thr_init.c revision 297814
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 297814 2016-04-11 09:29:08Z 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 109int _thr_is_smp = 0; 110size_t _thr_guard_default; 111size_t _thr_stack_default = THR_STACK_DEFAULT; 112size_t _thr_stack_initial = THR_STACK_INITIAL; 113int _thr_page_size; 114int _thr_spinloops; 115int _thr_yieldloops; 116int _thr_queuefifo = 4; 117int _gc_count; 118struct umutex _mutex_static_lock = DEFAULT_UMUTEX; 119struct umutex _cond_static_lock = DEFAULT_UMUTEX; 120struct umutex _rwlock_static_lock = DEFAULT_UMUTEX; 121struct umutex _keytable_lock = DEFAULT_UMUTEX; 122struct urwlock _thr_list_lock = DEFAULT_URWLOCK; 123struct umutex _thr_event_lock = DEFAULT_UMUTEX; 124struct umutex _suspend_all_lock = DEFAULT_UMUTEX; 125struct pthread *_single_thread; 126int _suspend_all_cycle; 127int _suspend_all_waiters; 128 129int __pthread_cond_wait(pthread_cond_t *, pthread_mutex_t *); 130int __pthread_mutex_lock(pthread_mutex_t *); 131int __pthread_mutex_trylock(pthread_mutex_t *); 132void _thread_init_hack(void) __attribute__ ((constructor)); 133 134static void init_private(void); 135static void init_main_thread(struct pthread *thread); 136 137/* 138 * All weak references used within libc should be in this table. 139 * This is so that static libraries will work. 140 */ 141 142STATIC_LIB_REQUIRE(_fork); 143STATIC_LIB_REQUIRE(_pthread_getspecific); 144STATIC_LIB_REQUIRE(_pthread_key_create); 145STATIC_LIB_REQUIRE(_pthread_key_delete); 146STATIC_LIB_REQUIRE(_pthread_mutex_destroy); 147STATIC_LIB_REQUIRE(_pthread_mutex_init); 148STATIC_LIB_REQUIRE(_pthread_mutex_lock); 149STATIC_LIB_REQUIRE(_pthread_mutex_trylock); 150STATIC_LIB_REQUIRE(_pthread_mutex_unlock); 151STATIC_LIB_REQUIRE(_pthread_mutexattr_init); 152STATIC_LIB_REQUIRE(_pthread_mutexattr_destroy); 153STATIC_LIB_REQUIRE(_pthread_mutexattr_settype); 154STATIC_LIB_REQUIRE(_pthread_once); 155STATIC_LIB_REQUIRE(_pthread_setspecific); 156STATIC_LIB_REQUIRE(_raise); 157STATIC_LIB_REQUIRE(_sem_destroy); 158STATIC_LIB_REQUIRE(_sem_getvalue); 159STATIC_LIB_REQUIRE(_sem_init); 160STATIC_LIB_REQUIRE(_sem_post); 161STATIC_LIB_REQUIRE(_sem_timedwait); 162STATIC_LIB_REQUIRE(_sem_trywait); 163STATIC_LIB_REQUIRE(_sem_wait); 164STATIC_LIB_REQUIRE(_sigaction); 165STATIC_LIB_REQUIRE(_sigprocmask); 166STATIC_LIB_REQUIRE(_sigsuspend); 167STATIC_LIB_REQUIRE(_sigtimedwait); 168STATIC_LIB_REQUIRE(_sigwait); 169STATIC_LIB_REQUIRE(_sigwaitinfo); 170STATIC_LIB_REQUIRE(_spinlock); 171STATIC_LIB_REQUIRE(_spinlock_debug); 172STATIC_LIB_REQUIRE(_spinunlock); 173STATIC_LIB_REQUIRE(_thread_init_hack); 174 175/* 176 * These are needed when linking statically. All references within 177 * libgcc (and in the future libc) to these routines are weak, but 178 * if they are not (strongly) referenced by the application or other 179 * libraries, then the actual functions will not be loaded. 180 */ 181STATIC_LIB_REQUIRE(_pthread_once); 182STATIC_LIB_REQUIRE(_pthread_key_create); 183STATIC_LIB_REQUIRE(_pthread_key_delete); 184STATIC_LIB_REQUIRE(_pthread_getspecific); 185STATIC_LIB_REQUIRE(_pthread_setspecific); 186STATIC_LIB_REQUIRE(_pthread_mutex_init); 187STATIC_LIB_REQUIRE(_pthread_mutex_destroy); 188STATIC_LIB_REQUIRE(_pthread_mutex_lock); 189STATIC_LIB_REQUIRE(_pthread_mutex_trylock); 190STATIC_LIB_REQUIRE(_pthread_mutex_unlock); 191STATIC_LIB_REQUIRE(_pthread_create); 192 193/* Pull in all symbols required by libthread_db */ 194STATIC_LIB_REQUIRE(_thread_state_running); 195 196#define DUAL_ENTRY(entry) \ 197 (pthread_func_t)entry, (pthread_func_t)entry 198 199static pthread_func_t jmp_table[][2] = { 200 {DUAL_ENTRY(_pthread_atfork)}, /* PJT_ATFORK */ 201 {DUAL_ENTRY(_pthread_attr_destroy)}, /* PJT_ATTR_DESTROY */ 202 {DUAL_ENTRY(_pthread_attr_getdetachstate)}, /* PJT_ATTR_GETDETACHSTATE */ 203 {DUAL_ENTRY(_pthread_attr_getguardsize)}, /* PJT_ATTR_GETGUARDSIZE */ 204 {DUAL_ENTRY(_pthread_attr_getinheritsched)}, /* PJT_ATTR_GETINHERITSCHED */ 205 {DUAL_ENTRY(_pthread_attr_getschedparam)}, /* PJT_ATTR_GETSCHEDPARAM */ 206 {DUAL_ENTRY(_pthread_attr_getschedpolicy)}, /* PJT_ATTR_GETSCHEDPOLICY */ 207 {DUAL_ENTRY(_pthread_attr_getscope)}, /* PJT_ATTR_GETSCOPE */ 208 {DUAL_ENTRY(_pthread_attr_getstackaddr)}, /* PJT_ATTR_GETSTACKADDR */ 209 {DUAL_ENTRY(_pthread_attr_getstacksize)}, /* PJT_ATTR_GETSTACKSIZE */ 210 {DUAL_ENTRY(_pthread_attr_init)}, /* PJT_ATTR_INIT */ 211 {DUAL_ENTRY(_pthread_attr_setdetachstate)}, /* PJT_ATTR_SETDETACHSTATE */ 212 {DUAL_ENTRY(_pthread_attr_setguardsize)}, /* PJT_ATTR_SETGUARDSIZE */ 213 {DUAL_ENTRY(_pthread_attr_setinheritsched)}, /* PJT_ATTR_SETINHERITSCHED */ 214 {DUAL_ENTRY(_pthread_attr_setschedparam)}, /* PJT_ATTR_SETSCHEDPARAM */ 215 {DUAL_ENTRY(_pthread_attr_setschedpolicy)}, /* PJT_ATTR_SETSCHEDPOLICY */ 216 {DUAL_ENTRY(_pthread_attr_setscope)}, /* PJT_ATTR_SETSCOPE */ 217 {DUAL_ENTRY(_pthread_attr_setstackaddr)}, /* PJT_ATTR_SETSTACKADDR */ 218 {DUAL_ENTRY(_pthread_attr_setstacksize)}, /* PJT_ATTR_SETSTACKSIZE */ 219 {DUAL_ENTRY(_pthread_cancel)}, /* PJT_CANCEL */ 220 {DUAL_ENTRY(_pthread_cleanup_pop)}, /* PJT_CLEANUP_POP */ 221 {DUAL_ENTRY(_pthread_cleanup_push)}, /* PJT_CLEANUP_PUSH */ 222 {DUAL_ENTRY(_pthread_cond_broadcast)}, /* PJT_COND_BROADCAST */ 223 {DUAL_ENTRY(_pthread_cond_destroy)}, /* PJT_COND_DESTROY */ 224 {DUAL_ENTRY(_pthread_cond_init)}, /* PJT_COND_INIT */ 225 {DUAL_ENTRY(_pthread_cond_signal)}, /* PJT_COND_SIGNAL */ 226 {DUAL_ENTRY(_pthread_cond_timedwait)}, /* PJT_COND_TIMEDWAIT */ 227 {(pthread_func_t)__pthread_cond_wait, 228 (pthread_func_t)_pthread_cond_wait}, /* PJT_COND_WAIT */ 229 {DUAL_ENTRY(_pthread_detach)}, /* PJT_DETACH */ 230 {DUAL_ENTRY(_pthread_equal)}, /* PJT_EQUAL */ 231 {DUAL_ENTRY(_pthread_exit)}, /* PJT_EXIT */ 232 {DUAL_ENTRY(_pthread_getspecific)}, /* PJT_GETSPECIFIC */ 233 {DUAL_ENTRY(_pthread_join)}, /* PJT_JOIN */ 234 {DUAL_ENTRY(_pthread_key_create)}, /* PJT_KEY_CREATE */ 235 {DUAL_ENTRY(_pthread_key_delete)}, /* PJT_KEY_DELETE*/ 236 {DUAL_ENTRY(_pthread_kill)}, /* PJT_KILL */ 237 {DUAL_ENTRY(_pthread_main_np)}, /* PJT_MAIN_NP */ 238 {DUAL_ENTRY(_pthread_mutexattr_destroy)}, /* PJT_MUTEXATTR_DESTROY */ 239 {DUAL_ENTRY(_pthread_mutexattr_init)}, /* PJT_MUTEXATTR_INIT */ 240 {DUAL_ENTRY(_pthread_mutexattr_settype)}, /* PJT_MUTEXATTR_SETTYPE */ 241 {DUAL_ENTRY(_pthread_mutex_destroy)}, /* PJT_MUTEX_DESTROY */ 242 {DUAL_ENTRY(_pthread_mutex_init)}, /* PJT_MUTEX_INIT */ 243 {(pthread_func_t)__pthread_mutex_lock, 244 (pthread_func_t)_pthread_mutex_lock}, /* PJT_MUTEX_LOCK */ 245 {(pthread_func_t)__pthread_mutex_trylock, 246 (pthread_func_t)_pthread_mutex_trylock},/* PJT_MUTEX_TRYLOCK */ 247 {DUAL_ENTRY(_pthread_mutex_unlock)}, /* PJT_MUTEX_UNLOCK */ 248 {DUAL_ENTRY(_pthread_once)}, /* PJT_ONCE */ 249 {DUAL_ENTRY(_pthread_rwlock_destroy)}, /* PJT_RWLOCK_DESTROY */ 250 {DUAL_ENTRY(_pthread_rwlock_init)}, /* PJT_RWLOCK_INIT */ 251 {DUAL_ENTRY(_pthread_rwlock_rdlock)}, /* PJT_RWLOCK_RDLOCK */ 252 {DUAL_ENTRY(_pthread_rwlock_tryrdlock)},/* PJT_RWLOCK_TRYRDLOCK */ 253 {DUAL_ENTRY(_pthread_rwlock_trywrlock)},/* PJT_RWLOCK_TRYWRLOCK */ 254 {DUAL_ENTRY(_pthread_rwlock_unlock)}, /* PJT_RWLOCK_UNLOCK */ 255 {DUAL_ENTRY(_pthread_rwlock_wrlock)}, /* PJT_RWLOCK_WRLOCK */ 256 {DUAL_ENTRY(_pthread_self)}, /* PJT_SELF */ 257 {DUAL_ENTRY(_pthread_setcancelstate)}, /* PJT_SETCANCELSTATE */ 258 {DUAL_ENTRY(_pthread_setcanceltype)}, /* PJT_SETCANCELTYPE */ 259 {DUAL_ENTRY(_pthread_setspecific)}, /* PJT_SETSPECIFIC */ 260 {DUAL_ENTRY(_pthread_sigmask)}, /* PJT_SIGMASK */ 261 {DUAL_ENTRY(_pthread_testcancel)}, /* PJT_TESTCANCEL */ 262 {DUAL_ENTRY(__pthread_cleanup_pop_imp)},/* PJT_CLEANUP_POP_IMP */ 263 {DUAL_ENTRY(__pthread_cleanup_push_imp)},/* PJT_CLEANUP_PUSH_IMP */ 264 {DUAL_ENTRY(_pthread_cancel_enter)}, /* PJT_CANCEL_ENTER */ 265 {DUAL_ENTRY(_pthread_cancel_leave)} /* PJT_CANCEL_LEAVE */ 266}; 267 268static int init_once = 0; 269 270/* 271 * For the shared version of the threads library, the above is sufficient. 272 * But for the archive version of the library, we need a little bit more. 273 * Namely, we must arrange for this particular module to be pulled in from 274 * the archive library at link time. To accomplish that, we define and 275 * initialize a variable, "_thread_autoinit_dummy_decl". This variable is 276 * referenced (as an extern) from libc/stdlib/exit.c. This will always 277 * create a need for this module, ensuring that it is present in the 278 * executable. 279 */ 280extern int _thread_autoinit_dummy_decl; 281int _thread_autoinit_dummy_decl = 0; 282 283void 284_thread_init_hack(void) 285{ 286 287 _libpthread_init(NULL); 288} 289 290 291/* 292 * Threaded process initialization. 293 * 294 * This is only called under two conditions: 295 * 296 * 1) Some thread routines have detected that the library hasn't yet 297 * been initialized (_thr_initial == NULL && curthread == NULL), or 298 * 299 * 2) An explicit call to reinitialize after a fork (indicated 300 * by curthread != NULL) 301 */ 302void 303_libpthread_init(struct pthread *curthread) 304{ 305 int first, dlopened; 306 307 /* Check if this function has already been called: */ 308 if ((_thr_initial != NULL) && (curthread == NULL)) 309 /* Only initialize the threaded application once. */ 310 return; 311 312 /* 313 * Check the size of the jump table to make sure it is preset 314 * with the correct number of entries. 315 */ 316 if (sizeof(jmp_table) != (sizeof(pthread_func_t) * PJT_MAX * 2)) 317 PANIC("Thread jump table not properly initialized"); 318 memcpy(__thr_jtable, jmp_table, sizeof(jmp_table)); 319 __thr_interpose_libc(); 320 321 /* Initialize pthread private data. */ 322 init_private(); 323 324 /* Set the initial thread. */ 325 if (curthread == NULL) { 326 first = 1; 327 /* Create and initialize the initial thread. */ 328 curthread = _thr_alloc(NULL); 329 if (curthread == NULL) 330 PANIC("Can't allocate initial thread"); 331 init_main_thread(curthread); 332 } else { 333 first = 0; 334 } 335 336 /* 337 * Add the thread to the thread list queue. 338 */ 339 THR_LIST_ADD(curthread); 340 _thread_active_threads = 1; 341 342 /* Setup the thread specific data */ 343 _tcb_set(curthread->tcb); 344 345 if (first) { 346 _thr_initial = curthread; 347 dlopened = _rtld_is_dlopened(&_thread_autoinit_dummy_decl) != 0; 348 _thr_signal_init(dlopened); 349 if (_thread_event_mask & TD_CREATE) 350 _thr_report_creation(curthread, curthread); 351 /* 352 * Always use our rtld lock implementation. 353 * It is faster because it postpones signal handlers 354 * instead of calling sigprocmask(2). 355 */ 356 _thr_rtld_init(); 357 } 358} 359 360/* 361 * This function and pthread_create() do a lot of the same things. 362 * It'd be nice to consolidate the common stuff in one place. 363 */ 364static void 365init_main_thread(struct pthread *thread) 366{ 367 struct sched_param sched_param; 368 369 /* Setup the thread attributes. */ 370 thr_self(&thread->tid); 371 thread->attr = _pthread_attr_default; 372 /* 373 * Set up the thread stack. 374 * 375 * Create a red zone below the main stack. All other stacks 376 * are constrained to a maximum size by the parameters 377 * passed to mmap(), but this stack is only limited by 378 * resource limits, so this stack needs an explicitly mapped 379 * red zone to protect the thread stack that is just beyond. 380 */ 381 if (mmap(_usrstack - _thr_stack_initial - 382 _thr_guard_default, _thr_guard_default, 0, MAP_ANON, 383 -1, 0) == MAP_FAILED) 384 PANIC("Cannot allocate red zone for initial thread"); 385 386 /* 387 * Mark the stack as an application supplied stack so that it 388 * isn't deallocated. 389 * 390 * XXX - I'm not sure it would hurt anything to deallocate 391 * the main thread stack because deallocation doesn't 392 * actually free() it; it just puts it in the free 393 * stack queue for later reuse. 394 */ 395 thread->attr.stackaddr_attr = _usrstack - _thr_stack_initial; 396 thread->attr.stacksize_attr = _thr_stack_initial; 397 thread->attr.guardsize_attr = _thr_guard_default; 398 thread->attr.flags |= THR_STACK_USER; 399 400 /* 401 * Write a magic value to the thread structure 402 * to help identify valid ones: 403 */ 404 thread->magic = THR_MAGIC; 405 406 thread->cancel_enable = 1; 407 thread->cancel_async = 0; 408 409 /* Initialize the mutex queue: */ 410 TAILQ_INIT(&thread->mutexq); 411 TAILQ_INIT(&thread->pp_mutexq); 412 413 thread->state = PS_RUNNING; 414 415 _thr_getscheduler(thread->tid, &thread->attr.sched_policy, 416 &sched_param); 417 thread->attr.prio = sched_param.sched_priority; 418 419#ifdef _PTHREAD_FORCED_UNWIND 420 thread->unwind_stackend = _usrstack; 421#endif 422 423 /* Others cleared to zero by thr_alloc() */ 424} 425 426static void 427init_private(void) 428{ 429 struct rlimit rlim; 430 size_t len; 431 int mib[2]; 432 char *env, *env_bigstack, *env_splitstack; 433 434 _thr_umutex_init(&_mutex_static_lock); 435 _thr_umutex_init(&_cond_static_lock); 436 _thr_umutex_init(&_rwlock_static_lock); 437 _thr_umutex_init(&_keytable_lock); 438 _thr_urwlock_init(&_thr_atfork_lock); 439 _thr_umutex_init(&_thr_event_lock); 440 _thr_umutex_init(&_suspend_all_lock); 441 _thr_once_init(); 442 _thr_spinlock_init(); 443 _thr_list_init(); 444 _thr_wake_addr_init(); 445 _sleepq_init(); 446 _single_thread = NULL; 447 _suspend_all_waiters = 0; 448 449 /* 450 * Avoid reinitializing some things if they don't need to be, 451 * e.g. after a fork(). 452 */ 453 if (init_once == 0) { 454 /* Find the stack top */ 455 mib[0] = CTL_KERN; 456 mib[1] = KERN_USRSTACK; 457 len = sizeof (_usrstack); 458 if (sysctl(mib, 2, &_usrstack, &len, NULL, 0) == -1) 459 PANIC("Cannot get kern.usrstack from sysctl"); 460 env_bigstack = getenv("LIBPTHREAD_BIGSTACK_MAIN"); 461 env_splitstack = getenv("LIBPTHREAD_SPLITSTACK_MAIN"); 462 if (env_bigstack != NULL || env_splitstack == NULL) { 463 if (getrlimit(RLIMIT_STACK, &rlim) == -1) 464 PANIC("Cannot get stack rlimit"); 465 _thr_stack_initial = rlim.rlim_cur; 466 } 467 len = sizeof(_thr_is_smp); 468 sysctlbyname("kern.smp.cpus", &_thr_is_smp, &len, NULL, 0); 469 _thr_is_smp = (_thr_is_smp > 1); 470 _thr_page_size = getpagesize(); 471 _thr_guard_default = _thr_page_size; 472 _pthread_attr_default.guardsize_attr = _thr_guard_default; 473 _pthread_attr_default.stacksize_attr = _thr_stack_default; 474 env = getenv("LIBPTHREAD_SPINLOOPS"); 475 if (env) 476 _thr_spinloops = atoi(env); 477 env = getenv("LIBPTHREAD_YIELDLOOPS"); 478 if (env) 479 _thr_yieldloops = atoi(env); 480 env = getenv("LIBPTHREAD_QUEUE_FIFO"); 481 if (env) 482 _thr_queuefifo = atoi(env); 483 TAILQ_INIT(&_thr_atfork_list); 484 } 485 init_once = 1; 486} 487