1 /*
2  * Copyright (c) 2005, David Xu<davidxu@freebsd.org>
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice unmodified, this list of conditions, and the following
10  *    disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25  *
26  * $DragonFly: src/lib/libthread_xu/thread/thr_cancel.c,v 1.4 2006/04/06 13:03:09 davidxu Exp $
27  */
28 
29 #include "namespace.h"
30 #include <machine/tls.h>
31 #include <pthread.h>
32 #include "un-namespace.h"
33 
34 #include "thr_private.h"
35 
36 int _pthread_setcanceltype(int type, int *oldtype);
37 
38 int
39 _pthread_cancel(pthread_t pthread)
40 {
41 	struct pthread *curthread = tls_get_curthread();
42 	int oldval, newval = 0;
43 	int oldtype;
44 	int ret;
45 
46 	/*
47 	 * POSIX says _pthread_cancel should be async cancellation safe,
48 	 * so we temporarily disable async cancellation.
49 	 */
50 	_pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED, &oldtype);
51 	if ((ret = _thr_ref_add(curthread, pthread, 0)) != 0) {
52 		_pthread_setcanceltype(oldtype, NULL);
53 		return (ret);
54 	}
55 
56 	do {
57 		oldval = pthread->cancelflags;
58 		if (oldval & THR_CANCEL_NEEDED)
59 			break;
60 		newval = oldval | THR_CANCEL_NEEDED;
61 	} while (!atomic_cmpset_acq_int(&pthread->cancelflags, oldval, newval));
62 
63 	if (!(oldval & THR_CANCEL_NEEDED) && SHOULD_ASYNC_CANCEL(newval))
64 		_thr_send_sig(pthread, SIGCANCEL);
65 
66 	_thr_ref_delete(curthread, pthread);
67 	_pthread_setcanceltype(oldtype, NULL);
68 	return (0);
69 }
70 
71 static inline void
72 testcancel(struct pthread *curthread)
73 {
74 	int newval;
75 
76 	newval = curthread->cancelflags;
77 	if (SHOULD_CANCEL(newval))
78 		_pthread_exit(PTHREAD_CANCELED);
79 }
80 
81 int
82 _pthread_setcancelstate(int state, int *oldstate)
83 {
84 	struct pthread *curthread = tls_get_curthread();
85 	int oldval, ret;
86 
87 	oldval = curthread->cancelflags;
88 	if (oldstate != NULL)
89 		*oldstate = ((oldval & THR_CANCEL_DISABLE) ?
90 		    PTHREAD_CANCEL_DISABLE : PTHREAD_CANCEL_ENABLE);
91 	switch (state) {
92 	case PTHREAD_CANCEL_DISABLE:
93 		atomic_set_int(&curthread->cancelflags, THR_CANCEL_DISABLE);
94 		ret = 0;
95 		break;
96 	case PTHREAD_CANCEL_ENABLE:
97 		atomic_clear_int(&curthread->cancelflags, THR_CANCEL_DISABLE);
98 		testcancel(curthread);
99 		ret = 0;
100 		break;
101 	default:
102 		ret = EINVAL;
103 	}
104 
105 	return (ret);
106 }
107 
108 int
109 _pthread_setcanceltype(int type, int *oldtype)
110 {
111 	struct pthread	*curthread = tls_get_curthread();
112 	int oldval, ret;
113 
114 	oldval = curthread->cancelflags;
115 	if (oldtype != NULL)
116 		*oldtype = ((oldval & THR_CANCEL_AT_POINT) ?
117 				 PTHREAD_CANCEL_ASYNCHRONOUS :
118 				 PTHREAD_CANCEL_DEFERRED);
119 	switch (type) {
120 	case PTHREAD_CANCEL_ASYNCHRONOUS:
121 		atomic_set_int(&curthread->cancelflags, THR_CANCEL_AT_POINT);
122 		testcancel(curthread);
123 		ret = 0;
124 		break;
125 	case PTHREAD_CANCEL_DEFERRED:
126 		atomic_clear_int(&curthread->cancelflags, THR_CANCEL_AT_POINT);
127 		ret = 0;
128 		break;
129 	default:
130 		ret = EINVAL;
131 	}
132 
133 	return (ret);
134 }
135 
136 void
137 _pthread_testcancel(void)
138 {
139 	testcancel(tls_get_curthread());
140 }
141 
142 int
143 _thr_cancel_enter(struct pthread *curthread)
144 {
145 	int oldval;
146 
147 	oldval = curthread->cancelflags;
148 	if (!(oldval & THR_CANCEL_AT_POINT)) {
149 		atomic_set_int(&curthread->cancelflags, THR_CANCEL_AT_POINT);
150 		testcancel(curthread);
151 	}
152 	return (oldval);
153 }
154 
155 void
156 _thr_cancel_leave(struct pthread *curthread, int previous)
157 {
158 	if (!(previous & THR_CANCEL_AT_POINT))
159 		atomic_clear_int(&curthread->cancelflags, THR_CANCEL_AT_POINT);
160 }
161 
162 __strong_reference(_pthread_cancel, pthread_cancel);
163 __strong_reference(_pthread_setcancelstate, pthread_setcancelstate);
164 __strong_reference(_pthread_setcanceltype, pthread_setcanceltype);
165 __strong_reference(_pthread_testcancel, pthread_testcancel);
166 
167