Run an executable as a Windows Service

Introduction

This is a reference on running an executable as a Windows Service. In the code, the following ideas are provided along with a reference on running an exe from a service:

1. Writing a Windows Service
2. Installing a Windows Service
3. Uninstalling a Windows Service
4. Debugging a Windows Service

Using the code

The API call used in the service code is very well documented in MSDN. We need to create a project with the code below to start using it.

#include "windows.h"
#include "tchar.h"

#define _MAX_PATH   260

TCHAR* serviceName = ""; 
TCHAR* exePath = "";
STARTUPINFO si;
PROCESS_INFORMATION pi;
SERVICE_STATUS serviceStatus;
SERVICE_STATUS_HANDLE serviceStatusHandle = 0;
HANDLE stopServiceEvent = 0;
DWORD exitCode = -1;

void StartExe()
{
    ZeroMemory( &si, sizeof(si) );
    si.cb = sizeof(si);
    ZeroMemory( &pi, sizeof(pi) );

    // Start the child process. 
    CreateProcess( NULL, // No module name (use command line). 
        exePath, // Command line. 
        NULL,             // Process handle not inheritable. 
        NULL,             // Thread handle not inheritable. 
        FALSE,            // Set handle inheritance to FALSE. 
        0,                // No creation flags. 
        NULL,             // Use parent's environment block. 
        NULL,             // Use parent's starting directory. 
        &si,              // Pointer to STARTUPINFO structure.
        &pi );            // Pointer to PROCESS_INFORMATION structure.
}

void WINAPI ServiceControlHandler( DWORD controlCode )
{
    switch ( controlCode )
    {
        case SERVICE_CONTROL_INTERROGATE:
            break;

        case SERVICE_CONTROL_SHUTDOWN:
        case SERVICE_CONTROL_STOP:

            TerminateProcess(pi.hProcess, 
               GetExitCodeProcess(pi.hProcess,&exitCode));

            serviceStatus.dwCurrentState = SERVICE_STOP_PENDING;
            SetServiceStatus( serviceStatusHandle, &serviceStatus );

            SetEvent( stopServiceEvent );
            return;

        case SERVICE_CONTROL_PAUSE:
            break;

        case SERVICE_CONTROL_CONTINUE:
            break;

        default:
            if ( controlCode >= 128 && controlCode <= 255 )
                // user defined control code
                break;
            else
                // unrecognised control code
                break;
    }

    SetServiceStatus( serviceStatusHandle, &serviceStatus );
}

void WINAPI ServiceMain( DWORD /*argc*/, TCHAR* /*argv*/[] )
{
    // initialise service status
    serviceStatus.dwServiceType = SERVICE_WIN32;
    serviceStatus.dwCurrentState = SERVICE_STOPPED;
    serviceStatus.dwControlsAccepted = 0;
    serviceStatus.dwWin32ExitCode = NO_ERROR;
    serviceStatus.dwServiceSpecificExitCode = NO_ERROR;
    serviceStatus.dwCheckPoint = 0;
    serviceStatus.dwWaitHint = 0;

    serviceStatusHandle = RegisterServiceCtrlHandler( serviceName, 
                                          ServiceControlHandler );

    if ( serviceStatusHandle )
    {
        // service is starting
        serviceStatus.dwCurrentState = SERVICE_START_PENDING;
        SetServiceStatus( serviceStatusHandle, &serviceStatus );

        // do initialisation here
        stopServiceEvent = CreateEvent( 0, FALSE, FALSE, 0 );

        // running
        serviceStatus.dwControlsAccepted |= 
               (SERVICE_ACCEPT_STOP | SERVICE_ACCEPT_SHUTDOWN);
        serviceStatus.dwCurrentState = SERVICE_RUNNING;
        SetServiceStatus( serviceStatusHandle, &serviceStatus );

        StartExe();
        WaitForSingleObject( stopServiceEvent, INFINITE ); 

        // service was stopped
        serviceStatus.dwCurrentState = SERVICE_STOP_PENDING;
        SetServiceStatus( serviceStatusHandle, &serviceStatus );

        // do cleanup here
        CloseHandle( stopServiceEvent );
        stopServiceEvent = 0;

        // service is now stopped
        serviceStatus.dwControlsAccepted &= ~(SERVICE_ACCEPT_STOP | SERVICE_ACCEPT_SHUTDOWN);
        serviceStatus.dwCurrentState = SERVICE_STOPPED;
        SetServiceStatus( serviceStatusHandle, &serviceStatus );
    }
}

void RunService()
{
    SERVICE_TABLE_ENTRY serviceTable[] =
    {
        { serviceName, ServiceMain },
        { 0, 0 }
    };

    StartServiceCtrlDispatcher( serviceTable );
}

void InstallService()
{
    SC_HANDLE serviceControlManager = OpenSCManager( 0, 0, SC_MANAGER_CREATE_SERVICE );

    if ( serviceControlManager )
    {
        TCHAR path[ _MAX_PATH + 1 ];
        if ( GetModuleFileName( 0, path, sizeof(path)/sizeof(path[0]) ) > 0 )
        {
            SC_HANDLE service = CreateService( serviceControlManager,
                            serviceName, serviceName,
                            SERVICE_ALL_ACCESS, SERVICE_WIN32_OWN_PROCESS,
                            SERVICE_AUTO_START, SERVICE_ERROR_IGNORE, path,
                            0, 0, 0, 0, 0 );
            if ( service )
                CloseServiceHandle( service );
        }

        CloseServiceHandle( serviceControlManager );
    }
}

void UninstallService()
{
    SC_HANDLE serviceControlManager = OpenSCManager( 0, 0, SC_MANAGER_CONNECT );

    if ( serviceControlManager )
    {
        SC_HANDLE service = OpenService( serviceControlManager,
            serviceName, SERVICE_QUERY_STATUS | DELETE );
        if ( service )
        {
            SERVICE_STATUS serviceStatus;
            if ( QueryServiceStatus( service, &serviceStatus ) )
            {
                if ( serviceStatus.dwCurrentState == SERVICE_STOPPED )
                    DeleteService( service );
            }

            CloseServiceHandle( service );
        }

        CloseServiceHandle( serviceControlManager );
    }
}

int _tmain( int argc, TCHAR* argv[] )
{

    if ( argc > 2 && lstrcmpi( argv[1], TEXT("install") ) == 0 )
    {
        serviceName = argv[2];
        InstallService();
    }
    else if ( argc > 1 && lstrcmpi( argv[1], TEXT("uninstall") ) == 0 )
    {
        UninstallService();
    }
    else if( argc > 2 && lstrcmpi( argv[1], TEXT("start") ) == 0 )
    {
        exePath = argv[2];
        RunService();
    }
    else
    {
        //show error message
    }

    return 0;
}

For debugging the code, write the below code at the beginning of the _tmain function:

__asm
{
  int 3
}

This will create a break while running the service.

History

Do contact me for any updates or queries at somenshaw at gmail.com.