Memulai Layanan

Untuk memulai layanan, program kontrol layanan membuka handel ke database yang diinstal lalu menentukan handel dalam panggilan ke fungsi StartService . Setelah memulai layanan, program menggunakan anggota struktur SERVICE_STATUS_PROCESS yang dikembalikan oleh fungsi QueryServiceStatusEx untuk melacak kemajuan layanan.

Fungsi DoStartSvc dalam contoh berikut menunjukkan cara memulai layanan. Variabel szSvcName adalah variabel global yang berisi nama layanan yang akan dimulai. Untuk contoh lengkap yang mengatur variabel ini, lihat SvcControl.cpp.

//
// Purpose: 
//   Starts the service if possible.
//
// Parameters:
//   None
// 
// Return value:
//   None
//
VOID __stdcall DoStartSvc()
{
    SERVICE_STATUS_PROCESS ssStatus; 
    DWORD dwOldCheckPoint; 
    DWORD dwStartTickCount;
    DWORD dwWaitTime;
    DWORD dwBytesNeeded;

    // Get a handle to the SCM database. 
 
    schSCManager = OpenSCManager( 
        NULL,                    // local computer
        NULL,                    // servicesActive database 
        SC_MANAGER_ALL_ACCESS);  // full access rights 
 
    if (NULL == schSCManager) 
    {
        printf("OpenSCManager failed (%d)\n", GetLastError());
        return;
    }

    // Get a handle to the service.

    schService = OpenService( 
        schSCManager,         // SCM database 
        szSvcName,            // name of service 
        SERVICE_ALL_ACCESS);  // full access 
 
    if (schService == NULL)
    { 
        printf("OpenService failed (%d)\n", GetLastError()); 
        CloseServiceHandle(schSCManager);
        return;
    }    

    // Check the status in case the service is not stopped. 

    if (!QueryServiceStatusEx( 
            schService,                     // handle to service 
            SC_STATUS_PROCESS_INFO,         // information level
            (LPBYTE) &ssStatus,             // address of structure
            sizeof(SERVICE_STATUS_PROCESS), // size of structure
            &dwBytesNeeded ) )              // size needed if buffer is too small
    {
        printf("QueryServiceStatusEx failed (%d)\n", GetLastError());
        CloseServiceHandle(schService); 
        CloseServiceHandle(schSCManager);
        return; 
    }

    // Check if the service is already running. It would be possible 
    // to stop the service here, but for simplicity this example just returns. 

    if(ssStatus.dwCurrentState != SERVICE_STOPPED && ssStatus.dwCurrentState != SERVICE_STOP_PENDING)
    {
        printf("Cannot start the service because it is already running\n");
        CloseServiceHandle(schService); 
        CloseServiceHandle(schSCManager);
        return; 
    }

    // Save the tick count and initial checkpoint.

    dwStartTickCount = GetTickCount();
    dwOldCheckPoint = ssStatus.dwCheckPoint;

    // Wait for the service to stop before attempting to start it.

    while (ssStatus.dwCurrentState == SERVICE_STOP_PENDING)
    {
        // Do not wait longer than the wait hint. A good interval is 
        // one-tenth of the wait hint but not less than 1 second  
        // and not more than 10 seconds. 
 
        dwWaitTime = ssStatus.dwWaitHint / 10;

        if( dwWaitTime < 1000 )
            dwWaitTime = 1000;
        else if ( dwWaitTime > 10000 )
            dwWaitTime = 10000;

        Sleep( dwWaitTime );

        // Check the status until the service is no longer stop pending. 
 
        if (!QueryServiceStatusEx( 
                schService,                     // handle to service 
                SC_STATUS_PROCESS_INFO,         // information level
                (LPBYTE) &ssStatus,             // address of structure
                sizeof(SERVICE_STATUS_PROCESS), // size of structure
                &dwBytesNeeded ) )              // size needed if buffer is too small
        {
            printf("QueryServiceStatusEx failed (%d)\n", GetLastError());
            CloseServiceHandle(schService); 
            CloseServiceHandle(schSCManager);
            return; 
        }

        if ( ssStatus.dwCheckPoint > dwOldCheckPoint )
        {
            // Continue to wait and check.

            dwStartTickCount = GetTickCount();
            dwOldCheckPoint = ssStatus.dwCheckPoint;
        }
        else
        {
            if(GetTickCount()-dwStartTickCount > ssStatus.dwWaitHint)
            {
                printf("Timeout waiting for service to stop\n");
                CloseServiceHandle(schService); 
                CloseServiceHandle(schSCManager);
                return; 
            }
        }
    }

    // Attempt to start the service.

    if (!StartService(
            schService,  // handle to service 
            0,           // number of arguments 
            NULL) )      // no arguments 
    {
        printf("StartService failed (%d)\n", GetLastError());
        CloseServiceHandle(schService); 
        CloseServiceHandle(schSCManager);
        return; 
    }
    else printf("Service start pending...\n"); 

    // Check the status until the service is no longer start pending. 
 
    if (!QueryServiceStatusEx( 
            schService,                     // handle to service 
            SC_STATUS_PROCESS_INFO,         // info level
            (LPBYTE) &ssStatus,             // address of structure
            sizeof(SERVICE_STATUS_PROCESS), // size of structure
            &dwBytesNeeded ) )              // if buffer too small
    {
        printf("QueryServiceStatusEx failed (%d)\n", GetLastError());
        CloseServiceHandle(schService); 
        CloseServiceHandle(schSCManager);
        return; 
    }
 
    // Save the tick count and initial checkpoint.

    dwStartTickCount = GetTickCount();
    dwOldCheckPoint = ssStatus.dwCheckPoint;

    while (ssStatus.dwCurrentState == SERVICE_START_PENDING) 
    { 
        // Do not wait longer than the wait hint. A good interval is 
        // one-tenth the wait hint, but no less than 1 second and no 
        // more than 10 seconds. 
 
        dwWaitTime = ssStatus.dwWaitHint / 10;

        if( dwWaitTime < 1000 )
            dwWaitTime = 1000;
        else if ( dwWaitTime > 10000 )
            dwWaitTime = 10000;

        Sleep( dwWaitTime );

        // Check the status again. 
 
        if (!QueryServiceStatusEx( 
            schService,             // handle to service 
            SC_STATUS_PROCESS_INFO, // info level
            (LPBYTE) &ssStatus,             // address of structure
            sizeof(SERVICE_STATUS_PROCESS), // size of structure
            &dwBytesNeeded ) )              // if buffer too small
        {
            printf("QueryServiceStatusEx failed (%d)\n", GetLastError());
            break; 
        }
 
        if ( ssStatus.dwCheckPoint > dwOldCheckPoint )
        {
            // Continue to wait and check.

            dwStartTickCount = GetTickCount();
            dwOldCheckPoint = ssStatus.dwCheckPoint;
        }
        else
        {
            if(GetTickCount()-dwStartTickCount > ssStatus.dwWaitHint)
            {
                // No progress made within the wait hint.
                break;
            }
        }
    } 

    // Determine whether the service is running.

    if (ssStatus.dwCurrentState == SERVICE_RUNNING) 
    {
        printf("Service started successfully.\n"); 
    }
    else 
    { 
        printf("Service not started. \n");
        printf("  Current State: %d\n", ssStatus.dwCurrentState); 
        printf("  Exit Code: %d\n", ssStatus.dwWin32ExitCode); 
        printf("  Check Point: %d\n", ssStatus.dwCheckPoint); 
        printf("  Wait Hint: %d\n", ssStatus.dwWaitHint); 
    } 

    CloseServiceHandle(schService); 
    CloseServiceHandle(schSCManager);
}

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