/* * pthread_cancel.c * * Description: * POSIX thread functions related to thread cancellation. * * -------------------------------------------------------------------------- * *      Pthreads-win32 - POSIX Threads Library for Win32 *      Copyright(C) 1998 John E. Bossom *      Copyright(C) 1999,2005 Pthreads-win32 contributors *  *      Contact Email: rpj@callisto.canberra.edu.au *  *      The current list of contributors is contained *      in the file CONTRIBUTORS included with the source *      code distribution. The list can also be seen at the *      following World Wide Web location: *      http://sources.redhat.com/pthreads-win32/contributors.html *  *      This library is free software; you can redistribute it and/or *      modify it under the terms of the GNU Lesser General Public *      License as published by the Free Software Foundation; either *      version 2 of the License, or (at your option) any later version. *  *      This library is distributed in the hope that it will be useful, *      but WITHOUT ANY WARRANTY; without even the implied warranty of *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU *      Lesser General Public License for more details. *  *      You should have received a copy of the GNU Lesser General Public *      License along with this library in the file COPYING.LIB; *      if not, write to the Free Software Foundation, Inc., *      59 Temple Place - Suite 330, Boston, MA 02111-1307, USA */#include "pthread.h"#include "implement.h"#if defined(_M_IX86) || defined(_X86_)#define PTW32_PROGCTR(Context)  ((Context).Eip)#endif#if defined(_MIPS_)#define PTW32_PROGCTR(Context)  ((Context).Fir)#endif#if defined(_ALPHA_)#define PTW32_PROGCTR(Context)  ((Context).Fir)#endif#if defined(_PPC_)#define PTW32_PROGCTR(Context)  ((Context).Iar)#endif#if defined(_AMD64_)#define PTW32_PROGCTR(Context)  ((Context).Rip)#endif#if !defined(PTW32_PROGCTR)#error Module contains CPU-specific code; modify and recompile.#endifstatic voidptw32_cancel_self (void){  ptw32_throw (PTW32_EPS_CANCEL);  /* Never reached */}static void CALLBACKptw32_cancel_callback (DWORD unused){  ptw32_throw (PTW32_EPS_CANCEL);  /* Never reached */}/* * ptw32_RegisterCancelation() - * Must have args of same type as QueueUserAPCEx because this function * is a substitute for QueueUserAPCEx if it's not available. */DWORDptw32_RegisterCancelation (PAPCFUNC unused1, HANDLE threadH, DWORD unused2){  CONTEXT context;  context.ContextFlags = CONTEXT_CONTROL;  GetThreadContext (threadH, &context);  PTW32_PROGCTR (context) = (DWORD_PTR) ptw32_cancel_self;  SetThreadContext (threadH, &context);  return 0;}intpthread_cancel (pthread_t thread)     /*      * ------------------------------------------------------      * DOCPUBLIC      *      This function requests cancellation of 'thread'.      *      * PARAMETERS      *      thread      *              reference to an instance of pthread_t      *      *      * DESCRIPTION      *      This function requests cancellation of 'thread'.      *      NOTE: cancellation is asynchronous; use pthread_join to      *                wait for termination of 'thread' if necessary.      *      * RESULTS      *              0               successfully requested cancellation,      *              ESRCH           no thread found corresponding to 'thread',      *              ENOMEM          implicit self thread create failed.      * ------------------------------------------------------      */{  int result;  int cancel_self;  pthread_t self;  ptw32_thread_t * tp;  result = pthread_kill (thread, 0);  if (0 != result)    {      return result;    }  if ((self = pthread_self ()).p == NULL)    {      return ENOMEM;    };  /*   * FIXME!!   *   * Can a thread cancel itself?   *   * The standard doesn't   * specify an error to be returned if the target   * thread is itself.   *   * If it may, then we need to ensure that a thread can't   * deadlock itself trying to cancel itself asyncronously   * (pthread_cancel is required to be an async-cancel   * safe function).   */  cancel_self = pthread_equal (thread, self);  tp = (ptw32_thread_t *) thread.p;  /*   * Lock for async-cancel safety.   */  (void) pthread_mutex_lock (&tp->cancelLock);  if (tp->cancelType == PTHREAD_CANCEL_ASYNCHRONOUS      && tp->cancelState == PTHREAD_CANCEL_ENABLE      && tp->state < PThreadStateCanceling)    {      if (cancel_self)	{	  tp->state = PThreadStateCanceling;	  tp->cancelState = PTHREAD_CANCEL_DISABLE;	  (void) pthread_mutex_unlock (&tp->cancelLock);	  ptw32_throw (PTW32_EPS_CANCEL);	  /* Never reached */	}      else	{	  HANDLE threadH = tp->threadH;	  SuspendThread (threadH);	  if (WaitForSingleObject (threadH, 0) == WAIT_TIMEOUT)	    {	      tp->state = PThreadStateCanceling;	      tp->cancelState = PTHREAD_CANCEL_DISABLE;	      /*	       * If alertdrv and QueueUserAPCEx is available then the following	       * will result in a call to QueueUserAPCEx with the args given, otherwise	       * this will result in a call to ptw32_RegisterCancelation and only	       * the threadH arg will be used.	       */	      ptw32_register_cancelation (ptw32_cancel_callback, threadH, 0);	      (void) pthread_mutex_unlock (&tp->cancelLock);	      ResumeThread (threadH);	    }	}    }  else    {      /*       * Set for deferred cancellation.       */      if (tp->state < PThreadStateCancelPending)	{	  tp->state = PThreadStateCancelPending;	  if (!SetEvent (tp->cancelEvent))	    {	      result = ESRCH;	    }	}      else if (tp->state >= PThreadStateCanceling)	{	  result = ESRCH;	}      (void) pthread_mutex_unlock (&tp->cancelLock);    }  return (result);}