thr_init.c revision 297533
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 * $FreeBSD: stable/10/lib/libthr/thread/thr_init.c 297533 2016-04-04 06:49:20Z kib $ 34 */ 35 36#include "namespace.h" 37#include <sys/types.h> 38#include <sys/signalvar.h> 39#include <sys/ioctl.h> 40#include <sys/link_elf.h> 41#include <sys/resource.h> 42#include <sys/sysctl.h> 43#include <sys/ttycom.h> 44#include <sys/mman.h> 45#include <sys/rtprio.h> 46#include <errno.h> 47#include <fcntl.h> 48#include <paths.h> 49#include <pthread.h> 50#include <pthread_np.h> 51#include <signal.h> 52#include <stdlib.h> 53#include <string.h> 54#include <time.h> 55#include <unistd.h> 56#include "un-namespace.h" 57 58#include "libc_private.h" 59#include "thr_private.h" 60 61char *_usrstack; 62struct pthread *_thr_initial; 63int _libthr_debug; 64int _thread_event_mask; 65struct pthread *_thread_last_event; 66pthreadlist _thread_list = TAILQ_HEAD_INITIALIZER(_thread_list); 67pthreadlist _thread_gc_list = TAILQ_HEAD_INITIALIZER(_thread_gc_list); 68int _thread_active_threads = 1; 69atfork_head _thr_atfork_list = TAILQ_HEAD_INITIALIZER(_thr_atfork_list); 70struct urwlock _thr_atfork_lock = DEFAULT_URWLOCK; 71 72struct pthread_prio _thr_priorities[3] = { 73 {RTP_PRIO_MIN, RTP_PRIO_MAX, 0}, /* FIFO */ 74 {0, 0, 63}, /* OTHER */ 75 {RTP_PRIO_MIN, RTP_PRIO_MAX, 0} /* RR */ 76}; 77 78struct pthread_attr _pthread_attr_default = { 79 .sched_policy = SCHED_OTHER, 80 .sched_inherit = PTHREAD_INHERIT_SCHED, 81 .prio = 0, 82 .suspend = THR_CREATE_RUNNING, 83 .flags = PTHREAD_SCOPE_SYSTEM, 84 .stackaddr_attr = NULL, 85 .stacksize_attr = THR_STACK_DEFAULT, 86 .guardsize_attr = 0, 87 .cpusetsize = 0, 88 .cpuset = NULL 89}; 90 91struct pthread_mutex_attr _pthread_mutexattr_default = { 92 .m_type = PTHREAD_MUTEX_DEFAULT, 93 .m_protocol = PTHREAD_PRIO_NONE, 94 .m_ceiling = 0 95}; 96 97struct pthread_mutex_attr _pthread_mutexattr_adaptive_default = { 98 .m_type = PTHREAD_MUTEX_ADAPTIVE_NP, 99 .m_protocol = PTHREAD_PRIO_NONE, 100 .m_ceiling = 0 101}; 102 103/* Default condition variable attributes: */ 104struct pthread_cond_attr _pthread_condattr_default = { 105 .c_pshared = PTHREAD_PROCESS_PRIVATE, 106 .c_clockid = CLOCK_REALTIME 107}; 108 109pid_t _thr_pid; 110int _thr_is_smp = 0; 111size_t _thr_guard_default; 112size_t _thr_stack_default = THR_STACK_DEFAULT; 113size_t _thr_stack_initial = THR_STACK_INITIAL; 114int _thr_page_size; 115int _thr_spinloops; 116int _thr_yieldloops; 117int _thr_queuefifo = 4; 118int _gc_count; 119struct umutex _mutex_static_lock = DEFAULT_UMUTEX; 120struct umutex _cond_static_lock = DEFAULT_UMUTEX; 121struct umutex _rwlock_static_lock = DEFAULT_UMUTEX; 122struct umutex _keytable_lock = DEFAULT_UMUTEX; 123struct urwlock _thr_list_lock = DEFAULT_URWLOCK; 124struct umutex _thr_event_lock = DEFAULT_UMUTEX; 125struct umutex _suspend_all_lock = DEFAULT_UMUTEX; 126struct pthread *_single_thread; 127int _suspend_all_cycle; 128int _suspend_all_waiters; 129 130int __pthread_cond_wait(pthread_cond_t *, pthread_mutex_t *); 131int __pthread_mutex_lock(pthread_mutex_t *); 132int __pthread_mutex_trylock(pthread_mutex_t *); 133void _thread_init_hack(void) __attribute__ ((constructor)); 134 135static void init_private(void); 136static void init_main_thread(struct pthread *thread); 137 138/* 139 * All weak references used within libc should be in this table. 140 * This is so that static libraries will work. 141 */ 142 143STATIC_LIB_REQUIRE(_fork); 144STATIC_LIB_REQUIRE(_pthread_getspecific); 145STATIC_LIB_REQUIRE(_pthread_key_create); 146STATIC_LIB_REQUIRE(_pthread_key_delete); 147STATIC_LIB_REQUIRE(_pthread_mutex_destroy); 148STATIC_LIB_REQUIRE(_pthread_mutex_init); 149STATIC_LIB_REQUIRE(_pthread_mutex_lock); 150STATIC_LIB_REQUIRE(_pthread_mutex_trylock); 151STATIC_LIB_REQUIRE(_pthread_mutex_unlock); 152STATIC_LIB_REQUIRE(_pthread_mutexattr_init); 153STATIC_LIB_REQUIRE(_pthread_mutexattr_destroy); 154STATIC_LIB_REQUIRE(_pthread_mutexattr_settype); 155STATIC_LIB_REQUIRE(_pthread_once); 156STATIC_LIB_REQUIRE(_pthread_setspecific); 157STATIC_LIB_REQUIRE(_raise); 158STATIC_LIB_REQUIRE(_sem_destroy); 159STATIC_LIB_REQUIRE(_sem_getvalue); 160STATIC_LIB_REQUIRE(_sem_init); 161STATIC_LIB_REQUIRE(_sem_post); 162STATIC_LIB_REQUIRE(_sem_timedwait); 163STATIC_LIB_REQUIRE(_sem_trywait); 164STATIC_LIB_REQUIRE(_sem_wait); 165STATIC_LIB_REQUIRE(_sigaction); 166STATIC_LIB_REQUIRE(_sigprocmask); 167STATIC_LIB_REQUIRE(_sigsuspend); 168STATIC_LIB_REQUIRE(_sigtimedwait); 169STATIC_LIB_REQUIRE(_sigwait); 170STATIC_LIB_REQUIRE(_sigwaitinfo); 171STATIC_LIB_REQUIRE(_spinlock); 172STATIC_LIB_REQUIRE(_spinlock_debug); 173STATIC_LIB_REQUIRE(_spinunlock); 174STATIC_LIB_REQUIRE(_thread_init_hack); 175 176/* 177 * These are needed when linking statically. All references within 178 * libgcc (and in the future libc) to these routines are weak, but 179 * if they are not (strongly) referenced by the application or other 180 * libraries, then the actual functions will not be loaded. 181 */ 182STATIC_LIB_REQUIRE(_pthread_once); 183STATIC_LIB_REQUIRE(_pthread_key_create); 184STATIC_LIB_REQUIRE(_pthread_key_delete); 185STATIC_LIB_REQUIRE(_pthread_getspecific); 186STATIC_LIB_REQUIRE(_pthread_setspecific); 187STATIC_LIB_REQUIRE(_pthread_mutex_init); 188STATIC_LIB_REQUIRE(_pthread_mutex_destroy); 189STATIC_LIB_REQUIRE(_pthread_mutex_lock); 190STATIC_LIB_REQUIRE(_pthread_mutex_trylock); 191STATIC_LIB_REQUIRE(_pthread_mutex_unlock); 192STATIC_LIB_REQUIRE(_pthread_create); 193 194/* Pull in all symbols required by libthread_db */ 195STATIC_LIB_REQUIRE(_thread_state_running); 196 197#define DUAL_ENTRY(entry) \ 198 (pthread_func_t)entry, (pthread_func_t)entry 199 200static pthread_func_t jmp_table[][2] = { 201 {DUAL_ENTRY(_pthread_atfork)}, /* PJT_ATFORK */ 202 {DUAL_ENTRY(_pthread_attr_destroy)}, /* PJT_ATTR_DESTROY */ 203 {DUAL_ENTRY(_pthread_attr_getdetachstate)}, /* PJT_ATTR_GETDETACHSTATE */ 204 {DUAL_ENTRY(_pthread_attr_getguardsize)}, /* PJT_ATTR_GETGUARDSIZE */ 205 {DUAL_ENTRY(_pthread_attr_getinheritsched)}, /* PJT_ATTR_GETINHERITSCHED */ 206 {DUAL_ENTRY(_pthread_attr_getschedparam)}, /* PJT_ATTR_GETSCHEDPARAM */ 207 {DUAL_ENTRY(_pthread_attr_getschedpolicy)}, /* PJT_ATTR_GETSCHEDPOLICY */ 208 {DUAL_ENTRY(_pthread_attr_getscope)}, /* PJT_ATTR_GETSCOPE */ 209 {DUAL_ENTRY(_pthread_attr_getstackaddr)}, /* PJT_ATTR_GETSTACKADDR */ 210 {DUAL_ENTRY(_pthread_attr_getstacksize)}, /* PJT_ATTR_GETSTACKSIZE */ 211 {DUAL_ENTRY(_pthread_attr_init)}, /* PJT_ATTR_INIT */ 212 {DUAL_ENTRY(_pthread_attr_setdetachstate)}, /* PJT_ATTR_SETDETACHSTATE */ 213 {DUAL_ENTRY(_pthread_attr_setguardsize)}, /* PJT_ATTR_SETGUARDSIZE */ 214 {DUAL_ENTRY(_pthread_attr_setinheritsched)}, /* PJT_ATTR_SETINHERITSCHED */ 215 {DUAL_ENTRY(_pthread_attr_setschedparam)}, /* PJT_ATTR_SETSCHEDPARAM */ 216 {DUAL_ENTRY(_pthread_attr_setschedpolicy)}, /* PJT_ATTR_SETSCHEDPOLICY */ 217 {DUAL_ENTRY(_pthread_attr_setscope)}, /* PJT_ATTR_SETSCOPE */ 218 {DUAL_ENTRY(_pthread_attr_setstackaddr)}, /* PJT_ATTR_SETSTACKADDR */ 219 {DUAL_ENTRY(_pthread_attr_setstacksize)}, /* PJT_ATTR_SETSTACKSIZE */ 220 {DUAL_ENTRY(_pthread_cancel)}, /* PJT_CANCEL */ 221 {DUAL_ENTRY(_pthread_cleanup_pop)}, /* PJT_CLEANUP_POP */ 222 {DUAL_ENTRY(_pthread_cleanup_push)}, /* PJT_CLEANUP_PUSH */ 223 {DUAL_ENTRY(_pthread_cond_broadcast)}, /* PJT_COND_BROADCAST */ 224 {DUAL_ENTRY(_pthread_cond_destroy)}, /* PJT_COND_DESTROY */ 225 {DUAL_ENTRY(_pthread_cond_init)}, /* PJT_COND_INIT */ 226 {DUAL_ENTRY(_pthread_cond_signal)}, /* PJT_COND_SIGNAL */ 227 {DUAL_ENTRY(_pthread_cond_timedwait)}, /* PJT_COND_TIMEDWAIT */ 228 {(pthread_func_t)__pthread_cond_wait, 229 (pthread_func_t)_pthread_cond_wait}, /* PJT_COND_WAIT */ 230 {DUAL_ENTRY(_pthread_detach)}, /* PJT_DETACH */ 231 {DUAL_ENTRY(_pthread_equal)}, /* PJT_EQUAL */ 232 {DUAL_ENTRY(_pthread_exit)}, /* PJT_EXIT */ 233 {DUAL_ENTRY(_pthread_getspecific)}, /* PJT_GETSPECIFIC */ 234 {DUAL_ENTRY(_pthread_join)}, /* PJT_JOIN */ 235 {DUAL_ENTRY(_pthread_key_create)}, /* PJT_KEY_CREATE */ 236 {DUAL_ENTRY(_pthread_key_delete)}, /* PJT_KEY_DELETE*/ 237 {DUAL_ENTRY(_pthread_kill)}, /* PJT_KILL */ 238 {DUAL_ENTRY(_pthread_main_np)}, /* PJT_MAIN_NP */ 239 {DUAL_ENTRY(_pthread_mutexattr_destroy)}, /* PJT_MUTEXATTR_DESTROY */ 240 {DUAL_ENTRY(_pthread_mutexattr_init)}, /* PJT_MUTEXATTR_INIT */ 241 {DUAL_ENTRY(_pthread_mutexattr_settype)}, /* PJT_MUTEXATTR_SETTYPE */ 242 {DUAL_ENTRY(_pthread_mutex_destroy)}, /* PJT_MUTEX_DESTROY */ 243 {DUAL_ENTRY(_pthread_mutex_init)}, /* PJT_MUTEX_INIT */ 244 {(pthread_func_t)__pthread_mutex_lock, 245 (pthread_func_t)_pthread_mutex_lock}, /* PJT_MUTEX_LOCK */ 246 {(pthread_func_t)__pthread_mutex_trylock, 247 (pthread_func_t)_pthread_mutex_trylock},/* PJT_MUTEX_TRYLOCK */ 248 {DUAL_ENTRY(_pthread_mutex_unlock)}, /* PJT_MUTEX_UNLOCK */ 249 {DUAL_ENTRY(_pthread_once)}, /* PJT_ONCE */ 250 {DUAL_ENTRY(_pthread_rwlock_destroy)}, /* PJT_RWLOCK_DESTROY */ 251 {DUAL_ENTRY(_pthread_rwlock_init)}, /* PJT_RWLOCK_INIT */ 252 {DUAL_ENTRY(_pthread_rwlock_rdlock)}, /* PJT_RWLOCK_RDLOCK */ 253 {DUAL_ENTRY(_pthread_rwlock_tryrdlock)},/* PJT_RWLOCK_TRYRDLOCK */ 254 {DUAL_ENTRY(_pthread_rwlock_trywrlock)},/* PJT_RWLOCK_TRYWRLOCK */ 255 {DUAL_ENTRY(_pthread_rwlock_unlock)}, /* PJT_RWLOCK_UNLOCK */ 256 {DUAL_ENTRY(_pthread_rwlock_wrlock)}, /* PJT_RWLOCK_WRLOCK */ 257 {DUAL_ENTRY(_pthread_self)}, /* PJT_SELF */ 258 {DUAL_ENTRY(_pthread_setcancelstate)}, /* PJT_SETCANCELSTATE */ 259 {DUAL_ENTRY(_pthread_setcanceltype)}, /* PJT_SETCANCELTYPE */ 260 {DUAL_ENTRY(_pthread_setspecific)}, /* PJT_SETSPECIFIC */ 261 {DUAL_ENTRY(_pthread_sigmask)}, /* PJT_SIGMASK */ 262 {DUAL_ENTRY(_pthread_testcancel)}, /* PJT_TESTCANCEL */ 263 {DUAL_ENTRY(__pthread_cleanup_pop_imp)},/* PJT_CLEANUP_POP_IMP */ 264 {DUAL_ENTRY(__pthread_cleanup_push_imp)},/* PJT_CLEANUP_PUSH_IMP */ 265 {DUAL_ENTRY(_pthread_cancel_enter)}, /* PJT_CANCEL_ENTER */ 266 {DUAL_ENTRY(_pthread_cancel_leave)} /* PJT_CANCEL_LEAVE */ 267}; 268 269static int init_once = 0; 270 271/* 272 * For the shared version of the threads library, the above is sufficient. 273 * But for the archive version of the library, we need a little bit more. 274 * Namely, we must arrange for this particular module to be pulled in from 275 * the archive library at link time. To accomplish that, we define and 276 * initialize a variable, "_thread_autoinit_dummy_decl". This variable is 277 * referenced (as an extern) from libc/stdlib/exit.c. This will always 278 * create a need for this module, ensuring that it is present in the 279 * executable. 280 */ 281extern int _thread_autoinit_dummy_decl; 282int _thread_autoinit_dummy_decl = 0; 283 284void 285_thread_init_hack(void) 286{ 287 288 _libpthread_init(NULL); 289} 290 291 292/* 293 * Threaded process initialization. 294 * 295 * This is only called under two conditions: 296 * 297 * 1) Some thread routines have detected that the library hasn't yet 298 * been initialized (_thr_initial == NULL && curthread == NULL), or 299 * 300 * 2) An explicit call to reinitialize after a fork (indicated 301 * by curthread != NULL) 302 */ 303void 304_libpthread_init(struct pthread *curthread) 305{ 306 int first, dlopened; 307 308 /* Check if this function has already been called: */ 309 if ((_thr_initial != NULL) && (curthread == NULL)) 310 /* Only initialize the threaded application once. */ 311 return; 312 313 /* 314 * Check the size of the jump table to make sure it is preset 315 * with the correct number of entries. 316 */ 317 if (sizeof(jmp_table) != (sizeof(pthread_func_t) * PJT_MAX * 2)) 318 PANIC("Thread jump table not properly initialized"); 319 memcpy(__thr_jtable, jmp_table, sizeof(jmp_table)); 320 __thr_interpose_libc(); 321 322 /* Initialize pthread private data. */ 323 init_private(); 324 325 /* Set the initial thread. */ 326 if (curthread == NULL) { 327 first = 1; 328 /* Create and initialize the initial thread. */ 329 curthread = _thr_alloc(NULL); 330 if (curthread == NULL) 331 PANIC("Can't allocate initial thread"); 332 init_main_thread(curthread); 333 } else { 334 first = 0; 335 } 336 337 /* 338 * Add the thread to the thread list queue. 339 */ 340 THR_LIST_ADD(curthread); 341 _thread_active_threads = 1; 342 343 /* Setup the thread specific data */ 344 _tcb_set(curthread->tcb); 345 346 if (first) { 347 _thr_initial = curthread; 348 dlopened = _rtld_is_dlopened(&_thread_autoinit_dummy_decl) != 0; 349 _thr_signal_init(dlopened); 350 if (_thread_event_mask & TD_CREATE) 351 _thr_report_creation(curthread, curthread); 352 /* 353 * Always use our rtld lock implementation. 354 * It is faster because it postpones signal handlers 355 * instead of calling sigprocmask(2). 356 */ 357 _thr_rtld_init(); 358 } 359} 360 361/* 362 * This function and pthread_create() do a lot of the same things. 363 * It'd be nice to consolidate the common stuff in one place. 364 */ 365static void 366init_main_thread(struct pthread *thread) 367{ 368 struct sched_param sched_param; 369 370 /* Setup the thread attributes. */ 371 thr_self(&thread->tid); 372 thread->attr = _pthread_attr_default; 373 /* 374 * Set up the thread stack. 375 * 376 * Create a red zone below the main stack. All other stacks 377 * are constrained to a maximum size by the parameters 378 * passed to mmap(), but this stack is only limited by 379 * resource limits, so this stack needs an explicitly mapped 380 * red zone to protect the thread stack that is just beyond. 381 */ 382 if (mmap(_usrstack - _thr_stack_initial - 383 _thr_guard_default, _thr_guard_default, 0, MAP_ANON, 384 -1, 0) == MAP_FAILED) 385 PANIC("Cannot allocate red zone for initial thread"); 386 387 /* 388 * Mark the stack as an application supplied stack so that it 389 * isn't deallocated. 390 * 391 * XXX - I'm not sure it would hurt anything to deallocate 392 * the main thread stack because deallocation doesn't 393 * actually free() it; it just puts it in the free 394 * stack queue for later reuse. 395 */ 396 thread->attr.stackaddr_attr = _usrstack - _thr_stack_initial; 397 thread->attr.stacksize_attr = _thr_stack_initial; 398 thread->attr.guardsize_attr = _thr_guard_default; 399 thread->attr.flags |= THR_STACK_USER; 400 401 /* 402 * Write a magic value to the thread structure 403 * to help identify valid ones: 404 */ 405 thread->magic = THR_MAGIC; 406 407 thread->cancel_enable = 1; 408 thread->cancel_async = 0; 409 410 /* Initialize the mutex queue: */ 411 TAILQ_INIT(&thread->mutexq); 412 TAILQ_INIT(&thread->pp_mutexq); 413 414 thread->state = PS_RUNNING; 415 416 _thr_getscheduler(thread->tid, &thread->attr.sched_policy, 417 &sched_param); 418 thread->attr.prio = sched_param.sched_priority; 419 420#ifdef _PTHREAD_FORCED_UNWIND 421 thread->unwind_stackend = _usrstack; 422#endif 423 424 /* Others cleared to zero by thr_alloc() */ 425} 426 427static void 428init_private(void) 429{ 430 struct rlimit rlim; 431 size_t len; 432 int mib[2]; 433 char *env, *env_bigstack, *env_splitstack; 434 435 _thr_umutex_init(&_mutex_static_lock); 436 _thr_umutex_init(&_cond_static_lock); 437 _thr_umutex_init(&_rwlock_static_lock); 438 _thr_umutex_init(&_keytable_lock); 439 _thr_urwlock_init(&_thr_atfork_lock); 440 _thr_umutex_init(&_thr_event_lock); 441 _thr_umutex_init(&_suspend_all_lock); 442 _thr_once_init(); 443 _thr_spinlock_init(); 444 _thr_list_init(); 445 _thr_wake_addr_init(); 446 _sleepq_init(); 447 _single_thread = NULL; 448 _suspend_all_waiters = 0; 449 450 /* 451 * Avoid reinitializing some things if they don't need to be, 452 * e.g. after a fork(). 453 */ 454 if (init_once == 0) { 455 /* Find the stack top */ 456 mib[0] = CTL_KERN; 457 mib[1] = KERN_USRSTACK; 458 len = sizeof (_usrstack); 459 if (sysctl(mib, 2, &_usrstack, &len, NULL, 0) == -1) 460 PANIC("Cannot get kern.usrstack from sysctl"); 461 env_bigstack = getenv("LIBPTHREAD_BIGSTACK_MAIN"); 462 env_splitstack = getenv("LIBPTHREAD_SPLITSTACK_MAIN"); 463 if (env_bigstack != NULL || env_splitstack == NULL) { 464 if (getrlimit(RLIMIT_STACK, &rlim) == -1) 465 PANIC("Cannot get stack rlimit"); 466 _thr_stack_initial = rlim.rlim_cur; 467 } 468 len = sizeof(_thr_is_smp); 469 sysctlbyname("kern.smp.cpus", &_thr_is_smp, &len, NULL, 0); 470 _thr_is_smp = (_thr_is_smp > 1); 471 _thr_page_size = getpagesize(); 472 _thr_guard_default = _thr_page_size; 473 _pthread_attr_default.guardsize_attr = _thr_guard_default; 474 _pthread_attr_default.stacksize_attr = _thr_stack_default; 475 env = getenv("LIBPTHREAD_SPINLOOPS"); 476 if (env) 477 _thr_spinloops = atoi(env); 478 env = getenv("LIBPTHREAD_YIELDLOOPS"); 479 if (env) 480 _thr_yieldloops = atoi(env); 481 env = getenv("LIBPTHREAD_QUEUE_FIFO"); 482 if (env) 483 _thr_queuefifo = atoi(env); 484 TAILQ_INIT(&_thr_atfork_list); 485 } 486 init_once = 1; 487} 488