1 /* $NetBSD: pthread.c,v 1.101 2008/05/25 17:05:28 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 1.101 2008/05/25 17:05:28 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(pthread_t, void *(*)(void *), 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 = DIAGASSERT_ABORT | DIAGASSERT_STDERR; 94 95 int pthread__concurrency; 96 int pthread__nspins; 97 int pthread__unpark_max = PTHREAD__UNPARK_MAX; 98 int pthread__osrev; 99 100 /* 101 * We have to initialize the pthread_stack* variables here because 102 * mutexes are used before pthread_init() and thus pthread__initmain() 103 * are called. Since mutexes only save the stack pointer and not a 104 * pointer to the thread data, it is safe to change the mapping from 105 * stack pointer to thread data afterwards. 106 */ 107 #define _STACKSIZE_LG 18 108 int pthread__stacksize_lg = _STACKSIZE_LG; 109 size_t pthread__stacksize = 1 << _STACKSIZE_LG; 110 vaddr_t pthread__stackmask = (1 << _STACKSIZE_LG) - 1; 111 vaddr_t pthread__threadmask = (vaddr_t)~((1 << _STACKSIZE_LG) - 1); 112 #undef _STACKSIZE_LG 113 114 int _sys___sigprocmask14(int, const sigset_t *, sigset_t *); 115 116 __strong_alias(__libc_thr_self,pthread_self) 117 __strong_alias(__libc_thr_create,pthread_create) 118 __strong_alias(__libc_thr_exit,pthread_exit) 119 __strong_alias(__libc_thr_errno,pthread__errno) 120 __strong_alias(__libc_thr_setcancelstate,pthread_setcancelstate) 121 __strong_alias(__libc_thr_equal,pthread_equal) 122 __strong_alias(__libc_thr_init,pthread__init) 123 124 /* 125 * Static library kludge. Place a reference to a symbol any library 126 * file which does not already have a reference here. 127 */ 128 extern int pthread__cancel_stub_binder; 129 130 void *pthread__static_lib_binder[] = { 131 &pthread__cancel_stub_binder, 132 pthread_cond_init, 133 pthread_mutex_init, 134 pthread_rwlock_init, 135 pthread_barrier_init, 136 pthread_key_create, 137 pthread_setspecific, 138 }; 139 140 #define NHASHLOCK 64 141 142 static union hashlock { 143 pthread_mutex_t mutex; 144 char pad[64]; 145 } hashlocks[NHASHLOCK] __aligned(64); 146 147 /* 148 * This needs to be started by the library loading code, before main() 149 * gets to run, for various things that use the state of the initial thread 150 * to work properly (thread-specific data is an application-visible example; 151 * spinlock counts for mutexes is an internal example). 152 */ 153 void 154 pthread__init(void) 155 { 156 pthread_t first; 157 char *p; 158 int i, mib[2]; 159 size_t len; 160 extern int __isthreaded; 161 162 mib[0] = CTL_HW; 163 mib[1] = HW_NCPU; 164 165 len = sizeof(pthread__concurrency); 166 if (sysctl(mib, 2, &pthread__concurrency, &len, NULL, 0) == -1) 167 err(1, "sysctl(hw.ncpu"); 168 169 mib[0] = CTL_KERN; 170 mib[1] = KERN_OSREV; 171 172 len = sizeof(pthread__osrev); 173 if (sysctl(mib, 2, &pthread__osrev, &len, NULL, 0) == -1) 174 err(1, "sysctl(hw.osrevision"); 175 176 /* Initialize locks first; they're needed elsewhere. */ 177 pthread__lockprim_init(); 178 for (i = 0; i < NHASHLOCK; i++) { 179 pthread_mutex_init(&hashlocks[i].mutex, NULL); 180 } 181 182 /* Fetch parameters. */ 183 i = (int)_lwp_unpark_all(NULL, 0, NULL); 184 if (i == -1) 185 err(1, "_lwp_unpark_all"); 186 if (i < pthread__unpark_max) 187 pthread__unpark_max = i; 188 189 /* Basic data structure setup */ 190 pthread_attr_init(&pthread_default_attr); 191 PTQ_INIT(&pthread__allqueue); 192 PTQ_INIT(&pthread__deadqueue); 193 RB_INIT(&pthread__alltree); 194 195 /* Create the thread structure corresponding to main() */ 196 pthread__initmain(&first); 197 pthread__initthread(first); 198 pthread__scrubthread(first, NULL, 0); 199 200 first->pt_lid = _lwp_self(); 201 PTQ_INSERT_HEAD(&pthread__allqueue, first, pt_allq); 202 RB_INSERT(__pthread__alltree, &pthread__alltree, first); 203 204 if (_lwp_ctl(LWPCTL_FEATURE_CURCPU, &first->pt_lwpctl) != 0) { 205 err(1, "_lwp_ctl"); 206 } 207 208 /* Start subsystems */ 209 PTHREAD_MD_INIT 210 211 for (p = pthread__getenv("PTHREAD_DIAGASSERT"); p && *p; p++) { 212 switch (*p) { 213 case 'a': 214 pthread__diagassert |= DIAGASSERT_ABORT; 215 break; 216 case 'A': 217 pthread__diagassert &= ~DIAGASSERT_ABORT; 218 break; 219 case 'e': 220 pthread__diagassert |= DIAGASSERT_STDERR; 221 break; 222 case 'E': 223 pthread__diagassert &= ~DIAGASSERT_STDERR; 224 break; 225 case 'l': 226 pthread__diagassert |= DIAGASSERT_SYSLOG; 227 break; 228 case 'L': 229 pthread__diagassert &= ~DIAGASSERT_SYSLOG; 230 break; 231 } 232 } 233 234 /* Tell libc that we're here and it should role-play accordingly. */ 235 pthread__first = first; 236 pthread_atfork(NULL, NULL, pthread__fork_callback); 237 __isthreaded = 1; 238 } 239 240 static void 241 pthread__fork_callback(void) 242 { 243 244 /* lwpctl state is not copied across fork. */ 245 if (_lwp_ctl(LWPCTL_FEATURE_CURCPU, &pthread__first->pt_lwpctl)) { 246 err(1, "_lwp_ctl"); 247 } 248 } 249 250 static void 251 pthread__child_callback(void) 252 { 253 254 /* 255 * Clean up data structures that a forked child process might 256 * trip over. Note that if threads have been created (causing 257 * this handler to be registered) the standards say that the 258 * child will trigger undefined behavior if it makes any 259 * pthread_* calls (or any other calls that aren't 260 * async-signal-safe), so we don't really have to clean up 261 * much. Anything that permits some pthread_* calls to work is 262 * merely being polite. 263 */ 264 pthread__started = 0; 265 } 266 267 static void 268 pthread__start(void) 269 { 270 271 /* 272 * Per-process timers are cleared by fork(); despite the 273 * various restrictions on fork() and threads, it's legal to 274 * fork() before creating any threads. 275 */ 276 pthread_atfork(NULL, NULL, pthread__child_callback); 277 } 278 279 280 /* General-purpose thread data structure sanitization. */ 281 /* ARGSUSED */ 282 static void 283 pthread__initthread(pthread_t t) 284 { 285 286 t->pt_self = t; 287 t->pt_magic = PT_MAGIC; 288 t->pt_willpark = 0; 289 t->pt_unpark = 0; 290 t->pt_nwaiters = 0; 291 t->pt_sleepobj = NULL; 292 t->pt_signalled = 0; 293 t->pt_havespecific = 0; 294 t->pt_early = NULL; 295 t->pt_lwpctl = &pthread__dummy_lwpctl; 296 t->pt_blocking = 0; 297 t->pt_droplock = NULL; 298 299 memcpy(&t->pt_lockops, pthread__lock_ops, sizeof(t->pt_lockops)); 300 pthread_mutex_init(&t->pt_lock, NULL); 301 PTQ_INIT(&t->pt_cleanup_stack); 302 pthread_cond_init(&t->pt_joiners, NULL); 303 memset(&t->pt_specific, 0, sizeof(t->pt_specific)); 304 } 305 306 static void 307 pthread__scrubthread(pthread_t t, char *name, int flags) 308 { 309 310 t->pt_state = PT_STATE_RUNNING; 311 t->pt_exitval = NULL; 312 t->pt_flags = flags; 313 t->pt_cancel = 0; 314 t->pt_errno = 0; 315 t->pt_name = name; 316 t->pt_lid = 0; 317 } 318 319 320 int 321 pthread_create(pthread_t *thread, const pthread_attr_t *attr, 322 void *(*startfunc)(void *), void *arg) 323 { 324 pthread_t newthread; 325 pthread_attr_t nattr; 326 struct pthread_attr_private *p; 327 char * volatile name; 328 unsigned long flag; 329 int ret; 330 331 /* 332 * It's okay to check this without a lock because there can 333 * only be one thread before it becomes true. 334 */ 335 if (pthread__started == 0) { 336 pthread__start(); 337 pthread__started = 1; 338 } 339 340 if (attr == NULL) 341 nattr = pthread_default_attr; 342 else if (attr->pta_magic == PT_ATTR_MAGIC) 343 nattr = *attr; 344 else 345 return EINVAL; 346 347 /* Fetch misc. attributes from the attr structure. */ 348 name = NULL; 349 if ((p = nattr.pta_private) != NULL) 350 if (p->ptap_name[0] != '\0') 351 if ((name = strdup(p->ptap_name)) == NULL) 352 return ENOMEM; 353 354 newthread = NULL; 355 356 /* 357 * Try to reclaim a dead thread. 358 */ 359 if (!PTQ_EMPTY(&pthread__deadqueue)) { 360 pthread_mutex_lock(&pthread__deadqueue_lock); 361 newthread = PTQ_FIRST(&pthread__deadqueue); 362 if (newthread != NULL) { 363 PTQ_REMOVE(&pthread__deadqueue, newthread, pt_deadq); 364 pthread_mutex_unlock(&pthread__deadqueue_lock); 365 /* Still running? */ 366 if (newthread->pt_lwpctl->lc_curcpu != 367 LWPCTL_CPU_EXITED && 368 (_lwp_kill(newthread->pt_lid, 0) == 0 || 369 errno != ESRCH)) { 370 pthread_mutex_lock(&pthread__deadqueue_lock); 371 PTQ_INSERT_TAIL(&pthread__deadqueue, 372 newthread, pt_deadq); 373 pthread_mutex_unlock(&pthread__deadqueue_lock); 374 newthread = NULL; 375 } 376 } else 377 pthread_mutex_unlock(&pthread__deadqueue_lock); 378 } 379 380 /* 381 * If necessary set up a stack, allocate space for a pthread_st, 382 * and initialize it. 383 */ 384 if (newthread == NULL) { 385 ret = pthread__stackalloc(&newthread); 386 if (ret != 0) { 387 if (name) 388 free(name); 389 return ret; 390 } 391 392 /* This is used only when creating the thread. */ 393 _INITCONTEXT_U(&newthread->pt_uc); 394 #ifdef PTHREAD_MACHINE_HAS_ID_REGISTER 395 pthread__uc_id(&newthread->pt_uc) = newthread; 396 #endif 397 newthread->pt_uc.uc_stack = newthread->pt_stack; 398 newthread->pt_uc.uc_link = NULL; 399 400 /* Add to list of all threads. */ 401 pthread_rwlock_wrlock(&pthread__alltree_lock); 402 PTQ_INSERT_TAIL(&pthread__allqueue, newthread, pt_allq); 403 RB_INSERT(__pthread__alltree, &pthread__alltree, newthread); 404 pthread_rwlock_unlock(&pthread__alltree_lock); 405 406 /* Will be reset by the thread upon exit. */ 407 pthread__initthread(newthread); 408 } 409 410 /* 411 * Create the new LWP. 412 */ 413 pthread__scrubthread(newthread, name, nattr.pta_flags); 414 makecontext(&newthread->pt_uc, pthread__create_tramp, 3, 415 newthread, startfunc, arg); 416 417 flag = LWP_DETACHED; 418 if ((newthread->pt_flags & PT_FLAG_SUSPENDED) != 0) 419 flag |= LWP_SUSPENDED; 420 ret = _lwp_create(&newthread->pt_uc, flag, &newthread->pt_lid); 421 if (ret != 0) { 422 free(name); 423 newthread->pt_state = PT_STATE_DEAD; 424 pthread_mutex_lock(&pthread__deadqueue_lock); 425 PTQ_INSERT_HEAD(&pthread__deadqueue, newthread, pt_deadq); 426 pthread_mutex_unlock(&pthread__deadqueue_lock); 427 return ret; 428 } 429 430 *thread = newthread; 431 432 return 0; 433 } 434 435 436 static void 437 pthread__create_tramp(pthread_t self, void *(*start)(void *), void *arg) 438 { 439 void *retval; 440 441 #ifdef PTHREAD__HAVE_THREADREG 442 /* Set up identity register. */ 443 pthread__threadreg_set(self); 444 #endif 445 446 /* 447 * Throw away some stack in a feeble attempt to reduce cache 448 * thrash. May help for SMT processors. XXX We should not 449 * be allocating stacks on fixed 2MB boundaries. Needs a 450 * thread register or decent thread local storage. Note 451 * that pt_lid may not be set by this point, but we don't 452 * care. 453 */ 454 (void)alloca(((unsigned)self->pt_lid & 7) << 8); 455 456 if (self->pt_name != NULL) { 457 pthread_mutex_lock(&self->pt_lock); 458 if (self->pt_name != NULL) 459 (void)_lwp_setname(0, self->pt_name); 460 pthread_mutex_unlock(&self->pt_lock); 461 } 462 463 if (_lwp_ctl(LWPCTL_FEATURE_CURCPU, &self->pt_lwpctl)) { 464 err(1, "_lwp_ctl"); 465 } 466 467 retval = (*start)(arg); 468 469 pthread_exit(retval); 470 471 /*NOTREACHED*/ 472 pthread__abort(); 473 } 474 475 int 476 pthread_suspend_np(pthread_t thread) 477 { 478 pthread_t self; 479 480 self = pthread__self(); 481 if (self == thread) { 482 return EDEADLK; 483 } 484 if (pthread__find(thread) != 0) 485 return ESRCH; 486 if (_lwp_suspend(thread->pt_lid) == 0) 487 return 0; 488 return errno; 489 } 490 491 int 492 pthread_resume_np(pthread_t thread) 493 { 494 495 if (pthread__find(thread) != 0) 496 return ESRCH; 497 if (_lwp_continue(thread->pt_lid) == 0) 498 return 0; 499 return errno; 500 } 501 502 void 503 pthread_exit(void *retval) 504 { 505 pthread_t self; 506 struct pt_clean_t *cleanup; 507 char *name; 508 509 self = pthread__self(); 510 511 /* Disable cancellability. */ 512 pthread_mutex_lock(&self->pt_lock); 513 self->pt_flags |= PT_FLAG_CS_DISABLED; 514 self->pt_cancel = 0; 515 516 /* Call any cancellation cleanup handlers */ 517 if (!PTQ_EMPTY(&self->pt_cleanup_stack)) { 518 pthread_mutex_unlock(&self->pt_lock); 519 while (!PTQ_EMPTY(&self->pt_cleanup_stack)) { 520 cleanup = PTQ_FIRST(&self->pt_cleanup_stack); 521 PTQ_REMOVE(&self->pt_cleanup_stack, cleanup, ptc_next); 522 (*cleanup->ptc_cleanup)(cleanup->ptc_arg); 523 } 524 pthread_mutex_lock(&self->pt_lock); 525 } 526 527 /* Perform cleanup of thread-specific data */ 528 pthread__destroy_tsd(self); 529 530 /* Signal our exit. */ 531 self->pt_exitval = retval; 532 if (self->pt_flags & PT_FLAG_DETACHED) { 533 self->pt_state = PT_STATE_DEAD; 534 name = self->pt_name; 535 self->pt_name = NULL; 536 pthread_mutex_unlock(&self->pt_lock); 537 if (name != NULL) 538 free(name); 539 pthread_mutex_lock(&pthread__deadqueue_lock); 540 PTQ_INSERT_TAIL(&pthread__deadqueue, self, pt_deadq); 541 pthread_mutex_unlock(&pthread__deadqueue_lock); 542 _lwp_exit(); 543 } else { 544 self->pt_state = PT_STATE_ZOMBIE; 545 pthread_cond_broadcast(&self->pt_joiners); 546 pthread_mutex_unlock(&self->pt_lock); 547 /* Note: name will be freed by the joiner. */ 548 _lwp_exit(); 549 } 550 551 /*NOTREACHED*/ 552 pthread__abort(); 553 exit(1); 554 } 555 556 557 int 558 pthread_join(pthread_t thread, void **valptr) 559 { 560 pthread_t self; 561 int error; 562 563 self = pthread__self(); 564 565 if (pthread__find(thread) != 0) 566 return ESRCH; 567 568 if (thread->pt_magic != PT_MAGIC) 569 return EINVAL; 570 571 if (thread == self) 572 return EDEADLK; 573 574 self->pt_droplock = &thread->pt_lock; 575 pthread_mutex_lock(&thread->pt_lock); 576 for (;;) { 577 if (thread->pt_state == PT_STATE_ZOMBIE) 578 break; 579 if (thread->pt_state == PT_STATE_DEAD) { 580 pthread_mutex_unlock(&thread->pt_lock); 581 self->pt_droplock = NULL; 582 return ESRCH; 583 } 584 if ((thread->pt_flags & PT_FLAG_DETACHED) != 0) { 585 pthread_mutex_unlock(&thread->pt_lock); 586 self->pt_droplock = NULL; 587 return EINVAL; 588 } 589 error = pthread_cond_wait(&thread->pt_joiners, 590 &thread->pt_lock); 591 if (error != 0) { 592 pthread__errorfunc(__FILE__, __LINE__, 593 __func__, "unexpected return from cond_wait()"); 594 } 595 596 } 597 if (valptr != NULL) 598 *valptr = thread->pt_exitval; 599 /* pthread__reap() will drop the lock. */ 600 pthread__reap(thread); 601 self->pt_droplock = NULL; 602 603 return 0; 604 } 605 606 static void 607 pthread__reap(pthread_t thread) 608 { 609 char *name; 610 611 name = thread->pt_name; 612 thread->pt_name = NULL; 613 thread->pt_state = PT_STATE_DEAD; 614 pthread_mutex_unlock(&thread->pt_lock); 615 616 pthread_mutex_lock(&pthread__deadqueue_lock); 617 PTQ_INSERT_HEAD(&pthread__deadqueue, thread, pt_deadq); 618 pthread_mutex_unlock(&pthread__deadqueue_lock); 619 620 if (name != NULL) 621 free(name); 622 } 623 624 int 625 pthread_equal(pthread_t t1, pthread_t t2) 626 { 627 628 /* Nothing special here. */ 629 return (t1 == t2); 630 } 631 632 633 int 634 pthread_detach(pthread_t thread) 635 { 636 637 if (pthread__find(thread) != 0) 638 return ESRCH; 639 640 if (thread->pt_magic != PT_MAGIC) 641 return EINVAL; 642 643 pthread_mutex_lock(&thread->pt_lock); 644 thread->pt_flags |= PT_FLAG_DETACHED; 645 if (thread->pt_state == PT_STATE_ZOMBIE) { 646 /* pthread__reap() will drop the lock. */ 647 pthread__reap(thread); 648 } else { 649 /* 650 * Not valid for threads to be waiting in 651 * pthread_join() (there are intractable 652 * sync issues from the application 653 * perspective), but give those threads 654 * a chance anyway. 655 */ 656 pthread_cond_broadcast(&thread->pt_joiners); 657 pthread_mutex_unlock(&thread->pt_lock); 658 } 659 660 return 0; 661 } 662 663 664 int 665 pthread_getname_np(pthread_t thread, char *name, size_t len) 666 { 667 668 if (pthread__find(thread) != 0) 669 return ESRCH; 670 671 if (thread->pt_magic != PT_MAGIC) 672 return EINVAL; 673 674 pthread_mutex_lock(&thread->pt_lock); 675 if (thread->pt_name == NULL) 676 name[0] = '\0'; 677 else 678 strlcpy(name, thread->pt_name, len); 679 pthread_mutex_unlock(&thread->pt_lock); 680 681 return 0; 682 } 683 684 685 int 686 pthread_setname_np(pthread_t thread, const char *name, void *arg) 687 { 688 char *oldname, *cp, newname[PTHREAD_MAX_NAMELEN_NP]; 689 int namelen; 690 691 if (pthread__find(thread) != 0) 692 return ESRCH; 693 694 if (thread->pt_magic != PT_MAGIC) 695 return EINVAL; 696 697 namelen = snprintf(newname, sizeof(newname), name, arg); 698 if (namelen >= PTHREAD_MAX_NAMELEN_NP) 699 return EINVAL; 700 701 cp = strdup(newname); 702 if (cp == NULL) 703 return ENOMEM; 704 705 pthread_mutex_lock(&thread->pt_lock); 706 oldname = thread->pt_name; 707 thread->pt_name = cp; 708 (void)_lwp_setname(thread->pt_lid, cp); 709 pthread_mutex_unlock(&thread->pt_lock); 710 711 if (oldname != NULL) 712 free(oldname); 713 714 return 0; 715 } 716 717 718 719 /* 720 * XXX There should be a way for applications to use the efficent 721 * inline version, but there are opacity/namespace issues. 722 */ 723 pthread_t 724 pthread_self(void) 725 { 726 727 return pthread__self(); 728 } 729 730 731 int 732 pthread_cancel(pthread_t thread) 733 { 734 735 if (pthread__find(thread) != 0) 736 return ESRCH; 737 pthread_mutex_lock(&thread->pt_lock); 738 thread->pt_flags |= PT_FLAG_CS_PENDING; 739 if ((thread->pt_flags & PT_FLAG_CS_DISABLED) == 0) { 740 thread->pt_cancel = 1; 741 pthread_mutex_unlock(&thread->pt_lock); 742 _lwp_wakeup(thread->pt_lid); 743 } else 744 pthread_mutex_unlock(&thread->pt_lock); 745 746 return 0; 747 } 748 749 750 int 751 pthread_setcancelstate(int state, int *oldstate) 752 { 753 pthread_t self; 754 int retval; 755 756 self = pthread__self(); 757 retval = 0; 758 759 pthread_mutex_lock(&self->pt_lock); 760 761 if (oldstate != NULL) { 762 if (self->pt_flags & PT_FLAG_CS_DISABLED) 763 *oldstate = PTHREAD_CANCEL_DISABLE; 764 else 765 *oldstate = PTHREAD_CANCEL_ENABLE; 766 } 767 768 if (state == PTHREAD_CANCEL_DISABLE) { 769 self->pt_flags |= PT_FLAG_CS_DISABLED; 770 if (self->pt_cancel) { 771 self->pt_flags |= PT_FLAG_CS_PENDING; 772 self->pt_cancel = 0; 773 } 774 } else if (state == PTHREAD_CANCEL_ENABLE) { 775 self->pt_flags &= ~PT_FLAG_CS_DISABLED; 776 /* 777 * If a cancellation was requested while cancellation 778 * was disabled, note that fact for future 779 * cancellation tests. 780 */ 781 if (self->pt_flags & PT_FLAG_CS_PENDING) { 782 self->pt_cancel = 1; 783 /* This is not a deferred cancellation point. */ 784 if (self->pt_flags & PT_FLAG_CS_ASYNC) { 785 pthread_mutex_unlock(&self->pt_lock); 786 pthread__cancelled(); 787 } 788 } 789 } else 790 retval = EINVAL; 791 792 pthread_mutex_unlock(&self->pt_lock); 793 794 return retval; 795 } 796 797 798 int 799 pthread_setcanceltype(int type, int *oldtype) 800 { 801 pthread_t self; 802 int retval; 803 804 self = pthread__self(); 805 retval = 0; 806 807 pthread_mutex_lock(&self->pt_lock); 808 809 if (oldtype != NULL) { 810 if (self->pt_flags & PT_FLAG_CS_ASYNC) 811 *oldtype = PTHREAD_CANCEL_ASYNCHRONOUS; 812 else 813 *oldtype = PTHREAD_CANCEL_DEFERRED; 814 } 815 816 if (type == PTHREAD_CANCEL_ASYNCHRONOUS) { 817 self->pt_flags |= PT_FLAG_CS_ASYNC; 818 if (self->pt_cancel) { 819 pthread_mutex_unlock(&self->pt_lock); 820 pthread__cancelled(); 821 } 822 } else if (type == PTHREAD_CANCEL_DEFERRED) 823 self->pt_flags &= ~PT_FLAG_CS_ASYNC; 824 else 825 retval = EINVAL; 826 827 pthread_mutex_unlock(&self->pt_lock); 828 829 return retval; 830 } 831 832 833 void 834 pthread_testcancel(void) 835 { 836 pthread_t self; 837 838 self = pthread__self(); 839 if (self->pt_cancel) 840 pthread__cancelled(); 841 } 842 843 844 /* 845 * POSIX requires that certain functions return an error rather than 846 * invoking undefined behavior even when handed completely bogus 847 * pthread_t values, e.g. stack garbage or (pthread_t)666. This 848 * utility routine searches the list of threads for the pthread_t 849 * value without dereferencing it. 850 */ 851 int 852 pthread__find(pthread_t id) 853 { 854 pthread_t target; 855 856 pthread_rwlock_rdlock(&pthread__alltree_lock); 857 /* LINTED */ 858 target = RB_FIND(__pthread__alltree, &pthread__alltree, id); 859 pthread_rwlock_unlock(&pthread__alltree_lock); 860 861 if (target == NULL || target->pt_state == PT_STATE_DEAD) 862 return ESRCH; 863 864 return 0; 865 } 866 867 868 void 869 pthread__testcancel(pthread_t self) 870 { 871 872 if (self->pt_cancel) 873 pthread__cancelled(); 874 } 875 876 877 void 878 pthread__cancelled(void) 879 { 880 pthread_mutex_t *droplock; 881 pthread_t self; 882 883 self = pthread__self(); 884 droplock = self->pt_droplock; 885 self->pt_droplock = NULL; 886 887 if (droplock != NULL && pthread_mutex_held_np(droplock)) 888 pthread_mutex_unlock(droplock); 889 890 pthread_exit(PTHREAD_CANCELED); 891 } 892 893 894 void 895 pthread__cleanup_push(void (*cleanup)(void *), void *arg, void *store) 896 { 897 pthread_t self; 898 struct pt_clean_t *entry; 899 900 self = pthread__self(); 901 entry = store; 902 entry->ptc_cleanup = cleanup; 903 entry->ptc_arg = arg; 904 PTQ_INSERT_HEAD(&self->pt_cleanup_stack, entry, ptc_next); 905 } 906 907 908 void 909 pthread__cleanup_pop(int ex, void *store) 910 { 911 pthread_t self; 912 struct pt_clean_t *entry; 913 914 self = pthread__self(); 915 entry = store; 916 917 PTQ_REMOVE(&self->pt_cleanup_stack, entry, ptc_next); 918 if (ex) 919 (*entry->ptc_cleanup)(entry->ptc_arg); 920 } 921 922 923 int * 924 pthread__errno(void) 925 { 926 pthread_t self; 927 928 self = pthread__self(); 929 930 return &(self->pt_errno); 931 } 932 933 ssize_t _sys_write(int, const void *, size_t); 934 935 void 936 pthread__assertfunc(const char *file, int line, const char *function, 937 const char *expr) 938 { 939 char buf[1024]; 940 int len; 941 942 /* 943 * snprintf should not acquire any locks, or we could 944 * end up deadlocked if the assert caller held locks. 945 */ 946 len = snprintf(buf, 1024, 947 "assertion \"%s\" failed: file \"%s\", line %d%s%s%s\n", 948 expr, file, line, 949 function ? ", function \"" : "", 950 function ? function : "", 951 function ? "\"" : ""); 952 953 _sys_write(STDERR_FILENO, buf, (size_t)len); 954 (void)kill(getpid(), SIGABRT); 955 956 _exit(1); 957 } 958 959 960 void 961 pthread__errorfunc(const char *file, int line, const char *function, 962 const char *msg) 963 { 964 char buf[1024]; 965 size_t len; 966 967 if (pthread__diagassert == 0) 968 return; 969 970 /* 971 * snprintf should not acquire any locks, or we could 972 * end up deadlocked if the assert caller held locks. 973 */ 974 len = snprintf(buf, 1024, 975 "%s: Error detected by libpthread: %s.\n" 976 "Detected by file \"%s\", line %d%s%s%s.\n" 977 "See pthread(3) for information.\n", 978 getprogname(), msg, file, line, 979 function ? ", function \"" : "", 980 function ? function : "", 981 function ? "\"" : ""); 982 983 if (pthread__diagassert & DIAGASSERT_STDERR) 984 _sys_write(STDERR_FILENO, buf, len); 985 986 if (pthread__diagassert & DIAGASSERT_SYSLOG) 987 syslog(LOG_DEBUG | LOG_USER, "%s", buf); 988 989 if (pthread__diagassert & DIAGASSERT_ABORT) { 990 (void)kill(getpid(), SIGABRT); 991 _exit(1); 992 } 993 } 994 995 /* 996 * Thread park/unpark operations. The kernel operations are 997 * modelled after a brief description from "Multithreading in 998 * the Solaris Operating Environment": 999 * 1000 * http://www.sun.com/software/whitepapers/solaris9/multithread.pdf 1001 */ 1002 1003 #define OOPS(msg) \ 1004 pthread__errorfunc(__FILE__, __LINE__, __func__, msg) 1005 1006 int 1007 pthread__park(pthread_t self, pthread_mutex_t *lock, 1008 pthread_queue_t *queue, const struct timespec *abstime, 1009 int cancelpt, const void *hint) 1010 { 1011 int rv, error; 1012 void *obj; 1013 1014 /* 1015 * For non-interlocked release of mutexes we need a store 1016 * barrier before incrementing pt_blocking away from zero. 1017 * This is provided by pthread_mutex_unlock(). 1018 */ 1019 self->pt_willpark = 1; 1020 pthread_mutex_unlock(lock); 1021 self->pt_willpark = 0; 1022 self->pt_blocking++; 1023 1024 /* 1025 * Wait until we are awoken by a pending unpark operation, 1026 * a signal, an unpark posted after we have gone asleep, 1027 * or an expired timeout. 1028 * 1029 * It is fine to test the value of pt_sleepobj without 1030 * holding any locks, because: 1031 * 1032 * o Only the blocking thread (this thread) ever sets them 1033 * to a non-NULL value. 1034 * 1035 * o Other threads may set them NULL, but if they do so they 1036 * must also make this thread return from _lwp_park. 1037 * 1038 * o _lwp_park, _lwp_unpark and _lwp_unpark_all are system 1039 * calls and all make use of spinlocks in the kernel. So 1040 * these system calls act as full memory barriers, and will 1041 * ensure that the calling CPU's store buffers are drained. 1042 * In combination with the spinlock release before unpark, 1043 * this means that modification of pt_sleepobj/onq by another 1044 * thread will become globally visible before that thread 1045 * schedules an unpark operation on this thread. 1046 * 1047 * Note: the test in the while() statement dodges the park op if 1048 * we have already been awoken, unless there is another thread to 1049 * awaken. This saves a syscall - if we were already awakened, 1050 * the next call to _lwp_park() would need to return early in order 1051 * to eat the previous wakeup. 1052 */ 1053 rv = 0; 1054 do { 1055 /* 1056 * If we deferred unparking a thread, arrange to 1057 * have _lwp_park() restart it before blocking. 1058 */ 1059 error = _lwp_park(abstime, self->pt_unpark, hint, hint); 1060 self->pt_unpark = 0; 1061 if (error != 0) { 1062 switch (rv = errno) { 1063 case EINTR: 1064 case EALREADY: 1065 rv = 0; 1066 break; 1067 case ETIMEDOUT: 1068 break; 1069 default: 1070 OOPS("_lwp_park failed"); 1071 break; 1072 } 1073 } 1074 /* Check for cancellation. */ 1075 if (cancelpt && self->pt_cancel) 1076 rv = EINTR; 1077 } while (self->pt_sleepobj != NULL && rv == 0); 1078 1079 /* 1080 * If we have been awoken early but are still on the queue, 1081 * then remove ourself. Again, it's safe to do the test 1082 * without holding any locks. 1083 */ 1084 if (__predict_false(self->pt_sleepobj != NULL)) { 1085 pthread_mutex_lock(lock); 1086 if ((obj = self->pt_sleepobj) != NULL) { 1087 PTQ_REMOVE(queue, self, pt_sleep); 1088 self->pt_sleepobj = NULL; 1089 if (obj != NULL && self->pt_early != NULL) 1090 (*self->pt_early)(obj); 1091 } 1092 pthread_mutex_unlock(lock); 1093 } 1094 self->pt_early = NULL; 1095 self->pt_blocking--; 1096 membar_sync(); 1097 1098 return rv; 1099 } 1100 1101 void 1102 pthread__unpark(pthread_queue_t *queue, pthread_t self, 1103 pthread_mutex_t *interlock) 1104 { 1105 pthread_t target; 1106 u_int max, nwaiters; 1107 1108 max = pthread__unpark_max; 1109 nwaiters = self->pt_nwaiters; 1110 target = PTQ_FIRST(queue); 1111 if (nwaiters == max) { 1112 /* Overflow. */ 1113 (void)_lwp_unpark_all(self->pt_waiters, nwaiters, 1114 __UNVOLATILE(&interlock->ptm_waiters)); 1115 nwaiters = 0; 1116 } 1117 target->pt_sleepobj = NULL; 1118 self->pt_waiters[nwaiters++] = target->pt_lid; 1119 PTQ_REMOVE(queue, target, pt_sleep); 1120 self->pt_nwaiters = nwaiters; 1121 pthread__mutex_deferwake(self, interlock); 1122 } 1123 1124 void 1125 pthread__unpark_all(pthread_queue_t *queue, pthread_t self, 1126 pthread_mutex_t *interlock) 1127 { 1128 pthread_t target; 1129 u_int max, nwaiters; 1130 1131 max = pthread__unpark_max; 1132 nwaiters = self->pt_nwaiters; 1133 PTQ_FOREACH(target, queue, pt_sleep) { 1134 if (nwaiters == max) { 1135 /* Overflow. */ 1136 (void)_lwp_unpark_all(self->pt_waiters, nwaiters, 1137 __UNVOLATILE(&interlock->ptm_waiters)); 1138 nwaiters = 0; 1139 } 1140 target->pt_sleepobj = NULL; 1141 self->pt_waiters[nwaiters++] = target->pt_lid; 1142 } 1143 self->pt_nwaiters = nwaiters; 1144 PTQ_INIT(queue); 1145 pthread__mutex_deferwake(self, interlock); 1146 } 1147 1148 #undef OOPS 1149 1150 /* 1151 * Allocate a stack for a thread, and set it up. It needs to be aligned, so 1152 * that a thread can find itself by its stack pointer. 1153 */ 1154 static int 1155 pthread__stackalloc(pthread_t *newt) 1156 { 1157 void *addr; 1158 1159 addr = mmap(NULL, pthread__stacksize, PROT_READ|PROT_WRITE, 1160 MAP_ANON|MAP_PRIVATE | MAP_ALIGNED(pthread__stacksize_lg), 1161 -1, (off_t)0); 1162 1163 if (addr == MAP_FAILED) 1164 return ENOMEM; 1165 1166 pthread__assert(((intptr_t)addr & pthread__stackmask) == 0); 1167 1168 return pthread__stackid_setup(addr, pthread__stacksize, newt); 1169 } 1170 1171 1172 /* 1173 * Set up the slightly special stack for the "initial" thread, which 1174 * runs on the normal system stack, and thus gets slightly different 1175 * treatment. 1176 */ 1177 static void 1178 pthread__initmain(pthread_t *newt) 1179 { 1180 struct rlimit slimit; 1181 size_t pagesize; 1182 pthread_t t; 1183 void *base; 1184 size_t size; 1185 int error, ret; 1186 char *value; 1187 1188 pagesize = (size_t)sysconf(_SC_PAGESIZE); 1189 pthread__stacksize = 0; 1190 ret = getrlimit(RLIMIT_STACK, &slimit); 1191 if (ret == -1) 1192 err(1, "Couldn't get stack resource consumption limits"); 1193 1194 value = pthread__getenv("PTHREAD_STACKSIZE"); 1195 if (value != NULL) { 1196 pthread__stacksize = atoi(value) * 1024; 1197 if (pthread__stacksize > slimit.rlim_cur) 1198 pthread__stacksize = (size_t)slimit.rlim_cur; 1199 } 1200 if (pthread__stacksize == 0) 1201 pthread__stacksize = (size_t)slimit.rlim_cur; 1202 if (pthread__stacksize < 4 * pagesize) 1203 errx(1, "Stacksize limit is too low, minimum %zd kbyte.", 1204 4 * pagesize / 1024); 1205 1206 pthread__stacksize_lg = -1; 1207 while (pthread__stacksize) { 1208 pthread__stacksize >>= 1; 1209 pthread__stacksize_lg++; 1210 } 1211 1212 pthread__stacksize = (1 << pthread__stacksize_lg); 1213 pthread__stackmask = pthread__stacksize - 1; 1214 pthread__threadmask = ~pthread__stackmask; 1215 1216 base = (void *)(pthread__sp() & pthread__threadmask); 1217 size = pthread__stacksize; 1218 1219 error = pthread__stackid_setup(base, size, &t); 1220 if (error) { 1221 /* XXX */ 1222 errx(2, "failed to setup main thread: error=%d", error); 1223 } 1224 1225 *newt = t; 1226 1227 #ifdef PTHREAD__HAVE_THREADREG 1228 /* Set up identity register. */ 1229 pthread__threadreg_set(t); 1230 #endif 1231 } 1232 1233 static int 1234 /*ARGSUSED*/ 1235 pthread__stackid_setup(void *base, size_t size, pthread_t *tp) 1236 { 1237 pthread_t t; 1238 void *redaddr; 1239 size_t pagesize; 1240 int ret; 1241 1242 t = base; 1243 pagesize = (size_t)sysconf(_SC_PAGESIZE); 1244 1245 /* 1246 * Put a pointer to the pthread in the bottom (but 1247 * redzone-protected section) of the stack. 1248 */ 1249 redaddr = STACK_SHRINK(STACK_MAX(base, size), pagesize); 1250 t->pt_stack.ss_size = size - 2 * pagesize; 1251 #ifdef __MACHINE_STACK_GROWS_UP 1252 t->pt_stack.ss_sp = (char *)(void *)base + pagesize; 1253 #else 1254 t->pt_stack.ss_sp = (char *)(void *)base + 2 * pagesize; 1255 #endif 1256 1257 /* Protect the next-to-bottom stack page as a red zone. */ 1258 ret = mprotect(redaddr, pagesize, PROT_NONE); 1259 if (ret == -1) { 1260 return errno; 1261 } 1262 *tp = t; 1263 return 0; 1264 } 1265 1266 #ifndef lint 1267 static int 1268 pthread__cmp(struct __pthread_st *a, struct __pthread_st *b) 1269 { 1270 return b - a; 1271 } 1272 RB_GENERATE_STATIC(__pthread__alltree, __pthread_st, pt_alltree, pthread__cmp) 1273 #endif 1274 1275 /* Because getenv() wants to use locks. */ 1276 char * 1277 pthread__getenv(const char *name) 1278 { 1279 extern char *__findenv(const char *, int *); 1280 int off; 1281 1282 return __findenv(name, &off); 1283 } 1284 1285 pthread_mutex_t * 1286 pthread__hashlock(volatile const void *p) 1287 { 1288 uintptr_t v; 1289 1290 v = (uintptr_t)p; 1291 return &hashlocks[((v >> 9) ^ (v >> 3)) & (NHASHLOCK - 1)].mutex; 1292 } 1293