lib/libthr/thread/thr_init.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-4-Clause
   3  *
   4  * Copyright (c) 2003 Daniel M. Eischen <deischen@freebsd.org>
   5  * Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>
   6  * All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. All advertising materials mentioning features or use of this software
  17  *    must display the following acknowledgement:
  18  *      This product includes software developed by John Birrell.
  19  * 4. Neither the name of the author nor the names of any co-contributors
  20  *    may be used to endorse or promote products derived from this software
  21  *    without specific prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
  24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  */
  35
  36 #include <sys/cdefs.h>
  37 __FBSDID("$FreeBSD$");
  38
  39 #include "namespace.h"
  40 #include <sys/param.h>
  41 #include <sys/auxv.h>
  42 #include <sys/signalvar.h>
  43 #include <sys/ioctl.h>
  44 #include <sys/link_elf.h>
  45 #include <sys/resource.h>
  46 #include <sys/sysctl.h>
  47 #include <sys/ttycom.h>
  48 #include <sys/mman.h>
  49 #include <sys/rtprio.h>
  50 #include <errno.h>
  51 #include <fcntl.h>
  52 #include <paths.h>
  53 #include <pthread.h>
  54 #include <pthread_np.h>
  55 #include <signal.h>
  56 #include <stdlib.h>
  57 #include <string.h>
  58 #include <time.h>
  59 #include <unistd.h>
  60 #include "un-namespace.h"
  61
  62 #include "libc_private.h"
  63 #include "thr_private.h"
  64
  65 char            *_usrstack;
  66 struct pthread  *_thr_initial;
  67 int             _libthr_debug;
  68 int             _thread_event_mask;
  69 struct pthread  *_thread_last_event;
  70 pthreadlist     _thread_list = TAILQ_HEAD_INITIALIZER(_thread_list);
  71 pthreadlist     _thread_gc_list = TAILQ_HEAD_INITIALIZER(_thread_gc_list);
  72 int             _thread_active_threads = 1;
  73 atfork_head     _thr_atfork_list = TAILQ_HEAD_INITIALIZER(_thr_atfork_list);
  74 struct urwlock  _thr_atfork_lock = DEFAULT_URWLOCK;
  75
  76 struct pthread_prio     _thr_priorities[3] = {
  77         {RTP_PRIO_MIN,  RTP_PRIO_MAX, 0}, /* FIFO */
  78         {0, 0, 63}, /* OTHER */
  79         {RTP_PRIO_MIN, RTP_PRIO_MAX, 0}  /* RR */
  80 };
  81
  82 struct pthread_attr _pthread_attr_default = {
  83         .sched_policy = SCHED_OTHER,
  84         .sched_inherit = PTHREAD_INHERIT_SCHED,
  85         .prio = 0,
  86         .suspend = THR_CREATE_RUNNING,
  87         .flags = PTHREAD_SCOPE_SYSTEM,
  88         .stackaddr_attr = NULL,
  89         .stacksize_attr = THR_STACK_DEFAULT,
  90         .guardsize_attr = 0,
  91         .cpusetsize = 0,
  92         .cpuset = NULL
  93 };
  94
  95 struct pthread_mutex_attr _pthread_mutexattr_default = {
  96         .m_type = PTHREAD_MUTEX_DEFAULT,
  97         .m_protocol = PTHREAD_PRIO_NONE,
  98         .m_ceiling = 0,
  99         .m_pshared = PTHREAD_PROCESS_PRIVATE,
 100         .m_robust = PTHREAD_MUTEX_STALLED,
 101 };
 102
 103 struct pthread_mutex_attr _pthread_mutexattr_adaptive_default = {
 104         .m_type = PTHREAD_MUTEX_ADAPTIVE_NP,
 105         .m_protocol = PTHREAD_PRIO_NONE,
 106         .m_ceiling = 0,
 107         .m_pshared = PTHREAD_PROCESS_PRIVATE,
 108         .m_robust = PTHREAD_MUTEX_STALLED,
 109 };
 110
 111 /* Default condition variable attributes: */
 112 struct pthread_cond_attr _pthread_condattr_default = {
 113         .c_pshared = PTHREAD_PROCESS_PRIVATE,
 114         .c_clockid = CLOCK_REALTIME
 115 };
 116
 117 int             _thr_is_smp = 0;
 118 size_t          _thr_guard_default;
 119 size_t          _thr_stack_default = THR_STACK_DEFAULT;
 120 size_t          _thr_stack_initial = THR_STACK_INITIAL;
 121 int             _thr_page_size;
 122 int             _thr_spinloops;
 123 int             _thr_yieldloops;
 124 int             _thr_queuefifo = 4;
 125 int             _gc_count;
 126 struct umutex   _mutex_static_lock = DEFAULT_UMUTEX;
 127 struct umutex   _cond_static_lock = DEFAULT_UMUTEX;
 128 struct umutex   _rwlock_static_lock = DEFAULT_UMUTEX;
 129 struct umutex   _keytable_lock = DEFAULT_UMUTEX;
 130 struct urwlock  _thr_list_lock = DEFAULT_URWLOCK;
 131 struct umutex   _thr_event_lock = DEFAULT_UMUTEX;
 132 struct umutex   _suspend_all_lock = DEFAULT_UMUTEX;
 133 struct pthread  *_single_thread;
 134 int             _suspend_all_cycle;
 135 int             _suspend_all_waiters;
 136
 137 int     __pthread_cond_wait(pthread_cond_t *, pthread_mutex_t *);
 138 int     __pthread_mutex_lock(pthread_mutex_t *);
 139 int     __pthread_mutex_trylock(pthread_mutex_t *);
 140 void    _thread_init_hack(void) __attribute__ ((constructor));
 141
 142 static void init_private(void);
 143 static void init_main_thread(struct pthread *thread);
 144
 145 /*
 146  * All weak references used within libc should be in this table.
 147  * This is so that static libraries will work.
 148  */
 149
 150 STATIC_LIB_REQUIRE(_fork);
 151 STATIC_LIB_REQUIRE(_pthread_getspecific);
 152 STATIC_LIB_REQUIRE(_pthread_key_create);
 153 STATIC_LIB_REQUIRE(_pthread_key_delete);
 154 STATIC_LIB_REQUIRE(_pthread_mutex_destroy);
 155 STATIC_LIB_REQUIRE(_pthread_mutex_init);
 156 STATIC_LIB_REQUIRE(_pthread_mutex_lock);
 157 STATIC_LIB_REQUIRE(_pthread_mutex_trylock);
 158 STATIC_LIB_REQUIRE(_pthread_mutex_unlock);
 159 STATIC_LIB_REQUIRE(_pthread_mutexattr_init);
 160 STATIC_LIB_REQUIRE(_pthread_mutexattr_destroy);
 161 STATIC_LIB_REQUIRE(_pthread_mutexattr_settype);
 162 STATIC_LIB_REQUIRE(_pthread_once);
 163 STATIC_LIB_REQUIRE(_pthread_setspecific);
 164 STATIC_LIB_REQUIRE(_raise);
 165 STATIC_LIB_REQUIRE(_sem_destroy);
 166 STATIC_LIB_REQUIRE(_sem_getvalue);
 167 STATIC_LIB_REQUIRE(_sem_init);
 168 STATIC_LIB_REQUIRE(_sem_post);
 169 STATIC_LIB_REQUIRE(_sem_timedwait);
 170 STATIC_LIB_REQUIRE(_sem_trywait);
 171 STATIC_LIB_REQUIRE(_sem_wait);
 172 STATIC_LIB_REQUIRE(_sigaction);
 173 STATIC_LIB_REQUIRE(_sigprocmask);
 174 STATIC_LIB_REQUIRE(_sigsuspend);
 175 STATIC_LIB_REQUIRE(_sigtimedwait);
 176 STATIC_LIB_REQUIRE(_sigwait);
 177 STATIC_LIB_REQUIRE(_sigwaitinfo);
 178 STATIC_LIB_REQUIRE(_spinlock);
 179 STATIC_LIB_REQUIRE(_spinunlock);
 180 STATIC_LIB_REQUIRE(_thread_init_hack);
 181
 182 /*
 183  * These are needed when linking statically.  All references within
 184  * libgcc (and in the future libc) to these routines are weak, but
 185  * if they are not (strongly) referenced by the application or other
 186  * libraries, then the actual functions will not be loaded.
 187  */
 188 STATIC_LIB_REQUIRE(_pthread_once);
 189 STATIC_LIB_REQUIRE(_pthread_key_create);
 190 STATIC_LIB_REQUIRE(_pthread_key_delete);
 191 STATIC_LIB_REQUIRE(_pthread_getspecific);
 192 STATIC_LIB_REQUIRE(_pthread_setspecific);
 193 STATIC_LIB_REQUIRE(_pthread_mutex_init);
 194 STATIC_LIB_REQUIRE(_pthread_mutex_destroy);
 195 STATIC_LIB_REQUIRE(_pthread_mutex_lock);
 196 STATIC_LIB_REQUIRE(_pthread_mutex_trylock);
 197 STATIC_LIB_REQUIRE(_pthread_mutex_unlock);
 198 STATIC_LIB_REQUIRE(_pthread_create);
 199
 200 /* Pull in all symbols required by libthread_db */
 201 STATIC_LIB_REQUIRE(_thread_state_running);
 202
 203 #define DUAL_ENTRY(entry)       \
 204         (pthread_func_t)entry, (pthread_func_t)entry
 205
 206 static pthread_func_t jmp_table[][2] = {
 207         [PJT_ATFORK] = {DUAL_ENTRY(_thr_atfork)},
 208         [PJT_ATTR_DESTROY] = {DUAL_ENTRY(_thr_attr_destroy)},
 209         [PJT_ATTR_GETDETACHSTATE] = {DUAL_ENTRY(_thr_attr_getdetachstate)},
 210         [PJT_ATTR_GETGUARDSIZE] = {DUAL_ENTRY(_thr_attr_getguardsize)},
 211         [PJT_ATTR_GETINHERITSCHED] = {DUAL_ENTRY(_thr_attr_getinheritsched)},
 212         [PJT_ATTR_GETSCHEDPARAM] = {DUAL_ENTRY(_thr_attr_getschedparam)},
 213         [PJT_ATTR_GETSCHEDPOLICY] = {DUAL_ENTRY(_thr_attr_getschedpolicy)},
 214         [PJT_ATTR_GETSCOPE] = {DUAL_ENTRY(_thr_attr_getscope)},
 215         [PJT_ATTR_GETSTACKADDR] = {DUAL_ENTRY(_thr_attr_getstackaddr)},
 216         [PJT_ATTR_GETSTACKSIZE] = {DUAL_ENTRY(_thr_attr_getstacksize)},
 217         [PJT_ATTR_INIT] = {DUAL_ENTRY(_thr_attr_init)},
 218         [PJT_ATTR_SETDETACHSTATE] = {DUAL_ENTRY(_thr_attr_setdetachstate)},
 219         [PJT_ATTR_SETGUARDSIZE] = {DUAL_ENTRY(_thr_attr_setguardsize)},
 220         [PJT_ATTR_SETINHERITSCHED] = {DUAL_ENTRY(_thr_attr_setinheritsched)},
 221         [PJT_ATTR_SETSCHEDPARAM] = {DUAL_ENTRY(_thr_attr_setschedparam)},
 222         [PJT_ATTR_SETSCHEDPOLICY] = {DUAL_ENTRY(_thr_attr_setschedpolicy)},
 223         [PJT_ATTR_SETSCOPE] = {DUAL_ENTRY(_thr_attr_setscope)},
 224         [PJT_ATTR_SETSTACKADDR] = {DUAL_ENTRY(_thr_attr_setstackaddr)},
 225         [PJT_ATTR_SETSTACKSIZE] = {DUAL_ENTRY(_thr_attr_setstacksize)},
 226         [PJT_CANCEL] = {DUAL_ENTRY(_thr_cancel)},
 227         [PJT_CLEANUP_POP] = {DUAL_ENTRY(_thr_cleanup_pop)},
 228         [PJT_CLEANUP_PUSH] = {DUAL_ENTRY(_thr_cleanup_push)},
 229         [PJT_COND_BROADCAST] = {DUAL_ENTRY(_thr_cond_broadcast)},
 230         [PJT_COND_DESTROY] = {DUAL_ENTRY(_thr_cond_destroy)},
 231         [PJT_COND_INIT] = {DUAL_ENTRY(_thr_cond_init)},
 232         [PJT_COND_SIGNAL] = {DUAL_ENTRY(_thr_cond_signal)},
 233         [PJT_COND_TIMEDWAIT] = {DUAL_ENTRY(_thr_cond_timedwait)},
 234         [PJT_COND_WAIT] = {(pthread_func_t)__thr_cond_wait,
 235             (pthread_func_t)_thr_cond_wait},
 236         [PJT_DETACH] = {DUAL_ENTRY(_thr_detach)},
 237         [PJT_EQUAL] = {DUAL_ENTRY(_thr_equal)},
 238         [PJT_EXIT] = {DUAL_ENTRY(_Tthr_exit)},
 239         [PJT_GETSPECIFIC] = {DUAL_ENTRY(_thr_getspecific)},
 240         [PJT_JOIN] = {DUAL_ENTRY(_thr_join)},
 241         [PJT_KEY_CREATE] = {DUAL_ENTRY(_thr_key_create)},
 242         [PJT_KEY_DELETE] = {DUAL_ENTRY(_thr_key_delete)},
 243         [PJT_KILL] = {DUAL_ENTRY(_Tthr_kill)},
 244         [PJT_MAIN_NP] = {DUAL_ENTRY(_thr_main_np)},
 245         [PJT_MUTEXATTR_DESTROY] = {DUAL_ENTRY(_thr_mutexattr_destroy)},
 246         [PJT_MUTEXATTR_INIT] = {DUAL_ENTRY(_thr_mutexattr_init)},
 247         [PJT_MUTEXATTR_SETTYPE] = {DUAL_ENTRY(_thr_mutexattr_settype)},
 248         [PJT_MUTEX_DESTROY] = {DUAL_ENTRY(_thr_mutex_destroy)},
 249         [PJT_MUTEX_INIT] = {DUAL_ENTRY(__Tthr_mutex_init)},
 250         [PJT_MUTEX_LOCK] = {DUAL_ENTRY(__Tthr_mutex_lock)},
 251         [PJT_MUTEX_TRYLOCK] = {DUAL_ENTRY(__Tthr_mutex_trylock)},
 252         [PJT_MUTEX_UNLOCK] = {DUAL_ENTRY(_thr_mutex_unlock)},
 253         [PJT_ONCE] = {DUAL_ENTRY(_thr_once)},
 254         [PJT_RWLOCK_DESTROY] = {DUAL_ENTRY(_thr_rwlock_destroy)},
 255         [PJT_RWLOCK_INIT] = {DUAL_ENTRY(_thr_rwlock_init)},
 256         [PJT_RWLOCK_RDLOCK] = {DUAL_ENTRY(_Tthr_rwlock_rdlock)},
 257         [PJT_RWLOCK_TRYRDLOCK] = {DUAL_ENTRY(_Tthr_rwlock_tryrdlock)},
 258         [PJT_RWLOCK_TRYWRLOCK] = {DUAL_ENTRY(_Tthr_rwlock_trywrlock)},
 259         [PJT_RWLOCK_UNLOCK] = {DUAL_ENTRY(_Tthr_rwlock_unlock)},
 260         [PJT_RWLOCK_WRLOCK] = {DUAL_ENTRY(_Tthr_rwlock_wrlock)},
 261         [PJT_SELF] = {DUAL_ENTRY(_Tthr_self)},
 262         [PJT_SETCANCELSTATE] = {DUAL_ENTRY(_thr_setcancelstate)},
 263         [PJT_SETCANCELTYPE] = {DUAL_ENTRY(_thr_setcanceltype)},
 264         [PJT_SETSPECIFIC] = {DUAL_ENTRY(_thr_setspecific)},
 265         [PJT_SIGMASK] = {DUAL_ENTRY(_thr_sigmask)},
 266         [PJT_TESTCANCEL] = {DUAL_ENTRY(_Tthr_testcancel)},
 267         [PJT_CLEANUP_POP_IMP] = {DUAL_ENTRY(__thr_cleanup_pop_imp)},
 268         [PJT_CLEANUP_PUSH_IMP] = {DUAL_ENTRY(__thr_cleanup_push_imp)},
 269         [PJT_CANCEL_ENTER] = {DUAL_ENTRY(_Tthr_cancel_enter)},
 270         [PJT_CANCEL_LEAVE] = {DUAL_ENTRY(_Tthr_cancel_leave)},
 271         [PJT_MUTEX_CONSISTENT] = {DUAL_ENTRY(_Tthr_mutex_consistent)},
 272         [PJT_MUTEXATTR_GETROBUST] = {DUAL_ENTRY(_thr_mutexattr_getrobust)},
 273         [PJT_MUTEXATTR_SETROBUST] = {DUAL_ENTRY(_thr_mutexattr_setrobust)},
 274         [PJT_GETTHREADID_NP] = {DUAL_ENTRY(_thr_getthreadid_np)},
 275         [PJT_ATTR_GET_NP] = {DUAL_ENTRY(_thr_attr_get_np)},
 276 };
 277
 278 static int init_once = 0;
 279
 280 /*
 281  * For the shared version of the threads library, the above is sufficient.
 282  * But for the archive version of the library, we need a little bit more.
 283  * Namely, we must arrange for this particular module to be pulled in from
 284  * the archive library at link time.  To accomplish that, we define and
 285  * initialize a variable, "_thread_autoinit_dummy_decl".  This variable is
 286  * referenced (as an extern) from libc/stdlib/exit.c. This will always
 287  * create a need for this module, ensuring that it is present in the
 288  * executable.
 289  */
 290 extern int _thread_autoinit_dummy_decl;
 291 int _thread_autoinit_dummy_decl = 0;
 292
 293 void
 294 _thread_init_hack(void)
 295 {
 296
 297         _libpthread_init(NULL);
 298 }
 299
 300
 301 /*
 302  * Threaded process initialization.
 303  *
 304  * This is only called under two conditions:
 305  *
 306  *   1) Some thread routines have detected that the library hasn't yet
 307  *      been initialized (_thr_initial == NULL && curthread == NULL), or
 308  *
 309  *   2) An explicit call to reinitialize after a fork (indicated
 310  *      by curthread != NULL)
 311  */
 312 void
 313 _libpthread_init(struct pthread *curthread)
 314 {
 315         int first, dlopened;
 316
 317         /* Check if this function has already been called: */
 318         if (_thr_initial != NULL && curthread == NULL)
 319                 /* Only initialize the threaded application once. */
 320                 return;
 321
 322         /*
 323          * Check the size of the jump table to make sure it is preset
 324          * with the correct number of entries.
 325          */
 326         if (sizeof(jmp_table) != sizeof(pthread_func_t) * PJT_MAX * 2)
 327                 PANIC("Thread jump table not properly initialized");
 328         memcpy(__thr_jtable, jmp_table, sizeof(jmp_table));
 329         __thr_interpose_libc();
 330
 331         /* Initialize pthread private data. */
 332         init_private();
 333
 334         /* Set the initial thread. */
 335         if (curthread == NULL) {
 336                 first = 1;
 337                 /* Create and initialize the initial thread. */
 338                 curthread = _thr_alloc(NULL);
 339                 if (curthread == NULL)
 340                         PANIC("Can't allocate initial thread");
 341                 init_main_thread(curthread);
 342         } else {
 343                 first = 0;
 344         }
 345
 346         /*
 347          * Add the thread to the thread list queue.
 348          */
 349         THR_LIST_ADD(curthread);
 350         _thread_active_threads = 1;
 351
 352         /* Setup the thread specific data */
 353         _tcb_set(curthread->tcb);
 354
 355         if (first) {
 356                 _thr_initial = curthread;
 357                 dlopened = _rtld_is_dlopened(&_thread_autoinit_dummy_decl) != 0;
 358                 _thr_signal_init(dlopened);
 359                 if (_thread_event_mask & TD_CREATE)
 360                         _thr_report_creation(curthread, curthread);
 361                 /*
 362                  * Always use our rtld lock implementation.
 363                  * It is faster because it postpones signal handlers
 364                  * instead of calling sigprocmask(2).
 365                  */
 366                 _thr_rtld_init();
 367         }
 368 }
 369
 370 /*
 371  * This function and pthread_create() do a lot of the same things.
 372  * It'd be nice to consolidate the common stuff in one place.
 373  */
 374 static void
 375 init_main_thread(struct pthread *thread)
 376 {
 377         struct sched_param sched_param;
 378         int i;
 379
 380         /* Setup the thread attributes. */
 381         thr_self(&thread->tid);
 382         thread->attr = _pthread_attr_default;
 383         /*
 384          * Set up the thread stack.
 385          *
 386          * Create a red zone below the main stack.  All other stacks
 387          * are constrained to a maximum size by the parameters
 388          * passed to mmap(), but this stack is only limited by
 389          * resource limits, so this stack needs an explicitly mapped
 390          * red zone to protect the thread stack that is just beyond.
 391          */
 392         if (mmap(_usrstack - _thr_stack_initial -
 393             _thr_guard_default, _thr_guard_default, 0, MAP_ANON,
 394             -1, 0) == MAP_FAILED)
 395                 PANIC("Cannot allocate red zone for initial thread");
 396
 397         /*
 398          * Mark the stack as an application supplied stack so that it
 399          * isn't deallocated.
 400          *
 401          * XXX - I'm not sure it would hurt anything to deallocate
 402          *       the main thread stack because deallocation doesn't
 403          *       actually free() it; it just puts it in the free
 404          *       stack queue for later reuse.
 405          */
 406         thread->attr.stackaddr_attr = _usrstack - _thr_stack_initial;
 407         thread->attr.stacksize_attr = _thr_stack_initial;
 408         thread->attr.guardsize_attr = _thr_guard_default;
 409         thread->attr.flags |= THR_STACK_USER;
 410
 411         /*
 412          * Write a magic value to the thread structure
 413          * to help identify valid ones:
 414          */
 415         thread->magic = THR_MAGIC;
 416
 417         thread->cancel_enable = 1;
 418         thread->cancel_async = 0;
 419
 420         /* Initialize the mutex queues */
 421         for (i = 0; i < TMQ_NITEMS; i++)
 422                 TAILQ_INIT(&thread->mq[i]);
 423
 424         thread->state = PS_RUNNING;
 425
 426         _thr_getscheduler(thread->tid, &thread->attr.sched_policy,
 427                  &sched_param);
 428         thread->attr.prio = sched_param.sched_priority;
 429
 430 #ifdef _PTHREAD_FORCED_UNWIND
 431         thread->unwind_stackend = _usrstack;
 432 #endif
 433
 434         /* Others cleared to zero by thr_alloc() */
 435 }
 436
 437 static void
 438 init_private(void)
 439 {
 440         struct rlimit rlim;
 441         size_t len;
 442         int mib[2];
 443         char *env, *env_bigstack, *env_splitstack;
 444
 445         _thr_umutex_init(&_mutex_static_lock);
 446         _thr_umutex_init(&_cond_static_lock);
 447         _thr_umutex_init(&_rwlock_static_lock);
 448         _thr_umutex_init(&_keytable_lock);
 449         _thr_urwlock_init(&_thr_atfork_lock);
 450         _thr_umutex_init(&_thr_event_lock);
 451         _thr_umutex_init(&_suspend_all_lock);
 452         _thr_spinlock_init();
 453         _thr_list_init();
 454         _thr_wake_addr_init();
 455         _sleepq_init();
 456         _single_thread = NULL;
 457         _suspend_all_waiters = 0;
 458
 459         /*
 460          * Avoid reinitializing some things if they don't need to be,
 461          * e.g. after a fork().
 462          */
 463         if (init_once == 0) {
 464                 __thr_pshared_init();
 465                 __thr_malloc_init();
 466
 467                 /* Find the stack top */
 468                 if (elf_aux_info(AT_USRSTACKBASE, &_usrstack,
 469                     sizeof(_usrstack)) != 0) {
 470                         mib[0] = CTL_KERN;
 471                         mib[1] = KERN_USRSTACK;
 472                         len = sizeof (_usrstack);
 473                         if (sysctl(mib, nitems(mib), &_usrstack, &len,
 474                             NULL, 0) == -1)
 475                                 PANIC("Cannot get kern.usrstack from sysctl");
 476                 }
 477                 env_bigstack = getenv("LIBPTHREAD_BIGSTACK_MAIN");
 478                 env_splitstack = getenv("LIBPTHREAD_SPLITSTACK_MAIN");
 479                 if (env_bigstack != NULL || env_splitstack == NULL) {
 480                         if (elf_aux_info(AT_USRSTACKLIM, &_thr_stack_initial,
 481                             sizeof(_thr_stack_initial)) != 0) {
 482                                 if (getrlimit(RLIMIT_STACK, &rlim) == -1)
 483                                         PANIC("Cannot get stack rlimit");
 484                                 _thr_stack_initial = rlim.rlim_cur;
 485                         }
 486                 }
 487                 _thr_is_smp = sysconf(_SC_NPROCESSORS_CONF);
 488                 if (_thr_is_smp == -1)
 489                         PANIC("Cannot get _SC_NPROCESSORS_CONF");
 490                 _thr_is_smp = (_thr_is_smp > 1);
 491                 _thr_page_size = getpagesize();
 492                 _thr_guard_default = _thr_page_size;
 493                 _pthread_attr_default.guardsize_attr = _thr_guard_default;
 494                 _pthread_attr_default.stacksize_attr = _thr_stack_default;
 495                 env = getenv("LIBPTHREAD_SPINLOOPS");
 496                 if (env)
 497                         _thr_spinloops = atoi(env);
 498                 env = getenv("LIBPTHREAD_YIELDLOOPS");
 499                 if (env)
 500                         _thr_yieldloops = atoi(env);
 501                 env = getenv("LIBPTHREAD_QUEUE_FIFO");
 502                 if (env)
 503                         _thr_queuefifo = atoi(env);
 504                 TAILQ_INIT(&_thr_atfork_list);
 505         }
 506         init_once = 1;
 507 }