xref: /freebsd/lib/libthr/thread/thr_init.c (revision 5dae51da3da0cc94d17bd67b308fad304ebec7e0)
1 /*
2  * Copyright (c) 2003 Daniel M. Eischen <deischen@freebsd.org>
3  * Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>
4  * All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following 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  * 3. All advertising materials mentioning features or use of this software
15  *    must display the following acknowledgement:
16  *	This product includes software developed by John Birrell.
17  * 4. Neither the name of the author nor the names of any co-contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #include <sys/cdefs.h>
35 __FBSDID("$FreeBSD$");
36 
37 #include "namespace.h"
38 #include <sys/types.h>
39 #include <sys/signalvar.h>
40 #include <sys/ioctl.h>
41 #include <sys/link_elf.h>
42 #include <sys/resource.h>
43 #include <sys/sysctl.h>
44 #include <sys/ttycom.h>
45 #include <sys/mman.h>
46 #include <sys/rtprio.h>
47 #include <errno.h>
48 #include <fcntl.h>
49 #include <paths.h>
50 #include <pthread.h>
51 #include <pthread_np.h>
52 #include <signal.h>
53 #include <stdlib.h>
54 #include <string.h>
55 #include <time.h>
56 #include <unistd.h>
57 #include "un-namespace.h"
58 
59 #include "libc_private.h"
60 #include "thr_private.h"
61 
62 char		*_usrstack;
63 struct pthread	*_thr_initial;
64 int		_libthr_debug;
65 int		_thread_event_mask;
66 struct pthread	*_thread_last_event;
67 pthreadlist	_thread_list = TAILQ_HEAD_INITIALIZER(_thread_list);
68 pthreadlist 	_thread_gc_list = TAILQ_HEAD_INITIALIZER(_thread_gc_list);
69 int		_thread_active_threads = 1;
70 atfork_head	_thr_atfork_list = TAILQ_HEAD_INITIALIZER(_thr_atfork_list);
71 struct urwlock	_thr_atfork_lock = DEFAULT_URWLOCK;
72 
73 struct pthread_prio	_thr_priorities[3] = {
74 	{RTP_PRIO_MIN,  RTP_PRIO_MAX, 0}, /* FIFO */
75 	{0, 0, 63}, /* OTHER */
76 	{RTP_PRIO_MIN, RTP_PRIO_MAX, 0}  /* RR */
77 };
78 
79 struct pthread_attr _pthread_attr_default = {
80 	.sched_policy = SCHED_OTHER,
81 	.sched_inherit = PTHREAD_INHERIT_SCHED,
82 	.prio = 0,
83 	.suspend = THR_CREATE_RUNNING,
84 	.flags = PTHREAD_SCOPE_SYSTEM,
85 	.stackaddr_attr = NULL,
86 	.stacksize_attr = THR_STACK_DEFAULT,
87 	.guardsize_attr = 0,
88 	.cpusetsize = 0,
89 	.cpuset = NULL
90 };
91 
92 struct pthread_mutex_attr _pthread_mutexattr_default = {
93 	.m_type = PTHREAD_MUTEX_DEFAULT,
94 	.m_protocol = PTHREAD_PRIO_NONE,
95 	.m_ceiling = 0,
96 	.m_pshared = PTHREAD_PROCESS_PRIVATE,
97 	.m_robust = PTHREAD_MUTEX_STALLED,
98 };
99 
100 struct pthread_mutex_attr _pthread_mutexattr_adaptive_default = {
101 	.m_type = PTHREAD_MUTEX_ADAPTIVE_NP,
102 	.m_protocol = PTHREAD_PRIO_NONE,
103 	.m_ceiling = 0,
104 	.m_pshared = PTHREAD_PROCESS_PRIVATE,
105 	.m_robust = PTHREAD_MUTEX_STALLED,
106 };
107 
108 /* Default condition variable attributes: */
109 struct pthread_cond_attr _pthread_condattr_default = {
110 	.c_pshared = PTHREAD_PROCESS_PRIVATE,
111 	.c_clockid = CLOCK_REALTIME
112 };
113 
114 int		_thr_is_smp = 0;
115 size_t		_thr_guard_default;
116 size_t		_thr_stack_default = THR_STACK_DEFAULT;
117 size_t		_thr_stack_initial = THR_STACK_INITIAL;
118 int		_thr_page_size;
119 int		_thr_spinloops;
120 int		_thr_yieldloops;
121 int		_thr_queuefifo = 4;
122 int		_gc_count;
123 struct umutex	_mutex_static_lock = DEFAULT_UMUTEX;
124 struct umutex	_cond_static_lock = DEFAULT_UMUTEX;
125 struct umutex	_rwlock_static_lock = DEFAULT_UMUTEX;
126 struct umutex	_keytable_lock = DEFAULT_UMUTEX;
127 struct urwlock	_thr_list_lock = DEFAULT_URWLOCK;
128 struct umutex	_thr_event_lock = DEFAULT_UMUTEX;
129 struct umutex	_suspend_all_lock = DEFAULT_UMUTEX;
130 struct pthread	*_single_thread;
131 int		_suspend_all_cycle;
132 int		_suspend_all_waiters;
133 
134 int	__pthread_cond_wait(pthread_cond_t *, pthread_mutex_t *);
135 int	__pthread_mutex_lock(pthread_mutex_t *);
136 int	__pthread_mutex_trylock(pthread_mutex_t *);
137 void	_thread_init_hack(void) __attribute__ ((constructor));
138 
139 static void init_private(void);
140 static void init_main_thread(struct pthread *thread);
141 
142 /*
143  * All weak references used within libc should be in this table.
144  * This is so that static libraries will work.
145  */
146 
147 STATIC_LIB_REQUIRE(_fork);
148 STATIC_LIB_REQUIRE(_pthread_getspecific);
149 STATIC_LIB_REQUIRE(_pthread_key_create);
150 STATIC_LIB_REQUIRE(_pthread_key_delete);
151 STATIC_LIB_REQUIRE(_pthread_mutex_destroy);
152 STATIC_LIB_REQUIRE(_pthread_mutex_init);
153 STATIC_LIB_REQUIRE(_pthread_mutex_lock);
154 STATIC_LIB_REQUIRE(_pthread_mutex_trylock);
155 STATIC_LIB_REQUIRE(_pthread_mutex_unlock);
156 STATIC_LIB_REQUIRE(_pthread_mutexattr_init);
157 STATIC_LIB_REQUIRE(_pthread_mutexattr_destroy);
158 STATIC_LIB_REQUIRE(_pthread_mutexattr_settype);
159 STATIC_LIB_REQUIRE(_pthread_once);
160 STATIC_LIB_REQUIRE(_pthread_setspecific);
161 STATIC_LIB_REQUIRE(_raise);
162 STATIC_LIB_REQUIRE(_sem_destroy);
163 STATIC_LIB_REQUIRE(_sem_getvalue);
164 STATIC_LIB_REQUIRE(_sem_init);
165 STATIC_LIB_REQUIRE(_sem_post);
166 STATIC_LIB_REQUIRE(_sem_timedwait);
167 STATIC_LIB_REQUIRE(_sem_trywait);
168 STATIC_LIB_REQUIRE(_sem_wait);
169 STATIC_LIB_REQUIRE(_sigaction);
170 STATIC_LIB_REQUIRE(_sigprocmask);
171 STATIC_LIB_REQUIRE(_sigsuspend);
172 STATIC_LIB_REQUIRE(_sigtimedwait);
173 STATIC_LIB_REQUIRE(_sigwait);
174 STATIC_LIB_REQUIRE(_sigwaitinfo);
175 STATIC_LIB_REQUIRE(_spinlock);
176 STATIC_LIB_REQUIRE(_spinlock_debug);
177 STATIC_LIB_REQUIRE(_spinunlock);
178 STATIC_LIB_REQUIRE(_thread_init_hack);
179 
180 /*
181  * These are needed when linking statically.  All references within
182  * libgcc (and in the future libc) to these routines are weak, but
183  * if they are not (strongly) referenced by the application or other
184  * libraries, then the actual functions will not be loaded.
185  */
186 STATIC_LIB_REQUIRE(_pthread_once);
187 STATIC_LIB_REQUIRE(_pthread_key_create);
188 STATIC_LIB_REQUIRE(_pthread_key_delete);
189 STATIC_LIB_REQUIRE(_pthread_getspecific);
190 STATIC_LIB_REQUIRE(_pthread_setspecific);
191 STATIC_LIB_REQUIRE(_pthread_mutex_init);
192 STATIC_LIB_REQUIRE(_pthread_mutex_destroy);
193 STATIC_LIB_REQUIRE(_pthread_mutex_lock);
194 STATIC_LIB_REQUIRE(_pthread_mutex_trylock);
195 STATIC_LIB_REQUIRE(_pthread_mutex_unlock);
196 STATIC_LIB_REQUIRE(_pthread_create);
197 
198 /* Pull in all symbols required by libthread_db */
199 STATIC_LIB_REQUIRE(_thread_state_running);
200 
201 #define	DUAL_ENTRY(entry)	\
202 	(pthread_func_t)entry, (pthread_func_t)entry
203 
204 static pthread_func_t jmp_table[][2] = {
205 	{DUAL_ENTRY(_pthread_atfork)},	/* PJT_ATFORK */
206 	{DUAL_ENTRY(_pthread_attr_destroy)},	/* PJT_ATTR_DESTROY */
207 	{DUAL_ENTRY(_pthread_attr_getdetachstate)},	/* PJT_ATTR_GETDETACHSTATE */
208 	{DUAL_ENTRY(_pthread_attr_getguardsize)},	/* PJT_ATTR_GETGUARDSIZE */
209 	{DUAL_ENTRY(_pthread_attr_getinheritsched)},	/* PJT_ATTR_GETINHERITSCHED */
210 	{DUAL_ENTRY(_pthread_attr_getschedparam)},	/* PJT_ATTR_GETSCHEDPARAM */
211 	{DUAL_ENTRY(_pthread_attr_getschedpolicy)},	/* PJT_ATTR_GETSCHEDPOLICY */
212 	{DUAL_ENTRY(_pthread_attr_getscope)},	/* PJT_ATTR_GETSCOPE */
213 	{DUAL_ENTRY(_pthread_attr_getstackaddr)},	/* PJT_ATTR_GETSTACKADDR */
214 	{DUAL_ENTRY(_pthread_attr_getstacksize)},	/* PJT_ATTR_GETSTACKSIZE */
215 	{DUAL_ENTRY(_pthread_attr_init)},	/* PJT_ATTR_INIT */
216 	{DUAL_ENTRY(_pthread_attr_setdetachstate)},	/* PJT_ATTR_SETDETACHSTATE */
217 	{DUAL_ENTRY(_pthread_attr_setguardsize)},	/* PJT_ATTR_SETGUARDSIZE */
218 	{DUAL_ENTRY(_pthread_attr_setinheritsched)},	/* PJT_ATTR_SETINHERITSCHED */
219 	{DUAL_ENTRY(_pthread_attr_setschedparam)},	/* PJT_ATTR_SETSCHEDPARAM */
220 	{DUAL_ENTRY(_pthread_attr_setschedpolicy)},	/* PJT_ATTR_SETSCHEDPOLICY */
221 	{DUAL_ENTRY(_pthread_attr_setscope)},	/* PJT_ATTR_SETSCOPE */
222 	{DUAL_ENTRY(_pthread_attr_setstackaddr)},	/* PJT_ATTR_SETSTACKADDR */
223 	{DUAL_ENTRY(_pthread_attr_setstacksize)},	/* PJT_ATTR_SETSTACKSIZE */
224 	{DUAL_ENTRY(_pthread_cancel)},	/* PJT_CANCEL */
225 	{DUAL_ENTRY(_pthread_cleanup_pop)},	/* PJT_CLEANUP_POP */
226 	{DUAL_ENTRY(_pthread_cleanup_push)},	/* PJT_CLEANUP_PUSH */
227 	{DUAL_ENTRY(_pthread_cond_broadcast)},	/* PJT_COND_BROADCAST */
228 	{DUAL_ENTRY(_pthread_cond_destroy)},	/* PJT_COND_DESTROY */
229 	{DUAL_ENTRY(_pthread_cond_init)},	/* PJT_COND_INIT */
230 	{DUAL_ENTRY(_pthread_cond_signal)},	/* PJT_COND_SIGNAL */
231 	{DUAL_ENTRY(_pthread_cond_timedwait)},	/* PJT_COND_TIMEDWAIT */
232 	{(pthread_func_t)__pthread_cond_wait,
233 	 (pthread_func_t)_pthread_cond_wait},	/* PJT_COND_WAIT */
234 	{DUAL_ENTRY(_pthread_detach)},	/* PJT_DETACH */
235 	{DUAL_ENTRY(_pthread_equal)},	/* PJT_EQUAL */
236 	{DUAL_ENTRY(_pthread_exit)},	/* PJT_EXIT */
237 	{DUAL_ENTRY(_pthread_getspecific)},	/* PJT_GETSPECIFIC */
238 	{DUAL_ENTRY(_pthread_join)},	/* PJT_JOIN */
239 	{DUAL_ENTRY(_pthread_key_create)},	/* PJT_KEY_CREATE */
240 	{DUAL_ENTRY(_pthread_key_delete)},	/* PJT_KEY_DELETE*/
241 	{DUAL_ENTRY(_pthread_kill)},	/* PJT_KILL */
242 	{DUAL_ENTRY(_pthread_main_np)},		/* PJT_MAIN_NP */
243 	{DUAL_ENTRY(_pthread_mutexattr_destroy)}, /* PJT_MUTEXATTR_DESTROY */
244 	{DUAL_ENTRY(_pthread_mutexattr_init)},	/* PJT_MUTEXATTR_INIT */
245 	{DUAL_ENTRY(_pthread_mutexattr_settype)}, /* PJT_MUTEXATTR_SETTYPE */
246 	{DUAL_ENTRY(_pthread_mutex_destroy)},	/* PJT_MUTEX_DESTROY */
247 	{DUAL_ENTRY(_pthread_mutex_init)},	/* PJT_MUTEX_INIT */
248 	{(pthread_func_t)__pthread_mutex_lock,
249 	 (pthread_func_t)_pthread_mutex_lock},	/* PJT_MUTEX_LOCK */
250 	{(pthread_func_t)__pthread_mutex_trylock,
251 	 (pthread_func_t)_pthread_mutex_trylock},/* PJT_MUTEX_TRYLOCK */
252 	{DUAL_ENTRY(_pthread_mutex_unlock)},	/* PJT_MUTEX_UNLOCK */
253 	{DUAL_ENTRY(_pthread_once)},		/* PJT_ONCE */
254 	{DUAL_ENTRY(_pthread_rwlock_destroy)},	/* PJT_RWLOCK_DESTROY */
255 	{DUAL_ENTRY(_pthread_rwlock_init)},	/* PJT_RWLOCK_INIT */
256 	{DUAL_ENTRY(_pthread_rwlock_rdlock)},	/* PJT_RWLOCK_RDLOCK */
257 	{DUAL_ENTRY(_pthread_rwlock_tryrdlock)},/* PJT_RWLOCK_TRYRDLOCK */
258 	{DUAL_ENTRY(_pthread_rwlock_trywrlock)},/* PJT_RWLOCK_TRYWRLOCK */
259 	{DUAL_ENTRY(_pthread_rwlock_unlock)},	/* PJT_RWLOCK_UNLOCK */
260 	{DUAL_ENTRY(_pthread_rwlock_wrlock)},	/* PJT_RWLOCK_WRLOCK */
261 	{DUAL_ENTRY(_pthread_self)},		/* PJT_SELF */
262 	{DUAL_ENTRY(_pthread_setcancelstate)},	/* PJT_SETCANCELSTATE */
263 	{DUAL_ENTRY(_pthread_setcanceltype)},	/* PJT_SETCANCELTYPE */
264 	{DUAL_ENTRY(_pthread_setspecific)},	/* PJT_SETSPECIFIC */
265 	{DUAL_ENTRY(_pthread_sigmask)},		/* PJT_SIGMASK */
266 	{DUAL_ENTRY(_pthread_testcancel)},	/* PJT_TESTCANCEL */
267 	{DUAL_ENTRY(__pthread_cleanup_pop_imp)},/* PJT_CLEANUP_POP_IMP */
268 	{DUAL_ENTRY(__pthread_cleanup_push_imp)},/* PJT_CLEANUP_PUSH_IMP */
269 	{DUAL_ENTRY(_pthread_cancel_enter)},	/* PJT_CANCEL_ENTER */
270 	{DUAL_ENTRY(_pthread_cancel_leave)},	/* PJT_CANCEL_LEAVE */
271 	{DUAL_ENTRY(_pthread_mutex_consistent)},/* PJT_MUTEX_CONSISTENT */
272 	{DUAL_ENTRY(_pthread_mutexattr_getrobust)},/* PJT_MUTEXATTR_GETROBUST */
273 	{DUAL_ENTRY(_pthread_mutexattr_setrobust)},/* PJT_MUTEXATTR_SETROBUST */
274 };
275 
276 static int init_once = 0;
277 
278 /*
279  * For the shared version of the threads library, the above is sufficient.
280  * But for the archive version of the library, we need a little bit more.
281  * Namely, we must arrange for this particular module to be pulled in from
282  * the archive library at link time.  To accomplish that, we define and
283  * initialize a variable, "_thread_autoinit_dummy_decl".  This variable is
284  * referenced (as an extern) from libc/stdlib/exit.c. This will always
285  * create a need for this module, ensuring that it is present in the
286  * executable.
287  */
288 extern int _thread_autoinit_dummy_decl;
289 int _thread_autoinit_dummy_decl = 0;
290 
291 void
292 _thread_init_hack(void)
293 {
294 
295 	_libpthread_init(NULL);
296 }
297 
298 
299 /*
300  * Threaded process initialization.
301  *
302  * This is only called under two conditions:
303  *
304  *   1) Some thread routines have detected that the library hasn't yet
305  *      been initialized (_thr_initial == NULL && curthread == NULL), or
306  *
307  *   2) An explicit call to reinitialize after a fork (indicated
308  *      by curthread != NULL)
309  */
310 void
311 _libpthread_init(struct pthread *curthread)
312 {
313 	int first, dlopened;
314 
315 	/* Check if this function has already been called: */
316 	if (_thr_initial != NULL && curthread == NULL)
317 		/* Only initialize the threaded application once. */
318 		return;
319 
320 	/*
321 	 * Check the size of the jump table to make sure it is preset
322 	 * with the correct number of entries.
323 	 */
324 	if (sizeof(jmp_table) != sizeof(pthread_func_t) * PJT_MAX * 2)
325 		PANIC("Thread jump table not properly initialized");
326 	memcpy(__thr_jtable, jmp_table, sizeof(jmp_table));
327 	__thr_interpose_libc();
328 
329 	/* Initialize pthread private data. */
330 	init_private();
331 
332 	/* Set the initial thread. */
333 	if (curthread == NULL) {
334 		first = 1;
335 		/* Create and initialize the initial thread. */
336 		curthread = _thr_alloc(NULL);
337 		if (curthread == NULL)
338 			PANIC("Can't allocate initial thread");
339 		init_main_thread(curthread);
340 	} else {
341 		first = 0;
342 	}
343 
344 	/*
345 	 * Add the thread to the thread list queue.
346 	 */
347 	THR_LIST_ADD(curthread);
348 	_thread_active_threads = 1;
349 
350 	/* Setup the thread specific data */
351 	_tcb_set(curthread->tcb);
352 
353 	if (first) {
354 		_thr_initial = curthread;
355 		dlopened = _rtld_is_dlopened(&_thread_autoinit_dummy_decl) != 0;
356 		_thr_signal_init(dlopened);
357 		if (_thread_event_mask & TD_CREATE)
358 			_thr_report_creation(curthread, curthread);
359 		/*
360 		 * Always use our rtld lock implementation.
361 		 * It is faster because it postpones signal handlers
362 		 * instead of calling sigprocmask(2).
363 		 */
364 		_thr_rtld_init();
365 	}
366 }
367 
368 /*
369  * This function and pthread_create() do a lot of the same things.
370  * It'd be nice to consolidate the common stuff in one place.
371  */
372 static void
373 init_main_thread(struct pthread *thread)
374 {
375 	struct sched_param sched_param;
376 	int i;
377 
378 	/* Setup the thread attributes. */
379 	thr_self(&thread->tid);
380 	thread->attr = _pthread_attr_default;
381 	/*
382 	 * Set up the thread stack.
383 	 *
384 	 * Create a red zone below the main stack.  All other stacks
385 	 * are constrained to a maximum size by the parameters
386 	 * passed to mmap(), but this stack is only limited by
387 	 * resource limits, so this stack needs an explicitly mapped
388 	 * red zone to protect the thread stack that is just beyond.
389 	 */
390 	if (mmap(_usrstack - _thr_stack_initial -
391 	    _thr_guard_default, _thr_guard_default, 0, MAP_ANON,
392 	    -1, 0) == MAP_FAILED)
393 		PANIC("Cannot allocate red zone for initial thread");
394 
395 	/*
396 	 * Mark the stack as an application supplied stack so that it
397 	 * isn't deallocated.
398 	 *
399 	 * XXX - I'm not sure it would hurt anything to deallocate
400 	 *       the main thread stack because deallocation doesn't
401 	 *       actually free() it; it just puts it in the free
402 	 *       stack queue for later reuse.
403 	 */
404 	thread->attr.stackaddr_attr = _usrstack - _thr_stack_initial;
405 	thread->attr.stacksize_attr = _thr_stack_initial;
406 	thread->attr.guardsize_attr = _thr_guard_default;
407 	thread->attr.flags |= THR_STACK_USER;
408 
409 	/*
410 	 * Write a magic value to the thread structure
411 	 * to help identify valid ones:
412 	 */
413 	thread->magic = THR_MAGIC;
414 
415 	thread->cancel_enable = 1;
416 	thread->cancel_async = 0;
417 
418 	/* Initialize the mutex queues */
419 	for (i = 0; i < TMQ_NITEMS; i++)
420 		TAILQ_INIT(&thread->mq[i]);
421 
422 	thread->state = PS_RUNNING;
423 
424 	_thr_getscheduler(thread->tid, &thread->attr.sched_policy,
425 		 &sched_param);
426 	thread->attr.prio = sched_param.sched_priority;
427 
428 #ifdef _PTHREAD_FORCED_UNWIND
429 	thread->unwind_stackend = _usrstack;
430 #endif
431 
432 	/* Others cleared to zero by thr_alloc() */
433 }
434 
435 static void
436 init_private(void)
437 {
438 	struct rlimit rlim;
439 	size_t len;
440 	int mib[2];
441 	char *env, *env_bigstack, *env_splitstack;
442 
443 	_thr_umutex_init(&_mutex_static_lock);
444 	_thr_umutex_init(&_cond_static_lock);
445 	_thr_umutex_init(&_rwlock_static_lock);
446 	_thr_umutex_init(&_keytable_lock);
447 	_thr_urwlock_init(&_thr_atfork_lock);
448 	_thr_umutex_init(&_thr_event_lock);
449 	_thr_umutex_init(&_suspend_all_lock);
450 	_thr_spinlock_init();
451 	_thr_list_init();
452 	_thr_wake_addr_init();
453 	_sleepq_init();
454 	_single_thread = NULL;
455 	_suspend_all_waiters = 0;
456 
457 	/*
458 	 * Avoid reinitializing some things if they don't need to be,
459 	 * e.g. after a fork().
460 	 */
461 	if (init_once == 0) {
462 		__thr_pshared_init();
463 		/* Find the stack top */
464 		mib[0] = CTL_KERN;
465 		mib[1] = KERN_USRSTACK;
466 		len = sizeof (_usrstack);
467 		if (sysctl(mib, 2, &_usrstack, &len, NULL, 0) == -1)
468 			PANIC("Cannot get kern.usrstack from sysctl");
469 		env_bigstack = getenv("LIBPTHREAD_BIGSTACK_MAIN");
470 		env_splitstack = getenv("LIBPTHREAD_SPLITSTACK_MAIN");
471 		if (env_bigstack != NULL || env_splitstack == NULL) {
472 			if (getrlimit(RLIMIT_STACK, &rlim) == -1)
473 				PANIC("Cannot get stack rlimit");
474 			_thr_stack_initial = rlim.rlim_cur;
475 		}
476 		len = sizeof(_thr_is_smp);
477 		sysctlbyname("kern.smp.cpus", &_thr_is_smp, &len, NULL, 0);
478 		_thr_is_smp = (_thr_is_smp > 1);
479 		_thr_page_size = getpagesize();
480 		_thr_guard_default = _thr_page_size;
481 		_pthread_attr_default.guardsize_attr = _thr_guard_default;
482 		_pthread_attr_default.stacksize_attr = _thr_stack_default;
483 		env = getenv("LIBPTHREAD_SPINLOOPS");
484 		if (env)
485 			_thr_spinloops = atoi(env);
486 		env = getenv("LIBPTHREAD_YIELDLOOPS");
487 		if (env)
488 			_thr_yieldloops = atoi(env);
489 		env = getenv("LIBPTHREAD_QUEUE_FIFO");
490 		if (env)
491 			_thr_queuefifo = atoi(env);
492 		TAILQ_INIT(&_thr_atfork_list);
493 	}
494 	init_once = 1;
495 }
496