/**

 * WinPR: Windows Portable Runtime

 * Process Thread Functions

 *

 * Copyright 2012 Marc-Andre Moreau <marcandre.moreau@gmail.com>

 * Copyright 2015 Hewlett-Packard Development Company, L.P.

 * Copyright 2021 David Fort <contact@hardening-consulting.com>

 *

 *

 * Licensed under the Apache License, Version 2.0 (the "License");

 * you may not use this file except in compliance with the License.

 * You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

#include <winpr/config.h>

#include <winpr/assert.h>

#include <winpr/handle.h>

#include <winpr/thread.h>

/**

 * api-ms-win-core-processthreads-l1-1-1.dll

 *

 * CreateRemoteThread

 * CreateRemoteThreadEx

 * CreateThread

 * DeleteProcThreadAttributeList

 * ExitThread

 * FlushInstructionCache

 * FlushProcessWriteBuffers

 * GetCurrentThread

 * GetCurrentThreadId

 * GetCurrentThreadStackLimits

 * GetExitCodeThread

 * GetPriorityClass

 * GetStartupInfoW

 * GetThreadContext

 * GetThreadId

 * GetThreadIdealProcessorEx

 * GetThreadPriority

 * GetThreadPriorityBoost

 * GetThreadTimes

 * InitializeProcThreadAttributeList

 * OpenThread

 * OpenThreadToken

 * QueryProcessAffinityUpdateMode

 * QueueUserAPC

 * ResumeThread

 * SetPriorityClass

 * SetThreadContext

 * SetThreadPriority

 * SetThreadPriorityBoost

 * SetThreadStackGuarantee

 * SetThreadToken

 * SuspendThread

 * SwitchToThread

 * TerminateThread

 * UpdateProcThreadAttribute

 */

#ifndef _WIN32

#include <winpr/crt.h>

#include <winpr/platform.h>

#ifdef WINPR_HAVE_UNISTD_H

#include <unistd.h>

#endif

#ifdef WINPR_HAVE_SYS_EVENTFD_H

#include <sys/eventfd.h>

#endif

#include <winpr/debug.h>

#include <errno.h>

#include <fcntl.h>

#include <winpr/collections.h>

#include "thread.h"

#include "apc.h"

#include "../handle/handle.h"

#include "../log.h"

#define TAG WINPR_TAG("thread")

static WINPR_THREAD mainThread;

#if defined(WITH_THREAD_LIST)

static wListDictionary* thread_list = NULL;

#endif

static BOOL ThreadCloseHandle(HANDLE handle);

static void cleanup_handle(void* obj);

static BOOL ThreadIsHandled(HANDLE handle)

{

  return WINPR_HANDLE_IS_HANDLED(handle, HANDLE_TYPE_THREAD, FALSE);

}

static int ThreadGetFd(HANDLE handle)

{

  WINPR_THREAD* pThread = (WINPR_THREAD*)handle;

  if (!ThreadIsHandled(handle))

    return -1;

  return pThread->event.fds[0];

}

#define run_mutex_init(fkt, mux, arg) run_mutex_init_(fkt, #fkt, mux, arg)

static BOOL run_mutex_init_(int (*fkt)(pthread_mutex_t*, const pthread_mutexattr_t*),

                            const char* name, pthread_mutex_t* mutex,

                            const pthread_mutexattr_t* mutexattr)

{

  int rc;

  WINPR_ASSERT(fkt);

  WINPR_ASSERT(mutex);

  rc = fkt(mutex, mutexattr);

  if (rc != 0)

  {

    WLog_WARN(TAG, "[%s] failed with [%s]", name, strerror(rc));

  }

  return rc == 0;

}

#define run_mutex_fkt(fkt, mux) run_mutex_fkt_(fkt, #fkt, mux)

static BOOL run_mutex_fkt_(int (*fkt)(pthread_mutex_t* mux), const char* name,

                           pthread_mutex_t* mutex)

{

  int rc;

  WINPR_ASSERT(fkt);

  WINPR_ASSERT(mutex);

  rc = fkt(mutex);

  if (rc != 0)

  {

    WLog_WARN(TAG, "[%s] failed with [%s]", name, strerror(rc));

  }

  return rc == 0;

}

#define run_cond_init(fkt, cond, arg) run_cond_init_(fkt, #fkt, cond, arg)

static BOOL run_cond_init_(int (*fkt)(pthread_cond_t*, const pthread_condattr_t*), const char* name,

                           pthread_cond_t* condition, const pthread_condattr_t* conditionattr)

{

  int rc;

  WINPR_ASSERT(fkt);

  WINPR_ASSERT(condition);

  rc = fkt(condition, conditionattr);

  if (rc != 0)

  {

    WLog_WARN(TAG, "[%s] failed with [%s]", name, strerror(rc));

  }

  return rc == 0;

}

#define run_cond_fkt(fkt, cond) run_cond_fkt_(fkt, #fkt, cond)

static BOOL run_cond_fkt_(int (*fkt)(pthread_cond_t* mux), const char* name,

                          pthread_cond_t* condition)

{

  int rc;

  WINPR_ASSERT(fkt);

  WINPR_ASSERT(condition);

  rc = fkt(condition);

  if (rc != 0)

  {

    WLog_WARN(TAG, "[%s] failed with [%s]", name, strerror(rc));

  }

  return rc == 0;

}

static int pthread_mutex_checked_unlock(pthread_mutex_t* mutex)

{

  WINPR_ASSERT(mutex);

  WINPR_ASSERT(pthread_mutex_trylock(mutex) == EBUSY);

  return pthread_mutex_unlock(mutex);

}

static BOOL mux_condition_bundle_init(mux_condition_bundle* bundle)

{

  WINPR_ASSERT(bundle);

  bundle->val = FALSE;

  if (!run_mutex_init(pthread_mutex_init, &bundle->mux, NULL))

    return FALSE;

  if (!run_cond_init(pthread_cond_init, &bundle->cond, NULL))

    return FALSE;

  return TRUE;

}

static void mux_condition_bundle_uninit(mux_condition_bundle* bundle)

{

  mux_condition_bundle empty = { 0 };

  WINPR_ASSERT(bundle);

  run_cond_fkt(pthread_cond_destroy, &bundle->cond);

  run_mutex_fkt(pthread_mutex_destroy, &bundle->mux);

  *bundle = empty;

}

static BOOL mux_condition_bundle_signal(mux_condition_bundle* bundle)

{

  BOOL rc = TRUE;

  WINPR_ASSERT(bundle);

  if (!run_mutex_fkt(pthread_mutex_lock, &bundle->mux))

    return FALSE;

  bundle->val = TRUE;

  if (!run_cond_fkt(pthread_cond_signal, &bundle->cond))

    rc = FALSE;

  if (!run_mutex_fkt(pthread_mutex_checked_unlock, &bundle->mux))

    rc = FALSE;

  return rc;

}

static BOOL mux_condition_bundle_lock(mux_condition_bundle* bundle)

{

  WINPR_ASSERT(bundle);

  return run_mutex_fkt(pthread_mutex_lock, &bundle->mux);

}

static BOOL mux_condition_bundle_unlock(mux_condition_bundle* bundle)

{

  WINPR_ASSERT(bundle);

  return run_mutex_fkt(pthread_mutex_checked_unlock, &bundle->mux);

}

static BOOL mux_condition_bundle_wait(mux_condition_bundle* bundle, const char* name)

{

  BOOL rc = FALSE;

  WINPR_ASSERT(bundle);

  WINPR_ASSERT(name);

  WINPR_ASSERT(pthread_mutex_trylock(&bundle->mux) == EBUSY);

  while (!bundle->val)

  {

    int r = pthread_cond_wait(&bundle->cond, &bundle->mux);

    if (r != 0)

    {

      WLog_ERR(TAG, "failed to wait for %s [%s]", name, strerror(r));

      switch (r)

      {

        case ENOTRECOVERABLE:

        case EPERM:

        case ETIMEDOUT:

        case EINVAL:

          goto fail;

        default:

          break;

      }

    }

  }

  rc = bundle->val;

fail:

  return rc;

}

static BOOL signal_thread_ready(WINPR_THREAD* thread)

{

  WINPR_ASSERT(thread);

  return mux_condition_bundle_signal(&thread->isCreated);

}

static BOOL signal_thread_is_running(WINPR_THREAD* thread)

{

  WINPR_ASSERT(thread);

  return mux_condition_bundle_signal(&thread->isRunning);

}

static DWORD ThreadCleanupHandle(HANDLE handle)

{

  DWORD status = WAIT_FAILED;

  WINPR_THREAD* thread = (WINPR_THREAD*)handle;

  if (!ThreadIsHandled(handle))

    return WAIT_FAILED;

  if (!run_mutex_fkt(pthread_mutex_lock, &thread->mutex))

    return WAIT_FAILED;

  if (!thread->joined)

  {

    int rc = pthread_join(thread->thread, NULL);

    if (rc != 0)

    {

      WLog_ERR(TAG, "pthread_join failure: [%d] %s", rc, strerror(rc));

      goto fail;

    }

    else

      thread->joined = TRUE;

  }

  status = WAIT_OBJECT_0;

fail:

  if (!run_mutex_fkt(pthread_mutex_checked_unlock, &thread->mutex))

    return WAIT_FAILED;

  return status;

}

static HANDLE_OPS ops = { ThreadIsHandled,

                        ThreadCloseHandle,

                        ThreadGetFd,

                        ThreadCleanupHandle,

                        NULL,

                        NULL,

                        NULL,

                        NULL,

                        NULL,

                        NULL,

                        NULL,

                        NULL,

                        NULL,

                        NULL,

                        NULL,

                        NULL,

                        NULL,

                        NULL,

                        NULL,

                        NULL,

                        NULL };

static void dump_thread(WINPR_THREAD* thread)

{

#if defined(WITH_DEBUG_THREADS)

  void* stack = winpr_backtrace(20);

  char** msg;

  size_t used, i;

  WLog_DBG(TAG, "Called from:");

  msg = winpr_backtrace_symbols(stack, &used);

  for (i = 0; i < used; i++)

    WLog_DBG(TAG, "[%" PRIdz "]: %s", i, msg[i]);

  free(msg);

  winpr_backtrace_free(stack);

  WLog_DBG(TAG, "Thread handle created still not closed!");

  msg = winpr_backtrace_symbols(thread->create_stack, &used);

  for (i = 0; i < used; i++)

    WLog_DBG(TAG, "[%" PRIdz "]: %s", i, msg[i]);

  free(msg);

  if (thread->started)

  {

    WLog_DBG(TAG, "Thread still running!");

  }

  else if (!thread->exit_stack)

  {

    WLog_DBG(TAG, "Thread suspended.");

  }

  else

  {

    WLog_DBG(TAG, "Thread exited at:");

    msg = winpr_backtrace_symbols(thread->exit_stack, &used);

    for (i = 0; i < used; i++)

      WLog_DBG(TAG, "[%" PRIdz "]: %s", i, msg[i]);

    free(msg);

  }

#else

  WINPR_UNUSED(thread);

#endif

}

/**

 * TODO: implement thread suspend/resume using pthreads

 * http://stackoverflow.com/questions/3140867/suspend-pthreads-without-using-condition

 */

static BOOL set_event(WINPR_THREAD* thread)

{

  return winpr_event_set(&thread->event);

}

static BOOL reset_event(WINPR_THREAD* thread)

{

  return winpr_event_reset(&thread->event);

}

#if defined(WITH_THREAD_LIST)

static BOOL thread_compare(const void* a, const void* b)

{

  const pthread_t* p1 = a;

  const pthread_t* p2 = b;

  BOOL rc = pthread_equal(*p1, *p2);

  return rc;

}

#endif

static INIT_ONCE threads_InitOnce = INIT_ONCE_STATIC_INIT;

static pthread_t mainThreadId;

static DWORD currentThreadTlsIndex = TLS_OUT_OF_INDEXES;

static BOOL initializeThreads(PINIT_ONCE InitOnce, PVOID Parameter, PVOID* Context)

{

  if (!apc_init(&mainThread.apc))

  {

    WLog_ERR(TAG, "failed to initialize APC");

    goto out;

  }

  mainThread.common.Type = HANDLE_TYPE_THREAD;

  mainThreadId = pthread_self();

  currentThreadTlsIndex = TlsAlloc();

  if (currentThreadTlsIndex == TLS_OUT_OF_INDEXES)

  {

    WLog_ERR(TAG, "Major bug, unable to allocate a TLS value for currentThread");

  }

#if defined(WITH_THREAD_LIST)

  thread_list = ListDictionary_New(TRUE);

  if (!thread_list)

  {

    WLog_ERR(TAG, "Couldn't create global thread list");

    goto error_thread_list;

  }

  thread_list->objectKey.fnObjectEquals = thread_compare;

#endif

out:

  return TRUE;

}

static BOOL signal_and_wait_for_ready(WINPR_THREAD* thread)

{

  BOOL res = FALSE;

  WINPR_ASSERT(thread);

  if (!mux_condition_bundle_lock(&thread->isRunning))

    return FALSE;

  if (!signal_thread_ready(thread))

    goto fail;

  if (!mux_condition_bundle_wait(&thread->isRunning, "threadIsRunning"))

    goto fail;

#if defined(WITH_THREAD_LIST)

  if (!ListDictionary_Contains(thread_list, &thread->thread))

  {

    WLog_ERR(TAG, "Thread not in thread_list, startup failed!");

    goto fail;

  }

#endif

  res = TRUE;

fail:

  if (!mux_condition_bundle_unlock(&thread->isRunning))

    return FALSE;

  return res;

}

/* Thread launcher function responsible for registering

 * cleanup handlers and calling pthread_exit, if not done

 * in thread function. */

static void* thread_launcher(void* arg)

{

  DWORD rc = 0;

  WINPR_THREAD* thread = (WINPR_THREAD*)arg;

  LPTHREAD_START_ROUTINE fkt;

  if (!thread)

  {

    WLog_ERR(TAG, "Called with invalid argument %p", arg);

    goto exit;

  }

  if (!TlsSetValue(currentThreadTlsIndex, thread))

  {

    WLog_ERR(TAG, "thread %d, unable to set current thread value", pthread_self());

    goto exit;

  }

  if (!(fkt = thread->lpStartAddress))

  {

    WLog_ERR(TAG, "Thread function argument is %p", (void*)fkt);

    goto exit;

  }

  if (!signal_and_wait_for_ready(thread))

    goto exit;

  rc = fkt(thread->lpParameter);

exit:

  if (thread)

  {

    apc_cleanupThread(thread);

    if (!thread->exited)

      thread->dwExitCode = rc;

    set_event(thread);

    signal_thread_ready(thread);

    if (thread->detached || !thread->started)

      cleanup_handle(thread);

  }

  return NULL;

}

static BOOL winpr_StartThread(WINPR_THREAD* thread)

{

  BOOL rc = FALSE;

  BOOL locked = FALSE;

  pthread_attr_t attr = { 0 };

  if (!mux_condition_bundle_lock(&thread->isCreated))

    return FALSE;

  locked = TRUE;

  pthread_attr_init(&attr);

  pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE);

  if (thread->dwStackSize > 0)

    pthread_attr_setstacksize(&attr, (size_t)thread->dwStackSize);

  thread->started = TRUE;

  reset_event(thread);

#if defined(WITH_THREAD_LIST)

  if (!ListDictionary_Add(thread_list, &thread->thread, thread))

  {

    WLog_ERR(TAG, "failed to add the thread to the thread list");

    goto error;

  }

#endif

  if (pthread_create(&thread->thread, &attr, thread_launcher, thread))

    goto error;

  if (!mux_condition_bundle_wait(&thread->isCreated, "threadIsCreated"))

    goto error;

  locked = FALSE;

  if (!mux_condition_bundle_unlock(&thread->isCreated))

    goto error;

  if (!signal_thread_is_running(thread))

  {

    WLog_ERR(TAG, "failed to signal the thread was ready");

    goto error;

  }

  rc = TRUE;

error:

  if (locked)

  {

    if (!mux_condition_bundle_unlock(&thread->isCreated))

      rc = FALSE;

  }

  pthread_attr_destroy(&attr);

  if (rc)

    dump_thread(thread);

  return rc;

}

HANDLE CreateThread(LPSECURITY_ATTRIBUTES lpThreadAttributes, SIZE_T dwStackSize,

                    LPTHREAD_START_ROUTINE lpStartAddress, LPVOID lpParameter,

                    DWORD dwCreationFlags, LPDWORD lpThreadId)

{

  HANDLE handle;

  WINPR_THREAD* thread = (WINPR_THREAD*)calloc(1, sizeof(WINPR_THREAD));

  if (!thread)

    return NULL;

  thread->dwStackSize = dwStackSize;

  thread->lpParameter = lpParameter;

  thread->lpStartAddress = lpStartAddress;

  thread->lpThreadAttributes = lpThreadAttributes;

  thread->common.ops = &ops;

#if defined(WITH_DEBUG_THREADS)

  thread->create_stack = winpr_backtrace(20);

  dump_thread(thread);

#endif

  if (!winpr_event_init(&thread->event))

  {

    WLog_ERR(TAG, "failed to create event");

    goto fail;

  }

  if (!run_mutex_init(pthread_mutex_init, &thread->mutex, NULL))

  {

    WLog_ERR(TAG, "failed to initialize thread mutex");

    goto fail;

  }

  if (!apc_init(&thread->apc))

  {

    WLog_ERR(TAG, "failed to initialize APC");

    goto fail;

  }

  if (!mux_condition_bundle_init(&thread->isCreated))

    goto fail;

  if (!mux_condition_bundle_init(&thread->isRunning))

    goto fail;

  WINPR_HANDLE_SET_TYPE_AND_MODE(thread, HANDLE_TYPE_THREAD, WINPR_FD_READ);

  handle = (HANDLE)thread;

  InitOnceExecuteOnce(&threads_InitOnce, initializeThreads, NULL, NULL);

  if (!(dwCreationFlags & CREATE_SUSPENDED))

  {

    if (!winpr_StartThread(thread))

      goto fail;

  }

  else

  {

    if (!set_event(thread))

      goto fail;

  }

  return handle;

fail:

  cleanup_handle(thread);

  return NULL;

}

void cleanup_handle(void* obj)

{

  WINPR_THREAD* thread = (WINPR_THREAD*)obj;

  if (!thread)

    return;

  if (!apc_uninit(&thread->apc))

    WLog_ERR(TAG, "failed to destroy APC");

  mux_condition_bundle_uninit(&thread->isCreated);

  mux_condition_bundle_uninit(&thread->isRunning);

  run_mutex_fkt(pthread_mutex_destroy, &thread->mutex);

  winpr_event_uninit(&thread->event);

#if defined(WITH_THREAD_LIST)

  ListDictionary_Remove(thread_list, &thread->thread);

#endif

#if defined(WITH_DEBUG_THREADS)

  if (thread->create_stack)

    winpr_backtrace_free(thread->create_stack);

  if (thread->exit_stack)

    winpr_backtrace_free(thread->exit_stack);

#endif

  free(thread);

}

BOOL ThreadCloseHandle(HANDLE handle)

{

  WINPR_THREAD* thread = (WINPR_THREAD*)handle;

#if defined(WITH_THREAD_LIST)

  if (!thread_list)

  {

    WLog_ERR(TAG, "Thread list does not exist, check call!");

    dump_thread(thread);

  }

  else if (!ListDictionary_Contains(thread_list, &thread->thread))

  {

    WLog_ERR(TAG, "Thread list does not contain this thread! check call!");

    dump_thread(thread);

  }

  else

  {

    ListDictionary_Lock(thread_list);

#endif

    dump_thread(thread);

    if ((thread->started) && (WaitForSingleObject(thread, 0) != WAIT_OBJECT_0))

    {

      WLog_DBG(TAG, "Thread running, setting to detached state!");

      thread->detached = TRUE;

      pthread_detach(thread->thread);

    }

    else

    {

      cleanup_handle(thread);

    }

#if defined(WITH_THREAD_LIST)

    ListDictionary_Unlock(thread_list);

  }

#endif

  return TRUE;

}

HANDLE CreateRemoteThread(HANDLE hProcess, LPSECURITY_ATTRIBUTES lpThreadAttributes,

                          SIZE_T dwStackSize, LPTHREAD_START_ROUTINE lpStartAddress,

                          LPVOID lpParameter, DWORD dwCreationFlags, LPDWORD lpThreadId)

{

  WLog_ERR(TAG, "not implemented");

  SetLastError(ERROR_CALL_NOT_IMPLEMENTED);

  return NULL;

}

VOID ExitThread(DWORD dwExitCode)

{

#if defined(WITH_THREAD_LIST)

  DWORD rc;

  pthread_t tid = pthread_self();

  if (!thread_list)

  {

    WLog_ERR(TAG, "function called without existing thread list!");

#if defined(WITH_DEBUG_THREADS)

    DumpThreadHandles();

#endif

    pthread_exit(0);

  }

  else if (!ListDictionary_Contains(thread_list, &tid))

  {

    WLog_ERR(TAG, "function called, but no matching entry in thread list!");

#if defined(WITH_DEBUG_THREADS)

    DumpThreadHandles();

#endif

    pthread_exit(0);

  }

  else

  {

    WINPR_THREAD* thread;

    ListDictionary_Lock(thread_list);

    thread = ListDictionary_GetItemValue(thread_list, &tid);

    WINPR_ASSERT(thread);

    thread->exited = TRUE;

    thread->dwExitCode = dwExitCode;

#if defined(WITH_DEBUG_THREADS)

    thread->exit_stack = winpr_backtrace(20);

#endif

    ListDictionary_Unlock(thread_list);

    set_event(thread);

    rc = thread->dwExitCode;

    if (thread->detached || !thread->started)

      cleanup_handle(thread);

    pthread_exit((void*)(size_t)rc);

  }

#else

  WINPR_UNUSED(dwExitCode);

#endif

}

BOOL GetExitCodeThread(HANDLE hThread, LPDWORD lpExitCode)

{

  ULONG Type;

  WINPR_HANDLE* Object;

  WINPR_THREAD* thread;

  if (!winpr_Handle_GetInfo(hThread, &Type, &Object) || Object->Type != HANDLE_TYPE_THREAD)

  {

    WLog_ERR(TAG, "hThread is not a thread");

    SetLastError(ERROR_INVALID_PARAMETER);

    return FALSE;

  }

  thread = (WINPR_THREAD*)Object;

  *lpExitCode = thread->dwExitCode;

  return TRUE;

}

WINPR_THREAD* winpr_GetCurrentThread(VOID)

{

  WINPR_THREAD* ret;

  InitOnceExecuteOnce(&threads_InitOnce, initializeThreads, NULL, NULL);

  if (mainThreadId == pthread_self())

    return (HANDLE)&mainThread;

  ret = TlsGetValue(currentThreadTlsIndex);

  return ret;

}

HANDLE _GetCurrentThread(VOID)

{

  return (HANDLE)winpr_GetCurrentThread();

}

DWORD GetCurrentThreadId(VOID)

{

  pthread_t tid;

  tid = pthread_self();

  /* Since pthread_t can be 64-bits on some systems, take just the    */

  /* lower 32-bits of it for the thread ID returned by this function. */

  return (DWORD)tid & 0xffffffffUL;

}

typedef struct

{

  WINPR_APC_ITEM apc;

  PAPCFUNC completion;

  ULONG_PTR completionArg;

} UserApcItem;

static void userAPC(LPVOID arg)

{

  UserApcItem* userApc = (UserApcItem*)arg;

  userApc->completion(userApc->completionArg);

  userApc->apc.markedForRemove = TRUE;

}

DWORD QueueUserAPC(PAPCFUNC pfnAPC, HANDLE hThread, ULONG_PTR dwData)

{

  ULONG Type;

  WINPR_HANDLE* Object;

  WINPR_APC_ITEM* apc;

  UserApcItem* apcItem;

  if (!pfnAPC)

    return 1;

  if (!winpr_Handle_GetInfo(hThread, &Type, &Object) || Object->Type != HANDLE_TYPE_THREAD)

  {

    WLog_ERR(TAG, "hThread is not a thread");

    SetLastError(ERROR_INVALID_PARAMETER);

    return (DWORD)0;

  }

  apcItem = calloc(1, sizeof(*apcItem));

  if (!apcItem)

  {

    SetLastError(ERROR_INVALID_PARAMETER);

    return (DWORD)0;

  }

  apc = &apcItem->apc;

  apc->type = APC_TYPE_USER;

  apc->markedForFree = TRUE;

  apc->alwaysSignaled = TRUE;

  apc->completion = userAPC;

  apc->completionArgs = apc;

  apcItem->completion = pfnAPC;

  apcItem->completionArg = dwData;

  apc_register(hThread, apc);

  return 1;

}

DWORD ResumeThread(HANDLE hThread)

{

  ULONG Type;

  WINPR_HANDLE* Object;

  WINPR_THREAD* thread;

  if (!winpr_Handle_GetInfo(hThread, &Type, &Object) || Object->Type != HANDLE_TYPE_THREAD)

  {

    WLog_ERR(TAG, "hThread is not a thread");

    SetLastError(ERROR_INVALID_PARAMETER);

    return (DWORD)-1;

  }

  thread = (WINPR_THREAD*)Object;

  if (!run_mutex_fkt(pthread_mutex_lock, &thread->mutex))

    return (DWORD)-1;

  if (!thread->started)

  {

    if (!winpr_StartThread(thread))

    {

      run_mutex_fkt(pthread_mutex_checked_unlock, &thread->mutex);

      return (DWORD)-1;

    }

  }

  else

    WLog_WARN(TAG, "Thread already started!");

  if (!run_mutex_fkt(pthread_mutex_checked_unlock, &thread->mutex))

    return (DWORD)-1;

  return 0;

}

DWORD SuspendThread(HANDLE hThread)

{

  WLog_ERR(TAG, "not implemented");

  SetLastError(ERROR_CALL_NOT_IMPLEMENTED);

  return (DWORD)-1;

}

BOOL SwitchToThread(VOID)

{

  /**

   * Note: on some operating systems sched_yield is a stub returning -1.

   * usleep should at least trigger a context switch if any thread is waiting.

   */

  if (sched_yield() != 0)

    usleep(1);