/* 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>

// Needed for CreateToolhelp32Snapshot
#include <tlhelp32.h>
#ifndef ONLY_SERVICE_LAUNCHING

#include <stdio.h>
#include "shlobj.h"
#include "updatehelper.h"
#include "uachelper.h"
#include "pathhash.h"
#include "mozilla/UniquePtr.h"

// Needed for PathAppendW
#include <shlwapi.h>

using mozilla::MakeUnique;
using mozilla::UniquePtr;

BOOL PathAppendSafe(LPWSTR base, LPCWSTR extra);
BOOL PathGetSiblingFilePath(LPWSTR destinationBuffer,
                            LPCWSTR siblingFilePath,
                            LPCWSTR newFileName);

/**
 * Obtains the path of a file in the same directory as the specified file.
 *
 * @param  destinationBuffer A buffer of size MAX_PATH + 1 to store the result.
 * @param  siblingFIlePath   The path of another file in the same directory
 * @param  newFileName       The filename of another file in the same directory
 * @return TRUE if successful
 */
BOOL
PathGetSiblingFilePath(LPWSTR destinationBuffer,
                       LPCWSTR siblingFilePath,
                       LPCWSTR newFileName)
{
  if (wcslen(siblingFilePath) >= MAX_PATH) {
    return FALSE;
  }

  wcsncpy(destinationBuffer, siblingFilePath, MAX_PATH);
  if (!PathRemoveFileSpecW(destinationBuffer)) {
    return FALSE;
  }

  if (wcslen(destinationBuffer) + wcslen(newFileName) >= MAX_PATH) {
    return FALSE;
  }

  return PathAppendSafe(destinationBuffer, newFileName);
}

/**
 * Starts the upgrade process for update of the service if it is
 * already installed.
 *
 * @param  installDir the installation directory where
 *         maintenanceservice_installer.exe is located.
 * @return TRUE if successful
 */
BOOL
StartServiceUpdate(LPCWSTR installDir)
{
  // Get a handle to the local computer SCM database
  SC_HANDLE manager = OpenSCManager(nullptr, nullptr,
                                    SC_MANAGER_ALL_ACCESS);
  if (!manager) {
    return FALSE;
  }

  // Open the service
  SC_HANDLE svc = OpenServiceW(manager, SVC_NAME,
                               SERVICE_ALL_ACCESS);
  if (!svc) {
    CloseServiceHandle(manager);
    return FALSE;
  }

  // If we reach here, then the service is installed, so
  // proceed with upgrading it.

  CloseServiceHandle(manager);

  // The service exists and we opened it, get the config bytes needed
  DWORD bytesNeeded;
  if (!QueryServiceConfigW(svc, nullptr, 0, &bytesNeeded) &&
      GetLastError() != ERROR_INSUFFICIENT_BUFFER) {
    CloseServiceHandle(svc);
    return FALSE;
  }

  // Get the service config information, in particular we want the binary
  // path of the service.
  UniquePtr<char[]> serviceConfigBuffer = MakeUnique<char[]>(bytesNeeded);
  if (!QueryServiceConfigW(svc,
      reinterpret_cast<QUERY_SERVICE_CONFIGW*>(serviceConfigBuffer.get()),
      bytesNeeded, &bytesNeeded)) {
    CloseServiceHandle(svc);
    return FALSE;
  }

  CloseServiceHandle(svc);

  QUERY_SERVICE_CONFIGW &serviceConfig =
    *reinterpret_cast<QUERY_SERVICE_CONFIGW*>(serviceConfigBuffer.get());

  PathUnquoteSpacesW(serviceConfig.lpBinaryPathName);

  // Obtain the temp path of the maintenance service binary
  WCHAR tmpService[MAX_PATH + 1] = { L'\0' };
  if (!PathGetSiblingFilePath(tmpService, serviceConfig.lpBinaryPathName,
                              L"maintenanceservice_tmp.exe")) {
    return FALSE;
  }

  // Get the new maintenance service path from the install dir
  WCHAR newMaintServicePath[MAX_PATH + 1] = { L'\0' };
  wcsncpy(newMaintServicePath, installDir, MAX_PATH);
  PathAppendSafe(newMaintServicePath,
                 L"maintenanceservice.exe");

  // Copy the temp file in alongside the maintenace service.
  // This is a requirement for maintenance service upgrades.
  if (!CopyFileW(newMaintServicePath, tmpService, FALSE)) {
    return FALSE;
  }

  // Start the upgrade comparison process
  STARTUPINFOW si = {0};
  si.cb = sizeof(STARTUPINFOW);
  // No particular desktop because no UI
  si.lpDesktop = L"";
  PROCESS_INFORMATION pi = {0};
  WCHAR cmdLine[64] = { '\0' };
  wcsncpy(cmdLine, L"dummyparam.exe upgrade",
          sizeof(cmdLine) / sizeof(cmdLine[0]) - 1);
  BOOL svcUpdateProcessStarted = CreateProcessW(tmpService,
                                                cmdLine,
                                                nullptr, nullptr, FALSE,
                                                0,
                                                nullptr, installDir, &si, &pi);
  if (svcUpdateProcessStarted) {
    CloseHandle(pi.hProcess);
    CloseHandle(pi.hThread);
  }
  return svcUpdateProcessStarted;
}

#endif

/**
 * Executes a maintenance service command
 *
 * @param  argc    The total number of arguments in argv
 * @param  argv    An array of null terminated strings to pass to the service,
 * @return ERROR_SUCCESS if the service command was started.
 *         Less than 16000, a windows system error code from StartServiceW
 *         More than 20000, 20000 + the last state of the service constant if
 *         the last state is something other than stopped.
 *         17001 if the SCM could not be opened
 *         17002 if the service could not be opened
*/
DWORD
StartServiceCommand(int argc, LPCWSTR* argv)
{
  DWORD lastState = WaitForServiceStop(SVC_NAME, 5);
  if (lastState != SERVICE_STOPPED) {
    return 20000 + lastState;
  }

  // Get a handle to the SCM database.
  SC_HANDLE serviceManager = OpenSCManager(nullptr, nullptr,
                                           SC_MANAGER_CONNECT |
                                           SC_MANAGER_ENUMERATE_SERVICE);
  if (!serviceManager)  {
    return 17001;
  }

  // Get a handle to the service.
  SC_HANDLE service = OpenServiceW(serviceManager,
                                   SVC_NAME,
                                   SERVICE_START);
  if (!service) {
    CloseServiceHandle(serviceManager);
    return 17002;
  }

  // Wait at most 5 seconds trying to start the service in case of errors
  // like ERROR_SERVICE_DATABASE_LOCKED or ERROR_SERVICE_REQUEST_TIMEOUT.
  const DWORD maxWaitMS = 5000;
  DWORD currentWaitMS = 0;
  DWORD lastError = ERROR_SUCCESS;
  while (currentWaitMS < maxWaitMS) {
    BOOL result = StartServiceW(service, argc, argv);
    if (result) {
      lastError = ERROR_SUCCESS;
      break;
    } else {
      lastError = GetLastError();
    }
    Sleep(100);
    currentWaitMS += 100;
  }
  CloseServiceHandle(service);
  CloseServiceHandle(serviceManager);
  return lastError;
}

#ifndef ONLY_SERVICE_LAUNCHING

/**
 * Launch a service initiated action for a software update with the
 * specified arguments.
 *
 * @param  exePath The path of the executable to run
 * @param  argc    The total number of arguments in argv
 * @param  argv    An array of null terminated strings to pass to the exePath,
 *                 argv[0] must be the path to the updater.exe
 * @return ERROR_SUCCESS if successful
 */
DWORD
LaunchServiceSoftwareUpdateCommand(int argc, LPCWSTR* argv)
{
  // The service command is the same as the updater.exe command line except
  // it has 2 extra args: 1) The Path to udpater.exe, and 2) the command
  // being executed which is "software-update"
  LPCWSTR *updaterServiceArgv = new LPCWSTR[argc + 2];
  updaterServiceArgv[0] = L"MozillaMaintenance";
  updaterServiceArgv[1] = L"software-update";

  for (int i = 0; i < argc; ++i) {
    updaterServiceArgv[i + 2] = argv[i];
  }

  // Execute the service command by starting the service with
  // the passed in arguments.
  DWORD ret = StartServiceCommand(argc + 2, updaterServiceArgv);
  delete[] updaterServiceArgv;
  return ret;
}

/**
 * Joins a base directory path with a filename.
 *
 * @param  base  The base directory path of size MAX_PATH + 1
 * @param  extra The filename to append
 * @return TRUE if the file name was successful appended to base
 */
BOOL
PathAppendSafe(LPWSTR base, LPCWSTR extra)
{
  if (wcslen(base) + wcslen(extra) >= MAX_PATH) {
    return FALSE;
  }

  return PathAppendW(base, extra);
}

/**
 * Sets update.status to a specific failure code
 *
 * @param  updateDirPath The path of the update directory
 * @return TRUE if successful
 */
BOOL
WriteStatusFailure(LPCWSTR updateDirPath, int errorCode)
{
  // The temp file is not removed on failure since there is client code that
  // will remove it.
  WCHAR tmpUpdateStatusFilePath[MAX_PATH + 1] = { L'\0' };
  if (GetTempFileNameW(updateDirPath, L"svc", 0, tmpUpdateStatusFilePath) == 0) {
    return FALSE;
  }

  HANDLE tmpStatusFile = CreateFileW(tmpUpdateStatusFilePath, GENERIC_WRITE, 0,
                                     nullptr, CREATE_ALWAYS, 0, nullptr);
  if (tmpStatusFile == INVALID_HANDLE_VALUE) {
    return FALSE;
  }

  char failure[32];
  sprintf(failure, "failed: %d", errorCode);
  DWORD toWrite = strlen(failure);
  DWORD wrote;
  BOOL ok = WriteFile(tmpStatusFile, failure,
                      toWrite, &wrote, nullptr);
  CloseHandle(tmpStatusFile);

  if (!ok || wrote != toWrite) {
    return FALSE;
  }

  WCHAR updateStatusFilePath[MAX_PATH + 1] = { L'\0' };
  wcsncpy(updateStatusFilePath, updateDirPath, MAX_PATH);
  if (!PathAppendSafe(updateStatusFilePath, L"update.status")) {
    return FALSE;
  }

  if (MoveFileExW(tmpUpdateStatusFilePath, updateStatusFilePath,
                  MOVEFILE_REPLACE_EXISTING) == 0) {
    return FALSE;
  }

  return TRUE;
}

#endif

/**
 * Waits for a service to enter a stopped state.
 * This function does not stop the service, it just blocks until the service
 * is stopped.
 *
 * @param  serviceName     The service to wait for.
 * @param  maxWaitSeconds  The maximum number of seconds to wait
 * @return state of the service after a timeout or when stopped.
 *         A value of 255 is returned for an error. Typical values are:
 *         SERVICE_STOPPED 0x00000001
 *         SERVICE_START_PENDING 0x00000002
 *         SERVICE_STOP_PENDING 0x00000003
 *         SERVICE_RUNNING 0x00000004
 *         SERVICE_CONTINUE_PENDING 0x00000005
 *         SERVICE_PAUSE_PENDING 0x00000006
 *         SERVICE_PAUSED 0x00000007
 *         last status not set 0x000000CF
 *         Could no query status 0x000000DF
 *         Could not open service, access denied 0x000000EB
 *         Could not open service, invalid handle 0x000000EC
 *         Could not open service, invalid name 0x000000ED
 *         Could not open service, does not exist 0x000000EE
 *         Could not open service, other error 0x000000EF
 *         Could not open SCM, access denied 0x000000FD
 *         Could not open SCM, database does not exist 0x000000FE;
 *         Could not open SCM, other error 0x000000FF;
 * Note: The strange choice of error codes above SERVICE_PAUSED are chosen
 * in case Windows comes out with other service stats higher than 7, they
 * would likely call it 8 and above.  JS code that uses this in TestAUSHelper
 * only handles values up to 255 so that's why we don't use GetLastError
 * directly.
 */
DWORD
WaitForServiceStop(LPCWSTR serviceName, DWORD maxWaitSeconds)
{
  // 0x000000CF is defined above to be not set
  DWORD lastServiceState = 0x000000CF;

  // Get a handle to the SCM database.
  SC_HANDLE serviceManager = OpenSCManager(nullptr, nullptr,
                                           SC_MANAGER_CONNECT |
                                           SC_MANAGER_ENUMERATE_SERVICE);
  if (!serviceManager)  {
    DWORD lastError = GetLastError();
    switch(lastError) {
    case ERROR_ACCESS_DENIED:
      return 0x000000FD;
    case ERROR_DATABASE_DOES_NOT_EXIST:
      return 0x000000FE;
    default:
      return 0x000000FF;
    }
  }

  // Get a handle to the service.
  SC_HANDLE service = OpenServiceW(serviceManager,
                                   serviceName,
                                   SERVICE_QUERY_STATUS);
  if (!service) {
    DWORD lastError = GetLastError();
    CloseServiceHandle(serviceManager);
    switch(lastError) {
    case ERROR_ACCESS_DENIED:
      return 0x000000EB;
    case ERROR_INVALID_HANDLE:
      return 0x000000EC;
    case ERROR_INVALID_NAME:
      return 0x000000ED;
    case ERROR_SERVICE_DOES_NOT_EXIST:
      return 0x000000EE;
    default:
      return 0x000000EF;
    }
  }

  DWORD currentWaitMS = 0;
  SERVICE_STATUS_PROCESS ssp;
  ssp.dwCurrentState = lastServiceState;
  while (currentWaitMS < maxWaitSeconds * 1000) {
    DWORD bytesNeeded;
    if (!QueryServiceStatusEx(service, SC_STATUS_PROCESS_INFO, (LPBYTE)&ssp,
                              sizeof(SERVICE_STATUS_PROCESS), &bytesNeeded)) {
      DWORD lastError = GetLastError();
      switch (lastError) {
      case ERROR_INVALID_HANDLE:
        ssp.dwCurrentState = 0x000000D9;
        break;
      case ERROR_ACCESS_DENIED:
        ssp.dwCurrentState = 0x000000DA;
        break;
      case ERROR_INSUFFICIENT_BUFFER:
        ssp.dwCurrentState = 0x000000DB;
        break;
      case ERROR_INVALID_PARAMETER:
        ssp.dwCurrentState = 0x000000DC;
        break;
      case ERROR_INVALID_LEVEL:
        ssp.dwCurrentState = 0x000000DD;
        break;
      case ERROR_SHUTDOWN_IN_PROGRESS:
        ssp.dwCurrentState = 0x000000DE;
        break;
      // These 3 errors can occur when the service is not yet stopped but
      // it is stopping.
      case ERROR_INVALID_SERVICE_CONTROL:
      case ERROR_SERVICE_CANNOT_ACCEPT_CTRL:
      case ERROR_SERVICE_NOT_ACTIVE:
        currentWaitMS += 50;
        Sleep(50);
        continue;
      default:
        ssp.dwCurrentState = 0x000000DF;
      }

      // We couldn't query the status so just break out
      break;
    }

    // The service is already in use.
    if (ssp.dwCurrentState == SERVICE_STOPPED) {
      break;
    }
    currentWaitMS += 50;
    Sleep(50);
  }

  lastServiceState = ssp.dwCurrentState;
  CloseServiceHandle(service);
  CloseServiceHandle(serviceManager);
  return lastServiceState;
}

#ifndef ONLY_SERVICE_LAUNCHING

/**
 * Determines if there is at least one process running for the specified
 * application. A match will be found across any session for any user.
 *
 * @param process The process to check for existance
 * @return ERROR_NOT_FOUND if the process was not found
 *         ERROR_SUCCESS if the process was found and there were no errors
 *         Other Win32 system error code for other errors
**/
DWORD
IsProcessRunning(LPCWSTR filename)
{
  // Take a snapshot of all processes in the system.
  HANDLE snapshot = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
  if (INVALID_HANDLE_VALUE == snapshot) {
    return GetLastError();
  }

  PROCESSENTRY32W processEntry;
  processEntry.dwSize = sizeof(PROCESSENTRY32W);
  if (!Process32FirstW(snapshot, &processEntry)) {
    DWORD lastError = GetLastError();
    CloseHandle(snapshot);
    return lastError;
  }

  do {
    if (wcsicmp(filename, processEntry.szExeFile) == 0) {
      CloseHandle(snapshot);
      return ERROR_SUCCESS;
    }
  } while (Process32NextW(snapshot, &processEntry));
  CloseHandle(snapshot);
  return ERROR_NOT_FOUND;
}

/**
 * Waits for the specified applicaiton to exit.
 *
 * @param filename   The application to wait for.
 * @param maxSeconds The maximum amount of seconds to wait for all
 *                   instances of the application to exit.
 * @return  ERROR_SUCCESS if no instances of the application exist
 *          WAIT_TIMEOUT if the process is still running after maxSeconds.
 *          Any other Win32 system error code.
*/
DWORD
WaitForProcessExit(LPCWSTR filename, DWORD maxSeconds)
{
  DWORD applicationRunningError = WAIT_TIMEOUT;
  for(DWORD i = 0; i < maxSeconds; i++) {
    DWORD applicationRunningError = IsProcessRunning(filename);
    if (ERROR_NOT_FOUND == applicationRunningError) {
      return ERROR_SUCCESS;
    }
    Sleep(1000);
  }

  if (ERROR_SUCCESS == applicationRunningError) {
    return WAIT_TIMEOUT;
  }

  return applicationRunningError;
}

/**
 *  Determines if the fallback key exists or not
 *
 *  @return TRUE if the fallback key exists and there was no error checking
*/
BOOL
DoesFallbackKeyExist()
{
  HKEY testOnlyFallbackKey;
  if (RegOpenKeyExW(HKEY_LOCAL_MACHINE,
                    TEST_ONLY_FALLBACK_KEY_PATH, 0,
                    KEY_READ | KEY_WOW64_64KEY,
                    &testOnlyFallbackKey) != ERROR_SUCCESS) {
    return FALSE;
  }

  RegCloseKey(testOnlyFallbackKey);
  return TRUE;
}

#endif

/**
 * Determines if the file system for the specified file handle is local
 * @param file path to check the filesystem type for, must be at most MAX_PATH
 * @param isLocal out parameter which will hold TRUE if the drive is local
 * @return TRUE if the call succeeded
*/
BOOL
IsLocalFile(LPCWSTR file, BOOL &isLocal)
{
  WCHAR rootPath[MAX_PATH + 1] = { L'\0' };
  if (wcslen(file) > MAX_PATH) {
    return FALSE;
  }

  wcsncpy(rootPath, file, MAX_PATH);
  PathStripToRootW(rootPath);
  isLocal = GetDriveTypeW(rootPath) == DRIVE_FIXED;
  return TRUE;
}


/**
 * Determines the DWORD value of a registry key value
 *
 * @param key       The base key to where the value name exists
 * @param valueName The name of the value
 * @param retValue  Out parameter which will hold the value
 * @return TRUE on success
*/
static BOOL
GetDWORDValue(HKEY key, LPCWSTR valueName, DWORD &retValue)
{
  DWORD regDWORDValueSize = sizeof(DWORD);
  LONG retCode = RegQueryValueExW(key, valueName, 0, nullptr,
                                  reinterpret_cast<LPBYTE>(&retValue),
                                  &regDWORDValueSize);
  return ERROR_SUCCESS == retCode;
}

/**
 * Determines if the the system's elevation type allows
 * unprmopted elevation.
 *
 * @param isUnpromptedElevation Out parameter which specifies if unprompted
 *                              elevation is allowed.
 * @return TRUE if the user can actually elevate and the value was obtained
 *         successfully.
*/
BOOL
IsUnpromptedElevation(BOOL &isUnpromptedElevation)
{
  if (!UACHelper::CanUserElevate()) {
    return FALSE;
  }

  LPCWSTR UACBaseRegKey =
    L"SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Policies\\System";
  HKEY baseKey;
  LONG retCode = RegOpenKeyExW(HKEY_LOCAL_MACHINE,
                               UACBaseRegKey, 0,
                               KEY_READ, &baseKey);
  if (retCode != ERROR_SUCCESS) {
    return FALSE;
  }

  DWORD consent, secureDesktop;
  BOOL success = GetDWORDValue(baseKey, L"ConsentPromptBehaviorAdmin",
                               consent);
  success = success &&
            GetDWORDValue(baseKey, L"PromptOnSecureDesktop", secureDesktop);
  isUnpromptedElevation = !consent && !secureDesktop;

  RegCloseKey(baseKey);
  return success;
}