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/* $OpenBSD: cancel.h,v 1.4 2017/04/20 17:16:32 visa Exp $ */
/*
* Copyright (c) 2015 Philip Guenther <guenther@openbsd.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#ifndef _CANCEL_H_
#define _CANCEL_H_
#include <tib.h>
#include "thread_private.h"
__BEGIN_HIDDEN_DECLS
/* process a cancel request at a cancel point */
__dead void _thread_canceled(void);
__END_HIDDEN_DECLS
#if defined(__LIBC__) && !defined(TCB_HAVE_MD_GET)
/*
* Override TIB_GET macro to use the caching callback
*/
#undef TIB_GET
#define TIB_GET() TCB_TO_TIB(_thread_cb.tc_tcb())
#endif
#define PREP_CANCEL_POINT(tib) \
int _cantcancel = (tib)->tib_cantcancel
#define ENTER_CANCEL_POINT_INNER(tib, can_cancel, delay) \
if (_cantcancel == 0) { \
(tib)->tib_cancel_point = (delay) ? \
CANCEL_POINT_DELAYED : CANCEL_POINT; \
if (can_cancel) { \
__asm volatile("":::"memory"); \
if (__predict_false((tib)->tib_canceled)) \
_thread_canceled(); \
} \
}
#define LEAVE_CANCEL_POINT_INNER(tib, can_cancel) \
if (_cantcancel == 0) { \
(tib)->tib_cancel_point = 0; \
if (can_cancel) { \
__asm volatile("":::"memory"); \
if (__predict_false((tib)->tib_canceled)) \
_thread_canceled(); \
} \
}
/*
* Enter or leave a cancelation point, optionally processing pending
* cancelation requests. Note that ENTER_CANCEL_POINT opens a block
* and LEAVE_CANCEL_POINT must close that same block.
*/
#define ENTER_CANCEL_POINT(can_cancel) \
{ \
struct tib *_tib = TIB_GET(); \
PREP_CANCEL_POINT(_tib); \
ENTER_CANCEL_POINT_INNER(_tib, can_cancel, 0)
#define LEAVE_CANCEL_POINT(can_cancel) \
LEAVE_CANCEL_POINT_INNER(_tib, can_cancel); \
}
#endif /* _CANCEL_H_ */
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