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