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 * $FreeBSD$ 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 50 struct usigaction { 51 struct sigaction sigact; 52 struct urwlock lock; 53 }; 54 55 static struct usigaction _thr_sigact[_SIG_MAXSIG]; 56 57 static void thr_sighandler(int, siginfo_t *, void *); 58 static void handle_signal(struct sigaction *, int, siginfo_t *, ucontext_t *); 59 static void check_deferred_signal(struct pthread *); 60 static void check_suspend(struct pthread *); 61 static void check_cancel(struct pthread *curthread, ucontext_t *ucp); 62 63 int ___pause(void); 64 int _raise(int); 65 int __sigtimedwait(const sigset_t *set, siginfo_t *info, 66 const struct timespec * timeout); 67 int _sigtimedwait(const sigset_t *set, siginfo_t *info, 68 const struct timespec * timeout); 69 int __sigwaitinfo(const sigset_t *set, siginfo_t *info); 70 int _sigwaitinfo(const sigset_t *set, siginfo_t *info); 71 int ___sigwait(const sigset_t *set, int *sig); 72 int _sigwait(const sigset_t *set, int *sig); 73 int __sigsuspend(const sigset_t *sigmask); 74 int _sigaction(int, const struct sigaction *, struct sigaction *); 75 int _setcontext(const ucontext_t *); 76 int _swapcontext(ucontext_t *, const ucontext_t *); 77 78 static 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 85 static const sigset_t _thr_maskset={{ 86 0xffffffff, 87 0xffffffff, 88 0xffffffff, 89 0xffffffff}}; 90 91 void 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 } 102 103 void 104 _thr_signal_unblock(struct pthread *curthread) 105 { 106 if (--curthread->sigblock == 0) 107 __sys_sigprocmask(SIG_SETMASK, &curthread->sigmask, NULL); 108 } 109 110 int 111 _thr_send_sig(struct pthread *thread, int sig) 112 { 113 return thr_kill(thread->tid, sig); 114 } 115 116 static inline void 117 remove_thr_signals(sigset_t *set) 118 { 119 if (SIGISMEMBER(*set, SIGCANCEL)) 120 SIGDELSET(*set, SIGCANCEL); 121 } 122 123 static const sigset_t * 124 thr_remove_thr_signals(const sigset_t *set, sigset_t *newset) 125 { 126 *newset = *set; 127 remove_thr_signals(newset); 128 return (newset); 129 } 130 131 static void 132 sigcancel_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 } 145 146 typedef 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 */ 152 static void 153 thr_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 } 184 185 static void 186 handle_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, there 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 } 257 258 void 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 */ 270 static void 271 check_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 } 314 315 static void 316 check_deferred_signal(struct pthread *curthread) 317 { 318 ucontext_t *uc; 319 struct sigaction act; 320 siginfo_t info; 321 int uc_len; 322 323 if (__predict_true(curthread->deferred_siginfo.si_signo == 0)) 324 return; 325 326 uc_len = __getcontextx_size(); 327 uc = alloca(uc_len); 328 getcontext(uc); 329 if (curthread->deferred_siginfo.si_signo == 0) 330 return; 331 __fillcontextx2((char *)uc); 332 act = curthread->deferred_sigact; 333 uc->uc_sigmask = curthread->deferred_sigmask; 334 memcpy(&info, &curthread->deferred_siginfo, sizeof(siginfo_t)); 335 /* remove signal */ 336 curthread->deferred_siginfo.si_signo = 0; 337 handle_signal(&act, info.si_signo, &info, uc); 338 } 339 340 static void 341 check_suspend(struct pthread *curthread) 342 { 343 uint32_t cycle; 344 345 if (__predict_true((curthread->flags & 346 (THR_FLAGS_NEED_SUSPEND | THR_FLAGS_SUSPENDED)) 347 != THR_FLAGS_NEED_SUSPEND)) 348 return; 349 if (curthread == _single_thread) 350 return; 351 if (curthread->force_exit) 352 return; 353 354 /* 355 * Blocks SIGCANCEL which other threads must send. 356 */ 357 _thr_signal_block(curthread); 358 359 /* 360 * Increase critical_count, here we don't use THR_LOCK/UNLOCK 361 * because we are leaf code, we don't want to recursively call 362 * ourself. 363 */ 364 curthread->critical_count++; 365 THR_UMUTEX_LOCK(curthread, &(curthread)->lock); 366 while ((curthread->flags & (THR_FLAGS_NEED_SUSPEND | 367 THR_FLAGS_SUSPENDED)) == THR_FLAGS_NEED_SUSPEND) { 368 curthread->cycle++; 369 cycle = curthread->cycle; 370 371 /* Wake the thread suspending us. */ 372 _thr_umtx_wake(&curthread->cycle, INT_MAX, 0); 373 374 /* 375 * if we are from pthread_exit, we don't want to 376 * suspend, just go and die. 377 */ 378 if (curthread->state == PS_DEAD) 379 break; 380 curthread->flags |= THR_FLAGS_SUSPENDED; 381 THR_UMUTEX_UNLOCK(curthread, &(curthread)->lock); 382 _thr_umtx_wait_uint(&curthread->cycle, cycle, NULL, 0); 383 THR_UMUTEX_LOCK(curthread, &(curthread)->lock); 384 curthread->flags &= ~THR_FLAGS_SUSPENDED; 385 } 386 THR_UMUTEX_UNLOCK(curthread, &(curthread)->lock); 387 curthread->critical_count--; 388 389 _thr_signal_unblock(curthread); 390 } 391 392 void 393 _thr_signal_init(void) 394 { 395 struct sigaction act; 396 397 /* Install SIGCANCEL handler. */ 398 SIGFILLSET(act.sa_mask); 399 act.sa_flags = SA_SIGINFO; 400 act.sa_sigaction = (__siginfohandler_t *)&sigcancel_handler; 401 __sys_sigaction(SIGCANCEL, &act, NULL); 402 403 /* Unblock SIGCANCEL */ 404 SIGEMPTYSET(act.sa_mask); 405 SIGADDSET(act.sa_mask, SIGCANCEL); 406 __sys_sigprocmask(SIG_UNBLOCK, &act.sa_mask, NULL); 407 } 408 409 void 410 _thr_sigact_unload(struct dl_phdr_info *phdr_info) 411 { 412 #if 0 413 struct pthread *curthread = _get_curthread(); 414 struct urwlock *rwlp; 415 struct sigaction *actp; 416 struct sigaction kact; 417 void (*handler)(int); 418 int sig; 419 420 _thr_signal_block(curthread); 421 for (sig = 1; sig <= _SIG_MAXSIG; sig++) { 422 actp = &_thr_sigact[sig-1].sigact; 423 retry: 424 handler = actp->sa_handler; 425 if (handler != SIG_DFL && handler != SIG_IGN && 426 __elf_phdr_match_addr(phdr_info, handler)) { 427 rwlp = &_thr_sigact[sig-1].lock; 428 _thr_rwl_wrlock(rwlp); 429 if (handler != actp->sa_handler) { 430 _thr_rwl_unlock(rwlp); 431 goto retry; 432 } 433 actp->sa_handler = SIG_DFL; 434 actp->sa_flags = SA_SIGINFO; 435 SIGEMPTYSET(actp->sa_mask); 436 if (__sys_sigaction(sig, NULL, &kact) == 0 && 437 kact.sa_handler != SIG_DFL && 438 kact.sa_handler != SIG_IGN) 439 __sys_sigaction(sig, actp, NULL); 440 _thr_rwl_unlock(rwlp); 441 } 442 } 443 _thr_signal_unblock(curthread); 444 #endif 445 } 446 447 void 448 _thr_signal_prefork(void) 449 { 450 int i; 451 452 for (i = 1; i <= _SIG_MAXSIG; ++i) 453 _thr_rwl_rdlock(&_thr_sigact[i-1].lock); 454 } 455 456 void 457 _thr_signal_postfork(void) 458 { 459 int i; 460 461 for (i = 1; i <= _SIG_MAXSIG; ++i) 462 _thr_rwl_unlock(&_thr_sigact[i-1].lock); 463 } 464 465 void 466 _thr_signal_postfork_child(void) 467 { 468 int i; 469 470 for (i = 1; i <= _SIG_MAXSIG; ++i) 471 bzero(&_thr_sigact[i-1].lock, sizeof(struct urwlock)); 472 } 473 474 void 475 _thr_signal_deinit(void) 476 { 477 } 478 479 __weak_reference(___pause, pause); 480 481 int 482 ___pause(void) 483 { 484 sigset_t oset; 485 486 if (_sigprocmask(SIG_BLOCK, NULL, &oset) == -1) 487 return (-1); 488 return (__sigsuspend(&oset)); 489 } 490 491 __weak_reference(_raise, raise); 492 493 int 494 _raise(int sig) 495 { 496 return _thr_send_sig(_get_curthread(), sig); 497 } 498 499 __weak_reference(_sigaction, sigaction); 500 501 int 502 _sigaction(int sig, const struct sigaction * act, struct sigaction * oact) 503 { 504 struct sigaction newact, oldact, oldact2; 505 sigset_t oldset; 506 int ret = 0, err = 0; 507 508 if (!_SIG_VALID(sig) || sig == SIGCANCEL) { 509 errno = EINVAL; 510 return (-1); 511 } 512 513 if (act) 514 newact = *act; 515 516 __sys_sigprocmask(SIG_SETMASK, &_thr_maskset, &oldset); 517 _thr_rwl_wrlock(&_thr_sigact[sig-1].lock); 518 519 if (act != NULL) { 520 oldact2 = _thr_sigact[sig-1].sigact; 521 522 /* 523 * if a new sig handler is SIG_DFL or SIG_IGN, 524 * don't remove old handler from _thr_sigact[], 525 * so deferred signals still can use the handlers, 526 * multiple threads invoking sigaction itself is 527 * a race condition, so it is not a problem. 528 */ 529 if (newact.sa_handler != SIG_DFL && 530 newact.sa_handler != SIG_IGN) { 531 _thr_sigact[sig-1].sigact = newact; 532 remove_thr_signals( 533 &_thr_sigact[sig-1].sigact.sa_mask); 534 newact.sa_flags &= ~SA_NODEFER; 535 newact.sa_flags |= SA_SIGINFO; 536 newact.sa_sigaction = thr_sighandler; 537 newact.sa_mask = _thr_maskset; /* mask all signals */ 538 } 539 if ((ret = __sys_sigaction(sig, &newact, &oldact))) { 540 err = errno; 541 _thr_sigact[sig-1].sigact = oldact2; 542 } 543 } else if (oact != NULL) { 544 ret = __sys_sigaction(sig, NULL, &oldact); 545 err = errno; 546 } 547 548 if (oldact.sa_handler != SIG_DFL && 549 oldact.sa_handler != SIG_IGN) { 550 if (act != NULL) 551 oldact = oldact2; 552 else if (oact != NULL) 553 oldact = _thr_sigact[sig-1].sigact; 554 } 555 556 _thr_rwl_unlock(&_thr_sigact[sig-1].lock); 557 __sys_sigprocmask(SIG_SETMASK, &oldset, NULL); 558 559 if (ret == 0) { 560 if (oact != NULL) 561 *oact = oldact; 562 } else { 563 errno = err; 564 } 565 return (ret); 566 } 567 568 __weak_reference(_sigprocmask, sigprocmask); 569 570 int 571 _sigprocmask(int how, const sigset_t *set, sigset_t *oset) 572 { 573 const sigset_t *p = set; 574 sigset_t newset; 575 576 if (how != SIG_UNBLOCK) { 577 if (set != NULL) { 578 newset = *set; 579 SIGDELSET(newset, SIGCANCEL); 580 p = &newset; 581 } 582 } 583 return (__sys_sigprocmask(how, p, oset)); 584 } 585 586 __weak_reference(_pthread_sigmask, pthread_sigmask); 587 588 int 589 _pthread_sigmask(int how, const sigset_t *set, sigset_t *oset) 590 { 591 if (_sigprocmask(how, set, oset)) 592 return (errno); 593 return (0); 594 } 595 596 __weak_reference(__sigsuspend, sigsuspend); 597 598 int 599 _sigsuspend(const sigset_t * set) 600 { 601 sigset_t newset; 602 603 return (__sys_sigsuspend(thr_remove_thr_signals(set, &newset))); 604 } 605 606 int 607 __sigsuspend(const sigset_t * set) 608 { 609 struct pthread *curthread; 610 sigset_t newset; 611 int ret, old; 612 613 curthread = _get_curthread(); 614 615 old = curthread->in_sigsuspend; 616 curthread->in_sigsuspend = 1; 617 _thr_cancel_enter(curthread); 618 ret = __sys_sigsuspend(thr_remove_thr_signals(set, &newset)); 619 _thr_cancel_leave(curthread, 1); 620 curthread->in_sigsuspend = old; 621 if (curthread->unblock_sigcancel) { 622 curthread->unblock_sigcancel = 0; 623 SIGEMPTYSET(newset); 624 SIGADDSET(newset, SIGCANCEL); 625 __sys_sigprocmask(SIG_UNBLOCK, &newset, NULL); 626 } 627 628 return (ret); 629 } 630 631 __weak_reference(___sigwait, sigwait); 632 __weak_reference(__sigtimedwait, sigtimedwait); 633 __weak_reference(__sigwaitinfo, sigwaitinfo); 634 635 int 636 _sigtimedwait(const sigset_t *set, siginfo_t *info, 637 const struct timespec * timeout) 638 { 639 sigset_t newset; 640 641 return (__sys_sigtimedwait(thr_remove_thr_signals(set, &newset), info, 642 timeout)); 643 } 644 645 /* 646 * Cancellation behavior: 647 * Thread may be canceled at start, if thread got signal, 648 * it is not canceled. 649 */ 650 int 651 __sigtimedwait(const sigset_t *set, siginfo_t *info, 652 const struct timespec * timeout) 653 { 654 struct pthread *curthread = _get_curthread(); 655 sigset_t newset; 656 int ret; 657 658 _thr_cancel_enter(curthread); 659 ret = __sys_sigtimedwait(thr_remove_thr_signals(set, &newset), info, 660 timeout); 661 _thr_cancel_leave(curthread, (ret == -1)); 662 return (ret); 663 } 664 665 int 666 _sigwaitinfo(const sigset_t *set, siginfo_t *info) 667 { 668 sigset_t newset; 669 670 return (__sys_sigwaitinfo(thr_remove_thr_signals(set, &newset), info)); 671 } 672 673 /* 674 * Cancellation behavior: 675 * Thread may be canceled at start, if thread got signal, 676 * it is not canceled. 677 */ 678 int 679 __sigwaitinfo(const sigset_t *set, siginfo_t *info) 680 { 681 struct pthread *curthread = _get_curthread(); 682 sigset_t newset; 683 int ret; 684 685 _thr_cancel_enter(curthread); 686 ret = __sys_sigwaitinfo(thr_remove_thr_signals(set, &newset), info); 687 _thr_cancel_leave(curthread, ret == -1); 688 return (ret); 689 } 690 691 int 692 _sigwait(const sigset_t *set, int *sig) 693 { 694 sigset_t newset; 695 696 return (__sys_sigwait(thr_remove_thr_signals(set, &newset), sig)); 697 } 698 699 /* 700 * Cancellation behavior: 701 * Thread may be canceled at start, if thread got signal, 702 * it is not canceled. 703 */ 704 int 705 ___sigwait(const sigset_t *set, int *sig) 706 { 707 struct pthread *curthread = _get_curthread(); 708 sigset_t newset; 709 int ret; 710 711 do { 712 _thr_cancel_enter(curthread); 713 ret = __sys_sigwait(thr_remove_thr_signals(set, &newset), sig); 714 _thr_cancel_leave(curthread, (ret != 0)); 715 } while (ret == EINTR); 716 return (ret); 717 } 718 719 __weak_reference(_setcontext, setcontext); 720 int 721 _setcontext(const ucontext_t *ucp) 722 { 723 ucontext_t uc; 724 725 if (ucp == NULL) { 726 errno = EINVAL; 727 return (-1); 728 } 729 if (!SIGISMEMBER(uc.uc_sigmask, SIGCANCEL)) 730 return __sys_setcontext(ucp); 731 (void) memcpy(&uc, ucp, sizeof(uc)); 732 SIGDELSET(uc.uc_sigmask, SIGCANCEL); 733 return __sys_setcontext(&uc); 734 } 735 736 __weak_reference(_swapcontext, swapcontext); 737 int 738 _swapcontext(ucontext_t *oucp, const ucontext_t *ucp) 739 { 740 ucontext_t uc; 741 742 if (oucp == NULL || ucp == NULL) { 743 errno = EINVAL; 744 return (-1); 745 } 746 if (SIGISMEMBER(ucp->uc_sigmask, SIGCANCEL)) { 747 (void) memcpy(&uc, ucp, sizeof(uc)); 748 SIGDELSET(uc.uc_sigmask, SIGCANCEL); 749 ucp = &uc; 750 } 751 return __sys_swapcontext(oucp, ucp); 752 } 753