thr_sig.c revision 299521
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 299521 2016-05-12 06:53:22Z kib $ 27 */ 28 29#include "namespace.h" 30#include <sys/param.h> 31#include <sys/types.h> 32#include <sys/signalvar.h> 33#include <sys/syscall.h> 34#include <signal.h> 35#include <errno.h> 36#include <stdlib.h> 37#include <string.h> 38#include <pthread.h> 39#include "un-namespace.h" 40#include "libc_private.h" 41 42#include "libc_private.h" 43#include "thr_private.h" 44 45/* #define DEBUG_SIGNAL */ 46#ifdef DEBUG_SIGNAL 47#define DBG_MSG stdout_debug 48#else 49#define DBG_MSG(x...) 50#endif 51 52struct usigaction { 53 struct sigaction sigact; 54 struct urwlock lock; 55}; 56 57static struct usigaction _thr_sigact[_SIG_MAXSIG]; 58 59static inline struct usigaction * 60__libc_sigaction_slot(int signo) 61{ 62 63 return (&_thr_sigact[signo - 1]); 64} 65 66static void thr_sighandler(int, siginfo_t *, void *); 67static void handle_signal(struct sigaction *, int, siginfo_t *, ucontext_t *); 68static void check_deferred_signal(struct pthread *); 69static void check_suspend(struct pthread *); 70static void check_cancel(struct pthread *curthread, ucontext_t *ucp); 71 72int _sigtimedwait(const sigset_t *set, siginfo_t *info, 73 const struct timespec * timeout); 74int _sigwaitinfo(const sigset_t *set, siginfo_t *info); 75int _sigwait(const sigset_t *set, int *sig); 76int _setcontext(const ucontext_t *); 77int _swapcontext(ucontext_t *, const ucontext_t *); 78 79static const sigset_t _thr_deferset={{ 80 0xffffffff & ~(_SIG_BIT(SIGBUS)|_SIG_BIT(SIGILL)|_SIG_BIT(SIGFPE)| 81 _SIG_BIT(SIGSEGV)|_SIG_BIT(SIGTRAP)|_SIG_BIT(SIGSYS)), 82 0xffffffff, 83 0xffffffff, 84 0xffffffff}}; 85 86static const sigset_t _thr_maskset={{ 87 0xffffffff, 88 0xffffffff, 89 0xffffffff, 90 0xffffffff}}; 91 92void 93_thr_signal_block(struct pthread *curthread) 94{ 95 96 if (curthread->sigblock > 0) { 97 curthread->sigblock++; 98 return; 99 } 100 __sys_sigprocmask(SIG_BLOCK, &_thr_maskset, &curthread->sigmask); 101 curthread->sigblock++; 102} 103 104void 105_thr_signal_unblock(struct pthread *curthread) 106{ 107 if (--curthread->sigblock == 0) 108 __sys_sigprocmask(SIG_SETMASK, &curthread->sigmask, NULL); 109} 110 111int 112_thr_send_sig(struct pthread *thread, int sig) 113{ 114 return thr_kill(thread->tid, sig); 115} 116 117static inline void 118remove_thr_signals(sigset_t *set) 119{ 120 if (SIGISMEMBER(*set, SIGCANCEL)) 121 SIGDELSET(*set, SIGCANCEL); 122} 123 124static const sigset_t * 125thr_remove_thr_signals(const sigset_t *set, sigset_t *newset) 126{ 127 *newset = *set; 128 remove_thr_signals(newset); 129 return (newset); 130} 131 132static void 133sigcancel_handler(int sig __unused, 134 siginfo_t *info __unused, ucontext_t *ucp) 135{ 136 struct pthread *curthread = _get_curthread(); 137 int err; 138 139 if (THR_IN_CRITICAL(curthread)) 140 return; 141 err = errno; 142 check_suspend(curthread); 143 check_cancel(curthread, ucp); 144 errno = err; 145} 146 147typedef void (*ohandler)(int sig, int code, struct sigcontext *scp, 148 char *addr, __sighandler_t *catcher); 149 150/* 151 * The signal handler wrapper is entered with all signal masked. 152 */ 153static void 154thr_sighandler(int sig, siginfo_t *info, void *_ucp) 155{ 156 struct pthread *curthread; 157 ucontext_t *ucp; 158 struct sigaction act; 159 struct usigaction *usa; 160 int err; 161 162 err = errno; 163 curthread = _get_curthread(); 164 ucp = _ucp; 165 usa = __libc_sigaction_slot(sig); 166 _thr_rwl_rdlock(&usa->lock); 167 act = usa->sigact; 168 _thr_rwl_unlock(&usa->lock); 169 errno = err; 170 curthread->deferred_run = 0; 171 172 /* 173 * if a thread is in critical region, for example it holds low level locks, 174 * try to defer the signal processing, however if the signal is synchronous 175 * signal, it means a bad thing has happened, this is a programming error, 176 * resuming fault point can not help anything (normally causes deadloop), 177 * so here we let user code handle it immediately. 178 */ 179 if (THR_IN_CRITICAL(curthread) && SIGISMEMBER(_thr_deferset, sig)) { 180 memcpy(&curthread->deferred_sigact, &act, sizeof(struct sigaction)); 181 memcpy(&curthread->deferred_siginfo, info, sizeof(siginfo_t)); 182 curthread->deferred_sigmask = ucp->uc_sigmask; 183 /* mask all signals, we will restore it later. */ 184 ucp->uc_sigmask = _thr_deferset; 185 return; 186 } 187 188 handle_signal(&act, sig, info, ucp); 189} 190 191static void 192handle_signal(struct sigaction *actp, int sig, siginfo_t *info, ucontext_t *ucp) 193{ 194 struct pthread *curthread = _get_curthread(); 195 ucontext_t uc2; 196 __siginfohandler_t *sigfunc; 197 int cancel_point; 198 int cancel_async; 199 int cancel_enable; 200 int in_sigsuspend; 201 int err; 202 203 /* add previous level mask */ 204 SIGSETOR(actp->sa_mask, ucp->uc_sigmask); 205 206 /* add this signal's mask */ 207 if (!(actp->sa_flags & SA_NODEFER)) 208 SIGADDSET(actp->sa_mask, sig); 209 210 in_sigsuspend = curthread->in_sigsuspend; 211 curthread->in_sigsuspend = 0; 212 213 /* 214 * If thread is in deferred cancellation mode, disable cancellation 215 * in signal handler. 216 * If user signal handler calls a cancellation point function, e.g, 217 * it calls write() to write data to file, because write() is a 218 * cancellation point, the thread is immediately cancelled if 219 * cancellation is pending, to avoid this problem while thread is in 220 * deferring mode, cancellation is temporarily disabled. 221 */ 222 cancel_point = curthread->cancel_point; 223 cancel_async = curthread->cancel_async; 224 cancel_enable = curthread->cancel_enable; 225 curthread->cancel_point = 0; 226 if (!cancel_async) 227 curthread->cancel_enable = 0; 228 229 /* restore correct mask before calling user handler */ 230 __sys_sigprocmask(SIG_SETMASK, &actp->sa_mask, NULL); 231 232 sigfunc = actp->sa_sigaction; 233 234 /* 235 * We have already reset cancellation point flags, so if user's code 236 * longjmp()s out of its signal handler, wish its jmpbuf was set 237 * outside of a cancellation point, in most cases, this would be 238 * true. However, there is no way to save cancel_enable in jmpbuf, 239 * so after setjmps() returns once more, the user code may need to 240 * re-set cancel_enable flag by calling pthread_setcancelstate(). 241 */ 242 if ((actp->sa_flags & SA_SIGINFO) != 0) { 243 sigfunc(sig, info, ucp); 244 } else { 245 ((ohandler)sigfunc)(sig, info->si_code, 246 (struct sigcontext *)ucp, info->si_addr, 247 (__sighandler_t *)sigfunc); 248 } 249 err = errno; 250 251 curthread->in_sigsuspend = in_sigsuspend; 252 curthread->cancel_point = cancel_point; 253 curthread->cancel_enable = cancel_enable; 254 255 memcpy(&uc2, ucp, sizeof(uc2)); 256 SIGDELSET(uc2.uc_sigmask, SIGCANCEL); 257 258 /* reschedule cancellation */ 259 check_cancel(curthread, &uc2); 260 errno = err; 261 syscall(SYS_sigreturn, &uc2); 262} 263 264void 265_thr_ast(struct pthread *curthread) 266{ 267 268 if (!THR_IN_CRITICAL(curthread)) { 269 check_deferred_signal(curthread); 270 check_suspend(curthread); 271 check_cancel(curthread, NULL); 272 } 273} 274 275/* reschedule cancellation */ 276static void 277check_cancel(struct pthread *curthread, ucontext_t *ucp) 278{ 279 280 if (__predict_true(!curthread->cancel_pending || 281 !curthread->cancel_enable || curthread->no_cancel)) 282 return; 283 284 /* 285 * Otherwise, we are in defer mode, and we are at 286 * cancel point, tell kernel to not block the current 287 * thread on next cancelable system call. 288 * 289 * There are three cases we should call thr_wake() to 290 * turn on TDP_WAKEUP or send SIGCANCEL in kernel: 291 * 1) we are going to call a cancelable system call, 292 * non-zero cancel_point means we are already in 293 * cancelable state, next system call is cancelable. 294 * 2) because _thr_ast() may be called by 295 * THR_CRITICAL_LEAVE() which is used by rtld rwlock 296 * and any libthr internal locks, when rtld rwlock 297 * is used, it is mostly caused by an unresolved PLT. 298 * Those routines may clear the TDP_WAKEUP flag by 299 * invoking some system calls, in those cases, we 300 * also should reenable the flag. 301 * 3) thread is in sigsuspend(), and the syscall insists 302 * on getting a signal before it agrees to return. 303 */ 304 if (curthread->cancel_point) { 305 if (curthread->in_sigsuspend && ucp) { 306 SIGADDSET(ucp->uc_sigmask, SIGCANCEL); 307 curthread->unblock_sigcancel = 1; 308 _thr_send_sig(curthread, SIGCANCEL); 309 } else 310 thr_wake(curthread->tid); 311 } else if (curthread->cancel_async) { 312 /* 313 * asynchronous cancellation mode, act upon 314 * immediately. 315 */ 316 _pthread_exit_mask(PTHREAD_CANCELED, 317 ucp? &ucp->uc_sigmask : NULL); 318 } 319} 320 321static void 322check_deferred_signal(struct pthread *curthread) 323{ 324 ucontext_t *uc; 325 struct sigaction act; 326 siginfo_t info; 327 int uc_len; 328 329 if (__predict_true(curthread->deferred_siginfo.si_signo == 0 || 330 curthread->deferred_run)) 331 return; 332 333 curthread->deferred_run = 1; 334 uc_len = __getcontextx_size(); 335 uc = alloca(uc_len); 336 getcontext(uc); 337 if (curthread->deferred_siginfo.si_signo == 0) { 338 curthread->deferred_run = 0; 339 return; 340 } 341 __fillcontextx2((char *)uc); 342 act = curthread->deferred_sigact; 343 uc->uc_sigmask = curthread->deferred_sigmask; 344 memcpy(&info, &curthread->deferred_siginfo, sizeof(siginfo_t)); 345 /* remove signal */ 346 curthread->deferred_siginfo.si_signo = 0; 347 handle_signal(&act, info.si_signo, &info, uc); 348} 349 350static void 351check_suspend(struct pthread *curthread) 352{ 353 uint32_t cycle; 354 355 if (__predict_true((curthread->flags & 356 (THR_FLAGS_NEED_SUSPEND | THR_FLAGS_SUSPENDED)) 357 != THR_FLAGS_NEED_SUSPEND)) 358 return; 359 if (curthread == _single_thread) 360 return; 361 if (curthread->force_exit) 362 return; 363 364 /* 365 * Blocks SIGCANCEL which other threads must send. 366 */ 367 _thr_signal_block(curthread); 368 369 /* 370 * Increase critical_count, here we don't use THR_LOCK/UNLOCK 371 * because we are leaf code, we don't want to recursively call 372 * ourself. 373 */ 374 curthread->critical_count++; 375 THR_UMUTEX_LOCK(curthread, &(curthread)->lock); 376 while ((curthread->flags & THR_FLAGS_NEED_SUSPEND) != 0) { 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 } 394 THR_UMUTEX_UNLOCK(curthread, &(curthread)->lock); 395 curthread->critical_count--; 396 397 _thr_signal_unblock(curthread); 398} 399 400void 401_thr_signal_init(int dlopened) 402{ 403 struct sigaction act, nact, oact; 404 struct usigaction *usa; 405 sigset_t oldset; 406 int sig, error; 407 408 if (dlopened) { 409 __sys_sigprocmask(SIG_SETMASK, &_thr_maskset, &oldset); 410 for (sig = 1; sig <= _SIG_MAXSIG; sig++) { 411 if (sig == SIGCANCEL) 412 continue; 413 error = __sys_sigaction(sig, NULL, &oact); 414 if (error == -1 || oact.sa_handler == SIG_DFL || 415 oact.sa_handler == SIG_IGN) 416 continue; 417 usa = __libc_sigaction_slot(sig); 418 usa->sigact = oact; 419 nact = oact; 420 remove_thr_signals(&usa->sigact.sa_mask); 421 nact.sa_flags &= ~SA_NODEFER; 422 nact.sa_flags |= SA_SIGINFO; 423 nact.sa_sigaction = thr_sighandler; 424 nact.sa_mask = _thr_maskset; 425 (void)__sys_sigaction(sig, &nact, NULL); 426 } 427 __sys_sigprocmask(SIG_SETMASK, &oldset, NULL); 428 } 429 430 /* Install SIGCANCEL handler. */ 431 SIGFILLSET(act.sa_mask); 432 act.sa_flags = SA_SIGINFO; 433 act.sa_sigaction = (__siginfohandler_t *)&sigcancel_handler; 434 __sys_sigaction(SIGCANCEL, &act, NULL); 435 436 /* Unblock SIGCANCEL */ 437 SIGEMPTYSET(act.sa_mask); 438 SIGADDSET(act.sa_mask, SIGCANCEL); 439 __sys_sigprocmask(SIG_UNBLOCK, &act.sa_mask, NULL); 440} 441 442void 443_thr_sigact_unload(struct dl_phdr_info *phdr_info) 444{ 445#if 0 446 struct pthread *curthread = _get_curthread(); 447 struct urwlock *rwlp; 448 struct sigaction *actp; 449 struct usigaction *usa; 450 struct sigaction kact; 451 void (*handler)(int); 452 int sig; 453 454 _thr_signal_block(curthread); 455 for (sig = 1; sig <= _SIG_MAXSIG; sig++) { 456 usa = __libc_sigaction_slot(sig); 457 actp = &usa->sigact; 458retry: 459 handler = actp->sa_handler; 460 if (handler != SIG_DFL && handler != SIG_IGN && 461 __elf_phdr_match_addr(phdr_info, handler)) { 462 rwlp = &usa->lock; 463 _thr_rwl_wrlock(rwlp); 464 if (handler != actp->sa_handler) { 465 _thr_rwl_unlock(rwlp); 466 goto retry; 467 } 468 actp->sa_handler = SIG_DFL; 469 actp->sa_flags = SA_SIGINFO; 470 SIGEMPTYSET(actp->sa_mask); 471 if (__sys_sigaction(sig, NULL, &kact) == 0 && 472 kact.sa_handler != SIG_DFL && 473 kact.sa_handler != SIG_IGN) 474 __sys_sigaction(sig, actp, NULL); 475 _thr_rwl_unlock(rwlp); 476 } 477 } 478 _thr_signal_unblock(curthread); 479#endif 480} 481 482void 483_thr_signal_prefork(void) 484{ 485 int i; 486 487 for (i = 1; i <= _SIG_MAXSIG; ++i) 488 _thr_rwl_rdlock(&__libc_sigaction_slot(i)->lock); 489} 490 491void 492_thr_signal_postfork(void) 493{ 494 int i; 495 496 for (i = 1; i <= _SIG_MAXSIG; ++i) 497 _thr_rwl_unlock(&__libc_sigaction_slot(i)->lock); 498} 499 500void 501_thr_signal_postfork_child(void) 502{ 503 int i; 504 505 for (i = 1; i <= _SIG_MAXSIG; ++i) { 506 bzero(&__libc_sigaction_slot(i) -> lock, 507 sizeof(struct urwlock)); 508 } 509} 510 511void 512_thr_signal_deinit(void) 513{ 514} 515 516int 517__thr_sigaction(int sig, const struct sigaction *act, struct sigaction *oact) 518{ 519 struct sigaction newact, oldact, oldact2; 520 sigset_t oldset; 521 struct usigaction *usa; 522 int ret, err; 523 524 if (!_SIG_VALID(sig) || sig == SIGCANCEL) { 525 errno = EINVAL; 526 return (-1); 527 } 528 529 ret = 0; 530 err = 0; 531 usa = __libc_sigaction_slot(sig); 532 533 __sys_sigprocmask(SIG_SETMASK, &_thr_maskset, &oldset); 534 _thr_rwl_wrlock(&usa->lock); 535 536 if (act != NULL) { 537 oldact2 = usa->sigact; 538 newact = *act; 539 540 /* 541 * if a new sig handler is SIG_DFL or SIG_IGN, 542 * don't remove old handler from __libc_sigact[], 543 * so deferred signals still can use the handlers, 544 * multiple threads invoking sigaction itself is 545 * a race condition, so it is not a problem. 546 */ 547 if (newact.sa_handler != SIG_DFL && 548 newact.sa_handler != SIG_IGN) { 549 usa->sigact = newact; 550 remove_thr_signals(&usa->sigact.sa_mask); 551 newact.sa_flags &= ~SA_NODEFER; 552 newact.sa_flags |= SA_SIGINFO; 553 newact.sa_sigaction = thr_sighandler; 554 newact.sa_mask = _thr_maskset; /* mask all signals */ 555 } 556 ret = __sys_sigaction(sig, &newact, &oldact); 557 if (ret == -1) { 558 err = errno; 559 usa->sigact = oldact2; 560 } 561 } else if (oact != NULL) { 562 ret = __sys_sigaction(sig, NULL, &oldact); 563 err = errno; 564 } 565 566 if (oldact.sa_handler != SIG_DFL && oldact.sa_handler != SIG_IGN) { 567 if (act != NULL) 568 oldact = oldact2; 569 else if (oact != NULL) 570 oldact = usa->sigact; 571 } 572 573 _thr_rwl_unlock(&usa->lock); 574 __sys_sigprocmask(SIG_SETMASK, &oldset, NULL); 575 576 if (ret == 0) { 577 if (oact != NULL) 578 *oact = oldact; 579 } else { 580 errno = err; 581 } 582 return (ret); 583} 584 585int 586__thr_sigprocmask(int how, const sigset_t *set, sigset_t *oset) 587{ 588 const sigset_t *p = set; 589 sigset_t newset; 590 591 if (how != SIG_UNBLOCK) { 592 if (set != NULL) { 593 newset = *set; 594 SIGDELSET(newset, SIGCANCEL); 595 p = &newset; 596 } 597 } 598 return (__sys_sigprocmask(how, p, oset)); 599} 600 601__weak_reference(_pthread_sigmask, pthread_sigmask); 602 603int 604_pthread_sigmask(int how, const sigset_t *set, sigset_t *oset) 605{ 606 607 if (__thr_sigprocmask(how, set, oset)) 608 return (errno); 609 return (0); 610} 611 612int 613_sigsuspend(const sigset_t * set) 614{ 615 sigset_t newset; 616 617 return (__sys_sigsuspend(thr_remove_thr_signals(set, &newset))); 618} 619 620int 621__thr_sigsuspend(const sigset_t * set) 622{ 623 struct pthread *curthread; 624 sigset_t newset; 625 int ret, old; 626 627 curthread = _get_curthread(); 628 629 old = curthread->in_sigsuspend; 630 curthread->in_sigsuspend = 1; 631 _thr_cancel_enter(curthread); 632 ret = __sys_sigsuspend(thr_remove_thr_signals(set, &newset)); 633 _thr_cancel_leave(curthread, 1); 634 curthread->in_sigsuspend = old; 635 if (curthread->unblock_sigcancel) { 636 curthread->unblock_sigcancel = 0; 637 SIGEMPTYSET(newset); 638 SIGADDSET(newset, SIGCANCEL); 639 __sys_sigprocmask(SIG_UNBLOCK, &newset, NULL); 640 } 641 642 return (ret); 643} 644 645int 646_sigtimedwait(const sigset_t *set, siginfo_t *info, 647 const struct timespec * timeout) 648{ 649 sigset_t newset; 650 651 return (__sys_sigtimedwait(thr_remove_thr_signals(set, &newset), info, 652 timeout)); 653} 654 655/* 656 * Cancellation behavior: 657 * Thread may be canceled at start, if thread got signal, 658 * it is not canceled. 659 */ 660int 661__thr_sigtimedwait(const sigset_t *set, siginfo_t *info, 662 const struct timespec * timeout) 663{ 664 struct pthread *curthread = _get_curthread(); 665 sigset_t newset; 666 int ret; 667 668 _thr_cancel_enter(curthread); 669 ret = __sys_sigtimedwait(thr_remove_thr_signals(set, &newset), info, 670 timeout); 671 _thr_cancel_leave(curthread, (ret == -1)); 672 return (ret); 673} 674 675int 676_sigwaitinfo(const sigset_t *set, siginfo_t *info) 677{ 678 sigset_t newset; 679 680 return (__sys_sigwaitinfo(thr_remove_thr_signals(set, &newset), info)); 681} 682 683/* 684 * Cancellation behavior: 685 * Thread may be canceled at start, if thread got signal, 686 * it is not canceled. 687 */ 688int 689__thr_sigwaitinfo(const sigset_t *set, siginfo_t *info) 690{ 691 struct pthread *curthread = _get_curthread(); 692 sigset_t newset; 693 int ret; 694 695 _thr_cancel_enter(curthread); 696 ret = __sys_sigwaitinfo(thr_remove_thr_signals(set, &newset), info); 697 _thr_cancel_leave(curthread, ret == -1); 698 return (ret); 699} 700 701int 702_sigwait(const sigset_t *set, int *sig) 703{ 704 sigset_t newset; 705 706 return (__sys_sigwait(thr_remove_thr_signals(set, &newset), sig)); 707} 708 709/* 710 * Cancellation behavior: 711 * Thread may be canceled at start, if thread got signal, 712 * it is not canceled. 713 */ 714int 715__thr_sigwait(const sigset_t *set, int *sig) 716{ 717 struct pthread *curthread = _get_curthread(); 718 sigset_t newset; 719 int ret; 720 721 do { 722 _thr_cancel_enter(curthread); 723 ret = __sys_sigwait(thr_remove_thr_signals(set, &newset), sig); 724 _thr_cancel_leave(curthread, (ret != 0)); 725 } while (ret == EINTR); 726 return (ret); 727} 728 729int 730__thr_setcontext(const ucontext_t *ucp) 731{ 732 ucontext_t uc; 733 734 if (ucp == NULL) { 735 errno = EINVAL; 736 return (-1); 737 } 738 if (!SIGISMEMBER(uc.uc_sigmask, SIGCANCEL)) 739 return __sys_setcontext(ucp); 740 (void) memcpy(&uc, ucp, sizeof(uc)); 741 SIGDELSET(uc.uc_sigmask, SIGCANCEL); 742 return (__sys_setcontext(&uc)); 743} 744 745int 746__thr_swapcontext(ucontext_t *oucp, const ucontext_t *ucp) 747{ 748 ucontext_t uc; 749 750 if (oucp == NULL || ucp == NULL) { 751 errno = EINVAL; 752 return (-1); 753 } 754 if (SIGISMEMBER(ucp->uc_sigmask, SIGCANCEL)) { 755 (void) memcpy(&uc, ucp, sizeof(uc)); 756 SIGDELSET(uc.uc_sigmask, SIGCANCEL); 757 ucp = &uc; 758 } 759 return (__sys_swapcontext(oucp, ucp)); 760} 761