thr_sig.c revision 250013
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 250013 2013-04-28 03:13:45Z 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 <stdlib.h> 36#include <string.h> 37#include <pthread.h> 38#include "un-namespace.h" 39#include "libc_private.h" 40 41#include "thr_private.h" 42 43/* #define DEBUG_SIGNAL */ 44#ifdef DEBUG_SIGNAL 45#define DBG_MSG stdout_debug 46#else 47#define DBG_MSG(x...) 48#endif 49 50struct usigaction { 51 struct sigaction sigact; 52 struct urwlock lock; 53}; 54 55static struct usigaction _thr_sigact[_SIG_MAXSIG]; 56 57static void thr_sighandler(int, siginfo_t *, void *); 58static void handle_signal(struct sigaction *, int, siginfo_t *, ucontext_t *); 59static void check_deferred_signal(struct pthread *); 60static void check_suspend(struct pthread *); 61static void check_cancel(struct pthread *curthread, ucontext_t *ucp); 62 63int ___pause(void); 64int _raise(int); 65int __sigtimedwait(const sigset_t *set, siginfo_t *info, 66 const struct timespec * timeout); 67int _sigtimedwait(const sigset_t *set, siginfo_t *info, 68 const struct timespec * timeout); 69int __sigwaitinfo(const sigset_t *set, siginfo_t *info); 70int _sigwaitinfo(const sigset_t *set, siginfo_t *info); 71int ___sigwait(const sigset_t *set, int *sig); 72int _sigwait(const sigset_t *set, int *sig); 73int __sigsuspend(const sigset_t *sigmask); 74int _sigaction(int, const struct sigaction *, struct sigaction *); 75int _setcontext(const ucontext_t *); 76int _swapcontext(ucontext_t *, const ucontext_t *); 77 78static const sigset_t _thr_deferset={{ 79 0xffffffff & ~(_SIG_BIT(SIGBUS)|_SIG_BIT(SIGILL)|_SIG_BIT(SIGFPE)| 80 _SIG_BIT(SIGSEGV)|_SIG_BIT(SIGTRAP)|_SIG_BIT(SIGSYS)), 81 0xffffffff, 82 0xffffffff, 83 0xffffffff}}; 84 85static const sigset_t _thr_maskset={{ 86 0xffffffff, 87 0xffffffff, 88 0xffffffff, 89 0xffffffff}}; 90 91void 92_thr_signal_block(struct pthread *curthread) 93{ 94 95 if (curthread->sigblock > 0) { 96 curthread->sigblock++; 97 return; 98 } 99 __sys_sigprocmask(SIG_BLOCK, &_thr_maskset, &curthread->sigmask); 100 curthread->sigblock++; 101} 102 103void 104_thr_signal_unblock(struct pthread *curthread) 105{ 106 if (--curthread->sigblock == 0) 107 __sys_sigprocmask(SIG_SETMASK, &curthread->sigmask, NULL); 108} 109 110int 111_thr_send_sig(struct pthread *thread, int sig) 112{ 113 return thr_kill(thread->tid, sig); 114} 115 116static inline void 117remove_thr_signals(sigset_t *set) 118{ 119 if (SIGISMEMBER(*set, SIGCANCEL)) 120 SIGDELSET(*set, SIGCANCEL); 121} 122 123static const sigset_t * 124thr_remove_thr_signals(const sigset_t *set, sigset_t *newset) 125{ 126 *newset = *set; 127 remove_thr_signals(newset); 128 return (newset); 129} 130 131static void 132sigcancel_handler(int sig __unused, 133 siginfo_t *info __unused, ucontext_t *ucp) 134{ 135 struct pthread *curthread = _get_curthread(); 136 int err; 137 138 if (THR_IN_CRITICAL(curthread)) 139 return; 140 err = errno; 141 check_suspend(curthread); 142 check_cancel(curthread, ucp); 143 errno = err; 144} 145 146typedef void (*ohandler)(int sig, int code, 147 struct sigcontext *scp, char *addr, __sighandler_t *catcher); 148 149/* 150 * The signal handler wrapper is entered with all signal masked. 151 */ 152static void 153thr_sighandler(int sig, siginfo_t *info, void *_ucp) 154{ 155 struct pthread *curthread = _get_curthread(); 156 ucontext_t *ucp = _ucp; 157 struct sigaction act; 158 int err; 159 160 err = errno; 161 _thr_rwl_rdlock(&_thr_sigact[sig-1].lock); 162 act = _thr_sigact[sig-1].sigact; 163 _thr_rwl_unlock(&_thr_sigact[sig-1].lock); 164 errno = err; 165 166 /* 167 * if a thread is in critical region, for example it holds low level locks, 168 * try to defer the signal processing, however if the signal is synchronous 169 * signal, it means a bad thing has happened, this is a programming error, 170 * resuming fault point can not help anything (normally causes deadloop), 171 * so here we let user code handle it immediately. 172 */ 173 if (THR_IN_CRITICAL(curthread) && SIGISMEMBER(_thr_deferset, sig)) { 174 memcpy(&curthread->deferred_sigact, &act, sizeof(struct sigaction)); 175 memcpy(&curthread->deferred_siginfo, info, sizeof(siginfo_t)); 176 curthread->deferred_sigmask = ucp->uc_sigmask; 177 /* mask all signals, we will restore it later. */ 178 ucp->uc_sigmask = _thr_deferset; 179 return; 180 } 181 182 handle_signal(&act, sig, info, ucp); 183} 184 185static void 186handle_signal(struct sigaction *actp, int sig, siginfo_t *info, ucontext_t *ucp) 187{ 188 struct pthread *curthread = _get_curthread(); 189 ucontext_t uc2; 190 __siginfohandler_t *sigfunc; 191 int cancel_point; 192 int cancel_async; 193 int cancel_enable; 194 int in_sigsuspend; 195 int err; 196 197 /* add previous level mask */ 198 SIGSETOR(actp->sa_mask, ucp->uc_sigmask); 199 200 /* add this signal's mask */ 201 if (!(actp->sa_flags & SA_NODEFER)) 202 SIGADDSET(actp->sa_mask, sig); 203 204 in_sigsuspend = curthread->in_sigsuspend; 205 curthread->in_sigsuspend = 0; 206 207 /* 208 * if thread is in deferred cancellation mode, disable cancellation 209 * in signal handler. 210 * if user signal handler calls a cancellation point function, e.g, 211 * it calls write() to write data to file, because write() is a 212 * cancellation point, the thread is immediately cancelled if 213 * cancellation is pending, to avoid this problem while thread is in 214 * deferring mode, cancellation is temporarily disabled. 215 */ 216 cancel_point = curthread->cancel_point; 217 cancel_async = curthread->cancel_async; 218 cancel_enable = curthread->cancel_enable; 219 curthread->cancel_point = 0; 220 if (!cancel_async) 221 curthread->cancel_enable = 0; 222 223 /* restore correct mask before calling user handler */ 224 __sys_sigprocmask(SIG_SETMASK, &actp->sa_mask, NULL); 225 226 sigfunc = actp->sa_sigaction; 227 228 /* 229 * We have already reset cancellation point flags, so if user's code 230 * longjmp()s out of its signal handler, wish its jmpbuf was set 231 * outside of a cancellation point, in most cases, this would be 232 * true. however, ther is no way to save cancel_enable in jmpbuf, 233 * so after setjmps() returns once more, the user code may need to 234 * re-set cancel_enable flag by calling pthread_setcancelstate(). 235 */ 236 if ((actp->sa_flags & SA_SIGINFO) != 0) 237 (*(sigfunc))(sig, info, ucp); 238 else { 239 ((ohandler)(*sigfunc))( 240 sig, info->si_code, (struct sigcontext *)ucp, 241 info->si_addr, (__sighandler_t *)sigfunc); 242 } 243 err = errno; 244 245 curthread->in_sigsuspend = in_sigsuspend; 246 curthread->cancel_point = cancel_point; 247 curthread->cancel_enable = cancel_enable; 248 249 memcpy(&uc2, ucp, sizeof(uc2)); 250 SIGDELSET(uc2.uc_sigmask, SIGCANCEL); 251 252 /* reschedule cancellation */ 253 check_cancel(curthread, &uc2); 254 errno = err; 255 __sys_sigreturn(&uc2); 256} 257 258void 259_thr_ast(struct pthread *curthread) 260{ 261 262 if (!THR_IN_CRITICAL(curthread)) { 263 check_deferred_signal(curthread); 264 check_suspend(curthread); 265 check_cancel(curthread, NULL); 266 } 267} 268 269/* reschedule cancellation */ 270static void 271check_cancel(struct pthread *curthread, ucontext_t *ucp) 272{ 273 274 if (__predict_true(!curthread->cancel_pending || 275 !curthread->cancel_enable || curthread->no_cancel)) 276 return; 277 278 /* 279 * Otherwise, we are in defer mode, and we are at 280 * cancel point, tell kernel to not block the current 281 * thread on next cancelable system call. 282 * 283 * There are three cases we should call thr_wake() to 284 * turn on TDP_WAKEUP or send SIGCANCEL in kernel: 285 * 1) we are going to call a cancelable system call, 286 * non-zero cancel_point means we are already in 287 * cancelable state, next system call is cancelable. 288 * 2) because _thr_ast() may be called by 289 * THR_CRITICAL_LEAVE() which is used by rtld rwlock 290 * and any libthr internal locks, when rtld rwlock 291 * is used, it is mostly caused my an unresolved PLT. 292 * those routines may clear the TDP_WAKEUP flag by 293 * invoking some system calls, in those cases, we 294 * also should reenable the flag. 295 * 3) thread is in sigsuspend(), and the syscall insists 296 * on getting a signal before it agrees to return. 297 */ 298 if (curthread->cancel_point) { 299 if (curthread->in_sigsuspend && ucp) { 300 SIGADDSET(ucp->uc_sigmask, SIGCANCEL); 301 curthread->unblock_sigcancel = 1; 302 _thr_send_sig(curthread, SIGCANCEL); 303 } else 304 thr_wake(curthread->tid); 305 } else if (curthread->cancel_async) { 306 /* 307 * asynchronous cancellation mode, act upon 308 * immediately. 309 */ 310 _pthread_exit_mask(PTHREAD_CANCELED, 311 ucp? &ucp->uc_sigmask : NULL); 312 } 313} 314 315static void 316check_deferred_signal(struct pthread *curthread) 317{ 318 ucontext_t *uc; 319 struct sigaction act; 320 siginfo_t info; 321 322 if (__predict_true(curthread->deferred_siginfo.si_signo == 0)) 323 return; 324 325#if defined(__amd64__) || defined(__i386__) 326 uc = alloca(__getcontextx_size()); 327 __fillcontextx((char *)uc); 328#else 329 ucontext_t ucv; 330 uc = &ucv; 331 getcontext(uc); 332#endif 333 if (curthread->deferred_siginfo.si_signo != 0) { 334 act = curthread->deferred_sigact; 335 uc->uc_sigmask = curthread->deferred_sigmask; 336 memcpy(&info, &curthread->deferred_siginfo, sizeof(siginfo_t)); 337 /* remove signal */ 338 curthread->deferred_siginfo.si_signo = 0; 339 handle_signal(&act, info.si_signo, &info, uc); 340 } 341} 342 343static void 344check_suspend(struct pthread *curthread) 345{ 346 uint32_t cycle; 347 348 if (__predict_true((curthread->flags & 349 (THR_FLAGS_NEED_SUSPEND | THR_FLAGS_SUSPENDED)) 350 != THR_FLAGS_NEED_SUSPEND)) 351 return; 352 if (curthread == _single_thread) 353 return; 354 if (curthread->force_exit) 355 return; 356 357 /* 358 * Blocks SIGCANCEL which other threads must send. 359 */ 360 _thr_signal_block(curthread); 361 362 /* 363 * Increase critical_count, here we don't use THR_LOCK/UNLOCK 364 * because we are leaf code, we don't want to recursively call 365 * ourself. 366 */ 367 curthread->critical_count++; 368 THR_UMUTEX_LOCK(curthread, &(curthread)->lock); 369 while ((curthread->flags & (THR_FLAGS_NEED_SUSPEND | 370 THR_FLAGS_SUSPENDED)) == THR_FLAGS_NEED_SUSPEND) { 371 curthread->cycle++; 372 cycle = curthread->cycle; 373 374 /* Wake the thread suspending us. */ 375 _thr_umtx_wake(&curthread->cycle, INT_MAX, 0); 376 377 /* 378 * if we are from pthread_exit, we don't want to 379 * suspend, just go and die. 380 */ 381 if (curthread->state == PS_DEAD) 382 break; 383 curthread->flags |= THR_FLAGS_SUSPENDED; 384 THR_UMUTEX_UNLOCK(curthread, &(curthread)->lock); 385 _thr_umtx_wait_uint(&curthread->cycle, cycle, NULL, 0); 386 THR_UMUTEX_LOCK(curthread, &(curthread)->lock); 387 curthread->flags &= ~THR_FLAGS_SUSPENDED; 388 } 389 THR_UMUTEX_UNLOCK(curthread, &(curthread)->lock); 390 curthread->critical_count--; 391 392 _thr_signal_unblock(curthread); 393} 394 395void 396_thr_signal_init(void) 397{ 398 struct sigaction act; 399 400 /* Install SIGCANCEL handler. */ 401 SIGFILLSET(act.sa_mask); 402 act.sa_flags = SA_SIGINFO; 403 act.sa_sigaction = (__siginfohandler_t *)&sigcancel_handler; 404 __sys_sigaction(SIGCANCEL, &act, NULL); 405 406 /* Unblock SIGCANCEL */ 407 SIGEMPTYSET(act.sa_mask); 408 SIGADDSET(act.sa_mask, SIGCANCEL); 409 __sys_sigprocmask(SIG_UNBLOCK, &act.sa_mask, NULL); 410} 411 412void 413_thr_sigact_unload(struct dl_phdr_info *phdr_info) 414{ 415#if 0 416 struct pthread *curthread = _get_curthread(); 417 struct urwlock *rwlp; 418 struct sigaction *actp; 419 struct sigaction kact; 420 void (*handler)(int); 421 int sig; 422 423 _thr_signal_block(curthread); 424 for (sig = 1; sig <= _SIG_MAXSIG; sig++) { 425 actp = &_thr_sigact[sig-1].sigact; 426retry: 427 handler = actp->sa_handler; 428 if (handler != SIG_DFL && handler != SIG_IGN && 429 __elf_phdr_match_addr(phdr_info, handler)) { 430 rwlp = &_thr_sigact[sig-1].lock; 431 _thr_rwl_wrlock(rwlp); 432 if (handler != actp->sa_handler) { 433 _thr_rwl_unlock(rwlp); 434 goto retry; 435 } 436 actp->sa_handler = SIG_DFL; 437 actp->sa_flags = SA_SIGINFO; 438 SIGEMPTYSET(actp->sa_mask); 439 if (__sys_sigaction(sig, NULL, &kact) == 0 && 440 kact.sa_handler != SIG_DFL && 441 kact.sa_handler != SIG_IGN) 442 __sys_sigaction(sig, actp, NULL); 443 _thr_rwl_unlock(rwlp); 444 } 445 } 446 _thr_signal_unblock(curthread); 447#endif 448} 449 450void 451_thr_signal_prefork(void) 452{ 453 int i; 454 455 for (i = 1; i <= _SIG_MAXSIG; ++i) 456 _thr_rwl_rdlock(&_thr_sigact[i-1].lock); 457} 458 459void 460_thr_signal_postfork(void) 461{ 462 int i; 463 464 for (i = 1; i <= _SIG_MAXSIG; ++i) 465 _thr_rwl_unlock(&_thr_sigact[i-1].lock); 466} 467 468void 469_thr_signal_postfork_child(void) 470{ 471 int i; 472 473 for (i = 1; i <= _SIG_MAXSIG; ++i) 474 bzero(&_thr_sigact[i-1].lock, sizeof(struct urwlock)); 475} 476 477void 478_thr_signal_deinit(void) 479{ 480} 481 482__weak_reference(___pause, pause); 483 484int 485___pause(void) 486{ 487 sigset_t oset; 488 489 if (_sigprocmask(SIG_BLOCK, NULL, &oset) == -1) 490 return (-1); 491 return (__sigsuspend(&oset)); 492} 493 494__weak_reference(_raise, raise); 495 496int 497_raise(int sig) 498{ 499 return _thr_send_sig(_get_curthread(), sig); 500} 501 502__weak_reference(_sigaction, sigaction); 503 504int 505_sigaction(int sig, const struct sigaction * act, struct sigaction * oact) 506{ 507 struct sigaction newact, oldact, oldact2; 508 sigset_t oldset; 509 int ret = 0, err = 0; 510 511 if (!_SIG_VALID(sig) || sig == SIGCANCEL) { 512 errno = EINVAL; 513 return (-1); 514 } 515 516 if (act) 517 newact = *act; 518 519 __sys_sigprocmask(SIG_SETMASK, &_thr_maskset, &oldset); 520 _thr_rwl_wrlock(&_thr_sigact[sig-1].lock); 521 522 if (act != NULL) { 523 oldact2 = _thr_sigact[sig-1].sigact; 524 525 /* 526 * if a new sig handler is SIG_DFL or SIG_IGN, 527 * don't remove old handler from _thr_sigact[], 528 * so deferred signals still can use the handlers, 529 * multiple threads invoking sigaction itself is 530 * a race condition, so it is not a problem. 531 */ 532 if (newact.sa_handler != SIG_DFL && 533 newact.sa_handler != SIG_IGN) { 534 _thr_sigact[sig-1].sigact = newact; 535 remove_thr_signals( 536 &_thr_sigact[sig-1].sigact.sa_mask); 537 newact.sa_flags &= ~SA_NODEFER; 538 newact.sa_flags |= SA_SIGINFO; 539 newact.sa_sigaction = thr_sighandler; 540 newact.sa_mask = _thr_maskset; /* mask all signals */ 541 } 542 if ((ret = __sys_sigaction(sig, &newact, &oldact))) { 543 err = errno; 544 _thr_sigact[sig-1].sigact = oldact2; 545 } 546 } else if (oact != NULL) { 547 ret = __sys_sigaction(sig, NULL, &oldact); 548 err = errno; 549 } 550 551 if (oldact.sa_handler != SIG_DFL && 552 oldact.sa_handler != SIG_IGN) { 553 if (act != NULL) 554 oldact = oldact2; 555 else if (oact != NULL) 556 oldact = _thr_sigact[sig-1].sigact; 557 } 558 559 _thr_rwl_unlock(&_thr_sigact[sig-1].lock); 560 __sys_sigprocmask(SIG_SETMASK, &oldset, NULL); 561 562 if (ret == 0) { 563 if (oact != NULL) 564 *oact = oldact; 565 } else { 566 errno = err; 567 } 568 return (ret); 569} 570 571__weak_reference(_sigprocmask, sigprocmask); 572 573int 574_sigprocmask(int how, const sigset_t *set, sigset_t *oset) 575{ 576 const sigset_t *p = set; 577 sigset_t newset; 578 579 if (how != SIG_UNBLOCK) { 580 if (set != NULL) { 581 newset = *set; 582 SIGDELSET(newset, SIGCANCEL); 583 p = &newset; 584 } 585 } 586 return (__sys_sigprocmask(how, p, oset)); 587} 588 589__weak_reference(_pthread_sigmask, pthread_sigmask); 590 591int 592_pthread_sigmask(int how, const sigset_t *set, sigset_t *oset) 593{ 594 if (_sigprocmask(how, set, oset)) 595 return (errno); 596 return (0); 597} 598 599__weak_reference(__sigsuspend, sigsuspend); 600 601int 602_sigsuspend(const sigset_t * set) 603{ 604 sigset_t newset; 605 606 return (__sys_sigsuspend(thr_remove_thr_signals(set, &newset))); 607} 608 609int 610__sigsuspend(const sigset_t * set) 611{ 612 struct pthread *curthread; 613 sigset_t newset; 614 int ret, old; 615 616 curthread = _get_curthread(); 617 618 old = curthread->in_sigsuspend; 619 curthread->in_sigsuspend = 1; 620 _thr_cancel_enter(curthread); 621 ret = __sys_sigsuspend(thr_remove_thr_signals(set, &newset)); 622 _thr_cancel_leave(curthread, 1); 623 curthread->in_sigsuspend = old; 624 if (curthread->unblock_sigcancel) { 625 curthread->unblock_sigcancel = 0; 626 SIGEMPTYSET(newset); 627 SIGADDSET(newset, SIGCANCEL); 628 __sys_sigprocmask(SIG_UNBLOCK, &newset, NULL); 629 } 630 631 return (ret); 632} 633 634__weak_reference(___sigwait, sigwait); 635__weak_reference(__sigtimedwait, sigtimedwait); 636__weak_reference(__sigwaitinfo, sigwaitinfo); 637 638int 639_sigtimedwait(const sigset_t *set, siginfo_t *info, 640 const struct timespec * timeout) 641{ 642 sigset_t newset; 643 644 return (__sys_sigtimedwait(thr_remove_thr_signals(set, &newset), info, 645 timeout)); 646} 647 648/* 649 * Cancellation behavior: 650 * Thread may be canceled at start, if thread got signal, 651 * it is not canceled. 652 */ 653int 654__sigtimedwait(const sigset_t *set, siginfo_t *info, 655 const struct timespec * timeout) 656{ 657 struct pthread *curthread = _get_curthread(); 658 sigset_t newset; 659 int ret; 660 661 _thr_cancel_enter(curthread); 662 ret = __sys_sigtimedwait(thr_remove_thr_signals(set, &newset), info, 663 timeout); 664 _thr_cancel_leave(curthread, (ret == -1)); 665 return (ret); 666} 667 668int 669_sigwaitinfo(const sigset_t *set, siginfo_t *info) 670{ 671 sigset_t newset; 672 673 return (__sys_sigwaitinfo(thr_remove_thr_signals(set, &newset), info)); 674} 675 676/* 677 * Cancellation behavior: 678 * Thread may be canceled at start, if thread got signal, 679 * it is not canceled. 680 */ 681int 682__sigwaitinfo(const sigset_t *set, siginfo_t *info) 683{ 684 struct pthread *curthread = _get_curthread(); 685 sigset_t newset; 686 int ret; 687 688 _thr_cancel_enter(curthread); 689 ret = __sys_sigwaitinfo(thr_remove_thr_signals(set, &newset), info); 690 _thr_cancel_leave(curthread, ret == -1); 691 return (ret); 692} 693 694int 695_sigwait(const sigset_t *set, int *sig) 696{ 697 sigset_t newset; 698 699 return (__sys_sigwait(thr_remove_thr_signals(set, &newset), sig)); 700} 701 702/* 703 * Cancellation behavior: 704 * Thread may be canceled at start, if thread got signal, 705 * it is not canceled. 706 */ 707int 708___sigwait(const sigset_t *set, int *sig) 709{ 710 struct pthread *curthread = _get_curthread(); 711 sigset_t newset; 712 int ret; 713 714 do { 715 _thr_cancel_enter(curthread); 716 ret = __sys_sigwait(thr_remove_thr_signals(set, &newset), sig); 717 _thr_cancel_leave(curthread, (ret != 0)); 718 } while (ret == EINTR); 719 return (ret); 720} 721 722__weak_reference(_setcontext, setcontext); 723int 724_setcontext(const ucontext_t *ucp) 725{ 726 ucontext_t uc; 727 728 if (ucp == NULL) 729 return (EINVAL); 730 if (!SIGISMEMBER(uc.uc_sigmask, SIGCANCEL)) 731 return __sys_setcontext(ucp); 732 (void) memcpy(&uc, ucp, sizeof(uc)); 733 SIGDELSET(uc.uc_sigmask, SIGCANCEL); 734 return __sys_setcontext(&uc); 735} 736 737__weak_reference(_swapcontext, swapcontext); 738int 739_swapcontext(ucontext_t *oucp, const ucontext_t *ucp) 740{ 741 ucontext_t uc; 742 743 if (oucp == NULL || ucp == NULL) 744 return (EINVAL); 745 if (SIGISMEMBER(ucp->uc_sigmask, SIGCANCEL)) { 746 (void) memcpy(&uc, ucp, sizeof(uc)); 747 SIGDELSET(uc.uc_sigmask, SIGCANCEL); 748 ucp = &uc; 749 } 750 return __sys_swapcontext(oucp, ucp); 751} 752