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HAMMER Utilities: Sync with recent work.
[dragonfly.git] / sys / kern / kern_sig.c
blob9104685c5efc887520d8047be2fcb362e3385fe9
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 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 lp = lwp_rb_tree_RB_LOOKUP(&p->p_lwp_tree, tid);
725 if (lp == NULL)
726 return (ESRCH);
727 }
728 if (sig)
729 lwpsignal(p, lp, sig);
730 return (0);
731 }
732 /*
733 * If we come here, pid is a special broadcast pid.
734 * This doesn't mix with a tid.
735 */
736 if (tid != -1)
737 return (EINVAL);
738 switch (pid) {
739 case -1: /* broadcast signal */
740 return (dokillpg(sig, 0, 1));
741 case 0: /* signal own process group */
742 return (dokillpg(sig, 0, 0));
743 default: /* negative explicit process group */
744 return (dokillpg(sig, -pid, 0));
745 }
746 /* NOTREACHED */
747 }
748
749 int
750 sys_kill(struct kill_args *uap)
751 {
752 int error;
753
754 error = kern_kill(uap->signum, uap->pid, -1);
755 return (error);
756 }
757
758 int
759 sys_lwp_kill(struct lwp_kill_args *uap)
760 {
761 int error;
762 pid_t pid = uap->pid;
763
764 /*
765 * A tid is mandatory for lwp_kill(), otherwise
766 * you could simply use kill().
767 */
768 if (uap->tid == -1)
769 return (EINVAL);
770
771 /*
772 * To save on a getpid() function call for intra-process
773 * signals, pid == -1 means current process.
774 */
775 if (pid == -1)
776 pid = curproc->p_pid;
777
778 error = kern_kill(uap->signum, pid, uap->tid);
779 return (error);
780 }
781
782 /*
783 * Send a signal to a process group.
784 */
785 void
786 gsignal(int pgid, int sig)
787 {
788 struct pgrp *pgrp;
789
790 if (pgid && (pgrp = pgfind(pgid)))
791 pgsignal(pgrp, sig, 0);
792 }
793
794 /*
795 * Send a signal to a process group. If checktty is 1,
796 * limit to members which have a controlling terminal.
797 *
798 * pg_lock interlocks against a fork that might be in progress, to
799 * ensure that the new child process picks up the signal.
800 */
801 void
802 pgsignal(struct pgrp *pgrp, int sig, int checkctty)
803 {
804 struct proc *p;
805
806 if (pgrp) {
807 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE);
808 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
809 if (checkctty == 0 || p->p_flag & P_CONTROLT)
810 ksignal(p, sig);
811 }
812 lockmgr(&pgrp->pg_lock, LK_RELEASE);
813 }
814 }
815
816 /*
817 * Send a signal caused by a trap to the current lwp. If it will be caught
818 * immediately, deliver it with correct code. Otherwise, post it normally.
819 *
820 * These signals may ONLY be delivered to the specified lwp and may never
821 * be delivered to the process generically.
822 */
823 void
824 trapsignal(struct lwp *lp, int sig, u_long code)
825 {
826 struct proc *p = lp->lwp_proc;
827 struct sigacts *ps = p->p_sigacts;
828
829 /*
830 * If we are a virtual kernel running an emulated user process
831 * context, switch back to the virtual kernel context before
832 * trying to post the signal.
833 */
834 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) {
835 struct trapframe *tf = lp->lwp_md.md_regs;
836 tf->tf_trapno = 0;
837 vkernel_trap(lp, tf);
838 }
839
840
841 if ((p->p_flag & P_TRACED) == 0 && SIGISMEMBER(p->p_sigcatch, sig) &&
842 !SIGISMEMBER(lp->lwp_sigmask, sig)) {
843 lp->lwp_ru.ru_nsignals++;
844 #ifdef KTRACE
845 if (KTRPOINT(lp->lwp_thread, KTR_PSIG))
846 ktrpsig(lp, sig, ps->ps_sigact[_SIG_IDX(sig)],
847 &lp->lwp_sigmask, code);
848 #endif
849 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)], sig,
850 &lp->lwp_sigmask, code);
851 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]);
852 if (!SIGISMEMBER(ps->ps_signodefer, sig))
853 SIGADDSET(lp->lwp_sigmask, sig);
854 if (SIGISMEMBER(ps->ps_sigreset, sig)) {
855 /*
856 * See kern_sigaction() for origin of this code.
857 */
858 SIGDELSET(p->p_sigcatch, sig);
859 if (sig != SIGCONT &&
860 sigprop(sig) & SA_IGNORE)
861 SIGADDSET(p->p_sigignore, sig);
862 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
863 }
864 } else {
865 lp->lwp_code = code; /* XXX for core dump/debugger */
866 lp->lwp_sig = sig; /* XXX to verify code */
867 lwpsignal(p, lp, sig);
868 }
869 }
870
871 /*
872 * Find a suitable lwp to deliver the signal to.
873 *
874 * Returns NULL if all lwps hold the signal blocked.
875 */
876 static struct lwp *
877 find_lwp_for_signal(struct proc *p, int sig)
878 {
879 struct lwp *lp;
880 struct lwp *run, *sleep, *stop;
881
882 /*
883 * If the running/preempted thread belongs to the proc to which
884 * the signal is being delivered and this thread does not block
885 * the signal, then we can avoid a context switch by delivering
886 * the signal to this thread, because it will return to userland
887 * soon anyways.
888 */
889 lp = lwkt_preempted_proc();
890 if (lp != NULL && lp->lwp_proc == p && !SIGISMEMBER(lp->lwp_sigmask, sig))
891 return (lp);
892
893 run = sleep = stop = NULL;
894 FOREACH_LWP_IN_PROC(lp, p) {
895 /*
896 * If the signal is being blocked by the lwp, then this
897 * lwp is not eligible for receiving the signal.
898 */
899 if (SIGISMEMBER(lp->lwp_sigmask, sig))
900 continue;
901
902 switch (lp->lwp_stat) {
903 case LSRUN:
904 run = lp;
905 break;
906
907 case LSSTOP:
908 stop = lp;
909 break;
910
911 case LSSLEEP:
912 if (lp->lwp_flag & LWP_SINTR)
913 sleep = lp;
914 break;
915 }
916 }
917
918 if (run != NULL)
919 return (run);
920 else if (sleep != NULL)
921 return (sleep);
922 else
923 return (stop);
924 }
925
926 /*
927 * Send the signal to the process. If the signal has an action, the action
928 * is usually performed by the target process rather than the caller; we add
929 * the signal to the set of pending signals for the process.
930 *
931 * Exceptions:
932 * o When a stop signal is sent to a sleeping process that takes the
933 * default action, the process is stopped without awakening it.
934 * o SIGCONT restarts stopped processes (or puts them back to sleep)
935 * regardless of the signal action (eg, blocked or ignored).
936 *
937 * Other ignored signals are discarded immediately.
938 */
939 void
940 ksignal(struct proc *p, int sig)
941 {
942 lwpsignal(p, NULL, sig);
943 }
944
945 /*
946 * The core for ksignal. lp may be NULL, then a suitable thread
947 * will be chosen. If not, lp MUST be a member of p.
948 */
949 void
950 lwpsignal(struct proc *p, struct lwp *lp, int sig)
951 {
952 int prop;
953 sig_t action;
954
955 if (sig > _SIG_MAXSIG || sig <= 0) {
956 kprintf("lwpsignal: signal %d\n", sig);
957 panic("lwpsignal signal number");
958 }
959
960 KKASSERT(lp == NULL || lp->lwp_proc == p);
961
962 crit_enter();
963 KNOTE(&p->p_klist, NOTE_SIGNAL | sig);
964 crit_exit();
965
966 prop = sigprop(sig);
967
968 /*
969 * If proc is traced, always give parent a chance;
970 * if signal event is tracked by procfs, give *that*
971 * a chance, as well.
972 */
973 if ((p->p_flag & P_TRACED) || (p->p_stops & S_SIG)) {
974 action = SIG_DFL;
975 } else {
976 /*
977 * Do not try to deliver signals to an exiting lwp. Note
978 * that we must still deliver the signal if P_WEXIT is set
979 * in the process flags.
980 */
981 if (lp && (lp->lwp_flag & LWP_WEXIT))
982 return;
983
984 /*
985 * Ig the signal is being ignored, then we forget about
986 * it immediately. NOTE: We don't set SIGCONT in p_sigignore,
987 * and if it is set to SIG_IGN, action will be SIG_DFL here.
988 */
989 if (SIGISMEMBER(p->p_sigignore, sig))
990 return;
991 if (SIGISMEMBER(p->p_sigcatch, sig))
992 action = SIG_CATCH;
993 else
994 action = SIG_DFL;
995 }
996
997 /*
998 * If continuing, clear any pending STOP signals.
999 */
1000 if (prop & SA_CONT)
1001 SIG_STOPSIGMASK(p->p_siglist);
1002
1003 if (prop & SA_STOP) {
1004 /*
1005 * If sending a tty stop signal to a member of an orphaned
1006 * process group, discard the signal here if the action
1007 * is default; don't stop the process below if sleeping,
1008 * and don't clear any pending SIGCONT.
1009 */
1010 if (prop & SA_TTYSTOP && p->p_pgrp->pg_jobc == 0 &&
1011 action == SIG_DFL) {
1012 return;
1013 }
1014 SIG_CONTSIGMASK(p->p_siglist);
1015 p->p_flag &= ~P_CONTINUED;
1016 }
1017
1018 crit_enter();
1019
1020 if (p->p_stat == SSTOP) {
1021 /*
1022 * Nobody can handle this signal, add it to the lwp or
1023 * process pending list
1024 */
1025 if (lp)
1026 SIGADDSET(lp->lwp_siglist, sig);
1027 else
1028 SIGADDSET(p->p_siglist, sig);
1029
1030 /*
1031 * If the process is stopped and is being traced, then no
1032 * further action is necessary.
1033 */
1034 if (p->p_flag & P_TRACED)
1035 goto out;
1036
1037 /*
1038 * If the process is stopped and receives a KILL signal,
1039 * make the process runnable.
1040 */
1041 if (sig == SIGKILL) {
1042 proc_unstop(p);
1043 goto active_process;
1044 }
1045
1046 /*
1047 * If the process is stopped and receives a CONT signal,
1048 * then try to make the process runnable again.
1049 */
1050 if (prop & SA_CONT) {
1051 /*
1052 * If SIGCONT is default (or ignored), we continue the
1053 * process but don't leave the signal in p_siglist, as
1054 * it has no further action. If SIGCONT is held, we
1055 * continue the process and leave the signal in
1056 * p_siglist. If the process catches SIGCONT, let it
1057 * handle the signal itself.
1058 */
1059 /* XXX what if the signal is being held blocked? */
1060 p->p_flag |= P_CONTINUED;
1061 wakeup(p->p_pptr);
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 LWPHOLD(lp);
1241 lwkt_send_ipiq(td->td_gd, signotify_remote, lp);
1242 } else
1243 #endif
1244 if (td->td_flags & TDF_SINTR)
1245 lwkt_schedule(td);
1246 }
1247 }
1248 crit_exit();
1249 }
1250
1251 #ifdef SMP
1252
1253 /*
1254 * This function is called via an IPI. We will be in a critical section but
1255 * the MP lock will NOT be held. Also note that by the time the ipi message
1256 * gets to us the process 'p' (arg) may no longer be scheduled or even valid.
1257 */
1258 static void
1259 signotify_remote(void *arg)
1260 {
1261 struct lwp *lp = arg;
1262
1263 if (lp == lwkt_preempted_proc()) {
1264 signotify();
1265 } else {
1266 struct thread *td = lp->lwp_thread;
1267 if (td->td_flags & TDF_SINTR)
1268 lwkt_schedule(td);
1269 }
1270 LWPRELE(lp);
1271 }
1272
1273 #endif
1274
1275 void
1276 proc_stop(struct proc *p)
1277 {
1278 struct lwp *lp;
1279
1280 /* If somebody raced us, be happy with it */
1281 if (p->p_stat == SSTOP)
1282 return;
1283
1284 crit_enter();
1285 p->p_stat = SSTOP;
1286
1287 FOREACH_LWP_IN_PROC(lp, p) {
1288 switch (lp->lwp_stat) {
1289 case LSSTOP:
1290 /*
1291 * Do nothing, we are already counted in
1292 * p_nstopped.
1293 */
1294 break;
1295
1296 case LSSLEEP:
1297 /*
1298 * We're sleeping, but we will stop before
1299 * returning to userspace, so count us
1300 * as stopped as well. We set LWP_WSTOP
1301 * to signal the lwp that it should not
1302 * increase p_nstopped when reaching tstop().
1303 */
1304 if ((lp->lwp_flag & LWP_WSTOP) == 0) {
1305 lp->lwp_flag |= LWP_WSTOP;
1306 ++p->p_nstopped;
1307 }
1308 break;
1309
1310 case LSRUN:
1311 /*
1312 * We might notify ourself, but that's not
1313 * a problem.
1314 */
1315 lwp_signotify(lp);
1316 break;
1317 }
1318 }
1319
1320 if (p->p_nstopped == p->p_nthreads) {
1321 p->p_flag &= ~P_WAITED;
1322 wakeup(p->p_pptr);
1323 if ((p->p_pptr->p_sigacts->ps_flag & PS_NOCLDSTOP) == 0)
1324 ksignal(p->p_pptr, SIGCHLD);
1325 }
1326 crit_exit();
1327 }
1328
1329 void
1330 proc_unstop(struct proc *p)
1331 {
1332 struct lwp *lp;
1333
1334 if (p->p_stat != SSTOP)
1335 return;
1336
1337 crit_enter();
1338 p->p_stat = SACTIVE;
1339
1340 FOREACH_LWP_IN_PROC(lp, p) {
1341 switch (lp->lwp_stat) {
1342 case LSRUN:
1343 /*
1344 * Uh? Not stopped? Well, I guess that's okay.
1345 */
1346 if (bootverbose)
1347 kprintf("proc_unstop: lwp %d/%d not sleeping\n",
1348 p->p_pid, lp->lwp_tid);
1349 break;
1350
1351 case LSSLEEP:
1352 /*
1353 * Still sleeping. Don't bother waking it up.
1354 * However, if this thread was counted as
1355 * stopped, undo this.
1356 *
1357 * Nevertheless we call setrunnable() so that it
1358 * will wake up in case a signal or timeout arrived
1359 * in the meantime.
1360 */
1361 if (lp->lwp_flag & LWP_WSTOP) {
1362 lp->lwp_flag &= ~LWP_WSTOP;
1363 --p->p_nstopped;
1364 } else {
1365 if (bootverbose)
1366 kprintf("proc_unstop: lwp %d/%d sleeping, not stopped\n",
1367 p->p_pid, lp->lwp_tid);
1368 }
1369 /* FALLTHROUGH */
1370
1371 case LSSTOP:
1372 setrunnable(lp);
1373 break;
1374
1375 }
1376 }
1377 crit_exit();
1378 }
1379
1380 static int
1381 kern_sigtimedwait(sigset_t waitset, siginfo_t *info, struct timespec *timeout)
1382 {
1383 sigset_t savedmask, set;
1384 struct proc *p = curproc;
1385 struct lwp *lp = curthread->td_lwp;
1386 int error, sig, hz, timevalid = 0;
1387 struct timespec rts, ets, ts;
1388 struct timeval tv;
1389
1390 error = 0;
1391 sig = 0;
1392 ets.tv_sec = 0; /* silence compiler warning */
1393 ets.tv_nsec = 0; /* silence compiler warning */
1394 SIG_CANTMASK(waitset);
1395 savedmask = lp->lwp_sigmask;
1396
1397 if (timeout) {
1398 if (timeout->tv_sec >= 0 && timeout->tv_nsec >= 0 &&
1399 timeout->tv_nsec < 1000000000) {
1400 timevalid = 1;
1401 getnanouptime(&rts);
1402 ets = rts;
1403 timespecadd(&ets, timeout);
1404 }
1405 }
1406
1407 for (;;) {
1408 set = lwp_sigpend(lp);
1409 SIGSETAND(set, waitset);
1410 if ((sig = sig_ffs(&set)) != 0) {
1411 SIGFILLSET(lp->lwp_sigmask);
1412 SIGDELSET(lp->lwp_sigmask, sig);
1413 SIG_CANTMASK(lp->lwp_sigmask);
1414 sig = issignal(lp);
1415 /*
1416 * It may be a STOP signal, in the case, issignal
1417 * returns 0, because we may stop there, and new
1418 * signal can come in, we should restart if we got
1419 * nothing.
1420 */
1421 if (sig == 0)
1422 continue;
1423 else
1424 break;
1425 }
1426
1427 /*
1428 * Previous checking got nothing, and we retried but still
1429 * got nothing, we should return the error status.
1430 */
1431 if (error)
1432 break;
1433
1434 /*
1435 * POSIX says this must be checked after looking for pending
1436 * signals.
1437 */
1438 if (timeout) {
1439 if (timevalid == 0) {
1440 error = EINVAL;
1441 break;
1442 }
1443 getnanouptime(&rts);
1444 if (timespeccmp(&rts, &ets, >=)) {
1445 error = EAGAIN;
1446 break;
1447 }
1448 ts = ets;
1449 timespecsub(&ts, &rts);
1450 TIMESPEC_TO_TIMEVAL(&tv, &ts);
1451 hz = tvtohz_high(&tv);
1452 } else
1453 hz = 0;
1454
1455 lp->lwp_sigmask = savedmask;
1456 SIGSETNAND(lp->lwp_sigmask, waitset);
1457 /*
1458 * We won't ever be woken up. Instead, our sleep will
1459 * be broken in lwpsignal().
1460 */
1461 error = tsleep(&p->p_sigacts, PCATCH, "sigwt", hz);
1462 if (timeout) {
1463 if (error == ERESTART) {
1464 /* can not restart a timeout wait. */
1465 error = EINTR;
1466 } else if (error == EAGAIN) {
1467 /* will calculate timeout by ourself. */
1468 error = 0;
1469 }
1470 }
1471 /* Retry ... */
1472 }
1473
1474 lp->lwp_sigmask = savedmask;
1475 if (sig) {
1476 error = 0;
1477 bzero(info, sizeof(*info));
1478 info->si_signo = sig;
1479 lwp_delsig(lp, sig); /* take the signal! */
1480
1481 if (sig == SIGKILL)
1482 sigexit(lp, sig);
1483 }
1484 return (error);
1485 }
1486
1487 int
1488 sys_sigtimedwait(struct sigtimedwait_args *uap)
1489 {
1490 struct timespec ts;
1491 struct timespec *timeout;
1492 sigset_t set;
1493 siginfo_t info;
1494 int error;
1495
1496 if (uap->timeout) {
1497 error = copyin(uap->timeout, &ts, sizeof(ts));
1498 if (error)
1499 return (error);
1500 timeout = &ts;
1501 } else {
1502 timeout = NULL;
1503 }
1504 error = copyin(uap->set, &set, sizeof(set));
1505 if (error)
1506 return (error);
1507 error = kern_sigtimedwait(set, &info, timeout);
1508 if (error)
1509 return (error);
1510 if (uap->info)
1511 error = copyout(&info, uap->info, sizeof(info));
1512 /* Repost if we got an error. */
1513 /*
1514 * XXX lwp
1515 *
1516 * This could transform a thread-specific signal to another
1517 * thread / process pending signal.
1518 */
1519 if (error)
1520 ksignal(curproc, info.si_signo);
1521 else
1522 uap->sysmsg_result = info.si_signo;
1523 return (error);
1524 }
1525
1526 int
1527 sys_sigwaitinfo(struct sigwaitinfo_args *uap)
1528 {
1529 siginfo_t info;
1530 sigset_t set;
1531 int error;
1532
1533 error = copyin(uap->set, &set, sizeof(set));
1534 if (error)
1535 return (error);
1536 error = kern_sigtimedwait(set, &info, NULL);
1537 if (error)
1538 return (error);
1539 if (uap->info)
1540 error = copyout(&info, uap->info, sizeof(info));
1541 /* Repost if we got an error. */
1542 /*
1543 * XXX lwp
1544 *
1545 * This could transform a thread-specific signal to another
1546 * thread / process pending signal.
1547 */
1548 if (error)
1549 ksignal(curproc, info.si_signo);
1550 else
1551 uap->sysmsg_result = info.si_signo;
1552 return (error);
1553 }
1554
1555 /*
1556 * If the current process has received a signal that would interrupt a
1557 * system call, return EINTR or ERESTART as appropriate.
1558 */
1559 int
1560 iscaught(struct lwp *lp)
1561 {
1562 struct proc *p = lp->lwp_proc;
1563 int sig;
1564
1565 if (p) {
1566 if ((sig = CURSIG(lp)) != 0) {
1567 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig))
1568 return (EINTR);
1569 return (ERESTART);
1570 }
1571 }
1572 return(EWOULDBLOCK);
1573 }
1574
1575 /*
1576 * If the current process has received a signal (should be caught or cause
1577 * termination, should interrupt current syscall), return the signal number.
1578 * Stop signals with default action are processed immediately, then cleared;
1579 * they aren't returned. This is checked after each entry to the system for
1580 * a syscall or trap (though this can usually be done without calling issignal
1581 * by checking the pending signal masks in the CURSIG macro.) The normal call
1582 * sequence is
1583 *
1584 * This routine is called via CURSIG/__cursig and the MP lock might not be
1585 * held. Obtain the MP lock for the duration of the operation.
1586 *
1587 * while (sig = CURSIG(curproc))
1588 * postsig(sig);
1589 */
1590 int
1591 issignal(struct lwp *lp)
1592 {
1593 struct proc *p = lp->lwp_proc;
1594 sigset_t mask;
1595 int sig, prop;
1596
1597 get_mplock();
1598 for (;;) {
1599 int traced = (p->p_flag & P_TRACED) || (p->p_stops & S_SIG);
1600
1601 mask = lwp_sigpend(lp);
1602 SIGSETNAND(mask, lp->lwp_sigmask);
1603 if (p->p_flag & P_PPWAIT)
1604 SIG_STOPSIGMASK(mask);
1605 if (SIGISEMPTY(mask)) { /* no signal to send */
1606 rel_mplock();
1607 return (0);
1608 }
1609 sig = sig_ffs(&mask);
1610
1611 STOPEVENT(p, S_SIG, sig);
1612
1613 /*
1614 * We should see pending but ignored signals
1615 * only if P_TRACED was on when they were posted.
1616 */
1617 if (SIGISMEMBER(p->p_sigignore, sig) && (traced == 0)) {
1618 lwp_delsig(lp, sig);
1619 continue;
1620 }
1621 if ((p->p_flag & P_TRACED) && (p->p_flag & P_PPWAIT) == 0) {
1622 /*
1623 * If traced, always stop, and stay stopped until
1624 * released by the parent.
1625 *
1626 * NOTE: SSTOP may get cleared during the loop,
1627 * but we do not re-notify the parent if we have
1628 * to loop several times waiting for the parent
1629 * to let us continue.
1630 *
1631 * XXX not sure if this is still true
1632 */
1633 p->p_xstat = sig;
1634 proc_stop(p);
1635 do {
1636 tstop();
1637 } while (!trace_req(p) && (p->p_flag & P_TRACED));
1638
1639 /*
1640 * If parent wants us to take the signal,
1641 * then it will leave it in p->p_xstat;
1642 * otherwise we just look for signals again.
1643 */
1644 lwp_delsig(lp, sig); /* clear old signal */
1645 sig = p->p_xstat;
1646 if (sig == 0)
1647 continue;
1648
1649 /*
1650 * Put the new signal into p_siglist. If the
1651 * signal is being masked, look for other signals.
1652 *
1653 * XXX lwp might need a call to ksignal()
1654 */
1655 SIGADDSET(p->p_siglist, sig);
1656 if (SIGISMEMBER(lp->lwp_sigmask, sig))
1657 continue;
1658
1659 /*
1660 * If the traced bit got turned off, go back up
1661 * to the top to rescan signals. This ensures
1662 * that p_sig* and ps_sigact are consistent.
1663 */
1664 if ((p->p_flag & P_TRACED) == 0)
1665 continue;
1666 }
1667
1668 prop = sigprop(sig);
1669
1670 /*
1671 * Decide whether the signal should be returned.
1672 * Return the signal's number, or fall through
1673 * to clear it from the pending mask.
1674 */
1675 switch ((int)(intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) {
1676 case (int)SIG_DFL:
1677 /*
1678 * Don't take default actions on system processes.
1679 */
1680 if (p->p_pid <= 1) {
1681 #ifdef DIAGNOSTIC
1682 /*
1683 * Are you sure you want to ignore SIGSEGV
1684 * in init? XXX
1685 */
1686 kprintf("Process (pid %lu) got signal %d\n",
1687 (u_long)p->p_pid, sig);
1688 #endif
1689 break; /* == ignore */
1690 }
1691
1692 /*
1693 * Handle the in-kernel checkpoint action
1694 */
1695 if (prop & SA_CKPT) {
1696 checkpoint_signal_handler(lp);
1697 break;
1698 }
1699
1700 /*
1701 * If there is a pending stop signal to process
1702 * with default action, stop here,
1703 * then clear the signal. However,
1704 * if process is member of an orphaned
1705 * process group, ignore tty stop signals.
1706 */
1707 if (prop & SA_STOP) {
1708 if (p->p_flag & P_TRACED ||
1709 (p->p_pgrp->pg_jobc == 0 &&
1710 prop & SA_TTYSTOP))
1711 break; /* == ignore */
1712 p->p_xstat = sig;
1713 proc_stop(p);
1714 while (p->p_stat == SSTOP) {
1715 tstop();
1716 }
1717 break;
1718 } else if (prop & SA_IGNORE) {
1719 /*
1720 * Except for SIGCONT, shouldn't get here.
1721 * Default action is to ignore; drop it.
1722 */
1723 break; /* == ignore */
1724 } else {
1725 rel_mplock();
1726 return (sig);
1727 }
1728
1729 /*NOTREACHED*/
1730
1731 case (int)SIG_IGN:
1732 /*
1733 * Masking above should prevent us ever trying
1734 * to take action on an ignored signal other
1735 * than SIGCONT, unless process is traced.
1736 */
1737 if ((prop & SA_CONT) == 0 &&
1738 (p->p_flag & P_TRACED) == 0)
1739 kprintf("issignal\n");
1740 break; /* == ignore */
1741
1742 default:
1743 /*
1744 * This signal has an action, let
1745 * postsig() process it.
1746 */
1747 rel_mplock();
1748 return (sig);
1749 }
1750 lwp_delsig(lp, sig); /* take the signal! */
1751 }
1752 /* NOTREACHED */
1753 }
1754
1755 /*
1756 * Take the action for the specified signal
1757 * from the current set of pending signals.
1758 */
1759 void
1760 postsig(int sig)
1761 {
1762 struct lwp *lp = curthread->td_lwp;
1763 struct proc *p = lp->lwp_proc;
1764 struct sigacts *ps = p->p_sigacts;
1765 sig_t action;
1766 sigset_t returnmask;
1767 int code;
1768
1769 KASSERT(sig != 0, ("postsig"));
1770
1771 /*
1772 * If we are a virtual kernel running an emulated user process
1773 * context, switch back to the virtual kernel context before
1774 * trying to post the signal.
1775 */
1776 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) {
1777 struct trapframe *tf = lp->lwp_md.md_regs;
1778 tf->tf_trapno = 0;
1779 vkernel_trap(lp, tf);
1780 }
1781
1782 lwp_delsig(lp, sig);
1783 action = ps->ps_sigact[_SIG_IDX(sig)];
1784 #ifdef KTRACE
1785 if (KTRPOINT(lp->lwp_thread, KTR_PSIG))
1786 ktrpsig(lp, sig, action, lp->lwp_flag & LWP_OLDMASK ?
1787 &lp->lwp_oldsigmask : &lp->lwp_sigmask, 0);
1788 #endif
1789 STOPEVENT(p, S_SIG, sig);
1790
1791 if (action == SIG_DFL) {
1792 /*
1793 * Default action, where the default is to kill
1794 * the process. (Other cases were ignored above.)
1795 */
1796 sigexit(lp, sig);
1797 /* NOTREACHED */
1798 } else {
1799 /*
1800 * If we get here, the signal must be caught.
1801 */
1802 KASSERT(action != SIG_IGN && !SIGISMEMBER(lp->lwp_sigmask, sig),
1803 ("postsig action"));
1804
1805 crit_enter();
1806
1807 /*
1808 * Reset the signal handler if asked to
1809 */
1810 if (SIGISMEMBER(ps->ps_sigreset, sig)) {
1811 /*
1812 * See kern_sigaction() for origin of this code.
1813 */
1814 SIGDELSET(p->p_sigcatch, sig);
1815 if (sig != SIGCONT &&
1816 sigprop(sig) & SA_IGNORE)
1817 SIGADDSET(p->p_sigignore, sig);
1818 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
1819 }
1820
1821 /*
1822 * Handle the mailbox case. Copyout to the appropriate
1823 * location but do not generate a signal frame. The system
1824 * call simply returns EINTR and the user is responsible for
1825 * polling the mailbox.
1826 */
1827 if (SIGISMEMBER(ps->ps_sigmailbox, sig)) {
1828 int sig_copy = sig;
1829 copyout(&sig_copy, (void *)action, sizeof(int));
1830 curproc->p_flag |= P_MAILBOX;
1831 crit_exit();
1832 goto done;
1833 }
1834
1835 /*
1836 * Set the signal mask and calculate the mask to restore
1837 * when the signal function returns.
1838 *
1839 * Special case: user has done a sigsuspend. Here the
1840 * current mask is not of interest, but rather the
1841 * mask from before the sigsuspend is what we want
1842 * restored after the signal processing is completed.
1843 */
1844 if (lp->lwp_flag & LWP_OLDMASK) {
1845 returnmask = lp->lwp_oldsigmask;
1846 lp->lwp_flag &= ~LWP_OLDMASK;
1847 } else {
1848 returnmask = lp->lwp_sigmask;
1849 }
1850
1851 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]);
1852 if (!SIGISMEMBER(ps->ps_signodefer, sig))
1853 SIGADDSET(lp->lwp_sigmask, sig);
1854
1855 crit_exit();
1856 lp->lwp_ru.ru_nsignals++;
1857 if (lp->lwp_sig != sig) {
1858 code = 0;
1859 } else {
1860 code = lp->lwp_code;
1861 lp->lwp_code = 0;
1862 lp->lwp_sig = 0;
1863 }
1864 (*p->p_sysent->sv_sendsig)(action, sig, &returnmask, code);
1865 }
1866 done:
1867 ;
1868 }
1869
1870 /*
1871 * Kill the current process for stated reason.
1872 */
1873 void
1874 killproc(struct proc *p, char *why)
1875 {
1876 log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n",
1877 p->p_pid, p->p_comm,
1878 p->p_ucred ? p->p_ucred->cr_uid : -1, why);
1879 ksignal(p, SIGKILL);
1880 }
1881
1882 /*
1883 * Force the current process to exit with the specified signal, dumping core
1884 * if appropriate. We bypass the normal tests for masked and caught signals,
1885 * allowing unrecoverable failures to terminate the process without changing
1886 * signal state. Mark the accounting record with the signal termination.
1887 * If dumping core, save the signal number for the debugger. Calls exit and
1888 * does not return.
1889 */
1890 void
1891 sigexit(struct lwp *lp, int sig)
1892 {
1893 struct proc *p = lp->lwp_proc;
1894
1895 p->p_acflag |= AXSIG;
1896 if (sigprop(sig) & SA_CORE) {
1897 lp->lwp_sig = sig;
1898 /*
1899 * Log signals which would cause core dumps
1900 * (Log as LOG_INFO to appease those who don't want
1901 * these messages.)
1902 * XXX : Todo, as well as euid, write out ruid too
1903 */
1904 if (coredump(lp, sig) == 0)
1905 sig |= WCOREFLAG;
1906 if (kern_logsigexit)
1907 log(LOG_INFO,
1908 "pid %d (%s), uid %d: exited on signal %d%s\n",
1909 p->p_pid, p->p_comm,
1910 p->p_ucred ? p->p_ucred->cr_uid : -1,
1911 sig &~ WCOREFLAG,
1912 sig & WCOREFLAG ? " (core dumped)" : "");
1913 }
1914 exit1(W_EXITCODE(0, sig));
1915 /* NOTREACHED */
1916 }
1917
1918 static char corefilename[MAXPATHLEN+1] = {"%N.core"};
1919 SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename,
1920 sizeof(corefilename), "process corefile name format string");
1921
1922 /*
1923 * expand_name(name, uid, pid)
1924 * Expand the name described in corefilename, using name, uid, and pid.
1925 * corefilename is a kprintf-like string, with three format specifiers:
1926 * %N name of process ("name")
1927 * %P process id (pid)
1928 * %U user id (uid)
1929 * For example, "%N.core" is the default; they can be disabled completely
1930 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P".
1931 * This is controlled by the sysctl variable kern.corefile (see above).
1932 */
1933
1934 static char *
1935 expand_name(const char *name, uid_t uid, pid_t pid)
1936 {
1937 char *temp;
1938 char buf[11]; /* Buffer for pid/uid -- max 4B */
1939 int i, n;
1940 char *format = corefilename;
1941 size_t namelen;
1942
1943 temp = kmalloc(MAXPATHLEN + 1, M_TEMP, M_NOWAIT);
1944 if (temp == NULL)
1945 return NULL;
1946 namelen = strlen(name);
1947 for (i = 0, n = 0; n < MAXPATHLEN && format[i]; i++) {
1948 int l;
1949 switch (format[i]) {
1950 case '%': /* Format character */
1951 i++;
1952 switch (format[i]) {
1953 case '%':
1954 temp[n++] = '%';
1955 break;
1956 case 'N': /* process name */
1957 if ((n + namelen) > MAXPATHLEN) {
1958 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n",
1959 pid, name, uid, temp, name);
1960 kfree(temp, M_TEMP);
1961 return NULL;
1962 }
1963 memcpy(temp+n, name, namelen);
1964 n += namelen;
1965 break;
1966 case 'P': /* process id */
1967 l = ksprintf(buf, "%u", pid);
1968 if ((n + l) > MAXPATHLEN) {
1969 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n",
1970 pid, name, uid, temp, name);
1971 kfree(temp, M_TEMP);
1972 return NULL;
1973 }
1974 memcpy(temp+n, buf, l);
1975 n += l;
1976 break;
1977 case 'U': /* user id */
1978 l = ksprintf(buf, "%u", uid);
1979 if ((n + l) > MAXPATHLEN) {
1980 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n",
1981 pid, name, uid, temp, name);
1982 kfree(temp, M_TEMP);
1983 return NULL;
1984 }
1985 memcpy(temp+n, buf, l);
1986 n += l;
1987 break;
1988 default:
1989 log(LOG_ERR, "Unknown format character %c in `%s'\n", format[i], format);
1990 }
1991 break;
1992 default:
1993 temp[n++] = format[i];
1994 }
1995 }
1996 temp[n] = '\0';
1997 return temp;
1998 }
1999
2000 /*
2001 * Dump a process' core. The main routine does some
2002 * policy checking, and creates the name of the coredump;
2003 * then it passes on a vnode and a size limit to the process-specific
2004 * coredump routine if there is one; if there _is not_ one, it returns
2005 * ENOSYS; otherwise it returns the error from the process-specific routine.
2006 *
2007 * The parameter `lp' is the lwp which triggered the coredump.
2008 */
2009
2010 static int
2011 coredump(struct lwp *lp, int sig)
2012 {
2013 struct proc *p = lp->lwp_proc;
2014 struct vnode *vp;
2015 struct ucred *cred = p->p_ucred;
2016 struct flock lf;
2017 struct nlookupdata nd;
2018 struct vattr vattr;
2019 int error, error1;
2020 char *name; /* name of corefile */
2021 off_t limit;
2022
2023 STOPEVENT(p, S_CORE, 0);
2024
2025 if (((sugid_coredump == 0) && p->p_flag & P_SUGID) || do_coredump == 0)
2026 return (EFAULT);
2027
2028 /*
2029 * Note that the bulk of limit checking is done after
2030 * the corefile is created. The exception is if the limit
2031 * for corefiles is 0, in which case we don't bother
2032 * creating the corefile at all. This layout means that
2033 * a corefile is truncated instead of not being created,
2034 * if it is larger than the limit.
2035 */
2036 limit = p->p_rlimit[RLIMIT_CORE].rlim_cur;
2037 if (limit == 0)
2038 return EFBIG;
2039
2040 name = expand_name(p->p_comm, p->p_ucred->cr_uid, p->p_pid);
2041 if (name == NULL)
2042 return (EINVAL);
2043 error = nlookup_init(&nd, name, UIO_SYSSPACE, NLC_LOCKVP);
2044 if (error == 0)
2045 error = vn_open(&nd, NULL, O_CREAT | FWRITE | O_NOFOLLOW, S_IRUSR | S_IWUSR);
2046 kfree(name, M_TEMP);
2047 if (error) {
2048 nlookup_done(&nd);
2049 return (error);
2050 }
2051 vp = nd.nl_open_vp;
2052 nd.nl_open_vp = NULL;
2053 nlookup_done(&nd);
2054
2055 vn_unlock(vp);
2056 lf.l_whence = SEEK_SET;
2057 lf.l_start = 0;
2058 lf.l_len = 0;
2059 lf.l_type = F_WRLCK;
2060 error = VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, 0);
2061 if (error)
2062 goto out2;
2063
2064 /* Don't dump to non-regular files or files with links. */
2065 if (vp->v_type != VREG ||
2066 VOP_GETATTR(vp, &vattr) || vattr.va_nlink != 1) {
2067 error = EFAULT;
2068 goto out1;
2069 }
2070
2071 /* Don't dump to files current user does not own */
2072 if (vattr.va_uid != p->p_ucred->cr_uid) {
2073 error = EFAULT;
2074 goto out1;
2075 }
2076
2077 VATTR_NULL(&vattr);
2078 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
2079 vattr.va_size = 0;
2080 VOP_SETATTR(vp, &vattr, cred);
2081 p->p_acflag |= ACORE;
2082 vn_unlock(vp);
2083
2084 error = p->p_sysent->sv_coredump ?
2085 p->p_sysent->sv_coredump(lp, sig, vp, limit) : ENOSYS;
2086
2087 out1:
2088 lf.l_type = F_UNLCK;
2089 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, 0);
2090 out2:
2091 error1 = vn_close(vp, FWRITE);
2092 if (error == 0)
2093 error = error1;
2094 return (error);
2095 }
2096
2097 /*
2098 * Nonexistent system call-- signal process (may want to handle it).
2099 * Flag error in case process won't see signal immediately (blocked or ignored).
2100 */
2101 /* ARGSUSED */
2102 int
2103 sys_nosys(struct nosys_args *args)
2104 {
2105 lwpsignal(curproc, curthread->td_lwp, SIGSYS);
2106 return (EINVAL);
2107 }
2108
2109 /*
2110 * Send a SIGIO or SIGURG signal to a process or process group using
2111 * stored credentials rather than those of the current process.
2112 */
2113 void
2114 pgsigio(struct sigio *sigio, int sig, int checkctty)
2115 {
2116 if (sigio == NULL)
2117 return;
2118
2119 if (sigio->sio_pgid > 0) {
2120 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred,
2121 sigio->sio_proc))
2122 ksignal(sigio->sio_proc, sig);
2123 } else if (sigio->sio_pgid < 0) {
2124 struct proc *p;
2125
2126 lockmgr(&sigio->sio_pgrp->pg_lock, LK_EXCLUSIVE);
2127 LIST_FOREACH(p, &sigio->sio_pgrp->pg_members, p_pglist) {
2128 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, p) &&
2129 (checkctty == 0 || (p->p_flag & P_CONTROLT)))
2130 ksignal(p, sig);
2131 }
2132 lockmgr(&sigio->sio_pgrp->pg_lock, LK_RELEASE);
2133 }
2134 }
2135
2136 static int
2137 filt_sigattach(struct knote *kn)
2138 {
2139 struct proc *p = curproc;
2140
2141 kn->kn_ptr.p_proc = p;
2142 kn->kn_flags |= EV_CLEAR; /* automatically set */
2143
2144 /* XXX lock the proc here while adding to the list? */
2145 SLIST_INSERT_HEAD(&p->p_klist, kn, kn_selnext);
2146
2147 return (0);
2148 }
2149
2150 static void
2151 filt_sigdetach(struct knote *kn)
2152 {
2153 struct proc *p = kn->kn_ptr.p_proc;
2154
2155 SLIST_REMOVE(&p->p_klist, kn, knote, kn_selnext);
2156 }
2157
2158 /*
2159 * signal knotes are shared with proc knotes, so we apply a mask to
2160 * the hint in order to differentiate them from process hints. This
2161 * could be avoided by using a signal-specific knote list, but probably
2162 * isn't worth the trouble.
2163 */
2164 static int
2165 filt_signal(struct knote *kn, long hint)
2166 {
2167 if (hint & NOTE_SIGNAL) {
2168 hint &= ~NOTE_SIGNAL;
2169
2170 if (kn->kn_id == hint)
2171 kn->kn_data++;
2172 }
2173 return (kn->kn_data != 0);
2174 }
DragonFly BSD