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 2010 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
25 * Copyright 2015 Joyent, Inc.
26 */
27
28 #include "lint.h"
29 #include <sys/feature_tests.h>
30 /*
31 * setcontext() really can return, if UC_CPU is not specified.
32 * Make the compiler shut up about it.
33 */
34 #if defined(__NORETURN)
35 #undef __NORETURN
36 #endif
37 #define __NORETURN
38 #include "thr_uberdata.h"
39 #include "asyncio.h"
40 #include <signal.h>
41 #include <siginfo.h>
42 #include <sys/systm.h>
43
44 /* maskable signals */
45 const sigset_t maskset = {MASKSET0, MASKSET1, MASKSET2, MASKSET3};
46
47 /*
48 * Return true if the valid signal bits in both sets are the same.
49 */
50 int
51 sigequalset(const sigset_t *s1, const sigset_t *s2)
52 {
53 /*
54 * We only test valid signal bits, not rubbish following MAXSIG
55 * (for speed). Algorithm:
56 * if (s1 & fillset) == (s2 & fillset) then (s1 ^ s2) & fillset == 0
57 */
58 /* see lib/libc/inc/thr_uberdata.h for why this must be true */
59 #if (MAXSIG > (2 * 32) && MAXSIG <= (3 * 32))
60 return (!((s1->__sigbits[0] ^ s2->__sigbits[0]) |
61 (s1->__sigbits[1] ^ s2->__sigbits[1]) |
62 ((s1->__sigbits[2] ^ s2->__sigbits[2]) & FILLSET2)));
63 #else
64 #error "fix me: MAXSIG out of bounds"
65 #endif
66 }
67
68 /*
69 * Common code for calling the user-specified signal handler.
70 */
71 void
72 call_user_handler(int sig, siginfo_t *sip, ucontext_t *ucp)
73 {
74 ulwp_t *self = curthread;
75 uberdata_t *udp = self->ul_uberdata;
76 struct sigaction uact;
77 volatile struct sigaction *sap;
78
79 /*
80 * If we are taking a signal while parked or about to be parked
81 * on __lwp_park() then remove ourself from the sleep queue so
82 * that we can grab locks. The code in mutex_lock_queue() and
83 * cond_wait_common() will detect this and deal with it when
84 * __lwp_park() returns.
85 */
86 unsleep_self();
87 set_parking_flag(self, 0);
88
89 if (__td_event_report(self, TD_CATCHSIG, udp)) {
90 self->ul_td_evbuf.eventnum = TD_CATCHSIG;
91 self->ul_td_evbuf.eventdata = (void *)(intptr_t)sig;
92 tdb_event(TD_CATCHSIG, udp);
93 }
94
95 /*
96 * Get a self-consistent set of flags, handler, and mask
97 * while holding the sig's sig_lock for the least possible time.
98 * We must acquire the sig's sig_lock because some thread running
99 * in sigaction() might be establishing a new signal handler.
100 * The code in sigaction() acquires the writer lock; here
101 * we acquire the readers lock to ehance concurrency in the
102 * face of heavy signal traffic, such as generated by java.
103 *
104 * Locking exceptions:
105 * No locking for a child of vfork().
106 * If the signal is SIGPROF with an si_code of PROF_SIG,
107 * then we assume that this signal was generated by
108 * setitimer(ITIMER_REALPROF) set up by the dbx collector.
109 * If the signal is SIGEMT with an si_code of EMT_CPCOVF,
110 * then we assume that the signal was generated by
111 * a hardware performance counter overflow.
112 * In these cases, assume that we need no locking. It is the
113 * monitoring program's responsibility to ensure correctness.
114 */
115 sap = &udp->siguaction[sig].sig_uaction;
116 if (self->ul_vfork ||
117 (sip != NULL &&
118 ((sig == SIGPROF && sip->si_code == PROF_SIG) ||
119 (sig == SIGEMT && sip->si_code == EMT_CPCOVF)))) {
120 /* we wish this assignment could be atomic */
121 (void) memcpy(&uact, (void *)sap, sizeof (uact));
122 } else {
123 rwlock_t *rwlp = &udp->siguaction[sig].sig_lock;
124 lrw_rdlock(rwlp);
125 (void) memcpy(&uact, (void *)sap, sizeof (uact));
126 if ((sig == SIGCANCEL || sig == SIGAIOCANCEL) &&
127 (sap->sa_flags & SA_RESETHAND))
128 sap->sa_sigaction = SIG_DFL;
129 lrw_unlock(rwlp);
130 }
131
132 /*
133 * Set the proper signal mask and call the user's signal handler.
134 * (We overrode the user-requested signal mask with maskset
135 * so we currently have all blockable signals blocked.)
136 *
137 * We would like to ASSERT() that the signal is not a member of the
138 * signal mask at the previous level (ucp->uc_sigmask) or the specified
139 * signal mask for sigsuspend() or pollsys() (self->ul_tmpmask) but
140 * /proc can override this via PCSSIG, so we don't bother.
141 *
142 * We would also like to ASSERT() that the signal mask at the previous
143 * level equals self->ul_sigmask (maskset for sigsuspend() / pollsys()),
144 * but /proc can change the thread's signal mask via PCSHOLD, so we
145 * don't bother with that either.
146 */
147 ASSERT(ucp->uc_flags & UC_SIGMASK);
148 if (self->ul_sigsuspend) {
149 ucp->uc_sigmask = self->ul_sigmask;
150 self->ul_sigsuspend = 0;
151 /* the sigsuspend() or pollsys() signal mask */
152 sigorset(&uact.sa_mask, &self->ul_tmpmask);
153 } else {
154 /* the signal mask at the previous level */
155 sigorset(&uact.sa_mask, &ucp->uc_sigmask);
156 }
157 if (!(uact.sa_flags & SA_NODEFER)) /* add current signal */
158 (void) sigaddset(&uact.sa_mask, sig);
159 self->ul_sigmask = uact.sa_mask;
160 self->ul_siglink = ucp;
161 (void) __lwp_sigmask(SIG_SETMASK, &uact.sa_mask);
162
163 /*
164 * If this thread has been sent SIGCANCEL from the kernel
165 * or from pthread_cancel(), it is being asked to exit.
166 * The kernel may send SIGCANCEL without a siginfo struct.
167 * If the SIGCANCEL is process-directed (from kill() or
168 * sigqueue()), treat it as an ordinary signal.
169 */
170 if (sig == SIGCANCEL) {
171 if (sip == NULL || SI_FROMKERNEL(sip) ||
172 sip->si_code == SI_LWP) {
173 do_sigcancel();
174 goto out;
175 }
176 /* SIGCANCEL is ignored by default */
177 if (uact.sa_sigaction == SIG_DFL ||
178 uact.sa_sigaction == SIG_IGN)
179 goto out;
180 }
181
182 /*
183 * If this thread has been sent SIGAIOCANCEL (SIGLWP) and
184 * we are an aio worker thread, cancel the aio request.
185 */
186 if (sig == SIGAIOCANCEL) {
187 aio_worker_t *aiowp = pthread_getspecific(_aio_key);
188
189 if (sip != NULL && sip->si_code == SI_LWP && aiowp != NULL)
190 siglongjmp(aiowp->work_jmp_buf, 1);
191 /* SIGLWP is ignored by default */
192 if (uact.sa_sigaction == SIG_DFL ||
193 uact.sa_sigaction == SIG_IGN)
194 goto out;
195 }
196
197 if (!(uact.sa_flags & SA_SIGINFO))
198 sip = NULL;
199 __sighndlr(sig, sip, ucp, uact.sa_sigaction);
200
201 #if defined(sparc) || defined(__sparc)
202 /*
203 * If this is a floating point exception and the queue
204 * is non-empty, pop the top entry from the queue. This
205 * is to maintain expected behavior.
206 */
207 if (sig == SIGFPE && ucp->uc_mcontext.fpregs.fpu_qcnt) {
208 fpregset_t *fp = &ucp->uc_mcontext.fpregs;
209
210 if (--fp->fpu_qcnt > 0) {
211 unsigned char i;
212 struct fq *fqp;
213
214 fqp = fp->fpu_q;
215 for (i = 0; i < fp->fpu_qcnt; i++)
216 fqp[i] = fqp[i+1];
217 }
218 }
219 #endif /* sparc */
220
221 out:
222 (void) setcontext(ucp);
223 thr_panic("call_user_handler(): setcontext() returned");
224 }
225
226 /*
227 * take_deferred_signal() is called when ul_critical and ul_sigdefer become
228 * zero and a deferred signal has been recorded on the current thread.
229 * We are out of the critical region and are ready to take a signal.
230 * The kernel has all signals blocked on this lwp, but our value of
231 * ul_sigmask is the correct signal mask for the previous context.
232 *
233 * We call __sigresend() to atomically restore the signal mask and
234 * cause the signal to be sent again with the remembered siginfo.
235 * We will not return successfully from __sigresend() until the
236 * application's signal handler has been run via sigacthandler().
237 */
238 void
239 take_deferred_signal(int sig)
240 {
241 extern int __sigresend(int, siginfo_t *, sigset_t *);
242 ulwp_t *self = curthread;
243 siguaction_t *suap = &self->ul_uberdata->siguaction[sig];
244 siginfo_t *sip;
245 int error;
246
247 ASSERT((self->ul_critical | self->ul_sigdefer | self->ul_cursig) == 0);
248
249 /*
250 * If the signal handler was established with SA_RESETHAND,
251 * the kernel has reset the handler to SIG_DFL, so we have
252 * to reestablish the handler now so that it will be entered
253 * again when we call __sigresend(), below.
254 *
255 * Logically, we should acquire and release the signal's
256 * sig_lock around this operation to protect the integrity
257 * of the signal action while we copy it, as is done below
258 * in _libc_sigaction(). However, we may be on a user-level
259 * sleep queue at this point and lrw_wrlock(&suap->sig_lock)
260 * might attempt to sleep on a different sleep queue and
261 * that would corrupt the entire sleep queue mechanism.
262 *
263 * If we are on a sleep queue we will remove ourself from
264 * it in call_user_handler(), called from sigacthandler(),
265 * before entering the application's signal handler.
266 * In the meantime, we must not acquire any locks.
267 */
268 if (suap->sig_uaction.sa_flags & SA_RESETHAND) {
269 struct sigaction tact = suap->sig_uaction;
270 tact.sa_flags &= ~SA_NODEFER;
271 tact.sa_sigaction = self->ul_uberdata->sigacthandler;
272 tact.sa_mask = maskset;
273 (void) __sigaction(sig, &tact, NULL);
274 }
275
276 if (self->ul_siginfo.si_signo == 0)
277 sip = NULL;
278 else
279 sip = &self->ul_siginfo;
280
281 /* EAGAIN can happen only for a pending SIGSTOP signal */
282 while ((error = __sigresend(sig, sip, &self->ul_sigmask)) == EAGAIN)
283 continue;
284 if (error)
285 thr_panic("take_deferred_signal(): __sigresend() failed");
286 }
287
288 /*
289 * sigacthandler() attempts to clean up dangling uc_link pointers in
290 * signal handling contexts when libc believes us to have escaped
291 * a signal handler incorrectly in the past.
292 *
293 * Branded processes have a legitimate use for a chain including contexts
294 * other than those used for signal handling when tracking emulation
295 * requests from the kernel. We allow them to disable this cleanup
296 * behaviour.
297 */
298 static int escaped_context_cleanup = 1;
299
300 void
301 set_escaped_context_cleanup(int on)
302 {
303 escaped_context_cleanup = on;
304 }
305
306 void
307 sigacthandler(int sig, siginfo_t *sip, void *uvp)
308 {
309 ucontext_t *ucp = uvp;
310 ulwp_t *self = curthread;
311
312 /*
313 * Do this in case we took a signal while in a cancelable system call.
314 * It does no harm if we were not in such a system call.
315 */
316 self->ul_sp = 0;
317 if (sig != SIGCANCEL)
318 self->ul_cancel_async = self->ul_save_async;
319
320 /*
321 * If this thread has performed a longjmp() from a signal handler
322 * back to main level some time in the past, it has left the kernel
323 * thinking that it is still in the signal context. We repair this
324 * possible damage by setting ucp->uc_link to NULL if we know that
325 * we are actually executing at main level (self->ul_siglink == NULL).
326 * See the code for setjmp()/longjmp() for more details.
327 */
328 if (escaped_context_cleanup && self->ul_siglink == NULL)
329 ucp->uc_link = NULL;
330
331 /*
332 * If we are not in a critical region and are
333 * not deferring signals, take the signal now.
334 */
335 if ((self->ul_critical + self->ul_sigdefer) == 0) {
336 call_user_handler(sig, sip, ucp);
337 /*
338 * On the surface, the following call seems redundant
339 * because call_user_handler() cannot return. However,
340 * we don't want to return from here because the compiler
341 * might recycle our frame. We want to keep it on the
342 * stack to assist debuggers such as pstack in identifying
343 * signal frames. The call to thr_panic() serves to prevent
344 * tail-call optimisation here.
345 */
346 thr_panic("sigacthandler(): call_user_handler() returned");
347 }
348
349 /*
350 * We are in a critical region or we are deferring signals. When
351 * we emerge from the region we will call take_deferred_signal().
352 */
353 ASSERT(self->ul_cursig == 0);
354 self->ul_cursig = (char)sig;
355 if (sip != NULL)
356 (void) memcpy(&self->ul_siginfo,
357 sip, sizeof (siginfo_t));
358 else
359 self->ul_siginfo.si_signo = 0;
360
361 /*
362 * Make sure that if we return to a call to __lwp_park()
363 * or ___lwp_cond_wait() that it returns right away
364 * (giving us a spurious wakeup but not a deadlock).
365 */
366 set_parking_flag(self, 0);
367
368 /*
369 * Return to the previous context with all signals blocked.
370 * We will restore the signal mask in take_deferred_signal().
371 * Note that we are calling the system call trap here, not
372 * the setcontext() wrapper. We don't want to change the
373 * thread's ul_sigmask by this operation.
374 */
375 ucp->uc_sigmask = maskset;
376 (void) __setcontext(ucp);
377 thr_panic("sigacthandler(): __setcontext() returned");
378 }
379
380 #pragma weak _sigaction = sigaction
381 int
382 sigaction(int sig, const struct sigaction *nact, struct sigaction *oact)
383 {
384 ulwp_t *self = curthread;
385 uberdata_t *udp = self->ul_uberdata;
386 struct sigaction oaction;
387 struct sigaction tact;
388 struct sigaction *tactp = NULL;
389 int rv;
390
391 if (sig <= 0 || sig >= NSIG) {
392 errno = EINVAL;
393 return (-1);
394 }
395
396 if (!self->ul_vfork)
397 lrw_wrlock(&udp->siguaction[sig].sig_lock);
398
399 oaction = udp->siguaction[sig].sig_uaction;
400
401 if (nact != NULL) {
402 tact = *nact; /* make a copy so we can modify it */
403 tactp = &tact;
404 delete_reserved_signals(&tact.sa_mask);
405
406 #if !defined(_LP64)
407 tact.sa_resv[0] = tact.sa_resv[1] = 0; /* cleanliness */
408 #endif
409 /*
410 * To be compatible with the behavior of SunOS 4.x:
411 * If the new signal handler is SIG_IGN or SIG_DFL, do
412 * not change the signal's entry in the siguaction array.
413 * This allows a child of vfork(2) to set signal handlers
414 * to SIG_IGN or SIG_DFL without affecting the parent.
415 *
416 * This also covers a race condition with some thread
417 * setting the signal action to SIG_DFL or SIG_IGN
418 * when the thread has also received and deferred
419 * that signal. When the thread takes the deferred
420 * signal, even though it has set the action to SIG_DFL
421 * or SIG_IGN, it will execute the old signal handler
422 * anyway. This is an inherent signaling race condition
423 * and is not a bug.
424 *
425 * A child of vfork() is not allowed to change signal
426 * handlers to anything other than SIG_DFL or SIG_IGN.
427 */
428 if (self->ul_vfork) {
429 if (tact.sa_sigaction != SIG_IGN)
430 tact.sa_sigaction = SIG_DFL;
431 } else if (sig == SIGCANCEL || sig == SIGAIOCANCEL) {
432 /*
433 * Always catch these signals.
434 * We need SIGCANCEL for pthread_cancel() to work.
435 * We need SIGAIOCANCEL for aio_cancel() to work.
436 */
437 udp->siguaction[sig].sig_uaction = tact;
438 if (tact.sa_sigaction == SIG_DFL ||
439 tact.sa_sigaction == SIG_IGN)
440 tact.sa_flags = SA_SIGINFO;
441 else {
442 tact.sa_flags |= SA_SIGINFO;
443 tact.sa_flags &=
444 ~(SA_NODEFER | SA_RESETHAND | SA_RESTART);
445 }
446 tact.sa_sigaction = udp->sigacthandler;
447 tact.sa_mask = maskset;
448 } else if (tact.sa_sigaction != SIG_DFL &&
449 tact.sa_sigaction != SIG_IGN) {
450 udp->siguaction[sig].sig_uaction = tact;
451 tact.sa_flags &= ~SA_NODEFER;
452 tact.sa_sigaction = udp->sigacthandler;
453 tact.sa_mask = maskset;
454 }
455 }
456
457 if ((rv = __sigaction(sig, tactp, oact)) != 0)
458 udp->siguaction[sig].sig_uaction = oaction;
459 else if (oact != NULL &&
460 oact->sa_sigaction != SIG_DFL &&
461 oact->sa_sigaction != SIG_IGN)
462 *oact = oaction;
463
464 /*
465 * We detect setting the disposition of SIGIO just to set the
466 * _sigio_enabled flag for the asynchronous i/o (aio) code.
467 */
468 if (sig == SIGIO && rv == 0 && tactp != NULL) {
469 _sigio_enabled =
470 (tactp->sa_handler != SIG_DFL &&
471 tactp->sa_handler != SIG_IGN);
472 }
473
474 if (!self->ul_vfork)
475 lrw_unlock(&udp->siguaction[sig].sig_lock);
476 return (rv);
477 }
478
479 /*
480 * This is a private interface for the lx brand.
481 */
482 void
483 setsigacthandler(void (*nsigacthandler)(int, siginfo_t *, void *),
484 void (**osigacthandler)(int, siginfo_t *, void *),
485 int (*brsetctxt)(const ucontext_t *))
486 {
487 ulwp_t *self = curthread;
488 uberdata_t *udp = self->ul_uberdata;
489
490 if (osigacthandler != NULL)
491 *osigacthandler = udp->sigacthandler;
492
493 udp->sigacthandler = nsigacthandler;
494
495 if (brsetctxt != NULL)
496 udp->setctxt = brsetctxt;
497 }
498
499 /*
500 * Tell the kernel to block all signals.
501 * Use the schedctl interface, or failing that, use __lwp_sigmask().
502 * This action can be rescinded only by making a system call that
503 * sets the signal mask:
504 * __lwp_sigmask(), __sigprocmask(), __setcontext(),
505 * __sigsuspend() or __pollsys().
506 * In particular, this action cannot be reversed by assigning
507 * scp->sc_sigblock = 0. That would be a way to lose signals.
508 * See the definition of restore_signals(self).
509 */
510 void
511 block_all_signals(ulwp_t *self)
512 {
513 volatile sc_shared_t *scp;
514
515 enter_critical(self);
516 if ((scp = self->ul_schedctl) != NULL ||
517 (scp = setup_schedctl()) != NULL)
518 scp->sc_sigblock = 1;
519 else
520 (void) __lwp_sigmask(SIG_SETMASK, &maskset);
521 exit_critical(self);
522 }
523
524 /*
525 * setcontext() has code that forcibly restores the curthread
526 * pointer in a context passed to the setcontext(2) syscall.
527 *
528 * Certain processes may need to disable this feature, so these routines
529 * provide the mechanism to do so.
530 *
531 * (As an example, branded 32-bit x86 processes may use %gs for their own
532 * purposes, so they need to be able to specify a %gs value to be restored
533 * on return from a signal handler via the passed ucontext_t.)
534 */
535 static int setcontext_enforcement = 1;
536
537 void
538 set_setcontext_enforcement(int on)
539 {
540 setcontext_enforcement = on;
541 }
542
543 /*
544 * The LX brand emulation library implements an operation that is analogous to
545 * setcontext(), but takes a different path in to the kernel. So that it can
546 * correctly restore a signal mask, we expose just the signal mask handling
547 * part of the regular setcontext() routine as a private interface.
548 */
549 void
550 setcontext_sigmask(ucontext_t *ucp)
551 {
552 ulwp_t *self = curthread;
553
554 if (ucp->uc_flags & UC_SIGMASK) {
555 block_all_signals(self);
556 delete_reserved_signals(&ucp->uc_sigmask);
557 self->ul_sigmask = ucp->uc_sigmask;
558 if (self->ul_cursig) {
559 /*
560 * We have a deferred signal present.
561 * The signal mask will be set when the
562 * signal is taken in take_deferred_signal().
563 */
564 ASSERT(self->ul_critical + self->ul_sigdefer != 0);
565 ucp->uc_flags &= ~UC_SIGMASK;
566 }
567 }
568 }
569
570 #pragma weak _setcontext = setcontext
571 int
572 setcontext(const ucontext_t *ucp)
573 {
574 ulwp_t *self = curthread;
575 uberdata_t *udp = self->ul_uberdata;
576 int ret;
577 ucontext_t uc;
578
579 /*
580 * Returning from the main context (uc_link == NULL) causes
581 * the thread to exit. See setcontext(2) and makecontext(3C).
582 */
583 if (ucp == NULL)
584 thr_exit(NULL);
585 (void) memcpy(&uc, ucp, sizeof (uc));
586
587 /*
588 * Restore previous signal mask and context link.
589 */
590 setcontext_sigmask(&uc);
591 self->ul_siglink = uc.uc_link;
592
593 /*
594 * We don't know where this context structure has been.
595 * Preserve the curthread pointer, at least.
596 *
597 * Allow this feature to be disabled if a particular process
598 * requests it.
599 */
600 if (setcontext_enforcement) {
601 #if defined(__sparc)
602 uc.uc_mcontext.gregs[REG_G7] = (greg_t)self;
603 #elif defined(__amd64)
604 uc.uc_mcontext.gregs[REG_FS] = (greg_t)0; /* null for fsbase */
605 #elif defined(__i386)
606 uc.uc_mcontext.gregs[GS] = (greg_t)LWPGS_SEL;
607 #else
608 #error "none of __sparc, __amd64, __i386 defined"
609 #endif
610 }
611
612 /*
613 * Make sure that if we return to a call to __lwp_park()
614 * or ___lwp_cond_wait() that it returns right away
615 * (giving us a spurious wakeup but not a deadlock).
616 */
617 set_parking_flag(self, 0);
618 self->ul_sp = 0;
619 ret = udp->setctxt(&uc);
620
621 /*
622 * It is OK for setcontext() to return if the user has not specified
623 * UC_CPU.
624 */
625 if (uc.uc_flags & UC_CPU)
626 thr_panic("setcontext(): __setcontext() returned");
627 return (ret);
628 }
629
630 #pragma weak _thr_sigsetmask = thr_sigsetmask
631 int
632 thr_sigsetmask(int how, const sigset_t *set, sigset_t *oset)
633 {
634 ulwp_t *self = curthread;
635 sigset_t saveset;
636
637 if (set == NULL) {
638 enter_critical(self);
639 if (oset != NULL)
640 *oset = self->ul_sigmask;
641 exit_critical(self);
642 } else {
643 switch (how) {
644 case SIG_BLOCK:
645 case SIG_UNBLOCK:
646 case SIG_SETMASK:
647 break;
648 default:
649 return (EINVAL);
650 }
651
652 /*
653 * The assignments to self->ul_sigmask must be protected from
654 * signals. The nuances of this code are subtle. Be careful.
655 */
656 block_all_signals(self);
657 if (oset != NULL)
658 saveset = self->ul_sigmask;
659 switch (how) {
660 case SIG_BLOCK:
661 self->ul_sigmask.__sigbits[0] |= set->__sigbits[0];
662 self->ul_sigmask.__sigbits[1] |= set->__sigbits[1];
663 self->ul_sigmask.__sigbits[2] |= set->__sigbits[2];
664 self->ul_sigmask.__sigbits[3] |= set->__sigbits[3];
665 break;
666 case SIG_UNBLOCK:
667 self->ul_sigmask.__sigbits[0] &= ~set->__sigbits[0];
668 self->ul_sigmask.__sigbits[1] &= ~set->__sigbits[1];
669 self->ul_sigmask.__sigbits[2] &= ~set->__sigbits[2];
670 self->ul_sigmask.__sigbits[3] &= ~set->__sigbits[3];
671 break;
672 case SIG_SETMASK:
673 self->ul_sigmask.__sigbits[0] = set->__sigbits[0];
674 self->ul_sigmask.__sigbits[1] = set->__sigbits[1];
675 self->ul_sigmask.__sigbits[2] = set->__sigbits[2];
676 self->ul_sigmask.__sigbits[3] = set->__sigbits[3];
677 break;
678 }
679 delete_reserved_signals(&self->ul_sigmask);
680 if (oset != NULL)
681 *oset = saveset;
682 restore_signals(self);
683 }
684
685 return (0);
686 }
687
688 #pragma weak _pthread_sigmask = pthread_sigmask
689 int
690 pthread_sigmask(int how, const sigset_t *set, sigset_t *oset)
691 {
692 return (thr_sigsetmask(how, set, oset));
693 }
694
695 #pragma weak _sigprocmask = sigprocmask
696 int
697 sigprocmask(int how, const sigset_t *set, sigset_t *oset)
698 {
699 int error;
700
701 /*
702 * Guard against children of vfork().
703 */
704 if (curthread->ul_vfork)
705 return (__sigprocmask(how, set, oset));
706
707 if ((error = thr_sigsetmask(how, set, oset)) != 0) {
708 errno = error;
709 return (-1);
710 }
711
712 return (0);
713 }
714
715 /*
716 * Called at library initialization to set up signal handling.
717 * All we really do is initialize the sig_lock rwlocks.
718 * All signal handlers are either SIG_DFL or SIG_IGN on exec().
719 * However, if any signal handlers were established on alternate
720 * link maps before the primary link map has been initialized,
721 * then inform the kernel of the new sigacthandler.
722 */
723 void
724 signal_init()
725 {
726 uberdata_t *udp = curthread->ul_uberdata;
727 struct sigaction *sap;
728 struct sigaction act;
729 rwlock_t *rwlp;
730 int sig;
731
732 for (sig = 0; sig < NSIG; sig++) {
733 rwlp = &udp->siguaction[sig].sig_lock;
734 rwlp->rwlock_magic = RWL_MAGIC;
735 rwlp->mutex.mutex_flag = LOCK_INITED;
736 rwlp->mutex.mutex_magic = MUTEX_MAGIC;
737 sap = &udp->siguaction[sig].sig_uaction;
738 if (sap->sa_sigaction != SIG_DFL &&
739 sap->sa_sigaction != SIG_IGN &&
740 __sigaction(sig, NULL, &act) == 0 &&
741 act.sa_sigaction != SIG_DFL &&
742 act.sa_sigaction != SIG_IGN) {
743 act = *sap;
744 act.sa_flags &= ~SA_NODEFER;
745 act.sa_sigaction = udp->sigacthandler;
746 act.sa_mask = maskset;
747 (void) __sigaction(sig, &act, NULL);
748 }
749 }
750 }
751
752 /*
753 * Common code for cancelling self in _sigcancel() and pthread_cancel().
754 * First record the fact that a cancellation is pending.
755 * Then, if cancellation is disabled or if we are holding unprotected
756 * libc locks, just return to defer the cancellation.
757 * Then, if we are at a cancellation point (ul_cancelable) just
758 * return and let _canceloff() do the exit.
759 * Else exit immediately if async mode is in effect.
760 */
761 void
762 do_sigcancel(void)
763 {
764 ulwp_t *self = curthread;
765
766 ASSERT(self->ul_critical == 0);
767 ASSERT(self->ul_sigdefer == 0);
768 self->ul_cancel_pending = 1;
769 if (self->ul_cancel_async &&
770 !self->ul_cancel_disabled &&
771 self->ul_libc_locks == 0 &&
772 !self->ul_cancelable)
773 pthread_exit(PTHREAD_CANCELED);
774 set_cancel_pending_flag(self, 0);
775 }
776
777 /*
778 * Set up the SIGCANCEL handler for threads cancellation,
779 * needed only when we have more than one thread,
780 * or the SIGAIOCANCEL handler for aio cancellation,
781 * called when aio is initialized, in __uaio_init().
782 */
783 void
784 setup_cancelsig(int sig)
785 {
786 uberdata_t *udp = curthread->ul_uberdata;
787 rwlock_t *rwlp = &udp->siguaction[sig].sig_lock;
788 struct sigaction act;
789
790 ASSERT(sig == SIGCANCEL || sig == SIGAIOCANCEL);
791 lrw_rdlock(rwlp);
792 act = udp->siguaction[sig].sig_uaction;
793 lrw_unlock(rwlp);
794 if (act.sa_sigaction == SIG_DFL ||
795 act.sa_sigaction == SIG_IGN)
796 act.sa_flags = SA_SIGINFO;
797 else {
798 act.sa_flags |= SA_SIGINFO;
799 act.sa_flags &= ~(SA_NODEFER | SA_RESETHAND | SA_RESTART);
800 }
801 act.sa_sigaction = udp->sigacthandler;
802 act.sa_mask = maskset;
803 (void) __sigaction(sig, &act, NULL);
804 }