2 * Copyright (c) 2005 David Xu <davidxu@freebsd.org>
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice unmodified, this list of conditions, and the following
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.
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.
28 #include "namespace.h"
29 #include <machine/tls.h>
34 #include "un-namespace.h"
36 #include "thr_private.h"
38 #ifdef _PTHREADS_DEBUGGING
44 #define cpu_ccfence() __asm __volatile("" : : : "memory")
46 umtx_t _cond_static_lock
;
48 #ifdef _PTHREADS_DEBUGGING
52 cond_log(const char *ctl
, ...)
59 len
= vsnprintf(buf
, sizeof(buf
), ctl
, va
);
68 cond_log(const char *ctl __unused
, ...)
77 int __pthread_cond_wait(pthread_cond_t
*cond
, pthread_mutex_t
*mutex
);
78 int __pthread_cond_timedwait(pthread_cond_t
*cond
, pthread_mutex_t
*mutex
,
79 const struct timespec
*abstime
);
80 static int cond_wait_common(pthread_cond_t
*cond
, pthread_mutex_t
*mutex
,
81 const struct timespec
*abstime
, int cancel
);
82 static int cond_signal_common(pthread_cond_t
*cond
, int broadcast
);
85 cond_init(pthread_cond_t
*cond
, const pthread_condattr_t
*cond_attr
)
90 pcond
= __malloc(sizeof(struct __pthread_cond_s
));
95 * Initialise the condition variable structure:
97 _thr_umtx_init(&pcond
->c_lock
);
98 if (cond_attr
== NULL
|| *cond_attr
== NULL
) {
100 pcond
->c_clockid
= CLOCK_REALTIME
;
102 pcond
->c_pshared
= (*cond_attr
)->c_pshared
;
103 pcond
->c_clockid
= (*cond_attr
)->c_clockid
;
105 TAILQ_INIT(&pcond
->c_waitlist
);
108 /* Return the completion status: */
114 _cond_reinit(pthread_cond_t cond
)
117 _thr_umtx_init(&cond
->c_lock
);
121 cond
->c_clockid
= CLOCK_REALTIME
;
123 TAILQ_INIT(&cond
->c_waitlist
);
129 init_static(pthread_t thread
, pthread_cond_t
*cond
)
133 THR_LOCK_ACQUIRE(thread
, &_cond_static_lock
);
136 ret
= cond_init(cond
, NULL
);
140 THR_LOCK_RELEASE(thread
, &_cond_static_lock
);
146 _pthread_cond_init(pthread_cond_t
* __restrict cond
,
147 const pthread_condattr_t
* __restrict cond_attr
)
150 return cond_init(cond
, cond_attr
);
154 _pthread_cond_destroy(pthread_cond_t
*cond
)
157 pthread_t curthread
= tls_get_curthread();
162 } else if (*cond
== NULL
) {
165 /* Lock the condition variable structure: */
166 THR_LOCK_ACQUIRE(curthread
, &(*cond
)->c_lock
);
167 if (TAILQ_FIRST(&(*cond
)->c_waitlist
)) {
168 THR_LOCK_RELEASE(curthread
, &(*cond
)->c_lock
);
173 * NULL the caller's pointer now that the condition
174 * variable has been destroyed:
179 /* Unlock the condition variable structure: */
180 THR_LOCK_RELEASE(curthread
, &cv
->c_lock
);
182 /* Free the cond lock structure: */
185 * Free the memory allocated for the condition
186 * variable structure:
191 /* Return the completion status: */
195 struct cond_cancel_info
{
196 TAILQ_ENTRY(cond_cancel_info
) entry
;
197 pthread_mutex_t
*mutex
;
198 pthread_cond_t
*cond
;
204 cond_cancel_handler(void *arg
)
206 pthread_t curthread
= tls_get_curthread();
207 struct cond_cancel_info
*info
= (struct cond_cancel_info
*)arg
;
211 THR_LOCK_ACQUIRE(curthread
, &cv
->c_lock
);
212 cond_log("cond_cancel %p\n", cv
);
216 cond_log("cond_cancel %p: info %p\n", cv
, info
);
217 TAILQ_REMOVE(&cv
->c_waitlist
, info
, entry
);
218 _thr_umtx_wake(&info
->queued
, 0);
220 THR_LOCK_RELEASE(curthread
, &cv
->c_lock
);
222 /* _mutex_cv_lock(info->mutex, info->count); */
226 * Wait for pthread_cond_t to be signaled.
228 * NOTE: EINTR is ignored and may not be returned by this function.
231 cond_wait_common(pthread_cond_t
*cond
, pthread_mutex_t
*mutex
,
232 const struct timespec
*abstime
, int cancel
)
234 pthread_t curthread
= tls_get_curthread();
235 struct timespec ts
, ts2
, *tsp
;
236 struct cond_cancel_info info
;
242 * If the condition variable is statically initialized,
243 * perform the dynamic initialization:
245 cond_log("cond_wait_common %p on mutex %p info %p\n",
246 *cond
, *mutex
, &info
);
247 if (__predict_false(*cond
== NULL
&&
248 (ret
= init_static(curthread
, cond
)) != 0)) {
249 cond_log("cond_wait_common %p (failedA %d)\n", *cond
, ret
);
254 THR_LOCK_ACQUIRE(curthread
, &cv
->c_lock
);
255 ret
= _mutex_cv_unlock(mutex
, &info
.count
);
257 cond_log("cond_wait_common %p (failedB %d)\n", cv
, ret
);
258 THR_LOCK_RELEASE(curthread
, &cv
->c_lock
);
266 TAILQ_INSERT_TAIL(&cv
->c_waitlist
, &info
, entry
);
269 * loop if we have never been told to wake up
272 while (info
.queued
) {
273 THR_LOCK_RELEASE(curthread
, &cv
->c_lock
);
275 if (abstime
!= NULL
) {
276 clock_gettime(cv
->c_clockid
, &ts
);
277 timespecsub(abstime
, &ts
, &ts2
);
284 THR_CLEANUP_PUSH(curthread
, cond_cancel_handler
, &info
);
285 oldcancel
= _thr_cancel_enter(curthread
);
286 ret
= _thr_umtx_wait(&info
.queued
, 1, tsp
,
288 _thr_cancel_leave(curthread
, oldcancel
);
289 THR_CLEANUP_POP(curthread
, 0);
291 ret
= _thr_umtx_wait(&info
.queued
, 1, tsp
,
296 * Ignore EINTR. Make sure ret is 0 if not ETIMEDOUT.
298 THR_LOCK_ACQUIRE(curthread
, &cv
->c_lock
);
299 if (abstime
!= NULL
&& ret
== ETIMEDOUT
)
306 TAILQ_REMOVE(&cv
->c_waitlist
, &info
, entry
);
311 THR_LOCK_RELEASE(curthread
, &cv
->c_lock
);
313 cond_log("cond_wait_common %p (doneA)\n", cv
);
314 _mutex_cv_lock(mutex
, info
.count
);
317 cond_log("cond_wait_common %p (failed %d)\n", cv
, ret
);
319 cond_log("cond_wait_common %p (doneB)\n", cv
);
325 _pthread_cond_wait(pthread_cond_t
*cond
, pthread_mutex_t
*mutex
)
327 return (cond_wait_common(cond
, mutex
, NULL
, 0));
331 __pthread_cond_wait(pthread_cond_t
* __restrict cond
,
332 pthread_mutex_t
* __restrict mutex
)
334 return (cond_wait_common(cond
, mutex
, NULL
, 1));
338 _pthread_cond_timedwait(pthread_cond_t
* __restrict cond
,
339 pthread_mutex_t
* __restrict mutex
,
340 const struct timespec
* __restrict abstime
)
342 if (abstime
== NULL
|| abstime
->tv_sec
< 0 || abstime
->tv_nsec
< 0 ||
343 abstime
->tv_nsec
>= 1000000000)
346 return (cond_wait_common(cond
, mutex
, abstime
, 0));
350 __pthread_cond_timedwait(pthread_cond_t
*cond
, pthread_mutex_t
*mutex
,
351 const struct timespec
*abstime
)
353 if (abstime
== NULL
|| abstime
->tv_sec
< 0 || abstime
->tv_nsec
< 0 ||
354 abstime
->tv_nsec
>= 1000000000)
357 return (cond_wait_common(cond
, mutex
, abstime
, 1));
361 cond_signal_common(pthread_cond_t
*cond
, int broadcast
)
363 pthread_t curthread
= tls_get_curthread();
364 struct cond_cancel_info
*info
;
368 cond_log("cond_signal_common %p broad=%d\n", *cond
, broadcast
);
371 * If the condition variable is statically initialized, perform dynamic
374 if (__predict_false(*cond
== NULL
&&
375 (ret
= init_static(curthread
, cond
)) != 0)) {
376 cond_log("cond_signal_common %p (failedA %d)\n", *cond
, ret
);
381 /* Lock the condition variable structure. */
382 THR_LOCK_ACQUIRE(curthread
, &cv
->c_lock
);
383 while ((info
= TAILQ_FIRST(&cv
->c_waitlist
)) != NULL
) {
385 TAILQ_REMOVE(&cv
->c_waitlist
, info
, entry
);
386 cond_log("cond_signal_common %p: wakeup %p\n", *cond
, info
);
387 _thr_umtx_wake(&info
->queued
, 0);
391 THR_LOCK_RELEASE(curthread
, &cv
->c_lock
);
394 cond_log("cond_signal_common %p (failedB %d)\n", *cond
, ret
);
396 cond_log("cond_signal_common %p (done)\n", *cond
);
402 _pthread_cond_signal(pthread_cond_t
* cond
)
404 return (cond_signal_common(cond
, 0));
408 _pthread_cond_broadcast(pthread_cond_t
* cond
)
410 return (cond_signal_common(cond
, 1));
414 * Double underscore versions are cancellation points. Single underscore
415 * versions are not and are provided for libc internal usage (which
416 * shouldn't introduce cancellation points).
418 __strong_reference(__pthread_cond_wait
, pthread_cond_wait
);
419 __strong_reference(__pthread_cond_timedwait
, pthread_cond_timedwait
);
421 __strong_reference(_pthread_cond_init
, pthread_cond_init
);
422 __strong_reference(_pthread_cond_destroy
, pthread_cond_destroy
);
423 __strong_reference(_pthread_cond_signal
, pthread_cond_signal
);
424 __strong_reference(_pthread_cond_broadcast
, pthread_cond_broadcast
);