1 /* $NetBSD: pthread.c,v 1.128 2012/03/08 16:40:45 joerg 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 1.128 2012/03/08 16:40:45 joerg Exp $"); 34 35 #define __EXPOSE_STACK 1 36 37 #include <sys/param.h> 38 #include <sys/exec_elf.h> 39 #include <sys/mman.h> 40 #include <sys/sysctl.h> 41 #include <sys/lwpctl.h> 42 #include <sys/tls.h> 43 44 #include <assert.h> 45 #include <dlfcn.h> 46 #include <err.h> 47 #include <errno.h> 48 #include <lwp.h> 49 #include <signal.h> 50 #include <stdio.h> 51 #include <stdlib.h> 52 #include <string.h> 53 #include <syslog.h> 54 #include <ucontext.h> 55 #include <unistd.h> 56 #include <sched.h> 57 58 #include "pthread.h" 59 #include "pthread_int.h" 60 61 pthread_rwlock_t pthread__alltree_lock = PTHREAD_RWLOCK_INITIALIZER; 62 RB_HEAD(__pthread__alltree, __pthread_st) pthread__alltree; 63 64 #ifndef lint 65 static int pthread__cmp(struct __pthread_st *, struct __pthread_st *); 66 RB_PROTOTYPE_STATIC(__pthread__alltree, __pthread_st, pt_alltree, pthread__cmp) 67 #endif 68 69 static void pthread__create_tramp(void *); 70 static void pthread__initthread(pthread_t); 71 static void pthread__scrubthread(pthread_t, char *, int); 72 static void pthread__initmain(pthread_t *); 73 static void pthread__fork_callback(void); 74 static void pthread__reap(pthread_t); 75 static void pthread__child_callback(void); 76 static void pthread__start(void); 77 78 void pthread__init(void); 79 80 int pthread__started; 81 pthread_mutex_t pthread__deadqueue_lock = PTHREAD_MUTEX_INITIALIZER; 82 pthread_queue_t pthread__deadqueue; 83 pthread_queue_t pthread__allqueue; 84 85 static pthread_attr_t pthread_default_attr; 86 static lwpctl_t pthread__dummy_lwpctl = { .lc_curcpu = LWPCTL_CPU_NONE }; 87 static pthread_t pthread__first; 88 89 enum { 90 DIAGASSERT_ABORT = 1<<0, 91 DIAGASSERT_STDERR = 1<<1, 92 DIAGASSERT_SYSLOG = 1<<2 93 }; 94 95 static int pthread__diagassert; 96 97 int pthread__concurrency; 98 int pthread__nspins; 99 int pthread__unpark_max = PTHREAD__UNPARK_MAX; 100 int pthread__dbg; /* set by libpthread_dbg if active */ 101 102 /* 103 * We have to initialize the pthread_stack* variables here because 104 * mutexes are used before pthread_init() and thus pthread__initmain() 105 * are called. Since mutexes only save the stack pointer and not a 106 * pointer to the thread data, it is safe to change the mapping from 107 * stack pointer to thread data afterwards. 108 */ 109 size_t pthread__stacksize; 110 size_t pthread__pagesize; 111 static struct __pthread_st pthread__main; 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 pthread__pagesize = (size_t)sysconf(_SC_PAGESIZE); 162 163 mib[0] = CTL_HW; 164 mib[1] = HW_NCPU; 165 166 len = sizeof(pthread__concurrency); 167 if (sysctl(mib, 2, &pthread__concurrency, &len, NULL, 0) == -1) 168 err(1, "sysctl(hw.ncpu"); 169 170 mib[0] = CTL_KERN; 171 mib[1] = KERN_OSREV; 172 173 /* Initialize locks first; they're needed elsewhere. */ 174 pthread__lockprim_init(); 175 for (i = 0; i < NHASHLOCK; i++) { 176 pthread_mutex_init(&hashlocks[i].mutex, NULL); 177 } 178 179 /* Fetch parameters. */ 180 i = (int)_lwp_unpark_all(NULL, 0, NULL); 181 if (i == -1) 182 err(1, "_lwp_unpark_all"); 183 if (i < pthread__unpark_max) 184 pthread__unpark_max = i; 185 186 /* Basic data structure setup */ 187 pthread_attr_init(&pthread_default_attr); 188 PTQ_INIT(&pthread__allqueue); 189 PTQ_INIT(&pthread__deadqueue); 190 RB_INIT(&pthread__alltree); 191 192 /* Create the thread structure corresponding to main() */ 193 pthread__initmain(&first); 194 pthread__initthread(first); 195 pthread__scrubthread(first, NULL, 0); 196 197 first->pt_lid = _lwp_self(); 198 PTQ_INSERT_HEAD(&pthread__allqueue, first, pt_allq); 199 RB_INSERT(__pthread__alltree, &pthread__alltree, first); 200 201 if (_lwp_ctl(LWPCTL_FEATURE_CURCPU, &first->pt_lwpctl) != 0) { 202 err(1, "_lwp_ctl"); 203 } 204 205 /* Start subsystems */ 206 PTHREAD_MD_INIT 207 208 for (p = pthread__getenv("PTHREAD_DIAGASSERT"); p && *p; p++) { 209 switch (*p) { 210 case 'a': 211 pthread__diagassert |= DIAGASSERT_ABORT; 212 break; 213 case 'A': 214 pthread__diagassert &= ~DIAGASSERT_ABORT; 215 break; 216 case 'e': 217 pthread__diagassert |= DIAGASSERT_STDERR; 218 break; 219 case 'E': 220 pthread__diagassert &= ~DIAGASSERT_STDERR; 221 break; 222 case 'l': 223 pthread__diagassert |= DIAGASSERT_SYSLOG; 224 break; 225 case 'L': 226 pthread__diagassert &= ~DIAGASSERT_SYSLOG; 227 break; 228 } 229 } 230 231 /* Tell libc that we're here and it should role-play accordingly. */ 232 pthread__first = first; 233 pthread_atfork(NULL, NULL, pthread__fork_callback); 234 __isthreaded = 1; 235 } 236 237 static void 238 pthread__fork_callback(void) 239 { 240 struct __pthread_st *self; 241 242 /* lwpctl state is not copied across fork. */ 243 if (_lwp_ctl(LWPCTL_FEATURE_CURCPU, &pthread__first->pt_lwpctl)) { 244 err(1, "_lwp_ctl"); 245 } 246 self = pthread__self(); 247 self->pt_lid = _lwp_self(); 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 static int 320 pthread__newstack(pthread_t newthread, const pthread_attr_t *attr) 321 { 322 void *stackbase, *redzone; 323 size_t stacksize; 324 bool mapped_stack = false; 325 326 if (attr != NULL) { 327 pthread_attr_getstack(attr, &stackbase, &stacksize); 328 } else { 329 stackbase = NULL; 330 stacksize = 0; 331 } 332 if (stacksize == 0) 333 stacksize = pthread__stacksize; 334 335 if (stackbase == NULL) { 336 stackbase = mmap(NULL, stacksize, 337 PROT_READ|PROT_WRITE, MAP_ANON|MAP_PRIVATE, -1, (off_t)0); 338 if (stackbase == MAP_FAILED) 339 return ENOMEM; 340 mapped_stack = true; 341 } 342 newthread->pt_stack.ss_size = pthread__stacksize - pthread__pagesize; 343 newthread->pt_stack.ss_sp = stackbase; 344 #ifdef __MACHINE_STACK_GROWS_UP 345 redzone = (char *)stackbase + newthread->pt_stack.ss_size; 346 #else 347 redzone = (char *)stackbase; 348 #endif 349 if (mprotect(redzone, pthread__pagesize, PROT_NONE) == -1) { 350 if (mapped_stack) 351 munmap(stackbase, pthread__stacksize); 352 return EPERM; 353 } 354 return 0; 355 } 356 357 int 358 pthread_create(pthread_t *thread, const pthread_attr_t *attr, 359 void *(*startfunc)(void *), void *arg) 360 { 361 pthread_t newthread; 362 pthread_attr_t nattr; 363 struct pthread_attr_private *p; 364 char * volatile name; 365 unsigned long flag; 366 void *private_area; 367 int ret; 368 369 /* 370 * It's okay to check this without a lock because there can 371 * only be one thread before it becomes true. 372 */ 373 if (pthread__started == 0) { 374 pthread__start(); 375 pthread__started = 1; 376 } 377 378 if (attr == NULL) 379 nattr = pthread_default_attr; 380 else if (attr->pta_magic == PT_ATTR_MAGIC) 381 nattr = *attr; 382 else 383 return EINVAL; 384 385 /* Fetch misc. attributes from the attr structure. */ 386 name = NULL; 387 if ((p = nattr.pta_private) != NULL) 388 if (p->ptap_name[0] != '\0') 389 if ((name = strdup(p->ptap_name)) == NULL) 390 return ENOMEM; 391 392 newthread = NULL; 393 394 /* 395 * Try to reclaim a dead thread. 396 */ 397 if (!PTQ_EMPTY(&pthread__deadqueue)) { 398 pthread_mutex_lock(&pthread__deadqueue_lock); 399 PTQ_FOREACH(newthread, &pthread__deadqueue, pt_deadq) { 400 /* Still running? */ 401 if (newthread->pt_lwpctl->lc_curcpu == 402 LWPCTL_CPU_EXITED || 403 (_lwp_kill(newthread->pt_lid, 0) == -1 && 404 errno == ESRCH)) 405 break; 406 } 407 if (newthread) 408 PTQ_REMOVE(&pthread__deadqueue, newthread, pt_deadq); 409 pthread_mutex_unlock(&pthread__deadqueue_lock); 410 #if defined(__HAVE_TLS_VARIANT_I) || defined(__HAVE_TLS_VARIANT_II) 411 if (newthread && newthread->pt_tls) { 412 _rtld_tls_free(newthread->pt_tls); 413 newthread->pt_tls = NULL; 414 } 415 #endif 416 } 417 418 /* 419 * If necessary set up a stack, allocate space for a pthread_st, 420 * and initialize it. 421 */ 422 if (newthread == NULL) { 423 newthread = malloc(sizeof(*newthread)); 424 if (newthread == NULL) { 425 free(name); 426 return ENOMEM; 427 } 428 429 if (pthread__newstack(newthread, attr)) { 430 free(newthread); 431 free(name); 432 return ENOMEM; 433 } 434 435 /* This is used only when creating the thread. */ 436 _INITCONTEXT_U(&newthread->pt_uc); 437 newthread->pt_uc.uc_stack = newthread->pt_stack; 438 newthread->pt_uc.uc_link = NULL; 439 #if defined(__HAVE_TLS_VARIANT_I) || defined(__HAVE_TLS_VARIANT_II) 440 newthread->pt_tls = NULL; 441 #endif 442 443 /* Add to list of all threads. */ 444 pthread_rwlock_wrlock(&pthread__alltree_lock); 445 PTQ_INSERT_TAIL(&pthread__allqueue, newthread, pt_allq); 446 RB_INSERT(__pthread__alltree, &pthread__alltree, newthread); 447 pthread_rwlock_unlock(&pthread__alltree_lock); 448 449 /* Will be reset by the thread upon exit. */ 450 pthread__initthread(newthread); 451 } 452 453 /* 454 * Create the new LWP. 455 */ 456 pthread__scrubthread(newthread, name, nattr.pta_flags); 457 newthread->pt_func = startfunc; 458 newthread->pt_arg = arg; 459 #if defined(__HAVE_TLS_VARIANT_I) || defined(__HAVE_TLS_VARIANT_II) 460 private_area = newthread->pt_tls = _rtld_tls_allocate(); 461 newthread->pt_tls->tcb_pthread = newthread; 462 #else 463 private_area = newthread; 464 #endif 465 466 _lwp_makecontext(&newthread->pt_uc, pthread__create_tramp, 467 newthread, private_area, newthread->pt_stack.ss_sp, 468 newthread->pt_stack.ss_size); 469 470 flag = LWP_DETACHED; 471 if ((newthread->pt_flags & PT_FLAG_SUSPENDED) != 0 || 472 (nattr.pta_flags & PT_FLAG_EXPLICIT_SCHED) != 0) 473 flag |= LWP_SUSPENDED; 474 ret = _lwp_create(&newthread->pt_uc, flag, &newthread->pt_lid); 475 if (ret != 0) { 476 pthread_mutex_lock(&newthread->pt_lock); 477 /* Will unlock and free name. */ 478 pthread__reap(newthread); 479 return ret; 480 } 481 482 if ((nattr.pta_flags & PT_FLAG_EXPLICIT_SCHED) != 0) { 483 if (p != NULL) { 484 (void)pthread_setschedparam(newthread, p->ptap_policy, 485 &p->ptap_sp); 486 } 487 if ((newthread->pt_flags & PT_FLAG_SUSPENDED) == 0) { 488 (void)_lwp_continue(newthread->pt_lid); 489 } 490 } 491 492 *thread = newthread; 493 494 return 0; 495 } 496 497 498 __dead static void 499 pthread__create_tramp(void *cookie) 500 { 501 pthread_t self; 502 void *retval; 503 504 self = cookie; 505 506 /* 507 * Throw away some stack in a feeble attempt to reduce cache 508 * thrash. May help for SMT processors. XXX We should not 509 * be allocating stacks on fixed 2MB boundaries. Needs a 510 * thread register or decent thread local storage. 511 * 512 * Note that we may race with the kernel in _lwp_create(), 513 * and so pt_lid can be unset at this point, but we don't 514 * care. 515 */ 516 (void)alloca(((unsigned)self->pt_lid & 7) << 8); 517 518 if (self->pt_name != NULL) { 519 pthread_mutex_lock(&self->pt_lock); 520 if (self->pt_name != NULL) 521 (void)_lwp_setname(0, self->pt_name); 522 pthread_mutex_unlock(&self->pt_lock); 523 } 524 525 if (_lwp_ctl(LWPCTL_FEATURE_CURCPU, &self->pt_lwpctl)) { 526 err(1, "_lwp_ctl"); 527 } 528 529 retval = (*self->pt_func)(self->pt_arg); 530 531 pthread_exit(retval); 532 533 /*NOTREACHED*/ 534 pthread__abort(); 535 } 536 537 int 538 pthread_suspend_np(pthread_t thread) 539 { 540 pthread_t self; 541 542 self = pthread__self(); 543 if (self == thread) { 544 return EDEADLK; 545 } 546 if (pthread__find(thread) != 0) 547 return ESRCH; 548 if (_lwp_suspend(thread->pt_lid) == 0) 549 return 0; 550 return errno; 551 } 552 553 int 554 pthread_resume_np(pthread_t thread) 555 { 556 557 if (pthread__find(thread) != 0) 558 return ESRCH; 559 if (_lwp_continue(thread->pt_lid) == 0) 560 return 0; 561 return errno; 562 } 563 564 void 565 pthread_exit(void *retval) 566 { 567 pthread_t self; 568 struct pt_clean_t *cleanup; 569 char *name; 570 571 self = pthread__self(); 572 573 /* Disable cancellability. */ 574 pthread_mutex_lock(&self->pt_lock); 575 self->pt_flags |= PT_FLAG_CS_DISABLED; 576 self->pt_cancel = 0; 577 578 /* Call any cancellation cleanup handlers */ 579 if (!PTQ_EMPTY(&self->pt_cleanup_stack)) { 580 pthread_mutex_unlock(&self->pt_lock); 581 while (!PTQ_EMPTY(&self->pt_cleanup_stack)) { 582 cleanup = PTQ_FIRST(&self->pt_cleanup_stack); 583 PTQ_REMOVE(&self->pt_cleanup_stack, cleanup, ptc_next); 584 (*cleanup->ptc_cleanup)(cleanup->ptc_arg); 585 } 586 pthread_mutex_lock(&self->pt_lock); 587 } 588 589 /* Perform cleanup of thread-specific data */ 590 pthread__destroy_tsd(self); 591 592 /* Signal our exit. */ 593 self->pt_exitval = retval; 594 if (self->pt_flags & PT_FLAG_DETACHED) { 595 self->pt_state = PT_STATE_DEAD; 596 name = self->pt_name; 597 self->pt_name = NULL; 598 pthread_mutex_unlock(&self->pt_lock); 599 if (name != NULL) 600 free(name); 601 pthread_mutex_lock(&pthread__deadqueue_lock); 602 PTQ_INSERT_TAIL(&pthread__deadqueue, self, pt_deadq); 603 pthread_mutex_unlock(&pthread__deadqueue_lock); 604 _lwp_exit(); 605 } else { 606 self->pt_state = PT_STATE_ZOMBIE; 607 pthread_cond_broadcast(&self->pt_joiners); 608 pthread_mutex_unlock(&self->pt_lock); 609 /* Note: name will be freed by the joiner. */ 610 _lwp_exit(); 611 } 612 613 /*NOTREACHED*/ 614 pthread__abort(); 615 exit(1); 616 } 617 618 619 int 620 pthread_join(pthread_t thread, void **valptr) 621 { 622 pthread_t self; 623 int error; 624 625 self = pthread__self(); 626 627 if (pthread__find(thread) != 0) 628 return ESRCH; 629 630 if (thread->pt_magic != PT_MAGIC) 631 return EINVAL; 632 633 if (thread == self) 634 return EDEADLK; 635 636 self->pt_droplock = &thread->pt_lock; 637 pthread_mutex_lock(&thread->pt_lock); 638 for (;;) { 639 if (thread->pt_state == PT_STATE_ZOMBIE) 640 break; 641 if (thread->pt_state == PT_STATE_DEAD) { 642 pthread_mutex_unlock(&thread->pt_lock); 643 self->pt_droplock = NULL; 644 return ESRCH; 645 } 646 if ((thread->pt_flags & PT_FLAG_DETACHED) != 0) { 647 pthread_mutex_unlock(&thread->pt_lock); 648 self->pt_droplock = NULL; 649 return EINVAL; 650 } 651 error = pthread_cond_wait(&thread->pt_joiners, 652 &thread->pt_lock); 653 if (error != 0) { 654 pthread__errorfunc(__FILE__, __LINE__, 655 __func__, "unexpected return from cond_wait()"); 656 } 657 658 } 659 pthread__testcancel(self); 660 if (valptr != NULL) 661 *valptr = thread->pt_exitval; 662 /* pthread__reap() will drop the lock. */ 663 pthread__reap(thread); 664 self->pt_droplock = NULL; 665 666 return 0; 667 } 668 669 static void 670 pthread__reap(pthread_t thread) 671 { 672 char *name; 673 674 name = thread->pt_name; 675 thread->pt_name = NULL; 676 thread->pt_state = PT_STATE_DEAD; 677 pthread_mutex_unlock(&thread->pt_lock); 678 679 pthread_mutex_lock(&pthread__deadqueue_lock); 680 PTQ_INSERT_HEAD(&pthread__deadqueue, thread, pt_deadq); 681 pthread_mutex_unlock(&pthread__deadqueue_lock); 682 683 if (name != NULL) 684 free(name); 685 } 686 687 int 688 pthread_equal(pthread_t t1, pthread_t t2) 689 { 690 691 /* Nothing special here. */ 692 return (t1 == t2); 693 } 694 695 696 int 697 pthread_detach(pthread_t thread) 698 { 699 700 if (pthread__find(thread) != 0) 701 return ESRCH; 702 703 if (thread->pt_magic != PT_MAGIC) 704 return EINVAL; 705 706 pthread_mutex_lock(&thread->pt_lock); 707 thread->pt_flags |= PT_FLAG_DETACHED; 708 if (thread->pt_state == PT_STATE_ZOMBIE) { 709 /* pthread__reap() will drop the lock. */ 710 pthread__reap(thread); 711 } else { 712 /* 713 * Not valid for threads to be waiting in 714 * pthread_join() (there are intractable 715 * sync issues from the application 716 * perspective), but give those threads 717 * a chance anyway. 718 */ 719 pthread_cond_broadcast(&thread->pt_joiners); 720 pthread_mutex_unlock(&thread->pt_lock); 721 } 722 723 return 0; 724 } 725 726 727 int 728 pthread_getname_np(pthread_t thread, char *name, size_t len) 729 { 730 731 if (pthread__find(thread) != 0) 732 return ESRCH; 733 734 if (thread->pt_magic != PT_MAGIC) 735 return EINVAL; 736 737 pthread_mutex_lock(&thread->pt_lock); 738 if (thread->pt_name == NULL) 739 name[0] = '\0'; 740 else 741 strlcpy(name, thread->pt_name, len); 742 pthread_mutex_unlock(&thread->pt_lock); 743 744 return 0; 745 } 746 747 748 int 749 pthread_setname_np(pthread_t thread, const char *name, void *arg) 750 { 751 char *oldname, *cp, newname[PTHREAD_MAX_NAMELEN_NP]; 752 int namelen; 753 754 if (pthread__find(thread) != 0) 755 return ESRCH; 756 757 if (thread->pt_magic != PT_MAGIC) 758 return EINVAL; 759 760 namelen = snprintf(newname, sizeof(newname), name, arg); 761 if (namelen >= PTHREAD_MAX_NAMELEN_NP) 762 return EINVAL; 763 764 cp = strdup(newname); 765 if (cp == NULL) 766 return ENOMEM; 767 768 pthread_mutex_lock(&thread->pt_lock); 769 oldname = thread->pt_name; 770 thread->pt_name = cp; 771 (void)_lwp_setname(thread->pt_lid, cp); 772 pthread_mutex_unlock(&thread->pt_lock); 773 774 if (oldname != NULL) 775 free(oldname); 776 777 return 0; 778 } 779 780 781 782 /* 783 * XXX There should be a way for applications to use the efficent 784 * inline version, but there are opacity/namespace issues. 785 */ 786 pthread_t 787 pthread_self(void) 788 { 789 790 return pthread__self(); 791 } 792 793 794 int 795 pthread_cancel(pthread_t thread) 796 { 797 798 if (pthread__find(thread) != 0) 799 return ESRCH; 800 pthread_mutex_lock(&thread->pt_lock); 801 thread->pt_flags |= PT_FLAG_CS_PENDING; 802 if ((thread->pt_flags & PT_FLAG_CS_DISABLED) == 0) { 803 thread->pt_cancel = 1; 804 pthread_mutex_unlock(&thread->pt_lock); 805 _lwp_wakeup(thread->pt_lid); 806 } else 807 pthread_mutex_unlock(&thread->pt_lock); 808 809 return 0; 810 } 811 812 813 int 814 pthread_setcancelstate(int state, int *oldstate) 815 { 816 pthread_t self; 817 int retval; 818 819 self = pthread__self(); 820 retval = 0; 821 822 pthread_mutex_lock(&self->pt_lock); 823 824 if (oldstate != NULL) { 825 if (self->pt_flags & PT_FLAG_CS_DISABLED) 826 *oldstate = PTHREAD_CANCEL_DISABLE; 827 else 828 *oldstate = PTHREAD_CANCEL_ENABLE; 829 } 830 831 if (state == PTHREAD_CANCEL_DISABLE) { 832 self->pt_flags |= PT_FLAG_CS_DISABLED; 833 if (self->pt_cancel) { 834 self->pt_flags |= PT_FLAG_CS_PENDING; 835 self->pt_cancel = 0; 836 } 837 } else if (state == PTHREAD_CANCEL_ENABLE) { 838 self->pt_flags &= ~PT_FLAG_CS_DISABLED; 839 /* 840 * If a cancellation was requested while cancellation 841 * was disabled, note that fact for future 842 * cancellation tests. 843 */ 844 if (self->pt_flags & PT_FLAG_CS_PENDING) { 845 self->pt_cancel = 1; 846 /* This is not a deferred cancellation point. */ 847 if (self->pt_flags & PT_FLAG_CS_ASYNC) { 848 pthread_mutex_unlock(&self->pt_lock); 849 pthread__cancelled(); 850 } 851 } 852 } else 853 retval = EINVAL; 854 855 pthread_mutex_unlock(&self->pt_lock); 856 857 return retval; 858 } 859 860 861 int 862 pthread_setcanceltype(int type, int *oldtype) 863 { 864 pthread_t self; 865 int retval; 866 867 self = pthread__self(); 868 retval = 0; 869 870 pthread_mutex_lock(&self->pt_lock); 871 872 if (oldtype != NULL) { 873 if (self->pt_flags & PT_FLAG_CS_ASYNC) 874 *oldtype = PTHREAD_CANCEL_ASYNCHRONOUS; 875 else 876 *oldtype = PTHREAD_CANCEL_DEFERRED; 877 } 878 879 if (type == PTHREAD_CANCEL_ASYNCHRONOUS) { 880 self->pt_flags |= PT_FLAG_CS_ASYNC; 881 if (self->pt_cancel) { 882 pthread_mutex_unlock(&self->pt_lock); 883 pthread__cancelled(); 884 } 885 } else if (type == PTHREAD_CANCEL_DEFERRED) 886 self->pt_flags &= ~PT_FLAG_CS_ASYNC; 887 else 888 retval = EINVAL; 889 890 pthread_mutex_unlock(&self->pt_lock); 891 892 return retval; 893 } 894 895 896 void 897 pthread_testcancel(void) 898 { 899 pthread_t self; 900 901 self = pthread__self(); 902 if (self->pt_cancel) 903 pthread__cancelled(); 904 } 905 906 907 /* 908 * POSIX requires that certain functions return an error rather than 909 * invoking undefined behavior even when handed completely bogus 910 * pthread_t values, e.g. stack garbage or (pthread_t)666. This 911 * utility routine searches the list of threads for the pthread_t 912 * value without dereferencing it. 913 */ 914 int 915 pthread__find(pthread_t id) 916 { 917 pthread_t target; 918 919 pthread_rwlock_rdlock(&pthread__alltree_lock); 920 /* LINTED */ 921 target = RB_FIND(__pthread__alltree, &pthread__alltree, id); 922 pthread_rwlock_unlock(&pthread__alltree_lock); 923 924 if (target == NULL || target->pt_state == PT_STATE_DEAD) 925 return ESRCH; 926 927 return 0; 928 } 929 930 931 void 932 pthread__testcancel(pthread_t self) 933 { 934 935 if (self->pt_cancel) 936 pthread__cancelled(); 937 } 938 939 940 void 941 pthread__cancelled(void) 942 { 943 pthread_mutex_t *droplock; 944 pthread_t self; 945 946 self = pthread__self(); 947 droplock = self->pt_droplock; 948 self->pt_droplock = NULL; 949 950 if (droplock != NULL && pthread_mutex_held_np(droplock)) 951 pthread_mutex_unlock(droplock); 952 953 pthread_exit(PTHREAD_CANCELED); 954 } 955 956 957 void 958 pthread__cleanup_push(void (*cleanup)(void *), void *arg, void *store) 959 { 960 pthread_t self; 961 struct pt_clean_t *entry; 962 963 self = pthread__self(); 964 entry = store; 965 entry->ptc_cleanup = cleanup; 966 entry->ptc_arg = arg; 967 PTQ_INSERT_HEAD(&self->pt_cleanup_stack, entry, ptc_next); 968 } 969 970 971 void 972 pthread__cleanup_pop(int ex, void *store) 973 { 974 pthread_t self; 975 struct pt_clean_t *entry; 976 977 self = pthread__self(); 978 entry = store; 979 980 PTQ_REMOVE(&self->pt_cleanup_stack, entry, ptc_next); 981 if (ex) 982 (*entry->ptc_cleanup)(entry->ptc_arg); 983 } 984 985 986 int * 987 pthread__errno(void) 988 { 989 pthread_t self; 990 991 self = pthread__self(); 992 993 return &(self->pt_errno); 994 } 995 996 ssize_t _sys_write(int, const void *, size_t); 997 998 void 999 pthread__assertfunc(const char *file, int line, const char *function, 1000 const char *expr) 1001 { 1002 char buf[1024]; 1003 int len; 1004 1005 /* 1006 * snprintf should not acquire any locks, or we could 1007 * end up deadlocked if the assert caller held locks. 1008 */ 1009 len = snprintf(buf, 1024, 1010 "assertion \"%s\" failed: file \"%s\", line %d%s%s%s\n", 1011 expr, file, line, 1012 function ? ", function \"" : "", 1013 function ? function : "", 1014 function ? "\"" : ""); 1015 1016 _sys_write(STDERR_FILENO, buf, (size_t)len); 1017 (void)kill(getpid(), SIGABRT); 1018 1019 _exit(1); 1020 } 1021 1022 1023 void 1024 pthread__errorfunc(const char *file, int line, const char *function, 1025 const char *msg) 1026 { 1027 char buf[1024]; 1028 size_t len; 1029 1030 if (pthread__diagassert == 0) 1031 return; 1032 1033 /* 1034 * snprintf should not acquire any locks, or we could 1035 * end up deadlocked if the assert caller held locks. 1036 */ 1037 len = snprintf(buf, 1024, 1038 "%s: Error detected by libpthread: %s.\n" 1039 "Detected by file \"%s\", line %d%s%s%s.\n" 1040 "See pthread(3) for information.\n", 1041 getprogname(), msg, file, line, 1042 function ? ", function \"" : "", 1043 function ? function : "", 1044 function ? "\"" : ""); 1045 1046 if (pthread__diagassert & DIAGASSERT_STDERR) 1047 _sys_write(STDERR_FILENO, buf, len); 1048 1049 if (pthread__diagassert & DIAGASSERT_SYSLOG) 1050 syslog(LOG_DEBUG | LOG_USER, "%s", buf); 1051 1052 if (pthread__diagassert & DIAGASSERT_ABORT) { 1053 (void)kill(getpid(), SIGABRT); 1054 _exit(1); 1055 } 1056 } 1057 1058 /* 1059 * Thread park/unpark operations. The kernel operations are 1060 * modelled after a brief description from "Multithreading in 1061 * the Solaris Operating Environment": 1062 * 1063 * http://www.sun.com/software/whitepapers/solaris9/multithread.pdf 1064 */ 1065 1066 #define OOPS(msg) \ 1067 pthread__errorfunc(__FILE__, __LINE__, __func__, msg) 1068 1069 int 1070 pthread__park(pthread_t self, pthread_mutex_t *lock, 1071 pthread_queue_t *queue, const struct timespec *abstime, 1072 int cancelpt, const void *hint) 1073 { 1074 int rv, error; 1075 void *obj; 1076 1077 /* 1078 * For non-interlocked release of mutexes we need a store 1079 * barrier before incrementing pt_blocking away from zero. 1080 * This is provided by pthread_mutex_unlock(). 1081 */ 1082 self->pt_willpark = 1; 1083 pthread_mutex_unlock(lock); 1084 self->pt_willpark = 0; 1085 self->pt_blocking++; 1086 1087 /* 1088 * Wait until we are awoken by a pending unpark operation, 1089 * a signal, an unpark posted after we have gone asleep, 1090 * or an expired timeout. 1091 * 1092 * It is fine to test the value of pt_sleepobj without 1093 * holding any locks, because: 1094 * 1095 * o Only the blocking thread (this thread) ever sets them 1096 * to a non-NULL value. 1097 * 1098 * o Other threads may set them NULL, but if they do so they 1099 * must also make this thread return from _lwp_park. 1100 * 1101 * o _lwp_park, _lwp_unpark and _lwp_unpark_all are system 1102 * calls and all make use of spinlocks in the kernel. So 1103 * these system calls act as full memory barriers, and will 1104 * ensure that the calling CPU's store buffers are drained. 1105 * In combination with the spinlock release before unpark, 1106 * this means that modification of pt_sleepobj/onq by another 1107 * thread will become globally visible before that thread 1108 * schedules an unpark operation on this thread. 1109 * 1110 * Note: the test in the while() statement dodges the park op if 1111 * we have already been awoken, unless there is another thread to 1112 * awaken. This saves a syscall - if we were already awakened, 1113 * the next call to _lwp_park() would need to return early in order 1114 * to eat the previous wakeup. 1115 */ 1116 rv = 0; 1117 do { 1118 /* 1119 * If we deferred unparking a thread, arrange to 1120 * have _lwp_park() restart it before blocking. 1121 */ 1122 error = _lwp_park(abstime, self->pt_unpark, hint, hint); 1123 self->pt_unpark = 0; 1124 if (error != 0) { 1125 switch (rv = errno) { 1126 case EINTR: 1127 case EALREADY: 1128 rv = 0; 1129 break; 1130 case ETIMEDOUT: 1131 break; 1132 default: 1133 OOPS("_lwp_park failed"); 1134 break; 1135 } 1136 } 1137 /* Check for cancellation. */ 1138 if (cancelpt && self->pt_cancel) 1139 rv = EINTR; 1140 } while (self->pt_sleepobj != NULL && rv == 0); 1141 1142 /* 1143 * If we have been awoken early but are still on the queue, 1144 * then remove ourself. Again, it's safe to do the test 1145 * without holding any locks. 1146 */ 1147 if (__predict_false(self->pt_sleepobj != NULL)) { 1148 pthread_mutex_lock(lock); 1149 if ((obj = self->pt_sleepobj) != NULL) { 1150 PTQ_REMOVE(queue, self, pt_sleep); 1151 self->pt_sleepobj = NULL; 1152 if (obj != NULL && self->pt_early != NULL) 1153 (*self->pt_early)(obj); 1154 } 1155 pthread_mutex_unlock(lock); 1156 } 1157 self->pt_early = NULL; 1158 self->pt_blocking--; 1159 membar_sync(); 1160 1161 return rv; 1162 } 1163 1164 void 1165 pthread__unpark(pthread_queue_t *queue, pthread_t self, 1166 pthread_mutex_t *interlock) 1167 { 1168 pthread_t target; 1169 u_int max; 1170 size_t nwaiters; 1171 1172 max = pthread__unpark_max; 1173 nwaiters = self->pt_nwaiters; 1174 target = PTQ_FIRST(queue); 1175 if (nwaiters == max) { 1176 /* Overflow. */ 1177 (void)_lwp_unpark_all(self->pt_waiters, nwaiters, 1178 __UNVOLATILE(&interlock->ptm_waiters)); 1179 nwaiters = 0; 1180 } 1181 target->pt_sleepobj = NULL; 1182 self->pt_waiters[nwaiters++] = target->pt_lid; 1183 PTQ_REMOVE(queue, target, pt_sleep); 1184 self->pt_nwaiters = nwaiters; 1185 pthread__mutex_deferwake(self, interlock); 1186 } 1187 1188 void 1189 pthread__unpark_all(pthread_queue_t *queue, pthread_t self, 1190 pthread_mutex_t *interlock) 1191 { 1192 pthread_t target; 1193 u_int max; 1194 size_t nwaiters; 1195 1196 max = pthread__unpark_max; 1197 nwaiters = self->pt_nwaiters; 1198 PTQ_FOREACH(target, queue, pt_sleep) { 1199 if (nwaiters == max) { 1200 /* Overflow. */ 1201 (void)_lwp_unpark_all(self->pt_waiters, nwaiters, 1202 __UNVOLATILE(&interlock->ptm_waiters)); 1203 nwaiters = 0; 1204 } 1205 target->pt_sleepobj = NULL; 1206 self->pt_waiters[nwaiters++] = target->pt_lid; 1207 } 1208 self->pt_nwaiters = nwaiters; 1209 PTQ_INIT(queue); 1210 pthread__mutex_deferwake(self, interlock); 1211 } 1212 1213 #undef OOPS 1214 1215 static void 1216 pthread__initmainstack(void) 1217 { 1218 struct rlimit slimit; 1219 const AuxInfo *aux; 1220 size_t size; 1221 1222 _DIAGASSERT(_dlauxinfo() != NULL); 1223 1224 if (getrlimit(RLIMIT_STACK, &slimit) == -1) 1225 err(1, "Couldn't get stack resource consumption limits"); 1226 size = slimit.rlim_cur; 1227 pthread__main.pt_stack.ss_size = size; 1228 1229 for (aux = _dlauxinfo(); aux->a_type != AT_NULL; ++aux) { 1230 if (aux->a_type == AT_STACKBASE) { 1231 pthread__main.pt_stack.ss_sp = (void *)aux->a_v; 1232 #ifdef __MACHINE_STACK_GROWS_UP 1233 pthread__main.pt_stack.ss_sp = (void *)aux->a_v; 1234 #else 1235 pthread__main.pt_stack.ss_sp = (char *)aux->a_v - size; 1236 #endif 1237 break; 1238 } 1239 } 1240 } 1241 1242 /* 1243 * Set up the slightly special stack for the "initial" thread, which 1244 * runs on the normal system stack, and thus gets slightly different 1245 * treatment. 1246 */ 1247 static void 1248 pthread__initmain(pthread_t *newt) 1249 { 1250 char *value; 1251 1252 pthread__initmainstack(); 1253 1254 value = pthread__getenv("PTHREAD_STACKSIZE"); 1255 if (value != NULL) { 1256 pthread__stacksize = atoi(value) * 1024; 1257 if (pthread__stacksize > pthread__main.pt_stack.ss_size) 1258 pthread__stacksize = pthread__main.pt_stack.ss_size; 1259 } 1260 if (pthread__stacksize == 0) 1261 pthread__stacksize = pthread__main.pt_stack.ss_size; 1262 pthread__stacksize += pthread__pagesize - 1; 1263 pthread__stacksize &= ~pthread__pagesize; 1264 if (pthread__stacksize < 4 * pthread__pagesize) 1265 errx(1, "Stacksize limit is too low, minimum %zd kbyte.", 1266 4 * pthread__pagesize / 1024); 1267 1268 *newt = &pthread__main; 1269 #if defined(__HAVE_TLS_VARIANT_I) || defined(__HAVE_TLS_VARIANT_II) 1270 # ifdef __HAVE___LWP_GETTCB_FAST 1271 pthread__main.pt_tls = __lwp_gettcb_fast(); 1272 # else 1273 pthread__main.pt_tls = _lwp_getprivate(); 1274 # endif 1275 pthread__main.pt_tls->tcb_pthread = &pthread__main; 1276 #endif 1277 } 1278 1279 #ifndef lint 1280 static int 1281 pthread__cmp(struct __pthread_st *a, struct __pthread_st *b) 1282 { 1283 1284 if ((uintptr_t)a < (uintptr_t)b) 1285 return (-1); 1286 else if (a == b) 1287 return 0; 1288 else 1289 return 1; 1290 } 1291 RB_GENERATE_STATIC(__pthread__alltree, __pthread_st, pt_alltree, pthread__cmp) 1292 #endif 1293 1294 /* Because getenv() wants to use locks. */ 1295 char * 1296 pthread__getenv(const char *name) 1297 { 1298 extern char **environ; 1299 size_t l_name, offset; 1300 1301 l_name = strlen(name); 1302 for (offset = 0; environ[offset] != NULL; offset++) { 1303 if (strncmp(name, environ[offset], l_name) == 0 && 1304 environ[offset][l_name] == '=') { 1305 return environ[offset] + l_name + 1; 1306 } 1307 } 1308 1309 return NULL; 1310 } 1311 1312 pthread_mutex_t * 1313 pthread__hashlock(volatile const void *p) 1314 { 1315 uintptr_t v; 1316 1317 v = (uintptr_t)p; 1318 return &hashlocks[((v >> 9) ^ (v >> 3)) & (NHASHLOCK - 1)].mutex; 1319 } 1320 1321 int 1322 pthread__checkpri(int pri) 1323 { 1324 static int havepri; 1325 static long min, max; 1326 1327 if (!havepri) { 1328 min = sysconf(_SC_SCHED_PRI_MIN); 1329 max = sysconf(_SC_SCHED_PRI_MAX); 1330 havepri = 1; 1331 } 1332 return (pri < min || pri > max) ? EINVAL : 0; 1333 } 1334