xref: /freebsd/lib/libthr/thread/thr_init.c (revision a2aef24aa3c8458e4036735dd6928b4ef77294e5)
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(_spinunlock);
177 STATIC_LIB_REQUIRE(_thread_init_hack);
178 
179 /*
180  * These are needed when linking statically.  All references within
181  * libgcc (and in the future libc) to these routines are weak, but
182  * if they are not (strongly) referenced by the application or other
183  * libraries, then the actual functions will not be loaded.
184  */
185 STATIC_LIB_REQUIRE(_pthread_once);
186 STATIC_LIB_REQUIRE(_pthread_key_create);
187 STATIC_LIB_REQUIRE(_pthread_key_delete);
188 STATIC_LIB_REQUIRE(_pthread_getspecific);
189 STATIC_LIB_REQUIRE(_pthread_setspecific);
190 STATIC_LIB_REQUIRE(_pthread_mutex_init);
191 STATIC_LIB_REQUIRE(_pthread_mutex_destroy);
192 STATIC_LIB_REQUIRE(_pthread_mutex_lock);
193 STATIC_LIB_REQUIRE(_pthread_mutex_trylock);
194 STATIC_LIB_REQUIRE(_pthread_mutex_unlock);
195 STATIC_LIB_REQUIRE(_pthread_create);
196 
197 /* Pull in all symbols required by libthread_db */
198 STATIC_LIB_REQUIRE(_thread_state_running);
199 
200 #define	DUAL_ENTRY(entry)	\
201 	(pthread_func_t)entry, (pthread_func_t)entry
202 
203 static pthread_func_t jmp_table[][2] = {
204 	{DUAL_ENTRY(_pthread_atfork)},	/* PJT_ATFORK */
205 	{DUAL_ENTRY(_pthread_attr_destroy)},	/* PJT_ATTR_DESTROY */
206 	{DUAL_ENTRY(_pthread_attr_getdetachstate)},	/* PJT_ATTR_GETDETACHSTATE */
207 	{DUAL_ENTRY(_pthread_attr_getguardsize)},	/* PJT_ATTR_GETGUARDSIZE */
208 	{DUAL_ENTRY(_pthread_attr_getinheritsched)},	/* PJT_ATTR_GETINHERITSCHED */
209 	{DUAL_ENTRY(_pthread_attr_getschedparam)},	/* PJT_ATTR_GETSCHEDPARAM */
210 	{DUAL_ENTRY(_pthread_attr_getschedpolicy)},	/* PJT_ATTR_GETSCHEDPOLICY */
211 	{DUAL_ENTRY(_pthread_attr_getscope)},	/* PJT_ATTR_GETSCOPE */
212 	{DUAL_ENTRY(_pthread_attr_getstackaddr)},	/* PJT_ATTR_GETSTACKADDR */
213 	{DUAL_ENTRY(_pthread_attr_getstacksize)},	/* PJT_ATTR_GETSTACKSIZE */
214 	{DUAL_ENTRY(_pthread_attr_init)},	/* PJT_ATTR_INIT */
215 	{DUAL_ENTRY(_pthread_attr_setdetachstate)},	/* PJT_ATTR_SETDETACHSTATE */
216 	{DUAL_ENTRY(_pthread_attr_setguardsize)},	/* PJT_ATTR_SETGUARDSIZE */
217 	{DUAL_ENTRY(_pthread_attr_setinheritsched)},	/* PJT_ATTR_SETINHERITSCHED */
218 	{DUAL_ENTRY(_pthread_attr_setschedparam)},	/* PJT_ATTR_SETSCHEDPARAM */
219 	{DUAL_ENTRY(_pthread_attr_setschedpolicy)},	/* PJT_ATTR_SETSCHEDPOLICY */
220 	{DUAL_ENTRY(_pthread_attr_setscope)},	/* PJT_ATTR_SETSCOPE */
221 	{DUAL_ENTRY(_pthread_attr_setstackaddr)},	/* PJT_ATTR_SETSTACKADDR */
222 	{DUAL_ENTRY(_pthread_attr_setstacksize)},	/* PJT_ATTR_SETSTACKSIZE */
223 	{DUAL_ENTRY(_pthread_cancel)},	/* PJT_CANCEL */
224 	{DUAL_ENTRY(_pthread_cleanup_pop)},	/* PJT_CLEANUP_POP */
225 	{DUAL_ENTRY(_pthread_cleanup_push)},	/* PJT_CLEANUP_PUSH */
226 	{DUAL_ENTRY(_pthread_cond_broadcast)},	/* PJT_COND_BROADCAST */
227 	{DUAL_ENTRY(_pthread_cond_destroy)},	/* PJT_COND_DESTROY */
228 	{DUAL_ENTRY(_pthread_cond_init)},	/* PJT_COND_INIT */
229 	{DUAL_ENTRY(_pthread_cond_signal)},	/* PJT_COND_SIGNAL */
230 	{DUAL_ENTRY(_pthread_cond_timedwait)},	/* PJT_COND_TIMEDWAIT */
231 	{(pthread_func_t)__pthread_cond_wait,
232 	 (pthread_func_t)_pthread_cond_wait},	/* PJT_COND_WAIT */
233 	{DUAL_ENTRY(_pthread_detach)},	/* PJT_DETACH */
234 	{DUAL_ENTRY(_pthread_equal)},	/* PJT_EQUAL */
235 	{DUAL_ENTRY(_pthread_exit)},	/* PJT_EXIT */
236 	{DUAL_ENTRY(_pthread_getspecific)},	/* PJT_GETSPECIFIC */
237 	{DUAL_ENTRY(_pthread_join)},	/* PJT_JOIN */
238 	{DUAL_ENTRY(_pthread_key_create)},	/* PJT_KEY_CREATE */
239 	{DUAL_ENTRY(_pthread_key_delete)},	/* PJT_KEY_DELETE*/
240 	{DUAL_ENTRY(_pthread_kill)},	/* PJT_KILL */
241 	{DUAL_ENTRY(_pthread_main_np)},		/* PJT_MAIN_NP */
242 	{DUAL_ENTRY(_pthread_mutexattr_destroy)}, /* PJT_MUTEXATTR_DESTROY */
243 	{DUAL_ENTRY(_pthread_mutexattr_init)},	/* PJT_MUTEXATTR_INIT */
244 	{DUAL_ENTRY(_pthread_mutexattr_settype)}, /* PJT_MUTEXATTR_SETTYPE */
245 	{DUAL_ENTRY(_pthread_mutex_destroy)},	/* PJT_MUTEX_DESTROY */
246 	{DUAL_ENTRY(_pthread_mutex_init)},	/* PJT_MUTEX_INIT */
247 	{(pthread_func_t)__pthread_mutex_lock,
248 	 (pthread_func_t)_pthread_mutex_lock},	/* PJT_MUTEX_LOCK */
249 	{(pthread_func_t)__pthread_mutex_trylock,
250 	 (pthread_func_t)_pthread_mutex_trylock},/* PJT_MUTEX_TRYLOCK */
251 	{DUAL_ENTRY(_pthread_mutex_unlock)},	/* PJT_MUTEX_UNLOCK */
252 	{DUAL_ENTRY(_pthread_once)},		/* PJT_ONCE */
253 	{DUAL_ENTRY(_pthread_rwlock_destroy)},	/* PJT_RWLOCK_DESTROY */
254 	{DUAL_ENTRY(_pthread_rwlock_init)},	/* PJT_RWLOCK_INIT */
255 	{DUAL_ENTRY(_pthread_rwlock_rdlock)},	/* PJT_RWLOCK_RDLOCK */
256 	{DUAL_ENTRY(_pthread_rwlock_tryrdlock)},/* PJT_RWLOCK_TRYRDLOCK */
257 	{DUAL_ENTRY(_pthread_rwlock_trywrlock)},/* PJT_RWLOCK_TRYWRLOCK */
258 	{DUAL_ENTRY(_pthread_rwlock_unlock)},	/* PJT_RWLOCK_UNLOCK */
259 	{DUAL_ENTRY(_pthread_rwlock_wrlock)},	/* PJT_RWLOCK_WRLOCK */
260 	{DUAL_ENTRY(_pthread_self)},		/* PJT_SELF */
261 	{DUAL_ENTRY(_pthread_setcancelstate)},	/* PJT_SETCANCELSTATE */
262 	{DUAL_ENTRY(_pthread_setcanceltype)},	/* PJT_SETCANCELTYPE */
263 	{DUAL_ENTRY(_pthread_setspecific)},	/* PJT_SETSPECIFIC */
264 	{DUAL_ENTRY(_pthread_sigmask)},		/* PJT_SIGMASK */
265 	{DUAL_ENTRY(_pthread_testcancel)},	/* PJT_TESTCANCEL */
266 	{DUAL_ENTRY(__pthread_cleanup_pop_imp)},/* PJT_CLEANUP_POP_IMP */
267 	{DUAL_ENTRY(__pthread_cleanup_push_imp)},/* PJT_CLEANUP_PUSH_IMP */
268 	{DUAL_ENTRY(_pthread_cancel_enter)},	/* PJT_CANCEL_ENTER */
269 	{DUAL_ENTRY(_pthread_cancel_leave)},	/* PJT_CANCEL_LEAVE */
270 	{DUAL_ENTRY(_pthread_mutex_consistent)},/* PJT_MUTEX_CONSISTENT */
271 	{DUAL_ENTRY(_pthread_mutexattr_getrobust)},/* PJT_MUTEXATTR_GETROBUST */
272 	{DUAL_ENTRY(_pthread_mutexattr_setrobust)},/* PJT_MUTEXATTR_SETROBUST */
273 };
274 
275 static int init_once = 0;
276 
277 /*
278  * For the shared version of the threads library, the above is sufficient.
279  * But for the archive version of the library, we need a little bit more.
280  * Namely, we must arrange for this particular module to be pulled in from
281  * the archive library at link time.  To accomplish that, we define and
282  * initialize a variable, "_thread_autoinit_dummy_decl".  This variable is
283  * referenced (as an extern) from libc/stdlib/exit.c. This will always
284  * create a need for this module, ensuring that it is present in the
285  * executable.
286  */
287 extern int _thread_autoinit_dummy_decl;
288 int _thread_autoinit_dummy_decl = 0;
289 
290 void
291 _thread_init_hack(void)
292 {
293 
294 	_libpthread_init(NULL);
295 }
296 
297 
298 /*
299  * Threaded process initialization.
300  *
301  * This is only called under two conditions:
302  *
303  *   1) Some thread routines have detected that the library hasn't yet
304  *      been initialized (_thr_initial == NULL && curthread == NULL), or
305  *
306  *   2) An explicit call to reinitialize after a fork (indicated
307  *      by curthread != NULL)
308  */
309 void
310 _libpthread_init(struct pthread *curthread)
311 {
312 	int first, dlopened;
313 
314 	/* Check if this function has already been called: */
315 	if (_thr_initial != NULL && curthread == NULL)
316 		/* Only initialize the threaded application once. */
317 		return;
318 
319 	/*
320 	 * Check the size of the jump table to make sure it is preset
321 	 * with the correct number of entries.
322 	 */
323 	if (sizeof(jmp_table) != sizeof(pthread_func_t) * PJT_MAX * 2)
324 		PANIC("Thread jump table not properly initialized");
325 	memcpy(__thr_jtable, jmp_table, sizeof(jmp_table));
326 	__thr_interpose_libc();
327 
328 	/* Initialize pthread private data. */
329 	init_private();
330 
331 	/* Set the initial thread. */
332 	if (curthread == NULL) {
333 		first = 1;
334 		/* Create and initialize the initial thread. */
335 		curthread = _thr_alloc(NULL);
336 		if (curthread == NULL)
337 			PANIC("Can't allocate initial thread");
338 		init_main_thread(curthread);
339 	} else {
340 		first = 0;
341 	}
342 
343 	/*
344 	 * Add the thread to the thread list queue.
345 	 */
346 	THR_LIST_ADD(curthread);
347 	_thread_active_threads = 1;
348 
349 	/* Setup the thread specific data */
350 	_tcb_set(curthread->tcb);
351 
352 	if (first) {
353 		_thr_initial = curthread;
354 		dlopened = _rtld_is_dlopened(&_thread_autoinit_dummy_decl) != 0;
355 		_thr_signal_init(dlopened);
356 		if (_thread_event_mask & TD_CREATE)
357 			_thr_report_creation(curthread, curthread);
358 		/*
359 		 * Always use our rtld lock implementation.
360 		 * It is faster because it postpones signal handlers
361 		 * instead of calling sigprocmask(2).
362 		 */
363 		_thr_rtld_init();
364 	}
365 }
366 
367 /*
368  * This function and pthread_create() do a lot of the same things.
369  * It'd be nice to consolidate the common stuff in one place.
370  */
371 static void
372 init_main_thread(struct pthread *thread)
373 {
374 	struct sched_param sched_param;
375 	int i;
376 
377 	/* Setup the thread attributes. */
378 	thr_self(&thread->tid);
379 	thread->attr = _pthread_attr_default;
380 	/*
381 	 * Set up the thread stack.
382 	 *
383 	 * Create a red zone below the main stack.  All other stacks
384 	 * are constrained to a maximum size by the parameters
385 	 * passed to mmap(), but this stack is only limited by
386 	 * resource limits, so this stack needs an explicitly mapped
387 	 * red zone to protect the thread stack that is just beyond.
388 	 */
389 	if (mmap(_usrstack - _thr_stack_initial -
390 	    _thr_guard_default, _thr_guard_default, 0, MAP_ANON,
391 	    -1, 0) == MAP_FAILED)
392 		PANIC("Cannot allocate red zone for initial thread");
393 
394 	/*
395 	 * Mark the stack as an application supplied stack so that it
396 	 * isn't deallocated.
397 	 *
398 	 * XXX - I'm not sure it would hurt anything to deallocate
399 	 *       the main thread stack because deallocation doesn't
400 	 *       actually free() it; it just puts it in the free
401 	 *       stack queue for later reuse.
402 	 */
403 	thread->attr.stackaddr_attr = _usrstack - _thr_stack_initial;
404 	thread->attr.stacksize_attr = _thr_stack_initial;
405 	thread->attr.guardsize_attr = _thr_guard_default;
406 	thread->attr.flags |= THR_STACK_USER;
407 
408 	/*
409 	 * Write a magic value to the thread structure
410 	 * to help identify valid ones:
411 	 */
412 	thread->magic = THR_MAGIC;
413 
414 	thread->cancel_enable = 1;
415 	thread->cancel_async = 0;
416 
417 	/* Initialize the mutex queues */
418 	for (i = 0; i < TMQ_NITEMS; i++)
419 		TAILQ_INIT(&thread->mq[i]);
420 
421 	thread->state = PS_RUNNING;
422 
423 	_thr_getscheduler(thread->tid, &thread->attr.sched_policy,
424 		 &sched_param);
425 	thread->attr.prio = sched_param.sched_priority;
426 
427 #ifdef _PTHREAD_FORCED_UNWIND
428 	thread->unwind_stackend = _usrstack;
429 #endif
430 
431 	/* Others cleared to zero by thr_alloc() */
432 }
433 
434 static void
435 init_private(void)
436 {
437 	struct rlimit rlim;
438 	size_t len;
439 	int mib[2];
440 	char *env, *env_bigstack, *env_splitstack;
441 
442 	_thr_umutex_init(&_mutex_static_lock);
443 	_thr_umutex_init(&_cond_static_lock);
444 	_thr_umutex_init(&_rwlock_static_lock);
445 	_thr_umutex_init(&_keytable_lock);
446 	_thr_urwlock_init(&_thr_atfork_lock);
447 	_thr_umutex_init(&_thr_event_lock);
448 	_thr_umutex_init(&_suspend_all_lock);
449 	_thr_spinlock_init();
450 	_thr_list_init();
451 	_thr_wake_addr_init();
452 	_sleepq_init();
453 	_single_thread = NULL;
454 	_suspend_all_waiters = 0;
455 
456 	/*
457 	 * Avoid reinitializing some things if they don't need to be,
458 	 * e.g. after a fork().
459 	 */
460 	if (init_once == 0) {
461 		__thr_pshared_init();
462 		/* Find the stack top */
463 		mib[0] = CTL_KERN;
464 		mib[1] = KERN_USRSTACK;
465 		len = sizeof (_usrstack);
466 		if (sysctl(mib, 2, &_usrstack, &len, NULL, 0) == -1)
467 			PANIC("Cannot get kern.usrstack from sysctl");
468 		env_bigstack = getenv("LIBPTHREAD_BIGSTACK_MAIN");
469 		env_splitstack = getenv("LIBPTHREAD_SPLITSTACK_MAIN");
470 		if (env_bigstack != NULL || env_splitstack == NULL) {
471 			if (getrlimit(RLIMIT_STACK, &rlim) == -1)
472 				PANIC("Cannot get stack rlimit");
473 			_thr_stack_initial = rlim.rlim_cur;
474 		}
475 		len = sizeof(_thr_is_smp);
476 		sysctlbyname("kern.smp.cpus", &_thr_is_smp, &len, NULL, 0);
477 		_thr_is_smp = (_thr_is_smp > 1);
478 		_thr_page_size = getpagesize();
479 		_thr_guard_default = _thr_page_size;
480 		_pthread_attr_default.guardsize_attr = _thr_guard_default;
481 		_pthread_attr_default.stacksize_attr = _thr_stack_default;
482 		env = getenv("LIBPTHREAD_SPINLOOPS");
483 		if (env)
484 			_thr_spinloops = atoi(env);
485 		env = getenv("LIBPTHREAD_YIELDLOOPS");
486 		if (env)
487 			_thr_yieldloops = atoi(env);
488 		env = getenv("LIBPTHREAD_QUEUE_FIFO");
489 		if (env)
490 			_thr_queuefifo = atoi(env);
491 		TAILQ_INIT(&_thr_atfork_list);
492 	}
493 	init_once = 1;
494 }
495