Leaked source code of windows server 2003
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/*++
Copyright (c) 1995 Microsoft Corporation
Module Name:
common\trace\worker.c
Abstract:
Worker threads for the router process
Revision History:
Gurdeep Singh Pall 7/28/95 Created
12-10-97: lokeshs: removed blocking of InitializeWorkerThread()
on initialization of the first AlertableThread() created
--*/
#include <nt.h>
#include <ntrtl.h>
#include <nturtl.h>
#include <windows.h>
#include <stdio.h>
#include <string.h>
#include <malloc.h>
#include <rtutils.h>
//#define STRSAFE_LIB
#include <strsafe.h>
#include "trace.h"
#include "workerinc.h"
// Time that thread has to be idle before exiting
LARGE_INTEGER ThreadIdleTO = {
(ULONG)(THREAD_IDLE_TIMEOUT*(-10000000)),
0xFFFFFFFF};
// Time that the worker queue is not served before starting new thread
CONST LARGE_INTEGER WorkQueueTO = {
(ULONG)(WORK_QUEUE_TIMEOUT*(-10000000)),
0xFFFFFFFF};
// Total number of threads
LONG ThreadCount;
// Number of threads waiting on the completion port
LONG ThreadsWaiting;
// Min allowed number of threads
LONG MinThreads;
// Completion port for threads to wait on
HANDLE WorkQueuePort;
// Timer to intiate creation of new thread if worker queue is not
// server within a timeout
HANDLE WorkQueueTimer;
// Queue for alertable work items
LIST_ENTRY AlertableWorkQueue ;
// Lock for the alertable work item queue
CRITICAL_SECTION AlertableWorkQueueLock ;
// Heap for alertable work items
HANDLE AlertableWorkerHeap ;
// Worker Semaphore used for releasing alertable worker threads
HANDLE AlertableThreadSemaphore;
// Number of alertable threads
LONG AlertableThreadCount;
volatile LONG WorkersInitialized=WORKERS_NOT_INITIALIZED;
//* WorkerThread()
//
// Function: Thread to execute work items in.
//
// Returns: Nothing
//
//*
DWORD APIENTRY
WorkerThread (
LPVOID param
) {
// It'll be waiting
InterlockedIncrement (&ThreadsWaiting);
do {
LPOVERLAPPED_COMPLETION_ROUTINE completionRoutine;
NTSTATUS status;
PVOID context;
IO_STATUS_BLOCK ioStatus;
status = NtRemoveIoCompletion (
WorkQueuePort,
(PVOID *)&completionRoutine,
&context,
&ioStatus,
&ThreadIdleTO);
if (NT_SUCCESS (status)) {
switch (status) {
// We did dequeue a work item
case STATUS_SUCCESS:
if (InterlockedExchangeAdd (&ThreadsWaiting, -1)==1) {
// Last thread to wait, start the timer
// to create a new thread
SetWaitableTimer (WorkQueueTimer,
&WorkQueueTO,
0,
NULL, NULL,
FALSE);
}
// Execute work item/completion routine
completionRoutine (
// Quick check for success that all work items
// and most of IRP complete with
(ioStatus.Status==STATUS_SUCCESS)
? NO_ERROR
: RtlNtStatusToDosError (ioStatus.Status),
(DWORD)ioStatus.Information,
(LPOVERLAPPED)context);
if (InterlockedExchangeAdd (&ThreadsWaiting, 1)==0) {
// Cancel time if this is the first thread
// to return
CancelWaitableTimer (WorkQueueTimer);
}
break;
// Thread was not used for ThreadIdle timeout, see
// if we need to quit
case STATUS_TIMEOUT:
while (1) {
// Make a local copy of the count and
// attempt to atomically check and update
// it if necessary
LONG count = ThreadCount;
// Quick check for min thread condition
if (count<=MinThreads)
break;
else {
// Attempt to decrease the count
// use another local variable
// because of MIPS optimizer bug
LONG newCount = count-1;
if (InterlockedCompareExchange (&ThreadCount,
newCount, count)==count) {
// Succeded, exit the thread
goto ExitThread;
}
// else try again
}
}
break;
default:
ASSERTMSG ("Unexpected status code returned ", FALSE);
break;
}
}
// Execute while we are initialized
}
while (WorkersInitialized==WORKERS_INITIALIZED);
ExitThread:
InterlockedDecrement (&ThreadsWaiting);
return 0;
}
//* AlertableWorkerThread()
//
// Function: Alertable work item thread
//
// Returns: Nothing
//
//*
DWORD APIENTRY
AlertableWorkerThread (
LPVOID param
) {
HANDLE WaitArray [] = {
#define ALERTABLE_THREAD_SEMAPHORE WAIT_OBJECT_0
AlertableThreadSemaphore,
#define WORK_QUEUE_TIMER (WAIT_OBJECT_0+1)
WorkQueueTimer
};
do {
WorkItem *workitem;
DWORD rc;
// Wait for signal to run
//
rc = WaitForMultipleObjectsEx (
sizeof (WaitArray)/sizeof (WaitArray[0]),
WaitArray,
FALSE,
INFINITE,
TRUE);
switch (rc) {
case ALERTABLE_THREAD_SEMAPHORE:
// Pick up and execute the worker
EnterCriticalSection (&AlertableWorkQueueLock);
ASSERT (!IsListEmpty (&AlertableWorkQueue));
workitem = (WorkItem *) RemoveHeadList (&AlertableWorkQueue) ;
LeaveCriticalSection (&AlertableWorkQueueLock);
(workitem->WI_Function) (workitem->WI_Context);
HeapFree (AlertableWorkerHeap, 0, workitem);
break;
case WORK_QUEUE_TIMER:
// Work queue has not been served wothin specified
// timeout
while (1) {
// Make a local copy of the count
LONG count = ThreadCount;
// Make sure we havn't exceded the limit
if (count>=MAX_WORKER_THREADS)
break;
else {
// Try to increment the value
// use another local variable
// because of MIPS optimizer bug
LONG newCount = count+1;
if (InterlockedCompareExchange (&ThreadCount,
newCount, count)==count) {
HANDLE hThread;
DWORD tid;
// Create new thread if increment succeded
hThread = CreateThread (NULL, 0, WorkerThread, NULL, 0, &tid);
if (hThread!=NULL) {
CloseHandle (hThread);
}
else // Restore the value if thread creation
// failed
InterlockedDecrement (&ThreadCount);
break;
}
// else repeat the loop if ThreadCount was modified
// while we were checking
}
}
break;
case WAIT_IO_COMPLETION:
// Handle IO completion
break;
case 0xFFFFFFFF:
// Error, we must have closed the semaphore handle
break;
default:
ASSERTMSG ("Unexpected rc from WaitForObject ", FALSE);
}
}
while (WorkersInitialized==WORKERS_INITIALIZED);
return 0 ;
}
//* WorkerCompletionRoutine
//
// Function: Worker function wrapper for non-io work items
//
VOID WINAPI
WorkerCompletionRoutine (
DWORD dwErrorCode,
PVOID ActualContext,
LPOVERLAPPED ActualCompletionRoutine
) {
UNREFERENCED_PARAMETER (dwErrorCode);
((WORKERFUNCTION)ActualCompletionRoutine)(ActualContext);
}
//* InitializeWorkerThread()
//
// Function: Called by the first work item
//
// Returns: WORKERS_INITIALIZED if successful.
// WORKERS_NOT_INITIALIZED not.
//*
LONG
InitializeWorkerThread (
LONG initFlag
) {
DWORD dwErr;
#if 0
if (initFlag==WORKERS_INITIALIZING) {
#if DBG
DbgPrint ("RTUTILS: %lx - waiting for worker initialization.\n", GetCurrentThreadId ());
#endif
while (WorkersInitialized==WORKERS_INITIALIZING)
Sleep (100);
#if DBG
DbgPrint ("RTUTILS: %lx - wait for worker initialization done.\n", GetCurrentThreadId ());
#endif
}
if (WorkersInitialized==WORKERS_INITIALIZED) {
return WORKERS_INITIALIZED;
}
else {
INT i;
DWORD tid;
HANDLE threadhandle;
SYSTEM_INFO systeminfo;
// Get number of processors
//
GetSystemInfo (&systeminfo) ;
MinThreads = systeminfo.dwNumberOfProcessors;
ThreadsWaiting = 0;
// Init critical section
//
InitializeCriticalSection (&AlertableWorkQueueLock);
// Initialize work queue
//
InitializeListHead (&AlertableWorkQueue) ;
// Allocate private heap
//
AlertableWorkerHeap = HeapCreate (0, // no flags
systeminfo.dwPageSize,// initial heap size
0); // no maximum size
if (AlertableWorkerHeap != NULL) {
// Create counting semaphore for releasing alertable threads
AlertableThreadSemaphore = CreateSemaphore(NULL, // No security
0, // Initial value
MAXLONG, // Max items to queue
NULL); // No name
if (AlertableThreadSemaphore!=NULL) {
// Create completion port for work items
WorkQueuePort = CreateIoCompletionPort (
INVALID_HANDLE_VALUE, // Just create a port, no file yet
NULL, // New port
0, // Key is ignored
MAX_WORKER_THREADS); // Number of active threads
if (WorkQueuePort!=NULL) {
// Create timer to trigger creation of
// new threads if work queue is not served
// for the specified timeout
WorkQueueTimer = CreateWaitableTimer (
NULL, // No security
FALSE, // auto-reset
NULL); // No name
if (WorkQueueTimer!=NULL) {
// Start Alertable threads
//
//
// initialize the global structure for wait threads
//
dwErr = InitializeWaitGlobal();
if (dwErr!=NO_ERROR) {
DeInitializeWaitGlobal();
goto ThreadCreationError;
}
/*WTG.g_InitializedEvent = CreateEvent(NULL, FALSE, FALSE, NULL);
if (WTG.g_InitializedEvent==NULL)
goto ThreadCreationError;
*/
//
// create one alertable thread and wait for it to get initialized
// This makes sure that at least one server thread is initialized
// before the others attemp to use it.
//
i =0;
threadhandle = CreateThread (
NULL, // No security
0, // Default stack
AlertableWaitWorkerThread,// Start routine
(PVOID)(LONG_PTR)i, // Thread param
0, // No flags
&tid);
if (threadhandle!=NULL)
CloseHandle (threadhandle);
else
goto ThreadCreationError;
/*
WaitForSingleObject(WTG.g_InitializedEvent, INFINITE);
CloseHandle(WTG.g_InitializedEvent);
*/
/*
//
// create the other alertable threads but dont wait on them to
// get initialization
//
for (i=1; i < NUM_ALERTABLE_THREADS; i++) {
threadhandle = CreateThread (
NULL, // No security
0, // Default stack
AlertableWaitWorkerThread,// Start routine
(PVOID)(LONG_PTR)i, // Thread id
0, // No flags
&tid);
if (threadhandle!=NULL)
CloseHandle (threadhandle);
else
goto ThreadCreationError;
}
*/
// Start the rest of worker threads
//
for (i=0; i < MinThreads; i++) {
threadhandle = CreateThread (
NULL, // No security
0, // Default stack
WorkerThread,// Start routine
NULL, // No parameter
0, // No flags
&tid) ;
if (threadhandle!=NULL)
CloseHandle (threadhandle);
else
goto ThreadCreationError;
}
ThreadCount = i;
WorkersInitialized = WORKERS_INITIALIZED;
return WORKERS_INITIALIZED;
ThreadCreationError:
// Cleanup in case of failure
// Threads will exit by themselves when objects are
// deleted
CloseHandle (WorkQueueTimer);
}
CloseHandle (WorkQueuePort);
}
CloseHandle (AlertableThreadSemaphore);
}
HeapDestroy (AlertableWorkerHeap);
}
DeleteCriticalSection (&AlertableWorkQueueLock);
#if DBG
DbgPrint ("RTUTILS: %lx - worker initialization failed (%ld).\n",
GetCurrentThreadId (), GetLastError ());
#endif
return WORKERS_NOT_INITIALIZED;
}
#endif
return WORKERS_NOT_INITIALIZED;
}
//* StopWorkers()
//
// Function: Cleanup worker thread when dll is unloaded
//
//*
VOID
StopWorkers (
VOID
) {
// Make sure we were initialized
if (WorkersInitialized==WORKERS_INITIALIZED) {
// All work items should have been completed
// already (no other components should be using
// our routines or we shouldn't have been unloaded)
// Set the flag telling all threads to quit
WorkersInitialized = WORKERS_NOT_INITIALIZED;
// Close all syncronization objects (this should
// terminate the wait)
if (WorkQueueTimer)
CloseHandle (WorkQueueTimer);
if (WorkQueuePort)
CloseHandle (WorkQueuePort);
if (AlertableThreadSemaphore)
CloseHandle (AlertableThreadSemaphore);
// Let threads complete
Sleep (1000);
// Destroy the rest
if (AlertableWorkerHeap)
HeapDestroy (AlertableWorkerHeap);
DeleteCriticalSection (&AlertableWorkQueueLock);
}
}
//* QueueWorkItem()
//
// Function: Queues the supplied work item in the work queue.
//
// Returns: 0 (success)
// Win32 error codes for cases like out of memory
//
//*
DWORD APIENTRY
QueueWorkItem (WORKERFUNCTION functionptr, PVOID context, BOOL serviceinalertablethread)
{
DWORD retcode ;
LONG initFlag;
if (functionptr == NULL)
return ERROR_INVALID_PARAMETER;
// if uninitialized, attempt to initialize worker threads
//
if (!ENTER_WORKER_API) {
retcode = GetLastError();
return (retcode == NO_ERROR ? ERROR_CAN_NOT_COMPLETE : retcode);
}
// based on this flag insert in either the alertablequeue or the workerqueue
//
if (!serviceinalertablethread) {
NTSTATUS status;
// Use completion port to execute the item
status = NtSetIoCompletion (
WorkQueuePort, // Port
(PVOID)WorkerCompletionRoutine, // Completion routine
functionptr, // Apc context
STATUS_SUCCESS, // Status
(ULONG_PTR)context); // Information ()
if (status==STATUS_SUCCESS)
retcode = NO_ERROR;
else
retcode = RtlNtStatusToDosError (status);
}
else {
// Create and queue work item
WorkItem *workitem ;
workitem = (WorkItem *) HeapAlloc (
AlertableWorkerHeap,
0, // No flags
sizeof (WorkItem));
if (workitem != NULL) {
workitem->WI_Function = functionptr ;
workitem->WI_Context = context ;
EnterCriticalSection (&AlertableWorkQueueLock) ;
InsertTailList (&AlertableWorkQueue, &workitem->WI_List) ;
LeaveCriticalSection (&AlertableWorkQueueLock) ;
// let a worker thread run if waiting
//
ReleaseSemaphore (AlertableThreadSemaphore, 1, NULL) ;
retcode = 0 ;
}
else
retcode = ERROR_NOT_ENOUGH_MEMORY ;
}
return retcode ;
}
// Function: Associates file handle with the completion port (all
// asynchronous io on this handle will be queued to the
// completion port)
//
// FileHandle: file handle to be associated with completion port
// CompletionProc: procedure to be called when io associated with
// the file handle completes. This function will be
// executed in the context of non-alertable worker thread
DWORD
APIENTRY
SetIoCompletionProc (
IN HANDLE FileHandle,
IN LPOVERLAPPED_COMPLETION_ROUTINE CompletionProc
) {
HANDLE hdl;
LONG initFlag;
DWORD retcode;
if (!CompletionProc)
return ERROR_INVALID_PARAMETER;
if (FileHandle==NULL || FileHandle==INVALID_HANDLE_VALUE)
return ERROR_INVALID_PARAMETER;
// if uninitialized, attempt to initialize worker threads
//
if (!ENTER_WORKER_API) {
retcode = GetLastError();
return (retcode == NO_ERROR ? ERROR_CAN_NOT_COMPLETE : retcode);
}
hdl = CreateIoCompletionPort (FileHandle,
WorkQueuePort,
(UINT_PTR)CompletionProc,
0);
if (hdl!=NULL)
return NO_ERROR;
else
return GetLastError ();
}