thr_sig.c revision 212841
1/* 2 * Copyright (c) 2005, David Xu <davidxu@freebsd.org> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice unmodified, this list of conditions, and the following 10 * disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 * 26 * $FreeBSD: head/lib/libthr/thread/thr_sig.c 212841 2010-09-19 09:03:11Z davidxu $ 27 */ 28 29#include "namespace.h" 30#include <sys/param.h> 31#include <sys/types.h> 32#include <sys/signalvar.h> 33#include <signal.h> 34#include <errno.h> 35#include <string.h> 36#include <pthread.h> 37#include "un-namespace.h" 38#include "libc_private.h" 39 40#include "thr_private.h" 41 42/* #define DEBUG_SIGNAL */ 43#ifdef DEBUG_SIGNAL 44#define DBG_MSG stdout_debug 45#else 46#define DBG_MSG(x...) 47#endif 48 49struct usigaction { 50 struct sigaction sigact; 51 struct urwlock lock; 52}; 53 54static struct usigaction _thr_sigact[_SIG_MAXSIG]; 55 56static void thr_sighandler(int, siginfo_t *, void *); 57static void handle_signal(struct sigaction *, int, siginfo_t *, ucontext_t *); 58static void check_deferred_signal(struct pthread *); 59static void check_suspend(struct pthread *); 60static void check_cancel(struct pthread *curthread, ucontext_t *ucp); 61 62int ___pause(void); 63int _raise(int); 64int __sigtimedwait(const sigset_t *set, siginfo_t *info, 65 const struct timespec * timeout); 66int _sigtimedwait(const sigset_t *set, siginfo_t *info, 67 const struct timespec * timeout); 68int __sigwaitinfo(const sigset_t *set, siginfo_t *info); 69int _sigwaitinfo(const sigset_t *set, siginfo_t *info); 70int ___sigwait(const sigset_t *set, int *sig); 71int _sigwait(const sigset_t *set, int *sig); 72int __sigsuspend(const sigset_t *sigmask); 73int _sigaction(int, const struct sigaction *, struct sigaction *); 74int _setcontext(const ucontext_t *); 75int _swapcontext(ucontext_t *, const ucontext_t *); 76 77static const sigset_t _thr_deferset={{ 78 0xffffffff & ~(_SIG_BIT(SIGBUS)|_SIG_BIT(SIGILL)|_SIG_BIT(SIGFPE)| 79 _SIG_BIT(SIGSEGV)|_SIG_BIT(SIGTRAP)|_SIG_BIT(SIGSYS)), 80 0xffffffff, 81 0xffffffff, 82 0xffffffff}}; 83 84static const sigset_t _thr_maskset={{ 85 0xffffffff, 86 0xffffffff, 87 0xffffffff, 88 0xffffffff}}; 89 90void 91_thr_signal_block(struct pthread *curthread) 92{ 93 94 if (curthread->sigblock > 0) { 95 curthread->sigblock++; 96 return; 97 } 98 __sys_sigprocmask(SIG_BLOCK, &_thr_maskset, &curthread->sigmask); 99 curthread->sigblock++; 100} 101 102void 103_thr_signal_unblock(struct pthread *curthread) 104{ 105 if (--curthread->sigblock == 0) 106 __sys_sigprocmask(SIG_SETMASK, &curthread->sigmask, NULL); 107} 108 109int 110_thr_send_sig(struct pthread *thread, int sig) 111{ 112 return thr_kill(thread->tid, sig); 113} 114 115static inline void 116remove_thr_signals(sigset_t *set) 117{ 118 if (SIGISMEMBER(*set, SIGCANCEL)) 119 SIGDELSET(*set, SIGCANCEL); 120} 121 122static const sigset_t * 123thr_remove_thr_signals(const sigset_t *set, sigset_t *newset) 124{ 125 *newset = *set; 126 remove_thr_signals(newset); 127 return (newset); 128} 129 130static void 131sigcancel_handler(int sig __unused, 132 siginfo_t *info __unused, ucontext_t *ucp) 133{ 134 struct pthread *curthread = _get_curthread(); 135 int err; 136 137 if (THR_IN_CRITICAL(curthread)) 138 return; 139 err = errno; 140 check_suspend(curthread); 141 check_cancel(curthread, ucp); 142 errno = err; 143} 144 145typedef void (*ohandler)(int sig, int code, 146 struct sigcontext *scp, char *addr, __sighandler_t *catcher); 147 148/* 149 * The signal handler wrapper is entered with all signal masked. 150 */ 151static void 152thr_sighandler(int sig, siginfo_t *info, void *_ucp) 153{ 154 struct pthread *curthread = _get_curthread(); 155 ucontext_t *ucp = _ucp; 156 struct sigaction act; 157 int err; 158 159 err = errno; 160 _thr_rwl_rdlock(&_thr_sigact[sig-1].lock); 161 act = _thr_sigact[sig-1].sigact; 162 _thr_rwl_unlock(&_thr_sigact[sig-1].lock); 163 errno = err; 164 165 /* 166 * if a thread is in critical region, for example it holds low level locks, 167 * try to defer the signal processing, however if the signal is synchronous 168 * signal, it means a bad thing has happened, this is a programming error, 169 * resuming fault point can not help anything (normally causes deadloop), 170 * so here we let user code handle it immediately. 171 */ 172 if (THR_IN_CRITICAL(curthread) && SIGISMEMBER(_thr_deferset, sig)) { 173 memcpy(&curthread->deferred_sigact, &act, sizeof(struct sigaction)); 174 memcpy(&curthread->deferred_siginfo, info, sizeof(siginfo_t)); 175 curthread->deferred_sigmask = ucp->uc_sigmask; 176 /* mask all signals, we will restore it later. */ 177 ucp->uc_sigmask = _thr_deferset; 178 return; 179 } 180 181 handle_signal(&act, sig, info, ucp); 182} 183 184static void 185handle_signal(struct sigaction *actp, int sig, siginfo_t *info, ucontext_t *ucp) 186{ 187 struct pthread *curthread = _get_curthread(); 188 ucontext_t uc2; 189 __siginfohandler_t *sigfunc; 190 int cancel_point; 191 int cancel_async; 192 int cancel_enable; 193 int in_sigsuspend; 194 int err; 195 196 /* add previous level mask */ 197 SIGSETOR(actp->sa_mask, ucp->uc_sigmask); 198 199 /* add this signal's mask */ 200 if (!(actp->sa_flags & SA_NODEFER)) 201 SIGADDSET(actp->sa_mask, sig); 202 203 in_sigsuspend = curthread->in_sigsuspend; 204 curthread->in_sigsuspend = 0; 205 206 /* 207 * if thread is in deferred cancellation mode, disable cancellation 208 * in signal handler. 209 * if user signal handler calls a cancellation point function, e.g, 210 * it calls write() to write data to file, because write() is a 211 * cancellation point, the thread is immediately cancelled if 212 * cancellation is pending, to avoid this problem while thread is in 213 * deferring mode, cancellation is temporarily disabled. 214 */ 215 cancel_point = curthread->cancel_point; 216 cancel_async = curthread->cancel_async; 217 cancel_enable = curthread->cancel_enable; 218 curthread->cancel_point = 0; 219 if (!cancel_async) 220 curthread->cancel_enable = 0; 221 222 /* restore correct mask before calling user handler */ 223 __sys_sigprocmask(SIG_SETMASK, &actp->sa_mask, NULL); 224 225 sigfunc = actp->sa_sigaction; 226 227 /* 228 * We have already reset cancellation point flags, so if user's code 229 * longjmp()s out of its signal handler, wish its jmpbuf was set 230 * outside of a cancellation point, in most cases, this would be 231 * true. however, ther is no way to save cancel_enable in jmpbuf, 232 * so after setjmps() returns once more, the user code may need to 233 * re-set cancel_enable flag by calling pthread_setcancelstate(). 234 */ 235 if ((actp->sa_flags & SA_SIGINFO) != 0) 236 (*(sigfunc))(sig, info, ucp); 237 else { 238 ((ohandler)(*sigfunc))( 239 sig, info->si_code, (struct sigcontext *)ucp, 240 info->si_addr, (__sighandler_t *)sigfunc); 241 } 242 err = errno; 243 244 curthread->in_sigsuspend = in_sigsuspend; 245 curthread->cancel_point = cancel_point; 246 curthread->cancel_enable = cancel_enable; 247 248 memcpy(&uc2, ucp, sizeof(uc2)); 249 SIGDELSET(uc2.uc_sigmask, SIGCANCEL); 250 251 /* reschedule cancellation */ 252 check_cancel(curthread, &uc2); 253 errno = err; 254 __sys_sigreturn(&uc2); 255} 256 257void 258_thr_ast(struct pthread *curthread) 259{ 260 261 if (!THR_IN_CRITICAL(curthread)) { 262 check_deferred_signal(curthread); 263 check_suspend(curthread); 264 check_cancel(curthread, NULL); 265 } 266} 267 268/* reschedule cancellation */ 269static void 270check_cancel(struct pthread *curthread, ucontext_t *ucp) 271{ 272 273 if (__predict_true(!curthread->cancel_pending || !curthread->cancel_enable || 274 curthread->no_cancel)) 275 return; 276 277 if (curthread->cancel_async) { 278 /* 279 * asynchronous cancellation mode, act upon 280 * immediately. 281 */ 282 _pthread_exit_mask(PTHREAD_CANCELED, 283 ucp? &ucp->uc_sigmask : NULL); 284 } else { 285 /* 286 * Otherwise, we are in defer mode, and we are at 287 * cancel point, tell kernel to not block the current 288 * thread on next cancelable system call. 289 * 290 * There are three cases we should call thr_wake() to 291 * turn on TDP_WAKEUP or send SIGCANCEL in kernel: 292 * 1) we are going to call a cancelable system call, 293 * non-zero cancel_point means we are already in 294 * cancelable state, next system call is cancelable. 295 * 2) because _thr_ast() may be called by 296 * THR_CRITICAL_LEAVE() which is used by rtld rwlock 297 * and any libthr internal locks, when rtld rwlock 298 * is used, it is mostly caused my an unresolved PLT. 299 * those routines may clear the TDP_WAKEUP flag by 300 * invoking some system calls, in those cases, we 301 * also should reenable the flag. 302 * 3) thread is in sigsuspend(), and the syscall insists 303 * on getting a signal before it agrees to return. 304 */ 305 if (curthread->cancel_point) { 306 if (curthread->in_sigsuspend && ucp) { 307 SIGADDSET(ucp->uc_sigmask, SIGCANCEL); 308 curthread->unblock_sigcancel = 1; 309 _thr_send_sig(curthread, SIGCANCEL); 310 } else 311 thr_wake(curthread->tid); 312 } 313 } 314} 315 316static void 317check_deferred_signal(struct pthread *curthread) 318{ 319 ucontext_t uc; 320 struct sigaction act; 321 siginfo_t info; 322 volatile int first; 323 324 if (__predict_true(curthread->deferred_siginfo.si_signo == 0)) 325 return; 326 first = 1; 327 getcontext(&uc); 328 if (first) { 329 first = 0; 330 act = curthread->deferred_sigact; 331 uc.uc_sigmask = curthread->deferred_sigmask; 332 memcpy(&info, &curthread->deferred_siginfo, sizeof(siginfo_t)); 333 /* remove signal */ 334 curthread->deferred_siginfo.si_signo = 0; 335 if (act.sa_flags & SA_RESETHAND) { 336 struct sigaction tact; 337 338 tact = act; 339 tact.sa_handler = SIG_DFL; 340 _sigaction(info.si_signo, &tact, NULL); 341 } 342 handle_signal(&act, info.si_signo, &info, &uc); 343 } 344} 345 346static void 347check_suspend(struct pthread *curthread) 348{ 349 uint32_t cycle; 350 351 if (__predict_true((curthread->flags & 352 (THR_FLAGS_NEED_SUSPEND | THR_FLAGS_SUSPENDED)) 353 != THR_FLAGS_NEED_SUSPEND)) 354 return; 355 356 if (curthread->force_exit) 357 return; 358 359 /* 360 * Blocks SIGCANCEL which other threads must send. 361 */ 362 _thr_signal_block(curthread); 363 364 /* 365 * Increase critical_count, here we don't use THR_LOCK/UNLOCK 366 * because we are leaf code, we don't want to recursively call 367 * ourself. 368 */ 369 curthread->critical_count++; 370 THR_UMUTEX_LOCK(curthread, &(curthread)->lock); 371 while ((curthread->flags & (THR_FLAGS_NEED_SUSPEND | 372 THR_FLAGS_SUSPENDED)) == THR_FLAGS_NEED_SUSPEND) { 373 curthread->cycle++; 374 cycle = curthread->cycle; 375 376 /* Wake the thread suspending us. */ 377 _thr_umtx_wake(&curthread->cycle, INT_MAX, 0); 378 379 /* 380 * if we are from pthread_exit, we don't want to 381 * suspend, just go and die. 382 */ 383 if (curthread->state == PS_DEAD) 384 break; 385 curthread->flags |= THR_FLAGS_SUSPENDED; 386 THR_UMUTEX_UNLOCK(curthread, &(curthread)->lock); 387 _thr_umtx_wait_uint(&curthread->cycle, cycle, NULL, 0); 388 THR_UMUTEX_LOCK(curthread, &(curthread)->lock); 389 curthread->flags &= ~THR_FLAGS_SUSPENDED; 390 } 391 THR_UMUTEX_UNLOCK(curthread, &(curthread)->lock); 392 curthread->critical_count--; 393 394 _thr_signal_unblock(curthread); 395} 396 397void 398_thr_signal_init(void) 399{ 400 struct sigaction act; 401 402 /* Install SIGCANCEL handler. */ 403 SIGFILLSET(act.sa_mask); 404 act.sa_flags = SA_SIGINFO; 405 act.sa_sigaction = (__siginfohandler_t *)&sigcancel_handler; 406 __sys_sigaction(SIGCANCEL, &act, NULL); 407 408 /* Unblock SIGCANCEL */ 409 SIGEMPTYSET(act.sa_mask); 410 SIGADDSET(act.sa_mask, SIGCANCEL); 411 __sys_sigprocmask(SIG_UNBLOCK, &act.sa_mask, NULL); 412} 413 414void 415_thr_sigact_unload(struct dl_phdr_info *phdr_info) 416{ 417#if 0 418 struct pthread *curthread = _get_curthread(); 419 struct urwlock *rwlp; 420 struct sigaction *actp; 421 struct sigaction kact; 422 void (*handler)(int); 423 int sig; 424 425 _thr_signal_block(curthread); 426 for (sig = 1; sig <= _SIG_MAXSIG; sig++) { 427 actp = &_thr_sigact[sig-1].sigact; 428retry: 429 handler = actp->sa_handler; 430 if (handler != SIG_DFL && handler != SIG_IGN && 431 __elf_phdr_match_addr(phdr_info, handler)) { 432 rwlp = &_thr_sigact[sig-1].lock; 433 _thr_rwl_wrlock(rwlp); 434 if (handler != actp->sa_handler) { 435 _thr_rwl_unlock(rwlp); 436 goto retry; 437 } 438 actp->sa_handler = SIG_DFL; 439 actp->sa_flags = SA_SIGINFO; 440 SIGEMPTYSET(actp->sa_mask); 441 if (__sys_sigaction(sig, NULL, &kact) == 0 && 442 kact.sa_handler != SIG_DFL && 443 kact.sa_handler != SIG_IGN) 444 __sys_sigaction(sig, actp, NULL); 445 _thr_rwl_unlock(rwlp); 446 } 447 } 448 _thr_signal_unblock(curthread); 449#endif 450} 451 452void 453_thr_signal_prefork(void) 454{ 455 int i; 456 457 for (i = 1; i < _SIG_MAXSIG; ++i) 458 _thr_rwl_rdlock(&_thr_sigact[i-1].lock); 459} 460 461void 462_thr_signal_postfork(void) 463{ 464 int i; 465 466 for (i = 1; i < _SIG_MAXSIG; ++i) 467 _thr_rwl_unlock(&_thr_sigact[i-1].lock); 468} 469 470void 471_thr_signal_postfork_child(void) 472{ 473 int i; 474 475 for (i = 1; i < _SIG_MAXSIG; ++i) 476 bzero(&_thr_sigact[i-1].lock, sizeof(struct urwlock)); 477} 478 479void 480_thr_signal_deinit(void) 481{ 482} 483 484__weak_reference(___pause, pause); 485 486int 487___pause(void) 488{ 489 sigset_t oset; 490 491 if (_sigprocmask(SIG_BLOCK, NULL, &oset) == -1) 492 return (-1); 493 return (__sigsuspend(&oset)); 494} 495 496__weak_reference(_raise, raise); 497 498int 499_raise(int sig) 500{ 501 return _thr_send_sig(_get_curthread(), sig); 502} 503 504__weak_reference(_sigaction, sigaction); 505 506int 507_sigaction(int sig, const struct sigaction * act, struct sigaction * oact) 508{ 509 struct sigaction newact, oldact, oldact2; 510 sigset_t oldset; 511 int ret = 0, err = 0; 512 513 if (!_SIG_VALID(sig) || sig == SIGCANCEL) { 514 errno = EINVAL; 515 return (-1); 516 } 517 518 if (act) 519 newact = *act; 520 521 __sys_sigprocmask(SIG_SETMASK, &_thr_maskset, &oldset); 522 _thr_rwl_wrlock(&_thr_sigact[sig-1].lock); 523 524 if (act != NULL) { 525 oldact2 = _thr_sigact[sig-1].sigact; 526 527 /* 528 * if a new sig handler is SIG_DFL or SIG_IGN, 529 * don't remove old handler from _thr_sigact[], 530 * so deferred signals still can use the handlers, 531 * multiple threads invoking sigaction itself is 532 * a race condition, so it is not a problem. 533 */ 534 if (newact.sa_handler != SIG_DFL && 535 newact.sa_handler != SIG_IGN) { 536 _thr_sigact[sig-1].sigact = newact; 537 remove_thr_signals( 538 &_thr_sigact[sig-1].sigact.sa_mask); 539 newact.sa_flags &= ~SA_NODEFER; 540 newact.sa_flags |= SA_SIGINFO; 541 newact.sa_sigaction = thr_sighandler; 542 newact.sa_mask = _thr_maskset; /* mask all signals */ 543 } 544 if ((ret = __sys_sigaction(sig, &newact, &oldact))) { 545 err = errno; 546 _thr_sigact[sig-1].sigact = oldact2; 547 } 548 } else if (oact != NULL) { 549 ret = __sys_sigaction(sig, NULL, &oldact); 550 err = errno; 551 } 552 553 if (oldact.sa_handler != SIG_DFL && 554 oldact.sa_handler != SIG_IGN) { 555 oldact = _thr_sigact[sig-1].sigact; 556 } 557 558 _thr_rwl_unlock(&_thr_sigact[sig-1].lock); 559 __sys_sigprocmask(SIG_SETMASK, &oldset, NULL); 560 561 if (ret == 0) { 562 if (oact != NULL) 563 *oact = oldact; 564 } else { 565 errno = err; 566 } 567 return (ret); 568} 569 570__weak_reference(_sigprocmask, sigprocmask); 571 572int 573_sigprocmask(int how, const sigset_t *set, sigset_t *oset) 574{ 575 const sigset_t *p = set; 576 sigset_t newset; 577 578 if (how != SIG_UNBLOCK) { 579 if (set != NULL) { 580 newset = *set; 581 SIGDELSET(newset, SIGCANCEL); 582 p = &newset; 583 } 584 } 585 return (__sys_sigprocmask(how, p, oset)); 586} 587 588__weak_reference(_pthread_sigmask, pthread_sigmask); 589 590int 591_pthread_sigmask(int how, const sigset_t *set, sigset_t *oset) 592{ 593 if (_sigprocmask(how, set, oset)) 594 return (errno); 595 return (0); 596} 597 598__weak_reference(__sigsuspend, sigsuspend); 599 600int 601_sigsuspend(const sigset_t * set) 602{ 603 sigset_t newset; 604 605 return (__sys_sigsuspend(thr_remove_thr_signals(set, &newset))); 606} 607 608int 609__sigsuspend(const sigset_t * set) 610{ 611 struct pthread *curthread; 612 sigset_t newset; 613 int ret, old; 614 615 curthread = _get_curthread(); 616 617 old = curthread->in_sigsuspend; 618 curthread->in_sigsuspend = 1; 619 _thr_cancel_enter(curthread); 620 ret = __sys_sigsuspend(thr_remove_thr_signals(set, &newset)); 621 _thr_cancel_leave(curthread, 1); 622 curthread->in_sigsuspend = old; 623 if (curthread->unblock_sigcancel) { 624 curthread->unblock_sigcancel = 0; 625 SIGEMPTYSET(newset); 626 SIGADDSET(newset, SIGCANCEL); 627 __sys_sigprocmask(SIG_UNBLOCK, &newset, NULL); 628 } 629 630 return (ret); 631} 632 633__weak_reference(___sigwait, sigwait); 634__weak_reference(__sigtimedwait, sigtimedwait); 635__weak_reference(__sigwaitinfo, sigwaitinfo); 636 637int 638_sigtimedwait(const sigset_t *set, siginfo_t *info, 639 const struct timespec * timeout) 640{ 641 sigset_t newset; 642 643 return (__sys_sigtimedwait(thr_remove_thr_signals(set, &newset), info, 644 timeout)); 645} 646 647/* 648 * Cancellation behavior: 649 * Thread may be canceled at start, if thread got signal, 650 * it is not canceled. 651 */ 652int 653__sigtimedwait(const sigset_t *set, siginfo_t *info, 654 const struct timespec * timeout) 655{ 656 struct pthread *curthread = _get_curthread(); 657 sigset_t newset; 658 int ret; 659 660 _thr_cancel_enter(curthread); 661 ret = __sys_sigtimedwait(thr_remove_thr_signals(set, &newset), info, 662 timeout); 663 _thr_cancel_leave(curthread, (ret == -1)); 664 return (ret); 665} 666 667int 668_sigwaitinfo(const sigset_t *set, siginfo_t *info) 669{ 670 sigset_t newset; 671 672 return (__sys_sigwaitinfo(thr_remove_thr_signals(set, &newset), info)); 673} 674 675/* 676 * Cancellation behavior: 677 * Thread may be canceled at start, if thread got signal, 678 * it is not canceled. 679 */ 680int 681__sigwaitinfo(const sigset_t *set, siginfo_t *info) 682{ 683 struct pthread *curthread = _get_curthread(); 684 sigset_t newset; 685 int ret; 686 687 _thr_cancel_enter(curthread); 688 ret = __sys_sigwaitinfo(thr_remove_thr_signals(set, &newset), info); 689 _thr_cancel_leave(curthread, ret == -1); 690 return (ret); 691} 692 693int 694_sigwait(const sigset_t *set, int *sig) 695{ 696 sigset_t newset; 697 698 return (__sys_sigwait(thr_remove_thr_signals(set, &newset), sig)); 699} 700 701/* 702 * Cancellation behavior: 703 * Thread may be canceled at start, if thread got signal, 704 * it is not canceled. 705 */ 706int 707___sigwait(const sigset_t *set, int *sig) 708{ 709 struct pthread *curthread = _get_curthread(); 710 sigset_t newset; 711 int ret; 712 713 do { 714 _thr_cancel_enter(curthread); 715 ret = __sys_sigwait(thr_remove_thr_signals(set, &newset), sig); 716 _thr_cancel_leave(curthread, (ret != 0)); 717 } while (ret == EINTR); 718 return (ret); 719} 720 721__weak_reference(_setcontext, setcontext); 722int 723_setcontext(const ucontext_t *ucp) 724{ 725 ucontext_t uc; 726 727 (void) memcpy(&uc, ucp, sizeof(uc)); 728 remove_thr_signals(&uc.uc_sigmask); 729 return __sys_setcontext(&uc); 730} 731 732__weak_reference(_swapcontext, swapcontext); 733int 734_swapcontext(ucontext_t *oucp, const ucontext_t *ucp) 735{ 736 ucontext_t uc; 737 738 (void) memcpy(&uc, ucp, sizeof(uc)); 739 remove_thr_signals(&uc.uc_sigmask); 740 return __sys_swapcontext(oucp, &uc); 741} 742