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
50struct usigaction {
51	struct sigaction sigact;
52	struct urwlock   lock;
53};
54
55static struct usigaction _thr_sigact[_SIG_MAXSIG];
56
57static void thr_sighandler(int, siginfo_t *, void *);
58static void handle_signal(struct sigaction *, int, siginfo_t *, ucontext_t *);
59static void check_deferred_signal(struct pthread *);
60static void check_suspend(struct pthread *);
61static void check_cancel(struct pthread *curthread, ucontext_t *ucp);
62
63int	___pause(void);
64int	_raise(int);
65int	__sigtimedwait(const sigset_t *set, siginfo_t *info,
66	const struct timespec * timeout);
67int	_sigtimedwait(const sigset_t *set, siginfo_t *info,
68	const struct timespec * timeout);
69int	__sigwaitinfo(const sigset_t *set, siginfo_t *info);
70int	_sigwaitinfo(const sigset_t *set, siginfo_t *info);
71int	___sigwait(const sigset_t *set, int *sig);
72int	_sigwait(const sigset_t *set, int *sig);
73int	__sigsuspend(const sigset_t *sigmask);
74int	_sigaction(int, const struct sigaction *, struct sigaction *);
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,
147	struct sigcontext *scp, 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 = _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
186static void
187handle_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
259void
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 */
271static void
272check_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
316static void
317check_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
345static void
346check_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
397void
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
414void
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;
428retry:
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
452void
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
461void
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
470void
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
479void
480_thr_signal_deinit(void)
481{
482}
483
484__weak_reference(___pause, pause);
485
486int
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
498int
499_raise(int sig)
500{
501	return _thr_send_sig(_get_curthread(), sig);
502}
503
504__weak_reference(_sigaction, sigaction);
505
506int
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
575int
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
593int
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
603int
604_sigsuspend(const sigset_t * set)
605{
606	sigset_t newset;
607
608	return (__sys_sigsuspend(thr_remove_thr_signals(set, &newset)));
609}
610
611int
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
640int
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 */
655int
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
670int
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 */
683int
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
696int
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 */
709int
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);
725int
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);
742int
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