Question

我正在编写一个创建Windows服务的C应用程序。我想在尝试调用安装功能之前检查服务是否已安装，但我无法找到如何检查它。

我已经编写了上面的代码来尝试：

DWORD InstallMyService()
{
    char strDir[1024 + 1];
    SC_HANDLE schSCManager;
    SC_HANDLE schService;
    LPCTSTR lpszBinaryPathName;

    if (GetCurrentDirectory(1024, strDir) == 0)
    {
        aff_error("GetCurrentDirectory");
        return FALSE;
    }
    strcat(strDir, "\\"MY_SERVICE_BIN_NAME);
    if ((schSCManager = OpenSCManager(NULL, NULL, SC_MANAGER_ALL_ACCESS)) == NULL)
    {
        printf("Error OpenSCManager : %d\n", GetLastError());
        return FALSE;
    }
    lpszBinaryPathName = strDir;
    schService = CreateService(schSCManager, MY_SERVICE_NAME, MY_SERVICE_DESCRIPTOR,
                             SERVICE_ALL_ACCESS, SERVICE_WIN32_OWN_PROCESS, SERVICE_AUTO_START, SERVICE_ERROR_NORMAL,
                             lpszBinaryPathName, NULL, NULL, NULL, NULL, NULL);
    if (schService == NULL)
    {
        printf("Error CreateService : %d\n", GetLastError());
        return FALSE;
    }
    CloseServiceHandle(schService);
    return TRUE;
}

但是此代码不会检测服务是否仍然存在。有人知道要调用哪个函数吗？我发现很多帖子都在谈论这个，但不是在C中，只在C＃或VB中。

谢谢。

Answer 1

可能会始终尝试CreateService()并且如果失败查询GetLastError()并检查它是否等于ERROR_SERVICE_EXISTS：

SC_HANDLE service_handle = CreateService(...);
if (0 == service_handle)
{
    if (ERROR_SERVICE_EXISTS == GetLastError())
    {
        /* Handle service already exists. */
    }
    else
    {
        /* Handle failure. */
    }
}

这需要对您的代码进行轻微更改，使两个函数InstallService()和CheckService()具有一个函数（例如）EnsureServiceInstalled()。

或者，您可以使用OpenService()函数，该函数将GetLastError() ERROR_SERVICE_DOES_NOT_EXIST代码失败：

SC_HANDLE scm_handle = OpenSCManager(0, 0, GENERIC_READ);

if (scm_handle)
{
    SC_HANDLE service_handle = OpenService(scm_handle,
                                           "the-name-of-your-service",
                                           GENERIC_READ);
    if (!service_handle)
    {
        if (ERROR_SERVICE_DOES_NOT_EXIST != GetLastError())
        {
            fprintf(stderr,
                    "Failed to OpenService(): %d\n",
                    GetLastError());
        }
        else
        {
            /* Service does not exist. */
            fprintf(stderr, "Service does not exist.\n");
        }
    }
    else
    {
        fprintf(stderr, "Opened service.\n");
        CloseServiceHandle(service_handle);
    }

    CloseServiceHandle(scm_handle);
}
else
{
    fprintf(stderr,
            "Failed to OpenSCManager(): %d\n",
            GetLastError());
}

Answer 2

如果您需要是/否答案是安装服务还是注释，请使用以下功能：

bool IsServiceInstalled(LPWSTR ServiceName)
{
    bool serviceInstalled = false;
    SC_HANDLE scm_handle = OpenSCManager(0, 0, SC_MANAGER_CONNECT);
    if (scm_handle)
    {
        SC_HANDLE service_handle = OpenService(scm_handle, ServiceName, SERVICE_INTERROGATE);
        if (service_handle != NULL)
        {
            wprintf(L"Service  Installed\n");
            serviceInstalled = true;
            CloseServiceHandle(service_handle);
        }
        else
        {
            wprintf(_T("OpenService failed - service not installed\n"));
        }
        CloseServiceHandle(scm_handle);
    }
    else
        wprintf(_T("OpenService couldn't open - service not installed\n"));

    return serviceInstalled;

}

Answer 3

尝试使用QueryServiceStatusEx

参见示例here

检查是否使用C安装了服务

3 个答案: