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 curthread->deferred_run = 0; 166 167 /* 168 * if a thread is in critical region, for example it holds low level locks, 169 * try to defer the signal processing, however if the signal is synchronous 170 * signal, it means a bad thing has happened, this is a programming error, 171 * resuming fault point can not help anything (normally causes deadloop), 172 * so here we let user code handle it immediately. 173 */ 174 if (THR_IN_CRITICAL(curthread) && SIGISMEMBER(_thr_deferset, sig)) { 175 memcpy(&curthread->deferred_sigact, &act, sizeof(struct sigaction)); 176 memcpy(&curthread->deferred_siginfo, info, sizeof(siginfo_t)); 177 curthread->deferred_sigmask = ucp->uc_sigmask; 178 /* mask all signals, we will restore it later. */ 179 ucp->uc_sigmask = _thr_deferset; 180 return; 181 } 182 183 handle_signal(&act, sig, info, ucp); 184 } 185 186 static void 187 handle_signal(struct sigaction *actp, int sig, siginfo_t *info, ucontext_t *ucp) 188 { 189 struct pthread *curthread = _get_curthread(); 190 ucontext_t uc2; 191 __siginfohandler_t *sigfunc; 192 int cancel_point; 193 int cancel_async; 194 int cancel_enable; 195 int in_sigsuspend; 196 int err; 197 198 /* add previous level mask */ 199 SIGSETOR(actp->sa_mask, ucp->uc_sigmask); 200 201 /* add this signal's mask */ 202 if (!(actp->sa_flags & SA_NODEFER)) 203 SIGADDSET(actp->sa_mask, sig); 204 205 in_sigsuspend = curthread->in_sigsuspend; 206 curthread->in_sigsuspend = 0; 207 208 /* 209 * If thread is in deferred cancellation mode, disable cancellation 210 * in signal handler. 211 * If user signal handler calls a cancellation point function, e.g, 212 * it calls write() to write data to file, because write() is a 213 * cancellation point, the thread is immediately cancelled if 214 * cancellation is pending, to avoid this problem while thread is in 215 * deferring mode, cancellation is temporarily disabled. 216 */ 217 cancel_point = curthread->cancel_point; 218 cancel_async = curthread->cancel_async; 219 cancel_enable = curthread->cancel_enable; 220 curthread->cancel_point = 0; 221 if (!cancel_async) 222 curthread->cancel_enable = 0; 223 224 /* restore correct mask before calling user handler */ 225 __sys_sigprocmask(SIG_SETMASK, &actp->sa_mask, NULL); 226 227 sigfunc = actp->sa_sigaction; 228 229 /* 230 * We have already reset cancellation point flags, so if user's code 231 * longjmp()s out of its signal handler, wish its jmpbuf was set 232 * outside of a cancellation point, in most cases, this would be 233 * true. However, there is no way to save cancel_enable in jmpbuf, 234 * so after setjmps() returns once more, the user code may need to 235 * re-set cancel_enable flag by calling pthread_setcancelstate(). 236 */ 237 if ((actp->sa_flags & SA_SIGINFO) != 0) 238 (*(sigfunc))(sig, info, ucp); 239 else { 240 ((ohandler)(*sigfunc))( 241 sig, info->si_code, (struct sigcontext *)ucp, 242 info->si_addr, (__sighandler_t *)sigfunc); 243 } 244 err = errno; 245 246 curthread->in_sigsuspend = in_sigsuspend; 247 curthread->cancel_point = cancel_point; 248 curthread->cancel_enable = cancel_enable; 249 250 memcpy(&uc2, ucp, sizeof(uc2)); 251 SIGDELSET(uc2.uc_sigmask, SIGCANCEL); 252 253 /* reschedule cancellation */ 254 check_cancel(curthread, &uc2); 255 errno = err; 256 __sys_sigreturn(&uc2); 257 } 258 259 void 260 _thr_ast(struct pthread *curthread) 261 { 262 263 if (!THR_IN_CRITICAL(curthread)) { 264 check_deferred_signal(curthread); 265 check_suspend(curthread); 266 check_cancel(curthread, NULL); 267 } 268 } 269 270 /* reschedule cancellation */ 271 static void 272 check_cancel(struct pthread *curthread, ucontext_t *ucp) 273 { 274 275 if (__predict_true(!curthread->cancel_pending || 276 !curthread->cancel_enable || curthread->no_cancel)) 277 return; 278 279 /* 280 * Otherwise, we are in defer mode, and we are at 281 * cancel point, tell kernel to not block the current 282 * thread on next cancelable system call. 283 * 284 * There are three cases we should call thr_wake() to 285 * turn on TDP_WAKEUP or send SIGCANCEL in kernel: 286 * 1) we are going to call a cancelable system call, 287 * non-zero cancel_point means we are already in 288 * cancelable state, next system call is cancelable. 289 * 2) because _thr_ast() may be called by 290 * THR_CRITICAL_LEAVE() which is used by rtld rwlock 291 * and any libthr internal locks, when rtld rwlock 292 * is used, it is mostly caused my an unresolved PLT. 293 * those routines may clear the TDP_WAKEUP flag by 294 * invoking some system calls, in those cases, we 295 * also should reenable the flag. 296 * 3) thread is in sigsuspend(), and the syscall insists 297 * on getting a signal before it agrees to return. 298 */ 299 if (curthread->cancel_point) { 300 if (curthread->in_sigsuspend && ucp) { 301 SIGADDSET(ucp->uc_sigmask, SIGCANCEL); 302 curthread->unblock_sigcancel = 1; 303 _thr_send_sig(curthread, SIGCANCEL); 304 } else 305 thr_wake(curthread->tid); 306 } else if (curthread->cancel_async) { 307 /* 308 * asynchronous cancellation mode, act upon 309 * immediately. 310 */ 311 _pthread_exit_mask(PTHREAD_CANCELED, 312 ucp? &ucp->uc_sigmask : NULL); 313 } 314 } 315 316 static void 317 check_deferred_signal(struct pthread *curthread) 318 { 319 ucontext_t *uc; 320 struct sigaction act; 321 siginfo_t info; 322 int uc_len; 323 324 if (__predict_true(curthread->deferred_siginfo.si_signo == 0 || 325 curthread->deferred_run)) 326 return; 327 328 curthread->deferred_run = 1; 329 uc_len = __getcontextx_size(); 330 uc = alloca(uc_len); 331 getcontext(uc); 332 if (curthread->deferred_siginfo.si_signo == 0) { 333 curthread->deferred_run = 0; 334 return; 335 } 336 __fillcontextx2((char *)uc); 337 act = curthread->deferred_sigact; 338 uc->uc_sigmask = curthread->deferred_sigmask; 339 memcpy(&info, &curthread->deferred_siginfo, sizeof(siginfo_t)); 340 /* remove signal */ 341 curthread->deferred_siginfo.si_signo = 0; 342 handle_signal(&act, info.si_signo, &info, uc); 343 } 344 345 static void 346 check_suspend(struct pthread *curthread) 347 { 348 uint32_t cycle; 349 350 if (__predict_true((curthread->flags & 351 (THR_FLAGS_NEED_SUSPEND | THR_FLAGS_SUSPENDED)) 352 != THR_FLAGS_NEED_SUSPEND)) 353 return; 354 if (curthread == _single_thread) 355 return; 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 } 396 397 void 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 } 413 414 void 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; 428 retry: 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 } 451 452 void 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 } 460 461 void 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 } 469 470 void 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 } 478 479 void 480 _thr_signal_deinit(void) 481 { 482 } 483 484 __weak_reference(___pause, pause); 485 486 int 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); 497 498 int 499 _raise(int sig) 500 { 501 return _thr_send_sig(_get_curthread(), sig); 502 } 503 504 __weak_reference(_sigaction, sigaction); 505 506 int 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 if (act != NULL) 556 oldact = oldact2; 557 else if (oact != NULL) 558 oldact = _thr_sigact[sig-1].sigact; 559 } 560 561 _thr_rwl_unlock(&_thr_sigact[sig-1].lock); 562 __sys_sigprocmask(SIG_SETMASK, &oldset, NULL); 563 564 if (ret == 0) { 565 if (oact != NULL) 566 *oact = oldact; 567 } else { 568 errno = err; 569 } 570 return (ret); 571 } 572 573 __weak_reference(_sigprocmask, sigprocmask); 574 575 int 576 _sigprocmask(int how, const sigset_t *set, sigset_t *oset) 577 { 578 const sigset_t *p = set; 579 sigset_t newset; 580 581 if (how != SIG_UNBLOCK) { 582 if (set != NULL) { 583 newset = *set; 584 SIGDELSET(newset, SIGCANCEL); 585 p = &newset; 586 } 587 } 588 return (__sys_sigprocmask(how, p, oset)); 589 } 590 591 __weak_reference(_pthread_sigmask, pthread_sigmask); 592 593 int 594 _pthread_sigmask(int how, const sigset_t *set, sigset_t *oset) 595 { 596 if (_sigprocmask(how, set, oset)) 597 return (errno); 598 return (0); 599 } 600 601 __weak_reference(__sigsuspend, sigsuspend); 602 603 int 604 _sigsuspend(const sigset_t * set) 605 { 606 sigset_t newset; 607 608 return (__sys_sigsuspend(thr_remove_thr_signals(set, &newset))); 609 } 610 611 int 612 __sigsuspend(const sigset_t * set) 613 { 614 struct pthread *curthread; 615 sigset_t newset; 616 int ret, old; 617 618 curthread = _get_curthread(); 619 620 old = curthread->in_sigsuspend; 621 curthread->in_sigsuspend = 1; 622 _thr_cancel_enter(curthread); 623 ret = __sys_sigsuspend(thr_remove_thr_signals(set, &newset)); 624 _thr_cancel_leave(curthread, 1); 625 curthread->in_sigsuspend = old; 626 if (curthread->unblock_sigcancel) { 627 curthread->unblock_sigcancel = 0; 628 SIGEMPTYSET(newset); 629 SIGADDSET(newset, SIGCANCEL); 630 __sys_sigprocmask(SIG_UNBLOCK, &newset, NULL); 631 } 632 633 return (ret); 634 } 635 636 __weak_reference(___sigwait, sigwait); 637 __weak_reference(__sigtimedwait, sigtimedwait); 638 __weak_reference(__sigwaitinfo, sigwaitinfo); 639 640 int 641 _sigtimedwait(const sigset_t *set, siginfo_t *info, 642 const struct timespec * timeout) 643 { 644 sigset_t newset; 645 646 return (__sys_sigtimedwait(thr_remove_thr_signals(set, &newset), info, 647 timeout)); 648 } 649 650 /* 651 * Cancellation behavior: 652 * Thread may be canceled at start, if thread got signal, 653 * it is not canceled. 654 */ 655 int 656 __sigtimedwait(const sigset_t *set, siginfo_t *info, 657 const struct timespec * timeout) 658 { 659 struct pthread *curthread = _get_curthread(); 660 sigset_t newset; 661 int ret; 662 663 _thr_cancel_enter(curthread); 664 ret = __sys_sigtimedwait(thr_remove_thr_signals(set, &newset), info, 665 timeout); 666 _thr_cancel_leave(curthread, (ret == -1)); 667 return (ret); 668 } 669 670 int 671 _sigwaitinfo(const sigset_t *set, siginfo_t *info) 672 { 673 sigset_t newset; 674 675 return (__sys_sigwaitinfo(thr_remove_thr_signals(set, &newset), info)); 676 } 677 678 /* 679 * Cancellation behavior: 680 * Thread may be canceled at start, if thread got signal, 681 * it is not canceled. 682 */ 683 int 684 __sigwaitinfo(const sigset_t *set, siginfo_t *info) 685 { 686 struct pthread *curthread = _get_curthread(); 687 sigset_t newset; 688 int ret; 689 690 _thr_cancel_enter(curthread); 691 ret = __sys_sigwaitinfo(thr_remove_thr_signals(set, &newset), info); 692 _thr_cancel_leave(curthread, ret == -1); 693 return (ret); 694 } 695 696 int 697 _sigwait(const sigset_t *set, int *sig) 698 { 699 sigset_t newset; 700 701 return (__sys_sigwait(thr_remove_thr_signals(set, &newset), sig)); 702 } 703 704 /* 705 * Cancellation behavior: 706 * Thread may be canceled at start, if thread got signal, 707 * it is not canceled. 708 */ 709 int 710 ___sigwait(const sigset_t *set, int *sig) 711 { 712 struct pthread *curthread = _get_curthread(); 713 sigset_t newset; 714 int ret; 715 716 do { 717 _thr_cancel_enter(curthread); 718 ret = __sys_sigwait(thr_remove_thr_signals(set, &newset), sig); 719 _thr_cancel_leave(curthread, (ret != 0)); 720 } while (ret == EINTR); 721 return (ret); 722 } 723 724 __weak_reference(_setcontext, setcontext); 725 int 726 _setcontext(const ucontext_t *ucp) 727 { 728 ucontext_t uc; 729 730 if (ucp == NULL) { 731 errno = EINVAL; 732 return (-1); 733 } 734 if (!SIGISMEMBER(uc.uc_sigmask, SIGCANCEL)) 735 return __sys_setcontext(ucp); 736 (void) memcpy(&uc, ucp, sizeof(uc)); 737 SIGDELSET(uc.uc_sigmask, SIGCANCEL); 738 return __sys_setcontext(&uc); 739 } 740 741 __weak_reference(_swapcontext, swapcontext); 742 int 743 _swapcontext(ucontext_t *oucp, const ucontext_t *ucp) 744 { 745 ucontext_t uc; 746 747 if (oucp == NULL || ucp == NULL) { 748 errno = EINVAL; 749 return (-1); 750 } 751 if (SIGISMEMBER(ucp->uc_sigmask, SIGCANCEL)) { 752 (void) memcpy(&uc, ucp, sizeof(uc)); 753 SIGDELSET(uc.uc_sigmask, SIGCANCEL); 754 ucp = &uc; 755 } 756 return __sys_swapcontext(oucp, ucp); 757 } 758