ControlService

ControlService

The ControlService function sends a control code to a service.

BOOL ControlService(
  SC_HANDLE hService,
  DWORD dwControl,
  LPSERVICE_STATUS lpServiceStatus
);

Parameters

hService

[in] Handle to the service. This handle is returned by the OpenService or CreateService function. The access rights required for this handle depend on the dwControl code requested.

dwControl

[in] This parameter can be one of the following control codes.

Control code	Meaning
SERVICE_CONTROL_CONTINUE 0x00000003	Notifies a paused service that it should resume. The hService handle must have the SERVICE_PAUSE_CONTINUE access right.
SERVICE_CONTROL_INTERROGATE 0x00000004	Notifies a service that it should report its current status information to the service control manager. The hService handle must have the SERVICE_INTERROGATE access right.
SERVICE_CONTROL_NETBINDADD 0x00000007	Notifies a network service that there is a new component for binding. The hService handle must have the SERVICE_PAUSE_CONTINUE access right. However, this control code has been deprecated; use Plug and Play functionality instead. Windows NT:  This value is not supported.
SERVICE_CONTROL_NETBINDDISABLE 0x0000000A	Notifies a network service that one of its bindings has been disabled. The hService handle must have the SERVICE_PAUSE_CONTINUE access right. However, this control code has been deprecated; use Plug and Play functionality instead. Windows NT:  This value is not supported.
SERVICE_CONTROL_NETBINDENABLE 0x00000009	Notifies a network service that a disabled binding has been enabled. The hService handle must have the SERVICE_PAUSE_CONTINUE access right. However, this control code has been deprecated; use Plug and Play functionality instead. Windows NT:  This value is not supported.
SERVICE_CONTROL_NETBINDREMOVE 0x00000008	Notifies a network service that that a component for binding has been removed. The hService handle must have the SERVICE_PAUSE_CONTINUE access right. However, this control code has been deprecated; use Plug and Play functionality instead. Windows NT:  This value is not supported.
SERVICE_CONTROL_PARAMCHANGE 0x00000006	Notifies a service that its startup parameters have changed. The hService handle must have the SERVICE_PAUSE_CONTINUE access right. Windows NT:  This value is not supported.
SERVICE_CONTROL_PAUSE 0x00000002	Notifies a service that it should pause. The hService handle must have the SERVICE_PAUSE_CONTINUE access right.
SERVICE_CONTROL_STOP 0x00000001	Notifies a service that it should stop. The hService handle must have the SERVICE_STOP access right. After sending the stop request to a service, you should not send other controls to the service.

This value can also be a user-defined control code, as described in the following table.

Control code	Meaning
Range 128 to 255	The service defines the action associated with the control code. The hService handle must have the SERVICE_USER_DEFINED_CONTROL access right.

lpServiceStatus

[out] Pointer to a SERVICE_STATUS structure that receives the latest service status information. The information returned reflects the most recent status that the service reported to the service control manager.

The service control manager fills in the structure only when ControlService returns one of the following error codes: NO_ERROR, ERROR_INVALID_SERVICE_CONTROL, ERROR_SERVICE_CANNOT_ACCEPT_CTRL, or ERROR_SERVICE_NOT_ACTIVE. Otherwise, the structure is not filled in.

Return Values

If the function succeeds, the return value is nonzero.

If the function fails, the return value is zero. To get extended error information, call GetLastError.

The following error codes can be set by the service control manager. Other error codes can be set by the registry functions that are called by the service control manager.

Return code	Description
ERROR_ACCESS_DENIED	The handle does not have the required access right.
ERROR_DEPENDENT_SERVICES_RUNNING	The service cannot be stopped because other running services are dependent on it.
ERROR_INVALID_HANDLE	The specified handle was not obtained using CreateService or OpenService, or the handle is no longer valid.
ERROR_INVALID_PARAMETER	The requested control code is undefined.
ERROR_INVALID_SERVICE_CONTROL	The requested control code is not valid, or it is unacceptable to the service.
ERROR_SERVICE_CANNOT_ACCEPT_CTRL	The requested control code cannot be sent to the service because the state of the service is SERVICE_STOPPED, SERVICE_START_PENDING, or SERVICE_STOP_PENDING.
ERROR_SERVICE_NOT_ACTIVE	The service has not been started.
ERROR_SERVICE_REQUEST_TIMEOUT	The process for the service was started, but it did not call StartServiceCtrlDispatcher, or the thread that called StartServiceCtrlDispatcher may be blocked in a control handler function.
ERROR_SHUTDOWN_IN_PROGRESS	The system is shutting down.

Remarks

The ControlService function asks the Service Control Manager (SCM) to send the requested control code to the service. The SCM sends the code if the service has specified that it will accept the code, and is in a state in which a control code can be sent to it.

The SCM processes service control notifications in a serial fashion — it will wait for one service to complete processing a service control notification before sending the next one. Because of this, a call to ControlService will block for 30 seconds if any service is busy handling a control code. If the busy service still has not returned from its handler function when the timeout expires, ControlService fails with ERROR_SERVICE_REQUEST_TIMEOUT.

To stop and start a service requires a security descriptor that allows you to do so. The default security descriptor allows the LocalSystem account, and members of the Administrators and Power Users groups to stop and start services. To change the security descriptor of a service, see Modifying the DACL for a Service.

The QueryServiceStatusEx function returns a SERVICE_STATUS_PROCESS structure whose dwCurrentState and dwControlsAccepted members indicate the current state and controls accepted by a running service. All running services accept the SERVICE_CONTROL_INTERROGATE control code by default. Drivers do not accept control codes other than SERVICE_CONTROL_STOP and SERVICE_CONTROL_INTERROGATE. Each service specifies the other control codes that it accepts when it calls the SetServiceStatus function to report its status. A service should always accept these codes when it is running, no matter what it is doing.

The following table shows the action of the SCM in each of the possible service states.

Service state	Stop	Other controls
STOPPED	(c)	(c)
STOP_PENDING	(b)	(b)
START_PENDING	(a)	(b)
RUNNING	(a)	(a)
CONTINUE_PENDING	(a)	(a)
PAUSE_PENDING	(a)	(a)
PAUSED	(a)	(a)

(a)

If the service accepts this control code, send the request to the service; otherwise, ControlService returns zero and GetLastError returns ERROR_INVALID_SERVICE_CONTROL.

(b)

The service is not in a state in which a control can be sent to it, so ControlService returns zero and GetLastError returns ERROR_SERVICE_CANNOT_ACCEPT_CTRL.

(c)

The service is not active, so ControlService returns zero and GetLastError returns ERROR_SERVICE_NOT_ACTIVE.

Example Code

For an example, see Sending Control Requests to a Service.

Requirements

Client	Requires Windows XP, Windows 2000 Professional, or Windows NT Workstation.
Server	Requires Windows Server 2003, Windows 2000 Server, or Windows NT Server.
Header	Declared in Winsvc.h; include Windows.h.
Library	Link to Advapi32.lib.
DLL	Requires Advapi32.dll.