if (!ReadFile(file1, buf1, leftOver, &readAmount, nullptr) ||
+        readAmount != leftOver) {
+      return FALSE;
+    }
+
+    if (!ReadFile(file2, buf2, leftOver, &readAmount, nullptr) ||
+        readAmount != leftOver) {
+      return FALSE;
+    }
+
+    if (memcmp(buf1, buf2, leftOver)) {
+      // sameContent is already set to FALSE
+      return TRUE;
+    }
+  }
+
+  sameContent = TRUE;
+  return TRUE;
+}
diff --git a/toolkit/components/maintenanceservice/servicebase.h b/toolkit/components/maintenanceservice/servicebase.h
new file mode 100644
index 0000000000..5ba3689a22
--- /dev/null
+++ b/toolkit/components/maintenanceservice/servicebase.h
@@ -0,0 +1,22 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <windows.h>
+#include "updatecommon.h"
+
+BOOL PathAppendSafe(LPWSTR base, LPCWSTR extra);
+BOOL VerifySameFiles(LPCWSTR file1Path, LPCWSTR file2Path, BOOL& sameContent);
+
+// 32KiB for comparing files at a time seems reasonable.
+// The bigger the better for speed, but this will be used
+// on the stack so I don't want it to be too big.
+#define COMPARE_BLOCKSIZE 32768
+
+// The following string resource value is used to uniquely identify the signed
+// Mozilla application as an updater.  Before the maintenance service will
+// execute the updater it must have this updater identity string in its string
+// table.  No other signed Mozilla product will have this string table value.
+#define UPDATER_IDENTITY_STRING \
+  "moz-updater.exe-4cdccec4-5ee0-4a06-9817-4cd899a9db49"
+#define IDS_UPDATER_IDENTITY 1006
diff --git a/toolkit/components/maintenanceservice/serviceinstall.cpp b/toolkit/components/maintenanceservice/serviceinstall.cpp
new file mode 100644
index 0000000000..c59a74b94a
--- /dev/null
+++ b/toolkit/components/maintenanceservice/serviceinstall.cpp
@@ -0,0 +1,760 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <windows.h>
+#include <aclapi.h>
+#include <stdlib.h>
+#include <shlwapi.h>
+
+// Used for DNLEN and UNLEN
+#include <lm.h>
+
+#include <nsWindowsHelpers.h>
+#include "mozilla/UniquePtr.h"
+
+#include "serviceinstall.h"
+#include "servicebase.h"
+#include "updatehelper.h"
+#include "shellapi.h"
+#include "readstrings.h"
+#include "updatererrors.h"
+#include "commonupdatedir.h"
+
+#pragma comment(lib, "version.lib")
+
+// This uninstall key is defined originally in maintenanceservice_installer.nsi
+#define MAINT_UNINSTALL_KEY                                                    \
+  L"Software\\Microsoft\\Windows\\CurrentVersion\\Uninstall\\MozillaMaintenan" \
+  L"ceService"
+
+static BOOL UpdateUninstallerVersionString(LPWSTR versionString) {
+  HKEY uninstallKey;
+  if (RegOpenKeyExW(HKEY_LOCAL_MACHINE, MAINT_UNINSTALL_KEY, 0,
+                    KEY_WRITE | KEY_WOW64_32KEY,
+                    &uninstallKey) != ERROR_SUCCESS) {
+    return FALSE;
+  }
+
+  LONG rv = RegSetValueExW(uninstallKey, L"DisplayVersion", 0, REG_SZ,
+                           reinterpret_cast<const BYTE*>(versionString),
+                           (wcslen(versionString) + 1) * sizeof(WCHAR));
+  RegCloseKey(uninstallKey);
+  return rv == ERROR_SUCCESS;
+}
+
+/**
+ * A wrapper function to read strings for the maintenance service.
+ *
+ * @param path    The path of the ini file to read from
+ * @param results The maintenance service strings that were read
+ * @return OK on success
+ */
+static int ReadMaintenanceServiceStrings(
+    LPCWSTR path, MaintenanceServiceStringTable* results) {
+  // Read in the maintenance service description string if specified.
+  const unsigned int kNumStrings = 1;
+  const char* kServiceKeys = "MozillaMaintenanceDescription\0";
+  mozilla::UniquePtr<char[]> serviceString;
+  int result = ReadStrings(path, kServiceKeys, kNumStrings, &serviceString);
+  if (result != OK) {
+    results->serviceDescription = mozilla::MakeUnique<char[]>(1);
+    results->serviceDescription.get()[0] = '\0';
+  }
+  results->serviceDescription.swap(serviceString);
+  return result;
+}
+
+/**
+ * Obtains the version number from the specified PE file's version information
+ * Version Format: A.B.C.D (Example 10.0.0.300)
+ *
+ * @param  path The path of the file to check the version on
+ * @param  A    The first part of the version number
+ * @param  B    The second part of the version number
+ * @param  C    The third part of the version number
+ * @param  D    The fourth part of the version number
+ * @return TRUE if successful
+ */
+static BOOL GetVersionNumberFromPath(LPWSTR path, DWORD& A, DWORD& B, DWORD& C,
+                                     DWORD& D) {
+  DWORD fileVersionInfoSize = GetFileVersionInfoSizeW(path, 0);
+  mozilla::UniquePtr<char[]> fileVersionInfo(new char[fileVersionInfoSize]);
+  if (!GetFileVersionInfoW(path, 0, fileVersionInfoSize,
+                           fileVersionInfo.get())) {
+    LOG_WARN(
+        ("Could not obtain file info of old service.  (%lu)", GetLastError()));
+    return FALSE;
+  }
+
+  VS_FIXEDFILEINFO* fixedFileInfo =
+      reinterpret_cast<VS_FIXEDFILEINFO*>(fileVersionInfo.get());
+  UINT size;
+  if (!VerQueryValueW(fileVersionInfo.get(), L"\\",
+                      reinterpret_cast<LPVOID*>(&fixedFileInfo), &size)) {
+    LOG_WARN(("Could not query file version info of old service.  (%lu)",
+              GetLastError()));
+    return FALSE;
+  }
+
+  A = HIWORD(fixedFileInfo->dwFileVersionMS);
+  B = LOWORD(fixedFileInfo->dwFileVersionMS);
+  C = HIWORD(fixedFileInfo->dwFileVersionLS);
+  D = LOWORD(fixedFileInfo->dwFileVersionLS);
+  return TRUE;
+}
+
+/**
+ * Updates the service description with what is stored in updater.ini
+ * at the same path as the currently executing module binary.
+ *
+ * @param serviceHandle A handle to an opened service with
+ *                      SERVICE_CHANGE_CONFIG access right
+ * @param TRUE on succcess.
+ */
+BOOL UpdateServiceDescription(SC_HANDLE serviceHandle) {
+  WCHAR updaterINIPath[MAX_PATH + 1];
+  if (!GetModuleFileNameW(nullptr, updaterINIPath,
+                          sizeof(updaterINIPath) / sizeof(updaterINIPath[0]))) {
+    LOG_WARN(
+        ("Could not obtain module filename when attempting to "
+         "modify service description.  (%lu)",
+         GetLastError()));
+    return FALSE;
+  }
+
+  if (!PathRemoveFileSpecW(updaterINIPath)) {
+    LOG_WARN(
+        ("Could not remove file spec when attempting to "
+         "modify service description.  (%lu)",
+         GetLastError()));
+    return FALSE;
+  }
+
+  if (!PathAppendSafe(updaterINIPath, L"updater.ini")) {
+    LOG_WARN(
+        ("Could not append updater.ini filename when attempting to "
+         "modify service description.  (%lu)",
+         GetLastError()));
+    return FALSE;
+  }
+
+  if (GetFileAttributesW(updaterINIPath) == INVALID_FILE_ATTRIBUTES) {
+    LOG_WARN(
+        ("updater.ini file does not exist, will not modify "
+         "service description.  (%lu)",
+         GetLastError()));
+    return FALSE;
+  }
+
+  MaintenanceServiceStringTable serviceStrings;
+  int rv = ReadMaintenanceServiceStrings(updaterINIPath, &serviceStrings);
+  if (rv != OK || !strlen(serviceStrings.serviceDescription.get())) {
+    LOG_WARN(
+        ("updater.ini file does not contain a maintenance "
+         "service description."));
+    return FALSE;
+  }
+
+  int bufferSize = MultiByteToWideChar(
+      CP_UTF8, 0, serviceStrings.serviceDescription.get(), -1, nullptr, 0);
+  mozilla::UniquePtr<WCHAR[]> serviceDescription =
+      mozilla::MakeUnique<WCHAR[]>(bufferSize);
+  if (!MultiByteToWideChar(CP_UTF8, 0, serviceStrings.serviceDescription.get(),
+                           -1, serviceDescription.get(), bufferSize)) {
+    LOG_WARN(("Could not convert description to wide string format.  (%lu)",
+              GetLastError()));
+    return FALSE;
+  }
+
+  SERVICE_DESCRIPTIONW descriptionConfig;
+  descriptionConfig.lpDescription = serviceDescription.get();
+  if (!ChangeServiceConfig2W(serviceHandle, SERVICE_CONFIG_DESCRIPTION,
+                             &descriptionConfig)) {
+    LOG_WARN(("Could not change service config.  (%lu)", GetLastError()));
+    return FALSE;
+  }
+
+  LOG(("The service description was updated successfully."));
+  return TRUE;
+}
+
+/**
+ * Determines if the MozillaMaintenance service path needs to be updated
+ * and fixes it if it is wrong.
+ *
+ * @param service             A handle to the service to fix.
+ * @param currentServicePath  The current (possibly wrong) path that is used.
+ * @param servicePathWasWrong Out parameter set to TRUE if a fix was needed.
+ * @return TRUE if the service path is now correct.
+ */
+BOOL FixServicePath(SC_HANDLE service, LPCWSTR currentServicePath,
+                    BOOL& servicePathWasWrong) {
+  // When we originally upgraded the MozillaMaintenance service we
+  // would uninstall the service on each upgrade.  This had an
+  // intermittent error which could cause the service to use the file
+  // maintenanceservice_tmp.exe as the install path.  Only a small number
+  // of Nightly users would be affected by this, but we check for this
+  // state here and fix the user if they are affected.
+  //
+  // We also fix the path in the case of the path not being quoted.
+  size_t currentServicePathLen = wcslen(currentServicePath);
+  bool doesServiceHaveCorrectPath =
+      currentServicePathLen > 2 &&
+      !wcsstr(currentServicePath, L"maintenanceservice_tmp.exe") &&
+      currentServicePath[0] == L'\"' &&
+      currentServicePath[currentServicePathLen - 1] == L'\"';
+
+  if (doesServiceHaveCorrectPath) {
+    LOG(("The MozillaMaintenance service path is correct."));
+    servicePathWasWrong = FALSE;
+    return TRUE;
+  }
+  // This is a recoverable situation so not logging as a warning
+  LOG(("The MozillaMaintenance path is NOT correct. It was: %ls",
+       currentServicePath));
+
+  servicePathWasWrong = TRUE;
+  WCHAR fixedPath[MAX_PATH + 1] = {L'\0'};
+  wcsncpy(fixedPath, currentServicePath, MAX_PATH);
+  PathUnquoteSpacesW(fixedPath);
+  if (!PathRemoveFileSpecW(fixedPath)) {
+    LOG_WARN(("Couldn't remove file spec.  (%lu)", GetLastError()));
+    return FALSE;
+  }
+  if (!PathAppendSafe(fixedPath, L"maintenanceservice.exe")) {
+    LOG_WARN(("Couldn't append file spec.  (%lu)", GetLastError()));
+    return FALSE;
+  }
+  PathQuoteSpacesW(fixedPath);
+
+  if (!ChangeServiceConfigW(service, SERVICE_NO_CHANGE, SERVICE_NO_CHANGE,
+                            SERVICE_NO_CHANGE, fixedPath, nullptr, nullptr,
+                            nullptr, nullptr, nullptr, nullptr)) {
+    LOG_WARN(("Could not fix service path.  (%lu)", GetLastError()));
+    return FALSE;
+  }
+
+  LOG(("Fixed service path to: %ls.", fixedPath));
+  return TRUE;
+}
+
+/**
+ * Installs or upgrades the SVC_NAME service.
+ * If an existing service is already installed, we replace it with the
+ * currently running process.
+ *
+ * @param  action The action to perform.
+ * @return TRUE if the service was installed/upgraded
+ */
+BOOL SvcInstall(SvcInstallAction action) {
+  // Get a handle to the local computer SCM database with full access rights.
+  nsAutoServiceHandle schSCManager(
+      OpenSCManager(nullptr, nullptr, SC_MANAGER_ALL_ACCESS));
+  if (!schSCManager) {
+    LOG_WARN(("Could not open service manager.  (%lu)", GetLastError()));
+    return FALSE;
+  }
+
+  WCHAR newServiceBinaryPath[MAX_PATH + 1];
+  if (!GetModuleFileNameW(
+          nullptr, newServiceBinaryPath,
+          sizeof(newServiceBinaryPath) / sizeof(newServiceBinaryPath[0]))) {
+    LOG_WARN(
+        ("Could not obtain module filename when attempting to "
+         "install service.  (%lu)",
+         GetLastError()));
+    return FALSE;
+  }
+
+  // Check if we already have the service installed.
+  nsAutoServiceHandle schService(
+      OpenServiceW(schSCManager, SVC_NAME, SERVICE_ALL_ACCESS));
+  DWORD lastError = GetLastError();
+  if (!schService && ERROR_SERVICE_DOES_NOT_EXIST != lastError) {
+    // The service exists but we couldn't open it
+    LOG_WARN(("Could not open service.  (%lu)", GetLastError()));
+    return FALSE;
+  }
+
+  if (schService) {
+    // The service exists but it may not have the correct permissions.
+    // This could happen if the permissions were not set correctly originally
+    // or have been changed after the installation.  This will reset the
+    // permissions back to allow limited user accounts.
+    if (!SetUserAccessServiceDACL(schService)) {
+      LOG_WARN(
+          ("Could not reset security ACE on service handle. It might not be "
+           "possible to start the service. This error should never "
+           "happen.  (%lu)",
+           GetLastError()));
+    }
+
+    // The service exists and we opened it
+    DWORD bytesNeeded;
+    if (!QueryServiceConfigW(schService, nullptr, 0, &bytesNeeded) &&
+        GetLastError() != ERROR_INSUFFICIENT_BUFFER) {
+      LOG_WARN(
+          ("Could not determine buffer size for query service config.  (%lu)",
+           GetLastError()));
+      return FALSE;
+    }
+
+    // Get the service config information, in particular we want the binary
+    // path of the service.
+    mozilla::UniquePtr<char[]> serviceConfigBuffer(new char[bytesNeeded]);
+    if (!QueryServiceConfigW(
+            schService,
+            reinterpret_cast<QUERY_SERVICE_CONFIGW*>(serviceConfigBuffer.get()),
+            bytesNeeded, &bytesNeeded)) {
+      LOG_WARN(("Could open service but could not query service config.  (%lu)",
+                GetLastError()));
+      return FALSE;
+    }
+    QUERY_SERVICE_CONFIGW& serviceConfig =
+        *reinterpret_cast<QUERY_SERVICE_CONFIGW*>(serviceConfigBuffer.get());
+
+    // Check if we need to fix the service path
+    BOOL servicePathWasWrong;
+    static BOOL alreadyCheckedFixServicePath = FALSE;
+    if (!alreadyCheckedFixServicePath) {
+      if (!FixServicePath(schService, serviceConfig.lpBinaryPathName,
+                          servicePathWasWrong)) {
+        LOG_WARN(
+            ("Could not fix service path. This should never happen.  (%lu)",
+             GetLastError()));
+        // True is returned because the service is pointing to
+        // maintenanceservice_tmp.exe so it actually was upgraded to the
+        // newest installed service.
+        return TRUE;
+      } else if (servicePathWasWrong) {
+        // Now that the path is fixed we should re-attempt the install.
+        // This current process' image path is maintenanceservice_tmp.exe.
+        // The service used to point to maintenanceservice_tmp.exe.
+        // The service was just fixed to point to maintenanceservice.exe.
+        // Re-attempting an install from scratch will work as normal.
+        alreadyCheckedFixServicePath = TRUE;
+        LOG(("Restarting install action: %d", action));
+        return SvcInstall(action);
+      }
+    }
+
+    // Ensure the service path is not quoted. We own this memory and know it to
+    // be large enough for the quoted path, so it is large enough for the
+    // unquoted path.  This function cannot fail.
+    PathUnquoteSpacesW(serviceConfig.lpBinaryPathName);
+
+    // Obtain the existing maintenanceservice file's version number and
+    // the new file's version number.  Versions are in the format of
+    // A.B.C.D.
+    DWORD existingA, existingB, existingC, existingD;
+    DWORD newA, newB, newC, newD;
+    BOOL obtainedExistingVersionInfo =
+        GetVersionNumberFromPath(serviceConfig.lpBinaryPathName, existingA,
+                                 existingB, existingC, existingD);
+    if (!GetVersionNumberFromPath(newServiceBinaryPath, newA, newB, newC,
+                                  newD)) {
+      LOG_WARN(("Could not obtain version number from new path"));
+      return FALSE;
+    }
+
+    // Check if we need to replace the old binary with the new one
+    // If we couldn't get the old version info then we assume we should
+    // replace it.
+    if (ForceInstallSvc == action || !obtainedExistingVersionInfo ||
+        (existingA < newA) || (existingA == newA && existingB < newB) ||
+        (existingA == newA && existingB == newB && existingC < newC) ||
+        (existingA == newA && existingB == newB && existingC == newC &&
+         existingD < newD)) {
+      // We have a newer updater, so update the description from the INI file.
+      UpdateServiceDescription(schService);
+
+      schService.reset();
+      if (!StopService()) {
+        return FALSE;
+      }
+
+      if (!wcscmp(newServiceBinaryPath, serviceConfig.lpBinaryPathName)) {
+        LOG(
+            ("File is already in the correct location, no action needed for "
+             "upgrade.  The path is: \"%ls\"",
+             newServiceBinaryPath));
+        return TRUE;
+      }
+
+      BOOL result = TRUE;
+
+      // Attempt to copy the new binary over top the existing binary.
+      // If there is an error we try to move it out of the way and then
+      // copy it in.  First try the safest / easiest way to overwrite the file.
+      if (!CopyFileW(newServiceBinaryPath, serviceConfig.lpBinaryPathName,
+                     FALSE)) {
+        LOG_WARN(
+            ("Could not overwrite old service binary file. "
+             "This should never happen, but if it does the next "
+             "upgrade will fix it, the service is not a critical "
+             "component that needs to be installed for upgrades "
+             "to work.  (%lu)",
+             GetLastError()));
+
+        // We rename the last 3 filename chars in an unsafe way.  Manually
+        // verify there are more than 3 chars for safe failure in MoveFileExW.
+        const size_t len = wcslen(serviceConfig.lpBinaryPathName);
+        if (len > 3) {
+          // Calculate the temp file path that we're moving the file to. This
+          // is the same as the proper service path but with a .old extension.
+          LPWSTR oldServiceBinaryTempPath = new WCHAR[len + 1];
+          memset(oldServiceBinaryTempPath, 0, (len + 1) * sizeof(WCHAR));
+          wcsncpy(oldServiceBinaryTempPath, serviceConfig.lpBinaryPathName,
+                  len);
+          // Rename the last 3 chars to 'old'
+          wcsncpy(oldServiceBinaryTempPath + len - 3, L"old", 3);
+
+          // Move the current (old) service file to the temp path.
+          if (MoveFileExW(serviceConfig.lpBinaryPathName,
+                          oldServiceBinaryTempPath,
+                          MOVEFILE_REPLACE_EXISTING | MOVEFILE_WRITE_THROUGH)) {
+            // The old binary is moved out of the way, copy in the new one.
+            if (!CopyFileW(newServiceBinaryPath, serviceConfig.lpBinaryPathName,
+                           FALSE)) {
+              // It is best to leave the old service binary in this condition.
+              LOG_WARN(
+                  ("The new service binary could not be copied in."
+                   " The service will not be upgraded."));
+              result = FALSE;
+            } else {
+              LOG(
+                  ("The new service binary was copied in by first moving the"
+                   " old one out of the way."));
+            }
+
+            // Attempt to get rid of the old service temp path.
+            if (DeleteFileW(oldServiceBinaryTempPath)) {
+              LOG(("The old temp service path was deleted: %ls.",
+                   oldServiceBinaryTempPath));
+            } else {
+              // The old temp path could not be removed.  It will be removed
+              // the next time the user can't copy the binary in or on
+              // uninstall.
+              LOG_WARN(("The old temp service path was not deleted."));
+            }
+          } else {
+            // It is best to leave the old service binary in this condition.
+            LOG_WARN(
+                ("Could not move old service file out of the way from:"
+                 " \"%ls\" to \"%ls\". Service will not be upgraded.  (%lu)",
+                 serviceConfig.lpBinaryPathName, oldServiceBinaryTempPath,
+                 GetLastError()));
+            result = FALSE;
+          }
+          delete[] oldServiceBinaryTempPath;
+        } else {
+          // It is best to leave the old service binary in this condition.
+          LOG_WARN(
+              ("Service binary path was less than 3, service will"
+               " not be updated.  This should never happen."));
+          result = FALSE;
+        }
+      } else {
+        WCHAR versionStr[128] = {L'\0'};
+        swprintf(versionStr, 128, L"%d.%d.%d.%d", newA, newB, newC, newD);
+        if (!UpdateUninstallerVersionString(versionStr)) {
+          LOG(("The uninstaller version string could not be updated."));
+        }
+        LOG(("The new service binary was copied in."));
+      }
+
+      // We made a copy of ourselves to the existing location.
+      // The tmp file (the process of which we are executing right now) will be
+      // left over.  Attempt to delete the file on the next reboot.
+      if (MoveFileExW(newServiceBinaryPath, nullptr,
+                      MOVEFILE_DELAY_UNTIL_REBOOT)) {
+        LOG(("Deleting the old file path on the next reboot: %ls.",
+             newServiceBinaryPath));
+      } else {
+        LOG_WARN(("Call to delete the old file path failed: %ls.",
+                  newServiceBinaryPath));
+      }
+
+      return result;
+    }
+
+    // We don't need to copy ourselves to the existing location.
+    // The tmp file (the process of which we are executing right now) will be
+    // left over.  Attempt to delete the file on the next reboot.
+    MoveFileExW(newServiceBinaryPath, nullptr, MOVEFILE_DELAY_UNTIL_REBOOT);
+
+    // nothing to do, we already have a newer service installed
+    return TRUE;
+  }
+
+  // If the service does not exist and we are upgrading, don't install it.
+  if (UpgradeSvc == action) {
+    // The service does not exist and we are upgrading, so don't install it
+    return TRUE;
+  }
+
+  // Quote the path only if it contains spaces.
+  PathQuoteSpacesW(newServiceBinaryPath);
+  // The service does not already exist so create the service as on demand
+  schService.own(CreateServiceW(
+      schSCManager, SVC_NAME, SVC_DISPLAY_NAME, SERVICE_ALL_ACCESS,
+      SERVICE_WIN32_OWN_PROCESS, SERVICE_DEMAND_START, SERVICE_ERROR_NORMAL,
+      newServiceBinaryPath, nullptr, nullptr, nullptr, nullptr, nullptr));
+  if (!schService) {
+    LOG_WARN(
+        ("Could not create Windows service. "
+         "This error should never happen since a service install "
+         "should only be called when elevated.  (%lu)",
+         GetLastError()));
+    return FALSE;
+  }
+
+  if (!SetUserAccessServiceDACL(schService)) {
+    LOG_WARN(
+        ("Could not set security ACE on service handle, the service will not "
+         "be able to be started from unelevated processes. "
+         "This error should never happen.  (%lu)",
+         GetLastError()));
+  }
+
+  UpdateServiceDescription(schService);
+
+  return TRUE;
+}
+
+/**
+ * Stops the Maintenance service.
+ *
+ * @return TRUE if successful.
+ */
+BOOL StopService() {
+  // Get a handle to the local computer SCM database with full access rights.
+  nsAutoServiceHandle schSCManager(
+      OpenSCManager(nullptr, nullptr, SC_MANAGER_ALL_ACCESS));
+  if (!schSCManager) {
+    LOG_WARN(("Could not open service manager.  (%lu)", GetLastError()));
+    return FALSE;
+  }
+
+  // Open the service
+  nsAutoServiceHandle schService(
+      OpenServiceW(schSCManager, SVC_NAME, SERVICE_ALL_ACCESS));
+  if (!schService) {
+    LOG_WARN(("Could not open service.  (%lu)", GetLastError()));
+    return FALSE;
+  }
+
+  LOG(("Sending stop request..."));
+  SERVICE_STATUS status;
+  SetLastError(ERROR_SUCCESS);
+  if (!ControlService(schService, SERVICE_CONTROL_STOP, &status) &&
+      GetLastError() != ERROR_SERVICE_NOT_ACTIVE) {
+    LOG_WARN(("Error sending stop request.  (%lu)", GetLastError()));
+  }
+
+  schSCManager.reset();
+  schService.reset();
+
+  LOG(("Waiting for service stop..."));
+  DWORD lastState = WaitForServiceStop(SVC_NAME, 30);
+
+  // The service can be in a stopped state but the exe still in use
+  // so make sure the process is really gone before proceeding
+  WaitForProcessExit(L"maintenanceservice.exe", 30);
+  LOG(("Done waiting for service stop, last service state: %lu", lastState));
+
+  return lastState == SERVICE_STOPPED;
+}
+
+/**
+ * Uninstalls the Maintenance service.
+ *
+ * @return TRUE if successful.
+ */
+BOOL SvcUninstall() {
+  // Get a handle to the local computer SCM database with full access rights.
+  nsAutoServiceHandle schSCManager(
+      OpenSCManager(nullptr, nullptr, SC_MANAGER_ALL_ACCESS));
+  if (!schSCManager) {
+    LOG_WARN(("Could not open service manager.  (%lu)", GetLastError()));
+    return FALSE;
+  }
+
+  // Open the service
+  nsAutoServiceHandle schService(
+      OpenServiceW(schSCManager, SVC_NAME, SERVICE_ALL_ACCESS));
+  if (!schService) {
+    LOG_WARN(("Could not open service.  (%lu)", GetLastError()));
+    return FALSE;
+  }
+
+  // Stop the service so it deletes faster and so the uninstaller
+  // can actually delete its EXE.
+  DWORD totalWaitTime = 0;
+  SERVICE_STATUS status;
+  static const int maxWaitTime = 1000 * 60;  // Never wait more than a minute
+  if (ControlService(schService, SERVICE_CONTROL_STOP, &status)) {
+    do {
+      Sleep(status.dwWaitHint);
+      totalWaitTime += (status.dwWaitHint + 10);
+      if (status.dwCurrentState == SERVICE_STOPPED) {
+        break;
+      } else if (totalWaitTime > maxWaitTime) {
+        break;
+      }
+    } while (QueryServiceStatus(schService, &status));
+  }
+
+  // Delete the service or mark it for deletion
+  BOOL deleted = DeleteService(schService);
+  if (!deleted) {
+    deleted = (GetLastError() == ERROR_SERVICE_MARKED_FOR_DELETE);
+  }
+
+  return deleted;
+}
+
+/**
+ * Sets the access control list for user access for the specified service.
+ *
+ * @param  hService The service to set the access control list on
+ * @return TRUE if successful
+ */
+BOOL SetUserAccessServiceDACL(SC_HANDLE hService) {
+  PACL pNewAcl = nullptr;
+  PSECURITY_DESCRIPTOR psd = nullptr;
+  DWORD lastError = SetUserAccessServiceDACL(hService, pNewAcl, psd);
+  if (pNewAcl) {
+    LocalFree((HLOCAL)pNewAcl);
+  }
+  if (psd) {
+    LocalFree((LPVOID)psd);
+  }
+  return ERROR_SUCCESS == lastError;
+}
+
+/**
+ * Sets the access control list for user access for the specified service.
+ *
+ * @param  hService  The service to set the access control list on
+ * @param  pNewAcl   The out param ACL which should be freed by caller
+ * @param  psd       out param security descriptor, should be freed by caller
+ * @return ERROR_SUCCESS if successful
+ */
+DWORD
+SetUserAccessServiceDACL(SC_HANDLE hService, PACL& pNewAcl,
+                         PSECURITY_DESCRIPTOR psd) {
+  // Get the current security descriptor needed size
+  DWORD needed = 0;
+  if (!QueryServiceObjectSecurity(hService, DACL_SECURITY_INFORMATION, &psd, 0,
+                                  &needed)) {
+    if (GetLastError() != ERROR_INSUFFICIENT_BUFFER) {
+      LOG_WARN(("Could not query service object security size.  (%lu)",
+                GetLastError()));
+      return GetLastError();
+    }
+
+    DWORD size = needed;
+    psd = (PSECURITY_DESCRIPTOR)LocalAlloc(LPTR, size);
+    if (!psd) {
+      LOG_WARN(
+          ("Could not allocate security descriptor.  (%lu)", GetLastError()));
+      return ERROR_INSUFFICIENT_BUFFER;
+    }
+
+    // Get the actual security descriptor now
+    if (!QueryServiceObjectSecurity(hService, DACL_SECURITY_INFORMATION, psd,
+                                    size, &needed)) {
+      LOG_WARN(
+          ("Could not allocate security descriptor.  (%lu)", GetLastError()));
+      return GetLastError();
+    }
+  }
+
+  // Get the current DACL from the security descriptor.
+  PACL pacl = nullptr;
+  BOOL bDaclPresent = FALSE;
+  BOOL bDaclDefaulted = FALSE;
+  if (!GetSecurityDescriptorDacl(psd, &bDaclPresent, &pacl, &bDaclDefaulted)) {
+    LOG_WARN(("Could not obtain DACL.  (%lu)", GetLastError()));
+    return GetLastError();
+  }
+
+  PSID sidBuiltinUsers;
+  DWORD SIDSize = SECURITY_MAX_SID_SIZE;
+  sidBuiltinUsers = LocalAlloc(LMEM_FIXED, SIDSize);
+  if (!sidBuiltinUsers) {
+    LOG_WARN(("Could not allocate SID memory.  (%lu)", GetLastError()));
+    return GetLastError();
+  }
+  UniqueSidPtr uniqueSidBuiltinUsers(sidBuiltinUsers);
+
+  if (!CreateWellKnownSid(WinBuiltinUsersSid, nullptr, sidBuiltinUsers,
+                          &SIDSize)) {
+    DWORD lastError = GetLastError();
+    LOG_WARN(("Could not create BI\\Users SID.  (%lu)", lastError));
+    return lastError;
+  }
+
+  PSID sidInteractive;
+  SIDSize = SECURITY_MAX_SID_SIZE;
+  sidInteractive = LocalAlloc(LMEM_FIXED, SIDSize);
+  if (!sidInteractive) {
+    LOG_WARN(("Could not allocate SID memory.  (%lu)", GetLastError()));
+    return GetLastError();
+  }
+  UniqueSidPtr uniqueSidInteractive(sidInteractive);
+
+  if (!CreateWellKnownSid(WinInteractiveSid, nullptr, sidInteractive,
+                          &SIDSize)) {
+    DWORD lastError = GetLastError();
+    LOG_WARN(("Could not create Interactive SID.  (%lu)", lastError));
+    return lastError;
+  }
+
+  const size_t eaCount = 2;
+  EXPLICIT_ACCESS ea[eaCount];
+  ZeroMemory(ea, sizeof(ea));
+  ea[0].grfAccessMode = REVOKE_ACCESS;
+  ea[0].Trustee.TrusteeForm = TRUSTEE_IS_SID;
+  ea[0].Trustee.TrusteeType = TRUSTEE_IS_GROUP;
+  ea[0].Trustee.ptstrName = static_cast<LPWSTR>(sidBuiltinUsers);
+  ea[1].grfAccessPermissions = SERVICE_START | SERVICE_STOP | GENERIC_READ;
+  ea[1].grfAccessMode = SET_ACCESS;
+  ea[1].grfInheritance = NO_INHERITANCE;
+  ea[1].Trustee.TrusteeForm = TRUSTEE_IS_SID;
+  ea[1].Trustee.TrusteeType = TRUSTEE_IS_GROUP;
+  ea[1].Trustee.ptstrName = static_cast<LPWSTR>(sidInteractive);
+
+  DWORD lastError = SetEntriesInAclW(eaCount, ea, pacl, &pNewAcl);
+  if (ERROR_SUCCESS != lastError) {
+    LOG_WARN(("Could not set entries in ACL.  (%lu)", lastError));
+    return lastError;
+  }
+
+  // Initialize a new security descriptor.
+  SECURITY_DESCRIPTOR sd;
+  if (!InitializeSecurityDescriptor(&sd, SECURITY_DESCRIPTOR_REVISION)) {
+    LOG_WARN(
+        ("Could not initialize security descriptor.  (%lu)", GetLastError()));
+    return GetLastError();
+  }
+
+  // Set the new DACL in the security descriptor.
+  if (!SetSecurityDescriptorDacl(&sd, TRUE, pNewAcl, FALSE)) {
+    LOG_WARN(
+        ("Could not set security descriptor DACL.  (%lu)", GetLastError()));
+    return GetLastError();
+  }
+
+  // Set the new security descriptor for the service object.
+  if (!SetServiceObjectSecurity(hService, DACL_SECURITY_INFORMATION, &sd)) {
+    LOG_WARN(("Could not set object security.  (%lu)", GetLastError()));
+    return GetLastError();
+  }
+
+  // Woohoo, raise the roof
+  LOG(("User access was set successfully on the service."));
+  return ERROR_SUCCESS;
+}
diff --git a/toolkit/components/maintenanceservice/serviceinstall.h b/toolkit/components/maintenanceservice/serviceinstall.h
new file mode 100644
index 0000000000..735bebd67f
--- /dev/null
+++ b/toolkit/components/maintenanceservice/serviceinstall.h
@@ -0,0 +1,19 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "readstrings.h"
+
+#define SVC_DISPLAY_NAME L"Mozilla Maintenance Service"
+
+enum SvcInstallAction { UpgradeSvc, InstallSvc, ForceInstallSvc };
+BOOL SvcInstall(SvcInstallAction action);
+BOOL SvcUninstall();
+BOOL StopService();
+BOOL SetUserAccessServiceDACL(SC_HANDLE hService);
+DWORD SetUserAccessServiceDACL(SC_HANDLE hService, PACL& pNewAcl,
+                               PSECURITY_DESCRIPTOR psd);
+
+struct MaintenanceServiceStringTable {
+  mozilla::UniquePtr<char[]> serviceDescription;
+};
diff --git a/toolkit/components/maintenanceservice/tests/gtest/ServiceStartInteractiveOnly.cpp b/toolkit/components/maintenanceservice/tests/gtest/ServiceStartInteractiveOnly.cpp
new file mode 100644
index 0000000000..beff8e8e47
--- /dev/null
+++ b/toolkit/components/maintenanceservice/tests/gtest/ServiceStartInteractiveOnly.cpp
@@ -0,0 +1,52 @@
+#include "gtest/gtest.h"
+
+#include <stdio.h>
+#include <windows.h>
+#include <sddl.h>
+
+#include "nsWindowsHelpers.h"
+
+TEST(MaintenanceServiceTest, ServiceStartInteractiveOnly)
+{
+  // First, make a restricted token that excludes the Interactive group.
+  SID_AND_ATTRIBUTES sid;
+  DWORD SIDSize = SECURITY_MAX_SID_SIZE;
+  sid.Sid = LocalAlloc(LMEM_FIXED, SIDSize);
+  // Automatically free the SID when we are done with it.
+  UniqueSidPtr uniqueSid(sid.Sid);
+  ASSERT_TRUE(sid.Sid);
+
+  BOOL success =
+      CreateWellKnownSid(WinInteractiveSid, nullptr, sid.Sid, &SIDSize);
+  ASSERT_TRUE(success);
+
+  HANDLE primaryToken;
+  success =
+      OpenProcessToken(GetCurrentProcess(), TOKEN_ALL_ACCESS, &primaryToken);
+  // Automatically close the token when we are done with it.
+  nsAutoHandle uniquePrimaryToken(primaryToken);
+  ASSERT_TRUE(success);
+
+  HANDLE restrictedToken;
+  success = CreateRestrictedToken(primaryToken, 0, 1, &sid, 0, nullptr, 0,
+                                  nullptr, &restrictedToken);
+  // Automatically close the token when we are done with it.
+  nsAutoHandle uniqueRestrictedToken(restrictedToken);
+  ASSERT_TRUE(success);
+
+  success = ImpersonateLoggedOnUser(restrictedToken);
+  ASSERT_TRUE(success);
+
+  SC_HANDLE scmHandle =
+      OpenSCManagerW(L"127.0.0.1", nullptr, SC_MANAGER_CONNECT);
+  // Automatically close the SCM when we are done with it.
+  nsAutoServiceHandle uniqueScmHandle(scmHandle);
+  ASSERT_TRUE(scmHandle);
+
+  SC_HANDLE serviceHandle =
+      OpenServiceW(scmHandle, L"MozillaMaintenance", SERVICE_START);
+  // Automatically close the SCM when we are done with it.
+  nsAutoServiceHandle uniqueServiceHandle(serviceHandle);
+  ASSERT_FALSE(serviceHandle);
+  ASSERT_EQ(GetLastError(), static_cast<DWORD>(ERROR_ACCESS_DENIED));
+}
diff --git a/toolkit/components/maintenanceservice/tests/gtest/moz.build b/toolkit/components/maintenanceservice/tests/gtest/moz.build
new file mode 100644
index 0000000000..201f67a69d
--- /dev/null
+++ b/toolkit/components/maintenanceservice/tests/gtest/moz.build
@@ -0,0 +1,20 @@
+# -*- Mode: python; c-basic-offset: 4; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, you can obtain one at https://mozilla.org/MPL/2.0/.
+
+Library("MaintenanceServiceTest")
+
+UNIFIED_SOURCES += [
+    "ServiceStartInteractiveOnly.cpp",
+]
+
+DisableStlWrapping()
+
+OS_LIBS += [
+    "advapi32",
+    "kernel32",
+]
+
+FINAL_LIBRARY = "xul-gtest"
diff --git a/toolkit/components/maintenanceservice/workmonitor.cpp b/toolkit/components/maintenanceservice/workmonitor.cpp
new file mode 100644
index 0000000000..96a098d547
--- /dev/null
+++ b/toolkit/components/maintenanceservice/workmonitor.cpp
@@ -0,0 +1,812 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <shlobj.h>
+#include <shlwapi.h>
+#include <wtsapi32.h>
+#include <userenv.h>
+#include <shellapi.h>
+
+#ifndef __MINGW32__
+#  pragma comment(lib, "wtsapi32.lib")
+#  pragma comment(lib, "userenv.lib")
+#  pragma comment(lib, "shlwapi.lib")
+#  pragma comment(lib, "ole32.lib")
+#  pragma comment(lib, "rpcrt4.lib")
+#endif
+
+#include "mozilla/CmdLineAndEnvUtils.h"
+#include "nsWindowsHelpers.h"
+#include "mozilla/UniquePtr.h"
+
+using mozilla::UniquePtr;
+
+#include "workmonitor.h"
+#include "serviceinstall.h"
+#include "servicebase.h"
+#include "registrycertificates.h"
+#include "uachelper.h"
+#include "updatehelper.h"
+#include "pathhash.h"
+#include "updatererrors.h"
+#include "commonupdatedir.h"
+
+// Wait 15 minutes for an update operation to run at most.
+// Updates usually take less than a minute so this seems like a
+// significantly large and safe amount of time to wait.
+static const int TIME_TO_WAIT_ON_UPDATER = 15 * 60 * 1000;
+BOOL PathGetSiblingFilePath(LPWSTR destinationBuffer, LPCWSTR siblingFilePath,
+                            LPCWSTR newFileName);
+BOOL DoesFallbackKeyExist();
+
+/*
+ * Reads the secure update status file and sets isApplying to true if the status
+ * is set to applying.
+ *
+ * @param  patchDirPath
+ *         The update patch directory path
+ * @param  isApplying Out parameter for specifying if the status
+ *         is set to applying or not.
+ * @return TRUE if the information was filled.
+ */
+static BOOL IsStatusApplying(LPCWSTR patchDirPath, BOOL& isApplying) {
+  isApplying = FALSE;
+  WCHAR statusFilePath[MAX_PATH + 1] = {L'\0'};
+  if (!GetSecureOutputFilePath(patchDirPath, L".status", statusFilePath)) {
+    LOG_WARN(("Could not get path for the secure update status file"));
+    return FALSE;
+  }
+
+  nsAutoHandle statusFile(
+      CreateFileW(statusFilePath, GENERIC_READ,
+                  FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
+                  nullptr, OPEN_EXISTING, 0, nullptr));
+
+  if (INVALID_HANDLE_VALUE == statusFile) {
+    LOG_WARN(("Could not open update.status file"));
+    return FALSE;
+  }
+
+  char buf[32] = {0};
+  DWORD read;
+  if (!ReadFile(statusFile, buf, sizeof(buf), &read, nullptr)) {
+    LOG_WARN(("Could not read from update.status file"));
+    return FALSE;
+  }
+
+  const char kApplying[] = "applying";
+  isApplying = strncmp(buf, kApplying, sizeof(kApplying) - 1) == 0;
+  return TRUE;
+}
+
+/**
+ * Determines whether we're staging an update.
+ *
+ * @param  argc    The argc value normally sent to updater.exe
+ * @param  argv    The argv value normally sent to updater.exe
+ * @return boolean True if we're staging an update
+ */
+static bool IsUpdateBeingStaged(int argc, LPWSTR* argv) {
+  // PID will be set to -1 if we're supposed to stage an update.
+  return (argc == 4 && !wcscmp(argv[3], L"-1")) ||
+         (argc == 5 && !wcscmp(argv[4], L"-1"));
+}
+
+/**
+ * Determines whether the param only contains digits.
+ *
+ * @param str     The string to check
+ * @param boolean True if the param only contains digits
+ */
+static bool IsDigits(WCHAR* str) {
+  while (*str) {
+    if (!iswdigit(*str++)) {
+      return FALSE;
+    }
+  }
+  return TRUE;
+}
+
+/**
+ * Determines whether the command line contains just the directory to apply the
+ * update to (old command line) or if it contains the installation directory and
+ * the directory to apply the update to.
+ *
+ * @param argc    The argc value normally sent to updater.exe
+ * @param argv    The argv value normally sent to updater.exe
+ * @param boolean True if the command line contains just the directory to apply
+ *                the update to
+ */
+static bool IsOldCommandline(int argc, LPWSTR* argv) {
+  return (argc == 4 && !wcscmp(argv[3], L"-1")) ||
+         (argc >= 4 && (wcsstr(argv[3], L"/replace") || IsDigits(argv[3])));
+}
+
+/**
+ * Gets the installation directory from the arguments passed to updater.exe.
+ *
+ * @param argcTmp    The argc value normally sent to updater.exe
+ * @param argvTmp    The argv value normally sent to updater.exe
+ * @param aResultDir Buffer to hold the installation directory.
+ */
+static BOOL GetInstallationDir(int argcTmp, LPWSTR* argvTmp,
+                               WCHAR aResultDir[MAX_PATH + 1]) {
+  int index = 3;
+  if (IsOldCommandline(argcTmp, argvTmp)) {
+    index = 2;
+  }
+
+  if (argcTmp < index) {
+    return FALSE;
+  }
+
+  wcsncpy(aResultDir, argvTmp[2], MAX_PATH);
+  WCHAR* backSlash = wcsrchr(aResultDir, L'\\');
+  // Make sure that the path does not include trailing backslashes
+  if (backSlash && (backSlash[1] == L'\0')) {
+    *backSlash = L'\0';
+  }
+
+  // The new command line's argv[2] is always the installation directory.
+  if (index == 2) {
+    bool backgroundUpdate = IsUpdateBeingStaged(argcTmp, argvTmp);
+    bool replaceRequest = (argcTmp >= 4 && wcsstr(argvTmp[3], L"/replace"));
+    if (backgroundUpdate || replaceRequest) {
+      return PathRemoveFileSpecW(aResultDir);
+    }
+  }
+  return TRUE;
+}
+
+/**
+ * Runs an update process as the service using the SYSTEM account.
+ *
+ * @param  argc           The number of arguments in argv
+ * @param  argv           The arguments normally passed to updater.exe
+ *                        argv[0] must be the path to updater.exe
+ * @param  processStarted Set to TRUE if the process was started.
+ * @return TRUE if the update process was run had a return code of 0.
+ */
+BOOL StartUpdateProcess(int argc, LPWSTR* argv, LPCWSTR installDir,
+                        BOOL& processStarted) {
+  processStarted = FALSE;
+
+  LOG(("Starting update process as the service in session 0."));
+  STARTUPINFOW si;
+  PROCESS_INFORMATION pi;
+
+  ZeroMemory(&si, sizeof(si));
+  ZeroMemory(&pi, sizeof(pi));
+  si.cb = sizeof(si);
+  si.lpDesktop = const_cast<LPWSTR>(L"winsta0\\Default");  // -Wwritable-strings
+
+  // The updater command line is of the form:
+  // updater.exe update-dir apply [wait-pid [callback-dir callback-path args]]
+  auto cmdLine = mozilla::MakeCommandLine(argc, argv);
+
+  int index = 3;
+  if (IsOldCommandline(argc, argv)) {
+    index = 2;
+  }
+
+  // If we're about to start the update process from session 0,
+  // then we should not show a GUI.  This only really needs to be done
+  // on Vista and higher, but it's better to keep everything consistent
+  // across all OS if it's of no harm.
+  if (argc >= index) {
+    // Setting the desktop to blank will ensure no GUI is displayed
+    si.lpDesktop = const_cast<LPWSTR>(L"");  // -Wwritable-strings
+    si.dwFlags |= STARTF_USESHOWWINDOW;
+    si.wShowWindow = SW_HIDE;
+  }
+
+  // Add an env var for MOZ_USING_SERVICE so the updater.exe can
+  // do anything special that it needs to do for service updates.
+  // Search in updater.cpp for more info on MOZ_USING_SERVICE.
+  putenv(const_cast<char*>("MOZ_USING_SERVICE=1"));
+
+  LOG(("Starting service with cmdline: %ls", cmdLine.get()));
+  processStarted =
+      CreateProcessW(argv[0], cmdLine.get(), nullptr, nullptr, FALSE,
+                     CREATE_DEFAULT_ERROR_MODE, nullptr, nullptr, &si, &pi);
+
+  BOOL updateWasSuccessful = FALSE;
+  if (processStarted) {
+    BOOL processTerminated = FALSE;
+    BOOL noProcessExitCode = FALSE;
+    // Wait for the updater process to finish
+    LOG(("Process was started... waiting on result."));
+    DWORD waitRes = WaitForSingleObject(pi.hProcess, TIME_TO_WAIT_ON_UPDATER);
+    if (WAIT_TIMEOUT == waitRes) {
+      // We waited a long period of time for updater.exe and it never finished
+      // so kill it.
+      TerminateProcess(pi.hProcess, 1);
+      processTerminated = TRUE;
+    } else {
+      // Check the return code of updater.exe to make sure we get 0
+      DWORD returnCode;
+      if (GetExitCodeProcess(pi.hProcess, &returnCode)) {
+        LOG(("Process finished with return code %lu.", returnCode));
+        // updater returns 0 if successful.
+        updateWasSuccessful = (returnCode == 0);
+      } else {
+        LOG_WARN(("Process finished but could not obtain return code."));
+        noProcessExitCode = TRUE;
+      }
+    }
+    CloseHandle(pi.hProcess);
+    CloseHandle(pi.hThread);
+
+    // Check just in case updater.exe didn't change the status from
+    // applying.  If this is the case we report an error.
+    BOOL isApplying = FALSE;
+    if (IsStatusApplying(argv[1], isApplying) && isApplying) {
+      if (updateWasSuccessful) {
+        LOG(
+            ("update.status is still applying even though update was "
+             "successful."));
+        if (!WriteStatusFailure(argv[1], SERVICE_STILL_APPLYING_ON_SUCCESS)) {
+          LOG_WARN(
+              ("Could not write update.status still applying on "
+               "success error."));
+        }
+        // Since we still had applying we know updater.exe didn't do its
+        // job correctly.
+        updateWasSuccessful = FALSE;
+      } else {
+        LOG_WARN(
+            ("update.status is still applying and update was not successful."));
+        int failcode = SERVICE_STILL_APPLYING_ON_FAILURE;
+        if (noProcessExitCode) {
+          failcode = SERVICE_STILL_APPLYING_NO_EXIT_CODE;
+        } else if (processTerminated) {
+          failcode = SERVICE_STILL_APPLYING_TERMINATED;
+        }
+        if (!WriteStatusFailure(argv[1], failcode)) {
+          LOG_WARN(
+              ("Could not write update.status still applying on "
+               "failure error."));
+        }
+      }
+    }
+  } else {
+    DWORD lastError = GetLastError();
+    LOG_WARN(
+        ("Could not create process as current user, "
+         "updaterPath: %ls; cmdLine: %ls.  (%lu)",
+         argv[0], cmdLine.get(), lastError));
+  }
+
+  // Empty value on putenv is how you remove an env variable in Windows
+  putenv(const_cast<char*>("MOZ_USING_SERVICE="));
+
+  return updateWasSuccessful;
+}
+
+/**
+ * Validates a file as an official updater.
+ *
+ * @param updater     Path to the updater to validate
+ * @param installDir  Path to the application installation
+ *                    being updated
+ * @param updateDir   Update applyTo direcotry,
+ *                    where logs will be written
+ *
+ * @return true if updater is the path to a valid updater
+ */
+static bool UpdaterIsValid(LPWSTR updater, LPWSTR installDir,
+                           LPWSTR updateDir) {
+  // Make sure the path to the updater to use for the update is local.
+  // We do this check to make sure that file locking is available for
+  // race condition security checks.
+  BOOL isLocal = FALSE;
+  if (!IsLocalFile(updater, isLocal) || !isLocal) {
+    LOG_WARN(("Filesystem in path %ls is not supported (%lu)", updater,
+              GetLastError()));
+    if (!WriteStatusFailure(updateDir, SERVICE_UPDATER_NOT_FIXED_DRIVE)) {
+      LOG_WARN(("Could not write update.status service update failure.  (%lu)",
+                GetLastError()));
+    }
+    return false;
+  }
+
+  nsAutoHandle noWriteLock(CreateFileW(updater, GENERIC_READ, FILE_SHARE_READ,
+                                       nullptr, OPEN_EXISTING, 0, nullptr));
+  if (INVALID_HANDLE_VALUE == noWriteLock) {
+    LOG_WARN(("Could not set no write sharing access on file.  (%lu)",
+              GetLastError()));
+    if (!WriteStatusFailure(updateDir, SERVICE_COULD_NOT_LOCK_UPDATER)) {
+      LOG_WARN(("Could not write update.status service update failure.  (%lu)",
+                GetLastError()));
+    }
+    return false;
+  }
+
+  // Verify that the updater.exe that we are executing is the same
+  // as the one in the installation directory which we are updating.
+  // The installation dir that we are installing to is installDir.
+  WCHAR installDirUpdater[MAX_PATH + 1] = {L'\0'};
+  wcsncpy(installDirUpdater, installDir, MAX_PATH);
+  if (!PathAppendSafe(installDirUpdater, L"updater.exe")) {
+    LOG_WARN(("Install directory updater could not be determined."));
+    return false;
+  }
+
+  BOOL updaterIsCorrect;
+  if (!VerifySameFiles(updater, installDirUpdater, updaterIsCorrect)) {
+    LOG_WARN(
+        ("Error checking if the updaters are the same.\n"
+         "Path 1: %ls\nPath 2: %ls",
+         updater, installDirUpdater));
+    return false;
+  }
+
+  if (!updaterIsCorrect) {
+    LOG_WARN(
+        ("The updaters do not match, updater will not run.\n"
+         "Path 1: %ls\nPath 2: %ls",
+         updater, installDirUpdater));
+    if (!WriteStatusFailure(updateDir, SERVICE_UPDATER_COMPARE_ERROR)) {
+      LOG_WARN(("Could not write update.status updater compare failure."));
+    }
+    return false;
+  }
+
+  LOG(
+      ("updater.exe was compared successfully to the installation directory"
+       " updater.exe."));
+
+  // Check to make sure the updater.exe module has the unique updater identity.
+  // This is a security measure to make sure that the signed executable that
+  // we will run is actually an updater.
+  bool result = true;
+  HMODULE updaterModule =
+      LoadLibraryEx(updater, nullptr, LOAD_LIBRARY_AS_DATAFILE);
+  if (!updaterModule) {
+    LOG_WARN(("updater.exe module could not be loaded. (%lu)", GetLastError()));
+    result = false;
+  } else {
+    char updaterIdentity[64];
+    if (!LoadStringA(updaterModule, IDS_UPDATER_IDENTITY, updaterIdentity,
+                     sizeof(updaterIdentity))) {
+      LOG_WARN(
+          ("The updater.exe application does not contain the Mozilla"
+           " updater identity."));
+      result = false;
+    }
+
+    if (strcmp(updaterIdentity, UPDATER_IDENTITY_STRING)) {
+      LOG_WARN(("The updater.exe identity string is not valid."));
+      result = false;
+    }
+    FreeLibrary(updaterModule);
+  }
+
+  if (result) {
+    LOG(
+        ("The updater.exe application contains the Mozilla"
+         " updater identity."));
+  } else {
+    if (!WriteStatusFailure(updateDir, SERVICE_UPDATER_IDENTITY_ERROR)) {
+      LOG_WARN(("Could not write update.status no updater identity."));
+    }
+    return false;
+  }
+
+#ifndef DISABLE_UPDATER_AUTHENTICODE_CHECK
+  return DoesBinaryMatchAllowedCertificates(installDir, updater);
+#else
+  return true;
+#endif
+}
+
+/**
+ * Processes a software update command
+ *
+ * @param  argc           The number of arguments in argv
+ * @param  argv           The arguments normally passed to updater.exe
+ *                        argv[0] must be the path to updater.exe
+ *
+ * @return TRUE if the update was successful.
+ */
+BOOL ProcessSoftwareUpdateCommand(DWORD argc, LPWSTR* argv) {
+  BOOL result = TRUE;
+  if (argc < 3) {
+    LOG_WARN(
+        ("Not enough command line parameters specified. "
+         "Updating update.status."));
+
+    // We can only update update.status if argv[1] exists.  argv[1] is
+    // the directory where the update.status file exists.
+    if (argc < 2 ||
+        !WriteStatusFailure(argv[1], SERVICE_NOT_ENOUGH_COMMAND_LINE_ARGS)) {
+      LOG_WARN(("Could not write update.status service update failure.  (%lu)",
+                GetLastError()));
+    }
+    return FALSE;
+  }
+
+  WCHAR installDir[MAX_PATH + 1] = {L'\0'};
+  if (!GetInstallationDir(argc, argv, installDir)) {
+    LOG_WARN(("Could not get the installation directory"));
+    if (!WriteStatusFailure(argv[1], SERVICE_INSTALLDIR_ERROR)) {
+      LOG_WARN(
+          ("Could not write update.status for GetInstallationDir failure."));
+    }
+    return FALSE;
+  }
+
+  if (UpdaterIsValid(argv[0], installDir, argv[1])) {
+    BOOL updateProcessWasStarted = FALSE;
+    if (StartUpdateProcess(argc, argv, installDir, updateProcessWasStarted)) {
+      LOG(("updater.exe was launched and run successfully!"));
+      LogFlush();
+
+      // Don't attempt to update the service when the update is being staged.
+      if (!IsUpdateBeingStaged(argc, argv)) {
+        // We might not execute code after StartServiceUpdate because
+        // the service installer will stop the service if it is running.
+        StartServiceUpdate(installDir);
+      }
+    } else {
+      result = FALSE;
+      LOG_WARN(("Error running update process. Updating update.status  (%lu)",
+                GetLastError()));
+      LogFlush();
+
+      // If the update process was started, then updater.exe is responsible for
+      // setting the failure code.  If it could not be started then we do the
+      // work.  We set an error instead of directly setting status pending
+      // so that the app.update.service.errors pref can be updated when
+      // the callback app restarts.
+      if (!updateProcessWasStarted) {
+        if (!WriteStatusFailure(argv[1],
+                                SERVICE_UPDATER_COULD_NOT_BE_STARTED)) {
+          LOG_WARN(
+              ("Could not write update.status service update failure.  (%lu)",
+               GetLastError()));
+        }
+      }
+    }
+  } else {
+    result = FALSE;
+    LOG_WARN(
+        ("Could not start process due to certificate check error on "
+         "updater.exe. Updating update.status.  (%lu)",
+         GetLastError()));
+
+    // When there is a certificate check error on the updater.exe application,
+    // we want to write out the error.
+    if (!WriteStatusFailure(argv[1], SERVICE_UPDATER_SIGN_ERROR)) {
+      LOG_WARN(("Could not write pending state to update.status.  (%lu)",
+                GetLastError()));
+    }
+  }
+
+  return result;
+}
+
+/**
+ * Obtains the updater path alongside a subdir of the service binary.
+ * The purpose of this function is to return a path that is likely high
+ * integrity and therefore more safe to execute code from.
+ *
+ * @param serviceUpdaterPath Out parameter for the path where the updater
+ *                           should be copied to.
+ * @return TRUE if a file path was obtained.
+ */
+BOOL GetSecureUpdaterPath(WCHAR serviceUpdaterPath[MAX_PATH + 1]) {
+  if (!GetModuleFileNameW(nullptr, serviceUpdaterPath, MAX_PATH)) {
+    LOG_WARN(
+        ("Could not obtain module filename when attempting to "
+         "use a secure updater path.  (%lu)",
+         GetLastError()));
+    return FALSE;
+  }
+
+  if (!PathRemoveFileSpecW(serviceUpdaterPath)) {
+    LOG_WARN(
+        ("Couldn't remove file spec when attempting to use a secure "
+         "updater path.  (%lu)",
+         GetLastError()));
+    return FALSE;
+  }
+
+  if (!PathAppendSafe(serviceUpdaterPath, L"update")) {
+    LOG_WARN(
+        ("Couldn't append file spec when attempting to use a secure "
+         "updater path.  (%lu)",
+         GetLastError()));
+    return FALSE;
+  }
+
+  CreateDirectoryW(serviceUpdaterPath, nullptr);
+
+  if (!PathAppendSafe(serviceUpdaterPath, L"updater.exe")) {
+    LOG_WARN(
+        ("Couldn't append file spec when attempting to use a secure "
+         "updater path.  (%lu)",
+         GetLastError()));
+    return FALSE;
+  }
+
+  return TRUE;
+}
+
+/**
+ * Deletes the passed in updater path and the associated updater.ini file.
+ *
+ * @param serviceUpdaterPath The path to delete.
+ * @return TRUE if a file was deleted.
+ */
+BOOL DeleteSecureUpdater(WCHAR serviceUpdaterPath[MAX_PATH + 1]) {
+  BOOL result = FALSE;
+  if (serviceUpdaterPath[0]) {
+    result = DeleteFileW(serviceUpdaterPath);
+    if (!result && GetLastError() != ERROR_PATH_NOT_FOUND &&
+        GetLastError() != ERROR_FILE_NOT_FOUND) {
+      LOG_WARN(("Could not delete service updater path: '%ls'.",
+                serviceUpdaterPath));
+    }
+
+    WCHAR updaterINIPath[MAX_PATH + 1] = {L'\0'};
+    if (PathGetSiblingFilePath(updaterINIPath, serviceUpdaterPath,
+                               L"updater.ini")) {
+      result = DeleteFileW(updaterINIPath);
+      if (!result && GetLastError() != ERROR_PATH_NOT_FOUND &&
+          GetLastError() != ERROR_FILE_NOT_FOUND) {
+        LOG_WARN(("Could not delete service updater INI path: '%ls'.",
+                  updaterINIPath));
+      }
+    }
+  }
+  return result;
+}
+
+/**
+ * Executes a service command.
+ *
+ * @param argc The number of arguments in argv
+ * @param argv The service command line arguments, argv[0] is automatically
+ *             included by Windows, argv[1] is unused but hardcoded to
+ *             "MozillaMaintenance", and argv[2] is the service command.
+ *
+ * @return FALSE if there was an error executing the service command.
+ */
+BOOL ExecuteServiceCommand(int argc, LPWSTR* argv) {
+  if (argc < 3) {
+    LOG_WARN(
+        ("Not enough command line arguments to execute a service command"));
+    return FALSE;
+  }
+
+  // The tests work by making sure the log has changed, so we put a
+  // unique ID in the log.
+  WCHAR uuidString[MAX_PATH + 1] = {L'\0'};
+  if (GetUUIDString(uuidString)) {
+    LOG(("Executing service command %ls, ID: %ls", argv[2], uuidString));
+  } else {
+    // The ID is only used by tests, so failure to allocate it isn't fatal.
+    LOG(("Executing service command %ls", argv[2]));
+  }
+
+  BOOL result = FALSE;
+  if (!lstrcmpi(argv[2], L"software-update")) {
+    // This check is also performed in updater.cpp and is performed here
+    // as well since the maintenance service can be called directly.
+    if (argc <= 4 || !IsValidFullPath(argv[4])) {
+      // Since the status file is written to the patch directory and the patch
+      // directory is invalid don't write the status file.
+      LOG_WARN(("The patch directory path is not valid for this application."));
+      return FALSE;
+    }
+
+    // The patch directory path must end with updates\0 to use the maintenance
+    // service.
+    size_t fullPathLen = NS_tstrlen(argv[4]);
+    size_t relPathLen = NS_tstrlen(PATCH_DIR_PATH);
+    if (relPathLen > fullPathLen) {
+      LOG_WARN(
+          ("The patch directory path length is not valid for this "
+           "application."));
+      return FALSE;
+    }
+
+    if (_wcsnicmp(argv[4] + fullPathLen - relPathLen, PATCH_DIR_PATH,
+                  relPathLen) != 0) {
+      LOG_WARN(
+          ("The patch directory path subdirectory is not valid for this "
+           "application."));
+      return FALSE;
+    }
+
+    // Remove the secure output files so it is easier to determine when new
+    // files are created in the unelevated updater.
+    RemoveSecureOutputFiles(argv[4]);
+
+    // Create a new secure ID for this update.
+    if (!WriteSecureIDFile(argv[4])) {
+      LOG_WARN(("Unable to write to secure ID file."));
+      return FALSE;
+    }
+
+    // This check is also performed in updater.cpp and is performed here
+    // as well since the maintenance service can be called directly.
+    if (argc <= 5 || !IsValidFullPath(argv[5])
+    // This build flag is used as a handy proxy to tell when we're a build made
+    // for local testing, because there isn't much other reason to set it.
+#ifndef DISABLE_UPDATER_AUTHENTICODE_CHECK
+        || !IsProgramFilesPath(argv[5])
+#endif
+    ) {
+      LOG_WARN(
+          ("The install directory path is not valid for this application."));
+      if (!WriteStatusFailure(argv[4],
+                              SERVICE_INVALID_INSTALL_DIR_PATH_ERROR)) {
+        LOG_WARN(("Could not write update.status for previous failure."));
+      }
+      return FALSE;
+    }
+
+    if (!IsOldCommandline(argc - 3, argv + 3)) {
+      // This check is also performed in updater.cpp and is performed here
+      // as well since the maintenance service can be called directly.
+      if (argc <= 6 || !IsValidFullPath(argv[6])) {
+        LOG_WARN(
+            ("The working directory path is not valid for this application."));
+        if (!WriteStatusFailure(argv[4],
+                                SERVICE_INVALID_WORKING_DIR_PATH_ERROR)) {
+          LOG_WARN(("Could not write update.status for previous failure."));
+        }
+        return FALSE;
+      }
+
+      // These checks are also performed in updater.cpp and is performed here
+      // as well since the maintenance service can be called directly.
+      if (_wcsnicmp(argv[6], argv[5], MAX_PATH) != 0) {
+        if (argc <= 7 ||
+            (wcscmp(argv[7], L"-1") != 0 && !wcsstr(argv[7], L"/replace"))) {
+          LOG_WARN(
+              ("Installation directory and working directory must be the "
+               "same for non-staged updates. Exiting."));
+          if (!WriteStatusFailure(argv[4], SERVICE_INVALID_APPLYTO_DIR_ERROR)) {
+            LOG_WARN(("Could not write update.status for previous failure."));
+          }
+          return FALSE;
+        }
+
+        NS_tchar workingDirParent[MAX_PATH];
+        NS_tsnprintf(workingDirParent,
+                     sizeof(workingDirParent) / sizeof(workingDirParent[0]),
+                     NS_T("%s"), argv[6]);
+        if (!PathRemoveFileSpecW(workingDirParent)) {
+          LOG_WARN(
+              ("Couldn't remove file spec when attempting to verify the "
+               "working directory path.  (%lu)",
+               GetLastError()));
+          if (!WriteStatusFailure(argv[4], REMOVE_FILE_SPEC_ERROR)) {
+            LOG_WARN(("Could not write update.status for previous failure."));
+          }
+          return FALSE;
+        }
+
+        if (_wcsnicmp(workingDirParent, argv[5], MAX_PATH) != 0) {
+          LOG_WARN(
+              ("The apply-to directory must be the same as or "
+               "a child of the installation directory! Exiting."));
+          if (!WriteStatusFailure(argv[4],
+                                  SERVICE_INVALID_APPLYTO_DIR_STAGED_ERROR)) {
+            LOG_WARN(("Could not write update.status for previous failure."));
+          }
+          return FALSE;
+        }
+      }
+    }
+
+    // Use the passed in command line arguments for the update, except for the
+    // path to updater.exe. We always look for updater.exe in the installation
+    // directory, then we copy that updater.exe to a the directory of the
+    // MozillaMaintenance service so that a low integrity process cannot
+    // replace the updater.exe at any point and use that for the update.
+    // It also makes DLL injection attacks harder.
+    WCHAR installDir[MAX_PATH + 1] = {L'\0'};
+    if (!GetInstallationDir(argc - 3, argv + 3, installDir)) {
+      LOG_WARN(("Could not get the installation directory"));
+      if (!WriteStatusFailure(argv[4], SERVICE_INSTALLDIR_ERROR)) {
+        LOG_WARN(("Could not write update.status for previous failure."));
+      }
+      return FALSE;
+    }
+
+    if (!DoesFallbackKeyExist()) {
+      WCHAR maintenanceServiceKey[MAX_PATH + 1];
+      if (CalculateRegistryPathFromFilePath(installDir,
+                                            maintenanceServiceKey)) {
+        LOG(("Checking for Maintenance Service registry. key: '%ls'",
+             maintenanceServiceKey));
+        HKEY baseKey = nullptr;
+        if (RegOpenKeyExW(HKEY_LOCAL_MACHINE, maintenanceServiceKey, 0,
+                          KEY_READ | KEY_WOW64_64KEY,
+                          &baseKey) != ERROR_SUCCESS) {
+          LOG_WARN(("The maintenance service registry key does not exist."));
+          if (!WriteStatusFailure(argv[4], SERVICE_INSTALL_DIR_REG_ERROR)) {
+            LOG_WARN(("Could not write update.status for previous failure."));
+          }
+          return FALSE;
+        }
+        RegCloseKey(baseKey);
+      } else {
+        if (!WriteStatusFailure(argv[4], SERVICE_CALC_REG_PATH_ERROR)) {
+          LOG_WARN(("Could not write update.status for previous failure."));
+        }
+        return FALSE;
+      }
+    }
+
+    WCHAR installDirUpdater[MAX_PATH + 1] = {L'\0'};
+    wcsncpy(installDirUpdater, installDir, MAX_PATH);
+    if (!PathAppendSafe(installDirUpdater, L"updater.exe")) {
+      LOG_WARN(("Install directory updater could not be determined."));
+      result = FALSE;
+    }
+
+    result = UpdaterIsValid(installDirUpdater, installDir, argv[4]);
+
+    WCHAR secureUpdaterPath[MAX_PATH + 1] = {L'\0'};
+    if (result) {
+      result = GetSecureUpdaterPath(secureUpdaterPath);  // Does its own logging
+    }
+    if (result) {
+      LOG(
+          ("Passed in path: '%ls' (ignored); "
+           "Install dir has: '%ls'; "
+           "Using this path for updating: '%ls'.",
+           argv[3], installDirUpdater, secureUpdaterPath));
+      DeleteSecureUpdater(secureUpdaterPath);
+      result = CopyFileW(installDirUpdater, secureUpdaterPath, FALSE);
+    }
+
+    if (!result) {
+      LOG_WARN(
+          ("Could not copy path to secure location.  (%lu)", GetLastError()));
+      if (!WriteStatusFailure(argv[4], SERVICE_COULD_NOT_COPY_UPDATER)) {
+        LOG_WARN(
+            ("Could not write update.status could not copy updater error"));
+      }
+    } else {
+      // We obtained the path and copied it successfully, update the path to
+      // use for the service update.
+      argv[3] = secureUpdaterPath;
+
+      WCHAR installDirUpdaterINIPath[MAX_PATH + 1] = {L'\0'};
+      WCHAR secureUpdaterINIPath[MAX_PATH + 1] = {L'\0'};
+      if (PathGetSiblingFilePath(secureUpdaterINIPath, secureUpdaterPath,
+                                 L"updater.ini") &&
+          PathGetSiblingFilePath(installDirUpdaterINIPath, installDirUpdater,
+                                 L"updater.ini")) {
+        // This is non fatal if it fails there is no real harm
+        if (!CopyFileW(installDirUpdaterINIPath, secureUpdaterINIPath, FALSE)) {
+          LOG_WARN(("Could not copy updater.ini from: '%ls' to '%ls'.  (%lu)",
+                    installDirUpdaterINIPath, secureUpdaterINIPath,
+                    GetLastError()));
+        }
+      }
+
+      result = ProcessSoftwareUpdateCommand(argc - 3, argv + 3);
+      DeleteSecureUpdater(secureUpdaterPath);
+    }
+
+    // We might not reach here if the service install succeeded
+    // because the service self updates itself and the service
+    // installer will stop the service.
+    LOG(("Service command %ls complete.", argv[2]));
+  } else {
+    LOG_WARN(("Service command not recognized: %ls.", argv[2]));
+    // result is already set to FALSE
+  }
+
+  LOG(("service command %ls complete with result: %ls.", argv[1],
+       (result ? L"Success" : L"Failure")));
+  return result;
+}
diff --git a/toolkit/components/maintenanceservice/workmonitor.h b/toolkit/components/maintenanceservice/workmonitor.h
new file mode 100644
index 0000000000..8fc2e51a7d
--- /dev/null
+++ b/toolkit/components/maintenanceservice/workmonitor.h
@@ -0,0 +1,5 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+BOOL ExecuteServiceCommand(int argc, LPWSTR* argv);