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1:1 Userland threading stage 4.8/4:
[dragonfly.git] / sys / kern / kern_sig.c
blob71b24ad8e3b062e5b728a009468719123d008a20
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 1.75 2007/03/12 21:07:42 corecode 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 int
697 kern_kill(int sig, pid_t pid, lwpid_t tid)
698 {
699 struct thread *td = curthread;
700 struct proc *p = td->td_proc;
701 struct lwp *lp = NULL;
702
703 if ((u_int)sig > _SIG_MAXSIG)
704 return (EINVAL);
705 if (pid > 0) {
706 /* kill single process */
707 if ((p = pfind(pid)) == NULL)
708 return (ESRCH);
709 if (!CANSIGNAL(p, sig))
710 return (EPERM);
711 if (tid != -1) {
712 FOREACH_LWP_IN_PROC(lp, p) {
713 if (lp->lwp_tid == tid)
714 break;
715 }
716 if (lp == NULL)
717 return (ESRCH);
718 }
719 if (sig)
720 lwpsignal(p, lp, sig);
721 return (0);
722 }
723 /*
724 * If we come here, pid is a special broadcast pid.
725 * This doesn't mix with a tid.
726 */
727 if (tid != -1)
728 return (EINVAL);
729 switch (pid) {
730 case -1: /* broadcast signal */
731 return (dokillpg(sig, 0, 1));
732 case 0: /* signal own process group */
733 return (dokillpg(sig, 0, 0));
734 default: /* negative explicit process group */
735 return (dokillpg(sig, -pid, 0));
736 }
737 /* NOTREACHED */
738 }
739
740 int
741 sys_kill(struct kill_args *uap)
742 {
743 int error;
744
745 error = kern_kill(uap->signum, uap->pid, -1);
746 return (error);
747 }
748
749 int
750 sys_lwp_kill(struct lwp_kill_args *uap)
751 {
752 int error;
753 pid_t pid = uap->pid;
754
755 /*
756 * A tid is mandatory for lwp_kill(), otherwise
757 * you could simply use kill().
758 */
759 if (uap->tid == -1)
760 return (EINVAL);
761
762 /*
763 * To save on a getpid() function call for intra-process
764 * signals, pid == -1 means current process.
765 */
766 if (pid == -1)
767 pid = curproc->p_pid;
768
769 error = kern_kill(uap->signum, pid, uap->tid);
770 return (error);
771 }
772
773 /*
774 * Send a signal to a process group.
775 */
776 void
777 gsignal(int pgid, int sig)
778 {
779 struct pgrp *pgrp;
780
781 if (pgid && (pgrp = pgfind(pgid)))
782 pgsignal(pgrp, sig, 0);
783 }
784
785 /*
786 * Send a signal to a process group. If checktty is 1,
787 * limit to members which have a controlling terminal.
788 *
789 * pg_lock interlocks against a fork that might be in progress, to
790 * ensure that the new child process picks up the signal.
791 */
792 void
793 pgsignal(struct pgrp *pgrp, int sig, int checkctty)
794 {
795 struct proc *p;
796
797 if (pgrp) {
798 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE);
799 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
800 if (checkctty == 0 || p->p_flag & P_CONTROLT)
801 ksignal(p, sig);
802 }
803 lockmgr(&pgrp->pg_lock, LK_RELEASE);
804 }
805 }
806
807 /*
808 * Send a signal caused by a trap to the current process.
809 * If it will be caught immediately, deliver it with correct code.
810 * Otherwise, post it normally.
811 */
812 void
813 trapsignal(struct lwp *lp, int sig, u_long code)
814 {
815 struct proc *p = lp->lwp_proc;
816 struct sigacts *ps = p->p_sigacts;
817
818 /*
819 * If we are a virtual kernel running an emulated user process
820 * context, switch back to the virtual kernel context before
821 * trying to post the signal.
822 */
823 if (p->p_vkernel && p->p_vkernel->vk_current) {
824 struct trapframe *tf = curthread->td_lwp->lwp_md.md_regs;
825 tf->tf_trapno = 0;
826 vkernel_trap(p, tf);
827 }
828
829
830 if ((p->p_flag & P_TRACED) == 0 && SIGISMEMBER(p->p_sigcatch, sig) &&
831 !SIGISMEMBER(lp->lwp_sigmask, sig)) {
832 lp->lwp_ru.ru_nsignals++;
833 #ifdef KTRACE
834 if (KTRPOINT(lp->lwp_thread, KTR_PSIG))
835 ktrpsig(p, sig, ps->ps_sigact[_SIG_IDX(sig)],
836 &lp->lwp_sigmask, code);
837 #endif
838 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)], sig,
839 &lp->lwp_sigmask, code);
840 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]);
841 if (!SIGISMEMBER(ps->ps_signodefer, sig))
842 SIGADDSET(lp->lwp_sigmask, sig);
843 if (SIGISMEMBER(ps->ps_sigreset, sig)) {
844 /*
845 * See kern_sigaction() for origin of this code.
846 */
847 SIGDELSET(p->p_sigcatch, sig);
848 if (sig != SIGCONT &&
849 sigprop(sig) & SA_IGNORE)
850 SIGADDSET(p->p_sigignore, sig);
851 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
852 }
853 } else {
854 lp->lwp_code = code; /* XXX for core dump/debugger */
855 lp->lwp_sig = sig; /* XXX to verify code */
856 lwpsignal(p, lp, sig);
857 }
858 }
859
860 /*
861 * Find a suitable lwp to deliver the signal to.
862 *
863 * Returns NULL if all lwps hold the signal blocked.
864 */
865 static struct lwp *
866 find_lwp_for_signal(struct proc *p, int sig)
867 {
868 struct lwp *lp;
869 struct lwp *run, *sleep, *stop;
870
871 /*
872 * If the running/preempted thread belongs to the proc to which
873 * the signal is being delivered and this thread does not block
874 * the signal, then we can avoid a context switch by delivering
875 * the signal to this thread, because it will return to userland
876 * soon anyways.
877 */
878 lp = lwkt_preempted_proc();
879 if (lp != NULL && lp->lwp_proc == p && !SIGISMEMBER(lp->lwp_sigmask, sig))
880 return (lp);
881
882 run = sleep = stop = NULL;
883 FOREACH_LWP_IN_PROC(lp, p) {
884 /*
885 * If the signal is being blocked by the lwp, then this
886 * lwp is not eligible for receiving the signal.
887 */
888 if (SIGISMEMBER(lp->lwp_sigmask, sig))
889 continue;
890
891 switch (lp->lwp_stat) {
892 case LSRUN:
893 run = lp;
894 break;
895
896 case LSSTOP:
897 stop = lp;
898 break;
899
900 case LSSLEEP:
901 if (lp->lwp_flag & LWP_SINTR)
902 sleep = lp;
903 break;
904 }
905 }
906
907 if (run != NULL)
908 return (run);
909 else if (sleep != NULL)
910 return (sleep);
911 else
912 return (stop);
913 }
914
915 /*
916 * Send the signal to the process. If the signal has an action, the action
917 * is usually performed by the target process rather than the caller; we add
918 * the signal to the set of pending signals for the process.
919 *
920 * Exceptions:
921 * o When a stop signal is sent to a sleeping process that takes the
922 * default action, the process is stopped without awakening it.
923 * o SIGCONT restarts stopped processes (or puts them back to sleep)
924 * regardless of the signal action (eg, blocked or ignored).
925 *
926 * Other ignored signals are discarded immediately.
927 */
928 void
929 ksignal(struct proc *p, int sig)
930 {
931 lwpsignal(p, NULL, sig);
932 }
933
934 /*
935 * The core for ksignal. lp may be NULL, then a suitable thread
936 * will be chosen. If not, lp MUST be a member of p.
937 */
938 void
939 lwpsignal(struct proc *p, struct lwp *lp, int sig)
940 {
941 int prop;
942 sig_t action;
943
944 if (sig > _SIG_MAXSIG || sig <= 0) {
945 kprintf("lwpsignal: signal %d\n", sig);
946 panic("lwpsignal signal number");
947 }
948
949 KKASSERT(lp == NULL || lp->lwp_proc == p);
950
951 crit_enter();
952 KNOTE(&p->p_klist, NOTE_SIGNAL | sig);
953 crit_exit();
954
955 prop = sigprop(sig);
956
957 /*
958 * If proc is traced, always give parent a chance;
959 * if signal event is tracked by procfs, give *that*
960 * a chance, as well.
961 */
962 if ((p->p_flag & P_TRACED) || (p->p_stops & S_SIG)) {
963 action = SIG_DFL;
964 } else {
965 /*
966 * If the signal is being ignored,
967 * then we forget about it immediately.
968 * (Note: we don't set SIGCONT in p_sigignore,
969 * and if it is set to SIG_IGN,
970 * action will be SIG_DFL here.)
971 */
972 if (SIGISMEMBER(p->p_sigignore, sig) || (p->p_flag & P_WEXIT))
973 return;
974 if (SIGISMEMBER(p->p_sigcatch, sig))
975 action = SIG_CATCH;
976 else
977 action = SIG_DFL;
978 }
979
980 /*
981 * If continuing, clear any pending STOP signals.
982 */
983 if (prop & SA_CONT)
984 SIG_STOPSIGMASK(p->p_siglist);
985
986 if (prop & SA_STOP) {
987 /*
988 * If sending a tty stop signal to a member of an orphaned
989 * process group, discard the signal here if the action
990 * is default; don't stop the process below if sleeping,
991 * and don't clear any pending SIGCONT.
992 */
993 if (prop & SA_TTYSTOP && p->p_pgrp->pg_jobc == 0 &&
994 action == SIG_DFL) {
995 return;
996 }
997 SIG_CONTSIGMASK(p->p_siglist);
998 }
999
1000 crit_enter();
1001
1002 if (p->p_stat == SSTOP) {
1003 /*
1004 * Nobody can handle this signal, so add it to the process
1005 * pending list.
1006 */
1007 SIGADDSET(p->p_siglist, sig);
1008
1009 /*
1010 * If the process is stopped and is being traced, then no
1011 * further action is necessary.
1012 */
1013 if (p->p_flag & P_TRACED)
1014 goto out;
1015
1016 /*
1017 * If the process is stopped and receives a KILL signal,
1018 * make the process runnable.
1019 */
1020 if (sig == SIGKILL) {
1021 proc_unstop(p);
1022 goto active_process;
1023 }
1024
1025 /*
1026 * If the process is stopped and receives a CONT signal,
1027 * then try to make the process runnable again.
1028 */
1029 if (prop & SA_CONT) {
1030 /*
1031 * If SIGCONT is default (or ignored), we continue the
1032 * process but don't leave the signal in p_siglist, as
1033 * it has no further action. If SIGCONT is held, we
1034 * continue the process and leave the signal in
1035 * p_siglist. If the process catches SIGCONT, let it
1036 * handle the signal itself.
1037 */
1038 /* XXX what if the signal is being held blocked? */
1039 if (action == SIG_DFL)
1040 SIGDELSET(p->p_siglist, sig);
1041 proc_unstop(p);
1042 if (action == SIG_CATCH)
1043 goto active_process;
1044 goto out;
1045 }
1046
1047 /*
1048 * If the process is stopped and receives another STOP
1049 * signal, we do not need to stop it again. If we did
1050 * the shell could get confused.
1051 *
1052 * However, if the current/preempted lwp is part of the
1053 * process receiving the signal, we need to keep it,
1054 * so that this lwp can stop in issignal() later, as
1055 * we don't want to wait until it reaches userret!
1056 */
1057 if (prop & SA_STOP) {
1058 if (lwkt_preempted_proc() == NULL ||
1059 lwkt_preempted_proc()->lwp_proc != p)
1060 SIGDELSET(p->p_siglist, sig);
1061 }
1062
1063 /*
1064 * Otherwise the process is stopped and it received some
1065 * signal, which does not change its stopped state.
1066 *
1067 * We have to select one thread to set LWP_BREAKTSLEEP,
1068 * so that the current signal will break the sleep
1069 * as soon as a SA_CONT signal will unstop the process.
1070 */
1071 if (lp == NULL)
1072 lp = find_lwp_for_signal(p, sig);
1073 if (lp != NULL &&
1074 (lp->lwp_stat == LSSLEEP || lp->lwp_stat == LSSTOP))
1075 lp->lwp_flag |= LWP_BREAKTSLEEP;
1076 goto out;
1077
1078 /* NOTREACHED */
1079 }
1080 /* else not stopped */
1081 active_process:
1082
1083 if (lp == NULL)
1084 lp = find_lwp_for_signal(p, sig);
1085
1086 /*
1087 * If lp == NULL, there is no thread available which does
1088 * not block the signal. If lp is set, it might be a thread
1089 * specific signal, so we have to check for the thread ignoring
1090 * the signal.
1091 *
1092 * If so, defer further processing for this signal.
1093 * Add the signal to the process pending list.
1094 */
1095 if (lp == NULL || SIGISMEMBER(lp->lwp_sigmask, sig)) {
1096 SIGADDSET(p->p_siglist, sig);
1097 goto out;
1098 }
1099 /* else we have a lwp to deliver the signal to */
1100
1101 if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) &&
1102 (p->p_flag & P_TRACED) == 0) {
1103 p->p_nice = NZERO;
1104 }
1105
1106 /*
1107 * If the process receives a STOP signal which indeed needs to
1108 * stop the process, do so. If the process chose to catch the
1109 * signal, it will be treated like any other signal.
1110 */
1111 if ((prop & SA_STOP) && action == SIG_DFL) {
1112 /*
1113 * If a child holding parent blocked, stopping
1114 * could cause deadlock. Take no action at this
1115 * time.
1116 */
1117 if (p->p_flag & P_PPWAIT) {
1118 SIGADDSET(p->p_siglist, sig);
1119 goto out;
1120 }
1121
1122 /*
1123 * Do not actually try to manipulate the process, but simply
1124 * stop it. Lwps will stop as soon as they safely can.
1125 */
1126 p->p_xstat = sig;
1127 proc_stop(p, 1);
1128 goto out;
1129 }
1130
1131 /*
1132 * If it is a CONT signal with default action, just ignore it.
1133 */
1134 if ((prop & SA_CONT) && action == SIG_DFL)
1135 goto out;
1136
1137 /*
1138 * Mark signal pending at this specific thread.
1139 */
1140 SIGADDSET(lp->lwp_siglist, sig);
1141
1142 lwp_signotify(lp);
1143
1144 out:
1145 crit_exit();
1146 }
1147
1148 void
1149 lwp_signotify(struct lwp *lp)
1150 {
1151 crit_enter();
1152 if (lp->lwp_stat == LSSLEEP || lp->lwp_stat == LSSTOP) {
1153 /*
1154 * Thread is in tsleep.
1155 */
1156
1157 /*
1158 * If the thread is sleeping uninterruptibly
1159 * we can't interrupt the sleep... the signal will
1160 * be noticed when the lwp returns through
1161 * trap() or syscall().
1162 *
1163 * Otherwise the signal can interrupt the sleep.
1164 *
1165 * If the process is traced, the lwp will handle the
1166 * tracing in issignal() when it returns to userland.
1167 */
1168 if (lp->lwp_flag & LWP_SINTR) {
1169 /*
1170 * Make runnable and break out of any tsleep as well.
1171 */
1172 lp->lwp_flag |= LWP_BREAKTSLEEP;
1173 setrunnable(lp);
1174 }
1175 } else {
1176 /*
1177 * Otherwise the thread is running
1178 *
1179 * LSRUN does nothing with the signal, other than kicking
1180 * ourselves if we are running.
1181 * SZOMB and SIDL mean that it will either never be noticed,
1182 * or noticed very soon.
1183 *
1184 * Note that lwp_thread may be NULL or may not be completely
1185 * initialized if the process is in the SIDL or SZOMB state.
1186 *
1187 * For SMP we may have to forward the request to another cpu.
1188 * YYY the MP lock prevents the target process from moving
1189 * to another cpu, see kern/kern_switch.c
1190 *
1191 * If the target thread is waiting on its message port,
1192 * wakeup the target thread so it can check (or ignore)
1193 * the new signal. YYY needs cleanup.
1194 */
1195 if (lp == lwkt_preempted_proc()) {
1196 signotify();
1197 } else if (lp->lwp_stat == LSRUN) {
1198 struct thread *td = lp->lwp_thread;
1199 struct proc *p = lp->lwp_proc;
1200
1201 KASSERT(td != NULL,
1202 ("pid %d/%d NULL lwp_thread stat %d flags %08x/%08x",
1203 p->p_pid, lp->lwp_tid, lp->lwp_stat,
1204 p->p_flag, lp->lwp_flag));
1205
1206 #ifdef SMP
1207 if (td->td_gd != mycpu)
1208 lwkt_send_ipiq(td->td_gd, signotify_remote, lp);
1209 else
1210 #endif
1211 if (td->td_msgport.mp_flags & MSGPORTF_WAITING)
1212 lwkt_schedule(td);
1213 }
1214 }
1215 crit_exit();
1216 }
1217
1218 #ifdef SMP
1219
1220 /*
1221 * This function is called via an IPI. We will be in a critical section but
1222 * the MP lock will NOT be held. Also note that by the time the ipi message
1223 * gets to us the process 'p' (arg) may no longer be scheduled or even valid.
1224 */
1225 static void
1226 signotify_remote(void *arg)
1227 {
1228 struct lwp *lp = arg;
1229
1230 if (lp == lwkt_preempted_proc()) {
1231 signotify();
1232 } else {
1233 struct thread *td = lp->lwp_thread;
1234 if (td->td_msgport.mp_flags & MSGPORTF_WAITING)
1235 lwkt_schedule(td);
1236 }
1237 }
1238
1239 #endif
1240
1241 void
1242 proc_stop(struct proc *p, int notify)
1243 {
1244 struct lwp *lp, *preempted;
1245 int stopped;
1246
1247 /* If somebody raced us, be happy with it */
1248 if (p->p_stat == SSTOP)
1249 return;
1250
1251 p->p_stat = SSTOP;
1252
1253 preempted = lwkt_preempted_proc();
1254 stopped = 0;
1255 FOREACH_LWP_IN_PROC(lp, p) {
1256 switch (lp->lwp_stat) {
1257 case LSSTOP:
1258 /*
1259 * Do nothing, we are already counted in
1260 * p_nstopped.
1261 */
1262 break;
1263
1264 case LSSLEEP:
1265 /*
1266 * We're sleeping, but we will stop before
1267 * returning to userspace, so count us
1268 * as stopped as well. Don't increment
1269 * p_nstopped, that will happen in tstop().
1270 */
1271 ++stopped;
1272 break;
1273
1274 case LSRUN:
1275 lwp_signotify(lp);
1276 /*
1277 * No need to wait for the preempted/current
1278 * lwp. It will stop on return to userland
1279 * later, so consider it as stopped.
1280 */
1281 if (lp == preempted)
1282 ++stopped;
1283 break;
1284 }
1285 }
1286
1287 while (p->p_nstopped + stopped < p->p_nthreads)
1288 tsleep(&p->p_nstopped, 0, "pstop", hz);
1289
1290 p->p_flag &= ~P_WAITED;
1291 wakeup(p->p_pptr);
1292 if (notify > 1 ||
1293 (notify && (p->p_pptr->p_sigacts->ps_flag & PS_NOCLDSTOP) == 0))
1294 ksignal(p->p_pptr, SIGCHLD);
1295 }
1296
1297 void
1298 proc_unstop(struct proc *p)
1299 {
1300 struct lwp *lp;
1301
1302 if (p->p_stat != SSTOP)
1303 return;
1304 p->p_stat = SACTIVE;
1305
1306 FOREACH_LWP_IN_PROC(lp, p) {
1307 switch (lp->lwp_stat) {
1308 case LSRUN:
1309 /*
1310 * Uh? Not stopped? Well, I guess that's okay.
1311 */
1312 if (bootverbose)
1313 kprintf("proc_unstop: lwp %d/%d not sleeping\n",
1314 p->p_pid, lp->lwp_tid);
1315 break;
1316
1317 case LSSTOP:
1318 setrunnable(lp);
1319 break;
1320
1321 case LSSLEEP:
1322 /*
1323 * Still sleeping. Don't bother waking it up.
1324 */
1325 break;
1326 }
1327 }
1328 }
1329
1330 static int
1331 kern_sigtimedwait(sigset_t waitset, siginfo_t *info, struct timespec *timeout)
1332 {
1333 sigset_t savedmask, set;
1334 struct proc *p = curproc;
1335 struct lwp *lp = curthread->td_lwp;
1336 int error, sig, hz, timevalid = 0;
1337 struct timespec rts, ets, ts;
1338 struct timeval tv;
1339
1340 error = 0;
1341 sig = 0;
1342 SIG_CANTMASK(waitset);
1343 savedmask = lp->lwp_sigmask;
1344
1345 if (timeout) {
1346 if (timeout->tv_sec >= 0 && timeout->tv_nsec >= 0 &&
1347 timeout->tv_nsec < 1000000000) {
1348 timevalid = 1;
1349 getnanouptime(&rts);
1350 ets = rts;
1351 timespecadd(&ets, timeout);
1352 }
1353 }
1354
1355 for (;;) {
1356 set = lwp_sigpend(lp);
1357 SIGSETAND(set, waitset);
1358 if ((sig = sig_ffs(&set)) != 0) {
1359 SIGFILLSET(lp->lwp_sigmask);
1360 SIGDELSET(lp->lwp_sigmask, sig);
1361 SIG_CANTMASK(lp->lwp_sigmask);
1362 sig = issignal(lp);
1363 /*
1364 * It may be a STOP signal, in the case, issignal
1365 * returns 0, because we may stop there, and new
1366 * signal can come in, we should restart if we got
1367 * nothing.
1368 */
1369 if (sig == 0)
1370 continue;
1371 else
1372 break;
1373 }
1374
1375 /*
1376 * Previous checking got nothing, and we retried but still
1377 * got nothing, we should return the error status.
1378 */
1379 if (error)
1380 break;
1381
1382 /*
1383 * POSIX says this must be checked after looking for pending
1384 * signals.
1385 */
1386 if (timeout) {
1387 if (!timevalid) {
1388 error = EINVAL;
1389 break;
1390 }
1391 getnanouptime(&rts);
1392 if (timespeccmp(&rts, &ets, >=)) {
1393 error = EAGAIN;
1394 break;
1395 }
1396 ts = ets;
1397 timespecsub(&ts, &rts);
1398 TIMESPEC_TO_TIMEVAL(&tv, &ts);
1399 hz = tvtohz_high(&tv);
1400 } else
1401 hz = 0;
1402
1403 lp->lwp_sigmask = savedmask;
1404 SIGSETNAND(lp->lwp_sigmask, waitset);
1405 /*
1406 * We won't ever be woken up. Instead, our sleep will
1407 * be broken in lwpsignal().
1408 */
1409 error = tsleep(&p->p_sigacts, PCATCH, "sigwt", hz);
1410 if (timeout) {
1411 if (error == ERESTART) {
1412 /* can not restart a timeout wait. */
1413 error = EINTR;
1414 } else if (error == EAGAIN) {
1415 /* will calculate timeout by ourself. */
1416 error = 0;
1417 }
1418 }
1419 /* Retry ... */
1420 }
1421
1422 lp->lwp_sigmask = savedmask;
1423 if (sig) {
1424 error = 0;
1425 bzero(info, sizeof(*info));
1426 info->si_signo = sig;
1427 lwp_delsig(lp, sig); /* take the signal! */
1428
1429 if (sig == SIGKILL)
1430 sigexit(p, sig);
1431 }
1432 return (error);
1433 }
1434
1435 int
1436 sys_sigtimedwait(struct sigtimedwait_args *uap)
1437 {
1438 struct timespec ts;
1439 struct timespec *timeout;
1440 sigset_t set;
1441 siginfo_t info;
1442 int error;
1443
1444 if (uap->timeout) {
1445 error = copyin(uap->timeout, &ts, sizeof(ts));
1446 if (error)
1447 return (error);
1448 timeout = &ts;
1449 } else {
1450 timeout = NULL;
1451 }
1452 error = copyin(uap->set, &set, sizeof(set));
1453 if (error)
1454 return (error);
1455 error = kern_sigtimedwait(set, &info, timeout);
1456 if (error)
1457 return (error);
1458 if (uap->info)
1459 error = copyout(&info, uap->info, sizeof(info));
1460 /* Repost if we got an error. */
1461 /*
1462 * XXX lwp
1463 *
1464 * This could transform a thread-specific signal to another
1465 * thread / process pending signal.
1466 */
1467 if (error)
1468 ksignal(curproc, info.si_signo);
1469 else
1470 uap->sysmsg_result = info.si_signo;
1471 return (error);
1472 }
1473
1474 int
1475 sys_sigwaitinfo(struct sigwaitinfo_args *uap)
1476 {
1477 siginfo_t info;
1478 sigset_t set;
1479 int error;
1480
1481 error = copyin(uap->set, &set, sizeof(set));
1482 if (error)
1483 return (error);
1484 error = kern_sigtimedwait(set, &info, NULL);
1485 if (error)
1486 return (error);
1487 if (uap->info)
1488 error = copyout(&info, uap->info, sizeof(info));
1489 /* Repost if we got an error. */
1490 /*
1491 * XXX lwp
1492 *
1493 * This could transform a thread-specific signal to another
1494 * thread / process pending signal.
1495 */
1496 if (error)
1497 ksignal(curproc, info.si_signo);
1498 else
1499 uap->sysmsg_result = info.si_signo;
1500 return (error);
1501 }
1502
1503 /*
1504 * If the current process has received a signal that would interrupt a
1505 * system call, return EINTR or ERESTART as appropriate.
1506 */
1507 int
1508 iscaught(struct lwp *lp)
1509 {
1510 struct proc *p = lp->lwp_proc;
1511 int sig;
1512
1513 if (p) {
1514 if ((sig = CURSIG(lp)) != 0) {
1515 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig))
1516 return (EINTR);
1517 return (ERESTART);
1518 }
1519 }
1520 return(EWOULDBLOCK);
1521 }
1522
1523 /*
1524 * If the current process has received a signal (should be caught or cause
1525 * termination, should interrupt current syscall), return the signal number.
1526 * Stop signals with default action are processed immediately, then cleared;
1527 * they aren't returned. This is checked after each entry to the system for
1528 * a syscall or trap (though this can usually be done without calling issignal
1529 * by checking the pending signal masks in the CURSIG macro.) The normal call
1530 * sequence is
1531 *
1532 * This routine is called via CURSIG/__cursig and the MP lock might not be
1533 * held. Obtain the MP lock for the duration of the operation.
1534 *
1535 * while (sig = CURSIG(curproc))
1536 * postsig(sig);
1537 */
1538 int
1539 issignal(struct lwp *lp)
1540 {
1541 struct proc *p = lp->lwp_proc;
1542 sigset_t mask;
1543 int sig, prop;
1544
1545 get_mplock();
1546 for (;;) {
1547 int traced = (p->p_flag & P_TRACED) || (p->p_stops & S_SIG);
1548
1549 mask = lwp_sigpend(lp);
1550 SIGSETNAND(mask, lp->lwp_sigmask);
1551 if (p->p_flag & P_PPWAIT)
1552 SIG_STOPSIGMASK(mask);
1553 if (SIGISEMPTY(mask)) { /* no signal to send */
1554 rel_mplock();
1555 return (0);
1556 }
1557 sig = sig_ffs(&mask);
1558
1559 STOPEVENT(p, S_SIG, sig);
1560
1561 /*
1562 * We should see pending but ignored signals
1563 * only if P_TRACED was on when they were posted.
1564 */
1565 if (SIGISMEMBER(p->p_sigignore, sig) && (traced == 0)) {
1566 lwp_delsig(lp, sig);
1567 continue;
1568 }
1569 if ((p->p_flag & P_TRACED) && (p->p_flag & P_PPWAIT) == 0) {
1570 /*
1571 * If traced, always stop, and stay stopped until
1572 * released by the parent.
1573 *
1574 * NOTE: SSTOP may get cleared during the loop,
1575 * but we do not re-notify the parent if we have
1576 * to loop several times waiting for the parent
1577 * to let us continue.
1578 *
1579 * XXX not sure if this is still true
1580 */
1581 p->p_xstat = sig;
1582 proc_stop(p, 2);
1583 do {
1584 tstop();
1585 } while (!trace_req(p) && (p->p_flag & P_TRACED));
1586
1587 /*
1588 * If parent wants us to take the signal,
1589 * then it will leave it in p->p_xstat;
1590 * otherwise we just look for signals again.
1591 */
1592 lwp_delsig(lp, sig); /* clear old signal */
1593 sig = p->p_xstat;
1594 if (sig == 0)
1595 continue;
1596
1597 /*
1598 * Put the new signal into p_siglist. If the
1599 * signal is being masked, look for other signals.
1600 *
1601 * XXX lwp might need a call to ksignal()
1602 */
1603 SIGADDSET(p->p_siglist, sig);
1604 if (SIGISMEMBER(lp->lwp_sigmask, sig))
1605 continue;
1606
1607 /*
1608 * If the traced bit got turned off, go back up
1609 * to the top to rescan signals. This ensures
1610 * that p_sig* and ps_sigact are consistent.
1611 */
1612 if ((p->p_flag & P_TRACED) == 0)
1613 continue;
1614 }
1615
1616 prop = sigprop(sig);
1617
1618 /*
1619 * Decide whether the signal should be returned.
1620 * Return the signal's number, or fall through
1621 * to clear it from the pending mask.
1622 */
1623 switch ((int)(intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) {
1624 case (int)SIG_DFL:
1625 /*
1626 * Don't take default actions on system processes.
1627 */
1628 if (p->p_pid <= 1) {
1629 #ifdef DIAGNOSTIC
1630 /*
1631 * Are you sure you want to ignore SIGSEGV
1632 * in init? XXX
1633 */
1634 kprintf("Process (pid %lu) got signal %d\n",
1635 (u_long)p->p_pid, sig);
1636 #endif
1637 break; /* == ignore */
1638 }
1639
1640 /*
1641 * Handle the in-kernel checkpoint action
1642 */
1643 if (prop & SA_CKPT) {
1644 checkpoint_signal_handler(lp);
1645 break;
1646 }
1647
1648 /*
1649 * If there is a pending stop signal to process
1650 * with default action, stop here,
1651 * then clear the signal. However,
1652 * if process is member of an orphaned
1653 * process group, ignore tty stop signals.
1654 */
1655 if (prop & SA_STOP) {
1656 if (p->p_flag & P_TRACED ||
1657 (p->p_pgrp->pg_jobc == 0 &&
1658 prop & SA_TTYSTOP))
1659 break; /* == ignore */
1660 p->p_xstat = sig;
1661 proc_stop(p, 1);
1662 while (p->p_stat == SSTOP) {
1663 tstop();
1664 }
1665 break;
1666 } else if (prop & SA_IGNORE) {
1667 /*
1668 * Except for SIGCONT, shouldn't get here.
1669 * Default action is to ignore; drop it.
1670 */
1671 break; /* == ignore */
1672 } else {
1673 rel_mplock();
1674 return (sig);
1675 }
1676
1677 /*NOTREACHED*/
1678
1679 case (int)SIG_IGN:
1680 /*
1681 * Masking above should prevent us ever trying
1682 * to take action on an ignored signal other
1683 * than SIGCONT, unless process is traced.
1684 */
1685 if ((prop & SA_CONT) == 0 &&
1686 (p->p_flag & P_TRACED) == 0)
1687 kprintf("issignal\n");
1688 break; /* == ignore */
1689
1690 default:
1691 /*
1692 * This signal has an action, let
1693 * postsig() process it.
1694 */
1695 rel_mplock();
1696 return (sig);
1697 }
1698 lwp_delsig(lp, sig); /* take the signal! */
1699 }
1700 /* NOTREACHED */
1701 }
1702
1703 /*
1704 * Take the action for the specified signal
1705 * from the current set of pending signals.
1706 */
1707 void
1708 postsig(int sig)
1709 {
1710 struct lwp *lp = curthread->td_lwp;
1711 struct proc *p = lp->lwp_proc;
1712 struct sigacts *ps = p->p_sigacts;
1713 sig_t action;
1714 sigset_t returnmask;
1715 int code;
1716
1717 KASSERT(sig != 0, ("postsig"));
1718
1719 /*
1720 * If we are a virtual kernel running an emulated user process
1721 * context, switch back to the virtual kernel context before
1722 * trying to post the signal.
1723 */
1724 if (p->p_vkernel && p->p_vkernel->vk_current) {
1725 struct trapframe *tf = curthread->td_lwp->lwp_md.md_regs;
1726 tf->tf_trapno = 0;
1727 vkernel_trap(p, tf);
1728 }
1729
1730 lwp_delsig(lp, sig);
1731 action = ps->ps_sigact[_SIG_IDX(sig)];
1732 #ifdef KTRACE
1733 if (KTRPOINT(lp->lwp_thread, KTR_PSIG))
1734 ktrpsig(p, sig, action, lp->lwp_flag & LWP_OLDMASK ?
1735 &lp->lwp_oldsigmask : &lp->lwp_sigmask, 0);
1736 #endif
1737 STOPEVENT(p, S_SIG, sig);
1738
1739 if (action == SIG_DFL) {
1740 /*
1741 * Default action, where the default is to kill
1742 * the process. (Other cases were ignored above.)
1743 */
1744 sigexit(p, sig);
1745 /* NOTREACHED */
1746 } else {
1747 /*
1748 * If we get here, the signal must be caught.
1749 */
1750 KASSERT(action != SIG_IGN && !SIGISMEMBER(lp->lwp_sigmask, sig),
1751 ("postsig action"));
1752
1753 crit_enter();
1754
1755 /*
1756 * Reset the signal handler if asked to
1757 */
1758 if (SIGISMEMBER(ps->ps_sigreset, sig)) {
1759 /*
1760 * See kern_sigaction() for origin of this code.
1761 */
1762 SIGDELSET(p->p_sigcatch, sig);
1763 if (sig != SIGCONT &&
1764 sigprop(sig) & SA_IGNORE)
1765 SIGADDSET(p->p_sigignore, sig);
1766 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
1767 }
1768
1769 /*
1770 * Handle the mailbox case. Copyout to the appropriate
1771 * location but do not generate a signal frame. The system
1772 * call simply returns EINTR and the user is responsible for
1773 * polling the mailbox.
1774 */
1775 if (SIGISMEMBER(ps->ps_sigmailbox, sig)) {
1776 int sig_copy = sig;
1777 copyout(&sig_copy, (void *)action, sizeof(int));
1778 curproc->p_flag |= P_MAILBOX;
1779 crit_exit();
1780 goto done;
1781 }
1782
1783 /*
1784 * Set the signal mask and calculate the mask to restore
1785 * when the signal function returns.
1786 *
1787 * Special case: user has done a sigsuspend. Here the
1788 * current mask is not of interest, but rather the
1789 * mask from before the sigsuspend is what we want
1790 * restored after the signal processing is completed.
1791 */
1792 if (lp->lwp_flag & LWP_OLDMASK) {
1793 returnmask = lp->lwp_oldsigmask;
1794 lp->lwp_flag &= ~LWP_OLDMASK;
1795 } else {
1796 returnmask = lp->lwp_sigmask;
1797 }
1798
1799 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]);
1800 if (!SIGISMEMBER(ps->ps_signodefer, sig))
1801 SIGADDSET(lp->lwp_sigmask, sig);
1802
1803 crit_exit();
1804 lp->lwp_ru.ru_nsignals++;
1805 if (lp->lwp_sig != sig) {
1806 code = 0;
1807 } else {
1808 code = lp->lwp_code;
1809 lp->lwp_code = 0;
1810 lp->lwp_sig = 0;
1811 }
1812 (*p->p_sysent->sv_sendsig)(action, sig, &returnmask, code);
1813 }
1814 done:
1815 ;
1816 }
1817
1818 /*
1819 * Kill the current process for stated reason.
1820 */
1821 void
1822 killproc(struct proc *p, char *why)
1823 {
1824 log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n",
1825 p->p_pid, p->p_comm,
1826 p->p_ucred ? p->p_ucred->cr_uid : -1, why);
1827 ksignal(p, SIGKILL);
1828 }
1829
1830 /*
1831 * Force the current process to exit with the specified signal, dumping core
1832 * if appropriate. We bypass the normal tests for masked and caught signals,
1833 * allowing unrecoverable failures to terminate the process without changing
1834 * signal state. Mark the accounting record with the signal termination.
1835 * If dumping core, save the signal number for the debugger. Calls exit and
1836 * does not return.
1837 */
1838 void
1839 sigexit(struct proc *p, int sig)
1840 {
1841 struct lwp *lp = FIRST_LWP_IN_PROC(p); /* XXX lwp */
1842
1843 p->p_acflag |= AXSIG;
1844 if (sigprop(sig) & SA_CORE) {
1845 lp->lwp_sig = sig;
1846 /*
1847 * Log signals which would cause core dumps
1848 * (Log as LOG_INFO to appease those who don't want
1849 * these messages.)
1850 * XXX : Todo, as well as euid, write out ruid too
1851 */
1852 if (coredump(lp, sig) == 0)
1853 sig |= WCOREFLAG;
1854 if (kern_logsigexit)
1855 log(LOG_INFO,
1856 "pid %d (%s), uid %d: exited on signal %d%s\n",
1857 p->p_pid, p->p_comm,
1858 p->p_ucred ? p->p_ucred->cr_uid : -1,
1859 sig &~ WCOREFLAG,
1860 sig & WCOREFLAG ? " (core dumped)" : "");
1861 }
1862 exit1(W_EXITCODE(0, sig));
1863 /* NOTREACHED */
1864 }
1865
1866 static char corefilename[MAXPATHLEN+1] = {"%N.core"};
1867 SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename,
1868 sizeof(corefilename), "process corefile name format string");
1869
1870 /*
1871 * expand_name(name, uid, pid)
1872 * Expand the name described in corefilename, using name, uid, and pid.
1873 * corefilename is a kprintf-like string, with three format specifiers:
1874 * %N name of process ("name")
1875 * %P process id (pid)
1876 * %U user id (uid)
1877 * For example, "%N.core" is the default; they can be disabled completely
1878 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P".
1879 * This is controlled by the sysctl variable kern.corefile (see above).
1880 */
1881
1882 static char *
1883 expand_name(const char *name, uid_t uid, pid_t pid)
1884 {
1885 char *temp;
1886 char buf[11]; /* Buffer for pid/uid -- max 4B */
1887 int i, n;
1888 char *format = corefilename;
1889 size_t namelen;
1890
1891 temp = kmalloc(MAXPATHLEN + 1, M_TEMP, M_NOWAIT);
1892 if (temp == NULL)
1893 return NULL;
1894 namelen = strlen(name);
1895 for (i = 0, n = 0; n < MAXPATHLEN && format[i]; i++) {
1896 int l;
1897 switch (format[i]) {
1898 case '%': /* Format character */
1899 i++;
1900 switch (format[i]) {
1901 case '%':
1902 temp[n++] = '%';
1903 break;
1904 case 'N': /* process name */
1905 if ((n + namelen) > MAXPATHLEN) {
1906 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n",
1907 pid, name, uid, temp, name);
1908 kfree(temp, M_TEMP);
1909 return NULL;
1910 }
1911 memcpy(temp+n, name, namelen);
1912 n += namelen;
1913 break;
1914 case 'P': /* process id */
1915 l = ksprintf(buf, "%u", pid);
1916 if ((n + l) > MAXPATHLEN) {
1917 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n",
1918 pid, name, uid, temp, name);
1919 kfree(temp, M_TEMP);
1920 return NULL;
1921 }
1922 memcpy(temp+n, buf, l);
1923 n += l;
1924 break;
1925 case 'U': /* user id */
1926 l = ksprintf(buf, "%u", uid);
1927 if ((n + l) > MAXPATHLEN) {
1928 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n",
1929 pid, name, uid, temp, name);
1930 kfree(temp, M_TEMP);
1931 return NULL;
1932 }
1933 memcpy(temp+n, buf, l);
1934 n += l;
1935 break;
1936 default:
1937 log(LOG_ERR, "Unknown format character %c in `%s'\n", format[i], format);
1938 }
1939 break;
1940 default:
1941 temp[n++] = format[i];
1942 }
1943 }
1944 temp[n] = '\0';
1945 return temp;
1946 }
1947
1948 /*
1949 * Dump a process' core. The main routine does some
1950 * policy checking, and creates the name of the coredump;
1951 * then it passes on a vnode and a size limit to the process-specific
1952 * coredump routine if there is one; if there _is not_ one, it returns
1953 * ENOSYS; otherwise it returns the error from the process-specific routine.
1954 *
1955 * The parameter `lp' is the lwp which triggered the coredump.
1956 */
1957
1958 static int
1959 coredump(struct lwp *lp, int sig)
1960 {
1961 struct proc *p = lp->lwp_proc;
1962 struct vnode *vp;
1963 struct ucred *cred = p->p_ucred;
1964 struct flock lf;
1965 struct nlookupdata nd;
1966 struct vattr vattr;
1967 int error, error1;
1968 char *name; /* name of corefile */
1969 off_t limit;
1970
1971 STOPEVENT(p, S_CORE, 0);
1972
1973 if (((sugid_coredump == 0) && p->p_flag & P_SUGID) || do_coredump == 0)
1974 return (EFAULT);
1975
1976 /*
1977 * Note that the bulk of limit checking is done after
1978 * the corefile is created. The exception is if the limit
1979 * for corefiles is 0, in which case we don't bother
1980 * creating the corefile at all. This layout means that
1981 * a corefile is truncated instead of not being created,
1982 * if it is larger than the limit.
1983 */
1984 limit = p->p_rlimit[RLIMIT_CORE].rlim_cur;
1985 if (limit == 0)
1986 return EFBIG;
1987
1988 name = expand_name(p->p_comm, p->p_ucred->cr_uid, p->p_pid);
1989 if (name == NULL)
1990 return (EINVAL);
1991 error = nlookup_init(&nd, name, UIO_SYSSPACE, NLC_LOCKVP);
1992 if (error == 0)
1993 error = vn_open(&nd, NULL, O_CREAT | FWRITE | O_NOFOLLOW, S_IRUSR | S_IWUSR);
1994 kfree(name, M_TEMP);
1995 if (error) {
1996 nlookup_done(&nd);
1997 return (error);
1998 }
1999 vp = nd.nl_open_vp;
2000 nd.nl_open_vp = NULL;
2001 nlookup_done(&nd);
2002
2003 vn_unlock(vp);
2004 lf.l_whence = SEEK_SET;
2005 lf.l_start = 0;
2006 lf.l_len = 0;
2007 lf.l_type = F_WRLCK;
2008 error = VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, 0);
2009 if (error)
2010 goto out2;
2011
2012 /* Don't dump to non-regular files or files with links. */
2013 if (vp->v_type != VREG ||
2014 VOP_GETATTR(vp, &vattr) || vattr.va_nlink != 1) {
2015 error = EFAULT;
2016 goto out1;
2017 }
2018
2019 VATTR_NULL(&vattr);
2020 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
2021 vattr.va_size = 0;
2022 VOP_SETATTR(vp, &vattr, cred);
2023 p->p_acflag |= ACORE;
2024 vn_unlock(vp);
2025
2026 error = p->p_sysent->sv_coredump ?
2027 p->p_sysent->sv_coredump(lp, sig, vp, limit) : ENOSYS;
2028
2029 out1:
2030 lf.l_type = F_UNLCK;
2031 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, 0);
2032 out2:
2033 error1 = vn_close(vp, FWRITE);
2034 if (error == 0)
2035 error = error1;
2036 return (error);
2037 }
2038
2039 /*
2040 * Nonexistent system call-- signal process (may want to handle it).
2041 * Flag error in case process won't see signal immediately (blocked or ignored).
2042 */
2043 /* ARGSUSED */
2044 int
2045 sys_nosys(struct nosys_args *args)
2046 {
2047 lwpsignal(curproc, curthread->td_lwp, SIGSYS);
2048 return (EINVAL);
2049 }
2050
2051 /*
2052 * Send a SIGIO or SIGURG signal to a process or process group using
2053 * stored credentials rather than those of the current process.
2054 */
2055 void
2056 pgsigio(struct sigio *sigio, int sig, int checkctty)
2057 {
2058 if (sigio == NULL)
2059 return;
2060
2061 if (sigio->sio_pgid > 0) {
2062 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred,
2063 sigio->sio_proc))
2064 ksignal(sigio->sio_proc, sig);
2065 } else if (sigio->sio_pgid < 0) {
2066 struct proc *p;
2067
2068 lockmgr(&sigio->sio_pgrp->pg_lock, LK_EXCLUSIVE);
2069 LIST_FOREACH(p, &sigio->sio_pgrp->pg_members, p_pglist) {
2070 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, p) &&
2071 (checkctty == 0 || (p->p_flag & P_CONTROLT)))
2072 ksignal(p, sig);
2073 }
2074 lockmgr(&sigio->sio_pgrp->pg_lock, LK_RELEASE);
2075 }
2076 }
2077
2078 static int
2079 filt_sigattach(struct knote *kn)
2080 {
2081 struct proc *p = curproc;
2082
2083 kn->kn_ptr.p_proc = p;
2084 kn->kn_flags |= EV_CLEAR; /* automatically set */
2085
2086 /* XXX lock the proc here while adding to the list? */
2087 SLIST_INSERT_HEAD(&p->p_klist, kn, kn_selnext);
2088
2089 return (0);
2090 }
2091
2092 static void
2093 filt_sigdetach(struct knote *kn)
2094 {
2095 struct proc *p = kn->kn_ptr.p_proc;
2096
2097 SLIST_REMOVE(&p->p_klist, kn, knote, kn_selnext);
2098 }
2099
2100 /*
2101 * signal knotes are shared with proc knotes, so we apply a mask to
2102 * the hint in order to differentiate them from process hints. This
2103 * could be avoided by using a signal-specific knote list, but probably
2104 * isn't worth the trouble.
2105 */
2106 static int
2107 filt_signal(struct knote *kn, long hint)
2108 {
2109 if (hint & NOTE_SIGNAL) {
2110 hint &= ~NOTE_SIGNAL;
2111
2112 if (kn->kn_id == hint)
2113 kn->kn_data++;
2114 }
2115 return (kn->kn_data != 0);
2116 }
DragonFly BSD