OpenSCManager

The OpenSCManager function establishes a connection to the service control manager on the specified computer and opens the specified service control manager database.

SC_HANDLE OpenSCManager(
  LPCTSTR lpMachineName,  // pointer to machine name string
  LPCTSTR lpDatabaseName,  // pointer to database name string
  DWORD dwDesiredAccess   // type of access
);

Parameters

lpMachineName

Pointer to a null-terminated string that names the target computer. If the pointer is NULL or points to an empty string, the function connects to the service control manager on the local computer.

lpDatabaseName

Pointer to a null-terminated string that names the service control manager database to open. This parameter should be set to SERVICES_ACTIVE_DATABASE. If it is NULL, the SERVICES_ACTIVE_DATABASE database is opened by default.

dwDesiredAccess

Specifies the access to the service control manager. 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 control manager. The SC_MANAGER_CONNECT access type is implicitly specified by calling this function. In addition, any or all of the following service control manager object access types can be specified:

Type	Description
SC_MANAGER_ALL_ACCESS
	Includes STANDARD_RIGHTS_REQUIRED, in addition to all of the access types listed in this table.
SC_MANAGER_CONNECT
	Enables connecting to the service control manager.
SC_MANAGER_CREATE_SERVICE
	Enables calling of the CreateService function to create a service object and add it to the database.
SC_MANAGER_ENUMERATE_SERVICE
	Enables calling of the EnumServicesStatus function to list the services that are in the database.
SC_MANAGER_LOCK
	Enables calling of the LockServiceDatabase function to acquire a lock on the database.
SC_MANAGER_QUERY_LOCK_STATUS
	Enables calling of the QueryServiceLockStatus function to retrieve the lock status information for the database.

The dwDesiredAccess parameter can specify any or all of the following generic access types:

Generic access Service manager access

GENERIC_READ Combines the following access types: STANDARD_RIGHTS_READ, SC_MANAGER_ENUMERATE_SERVICE, and SC_MANAGER_QUERY_LOCK_STATUS.

GENERIC_WRITE Combines the following access types: STANDARD_RIGHTS_WRITE and SC_MANAGER_CREATE_SERVICE.

GENERIC_EXECUTE Combines the following access types: STANDARD_RIGHTS_EXECUTE, SC_MANAGER_CONNECT, and SC_MANAGER_LOCK.

Generic access	Service manager access
GENERIC_READ	Combines the following access types: STANDARD_RIGHTS_READ, SC_MANAGER_ENUMERATE_SERVICE, and SC_MANAGER_QUERY_LOCK_STATUS.
GENERIC_WRITE	Combines the following access types: STANDARD_RIGHTS_WRITE and SC_MANAGER_CREATE_SERVICE.
GENERIC_EXECUTE	Combines the following access types: STANDARD_RIGHTS_EXECUTE, SC_MANAGER_CONNECT, and SC_MANAGER_LOCK.

Return Values

If the function succeeds, the return value is a handle to the specified service control manager database.

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 SCM. Other error codes can be set by the registry functions that are called by the SCM.

Error code	Meaning
ERROR_ACCESS_DENIED	The requested access was denied.
ERROR_DATABASE_DOES_NOT_EXIST	The specified database does not exist.
ERROR_INVALID_PARAMETER	A specified parameter is invalid.

Remarks

When a process uses the OpenSCManager function to open a handle to a service control manager database, the system performs a security check before granting the requested access. All processes are permitted SC_MANAGER_CONNECT, SC_MANAGER_ENUMERATE_SERVICE, and SC_MANAGER_QUERY_LOCK_STATUS access to all service control manager databases. This enables any process to open a service control manager database handle that it can use in the OpenService, EnumServicesStatus, and QueryServiceLockStatus functions. Only processes with Administrator privileges are able to open a database handle used by the CreateService and LockServiceDatabase functions.

The returned handle is only valid for the process that called the OpenSCManager function. It can be closed by calling the CloseServiceHandle function.

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