1 /* $OpenBSD: cancel.h,v 1.1 2016/05/07 19:05:22 guenther Exp $ */ 2 /* 3 * Copyright (c) 2015 Philip Guenther <guenther@openbsd.org> 4 * 5 * Permission to use, copy, modify, and distribute this software for any 6 * purpose with or without fee is hereby granted, provided that the above 7 * copyright notice and this permission notice appear in all copies. 8 * 9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 16 */ 17 18 #ifndef _CANCEL_H_ 19 #define _CANCEL_H_ 20 21 #include <tib.h> 22 #include "thread_private.h" 23 24 __BEGIN_HIDDEN_DECLS 25 /* process a cancel request at a cancel point */ 26 __dead void _thread_canceled(void); 27 __END_HIDDEN_DECLS 28 29 #ifdef LIBC 30 /* 31 * Redirect macros that would use the syscall to instead use our callback 32 */ 33 #define __get_tcb() _thread_cb.tc_tcb() 34 #endif 35 36 #define PREP_CANCEL_POINT(tib) \ 37 int _cantcancel = (tib)->tib_cantcancel 38 39 #define ENTER_CANCEL_POINT_INNER(tib, can_cancel, delay) \ 40 if (_cantcancel == 0) { \ 41 (tib)->tib_cancel_point = (delay) ? \ 42 CANCEL_POINT_DELAYED : CANCEL_POINT; \ 43 if (can_cancel) { \ 44 __asm volatile("":::"memory"); \ 45 if (__predict_false((tib)->tib_canceled)) \ 46 _thread_canceled(); \ 47 } \ 48 } 49 50 #define LEAVE_CANCEL_POINT_INNER(tib, can_cancel) \ 51 if (_cantcancel == 0) { \ 52 (tib)->tib_cancel_point = 0; \ 53 if (can_cancel) { \ 54 __asm volatile("":::"memory"); \ 55 if (__predict_false((tib)->tib_canceled)) \ 56 _thread_canceled(); \ 57 } \ 58 } 59 60 /* 61 * Enter or leave a cancelation point, optionally processing pending 62 * cancelation requests. Note that ENTER_CANCEL_POINT opens a block 63 * and LEAVE_CANCEL_POINT must close that same block. 64 */ 65 #define ENTER_CANCEL_POINT(can_cancel) \ 66 { \ 67 struct tib *_tib = TIB_GET(); \ 68 PREP_CANCEL_POINT(_tib); \ 69 ENTER_CANCEL_POINT_INNER(_tib, can_cancel, 0) 70 71 #define LEAVE_CANCEL_POINT(can_cancel) \ 72 LEAVE_CANCEL_POINT_INNER(_tib, can_cancel); \ 73 } 74 75 #endif /* _CANCEL_H_ */ 76