?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
More multi-threaded support for virtualization. Move the save context
[dragonfly.git] / sys / kern / kern_sig.c
blob755b012565110061c1692380a4de9f176d14b38d
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 1.82 2007/07/01 01:11:35 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 lwp. If it will be caught
821 * immediately, deliver it with correct code. Otherwise, post it normally.
822 *
823 * These signals may ONLY be delivered to the specified lwp and may never
824 * be delivered to the process generically.
825 */
826 void
827 trapsignal(struct lwp *lp, int sig, u_long code)
828 {
829 struct proc *p = lp->lwp_proc;
830 struct sigacts *ps = p->p_sigacts;
831
832 /*
833 * If we are a virtual kernel running an emulated user process
834 * context, switch back to the virtual kernel context before
835 * trying to post the signal.
836 */
837 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) {
838 struct trapframe *tf = lp->lwp_md.md_regs;
839 tf->tf_trapno = 0;
840 vkernel_trap(lp, tf);
841 }
842
843
844 if ((p->p_flag & P_TRACED) == 0 && SIGISMEMBER(p->p_sigcatch, sig) &&
845 !SIGISMEMBER(lp->lwp_sigmask, sig)) {
846 lp->lwp_ru.ru_nsignals++;
847 #ifdef KTRACE
848 if (KTRPOINT(lp->lwp_thread, KTR_PSIG))
849 ktrpsig(p, sig, ps->ps_sigact[_SIG_IDX(sig)],
850 &lp->lwp_sigmask, code);
851 #endif
852 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)], sig,
853 &lp->lwp_sigmask, code);
854 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]);
855 if (!SIGISMEMBER(ps->ps_signodefer, sig))
856 SIGADDSET(lp->lwp_sigmask, sig);
857 if (SIGISMEMBER(ps->ps_sigreset, sig)) {
858 /*
859 * See kern_sigaction() for origin of this code.
860 */
861 SIGDELSET(p->p_sigcatch, sig);
862 if (sig != SIGCONT &&
863 sigprop(sig) & SA_IGNORE)
864 SIGADDSET(p->p_sigignore, sig);
865 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
866 }
867 } else {
868 lp->lwp_code = code; /* XXX for core dump/debugger */
869 lp->lwp_sig = sig; /* XXX to verify code */
870 lwpsignal(p, lp, sig);
871 }
872 }
873
874 /*
875 * Find a suitable lwp to deliver the signal to.
876 *
877 * Returns NULL if all lwps hold the signal blocked.
878 */
879 static struct lwp *
880 find_lwp_for_signal(struct proc *p, int sig)
881 {
882 struct lwp *lp;
883 struct lwp *run, *sleep, *stop;
884
885 /*
886 * If the running/preempted thread belongs to the proc to which
887 * the signal is being delivered and this thread does not block
888 * the signal, then we can avoid a context switch by delivering
889 * the signal to this thread, because it will return to userland
890 * soon anyways.
891 */
892 lp = lwkt_preempted_proc();
893 if (lp != NULL && lp->lwp_proc == p && !SIGISMEMBER(lp->lwp_sigmask, sig))
894 return (lp);
895
896 run = sleep = stop = NULL;
897 FOREACH_LWP_IN_PROC(lp, p) {
898 /*
899 * If the signal is being blocked by the lwp, then this
900 * lwp is not eligible for receiving the signal.
901 */
902 if (SIGISMEMBER(lp->lwp_sigmask, sig))
903 continue;
904
905 switch (lp->lwp_stat) {
906 case LSRUN:
907 run = lp;
908 break;
909
910 case LSSTOP:
911 stop = lp;
912 break;
913
914 case LSSLEEP:
915 if (lp->lwp_flag & LWP_SINTR)
916 sleep = lp;
917 break;
918 }
919 }
920
921 if (run != NULL)
922 return (run);
923 else if (sleep != NULL)
924 return (sleep);
925 else
926 return (stop);
927 }
928
929 /*
930 * Send the signal to the process. If the signal has an action, the action
931 * is usually performed by the target process rather than the caller; we add
932 * the signal to the set of pending signals for the process.
933 *
934 * Exceptions:
935 * o When a stop signal is sent to a sleeping process that takes the
936 * default action, the process is stopped without awakening it.
937 * o SIGCONT restarts stopped processes (or puts them back to sleep)
938 * regardless of the signal action (eg, blocked or ignored).
939 *
940 * Other ignored signals are discarded immediately.
941 */
942 void
943 ksignal(struct proc *p, int sig)
944 {
945 lwpsignal(p, NULL, sig);
946 }
947
948 /*
949 * The core for ksignal. lp may be NULL, then a suitable thread
950 * will be chosen. If not, lp MUST be a member of p.
951 */
952 void
953 lwpsignal(struct proc *p, struct lwp *lp, int sig)
954 {
955 int prop;
956 sig_t action;
957
958 if (sig > _SIG_MAXSIG || sig <= 0) {
959 kprintf("lwpsignal: signal %d\n", sig);
960 panic("lwpsignal signal number");
961 }
962
963 KKASSERT(lp == NULL || lp->lwp_proc == p);
964
965 crit_enter();
966 KNOTE(&p->p_klist, NOTE_SIGNAL | sig);
967 crit_exit();
968
969 prop = sigprop(sig);
970
971 /*
972 * If proc is traced, always give parent a chance;
973 * if signal event is tracked by procfs, give *that*
974 * a chance, as well.
975 */
976 if ((p->p_flag & P_TRACED) || (p->p_stops & S_SIG)) {
977 action = SIG_DFL;
978 } else {
979 /*
980 * Do not try to deliver signals to an exiting lwp. Note
981 * that we must still deliver the signal if P_WEXIT is set
982 * in the process flags.
983 */
984 if (lp && (lp->lwp_flag & LWP_WEXIT))
985 return;
986
987 /*
988 * Ig the signal is being ignored, then we forget about
989 * it immediately. NOTE: We don't set SIGCONT in p_sigignore,
990 * and if it is set to SIG_IGN, action will be SIG_DFL here.
991 */
992 if (SIGISMEMBER(p->p_sigignore, sig))
993 return;
994 if (SIGISMEMBER(p->p_sigcatch, sig))
995 action = SIG_CATCH;
996 else
997 action = SIG_DFL;
998 }
999
1000 /*
1001 * If continuing, clear any pending STOP signals.
1002 */
1003 if (prop & SA_CONT)
1004 SIG_STOPSIGMASK(p->p_siglist);
1005
1006 if (prop & SA_STOP) {
1007 /*
1008 * If sending a tty stop signal to a member of an orphaned
1009 * process group, discard the signal here if the action
1010 * is default; don't stop the process below if sleeping,
1011 * and don't clear any pending SIGCONT.
1012 */
1013 if (prop & SA_TTYSTOP && p->p_pgrp->pg_jobc == 0 &&
1014 action == SIG_DFL) {
1015 return;
1016 }
1017 SIG_CONTSIGMASK(p->p_siglist);
1018 }
1019
1020 crit_enter();
1021
1022 if (p->p_stat == SSTOP) {
1023 /*
1024 * Nobody can handle this signal, add it to the lwp or
1025 * process pending list
1026 */
1027 if (lp)
1028 SIGADDSET(lp->lwp_siglist, sig);
1029 else
1030 SIGADDSET(p->p_siglist, sig);
1031
1032 /*
1033 * If the process is stopped and is being traced, then no
1034 * further action is necessary.
1035 */
1036 if (p->p_flag & P_TRACED)
1037 goto out;
1038
1039 /*
1040 * If the process is stopped and receives a KILL signal,
1041 * make the process runnable.
1042 */
1043 if (sig == SIGKILL) {
1044 proc_unstop(p);
1045 goto active_process;
1046 }
1047
1048 /*
1049 * If the process is stopped and receives a CONT signal,
1050 * then try to make the process runnable again.
1051 */
1052 if (prop & SA_CONT) {
1053 /*
1054 * If SIGCONT is default (or ignored), we continue the
1055 * process but don't leave the signal in p_siglist, as
1056 * it has no further action. If SIGCONT is held, we
1057 * continue the process and leave the signal in
1058 * p_siglist. If the process catches SIGCONT, let it
1059 * handle the signal itself.
1060 */
1061 /* XXX what if the signal is being held blocked? */
1062 if (action == SIG_DFL)
1063 SIGDELSET(p->p_siglist, sig);
1064 proc_unstop(p);
1065 if (action == SIG_CATCH)
1066 goto active_process;
1067 goto out;
1068 }
1069
1070 /*
1071 * If the process is stopped and receives another STOP
1072 * signal, we do not need to stop it again. If we did
1073 * the shell could get confused.
1074 *
1075 * However, if the current/preempted lwp is part of the
1076 * process receiving the signal, we need to keep it,
1077 * so that this lwp can stop in issignal() later, as
1078 * we don't want to wait until it reaches userret!
1079 */
1080 if (prop & SA_STOP) {
1081 if (lwkt_preempted_proc() == NULL ||
1082 lwkt_preempted_proc()->lwp_proc != p)
1083 SIGDELSET(p->p_siglist, sig);
1084 }
1085
1086 /*
1087 * Otherwise the process is stopped and it received some
1088 * signal, which does not change its stopped state.
1089 *
1090 * We have to select one thread to set LWP_BREAKTSLEEP,
1091 * so that the current signal will break the sleep
1092 * as soon as a SA_CONT signal will unstop the process.
1093 */
1094 if (lp == NULL)
1095 lp = find_lwp_for_signal(p, sig);
1096 if (lp != NULL &&
1097 (lp->lwp_stat == LSSLEEP || lp->lwp_stat == LSSTOP))
1098 lp->lwp_flag |= LWP_BREAKTSLEEP;
1099 goto out;
1100
1101 /* NOTREACHED */
1102 }
1103 /* else not stopped */
1104 active_process:
1105
1106 /*
1107 * Never deliver a lwp-specific signal to a random lwp.
1108 */
1109 if (lp == NULL) {
1110 lp = find_lwp_for_signal(p, sig);
1111 if (lp && SIGISMEMBER(lp->lwp_sigmask, sig))
1112 lp = NULL;
1113 }
1114
1115 /*
1116 * Deliver to the process generically if (1) the signal is being
1117 * sent to any thread or (2) we could not find a thread to deliver
1118 * it to.
1119 */
1120 if (lp == NULL) {
1121 SIGADDSET(p->p_siglist, sig);
1122 goto out;
1123 }
1124
1125 /*
1126 * Deliver to a specific LWP whether it masks it or not. It will
1127 * not be dispatched if masked but we must still deliver it.
1128 */
1129 if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) &&
1130 (p->p_flag & P_TRACED) == 0) {
1131 p->p_nice = NZERO;
1132 }
1133
1134 /*
1135 * If the process receives a STOP signal which indeed needs to
1136 * stop the process, do so. If the process chose to catch the
1137 * signal, it will be treated like any other signal.
1138 */
1139 if ((prop & SA_STOP) && action == SIG_DFL) {
1140 /*
1141 * If a child holding parent blocked, stopping
1142 * could cause deadlock. Take no action at this
1143 * time.
1144 */
1145 if (p->p_flag & P_PPWAIT) {
1146 SIGADDSET(p->p_siglist, sig);
1147 goto out;
1148 }
1149
1150 /*
1151 * Do not actually try to manipulate the process, but simply
1152 * stop it. Lwps will stop as soon as they safely can.
1153 */
1154 p->p_xstat = sig;
1155 proc_stop(p);
1156 goto out;
1157 }
1158
1159 /*
1160 * If it is a CONT signal with default action, just ignore it.
1161 */
1162 if ((prop & SA_CONT) && action == SIG_DFL)
1163 goto out;
1164
1165 /*
1166 * Mark signal pending at this specific thread.
1167 */
1168 SIGADDSET(lp->lwp_siglist, sig);
1169
1170 lwp_signotify(lp);
1171
1172 out:
1173 crit_exit();
1174 }
1175
1176 void
1177 lwp_signotify(struct lwp *lp)
1178 {
1179 crit_enter();
1180 if (lp->lwp_stat == LSSLEEP || lp->lwp_stat == LSSTOP) {
1181 /*
1182 * Thread is in tsleep.
1183 */
1184
1185 /*
1186 * If the thread is sleeping uninterruptibly
1187 * we can't interrupt the sleep... the signal will
1188 * be noticed when the lwp returns through
1189 * trap() or syscall().
1190 *
1191 * Otherwise the signal can interrupt the sleep.
1192 *
1193 * If the process is traced, the lwp will handle the
1194 * tracing in issignal() when it returns to userland.
1195 */
1196 if (lp->lwp_flag & LWP_SINTR) {
1197 /*
1198 * Make runnable and break out of any tsleep as well.
1199 */
1200 lp->lwp_flag |= LWP_BREAKTSLEEP;
1201 setrunnable(lp);
1202 }
1203 } else {
1204 /*
1205 * Otherwise the thread is running
1206 *
1207 * LSRUN does nothing with the signal, other than kicking
1208 * ourselves if we are running.
1209 * SZOMB and SIDL mean that it will either never be noticed,
1210 * or noticed very soon.
1211 *
1212 * Note that lwp_thread may be NULL or may not be completely
1213 * initialized if the process is in the SIDL or SZOMB state.
1214 *
1215 * For SMP we may have to forward the request to another cpu.
1216 * YYY the MP lock prevents the target process from moving
1217 * to another cpu, see kern/kern_switch.c
1218 *
1219 * If the target thread is waiting on its message port,
1220 * wakeup the target thread so it can check (or ignore)
1221 * the new signal. YYY needs cleanup.
1222 */
1223 if (lp == lwkt_preempted_proc()) {
1224 signotify();
1225 } else if (lp->lwp_stat == LSRUN) {
1226 struct thread *td = lp->lwp_thread;
1227 struct proc *p = lp->lwp_proc;
1228
1229 KASSERT(td != NULL,
1230 ("pid %d/%d NULL lwp_thread stat %d flags %08x/%08x",
1231 p->p_pid, lp->lwp_tid, lp->lwp_stat,
1232 p->p_flag, lp->lwp_flag));
1233
1234 /*
1235 * To prevent a MP race with TDF_SINTR we must
1236 * schedule the thread on the correct cpu.
1237 */
1238 #ifdef SMP
1239 if (td->td_gd != mycpu)
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 }
1270
1271 #endif
1272
1273 void
1274 proc_stop(struct proc *p)
1275 {
1276 struct lwp *lp;
1277
1278 /* If somebody raced us, be happy with it */
1279 if (p->p_stat == SSTOP)
1280 return;
1281
1282 crit_enter();
1283 p->p_stat = SSTOP;
1284
1285 FOREACH_LWP_IN_PROC(lp, p) {
1286 switch (lp->lwp_stat) {
1287 case LSSTOP:
1288 /*
1289 * Do nothing, we are already counted in
1290 * p_nstopped.
1291 */
1292 break;
1293
1294 case LSSLEEP:
1295 /*
1296 * We're sleeping, but we will stop before
1297 * returning to userspace, so count us
1298 * as stopped as well. We set LWP_WSTOP
1299 * to signal the lwp that it should not
1300 * increase p_nstopped when reaching tstop().
1301 */
1302 if ((lp->lwp_flag & LWP_WSTOP) == 0) {
1303 lp->lwp_flag |= LWP_WSTOP;
1304 ++p->p_nstopped;
1305 }
1306 break;
1307
1308 case LSRUN:
1309 /*
1310 * We might notify ourself, but that's not
1311 * a problem.
1312 */
1313 lwp_signotify(lp);
1314 break;
1315 }
1316 }
1317
1318 if (p->p_nstopped == p->p_nthreads) {
1319 p->p_flag &= ~P_WAITED;
1320 wakeup(p->p_pptr);
1321 if ((p->p_pptr->p_sigacts->ps_flag & PS_NOCLDSTOP) == 0)
1322 ksignal(p->p_pptr, SIGCHLD);
1323 }
1324 crit_exit();
1325 }
1326
1327 void
1328 proc_unstop(struct proc *p)
1329 {
1330 struct lwp *lp;
1331
1332 if (p->p_stat != SSTOP)
1333 return;
1334
1335 crit_enter();
1336 p->p_stat = SACTIVE;
1337
1338 FOREACH_LWP_IN_PROC(lp, p) {
1339 switch (lp->lwp_stat) {
1340 case LSRUN:
1341 /*
1342 * Uh? Not stopped? Well, I guess that's okay.
1343 */
1344 if (bootverbose)
1345 kprintf("proc_unstop: lwp %d/%d not sleeping\n",
1346 p->p_pid, lp->lwp_tid);
1347 break;
1348
1349 case LSSLEEP:
1350 /*
1351 * Still sleeping. Don't bother waking it up.
1352 * However, if this thread was counted as
1353 * stopped, undo this.
1354 *
1355 * Nevertheless we call setrunnable() so that it
1356 * will wake up in case a signal or timeout arrived
1357 * in the meantime.
1358 */
1359 if (lp->lwp_flag & LWP_WSTOP) {
1360 --p->p_nstopped;
1361 } else {
1362 if (bootverbose)
1363 kprintf("proc_unstop: lwp %d/%d sleeping, not stopped\n",
1364 p->p_pid, lp->lwp_tid);
1365 }
1366 /* FALLTHROUGH */
1367
1368 case LSSTOP:
1369 setrunnable(lp);
1370 break;
1371
1372 }
1373 lp->lwp_flag &= ~LWP_WSTOP;
1374 }
1375 crit_exit();
1376 }
1377
1378 static int
1379 kern_sigtimedwait(sigset_t waitset, siginfo_t *info, struct timespec *timeout)
1380 {
1381 sigset_t savedmask, set;
1382 struct proc *p = curproc;
1383 struct lwp *lp = curthread->td_lwp;
1384 int error, sig, hz, timevalid = 0;
1385 struct timespec rts, ets, ts;
1386 struct timeval tv;
1387
1388 error = 0;
1389 sig = 0;
1390 SIG_CANTMASK(waitset);
1391 savedmask = lp->lwp_sigmask;
1392
1393 if (timeout) {
1394 if (timeout->tv_sec >= 0 && timeout->tv_nsec >= 0 &&
1395 timeout->tv_nsec < 1000000000) {
1396 timevalid = 1;
1397 getnanouptime(&rts);
1398 ets = rts;
1399 timespecadd(&ets, timeout);
1400 }
1401 }
1402
1403 for (;;) {
1404 set = lwp_sigpend(lp);
1405 SIGSETAND(set, waitset);
1406 if ((sig = sig_ffs(&set)) != 0) {
1407 SIGFILLSET(lp->lwp_sigmask);
1408 SIGDELSET(lp->lwp_sigmask, sig);
1409 SIG_CANTMASK(lp->lwp_sigmask);
1410 sig = issignal(lp);
1411 /*
1412 * It may be a STOP signal, in the case, issignal
1413 * returns 0, because we may stop there, and new
1414 * signal can come in, we should restart if we got
1415 * nothing.
1416 */
1417 if (sig == 0)
1418 continue;
1419 else
1420 break;
1421 }
1422
1423 /*
1424 * Previous checking got nothing, and we retried but still
1425 * got nothing, we should return the error status.
1426 */
1427 if (error)
1428 break;
1429
1430 /*
1431 * POSIX says this must be checked after looking for pending
1432 * signals.
1433 */
1434 if (timeout) {
1435 if (!timevalid) {
1436 error = EINVAL;
1437 break;
1438 }
1439 getnanouptime(&rts);
1440 if (timespeccmp(&rts, &ets, >=)) {
1441 error = EAGAIN;
1442 break;
1443 }
1444 ts = ets;
1445 timespecsub(&ts, &rts);
1446 TIMESPEC_TO_TIMEVAL(&tv, &ts);
1447 hz = tvtohz_high(&tv);
1448 } else
1449 hz = 0;
1450
1451 lp->lwp_sigmask = savedmask;
1452 SIGSETNAND(lp->lwp_sigmask, waitset);
1453 /*
1454 * We won't ever be woken up. Instead, our sleep will
1455 * be broken in lwpsignal().
1456 */
1457 error = tsleep(&p->p_sigacts, PCATCH, "sigwt", hz);
1458 if (timeout) {
1459 if (error == ERESTART) {
1460 /* can not restart a timeout wait. */
1461 error = EINTR;
1462 } else if (error == EAGAIN) {
1463 /* will calculate timeout by ourself. */
1464 error = 0;
1465 }
1466 }
1467 /* Retry ... */
1468 }
1469
1470 lp->lwp_sigmask = savedmask;
1471 if (sig) {
1472 error = 0;
1473 bzero(info, sizeof(*info));
1474 info->si_signo = sig;
1475 lwp_delsig(lp, sig); /* take the signal! */
1476
1477 if (sig == SIGKILL)
1478 sigexit(p, sig);
1479 }
1480 return (error);
1481 }
1482
1483 int
1484 sys_sigtimedwait(struct sigtimedwait_args *uap)
1485 {
1486 struct timespec ts;
1487 struct timespec *timeout;
1488 sigset_t set;
1489 siginfo_t info;
1490 int error;
1491
1492 if (uap->timeout) {
1493 error = copyin(uap->timeout, &ts, sizeof(ts));
1494 if (error)
1495 return (error);
1496 timeout = &ts;
1497 } else {
1498 timeout = NULL;
1499 }
1500 error = copyin(uap->set, &set, sizeof(set));
1501 if (error)
1502 return (error);
1503 error = kern_sigtimedwait(set, &info, timeout);
1504 if (error)
1505 return (error);
1506 if (uap->info)
1507 error = copyout(&info, uap->info, sizeof(info));
1508 /* Repost if we got an error. */
1509 /*
1510 * XXX lwp
1511 *
1512 * This could transform a thread-specific signal to another
1513 * thread / process pending signal.
1514 */
1515 if (error)
1516 ksignal(curproc, info.si_signo);
1517 else
1518 uap->sysmsg_result = info.si_signo;
1519 return (error);
1520 }
1521
1522 int
1523 sys_sigwaitinfo(struct sigwaitinfo_args *uap)
1524 {
1525 siginfo_t info;
1526 sigset_t set;
1527 int error;
1528
1529 error = copyin(uap->set, &set, sizeof(set));
1530 if (error)
1531 return (error);
1532 error = kern_sigtimedwait(set, &info, NULL);
1533 if (error)
1534 return (error);
1535 if (uap->info)
1536 error = copyout(&info, uap->info, sizeof(info));
1537 /* Repost if we got an error. */
1538 /*
1539 * XXX lwp
1540 *
1541 * This could transform a thread-specific signal to another
1542 * thread / process pending signal.
1543 */
1544 if (error)
1545 ksignal(curproc, info.si_signo);
1546 else
1547 uap->sysmsg_result = info.si_signo;
1548 return (error);
1549 }
1550
1551 /*
1552 * If the current process has received a signal that would interrupt a
1553 * system call, return EINTR or ERESTART as appropriate.
1554 */
1555 int
1556 iscaught(struct lwp *lp)
1557 {
1558 struct proc *p = lp->lwp_proc;
1559 int sig;
1560
1561 if (p) {
1562 if ((sig = CURSIG(lp)) != 0) {
1563 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig))
1564 return (EINTR);
1565 return (ERESTART);
1566 }
1567 }
1568 return(EWOULDBLOCK);
1569 }
1570
1571 /*
1572 * If the current process has received a signal (should be caught or cause
1573 * termination, should interrupt current syscall), return the signal number.
1574 * Stop signals with default action are processed immediately, then cleared;
1575 * they aren't returned. This is checked after each entry to the system for
1576 * a syscall or trap (though this can usually be done without calling issignal
1577 * by checking the pending signal masks in the CURSIG macro.) The normal call
1578 * sequence is
1579 *
1580 * This routine is called via CURSIG/__cursig and the MP lock might not be
1581 * held. Obtain the MP lock for the duration of the operation.
1582 *
1583 * while (sig = CURSIG(curproc))
1584 * postsig(sig);
1585 */
1586 int
1587 issignal(struct lwp *lp)
1588 {
1589 struct proc *p = lp->lwp_proc;
1590 sigset_t mask;
1591 int sig, prop;
1592
1593 get_mplock();
1594 for (;;) {
1595 int traced = (p->p_flag & P_TRACED) || (p->p_stops & S_SIG);
1596
1597 mask = lwp_sigpend(lp);
1598 SIGSETNAND(mask, lp->lwp_sigmask);
1599 if (p->p_flag & P_PPWAIT)
1600 SIG_STOPSIGMASK(mask);
1601 if (SIGISEMPTY(mask)) { /* no signal to send */
1602 rel_mplock();
1603 return (0);
1604 }
1605 sig = sig_ffs(&mask);
1606
1607 STOPEVENT(p, S_SIG, sig);
1608
1609 /*
1610 * We should see pending but ignored signals
1611 * only if P_TRACED was on when they were posted.
1612 */
1613 if (SIGISMEMBER(p->p_sigignore, sig) && (traced == 0)) {
1614 lwp_delsig(lp, sig);
1615 continue;
1616 }
1617 if ((p->p_flag & P_TRACED) && (p->p_flag & P_PPWAIT) == 0) {
1618 /*
1619 * If traced, always stop, and stay stopped until
1620 * released by the parent.
1621 *
1622 * NOTE: SSTOP may get cleared during the loop,
1623 * but we do not re-notify the parent if we have
1624 * to loop several times waiting for the parent
1625 * to let us continue.
1626 *
1627 * XXX not sure if this is still true
1628 */
1629 p->p_xstat = sig;
1630 proc_stop(p);
1631 do {
1632 tstop();
1633 } while (!trace_req(p) && (p->p_flag & P_TRACED));
1634
1635 /*
1636 * If parent wants us to take the signal,
1637 * then it will leave it in p->p_xstat;
1638 * otherwise we just look for signals again.
1639 */
1640 lwp_delsig(lp, sig); /* clear old signal */
1641 sig = p->p_xstat;
1642 if (sig == 0)
1643 continue;
1644
1645 /*
1646 * Put the new signal into p_siglist. If the
1647 * signal is being masked, look for other signals.
1648 *
1649 * XXX lwp might need a call to ksignal()
1650 */
1651 SIGADDSET(p->p_siglist, sig);
1652 if (SIGISMEMBER(lp->lwp_sigmask, sig))
1653 continue;
1654
1655 /*
1656 * If the traced bit got turned off, go back up
1657 * to the top to rescan signals. This ensures
1658 * that p_sig* and ps_sigact are consistent.
1659 */
1660 if ((p->p_flag & P_TRACED) == 0)
1661 continue;
1662 }
1663
1664 prop = sigprop(sig);
1665
1666 /*
1667 * Decide whether the signal should be returned.
1668 * Return the signal's number, or fall through
1669 * to clear it from the pending mask.
1670 */
1671 switch ((int)(intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) {
1672 case (int)SIG_DFL:
1673 /*
1674 * Don't take default actions on system processes.
1675 */
1676 if (p->p_pid <= 1) {
1677 #ifdef DIAGNOSTIC
1678 /*
1679 * Are you sure you want to ignore SIGSEGV
1680 * in init? XXX
1681 */
1682 kprintf("Process (pid %lu) got signal %d\n",
1683 (u_long)p->p_pid, sig);
1684 #endif
1685 break; /* == ignore */
1686 }
1687
1688 /*
1689 * Handle the in-kernel checkpoint action
1690 */
1691 if (prop & SA_CKPT) {
1692 checkpoint_signal_handler(lp);
1693 break;
1694 }
1695
1696 /*
1697 * If there is a pending stop signal to process
1698 * with default action, stop here,
1699 * then clear the signal. However,
1700 * if process is member of an orphaned
1701 * process group, ignore tty stop signals.
1702 */
1703 if (prop & SA_STOP) {
1704 if (p->p_flag & P_TRACED ||
1705 (p->p_pgrp->pg_jobc == 0 &&
1706 prop & SA_TTYSTOP))
1707 break; /* == ignore */
1708 p->p_xstat = sig;
1709 proc_stop(p);
1710 while (p->p_stat == SSTOP) {
1711 tstop();
1712 }
1713 break;
1714 } else if (prop & SA_IGNORE) {
1715 /*
1716 * Except for SIGCONT, shouldn't get here.
1717 * Default action is to ignore; drop it.
1718 */
1719 break; /* == ignore */
1720 } else {
1721 rel_mplock();
1722 return (sig);
1723 }
1724
1725 /*NOTREACHED*/
1726
1727 case (int)SIG_IGN:
1728 /*
1729 * Masking above should prevent us ever trying
1730 * to take action on an ignored signal other
1731 * than SIGCONT, unless process is traced.
1732 */
1733 if ((prop & SA_CONT) == 0 &&
1734 (p->p_flag & P_TRACED) == 0)
1735 kprintf("issignal\n");
1736 break; /* == ignore */
1737
1738 default:
1739 /*
1740 * This signal has an action, let
1741 * postsig() process it.
1742 */
1743 rel_mplock();
1744 return (sig);
1745 }
1746 lwp_delsig(lp, sig); /* take the signal! */
1747 }
1748 /* NOTREACHED */
1749 }
1750
1751 /*
1752 * Take the action for the specified signal
1753 * from the current set of pending signals.
1754 */
1755 void
1756 postsig(int sig)
1757 {
1758 struct lwp *lp = curthread->td_lwp;
1759 struct proc *p = lp->lwp_proc;
1760 struct sigacts *ps = p->p_sigacts;
1761 sig_t action;
1762 sigset_t returnmask;
1763 int code;
1764
1765 KASSERT(sig != 0, ("postsig"));
1766
1767 /*
1768 * If we are a virtual kernel running an emulated user process
1769 * context, switch back to the virtual kernel context before
1770 * trying to post the signal.
1771 */
1772 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) {
1773 struct trapframe *tf = lp->lwp_md.md_regs;
1774 tf->tf_trapno = 0;
1775 vkernel_trap(lp, tf);
1776 }
1777
1778 lwp_delsig(lp, sig);
1779 action = ps->ps_sigact[_SIG_IDX(sig)];
1780 #ifdef KTRACE
1781 if (KTRPOINT(lp->lwp_thread, KTR_PSIG))
1782 ktrpsig(p, sig, action, lp->lwp_flag & LWP_OLDMASK ?
1783 &lp->lwp_oldsigmask : &lp->lwp_sigmask, 0);
1784 #endif
1785 STOPEVENT(p, S_SIG, sig);
1786
1787 if (action == SIG_DFL) {
1788 /*
1789 * Default action, where the default is to kill
1790 * the process. (Other cases were ignored above.)
1791 */
1792 sigexit(p, sig);
1793 /* NOTREACHED */
1794 } else {
1795 /*
1796 * If we get here, the signal must be caught.
1797 */
1798 KASSERT(action != SIG_IGN && !SIGISMEMBER(lp->lwp_sigmask, sig),
1799 ("postsig action"));
1800
1801 crit_enter();
1802
1803 /*
1804 * Reset the signal handler if asked to
1805 */
1806 if (SIGISMEMBER(ps->ps_sigreset, sig)) {
1807 /*
1808 * See kern_sigaction() for origin of this code.
1809 */
1810 SIGDELSET(p->p_sigcatch, sig);
1811 if (sig != SIGCONT &&
1812 sigprop(sig) & SA_IGNORE)
1813 SIGADDSET(p->p_sigignore, sig);
1814 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
1815 }
1816
1817 /*
1818 * Handle the mailbox case. Copyout to the appropriate
1819 * location but do not generate a signal frame. The system
1820 * call simply returns EINTR and the user is responsible for
1821 * polling the mailbox.
1822 */
1823 if (SIGISMEMBER(ps->ps_sigmailbox, sig)) {
1824 int sig_copy = sig;
1825 copyout(&sig_copy, (void *)action, sizeof(int));
1826 curproc->p_flag |= P_MAILBOX;
1827 crit_exit();
1828 goto done;
1829 }
1830
1831 /*
1832 * Set the signal mask and calculate the mask to restore
1833 * when the signal function returns.
1834 *
1835 * Special case: user has done a sigsuspend. Here the
1836 * current mask is not of interest, but rather the
1837 * mask from before the sigsuspend is what we want
1838 * restored after the signal processing is completed.
1839 */
1840 if (lp->lwp_flag & LWP_OLDMASK) {
1841 returnmask = lp->lwp_oldsigmask;
1842 lp->lwp_flag &= ~LWP_OLDMASK;
1843 } else {
1844 returnmask = lp->lwp_sigmask;
1845 }
1846
1847 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]);
1848 if (!SIGISMEMBER(ps->ps_signodefer, sig))
1849 SIGADDSET(lp->lwp_sigmask, sig);
1850
1851 crit_exit();
1852 lp->lwp_ru.ru_nsignals++;
1853 if (lp->lwp_sig != sig) {
1854 code = 0;
1855 } else {
1856 code = lp->lwp_code;
1857 lp->lwp_code = 0;
1858 lp->lwp_sig = 0;
1859 }
1860 (*p->p_sysent->sv_sendsig)(action, sig, &returnmask, code);
1861 }
1862 done:
1863 ;
1864 }
1865
1866 /*
1867 * Kill the current process for stated reason.
1868 */
1869 void
1870 killproc(struct proc *p, char *why)
1871 {
1872 log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n",
1873 p->p_pid, p->p_comm,
1874 p->p_ucred ? p->p_ucred->cr_uid : -1, why);
1875 ksignal(p, SIGKILL);
1876 }
1877
1878 /*
1879 * Force the current process to exit with the specified signal, dumping core
1880 * if appropriate. We bypass the normal tests for masked and caught signals,
1881 * allowing unrecoverable failures to terminate the process without changing
1882 * signal state. Mark the accounting record with the signal termination.
1883 * If dumping core, save the signal number for the debugger. Calls exit and
1884 * does not return.
1885 */
1886 void
1887 sigexit(struct proc *p, int sig)
1888 {
1889 struct lwp *lp = FIRST_LWP_IN_PROC(p); /* XXX lwp */
1890
1891 p->p_acflag |= AXSIG;
1892 if (sigprop(sig) & SA_CORE) {
1893 lp->lwp_sig = sig;
1894 /*
1895 * Log signals which would cause core dumps
1896 * (Log as LOG_INFO to appease those who don't want
1897 * these messages.)
1898 * XXX : Todo, as well as euid, write out ruid too
1899 */
1900 if (coredump(lp, sig) == 0)
1901 sig |= WCOREFLAG;
1902 if (kern_logsigexit)
1903 log(LOG_INFO,
1904 "pid %d (%s), uid %d: exited on signal %d%s\n",
1905 p->p_pid, p->p_comm,
1906 p->p_ucred ? p->p_ucred->cr_uid : -1,
1907 sig &~ WCOREFLAG,
1908 sig & WCOREFLAG ? " (core dumped)" : "");
1909 }
1910 exit1(W_EXITCODE(0, sig));
1911 /* NOTREACHED */
1912 }
1913
1914 static char corefilename[MAXPATHLEN+1] = {"%N.core"};
1915 SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename,
1916 sizeof(corefilename), "process corefile name format string");
1917
1918 /*
1919 * expand_name(name, uid, pid)
1920 * Expand the name described in corefilename, using name, uid, and pid.
1921 * corefilename is a kprintf-like string, with three format specifiers:
1922 * %N name of process ("name")
1923 * %P process id (pid)
1924 * %U user id (uid)
1925 * For example, "%N.core" is the default; they can be disabled completely
1926 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P".
1927 * This is controlled by the sysctl variable kern.corefile (see above).
1928 */
1929
1930 static char *
1931 expand_name(const char *name, uid_t uid, pid_t pid)
1932 {
1933 char *temp;
1934 char buf[11]; /* Buffer for pid/uid -- max 4B */
1935 int i, n;
1936 char *format = corefilename;
1937 size_t namelen;
1938
1939 temp = kmalloc(MAXPATHLEN + 1, M_TEMP, M_NOWAIT);
1940 if (temp == NULL)
1941 return NULL;
1942 namelen = strlen(name);
1943 for (i = 0, n = 0; n < MAXPATHLEN && format[i]; i++) {
1944 int l;
1945 switch (format[i]) {
1946 case '%': /* Format character */
1947 i++;
1948 switch (format[i]) {
1949 case '%':
1950 temp[n++] = '%';
1951 break;
1952 case 'N': /* process name */
1953 if ((n + namelen) > MAXPATHLEN) {
1954 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n",
1955 pid, name, uid, temp, name);
1956 kfree(temp, M_TEMP);
1957 return NULL;
1958 }
1959 memcpy(temp+n, name, namelen);
1960 n += namelen;
1961 break;
1962 case 'P': /* process id */
1963 l = ksprintf(buf, "%u", pid);
1964 if ((n + l) > MAXPATHLEN) {
1965 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n",
1966 pid, name, uid, temp, name);
1967 kfree(temp, M_TEMP);
1968 return NULL;
1969 }
1970 memcpy(temp+n, buf, l);
1971 n += l;
1972 break;
1973 case 'U': /* user id */
1974 l = ksprintf(buf, "%u", uid);
1975 if ((n + l) > MAXPATHLEN) {
1976 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n",
1977 pid, name, uid, temp, name);
1978 kfree(temp, M_TEMP);
1979 return NULL;
1980 }
1981 memcpy(temp+n, buf, l);
1982 n += l;
1983 break;
1984 default:
1985 log(LOG_ERR, "Unknown format character %c in `%s'\n", format[i], format);
1986 }
1987 break;
1988 default:
1989 temp[n++] = format[i];
1990 }
1991 }
1992 temp[n] = '\0';
1993 return temp;
1994 }
1995
1996 /*
1997 * Dump a process' core. The main routine does some
1998 * policy checking, and creates the name of the coredump;
1999 * then it passes on a vnode and a size limit to the process-specific
2000 * coredump routine if there is one; if there _is not_ one, it returns
2001 * ENOSYS; otherwise it returns the error from the process-specific routine.
2002 *
2003 * The parameter `lp' is the lwp which triggered the coredump.
2004 */
2005
2006 static int
2007 coredump(struct lwp *lp, int sig)
2008 {
2009 struct proc *p = lp->lwp_proc;
2010 struct vnode *vp;
2011 struct ucred *cred = p->p_ucred;
2012 struct flock lf;
2013 struct nlookupdata nd;
2014 struct vattr vattr;
2015 int error, error1;
2016 char *name; /* name of corefile */
2017 off_t limit;
2018
2019 STOPEVENT(p, S_CORE, 0);
2020
2021 if (((sugid_coredump == 0) && p->p_flag & P_SUGID) || do_coredump == 0)
2022 return (EFAULT);
2023
2024 /*
2025 * Note that the bulk of limit checking is done after
2026 * the corefile is created. The exception is if the limit
2027 * for corefiles is 0, in which case we don't bother
2028 * creating the corefile at all. This layout means that
2029 * a corefile is truncated instead of not being created,
2030 * if it is larger than the limit.
2031 */
2032 limit = p->p_rlimit[RLIMIT_CORE].rlim_cur;
2033 if (limit == 0)
2034 return EFBIG;
2035
2036 name = expand_name(p->p_comm, p->p_ucred->cr_uid, p->p_pid);
2037 if (name == NULL)
2038 return (EINVAL);
2039 error = nlookup_init(&nd, name, UIO_SYSSPACE, NLC_LOCKVP);
2040 if (error == 0)
2041 error = vn_open(&nd, NULL, O_CREAT | FWRITE | O_NOFOLLOW, S_IRUSR | S_IWUSR);
2042 kfree(name, M_TEMP);
2043 if (error) {
2044 nlookup_done(&nd);
2045 return (error);
2046 }
2047 vp = nd.nl_open_vp;
2048 nd.nl_open_vp = NULL;
2049 nlookup_done(&nd);
2050
2051 vn_unlock(vp);
2052 lf.l_whence = SEEK_SET;
2053 lf.l_start = 0;
2054 lf.l_len = 0;
2055 lf.l_type = F_WRLCK;
2056 error = VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, 0);
2057 if (error)
2058 goto out2;
2059
2060 /* Don't dump to non-regular files or files with links. */
2061 if (vp->v_type != VREG ||
2062 VOP_GETATTR(vp, &vattr) || vattr.va_nlink != 1) {
2063 error = EFAULT;
2064 goto out1;
2065 }
2066
2067 VATTR_NULL(&vattr);
2068 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
2069 vattr.va_size = 0;
2070 VOP_SETATTR(vp, &vattr, cred);
2071 p->p_acflag |= ACORE;
2072 vn_unlock(vp);
2073
2074 error = p->p_sysent->sv_coredump ?
2075 p->p_sysent->sv_coredump(lp, sig, vp, limit) : ENOSYS;
2076
2077 out1:
2078 lf.l_type = F_UNLCK;
2079 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, 0);
2080 out2:
2081 error1 = vn_close(vp, FWRITE);
2082 if (error == 0)
2083 error = error1;
2084 return (error);
2085 }
2086
2087 /*
2088 * Nonexistent system call-- signal process (may want to handle it).
2089 * Flag error in case process won't see signal immediately (blocked or ignored).
2090 */
2091 /* ARGSUSED */
2092 int
2093 sys_nosys(struct nosys_args *args)
2094 {
2095 lwpsignal(curproc, curthread->td_lwp, SIGSYS);
2096 return (EINVAL);
2097 }
2098
2099 /*
2100 * Send a SIGIO or SIGURG signal to a process or process group using
2101 * stored credentials rather than those of the current process.
2102 */
2103 void
2104 pgsigio(struct sigio *sigio, int sig, int checkctty)
2105 {
2106 if (sigio == NULL)
2107 return;
2108
2109 if (sigio->sio_pgid > 0) {
2110 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred,
2111 sigio->sio_proc))
2112 ksignal(sigio->sio_proc, sig);
2113 } else if (sigio->sio_pgid < 0) {
2114 struct proc *p;
2115
2116 lockmgr(&sigio->sio_pgrp->pg_lock, LK_EXCLUSIVE);
2117 LIST_FOREACH(p, &sigio->sio_pgrp->pg_members, p_pglist) {
2118 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, p) &&
2119 (checkctty == 0 || (p->p_flag & P_CONTROLT)))
2120 ksignal(p, sig);
2121 }
2122 lockmgr(&sigio->sio_pgrp->pg_lock, LK_RELEASE);
2123 }
2124 }
2125
2126 static int
2127 filt_sigattach(struct knote *kn)
2128 {
2129 struct proc *p = curproc;
2130
2131 kn->kn_ptr.p_proc = p;
2132 kn->kn_flags |= EV_CLEAR; /* automatically set */
2133
2134 /* XXX lock the proc here while adding to the list? */
2135 SLIST_INSERT_HEAD(&p->p_klist, kn, kn_selnext);
2136
2137 return (0);
2138 }
2139
2140 static void
2141 filt_sigdetach(struct knote *kn)
2142 {
2143 struct proc *p = kn->kn_ptr.p_proc;
2144
2145 SLIST_REMOVE(&p->p_klist, kn, knote, kn_selnext);
2146 }
2147
2148 /*
2149 * signal knotes are shared with proc knotes, so we apply a mask to
2150 * the hint in order to differentiate them from process hints. This
2151 * could be avoided by using a signal-specific knote list, but probably
2152 * isn't worth the trouble.
2153 */
2154 static int
2155 filt_signal(struct knote *kn, long hint)
2156 {
2157 if (hint & NOTE_SIGNAL) {
2158 hint &= ~NOTE_SIGNAL;
2159
2160 if (kn->kn_id == hint)
2161 kn->kn_data++;
2162 }
2163 return (kn->kn_data != 0);
2164 }
DragonFly BSD