windows-nt/Source/XPSP1/NT/shell/lib/generic/thread.cpp

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// --------------------------------------------------------------------------
// Module Name: Thread.cpp
//
// Copyright (c) 1999-2000, Microsoft Corporation
//
// Base class that implements thread functionality. Subclass this class and
// implement the virtual ThreadEntry function. When you instantiate this
// class a thread gets created which will call ThreadEntry and when that
// function exits will call ThreadExit. These objects should be created using
// operator new because the default implementation of ThreadExit does
// "delete this". You should override this function if you don't want this
// behavior. The threads are also created SUSPENDED. You make any changes
// that are required in the subclass' constructor. At the end of the
// constructor or from the caller of operator new a "->Resume()" can be
// invoked to start the thread.
//
// History: 1999-08-24 vtan created
// 2000-02-01 vtan moved from Neptune to Whistler
// --------------------------------------------------------------------------
#include "StandardHeader.h"
#include "Thread.h"
#include "Access.h"
#include "Impersonation.h"
#include "StatusCode.h"
#include "TokenInformation.h"
// --------------------------------------------------------------------------
// CThread::CThread
//
// Arguments: stackSpace = Size of stack to reserve for this
// thread. Default = system default.
// createFlags = Additional flags designating how
// the thread should be created.
// Default = none.
// hToken = User token to assign to the
// thread. Default = none.
// pSecurityDescriptor = SecurityDescriptor to assign to
// thread. Default = none.
//
// Returns: <none>
//
// Purpose: Initializes the CThread object. Creates the thread SUSPENDED
// with given security attributes and assigns the hToken to the
// thread. The token need not have SecurityImpersonation as a
// duplicate is made with this access mode.
//
// History: 1999-08-24 vtan created
// 2000-02-01 vtan moved from Neptune to Whistler
// --------------------------------------------------------------------------
CThread::CThread (DWORD stackSpace, DWORD createFlags, HANDLE hToken) :
CCountedObject(),
_hThread(NULL),
_fCompleted(false)
{
DWORD dwThreadID;
// It is important to create the thread suspended. This constructor could
// get pre-empted by the system and does. If pre-empted whilst executing
// the constructor, the derived class is NOT fully constructed and the
// virtual table isn't correctly initialized.
_hThread = CreateThread(NULL,
stackSpace,
ThreadEntryProc,
this,
createFlags | CREATE_SUSPENDED,
&dwThreadID);
if (_hThread != NULL)
{
// Make a call to CCountedObject::AddRef here. This reference belongs
// to the thread. It's necessary to do it now because the creator of
// this thread can release its reference before the thread even begins
// executing which would cause the object to be released!
// CThread::ThreadEntryProc will release this reference when the
// thread's execution is finished. The creator of this thread should
// release its reference when it's done with the thread which may be
// immediately in the case of an asynhronous operation in which the
// thread cleans itself up.
AddRef();
// Impersonate the user token if given. Also grant access to the thread
// object to the user. This will allow them to query thread information.
if (hToken != NULL)
{
TSTATUS(SetToken(hToken));
}
}
}
// --------------------------------------------------------------------------
// CThread::~CThread
//
// Arguments: <none>
//
// Returns: <none>
//
// Purpose: Releases resources used by the CThread object on thread
// termination.
//
// History: 1999-08-24 vtan created
// --------------------------------------------------------------------------
CThread::~CThread (void)
{
ASSERTMSG(_fCompleted, "CThread::~CThread called before ThreadEntry() completed");
ReleaseHandle(_hThread);
}
// --------------------------------------------------------------------------
// CThread::operator HANDLE
//
// Arguments: <none>
//
// Returns: <none>
//
// Purpose: Magically converts a CThread to a HANDLE
//
// History: 1999-09-21 vtan created
// --------------------------------------------------------------------------
CThread::operator HANDLE (void) const
{
return(_hThread);
}
// --------------------------------------------------------------------------
// CThread::IsCreated
//
// Arguments: <none>
//
// Returns: bool
//
// Purpose: Returns whether a thread was created or not.
//
// History: 2000-09-08 vtan created
// --------------------------------------------------------------------------
bool CThread::IsCreated (void) const
{
return(_hThread != NULL);
}
// --------------------------------------------------------------------------
// CThread::Suspend
//
// Arguments: <none>
//
// Returns: <none>
//
// Purpose: Suspends thread execution.
//
// History: 1999-08-24 vtan created
// --------------------------------------------------------------------------
void CThread::Suspend (void) const
{
if (SuspendThread(_hThread) == 0xFFFFFFFF)
{
DISPLAYMSG("SuspendThread failed for thread handle in CThread::Suspend");
}
}
// --------------------------------------------------------------------------
// CThread::Resume
//
// Arguments: <none>
//
// Returns: <none>
//
// Purpose: Resumes thread execution.
//
// History: 1999-08-24 vtan created
// --------------------------------------------------------------------------
void CThread::Resume (void) const
{
if ((_hThread == NULL) || (ResumeThread(_hThread) == 0xFFFFFFFF))
{
DISPLAYMSG("ResumeThread failed for thread handle in CThread::Resume");
}
}
// --------------------------------------------------------------------------
// CThread::Terminate
//
// Arguments: <none>
//
// Returns: NTSTATUS
//
// Purpose: Forcibly terminates the thread. Use this with care. It should
// only be used in case a sub-class constructor fails and the
// thread is suspended and hasn't even run yet.
//
// History: 2000-10-18 vtan created
// --------------------------------------------------------------------------
NTSTATUS CThread::Terminate (void)
{
NTSTATUS status;
if (TerminateThread(_hThread, 0) != FALSE)
{
_fCompleted = true;
Release();
ReleaseHandle(_hThread);
status = STATUS_SUCCESS;
}
else
{
status = CStatusCode::StatusCodeOfLastError();
}
return(status);
}
// --------------------------------------------------------------------------
// CThread::IsCompleted
//
// Arguments: <none>
//
// Returns: bool
//
// Purpose: Determines whether the thread has completed execution. This
// does not check the signaled state of the thread handle but
// rather checks member variables.
//
// History: 1999-08-24 vtan created
// --------------------------------------------------------------------------
bool CThread::IsCompleted (void) const
{
DWORD dwExitCode;
return((GetExitCodeThread(_hThread, &dwExitCode) != FALSE) && (dwExitCode != STILL_ACTIVE));
}
// --------------------------------------------------------------------------
// CThread::WaitForCompletion
//
// Arguments: dwMilliseconds = Number of milliseconds to wait for
// thread completion.
//
// Returns: DWORD
//
// Purpose: Waits for the thread handle to become signaled.
//
// History: 1999-08-24 vtan created
// --------------------------------------------------------------------------
DWORD CThread::WaitForCompletion (DWORD dwMilliseconds) const
{
DWORD dwWaitResult;
do
{
// When waiting for the object check to see that it's not signaled.
// If signaled then abandon the wait loop. Otherwise allow user32
// to continue processing messages for this thread.
dwWaitResult = WaitForSingleObject(_hThread, 0);
if (dwWaitResult != WAIT_OBJECT_0)
{
dwWaitResult = MsgWaitForMultipleObjects(1, &_hThread, FALSE, dwMilliseconds, QS_ALLINPUT);
if (dwWaitResult == WAIT_OBJECT_0 + 1)
{
MSG msg;
if (PeekMessage(&msg, NULL, 0, 0, PM_REMOVE) != FALSE)
{
(BOOL)TranslateMessage(&msg);
(LRESULT)DispatchMessage(&msg);
}
}
}
} while (dwWaitResult == WAIT_OBJECT_0 + 1);
return(dwWaitResult);
}
// --------------------------------------------------------------------------
// CThread::GetResult
//
// Arguments: <none>
//
// Returns: DWORD
//
// Purpose: Gets the thread's exit code. This assumes it has completed
// execution and returns STILL_ACTIVE if not completed.
//
// History: 1999-08-24 vtan created
// --------------------------------------------------------------------------
DWORD CThread::GetResult (void) const
{
DWORD dwResult;
if (GetExitCodeThread(_hThread, &dwResult) == FALSE)
{
dwResult = STILL_ACTIVE;
}
return(dwResult);
}
// --------------------------------------------------------------------------
// CThread::GetPriority
//
// Arguments: <none>
//
// Returns: int
//
// Purpose: Gets the thread's priority.
//
// History: 1999-08-24 vtan created
// --------------------------------------------------------------------------
int CThread::GetPriority (void) const
{
return(GetThreadPriority(_hThread));
}
// --------------------------------------------------------------------------
// CThread::SetPriority
//
// Arguments: newPriority = New priority for the thread.
//
// Returns: <none>
//
// Purpose: Sets the thread's priority.
//
// History: 1999-08-24 vtan created
// --------------------------------------------------------------------------
void CThread::SetPriority (int newPriority) const
{
if (SetThreadPriority(_hThread, newPriority) == 0)
{
DISPLAYMSG("SetThreadPriorty failed in CThread::SetPriority");
}
}
// --------------------------------------------------------------------------
// CThread::ThreadExit
//
// Arguments: <none>
//
// Returns: <none>
//
// Purpose: Default base class implementation of thread exit. For threads
// whose execution is self contained and termination is not an
// issue then this will clean up after the thread. This function
// should be overriden if this behavior is NOT desired.
//
// History: 1999-08-24 vtan created
// --------------------------------------------------------------------------
void CThread::Exit (void)
{
}
// --------------------------------------------------------------------------
// CThread::SetToken
//
// Arguments: hToken = HANDLE to the user token to assign to this thread.
//
// Returns: NTSTATUS
//
// Purpose: Sets the impersonation token associated with this thread so
// the thread will execute in the user's context from the start.
//
// History: 1999-09-23 vtan created
// --------------------------------------------------------------------------
NTSTATUS CThread::SetToken (HANDLE hToken)
{
PSID pLogonSID;
CTokenInformation tokenInformation(hToken);
pLogonSID = tokenInformation.GetLogonSID();
if (pLogonSID != NULL)
{
CSecuredObject threadSecurity(_hThread, SE_KERNEL_OBJECT);
TSTATUS(threadSecurity.Allow(pLogonSID,
THREAD_GET_CONTEXT | THREAD_QUERY_INFORMATION,
0));
TSTATUS(CImpersonation::ImpersonateUser(_hThread, hToken));
}
return(STATUS_SUCCESS);
}
// --------------------------------------------------------------------------
// CThread::ThreadEntryProc
//
// Arguments: pParameter = "this" object.
//
// Returns: DWORD
//
// Purpose: Entry procedure for the thread. This manages the type-casting
// and invokation of CThread::ThreadEntry and CThread::ThreadExit
// as well as the _fCompleted member variable.
//
// History: 1999-08-24 vtan created
// --------------------------------------------------------------------------
DWORD WINAPI CThread::ThreadEntryProc (void *parameter)
{
DWORD dwThreadResult;
CThread *pThread;
pThread = static_cast<CThread*>(parameter);
dwThreadResult = pThread->Entry();
pThread->_fCompleted = true;
pThread->Exit();
pThread->Release();
return(dwThreadResult);
}