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ee9dd372 TT |
1 | // posix-threads.cc - interface between libjava and POSIX threads. |
2 | ||
304daac5 | 3 | /* Copyright (C) 1998, 1999, 2000 Free Software Foundation |
ee9dd372 TT |
4 | |
5 | This file is part of libgcj. | |
6 | ||
7 | This software is copyrighted work licensed under the terms of the | |
8 | Libgcj License. Please consult the file "LIBGCJ_LICENSE" for | |
9 | details. */ | |
10 | ||
11 | // TO DO: | |
12 | // * Document signal handling limitations | |
13 | ||
14 | #include <config.h> | |
15 | ||
16 | // If we're using the Boehm GC, then we need to override some of the | |
17 | // thread primitives. This is fairly gross. | |
18 | #ifdef HAVE_BOEHM_GC | |
19 | extern "C" | |
20 | { | |
8fbe2d95 | 21 | #include <gcconfig.h> |
ee9dd372 TT |
22 | #include <gc.h> |
23 | }; | |
24 | #endif /* HAVE_BOEHM_GC */ | |
25 | ||
26 | #include <stdlib.h> | |
27 | #include <time.h> | |
28 | #include <signal.h> | |
d55d01bd | 29 | #include <errno.h> |
43cbc943 | 30 | #include <limits.h> |
ee9dd372 | 31 | |
27e934d8 | 32 | #include <gcj/cni.h> |
ee9dd372 TT |
33 | #include <jvm.h> |
34 | #include <java/lang/Thread.h> | |
35 | #include <java/lang/System.h> | |
43cbc943 BM |
36 | #include <java/lang/Long.h> |
37 | #include <java/lang/OutOfMemoryError.h> | |
ee9dd372 TT |
38 | |
39 | // This is used to implement thread startup. | |
40 | struct starter | |
41 | { | |
42 | _Jv_ThreadStartFunc *method; | |
ee9dd372 TT |
43 | _Jv_Thread_t *data; |
44 | }; | |
45 | ||
46 | // This is the key used to map from the POSIX thread value back to the | |
47 | // Java object representing the thread. The key is global to all | |
48 | // threads, so it is ok to make it a global here. | |
49 | pthread_key_t _Jv_ThreadKey; | |
50 | ||
fd59e3a0 TT |
51 | // This is the key used to map from the POSIX thread value back to the |
52 | // _Jv_Thread_t* representing the thread. | |
53 | pthread_key_t _Jv_ThreadDataKey; | |
54 | ||
ee9dd372 TT |
55 | // We keep a count of all non-daemon threads which are running. When |
56 | // this reaches zero, _Jv_ThreadWait returns. | |
57 | static pthread_mutex_t daemon_mutex; | |
58 | static pthread_cond_t daemon_cond; | |
59 | static int non_daemon_count; | |
60 | ||
61 | // The signal to use when interrupting a thread. | |
62 | #ifdef LINUX_THREADS | |
43cbc943 | 63 | // LinuxThreads (prior to glibc 2.1) usurps both SIGUSR1 and SIGUSR2. |
ee9dd372 TT |
64 | # define INTR SIGHUP |
65 | #else /* LINUX_THREADS */ | |
66 | # define INTR SIGUSR2 | |
67 | #endif /* LINUX_THREADS */ | |
68 | ||
69 | // | |
70 | // These are the flags that can appear in _Jv_Thread_t. | |
71 | // | |
72 | ||
73 | // Thread started. | |
74 | #define FLAG_START 0x01 | |
75 | // Thread is daemon. | |
76 | #define FLAG_DAEMON 0x02 | |
77 | ||
78 | \f | |
79 | ||
b834f1fa BM |
80 | // Wait for the condition variable "CV" to be notified. |
81 | // Return values: | |
82 | // 0: the condition was notified, or the timeout expired. | |
83 | // _JV_NOT_OWNER: the thread does not own the mutex "MU". | |
84 | // _JV_INTERRUPTED: the thread was interrupted. Its interrupted flag is set. | |
ee9dd372 TT |
85 | int |
86 | _Jv_CondWait (_Jv_ConditionVariable_t *cv, _Jv_Mutex_t *mu, | |
87 | jlong millis, jint nanos) | |
88 | { | |
b834f1fa BM |
89 | pthread_t self = pthread_self(); |
90 | if (mu->owner != self) | |
91 | return _JV_NOT_OWNER; | |
6e87747b | 92 | |
43cbc943 | 93 | struct timespec ts; |
b834f1fa | 94 | jlong m, startTime; |
6e87747b | 95 | |
b834f1fa | 96 | if (millis > 0 || nanos > 0) |
ee9dd372 | 97 | { |
fd59e3a0 TT |
98 | startTime = java::lang::System::currentTimeMillis(); |
99 | m = millis + startTime; | |
43cbc943 BM |
100 | ts.tv_sec = m / 1000; |
101 | ts.tv_nsec = ((m % 1000) * 1000000) + nanos; | |
102 | } | |
fd59e3a0 | 103 | |
b834f1fa BM |
104 | _Jv_Thread_t *current = _Jv_ThreadCurrentData (); |
105 | java::lang::Thread *current_obj = _Jv_ThreadCurrent (); | |
106 | ||
304daac5 TT |
107 | pthread_mutex_lock (¤t->wait_mutex); |
108 | ||
109 | // Now that we hold the wait mutex, check if this thread has been | |
110 | // interrupted already. | |
111 | if (current_obj->interrupt_flag) | |
112 | { | |
113 | pthread_mutex_unlock (¤t->wait_mutex); | |
114 | return _JV_INTERRUPTED; | |
115 | } | |
116 | ||
b834f1fa BM |
117 | // Add this thread to the cv's wait set. |
118 | current->next = NULL; | |
fd59e3a0 | 119 | |
b834f1fa BM |
120 | if (cv->first == NULL) |
121 | cv->first = current; | |
122 | else | |
123 | for (_Jv_Thread_t *t = cv->first;; t = t->next) | |
124 | { | |
125 | if (t->next == NULL) | |
126 | { | |
127 | t->next = current; | |
128 | break; | |
129 | } | |
130 | } | |
131 | ||
b834f1fa BM |
132 | // Record the current lock depth, so it can be restored when we re-aquire it. |
133 | int count = mu->count; | |
134 | ||
135 | // Release the monitor mutex. | |
136 | mu->count = 0; | |
137 | mu->owner = 0; | |
138 | pthread_mutex_unlock (&mu->mutex); | |
139 | ||
140 | int r = 0; | |
141 | bool done_sleeping = false; | |
142 | ||
143 | while (! done_sleeping) | |
144 | { | |
145 | if (millis == 0 && nanos == 0) | |
146 | r = pthread_cond_wait (¤t->wait_cond, ¤t->wait_mutex); | |
147 | else | |
148 | r = pthread_cond_timedwait (¤t->wait_cond, ¤t->wait_mutex, | |
149 | &ts); | |
e301621d | 150 | |
b834f1fa BM |
151 | // In older glibc's (prior to 2.1.3), the cond_wait functions may |
152 | // spuriously wake up on a signal. Catch that here. | |
153 | if (r != EINTR) | |
154 | done_sleeping = true; | |
155 | } | |
156 | ||
304daac5 | 157 | // Check for an interrupt *before* releasing the wait mutex. |
b834f1fa BM |
158 | jboolean interrupted = current_obj->interrupt_flag; |
159 | ||
160 | pthread_mutex_unlock (¤t->wait_mutex); | |
161 | ||
162 | // Reaquire the monitor mutex, and restore the lock count. | |
163 | pthread_mutex_lock (&mu->mutex); | |
164 | mu->owner = self; | |
165 | mu->count = count; | |
166 | ||
167 | // If we were interrupted, or if a timeout occured, remove ourself from | |
168 | // the cv wait list now. (If we were notified normally, notify() will have | |
169 | // already taken care of this) | |
170 | if (r == ETIMEDOUT || interrupted) | |
171 | { | |
172 | _Jv_Thread_t *prev = NULL; | |
173 | for (_Jv_Thread_t *t = cv->first; t != NULL; t = t->next) | |
43cbc943 | 174 | { |
b834f1fa | 175 | if (t == current) |
fd59e3a0 | 176 | { |
b834f1fa BM |
177 | if (prev != NULL) |
178 | prev->next = t->next; | |
179 | else | |
180 | cv->first = t->next; | |
181 | t->next = NULL; | |
182 | break; | |
fd59e3a0 | 183 | } |
b834f1fa | 184 | prev = t; |
fd59e3a0 | 185 | } |
b834f1fa BM |
186 | if (interrupted) |
187 | return _JV_INTERRUPTED; | |
ee9dd372 | 188 | } |
b834f1fa BM |
189 | |
190 | return 0; | |
ee9dd372 TT |
191 | } |
192 | ||
b834f1fa BM |
193 | int |
194 | _Jv_CondNotify (_Jv_ConditionVariable_t *cv, _Jv_Mutex_t *mu) | |
ee9dd372 | 195 | { |
b834f1fa BM |
196 | if (_Jv_PthreadCheckMonitor (mu)) |
197 | return _JV_NOT_OWNER; | |
ee9dd372 | 198 | |
b834f1fa BM |
199 | _Jv_Thread_t *target; |
200 | _Jv_Thread_t *prev = NULL; | |
ee9dd372 | 201 | |
b834f1fa BM |
202 | for (target = cv->first; target != NULL; target = target->next) |
203 | { | |
204 | pthread_mutex_lock (&target->wait_mutex); | |
ee9dd372 | 205 | |
b834f1fa BM |
206 | if (target->thread_obj->interrupt_flag) |
207 | { | |
208 | // Don't notify a thread that has already been interrupted. | |
209 | pthread_mutex_unlock (&target->wait_mutex); | |
210 | prev = target; | |
211 | continue; | |
212 | } | |
ee9dd372 | 213 | |
b834f1fa BM |
214 | pthread_cond_signal (&target->wait_cond); |
215 | pthread_mutex_unlock (&target->wait_mutex); | |
ee9dd372 | 216 | |
f52c7239 BM |
217 | // Two concurrent notify() calls must not be delivered to the same |
218 | // thread, so remove the target thread from the cv wait list now. | |
b834f1fa BM |
219 | if (prev == NULL) |
220 | cv->first = target->next; | |
221 | else | |
222 | prev->next = target->next; | |
223 | ||
224 | target->next = NULL; | |
225 | ||
226 | break; | |
227 | } | |
ee9dd372 | 228 | |
b834f1fa | 229 | return 0; |
ee9dd372 TT |
230 | } |
231 | ||
232 | int | |
b834f1fa | 233 | _Jv_CondNotifyAll (_Jv_ConditionVariable_t *cv, _Jv_Mutex_t *mu) |
ee9dd372 | 234 | { |
b834f1fa BM |
235 | if (_Jv_PthreadCheckMonitor (mu)) |
236 | return _JV_NOT_OWNER; | |
237 | ||
238 | _Jv_Thread_t *target; | |
239 | _Jv_Thread_t *prev = NULL; | |
240 | ||
241 | for (target = cv->first; target != NULL; target = target->next) | |
ee9dd372 | 242 | { |
b834f1fa BM |
243 | pthread_mutex_lock (&target->wait_mutex); |
244 | pthread_cond_signal (&target->wait_cond); | |
245 | pthread_mutex_unlock (&target->wait_mutex); | |
246 | ||
247 | if (prev != NULL) | |
248 | prev->next = NULL; | |
249 | prev = target; | |
ee9dd372 | 250 | } |
b834f1fa BM |
251 | if (prev != NULL) |
252 | prev->next = NULL; | |
253 | ||
254 | cv->first = NULL; | |
255 | ||
ee9dd372 TT |
256 | return 0; |
257 | } | |
258 | ||
b834f1fa BM |
259 | void |
260 | _Jv_ThreadInterrupt (_Jv_Thread_t *data) | |
ee9dd372 | 261 | { |
b834f1fa | 262 | pthread_mutex_lock (&data->wait_mutex); |
ee9dd372 | 263 | |
b834f1fa BM |
264 | // Set the thread's interrupted flag *after* aquiring its wait_mutex. This |
265 | // ensures that there are no races with the interrupt flag being set after | |
266 | // the waiting thread checks it and before pthread_cond_wait is entered. | |
267 | data->thread_obj->interrupt_flag = true; | |
268 | ||
269 | // Interrupt blocking system calls using a signal. | |
270 | // pthread_kill (data->thread, INTR); | |
271 | ||
272 | pthread_cond_signal (&data->wait_cond); | |
273 | ||
274 | pthread_mutex_unlock (&data->wait_mutex); | |
275 | } | |
ee9dd372 TT |
276 | |
277 | static void | |
278 | handle_intr (int) | |
279 | { | |
280 | // Do nothing. | |
281 | } | |
282 | ||
283 | void | |
284 | _Jv_InitThreads (void) | |
285 | { | |
286 | pthread_key_create (&_Jv_ThreadKey, NULL); | |
fd59e3a0 | 287 | pthread_key_create (&_Jv_ThreadDataKey, NULL); |
ee9dd372 TT |
288 | pthread_mutex_init (&daemon_mutex, NULL); |
289 | pthread_cond_init (&daemon_cond, 0); | |
290 | non_daemon_count = 0; | |
291 | ||
292 | // Arrange for the interrupt signal to interrupt system calls. | |
293 | struct sigaction act; | |
294 | act.sa_handler = handle_intr; | |
295 | sigemptyset (&act.sa_mask); | |
296 | act.sa_flags = 0; | |
297 | sigaction (INTR, &act, NULL); | |
ee9dd372 TT |
298 | } |
299 | ||
e301621d BM |
300 | _Jv_Thread_t * |
301 | _Jv_ThreadInitData (java::lang::Thread *obj) | |
ee9dd372 | 302 | { |
e301621d BM |
303 | _Jv_Thread_t *data = new _Jv_Thread_t; |
304 | data->flags = 0; | |
305 | data->thread_obj = obj; | |
b834f1fa | 306 | |
e301621d BM |
307 | pthread_mutex_init (&data->wait_mutex, NULL); |
308 | pthread_cond_init (&data->wait_cond, NULL); | |
ee9dd372 | 309 | |
e301621d BM |
310 | return data; |
311 | } | |
ee9dd372 | 312 | |
e301621d BM |
313 | void |
314 | _Jv_ThreadDestroyData (_Jv_Thread_t *data) | |
315 | { | |
316 | pthread_mutex_destroy (&data->wait_mutex); | |
317 | pthread_cond_destroy (&data->wait_cond); | |
318 | delete data; | |
ee9dd372 TT |
319 | } |
320 | ||
321 | void | |
322 | _Jv_ThreadSetPriority (_Jv_Thread_t *data, jint prio) | |
323 | { | |
324 | if (data->flags & FLAG_START) | |
325 | { | |
326 | struct sched_param param; | |
327 | ||
328 | param.sched_priority = prio; | |
329 | pthread_setschedparam (data->thread, SCHED_RR, ¶m); | |
330 | } | |
331 | } | |
332 | ||
ee9dd372 TT |
333 | // This function is called when a thread is started. We don't arrange |
334 | // to call the `run' method directly, because this function must | |
335 | // return a value. | |
336 | static void * | |
337 | really_start (void *x) | |
338 | { | |
339 | struct starter *info = (struct starter *) x; | |
340 | ||
b834f1fa | 341 | pthread_setspecific (_Jv_ThreadKey, info->data->thread_obj); |
fd59e3a0 | 342 | pthread_setspecific (_Jv_ThreadDataKey, info->data); |
ee9dd372 | 343 | |
b834f1fa BM |
344 | // glibc 2.1.3 doesn't set the value of `thread' until after start_routine |
345 | // is called. Since it may need to be accessed from the new thread, work | |
346 | // around the potential race here by explicitly setting it again. | |
347 | info->data->thread = pthread_self (); | |
348 | ||
349 | info->method (info->data->thread_obj); | |
350 | ||
ee9dd372 TT |
351 | if (! (info->data->flags & FLAG_DAEMON)) |
352 | { | |
353 | pthread_mutex_lock (&daemon_mutex); | |
354 | --non_daemon_count; | |
355 | if (! non_daemon_count) | |
356 | pthread_cond_signal (&daemon_cond); | |
357 | pthread_mutex_unlock (&daemon_mutex); | |
358 | } | |
b834f1fa | 359 | |
ee9dd372 TT |
360 | return NULL; |
361 | } | |
362 | ||
363 | void | |
364 | _Jv_ThreadStart (java::lang::Thread *thread, _Jv_Thread_t *data, | |
365 | _Jv_ThreadStartFunc *meth) | |
366 | { | |
367 | struct sched_param param; | |
368 | pthread_attr_t attr; | |
369 | struct starter *info; | |
370 | ||
371 | if (data->flags & FLAG_START) | |
372 | return; | |
373 | data->flags |= FLAG_START; | |
374 | ||
375 | param.sched_priority = thread->getPriority(); | |
376 | ||
377 | pthread_attr_init (&attr); | |
378 | pthread_attr_setschedparam (&attr, ¶m); | |
e301621d | 379 | pthread_attr_setdetachstate (&attr, PTHREAD_CREATE_DETACHED); |
ee9dd372 TT |
380 | |
381 | // FIXME: handle marking the info object for GC. | |
382 | info = (struct starter *) _Jv_AllocBytes (sizeof (struct starter)); | |
383 | info->method = meth; | |
ee9dd372 TT |
384 | info->data = data; |
385 | ||
386 | if (! thread->isDaemon()) | |
387 | { | |
388 | pthread_mutex_lock (&daemon_mutex); | |
389 | ++non_daemon_count; | |
390 | pthread_mutex_unlock (&daemon_mutex); | |
391 | } | |
392 | else | |
393 | data->flags |= FLAG_DAEMON; | |
43cbc943 BM |
394 | int r = pthread_create (&data->thread, &attr, really_start, (void *) info); |
395 | ||
ee9dd372 | 396 | pthread_attr_destroy (&attr); |
43cbc943 BM |
397 | |
398 | if (r) | |
399 | { | |
400 | const char* msg = "Cannot create additional threads"; | |
401 | JvThrow (new java::lang::OutOfMemoryError (JvNewStringUTF (msg))); | |
402 | } | |
ee9dd372 TT |
403 | } |
404 | ||
405 | void | |
406 | _Jv_ThreadWait (void) | |
407 | { | |
ee9dd372 TT |
408 | pthread_mutex_lock (&daemon_mutex); |
409 | if (non_daemon_count) | |
410 | pthread_cond_wait (&daemon_cond, &daemon_mutex); | |
411 | pthread_mutex_unlock (&daemon_mutex); | |
412 | } |