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Move the P_WEXIT check from lwpsignal() to kern_kill(). That is, disallow
[dragonfly/vkernel-mp.git] / sys / kern / kern_sig.c
blob56699bb3b88d9ad4ddab87805aa14f5b969cb6e2
1 /*
2 * Copyright (c) 1982, 1986, 1989, 1991, 1993
3 * The Regents of the University of California. All rights reserved.
4 * (c) UNIX System Laboratories, Inc.
5 * All or some portions of this file are derived from material licensed
6 * to the University of California by American Telephone and Telegraph
7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
8 * the permission of UNIX System Laboratories, Inc.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. All advertising materials mentioning features or use of this software
19 * must display the following acknowledgement:
20 * This product includes software developed by the University of
21 * California, Berkeley and its contributors.
22 * 4. Neither the name of the University nor the names of its contributors
23 * may be used to endorse or promote products derived from this software
24 * without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * SUCH DAMAGE.
37 *
38 * @(#)kern_sig.c 8.7 (Berkeley) 4/18/94
39 * $FreeBSD: src/sys/kern/kern_sig.c,v 1.72.2.17 2003/05/16 16:34:34 obrien Exp $
40 * $DragonFly: src/sys/kern/kern_sig.c,v 1.80 2007/06/30 02:33:04 dillon Exp $
41 */
42
43 #include "opt_ktrace.h"
44
45 #include <sys/param.h>
46 #include <sys/systm.h>
47 #include <sys/kernel.h>
48 #include <sys/sysproto.h>
49 #include <sys/signalvar.h>
50 #include <sys/signal2.h>
51 #include <sys/resourcevar.h>
52 #include <sys/vnode.h>
53 #include <sys/event.h>
54 #include <sys/proc.h>
55 #include <sys/nlookup.h>
56 #include <sys/pioctl.h>
57 #include <sys/systm.h>
58 #include <sys/acct.h>
59 #include <sys/fcntl.h>
60 #include <sys/lock.h>
61 #include <sys/wait.h>
62 #include <sys/ktrace.h>
63 #include <sys/syslog.h>
64 #include <sys/stat.h>
65 #include <sys/sysent.h>
66 #include <sys/sysctl.h>
67 #include <sys/malloc.h>
68 #include <sys/interrupt.h>
69 #include <sys/unistd.h>
70 #include <sys/kern_syscall.h>
71 #include <sys/vkernel.h>
72 #include <sys/thread2.h>
73
74 #include <machine/cpu.h>
75 #include <machine/smp.h>
76
77 static int coredump(struct lwp *, int);
78 static char *expand_name(const char *, uid_t, pid_t);
79 static int dokillpg(int sig, int pgid, int all);
80 static int sig_ffs(sigset_t *set);
81 static int sigprop(int sig);
82 #ifdef SMP
83 static void signotify_remote(void *arg);
84 #endif
85 static int kern_sigtimedwait(sigset_t set, siginfo_t *info,
86 struct timespec *timeout);
87
88 static int filt_sigattach(struct knote *kn);
89 static void filt_sigdetach(struct knote *kn);
90 static int filt_signal(struct knote *kn, long hint);
91
92 struct filterops sig_filtops =
93 { 0, filt_sigattach, filt_sigdetach, filt_signal };
94
95 static int kern_logsigexit = 1;
96 SYSCTL_INT(_kern, KERN_LOGSIGEXIT, logsigexit, CTLFLAG_RW,
97 &kern_logsigexit, 0,
98 "Log processes quitting on abnormal signals to syslog(3)");
99
100 /*
101 * Can process p, with pcred pc, send the signal sig to process q?
102 */
103 #define CANSIGNAL(q, sig) \
104 (!p_trespass(curproc->p_ucred, (q)->p_ucred) || \
105 ((sig) == SIGCONT && (q)->p_session == curproc->p_session))
106
107 /*
108 * Policy -- Can real uid ruid with ucred uc send a signal to process q?
109 */
110 #define CANSIGIO(ruid, uc, q) \
111 ((uc)->cr_uid == 0 || \
112 (ruid) == (q)->p_ucred->cr_ruid || \
113 (uc)->cr_uid == (q)->p_ucred->cr_ruid || \
114 (ruid) == (q)->p_ucred->cr_uid || \
115 (uc)->cr_uid == (q)->p_ucred->cr_uid)
116
117 int sugid_coredump;
118 SYSCTL_INT(_kern, OID_AUTO, sugid_coredump, CTLFLAG_RW,
119 &sugid_coredump, 0, "Enable coredumping set user/group ID processes");
120
121 static int do_coredump = 1;
122 SYSCTL_INT(_kern, OID_AUTO, coredump, CTLFLAG_RW,
123 &do_coredump, 0, "Enable/Disable coredumps");
124
125 /*
126 * Signal properties and actions.
127 * The array below categorizes the signals and their default actions
128 * according to the following properties:
129 */
130 #define SA_KILL 0x01 /* terminates process by default */
131 #define SA_CORE 0x02 /* ditto and coredumps */
132 #define SA_STOP 0x04 /* suspend process */
133 #define SA_TTYSTOP 0x08 /* ditto, from tty */
134 #define SA_IGNORE 0x10 /* ignore by default */
135 #define SA_CONT 0x20 /* continue if suspended */
136 #define SA_CANTMASK 0x40 /* non-maskable, catchable */
137 #define SA_CKPT 0x80 /* checkpoint process */
138
139
140 static int sigproptbl[NSIG] = {
141 SA_KILL, /* SIGHUP */
142 SA_KILL, /* SIGINT */
143 SA_KILL|SA_CORE, /* SIGQUIT */
144 SA_KILL|SA_CORE, /* SIGILL */
145 SA_KILL|SA_CORE, /* SIGTRAP */
146 SA_KILL|SA_CORE, /* SIGABRT */
147 SA_KILL|SA_CORE, /* SIGEMT */
148 SA_KILL|SA_CORE, /* SIGFPE */
149 SA_KILL, /* SIGKILL */
150 SA_KILL|SA_CORE, /* SIGBUS */
151 SA_KILL|SA_CORE, /* SIGSEGV */
152 SA_KILL|SA_CORE, /* SIGSYS */
153 SA_KILL, /* SIGPIPE */
154 SA_KILL, /* SIGALRM */
155 SA_KILL, /* SIGTERM */
156 SA_IGNORE, /* SIGURG */
157 SA_STOP, /* SIGSTOP */
158 SA_STOP|SA_TTYSTOP, /* SIGTSTP */
159 SA_IGNORE|SA_CONT, /* SIGCONT */
160 SA_IGNORE, /* SIGCHLD */
161 SA_STOP|SA_TTYSTOP, /* SIGTTIN */
162 SA_STOP|SA_TTYSTOP, /* SIGTTOU */
163 SA_IGNORE, /* SIGIO */
164 SA_KILL, /* SIGXCPU */
165 SA_KILL, /* SIGXFSZ */
166 SA_KILL, /* SIGVTALRM */
167 SA_KILL, /* SIGPROF */
168 SA_IGNORE, /* SIGWINCH */
169 SA_IGNORE, /* SIGINFO */
170 SA_KILL, /* SIGUSR1 */
171 SA_KILL, /* SIGUSR2 */
172 SA_IGNORE, /* SIGTHR */
173 SA_CKPT, /* SIGCKPT */
174 SA_KILL|SA_CKPT, /* SIGCKPTEXIT */
175 SA_IGNORE,
176 SA_IGNORE,
177 SA_IGNORE,
178 SA_IGNORE,
179 SA_IGNORE,
180 SA_IGNORE,
181 SA_IGNORE,
182 SA_IGNORE,
183 SA_IGNORE,
184 SA_IGNORE,
185 SA_IGNORE,
186 SA_IGNORE,
187 SA_IGNORE,
188 SA_IGNORE,
189 SA_IGNORE,
190 SA_IGNORE,
191 SA_IGNORE,
192 SA_IGNORE,
193 SA_IGNORE,
194 SA_IGNORE,
195 SA_IGNORE,
196 SA_IGNORE,
197 SA_IGNORE,
198 SA_IGNORE,
199 SA_IGNORE,
200 SA_IGNORE,
201 SA_IGNORE,
202 SA_IGNORE,
203 SA_IGNORE,
204 SA_IGNORE,
205
206 };
207
208 static __inline int
209 sigprop(int sig)
210 {
211
212 if (sig > 0 && sig < NSIG)
213 return (sigproptbl[_SIG_IDX(sig)]);
214 return (0);
215 }
216
217 static __inline int
218 sig_ffs(sigset_t *set)
219 {
220 int i;
221
222 for (i = 0; i < _SIG_WORDS; i++)
223 if (set->__bits[i])
224 return (ffs(set->__bits[i]) + (i * 32));
225 return (0);
226 }
227
228 int
229 kern_sigaction(int sig, struct sigaction *act, struct sigaction *oact)
230 {
231 struct thread *td = curthread;
232 struct proc *p = td->td_proc;
233 struct lwp *lp;
234 struct sigacts *ps = p->p_sigacts;
235
236 if (sig <= 0 || sig > _SIG_MAXSIG)
237 return (EINVAL);
238
239 if (oact) {
240 oact->sa_handler = ps->ps_sigact[_SIG_IDX(sig)];
241 oact->sa_mask = ps->ps_catchmask[_SIG_IDX(sig)];
242 oact->sa_flags = 0;
243 if (SIGISMEMBER(ps->ps_sigonstack, sig))
244 oact->sa_flags |= SA_ONSTACK;
245 if (!SIGISMEMBER(ps->ps_sigintr, sig))
246 oact->sa_flags |= SA_RESTART;
247 if (SIGISMEMBER(ps->ps_sigreset, sig))
248 oact->sa_flags |= SA_RESETHAND;
249 if (SIGISMEMBER(ps->ps_signodefer, sig))
250 oact->sa_flags |= SA_NODEFER;
251 if (SIGISMEMBER(ps->ps_siginfo, sig))
252 oact->sa_flags |= SA_SIGINFO;
253 if (SIGISMEMBER(ps->ps_sigmailbox, sig))
254 oact->sa_flags |= SA_MAILBOX;
255 if (sig == SIGCHLD && p->p_sigacts->ps_flag & PS_NOCLDSTOP)
256 oact->sa_flags |= SA_NOCLDSTOP;
257 if (sig == SIGCHLD && p->p_sigacts->ps_flag & PS_NOCLDWAIT)
258 oact->sa_flags |= SA_NOCLDWAIT;
259 }
260 if (act) {
261 /*
262 * Check for invalid requests. KILL and STOP cannot be
263 * caught.
264 */
265 if (sig == SIGKILL || sig == SIGSTOP) {
266 if (act->sa_handler != SIG_DFL)
267 return (EINVAL);
268 #if 0
269 /* (not needed, SIG_DFL forces action to occur) */
270 if (act->sa_flags & SA_MAILBOX)
271 return (EINVAL);
272 #endif
273 }
274
275 /*
276 * Change setting atomically.
277 */
278 crit_enter();
279
280 ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask;
281 SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]);
282 if (act->sa_flags & SA_SIGINFO) {
283 ps->ps_sigact[_SIG_IDX(sig)] =
284 (__sighandler_t *)act->sa_sigaction;
285 SIGADDSET(ps->ps_siginfo, sig);
286 } else {
287 ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler;
288 SIGDELSET(ps->ps_siginfo, sig);
289 }
290 if (!(act->sa_flags & SA_RESTART))
291 SIGADDSET(ps->ps_sigintr, sig);
292 else
293 SIGDELSET(ps->ps_sigintr, sig);
294 if (act->sa_flags & SA_ONSTACK)
295 SIGADDSET(ps->ps_sigonstack, sig);
296 else
297 SIGDELSET(ps->ps_sigonstack, sig);
298 if (act->sa_flags & SA_RESETHAND)
299 SIGADDSET(ps->ps_sigreset, sig);
300 else
301 SIGDELSET(ps->ps_sigreset, sig);
302 if (act->sa_flags & SA_NODEFER)
303 SIGADDSET(ps->ps_signodefer, sig);
304 else
305 SIGDELSET(ps->ps_signodefer, sig);
306 if (act->sa_flags & SA_MAILBOX)
307 SIGADDSET(ps->ps_sigmailbox, sig);
308 else
309 SIGDELSET(ps->ps_sigmailbox, sig);
310 if (sig == SIGCHLD) {
311 if (act->sa_flags & SA_NOCLDSTOP)
312 p->p_sigacts->ps_flag |= PS_NOCLDSTOP;
313 else
314 p->p_sigacts->ps_flag &= ~PS_NOCLDSTOP;
315 if (act->sa_flags & SA_NOCLDWAIT) {
316 /*
317 * Paranoia: since SA_NOCLDWAIT is implemented
318 * by reparenting the dying child to PID 1 (and
319 * trust it to reap the zombie), PID 1 itself
320 * is forbidden to set SA_NOCLDWAIT.
321 */
322 if (p->p_pid == 1)
323 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT;
324 else
325 p->p_sigacts->ps_flag |= PS_NOCLDWAIT;
326 } else {
327 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT;
328 }
329 }
330 /*
331 * Set bit in p_sigignore for signals that are set to SIG_IGN,
332 * and for signals set to SIG_DFL where the default is to
333 * ignore. However, don't put SIGCONT in p_sigignore, as we
334 * have to restart the process.
335 */
336 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN ||
337 (sigprop(sig) & SA_IGNORE &&
338 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)) {
339 /* never to be seen again */
340 SIGDELSET(p->p_siglist, sig);
341 /*
342 * Remove the signal also from the thread lists.
343 */
344 FOREACH_LWP_IN_PROC(lp, p) {
345 SIGDELSET(lp->lwp_siglist, sig);
346 }
347 if (sig != SIGCONT)
348 /* easier in ksignal */
349 SIGADDSET(p->p_sigignore, sig);
350 SIGDELSET(p->p_sigcatch, sig);
351 } else {
352 SIGDELSET(p->p_sigignore, sig);
353 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)
354 SIGDELSET(p->p_sigcatch, sig);
355 else
356 SIGADDSET(p->p_sigcatch, sig);
357 }
358
359 crit_exit();
360 }
361 return (0);
362 }
363
364 int
365 sys_sigaction(struct sigaction_args *uap)
366 {
367 struct sigaction act, oact;
368 struct sigaction *actp, *oactp;
369 int error;
370
371 actp = (uap->act != NULL) ? &act : NULL;
372 oactp = (uap->oact != NULL) ? &oact : NULL;
373 if (actp) {
374 error = copyin(uap->act, actp, sizeof(act));
375 if (error)
376 return (error);
377 }
378 error = kern_sigaction(uap->sig, actp, oactp);
379 if (oactp && !error) {
380 error = copyout(oactp, uap->oact, sizeof(oact));
381 }
382 return (error);
383 }
384
385 /*
386 * Initialize signal state for process 0;
387 * set to ignore signals that are ignored by default.
388 */
389 void
390 siginit(struct proc *p)
391 {
392 int i;
393
394 for (i = 1; i <= NSIG; i++)
395 if (sigprop(i) & SA_IGNORE && i != SIGCONT)
396 SIGADDSET(p->p_sigignore, i);
397 }
398
399 /*
400 * Reset signals for an exec of the specified process.
401 */
402 void
403 execsigs(struct proc *p)
404 {
405 struct sigacts *ps = p->p_sigacts;
406 struct lwp *lp;
407 int sig;
408
409 lp = ONLY_LWP_IN_PROC(p);
410
411 /*
412 * Reset caught signals. Held signals remain held
413 * through p_sigmask (unless they were caught,
414 * and are now ignored by default).
415 */
416 while (SIGNOTEMPTY(p->p_sigcatch)) {
417 sig = sig_ffs(&p->p_sigcatch);
418 SIGDELSET(p->p_sigcatch, sig);
419 if (sigprop(sig) & SA_IGNORE) {
420 if (sig != SIGCONT)
421 SIGADDSET(p->p_sigignore, sig);
422 SIGDELSET(p->p_siglist, sig);
423 SIGDELSET(lp->lwp_siglist, sig);
424 }
425 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
426 }
427
428 /*
429 * Reset stack state to the user stack.
430 * Clear set of signals caught on the signal stack.
431 */
432 lp->lwp_sigstk.ss_flags = SS_DISABLE;
433 lp->lwp_sigstk.ss_size = 0;
434 lp->lwp_sigstk.ss_sp = 0;
435 lp->lwp_flag &= ~LWP_ALTSTACK;
436 /*
437 * Reset no zombies if child dies flag as Solaris does.
438 */
439 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT;
440 }
441
442 /*
443 * kern_sigprocmask() - MP SAFE ONLY IF p == curproc
444 *
445 * Manipulate signal mask. This routine is MP SAFE *ONLY* if
446 * p == curproc.
447 */
448 int
449 kern_sigprocmask(int how, sigset_t *set, sigset_t *oset)
450 {
451 struct thread *td = curthread;
452 struct lwp *lp = td->td_lwp;
453 int error;
454
455 if (oset != NULL)
456 *oset = lp->lwp_sigmask;
457
458 error = 0;
459 if (set != NULL) {
460 switch (how) {
461 case SIG_BLOCK:
462 SIG_CANTMASK(*set);
463 SIGSETOR(lp->lwp_sigmask, *set);
464 break;
465 case SIG_UNBLOCK:
466 SIGSETNAND(lp->lwp_sigmask, *set);
467 break;
468 case SIG_SETMASK:
469 SIG_CANTMASK(*set);
470 lp->lwp_sigmask = *set;
471 break;
472 default:
473 error = EINVAL;
474 break;
475 }
476 }
477 return (error);
478 }
479
480 /*
481 * sigprocmask() - MP SAFE
482 */
483 int
484 sys_sigprocmask(struct sigprocmask_args *uap)
485 {
486 sigset_t set, oset;
487 sigset_t *setp, *osetp;
488 int error;
489
490 setp = (uap->set != NULL) ? &set : NULL;
491 osetp = (uap->oset != NULL) ? &oset : NULL;
492 if (setp) {
493 error = copyin(uap->set, setp, sizeof(set));
494 if (error)
495 return (error);
496 }
497 error = kern_sigprocmask(uap->how, setp, osetp);
498 if (osetp && !error) {
499 error = copyout(osetp, uap->oset, sizeof(oset));
500 }
501 return (error);
502 }
503
504 int
505 kern_sigpending(struct __sigset *set)
506 {
507 struct lwp *lp = curthread->td_lwp;
508
509 *set = lwp_sigpend(lp);
510
511 return (0);
512 }
513
514 int
515 sys_sigpending(struct sigpending_args *uap)
516 {
517 sigset_t set;
518 int error;
519
520 error = kern_sigpending(&set);
521
522 if (error == 0)
523 error = copyout(&set, uap->set, sizeof(set));
524 return (error);
525 }
526
527 /*
528 * Suspend process until signal, providing mask to be set
529 * in the meantime.
530 */
531 int
532 kern_sigsuspend(struct __sigset *set)
533 {
534 struct thread *td = curthread;
535 struct lwp *lp = td->td_lwp;
536 struct proc *p = td->td_proc;
537 struct sigacts *ps = p->p_sigacts;
538
539 /*
540 * When returning from sigsuspend, we want
541 * the old mask to be restored after the
542 * signal handler has finished. Thus, we
543 * save it here and mark the sigacts structure
544 * to indicate this.
545 */
546 lp->lwp_oldsigmask = lp->lwp_sigmask;
547 lp->lwp_flag |= LWP_OLDMASK;
548
549 SIG_CANTMASK(*set);
550 lp->lwp_sigmask = *set;
551 while (tsleep(ps, PCATCH, "pause", 0) == 0)
552 /* void */;
553 /* always return EINTR rather than ERESTART... */
554 return (EINTR);
555 }
556
557 /*
558 * Note nonstandard calling convention: libc stub passes mask, not
559 * pointer, to save a copyin.
560 */
561 int
562 sys_sigsuspend(struct sigsuspend_args *uap)
563 {
564 sigset_t mask;
565 int error;
566
567 error = copyin(uap->sigmask, &mask, sizeof(mask));
568 if (error)
569 return (error);
570
571 error = kern_sigsuspend(&mask);
572
573 return (error);
574 }
575
576 int
577 kern_sigaltstack(struct sigaltstack *ss, struct sigaltstack *oss)
578 {
579 struct thread *td = curthread;
580 struct lwp *lp = td->td_lwp;
581 struct proc *p = td->td_proc;
582
583 if ((lp->lwp_flag & LWP_ALTSTACK) == 0)
584 lp->lwp_sigstk.ss_flags |= SS_DISABLE;
585
586 if (oss)
587 *oss = lp->lwp_sigstk;
588
589 if (ss) {
590 if (ss->ss_flags & SS_DISABLE) {
591 if (lp->lwp_sigstk.ss_flags & SS_ONSTACK)
592 return (EINVAL);
593 lp->lwp_flag &= ~LWP_ALTSTACK;
594 lp->lwp_sigstk.ss_flags = ss->ss_flags;
595 } else {
596 if (ss->ss_size < p->p_sysent->sv_minsigstksz)
597 return (ENOMEM);
598 lp->lwp_flag |= LWP_ALTSTACK;
599 lp->lwp_sigstk = *ss;
600 }
601 }
602
603 return (0);
604 }
605
606 int
607 sys_sigaltstack(struct sigaltstack_args *uap)
608 {
609 stack_t ss, oss;
610 int error;
611
612 if (uap->ss) {
613 error = copyin(uap->ss, &ss, sizeof(ss));
614 if (error)
615 return (error);
616 }
617
618 error = kern_sigaltstack(uap->ss ? &ss : NULL,
619 uap->oss ? &oss : NULL);
620
621 if (error == 0 && uap->oss)
622 error = copyout(&oss, uap->oss, sizeof(*uap->oss));
623 return (error);
624 }
625
626 /*
627 * Common code for kill process group/broadcast kill.
628 * cp is calling process.
629 */
630 struct killpg_info {
631 int nfound;
632 int sig;
633 };
634
635 static int killpg_all_callback(struct proc *p, void *data);
636
637 static int
638 dokillpg(int sig, int pgid, int all)
639 {
640 struct killpg_info info;
641 struct proc *cp = curproc;
642 struct proc *p;
643 struct pgrp *pgrp;
644
645 info.nfound = 0;
646 info.sig = sig;
647
648 if (all) {
649 /*
650 * broadcast
651 */
652 allproc_scan(killpg_all_callback, &info);
653 } else {
654 if (pgid == 0) {
655 /*
656 * zero pgid means send to my process group.
657 */
658 pgrp = cp->p_pgrp;
659 } else {
660 pgrp = pgfind(pgid);
661 if (pgrp == NULL)
662 return (ESRCH);
663 }
664 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE);
665 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
666 if (p->p_pid <= 1 ||
667 p->p_stat == SZOMB ||
668 (p->p_flag & P_SYSTEM) ||
669 !CANSIGNAL(p, sig)) {
670 continue;
671 }
672 ++info.nfound;
673 if (sig)
674 ksignal(p, sig);
675 }
676 lockmgr(&pgrp->pg_lock, LK_RELEASE);
677 }
678 return (info.nfound ? 0 : ESRCH);
679 }
680
681 static int
682 killpg_all_callback(struct proc *p, void *data)
683 {
684 struct killpg_info *info = data;
685
686 if (p->p_pid <= 1 || (p->p_flag & P_SYSTEM) ||
687 p == curproc || !CANSIGNAL(p, info->sig)) {
688 return (0);
689 }
690 ++info->nfound;
691 if (info->sig)
692 ksignal(p, info->sig);
693 return(0);
694 }
695
696 /*
697 * Send a general signal to a process or LWPs within that process. Note
698 * that new signals cannot be sent if a process is exiting.
699 */
700 int
701 kern_kill(int sig, pid_t pid, lwpid_t tid)
702 {
703 struct thread *td = curthread;
704 struct proc *p = td->td_proc;
705 struct lwp *lp = NULL;
706
707 if ((u_int)sig > _SIG_MAXSIG)
708 return (EINVAL);
709 if (pid > 0) {
710 /* kill single process */
711 if ((p = pfind(pid)) == NULL)
712 return (ESRCH);
713 if (!CANSIGNAL(p, sig))
714 return (EPERM);
715
716 /*
717 * NOP if the process is exiting. Note that lwpsignal() is
718 * called directly with P_WEXIT set to kill individual LWPs
719 * during exit, which is allowed.
720 */
721 if (p->p_flag & P_WEXIT)
722 return (0);
723 if (tid != -1) {
724 FOREACH_LWP_IN_PROC(lp, p) {
725 if (lp->lwp_tid == tid)
726 break;
727 }
728 if (lp == NULL)
729 return (ESRCH);
730 }
731 if (sig)
732 lwpsignal(p, lp, sig);
733 return (0);
734 }
735 /*
736 * If we come here, pid is a special broadcast pid.
737 * This doesn't mix with a tid.
738 */
739 if (tid != -1)
740 return (EINVAL);
741 switch (pid) {
742 case -1: /* broadcast signal */
743 return (dokillpg(sig, 0, 1));
744 case 0: /* signal own process group */
745 return (dokillpg(sig, 0, 0));
746 default: /* negative explicit process group */
747 return (dokillpg(sig, -pid, 0));
748 }
749 /* NOTREACHED */
750 }
751
752 int
753 sys_kill(struct kill_args *uap)
754 {
755 int error;
756
757 error = kern_kill(uap->signum, uap->pid, -1);
758 return (error);
759 }
760
761 int
762 sys_lwp_kill(struct lwp_kill_args *uap)
763 {
764 int error;
765 pid_t pid = uap->pid;
766
767 /*
768 * A tid is mandatory for lwp_kill(), otherwise
769 * you could simply use kill().
770 */
771 if (uap->tid == -1)
772 return (EINVAL);
773
774 /*
775 * To save on a getpid() function call for intra-process
776 * signals, pid == -1 means current process.
777 */
778 if (pid == -1)
779 pid = curproc->p_pid;
780
781 error = kern_kill(uap->signum, pid, uap->tid);
782 return (error);
783 }
784
785 /*
786 * Send a signal to a process group.
787 */
788 void
789 gsignal(int pgid, int sig)
790 {
791 struct pgrp *pgrp;
792
793 if (pgid && (pgrp = pgfind(pgid)))
794 pgsignal(pgrp, sig, 0);
795 }
796
797 /*
798 * Send a signal to a process group. If checktty is 1,
799 * limit to members which have a controlling terminal.
800 *
801 * pg_lock interlocks against a fork that might be in progress, to
802 * ensure that the new child process picks up the signal.
803 */
804 void
805 pgsignal(struct pgrp *pgrp, int sig, int checkctty)
806 {
807 struct proc *p;
808
809 if (pgrp) {
810 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE);
811 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
812 if (checkctty == 0 || p->p_flag & P_CONTROLT)
813 ksignal(p, sig);
814 }
815 lockmgr(&pgrp->pg_lock, LK_RELEASE);
816 }
817 }
818
819 /*
820 * Send a signal caused by a trap to the current process.
821 * If it will be caught immediately, deliver it with correct code.
822 * Otherwise, post it normally.
823 */
824 void
825 trapsignal(struct lwp *lp, int sig, u_long code)
826 {
827 struct proc *p = lp->lwp_proc;
828 struct sigacts *ps = p->p_sigacts;
829
830 /*
831 * If we are a virtual kernel running an emulated user process
832 * context, switch back to the virtual kernel context before
833 * trying to post the signal.
834 */
835 if (lp->lwp_ve) {
836 struct trapframe *tf = lp->lwp_md.md_regs;
837 tf->tf_trapno = 0;
838 vkernel_trap(lp, tf);
839 }
840
841
842 if ((p->p_flag & P_TRACED) == 0 && SIGISMEMBER(p->p_sigcatch, sig) &&
843 !SIGISMEMBER(lp->lwp_sigmask, sig)) {
844 lp->lwp_ru.ru_nsignals++;
845 #ifdef KTRACE
846 if (KTRPOINT(lp->lwp_thread, KTR_PSIG))
847 ktrpsig(p, sig, ps->ps_sigact[_SIG_IDX(sig)],
848 &lp->lwp_sigmask, code);
849 #endif
850 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)], sig,
851 &lp->lwp_sigmask, code);
852 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]);
853 if (!SIGISMEMBER(ps->ps_signodefer, sig))
854 SIGADDSET(lp->lwp_sigmask, sig);
855 if (SIGISMEMBER(ps->ps_sigreset, sig)) {
856 /*
857 * See kern_sigaction() for origin of this code.
858 */
859 SIGDELSET(p->p_sigcatch, sig);
860 if (sig != SIGCONT &&
861 sigprop(sig) & SA_IGNORE)
862 SIGADDSET(p->p_sigignore, sig);
863 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
864 }
865 } else {
866 lp->lwp_code = code; /* XXX for core dump/debugger */
867 lp->lwp_sig = sig; /* XXX to verify code */
868 lwpsignal(p, lp, sig);
869 }
870 }
871
872 /*
873 * Find a suitable lwp to deliver the signal to.
874 *
875 * Returns NULL if all lwps hold the signal blocked.
876 */
877 static struct lwp *
878 find_lwp_for_signal(struct proc *p, int sig)
879 {
880 struct lwp *lp;
881 struct lwp *run, *sleep, *stop;
882
883 /*
884 * If the running/preempted thread belongs to the proc to which
885 * the signal is being delivered and this thread does not block
886 * the signal, then we can avoid a context switch by delivering
887 * the signal to this thread, because it will return to userland
888 * soon anyways.
889 */
890 lp = lwkt_preempted_proc();
891 if (lp != NULL && lp->lwp_proc == p && !SIGISMEMBER(lp->lwp_sigmask, sig))
892 return (lp);
893
894 run = sleep = stop = NULL;
895 FOREACH_LWP_IN_PROC(lp, p) {
896 /*
897 * If the signal is being blocked by the lwp, then this
898 * lwp is not eligible for receiving the signal.
899 */
900 if (SIGISMEMBER(lp->lwp_sigmask, sig))
901 continue;
902
903 switch (lp->lwp_stat) {
904 case LSRUN:
905 run = lp;
906 break;
907
908 case LSSTOP:
909 stop = lp;
910 break;
911
912 case LSSLEEP:
913 if (lp->lwp_flag & LWP_SINTR)
914 sleep = lp;
915 break;
916 }
917 }
918
919 if (run != NULL)
920 return (run);
921 else if (sleep != NULL)
922 return (sleep);
923 else
924 return (stop);
925 }
926
927 /*
928 * Send the signal to the process. If the signal has an action, the action
929 * is usually performed by the target process rather than the caller; we add
930 * the signal to the set of pending signals for the process.
931 *
932 * Exceptions:
933 * o When a stop signal is sent to a sleeping process that takes the
934 * default action, the process is stopped without awakening it.
935 * o SIGCONT restarts stopped processes (or puts them back to sleep)
936 * regardless of the signal action (eg, blocked or ignored).
937 *
938 * Other ignored signals are discarded immediately.
939 */
940 void
941 ksignal(struct proc *p, int sig)
942 {
943 lwpsignal(p, NULL, sig);
944 }
945
946 /*
947 * The core for ksignal. lp may be NULL, then a suitable thread
948 * will be chosen. If not, lp MUST be a member of p.
949 */
950 void
951 lwpsignal(struct proc *p, struct lwp *lp, int sig)
952 {
953 int prop;
954 sig_t action;
955
956 if (sig > _SIG_MAXSIG || sig <= 0) {
957 kprintf("lwpsignal: signal %d\n", sig);
958 panic("lwpsignal signal number");
959 }
960
961 KKASSERT(lp == NULL || lp->lwp_proc == p);
962
963 crit_enter();
964 KNOTE(&p->p_klist, NOTE_SIGNAL | sig);
965 crit_exit();
966
967 prop = sigprop(sig);
968
969 /*
970 * If proc is traced, always give parent a chance;
971 * if signal event is tracked by procfs, give *that*
972 * a chance, as well.
973 */
974 if ((p->p_flag & P_TRACED) || (p->p_stops & S_SIG)) {
975 action = SIG_DFL;
976 } else {
977 /*
978 * Do not try to deliver signals to an exiting lwp. Note
979 * that we must still deliver the signal if P_WEXIT is set
980 * in the process flags.
981 */
982 if (lp && (lp->lwp_flag & LWP_WEXIT))
983 return;
984
985 /*
986 * Ig the signal is being ignored, then we forget about
987 * it immediately. NOTE: We don't set SIGCONT in p_sigignore,
988 * and if it is set to SIG_IGN, action will be SIG_DFL here.
989 */
990 if (SIGISMEMBER(p->p_sigignore, sig))
991 return;
992 if (SIGISMEMBER(p->p_sigcatch, sig))
993 action = SIG_CATCH;
994 else
995 action = SIG_DFL;
996 }
997
998 /*
999 * If continuing, clear any pending STOP signals.
1000 */
1001 if (prop & SA_CONT)
1002 SIG_STOPSIGMASK(p->p_siglist);
1003
1004 if (prop & SA_STOP) {
1005 /*
1006 * If sending a tty stop signal to a member of an orphaned
1007 * process group, discard the signal here if the action
1008 * is default; don't stop the process below if sleeping,
1009 * and don't clear any pending SIGCONT.
1010 */
1011 if (prop & SA_TTYSTOP && p->p_pgrp->pg_jobc == 0 &&
1012 action == SIG_DFL) {
1013 return;
1014 }
1015 SIG_CONTSIGMASK(p->p_siglist);
1016 }
1017
1018 crit_enter();
1019
1020 if (p->p_stat == SSTOP) {
1021 /*
1022 * Nobody can handle this signal, so add it to the process
1023 * pending list.
1024 */
1025 SIGADDSET(p->p_siglist, sig);
1026
1027 /*
1028 * If the process is stopped and is being traced, then no
1029 * further action is necessary.
1030 */
1031 if (p->p_flag & P_TRACED)
1032 goto out;
1033
1034 /*
1035 * If the process is stopped and receives a KILL signal,
1036 * make the process runnable.
1037 */
1038 if (sig == SIGKILL) {
1039 proc_unstop(p);
1040 goto active_process;
1041 }
1042
1043 /*
1044 * If the process is stopped and receives a CONT signal,
1045 * then try to make the process runnable again.
1046 */
1047 if (prop & SA_CONT) {
1048 /*
1049 * If SIGCONT is default (or ignored), we continue the
1050 * process but don't leave the signal in p_siglist, as
1051 * it has no further action. If SIGCONT is held, we
1052 * continue the process and leave the signal in
1053 * p_siglist. If the process catches SIGCONT, let it
1054 * handle the signal itself.
1055 */
1056 /* XXX what if the signal is being held blocked? */
1057 if (action == SIG_DFL)
1058 SIGDELSET(p->p_siglist, sig);
1059 proc_unstop(p);
1060 if (action == SIG_CATCH)
1061 goto active_process;
1062 goto out;
1063 }
1064
1065 /*
1066 * If the process is stopped and receives another STOP
1067 * signal, we do not need to stop it again. If we did
1068 * the shell could get confused.
1069 *
1070 * However, if the current/preempted lwp is part of the
1071 * process receiving the signal, we need to keep it,
1072 * so that this lwp can stop in issignal() later, as
1073 * we don't want to wait until it reaches userret!
1074 */
1075 if (prop & SA_STOP) {
1076 if (lwkt_preempted_proc() == NULL ||
1077 lwkt_preempted_proc()->lwp_proc != p)
1078 SIGDELSET(p->p_siglist, sig);
1079 }
1080
1081 /*
1082 * Otherwise the process is stopped and it received some
1083 * signal, which does not change its stopped state.
1084 *
1085 * We have to select one thread to set LWP_BREAKTSLEEP,
1086 * so that the current signal will break the sleep
1087 * as soon as a SA_CONT signal will unstop the process.
1088 */
1089 if (lp == NULL)
1090 lp = find_lwp_for_signal(p, sig);
1091 if (lp != NULL &&
1092 (lp->lwp_stat == LSSLEEP || lp->lwp_stat == LSSTOP))
1093 lp->lwp_flag |= LWP_BREAKTSLEEP;
1094 goto out;
1095
1096 /* NOTREACHED */
1097 }
1098 /* else not stopped */
1099 active_process:
1100
1101 if (lp == NULL)
1102 lp = find_lwp_for_signal(p, sig);
1103
1104 /*
1105 * If lp == NULL, there is no thread available which does
1106 * not block the signal. If lp is set, it might be a thread
1107 * specific signal, so we have to check for the thread ignoring
1108 * the signal.
1109 *
1110 * If so, defer further processing for this signal.
1111 * Add the signal to the process pending list.
1112 */
1113 if (lp == NULL || SIGISMEMBER(lp->lwp_sigmask, sig)) {
1114 SIGADDSET(p->p_siglist, sig);
1115 goto out;
1116 }
1117 /* else we have a lwp to deliver the signal to */
1118
1119 if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) &&
1120 (p->p_flag & P_TRACED) == 0) {
1121 p->p_nice = NZERO;
1122 }
1123
1124 /*
1125 * If the process receives a STOP signal which indeed needs to
1126 * stop the process, do so. If the process chose to catch the
1127 * signal, it will be treated like any other signal.
1128 */
1129 if ((prop & SA_STOP) && action == SIG_DFL) {
1130 /*
1131 * If a child holding parent blocked, stopping
1132 * could cause deadlock. Take no action at this
1133 * time.
1134 */
1135 if (p->p_flag & P_PPWAIT) {
1136 SIGADDSET(p->p_siglist, sig);
1137 goto out;
1138 }
1139
1140 /*
1141 * Do not actually try to manipulate the process, but simply
1142 * stop it. Lwps will stop as soon as they safely can.
1143 */
1144 p->p_xstat = sig;
1145 proc_stop(p);
1146 goto out;
1147 }
1148
1149 /*
1150 * If it is a CONT signal with default action, just ignore it.
1151 */
1152 if ((prop & SA_CONT) && action == SIG_DFL)
1153 goto out;
1154
1155 /*
1156 * Mark signal pending at this specific thread.
1157 */
1158 SIGADDSET(lp->lwp_siglist, sig);
1159
1160 lwp_signotify(lp);
1161
1162 out:
1163 crit_exit();
1164 }
1165
1166 void
1167 lwp_signotify(struct lwp *lp)
1168 {
1169 crit_enter();
1170 if (lp->lwp_stat == LSSLEEP || lp->lwp_stat == LSSTOP) {
1171 /*
1172 * Thread is in tsleep.
1173 */
1174
1175 /*
1176 * If the thread is sleeping uninterruptibly
1177 * we can't interrupt the sleep... the signal will
1178 * be noticed when the lwp returns through
1179 * trap() or syscall().
1180 *
1181 * Otherwise the signal can interrupt the sleep.
1182 *
1183 * If the process is traced, the lwp will handle the
1184 * tracing in issignal() when it returns to userland.
1185 */
1186 if (lp->lwp_flag & LWP_SINTR) {
1187 /*
1188 * Make runnable and break out of any tsleep as well.
1189 */
1190 lp->lwp_flag |= LWP_BREAKTSLEEP;
1191 setrunnable(lp);
1192 }
1193 } else {
1194 /*
1195 * Otherwise the thread is running
1196 *
1197 * LSRUN does nothing with the signal, other than kicking
1198 * ourselves if we are running.
1199 * SZOMB and SIDL mean that it will either never be noticed,
1200 * or noticed very soon.
1201 *
1202 * Note that lwp_thread may be NULL or may not be completely
1203 * initialized if the process is in the SIDL or SZOMB state.
1204 *
1205 * For SMP we may have to forward the request to another cpu.
1206 * YYY the MP lock prevents the target process from moving
1207 * to another cpu, see kern/kern_switch.c
1208 *
1209 * If the target thread is waiting on its message port,
1210 * wakeup the target thread so it can check (or ignore)
1211 * the new signal. YYY needs cleanup.
1212 */
1213 if (lp == lwkt_preempted_proc()) {
1214 signotify();
1215 } else if (lp->lwp_stat == LSRUN) {
1216 struct thread *td = lp->lwp_thread;
1217 struct proc *p = lp->lwp_proc;
1218
1219 KASSERT(td != NULL,
1220 ("pid %d/%d NULL lwp_thread stat %d flags %08x/%08x",
1221 p->p_pid, lp->lwp_tid, lp->lwp_stat,
1222 p->p_flag, lp->lwp_flag));
1223
1224 /*
1225 * To prevent a MP race with TDF_SINTR we must
1226 * schedule the thread on the correct cpu.
1227 */
1228 #ifdef SMP
1229 if (td->td_gd != mycpu)
1230 lwkt_send_ipiq(td->td_gd, signotify_remote, lp);
1231 else
1232 #endif
1233 if (td->td_flags & TDF_SINTR)
1234 lwkt_schedule(td);
1235 }
1236 }
1237 crit_exit();
1238 }
1239
1240 #ifdef SMP
1241
1242 /*
1243 * This function is called via an IPI. We will be in a critical section but
1244 * the MP lock will NOT be held. Also note that by the time the ipi message
1245 * gets to us the process 'p' (arg) may no longer be scheduled or even valid.
1246 */
1247 static void
1248 signotify_remote(void *arg)
1249 {
1250 struct lwp *lp = arg;
1251
1252 if (lp == lwkt_preempted_proc()) {
1253 signotify();
1254 } else {
1255 struct thread *td = lp->lwp_thread;
1256 if (td->td_flags & TDF_SINTR)
1257 lwkt_schedule(td);
1258 }
1259 }
1260
1261 #endif
1262
1263 void
1264 proc_stop(struct proc *p)
1265 {
1266 struct lwp *lp;
1267
1268 /* If somebody raced us, be happy with it */
1269 if (p->p_stat == SSTOP)
1270 return;
1271
1272 crit_enter();
1273 p->p_stat = SSTOP;
1274
1275 FOREACH_LWP_IN_PROC(lp, p) {
1276 switch (lp->lwp_stat) {
1277 case LSSTOP:
1278 /*
1279 * Do nothing, we are already counted in
1280 * p_nstopped.
1281 */
1282 break;
1283
1284 case LSSLEEP:
1285 /*
1286 * We're sleeping, but we will stop before
1287 * returning to userspace, so count us
1288 * as stopped as well. We set LWP_WSTOP
1289 * to signal the lwp that it should not
1290 * increase p_nstopped when reaching tstop().
1291 */
1292 if ((lp->lwp_flag & LWP_WSTOP) == 0) {
1293 lp->lwp_flag |= LWP_WSTOP;
1294 ++p->p_nstopped;
1295 }
1296 break;
1297
1298 case LSRUN:
1299 /*
1300 * We might notify ourself, but that's not
1301 * a problem.
1302 */
1303 lwp_signotify(lp);
1304 break;
1305 }
1306 }
1307
1308 if (p->p_nstopped == p->p_nthreads) {
1309 p->p_flag &= ~P_WAITED;
1310 wakeup(p->p_pptr);
1311 if ((p->p_pptr->p_sigacts->ps_flag & PS_NOCLDSTOP) == 0)
1312 ksignal(p->p_pptr, SIGCHLD);
1313 }
1314 crit_exit();
1315 }
1316
1317 void
1318 proc_unstop(struct proc *p)
1319 {
1320 struct lwp *lp;
1321
1322 if (p->p_stat != SSTOP)
1323 return;
1324
1325 crit_enter();
1326 p->p_stat = SACTIVE;
1327
1328 FOREACH_LWP_IN_PROC(lp, p) {
1329 switch (lp->lwp_stat) {
1330 case LSRUN:
1331 /*
1332 * Uh? Not stopped? Well, I guess that's okay.
1333 */
1334 if (bootverbose)
1335 kprintf("proc_unstop: lwp %d/%d not sleeping\n",
1336 p->p_pid, lp->lwp_tid);
1337 break;
1338
1339 case LSSLEEP:
1340 /*
1341 * Still sleeping. Don't bother waking it up.
1342 * However, if this thread was counted as
1343 * stopped, undo this.
1344 *
1345 * Nevertheless we call setrunnable() so that it
1346 * will wake up in case a signal or timeout arrived
1347 * in the meantime.
1348 */
1349 if (lp->lwp_flag & LWP_WSTOP) {
1350 --p->p_nstopped;
1351 } else {
1352 if (bootverbose)
1353 kprintf("proc_unstop: lwp %d/%d sleeping, not stopped\n",
1354 p->p_pid, lp->lwp_tid);
1355 }
1356 /* FALLTHROUGH */
1357
1358 case LSSTOP:
1359 setrunnable(lp);
1360 break;
1361
1362 }
1363 lp->lwp_flag &= ~LWP_WSTOP;
1364 }
1365 crit_exit();
1366 }
1367
1368 static int
1369 kern_sigtimedwait(sigset_t waitset, siginfo_t *info, struct timespec *timeout)
1370 {
1371 sigset_t savedmask, set;
1372 struct proc *p = curproc;
1373 struct lwp *lp = curthread->td_lwp;
1374 int error, sig, hz, timevalid = 0;
1375 struct timespec rts, ets, ts;
1376 struct timeval tv;
1377
1378 error = 0;
1379 sig = 0;
1380 SIG_CANTMASK(waitset);
1381 savedmask = lp->lwp_sigmask;
1382
1383 if (timeout) {
1384 if (timeout->tv_sec >= 0 && timeout->tv_nsec >= 0 &&
1385 timeout->tv_nsec < 1000000000) {
1386 timevalid = 1;
1387 getnanouptime(&rts);
1388 ets = rts;
1389 timespecadd(&ets, timeout);
1390 }
1391 }
1392
1393 for (;;) {
1394 set = lwp_sigpend(lp);
1395 SIGSETAND(set, waitset);
1396 if ((sig = sig_ffs(&set)) != 0) {
1397 SIGFILLSET(lp->lwp_sigmask);
1398 SIGDELSET(lp->lwp_sigmask, sig);
1399 SIG_CANTMASK(lp->lwp_sigmask);
1400 sig = issignal(lp);
1401 /*
1402 * It may be a STOP signal, in the case, issignal
1403 * returns 0, because we may stop there, and new
1404 * signal can come in, we should restart if we got
1405 * nothing.
1406 */
1407 if (sig == 0)
1408 continue;
1409 else
1410 break;
1411 }
1412
1413 /*
1414 * Previous checking got nothing, and we retried but still
1415 * got nothing, we should return the error status.
1416 */
1417 if (error)
1418 break;
1419
1420 /*
1421 * POSIX says this must be checked after looking for pending
1422 * signals.
1423 */
1424 if (timeout) {
1425 if (!timevalid) {
1426 error = EINVAL;
1427 break;
1428 }
1429 getnanouptime(&rts);
1430 if (timespeccmp(&rts, &ets, >=)) {
1431 error = EAGAIN;
1432 break;
1433 }
1434 ts = ets;
1435 timespecsub(&ts, &rts);
1436 TIMESPEC_TO_TIMEVAL(&tv, &ts);
1437 hz = tvtohz_high(&tv);
1438 } else
1439 hz = 0;
1440
1441 lp->lwp_sigmask = savedmask;
1442 SIGSETNAND(lp->lwp_sigmask, waitset);
1443 /*
1444 * We won't ever be woken up. Instead, our sleep will
1445 * be broken in lwpsignal().
1446 */
1447 error = tsleep(&p->p_sigacts, PCATCH, "sigwt", hz);
1448 if (timeout) {
1449 if (error == ERESTART) {
1450 /* can not restart a timeout wait. */
1451 error = EINTR;
1452 } else if (error == EAGAIN) {
1453 /* will calculate timeout by ourself. */
1454 error = 0;
1455 }
1456 }
1457 /* Retry ... */
1458 }
1459
1460 lp->lwp_sigmask = savedmask;
1461 if (sig) {
1462 error = 0;
1463 bzero(info, sizeof(*info));
1464 info->si_signo = sig;
1465 lwp_delsig(lp, sig); /* take the signal! */
1466
1467 if (sig == SIGKILL)
1468 sigexit(p, sig);
1469 }
1470 return (error);
1471 }
1472
1473 int
1474 sys_sigtimedwait(struct sigtimedwait_args *uap)
1475 {
1476 struct timespec ts;
1477 struct timespec *timeout;
1478 sigset_t set;
1479 siginfo_t info;
1480 int error;
1481
1482 if (uap->timeout) {
1483 error = copyin(uap->timeout, &ts, sizeof(ts));
1484 if (error)
1485 return (error);
1486 timeout = &ts;
1487 } else {
1488 timeout = NULL;
1489 }
1490 error = copyin(uap->set, &set, sizeof(set));
1491 if (error)
1492 return (error);
1493 error = kern_sigtimedwait(set, &info, timeout);
1494 if (error)
1495 return (error);
1496 if (uap->info)
1497 error = copyout(&info, uap->info, sizeof(info));
1498 /* Repost if we got an error. */
1499 /*
1500 * XXX lwp
1501 *
1502 * This could transform a thread-specific signal to another
1503 * thread / process pending signal.
1504 */
1505 if (error)
1506 ksignal(curproc, info.si_signo);
1507 else
1508 uap->sysmsg_result = info.si_signo;
1509 return (error);
1510 }
1511
1512 int
1513 sys_sigwaitinfo(struct sigwaitinfo_args *uap)
1514 {
1515 siginfo_t info;
1516 sigset_t set;
1517 int error;
1518
1519 error = copyin(uap->set, &set, sizeof(set));
1520 if (error)
1521 return (error);
1522 error = kern_sigtimedwait(set, &info, NULL);
1523 if (error)
1524 return (error);
1525 if (uap->info)
1526 error = copyout(&info, uap->info, sizeof(info));
1527 /* Repost if we got an error. */
1528 /*
1529 * XXX lwp
1530 *
1531 * This could transform a thread-specific signal to another
1532 * thread / process pending signal.
1533 */
1534 if (error)
1535 ksignal(curproc, info.si_signo);
1536 else
1537 uap->sysmsg_result = info.si_signo;
1538 return (error);
1539 }
1540
1541 /*
1542 * If the current process has received a signal that would interrupt a
1543 * system call, return EINTR or ERESTART as appropriate.
1544 */
1545 int
1546 iscaught(struct lwp *lp)
1547 {
1548 struct proc *p = lp->lwp_proc;
1549 int sig;
1550
1551 if (p) {
1552 if ((sig = CURSIG(lp)) != 0) {
1553 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig))
1554 return (EINTR);
1555 return (ERESTART);
1556 }
1557 }
1558 return(EWOULDBLOCK);
1559 }
1560
1561 /*
1562 * If the current process has received a signal (should be caught or cause
1563 * termination, should interrupt current syscall), return the signal number.
1564 * Stop signals with default action are processed immediately, then cleared;
1565 * they aren't returned. This is checked after each entry to the system for
1566 * a syscall or trap (though this can usually be done without calling issignal
1567 * by checking the pending signal masks in the CURSIG macro.) The normal call
1568 * sequence is
1569 *
1570 * This routine is called via CURSIG/__cursig and the MP lock might not be
1571 * held. Obtain the MP lock for the duration of the operation.
1572 *
1573 * while (sig = CURSIG(curproc))
1574 * postsig(sig);
1575 */
1576 int
1577 issignal(struct lwp *lp)
1578 {
1579 struct proc *p = lp->lwp_proc;
1580 sigset_t mask;
1581 int sig, prop;
1582
1583 get_mplock();
1584 for (;;) {
1585 int traced = (p->p_flag & P_TRACED) || (p->p_stops & S_SIG);
1586
1587 mask = lwp_sigpend(lp);
1588 SIGSETNAND(mask, lp->lwp_sigmask);
1589 if (p->p_flag & P_PPWAIT)
1590 SIG_STOPSIGMASK(mask);
1591 if (SIGISEMPTY(mask)) { /* no signal to send */
1592 rel_mplock();
1593 return (0);
1594 }
1595 sig = sig_ffs(&mask);
1596
1597 STOPEVENT(p, S_SIG, sig);
1598
1599 /*
1600 * We should see pending but ignored signals
1601 * only if P_TRACED was on when they were posted.
1602 */
1603 if (SIGISMEMBER(p->p_sigignore, sig) && (traced == 0)) {
1604 lwp_delsig(lp, sig);
1605 continue;
1606 }
1607 if ((p->p_flag & P_TRACED) && (p->p_flag & P_PPWAIT) == 0) {
1608 /*
1609 * If traced, always stop, and stay stopped until
1610 * released by the parent.
1611 *
1612 * NOTE: SSTOP may get cleared during the loop,
1613 * but we do not re-notify the parent if we have
1614 * to loop several times waiting for the parent
1615 * to let us continue.
1616 *
1617 * XXX not sure if this is still true
1618 */
1619 p->p_xstat = sig;
1620 proc_stop(p);
1621 do {
1622 tstop();
1623 } while (!trace_req(p) && (p->p_flag & P_TRACED));
1624
1625 /*
1626 * If parent wants us to take the signal,
1627 * then it will leave it in p->p_xstat;
1628 * otherwise we just look for signals again.
1629 */
1630 lwp_delsig(lp, sig); /* clear old signal */
1631 sig = p->p_xstat;
1632 if (sig == 0)
1633 continue;
1634
1635 /*
1636 * Put the new signal into p_siglist. If the
1637 * signal is being masked, look for other signals.
1638 *
1639 * XXX lwp might need a call to ksignal()
1640 */
1641 SIGADDSET(p->p_siglist, sig);
1642 if (SIGISMEMBER(lp->lwp_sigmask, sig))
1643 continue;
1644
1645 /*
1646 * If the traced bit got turned off, go back up
1647 * to the top to rescan signals. This ensures
1648 * that p_sig* and ps_sigact are consistent.
1649 */
1650 if ((p->p_flag & P_TRACED) == 0)
1651 continue;
1652 }
1653
1654 prop = sigprop(sig);
1655
1656 /*
1657 * Decide whether the signal should be returned.
1658 * Return the signal's number, or fall through
1659 * to clear it from the pending mask.
1660 */
1661 switch ((int)(intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) {
1662 case (int)SIG_DFL:
1663 /*
1664 * Don't take default actions on system processes.
1665 */
1666 if (p->p_pid <= 1) {
1667 #ifdef DIAGNOSTIC
1668 /*
1669 * Are you sure you want to ignore SIGSEGV
1670 * in init? XXX
1671 */
1672 kprintf("Process (pid %lu) got signal %d\n",
1673 (u_long)p->p_pid, sig);
1674 #endif
1675 break; /* == ignore */
1676 }
1677
1678 /*
1679 * Handle the in-kernel checkpoint action
1680 */
1681 if (prop & SA_CKPT) {
1682 checkpoint_signal_handler(lp);
1683 break;
1684 }
1685
1686 /*
1687 * If there is a pending stop signal to process
1688 * with default action, stop here,
1689 * then clear the signal. However,
1690 * if process is member of an orphaned
1691 * process group, ignore tty stop signals.
1692 */
1693 if (prop & SA_STOP) {
1694 if (p->p_flag & P_TRACED ||
1695 (p->p_pgrp->pg_jobc == 0 &&
1696 prop & SA_TTYSTOP))
1697 break; /* == ignore */
1698 p->p_xstat = sig;
1699 proc_stop(p);
1700 while (p->p_stat == SSTOP) {
1701 tstop();
1702 }
1703 break;
1704 } else if (prop & SA_IGNORE) {
1705 /*
1706 * Except for SIGCONT, shouldn't get here.
1707 * Default action is to ignore; drop it.
1708 */
1709 break; /* == ignore */
1710 } else {
1711 rel_mplock();
1712 return (sig);
1713 }
1714
1715 /*NOTREACHED*/
1716
1717 case (int)SIG_IGN:
1718 /*
1719 * Masking above should prevent us ever trying
1720 * to take action on an ignored signal other
1721 * than SIGCONT, unless process is traced.
1722 */
1723 if ((prop & SA_CONT) == 0 &&
1724 (p->p_flag & P_TRACED) == 0)
1725 kprintf("issignal\n");
1726 break; /* == ignore */
1727
1728 default:
1729 /*
1730 * This signal has an action, let
1731 * postsig() process it.
1732 */
1733 rel_mplock();
1734 return (sig);
1735 }
1736 lwp_delsig(lp, sig); /* take the signal! */
1737 }
1738 /* NOTREACHED */
1739 }
1740
1741 /*
1742 * Take the action for the specified signal
1743 * from the current set of pending signals.
1744 */
1745 void
1746 postsig(int sig)
1747 {
1748 struct lwp *lp = curthread->td_lwp;
1749 struct proc *p = lp->lwp_proc;
1750 struct sigacts *ps = p->p_sigacts;
1751 sig_t action;
1752 sigset_t returnmask;
1753 int code;
1754
1755 KASSERT(sig != 0, ("postsig"));
1756
1757 /*
1758 * If we are a virtual kernel running an emulated user process
1759 * context, switch back to the virtual kernel context before
1760 * trying to post the signal.
1761 */
1762 if (lp->lwp_ve) {
1763 struct trapframe *tf = lp->lwp_md.md_regs;
1764 tf->tf_trapno = 0;
1765 vkernel_trap(lp, tf);
1766 }
1767
1768 lwp_delsig(lp, sig);
1769 action = ps->ps_sigact[_SIG_IDX(sig)];
1770 #ifdef KTRACE
1771 if (KTRPOINT(lp->lwp_thread, KTR_PSIG))
1772 ktrpsig(p, sig, action, lp->lwp_flag & LWP_OLDMASK ?
1773 &lp->lwp_oldsigmask : &lp->lwp_sigmask, 0);
1774 #endif
1775 STOPEVENT(p, S_SIG, sig);
1776
1777 if (action == SIG_DFL) {
1778 /*
1779 * Default action, where the default is to kill
1780 * the process. (Other cases were ignored above.)
1781 */
1782 sigexit(p, sig);
1783 /* NOTREACHED */
1784 } else {
1785 /*
1786 * If we get here, the signal must be caught.
1787 */
1788 KASSERT(action != SIG_IGN && !SIGISMEMBER(lp->lwp_sigmask, sig),
1789 ("postsig action"));
1790
1791 crit_enter();
1792
1793 /*
1794 * Reset the signal handler if asked to
1795 */
1796 if (SIGISMEMBER(ps->ps_sigreset, sig)) {
1797 /*
1798 * See kern_sigaction() for origin of this code.
1799 */
1800 SIGDELSET(p->p_sigcatch, sig);
1801 if (sig != SIGCONT &&
1802 sigprop(sig) & SA_IGNORE)
1803 SIGADDSET(p->p_sigignore, sig);
1804 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
1805 }
1806
1807 /*
1808 * Handle the mailbox case. Copyout to the appropriate
1809 * location but do not generate a signal frame. The system
1810 * call simply returns EINTR and the user is responsible for
1811 * polling the mailbox.
1812 */
1813 if (SIGISMEMBER(ps->ps_sigmailbox, sig)) {
1814 int sig_copy = sig;
1815 copyout(&sig_copy, (void *)action, sizeof(int));
1816 curproc->p_flag |= P_MAILBOX;
1817 crit_exit();
1818 goto done;
1819 }
1820
1821 /*
1822 * Set the signal mask and calculate the mask to restore
1823 * when the signal function returns.
1824 *
1825 * Special case: user has done a sigsuspend. Here the
1826 * current mask is not of interest, but rather the
1827 * mask from before the sigsuspend is what we want
1828 * restored after the signal processing is completed.
1829 */
1830 if (lp->lwp_flag & LWP_OLDMASK) {
1831 returnmask = lp->lwp_oldsigmask;
1832 lp->lwp_flag &= ~LWP_OLDMASK;
1833 } else {
1834 returnmask = lp->lwp_sigmask;
1835 }
1836
1837 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]);
1838 if (!SIGISMEMBER(ps->ps_signodefer, sig))
1839 SIGADDSET(lp->lwp_sigmask, sig);
1840
1841 crit_exit();
1842 lp->lwp_ru.ru_nsignals++;
1843 if (lp->lwp_sig != sig) {
1844 code = 0;
1845 } else {
1846 code = lp->lwp_code;
1847 lp->lwp_code = 0;
1848 lp->lwp_sig = 0;
1849 }
1850 (*p->p_sysent->sv_sendsig)(action, sig, &returnmask, code);
1851 }
1852 done:
1853 ;
1854 }
1855
1856 /*
1857 * Kill the current process for stated reason.
1858 */
1859 void
1860 killproc(struct proc *p, char *why)
1861 {
1862 log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n",
1863 p->p_pid, p->p_comm,
1864 p->p_ucred ? p->p_ucred->cr_uid : -1, why);
1865 ksignal(p, SIGKILL);
1866 }
1867
1868 /*
1869 * Force the current process to exit with the specified signal, dumping core
1870 * if appropriate. We bypass the normal tests for masked and caught signals,
1871 * allowing unrecoverable failures to terminate the process without changing
1872 * signal state. Mark the accounting record with the signal termination.
1873 * If dumping core, save the signal number for the debugger. Calls exit and
1874 * does not return.
1875 */
1876 void
1877 sigexit(struct proc *p, int sig)
1878 {
1879 struct lwp *lp = FIRST_LWP_IN_PROC(p); /* XXX lwp */
1880
1881 p->p_acflag |= AXSIG;
1882 if (sigprop(sig) & SA_CORE) {
1883 lp->lwp_sig = sig;
1884 /*
1885 * Log signals which would cause core dumps
1886 * (Log as LOG_INFO to appease those who don't want
1887 * these messages.)
1888 * XXX : Todo, as well as euid, write out ruid too
1889 */
1890 if (coredump(lp, sig) == 0)
1891 sig |= WCOREFLAG;
1892 if (kern_logsigexit)
1893 log(LOG_INFO,
1894 "pid %d (%s), uid %d: exited on signal %d%s\n",
1895 p->p_pid, p->p_comm,
1896 p->p_ucred ? p->p_ucred->cr_uid : -1,
1897 sig &~ WCOREFLAG,
1898 sig & WCOREFLAG ? " (core dumped)" : "");
1899 }
1900 exit1(W_EXITCODE(0, sig));
1901 /* NOTREACHED */
1902 }
1903
1904 static char corefilename[MAXPATHLEN+1] = {"%N.core"};
1905 SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename,
1906 sizeof(corefilename), "process corefile name format string");
1907
1908 /*
1909 * expand_name(name, uid, pid)
1910 * Expand the name described in corefilename, using name, uid, and pid.
1911 * corefilename is a kprintf-like string, with three format specifiers:
1912 * %N name of process ("name")
1913 * %P process id (pid)
1914 * %U user id (uid)
1915 * For example, "%N.core" is the default; they can be disabled completely
1916 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P".
1917 * This is controlled by the sysctl variable kern.corefile (see above).
1918 */
1919
1920 static char *
1921 expand_name(const char *name, uid_t uid, pid_t pid)
1922 {
1923 char *temp;
1924 char buf[11]; /* Buffer for pid/uid -- max 4B */
1925 int i, n;
1926 char *format = corefilename;
1927 size_t namelen;
1928
1929 temp = kmalloc(MAXPATHLEN + 1, M_TEMP, M_NOWAIT);
1930 if (temp == NULL)
1931 return NULL;
1932 namelen = strlen(name);
1933 for (i = 0, n = 0; n < MAXPATHLEN && format[i]; i++) {
1934 int l;
1935 switch (format[i]) {
1936 case '%': /* Format character */
1937 i++;
1938 switch (format[i]) {
1939 case '%':
1940 temp[n++] = '%';
1941 break;
1942 case 'N': /* process name */
1943 if ((n + namelen) > MAXPATHLEN) {
1944 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n",
1945 pid, name, uid, temp, name);
1946 kfree(temp, M_TEMP);
1947 return NULL;
1948 }
1949 memcpy(temp+n, name, namelen);
1950 n += namelen;
1951 break;
1952 case 'P': /* process id */
1953 l = ksprintf(buf, "%u", pid);
1954 if ((n + l) > MAXPATHLEN) {
1955 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n",
1956 pid, name, uid, temp, name);
1957 kfree(temp, M_TEMP);
1958 return NULL;
1959 }
1960 memcpy(temp+n, buf, l);
1961 n += l;
1962 break;
1963 case 'U': /* user id */
1964 l = ksprintf(buf, "%u", uid);
1965 if ((n + l) > MAXPATHLEN) {
1966 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n",
1967 pid, name, uid, temp, name);
1968 kfree(temp, M_TEMP);
1969 return NULL;
1970 }
1971 memcpy(temp+n, buf, l);
1972 n += l;
1973 break;
1974 default:
1975 log(LOG_ERR, "Unknown format character %c in `%s'\n", format[i], format);
1976 }
1977 break;
1978 default:
1979 temp[n++] = format[i];
1980 }
1981 }
1982 temp[n] = '\0';
1983 return temp;
1984 }
1985
1986 /*
1987 * Dump a process' core. The main routine does some
1988 * policy checking, and creates the name of the coredump;
1989 * then it passes on a vnode and a size limit to the process-specific
1990 * coredump routine if there is one; if there _is not_ one, it returns
1991 * ENOSYS; otherwise it returns the error from the process-specific routine.
1992 *
1993 * The parameter `lp' is the lwp which triggered the coredump.
1994 */
1995
1996 static int
1997 coredump(struct lwp *lp, int sig)
1998 {
1999 struct proc *p = lp->lwp_proc;
2000 struct vnode *vp;
2001 struct ucred *cred = p->p_ucred;
2002 struct flock lf;
2003 struct nlookupdata nd;
2004 struct vattr vattr;
2005 int error, error1;
2006 char *name; /* name of corefile */
2007 off_t limit;
2008
2009 STOPEVENT(p, S_CORE, 0);
2010
2011 if (((sugid_coredump == 0) && p->p_flag & P_SUGID) || do_coredump == 0)
2012 return (EFAULT);
2013
2014 /*
2015 * Note that the bulk of limit checking is done after
2016 * the corefile is created. The exception is if the limit
2017 * for corefiles is 0, in which case we don't bother
2018 * creating the corefile at all. This layout means that
2019 * a corefile is truncated instead of not being created,
2020 * if it is larger than the limit.
2021 */
2022 limit = p->p_rlimit[RLIMIT_CORE].rlim_cur;
2023 if (limit == 0)
2024 return EFBIG;
2025
2026 name = expand_name(p->p_comm, p->p_ucred->cr_uid, p->p_pid);
2027 if (name == NULL)
2028 return (EINVAL);
2029 error = nlookup_init(&nd, name, UIO_SYSSPACE, NLC_LOCKVP);
2030 if (error == 0)
2031 error = vn_open(&nd, NULL, O_CREAT | FWRITE | O_NOFOLLOW, S_IRUSR | S_IWUSR);
2032 kfree(name, M_TEMP);
2033 if (error) {
2034 nlookup_done(&nd);
2035 return (error);
2036 }
2037 vp = nd.nl_open_vp;
2038 nd.nl_open_vp = NULL;
2039 nlookup_done(&nd);
2040
2041 vn_unlock(vp);
2042 lf.l_whence = SEEK_SET;
2043 lf.l_start = 0;
2044 lf.l_len = 0;
2045 lf.l_type = F_WRLCK;
2046 error = VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, 0);
2047 if (error)
2048 goto out2;
2049
2050 /* Don't dump to non-regular files or files with links. */
2051 if (vp->v_type != VREG ||
2052 VOP_GETATTR(vp, &vattr) || vattr.va_nlink != 1) {
2053 error = EFAULT;
2054 goto out1;
2055 }
2056
2057 VATTR_NULL(&vattr);
2058 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
2059 vattr.va_size = 0;
2060 VOP_SETATTR(vp, &vattr, cred);
2061 p->p_acflag |= ACORE;
2062 vn_unlock(vp);
2063
2064 error = p->p_sysent->sv_coredump ?
2065 p->p_sysent->sv_coredump(lp, sig, vp, limit) : ENOSYS;
2066
2067 out1:
2068 lf.l_type = F_UNLCK;
2069 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, 0);
2070 out2:
2071 error1 = vn_close(vp, FWRITE);
2072 if (error == 0)
2073 error = error1;
2074 return (error);
2075 }
2076
2077 /*
2078 * Nonexistent system call-- signal process (may want to handle it).
2079 * Flag error in case process won't see signal immediately (blocked or ignored).
2080 */
2081 /* ARGSUSED */
2082 int
2083 sys_nosys(struct nosys_args *args)
2084 {
2085 lwpsignal(curproc, curthread->td_lwp, SIGSYS);
2086 return (EINVAL);
2087 }
2088
2089 /*
2090 * Send a SIGIO or SIGURG signal to a process or process group using
2091 * stored credentials rather than those of the current process.
2092 */
2093 void
2094 pgsigio(struct sigio *sigio, int sig, int checkctty)
2095 {
2096 if (sigio == NULL)
2097 return;
2098
2099 if (sigio->sio_pgid > 0) {
2100 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred,
2101 sigio->sio_proc))
2102 ksignal(sigio->sio_proc, sig);
2103 } else if (sigio->sio_pgid < 0) {
2104 struct proc *p;
2105
2106 lockmgr(&sigio->sio_pgrp->pg_lock, LK_EXCLUSIVE);
2107 LIST_FOREACH(p, &sigio->sio_pgrp->pg_members, p_pglist) {
2108 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, p) &&
2109 (checkctty == 0 || (p->p_flag & P_CONTROLT)))
2110 ksignal(p, sig);
2111 }
2112 lockmgr(&sigio->sio_pgrp->pg_lock, LK_RELEASE);
2113 }
2114 }
2115
2116 static int
2117 filt_sigattach(struct knote *kn)
2118 {
2119 struct proc *p = curproc;
2120
2121 kn->kn_ptr.p_proc = p;
2122 kn->kn_flags |= EV_CLEAR; /* automatically set */
2123
2124 /* XXX lock the proc here while adding to the list? */
2125 SLIST_INSERT_HEAD(&p->p_klist, kn, kn_selnext);
2126
2127 return (0);
2128 }
2129
2130 static void
2131 filt_sigdetach(struct knote *kn)
2132 {
2133 struct proc *p = kn->kn_ptr.p_proc;
2134
2135 SLIST_REMOVE(&p->p_klist, kn, knote, kn_selnext);
2136 }
2137
2138 /*
2139 * signal knotes are shared with proc knotes, so we apply a mask to
2140 * the hint in order to differentiate them from process hints. This
2141 * could be avoided by using a signal-specific knote list, but probably
2142 * isn't worth the trouble.
2143 */
2144 static int
2145 filt_signal(struct knote *kn, long hint)
2146 {
2147 if (hint & NOTE_SIGNAL) {
2148 hint &= ~NOTE_SIGNAL;
2149
2150 if (kn->kn_id == hint)
2151 kn->kn_data++;
2152 }
2153 return (kn->kn_data != 0);
2154 }
DragonFly vkernel multiprocessor port