lib/libthr/thread/thr_init.c

   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 }