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/*
* 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"
#include "context.h"
static void
ptw32_cancel_self (void)
{
ptw32_throw (PTW32_EPS_CANCEL);
/* Never reached */
}
static void CALLBACK
ptw32_cancel_callback (ULONG_PTR 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.
*/
DWORD
ptw32_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;
}
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;
ptw32_thread_t * tp;
ptw32_mcs_local_node_t stateLock;
result = pthread_kill (thread, 0);
if (0 != result)
{
return result;
}
if ((self = pthread_self ()).p == NULL)
{
return ENOMEM;
};
/*
* For self cancellation we need to ensure that a thread can't
* deadlock itself trying to cancel itself asynchronously
* (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.
*/
ptw32_mcs_lock_acquire (&tp->stateLock, &stateLock);
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;
ptw32_mcs_lock_release (&stateLock);
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 ((PAPCFUNC)ptw32_cancel_callback, threadH, 0);
ptw32_mcs_lock_release (&stateLock);
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;
}
ptw32_mcs_lock_release (&stateLock);
}
return (result);
}
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