1 /* $NetBSD: pthread.c,v 1.110 2009/05/17 14:49:00 ad Exp $ */ 2 3 /*- 4 * Copyright (c) 2001, 2002, 2003, 2006, 2007, 2008 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Nathan J. Williams and Andrew Doran. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 #include <sys/cdefs.h> 33 __RCSID("$NetBSD: pthread.c,v 1.110 2009/05/17 14:49:00 ad Exp $"); 34 35 #define __EXPOSE_STACK 1 36 37 #include <sys/param.h> 38 #include <sys/mman.h> 39 #include <sys/sysctl.h> 40 #include <sys/lwpctl.h> 41 42 #include <err.h> 43 #include <errno.h> 44 #include <lwp.h> 45 #include <signal.h> 46 #include <stdio.h> 47 #include <stdlib.h> 48 #include <string.h> 49 #include <syslog.h> 50 #include <ucontext.h> 51 #include <unistd.h> 52 #include <sched.h> 53 54 #include "pthread.h" 55 #include "pthread_int.h" 56 57 pthread_rwlock_t pthread__alltree_lock = PTHREAD_RWLOCK_INITIALIZER; 58 RB_HEAD(__pthread__alltree, __pthread_st) pthread__alltree; 59 60 #ifndef lint 61 static int pthread__cmp(struct __pthread_st *, struct __pthread_st *); 62 RB_PROTOTYPE_STATIC(__pthread__alltree, __pthread_st, pt_alltree, pthread__cmp) 63 #endif 64 65 static void pthread__create_tramp(void *); 66 static void pthread__initthread(pthread_t); 67 static void pthread__scrubthread(pthread_t, char *, int); 68 static int pthread__stackid_setup(void *, size_t, pthread_t *); 69 static int pthread__stackalloc(pthread_t *); 70 static void pthread__initmain(pthread_t *); 71 static void pthread__fork_callback(void); 72 static void pthread__reap(pthread_t); 73 static void pthread__child_callback(void); 74 static void pthread__start(void); 75 76 void pthread__init(void); 77 78 int pthread__started; 79 pthread_mutex_t pthread__deadqueue_lock = PTHREAD_MUTEX_INITIALIZER; 80 pthread_queue_t pthread__deadqueue; 81 pthread_queue_t pthread__allqueue; 82 83 static pthread_attr_t pthread_default_attr; 84 static lwpctl_t pthread__dummy_lwpctl = { .lc_curcpu = LWPCTL_CPU_NONE }; 85 static pthread_t pthread__first; 86 87 enum { 88 DIAGASSERT_ABORT = 1<<0, 89 DIAGASSERT_STDERR = 1<<1, 90 DIAGASSERT_SYSLOG = 1<<2 91 }; 92 93 static int pthread__diagassert; 94 95 int pthread__concurrency; 96 int pthread__nspins; 97 int pthread__unpark_max = PTHREAD__UNPARK_MAX; 98 99 /* 100 * We have to initialize the pthread_stack* variables here because 101 * mutexes are used before pthread_init() and thus pthread__initmain() 102 * are called. Since mutexes only save the stack pointer and not a 103 * pointer to the thread data, it is safe to change the mapping from 104 * stack pointer to thread data afterwards. 105 */ 106 #define _STACKSIZE_LG 18 107 int pthread__stacksize_lg = _STACKSIZE_LG; 108 size_t pthread__stacksize = 1 << _STACKSIZE_LG; 109 vaddr_t pthread__stackmask = (1 << _STACKSIZE_LG) - 1; 110 vaddr_t pthread__threadmask = (vaddr_t)~((1 << _STACKSIZE_LG) - 1); 111 #undef _STACKSIZE_LG 112 113 int _sys___sigprocmask14(int, const sigset_t *, sigset_t *); 114 115 __strong_alias(__libc_thr_self,pthread_self) 116 __strong_alias(__libc_thr_create,pthread_create) 117 __strong_alias(__libc_thr_exit,pthread_exit) 118 __strong_alias(__libc_thr_errno,pthread__errno) 119 __strong_alias(__libc_thr_setcancelstate,pthread_setcancelstate) 120 __strong_alias(__libc_thr_equal,pthread_equal) 121 __strong_alias(__libc_thr_init,pthread__init) 122 123 /* 124 * Static library kludge. Place a reference to a symbol any library 125 * file which does not already have a reference here. 126 */ 127 extern int pthread__cancel_stub_binder; 128 129 void *pthread__static_lib_binder[] = { 130 &pthread__cancel_stub_binder, 131 pthread_cond_init, 132 pthread_mutex_init, 133 pthread_rwlock_init, 134 pthread_barrier_init, 135 pthread_key_create, 136 pthread_setspecific, 137 }; 138 139 #define NHASHLOCK 64 140 141 static union hashlock { 142 pthread_mutex_t mutex; 143 char pad[64]; 144 } hashlocks[NHASHLOCK] __aligned(64); 145 146 /* 147 * This needs to be started by the library loading code, before main() 148 * gets to run, for various things that use the state of the initial thread 149 * to work properly (thread-specific data is an application-visible example; 150 * spinlock counts for mutexes is an internal example). 151 */ 152 void 153 pthread__init(void) 154 { 155 pthread_t first; 156 char *p; 157 int i, mib[2]; 158 size_t len; 159 extern int __isthreaded; 160 161 mib[0] = CTL_HW; 162 mib[1] = HW_NCPU; 163 164 len = sizeof(pthread__concurrency); 165 if (sysctl(mib, 2, &pthread__concurrency, &len, NULL, 0) == -1) 166 err(1, "sysctl(hw.ncpu"); 167 168 mib[0] = CTL_KERN; 169 mib[1] = KERN_OSREV; 170 171 /* Initialize locks first; they're needed elsewhere. */ 172 pthread__lockprim_init(); 173 for (i = 0; i < NHASHLOCK; i++) { 174 pthread_mutex_init(&hashlocks[i].mutex, NULL); 175 } 176 177 /* Fetch parameters. */ 178 i = (int)_lwp_unpark_all(NULL, 0, NULL); 179 if (i == -1) 180 err(1, "_lwp_unpark_all"); 181 if (i < pthread__unpark_max) 182 pthread__unpark_max = i; 183 184 /* Basic data structure setup */ 185 pthread_attr_init(&pthread_default_attr); 186 PTQ_INIT(&pthread__allqueue); 187 PTQ_INIT(&pthread__deadqueue); 188 RB_INIT(&pthread__alltree); 189 190 /* Create the thread structure corresponding to main() */ 191 pthread__initmain(&first); 192 pthread__initthread(first); 193 pthread__scrubthread(first, NULL, 0); 194 195 first->pt_lid = _lwp_self(); 196 PTQ_INSERT_HEAD(&pthread__allqueue, first, pt_allq); 197 RB_INSERT(__pthread__alltree, &pthread__alltree, first); 198 199 if (_lwp_ctl(LWPCTL_FEATURE_CURCPU, &first->pt_lwpctl) != 0) { 200 err(1, "_lwp_ctl"); 201 } 202 203 /* Start subsystems */ 204 PTHREAD_MD_INIT 205 206 for (p = pthread__getenv("PTHREAD_DIAGASSERT"); p && *p; p++) { 207 switch (*p) { 208 case 'a': 209 pthread__diagassert |= DIAGASSERT_ABORT; 210 break; 211 case 'A': 212 pthread__diagassert &= ~DIAGASSERT_ABORT; 213 break; 214 case 'e': 215 pthread__diagassert |= DIAGASSERT_STDERR; 216 break; 217 case 'E': 218 pthread__diagassert &= ~DIAGASSERT_STDERR; 219 break; 220 case 'l': 221 pthread__diagassert |= DIAGASSERT_SYSLOG; 222 break; 223 case 'L': 224 pthread__diagassert &= ~DIAGASSERT_SYSLOG; 225 break; 226 } 227 } 228 229 /* Tell libc that we're here and it should role-play accordingly. */ 230 pthread__first = first; 231 pthread_atfork(NULL, NULL, pthread__fork_callback); 232 __isthreaded = 1; 233 } 234 235 static void 236 pthread__fork_callback(void) 237 { 238 239 /* lwpctl state is not copied across fork. */ 240 if (_lwp_ctl(LWPCTL_FEATURE_CURCPU, &pthread__first->pt_lwpctl)) { 241 err(1, "_lwp_ctl"); 242 } 243 } 244 245 static void 246 pthread__child_callback(void) 247 { 248 249 /* 250 * Clean up data structures that a forked child process might 251 * trip over. Note that if threads have been created (causing 252 * this handler to be registered) the standards say that the 253 * child will trigger undefined behavior if it makes any 254 * pthread_* calls (or any other calls that aren't 255 * async-signal-safe), so we don't really have to clean up 256 * much. Anything that permits some pthread_* calls to work is 257 * merely being polite. 258 */ 259 pthread__started = 0; 260 } 261 262 static void 263 pthread__start(void) 264 { 265 266 /* 267 * Per-process timers are cleared by fork(); despite the 268 * various restrictions on fork() and threads, it's legal to 269 * fork() before creating any threads. 270 */ 271 pthread_atfork(NULL, NULL, pthread__child_callback); 272 } 273 274 275 /* General-purpose thread data structure sanitization. */ 276 /* ARGSUSED */ 277 static void 278 pthread__initthread(pthread_t t) 279 { 280 281 t->pt_self = t; 282 t->pt_magic = PT_MAGIC; 283 t->pt_willpark = 0; 284 t->pt_unpark = 0; 285 t->pt_nwaiters = 0; 286 t->pt_sleepobj = NULL; 287 t->pt_signalled = 0; 288 t->pt_havespecific = 0; 289 t->pt_early = NULL; 290 t->pt_lwpctl = &pthread__dummy_lwpctl; 291 t->pt_blocking = 0; 292 t->pt_droplock = NULL; 293 294 memcpy(&t->pt_lockops, pthread__lock_ops, sizeof(t->pt_lockops)); 295 pthread_mutex_init(&t->pt_lock, NULL); 296 PTQ_INIT(&t->pt_cleanup_stack); 297 pthread_cond_init(&t->pt_joiners, NULL); 298 memset(&t->pt_specific, 0, sizeof(t->pt_specific)); 299 } 300 301 static void 302 pthread__scrubthread(pthread_t t, char *name, int flags) 303 { 304 305 t->pt_state = PT_STATE_RUNNING; 306 t->pt_exitval = NULL; 307 t->pt_flags = flags; 308 t->pt_cancel = 0; 309 t->pt_errno = 0; 310 t->pt_name = name; 311 t->pt_lid = 0; 312 } 313 314 315 int 316 pthread_create(pthread_t *thread, const pthread_attr_t *attr, 317 void *(*startfunc)(void *), void *arg) 318 { 319 pthread_t newthread; 320 pthread_attr_t nattr; 321 struct pthread_attr_private *p; 322 char * volatile name; 323 unsigned long flag; 324 int ret; 325 326 /* 327 * It's okay to check this without a lock because there can 328 * only be one thread before it becomes true. 329 */ 330 if (pthread__started == 0) { 331 pthread__start(); 332 pthread__started = 1; 333 } 334 335 if (attr == NULL) 336 nattr = pthread_default_attr; 337 else if (attr->pta_magic == PT_ATTR_MAGIC) 338 nattr = *attr; 339 else 340 return EINVAL; 341 342 /* Fetch misc. attributes from the attr structure. */ 343 name = NULL; 344 if ((p = nattr.pta_private) != NULL) 345 if (p->ptap_name[0] != '\0') 346 if ((name = strdup(p->ptap_name)) == NULL) 347 return ENOMEM; 348 349 newthread = NULL; 350 351 /* 352 * Try to reclaim a dead thread. 353 */ 354 if (!PTQ_EMPTY(&pthread__deadqueue)) { 355 pthread_mutex_lock(&pthread__deadqueue_lock); 356 newthread = PTQ_FIRST(&pthread__deadqueue); 357 if (newthread != NULL) { 358 PTQ_REMOVE(&pthread__deadqueue, newthread, pt_deadq); 359 pthread_mutex_unlock(&pthread__deadqueue_lock); 360 /* Still running? */ 361 if (newthread->pt_lwpctl->lc_curcpu != 362 LWPCTL_CPU_EXITED && 363 (_lwp_kill(newthread->pt_lid, 0) == 0 || 364 errno != ESRCH)) { 365 pthread_mutex_lock(&pthread__deadqueue_lock); 366 PTQ_INSERT_TAIL(&pthread__deadqueue, 367 newthread, pt_deadq); 368 pthread_mutex_unlock(&pthread__deadqueue_lock); 369 newthread = NULL; 370 } 371 } else 372 pthread_mutex_unlock(&pthread__deadqueue_lock); 373 } 374 375 /* 376 * If necessary set up a stack, allocate space for a pthread_st, 377 * and initialize it. 378 */ 379 if (newthread == NULL) { 380 ret = pthread__stackalloc(&newthread); 381 if (ret != 0) { 382 if (name) 383 free(name); 384 return ret; 385 } 386 387 /* This is used only when creating the thread. */ 388 _INITCONTEXT_U(&newthread->pt_uc); 389 #ifdef PTHREAD_MACHINE_HAS_ID_REGISTER 390 pthread__uc_id(&newthread->pt_uc) = newthread; 391 #endif 392 newthread->pt_uc.uc_stack = newthread->pt_stack; 393 newthread->pt_uc.uc_link = NULL; 394 395 /* Add to list of all threads. */ 396 pthread_rwlock_wrlock(&pthread__alltree_lock); 397 PTQ_INSERT_TAIL(&pthread__allqueue, newthread, pt_allq); 398 RB_INSERT(__pthread__alltree, &pthread__alltree, newthread); 399 pthread_rwlock_unlock(&pthread__alltree_lock); 400 401 /* Will be reset by the thread upon exit. */ 402 pthread__initthread(newthread); 403 } 404 405 /* 406 * Create the new LWP. 407 */ 408 pthread__scrubthread(newthread, name, nattr.pta_flags); 409 newthread->pt_func = startfunc; 410 newthread->pt_arg = arg; 411 _lwp_makecontext(&newthread->pt_uc, pthread__create_tramp, 412 newthread, newthread, newthread->pt_stack.ss_sp, 413 newthread->pt_stack.ss_size); 414 415 flag = LWP_DETACHED; 416 if ((newthread->pt_flags & PT_FLAG_SUSPENDED) != 0 || 417 (nattr.pta_flags & PT_FLAG_EXPLICIT_SCHED) != 0) 418 flag |= LWP_SUSPENDED; 419 ret = _lwp_create(&newthread->pt_uc, flag, &newthread->pt_lid); 420 if (ret != 0) { 421 free(name); 422 newthread->pt_state = PT_STATE_DEAD; 423 pthread_mutex_lock(&pthread__deadqueue_lock); 424 PTQ_INSERT_HEAD(&pthread__deadqueue, newthread, pt_deadq); 425 pthread_mutex_unlock(&pthread__deadqueue_lock); 426 return ret; 427 } 428 429 if ((nattr.pta_flags & PT_FLAG_EXPLICIT_SCHED) != 0) { 430 if (p != NULL) { 431 (void)pthread_setschedparam(newthread, p->ptap_policy, 432 &p->ptap_sp); 433 } 434 if ((newthread->pt_flags & PT_FLAG_SUSPENDED) == 0) { 435 (void)_lwp_continue(newthread->pt_lid); 436 } 437 } 438 439 *thread = newthread; 440 441 return 0; 442 } 443 444 445 static void 446 pthread__create_tramp(void *cookie) 447 { 448 pthread_t self; 449 void *retval; 450 451 self = cookie; 452 453 /* 454 * Throw away some stack in a feeble attempt to reduce cache 455 * thrash. May help for SMT processors. XXX We should not 456 * be allocating stacks on fixed 2MB boundaries. Needs a 457 * thread register or decent thread local storage. 458 * 459 * Note that we may race with the kernel in _lwp_create(), 460 * and so pt_lid can be unset at this point, but we don't 461 * care. 462 */ 463 (void)alloca(((unsigned)self->pt_lid & 7) << 8); 464 465 if (self->pt_name != NULL) { 466 pthread_mutex_lock(&self->pt_lock); 467 if (self->pt_name != NULL) 468 (void)_lwp_setname(0, self->pt_name); 469 pthread_mutex_unlock(&self->pt_lock); 470 } 471 472 if (_lwp_ctl(LWPCTL_FEATURE_CURCPU, &self->pt_lwpctl)) { 473 err(1, "_lwp_ctl"); 474 } 475 476 retval = (*self->pt_func)(self->pt_arg); 477 478 pthread_exit(retval); 479 480 /*NOTREACHED*/ 481 pthread__abort(); 482 } 483 484 int 485 pthread_suspend_np(pthread_t thread) 486 { 487 pthread_t self; 488 489 self = pthread__self(); 490 if (self == thread) { 491 return EDEADLK; 492 } 493 if (pthread__find(thread) != 0) 494 return ESRCH; 495 if (_lwp_suspend(thread->pt_lid) == 0) 496 return 0; 497 return errno; 498 } 499 500 int 501 pthread_resume_np(pthread_t thread) 502 { 503 504 if (pthread__find(thread) != 0) 505 return ESRCH; 506 if (_lwp_continue(thread->pt_lid) == 0) 507 return 0; 508 return errno; 509 } 510 511 void 512 pthread_exit(void *retval) 513 { 514 pthread_t self; 515 struct pt_clean_t *cleanup; 516 char *name; 517 518 self = pthread__self(); 519 520 /* Disable cancellability. */ 521 pthread_mutex_lock(&self->pt_lock); 522 self->pt_flags |= PT_FLAG_CS_DISABLED; 523 self->pt_cancel = 0; 524 525 /* Call any cancellation cleanup handlers */ 526 if (!PTQ_EMPTY(&self->pt_cleanup_stack)) { 527 pthread_mutex_unlock(&self->pt_lock); 528 while (!PTQ_EMPTY(&self->pt_cleanup_stack)) { 529 cleanup = PTQ_FIRST(&self->pt_cleanup_stack); 530 PTQ_REMOVE(&self->pt_cleanup_stack, cleanup, ptc_next); 531 (*cleanup->ptc_cleanup)(cleanup->ptc_arg); 532 } 533 pthread_mutex_lock(&self->pt_lock); 534 } 535 536 /* Perform cleanup of thread-specific data */ 537 pthread__destroy_tsd(self); 538 539 /* Signal our exit. */ 540 self->pt_exitval = retval; 541 if (self->pt_flags & PT_FLAG_DETACHED) { 542 self->pt_state = PT_STATE_DEAD; 543 name = self->pt_name; 544 self->pt_name = NULL; 545 pthread_mutex_unlock(&self->pt_lock); 546 if (name != NULL) 547 free(name); 548 pthread_mutex_lock(&pthread__deadqueue_lock); 549 PTQ_INSERT_TAIL(&pthread__deadqueue, self, pt_deadq); 550 pthread_mutex_unlock(&pthread__deadqueue_lock); 551 _lwp_exit(); 552 } else { 553 self->pt_state = PT_STATE_ZOMBIE; 554 pthread_cond_broadcast(&self->pt_joiners); 555 pthread_mutex_unlock(&self->pt_lock); 556 /* Note: name will be freed by the joiner. */ 557 _lwp_exit(); 558 } 559 560 /*NOTREACHED*/ 561 pthread__abort(); 562 exit(1); 563 } 564 565 566 int 567 pthread_join(pthread_t thread, void **valptr) 568 { 569 pthread_t self; 570 int error; 571 572 self = pthread__self(); 573 574 if (pthread__find(thread) != 0) 575 return ESRCH; 576 577 if (thread->pt_magic != PT_MAGIC) 578 return EINVAL; 579 580 if (thread == self) 581 return EDEADLK; 582 583 self->pt_droplock = &thread->pt_lock; 584 pthread_mutex_lock(&thread->pt_lock); 585 for (;;) { 586 if (thread->pt_state == PT_STATE_ZOMBIE) 587 break; 588 if (thread->pt_state == PT_STATE_DEAD) { 589 pthread_mutex_unlock(&thread->pt_lock); 590 self->pt_droplock = NULL; 591 return ESRCH; 592 } 593 if ((thread->pt_flags & PT_FLAG_DETACHED) != 0) { 594 pthread_mutex_unlock(&thread->pt_lock); 595 self->pt_droplock = NULL; 596 return EINVAL; 597 } 598 error = pthread_cond_wait(&thread->pt_joiners, 599 &thread->pt_lock); 600 if (error != 0) { 601 pthread__errorfunc(__FILE__, __LINE__, 602 __func__, "unexpected return from cond_wait()"); 603 } 604 605 } 606 pthread__testcancel(self); 607 if (valptr != NULL) 608 *valptr = thread->pt_exitval; 609 /* pthread__reap() will drop the lock. */ 610 pthread__reap(thread); 611 self->pt_droplock = NULL; 612 613 return 0; 614 } 615 616 static void 617 pthread__reap(pthread_t thread) 618 { 619 char *name; 620 621 name = thread->pt_name; 622 thread->pt_name = NULL; 623 thread->pt_state = PT_STATE_DEAD; 624 pthread_mutex_unlock(&thread->pt_lock); 625 626 pthread_mutex_lock(&pthread__deadqueue_lock); 627 PTQ_INSERT_HEAD(&pthread__deadqueue, thread, pt_deadq); 628 pthread_mutex_unlock(&pthread__deadqueue_lock); 629 630 if (name != NULL) 631 free(name); 632 } 633 634 int 635 pthread_equal(pthread_t t1, pthread_t t2) 636 { 637 638 /* Nothing special here. */ 639 return (t1 == t2); 640 } 641 642 643 int 644 pthread_detach(pthread_t thread) 645 { 646 647 if (pthread__find(thread) != 0) 648 return ESRCH; 649 650 if (thread->pt_magic != PT_MAGIC) 651 return EINVAL; 652 653 pthread_mutex_lock(&thread->pt_lock); 654 thread->pt_flags |= PT_FLAG_DETACHED; 655 if (thread->pt_state == PT_STATE_ZOMBIE) { 656 /* pthread__reap() will drop the lock. */ 657 pthread__reap(thread); 658 } else { 659 /* 660 * Not valid for threads to be waiting in 661 * pthread_join() (there are intractable 662 * sync issues from the application 663 * perspective), but give those threads 664 * a chance anyway. 665 */ 666 pthread_cond_broadcast(&thread->pt_joiners); 667 pthread_mutex_unlock(&thread->pt_lock); 668 } 669 670 return 0; 671 } 672 673 674 int 675 pthread_getname_np(pthread_t thread, char *name, size_t len) 676 { 677 678 if (pthread__find(thread) != 0) 679 return ESRCH; 680 681 if (thread->pt_magic != PT_MAGIC) 682 return EINVAL; 683 684 pthread_mutex_lock(&thread->pt_lock); 685 if (thread->pt_name == NULL) 686 name[0] = '\0'; 687 else 688 strlcpy(name, thread->pt_name, len); 689 pthread_mutex_unlock(&thread->pt_lock); 690 691 return 0; 692 } 693 694 695 int 696 pthread_setname_np(pthread_t thread, const char *name, void *arg) 697 { 698 char *oldname, *cp, newname[PTHREAD_MAX_NAMELEN_NP]; 699 int namelen; 700 701 if (pthread__find(thread) != 0) 702 return ESRCH; 703 704 if (thread->pt_magic != PT_MAGIC) 705 return EINVAL; 706 707 namelen = snprintf(newname, sizeof(newname), name, arg); 708 if (namelen >= PTHREAD_MAX_NAMELEN_NP) 709 return EINVAL; 710 711 cp = strdup(newname); 712 if (cp == NULL) 713 return ENOMEM; 714 715 pthread_mutex_lock(&thread->pt_lock); 716 oldname = thread->pt_name; 717 thread->pt_name = cp; 718 (void)_lwp_setname(thread->pt_lid, cp); 719 pthread_mutex_unlock(&thread->pt_lock); 720 721 if (oldname != NULL) 722 free(oldname); 723 724 return 0; 725 } 726 727 728 729 /* 730 * XXX There should be a way for applications to use the efficent 731 * inline version, but there are opacity/namespace issues. 732 */ 733 pthread_t 734 pthread_self(void) 735 { 736 737 return pthread__self(); 738 } 739 740 741 int 742 pthread_cancel(pthread_t thread) 743 { 744 745 if (pthread__find(thread) != 0) 746 return ESRCH; 747 pthread_mutex_lock(&thread->pt_lock); 748 thread->pt_flags |= PT_FLAG_CS_PENDING; 749 if ((thread->pt_flags & PT_FLAG_CS_DISABLED) == 0) { 750 thread->pt_cancel = 1; 751 pthread_mutex_unlock(&thread->pt_lock); 752 _lwp_wakeup(thread->pt_lid); 753 } else 754 pthread_mutex_unlock(&thread->pt_lock); 755 756 return 0; 757 } 758 759 760 int 761 pthread_setcancelstate(int state, int *oldstate) 762 { 763 pthread_t self; 764 int retval; 765 766 self = pthread__self(); 767 retval = 0; 768 769 pthread_mutex_lock(&self->pt_lock); 770 771 if (oldstate != NULL) { 772 if (self->pt_flags & PT_FLAG_CS_DISABLED) 773 *oldstate = PTHREAD_CANCEL_DISABLE; 774 else 775 *oldstate = PTHREAD_CANCEL_ENABLE; 776 } 777 778 if (state == PTHREAD_CANCEL_DISABLE) { 779 self->pt_flags |= PT_FLAG_CS_DISABLED; 780 if (self->pt_cancel) { 781 self->pt_flags |= PT_FLAG_CS_PENDING; 782 self->pt_cancel = 0; 783 } 784 } else if (state == PTHREAD_CANCEL_ENABLE) { 785 self->pt_flags &= ~PT_FLAG_CS_DISABLED; 786 /* 787 * If a cancellation was requested while cancellation 788 * was disabled, note that fact for future 789 * cancellation tests. 790 */ 791 if (self->pt_flags & PT_FLAG_CS_PENDING) { 792 self->pt_cancel = 1; 793 /* This is not a deferred cancellation point. */ 794 if (self->pt_flags & PT_FLAG_CS_ASYNC) { 795 pthread_mutex_unlock(&self->pt_lock); 796 pthread__cancelled(); 797 } 798 } 799 } else 800 retval = EINVAL; 801 802 pthread_mutex_unlock(&self->pt_lock); 803 804 return retval; 805 } 806 807 808 int 809 pthread_setcanceltype(int type, int *oldtype) 810 { 811 pthread_t self; 812 int retval; 813 814 self = pthread__self(); 815 retval = 0; 816 817 pthread_mutex_lock(&self->pt_lock); 818 819 if (oldtype != NULL) { 820 if (self->pt_flags & PT_FLAG_CS_ASYNC) 821 *oldtype = PTHREAD_CANCEL_ASYNCHRONOUS; 822 else 823 *oldtype = PTHREAD_CANCEL_DEFERRED; 824 } 825 826 if (type == PTHREAD_CANCEL_ASYNCHRONOUS) { 827 self->pt_flags |= PT_FLAG_CS_ASYNC; 828 if (self->pt_cancel) { 829 pthread_mutex_unlock(&self->pt_lock); 830 pthread__cancelled(); 831 } 832 } else if (type == PTHREAD_CANCEL_DEFERRED) 833 self->pt_flags &= ~PT_FLAG_CS_ASYNC; 834 else 835 retval = EINVAL; 836 837 pthread_mutex_unlock(&self->pt_lock); 838 839 return retval; 840 } 841 842 843 void 844 pthread_testcancel(void) 845 { 846 pthread_t self; 847 848 self = pthread__self(); 849 if (self->pt_cancel) 850 pthread__cancelled(); 851 } 852 853 854 /* 855 * POSIX requires that certain functions return an error rather than 856 * invoking undefined behavior even when handed completely bogus 857 * pthread_t values, e.g. stack garbage or (pthread_t)666. This 858 * utility routine searches the list of threads for the pthread_t 859 * value without dereferencing it. 860 */ 861 int 862 pthread__find(pthread_t id) 863 { 864 pthread_t target; 865 866 pthread_rwlock_rdlock(&pthread__alltree_lock); 867 /* LINTED */ 868 target = RB_FIND(__pthread__alltree, &pthread__alltree, id); 869 pthread_rwlock_unlock(&pthread__alltree_lock); 870 871 if (target == NULL || target->pt_state == PT_STATE_DEAD) 872 return ESRCH; 873 874 return 0; 875 } 876 877 878 void 879 pthread__testcancel(pthread_t self) 880 { 881 882 if (self->pt_cancel) 883 pthread__cancelled(); 884 } 885 886 887 void 888 pthread__cancelled(void) 889 { 890 pthread_mutex_t *droplock; 891 pthread_t self; 892 893 self = pthread__self(); 894 droplock = self->pt_droplock; 895 self->pt_droplock = NULL; 896 897 if (droplock != NULL && pthread_mutex_held_np(droplock)) 898 pthread_mutex_unlock(droplock); 899 900 pthread_exit(PTHREAD_CANCELED); 901 } 902 903 904 void 905 pthread__cleanup_push(void (*cleanup)(void *), void *arg, void *store) 906 { 907 pthread_t self; 908 struct pt_clean_t *entry; 909 910 self = pthread__self(); 911 entry = store; 912 entry->ptc_cleanup = cleanup; 913 entry->ptc_arg = arg; 914 PTQ_INSERT_HEAD(&self->pt_cleanup_stack, entry, ptc_next); 915 } 916 917 918 void 919 pthread__cleanup_pop(int ex, void *store) 920 { 921 pthread_t self; 922 struct pt_clean_t *entry; 923 924 self = pthread__self(); 925 entry = store; 926 927 PTQ_REMOVE(&self->pt_cleanup_stack, entry, ptc_next); 928 if (ex) 929 (*entry->ptc_cleanup)(entry->ptc_arg); 930 } 931 932 933 int * 934 pthread__errno(void) 935 { 936 pthread_t self; 937 938 self = pthread__self(); 939 940 return &(self->pt_errno); 941 } 942 943 ssize_t _sys_write(int, const void *, size_t); 944 945 void 946 pthread__assertfunc(const char *file, int line, const char *function, 947 const char *expr) 948 { 949 char buf[1024]; 950 int len; 951 952 /* 953 * snprintf should not acquire any locks, or we could 954 * end up deadlocked if the assert caller held locks. 955 */ 956 len = snprintf(buf, 1024, 957 "assertion \"%s\" failed: file \"%s\", line %d%s%s%s\n", 958 expr, file, line, 959 function ? ", function \"" : "", 960 function ? function : "", 961 function ? "\"" : ""); 962 963 _sys_write(STDERR_FILENO, buf, (size_t)len); 964 (void)kill(getpid(), SIGABRT); 965 966 _exit(1); 967 } 968 969 970 void 971 pthread__errorfunc(const char *file, int line, const char *function, 972 const char *msg) 973 { 974 char buf[1024]; 975 size_t len; 976 977 if (pthread__diagassert == 0) 978 return; 979 980 /* 981 * snprintf should not acquire any locks, or we could 982 * end up deadlocked if the assert caller held locks. 983 */ 984 len = snprintf(buf, 1024, 985 "%s: Error detected by libpthread: %s.\n" 986 "Detected by file \"%s\", line %d%s%s%s.\n" 987 "See pthread(3) for information.\n", 988 getprogname(), msg, file, line, 989 function ? ", function \"" : "", 990 function ? function : "", 991 function ? "\"" : ""); 992 993 if (pthread__diagassert & DIAGASSERT_STDERR) 994 _sys_write(STDERR_FILENO, buf, len); 995 996 if (pthread__diagassert & DIAGASSERT_SYSLOG) 997 syslog(LOG_DEBUG | LOG_USER, "%s", buf); 998 999 if (pthread__diagassert & DIAGASSERT_ABORT) { 1000 (void)kill(getpid(), SIGABRT); 1001 _exit(1); 1002 } 1003 } 1004 1005 /* 1006 * Thread park/unpark operations. The kernel operations are 1007 * modelled after a brief description from "Multithreading in 1008 * the Solaris Operating Environment": 1009 * 1010 * http://www.sun.com/software/whitepapers/solaris9/multithread.pdf 1011 */ 1012 1013 #define OOPS(msg) \ 1014 pthread__errorfunc(__FILE__, __LINE__, __func__, msg) 1015 1016 int 1017 pthread__park(pthread_t self, pthread_mutex_t *lock, 1018 pthread_queue_t *queue, const struct timespec *abstime, 1019 int cancelpt, const void *hint) 1020 { 1021 int rv, error; 1022 void *obj; 1023 1024 /* 1025 * For non-interlocked release of mutexes we need a store 1026 * barrier before incrementing pt_blocking away from zero. 1027 * This is provided by pthread_mutex_unlock(). 1028 */ 1029 self->pt_willpark = 1; 1030 pthread_mutex_unlock(lock); 1031 self->pt_willpark = 0; 1032 self->pt_blocking++; 1033 1034 /* 1035 * Wait until we are awoken by a pending unpark operation, 1036 * a signal, an unpark posted after we have gone asleep, 1037 * or an expired timeout. 1038 * 1039 * It is fine to test the value of pt_sleepobj without 1040 * holding any locks, because: 1041 * 1042 * o Only the blocking thread (this thread) ever sets them 1043 * to a non-NULL value. 1044 * 1045 * o Other threads may set them NULL, but if they do so they 1046 * must also make this thread return from _lwp_park. 1047 * 1048 * o _lwp_park, _lwp_unpark and _lwp_unpark_all are system 1049 * calls and all make use of spinlocks in the kernel. So 1050 * these system calls act as full memory barriers, and will 1051 * ensure that the calling CPU's store buffers are drained. 1052 * In combination with the spinlock release before unpark, 1053 * this means that modification of pt_sleepobj/onq by another 1054 * thread will become globally visible before that thread 1055 * schedules an unpark operation on this thread. 1056 * 1057 * Note: the test in the while() statement dodges the park op if 1058 * we have already been awoken, unless there is another thread to 1059 * awaken. This saves a syscall - if we were already awakened, 1060 * the next call to _lwp_park() would need to return early in order 1061 * to eat the previous wakeup. 1062 */ 1063 rv = 0; 1064 do { 1065 /* 1066 * If we deferred unparking a thread, arrange to 1067 * have _lwp_park() restart it before blocking. 1068 */ 1069 error = _lwp_park(abstime, self->pt_unpark, hint, hint); 1070 self->pt_unpark = 0; 1071 if (error != 0) { 1072 switch (rv = errno) { 1073 case EINTR: 1074 case EALREADY: 1075 rv = 0; 1076 break; 1077 case ETIMEDOUT: 1078 break; 1079 default: 1080 OOPS("_lwp_park failed"); 1081 break; 1082 } 1083 } 1084 /* Check for cancellation. */ 1085 if (cancelpt && self->pt_cancel) 1086 rv = EINTR; 1087 } while (self->pt_sleepobj != NULL && rv == 0); 1088 1089 /* 1090 * If we have been awoken early but are still on the queue, 1091 * then remove ourself. Again, it's safe to do the test 1092 * without holding any locks. 1093 */ 1094 if (__predict_false(self->pt_sleepobj != NULL)) { 1095 pthread_mutex_lock(lock); 1096 if ((obj = self->pt_sleepobj) != NULL) { 1097 PTQ_REMOVE(queue, self, pt_sleep); 1098 self->pt_sleepobj = NULL; 1099 if (obj != NULL && self->pt_early != NULL) 1100 (*self->pt_early)(obj); 1101 } 1102 pthread_mutex_unlock(lock); 1103 } 1104 self->pt_early = NULL; 1105 self->pt_blocking--; 1106 membar_sync(); 1107 1108 return rv; 1109 } 1110 1111 void 1112 pthread__unpark(pthread_queue_t *queue, pthread_t self, 1113 pthread_mutex_t *interlock) 1114 { 1115 pthread_t target; 1116 u_int max; 1117 size_t nwaiters; 1118 1119 max = pthread__unpark_max; 1120 nwaiters = self->pt_nwaiters; 1121 target = PTQ_FIRST(queue); 1122 if (nwaiters == max) { 1123 /* Overflow. */ 1124 (void)_lwp_unpark_all(self->pt_waiters, nwaiters, 1125 __UNVOLATILE(&interlock->ptm_waiters)); 1126 nwaiters = 0; 1127 } 1128 target->pt_sleepobj = NULL; 1129 self->pt_waiters[nwaiters++] = target->pt_lid; 1130 PTQ_REMOVE(queue, target, pt_sleep); 1131 self->pt_nwaiters = nwaiters; 1132 pthread__mutex_deferwake(self, interlock); 1133 } 1134 1135 void 1136 pthread__unpark_all(pthread_queue_t *queue, pthread_t self, 1137 pthread_mutex_t *interlock) 1138 { 1139 pthread_t target; 1140 u_int max; 1141 size_t nwaiters; 1142 1143 max = pthread__unpark_max; 1144 nwaiters = self->pt_nwaiters; 1145 PTQ_FOREACH(target, queue, pt_sleep) { 1146 if (nwaiters == max) { 1147 /* Overflow. */ 1148 (void)_lwp_unpark_all(self->pt_waiters, nwaiters, 1149 __UNVOLATILE(&interlock->ptm_waiters)); 1150 nwaiters = 0; 1151 } 1152 target->pt_sleepobj = NULL; 1153 self->pt_waiters[nwaiters++] = target->pt_lid; 1154 } 1155 self->pt_nwaiters = nwaiters; 1156 PTQ_INIT(queue); 1157 pthread__mutex_deferwake(self, interlock); 1158 } 1159 1160 #undef OOPS 1161 1162 /* 1163 * Allocate a stack for a thread, and set it up. It needs to be aligned, so 1164 * that a thread can find itself by its stack pointer. 1165 */ 1166 static int 1167 pthread__stackalloc(pthread_t *newt) 1168 { 1169 void *addr; 1170 1171 addr = mmap(NULL, pthread__stacksize, PROT_READ|PROT_WRITE, 1172 MAP_ANON|MAP_PRIVATE | MAP_ALIGNED(pthread__stacksize_lg), 1173 -1, (off_t)0); 1174 1175 if (addr == MAP_FAILED) 1176 return ENOMEM; 1177 1178 pthread__assert(((intptr_t)addr & pthread__stackmask) == 0); 1179 1180 return pthread__stackid_setup(addr, pthread__stacksize, newt); 1181 } 1182 1183 1184 /* 1185 * Set up the slightly special stack for the "initial" thread, which 1186 * runs on the normal system stack, and thus gets slightly different 1187 * treatment. 1188 */ 1189 static void 1190 pthread__initmain(pthread_t *newt) 1191 { 1192 struct rlimit slimit; 1193 size_t pagesize; 1194 pthread_t t; 1195 void *base; 1196 size_t size; 1197 int error, ret; 1198 char *value; 1199 1200 pagesize = (size_t)sysconf(_SC_PAGESIZE); 1201 pthread__stacksize = 0; 1202 ret = getrlimit(RLIMIT_STACK, &slimit); 1203 if (ret == -1) 1204 err(1, "Couldn't get stack resource consumption limits"); 1205 1206 value = pthread__getenv("PTHREAD_STACKSIZE"); 1207 if (value != NULL) { 1208 pthread__stacksize = atoi(value) * 1024; 1209 if (pthread__stacksize > slimit.rlim_cur) 1210 pthread__stacksize = (size_t)slimit.rlim_cur; 1211 } 1212 if (pthread__stacksize == 0) 1213 pthread__stacksize = (size_t)slimit.rlim_cur; 1214 if (pthread__stacksize < 4 * pagesize) 1215 errx(1, "Stacksize limit is too low, minimum %zd kbyte.", 1216 4 * pagesize / 1024); 1217 1218 pthread__stacksize_lg = -1; 1219 while (pthread__stacksize) { 1220 pthread__stacksize >>= 1; 1221 pthread__stacksize_lg++; 1222 } 1223 1224 pthread__stacksize = (1 << pthread__stacksize_lg); 1225 pthread__stackmask = pthread__stacksize - 1; 1226 pthread__threadmask = ~pthread__stackmask; 1227 1228 base = (void *)(pthread__sp() & pthread__threadmask); 1229 size = pthread__stacksize; 1230 1231 error = pthread__stackid_setup(base, size, &t); 1232 if (error) { 1233 /* XXX */ 1234 errx(2, "failed to setup main thread: error=%d", error); 1235 } 1236 1237 *newt = t; 1238 1239 /* Set up identity register. */ 1240 (void)_lwp_setprivate(t); 1241 } 1242 1243 static int 1244 /*ARGSUSED*/ 1245 pthread__stackid_setup(void *base, size_t size, pthread_t *tp) 1246 { 1247 pthread_t t; 1248 void *redaddr; 1249 size_t pagesize; 1250 int ret; 1251 1252 t = base; 1253 pagesize = (size_t)sysconf(_SC_PAGESIZE); 1254 1255 /* 1256 * Put a pointer to the pthread in the bottom (but 1257 * redzone-protected section) of the stack. 1258 */ 1259 redaddr = STACK_SHRINK(STACK_MAX(base, size), pagesize); 1260 t->pt_stack.ss_size = size - 2 * pagesize; 1261 #ifdef __MACHINE_STACK_GROWS_UP 1262 t->pt_stack.ss_sp = (char *)(void *)base + pagesize; 1263 #else 1264 t->pt_stack.ss_sp = (char *)(void *)base + 2 * pagesize; 1265 #endif 1266 1267 /* Protect the next-to-bottom stack page as a red zone. */ 1268 ret = mprotect(redaddr, pagesize, PROT_NONE); 1269 if (ret == -1) { 1270 return errno; 1271 } 1272 *tp = t; 1273 return 0; 1274 } 1275 1276 #ifndef lint 1277 static int 1278 pthread__cmp(struct __pthread_st *a, struct __pthread_st *b) 1279 { 1280 1281 if ((uintptr_t)a < (uintptr_t)b) 1282 return (-1); 1283 else if (a == b) 1284 return 0; 1285 else 1286 return 1; 1287 } 1288 RB_GENERATE_STATIC(__pthread__alltree, __pthread_st, pt_alltree, pthread__cmp) 1289 #endif 1290 1291 /* Because getenv() wants to use locks. */ 1292 char * 1293 pthread__getenv(const char *name) 1294 { 1295 extern char *__findenv(const char *, int *); 1296 int off; 1297 1298 return __findenv(name, &off); 1299 } 1300 1301 pthread_mutex_t * 1302 pthread__hashlock(volatile const void *p) 1303 { 1304 uintptr_t v; 1305 1306 v = (uintptr_t)p; 1307 return &hashlocks[((v >> 9) ^ (v >> 3)) & (NHASHLOCK - 1)].mutex; 1308 } 1309 1310 int 1311 pthread__checkpri(int pri) 1312 { 1313 static int havepri; 1314 static long min, max; 1315 1316 if (!havepri) { 1317 min = sysconf(_SC_SCHED_PRI_MIN); 1318 max = sysconf(_SC_SCHED_PRI_MAX); 1319 havepri = 1; 1320 } 1321 return (pri < min || pri > max) ? EINVAL : 0; 1322 } 1323