1 /* $NetBSD: pthread.c,v 1.113 2009/10/03 23:49:50 christos 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 1.113 2009/10/03 23:49:50 christos 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 PTQ_FOREACH(newthread, &pthread__deadqueue, pt_deadq) { 357 /* Still running? */ 358 if (newthread->pt_lwpctl->lc_curcpu == 359 LWPCTL_CPU_EXITED || 360 (_lwp_kill(newthread->pt_lid, 0) == -1 && 361 errno == ESRCH)) 362 break; 363 } 364 if (newthread) 365 PTQ_REMOVE(&pthread__deadqueue, newthread, pt_deadq); 366 pthread_mutex_unlock(&pthread__deadqueue_lock); 367 } 368 369 /* 370 * If necessary set up a stack, allocate space for a pthread_st, 371 * and initialize it. 372 */ 373 if (newthread == NULL) { 374 ret = pthread__stackalloc(&newthread); 375 if (ret != 0) { 376 if (name) 377 free(name); 378 return ret; 379 } 380 381 /* This is used only when creating the thread. */ 382 _INITCONTEXT_U(&newthread->pt_uc); 383 #ifdef PTHREAD_MACHINE_HAS_ID_REGISTER 384 pthread__uc_id(&newthread->pt_uc) = newthread; 385 #endif 386 newthread->pt_uc.uc_stack = newthread->pt_stack; 387 newthread->pt_uc.uc_link = NULL; 388 389 /* Add to list of all threads. */ 390 pthread_rwlock_wrlock(&pthread__alltree_lock); 391 PTQ_INSERT_TAIL(&pthread__allqueue, newthread, pt_allq); 392 RB_INSERT(__pthread__alltree, &pthread__alltree, newthread); 393 pthread_rwlock_unlock(&pthread__alltree_lock); 394 395 /* Will be reset by the thread upon exit. */ 396 pthread__initthread(newthread); 397 } 398 399 /* 400 * Create the new LWP. 401 */ 402 pthread__scrubthread(newthread, name, nattr.pta_flags); 403 newthread->pt_func = startfunc; 404 newthread->pt_arg = arg; 405 _lwp_makecontext(&newthread->pt_uc, pthread__create_tramp, 406 newthread, newthread, newthread->pt_stack.ss_sp, 407 newthread->pt_stack.ss_size); 408 409 flag = LWP_DETACHED; 410 if ((newthread->pt_flags & PT_FLAG_SUSPENDED) != 0 || 411 (nattr.pta_flags & PT_FLAG_EXPLICIT_SCHED) != 0) 412 flag |= LWP_SUSPENDED; 413 ret = _lwp_create(&newthread->pt_uc, flag, &newthread->pt_lid); 414 if (ret != 0) { 415 free(name); 416 newthread->pt_state = PT_STATE_DEAD; 417 pthread_mutex_lock(&pthread__deadqueue_lock); 418 PTQ_INSERT_HEAD(&pthread__deadqueue, newthread, pt_deadq); 419 pthread_mutex_unlock(&pthread__deadqueue_lock); 420 return ret; 421 } 422 423 if ((nattr.pta_flags & PT_FLAG_EXPLICIT_SCHED) != 0) { 424 if (p != NULL) { 425 (void)pthread_setschedparam(newthread, p->ptap_policy, 426 &p->ptap_sp); 427 } 428 if ((newthread->pt_flags & PT_FLAG_SUSPENDED) == 0) { 429 (void)_lwp_continue(newthread->pt_lid); 430 } 431 } 432 433 *thread = newthread; 434 435 return 0; 436 } 437 438 439 static void 440 pthread__create_tramp(void *cookie) 441 { 442 pthread_t self; 443 void *retval; 444 445 self = cookie; 446 447 /* 448 * Throw away some stack in a feeble attempt to reduce cache 449 * thrash. May help for SMT processors. XXX We should not 450 * be allocating stacks on fixed 2MB boundaries. Needs a 451 * thread register or decent thread local storage. 452 * 453 * Note that we may race with the kernel in _lwp_create(), 454 * and so pt_lid can be unset at this point, but we don't 455 * care. 456 */ 457 (void)alloca(((unsigned)self->pt_lid & 7) << 8); 458 459 if (self->pt_name != NULL) { 460 pthread_mutex_lock(&self->pt_lock); 461 if (self->pt_name != NULL) 462 (void)_lwp_setname(0, self->pt_name); 463 pthread_mutex_unlock(&self->pt_lock); 464 } 465 466 if (_lwp_ctl(LWPCTL_FEATURE_CURCPU, &self->pt_lwpctl)) { 467 err(1, "_lwp_ctl"); 468 } 469 470 retval = (*self->pt_func)(self->pt_arg); 471 472 pthread_exit(retval); 473 474 /*NOTREACHED*/ 475 pthread__abort(); 476 } 477 478 int 479 pthread_suspend_np(pthread_t thread) 480 { 481 pthread_t self; 482 483 self = pthread__self(); 484 if (self == thread) { 485 return EDEADLK; 486 } 487 if (pthread__find(thread) != 0) 488 return ESRCH; 489 if (_lwp_suspend(thread->pt_lid) == 0) 490 return 0; 491 return errno; 492 } 493 494 int 495 pthread_resume_np(pthread_t thread) 496 { 497 498 if (pthread__find(thread) != 0) 499 return ESRCH; 500 if (_lwp_continue(thread->pt_lid) == 0) 501 return 0; 502 return errno; 503 } 504 505 void 506 pthread_exit(void *retval) 507 { 508 pthread_t self; 509 struct pt_clean_t *cleanup; 510 char *name; 511 512 self = pthread__self(); 513 514 /* Disable cancellability. */ 515 pthread_mutex_lock(&self->pt_lock); 516 self->pt_flags |= PT_FLAG_CS_DISABLED; 517 self->pt_cancel = 0; 518 519 /* Call any cancellation cleanup handlers */ 520 if (!PTQ_EMPTY(&self->pt_cleanup_stack)) { 521 pthread_mutex_unlock(&self->pt_lock); 522 while (!PTQ_EMPTY(&self->pt_cleanup_stack)) { 523 cleanup = PTQ_FIRST(&self->pt_cleanup_stack); 524 PTQ_REMOVE(&self->pt_cleanup_stack, cleanup, ptc_next); 525 (*cleanup->ptc_cleanup)(cleanup->ptc_arg); 526 } 527 pthread_mutex_lock(&self->pt_lock); 528 } 529 530 /* Perform cleanup of thread-specific data */ 531 pthread__destroy_tsd(self); 532 533 /* Signal our exit. */ 534 self->pt_exitval = retval; 535 if (self->pt_flags & PT_FLAG_DETACHED) { 536 self->pt_state = PT_STATE_DEAD; 537 name = self->pt_name; 538 self->pt_name = NULL; 539 pthread_mutex_unlock(&self->pt_lock); 540 if (name != NULL) 541 free(name); 542 pthread_mutex_lock(&pthread__deadqueue_lock); 543 PTQ_INSERT_TAIL(&pthread__deadqueue, self, pt_deadq); 544 pthread_mutex_unlock(&pthread__deadqueue_lock); 545 _lwp_exit(); 546 } else { 547 self->pt_state = PT_STATE_ZOMBIE; 548 pthread_cond_broadcast(&self->pt_joiners); 549 pthread_mutex_unlock(&self->pt_lock); 550 /* Note: name will be freed by the joiner. */ 551 _lwp_exit(); 552 } 553 554 /*NOTREACHED*/ 555 pthread__abort(); 556 exit(1); 557 } 558 559 560 int 561 pthread_join(pthread_t thread, void **valptr) 562 { 563 pthread_t self; 564 int error; 565 566 self = pthread__self(); 567 568 if (pthread__find(thread) != 0) 569 return ESRCH; 570 571 if (thread->pt_magic != PT_MAGIC) 572 return EINVAL; 573 574 if (thread == self) 575 return EDEADLK; 576 577 self->pt_droplock = &thread->pt_lock; 578 pthread_mutex_lock(&thread->pt_lock); 579 for (;;) { 580 if (thread->pt_state == PT_STATE_ZOMBIE) 581 break; 582 if (thread->pt_state == PT_STATE_DEAD) { 583 pthread_mutex_unlock(&thread->pt_lock); 584 self->pt_droplock = NULL; 585 return ESRCH; 586 } 587 if ((thread->pt_flags & PT_FLAG_DETACHED) != 0) { 588 pthread_mutex_unlock(&thread->pt_lock); 589 self->pt_droplock = NULL; 590 return EINVAL; 591 } 592 error = pthread_cond_wait(&thread->pt_joiners, 593 &thread->pt_lock); 594 if (error != 0) { 595 pthread__errorfunc(__FILE__, __LINE__, 596 __func__, "unexpected return from cond_wait()"); 597 } 598 599 } 600 pthread__testcancel(self); 601 if (valptr != NULL) 602 *valptr = thread->pt_exitval; 603 /* pthread__reap() will drop the lock. */ 604 pthread__reap(thread); 605 self->pt_droplock = NULL; 606 607 return 0; 608 } 609 610 static void 611 pthread__reap(pthread_t thread) 612 { 613 char *name; 614 615 name = thread->pt_name; 616 thread->pt_name = NULL; 617 thread->pt_state = PT_STATE_DEAD; 618 pthread_mutex_unlock(&thread->pt_lock); 619 620 pthread_mutex_lock(&pthread__deadqueue_lock); 621 PTQ_INSERT_HEAD(&pthread__deadqueue, thread, pt_deadq); 622 pthread_mutex_unlock(&pthread__deadqueue_lock); 623 624 if (name != NULL) 625 free(name); 626 } 627 628 int 629 pthread_equal(pthread_t t1, pthread_t t2) 630 { 631 632 /* Nothing special here. */ 633 return (t1 == t2); 634 } 635 636 637 int 638 pthread_detach(pthread_t thread) 639 { 640 641 if (pthread__find(thread) != 0) 642 return ESRCH; 643 644 if (thread->pt_magic != PT_MAGIC) 645 return EINVAL; 646 647 pthread_mutex_lock(&thread->pt_lock); 648 thread->pt_flags |= PT_FLAG_DETACHED; 649 if (thread->pt_state == PT_STATE_ZOMBIE) { 650 /* pthread__reap() will drop the lock. */ 651 pthread__reap(thread); 652 } else { 653 /* 654 * Not valid for threads to be waiting in 655 * pthread_join() (there are intractable 656 * sync issues from the application 657 * perspective), but give those threads 658 * a chance anyway. 659 */ 660 pthread_cond_broadcast(&thread->pt_joiners); 661 pthread_mutex_unlock(&thread->pt_lock); 662 } 663 664 return 0; 665 } 666 667 668 int 669 pthread_getname_np(pthread_t thread, char *name, size_t len) 670 { 671 672 if (pthread__find(thread) != 0) 673 return ESRCH; 674 675 if (thread->pt_magic != PT_MAGIC) 676 return EINVAL; 677 678 pthread_mutex_lock(&thread->pt_lock); 679 if (thread->pt_name == NULL) 680 name[0] = '\0'; 681 else 682 strlcpy(name, thread->pt_name, len); 683 pthread_mutex_unlock(&thread->pt_lock); 684 685 return 0; 686 } 687 688 689 int 690 pthread_setname_np(pthread_t thread, const char *name, void *arg) 691 { 692 char *oldname, *cp, newname[PTHREAD_MAX_NAMELEN_NP]; 693 int namelen; 694 695 if (pthread__find(thread) != 0) 696 return ESRCH; 697 698 if (thread->pt_magic != PT_MAGIC) 699 return EINVAL; 700 701 namelen = snprintf(newname, sizeof(newname), name, arg); 702 if (namelen >= PTHREAD_MAX_NAMELEN_NP) 703 return EINVAL; 704 705 cp = strdup(newname); 706 if (cp == NULL) 707 return ENOMEM; 708 709 pthread_mutex_lock(&thread->pt_lock); 710 oldname = thread->pt_name; 711 thread->pt_name = cp; 712 (void)_lwp_setname(thread->pt_lid, cp); 713 pthread_mutex_unlock(&thread->pt_lock); 714 715 if (oldname != NULL) 716 free(oldname); 717 718 return 0; 719 } 720 721 722 723 /* 724 * XXX There should be a way for applications to use the efficent 725 * inline version, but there are opacity/namespace issues. 726 */ 727 pthread_t 728 pthread_self(void) 729 { 730 731 return pthread__self(); 732 } 733 734 735 int 736 pthread_cancel(pthread_t thread) 737 { 738 739 if (pthread__find(thread) != 0) 740 return ESRCH; 741 pthread_mutex_lock(&thread->pt_lock); 742 thread->pt_flags |= PT_FLAG_CS_PENDING; 743 if ((thread->pt_flags & PT_FLAG_CS_DISABLED) == 0) { 744 thread->pt_cancel = 1; 745 pthread_mutex_unlock(&thread->pt_lock); 746 _lwp_wakeup(thread->pt_lid); 747 } else 748 pthread_mutex_unlock(&thread->pt_lock); 749 750 return 0; 751 } 752 753 754 int 755 pthread_setcancelstate(int state, int *oldstate) 756 { 757 pthread_t self; 758 int retval; 759 760 self = pthread__self(); 761 retval = 0; 762 763 pthread_mutex_lock(&self->pt_lock); 764 765 if (oldstate != NULL) { 766 if (self->pt_flags & PT_FLAG_CS_DISABLED) 767 *oldstate = PTHREAD_CANCEL_DISABLE; 768 else 769 *oldstate = PTHREAD_CANCEL_ENABLE; 770 } 771 772 if (state == PTHREAD_CANCEL_DISABLE) { 773 self->pt_flags |= PT_FLAG_CS_DISABLED; 774 if (self->pt_cancel) { 775 self->pt_flags |= PT_FLAG_CS_PENDING; 776 self->pt_cancel = 0; 777 } 778 } else if (state == PTHREAD_CANCEL_ENABLE) { 779 self->pt_flags &= ~PT_FLAG_CS_DISABLED; 780 /* 781 * If a cancellation was requested while cancellation 782 * was disabled, note that fact for future 783 * cancellation tests. 784 */ 785 if (self->pt_flags & PT_FLAG_CS_PENDING) { 786 self->pt_cancel = 1; 787 /* This is not a deferred cancellation point. */ 788 if (self->pt_flags & PT_FLAG_CS_ASYNC) { 789 pthread_mutex_unlock(&self->pt_lock); 790 pthread__cancelled(); 791 } 792 } 793 } else 794 retval = EINVAL; 795 796 pthread_mutex_unlock(&self->pt_lock); 797 798 return retval; 799 } 800 801 802 int 803 pthread_setcanceltype(int type, int *oldtype) 804 { 805 pthread_t self; 806 int retval; 807 808 self = pthread__self(); 809 retval = 0; 810 811 pthread_mutex_lock(&self->pt_lock); 812 813 if (oldtype != NULL) { 814 if (self->pt_flags & PT_FLAG_CS_ASYNC) 815 *oldtype = PTHREAD_CANCEL_ASYNCHRONOUS; 816 else 817 *oldtype = PTHREAD_CANCEL_DEFERRED; 818 } 819 820 if (type == PTHREAD_CANCEL_ASYNCHRONOUS) { 821 self->pt_flags |= PT_FLAG_CS_ASYNC; 822 if (self->pt_cancel) { 823 pthread_mutex_unlock(&self->pt_lock); 824 pthread__cancelled(); 825 } 826 } else if (type == PTHREAD_CANCEL_DEFERRED) 827 self->pt_flags &= ~PT_FLAG_CS_ASYNC; 828 else 829 retval = EINVAL; 830 831 pthread_mutex_unlock(&self->pt_lock); 832 833 return retval; 834 } 835 836 837 void 838 pthread_testcancel(void) 839 { 840 pthread_t self; 841 842 self = pthread__self(); 843 if (self->pt_cancel) 844 pthread__cancelled(); 845 } 846 847 848 /* 849 * POSIX requires that certain functions return an error rather than 850 * invoking undefined behavior even when handed completely bogus 851 * pthread_t values, e.g. stack garbage or (pthread_t)666. This 852 * utility routine searches the list of threads for the pthread_t 853 * value without dereferencing it. 854 */ 855 int 856 pthread__find(pthread_t id) 857 { 858 pthread_t target; 859 860 pthread_rwlock_rdlock(&pthread__alltree_lock); 861 /* LINTED */ 862 target = RB_FIND(__pthread__alltree, &pthread__alltree, id); 863 pthread_rwlock_unlock(&pthread__alltree_lock); 864 865 if (target == NULL || target->pt_state == PT_STATE_DEAD) 866 return ESRCH; 867 868 return 0; 869 } 870 871 872 void 873 pthread__testcancel(pthread_t self) 874 { 875 876 if (self->pt_cancel) 877 pthread__cancelled(); 878 } 879 880 881 void 882 pthread__cancelled(void) 883 { 884 pthread_mutex_t *droplock; 885 pthread_t self; 886 887 self = pthread__self(); 888 droplock = self->pt_droplock; 889 self->pt_droplock = NULL; 890 891 if (droplock != NULL && pthread_mutex_held_np(droplock)) 892 pthread_mutex_unlock(droplock); 893 894 pthread_exit(PTHREAD_CANCELED); 895 } 896 897 898 void 899 pthread__cleanup_push(void (*cleanup)(void *), void *arg, void *store) 900 { 901 pthread_t self; 902 struct pt_clean_t *entry; 903 904 self = pthread__self(); 905 entry = store; 906 entry->ptc_cleanup = cleanup; 907 entry->ptc_arg = arg; 908 PTQ_INSERT_HEAD(&self->pt_cleanup_stack, entry, ptc_next); 909 } 910 911 912 void 913 pthread__cleanup_pop(int ex, void *store) 914 { 915 pthread_t self; 916 struct pt_clean_t *entry; 917 918 self = pthread__self(); 919 entry = store; 920 921 PTQ_REMOVE(&self->pt_cleanup_stack, entry, ptc_next); 922 if (ex) 923 (*entry->ptc_cleanup)(entry->ptc_arg); 924 } 925 926 927 int * 928 pthread__errno(void) 929 { 930 pthread_t self; 931 932 self = pthread__self(); 933 934 return &(self->pt_errno); 935 } 936 937 ssize_t _sys_write(int, const void *, size_t); 938 939 void 940 pthread__assertfunc(const char *file, int line, const char *function, 941 const char *expr) 942 { 943 char buf[1024]; 944 int len; 945 946 /* 947 * snprintf should not acquire any locks, or we could 948 * end up deadlocked if the assert caller held locks. 949 */ 950 len = snprintf(buf, 1024, 951 "assertion \"%s\" failed: file \"%s\", line %d%s%s%s\n", 952 expr, file, line, 953 function ? ", function \"" : "", 954 function ? function : "", 955 function ? "\"" : ""); 956 957 _sys_write(STDERR_FILENO, buf, (size_t)len); 958 (void)kill(getpid(), SIGABRT); 959 960 _exit(1); 961 } 962 963 964 void 965 pthread__errorfunc(const char *file, int line, const char *function, 966 const char *msg) 967 { 968 char buf[1024]; 969 size_t len; 970 971 if (pthread__diagassert == 0) 972 return; 973 974 /* 975 * snprintf should not acquire any locks, or we could 976 * end up deadlocked if the assert caller held locks. 977 */ 978 len = snprintf(buf, 1024, 979 "%s: Error detected by libpthread: %s.\n" 980 "Detected by file \"%s\", line %d%s%s%s.\n" 981 "See pthread(3) for information.\n", 982 getprogname(), msg, file, line, 983 function ? ", function \"" : "", 984 function ? function : "", 985 function ? "\"" : ""); 986 987 if (pthread__diagassert & DIAGASSERT_STDERR) 988 _sys_write(STDERR_FILENO, buf, len); 989 990 if (pthread__diagassert & DIAGASSERT_SYSLOG) 991 syslog(LOG_DEBUG | LOG_USER, "%s", buf); 992 993 if (pthread__diagassert & DIAGASSERT_ABORT) { 994 (void)kill(getpid(), SIGABRT); 995 _exit(1); 996 } 997 } 998 999 /* 1000 * Thread park/unpark operations. The kernel operations are 1001 * modelled after a brief description from "Multithreading in 1002 * the Solaris Operating Environment": 1003 * 1004 * http://www.sun.com/software/whitepapers/solaris9/multithread.pdf 1005 */ 1006 1007 #define OOPS(msg) \ 1008 pthread__errorfunc(__FILE__, __LINE__, __func__, msg) 1009 1010 int 1011 pthread__park(pthread_t self, pthread_mutex_t *lock, 1012 pthread_queue_t *queue, const struct timespec *abstime, 1013 int cancelpt, const void *hint) 1014 { 1015 int rv, error; 1016 void *obj; 1017 1018 /* 1019 * For non-interlocked release of mutexes we need a store 1020 * barrier before incrementing pt_blocking away from zero. 1021 * This is provided by pthread_mutex_unlock(). 1022 */ 1023 self->pt_willpark = 1; 1024 pthread_mutex_unlock(lock); 1025 self->pt_willpark = 0; 1026 self->pt_blocking++; 1027 1028 /* 1029 * Wait until we are awoken by a pending unpark operation, 1030 * a signal, an unpark posted after we have gone asleep, 1031 * or an expired timeout. 1032 * 1033 * It is fine to test the value of pt_sleepobj without 1034 * holding any locks, because: 1035 * 1036 * o Only the blocking thread (this thread) ever sets them 1037 * to a non-NULL value. 1038 * 1039 * o Other threads may set them NULL, but if they do so they 1040 * must also make this thread return from _lwp_park. 1041 * 1042 * o _lwp_park, _lwp_unpark and _lwp_unpark_all are system 1043 * calls and all make use of spinlocks in the kernel. So 1044 * these system calls act as full memory barriers, and will 1045 * ensure that the calling CPU's store buffers are drained. 1046 * In combination with the spinlock release before unpark, 1047 * this means that modification of pt_sleepobj/onq by another 1048 * thread will become globally visible before that thread 1049 * schedules an unpark operation on this thread. 1050 * 1051 * Note: the test in the while() statement dodges the park op if 1052 * we have already been awoken, unless there is another thread to 1053 * awaken. This saves a syscall - if we were already awakened, 1054 * the next call to _lwp_park() would need to return early in order 1055 * to eat the previous wakeup. 1056 */ 1057 rv = 0; 1058 do { 1059 /* 1060 * If we deferred unparking a thread, arrange to 1061 * have _lwp_park() restart it before blocking. 1062 */ 1063 error = _lwp_park(abstime, self->pt_unpark, hint, hint); 1064 self->pt_unpark = 0; 1065 if (error != 0) { 1066 switch (rv = errno) { 1067 case EINTR: 1068 case EALREADY: 1069 rv = 0; 1070 break; 1071 case ETIMEDOUT: 1072 break; 1073 default: 1074 OOPS("_lwp_park failed"); 1075 break; 1076 } 1077 } 1078 /* Check for cancellation. */ 1079 if (cancelpt && self->pt_cancel) 1080 rv = EINTR; 1081 } while (self->pt_sleepobj != NULL && rv == 0); 1082 1083 /* 1084 * If we have been awoken early but are still on the queue, 1085 * then remove ourself. Again, it's safe to do the test 1086 * without holding any locks. 1087 */ 1088 if (__predict_false(self->pt_sleepobj != NULL)) { 1089 pthread_mutex_lock(lock); 1090 if ((obj = self->pt_sleepobj) != NULL) { 1091 PTQ_REMOVE(queue, self, pt_sleep); 1092 self->pt_sleepobj = NULL; 1093 if (obj != NULL && self->pt_early != NULL) 1094 (*self->pt_early)(obj); 1095 } 1096 pthread_mutex_unlock(lock); 1097 } 1098 self->pt_early = NULL; 1099 self->pt_blocking--; 1100 membar_sync(); 1101 1102 return rv; 1103 } 1104 1105 void 1106 pthread__unpark(pthread_queue_t *queue, pthread_t self, 1107 pthread_mutex_t *interlock) 1108 { 1109 pthread_t target; 1110 u_int max; 1111 size_t nwaiters; 1112 1113 max = pthread__unpark_max; 1114 nwaiters = self->pt_nwaiters; 1115 target = PTQ_FIRST(queue); 1116 if (nwaiters == max) { 1117 /* Overflow. */ 1118 (void)_lwp_unpark_all(self->pt_waiters, nwaiters, 1119 __UNVOLATILE(&interlock->ptm_waiters)); 1120 nwaiters = 0; 1121 } 1122 target->pt_sleepobj = NULL; 1123 self->pt_waiters[nwaiters++] = target->pt_lid; 1124 PTQ_REMOVE(queue, target, pt_sleep); 1125 self->pt_nwaiters = nwaiters; 1126 pthread__mutex_deferwake(self, interlock); 1127 } 1128 1129 void 1130 pthread__unpark_all(pthread_queue_t *queue, pthread_t self, 1131 pthread_mutex_t *interlock) 1132 { 1133 pthread_t target; 1134 u_int max; 1135 size_t nwaiters; 1136 1137 max = pthread__unpark_max; 1138 nwaiters = self->pt_nwaiters; 1139 PTQ_FOREACH(target, queue, pt_sleep) { 1140 if (nwaiters == max) { 1141 /* Overflow. */ 1142 (void)_lwp_unpark_all(self->pt_waiters, nwaiters, 1143 __UNVOLATILE(&interlock->ptm_waiters)); 1144 nwaiters = 0; 1145 } 1146 target->pt_sleepobj = NULL; 1147 self->pt_waiters[nwaiters++] = target->pt_lid; 1148 } 1149 self->pt_nwaiters = nwaiters; 1150 PTQ_INIT(queue); 1151 pthread__mutex_deferwake(self, interlock); 1152 } 1153 1154 #undef OOPS 1155 1156 /* 1157 * Allocate a stack for a thread, and set it up. It needs to be aligned, so 1158 * that a thread can find itself by its stack pointer. 1159 */ 1160 static int 1161 pthread__stackalloc(pthread_t *newt) 1162 { 1163 void *addr; 1164 1165 addr = mmap(NULL, pthread__stacksize, PROT_READ|PROT_WRITE, 1166 MAP_ANON|MAP_PRIVATE | MAP_ALIGNED(pthread__stacksize_lg), 1167 -1, (off_t)0); 1168 1169 if (addr == MAP_FAILED) 1170 return ENOMEM; 1171 1172 pthread__assert(((intptr_t)addr & pthread__stackmask) == 0); 1173 1174 return pthread__stackid_setup(addr, pthread__stacksize, newt); 1175 } 1176 1177 1178 /* 1179 * Set up the slightly special stack for the "initial" thread, which 1180 * runs on the normal system stack, and thus gets slightly different 1181 * treatment. 1182 */ 1183 static void 1184 pthread__initmain(pthread_t *newt) 1185 { 1186 struct rlimit slimit; 1187 size_t pagesize; 1188 pthread_t t; 1189 void *base; 1190 size_t size; 1191 int error, ret; 1192 char *value; 1193 1194 pagesize = (size_t)sysconf(_SC_PAGESIZE); 1195 pthread__stacksize = 0; 1196 ret = getrlimit(RLIMIT_STACK, &slimit); 1197 if (ret == -1) 1198 err(1, "Couldn't get stack resource consumption limits"); 1199 1200 value = pthread__getenv("PTHREAD_STACKSIZE"); 1201 if (value != NULL) { 1202 pthread__stacksize = atoi(value) * 1024; 1203 if (pthread__stacksize > slimit.rlim_cur) 1204 pthread__stacksize = (size_t)slimit.rlim_cur; 1205 } 1206 if (pthread__stacksize == 0) 1207 pthread__stacksize = (size_t)slimit.rlim_cur; 1208 if (pthread__stacksize < 4 * pagesize) 1209 errx(1, "Stacksize limit is too low, minimum %zd kbyte.", 1210 4 * pagesize / 1024); 1211 1212 pthread__stacksize_lg = -1; 1213 while (pthread__stacksize) { 1214 pthread__stacksize >>= 1; 1215 pthread__stacksize_lg++; 1216 } 1217 1218 pthread__stacksize = (1 << pthread__stacksize_lg); 1219 pthread__stackmask = pthread__stacksize - 1; 1220 pthread__threadmask = ~pthread__stackmask; 1221 1222 base = (void *)(pthread__sp() & pthread__threadmask); 1223 size = pthread__stacksize; 1224 1225 error = pthread__stackid_setup(base, size, &t); 1226 if (error) { 1227 /* XXX */ 1228 errx(2, "failed to setup main thread: error=%d", error); 1229 } 1230 1231 *newt = t; 1232 1233 /* Set up identity register. */ 1234 (void)_lwp_setprivate(t); 1235 } 1236 1237 static int 1238 /*ARGSUSED*/ 1239 pthread__stackid_setup(void *base, size_t size, pthread_t *tp) 1240 { 1241 pthread_t t; 1242 void *redaddr; 1243 size_t pagesize; 1244 int ret; 1245 1246 t = base; 1247 pagesize = (size_t)sysconf(_SC_PAGESIZE); 1248 1249 /* 1250 * Put a pointer to the pthread in the bottom (but 1251 * redzone-protected section) of the stack. 1252 */ 1253 redaddr = STACK_SHRINK(STACK_MAX(base, size), pagesize); 1254 t->pt_stack.ss_size = size - 2 * pagesize; 1255 #ifdef __MACHINE_STACK_GROWS_UP 1256 t->pt_stack.ss_sp = (char *)(void *)base + pagesize; 1257 #else 1258 t->pt_stack.ss_sp = (char *)(void *)base + 2 * pagesize; 1259 #endif 1260 1261 /* Protect the next-to-bottom stack page as a red zone. */ 1262 ret = mprotect(redaddr, pagesize, PROT_NONE); 1263 if (ret == -1) { 1264 return errno; 1265 } 1266 *tp = t; 1267 return 0; 1268 } 1269 1270 #ifndef lint 1271 static int 1272 pthread__cmp(struct __pthread_st *a, struct __pthread_st *b) 1273 { 1274 1275 if ((uintptr_t)a < (uintptr_t)b) 1276 return (-1); 1277 else if (a == b) 1278 return 0; 1279 else 1280 return 1; 1281 } 1282 RB_GENERATE_STATIC(__pthread__alltree, __pthread_st, pt_alltree, pthread__cmp) 1283 #endif 1284 1285 /* Because getenv() wants to use locks. */ 1286 char * 1287 pthread__getenv(const char *name) 1288 { 1289 extern char *__findenv(const char *, int *); 1290 int off; 1291 1292 return __findenv(name, &off); 1293 } 1294 1295 pthread_mutex_t * 1296 pthread__hashlock(volatile const void *p) 1297 { 1298 uintptr_t v; 1299 1300 v = (uintptr_t)p; 1301 return &hashlocks[((v >> 9) ^ (v >> 3)) & (NHASHLOCK - 1)].mutex; 1302 } 1303 1304 int 1305 pthread__checkpri(int pri) 1306 { 1307 static int havepri; 1308 static long min, max; 1309 1310 if (!havepri) { 1311 min = sysconf(_SC_SCHED_PRI_MIN); 1312 max = sysconf(_SC_SCHED_PRI_MAX); 1313 havepri = 1; 1314 } 1315 return (pri < min || pri > max) ? EINVAL : 0; 1316 } 1317