/*
 * COPYRIGHT:        See COPYING in the top level directory
 * PROJECT:          ReactOS Win32k subsystem
 * PURPOSE:          Shutdown routines
 * FILE:             win32ss/user/ntuser/shutdown.c
 * PROGRAMER:        Hermes Belusca
 */

#include <win32k.h>

DBG_DEFAULT_CHANNEL(UserShutdown);

/* Our local copy of shutdown flags */
static ULONG gdwShutdownFlags = 0;

/*
 * Based on CSRSS and described in pages 1115 - 1118 "Windows Internals, Fifth Edition".
 * CSRSS sends WM_CLIENTSHUTDOWN messages to top-level windows, and it is our job
 * to send WM_QUERYENDSESSION / WM_ENDSESSION messages in response.
 */
LRESULT
IntClientShutdown(IN PWND pWindow,
                  IN WPARAM wParam,
                  IN LPARAM lParam)
{
    LPARAM lParams;
    BOOL KillTimers;
    INT i;
    LRESULT lResult = MCSR_GOODFORSHUTDOWN;
    HWND *List;

    KillTimers = wParam & MCS_ENDSESSION ? TRUE : FALSE;
    lParams = lParam & (ENDSESSION_LOGOFF | ENDSESSION_CRITICAL | ENDSESSION_CLOSEAPP);

    /* First, send end sessions to children */
    List = IntWinListChildren(pWindow);

    if (List)
    {
        for (i = 0; List[i]; i++)
        {
            PWND WndChild;

            if (!(WndChild = UserGetWindowObject(List[i])))
                continue;

            if (wParam & MCS_QUERYENDSESSION)
            {
                if (!co_IntSendMessage(WndChild->head.h, WM_QUERYENDSESSION, 0, lParams))
                {
                    lResult = MCSR_DONOTSHUTDOWN;
                    break;
                }
            }
            else
            {
                co_IntSendMessage(WndChild->head.h, WM_ENDSESSION, KillTimers, lParams);
                if (KillTimers)
                {
                    DestroyTimersForWindow(WndChild->head.pti, WndChild);
                }
                lResult = MCSR_SHUTDOWNFINISHED;
            }
        }
        ExFreePoolWithTag(List, USERTAG_WINDOWLIST);
        if (lResult == MCSR_DONOTSHUTDOWN)
            return lResult;
    }

    /* Send to the caller */
    if (wParam & MCS_QUERYENDSESSION)
    {
        if (!co_IntSendMessage(pWindow->head.h, WM_QUERYENDSESSION, 0, lParams))
        {
            lResult = MCSR_DONOTSHUTDOWN;
        }
    }
    else
    {
        co_IntSendMessage(pWindow->head.h, WM_ENDSESSION, KillTimers, lParams);
        if (KillTimers)
        {
            DestroyTimersForWindow(pWindow->head.pti, pWindow);
        }
        lResult = MCSR_SHUTDOWNFINISHED;
    }

    return lResult;
}

BOOLEAN
HasPrivilege(IN PPRIVILEGE_SET Privilege)
{
    BOOLEAN Result;
    SECURITY_SUBJECT_CONTEXT SubjectContext;

    /* Capture and lock the security subject context */
    SeCaptureSubjectContext(&SubjectContext);
    SeLockSubjectContext(&SubjectContext);

    /* Do privilege check */
    Result = SePrivilegeCheck(Privilege, &SubjectContext, UserMode);

    /* Audit the privilege */
#if 0
    SePrivilegeObjectAuditAlarm(NULL,
                                &SubjectContext,
                                0,
                                Privilege,
                                Result,
                                UserMode);
#endif

    /* Unlock and release the security subject context and return */
    SeUnlockSubjectContext(&SubjectContext);
    SeReleaseSubjectContext(&SubjectContext);
    return Result;
}

BOOL
NotifyLogon(IN HWND hWndSta,
            IN PLUID CallerLuid,
            IN ULONG Flags,
            IN NTSTATUS ShutdownStatus)
{
    // LUID SystemLuid = SYSTEM_LUID;
    ULONG Notif, Param;

    ERR("NotifyLogon(0x%lx, 0x%lx)\n", Flags, ShutdownStatus);

    /* If no Winlogon notifications are needed, just return */
    if (Flags & EWX_NONOTIFY)
        return FALSE;

    /* In case we cancelled the shutdown...*/
    if (Flags & EWX_SHUTDOWN_CANCELED)
    {
        /* ... send a LN_LOGOFF_CANCELED to Winlogon with the real cancel status... */
        Notif = LN_LOGOFF_CANCELED;
        Param = ShutdownStatus;
    }
    else
    {
        /* ... otherwise it's a real logoff. Send the shutdown flags in that case. */
        Notif = LN_LOGOFF;
        Param = Flags;
    }

    // FIXME: At the moment, always send the notifications... In real world some checks are done.
    // if (hwndSAS && ( (Flags & EWX_SHUTDOWN) || RtlEqualLuid(CallerLuid, &SystemLuid)) )
    if (hwndSAS)
    {
        TRACE("\tSending %s message to Winlogon\n", Notif == LN_LOGOFF ? "LN_LOGOFF" : "LN_LOGOFF_CANCELED");
        UserPostMessage(hwndSAS, WM_LOGONNOTIFY, Notif, (LPARAM)Param);
        return TRUE;
    }
    else
    {
        ERR("hwndSAS == NULL\n");
    }

    return FALSE;
}

NTSTATUS
UserInitiateShutdown(IN PETHREAD Thread,
                     IN OUT PULONG pFlags)
{
    NTSTATUS Status;
    ULONG Flags = *pFlags;
    LUID CallerLuid;
    LUID SystemLuid = SYSTEM_LUID;
    static PRIVILEGE_SET ShutdownPrivilege =
    {
        1, PRIVILEGE_SET_ALL_NECESSARY,
        { {{SE_SHUTDOWN_PRIVILEGE, 0}, 0} }
    };

    PPROCESSINFO ppi;

    TRACE("UserInitiateShutdown\n");

    /* Get the caller's LUID */
    Status = GetProcessLuid(Thread, NULL, &CallerLuid);
    if (!NT_SUCCESS(Status))
    {
        ERR("UserInitiateShutdown: GetProcessLuid failed\n");
        return Status;
    }

    /*
     * Check if this is the System LUID, and adjust flags if needed.
     * In particular, be sure there is no EWX_CALLER_SYSTEM flag
     * spuriously set (could be the sign of malicous app!).
     */
    if (RtlEqualLuid(&CallerLuid, &SystemLuid))
        Flags |= EWX_CALLER_SYSTEM;
    else
        Flags &= ~EWX_CALLER_SYSTEM;

    *pFlags = Flags;

    /* Retrieve the Win32 process info */
    ppi = PsGetProcessWin32Process(PsGetThreadProcess(Thread));
    if (ppi == NULL)
    {
        ERR("UserInitiateShutdown: Failed to get win32 thread!\n");
        return STATUS_INVALID_HANDLE;
    }

    /* If the caller is not Winlogon, do some security checks */
    if (PsGetThreadProcessId(Thread) != gpidLogon)
    {
        /*
         * Here also, be sure there is no EWX_CALLER_WINLOGON flag
         * spuriously set (could be the sign of malicous app!).
         */
        Flags &= ~EWX_CALLER_WINLOGON;

        *pFlags = Flags;

        /* Check whether the current process is attached to a window station */
        if (ppi->prpwinsta == NULL)
        {
            ERR("UserInitiateShutdown: Process is not attached to a desktop\n");
            return STATUS_INVALID_HANDLE;
        }

        /* Check whether the window station of the current process can send exit requests */
        if (!RtlAreAllAccessesGranted(ppi->amwinsta, WINSTA_EXITWINDOWS))
        {
            ERR("UserInitiateShutdown: Caller doesn't have the rights to shutdown\n");
            return STATUS_ACCESS_DENIED;
        }

        /*
         * NOTE: USERSRV automatically adds the shutdown flag when we poweroff or reboot.
         *
         * If the caller wants to shutdown / reboot / power-off...
         */
        if (Flags & EWX_SHUTDOWN)
        {
            /* ... check whether it has shutdown privilege */
            if (!HasPrivilege(&ShutdownPrivilege))
            {
                ERR("UserInitiateShutdown: Caller doesn't have the rights to shutdown\n");
                return STATUS_PRIVILEGE_NOT_HELD;
            }
        }
        else
        {
            /*
             * ... but if it just wants to log-off, in case its
             * window station is a non-IO one, fail the call.
             */
            if (ppi->prpwinsta->Flags & WSS_NOIO)
            {
                ERR("UserInitiateShutdown: Caller doesn't have the rights to logoff\n");
                return STATUS_INVALID_DEVICE_REQUEST;
            }
        }
    }

    /* If the caller is not Winlogon, possibly notify it to perform the real shutdown */
    if (PsGetThreadProcessId(Thread) != gpidLogon)
    {
        // FIXME: HACK!! Do more checks!!
        TRACE("UserInitiateShutdown: Notify Winlogon for shutdown\n");
        NotifyLogon(hwndSAS, &CallerLuid, Flags, STATUS_SUCCESS);
        return STATUS_PENDING;
    }

    // If we reach this point, that means it's Winlogon that triggered the shutdown.
    TRACE("UserInitiateShutdown: Winlogon is doing a shutdown\n");

    /*
     * Update and save the shutdown flags globally for renotifying
     * Winlogon if needed, when calling EndShutdown.
     */
    Flags |= EWX_CALLER_WINLOGON; // Winlogon is doing a shutdown, be sure the internal flag is set.
    *pFlags = Flags;

    /* Save the shutdown flags now */
    gdwShutdownFlags = Flags;

    return STATUS_SUCCESS;
}

NTSTATUS
UserEndShutdown(IN PETHREAD Thread,
                IN NTSTATUS ShutdownStatus)
{
    NTSTATUS Status;
    ULONG Flags;
    LUID CallerLuid;

    TRACE("UserEndShutdown called\n");

    /*
     * FIXME: Some cleanup should be done when shutdown succeeds,
     * and some reset should be done when shutdown is cancelled.
     */
    //STUB;

    Status = GetProcessLuid(Thread, NULL, &CallerLuid);
    if (!NT_SUCCESS(Status))
    {
        ERR("UserEndShutdown: GetProcessLuid failed\n");
        return Status;
    }

    /* Copy the global flags because we're going to modify them for our purposes */
    Flags = gdwShutdownFlags;

    if (NT_SUCCESS(ShutdownStatus))
    {
        /* Just report success, and keep the shutdown flags as they are */
        ShutdownStatus = STATUS_SUCCESS;
    }
    else
    {
        /* Report the status to Winlogon and say that we cancel the shutdown */
        Flags |= EWX_SHUTDOWN_CANCELED;
        // FIXME: Should we reset gdwShutdownFlags to 0 ??
    }

    TRACE("UserEndShutdown: Notify Winlogon for end of shutdown\n");
    NotifyLogon(hwndSAS, &CallerLuid, Flags, ShutdownStatus);

    /* Always return success */
    return STATUS_SUCCESS;
}

/* EOF */