OpenService
The OpenService
function opens a handle to an existing service.
SC_HANDLE OpenService(
|
SC_HANDLE hSCManager, |
// handle to
service control manager database |
|
LPCTSTR lpServiceName, |
// pointer to name
of service to start |
|
DWORD dwDesiredAccess |
// type of access
to service |
|
); |
|
Parameters
hSCManager
Identifies
the service control manager (SCM) database. The OpenSCManager function returns this
handle.
lpServiceName
Points to a
null-terminated string that names the service to open. The maximum string
length is 256 characters. The SCM database preserves the case of the
characters, but service name comparisons are always case insensitive. A slash
(/), backslash (\), comma, and space are invalid service name characters.
dwDesiredAccess
Specifies the
access to the service. Before granting the requested access, the system checks
the access token of the calling process against the discretionary
access-control list of the security descriptor associated with the service
object. Any or all of the following service object access types can be
specified:
|
Access |
Description |
|
SERVICE_ALL_ACCESS |
Includes
STANDARD_RIGHTS_REQUIRED in addition to all of the access types listed in
this table. |
|
SERVICE_CHANGE_CONFIG |
Enables
calling of the ChangeServiceConfig function to change the service
configuration. |
|
SERVICE_ENUMERATE_DEPENDENTS |
Enables
calling of the EnumDependentServices function to enumerate all the services
dependent on the service. |
|
SERVICE_INTERROGATE |
Enables
calling of the ControlService function to ask the service to report its status
immediately. |
|
SERVICE_PAUSE_CONTINUE |
Enables
calling of the ControlService function to pause or continue the
service. |
|
SERVICE_QUERY_CONFIG |
Enables
calling of the QueryServiceConfig function to query the service configuration. |
|
SERVICE_QUERY_STATUS |
Enables calling
of the QueryServiceStatus function to ask the service control manager
about the status of the service. |
|
SERVICE_START |
Enables
calling of the StartService
function to start the service. |
|
SERVICE_STOP |
Enables
calling of the ControlService function to stop the service. |
|
SERVICE_USER_DEFINED_CONTROL |
Enables
calling of the ControlService function to specify a user-defined
control code. |
STANDARD_RIGHTS_REQUIRED
enables the following service object access types:
|
Standard
rights |
Description |
|
DELETE |
Enables
calling of the DeleteService function to delete the service. |
|
READ_CONTROL |
Enables
calling of the QueryServiceObjectSecurity function to query the security descriptor of
the service object. |
|
WRITE_DAC|WRITE_OWNER |
Enables
calling of the SetServiceObjectSecurity function to modify the security descriptor of
the service object. |
The dwDesiredAccess
parameter can specify any or all of the following generic access types:
|
Generic
access |
Service
access |
|
GENERIC_READ |
Combines
the following access: STANDARD_RIGHTS_READ, SERVICE_QUERY_CONFIG,
SERVICE_QUERY_STATUS, SERVICE_INTERROGATE, and SERVICE_ENUMERATE_DEPENDENTS. |
|
GENERIC_WRITE |
Combines
the following access: STANDARD_RIGHTS_WRITE and SERVICE_CHANGE_CONFIG. |
|
GENERIC_EXECUTE |
Combines
the following access: STANDARD_RIGHTS_EXECUTE, SERVICE_START, SERVICE_STOP,
SERVICE_PAUSE_CONTINUE, and SERVICE_USER_DEFINED_CONTROL. |
Return Values
If the
function succeeds, the return value is a handle to the service.
If the
function fails, the return value is NULL. To get extended error information,
call GetLastError.
Errors
The following
error codes can be set by the service control manager. Others can be set by the
registry functions that are called by the service control manager.
|
Error code |
Meaning |
|
ERROR_ACCESS_DENIED |
The
specified service control manager database handle does not have access to the
service. |
|
ERROR_INVALID_HANDLE |
The
specified handle is invalid. |
|
ERROR_INVALID_NAME |
The
specified service name is invalid. |
|
ERROR_SERVICE_DOES_NOT_EXIST |
The
specified service does not exist. |
Remarks
The calling
process can use the returned handle to identify the service in the following
functions, if the appropriate access rights are enabled:
ChangeServiceConfig
ControlService
DeleteService
EnumDependentServices
QueryServiceConfig
QueryServiceObjectSecurity
QueryServiceStatus
SetServiceObjectSecurity
StartService
The returned
handle is only valid for the process that called OpenService. It can be
closed by calling the CloseServiceHandle function.
See Also