How do I write to a log file from a Windows Service - c++

Question

I have a windows service. All I want to do right now is see what it is doing and ensure it is working. Unfortunately, I can't write to the file system and OutputDebugString does not work.
#include "stdafx.h"
SERVICE_STATUS g_ServiceStatus = {0};
SERVICE_STATUS_HANDLE g_StatusHandle = NULL;
HANDLE g_ServiceStopEvent = INVALID_HANDLE_VALUE;
void Log(char * text)
{
FILE * f = fopen("TestSocketServiceLog.txt", "a+");
fprintf(f, "%s\n", text);
fclose(f);
}
VOID WINAPI ServiceMain (DWORD argc, LPTSTR *argv);
VOID WINAPI ServiceCtrlHandler (DWORD);
DWORD WINAPI ServiceWorkerThread (LPVOID lpParam);
#define SERVICE_NAME _T("TestSocketService")
int _tmain (int argc, TCHAR *argv[])
{
OutputDebugString(_T("TestSocketService: Main: Entry"));
SERVICE_TABLE_ENTRY ServiceTable[] =
{
{SERVICE_NAME, (LPSERVICE_MAIN_FUNCTION) ServiceMain},
{NULL, NULL}
};
if (StartServiceCtrlDispatcher (ServiceTable) == FALSE)
{
OutputDebugString(_T("TestSocketService: Main: StartServiceCtrlDispatcher returned error\n"));
return GetLastError ();
}
OutputDebugString(_T("TestSocketService: Main: Exit"));
return 0;
}
VOID WINAPI ServiceMain (DWORD argc, LPTSTR *argv)
{
DWORD Status = E_FAIL;
OutputDebugString(_T("TestSocketService: ServiceMain: Entry"));
g_StatusHandle = RegisterServiceCtrlHandler (SERVICE_NAME, ServiceCtrlHandler);
if (g_StatusHandle == NULL)
{
OutputDebugString(_T("TestSocketService: ServiceMain: RegisterServiceCtrlHandler returned error"));
goto EXIT;
}
// Tell the service controller we are starting
ZeroMemory (&g_ServiceStatus, sizeof (g_ServiceStatus));
g_ServiceStatus.dwServiceType = SERVICE_WIN32_OWN_PROCESS;
g_ServiceStatus.dwControlsAccepted = 0;
g_ServiceStatus.dwCurrentState = SERVICE_START_PENDING;
g_ServiceStatus.dwWin32ExitCode = 0;
g_ServiceStatus.dwServiceSpecificExitCode = 0;
g_ServiceStatus.dwCheckPoint = 0;
if (SetServiceStatus (g_StatusHandle, &g_ServiceStatus) == FALSE)
{
OutputDebugString(_T("TestSocketService: ServiceMain: SetServiceStatus returned error"));
}
/*
* Perform tasks neccesary to start the service here
*/
OutputDebugString(_T("TestSocketService: ServiceMain: Performing Service Start Operations"));
// Create stop event to wait on later.
g_ServiceStopEvent = CreateEvent (NULL, TRUE, FALSE, NULL);
if (g_ServiceStopEvent == NULL)
{
OutputDebugString(_T("TestSocketService: ServiceMain: CreateEvent(g_ServiceStopEvent) returned error"));
g_ServiceStatus.dwControlsAccepted = 0;
g_ServiceStatus.dwCurrentState = SERVICE_STOPPED;
g_ServiceStatus.dwWin32ExitCode = GetLastError();
g_ServiceStatus.dwCheckPoint = 1;
if (SetServiceStatus (g_StatusHandle, &g_ServiceStatus) == FALSE)
{
OutputDebugString(_T("TestSocketService: ServiceMain: SetServiceStatus returned error"));
}
goto EXIT;
}
// Tell the service controller we are started
g_ServiceStatus.dwControlsAccepted = SERVICE_ACCEPT_STOP;
g_ServiceStatus.dwCurrentState = SERVICE_RUNNING;
g_ServiceStatus.dwWin32ExitCode = 0;
g_ServiceStatus.dwCheckPoint = 0;
if (SetServiceStatus (g_StatusHandle, &g_ServiceStatus) == FALSE)
{
OutputDebugString(_T("TestSocketService: ServiceMain: SetServiceStatus returned error"));
}
// Start the thread that will perform the main task of the service
HANDLE hThread = CreateThread (NULL, 0, ServiceWorkerThread, NULL, 0, NULL);
OutputDebugString(_T("TestSocketService: ServiceMain: Waiting for Worker Thread to complete"));
// Wait until our worker thread exits effectively signaling that the service needs to stop
WaitForSingleObject (hThread, INFINITE);
OutputDebugString(_T("TestSocketService: ServiceMain: Worker Thread Stop Event signaled"));
/*
* Perform any cleanup tasks
*/
OutputDebugString(_T("TestSocketService: ServiceMain: Performing Cleanup Operations"));
CloseHandle (g_ServiceStopEvent);
g_ServiceStatus.dwControlsAccepted = 0;
g_ServiceStatus.dwCurrentState = SERVICE_STOPPED;
g_ServiceStatus.dwWin32ExitCode = 0;
g_ServiceStatus.dwCheckPoint = 3;
if (SetServiceStatus (g_StatusHandle, &g_ServiceStatus) == FALSE)
{
OutputDebugString(_T("TestSocketService: ServiceMain: SetServiceStatus returned error"));
}
EXIT:
OutputDebugString(_T("TestSocketService: ServiceMain: Exit"));
return;
}
VOID WINAPI ServiceCtrlHandler (DWORD CtrlCode)
{
OutputDebugString(_T("TestSocketService: ServiceCtrlHandler: Entry"));
switch (CtrlCode)
{
case SERVICE_CONTROL_STOP :
OutputDebugString(_T("TestSocketService: ServiceCtrlHandler: SERVICE_CONTROL_STOP Request"));
if (g_ServiceStatus.dwCurrentState != SERVICE_RUNNING)
break;
/*
* Perform tasks neccesary to stop the service here
*/
g_ServiceStatus.dwControlsAccepted = 0;
g_ServiceStatus.dwCurrentState = SERVICE_STOP_PENDING;
g_ServiceStatus.dwWin32ExitCode = 0;
g_ServiceStatus.dwCheckPoint = 4;
if (SetServiceStatus (g_StatusHandle, &g_ServiceStatus) == FALSE)
{
OutputDebugString(_T("TestSocketService: ServiceCtrlHandler: SetServiceStatus returned error"));
}
// This will signal the worker thread to start shutting down
SetEvent (g_ServiceStopEvent);
break;
default:
break;
}
OutputDebugString(_T("TestSocketService: ServiceCtrlHandler: Exit"));
}
DWORD WINAPI ServiceWorkerThread (LPVOID lpParam)
{
OutputDebugString(_T("TestSocketService: ServiceWorkerThread: Entry"));
// Periodically check if the service has been requested to stop
while (WaitForSingleObject(g_ServiceStopEvent, 0) != WAIT_OBJECT_0)
{
/*
* Perform main service function here
*/
// Simulate some work by sleeping
Sleep(3000);
}
OutputDebugString(_T("TestSocketService: ServiceWorkerThread: Exit"));
return ERROR_SUCCESS;
}
I tried using the function Log() located near the top of the program. The file "TestSocketServiceLog.txt" never showed up. And I tried using OutputDebugString(). None of the lines showed up in Debug View. I just want to see what the service is doing! What do I have to do to be able to get some kind of logging?