3. Algorithm of the client program
Fig. 3.1 - Algorithm of Client Program
The client program requests the data from user, check it, send it to service via named channels – pipes, and reads a reply from service.
The algorithm of client program is following:
Wait user input
Waits user.
Create file
Creates file via CreateFile function.
. Modify file to pipe
Calls SetNamedPipeHandleState for created file with PIPE_READMODE_MESSAGE parameter.
Get User data
Reads data from user.
Write data to pipe, flush buffers
Writes data to pipe via WriteFile function, and calls FlushBuffers function.
. Read reply from service
Reads reply from service from pipe.
Close pipe
Calls CloseHandler for pipe handler.
4. Implementation of service program
StartServiceCtrlDispatcher - connects the main thread of a service process to the service control manager, which causes the thread to be the service control dispatcher thread for the calling process [msdn].
RegisterServiceCtrlHandler - function to register a function to handle its service control requests [msdn].
SetSystemTime - sets the current system time and date [msdn].
CreateNamedPipe - creates an instance of a named pipe and returns a handle for subsequent pipe operations [msdn].
SetServiceStatus - updates the service control manager's status information for the calling service [msdn].
CreateEvent - creates or opens a named or unnamed event object [msdn].
WaitForSingleObject - returns when the specified object is in the signaled state or the time-out interval elapses [msdn].
WriteFile - writes data to a file at the position specified by the file pointer. This function is designed for both synchronous and asynchronous operation. [msdn].
ReadFile - reads data from a file, starting at the position that the file pointer indicates. [msdn].
CloseHandle - closes an open object handle [msdn].
ResetEvent - sets the specified event object to the no signaled state [msdn].
SetEvent - sets the specified event object to the signaled state [msdn].
SetServiceStatus - updates the service control manager's status information for the calling service [msdn].
ServiceControlHandler – function to control service run-time [msdn].
StartServiceq – service main function [msdn].
_tmain – funtion, that calls StartServiceCtrlDispatcher() for service [msdn].
5. Implementation of service management program
OpenSCManager - establishes a connection to the service control manager on the specified computer and opens the specified service control manager database [msdn].
CreateService - creates a service object and adds it to the specified service control manager database [msdn].
CloseServiceHandle - closes a handle to a service control manager or service object [msdn].
QueryServiceStatus - retrieves the current status of the specified service [msdn].
ControlService - sends a control code to a service [msdn].
StartService - starts a service [msdn].
QueryServiceConfig - retrieves the configuration parameters of the specified service [msdn].
ChangeServiceConfig - changes the configuration parameters of a service [msdn].
_tmain – interacts with user.