/*
 * Deskflow -- mouse and keyboard sharing utility
 * Copyright (C) 2012-2016 Symless Ltd.
 * Copyright (C) 2002 Chris Schoeneman
 *
 * This package is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * found in the file LICENSE that should have accompanied this file.
 *
 * This package is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "arch/win32/ArchDaemonWindows.h"
#include "arch/Arch.h"
#include "arch/win32/ArchMiscWindows.h"
#include "arch/win32/XArchWindows.h"
#include "common/stdvector.h"

#include <sstream>

//
// ArchDaemonWindows
//

ArchDaemonWindows *ArchDaemonWindows::s_daemon = NULL;

ArchDaemonWindows::ArchDaemonWindows() : m_daemonThreadID(0)
{
  m_quitMessage = RegisterWindowMessage("DeskflowDaemonExit");
}

ArchDaemonWindows::~ArchDaemonWindows()
{
  // do nothing
}

int ArchDaemonWindows::runDaemon(RunFunc runFunc)
{
  assert(s_daemon != NULL);
  return s_daemon->doRunDaemon(runFunc);
}

void ArchDaemonWindows::daemonRunning(bool running)
{
  if (s_daemon != NULL) {
    s_daemon->doDaemonRunning(running);
  }
}

UINT ArchDaemonWindows::getDaemonQuitMessage()
{
  if (s_daemon != NULL) {
    return s_daemon->doGetDaemonQuitMessage();
  } else {
    return 0;
  }
}

void ArchDaemonWindows::daemonFailed(int result)
{
  assert(s_daemon != NULL);
  throw XArchDaemonRunFailed(result);
}

void ArchDaemonWindows::installDaemon(
    const char *name, const char *description, const char *pathname, const char *commandLine, const char *dependencies
)
{
  // open service manager
  SC_HANDLE mgr = OpenSCManager(NULL, NULL, GENERIC_WRITE);
  if (mgr == NULL) {
    // can't open service manager
    throw XArchDaemonInstallFailed(new XArchEvalWindows);
  }

  // create the service
  SC_HANDLE service = CreateService(
      mgr, name, name, 0, SERVICE_WIN32_OWN_PROCESS | SERVICE_INTERACTIVE_PROCESS, SERVICE_AUTO_START,
      SERVICE_ERROR_NORMAL, pathname, NULL, NULL, dependencies, NULL, NULL
  );

  if (service == NULL) {
    // can't create service
    DWORD err = GetLastError();
    if (err != ERROR_SERVICE_EXISTS) {
      CloseServiceHandle(mgr);
      throw XArchDaemonInstallFailed(new XArchEvalWindows(err));
    }
  } else {
    // done with service (but only try to close if not null)
    CloseServiceHandle(service);
  }

  // done with manager
  CloseServiceHandle(mgr);

  // open the registry key for this service
  HKEY key = openNTServicesKey();
  key = ArchMiscWindows::addKey(key, name);
  if (key == NULL) {
    // can't open key
    DWORD err = GetLastError();
    try {
      uninstallDaemon(name);
    } catch (...) {
      // ignore
    }
    throw XArchDaemonInstallFailed(new XArchEvalWindows(err));
  }

  // set the description
  ArchMiscWindows::setValue(key, _T("Description"), description);

  // set command line
  key = ArchMiscWindows::addKey(key, _T("Parameters"));
  if (key == NULL) {
    // can't open key
    DWORD err = GetLastError();
    ArchMiscWindows::closeKey(key);
    try {
      uninstallDaemon(name);
    } catch (...) {
      // ignore
    }
    throw XArchDaemonInstallFailed(new XArchEvalWindows(err));
  }
  ArchMiscWindows::setValue(key, _T("CommandLine"), commandLine);

  // done with registry
  ArchMiscWindows::closeKey(key);
}

void ArchDaemonWindows::uninstallDaemon(const char *name)
{
  // remove parameters for this service.  ignore failures.
  HKEY key = openNTServicesKey();
  key = ArchMiscWindows::openKey(key, name);
  if (key != NULL) {
    ArchMiscWindows::deleteKey(key, _T("Parameters"));
    ArchMiscWindows::closeKey(key);
  }

  // open service manager
  SC_HANDLE mgr = OpenSCManager(NULL, NULL, GENERIC_WRITE);
  if (mgr == NULL) {
    // can't open service manager
    throw XArchDaemonUninstallFailed(new XArchEvalWindows);
  }

  // open the service.  oddly, you must open a service to delete it.
  SC_HANDLE service = OpenService(mgr, name, DELETE | SERVICE_STOP);
  if (service == NULL) {
    DWORD err = GetLastError();
    CloseServiceHandle(mgr);
    if (err != ERROR_SERVICE_DOES_NOT_EXIST) {
      throw XArchDaemonUninstallFailed(new XArchEvalWindows(err));
    }
    throw XArchDaemonUninstallNotInstalled(new XArchEvalWindows(err));
  }

  // stop the service.  we don't care if we fail.
  SERVICE_STATUS status;
  ControlService(service, SERVICE_CONTROL_STOP, &status);

  // delete the service
  const bool okay = (DeleteService(service) == 0);
  const DWORD err = GetLastError();

  // clean up
  CloseServiceHandle(service);
  CloseServiceHandle(mgr);

  // give windows a chance to remove the service before
  // we check if it still exists.
  ARCH->sleep(1);

  // handle failure.  ignore error if service isn't installed anymore.
  if (!okay && isDaemonInstalled(name)) {
    if (err == ERROR_SUCCESS) {
      // this seems to occur even though the uninstall was successful.
      // it could be a timing issue, i.e., isDaemonInstalled is
      // called too soon. i've added a sleep to try and stop this.
      return;
    }
    if (err == ERROR_IO_PENDING) {
      // this seems to be a spurious error
      return;
    }
    if (err != ERROR_SERVICE_MARKED_FOR_DELETE) {
      throw XArchDaemonUninstallFailed(new XArchEvalWindows(err));
    }
    throw XArchDaemonUninstallNotInstalled(new XArchEvalWindows(err));
  }
}

int ArchDaemonWindows::daemonize(const char *name, DaemonFunc func)
{
  assert(name != NULL);
  assert(func != NULL);

  // save daemon function
  m_daemonFunc = func;

  // construct the service entry
  SERVICE_TABLE_ENTRY entry[2];
  entry[0].lpServiceName = const_cast<char *>(name);
  entry[0].lpServiceProc = &ArchDaemonWindows::serviceMainEntry;
  entry[1].lpServiceName = NULL;
  entry[1].lpServiceProc = NULL;

  // hook us up to the service control manager.  this won't return
  // (if successful) until the processes have terminated.
  s_daemon = this;
  if (StartServiceCtrlDispatcher(entry) == 0) {
    // StartServiceCtrlDispatcher failed
    s_daemon = NULL;
    throw XArchDaemonFailed(new XArchEvalWindows);
  }

  s_daemon = NULL;
  return m_daemonResult;
}

bool ArchDaemonWindows::canInstallDaemon(const char * /*name*/)
{
  // check if we can open service manager for write
  SC_HANDLE mgr = OpenSCManager(NULL, NULL, GENERIC_WRITE);
  if (mgr == NULL) {
    return false;
  }
  CloseServiceHandle(mgr);

  // check if we can open the registry key
  HKEY key = openNTServicesKey();
  ArchMiscWindows::closeKey(key);

  return (key != NULL);
}

bool ArchDaemonWindows::isDaemonInstalled(const char *name)
{
  // open service manager
  SC_HANDLE mgr = OpenSCManager(NULL, NULL, GENERIC_READ);
  if (mgr == NULL) {
    return false;
  }

  // open the service
  SC_HANDLE service = OpenService(mgr, name, GENERIC_READ);

  // clean up
  if (service != NULL) {
    CloseServiceHandle(service);
  }
  CloseServiceHandle(mgr);

  return (service != NULL);
}

HKEY ArchDaemonWindows::openNTServicesKey()
{
  static const char *s_keyNames[] = {_T("SYSTEM"), _T("CurrentControlSet"), _T("Services"), NULL};

  return ArchMiscWindows::addKey(HKEY_LOCAL_MACHINE, s_keyNames);
}

bool ArchDaemonWindows::isRunState(DWORD state)
{
  switch (state) {
  case SERVICE_START_PENDING:
  case SERVICE_CONTINUE_PENDING:
  case SERVICE_RUNNING:
    return true;

  default:
    return false;
  }
}

int ArchDaemonWindows::doRunDaemon(RunFunc run)
{
  // should only be called from DaemonFunc
  assert(m_serviceMutex != NULL);
  assert(run != NULL);

  // create message queue for this thread
  MSG dummy;
  PeekMessage(&dummy, NULL, 0, 0, PM_NOREMOVE);

  int result = 0;
  ARCH->lockMutex(m_serviceMutex);
  m_daemonThreadID = GetCurrentThreadId();
  while (m_serviceState != SERVICE_STOPPED) {
    // wait until we're told to start
    while (!isRunState(m_serviceState) && m_serviceState != SERVICE_STOP_PENDING) {
      ARCH->waitCondVar(m_serviceCondVar, m_serviceMutex, -1.0);
    }

    // run unless told to stop
    if (m_serviceState != SERVICE_STOP_PENDING) {
      ARCH->unlockMutex(m_serviceMutex);
      try {
        result = run();
      } catch (...) {
        ARCH->lockMutex(m_serviceMutex);
        setStatusError(0);
        m_serviceState = SERVICE_STOPPED;
        setStatus(m_serviceState);
        ARCH->broadcastCondVar(m_serviceCondVar);
        ARCH->unlockMutex(m_serviceMutex);
        throw;
      }
      ARCH->lockMutex(m_serviceMutex);
    }

    // notify of new state
    if (m_serviceState == SERVICE_PAUSE_PENDING) {
      m_serviceState = SERVICE_PAUSED;
    } else {
      m_serviceState = SERVICE_STOPPED;
    }
    setStatus(m_serviceState);
    ARCH->broadcastCondVar(m_serviceCondVar);
  }
  ARCH->unlockMutex(m_serviceMutex);
  return result;
}

void ArchDaemonWindows::doDaemonRunning(bool running)
{
  ARCH->lockMutex(m_serviceMutex);
  if (running) {
    m_serviceState = SERVICE_RUNNING;
    setStatus(m_serviceState);
    ARCH->broadcastCondVar(m_serviceCondVar);
  }
  ARCH->unlockMutex(m_serviceMutex);
}

UINT ArchDaemonWindows::doGetDaemonQuitMessage()
{
  return m_quitMessage;
}

void ArchDaemonWindows::setStatus(DWORD state)
{
  setStatus(state, 0, 0);
}

void ArchDaemonWindows::setStatus(DWORD state, DWORD step, DWORD waitHint)
{
  assert(s_daemon != NULL);

  SERVICE_STATUS status;
  status.dwServiceType = SERVICE_WIN32_OWN_PROCESS | SERVICE_INTERACTIVE_PROCESS;
  status.dwCurrentState = state;
  status.dwControlsAccepted = SERVICE_ACCEPT_STOP | SERVICE_ACCEPT_PAUSE_CONTINUE | SERVICE_ACCEPT_SHUTDOWN;
  status.dwWin32ExitCode = NO_ERROR;
  status.dwServiceSpecificExitCode = 0;
  status.dwCheckPoint = step;
  status.dwWaitHint = waitHint;
  SetServiceStatus(s_daemon->m_statusHandle, &status);
}

void ArchDaemonWindows::setStatusError(DWORD error)
{
  assert(s_daemon != NULL);

  SERVICE_STATUS status;
  status.dwServiceType = SERVICE_WIN32_OWN_PROCESS | SERVICE_INTERACTIVE_PROCESS;
  status.dwCurrentState = SERVICE_STOPPED;
  status.dwControlsAccepted = SERVICE_ACCEPT_STOP | SERVICE_ACCEPT_PAUSE_CONTINUE | SERVICE_ACCEPT_SHUTDOWN;
  status.dwWin32ExitCode = ERROR_SERVICE_SPECIFIC_ERROR;
  status.dwServiceSpecificExitCode = error;
  status.dwCheckPoint = 0;
  status.dwWaitHint = 0;
  SetServiceStatus(s_daemon->m_statusHandle, &status);
}

void ArchDaemonWindows::serviceMain(DWORD argc, LPTSTR *argvIn)
{
  using ArgList = std::vector<LPCTSTR>;
  using Arguments = std::vector<std::string>;
  const char **argv = const_cast<const char **>(argvIn);

  // create synchronization objects
  m_serviceMutex = ARCH->newMutex();
  m_serviceCondVar = ARCH->newCondVar();

  // register our service handler function
  m_statusHandle = RegisterServiceCtrlHandler(argv[0], &ArchDaemonWindows::serviceHandlerEntry);
  if (m_statusHandle == 0) {
    // cannot start as service
    m_daemonResult = -1;
    ARCH->closeCondVar(m_serviceCondVar);
    ARCH->closeMutex(m_serviceMutex);
    return;
  }

  // tell service control manager that we're starting
  m_serviceState = SERVICE_START_PENDING;
  setStatus(m_serviceState, 0, 10000);

  std::string commandLine;

  // if no arguments supplied then try getting them from the registry.
  // the first argument doesn't count because it's the service name.
  Arguments args;
  ArgList myArgv;
  if (argc <= 1) {
    // read command line
    HKEY key = openNTServicesKey();
    key = ArchMiscWindows::openKey(key, argvIn[0]);
    key = ArchMiscWindows::openKey(key, _T("Parameters"));
    if (key != NULL) {
      commandLine = ArchMiscWindows::readValueString(key, _T("CommandLine"));
    }

    // if the command line isn't empty then parse and use it
    if (!commandLine.empty()) {
      // parse, honoring double quoted substrings
      std::string::size_type i = commandLine.find_first_not_of(" \t");
      while (i != std::string::npos && i != commandLine.size()) {
        // find end of string
        std::string::size_type e;
        if (commandLine[i] == '\"') {
          // quoted.  find closing quote.
          ++i;
          e = commandLine.find("\"", i);

          // whitespace must follow closing quote
          if (e == std::string::npos ||
              (e + 1 != commandLine.size() && commandLine[e + 1] != ' ' && commandLine[e + 1] != '\t')) {
            args.clear();
            break;
          }

          // extract
          args.push_back(commandLine.substr(i, e - i));
          i = e + 1;
        } else {
          // unquoted.  find next whitespace.
          e = commandLine.find_first_of(" \t", i);
          if (e == std::string::npos) {
            e = commandLine.size();
          }

          // extract
          args.push_back(commandLine.substr(i, e - i));
          i = e + 1;
        }

        // next argument
        i = commandLine.find_first_not_of(" \t", i);
      }

      // service name goes first
      myArgv.push_back(argv[0]);

      // get pointers
      for (size_t j = 0; j < args.size(); ++j) {
        myArgv.push_back(args[j].c_str());
      }

      // adjust argc/argv
      argc = (DWORD)myArgv.size();
      argv = &myArgv[0];
    }
  }

  m_commandLine = commandLine;

  try {
    // invoke daemon function
    m_daemonResult = m_daemonFunc(static_cast<int>(argc), argv);
  } catch (XArchDaemonRunFailed &e) {
    setStatusError(e.m_result);
    m_daemonResult = -1;
  } catch (...) {
    setStatusError(1);
    m_daemonResult = -1;
  }

  // clean up
  ARCH->closeCondVar(m_serviceCondVar);
  ARCH->closeMutex(m_serviceMutex);

  // we're going to exit now, so set status to stopped
  m_serviceState = SERVICE_STOPPED;
  setStatus(m_serviceState, 0, 10000);
}

void WINAPI ArchDaemonWindows::serviceMainEntry(DWORD argc, LPTSTR *argv)
{
  s_daemon->serviceMain(argc, argv);
}

void ArchDaemonWindows::serviceHandler(DWORD ctrl)
{
  assert(m_serviceMutex != NULL);
  assert(m_serviceCondVar != NULL);

  ARCH->lockMutex(m_serviceMutex);

  // ignore request if service is already stopped
  if (s_daemon == NULL || m_serviceState == SERVICE_STOPPED) {
    if (s_daemon != NULL) {
      setStatus(m_serviceState);
    }
    ARCH->unlockMutex(m_serviceMutex);
    return;
  }

  switch (ctrl) {
  case SERVICE_CONTROL_PAUSE:
    m_serviceState = SERVICE_PAUSE_PENDING;
    setStatus(m_serviceState, 0, 5000);
    PostThreadMessage(m_daemonThreadID, m_quitMessage, 0, 0);
    while (isRunState(m_serviceState)) {
      ARCH->waitCondVar(m_serviceCondVar, m_serviceMutex, -1.0);
    }
    break;

  case SERVICE_CONTROL_CONTINUE:
    // FIXME -- maybe should flush quit messages from queue
    m_serviceState = SERVICE_CONTINUE_PENDING;
    setStatus(m_serviceState, 0, 5000);
    ARCH->broadcastCondVar(m_serviceCondVar);
    break;

  case SERVICE_CONTROL_STOP:
  case SERVICE_CONTROL_SHUTDOWN:
    m_serviceState = SERVICE_STOP_PENDING;
    setStatus(m_serviceState, 0, 5000);
    PostThreadMessage(m_daemonThreadID, m_quitMessage, 0, 0);
    ARCH->broadcastCondVar(m_serviceCondVar);
    while (isRunState(m_serviceState)) {
      ARCH->waitCondVar(m_serviceCondVar, m_serviceMutex, -1.0);
    }
    break;

  default:
    // unknown service command
    // fall through

  case SERVICE_CONTROL_INTERROGATE:
    setStatus(m_serviceState);
    break;
  }

  ARCH->unlockMutex(m_serviceMutex);
}

void WINAPI ArchDaemonWindows::serviceHandlerEntry(DWORD ctrl)
{
  s_daemon->serviceHandler(ctrl);
}

void ArchDaemonWindows::start(const char *name)
{
  // open service manager
  SC_HANDLE mgr = OpenSCManager(NULL, NULL, GENERIC_READ);
  if (mgr == NULL) {
    throw XArchDaemonFailed(new XArchEvalWindows());
  }

  // open the service
  SC_HANDLE service = OpenService(mgr, name, SERVICE_START);

  if (service == NULL) {
    CloseServiceHandle(mgr);
    throw XArchDaemonFailed(new XArchEvalWindows());
  }

  // start the service
  if (!StartService(service, 0, NULL)) {
    throw XArchDaemonFailed(new XArchEvalWindows());
  }
}

void ArchDaemonWindows::stop(const char *name)
{
  // open service manager
  SC_HANDLE mgr = OpenSCManager(NULL, NULL, GENERIC_READ);
  if (mgr == NULL) {
    throw XArchDaemonFailed(new XArchEvalWindows());
  }

  // open the service
  SC_HANDLE service = OpenService(mgr, name, SERVICE_STOP | SERVICE_QUERY_STATUS);

  if (service == NULL) {
    CloseServiceHandle(mgr);
    throw XArchDaemonFailed(new XArchEvalWindows());
  }

  // ask the service to stop, asynchronously
  SERVICE_STATUS ss;
  if (!ControlService(service, SERVICE_CONTROL_STOP, &ss)) {
    DWORD dwErrCode = GetLastError();
    if (dwErrCode != ERROR_SERVICE_NOT_ACTIVE) {
      throw XArchDaemonFailed(new XArchEvalWindows());
    }
  }
}

void ArchDaemonWindows::installDaemon()
{
  // install default daemon if not already installed.
  if (!isDaemonInstalled(DEFAULT_DAEMON_NAME)) {
    char path[MAX_PATH];
    GetModuleFileName(ArchMiscWindows::instanceWin32(), path, MAX_PATH);

    // wrap in quotes so a malicious user can't start \Program.exe as admin.
    std::stringstream ss;
    ss << '"';
    ss << path;
    ss << '"';

    installDaemon(DEFAULT_DAEMON_NAME, DEFAULT_DAEMON_INFO, ss.str().c_str(), "", "");
  }

  start(DEFAULT_DAEMON_NAME);
}

void ArchDaemonWindows::uninstallDaemon()
{
  // remove legacy services if installed.
  if (isDaemonInstalled(LEGACY_SERVER_DAEMON_NAME)) {
    uninstallDaemon(LEGACY_SERVER_DAEMON_NAME);
  }
  if (isDaemonInstalled(LEGACY_CLIENT_DAEMON_NAME)) {
    uninstallDaemon(LEGACY_CLIENT_DAEMON_NAME);
  }

  // remove new service if installed.
  if (isDaemonInstalled(DEFAULT_DAEMON_NAME)) {
    uninstallDaemon(DEFAULT_DAEMON_NAME);
  }
}
