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iscontrol(8): Fix synopsis, sync usage() & improve markup
[dragonfly.git] / sys / kern / kern_sig.c
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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 1.90 2008/06/09 04:33:08 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 if ((u_int)sig > _SIG_MAXSIG)
704 return (EINVAL);
705 if (pid > 0) {
706 struct proc *p;
707 struct lwp *lp = NULL;
708
709 /* kill single process */
710 if ((p = pfind(pid)) == NULL)
711 return (ESRCH);
712 if (!CANSIGNAL(p, sig))
713 return (EPERM);
714
715 /*
716 * NOP if the process is exiting. Note that lwpsignal() is
717 * called directly with P_WEXIT set to kill individual LWPs
718 * during exit, which is allowed.
719 */
720 if (p->p_flag & P_WEXIT)
721 return (0);
722 if (tid != -1) {
723 lp = lwp_rb_tree_RB_LOOKUP(&p->p_lwp_tree, tid);
724 if (lp == NULL)
725 return (ESRCH);
726 }
727 if (sig)
728 lwpsignal(p, lp, sig);
729 return (0);
730 }
731 /*
732 * If we come here, pid is a special broadcast pid.
733 * This doesn't mix with a tid.
734 */
735 if (tid != -1)
736 return (EINVAL);
737 switch (pid) {
738 case -1: /* broadcast signal */
739 return (dokillpg(sig, 0, 1));
740 case 0: /* signal own process group */
741 return (dokillpg(sig, 0, 0));
742 default: /* negative explicit process group */
743 return (dokillpg(sig, -pid, 0));
744 }
745 /* NOTREACHED */
746 }
747
748 int
749 sys_kill(struct kill_args *uap)
750 {
751 int error;
752
753 error = kern_kill(uap->signum, uap->pid, -1);
754 return (error);
755 }
756
757 int
758 sys_lwp_kill(struct lwp_kill_args *uap)
759 {
760 int error;
761 pid_t pid = uap->pid;
762
763 /*
764 * A tid is mandatory for lwp_kill(), otherwise
765 * you could simply use kill().
766 */
767 if (uap->tid == -1)
768 return (EINVAL);
769
770 /*
771 * To save on a getpid() function call for intra-process
772 * signals, pid == -1 means current process.
773 */
774 if (pid == -1)
775 pid = curproc->p_pid;
776
777 error = kern_kill(uap->signum, pid, uap->tid);
778 return (error);
779 }
780
781 /*
782 * Send a signal to a process group.
783 */
784 void
785 gsignal(int pgid, int sig)
786 {
787 struct pgrp *pgrp;
788
789 if (pgid && (pgrp = pgfind(pgid)))
790 pgsignal(pgrp, sig, 0);
791 }
792
793 /*
794 * Send a signal to a process group. If checktty is 1,
795 * limit to members which have a controlling terminal.
796 *
797 * pg_lock interlocks against a fork that might be in progress, to
798 * ensure that the new child process picks up the signal.
799 */
800 void
801 pgsignal(struct pgrp *pgrp, int sig, int checkctty)
802 {
803 struct proc *p;
804
805 if (pgrp) {
806 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE);
807 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
808 if (checkctty == 0 || p->p_flag & P_CONTROLT)
809 ksignal(p, sig);
810 }
811 lockmgr(&pgrp->pg_lock, LK_RELEASE);
812 }
813 }
814
815 /*
816 * Send a signal caused by a trap to the current lwp. If it will be caught
817 * immediately, deliver it with correct code. Otherwise, post it normally.
818 *
819 * These signals may ONLY be delivered to the specified lwp and may never
820 * be delivered to the process generically.
821 */
822 void
823 trapsignal(struct lwp *lp, int sig, u_long code)
824 {
825 struct proc *p = lp->lwp_proc;
826 struct sigacts *ps = p->p_sigacts;
827
828 /*
829 * If we are a virtual kernel running an emulated user process
830 * context, switch back to the virtual kernel context before
831 * trying to post the signal.
832 */
833 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) {
834 struct trapframe *tf = lp->lwp_md.md_regs;
835 tf->tf_trapno = 0;
836 vkernel_trap(lp, tf);
837 }
838
839
840 if ((p->p_flag & P_TRACED) == 0 && SIGISMEMBER(p->p_sigcatch, sig) &&
841 !SIGISMEMBER(lp->lwp_sigmask, sig)) {
842 lp->lwp_ru.ru_nsignals++;
843 #ifdef KTRACE
844 if (KTRPOINT(lp->lwp_thread, KTR_PSIG))
845 ktrpsig(lp, sig, ps->ps_sigact[_SIG_IDX(sig)],
846 &lp->lwp_sigmask, code);
847 #endif
848 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)], sig,
849 &lp->lwp_sigmask, code);
850 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]);
851 if (!SIGISMEMBER(ps->ps_signodefer, sig))
852 SIGADDSET(lp->lwp_sigmask, sig);
853 if (SIGISMEMBER(ps->ps_sigreset, sig)) {
854 /*
855 * See kern_sigaction() for origin of this code.
856 */
857 SIGDELSET(p->p_sigcatch, sig);
858 if (sig != SIGCONT &&
859 sigprop(sig) & SA_IGNORE)
860 SIGADDSET(p->p_sigignore, sig);
861 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
862 }
863 } else {
864 lp->lwp_code = code; /* XXX for core dump/debugger */
865 lp->lwp_sig = sig; /* XXX to verify code */
866 lwpsignal(p, lp, sig);
867 }
868 }
869
870 /*
871 * Find a suitable lwp to deliver the signal to.
872 *
873 * Returns NULL if all lwps hold the signal blocked.
874 */
875 static struct lwp *
876 find_lwp_for_signal(struct proc *p, int sig)
877 {
878 struct lwp *lp;
879 struct lwp *run, *sleep, *stop;
880
881 /*
882 * If the running/preempted thread belongs to the proc to which
883 * the signal is being delivered and this thread does not block
884 * the signal, then we can avoid a context switch by delivering
885 * the signal to this thread, because it will return to userland
886 * soon anyways.
887 */
888 lp = lwkt_preempted_proc();
889 if (lp != NULL && lp->lwp_proc == p && !SIGISMEMBER(lp->lwp_sigmask, sig))
890 return (lp);
891
892 run = sleep = stop = NULL;
893 FOREACH_LWP_IN_PROC(lp, p) {
894 /*
895 * If the signal is being blocked by the lwp, then this
896 * lwp is not eligible for receiving the signal.
897 */
898 if (SIGISMEMBER(lp->lwp_sigmask, sig))
899 continue;
900
901 switch (lp->lwp_stat) {
902 case LSRUN:
903 run = lp;
904 break;
905
906 case LSSTOP:
907 stop = lp;
908 break;
909
910 case LSSLEEP:
911 if (lp->lwp_flag & LWP_SINTR)
912 sleep = lp;
913 break;
914 }
915 }
916
917 if (run != NULL)
918 return (run);
919 else if (sleep != NULL)
920 return (sleep);
921 else
922 return (stop);
923 }
924
925 /*
926 * Send the signal to the process. If the signal has an action, the action
927 * is usually performed by the target process rather than the caller; we add
928 * the signal to the set of pending signals for the process.
929 *
930 * Exceptions:
931 * o When a stop signal is sent to a sleeping process that takes the
932 * default action, the process is stopped without awakening it.
933 * o SIGCONT restarts stopped processes (or puts them back to sleep)
934 * regardless of the signal action (eg, blocked or ignored).
935 *
936 * Other ignored signals are discarded immediately.
937 */
938 void
939 ksignal(struct proc *p, int sig)
940 {
941 lwpsignal(p, NULL, sig);
942 }
943
944 /*
945 * The core for ksignal. lp may be NULL, then a suitable thread
946 * will be chosen. If not, lp MUST be a member of p.
947 */
948 void
949 lwpsignal(struct proc *p, struct lwp *lp, int sig)
950 {
951 int prop;
952 sig_t action;
953
954 if (sig > _SIG_MAXSIG || sig <= 0) {
955 kprintf("lwpsignal: signal %d\n", sig);
956 panic("lwpsignal signal number");
957 }
958
959 KKASSERT(lp == NULL || lp->lwp_proc == p);
960
961 crit_enter();
962 KNOTE(&p->p_klist, NOTE_SIGNAL | sig);
963 crit_exit();
964
965 prop = sigprop(sig);
966
967 /*
968 * If proc is traced, always give parent a chance;
969 * if signal event is tracked by procfs, give *that*
970 * a chance, as well.
971 */
972 if ((p->p_flag & P_TRACED) || (p->p_stops & S_SIG)) {
973 action = SIG_DFL;
974 } else {
975 /*
976 * Do not try to deliver signals to an exiting lwp. Note
977 * that we must still deliver the signal if P_WEXIT is set
978 * in the process flags.
979 */
980 if (lp && (lp->lwp_flag & LWP_WEXIT))
981 return;
982
983 /*
984 * If the signal is being ignored, then we forget about
985 * it immediately. NOTE: We don't set SIGCONT in p_sigignore,
986 * and if it is set to SIG_IGN, action will be SIG_DFL here.
987 */
988 if (SIGISMEMBER(p->p_sigignore, sig))
989 return;
990 if (SIGISMEMBER(p->p_sigcatch, sig))
991 action = SIG_CATCH;
992 else
993 action = SIG_DFL;
994 }
995
996 /*
997 * If continuing, clear any pending STOP signals.
998 */
999 if (prop & SA_CONT)
1000 SIG_STOPSIGMASK(p->p_siglist);
1001
1002 if (prop & SA_STOP) {
1003 /*
1004 * If sending a tty stop signal to a member of an orphaned
1005 * process group, discard the signal here if the action
1006 * is default; don't stop the process below if sleeping,
1007 * and don't clear any pending SIGCONT.
1008 */
1009 if (prop & SA_TTYSTOP && p->p_pgrp->pg_jobc == 0 &&
1010 action == SIG_DFL) {
1011 return;
1012 }
1013 SIG_CONTSIGMASK(p->p_siglist);
1014 p->p_flag &= ~P_CONTINUED;
1015 }
1016
1017 crit_enter();
1018
1019 if (p->p_stat == SSTOP) {
1020 /*
1021 * Nobody can handle this signal, add it to the lwp or
1022 * process pending list
1023 */
1024 if (lp)
1025 SIGADDSET(lp->lwp_siglist, sig);
1026 else
1027 SIGADDSET(p->p_siglist, sig);
1028
1029 /*
1030 * If the process is stopped and is being traced, then no
1031 * further action is necessary.
1032 */
1033 if (p->p_flag & P_TRACED)
1034 goto out;
1035
1036 /*
1037 * If the process is stopped and receives a KILL signal,
1038 * make the process runnable.
1039 */
1040 if (sig == SIGKILL) {
1041 proc_unstop(p);
1042 goto active_process;
1043 }
1044
1045 /*
1046 * If the process is stopped and receives a CONT signal,
1047 * then try to make the process runnable again.
1048 */
1049 if (prop & SA_CONT) {
1050 /*
1051 * If SIGCONT is default (or ignored), we continue the
1052 * process but don't leave the signal in p_siglist, as
1053 * it has no further action. If SIGCONT is held, we
1054 * continue the process and leave the signal in
1055 * p_siglist. If the process catches SIGCONT, let it
1056 * handle the signal itself.
1057 */
1058 /* XXX what if the signal is being held blocked? */
1059 p->p_flag |= P_CONTINUED;
1060 wakeup(p->p_pptr);
1061 if (action == SIG_DFL)
1062 SIGDELSET(p->p_siglist, sig);
1063 proc_unstop(p);
1064 if (action == SIG_CATCH)
1065 goto active_process;
1066 goto out;
1067 }
1068
1069 /*
1070 * If the process is stopped and receives another STOP
1071 * signal, we do not need to stop it again. If we did
1072 * the shell could get confused.
1073 *
1074 * However, if the current/preempted lwp is part of the
1075 * process receiving the signal, we need to keep it,
1076 * so that this lwp can stop in issignal() later, as
1077 * we don't want to wait until it reaches userret!
1078 */
1079 if (prop & SA_STOP) {
1080 if (lwkt_preempted_proc() == NULL ||
1081 lwkt_preempted_proc()->lwp_proc != p)
1082 SIGDELSET(p->p_siglist, sig);
1083 }
1084
1085 /*
1086 * Otherwise the process is stopped and it received some
1087 * signal, which does not change its stopped state.
1088 *
1089 * We have to select one thread to set LWP_BREAKTSLEEP,
1090 * so that the current signal will break the sleep
1091 * as soon as a SA_CONT signal will unstop the process.
1092 */
1093 if (lp == NULL)
1094 lp = find_lwp_for_signal(p, sig);
1095 if (lp != NULL &&
1096 (lp->lwp_stat == LSSLEEP || lp->lwp_stat == LSSTOP))
1097 lp->lwp_flag |= LWP_BREAKTSLEEP;
1098 goto out;
1099
1100 /* NOTREACHED */
1101 }
1102 /* else not stopped */
1103 active_process:
1104
1105 /*
1106 * Never deliver a lwp-specific signal to a random lwp.
1107 */
1108 if (lp == NULL) {
1109 lp = find_lwp_for_signal(p, sig);
1110 if (lp && SIGISMEMBER(lp->lwp_sigmask, sig))
1111 lp = NULL;
1112 }
1113
1114 /*
1115 * Deliver to the process generically if (1) the signal is being
1116 * sent to any thread or (2) we could not find a thread to deliver
1117 * it to.
1118 */
1119 if (lp == NULL) {
1120 SIGADDSET(p->p_siglist, sig);
1121 goto out;
1122 }
1123
1124 /*
1125 * Deliver to a specific LWP whether it masks it or not. It will
1126 * not be dispatched if masked but we must still deliver it.
1127 */
1128 if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) &&
1129 (p->p_flag & P_TRACED) == 0) {
1130 p->p_nice = NZERO;
1131 }
1132
1133 /*
1134 * If the process receives a STOP signal which indeed needs to
1135 * stop the process, do so. If the process chose to catch the
1136 * signal, it will be treated like any other signal.
1137 */
1138 if ((prop & SA_STOP) && action == SIG_DFL) {
1139 /*
1140 * If a child holding parent blocked, stopping
1141 * could cause deadlock. Take no action at this
1142 * time.
1143 */
1144 if (p->p_flag & P_PPWAIT) {
1145 SIGADDSET(p->p_siglist, sig);
1146 goto out;
1147 }
1148
1149 /*
1150 * Do not actually try to manipulate the process, but simply
1151 * stop it. Lwps will stop as soon as they safely can.
1152 */
1153 p->p_xstat = sig;
1154 proc_stop(p);
1155 goto out;
1156 }
1157
1158 /*
1159 * If it is a CONT signal with default action, just ignore it.
1160 */
1161 if ((prop & SA_CONT) && action == SIG_DFL)
1162 goto out;
1163
1164 /*
1165 * Mark signal pending at this specific thread.
1166 */
1167 SIGADDSET(lp->lwp_siglist, sig);
1168
1169 lwp_signotify(lp);
1170
1171 out:
1172 crit_exit();
1173 }
1174
1175 void
1176 lwp_signotify(struct lwp *lp)
1177 {
1178 crit_enter();
1179 if (lp->lwp_stat == LSSLEEP || lp->lwp_stat == LSSTOP) {
1180 /*
1181 * Thread is in tsleep.
1182 */
1183
1184 /*
1185 * If the thread is sleeping uninterruptibly
1186 * we can't interrupt the sleep... the signal will
1187 * be noticed when the lwp returns through
1188 * trap() or syscall().
1189 *
1190 * Otherwise the signal can interrupt the sleep.
1191 *
1192 * If the process is traced, the lwp will handle the
1193 * tracing in issignal() when it returns to userland.
1194 */
1195 if (lp->lwp_flag & LWP_SINTR) {
1196 /*
1197 * Make runnable and break out of any tsleep as well.
1198 */
1199 lp->lwp_flag |= LWP_BREAKTSLEEP;
1200 setrunnable(lp);
1201 }
1202 } else {
1203 /*
1204 * Otherwise the thread is running
1205 *
1206 * LSRUN does nothing with the signal, other than kicking
1207 * ourselves if we are running.
1208 * SZOMB and SIDL mean that it will either never be noticed,
1209 * or noticed very soon.
1210 *
1211 * Note that lwp_thread may be NULL or may not be completely
1212 * initialized if the process is in the SIDL or SZOMB state.
1213 *
1214 * For SMP we may have to forward the request to another cpu.
1215 * YYY the MP lock prevents the target process from moving
1216 * to another cpu, see kern/kern_switch.c
1217 *
1218 * If the target thread is waiting on its message port,
1219 * wakeup the target thread so it can check (or ignore)
1220 * the new signal. YYY needs cleanup.
1221 */
1222 if (lp == lwkt_preempted_proc()) {
1223 signotify();
1224 } else if (lp->lwp_stat == LSRUN) {
1225 struct thread *td = lp->lwp_thread;
1226 struct proc *p = lp->lwp_proc;
1227
1228 KASSERT(td != NULL,
1229 ("pid %d/%d NULL lwp_thread stat %d flags %08x/%08x",
1230 p->p_pid, lp->lwp_tid, lp->lwp_stat,
1231 p->p_flag, lp->lwp_flag));
1232
1233 /*
1234 * To prevent a MP race with TDF_SINTR we must
1235 * schedule the thread on the correct cpu.
1236 */
1237 #ifdef SMP
1238 if (td->td_gd != mycpu) {
1239 LWPHOLD(lp);
1240 lwkt_send_ipiq(td->td_gd, signotify_remote, lp);
1241 } else
1242 #endif
1243 if (td->td_flags & TDF_SINTR)
1244 lwkt_schedule(td);
1245 }
1246 }
1247 crit_exit();
1248 }
1249
1250 #ifdef SMP
1251
1252 /*
1253 * This function is called via an IPI. We will be in a critical section but
1254 * the MP lock will NOT be held. Also note that by the time the ipi message
1255 * gets to us the process 'p' (arg) may no longer be scheduled or even valid.
1256 */
1257 static void
1258 signotify_remote(void *arg)
1259 {
1260 struct lwp *lp = arg;
1261
1262 if (lp == lwkt_preempted_proc()) {
1263 signotify();
1264 } else {
1265 struct thread *td = lp->lwp_thread;
1266 if (td->td_flags & TDF_SINTR)
1267 lwkt_schedule(td);
1268 }
1269 LWPRELE(lp);
1270 }
1271
1272 #endif
1273
1274 void
1275 proc_stop(struct proc *p)
1276 {
1277 struct lwp *lp;
1278
1279 /* If somebody raced us, be happy with it */
1280 if (p->p_stat == SSTOP || p->p_stat == SZOMB)
1281 return;
1282
1283 crit_enter();
1284 p->p_stat = SSTOP;
1285
1286 FOREACH_LWP_IN_PROC(lp, p) {
1287 switch (lp->lwp_stat) {
1288 case LSSTOP:
1289 /*
1290 * Do nothing, we are already counted in
1291 * p_nstopped.
1292 */
1293 break;
1294
1295 case LSSLEEP:
1296 /*
1297 * We're sleeping, but we will stop before
1298 * returning to userspace, so count us
1299 * as stopped as well. We set LWP_WSTOP
1300 * to signal the lwp that it should not
1301 * increase p_nstopped when reaching tstop().
1302 */
1303 if ((lp->lwp_flag & LWP_WSTOP) == 0) {
1304 lp->lwp_flag |= LWP_WSTOP;
1305 ++p->p_nstopped;
1306 }
1307 break;
1308
1309 case LSRUN:
1310 /*
1311 * We might notify ourself, but that's not
1312 * a problem.
1313 */
1314 lwp_signotify(lp);
1315 break;
1316 }
1317 }
1318
1319 if (p->p_nstopped == p->p_nthreads) {
1320 p->p_flag &= ~P_WAITED;
1321 wakeup(p->p_pptr);
1322 if ((p->p_pptr->p_sigacts->ps_flag & PS_NOCLDSTOP) == 0)
1323 ksignal(p->p_pptr, SIGCHLD);
1324 }
1325 crit_exit();
1326 }
1327
1328 void
1329 proc_unstop(struct proc *p)
1330 {
1331 struct lwp *lp;
1332
1333 if (p->p_stat != SSTOP)
1334 return;
1335
1336 crit_enter();
1337 p->p_stat = SACTIVE;
1338
1339 FOREACH_LWP_IN_PROC(lp, p) {
1340 switch (lp->lwp_stat) {
1341 case LSRUN:
1342 /*
1343 * Uh? Not stopped? Well, I guess that's okay.
1344 */
1345 if (bootverbose)
1346 kprintf("proc_unstop: lwp %d/%d not sleeping\n",
1347 p->p_pid, lp->lwp_tid);
1348 break;
1349
1350 case LSSLEEP:
1351 /*
1352 * Still sleeping. Don't bother waking it up.
1353 * However, if this thread was counted as
1354 * stopped, undo this.
1355 *
1356 * Nevertheless we call setrunnable() so that it
1357 * will wake up in case a signal or timeout arrived
1358 * in the meantime.
1359 */
1360 if (lp->lwp_flag & LWP_WSTOP) {
1361 lp->lwp_flag &= ~LWP_WSTOP;
1362 --p->p_nstopped;
1363 } else {
1364 if (bootverbose)
1365 kprintf("proc_unstop: lwp %d/%d sleeping, not stopped\n",
1366 p->p_pid, lp->lwp_tid);
1367 }
1368 /* FALLTHROUGH */
1369
1370 case LSSTOP:
1371 setrunnable(lp);
1372 break;
1373
1374 }
1375 }
1376 crit_exit();
1377 }
1378
1379 static int
1380 kern_sigtimedwait(sigset_t waitset, siginfo_t *info, struct timespec *timeout)
1381 {
1382 sigset_t savedmask, set;
1383 struct proc *p = curproc;
1384 struct lwp *lp = curthread->td_lwp;
1385 int error, sig, hz, timevalid = 0;
1386 struct timespec rts, ets, ts;
1387 struct timeval tv;
1388
1389 error = 0;
1390 sig = 0;
1391 ets.tv_sec = 0; /* silence compiler warning */
1392 ets.tv_nsec = 0; /* silence compiler warning */
1393 SIG_CANTMASK(waitset);
1394 savedmask = lp->lwp_sigmask;
1395
1396 if (timeout) {
1397 if (timeout->tv_sec >= 0 && timeout->tv_nsec >= 0 &&
1398 timeout->tv_nsec < 1000000000) {
1399 timevalid = 1;
1400 getnanouptime(&rts);
1401 ets = rts;
1402 timespecadd(&ets, timeout);
1403 }
1404 }
1405
1406 for (;;) {
1407 set = lwp_sigpend(lp);
1408 SIGSETAND(set, waitset);
1409 if ((sig = sig_ffs(&set)) != 0) {
1410 SIGFILLSET(lp->lwp_sigmask);
1411 SIGDELSET(lp->lwp_sigmask, sig);
1412 SIG_CANTMASK(lp->lwp_sigmask);
1413 sig = issignal(lp, 1);
1414 /*
1415 * It may be a STOP signal, in the case, issignal
1416 * returns 0, because we may stop there, and new
1417 * signal can come in, we should restart if we got
1418 * nothing.
1419 */
1420 if (sig == 0)
1421 continue;
1422 else
1423 break;
1424 }
1425
1426 /*
1427 * Previous checking got nothing, and we retried but still
1428 * got nothing, we should return the error status.
1429 */
1430 if (error)
1431 break;
1432
1433 /*
1434 * POSIX says this must be checked after looking for pending
1435 * signals.
1436 */
1437 if (timeout) {
1438 if (timevalid == 0) {
1439 error = EINVAL;
1440 break;
1441 }
1442 getnanouptime(&rts);
1443 if (timespeccmp(&rts, &ets, >=)) {
1444 error = EAGAIN;
1445 break;
1446 }
1447 ts = ets;
1448 timespecsub(&ts, &rts);
1449 TIMESPEC_TO_TIMEVAL(&tv, &ts);
1450 hz = tvtohz_high(&tv);
1451 } else
1452 hz = 0;
1453
1454 lp->lwp_sigmask = savedmask;
1455 SIGSETNAND(lp->lwp_sigmask, waitset);
1456 /*
1457 * We won't ever be woken up. Instead, our sleep will
1458 * be broken in lwpsignal().
1459 */
1460 error = tsleep(&p->p_sigacts, PCATCH, "sigwt", hz);
1461 if (timeout) {
1462 if (error == ERESTART) {
1463 /* can not restart a timeout wait. */
1464 error = EINTR;
1465 } else if (error == EAGAIN) {
1466 /* will calculate timeout by ourself. */
1467 error = 0;
1468 }
1469 }
1470 /* Retry ... */
1471 }
1472
1473 lp->lwp_sigmask = savedmask;
1474 if (sig) {
1475 error = 0;
1476 bzero(info, sizeof(*info));
1477 info->si_signo = sig;
1478 lwp_delsig(lp, sig); /* take the signal! */
1479
1480 if (sig == SIGKILL)
1481 sigexit(lp, sig);
1482 }
1483 return (error);
1484 }
1485
1486 int
1487 sys_sigtimedwait(struct sigtimedwait_args *uap)
1488 {
1489 struct timespec ts;
1490 struct timespec *timeout;
1491 sigset_t set;
1492 siginfo_t info;
1493 int error;
1494
1495 if (uap->timeout) {
1496 error = copyin(uap->timeout, &ts, sizeof(ts));
1497 if (error)
1498 return (error);
1499 timeout = &ts;
1500 } else {
1501 timeout = NULL;
1502 }
1503 error = copyin(uap->set, &set, sizeof(set));
1504 if (error)
1505 return (error);
1506 error = kern_sigtimedwait(set, &info, timeout);
1507 if (error)
1508 return (error);
1509 if (uap->info)
1510 error = copyout(&info, uap->info, sizeof(info));
1511 /* Repost if we got an error. */
1512 /*
1513 * XXX lwp
1514 *
1515 * This could transform a thread-specific signal to another
1516 * thread / process pending signal.
1517 */
1518 if (error)
1519 ksignal(curproc, info.si_signo);
1520 else
1521 uap->sysmsg_result = info.si_signo;
1522 return (error);
1523 }
1524
1525 int
1526 sys_sigwaitinfo(struct sigwaitinfo_args *uap)
1527 {
1528 siginfo_t info;
1529 sigset_t set;
1530 int error;
1531
1532 error = copyin(uap->set, &set, sizeof(set));
1533 if (error)
1534 return (error);
1535 error = kern_sigtimedwait(set, &info, NULL);
1536 if (error)
1537 return (error);
1538 if (uap->info)
1539 error = copyout(&info, uap->info, sizeof(info));
1540 /* Repost if we got an error. */
1541 /*
1542 * XXX lwp
1543 *
1544 * This could transform a thread-specific signal to another
1545 * thread / process pending signal.
1546 */
1547 if (error)
1548 ksignal(curproc, info.si_signo);
1549 else
1550 uap->sysmsg_result = info.si_signo;
1551 return (error);
1552 }
1553
1554 /*
1555 * If the current process has received a signal that would interrupt a
1556 * system call, return EINTR or ERESTART as appropriate.
1557 */
1558 int
1559 iscaught(struct lwp *lp)
1560 {
1561 struct proc *p = lp->lwp_proc;
1562 int sig;
1563
1564 if (p) {
1565 if ((sig = CURSIG(lp)) != 0) {
1566 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig))
1567 return (EINTR);
1568 return (ERESTART);
1569 }
1570 }
1571 return(EWOULDBLOCK);
1572 }
1573
1574 /*
1575 * If the current process has received a signal (should be caught or cause
1576 * termination, should interrupt current syscall), return the signal number.
1577 * Stop signals with default action are processed immediately, then cleared;
1578 * they aren't returned. This is checked after each entry to the system for
1579 * a syscall or trap (though this can usually be done without calling issignal
1580 * by checking the pending signal masks in the CURSIG macro.) The normal call
1581 * sequence is
1582 *
1583 * This routine is called via CURSIG/__cursig and the MP lock might not be
1584 * held. Obtain the MP lock for the duration of the operation.
1585 *
1586 * while (sig = CURSIG(curproc))
1587 * postsig(sig);
1588 */
1589 int
1590 issignal(struct lwp *lp, int maytrace)
1591 {
1592 struct proc *p = lp->lwp_proc;
1593 sigset_t mask;
1594 int sig, prop;
1595
1596 get_mplock();
1597 for (;;) {
1598 int traced = (p->p_flag & P_TRACED) || (p->p_stops & S_SIG);
1599
1600 /*
1601 * If this process is supposed to stop, stop this thread.
1602 */
1603 if (p->p_stat == SSTOP)
1604 tstop();
1605
1606 mask = lwp_sigpend(lp);
1607 SIGSETNAND(mask, lp->lwp_sigmask);
1608 if (p->p_flag & P_PPWAIT)
1609 SIG_STOPSIGMASK(mask);
1610 if (SIGISEMPTY(mask)) { /* no signal to send */
1611 rel_mplock();
1612 return (0);
1613 }
1614 sig = sig_ffs(&mask);
1615
1616 STOPEVENT(p, S_SIG, sig);
1617
1618 /*
1619 * We should see pending but ignored signals
1620 * only if P_TRACED was on when they were posted.
1621 */
1622 if (SIGISMEMBER(p->p_sigignore, sig) && (traced == 0)) {
1623 lwp_delsig(lp, sig);
1624 continue;
1625 }
1626 if (maytrace && (p->p_flag & P_TRACED) && (p->p_flag & P_PPWAIT) == 0) {
1627 /*
1628 * If traced, always stop, and stay stopped until
1629 * released by the parent.
1630 *
1631 * NOTE: SSTOP may get cleared during the loop,
1632 * but we do not re-notify the parent if we have
1633 * to loop several times waiting for the parent
1634 * to let us continue.
1635 *
1636 * XXX not sure if this is still true
1637 */
1638 p->p_xstat = sig;
1639 proc_stop(p);
1640 do {
1641 tstop();
1642 } while (!trace_req(p) && (p->p_flag & P_TRACED));
1643
1644 /*
1645 * If parent wants us to take the signal,
1646 * then it will leave it in p->p_xstat;
1647 * otherwise we just look for signals again.
1648 */
1649 lwp_delsig(lp, sig); /* clear old signal */
1650 sig = p->p_xstat;
1651 if (sig == 0)
1652 continue;
1653
1654 /*
1655 * Put the new signal into p_siglist. If the
1656 * signal is being masked, look for other signals.
1657 *
1658 * XXX lwp might need a call to ksignal()
1659 */
1660 SIGADDSET(p->p_siglist, sig);
1661 if (SIGISMEMBER(lp->lwp_sigmask, sig))
1662 continue;
1663
1664 /*
1665 * If the traced bit got turned off, go back up
1666 * to the top to rescan signals. This ensures
1667 * that p_sig* and ps_sigact are consistent.
1668 */
1669 if ((p->p_flag & P_TRACED) == 0)
1670 continue;
1671 }
1672
1673 prop = sigprop(sig);
1674
1675 /*
1676 * Decide whether the signal should be returned.
1677 * Return the signal's number, or fall through
1678 * to clear it from the pending mask.
1679 */
1680 switch ((intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) {
1681 case (intptr_t)SIG_DFL:
1682 /*
1683 * Don't take default actions on system processes.
1684 */
1685 if (p->p_pid <= 1) {
1686 #ifdef DIAGNOSTIC
1687 /*
1688 * Are you sure you want to ignore SIGSEGV
1689 * in init? XXX
1690 */
1691 kprintf("Process (pid %lu) got signal %d\n",
1692 (u_long)p->p_pid, sig);
1693 #endif
1694 break; /* == ignore */
1695 }
1696
1697 /*
1698 * Handle the in-kernel checkpoint action
1699 */
1700 if (prop & SA_CKPT) {
1701 checkpoint_signal_handler(lp);
1702 break;
1703 }
1704
1705 /*
1706 * If there is a pending stop signal to process
1707 * with default action, stop here,
1708 * then clear the signal. However,
1709 * if process is member of an orphaned
1710 * process group, ignore tty stop signals.
1711 */
1712 if (prop & SA_STOP) {
1713 if (p->p_flag & P_TRACED ||
1714 (p->p_pgrp->pg_jobc == 0 &&
1715 prop & SA_TTYSTOP))
1716 break; /* == ignore */
1717 p->p_xstat = sig;
1718 proc_stop(p);
1719 tstop();
1720 break;
1721 } else if (prop & SA_IGNORE) {
1722 /*
1723 * Except for SIGCONT, shouldn't get here.
1724 * Default action is to ignore; drop it.
1725 */
1726 break; /* == ignore */
1727 } else {
1728 rel_mplock();
1729 return (sig);
1730 }
1731
1732 /*NOTREACHED*/
1733
1734 case (intptr_t)SIG_IGN:
1735 /*
1736 * Masking above should prevent us ever trying
1737 * to take action on an ignored signal other
1738 * than SIGCONT, unless process is traced.
1739 */
1740 if ((prop & SA_CONT) == 0 &&
1741 (p->p_flag & P_TRACED) == 0)
1742 kprintf("issignal\n");
1743 break; /* == ignore */
1744
1745 default:
1746 /*
1747 * This signal has an action, let
1748 * postsig() process it.
1749 */
1750 rel_mplock();
1751 return (sig);
1752 }
1753 lwp_delsig(lp, sig); /* take the signal! */
1754 }
1755 /* NOTREACHED */
1756 }
1757
1758 /*
1759 * Take the action for the specified signal
1760 * from the current set of pending signals.
1761 */
1762 void
1763 postsig(int sig)
1764 {
1765 struct lwp *lp = curthread->td_lwp;
1766 struct proc *p = lp->lwp_proc;
1767 struct sigacts *ps = p->p_sigacts;
1768 sig_t action;
1769 sigset_t returnmask;
1770 int code;
1771
1772 KASSERT(sig != 0, ("postsig"));
1773
1774 /*
1775 * If we are a virtual kernel running an emulated user process
1776 * context, switch back to the virtual kernel context before
1777 * trying to post the signal.
1778 */
1779 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) {
1780 struct trapframe *tf = lp->lwp_md.md_regs;
1781 tf->tf_trapno = 0;
1782 vkernel_trap(lp, tf);
1783 }
1784
1785 lwp_delsig(lp, sig);
1786 action = ps->ps_sigact[_SIG_IDX(sig)];
1787 #ifdef KTRACE
1788 if (KTRPOINT(lp->lwp_thread, KTR_PSIG))
1789 ktrpsig(lp, sig, action, lp->lwp_flag & LWP_OLDMASK ?
1790 &lp->lwp_oldsigmask : &lp->lwp_sigmask, 0);
1791 #endif
1792 STOPEVENT(p, S_SIG, sig);
1793
1794 if (action == SIG_DFL) {
1795 /*
1796 * Default action, where the default is to kill
1797 * the process. (Other cases were ignored above.)
1798 */
1799 sigexit(lp, sig);
1800 /* NOTREACHED */
1801 } else {
1802 /*
1803 * If we get here, the signal must be caught.
1804 */
1805 KASSERT(action != SIG_IGN && !SIGISMEMBER(lp->lwp_sigmask, sig),
1806 ("postsig action"));
1807
1808 crit_enter();
1809
1810 /*
1811 * Reset the signal handler if asked to
1812 */
1813 if (SIGISMEMBER(ps->ps_sigreset, sig)) {
1814 /*
1815 * See kern_sigaction() for origin of this code.
1816 */
1817 SIGDELSET(p->p_sigcatch, sig);
1818 if (sig != SIGCONT &&
1819 sigprop(sig) & SA_IGNORE)
1820 SIGADDSET(p->p_sigignore, sig);
1821 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
1822 }
1823
1824 /*
1825 * Handle the mailbox case. Copyout to the appropriate
1826 * location but do not generate a signal frame. The system
1827 * call simply returns EINTR and the user is responsible for
1828 * polling the mailbox.
1829 */
1830 if (SIGISMEMBER(ps->ps_sigmailbox, sig)) {
1831 int sig_copy = sig;
1832 copyout(&sig_copy, (void *)action, sizeof(int));
1833 curproc->p_flag |= P_MAILBOX;
1834 crit_exit();
1835 goto done;
1836 }
1837
1838 /*
1839 * Set the signal mask and calculate the mask to restore
1840 * when the signal function returns.
1841 *
1842 * Special case: user has done a sigsuspend. Here the
1843 * current mask is not of interest, but rather the
1844 * mask from before the sigsuspend is what we want
1845 * restored after the signal processing is completed.
1846 */
1847 if (lp->lwp_flag & LWP_OLDMASK) {
1848 returnmask = lp->lwp_oldsigmask;
1849 lp->lwp_flag &= ~LWP_OLDMASK;
1850 } else {
1851 returnmask = lp->lwp_sigmask;
1852 }
1853
1854 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]);
1855 if (!SIGISMEMBER(ps->ps_signodefer, sig))
1856 SIGADDSET(lp->lwp_sigmask, sig);
1857
1858 crit_exit();
1859 lp->lwp_ru.ru_nsignals++;
1860 if (lp->lwp_sig != sig) {
1861 code = 0;
1862 } else {
1863 code = lp->lwp_code;
1864 lp->lwp_code = 0;
1865 lp->lwp_sig = 0;
1866 }
1867 (*p->p_sysent->sv_sendsig)(action, sig, &returnmask, code);
1868 }
1869 done:
1870 ;
1871 }
1872
1873 /*
1874 * Kill the current process for stated reason.
1875 */
1876 void
1877 killproc(struct proc *p, char *why)
1878 {
1879 log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n",
1880 p->p_pid, p->p_comm,
1881 p->p_ucred ? p->p_ucred->cr_uid : -1, why);
1882 ksignal(p, SIGKILL);
1883 }
1884
1885 /*
1886 * Force the current process to exit with the specified signal, dumping core
1887 * if appropriate. We bypass the normal tests for masked and caught signals,
1888 * allowing unrecoverable failures to terminate the process without changing
1889 * signal state. Mark the accounting record with the signal termination.
1890 * If dumping core, save the signal number for the debugger. Calls exit and
1891 * does not return.
1892 */
1893 void
1894 sigexit(struct lwp *lp, int sig)
1895 {
1896 struct proc *p = lp->lwp_proc;
1897
1898 p->p_acflag |= AXSIG;
1899 if (sigprop(sig) & SA_CORE) {
1900 lp->lwp_sig = sig;
1901 /*
1902 * Log signals which would cause core dumps
1903 * (Log as LOG_INFO to appease those who don't want
1904 * these messages.)
1905 * XXX : Todo, as well as euid, write out ruid too
1906 */
1907 if (coredump(lp, sig) == 0)
1908 sig |= WCOREFLAG;
1909 if (kern_logsigexit)
1910 log(LOG_INFO,
1911 "pid %d (%s), uid %d: exited on signal %d%s\n",
1912 p->p_pid, p->p_comm,
1913 p->p_ucred ? p->p_ucred->cr_uid : -1,
1914 sig &~ WCOREFLAG,
1915 sig & WCOREFLAG ? " (core dumped)" : "");
1916 }
1917 exit1(W_EXITCODE(0, sig));
1918 /* NOTREACHED */
1919 }
1920
1921 static char corefilename[MAXPATHLEN+1] = {"%N.core"};
1922 SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename,
1923 sizeof(corefilename), "process corefile name format string");
1924
1925 /*
1926 * expand_name(name, uid, pid)
1927 * Expand the name described in corefilename, using name, uid, and pid.
1928 * corefilename is a kprintf-like string, with three format specifiers:
1929 * %N name of process ("name")
1930 * %P process id (pid)
1931 * %U user id (uid)
1932 * For example, "%N.core" is the default; they can be disabled completely
1933 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P".
1934 * This is controlled by the sysctl variable kern.corefile (see above).
1935 */
1936
1937 static char *
1938 expand_name(const char *name, uid_t uid, pid_t pid)
1939 {
1940 char *temp;
1941 char buf[11]; /* Buffer for pid/uid -- max 4B */
1942 int i, n;
1943 char *format = corefilename;
1944 size_t namelen;
1945
1946 temp = kmalloc(MAXPATHLEN + 1, M_TEMP, M_NOWAIT);
1947 if (temp == NULL)
1948 return NULL;
1949 namelen = strlen(name);
1950 for (i = 0, n = 0; n < MAXPATHLEN && format[i]; i++) {
1951 int l;
1952 switch (format[i]) {
1953 case '%': /* Format character */
1954 i++;
1955 switch (format[i]) {
1956 case '%':
1957 temp[n++] = '%';
1958 break;
1959 case 'N': /* process name */
1960 if ((n + namelen) > MAXPATHLEN) {
1961 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n",
1962 pid, name, uid, temp, name);
1963 kfree(temp, M_TEMP);
1964 return NULL;
1965 }
1966 memcpy(temp+n, name, namelen);
1967 n += namelen;
1968 break;
1969 case 'P': /* process id */
1970 l = ksprintf(buf, "%u", pid);
1971 if ((n + l) > MAXPATHLEN) {
1972 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n",
1973 pid, name, uid, temp, name);
1974 kfree(temp, M_TEMP);
1975 return NULL;
1976 }
1977 memcpy(temp+n, buf, l);
1978 n += l;
1979 break;
1980 case 'U': /* user id */
1981 l = ksprintf(buf, "%u", uid);
1982 if ((n + l) > MAXPATHLEN) {
1983 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n",
1984 pid, name, uid, temp, name);
1985 kfree(temp, M_TEMP);
1986 return NULL;
1987 }
1988 memcpy(temp+n, buf, l);
1989 n += l;
1990 break;
1991 default:
1992 log(LOG_ERR, "Unknown format character %c in `%s'\n", format[i], format);
1993 }
1994 break;
1995 default:
1996 temp[n++] = format[i];
1997 }
1998 }
1999 temp[n] = '\0';
2000 return temp;
2001 }
2002
2003 /*
2004 * Dump a process' core. The main routine does some
2005 * policy checking, and creates the name of the coredump;
2006 * then it passes on a vnode and a size limit to the process-specific
2007 * coredump routine if there is one; if there _is not_ one, it returns
2008 * ENOSYS; otherwise it returns the error from the process-specific routine.
2009 *
2010 * The parameter `lp' is the lwp which triggered the coredump.
2011 */
2012
2013 static int
2014 coredump(struct lwp *lp, int sig)
2015 {
2016 struct proc *p = lp->lwp_proc;
2017 struct vnode *vp;
2018 struct ucred *cred = p->p_ucred;
2019 struct flock lf;
2020 struct nlookupdata nd;
2021 struct vattr vattr;
2022 int error, error1;
2023 char *name; /* name of corefile */
2024 off_t limit;
2025
2026 STOPEVENT(p, S_CORE, 0);
2027
2028 if (((sugid_coredump == 0) && p->p_flag & P_SUGID) || do_coredump == 0)
2029 return (EFAULT);
2030
2031 /*
2032 * Note that the bulk of limit checking is done after
2033 * the corefile is created. The exception is if the limit
2034 * for corefiles is 0, in which case we don't bother
2035 * creating the corefile at all. This layout means that
2036 * a corefile is truncated instead of not being created,
2037 * if it is larger than the limit.
2038 */
2039 limit = p->p_rlimit[RLIMIT_CORE].rlim_cur;
2040 if (limit == 0)
2041 return EFBIG;
2042
2043 name = expand_name(p->p_comm, p->p_ucred->cr_uid, p->p_pid);
2044 if (name == NULL)
2045 return (EINVAL);
2046 error = nlookup_init(&nd, name, UIO_SYSSPACE, NLC_LOCKVP);
2047 if (error == 0)
2048 error = vn_open(&nd, NULL, O_CREAT | FWRITE | O_NOFOLLOW, S_IRUSR | S_IWUSR);
2049 kfree(name, M_TEMP);
2050 if (error) {
2051 nlookup_done(&nd);
2052 return (error);
2053 }
2054 vp = nd.nl_open_vp;
2055 nd.nl_open_vp = NULL;
2056 nlookup_done(&nd);
2057
2058 vn_unlock(vp);
2059 lf.l_whence = SEEK_SET;
2060 lf.l_start = 0;
2061 lf.l_len = 0;
2062 lf.l_type = F_WRLCK;
2063 error = VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, 0);
2064 if (error)
2065 goto out2;
2066
2067 /* Don't dump to non-regular files or files with links. */
2068 if (vp->v_type != VREG ||
2069 VOP_GETATTR(vp, &vattr) || vattr.va_nlink != 1) {
2070 error = EFAULT;
2071 goto out1;
2072 }
2073
2074 /* Don't dump to files current user does not own */
2075 if (vattr.va_uid != p->p_ucred->cr_uid) {
2076 error = EFAULT;
2077 goto out1;
2078 }
2079
2080 VATTR_NULL(&vattr);
2081 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
2082 vattr.va_size = 0;
2083 VOP_SETATTR(vp, &vattr, cred);
2084 p->p_acflag |= ACORE;
2085 vn_unlock(vp);
2086
2087 error = p->p_sysent->sv_coredump ?
2088 p->p_sysent->sv_coredump(lp, sig, vp, limit) : ENOSYS;
2089
2090 out1:
2091 lf.l_type = F_UNLCK;
2092 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, 0);
2093 out2:
2094 error1 = vn_close(vp, FWRITE);
2095 if (error == 0)
2096 error = error1;
2097 return (error);
2098 }
2099
2100 /*
2101 * Nonexistent system call-- signal process (may want to handle it).
2102 * Flag error in case process won't see signal immediately (blocked or ignored).
2103 */
2104 /* ARGSUSED */
2105 int
2106 sys_nosys(struct nosys_args *args)
2107 {
2108 lwpsignal(curproc, curthread->td_lwp, SIGSYS);
2109 return (EINVAL);
2110 }
2111
2112 /*
2113 * Send a SIGIO or SIGURG signal to a process or process group using
2114 * stored credentials rather than those of the current process.
2115 */
2116 void
2117 pgsigio(struct sigio *sigio, int sig, int checkctty)
2118 {
2119 if (sigio == NULL)
2120 return;
2121
2122 if (sigio->sio_pgid > 0) {
2123 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred,
2124 sigio->sio_proc))
2125 ksignal(sigio->sio_proc, sig);
2126 } else if (sigio->sio_pgid < 0) {
2127 struct proc *p;
2128
2129 lockmgr(&sigio->sio_pgrp->pg_lock, LK_EXCLUSIVE);
2130 LIST_FOREACH(p, &sigio->sio_pgrp->pg_members, p_pglist) {
2131 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, p) &&
2132 (checkctty == 0 || (p->p_flag & P_CONTROLT)))
2133 ksignal(p, sig);
2134 }
2135 lockmgr(&sigio->sio_pgrp->pg_lock, LK_RELEASE);
2136 }
2137 }
2138
2139 static int
2140 filt_sigattach(struct knote *kn)
2141 {
2142 struct proc *p = curproc;
2143
2144 kn->kn_ptr.p_proc = p;
2145 kn->kn_flags |= EV_CLEAR; /* automatically set */
2146
2147 /* XXX lock the proc here while adding to the list? */
2148 SLIST_INSERT_HEAD(&p->p_klist, kn, kn_selnext);
2149
2150 return (0);
2151 }
2152
2153 static void
2154 filt_sigdetach(struct knote *kn)
2155 {
2156 struct proc *p = kn->kn_ptr.p_proc;
2157
2158 SLIST_REMOVE(&p->p_klist, kn, knote, kn_selnext);
2159 }
2160
2161 /*
2162 * signal knotes are shared with proc knotes, so we apply a mask to
2163 * the hint in order to differentiate them from process hints. This
2164 * could be avoided by using a signal-specific knote list, but probably
2165 * isn't worth the trouble.
2166 */
2167 static int
2168 filt_signal(struct knote *kn, long hint)
2169 {
2170 if (hint & NOTE_SIGNAL) {
2171 hint &= ~NOTE_SIGNAL;
2172
2173 if (kn->kn_id == hint)
2174 kn->kn_data++;
2175 }
2176 return (kn->kn_data != 0);
2177 }
DragonFly BSD