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Detener un servicio

Un programa de control de servicio puede detener un servicio mediante la función ControlService para enviar una solicitud de SERVICE_CONTROL_STOP. Si el administrador de control de servicios (SCM) recibe una solicitud de SERVICE_CONTROL_STOP para un servicio, indica al servicio que detenga reenviando la solicitud a la función ServiceMain del servicio. Sin embargo, si el SCM determina que otros servicios en ejecución dependen del servicio especificado, no reenviará la solicitud de detención. En su lugar, devuelve ERROR_DEPENDENT_SERVICES_RUNNING. Por lo tanto, para detener mediante programación este servicio, primero debe enumerar y detener sus servicios dependientes.

La función DoStopSvc del ejemplo siguiente muestra cómo detener un servicio y los servicios dependientes. La variable szSvcName es una variable global que contiene el nombre del servicio que se va a detener. Para obtener el ejemplo completo que establece esta variable, vea SvcControl.cpp.

//
// Purpose: 
//   Stops the service.
//
// Parameters:
//   None
// 
// Return value:
//   None
//
VOID __stdcall DoStopSvc()
{
    SERVICE_STATUS_PROCESS ssp;
    DWORD dwStartTime = GetTickCount();
    DWORD dwBytesNeeded;
    DWORD dwTimeout = 30000; // 30-second time-out
    DWORD dwWaitTime;

    // Get a handle to the SCM database. 
 
    schSCManager = OpenSCManager( 
        NULL,                    // local computer
        NULL,                    // ServicesActive database 
        SC_MANAGER_ALL_ACCESS);  // full access rights 
 
    if (NULL == schSCManager) 
    {
        printf("OpenSCManager failed (%d)\n", GetLastError());
        return;
    }

    // Get a handle to the service.

    schService = OpenService( 
        schSCManager,         // SCM database 
        szSvcName,            // name of service 
        SERVICE_STOP | 
        SERVICE_QUERY_STATUS | 
        SERVICE_ENUMERATE_DEPENDENTS);  
 
    if (schService == NULL)
    { 
        printf("OpenService failed (%d)\n", GetLastError()); 
        CloseServiceHandle(schSCManager);
        return;
    }    

    // Make sure the service is not already stopped.

    if ( !QueryServiceStatusEx( 
            schService, 
            SC_STATUS_PROCESS_INFO,
            (LPBYTE)&ssp, 
            sizeof(SERVICE_STATUS_PROCESS),
            &dwBytesNeeded ) )
    {
        printf("QueryServiceStatusEx failed (%d)\n", GetLastError()); 
        goto stop_cleanup;
    }

    if ( ssp.dwCurrentState == SERVICE_STOPPED )
    {
        printf("Service is already stopped.\n");
        goto stop_cleanup;
    }

    // If a stop is pending, wait for it.

    while ( ssp.dwCurrentState == SERVICE_STOP_PENDING ) 
    {
        printf("Service stop pending...\n");

        // Do not wait longer than the wait hint. A good interval is 
        // one-tenth of the wait hint but not less than 1 second  
        // and not more than 10 seconds. 
 
        dwWaitTime = ssp.dwWaitHint / 10;

        if( dwWaitTime < 1000 )
            dwWaitTime = 1000;
        else if ( dwWaitTime > 10000 )
            dwWaitTime = 10000;

        Sleep( dwWaitTime );

        if ( !QueryServiceStatusEx( 
                 schService, 
                 SC_STATUS_PROCESS_INFO,
                 (LPBYTE)&ssp, 
                 sizeof(SERVICE_STATUS_PROCESS),
                 &dwBytesNeeded ) )
        {
            printf("QueryServiceStatusEx failed (%d)\n", GetLastError()); 
            goto stop_cleanup;
        }

        if ( ssp.dwCurrentState == SERVICE_STOPPED )
        {
            printf("Service stopped successfully.\n");
            goto stop_cleanup;
        }

        if ( GetTickCount() - dwStartTime > dwTimeout )
        {
            printf("Service stop timed out.\n");
            goto stop_cleanup;
        }
    }

    // If the service is running, dependencies must be stopped first.

    StopDependentServices();

    // Send a stop code to the service.

    if ( !ControlService( 
            schService, 
            SERVICE_CONTROL_STOP, 
            (LPSERVICE_STATUS) &ssp ) )
    {
        printf( "ControlService failed (%d)\n", GetLastError() );
        goto stop_cleanup;
    }

    // Wait for the service to stop.

    while ( ssp.dwCurrentState != SERVICE_STOPPED ) 
    {
        Sleep( ssp.dwWaitHint );
        if ( !QueryServiceStatusEx( 
                schService, 
                SC_STATUS_PROCESS_INFO,
                (LPBYTE)&ssp, 
                sizeof(SERVICE_STATUS_PROCESS),
                &dwBytesNeeded ) )
        {
            printf( "QueryServiceStatusEx failed (%d)\n", GetLastError() );
            goto stop_cleanup;
        }

        if ( ssp.dwCurrentState == SERVICE_STOPPED )
            break;

        if ( GetTickCount() - dwStartTime > dwTimeout )
        {
            printf( "Wait timed out\n" );
            goto stop_cleanup;
        }
    }
    printf("Service stopped successfully\n");

stop_cleanup:
    CloseServiceHandle(schService); 
    CloseServiceHandle(schSCManager);
}

BOOL __stdcall StopDependentServices()
{
    DWORD i;
    DWORD dwBytesNeeded;
    DWORD dwCount;

    LPENUM_SERVICE_STATUS   lpDependencies = NULL;
    ENUM_SERVICE_STATUS     ess;
    SC_HANDLE               hDepService;
    SERVICE_STATUS_PROCESS  ssp;

    DWORD dwStartTime = GetTickCount();
    DWORD dwTimeout = 30000; // 30-second time-out

    // Pass a zero-length buffer to get the required buffer size.
    if ( EnumDependentServices( schService, SERVICE_ACTIVE, 
         lpDependencies, 0, &dwBytesNeeded, &dwCount ) ) 
    {
         // If the Enum call succeeds, then there are no dependent
         // services, so do nothing.
         return TRUE;
    } 
    else 
    {
        if ( GetLastError() != ERROR_MORE_DATA )
            return FALSE; // Unexpected error

        // Allocate a buffer for the dependencies.
        lpDependencies = (LPENUM_SERVICE_STATUS) HeapAlloc( 
            GetProcessHeap(), HEAP_ZERO_MEMORY, dwBytesNeeded );
  
        if ( !lpDependencies )
            return FALSE;

        __try {
            // Enumerate the dependencies.
            if ( !EnumDependentServices( schService, SERVICE_ACTIVE, 
                lpDependencies, dwBytesNeeded, &dwBytesNeeded,
                &dwCount ) )
            return FALSE;

            for ( i = 0; i < dwCount; i++ ) 
            {
                ess = *(lpDependencies + i);
                // Open the service.
                hDepService = OpenService( schSCManager, 
                   ess.lpServiceName, 
                   SERVICE_STOP | SERVICE_QUERY_STATUS );

                if ( !hDepService )
                   return FALSE;

                __try {
                    // Send a stop code.
                    if ( !ControlService( hDepService, 
                            SERVICE_CONTROL_STOP,
                            (LPSERVICE_STATUS) &ssp ) )
                    return FALSE;

                    // Wait for the service to stop.
                    while ( ssp.dwCurrentState != SERVICE_STOPPED ) 
                    {
                        Sleep( ssp.dwWaitHint );
                        if ( !QueryServiceStatusEx( 
                                hDepService, 
                                SC_STATUS_PROCESS_INFO,
                                (LPBYTE)&ssp, 
                                sizeof(SERVICE_STATUS_PROCESS),
                                &dwBytesNeeded ) )
                        return FALSE;

                        if ( ssp.dwCurrentState == SERVICE_STOPPED )
                            break;

                        if ( GetTickCount() - dwStartTime > dwTimeout )
                            return FALSE;
                    }
                } 
                __finally 
                {
                    // Always release the service handle.
                    CloseServiceHandle( hDepService );
                }
            }
        } 
        __finally 
        {
            // Always free the enumeration buffer.
            HeapFree( GetProcessHeap(), 0, lpDependencies );
        }
    } 
    return TRUE;
}

Ejemplo de servicio completo