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/*
* cancel_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) 1999,2002 Pthreads-win32 contributors
*
* Contact Email: rpj@ise.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(PTW32_PROGCTR)
#error Module contains CPU-specific code; modify and recompile.
#endif
static INLINE void
ptw32_cancel_self(void)
{
ptw32_throw(PTW32_EPS_CANCEL);
/* Never reached */
}
int
pthread_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;
if (thread == NULL )
{
return ESRCH;
}
result = 0;
if ((self = pthread_self()) == 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);
/*
* Lock for async-cancel safety.
*/
(void) pthread_mutex_lock(&thread->cancelLock);
if (thread->cancelType == PTHREAD_CANCEL_ASYNCHRONOUS
&& thread->cancelState == PTHREAD_CANCEL_ENABLE
&& thread->state < PThreadStateCanceling )
{
if (cancel_self)
{
thread->state = PThreadStateCanceling;
thread->cancelState = PTHREAD_CANCEL_DISABLE;
(void) pthread_mutex_unlock(&thread->cancelLock);
ptw32_throw(PTW32_EPS_CANCEL);
/* Never reached */
}
else
{
HANDLE threadH = thread->threadH;
SuspendThread(threadH);
if (WaitForSingleObject(threadH, 0) == WAIT_TIMEOUT )
{
CONTEXT context;
thread->state = PThreadStateCanceling;
thread->cancelState = PTHREAD_CANCEL_DISABLE;
context.ContextFlags = CONTEXT_CONTROL;
GetThreadContext(threadH, &context);
PTW32_PROGCTR(context) = (DWORD) ptw32_cancel_self;
SetThreadContext(threadH, &context);
(void) pthread_mutex_unlock(&thread->cancelLock);
ResumeThread(threadH);
}
}
}
else
{
/*
* Set for deferred cancellation.
*/
if ( thread->state >= PThreadStateCanceling
|| !SetEvent (thread->cancelEvent))
{
result = ESRCH;
}
(void) pthread_mutex_unlock(&thread->cancelLock);
}
return (result);
}
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