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

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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 * $FreeBSD: head/lib/librt/sigev_thread.c 156383 2006-03-07 08:28:07Z davidxu $
27 *
28 */
29
30#include <sys/types.h>
31#include <machine/atomic.h>
32
33#include "namespace.h"
34#include <err.h>
35#include <errno.h>
36#include <ucontext.h>
37#include <sys/thr.h>
38#include <stdio.h>
39#include <stdlib.h>
40#include <string.h>
41#include <signal.h>
42#include <pthread.h>
43#include "un-namespace.h"
44
45#include "sigev_thread.h"
46
47LIST_HEAD(sigev_list_head, sigev_node);
48#define HASH_QUEUES 17
49#define HASH(t, id) ((((id) << 3) + (t)) % HASH_QUEUES)
50
51static struct sigev_list_head sigev_hash[HASH_QUEUES];
52static struct sigev_list_head sigev_all;
53static LIST_HEAD(,sigev_thread) sigev_threads;
54static int sigev_generation;
55static pthread_mutex_t *sigev_list_mtx;
56static pthread_once_t sigev_once = PTHREAD_ONCE_INIT;
57static pthread_once_t sigev_once_default = PTHREAD_ONCE_INIT;
58static struct sigev_thread *sigev_default_thread;
59static pthread_attr_t sigev_default_attr;
60static int atfork_registered;
61
62static void __sigev_fork_prepare(void);
63static void __sigev_fork_parent(void);
64static void __sigev_fork_child(void);
65static struct sigev_thread *sigev_thread_create(int);
66static void *sigev_service_loop(void *);
67static void *worker_routine(void *);
68static void worker_cleanup(void *);
69
70#pragma weak pthread_create
71
72static void
73attrcopy(pthread_attr_t *src, pthread_attr_t *dst)
74{
75 struct sched_param sched;
76 void *a;
77 size_t u;
78 int v;
79
80 _pthread_attr_getschedpolicy(src, &v);
81 _pthread_attr_setschedpolicy(dst, v);
82
83 _pthread_attr_getinheritsched(src, &v);
84 _pthread_attr_setinheritsched(dst, v);
85
86 _pthread_attr_getschedparam(src, &sched);
87 _pthread_attr_setschedparam(dst, &sched);
88
89 _pthread_attr_getscope(src, &v);
90 _pthread_attr_setscope(dst, v);
91
92 _pthread_attr_getstacksize(src, &u);
93 _pthread_attr_setstacksize(dst, u);
94
95 _pthread_attr_getstackaddr(src, &a);
96 _pthread_attr_setstackaddr(src, a);
97
98 _pthread_attr_getguardsize(src, &u);
99 _pthread_attr_setguardsize(dst, u);
100}
101
102static __inline int
103have_threads(void)
104{
105 return (&pthread_create != NULL);
106}
107
108void
109__sigev_thread_init(void)
110{
111 static int inited = 0;
112 pthread_mutexattr_t mattr;
113 int i;
114
115 _pthread_mutexattr_init(&mattr);
116 _pthread_mutexattr_settype(&mattr, PTHREAD_MUTEX_NORMAL);
117 sigev_list_mtx = malloc(sizeof(pthread_mutex_t));
118 _pthread_mutex_init(sigev_list_mtx, &mattr);
119 _pthread_mutexattr_destroy(&mattr);
120
121 for (i = 0; i < HASH_QUEUES; ++i)
122 LIST_INIT(&sigev_hash[i]);
123 LIST_INIT(&sigev_all);
124 LIST_INIT(&sigev_threads);
125 sigev_default_thread = NULL;
126 if (atfork_registered == 0) {
127 _pthread_atfork(
128 __sigev_fork_prepare,
129 __sigev_fork_parent,
130 __sigev_fork_child);
131 atfork_registered = 1;
132 }
133 if (!inited) {
134 _pthread_attr_init(&sigev_default_attr);
135 _pthread_attr_setscope(&sigev_default_attr,
136 PTHREAD_SCOPE_SYSTEM);
137 _pthread_attr_setdetachstate(&sigev_default_attr,
138 PTHREAD_CREATE_DETACHED);
139 inited = 1;
140 }
141 sigev_default_thread = sigev_thread_create(0);
142}
143
144int
145__sigev_check_init(void)
146{
147 if (!have_threads())
148 return (-1);
149

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169 * check if the handlers were already registered in
170 * pthread_atfork().
171 */
172 atfork_registered = 1;
173 memcpy(&sigev_once, &sigev_once_default, sizeof(sigev_once));
174 __sigev_thread_init();
175}
176
177void
178__sigev_list_lock(void)
179{
180 _pthread_mutex_lock(sigev_list_mtx);
181}
182
183void
184__sigev_list_unlock(void)
185{
186 _pthread_mutex_unlock(sigev_list_mtx);
187}
188
189struct sigev_node *
190__sigev_alloc(int type, const struct sigevent *evp, struct sigev_node *prev,
191 int usedefault)
192{
193 struct sigev_node *sn;
194
195 sn = calloc(1, sizeof(*sn));
196 if (sn != NULL) {
197 sn->sn_value = evp->sigev_value;
198 sn->sn_func = evp->sigev_notify_function;
199 sn->sn_gen = atomic_fetchadd_int(&sigev_generation, 1);
200 sn->sn_type = type;
201 _pthread_attr_init(&sn->sn_attr);
202 _pthread_attr_setdetachstate(&sn->sn_attr, PTHREAD_CREATE_DETACHED);
203 if (evp->sigev_notify_attributes)
204 attrcopy(evp->sigev_notify_attributes, &sn->sn_attr);
205 if (prev) {
206 __sigev_list_lock();
207 prev->sn_tn->tn_refcount++;
208 __sigev_list_unlock();
209 sn->sn_tn = prev->sn_tn;
210 } else {
211 sn->sn_tn = sigev_thread_create(usedefault);
212 if (sn->sn_tn == NULL) {
213 _pthread_attr_destroy(&sn->sn_attr);
214 free(sn);
215 sn = NULL;
216 }
217 }
218 }
219 return (sn);
220}
221
222void
223__sigev_get_sigevent(struct sigev_node *sn, struct sigevent *newevp,
224 sigev_id_t id)
225{
226 /*
227 * Build a new sigevent, and tell kernel to deliver SIGSERVICE
228 * signal to the new thread.
229 */
230 newevp->sigev_notify = SIGEV_THREAD_ID;
231 newevp->sigev_signo = SIGSERVICE;
232 newevp->sigev_notify_thread_id = (lwpid_t)sn->sn_tn->tn_lwpid;
233 newevp->sigev_value.sival_ptr = (void *)id;
234}
235
236void
237__sigev_free(struct sigev_node *sn)
238{
239 _pthread_attr_destroy(&sn->sn_attr);
240 free(sn);
241}
242
243struct sigev_node *
244__sigev_find(int type, sigev_id_t id)
245{
246 struct sigev_node *sn;
247 int chain = HASH(type, id);

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254}
255
256int
257__sigev_register(struct sigev_node *sn)
258{
259 int chain = HASH(sn->sn_type, sn->sn_id);
260
261 LIST_INSERT_HEAD(&sigev_hash[chain], sn, sn_link);
262 return (0);
263}
264
265int
266__sigev_delete(int type, sigev_id_t id)
267{
268 struct sigev_node *sn;
269
270 sn = __sigev_find(type, id);
271 if (sn != NULL)
272 return (__sigev_delete_node(sn));
273 return (0);
274}
275
276int
277__sigev_delete_node(struct sigev_node *sn)
278{
279 LIST_REMOVE(sn, sn_link);
280
281 if (--sn->sn_tn->tn_refcount == 0)
282 _pthread_kill(sn->sn_tn->tn_thread, SIGSERVICE);
283 if (sn->sn_flags & SNF_WORKING)
284 sn->sn_flags |= SNF_REMOVED;
285 else
286 __sigev_free(sn);
287 return (0);
288}
289
290static sigev_id_t
291sigev_get_id(siginfo_t *si)
292{
293 switch(si->si_code) {
294 case SI_TIMER:
295 return (si->si_timerid);
296 case SI_MESGQ:
297 return (si->si_mqd);
298 case SI_ASYNCIO:
299 return (sigev_id_t)si->si_value.sival_ptr;
300 }
301 return (-1);
302}
303
304static struct sigev_thread *
305sigev_thread_create(int usedefault)
306{
307 struct sigev_thread *tn;
308 sigset_t set;
309 int ret;
310
311 if (usedefault && sigev_default_thread) {
312 __sigev_list_lock();
313 sigev_default_thread->tn_refcount++;
314 __sigev_list_unlock();
315 return (sigev_default_thread);
316 }
317
318 tn = malloc(sizeof(*tn));
319 tn->tn_cur = NULL;
320 tn->tn_lwpid = -1;
321 tn->tn_refcount = 1;
322 _pthread_cond_init(&tn->tn_cv, NULL);
323
324 /* for debug */
325 __sigev_list_lock();
326 LIST_INSERT_HEAD(&sigev_threads, tn, tn_link);
327 __sigev_list_unlock();
328
329 sigemptyset(&set);
330 sigaddset(&set, SIGSERVICE);
331
332 _sigprocmask(SIG_BLOCK, &set, NULL);
333 ret = pthread_create(&tn->tn_thread, &sigev_default_attr,
334 sigev_service_loop, tn);
335 _sigprocmask(SIG_UNBLOCK, &set, NULL);
336
337 if (ret != 0) {
338 __sigev_list_lock();
339 LIST_REMOVE(tn, tn_link);
340 __sigev_list_unlock();
341 free(tn);
342 tn = NULL;
343 } else {
344 /* wait the thread to get its lwpid */
345
346 __sigev_list_lock();
347 while (tn->tn_lwpid == -1)
348 _pthread_cond_wait(&tn->tn_cv, sigev_list_mtx);
349 __sigev_list_unlock();
350 }
351 return (tn);
352}
353
354/*
355 * The thread receives notification from kernel and creates
356 * a thread to call user callback function.
357 */
358static void *
359sigev_service_loop(void *arg)
360{
361 static int failure;
362
363 siginfo_t si;
364 sigset_t set;
365 struct sigev_thread *tn;
366 struct sigev_node *sn;
367 sigev_id_t id;
368 pthread_t td;
369 int ret;
370
371 tn = arg;
372 thr_self(&tn->tn_lwpid);
373 __sigev_list_lock();
374 _pthread_cond_broadcast(&tn->tn_cv);
375 __sigev_list_unlock();
376
377 /*
378 * Service thread should not be killed by callback, if user
379 * attempts to do so, the thread will be restarted.
380 */
381 sigemptyset(&set);
382 sigaddset(&set, SIGSERVICE);
383 for (;;) {
384 ret = sigwaitinfo(&set, &si);
385
386 __sigev_list_lock();
387 if (tn->tn_refcount == 0) {
388 LIST_REMOVE(tn, tn_link);
389 __sigev_list_unlock();
390 free(tn);
391 break;
392 }
393
394 if (ret == -1) {
395 __sigev_list_unlock();
396 continue;
397 }
398
399 id = sigev_get_id(&si);
400 sn = __sigev_find(si.si_code, id);
401 if (sn == NULL) {
402 __sigev_list_unlock();
403 continue;
404 }
405
406 sn->sn_info = si;
407 if (sn->sn_flags & SNF_SYNC)
408 tn->tn_cur = sn;
409 else
410 tn->tn_cur = NULL;
411 sn->sn_flags |= SNF_WORKING;
412 __sigev_list_unlock();
413
414 ret = pthread_create(&td, &sn->sn_attr, worker_routine, sn);
415 if (ret != 0) {
416 if (failure++ < 5)
417 warnc(ret, "%s:%s failed to create thread.\n",
418 __FILE__, __func__);
419
420 __sigev_list_lock();
421 sn->sn_flags &= ~SNF_WORKING;
422 if (sn->sn_flags & SNF_REMOVED)
423 __sigev_free(sn);
424 __sigev_list_unlock();
425 } else if (tn->tn_cur) {
426 __sigev_list_lock();
427 while (tn->tn_cur)
428 _pthread_cond_wait(&tn->tn_cv, sigev_list_mtx);
429 __sigev_list_unlock();
430 }
431 }
432 return (0);
433}
434
435/*
436 * newly created worker thread to call user callback function.
437 */
438static void *
439worker_routine(void *arg)
440{
441 struct sigev_node *sn = arg;
442
443 _pthread_cleanup_push(worker_cleanup, sn);
444 sn->sn_dispatch(sn);
445 _pthread_cleanup_pop(1);
446
447 return (0);
448}
449
450/* clean up a notification after dispatch. */
451static void
452worker_cleanup(void *arg)
453{
454 struct sigev_node *sn = arg;
455
456 __sigev_list_lock();
457 if (sn->sn_flags & SNF_SYNC) {
458 sn->sn_tn->tn_cur = NULL;
459 _pthread_cond_broadcast(&sn->sn_tn->tn_cv);
460 }
461 if (sn->sn_flags & SNF_REMOVED)
462 __sigev_free(sn);
463 else
464 sn->sn_flags &= ~SNF_WORKING;
465 __sigev_list_unlock();
466}