blob: 859cc2bf8e7ca6be4f20aecb806d35723d86e220 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
|
/* $OpenBSD: uthread_cancel.c,v 1.16 2007/04/27 19:44:48 kurt Exp $ */
/*
* David Leonard <d@openbsd.org>, 1999. Public domain.
*/
#include <errno.h>
#include <pthread.h>
#include "pthread_private.h"
static void finish_cancellation(struct pthread *);
int
pthread_cancel(pthread_t pthread)
{
int ret;
if ((ret = _find_thread(pthread)) != 0) {
/* NOTHING */
} else if (pthread->state == PS_DEAD || pthread->state == PS_DEADLOCK
|| (pthread->flags & PTHREAD_EXITING) != 0) {
ret = 0;
} else {
/* Protect the scheduling queues: */
_thread_kern_sig_defer();
if (((pthread->cancelflags & PTHREAD_CANCEL_DISABLE) != 0) ||
(((pthread->cancelflags & PTHREAD_CANCEL_ASYNCHRONOUS) == 0) &&
((pthread->cancelflags & PTHREAD_AT_CANCEL_POINT) == 0)))
/* Just mark it for cancellation: */
pthread->cancelflags |= PTHREAD_CANCELLING;
else {
/*
* Check if we need to kick it back into the
* run queue:
*/
switch (pthread->state) {
case PS_RUNNING:
/* No need to resume: */
pthread->cancelflags |= PTHREAD_CANCELLING;
break;
case PS_SPINBLOCK:
case PS_FDR_WAIT:
case PS_FDW_WAIT:
case PS_POLL_WAIT:
case PS_SELECT_WAIT:
/* Remove these threads from the work queue: */
if ((pthread->flags & PTHREAD_FLAGS_IN_WORKQ)
!= 0)
PTHREAD_WORKQ_REMOVE(pthread);
/* Fall through: */
case PS_SIGTHREAD:
case PS_SLEEP_WAIT:
case PS_WAIT_WAIT:
case PS_SIGSUSPEND:
case PS_SIGWAIT:
/* Interrupt and resume: */
pthread->interrupted = 1;
pthread->cancelflags |= PTHREAD_CANCELLING;
PTHREAD_NEW_STATE(pthread,PS_RUNNING);
break;
case PS_JOIN:
/*
* Disconnect the thread from the joinee:
*/
if (pthread->join_status.thread != NULL) {
pthread->join_status.thread->joiner
= NULL;
pthread->join_status.thread = NULL;
}
pthread->cancelflags |= PTHREAD_CANCELLING;
PTHREAD_NEW_STATE(pthread, PS_RUNNING);
break;
case PS_SUSPENDED:
if (pthread->suspended == SUSP_NO ||
pthread->suspended == SUSP_YES ||
pthread->suspended == SUSP_JOIN ||
pthread->suspended == SUSP_NOWAIT) {
/*
* This thread isn't in any scheduling
* queues; just change it's state:
*/
pthread->cancelflags |=
PTHREAD_CANCELLING;
PTHREAD_SET_STATE(pthread, PS_RUNNING);
break;
}
/* FALLTHROUGH */
case PS_MUTEX_WAIT:
case PS_COND_WAIT:
case PS_FDLR_WAIT:
case PS_FDLW_WAIT:
case PS_FILE_WAIT:
/*
* Threads in these states may be in queues.
* In order to preserve queue integrity, the
* cancelled thread must remove itself from the
* queue. Mark the thread as interrupted and
* needing cancellation, and set the state to
* running. When the thread resumes, it will
* remove itself from the queue and call the
* cancellation completion routine.
*/
pthread->interrupted = 1;
pthread->cancelflags |= PTHREAD_CANCEL_NEEDED;
PTHREAD_NEW_STATE(pthread,PS_RUNNING);
pthread->continuation = finish_cancellation;
break;
case PS_DEAD:
case PS_DEADLOCK:
case PS_STATE_MAX:
/* Ignore - only here to silence -Wall: */
break;
}
}
/* Unprotect the scheduling queues: */
_thread_kern_sig_undefer();
ret = 0;
}
return (ret);
}
int
pthread_setcancelstate(int state, int *oldstate)
{
struct pthread *curthread = _get_curthread();
int ostate;
int ret;
ostate = curthread->cancelflags & PTHREAD_CANCEL_DISABLE;
switch (state) {
case PTHREAD_CANCEL_ENABLE:
if (oldstate != NULL)
*oldstate = ostate;
curthread->cancelflags &= ~PTHREAD_CANCEL_DISABLE;
if ((curthread->cancelflags & PTHREAD_CANCEL_ASYNCHRONOUS) != 0)
pthread_testcancel();
ret = 0;
break;
case PTHREAD_CANCEL_DISABLE:
if (oldstate != NULL)
*oldstate = ostate;
curthread->cancelflags |= PTHREAD_CANCEL_DISABLE;
ret = 0;
break;
default:
ret = EINVAL;
}
return (ret);
}
int
pthread_setcanceltype(int type, int *oldtype)
{
struct pthread *curthread = _get_curthread();
int otype;
int ret;
otype = curthread->cancelflags & PTHREAD_CANCEL_ASYNCHRONOUS;
switch (type) {
case PTHREAD_CANCEL_ASYNCHRONOUS:
if (oldtype != NULL)
*oldtype = otype;
curthread->cancelflags |= PTHREAD_CANCEL_ASYNCHRONOUS;
pthread_testcancel();
ret = 0;
break;
case PTHREAD_CANCEL_DEFERRED:
if (oldtype != NULL)
*oldtype = otype;
curthread->cancelflags &= ~PTHREAD_CANCEL_ASYNCHRONOUS;
ret = 0;
break;
default:
ret = EINVAL;
}
return (ret);
}
void
pthread_testcancel(void)
{
struct pthread *curthread = _get_curthread();
if (((curthread->cancelflags & PTHREAD_CANCEL_DISABLE) == 0) &&
((curthread->cancelflags & PTHREAD_CANCELLING) != 0) &&
((curthread->flags & PTHREAD_EXITING) == 0)) {
/*
* It is possible for this thread to be swapped out
* while performing cancellation; do not allow it
* to be cancelled again.
*/
curthread->cancelflags &= ~PTHREAD_CANCELLING;
#ifdef notyet
_thread_exit_cleanup();
#endif
pthread_exit(PTHREAD_CANCELED);
PANIC("cancel");
}
}
void
_thread_enter_cancellation_point(void)
{
struct pthread *curthread = _get_curthread();
/* Look for a cancellation before we block: */
pthread_testcancel();
curthread->cancelflags |= PTHREAD_AT_CANCEL_POINT;
}
void
_thread_leave_cancellation_point(void)
{
struct pthread *curthread = _get_curthread();
curthread->cancelflags &= ~PTHREAD_AT_CANCEL_POINT;
/* Look for a cancellation after we unblock: */
pthread_testcancel();
}
static void
finish_cancellation(struct pthread *curthread)
{
curthread->continuation = NULL;
curthread->interrupted = 0;
if ((curthread->cancelflags & PTHREAD_CANCEL_NEEDED) != 0) {
curthread->cancelflags &= ~PTHREAD_CANCEL_NEEDED;
#ifdef notyet
_thread_exit_cleanup();
#endif
pthread_exit(PTHREAD_CANCELED);
}
}
|
