gpolicy.c

这是一个开放源代码的与WINNT/WIN2K/WIN2003兼容的操作系统

/*
 *  ReactOS kernel
 *  Copyright (C) 2006 ReactOS Team
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
/*
 * COPYRIGHT:       See COPYING in the top level directory
 * PROJECT:         ReactOS system libraries
 * FILE:            lib/userenv/gpolicy.c
 * PURPOSE:         Group policy functions
 * PROGRAMMER:      Thomas Weidenmueller <[e-mail]>
 */

#include <precomp.h>

#define NDEBUG
#include <debug.h>


typedef struct _GP_NOTIFY
{
    struct _GP_NOTIFY *Next;
    HANDLE hEvent;
    BOOL bMachine;
} GP_NOTIFY, *PGP_NOTIFY;

typedef enum
{
    gpaUpdate = 0,
    gpaTerminate
} GP_ACTION;

static const WCHAR szLocalGPApplied[] = L"userenv: User Group Policy has been applied";
static const WCHAR szLocalGPMutex[] = L"userenv: user policy mutex";
static const WCHAR szLocalGPRefreshEvent[] = L"userenv: user policy refresh event";
static const WCHAR szLocalGPForceRefreshEvent[] = L"userenv: user policy force refresh event";
static const WCHAR szLocalGPDoneEvent[] = L"userenv: User Policy Foreground Done Event";
static const WCHAR szMachineGPApplied[] = L"Global\\userenv: Machine Group Policy has been applied";
static const WCHAR szMachineGPMutex[] = L"Global\\userenv: machine policy mutex";
static const WCHAR szMachineGPRefreshEvent[] = L"Global\\userenv: machine policy refresh event";
static const WCHAR szMachineGPForceRefreshEvent[] = L"Global\\userenv: machine policy force refresh event";
static const WCHAR szMachineGPDoneEvent[] = L"Global\\userenv: Machine Policy Foreground Done Event";

static CRITICAL_SECTION GPNotifyLock;
static PGP_NOTIFY NotificationList = NULL;
static GP_ACTION GPNotificationAction = gpaUpdate;
static HANDLE hNotificationThread = NULL;
static HANDLE hNotificationThreadEvent = NULL;
static HANDLE hLocalGPAppliedEvent = NULL;
static HANDLE hMachineGPAppliedEvent = NULL;

VOID
InitializeGPNotifications(VOID)
{
    InitializeCriticalSection(&GPNotifyLock);
}

VOID
UninitializeGPNotifications(VOID)
{
    EnterCriticalSection(&GPNotifyLock);

    /* rundown the notification thread */
    if (hNotificationThread != NULL)
    {
        ASSERT(hNotificationThreadEvent != NULL);

        /* notify the thread */
        GPNotificationAction = gpaTerminate;
        SetEvent(hNotificationThreadEvent);

        LeaveCriticalSection(&GPNotifyLock);

        /* wait for the thread to terminate itself */
        WaitForSingleObject(hNotificationThread,
                            INFINITE);

        EnterCriticalSection(&GPNotifyLock);

        if (hNotificationThread != NULL)
        {
            /* the handle should be closed by the thread,
               just in case that didn't happen for an unknown reason */
            CloseHandle(hNotificationThread);
            hNotificationThread = NULL;
        }
    }

    if (hNotificationThreadEvent != NULL)
    {
        CloseHandle(hNotificationThreadEvent);
        hNotificationThreadEvent = NULL;
    }

    LeaveCriticalSection(&GPNotifyLock);

    DeleteCriticalSection(&GPNotifyLock);
}

static VOID
NotifyGPEvents(IN BOOL bMachine)
{
    PGP_NOTIFY Notify = NotificationList;

    while (Notify != NULL)
    {
        if (Notify->bMachine == bMachine)
        {
            SetEvent(Notify->hEvent);
        }

        Notify = Notify->Next;
    }
}

static DWORD WINAPI
GPNotificationThreadProc(IN LPVOID lpParameter)
{
    HMODULE hModule;
    DWORD WaitResult, WaitCount;
    HANDLE WaitHandles[3];

    /* reference the library so we don't screw up if the application
       causes the DLL to unload while this thread is still running */
    if (GetModuleHandleExW(GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS,
                           (LPCWSTR)hInstance,
                           &hModule))
    {
        ASSERT(hModule == hInstance);

        EnterCriticalSection(&GPNotifyLock);

        ASSERT(hNotificationThreadEvent != NULL);
        WaitHandles[0] = hNotificationThreadEvent;
        for (;;)
        {
            ASSERT(hMachineGPAppliedEvent != NULL);

            if (NotificationList == NULL)
                break;

            WaitCount = 2;
            WaitHandles[1] = hMachineGPAppliedEvent;

            if (hLocalGPAppliedEvent != NULL)
            {
                WaitHandles[2] = hLocalGPAppliedEvent;
                WaitCount++;
            }

            LeaveCriticalSection(&GPNotifyLock);

            WaitResult = WaitForMultipleObjects(WaitCount,
                                                WaitHandles,
                                                FALSE,
                                                INFINITE);

            EnterCriticalSection(&GPNotifyLock);

            if (WaitResult != WAIT_FAILED)
            {
                if (WaitResult == WAIT_OBJECT_0)
                {
                    ResetEvent(hNotificationThreadEvent);

                    if (GPNotificationAction == gpaTerminate)
                    {
                        /* terminate the thread */
                        break;
                    }
                }
                else if (WaitResult == WAIT_OBJECT_0 + 1 || WaitResult == WAIT_OBJECT_0 + 2)
                {
                    /* group policies have been applied */
                    if (NotificationList != NULL)
                    {
                        NotifyGPEvents((WaitResult == WAIT_OBJECT_0 + 1));
                    }
                }
                else if (WaitResult == WAIT_ABANDONED_0 + 2)
                {
                    /* In case the local group policies event was abandoned, keep watching!
                       But close the handle as it's no longer of any use. */
                    if (hLocalGPAppliedEvent != NULL)
                    {
                        CloseHandle(hLocalGPAppliedEvent);
                        hLocalGPAppliedEvent = NULL;
                    }
                }
                else if (WaitResult == WAIT_ABANDONED_0 || WaitResult == WAIT_ABANDONED_0 + 1)
                {
                    /* terminate the thread if the machine group policies event was abandoned
                       or for some reason the rundown event got abandoned. */
                    break;
                }
                else
                {
                    DPRINT("Unexpected wait result watching the group policy events: 0x%x\n", WaitResult);
                    ASSERT(FALSE);
                    break;
                }

                if (NotificationList == NULL)
                    break;
            }
            else
                break;

        }

        /* cleanup handles no longer used */
        ASSERT(hNotificationThread != NULL);
        ASSERT(hNotificationThreadEvent != NULL);

        CloseHandle(hNotificationThread);
        CloseHandle(hNotificationThreadEvent);
        hNotificationThread = NULL;
        hNotificationThreadEvent = NULL;

        if (hLocalGPAppliedEvent != NULL)
        {
            CloseHandle(hLocalGPAppliedEvent);
            hLocalGPAppliedEvent = NULL;
        }
        if (hMachineGPAppliedEvent != NULL)
        {
            CloseHandle(hMachineGPAppliedEvent);
            hMachineGPAppliedEvent = NULL;
        }

        LeaveCriticalSection(&GPNotifyLock);

        /* dereference the library and exit */
        FreeLibraryAndExitThread(hModule,
                                 0);
    }
    else
    {
        DPRINT1("Referencing the library failed!\n");
    }

    return 1;
}

static HANDLE
CreateGPEvent(IN BOOL bMachine,
              IN PSECURITY_DESCRIPTOR lpSecurityDescriptor)
{
    HANDLE hEvent;
    SECURITY_ATTRIBUTES SecurityAttributes;

    SecurityAttributes.nLength = sizeof(SECURITY_ATTRIBUTES);
    SecurityAttributes.lpSecurityDescriptor = lpSecurityDescriptor;
    SecurityAttributes.bInheritHandle = FALSE;

    hEvent = CreateEventW(&SecurityAttributes,
                          TRUE,
                          FALSE,
                          (bMachine ? szMachineGPApplied : szLocalGPApplied));

    return hEvent;
}

BOOL WINAPI
RegisterGPNotification(IN HANDLE hEvent,
                       IN BOOL bMachine)
{
    PGP_NOTIFY Notify;
    PSECURITY_DESCRIPTOR lpSecurityDescriptor = NULL;