thread.c

这是一个开放源代码的与WINNT/WIN2K/WIN2003兼容的操作系统

 * @name CsrCreateThread
 * @implemented NT4
 *
 * The CsrCreateThread routine creates a CSR Thread object for an NT Thread.
 *
 * @param CsrProcess
 *        Pointer to the CSR Process which will contain the CSR Thread.
 *
 * @param hThread
 *        Handle to an existing NT Thread to which to associate this
 *        CSR Thread.
 *
 * @param ClientId
 *        Pointer to the Client ID structure of the NT Thread to associate
 *        with this CSR Thread.   
 *
 * @return STATUS_SUCCESS in case of success, STATUS_UNSUCCESSFUL
 *         othwerwise.
 *
 * @remarks None.
 *
 *--*/
NTSTATUS
NTAPI
CsrCreateThread(IN PCSR_PROCESS CsrProcess,
                IN HANDLE hThread,
                IN PCLIENT_ID ClientId)
{
    NTSTATUS Status;
    PCSR_THREAD CsrThread;
    PCSR_PROCESS CurrentProcess;
    PCSR_THREAD CurrentThread = NtCurrentTeb()->CsrClientThread;
    CLIENT_ID CurrentCid;
    KERNEL_USER_TIMES KernelTimes;

    DPRINT("CSRSRV: %s called\n", __FUNCTION__);

    /* Get the current thread and CID */
    CurrentCid = CurrentThread->ClientId;

    /* Acquire the Process Lock */
    CsrAcquireProcessLock();

    /* Get the current Process and make sure the Thread is valid with this CID */
    CurrentThread = CsrLocateThreadByClientId(&CurrentProcess,
                                              &CurrentCid);

    /* Something is wrong if we get an empty thread back */
    if (!CurrentThread)
    {
        DPRINT1("CSRSRV:%s: invalid thread!\n", __FUNCTION__);
        CsrReleaseProcessLock();
        return STATUS_THREAD_IS_TERMINATING;
    }

    /* Get the Thread Create Time */
    Status = NtQueryInformationThread(hThread,
                                      ThreadTimes,
                                      (PVOID)&KernelTimes,
                                      sizeof(KernelTimes),
                                      NULL);

    /* Allocate a CSR Thread Structure */
    if (!(CsrThread = CsrAllocateThread(CsrProcess)))
    {
        DPRINT1("CSRSRV:%s: out of memory!\n", __FUNCTION__);
        CsrReleaseProcessLock();
        return STATUS_NO_MEMORY;
    }

    /* Save the data we have */
    CsrThread->CreateTime = KernelTimes.CreateTime;
    CsrThread->ClientId = *ClientId;
    CsrThread->ThreadHandle = hThread;
    CsrThread->Flags = 0;

    /* Insert the Thread into the Process */
    CsrInsertThread(CsrProcess, CsrThread);

    /* Release the lock and return */
    CsrReleaseProcessLock();
    return STATUS_SUCCESS;
}

/*++
 * @name CsrDereferenceThread
 * @implemented NT4
 *
 * The CsrDereferenceThread routine removes a reference from a CSR Thread.
 *
 * @param CsrThread
 *        Pointer to the CSR Thread to dereference.
 *
 * @return None.
 *
 * @remarks If the reference count has reached zero (ie: the CSR Thread has
 *          no more active references), it will be deleted.
 *
 *--*/
VOID
NTAPI
CsrDereferenceThread(PCSR_THREAD CsrThread)
{
    /* Acquire process lock */
    CsrAcquireProcessLock();

    /* Decrease reference count */
    if (!(--CsrThread->ReferenceCount))
    {
        /* Call the generic cleanup code */
        CsrThreadRefcountZero(CsrThread);
    }
    else
    {
        /* Just release the lock */
        CsrReleaseProcessLock();
    }
}

/*++
 * @name CsrExecServerThread
 * @implemented NT4
 *
 * The CsrExecServerThread routine creates an NT Thread and then
 * initializes a CSR Thread for it.
 *
 * @param ThreadHandler
 *        Pointer to the thread's startup routine.
 *
 * @param Flags
 *        Initial CSR Thread Flags to set to the CSR Thread.    
 *
 * @return STATUS_SUCCESS in case of success, STATUS_UNSUCCESSFUL
 *         othwerwise.
 *
 * @remarks This routine is similar to CsrAddStaticServerThread, but it
 *          also creates an NT Thread instead of expecting one to already
 *          exist.
 *
 *--*/
NTSTATUS
NTAPI
CsrExecServerThread(IN PVOID ThreadHandler,
                    IN ULONG Flags)
{
    PCSR_THREAD CsrThread;
    HANDLE hThread;
    CLIENT_ID ClientId;
    NTSTATUS Status;

    /* Acquire process lock */
    CsrAcquireProcessLock();

    /* Allocate a CSR Thread in the Root Process */
    if (!(CsrThread = CsrAllocateThread(CsrRootProcess)))
    {
        /* Fail */
        CsrReleaseProcessLock();
        return STATUS_NO_MEMORY;
    }

    /* Create the Thread */
    Status = RtlCreateUserThread(NtCurrentProcess(),
                                 NULL,
                                 FALSE,
                                 0,
                                 0,
                                 0,
                                 ThreadHandler,
                                 NULL,
                                 &hThread,
                                 &ClientId);
    if (!NT_SUCCESS(Status))
    {
        /* Fail */
        CsrDeallocateThread(CsrThread);
        CsrReleaseProcessLock();
        return Status;
    }

    /* Setup the Thread Object */
    CsrThread->ThreadHandle = hThread;
    CsrThread->ClientId = ClientId;
    CsrThread->Flags = Flags;

    /* Insert it into the Thread List */
    InsertHeadList(&CsrRootProcess->ThreadList, &CsrThread->Link);

    /* Increase the thread count */
    CsrRootProcess->ThreadCount++;

    /* Return */
    CsrReleaseProcessLock();
    return Status;
}

/*++
 * @name CsrDestroyThread
 * @implemented NT4
 *
 * The CsrDestroyThread routine destroys the CSR Thread corresponding to 
 * a given Thread ID.
 *
 * @param Cid
 *        Pointer to the Client ID Structure corresponding to the CSR
 *        Thread which is about to be destroyed. 
 *
 * @return STATUS_SUCCESS in case of success, STATUS_THREAD_IS_TERMINATING
 *         if the CSR Thread is already terminating.
 *
 * @remarks None.
 *
 *--*/
NTSTATUS
NTAPI
CsrDestroyThread(IN PCLIENT_ID Cid)
{
    CLIENT_ID ClientId = *Cid;
    PCSR_THREAD CsrThread;
    PCSR_PROCESS CsrProcess;

    /* Acquire lock */
    CsrAcquireProcessLock();

    /* Find the thread */
    CsrThread = CsrLocateThreadByClientId(&CsrProcess,
                                          &ClientId);

    /* Make sure we got one back, and that it's not already gone */
    if (!CsrThread || CsrThread->Flags & CsrThreadTerminated)
    {
        /* Release the lock and return failure */
        CsrReleaseProcessLock();
        return STATUS_THREAD_IS_TERMINATING;
    }

    /* Set the terminated flag */
    CsrThread->Flags |= CsrThreadTerminated;

    /* Acquire the Wait Lock */
    CsrAcquireWaitLock();

    /* Do we have an active wait block? */
    if (CsrThread->WaitBlock)
    {
        /* Notify waiters of termination */
        CsrNotifyWaitBlock(CsrThread->WaitBlock,
                           NULL,
                           NULL,
                           NULL,
                           CsrProcessTerminating,
                           TRUE);
    }

    /* Release the Wait Lock */
    CsrReleaseWaitLock();

    /* Dereference the thread */
    CsrLockedDereferenceThread(CsrThread);

    /* Release the Process Lock and return success */
    CsrReleaseProcessLock();
    return STATUS_SUCCESS;
}

/*++
 * @name CsrImpersonateClient
 * @implemented NT4
 *
 * The CsrImpersonateClient will impersonate the given CSR Thread.
 *
 * @param CsrThread
 *        Pointer to the CSR Thread to impersonate.    
 *
 * @return TRUE if impersionation suceeded, false otherwise.
 *
 * @remarks Impersonation can be recursive.
 *
 *--*/
BOOLEAN
NTAPI
CsrImpersonateClient(IN PCSR_THREAD CsrThread)
{
    NTSTATUS Status;
    PCSR_THREAD CurrentThread = NtCurrentTeb()->CsrClientThread;

    /* Use the current thread if none given */
    if (!CsrThread) CsrThread = CurrentThread;

    /* Still no thread, something is wrong */
    if (!CsrThread)
    {
        /* Failure */
        return FALSE;
    }

    /* Make the call */
    Status = NtImpersonateThread(NtCurrentThread(),
                                 CsrThread->ThreadHandle,
                                 &CsrSecurityQos);

    if (!NT_SUCCESS(Status))
    {
        /* Failure */
        return FALSE;
    }

    /* Increase the impersonation count for the current thread */
    if (CurrentThread) ++CurrentThread->ImpersonationCount;

    /* Return Success */
    return TRUE;
}

/*++
 * @name CsrRevertToSelf
 * @implemented NT4
 *
 * The CsrRevertToSelf routine will attempt to remove an active impersonation.
 *
 * @param None.  
 *
 * @return TRUE if the reversion was succesful, false otherwise.
 *
 * @remarks Impersonation can be recursive; as such, the impersonation token
 *          will only be deleted once the CSR Thread's impersonaton count
 *          has reached zero.
 *
 *--*/
BOOLEAN
NTAPI
CsrRevertToSelf(VOID)
{
    NTSTATUS Status;
    PCSR_THREAD CurrentThread = NtCurrentTeb()->CsrClientThread;
    HANDLE ImpersonationToken = NULL;

    /* Check if we have a Current Thread */
    if (CurrentThread)
    {
        /* Make sure impersonation is on */
        if (!CurrentThread->ImpersonationCount)
        {
            return FALSE;
        }
        else if (--CurrentThread->ImpersonationCount > 0)
        {
            /* Success; impersonation count decreased but still not zero */
            return TRUE;
        }
    }

    /* Impersonation has been totally removed, revert to ourselves */
    Status = NtSetInformationThread(NtCurrentThread(),
                                    ThreadImpersonationToken,
                                    &ImpersonationToken,
                                    sizeof(HANDLE));

    /* Return TRUE or FALSE */
    return NT_SUCCESS(Status);
}

/*++
 * @name CsrLockThreadByClientId
 * @implemented NT4
 *
 * The CsrLockThreadByClientId routine locks the CSR Thread corresponding
 * to the given Thread ID and optionally returns it.
 *
 * @param Tid
 *        Thread ID corresponding to the CSR Thread which will be locked.
 *
 * @param CsrThread
 *        Optional pointer to a CSR Thread pointer which will hold the
 *        CSR Thread corresponding to the given Thread ID.
 *
 * @return STATUS_SUCCESS in case of success, STATUS_UNSUCCESSFUL
 *         othwerwise.
 *
 * @remarks Locking a CSR Thread is defined as acquiring an extra
 *          reference to it and returning with the Process Lock held.
 *
 *--*/
NTSTATUS
NTAPI
CsrLockThreadByClientId(IN HANDLE Tid,
                        OUT PCSR_THREAD *CsrThread OPTIONAL)
{
    PLIST_ENTRY ListHead, NextEntry;
    PCSR_THREAD CurrentThread = NULL;
    NTSTATUS Status = STATUS_UNSUCCESSFUL;
    ULONG i;

    /* Acquire the lock */
    CsrAcquireProcessLock();

    /* Convert to Hash */
    i = CsrHashThread(Tid);

    /* Setup the List Pointers */
    ListHead = &CsrThreadHashTable[i];
    NextEntry = ListHead;

    /* Start Loop */
    while (NextEntry != ListHead)
    {
        /* Get the Process */
        CurrentThread = CONTAINING_RECORD(NextEntry, CSR_THREAD, HashLinks);

        /* Check for PID Match */
        if ((CurrentThread->ClientId.UniqueThread == Tid) &&
            !(CurrentThread->Flags & CsrThreadTerminated))
        {
            /* Get out of here with success */
            Status = STATUS_SUCCESS;
            break;
        }

        /* Next entry */
        NextEntry = NextEntry->Flink;
    }

    /* Did the loop find something? */
    if (NT_SUCCESS(Status))
    {
        /* Reference the found thread */
        CurrentThread->ReferenceCount++;
    }
    else
    {
        /* Nothing found, release the lock */
        CsrReleaseProcessLock();
    }

    /* Return the status and thread */
    if (CsrThread) *CsrThread = CurrentThread;
    return Status;
}

/*++
 * @name CsrReferenceThread
 * @implemented NT4
 *
 * The CsrReferenceThread routine increases the active reference count of 
 * a CSR Thread.
 *
 * @param CsrThread
 *        Pointer to the CSR Thread whose reference count will be increased. 
 *
 * @return None.
 *
 * @remarks Do not use this routine if the Process Lock is already held.
 *
 *--*/
VOID
NTAPI
CsrReferenceThread(PCSR_THREAD CsrThread)
{
    /* Acquire process lock */
    CsrAcquireProcessLock();

    /* Increment reference count */
    CsrThread->ReferenceCount++;

    /* Release the lock */
    CsrReleaseProcessLock();
}

/*++
 * @name CsrUnlockThread
 * @implemented NT4
 *
 * The CsrUnlockThread undoes a previous CsrLockThreadByClientId operation.
 *
 * @param CsrThread
 *        Pointer to a previously locked CSR Thread. 
 *
 * @return STATUS_SUCCESS.
 *
 * @remarks This routine must be called with the Process Lock held.
 *
 *--*/
NTSTATUS
NTAPI
CsrUnlockThread(PCSR_THREAD CsrThread)
{
    /* Dereference the Thread */
    CsrLockedDereferenceThread(CsrThread);

    /* Release the lock and return */
    CsrReleaseProcessLock();
    return STATUS_SUCCESS;
}

/* EOF */