thr_sig.c revision 284493
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: stable/10/lib/libthr/thread/thr_sig.c 284493 2015-06-17 04:18:30Z kib $ 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 "libc_private.h" 42#include "thr_private.h" 43 44/* #define DEBUG_SIGNAL */ 45#ifdef DEBUG_SIGNAL 46#define DBG_MSG stdout_debug 47#else 48#define DBG_MSG(x...) 49#endif 50 51struct usigaction { 52 struct sigaction sigact; 53 struct urwlock lock; 54}; 55 56static struct usigaction _thr_sigact[_SIG_MAXSIG]; 57 58static inline struct usigaction * 59__libc_sigaction_slot(int signo) 60{ 61 62 return (&_thr_sigact[signo - 1]); 63} 64 65static void thr_sighandler(int, siginfo_t *, void *); 66static void handle_signal(struct sigaction *, int, siginfo_t *, ucontext_t *); 67static void check_deferred_signal(struct pthread *); 68static void check_suspend(struct pthread *); 69static void check_cancel(struct pthread *curthread, ucontext_t *ucp); 70 71int _sigtimedwait(const sigset_t *set, siginfo_t *info, 72 const struct timespec * timeout); 73int _sigwaitinfo(const sigset_t *set, siginfo_t *info); 74int _sigwait(const sigset_t *set, int *sig); 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, struct sigcontext *scp, 147 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; 156 ucontext_t *ucp; 157 struct sigaction act; 158 struct usigaction *usa; 159 int err; 160 161 err = errno; 162 curthread = _get_curthread(); 163 ucp = _ucp; 164 usa = __libc_sigaction_slot(sig); 165 _thr_rwl_rdlock(&usa->lock); 166 act = usa->sigact; 167 _thr_rwl_unlock(&usa->lock); 168 errno = err; 169 curthread->deferred_run = 0; 170 171 /* 172 * if a thread is in critical region, for example it holds low level locks, 173 * try to defer the signal processing, however if the signal is synchronous 174 * signal, it means a bad thing has happened, this is a programming error, 175 * resuming fault point can not help anything (normally causes deadloop), 176 * so here we let user code handle it immediately. 177 */ 178 if (THR_IN_CRITICAL(curthread) && SIGISMEMBER(_thr_deferset, sig)) { 179 memcpy(&curthread->deferred_sigact, &act, sizeof(struct sigaction)); 180 memcpy(&curthread->deferred_siginfo, info, sizeof(siginfo_t)); 181 curthread->deferred_sigmask = ucp->uc_sigmask; 182 /* mask all signals, we will restore it later. */ 183 ucp->uc_sigmask = _thr_deferset; 184 return; 185 } 186 187 handle_signal(&act, sig, info, ucp); 188} 189 190static void 191handle_signal(struct sigaction *actp, int sig, siginfo_t *info, ucontext_t *ucp) 192{ 193 struct pthread *curthread = _get_curthread(); 194 ucontext_t uc2; 195 __siginfohandler_t *sigfunc; 196 int cancel_point; 197 int cancel_async; 198 int cancel_enable; 199 int in_sigsuspend; 200 int err; 201 202 /* add previous level mask */ 203 SIGSETOR(actp->sa_mask, ucp->uc_sigmask); 204 205 /* add this signal's mask */ 206 if (!(actp->sa_flags & SA_NODEFER)) 207 SIGADDSET(actp->sa_mask, sig); 208 209 in_sigsuspend = curthread->in_sigsuspend; 210 curthread->in_sigsuspend = 0; 211 212 /* 213 * If thread is in deferred cancellation mode, disable cancellation 214 * in signal handler. 215 * If user signal handler calls a cancellation point function, e.g, 216 * it calls write() to write data to file, because write() is a 217 * cancellation point, the thread is immediately cancelled if 218 * cancellation is pending, to avoid this problem while thread is in 219 * deferring mode, cancellation is temporarily disabled. 220 */ 221 cancel_point = curthread->cancel_point; 222 cancel_async = curthread->cancel_async; 223 cancel_enable = curthread->cancel_enable; 224 curthread->cancel_point = 0; 225 if (!cancel_async) 226 curthread->cancel_enable = 0; 227 228 /* restore correct mask before calling user handler */ 229 __sys_sigprocmask(SIG_SETMASK, &actp->sa_mask, NULL); 230 231 sigfunc = actp->sa_sigaction; 232 233 /* 234 * We have already reset cancellation point flags, so if user's code 235 * longjmp()s out of its signal handler, wish its jmpbuf was set 236 * outside of a cancellation point, in most cases, this would be 237 * true. However, there is no way to save cancel_enable in jmpbuf, 238 * so after setjmps() returns once more, the user code may need to 239 * re-set cancel_enable flag by calling pthread_setcancelstate(). 240 */ 241 if ((actp->sa_flags & SA_SIGINFO) != 0) { 242 sigfunc(sig, info, ucp); 243 } else { 244 ((ohandler)sigfunc)(sig, info->si_code, 245 (struct sigcontext *)ucp, info->si_addr, 246 (__sighandler_t *)sigfunc); 247 } 248 err = errno; 249 250 curthread->in_sigsuspend = in_sigsuspend; 251 curthread->cancel_point = cancel_point; 252 curthread->cancel_enable = cancel_enable; 253 254 memcpy(&uc2, ucp, sizeof(uc2)); 255 SIGDELSET(uc2.uc_sigmask, SIGCANCEL); 256 257 /* reschedule cancellation */ 258 check_cancel(curthread, &uc2); 259 errno = err; 260 __sys_sigreturn(&uc2); 261} 262 263void 264_thr_ast(struct pthread *curthread) 265{ 266 267 if (!THR_IN_CRITICAL(curthread)) { 268 check_deferred_signal(curthread); 269 check_suspend(curthread); 270 check_cancel(curthread, NULL); 271 } 272} 273 274/* reschedule cancellation */ 275static void 276check_cancel(struct pthread *curthread, ucontext_t *ucp) 277{ 278 279 if (__predict_true(!curthread->cancel_pending || 280 !curthread->cancel_enable || curthread->no_cancel)) 281 return; 282 283 /* 284 * Otherwise, we are in defer mode, and we are at 285 * cancel point, tell kernel to not block the current 286 * thread on next cancelable system call. 287 * 288 * There are three cases we should call thr_wake() to 289 * turn on TDP_WAKEUP or send SIGCANCEL in kernel: 290 * 1) we are going to call a cancelable system call, 291 * non-zero cancel_point means we are already in 292 * cancelable state, next system call is cancelable. 293 * 2) because _thr_ast() may be called by 294 * THR_CRITICAL_LEAVE() which is used by rtld rwlock 295 * and any libthr internal locks, when rtld rwlock 296 * is used, it is mostly caused by an unresolved PLT. 297 * Those routines may clear the TDP_WAKEUP flag by 298 * invoking some system calls, in those cases, we 299 * also should reenable the flag. 300 * 3) thread is in sigsuspend(), and the syscall insists 301 * on getting a signal before it agrees to return. 302 */ 303 if (curthread->cancel_point) { 304 if (curthread->in_sigsuspend && ucp) { 305 SIGADDSET(ucp->uc_sigmask, SIGCANCEL); 306 curthread->unblock_sigcancel = 1; 307 _thr_send_sig(curthread, SIGCANCEL); 308 } else 309 thr_wake(curthread->tid); 310 } else if (curthread->cancel_async) { 311 /* 312 * asynchronous cancellation mode, act upon 313 * immediately. 314 */ 315 _pthread_exit_mask(PTHREAD_CANCELED, 316 ucp? &ucp->uc_sigmask : NULL); 317 } 318} 319 320static void 321check_deferred_signal(struct pthread *curthread) 322{ 323 ucontext_t *uc; 324 struct sigaction act; 325 siginfo_t info; 326 int uc_len; 327 328 if (__predict_true(curthread->deferred_siginfo.si_signo == 0 || 329 curthread->deferred_run)) 330 return; 331 332 curthread->deferred_run = 1; 333 uc_len = __getcontextx_size(); 334 uc = alloca(uc_len); 335 getcontext(uc); 336 if (curthread->deferred_siginfo.si_signo == 0) { 337 curthread->deferred_run = 0; 338 return; 339 } 340 __fillcontextx2((char *)uc); 341 act = curthread->deferred_sigact; 342 uc->uc_sigmask = curthread->deferred_sigmask; 343 memcpy(&info, &curthread->deferred_siginfo, sizeof(siginfo_t)); 344 /* remove signal */ 345 curthread->deferred_siginfo.si_signo = 0; 346 handle_signal(&act, info.si_signo, &info, uc); 347} 348 349static void 350check_suspend(struct pthread *curthread) 351{ 352 uint32_t cycle; 353 354 if (__predict_true((curthread->flags & 355 (THR_FLAGS_NEED_SUSPEND | THR_FLAGS_SUSPENDED)) 356 != THR_FLAGS_NEED_SUSPEND)) 357 return; 358 if (curthread == _single_thread) 359 return; 360 if (curthread->force_exit) 361 return; 362 363 /* 364 * Blocks SIGCANCEL which other threads must send. 365 */ 366 _thr_signal_block(curthread); 367 368 /* 369 * Increase critical_count, here we don't use THR_LOCK/UNLOCK 370 * because we are leaf code, we don't want to recursively call 371 * ourself. 372 */ 373 curthread->critical_count++; 374 THR_UMUTEX_LOCK(curthread, &(curthread)->lock); 375 while ((curthread->flags & (THR_FLAGS_NEED_SUSPEND | 376 THR_FLAGS_SUSPENDED)) == THR_FLAGS_NEED_SUSPEND) { 377 curthread->cycle++; 378 cycle = curthread->cycle; 379 380 /* Wake the thread suspending us. */ 381 _thr_umtx_wake(&curthread->cycle, INT_MAX, 0); 382 383 /* 384 * if we are from pthread_exit, we don't want to 385 * suspend, just go and die. 386 */ 387 if (curthread->state == PS_DEAD) 388 break; 389 curthread->flags |= THR_FLAGS_SUSPENDED; 390 THR_UMUTEX_UNLOCK(curthread, &(curthread)->lock); 391 _thr_umtx_wait_uint(&curthread->cycle, cycle, NULL, 0); 392 THR_UMUTEX_LOCK(curthread, &(curthread)->lock); 393 curthread->flags &= ~THR_FLAGS_SUSPENDED; 394 } 395 THR_UMUTEX_UNLOCK(curthread, &(curthread)->lock); 396 curthread->critical_count--; 397 398 _thr_signal_unblock(curthread); 399} 400 401void 402_thr_signal_init(int dlopened) 403{ 404 struct sigaction act, nact, oact; 405 struct usigaction *usa; 406 sigset_t oldset; 407 int sig, error; 408 409 if (dlopened) { 410 __sys_sigprocmask(SIG_SETMASK, &_thr_maskset, &oldset); 411 for (sig = 1; sig <= _SIG_MAXSIG; sig++) { 412 if (sig == SIGCANCEL) 413 continue; 414 error = __sys_sigaction(sig, NULL, &oact); 415 if (error == -1 || oact.sa_handler == SIG_DFL || 416 oact.sa_handler == SIG_IGN) 417 continue; 418 usa = __libc_sigaction_slot(sig); 419 usa->sigact = oact; 420 nact = oact; 421 remove_thr_signals(&usa->sigact.sa_mask); 422 nact.sa_flags &= ~SA_NODEFER; 423 nact.sa_flags |= SA_SIGINFO; 424 nact.sa_sigaction = thr_sighandler; 425 nact.sa_mask = _thr_maskset; 426 (void)__sys_sigaction(sig, &nact, NULL); 427 } 428 __sys_sigprocmask(SIG_SETMASK, &oldset, NULL); 429 } 430 431 /* Install SIGCANCEL handler. */ 432 SIGFILLSET(act.sa_mask); 433 act.sa_flags = SA_SIGINFO; 434 act.sa_sigaction = (__siginfohandler_t *)&sigcancel_handler; 435 __sys_sigaction(SIGCANCEL, &act, NULL); 436 437 /* Unblock SIGCANCEL */ 438 SIGEMPTYSET(act.sa_mask); 439 SIGADDSET(act.sa_mask, SIGCANCEL); 440 __sys_sigprocmask(SIG_UNBLOCK, &act.sa_mask, NULL); 441} 442 443void 444_thr_sigact_unload(struct dl_phdr_info *phdr_info) 445{ 446#if 0 447 struct pthread *curthread = _get_curthread(); 448 struct urwlock *rwlp; 449 struct sigaction *actp; 450 struct usigaction *usa; 451 struct sigaction kact; 452 void (*handler)(int); 453 int sig; 454 455 _thr_signal_block(curthread); 456 for (sig = 1; sig <= _SIG_MAXSIG; sig++) { 457 usa = __libc_sigaction_slot(sig); 458 actp = &usa->sigact; 459retry: 460 handler = actp->sa_handler; 461 if (handler != SIG_DFL && handler != SIG_IGN && 462 __elf_phdr_match_addr(phdr_info, handler)) { 463 rwlp = &usa->lock; 464 _thr_rwl_wrlock(rwlp); 465 if (handler != actp->sa_handler) { 466 _thr_rwl_unlock(rwlp); 467 goto retry; 468 } 469 actp->sa_handler = SIG_DFL; 470 actp->sa_flags = SA_SIGINFO; 471 SIGEMPTYSET(actp->sa_mask); 472 if (__sys_sigaction(sig, NULL, &kact) == 0 && 473 kact.sa_handler != SIG_DFL && 474 kact.sa_handler != SIG_IGN) 475 __sys_sigaction(sig, actp, NULL); 476 _thr_rwl_unlock(rwlp); 477 } 478 } 479 _thr_signal_unblock(curthread); 480#endif 481} 482 483void 484_thr_signal_prefork(void) 485{ 486 int i; 487 488 for (i = 1; i <= _SIG_MAXSIG; ++i) 489 _thr_rwl_rdlock(&__libc_sigaction_slot(i)->lock); 490} 491 492void 493_thr_signal_postfork(void) 494{ 495 int i; 496 497 for (i = 1; i <= _SIG_MAXSIG; ++i) 498 _thr_rwl_unlock(&__libc_sigaction_slot(i)->lock); 499} 500 501void 502_thr_signal_postfork_child(void) 503{ 504 int i; 505 506 for (i = 1; i <= _SIG_MAXSIG; ++i) { 507 bzero(&__libc_sigaction_slot(i) -> lock, 508 sizeof(struct urwlock)); 509 } 510} 511 512void 513_thr_signal_deinit(void) 514{ 515} 516 517int 518__thr_sigaction(int sig, const struct sigaction *act, struct sigaction *oact) 519{ 520 struct sigaction newact, oldact, oldact2; 521 sigset_t oldset; 522 struct usigaction *usa; 523 int ret, err; 524 525 if (!_SIG_VALID(sig) || sig == SIGCANCEL) { 526 errno = EINVAL; 527 return (-1); 528 } 529 530 ret = 0; 531 err = 0; 532 usa = __libc_sigaction_slot(sig); 533 534 __sys_sigprocmask(SIG_SETMASK, &_thr_maskset, &oldset); 535 _thr_rwl_wrlock(&usa->lock); 536 537 if (act != NULL) { 538 oldact2 = usa->sigact; 539 newact = *act; 540 541 /* 542 * if a new sig handler is SIG_DFL or SIG_IGN, 543 * don't remove old handler from __libc_sigact[], 544 * so deferred signals still can use the handlers, 545 * multiple threads invoking sigaction itself is 546 * a race condition, so it is not a problem. 547 */ 548 if (newact.sa_handler != SIG_DFL && 549 newact.sa_handler != SIG_IGN) { 550 usa->sigact = newact; 551 remove_thr_signals(&usa->sigact.sa_mask); 552 newact.sa_flags &= ~SA_NODEFER; 553 newact.sa_flags |= SA_SIGINFO; 554 newact.sa_sigaction = thr_sighandler; 555 newact.sa_mask = _thr_maskset; /* mask all signals */ 556 } 557 ret = __sys_sigaction(sig, &newact, &oldact); 558 if (ret == -1) { 559 err = errno; 560 usa->sigact = oldact2; 561 } 562 } else if (oact != NULL) { 563 ret = __sys_sigaction(sig, NULL, &oldact); 564 err = errno; 565 } 566 567 if (oldact.sa_handler != SIG_DFL && oldact.sa_handler != SIG_IGN) { 568 if (act != NULL) 569 oldact = oldact2; 570 else if (oact != NULL) 571 oldact = usa->sigact; 572 } 573 574 _thr_rwl_unlock(&usa->lock); 575 __sys_sigprocmask(SIG_SETMASK, &oldset, NULL); 576 577 if (ret == 0) { 578 if (oact != NULL) 579 *oact = oldact; 580 } else { 581 errno = err; 582 } 583 return (ret); 584} 585 586int 587__thr_sigprocmask(int how, const sigset_t *set, sigset_t *oset) 588{ 589 const sigset_t *p = set; 590 sigset_t newset; 591 592 if (how != SIG_UNBLOCK) { 593 if (set != NULL) { 594 newset = *set; 595 SIGDELSET(newset, SIGCANCEL); 596 p = &newset; 597 } 598 } 599 return (__sys_sigprocmask(how, p, oset)); 600} 601 602__weak_reference(_pthread_sigmask, pthread_sigmask); 603 604int 605_pthread_sigmask(int how, const sigset_t *set, sigset_t *oset) 606{ 607 608 if (__thr_sigprocmask(how, set, oset)) 609 return (errno); 610 return (0); 611} 612 613int 614_sigsuspend(const sigset_t * set) 615{ 616 sigset_t newset; 617 618 return (__sys_sigsuspend(thr_remove_thr_signals(set, &newset))); 619} 620 621int 622__thr_sigsuspend(const sigset_t * set) 623{ 624 struct pthread *curthread; 625 sigset_t newset; 626 int ret, old; 627 628 curthread = _get_curthread(); 629 630 old = curthread->in_sigsuspend; 631 curthread->in_sigsuspend = 1; 632 _thr_cancel_enter(curthread); 633 ret = __sys_sigsuspend(thr_remove_thr_signals(set, &newset)); 634 _thr_cancel_leave(curthread, 1); 635 curthread->in_sigsuspend = old; 636 if (curthread->unblock_sigcancel) { 637 curthread->unblock_sigcancel = 0; 638 SIGEMPTYSET(newset); 639 SIGADDSET(newset, SIGCANCEL); 640 __sys_sigprocmask(SIG_UNBLOCK, &newset, NULL); 641 } 642 643 return (ret); 644} 645 646int 647_sigtimedwait(const sigset_t *set, siginfo_t *info, 648 const struct timespec * timeout) 649{ 650 sigset_t newset; 651 652 return (__sys_sigtimedwait(thr_remove_thr_signals(set, &newset), info, 653 timeout)); 654} 655 656/* 657 * Cancellation behavior: 658 * Thread may be canceled at start, if thread got signal, 659 * it is not canceled. 660 */ 661int 662__thr_sigtimedwait(const sigset_t *set, siginfo_t *info, 663 const struct timespec * timeout) 664{ 665 struct pthread *curthread = _get_curthread(); 666 sigset_t newset; 667 int ret; 668 669 _thr_cancel_enter(curthread); 670 ret = __sys_sigtimedwait(thr_remove_thr_signals(set, &newset), info, 671 timeout); 672 _thr_cancel_leave(curthread, (ret == -1)); 673 return (ret); 674} 675 676int 677_sigwaitinfo(const sigset_t *set, siginfo_t *info) 678{ 679 sigset_t newset; 680 681 return (__sys_sigwaitinfo(thr_remove_thr_signals(set, &newset), info)); 682} 683 684/* 685 * Cancellation behavior: 686 * Thread may be canceled at start, if thread got signal, 687 * it is not canceled. 688 */ 689int 690__thr_sigwaitinfo(const sigset_t *set, siginfo_t *info) 691{ 692 struct pthread *curthread = _get_curthread(); 693 sigset_t newset; 694 int ret; 695 696 _thr_cancel_enter(curthread); 697 ret = __sys_sigwaitinfo(thr_remove_thr_signals(set, &newset), info); 698 _thr_cancel_leave(curthread, ret == -1); 699 return (ret); 700} 701 702int 703_sigwait(const sigset_t *set, int *sig) 704{ 705 sigset_t newset; 706 707 return (__sys_sigwait(thr_remove_thr_signals(set, &newset), sig)); 708} 709 710/* 711 * Cancellation behavior: 712 * Thread may be canceled at start, if thread got signal, 713 * it is not canceled. 714 */ 715int 716__thr_sigwait(const sigset_t *set, int *sig) 717{ 718 struct pthread *curthread = _get_curthread(); 719 sigset_t newset; 720 int ret; 721 722 do { 723 _thr_cancel_enter(curthread); 724 ret = __sys_sigwait(thr_remove_thr_signals(set, &newset), sig); 725 _thr_cancel_leave(curthread, (ret != 0)); 726 } while (ret == EINTR); 727 return (ret); 728} 729 730int 731__thr_setcontext(const ucontext_t *ucp) 732{ 733 ucontext_t uc; 734 735 if (ucp == NULL) { 736 errno = EINVAL; 737 return (-1); 738 } 739 if (!SIGISMEMBER(uc.uc_sigmask, SIGCANCEL)) 740 return __sys_setcontext(ucp); 741 (void) memcpy(&uc, ucp, sizeof(uc)); 742 SIGDELSET(uc.uc_sigmask, SIGCANCEL); 743 return (__sys_setcontext(&uc)); 744} 745 746int 747__thr_swapcontext(ucontext_t *oucp, const ucontext_t *ucp) 748{ 749 ucontext_t uc; 750 751 if (oucp == NULL || ucp == NULL) { 752 errno = EINVAL; 753 return (-1); 754 } 755 if (SIGISMEMBER(ucp->uc_sigmask, SIGCANCEL)) { 756 (void) memcpy(&uc, ucp, sizeof(uc)); 757 SIGDELSET(uc.uc_sigmask, SIGCANCEL); 758 ucp = &uc; 759 } 760 return (__sys_swapcontext(oucp, ucp)); 761} 762