xref: /freebsd/lib/libthr/thread/thr_cancel.c (revision f1951fd745b894fe6586c298874af98544a5e272)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2005, David Xu <davidxu@freebsd.org>
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice unmodified, this list of conditions, and the following
12  *    disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27  */
28 
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31 
32 #include "namespace.h"
33 #include <pthread.h>
34 #include "un-namespace.h"
35 
36 #include "thr_private.h"
37 
38 __weak_reference(_pthread_cancel, pthread_cancel);
39 __weak_reference(_pthread_setcancelstate, pthread_setcancelstate);
40 __weak_reference(_pthread_setcanceltype, pthread_setcanceltype);
41 __weak_reference(_pthread_testcancel, pthread_testcancel);
42 
43 static inline void
44 testcancel(struct pthread *curthread)
45 {
46 	if (__predict_false(SHOULD_CANCEL(curthread) &&
47 	    !THR_IN_CRITICAL(curthread)))
48 		_pthread_exit(PTHREAD_CANCELED);
49 }
50 
51 void
52 _thr_testcancel(struct pthread *curthread)
53 {
54 	testcancel(curthread);
55 }
56 
57 int
58 _pthread_cancel(pthread_t pthread)
59 {
60 	struct pthread *curthread = _get_curthread();
61 	int ret;
62 
63 	/*
64 	 * POSIX says _pthread_cancel should be async cancellation safe.
65 	 * _thr_find_thread and THR_THREAD_UNLOCK will enter and leave critical
66 	 * region automatically.
67 	 */
68 	if ((ret = _thr_find_thread(curthread, pthread, 0)) == 0) {
69 		if (!pthread->cancel_pending) {
70 			pthread->cancel_pending = 1;
71 			if (pthread->state != PS_DEAD)
72 				_thr_send_sig(pthread, SIGCANCEL);
73 		}
74 		THR_THREAD_UNLOCK(curthread, pthread);
75 	}
76 	return (ret);
77 }
78 
79 int
80 _pthread_setcancelstate(int state, int *oldstate)
81 {
82 	struct pthread *curthread = _get_curthread();
83 	int oldval;
84 
85 	oldval = curthread->cancel_enable;
86 	switch (state) {
87 	case PTHREAD_CANCEL_DISABLE:
88 		curthread->cancel_enable = 0;
89 		break;
90 	case PTHREAD_CANCEL_ENABLE:
91 		curthread->cancel_enable = 1;
92 		if (curthread->cancel_async)
93 			testcancel(curthread);
94 		break;
95 	default:
96 		return (EINVAL);
97 	}
98 
99 	if (oldstate) {
100 		*oldstate = oldval ? PTHREAD_CANCEL_ENABLE :
101 			PTHREAD_CANCEL_DISABLE;
102 	}
103 	return (0);
104 }
105 
106 int
107 _pthread_setcanceltype(int type, int *oldtype)
108 {
109 	struct pthread	*curthread = _get_curthread();
110 	int oldval;
111 
112 	oldval = curthread->cancel_async;
113 	switch (type) {
114 	case PTHREAD_CANCEL_ASYNCHRONOUS:
115 		curthread->cancel_async = 1;
116 		testcancel(curthread);
117 		break;
118 	case PTHREAD_CANCEL_DEFERRED:
119 		curthread->cancel_async = 0;
120 		break;
121 	default:
122 		return (EINVAL);
123 	}
124 
125 	if (oldtype) {
126 		*oldtype = oldval ? PTHREAD_CANCEL_ASYNCHRONOUS :
127 		 	PTHREAD_CANCEL_DEFERRED;
128 	}
129 	return (0);
130 }
131 
132 void
133 _pthread_testcancel(void)
134 {
135 	struct pthread *curthread;
136 
137 	_thr_check_init();
138 	curthread = _get_curthread();
139 	testcancel(curthread);
140 }
141 
142 void
143 _thr_cancel_enter(struct pthread *curthread)
144 {
145 	curthread->cancel_point = 1;
146 	testcancel(curthread);
147 }
148 
149 void
150 _thr_cancel_enter2(struct pthread *curthread, int maycancel)
151 {
152 	curthread->cancel_point = 1;
153 	if (__predict_false(SHOULD_CANCEL(curthread) &&
154 	    !THR_IN_CRITICAL(curthread))) {
155 		if (!maycancel)
156 			thr_wake(curthread->tid);
157 		else
158 			_pthread_exit(PTHREAD_CANCELED);
159 	}
160 }
161 
162 void
163 _thr_cancel_leave(struct pthread *curthread, int maycancel)
164 {
165 	curthread->cancel_point = 0;
166 	if (__predict_false(SHOULD_CANCEL(curthread) &&
167 	    !THR_IN_CRITICAL(curthread) && maycancel))
168 		_pthread_exit(PTHREAD_CANCELED);
169 }
170 
171 void
172 _pthread_cancel_enter(int maycancel)
173 {
174 	_thr_cancel_enter2(_get_curthread(), maycancel);
175 }
176 
177 void
178 _pthread_cancel_leave(int maycancel)
179 {
180 	_thr_cancel_leave(_get_curthread(), maycancel);
181 }
182