1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 22 /* 23 * Copyright 2006 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27 #pragma ident "%Z%%M% %I% %E% SMI" 28 29 #include "lint.h" 30 #include "thr_uberdata.h" 31 #include "asyncio.h" 32 #include <signal.h> 33 #include <siginfo.h> 34 #include <ucontext.h> 35 #include <sys/systm.h> 36 37 const sigset_t maskset = {MASKSET0, MASKSET1, 0, 0}; /* maskable signals */ 38 39 /* 40 * Return true if the valid signal bits in both sets are the same. 41 */ 42 int 43 sigequalset(const sigset_t *s1, const sigset_t *s2) 44 { 45 /* 46 * We only test valid signal bits, not rubbish following MAXSIG 47 * (for speed). Algorithm: 48 * if (s1 & fillset) == (s2 & fillset) then (s1 ^ s2) & fillset == 0 49 */ 50 return (!((s1->__sigbits[0] ^ s2->__sigbits[0]) | 51 ((s1->__sigbits[1] ^ s2->__sigbits[1]) & FILLSET1))); 52 } 53 54 /* 55 * Common code for calling the user-specified signal handler. 56 */ 57 void 58 call_user_handler(int sig, siginfo_t *sip, ucontext_t *ucp) 59 { 60 ulwp_t *self = curthread; 61 uberdata_t *udp = self->ul_uberdata; 62 struct sigaction uact; 63 volatile struct sigaction *sap; 64 65 /* 66 * If we are taking a signal while parked or about to be parked 67 * on __lwp_park() then remove ourself from the sleep queue so 68 * that we can grab locks. The code in mutex_lock_queue() and 69 * cond_wait_common() will detect this and deal with it when 70 * __lwp_park() returns. 71 */ 72 unsleep_self(); 73 set_parking_flag(self, 0); 74 75 if (__td_event_report(self, TD_CATCHSIG, udp)) { 76 self->ul_td_evbuf.eventnum = TD_CATCHSIG; 77 self->ul_td_evbuf.eventdata = (void *)(intptr_t)sig; 78 tdb_event(TD_CATCHSIG, udp); 79 } 80 81 /* 82 * Get a self-consistent set of flags, handler, and mask 83 * while holding the sig's sig_lock for the least possible time. 84 * We must acquire the sig's sig_lock because some thread running 85 * in sigaction() might be establishing a new signal handler. 86 * 87 * Locking exceptions: 88 * No locking for a child of vfork(). 89 * If the signal is SIGPROF with an si_code of PROF_SIG, 90 * then we assume that this signal was generated by 91 * setitimer(ITIMER_REALPROF) set up by the dbx collector. 92 * If the signal is SIGEMT with an si_code of EMT_CPCOVF, 93 * then we assume that the signal was generated by 94 * a hardware performance counter overflow. 95 * In these cases, assume that we need no locking. It is the 96 * monitoring program's responsibility to ensure correctness. 97 */ 98 sap = &udp->siguaction[sig].sig_uaction; 99 if (self->ul_vfork || 100 (sip != NULL && 101 ((sig == SIGPROF && sip->si_code == PROF_SIG) || 102 (sig == SIGEMT && sip->si_code == EMT_CPCOVF)))) { 103 /* we wish this assignment could be atomic */ 104 (void) _private_memcpy(&uact, (void *)sap, sizeof (uact)); 105 } else { 106 mutex_t *mp = &udp->siguaction[sig].sig_lock; 107 lmutex_lock(mp); 108 (void) _private_memcpy(&uact, (void *)sap, sizeof (uact)); 109 if (sig == SIGCANCEL && (sap->sa_flags & SA_RESETHAND)) 110 sap->sa_sigaction = SIG_DFL; 111 lmutex_unlock(mp); 112 } 113 114 /* 115 * Set the proper signal mask and call the user's signal handler. 116 * (We overrode the user-requested signal mask with maskset 117 * so we currently have all blockable signals blocked.) 118 * 119 * We would like to ASSERT() that the signal is not a member of the 120 * signal mask at the previous level (ucp->uc_sigmask) or the specified 121 * signal mask for sigsuspend() or pollsys() (self->ul_tmpmask) but 122 * /proc can override this via PCSSIG, so we don't bother. 123 * 124 * We would also like to ASSERT() that the signal mask at the previous 125 * level equals self->ul_sigmask (maskset for sigsuspend() / pollsys()), 126 * but /proc can change the thread's signal mask via PCSHOLD, so we 127 * don't bother with that either. 128 */ 129 ASSERT(ucp->uc_flags & UC_SIGMASK); 130 if (self->ul_sigsuspend) { 131 ucp->uc_sigmask = self->ul_sigmask; 132 self->ul_sigsuspend = 0; 133 /* the sigsuspend() or pollsys() signal mask */ 134 sigorset(&uact.sa_mask, &self->ul_tmpmask); 135 } else { 136 /* the signal mask at the previous level */ 137 sigorset(&uact.sa_mask, &ucp->uc_sigmask); 138 } 139 if (!(uact.sa_flags & SA_NODEFER)) /* add current signal */ 140 (void) _private_sigaddset(&uact.sa_mask, sig); 141 self->ul_sigmask = uact.sa_mask; 142 self->ul_siglink = ucp; 143 (void) __lwp_sigmask(SIG_SETMASK, &uact.sa_mask, NULL); 144 145 /* 146 * If this thread has been sent SIGCANCEL from the kernel 147 * or from pthread_cancel(), it is being asked to exit. 148 * The kernel may send SIGCANCEL without a siginfo struct. 149 * If the SIGCANCEL is process-directed (from kill() or 150 * sigqueue()), treat it as an ordinary signal. 151 */ 152 if (sig == SIGCANCEL) { 153 if (sip == NULL || SI_FROMKERNEL(sip) || 154 sip->si_code == SI_LWP) { 155 do_sigcancel(); 156 goto out; 157 } 158 /* SIGCANCEL is ignored by default */ 159 if (uact.sa_sigaction == SIG_DFL || 160 uact.sa_sigaction == SIG_IGN) 161 goto out; 162 } 163 164 /* 165 * If this thread has been sent SIGAIOCANCEL (SIGLWP) and 166 * we are an aio worker thread, cancel the aio request. 167 */ 168 if (sig == SIGAIOCANCEL) { 169 aio_worker_t *aiowp = _pthread_getspecific(_aio_key); 170 171 if (sip != NULL && sip->si_code == SI_LWP && aiowp != NULL) 172 _siglongjmp(aiowp->work_jmp_buf, 1); 173 /* SIGLWP is ignored by default */ 174 if (uact.sa_sigaction == SIG_DFL || 175 uact.sa_sigaction == SIG_IGN) 176 goto out; 177 } 178 179 if (!(uact.sa_flags & SA_SIGINFO)) 180 sip = NULL; 181 __sighndlr(sig, sip, ucp, uact.sa_sigaction); 182 183 #if defined(sparc) || defined(__sparc) 184 /* 185 * If this is a floating point exception and the queue 186 * is non-empty, pop the top entry from the queue. This 187 * is to maintain expected behavior. 188 */ 189 if (sig == SIGFPE && ucp->uc_mcontext.fpregs.fpu_qcnt) { 190 fpregset_t *fp = &ucp->uc_mcontext.fpregs; 191 192 if (--fp->fpu_qcnt > 0) { 193 unsigned char i; 194 struct fq *fqp; 195 196 fqp = fp->fpu_q; 197 for (i = 0; i < fp->fpu_qcnt; i++) 198 fqp[i] = fqp[i+1]; 199 } 200 } 201 #endif /* sparc */ 202 203 out: 204 (void) _private_setcontext(ucp); 205 thr_panic("call_user_handler(): _setcontext() returned"); 206 } 207 208 /* 209 * take_deferred_signal() is called when ul_critical and ul_sigdefer become 210 * zero and a deferred signal has been recorded on the current thread. 211 * We are out of the critical region and are ready to take a signal. 212 * The kernel has all signals blocked on this lwp, but our value of 213 * ul_sigmask is the correct signal mask for the previous context. 214 */ 215 void 216 take_deferred_signal(int sig) 217 { 218 ulwp_t *self = curthread; 219 siginfo_t siginfo; 220 siginfo_t *sip; 221 ucontext_t uc; 222 volatile int returning; 223 224 ASSERT(self->ul_critical == 0); 225 ASSERT(self->ul_sigdefer == 0); 226 ASSERT(self->ul_cursig == 0); 227 228 returning = 0; 229 uc.uc_flags = UC_ALL; 230 /* 231 * We call _private_getcontext (a libc-private synonym for 232 * _getcontext) rather than _getcontext because we need to 233 * avoid the dynamic linker and link auditing problems here. 234 */ 235 (void) _private_getcontext(&uc); 236 /* 237 * If the application signal handler calls setcontext() on 238 * the ucontext we give it, it returns here, then we return. 239 */ 240 if (returning) 241 return; 242 returning = 1; 243 ASSERT(sigequalset(&uc.uc_sigmask, &maskset)); 244 if (self->ul_siginfo.si_signo == 0) 245 sip = NULL; 246 else { 247 (void) _private_memcpy(&siginfo, 248 &self->ul_siginfo, sizeof (siginfo)); 249 sip = &siginfo; 250 } 251 uc.uc_sigmask = self->ul_sigmask; 252 call_user_handler(sig, sip, &uc); 253 } 254 255 void 256 sigacthandler(int sig, siginfo_t *sip, void *uvp) 257 { 258 ucontext_t *ucp = uvp; 259 ulwp_t *self = curthread; 260 261 /* 262 * Do this in case we took a signal while in a cancelable system call. 263 * It does no harm if we were not in such a system call. 264 */ 265 self->ul_sp = 0; 266 if (sig != SIGCANCEL) 267 self->ul_cancel_async = self->ul_save_async; 268 269 /* 270 * If we are not in a critical region and are 271 * not deferring signals, take the signal now. 272 */ 273 if ((self->ul_critical + self->ul_sigdefer) == 0) { 274 call_user_handler(sig, sip, ucp); 275 return; /* call_user_handler() cannot return */ 276 } 277 278 /* 279 * We are in a critical region or we are deferring signals. When 280 * we emerge from the region we will call take_deferred_signal(). 281 */ 282 ASSERT(self->ul_cursig == 0); 283 self->ul_cursig = (char)sig; 284 if (sip != NULL) 285 (void) _private_memcpy(&self->ul_siginfo, 286 sip, sizeof (siginfo_t)); 287 else 288 self->ul_siginfo.si_signo = 0; 289 290 /* 291 * Make sure that if we return to a call to __lwp_park() 292 * or ___lwp_cond_wait() that it returns right away 293 * (giving us a spurious wakeup but not a deadlock). 294 */ 295 set_parking_flag(self, 0); 296 297 /* 298 * Return to the previous context with all signals blocked. 299 * We will restore the signal mask in take_deferred_signal(). 300 * Note that we are calling the system call trap here, not 301 * the _setcontext() wrapper. We don't want to change the 302 * thread's ul_sigmask by this operation. 303 */ 304 ucp->uc_sigmask = maskset; 305 (void) __setcontext_syscall(ucp); 306 thr_panic("sigacthandler(): __setcontext() returned"); 307 } 308 309 #pragma weak sigaction = _libc_sigaction 310 #pragma weak _sigaction = _libc_sigaction 311 int 312 _libc_sigaction(int sig, const struct sigaction *nact, struct sigaction *oact) 313 { 314 ulwp_t *self = curthread; 315 uberdata_t *udp = self->ul_uberdata; 316 struct sigaction oaction; 317 struct sigaction tact; 318 struct sigaction *tactp = NULL; 319 int rv; 320 321 if (sig <= 0 || sig >= NSIG) { 322 errno = EINVAL; 323 return (-1); 324 } 325 326 if (!self->ul_vfork) 327 lmutex_lock(&udp->siguaction[sig].sig_lock); 328 329 oaction = udp->siguaction[sig].sig_uaction; 330 331 if (nact != NULL) { 332 tact = *nact; /* make a copy so we can modify it */ 333 tactp = &tact; 334 delete_reserved_signals(&tact.sa_mask); 335 336 #if !defined(_LP64) 337 tact.sa_resv[0] = tact.sa_resv[1] = 0; /* cleanliness */ 338 #endif 339 /* 340 * To be compatible with the behavior of SunOS 4.x: 341 * If the new signal handler is SIG_IGN or SIG_DFL, do 342 * not change the signal's entry in the siguaction array. 343 * This allows a child of vfork(2) to set signal handlers 344 * to SIG_IGN or SIG_DFL without affecting the parent. 345 * 346 * This also covers a race condition with some thread 347 * setting the signal action to SIG_DFL or SIG_IGN 348 * when the thread has also received and deferred 349 * that signal. When the thread takes the deferred 350 * signal, even though it has set the action to SIG_DFL 351 * or SIG_IGN, it will execute the old signal handler 352 * anyway. This is an inherent signaling race condition 353 * and is not a bug. 354 * 355 * A child of vfork() is not allowed to change signal 356 * handlers to anything other than SIG_DFL or SIG_IGN. 357 */ 358 if (self->ul_vfork) { 359 if (tact.sa_sigaction != SIG_IGN) 360 tact.sa_sigaction = SIG_DFL; 361 } else if (sig == SIGCANCEL || sig == SIGAIOCANCEL) { 362 /* 363 * Always catch these signals. 364 * We need SIGCANCEL for pthread_cancel() to work. 365 * We need SIGAIOCANCEL for aio_cancel() to work. 366 */ 367 udp->siguaction[sig].sig_uaction = tact; 368 if (tact.sa_sigaction == SIG_DFL || 369 tact.sa_sigaction == SIG_IGN) 370 tact.sa_flags = SA_SIGINFO; 371 else { 372 tact.sa_flags |= SA_SIGINFO; 373 tact.sa_flags &= ~(SA_NODEFER | SA_RESETHAND); 374 } 375 tact.sa_sigaction = udp->sigacthandler; 376 tact.sa_mask = maskset; 377 } else if (tact.sa_sigaction != SIG_DFL && 378 tact.sa_sigaction != SIG_IGN) { 379 udp->siguaction[sig].sig_uaction = tact; 380 tact.sa_flags &= ~SA_NODEFER; 381 tact.sa_sigaction = udp->sigacthandler; 382 tact.sa_mask = maskset; 383 } 384 } 385 386 if ((rv = __sigaction(sig, tactp, oact)) != 0) 387 udp->siguaction[sig].sig_uaction = oaction; 388 else if (oact != NULL && 389 oact->sa_sigaction != SIG_DFL && 390 oact->sa_sigaction != SIG_IGN) 391 *oact = oaction; 392 393 /* 394 * We detect setting the disposition of SIGIO just to set the 395 * _sigio_enabled flag for the asynchronous i/o (aio) code. 396 */ 397 if (sig == SIGIO && rv == 0 && tactp != NULL) { 398 _sigio_enabled = 399 (tactp->sa_handler != SIG_DFL && 400 tactp->sa_handler != SIG_IGN); 401 } 402 403 if (!self->ul_vfork) 404 lmutex_unlock(&udp->siguaction[sig].sig_lock); 405 return (rv); 406 } 407 408 void 409 setsigacthandler(void (*nsigacthandler)(int, siginfo_t *, void *), 410 void (**osigacthandler)(int, siginfo_t *, void *)) 411 { 412 ulwp_t *self = curthread; 413 uberdata_t *udp = self->ul_uberdata; 414 415 if (osigacthandler != NULL) 416 *osigacthandler = udp->sigacthandler; 417 418 udp->sigacthandler = nsigacthandler; 419 } 420 421 /* 422 * Calling set_parking_flag(curthread, 1) informs the kernel that we are 423 * calling __lwp_park or ___lwp_cond_wait(). If we take a signal in 424 * the unprotected (from signals) interval before reaching the kernel, 425 * sigacthandler() will call set_parking_flag(curthread, 0) to inform 426 * the kernel to return immediately from these system calls, giving us 427 * a spurious wakeup but not a deadlock. 428 */ 429 void 430 set_parking_flag(ulwp_t *self, int park) 431 { 432 volatile sc_shared_t *scp; 433 434 enter_critical(self); 435 if ((scp = self->ul_schedctl) != NULL || 436 (scp = setup_schedctl()) != NULL) 437 scp->sc_park = park; 438 else if (park == 0) /* schedctl failed, do it the long way */ 439 __lwp_unpark(self->ul_lwpid); 440 exit_critical(self); 441 } 442 443 /* 444 * Tell the kernel to block all signals. 445 * Use the schedctl interface, or failing that, use __lwp_sigmask(). 446 * This action can be rescinded only by making a system call that 447 * sets the signal mask: 448 * __lwp_sigmask(), __sigprocmask(), __setcontext(), 449 * __sigsuspend() or __pollsys(). 450 * In particular, this action cannot be reversed by assigning 451 * scp->sc_sigblock = 0. That would be a way to lose signals. 452 * See the definition of restore_signals(self). 453 */ 454 void 455 block_all_signals(ulwp_t *self) 456 { 457 volatile sc_shared_t *scp; 458 459 enter_critical(self); 460 if ((scp = self->ul_schedctl) != NULL || 461 (scp = setup_schedctl()) != NULL) 462 scp->sc_sigblock = 1; 463 else 464 (void) __lwp_sigmask(SIG_SETMASK, &maskset, NULL); 465 exit_critical(self); 466 } 467 468 /* 469 * _private_setcontext has code that forcibly restores the curthread 470 * pointer in a context passed to the setcontext(2) syscall. 471 * 472 * Certain processes may need to disable this feature, so these routines 473 * provide the mechanism to do so. 474 * 475 * (As an example, branded 32-bit x86 processes may use %gs for their own 476 * purposes, so they need to be able to specify a %gs value to be restored 477 * on return from a signal handler via the passed ucontext_t.) 478 */ 479 static int setcontext_enforcement = 1; 480 481 void 482 set_setcontext_enforcement(int on) 483 { 484 setcontext_enforcement = on; 485 } 486 487 #pragma weak setcontext = _private_setcontext 488 #pragma weak _setcontext = _private_setcontext 489 int 490 _private_setcontext(const ucontext_t *ucp) 491 { 492 ulwp_t *self = curthread; 493 int ret; 494 ucontext_t uc; 495 496 /* 497 * Returning from the main context (uc_link == NULL) causes 498 * the thread to exit. See setcontext(2) and makecontext(3C). 499 */ 500 if (ucp == NULL) 501 _thr_exit(NULL); 502 (void) _private_memcpy(&uc, ucp, sizeof (uc)); 503 504 /* 505 * Restore previous signal mask and context link. 506 */ 507 if (uc.uc_flags & UC_SIGMASK) { 508 block_all_signals(self); 509 delete_reserved_signals(&uc.uc_sigmask); 510 self->ul_sigmask = uc.uc_sigmask; 511 if (self->ul_cursig) { 512 /* 513 * We have a deferred signal present. 514 * The signal mask will be set when the 515 * signal is taken in take_deferred_signal(). 516 */ 517 ASSERT(self->ul_critical + self->ul_sigdefer != 0); 518 uc.uc_flags &= ~UC_SIGMASK; 519 } 520 } 521 self->ul_siglink = uc.uc_link; 522 523 /* 524 * We don't know where this context structure has been. 525 * Preserve the curthread pointer, at least. 526 * 527 * Allow this feature to be disabled if a particular process 528 * requests it. 529 */ 530 if (setcontext_enforcement) { 531 #if defined(__sparc) 532 uc.uc_mcontext.gregs[REG_G7] = (greg_t)self; 533 #elif defined(__amd64) 534 uc.uc_mcontext.gregs[REG_FS] = (greg_t)self->ul_gs; 535 #elif defined(__i386) 536 uc.uc_mcontext.gregs[GS] = (greg_t)self->ul_gs; 537 #else 538 #error "none of __sparc, __amd64, __i386 defined" 539 #endif 540 } 541 542 /* 543 * Make sure that if we return to a call to __lwp_park() 544 * or ___lwp_cond_wait() that it returns right away 545 * (giving us a spurious wakeup but not a deadlock). 546 */ 547 set_parking_flag(self, 0); 548 self->ul_sp = 0; 549 ret = __setcontext_syscall(&uc); 550 551 /* 552 * It is OK for setcontext() to return if the user has not specified 553 * UC_CPU. 554 */ 555 if (uc.uc_flags & UC_CPU) 556 thr_panic("setcontext(): __setcontext() returned"); 557 return (ret); 558 } 559 560 #pragma weak thr_sigsetmask = _thr_sigsetmask 561 #pragma weak pthread_sigmask = _thr_sigsetmask 562 #pragma weak _pthread_sigmask = _thr_sigsetmask 563 int 564 _thr_sigsetmask(int how, const sigset_t *set, sigset_t *oset) 565 { 566 ulwp_t *self = curthread; 567 sigset_t saveset; 568 569 if (set == NULL) { 570 enter_critical(self); 571 if (oset != NULL) 572 *oset = self->ul_sigmask; 573 exit_critical(self); 574 } else { 575 switch (how) { 576 case SIG_BLOCK: 577 case SIG_UNBLOCK: 578 case SIG_SETMASK: 579 break; 580 default: 581 return (EINVAL); 582 } 583 584 /* 585 * The assignments to self->ul_sigmask must be protected from 586 * signals. The nuances of this code are subtle. Be careful. 587 */ 588 block_all_signals(self); 589 if (oset != NULL) 590 saveset = self->ul_sigmask; 591 switch (how) { 592 case SIG_BLOCK: 593 self->ul_sigmask.__sigbits[0] |= set->__sigbits[0]; 594 self->ul_sigmask.__sigbits[1] |= set->__sigbits[1]; 595 break; 596 case SIG_UNBLOCK: 597 self->ul_sigmask.__sigbits[0] &= ~set->__sigbits[0]; 598 self->ul_sigmask.__sigbits[1] &= ~set->__sigbits[1]; 599 break; 600 case SIG_SETMASK: 601 self->ul_sigmask.__sigbits[0] = set->__sigbits[0]; 602 self->ul_sigmask.__sigbits[1] = set->__sigbits[1]; 603 break; 604 } 605 delete_reserved_signals(&self->ul_sigmask); 606 if (oset != NULL) 607 *oset = saveset; 608 restore_signals(self); 609 } 610 611 return (0); 612 } 613 614 #pragma weak sigprocmask = _sigprocmask 615 int 616 _sigprocmask(int how, const sigset_t *set, sigset_t *oset) 617 { 618 int error; 619 620 /* 621 * Guard against children of vfork(). 622 */ 623 if (curthread->ul_vfork) 624 return (__lwp_sigmask(how, set, oset)); 625 626 if ((error = _thr_sigsetmask(how, set, oset)) != 0) { 627 errno = error; 628 return (-1); 629 } 630 631 return (0); 632 } 633 634 /* 635 * Called at library initialization to set up signal handling. 636 * All we really do is initialize the sig_lock mutexes. 637 * All signal handlers are either SIG_DFL or SIG_IGN on exec(). 638 * However, if any signal handlers were established on alternate 639 * link maps before the primary link map has been initialized, 640 * then inform the kernel of the new sigacthandler. 641 */ 642 void 643 signal_init() 644 { 645 uberdata_t *udp = curthread->ul_uberdata; 646 struct sigaction *sap; 647 struct sigaction act; 648 int sig; 649 650 for (sig = 0; sig < NSIG; sig++) { 651 udp->siguaction[sig].sig_lock.mutex_magic = MUTEX_MAGIC; 652 sap = &udp->siguaction[sig].sig_uaction; 653 if (sap->sa_sigaction != SIG_DFL && 654 sap->sa_sigaction != SIG_IGN && 655 __sigaction(sig, NULL, &act) == 0 && 656 act.sa_sigaction != SIG_DFL && 657 act.sa_sigaction != SIG_IGN) { 658 act = *sap; 659 act.sa_flags &= ~SA_NODEFER; 660 act.sa_sigaction = udp->sigacthandler; 661 act.sa_mask = maskset; 662 (void) __sigaction(sig, &act, NULL); 663 } 664 } 665 } 666 667 /* 668 * Common code for cancelling self in _sigcancel() and pthread_cancel(). 669 * If the thread is at a cancellation point (ul_cancelable) then just 670 * return and let _canceloff() do the exit, else exit immediately if 671 * async mode is in effect. 672 */ 673 void 674 do_sigcancel() 675 { 676 ulwp_t *self = curthread; 677 678 ASSERT(self->ul_critical == 0); 679 ASSERT(self->ul_sigdefer == 0); 680 self->ul_cancel_pending = 1; 681 if (self->ul_cancel_async && 682 !self->ul_cancel_disabled && 683 !self->ul_cancelable) 684 _pthread_exit(PTHREAD_CANCELED); 685 } 686 687 /* 688 * Set up the SIGCANCEL handler for threads cancellation, 689 * needed only when we have more than one thread, 690 * or the SIGAIOCANCEL handler for aio cancellation, 691 * called when aio is initialized, in __uaio_init(). 692 */ 693 void 694 setup_cancelsig(int sig) 695 { 696 uberdata_t *udp = curthread->ul_uberdata; 697 mutex_t *mp = &udp->siguaction[sig].sig_lock; 698 struct sigaction act; 699 700 ASSERT(sig == SIGCANCEL || sig == SIGAIOCANCEL); 701 lmutex_lock(mp); 702 act = udp->siguaction[sig].sig_uaction; 703 lmutex_unlock(mp); 704 if (act.sa_sigaction == SIG_DFL || 705 act.sa_sigaction == SIG_IGN) 706 act.sa_flags = SA_SIGINFO; 707 else { 708 act.sa_flags |= SA_SIGINFO; 709 act.sa_flags &= ~(SA_NODEFER | SA_RESETHAND); 710 } 711 act.sa_sigaction = udp->sigacthandler; 712 act.sa_mask = maskset; 713 (void) __sigaction(sig, &act, NULL); 714 } 715