CODEWITHSUNDEEP
cwindowsdebuggingwindows-servicesstartup
Eric
Eric

Reputation: 305

how to debug windows service start-up code in c,not c#

everyone

I want to know how to debug the windows service start-up code in C.there are several questions like this but in C# but they are not what I need. So far,I can only attach to process to debug.Now I want to debug the main() function,how to do? The more detailed,the better.

Thanks so much.

My codes are below.

main function:

void main()
{   
    SERVICE_TABLE_ENTRY ServiceTable[2];
    ServiceTable[0].lpServiceName = "MemoryStatus";  
    ServiceTable[0].lpServiceProc = (LPSERVICE_MAIN_FUNCTION)ServiceMain; //ServiceMain
    ServiceTable[1].lpServiceName = NULL;
    ServiceTable[1].lpServiceProc = NULL;

    StartServiceCtrlDispatcher(ServiceTable);
}

ServiceMain Function:

void ServiceMain(int argc, char** argv)
{        
    //...some codes....

    hStatus = RegisterServiceCtrlHandler("MemoryStatus",(LPHANDLER_FUNCTION)ControlHandler);

    //...some codes....

    //the worker loop of a service
    while(ServiceStatus.dwCurrentState == SERVICE_RUNNING)
    {
        char buffer[10];        
        sprintf(buffer,"login...");
        int result = WriteToLog(buffer);        
        if (result)
        {
             ReportStatus(SERVICE_STOPPED,-1);
             return;
        }
        Sleep(SLEEP_TIME);
    }
    return;
}

and control handle function:

void ControlHandler(DWORD request)
{
    switch(request)
    {
    case SERVICE_CONTROL_STOP:
        WriteToLog("Monitoring stopped.");
        //...Report Status to SCM code....
        return;
    case SERVICE_CONTROL_SHUTDOWN:
        WriteToLog("Monitoring stopped.");
        //...Report Status to SCM code....
        return;
    default:
        break;
    }
//...Report Status to SCM code....
    return;
}

Upvotes: 1

Views: 1296

Answers (2)

Eric
Eric

Reputation: 305

OK,two ways: First,we can sleep the service process at the beginning of code. like this:

main()
{
    sleep(10);
    .....
}

and then attach to the service process, the debugger will stop at the position of breakpoint as we have 10 seconds to wait.

Second,we can use _ASSERT(FALSE) or DebugBreak() function at the beginning of code.

Upvotes: 0

Sebastian
Sebastian

Reputation: 3864

There are two different ways to debug a windows service from its start. Both are described here.

My preferred one consists of using a remote debugger session that starts with a service (you may use ntsd from Windows Debugging Tool). There is a special mechanism in Windows that enables you to hijack a process based on its image name (Image File Execution Options). Below you can find a content of a .reg file that will setup this debugger for you (change the path to the one where you have Debugging tools installed):

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\svchost.exe]
"Debugger"="\"C:\\tools\\debugging\\Debugging Tools for Windows (x64)\\ntsd.exe\" -server npipe:pipe=svcpipe -noio"

Next step would be to attach to this session using user-mode debugger:

windbg -remote "npipe:pipe=svcpipe,server=localhost"

and you are ready to debug. Remember to remove the registry settings before you reboot your machine, otherwise windows will hang with a black screen :)

Upvotes: 2

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